Endodontic management of a mandibular third molar fused with a fourth molar.

Science.gov (United States)

Turell, I L; Zmener, O

1999-05-01

Developmental anomalies in permanent molars frequently require surgical intervention. A case of a mandibular third molar fused with a fourth molar which was successfully treated with conservative endodontic therapy is reported.

Sublingual piroxicam in the management of postoperative pain after surgical removal of impacted mandibular third molar.

Science.gov (United States)

Mohammad, Shadab; Singh, Vibha; Wadhwani, Puneet; Tayade, Himanshu P; Rathod, Onkar K

2012-01-01

Surgical removal of impacted mandibular third molar is one of the most commonly performed procedures in oral and maxillofacial surgical practice. The role of preoperative and postoperative medications for management of postoperative complications has been extensively evaluated. To assess the therapeutic effect of a single dose of 40 mg sublingual piroxicam (study group) vs 150 mg oral diclofenac (50 mg thrice a day) (control group) in patients undergoing surgical removal of impacted mandibular third molar. A total of 100 patients with asymptomatic impacted mandibular third molars were randomized into two groups. One group received two 20-mg tablets of piroxicam once daily on the first and second postoperative days, followed by one 20-mg tablet on the third post-operative day. The other group received one tablet of diclofenac 50 mg orally thrice daily on the first, second, and third post-operative days. Repeated extraoral examinations were done for continuous assessment of swelling, trismus, and reduction in pain. Overall impression of the treating physician and the patient regarding efficacy of study drugs were recorded at the end of the study. In the piroxicam group there was >50% reduction in pain on all three days postoperatively. The incidence of swelling and trismus was found to be higher in the control group as compared to the study group. Adverse events, such as gastrointestinal (GI) disturbances, were significantly higher in the diclofenac group (11%) as compared to the piroxicam group (0%). Two sublingual piroxicam 20 mg tablets once daily has better efficacy and tolerability profile than diclofenac 50 mg one tablet thrice daily in the management of pain after surgical removal of impacted mandibular third molar.

Starting with a higher dose of inhaled corticosteroids in primary care asthma treatment

NARCIS (Netherlands)

van der Molen, T; Meyboom-de Jong, B; Mulder, HH; Postma, DS

New British guidelines on the treatment of asthma (9) advocate starting with a higher dose of inhaled corticosteroids in newly detected asthma patients. We investigated whether initiating inhaled steroid treatment with a higher dose is clinically more effective than a lower dose in steroid naive

The true bladder dose: on average thrice higher than the ICRU reference

International Nuclear Information System (INIS)

Barillot, I.; Horiot, J.C.; Maingon, P.; Bone-Lepinoy, M.C.; D'Hombres, A.; Comte, J.; Delignette, A.; Feutray, S.; Vaillant, D.

1996-01-01

The aim of this study is to compare ICRU dose to doses at the bladder base located from ultrasonography measurements. Since 1990, the dose delivered to the bladder during utero-vaginal brachytherapy was systematically calculated at 3 or 4 points representative of bladder base determined with ultrasonography. The ICRU Reference Dose (IRD) from films, the Maximum Dose (Dmax), the Mean Dose (Dmean) representative of the dose received by a large area of bladder mucosa, the Reference Dose Rate (RDR) and the Mean Dose Rate (MDR) were recorded. Material: from 1990 to 1994, 198 measurements were performed in 152 patients. 98 patients were treated for cervix carcinomas, 54 for endometrial carcinomas. Methods: Bladder complications were classified using French Italian Syllabus. The influence of doses and dose rates on complications were tested using non parametric t test. Results: On average IRD is 21 Gy +/- 12 Gy, Dmax is 51Gy +/- 21Gy, Dmean is 40 Gy +/16 Gy. On average Dmax is thrice higher than IRD and Dmean twice higher than IRD. The same results are obtained for cervix and endometrium. Comparisons on dose rates were also performed: MDR is on average twice higher than RDR (RDR 48 cGy/h vs MDR 88 cGy/h). The five observed complications consist of incontinence only (3 G1, 1G2, 1G3). They are only statistically correlated with RDR p=0.01 (46 cGy/h in patients without complications vs 74 cGy/h in patients with complications). However the full responsibility of RT remains doubtful and should be shared with surgery in all cases. In summary: Bladder mucosa seems to tolerate well much higher doses than previous recorded without increased risk of severe sequelae. However this finding is probably explained by our efforts to spare most of bladder mucosa by 1 deg. ) customised external irradiation therapy (4 fields, full bladder) 2 deg. ) reproduction of physiologic bladder filling during brachytherapy by intermittent clamping of the Foley catheter

Reimbursement rates and policies for primary molar pit-and-fissure sealants across state Medicaid programs.

Science.gov (United States)

Chi, Donald L; Singh, Jennifer

2013-11-01

Little is known about Medicaid policies regarding reimbursement for placement of sealants on primary molars. The authors identified Medicaid programs that reimbursed dentists for placing primary molar sealants and hypothesized that these programs had higher reimbursement rates than did state programs that did not reimburse for primary molar sealants. The authors obtained Medicaid reimbursement data from online fee schedules and determined whether each state Medicaid program reimbursed for primary molar sealants (no or yes). The outcome measure was the reimbursement rate for permanent tooth sealants (calculated in 2012 U.S. dollars). The authors compared mean reimbursement rates by using the t test (α = .05). Seventeen Medicaid programs reimbursed dentists for placing primary molar sealants (34 percent), and the mean reimbursement rate was $27.57 (range, $16.00 [Maine] to $49.68 [Alaska]). All 50 programs reimbursed dentists for placement of sealants on permanent teeth. The mean reimbursement for permanent tooth sealants was significantly higher in programs that reimbursed for primary molar sealants than in programs that did not ($28.51 and $23.67, respectively; P = .03). Most state Medicaid programs do not reimburse dentists for placing sealants on primary molars, but programs that do so have significantly higher reimbursement rates. Medicaid reimbursement rates are related to dentists' participation in Medicaid and children's dental care use. Reimbursement for placement of sealants on primary molars is a proxy for Medicaid program generosity.

Fusion of mandibular third molar with supernumerary fourth molar

OpenAIRE

López Carriches, C.; Leco Berrocal, I.; Baca Pérez-Bryan, R.

2008-01-01

La fusión dental es la unión de dos gérmenes dentales normalmente separados, mientras que la geminación se define como el intento de división de un único germen dental. La fusión y geminación de molares es poco frecuente en la dentición permanente. Describimos un caso clínico de un tercer molar inferior derecho fusionado a un cuarto molar supernumerario en un paciente varón de 36 años que ha presentado repetidos episodios de pericoronaritis. Tras el estudio radiológico se realiza la exodoncia...

Double versus single cartridge of 4% articaine infiltration into the retro-molar area for lower third molar surgery.

Science.gov (United States)

Sawang, Kamonpun; Chaiyasamut, Teeranut; Kiattavornchareon, Sirichai; Pairuchvej, Verasak; Bhattarai, Bishwa Prakash; Wongsirichat, Natthamet

2017-06-01

There are no studies regarding 4% articaine infiltration injection into the retro-molar area for an impacted lower third molar (LITM) surgery. This study aimed to evaluate the efficacy of infiltration using 1.7 ml (single cartridge: SC) of 4% articaine versus 3.4 ml (double cartridges: DC) of 4% articaine with 1:100,000 epinephrine in LITM surgery. This study involved 30 healthy patients with symmetrical LITM. The patients were assigned to receive either a DC or SC of 4% articaine with 1:100,000 epinephrine as a local anesthetic for each operation. Onset, duration, profoundness, need for additional anesthetic administration, total volume of anesthetic used, vitality of the tooth, and pain score during operation were recorded. The DC of 4 % articaine had a significantly higher success rate (83.3%) than did the SC (53.3%; P molar region can be an alternative anesthetic for LITM surgery.

[Correlation between the lower first permanent molar axis and the premature loss of temporary molars].

Science.gov (United States)

Petcu, Ana; Maxim, A; Haba, Danisia

2009-01-01

The aim of our study was to determine the impact of premature loss of temporary molars upon the longitudinal axis of the first permanent molar. The study sample was formed by 94 orthopanthomografies of child patients with premature loss of lower temporary molars (first or second) after clinical eruption of the first permanent molar. All panoramic radiographs have been realized with the same panoramic unit with 1.4% magnification coefficient and were analyzed using a standardized technique of tracing the images of teeth and bone on matte acetate paper. It was evaluated the angle between longitudinal axis of first permanent lower molar and occlusal plane. It was observed that premature loss of lower second deciduous molar modifies greater the vertical axis of first permanent molar (between 61 degrees and 79 degrees) then premature loss of first lower primary molar. This is perhaps because the loss of space in the case of premature exfoliation of first primary molar is due more to distal drift of canine then mesial drift of molars. The drift to mesial of first permanent molar is more accentuated proportional with the age at which appeared premature loss and so it is loss of leeway space.

[Hyperthyroidism in molar pregnancy].

Science.gov (United States)

Boufettal, H; Mahdoui, S; Noun, M; Hermas, S; Samouh, N

2014-03-01

Hyperthyroidism is a rare complication of molar pregnancy. We report a 39-year-old woman who presented a thyrotoxic syndrome accompanying a molar pregnancy. Serum thyroid hormones were elevated and returned to normal level after uterine evacuation of a molar pregnancy. The authors detail the role of thyroid stimulating property of human gonadotropin chorionic hormone and its structural changes during the gestational trophoblastic diseases. These changes give the latter the thyroid stimulating properties and signs of hyperthyroidism. Molar pregnancy may be a cause of hyperthyroidism. The diagnosis of molar pregnancy should be a mention to thyrotoxicosique syndrome in a woman of childbearing age. Copyright © 2013. Published by Elsevier SAS.

SECOND MOLAR UPRIGHTING AFTER PREMATURE LOSS OF MANDIBULAR FIRST PERMANENT MOLAR--CASE REPORT.

Science.gov (United States)

Cernei, E R; Mavru, R B; Zetui, Irina Nicoleta

2015-01-01

Uprighting a tipped molar by using an uprighting spring is a fundamental orthodontic treatment technique. Following a weak anchorage done only by the anterior teeth the permanent lower second molar will rotate around its center of resistance, and besides the distalizing movement will occur its extrusion. Following the reaction, the mandibular anterior teeth will have a movement of intrusion. All these elements will lead to anterior open bite. Correction of vertical problems has become easier with the advent of mini-implants. U.I patient aged 24 years presenting for aesthetic and functional disorders. Clinical examination reveals intraoral Class I molar malocclusion on the right sight, upper narrowing arch with a slight overbite, and the both permanent first molars on the left side lost prematurely. The tooth 37 is inclined at 600 degrees to the plane of occlusion. To avoid front opening occlusion we used an orthodontic miniscrew inserted between the canine and the first premolar on the same side to achieve the second molar up righting. Lower second molar uprighting was achieved without unwanted movements in anterior mandibular region and without molar extrusion. Using mini implants in uprighting a tipped molar will achieve the desired tooth movement and will reduce the number of unwanted side effects and eventually to improve patient's esthetics.

Comparison of the efficacy of low doses of methylprednisolone, acetaminophen, and dexketoprofen trometamol on the swelling developed after the removal of impacted third molar.

Science.gov (United States)

Eroglu, Cennet-Neslihan; Ataoglu, Hanife; Yildirim, Gulsun; Kiresi, Demet

2015-09-01

The aim of the present study was to compare the efficacy of low doses of methylprednisolone, acetaminophen and dexketoprofen trometamol, which are among the drug groups used in our clinic, on postoperative swelling developing after removal of impacted third molar. The three group of patients received either 40 mg methylprednisolone or 300 mg acetaminophen or 12.5 mg dexketoprofen trometamol one hour before the procedure, according to the patient groups. The patients in the methylprednisolone group were injected with methylprednisolone at a dose of 20 mg 24 hour after the procedure and prescribed 300 mg acetaminophen as rescue analgesic. During the postoperative period, the doses that were given before the procedure were continued 3 times a day for 2 days in the acetaminophen and dexketoprofen trometamol groups. Maximal swelling was assessed preoperatively and at the postoperative 48 hours by ultrasound images. Swelling was 34% lower in the methylprednisolone than in the other groups; however, no statistically significant difference was found between the groups. The acetaminophen and dexketoprofen trometamol groups exhibited clinical results close to each other. Combination of low doses of methylprednisolone and acetaminophen provide a safe and adequate clinical success on swelling.

Removable molar power arm

Directory of Open Access Journals (Sweden)

Raj Kumar Verma

2013-01-01

Full Text Available Attachment of force elements from the gingival hook of maxillary molar tubes during the retraction of the anterior teeth is very common in orthodontic practice. As the line of force passes below the center of resistance (CR of molar, it results its mesial tipping and also anchorage loss. To overcome this problem, the line of force should pass along the CR of molar. This article highlights a method to overcome this problem by attaching a removable power arm to the headgear tube of molar tube during the retraction of the anterior teeth.

Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

Science.gov (United States)

Souki, Bernardo Q.; Cheib, Paula L.; de Brito, Gabriela M.; Pinto, Larissa S. M. C.

2015-01-01

Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction. PMID:26321848

Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

Directory of Open Access Journals (Sweden)

Bernardo Q Souki

2015-01-01

Full Text Available Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction.

Peri-operative concerns in a patient with thyroid storm secondary to molar pregnancy

Directory of Open Access Journals (Sweden)

Tanvir Samra

2015-01-01

Full Text Available Awareness of the presence of thyroid function abnormalities in patients with molar pregnancy is important for its prompt diagnosis and management. We report the development of thyroid storm in the immediate post-operative period in a 25-year-old female who underwent evacuation of her molar pregnancy under saddle spinal block after being controlled for her thyrotoxicosis with a combination of antithyroid drugs, iodine, steroids and adrenergic blocking agents. We advocate the use of esmolol infusions up to a maximum dose of 200 μg/kg/min for immediate haemodynamic management of the patient. Optimum time needed for stabilisation of the hyper metabolic state after initiation of antithyroid drugs is still not known and evacuation of molar pregnancy remains the only definitive management of the thyrotoxic state.

The premature loss of primary first molars: space loss to molar occlusal relationships and facial patterns.

Science.gov (United States)

Alexander, Stanley A; Askari, Marjan; Lewis, Patricia

2015-03-01

To investigate space changes with the premature loss of primary first molars and their relationship to permanent molar occlusion and facial forms. Two hundred twenty-six participants (ranging in age from 7 years 8 months to 8 years 2 months; 135 female, 91 male) met all inclusion criteria designed to study space loss as a result of the premature loss of the primary first molar. After 9 months, space loss was evaluated in relationship to molar occlusion and facial form. Statistical evaluation was performed with the paired t-test and with a two-way analysis of variance for independent groups. Patients with leptoprosopic facial form and end-on molar occlusions all exhibited a statistically significant difference when compared to controls in terms of space loss (P molar occlusion displayed space loss as well (P molar occlusion displayed space loss in the maxilla (P molar occlusions showed no significant difference in space loss. The relationship between the first permanent molar occlusion and facial form of the child has an influence on the loss of space at the primary first molar site.

Higher hydrocortisone dose increases bilirubin in hypopituitary patients- results from an RCT.

Science.gov (United States)

Werumeus Buning, Jorien; Kootstra-Ros, Jenny E; Brummelman, Pauline; van den Berg, Gerrit; van der Klauw, Melanie; Wolffenbuttel, Bruce H R; van Beek, André P; Dullaart, Robin P F

2016-05-01

Bilirubin has anti-oxidative and anti-inflammatory properties, which may explain its proposed protective effects on the development of cardiometabolic disorders. Glucocorticoids affect heme oxygenase regulation in vitro, which plays a key role in bilirubin production. Effects of variations in glucocorticoid exposure on circulating bilirubin levels in humans are unknown. Here we tested whether a higher hydrocortisone replacement dose affects circulating bilirubin in hypopituitary patients. A randomized double-blind cross-over study (ClinicalTrials.gov, number NCT01546992) was performed in 47 patients with secondary adrenal failure [10-week exposure to a higher hydrocortisone dose (0·4-0·6 mg/kg body weight) vs. 10 weeks of a lower hydrocortisone dose (0·2-0·3 mg/kg body weight)]. Plasma total bilirubin was increased by 10% from 7 to 8 μM in response to the higher hydrocortisone dose (P = 0·033). This effect was inversely related to age (P = 0·042), but was unaffected by sex, obesity and (replacement for) other hormonal insufficiencies. The higher hydrocortisone dose also resulted in lower alkaline phosphatase (P = 0·006) and aspartate aminotransferase activities (P = 0·001). Bilirubin is modestly increased in response to higher glucocorticoid exposure in humans, in conjunction with lower alkaline phosphatase and aspartate aminotransferase activities, which are supposed to represent biomarkers of a pro-inflammatory state and enhanced liver fat accumulation. © 2016 The Authors. European Journal of Clinical Investigation published by John Wiley & Sons Ltd on behalf of Stichting European Society for Clinical Investigation Journal Foundation.

An innovative technique to distalize maxillary molar using microimplant supported rapid molar distalizer

Directory of Open Access Journals (Sweden)

Meenu Goel

2013-01-01

Full Text Available Introduction: In recent years, enhancements in implants have made their use possible as a mode of absolute anchorage in orthodontic patients. In this paper, the authors have introduced an innovative technique to unilaterally distalize the upper left 1 st molar to obtain an ideal Class I molar relationship from a Class II existing molar relationship with an indigenous designed distalizer. Clinical Innovation: For effective unilateral diatalization of molar, a novel cantilever sliding jig assembly was utilized with coil spring supported by a buccally placed single micro implant. The results showed 3 mm of bodily distalization with 1 mm of intrusion and 2° of distal tipping of upper left 1 st molar in 1.5 months. Discussion: This appliance is relatively easy to insert, well-tolerated, and requires minimal patient cooperation compared to other present techniques of molar distalization. Moreover, it is particularly useful in cases that are Class II on one side and Class I on the other, with a minor midline discrepancy and nominal overjet. Patient acceptance level was reported to be within patients physiological and comfort limits.

Are Hypomineralized Primary Molars and Canines Associated with Molar-Incisor Hypomineralization?

Science.gov (United States)

da Silva Figueiredo Sé, Maria Jose; Ribeiro, Ana Paula Dias; Dos Santos-Pinto, Lourdes Aparecida Martins; de Cassia Loiola Cordeiro, Rita; Cabral, Renata Nunes; Leal, Soraya Coelho

2017-11-01

The purpose of this study was to evaluate the prevalence of and relationship between hypomineralized second primary molars (HSPM) and hypomineralized primary canines (HPC) with molar-incisor hypomineralization (MIH) in 1,963 schoolchildren. The European Academy of Paediatric Dentistry (EAPD) criterion was used for scoring HSPM/HPC and MIH. Only children with four permanent first molars and eight incisors were considered in calculating MIH prevalence (n equals 858); for HSPM/HPC prevalence, only children with four primary second molars (n equals 1,590) and four primary canines (n equals 1,442) were considered. To evaluate the relationship between MIH/HSPM, only children meeting both criteria cited were considered (n equals 534), as was true of MIH/HPC (n equals 408) and HSPM/HPC (n equals 360; chi-square test and logistic regression). The prevalence of MIH was 14.69 percent (126 of 858 children). For HSPM and HPC, the prevalence was 6.48 percent (103 of 1,592) and 2.22 percent (32 of 1,442), respectively. A significant relationship was observed between MIH and both HSPM/HPC (PMIH based on HSPM was 6.31 (95 percent confidence interval [CI] equals 2.59 to 15.13) and for HPC was 6.02 (95 percent CI equals 1.08 to 33.05). The results led to the conclusion that both hypomineralized second primary molars and hypomineralized primary canines are associated with molar-incisor hypomineralization, because children with HSPM/HPC are six times more likely to develop MIH.

Physicochemical characterization of irradiated high molar mass chitosan

International Nuclear Information System (INIS)

Rapado, Manuel; Paredes, Mayte; Altanes, Sonia; Barrera, Gisela; Otero, Isabel; Peniche, Carlos; Gonzalez, Maykel

2006-01-01

The present study is aimed to determination of the bio burden for assessing the sterilization dose and to identify the influence of the absorbed dose of gamma radiation on the molar mass and chemical structure of chitosan. The characterization includes the determination of the intrinsic viscosity, deacetylation degree as well as infrared spectrometry. The obtained results have been shown chain cleavage caused by irradiation. It was revealed by a decrease in the intrinsic viscosities of the polymers. The invariance of the infrared spectra of polymers indicated that chain degradation occurs without significant change of the chemical structure. The results obtained have practical implication in the field of radiation sterilization of chitosan used for microencapsulation of mammalian cells

Mini implant supported molar tubes: A novel method for attaching the molar tubes

Directory of Open Access Journals (Sweden)

Nitin V Muralidhar

2017-01-01

Full Text Available Banding or bonding procedures have been the only means of attaching molar tubes onto the permanent molar teeth till date in the field of orthodontics. This clinical innovation aims to include the use of mini implant for the purpose of attaching the molar tubes thereby eliminating the iatrogenic effects of banding and bonding of the teeth.

Outcomes of intentionally replanted molars according to preoperative locations of periapical lesions and the teeth

Directory of Open Access Journals (Sweden)

WooCheol Lee

2012-06-01

Conclusions: Within the limitations of this study, IR of mandibular molars seemed to provide a higher success rate than that for maxillary molars, regardless of the presence of preoperative periapical lesions.

Warfarin maintenance dose in older patients: higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry.

Science.gov (United States)

Garwood, Candice L; Clemente, Jennifer L; Ibe, George N; Kandula, Vijay A; Curtis, Kristy D; Whittaker, Peter

2010-06-15

Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed. Our chart review examined 170 patients of African ancestry and 49 patients of European ancestry cared for in our anticoagulation clinic. We calculated the average weekly dose required for each stable, anticoagulated patient to maintain an international normalized ratio of 2.0 to 3.0, determined dose averages for groups 80 years of age and plotted dose as a function of age. The maintenance dose in patients of African ancestry decreased with age (PAfrican ancestry required higher average weekly doses than patients of European ancestry: 33% higher in the 70- to 79-year-old group (38.2+/-1.9 vs. 28.8+/-1.7 mg; P=0.006) and 52% in the >80-year-old group (33.2+/-1.7 vs. 21.8+/-3.8 mg; P=0.011). Therefore, 43% of older patients of African ancestry required daily doses >5mg and hence would have been under-dosed using current starting-dose guidelines. The dose frequency distribution was wider for older patients of African ancestry compared to those of European ancestry (PAfrican ancestry indicate that strategies for initiating warfarin therapy based on studies of patients of European ancestry could result in insufficient anticoagulation and thereby potentially increase their thromboembolism risk. Copyright 2010 Elsevier Inc. All rights reserved.

Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.

Science.gov (United States)

Bedenbaugh, John H.; And Others

1988-01-01

Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

Extrações de molares na Ortodontia Molar extractions in orthodontics

Directory of Open Access Journals (Sweden)

Marco Antônio Schroeder

2011-12-01

Full Text Available O tratamento ortodôntico com extração de molares em pacientes adultos é tecnicamente mais complexo, devido a inúmeros fatores. Em geral, o espaço a ser fechado é maior do que o espaço dos pré-molares e, por isso, a ancoragem é crítica e o tempo de tratamento mais longo. É comum esses casos apresentarem algum grau de comprometimento periodontal por causa da idade dos pacientes e, portanto, necessitam de maior controle da mecânica ortodôntica para reduzir os efeitos colaterais do fechamento do espaço. Por isso, bons resultados de finalização são mais difíceis de ser alcançados. Sendo assim, este artigo tem como objetivo apresentar as razões para a indicação de extração de molares nos tratamentos ortodônticos, as contraindicações, as diferentes fases da mecânica ortodôntica, esclarecer os fatores envolvidos nesse tipo de planejamento e tratamento e apresentar casos clínicos tratados com extração de molares.Orthodontic treatment with extraction of molars in adult patients is technically more complex due to a number of factors. In general, the space to be closed is greater than premolar spaces rendering critical anchorage and longer treatment time. Often such cases exhibit some degree of periodontal involvement due to patient age. Hence, the need for greater control over orthodontic mechanics to reduce the side effects of space closure. Therefore, good finishing results can be more difficult to achieve. Thus, the purpose of this article is to determine the reasons for molar extraction indications, describe different stages of orthodontic mechanics, and explain the issues involved in this kind of planning and treatment. Additionally, it aims at describing some treatments with molar extractions.

Molar volume of eutectic solvents as a function of molar composition and temperature☆

Institute of Scientific and Technical Information of China (English)

Farouq S. Mjalli

2016-01-01

The conventional Rackett model for predicting liquid molar volume has been modified to cater for the effect of molar composition of the Deep Eutectic Solvents (DES). The experimental molar volume data for a group of commonly used DES has been used for optimizing the improved model. The data involved different molar compositions of each DES. The validation of the new model was performed on another set of DESs. The average relative deviation of the model on the training and validation datasets was approximately 0.1%while the Rackett model gave a relative deviation of more than 1.6%. The modified model deals with variations in DES molar com-position and temperature in a more consistent way than the original Rackett model which exhibits monotonic performance degradation as temperature moves away from reference conditions. Having the composition of the DES as a model variable enhances the practical utilization of the predicting model in diverse design and process simulation applications.

Molar development in sheep: morphology, radiography, microhardness

International Nuclear Information System (INIS)

Milhaud, G.; Nezit, J.

1991-01-01

The chronology of molar development is studied from radiographic and macroscopic observations on 48 south Pre-Alps were living under optimal nutritional conditions. It was found that the first molar started its development in utero, the second molar at one month after birth, and the third molar, at 9-10 months. The first molar emerged into the oral cavity at 3 months, the second at 9 months and the third molar at 18 months. The first molar began the development of its roots at 6-7 months, the second molar at 11-12 months and the third molar at 20-22 months. The first molar reached completion of the growth of its roots at 3.5-4 years, the second and the third molars at about 6 years. The molars show the particularity of being functional during the three months which follow their eruption although the development of the crown is not completed. Then the accelerated wear is only partially compensated by the growth of the roots. The study also shows how the combined effects of wear and dentine deposit in the pulp cavity affect the morphology of molars. It reveals the marked hardness of enamel (240 Vickers units) and the low resistance of dentine at the surface of attrition (30 Vickers units)

Prevalence of Third Molar Agenesis: Associated Dental Anomalies in Non-Syndromic 5923 Patients.

Science.gov (United States)

Sujon, Mamun Khan; Alam, Mohammad Khursheed; Rahman, Shaifulizan Abdul

2016-01-01

The aim of this study was to investigate the prevalence of third molar agenesis and other associated dental anomalies in Bangladeshi population and to investigate the relationship of other dental anomalies with the third molar presence/agenesis. A retrospective study was performed using panoramic radiographs of 5923 patients, who ranged in age from 10 to 50 years. All radiographs were analyzed by Planmeca Romexis® 3.0 software (Planmeca Oy, Helsinki, Finland). Pearson chi-square and one way ANOVA (Post Hoc) test were conducted. The prevalence of third molar agenesis was 38.4%. The frequency of third molar agenesis was significantly higher in females than males (p dental anomalies was 6.5%, among them hypodontia was 3.1%. Prevalence of third molar agenesis varies in different geographic region. Among the other dental anomalies hypodontia was more prevalent.

Effect of submucosal application of tramadol on postoperative pain after third molar surgery.

Science.gov (United States)

Gönül, Onur; Satılmış, Tülin; Bayram, Ferit; Göçmen, Gökhan; Sipahi, Aysegül; Göker, Kamil

2015-10-14

The aim of this study was to evaluate the effectiveness of submucosal application of tramadol, for acute postoperative facial pain, following the extraction of impacted third molar teeth. This prospective, double-blind, randomised placebo-controlled study included 60 ASA I-II patients undergoing impacted third molar surgery under local anaesthesia. Following the surgical procedure, patients were randomly divided into two groups; group T (1 mg/kg tramadol) and group S (2-mL saline). Treatments were applied submucosally after surgery. Pain after extraction was evaluated using a visual analogue scale (VAS) 0.5, 1, 2, 4, 6, 12, 24, and 48 h postoperatively. The time at which the first analgesic drug was taken, the total analgesic dose used, and adverse tissue reactions were also evaluated. In group T, postoperative VAS scores were significantly lower compared to that in group S (p pain after impacted third molar surgery.

Western Saudi adolescent age estimation utilising third molar development.

Science.gov (United States)

Alshihri, Amin M; Kruger, Estie; Tennant, Marc

2014-07-01

The aim of this study was to establish reference data on third molar morphology/development for age estimation in Western Saudi adolescents, between ages 14 and 23 years of old. The orthopantomograms of 130 individuals (males and females), were examined, and the stage of third molar development were evaluated. Mean ages, standard deviations, and percentile distributions are presented for each stage of development. The mean estimated age for all participants (n = 130) was 219.7 months, and this differed significantly (P age (226.5 months). Deviations of predicted age from real age showed 28.5% of all participants had their age estimated within 1 year (±12 months) of their chronological age. Most (43%) had their age underestimated by more than 12 months and the remaining 28.5% had their age overestimated by more than 12 months of their chronological age. Differences in left-right symmetry information of third molars were detected and were higher in the maxilla (92%) than in the mandible (82%). For all molars reaching stage "H" most individuals (males and females) were over the age 18 years of old. Males reach the developmental stages earlier than females. Third molar tooth development can be reliably used to generate mean age and the estimated age range for an individual of unknown chronological age. Further studies with large populations are needed for better statistical results.

Prevalent of root resorption of second molar adjustment the impacted third molar in prepiacal and panoramic radiographs

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Mohammad Ebrahimi Saravi

2013-10-01

Full Text Available   Background and Aims: Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to root resorption of the adjacent tooth. The purpose of this study was to determine this resorption using panoramic and periapical radiographs.   Materials and Methods: In this cross-sectional descriptive study 54 patient (28 men, 26 women above 15 years old with the average of 22 years in Oral and Maxillofacial Department of Tehran University were studied. A periapical radiography from the third molar and a panoramic radiograph were taken from each patient (Because of their routine use and evaluation of accuracy of panoramic compared with periapical, and the magnitude of the root resorption for the second molar was determined by 2 observers and written in a questionnaire. Data were analyzed using Fisher test.   Results: The prevalence of the root resorption of the second molar adjacent to the impacted third molar in the panoramic and the periapical radiographies, with respect to the limitation of the sample size were 46.3% and 31.5%, respectively, with 95% confidence(P>0.05. Most of these resorptions were in the cervical third of the second molar roots and in cases in which the third molars were mesially oriented or horizontal. There was also no significant difference between panoramic and periapical radiographs.   Conclusion: Due to the increased risk of the resorption of the second molar adjacent to the third molar, extraction of the impacted third molars, especiall y mesially oriented or horizontal ones are recommended.

Analysis of the mineral composition of hypomineralized first permanent molars

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Martinović Brankica

2015-01-01

Full Text Available Background/Aim. Hypomineralization of molars and incisors (molar-incisor hypomineralization - MIH is defined as enamel hypomineralization of systemic origin of one or more of the four first permanent molars, which may be associated with changes in the maxillary, and less frequently in the permanent mandibular incisors. The aim of this study was to investigate the mineral content in hypomineralized teeth as a contribution to under-standing the origin of these changes, which will be important for effective restorative approach. Methods. A total of 10 extracted first permanent molars diagnosed with MIH were used in the study as the experimental group, and intact first premolars extracted for orthodontic reasons were used as the control group. A certain surface of hypomineralized аnd healthy enamel and dentin was analyzed using a scanning electron microscope equipped with an energydispersive spectrometer (SEM/EDS. Results. By conducting quantitative chemical analysis of the distribution of the basic chemical elements, it was found that the concentration of calcium (Ca and phosphorus (P was significantly higher in healthy enamel (Ca = 28.80 wt%, and P = 15.05 wt% compared to hypomineralized enamel (Ca = 27.60 wt% and P = 14.32 wt%. Carbon (C concentration was statistically significantly higher in hypomineralized enamel (C = 11.70 wt% compared to healthy enamel (C = 10.94 wt%. Hypomineralized and healthy enamel did not differ significantly regarding the ratio of calcium and phosphorus concentrations whereas the ratio of calcium and carbon concentrations was statistically significantly higher in healthy enamel compared to hypomineralized enamel. Conclusion. Concentration of the main chemical elements, primarily calcium and phosphorus, is significantly reduced in hypomineralized enamel whereas carbon concentration is increased compared to healthy enamel.

Human dental age estimation combining third molar(s) development and tooth morphological age predictors.

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Thevissen, P W; Galiti, D; Willems, G

2012-11-01

In the subadult age group, third molar development, as well as age-related morphological tooth information can be observed on panoramic radiographs. The aim of present study was to combine, in subadults, panoramic radiographic data based on developmental stages of third molar(s) and morphological measurements from permanent teeth, in order to evaluate its added age-predicting performances. In the age range between 15 and 23 years, 25 gender-specific radiographs were collected within each age category of 1 year. Third molar development was classified and registered according the 10-point staging and scoring technique proposed by Gleiser and Hunt (1955), modified by Köhler (1994). The Kvaal (1995) measuring technique was applied on the indicated teeth from the individuals' left side. Linear regression models with age as response and third molar-scored stages as explanatory variables were developed, and morphological measurements from permanent teeth were added. From the models, determination coefficients (R (2)) and root-mean-square errors (RMSE) were calculated. Maximal-added age information was reported as a 6 % R² increase and a 0.10-year decrease of RMSE. Forensic dental age estimations on panoramic radiographic data in the subadult group (15-23 year) should only be based on third molar development.

Impacted Mandibular Third Molars: Review of Literature and a ...

African Journals Online (AJOL)

were screened, and 50 articles were included in the review. Causes of ... impaction rate is higher for third molars when compared with other teeth. The mandibular .... Hence, the surgical extraction of these impacted teeth has become the most ...

In vitro evaluation of an alternative method to bond molar tubes

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Célia Regina Maio Pinzan-Vercelino

2011-02-01

Full Text Available Despite the advances in bonding materials, many clinicians today still prefer to place bands on molar teeth. Molar bonding procedures need improvement to be widely accepted clinically. OBJECTIVE: The purpose of this study was to evaluate the shear bond strength when an additional adhesive layer was applied on the occlusal tooth/tube interface to provide reinforcement to molar tubes. MATERIAL AND METHODS: Sixty third molars were selected and allocated to the 3 groups: group 1 received a conventional direct bond followed by the application of an additional layer of adhesive on the occlusal tooth/tube interface, group 2 received a conventional direct bond, and group 3 received a conventional direct bond and an additional cure time of 10 s. The specimens were debonded in a universal testing machine. The results were analyzed statistically by ANOVA and Tukey's test (α=0.05. RESULTS: Group 1 had a significantly higher (p0.05. CONCLUSIONS: The present in vitro findings indicate that the application of an additional layer of adhesive on the tooth/tube interface increased the shear bond strength of the bonded molar tubes.

A three-dimensional finite element analysis of molar distalization with a palatal plate, pendulum, and headgear according to molar eruption stage

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Kang, Ju-Man; Park, Jae Hyun; Bayome, Mohamed; Oh, Moonbee; Park, Chong Ook; Mo, Sung-Seo

2016-01-01

Objective This study aimed to (1) evaluate the effects of maxillary second and third molar eruption status on the distalization of first molars with a modified palatal anchorage plate (MPAP), and (2) compare the results to the outcomes of the use of a pendulum and that of a headgear using three-dimensional finite element analysis. Methods Three eruption stages were established: an erupting second molar at the cervical one-third of the first molar root (Stage 1), a fully erupted second molar (Stage 2), and an erupting third molar at the cervical one-third of the second molar root (Stage 3). Retraction forces were applied via three anchorage appliance models: an MPAP with bracket and archwire, a bone-anchored pendulum appliance, and cervical-pull headgear. Results An MPAP showed greater root movement of the first molar than crown movement, and this was more noticeable in Stages 2 and 3. With the other devices, the first molar showed distal tipping. Transversely, the first molar had mesial-out rotation with headgear and mesial-in rotation with the other devices. Vertically, the first molar was intruded with an MPAP, and extruded with the other appliances. Conclusions The second molar eruption stage had an effect on molar distalization, but the third molar follicle had no effect. The application of an MPAP may be an effective treatment option for maxillary molar distalization. PMID:27668192

Incidence of root canal treatment of second molars following adjacent impacted third molar extraction

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Yener Oguz

2016-03-01

Conclusion: Although the incidence is minimal, iatrogenic subluxation injuries occurring during the surgical removal of impacted third molars can lead to pulpal complications and a requirement for root canal treatment of adjacent second molars.

Adhesives for bonded molar tubes during fixed brace treatment.

Science.gov (United States)

Millett, Declan T; Mandall, Nicky A; Mattick, Rye Cr; Hickman, Joy; Glenny, Anne-Marie

2017-02-23

date of publication when searching the electronic databases. Randomised controlled trials of participants with full arch fixed orthodontic appliance(s) with molar tubes, bonded to first or second permanent molars. Trials which compared any type of adhesive used to bond molar tubes (stainless steel or titanium) with any other adhesive, were included.Trials were also included where:(1) a tube was bonded to a molar tooth on one side of an arch and a band cemented to the same tooth type on the opposite side of the same arch;(2) molar tubes had been allocated to one tooth type in one patient group and molar bands to the same tooth type in another patient group. The selection of papers, decision about eligibility and data extraction were carried out independently and in duplicate without blinding to the authors, adhesives used or results obtained. All disagreements were resolved by discussion. Two trials (n = 190), at low risk of bias, were included in the review and both presented data on first time failure at the tooth level. Pooling of the data showed a statistically significant difference in favour of molar bands, with a hazard ratio of 2.92 (95% confidence intervals (CI) 1.80 to 4.72). No statistically significant heterogeneity was shown between the two studies. Data on first time failure at the patient level were also available and showed statistically different difference in favour of molar bands (risk ratio 2.30; 95% CI 1.56 to 3.41) (risk of event for molar tubes = 57%; risk of event for molar bands 25%).One trial presented data on decalcification again showing a statistically significant difference in favour of molar bands. No other adverse events identified. From the two well-designed and low risk of bias trials included in this review it was shown that the failure of molar tubes bonded with either a chemically-cured or light-cured adhesive was considerably higher than that of molar bands cemented with glass ionomer cement. One trial indicated that there was less

Middle mesial canals in mandibular molars: incidence and related factors.

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Nosrat, Ali; Deschenes, Raney J; Tordik, Patricia A; Hicks, M Lamar; Fouad, Ashraf F

2015-01-01

Although the internal anatomy of mandibular molars has been extensively studied, information about middle mesial (MM) canals is limited. The primary aim of this retrospective study was to evaluate the incidence of MM canals in mandibular first and second molars. The secondary aim was to correlate the incidence of MM canals with variables of molar type, sex, age, ethnicity, and presence of a second distal canal. All mature permanent first and second mandibular molars treated from August 2012 to May 2014 were included in the analysis. After completion of root canal instrumentation in all main canals, the clinician inspected the isthmus area of the mesial root using the dental operating microscope. If there was a catch point in this area with a file or explorer, the operator spent more time attempting to negotiate an MM canal. Seventy-five mandibular first and second molars were treated during the specified period. Fifteen (20%) teeth had negotiable MM canals. The incidence of MM canals was 32.1% in patients ≤ 20 years old, 23.8% in patients 21-40 years old, and 3.8% in patients > 40 years. Analysis of data revealed a significant difference in the distribution of MM canals among different age groups (P molar type, and presence of a second distal canal were not significant. The incidence of negotiable MM canals overall and their frequency of identification in younger patients were higher than in previous reports. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Hypomineralized Second Primary Molars as Predictor of Molar Incisor Hypomineralization

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Negre-Barber, A.; Montiel-Company, J. M.; Boronat-Catalá, M.; Catalá-Pizarro, M.; Almerich-Silla, J. M.

2016-01-01

Molar incisor hypomineralization (MIH) is a developmental defect of dental enamel that shares features with hypomineralized second primary molars (HSPM). Prior to permanent tooth eruption, second primary molars could have predictive value for permanent molar and incisor hypomineralization. To assess this possible relationship, a cross-sectional study was conducted in a sample of 414 children aged 8 and 9 years from the INMA cohort in Valencia (Spain). A calibrated examiner (linear-weighted Kappa 0.83) performed the intraoral examinations at the University of Valencia between November 2013 and 2014, applying the diagnostic criteria for MIH and HSPM adopted by the European Academy of Paediatric Dentistry. 100 children (24.2%) presented MIH and 60 (14.5%) presented HSPM. Co-occurrence of the two defects was observed in 11.1% of the children examined. The positive predictive value was 76.7% (63.9–86.6) and the negative predictive value 84.7% (80.6–88.3). The positive likelihood ratio (S/1-E) was 10.3 (5.9–17.9) and the negative likelihood ratio (1-S/E) 0.57 (0.47–0.68). The odds ratio was 18.2 (9.39–35.48). It was concluded that while the presence of HSPM can be considered a predictor of MIH, indicating the need for monitoring and control, the absence of this defect in primary dentition does not rule out the appearance of MIH. PMID:27558479

Reference dose levels for dental periapical radiography in Chonnam Province

International Nuclear Information System (INIS)

Han, Mi Ra; Kang, Byung Cheol; Yoon, Suk Ja; Lee, Jae Seo; Kim, Young Hee

2009-01-01

To establish reference doses of periapical radiography in Chonnam Province, Korea. The target-skin distances were measured for dental patient's 1235 exposures including 345 mandibular molar areas. Each periapical radiation exposure was simulated with exactly the same patients exposure parameters and the simulated radiation doses were measured utilizing Mult-O-Meter (Unfors Instruments, Billadal, Sweden). The measurements were done in 44 dental clinics with 49 dental x-ray sets in Chonnam Province for one or two weeks at each dental clinic during year 2006. The third quartile patient surface doses were 2.8 mGy for overall periapical exposures and 3.2 mGy for periapical mandibular molar exposures. The third quartile patient surface doses in Chonnam Province can be used as a guide to accepted clinical practice to reduce patient radiation exposure for the surveyed reference doses were below the recommended dental periapical radiography dose of 7 mGy by IAEA.

Reference dose levels for dental periapical radiography in Chonnam Province

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Han, Mi Ra; Kang, Byung Cheol; Yoon, Suk Ja [Department of Oral and Maxillofacial Radiology, College of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju (Korea, Republic of); Lee, Jae Seo [Department of Oral and Maxillofacial Radiology, Chonnan National University Hospital, Gwangju (Korea, Republic of); Kim, Young Hee [Department of Oral and Maxillofacial Radiology, Hallym University Sacred Heart Hospital, Chuncheon (Korea, Republic of)

2009-12-15

To establish reference doses of periapical radiography in Chonnam Province, Korea. The target-skin distances were measured for dental patient's 1235 exposures including 345 mandibular molar areas. Each periapical radiation exposure was simulated with exactly the same patients exposure parameters and the simulated radiation doses were measured utilizing Mult-O-Meter (Unfors Instruments, Billadal, Sweden). The measurements were done in 44 dental clinics with 49 dental x-ray sets in Chonnam Province for one or two weeks at each dental clinic during year 2006. The third quartile patient surface doses were 2.8 mGy for overall periapical exposures and 3.2 mGy for periapical mandibular molar exposures. The third quartile patient surface doses in Chonnam Province can be used as a guide to accepted clinical practice to reduce patient radiation exposure for the surveyed reference doses were below the recommended dental periapical radiography dose of 7 mGy by IAEA.

Effect of low-dose dexketoprofen trometamol and paracetamol on postoperative complications after impacted third molar surgery on healthy volunteers: A pilot study

Science.gov (United States)

Durmus, Ercan; Kiresi, Demet

2014-01-01

Objectives: The aim of the present study was to investigate the analgesic and anti-inflammatory effects of dexketoprofen trometamol (DT) and paracetamol on deep acute somatic pain and inflammation in patients undergoing impacted third molar surgery. This study was planned to present benefits that we could obtain with low burden of drug. Study Design: Effects of drugs, which were administered preemptively before the procedure, on pain, mouth-opening limitation, and swelling were assessed by visual analogue scale (VAS), magnetic resonance imaging (MRI), and mouth-opening measurement. Following surgery, time intervals when the patients first need to receive the drug were measured. Results: The VAS scores of the patients were lower in the side treated with DT than that in the paracetamol treated side. There was no significant difference between the groups in terms of mouth-opening limitation. MRI recordings revealed that swelling was lower in the side treated with paracetamol than DT treated side. Conclusions: Administration of the drugs before surgery contributed to the postoperative patient comfort. The analgesic activity of 12.5 mg dose of DT was similar to, even better than, the analgesic activity of 500 mg dose of paracetamol; however, DT had insufficient anti-inflammatory efficacy. Key words:Dexketoprofen trometamol, paracetamol, magnetic resonance imaging. PMID:25129247

CANINE ECTOPIC TREATMENT WITH FIRST MOLAR EXTRACTION

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Angelica Margo

2015-06-01

Full Text Available Decision to extract or not and the type of tooth must be analyzed carefully in orthodontic treatment. Preferable tooth to be extracted was the tooth with large caries or restoration. Usually the type of tooth to be extracted was second molar (if the third molar appears, incisor, first molar, and combination of several teeth. Orthodontic treatment with molar extraction is more difficult to treat and the result is usually compromise. There are several considerations in extracting first molar such as tooth with large caries or restoration, hypoplasia, periapical disease, large discrepancy, high maxilla-mandibular plane angle, and cases with anterior open bite. Nowadays, orthodontic cases with molar extraction do not prolong the treatment time compared to premolar extraction case, but the anchorage system must be considered carefully. The present case was treated with extraction of first molar to solve anterior crowding with maximum anchorage at the upper jaw and using Nance Holding Appliance.

Molar Incisiv Hypomineralisasjon - MIH Litteraturstudie

OpenAIRE

Khan, Aisha Farnaz

2017-01-01

Introduksjon: MIH er definert som emaljehypomineralisering av systemisk opprinnelse der 1 til 4 av første permanente molarer er rammet. Incisiver er også ofte affiserte. Hensikten med denne litteraturstudien er å lage en oversikt over, og vurdere tilgjengelig litteratur om MIH, og bruke litteraturen som bakgrunn for å utarbeide en informasjonsbrosjyre om MIH. Materiale og metode: Det ble utført et elektronisk søk i PubMed med søkestrengene ”Molar incisor hypomineralization MIH” og ”Molar inci...

[Relationship between first molar caries and eating and tooth brushing habits in elementary school children].

Science.gov (United States)

Fujiwara, Aiko; Takeda, Fumi

2010-11-01

The aim of the present study was to elucidate the relationship between eating and tooth brushing habits in the second grade of elementary school with first molar caries in the third to sixth grades. Subjects were 130 students at one elementary school in the Tokai region who were in the second grade in 2002, for which eating and tooth-brushing habits were ascertained by a self-administered questionnaire survey. A follow-up survey was conducted based on the 2002 to 2006 school dental examination record and analyses were performed on data from 104 students without first molar dental caries in the second grade. The incidences of first molar caries in the third grade were higher among students who ate cookies at least once daily or every 2 to 3 days, compared with those who ate cookies once a week or not at all in the second grade. Incidences were also higher among those whose daily frequency of tooth brushing was once or sometimes compared with twice or three times or more. Furthermore, the incidences of first molar caries in the fourth, fifth and sixth grades were higher among students who ate candy at least once daily or every 2 to 3 days, compared with those who ate candy once a week or not at all in the second grade. The intake frequency of cookies was related to the first molar caries in the third grade, and of candy for that in the fourth to sixth grades. Moreover, first molar caries in the third grade were also related to the daily frequency of second-grade tooth brushing. These findings suggest the importance of measures encouraging lower-grade elementary students to establish and maintain habits of tooth brushing and of limiting consumption of sweets, such as cookies and candy, in order to prevent caries in their permanent teeth during elementary school.

Expressly fabricated molar tube bases: enhanced adhesion.

Science.gov (United States)

Sharma, Tarun; Phull, Tarun Singh; Rana, Tarun; Kumar, Varun

2014-06-01

Clinicians, Orthodontists and their patients' parents often expect the best results in the shortest time span possible. Orthodontic bonding of molar tubes has been an acceptable risk in a modern era of refined biomaterials and instrumentation. Although many orthodontists still prefer banding to bonding, it is the failure rate of the tubes on molars which accounts to an impedance in molar bonding. One of the reasons for molar attachment failures is attributed to improper adaptation of the buccal tube base with or without increased thickness of composite. Merits of banding the second molars especially when these are the terminal teeth for anchorage have been overemphasized in the literature. The present article presents a simple and relatively less time consuming technique of preparing molar tubes to be bonded on tooth surfaces which may be quite difficult to isolate especially for bonding, for example, mandibular second molars. The increased surface area of the composite scaffold helps not only in enhanced bond strength but also serves to reduce the incidence of plaque accumulation given the dexterity of invitro preparation. The removal of the occlusal part of the molar tube scaffold helps in prevention of open / raised bite tendencies. The present innovation, therefore, is not merely serendipity but a structured technique to overcome a common dilemma for the clinical orthodontist. The present dictum of banding being superior to molar tube bonding may prove to be futile with trendsetting molar attachments. It is also an established fact that bonding proves to be a lesser expensive modality when compared to banding procedures.

Permanent molars: Delayed development and eruption

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Arathi R

2006-05-01

Full Text Available Delayed development and eruption of all the permanent molars is a rare phenomenon, which can cause disturbance in the developing occlusion. The eruption of permanent first and second molars is very important for the coordination of facial growth and for providing sufficient occlusal support for undisturbed mastication. In the case described, the first permanent molars were delayed in their development and were seen erupting at the age of nine and a half years. Severe disparity between the left and the right side of the dentition with respect to the rate of development of molars were also present.

Radiographic assessment of lower third molar eruption in different anteroposterior skeletal patterns and age-related groups.

Science.gov (United States)

Jakovljevic, Aleksandar; Lazic, Emira; Soldatovic, Ivan; Nedeljkovic, Nenad; Andric, Miroslav

2015-07-01

To analyze radiographic predictors for lower third molar eruption among subjects with different anteroposterior skeletal relations and of different age groups. In total, 300 lower third molars were recorded on diagnostic digital orthopantomograms (DPTs) and lateral cephalograms (LCs). The radiographs were grouped according to sagittal intermaxillary angle (ANB), subject age, and level of lower third molar eruption. The DPT was used to analyze retromolar space, mesiodistal crown width, space/width ratio, third and second molar angulation (α, γ), third molar inclination (β), and gonion angle. The LC was used to determine ANB, angles of maxillar and mandibular prognathism (SNA, SNB), mandibular plane angle (SN/MP), and mandibular lengths. A logistic regression model was created using the statistically significant predictors. The logistic regression analysis revealed a statistically significant impact of β angle and distance between gonion and gnathion (Go-Gn) on the level of lower third molar eruption (P third molar impaction rate was significantly higher in the adult subgroup with the Class II (62.3%) compared with Class III subjects (31.7%; P third molar eruption were measured in Class III subjects. For valid estimation of mandibular third molar eruption, certain linear and angular measures (β angle, Go-Gn), as well as the size of the retromolar space, need to be considered.

False-negative urine human chorionic gonadotropin in molar pregnancy: " The high-dose hook effect" !

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Sujata Narendra Datti

2015-01-01

Full Text Available Failure to detect pregnancy in the emergency situations can have important consequences. These include missing of ectopic pregnancy (the leading cause of first-trimester pregnancy-related maternal death, administration of medications contraindicated in pregnancy, fetal radiation exposure, and medico legal problems. This in turn has led to the dictum to check for pregnancy in all women of child-bearing age group. Urine pregnancy (human chorionic gonadotropin [hCG] test is the commonly used test to rule out pregnancy and has been reported by Griffey et al. in their study to achieve 100% sensitivity and 99.2% specificity in a clinical setting, resulting in a positive predictive value of 98.3% and a negative predictive value of nearly 100%. However, the sensitivity is influenced not only by the quantity of β hCG but on its variants that vary with different weeks of pregnancy. β hCG is present in several variant forms that change in their concentrations at different stages of pregnancy. In spite of its high sensitivity, in the presence of molar pregnancy that is associated with very high levels of β hCG it fails to detect the antigen (β hCG. This is explained by the phenomenon known as "high-dose hook effect" which further leads to delay in diagnosis and treatment. This can be overcome by dilution of the sample. In such cases, diagnosis will be made by serum β hCG and ultrasound (USG. Here, we present a case of gravida 2 para 1 living 1 with 2΍ months amenorrhea with bleeding p/v and pain abdomen of 20 days duration whose urine β hCG was repeatedly negative and diagnosis was made by serum β hCG and USG.

Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

Energy Technology Data Exchange (ETDEWEB)

Blanco, Elena [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Ruso, Juan M. [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: faruso@usc.es; Prieto, Gerardo [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Sarmiento, Felix [Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

2005-12-15

Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature.

Partial molar volumes and partial molar adiabatic compressibilities of a short chain perfluorosurfactant: Sodium heptafluorobutyrate in aqueous solutions at different temperatures

International Nuclear Information System (INIS)

Blanco, Elena; Ruso, Juan M.; Prieto, Gerardo; Sarmiento, Felix

2005-01-01

Density and ultrasound measurements of sodium heptafluorobutyrate in aqueous solutions at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15) K have been obtained. From these results partial molar volumes and isentropic partial molar adiabatic compressibilities were calculated. Deviations from the Debye-Hueckel limiting law provide evidence for limited association at lower concentrations. The change of the partial molar volume and isentropic partial molar adiabatic compressibility upon aggregation was calculated. Variations of the change of partial molar volumes and isentropic partial molar adiabatic compressibility upon aggregation are discussed in terms of temperature

Mini-implant-supported Molar Distalization

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Amit Goyal

2012-01-01

Full Text Available Temporary anchorage devices popularly called mini-implants or miniscrews are the latest addition to an orthodontist′s armamentarium. The following case report describes the treatment of a 16-year-old girl with a pleasant profile, moderate crowding and Angle′s Class II molar relationship. Maxillary molar distalization was planned and mini-implants were used to preserve the anterior anchorage. After 13 months of treatment, Class I molar and canine relation was achieved bilaterally and there was no anterior proclination. Thus, mini-implants provide a viable option to the clinician to carry out difficult tooth movements without any side effects.

Influence of unilateral maxillary first molar extraction treatment on second and third molar inclination in Class II subdivision patients

NARCIS (Netherlands)

Livas, Christos; Pandis, Nikolaos; Booij, Johan Willem; Halazonetis, Demetrios J.; Katsaros, Christos; Ren, Yijin

Objective: To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction. Materials and Methods: Panoramic radiographs of 21 Class II subdivision adolescents (eight

Fracture Resistance of Pulpotomized Primary Molar Restored with Extensive Class II Amalgam Restorations

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F. Mazhari

2008-06-01

Full Text Available Objective: The aim of the present study was to evaluate fracture resistance of pulpoto-mized primary molar teeth restored with extensive multisurface amalgam restorations.Materials and Methods: Eighty extracted carious human primary molar teeth were se-lected forpresent study. Teeth were divided in to eight groups of ten. Mesio- or disto-occlusal and Mesio-occluso-distal cavities with different cavity wall thickness (1.5 or 2.5mm were prepared in both first and second primary molar teeth. After restoring teeth with amalgam, all specimens were stored in distilled water at 37°C for 7 days. Then samples were thermocycled for 1000 cycles from 5°C to 55°C. The specimens then were subjected to a compressive load in a universal testing machine at a crosshead speed of 0.5 mm min-1. ANOVA and t-test were used for statistical analysis.Results: Mean fracture resistance of first and second molar teeth were 975.5 N (SD=368.8 and 1049.2 N (SD=540.1 respectively. In the first molar group, fracture resis-tance of two-surface cavities was significantly more than three-surface cavities (P<0.001, however this difference was not statistically significant in the second molar group. In both first and second molar group, fracture resistance incavities with 2.5 mm wall thickness, was significantly more than the group with 1.5 mm wall thickness.Conclusion: The mean fracture resistance in pulpotomized primary molar restored with amalgam restorations was higher than reported maximum bite force in primary teeth even in extensive multi-surface restorations. Therefore, the teeth with large proximal carious lesions in schoolchildren could be restored with amalgam.

Pulpectomy procedures in primary molar teeth

OpenAIRE

Hany Mohamed Aly Ahmed

2014-01-01

Premature loss of primary molars can cause a number of undesirable consequences including loss of arch length, insufficient space for erupting premolars and mesial tipping of the permanent molars. Pulpectomy of primary molar teeth is considered as a reasonable treatment approach to ensure either normal shedding or a long-term survival in instances of retention. Despite being a more conservative treatment option than extraction, efficient pulpectomy of bizarre and tortuous root canals encased ...

