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Tooth Extraction  

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... can be done using just an injection (a local anesthetic) . You may or may not receive drugs to ... For a surgical extraction, you will receive a local anesthetic, and you may also have anesthesia through a ...

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Tooth extraction, bleeding and pain control.  

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Local anaesthesia is used routinely in dental surgery; it is effective in both pain control and--through the vasoconstrictors often contained within it--the reduction of bleeding. The extraction of deciduous teeth under general anaesthesia is often carried out without these local effects. There are no previous studies to investigate the combined effect of local anaesthesia with general anaesthesia on blood loss and pain control. A randomised, controlled clinical trial was carried out with one hundred children aged 3-5 years. Ethical approval and informed consent were obtained. Surface anaesthetic cream (EMLA) was placed on the hand into which the intravenous access was to be placed. One to two ml of blood was taken at the time of induction as a baseline of the patient's level of haematin pigment. Children in the experimental group were given one quarter of a cartridge (0.5 ml) of local anaesthetic containing epinephrine (1:80,000) in each quadrant before tooth extraction; all blood in swabs, suction equipment and disposables was collected and digested with NaOH. The children were observed for 11 minutes post-operatively for any signs of distress. Total blood loss was calculated by comparison of the baseline sample and the shed blood digests. This study showed that using local anaesthesia for dental extractions under general anaesthesia was associated with decreased blood loss (p = 0.001). The second finding--which has not been reported before--was that this use of local anaesthesia was shown to cause distress to this age group of children upon recovery from the general anaesthetic (p <0.0001). The use of local anaesthetic in this situation provided a useful reduction in post-operative bleeding. However, its use was associated with greater post-operative distress. PMID:11697691

Al-Bahlani, S; Sherriff, A; Crawford, P J

2001-10-01

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Complications associated with cheek tooth extraction in the horse.  

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Common indications for cheek tooth extraction in the horse include dental fracture, periodontal disease, severe decay/ caries, mandibular fracture with alveolar/tooth involvement, and periapical abscess. Complications secondary to extraction of cheek teeth are prevalent. Typical complications may include retained root tip(s), collateral damage of neighboring teeth and alveolar bone, mandibular fracture non-union or delayed union, cemental ankylosis, dilacerated root(s), oroantral/oronasal fistula, palatal deviation of cheek teeth, bone sequestration, sinus involvement, alveolar plug failure, and palatine artery laceration. This paper presents a series of cases that had complications following cheek tooth extraction. Anticipation of problematic extractions, recognition of complications, and appropriate treatment will aid the clinician in managing the inevitable cheek tooth extraction complication. PMID:24660307

Earley, Edward T; Rawlinson, Jennifer E; Baratt, Robert M

2013-01-01

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Pain fiber anesthetic reduces brainstem Fos after tooth extraction.  

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We recently demonstrated that pain-sensing neurons in the trigeminal system can be selectively anesthetized by co-application of QX-314 with the TRPV1 receptor agonist, capsaicin (QX cocktail). Here we examined whether this new anesthetic strategy can block the neuronal changes in the brainstem following molar tooth extraction in the rat. Adult male Sprague-Dawley rats received infiltration injection of anesthetic 10 min prior to lower molar tooth extraction. Neuronal activation was determined by immunohistochemistry for the proto-oncogene protein c-Fos in transverse sections of the trigeminal subnucleus caudalis (Sp5C). After tooth extraction, c-Fos-like immunoreactivity (Fos-LI) detected in the dorsomedial region of bilateral Sp5C was highest at 2 hrs (p local anesthetic lidocaine. Pulpal anesthesia by infiltration injection was confirmed by inhibition of the jaw-opening reflex in response to electrical tooth pulp stimulation. Our results suggest that the QX cocktail anesthetic is effective in reducing neuronal activation following tooth extraction. Thus, a selective pain fiber 'nociceptive anesthetic' strategy may provide an effective local anesthetic option for dental patients in the clinic. PMID:24056223

Badral, B; Davies, A J; Kim, Y H; Ahn, J S; Hong, S D; Chung, G; Kim, J S; Oh, S B

2013-11-01

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Effects of various antiseptics on bacteremia following tooth extraction.  

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The effect of local irrigation of the gingival sulcus, which is considered an important source of bacteremia following dental procedures, with three different antiseptic solutions including hydrogen peroxide, chlorhexidine and povidone iodine, on the frequency of bacteremia after tooth extraction was determined, and the efficacies of the three antiseptics were compared. Although all the antiseptic solutions reduced the frequency of bacteremia to various degrees, povidone iodine was the most effective, and seemed to be the best choice since the decrease was statistically significant. Local administration of antiseptic solutions is therefore recommended as an adjuvant to systemic antibiotic prophylaxis. PMID:1588398

Yamalik, M K; Yücetas, S; Abbaso?lu, U

1992-03-01

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Tooth extraction by orthodontic force after radiation therapy: report of case  

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This report presents a therapeutic approach to orthodontic tooth extraction in a patient at high risk for the development of osteoradionecrosis with conventional techniques. The rationale for this procedure is discussed in detail, combining principles of radiation biology, clinical radiation therapy, and biomechanics of tooth movement.

Rodu, B.; Filler, S.J.; Woodfin, G.K.

1985-12-01

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Tooth extraction by orthodontic force after radiation therapy: report of case  

International Nuclear Information System (INIS)

This report presents a therapeutic approach to orthodontic tooth extraction in a patient at high risk for the development of osteoradionecrosis with conventional techniques. The rationale for this procedure is discussed in detail, combining principles of radiation biology, clinical radiation therapy, and biomechanics of tooth movement

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Unexpected atrial fibrillation during tooth extraction in a sedated elderly patient.  

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A case is reported of unexpected atrial fibrillation in response to tooth extraction under intravenous sedation in a 70-yr-old patient with thoracic aneurysm of the aorta. Atrial fibrillation developed after the additional injection of a 2% solution of lidocaine containing 1:200,000 epinephrine. After 20 min, the arrhythmia disappeared spontaneously. The arrhythmia was associated with insufficient analgesia for tooth extraction, epinephrine in the local anesthetic, decreased blood pressure, a...

Umino, M.; Ohwatari, T.; Shimoyama, K.; Nagao, M.

1994-01-01

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Mesenchymal stem/progenitor cell isolation from tooth extraction sockets.  

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Bone marrow-derived mesenchymal stem/progenitor cells (BMSCs) are commonly used in regeneration therapy. The current primary source of BMSCs is the iliac crest; however, the procedure is associated with various burdens on the patient, including the risk of pain and infection. Hence, the possibility to collect BMSCs from other, more accessible, sources would be an attractive approach. It is well known that stem cells migrate from surrounding tissues and play important roles in wound healing. We thus hypothesized that stem/progenitor cells could be isolated from granulation tissue in the dental socket, and we subsequently collected granulation tissue from dog dental socket 3 d after tooth extraction. After enzyme digestion of the collected tissue, the cells forming colonies constituted the dental socket-derived stem/progenitor cells (dDSCs). Next, dDSCs were compared with dog BMSCs (dBMSCs) for phenotype characterization. A flow cytometric analysis showed that dDSCs were positive for CD44, CD90, and CD271 but negative for CD34 and CD45, similar to dBMSCs. dDSCs also exhibited osteogenic, adipogenic, and chondrogenic differentiation ability, similar to dBMSCs, with a higher capacity for colony formation, proliferation, and motility than dBMSCs. In addition, an in vivo ectopic bone formation assay showed that dDSCs and dBMSCs both induced hard tissue formation, although only dDSCs formed a fibrous tissue-like structure connected to the newly formed bone. Finally, we tested the ability of dDSCs to regenerate periodontal tissue in a one-wall defect model. The defects in the dDSC-transplanted group (?-TCP/PGA/dDSCs) were regenerated with cementum-like and periodontal ligament-like tissues and alveolar bone, whereas only bony tissue was observed in the control group (?-TCP/PGA). In conclusion, we identified and characterized a population of stem/progenitor cells in granulation tissue obtained from the dental socket that exhibited several characteristics similar to those of BMSCs. Dental sockets could therefore be a novel source for isolating stem/progenitor cells from bone. PMID:25170030

Nakajima, R; Ono, M; Hara, E S; Oida, Y; Shinkawa, S; Pham, H T; Akiyama, K; Sonoyama, W; Maekawa, K; Kuboki, T

2014-11-01

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Alveolar ridge resorption after tooth extraction: A consequence of a fundamental principle of bone physiology  

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Full Text Available It is well established that tooth extraction is followed by a reduction of the buccolingual as well as the apicocoronal dimension of the alveolar ridge. Different measures have been taken to avoid this bone modelling process, such as immediate implant placement and bone grafting, but in most cases with disappointing results. One fundamental principle of bone physiology is the adaptation of bone mass and bone structure to the levels and frequencies of strain. In the present article, it is shown that the reduction of the alveolar ridge dimensions after tooth extraction is a natural consequence of this physiological principle.

Stig Hansson

2012-08-01

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Histometric study of socket healing after tooth extraction in rats treated with diclofenac  

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Full Text Available The purpose of the present study was to investigate if diclofenac administration interferes with the time course of alveolar wound healing in rats. Forty-two Wistar rats were used, 21 rats received 10 mg/kg/day of diclofenac one day before and 4 days after extraction of the right maxillary incisors and 21 rats received saline. The animals were sacrificed 7, 14 and 21 days after tooth extraction. Progressive new bone formation and a decrease in the volume fraction of blood clot and connective tissue from 1 to 3 weeks after tooth extraction was quantified using the histometric point-counting method. Diclofenac treatment caused a significant delay in new bone formation in association with an impairment of blood clot remission/organization.

Yugoshi Luciana Ibara

2002-01-01

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Preventing wrong tooth extraction: experience in development and implementation of an outpatient safety checklist.  

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Extraction of the wrong tooth or teeth is a serious and avoidable clinical error causing harm to the patient. All NHS Trusts in England are required to use a surgical safety checklist in operating theatres to prevent incorrect site surgery and ensure safe management of patients. However, the majority of patients have dental extractions and other oral surgical procedures undertaken on an outpatient basis and these patients are also at risk of having an incorrect site surgical procedure such as a wrong tooth extraction. We describe our experience in developing, introducing and refining a surgical safety checklist for outpatient oral surgery along with the key strategic actions needed to ensure effective cultural change and optimum patient safety in the outpatient setting. PMID:25303583

Saksena, A; Pemberton, M N; Shaw, A; Dickson, S; Ashley, M P

2014-10-10

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A Comparison of Equivalent Doses of Lidocaine and Articaine in Maxillary Posterior Tooth Extractions: Case Series  

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Full Text Available Objectives: Local anaesthesia is the standard of care during dental extractions. With the advent of newer local anesthetic agents, it is often difficult for the clinician to decide which agent would be most efficacious in a given clinical scenario. This study assessed the efficacy of equal-milligram doses of lidocaine and articaine in achieving surgical anaesthesia of maxillary posterior teeth diagnosed with irreversible pulpitis. Material and Methods: This case-series evaluated a total of 41 patients diagnosed with irreversible pulpitis in a maxillary posterior tooth. Patients randomly received an infiltration of either 3.6 mL (72 mg 2% lidocaine with 1:100,000 epinephrine or 1.8 mL (72 mg 4% articaine with 1:100,000 epinephrine in the buccal fold and palatal soft tissue adjacent to the tooth. After 10 minutes, initial anaesthesia of the tooth was assessed by introducing a sterile 27-gauge needle into the gingival tissue adjacent to the tooth, followed by relief of the gingival cuff. Successful treatment was considered to have occurred when the tooth was extracted with no reported pain. Data was analyzed with the Fisher’s exact test, unpaired t-test and normality test. Results: Twenty-one patients received lidocaine and 20 received articaine. Forty of the 41 patients achieved initial anaesthesia 10 minutes after injection: 21 after lidocaine and 19 after articaine (P = 0.488. Pain-free extraction was accomplished in 33 patients: 19 after lidocaine and 14 after articaine buccal and palatal infiltrations (P = 0.226. Conclusions: There was no significant difference in efficacy between equivalent doses of lidocaine and articaine in the anaesthesia of maxillary posterior teeth with irreversible pulpitis.

Christopher C. Friedl

2012-06-01

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Facial vertical changes among patients treated by Edgewise orthodontic technique along with tooth extraction  

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Full Text Available Statement of Problem: Tooth extraction is a common technique in orthodontics and most of the specialists believe that this technique is able to change the facial appearance. Purpose: The aim of this study was to investigate facial vertical changes in orthodontic patients following tooth extraction. Materials and Methods: Thirty patients, after their growth spurt, with CLI malocclusion all treated by a specific orthodontist through Edgewise technique along with the extraction of four first premolars were chosen. Lateral cephalograms of patients, before and after treatment were compared and facial vertical changes and teeth were studied. Results: Anterior and posterior facial heights were increased during treatment. Despite the limited use of intermaxillary elastics, teeth were extruded. The most increase in facial heights was observed in the lower third of face. Patients with longer faces before treatment showed more extrusion of mandibular molars as well as more increase of mandibular slope. Conclusion: Tooth extraction in orthodontic treatments can not guarantee the decrease or even non-increase of facial height. Among patients with long faces, it is particularly suggested to refrain from the application of extrusive orthodontic forces.

Heravi F.

2004-08-01

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Examination of cardiovascular function variables in tooth extraction under local anesthesia  

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Full Text Available Background/Aim. Local anesthesia is the one of the most used procedures in surgical practice. It is used for toot extraction to produce analgesic and anesthetic effects. However, there is a question if it is equally safe to apply a local anesthetic combined with a vasoconstrictor (adrenaline in healthy persons, and in the patients with a certain cardiovascular system disease. The aim of this study was to determine whether there were differences in cardiovascular variables during tooth extraction in healthy persons, and in cardiovascular patients when an anesthetic was applyted with adrenaline, or without it. Methods. The examinees were divided into the group with cardiovascular diseases (CV, n = 57 of II and III type, according to the American Society of Anesthesiologists (ASA qualification, and healthy persons (H, n = 55. Both groups were randomly divided into two subgroups: CVa and Ha - where the anesthetic solution had the vasoconstrictor (3% lidocaine, and 1 : 100 000 adrenaline; CVb and Hb - where the anesthetic solution was without the vasoconstrictor (3% lidocaine. During the preparation for tooth extraction, the application of anesthetics, extraction and relaxation puls (fc, systolic (TAs and diastolic arterial blood pressure (TAd and ECG were registered. Results. The values of fc did not significantly differ among the groups in any measured term. The values of systolic and diastolic blood pressure in the groups CVa and CVb were significantly higher in all the terms of measuring (p < 0.05 from the values in the groups Ha and Hb. A significant increase of TAs was registered only in the phase of tooth extraction in the CVa and CVb group (< 0.05. The values of TAd did not significantly differ between the groups in all the measured terms. Extrasystolic beats were registered in 11 patients of the CV group and in 7 patients of the H group in the phase of anesthetic application or tooth extraction. Conclusion. This research shoved that tooth extraction under local anesthesia did not cause complications in cardiovascular patients who were in II or III ASA qualification group, regardless the presence of a vasoconstrictor in the local anesthetic solution.

Životi?-Vanovi? Mirjana

2006-01-01

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Distinctive Tooth-Extraction Socket Healing: Bisphosphonate Versus Parathyroid Hormone Therapy  

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Background Patients with osteoporosis who receive tooth extractions are typically on either oral bisphosphonate or parathyroid hormone (PTH) therapy. Currently, the consequence of these therapies on hard- and soft-tissue healing in the oral cavity is not clearly defined. The aim of this study is to determine the differences in the therapeutic effect on tooth-extraction wound healing between bisphosphonate and PTH therapies. Methods Maxillary second molars were extracted in Sprague Dawley rats (n = 30), and either bisphosphonate (zoledronate [Zol]), PTH, or saline (vehicle control [VC]) was administered for 10 days (n = 10 per group). Hard-tissue healing was evaluated by microcomputed tomography and histomorphometric analyses. Collagen, blood vessels, inflammatory cell infiltration, and cathepsin K expression were assessed in soft tissue using immunohistochemistry, quantitative polymerase chain reaction, and immunoblotting. Results Both therapies significantly increased bone fill and suppressed vertical bone loss. However, considerably more devital bone was observed in the sockets of rats on Zol versus VC. Although Zol increased the numbers of blood vessels, the total blood vessel area in soft tissue was significantly smaller than in VC. PTH therapy increased osteoblastic bone formation and suppressed osteoclasts. PTH therapy promoted soft-tissue maturation by suppressing inflammation and stimulating collagen deposition. Conclusion Zoledronate therapy deters whereas PTH therapy promotes hard- and soft-tissue healing in the oral cavity, and both therapies prevent vertical bone loss. PMID:23688101

Kuroshima, Shinichiro; Mecano, Rodan B.; Tanoue, Ryuichiro; Koi, Kiyono; Yamashita, Junro

2014-01-01

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Effects of caffeic acid phenethyl ester on palatal mucosal defects and tooth extraction sockets  

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Full Text Available Ahmet Günay,1 Osman Fatih Arpa?,2 Serhat Atilgan,3 Ferhan Yaman,3 Yusuf Atalay,4 ?zzet Acikan3 1Department of Periodontology, Faculty of Dentistry, Dicle University, Diyarbakir, Turkey; 2Department of Periodontology, Faculty of Dentistry, Mustafa Kemal University, Hatay, Turkey; 3Department of Maxillofacial Surgery, Faculty of Dentistry, Dicle University, Diyarbakir, Turkey; 4Department of Maxillofacial Surgery, Faculty of Dentistry, Kocatepe University, Afyon, Turkey Aim: The purpose of this study was to evaluate the effects of caffeic acid phenethyl ester (CAPE on palatal mucosal defects and tooth extraction sockets in an experimental model.Materials and methods: Forty-two male Sprague-Dawley rats with a mean age of 7 weeks and weighing 280–490 g were used in this study. The rats were randomly divided into two groups: group A (the control group, n=21 and group B (the experimental group, n=21. Under anesthesia with ketamine (8 mg/100 g, intraperitoneally, palatal mucosal defects were created and tooth extraction was performed in the rats in groups A and B. Group A received no treatment, whereas group B received CAPE. CAPE was injected daily (10 µmol/kg, intraperitoneally. The rats were killed on days 7, 14, and 30 after the procedures. Palatal mucosa healing and changes in bone tissue and fibrous tissue were evaluated histopathologically.Result: Pairwise comparisons showed no statistically significant difference between days 7 and 14 in either group (P>0.05. At day 30, bone healing was significantly better in group B (CAPE than in group A (control (P<0.05. Fibrinogen levels at day 30 were significantly higher in group A (control than in group B (CAPE (P<0.05. Pairwise comparisons showed no statistically significant difference in palatal mucosa healing levels between days 7 and 14 in both groups (P>0.05.Conclusion: In conclusion, the findings of this study suggest that CAPE can significantly improve tooth socket healing. Keywords: caffeic acid phenyl ester, palatal mucosa, tooth extraction socket, healing

Günay A

2014-10-01

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Inflammatory myofibroblastic tumor of maxilla showing sarcomatous change in an edentulous site with a history of tooth extraction following periodontitis: A case report with discussion.  

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Inflammatory myofibroblastic tumor (IMT) is a rare tumor of uncertain origin with variable biological behavior ranging from reactive lesions to highly aggressive malignancy. Oral IMTs are extremely rare and only 25 cases had been reported so far. A case of IMT with sarcomatous transformation in an extraction site with a history of tooth extraction following tooth mobility of an upper left molar tooth is presented here. The tooth was extracted following a complaint of gingival swelling and mobility of tooth. Though malignant transformation in IMTs had been documented in the extra oral sites, wide search of associated literature suggests, this is the first case of oral IMT showing malignant change associated with gingiva. The case report attempts to highlight the variant possibilities of tooth mobility other than periodontitis and the importance of assessing the primary cause of such conditions. PMID:25024554

Biniraj, K R; Janardhanan, Mahija

2014-05-01

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

International Nuclear Information System (INIS)

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)

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Effects of local and whole body irradiation on the appearance of osteoblasts during wound healing in tooth extraction sockets in rats  

International Nuclear Information System (INIS)

Irradiation before tooth extraction delays wound healing in the alveolar socket. This study examined the influences of local and whole body irradiation before tooth extraction on appearance of osteoblasts in the alveolar bone of rat maxillary first molars because bone formation is observed at the initial phase of wound healing. Several osteoblasts were generated 3 days after tooth extraction, and the number of cells increased day by day. Morphological studies showed there were little differences between local irradiation and non-irradiated controls. In contrast, the extraction wound in the whole body irradiation group showed delayed healing, and there was poor granulation tissue and very few osteoblasts at the bottom of the socket. An ultrastructural study showed that the osteoblasts in the extraction socket of whole body irradiation rats were smaller, and had poorly developed organelles. Injection of bone marrow cells to whole body-irradiated animals immediately after tooth extraction partially restored the number of osteoblasts. New periosteal bone formations outside of sockets showed little delay in the whole body irradiation group. These findings suggest that bone formation in the wound healing of extraction socket requires bone marrow cells from hematopoietic organs such as the bone marrow as well as local sources around the alveolar socket, during the initial phase of wound healing. (author)

 
 
 
 
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The influence of topic and systemic administration of copaiba oil on the alveolar wound healing after tooth extraction in rats.  

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The Copaiba oil has been used as an auxiliary treatment of inflammations, skin disorders and stomach ulcers, however, in dentistry, this "alternative" medicine has not been investigated yet. The purpose of this study was to evaluate the influence of topic and systemic administration of copaiba oil on the alveolar wound healing after tooth extraction. Twenty-eight wistar male rats had their lower first molar teeth extracted. Subsequently, they were divided in four groups, according to the treatment performed: (a) alveolar socket irrigation with copaiba oil; (b) alveolar socket irrigation with physiological serum; (c) daily gavage with copaiba oil or (d) daily gavage with physiological serum. After the sacrifice, the mandibles were removed and processed in order to obtain decalcified histological sections. The results demonstrated high level of epithelial migration, small number of inflammatory cells and vascular enhancement in the animals which received systemic administration of copaiba oil. The rats treated with topic administration of copaiba oil presented ulcerations and large number of inflammatory cells. An increased bone neoformation was observed in both groups treated with copaiba oil when compared with placebo group. It could be concluded that topic or systemic administration of copaiba oil leads to a better alveolar bone healing, however the topic application on connective tissue should be carefully considered, regarding the whole socket wound healing. Key words:Alveolar wound healing, oil-resin, copaiba. PMID:24455075

Dias-da-Silva, Marco A; Pereira, Andresa C; Marin, Miguel Cc; Salgado, Miguel Ac

2013-10-01

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Comparative Study of Acetaminophen, Ibuprofen and Combination Effects for Pain Relief Following Tooth Extraction in Children under Local Anesthesia  

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Full Text Available Introduction & Objective: It is clear that tooth extraction is painful. Different drugs with various functions have been used in order to relieve the pain after extraction. Ibuprofen is a non-narcotic analgesic and acetaminophen is considered as one of the most consumption anti-inflammatory drugs and is administrated to relieve moderate to severe pains. Our purpose is comparing the effects of acetaminophen, ibuprofen and combination of them to relieve the teeth pain due to extraction under local anesthesia. Materials & Methods: In this randomized clinical trial, we divided 105 children (6-11 years old referred to pediatrics ward of dental faculty of Hamadan University into 3 groups of 35 after getting their parent's consents, taking, their history and weighing them. Group1: received acetaminophen syrup with dose of 15mg/kg, group2: received ibuprofen syrup with dose of 5 mg/kg, and group3 received acetaminophen syrup with dose of 7.5mg/kg and ibuprofen syrup with dose of 2.5mg/kg. . One hour before and 15 min after tooth extraction, severity of their pain was evaluated according to table(CHEOPS.Drug effects in every group was studied by c2 , t-test and Mann Whitney U test. Results: Age average of the children under survey in the group of acetaminophen syrup was 8.62±1.81 years old and in the group of ibuprofen syrup was 8.45±1.68 years old, and in the group of acetaminophen with ibuprofen was equal with 8.71±1.27 years old. Sex combination of the under survey children in the group of acetaminophen syrup was 51.4% / 48.6% (female/male, in the group of ibuprofen syrup was 51.4%/48.6%, and in the group of acetaminophen syrup with ibuprofen syrup was 65.7%/34.3%. Grade average of toothache immediately after extraction in the group treated with acetaminophen syrup was 33.19 and, in group treated with ibuprofen syrup equaled 37.81, and in the group treated with acetaminophen syrup with ibuprofen syrup was 47.86. Grade average of toothache 15 min after extraction in the group 1 was 35.1, in the second group was 35.9, and in the third group was 40.83.Conclusion: The group received ibuprofen syrup and in the group received acetaminophen syrup in comparison with the group received acetaminophen with ibuprofen on the instant and 15 min after extraction showed much more relieved effect (P<0.05. No meaningful statistic differences were observed between the group received acetaminophen I5 mg/kg and the group received ibuprofen 5 mg/kg.(Sci J Hamadan Univ Med Sci 2012;18(4:5-9

Z. Pahlavani

2012-01-01

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Inflammatory dentigerous cysts of children treated by tooth extraction and decompression--report of four cases.  

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Inflammatory dentigerous cysts are only found in the mixed dentition. The four cases presented here illustrate the uncomplicated behavior of these cysts when properly treated. By extracting the infected primary teeth, opening the cyst and ensuring continuous drainage, it is possible to achieve spontaneous eruption of the involved permanent teeth into the dental arch even if they are badly dislocated. Simultaneous with the eruption of the permanent teeth, ossification of the bony defect can take place. The reparatory process is completed in one to two years. PMID:16163275

Kozelj, V; Sotosek, B

1999-12-11

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Immediate Placement of Implants in Tooth Extraction Sockets in the Presence of Periapical Lesions with or without Er:YAG Laser Irradiation  

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Full Text Available Background and aims. Immediate placement of implant into fresh extraction sockets has become a common and accept-able clinical method. Different clinical studies have reported great success and survival rates in immediate implant placement in extraction sockets with periapical lesions. Theaim of this study was to investigate the effect of Er:YAG laser irradiation on success rate of immediate implant placement in tooth extraction sockets with chronic periapical lesions.Materials and methods. Thirty patients requiring a single-root tooth extraction with chronic periapical lesions were in-cluded in this prospective, randomized, clinical trial and divided into control (n=15 and test (n=15 groups. After tooth extrac-tion, the implant were placed with guided bone regeneration in the control group after periapical curettage and socket irrigation and in the test group, irrigation of the periapical region was accompaniedwith Er:YAG laser for 1 min at 100 mJ, 10 Hz, 12.73 J/cm2. Radiographic (using standard long-cone parallel and clinical parameters (plaque index [PI], modified bleeding index [mBI], probing depth [PD], keratinized mucosa [KM], Periotest values [PTV] were assessed at baseline and 1, 3 and 6 months after implant placement. Data was analyzed with t-test and chi-squared test. The level of significance was set at 5%.Results. A survival rate of 100% was observed for all the implants placed at the sixth-month follow-up, with no significant differences between clinical and radiographic parameters of the control and test groups at different time intervals (P>0.05.Conclusion. At 6-month follow-up, there were no complications in soft and hard tissue healing processes after immediate placement of implants into fresh extraction sockets with chronic periapical lesions, regardless of Er:YAG laser irradiation.

Reza Birang

2012-06-01

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Tooth Abrasion and Tooth Erosion  

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... protects the innermost part of the tooth, the pulp, which contains nerves and blood vessels. Abrasion and erosion also can affect how your teeth look. Diagnosis Your dentist can examine your teeth ...

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Efeito comparativo entre clonixinato de lisina e paracetamol no controle da dor pós-exodontia / Comparison between lysine and paracetamol for post tooth extraction pain control  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: A exodontia é praticada desde os primórdios da humanidade como forma de resolver cirurgicamente os problemas dentários. Porém, como todo procedimento cirúrgico, ela promove um processo inflamatório reacional que se apresenta clinicamente com dor. Muitos fármacos têm sido u [...] sados no intuito de minimizar o desconforto pós-operatório, porém um protocolo para o seu controle ainda não está estabelecido. Este estudo teve como objetivo avaliar o efeito analgésico do clonixinato de lisina e paracetamol no controle de dor pós-exodontia. MÉTODO: Estudo duplamente encoberto e randomizado com 40 pacientes atendidos no Ambulatório de Cirurgia I no Departamento de Odontologia da Universidade Federal de Sergipe (DOD/UFS) que necessitaram de extrações por via alveolar em hemiarcadas diferentes utilizando clonixinato de lisina (125 mg) três vezes ao dia ou paracetamol (750 mg) quatro vezes ao dia, ambos por três dias no pós-operatório. A dor foi avaliada nas primeiras 24 e 48h com o uso da escala analógica visual. Os dados foram submetidos aos testes estatísticos t de Student e de Friedman. RESULTADOS: Não houve diferenças estatisticamente significantes entre idade, em relação aos gêneros e em relação à intensidade da dor. CONCLUSÃO: Tanto o clonixinato de lisina como o paracetamol foi eficaz para o controle da dor pós-exodontia. Abstract in english BACKGROUND AND OBJECTIVES: Tooth extraction is practiced since the early days of mankind to surgically solve dental problems. However, as any surgical procedure, it promotes an inflammatory reaction with clinical presentation of pain. Several drugs have been used to minimize postoperative discomfort [...] ; however there is still no established protocol for its control. This study aimed at evaluating the analgesic effect of lysine and paracetamol to control post tooth extraction pain. METHOD: Double blind randomized study with 40 patients seen by the Surgical Outpatient Setting I, Dentistry Department, Federal University of Sergipe (DOD/UFS), who needed alveolar extractions in different hemiarcades using lysine (125 mg) three times a day or paracetamol (750 mg) four times a day, both during three postoperative days. Pain was evaluated at 24 and 48 hours with the visual analog scale. Data were submitted to Student's t and Friedman statistical tests. RESULTS: There have been no statistically significant differences in age, gender and pain intensity. CONCLUSION: Both lysine and paracetamol were effective to control post tooth extraction pain.