Women Administered Standard Dose Imatinib for Chronic Myeloid Leukemia Have Higher Dose-Adjusted Plasma Imatinib and Norimatinib Concentrations Than Men.

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Belsey, Sarah L; Ireland, Robin; Lang, Kathryn; Kizilors, Aytug; Ho, Aloysius; Mufti, Ghulam J; Bisquera, Alessandra; De Lavallade, Hugues; Flanagan, Robert J

2017-10-01

The standard dose of imatinib for the treatment of chronic-phase chronic myeloid leukemia (CML) is 400 mg·d. A predose plasma imatinib concentration of >1 mg·L is associated with improved clinical response. This study aimed to assess the plasma imatinib and norimatinib concentrations attained in patients with chronic myeloid leukemia administered standard doses of imatinib adjusted for dose, age, sex, body weight, and response. We evaluated data from a cohort of patients treated between 2008 and 2014 with respect to dose, age, sex, body weight, and response. The study comprised 438 samples from 93 patients (54 male, 39 female). The median imatinib dose was 400 mg·d in men and in women. The plasma imatinib concentration ranged 0.1-5.0 mg·L and was below 1 mg·L in 20% and 16% of samples from men and women, respectively. The mean dose normalized plasma imatinib and norimatinib concentrations were significantly higher in women in comparison with men. This was partially related to body weight. Mixed effects ordinal logistic regression showed no evidence of an association between sex and plasma imatinib (P = 0.13). However, there was evidence of an association between sex and plasma norimatinib, with higher norimatinib concentrations more likely in women than in men (P = 0.02). Imatinib therapeutic drug monitoring only provides information on dosage adequacy and on short-term adherence; longer-term adherence cannot be assessed. However, this analysis revealed that approximately 1 in 5 samples had a plasma imatinib concentration <1 mg·L, which was suggestive of inadequate dosage and/or poor adherence and posed a risk of treatment failure. Higher imatinib exposure in women may be a factor in the increased rate of long-term, stable, deep molecular response (undetectable breakpoint cluster-Abelson (BCR-ABL) transcript levels with a PCR sensitivity of 4.5 log, MR4.5) reported in women.

Dental lesions and restorative treatment in molars

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Gheorghiu Irina-Maria

2017-08-01

Full Text Available This article review specific clinical issues of the molar teeth, as well as the therapeutic approach of their pathology. The dental pathology we face in the group of molars is related to: dental caries, dental trauma (crown and crown-root fractures, dental wear phenomena. The therapeutic approach of the molar teeth is represented by: restoration of the loss of hard dental tissues; endodontic treatments of pulpal and periapical complications; surgical treatment. The restorative treatments in molars are: direct restorations, with or without supplementary anchorage for obturations; inlay, onlay; prosthetic crown.

Controlled, Rapid Uprighting of Molars: A surprisingly Simple Solution The Pivot Arm Appliance.

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Warise, Timothy R; Galella, Steve A

2015-01-01

In orthodontic cases where the regional anatomy provides limited room for eruption, there is etiologically a higher occurrence of tipped/impacted second molars. Although second molar extraction with third molar replacement is a useful option, the "Pivot Arm Appliance" encourages the uprighting of the second molar as a preferred treatment. The most unique and important attribute of the "Pivot Arm Appliance" is the rotating tube. In cases of access limitation, the disto-occlusal surface of the molar presents as one area that is accessible. Other features of the "Pivot Arm Appliance" include: The position of the rotator tube delivers optimal rotational force through the pivoting action of the tube/arm complex. The "Pivot Arm Appliance" takes advantage of the efficiency and simplicity of a Class I lever system. The anatomical fulcrum being the dense cortical bone located anterior to the ascending ramus. The vertical spring system is compact, reliable and delivers gentle controlled force in rotational direction. The lingual location of the "Pivot Arm Appliance" does not hinder the function of the tongue, impinge on the soft tissue or interfere with normal masticatory function. The ease of placement of the rotator tube and subsequent insertion of the spring. It is well to note the uprighting appliance provides a very useful and practical approach to the unique problem of severely tipped second molars with limited buccal access. The "Pivot Arm Appliance" does not function only in these situations but can be used in all cases of second molar uprighting of a moderate to severe nature.

Autogenous transplantation of maxillary and mandibular molars.

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Reich, Peter P

2008-11-01

Autogenous tooth transplantation has been used as a predictable surgical approach to correct malocclusion and replace edentulous areas. This article focuses on the surgical approach and technique for molar transplantation. Thirty-two patients aged between 11 and 25 years underwent 44 autogenous molar transplantations. The procedure involved transplantation of impacted or newly erupted third molars into the extraction sockets of nonrestorable molars and surgical removal and replacement of horizontally impacted molars into their proper vertical alignment. Five basic procedural concepts were applied: 1) atraumatic extraction, avoiding disruption of the root sheath and root buds; 2) apical contouring of bone at the transplantation site and maxillary sinus lift via the Summers osteotome technique, when indicated, for maxillary molars; 3) preparation of a 4-wall bony socket; 4) avoidance of premature occlusal interferences; and 5) stabilization of the tooth with placement of a basket suture. All 32 patients successfully underwent the planned procedure. To date, 2 patients have had localized infection that resulted in loss of the transplant. The remaining 42 transplants remain asymptomatic and functioning, with a mean follow-up period of 19 months. No infection, ankylosis, loss of the transplant, or root resorption has been noted. In addition, endodontic therapy has not been necessary on any transplanted teeth. Autogenous tooth transplantation has been discussed and described in the literature previously, with a primary focus on cuspid and bicuspid transplantation. The molar transplant is infrequently discussed in today's literature, possibly because of the preponderance of titanium dental implants. Autogenous molar transplantation is a viable procedure with low morbidity and excellent functional and esthetic outcomes. This report shows the successful transplantation of 42 of 44 molars in 32 patients with a mean follow-up period of 19 months.

Does fixed retention prevent overeruption of unopposed mandibular second molars in maxillary first molar extraction cases?

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Livas, Christos; Halazonetis, Demetrios J; Booij, Johan W; Katsaros, Christos; Ren, Yijin

2016-01-01

BACKGROUND: The objective of this study was to investigate whether multistranded fixed retainers prevented overeruption of unopposed mandibular second molars in maxillary first molar extraction cases. METHODS: The panoramic radiographs of 65 Class II Division 1 Caucasian Whites (28 females, 37

Maxillary molar distalization with first class appliance.

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Ramesh, Namitha; Palukunnu, Biswas; Ravindran, Nidhi; Nair, Preeti P

2014-02-27

Non-extraction treatment has gained popularity for corrections of mild-to-moderate class II malocclusion over the past few decades. The distalization of maxillary molars is of significant value for treatment of cases with minimal arch discrepancy and mild class II molar relation associated with a normal mandibular arch and acceptable profile. This paper describes our experience with a 16-year-old female patient who reported with irregularly placed upper front teeth and unpleasant smile. The patient was diagnosed to have angles class II malocclusion with moderate maxillary anterior crowding, deep bite of 4 mm on a skeletal class II base with an orthognathic maxilla and retrognathic mandible and normal growth pattern. She presented an ideal profile and so molar distalization was planned with the first-class appliance. Molars were distalised by 8 mm on the right and left quadrants and class I molar relation achieved within 4 months. The space gained was utilised effectively to align the arch and establish a class I molar and canine relation.

Ibuprofen versus Acetaminophen in Controlling Postoperative Impacted Third Molar Tooth Extraction Pain

International Nuclear Information System (INIS)

Khan, I.; Bukhari, S. G. A.; Ahmad, W.; Rubbab,; Junaid, M.

2013-01-01

Objectives: To compare the efficacy of ibuprofen and acetaminophen in reducing postoperative third molar extraction pain in patients reporting to Armed Forces Institute of Dentistry. Study design: Randomized controlled trial. Place and duration of study: The study was carried out on patients who presented for surgical removal of impacted teeth at Armed Forces Institute of Dentistry Rawalpindi (AFID) from February 2008 to March 2--9 at the Department of Oral Surgery, Armed Forces Institute of Dentistry Rawalpindi. Patients and methods: One hundred and forty patients requiring surgical removal of mandibular impacted teeth were equally divided into two groups. Surgical extraction of third molar tooth was performed under local anesthesia. Patients in group A were given ibuprofen and in group B were given acetaminophen at 6 hourly intervals. First dose was given 3 hours postoperatively. Each patient rated pain on a visual analog scale at baseline and then at 12, 24, 48 and 72 hours postoperatively. Results: There was statistically significant difference (p=0.025) during first 12 hours with ibuprofen group showing better efficacy but afterwards there was no significant difference in the efficacy of both drugs. Conclusions: Ibuprofen is more effective in controlling severe third molar extraction pain as compared to acetaminophen but has similar efficacy in controlling moderate pain. (author)

Association between Peritonsillar Abscess and Molar Caries

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M Shayani Nasab

2006-05-01

Full Text Available Background: Peritonsillar abscess is the most common deep neck infections that are related with periodontal disease which has the same pathogenesis. We determined the relationship between peritonsillar infection and molar caries. Methods: In a cross-sectional study, 33 consecutive patients whom referred to Hamadan university clinic of otolaryngologic for peritonsillar abscess were examined by otolaryngologist and dentist who investigated relationship between peritonsillar infection and molar caries. Results: There were 27 males and 6 females with mean age 26.7+_7 years. The frequency caries on ipsilateral peritonsillar infection sides was in relation to molars caries on opposite sides (conterol group. This corrolation was significant with odds ratio 2.5. Conclusion: Molar caries were seen 2.5 times more likely to have peritonsillar infection compared with normal molar sides. Key Words: Peritonsillar abscess, Infection, Periodontal disease, Dental caries

Evaluation of dose to tooth enamel from medical diagnostic X-ray examinations at Mayak PA

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Wieser, A., E-mail: wieser@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Vasilenko, E. [Mayak Production Association, 456780 Ozyorsk (Russian Federation); Zankl, M.; Greiter, M.; Ulanovsky, A. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Sabayev, A.; Knyazev, V.; Zahrov, P. [Mayak Production Association, 456780 Ozyorsk (Russian Federation)

2011-09-15

The nuclear workers of the Mayak Production Association had regular check-ups including medical diagnostic X-ray examinations since start of the production lines in 1948. Doses from diagnostic examinations need to be considered in reconstruction of occupational doses of the workers with electron paramagnetic resonance (EPR) of tooth enamel. The numbers and types of examinations of an individual worker can be assessed from the Mayak PA archives but no information was available on doses delivered to teeth by a single specific examination. Of the twenty one applied examination procedures only three affected the teeth, these being X-ray examinations of teeth, skull and cervical spine. For these three kinds of examinations operational procedures and operating modes of X-ray units were compiled from the archive and photon spectra were obtained from a catalog of spectral data for diagnostic X-rays. Entrance doses in air kerma were calculated using the fluence of photon spectra and absorbed dose in tooth enamel for various tooth positions and exposure geometry was then calculated using dose conversion coefficients obtained from Monte Carlo simulations. Doses were calculated for examinations in 1948-2000. Except for examination of the skull, absorbed doses in enamel of incisors were found to be about twice as large as in enamel of molars. In the period before 1970 the largest mean absorbed doses in tooth enamel were due to X-ray examination of teeth, with 64 mGy and 34 mGy calculated for incisors and molars, respectively. In the same period the lowest mean doses were due to X-ray examination of the skull, with 11 mGy and 12 mGy calculated for incisors and molars, respectively. In the period from 1970 to 2000, largest mean doses in enamel were due to X-ray examination of cervical spine, with 23 mGy and 12 mGy calculated for incisors and molars, respectively.

The visibility of mandibular canal on orthoradial and oblique CBCT slices at molar implant sites

International Nuclear Information System (INIS)

Alkhader, Mustafa; Jarab, Fadi; Shaweesh, Ashraf; Hudieb, Malik

2016-01-01

The aim of the present study was to compare visibility of the mandibular canal on cone beam computed tomography (CBCT)-based orthoradial and oblique slices at molar implant sites. CBCT images for 132 mandibular molar implant sites were selected for the study. After generating orthoradial and oblique slices, two observers evaluated the visibility of the mandibular canal using three-point scoring scale (1-3, good to excellent). Wilcoxon signed-rank test compared the visibility scores of the two slices. Both orthoradial and oblique slices obtained from CBCT had only very good to excellent mandibular canal visibility scores. At 114 mandibular molar implant sites, the visibility score was equal on both orthoradial and oblique slices. Although the visibility score was higher on orthoradial slices for 12 implant sites, the visibility score was higher for six implant sites on oblique slices and the difference was not significant. Therefore, the visibility of the mandibular canal was excellent and comparable on most of orthoradial and oblique slices obtained from CBCT images

Absorption of Nickel, Chromium, and Iron by the Root Surface of Primary Molars Covered with Stainless Steel Crowns

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David Keinan

2010-01-01

Full Text Available Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1 mm apically to the crown or the cemento-enamel junction (CEJ, was analyzed. An energy dispersive X-ray spectrometer (EDS was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (<.001. Significance. Stainless-steel crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible.

Radiologic study of mandibular third molar of Korean youths

International Nuclear Information System (INIS)

Ahn, Hyung Kyu

1982-01-01

The author has made a study on the classification of the mandibular 3rd molars of Korean youths through dental radiography by means of Pell and Gregory's classification and on the prevalence of the dental caries of distal surface of the mandibular 2nd molar adjacent to the mandibular 3rd molars turned anteriorly. The results are as follow; 1. It was found that the largest case number was class I (272 cases, 52.9%) in the relation of the tooth to the ramus of the mandible and 2nd molar. 2. The mesio-angular position was the largest number (239 cases, 46.5%) in the relation of the long axis of the impacted mandibular 3rd molar to the long axis of the 2nd molar. 3. The mesio-angular position of class I was the largest number (140 cases, 27.2%) in the relation of the tooth to the ramus of the mandible and 2nd molar and the long axis of the impacted mandibular 3rd moral to the long axis of the 2nd molar. 4. The average angle of the long axis of mandibular 3rd molar in mesioangular position or horizontal position to the occlusal plane was 143 W 5. Mandibular 3rd molar with lesion such as dental cries or pericoronitis was 73 cases (14.2). 6. The caries incidence rate of the distal surface of the 2nd molar was about 3.1%.

Third molar development: measurements versus scores as age predictor.

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Thevissen, P W; Fieuws, S; Willems, G

2011-10-01

Human third molar development is widely used to predict chronological age of sub adult individuals with unknown or doubted age. For these predictions, classically, the radiologically observed third molar growth and maturation is registered using a staging and related scoring technique. Measures of lengths and widths of the developing wisdom tooth and its adjacent second molar can be considered as an alternative registration. The aim of this study was to verify relations between mandibular third molar developmental stages or measurements of mandibular second molar and third molars and age. Age related performance of stages and measurements were compared to assess if measurements added information to age predictions from third molar formation stage. The sample was 340 orthopantomograms (170 females, 170 males) of individuals homogenously distributed in age between 7 and 24 years. Mandibular lower right, third and second molars, were staged following Gleiser and Hunt, length and width measurements were registered, and various ratios of these measurements were calculated. Univariable regression models with age as response and third molar stage, measurements and ratios of second and third molars as predictors, were considered. Multivariable regression models assessed if measurements or ratios added information to age prediction from third molar stage. Coefficients of determination (R(2)) and root mean squared errors (RMSE) obtained from all regression models were compared. The univariable regression model using stages as predictor yielded most accurate age predictions (males: R(2) 0.85, RMSE between 0.85 and 1.22 year; females: R(2) 0.77, RMSE between 1.19 and 2.11 year) compared to all models including measurements and ratios. The multivariable regression models indicated that measurements and ratios added no clinical relevant information to the age prediction from third molar stage. Ratios and measurements of second and third molars are less accurate age predictors

Bilateral maxillary fused second and third molars: a rare occurrence.

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Liang, Rui-Zhen; Wu, Jin-Tao; Wu, You-Nong; Smales, Roger J; Hu, Ming; Yu, Jin-Hua; Zhang, Guang-Dong

2012-12-01

This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the second molar. However, CBCT revealed that a third molar was fused to the second molar. Unexpectedly, the maxillary left third molar also was fused to the second molar, and the crown of an unerupted supernumerary fourth molar was possibly also fused to the apical root region of the second molar. Operative procedures should not be attempted without adequate radiographic investigation. CBCT allowed the precise location of the root canals of the right maxillary fused molar teeth to permit successful endodontic therapy, confirmed after 6 months.

Autotransplantation of Mandibular Third Molar: A Case Report

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Pabbati Ravi kumar

2012-01-01

Full Text Available Autogenous transplantation is a feasible, fast, and economical option for the treatment of nonsalvageable teeth when a suitable donor tooth is available. This paper presents successful autotransplantation of a mature mandibular left third molar (38 without anatomical variances is used to replace a mandibular left second molar (37. The mandibular second molar was nonrestorable due to extensive root caries and resorption of distal root. After extraction of mandibular second and third molars, root canal therapy was done for the third molar extraorally, and the tooth was reimplanted into the extracted socket of second molar site. After one year, clinical and radiographic examination revealed satisfactory outcome with no signs or symptoms suggestive of pathology. In selected cases, autogenous tooth transplantation, even after complete root formation of the donor tooth, may be considered as a practical treatment alternative to conventional prosthetic rehabilitation or implant treatment.

Survival of sealants in molars affected by molar-incisor hypomineralization: 18-month follow-up

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Camila Maria Bullio FRAGELLI

2017-04-01

Full Text Available Abstract The objective of this study was to evaluate the clinical survival of sealants applied in first permanent molars (FPMs affected by molar-incisor hypomineralization (MIH, at 18 months of follow-up. Forty-one first permanent molars were selected from 21 children, 6–8 years of age. MIH was classified by one calibrated examiner (kappa = 0.80 according to EAPD criteria. The inclusion criteria were fully erupted FPMs with MIH or sound FPMs (without MIH for which sealant treatment was indicated. The FPMs were assigned to two groups: CG (control group and HG (MIH group. Both groups were treated with sealant (FluroShield. Clinical follow-up was performed from baseline to 18 months to assess anatomical form, marginal adaptation, retention and presence of caries, according to criteria set by the United States Public Health Service-Modified, and was conducted by a blinded examiner (kappa = 0.80. The actuarial method was used to evaluate the survival of the sealants. The survival rates for the groups were compared using Fisher’s exact test (α = 5%. The cumulative survival rates were 81% at 1 month, 68.8% at 6 months, 68.8% at 12 months, and 62.6% at 18 months for CG, and 88% at 1 month, 84% at 6 months, 76% at 12 months, and 72% at 18 months for HG. No significant difference was found between the groups. The sealants in molars affected by MIH presented a survival rate similar to the sealants in the control, suggesting that sealants may be an adequate approach for preventing carious lesions in MIH-affected molars.

Managing molar-incisor hypomineralization: A systematic review.

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Elhennawy, Karim; Schwendicke, Falk

2016-12-01

We systematically reviewed treatment modalities for MIH-affected molars and incisors. Trials on humans with ≥1 MIH molar/incisor reporting on various treatments were included. Two authors independently searched and extracted records. Sample-size-weighted annual failure rates were estimated where appropriate. The risk of bias was assessed using the Newcastle-Ottawa scale. Electronic databases (PubMed, Embase, Cochrane CENTRAL, Google Scholar) were screened, and hand searches and cross-referencing performed. Fourteen (mainly observational) studies were included. Ten trials (381 participants) investigated MIH-molars, four (139) MIH-incisors. For molars, remineralization, restorative or extraction therapies had been assessed. For restorative approaches, mean (SD) annual failure rates were highest for fissure sealants (12[6]%) and glass-ionomer restorations (12[2]%), and lowest for indirect restorations (1[3]%), preformed metal crowns (1.3 [2.1]%) and composite restorations (4[3]%). Ony study assessed extraction of molars in young patients (median age 8.2 years), the majority of them without malocclusions, but third molars in development. Spontaneous alignment of second molars was more frequent in the maxilla (55%) than the mandible (47%). For incisors, desensitizing agents successfully managed hypersensitivity. Micro-abrasion and composite veneers improved aesthetics. Few, mainly moderate to high-risk-studies investigated treatment of MIH. Remineralization or sealants seem suitable for MIH-molars with limited severity and/or hypersensitivity. For severe cases, restorations with composites or indirect restorations or preformed metal crowns seem suitable. Prior to tooth extraction as last resort factors like the presence of a general malocclusion, patients' age and the status of neighboring teeth should be considered. No recommendations can be given for MIH-incisors. Dentists need to consider the specific condition of each tooth and the needs and expectations of

A Molar Pregnancy within the Fallopian Tube

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Laura Allen

2016-01-01

Full Text Available Background. Discussion of the incidence of molar pregnancy and ectopic pregnancy. Role of salpingostomy and special considerations for postoperative care. Case. The patient is a 29-year-old G7P4 who presented with vaginal bleeding in the first trimester and was initially thought to have a spontaneous abortion. Ultrasound was performed due to ongoing symptoms and an adnexal mass was noted. She underwent uncomplicated salpingostomy and was later found to have a partial molar ectopic pregnancy. Conclusion. This case illustrates the rare occurrence of a molar ectopic pregnancy. There was no indication of molar pregnancy preoperatively and this case highlights the importance of submitting and reviewing pathological specimens.

Taking advantage of an unerupted third molar: a case report

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Igor Figueiredo Pereira

Full Text Available ABSTRACT Introduction: Treatments with dental surgery seek to displace tooth to the correct position within the dental arch. Objective: To report a clinical case that took advantage of an unerupted third molar. Case history: A male patient, 18 years of age, was referred by his dentist to evaluate the third molars. The clinical exam revealed no visible lower third molars. The computed tomography (CT exam showed the presence of a supernumerary tooth in the region of the mandibular ramus, on the left side, and impaction of the third molar, which was causing root resorption on the second molar, thus making it impossible to remain in the buccal cavity. The preferred option, therefore, was to remove both second molar and the supernumerary tooth, in addition to attaching a device to the third molar during surgery for further traction. Results: After 12 months, the third molar reached the proper position. Conclusion: When a mandibular second permanent molar shows an atypical root resorption, an impacted third molar can effectively substitute the tooth by using an appropriate orthodontic-surgical approach.

Prevalence of cheese molars in eleven-year-old Dutch children.

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Weerheijm, K L; Groen, H J; Beentjes, V E; Poorterman, J H

2001-01-01

In the Netherlands, first permanent molars with idiopathic enamel disturbances (IED) are called cheese molars. Though concern is expressed about their prevalence, adequate figures on the subject are missing. The porous enamel of cheese molars can be very sensitive to cold air and can decay rapidly. The aim of the present study was to investigate the prevalence in eleven-year-old Dutch children of cheese molars (IED). During an epidemiological study performed in four cities in the Netherlands, the first permanent molars and central incisors of eleven-year-old children were examined for hypoplasia, opacities, posteruptive enamel loss, premature extraction, and atypical restorations. The observation of a hypoplasia excluded the possibility of cheese molar. A total of 497 children were examined. Six percent (n = 128) of the molars (n = 1988) showed signs of IED (cheese molars), 10 percent of the children had cheese molars of which 8 percent two or more. Incisors (4 percent) with opacities were found in 3 percent in combination with two or more cheese molars. Among the four cities, no significant differences in occurrence were found. The results of this study showed that in 10 percent of the Dutch children eleven years of age, cheese molars (IED) were found. The cause for the phenomenon called cheese molars appears to be child centered. Further studies on prevalence, causes and prevention are mandatory.

Excess molar volumes and partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and p = 0.1 MPa

International Nuclear Information System (INIS)

Deenadayalu, N.; Bhujrajh, P.

2006-01-01

The excess molar volumes and the partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and at atmospheric pressure are reported. The hydrogen bonding between the OH133;NC groups are discussed in terms of the chain length of the alkanol. The alkanols studied are (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 1-pentanol). The excess molar volume data was fitted to the Redlich-Kister equation The partial molar volumes were calculated from the Redlich-Kister coefficients

External and internal anatomy of third molars.

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Guerisoli, D M; de Souza, R A; de Sousa Neto, M D; Silva, R G; Pécora, J D

1998-01-01

The external and internal anatomy of 269 third molars (155 maxillary and 114 mandibular) were studied. The teeth were measured, classified according to their root number and shape and the internal anatomy was observed by the use of diaphanization. A great anatomical variability was found, with the presence of up to 5 roots in maxillary third molars and 3 roots in mandibular third molars. The number of root canals followed the same pattern.

Bioavailability of higher dose methotrexate comparing oral and subcutaneous administration in patients with rheumatoid arthritis

NARCIS (Netherlands)

Hoekstra, Monique; Haagsma, C.; Neef, C; Proost, Johannes H; Knuif, A.; van der Laar, M.

Objective. To determine the bioavailability of higher oral doses of methotrexate (MTX) in adult patients with rheumatoid arthritis (RA). Methods. A pharmacokinetic analysis was performed in 15 patients with RA taking a stable dose of MTX (greater than or equal to25 mg weekly). Separated by 2 weeks,

Elastic properties and molar volume of rare-earth aluminosilicae glasses

International Nuclear Information System (INIS)

Tanabe, S.; Hirao, K.; Soga, N.

1992-01-01

This paper reports on the elastic properties, molar volume, and glass transition temperature (T g ) of rare-earth-containing aluminosilicate glasses that were investigated in the compositions of SiO 2 --LnAlO 3 and SiO 2 --Ln 3/4 Al 5/4 O 3 , where Ln is Y, La, Nd, Eu, or Yb. The molar volume decreased with decreased ionic size of the Ln 3+ ion, and T g and elastic moduli increased in the same order. The Yb-containing glasses showed the highest Young's modulus among all the oxide glasses, even higher than the highest value ever known fro glass containing Y 2 O 3 , as expected from the smaller ionic radius of Yb 3+ than that of Y 3+ . The bulk modulus was found to be almost proportional to the inverse four-thirds power of the molar volume of glasses in each composition, indicating that Ln 3+ ions can substitute for each other without changing the glass structure except for the size of the local structure around themselves. From the comparison of these properties, the structural role of rate-earth ions in these glasses is discussed

Characterization of stem and progenitor cells in the dental pulp of erupted and unerupted murine molars

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Balic, Anamaria; Aguila, H. Leonardo; Caimano, Melissa J.; Francone, Victor P.; Mina, Mina

2010-01-01

In the past few years there have been significant advances in the identification of putative stem cells also referred to as “mesenchymal stem cells” (MSC) in dental tissues including the dental pulp. It is thought that MSC in dental pulp share certain similarities with MSC isolated from other tissues. However, cells in dental pulp are still poorly characterized. This study focused on the characterization of progenitor and stem cells in dental pulps of erupted and unerupted mice molars. Our study showed that dental pulps from unerupted molars contain a significant number of cells expressing CD90+/CD45-, CD117+/CD45-, Sca-1+/CD45- and little if any CD45+ cells. Our in vitro functional studies showed that dental pulp cells from unerupted molars displayed extensive osteo-dentinogenic potential but were unable to differentiate into chondrocytes and adipocytes. Dental pulp from erupted molars displayed a reduced number of cells, contained higher percentage of CD45+ and lower percentage of cells expressing CD90+/CD45-, CD117+/CD45- as compared to unerupted molars. In vitro functional assays demonstrated the ability of a small fraction of cells to differentiate into odontoblasts, osteoblasts, adipocytes and chondrocytes. There was a significant reduction in the osteo-dentinogenic potential of the pulp cells derived from erupted molars compared to unerupted molars. Furthermore, the adipogenic and chondrogenic differentiation of pulp cells from erupted molars was dependent on a long induction period and infrequent. Based on these findings we propose that the dental pulp of the erupted molars contain a small population of multipotent cells, whereas the dental pulp of the unerupted molars does not contain multipotent cells but is enriched in osteo-dentinogenic progenitors engaged in the formation of coronal and radicular odontoblasts. PMID:20193787

Analysis of C-shaped root canal configuration in maxillary molars in a Korean population using cone-beam computed tomography

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Hyoung-Hoon Jo

2016-02-01

Full Text Available Objectives The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT in a Korean population. Materials and Methods Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.. The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test. Results Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001. Conclusions In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients.

Science.gov (United States)

Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong

2013-12-01

This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

A High Molar Extinction Coefficient Mono-Anthracenyl Bipyridyl Heteroleptic Ruthenium(II Complex: Synthesis, Photophysical and Electrochemical Properties

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Peter A. Ajibade

2011-06-01

Full Text Available In our quest to develop good materials as photosensitizers for photovoltaic dye-sensitized solar cells (DSSCs, cis-dithiocyanato-4-(2,3-dimethylacrylic acid-2,2'-bipyridyl-4-(9-anthracenyl-(2,3-dimethylacrylic-2,2'-bipyridyl ruthenium(II complex, a high molar extinction coefficient charge transfer sensitizer, was designed, synthesized and characterized by spectroscopy and electrochemical techniques. Earlier studies on heteroleptic ruthenium(II complex analogues containing functionalized oligo-anthracenyl phenanthroline ligands have been reported and documented. Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, herein, we report the photophysical and electrochemical properties of a Ru(II bipyridyl complex analogue with a single functionalized anthracenyl unit. Interestingly, the complex shows better broad and intense metal-to ligand charge transfer (MLCT band absorption with higher molar extinction coefficient (λmax = 518 nm, e = 44900 M−1cm−1, and appreciable photoluminescence spanning the visible region than those containing higher anthracenyl units. It was shown that molar absorption coefficient of the complexes may not be solely depended on the extended π-conjugation but are reduced by molecular aggregation in the molecules.

[Orthodontic Management of the Impacted Mandibular Second Molar Tooth].

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Mah, Michael; Takada, Kenji

2016-09-01

When the mandibular permanent second molar becomes impacted, it is identified as a malocclusion that needs treatment as it often leads to unwanted complications such as caries and periodontitis of the adjacent permanent first molar. Other less common complications include root resorption of the adjacent first molar root or continued root development to be in close proximity to the inferior dental alveolar nerve. This paper seeks to differentiate various levels of severity of impaction and review treatment options that are considered clinically available for the proper management of the impacted mandibular permanent second molar. Treatment options that will be discussed in this article include timing of second molar removal for replacement by the third molar, relief of impaction via second premolar removal, surgical repositioning and the combination of third molar removal, surgical exposure and orthodontic uprighting of the impacted tooth. Depending on the severity of the impaction, most impactions can be easily and predictably corrected with nickel titanium archwires or auxillary open coil springs or uprighting springs. Uncommonly, the mandibular permanent second molar can become severely impacted and in close proximity to the inferior dentoalveolar nerve. In these instances, the use of temporary anchorage devices such as microimplants has shown to be successful in uprighting the severely impacted mandibular permanent second molars. © EDP Sciences, SFODF, 2016.

Epidemiological Status of Third Molars in an Iranian Population

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Mahnaz Sheikhi

2016-07-01

Full Text Available Background Impaction of third molars is a common phenomenon. The incidence of impacted third molars varies in different populations. Objectives The aim of this study is to assess radiographic status (root development degree, angulation, and eruption level of the third molar in Iranian population via panoramic radiographs. Patients and Methods 647 patients, ranging in age from 17 - 25, were selected from three regions of Iran. Based on their panoramic radiographs, their root development degree, angulation, and eruption levels were analyzed. Results The angulation of upper third molars were vertical (44.6%, distoangular (44.1%, mesioangular (10.7%, and horizontal (0.6%. For lower third molars, the angulation was mesioangular (44.5%, vertical (33.8%, distoangular (12.2%, and horizontal (9.5%. The eruption levels of maxillary third molars were C > A> B, and for mandibular third molars they were A > B> C. The order of root development prevalence of the maxillary and mandibular third molars was complete > 2/3 > 1/3. Conclusions The most common status of impaction of the third molars in the maxilla was vertical angulation, level C of eruption, and complete root formation. In the mandible it was mesioangular, level A of eruption, and complete root formation. Since the study sample consists of patients from the north, middle, and south of Iran, the sample can represent the whole population of Iran.

Root growth during molar eruption in extant great apes.

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Kelley, Jay; Dean, Christopher; Ross, Sasha

2009-01-01

While there is gradually accumulating knowledge about molar crown formation and the timing of molar eruption in extant great apes, very little is known about root formation during the eruption process. We measured mandibular first and second molar root lengths in extant great ape osteological specimens that died while either the first or second molars were in the process of erupting. For most specimens, teeth were removed so that root lengths could be measured directly. When this was not possible, roots were measured radiographically. We were particularly interested in the variation in the lengths of first molar roots near the point of gingival emergence, so specimens were divided into early, middle and late phases of eruption based on the number of cusps that showed protein staining, with one or two cusps stained equated with immediate post-gingival emergence. For first molars at this stage, Gorilla has the longest roots, followed by Pongo and Pan. Variation in first molar mesial root lengths at this stage in Gorilla and Pan, which comprise the largest samples, is relatively low and represents no more than a few months of growth in both taxa. Knowledge of root length at first molar emergence permits an assessment of the contribution of root growth toward differences between great apes and humans in the age at first molar emergence. Root growth makes up a greater percentage of the time between birth and first molar emergence in humans than it does in any of the great apes. Copyright (c) 2009 S. Karger AG, Basel.

One year Survival Rate of Ketac Molar versus Vitro Molar for Occlusoproximal ART Restorations: a RCT

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PACHECO Anna Luisa de Brito

2017-11-01

Full Text Available Abstract Good survival rates for single-surface Atraumatic Restorative Treatment (ART restorations have been reported, while multi-surface ART restorations have not shown similar results. The aim of this study was to evaluate the survival rate of occluso-proximal ART restorations using two different filling materials: Ketac Molar EasyMix (3M ESPE and Vitro Molar (DFL. A total of 117 primary molars with occluso-proximal caries lesions were selected in 4 to 8 years old children in Barueri city, Brazil. Only one tooth was selected per child. The subjetcs were randomly allocated in two groups according to the filling material. All treatments were performed following the ART premises and all restorations were evaluated after 2, 6 and 12 months. Restoration survival was evaluated using Kaplan-Meier survival analysis and Log-rank test, while Cox regression analysis was used for testing association with clinical factors (α = 5%. There was no difference in survival rate between the materials tested, (HR = 1.60, CI = 0.98–2.62, p = 0.058. The overall survival rate of restorations was 42.74% and the survival rate per group was Ketac Molar = 50,8% and Vitro Molar G2 = 34.5%. Cox regression test showed no association between the analyzed clinical variables and the success of the restorations. After 12 months evaluation, no difference in the survival rate of ART occluso-proximal restorations was found between tested materials.

Mandibular molar crown-topography, a biological predisposing ...

African Journals Online (AJOL)

Mandibular molar crown-topography, a biological predisposing factor to development of caries – a post-mortem analysis of 2500 extracted lower permanent molars at the dental centre, University of Benin teaching hospital.

Factors associated with complications of removal of third molars: a transversal study.

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Barbosa-Rebellato, Nelson-Luis; Thomé, Ana-Carolina; Costa-Maciel, Cássia; Oliveira, Jaina; Scariot, Rafaela

2011-05-01

The purpose of this study is to estimate the overall frequency of complications associated with third molars (M3) removal and to identify the risk factors associated with these complications. To the transversal analysis, a researcher confidentially reviewed the records of all M3 surgery patients. The predictor variables were demographic (i.e. age and gender), localization and position of third molar, bone removal and tooth sectioning. 210 patients had one or more third molars teeth removed, a total of 605 teeth. The sample's mean age was 21.6±9.2 years, with 1,4 woman to 1 man. Postoperative complications were recorded in 54 extractions of third molars. The most common complications were infection (42.6%), followed by radicular fractures (11.1%) and gingival alterations (11.1%). Complications were significantly affected by 3 factors: age over 25 years old (p=0.002--OR 2.21), location (p=0.006--OR 2.36), bone removal (p=0.002--OR 3.03) and tooth sectioning (p=0.00002--OR 3.59). The results of these analyses suggest that age, location of the tooth, bone removal and tooth sectioning appear to be associated with a higher complication rate for M3 extractions.

Morphometric evaluation of external root resorption of mandibular second molar teeth adjacent to the impacted third molars in CBCT imaging of Tehran\\'s population between 2011-2014

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Fatemeh Ezoddini Ardakani

2017-04-01

Full Text Available Introduction: Presence of external root resorption in second molars associated with impacted mandibular third molars was not rare. The neglect of this issue may leads to penetration of the pulp and loss of the second molars. The aim of this study was to investigate the incidence and risk factors affecting the external root resorption in second molars associated with mandibular impacted third molars were inclined mesially and horizontally by Cone Beam Computer Tomography (CBCT images. Methods: In this cross sectional study the samples consisted of 231 scans with mesially and horizontally impacted mandibular third molars. Incidence of external root resorption of second molars and the effects of age, gender and clinical parameters such as location and intensity of external root resorption were considered. Moreover, depth and inclination of impacted mandibular third molar were evaluated by CBCT. The data were analyzed by Chi-square test. Results: The overall incidence of external root resorption in the second molars was 22.08%. Incidence of external root resorption in second molars was significantly related to gender and inclination of third molar. The relations between external root resorption and impaction depth of third molar or the patient's age was not statistically significant. However, the relationship between external root resorption and the intensity or depth of impacted third molar and location of root resorption was statistically meaningful. Conclusion: Patient’s gender and horizontal inclination of third molars are the most important factors affecting the presence of external root resorption in the second molars associated with mesially and horizontally impacted mandibular third molars.

Clinician-related factors behind the decision to extract an asymptomatic lower third molar. A cross-sectional study based on Spanish and Portuguese dentists.

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Alves-Pereira, D; Pereira-Silva, D; Figueiredo, R; Gay-Escoda, C; Valmaseda-Castellón, E

2017-09-01

Scientific literature estimates that around 18 to 40 % of asymptomatic third molars are extracted. The aims of the present study were to determine the indications for extraction of asymptomatic lower third molars in a sample of Spanish and Portuguese dentists, and to relate these indications to the clinicians' training and professional experience. A survey consisting of 15 cases of asymptomatic lower third molars was emailed to Portuguese and Spanish dentists. The clinicians were asked to assess the level of difficulty of the extractions and to make a reasoned recommendation based on the panoramic radiographs, gender and age of the patients. 381 clinicians filled in the questionnaires. Most of the professionals had over 13 years of clinical experience. The number of Spanish clinicians with postgraduate degrees in Oral Surgery was significantly higher. On average, 42% of respondents recommended extraction of asymptomatic third molars. The indication for extraction was significantly higher among Portuguese dentists. Clinical experience was negatively correlated with the perceived extraction difficulty (pPortuguese dentists were more in favour of removing asymptomatic lower third molars than the Spanish dentists, although the latter had a higher proportion of professionals with postgraduate studies in Oral Surgery.

Predicting pathology in impacted mandibular third molars

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Aveek Mukherji

2017-01-01

Full Text Available Introduction: The rising incidence of the impacted mandibular third molars and their association with pathologies is now considered a public health problem. Aims and Objectives: The objective of this study was to assess the position of impacted mandibular third molars that are prone to developing pathologies and to determine the frequency and type of pathological conditions associated with these impacted teeth to facilitate planning for their prophylactic removal. Materials and Methods: Consecutive panoramic radiographs and clinical examination of 300 patients with impacted mandibular third molars were collected. They were segregated according to Pell and Gregory’s classification, Winter’s classification, and according to their state of eruption. These were correlated with associated pathologies based on clinical and radiological criteria. Statistical Analysis Used: Descriptive statistics included computation of percentages, mean, and standard deviations. The statistical test applied for the analysis was Pearson’s Chi-square test (χ2. For this test, confidence interval and P value were set at 93% and ≤0.03, respectively. Results: The pathology most commonly associated with impacted third molars was pericoronitis, which had the highest frequency of occurrence in partially erupted, distoangular, and IA positioned (as per Pell and Gregory classification impacted teeth. Impacted mandibular third molars, which were in IA position, placed mesially, and partially erupted, were prone to develop pathologies such as dental caries and periodontitis. Conclusion: The clinical and radiographical features of impacted third molar may be correlated to the development of their pathological complications. The partially impacted mandibular third molars with mesioangularly aligned in IA position have the highest potential to cause pathological complications.

Bilateral lower second molar impaction in teenagers: An emergent problem?

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Shinohara Elio

2010-01-01

Full Text Available The frequency of simultaneously impacted second and third molars in teenagers is increasing and becoming a common occurrence in adolescent oral surgery practice. The traditional treatment is the removal of the third molar by conventional access but repositioning of the surgical flap to the distal face of the first molar can predispose to complications such as pericoronitis and delayed healing of the attached gingiva. We present a case in which we use the germectomy approach to remove the impacted third molar for the eruption of the second molar through a vestibular incision. This incision offers excellent bone exposure and exit route for the third molar without disturbing the gingiva attached architecture on the distal face of the first molar providing good healing environment.

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients

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Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong [Chiang Mai University, Chiang Mai (Thailand)

2013-12-15

This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients

International Nuclear Information System (INIS)

Mahasantipiya, Phattaranant May; Pramojanee, Sakarat; Thaiupathump, Trasapong

2013-01-01

This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ≥15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. It might be possible to predict chronological age from the eruption height of the wisdom teeth.

Treatment of ectopic first permanent molar teeth.

Science.gov (United States)

Hennessy, Joe; Al-Awadhi, E A; Dwyer, Lian O; Leith, Rona

2012-11-01

Ectopic eruption of the first permanent molar is a relatively common occurence in the developing dentition. A range of treatment options are available to the clinician provided that diagnosis is made early. Non-treatment can result in premature exfoliation of the second primary molar, space loss and impaction of the second premolar. This paper will describe the management of ectopic first permanent molars, using clinical examples to illustrate the available treatment options. This paper is relevant to every general dental practitioner who treats patients in mixed dentition.

The prevalence of Molar Incisor Hypomineralisation (MIH) in a group of Italian school children.

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Calderara, P C; Gerthoux, P M; Mocarelli, P; Lukinmaa, P L; Tramacere, P L; Alaluusua, S

2005-06-01

This epidemiological study in a group of Italian children was undertaken in order to increase our knowledge of the prevalence of Molar Incisor Hypomineralisation (MIH) in different European countries. A population of school children aged 7.3 - 8.3 years, living in Lissone, Northern Italy, was examined for the presence and severity of MIH. Of a total of 227 children (113 females), 31 (13.7%) had MIH, the tooth prevalence in the permanent first molars being 5.8%. Fifteen children (6.6%) had demarcated opacities in the incisors with a tooth prevalence of 2.1%. The defects in the molars were mild with the exception of one child who had severe defects. MIH was quite common in this Italian town, and the prevalence figures were near those reported in Scandinavian countries but clearly higher than those from Dresden, Germany.

PULPOTOMIES WITH PORTLAND CEMENT IN HUMAN PRIMARY MOLARS

Science.gov (United States)

Conti, Taísa Regina; Sakai, Vivien Thiemy; Fornetti, Ana Paula Camolese; Moretti, Ana Beatriz Silveira; Oliveira, Thais Marchini; Lourenço, Natalino; Machado, Maria Aparecida Andrade Moreira; Abdo, Ruy Cesar Camargo

2009-01-01

Two clinical cases in which Portland cement (PC) was applied as a medicament after pulpotomy of mandibular primary molars in children are presented. Pulpotomy using PC was carried out in two mandibular first molars and one mandibular second molar, which were further followed-up. At the 3, 6 and 12-month follow-up appointments, clinical and radiographic examinations of the pulpotomized teeth and their periradicular area revealed that the treatments were successful in maintaining the teeth asymptomatic and preserving pulpal vitality. Additionally, the formation of a dentin bridge immediately below the PC could be observed in the three molars treated. PC may be considered as an effective alternative for primary molar pulpotomies, at least in a short-term period. Randomized clinical trials with human teeth are required in order to determine the suitability of PC before unlimited clinical use can be recommended. PMID:19148409

Treatment of ectopic first permanent molar teeth.

LENUS (Irish Health Repository)

Hennessy, Joe

2012-11-01

Ectopic eruption of the first permanent molar is a relatively common occurence in the developing dentition. A range of treatment options are available to the clinician provided that diagnosis is made early. Non-treatment can result in premature exfoliation of the second primary molar, space loss and impaction of the second premolar. This paper will describe the management of ectopic first permanent molars, using clinical examples to illustrate the available treatment options. CLINICAL RELEVANCE: This paper is relevant to every general dental practitioner who treats patients in mixed dentition.

Internal structure of mandible around mandibular molar using computed tomography. Anatomical consideration of molar anchorage in orthodontic treatment

International Nuclear Information System (INIS)

Enomoto, Yutaka; Yamashita, Daisuke; Saito, Katsuhiko; Kasai, Kazutaka

2008-01-01

For establishment of fine occlusion, facial profile and oral function in orthodontic treatment, molar anchorage in teeth movement is important manner in extracted cases. The aims of this study were to investigate the relationship between facial morphology and internal structure of mandibular body in molar region by computer tomography, and to discuss about molar anchorage in orthodontic treatment. The data for this study were obtained from 35 modern male Japanese skulls (mean age; 27 year-old, ranged from 18 year-old to 47 year-old). Measurement variables were FMA, SN to mandibular plane angle, gonial angle, alveolar breadth, cortical bone thickness of buccal and lingual sides, and the distance between dental root and cortical bone. As a result, alveolar breadth and the distance between dental root and cortical bone were narrow in long facial type, on the contrary, these variables were wide in short facial type. The result suggested that these variables were considered important factors as molar anchorage in extracted cases. (author)

Dental age estimation from the developmental stage of the third molars in western Chinese population.

Science.gov (United States)

Li, Guo; Ren, Jiayin; Zhao, Shuping; Liu, Yuanyuan; Li, Na; Wu, Wanhong; Yuan, Shanshan; Wang, Hu

2012-06-10

The purpose of this study is to provide reference data about estimating dental age from third molars of the western Chinese population for comparing with other populations and being applied to the age estimation of western Chinese juveniles and adolescents. A total of 2078 digital panoramic radiographs of 989 male and 1089 female Chinese subjects aged between 5 and 23 years were examined. The mineralization status of the third molars was assessed using the formation stages described by Demirjian et al. with two modifications. The results showed that the development of third molars in the western Chinese population was likely to begin at age 5 in both males and females. The third molars 28 and 48 showed significantly higher frequency in females than in males. The third molars 18 in the stage 1, 38 in the stages 1, A and G, and 48 in the stage H showed significantly older average age in females than in males. The Demirjian's stages C and D could be used as a reference stage to determine dichotomously whether a western Chinese is more likely to be under or above age 14 or 16, respectively. This study provided reference data for the age estimation of western Chinese juveniles and adolescents by the mineralization stages of the third molar. Apart from forensic age determination in living subjects, the presented reference data can also be used for age estimations of unidentified corpses and skeletons. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Actitud terapéutica ante sacos foliculares de terceros molares incluídos Therapeutic approach to impacted third molar follicles

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R. González García

2005-04-01

Full Text Available El quiste dentígero o folicular es un quiste odontogénico del desarrollo. Está revestido por el epitelio del folículo dentario, y suele estar en relación con un diente permanente incluído. Presentamos el caso clínico de un paciente en el que se observa la aparición de un quiste dentígero a partir del saco folicular de un tercer molar incluído no exodonciado, y lo comparamos con la evolución de un cordal incluído y su saco folicular contralaterales en los que se realizó la exodoncia. El tratamiento definitivo del quiste dentígero asociado a un tercer molar incluído es quirúrgico, con la exodoncia de la pieza y enucleación del quiste. Los sacos foliculares mayores de 2 mm asociados a terceros molares incluídos evolucionan en numerosas ocasiones a quistes foliculares. Está indicada la exodoncia de dichos cordales para evitar la evolución a quiste dentígero.The dentigerous cyst or follicular cyst is a developmental odontogenic cyst. It is covered by the epithelium of the dental follicle, and it tends to be related to an impacted permanent tooth. The case report of a patient who was seen to develop a dentigerous cyst arising from the follicle of an impacted non-extracted third molar is presented. This is then compared with the evolution of the contralateral impacted third molar and its follicle that was extracted. The definitive treatment for a dentigerous cyst associated with an impacted third molar is surgical, the extraction of the tooth and enucleation of the cyst. Follicles measuring more+ than 2 mm and that are associated with impacted third molars often develop into follicular cysts. The extraction of these third molars is indicated in order to avoid the development of a dentigerous cyst

Forensic age estimation based on magnetic resonance imaging of third molars: converting 2D staging into 3D staging.

Science.gov (United States)

De Tobel, Jannick; Hillewig, Elke; Verstraete, Koenraad

2017-03-01

Established methods to stage development of third molars for forensic age estimation are based on the evaluation of radiographs, which show a 2D projection. It has not been investigated whether these methods require any adjustments in order to apply them to stage third molars on magnetic resonance imaging (MRI), which shows 3D information. To prospectively study root stage assessment of third molars in age estimation using 3 Tesla MRI and to compare this with panoramic radiographs, in order to provide considerations for converting 2D staging into 3D staging and to determine the decisive root. All third molars were evaluated in 52 healthy participants aged 14-26 years using MRI in three planes. Three staging methods were investigated by two observers. In sixteen of the participants, MRI findings were compared with findings on panoramic radiographs. Decisive roots were palatal in upper third molars and distal in lower third molars. Fifty-seven per cent of upper third molars were not assessable on the radiograph, while 96.9% were on MRI. Upper third molars were more difficult to evaluate on radiographs than on MRI (p third molars were equally assessable on both imaging techniques (93.8% MRI, 98.4% radiograph), with no difference in level of difficulty (p = .375). Inter- and intra-observer agreement for evaluation was higher in MRI than in radiographs. In both imaging techniques lower third molars showed greater inter- and intra-observer agreement compared to upper third molars. MR images in the sagittal plane proved to be essential for staging. In age estimation, 3T MRI of third molars could be valuable. Some considerations are, however, necessary to transfer known staging methods to this 3D technique.

Higher glucocorticoid replacement doses are associated with increased mortality in patients with pituitary adenoma.

Science.gov (United States)

Hammarstrand, Casper; Ragnarsson, Oskar; Hallén, Tobias; Andersson, Eva; Skoglund, Thomas; Nilsson, Anna G; Johannsson, Gudmundur; Olsson, Daniel S

2017-09-01

Patients with secondary adrenal insufficiency (AI) have an excess mortality. The objective was to investigate the impact of the daily glucocorticoid replacement dose on mortality in patients with hypopituitarism due to non-functioning pituitary adenoma (NFPA). Patients with NFPA were followed between years 1997 and 2014 and cross-referenced with the National Swedish Death Register. Standardized mortality ratio (SMR) was calculated with the general population as reference and Cox-regression was used to analyse the mortality. The analysis included 392 patients (140 women) with NFPA. Mean ± s.d. age at diagnosis was 58.7 ± 14.6 years and mean follow-up was 12.7 ± 7.2 years. AI was present in 193 patients, receiving a mean daily hydrocortisone equivalent (HCeq) dose of 20 ± 6 mg. SMR (95% confidence interval (CI)) for patients with AI was similar to that for patients without, 0.88 (0.68-1.12) and 0.87 (0.63-1.18) respectively. SMR was higher for patients with a daily HCeq dose of >20 mg (1.42 (0.88-2.17)) than that in patients with a daily HCeq dose of 20 mg (0.71 (0.49-0.99)), P  = 0.017. In a Cox-regression analysis, a daily HCeq dose of >20 mg was independently associated with a higher mortality (HR: 1.88 (1.06-3.33)). Patients with daily HCeq doses of ≤20 mg had a mortality risk comparable to patients without glucocorticoid replacement and to the general population. Patients with NFPA and AI receiving more than 20 mg HCeq per day have an increased mortality. Our data also show that mortality in patients substituted with 20 mg HCeq per day or less is not increased. © 2017 European Society of Endocrinology.

Presence of third molars in orthodontic patients from northern Greece

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Barka G

2012-05-01

Full Text Available Georgia Barka,1 Georgios Tretiakov,1 Theodosios Theodosiou,2 Ioulia Ioannidou-Marathiotou31School of Dentistry, 2Biostatistics, Department of Informatics, School of Natural Sciences, 3Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, GreeceObjective: The purpose of the present study was to investigate the frequency of presence of third molar teeth and their distribution in each jaw and each side, according to sex, in a group of orthodontic patients with permanent dentition from northern Greece.Methods: The sample included panoramic radiographs from 220 patients with permanent dentition (mean age 13.62 ± 1.81. The Χ2 test was used to assess the relationships between the variables, and the Fisher's exact test was used in cases where the expected frequencies in each cell were <5.Results: The frequency of third molar presence was 79.1%, and 20.9% was the frequency of third molar agenesis. Intersexual differences in the number of third molars was not statistically significant. There was a correlation between the distribution of third molars on the right and the left side (Fisher's exact test = 100.788; P = 0. The two sides showed the same tendency toward the presence or absence of third molars. A correlation was also found between the distribution of maxillary and mandibular third molars (Fisher's exact test = 24.372; P = 0. In each jaw, the presence or absence of third molars was highly related to the number of third molars found in the other jaw.Conclusion: The present results showed that in this orthodontic group of northern Greek patients, presence accounted for 79.1% and agenesis for 20.9%. No significant difference was found between the frequencies of third molar presence on the left and right sides in either the maxilla or mandible.Keywords: third molars, presence, orthodontic population, Greeks

Molar Incisor Hypomineralisation

NARCIS (Netherlands)

Elfrink, M.; Weerheijm, K.L.

2013-01-01

Molar Incisor Hypomineralisation (mih) wordt omschreven als een hypomineralisatie (van systemische oorsprong) van één tot vier blijvende eerste molaren, vaak in combinatie met aangedane incisieven. mih-molaren zijn fragieler en cariësgevoeliger dan gewone molaren. Een kenmerk van mih-molaren is een

Molar Incisor Hypomineralisation

NARCIS (Netherlands)

Elfrink, M.; Weerheijm, K.L.

2009-01-01

Molar Incisor Hypomineralisation (MIH) wordt gedefinieerd als een hypomineralisatie van systemische oorsprong van één tot vier blijvende eerste molaren, vaak in combinatie met aangedane incisieven. MIH-molaren zijn fragieler en cariësgevoeliger dan gewone molaren. Een kenmerk van MIH-molaren is een

Molar Incisor Hypomineralisation

NARCIS (Netherlands)

Elfrink, M.; Weerheijm, K.

2011-01-01

Molar Incisor Hypomineralisation (mih ) wordt gedefinieerd als een hypomineralisatie van systemische oorsprong van één tot vier blijvende eerste molaren, vaak in combinatie met aangedane incisieven. mih -molaren zijn fragieler en cariësgevoeliger dan gewone molaren. Een kenmerk van mih -molaren is

The not-so-harmless maxillary primary first molar extraction.

Science.gov (United States)

Northway, W M

2000-12-01

Premature loss of primary molars has been associated with space loss and eruptive difficulties, especially when the loss occurs to the primary second molars and when it occurs early. This has not been thought to be the case for primary first molars. The author revisited 13 cases from an earlier study on the effects of premature loss of maxillary primary molars. These longitudinal cases were scrutinized, using serial panoramic radiographs, to explain the irregular response in terms of dental migration. The author presents two case reports. In the earlier study, the author used digitized study casts and the concept of D + E space--the space occupied by the primary first and second molars--to describe the dental migration that occurred after premature tooth loss. Using analysis of variance on data generated using an instrument capable of measuring in tenths of millimeters, the author produced findings regarding the amount of space loss, rate of space loss, effect of age at loss, amount of space regained at the time of replacement by the permanent tooth and effect on Angle's classification. Finally, the author created a simulation describing directional change; this revealed that the maxillary primary first molar loss resulted in a mesial displacement of the permanent canine during eruption. When the maxillary primary first molar is lost prematurely, the first premolar erupts in a more mesial direction than normal, as a result of the mesial incline of the primary second molar, and consumes the space of the permanent canine, which becomes blocked out. Rather than use a space maintainer after the premature loss of the maxillary primary first molar, the author suggests, clinicians can choose from a number of other options for preventing the first premolar from erupting too far in a mesial direction.

Liquid phase PVTx properties of (water + tert-butanol) binary mixtures at temperatures from 278.15 to 323.15 K and pressures from 0.1 to 100 MPa. II. Molar isothermal compressions, molar isobaric expansions, molar thermal pressure coefficients, and internal pressure

International Nuclear Information System (INIS)

Egorov, Gennadiy I.; Makarov, Dmitriy M.; Kolker, Arkadiy M.

2013-01-01

Highlights: ► Molar isothermal compressions and molar isobaric expansions were evaluated. ► Coefficients of thermal pressure and internal pressure were obtained. ► Concentration dependences of coefficients under study display extremes. ► Temperature and pressure dependences of internal pressure of the mixture were linear. -- Abstract: Molar isothermal compressions, molar isobaric expansions, molar coefficients of thermal pressure, and internal pressure were calculated over the whole concentration range of {water (1) + tert-butanol (2)} mixture at pressures from 0.1 to 100 MPa and temperatures from 278.15 to 323.15 K. It was revealed that the extremes, observed on concentration dependences of molar isothermal compression K T,m and molar isobaric expansion E P,m of the mixture, became more pronounced with pressure growth and temperature lowering. Values of molar thermal pressure coefficients of the mixture sharply rose at compositions with small TBA mole fraction and then decreased practically linearly with the alcohol content increasing. Temperature and pressure dependences of the mixture internal pressure were almost linear, and at low TBA concentrations changed significantly from the dependences of water, tert-butanol and their mixtures at large alcohol content

Standard molar enthalpy of formation of methoxyacetophenone isomers

International Nuclear Information System (INIS)

Amaral, Luísa M.P.F.; Morais, Victor M.F.; Ribeiro da Silva, Manuel A.V.

2014-01-01

Highlights: • Experimental and computational energetic study of methoxyacetophenone isomers. • Enthalpies of formation and phase transition determined by calorimetric techniques. • Quantum chemical calculations allowed estimation of enthalpies of formation. • Structure and energy correlations were established. - Abstract: Values of the standard (p o = 0.1 MPa) molar enthalpy of formation of 2′-, 3′- and 4′-methoxyacetophenones were derived from their standard molar energy of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpies of sublimation/vaporization of the compounds studied. The standard molar enthalpies of formation of the three compounds, in the gaseous phase, at T = 298.15 K, have been derived from the corresponding standard molar enthalpies of formation in the condensed phase and the standard molar enthalpies for the phase transition. The results obtained are −(232.0 ± 2.5), −(237.7 ± 2.7) and −(241.1 ± 2.1) kJ · mol −1 for 2′-, 3′- and 4′-methoxyacetophenone, respectively. Standard molar enthalpies of formation were also estimated from different methodologies: the Cox scheme as well as two different computational approaches using density functional theory-based B3LYP and the multilevel G3 methodologies

Angulation change of the third molar tooth in orthodontic treatment

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Ardiansyah S. Pawinru

2017-04-01

Full Text Available Objective : Impaction of the third molar tooth mandibular is often found in patients with orthodontic treatment. In orthodontic treatment, extraction cases of impaction of the third molar tooth are usually performed, but the patients often refuse this extraction. Extraction of premolar has a good effect on the third molar mandibular angulation during treatment. Material and Methods : This study is a retrospective clinical study with descriptive analytic to find out the effect of the first mandibular premolar tooth extraction to angulation change of the third molar mandibular in orthodontic treatment with a standard edgewise method. Angulation change was performed by comparing the third molar mandibular angulation before and after orthodontic treatment with panoramic radiographs. Angulation of the third molar tooth mandibular was calculated from the angle formed between the long axis of the tooth with the reference line infraorbita. Results : The sample comprised 60 of impacted mandibular third molar region of the left and right regions of 30 patients who had been treated declared cured in clinic of orthodontic specialist of Dentistry Faculty Padjadjaran University. The sample was divided into three (3 groups of patients before treatment angulation of the third molar tooth mandibular under 300, 300 to 600 and above 60o, then measured change of angulation and observed whether it increased, fixed or decreased. Results were analyzed by T- test and Wilcoxon test showed that there was a significant change in angulation of the third molar mandibular in orthodontic treatment with the first premolar tooth mandibular extraction. Conclusion : This study is that the first premolar tooth mandibular extraction affects the angulation of the third molar tooth mandibular after orthodontic treatment.

Using higher doses to compensate for tubing residuals in extended-infusion piperacillin-tazobactam.

Science.gov (United States)

Lam, Wendy J; Bhowmick, Tanaya; Gross, Alan; Vanschooneveld, Trevor C; Weinstein, Melvin P

2013-06-01

To mathematically assess drug losses due to infusion line residuals and evaluate methods to compensate for drug loss due to residual volumes in intravenous pump tubing. Literature was accessed through Ovid MEDLINE (1996-February 2013), using combinations of the search terms tubing residuals, residual volume, residual medication, intravenous infusions, intravenous injections, piperacillin, piperacillin-tazobactam, β-lactams, equipment design, infusion pumps, extended infusion, extended administration, and prolonged infusion. In addition, select reference citations from publications identified were reviewed. All articles that involved extended-infusion piperacillin-tazobactam implementation strategies were included in the review. Infusion pump characteristics and tubing residuals can affect extended-infusion piperacillin-tazobactam dosing strategies. Two studies addressing tubing residuals were identified. Both studies recommended increasing infusion volumes to compensate for tubing residuals. One study also recommended decreasing infusion-line dead space by using alternative infusion pump systems. Study calculations suggest that higher doses of piperacillin-tazobactam may be used to account for medication left in tubing residuals if alternative infusion pump systems cannot be obtained, and increased infusion volumes are not an option. Extended-infusion piperacillin-tazobactam has been used as a method of maximizing pharmacodynamic target attainment. Use of higher doses of piperacillin-tazobactam may be a reasonable method to compensate for drug loss due to residual volumes in large-bore intravenous pump tubing.

Rare occurrence of the left maxillary horizontal third molar impaction ...

African Journals Online (AJOL)

Rare occurrence of the left maxillary horizontal third molar impaction, the right maxillary third molar vertical impaction and the left mandibular third molar vertical impaction with inferior alveolar nerve proximity in a 30 year old female: a case report.

The contemporary management of third molars.

Science.gov (United States)

Hyam, D M

2018-03-01

The management of third molars requires a significant assessment and decision process both for the patient and the clinician. The clinician must always identify the indication for third molar surgery, assess the risks of the proposed procedure, and then modify their plan to account for the patient's current and future health, their social and financial setting, and the patient's tolerance of risk. In doing this, the clinician can tailor a solution to meet the individual patient's needs. This decision to remove a third molar is made in the fluid setting of the patient's quality of life and requires regular review. This article gives the clinician the tools, the matrix, and the confidence to guide patients through this process, and outlines some of the pitfalls and common points of bias within the process. © 2018 Australian Dental Association.

Accuracy in the legal age estimation according to the third molars mineralization among Mexicans and Columbians.

Science.gov (United States)

Costa, José; Montero, Javier; Serrano, Sarai; Albaladejo, Alberto; López-Valverde, Antonio; Bica, Isabel

2014-11-01

This study aims to assess the accuracy of age estimation according to two cut-off points of Demirjian's developmental stages (G and H) in the wisdom teeth, using panoramic radiographs from Colombian and Mexican teenagers. The degree of maturation of the third molars was classified according to Demirjian in 8 stages (from A to H) by a blinded trained assessor. The sensitivity, specificity and efficacy of two cut-off points (G and H) were calculated for both samples. The orthopantomographies of 316 subjects, 171 Colombians (54.1%) and 145 Mexicans (45.9%), were analyzed. The stage H was found to be the best threshold for detecting juveniles (because the high specificity) in all the third molars assessed. The specificity was higher for lower third molars than for upper third molars, but no asymmetrical discrepancy was noted. The stage H is the best cut-off point for detecting the adulthood when a high-specificity test is required. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

Prevalence of missing and impacted third molars in adults aged 25 years and above

Energy Technology Data Exchange (ETDEWEB)

Jung, Yun Hoa; Cho, Bong Hae [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yansan (Korea, Republic of)

2013-12-15

The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health.

Prevalence of missing and impacted third molars in adults aged 25 years and above

International Nuclear Information System (INIS)

Jung, Yun Hoa; Cho, Bong Hae

2013-01-01

The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health.

Cuartos molares supernumerarios: relato de caso clínico

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Daniela Nascimento Silva

2006-04-01

Full Text Available Los dientes supernumerarios se diagnostican mediante exámenes radiográficos de rutina, pues generalmente son asintomáticos. Los cuartos molares representan el segundo grupo de dientes supernumerarios con más frecuencias; ocurren en posición distal a los terceros molares, especialmente en el maxilar superior, y en la mayoría de casos, estos están incluidos. El objetivo de este artículo es realizar la presentación de un caso, de una mujer de 30 anos con los cuartos molares incluidos en el maxilar inferior y describir la técnica para su remoción.Supernumerary teeth are generally asymptomatic and are diagnosed by routine X-ray tests. The fourth molar teeth represent the second group of the most frequent supernumerary teeth, occur in distal position to the third molar teeth, specially in the superior maxilla and, in most of the cases, they are included. The aim of this paper is to comment on the case of a 30-year-old woman with the fourth molar teeth included in the inferior maxilla and to describe the technique used for their removal.

Impacted third molar transplantation on the malpracticed extraction socket.

Science.gov (United States)

Kim, Soung Min; Amponsah, Emmanuel K

2017-12-01

Autotransplantation with or without endodontic therapy is regarded as an alternative treatment option for the replacement of missing teeth. A primary responsibility of a maxillofacial surgeon is to reverse any malpractice to promote successful outcomes and improve the patient's quality of life. This paper presents a malpractice case of incorrect extraction of the lower second molar instead of the impacted third molar. A simple technique of transplanting the impacted third molar to the site of the extracted second molar is introduced by a maxillofacial specialist in Ghana. By making an intentional root socket and fixation without using additional appliances, a novel second molar was achieved with complete recovery. This patient was followed after transplant for a four-year period with the best satisfaction. A grant of the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea. (HI15C0689).

Bioavailibility of higher dose methotrexate comparing oral and subcutaneous route of administration in patients with rheumatoid arthritis

NARCIS (Netherlands)

Hoekstra, Monique; Hoekstra, M.; Haagsma, Cees; Neef, Cees; Proost, Johannes; van de Laar, Mart A F J; Knuif, Antonius

2004-01-01

OBJECTIVE: To determine the bioavailability of higher oral doses of methotrexate (MTX) in adult patients with rheumatoid arthritis (RA). METHODS: A pharmacokinetic analysis was performed in 15 patients with RA taking a stable dose of MTX (> or = 25 mg weekly). Separated by 2 weeks, a pharmacokinetic

Association of the Mandibular Third Molar Position to the Pericoronitis

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Tsvetan Tsvetanov

2018-02-01

Full Text Available Introduction: Pericoronitis is inflammation of the soft tissues surrounding the crown of a partially erupted tooth. Objective: To provide measurement of lower third molar angulation and determine relationship between mandibular third molar position and presence of pericoronitis. Material and methods: We studied 104 patients with lower third molar pericoronitis with clinical manifestations and measurement of lower third molar angulation. The mean age of patients was 25.7 years (range 18-35 years. Results: In this study was used the following statistical analysis, Pearson correlation coefficient and Spearman’s correlation coefficient (nonparametric version of the Pearson correlation coefficient for measure of the linear correlation between two variables - pericoronitis and angulation of the lower third molars. The chi-square test was used to assesses case incidences. The level of significance was p<0.05. 36.04% of partially impacted mandibular third molars were mesioangular followed by the vertical (25.47%, horizontal (18.97%, distoangular (9.21%, buccal (5.42% and lingual (3.79% position. The lowest part of the mandibular third molars is located in the ramus of mandible (1.08%. The present study was found in relation to mesioangular, distoangular, vertical impaction and pericoronitis (p<0.05. Conclusion: We conclude that the position of lower third molar may be able to be associated with presence of pericoronitis.

Estudio de volumen molar y refracción molar de miscelas de triglicéridos (triacetina, tributirina o tricaprilina y alcoholes (etanol, 1-butanol o 1-hexanol

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Rodríguez Rodríguez, M.

1992-12-01

Full Text Available Values of molar refraction for every studied mixtures show linear plots versus molar fractions of triglyceride. Values of molar volume show this behaviour, but only for tributyrin-butanol or tricaprylin-butanol miscellas. However, in tributyrin-ethanol mixtures, volume contractions have been found, whereas triacetin-butanol and tributyrin-hexanol show volume expansions. These facts are related to the mode of being structured of the alcohol and triglyceride molecules in mixtures. A linear relationship between molar volume and temperature have been found, and also a linear dependence between the coefficient of thermal expansion at constant pressure and the molar fraction of triglyceride.

Los valores de la refracción molar en todas las miscelas estudiadas presentan variaciones lineales frente a la fracción molar de triglicérido. la misma variación que presentan los valores del volumen molar de las miscelas tributirina y tricaprilina en butanol. Sin embargo, en las miscelas de tributirina-etanol se encuentran contracciones de volumen mientras que en las de triacetina-butanol y tributirina-hexanol expansiones, atribuidas en ambos casos a la forma de estructurarse las moléculas de alcohol y triglicérido en las miscelas. Por otra parte, se encuentra una variación lineal entre el volumen molar de las miscelas y la temperatura, y se establece una relación lineal entre el coeficiente de dilatación térmico molar a presión constante y la fracción molar de triglicérido en los cinco sistemas estudiados.

Elective extractions of first permanent molars: a review

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Melike Kiraz

2018-05-01

Full Text Available Permanent first molar teeth possess a key role in the setting-up of the occlusion, contribute significantly to the chewing function and serve as a guide for other teeth. However, it is frequently encountered that permanent first molar teeth are extracted due to the predicted negative prognoses of caries or developmental defects. As a result of the uncontrolled extraction of the permanent first molar teeth during the growth and development period, drifting of adjacent teeth, continued eruption of the opposing teeth and displacements can be seen. Furthermore, following one-sided extraction, midline deviations, oppositional tooth eruption, skeletal and dental asymmetry, unilateral chewing habits, and temporo-mandibular joint disorders may occur. To prevent these pathological conditions and to maintain the stability of the occlusal relation, it is necessary to do compensation and balancing extractions of the permanent first molar teeth on the opposite/symmetric arc, assuming mesial drag of the permanent second and third molar teeth. With such controlled-extractions, especially in Class I cases, orthodontic or prosthetic treatments, which may require extra time, cost and effort, could be prevented and a conceivable occlusion can be established.

Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia - A Retrospective Study of 3 Years.

Science.gov (United States)

Syed, Kamran Bokhari; Zaheer, Kamran Bokhari; Ibrahim, Mohammed; Bagi, Mustafa Abdel; Assiri, Mohammed Abdullah

2013-02-01

To report the prevalence of impacted third molars according to the age, gender and type among Saudi population. This retrospective study involved 3800 panoramic radiographs of subjects aged 18 to 45 years who presented to the College of Dentistry, King Khalid University, Abha, Kingdom of Saudi Arabia for oral care during the period from February 2009 to February 2011. Data collected was entered into a spreadsheet (Excel 2000; Microsoft, US) and analyzed using Statistical Package for Social Sciences (SPSS) version 16.0. A total of 713 impacted teeth were identified (18.76%) (p=0.003). The male to female ratio with impacted third molars was 604:109 (5.54:1) and the ratio of patients with impacted teeth was (5:1). Age group 1 (i.e., 20 to 25 years)had the highest prevalence of third molar tooth impaction (64.5%) and this decreased with increasing age. Incidence of tooth impaction is higher in the mandible than in maxilla. Males had a higher incidence of third molar impaction as compared to the females. Highest incidence is found in the age group of 20-25 years. Mesio-angular impaction was the most predominant type. How to cite this article: Syed KB, Kota Z, Ibrahim M, Bagi MA, Assiri MA. "Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia - A Retrospective Study of 3 Years". J Int Oral Health 2013; 5(1):43-47.

Prevalence of missing and impacted third molars in adults aged 25 years and above

Science.gov (United States)

Jung, Yun-Hoa

2013-01-01

Purpose The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. Results A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. Conclusion The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health. PMID:24380060

Pattern of third molar impaction in a Saudi population

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Ali H Hassan

2010-10-01

Full Text Available Ali H Hassan11Department of Preventive Dental Sciences, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi ArabiaObjective: To evaluate the current pattern of third molar impaction in a sample of Saudi patients.Methods: One thousand thirty-nine orthopantomograms (OPG of patients ranging in age from 19 to 46 years (536 males and 503 females were evaluated to determine the frequency of impacted third molars, their levels of eruption, and their angulations.Results: Four hundred twenty-two (40.5% of the 1039 OPG showed at least one impacted third molar, with no significant difference between males (222; 52.6% and females (200; 47.4% (P = 0.284. The most common number of impacted third molars per OPG was one (72.5%. Impacted third molars were 1.64 times more likely to occur in the mandible than in the maxilla. The most common angulation of impaction in the mandible was the mesial (33.4%, while the most common angulation in the maxilla, was the vertical (49.6%. Level B impaction was the most common in both maxilla (48.2% and mandible (67.7%. There was no significant difference in the frequency of impaction between the right and left sides in both jaws.Conclusion: The pattern of third molar impaction in the western region of Saudi Arabia is characterized by a high prevalence of impaction that is greater in the mandibles and with no sex predilection.Keywords: third molar, impaction, prevalence, Saudi 

Prevalence and morphometric analysis of three-rooted mandibular first molars in a Brazilian subpopulation

Science.gov (United States)

Rodrigues, Clarissa Teles; de Oliveira-Santos, Christiano; Bernardineli, Norberti; Duarte, Marco Antonio Hungaro; Bramante, Clovis Monteiro; Minotti-Bonfante, Paloma Gagliardi; Ordinola-Zapata, Ronald

2016-01-01

ABSTRACT The knowledge of the internal anatomy of three-rooted mandibular molars may help clinicians to diagnose and plan the root canal treatment in order to provide adequate therapy when this variation is present. Objectives: To determine the prevalence of three-rooted mandibular molars in a Brazilian population using cone beam computed tomography (CBCT) and to analyze the anatomy of mandibular first molars with three roots through micro-CT. Material and Methods: CBCT images of 116 patients were reviewed to determine the prevalence of three-rooted first mandibular molars in a Brazilian subpopulation. Furthermore, with the use of micro-CT, 55 extracted three-rooted mandibular first molars were scanned and reconstructed to assess root length, distance between canal orifices, apical diameter, Vertucci's classification, presence of apical delta, number of foramina and furcations, lateral and accessory canals. The distance between the orifice on the pulp chamber floor and the beginning of the curvature and the angle of canal curvature were analyzed in the distolingual root. Data were compared using the Kruskal-Wallis test (α=0.05). Results: The prevalence of three-rooted mandibular first molars was of 2.58%. Mesial roots showed complex distribution of the root canal system in comparison to the distal roots. The median of major diameters of mesiobuccal, mesiolingual and single mesial canals were: 0.34, 0.41 and 0.60 mm, respectively. The higher values of major diameters were found in the distobuccal canals (0.56 mm) and the lower diameters in the distolingual canals (0.29 mm). The lowest orifice distance was found between the mesial canals (MB-ML) and the highest distance between the distal root canals (DB-DL). Almost all distal roots had one root canal and one apical foramen with few accessory canals. Conclusions: Distolingual root generally has short length, severe curvature and a single root canal with low apical diameter. PMID:27812625

Some measurements of doses to patients from dental X-rays

International Nuclear Information System (INIS)

Woehni, T.

1976-01-01

Some measurements of doses to patients from conventional dental radiography and orthopantomography are presented. Doses to the red bone marrow are calculated. The bone marrow doses from two different exposures, Maxilla incisor and Molar bite-wing, were calculated to be 0.4 and 1.0 mrad respectively. The average dose to red bone marrow from a full-mouth examination (10 exposures) was 0.7 mrad/exposure. An orthopantomographic examination involved 2 mrad to the bone marrow. The greatest doses from an orthopantomographic examination were found around the lateral rotational axis, namely 700 mrad. The dose distributions from the two different cone lengths did not differ as much as expected, mainly due to scattered radiation. (Auth.)

Some measurements of doses to patients from dental X-rays

Energy Technology Data Exchange (ETDEWEB)

Woehni, T [Statens Institutt for Straalehygiene, Oslo (Norway)

1976-11-01

Some measurements of doses to patients from conventional dental radiography and orthopantomography are presented. Doses to the red bone marrow are calculated. The bone marrow doses from two different exposures, Maxilla incisor and Molar bite-wing, were calculated to be 0.4 and 1.0 mrad respectively. The average dose to red bone marrow from a full-mouth examination (10 exposures) was 0.7 mrad/exposure. An orthopantomographic examination involved 2 mrad to the bone marrow. The greatest doses from an orthopantomographic examination were found around the lateral rotational axis, namely 700 mrad. The dose distributions from the two different cone lengths did not differ as much as expected, mainly due to scattered radiation.

Cementoblastoma Relating to Right Mandibular Second Primary Molar

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Sivakumar Nuvvula

2016-01-01

Full Text Available Cementoblastoma is a benign lesion of the odontogenic ectomesenchymal origin. It rarely occurs in primary dentition. This report describes a case of a cementoblastoma relating to the right mandibular second primary molar in a 7-year-old girl. Her panoramic radiograph revealed a well-defined radiopaque lesion with a radiolucent border extending from the distal surface of the mandibular right first primary molar to the distal surface of mandibular second primary molar. The tumor was attached to the mesial root of primary second molar and was excised along with the teeth involved and sent for histopathological evaluation, which showed irregular trabeculae of mineralized tissue interspersed with fibrovascular connective tissue, trabeculae of mineralized tissue with prominent reversal lines, and peripheral rimming of the mineralized tissue with blast cells. On a six-month follow-up, there has been no recurrence of the lesion.

Incidence of cystic changes in impacted lower third molar

Directory of Open Access Journals (Sweden)

Shridevi R Adaki

2013-01-01

Full Text Available Objective: To assess the incidence of cystic changes in the impacted lower third molar (ILTM in which the pericoronal (follicular space is less than 2.5 mm as measured from the radiograph. The relationship between the cystic changes and patient′s age, sex, and angular position and contact of ILTM with adjacent tooth was also evaluated. Materials and Methods: Follicular space less than 2.5 mm as measured from the panoramic radiograph was included in the study. A total of 73 tissue samples collected during the extraction ILTM were examined histopathologically. Then the data were analyzed for associations with age, sex, angular position, and contact of the ILTM with an adjacent tooth. Results: There were 37 male and 36 female patients, age ranging from 17 to 35 years (mean 23.95 years. Out of 73 specimens, 17 (23.3% showed cystic changes; among them 16 (22.1% showed dentigerous cysts and 1 (1.2% showed odontogenic keratocysts. Most of the cystic changes occurred in the 26-30 year age range. The cystic changes showed male predominance but could not gain statistical significance. The relationship between cystic changes and angular position was statistically significant (P < 0.05. Higher probability was found in distoangular positioned ILTM. The relationship between cystic changes and communication of ILTM with the second molar was not statistically significant. Conclusion: Incidence of cystic changes in ILTM justifies extraction of the impacted tooth associated with symptoms. The decision to extract or not to extract impacted third molar should be individualized, rather than generalized.

Biophysical dose measurement using electron paramagnetic resonance in rodent teeth

International Nuclear Information System (INIS)

Khan, R.F.H.; Rink, W.J.; Boreham, D.R.

2003-01-01

Electron paramagnetic resonance (EPR) dosimetry of human tooth enamel has been widely used in measuring radiation doses in various scenarios. However, there are situations that do not involve a human victim (e.g. tests for suspected environmental overexposures, measurements of doses to experimental animals in radiation biology research, or chronology of archaeological deposits). For such cases we have developed an EPR dosimetry technique making use of enamel of teeth extracted from mice. Tooth enamel from both previously irradiated and unirradiated mice was extracted and cleaned by processing in supersaturated KOH aqueous solution. Teeth from mice with no previous irradiation history exhibited a linear EPR response to the dose in the range from 0.8 to 5.5 Gy. The EPR dose reconstruction for a preliminarily irradiated batch resulted in the radiation dose of (1.4±0.2) Gy, which was in a good agreement with the estimated exposure of the teeth. The sensitivity of the EPR response of mouse enamel to gamma radiation was found to be half of that of human tooth enamel. The dosimetric EPR signal of mouse enamel is stable up at least to 42 days after exposure to radiation. Dose reconstruction was only possible with the enamel extracted from molars and premolars and could not be performed with incisors. Electron micrographs showed structural variations in the incisor enamel, possibly explaining the large interfering signal in the non-molar teeth

Experimental and predicted data of excess molar enthalpies and excess molar volumes for the ternary system (1,3-dichlorobenzene + benzene + 1-chlorohexane) at T = 298.15 K

International Nuclear Information System (INIS)

Mato, Marta M.; Verdes, Pedro V.; Paz Andrade, M.I.; Legido, José Luis

2014-01-01

Graphical abstract: - Highlights: • Experimental enthalpy and densitiy for the mixture 1,3-dichlorobenzene + benzene + 1-chlorohexane were measured. • The excess molar volumes were calculated from the densities of the pure liquids and their mixtures. • The Cibulka equation was used to correlate the ternary contribution of the excess molar properties. • The experimental data were used to test several empirical equations. - Abstract: Experimental excess molar enthalpies, densities and excess molar volumes for the ternary system {x 1 1,3-dichlorobenzene + x 2 benzene + (1 − x 1 − x 2 ) 1-chlorohexane} have been determined at the temperature of 298.15 K and atmospheric pressure. Values of excess molar enthalpies were measured using a Calvet microcalorimeter, and excess molar volumes were determined from the densities of the pure liquids and mixtures, using a vibrating-tube densimeter. The results were fitted by means of different variable degree polynomials. Smooth representations of the results are presented and used to construct constant contours of excess molar enthalpy and excess molar volume on Roozeboom diagrams. Several empirical expressions that have been suggested for use with parameters and predicting excess properties of ternary mixtures from the experimental binary data were tested

Genetic integration of molar cusp size variation in baboons.

Science.gov (United States)

Koh, Christina; Bates, Elizabeth; Broughton, Elizabeth; Do, Nicholas T; Fletcher, Zachary; Mahaney, Michael C; Hlusko, Leslea J

2010-06-01

Many studies of primate diversity and evolution rely on dental morphology for insight into diet, behavior, and phylogenetic relationships. Consequently, variation in molar cusp size has increasingly become a phenotype of interest. In 2007 we published a quantitative genetic analysis of mandibular molar cusp size variation in baboons. Those results provided more questions than answers, as the pattern of genetic integration did not fit predictions from odontogenesis. To follow up, we expanded our study to include data from the maxillary molar cusps. Here we report on these later analyses, as well as inter-arch comparisons with the mandibular data. We analyzed variation in two-dimensional maxillary molar cusp size using data collected from a captive pedigreed breeding colony of baboons, Papio hamadryas, housed at the Southwest National Primate Research Center. These analyses show that variation in maxillary molar cusp size is heritable and sexually dimorphic. We also estimated additive genetic correlations between cusps on the same crown, homologous cusps along the tooth row, and maxillary and mandibular cusps. The pattern for maxillary molars yields genetic correlations of one between the paracone-metacone and protocone-hypocone. Bivariate analyses of cuspal homologues on adjacent teeth yield correlations that are high or not significantly different from one. Between dental arcades, the nonoccluding cusps consistently yield high genetic correlations, especially the metaconid-paracone and metaconid-metacone. This pattern of genetic correlation does not immediately accord with the pattern of development and/or calcification, however these results do follow predictions that can be made from the evolutionary history of the tribosphenic molar. Copyright 2009 Wiley-Liss, Inc.

Effects of a higher dose of near-infrared light on clinical signs and neuroprotection in a monkey model of Parkinson's disease.

Science.gov (United States)

Moro, Cécile; El Massri, Nabil; Darlot, Fannie; Torres, Napoleon; Chabrol, Claude; Agay, Diane; Auboiroux, Vincent; Johnstone, Daniel M; Stone, Jonathan; Mitrofanis, John; Benabid, Alim-Louis

2016-10-01

We have reported previously that intracranial application of near-infrared light (NIr) - when delivered at the lower doses of 25J and 35J - reduces clinical signs and offers neuroprotection in a subacute MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) monkey model of Parkinson's disease. In this study, we explored whether a higher NIr dose (125J) generated beneficial effects in the same MPTP monkey model (n=15). We implanted an NIr (670nm) optical fibre device within a midline region of the midbrain in macaque monkeys, close to the substantia nigra of both sides. MPTP injections (1.8-2.1mg/kg) were made over a five day period, during which time the NIr device was turned on and left on continuously throughout the ensuing three week survival period. Monkeys were evaluated clinically and their brains processed for immunohistochemistry and stereology. Our results showed that the higher NIr dose did not have any toxic impact on cells at the midbrain implant site. Further, this NIr dose resulted in a higher number of nigral tyrosine hydroxylase immunoreactive cells when compared to the MPTP group. However, the higher NIr dose monkeys showed little evidence for an increase in mean clinical score, number of nigral Nissl-stained cells and density of striatal tyrosine hydroxylase terminations. In summary, the higher NIr dose of 125J was not as beneficial to MPTP-treated monkeys as compared to the lower doses of 25J and 35J, boding well for strategies of NIr dose delivery and device energy consumption in a future clinical trial. Copyright © 2016 Elsevier B.V. All rights reserved.

Autologous Platelet-rich Plasma after Third Molar Surgery.

Science.gov (United States)

Gandevivala, Adil; Sangle, Amit; Shah, Dinesh; Tejnani, Avneesh; Sayyed, Aatif; Khutwad, Gaurav; Patel, Arpit Arunbhai

2017-01-01

The aim of this study is to compare the efficacy of autologous platelet-rich plasma (PRP) in the third molar impactions, with respect to: pain, swelling, healing, and periodontal status distal to the second molar in patients who need surgical removal of bilateral impacted mandibular third molars. Twenty-five patients of both sexes aged between 16 and 60 years who required bilateral surgical removal of their impacted third molars and met the inclusion criteria were included in the study. After surgical extraction of the third molar, primary closure was performed in the control group, whereas PRP was placed in the socket followed by primary closure in the case group. The outcome variables were pain, swelling, wound healing, and periodontal probe depth that were follow-up period of 2 months. Quantitative data are presented as mean. Statistical significance was checked by t -test. There was a difference in the pain (0.071) and facial swelling (0.184), reduction between test and control on day 3, but it was not found to be significant. Periodontal pocket depth (0.001) and wound healing (0.001) less in case group compared with the control group was found to be significant. The use of PRP lessens the severity of immediate postoperative sequelae and decreases preoperative pocket depth.

Changes in heart rate during third molar surgery

NARCIS (Netherlands)

Hollander, M. H. J.; Schortinghuis, J.; Vissink, A.

2016-01-01

Anxiety is an undesirable psychological phenomenon. Patients are usually anxious when subjected to third molar surgery, but the pattern of anxiety is unknown. The aim of this study was to assess the intensity and course of anxiety during third molar surgery. This study included 48 consecutive

Unusal canal configuration in maxillary and mandibular second molars

Directory of Open Access Journals (Sweden)

Ramachandran Ragunathan

2016-01-01

Full Text Available This clinical article describes three different case reports of maxillary and mandibular second molars with the unusual anatomy of single root with a single canal and their endodontic management. An unusual case of bilateralism is observed in the first two cases in the form of single-rooted second mandibular molars in both the quadrant of the same patient. The presence of maxillary second molar with single root and single canal in the third case is unusual.

Three-dimensional space changes after premature loss of a maxillary primary first molar.

Science.gov (United States)

Park, Kitae; Jung, Da-Woon; Kim, Ji-Yeon

2009-11-01

A space maintainer is generally preferred when a primary first molar is lost before or during active eruption of the first permanent molars in order to prevent space loss. However, controversy prevails regarding the space loss after eruption of the permanent first molars. The purpose of this study was to examine spatial changes subsequent to premature loss of a maxillary primary first molar after the eruption of the permanent first molars. Thirteen children, five girls and eight boys, expecting premature extraction of a maxillary primary first molar because of caries and/or failed pulp therapy, were selected. Spatial changes were investigated using a three-dimensional laser scanner by comparing the primary molar space, arch width, arch length, and arch perimeter before and after the extraction of a maxillary primary first molar. Also, the inclination and angulation changes in the maxillary primary canines, primary second molars, and permanent first molars adjacent to the extraction site were investigated before and after the extraction of the maxillary primary first molar in order to examine the source of space loss. There was no statistically significant space loss on the extraction side compared to the control side (P = 0.33). No consistent findings were seen on the inclination and angulation changes on the extraction side. The premature loss of a maxillary primary first molar, in cases with class I molar relationship, has limited influence on the space in permanent dentition.

Fracture behavior of human molars.

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Keown, Amanda J; Lee, James J-W; Bush, Mark B

2012-12-01

Despite the durability of human teeth, which are able to withstand repeated loading while maintaining form and function, they are still susceptible to fracture. We focus here on longitudinal fracture in molar teeth-channel-like cracks that run along the enamel sidewall of the tooth between the gum line (cemento-enamel junction-CEJ) and the occlusal surface. Such fractures can often be painful and necessitate costly restorative work. The following study describes fracture experiments made on molar teeth of humans in which the molars are placed under axial compressive load using a hard indenting plate in order to induce longitudinal cracks in the enamel. Observed damage modes include fractures originating in the occlusal region ('radial-median cracks') and fractures emanating from the margin of the enamel in the region of the CEJ ('margin cracks'), as well as 'spalling' of enamel (the linking of longitudinal cracks). The loading conditions that govern fracture behavior in enamel are reported and observations made of the evolution of fracture as the load is increased. Relatively low loads were required to induce observable crack initiation-approximately 100 N for radial-median cracks and 200 N for margin cracks-both of which are less than the reported maximum biting force on a single molar tooth of several hundred Newtons. Unstable crack growth was observed to take place soon after and occurred at loads lower than those calculated by the current fracture models. Multiple cracks were observed on a single cusp, their interactions influencing crack growth behavior. The majority of the teeth tested in this study were noted to exhibit margin cracks prior to compression testing, which were apparently formed during the functional lifetime of the tooth. Such teeth were still able to withstand additional loading prior to catastrophic fracture, highlighting the remarkable damage containment capabilities of the natural tooth structure.

Ruptured tubal molar pregnancy

African Journals Online (AJOL)

2011-05-19

May 19, 2011 ... In most instances, moles develop within the uterine cavity, but may occur at ... Patients with tubal molar pregnancy are very difficult to distinguish .... There was a left-sided adnexal mass, whose size could not be appreciated ...

Taurodont molars: Review of literature and radiological features

International Nuclear Information System (INIS)

Saini, T.; Wilson, C. A.

1990-01-01

Taurodontic molar teeth are present as a clinical entity in modem man. This is a suggestion that the occurrence has a racial bias. The importance of the differential diagnosis of teeth with enlarged pulp is discussed, and the possible influence of taurodontic molars on treatment planning is outlined. (author)

Excess molar volumes and isentropic compressibilities of binary

Indian Academy of Sciences (India)

Excess molar volumes (E) and deviation in isentropic compressibilities (s) have been investigated from the density and speed of sound measurements of six binary liquid mixtures containing -alkanes over the entire range of composition at 298.15 K. Excess molar volume exhibits inversion in sign in one binary ...

Radiographic evaluation of third molar development in 6 to 24 year olds

International Nuclear Information System (INIS)

Jung, Yun Hwa; Cho, Bong Hae

2014-01-01

This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females.

Dose area product measurement for diagnostic reference levels and analysis of patient dose in dental radiography

International Nuclear Information System (INIS)

Han, S.; Lee, B.; Shin, G.; Choi, J.; Kim, J.; Park, C.; Park, H.; Lee, K.; Kim, Y.

2008-01-01

In this study, diagnostic reference levels (DRLs) were suggested and patient doses were analysed through the dose-area product value in dental radiography. In intraoral radiography, at three sites, i.e. molar, premolar and incisor on the maxilla and acquired third quartile values: 55.5, 46 and 36.5 mGy cm 2 , respectively, were measured. In panoramic, cephalo-metric and cone beam computed tomography, the values were 120.3, 146 and 3203 mGy cm 2 (16 x 18 cm), respectively. It has been shown that, in intraoral radiography, the patient dose changes proportionally to the value of mA s, but the change in extra-oral radiography in response to mA s could not be confirmed. The authors could confirm, however, the difference in dose according to the manufacturer in all dental radiography examinations, except for panoramic radiography. Depending on the size of hospital, there were some differences in patient dose in intraoral radiography, but no difference in patient dose in extra-oral radiography. (authors)

Comparison of the Effects of Topical Ketamine and Tramadol on Postoperative Pain After Mandibular Molar Extraction.

Science.gov (United States)

Gönül, Onur; Satilmiş, Tülin; Ciftci, Alanur; Sipahi, Aysegül; Garip, Hasan; Göker, Kamil

2015-11-01

This study compared the analgesic efficacy of postoperative tramadol versus ketamine for preventing pain after mandibular molar extraction. Ninety patients who had undergone molar extraction were randomly divided into 3 groups: group T (tramadol 1 mg/kg), group K (ketamine 0.5 mg/kg), and group P (saline 2 mL). The treatment was applied to the extraction sockets using resorbable gelatin sponges. Pain after extraction was evaluated using a visual analog scale (VAS) 0.5, 1, 2, 4, 6, 12, 24, and 48 hours postoperatively. The VAS scores after extraction were statistically higher in group P than in either treatment group. Group K had the lowest pain intensity. This study shows that topical tramadol and ketamine are effective alternatives for decreasing pain after molar extractions. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Effect of premature loss of deciduous canines and molars on malocclusion of the permanent dentition.

Science.gov (United States)

Miyamoto, W; Chung, C S; Yee, P K

1976-01-01

The effect of the premature loss of deciduous canines and first and second molars on malocclusion of the permanent dentition was studied in 255 schoolchildren 11 years of age or older at the most recent examination of the permanent dentition. Malocclusion was evaluated by scoring malalignment (major and minor) and measurement of crowding in the anterior teeth. Children who had a premature loss of one or more canines or molars had a higher frequency of receiving orthodontic treatment of one type or another for the permanent dentition. The likelihood of need of treatment increased with the number of prematurely lost teeth. Children who had lost one or more deciduous teeth through age 9 had a greater than threefold increase in the frequency of orthodontic treatment relative to the control. Of those who did not receive orthodontic treatment, there was no detectable relationship of the premature loss of canines with the malalignment of permanent teeth. However, there was a significant effect of the premature extraction of molars on malalignment especially major malalignment of permanent teeth. No differences were noted in their effects between the first and second deciduous molars. Crowding of the anterior teeth was directly affected by the premature loss of deciduous canines.

Prevention of alveolar osteitis after third molar surgery: Comparative ...

African Journals Online (AJOL)

Prevention of alveolar osteitis after third molar surgery: Comparative study of the ... for surgical extraction of lower third molar were prospectively, consecutively, and ... Information on demographic, types and level of impaction, indications for ...

A study of the eruption of the mandibular first permanent molar

OpenAIRE

河野, 美砂子; Kohno, Misako

1995-01-01

The object of this study was to know what positional changes of the mandibular first permanent molars occur just before their gingival emergence. The eruptive process of the mandibular first molars was investigated during the period from alveolareruption to preoraleruption. The subjects were 14 patients whose second primary molars were prematurely lost in one side and remained on the other side. Longitudinal oblique cephalograms were used to estimate the eruptive process of the first molars o...

A single dose of oxytocin nasal spray improves higher-order social cognition in schizophrenia.

Science.gov (United States)

Guastella, Adam J; Ward, Philip B; Hickie, Ian B; Shahrestani, Sara; Hodge, Marie Antoinette Redoblado; Scott, Elizabeth M; Langdon, Robyn

2015-11-01

Schizophrenia is associated with significant impairments in both higher and lower order social cognitive performance and these impairments contribute to poor social functioning. People with schizophrenia report poor social functioning to be one of their greatest unmet treatment needs. Recent studies have suggested the potential of oxytocin as such a treatment, but mixed results render it uncertain what aspects of social cognition are improved by oxytocin and, subsequently, how oxytocin might best be applied as a therapeutic. The aim of this study was to determine whether a single dose of oxytocin improved higher-order and lower-order social cognition performance for patients with schizophrenia across a well-established battery of social cognition tests. Twenty-one male patients received both a single dose of oxytocin nasal spray (24IU) and a placebo, two weeks apart in a randomized within-subjects placebo controlled design. Following each administration, participants completed the social cognition tasks, as well as a test of general neurocognition. Results revealed that oxytocin particularly enhanced performance on higher order social cognition tasks, with no effects on general neurocognition. Results for individual tasks showed most improvement on tests measuring appreciation of indirect hints and recognition of social faux pas. These results suggest that oxytocin, if combined to enhance social cognition learning, may be beneficial when targeted at higher order social cognition domains. This study also suggests that these higher order tasks, which assess social cognitive processing in a social communication context, may provide useful markers of response to oxytocin in schizophrenia. Copyright © 2015 Elsevier B.V. All rights reserved.

Excess molar enthalpies for binary mixtures of different amines with water

International Nuclear Information System (INIS)

Zhang, Ruilei; Chen, Jian; Mi, Jianguo

2015-01-01

Highlights: • Isothermal excess molar enthalpies for binary mixtures of different amines with water. • The Redlich–Kister equation and the NRTL model was used to fit the experimental data. • The excess molar enthalpies were discussed with different structures of amines. - Abstract: The isothermal excess molar enthalpies for binary mixtures of different amines with water were measured with a C-80 Setaram calorimeter. The experimental results indicate that the excess molar enthalpy is related to the molecular structure. The experimental excess molar enthalpies were satisfactorily fitted with the Redlich–Kister equation. They were also used to test the suitability of the NRTL model, and the deviations are a little larger than the R–K equation

Root canal morphology of primary molars: a micro-computed tomography study.

Science.gov (United States)

Fumes, A C; Sousa-Neto, M D; Leoni, G B; Versiani, M A; da Silva, L A B; da Silva, R A B; Consolaro, A

2014-10-01

This was to investigate the root canal morphology of primary molar teeth using micro-computed tomography. Primary maxillary (n = 20) and mandibular (n = 20) molars were scanned at a resolution of 16.7 μm and analysed regarding the number, location, volume, area, structured model index (SMI), area, roundness, diameters, and length of canals, as well as the thickness of dentine in the apical third. Data were statistically compared by using paired-sample t test, independent sample t test, and one-way analysis of variance with significance level set as 5%. Overall, no statistical differences were found between the canals with respect to length, SMI, dentine thickness, area, roundness, and diameter (p > 0.05). A double canal system was observed in the mesial and mesio-buccal roots of the mandibular and maxillary molars, respectively. The thickness in the internal aspect of the roots was lower than in the external aspect. Cross-sectional evaluation of the roots in the apical third showed flat-shaped canals in the mandibular molars and ribbon- and oval-shaped canals in the maxillary molars. External and internal anatomy of the primary first molars closely resemble the primary second molars. The reported data may help clinicians to obtain a thorough understanding of the morphological variations of root canals in primary molars to overcome problems related to shaping and cleaning procedures, allowing appropriate management strategies for root canal treatment.

Apparent molar volumes and compressibilities of selected electrolytes in dimethylsulfoxide

International Nuclear Information System (INIS)

Warminska, Dorota; Grzybkowski, Waclaw

2010-01-01

Densities at T = (293.15, 298.15, 303.15, 313.15, 323.15, and 333.15) K and sound velocities at T = 298.15 K of tetraphenylphosphonium bromide, sodium tetraphenylborate, sodium bromide, and sodium perchlorate in dimethylsulfoxide have been measured over the composition range from (0 to 0.3) mol . kg -1 . From these data, apparent molar volumes and apparent molar isentropic compressibilities at infinite dilution as well as the expansibilities have been evaluated. The results have been discussed in terms of employing tetraphenylphosphonium tetraphenylborate as a reference electrolyte in splitting the limiting apparent molar volumes and apparent molar isentropic compressibilities into ionic contributions.

Radiographic evaluation of third molar development in 6- to 24-year-olds

Science.gov (United States)

Jung, Yun-Hoa

2014-01-01

Purpose This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. Materials and Methods A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. Results The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. Conclusion The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females. PMID:25279338

The origin of the lower fourth molar in canids, inferred by individual variation

Directory of Open Access Journals (Sweden)

Masakazu Asahara

2016-11-01

Full Text Available Background An increase in tooth number is an exception during mammalian evolution. The acquisition of the lower fourth molar in the bat-eared fox (Otocyon megalotis, Canidae, Carnivora, Mammalia is one example; however, its developmental origin is not clear. In some canids (Canidae, individual variation exist as supernumerary molar M4. This study focuses on the acquisition of the lower fourth molar in canids and proposes that the inhibitory cascade model can explain its origin. Methods Occlusal view projected area of lower molars was determined from 740 mandibles obtained from Canis latrans, Nyctereutes procyonoides, and Urocyon cinereoargenteus museum specimens. For each molar, relative sizes of molars (M2/M1 and M3/M1 scores affected by inhibition/activation dynamics during development, were compared between individuals with and without supernumerary molar (M4. Results Possession of a supernumerary molar was associated with significantly larger M2/M1 score in Canis latrans, M3/M1 score in Nyctereutes procyonoides, and M2/M1 and M3/M1 scores in Urocyon cinereoargenteus compared to individuals of these species that lacked supernumerary molars. Discussion We propose that, in canids, the supernumerary fourth molar is attributable to reduced inhibition and greater activation during molar development. In the bat-eared fox, altered inhibition and activation dynamics of dental development during omnivorous-insectivorous adaptation may be a contributing factor in the origin of the lower fourth molar.

Morphometric variation of extant platyrrhine molars: taxonomic implications for fossil platyrrhines

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Mónica Nova Delgado

2016-05-01

Full Text Available The phylogenetic position of many fossil platyrrhines with respect to extant ones is not yet clear. Two main hypotheses have been proposed: the layered or successive radiations hypothesis suggests that Patagonian fossils are Middle Miocene stem platyrrhines lacking modern descendants, whereas the long lineage hypothesis argues for an evolutionary continuity of all fossil platyrrhines with the extant ones. Our geometric morphometric analysis of a 15 landmark-based configuration of platyrrhines’ first and second lower molars suggest that morphological stasis may explain the reduced molar shape variation observed. Platyrrhine lower molar shape might be a primitive retention of the ancestral state affected by strong ecological constraints throughout the radiation of the main platyrrhine families. The Patagonian fossil specimens showed two distinct morphological patterns of lower molars, Callicebus—like and Saguinus—like, which might be the precursors of the extant forms, whereas the Middle Miocene specimens, though showing morphological resemblances with the Patagonian fossils, also displayed new, derived molar patterns, Alouatta—like and Pitheciinae—like, thereby suggesting that despite the overall morphological stasis of molars, phenotypic diversification of molar shape was already settled during the Middle Miocene.

Detection of Mesiobuccal Canal in Maxillary Molars and Distolingual Canal in Mandibular Molars by Dental CT: A Retrospective Study of 100 Cases

Directory of Open Access Journals (Sweden)

Sushma Rathi

2010-01-01

Full Text Available Objective. To detect presence of MB2 canal in maxillary molars and distolingual canal in mandibular molars by Dental CT. Material and Methods. A retrospective study of 100 Dental CTs was done. Axial and paraxial images obtained were used to assess the presence of MB2 canal in maxillary molars and distolingual canal in mandibular molars. Results. The youngest patient was of 11 years while the eldest patient was of 77 years. Males were 58 in number and females were 42 in number. MB2 canals were present in 57 patients and distolingual canal was present in 18 patients. Maximum MB2 canals were present in age group between 51 and 60 years, while distolingual canals were present in age group of 21–30 years. Conclusion. Dental CT allows adequate visualization of variation in root canal morphology and can be important diagnostic tool for successful endodontic therapy.

Effectiveness of various sterilization methods of contaminated post-fitted molar band

Directory of Open Access Journals (Sweden)

Anggia Tridianti

2013-06-01

Full Text Available Background: Molar band as anchoring device may be contaminated during the fitting process. Thus, decontamination process is essential to prevent cross-infection between patients. Purpose: The objective of this research was to determine the amount of bacteria in molar band post-fitted on the patient teeth, after previously undergone pre-sterilization using alcohol and ultrasonic cleaning bath followed by sterilization using dry heat oven and steam autoclave, in order to find the best method in decontamination of post-fitted molar band. Methods: Four molar bands which already fitted on one patient then divided evenly into two groups. The first group was pre-sterilized using alcohol. One of the bands then sterilized using dry heat oven, while the other one was sterilized using steam autoclave. The second group was pre-sterilized using ultrasonic cleaning bath. One band from this group then sterilized using dry heat oven and the other was sterilized using steam autoclave. The next step was to immerse all the bands in a phosphate-buffered saline solution. Using micropipette, the solution was retrieved and dropped upon a petri dish containing Brain Heart Infusion broth. The dish was then stored in an incubator for 24 hours, prior to counting the number of bacteria existed. The same methods were used to the rest of the patients, with total 128 molar bands from 32 patients. Results: There was a profound difference in numbers of bacteria found between those methods of sterilization. However, there was a non significant difference between the two groups which were at the alcohol-steam autoclave group and at the ultrasonic cleaning bath-steam autoclave group. Conclusion: This study showed that steam autoclave is better than for sterilizing molar band, as it left the minimal amount of bacteria in post-fitted molar band.Latar belakang: Molar band merupakan suatu alat penjangkaran yang dapat mengalami kontaminasi selama proses fitting band, sehingga perlu

Orthodontic space closure after first molar extraction without skeletal anchorage.

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Jacobs, Collin; Jacobs-Müller, Claudia; Luley, Carolin; Erbe, Christina; Wehrbein, Heiner

2011-03-01

The aim of the study was an analysis of effects and side-effects during mesialization of second molars after extraction of the first permanent molars using the anterior dentition/premolars (PM) as an anchorage unit. A total of 35 patients were examined retrospectively who had undergone unilateral or bilateral first permanent molar extraction in the upper or lower arch due to carious lesions. Space closure was carried out in all cases through mesialization of the second molar using an elastic chain fixed to an edgewise stainless steel archwire and tying the anterior dentition/PM together with a continuous laceback ligature. Tooth movement was assessed from lateral cephalograms, orthopantomograms (OPGs) and images of the patient's study casts taken before and after the end of therapy. Space closure after first molar extractions by mesialization of the second molars without skeletal anchorage was largely achieved by bodily forward movement of the teeth, including a small tipping component or tooth-uprighting component when molars were already mesially inclined. Unilateral and bilateral mesialization of the second molars led to retrusion in the maxilla and mandible [(∆incl.=-3.6° (max., bil.), ∆incl.=-4.2° (mand., bil.)] and to translational retraction [(∆s=-2.3 mm (max., bil.), ∆s=-1.6 mm (mand., bil.)] of the incisors. Examination of the soft tissues revealed an increased posterior displacement of the upper and lower lips to the esthetic line [(∆s=-2.8 mm (max. bil.), ∆s=-2.2 mm (mand., bil.)]. In cases of unilateral mesialization less than 50% of the patients had a slight midline deviation in the mandible towards the extraction side. Side effects during mesialization of the second molars without skeletal anchorage in the anterior dentition/PM were observed primarily affecting the incisors integrated into the anterior anchorage unit. These side-effects resulted in posterior displacement of the soft tissues, including a change in profile. This must be

Distinct Signaling Pathways After Higher or Lower Doses of Radiation in Three Closely Related Human Lymphoblast Cell Lines

International Nuclear Information System (INIS)

Lu, T.-P.; Lai, L.-C.; Lin, B.-I.; Chen, L.-H.; Hsiao, T.-H.; Liber, Howard L.; Cook, John A.; Mitchell, James B.; Tsai, M.-H.; Chuang, Eric Y.

2010-01-01

Purpose: The tumor suppressor p53 plays an essential role in cellular responses to DNA damage caused by ionizing radiation; therefore, this study aims to further explore the role that p53 plays at different doses of radiation. Materials and Methods: The global cellular responses to higher-dose (10 Gy) and lower dose (iso-survival dose, i.e., the respective D0 levels) radiation were analyzed using microarrays in three human lymphoblast cell lines with different p53 status: TK6 (wild-type p53), NH32 (p53-null), and WTK1 (mutant p53). Total RNAs were extracted from cells harvested at 0, 1, 3, 6, 9, and 24 h after higher and lower dose radiation exposures. Template-based clustering, hierarchical clustering, and principle component analysis were applied to examine the transcriptional profiles. Results: Differential expression profiles between 10 Gy and iso-survival radiation in cells with different p53 status were observed. Moreover, distinct gene expression patterns were exhibited among these three cells after 10 Gy radiation treatment, but similar transcriptional responses were observed in TK6 and NH32 cells treated with iso-survival radiation. Conclusions: After 10 Gy radiation exposure, the p53 signaling pathway played an important role in TK6, whereas the NFkB signaling pathway appeared to replace the role of p53 in WTK1. In contrast, after iso-survival radiation treatment, E2F4 seemed to play a dominant role independent of p53 status. This study dissected the impacts of p53, NFkB and E2F4 in response to higher or lower doses of γ-irradiation.

Molar exergy and flow exergy of pure chemical fuels

International Nuclear Information System (INIS)

Zanchini, Enzo; Terlizzese, Tiziano

2009-01-01

Expressions of the molar exergy and of the molar flow exergy of a pure chemical fuel are deduced rigorously from the basic principles of thermodynamics. It is shown that molar exergy and molar flow exergy coincide when the temperature T and the pressure p of the fuel are equal to the temperature T B and the pressure p B of the environment; a general relation between exergy and flow exergy is proved as a consequence. The deduction of the expression of the molar exergy of a chemical fuel for non-standard values of T B and p B is clarified. For hydrogen, carbon dioxide and several hydrocarbons, tables are reported to allow a simple calculation of the molar exergy of the fuel for any value of the temperature T B and the relative humidity φ B of the environment, in the range 268.15 K ≤ T B ≤ 313.15 K and 0.1 ≤ φ B ≤ 1, with reference to the standard atmospheric pressure. Additional tables are provided to evaluate the difference between the exergy or the flow exergy of the fuel in its given initial state and the exergy at T = T B and p = p B . In these tables, it is assumed that fuel and environment have the same temperature and that the fuel pressure varies in the range 1.01325 bar ≤ p ≤ 200 bar; the fuel may be gas or liquid.

Microleakage of different adhesive systems in primary molars ...

African Journals Online (AJOL)

Background and aim: This study aimed to examine the microleakage of class V cavities of primary molars prepared by either a conventional dental bur or Er:YAG laser and one of two different adhesive systems. Methods: A total of 50 tooth samples from primary molars were used in this study. They were randomly assigned ...

Effect on mechanical properties of glass reinforced epoxy (GRE) pipe filled with different geopolymer filler molarity for piping application

Science.gov (United States)

Hashim, M. F. Abu; Abdullah, M. M. A.; Ghazali, C. M. R.; Hussin, K.; Binhussain, M.

2017-04-01

This study investigated the use of a novel white clay geopolymer as a filler to produce high strength glass reinforced epoxy pipe. It was found that using white clay geopolymer as filler gives better compressive strength to the glass reinforced epoxy pipe. The disadvantages of current glass reinforced epoxy pipes such low compressive strength which can be replaced by the composite pipes. Geopolymerization is an innovative technology that can transform several aluminosilicate materials into useful products called geopolymers or inorganic polymers. A series of glass reinforced epoxy pipe and glass reinforced epoxy pipe filled with 10 - 40 weight percentages white clay geopolymer filler with 4 Molarity and 8 Molarity were prepared. Morphology of white clay geopolymer filler surface was indicates using scanning electron microscopy. The additions of white clay geopolymer filler for both 4 Molarity and 8 Molarity show higher compressive strength than glass reinforced epoxy pipe without any geopolymer filler. The compressive test of these epoxy geopolymer pipe samples was determined using Instron Universal Testing under compression mode. Nonetheless, the compressive strength of glass reinforced epoxy pipe with white clay geopolymer filler continues to drop when added to 40 wt% of the geopolymer filler loading for both 4 Molarity and 8 Molarity. These outcomes showed that the mixing of geopolymer materials in epoxy system can be attained in this research.

Patients’ satisfaction and prevalence of complications on surgical extraction of third molar

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Lee CTY

2015-02-01

Full Text Available Crystal TY Lee, Shinan Zhang, Yiu Yan Leung, Samantha KY Li, Cissy C Tsang, Chun-Hung Chu Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, People’s Republic of China Objectives: To study patients’ satisfaction and prevalence of complications in surgical extraction of impacted third molar by senior dentists and recently graduated dentists in a university dental clinic. Method: Patients who had impacted third molar extraction in a university dental clinic by two associate dentists who had <2 years of experience and two senior dentists who had >15 years of experience were evaluated in this study. Patients’ age, sex, history of pericoronitis, tooth extracted, and radiographic assessment of the impacted tooth were recorded. Immediately after suture removal, the patients were invited to indicate their satisfaction on a Likert scale of 1–5. Results: A total of 546 patients received extraction, and 251 patients were operated by associate dentists. Patient satisfaction was higher among those who had noncomplicated surgery (P=0.007, short treatment time (P<0.001, and had no postsurgical emergency appointments (P<0.001. The prevalence of seeking postsurgical emergency appointments was 9.2%. The reasons were severe pain (4.8%, swelling (2.6%, bleeding (2.4%, alveolar osteitis (0.9%, paresthesia (0.9, and trismus (0.5%. The prevalence of postsurgical complication(s in associate dentists and senior dentists was 11.6% and 7.1%, respectively (P=0.050. The mean satisfaction scores for associate dentists and senior dentists were 4.17 and 3.95, respectively (P=0.002. Conclusion: Although a higher rate of postsurgical complications was observed among the patients treated by the recently graduated dentists, their patients’ satisfaction scores were higher than that of the senior dentists. Around 9% of patients attended postsurgical emergency appointments, and their common reason was severe pain. Keywords: dental satisfaction, dentistry

Standard molar enthalpies of formation of monochloroacetophenone isomers

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Amaral, Luisa M.P.F.