Klinger de Souza, Amorim; Lucas Celestino Guerzet, Ayres; Rafael Soares da, Cunha; Liane Maciel de Almeida, Souza; Mônica Silveira, Paixao; Francisco, Groppo.

27

Efeito comparativo entre clonixinato de lisina e paracetamol no controle da dor pós-exodontia / Comparison between lysine and paracetamol for post tooth extraction pain control  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: A exodontia é praticada desde os primórdios da humanidade como forma de resolver cirurgicamente os problemas dentários. Porém, como todo procedimento cirúrgico, ela promove um processo inflamatório reacional que se apresenta clinicamente com dor. Muitos fármacos têm sido u [...] sados no intuito de minimizar o desconforto pós-operatório, porém um protocolo para o seu controle ainda não está estabelecido. Este estudo teve como objetivo avaliar o efeito analgésico do clonixinato de lisina e paracetamol no controle de dor pós-exodontia. MÉTODO: Estudo duplamente encoberto e randomizado com 40 pacientes atendidos no Ambulatório de Cirurgia I no Departamento de Odontologia da Universidade Federal de Sergipe (DOD/UFS) que necessitaram de extrações por via alveolar em hemiarcadas diferentes utilizando clonixinato de lisina (125 mg) três vezes ao dia ou paracetamol (750 mg) quatro vezes ao dia, ambos por três dias no pós-operatório. A dor foi avaliada nas primeiras 24 e 48h com o uso da escala analógica visual. Os dados foram submetidos aos testes estatísticos t de Student e de Friedman. RESULTADOS: Não houve diferenças estatisticamente significantes entre idade, em relação aos gêneros e em relação à intensidade da dor. CONCLUSÃO: Tanto o clonixinato de lisina como o paracetamol foi eficaz para o controle da dor pós-exodontia. Abstract in english BACKGROUND AND OBJECTIVES: Tooth extraction is practiced since the early days of mankind to surgically solve dental problems. However, as any surgical procedure, it promotes an inflammatory reaction with clinical presentation of pain. Several drugs have been used to minimize postoperative discomfort [...] ; however there is still no established protocol for its control. This study aimed at evaluating the analgesic effect of lysine and paracetamol to control post tooth extraction pain. METHOD: Double blind randomized study with 40 patients seen by the Surgical Outpatient Setting I, Dentistry Department, Federal University of Sergipe (DOD/UFS), who needed alveolar extractions in different hemiarcades using lysine (125 mg) three times a day or paracetamol (750 mg) four times a day, both during three postoperative days. Pain was evaluated at 24 and 48 hours with the visual analog scale. Data were submitted to Student's t and Friedman statistical tests. RESULTS: There have been no statistically significant differences in age, gender and pain intensity. CONCLUSION: Both lysine and paracetamol were effective to control post tooth extraction pain.

Klinger de Souza, Amorim; Lucas Celestino Guerzet, Ayres; Rafael Soares da, Cunha; Liane Maciel de Almeida, Souza; Mônica Silveira, Paixao; Francisco, Groppo.

2012-12-01

28

Dental Caries (Tooth Decay)  

Science.gov (United States)

... Find Data by Topic > Dental Caries (Tooth Decay) Dental Caries (Tooth Decay) Main Content Dental caries (tooth decay) remains the most prevalent chronic ... important source of information on oral health and dental care in the United States since the early ...

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A 5- Year Comparison of Marginal Bone Level Following Immediate Loading of Single-Tooth Implants Placed in Healed Alveolar Ridges and Extraction Sockets in the Maxilla.  

Directory of Open Access Journals (Sweden)

Full Text Available AbstractPurpose: The aim of present investigation was to evaluate marginal bone level after 5-year follow-up of implants placed in healed ridges and fresh extraction sockets in maxilla with immediate loading protocol.Materials and Methods: Thirty-six patients in need of a single tooth replacement in the anterior maxilla received 42 Astra Tech implants (Astra Tech Implant system™, Dentsply Implants, Mölndal, Sweden. Implants were placed in healed ridges (group I or immediately into extraction sockets (group II. Implants were restored and placed into functional loading immediately by using a prefabricated abutment. Marginal bone level relative to the implant reference point was recorded at implant placement, crown cementation, 12, 36 and 60 months following loading using intra-oral radiographs. Measurements were made on the mesial and distal sides of each implantResults: Overall, two implants were lost from the group II, before final crown cementation: they were excluded from the study and all remaining implants osseointegrated successfully after 5 years of functional loading. The mean change in marginal bone loss after implant placement was 0.267±0.161 for one year, and 0.265±0.171 for three years and 0.213±0.185 for five years in extraction sockets and was 0.266±0.176 for one year and 0.219±0.175 for three years and 0.194±0.172 for five years in healed ridges group. Significant reduction of marginal bone loss was more pronounced in implants inserted in healed ridges (P

AntoineNicolasBerberi

2014-01-01

30

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Men's Oral Health Check Menstrual Calendar for Tooth Extraction Why is Oral Health Important for Men? What is a Composite Resin ( ...

31

Cigarette smoke inhalation influences bone healing of post-extraction tooth socket: a histometric study in rats  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O objetivo do estudo foi avaliar a influência da inalação da fumaça de cigarros (IFC) sobre os períodos iniciais de reparo ósseo alveolar. Quarenta ratos Wistar foram aleatoriamente divididos em teste: animais expostos à IFC, que se iniciou 3 dias antes das extrações mantendo-se até o sacrifício (n= [...] 20)e controle (animais que não foram expostos à IFC; n=20). Os animais tiveram seus segundos molares inferiores extraídos bilateralmente (n=5/grupo/período) e foram sacrificados nos dias 3, 7, 10 e 14 dias após a cirurgia. Imagens digitalizadas foram analisadas de acordo com os seguintes parâmetros histométricos: tecido osteóide (OT), área remanescente (RA), tecido mineralizado (MT) e tecido não mineralizado (NMT) em cada alvéolo. Análise intergrupo mostrou que não houve diferença estatisticamente significante aos 3 dias (p>0,05) para todos os parâmetros. Aos 7 dias, a IFC influenciou negativamente (p?0,05) o preenchimento ósseo mostrando diferença estatisticamente significante para os parâmetros tecido não mineralizado e defeito remanescente (MT: 36%, NMT: 53%, RA: 12%; and MT: 39%, NMT: 29%, RA: 32%, para controle e teste, respectivamente). No entanto, não houve diferença estatisticamente significante (p>0,05) aos 10 e 14 dias. Conclui-se que a IFC pode afetar o reparo ósseo alveolar inicial, o que pode ser crítico para a quantidade e qualidade da nova formação óssea em fumantes. Abstract in english The aim of this study was to evaluate, histometrically, the bone healing of the molar extraction socket just after cigarette smoke inhalation (CSI). Forty male Wistar rats were randomly assigned to a test group (animals exposed to CSI, starting 3 days before teeth extraction and maintained until sac [...] rifice; n=20) and a control group (animals never exposed to CSI; n=20). Second mandibular molars were bilaterally extracted and the animals (n=5/group/period) were sacrificed at 3, 7, 10 and 14 days after surgery. Digital images were analyzed according to the following histometric parameters: osteoid tissue (OT), remaining area (RA), mineralized tissue (MT) and non-mineralized tissue (NMT) in the molar socket. Intergroup analysis showed no significant differences at day 3 (p>0.05) for all parameters. On the 7th day, CSI affected negatively (p0.05) were found at days 10 and 14. It may be concluded that CSI may affect socket healing from the early events involved in the healing process, which may be critical for the amount and quality of new-bone formation in smokers.

Ana Paula Oliveira, Giorgetti; João Batista, César Neto; Márcio Zaffalon, Casati; Enílson Antonio, Sallum; Francisco Humberto, Nociti Júnior.

32

Fate of the buccal bone at implants placed early, delayed, or late after tooth extraction analyzed by cone beam CT : 10-year results from a randomized, controlled, clinical study  

DEFF Research Database (Denmark)

AIM: To present 10-year cone beam CT (CBCT) data on the fate of buccal bone at single-tooth implants placed early, delayed, or late after tooth extraction. MATERIAL AND METHODS: Sixty-three of 72 patients, originally randomly allocated to three equal-size groups, received a single-tooth implant on average 10 days (Ea; N = 22), 3 months (De; N = 22), or 1.5 years (La; N = 19) after tooth extraction. Healing abutments were mounted after a 3-month period of submerged healing and metalceramic crowns were cemented after one additional month. At the second stage surgery, presence of buccal bone defects (dehiscences or intrabony) and their dimensions were registered. CBCT scans recorded with a Scanora(®) 3D unit and standardized periapical (PA) radiographs of the implants were obtained at the 10-year control. Interproximal bone levels (i.e., the distance from the implant platform to the first bone-to-implant contact; BIC) measured in CBCT image sections and PA were compared, and the buccal bone level was determinedin the CBCT images. RESULTS: Two Ea and one De implants failed to osseointegrate. Forty-nine patients attended the 10-year control and due to poor quality of 5 CBCT scans, useful CBCT images were available from 44 patients (Ea:12, De:17, La:15). No significant differences between CBCT and PA images in measurements of the interproximal bone levels were observed. Ten years after implant placement, BIC at the buccal aspect was located on average 2 mm apically to the implant platform (2.39 ± 1.06 mm [median = 2.36] for Ea, 2.22 ± 0.99 mm [median = 2.16] for De, and 1.85 ± 0.65 mm [median = 1.95] for La implants) with no significant difference among the groups (P = 0.20). Mean buccal bone level (bBL) for implants with an intrabony or a dehiscence defect at second stage surgery was 2.51 ± 1.12 mm [median = 2.70] and 2.84 ± 0.70 mm [median = 2.79], respectively, while 1.78 ± 0.74 mm [median = 1.93] for the implants with no defect. The difference in bBL between the implants without a defect and those with a dehiscence was significant at 10 years (P = 0.0005). CONCLUSION: Time of placement of single-tooth implants after tooth extraction did not significantly influence the peri-implant buccal bone level, while presence of a buccal bone dehiscence at second stage surgery resulted in significantly more apically located BIC buccally at 10 years.

Schropp, Lars; Wenzel, Ann

2014-01-01

33

Preemptive analgesia of dexamethasone as compared to ketorolac tromethamine in simple tooth extractions / Analgesia preemptiva da dexametasona em relação ao cetorolaco de trometamol em extrações dentárias simples  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: Entendendo que a dor é o maior transtorno pós-operatório, diante da necessidade de estabelecer um protocolo terapêutico do seu controle pós-exodontias e dos poucos estudos comparando esses fármacos é que se justifica o trabalho. O objetivo deste estudo foi avaliar e compa [...] rar o efeito analgésico preemptivo de dois fármacos, ambos administrados em dose única. MÉTODOS: A pesquisa tem caráter experimental a partir de um ensaio clínico com seres humanos. Trata-se de um estudo duplamente encoberto, cruzado e randomizado, com 51 pacientes atendidos no Ambulatório de Cirurgia Oral do Departamento de Odontologia da Universidade Federal de Sergipe (DOD/UFS), entre setembro de 2011 e setembro de 2012, que necessitaram de extrações simples por via alveolar em hemiarcadas diferentes utilizando dexametasona (4mg) e cetorolaco de trometamol (10mg), uma hora antes da cirurgia distintamente. A dor foi avaliada nas primeiras 24 e 48h, com o uso da escala analógica visual. O intervalo de 8 dias foi estabelecido entre as exodontias. RESULTADOS: Não houve diferenças estatisticamente significantes no teste Exato de Fisher (p>0,05) e Friedman (p>0,05), nem entre os fármacos (considerando um mesmo período) nem entre os períodos (considerando o mesmo fármaco). CONCLUSÃO: Não existem diferenças significativas entre os fármacos e os períodos observados. Abstract in english BACKGROUND AND OBJECTIVES: Understanding that pain is the most important postoperative problem, in face to the need of establishing a therapeutic protocol to control post-tooth extraction pain and due to few studies comparing these drugs is that our study is justified. This study aimed at evaluatin [...] g and at comparing the preemptive analgesic effect of two drugs, both administered in bolus. METHODS: This is an experimental research as from a clinical trial with human beings. It is a double-blind, crossover and randomized trial with 51 patients seen by the Oral Surgery Ambulatory of the Dentistry Department, Federal University of Sergipe (DOD/UFS), between September 2011 and September 2012, who needed simple alveolar extractions in different hemiarcades, using dexamethasone (4mg) or ketorolac tromethamine (10mg), one hour before surgery distinctively. Pain was evaluated in the first 24 and 48 hours with the visual analog scale. The interval of eight days was established between extractions. RESULTS: There have been no statistically significant differences by Fisher (p>0.05) and Friedman (p>0.05) Exact tests, or between drugs (considering a same period) or between periods (considering the same drug). CONCLUSION: There are no significant differences between drugs and observed periods.

Rodrigo Mathias Freire de Menezes, Carneiro; Rafael Soares da, Cunha; Liane Maciel de Almeida, Souza; Francisco, Groppo.

2014-04-01

34

Preemptive analgesia of dexamethasone as compared to ketorolac tromethamine in simple tooth extractions / Analgesia preemptiva da dexametasona em relação ao cetorolaco de trometamol em extrações dentárias simples  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: Entendendo que a dor é o maior transtorno pós-operatório, diante da necessidade de estabelecer um protocolo terapêutico do seu controle pós-exodontias e dos poucos estudos comparando esses fármacos é que se justifica o trabalho. O objetivo deste estudo foi avaliar e compa [...] rar o efeito analgésico preemptivo de dois fármacos, ambos administrados em dose única. MÉTODOS: A pesquisa tem caráter experimental a partir de um ensaio clínico com seres humanos. Trata-se de um estudo duplamente encoberto, cruzado e randomizado, com 51 pacientes atendidos no Ambulatório de Cirurgia Oral do Departamento de Odontologia da Universidade Federal de Sergipe (DOD/UFS), entre setembro de 2011 e setembro de 2012, que necessitaram de extrações simples por via alveolar em hemiarcadas diferentes utilizando dexametasona (4mg) e cetorolaco de trometamol (10mg), uma hora antes da cirurgia distintamente. A dor foi avaliada nas primeiras 24 e 48h, com o uso da escala analógica visual. O intervalo de 8 dias foi estabelecido entre as exodontias. RESULTADOS: Não houve diferenças estatisticamente significantes no teste Exato de Fisher (p>0,05) e Friedman (p>0,05), nem entre os fármacos (considerando um mesmo período) nem entre os períodos (considerando o mesmo fármaco). CONCLUSÃO: Não existem diferenças significativas entre os fármacos e os períodos observados. Abstract in english BACKGROUND AND OBJECTIVES: Understanding that pain is the most important postoperative problem, in face to the need of establishing a therapeutic protocol to control post-tooth extraction pain and due to few studies comparing these drugs is that our study is justified. This study aimed at evaluatin [...] g and at comparing the preemptive analgesic effect of two drugs, both administered in bolus. METHODS: This is an experimental research as from a clinical trial with human beings. It is a double-blind, crossover and randomized trial with 51 patients seen by the Oral Surgery Ambulatory of the Dentistry Department, Federal University of Sergipe (DOD/UFS), between September 2011 and September 2012, who needed simple alveolar extractions in different hemiarcades, using dexamethasone (4mg) or ketorolac tromethamine (10mg), one hour before surgery distinctively. Pain was evaluated in the first 24 and 48 hours with the visual analog scale. The interval of eight days was established between extractions. RESULTS: There have been no statistically significant differences by Fisher (p>0.05) and Friedman (p>0.05) Exact tests, or between drugs (considering a same period) or between periods (considering the same drug). CONCLUSION: There are no significant differences between drugs and observed periods.

Rodrigo Mathias Freire de Menezes, Carneiro; Rafael Soares da, Cunha; Liane Maciel de Almeida, Souza; Francisco, Groppo.

35

Effect of acemannan, an extracted polysaccharide from Aloe vera, on BMSCs proliferation, differentiation, extracellular matrix synthesis, mineralization, and bone formation in a tooth extraction model.  

Science.gov (United States)

Aloe vera is a traditional wound healing medicine. We hypothesized acemannan, a polysaccharide extracted from Aloe vera gel, could affect bone formation. Primary rat bone marrow stromal cells (BMSCs) were treated with various concentrations of acemannan. New DNA synthesis, VEGF, BMP-2, alkaline phosphatase activity, bone sialoprotein, osteopontin expression, and mineralization were determined by [(3)H] thymidine incorporation assay, ELISA, biochemical assay, western blotting, and Alizarin Red staining, respectively. In an animal study, mandibular right incisors of male Sprague-Dawley rats were extracted and an acemannan treated sponge was placed in the socket. After 1, 2, and 4 weeks, the mandibles were dissected. Bone formation was evaluated by dual-energy X-ray absorptiometry and histopathological examination. The in vitro results revealed acemannan significantly increased BMSC proliferation, VEGF, BMP-2, alkaline phosphatase activity, bone sialoprotein and osteopontin expression, and mineralization. In-vivo results showed acemannan-treated groups had higher bone mineral density and faster bone healing compared with untreated controls. A substantial ingrowth of bone trabeculae was observed in acemannan-treated groups. These data suggest acemannan could function as a bioactive molecule inducing bone formation by stimulating BMSCs proliferation, differentiation into osteoblasts, and extracellular matrix synthesis. Acemannan could be a candidate natural biomaterial for bone regeneration. PMID:23315202

Boonyagul, Sani; Banlunara, Wijit; Sangvanich, Polkit; Thunyakitpisal, Pasutha

2014-07-01

36

Multilobed mesiodens: a supernumerary tooth with unusual morphology.  

Science.gov (United States)

An 8-year-old boy came with a chief complaint of an abnormally shaped tooth situated in upper front teeth region. On examination a supernumerary tooth with multiple lobes was present palatally to the maxillary right permanent central incisor. The morphology of the tooth crown was found to be unusual due to the presence of five lobes in the crown portion. Because of the supernumerary tooth, the permanent right central incisor was displaced labially. Radiographic examination showed a completely formed supernumerary tooth with dilacerated root. On the basis of clinical and radiographic examination, the supernumerary tooth was diagnosed as multilobed mesiodens. Since patient expressed dissatisfaction with the presence of supernumerary tooth, it was decided to extract this mesiodens followed by orthodontic treatment for alignment of labially placed maxillary right permanent central incisor. PMID:23391956

Dave, Bhavna; Patel, Jalark; Swadas, Milan; Mallikarjuna, Rachappa

2013-01-01

37

Automating digital leaf measurement: the tooth, the whole tooth, and nothing but the tooth.  

Science.gov (United States)

Many species of plants produce leaves with distinct teeth around their margins. The presence and nature of these teeth can often help botanists to identify species. Moreover, it has long been known that more species native to colder regions have teeth than species native to warmer regions. It has therefore been suggested that fossilized remains of leaves can be used as a proxy for ancient climate reconstruction. Similar studies on living plants can help our understanding of the relationships. The required analysis of leaves typically involves considerable manual effort, which in practice limits the number of leaves that are analyzed, potentially reducing the power of the results. In this work, we describe a novel algorithm to automate the marginal tooth analysis of leaves found in digital images. We demonstrate our methods on a large set of images of whole herbarium specimens collected from Tilia trees (also known as lime, linden or basswood). We chose the genus Tilia as its constituent species have toothed leaves of varied size and shape. In a previous study we extracted c.1600 leaves automatically from a set of c.1100 images. Our new algorithm locates teeth on the margins of such leaves and extracts features such as each tooth's area, perimeter and internal angles, as well as counting them. We evaluate an implementation of our algorithm's performance against a manually analyzed subset of the images. We found that the algorithm achieves an accuracy of 85% for counting teeth and 75% for estimating tooth area. We also demonstrate that the automatically extracted features are sufficient to identify different species of Tilia using a simple linear discriminant analysis, and that the features relating to teeth are the most useful. PMID:22870286

Corney, David P A; Tang, H Lilian; Clark, Jonathan Y; Hu, Yin; Jin, Jing

2012-01-01

38

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Men's Oral Health Check Menstrual Calendar for Tooth Extraction What is ... Home | InfoBites | Find a Dentist | Your Family's Oral Health | Newsroom | RSS About AGD | Contact AGD | Site Map | ...

39

Cracked Tooth Syndrome  

Science.gov (United States)

... That's because these teeth absorb most of the forces of chewing. Some people grind or clench their ... Symptoms The tooth may hurt sometimes when you bite or chew. The sensitivity or pain can be ...

40

How a Tooth Decays  

Science.gov (United States)

... tooth's outer surface. This process is known as demineralization. The first sign of this is a chalky ... repair itself. 3. Enamel Decay 4. Dentin Decay Demineralization continues. Enamel starts to break down. Once the ...

 
 
 
 
41

Functional tooth regenerative therapy: tooth tissue regeneration and whole-tooth replacement.  

Science.gov (United States)

Oral and general health is compromised by irreversible dental problems, including dental caries, periodontal disease and tooth injury. Regenerative therapy for tooth tissue repair and whole-tooth replacement is currently considered a novel therapeutic concept with the potential for the full recovery of tooth function. Several types of stem cells and cell-activating cytokines have been identified in oral tissues. These cells are thought to be candidate cell sources for tooth tissue regenerative therapies because they have the ability to differentiate into tooth tissues in vitro and in vivo. Whole-tooth replacement therapy is regarded as an important model for the development of an organ regenerative concept. A novel three-dimensional cell-manipulation method, designated the organ germ method, has been developed to recapitulate organogenesis. This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions. A bioengineered tooth germ can generate a structurally correct tooth in vitro and erupt successfully with the correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was successfully engrafted into an adult jawbone through bone integration. Such bioengineered teeth were able to perform normal physiological tooth functions, such as developing a masticatory potential in response to mechanical stress and a perceptive potential for noxious stimuli. In this review, we describe recent findings and technologies underpinning tooth regenerative therapy. PMID:25052182

Oshima, Masamitsu; Tsuji, Takashi

2014-07-01

42

Learning about Charcot-Marie-Tooth Disease  

Science.gov (United States)

... to Further Research 2003 News Release Learning About Charcot-Marie-Tooth Disease What do we know about ... Marie-Tooth Disease What do we know about Charcot-Marie-Tooth disease? Charcot-Marie-Tooth disease (CMT) ...

43

The effect of permanent grafting materials on the preservation of the buccal bone plate after tooth extraction: an experimental study in the dog.  

LENUS (Irish Health Repository)

The aim of the present study was to evaluate the effects of a novel bone substitute system (Natix(®)), consisting of porous titanium granules (PTG) and a bovine-derived xenograft (Bio-Oss(®)), on hard tissue remodelling following their placement into fresh extraction sockets in dogs.

Bashara, Haitham

2012-08-01

44

Ridge preservation with acellular dermal matrix and anorganic bone matrix cell-binding peptide P-15 after tooth extraction in humans. A histologic and morphometric study  

Directory of Open Access Journals (Sweden)

Full Text Available Aim: The aim of this study was to analyze by histomorphometric parameters the use of acellular dermal matrix (ADM with or without anorganic bovine bone matrix (ABM / synthetic cell-binding peptide P-15 in the formation of bone in human alveoli. Materials and methods: Eighteen patients in need of extraction of maxillary anterior teeth were selected and randomly assigned to the test group (ADM plus ABM/P-15 or the control group (ADM only. Histomorphometric measurements and histological analysis were recorded about 6 months after ridge preservation procedures in ten patients. The amount of newly formed bone, the most recently formed bone, fibrous tissue plus marrow spaces and remaining graft particles were measured and analyzed. Results: At 6 months, the new bone area parameter and the percentage of fibrous tissue plus marrow space areas showed higher values to the control group, and statistically significant differences when compared with the test group (p=0.03. Conclusion: The ADM acted as a membrane. The association of ABM/P-15 with ADM resulted in new bone formation within the alveoli, but the results were not considered relevant when used in this indication.

Arthur B. Novaes Jr

2012-06-01

45

Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel  

Science.gov (United States)

This thesis deals with advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum measurement conditions inside the EPR cavity, post process the measured spectrum with functional simulation of dosimetric and other interfering signals, and reconstruct dose. By using this technique, retrospective gamma radiation exposures as low as 80 +/- 30 mGy have been successfully deciphered. The notion of dose modifier was introduced in EPR biodosimetry for low dose measurements. It has been demonstrated that by using the modified zero added dose (MZAD) technique for low radiation exposures, doses in the 100 mGy range can be easily reconstructed in teeth which were previously thought useless for EPR dosimetry. Also the use of a dose modifier makes robust dose reconstruction possible for higher radiation exposures. The EPR dosimetry technique was also developed for tooth samples extracted from rodents, which represent small tooth sizing. EPR doses in the molars, extracted from mice irradiated with whole body exposures, were reassessed and shown to be correct within the experimental uncertainty. The sensitivity of human tooth enamel for neutron irradiation, obtained from the 3 MV McMaster K. N. Van de Graaff accelerator, was also studied. For the first time this work has shown that the neutron sensitivity of the tooth enamel is approximately 1/10th of the equivalent gamma sensitivity. Parametric studies for neutron dose rate and neutron energy within the available range of the accelerator, showed no impact on the sensitivity of the tooth enamel. Therefore, tooth enamel can be used as a dosimeter for both neutrons as well as gamma radiation. We will continue experiments to develop this endpoint as a sensitive accident or emergency tool for our response capabilities.

Khan, Rao F. H.

46

Role of multiple cusps in tooth fracture.  

Science.gov (United States)

The role of multiple cusps in the biomechanics of human molar tooth fracture is analysed. A model with four cusps at the bite surface replaces the single dome structure used in previous simulations. Extended finite element modelling, with provision to embed longitudinal cracks into the enamel walls, enables full analysis of crack propagation from initial extension to final failure. The cracks propagate longitudinally around the enamel side walls from starter cracks placed either at the top surface (radial cracks) or from the tooth base (margin cracks). A feature of the crack evolution is its stability, meaning that extension occurs steadily with increasing applied force. Predictions from the model are validated by comparison with experimental data from earlier publications, in which crack development was followed in situ during occlusal loading of extracted human molars. The results show substantial increase in critical forces to produce longitudinal fractures with number of cuspal contacts, indicating a capacity for an individual tooth to spread the load during mastication. It is argued that explicit critical force equations derived in previous studies remain valid, at the least as a means for comparing the capacity for teeth of different dimensions to sustain high bite forces. PMID:24755003

Barani, Amir; Bush, Mark B; Lawn, Brian R

2014-07-01

47

In situ tooth replica custom implant: rationale, material, and technique.  

Science.gov (United States)

This study introduced a new concept of an in situ, custom-made, tooth replica dental implant. It was obtained by injecting a self-set, nonresorbable polymer type bone graft substitute into the tooth socket after extraction. Based on its cited properties, new composite bone cement Cortoss was suggested. The properties were reviewed and evaluated. The technique of application was described with a simulation model presented that appeared simple. Apparently, immediate duplication of tooth anatomy was achieved; thus, the concept might have the potentials of spontaneous adaptation and stabilization, preservation of alveolar bone, increasing implant-bone surface area, better load distribution, and bone stimulation. Modifications were also described to manage cases of resorbed alveolar bone as well as long-standing extracted teeth. Investigations were still required to assess the performance of the material and if modifications would be needed. PMID:20545544

Ghuneim, Wael Aly

2010-01-01

48

Factors that affect individual tooth prognosis and choices in contemporary treatment planning.  

Science.gov (United States)

A clinician evaluates a tooth for its quality of health. Once accomplished an estimate of longevity and survival is estimated. With current knowledge about the survival and success of implants a decision is made as to whether to extract or to treat and maintain the tooth. Questions and doubts abound in the decision making process in regards to the prognosis of an individual tooth. Unfortunately in dentistry, as in all biologic sciences, there are no straightforward answers to questions. This article will attempt to review the literature in this area to aid the practitioner in the decision making process with regards to the compromised tooth. The article will focus on the single tooth or implant restoration. Other factors such as the strategic value of a tooth and financial limitations in relation to long-term prognosis will also be discussed. PMID:17255985

Mordohai, N; Reshad, M; Jivraj, S; Chee, W

2007-01-27

49

Processo de reparo em feridas de extração dentária em camundongos tratados com o complexo Symphytum officinale e Calendula officinallis / Process of repair in tooth extraction sores in treated mice with Symphytum officinale and Calendula officinallis compound  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Medicamentos homeopáticos como o Symphytum officinalle e a Calendula officinallis são dotados de propriedades anti-sépticas, antiinflamatória, cicatrizantes e também agem como promotores da consolidação de fraturas ósseas. Neste trabalho, uniram-se esses dois medicamentos similares em um complexo pa [...] ra verificar o seu efeito no reparo em feridas de extração dentária em camundongos. O complexo Symphytum officinalle e Calendula officinallis nas potências de 6CH e 3CH, respectivamente, foi ministrado por via oral ao grupo tratado durante 5 dias antes e após a extração do incisivo superior direito. No grupo controle, administraram-se 5ml de álcool etílico a 70% diluídos em 30 ml de soro fisiológico. Após a proservação, os animais foram sacrificados, a maxila direita separada da esquerda, fixada e processada para inclusão em parafina. Após a microtomia, os cortes obtidos foram corados pela H/E. A análise histológica mostrou que, tanto no grupo controle como no tratado, o alvéolo dentário estava preenchido por tecido de granulação e tecido ósseo neoformado, com graus variáveis de maturação, rico em osteócitos. No entanto, nos animais tratados, o processo de reparo em feridas após extração dentária do incisivo superior direito mostrou um avanço progressivo de neoformação óssea mais acentuado quando comparado ao grupo controle, em tempos equivalentes. Estes resultados enfatizam as propriedades biológicas do complexo Symphytum officinalle e Calendula officinallis e sua possível utilização como recurso terapêutico na Odontologia. Abstract in english Homeopathic medicines as Symphytum officinale and Calendula officinallis are endowed with antiseptic, antiphlogistic and cicatrizant properties and promoter of the consolidation of bone fracture. This research combined these two similar medicines in a compound to examine its action in the repair of [...] tooth extraction sores in mice. The compound Symphytum offic. and Calendula offic. at the respective potencys of 6CH and 3CH was orally administered to the treated group during 5 days before and after the extraction of the rigth upper incisor. To the control group were administered 5 ml of ethylic alchol 70% diluted in 30 ml of physiologic serum. After a period of expectation, the animals were sacrificed, the right maxila was separated of the left maxila, this was fixed and the laboratories techniques were realized for inclusion in paraffin. After that, the piece was cut in the microtome, and the laminas were dyed by H/E. The analysis showed that the control and treated group exhibited the dental alveolus fulfilled with granulation tissue and neoformed bone tissue with variable degrees of maturation, abundant in osteocites. However, at the treated animal the healing process of the sore after the extraction of the rigth upper incisor showed a bone neoformation very pronounced when compared with the control group at equivalent times. Those results showed the biological properties of the compound Symphytum offic. and Calendula offic. and its utilization as a therapeutical help in Odontology.

Eleny, BALDUCCI-ROSLINDO; Karina Gonzales, SILVÉRIO; Daniela Mercaldi, MALAGOLI.

50

TNF signalling in tooth development.  

Science.gov (United States)

Mammalian tooth development has served as an excellent model system to investigate the intricate, interactive mechanisms of patterning, morphogenesis and cytodifferentiation during organogenesis. Teeth develop from interactions between epithelium and neural crest-derived (ecto)mesenchyme that are largely mediated by ligand-receptor signalling. It is well-established that signalling molecules of the Bmp, Fgf, Wnt and Hedgehog families, are involved at multiple stages of tooth development. Recently, however, a specific role for molecules belonging to the TNF-family of ligands in tooth morphogenesis has been identified, suggesting that this pathway, acting to activate NF-kappaB, has played an important role in the development and evolution of tooth number and shape. PMID:15380242

Ohazama, Atsushi; Sharpe, Paul T

2004-10-01

51

Nasal displacement of a tooth root in a dog.  

Science.gov (United States)

A ten-year-old miniature Dachshund dog was presented for chronic paroxysmal sneezing and unilateral nasal discharge. Extraction of the maxillary right fourth premolar tooth had been performed 2-weeks prior to the onset of clinical signs. Multiple diagnostic modalities were used to confirm the diagnosis and determine that the etiology was a nasally displaced mesiopalatal tooth root. A limited lateral rhinotomy was performed to remove the root. Postoperative examination 1-month following surgery indicated resolution of the clinical signs and uncomplicated healing of the surgery site. Oral examination indicated normal healing of the surgery site with continued absence of clinical signs 6-months after treatment. PMID:15765946

Taylor, Travis N; Smith, Mark M; Snyder, Laura

2004-12-01

52

Efecto In Vitro de las Bebidas Refrescantes sobre la Mineralización de la Superficie del Esmalte Dentario de Piezas Permanentes Extraídas / In Vitro Effect of Refreshing Drinks on the Mineralization of Tooth Enamel Surface in Extracted Permanent Dental Pieces  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish El objetivo de este estudio fue determinar el efecto de las bebidas refrescantes sobre la mineralización de la superficie del esmalte de piezas dentarias permanentes extraídas. Para esto se realizó un estudio experimental donde la muestra correspondió a 50 cortes de premolares permanentes extraídos [...] en estado íntegro, estos fueron distribuidos en tres grupos de estudio mediante asignación aleatoria: bebidas gaseosas, jugos y néctares, y aguas minerales purificadas y saborizadas más un grupo control. Los dientes fueron lavados y almacenados en saliva artificial a 4°C. A todos los cortes dentarios se les midió la mineralización con el equipo Diagnodent 2095 (Kavo®) antes de iniciar la exposición, la cual correspondió a un minuto en el tipo de bebida según grupo, seguido por tres minutos en saliva artificial, ciclo que se repitió cinco veces en un tiempo de 20 minutos. Este procedimiento se realizó una vez al día, por un mes y para cada día se utilizaron nuevas bebidas refrescantes. Una vez finalizado se volvió a medir la mineralización para luego realizar las comparaciones entre grupos. El grupo de bebidas gaseosas provocó una mayor desmineralización en la superficie del esmalte dentario (p=0,000), seguido del grupo de jugos y néctares (p=0,000). El grupo de aguas minerales saborizadas y purificadas no provocaron efectos sobre la mineralización de la superficie del esmalte. Por lo tanto, sólo el grupo de gaseosas y jugos provocaron un efecto desmineralizador en la superficie del esmalte de las piezas dentarias, siendo la Coca-cola® la que produjo mayor efecto seguido de la Coca-cola light® y luego el Kapo®. Abstract in english The aim of this study was to determine the effect of refreshing drinks on the mineralization of tooth enamel surface in extracted permanent dental pieces. For this an experimental study was conducted where the sample was composed by 50 permanent premolars extracted as an entire piece. These pieces w [...] ere randomly distributed in three study groups: soft drinks, juices and nectars, and purified and flavored mineral waters, in addition to a control group. The teeth were carefully washed and stored in artificial saliva at 4 C. Before starting the exposure to refreshing drinks, all dental slices were tested in order to measure their baseline mineralization using the Diagnodent 2095 equipment (Kavo®). The exposition consisted in one minute of contact with the drink corresponding to each group, followed of three minutes in artificial saliva. This cycle was repeated 5 times in 20 minutes time. This procedure was carried out once daily, for one month, and every day new refreshing drinks were used. Once the assay finished, the premolar mineralization was measured again, in order to make comparisons between groups. The soft drinks group caused the highest demineralization on the teeth enamel surface (p=0.000), followed by the juices and nectars group (p=0.000). In the purified and flavored mineral waters group, no effects were found on the mineralization of the enamel surface. A demineralizing effect on the enamel surface of dental pieces was observed only in the groups of soft drinks and juices, where Coca-Cola® caused the highest effect, followed by Coca-Cola light® and then Kapo®.

Ximena, Moreno Ruiz; Carmen Gloria, Narváez Carrasco; Verónica, Bittner Schmidt.

2011-08-01

53

Efecto In Vitro de las Bebidas Refrescantes sobre la Mineralización de la Superficie del Esmalte Dentario de Piezas Permanentes Extraídas / In Vitro Effect of Refreshing Drinks on the Mineralization of Tooth Enamel Surface in Extracted Permanent Dental Pieces  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish El objetivo de este estudio fue determinar el efecto de las bebidas refrescantes sobre la mineralización de la superficie del esmalte de piezas dentarias permanentes extraídas. Para esto se realizó un estudio experimental donde la muestra correspondió a 50 cortes de premolares permanentes extraídos [...] en estado íntegro, estos fueron distribuidos en tres grupos de estudio mediante asignación aleatoria: bebidas gaseosas, jugos y néctares, y aguas minerales purificadas y saborizadas más un grupo control. Los dientes fueron lavados y almacenados en saliva artificial a 4°C. A todos los cortes dentarios se les midió la mineralización con el equipo Diagnodent 2095 (Kavo®) antes de iniciar la exposición, la cual correspondió a un minuto en el tipo de bebida según grupo, seguido por tres minutos en saliva artificial, ciclo que se repitió cinco veces en un tiempo de 20 minutos. Este procedimiento se realizó una vez al día, por un mes y para cada día se utilizaron nuevas bebidas refrescantes. Una vez finalizado se volvió a medir la mineralización para luego realizar las comparaciones entre grupos. El grupo de bebidas gaseosas provocó una mayor desmineralización en la superficie del esmalte dentario (p=0,000), seguido del grupo de jugos y néctares (p=0,000). El grupo de aguas minerales saborizadas y purificadas no provocaron efectos sobre la mineralización de la superficie del esmalte. Por lo tanto, sólo el grupo de gaseosas y jugos provocaron un efecto desmineralizador en la superficie del esmalte de las piezas dentarias, siendo la Coca-cola® la que produjo mayor efecto seguido de la Coca-cola light® y luego el Kapo®. Abstract in english The aim of this study was to determine the effect of refreshing drinks on the mineralization of tooth enamel surface in extracted permanent dental pieces. For this an experimental study was conducted where the sample was composed by 50 permanent premolars extracted as an entire piece. These pieces w [...] ere randomly distributed in three study groups: soft drinks, juices and nectars, and purified and flavored mineral waters, in addition to a control group. The teeth were carefully washed and stored in artificial saliva at 4 C. Before starting the exposure to refreshing drinks, all dental slices were tested in order to measure their baseline mineralization using the Diagnodent 2095 equipment (Kavo®). The exposition consisted in one minute of contact with the drink corresponding to each group, followed of three minutes in artificial saliva. This cycle was repeated 5 times in 20 minutes time. This procedure was carried out once daily, for one month, and every day new refreshing drinks were used. Once the assay finished, the premolar mineralization was measured again, in order to make comparisons between groups. The soft drinks group caused the highest demineralization on the teeth enamel surface (p=0.000), followed by the juices and nectars group (p=0.000). In the purified and flavored mineral waters group, no effects were found on the mineralization of the enamel surface. A demineralizing effect on the enamel surface of dental pieces was observed only in the groups of soft drinks and juices, where Coca-Cola® caused the highest effect, followed by Coca-Cola light® and then Kapo®.

Ximena, Moreno Ruiz; Carmen Gloria, Narváez Carrasco; Verónica, Bittner Schmidt.

54

[Fundamental and practical study for DNA analysis using tooth as a source of DNA].  

Science.gov (United States)

Degree of degradation and the yield of DNA extracted from dental pulp tissues were examined on the tooth samples (n = 50) stored at room temperature and the method of DNA extraction from tooth hard tissues was also investigated. The DNA samples obtained were also applied to forensic odontological material examination including DNA fingerprinting using a probe Myo and VNTR (variable number of tandem repeat) analysis in D4S43 locus by PCR. The amount of DNA obtained from the dental pulp tissue of a single tooth varied approximately from 3 to 40 micrograms. In most cases, high molecular weight DNA was still present in samples stored at room temperature for at least 336 days. When the dental pulp tissue samples were less than 5 mg in weight, the amount DNA extracted was usually less than 10 micrograms, however when the samples were more than 5 mg in weight, the amount of DNA extracted was more than 10 micrograms. No correlation was observed between the storage period of the tooth samples and the DNA extraction ratio (the amount of extracted DNA weight, micrograms/pulp weight, mg). The efficiency of DNA extraction from tooth hard tissues was investigated under different conditions using 0.005 M and 0.5 M EDTA solutions for decalcification. DNA was efficiently extracted from the tooth samples which were decalcified for one week without changing the 0.5 M EDTA solution or by changing the solution once within a week. Rapid decalcification using formic acid buffer was not suitable for DNA extraction from tooth hard tissues. Southern blot hybridization of DNA samples extracted from pulp tissues using Myo probe gave multiple bands. Finger print patterns obtained from DNA recovered from dental pulp and tooth hard tissues samples were identical, however, the number of hybridizing bands obtained from tooth hard tissues was less than that obtained from blood and dental pulp tissues. The D4S43 typing using DNA recovered from blood stains, dental pulp tissues and tooth hard tissues of the same individuals was in agreement with each other and the 184bp fragment was efficiently amplified in all the samples tested. The DNA obtained from dental pulp tissues usually contains high molecular weight DNA and was suitable for multilocus probe and PCR analysis. However, the DNA obtained from tooth hard tissues was suitable only for PCR analysis. PMID:7723194

Hanaoka, Y; Inoue, M; Tsai, T H; Minaguchi, K

1995-02-01

55

Restauración inmediata de un implante único post-extracción con presencia de una lesión radicular lateral / Immediate restoration of a single implant placed after tooth extraction with lateral root lesion  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish La perdida de un diente en la zona estética anterior y su reemplazo con una restauración implanto soportada representa uno de los mayores desafíos estéticos y funciónales en el campo de la Implantología moderna.La evidencia actual respalda la provisionalización inmediata de un implante después de su [...] inserción con tasas de éxito comparables con las de los protocolos tradicionales utilizados recientemente. Siegenthaler y col, concluyeron que para aquellos implantes donde se alcanzó estabilidad primaria, la colocación de implantes inmediatos en alvéolos postextracción que presentaban lesiones periapicales no conllevó a un aumento en la tasa de complicaciones y resultó en una integración igualmente favorable en comparación con el grupo control. La adecuada selección del caso para este tipo de protocolos es fundamental y debe estar regido por una filosofía clara de Preservación. La preservación de las estructuras orales existentes en el área a intervenir exige un enfoque terapéutico netamente conservador que favorezca un resultado final favorable y exitoso. La paciente tratada es una de 40 años de edad que acude al postgrado de rehabilitación oral de la Universidad CES de Medellín, Colombia cuyo motivo de consulta fue "Para revisión recomendada por periodoncia" según sus propias palabras. Al momento del examen clínico intraoral se observó encía edematizada a nivel de #11 con profundad al sondaje de 10 mm en DP sospechando una fractura vertical que se corroboró con el análisis de la radiografía periapical. Se le planteó claramente a la paciente las distintas opciones de tratamiento por la pérdida del incisivo central superior con las posibles complicaciones y riesgos que se podrían presentar. La paciente aceptó la opción del implante inmediato postextracción con provisionalización y procedió a firmar el consentimiento informado de la historia clínica. Conclusiones: La provisionalización inmediata del implante brinda beneficios adicionales para la integración de los tejidos blandos, ofreciendo unos resultados estéticos de alta calidad. La colocación de implantes inmediatos en alvéolos con procesos infecciosos periapicales tiene un porcentaje de éxito prometedor a corto plazo. Abstract in english The lost of an anterior tooth and it replacement with a retained implant restoration is one of the mayor functional and aesthetic challenges in modern implantogy. Actual Evidence support that immediate implant provisionalization compare with the traditional protocols have similar results in success [...] rates. Siegenthaler y col conclude that in situations when the primary stabilization is obtained, the implant placement in fresh sockets with cronical periapical lesions have similar results versus control group. Carefull must be taken in the case selection for this modern protocol and should be done under the preservation philosophy. The integrity of remaining bone structures and soft tissue is the main goal for the success of this technique. Female patient, 40 years old, who attended the program of oral rehabilitation at the University of CES Medellin, Colombia, whose reason for consultation was "To review recommended by periodontics" in his own words. At the time of clinical examination intraoral gum edema was observed at # 11 with probing 10 mm in DP suspecting a vertical fracture who was corroborated with the analysis of the periapical X-ray. The different treatment options were stated clearly to the patient for the loss of the maxillary central incisor with the possible complications and risks that could arise. The patient agreed to the immediate post-extraction implant option with temporization and proceeded to sign the informed consent of the medical record. Conclusions: The placement of implants immediate with infectious processes periapicals has a success rate in the short term very promising. The immediate provisionalization implant provides additional benefits for the integration of soft tissues

José Raúl, Blanco; Felix Alejandro, Mejía; Luis Felipe, Restrepo.

56

Restauración inmediata de un implante único post-extracción con presencia de una lesión radicular lateral / Immediate restoration of a single implant placed after tooth extraction with lateral root lesion  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish La perdida de un diente en la zona estética anterior y su reemplazo con una restauración implanto soportada representa uno de los mayores desafíos estéticos y funciónales en el campo de la Implantología moderna.La evidencia actual respalda la provisionalización inmediata de un implante después de su [...] inserción con tasas de éxito comparables con las de los protocolos tradicionales utilizados recientemente. Siegenthaler y col, concluyeron que para aquellos implantes donde se alcanzó estabilidad primaria, la colocación de implantes inmediatos en alvéolos postextracción que presentaban lesiones periapicales no conllevó a un aumento en la tasa de complicaciones y resultó en una integración igualmente favorable en comparación con el grupo control. La adecuada selección del caso para este tipo de protocolos es fundamental y debe estar regido por una filosofía clara de Preservación. La preservación de las estructuras orales existentes en el área a intervenir exige un enfoque terapéutico netamente conservador que favorezca un resultado final favorable y exitoso. La paciente tratada es una de 40 años de edad que acude al postgrado de rehabilitación oral de la Universidad CES de Medellín, Colombia cuyo motivo de consulta fue "Para revisión recomendada por periodoncia" según sus propias palabras. Al momento del examen clínico intraoral se observó encía edematizada a nivel de #11 con profundad al sondaje de 10 mm en DP sospechando una fractura vertical que se corroboró con el análisis de la radiografía periapical. Se le planteó claramente a la paciente las distintas opciones de tratamiento por la pérdida del incisivo central superior con las posibles complicaciones y riesgos que se podrían presentar. La paciente aceptó la opción del implante inmediato postextracción con provisionalización y procedió a firmar el consentimiento informado de la historia clínica. Conclusiones: La provisionalización inmediata del implante brinda beneficios adicionales para la integración de los tejidos blandos, ofreciendo unos resultados estéticos de alta calidad. La colocación de implantes inmediatos en alvéolos con procesos infecciosos periapicales tiene un porcentaje de éxito prometedor a corto plazo. Abstract in english The lost of an anterior tooth and it replacement with a retained implant restoration is one of the mayor functional and aesthetic challenges in modern implantogy. Actual Evidence support that immediate implant provisionalization compare with the traditional protocols have similar results in success [...] rates. Siegenthaler y col conclude that in situations when the primary stabilization is obtained, the implant placement in fresh sockets with cronical periapical lesions have similar results versus control group. Carefull must be taken in the case selection for this modern protocol and should be done under the preservation philosophy. The integrity of remaining bone structures and soft tissue is the main goal for the success of this technique. Female patient, 40 years old, who attended the program of oral rehabilitation at the University of CES Medellin, Colombia, whose reason for consultation was "To review recommended by periodontics" in his own words. At the time of clinical examination intraoral gum edema was observed at # 11 with probing 10 mm in DP suspecting a vertical fracture who was corroborated with the analysis of the periapical X-ray. The different treatment options were stated clearly to the patient for the loss of the maxillary central incisor with the possible complications and risks that could arise. The patient agreed to the immediate post-extraction implant option with temporization and proceeded to sign the informed consent of the medical record. Conclusions: The placement of implants immediate with infectious processes periapicals has a success rate in the short term very promising. The immediate provisionalization implant provides additional benefits for the integration of soft tissues

José Raúl, Blanco; Felix Alejandro, Mejía; Luis Felipe, Restrepo.

2013-01-01

57

On gear tooth stiffness evaluation  

DEFF Research Database (Denmark)

The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffnesses of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact width is constant. © 2014 Elsevier Ltd. All rights reserved.

Pedersen, Niels Leergaard; JØrgensen, Martin Felix

2014-01-01

58

21 CFR 872.3920 - Porcelain tooth.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Porcelain tooth. 872.3920 Section 872.3920 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3920 Porcelain tooth. (a)...

2010-04-01

59

Stem cells for tooth engineering.  

Science.gov (United States)

Tooth development results from sequential and reciprocal interactions between the oral epithelium and the underlying neural crest-derived mesenchyme. The generation of dental structures and/or entire teeth in the laboratory depends upon the manipulation of stem cells and requires a synergy of all cellular and molecular events that finally lead to the formation of tooth-specific hard tissues, dentin and enamel. Although mesenchymal stem cells from different origins have been extensively studied in their capacity to form dentin in vitro, information is not yet available concerning the use of epithelial stem cells. The odontogenic potential resides in the oral epithelium and thus epithelial stem cells are necessary for both the initiation of tooth formation and enamel matrix production. This review focuses on the different sources of stem cells that have been used for making teeth in vitro and their relative efficiency. Embryonic, post-natal or even adult stem cells were assessed and proved to possess an enormous regenerative potential, but their application in dental practice is still problematic and limited due to various parameters that are not yet under control such as the high risk of rejection, cell behaviour, long tooth eruption period, appropriate crown morphology and suitable colour. Nevertheless, the development of biological approaches for dental reconstruction using stem cells is promising and remains one of the greatest challenges in the dental field for the years to come. PMID:18671204

Bluteau, G; Luder, H U; De Bari, C; Mitsiadis, T A

2008-01-01

60

Charcot-Marie-Tooth Disease  

Science.gov (United States)

Charcot-Marie-Tooth disease (CMT) is a group of genetic nerve disorders. It is named after the three doctors who first identified it. ... a nerve biopsy. There is no cure. The disease can be so mild you don't realize ...

 
 
 
 
61

Erosive tooth wear in children.  

Science.gov (United States)

Erosive tooth wear in children is a common condition. Besides the anatomical differences between deciduous and permanent teeth, additional histological differences may influence their susceptibility to dissolution. Considering laboratory studies alone, it is not clear whether deciduous teeth are more liable to erosive wear than permanent teeth. However, results from epidemiological studies imply that the primary dentition is less wear resistant than permanent teeth, possibly due to the overlapping of erosion with mechanical forces (like attrition or abrasion). Although low severity of tooth wear in children does not cause a significant impact on their quality of life, early erosive damage to their permanent teeth may compromise their dentition for their entire lifetime and require extensive restorative procedures. Therefore, early diagnosis of erosive wear and adequate preventive measures are important. Knowledge on the aetiological factors of erosive wear is a prerequisite for preventive strategies. Like in adults, extrinsic and intrinsic factors, or a combination of them, are possible reasons for erosive tooth wear in children and adolescents. Several factors directly related to erosive tooth wear in children are presently discussed, such as socio-economic aspects, gastroesophageal reflux or vomiting, and intake of some medicaments, as well as behavioural factors such as unusual eating and drinking habits. Additionally, frequent and excessive consumption of erosive foodstuffs and drinks are of importance. PMID:24993274

Carvalho, Thiago S; Lussi, Adrian; Jaeggi, Thomas; Gambon, Dein L

2014-01-01

62

Successful immediate autotransplantation of tooth with incomplete root formation: case report.  

Science.gov (United States)

This case report presents successful immediate mandibular third molar autotransplantation to replace the nonrestorable mandibular first molar. In this case, after the extraction of the nonrestorable tooth, the donor molar with incomplete root formation was autotransplanted into the recipient site after the atraumatic extraction. A long-term follow-up of 2 years revealed that the tooth was fixed in its socket without residual inflammation, masticatory function was satisfactory and without discomfort; the tooth was not mobile, no pathologic condition was apparent radiographically, the lamina dura appeared normal and the tooth showed radiographic evidence of root growth, and pulpal regeneration and the depth of the pocket, gingival contour, and gingival color were all normal. The purpose of this case report is to demonstrate the clinical application of autotransplantation as a future option of permanent restoration without implants, orthodontic space closure, or partial denture. PMID:22762917

Kumar, Rahul; Khambete, Neha; Priya, Ekta

2013-05-01

63

Immediate Implant in Management of Anterior Missing Tooth  

Directory of Open Access Journals (Sweden)

Full Text Available Immediate implant placement after extraction has become a favored treatment protocol with many clinicians worldwide. There are many advantages to this protocol, amongst them; shortened treatment time, placement of the implant in sound bone that constitutes the socket wall, placement trajectory guidance by the socket and preservation of bone volume. This case report describes the management of an anterior missing tooth using immediate implant. The result was good, which further validate the use of this technique for suitable patient management.

Harinath Reddy S

2010-04-01

64

Fluoridation and tooth wear in Irish adults.  

LENUS (Irish Health Repository)

The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000\\/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

Burke, F M

2010-10-01

65

Charcot-Marie-Tooth disease.  

LENUS (Irish Health Repository)

Charcot-Marie-Tooth (CMT) disease is the commonest inherited neuromuscular disorder affecting at least 1 in 2,500. Over the last two decades, there have been rapid advances in understanding the molecular basis for many forms of CMT with more than 30 causative genes now described. This has made obtaining an accurate genetic diagnosis possible but at times challenging for clinicians. This review aims to provide a simple, pragmatic approach to diagnosing CMT from a clinician\\'s perspective.

Reilly, Mary M

2011-03-01

66

Prosthetic clone and natural human tooth comparison by speckle interferometry  

Science.gov (United States)

New trends in dental prosthodontic interventions tend to preserve the maximum of "body" structure. With the evolution of CAD-CAM techniques, it is now possible to measure "in mouth" the remaining dental tissues. The prosthetic crown is then designed using this shape on which it will be glued on, and also by taking into account the contact surface of the opposite jaw tooth. Several theories discuss on the glue thickness and formulation, but also on the way to evolve to a more biocompatible crown and also new biomechanical concepts. In order to validate these new concepts and materials, and to study the mechanical properties and mechanical integrity of the prosthesis, high resolution optical measurements of the deformations of the glue and the crown are needed. Samples are two intact premolars extracted for orthodontics reasons. The reference sample has no modifications on the tooth while the second sample tooth is shaped to receive a feldspathic ceramic monoblock crown which will be glued. This crown was manufactured with a chairside CAD-CAM system from an intra-oral optical print. The software allows to realize a nearly perfect clone of the reference sample. The necessary space for the glue is also entered with ideal values. This duplication process yields to obtain two samples with identical anatomy for further processing. The glue joint thickness can also be modified if required. The purpose is to compare the behaviour of a natural tooth and its prosthetic clone manufactured with "biomechanical" concepts. Vertical cut samples have been used to deal with planar object observation, and also to look "inside" the tooth. We have developed a complete apparatus enabling the study of the compressive mechanical behaviour of the concerned tooth by speckle interferometry. Because in plane displacements are of great interest for orthodontic measurements1, an optical fiber in-plane sensitive interferometer has been designed. The fibers are wrapped around piezoelectric transducers to perform "4-buckets" phase shifting leading to phase variations during the compression test. In-plane displacement fields from speckle interferometry already showed very interesting data concerning the mechanical behaviour of teeth: the dentine-enamel junction (DEJ) and the glue junction have been shown including their interfacing function. Mechanical action of the tooth surrounding medium will also be discussed.

Slangen, Pierre; Corn, Stephane; Fages, Michel; Raynal, Jacques; Cuisinier, Frederic J. G.

2010-09-01

67

[The possibility of tooth regenerative therapy].  

Science.gov (United States)

Teeth develop from the sequential and reciprocal interactions between the oral epithelium and neural crest-derived mesenchyme. Recently, it has been reported that many factors such as Msx1, Pax9, Lef1, Bmp, Fgf, Wnt, Shh and Eda play a critical role in tooth development. It is expected that the further accumulation of evidence involved in mechanisms of tooth development and stem cell biology could lead to the development of tooth regenerative therapy based on this biological evidence. PMID:15995301

Ohazama, Atsushi

2005-07-01

68

Molecular Genetics of Supernumerary Tooth Formation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhib...

Wang, Xiu-ping; Fan, Jiabing

2011-01-01

69

Medication-related tooth discoloration: a review.  

Science.gov (United States)

Tooth discoloration is a common problem for which patients seek dental care. Various medications can directly or indirectly result in tooth discoloration. As clinicians, it is our responsibility to know these therapeutic drugs which can cause tooth discoloration and educate our fellow colleagues to take necessary precautions when prescribing these medications. Therefore, the objective of this paper is to give an overview of the various medications that can be linked to tooth discoloration and to suggest the precautionary measures that can be taken to avoid or minimize it. Clinical Relevance: Dental discoloration potential of medications always needs to be considered before prescribing them. PMID:25073226

Thomas, Manuel S; Denny, Ceena

2014-06-01

70

Esthesioneuroblastoma presenting as tooth pain.  

Science.gov (United States)

Esthesioneuroblastoma, also called olfactory neuroblastoma, is a rare malignant tumor originating in the olfactory epithelium in the upper nasal cavity with intracranial extension and may also be associated with secondary sinus diseases. Esthesioneuroblastoma has been observed to cause death by distant metastasis or by invasion through the cribriform plate and secondary meningitis. It usually produces nasal obstruction, epistaxis and less commonly anosmia, headache and pain. We report a case of esthesioneuroblastoma in a 50-year-old female who reported with tooth pain as a presenting symptom. PMID:25364164

Devi, Parvathi; Bhavle, Radhika; Aggarwal, Avanti; Walia, Cherry

2014-09-01

71

Genetics Home Reference: Charcot-Marie-Tooth disease  

Science.gov (United States)

... gov Research studies OMIM Genetic disorder catalog Conditions > Charcot-Marie-Tooth disease On this page: Description Genetic ... names Glossary definitions Reviewed March 2013 What is Charcot-Marie-Tooth disease? Charcot-Marie-Tooth disease is ...

72

Causes of Charcot-Marie-Tooth Disease (CMT)  

Science.gov (United States)

... Marie-Tooth Disease (CMT) Causes/Inheritance Causes of Charcot-Marie-Tooth disease (CMT) Peripheral nerves control movement ... More than 30 genes have been implicated in Charcot-Marie-Tooth disease (CMT). In different types of ...

73

21 CFR 872.3200 - Resin tooth bonding agent.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Resin tooth bonding agent. 872.3200 Section...DEVICES Prosthetic Devices § 872.3200 Resin tooth bonding agent. (a) Identification. A resin tooth bonding agent is a device...

2010-04-01

74

21 CFR 872.3690 - Tooth shade resin material.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Tooth shade resin material. 872.3690 Section 872.3690...Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of...

2010-04-01

75

Restoration of the maxillary anterior tooth using immediate implantation with simultaneous ridge augmentation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Atrophy is most severe during the first month of post-extraction in the anterior maxilla with the degree of horizontal bone resorption being nearly twice as high as that of vertical bone resorption. The loss of the buccal alveolar plate following tooth extraction may lead to palatal implant positioning of the implants. Thus, immediate or early implant placement in the extraction socket has been suggested, because it would reduce the time period and the number of surgical intervention and yiel...

Park Jun-Beom

2010-01-01

76

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... at Risk for Early Childhood Tooth Decay? Temporomandibular Joint Disorder Learn what those dental words mean. The Life of a Tooth games Home | InfoBites | Find a Dentist | Your Family's Oral Health | Newsroom | RSS About AGD | Contact AGD | ...

77

Ion channels, channelopathies, and tooth formation.  