2010-01-01

The standard (p 0 =0.1MPa) molar enthalpies of formation of the liquids 2'-, 3'-, and 4'-chloroacetophenones were derived from the standard molar energies of combustion, in oxygen, to yield CO 2 (g) and HCl . 600H 2 O(l), at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The Calvet microcalorimetry was used to measure the enthalpies of vaporization of the three compounds. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the chloroacetophenone isomers, in the gaseous phase, at T = 298.15 K. (table) An empirical scheme, developed by Cox, was used to estimate the gas-phase enthalpies of formation and the obtained values were compared with the experimental ones.

Higher dose rate Gamma Knife radiosurgery may provide earlier and longer-lasting pain relief for patients with trigeminal neuralgia.

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Lee, John Y K; Sandhu, Sukhmeet; Miller, Denise; Solberg, Timothy; Dorsey, Jay F; Alonso-Basanta, Michelle

2015-10-01

Gamma Knife radiosurgery (GKRS) utilizes cobalt-60 as its radiation source, and thus dose rate varies as the fixed source decays over its half-life of approximately 5.26 years. This natural decay results in increasing treatment times when delivering the same cumulative dose. It is also possible, however, that the biological effective dose may change based on this dose rate even if the total dose is kept constant. Because patients are generally treated in a uniform manner, radiosurgery for trigeminal neuralgia (TN) represents a clinical model whereby biological efficacy can be tested. The authors hypothesized that higher dose rates would result in earlier and more complete pain relief but only if measured with a sensitive pain assessment tool. One hundred thirty-three patients were treated with the Gamma Knife Model 4C unit at a single center by a single neurosurgeon during a single cobalt life cycle from January 2006 to May 2012. All patients were treated with 80 Gy with a single 4-mm isocenter without blocking. Using an output factor of 0.87, dose rates ranged from 1.28 to 2.95 Gy/min. The Brief Pain Inventory (BPI)-Facial was administered before the procedure and at the first follow-up office visit 1 month from the procedure (mean 1.3 months). Phone calls were made to evaluate patients after their procedures as part of a retrospective study. Univariate and multivariate linear regression was performed on several independent variables, including sex, age in deciles, diagnosis, follow-up duration, prior surgery, and dose rate. In the short-term analysis (mean 1.3 months), patients' self-reported pain intensity at its worst was significantly correlated with dose rate on multivariate analysis (p = 0.028). Similarly, patients' self-reported interference with activities of daily living was closely correlated with dose rate on multivariate analysis (p = 0.067). A 1 Gy/min decrease in dose rate resulted in a 17% decrease in pain intensity at its worst and a 22% decrease

Prevalence and morphometric analysis of three-rooted mandibular first molars in a Brazilian subpopulation

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Clarissa Teles Rodrigues

Full Text Available ABSTRACT The knowledge of the internal anatomy of three-rooted mandibular molars may help clinicians to diagnose and plan the root canal treatment in order to provide adequate therapy when this variation is present. Objectives: To determine the prevalence of three-rooted mandibular molars in a Brazilian population using cone beam computed tomography (CBCT and to analyze the anatomy of mandibular first molars with three roots through micro-CT. Material and Methods: CBCT images of 116 patients were reviewed to determine the prevalence of three-rooted first mandibular molars in a Brazilian subpopulation. Furthermore, with the use of micro-CT, 55 extracted three-rooted mandibular first molars were scanned and reconstructed to assess root length, distance between canal orifices, apical diameter, Vertucci's classification, presence of apical delta, number of foramina and furcations, lateral and accessory canals. The distance between the orifice on the pulp chamber floor and the beginning of the curvature and the angle of canal curvature were analyzed in the distolingual root. Data were compared using the Kruskal-Wallis test (α=0.05. Results: The prevalence of three-rooted mandibular first molars was of 2.58%. Mesial roots showed complex distribution of the root canal system in comparison to the distal roots. The median of major diameters of mesiobuccal, mesiolingual and single mesial canals were: 0.34, 0.41 and 0.60 mm, respectively. The higher values of major diameters were found in the distobuccal canals (0.56 mm and the lower diameters in the distolingual canals (0.29 mm. The lowest orifice distance was found between the mesial canals (MB-ML and the highest distance between the distal root canals (DB-DL. Almost all distal roots had one root canal and one apical foramen with few accessory canals. Conclusions: Distolingual root generally has short length, severe curvature and a single root canal with low apical diameter.

Comparative Efficacy of Amoxicillin/Clavulanic Acid and Levofloxacin in the Reduction of Postsurgical Sequelae After Third Molar Surgery: A Randomized, Double-Blind, Clinical Trial in a Nigerian University Teaching Hospital.

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Ndukwe, Kizito Chioma; Braimah, Ramat Oyebunmi; Owotade, John Foluso; Aregbesola, Stephen Babatunde

2016-01-01

The most common sequelae after surgical removal of mandibular third molar are pain, trismus, swelling, and dysphagia. However, these symptoms can also signal the onset of surgical site infection and alveoli osteitis. The aim of this study was to evaluate the efficacy of prophylactic amoxicillin/clavulanic acid and levofloxacin and preemptive therapy of amoxicillin/clavulanic acid in the reduction of postinflammatory complications, surgical site infection, and alveolar osteitis following the third molar surgery. A total of 135 patients were randomized into three equal groups: Group A (preemptive therapy of amoxicillin/clavulanic acid) with preoperative dose of 875/125 mg amoxicillin/clavulanic acid followed by 500/125 mg amoxicillin/clavulanic acid 12 hourly for 5 days, Group B (amoxicillin/clavulanic acid prophylaxis) with a single preoperative dose of amoxicillin/clavulanic acid 875/125 mg tablets, and Group C (levofloxacin prophylaxis) with a single preoperative dose of levofloxacin 1000 mg tablets. All patients had ostectomy using surgical handpiece and burs and received same analgesics (tabs ibuprofen 400 mg 8 hourly for 3 days). No case of surgical site infection or alveoli osteitis was recorded in the study groups. There were no statistically significant differences between the treatment groups with regard to pain, mouth opening, postoperative facial dimension, and body temperature. Amoxicillin/clavulanic acid as a single preoperative bolus should be adequate for the prevention of postoperative wound infection and alveoli osteitis following the third molar extraction as there is no need for an extension of the antibiotic. Moreover, levofloxacin can be utilized as prophylaxis in patients undergoing mandibular third molar extraction if such patients are allergic to penicillins.

Comparative efficacy of amoxicillin/clavulanic acid and levofloxacin in the reduction of postsurgical sequelae after third molar surgery: a randomized, double-blind, clinical trial in a Nigerian university teaching hospital

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Kizito Chioma Ndukwe

2016-01-01

Full Text Available Background: The most common sequelae after surgical removal of mandibular third molar are pain, trismus, swelling, and dysphagia. However, these symptoms can also signal the onset of surgical site infection and alveoli osteitis. The aim of this study was to evaluate the efficacy of prophylactic amoxicillin/clavulanic acid and levofloxacin and preemptive therapy of amoxicillin/clavulanic acid in the reduction of postinflammatory complications, surgical site infection, and alveolar osteitis following the third molar surgery. Patients and Methods: A total of 135 patients were randomized into three equal groups: Group A (preemptive therapy of amoxicillin/clavulanic acid with preoperative dose of 875/125 mg amoxicillin/clavulanic acid followed by 500/125 mg amoxicillin/clavulanic acid 12 hourly for 5 days, Group B (amoxicillin/clavulanic acid prophylaxis with a single preoperative dose of amoxicillin/clavulanic acid 875/125 mg tablets, and Group C (levofloxacin prophylaxis with a single preoperative dose of levofloxacin 1000 mg tablets. All patients had ostectomy using surgical handpiece and burs and received same analgesics (tabs ibuprofen 400 mg 8 hourly for 3 days. Results: No case of surgical site infection or alveoli osteitis was recorded in the study groups. There were no statistically significant differences between the treatment groups with regard to pain, mouth opening, postoperative facial dimension, and body temperature. Conclusion: Amoxicillin/clavulanic acid as a single preoperative bolus should be adequate for the prevention of postoperative wound infection and alveoli osteitis following the third molar extraction as there is no need for an extension of the antibiotic. Moreover, levofloxacin can be utilized as prophylaxis in patients undergoing mandibular third molar extraction if such patients are allergic to penicillins.

Incisor and molar overjet, arch contraction, and molar relationship in the mixed dentition in repaired complete unilateral cleft lip and palate: A qualitative and quantitative appraisal.

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Disthaporn, Suteeta; Suri, Sunjay; Ross, Bruce; Tompson, Bryan; Baena, Diogenes; Fisher, David; Lou, Wendy

2017-07-01

To compare the mixed dentition incisor and molar overjet, severity of contraction of the dental arch, and the sagittal molar relationship on the cleft side vs the noncleft side in children with repaired complete unilateral cleft of the lip and palate (UCLP). Orthodontic records taken prior to orthodontic preparation for alveolar bone grafting were screened to select study casts from patients with nonsyndromic repaired complete UCLP who did not have mandibular skeletal or dental asymmetry. The study sample comprised dental casts from 74 children aged 8.9 ± 1 years. Standardized digital photographs were acquired at 1:1 magnification. A coordinate system was developed using digital image-processing software (Photoshop CS4 and Adobe Illustrator). Incisor and molar overjet, Angle's classification, and arch contraction were recorded. Descriptive statistics, paired t-tests, and kappa statistics were used to compare the cleft and noncleft sides. A negative overjet of -1 to -5 mm was often present at the incisors, with greater frequency and magnitude on the cleft side. Class II molar relation was more frequent on the cleft side (61.1%) than on the noncleft side (47.2%). Significantly greater contraction of the cleft side deciduous canine and deciduous first molar was noted, while the difference was very minor at the first permanent molar. Cleft side maxillary arch contraction was most severe in the deciduous canine and first deciduous molar region and progressively less severe in the posterior region of the arch. A greater frequency and severity of negative overjet and Class II molar relationship was seen on the cleft side.

Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars.

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Kurthukoti, Ameet J; Sharma, Pranjal; Swamy, Dinesh Francis; Shashidara, R; Swamy, Elaine Barretto

2015-01-01

Need for the study: The most important procedure for a successful endodontic treatment is the cleaning and shaping of the canal system. Understanding the internal anatomy of teeth provides valuable information to the clinician that would help him achieve higher clinical success during endodontic therapy. To evaluate by computed tomography-the internal anatomy of mandibular second primary molars with respect to the number of canals, cross-sectional shape of canals, cross-sectional area of canals and the root dentin thickness. A total of 31 mandibular second primary molars were subjected to computed-tomographic evaluation in the transverse plane, after mounting them in a prefabricated template. The images, thus, obtained were analyzed using De-winter Bio-wizard® software. All the samples demonstrated two canals in the mesial root, while majority of the samples (65.48%) demonstrated two canals in the distal root. The cross-sectional images of the mesial canals demonstrated a round shape, while the distal canals demonstrated an irregular shape. The root dentin thickness was highly reduced on the distal aspect of mesial and mesial aspect of distal canals. The mandibular second primary molars demonstrated wide variation and complexities in their internal anatomy. A thorough understanding of the complexity of the root canal system is essential for understanding the principles and problems of shaping and cleaning, determining the apical limits and dimensions of canal preparations, and for performing successful endodontic procedures. How to cite this article: Kurthukoti AJ, Sharma P, Swamy DF, Shashidara R, Swamy EB. Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars. Int J Clin Pediatr Dent 2015;8(3):202-207.

Effect of age, impaction types and operative time on inflammatory tissue reactions following lower third molar surgery

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Obi Emeka V

2011-04-01

Full Text Available Abstract Background Postoperative mobidity following third molar surgery is affected by a number of factors. The study of these factors is essential for effective planning and limitation of morbidity. The aim of this study was to determine the effect of age, type of impaction and operative time on immediate postoperative tissue reactions following mandibular third molar surgery. Methods Consecutive patients with impacted mandibular third molar teeth were studied. All the third molars were classified according to Winter's classification. Surgical extraction was performed on all the patients by a single surgeon under local anaesthesia. The operation time was determined by the time lapse between incision and completion of suturing. Postoperative pain, swelling and trismus were evaluated. Results There were 120 patients with an age range of 19-42 years. Patients in the age range of 35-42 years recorded a lower pain score (p = 0.5 on day 1. The mouth opening was much better in the lower age group on day 2 and 5 (p = 0.007 and p = 0.01 respectively. Pain, swelling and trismus increased with increasing operative time. Distoangular impaction was significantly associated with higher VAS score on day 1 and 2 (p = 0.01, 0.0, 04. Distoangular and horizontal impaction are associated with a higher degree of swelling and reduced mouth opening on postoperative review days. Vertical impaction was associated with the least degree of facial swelling and best mouth opening. Conclusions Increasing operating time and advancing age are associated with more postoperative morbidity, likewise distoangular and horizontal impaction types.

First molar cross-bite is more closely associated with a reverse chewing cycle than anterior or pre-molar cross-bite during mastication.

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Tomonari, H; Ikemori, T; Kubota, T; Uehara, S; Miyawaki, S

2014-12-01

A posterior cross-bite is defined as an abnormal bucco-lingual relationship between opposing molars, pre-molars or both in centric occlusion. Although it has been reported that patients with unilateral posterior cross-bite often show unique chewing patterns, the relationship between the form of cross-bite and masticatory jaw movement remains unclear in adult patients. The objective of this study was to investigate masticatory jaw movement among different forms of cross-bite. One hundred and one adults were recruited in this study: 27 had unilateral first molar cross-bite (MC group); 28, unilateral pre-molar cross-bite (PC group); 23, anterior cross-bite (AC group); and 23, normal occlusion (control group). Masticatory jaw movement of the lower incisor point was recorded with six degrees of freedom jaw-tracking system during unilateral mastication. Our results showed that the reverse chewing ratio during deliberate unilateral mastication was significantly larger in the MC group than in the PA (P chewing cycle. © 2014 John Wiley & Sons Ltd.

The molar hydrodynamic volume changes of factor VIIa due to GlycoPEGylation

DEFF Research Database (Denmark)

Plesner, Bitten; Westh, Peter; Hvidt, Søren

2011-01-01

The effects of GlycoPEGylation on the molar hydrodynamic volume of recombinant human rFVIIa were investigated using rFVIIa and two GlycoPEGylated recombinant human FVIIa derivatives, a linear 10 kDa PEG and a branched 40 kDa PEG, respectively. Molar hydrodynamic volumes were determined by capillary......, that the molar hydrodynamic volume of the conjugated protein is not just an addition of the molar hydrodynamic volume of the PEG and the protein. The molar hydrodynamic volume of the GlycoPEGylated protein is larger than the volume of its composites. These results suggest that both the linear and the branched...

Observation of positional relation between mandibular third molars and the mandibular canal on limited cone beam computed tomography

International Nuclear Information System (INIS)

Hashizume, Atsuko; Nakagawa, Yoichi; Ishii, Hisako; Kobayashi, Kaoru

2004-01-01

We describe the preoperative use of limited cone beam computed tomography (CT) with a dental CT scanner for the assessment of mandibular third molars before extraction. Cone beam CT provides 42.7-mm-high and 30-mm-wide rectangular solid images, with a resolution of less than 0.2 mm. The positional relationship between the mandibular third molars and the mandibular canal was examined by dental CT. Sixty-eight lower third molars of 62 patients whose teeth were superimposed on the mandibular canal on periapical or panoramic radiographs were studied. Dental CT scans clearly demonstrated the positional relationship between the mandibular canal and the teeth. The mandibular canal was located buccally to the roots of 16 teeth, lingually to the roots of 27 teeth, inferiorly to the roots of 23 teeth, and between the roots of 2 teeth. The presence of bone between the mandibular canal and the teeth was not noted in 7 of 16 buccal cases, 24 of 27 lingual cases, and 10 of 23 inferior cases on dental CT scans, suggesting that the canal was in contact with the teeth. Fifty-nine of the 68 mandibular third molars were surgically removed, and postoperative transient hypoesthesia occurred in 4 patients. Dental CT scans showed no bone between the mandibular canal and the teeth in all 4 patients. Hypoesthesia was not related to the bucco-lingual location of the mandibular canal or to the extent of bone loss between the canal and the teeth. However, hypoesthesia did not occur in patients with bone between the mandibular canal and the teeth. Thus, information on the distance between the canal and teeth on dental CT scans was useful for predicting the risk of inferior alveolar nerve damage. Because of its high resolution and low radiation dose, cone beam CT was useful for examination before mandibular third molar surgery. (author)

Movimentação de molares inferiores ancorados em mini-parafusos Mandibular molar uprighting, using mini-screw as anchorage

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Rosana Canteras Di Matteo

2005-08-01

Full Text Available Freqüentemente a movimentação ortodôntica exige recursos adicionais de ancoragem. Os mini-parafusos têm-se apresentado como uma possível solução. O propósito deste trabalho foi estabelecer um método para a verticalização de molares inferiores inclinados para mesial, utilizando ancoragem em mini-parafusos colocados na região de linha oblíqüa externa da mandíbula. Foram selecionados três pacientes entre 40 a 48 anos (dois do gênero feminino, um do gênero masculino, com molares inferiores inclinados para mesial e distalmente posicionados às áreas edêntulas. Os pacientes foram tratados ortodonticamente durante um período de 6 a 12 meses, com técnica ortodôntica MD3. Mini-parafusos de titânio foram colocados bilateralmente com anestesia local. Uma incisão sobre a linha oblíqüa externa da mandíbula, medindo aproximadamente 1 cm foi realizada em cada lado, distalmente aos molares inclinados. Após descolamento muco-periosteal, mini-parafusos foram implantados e foram realizadas suturas deixando suas cabeças exteriorizadas. Uma semana após a remoção das suturas, cargas ortodônticas (entre 150 a 200 gramas/força foram aplicadas através de forças elásticas. Verificamos que alguma inflamação foi observada ao redor dos mini-parafusos, mas foi controlada com procedimentos de higienização. O procedimento cirúrgico é simples, podendo ser realizado pelo ortodontista; as formas dimensionais dos mini-parafusos são adequadas e estes são de fácil remoção após uso. Concluímos que o uso de mini-parafusos representa uma alternativa efetiva de ancoragem ortodôntica na verticalização de molares inferiores.Tooth movement frequently requires additional anchorage resources. Mini-screws have been used as a possible solution to this matter. The purpose of this study was to establish a method of mandibular molar uprighting, using mini-screw as anchorage, positioned on the mandibular external oblique line, behind and

Relationship between mandibular condyle and angle fractures and the presence of mandibular third molars.

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Mah, Deuk-Hyun; Kim, Su-Gwan; Moon, Seong-Yong; Oh, Ji-Su; You, Jae-Seek

2015-02-01

We retrospectively evaluated the impact of mandibular third molars on the occurrence of angle and condyle fractures. This was a retrospective investigation using patient records and radiographs. The sample set consisted of 440 patients with mandibular fractures. Eruption space, depth and angulation of the third molar were measured. Of the 144 angle fracture patients, 130 patients had third molars and 14 patients did not. The ratio of angle fractures when a third molar was present (1.26 : 1) was greater than when no third molar was present (0.19 : 1; odds ratio, 6.58; Pcondyle fractures patients, the third molar was present in 84 patients and absent in 57 patients. The ratio of condyle fractures when a third molar was present (0.56 : 1) was lower than when no third molar was present (1.90 : 1; odds ratio, 0.30; Pfractures with third molars and the ratio of condyle fractures without a third molar were statistically significant. The occurrence of angle and condyle fractures was more affected by the continuity of the cortical bone at the angle than by the depth of a third molar. These results demonstrate that a third molar can be a determining factor in angle and condyle fractures.

Microstructure of a tribosphenic molar - comparative analysis

OpenAIRE

ŠPOUTIL, František

2010-01-01

The proposed thesis concerns in the study of tribosphenic molar, the key apomorphy of mammalian clade, mainly in structure and development of its enamel coat. As the main model species served us European vespertilionid bat Myotis myotis. The aims of this thesis are: (1) to describe structure and microstructure of enamel in tribosphenic molars in detail; (2) to compare it with unicuspid teeth of the same dentition; (3) to describe mineralization process and enamel maturation in insectivorous d...

Distribution and characteristics of molar-incisor hypomineralization

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Janković Svjetlana

2014-01-01

Full Text Available Background/Aim. Developmental disorders of teeth are the problems that are becoming more present in pediatric dentistry, especially on first permanent molars and incisors. Molar Incisor Hypomineralization (MIH is proposed term for this phenomenon. The aim of this study was to establish the MIH prevalence in children living in the Foča municipality (Bosnia and Herzegovina as well as to assess characteristics and expression of hypomineralization within the tested population. Methods. A total of 141 children from the Foča municipality, 8 years of age, were included in this study. Criteria according to Weerhejm have been used for diagnosis of hypomineralization: demarcated opacity (DO, post-eruptive breakdown (PEB, atypical restoration (AR, extracted molars due to MIH (E-MIH and unerupted tooth (UT. Level and the prominence of color changes have been determined for patients with DO, PEB and AR. Results. MIH in this area was present in 12.8% of children. The prevalence of MIH changes expressed in percentages was as follows: DO was at 9.2%, PEB in 3.5%, AR in 5.6%, while E-MIH was 5.6%. A total of 9.9% of the examinees had mild, 5.6% moderate, and 7.8% severe form of MIH. White form of MIH defects was found in 9.9% of the examinees, white-yellow one in 5.6% and yellow-brown color in 3.5% of the examined children. These changes were more often present in the lower jaw (60.3%. In total, 6.4% of children had these changes present only on molars, while 6.4% of them both on molars and incisors simultaneously. Conclusion. A total of 12.8% of the examinees with MIH is not to be disregarded. With timely diagnosis, prevention and therapy complications could be avoided or mitigated.

Fatigue resistance of CAD/CAM resin composite molar crowns.

NARCIS (Netherlands)

Shembish, F.A.; Tong, H.; Kaizer, M.; Janal, M.N.; Thompson, V.P.; Opdam, N.J.M.; Zhang, Y.

2016-01-01

OBJECTIVE: To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. METHODS: Fully anatomically shaped monolithic resin composite molar crowns (Lava

Endodontic treatment of an unusual connation of permanent mandibular molars: a case report.

Science.gov (United States)

Liu, Shengbo; Fan, Bing; Peng, Bin; Fan, Mingwen; Bian, Zhuan

2006-10-01

A 27-year-old patient with an anomalous mandibular molar was referred for endodontic therapy. Clinical and radiographic examination revealed the connation of a second mandibular molar with a third molar. Challenging endodontic therapy was performed in the unusual connated molars. A 2-year recall showed good treatment result.

MicroCT study on the enamel mineral density of primary molars

NARCIS (Netherlands)

Elfrink, M.E.C.; Kalin, K.; van Ruijven, L.J.; ten Cate, J.M.; Veerkamp, J.S.J.

2016-01-01

Aim The aim of this study is to report on the mineral density of the enamel of primary molars related to the age of the child and to compare the mineral density of sound and carious enamel in those molars. Materials and methods This study included 23 children and 41 extracted primary molars. The

Standard molar enthalpies of formation of monochloroacetophenone isomers

Energy Technology Data Exchange (ETDEWEB)

Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.p [Centro de Investigacao em Quimica, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Amaral, Luisa M.P.F. [Centro de Investigacao em Quimica, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

2010-12-15

The standard (p{sup 0}=0.1MPa) molar enthalpies of formation of the liquids 2'-, 3'-, and 4'-chloroacetophenones were derived from the standard molar energies of combustion, in oxygen, to yield CO{sub 2}(g) and HCl . 600H{sub 2}O(l), at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The Calvet microcalorimetry was used to measure the enthalpies of vaporization of the three compounds. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the chloroacetophenone isomers, in the gaseous phase, at T = 298.15 K. (table) An empirical scheme, developed by Cox, was used to estimate the gas-phase enthalpies of formation and the obtained values were compared with the experimental ones.

Three-dimensional analysis of third molar development to estimate age of majority.

Science.gov (United States)

Márquez-Ruiz, Ana Belén; Treviño-Tijerina, María Concepción; González-Herrera, Lucas; Sánchez, Belén; González-Ramírez, Amanda Rocío; Valenzuela, Aurora

2017-09-01

Third molars are one of the few biological markers available for age estimation in undocumented juveniles close the legal age of majority, assuming an age of 18years as the most frequent legal demarcation between child and adult status. To obtain more accurate visualization and evaluation of third molar mineralization patterns from computed tomography images, a new software application, DentaVol©, was developed. Third molar mineralization according to qualitative (Demirjian's maturational stage) and quantitative parameters (third molar volume) of dental development was assessed in multi-slice helical computed tomography images of both maxillary arches displayed by DentaVol© from 135 individuals (62 females and 73 males) aged between 14 and 23years. Intra- and inter-observer agreement values were remarkably high for both evaluation procedures and for all third molars. A linear correlation between third molar mineralization and chronological age was found, with third molar maturity occurring earlier in males than in females. Assessment of dental development with both procedures, by using DentaVol© software, can be considered a good indicator of age of majority (18years or older) in all third molars. Our results indicated that virtual computed tomography imaging can be considered a valid alternative to orthopantomography for evaluations of third molar mineralization, and therefore a complementary tool for determining the age of majority. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

Size of the lower third molar space in relation to age in Serbian population.

Science.gov (United States)

Zelić, Ksenija; Nedeljković, Nenad

2013-10-01

It is considered that the shortage of space is the major cause of the third molar impaction. The aim of this study was to establish the frequency of insufficient lower third molar eruption space in Serbian population, to question the differences in this frequency in the subjects of different age, to determine the influence of the lower third molar space (retromolar space) size on third molar eruption, and to investigate a possible correlation between the size of gonial angle and the space/third molar width ratio. Digital orthopantomograms were taken from 93 patients divided into two groups: early adult (16-18 years of age) and adult (18-26) patients. Retromolar space, mesiodistal third molar crown width, gonial angle and eruption levels were measured. The space/third molar width in early adult subjects was smaller (p third molars erupted in case of enough space in both age groups (p third molar width ratio is more favorable in adult subjects. Gonial angle is not in correlation with the retromolar space/third molar width ratio.

Management of large losses of substances molars

OpenAIRE

Reynal, Florence

2016-01-01

This work aims to compare the different coronary restorative materials used for large tooth losses in primary molars. The first part of this thesis is dedicated to a description of the four main materials used in coronary restorations of molars : amalgam, glass-ionomer cements, resin-based composite and pedodontic crown. The second part is a systematic review of the literature. The aim is to compare the long-term survival rates of different restoration techniques, in order to help the practit...

Anomalous viscosity behavior of a bicelle system with various molar ratios of short-and long-chain phospholipids

International Nuclear Information System (INIS)

Hwang, Jimmy S.; Oweimreen, Ghassan A.

2003-01-01

Viscosity versus temperature curves were obtained for five DMPC/DHPC/H2O bilayer systems with DMPC/DHPC molar ratios of 3.2, 2.8, 2.5, 2.0 and 1.5. The curves showed the viscosity maxima that shifted to higher temperatures as the mole fraction of DHPC increased. The maxima are extremely high for the first three systems and are estimated to be no less than 600 Pa,s. The shift to higher temperature is explained in terms of decrease in the the coalescence of the bicells as the mole fraction of DHPC increases. The maxima are attributed to two competing effects; the normal decrease in viscosity with temperature is counterbalanced at low to moderate temperatures with an increase in viscosity resulting from coalescence. Such coalescence increases as the DMPC /DHPC molar ratio increases. (author)

Relationship between fracture of mandibular condyle and absence of unerupted mandibular third molar-a retrospective study.

Science.gov (United States)

Rajan, Ritesh; Verma, Dinesh Kumar; Borle, R M; Yadav, Abhilasha

2016-06-01

The purpose of the present study was to find, if there exists, a co-relation between presence of unerupted mandibular third molar and fracture of mandibular condyle. A retrospective, multicenter study was done collecting the data of all mandibular condyle fractures treated from November 2006 till August 2015. Data was collected from the patient's records and radiographs for the following information: age, sex, etiology of fracture, presence and state of lower third molars, and associated fracture. The results were subjected to statistical analysis. Out of 180 patients of condylar fracture, unerupted third molars were present in 35 (19.44 %) cases compared to 145 (80.55 %) cases of condylar fracture where the unerupted third molars were not present. The difference was statistically significant (p fracture was seen in 4 (11.4 %) cases, bilateral condylar fracture associated with other mandibular fractures in 9 (25.7 %) cases, isolated unilateral condylar fracture in 0 (0.0 %) cases, and unilateral condylar fracture associated with other mandibular fractures in 17 (48.5 %) cases and condylar fracture associated with mid face fractures in 5 (14.2 %) cases. In the unerupted third molar absent group, isolated bilateral condylar fracture was seen in 5 (3.4 %) cases, bilateral condylar fracture associated with other mandibular fractures in 30 (20.6 %) cases, isolated unilateral condylar fracture in 24 (16.5 %) cases, unilateral condylar fracture associated with other mandibular fractures in 73 (50.34 %) cases, and condylar fracture associated with mid face fractures in 13(8.96 %) cases. The difference between the groups was statistically significant (p = 0.032). This study suggests that the fractures of mandibular condylar region have a significantly higher incidence in patients without an unerupted mandibular third molar.

Molaren Inzisiven Hypomineralisation und Milchmolaren Hypomineralisation - klinisches Erscheinungsbild, Prävalenz und deren Ursachen - Molar Incisor Hypomineralisation and Deciduous Molar Hypomineralisation - clinical appearance, prevalence and determinants for its occurrence

NARCIS (Netherlands)

Elfrink, M.E.C.; Weerheijm, K.L.

2012-01-01

Background: Molar Incisor Hypomineralisation (MIH) and Deciduous Molar Hypomineralisation (DMH) are frequently occurring dental problems in children. Children with MIH have demarcated opacities in their erupting first permanent molars often in combination with demarcated opacities in their permanent

Management of inflammatory complications in third molar surgery: A ...

African Journals Online (AJOL)

Background: Pain, swelling and trismus are common complications associated with third molar surgery. These complications have been reported to have an adverse effect on the quality of life of patients undergoing third molar surgery. Objective: To review the different modalities of minimizing inflammatory complications in ...

The Effect of Sodium Hydroxide Molarity on Strength Development of Non-Cement Class C Fly Ash Geopolymer Mortar

Science.gov (United States)

Wardhono, A.

2018-01-01

The use of fly ash as cement replacement material can overcome the environmental issues, especially the global warming problem caused by the greenhouse effect. This is attributed to the CO2 gas produced during the cement manufacturing process, which 1 ton of cement is equivalent to 1 ton CO2. However, the major problem of fly ash is the requirement of activators to activate the polymer reactions. The most common activator used in non-cement or geopolymer material is the combination of sodium hydroxide (NaOH) and sodium silicate. This study aims to identify the effect of NaOH molarity as activator on strength development of non-cement class C fly ash geopolymer mortar. The molarity variations of NaOH were 6 Molar (M), 8M, 10M, 12M, 14M and 15M. The compressive strength test was performed at the age of 3, 7 and 28 days in accordance with ASTM standard, and the specimens were cured at room temperature. The results show that the highest compressive strength was achieved by geopolymer mortar with a molarity of 12M. It exhibits a higher strength to that normal mortar at 28 days. However, the use of NaOH molarity more than 12M tends to decrease the strength of non-cement geopolymer mortar specimens.

A Comparison of Different Volumes of Articaine for Inferior Alveolar Nerve Block for Molar Teeth with Symptomatic Irreversible Pulpitis.

Science.gov (United States)

Abazarpoor, Ramin; Parirokh, Masoud; Nakhaee, Nouzar; Abbott, Paul V

2015-09-01

Achieving anesthesia in mandibular molar teeth with irreversible pulpitis is very difficult. The aim of this study was to compare the efficacy of 1.8 mL and 3.6 mL articaine for an inferior alveolar nerve block (IANB) when treating molars with symptomatic irreversible pulpitis. In a randomized, double-blind clinical trial, 82 first mandibular molar teeth with symptomatic irreversible pulpitis randomly received conventional IANB injection either with 1 (1.8 mL) or 2 cartridges (3.6 mL) of 4% articaine with 1:100,000 epinephrine. The patients recorded their pain before and during access cavity preparation as well as during root canal instrumentation using a Heft-Parker visual analog scale. No or mild pain was considered as successful anesthesia. Data were analyzed by t and chi-square tests. Eighty patients were eligible to participate in this study, which showed that 3.6 mL articaine provided a significantly higher success rate (77.5%) of IANBs compared with 1.8 mL of the same anesthetic solution (27.5%) although neither group had 100% successful anesthesia (P < .001). Increasing the volume of articaine provided a significantly higher success rate of IANBs in mandibular first molar teeth with symptomatic irreversible pulpitis, but it did not result in 100% anesthetic success. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Measurement of the molar heat capacities of MoO2 and MoO3 from 350 to 950 K

International Nuclear Information System (INIS)

Inaba, H.; Miyahara, K.; Naito, K.

1984-01-01

Molar heat capacities of MoO 2 and MoO 3 were measured in the range between 350 and 950 K by means of adiabatic scanning calorimetry. For MoO 2 , a sharp heat-capacity anomaly with a molar enthalpy change of (178 +- 24) J.mol -1 and a molar entropy change of (0.207 +- 0.028) J.K -1 .mol -1 was observed at 865 K, which had not been detected by drop calorimetry. For MoO 3 , two heat-capacity anomalies with molar enthalpy changes of (88 +- 21) and (60 +- 36) J.mol -1 were found at 808 K and 857 K, respectively; neither anomaly had been detected by the drop method. The lattice molar heat capacities of MoO 2 and MoO 3 are estimated as Csub(l,m)(MoO 2 ) = D(469 K/T) + E(578 K/T) + E(876 K/T) and Csub(l,m)(MoO 3 ) = D(208 K/T) + 2E(488 K/T) + E(1170 K/T), where D(x) and E(x) are the Debye and Einstein functions, respectively. The temperature coefficient of the electronic molar heat capacity of MoO 2 is estimated as (6.0 +- 0.5) mJ.K -2 .mol -1 . The excess heat capacity in MoO 3 found at higher temperatures is interpreted as being due to vacancy formation with a molar activation energy of (98 +-5) kJ.mol -1 . The origin of the heat-capacity anomalies is inferred as arising from the slight movement of distorted MoO 6 octahedra in the MoO 2 and MoO 3 structures. (author)

Radiographic correlation of dental and skeletal age: Third molar, an age indicator.

Science.gov (United States)

Suma, Gn; Rao, Balaji B; Annigeri, Rajeshwari G; Rao, Dayashankara Jk; Goel, Sumit

2011-01-01

Age estimation plays a great role in forensic investigations, orthodontic and surgical treatment planning, and tooth transplantation. Teeth offer an excellent material for age determination by stages of development below the age of 25 years and by secondary changes after the age of 25 years. Third molar is often not included for this purpose due to its notorious developmental patterns. The aim of this study was to evaluate the development of third molar anlage in relation to skeletal maturities and the chronological age. One hundred and fifty-six young individuals, 78 males and 78 females, were selected. The stages of development of all the third molars in every individual were determined from panoramic radiographs. The skeletal development was assessed using hand wrist radiographs. Data were analyzed statistically for mean value, standard deviation and the relationship between the recorded characteristics. A STRONG CORRELATION WAS FOUND BETWEEN THIRD MOLAR DEVELOPMENT AND SKELETAL MATURITY (IN MALES: r=0.88, Pthird molar and 0.89 for mandibular third molar, Page, developmental stages of third molars and maturation of epiphyses of hand. Any of the three parameters could be used for the assessment of other maturities.

Apparent molar volumes and compressibilities of electrolytes and ions in γ-butyrolactone

International Nuclear Information System (INIS)

Krakowiak, Joanna; Wawer, Jarosław; Farmas, Aleksander

2012-01-01

Highlights: ► Density and speed of sound for salts solutions in γ-butyrolactone were measured. ► The apparent molar volumes and compressibilities have been determined. ► The limiting molar quantities are split into independent ionic contributions. ► These data are used to describe ion–solvent interactions. - Abstract: The densities of tetraphenylphosphonium bromide, sodium tetraphenylborate, lithium perchlorate, sodium perchlorate and lithium bromide in γ-butyrolactone at (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K and speed of sound at 298.15 K have been measured. From these data apparent molar volumes V Φ at (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K and the apparent molar isentropic compressibility K S,Φ , at T = 298.15 K of the salts have been determined. The apparent molar volumes and the apparent molar isentropic compressibilities were fitted to the Redlich, Rosenfeld and Mayer equation as well as to the Pitzer and Masson equations yielding infinite dilution data. The obtained limiting values have been used to estimate the ionic data of the standard partial molar volume and the standard partial isentropic compressibility in γ-butyrolactone solutions.

Autotransplantation of a mandibular third molar: A case report

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Elham Najafi

2017-09-01

Full Text Available Tooth autotransplantation defines as transition of one tooth from one position to another, in same individual. It is a biological procedure in which teeth have the potential to induce alveolar bone growth. It can be applied in patients before adolescence growth is finished. It significantly reduces time and cost compared to implants. Healing rapidly occurs and function is regained almost immediately. Our case was a 15-year-old male that his left mandibular third molar transplanted to the second molar sight after extraction of second molar because of unrestorable crown. During 9 month follow up transplanted tooth was asymptomatic, functional and responsive to sensibility tests. (Cold test, EPT.

Variant Root Morphology of Third Mandibular Molar in Normal and ...

African Journals Online (AJOL)

isaac kipyator

2017-11-12

Nov 12, 2017 ... ABSTRACT. The mandibular third molar poses a challenge to dental surgeons due to it's unpredictable morphology ... treatment in the School of Dental Sciences since 2010. ... mandibular third molar include presence of three.

Prevalência de perda precoce de molares decíduos: estudo retrospectivo = Prevalence of early loss of deciduous molars: a retrospective study

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Alessandro Leite Cavalcanti

2008-07-01

Full Text Available Este estudo retrospectivo determinou a prevalência da perda precoce demolares decíduos em pacientes atendidos na clínica de Odontopediatria da Universidade Estadual da Paraíba. Foram examinados 515 prontuários, sendo os dados registrados em um formulário. Foram analisadas as variáveis: gênero, idade, tipo de molar decíduo perdido,arcada dentária (maxilar ou mandibular e lado (direito e esquerdo. Observou-se que a prevalência de perda precoce foi de 15,1%, existindo uma distribuição similar entre os gêneros. Em relação à idade da criança, a maior freqüência de perda acometeu pacientescom sete anos (32,1%. Houve distribuição equitativa da perda dentária entre as arcadas superior e inferior, com 43,6% cada uma, sendo o lado esquerdo o mais acometido (41%. O segundo molar superior esquerdo foi o mais acometido (17,9%, seguido do primeiromolar decíduo superior direito (16,1%. Pode-se concluir que a prevalência de perda precoce foi baixa e que os molares decíduos superiores foram os dentes mais comumente perdidos.This retrospective study determined the prevalence of early loss of deciduous molars in patients enrolled at the Pediatric Dentistry clinic at the State University of Paraíba. A review of 515 patient records were analyzed, registered in a form. The following variables were analyzed: gender, age, type of deciduous molar loss, region (maxilla or mandible and side (right and left. It was observed that the prevalence of early tooth loss was 15.1% and there was a similar distribution between the genders. In regard to age, the greatest frequency of tooth loss involved patients at 7 years old (32.1%. There was a similar distribution of tooth loss between the maxilla and mandible regions, at 43.6% each, with the left side being themost involved (41%. The second upper left deciduous molar was the most commonly missing tooth (17.9%, followed by the first upper right deciduous molar (16.1%. It can be concluded that the

Medium doses of daily vitamin D decrease falls and higher doses of daily vitamin D3 increase falls: A randomized clinical trial.

Science.gov (United States)

Smith, Lynette M; Gallagher, J Christopher; Suiter, Corinna

2017-10-01

Falls are a serious health problem in the aging population. Because low levels of vitamin D have been associated with increased fall rates, many trials have been performed with vitamin D; two meta-analyses showed either a small effect or no effect of vitamin D on falls. We conducted a study of the effect of vitamin D on serum 25 hydroxyvitamin D (25OHD) and data on falls was collected as a secondary outcome. In a 12-month double blind randomized placebo trial, elderly women, mean age 66 years, were randomized to one of seven daily oral doses of vitamin D or placebo. The main inclusion criterion for study was a baseline serum 25OHDvitamin D on falls followed a U-shaped curve whether analyzed by dose or serum 25OHD levels. There was no decrease in falls on low vitamin D doses 400, 800 IU, a significant decrease on medium doses 1600, 2400,3200 IU (p=0.020) and no decrease on high doses 4000, 4800 IU compared to placebo (p=0.55). When compared to 12-month serum 25OHD quintiles, the faller rate was 60% in the lowest quintile <25ng/ml (<50nmol/L), 21% in the low middle quintile 32-38ng/ml (80-95nmo/L), 72% in the high middle quintile 38-46ng/ml (95-115nmo/L) and 45% in the highest quintile 46-66ng/ml (115-165nmol/L). In the subgroup with a fall history, fall rates were 68% on low dose, 27% on medium doses and 100% on higher doses. Fall rates on high doses were increased compared to medium doses (Odds Ratio 5.6.95% CI: 2.1-14.8). In summary, the maximum decrease in falls corresponds to a 12- month serum 25OHD of 32-38ng/ml (80-95nmol/L) and faller rates increase as serum 25OHD exceed 40-45ng/ml (100-112.5nmol/L). The Tolerable upper limit (TUL) recently increased in 2010 from 2000 to 4000 IU/day may need to be reduced in elderly women especially in those with a fall history. Copyright © 2017 Elsevier Ltd. All rights reserved.

Computed Tomographic Morphometry of the Internal Anatomy of Mandibular Second Primary Molars

OpenAIRE

Kurthukoti, Ameet J; Sharma, Pranjal; Swamy, Dinesh Francis; Shashidara, R; Swamy, Elaine Barretto

2015-01-01

ABSTRACT Need for the study: The most important procedure for a successful endodontic treatment is the cleaning and shaping of the canal system. Understanding the internal anatomy of teeth provides valuable information to the clinician that would help him achieve higher clinical success during endodontic therapy. Aims: To evaluate by computed tomography?the internal anatomy of mandibular second primary molars with respect to the number of canals, cross-sectional shape of canals, cross-section...

Variabilidad de las proporciones molares en poblaciones humanas: un abordaje empleando modelos del desarrollo y experimentales / Variability of molar proportions in human populations: insights from developmental models and experiments in mice

Directory of Open Access Journals (Sweden)

Lucas A. D´Addona

2016-03-01

Full Text Available Los datos sobre la variación dental interpoblacional y sobre los mecanismos que regulan el desarrollo dental aportados por estudios experimentales aún no han sido integrados en el contexto de investigaciones antropobiológicas. En este sentido, el presente trabajo se propone: a evaluar la consistencia entre la variación de las proporciones molares en poblaciones humanas que exhiben gran variación en el tamaño dental con las predicciones derivadas de un modelo de desarrollo dental de cascada inhibitoria, y b analizar el efecto de los factores sistémicos que controlan el crecimiento del organismo sobre las proporciones de los molares inferiores empleando cepas de Mus musculus. Se calcularon las áreas de los molares inferiores mediante los diámetros bucolingual y mesiodistal. La variación interpoblacional en las proporciones M2/M1 y M3/M1 fue concordante con las expectativas derivadas del modelo y la mayoría de los grupos exhibieron una tendencia a la reducción del tamaño en sentido antero-posterior. Asimismo, se observó una asociación significativa y positiva entre el área molar total y las proporciones molares. En los modelos experimentales la alteración del crecimiento por factores sistémicos (subnutrición proteica y reducción de la hormona de crecimiento resultó en la disminución del área molar total y cambios en las proporciones molares. Estos últimos, consistentes con el incremento del efecto inhibitorio en sentido antero-posterior. En conjunto, los resultados sugieren que la modificación de los factores sistémicos que regulan el área molar total podría conducir a cambios en la proporción de activadores-inhibidores y contribuir a la diferenciación interpoblacional en las proporciones molares. Palabras clave: Modelo de cascada inhibitoria; tamaño dental; aproximación experimental y comparativa Data on dental variation among human populations and the mechanisms regulating tooth development elucidated by

A finite element analysis of the stress distribution to the mandible from impact forces with various orientations of third molars*

Science.gov (United States)

Liu, Yun-feng; Wang, Russell; Baur, Dale A.; Jiang, Xian-feng

2018-01-01

Objective: To investigate the stress distribution to the mandible, with and without impacted third molars (IM3s) at various orientations, resulting from a 2000-Newton impact force either from the anterior midline or from the body of the mandible. Materials and methods: A 3D mandibular virtual model from a healthy dentate patient was created and the mechanical properties of the mandible were categorized to 9 levels based on the Hounsfield unit measured from computed tomography (CT) images. Von Mises stress distributions to the mandibular angle and condylar areas from static impact forces (Load I-front blow and Load II left blow) were evaluated using finite element analysis (FEA). Six groups with IM3 were included: full horizontal bony, full vertical bony, full 450 mesioangular bony, partial horizontal bony, partial vertical, and partial 450 mesioangular bony impaction, and a baseline group with no third molars. Results: Von Mises stresses in the condyle and angle areas were higher for partially than for fully impacted third molars under both loading conditions, with partial horizontal IM3 showing the highest fracture risk. Stresses were higher on the contralateral than on the ipsilateral side. Under Load II, the angle area had the highest stress for various orientations of IM3s. The condylar region had the highest stress when IM3s were absent. Conclusions: High-impact forces are more likely to cause condylar rather than angular fracture when IM3s are missing. The risk of mandibular fracture is higher for partially than fully impacted third molars, with the angulation of impaction having little effect on facture risk. PMID:29308606

Micro-computed Tomographic Analysis of Mandibular Second Molars with C-shaped Root Canals.

Science.gov (United States)

Amoroso-Silva, Pablo Andrés; Ordinola-Zapata, Ronald; Duarte, Marco Antonio Hungaro; Gutmann, James L; del Carpio-Perochena, Aldo; Bramante, Clovis Monteiro; de Moraes, Ivaldo Gomes

2015-06-01

The goal of the present study was to evaluate the morphometric aspects of the internal anatomy of the root canal system of mandibular second molars with C-shaped canals. Fifty-two extracted second mandibular molars with C-shaped canals, fused roots, and radicular grooves were selected from a Brazilian population. The samples were scanned with a micro-computed tomographic scanner at a voxel size of 19.6 μm. The root canal cross sections were recorded as C1, C2, C3, and C4 root canal configurations according to the modified Melton classification. Morphometric parameters, including the major and minor diameters of the root canals, the aspect ratio, the roundness, and the tridimensional configuration (merging, symmetric, and asymmetric), were evaluated. The 3-dimensional reconstruction images of the teeth indicated an even distribution within the sample. The analysis of the prevalence of the different cross-sectional configurations of the C-shaped molars revealed that these were predominantly of the C4 and C3 configurations (1 mm from the apex) and the C1 and C2 configurations in the cervical third. According to the morphometric parameters, the C1 and the distal aspect of the C2 configurations exhibited the lowest roundness values and higher values for the area, major diameter, and aspect ratio in the apical third. Mandibular molars with C-shaped root canals exhibited similar distributions of symmetric, asymmetric, and merging type canals. The C1 configuration and the distal aspect of the C2 configuration exhibited the highest area values, low roundness values, and large apical diameters. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Age of patient at the extraction of the third molar.

Science.gov (United States)

Kautto, A; Vehkalahti, M M; Ventä, I

2018-04-13

The purpose of this study was to assess the age of patients at the time of extraction of third molars. Our data included all routine and surgical extractions of third molars (n=8199 teeth) performed by general and specialist dentists of the public oral health services of the city of Helsinki over the period 2013-2014. Measurements included patient's age, gender, the identified third molar, the type of anaesthesia, the method of extraction, and the diagnosis at extraction. Patients' ages ranged from 10 to 99years. We found significant differences between younger and older age groups: third molar extractions occurred more often for women than for men below the age of 30years (Page of 40years, but the corresponding prevalences reversed after the age of 40years. Diagnoses at extraction differed between younger and older patients. We conclude that the treatment pattern of third molars at public health services varies greatly over a lifetime, and that a greater variety exists than had been reported previously from oral and maxillofacial units. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

The third molar as an age marker in adolescents: new approach to age evaluation.

Science.gov (United States)

Rozkovcova, Eva; Dostalova, Tatjana; Markova, Marie; Broukal, Zdenek

2012-09-01

Adolescence is a relatively short period between childhood and adulthood. It is very difficult to determine adulthood based on biological indicators. The third molar may be considered a potential age marker for the period between the ages of 16-21. Our study evaluated a set of 1700 panoramic radiographs of individuals aged between 5 and 21 years. Results confirmed the statistically significant difference in the course of third molars development. The mean deviation for individuals with one third molar agenesis is -0.98 years, for individuals with two third molars agenesis -1.89 years, and with three molars agenesis -3.28 years. Thus, the extent of the deviation is directly proportional to the number of unformed third molars. The calculation of age according to the mean of stages of all third molars could lead to the underestimation of age. No intergender differences were found. Age determination using third molars could be used for forensic purposes. © 2012 American Academy of Forensic Sciences.

[Application of hand-use ProTaper instruments in endodontic treatment of molar canals].

Science.gov (United States)

Ma, Sui-qi; Xie, Qian; Zhou, Yin-feng

2010-07-01

To evaluate the application of hand-use ProTaper instruments in endodontic treatment of molar canals. A total of 203 permanent molars were randomly divided into the experimental group (99 molars) and control group (104 molars) prepared by hand-use ProTaper instruments and standard stainless steel K-file, respectively. The molars in the two groups were obturated by cold lateral condensation technique. The root canal preparation and obturation were evaluated by radiograph, and the working time of preparation and post-operative emergencies were analyzed. The preparation time in the experimental group was obviously shorter than that in the control group (Phand-use ProTaper instruments may improve the effect of root canal treatment of the molars and shorten the working time and reduce the post-operative emergencies.

Supported molybdenum carbide for higher alcohol synthesis from syngas

DEFF Research Database (Denmark)

Wu, Qiongxiao; Christensen, Jakob Munkholt; Chiarello, Gian Luca

2013-01-01

Molybdenum carbide supported on active carbon, carbon nanotubes, and titanium dioxide, and promoted by K2CO3, has been prepared and tested for methanol and higher alcohol synthesis from syngas. At optimal conditions, the activity and selectivity to alcohols (methanol and higher alcohols) over...... carbide, while the selectivity to methanol follows the opposite trend. The effect of Mo2C loading on the alcohol selectivity at a fixed K/Mo molar ratio of 0.14 could be related to the amount of K2CO3 actually on the active Mo2C phase and the size, structure and composition of the supported carbide...... alcohols is obtained at a K/Mo molar ratio of 0.21 over the active carbon supported Mo2C (20wt%)....

The partial molar volume of BeSO4 in aqueous solutions

International Nuclear Information System (INIS)

Kuschel, F.; Seidel, J.

1981-01-01

The density of aqueous solutions of BeSO 4 has been measured as a function of the mole fraction in the range of 0.02487 x 10 -2 to 6.3082 x 10 -2 . From the results obtained the molar volume and partial molar volume have been calculated and the limiting value of the partial molar volume for Be 2+ was extrapolated in accordance with the Debye-Hueckel law

Fibrous epulis associated with impacted lower right third molar

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Ni Putu Mira Sumarta

2009-12-01

Full Text Available Background: Epulis or epulides are lesions associated with gingival tissues. Fibrous epulis is a type of hyperplastic fibrous tissue mass located at the gingival which is slow growing, painless, having same color as the oral mucosa and firm on palpation. Anterior regions of the oral cavity are the frequently affected sites as these areas are more prone to be affected by calculus deposition and poor plaque control due to frequent teeth malposition. Removal of any irritating factors and excision of the lesion are the usual treatments. Purpose: This case report presents a rare case of fibrous epulis which occurred in the posterior region of the oral cavity and associated with impacted lower third molar. Case: A case of fibrous epulis at the lower right third molar area of three months duration is presented. The mass was slow growing, painless and on examination it was a pedunculated mass overlying the unerupted lower right third molar, having same color with the oral mucosa and firm on palpation. Clinically, the lesion was diagnosed as fibrous epulis associated with impacted lower right third molar. Case management: The treatment were surgical excision of the epulis and removal of the lower right third molar. The histopathology result showed tissue with squamous epithelial lining, achanthotic fibrous connective tissue, mononuclear inflammatory cells and few capillaries without signs of malignancy. This is consistent with the diagnosis of fibrous epulis. Conclusion: Fibrous epulis, although frequently occurred at the anterior region of the oral cavity, may rarely grow at the area of lower third molar. This phenomenon supports the theory that epulis can grow on any surface of oral mucous membrane as long as local irritants are present.

Pendulum Therapy of Molar Distalization in Mixed Dentition.

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Patil, Raju Umaji; Prakash, Amit; Agarwal, Anshu

2016-01-01

Early and timely pedo-orthodontic treatment is aimed at eliminating the disturbances of skeletal or dentoalveolar development, to harmonize the stomatognathic system before the full eruption of all permanent teeth. The advantages of pendulum appliance are its minimal dependence on patient's compliance (child cooperation), ease of fabrication, onetime activation and adjustment of the springs if necessary to correct minor transverse and vertical molar positions. This article reports a successful treatment method of class II malocclusion with pendulum appliance in mixed dentition phase. Distalization of maxillary molar was done, followed by guidance of canine impaction orthodontically and other dental correction using 0.022 MBT appliances. Posttreatment results were stable and remarkable. How to cite this article: Patil RU, Prakash A, Agarwal A. Pendulum Therapy of Molar Distalization in Mixed Dentition. Int J Clin Pediatr Dent 2016;9(1):67-73.

Age estimation using development of third molars in South Indian population: A radiological study.

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Priyadharshini, K Indra; Idiculla, Jose Joy; Sivapathasundaram, B; Mohanbabu, V; Augustine, Dominic; Patil, Shankargouda

2015-05-01

To assess the estimation of chronological age based on the stages of third molar development following the eight stages (A-H) method of Demirjian et al. in Chennai population of South India. A sample consisting of 848 individuals (471 males and 377 females) aged between 14 and 30 years was randomly selected for the clinical evaluation and 323 orthopantomograms with clinically missing third molars were taken for radiological evaluation using Demirjian's method from a Chennai population of known chronological age and sex. Statistical analysis was performed using Pearson's Chi-square test and mean values were compared between the study groups using t-test or analysis of variance (ANOVA) followed by Tukey's highly significant difference (HSD). In the present study, P age of having clinically completely erupted maxillary third molars was 22.41 years in male subjects and 23.81 years in female subjects and that of mandibular third molars was 21.49 years in male subjects and 23.34 years in female subjects. Mandibular third molars were clinically missing more often in females than in males. Eruption of mandibular third molars was generally ahead of the emergence of maxillary third molars into the oral cavity. Third molar development between male and female subjects showed statistically significant differences at calcification stage F and stage G in maxillary third molars and stage F in mandibular third molars (P third molar eruption reached Demirjian's formation stages earlier in males than in females. It is suggested that in future studies, to increase the accuracy of age determination, indications of sexual maturity and ossification should also be evaluated in addition to third molar mineralization.

Analysis of mandibular second molars with fused roots and shallow radicular grooves by using micro-computed tomography.