Science.gov (United States)

The biological functions of ion channels in tooth development vary according to the nature of their gating, the species of ions passing through those gates, the number of gates, localization of channels, tissue expressing the channel, and interactions between cells and microenvironment. Ion channels feature unique and specific ion flux in ameloblasts, odontoblasts, and other tooth-specific cell lineages. Both enamel and dentin have active chemical systems orchestrating a variety of ion exchanges and demineralization and remineralization processes in a stage-dependent manner. An important role for ion channels is to regulate and maintain the calcium and pH homeostasis that are critical for proper enamel and dentin biomineralization. Specific functions of chloride channels, TRPVs, calcium channels, potassium channels, and solute carrier superfamily members in tooth formation have been gradually clarified in recent years. Mutations in these ion channels or transporters often result in disastrous changes in tooth development. The channelopathies of tooth include altered eruption (CLCN7, KCNJ2, TRPV3), root dysplasia (CLCN7, KCNJ2), amelogenesis imperfecta (KCNJ1, CFTR, AE2, CACNA1C, GJA1), dentin dysplasia (CLCN5), small teeth (CACNA1C, GJA1), tooth agenesis (CLCN7), and other impairments. The mechanisms leading to tooth channelopathies are primarily related to pH regulation, calcium homeostasis, or other alterations of the niche for tooth eruption and development. PMID:24076519

Duan, X

2014-02-01

78

Three-dimensional computer vision for tooth restoration.  

Science.gov (United States)

If a person with carious lesions needs or requests crowns or inlays, these dental fillings have to be manufactured for each tooth and each person individually. We survey computer vision techniques which can be used to automate this process. We introduce three particular applications which are concerned with the reconstruction of surface information. The first one aims at building up a database of normalized depth images of posterior teeth and at extracting characteristic features from these images. In the second application, a given occlusal surface of a posterior tooth with a prepared cavity is digitally reconstructed using an intact model tooth from a given database. The calculated surface data can then be used for automatic milling of a dental prosthesis, e.g. from a preshaped ceramic block. In the third application a hand-made provisoric wax inlay or crown can be digitally scanned by a laser sensor and copied three dimensionally into a different material such as ceramic. The results are converted to a format required by the computer-integrated manufacturing (CIM) system for automatic milling. PMID:10709694

Paulus, D; Wolf, M; Meller, S; Niemann, H

1999-03-01

79

A Radiographic method for determining the actual tooth length  

International Nuclear Information System (INIS)

Tooth length determination is a crucial step in endodontic treatment. Traditionally, radiographs are used to confirm working length of the root length. This study was performed to evaluate the radiographic distortion (magnification) and calculate correction coefficients for the object-film distance. Ninety-six radiographs were made of eight extracted teeth (two upper first premolars, two lower first premolars, two upper first molars, and two lower first molars) by using the 16 inch long cone paralleling techniques with 1 mm interval from 5 to 16 mm tooth-film distance. The following results obtained; 1. The least mean radiographic distortion from 5 to 16 mm tooth-film distance was 2.42 ±0.68% (the length of mesiobuccal cusp-mesial root of lower first molars), the greatest distortion was 4.74 ±1.36% (the length of mesiobuccal cusp-mesiobuccal root of upper first molars). 2. The greatest correction coefficient was 0.986 (the mesiobuccal cusp-mesial root of lower molars, the lowest one was 0.937 (the mesiobuccal cusp-mesiobuccal root of upper first molars).

80

Neural crest contribution to mammalian tooth formation.  

Science.gov (United States)

The cranial neural crest cells, which are specialized cells of neural origin, are central to the process of mammalian tooth development. They are the only source of mesenchyme able to sustain tooth development, and give rise not only to most of the dental tissues, but also to the periodontium, the surrounding tissues that hold teeth in position. Tooth organogenesis is regulated by a series of interactions between cranial neural crest cells and the oral epithelium. In the development of a tooth, the epithelium covering the inside of the developing oral cavity provides the first instructive signals. Signaling molecules secreted by the oral epithelium 1) establish large cellular fields competent to form a specific tooth shape (mono- or multicuspid) along a proximodistal axis; 2) define an oral (capable of forming teeth) and non-oral mesenchyme along a rostrocaudal axis; and 3) position the sites of future tooth development. The critical information to model tooth shape resides later in the neural crest-derived mesenchyme. Cranial neural crest cells ultimately differentiate into highly specialized cell types to produce mature dental organs. Some cranial neural crest cells located in the dental pulp, however, maintain plasticity in their developmental potential up to postnatal life, offering new prospects for regeneration of dental tissues. PMID:15269893

Miletich, Isabelle; Sharpe, Paul T

2004-06-01

 
 
 
 
81

Establishment of quantitative diagnosis about radiopacity of tooth. Measurement of dentin mineral density by CT  

International Nuclear Information System (INIS)

In measuring the dentin mineral density (DMD), X-ray absorptiometry using slices of tooth after tooth extraction (the Slice method) is used conventionally. Because it takes time and must extract a tooth, these methods are limited to usable cases. Therefore we investigated a method to measure DMD by CT scan (the CT method). Cervical dentin in the alveolar bone was measured to avoid the influence by the beam hardening effect. The area where DMD value showed a plateau was measured to avoid the influence of the partial volume effect. DMD by CT method accorded with Slice method with a difference of 1.2%. Using this CT method, a difference of DMD among kind of tooth in the same individual was measured in 16 cases without metal restoration or prosthetic appliance in Ohu University Hospital. There were a few differences in DMD and the standard deviation of a measured value was about around 1.5%. Thus, it is suggested that all kind of tooth are useful as diagnostic standard and the CT value of dentine is effective if measured using the CT method. (author)

82

Tooth fractures in canine clinical practice  

International Nuclear Information System (INIS)

Tooth fractures constitute a considerable fraction of all tooth diseases. Out of the 5,370 dogs treated during four years, 492 were presented with dental problems and 28.3 % of the latter were treated for tooth fractures. Canines were the most frequently affected teeth (38.8 %), followed by premolars (33.1 %), incisors (25.9 %), and molars (2.2 %), 55.4 % of the patients with canine and incisor fractures being large breed dogs. Fractures of premolars (mostly of 108, 208) were divided evenly irrespective of breed or body size. Nonsurgical endodontic treatment yielded good therapeutic results in most cases, but repeated treatment was necessary in some patients

83

Sports Safety: Avoiding Tooth and Mouth Injuries  

Science.gov (United States)

Sports Safety: Avoiding Tooth and Mouth Injuries A few years ago, a dental newsletter published what seemed ... the perfect dunk. In older children and adults, sports injuries are common. Dentists estimate that between 13% ...

84

Genetics And Tooth Anomalies - An Update  

Directory of Open Access Journals (Sweden)

Full Text Available Tooth development like the development of all epithelial appendages is regulated by inductive tissue interactions between epithelium and mesenchyme. Numerous genes interact, either act in conjunction or antagonize each other in odontogenesis. A number of different mesenchymal molecules and their receptors act as mediators in epithelial mesenchymal interactions. Several genes linked with early tooth positioning and developments belong to signaling pathways and have morphogenesis regulatory functions in morphogenesis of other organs. Their mutations often show pleiotropic effects beyond dental morphogenesis. In contrast, certain genes involved in enamel and dentin structures are highly specific for tooth. Mutations in these genes have been identified as causes of Amelogenesis Imperfecta (AI, Dentinogenesis Imperfecta (DI, Dentin Dysplasia (DD and anomalies in tooth number. This article focuses on genetic basis of inherited non-syndromic teeth disorders.

Aswathy Brahmanandan

2013-01-01

85

Recent approaches in tooth engineering research.  

Science.gov (United States)

Tooth absence and defects caused by various reasons are frequent events in humans. They are not life threatening but may bring about social consequences. Recent dentistry provides solutions in the form of prosthetics or dental implants; however, several complications and distinct limitations favour bioengineering of dental and periodontal structures. At least two types of cells (epithelial and mesenchymal) have to be recombined to produce a new functional tooth. Moreover, the tooth must be vascularized, innervated and properly anchored in the bone. To study these issues, different approaches have been established in both basic and applied research. In this review, recent strategies and techniques of tooth engineering are comprehensively summarized and discussed, particularly regarding manipulation using stem cells. PMID:25369337

Svandová, E; Veselá, B; K?ivánek, J; Hampl, A; Matalová, E

2014-01-01

86

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Men's Oral Health How Do I Care for My Child's Baby ... for Early Childhood Tooth Decay? Why is Oral Health Important for Men? What is a Composite Resin ( ...

87

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Men's Oral Health What is Baby Bottle Tooth Decay? How Do ... Orofacial Pain? Temporomandibular Joint Disorder Why is Oral Health Important for Men? Learn what those dental words ...

88

Dielectric response of the human tooth dentine  

Science.gov (United States)

Dielectric properties of tooth dentine can be well described by the model which was developed for the dielectric response to hydrating porous cement paste. It is shown that the normalized dielectric constant and the normalized specific conductivity are proportional to the model parameters ? and ?v, indicating the deposition of AgCl in the dentine tubules during the duration of the precipitation. The fractal dimension of the tooth dentine was determined by dielectric spectroscopy.

Leskovec, J.; Filipi?, C.; Levstik, A.

2005-07-01

89

Dielectric response of the human tooth dentine  

International Nuclear Information System (INIS)

Dielectric properties of tooth dentine can be well described by the model which was developed for the dielectric response to hydrating porous cement paste. It is shown that the normalized dielectric constant and the normalized specific conductivity are proportional to the model parameters -bar v0 and ?v, indicating the deposition of AgCl in the dentine tubules during the duration of the precipitation. The fractal dimension of the tooth dentine was determined by dielectric spectroscopy

90

Tooth in Ethmoid Sinus: A Case Report  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ectopic eruption of teeth occurs in a variety of locations.Commonly seen in palate and maxillary sinus, they have alsobeen reported in nasal cavity, orbit, mandibular condyle,coronoid process, and facial skin.Here, we report a rare case of recurrent sinusitis caused byectopic tooth in right ethmoid sinus and successful endoscopicremoval of it. The symptoms of the patient disappeared aftersurgery. Such case has not been yet reported in the Englishliterature.Ectopic tooth is an uncommon cause o...

Tayebe Kazemei; Akbar Bayat; Mahmood Shishegar

2009-01-01

91

Tooth wear: the view of the anthropologist  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Anthropologists have for many years considered human tooth wear a normal physiological phenomenon where teeth, although worn, remain functional throughout life. Wear was considered pathological only if pulpal exposure or premature tooth loss occurred. In addition, adaptive changes to the stomatognathic system in response to wear have been reported including continual eruption, the widening of the masticatory cycle, remodelling of the temporomandibular joint and the shortening of the dental ar...

Kaidonis, John A.

2008-01-01

92

External resorption presenting as an intracoronal radiolucent lesion in a pre-eruptive tooth.  

LENUS (Irish Health Repository)

A large intracoronal radiolucent lesion in an unerupted permanent molar was found during the routine assessment of a young male Caucasian prior to orthodontic treatment. The tooth was extracted. Histological examination indicated the lesion was caused by external resorption. The defect extended widely into the enamel and dentine, and was repaired in part by bone. The pulp chamber was not involved. The aetiology of these lesions is often obscure but in this case it appeared to have originated in the floor of two developmental pits on the occlusal surface of the tooth.

McNamara, C M

1997-09-01

93

Diagnosis of erosive tooth wear.  

Science.gov (United States)

The clinical diagnosis 'erosion' is made from characteristic deviations from the original anatomical tooth morphology, thus distinguishing acid-induced tissue loss from other forms of wear. Primary pathognomonic features are shallow concavities on smooth surfaces occurring coronal from the enamel-cementum junction. Problems from diagnosing occlusal surfaces and exposed dentine are discussed. Indices for recording erosive wear include morphological as well as quantitative criteria. Currently, various indices are used, each having their virtues and flaws, making the comparison of prevalence studies difficult. The Basic Erosive Wear Examination (BEWE) is described, which is intended to provide an easy tool for research as well as for use in general dental practice. The cumulative score of this index is the sum of the most severe scores obtained from all sextants and is linked to suggestions for clinical management. In addition to recording erosive lesions, the assessment of progression is important as the indication of treatment measures depends on erosion activity. A number of evaluated and sensitive methods for in vitro and in situ approaches are available, but the fundamental problem for their clinical use is the lack of reidentifiable reference areas. Tools for clinical monitoring are described. PMID:24993255

Ganss, Carolina; Lussi, Adrian

2014-01-01

94

On the mechanical properties of tooth enamel under spherical indentation.  

Science.gov (United States)

The mechanical properties of tooth enamel generally exhibit large variations, which reflect its structural and material complexity. Some key properties were evaluated under localized contact, simulating actual functioning conditions. Prominent cusps of extracted human molar teeth were polished down ?0.7mm below the cusp tip and indented by tungsten carbide balls. The internal damage was assessed after unloading from longitudinal or transverse sections. The ultimate tensile stress (UTS) was determined using a novel bilayer specimen. The damage is characterized by penny-like radial cracks driven by hoop stresses and cylindrical cracks driven along protein-rich interrod materials by shear stresses. Shallow cone cracks typical of homogeneous materials which may cause rapid tooth wear under repeat contact are thus avoided. The mean stress vs. indentation strain curve is highly nonlinear, attributable to plastic shearing of protein between and within enamel rods. This curve is also affected by damage, especially radial cracks, the onset of which depends on ball radius. Several material properties were extracted from the tests, including shear strain at the onset of ring cracks ?F (=0.14), UTS (=119MPa), toughness KC (=0.94MPam(1/2)), a crack propagation law and a constitutive response determined by trial and error with the aid of a finite-element analysis. These quantities, which are only slightly sensitive to anatomical location within the enamel region tested, facilitate a quantitative assessment of crown failure. Causes for variations in published UTS and KC values are discussed. PMID:25034644

Chai, Herzl

2014-11-01

95

Roles of Bmp4 during tooth morphogenesis and sequential tooth formation.  

Science.gov (United States)

Previous studies have suggested that Bmp4 is a key Msx1-dependent mesenchymal odontogenic signal for driving tooth morphogenesis through the bud-to-cap transition. Whereas all tooth germs were arrested at the bud stage in Msx1(-/-) mice, we show that depleting functional Bmp4 mRNAs in the tooth mesenchyme, through neural crest-specific gene inactivation in Bmp4(f/f);Wnt1Cre mice, caused mandibular molar developmental arrest at the bud stage but allowed maxillary molars and incisors to develop to mineralized teeth. We found that expression of Osr2, which encodes a zinc finger protein that antagonizes Msx1-mediated activation of odontogenic mesenchyme, was significantly upregulated in the molar tooth mesenchyme in Bmp4(f/f);Wnt1Cre embryos. Msx1 heterozygosity enhanced maxillary molar developmental defects whereas Osr2 heterozygosity partially rescued mandibular first molar morphogenesis in Bmp4(f/f);Wnt1Cre mice. Moreover, in contrast to complete lack of supernumerary tooth initiation in Msx1(-/-)Osr2(-/-) mice, Osr2(-/-)Bmp4(f/f);Wnt1Cre compound mutant mice exhibited formation and subsequent arrest of supernumerary tooth germs that correlated with downregulation of Msx1 expression in the tooth mesenchyme. In addition, we found that the Wnt inhibitors Dkk2 and Wif1 were much more abundantly expressed in the mandibular than maxillary molar mesenchyme in wild-type embryos and that Dkk2 expression was significantly upregulated in the molar mesenchyme in Bmp4(f/f);Wnt1Cre embryos, which correlated with the dramatic differences in maxillary and mandibular molar phenotypes in Bmp4(f/f);Wnt1Cre mice. Together, these data indicate that Bmp4 signaling suppresses tooth developmental inhibitors in the tooth mesenchyme, including Dkk2 and Osr2, and synergizes with Msx1 to activate mesenchymal odontogenic potential for tooth morphogenesis and sequential tooth formation. PMID:23250216

Jia, Shihai; Zhou, Jing; Gao, Yang; Baek, Jin-A; Martin, James F; Lan, Yu; Jiang, Rulang

2013-01-15

96

Locked Mouths: Tooth Loss in a Women's Prison in Northeastern Brazil  

Science.gov (United States)

Background. Prisoners, in general, exhibit unsatisfactory oral conditions, especially with regard to the large number of missing teeth and with untreated caries. The aim of this study was to assess tooth loss, use of and need for prosthetic rehabilitation, and use of dental services among inmates. A cross-sectional study involving 65 inmates was developed at the Regional Women's Prison of Campina Grande, Brazil. Data regarding sociodemographic and sentencing profile, use of dental services, dental morbidity, and self-perceived oral health impacts were investigated. Chi-square, Pearson, and Kruskal-Wallis (P < 0.05) statistical tests were used. The mean tooth loss was 11.3 teeth. Significant association between tooth loss and oral health satisfaction (P = 0.049), self-perceived need for dental prosthesis (P < 0.001), uncomfortable teeth brushing (P = 0.005), difficult speaking (P = 0.002), and difficulty in performing routine tasks (P = 0.025) was observed. It was observed that 29.2% of inmates were using some type of prosthesis, all deemed unsuitable for use, and 78.5% of inmates needed prosthetic rehabilitation. The oral health condition of the population studied was found to be poor, and prisoners showed significant tooth loss and need for dentures, with the aggravation of having tooth extraction as the major reason for seeking dental care. PMID:25121127

Rodrigues, Iris Sant' Anna Araujo; Silveira, Ingrid Thays de Melo; Pinto, Magaly Suenya de Almeida; Xavier, Alidianne Fabia Cabral; de Oliveira, Thaliny Batista Sarmento; de Paiva, Saul Martins; de Castro, Ricardo Dias; Cavalcanti, Alessandro Leite

2014-01-01

97

Evaluation of the Effect of Corticotomy on Rate of Tooth Movement and Comparison with Conventional Method  

Directory of Open Access Journals (Sweden)

Full Text Available Statement of Problem: Reduction of orthodontic therapy treatment time is considered an important goal inthe management of malocclusion in adult patients. Corticotomy- facilitated orthodontic treatment may beconsidered an intermediate therapy between orthognatic surgry and conventional orthodontics for reducing treatment time.Purpose: This study was undertaken to evaluate and compare the rate of tooth movement of upper canine following corticotomy with conventional method.Materials and Methods: Ten young adult patients, 17-25 years old was selected through sequential sampling procedure in orthodontics department of Shiraz Dental School. The patients exhibited different orthodontic problems and needed extraction of premolars. Following extraction of premolars and initial phase oforthodontic treatment, corticotomy were performed unilaterally on buccual and palatal sides of extraction areaas described by Takami. The other imoperated sides were used as control. After subsiding the resultant inflammation, the activated NiTi spring was used and measurement of the amount of tooth movement wereassessed by using Rugae as reference point. The panoramic radiographs were super imposed for evaluation of canines tipping. For analyzing the results, Kolmogorou- simirnov and t.tcst were used. Results: The rate of canine tooth movement was much greater in the corticotomy sides than the unoperated (control side (P=0.015. This was especially significant at the end of first week of tooth movement(P=0.000. Comparing the two sides, the amount of canine tipping was much lesser in corticotomy group than the control group (P=0.046. There was no significant difference concerning the anchorage loss between thetwo groups (P=0.410.Conclusion: Corticotomy procedure had a positive effect on the rate of tooth movement with less tipping of the canines comparing to conventional orthodontic treatment. To get more benefit from this procedure, it is recommended to select those patients who do not need canine alignment after premolars extraction, such asbimaxillary dento alveolar protrusions.

B. Rahsepar

2005-02-01

98

Gamma-ray dose response of ESR signals in tooth enamel of cows and mice in comparison with human teeth  

International Nuclear Information System (INIS)

The ESR dose responses of the tooth enamel samples prepared from teeth of cow and mice were examined in comparison with that of human. The samples were prepared with combined procedures of mechanical and chemical treatments of teeth. The ESR dose response was extracted from the total ESR spectra of tooth enamel samples by a specially developed matrix method. The dosimetric signal was found to be increased linearly with gamma dose for all studied tooth enamel samples. The radiation sensitivity of cow tooth enamel was found to be close to that of human teeth while that of mouse teeth was about 25% lower. The present results indicate that, having high radiation sensitivity, cow and mouse teeth can be used for retrospective radiation dosimetry in low-dose level

99

Review: extracellular matrix regulates tooth morphogenesis.  

Science.gov (United States)

Mineralized tissues are unique in that they use proteins to attract and organize calcium and phosphate ions into a structured mineral phase, thus precise knowledge of the expression and extracellular distribution of matrix proteins is very important to understand their function. Tooth development is regulated by sequential and reciprocal interactions between neural crest-derived mesenchymal cells and the oral environment. However, the precise molecular mechanisms that mediate interactions between epithelium and mesenchymal cells are not clear, although basement membrane (BM) components have been shown to play important roles in these regulatory events. In addition, the extracellular matrix layer, whose main components are laminin, collagen IV, nidogen, and sulfated proteoglycan, and the BM layer are both considered to be involved with cell proliferation and differentiation. During tooth morphogenesis, extracellular matrices are dramatically changed. Further, the BM components, laminin and collagen IV support dental epithelium; however, in the late stage, they begin the processes of enamel matrix secretion and calcification, after which the BM structure between the dental epithelium and mesenchyme disappears. In addition, tooth abnormalities associated with several kinds of human diseases that cause mutations in the extracellular matrix, as well as the molecular mechanisms of the basement membrane and enamel matrix during tooth morphogenesis, are not clearly understood. In our review, we discuss the role of the extracellular matrix, with focus on the BM and enamel matrix during tooth morphogenesis. PMID:16546825

Fukumoto, Satoshi; Yamada, Yoshihiko

2005-01-01

100

Efeito comparativo entre a dipirona sódica e a dipirona sódica associada à cafeína no controle da dor pós-exodontia / Comparative effect of sodium dipyrone and sodium dipyrone associated to caffeine to control post-tooth extraction pain  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese JUSTIFICATIVA E OBJETIVOS: O adequado controle da dor pós-operatória constitui um desafio entre as especialidades cirúrgicas, a despeito dos recentes avanços das técnicas de analgesia e dos analgésicos. A cafeína tem sido utilizada como adjuvante terapêutico para potencializar a eficácia analgésica [...] de alguns fármacos, porém ainda não existe relatos de investigação científica da associação com a dipirona sódica em dor pós-operatória em procedimentos odontológicos. Dessa forma, o objetivo deste estudo foi observar e comparar a eficácia da dipirona sódica isolada e da dipirona sódica associada à cafeína no controle da dor pós-operatória em cirurgia dental, considerando os parâmetros hemodinâmicos dos pacientes como indicador de ansiedade e de dor durante a cirurgia. MÉTODOS: Estudo cruzado e duplo encoberto incluiu 50 pacientes jovens e saudáveis (25 homens e 25 mulheres) com indicação de exodontia bilateral de terceiros molares mandibulares impactados. O lado operado, o gênero do paciente e o fármaco analgésico usado foram randomizados. Os escores obtidos pela escala analógica visual foram submetidos ao teste de Friedman (? = 0,05) para comparação das intensidades dolorosas em intervalos definidos (pré-operatório, pós-operatório imediato, 1, 2, 4 12 horas, 1, 2, 3 e 7 dias após as cirurgias) e as alterações nos parâmetros de pressão arterial e frequên­cia cardíaca foram mensurados no pré-operatório, após a injeção anestésica e no pós-operatório (teste de Friedman, ? = 0,05). RESULTADOS: Os pacientes experimentaram dor leve nos dois primeiros dias de pós-operatório e não houve diferença estatisticamente significante entre a eficácia analgésica da dipirona sódica isolada e da dipirona sódica associada à cafeína nos diferentes intervalos medidos. A maioria das alterações cardiovasculares observadas estava dentro da normalidade, considerando a ansiedade e estresse induzido pela cirurgia. CONCLUSÃO: O protocolo terapêutico proposto neste estudo não demonstrou diferença estatística significante na eficiência analgésica da dipirona sódica associada ou não a cafeína no controle da dor pós-exodontia. Abstract in english BACKGROUND AND OBJECTIVES: Adequate postoperative pain control is a challenge among surgical specialties, in spite of recent advances in analgesic techniques and analgesics. Caffeine has been used as therapeutic adjuvant to potentiate analgesic efficacy of some drugs, however there are still no scie [...] ntific investigation reports on the association with sodium dipyrone in the postoperative period of dental procedures. So, this study aimed at observing and comparing the efficacy of sodium dipyrone alone or in association with caffeine to control postoperative pain of dental procedures, considering hemodynamic parameters of patients as indicators of anxiety and pain during surgery. METHODS: This is a crossover and double-blind study involving 50 young and healthy patients (25 males and 25 females) referred for bilateral extraction of impacted mandibular third molars. Operated side, patient's gender and analgesic drug used were randomized. Visual analog scale scores were submitted to Friedman test (? = 0.05) to compare pain intensity at defined intervals (preoperative, immediate postoperative, 1, 2, 4 and 12 hours, 1, 2, 3 and 7 days after surgery). Blood pressure and heart rate were measured in the preoperative period, after anesthetic injection and in the postoperative period (Friedman test, (? = 0.05). RESULTS: Patients have referred mild pain in the first two postoperative days and there has been no statistically significant difference between the analgesic efficacy of sodium dipyrone alone or in association with caffeine in different evaluated intervals. Most cardiovascular changes were within normality, considering anxiety and stress induced by surgery. CONCLUSION: The therapeutic protocol proposed in this study has not shown statisticall

Carllini Barroso, Vicentini; Juliana Cama, Ramacciato; Rubens Gonçalves, Teixeira; Francisco Carlos, Groppo; Rogério Heládio Lopes, Motta.

2013-09-01

 
 
 
 
101

Evaluation of effect of low level laser therapy on pain during orthodontic tooth movement in human  

Directory of Open Access Journals (Sweden)

Full Text Available "nBackground and Aims: Lasers with different characteristics have been used to stimulate orthodontic tooth movements and to inhibit the pain during tooth movements. Considering the contradictory finding in this respect, the effect of low level laser therapy (LLLT was evaluated on the pain during orthodontic tooth movement. "nMaterials and Methods: In this randomized clinical trial study, 12 patients were included with extracted upper first premolars and required canine retraction into extraction site. While in both sides canines were retracted by Niti coil spring, one side was exposed to GaAlAs laser (890nm. LLLT was done on the buccal and palatal mucosa by slow movement of probe. The patients were asked about their pain on both sides 2 days after beginning of retraction. Pain measurement was evaluated with VAS. "nResults: Pain perception in LLLT side significantly decreased (P=0.007. "nConclusion: Based on the results, single irradiation of GaAlAs laser (12J energy per tooth can decrease pain perception.

Hosseini MH

2010-06-01

102

Acoustic emission analysis of tooth-composite interfacial debonding.  

Science.gov (United States)

This study detected tooth-composite interfacial debonding during composite restoration by means of acoustic emission (AE) analysis and investigated the effects of composite properties and adhesives on AE characteristics. The polymerization shrinkage, peak shrinkage rate, flexural modulus, and shrinkage stress of a methacrylate-based universal hybrid, a flowable, and a silorane-based composite were measured. Class I cavities on 49 extracted premolars were restored with 1 of the 3 composites and 1 of the following adhesives: 2 etch-and-rinse adhesives, 2 self-etch adhesives, and an adhesive for the silorane-based composite. AE analysis was done for 2,000 sec during light-curing. The silorane-based composite exhibited the lowest shrinkage (rate), the longest time to peak shrinkage rate, the lowest shrinkage stress, and the fewest AE events. AE events were detected immediately after the beginning of light-curing in most composite-adhesive combinations, but not until 40 sec after light-curing began for the silorane-based composite. AE events were concentrated at the initial stage of curing in self-etch adhesives compared with etch-and-rinse adhesives. Reducing the shrinkage (rate) of composites resulted in reduced shrinkage stress and less debonding, as evidenced by fewer AE events. AE is an effective technique for monitoring, in real time, the debonding kinetics at the tooth-composite interface. PMID:23100273

Cho, N Y; Ferracane, J L; Lee, I B

2013-01-01

103

A rat model of Charcot-Marie-Tooth disease 1A recapitulates disease variability and supplies biomarkers of axonal loss in patients.  

Science.gov (United States)

Charcot-Marie-Tooth disease is the most common inherited neuropathy and a duplication of the peripheral myelin protein 22 gene causes the most frequent subform Charcot-Marie-Tooth 1A. Patients develop a slowly progressive dysmyelinating and demyelinating peripheral neuropathy and distally pronounced muscle atrophy. The amount of axonal loss determines disease severity. Although patients share an identical monogenetic defect, the disease progression is strikingly variable and the impending disease course can not be predicted in individual patients. Despite promising experimental data, recent therapy trials have failed. Established clinical outcome measures are thought to be too insensitive to detect amelioration within trials. Surrogate biomarkers of disease severity in Charcot-Marie-Tooth 1A are thus urgently needed. Peripheral myelin protein 22 transgenic rats harbouring additional copies of the peripheral myelin protein 22 gene ('Charcot-Marie-Tooth rats'), which were kept on an outbred background mimic disease hallmarks and phenocopy the variable disease severity of patients with Charcot-Marie-Tooth 1A. Hence, we used the Charcot-Marie-Tooth rat to dissect prospective and surrogate markers of disease severity derived from sciatic nerve and skin tissue messenger RNA extracts. Gene set enrichment analysis of sciatic nerve transcriptomes revealed that dysregulation of lipid metabolism associated genes such as peroxisome proliferator-activated receptor gamma constitutes a modifier of present and future disease severity. Importantly, we directly validated disease severity markers from the Charcot-Marie-Tooth rats in 46 patients with Charcot-Marie-Tooth 1A. Our data suggest that the combination of age and cutaneous messenger RNA levels of glutathione S-transferase theta 2 and cathepsin A composes a strong indicator of disease severity in patients with Charcot-Marie-Tooth 1A, as quantified by the Charcot-Marie-Tooth Neuropathy Score. This translational approach, utilizing a transgenic animal model, demonstrates that transcriptional analysis of skin biopsy is suitable to identify biomarkers of Charcot-Marie-Tooth 1A. PMID:22189569

Fledrich, Robert; Schlotter-Weigel, Beate; Schnizer, Tuuli J; Wichert, Sven P; Stassart, Ruth M; Meyer zu Hörste, Gerd; Klink, Axel; Weiss, Bernhard G; Haag, Uwe; Walter, Maggie C; Rautenstrauss, Bernd; Paulus, Walter; Rossner, Moritz J; Sereda, Michael W

2012-01-01

104

[Ectopic molar tooth in the maxillary sinus].  