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Amoroso-Silva, Pablo; De Moraes, Ivaldo Gomes; Marceliano-Alves, Marilia; Bramante, Clovis Monteiro; Zapata, Ronald Ordinola; Hungaro Duarte, Marco Antonio

2018-01-01

This study aimed to describe the morphological and morphometric aspects of fused mandibular second molars with radicular shallow grooves using micro-computed tomography (CT). Eighty-eight mandibular second molars with fused roots were scanned in a micro-CT scanner at a voxel size of 19.6 μm. After reconstruction, only molars without C-shaped roots and presenting shallow radicular grooves were selected. 30 molars were chosen for further analysis. Canal cross-sections were classified according to Fan's modified classification (C1, C2, C3, and C4) and morphometric parameters at the apical region, examination of accessory foramina and tridimensional configuration were evaluated. Three-dimensional reconstructions indicated a higher prevalence of merging type ( n = 22). According to Fan's modified classification, the C4 configuration was predominant in the 3 apical mm. Roundness median values revealed a more round-shaped canals at 3 mm (0.72) than at 2 (0.63) and 1 (0.61) mm from the apex. High values of major and minor diameters were observed in the canals of these evaluated sections. In addition, few accessory apical foramina were observed at 1 and 2 mm from the apex. The average distance between last accessory foramina and the anatomic apex was 1.17 mm. A less complex internal anatomy is found when a mandibular second molar presents fused roots with shallow radicular grooves. The merging type canal was frequently observed. Moreover, the C4 configuration was predominant at a point 3 mm from the apex and presented rounded canals, large apical diameters, and few accessory foramina. The cervical and middle thirds presented C3 and C1 canal configurations most frequently. A minor morphological complexity is found when fused mandibular second molars present shallow radicular grooves.

Estudio de volumen molar y refracción molar de miscelas de triglicéridos (triacetina, tributirina o tricaprilina) y alcoholes (etanol, 1-butanol o 1-hexanol)

OpenAIRE

Rodríguez Rodríguez, M.; Galán Vallejo, M.; Muñoz Cueto, María J.

1992-01-01

Values of molar refraction for every studied mixtures show linear plots versus molar fractions of triglyceride. Values of molar volume show this behaviour, but only for tributyrin-butanol or tricaprylin-butanol miscellas. However, in tributyrin-ethanol mixtures, volume contractions have been found, whereas triacetin-butanol and tributyrin-hexanol show volume expansions. These facts are related to the mode of being structured of the alcohol and triglyceride molecules in mixtures. A linea...

The prevalence and pattern of deciduous molar hypomineralization and molar-incisor hypomineralization in children from a suburban population in Nigeria

OpenAIRE

Temilola, Oluwaseyi Dada; Folayan, Morenike Oluwatoyin; Oyedele, Titus

2015-01-01

Background Molar Incisor Hypoplasia (MIH) and Deciduous Molar Hypoplasia (DMH) have significant impact on the quality of life of affected individuals. The objective of the study was to determine the prevalence, pattern and clinical presentation of MIH and DMH in children resident in Ile-Ife, Nigeria, and their association with sex and socioeconomic status of the children. Methods Information on age, sex and socioeconomic status was collected from 563 children aged 3 to 5?years and 8 to 10?yea...

In vitro fracture resistance of molar teeth restored with a short fibre-reinforced composite material.

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Fráter, Márk; Forster, András; Keresztúri, Márk; Braunitzer, Gábor; Nagy, Katalin

2014-09-01

The purpose of this in vitro study was to evaluate the efficiency of a short fibre-reinforced composite (SFRC) material compared to conventional composites when restoring class II. MOD cavities in molar teeth with different layering techniques. One hundred and thirty mandibular third molars were divided into 5 groups (n=26). Except for the control group (intact teeth), in all other groups MOD cavities were prepared. The cavities were restored by either conventional composite with horizontal and oblique layering or by SFRC with horizontal and oblique layering. The specimens were submitted to static fracture toughness test. Fracture thresholds and fracture patterns were evaluated. In general, no statistically significant difference was found in fracture toughness between the study groups, except for horizontally layered conventional composite restorations, which turned out to be significantly weaker than controls. However, SFRC yielded noticeably higher fracture thresholds and only obliquely applied SFRC restorations exhibited favourable fracture patterns above chance level. The application of SFRC did not lead to a statistically significant improvement of the fracture toughness of molar teeth with MOD cavities. Still, SFRC applied in oblique increments measurably reduces the chance of unrestorable fractures of molar teeth with class II MOD cavities. The restoration of severely weakened molar teeth with the use of SFRC combined with composite might have advantages over conventional composites alone. It was observed from the statistical data, that the application of SFRC with an oblique layering technique yielded not significantly but better fracture thresholds and more favourable fracture patterns than any other studied material/technique combination. Thus further investigations need to be carried out, to investigate the possible positive mechanical effects of SFRC. The application of the horizontal layering technique with conventional composite materials is inferior

Management of Unilaterally Impacted Permanent Mandibular First, Second and Third Molars

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Rohit Mehrotra

2014-01-01

Full Text Available This case report describes the treatment of a teenage patient with simultaneous impaction of all three right mandibular permanent molars. The impacted first and second mandibular molars were surgically exposed and orthodontically erupted into good alignment and occlusion while the impacted third molar in the same quadrant was extracted. The unique clinical presentation, various treatment alternatives, the decision making process in finalizing the treatment plan and its clinical implementation are discussed.

Assessment of low-dose radiotoxicity in microorganisms and higher organisms

International Nuclear Information System (INIS)

Obeid, Muhammad Hassan

2016-01-01

This work was dedicated to quantify and distinguish the radio- and chemitoxic effects of environmentally relevant low doses of uranium on the metabolism of microorganisms and multicellular organisms by a modern and highly sensitive microcalorimetry. In such low-dose regime, lethality is low or absent. Therefore, quantitative assays based on survival curves cannot be employed, particularly for multicellular organisms. Even in the case of microbial growth, where individual cells may be killed by particle radiation, classical toxicity assessments based on colony counting are not only extremely time-consuming but also highly error-prone. Therefore, measuring the metabolic activity of the organism under such kinds of conditions would give an extremely valuable quantitative measure of viability that is based on life cell monitoring, rather than determining lethality at higher doses and extrapolating it to the low dose regime. The basic concept is simple as it relies on the metabolic heat produced by an organism during development, growth or replication as an inevitable byproduct of all biochemical processes. A metabolic effect in this concept is defined as a change in heat production over time in the presence of a stressor, such as a heavy metal. This approach appeared to be particular versatile for the low dose regime. Thus, the thesis attempted in this case to measure the enthalpy production of a bacterial population as a whole to derive novel toxicity concepts. In the following chapters, an introduction about the properties of ionizing radiation will be briefly presented, in addition to a review about the isothermal calorimetry and its application in studying the bacterial growth. Later in chapter 2, the effect of uranium on the metabolic activity of three different bacterial strains isolated form a uranium mining waste pile together with a reference strain that is genetically related to them will be investigated. Due to the lack of published dedicated calibration

Assessment of low-dose radiotoxicity in microorganisms and higher organisms

Energy Technology Data Exchange (ETDEWEB)

Obeid, Muhammad Hassan

2016-01-11

This work was dedicated to quantify and distinguish the radio- and chemitoxic effects of environmentally relevant low doses of uranium on the metabolism of microorganisms and multicellular organisms by a modern and highly sensitive microcalorimetry. In such low-dose regime, lethality is low or absent. Therefore, quantitative assays based on survival curves cannot be employed, particularly for multicellular organisms. Even in the case of microbial growth, where individual cells may be killed by particle radiation, classical toxicity assessments based on colony counting are not only extremely time-consuming but also highly error-prone. Therefore, measuring the metabolic activity of the organism under such kinds of conditions would give an extremely valuable quantitative measure of viability that is based on life cell monitoring, rather than determining lethality at higher doses and extrapolating it to the low dose regime. The basic concept is simple as it relies on the metabolic heat produced by an organism during development, growth or replication as an inevitable byproduct of all biochemical processes. A metabolic effect in this concept is defined as a change in heat production over time in the presence of a stressor, such as a heavy metal. This approach appeared to be particular versatile for the low dose regime. Thus, the thesis attempted in this case to measure the enthalpy production of a bacterial population as a whole to derive novel toxicity concepts. In the following chapters, an introduction about the properties of ionizing radiation will be briefly presented, in addition to a review about the isothermal calorimetry and its application in studying the bacterial growth. Later in chapter 2, the effect of uranium on the metabolic activity of three different bacterial strains isolated form a uranium mining waste pile together with a reference strain that is genetically related to them will be investigated. Due to the lack of published dedicated calibration

Probabilidad de retención de segundos molares permanentes mandibulares (Estudio piloto

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Paulo Sandoval Vidal

Full Text Available Objetivos: Determinar la frecuencia del segundo molar mandibular permanente (MM2 con probabilidad de impactación, en un grupo de pacientes de Ortodoncia de Temuco, Chile. Método: Estudio de corte transversal, con muestra por conveniencia. Se revisaron 2095 fichas de individuos de ambos sexos, con ausencia de patología sindrómica. Los datos recolectados se obtuvieron de radiografías panorámicas. Se midió el ángulo del segundo molar con respecto al plano oclusal, la invasión distal del primer molar y la distancia entre distal del primer molar y el borde anterior de la rama mandibular. Resultados: El promedio de edad de los pacientes relevados fue de 10 años. Se observó un 1,43% de probabilidad de retención de MM2 (n=30; en promedio y el plano el ángulo MM2 resultó de 27° el izquierdo y 26° el derecho; la invasión de MM2 en distal del primer molar resultó de 1,5 mm; el ángulo entre MM2 y el planos oclusal es de 123°; la distancia entre la cara distal del primer molar y el borde anterior de la rama mandibular fue 13 mm. Conclusiones: Existe una baja prevalencia de segundos molares mandibulares permanentes con probabilidad de impactación. La invasión a la cara distal del primer molar fue mayor en pacientes con riesgo de impactación

Modified distal shoe appliance for premature loss of multiple deciduous molars: a case report.

Science.gov (United States)

Bhat, Prasanna Kumar; K, Navin H; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

2014-08-01

Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist's armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first permanent molar into place. Conventional design poses various limitations in cases of premature loss of multiple deciduous molars. Thus, it is required to modify the conventional designs according to the needs of the patient. This case report describes an innovative modification of distal shoe appliance in cases of premature loss of multiple deciduous molars. In the present case, modification of distal shoe space maintainer was advocated because of inadequate abutments caused due to multiple loss of deciduous molars. Bilateral design of distal shoe was planned for unilateral loss of deciduous molars.

Fusion or gemination? An unusual mandibular second molar

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Angela Jordão Camargo

2016-01-01

Full Text Available Fusion and gemination is not an uncommon finding and affected most primary dentition and the permanent maxillary incisors. These changes can develop a series of complication. A 11-year-old male presented radiography finding: an unusual mandibular second molar. A well-documented case brings a challenge for radiologists classify between fusion and gemination. In conclusion, this alteration although common in other regions, there are no case in the literature involving “second and third” molar.

A rare case of retained fourth molar teeth in maxilla and mandible. Case report

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Rahnama Mansur

2014-06-01

Full Text Available The study presents a case of the rarely occurring totally retained fourth molar teeth simultaneously in maxilla and mandible. The appearance of supernumerary teeth is a relatively uncommon dental anomaly and it is rare for patients to have impacted fourth molars in two quadrant. The aim of this work is to describe the presence of unilateral (right fourth molars in the maxilla and the mandible in a young female patient aged 24 years. Orthopantomogram revealed impacted lower third molars but also unerupted unilateral (right upper and lower fourth molars. Before orthodontic treatment, the patient was subsequently admitted for removal of third and fourth impacted upper and lower molars under local anesthesia.

Mandibular second molar with 3 mesial canals and a radix paramolaris

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N Ragavendran

2014-01-01

Full Text Available Mandibular first molar commonly has two roots, the mesial and the distal root. Surprisingly in some mandibular first molar has an unusual extra third root in between mesial and distal root. This extra root is the most commonly seen in lingual side and is called as radix entomolaris. If this extra root is seen on the buccal side, it is termed as radix paramolaris (RP, which is a very rare phenomenon. Recently, various case report studies has shown the presence of third canal in the mesial and distal roots of mandibular molars. They are named as middle mesial and middle distal canal, respectively. Here, we present a case report of mandibular second molar showing three canals in the mesial root and a RP.

An aegialodontid upper molar and the evolution of mammal dentition.

Science.gov (United States)

Lopatin, Alexey V; Averianov, Alexander O

2006-08-25

The most obvious key synapomorphy of the therian mammals is the tribosphenic pattern of their molars. Tribosphenic teeth are capable of both shearing and grinding, which substantially increase effectiveness of food processing and, in turn, permit evolution of a wide range of dietary specializations. Functional tribospheny developed repeatedly during mammalian evolution but was successful only in the Boreosphenida. The earliest stage in the development of boreosphenidan tribospheny has remained poorly understood, being documented only by lower molars of aegialodontids. Here, we report a known upper molar of an aegialodontid mammal, Kielantherium, from the Early Cretaceous of Mongolia.

Estudo in vitro da resistência ao cisalhamento da colagem direta de tubos ortodônticos em molares In vitro study of shear bond strength in direct bonding of orthodontic molar tubes

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Célia Regina Maio Pinzan Vercelino

2011-06-01

conducted with the purpose of evaluating whether direct bonding would benefit from the application of an additional layer of resin to the occlusal surfaces of the tube/tooth interface. METHODS: A sample of 40 mandibular third molars was selected and randomly divided into two groups: Group 1 - Conventional direct bonding, followed by the application of a layer of resin to the occlusal surfaces of the tube/ tooth interface, and Group 2 - Conventional direct bonding. Shear bond strength was tested 24 hours after bonding with the aid of a universal testing machine operating at a speed of 0.5mm/min. The results were analyzed using the independent t-test. RESULTS: The shear bond strength tests yielded the following mean values: 17.08 MPa for Group 1 and 12.60 MPa for Group 2. Group 1 showed higher statistically significant shear bond strength than Group 2. CONCLUSIONS: The application of an additional layer of resin to the occlusal surfaces of the tube/tooth interface was found to enhance bond strength quality of orthodontic buccal tubes bonded directly to molar teeth.

Standard molar enthalpies of formation and of sublimation of the terphenyl isomers

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Santos, Luis M.N.B.F.; Lima, Luis M. Spencer S.

2008-01-01

The standard (p 0 = 0.1 MPa) molar enthalpies of formation in the crystalline phases of ortho, meta and para-terphenyl isomers, at T = 298.15 K, were derived from the standard molar energies of combustion, measured by mini-bomb combustion calorimetry. The Knudsen mass-loss effusion technique was used to measure the dependence of the vapour pressure of the crystals with the temperature, thus deriving their standard molar enthalpies of sublimation by means of the Clausius-Clapeyron equation. Combining the standard molar enthalpies of formation and sublimation of the crystalline terphenyls, the standard molar enthalpies of formation in the gaseous state, at T = 298.15 K, were derived for the three isomers. Results are provided in a table. The results show small but detectable isomerization enthalpies between the terphenyls, indicating the following relative enthalpic stabilities: m- > p- ∼ o-terphenyl

Standard molar enthalpies of formation of three N-benzoylthiocarbamic-O-alkylesters

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Santos, Luis M.N.B.F.; Schroeder, Bernd; Dietze, Frank; Beyer, Lothar

2004-01-01

The standard (p 0 =0.1 MPa) molar enthalpies of combustion in oxygen of three crystalline N-benzoylthiocarbamic-O-alkylesters, PhCONHCSOR, R=Et (Hbtcee), n-Bu (Hbtcbe), n-Hex (Hbtche), were measured at T=298.15 K by rotating bomb calorimetry. The standard molar enthalpies of sublimation of the three compounds were measured using Calvet microcalorimetry. These values were used to derive the standard molar enthalpies of formation of the compounds in their crystalline and gaseous phases, respectively

Requirement of alveolar bone formation for eruption of rat molars

Science.gov (United States)

Wise, Gary E.; He, Hongzhi; Gutierrez, Dina L.; Ring, Sherry; Yao, Shaomian

2011-01-01

Tooth eruption is a localized event that requires a dental follicle (DF) to regulate the resorption of alveolar bone to form an eruption pathway. During the intra-osseous phase of eruption, the tooth moves through this pathway. The mechanism or motive force that propels the tooth through this pathway is controversial but many studies have shown that alveolar bone growth at the base of the crypt occurs during eruption. To determine if this bone growth (osteogenesis) was causal, experiments were designed in which the expression of an osteogenic gene in the DF, bone morphogenetic protein-6 (BMP6), was inhibited by injection of the 1st mandibular molar of the rat with an siRNA targeted against BMP6. The injection was followed by electroporation to promote uptake of the siRNA. In 45 first molars injected, eruption either was delayed or completely inhibited (7 molars). In the impacted molars, an eruption pathway formed but bone growth at the base of the crypt was greatly reduced as compared to the erupted first molar controls. These studies show that alveolar bone growth at the base of the crypt is required for tooth eruption and that BMP6 may be an essential gene for promoting this growth. PMID:21896048

Modified distal shoe appliance for the loss of a primary second molar: a case report.

Science.gov (United States)

Dhull, Kanika Singh; Bhojraj, Nandlal; Yadav, Shweta; Prabhakaran, Sheeja Devi

2011-01-01

Preservation of primary teeth until their normal exfoliation plays a crucial role in preventive and interceptive dentistry. Premature loss of the primary second molar prior to the eruption of the permanent first molar in the absence of the primary second molar can lead to mesial movement and migration of the permanent molar before and during its eruption. In such cases, an intra-alveolar type of space maintainer to guide the eruption of the permanent first molar is indicated. In certain cases, however, the conventional design is not practical. This paper describes a new design for distal shoe appliances in cases of primary second molar loss prior to the eruption of the permanent mandibular first molar.

Estudios físico-químicos de miscelas de aceites vegetales XIV. Volumen molar, refracción molar y viscosidad de disoluciones de estearato de metilo en ciciohexano, hexano, tetracloroetileno o tricloroetileno

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Muñoz Cueto, María J.

1991-02-01

Full Text Available In the miscelies studied, molar volume and molar refraction values show linear dependence with the molar fraction of methyl stearate. Viscosity values fit Hildebrand's modified equation, where the "V_o" parameter is a linear function of the molar fraction of methyl stearate. Regarding with this three physico-chemical properties, the mixtures studied behave like ideal mixtures of two organic liquids without ionization.

En todas las miscelas estudiadas los valores del volumen molar y de la refracción molar presentan variaciones lineales en función de la fracción molar de estearato de metilo. Los valores de viscosidad de las miscelas estudiadas se ajustan a la ecuación de fluidez de Hildebrand modificada, siendo su parámetro "V_o" función lineal de la fracción molar de estearato de metilo. En relación con estas tres características, el comportamiento de las miscelas estudiadas no difiere significativamente del correspondiente a una mezcla "ideal" de dos líquidos orgánicos sin ionizar.

Comparison and dosimetry of exposure dose to the patient in dental full mouth examination

International Nuclear Information System (INIS)

Kohirazawa, Hideo; Shinozima, Masayasu; Tokui, Mituru

1979-01-01

Comparisons of exposure dose to the patient of three types of oral x-ray apparatus (Dental, Panoramix, Orthopantomograph) were made. The exposure doses to the regions of incior, molar, eye (lens), thyroid gland, cervical spine and gonad were measured using Radocon II type dosimeter, T.L.D. and head phantom. Differences of exposure dose were found in three types of oral x-ray apparatus. After then improvement of aparture and investigation of sensitive materials and filter were made. Selection of the oral x-ray apparatus should not be done by exposure dose but by need of diagnosis. (author)

Molar Uprighting: A Considerable and Safe Decision to Avoid Prosthetic Treatment

Science.gov (United States)

Raveli, Taísa Boamorte; Raveli, Dirceu Barnabé; de Mathias Almeida, Kelei Cristina; Pinto, Ary dos Santos

2017-01-01

Background: Tipped lower molar over edentulous space is very common in orthodontics practice when adults seek treatment. The segmented arch technique features a predictable force system that provides a controlled release of force that can produce light and continuous tooth movement. Case Description: A female adult patient, who lost a permanent lower first molar, needed correction of the position of her permanent first molar place. Instead of making space for rehabilitation, it was closed after second molar uprighting and a balanced interdigitation was created without prosthetics. The patient was successfully treated with segmented arch technique using root correction spring activated with geometry VI to promote uprighting of a tipped molar and Niti spring coil to promote space closure. Practical Implications: Segmented arch technique is known to provide predictable light and continuous forces, which is very much indicated in adult treatment. There are several things to consider when orthodontically treating adult patients. Their periodontal conditions might not be ideal, less bone apposition may occur, and side effects of orthodontic tooth movement are expected. Thus, a predictable and controlled orthodontic treatment is needed. PMID:29114332

Unilateral maxillary molar distalization with zygoma-gear appliance.

Science.gov (United States)

Kilkis, Dogan; Bayram, Mehmet; Celikoglu, Mevlut; Nur, Metin

2012-08-01

The aim of this study was to present the orthodontic treatment of a 15-year-old boy with a unilateral maxillary molar distalization system, called the zygoma-gear appliance. It consisted of a zygomatic anchorage miniplate, an inner bow, and a Sentalloy closed coil spring (GAC International, Bohemia, NY). A distalizing force of 350 g was used during the distalization period. The unilateral Class II malocclusion was corrected in 5 months with the zygoma-gear appliance. The maxillary left first molar showed distalization of 4 mm with an inclination of 3°. The maxillary premolars moved distally with the help of the transseptal fibers. In addition, there were slight decreases in overjet (-0.5 mm) and maxillary incisor inclination (-1°), indicating no anchorage loss from the zygoma-gear appliance. Preadjusted fixed appliances (0.022 × 0.028-in, MBT system; 3M Unitek, Monrovia, Calif) were placed in both arches to achieve leveling and alignment. After 14 months of unilateral distalization with the zygoma-gear appliance and fixed appliances, Class I molar and canine relationships were established with satisfactory interdigitation of the posterior teeth. Acceptable overjet and overbite were also achieved. This article shows that this new system, the zygoma-gear appliance, can be used for unilateral maxillary molar distalization without anchorage loss. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Estudio de mezclas de disolventes orgánicos y triglicéridos de aceite de linaza o los ácidos grasos libres. I.- Volumen molar, refracción molar y viscosidad dinámica

Directory of Open Access Journals (Sweden)

Mantell Serrano, C.

1995-06-01

Full Text Available Measurements of molar volume, refraction index and dynamic viscosity in mixtures of fatty acids or triglycerides and trichloroethylene, tetrachloroethylene and hexane were realized. Temperature range studied was 278-313 K each 5 K. The relationship between molar volume and molar fraction show high correlation coefficient In fatty acids with trichloroethylene and tetrachloroethylene mixtures. On the other hand, hexane mixtures show little contractions of molar volume at low molar fractions. Triglyceride mixtures present important deviations with regard to the ideality of the molar volume. The adjusts obtained for the molar volume values versus temperature are acceptable, calculating the coefficients of thermal expansion of the studied mixtures. Equally, the adjust of the experimental results of viscosity for two prediction equations are studied: one of additive type and the other of parabolic type.

Se han realizado medidas del volumen molar, índice de refracción y viscosidad dinámica en el intervalo de temperatura de 278 K a 313 K cada 5 K, a mezclas de ácidos grasos o triglicéridos con tricloroetileno, tetracloroetileno y hexano. Las mezclas de ácidos grasos con tricloroetileno y tetracloroetileno, presentan unos altos coeficientes de correlación para los valores del volumen molar frente a la fracción molar, mientras que las mezclas con hexano, a fracciones molares bajas, manifiestan una pequeña contracción del volumen molar. Las mezclas de triglicéridos presentan importantes desviaciones con respecto a la Idealidad del volumen molar. Los ajustes obtenidos para los valores del volumen molar frente a la temperatura son aceptables, determinándose los valores del coeficiente de dilatación volumétrica a presión constante de las mezclas estudiadas. Igualmente se ha estudiado el ajuste de los resultados experimentales de viscosidad a dos ecuaciones de predicción: una del tipo aditiva y otra del tipo parabólico.

Endodontic treatment of a maxillary second molar with developmental anomaly: a case report.

Science.gov (United States)

Asgary, Saeed

2007-01-01

Fusion is a rare occurrence in molar teeth. The purpose of this rare case presentation is to describe the nonsurgical endodontic treatment of maxillary molar. A 28-year-old patient was referred for endodontic treatment of her chronic apical abscess of right maxillary second molar. In the clinical examination, a sinus tract adjacent to involved tooth and a small crown of supernumerary tooth fused to the buccal surface of the molar at gingival margin was observed. Endodontic treatment was decided for the involved molar for functional reason. Recall examination, a year after completion of endodontic and restorative treatments, showed the tooth was clinically asymptomatic and there was no radiographic lucency around the apical region.

Patterns of third-molar agenesis and associated dental anomalies in an orthodontic population.

Science.gov (United States)

Celikoglu, Mevlut; Bayram, Mehmet; Nur, Metin

2011-12-01

The aim of this study was to investigate the frequency of dental anomalies in orthodontic patients with different patterns of third-molar agenesis, comparing them with patients without third-molar agenesis. A sample of 374 patients with agenesis of at least 1 third molar was divided into 4 groups according to the third-molar agenesis pattern, and a control group of 98 patients without third-molar agenesis was randomly selected from the patient archives. Panoramic radiographs and cast models were used to determine the associated dental anomalies, such as hypodontia, hyperdontia, impaction, dilaceration, microdontia, ectopic eruption, transposition, and transmigration. The Pearson chi-square and Fisher exact tests were used to determine the differences in the distribution of the associated dental anomalies among the groups. The prevalence of agenesis of other teeth (11.2%, n = 42) was significantly greater in our study sample (groups 1-4) than in the control group (group 5) (4.1%, n = 4; P dental anomalies in patients with agenesis of 3 and 4 third molars compared with the control group. Permanent tooth agenesis, microdontia of maxillary lateral incisors, and total dental anomalies are more frequently associated with agenesis of 4 third molars than with the presence of third molars. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Elongational viscosity of narrow molar mass distribution polystyrene

DEFF Research Database (Denmark)

Bach, Anders; Almdal, Kristoffer; Rasmussen, Henrik Koblitz

2003-01-01

Transient and steady elongational viscosity has been measured for two narrow molar mass distribution polystyrene melts of molar masses 200 000 and 390 000 by means of a filament stretching rheometer. Total Hencky strains of about five have been obtained. The transient elongational viscosity rises...... above the linear viscoelastic prediction at intermediate strains, indicating strain hardening. The steady elongational viscosities are monotone decreasing functions of elongation rate. At elongation rates larger than the inverse reptation time, the steady elongational viscosity scales linearly...

Patients with Posttraumatic Stress Disorder with Comorbid Major Depressive Disorder Require a Higher Dose of Psychotropic Drugs.

Science.gov (United States)

Chiba, Hiromi; Oe, Misari; Uchimura, Naohisa

2016-01-01

Major depressive disorder (MDD) has been associated with stressful life events and with posttraumatic stress disorder (PTSD). PTSD and MDD comorbidity was also reported to be associated with greater symptom severity and lower levels of functioning. However, the characteristics of pharmacotherapy for PTSD with MDD are not fully understood. To understand this relationship, we conducted a retrospective review using medical charts at the Department of Neuropsychiatry, Kurume University Hospital. Information from 55 patients with PTSD was analyzed. Five cases were excluded after re-evaluation of the PTSD diagnosis. A higher rate of type II trauma was observed in the PTSD with MDD group (50.0%) than in the PTSD-only group [13.6%; χ(2) (1, n =50) = 7.26, p<0.01]. Patients with comorbid MDD were significantly older, had more severe PTSD symptomatology, and a longer duration of treatment. They also received higher doses of psychotropic drugs, regardless of the type (antidepressants, antipsychotics, benzodiazepines), than the PTSD-only group. Our results showed that comorbid MDD is associated with higher doses of psychotropic drugs, suggesting difficulties in treatment.

Endodontic Treatment of a Maxillary Second Molar with Developmental Anomaly: A Case Report

OpenAIRE

Asgary, Saeed

2007-01-01

Fusion is a rare occurrence in molar teeth. The purpose of this rare case presentation is to describe the nonsurgical endodontic treatment of maxillary molar. A 28-year-old patient was referred for endodontic treatment of her chronic apical abscess of right maxillary second molar. In the clinical examination, a sinus tract adjacent to involved tooth and a small crown of supernumerary tooth fused to the buccal surface of the molar at gingival margin was observed. Endodontic treatment was decid...

Conformal technique dose escalation in prostate cancer: improved cancer control with higher doses in patients with pretreatment PSA {>=} 10 ngm/ml

Energy Technology Data Exchange (ETDEWEB)

Hanks, G E; Lee, W R; Hanlon, A L; Kaplan, E; Epstein, B; Schultheiss, T

1995-07-01

Purpose: Single institutions and an NCI supported group of institutions have been investigating the value of dose escalation in patients with prostate cancer treated by conformal treatment techniques. Improvement in morbidity has been previously established, while this report identifies the pretreatment PSA level subgroups of patients who benefitted in cancer control from higher dose. Materials and Methods: We report actuarial bNED survival rates for 375 consecutive patients with known pretreatment PSA levels treated with conformal technique between 5/89 and 12/93. The whole pelvis was treated to 45 Gy in 25 fractions in all T2C,3, all Gleason 8, 9, 10 and all patients with pretreatment PSA {>=}20. The prostate {+-} seminal vesicles was boosted at 2.1 Gy/day to the center of the prostate to 65-79 Gy (65-69 N=50), 70-72.49 N=94, 72.5-74.9 N=82, 75-77.49 N=129 and {>=}77.5 N=20). The median followup is 21 mos with a range of 3 to 67 mos. The highest dose patients have the least followup, reducing the impact of the highest dose levels at this time. Patients are analyzed for the entire group divided at 71 Gy and at 73 Gy calculated at the center of the prostate. Each dose group is then subdivided by pretreatment PSA levels <10, 10-19.9, and {>=}20 ngm/ml and dose levels are compared within pretreatment PSA level group. bNED failure is defined as PSA {>=}1.5 ngm/ml and rising on two consecutive values. Results: Table 1 shows the bNED survival rates at 24 and 36 mos for all patients and the three pretreatment PSA level groups. For all patients pooled, there is an overall advantage to using doses {>=}71 Gy (64% vs 85% at 36 mo, p=.006) and {>=}73 Gy (71% vs 86% at 36 mo, p=.07). The subgroup of PSA <10 ngm/ml, however, shows no benefit in bNED survival when using doses over 71 Gy (90% vs 93% at 36 mo) or 73 Gy (91 vs 94% at 36 mo). The subgroup PSA 10 ngm/ml to 19.9 ngm/ml shows improved cancer control when using doses over 71 Gy (61% vs 88% at 36 mo, p=.03) and over 73

Standard molar enthalpies of formation of 2-, 3- and 4-cyanobenzoic acids

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Amaral, Luisa M.P.F.; Boaventura, Cristina R.P.; Gomes, Jose R.B.

2008-01-01

The standard (p 0 = 0.1 MPa) molar enthalpies of formation of 2-, 3- and 4-cyanobenzoic acids were derived from their standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpies of sublimation of 2- and 3-cyanobenzoic acids. The standard molar enthalpies of formation of the three compounds, in the gaseous phase, at T = 298.15 K, have been derived from the corresponding standard molar enthalpies of formation in the condensed phase and standard molar enthalpies for phase transition. The results obtained are -(150.7 ± 2.0) kJ . mol -1 , -(153.6 ± 1.7) kJ . mol -1 and -(157.1 ± 1.4) kJ . mol -1 for 2-cyano, 3-cyano and 4-cyanobenzoic acids, respectively. Standard molar enthalpies of formation were also estimated by employing two different methodologies: one based on the Cox scheme and the other one based on several different computational approaches. The calculated values show a good agreement with the experimental values obtained in this work

Estimation of effective dose from limited cone beam X-ray CT examination

Energy Technology Data Exchange (ETDEWEB)

Iwai, Kazuo; Arai, Yoshinori; Hashimoto, Koji [Nihon Univ., Tokyo (Japan). School of Dentistry; Nishizawa, Kanae

2000-12-01

The limited cone beam X-ray CT (Ortho-CT) was developed on the basis of multi-functional panoramic apparatus, SCANORA (Soredex Co. Helsinki Finland). The imaging intensifier (I.I.) was built in this apparatus as a X-ray detection device instead of X-ray film. The signal provided from I.I. was converted from analog into digital by an analog-digital converter and image reconstitution was done as a three-directional image of the dimensions 3.8 cm of width, 3.0 cm height and 3.8 cm depth with the personal computer. The 3DX Multi image micro CT'' (3DX) was developed along similar lines by MORITA Co., Ltd. (Kyoto, JAPAN). In this study, the stochastic effect on organ and tissue caused by examinations using Ortho-CT and 3DX was measured. The effective dose was estimated according to the recommendation of ICRP60 and was compared with those of panoramic radiography and computed tomography. The irradiation conditions were as follows: 85 kV, 10 mA with the filtration of 3 mmAl and added 1 mmCu for Ortho-CT, and 80 kV, 2 mA and the filtration of 3.1 mmAL for 3DX. The measurement of organ and tissue dose was performed using an anthropomorphic Rando woman phantom (Alderson Research Laboratories Co., Stanfora, CN), as well as by using two different type of thermoluminescent dosimeter (TLD); Panasonic UD-170A (BeO) and UD-110S (CaSO{sub 4}: Tm). The UD-170A was for dose measurement of the inner useful X-ray beams, while the UD-110S was for outer beams. The measured organ and tissue were those recommended with ICRP60 (gonad, breast, bone marrow, lung, thyroid gland, esophagus, stomach, colon, liver, bladder, skin, brain, thymus, adrenal, kidney, spleen, pancrease, upper large intestine, uterus, eyes and major salivary gland). The imaging by Orhto-CT was made in the left maxillary 1st molar, left mandibular 1st molar and temporomandibular joint. 3DX measurement was made in the maxillary incisor region and middle ear regions other than the regions mentioned above. The skin

C-shaped root canal in a maxillary first molar: a case report.

Science.gov (United States)

Yilmaz, Z; Tuncel, B; Serper, A; Calt, S

2006-02-01

This case report presents an unusual C-shaped root canal system in a maxillary first molar tooth. Although C-shaped root canals are most frequently seen in the mandibular second molar, they may also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. The present case describes a C-shaped canal in the buccal root of a maxillary first molar. The endodontic access cavity displayed two canal orifices, one leading to the canal system in the buccal root, the other into the palatal root canal system. In the buccal root, what appeared to be the mesial and distal canals joined to form a single C-shaped canal. --Careful examination of radiographs and the internal anatomy of teeth is essential.-- The location and morphology of root canals should be identified at high magnification under the microscope.

Use of palatally inserted mini-screw for upper molar distalization: A case series

Directory of Open Access Journals (Sweden)

Valliollah Arash

2015-09-01

Full Text Available  Abstract Reports have shown that molars can be distalized successfully with virtually no orthodontic anchorage loss with an intraosseous anchorage, even with fully erupted second molars. The purpose of this study was evaluating the effects of mini-screws as skeletal anchorage for upper molar distalization. In this case series, three patients needing maxillary first molar distalization, were selected. mini-screw was inserted in the anterior part of the palate. The screws were anchored to the first premolars by transpalatal arch and immediately loaded (150-160 g by 0.018-inch arch-wire and steel open-coil spring to distalize maxillary molars. The skeletal and dental changes were measured on cephalograms obtained before and after distalization. The amount of first molar distalization in the patients was 4 mm with 2°of tipping, 4 mm with 5°of tipping, and 3.5 mm with 2°of tipping respectively. Upper incisors and first premolars were stable during distalization.       

Broader Considerations of Higher Doses of Donepezil in the Treatment of Mild, Moderate, and Severe Alzheimer's Disease

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Camryn Berk

2012-01-01

Full Text Available Donepezil, a highly selective acetylcholinesterase inhibitor (AChEI, is approved as a symptomatic treatment mild, moderate, and severe Alzheimer's disease (AD. Donepezil exerts its treatment effect through multiple mechanisms of action including nicotinic receptor stimulation, mitigation of excitotoxicity, and influencing APP processing. The use of donepezil at higher doses is justified given the worsening cholinergic deficit as the disease advances. Donepezil has been investigated in several clinical trials of subjects with moderate-to-severe AD. While the side effects are class specific (cholinergically driven, demonstrable benefit has been shown at the 10 mg dose and the 23 mg doses. Here, we review the clinical justification, efficacy, safety, and tolerability of use of donepezil in the treatment of moderate-to-severe AD.

Molar incisor hypomineralisation: clinical management of the young patient.

LENUS (Irish Health Repository)

Daly, Dympna

2009-04-01

Molar incisor hypomineralisation (MIH) is a common developmental condition resulting in enamel defects in first permanent molars and permanent incisors. It presents at eruption of these teeth. Early diagnosis is essential since rapid breakdown of tooth structure may occur, giving rise to acute symptoms and complicated treatment. The purpose of this article is to review MIH and illustrate its clinical management in young children.

MMP20 Overexpression Disrupts Molar Ameloblast Polarity and Migration.

Science.gov (United States)

Shin, M; Chavez, M B; Ikeda, A; Foster, B L; Bartlett, J D

2018-02-01

Ameloblasts responsible for enamel formation express matrix metalloproteinase 20 (MMP20), an enzyme that cleaves enamel matrix proteins, including amelogenin (AMELX) and ameloblastin (AMBN). Previously, we showed that continuously erupting incisors from transgenic mice overexpressing active MMP20 had a massive cell infiltrate present within their enamel space, leading to enamel mineralization defects. However, effects of MMP20 overexpression on mouse molars were not analyzed, although these teeth more accurately represent human odontogenesis. Therefore, MMP20-overexpressing mice ( Mmp20 +/+ Tg + ) were assessed by multiscale analyses, combining several approaches from high-resolution micro-computed tomography to enamel organ immunoblots. During the secretory stage at postnatal day 6 (P6), Mmp20 +/+ Tg + mice had a discontinuous ameloblast layer and, unlike incisors, molar P12 maturation stage ameloblasts abnormally migrated away from the enamel layer into the stratum intermedium/stellate reticulum. TOPflash assays performed in vitro demonstrated that MMP20 expression promoted β-catenin nuclear localization and that MMP20 expression promoted invasion through Matrigel-coated filters. However, for both assays, significant differences were eliminated in the presence of the β-catenin inhibitor ICG-001. This suggests that MMP20 activity promotes cell migration via the Wnt pathway. In vivo, the unique molar migration of amelogenin-expressing ameloblasts was associated with abnormal deposition of ectopic calcified nodules surrounding the adherent enamel layer. Enamel content was assessed just prior to eruption at P15. Compared to wild-type, Mmp20 +/+ Tg + molars exhibited significant reductions in enamel thickness (70%), volume (60%), and mineral density (40%), and MMP20 overexpression resulted in premature cleavage of AMBN, which likely contributed to the severe defects in enamel mineralization. In addition, Mmp20 +/+ Tg + mouse molar enamel organs had increased levels

Space loss following premature loss of primary second molars.

Science.gov (United States)

Alnahwi, Hassan H; Donly, Kevin J; Contreras, Claudia I

2015-01-01

This study was designed to evaluate the amount of space loss (SL) caused by premature loss of primary second molars, determine whether the eruption status of permanent first molars is an important factor in the amount of SL, and evaluate the effectiveness of space maintainers (SMs) in SL prevention. SL associated with 100 prematurely extracted primary second molars was evaluated in 87 healthy patients. Teeth were divided into groups based on the use of SMs (36 with SM and 64 without SM). Bitewing and periapical radiographs taken before extraction and 6, 12, 24, 36, and 48 months after extraction were used to determine the amount of SL. Not every patient attended every recall appointment, so the sample size varied at different evaluation times. The most significant amount of SL occurred in the first 12 months after extraction. In patients who did not use an SM, at 6 months there was a mean SL of 2.12 mm (SD, 1.65 mm) and at 12 months there was a mean of 4.02 mm (SD, 1.65), with significantly more SL in the first 6 months (P 0.05). When patients without an SM were grouped by the eruption status of the permanent first molar, there was significantly more SL in the groups with unerupted first molars than there was in the groups with erupted first molars at both 6 months (P < 0.001) and 12 months (P < 0.05). At both 6 and 12 months, the amount of SL in patients who had an SM (n = 13 and n = 14, respectively) was not significantly different from the amount of SL in those who did not have an SM (n = 33 and n = 23, respectively). SMs should be placed as soon as possible following tooth extraction to prevent undue SL. Placement of an SM a year or more after extraction has minimal benefit, since most SL takes place within the first year. SL does occur even when SMs are used.

A combined experimental and computational investigation of excess molar enthalpies of (nitrobenzene + alkanol) mixtures

International Nuclear Information System (INIS)

Neyband, Razieh Sadat; Zarei, Hosseinali

2015-01-01

Highlights: • Excess molar enthalpies for the binary mixtures of nitrobenzene + alkanols mixtures were measured. • The infinite dilution excess partial molar enthalpies were calculated using the ab initio methods. • The PCM calculations were performed. • The computed excess partial molar enthalpies at infinite dilution were compared to experimental results. - Abstract: Excess molar enthalpies (H m E ) for the binary mixtures of {(nitrobenzene + ethanol), 1-propanol, 2-propanol, 1-butanol and 2-butanol} have been measured over the entire composition range at ambient pressure (81.5 kPa) and temperature 298 K using a Parr 1455 solution calorimeter. From the experimental results, the excess partial molar enthalpies (H i E ) and excess partial molar enthalpies at infinite dilution (H i E,∞ ) were calculated. The excess molar enthalpies (H m E ) are positive for all {nitrobenzene (1) + alkanol (2)} mixtures over the entire composition range. A state-of-the-art computational strategy for the evaluation of excess partial molar enthalpies at infinite dilution was followed at the M05-2X/6-311++G ∗∗ level of theory with the PCM model. The experimental excess partial molar enthalpies at infinite dilution have been compared to the computational data of the ab initio in liquid phase. Integrated experimental and computational results help to clarify the nature of the intermolecular interactions in {nitrobenzene (1) + alkanol (2)} mixtures. The experimental and computational work which was done in this study complements and extends the general research on the computation of excess partial molar enthalpy at infinite dilution of binary mixtures

Roentgenographic studies on the growth and development of lower third molars in Korean female

Energy Technology Data Exchange (ETDEWEB)

Lim, Hyoung Soon; Lee, Sung Woo [Department of Dental Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

1976-11-15

The author obtained the following results through the studies on 1012 roentgenograms of lower third molar regions of Korean female; 1. The rate of presence of lower third molars was 78.9 percent. 2. The period that crowns of lower third molars become completed was 16.1 years. 3. The period that completion of apices of lower third molars become completed was over 27 years.

Molar Volume Analysis of Molten Ni-Al-Co Alloy by Measuring the Density

Institute of Scientific and Technical Information of China (English)

XIAO Feng; FANG Liang; FU Yuechao; YANG Lingchuan

2004-01-01

The density of molten Ni-Al-Co alloys was measured in the temperature range of 1714～1873K using a modified pycnometric method, and the molar volume of molten alloys was analyzed. The density of molten Ni-Al-Co alloys was found to decrease with increasing temperature and Co concentration in alloys. The molar volume of molten Ni-Al-Co alloys increases with increasing Co concentration in alloys. The molar volume of molten Ni-Al-Co alloys shows a negative deviation from the linear molar volume.

A Phase I Study of the Safety and Pharmacokinetics of Higher-Dose Icotinib in Patients With Advanced Non-Small Cell Lung Cancer.

Science.gov (United States)

Liu, Jian; Wu, Lihua; Wu, Guolan; Hu, Xingjiang; Zhou, Huili; Chen, Junchun; Zhu, Meixiang; Xu, Wei; Tan, Fenlai; Ding, Lieming; Wang, Yinxiang; Shentu, Jianzhong

2016-11-01

This phase I study evaluated the maximum tolerated dose, dose-limiting toxicities, safety, pharmacokinetics, and efficacy of icotinib with a starting dose of 250 mg in pretreated, advanced non-small cell lung cancer patients. We observed a maximum tolerated dose of 500 mg with a favorable pharmacokinetics profile and antitumor activity.These findings provide clinicians with evidence for application of higher-dose icotinib. Icotinib, an oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has shown favorable tolerability and antitumor activity at 100-200 mg in previous studies without reaching the maximum tolerated dose (MTD). In July 2011, icotinib was approved by the China Food and Drug Administration at a dose of 125 mg three times daily for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) after failure of at least one platinum-based chemotherapy regimen. This study investigated the MTD, tolerability, and pharmacokinetics of higher-dose icotinib in patients with advanced NSCLC. Twenty-six patients with advanced NSCLC were treated at doses of 250-625 mg three times daily The EGFR mutation test was not mandatory in this study. Twenty-four (92.3%) of 26 patients experienced at least one adverse event (AE); rash (61.5%), diarrhea (23.1%), and oral ulceration (11.5%) were most frequent AEs. Dose-limiting toxicities were seen in 2 of 6 patients in the 625-mg group, and the MTD was established at 500 mg. Icotinib was rapidly absorbed and eliminated. The amount of time that the drug was present at the maximum concentration in serum (T max ) ranged from 1 to 3 hours (1.5-4 hours) after multiple doses. The t 1/2 was similar after single- and multiple-dose administration (7.11 and 6.39 hours, respectively). A nonlinear relationship was observed between dose and drug exposure. Responses were seen in 6 (23.1%) patients, and 8 (30.8%) patients had stable disease. This study demonstrated that higher-dose

Maxillary First Molars with 2 Distobuccal Canals: A Case Series.

Science.gov (United States)

Fogel, Howard M; Cunha, Rodrigo Sanches

2017-11-01

An appreciation of the anatomic complexity of the root canal system is essential at every step of endodontic treatment. Endodontic treatment of teeth with unusual root canal anatomy presents a unique challenge. Eight patients underwent nonsurgical root canal treatment of 3-rooted maxillary first molars in a specialty endodontic private practice. Four cases of Weine type II and 4 cases of Weine type III canal configurations in the distobuccal root of maxillary first molars were presented.This article highlighted an uncommon anatomic variation of 2 canals in the distobuccal root of the maxillary first molar. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

C-reactive protein a better indicator of inflammation after third molar ...

African Journals Online (AJOL)

operative pain and pre-operative levels of C-reactive and post-operative pain and swelling in impacted third molar surgery. Materials and Methods: In this prospective study subjects were patients indicated for mandibular third molar extraction.

Two-rooted maxillary first molars with two canals: a case series.

Science.gov (United States)

Shakouie, Sahar; Mokhtari, Hadi; Ghasemi, Negin; Gholizadeh, Seddigheh

2013-01-01

Thorough understanding of the anatomic and internal morphology of a root canal system is absolutely essential for the success of endodontic treatment. Since permanent maxillary first molars have shown variation in internal anatomy, morphology, this tooth has been reviewed extensively. Presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. In this report, three cases are presented, which involve the root canal treatment of maxillary first molars with fusion of the two buccal roots.

Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars.

Science.gov (United States)

Abarca, J; Zaror, C; Monardes, H; Hermosilla, V; Muñoz, C; Cantin, M

2014-06-01

Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3-5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24-0.33 mm in maxillary first molars and between 0.25-0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully.

Morphology of the Physiological Apical Foramen in Maxillary and Mandibular First Molars

Science.gov (United States)

Abarca, J.; Zaror, C.; Monardes, H.; Hermosilla, V.; Muñoz, C.; Cantin, M.

2015-01-01

SUMMARY Information regarding the anatomy of the physiological apical foramen is limited. Knowing its diameter and shapes contributes to clinical work, specifically to the cleaning and shaping of the apical third. The aim of this ex vivo study was to determine the minimum and maximum diameters and shape of the physiological apical foramen in the roots of maxillary and mandibular first molars. A descriptive study was conducted on 89 recently extracted first molars. Roots 3–5 mm from the apex were sectioned and prepared for analysis at 40× magnification. The minimum and maximum diameters of each physiological foramen were measured using the program Motic Images plus 2.0 ML. The shape of the foramina, classified as round, oval or irregular, was determined by the difference between the maximum and minimum diameters. A total of 174 physiological foramina were analyzed. The average of the minimum and maximum diameters was between 0.24–0.33 mm in maxillary first molars and between 0.25–0.33 mm in mandibular first molars. In maxillary molars, the most common shape of the foramen was oval (50%), then irregular (32%), then round (18%). In mandibular molars, the oval shape was also the most frequent (59%), followed by irregular (23%) and round (18%). The findings of this study regarding the morphology of physiological apical foramina in first molars make it easier for the operator to choose the appropriately-sized instruments to perform endodontic therapy successfully. PMID:25937698

Dilatometric measurement of the partial molar volume of water sorbed to durum wheat flour.

Science.gov (United States)

Hasegawa, Ayako; Ogawa, Takenobu; Adachi, Shuji

2013-01-01

Moisture sorption isotherms were measured at 25 °C for untreated, dry-heated and pre-gelatinized durum wheat flour samples. The isotherms could be expressed by the Guggenheim-Anderson-de Boer equation. The amount of water sorbed to the untreated flour was highest for low water activity, with water sorbed to the pre-gelatinized and dry-heated flour samples following. The dry-heated and pregelatinized flour samples exhibited the same dependence of the moisture content on the partial molar volume of water at 25 °C as the untreated flour. The partial molar volume of water was ca. 9 cm(3)/mol at a moisture content of 0.03 kg-H2O/kg-d.m. The volume increased with increasing moisture content, and reached a constant value of ca. 17.5 cm(3)/mol at a moisture content of 0.2 kg-H2O/kg-d.m. or higher.

Relationship of third molar movement during orthodontic treatment and root angulation

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Morteza Oshagh

2012-01-01

Conclusion: The relation between the amount of third molar movement and its root angulation was not statistically significant. Therefore movement of third molars during orthodontic treatment should not be assumed as an etiologic factor of root angulations.

Histopathologic Evaluation of Follicular Tissues Associated with Impacted Third Molars

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M. Khorasani

2008-06-01

Full Text Available Objective: The aim of the present study was to histopathologically evaluate follicular tissues of third molars with pericoronal radiolucenciesof less than 2 millimeters.Materials and Methods: In this descriptive analytic study, 100 impacted third molars with normal follicular spaces were removed and their pericoronaltissues submitted for histopathologic examination. Different characteristicsof the epithelium and connective tissue were evaluated in all cases. Statisti-cal analysis was performed using chi square and Mann-Whitney tests.Results: In our study sample, 74% of the patients were female and 26% were male, ranging in age from 13 to 54 years (mean, 25.3 years. Lining epithelium was observed in 69% of the specimens of which 31%, 23% and 14% was cuboidal, squamous and columnar, respectively. A significant re-lationship was found between the presence of squamous epithelium and pa-tient age (P<0.05. Nonspecific chronic inflammation was the only patho-logic finding observed in 44% of the specimens. Inflammation was signifi-cantly associated with age and squamous metaplasia (P<0.05.Conclusion: Considering that pathologic lesions were not observed in anyof the studied cases, unerupted third molars should not be removed unless there is a clinical indication to do so, or in case the impacted molar shows evidence of pathological changes. Follow-up is suggested for asympto-matic impacted third molars.

Lingual nerve injury following surgical removal of mandibular third molar

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Abduljaleel Azad Samad

2017-12-01

Full Text Available Background and objective: The close proximity of lingual nerve in relation to the lingual cortical bone of the posterior mandibular third molar is clinically important because lingual nerve may be subjected to trauma during surgical removal of the impacted lower third molar. This prospective study aimed to evaluate the incidence of lingual nerve paresthesia following surgical removal of mandibular third molar in College of Dentistry, Hawler Medical University. Methods: A total of 116 third molars surgery were carried out under local anesthesia for 116 patients for removal of lower mandibular teeth Using Terence Ward's incision made in all cases, and after that, the buccal flap was reflected, lingual tissues had been retracted during bone removal with a periosteal elevator. The sensory disturbance was evaluated on the 7th postoperative day by standard questioning the patients: “Do you have any unusual feeling in your tongue, lingual gingiva and mucosa of the floor of the mouth?" Results: One patient experienced sensory disturbance, the lingual nerve paresthesia incidence was 0.9% as a transient sensory disturbance, while no patient of permanent sensory disturbance. Conclusion: The incidence of injury to the lingual nerve can be minimized by careful clinical evaluation, surgeon’s experience, surgical approach and knowledge about anatomical landmarks during surgical removal of an impacted lower third molar tooth.

Dose sculpting with generalized equivalent uniform dose

International Nuclear Information System (INIS)

Wu Qiuwen; Djajaputra, David; Liu, Helen H.; Dong Lei; Mohan, Radhe; Wu, Yan

2005-01-01

With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this study was to investigate the effectiveness of gEUD optimization to fine tune the dose distributions of IMRT plans. We analyzed the effect of gEUD-based optimization parameters on plan quality. The objective was to determine whether dose distribution to selected structures could be improved using gEUD optimization without adversely altering the doses delivered to other structures, as in sculpting. We hypothesized that by carefully defining gEUD parameters (EUD 0 and n) based on the current dose distributions, the optimization system could be instructed to search for alternative solutions in the neighborhood, and we could maintain the dose distributions for structures already satisfactory and improve dose for structures that need enhancement. We started with an already acceptable IMRT plan optimized with any objective function. The dose distribution was analyzed first. For structures that dose should not be changed, a higher value of n was used and EUD 0 was set slightly higher/lower than the EUD value at the current dose distribution for critical structures/targets. For structures that needed improvement in dose, a higher to medium value of n was used, and EUD 0 was set to the EUD value or slightly lower/higher for the critical structure/target at the current dose distribution. We evaluated this method in one clinical case each of head and neck, lung and prostate cancer. Dose volume histograms, isodose distributions, and relevant tolerance doses for critical structures were used for the assessment. We found that by adjusting gEUD optimization parameters, the dose distribution could be improved with only a few iterations. A larger value of n could lead to

Standard molar enthalpies of formation of 2-, 3-, and 4-piperidinomethanol isomers

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Cabral, Joana I.T.A.

2006-01-01

The standard (p o =0.1MPa) molar energies of combustion in oxygen of 2-piperidinemethanol, 3-piperidinemethanol, and 4-piperidinemethanol, all in the crystalline phase, were measured, at T=298.15K, by static bomb calorimetry. These values were used to derive the standard molar enthalpies of combustion and the standard molar enthalpies of formation, in the condensed phase, for these compounds. Further, the standard molar enthalpies of sublimation, at T=298.15K, of these three piperidinomethanol isomers were determined by Cavet microcalorimetry. The combustion calorimetry results together with those from the Calvet microcalorimetry, were used to derive the standard molar enthalpies of formation, at T=298.15K, in the gaseous phase, of the three piperidinemethanol studied. -Δ c H m o (cr)Δ cr g H m o kJ.mol -1 kJ.mol -1 2-Piperidinemethanol3890.70+/-0.9293.02+/-0.503- Piperidinemethanol3895.3+/-1.195.9+/-1.44-Piperidinemethanol3891.3+/- 1.198.31+/-0.69

Variant root morphology of third mandibular molar in normal and ...

African Journals Online (AJOL)

The mandibular third molar poses a challenge to dental surgeons due to it's unpredictable morphology which leads to increased difficulty during its extraction. The root morphology of the third molar is considered to be the most variable in the human dentition. The study aims to document these variations which will be useful ...

Management of periodontally compromised mandibular molar with Hemisectioning: A case report

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Bandu Napte

2014-01-01

Full Text Available Introduction: Hemisection involves sectioning of a periodontally involved mandibular molar so as to remove the involved root and save the remaining tooth. This procedure helps in saving a tooth which otherwise would have been deemed for extraction. Hemisection refers to removal or separation of root with its accompanying crown portion of two-rooted teeth, most commonly mandibular molars. Method: In this case report, an advanced Endo-Perio lesion on a left mandibular first molar was successfully treated by root-canal treatment and hemisection. This procedure helps preserve the tooth structure, alveolar bone and promote cost savings over other treatment options. Conclusion: Hemisection is a treatment option for saving a mandibular molar which is in advanced stage of periodontal disease of one root. Removal of the affected root will help in retaining the remaining tooth structure.

Molar incisor hypomineralization: Considerations about treatment in a controlled longitudinal case

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Daniela Cristina de Oliveira

2015-01-01

Full Text Available Molar incisor hypomineralization (MIH is a defect in the tooth enamel of systemic origin and may affect one or all four first permanent molars frequently associated with the permanent incisors. This case reports a 7-year-old child with severe MIH in the permanent molars associated with tooth decay and intense pain. In the first stage of treatment, therapy was performed with fluoride varnish and restoration with glass ionomer cement (GIC. After 6 years of clinical and radiographic follow-up, the restorations presented wear and fractures on the margins, indicating their replacement with composite resin. Severe cases of MIH in the early permanent molars can be treated with varnish and GIC to restore the patient′s comfort and strengthen the hypomineralized dental structures. The clinical and radiographic monitoring frequently indicated when the restoration with composite resin should be performed.