Science.gov (United States)

The development of intranasal ectopic teeth is rare. Although they are more commonly seen in the palate and maxillary sinus, they can also be found in the mandibular condyle, coronoid process, and nasal cavity. A 30-year-old male patient presented with a complaint of headache. Computed tomography of the paranasal sinuses showed a bony mass in the right maxillary sinus wall, 1 cm in size. He did not have any history of maxillofacial trauma or operation. The mass was removed via a Caldwell-Luc procedure. It looked like a tooth. Histopathologic diagnosis was made as ectopic molar tooth. The patient was asymptomatic two weeks after the operation. PMID:18187979

Altun, Hüseyin; Teker, Ay?enur Meriç; Ceran, Murat; Gedikli, Orhan

2007-01-01

105

Relationship between tooth and long bone size.  

Science.gov (United States)

Canonical correlations between tooth and long bone dimensions showed a greater correlation for Anglo-Saxons and apes than for Nineteenth Century Londoners, i.e., coefficients of 0.75 for gorilla, 0.72 for chimpanzee, 0.69 for orang-utans, 0.74 for Anglo-Saxons, but 0.53 for Nineteenth Century Londoners. Although based upon limited sample sizes and limited metrical profiles of teeth and long bones, the data support the thesis that modern Europeans are under reduced selection pressure to maintain tooth size compared with apes or ancient man. PMID:860754

Lavelle, C L

1977-05-01

106

Intranasal Tooth: Report of Three Cases.  

Directory of Open Access Journals (Sweden)

Full Text Available Intranasal teeth are uncommon, with only a few reported cases in the past few decades.The clinical manifestations of an intranasal tooth are quite variable. Unilateral nasal obstructionis a common complaint, but even though nasal symptoms are present, an intranasaltooth can be an incidental finding during routine examination in patients without nasal discomfort.Although the diagnosis is not difficult to make, a complete workup that includedradiological investigations is important before any surgery is attempted. Transnasal endoscopicsurgical approaches have been described with no evidence of recurrence or complicationsin similar cases. Herein, three patients with an intranasal tooth are described, alongwith possible etiologies, potential complications, differential diagnoses and their treatments.

I-Hung Lin

2004-05-01

107

21 CFR 872.3580 - Preformed gold denture tooth.  

Science.gov (United States)

...2010-04-01 false Preformed gold denture tooth. 872.3580 Section 872.3580 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a)...

2010-04-01

108

21 CFR 872.5525 - Preformed tooth positioner.  

Science.gov (United States)

...2010-04-01 false Preformed tooth positioner. 872.5525 Section 872.5525 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5525 Preformed tooth positioner. (a)...

2010-04-01

109

21 CFR 872.3590 - Preformed plastic denture tooth.  

Science.gov (United States)

...2010-04-01 false Preformed plastic denture tooth. 872.3590 Section 872.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a)...

2010-04-01

110

About Kids' Teeth: Baby Tooth Decay is Real  

Medline Plus

Full Text Available ... – decay is mostly preventable . What Are Cavities? Causes of Decay Tooth decay begins when cavity-causing ... causing bacteria is passed to the baby. Another cause of tooth decay in babies is frequent or ...

111

Tooth Wear Prevalence and Sample Size Determination : A Pilot Study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tooth wear is the non-carious loss of tooth tissue, which results from three processes namely attrition, erosion and abrasion. These can occur in isolation or simultaneously. Very mild tooth wear is a physiological effect of aging. This study aims to estimate the prevalence of tooth wear among 16-year old Malay school children and determine a feasible sample size for further study. Fifty-five subjects were examined clinically, followed by the completion of self-administered questionnaires. Qu...

Abd Karim, Nama Bibi Saerah; Ismail, Noorliza Mastura; Naing, Lin; Ismail, Abdul Rashid

2008-01-01

112

EPR dosimetry with tooth enamel: A review  

International Nuclear Information System (INIS)

When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed.

113

Gastroesophageal reflux disease and tooth erosion.  

Science.gov (United States)

The increasing prevalence of gastroesophageal reflux disease (GERD) in children and adults, and of "silent refluxers" in particular, increases the responsibility of dentists to be alert to this potentially severe condition when observing unexplained instances of tooth erosion. Although gastroesophageal reflux is a normal physiologic occurrence, excessive gastric and duodenal regurgitation combined with a decrease in normal protective mechanisms, including an adequate production of saliva, may result in many esophageal and extraesophageal adverse conditions. Sleep-related GERD is particularly insidious as the supine position enhances the proximal migration of gastric contents, and normal saliva production is much reduced. Gastric acid will displace saliva easily from tooth surfaces, and proteolytic pepsin will remove protective dental pellicle. Though increasing evidence of associations between GERD and tooth erosion has been shown in both animal and human studies, relatively few clinical studies have been carried out under controlled trial conditions. Suspicion of an endogenous source of acid being associated with observed tooth erosion requires medical referral and management of the patient as the primary method for its prevention and control. PMID:22194748

Ranjitkar, Sarbin; Kaidonis, John A; Smales, Roger J

2012-01-01

114

Computed tomography to quantify tooth abrasion  

Science.gov (United States)

Cone-beam computed tomography, also termed digital volume tomography, has become a standard technique in dentistry, allowing for fast 3D jaw imaging including denture at moderate spatial resolution. More detailed X-ray images of restricted volumes for post-mortem studies in dental anthropology are obtained by means of micro computed tomography. The present study evaluates the impact of the pipe smoking wear on teeth morphology comparing the abraded tooth with its contra-lateral counterpart. A set of 60 teeth, loose or anchored in the jaw, from 12 dentitions have been analyzed. After the two contra-lateral teeth were scanned, one dataset has been mirrored before the two datasets were registered using affine and rigid registration algorithms. Rigid registration provides three translational and three rotational parameters to maximize the overlap of two rigid bodies. For the affine registration, three scaling factors are incorporated. Within the present investigation, affine and rigid registrations yield comparable values. The restriction to the six parameters of the rigid registration is not a limitation. The differences in size and shape between the tooth and its contra-lateral counterpart generally exhibit only a few percent in the non-abraded volume, validating that the contralateral tooth is a reasonable approximation to quantify, for example, the volume loss as the result of long-term clay pipe smoking. Therefore, this approach allows quantifying the impact of the pipe abrasion on the internal tooth morphology including root canal, dentin, and enamel volumes.

Kofmehl, Lukas; Schulz, Georg; Deyhle, Hans; Filippi, Andreas; Hotz, Gerhard; Berndt-Dagassan, Dorothea; Kramis, Simon; Beckmann, Felix; Müller, Bert

2010-09-01

115

Surgical Tooth Implants, Combats and Field.  

Science.gov (United States)

Recent studies have been concerned with the development of a high-density alumina implantable tooth root structure upon which a conventional crown can be placed. Stabilization of the implant in the socket is achieved by means of bone and the ceramic. Ging...

D. E. Niesz, M. J. O'Hara, T. D. Driskell

1972-01-01

116

Charcot-Marie-Tooth and Related Diseases  

Science.gov (United States)

... of France, and Howard Henry Tooth of the United Kingdom. Although most people have never heard of CMT, it affects some 115,000 Americans. Unlike other neurological disorders, CMT usually isn’t life-threatening, and it almost never affects the brain. ...

117

Saw-toothed fish bone ingestion: A method for propulsion  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english We describe the case of an 11-year-old girl who presented with a lump in her neck. On exploration a 4 cm saw-toothed fish bone was extracted from the soft tissue of the anterior triangle of the neck. Ingested fish bones are a common presentation in accident and emergency departments, but there are o [...] nly a small number of reports of migration through the pharynx into soft tissues. Rare complications can include oesophageal perforation, haematoma formation, retropharyngeal abscesses and recurrent infections. To the best of our knowledge this is the first reported case of migration of an ingested fish bone in Malawi.

Emily, Broadis; Wakisa, Mulwafu.

2010-05-01

118

Orthodontic tooth movement through the maxillary sinus in an adult with multiple missing teeth.  

Science.gov (United States)

This case report describes the successful orthodontic tooth movement through the maxillary sinus in an adult patient. A 41-year-old Asian woman had severe lip protrusion and multiple missing posterior teeth. Her orthodontic treatment included the extraction of 2 teeth, maximum retraction of the incisors using the extraction spaces and the existing spaces from the missing molars, and closure of all remaining spaces. Even though the treatment time was extended because of the anatomic and biologic challenges associated with moving posterior teeth over a long distance through the maxillary sinus, a successful outcome was obtained, with significant bone modeling of the maxillary sinus. The results demonstrate that a carefully selected force system can overcome the anatomic limitations of moving tooth against the cortical bone of the maxillary sinus wall in adult patients. PMID:25263152

Oh, Heesoo; Herchold, Kiri; Hannon, Stephanie; Heetland, Kelly; Ashraf, Golnaz; Nguyen, Vince; Cho, Heon Jae

2014-10-01

119

Is tooth wear in the primary dentition predictive of tooth wear in the permanent dentition? Report from a longitudinal study.  

LENUS (Irish Health Repository)

To determine the prevalence of tooth wear in the permanent dentition of a sample of 12-year-old school children and establish whether an association exists between tooth wear recorded now and tooth wear recorded in their primary dentition at age five.

Harding, M A

2010-03-01

120

Immediate esthetic crown with a facet of the extracted element.  

Science.gov (United States)

The present report describes a case of implant loading with an immediate temporary crown. The buccal crown surface was removed from the extracted tooth to obtain an aesthetically satisfactory result. After periodontal treatment, tooth 21 appeared proclined and showed Grade 3 mobility, indicating the need for its extraction. The remaining bone was imaged using computed tomography, and virtual surgical planning was performed using these results. The implant was immediately loaded postextraction into the fresh alveolus without a graft and flap procedure. The temporary tooth, which was manufactured using the extracted buccal surface, was a simple, fast, and low cost procedure that produced an excellent esthetic outcome. PMID:25202225

Di Giacomo, Giovanni de Almeida Prado; Magalhães, Amanda; Ajzen, Sergio

2014-07-01

 
 
 
 
121

Study on electron spin resonance dosimetry of dog tooth enamel  

International Nuclear Information System (INIS)

Four groups dog tooth enamel samples were irradiated with different dose by 137Cs ?-rays. Their electron spin resonance (ESR) spectra pre- and post-irradiated were measured and the changes of ESR signal intensities were analyzed. The results showed that the average intensity of native signals of dog tooth samples was 20.8±2.9, much weaker than that of human 39.5; the dosimetric signal intensities of dog tooth enamel increased with the absorbed doses; the mass of each sample is 100 mg. The average irradiation response of dog tooth enamel samples was (37.1±2.1) Gy-1, very close to that of human tooth samples (36.3 Gy-1). The dog tooth can be used for retrospective dosimetry when human tooth are difficult to collect. (authors)

122

Biomechanical effects of splint types on traumatized tooth: a photoelastic stress analysis.  

Science.gov (United States)

This study was undertaken to assess the effect of splint type on stresses occurring around traumatized tooth by photoelastic stress analysis. Three semi-rigid splint types--a wire-composite splint, fiberglass splint and titanium trauma splint--were utilized for comparisons. Extracted left upper central and lateral incisors and the canine tooth of an otherwise healthy patient were embedded equidistantly in photoelastic resin. For all cases studied, a static axial and 20 degrees oblique force of 100 N was applied on the lateral incisor in separate sessions. The experiments were undertaken without any splint application (unsplinted, control) after which the splints, adhesively bonded to the labial aspects of teeth, were consecutively tested. During each loading sequence, generation of isochromatic fringes was observed in the field of a polariscope, and photographed by a digital camera. Quantification of fringes was performed on magnified images, transferred to a PC. Under vertical loading, the highest stresses in the apical regions were observed for the unsplinted and ribbond-splint groups, whereas the lowest fringes occurred with the use of orthodontic wire as a splinting medium. Titanium trauma splint had absolutely no effect on reduction of stresses, as the fringe orders were slightly higher than the unsplinted lateral tooth. The use of orthodontic wire resulted in lowest fringe orders around the traumatized tooth. PMID:16643288

Burcak Cengiz, Sevi; Stephan Atac, Atilla; Cehreli, Zafer C

2006-06-01

123

Tooth in Ethmoid Sinus: A Case Report  

Directory of Open Access Journals (Sweden)

Full Text Available Ectopic eruption of teeth occurs in a variety of locations.Commonly seen in palate and maxillary sinus, they have alsobeen reported in nasal cavity, orbit, mandibular condyle,coronoid process, and facial skin.Here, we report a rare case of recurrent sinusitis caused byectopic tooth in right ethmoid sinus and successful endoscopicremoval of it. The symptoms of the patient disappeared aftersurgery. Such case has not been yet reported in the Englishliterature.Ectopic tooth is an uncommon cause of sinusitis. It shouldbe considered in patients presenting with recurrent sinusitis unresponsiveto medical treatment. Computed tomography of thesinuses is the modality of choice for diagnosis. Endoscopic sinussurgery is the best method for management of such cases.

Tayebe Kazemei

2009-09-01

124

Saw-tooth shaped lower hybrid waves  

International Nuclear Information System (INIS)

A homogeneous magnetised plasma supports three types of low frequency electrostatic oscillations. Of these, lower hybrid waves across the external magnetic fields can produce enhanced particle diffusion. Non-linear propagation of a finite amplitude lower hybrid wave is investigated. It is shown that the nonlinearity associated with the ion inertial motion gives rise to wave steepening and since wave dispersion cannot compete with nonlinearity the waves evolve into a saw-tooth shaped profile (UK)

125

The evolution of tooth wear indices  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tooth wear—attrition, erosion and abrasion—is perceived internationally as an ever-increasing problem. Clinical and epidemiological studies, however, are difficult to interpret and compare due to differences in terminology and the large number of indices that have been developed for diagnosing, grading and monitoring dental hard tissue loss. These indices have been designed to identify increasing severity and are usually numerical. Some record lesions on an aetiological basis (e.g. erosio...

Bardsley, Penny Fleur

2008-01-01

126

Retrospective biodosimetry with small tooth enamel samples using K-Band and X-Band  

Energy Technology Data Exchange (ETDEWEB)

In an attempt to make the in vitro electron spin resonance (ESR) retrospective dosimetry of the tooth enamel a lesser invasive method, experiments using X-Band and K-Band were performed, aiming to determine conditions that could be used in cases of accidental exposures. First, a small prism from the enamel was removed and ground with an agate mortar and pestle until particles reach a diameter of approximately less than 0.5 mm. This enamel extraction process resulted in lower signal artifact compared with the direct enamel extraction performed with a diamond burr abrasion. The manual grinding of the enamel does not lead to any induced ESR signal artifact, whereas the use of a diamond burr at low speed produces a signal artifact equivalent to the dosimetric signal induced by a dose of 500 mGy of gamma irradiation. A mass of 25 mg of enamel was removed from a sound molar tooth previously irradiated in vitro with a dose of 100 mGy. This amount of enamel was enough to detect the dosimetric signal in a standard X-Band spectrometer. However using a K-Band spectrometer, samples mass between 5 and 10 mg were sufficient to obtain the same sensitivity. An overall evaluation of the uncertainties involved in the process in this and other dosimetric assessments performed at our laboratory indicates that it is possible at K-Band to estimate a 100 mGy dose with 25% accuracy. In addition, the use of K-Band also presented higher sensitivity and allowed the use of smaller sample mass in comparison with X-Band. Finally, the restoration process performed on a tooth after extraction of the 25 mg of enamel is described. This was conducted by dental treatment using photopolymerizable resin which enabled complete recovery of the tooth from the functional and aesthetic viewpoint showing that this procedure can be minimally invasive.

Gomez, Jorge A. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Kinoshita, Angela [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Universidade Sagrado Coracao - USC, 17011-160 Bauru, Sao Paulo (Brazil); Leonor, Sergio J. [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Belmonte, Gustavo C. [Universidade Sagrado Coracao - USC, 17011-160 Bauru, Sao Paulo (Brazil); Baffa, Oswaldo, E-mail: baffa@usp.br [Departamento de Fisica, FFCLRP, Universidade de Sao Paulo, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

2011-09-15

127

Retrospective biodosimetry with small tooth enamel samples using K-Band and X-Band  

International Nuclear Information System (INIS)

In an attempt to make the in vitro electron spin resonance (ESR) retrospective dosimetry of the tooth enamel a lesser invasive method, experiments using X-Band and K-Band were performed, aiming to determine conditions that could be used in cases of accidental exposures. First, a small prism from the enamel was removed and ground with an agate mortar and pestle until particles reach a diameter of approximately less than 0.5 mm. This enamel extraction process resulted in lower signal artifact compared with the direct enamel extraction performed with a diamond burr abrasion. The manual grinding of the enamel does not lead to any induced ESR signal artifact, whereas the use of a diamond burr at low speed produces a signal artifact equivalent to the dosimetric signal induced by a dose of 500 mGy of gamma irradiation. A mass of 25 mg of enamel was removed from a sound molar tooth previously irradiated in vitro with a dose of 100 mGy. This amount of enamel was enough to detect the dosimetric signal in a standard X-Band spectrometer. However using a K-Band spectrometer, samples mass between 5 and 10 mg were sufficient to obtain the same sensitivity. An overall evaluation of the uncertainties involved in the process in this and other dosimetric assessments performed at our laboratory indicates that it is possible at K-Band to estimate a 100 mGy dose with 25% accuracy. In addition, the use of K-Band also presented higher sensitivity and allowed the use of smaller sample mass in allowed the use of smaller sample mass in comparison with X-Band. Finally, the restoration process performed on a tooth after extraction of the 25 mg of enamel is described. This was conducted by dental treatment using photopolymerizable resin which enabled complete recovery of the tooth from the functional and aesthetic viewpoint showing that this procedure can be minimally invasive.

128

Radiosterilization of tooth pastes EF, MB, LK  

International Nuclear Information System (INIS)

The effect of decontaminating doses of gamma rays (60Co, 10 Kr - 1.5 Mr) on the quality and biological activity of tooth pastes is studied. The radioresistance factors D10 of the dominating microorganisms in the studied pastes, namely Bac. subtilis, Staph. epidermidis, S. lutea, Ps. aeruginosa, Pen. notatum, Pen. chrysogenum, Asp. niger, C. parapsilosis, are determined. Ps aeruginosa appears to show the highest radiosensitivity - D10 = 20 Kr. The irradiation in the range 500 Kr - 1.5 Mr reveals that Ps. aeruginosa are inactivated with doses of 750 Kr while the inactivation of sporebearing bacteria and grampositive microorganisms starts at doses above 1 Mr. The lower values of radioresistance factors observed as compared to that established by the authors for cosmetic preparations henna and starch are due to radiosensitizing of microorganisms in a medium with higher water content. The radiolytic effect of water causes changes in consistency, odour, taste and colour of the tooth pastes and for that reason the radiosterilization of tooth pastes is not recommended. A mathematical model for irradiation of products contaminated with a variety of microorganisms is developed. Bac. subtilis - the most frequent and radioresistant pollutant - is suggested as a standard in selecting the proper sterilization procedure and in checking the efficiency of irradiation. 3 tabs, 3 figs, 6 refs

129

Digital Computer Matching of Tooth Color  

Directory of Open Access Journals (Sweden)

Full Text Available This study aimed to determine the validity of the digital photocolorimetric (PCM method in matching the color of human teeth. First, two Vitapan Classical shade guides, each containing 16 shade guide teeth, were visually shade matched, and digital photographs of each three pair of shade guide teeth were taken in a color matching booth. Secondly, visual shade matching of the upper central incisors of 48 subjects was performed by two prosthodontists independently in a chair, using the Vitapan Classical shade guide. The three closest shade guide teeth were visually selected and ranked in order of preference, for which digital photographs were taken under ceiling daylight-corrected fluorescent lighting. All digital images were analyzed on a computer screen using software to calculate the color difference between the reference tooth and other teeth in the same digital image. The percent color matching for the shade guide teeth and human teeth was 88% and 75%, respectively. There was no statistically significant difference in matching the tooth color between the shade guide teeth and human teeth. The digital PCM method is valid for the range of human teeth based on the Vitapan Classical shade guide. This method enhances communication with the laboratory personnel in matching the tooth color.

Won-suk Oh

2010-06-01

130

A report of an impacted primary maxillary central incisor tooth.  

Science.gov (United States)

Primary tooth impaction is a rare phenomenon when compared to permanent teeth impaction. The purpose of this report is to present a 5-year-old Chinese girl who exhibited impaction of tooth 51, its unusual consequence on the permanent successor tooth and its comprehensive management. Her parents revealed that at 6 months of age, the patient had fallen from her bed and struck her face on the floor; however, there were no teeth present in the oral cavity. The intraoral examinations identified a bony-like projection on the buccal aspect of the alveolus in the 51 region. Radiographic examination revealed that tooth 51 exhibited an unfavourable orientation, with the crown directed towards the palate. Therefore, the impacted tooth 51 was surgically removed, and two years later tooth 11 erupted into the oral cavity with an indentation on its incisal aspect, which resembled the crown of the primary teeth, thus giving the appearance of a tooth within a tooth or 'dens in dente'. Subsequently, enameloplasty and composite resin build-up was performed on tooth 11 for aesthetic reasons. It is very unusual to have the clinical crowns of both primary and permanent teeth in such close proximity within the alveolar bone, and the present case is a good example to emphasize that trauma to the primary teeth is of considerable importance due to the close proximity of the primary teeth to permanent tooth germs. PMID:23305157

Anthonappa, Robert P; Ongtengco, Kristine L; King, Nigel M

2013-10-01

131

Evaluation of specific activity of acid phosphatase in gingival crevicular fluid during orthodontic tooth movements  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Analysis of gingival crevicular fluid (GCF may be a good means of examining the biochemical processes associated with bone turnover. The aim of this study was to evaluate the specific activity of acid phosphatase (ACP in GCF during canine retraction with sliding technique.Materials and Methods: In this clinical trial 5 subjects (aged 12–20 years with bimaxillary dentoalveolar protrusion were selected. After extraction of four first premolars, the sliding technique was used to retract canines in each subject. GCF samples were collected from the distal aspect of each canine by using sterile paper points (#15 at four time intervals: immediately after the appliances were fitted, at the time of initial activation, and 15 and 30 days afterwards. Acid phosphatase and microprotein levels were assayed by means of quantitative colorimetric technique. Tooth movement at each sampling interval was measured. Data was analyzed with non-parametric tests of Freeman, Mann-Whitney, and Pearson’s correlation coefficient (?=0.05. Results: After activation of the appliances, average specific activity of acid phosphatase in GCF significantly increased (p value < 0.001. In addition, the specific activity of ACP at sampling intervals showed significant differences (p value < 0.001. No significant relation was noted between changes in specific activity of ACP and tooth movement (p value = 0.215.Conclusion: It is possible to measure specific activity of acid phosphatase in the GCF during orthodontic tooth movements. It is elevated in the pressure side during orthodontic tooth movement. Key words: Acid phosphatase, Gingival crevicular fluid, Tooth movement.

Arash Motaghi

2011-01-01

132

Evaluating tooth restorations: micro-computed tomography in practical training for students in dentistry  

Science.gov (United States)

Direct composite fillings belong to widespread tooth restoration techniques in dental medicine. The procedure consists of successive steps, which include etching of the prepared tooth surface, bonding and placement of composite in incrementally built up layers. Durability and lifespan of the composite inlays strongly depend on the accurate completion of the individual steps to be also realized by students in dental medicine. Improper handling or nonconformity in the bonding procedure often lead to air enclosures (bubbles) as well as to significant gaps between the composite layers or at the margins of the restoration. Traditionally one analyzes the quality of the restoration cutting the tooth in an arbitrarily selected plane and inspecting this plane by conventional optical microscopy. Although the precision of this established method is satisfactory, it is restricted to the selected two-dimensional plane. Rather simple micro computed tomography (?CT) systems, such as SkyScan 1174™, allows for the non-destructive three-dimensional imaging of restored teeth ex vivo and virtually cutting the tomographic data in any desired direction, offering a powerful tool for inspection of the restored tooth with micrometer resolution before cutting and thus also to select a two-dimensional plane with potential defects. In order to study the influence of the individual steps on the resulted tooth restoration, direct composite fillings were placed in mod cavities of extracted teeth. After etching, an adhesive was applied in half of the specimens. From the tomographic datasets, it becomes clear that gaps occur more frequently when bonding is omitted. The visualization of air enclosures offers to determine the probability to find a micrometer-sized defect using an arbitrarily selected cutting plane for inspection.

Deyhle, Hans; Schmidli, Fredy; Krastl, Gabriel; Müller, Bert

2010-09-01

133

Tooth form design supporting system in module design  

Science.gov (United States)

A lot of time was spent in designing the tooth form because there was no Computer Aided Design (CAD) system suitable for designing the tooth form of gears. A CAD system to support the tooth form design to promote efficiency of the tooth form design of gears for a wristwatch was developed. This system can perform calculation of torque transmission factor of gears, automatic drawing of tooth form drawing, and engagement simulation, and by utilizing this system the tooth form can be designed in less than one fourth of the time required by the conventional method. The characteristics of the system used to calculate the torque transmission factor of a pair of gears are summarized and the displayed results are shown.

Nagasawa, Junji; Namiki, Ryou; Tanaka, Souichi; Aoyama, Shigeru

134

The interactions between attrition, abrasion and erosion in tooth wear.  

Science.gov (United States)

Tooth wear is the result of three processes: abrasion (wear produced by interaction between teeth and other materials), attrition (wear through tooth-tooth contact) and erosion (dissolution of hard tissue by acidic substances). A further process (abfraction) might potentiate wear by abrasion and/or erosion. Knowledge of these tooth wear processes and their interactions is reviewed. Both clinical and experimental observations show that individual wear mechanisms rarely act alone but interact with each other. The most important interaction is the potentiation of abrasion by erosive damage to the dental hard tissues. This interaction seems to be the major factor in occlusal and cervical wear. The available evidence is insufficient to establish whether abfraction is an important contributor to tooth wear in vivo. Saliva can modulate erosive/abrasive tooth wear, especially through formation of pellicle, but cannot prevent it. PMID:24993256

Shellis, R Peter; Addy, Martin

2014-01-01

135

Results of tooth enamel EPR dosimetry for population living in the vicinity of the Semipalatinsk nuclear test site  

Energy Technology Data Exchange (ETDEWEB)

The method of electron paramagnetic resonance (EPR) dosimetry was used on human tooth enamel to obtain individual absorbed doses of residents of settlements in the vicinity of the Nuclear Test Site (SNTS) in Semipalatinsk region, Kazakhstan. Measured teeth were extracted according to medical indications. In total, 105 tooth enamel samples were analyzed, including eight tooth samples from control settlement Kokpekty, which is located 400 km to the Southeast from SNTS and was not subjected to any radioactive contamination. It was found that the excess doses obtained after subtraction of the contribution of natural background radiation ranged up to about 440 mGy for residents of Dolon, whose tooth enamel was formed before 1949, and do not exceed 100 mGy for younger residents. For residents of Mostik, excess doses do not exceed 100 mGy for all ages except in one resident, for whom an extremely high dose of 1250 mGy was registered. For Bodene settlement, excess doses higher than 100 mGy were obtained for two samples from the residents having enamel formed before 1949. An extremely high dose (2800{+-}400 mGy) was obtained for one resident of Semipalatinsk City. The average excess dose for Semipalatinsk samples with enamel formation before 1949 was determined close to the average excess dose for tooth enamel samples from Dolon village.

Zhumadilov, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan)], E-mail: kassym@hiroshima-u.ac.jp; Ivannikov, A. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Medical Radiological Research Center, Obninsk, 249036 (Russian Federation); Apsalikov, K. [Scientific-Research Institute for Radiation Medicine and Ecology, Semipalatinsk 490050 (Kazakhstan); Zhumadilov, Zh. [Semipalatinsk State Medical Academy, Semipalatinsk 490050 (Kazakhstan); Zharlyganova, D. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Stepanenko, V.; Skvortsov, V. [Medical Radiological Research Center, Obninsk, 249036 (Russian Federation); Berekenova, G. [Scientific-Research Institute for Radiation Medicine and Ecology, Semipalatinsk 490050 (Kazakhstan); Toyoda, S. [Department of Applied Physics Faculty of Science Okayama University of Science, 700-0005 (Japan); Endo, S.; Tanaka, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Miyazawa, C. [School of Dentistry, Ohu University, Koriyama-shi, Fukushima Pref. 963-8611 (Japan); Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan)

2007-07-15

136

Instrumental selection of tooth color in prosthodontic rehabilitation  

Directory of Open Access Journals (Sweden)

Full Text Available Tooth color selection in prosthodontics is a very important factor for successful rehabilitation. The aim of this paper was to present different instruments for tooth color selection in prosthodontic rehabilitation. Knowledge of basic principles of a complex psychophysical phenomenon such as color is of essential interest in prosthodontic therapy. Furthemore, the mechanism of physiological perception of color and available methods for an objective determination of tooth color are also presented in the paper.

?uriši? Slobodan

2007-01-01

137

Primary impaction of a primary in incisor tooth: a case report  

Directory of Open Access Journals (Sweden)

Full Text Available The primary impaction is the situation in which a tooth is retained inthe mouth and remains unerupted for a period upper six months whencompared to teeth of the other side. It is a very rare condition in primary teeth especially in maxillary anterior teeth. The purpose of this article is to present a case of a 2-year and 11-month old female child with an impacted primary upper central incisor. The main complaint was the absence of the anterior tooth in the mouth. There was a previous history of trauma when the child was four months old. Clinical and radiographic examinations are described. The treatment consisted of a period of clinical and radiographic control, with the extraction of the impacted primary upper central incisor and a follow-up until the eruption of the permanent successor. This case emphasizes the possible relationship between previous trauma and primary impaction.

Maria Naira Pereira FRIGGI

2007-05-01

138

The effects of periradicular inflamation and infection on a primary tooth and permanent successor.  

Science.gov (United States)

Primary teeth and the permanent successors must be understood as interdependent units, where each one of them interacts with and depends on each other. Pulpal inflammation/infection of a primary tooth and the spread of this condition over the periradicular tissues can lead to alterations in the dental germ of the permanent successor and to the surrounding structures if no therapy is done, i.e. endodontics or extraction. This work will present cases of permanent teeth that showed alteration in eruption and / or in development, as a consequence of inflammation / infection of the preceding primary teeth, such as: hypoplasia, morphological alteration on the dental crown or total arrest of. radicular formation. The teeth analysed in this study belong to patients who attended the Universidade Federal de Santa Catarina Children's Dentistry Clinic. The earlier these lesions are diagnosed, the less were the destructive effects and the consequences on the primary tooth/permanent germ unit. PMID:15926433

Cordeiro, Mabel Mariela Rodriguez; Rocha, Maria Jose de Carvalho

2005-01-01

139

ESR dosimetry for atomic bomb survivors using shell buttons and tooth enamel  

International Nuclear Information System (INIS)

Atomic bomb radiation doses to humans at Nagasaki and Hiroshima are investigated by electron spin resonance (ESR) from shell buttons and tooth enamel voluntarily supplied by survivors. A shell button gives a dose of 2.1+-0.2 Gy with ESR signals at g=2.001 and g=1.997 while the signal at g=1.997 for the tooth enamel of the same person is 1.9+-0.5 Gy. Other teeth show doses from about 0.5 Gy to 3 Gy. An apparent shielding converted to a concrete thickness is given using the T65D calculated in 1965. Teeth extracted during dental treatment should be preserved for cumulative radiation dosimetry. (author)

140

Tooth-marked small theropod bone: an extremely rare trace  

DEFF Research Database (Denmark)

Tooth-marked dinosaur bones provide insight into feeding behaviours and biting strategies of theropod dinosaurs. The majority of theropod tooth marks reported to date have been found on herbivorous dinosaur bones, although some tyrannosaurid bones with tooth marks have also been reported. In 1988 a partial skeleton of the dromaeosaurid Saurornitholestes was collected from southern Alberta, Canada, that bore marks on one dentary. The location and morphology of the tooth marks suggests that a theropod (possible a juvenile tyrannosaurid) included a Saurornitholestes in its diet.

Jacobsen, Aase Roland

2001-01-01

 
 
 
 
141

Tooth-shaped plasmonic waveguide filters with nanometeric sizes  

CERN Document Server

A novel nanometeric plasmonic filter in a tooth-shaped Metal-Insulator-Metal waveguide is proposed and demonstrated numerically. An analytic model based on the scattering matrix method is given. The result reveals that the single tooth-shaped filter has a wavelength filtering characteristic and an ultra-compact size in the length of a few hundred nanometers, compared to grating-like SPPs filters. Both analytic and simulation results show that the wavelength of the trough of the transmission has linear and nonlinear relationships with the tooth depth and the tooth width, respectively. The waveguide filter could be utilized to develop ultra-compact photonic filters for high integration.

Lin, Xianshi; 10.1364/OL.33.002874

2009-01-01

142

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Science.gov (United States)

... 2010-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

2010-04-01

143

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Science.gov (United States)

...2010-04-01 false Bracket adhesive resin and tooth conditioner...HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES ...Devices § 872.3750 Bracket adhesive resin and tooth conditioner...Identification. A bracket adhesive resin and tooth...

2010-04-01

144

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Science.gov (United States)

...2010-04-01 false Bracket adhesive resin and tooth conditioner...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner...Identification. A bracket adhesive resin and tooth...

2010-04-01

145

Fate of HERS during tooth root development.  

Science.gov (United States)

Tooth root development begins after the completion of crown formation in mammals. Previous studies have shown that Hertwig's epithelial root sheath (HERS) plays an important role in root development, but the fate of HERS has remained unknown. In order to investigate the morphological fate and analyze the dynamic movement of HERS cells in vivo, we generated K14-Cre;R26R mice. HERS cells are detectable on the surface of the root throughout root formation and do not disappear. Most of the HERS cells are attached to the surface of the cementum, and others separate to become the epithelial rest of Malassez. HERS cells secrete extracellular matrix components onto the surface of the dentin before dental follicle cells penetrate the HERS network to contact dentin. HERS cells also participate in the cementum development and may differentiate into cementocytes. During root development, the HERS is not interrupted, and instead the HERS cells continue to communicate with each other through the network structure. Furthermore, HERS cells interact with cranial neural crest derived mesenchyme to guide root development. Taken together, the network of HERS cells is crucial for tooth root development. PMID:19576204

Huang, Xiaofeng; Bringas, Pablo; Slavkin, Harold C; Chai, Yang

2009-10-01

146

Thermal analysis of gamma irradiated tooth enamel  

International Nuclear Information System (INIS)

Tooth enamel samples are prepared. and irradiated at room temperature with 60Co gamma rays at different dose levels ranging from 5 to 5000 Gy. Thermal analysis (DTA) and (TGA) for the non-irradiated and irradiated tooth enamel samples were measured. The results indicate that for non-irradiated sample there is two phase transitions in the DTA spectrum. Very probably the first peak is an exothermic transition in the range 250-400 degree c at a peak maximum 333.7 degree c which attributed to heat of crystallization of the amorphous part of calcium phosphate present in hydroxyapatite. The second phase transition is at about 911.62 degree c, which is corresponding to the decomposition of. CaCO3, and transformation of a part of hydroxyapatite (HA) to oxy hydroxyapatite (OHA). Meanwhile, for the irradiated samples the crystallization temperature decreases as a result of the heat energy of gamma radiation. The results are confirmed by the thermogravimetric analysis, which consists of three steps: the first step is attributed to the loss of the adsorbed water, the second step is corresponding to the lattice water and combustion of organic material, and the third step is corresponding to evolution of CO2 as a result. of dissociation of CaCO3

147

Hierarchical structure and biomineralization in cricket tooth  

CERN Document Server

Cricket is a truculent insect with stiff and sharp teeth as a fighting weapon. The structure and possible biomineralization of the cricket teeth are always interested. Synchrotron radiation X-ray fluorescence, X-ray diffraction and small angle X-ray scattering techniques were used to probe the element distribution, possible crystalline structures and size distribution of scatterers in cricket teeth. Scanning electron microscope was used to observe the nanoscaled structure. The results demonstrate that Zn is the main heavy element in cricket teeth. The surface of the cricket teeth has a crystalline compound like ZnFe2(AsO4)2(OH)2(H2O)4. While, the interior of the teeth has a crystalline compound like ZnCl2, which is from the biomineralization. The ZnCl2-like biomineral forms nanoscaled microfibrils and their axial direction points at the top of tooth cusp. The microfibrils aggregate random into intermediate filaments, forming a hierarchical structure. A sketch map of the cricket tooth cusp was proposed and a d...

Xing, Xueqing; Cai, Quan; Mo, Guang; Du, Rong; Chen, Zhongjun; Wu, Zhonghua

2012-01-01

148

Specificity protein 7 is not essential for tooth morphogenesis.  

Science.gov (United States)

Tooth formation is a multifaceted process involving numerous interactions between oral epithelium and neural crest derived ecto-mesenchyme from morphogenesis to cyto-differentiation. The precise molecular regulator that drives the cyto-differentiation and dynamic cross-talk between the two cell types has yet to be fully understood. Runx2 along with its downstream target Sp7 are essential transcription factors for development of the mineralizing cell types. Global knockout of the Runx2 gene results in an arrest of tooth morphogenesis at the late bud stage. Like Runx2, Sp7-null mutants exhibit peri-natal lethality and are completely devoid of alveolar bone. However, the role of Sp7 in tooth development remains elusive. Here, we report the effects of Sp7 deletion on tooth formation. Surprisingly, tooth morphogenesis progresses normally until the mid bell stage in Sp7-homozygous mutants. Incisors and multi-cusped first and second molars were noted in both littermates. Thus, formation of alveolar bone is not a prerequisite for tooth morphogenesis. Tooth organs of Sp7-null however, were significantly smaller in size when compared to WT. Differentiation of both ameloblasts and odontoblasts was disrupted in Sp7-null mice. Only premature and disorganized ameloblasts and odontoblasts were noted in mutant mice. These data indicate that Sp7 is not required for tooth morphogenesis but is obligatory for the functional maturation of both ameloblasts and odontoblasts. PMID:25158188

Clarke, John C; Bae, Ji-Myung; Adhami, Mitra; Rashid, Harunur; Chen, Haiyan; Napierala, Dobrawa; Gutierrez, Soraya E; Sinha, Krishna; Crombrugghe, Benoit de; Javed, Amjad

2014-08-01

149

Interleukin-1beta levels, pain intensity, and tooth movement using two different magnitudes of continuous orthodontic force.  

Science.gov (United States)

This study aimed to determine the optimum orthodontic force from a broader perspective. Interleukin (IL)-1? levels in human gingival crevicular fluid (GCF), pain intensity, and the amount of tooth movement were measured during canine retraction using different magnitudes of continuous orthodontic force. Sixteen subjects (two males and 14 females), aged 18-24 years, diagnosed with Class I bimaxillary protrusion and treated with first premolar extractions participated in this study. The upper canines were retracted with continuous forces of 50 or 150 g using nickel-titanium coil springs on segmented archwires. One of the lower canines was used as a control. GCF was collected from the distal site of each tooth at specific time points. IL-1? concentrations, pain intensity, using the visual analogue scale (VAS), and the amount of tooth movement were evaluated. One-way analysis of variance, Friedman, and paired t-tests were used for comparisons of IL-1? in GCF, the plaque and gingival indices, and the efficiency of tooth movement on pain perception, respectively. IL-1? concentration in the 150 g group showed the highest level at 24 hours and 2 months with significant differences compared with the control group (P < 0.05). The mean VAS score of pain intensity from the 150 g force was significantly greater than from the 50 g force at 24 hours (P < 0.01). However, no significant difference in the amount of tooth movement was found between these two different magnitudes of continuous force at 2 months. A 50 g force could effectively induce tooth movement similar to 150 g with less pain and less inflammation. PMID:20534713

Luppanapornlarp, Suwannee; Kajii, Takashi S; Surarit, Rudee; Iida, Junichiro

2010-10-01

150

Maxillary single-tooth replacement utilizing a novel ceramic restorative system: results to 30 months.  

Science.gov (United States)

This study reports on the first longitudinal results of an alumina (70%)-zirconia (30%) ceramic restorative system for implant-supported, single-tooth replacement in the anterior maxillary jaw. Eighteen patients (9 men, 9 women, mean age = 42.4 years) were treated with 22 implants placed into 19 extraction sockets and 3 residual ridges. Eight implants were immediately loaded with nonoccluding provisional prostheses. All implants were definitively loaded with fully occluding ceramic restorations after osseointegration and soft tissue maturation. Patients were monitored from 7 to 30 months (mean = 18.1 months) after loading. All implants osseointegrated and were successfully restored. One case of abutment screw loosening occurred because of patient parafunction (bruxing), and another patient reported chewing pain attributed to malocclusion. Both problems were successfully resolved without further incidence. Within the context of this study, single-tooth replacement in the anterior maxillary jaw was successfully achieved with alumina-zirconia ceramic single-tooth restorations with up to 30 months of clinical function. PMID:17009564

Ormianer, Zeev; Schiroli, Guido

2006-01-01

151

Enfermedad de Charcot Marie Tooth en un niño Charcot-Marie-Tooth disease in a child  

Directory of Open Access Journals (Sweden)

Full Text Available Se presenta el caso clínico de un niño de 7 años de edad con enfermedad de Charcot Marie Tooth, atendido en el Servicio de Rehabilitación del Hospital Infantil Norte Docente "Dr. Juan de la Cruz Martínez Maceira" de Santiago de Cuba para recibir tratamiento rehabilitador. Luego del programa terapéutico aplicado el paciente mejoró el trofismo y la fuerza muscular, disminuyeron las deformidades del pie y ocurrieron importantes cambios en la marcha, de modo que la rehabilitación oportuna evitó el tratamiento quirúrgico.The case of a 7 year-old boy with Charcot- Marie-Tooth disease, who was attended at the Rehabilitation Department of "Dr. Juan de la Cruz Martínez Maceira" Northern Teaching Children Hospital in Santiago de Cuba for rehabilitation treatment is reported. After receiving a therapeutic program the patient improved his muscle strenght and trophism, foot deformities decreased and significant changes occurred in gait, so that timely rehabilitation prevented surgical treatment.

Teresa Vidal Pérez

2012-11-01

152

Clinical and histologic healing of human extraction sockets filled with calcium sulfate.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

PURPOSE: The aim of this investigation was to evaluate whether the placement of medical-grade calcium sulfate hemihydrate (MGCSH) in fresh extraction sockets might affect the quality of newly formed bone and influence crestal bone changes. MATERIALS AND METHODS: Forty patients who needed maxillary single-tooth extraction followed by implant insertion were enrolled in the study. Alveoli were required to have four remaining intact walls. After tooth extraction, 22 patients received MGCSH in the...

Aimetti, Mario; Romano, Federica

2009-01-01

153

Allogenic tooth transplantation inhibits the maintenance of dental pulp stem/progenitor cells in mice.  

Science.gov (United States)

Our recent study suggested that allogenic tooth transplantation may affect the maintenance of dental pulp stem/progenitor cells. This study aims to elucidate the influence of allograft on the maintenance of dental pulp stem/progenitor cells following tooth replantation and allo- or auto-genic tooth transplantation in mice using BrdU chasing, immunohistochemistry for BrdU, nestin and Ki67, in situ hybridization for Dspp, transmission electron microscopy and TUNEL assay. Following extraction of the maxillary first molar in BrdU-labeled animals, the tooth was immediately repositioned in the original socket, or the roots were resected and immediately allo- or auto-grafted into the sublingual region in non-labeled or the same animals. In the control group, two types of BrdU label-retaining cells (LRCs) were distributed throughout the dental pulp: those with dense or those with granular reaction for BrdU. In the replants and autogenic transplants, dense LRCs remained in the center of dental pulp associating with the perivascular environment throughout the experimental period and possessed a proliferative capacity and maintained the differentiation capacity into the odontoblast-like cells or fibroblasts. In contrast, LRCs disappeared in the center of the pulp tissue by postoperative week 4 in the allografts. The disappearance of LRCs was attributed to the extensive apoptosis occurring significantly in LRCs except for the newly-differentiated odontoblast-like cells even in cases without immunological rejection. The results suggest that the host and recipient interaction in the allografts disturbs the maintenance of dense LRCs, presumably stem/progenitor cells, resulting in the disappearance of these cell types. PMID:24671256

Saito, Kotaro; Nakatomi, Mitsushiro; Kenmotsu, Shinichi; Ohshima, Hayato

2014-05-01

154

Unusual intraosseous transmigration of impacted tooth  

International Nuclear Information System (INIS)

Transmigration of an impacted tooth through the symphyseal suture is a rare and special developmental anomaly of unknown etiology that is unique to the mandibular canine. Maxillary canine transmigration is even rarer. Transmigrated canines are particularly significant due to the aesthetic and functional importance. A maxillary lateral incisor crossing the mid-palatal suture has never been reported in the literature. The aim of this report is to present the first case of simultaneous transmigration of a lateral incisor and canine in the maxilla. The paper also reports four unusual cases of unilateral canine transmigration in the maxilla and mandible and successful eruption of one of the transmigrated mandibular canines following orthodontic traction. Etiology of transmigration and its clinical considerations are also discussed.

155

Update on Charcot-Marie-Tooth disease.  

Science.gov (United States)

Charcot-Marie-Tooth disease (CMT) disease encompasses a genetically heterogeneous group of inherited neuropathies, also known as hereditary motor and sensory neuropathies. CMT results from mutations in more than 40 genes expressed in Schwann cells and neurons causing overlapping phenotypes. The classic CMT phenotype reflects length-dependent axonal degeneration characterized by distal sensory loss and weakness, deep tendon reflex abnormalities, and skeletal deformities. Recent articles have provided insight into the molecular pathogenesis of CMT, which, for the first time, suggest potential therapeutic targets. Although there are currently no effective medications for CMT, multiple clinical trials are ongoing or being planned. This review will focus on the underlying pathomechanisms and diagnostic approaches of CMT and discuss the emerging therapeutic strategies. PMID:21080241

Patzkó, Agnes; Shy, Michael E

2011-02-01

156

Challenges in assessing erosive tooth wear.  

Science.gov (United States)

Indices for assessing erosive wear are expected to deliver more than is expected of an ideal index: simple with defined scoring criteria so that it is reproducible, reflective of the aetiology of the condition and accurately categorizing shape, area and depth of affect, both at a point in time (prevalence) and longitudinally (incidence/increment). In addition, the differential diagnosis of erosive wear is complex, as it usually co-exists with other types of tooth wear. Therefore, a valid recording of erosive wear at an individual as well as at a population level without a thorough history with respect to general health, diet and habits is a challenge. The aims of this chapter are to describe the potential methodological challenges in assessing erosive wear, to critique the strengths and limitations of the existing erosion indices and to propose the adoption of a validated erosion index for the purpose for which it is intended. PMID:24993257

Margaritis, Vasileios; Nunn, June

2014-01-01

157

Is erosive tooth wear an oral disease?  

Science.gov (United States)

Erosive tissue loss is part of the physiological wear of teeth. Clinical features are an initial loss of tooth shine or luster followed by flattening of convex structures; with continuing acid exposure, concavities form on smooth surfaces, or grooving and cupping occur on incisal/occlusal surfaces. Dental erosion must be distinguished from other forms of wear, but can also contribute to general tissue loss by surface softening, thus modifying physical wear processes. The determination of dental erosion as a condition or pathology is relatively easy in the case of pain or endodontic complications, but is ambiguous in initial stages and in terms of function or esthetics. The impact of dental erosion on oral health is discussed. However, it can be concluded that in most cases dental erosion is best described as a condition, with the acid being of nonpathological origin. PMID:24993254

Ganss, Carolina

2014-01-01

158

Abrasive Wear of Digger Tooth Steel  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of silicon carbide SiC abrasive particles of 20, 30, 40, 50 and60?m size on carburized digger tooth steel was studied. Four types of steel, withdifferent hardness, were tested at two constant linear sliding speeds and undervarious loads of 10, 20, 30, 40 and 50N. Tests were carried out for sliding time of0.5, 1.0, 1.5, 2.0 and 2.5min. Experimental results showed that there wasconsistent reduction in abrasive wear as the hardness of the materials wasincreased. It was found that wear increased with the increase of applied load,linear sliding speed and sliding time. Also, it was noticed that the wear increasedwith increase in abrasive particle size, and the most effective size was 40 ?m.SEM observations of the worm surface showed that the cutting and ploughingwere the dominant abrasive wear mechanisms.

Hussein Sarhan sarhan, Nofal Al-Araji, Rateb Issa , Mohammad Alia

2011-08-01

159

EPR tooth dosimetry of SNTS area inhabitants  

Energy Technology Data Exchange (ETDEWEB)

The determination of external dose to teeth of inhabitants of settlements near the Semipalatinsk Nuclear Test Site (SNTS) was conducted using the EPR dosimetry technique to assess radiation doses associated with exposure to radioactive fallout from the test site. In this study, tooth doses have been reconstructed for 103 persons with all studied teeth having been formed before the first nuclear test in 1949. Doses above those received from natural background radiation, termed 'accident doses', were found to lie in the range from zero to approximately 2 Gy, with one exception, a dose for one person from Semipalatinsk city was approximately 9 Gy. The variability of reconstructed doses within each of the settlements demonstrated heterogeneity of the deposited fallout as well as variations in lifestyle. The village mean external gamma doses for residents of nine settlements were in the range from a few tens of mGy to approximately 100 mGy.

Sholom, Sergey [Scientific Center for Radiation Medicine, Melnikova str., 53, Kiev (Ukraine); Desrosiers, Marc [Ionizing Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD (United States); Bouville, Andre; Luckyanov, Nicholas [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 6120 Executive Boulevard, Bethesda, MD (United States); Chumak, Vadim [Scientific Center for Radiation Medicine, Melnikova str., 53, Kiev (Ukraine); Simon, Steven L. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 6120 Executive Boulevard, Bethesda, MD (United States)], E-mail: ssimon@mail.nih.gov

2007-07-15

160

Tooth loss and obstructive sleep apnoea  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Complete tooth loss (edentulism produces anatomical changes that may impair upper airway size and function. The aim of this study was to evaluate whether edentulism favours the occurrence of obstructive sleep apnoea (OSA. Methods Polysomnography was performed in 48 edentulous subjects on two consecutive nights, one slept with and the other without dentures. Upper airway size was assessed by cephalometry and by recording forced mid-inspiratory airflow rate (FIF50. Exhaled nitric oxide (eNO and oral NO (oNO, were measured as markers of airway and oropharyngeal inflammation. Results The apnoea/hypopnoea index (AHI without dentures was significantly higher than with dentures (17·4 ± 3·6 versus 11·0 ± 2·3. p = 0·002, and was inversely related to FIF50 (p = 0·017 and directly related to eNO (p = 0·042. Sleeping with dentures, 23 subjects (48% had an AHI over 5, consistent with OSA, but sleeping without dentures the number of subjects with abnormal AHI rose to 34 (71%. At cephalometry, removing dentures produced a significant decrease in retropharyngeal space (from 1·522 ± 0·33 cm to 1·27 ± 0·42 cm, p = 0·006. Both morning eNO and oNO were higher after the night slept without dentures (eNO 46·1 ± 8·2 ppb versus 33·7 ± 6·3 ppb, p = 0·035, oNO 84·6 ± 13·7 ppb versus 59·2 ± 17·4 ppb, p = 0·001. Conclusion These findings suggest that complete tooth loss favours upper airway obstruction during sleep. This untoward effect seems to be due to decrease in retropharyngeal space and is associated with increased oral and exhaled NO concentration.

Gai Valerio

2006-01-01

 
 
 
 
161

Tooth structure and fracture strength of cavities  

DEFF Research Database (Denmark)

This study evaluated, in vitro, the loss of tooth substance after cavity preparation for direct and indirect restorations and its relationship with fracture strength of the prepared teeth. Sixty sound human maxillary first premolars were assigned to 6 groups (n=10). MOD direct composite cavities (Groups I, II and III) and indirect inlay cavities (Groups IV, V and VI) were prepared maintaining standardized dimensions: 2-mm deep pulpal floors, 1.5-mm wide gingival walls and 2-mm high axial walls. Buccolingual width of the occlusal box was established at 1/4 (Groups I and IV), 1/3 (Groups II and V) or 1/2 (Groups III and VI) of the intercuspal distance. Teeth were weighed (digital balance accurate to 0.001 g) before and after preparation to record tooth substance mass lost during cavity preparation. The prepared teeth were submitted to occlusal loading to determine their fracture strength using a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey test (alpha= 0.05). 1/4-inlay cavities had higher percent mean mass loss (9.71%) than composite resin cavities with the same width (7.07%). 1/3-inlay preparations also produced higher percent mean mass loss (13.91%) than composite resin preparations with the same width (10.02%). 1/2-inlay cavities had 21.34% of mass loss versus 16.19% for the 1/2-composite resin cavities. Fracture strength means (in kgf) were: GI = 187.65; GII = 143.62; GIII = 74.10; GIV = 164.22; GV = 101.92; GVI = 50.35. Statistically significant difference (p

Mondelli, José; Sene, Fábio

2007-01-01

162

Morphological characterization of the tooth/adhesive interface  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este estudo teve o objetivo de observar a morfologia da interface dente-restauração de diferentes sistemas adesivos em cavidades MOD, por microscopia eletrônica de varredura (MEV). A hipótese do estudo foi de que a morfologia da interface adesiva poderia variar nas diferentes regiões da cavidade MOD [...] , para algum dos 3 sistemas adesivos estudados. Preparos tipo MOD foram confeccionados em 12 terceiros molares humanos hígidos e restaurados com resina composta Filtek Z250 e os seguintes sistemas adesivos: ABF (n=4), Clearfil SE Bond (n=4) (sistemas adesivos autocondicionantes) e Single Bond (n=4) (sistema adesivo de condicionamento ácido total). Após 24 h de armazenamento em água destilada a 37ºC, os dentes foram secionados e preparados para MEV. A morfologia da interface de união variou com o sistema adesivo e com a região analisada. A hipótese do estudo foi aceita, pois a morfologia da interface de união refletiu as características do substrato dental e dos sistemas adesivos testados. Abstract in english The purpose of this study was to assess the morphological characteristics of the tooth/adhesive interface using different adhesive systems in MOD restorations under scanning electron microscopy (SEM). The tested hypothesis was that the morphology of the bonding interface would vary in different area [...] s of MOD restorations for the three adhesive systems. MOD cavities were prepared in 12 sound extracted human third molars and restored with Filtek Z250 composite resin and one of the following adhesive systems: Experimental ABF (n=4), Clearfil SE Bond (n=4) self-etching primers and Single Bond etch-and-rinse adhesive system (n=4). After 24-h storage in distilled water at 37ºC, teeth were sectioned and prepared for SEM. The interfacial morphology varied depending on the adhesive system and also on the evaluated area. The null hypothesis was accepted because the morphology of the tooth/adhesive interface reflected the characteristics of both the dental substrate and the adhesive systems.

Sandra Kiss, Moura; José Fortunato Ferreira, Santos; Rafael Yagüe, Ballester.

163

Tooth resorption in the Swedish Eurasion lynx (Lynx lynx).  

Science.gov (United States)

The etiology of tooth resorption in the domestic cat remains unknown. The high prevalence and progressive nature of the disease complicates defining healthy control groups. In order to evaluate the possible influence of various life style changes on the prevalence of tooth resorption, healthy control groups are a prerequisite. This paper presents a prevalence study for tooth resorption in a free-ranging wild felidae population. Skulls from 46 free-ranging Eurasian lynx (Lynx lynx) were examined. The age of the animals had previously been estimated based on cementum annuli in the maxillary right canine tooth. The dental examination included both dental probing and radiographic imaging. Complicated fractures of the canine teeth were found in 9/46 (19.5%) skulls. In one fractured canine, apical root resorption and periapical lucency was detected. The root resorption was attributed to inflammatory resorption as a consequence of the initial dental trauma and necrotic pulp. No signs of tooth resorption were found in the remaining teeth. Supernumerary roots were detected in 18/46 skulls (39.1 %). Supernumerary "peg" teeth caudal to the mandibular first molar tooth were detected in 6/46 (13.0%) skulls. Although further studies on dental ultra-structure are needed, the Swedish Eurasian lynx may, in the future, be useful as a healthy comparative model for studies on the etiopathogenesis of tooth resorption in the domestic cat. PMID:21322429

Pettersson, Ann

2010-01-01

164

Secondary induction and the development of tooth nerve supply.  

Science.gov (United States)

During embryogenesis, dental trigeminal axon navigation and patterning in the developing tooth take place in a highly spatio-temporally directed manner that is tightly linked to tooth morphogenesis and cell differentiation. Tooth formation is regulated by sequential and reciprocal tissue interactions between dental epithelium and neural crest-derived ectomesenchymal cells. This odontogenic secondary induction is mediated by signal molecules of different conserved families. Recent molecular and experimental data have provided evidence that local instructive signaling from the early odontogenic epithelium also controls dental axon navigation in the dental mesenchyme. In this review, we discuss recent molecular data regarding tooth formation and innervation and the putative role of the secondary induction in coordinating these two developmental processes. Importantly, because it has not yet been shown that the interactions that regulate tooth innervation include signaling to the dental epithelium and that they are reciprocal, it remains to be demonstrated that secondary induction controls the establishment of tooth nerve supply. Moreover, the key question of which molecule(s), if any, integrate tooth morphogenesis and the development of dental sensory trigeminal innervation remains to be answered. PMID:18413271

Luukko, Keijo; Moe, Kyaw; Sijaona, Angelica; Furmanek, Tomasz; Hals Kvinnsland, Inger; Midtbø, Marit; Kettunen, Päivi

2008-01-01

165

BMP4 signaling mediates Zeb family in developing mouse tooth.  

Science.gov (United States)

Tooth morphogenesis is regulated by sequential and reciprocal interaction between oral epithelium and neural-crest-derived ectomesenchyme. The interaction is controlled by various signal molecules such as bone morphogenetic protein (BMP), Hedgehog, fibroblast growth factor (FGF), and Wnt. Zeb family is known as a transcription factor, which is essential for neural development and neural-crest-derived tissues, whereas the role of the Zeb family in tooth development remains unclear. Therefore, this study aimed to investigate the expression profiles of Zeb1 and Zeb2 during craniofacial development focusing on mesenchyme of palate, hair follicle, and tooth germ from E12.5 to E16.5. In addition, we examined the interaction between Zeb family and BMP4 during tooth development. Both Zeb1 and Zeb2 were expressed at mesenchyme of the palate, hair follicle, and tooth germ throughout the stages. In the case of tooth germ at the cap stage, the expression of Zeb1 and Zeb2 was lost in epithelium-separated dental mesenchyme. However, the expression of Zeb1 and Zeb2 in the dental mesenchyme was recovered by Bmp4 signaling via BMP4-soaked bead and tissue recombination. Our results suggest that Zeb1 and Zeb2, which were mediated by BMP4, play an important role in neural-crest-derived craniofacial organ morphogenesis, such as tooth development. PMID:22350174

Shin, Jeong-Oh; Kim, Eun-Jung; Cho, Kyoung-Won; Nakagawa, Eizo; Kwon, Hyuk-Jae; Cho, Sung-Won; Jung, Han-Sung

2012-06-01

166

Safety issues of tooth whitening using peroxide-based materials.  