Approximal morphology as predictor of approximal caries in primary molar teeth

DEFF Research Database (Denmark)

Cortes, A; Martignon, S; Qvist, V

2018-01-01

consent was given, participated. Upper and lower molar teeth of one randomly selected side received a 2-day temporarily separation. Bitewing radiographs and silicone impressions of interproximal area (IPA) were obtained. One-year procedures were repeated in 52 children (84%). The morphology of the distal...... surfaces of the first molar teeth and the mesial surfaces on the second molar teeth (n=208) was scored from the occlusal aspect on images from the baseline resin models resulting in four IPA variants: concave-concave; concave-convex; convex-concave, and convex-convex. Approximal caries on the surface...

Prevalence and Pattern of Third Molar Impaction; A retrospective study of radiographs in Oman

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Samira M. Al-Anqudi

2014-08-01

Full Text Available Objectives: The aim of this retrospective study was to investigate the prevalence and pattern of third molar impaction in patients between 19‒26 years old attending Sultan Qaboos University Hospital (SQUH in Muscat, Oman. Methods: The study reviewed 1,000 orthopantomograms (OPGs of patients attending the Oral Health Department of SQUH between October 2010 and April 2011. Patients were evaluated to determine the prevalence of third molar impaction, angulation, level of eruption and associated pathological conditions. Results: Of the study population, 543 (54.3% OPGs showed at least one impacted third molar. The total number of impacted molars was 1,128. The most common number of impacted third molars was two (41%. The most common angulation of impaction in the mandible was the mesioangular (35% and the most common level of impaction in the mandible was level A. Of the 388 bilateral occurrences of impacted third molars, 377 were in the mandible. There was no significant difference in the frequency of impaction between the right and left sides of both jaws. Pathological conditions associated with impacted lower third molars were found in 18%, of which 14% were associated with a radiographic radiolucency of more than 2.5 mm, and 4% of impacted lower third molars were associated with dental caries. Conclusion: This study found that more than half of Omani adult patients ranging in age from 19‒26 years had at least one impacted third molar.

Dental and skeletal changes after intraoral molar distalization with sectional jig assembly.

Science.gov (United States)

Gulati, S; Kharbanda, O P; Parkash, H

1998-09-01

The present study was conducted on 10 subjects to evaluate dental and skeletal changes after intraoral molar distalization. The maxillary molars were distalized with a sectional jig assembly. Sentalloy open coil springs were used to exert 150 gm of force for a period of 12 weeks. A modified Nance appliance was the main source of anchorage. The pre- and postdistalization records included dental study casts, clinical photographs, and cephalograms. A total of 665 readings recorded from lateral cephalograms and dental casts were subjected to statistical analysis. The mean distal movement of the first molar was 2.78 mm, which was highly significant (o < 0.001). It moved distally at the rate of 0.86 mm/month. There was clinically some distal tipping (3.50 degrees) and distopalatal rotation (2.40 degrees). These changes were statistically significant (p < 0.001). The second molars accompanied the first molars and moved distally by nearly the same amount. There was 1.00 mm increase in the overjet and 2.60 degrees mesial tip of second premolar. The changes in the facial skeleton and dentition bases were minimal and statistically not significant. However, there was clockwise rotation of the mandible of 1.30 degrees that was statistically significant. This was the result of molar extrusion (1.60 mm).

Psychological impact of third molar surgery: a 1-month prospective study

NARCIS (Netherlands)

de Jongh, Ad; van Wijk, Arjen J.; Lindeboom, Jerome A.

2011-01-01

To prospectively examine the psychological impact of surgical third molar removal, and to identify possible psychological risk factors for the development of dental anxiety and symptoms of psychological trauma. Patients (N = 71) scheduled for surgical mandibular third molar removal were assessed

Study of pulp chamber morphology of primary mandibular molars using spiral computed tomography.

Science.gov (United States)

Selvakumar, Haridoss; Kavitha, Swaminathan; Vijayakumar, Rajendran; Eapen, Thomas; Bharathan, Rajendran

2014-11-01

The purpose of this study was to evaluate the pulp chamber morphology in primary mandibular molars using spiral computed tomography (SCT). Sixty extracted primary mandibular molars were scanned using SCT for the (i) distance between the central fissure to furcation, (ii) distance between the central fissure to the floor of the pulp chamber, (iii) height of the pulp chamber (roof-floor), (iv) distance between the floor of the pulp chamber to the furcation. The mean and standard deviation was analyzed using statistical package for the social sciences (SPSS) program. The results of this study show that the average mean distance from the central fissure to the floor of the pulp chamber is 5.07 mm in first mandibular primary molar and 5.54 mm in second mandibular primary molar. It can be concluded that the greatest depth to which a bur can go during access opening without perforating the furcation in first primary mandibular molar is 5.07 mm and 5.54 mm in second primary mandibular molar.

Temporal abscess after third molar extraction in the mandible.

Science.gov (United States)

de Oliveira Neto, Patrício José; de Souza Maliska, Maximiana Cristina; Sawazaki, Renato; Asprino, Luciana; de Moraes, Márcio; Moreira, Roger William Fernandes

2012-03-01

Dental infections resulting before or after third molar removal are complications in which the maxillofacial surgeon may have to initiate an earlier management. The severe dental infections resulting before or after this procedure is one of the few life-threatening complications in which the maxillofacial surgeon may have to initiate an earlier management. Infections involving the temporal space are rare and infrequently reported. Infections in this space have also been observed secondary to maxillary sinusitis, maxillary sinus fracture, temporomandibular arthroscopy, and drug injection, although more commonly associated to third molar infections. A 22-year-old man had undergone extraction of tooth 38 secondary to pericoronaritis by a general dentist. Physical examination of his face demonstrated severe trismus, pain, and swelling in temporal region. A CT scan showed an inflammatory area into the temporal space. He was started on IV cephalosporin, but the clinical course of the patient was not satisfactory. Incision and drainage were performed from an extraoral and intraoral approach. After discharged, the antibiotic was switched to clindamycin IO 600 mg. The retromaxillary and temporal infections are quite common after maxillary molar extractions but not after mandibular third molar, the spread mechanism of ascension must be involved with the virulence of microorganisms, but more studies are necessary to clarify this occurrence.

X-RAY MEASUREMENTS OF IMPACTED MANDIBULAR THIRD MOLARS

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Petya G. Kanazirska

2017-03-01

Full Text Available The X-ray diagnostics is essential in case of retention of teeth. An important condition for proper treatment plan for impacted third molars of the mandible is the determination of the type of retention in the jaw in accordance with their medio-distal inclination and the space available for eruption (retromolar space. Purpose: The purpose of this article is to present an objective method for determination of the medio-distal inclination and the space for eruption of the third molars of the mandible. Materials and methods: The studied patients with impacted third molars of the mandible are 127, aged 17 through 60. They were examined with Cone-beam Computed Tomography (CBCT. On the orthopantomography, obtained after the scanning as a reconstructed image, we defined the medio-distal inclination and space for eruption of the third molars of the mandible. For this purpose, we summarized several methods. Results: The most common inclination of the third molars of the mandible with retained eruption is the medial one at 120 teeth (61.5% ± 3.5. Second in frequency is the vertical one-34 teeth (17.4% ± 2.7, followed by the distal inclination– 21 teeth (10.8% ± 2.2. With the lowest frequency are the teeth which are positioned horizontally –20 teeth (10.3% ± 2.2. Shortage of retromolar space is established for173 teeth (88.7% ± 2.3. In 22 teeth (11.3% ± 2.3 there is enough space in the jaw for eruption. Conclusion: An objective method for determination of the medio-distal inclination of the teeth and the space available for eruption is introduced for the first time in Bulgaria. By determining the inclination of impacted wisdom teeth under this methodology one can avoid the subjective factor–the seventh tooth. It is not a reference plane, because it can also be tilted or missing. With the help of the developed method the retromolar point can be determined more objectively.

Using cone beam computed thomography in planning the extraction of impacted third molars

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Vlahović Zoran

2016-01-01

Full Text Available The panoramic radiography is the most used diagnostic imaging method in planning impacted lower third molar extractions. However, often panoramic radiography does not provide enough information in treatment planning for performing safely surgical extraction of impacted third molars. CBCT (Cone beam computed tomography provides more precise information in diagnostic analysis especially for planning surgical procedures where complications can be expected due to close relationship between mandibular canal and lower impacted third molars. The aim of this study is comparative analysis of panoramic radiography and CBCT in evaluating the topographic relationship between mandibular canal and impacted third molars. The study included 50 patients with close relationship between mandibular canal and impacted third molars detected using panoramic radiography. After panoramic radiography analysis CBCT was performed in order to diagnose, plan and prevent complications during the surgical tooth extraction. CBCT examination considered comparative analysis with panoramic radiography, marking, volume rendering and assessment of mandibular canal in buccolingual direction. Out of total patients where suprimposition of mandibular canal and impacted third molar on panoramic radiography was detected, in 32 patients mandibular chanal was localised on lingual side. Mandibular canal was positioned at bucal side in 18 of 50 patients. Results of this research indicate that panoramic radiography can be useful in everyday practice for diagnosis, planning and preparing lower third molar extractions, but in cases where close relationship between mandibular canal and lower third molars is detected CBCT is recommended as more precise radiographic imaging method in order to prevent complications.

Association of infantile bruxism and the terminal relationships of the primary second molars.

Science.gov (United States)

Junqueira, Tatiana Helena; Nahás-Scocate, Ana Carla Raphaelli; Valle-Corotti, Karyna Martins do; Conti, Ana Claudia de Castro Ferreira; Trevisan, Shirley

2013-01-01

The aim of this study was to analyze the association between infantile bruxism and the terminal relationships of the primary second molars. A total of 937 pre-school children (both genders), aged from 2 to 6 years, from municipal schools in São Paulo were evaluated. In this study, a questionnaire considering the bruxism habit and the presence of headaches and/or restless sleep was answered by the parents/guardians. A clinical exam of occlusion in the anteroposterior direction (vertical plane - VP, mesial step - MS and distal step - DS) was performed by the examiners in the school environment. Student's t test, Fisher's test and a logistic regression test were applied for the statistical analysis at a significance level of 5%. The prevalence of the bruxism habit was 29.3% among the total sample. Because there was no significant difference between the sides evaluated, the left side was taken as the standard. Among those children with bruxism, 25.7% presented a mesial step terminal relationship at the primary second molars, 29.1% had DS, and 30.2% had VP. Regarding the association of the parafunctional habit with the type of terminal relationship, no significant results were found. Children who slept restlessly or suffered from headaches were verified to show a higher chance of expressing the habit (OR = 2.4 and 1.6, respectively). The prevalence of bruxism in the studied sample was 29.3%, and its association with the primary second molars' terminal relationship was not statistically significant.

Subcutaneous emphysema during third molar surgery: a case report

OpenAIRE

Romeo, Umberto; Galanakis, Alexandros; Lerario, Francesco; Daniele, Gabriele Maria; Tenore, Gianluca; Palaia, Gaspare

2011-01-01

Extraction of third molars is the most common surgical procedure performed in oral surgery on a daily basis and, despite surgical skills and expertise, complications may occur. Complications observed during or after third molar removal may include pain, swelling, bleeding, infection, sinus perforation and nerve damage. Fortunately, with a proper management and a good surgical technique, the incidence of such events is low. Subcutaneous emphysema associated with dental extraction occurs when t...

Molar incisor hypomineralization: current research evidences

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Manikandan Ekambaram

2016-06-01

Full Text Available Molar-Incisor Hypomineralization (MIH is a condition of systemic origin that involves one to four first permanent molar teeth and often associated with affected incisors. Although several associations to prenatal/perinatal childhood medical conditions have been reported, the etiology of MIH still remains unclear. The degree of enamel hypomineralization in the affected teeth can vary and the clinical problems associated with the teeth include increased susceptibility to caries, rapid wear, and post-eruptive enamel breakdown. Affected teeth are extremely challenging to treat as the enamel is porous, sensitive and treating clinicians might encounter great difficulty in achieving profound anaesthesia. The first part of thispresentation will give an update on prevalence, potential etiological factors, and management strategies of this condition. The second part of the presentation will cover a systematic review results on bonding strategies to hypomineralized enamel.

Molar mass of poly(ethylene terephthalate) (PET) during ultimate uniaxial drawing

NARCIS (Netherlands)

Göschel, U.; Cools, P.J.C.H.

2000-01-01

The changes of the average molar mass Mw, Mn, Mz, and molar mass distributions during multistep uniaxial drawing of poly(ethylene terephthalate) (PET) to achieve ultimate mechanical properties have been studied in detail by means of size exclusion chromatography (SEC) with triple detection:

Molar-Mass of Poly(Ethylene-Terephthalate) (PET) During Ultimate Uniaxial Drawing

NARCIS (Netherlands)

Göschel, A.G.P.U.; Cools, P.J.C.H.

2000-01-01

The changes of the average molar mass Mw, Mn, Mz, and molar mass distributions during multistep uniaxial drawing of poly(ethylene terephthalate) (PET) to achieve ultimate mechanical properties have been studied in detail by means of size exclusion chromatography (SEC) with triple detection:

Micro-CT analyses of apical enlargement and molar root canal complexity

DEFF Research Database (Denmark)

Markvart, Merete; Darvann, Tron Andre; Larsen, Per

2012-01-01

AIM: To compare the effectiveness of two rotary hybrid instrumentation techniques with focus on apical enlargement in molar teeth and to quantify and visualize spatial details of instrumentation efficacy in root canals of different complexity. METHODOLOGY: Maxillary and mandibular molar teeth wer...

Optimum injection dose rate of hydrogen sulfide scavenger for treatment of petroleum crude oil

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T.M. Elshiekh

2016-03-01

Full Text Available Hydrogen sulfide H2S scavengers are chemicals that favorably react with hydrogen sulfide gas to eliminate it and produce environmental friendly products. These products depend on the type and composition of the scavenger and the conditions at which the reaction takes place. The scavenger should be widely available and economical for industry acceptance by having a low unit cost. The optimum values of H2S scavenger injection dose rate of scavenging hydrogen sulfide from the multiphase fluid produced at different wells conditions in one of the Petroleum Companies in Egypt were studied. The optimum values of H2S scavenger injection dose rate depend on pipe diameter, pipe length, gas molar mass velocity, inlet H2S concentration and pressure. The optimization results are obtained for different values of these parameters using the software program Lingo. In general, the optimum values of H2S scavenger injection dose rate of the scavenging of hydrogen sulfide are increased by increasing of the pipe diameter and increasing the inlet H2S concentration, and decreased by increasing the pipe length, gas molar mass velocity and pressure.

Changes in higher mental functions in persons with late sequels of exposure to small ionizing radiation doses

International Nuclear Information System (INIS)

Turuspekova, S.

2002-01-01

This is a report on the results of studies on the state of higher mental function in individuals with a previous history of exposure to small doses ionizing radiations. The disorders observed are assigned under several groups as follows: dyspraxia, gnostic, visual-spatial agnosia, mnestic, mental processes impairment, neurodynamic. Mnestic and acoustic-gnostical disturbances, and those of the mental processes are rather markedly expressed. Mnestic derangements play a major role in the general pattern of cognitive disorders, being characterized by both modal-specific, and modal-nonspecific features. The topical principle of the classification proposed enables to distinguish the syndrome of middle nonspecific brain structures involvement and the cortical syndromes among the higher mental function disorders, invariably encountered in combination and not isolated. The aforementioned points to the diffuse nature of the neuropsychological disorders, with involvement in the process of both nonspecific and specific structures, characterized by predomination of the frontal and temporal brain cortex sections. Impairment of the higher mental functions in young persons of active age with a past history of exposure to small doses ionizing radiations, necessitate to work out effective measures precluding occurrence and intensification of the cognitive defect. (author)

Dispositivo de seguridad para controlar mejor el tercer molar impactado durante exodoncia: Una nueva técnica Security device for a better control of impacted third molars during exodontia: A new technique

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F. Hernández Altemir

2005-04-01

Full Text Available El desplazamiento accidental del tercer molar impactado es una complicación que ocurre de vez en cuando durante la exodoncia. La recuperación de estos dientes accidentalmente desplazados puede ser compleja debido a la mala visibilidad y el espacio limitado. Describimos una técnica fácil basada en un sistema de anclaje para controlar mejor los terceros molares impactados durante la exodoncia.Accidental displacement of impacted third molars is a complication that occasionally occurs during exodontia. The retrieval of these accidentally displaced third molars may be complex due to poor visibility and limited space. We describe an easy technique for a better control of impacted third molars during exodontia based on an anchoring system.

Four osteotomy methods with piezosurgery to remove complicated mandibular third molars: a retrospective study.

Science.gov (United States)

Ge, Jing; Yang, Chi; Zheng, Jia-Wei; He, Dong-Mei; Zheng, Ling-Yan; Hu, Ying-Kai

2014-11-01

Piezosurgery has been used widely in oral and maxillofacial surgery, but there has been no report systematically describing an osteotomy method with piezosurgery for complicated mandibular third molar removal. The aim of this study was to introduce 4 osteotomy methods using piezosurgery and evaluate their effects. A retrospective study was conducted of patients with a complicated impacted mandibular third molar requiring extraction. The predictor variable was the extraction technique. Four osteotomy methods using piezosurgery were tested according to different impaction types: method 1 involved complete bone removal; method 2 involved segmental bone removal; method 3 involved bone removal combined with tooth splitting; and method 4 involved block bone removal. Outcome variables were success rate, operative time, major complications (including nerve injury, mandible fracture, severe hematoma, or severe edema), and serious pyogenic infection. Data were analyzed using descriptive statistics. The study was composed of 55 patients with 74 complicated impacted mandibular third molars. All impacted mandibular third molars were removed successfully. The average surgical time was 15 minutes (range, 8 to 26 minutes). Thirty-eight molars (51.4%) were extracted by method 1, 18 molars (24.3%) by method 2, 12 molars (16.2%) by method 3, and 6 molars (8.1%) by method 4. Two cases (2.7%) developed postoperative infections and recovered within 1 week using drainage and antibiotic administration. The 4 osteotomy methods with piezosurgery provide effective ways of removing complicated impacted mandibular third molars. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Molar incisor hypomineralisation (MIH): correlation with dental caries and dental fear.

Science.gov (United States)

Kosma, I; Kevrekidou, A; Boka, V; Arapostathis, K; Kotsanos, N

2016-04-01

This cross-sectional study was to investigate correlations between molar incisor hypomineralisation (MIH), dental caries and child dental fear. The subjects in the study were representative samples of 8 and 14 year old children from three Greek cities (total N = 2335). Dental examinations were performed by one calibrated examiner in classrooms, after the children had brushed their teeth, using an intraoral mirror and artificial room light supplemented by a penlight. All the children completed the children's fear survey schedule-dental subscale (CFSS-DS) questionnaire. MIH scores were recorded using EAPD criteria and dental caries experience by DMFS/dmfs index. Data were analysed with the Chi-squared (χ (2)), Mann-Whitney and Spearman's rank correlation coefficient tests. The mean DMFS in children with MIH (8-year olds: 1.60 ± 2.01, 14-year olds: 4.60 ± 4.41) was statistically significantly higher than children without MIH (8-year olds: 1.01 ± 1.78, 14-year olds: 3.46 ± 4.28) (p MIH had statistically significantly higher mean DMFS scores than children with mild or no MIH (p MIH status (p = 0.332). Caries experience was associated with the MIH status of the first permanent molars in both age groups (p MIH (26.5 ± 9.6) (p = 0.339), regardless of MIH severity. A positive association between MIH and dental caries was confirmed and a lack of association found between MIH and dental fear in Greek children.

Comparative analysis of the first permanent molars caries prevalence in younger and older school children

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Stojković Branislava B.

2012-01-01

Full Text Available Introduction. The data on the health-condition of the first permanent molars among children in our region is scarce. Therefore, the need for more thorough analysis of the state of health of these teeth in the children from our region imposes itself, along with the need to determine the most critical period in which a significant increase in caries prevalence of these teeth takes place. Aim. The aim of the research was to perform a comparative analysis of the prevalence, average rate and structure of decay, missed and filled first permanent molars in the children of the younger school age in relation to those of the older school age. Material and methods. The research included 1.119 examinees, aged from 7 to 14 years. Examinees were divided into two groups according to their age: examinees of the younger school age and older school age. Dental check-up of the students was performed by means of a dental probe and mirror and the health condition of the examined teeth was registered by means of Klein-Palmer's DMF system. Results. The research determined high values of the examined parameters of the first permanent molars caries prevalence which increases with the age of the examinees. In the examinees of the age of 8, 9, and 10, statistically more significant values of the examined teeth caries prevalence parameters were registered, in relation to the examinees of seven years of age. In the examinees of the older school age, statistically significantly higher values were registered only for TCI and ACI and only in the examinees aged 14 in relation to the examinees aged 11. With the age, the percent of decay is decreases, while the percent of filled and extracted first permanent molars increases. Conclusion. Results show that the period between 7 and 10 years of age is the most critical and the most important period for the implementation of preventive-prophylactic measures aimed to preserve the health of the first permanent molars.

Restorasi Resin Komposit Menggunakan Pasak Tapered Self Threading Pada Molar Ketiga Kiri Mandibula

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Ellen Krisanti

2013-06-01

Composite Resin Restoration Using Tapered Self Threading Poston Left Mandibular Third Molar. Root canal morphology of mandibular third molar has more complex variation than the other molars. In third molar, the extraction teeth are often executed; however, the third molar can be maintained in other conditions. One visit root canal treatment is a therapy option for this case. The purpose of this case report is to show the success of one visit root canal treatment in third molar with pulp necrosis by restoring the composite resin through tapered self-treading post. A 20 year-old female patient who came to the Prof Soedomo RSGM, FKG UGM complained about the pain when chewing food on her third molar and positive in percussion. The radiographs showed that there was an incomplete restoration. There was a gap between cavities with restoration. The treatment plan for this case was one visit root canal treatment and composite resin with tapered self-threading post as final restoration. From the case, it can concluded that one visit root canal treatment results in a smaller chance for microorganism recontamination than the multi-visit in order to ensure the success of the treatment. Direct composite resin restoration with tapered self-threading dowel is an alternative restoration after endodontic treatment because it works out faster and more retentive.

Immediate Placement of Ultrawide-Diameter Implants in Molar Sockets: Description of a Recommended Technique

NARCIS (Netherlands)

Hattingh, A.C.; Bruyn, H. de; Ackermann, A.; Vandeweghe, S.

2018-01-01

Immediate implant placement is performed less frequently in molar extraction sockets than in single root sockets. This is mainly due to the tripodal anatomical configuration of molar roots, which is perceived as complex and therefore unsuitable. The mechanical burden of molar sites, combined with

Is It All about the Higher Dose? Why Psychoanalytic Therapy Is an Effective Treatment for Major Depression.

Science.gov (United States)

Zimmermann, Johannes; Löffler-Stastka, Henriette; Huber, Dorothea; Klug, Günther; Alhabbo, Sarah; Bock, Astrid; Benecke, Cord

2015-01-01

Empirical evidence for the effectiveness of long-term psychodynamic psychotherapy (LTPP) in patients with mood disorders is growing. However, it is unclear whether the effectiveness of LTPP is due to distinctive features of psychodynamic/psychoanalytic techniques or to a higher number of sessions. We tested these rival hypotheses in a quasi-experimental study comparing psychoanalytic therapy (i.e., high-dose LTPP) with psychodynamic therapy (i.e., low-dose LTPP) and cognitive-behavioural therapy (CBT) for depression. Analyses were based on a subsample of 77 subjects, with 27 receiving psychoanalytic therapy, 26 receiving psychodynamic therapy and 24 receiving CBT. Depressive symptoms, interpersonal problems and introject affiliation were assessed prior to treatment, after treatment and at the 1-, 2- and 3-year follow-ups. Psychoanalytic techniques were assessed from three audiotaped middle sessions per treatment using the Psychotherapy Process Q-Set. Subjects receiving psychoanalytic therapy reported having fewer interpersonal problems, treated themselves in a more affiliative way directly after treatment and tended to improve in depressive symptoms and interpersonal problems during follow-up as compared with patients receiving psychodynamic therapy and/or CBT. Multilevel mediation analyses suggested that post-treatment differences in interpersonal problems and introject affiliation were mediated by the higher number of sessions, and follow-up differences in depressive symptoms were mediated by the more pronounced application of psychoanalytic techniques. We also found some evidence for indirect treatment effects via psychoanalytic techniques on changes in introject affiliation during follow-up. These results provide support for the prediction that both a high dose and the application of psychoanalytic techniques facilitate therapeutic change in patients with major depression. Psychoanalytic therapy is an effective treatment for major depression, especially in the

Ectopic Molar Pregnancy: Diagnostic Efficacy of Magnetic Resonance Imaging and Review of the Literature.

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Yamada, Yasushi; Ohira, Satoshi; Yamazaki, Teruyuki; Shiozawa, Tanri

2016-01-01

Ectopic molar pregnancy is extremely rare, and preoperative diagnosis is difficult. Our literature search found only one report of molar pregnancy diagnosed preoperatively. Moreover, there is no English literature depicting magnetic resonance image (MRI) findings of ectopic molar pregnancy. We report a case of ectopic molar pregnancy preoperatively diagnosed using MRI. A literature review of 31 cases of ectopic molar pregnancy demonstrated that lesions have been found in the fallopian tube (19 cases, 61%), ovary (5 cases, 16%), cornu (3 cases, 10%), peritoneum (2 cases, 6%), uterine cervix (1 case, 3%), and cesarean scar (1 case, 3%). Abdominal pain and abnormal vaginal bleeding were reported in 70% and 61% of the patients, respectively. Twenty-one cases (67%) presented with rupture and hemoperitoneum. All patients underwent surgical resection or dilatation and curettage. Methotrexate therapy was performed in one case because residual trophoblastic tissue was suspected. A second operation was performed in one case of ovarian molar pregnancy because serum hCG levels increased again after primary focal ovarian resection. No patients developed metastatic disease or relapsed. These findings suggest the prognosis of ectopic molar pregnancy to be favorable.

Ectopic Molar Pregnancy: Diagnostic Efficacy of Magnetic Resonance Imaging and Review of the Literature

Directory of Open Access Journals (Sweden)

Yasushi Yamada

2016-01-01

Full Text Available Ectopic molar pregnancy is extremely rare, and preoperative diagnosis is difficult. Our literature search found only one report of molar pregnancy diagnosed preoperatively. Moreover, there is no English literature depicting magnetic resonance image (MRI findings of ectopic molar pregnancy. We report a case of ectopic molar pregnancy preoperatively diagnosed using MRI. A literature review of 31 cases of ectopic molar pregnancy demonstrated that lesions have been found in the fallopian tube (19 cases, 61%, ovary (5 cases, 16%, cornu (3 cases, 10%, peritoneum (2 cases, 6%, uterine cervix (1 case, 3%, and cesarean scar (1 case, 3%. Abdominal pain and abnormal vaginal bleeding were reported in 70% and 61% of the patients, respectively. Twenty-one cases (67% presented with rupture and hemoperitoneum. All patients underwent surgical resection or dilatation and curettage. Methotrexate therapy was performed in one case because residual trophoblastic tissue was suspected. A second operation was performed in one case of ovarian molar pregnancy because serum hCG levels increased again after primary focal ovarian resection. No patients developed metastatic disease or relapsed. These findings suggest the prognosis of ectopic molar pregnancy to be favorable.

Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: variation within species and relevance to risk communication.

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Burger, Joanna; Gochfeld, Michael

2013-07-01

There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 are at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others. Copyright © 2013 Elsevier Ltd. All rights reserved.

Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: Variation within species and relevance to risk communication

Science.gov (United States)

Burger, Joanna; Gochfeld, Michael

2015-01-01

There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 may be at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others. PMID:23541437

Relationship between the partial molar and molar quantity of a thermodynamic state function in a multicomponent mixture – revisited

International Nuclear Information System (INIS)

Näfe, H.

2013-01-01

As far as a multicomponent mixture is concerned, different versions exist in the literature for the relationship between the partial molar and molar quantity of a thermodynamic state function with the most prominent example of the two quantities being the activity coefficient of an arbitrary component and the excess Gibbs free energy of a mixture comprising this component. Since the relationships published so far have to a large degree been derived independently of each other and result from apparently conflicting approaches, they are still considered as separate subjects in the literature. It is demonstrated that despite this curious situation all relationships are equivalent to each other from a mathematical point of view

Monte Carlo method for dose calculation due to oral X-rays

International Nuclear Information System (INIS)

Loureiro, Eduardo Cesar de Miranda

1998-06-01

The increasing utilization of oral X-rays, especially in youngsters and children, calls for the assessment of equivalent doses in their organs and tissues. With this purpose, a Monte Carlo code was adapted to simulate an X-ray source irradiating phantoms of the MIRD-5 type with different ages (10, 15 and 40 years old) to calculate the conversion coefficients which transform the exposure at skin to equivalent doses at several organs and tissues of interest. In order to check the computer program, simulations were performed for adult patients using the original code (ADAM.FOR developed at the GSF-Germany) and the adapted program (MCDRO.PAS). Good agreement between results obtained with both codes was observed. Irradiations of the incisive, canine and molar teeth were simulated. The conversion factors were calculated for the following organs and tissues: thyroid, active bone narrow (head and whole body), bone (facial skeleton, cranium and whole body), skin (head and whole body) and crystalline. Based on the obtained results, it follows that the younger the patient and the larger the field area, the higher the dose in assessed organs and tissues. The variation of the source-skin distance does not change the conversion coefficients. On the other hand, the increase in the voltage applied to the X-ray tube causes an increase in the calculated conversion coefficients. (author)

Excess molar volumes of binary mixtures (an ionic liquid + water): A review

International Nuclear Information System (INIS)

Bahadur, Indra; Letcher, Trevor M.; Singh, Sangeeta; Redhi, Gan G.; Venkatesu, Pannuru; Ramjugernath, Deresh

2015-01-01

Highlights: • Review of excess molar volumes for mixtures of (ionic liquids (ILs) + H 2 O). • 6 cation groups reviewed including imidazolium and pyrrolidinium groups. • 13 anions reviewed including tetraborate, triflate, and hydrogensulphate. • Effects of anion, cation, and temperature investigated. - Abstract: This review covers recent developments in the area of excess molar volumes for mixtures of {ILs (1) + H 2 O (2)} where ILs refers to ionic liquids involving cations: imidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium and ammonium groups; and anions: tetraborate, triflate, hydrogensulphate, methylsulphate, ethylsulphate, thiocyanate, dicyanamide, octanate, acetate, nitrate, chloride, bromide, and iodine. The excess molar volumes of aqueous ILs were found to cover a wide range of values for the different ILs (ranging from −1.7 cm 3 · mol −1 to 1.2 cm 3 · mol −1 ). The excess molar volumes increased with increasing temperature for all systems studied in this review. The magnitude and in some cases the sign of the excess molar volumes for all the aqueous ILs mixtures, apart from the ammonium ILs, were very dependent on temperature. This was particularly important in the dilute IL concentration region. It was found that the sign and magnitude of the excess molar volumes of aqueous ILs (for ILs with hydrophobic cations), was more dependent on the nature of the anion than on the cation

Impaction of lower third molars and their association with age: radiological perspectives.

Science.gov (United States)

Ryalat, Soukaina; AlRyalat, Saif Aldeen; Kassob, Zaid; Hassona, Yazan; Al-Shayyab, Mohammad H; Sawair, Faleh

2018-04-04

Third molars are the most commonly impacted teeth, and their extraction is the most commonly performed procedure in oral and maxillofacial surgery. The aim of the present study is to describe the pattern of mandibular third molar impaction and to define the most appropriate age for prophylactic extraction of mandibular third molar teeth. A total of 1198 orthopantomographs (OPGs) with 1810 impacted lower third molars were reviewed by two authors. The pattern of eruption in relation to patient's age was examined using standard radiographic points and angles. Statistical analysis was performed using SPSS for Windows release 16.0 (SPSS Inc., Chicago, IL, USA). In patients older than 20 years, vertical pattern of impaction was the most common (21.4%); while in young patients; horizontal impaction was more common (21.3%). Furthermore, there was a constant pattern of increase in Pell-Gregory ramus class 1 with increasing age, as the prevalence of class 1 was 0% at age 18 years compared to 54.9% at the age of 26 years. Frequency of vertical impaction of lower third molars was seen more at an older age (> 20 years) in this study, with an increase in the retromolar space. Late extraction of mandibular third molar teeth (i.e. after the age of 20) is therefore recommended when prophylactic extraction is considered.

Assessment of dose in thyroid and salivary glands in dental radiology using thermoluminescent dosimetry

International Nuclear Information System (INIS)

Mantuano, Natalia de O.; Silva, Ademir X. da; Correa, Samanda C.A.

2011-01-01

Radiobiological and epidemiological studies have provided evidence of risk of salivary and thyroid glands tumors incidence associated with oral radiology. Based on these studies, the tissue weighting factors were reviewed by the International Commission on Radiological Protection (ICRP) in 2007. The main objective of the present work is to estimate the absorbed dose on thyroid and salivary glands (parotid, submandibular and sublingual), during a complete periapical examination. The complete periapical examination was simulated using a Spectro 70X Seletronic X-ray dental equipment on an Alderson Rando phantom with Harshaw LiF:Mg,Ti thermoluminescent dosemeters (TLD100). A PTW DIADOS dosimetric system was used for calibration. The TLD100 were inserted into the phantom slices corresponding to the organs of interest. During a complete periapical examination, the highest evaluated mean absorbed dose was 4.9 mGy in the right submandibular gland and the lowest one of 1.5 mGy in the left thyroid lobe. Entrance surface doses ranged from 2.1 to 2.6 mGy, measured, respectively, for the techniques of upper left molar and lower right molar. When compared with the diagnostic reference levels (DRL), the entrance surface doses values were lower than the DRLs recommended in Brazilian current legislation. However, the dosimetric results show the need of optimization for complete periapical examination to minimize patient exposure. Measurements were performed without the use of thyroid protectors. The use of this device is certainly an easy and simple method of dose reduction. (author)

Assessment of dose in thyroid and salivary glands in dental radiology using thermoluminescent dosimetry

Energy Technology Data Exchange (ETDEWEB)

Mantuano, Natalia de O.; Silva, Ademir X. da [Instituto Alberto Luiz Coimbra de Pos-Graduacao e Pesquisa em Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear; Canevaro, Luca V.; Mauricio, Claudia Lucia P. [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ) Rio de Janeiro, RJ (Brazil); Correa, Samanda C.A., E-mail: scorrea@cnen.gov.b [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

2011-07-01

Radiobiological and epidemiological studies have provided evidence of risk of salivary and thyroid glands tumors incidence associated with oral radiology. Based on these studies, the tissue weighting factors were reviewed by the International Commission on Radiological Protection (ICRP) in 2007. The main objective of the present work is to estimate the absorbed dose on thyroid and salivary glands (parotid, submandibular and sublingual), during a complete periapical examination. The complete periapical examination was simulated using a Spectro 70X Seletronic X-ray dental equipment on an Alderson Rando phantom with Harshaw LiF:Mg,Ti thermoluminescent dosemeters (TLD100). A PTW DIADOS dosimetric system was used for calibration. The TLD100 were inserted into the phantom slices corresponding to the organs of interest. During a complete periapical examination, the highest evaluated mean absorbed dose was 4.9 mGy in the right submandibular gland and the lowest one of 1.5 mGy in the left thyroid lobe. Entrance surface doses ranged from 2.1 to 2.6 mGy, measured, respectively, for the techniques of upper left molar and lower right molar. When compared with the diagnostic reference levels (DRL), the entrance surface doses values were lower than the DRLs recommended in Brazilian current legislation. However, the dosimetric results show the need of optimization for complete periapical examination to minimize patient exposure. Measurements were performed without the use of thyroid protectors. The use of this device is certainly an easy and simple method of dose reduction. (author)

Periodontal considerations in the use of bonds or bands on molars in adolescents and adults.

Science.gov (United States)

Boyd, R L; Baumrind, S

1992-01-01

This longitudinal study compared the periodontal status of bonded and banded molars in 20 adult and 40 adolescent patients before, during and after treatment with fixed orthodontic appliances. Plaque accumulation (measured by the Plaque Index), gingival inflammation (measured by the Gingival Index and the bleeding tendency), and pocket depth were assessed by one examiner at sites along the mesio-buccal line angle of the maxillary right first molar and the mandibular left first molar. Assessments were made immediately prior to the placement of fixed appliances (pretreatment), at 1, 3, 6, 9, 12 and 18 months after appliances were placed; and 3 months after appliances were removed (posttreatment). Loss of attachment between the pretreatment and posttreatment visits also was determined. At pretreatment, no significant differences were found in gingival inflammation between maxillary and mandibular banded and bonded molars. During treatment, both maxillary and mandibular banded molars showed significantly (p less than 0.05) greater gingival inflammation and plaque accumulation than did bonded molars. Three months after appliance removal, the maxillary molars that had been banded continued to show significantly more gingival inflammation and loss of attachment than did the maxillary molars that had been bonded. When all banded and bonded teeth were grouped by patient age, mean values for plaque accumulation and gingival inflammation in the maxillary molar regions were significantly greater for adolescents than for adults.

Polarization and molar volumes of ortho- and para-deuterium solutions

International Nuclear Information System (INIS)

Milenko, Yu.Ya.; Sibileva, R.M.

1976-01-01

The dielectric constant of liquid solutions of ortho-and para-deuterium is measured over the range of 2.2-91% p-D 2 from 18.7 to 20.4deg K. Data on polarization and molar volumes are obtained for the whole (0-100%) concentration range. Corrected summary to paper [2] is also listed: dielectric constant of ortho- and para-hydrogen liquid solution is measured within a concentration range of 0-97% of o-molecules at 14-20.4deg K. It is established that dependence of the Clausius-Mossotti function for o-p-hydrogen solutions of o-p-composition is linear. Molar volumes of the o-p-mixtures are calculated. The excessive molar volumes are found, positive deviation from additivity, 0.15% is established

Origin of choriocarcinoma in previous molar pregnancy proved by DNA analysis

International Nuclear Information System (INIS)

Vojtassak, J.; Repiska, V.; Konecna, B.; Zajac, V.; Korbel, M.; Danihel, L.

1996-01-01

A 17-year old woman had in a short time period (seven months) a very exciting reproduction history. Molar pregnancy in December 1993, choriocarcinoma in January 1994 and induced abortion in June 1994. DNA analysis proved the origin of the choriocarcinoma in the previous molar pregnancy. (author)

Assessment of age of majority by measurement of open apices of the third molars using Cameriere's third molar maturity index.

Science.gov (United States)

Sharma, Preeti; Wadhwan, Vijay; Ravi Prakash, S M; Aggarwal, Pooja; Sharma, Neeraj

2017-01-01

Evaluation of biological age of a living subject around the legal cutoff age for adulthood has become a grave concern for forensic experts in India, mainly due to the consequences of criminal obligations in judicial proceedings. Thus, this study was planned to examine the open apices of third molars in discriminating between individuals who are aged 18 years or older and who are not 18 years or older and to assign a cutoff for estimation of the age of 18 years. Orthopantomographs of 1062 individuals (14 and 23 years) were assessed, to verify Cameriere's third molar maturity index (I 3M ). The apical ends of the roots of the left mandibular third molar were analyzed. If the apical ends of the roots are completely closed, then I 3M is zero; otherwise, it is calculated as the sum of the distances between the inner sides of the two open apices divided by the tooth length. The sensitivity of the test for 0.08 value was 74.7% for males and 66% for females. Specificity was 83.6% for males and 79.6% for females. The probability that an Indian individual with an I 3M age in Indian population.

Endodontic therapy for a fused mandibular molar.

Science.gov (United States)

Rotstein, I; Moshonov, J; Cohenca, N

1997-06-01

Variations in tooth morphology present a clinical challenge when endodontic treatment is required. A case of conservative endodontic therapy for a fused mandibular second and third molar is presented.

Fate of third molar in line of mandibular angle fracture - Retrospective study

Directory of Open Access Journals (Sweden)

Preetha Balaji

2015-01-01

Conclusion: The present study fails to identify any concrete factors that would predict the failure of the retained third molar that were involved in the line of mandibular fractures. The proof presented here, especially with low complication rates indicate that all impacted third molar along the line of fracture be removed and unless necessary, the partially erupted teeth would also be extracted. In such a situation, the rate of infection and survival of the third molar would have been entirely different.

Clinical and orthopantomographic evaluation of mandibular third molar

Directory of Open Access Journals (Sweden)

F K Saraswati

2010-01-01

Full Text Available Objective: To evaluate sensitivity of orthopentograph (OPG in assessing the number and morphology of roots of the mandibular third molar. Materials and Methods : The study population consisted of 100 ILTMs (impacted lower third molars ranging from 18 to 42 years with equal sex distribution. All the teeth were subsequently extracted , collected and compared with OPG features for position, numb,er, morphology, and relation to mandibular canal. Conclusion: In conclusion, a large sample study is suggested with techniques like Clark′s and right angle technique which determines the three-dimensional orientation of the impacted teeth.

Molar-incisor-hypomineralisation (MIH). Retrospective clinical study in Greek children. I. Prevalence and defect characteristics.

Science.gov (United States)

Lygidakis, N A; Dimou, G; Briseniou, E

2008-12-01

This was to evaluate the prevalence and the clinical characteristics of MIH in a group of Greek children. During the years 2003--2005, all MIH cases diagnosed according to the recently set criteria were selected from the new patients clinic of a Community Dental Centre for Children (Athens). Age, gender and teeth involved were recorded. The severity of MIH was determined collectively by dividing the affected teeth in two groups; a) mild defect (demarcated opacities) and b) moderate/severe defect (enamel breakdown and atypical restorations). Evaluation of the distribution of the affected teeth within MIH cases was performed in a separate group of 225 affected children aged 8-12 years with their entire 12 'index' teeth erupted. From the 3,518, 5.5 to 12 year old children that were examined, there were 360 (10.2%) children with MIH, 211 (58.6%) females and 149 (41.4%) males, with 1,926 affected teeth, 1,231 molars and 695 incisors. In the molars group, maxillary molars were more frequently affected (87.8/90.3%) than mandibular (81.7/82.2%). In the central incisor group, maxillary teeth were also more frequently affected (50/55%) than mandibular (24.4/25%), while laterals were the least affected. In all there were 37.9% molars with moderate/severe defects as compared with 4.9% incisors, the remaining 62.1% and 95.1% respectively being mild. The various associations between the affected teeth were evaluated in the sub-group of 225 MIH children with all 'index' teeth erupted (1,286 affected teeth, 776 molars and 510 incisors), with mean number of affected teeth per child being 5.7; separately for molars 3.4 and for incisors 2.2. In these cases 28.4% of the children had only molars affected and 71.6% had both molars and incisors. In descending order the associations of affected teeth more frequently found were: 4 molars/2 incisors (23.5%), 4 molars/4 incisors (16.8%), 4 molars alone (15.1%) and 2 molars alone (9.7%), the remaining being much less. As age increased the

Standard molar enthalpies of formation of three methyl-pyrazole derivatives

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Cabral, Joana I.T.A.

2012-01-01

Highlights: ► Combustion calorimetry was used to determine Δ f H m ∘ (cr) of methyl-pyrazole derivatives. ► Vapour pressures were determined by the Knudsen mass-loss effusion technique. ► Gas-phase Δ f H m ∘ of the studied compounds have been derived. - Abstract: The standard (p ° = 0.1 MPa) molar enthalpies of formation of the crystalline 3-methyl-1-pyrazolecarboxamide; 3-methyl-3-pyrazoline-5-one; and 4-methyl-2-pyrazoline-5-one were derived from the standard massic energies of combustion, in oxygen, to yield CO 2 (g), H 2 O (l) and N 2 (g), at T = 298.15 K, measured by static bomb combustion calorimetry. The standard molar enthalpies of sublimation were calculated from the variation of the vapour pressures of each compound with temperature, measured by the Knudsen effusion technique. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the pyrazole derivatives, in the gaseous phase, at T = 298.15 K. The derived standard molar enthalpies of formation, in gaseous state, are analyzed in terms of enthalpic increments and interpreted in terms of molecular structure.

Hypomineralized second primary molars: prevalence data in Dutch 5-year-olds

NARCIS (Netherlands)

Elfrink, M.E.C.; Schuller, A.A.; Weerheijm, K.L.; Veerkamp, J.S.J.

2008-01-01

The aim of this cross-sectional observational study was to report on the prevalence of hypomineralizations in second primary molars in 5-year-old Dutch children. In the study 386 (45% girls) 5-year-old Dutch children, all insured by a Health Insurance Fund, participated. Scoring criteria for molar

Comparison of the analgesic efficacy of preoperative/postoperative oral dexketoprofen trometamol in third molar surgery: A randomized clinical trial.

Science.gov (United States)

Esparza-Villalpando, Vicente; Chavarria-Bolaños, Daniel; Gordillo-Moscoso, Antonio; Masuoka-Ito, David; Martinez-Rider, Ricardo; Isiordia-Espinoza, Mario; Pozos-Guillen, Amaury

2016-09-01

The aim of this study was to compare the efficacy of preoperative and postoperative dexketoprofen trometamol for pain control after third molar surgery. Sixty subjects indicated for impacted mandibular third molar surgery were randomly assigned to two groups: preoperative (group 1, n = 30) and postoperative (group 2, n = 30) administration. Group 1 received 25 mg of dexketoprofen trometamol 30 min before surgery and 1 placebo capsule (same color and size with active drug) immediately after surgery. Group 2 received the placebo capsule 30 min before surgery and 25 mg of dexketoprofen trometamol immediately after surgery. Pain intensity was assessed using a numeric rating scale (NRS) during the first 8 h. The time of the need for a second dose of dexketoprofen trometamol, after the first administration, was recorded. The data were analyzed using mixed-model repeated-measures (MMRM), Wilcoxon rank-sum, and Kaplan-Meier analysis. After the 8 h period, no statistically significant difference was observed in the intensity of pain (MMRM, p = 0.41); and no significant difference in the time for a second dose (p = 0.956). In conclusion, preoperative administration of dexketoprofen trometamol is a reasonable clinical approach that is as effective as conventional postoperative pharmacological treatment, with the advantage of allowing early analgesia before pain develops. (ClinicalTrials.gov: NCT02380001). Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Three-dimensional primate molar enamel thickness.

Science.gov (United States)

Olejniczak, Anthony J; Tafforeau, Paul; Feeney, Robin N M; Martin, Lawrence B

2008-02-01

Molar enamel thickness has played an important role in the taxonomic, phylogenetic, and dietary assessments of fossil primate teeth for nearly 90 years. Despite the frequency with which enamel thickness is discussed in paleoanthropological discourse, methods used to attain information about enamel thickness are destructive and record information from only a single plane of section. Such semidestructive planar methods limit sample sizes and ignore dimensional data that may be culled from the entire length of a tooth. In light of recently developed techniques to investigate enamel thickness in 3D and the frequent use of enamel thickness in dietary and phylogenetic interpretations of living and fossil primates, the study presented here aims to produce and make available to other researchers a database of 3D enamel thickness measurements of primate molars (n=182 molars). The 3D enamel thickness measurements reported here generally agree with 2D studies. Hominoids show a broad range of relative enamel thicknesses, and cercopithecoids have relatively thicker enamel than ceboids, which in turn have relatively thicker enamel than strepsirrhine primates, on average. Past studies performed using 2D sections appear to have accurately diagnosed the 3D relative enamel thickness condition in great apes and humans: Gorilla has the relatively thinnest enamel, Pan has relatively thinner enamel than Pongo, and Homo has the relatively thickest enamel. Although the data set presented here has some taxonomic gaps, it may serve as a useful reference for researchers investigating enamel thickness in fossil taxa and studies of primate gnathic biology.

Pressure Dependence of Molar Volume near the Melting Point in Benzene

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The pressure dependence of the molar volume was at constant temperatures close to the melting point in benzene. The molar volume of benzene was calculated using experimental data for the thermal expansivity for constant temperatures of 25℃, 28.5℃, 40℃, and 51℃ at various pressures for both the solid and liquid phases. The predictions are in good agreement with the observed volumes in both the solid and liquid phases of benzene. The predicted values of the molar volume for a constant temperature of 28.5℃ in the liquid phase of benzene agree well with experimental data in the literature.

Standard molar enthalpies of formation of 2-furancarbonitrile, 2-acetylfuran, and 3-furaldehyde

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Amaral, Luisa M.P.F.

2009-01-01

The standard (p 0 = 0.1 MPa) molar energies of combustion of 2-furancarbonitrile, 2-acetylfuran, and 3-furaldehyde were measured by static bomb combustion calorimetry; the Calvet high-temperature microcalorimetry was used to measure the enthalpies of vaporization of these liquid compounds. The standard molar enthalpies of formation of the three compounds, in the gaseous phase, at T = 298.15 K, have been derived from the corresponding standard molar enthalpies of formation in the liquid phase and the standard molar enthalpies of phase transition, as (106.8 ± 1.1) kJ . mol -1 , -(207.4 ± 1.3) kJ . mol -1 , and -(151.9 ± 1.1) kJ . mol -1 , for 2-furancarbonitrile, 2-acetylfuran, and 3-furaldehyde, respectively. Standard molar enthalpies of formation are discussed in terms of the isomerization ortho meta. Enthalpic increment values of the introduction of the functional groups -CN, -CHO, and -COCH 3 were also compared with some other heterocycles; i.e. thiophene and pyridine

Piezoelectric Versus Conventional Rotary Techniques for Impacted Third Molar Extraction

Science.gov (United States)

Jiang, Qian; Qiu, Yating; Yang, Chi; Yang, Jingyun; Chen, Minjie; Zhang, Zhiyuan

2015-01-01

Abstract Impacted third molars are frequently encountered in clinical work. Surgical removal of impacted third molars is often required to prevent clinical symptoms. Traditional rotary cutting instruments are potentially injurious, and piezosurgery, as a new osteotomy technique, has been introduced in oral and maxillofacial surgery. No consistent conclusion has been reached regarding whether this new technique is associated with fewer or less severe postoperative sequelae after third molar extraction. The aim of this study was to compare piezosurgery with rotary osteotomy techniques, with regard to surgery time and the severity of postoperative sequelae, including pain, swelling, and trismus. We conducted a systematic literature search in the Cochrane Library, PubMed, Embase, and Google Scholar. The eligibility criteria of this study included the following: the patients were clearly diagnosed as having impacted mandibular third molars; the patients underwent piezosurgery osteotomy, and in the control group rotary osteotomy techniques, for removing impacted third molars; the outcomes of interest include surgery time, trismus, swelling or pain; the studies are randomized controlled trials. We used random-effects models to calculate the difference in the outcomes, and the corresponding 95% confidence interval. We calculated the weighted mean difference if the trials used the same measurement, and a standardized mean difference if otherwise. A total of seven studies met the eligibility criteria and were included in our analysis. Compared with rotary osteotomy, patients undergoing piezosurgery experienced longer surgery time (mean difference 4.13 minutes, 95% confidence interval 2.75–5.52, P piezosurgery groups. The number of included randomized controlled trials and the sample size of each trial were relatively small, double blinding was not possible, and cost analysis was unavailable due to a lack of data. Our meta-analysis indicates that although patients

Mandibular molar root morphology in Neanderthals and Late Pleistocene and recent Homo sapiens.

Science.gov (United States)

Kupczik, Kornelius; Hublin, Jean-Jacques

2010-11-01

Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n=127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M(1) and M(2) is small. In contrast, Aterian H. sapiens root surface areas peak at M(2). Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens. Copyright © 2010 Elsevier Ltd. All rights reserved.

[Evaluation of accuracy of virtual occlusal definition in Angle class I molar relationship].

Science.gov (United States)

Wu, L; Liu, X J; Li, Z L; Wang, X

2018-02-18

To evaluate the accuracy of virtual occlusal definition in non-Angle class I molar relationship, and to evaluate the clinical feasibility. Twenty pairs of models of orthognathic patients were included in this study. The inclusion criteria were: (1) finished with pre-surgical orthodontic treatment and (2) stable final occlusion. The exclusion criteria were: (1) existence of distorted teeth, (2) needs for segmentation, (3) defect of dentition except for orthodontic extraction ones, and (4) existence of tooth space. The tooth-extracted test group included 10 models with two premolars extracted during preoperative orthodontic treatment. Their molar relationships were not Angle class I relationship. The non-tooth-extracted test group included another 10 models without teeth extracted, therefore their molar relationships were Angle class I. To define the final occlusion in virtual environment, two steps were included: (1) The morphology data of upper and lower dentition were digitalized by surface scanner (Smart Optics/Activity 102; Model-Tray GmbH, Hamburg, Germany); (2) the virtual relationships were defined using 3Shape software. The control standard of final occlusion was manually defined using gypsum models and then digitalized by surface scanner. The final occlusion of test group and control standard were overlapped according to lower dentition morphology. Errors were evaluated by calculating the distance between the corresponding reference points of testing group and control standard locations. The overall errors for upper dentition between test group and control standard location were (0.51±0.18) mm in non-tooth-extracted test group and (0.60±0.36) mm in tooth-extracted test group. The errors were significantly different between these two test groups (P0.05); and the accuracy of non-tooth-extracted group was significantly smaller than 1 mm (Pdefinition of none class I molar relationship is higher than that of class I relationship, with an accuracy of 1 mm

Interfacial Properties of Methylcelluloses: The Influence of Molar Mass

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Pauline L. Nasatto

2014-12-01

Full Text Available The interfacial interactions of four methylcelluloses having the same average degree of substitution and distribution of methyl groups, but different molar masses, are studied at ambient temperature and at very low polymer concentrations. Firstly, the surface tension σ at the water/air interface is determined for the progressive addition of methylcellulose up to 100 mg/L; σ starts to decrease over 1 mg/L up to the critical aggregation concentration (CAC at 10 mg/L. The curves describing the influence of polymer concentration on σ are independent of the molar mass at equilibrium. Secondly, the adsorption of methylcellulose on silica particles is estimated from ζ-potential measurements. The data are interpreted in terms of an increase of the adsorbed layer thickness at the interface when the molar mass of methylcellulose increases. It is concluded that methylcellulose is adsorbed, forming trains and loops at the interface based on the equilibrium between surface free energy and solvent quality.

COMPLICATIONS AFTER EXTRACTION OF IMPACTED THIRD MOLARS - LITERATURE REVIEW

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Elitsa G. Deliverska

2016-07-01

Full Text Available Third molar surgery is the most common procedure performed by oral and maxillofacial surgeons worldwide. This article addresses the incidence of specific complications and, where possible, offers a preventive or management strategy. Complications, such as pain, dry socket, swelling, paresthesia of the lingual or inferior alveolar nerve, bleeding, and infection are most common. Factors thought to influence the incidence of complications after third molar removal include age, gender, medical history, oral contraceptives, presence of pericoronitis, poor oral hygiene, smoking, type of impaction, relationship of third molar to the inferior alveolar nerve, surgical time, surgical technique, surgeon experience, use of perioperative antibiotics, use of topical antiseptics, use of intra-socket medications, and anaesthetic technique. For the general dental practitioner, as well as the oral and maxillofacial surgeon, it is important to be familiar with all the possible complications after this procedure. This improves patient education and leads to prevention, early recognition and management.

3-D diagnosis-assisted management of anomalous mandibular molar

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Neelam Mittal

2012-01-01

Full Text Available This case report describes the successful non-surgical endodontic management of carious exposed three-rooted mandibular molar with four root canals detected on the pre-operative radiograph taken with 20 degrees mesial angulation and confirmed with a 64-slice helical computed tomography scan-assisted 3-D-reconstructed images. Access cavity shape was modified to locate the extra canal with respect to the distolingual root in the left mandibular first molar. Copious irrigation was accomplished with 5.25% sodium hypochlorite and 17% EDTA. Biomechanical preparation was done using protapers. Calcium hydroxide dressing was done for 1 week. The tooth was obturated using gutta percha and AH 26 root canal sealer, and it was permanently restored with composite. Clinical examination on follow-up visits revealed no sensitivity to percussion and palpation in the left mandibular first molar. Thorough knowledge of root canal variations and use of advanced diagnostic modalities lead to successful non-surgical management of the complex cases.

Pharmacokinetics and tolerability of a higher rifampin dose versus the standard dose in pulmonary tuberculosis patients.

NARCIS (Netherlands)

Ruslami, R.; Nijland, H.M.J.; Alisjahbana, B.; Parwati, I.; Crevel, R. van; Aarnoutse, R.E.

2007-01-01

Rifampin is a key drug for tuberculosis (TB) treatment. The available data suggest that the currently applied 10-mg/kg of body weight dose of rifampin may be too low and that increasing the dose may shorten the treatment duration. A double-blind randomized phase II clinical trial was performed to

Mandibular third molar development after mantle radiation in long-term survivors of childhood Hodgkin's disease

International Nuclear Information System (INIS)

McGinnis, J.P. Jr.; Hopkins, K.P.; Thompson, E.I.; Hustu, H.O.