Science.gov (United States)

In-office tooth whitening using hydrogen peroxide (H?O?) has been practised in dentistry without significant safety concerns for more than a century. While few disputes exist regarding the efficacy of peroxide-based at-home whitening since its first introduction in 1989, its safety has been the cause of controversy and concern. This article reviews and discusses safety issues of tooth whitening using peroxide-based materials, including biological properties and toxicology of H?O?, use of chlorine dioxide, safety studies on tooth whitening, and clinical considerations of its use. Data accumulated during the last two decades demonstrate that, when used properly, peroxide-based tooth whitening is safe and effective. The most commonly seen side effects are tooth sensitivity and gingival irritation, which are usually mild to moderate and transient. So far there is no evidence of significant health risks associated with tooth whitening; however, potential adverse effects can occur with inappropriate application, abuse, or the use of inappropriate whitening products. With the knowledge on peroxide-based whitening materials and the recognition of potential adverse effects associated with the procedure, dental professionals are able to formulate an effective and safe tooth whitening regimen for individual patients to achieve maximal benefits while minimising potential risks. PMID:23846062

Li, Y; Greenwall, L

2013-07-01

167

Tooth bleaching--a critical review of the biological aspects  

DEFF Research Database (Denmark)

Present tooth-bleaching techniques are based upon hydrogen peroxide as the active agent. It is applied directly, or produced in a chemical reaction from sodium perborate or carbamide peroxide. More than 90% immediate success has been reported for intracoronal bleaching of non-vital teeth, and in the period of 1-8 years' observation time, from 10 to 40% of the initially successfully treated teeth needed re-treatment. Cervical root resorption is a possible consequence of internal bleaching and is more frequently observed in teeth treated with the thermo-catalytic procedure. When the external tooth-bleaching technique is used, the first subjective change in tooth color may be observed after 2-4 nights of tooth bleaching, and more than 90% satisfactory results have been reported. Tooth sensitivity is a common side-effect of external tooth bleaching observed in 15%-78% of the patients, but clinical studies addressing the risk of other adverse effects are lacking. Direct contact with hydrogen peroxide induced genotoxic effects in bacteria and cultured cells, whereas the effect was reduced or abolished in the presence of metabolizing enzymes. Several tumor-promoting studies, including the hamster cheek pouch model, indicated that hydrogen peroxide might act as a promoter. Multiple exposures of hydrogen peroxide have resulted in localized effects on the gastric mucosa, decreased food consumption, reduced weight gain, and blood chemistry changes in mice and rats. Our risk assessment revealed that a sufficient safety level was not reached in certain clinical situations of external tooth bleaching, such as bleaching one tooth arch with 35% carbamide peroxide, using several applications per day of 22% carbamide peroxide, and bleaching both arches simultaneously with 22% carbamide peroxide. The recommendation is to avoid using concentrations higher than 10% carbamide peroxide when one performs external bleaching. We advocate a selective use of external tooth bleaching based on high ethical standards and professional judgment.

Dahl, J E; Pallesen, Ulla

2003-01-01

168

Tooth loss prevalence among cardiac males and females  

International Nuclear Information System (INIS)

Objective of study was to observe differences of tooth loss prevalence in males and females with Cardiac diseases Poor oral health, tooth loss and periodontal diseases have been reported to be associated with coronary heart diseases. Studies report gender differences in prevalence of cardiac diseases and tooth loss. This paper presents gender differences of tooth loss in cardiac patients of a cardiac hospital of Lahore, Pakistan. Methodology: Age matched Cardiac males and females attending OPD of the Punjab Institute of Cardiology (PIC), Lahore were included in the study. Personal and health-related information were questioned and noted. Oral examination was performed for recording of missing teeth. 1200 CHD study subjects with age-range of 30 to 80 years were enrolled for study. 1045 age matched, 766 (73.30%) males and 279 (26.70%) females were examined for tooth loss. 852 (81.53%) genders had at least one tooth missing. 599 (78.19) males and 253 (90.68%) females were observed with mean tooth loss of 7.5 (SD 8.720) and 11.15 (SD 10.375)respectively statistical association among them was also significant (P= 0.000) with OR of 2.339. More subjects (76.29%) showed a loss of 1-15 teeth that I was also significant among males and females. Tooth loss was significant in age groups of 41-50 years (P=0.001) and 51-60 years (P=0.000) Gender differences of tooth loss prevalence among CHD Subjects were significant with more risk for males as compared to females. (author)

169

Functional constraints on tooth morphology in carnivorous mammals  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The range of potential morphologies resulting from evolution is limited by complex interacting processes, ranging from development to function. Quantifying these interactions is important for understanding adaptation and convergent evolution. Using three-dimensional reconstructions of carnivoran and dasyuromorph tooth rows, we compared statistical models of the relationship between tooth row shape and the opposing tooth row, a static feature, as well as measures of mandibular motion during chewing (occlusion, which are kinetic features. This is a new approach to quantifying functional integration because we use measures of movement and displacement, such as the amount the mandible translates laterally during occlusion, as opposed to conventional morphological measures, such as mandible length and geometric landmarks. By sampling two distantly related groups of ecologically similar mammals, we study carnivorous mammals in general rather than a specific group of mammals. Results Statistical model comparisons demonstrate that the best performing models always include some measure of mandibular motion, indicating that functional and statistical models of tooth shape as purely a function of the opposing tooth row are too simple and that increased model complexity provides a better understanding of tooth form. The predictors of the best performing models always included the opposing tooth row shape and a relative linear measure of mandibular motion. Conclusions Our results provide quantitative support of long-standing hypotheses of tooth row shape as being influenced by mandibular motion in addition to the opposing tooth row. Additionally, this study illustrates the utility and necessity of including kinetic features in analyses of morphological integration.

Smits Peter D

2012-08-01

170

[A case of injured unerupted permanent tooth in a child].  

Science.gov (United States)

Children with trauma visit frequently the department of oral and maxillofacial surgery. The treatment for injured permanent teeth is different from that for injured deciduous teeth. We have experienced a case of a 9-year-old boy with an injured unerupted immature permanent tooth with tooth crown fracture. When the tooth erupted gradually, fractured pieces were removed three times, and indirect pulp capping was performed. Three years after the injury eruption was almost completed and pulp was alive, even though the dental roentgenograph showed obliteration of the crown pulp cavity. PMID:8522895

Suganuma, T; Tanaka, N; Amagasa, T; Miyashin, M; Hashimoto, Y

1995-09-01

171

Axis Inhibition Protein 2 (AXIN2) Polymorphisms and Tooth Agenesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tooth agenesis is a common congenital disorder that affects almost 20 percent of the world’s population. A number of different genes have been shown to be associated with cases of tooth agenesis including AXIN2, IRF6, FGFR1, MSX1, PAX9, and TGFA. Of particular interest is AXIN2, which was linked to two families segregating oligodontia and colorectal cancer. We studied two collections of families affected with tooth agenesis and tested them for association with AXIN2. Significant association...

Callahan, N.; Modesto, A.; Meira, R.; Seymen, F.; Patir, A.; Vieira, Ar

2009-01-01

172

Actinomyces endogenous endophthalmitis in a cat following multiple dental extractions.  

Science.gov (United States)

An 8-year-old, brachycephalic, mixed breed cat underwent full mouth tooth extractions for the treatment of tooth root abscessation. Subsequently, the cat developed anterior uveitis refractory to topical therapy that eventually necessitated enucleation. Actinomyces species were isolated from both the tooth root abscesses and the anterior chamber after enucleation. Histopathology of the enucleated eye revealed panophthalmitis with abundant intralesional bacteria morphologically consistent with Actinomyces. Between the time of tooth root extraction and enucleation (20 weeks), the cat was diagnosed with hyperthyroidism and treated with oral steroids for inflammatory bowel syndrome. We believe this report represents a rare case of endogenous endophthalmitis secondary to dental disease, possibly precipitated by concurrent immunosuppression. PMID:23281798

Westermeyer, Hans D; Ward, Daniel A; Whittemore, Jacqueline C; Lyons, Jeremiah A

2013-11-01

173

About Kids' Teeth: Baby Tooth Decay is Real  

Medline Plus

Full Text Available ... baby teeth. Keep Baby’s Gums and Teeth Clean Begin cleaning your baby's mouth during the first few ... What Are Cavities? Causes of Decay Tooth decay begins when cavity-causing bacteria is passed to an ...

174

About Kids' Teeth: Baby Tooth Decay is Real  

Medline Plus

Full Text Available ... times a day with a fluoride toothpaste for kids 2 and older. Learn about Thumb Sucking and ... that are about to arrive. Learn about Preventing Kids' Tooth Decay 12 – 17 Years Old Cavities ...

175

Retrospective individual dosimetry using EPR of tooth enamel  

International Nuclear Information System (INIS)

The results of joint investigations (in the framework of ECP-10 program) aimed on the improvement of the sensitivity and accuracy of the procedure of dose measurement using tooth enamel EPR spectroscopy are presented. It is shown, what the sensitivity of method may be increased using special physical-chemical procedure of the enamel samples treatment, which leads to the reducing of EPR signal of organic components in enamel. Tooth diseases may have an effect on radiation sensitivity of enamel. On the basis of statistical analysis of the results of more then 2000 tooth enamel samples measurements it was shown, what tooth enamel EPR spectroscopy gives opportunity to register contribution into total dose, which is caused by natural environmental radiation and by radioactive contamination. EPR response of enamel to ultraviolet exposure is investigated and possible influences to EPR dosimetry is discussed. The correction factors for EPR dosimetry in real radiation fields are estimated

176

Relationship between natural tooth shade and skin colour.  

Science.gov (United States)

The purpose of this study was to assess the correlation of skin colour and tooth shade. One hundred and twenty six individuals aging between 18 to 25 years participated in this study. Colour of the maxillary central incisors was examined by VITA easy shade. Tooth shades were assigned to four ordinal values. Nivea Beauty Protect Foundation shade sample was used as a guide to assess facial skin colour Shin colours were also assigned to four ordinal values. Spearman test revealed that there was a significant relationship between tooth shade and skin colour Total co-relation factor was 51.6% (p <0 .01). Co-relation factors were 57% for women and 27% for men (p <0 .01). The highest tooth shade prevalence belonged to the second group and the highest skin colour prevalence was also in the second skin colour group. PMID:23888526

Nourbakhsh, M; Mousavinejad, N; Adli, A R; Harati, M

2013-06-01

177

Restoring Esthetics in Traumatic Tooth Fractures with all Ceramic Restorations  

Directory of Open Access Journals (Sweden)

Full Text Available Earlier Metal ceramic crowns were the restorations of choice in the management of traumatic tooth fractures. However, the inherent drawbacks of metal ceramic restorations and the development of newer all ceramic alternatives have resulted in superior esthetic and functional management of these clinical situations. The following case series describes the management of traumatic tooth fractures with Zirconia based all ceramic restorations following endodontic therapy.

Mainak Kanti Saha, *Superna Ganguly Saha

2012-01-01

178

Moxel: A molar tooth voxel model for dosimetric studies  

Energy Technology Data Exchange (ETDEWEB)

Stylized numerical models of the tooth are usually employed in qualification procedure related to Electronic Paramagnetic Resonance in long-term accidental contamination dose reconstruction. In this work a voxel model was developed from the microCT image data set of a human non contaminated molar tooth. A stylized model, reproducing the characteristics of the voxel model, was also created in order to investigate the level of accuracy that can be obtained in this kind of study.

Ferrari, P., E-mail: paolo.ferrari@enea.i [ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, ION-IRP, Radiation Protection Institute, 16 Via dei Colli, 40136 Bologna (Italy); Gualdrini, G. [ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, ION-IRP, Radiation Protection Institute, 16 Via dei Colli, 40136 Bologna (Italy); Fattibene, P. [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00161 Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Gruppo Collegato Sanita, Viale Regina Elena 299, I-00161 Roma (Italy); Veronese, I. [Universita degli Studi di Milano, Dipartimento di Fisica, Via Celoria 16, 20133 Milano (Italy); INFN, Sezione di Milano, Via Celoria 16, 20133 Milano (Italy)

2010-02-15

179

Single tooth tells us the date of birth.  

Science.gov (United States)

The atmospheric carbon-14 ((14)C) concentration remained relatively stable until 1955, but then rapidly increased after 1955 by nuclear bomb tests, peaked in 1963, and decreased thereafter. Recently, Spalding et al. proposed epoch-making method for determining date of birth (DOB) using the tooth enamel (14)C incorporated during enamel formation. However, because the (14)C level analyzed in one tooth gives two possible age ranges (up-slope or down-slope of the bomb curve), a variety of teeth that formed in different periods are required for estimating DOB in this method. Enamel formation in a tooth moves from the incisal (occlusal) side to the cervical side. Taking advantage of this characteristic, we have first succeeded in specifying the age range from only single tooth by measuring (14)C in the incisal (occlusal) and cervical regions of the enamel separately. To date, no method of determining DOB or age estimation from single tooth enamel has been made. Furthermore, this method of dividing tooth into smaller parts could be useful for producing a more accurate DOB. Our new method is a powerful tool for identification when we can use only extremely few specimens in forensic casework. PMID:20953875

Kondo-Nakamura, Mihoko; Fukui, Kenji; Matsu'ura, Shuji; Kondo, Megumi; Iwadate, Kimiharu

2011-11-01

180

Is there a link between ovarian cancer and tooth agenesis?  

Science.gov (United States)

An epidemiologic study from the year 2008 found a highly significant increase of congenital tooth agenesis in women with ovarian cancer suggesting that a common genetic etiology may predispose women to both conditions. The finding was reminiscent of a previously described family harboring an AXIN2 mutation which could be shown to segregate with both the tooth agenesis and the predisposition to colon cancer transmitted in this family. Since tooth agenesis as a marker for susceptibility to ovarian cancer would be of great relevance to both oncologists and women with inborn missing teeth, the relationship between the two disorders requires a thorough assessment. We examined DNA samples from the ovarian cancer patients who participated in the original study, to look for a possible genetic connection between their ovarian malignancies and tooth agenesis. MSX1, PAX9, AXIN2, EDA, WNT10A, BARX and BRCA1 genes were selected for sequence analysis as they may cause tooth agenesis, are expressed in the female reproductive system, and/or are involved in tumorigenesis in general or specifically in the ovary. Our study revealed evidence that one half of the dually affected patients had an independent causation of the two conditions, thus reducing the previously estimated ovarian cancer risk for women with congenital tooth agenesis quite significantly. PMID:24631698

Bonds, John; Pollan-White, Sarah; Xiang, Lilin; Mues, Gabriele; D'Souza, Rena

2014-04-01

 
 
 
 
181

Anterior tooth morphology and its effect on torque.  

Science.gov (United States)

This study was undertaken to determine the variation in crown-root angle (CRA) of the upper incisors and canines as well as the variation in their labial contour. In addition, the influence of the variability of the labial contour and of different bracket heights on torque was evaluated. Proximal radiographs were taken of 160 extracted maxillary teeth (81 incisors and 79 canines). They were digitized and analysed with Jasc Paint Shop Pro 7TM and Mathcad 2001 Professional. The incisal edge, the centre of the cemento-enamel junction (CEJ), and the root apex were digitized to define the crown and root long axis. For all teeth the CRA was measured. At several heights of the labial surface a tangent was determined, enabling measurement of the inclination of the labial surface. The CRA had great variability, ranging from 167 to 195 degrees for the canines (mean value 183 degrees) and from 171 to 195 degrees for the incisors (average 184 degrees). The mean inclinations of the labial surfaces for the incisors varied greatly. Between 4 and 4.5 mm from the incisal edge the standard deviations (SD) were the smallest and between 2 and 4.5 mm from the incisal edge the labial surface angle differed by approximately 10 degrees. For the canines the mean inclinations of the buccal surface also varied. This angle differed by around 10 degrees between 2 and 4.5 mm from the incisal edge, but the SD were much larger than for the incisors. It can be concluded that placement of a bracket on a tooth at varying heights, still within a clinically acceptable range, results in important differences in the amount of root torque. PMID:15947225

van Loenen, M; Degrieck, J; De Pauw, G; Dermaut, L

2005-06-01

182

Histology of tooth attachment tissues and plicidentine in Varanus (Reptilia: Squamata), and a discussion of the evolution of amniote tooth attachment.  

Science.gov (United States)

Few recent studies have examined the histological basis for tooth attachment in squamates. In the past few years, a surge of interest in this topic has led to the intriguing suggestion that the major tissues derived from the tooth germ (enamel, dentine, cementum and alveolar bone), are conservative and are present in all amniotes. In this study, we describe the histology and development of the tooth attachment complex in Varanus rudicollis, the rough-neck monitor. We provide the first published evidence for the role of cementum and alveolar bone in tooth attachment in varanoid lizards. In Varanus, cementum is deposited on the external surface of the tooth root as well as at the base of the tooth, where it plays a role in the attachment of the tooth to the jawbone. Alveolar bone is also involved in tooth ankylosis. Our results support the hypothesis that the major tooth germ tissues are found in all amniotes. We provide insights into the structure and development of plicidentine, defined as infolding of the dentine around the tooth base. This feature is unique to varanoids among extant tetrapods and is the third tissue implicated in tooth attachment in Varanus. Plicidentine develops asymmetrically along the labial-lingual axis of a tooth. Varanus is characterized by the presence of both primary and higher-order lamellae, which anastomose to form a honeycomb-like surface that then interacts with the more basal attachment tissues. PMID:21618268

Maxwell, Erin E; Caldwell, Michael W; Lamoureux, Denis O; Budney, Lisa A

2011-10-01

183

Enfermedad de Charcot Marie Tooth en un niño / Charcot-Marie-Tooth disease in a child  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish Se presenta el caso clínico de un niño de 7 años de edad con enfermedad de Charcot Marie Tooth, atendido en el Servicio de Rehabilitación del Hospital Infantil Norte Docente "Dr. Juan de la Cruz Martínez Maceira" de Santiago de Cuba para recibir tratamiento rehabilitador. Luego del programa terapéut [...] ico aplicado el paciente mejoró el trofismo y la fuerza muscular, disminuyeron las deformidades del pie y ocurrieron importantes cambios en la marcha, de modo que la rehabilitación oportuna evitó el tratamiento quirúrgico. Abstract in english The case of a 7 year-old boy with Charcot- Marie-Tooth disease, who was attended at the Rehabilitation Department of "Dr. Juan de la Cruz Martínez Maceira" Northern Teaching Children Hospital in Santiago de Cuba for rehabilitation treatment is reported. After receiving a therapeutic program the pati [...] ent improved his muscle strenght and trophism, foot deformities decreased and significant changes occurred in gait, so that timely rehabilitation prevented surgical treatment.

Teresa, Vidal Pérez; Katiuska, Ragolta Mógrave; Hilda Alicia, Jhones Cabrales; Pastor, Perdomo Veranes; Manuel, Uriarte Gómez.

184

Amery Ice Shelf's 'Loose Tooth' Gets Looser  

Science.gov (United States)

The Amery Ice Shelf is an important dynamic system responsible for draining about 16% of the grounded East Antarctic ice sheet through only 2% of its coastline. Most of the mass input to the system occurs from the Lambert and several other glaciers. Mass loss from the system occurs through basal melting and iceberg calving. These images from the Multi-angle Imaging SpectroRadiometer (MISR) portray the ice shelf front on October 6, 2001 (top) and September 29, 2002 (bottom), and illustrate changes that took place over the year elapsed between the two views.Two longitudinal rifts, oriented roughly parallel to the direction of ice flow and measuring about 25 and 15 kilometers in length, are apparent near the seaward edge of the ice shelf. Between them, a transverse fracture extends eastward from the base of the western rift. This rift system is colloquially named the Amery 'loose tooth.' Over the course of the one-year interval between these two MISR images, the ice front has advanced approximately 1.6 - 1.7 kilometers, and the transverse fracture and a three-way fissure at the juncture of the rifts have widened. When the transverse fracture eventually reaches the eastern rift, a large iceberg (25 kilometers x 25 kilometers) will be released.These false-color multi-angle composites combine red-band data from MISR's 60o forward, nadir, and 60o aftward viewing cameras, displayed as red, green and blue, respectively. Different colors represent angular reflectance variations. Since generally smooth surfaces predominantly forward-scatter sunlight, these appear in shades of blue. Rough surfaces tend to backward-scatter sunlight, and these appear in shades of red or orange. Low clouds appear bright purple, since they exhibit both forward and backward-scattering. Using this technique, textural variations among ice types are revealed, and clouds can be easily distinguished from ice. Illumination conditions on the two dates are nearly identical.Understanding the 'normal' frequency of calving events from a particular ice shelf is necessary before it can be determined whether calving rates are changing. As part of an effort to determine the normal rate of ice flow and iceberg calving events, the Amery Ice Shelf front has been monitored by various remote sensing instruments for many years. The Amery Ice Shelf is currently considered to be about two-thirds of the way through a calving cycle. The last major calving event occurred in the early 1960's, when a massive iceberg (measuring about 140 kilometers x 70 kilometers) was released.The Amery 'loose tooth' is the subject of a joint field experiment during the 2002 austral summer, partially funded by NASA and undertaken by the Scripps Institution of Oceanography and the Australian Antarctic Division. The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 9579 and 14807. The panels cover an area of about 204 kilometers x 110 kilometers, and utilize data from blocks 146 to 147 within World Reference System-2 paths 127 and 128, respectively. Data from the two orbital paths have been remapped to identical polar projections, and were cropped to include the same geographic area.MISR was built and is managed by NASA's Jet Propulsion Laboratory,Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center,Greenbelt, MD. JPL is a division of the California Institute of Technology.

2002-01-01

185

Immunolocalization of Alk8 during replacement tooth development in zebrafish.  

Science.gov (United States)

The novel type I transforming growth factor-beta (TGF-beta) family member receptor Alk8 was previously identified in a degenerate RT-PCR screen for zebrafish type I and II TGF-beta family member receptors. Functional analyses revealed that Alk8 acts through Bmp signaling pathways in early embryonic dorsoventral patterning, in neural crest cell specification, and in patterning and differentiation of neural crest cell-derived pharyngeal arch cartilages. In addition, Alk8 forms active signaling complexes with TGF-beta1 and the TGF-beta RII receptor, suggesting that Alk8 mediates cross talk between Bmp and TGF-beta subfamily members. In this study, immunohistochemical analysis was performed on zebrafish aged 2 days postfertilization to 1 year, revealing immunolocalization of Alk8 to tissues of the tooth-bearing ceratobranchial 5 (cb5) arch including dental epithelial and mesenchymal tooth tissues of developing primary and replacement teeth, mucous-producing crypt epithelium, keratinized bite plate, and developing taste buds. These results suggest roles for Alk8 in patterning tooth-bearing pharyngeal epithelium, in the initiation of tooth development, in odontoblast and ameloblast differentiation, and in osteoblast maturation. The ability for zebrafish to continuously form teeth throughout their lives allows for the comparison of Alk8 expression in both primary and replacement tooth development, revealing identical Alk8 expression profiles. This study advances our current understanding of the functions of Alk8, particularly with respect to primary and replacement tooth formation, reveals additional roles for Alk8 in dental epithelial patterning and in odontoblast, ameloblast and osteoblast differentiation, and demonstrates the utility of the zebrafish as a model for primary and replacement tooth development. PMID:14745232

Perrino, Michael A; Yelick, Pamela C

2004-01-01

186

Comprehensive intermaxillary tooth width proportion of Bangkok residents  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Proper occlusion depends on the correct width ratio between upper and lower teeth, known as Bolton's ratio. In fact, this ratio can be calculated for each pair of teeth from the central incisor to the first permanent molar. This set of ratios, known as comprehensive cumulative percentage ratios (CPR [...] s), can be used not only to determine which tooth or teeth have a tooth width discrepancy, but can also enable the partial graphical analysis of tooth width discrepancy when there is agenesis of certain permanent teeth. Although CPRs have been calculated for Caucasians, tooth width is known to vary depending on racial origin. Therefore, a test of differences between racial groups should be carried out. If these ratios of the Caucasians and Bangkokians are significantly different, the ratio of the Bangkokians is recommended. The objective of this study was to measure tooth size disproportion for Thai patients and to calculate a corresponding set of CPRs. Thirty-seven pairs of dental models were made from a group of Bangkok residents with normal occlusion. Mesiodistal tooth width was measured for each model. The intra- and inter-examiner measurement errors were ascertained as insignificant (p > 0.05). CPRs were then calculated and compared to those derived from other studies. Ten of thirteen CPRs were significantly different from corresponding values derived from Caucasians. We conclude that tooth width ratios vary between different racial groups, and therefore that these should be calculated specifically for each patient racial group.

Somchai, Manopatanakul; Narumon, Watanawirun.

2011-04-01

187

Experimental Investigation of Sprocket Tooth Form Effect on Dynamic Tension of Silent Chain  

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Full Text Available The study's aim was to get ANSI sprocket tooth profile and involute sprocket tooth profile for effects on dynamic tension of chains in the silent chain drive, and analyse and compare the advantages and disadvantages of the different tooth profiles to choose more practical tooth profile from the two sprockets. Current collector was used to test the dynamic tension when straight sprocket and involute sprocket engaged with the same silent chain. And experimental data measured were analyzed in the amplitude domain and frequency domain. Test results indicate that the probability of tension appearing in the different numerical size and power spectral densities of load in the different frequencies of the involute tooth form are better than of straight tooth form, which show that the involute sprocket has been good working properties. In addition, taking the advantages of involute tooth profile into account in the process, the involute tooth form is recommended in universal sprocket tooth form of the actual use.

Wei Sun

2012-04-01

188

Intake of dairy calcium and tooth loss among Danish men and women : Dairy calcium and tooth loss  

DEFF Research Database (Denmark)

OBJECTIVE: To investigate whether gender differences in tooth loss are influenced by caries risk and sources of dietary calcium intake. METHODS: This was a cohort study that included 432 Danish adults (30-60 y old) with information on dietary calcium intake in 1982 and 1983 and tooth loss from 1987 and 1988 through 1993 and 1994. Total calcium intake, estimated by a 7-d food record or a a diet history interview, was divided into dairy and non-dairy forms of calcium. RESULTS: In men, a 10-fold increase in dairy calcium intake was significantly associated with a decreased risk of tooth loss (incidence-rate ratio 0.32, 95% confidence interval 0.15-0.68) even after an adjustment for tooth count in 1987 and 1988, age, education, and civil status (model 1), smoking, alcohol consumption, sucrose intake, and use of vitamin and/or mineral supplements (model 2), time since last dental visit and the presence of oral dryness (model 3), and a high Lactobacillus count (model 4). In women, dairy calcium was not statistically associated with tooth loss in the crude and adjusted models (models 1 to 3). However, the association became highly significant once the Lactobacillus count was included in model 4 (incidence-rate ratio 0.25, 95% confidence interval 0.09-0.73). Non-dairy calcium was not associated with tooth loss in men and women in the fully adjusted models. CONCLUSION: Dietary calcium intake, particularly calcium from dairy products, seems to protect against loss of teeth in adult men and women. The previous gender differences found in the relation between calcium intake and tooth loss may be the result of differences in the caries risk between genders.

Adegboye, Amanda R A; Twetman, Svante

2011-01-01

189

Dento-Alveolar distraction osteogenesis using rigid intra-oral tooth borne distraction device  

Science.gov (United States)

Background: The aim of this clinical prospective study is to apply and evaluate an approach to reduce the overall orthodontic treatment time, by means of dentoalveolar distraction osteogenesis to achieve rapid canine retraction using an indigenously developed intra-oral tooth-borne distraction device. Materials & Methods: This study was carried out in the Department of Orthodontics and Dentofacial Orthopedics. Four patients selected for the purpose of Maxillary and/or Mandibular canine distraction with a rigid custom-made, intra-oral distraction device made of stainless steel and were scheduled for orthodontic treatment with bilateral first premolar extraction and then subsequent bilateral canine teeth distalization. Results: In all the patients the canine teeth moved distally and made contact with the second premolars within 14-16 days range after which they were kept passive, with the appliance for a week of consolidation. The amount of canine retraction was in 7-7.5mms range, in all the patients, in each of the four quadrants studied. Bodily movement, tipping and buccal flaring of the canine teeth were noticed in all the cases. Conclusion: Combination of newer orthodontic appliances and the principles of biomechanics to maintain the control over rapid tooth movement, rapid canine distalization using distraction osteogenesis awaits further development before routine application, of this innovative and exciting approach. How to cite the article: Nair A, Kumar JP, Venkataramana V, Yuvaraj A, Reddy VS, Kumar SK. Dento-Alveolar distraction osteogenesis using rigid intra-oral tooth borne distraction device. J Int Oral Health 2014;6(2):106-13. PMID:24876710

Nair, Arvind; Kumar, J Phani; Venkataramana, V; Yuvaraj, A; Reddy, V Sridhar; Kumar, S Kishore

2014-01-01

190

Success Rate of Formocresol Pulpotomy versus Mineral Trioxide Aggregate in Human Primary Molar Tooth  

Directory of Open Access Journals (Sweden)

Full Text Available Background: In spite of long time and broad use of formaldehyde derivates (Fixation agent in primary tooth pulp treatment, There is some concerns about these derivates such as variability, inconsistency success rate, mutagenicity, cytotoxicity, alergenicity, and some other potential health hazards of them. Therefore other alternative pulpotomy procedures like Bioactive glass (BAG, Glutaraldehyde (2%, Hydroxyappetite (HA, Bone dried freezed (BDF, ferric sulfate (15%, laser, Electrosurgery (ES, Bone Morphogenic proteins (BMP, recombinant protein-1 (RP1, and Mineral Trioxide Aggregate (MTA have been compared. The purpose of this clinical trial is to assess radiographic and clinical success rate of Formocresol (FC pulpotomy in compare with MTA in human primary molar teeth. Methods: 64 molars were pulpotomized equally and randomly with mineral trioxide Aggregate and Formocresol. Prior to trial, we defined a case as failure, when one or more of the events such as external root resorption, internal root resorption, periapical and furca lucency, pain, swelling, mobility, dental abscess, or early extraction appeared. Every treated tooth was defined as successful, if any noted evident was not shown. Results: Totally, 60 teeth treatment (92.2 percent were successful and 7.8 percent were failed. Failure and success rates for MTA group were 6.3 and 93.7 percent, respectively. Failure and success rates in FC group were 8.4 and 90.2 percent respectively. The difference between MTA and FC treatment methods was not significant (Fisher Exact test. Conclusion: Findings of this study show that mineral trioxide aggregate can be an alternative procedure for FC pulpotomy of primary tooth. Keywords: Mineral trioxide aggregate, formocresol, pulpotomy, success and failure rate.