1987-01-01

Sequential panoramic radiographs were assessed for mandibular third molar development in 47 long-term survivors of childhood Hodgkin's disease after treatment with 37 Gy mantle field radiation. To make a comparison, panoramic radiographs of 149 healthy, nonirradiated children were reviewed for the presence of mandibular third molars. In children between the ages of 7 and 12 years, bilateral agenesis of mandibular third molars was more frequent in patients who had been treated with mantle radiation than in nonirradiated patients. Unilateral agenesis, crown hypoplasia, and root growth impairment of mandibular third molars were also found. Similar, apparent, radiation-induced developmental anomalies were noted in maxillary third molars of the irradiated patients

Unilateral distalization of a maxillary molar with sliding mechanics: a case report.

Science.gov (United States)

Keles, Ahmet

2002-06-01

A unilateral Class II relationship could arise due to early loss of an upper second deciduous molar on one side during the mixed dentition period. This would allow the mesial drift of the molars, which may block the eruption of the second premolar. A 15-year 8-month-old male patient presented with a Class II molar relationship on the right, and Class I canine and molar relationship on the left side. His E was extracted when he was 5 years old. The 54 were impacted and the 3 was ectopically positioned due to the space loss from the mesial migration of the 76. In addition 21 1 were in cross-bite. Skeletally he had Class III tendency with low MMPA. He presented with a straight profile and retruded upper lip. For maxillary molar distalization, a newly developed 'Keles Slider' was used. The appliance was composed of one premolar and two molar bands, and the anchorage unit was composed of a wide Nance button. 46 were connected to the Nance button and, therefore, included into the anchorage unit. The point of distal force application was close to the centre of resistance of the 6 and parallel to the occlusal plane. Ni-Ti coil springs were used and 200 g of distal force was applied. Seven months later the space required for eruption of the permanent premolars and canine was regained, and the anterior cross-bite corrected. The appliance was removed and final alignment of the teeth was achieved with fixed appliances. At the end of the second phase treatment Class I molar and canine relationship was achieved on the both sides, the anterior cross-bite was corrected, inter-incisal angle was improved, and ideal overbite and overjet relationship was achieved. The active treatment time was 27 months.

Monte Carlo method for dose calculation due to oral X-rays; Coeficientes de conversao para calculo de doses devidos a radiografias odontologicas utilizando o metodo de Monte Carlo

Energy Technology Data Exchange (ETDEWEB)

Loureiro, Eduardo Cesar de Miranda

1998-06-01

The increasing utilization of oral X-rays, especially in youngsters and children, calls for the assessment of equivalent doses in their organs and tissues. With this purpose, a Monte Carlo code was adapted to simulate an X-ray source irradiating phantoms of the MIRD-5 type with different ages (10, 15 and 40 years old) to calculate the conversion coefficients which transform the exposure at skin to equivalent doses at several organs and tissues of interest. In order to check the computer program, simulations were performed for adult patients using the original code (ADAM.FOR developed at the GSF-Germany) and the adapted program (MCDRO.PAS). Good agreement between results obtained with both codes was observed. Irradiations of the incisive, canine and molar teeth were simulated. The conversion factors were calculated for the following organs and tissues: thyroid, active bone narrow (head and whole body), bone (facial skeleton, cranium and whole body), skin (head and whole body) and crystalline. Based on the obtained results, it follows that the younger the patient and the larger the field area, the higher the dose in assessed organs and tissues. The variation of the source-skin distance does not change the conversion coefficients. On the other hand, the increase in the voltage applied to the X-ray tube causes an increase in the calculated conversion coefficients. (author)

The incidence of cysts and tumors associated with impacted third molars

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A T Vigneswaran

2015-01-01

Full Text Available Incidence of cysts and tumors associated with lower impacted third molars are very low prevalence, which might be because of the fact that most pathologies go unnoticed as many practitioners discard the erupted tissue after surgical removal of the impacted teeth rather than sending the tissue for histopathological examination. Our aim was to evaluate the patients who came for third molar surgical removal with due therapeutic prophylacis and an incidental finding. A proper study protocol both inclusion and exclusion criteria was strictly followed for all the cases, which were included in the study. The period of study was 6 years and the total number of cases assessed were 2778 patients out of which 70 cases reported pathology associated with the impacted third molars. Among 70 cases 61.4% were reported as cyst and tumors and 38.6% of the cases had chronic inflammatory reaction, including two cases with normal dental follicle. High incidence rate of pathology associated with third molar occurred between age group of 20 and 30 years older age groups showed very low incidence. Most common site of impaction was found to be left side of mandible and positions were vertical and distoangular impactions. Thus was male predominance in the younger groups. The examination is necessary whether the third molars impacted cases were symptomatic or asymptomatic

Mineralization of mandibular third molars can estimate chronological age--Brazilian indices.

Science.gov (United States)

de Oliveira, Fernando Toledo; Capelozza, Ana Lúcia Álvares; Lauris, José Roberto Pereira; de Bullen, Izabel Regina Fischer Rubira

2012-06-10

Forensic age estimation is an important element of anthropological research, as it produces one of the primary sources of data that researchers use to establish the identity of a person living or the identity of unknown bodily remains. The aim of this study was to determine if the chronology of third molar mineralization could be an accurate indicator of estimated age in a sample Brazilian population. If so, mineralization could determine the probability of an individual being 18 years or older. The study evaluated 407 panoramic radiographs of males and females from the past 5 years in order to assess the mineralization status of the mandibular third molars. The evaluation was carried out using an adaptation of Demirjian's system. The results indicated a strong correlation between chronological age and the mineralization of the mandibular third molars. The results indicated that modern Brazilian generation tends to demonstrate an earlier mandibular third molar mineralization than older Brazilian generation and people of other nationalities. Males reached developmental stages slightly earlier than females, but statistically significant differences between the sex were not found. The probability that an individual with third molar mineralization stage H had reached an age of 18 years or older was 96.8-98.6% for males and females, respectively. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

P Elevator: An Innovatively Designed Elevator for Extraction of Third Molars.

Science.gov (United States)

Singh, Pradeep; Xiao, Shui Sheng; Ajmera, Deepal Haresh

2015-01-01

To modify the conventional straight elevator with a unique and innovative design in respect to approach and accessibility during extraction for patients with abrasions around corners of the mouth and with thick buccal mucosa, without causing overstretching of angles of the mouth. The shank of the straight elevator in the shape of a 'U' was modified, giving it a shape similar to 'P' in the English alphabet hence it is named the P Elevator. The P elevator utilises a 'U' shaped bend in the shank of the conventional straight elevator making space for the buccal soft tissues and the angle of the mouth, to accommodate properly in the 'U' shank. The application of this elevator in the successful removal of third molars is described. Two hundred patients underwent extraction of third molars with the P elevator including 166 patients with disimpaction of all third molars, 23 patients with abrasion around the angle of the mouth, and 11 patients with thick buccal mucosa. Satisfactory results were obtained in all the cases with no postoperative complications. The P elevator permits prudent, meticulous, innovative and proficient extraction of third molars in patients with thick buccal mucosa and abrasions around the angle of the mouth, without overstretching the corners of the mouth. We introduce novel applications of the P elevator in third molar extraction that provide substantial advantages over a conventional straight elevator.

Parsing partial molar volumes of small molecules: a molecular dynamics study.

Science.gov (United States)

Patel, Nisha; Dubins, David N; Pomès, Régis; Chalikian, Tigran V

2011-04-28

We used molecular dynamics (MD) simulations in conjunction with the Kirkwood-Buff theory to compute the partial molar volumes for a number of small solutes of various chemical natures. We repeated our computations using modified pair potentials, first, in the absence of the Coulombic term and, second, in the absence of the Coulombic and the attractive Lennard-Jones terms. Comparison of our results with experimental data and the volumetric results of Monte Carlo simulation with hard sphere potentials and scaled particle theory-based computations led us to conclude that, for small solutes, the partial molar volume computed with the Lennard-Jones potential in the absence of the Coulombic term nearly coincides with the cavity volume. On the other hand, MD simulations carried out with the pair interaction potentials containing only the repulsive Lennard-Jones term produce unrealistically large partial molar volumes of solutes that are close to their excluded volumes. Our simulation results are in good agreement with the reported schemes for parsing partial molar volume data on small solutes. In particular, our determined interaction volumes() and the thickness of the thermal volume for individual compounds are in good agreement with empirical estimates. This work is the first computational study that supports and lends credence to the practical algorithms of parsing partial molar volume data that are currently in use for molecular interpretations of volumetric data.

Root and Canal Morphology of Mandibular Third Molars in an Iranian Population

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Maryam Kuzekanani

2012-06-01

Full Text Available Background and aims. A through knowledge of the root canal morphology is required for successful endodontic therapy. The aim of this study was to investigate the root and canal morphology of mandibular third molars in Kerman, a province in southeast of Iran. Materials and methods. One-hundred-fifty extracted mandibular third molars were collected randomly from different dental clinics in Kerman. The root canal anatomy and morphology of each tooth was carefully studied using a clearing technique. Root number and morphology, number of canals per root, root canal configuration according to Vertucci classification, and incidence of dilacerated roots and C-shaped canals in mandibular third molars were evaluated under stereomicroscope with ×2 to ×3 magnifications. Results. From the total of 150 mandibular third molars studied, 21% had one root. The majority of teeth (73% had two roots. 5.5% of the teeth had three roots. The incidence of C-shaped canal was 3.5% in this study and 8% of the teeth had at least one dilacerated root. Conclusion. Although root canal anatomy and morphology of mandibular third molars is very variable having two roots seems to be the normal anatomy for these teeth.

[An 18 month evaluation of MM-MTA pulpotomy on primary decayed molars].

Science.gov (United States)

Abou Chedid, J C; Mchayleh, N; Khalil, I; Melki, B; Hardan, L S

2015-12-01

Pulpotomy is the most performed and controversial therapeutic in pediatric dentistry. Formocresol is known to have a toxic effect on living tissues, a mutagenic and carcinogenic potential with a systemic uptake of formocresol via pulpotomized teeth, other alternative products have been investigated. 40 molars were pulpotomized using Micro Mega Mineral Trioxide Aggregate (MM-MTA), which eliminates the need for the use of formocresol. The effects of this material were evaluated both clinically and radiographically. Post-operative control examinations were performed at 1, 6, 12, and 18 months trying to detect spontaneous or stimulated pain, pathological tooth mobility, abscesses or fistulas, internal or external pathological tooth resorption, periapical bone destruction, or canal obliteration. Pain was absent at 18 months post operatively. Thirty six molar treated with the MM-MTA didn't show any mobility or pain, one molar presented a pathological resorption and one molar presented an abscess without a fistula at 12 month. The observations were compared to others related to formocresol, ferric sulfate, MTA, and laser pulpotomies, using the Chi-square test x2. The abundance of positive result strongly demonstrate that the MM-MTA pulpotomy on carious temporary molars is a promising technique.

Avaliação da anatomia de molares decíduos por meio de microtomografia computadorizada

OpenAIRE

Ana Caroline Fumes

2013-01-01

O conhecimento prévio da anatomia interna e externa dos dentes decíduos é de fundamental importância para o sucesso do tratamento endodôntico. O objetivo do presente estudo foi analisar a morfologia das raízes e dos canais radiculares de molares decíduos superiores e inferiores, por meio de microtomografia computadorizada (micro-CT). Foram usados 40 molares decíduos, divididos em quatro grupos, sendo 10 primeiros molares inferiores, 10 segundos molares inferiores, 10 primeiros molares superio...

Analyses of superficial and depth doses in intraoral radiology

Energy Technology Data Exchange (ETDEWEB)

Silva Santos de Oliveira, C.; Morais, R.P. de; Nascimento Souza, D. do [Universidade Federal de Sergipe - CCET - Dept. de Fisica, Sao Cristovao, SE (Brazil)

2006-07-01

In this work dosimetric analysis using thermoluminescence technique to study the beams characteristics of x-rays employed in dental radiology has been carried out. The obtained results with CaSO{sub 4}:Dy thermoluminescent dosimeters (TLD) were compared to the doses obtained with parallel-plates ionization chamber. Dosimetric evaluations were also done using radiographic films of large dimensions. The x-rays equipments analyzed were installed in the radiological services of Odontology Department of Sergipe Federal University (U.F.S.). Depending on the anatomical region to be examined the proper exposure time was select, for a fix voltage of 70 kV. The results with TLD and ionization chamber have been determined to female and male individuals. The intraoral regions analysed were the peri apical of the incisors, molar and pre-molar teeth and the occlusive region. These regions were simulated using acrylic plates absorbers installed on the film packet holder. The evaluation of the depth doses in the intraoral tissue was obtained using different acrylic plate thickness. The air kerma values have been evaluated with the ionization chamber located in the dental cone exit of the x-rays equipments. The integrated areas of the thermoluminescent glow curves showed coherent values when compared to the ones obtained with the ionization chamber and both methods presented a linear dependence with the exposition time. The analyses with films have allowed the evaluation of the beam scattering in the simulator apparatus. The studies had proven that the analysis of superficial dose and in depth used in dental radiology can be carried with thermoluminescent dosimeters. (authors)

Analyses of superficial and depth doses in intraoral radiology

International Nuclear Information System (INIS)

Silva Santos de Oliveira, C.; Morais, R.P. de; Nascimento Souza, D. do

2006-01-01

In this work dosimetric analysis using thermoluminescence technique to study the beams characteristics of x-rays employed in dental radiology has been carried out. The obtained results with CaSO 4 :Dy thermoluminescent dosimeters (TLD) were compared to the doses obtained with parallel-plates ionization chamber. Dosimetric evaluations were also done using radiographic films of large dimensions. The x-rays equipments analyzed were installed in the radiological services of Odontology Department of Sergipe Federal University (U.F.S.). Depending on the anatomical region to be examined the proper exposure time was select, for a fix voltage of 70 kV. The results with TLD and ionization chamber have been determined to female and male individuals. The intraoral regions analysed were the peri apical of the incisors, molar and pre-molar teeth and the occlusive region. These regions were simulated using acrylic plates absorbers installed on the film packet holder. The evaluation of the depth doses in the intraoral tissue was obtained using different acrylic plate thickness. The air kerma values have been evaluated with the ionization chamber located in the dental cone exit of the x-rays equipments. The integrated areas of the thermoluminescent glow curves showed coherent values when compared to the ones obtained with the ionization chamber and both methods presented a linear dependence with the exposition time. The analyses with films have allowed the evaluation of the beam scattering in the simulator apparatus. The studies had proven that the analysis of superficial dose and in depth used in dental radiology can be carried with thermoluminescent dosimeters. (authors)

Molar macrowear reveals Neanderthal eco-geographic dietary variation.

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Luca Fiorenza

Full Text Available Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources.

Monte Carlo Method in the calculate of conversion coefficients for dose in children's organs and tissues subjected to dentistric radiography

International Nuclear Information System (INIS)

Loureiro, E.C.M.; Khoury, H.; Lima, F.R.A.

1998-01-01

The increasing utilization of oral X-rays, specially in youngsters and children, prompts the assessment of equivalent doses in their organs and tissues. With this purpose, Monte Carlo code was adopted to simulate an X-ray source irradiating phantoms of the MIRD-5 type with different ages (10, 15 and 40 years old) to calculate the conversion coefficients which transform the exposure at skin to equivalent doses at several organs and tissues of interest. In order to check the computer program, simulations were performed for adult patients using the original code (ADAM,FOR developed by GSF Germany) and the adapted program (MCDRO,PAS). Good agreement between results obtained by both programs was observed. Applications to incisive, canine and molar teeth were simulated. The conversion factors were calculated for the following organs and tissues: thyroid, active bone marrow (head and whole body), bone (facial skeleton, cranium and whole body), skin (head and whole body) and crystalline. Based on the obtained results, it follows that the younger the patient and the langer the field area, the higher the doses in assessed organs and tissues

Examining the interrelationship between DOC, bromide and chlorine dose on DBP formation in drinking water--a case study.

Science.gov (United States)

Bond, Tom; Huang, Jin; Graham, Nigel J D; Templeton, Michael R

2014-02-01

During drinking water treatment aqueous chlorine and bromine compete to react with natural organic matter (NOM). Among the products of these reactions are potentially harmful halogenated disinfection by-products, notably four trihalomethanes (THM4) and nine haloacetic acids (HAAs). Previous research has concentrated on the role of bromide in chlorination reactions under conditions of a given NOM type and/or concentration. In this study different concentrations of dissolved organic carbon (DOC) from U.K. lowland water were reacted with varying amounts of bromide and chlorine in order to examine the interrelationship between the three reactants in the formation of THM4, dihaloacetic acids (DHAAs) and trihaloacetic acids (THAAs). Results showed that, in general, molar yields of THM4 increased with DOC, bromide and chlorine concentrations, although yields did fluctuate versus chlorine dose. In contrast both DHAA and THAA yields were mainly independent of changes in bromide and chlorine dose at low DOC (1 mg·L(-1)), but increased with chlorine dose at higher DOC concentrations (4 mg·L(-1)). Bromine substitution factors reached maxima of 0.80, 0.67 and 0.65 for the THM4, DHAAs and THAAs, respectively, at the highest bromide/chlorine ratio studied. These results suggest that THM4 formation kinetics depend on both oxidation and halogenation steps, whereas for DHAAs and THAAs oxidation steps are more important. Furthermore, they indicate that high bromide waters may prove more problematic for water utilities with respect to THM4 formation than for THAAs or DHAAs. While mass concentrations of all three groups increased in response to increased bromide incorporation, only the THMs also showed an increase in molar yield. Overall, the formation behaviour of DHAA and THAA was more similar than that of THM4 and THAA. © 2013.

Prevalence, association, and sexual dimorphism of Carabelli's molar and shovel incisor traits amongst Jordanian population.

Science.gov (United States)

Khraisat, A; Taha, Sahar T; Jung, R E; Hattar, S; Smadi, L; Al-Omari, I K; Jarbawi, M

2007-09-01

The correlation between dental morphological traits can be used as an indicator to show major ethnic differences. Therefore, this study investigated the prevalence of Carabelli's molar and shovel incisor traits and tested their association and sexual dimorphism in Jordanian population. Three hundred subjects of school children at their 10th grade and of 15.5-year as an average age were involved. Alginate impressions for the maxillary arch were taken, poured, and casts were then trimmed. The selected accurate casts were of 132 male- and 155 female-students. The examined morphologic traits were Carabelli's trait on the maxillary first and second molars and shovel-shaped incisors. The relationship between different traits was investigated by Nonparametric Correlation analysis and Independent Sample t test was used to test sexual dimorphism in trait expression. The prevalence of Carabelli's trait in maxillary first molar and shovel trait in maxillary central incisor was relatively high (65.0 % and 53.0 %, respectively). The prevalence of Carabelli's trait on maxillary second molars was 3.8 %. Nonparametric Correlations revealed a strongest positive correlation between Carabelli's trait on maxillary first molar and shovel trait in males (P = 0.005). Significant sexual dimorphism was only found in the prevalence of Carabelli's trait on maxillary first molar (P = 0.013) and shovel trait (P = 0.038). The Jordanian Population had comparatively high prevalence of Carabelli's molar and shovel incisor traits. There was a positive association between Carabelli's trait on maxillary first molar and shovel trait in males. Sexual dimorphism was evident in Carabelli's trait on maxillary first molar and shovel trait.

Lower molar and incisor displacement associated with mandibular remodeling.

Science.gov (United States)

Baumrind, S; Bravo, L A; Ben-Bassat, Y; Curry, S; Korn, E L

1997-01-01

The purpose of this study was to quantify the amount of alveolar modeling at the apices of the mandibular incisor and first molar specifically associated with appositional and resorptive changes on the lower border of the mandible during growth and treatment. Cephalometric data from superimpositions on anterior cranial base, mandibular implants of the Björk type, and anatomical "best fit" of mandibular border structures were integrated using a recently developed strategy, which is described. Data were available at annual intervals between 8.5 and 15.5 years for a previously described sample of approximately 30 children with implants. The average magnitudes of the changes at the root apices of the mandibular first molar and central incisor associated with modeling/remodeling of the mandibular border and symphysis were unexpectedly small. At the molar apex, mean values approximated zero in both anteroposterior and vertical directions. At the incisor apex, mean values approximated zero in the anteroposterior direction and averaged less than 0.15 mm/year in the vertical direction. Standard deviations were roughly equal for the molar and the incisor in both the anteroposterior and vertical directions. Dental displacement associated with surface modeling plays a smaller role in final tooth position in the mandible than in the maxilla. It may also be reasonably inferred that anatomical best-fit superimpositions made in the absence of implants give a more complete picture of hard tissue turnover in the mandible than they do in the maxilla.

Relationship between post-extraction pain and acute pulpitis: a randomised trial using third molars.

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Zhang, Wei; Dai, Yong-Bo; Wan, Peng-Cheng; Xu, Dong-Dong; Guo, Yi; Li, Zhi

2016-12-01

The aim of the present study was to examine the relationship between post-extraction pain and acute pulpitis in third molars. This study was a randomised controlled trial. Sixty patients requiring removal of a single maxillary third molar with acute pulpitis were included and randomly divided into two groups: group A (n = 30); and group B (n = 30). In group A, third molars were directly extracted, and group B received endodontic therapy (pulp chamber opening and drainage) and underwent extraction 24 hours later, aiming to eliminate the acute inflammation. Another 30 patients requiring removal of a single maxillary third molar and with the same inclusion criteria but without caries or acute pulpitis were recruited into group C, in which the maxillary third molars were also directly extracted. The level of postoperative pain reported each day among the three groups was statistically evaluated. On the first, second and third days after surgery, there was a statistically significant difference between group A and group B and between group A and group C, but there was no statistically significant difference between group B and group C. The results of the present study indicate that there is more pain when third molars with acute pulpitis are directly removed compared with the pain level of the removal of third molars without acute pulpitis. © 2016 FDI World Dental Federation.

Standard molar enthalpies of formation of 1- and 2-cyanonaphthalene

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Lobo Ferreira, Ana I.M.C.; Barros, Ana L.M.; Bessa, Ana R.C.; Brito, Barbara C.S.A.; Vieira, Joana A.S.; Martins, Silvia A.P.

2011-01-01

Highlights: → Enthalpies of formation of 1- and 2-cyanonaphthalene were measured by combustion calorimetry. → Vapor pressures of crystalline 1- and 2-cyanonaphthalene obtained by Knudsen effusion mass loss technique. → Enthalpies, entropies and Gibbs functions of sublimation at T = 298.15 K were calculated. - Abstract: The standard (p o = 0.1 MPa) molar enthalpies of formation, in the crystalline state, of the 1- and 2-cyanonaphthalene were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static-bomb combustion calorimetry. Vapor pressure measurements at different temperatures, using the Knudsen mass loss effusion technique, enabled the determination of the enthalpy, entropy, and Gibbs energy of sublimation, at T = 298.15 K, for both isomers. The standard molar enthalpies of sublimation, at T = 298.15 K, for 1- and 2-cyanonaphthalene, were also measured by high-temperature Calvet microcalorimetry. (table) Combining these two experimental values, the gas-phase standard molar enthalpies, at T = 298.15 K, were derived and compared with those estimated by employing two different methodologies: one based on the Cox scheme and the other one based on G3MP2B3 calculations. The calculated values show a good agreement with the experimental values obtained in this work.

Experimental standard molar enthalpies of formation of some methylbenzenediol isomers

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Lobo Ferreira, Ana I.M.C.

2009-01-01

The present work is part of a research program on the energetics of formation of alkyl substituted benzenediols, aiming the study of the enthalpic effect of the introduction of methyl substituents into benzenediols. In this work we present the results of the thermochemical research on 2-methylresorcinol, 3-methylresorcinol, 4-methylresorcinol, and methylhydroquinone. The standard (p 0 =0.1MPa) molar enthalpies of formation, in the crystalline phase, at T = 298.15 K, of the compounds mentioned above were derived from their standard massic energies of combustion, measured by static-bomb combustion calorimetry, while the standard molar enthalpies of sublimation of those compounds were obtained by the temperature dependence of their vapour pressures determined by the Knudsen effusion technique. From experimental values, the standard molar enthalpies of formation of the studied methylbenzenediols in the gaseous phase, at T = 298.15 K were then derived. The results are interpreted in terms of structural contributions to the energetics of the substituted benzenediols and compared with the same parameters estimated from the Cox Scheme. Moreover, the standard (p 0 =0.1MPa) molar enthalpies, entropies, and Gibbs energies of sublimation, at T = 298.15 K, were derived for the four isomers of methylbenzenediols.

Modified Willet's appliance for bilateral loss of multiple deciduous molars: a case report.

Science.gov (United States)

Dhindsa, A; Pandit, I K

2008-09-01

No other factor plays a more significant role in preventive and interceptive dentistry than the preservation of deciduous dentition till its normal time of exfoliation. Premature loss of a deciduous tooth or a group of teeth might lead to wide range of implications. When the deciduous second molar is lost before the eruption of first permanent molar, intra-alveolar type of space maintainer is indicated. But in cases of bilateral loss of these teeth the conventional design generally poses a variety of problems. Thus, the conventional designs are required to be modified according to the needs of the patient. Therefore, this paper describes an entirely new design of the Willet's appliance in cases of bilateral loss of deciduous molars before the eruption of first permanent molar.

Root Canal Configuration of Maxillary First Permanent Molars in an Iranian Population

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Saeed Rahimi

2007-06-01

Full Text Available

Background and aims. It is critical to have a proper knowledge of the normal anatomy of the pulp and its variations for the success of endodontic treatment. The purpose of this study was to investigate variations in the root canal system of maxillary first permanent molars in an Iranian population.

Materials and methods. In this study, 137 maxillary first molars were decalcified, dye-injected, cleared and studied.

Results. The results demonstrated that 37.96% of the maxillary first molars under study had three canals, 58.4% had four canals and 3.64% had five canals.

Conclusion. According to the results of this study and considering variations in the root canal systems of maxillary first molars, it seems that great care should be taken in the root canal treatment of these teeth.

Experience versus complication rate in third molar surgery

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Al-Khawalde Mohammed

2006-05-01

Full Text Available Abstract Objectives The records of 1087 patients who underwent surgical removal of third molar teeth were prospectively examined to analyse the possible relationship between postoperative complications and the surgeon's experience parameter. Method and materials Seven surgeons (three specialists in surgical dentistry [specialists SD] and four oral and maxillofacial Senior House Officers [OMFS residents] carried out the surgical procedures. For each patient, several variables were recorded including age, gender, radiographic position of extracted teeth, treating surgeon, duration of surgery and postoperative complications. Results Analysis of the data revealed some differences in the incidence of complications produced by the specialists SD and OMFS residents. The main statistically relevant differences were increase the incidences of trismus, nerve paraesthesia, alveolar osteitis and infection in the resident-treated group, while the specialist-treated group showed higher rates of post-operative bleeding. Conclusion The higher rate of postoperative complications in the resident-treated group suggests that at least some of the complications might be related to surgical experience. Further work needs to compare specialists of training programmes with different years of experience, using large cross – sectional studies.

Radiographic assessment of third molars development and it's relation to dental and chronological age in an Iranian population.

Science.gov (United States)

Monirifard, Mohamad; Yaraghi, Navid; Vali, Ava; Vali, Asana; Vali, Amrita

2015-01-01

The aim of the present study was to estimate chronological age based on third molar development and to determine the association between dental age and third molar calcification stages. In this cross-sectional study, 505 digital panoramic radiographs of 223 males (44.2%) and 282 females (55.8%) between the age of 6 and 17 were selected from patients who were treated in Departments of Pediatrics and Orthodontics of Isfahan University of Medical Sciences between the years of 2009 and 2013. Correlation between chronological age and third molar development was analyzed with SPSS 21 using Spearman's Rank correlation coefficient, Chi-square test and multiple regression statistical tests (P third molars demonstrated a highly significant correlation with dental age (P age were mandibular left third molar in males and mandibular right third molar in females (r s = 0.072). When multiple regression was used to predict dental age based on molar calcification stage, the only significant correlation was between maxillary left third molar in males (P third molars in females. Relationship between chronological age and molars development stage was significant in all age subgroups and in both gender (P third molars and dental age in males. Results showed that third molar calcification stage can be used as an age predictor and in general mandibular teeth seems to be more reliable for this purpose in both genders and in all ages.

Comparison of Primary Molar Crown Dimensions with Stainless Steel Crowns in a Sample of Iranian Children

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Hossein Afshar

2015-06-01

Full Text Available Background and aims. Due to anatomic variation in tooth anatomy between populations, this study compared the buccolingual (BL and mesiodistal (MD dimensions of primary molars with those of stainless steel crowns (SSCs in anIranian population. Materials and methods. Impressions were taken from both dental arches of children, and casts were poured. Teeth with caries, restoration, hypoplasia or other dental anomalies were excluded. 216 primary molars were selected and divided into 4 groups of 54 each (maxillary and mandibular first and second primary molars. MD/BL dimensions were measured using a digital caliper with 0.01 mm precision on casts and SCCs (3M brand. Data were assessed using paired t-test, post hoc test and ANOVA. P < 0.05 was considered statistically significant. Results. The MD dimension of the lower first molar SSC and the BL dimension of the lower second molar SSC had the least difference with the corresponding values of the respective teeth. The MD dimension of the upper second molar SSC and the BL dimension of the upper first molar SSC had the greatest difference with the corresponding values in the respective teeth. Comparison of the two different brands of SSCs for the upper first molar revealed that both types had significant differences with the teeth in terms of both MD (P = 0.0 and BL (P = 0.0 dimensions. Conclusion. In the studied population, best adaptation was seen in second lower molars and the least adaptationswere seen in first and second upper molars.

Are hypomineralised lesions on second primary molars (HSPM) a predictive sign of molar incisor hypomineralisation (MIH)? A systematic review and a meta-analysis.

Science.gov (United States)

Garot, Elsa; Denis, Alice; Delbos, Yves; Manton, David; Silva, Mihiri; Rouas, Patrick

2018-05-01

Molar Incisor Hypomineralisation (MIH) and Hypomineralised Second Primary Molars (HSPM) involve qualitative structural developmental anomalies of tooth enamel affecting the first permanent molars (and often incisors) and the second primary molars, respectively. A putative relationship between HSPM and MIH has been reported in the scientific literature. The aim was to determine whether children with HSPM are more likely to develop MIH. A systematic search using PubMed/Medline, Embase and Cochrane Library electronic databases for publications from 2001 to August 2017 investigating the link between MIH and HSPM was undertaken. Four reviewers selected the studies independently, extracted the data according to PRISMA statement, and assessed the bias risk with the Newcastle-Ottawa Scale (NOS) criteria. From 645 potentially eligible studies, 14 were selected for full text analysis and 5 were included in the meta-analysis. Cross-sectional and cohort studies were reported and 4662 participants were included. The meta-analyses were performed with a random model calculated an OR total of 4.66 (95% CI 2.11-10.26; P MIH prevalence was 19.94%. The high heterogeneity (I 2  = 88%) can be explained by the great variation present in number of participants and variable caries risk. Despite the limitations of the study, the presence of HSPM is predictive for MIH, with greater MIH prevalence in the presence of mild HSPM. Early detection and preventive intervention could reduce MIH complications. Copyright © 2018 Elsevier Ltd. All rights reserved.

New quantitative classification of the anatomical relationship between impacted third molars and the inferior alveolar nerve

International Nuclear Information System (INIS)

Wang, Wei-Quan; Chen, Michael Y. C.; Huang, Heng-Li; Fuh, Lih-Jyh; Tsai, Ming-Tzu; Hsu, Jui-Ting

2015-01-01

Before extracting impacted lower third molars, dentists must first identify the spatial relationship between the inferior alveolar nerve (IAN) and an impacted lower third molar to prevent nerve injury from the extraction. Nevertheless, the current method for describing the spatial relationship between the IAN and an impacted lower third molar is deficient. Therefore, the objectives of this study were to: (1) evaluate the relative position between impacted lower third molars and the IAN; and (2) investigate the relative position between impacted lower third molars and the IAN by using a cylindrical coordinate system. From the radiology department’s database, we selected computed tomography images of 137 lower third molars (from 75 patients) requiring removal and applied a Cartesian coordinate system by using Mimics, a medical imaging software application, to measure the distribution between impacted mandibular third molars and the IAN. In addition, the orientation of the lower third molar to the IAN was also measured, but by using a cylindrical coordinate system with the IAN as the origin. According to the Cartesian coordinate system, most of the IAN runs through the inferior side of the third molar (78.6 %), followed by the lingual side (11.8 %), and the buccal side (8.9 %); only 0.7 % is positioned between the roots. Unlike the Cartesian coordinate system, the cylindrical coordinate system clearly identified the relative position, r and θ, between the IAN and lower third molar. Using the cylindrical coordinate system to present the relationship between the IAN and lower third molar as (r, θ) might provide clinical practitioners with a more explicit and objective description of the relative position of both sites. However, comprehensive research and cautious application of this system remain necessary

Hipomineralización incisivo Y molar: diagnóstico diferencial

OpenAIRE

Souza, Juliana Feltrin [UNESP; Jeremias, Fabiano [UNESP; Silva, Cristiane Maria da Costa [UNESP; Zuanon, Angela Cristina Cilense [UNESP; Santos-Pinto, Lourdes Aparecida Martins dos [UNESP; Cordeiro, Rita De Cássia Loiola [UNESP

2011-01-01

Hypomineralized first molar often in combination with hypomineralized incisors (MIH - molar incisor hypomineralization) is a common finding in everyday practice. In this condition, hypomineralized dental enamel is fragile and soft, and it can break easily leading to an exposed dentin, and causing dental sensitivity and progression of caries lesions. The prevalence of MIH range from 3.6 to 25% in North of Europe that consider this condition a public health problem. No conclusive information wa...

Experimental excess molar properties of binary mixtures of (3-amino-1-propanol + isobutanol, 2-propanol) at T = (293.15 to 333.15) K and modelling the excess molar volume by Prigogine–Flory–Patterson theory

International Nuclear Information System (INIS)

Kermanpour, F.; Niakan, H.Z.

2012-01-01

Highlights: ► Density and viscosity of binary mixtures of propanol derivatives were measured at T = (293.15 to 333.15) K. ► The excess molar properties were calculated from these experimental data and correlated by Redlich–Kister equation. ► The PFP model was applied for correlating the excess molar volumes. - Abstract: Density and viscosity of binary mixtures of (x 1 3-amino-1-propanol + x 2 isobutanol) and (x 1 3-amino-1-propanol + x 2 2-propanol) were measured over the entire composition range and from temperatures (293.15 to 333.15) K at ambient pressure. The excess molar volumes and viscosity deviations were calculated and correlated by the Redlich–Kister (RK) equation. The thermal expansion coefficient and its excess value, isothermal coefficient of excess molar enthalpy, and excess partial molar volumes were determined by using the experimental values of density and are described as a function of composition and temperature. The excess molar volumes are negative over the entire mole fraction range for both mixtures and increase with increasing temperature. The excess molar volumes obtained were correlated by the Prigogine–Flory–Patterson (PFP) model. The viscosity deviations of the binary mixtures are negative over the entire composition range and decrease with increasing temperature.

Poster - 56: Preliminary comparison of FF- and FFF-VMAT for prostate plans with higher rectal dose

International Nuclear Information System (INIS)

Liu, Baochang; Darko, Johnson; Osei, Ernest

2016-01-01

Purpose: A recent retrospective study found 53 patients previously treated to 78Gy/39 using flattened filtered (FF) 6X-VMAT at GRRCC had rectal DVH more than one standard deviation higher than the average. This study was to investigate if using 6FFFor10FFF beams could reduce these DVHs without compromising target coverage. Methods: Twenty patients’ plans were re-planed with 2-arc 6X-VMAT, 6FFF-VMAT and 10FFF-VMAT using the Eclipse TPS following departmental protocol. All plans had the same optimization and normalization, and were evaluated against the acceptance criteria from the QUANTEC and Emami. Statistical differences in the mean dose to OARs (D m ) and PTV homogeneity index (HI) between energies were tested using the paired sample Wilcoxon signed rank statistical method (p<0.05). Beam delivery accuracy was checked on five patients using portal dosimetry (PD). Results: The PTV HI for the 10FFF shows no statistical difference from the 6X. All the OARs, except left femoral head with 6FFF, have significantly lower Dm using 6FFF and 10FFF .There is no difference in the maximum doses to rectum and bladder and are limited by the prescribed doses. Measurements show good agreements in the gamma evaluation (3%/3mm) for all energies. Conclusion: This preliminary study shows that doses to the OARs are reduced using 10FFF for the same target coverage. The plans using 6FFF result in lower doses to some OARs, and statistically different PTV HI. All plans showed very good agreement with measurements.

Poster - 56: Preliminary comparison of FF- and FFF-VMAT for prostate plans with higher rectal dose

Energy Technology Data Exchange (ETDEWEB)

Liu, Baochang; Darko, Johnson; Osei, Ernest [Grand River Regional Cancer Centre, Kitchener, Ontario (Canada)

2016-08-15

Purpose: A recent retrospective study found 53 patients previously treated to 78Gy/39 using flattened filtered (FF) 6X-VMAT at GRRCC had rectal DVH more than one standard deviation higher than the average. This study was to investigate if using 6FFFor10FFF beams could reduce these DVHs without compromising target coverage. Methods: Twenty patients’ plans were re-planed with 2-arc 6X-VMAT, 6FFF-VMAT and 10FFF-VMAT using the Eclipse TPS following departmental protocol. All plans had the same optimization and normalization, and were evaluated against the acceptance criteria from the QUANTEC and Emami. Statistical differences in the mean dose to OARs (D{sub m}) and PTV homogeneity index (HI) between energies were tested using the paired sample Wilcoxon signed rank statistical method (p<0.05). Beam delivery accuracy was checked on five patients using portal dosimetry (PD). Results: The PTV HI for the 10FFF shows no statistical difference from the 6X. All the OARs, except left femoral head with 6FFF, have significantly lower Dm using 6FFF and 10FFF .There is no difference in the maximum doses to rectum and bladder and are limited by the prescribed doses. Measurements show good agreements in the gamma evaluation (3%/3mm) for all energies. Conclusion: This preliminary study shows that doses to the OARs are reduced using 10FFF for the same target coverage. The plans using 6FFF result in lower doses to some OARs, and statistically different PTV HI. All plans showed very good agreement with measurements.

Molar incisor hypomineralization in HIV-infected children and adolescents.

Science.gov (United States)

Andrade, Natália Silva; Pontes, Alessandra Silva; de Sousa Paz, Hélvis Enri; de Moura, Marcoeli Silva; Moura, Lúcia de Fátima Almeida de Deus; Lima, Marina de Deus Mourade

2017-01-01

The objective was to determine the prevalence of molar incisor hypomineralization (MIH) among individuals between 7 and 15 years old infected or noninfected with human immunodeficiency virus (HIV). The study was conducted with 33 HIV-infected individuals (study group; SG) and 66 non-HIV-infected schoolchildren (control group; CG), paired by gender and age. Data collection was based on medical records (SG), a questionnaire for caregivers and oral examination for diagnosis of MIH (European Academy of Pediatric Dentistry criteria) and caries (DMFT index and ICDAS). Data were analyzed with Mann-Whitney, chi-square, and Fisher's exact tests and logistic regression. In SG, MIH (45.5%) and caries (87.9%) had higher prevalence. MIH was associated with use of protease inhibitors in SG (OR: 2.14; 95% CI: 1.21 to 3.77) and incubator need in CG (OR: 2.80; 95% CI: 1.71 to 9.10). HIV-infected patients had a higher prevalence of MIH and dental caries in the permanent dentition. © 2016 Special Care Dentistry Association and Wiley Periodicals, Inc.

A New Orthodontic Appliance with a Mini Screw for Upper Molar Distalization.

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Ozkalayci, Nurhat; Yetmez, Mehmet

2016-01-01

The aim of this study is to present a new upper molar distalization appliance called Cise distalizer designed as intraoral device supported with orthodontic mini screw for upper permanent molar distalization. The new appliance consists of eight main components. In order to understand the optimum force level, the appliance under static loading is tested by using strain gage measurement techniques. Results show that one of the open coils produces approximately 300 gr distalization force. Cise distalizer can provide totally 600 gr distalization force. This range of force level is enough for distalization of upper first and second molar teeth.

Thermodynamic interrelation between excess limiting partial molar characteristics of a liquid nonelectrolyte

International Nuclear Information System (INIS)

Ivanov, Evgeniy V.

2012-01-01

Highlights: ► Excess limiting molar volume may be regarded as a solvation-related characteristic. ► Volumetric and enthalpic effects of dissolution are interrelated thermodynamically. ► Possibility to estimate the partial change in solute compressibility is described. - Abstract: On the basis of thermodynamic analysis, it is concluded that the excess limiting partial molar volume, like the excess limiting partial molar enthalpy, can be considered as a solvation-related characteristic of a liquid nonelectrolyte. A thermodynamically grounded interrelation between standard volumetric and enthalpic effects of solution of a liquid nonelectrolyte (or series of nonelectrolytes) is suggested.

Prevalence of three rooted permanent mandibular first molars in Haryana (North Indian population

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Alpa Gupta

2017-01-01

Full Text Available Background: Mandibular first molars typically have two roots but sometimes a supernumerary root presents distolingually called as radix entomolaris (RE. Aim: The present study evaluated the prevalence of permanent mandibular first molars featuring a distolingual root in Haryana (North India. Materials and Methods: Five hundred patients possessing bilateral mandibular first molars were selected for this study. The intraoral periapical radiographs were taken. The radiographs of these patients were evaluated under optimal conditions. A total of 1000 mandibular first molars were screened, and the incidence of three-rooted mandibular first molars, RE and the correlation between left and right side occurrence and between either gender were recorded. Statistical Analysis: The binary logistic regression test and Pearson's Chi-square test were used for statistical analysis. Results: The prevalence of three-rooted permanent mandibular first molars was 13% of the patients examined and 8.3% of the teeth examined. There was no statistically significant difference between gender and side of occurrence (P ≥ 0.05. The bilateral incidence of a symmetric distribution was 27.6 (18/65 among the RE teeth examined. Conclusion: RE is considered as an Asiatic trait. The occurrence of this macrostructure in the Haryana (North India population was found to be 13%. The clinician must thoroughly examine the radiographs before the initiation of endodontic therapy.

The maxillary second molar - anatomical variations (case report).

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Beshkenadze, E; Chipashvili, N

2015-01-01

To be acquainted with dental anatomical specificity is of great importance for dental endodontic treatment algorithm. The subject of present publication is 2 clinical cases of upper second molars, detailed characterization of, which is considered very important for enrichment of anatomical knowledge about dental anatomical variations. In one case, the reason for admission to the clinic of a 38-year-old woman was complains as of esthetic character as well as functional misbalance (disturbance of chewing function due to the damage of orthopedic construction). The patient indicated to the existence of coronary defects of large size aesthetic discomforts, damage and discolouration of old orthopedic construction (denture) in maxillary right molar area. According to the data obtained after clinical and visiographical examinations, chronic periodontitis of 17 teeth was identified as a result of incomplete endodontic treatment. According to the data obtained after clinical and visiographical examinations, the diagnosis of chronic periodontitis of 17 teeth was identified, tooth 17 with 2 roots and 2 canals. In the second clinical case, the reason for admission to the clinic of a 39-year-old woman was severe pain in the upper right molar area. The patient indicated to the caries on the tooth 17. After completion of proper survey clinical and visiographical examinations, acute pulpitis (K04.00) - with three roots and 4 canals was diagnosed. In both cases after the proper examinations and agreement with the patients a treatment plan envisaging: 17 teeth endodontic treatment, filling of caries defects and their preparation on one hand for orthopedic construction (denture) and on the other hand for restoration of anatomical integrity by light-cured composite, was scheduled. The present study is designed to prevent complications of endodontic treatment of the second molar, to optimize diagnosis and treatment algorithm, once again proving reliable information indicating to the

Immediate Placement of Ultrawide-Diameter Implants in Molar Sockets: Description of a Recommended Technique.

Science.gov (United States)

Hattingh, André C; De Bruyn, Hugo; Ackermann, Andrew; Vandeweghe, Stefan

Immediate implant placement is performed less frequently in molar extraction sockets than in single root sockets. This is mainly due to the tripodal anatomical configuration of molar roots, which is perceived as complex and therefore unsuitable. The mechanical burden of molar sites, combined with much larger socket dimensions, make it amenable to the use of ultrawide-diameter dental implants. This article describes a practical, sequenced technique that can be used predictably for immediate implant placement in maxillary and mandibular first molar sockets, using a dry skull model for clarification. This detailed description is based on the experience of more than 580 clinical cases over a 10-year period.

Twelve-month space changes after premature loss of a primary maxillary first molar.

Science.gov (United States)

Lin, Yai-Tin; Lin, Wen-Hsien; Lin, Yng-Tzer J

2011-05-01

Many early investigations concerning space changes following premature extraction of primary molars had a cross-sectional design, a small sample size, and a somewhat crude methodology, which may have led to misunderstandings. The aim of this study was to use established longitudinal data to investigate ongoing (12-month) dental-arch space problems arising as a result of premature loss of a primary maxillary first molar. Thirteen children (mean ± SD age at time of tooth extraction, 6.0 ± 0.74 years) with unilateral premature loss of a primary maxillary first molar were selected for this study. Maxillary dental study casts were obtained from participants 2 or 3 days after the tooth was removed, as well as at a follow-up appointment 12 months later. Six reference lines were measured on the study cast: D + E space, arch width, arch length, intercanine width, intercanine length, and arch perimeter. For each participant, the D + E space of the contralateral intact primary molar served as a control. A paired t-test was used to compare the cast measurements between initial examination and 12-month follow-up. A t-test was used to compare D + E space changes with those of the control group. The D + E space of the extraction side after 12 months was significantly smaller than that of the control side (P 0.05). The 12-month space changes in the maxillary dental arch after premature loss of a primary maxillary first molar consist mainly of distal drift of the primary canine toward the extraction site. Mesial movement of permanent molars or tilting of the primary molars did not occur. An increased arch dimension was found especially in the anterior segment (intercanine width and length). There is no need for the use of space maintainers from the results in this study in cases of premature loss of a primary first molar. © 2010 The Authors. International Journal of Paediatric Dentistry © 2010 BSPD, IAPD and Blackwell Publishing Ltd.

Molar volume dependence of the pressure of solid 3He at very low temperatures

International Nuclear Information System (INIS)

Mamiya, T.; Sawada, A.; Fukuyama, H.; Iwahashi, K.; Masuda, Y.

1983-01-01

The pressure of solid 3 He has been measured as a function of temperature T between 0.3 and 50 mK at molar volumes between 24.19 and 23.31 cm 3 . The entropy discontinuity obtained from the pressure jump at the ordering transition turned out to be almost independent of molar volumes, being about 0.40Rln2 in the studied range of molar volumes

Influência da temperatura, da massa molar e da distribuição de massa molar na tensão superficial de PS, PP e PE: experimento e teoria

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Moreira José C.

2003-01-01

Full Text Available Neste trabalho a influência da temperatura, da massa molar (n e da distribuição de massa molar (MWD na tensão superficial de poliestireno (PS foi avaliada utilizando o método da gota pendente. A influência da temperatura na tensão superficial de polipropileno isotático (i-PP e de polietileno de baixa densidade (PELBD também foi estudada aqui. As teorias de Patterson-Rastogi e Dee-Sauer foram utilizadas em conjunção com a teoria de equação de estado de Flory, Orwoll, e Vrij (FOV para prever a tensão superficial (gama utilizando dados de pressão-volume-temperatura (PVT dos polímeros. Ambas teorias prevêem que a tensão superficial diminui linearmente com o aumento da temperatura e aumenta com a massa molar concordando com os resultados experimentais. Entretanto, ambas teorias subestimam a mudança de entropia de formação de superfície por unidade de área a volume constante para sistemas poliméricos de baixa massa molar e polidisperso e subestimam o efeito da distribuição de massa molar na tensão superficial

Risk Factors and Dose-Effect Relationship for Mandibular Osteoradionecrosis in Oral and Oropharyngeal Cancer Patients

International Nuclear Information System (INIS)

Lee, Ik Jae; Koom, Woong Sub; Lee, Chang Geol; Kim, Yong Bae; Yoo, Sei Whan; Keum, Ki Chang; Kim, Gwi Eon; Choi, Eun Chang; Cha, In Ho

2009-01-01

Purpose: To analyze risk factors and the dose-effect relationship for osteoradionecrosis (ORN) of the mandible after radiotherapy of oral and oropharyngeal cancers. Materials and Methods: One-hundred ninety-eight patients with oral (45%) and oropharyngeal cancer (55%) who had received external radiotherapy between 1990 and 2000 were retrospectively reviewed. All patients had a dental evaluation before radiotherapy. The median radiation dose was 60 Gy (range, 16-75 Gy), and the median biologically effective dose for late effects (BED late ) in bone was 114 Gy 2 (range, 30-167 Gy 2 ). Results: The frequency of ORN was 13 patients (6.6%). Among patients with mandibular surgery, eight had ORN at the surgical site. Among patients without mandibular surgery, five patients had ORN on the molar area of the mandible. The median time to ORN was 22 months (range, 1-69 months). Univariate analysis revealed that mandibular surgery and Co-60 were significant risk factors for ORN (p = 0.01 and 0.04, respectively). In multivariate analysis, mandibular surgery was the most important factor (p = 0.001). High radiation doses over BED 102.6 Gy 2 (conventional dose of 54 Gy at 1.8 Gy/fraction) were also a significant factor for ORN (p = 0.008) and showed a positive dose-effect relationship in logistic regression (p = 0.04) for patients who had undergone mandibular surgery. Conclusions: Mandibular surgery was the most significant risk factor for ORN of mandible in oral and oropharyngeal cancers patients. A BED of 102.6 Gy 2 or higher to the mandible also significantly increases the risk of ORN.

Evaluation of third molar development and its relation to chronological age: a panoramic radiographic study.

Science.gov (United States)

Zandi, Mohammad; Shokri, Abbas; Malekzadeh, Hamid; Amini, Payam; Shafiey, Parastu

2015-06-01

Third molar development, in comparison to other teeth in the dentition, has the greatest variation in morphology, anatomical position, and time of development and eruption, and its reliability for chronological age estimation is controversial. The aim of the present study was to evaluate third molar development and its relation to chronological age using panoramic radiography. A total of 2536 digital panoramic radiographs of individuals aged between 5 and 26 years were selected. The developmental status of the third molars was assessed using eight-stage developmental scoring proposed by Demirjian et al., with one modification: a stage 0 was added. The collected data were entered into a checklist and subjected to statistical analyses. The mean ages of the first appearance of third molar bud, complete crown formation, and root apex closure were around 9, 14, and 22 years, respectively. In both jaws, third molar development occurred symmetrically, and sexual dimorphism was observed at some developmental stages. Finally, two formulas were presented to estimate age of the juveniles and adolescents based on their gender and developmental stages of the third molars, and validated on a second sample consisting of 523 individuals aged between 8 and 22. Assessment of third molar development was found to be a reliable method for age estimation of individuals between 11 and 22 years. Because of possible ethnic and geographic differences in third molar development, population specific researches were recommended.

Standard molar enthalpies of formation of sodium alkoxides

International Nuclear Information System (INIS)

Chandran, K.; Srinivasan, T.G.; Gopalan, A.; Ganesan, V.

2007-01-01

The molar enthalpies of solution of sodium in methanol, ethanol, and n-propanol and of sodium alkoxides in their corresponding alcohols were measured at T=298.15K using an isoperibol solution calorimeter. From these results and other auxiliary data, the standard molar enthalpies of formation, Δ f H m o (RONa,cr) of sodium methoxide, sodium ethoxide, and sodium n-propoxide were calculated and found to be {(-366.21+/-1.38) (-413.39+/-1.45), and (-441.57+/-1.18)}kJ.mol -1 , respectively. A linear correlation has been found between Δ f H m o (RONa)andΔ f H m o (ROH) for R=n-alkyl, enabling the prediction of data for other sodium alkoxides

Apparent molar volumes and compressibilities of lanthanum, gadolinium and lutetium trifluoromethanesulfonates in dimethylsulfoxide

International Nuclear Information System (INIS)

Warmińska, Dorota; Wawer, Jarosław

2012-01-01

Highlights: ► Sequence of volumes and compressibilities of Ln 3+ ions in DMSO is: La 3+ > Gd 3+ 3+ . ► Sequence of the partial molar volumes do not change with temperature. ► These results are the consequence of nature of the ion–solvent bonding. - Abstract: Temperature dependencies of the densities of dimethylsulfoxide solutions of lanthanum, gadolinium and lutetium trifluoromethanesulfonates have been determined over a wide range of concentrations. The apparent molar volumes and partial molar volumes of the salts at infinite dilution, as well as the expansibilities of the salts, have been calculated from density data. Additionally, the apparent molar isentropic compressibilities of lanthanum, gadolinium and lutetium trifluoromethanesulfonates have been calculated from sound velocity data at 298.15 K. The data obtained have been interpreted in terms of ion−solvent interactions.

Association between third mandibular molar impaction and degree of root development in adolescents

DEFF Research Database (Denmark)

Lauesen, Søren Rødsgaard; Andreasen, Jens O; Gerds, Thomas Alexander

2013-01-01

of the mandibular third molar region from 132 subjects (71 male and 61 female) from 15 to 20 years of age. Based on the films, 264 lower third molars were classified into an eruption and an impaction group. Root development was recorded according to a quantitative method described by Haavikko (1970......: Delayed mandibular third molar root development is associated with impaction. Radiographs taken at age 15 may predict the risk of impaction and thereby guide decision making for the orthodontist or the oral and maxillofacial surgeon.......Abstract Objective: To compare the root development and the growth rate of the mandibular third molar (M3 inf) in individuals where the M3 inf erupted vs individuals exhibiting M3 inf impaction. Materials and Methods: Serial standardized intraoral radiographs (Eggen technique) were taken annually...

Management of early loss of first permanent molar: A new technique

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B S Rajashekhara

2012-01-01

Full Text Available The loss of a permanent first molar in adolescent patient creates a need for early space maintenance and restoration of function. To ascertain function and esthetics, immediate treatments include interim restorative approaches. This paper describes a conservative, functional and cost-effective bridge as an interim restoration after the loss of permanent first molar in an early adolescent dentition.

Morphology and chemical composition of dentin in permanent first molars with the diagnose MIH.

Science.gov (United States)

Heijs, Suzanne C B; Dietz, Wolfram; Norén, Jörgen G; Blanksma, Nynke G; Jälevik, Birgitta

2007-01-01

The purpose of this investigation was to study the morphology and distribution of some inorganic elements in dentin in first permanent molars from children with Molar-Incisor Hypomineralization (MIH). Sixty four tooth sections from thirty two children were examined in polarized light. Fifteen representative sections were selected for SEM/XRMA analysis; 5 were used for SEM analysis and 10 for XRMA analysis. No morphological changes in the dentin were revealed in polarized light microscopy (PLM). However, in all but two sections interglobular dentin was found. The SEM analyzes confirmed the findings of the PLM with no structural changes to be found in the dentin. The XRMA results showed a difference in the concentration of elements between dentin below normal and dentin below carious or hypomineralized enamel. Elements related to organic matter appeared with higher values in dentin below hypomineralized and carious enamel. The morphological and chemical findings in dentin below hypomineralized enamel imply that the odontoblasts are not affected in cases of MIH, but may be affected by hypocalcemia, reflected by the presence of interglobular dentin.

Effect of Submucosal Injection of Dexamethasone on Post-operative Sequelae of Third Molar Surgery

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S P Deo

2011-06-01

Full Text Available Introduction: This study was carried out to evaluate the effects of a single pre-operative sub-mucosal injection of dexamethasone after third molar surgery to see the effects on post-operative discomfort. Methods: This study was a prospective, double-blind, randomized, clinical trial. The subjects were forty patients who underwent surgical removal of the mandibular impacted third molar under local anesthesia and after being randomly assigned to receive either an 8 mg dexamethasone as submucosal injection or a normal saline injection into the lower buccal vestibule adjacent to the third molar. The maximum interincisal distance and facial contours were measured at the baseline and post-surgically on Day 2 and 7. Post-operative pain was evaluated subjectively using a visual analog scale and objectively by counting the number of analgesic tablets used. All subjects were operated upon by the same investigator to minimize the difference from inter-operator variability. Results: There was a signicant difference in the measurements of the degree of swelling and trismus between the two groups on the 2nd post-operative day. In contrast, there was no statistically signicant difference between the groups on the 7th post-operative day. The test group also used fewer analgesics post-operatively. Conclusions: Submucosal injection of dexamethasone after third molar surgery is effective in reducing postoperative swelling and trismus. It also delays the onset of post-operative pain. Keywords: dexamethasone, submucosal injection, third molar, third molar surgery, third molar extraction

Third molars and periodontal pathology in American adolescents and young adults: a prevalence study.

Science.gov (United States)

Blakey, George H; Gelesko, Savannah; Marciani, Robert D; Haug, Richard H; Offenbacher, Steven; Phillips, Ceib; White, Raymond P

2010-02-01

To assess the association between visible third molars and the prevalence of periodontal inflammatory disease of non-third molars. Subjects aged 14 to 45 years with 4 asymptomatic third molars were enrolled in an institutional review board-approved study. Subjects were classified based on whether at least 1 third molar was visible or all third molars were not visible. Full-mouth periodontal probing depth (PD) data, with 6 sites per tooth, were obtained as a measure of a subject's periodontal status. At least 1 non-third molar PD of 4 mm or greater was indicative of periodontal inflammatory disease. Outcomes for the respective groups were compared by use of Cochran-Mantel-Haenszel row mean score statistics. The level of significance for differences was set at .05. The 342 subjects in the visible group were significantly older, with a median age of 26 years (interquartile range, 22.4-32.2 years), as compared with the 69 subjects in the not visible group, with a median age of 21 years (interquartile range, 18.8-24.9 years) (P .05). Most subjects were white. Significantly more subjects with at least a college education were in the visible group than in the not visible group (P adolescents and young adults was significantly associated with periodontal inflammatory disease of non-third molars. Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

CT analyses of the location of the maxillary third molar in relation to panoramic radiographic appearance

International Nuclear Information System (INIS)

Obayashi, Naofumi; Ariji, Yoshiko; Goto, Masakazu; Izumi, Masahiro; Naitoh, Munetaka; Kurita, Kenichi; Shimozato, Kazuo; Ariji, Eiichiro

2009-01-01

We compared the relationship between anatomical structures analyzed by panoramic radiographs and CT images of uninfected impacted maxillary third molars and investigated the pathway of infection originating from pericoronitis of maxillary third molars. Patients (n=62) with uninfected impacted maxillary third molars and patients (n=8) with odontogenic infection originating from pericoronitis of the maxillary third molars were selected from an image database. CT and panoramic images were evaluated separately by an oral surgeon and a radiologist for the vertical position of the tooth, the presence of bone around the crown, proximity to the maxillary sinus, visibility of masticatory muscles, and mesiodistal and buccopalatal inclinations. In uninfected patients, a significant correlation was observed between the vertical positions evaluated by the two methods. Of the third molars, 79 (63.7%) were identified as vertical type on both panoramic and CT images. Regarding the maxillary sinus, of the 19 molars classified as the separate type on panoramic images, 2 (10.5%) were identified as the close type on CT. CT examination revealed the involvement of buccal cortical plates and the buccal space in the majority of infected patients. CT images revealed that 94 molars (75.8%) showed vertical type on the buccopalatal inclination and that 45 impacted molars (36.3%) showed bone defects in the buccal area. Infections originating from pericoronitis of the maxillary third molar showed involvement of the buccal cortical plates, the buccal space, and other spaces, which were clearly depicted on CT images. (author)

Bilateral maxillary fused second and third molars: a rare occurrence

OpenAIRE

Liang, Rui-Zhen; Wu, Jin-Tao; Wu, You-Nong; Smales, Roger J; Hu, Ming; Yu, Jin-Hua; Zhang, Guang-Dong

2012-01-01

This case report describes the diagnosis and endodontic therapy of maxillary fused second and third molars, using cone-beam computed tomography (CBCT). A 31-year-old Chinese male, with no contributory medical or family/social history, presented with throbbing pain in the maxillary right molar area following an unsuccessful attempted tooth extraction. Clinical examination revealed what appeared initially to be a damaged large extra cusp on the buccal aspect of the distobuccal cusp of the secon...

Agenesia de terceros molares en pacientes de la Facultad de Odontología de la UNAM Agenesia of the third molars in patients of the Faculty of Odontology of the National Autonomous University of Mexico

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Raúl Díaz Pérez

2008-12-01

Full Text Available ANTECEDENTES: los terceros molares o serotinos son los últimos dientes en erupcionar; su presencia genera diversas patologías como apiñamiento, pericoronitis y dolor, generalmente por falta de espacio en los maxilares. Según la filogenia humana son considerados dientes en vías de extinción. Cada vez más presentan una erupción retrasada e incluso ausencia por falta de formación. OBJETIVO: determinar la frecuencia de agenesia de terceros molares en pacientes de la Facultad de Odontología de la Universidad Nacíonal Autónoma de México. MÉTODOS: se examinaron 915 ortopantomografías de pacientes de 16 a 24 años y se realizó el diagnóstico de presencia de los terceros molares, se recabó información sociodemográfica y se analizó la asociación con el sexo usando X². RESULTADOS: el 20 % de la muestra presentó agenesia de los 4 terceros molares, 56 % tuvo los 4, y 24 % solo de 1 a 3, además se encontró que el sexo no determina la presencia de los terceros molares (X²= 0,503, p= 0,478. CONCLUSIONES: la frecuencia de agenesia de terceros molares fue del 20 % y esta es independiente del sexo.ANTECEDENTS: the third molars are the last teeth to erupt. Their presence generate diverse pathologies as crowding, pericoronitis and pain, generally due to the lack of space in the maxillae. According to human phylogeny, they are considered teeth on the way to extinction. They present an increasingly delayed eruption and even absence due to lack of formation, OBJECTIVE: to determine the frequency of agenesia of the third molars in patients of the Faculty of Odontology of the National Autonomous University of Mexico. METHODS: 915 orthopantomographies of patients aged 16-24 were examined and the diagnosis of presence of the third molars was made. Sociodemographic information was necessary and the association with sex was analyzed by using X2. RESULTS: 20 % of the sample presented agenesia of the 4 third molars, 56 % had the 4, and 24 % only from

Utilization of the higher plants in a study on hereditary effect of low-dose irradiation

International Nuclear Information System (INIS)

Yamashita, Jun

1976-01-01

Some problems in a study of hereditary effect of low-dose irradiation, which used the higher plants (tradescantia, peas, etc.) as materials, were mentioned. Conditions to be used as materials were mentioned as follows: 1) the materials must have high radio-sensitivity, 2) the natural mutation of the materials must be low, 3) hereditary uniformity and stability of genes in the materials were important, and 4) in case of considering the materials as environmental radiation monitors, the observation period must be long and the duration from exposure to detection of mutation must be short. Tradescantia has most of these conditions, but the greatest fault is that the object of its observation is mutation of somatic cells, and hereditary study is impossible. Therefore, it is necessary to find out other materials in order to solve the problem whether there is a difference in relative frequency of chromosomal abnormalities, which occurrs in germinal cells and is transmitted to posterity, between low and high doses or not. (Serizawa, K.)

Variable permanent mandibular first molar: Review of literature

Science.gov (United States)

Ballullaya, Srinidhi V; Vemuri, Sayesh; Kumar, Pabbati Ravi

2013-01-01

Introduction: The success of root canal therapy depends on the locations of all the canals, thourough debridement and proper sealing. At times the clinicians are challenged with variations in morphology of root canal. This review article attempts to list out all the variations of permanent mandibular first molar published so for in the literature. Materials and Methods: An exhaustive search was undertaken using PUBMED database to identify published literature from 1900 to 2010 relating to the root canal morphology of permanent first molar by using key words. The selected artcles were obtained and reviewed. Results: Total ninty seven articles were selected out of which 50 were original article and forty seven were case reports. The incidence of third canal in mesial root was 0.95% to 15%. The incidence of three rooted mandibular first molar was 3% to 33%. Only ninety cases reported with c-shape canal configuration. Incidence of Taurodintism without congenital disorder was very rare. Conclusion: The root canal treatment requires proper knowlegde of variations in root canal morphology in order to recognise, disinfect and seal all portal of exit. This can be accomplished with proper diagnosis using newer modes, modification in access preparation, use of operating microscope, enhanced methods of disinfecting and sealing of all canals. PMID:23716959

Changes in the Position of Mandibular Third Molars Following Extraction and Non-Extraction Orthodontic Treatments

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Maryam Poosti

2012-09-01

Full Text Available Introduction: Impaction of third molars can be associated with a number of sequelae, each requiring a different type of treatment. The purpose of this study was to assess the changes in the position of lower third molars following extraction and non-extraction orthodontic treatments. Methods: Pre- and post-treatment panoramic radiographs of 26 class I malocclusion patients (4 male and 22 female who were treated on a non-extraction basis were compared with those of 30 class I malocclusion patients (5 male and 25 female who received orthodontic treatment following the extraction of all first premolars. In each group, the lower third molar angulations and their distance from the lower border of the mandible were assessed. Results: Paired t-tests and independent t-tests detected significant changes in the position of the lower third molars in the extraction group. Both the left and right molars became more upright and their distance from the lower border of the mandible increased. Similar changes were only seen in the position of the right mandibular third molars in the non-extraction group. Conclusion: Tooth extractions can bring about favorable changes in the position of mandibular third molars and possibly reduce their incidence of impaction.

Changes in the Position of Mandibular Third Molars Following Extraction and Non-Extraction Orthodontic Treatments

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Maryam Poosti

2013-01-01

Full Text Available Introduction: Impaction of third molars can be associated with a number of sequelae, each requiring a different type of treatment. The purpose of this study was to assess the changes in the position of lower third molars following extraction and non-extraction orthodontic treatments. Methods: Pre- and post-treatment panoramic radiographs of 26 class I malocclusion patients (4 male and 22 female who were treated on a non-extraction basis were compared with those of 30 class I malocclusion patients (5 male and 25 female who received orthodontic treatment following the extraction of all first premolars. In each group, the lower third molar angulations and their distance from the lower border of the mandible were assessed. Results: Paired t-tests and independent t-tests detected significant changes in the position of the lower third molars in the extraction group. Both the left and right molars became more upright and their distance from the lower border of the mandible increased. Similar changes were only seen in the position of the right mandibular third molars in the non-extraction group. Conclusion: Tooth extractions can bring about favorable changes in the position of mandibular third molars and possibly reduce their incidence of impaction

Opciones de tratamiento en un paciente con pérdida prematura de segundos molares primarios: zapato distal modificado / Treatment Options in a Patient with Primary Second Molar Premature Loss: Modified Distal Shoe Space Maintainer

OpenAIRE

Cardoso, María Lorena; Universidad Nacional del Nordeste. Corrientes, Argentina; Falcón, Diana Emilia; Universidad Nacional del Nordeste. Corrientes, Argentina; Galiana, Andrea Verónica; Universidad Nacional del Nordeste. Corrientes, Argentina

2017-01-01

RESUMEN. Antecedentes: La pérdida prematura de un molar primario conlleva a malposición de los dientes contiguos y del sucesor permanente. El efecto depende de las fuerzas que actúan sobre el diente, que están condicionadas a su vez por el estado de erupción del primer molar permanente. Propósito: Describir una opción de tratamiento para la pérdida prematura de segundos molares primarios hasta la erupción de los primeros molares permanentes. Descripción del caso: El caso clínico presentado in...

Evaluation of third molar development in the estimation of chronological age.

Science.gov (United States)

Soares, Caio Belém Rodrigues Barros; Figueiroa, José Natal; Dantas, Renata Moura Xavier; Kurita, Lúcio Mitsuo; Pontual, Andréa dos Anjos; Ramos-Perez, Flávia Maria de Moraes; Perez, Danyel Elias da Cruz; Pontual, Maria Luiza dos Anjos

2015-09-01

The purpose of this study was to evaluate the correlation between chronological age and the degree of third molar mineralization by Demirjian's developmental stages (Demirjian et al., 1973) using panoramic radiography. From a total of 11.396 digital panoramic radiographs of patients from three oral radiology private clinics from the northeast region of Brazil, obtained from January to June 2009, 2097 radiographic images from patients aged between 6 and 22 years were selected. The images were analyzed individually by two obsevers using a 21-inch computer screen and Windows Picture and Fax Viewer. Reliability was achieved by intra- and interobserver evaluation, using the Kappa test. Chronological age, calcification stage, gender and third molar were interrelated using a multiple linear regression model, considering age as a response variable. There was reliability with Demirjian et al.'s developmental stage assesment, displaying a significant relationship between mineralization stages and patients' age (Page and the calcification stage taking gender and localization of the third molar into consideration. It is possible to estimate chronological age based on Demirjian's stage of a third molar, regardless of gender and location. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Thermodynamic properties of binary mixtures of tetrahydropyran with pyridine and isomeric picolines: Excess molar volumes, excess molar enthalpies and excess isentropic compressibilities

International Nuclear Information System (INIS)

Saini, Neeti; Jangra, Sunil K.; Yadav, J.S.; Sharma, Dimple; Sharma, V.K.

2011-01-01

Research highlights: → Densities, ρ and speeds of sound, u of tetrahydropyran (i) + pyridine or α-, β- or γ-picoline (j) binary mixtures at 298.15, 303.15 and 308.15 K and excess molar enthalpies, H E of the same set of mixtures at 308.15 K have been measured as a function of composition. → The observed densities and speeds of sound values have been employed to determine excess molar volumes, V E and excess isentropic compressibilities, κ S E . → Topology of the constituents of mixtures has been utilized (Graph theory) successfully to predict V E , H E and κ S E data of the investigated mixtures. → Thermodynamic data of the various mixtures have also been analyzed in terms of Prigogine-Flory-Patterson (PFP) theory. - Abstract: Densities, ρ and speeds of sound, u of tetrahydropyran (i) + pyridine or α-, β- or γ- picoline (j) binary mixtures at 298.15, 303.15 and 308.15 K and excess molar enthalpies, H E of the same set of mixtures at 308.15 K have been measured as a function of composition using an anton Parr vibrating-tube digital density and sound analyzer (model DSA 5000) and 2-drop micro-calorimeter, respectively. The resulting density and speed of sound data of the investigated mixtures have been utilized to predict excess molar volumes, V E and excess isentropic compressibilities, κ S E . The observed data have been analyzed in terms of (i) Graph theory; (ii) Prigogine-Flory-Patterson theory. It has been observed that V E , H E and κ S E data predicted by Graph theory compare well with their experimental values.

How serious is Molar Incisor Hypomineralisation (MIH) among 8- and 9-year-old children in Bosnia-Herzegovina? A clinical study.

Science.gov (United States)

Mulic, A; Cehajic, E; Tveit, A B; Stenhagen, K R

2017-06-01

To determine the prevalence of MIH in 8- and 9 year-old children in the city of Kljuc, Bosnia-Herzegovina, and to describe the distribution and severity of the affected teeth. Study design: All 8- and 9-year-olds (n=104) living in Kljuc (born 2004/2005) were invited to participate, and 103 were examined by a calibrated clinician. Written, informed consent was obtained from all participants' relatives, as well as a questionnaire designed to assess potential risk indicators. Index teeth were all permanent first molars and incisors (12 teeth). Opacities (>1mm), post eruptive breakdown (PEB), atypical restorations and previous extractions caused by MIH were registered. The prevalence of MIH was 11.7% (n=12), significantly higher for girls than for boys (14.6% vs. 9.7%; pMIH. The use of penicillin due to adenoid infections in the first 5 years was associated with a higher prevalence of MIH (41.7% vs. 19.6%). The prevalence of MIH (11.7%) supports the data previously published from Bosnia-Herzegovina. Girls had higher prevalence of MIH than boys; first molars and incisors in the maxilla were almost twice as often affected as in the mandible. Use of penicillin in the first 5 years was associated with a higher prevalence.

Developmental constraints revealed by co-variation within and among molar rows in two murine rodents.

Science.gov (United States)

Renaud, Sabrina; Pantalacci, Sophie; Quéré, Jean-Pierre; Laudet, Vincent; Auffray, Jean-Christophe

2009-01-01

Morphological integration corresponds to interdependency between characters that can arise from several causes. Proximal causes of integration include that different phenotypic features may share common genetic sets and/or interact during their development. Ultimate causes may be the prolonged effect of selection favoring integration of functionally interacting characters, achieved by the molding of these proximal causes. Strong and direct interactions among successive teeth of a molar row are predicted by genetic and developmental evidences. Functional constraints related to occlusion, however, should have selected more strongly for a morphological integration of occluding teeth and a corresponding evolution of the underlying developmental and genetic pathways. To investigate how these predictions match the patterns of phenotypic integration, we studied the co-variation among the six molars of the murine molar row, focusing on two populations of house mice (Mus musculus domesticus) and wood mice (Apodemus sylvaticus). The size and shape of the three upper and lower molars were quantified and compared. Our results evidenced similar patterns in both species, size being more integrated than shape among all the teeth, and both size and shape co-varying strongly between adjacent teeth, but also between occluding teeth. Strong co-variation within each molar row is in agreement with developmental models showing a cascade influence of the first molar on the subsequent molars. In contrast, the strong co-variation between molars of the occluding tooth rows confirms that functional constraints molded patterns of integration and probably the underlying developmental pathways despite the low level of direct developmental interactions occurring among molar rows. These patterns of co-variation are furthermore conserved between the house mouse and the wood mouse that diverged >10 Ma, suggesting that they may constitute long-running constraints to the diversification of the murine

Perception of molar-incisor hypomineralisation (MIH) by Iraqi dental academics.

Science.gov (United States)

Ghanim, Aghareed; Morgan, Michael; Mariño, Rodrigo; Manton, David; Bailey, Denise

2011-07-01

The understanding and detection of molar-incisor hypomineralisation (MIH) is linked to its recognition by clinicians. No study has investigated dental clinicians' level of perception regarding MIH in the Middle East region including Iraq. To determine the perception of Iraqi academic clinicians about MIH prevalence, severity and aetiological factors. A questionnaire, based on previous European and Australian/New Zealand studies was administered to the academic dental staff of Mosul University. A response rate of 77.7% was reported. General dental practitioners represented 30.8% of the total respondents, whilst 65.1% were dentists with post-graduate qualification. The majority of the respondents (81.2%) encountered MIH in their clinical activities and 37.3% of them identified that the prevalence appeared to have increased in recent years. Fewer than half of the respondents observed MIH affected teeth on a monthly basis. The condition was less commonly seen in primary second molars than the first permanent molars. A variation in views was recorded about MIH specific aetiological factor/s. Respondents advocated the need for clinical training regarding MIH-aetiological and therapeutic fields. Molar-incisor hypomineralisation is a condition commonly diagnosed by Iraqi dental academics. No apparent consensus existed between the general and specialist dentists regarding the anticipated prevalence, severity and aetiology of this condition. © 2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

Partial molar volumes of hydrogen and deuterium in niobium, vanadium, and tantalum

International Nuclear Information System (INIS)

Peterson, D.T.; Herro, H.M.

1983-01-01

The partial molar volumes of hydrogen and deuterium were measured in vanadium, niobium, and tantalum by a differential pressure technique. One-half of an electrolytically charged sample plat was compressed between hardened steel blocks in a hydraulic press. The activity of hydrogen in the hig pressure region was raised and caused hydrogen to diffuse into the low pressure region. The partia molar volume was calculated from the ratio of the hydrogen concentrations in the high and low pressure regions of the sample. Small isotope effects were found in the partial molar volume. Hydrogen had the larger volume in niobium and tantalum, but the reverse was true in vanadium

A New Orthodontic Appliance with a Mini Screw for Upper Molar Distalization

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Nurhat Ozkalayci

2016-01-01

Full Text Available The aim of this study is to present a new upper molar distalization appliance called Cise distalizer designed as intraoral device supported with orthodontic mini screw for upper permanent molar distalization. The new appliance consists of eight main components. In order to understand the optimum force level, the appliance under static loading is tested by using strain gage measurement techniques. Results show that one of the open coils produces approximately 300 gr distalization force. Cise distalizer can provide totally 600 gr distalization force. This range of force level is enough for distalization of upper first and second molar teeth.

Eficacia del uso del plasma rico en factores de crecimiento en defectos periodontales distales de segundos molares inferiores, posterior a la extracción de un tercer molar mandibular

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Carlos Sánchez-Gutiérrez

2017-07-01

Conclusiones: No se encontró diferencia significativa con el uso de PRFC en cuanto a ganancia en el nivel clínico de inserción periodontal en el área distal de segundos molares después de la extracción de terceros molares inferiores retenidos.

IMRT delivers lower radiation doses to dental structures than 3DRT in head and neck cancer patients.

Science.gov (United States)

Fregnani, Eduardo Rodrigues; Parahyba, Cláudia Joffily; Morais-Faria, Karina; Fonseca, Felipe Paiva; Ramos, Pedro Augusto Mendes; de Moraes, Fábio Yone; da Conceição Vasconcelos, Karina Gondim Moutinho; Menegussi, Gisela; Santos-Silva, Alan Roger; Brandão, Thais B

2016-09-07

Radiotherapy (RT) is frequently used in the treatment of head and neck cancer, but different side-effects are frequently reported, including a higher frequency of radiation-related caries, what may be consequence of direct radiation to dental tissue. The intensity-modulated radiotherapy (IMRT) was developed to improve tumor control and decrease patient's morbidity by delivering radiation beams only to tumor shapes and sparing normal tissue. However, teeth are usually not included in IMRT plannings and the real efficacy of IMRT in the dental context has not been addressed. Therefore, the aim of this study is to assess whether IMRT delivers lower radiation doses to dental structures than conformal 3D radiotherapy (3DRT). Radiation dose delivery to dental structures of 80 patients treated for head and neck cancers (oral cavity, tongue, nasopharynx and oropharynx) with IMRT (40 patients) and 3DRT (40 patients) were assessed by individually contouring tooth crowns on patients' treatment plans. Clinicopathological data were retrieved from patients' medical files. The average dose of radiation to teeth delivered by IMRT was significantly lower than with 3DRT (p = 0.007); however, only patients affected by nasopharynx and oral cavity cancers demonstrated significantly lower doses with IMRT (p = 0.012 and p = 0.011, respectively). Molars received more radiation with both 3DRT and IMRT, but the latter delivered significantly lower radiation in this group of teeth (p dental groups. Maxillary teeth received lower doses than mandibular teeth, but only IMRT delivered significantly lower doses (p = 0.011 and p = 0.003). Ipsilateral teeth received higher doses than contralateral teeth with both techniques and IMRT delivered significantly lower radiation than 3DRT for contralateral dental structures (p radiation doses to teeth than 3DRT, but only for some groups of patients and teeth, suggesting that this decrease was more likely due to the protection of

Lower first permanent molars: developing better predictors of spontaneous space closure.

Science.gov (United States)

Teo, Terry Kuo-Yih; Ashley, Paul Francis; Derrick, Donald

2016-02-01

First, first permanent molars (FPMs) of poor prognosis are often planned for extraction at an 'ideal time' so that second permanent molars (SPMs) erupt favourably to replace them. However for lower FPM extractions, timing is not an accurate predictor of success. The aim of this study was to identify additional radiographic factors that could better predict the degree of spontaneous space closure of the lower SPM following FPM extraction. Data from a previous study of 127 lower SPMs from 66 patients was re-analysed by incorporating additional radiographic factors. These included calcification stage of the bifurcation of the SPM, position of the second premolar, mesial angulation of SPM in relation to the FPM, and presence of the third permanent molar. Results were analysed using ordered logistic regression. Only 58 per cent of FPMs extracted at the 'ideal time' (SPM development at Demirjian stage E) had complete space closure. The best outcomes resulted from a combination of SPMs not at Demirjian development stage G, together with the presence of mesial angulation of the SPM and presence of the third permanent molar, where 85 per cent of those cases had complete space closure. Apart from extraction timing of the FPM, consideration must also be given to the presence of the third permanent molar and angulation of the SPM in order to ensure a reliable degree of spontaneous space closure of the lower SPM. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Cone beam computed tomography radiation dose and image quality assessments.

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Lofthag-Hansen, Sara

2010-01-01

examinations of impacted lower third molars and retained upper cuspids. It varied between 11-77 microSv. Radiation dose should be evaluated together with image quality. Images of a skull phantom were obtained with both units varying tube voltage, tube current, degree of rotation and FOVs. Seven observers assessed subjective image quality using a six-point rating scale for two diagnostic tasks: periapical diagnosis and implant planning in the posterior part of the jaws. Intra-observer agreement was good and inter-observer agreement moderate. Periapical diagnosis was found to, regardless of jaw, require higher exposure parameters compared to implant planning. Implant planning in the lower jaw required higher exposure parameters compared to upper jaw. Substantial dose reduction could be made without loss of diagnostic information by using a rotation of 180 degrees, in particular implant planning in upper jaw. CBCT with small FOVs was found to be well-suited for periapical diagnosis and implant planning. The CTDI method is not applicable estimating effective dose for these units. Based on DAP values effective dose varied between 11-77 microSv (ICRP 60, 1991) in a retrospectively selected patient material. Adaptation of exposure parameters to diagnostic task can give substantial dose reduction.

Digital image processing of periapical radiographs with low dose of radiation

International Nuclear Information System (INIS)

Kerbauy, Warley David; Moraes, Luiz Cesar de

1996-01-01

The aim of the study was to evaluate whether digitized images obtained from peri apical radiographs taken with low dose of radiation could be improved with the aid of a computer software (Photo Styler) for digital treatment. Serial and standardized radiographs of molar and pre molar areas were studied. A total of 57 images equivalent to the radiographs taken with reduced exposure time (60 and 80% of the time considered normal), digitized and treated, were submitted to the evaluation of seven examiners which compared them with those images without treatment. It was verified that about 80% of the images equivalent to the radiographs taken with 60% reduction of ordinary exposure time were considered to having quality for supporting diagnosis. As for the images taken with 80% reduction of ordinary exposure time, about 50% of them were considered suitable for the same purpose. (author)

Possible effects of insulin-like growth factor-I, IGF-binding protein-3 and IGF-1/IGFBP-3 molar ratio on mammographic density: a cross-sectional study.

Science.gov (United States)

Meggiorini, M L; Cipolla, V; Borgoni, G; Nofroni, I; Pala, A; de Felice, C

2012-01-01

The purpose of this study was to examine the possible effects of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio on mammographic density and assess whether this relationship was similar in subgroups of pre- and postmenopausal women. A group of 341 Italian women of childbearing age or naturally postmenopausal who had performed mammographic examination at the section of radiology of our department a maximum three months prior to recruitment were enrolled. A blood sample was drawn for determination of IGF-1, IGFBP-3 levels and IGF-1/IGFBP-3 molar ratio was calculated. On the basis of recent mammograms the women were divided into two groups: dense breast (DB) and non-dense breast (NDB). To assess the association between mammographic density and IGF-1, IGFBP-3 and Molar ratio Student's t-test was employed before and after stratified by menopausal status. The analysis of the relationship between mammographic density and plasma levels of IGF-1, IGFBP-3 and IGF-1/IGFBP-3 molar ratio showed that IGF-1 levels and molar ratio varied in the two groups resulting in higher mean values in the DB group whereas IGFBP-3 showed similar values in both groups (DB and NDB). After stratification of the study population by menopausal status, no association was found. Our study provides strong evidence of a crude association between breast density, and plasma levels of IGF-1 and molar ratio. IGF-1 and molar ratio might increase mammographic density and thus the risk of developing breast cancer.

Space changes after premature loss of the mandibular primary first molar: a longitudinal study.

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Lin, Y T; Chang, L C

1998-01-01

The purpose of this study was to evaluate the space changes after premature loss of the primary mandibular first molar. Twenty-one children (12 boys and 9 girls), with premature loss of the primary mandibular first molar, were selected from the children's dental clinic for this study. The age ranged from 5.1 to 7.2 years with an average of 6 years and 11 months. Mandibular study casts were made from alginate impression for each initial examination and a follow-up examination eight months later. Four measurements including D+E (first and second primary molars) space, arch width, arch length and arch perimeter were tested for comparisons between the initial examination and the follow-up examination eight months later. The D+E space of intact primary molars served as a control. The results showed that the D+E space on the extraction side after the follow-up examination eight months later was significantly shorter than the control side (p = 0.025) and less than the initial D+E space (p 0.05). It is concluded that the space change after the eruption of the first permanent molar in the mandible is mostly distal movement of the primary cuspid during the early stage of premature loss of the primary first molar.

Effect of Cu/In molar ratio on the microstructural and optical properties of microcrystalline CuInS2 prepared by solvothermal route

International Nuclear Information System (INIS)

Das, Kajari; Panda, Subhendu K.; Gorai, Soma; Mishra, Pratima; Chaudhuri, Subhadra

2008-01-01

Synthesis and characterization of CuInS 2 powder sample prepared by a simple and convenient solvothermal method is reported. The influence of the variation of Cu/In molar ratio from 0.69 to 1.25 on the particle morphology, crystal structure and optical properties of CuInS 2 samples was studied. The X-ray diffraction studies indicated that the samples were polycrystalline in nature. SEM images of the samples revealed that the copper-rich products were uniform microspheres with smooth surfaces, whereas microspheres formed by network of interconnected flakes were obtained for indium-rich products. The optical band gaps (E g ) of the products decreased from 1.60 to 1.43 eV with variation of Cu/In molar ratio. The variation of the Urbach tail width with Cu/In molar ratio indicated that the density of the defects is much higher for the indium-rich CuInS 2 , which was clearly revealed from Raman measurements

Onset of molar incisor hypomineralization (MIH).

Science.gov (United States)

Fagrell, Tobias G; Salmon, Phil; Melin, Lisa; Norén, Jörgen G

2013-01-01

The etiological factors and timing of the onset of molar incisor hypomineralization (MIH) are still not clear. The aim of this study was to examine ground radial and sagittal sections from teeth diagnosed with MIH using light microscopy, polarized light microscopy and X-ray micro-computed tomography (XMCT) and to estimate the onset and timing of the MIH and to relate the hypomineralized enamel to the incremental lines. Thirteen extracted permanent first molars diagnosed MIH, were analyzed with light microscopy and XMCT. The hypomineralized areas were mainly located in the mesio-buccal cusps, starting at the enamel-dentin-junction and continuing towards the enamel surface. In a relative gray scale analysis the values decreased from the EDJ towards the enamel surface. The findings indicate that the ameloblasts in the hypomineralized enamel are capable of forming an enamel of normal thickness, but with a substantial reduction of their capacity for maturation of enamel. Chronologically, it is estimated that the timing of the disturbance is at a period during the first 6-7 months of age.

Exodoncia del tercer molar: Factores que determinan complejidad

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Ivan Manotas Arevalo

2014-06-01

Full Text Available ResumenUno de los procedimientos más frecuentes en el campo de la Cirugía Oral es la exodoncia, o extracción dental. La prevención y la promoción de hábitos saludables dentro de los que se cuenta la práctica del cepillado dental, uso de dentífricos, hilo dental y enjuagatorios bucales, además de visitas periódicas de control a especialistas y odontólogos generales e higienistas bucales ha conllevado a una reducción en la perdida de estructuras dentarias por causa de la caries y las periodontopatìas. Sin embargo se mantiene alto el número de exodoncias indicadas por falta de espacio en la estructura de los maxilares para la erupción dental, así como alteraciones en la posición y angulacion de los órganos dentales sobre su eje que impide una adecuada ubicación logrando que se indique su extracción. Dentro de la serie dental los órganos dentarios más frecuentemente afectados por este tipo de alteraciones son los terceros molares. También se mencionan que son esos mismos dientes los que acusan mayor grado de complejidad para realizar el procedimiento de exodoncia, y los que causan mayor grado de morbilidad posquirúrgica en el paciente, con un número mayor de complicaciones y su severidad, descritas en la literatura. (Duazary 2008; 141-147. Este artículo pretende analizar los factores que determinan complejidad en la exodoncia del tercer molar a partir de una revisión bibliografía y comparación de ésta.AbstractOne of the most frequent procedure used in the field of Oral Surgery is extracted, or tooth extraction. The prevention and promoting healthy habits in mind that the practice of brushing teeth, use of toothpastes, mouthwashes and dental floss mouth, in addition to regular monitoring visits to specialists and general dentists and oral hygiene has led to a reduction in the loss of structures caused by tooth decay and periodontal pathology. However remains high number of extractions indicated by lack of space in the

Experimental standard molar enthalpies of formation of some 4-alkoxybenzoic acids

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Lobo Ferreira, Ana I.M.C.; Maciel, Fabrice M.

2010-01-01

The present work is part of a research program on the energetics of the linear 4-n-alkoxybenzoic acids, aiming the study of the enthalpic effect of the introduction of an alkoxy chain in the position 4- of the benzoic acid ring. In this work, we present the results of the thermochemical research on 4-n-alkoxybenzoic acids with the alkoxy chain length n = 2, 4, and 8. The standard (p 0 =0.1MPa) molar enthalpy of formation of crystalline 4-ethoxybenzoic acid, 4-butoxybenzoic acid, and 4-(octyloxy)benzoic acid was measured, at T = 298.15 K, by static-bomb calorimetry. These values, combined with the values of standard molar enthalpies of sublimation, were used to derive the standard molar enthalpies of formation in the gaseous phase.

Molar-incisor hypomineralization (MIH) in a group of school-aged children in Benghazi, Libya.

Science.gov (United States)

Fteita, D; Ali, A; Alaluusua, S

2006-06-01

Molar-incisor hypomineralization (MIH) is common in many countries and it has significant impact on treatment need. The aim of the present study was to assess developmental enamel defects with an emphasis to MIH in children from four primary schools in Benghazi, Libya. Permanent first molars of a total of 378 (188 females) 7.0-8.9-year-old children were examined for demarcated opacities, diffuse opacities and hypoplasia in their schools using a portable light, a mirror, and a probe. A subgroup of children attending two of the four schools and having all incisors and first molars erupted (N = 154) was examined for enamel defects in these teeth. Eleven children (2.9%) had MIH. The mean value of demarcated opacities in their first molars was 1.5. MIH lesions were found only in 1.1% of the children's first molars (tooth prevalence) and all lesions were mild. Six children (1.6%) had diffuse opacities and 3 (0.8%) had hypoplastic defects in their first molars. Fourteen out of 154 children (9%) who had both incisors and molars examined had some kind of developmental enamel defect: 11 children (7.1%) had demarcated opacities, 3 (1.9%) had diffuse opacities, and none had hypoplasia. MIH was rare in Benghazi, Libya. The prevalence was clearly lower than in comparable studies performed in Italy or in Nordic countries, where, according to the earlier reports, MIH is seen in every fifth or sixth child. Our result may be valuable when so far mostly unknown etiology behind MIH is investigated.

Ectopic eruption of the maxillary first permanent molar: characteristics and occurrence in growing children.

Science.gov (United States)

Barberia-Leache, Elena; Suarez-Clúa, María Cruz; Saavedra-Ontiveros, Dolores

2005-07-01

The purpose of this study was to determine the characteristics and occurrence of the ectopic eruption of the maxillary first permanent molar in a sample of growing Spanish children. A descriptive, observational, retrospective study was done using the radiographs of 509 consecutive patients, who were in the first phase of mixed dentition. A method was designed to evaluate the amount of pathologic resorption of the second maxillary primary molar and the impaction of the first permanent molar measured in millimeters. Statistical analysis of the studied variables was done using chi-square, analysis of variance, and Pearson correlation coefficient. The frequency of occurrence was 4.3% with no differences in both sexes. Of these, 36.4% were unilateral and 63.6% bilateral with a right:left relation of 3:1. Of the 36 ectopic molars, 69.4% self-corrected spontaneously. In such cases, the pathological resorption of the root of the second maxillary primary molar and its adverse clinical implications were persistent. The relation between self-correction and impaction was 2.27:1. The average impaction on the right side was 2.91 mm and 1.6 mm on the left side. Correlation between the magnitude of resorption and grade of impaction was not observed. Although resorption was found on grades I and II, spontaneous self-correction could occur without arch length loss. However, on grade III or more, therapeutic intervention has to be done. The benefit of early diagnosis and treatment of the maxillary first permanent molar is the prevention of the premature loss of second maxillary deciduous molar and the resulting malocclusion.

Excess molar volumes and isentropic compressibilities of binary ...

Indian Academy of Sciences (India)

Excess molar volume; binary liquid mixtures; isentropic compressibility; intermolecular interactions. ... mixtures are essential for fluid flow, mass flow and heat transfer processes in chemical ... Experimentally determined values of density(ρ).

Radiological age estimation: based on third molar mineralization and eruption in Turkish children and young adults.

Science.gov (United States)

Karadayi, Beytullah; Kaya, Ahsen; Kolusayın, Melek Ozlem; Karadayi, Sükriye; Afsin, Hüseyin; Ozaslan, Abdi

2012-11-01

Radiographic evaluation of mineralization and eruption stages of third molars using dental panoramic radiographies can be an efficient tool for chronological age estimation in both forensic sciences and legal medicine. The third molar tooth is utilized for dental age estimation about the age span of 15-23 years because it represents the only tooth still in development. The aim of this study is to obtain and analyze data regarding third molar development and eruption in Turkish population for dental age estimation. A total of 744 dental panoramic radiographies of 394 female and 350 male subjects aged between 8 and 22 years were examined. Third molar development was determined according to the Nolla classification system, and eruption was assessed relative to the alveolar bone level. Mandibular and maxillary third molars were generally found at similar stages of development on both sides. Nolla stage 6 (completed crown calcification) was reached at around the age of 15 in both maxillary and mandibular third molars in both sexes. Alveolar emergence was at around the age of 16 in males and around age of 17 in females. Although third molars' eruption shows greater variability than development of third molars, data which were obtained from this study about eruption of these teeth can be supportive to development data for age estimation.

PERBEDAAN TOPICAL FLUORIDE APPLICATION DAN FISSURE SEALANT DALAM MENCEGAH KARIES PADAGIGI MOLAR SATU

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Pawarti Pawarti

2017-07-01

Full Text Available Abstract: Topical Fluoride Application And Fissure Sealant To Prevent Dental Caries Permanent First Molars. Anatomy pits and fissures of teeth are caries initiation vulnerable areas of the permanent molars that grow at the age of 6 years where children can not perform oral hygiene. Caries prevention can be done by closing the pits and fissures or application of fluoride (topical fluoride application on the surface of the teeth. The purpose of this study was to analyze the difference fissure sealants and topical application of fluoride to prevent dental caries of first permanent molars. This study was a quasi-experimental study with time series, a sample was taken by purposive 117-second grade students of SDN District of North Pontianak. Data were analyzed using t-test. The result showed that fissure sealant more effective in caries prevention of first permanent molar than topical fluoride application where there were none caries teeth after and month fissure sealant, 25% sealant partially off and 11% fully off. Teeth that have done fluoride after 6 months of 3.9% of dental caries, the eighth month of 5.4% of dental caries. There was a significant difference between the effectiveness of fissure sealants with topical application of fluoride to prevent dental caries in first permanent molars p-value < 0.05, after 6-month p-value: 0.004 and after 8-month p-value: 0.001. Abstrak: Topical Fluoride Application Dan Fissure Sealant Untuk Mencegah Karies Pada Gigi Molar Satu Permanen. Anatomi pit dan fisura gigi merupakan daerah rentan inisiasi karies gigi molar satu permanen yang tumbuh pada usia 6 tahun anak belum bisa melakukan kebersihan mulutnya. Pencegahan karies dapat dilakukan dengan cara menutup pit dan fissure atau pengolesan fluor (topical fluoride application pada permukaan gigi. Tujuan penelitian ini untuk menganalisis perbedaan efektivitas fissure sealant dan topical fluoride application untuk mencegah karies gigi molar satu permanen anak

Comparative study of intravenous Tramadol versus Ketorolac for preventing postoperative pain after third molar surgery--a prospective randomized study.

Science.gov (United States)

Gopalraju, Prathibha; Lalitha, Ramanujapuram Manikarnike; Prasad, Kavitha; Ranganath, Krishnappa

2014-07-01

The aim of this comparative, prospective, randomized, controlled study was to evaluate two different regimens of analgesics: a preoperative intravenous dose of either Tramadol or Ketorolac given 10 min prior to surgery to assess their impact on clinical recovery after third molar surgery. Forty patients requiring surgical extraction of unilateral impacted mandibular third molars similar in position were enrolled in the study. Patients were randomly divided into two groups based on permuting the numbers. Patients in Group 1 and Group 2 were administered either Tramadol 50 mg or Ketorolac 30 mg, intravenously, 10 min prior to surgery. The difference in postoperative pain was assessed by four primary points: pain intensity as measured by a 10 mm visual analogue scale hourly for 12 h, median time to rescue analgesics, number of analgesics consumed and patient's overall 5-point global assessment scale. Throughout the 12 h investigation period, patients treated with Ketorolac reported significantly lower pain intensity scores, significantly longer time to rescue analgesics (Acetaminophen 500 mg) and less intake of postoperative analgesics. In Group 2, 40% of the patient had good overall assessment as compared to Group 1 where only 25% of patients had good overall assessment. The current study shows that pre-emptive use of Inj. Ketorolac 30 mg intravenously can reduce the severity of the postoperative sequelae of asymptomatic impacted mandibular third molar surgery. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Co-production of acetone and ethanol with molar ratio control enables production of improved gasoline or jet fuel blends.

Science.gov (United States)

Baer, Zachary C; Bormann, Sebastian; Sreekumar, Sanil; Grippo, Adam; Toste, F Dean; Blanch, Harvey W; Clark, Douglas S

2016-10-01

The fermentation of simple sugars to ethanol has been the most successful biofuel process to displace fossil fuel consumption worldwide thus far. However, the physical properties of ethanol and automotive components limit its application in most cases to 10-15 vol% blends with conventional gasoline. Fermentative co-production of ethanol and acetone coupled with a catalytic alkylation reaction could enable the production of gasoline blendstocks enriched in higher-chain oxygenates. Here we demonstrate a synthetic pathway for the production of acetone through the mevalonate precursor hydroxymethylglutaryl-CoA. Expression of this pathway in various strains of Escherichia coli resulted in the co-production of acetone and ethanol. Metabolic engineering and control of the environmental conditions for microbial growth resulted in controllable acetone and ethanol production with ethanol:acetone molar ratios ranging from 0.7:1 to 10.0:1. Specifically, use of gluconic acid as a substrate increased production of acetone and balanced the redox state of the system, predictively reducing the molar ethanol:acetone ratio. Increases in ethanol production and the molar ethanol:acetone ratio were achieved by co-expression of the aldehyde/alcohol dehydrogenase (AdhE) from E. coli MG1655 and by co-expression of pyruvate decarboxylase (Pdc) and alcohol dehydrogenase (AdhB) from Z. mobilis. Controlling the fermentation aeration rate and pH in a bioreactor raised the acetone titer to 5.1 g L(-1) , similar to that obtained with wild-type Clostridium acetobutylicum. Optimizing the metabolic pathway, the selection of host strain, and the physiological conditions employed for host growth together improved acetone titers over 35-fold (0.14-5.1 g/L). Finally, chemical catalysis was used to upgrade the co-produced ethanol and acetone at both low and high molar ratios to higher-chain oxygenates for gasoline and jet fuel applications. Biotechnol. Bioeng. 2016;113: 2079-2087. © 2016 Wiley

Unusual Root Canal Morphology of the Maxillary Second Molar: A Case Report

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Neslihan Şımşek

2013-01-01

Full Text Available Introduction. This clinical case report presents the successful endodontic treatment of a maxillary second molar that has a mandibular molar-like anatomy with no palatal root and with each of its roots containing two separate root canals. Cone-beam computed tomography (CBCT was used to confirm this unusual anatomy. Methods. A 34-year-old male patient was referred to the Department of Endodontics at Inonu University’s Faculty of Dentistry because of severe pain in his right maxillary second molar. Clinical and radiographic examinations identified unusual roots and root canals anatomy, and CBCT was planned in order to understand the nature of these variations. Cleaning and shaping procedures were performed using the crown down technique with Sybron Endo (Glendora, CA, USA rotary instruments, and endodontic treatment was completed with gutta-percha cones and AH Plus resin sealers using the cold lateral compaction technique. Conclusions. The maxillary second molar exhibits aberrations and variations in terms of the numbers and configurations of its roots and root canals, and CBCT can be a useful imaging technique in endodontics.

Prevalence and morphometric analysis of three-rooted mandibular first molars in a Brazilian subpopulation

OpenAIRE

Rodrigues, Clarissa Teles; de Oliveira-Santos, Christiano; Bernardineli, Norberti; Duarte, Marco Antonio Hungaro; Bramante, Clovis Monteiro; Minotti-Bonfante, Paloma Gagliardi; Ordinola-Zapata, Ronald

2016-01-01

ABSTRACT The knowledge of the internal anatomy of three-rooted mandibular molars may help clinicians to diagnose and plan the root canal treatment in order to provide adequate therapy when this variation is present. Objectives: To determine the prevalence of three-rooted mandibular molars in a Brazilian population using cone beam computed tomography (CBCT) and to analyze the anatomy of mandibular first molars with three roots through micro-CT. Material and Methods: CBCT images of 116 patien...

Prevalence of missing and impacted third molars in adults aged 25 years and above

OpenAIRE

Jung, Yun-Hoa; Cho, Bong-Hae

2013-01-01

Purpose The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent ...

Modified Distal Shoe Appliance for Premature Loss of Multiple Deciduous Molars: A Case Report

OpenAIRE

Bhat, Prasanna Kumar; K., Navin H.; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

2014-01-01

Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist’s armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first...

Computed tomographic anatomy of the mandibular first and second molars and their surrounding structures in the spread of odontogenic infection

International Nuclear Information System (INIS)

Ohshima, Aya; Ariji, Yoshiko; Gotoh, Masakazu; Izumi, Masahiro; Naitoh, Munetaka; Kurita, Kenichi; Shimozato, Kazuo; Ariji, Eiichiro

2009-01-01

The purposes of this study were to analyze the CT anatomy of the mandibular first and second molars in uninfected subjects and to clarify the pathway of odontogenic infection originating from the mandibular first and second molars. CT anatomies, especially for bucco-lingual aspects and the surrounding soft tissues, were investigated in 100 uninfected subjects and 17 infected patients. At the level of bifurcation, disappearance of the cortical plates was frequently observed on the buccal and lingual sides of the first molars, and it was reduced on the buccal side in the second molar. In the first molar, the bony width was thinner on the buccal than the lingual side. The lingual cortices were thinner in the second molar. All medial pterygoid and 88% of masseter muscles were situated posteriorly, without horizontally overlapping the second molar, whereas the mylohyoid muscle (MhM) overlapped horizontally with the first and second molars. The MhM was positioned superior to the root apices in 10 and 39% of first and second molars, respectively. All patients with first molar infection showed involvement of buccal structures, and one showed lingual side involvement. In contrast, six of nine patients with second molar infection showed involvement on the lingual side. Infection originating from the second molar was more likely to spread to the lingual side than infection originating from the first molar. CT anatomy surrounding the causal teeth supported the spread pathways of mandibular first and second molar infection. (author)

Prevention of Localized Osteitis in Mandibular Third-Molar Sites Using Platelet-Rich Fibrin

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Donald R. Hoaglin

2013-01-01

Full Text Available Purpose. To review our experience utilizing platelet rich fibrin (PRF, which is reported to aid in wound healing of extraction sites, for the prevention of localized osteitis following lower third-molar removal. Materials and Methods. PRF was placed in the mandibular third-molar extraction sites, 200 sites total, on 100 consecutive patients treated in our practice, by the authors. The patients were managed with standard surgical techniques, intraoperative IV antibiotic/steroid coverage, and routine postoperative narcotic analgesics/short-term steroid coverage. All patients were reevaluated for localized osteitis within 7–10 days of the surgery. A comparison group consisted of 100 consecutive patients who underwent bilateral removal of indicated mandibular wisdom teeth and did not receive PRF placement within the lower third molar surgical sites. Results. The incidence of localized osteitis (LO following removal of 200 lower third molars with simultaneous PRF placement within the extraction site was 1% (2 sites out of 200. The group of patients whose mandibular 3rd molar sockets were not treated with PRF demonstrated a 9.5% (19 sites out of 200 incidence of localized osteitis. The latter group also required 6.5 hours of additional clinical time to manage LO than the study group who received PRF. Conclusions. This retrospective review demonstrated that preventative treatment of localized osteitis can be accomplished using a low cost, autogenous, soluble, biologic material, PRF, that PRF enhanced third-molar socket healing/clot retention and greatly decreased the clinical time required for postoperative management of LO.

Evaluation of autogenous tooth transplantation for replacement of the missing or unrestorable mandibular molar tooth

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Wahiduj Jaman

2017-06-01

Full Text Available This study was undertaken to evaluate the functional and occlusal stability of autogenous tooth transplantation. A total of 30 patients were included. Among them, 21 participants received transplanted first molar and the remaining 9 received transplanted second molar. In all the cases, donor tooth were third molar. In each participant, extraction of un-restorable first or second molar tooth was performed which was then replaced by atrumatic extracted third molar tooth. Each third molar tooth was placed in the recipient extracted socket, followed by the evaluation of the occlusion and then stabilized with arch bar and ligature wire. Clinical follow-up evaluation was performed at 15 days, 3 and 12 months in respect to occlusal stability, tooth mobility and periodontal status. It was found that 23 transplanted tooth were successful and the remaining 7 tooth need long-term observation for the final outcome, which was statistically significant. It can be concluded that the autogenous tooth transplantation can replace missing tooth to ensure the preservation of function, aesthetic and to prevent bone resorption of the missing area of the jaw, which can lead to exceptional esthetic and functional outcome.

Functional approach to a Class II patient with upper first molar impaction

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Giacomo D′Orlandi

2014-01-01

Full Text Available The lack of the left first molar maxillary and the left second molar maxillary, caused respectively by impaction and agenesis is a very rare case, which determines an important occlusal imbalance and asymmetrical mandible movement. A gnatologic and functional orthodontic approach were planned to improve the retrognathic mandible and the muscular activity using kinesiograph and electromyography.

Partial Molar Volumes of Aqua Ions from First Principles.

Science.gov (United States)

Wiktor, Julia; Bruneval, Fabien; Pasquarello, Alfredo

2017-08-08

Partial molar volumes of ions in water solution are calculated through pressures obtained from ab initio molecular dynamics simulations. The correct definition of pressure in charged systems subject to periodic boundary conditions requires access to the variation of the electrostatic potential upon a change of volume. We develop a scheme for calculating such a variation in liquid systems by setting up an interface between regions of different density. This also allows us to determine the absolute deformation potentials for the band edges of liquid water. With the properly defined pressures, we obtain partial molar volumes of a series of aqua ions in very good agreement with experimental values.

Radiographic prognostic factors determining spontaneous space closure after loss of the permanent first molar.

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Patel, Sameer; Ashley, Paul; Noar, Joseph

2017-04-01

Permanent first molars (PFM) with a poor prognosis are routinely extracted in children throughout the United Kingdom. National guidelines suggest that to achieve spontaneous closure for the mandibular arch, the PFM should be extracted at 8 to 10 years of age, during bifurcation formation of the second molar. The literature is of limited quality and has suggested alternative variables that may be associated with successful space closure. Our aim was to investigate the radiographic prognostic factors associated with space closure after extraction of PFM. Two objectives of the research are reported in this article: to determine factors that might predict space closure of the second molar after extraction of the PFM, and to develop a tool kit to aid clinical decision making. We assessed 148 maxillary and 153 mandibular PFM extracted from 81 participants retrospectively. Dental age, second molar developmental stage, second premolar and second molar angulations, and presence or absence of the third molar were assessed on the preextraction orthopantomograms. Outcome was assessed via visual examination, study models, or radiographs. Closure occurred in 89.9% of the maxillary and 49.0% of the mandibular quadrants. Dental age was statistically, but not clinically, significant in the maxillary arch (P space closure. The developed tool kit requires further validity testing. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

The unfolding effects on the protein hydration shell and partial molar volume: a computational study.

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Del Galdo, Sara; Amadei, Andrea

2016-10-12

In this paper we apply the computational analysis recently proposed by our group to characterize the solvation properties of a native protein in aqueous solution, and to four model aqueous solutions of globular proteins in their unfolded states thus characterizing the protein unfolded state hydration shell and quantitatively evaluating the protein unfolded state partial molar volumes. Moreover, by using both the native and unfolded protein partial molar volumes, we obtain the corresponding variations (unfolding partial molar volumes) to be compared with the available experimental estimates. We also reconstruct the temperature and pressure dependence of the unfolding partial molar volume of Myoglobin dissecting the structural and hydration effects involved in the process.

Piezosurgery versus Rotatory Osteotomy in Mandibular Impacted Third Molar Extraction

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Bhati, Bharat; Kukreja, Pankaj; Kumar, Sanjeev; Rathi, Vidhi C.; Singh, Kanika; Bansal, Shipra

2017-01-01

Aim: The aim of this study is to compare piezoelectric surgery versus rotatory osteotomy technique in removal of mandibular impacted third molar. Materials and Methods: Sample size of 30 patients 18 males, 12 females with a mean age of 27.43 ± 5.27. Bilateral extractions were required in all patients. All the patients were randomly allocated to two groups in one group, namely control group, surgical extraction of mandibular third molar was done using conventional rotatory osteotomy and in the other group, namely test group, extraction of lower third molar was done using Piezotome. Results: Parameters assessed in this study were – mouth opening (interincisal opening), pain (visual analog scale VAS score), swelling, incidence of dry socket, paresthesia and duration of surgery in both groups at baseline, 1st, 3rd, and 7th postoperative day. Comparing both groups pain scores with (P piezosurgery group (51.40 ± 17.9) minutes compared to the conventional rotatory group with a mean of (37.33 ± 15.5) minutes showing a statistically significant difference (P = 0.002). Conclusion: The main advantages of piezosurgery include soft tissue protection, optimal visibility in the surgical field, decreased blood loss, less vibration and noise, increased comfort for the patient, and protection of tooth structures. Therefore, the piezoelectric device was efficient in decreasing the short-term outcomes of pain and swelling although taking longer duration than conventional rotatory technique it significantly reduces the associated postoperative sequelae of third molar surgery. PMID:28713729

Endodontic therapy of a mandibular third molar with 5 canals: a case report.

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Silberman, Adrian; Heilborn, Carlos; Cohenca, Nestor

2009-06-01

Endodontic treatment of third molars often becomes part of comprehensive treatment plans, as it represents a more conservative and less invasive approach than its therapeutic alternatives. The frequency of anatomic variations in mandibular molars, particularly root canal configuration, requires 2 periapical radiographs from different angles. Upon reading and interpretation of the radiographs, the clinician should consider the anatomy and level of difficulty of the endodontic procedure and refer the patient to an endodontist, if deemed necessary. The present article discusses the successful treatment and preservation of a mandibular third molar with 5 root canals, as well as methods for its clinical management.

ANÁLISE MORFOMÉTRICA DA SÉRIE MOLAR INFERIOR EM DIDELFÍDEOS (MAMMALIA)

OpenAIRE

Luíza Zuchetto Magnus

2014-01-01

Os molares tribosfênicos são considerados grandes inovações dos mamíferos e se relacionam com diversas estruturas e variáveis as quais podem explicar a sua adaptação. O objetivo deste estudo foi verificar a importância da relação do tamanho corporal, da forma mandibular e da dieta, sob enfoque filogenético, no conjunto dos quatro molares inferiores dos marsupiais didelfídeos. Análises de morfometria geométrica da forma dos molares inferiores foram realizadas em 261 espécimes, 130 fêmeas e 131...

A mandibular third molar with three mesial roots: a case report.

Science.gov (United States)

Plotino, Gianluca

2008-02-01

Although its most common configuration is 2 roots and 3 root canals, mandibular molars might have many different combinations. A case of unusual root canal morphology is presented to demonstrate anatomic variations in mandibular molars. Endodontic therapy was performed in a mandibular third molar with 3 separate mesial roots. The appearance of the pulp chamber floor revealed 4 separate canal orifices. Radiographically the 4 root canals ended in their own distinct foramen. Many reports deal with 3 orifices or 3 independent canals in the mesial root, but none described 3 mesial canals in 3 separate mesial roots, indicating a rare anatomic configuration. This report points out the importance of looking for additional canals and unusual canal morphology, because knowledge of their existence might occasionally enable clinicians to treat a case successfully that otherwise might have ended in failure.

Partial molar volumes of hydrogen and deuterium in niobium and vanadium

International Nuclear Information System (INIS)

Herro, H.M.

1979-01-01

Lattice dilation studies and direct pressure experiments gave comparable values for the partial molar volumes of hydrogen and deuterium in niobium and vanadium. Small isotope effects in the partial molar volume of hydrogen were measured in both metals by the differential isotope method. Hydrogen had a larger partial molar volume than deuterium in niobium, but the reverse was true in vanadium. The isotope effect measured in niobium can be represented as being due to the larger amplitude of vibration of the hydrogen atom than the deuterium atom in the metal lattice. Since hydrogen has a larger mean displacement from the equilibrium position than does deuterium, the average force hydrogen exerts on the metal atoms is greater than the force deuterium exerts. The isotope effect in vanadium is likely a result of anharmonic effects in the lattice and local vibrational modes

Demirjian's method in the estimation of age: A study on human third molars.