S E Jabbarifar

2004-12-01

191

Effect of Multiple Adhesive Coating on Microshear Bond Strength to Primary Tooth Dentin  

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Full Text Available Objective: Multiple adhesive coating is a controversial topic, especially in primary dentition that should be clarified. We evaluated the effect of multiple consecutive adhesive resin coatings on the microshear bond strength (µSBS of composite resin to primary tooth dentin utilizing a filled (Adper Single Bond Plus and an unfilled (Adper Single Bond adhesive resin.Materials and Methods: Thirty extracted primary canines were randomly allocated into two groups based on the adhesive used. Dentin occlusal surfaces were exposed and further polished on 400, 600 and 800-grit silicon-carbide paper. The surfaces were divided into two halves in the labial-lingual orientation. After etching, the adhesives were used either in double coats, or four coats on the halves of the same tooth followed by air evaporation for each layer and finally light curing. Cylinders of composite were bonded to the dentin surfaces. After 24 h shear bond testing was evaluated by Bisco tensile tester. ANOVA, Student t test and paired t test were used for statistical analysis.Results: The mean (standard deviation for double coats or four coats in single bond were 31.99 (2.94 and 30.25 (2.69, while they were 29.18 (3.35 and 31.26 (2.07 in single bond plus, respectively. No significant differences were found between the double coated specimens and those receiving four coatings with both adhesives (p>0.05. Micro SBS values of Single Bond double coated specimens were significantly higher than Single Bond Plus (p=0.02. In four-coated specimens, there were no significant differences between Single Bond and Single Bond Plus (p=0.26.Conclusion: Applying four coats of adhesive did not improve the µSBS to primary tooth dentin.

Beheshteh Malekafzali Malekafzali

2013-01-01

192

Effect of several tooth-colored restorative materials on reinforcement of unsupported enamel  

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Full Text Available Introduction: Adhesive restorations properly transmit and distribute functional stresses at the bonding interface to tooth structures and have the potential to reinforce remaining weakened tooth structures after removal of extensive carious lesions. This study evaluated the effect of a number of adhesive restorative materials on reinforcing unsupported enamel. Materials and Methods: Seventy-five extracted sound maxillary premolars collected over 3 months and stored in 0.2% thymol solution received MOD cavities; the lingual cusps were reduced up to the pulp level. The specimens were divided into five groups (n=15. In group 1 (the positive control, dentinal tissue of the buccal wall was preserved. In other groups the buccal dentin was completely removed. In group 2 (the negative control, no restorative material was used to replace the lost dentin. The removed buccal dentin was replaced with composite resin, flowable composite resin and glass-ionomer in groups 3, 4 and 5, respectively. After thermocycling, the specimens were tested in an Instron universal testing machine. Data were analyzed with ANOVA and LSD test (a < 0.05. Results: The mean and standard deviations of fracture loads of the five groups were 122.97 ± 15.11, 44.71 ± 14.23, 78.32±17.58, 81.17 ± 19.53, and 85.33 ± 22.07 Newtons, respectively. One-way ANOVA revealed significant differences between the groups (p value = 0.00. There were significant differences in fracture loads between groups 1 and 2 and others (p value = 0.00. The difference in fracture loads between group 3 and 4 (p value = 0.678, groups 3 and 5 (p value = 0.344, and groups 4 and 5 (p value = 0.589 were not significant. Conclusion: It can be concluded that the three types of adhesive restorative materials in this study can reinforce unsupported enamel to a certain degree. Key words: Composite resin, Dental adhesives, Reinforcement, Tooth enamel.

Mohammadreza Malekipour

2012-01-01

193

The development of complex tooth shape in reptiles.  

Science.gov (United States)

Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development. PMID:24611053

Zahradnicek, Oldrich; Buchtova, Marcela; Dosedelova, Hana; Tucker, Abigail S

2014-01-01

194

Detecting Gear Tooth Fatigue Cracks in Advance of Complete Fracture  

Science.gov (United States)

Results of using vibration-based methods to detect gear tooth fatigue cracks are presented. An experimental test rig was used to fail a number of spur gear specimens through bending fatigue. The gear tooth fatigue crack in each test was initiated through a small notch in the fillet area of a tooth on the gear. The primary purpose of these tests was to verify analytical predictions of fatigue crack propagation direction and rate as a function of gear rim thickness. The vibration signal from a total of three tests was monitored and recorded for gear fault detection research. The damage consisted of complete rim fracture on the two thin rim gears and single tooth fracture on the standard full rim test gear. Vibration-based fault detection methods were applied to the vibration signal both on-line and after the tests were completed. The objectives of this effort were to identify methods capable of detecting the fatigue crack and to determine how far in advance of total failure positive detection was given. Results show that the fault detection methods failed to respond to the fatigue crack prior to complete rim fracture in the thin rim gear tests. In the standard full rim gear test all of the methods responded to the fatigue crack in advance of tooth fracture; however, only three of the methods responded to the fatigue crack in the early stages of crack propagation.

Zakrajsek, James J.; Lewicki, David G.

1996-01-01

195

Relation of Birth Weight with Time of First Deciduous Tooth  

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Full Text Available The deciduous teeth play a very important role in proper alignment, placing and occlusion of permanent teeth. Calcification of deciduous teeth begins during the fourth month of fetal life, and by the end of sixth month all of the deciduous teeth have begun calcification. Eruption date is variable and timing of eruption "runs in families". Delay of deciduous teeth eruption, especially the first teeth cause nutritional problem for infant and some worries for family. In this study we compare the time of eruption of first deciduous teeth in infant with their birth weight. A total of 148 infant who born at Shariati Hospital in Tehran in 2004- 2005 consecutively entered the study. Other data such as sex, birth weight, gestational age and time of first tooth eruption were collected. The mean birth weight was 3220 ± 420 grams. 5.5% of cases were less than 2500 grams and 19.9% were over 3500 grams. The patients were followed weekly since third month of birth till the time of their first tooth eruption and the data was analyzed. The mean age of eruption of first tooth was 7.68 ± 1.84 months. The results showed a reverse linear relationship between first deciduous tooth eruption and birth weight. So delayed tooth eruption may relate to birth weight.

Sajjadian Negar

2009-10-01

196

Prevalence of tooth wear among 16-year-old secondary school children in Kota Bharu, Kelantan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tooth wear is the non-carious loss of tooth tissue due to attrition, erosion and/or abrasion. The amount of wear that accelerates physiological tooth wear is referred as pathological tooth wear. This study aims to determine the prevalence and mean scores according to mouth quadrant of raw tooth wear (RTW) and pathological tooth wear (PTW) and investigate sex association with PTW among 16-year-old secondary school children in Kota Bharu, Kelantan. This cross-sectional study involves 688 partic...

Saerah, N. B.; Ismail, N. M.; Naing, L.; Ismail, A. R.

2006-01-01

197

Role of tooth elongation in promoting fracture resistance.  

Science.gov (United States)

A study is made of the role of tooth height on the resistance to side-wall longitudinal fracture under axial occlusal loading, building on earlier analyses for molar teeth with low dome-like ('bunodont') crown structures characteristic of primates and several other omnivorous mammals. The present study extends the analysis by considering molar teeth with an elongate columnar structure below the crown, more characteristic of grazing mammals. Extended finite element modeling is used to determine the evolution of longitudinal cracking, from initial growth to final failure. Experimental tests on sheep teeth confirm the predicted behavior of the longitudinal fracture mode, at least in its early stages. It is demonstrated that elongate tooth structures have a substantially increased resistance to longitudinal fracture, by restricting crack growth along the extended side walls. Biological implications concerning the adaptation of tooth structure to meet changes in the dietary habits of herbivores, and of some carnivores, are considered. PMID:22402152

Barani, Amir; Keown, Amanda J; Bush, Mark B; Lee, James J-W; Lawn, Brian R

2012-04-01

198

Electron microscopy analysis of different orthodontic brackets and their adhesion to the tooth enamel.  

Science.gov (United States)

This study proposed to evaluate the surface morphology of different types of orthodontic brackets and the characteristics of their adhesion to the tooth enamel. There have been taken into study six metallic, five ceramic and one polymeric bracket from different brands (Ormco, Lancer, Leone, Damon, 3M, Ultradent, American Orthodontics, Rocky Mountain). The surface base of the each bracket it have been ESEM analyzed using scanning electron microscope Phillips XL-30 ESEM. There have been investigated several parameters that have a potential influence of the bracket-bonding agent interface joint: chemical composition, roughness, surface morphology and wideness. After ESEM analysis, the same metallic and ceramic brackets have been afterwards collated on extracted teeth and subjected to mechanical tests. After the mechanical testing, the samples were once again ESEM investigated. All fractures occurred in the area of the adhesive system, recording adhesive fractures of the tooth-composite resin and composite-bracket, cohesive fractures and both. The metallic brackets surfaces that are optima for a good adhesion is that of a mesh sand blasted and acid etched. From the esthetic brackets, the ceramic ones are superior to polymeric ones regarding bonding to teeth. PMID:25178330

Ciocan, Delia Ioana; Stanciu, Drago?; Popescu, Manuela Anca; Miculescu, Florin; Plotog, Ioan; V?rzaru, Gauden?iu; Ciocan, Lucian Toma

2014-01-01

199

Expression of RANKL mRNA during Root Resorption Induced by Orthodontic Tooth Movement in Rats  

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Full Text Available Objective: Receptor activator for nuclear factor kappa B ligand (RANKL, which is alsocalled osteoclast differentiation factor, is an important regulatory factor in osteoclastmaturation. Knowledge of bone and cementum similarities and RANKL role in bone resorptionsuggests the possibility of a role for this protein in root resorption induced by orthodontictooth movement. The aim of this study is to examine the expression of RANKLmRNA during root resorption induced by orthodontic tooth movement in rats.Materials and Methods: In order to move maxillary right first molars mesially fixed Ni-Ticlosed coil springs (Dentaurum®-Germany were tightened to the teeth. Sample consistedof 20 male seven week old Wistar rats. For each animal, the contralateral tooth was usedas, an internal control. At day 21 the rats were sacrificed. Tissues from 10 rats were embeddedin paraffin for histologic examination. Scratched material from resorptive lacunaeon mesial sides of the roots of the other ten rats was used for extracting mRNA by RTPCR.Results: The histologic sections, analyzed histomorphometrically, showed a significantincrease in root resorption in the case group as compared to the control (p<0.001.Densitometric studies of RANKL mRNA expression band on gel electrophoresis showedsignificantly increased RANKL expression in the resorptive lacunae of the case group(p<0.001.Conclusion: This observation indicates increased RANKL

Massoud Seifi

2009-01-01

200

Effect of Orthodontic Tooth Movement on Gingival Crevicular Fluid Infiltration; a Preliminary Investigation  

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Full Text Available Objective: The gingival crevicular fluid (GCF is an inflammatory exudate found in the gingival sulcus. The forces exerted during orthodontic treatment cause distortion of the periodontal ligament (PDL extra-cellular matrix, resulting in some biological features that can lead to modification of both GCF volume and its components. The present study investigated the effect of orthodontic tooth movements, specifically canine retraction, on the volume of GCF exudate.Materials and Methods: Fourteen upper and lower canines of patients with different Angle classifications were selected for the study. After extraction of the first premolars, the canines were subjected to orthodontic distal retraction. GCF was sampled from mesial anddistal gingival crevices of each canine separately at baseline, 1 hour, 7 days, 14 days, 21 days, and 28 days after the application of the orthodontic distal retraction. GCF volume was determined by means of an electronic device.Results: GCF volume at tension sites was slightly greater after 21 and 28 days compared to other observation time points. At pressure sites, GCF volume was slightly greater after 28 days compared to other observation time points. None of the observed differences,however, was statistically significant (P>0.05.Conclusion: Orthodontic tooth movement, namely canine retraction, does not significantly increase the volume of GCF exudate. The slight increase in GCF volume could be due to a slight degree of gingival inflammation.

A. Dannan

2009-09-01

 
 
 
 
201

Systemic Antibiotics and Tooth Loss in Periodontal Disease  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Systemic antibiotics have been recommended for the treatment of destructive periodontal disease. Our goal was to relate antibiotic use for medical or dental reasons to subsequent tooth loss in a cohort of 12,631 persons with destructive periodontal disease. After adjustment for age, smoking, and other confounders, the dispensing of antibiotics for 1-13 days, 14-20 days, or 21 or more days was not associated with reduced tooth loss [Adjusted rate ratio (RR) = 1.0; 95% Confidence Interval (CI) ...

Cunha-cruz, J.; Hujoel, P. P.; Maupome, G.; Saver, B.

2008-01-01

202

Melatonin Effects on Hard Tissues: Bone and Tooth  

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Full Text Available Melatonin is an endogenous hormone rhythmically produced in the pineal gland under the control of the suprachiasmatic nucleus (SCN and the light/dark cycle. This indole plays an important role in many physiological processes including circadian entrainment, blood pressure regulation, seasonal reproduction, ovarian physiology, immune function, etc. Recently, the investigation and applications of melatonin in the hard tissues bone and tooth have received great attention. Melatonin has been investigated relative to bone remolding, osteoporosis, osseointegration of dental implants and dentine formation. In the present review, we discuss the large body of published evidence and review data of melatonin effects on hard tissues, specifically, bone and tooth.

Hong-Wen He

2013-05-01

203

Restoration of noncarious tooth defects by dentists in The Dental Practice-Based Research Network  

DEFF Research Database (Denmark)

The authors conducted a study to quantify the reasons for restoring noncarious tooth defects (NCTDs) by dentists in The Dental Practice-Based Research Network (DPBRN) and to assess the tooth, patient and dentist characteristics associated with those reasons.

Nascimento, Marcelle M; Gordan, Valeria V

2011-01-01

204

21 CFR 872.3900 - Posterior artificial tooth with a metal insert.  

Science.gov (United States)

... Posterior artificial tooth with a metal insert. 872.3900 Section 872.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3900 Posterior artificial tooth with a metal...

2010-04-01

205

Asymmetric extractions in orthodontics  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english INTRODUCTION: Extraction decisions are extremely important in during treatment planning. In addition to the extraction decision orthodontists have to choose what tooth should be extracted for the best solution of the problem and the esthetic/functional benefit of the patient. OBJECTIVE: This article [...] aims at reviewing the literature relating the advantages, disadvantages and clinical implications of asymmetric extractions to orthodontics. METHODS: Keywords were selected in English and Portuguese and the EndNote 9 program was used for data base search in PubMed, Web of Science (WSc) and LILACS. The selected articles were case reports, original articles and prospective or retrospective case-control studies concerning asymmetrical extractions of permanent teeth for the treatment of malocclusions. CONCLUSION: According to the literature reviewed asymmetric extractions can make some specific treatment mechanics easier. Cases finished with first permanent molars in Class II or III relationship in one or both sides seem not to cause esthetic or functional problems. However, diagnosis knowledge and mechanics control are essential for treatment success.

Camilo Aquino, Melgaço; Mônica Tirre de Souza, Araújo.

206

Asymmetric extractions in orthodontics  

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUCTION: Extraction decisions are extremely important in during treatment planning. In addition to the extraction decision orthodontists have to choose what tooth should be extracted for the best solution of the problem and the esthetic/functional benefit of the patient. OBJECTIVE: This article aims at reviewing the literature relating the advantages, disadvantages and clinical implications of asymmetric extractions to orthodontics. METHODS: Keywords were selected in English and Portuguese and the EndNote 9 program was used for data base search in PubMed, Web of Science (WSc and LILACS. The selected articles were case reports, original articles and prospective or retrospective case-control studies concerning asymmetrical extractions of permanent teeth for the treatment of malocclusions. CONCLUSION: According to the literature reviewed asymmetric extractions can make some specific treatment mechanics easier. Cases finished with first permanent molars in Class II or III relationship in one or both sides seem not to cause esthetic or functional problems. However, diagnosis knowledge and mechanics control are essential for treatment success.

Camilo Aquino Melgaço

2012-04-01

207

Effect of Low Level Laser Therapy on Orthodontic Tooth Movement: A Review Article  

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Full Text Available Increased duration of fixed orthodontic treatments leads to increased tooth root degeneration, gum inflammation and tooth caries. To decrease the time period of orthodontic treatment, it is essential to facilitate tooth movement or in other words increase the speed of bone remodeling. Use of low level laser therapy is a method for achieving this goal.

Soghra Yassaei

2013-01-01

208

Methods of Detecting Charcot-Marie Tooth Disease Type 2A.  

Science.gov (United States)

Methods are described for screening a subject for risk of Charcot-Marie-Tooth Disease Type 2A or for diagnosing Charcot-Marie-Tooth disease or a predisposition for developing Charcot-Marie-Tooth disease in a subject, by detecting the presence or absence o...

J. M. Vance, S. Zuchner, M. A. Vance

2004-01-01

209

Mandibular buccal bifurcation cyst: enucleation without extraction.  

Science.gov (United States)

The mandibular buccal bifurcation cyst (MBBC) is a cystic lesion, which occurs on the buccal surface of the permanent mandibular first molar in children around 6-8 years old. Treatment of the cyst has been controversial: extraction of the involved tooth and enucleation of the cyst, or only enucleation, without extraction. The aim of this article is to familiarize oral and maxillofacial surgeons with this entity and the appropriate treatment approach. The diagnostic features of MBBC are described and the treatment approach in five patients with a total of seven cysts is presented. Two cases were identified in identical twins. Enucleation of the cyst without extraction of the involved tooth is the treatment of choice when the available data and experience in treating MBBC are considered. PMID:14636611

Shohat, I; Buchner, A; Taicher, S

2003-12-01

210

Comparison of intermaxillary tooth size discrepancies among different malocclusion groups.  

Science.gov (United States)

The purpose of this study was to determine whether there is a prevalent tendency for intermaxillary tooth size discrepancies among different malocclusion groups. This study consisted of 60 subjects who served as the normal occlusion group and 300 patients divided into 5 malocclusion groups (ie, Class I with bimaxillary protrusion, Class II Division 1, Class II Division 2, Class III, and Class III surgery). Tooth size measurements were performed on the models of normal occlusion and pretreatment models of patients by the Three Dimension Measuring Machine. Moreover, tooth size ratios, analyzed as described by Bolton and the Student t test showed no sexual dimorphism for these ratios in each of 6 groups, so the sexes were combined for each group. Then these ratios were compared among different malocclusion groups. The results showed no significant difference between subcategories of malocclusion, so these groups were combined. There were now 120 cases in each of 3 categories: Class I, Class II, and Class III. A significant difference was found for all the ratios between the groups, the ratios showing that Class III > Class I > Class II. It demonstrated that intermaxillary tooth size discrepancy may be one of the important factors in the cause of malocclusions, especially in Class II and Class III malocclusions. Thus this study proved the fact that Bolton analysis should be taken into consideration during orthodontic diagnosis and therapy. PMID:10547514

Nie, Q; Lin, J

1999-11-01

211

Functional convergence in bat and toothed whale biosonars  

DEFF Research Database (Denmark)

Echolocating bats and toothed whales hunt and navigate by emission of sound pulses and analysis of returning echoes to form a self-generated auditory scene. Here, we demonstrate a striking functional convergence in the way these two groups of mammals independently evolved the capability to sense with sound in air and water.

Madsen, P T; Surlykke, Annemarie

2013-01-01

212

Surgical treatments of the impacted canine tooth in young dogs  

International Nuclear Information System (INIS)

Surgical treatments of the impacted canine tooth were carried out in 8 young dogs, and the results were successful in 12 out of 14 cases (85.7%). The treatments consisting of surgical correction by immediate tipping movement, fenestration of the gingiva, and removal of the impacted tooth, were applied to 14 cases radiographically showing the immature tooth root and no abnormalities in the tooth root or alveolar bone. Impacted teeth were seen in 8 regions of the maxilla and 6 regions of the mandible. Mesioversion was seen in almost all maxillary impacted teeth, while linguoversion or lingual mesioversion in all mandibular cases. Surgical correction was carried out by immediate tipping movement after removal of the retained deciduous canine with or without resection of the alveolar bone. Fixation of the moved teeth was done using a wedge made from the deciduous canine root, which was driven into the vacant alveolar cavity after moving. An additional fixation using a steel wire and/or self-curing resin was done, if necessary

213

Risk indicators for tooth loss in adult workers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Tooth loss continues to be a prevalent condition in Brazilian adults and elderly individuals. The aim of this cross-sectional study, conducted among workers in a wholesale grocery chain in the State of São Paulo, was to identify risk indicators for tooth loss in adults. The presence of caries and pe [...] riodontal status were examined in 387 adults aged 20-64 years, according to World Health Organization criteria. Two outcomes were analyzed: loss of one or more teeth, and loss of four or more teeth. Independent variables analyzed were demographic and socioeconomic factors, clinical conditions, use of dental services, and self-perceived oral health. Poisson regression models were used for multivariate statistical analysis. Participants were missing a mean of 5.38 teeth, and 76.9% (n = 297) had lost at least one tooth; the most frequently lost teeth were permanent molars. Older age and the presence of visible dental biofilm were associated significantly with the two tooth loss outcomes (p

Marília Jesus, Batista; Lílian Berta, Rihs; Maria da Luz Rosário de, Sousa.

2012-10-01

214

Risk indicators for tooth loss in adult workers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Tooth loss continues to be a prevalent condition in Brazilian adults and elderly individuals. The aim of this cross-sectional study, conducted among workers in a wholesale grocery chain in the State of São Paulo, was to identify risk indicators for tooth loss in adults. The presence of caries and pe [...] riodontal status were examined in 387 adults aged 20-64 years, according to World Health Organization criteria. Two outcomes were analyzed: loss of one or more teeth, and loss of four or more teeth. Independent variables analyzed were demographic and socioeconomic factors, clinical conditions, use of dental services, and self-perceived oral health. Poisson regression models were used for multivariate statistical analysis. Participants were missing a mean of 5.38 teeth, and 76.9% (n = 297) had lost at least one tooth; the most frequently lost teeth were permanent molars. Older age and the presence of visible dental biofilm were associated significantly with the two tooth loss outcomes (p

Marília Jesus, Batista; Lílian Berta, Rihs; Maria da Luz Rosário de, Sousa.

215

About Kids' Teeth: Baby Tooth Decay is Real  

Medline Plus

Full Text Available ... news – decay is mostly preventable . What Are Cavities? Causes of Decay Tooth decay begins when cavity-causing bacteria is passed to an infant. For ... and then put it in your baby’s mouth, cavity-causing bacteria is passed to the baby. Another ...

216

Protection and Reinforcement of Tooth Structures by Dental Coating Materials  

Directory of Open Access Journals (Sweden)

Full Text Available It has been proposed that a resin coating can serve as a means to protect dental structure after preparation of the tooth for indirect restorations, sealing the exposed dentin. The resin coating is applied on the cut surfaces immediately after tooth preparation and before making an impression by assembling a dentin bonding system and a flowable composite. Resin coatings minimize pulp irritation and improve the bond strength between a resin cement and tooth when bonding the restoration to tooth. Recently, thin-film coating dental materials based on all-in-one adhesive technology were introduced for resin coating of indirect restorations. The thin coating materials are applied in a single clinical step and create a barrier-like film layer on the prepared dentin. The thin coatings play an important role in protecting the dentin from physical, chemical, and biological irritation. In addition, these thin-film coating materials reportedly prevent marginal leakage beneath inlays or crown restorations. In light of the many benefits provided by such a protective layer, these all-in-one adhesive materials may therefore also have the potential to cover exposed root dentin surfaces and prevent caries formation. In this paper, recent progress of the dental coating materials and their clinical applications are reviewed.

Toru Nikaido

2012-10-01

217

Dose estimation of two victims in a severe radiation accident by using tooth enamel  

International Nuclear Information System (INIS)

Objective: To estimate the exposed dose levels of 2 two victims, who died one month after they were accidentally irradiated by Cobalt-60. Methods: Three teeth were extracted from 2 victims. The signal intensities of separated enamel samples were measured with ESR spectrometer. The accumulated exposed doses were reconstructed according to a calibration curve established using Cobalt-60 ?-rays. Results: A calibration curve between signal intensity and exposed dose was established. The estimated doses of 3 teeth were 26.1 ? 29.4 Gy, for victim A, 14.9 ? 18.3 Gy and 15.2 ? 18.5 Gy for victim B. The doses are close to the result of the other Laboratory. Conclusion: The application of ESR dosimetry in human tooth enamel could provide important information for a dose estimation of victims exposed to heavy doses of radiation. (authors)

218

ESR Dosimetry Below 1 Gy, in X-Ray Irradiated Tooth Enamel  

International Nuclear Information System (INIS)

Tooth enamel, extracted from molars, was irradiated with 66keV X-rays, with doses up to 1Gy.The preparation of the powder samples is described, as well as the protocol for the acquisition and processing of the spectra.The radiation induced paramagnetism is measured, at room temperature, by ESR Spectroscopy.The ESR spectra is well described considering two paramagnetic species, with magnetic moments (in units of Bohr magnetons) g=2,0041, and g1=2,0018, g2=1,9972.The ESR data (peak-to-peak amplitude per mg, hpp/mg, vs dose D), for doses 0Gy2 =0,996) with the linear expression: [hpp/mg] = -0,2( 0,4)+14,9(0,5). D [Gy].The result supports the growing confidence in the use of this material, and method, in Retrospective Dosimetry

219

Effect of bleaching gel in Ca, P and Zn content in tooth enamel evaluated by ?-EDXRF  

Science.gov (United States)

The purpose of this in vitro study is to assess whether the elemental content of P, Ca and Zn in tooth enamel is altered when bleaching the teeth with bleaching gel. In order to perform this evaluation, sound vestibular surfaces of six anterior healthy teeth, extracted for periodontal or orthodontic reasons were used. Cuts were made in order to obtain 8 × 2 mm samples. Samples were then treated with the bleaching product (Opalescence PF 10%) accordingly to manufacturer instructions and stocked in artificial saliva between each application. The elemental content of each sample, before and after treatment was obtained by a portable micro Energy Dispersive X-ray Spectrometry (?-EDXRF), making use of a polycapillary optic to obtain a focal spot of 100 ?m for Fe-K?. Quantitative calculations were obtained by WinAXIL compare mode method, using four standard reference materials. The obtained results show that no significant statistic differences were observed for the studied elements.

Godinho, J.; Silveira, J.; Mata, A.; Carvalho, M. L.; Pessanha, S.

2014-10-01

220

Single Anterior Tooth Replacement by a Cast Lingual Loop Connector - A Conservative Approach  

Science.gov (United States)

One of the most challenging and complex treatment modality is replacement of single anterior tooth. This can be overcome by different treatment options such as implant-supported restorations as well as conventional porcelain-fused-to-metal and resin-bonded fixed partial dentures. Drifting of teeth into the edentulous area may reduce the available pontic space; whereas a diastema existing before an extraction may result in excessive mesiodistal dimension to the pontic space. Loop connector fixed partial denture (FPD) may be the simplest and best solution to maintain the diastema and provide optimum restoration of aesthetics. This article describes the procedure for the fabrication of a loop connector FPD to restore an excessively wide anterior edentulous space in a patient with existing spacing between the maxillary anterior teeth. PMID:25386535

Dandekeri, Savita

2014-01-01

 
 
 
 
221

Dental patterning in the earliest sharks: Implications for tooth evolution.  

Science.gov (United States)

Doliodus problematicus is the oldest known fossil shark-like fish with an almost intact dentition (Emsian, Lower Devonian, c. 397Ma). We provide a detailed description of the teeth and dentition in D. problematicus, based on tomographic analysis of NBMG 10127 (New Brunswick Museum, Canada). Comparisons with modern shark dentitions suggest that Doliodus was a ram-feeding predator with a dentition adapted to seizing and disabling prey. Doliodus provides several clues about the early evolution of the "shark-like" dentition in chondrichthyans and also raises new questions about the evolution of oral teeth in jawed vertebrates. As in modern sharks, teeth in Doliodus were replaced in a linguo-labial sequence within tooth families at fixed positions along the jaws (12-14 tooth families per jaw quadrant in NBMG 10127). Doliodus teeth were replaced much more slowly than in modern sharks. Nevertheless, its tooth formation was apparently as highly organized as in modern elasmobranchs, in which future tooth positions are indicated by synchronized expression of shh at fixed loci within the dental epithelium. Comparable dental arrays are absent in osteichthyans, placoderms, and many "acanthodians"; a "shark-like" dentition, therefore, may be a synapomorphy of chondrichthyans and gnathostomes such as Ptomacanthus. The upper anterior teeth in Doliodus were not attached to the palatoquadrates, but were instead supported by the ethmoid region of the prechordal basicranium, as in some other Paleozoic taxa (e.g., Triodus, Ptomacanthus). This suggests that the chondrichthyan dental lamina was originally associated with prechordal basicranial cartilage as well as jaw cartilage, and that the modern elasmobranch condition (in which the oral dentition is confined to the jaws) is phylogenetically advanced. Thus, oral tooth development in modern elasmobranchs does not provide a complete developmental model for chondrichthyans or gnathostomes. PMID:24347366

Maisey, John G; Turner, Susan; Naylor, Gavin J P; Miller, Randall F

2014-05-01

222

Tooth engineering: searching for dental mesenchymal cells sources.  

Directory of Open Access Journals (Sweden)

Full Text Available The implantation of cultured re-associations between embryonic dental mesenchymal cells and epithelial cells from mouse molars at ED14 allowed making full teeth with crown, root, periodontal ligament fibers and bone. Although representing valuable tools to set up methodologies embryonic cells are not easily available. This work thus aimed to replace the embryonic cells by dental mesenchymal cell lines or cultured expanded embryonic cells, and to test their ability to mediate tooth development in vitro when re-associated with a competent dental epithelium. Histology, immunostaining and RT-PCR allowed getting complementary sets of results. Two different immortalized cell lines from ED18 dental mesenchyme failed in mediating tooth formation. The potentialities of embryonic dental mesenchymal cells decreased from ED14 to ED16 and were lost at ED18. This is likely related to a change in the mesenchymal cell phenotype and/or populations during development. Attempts to cultivate ED14 or ED16 embryonic dental mesenchymal cells prior to re-association led to the loss of their ability to support tooth development. This was accompanied by a down-regulation of Fgf3 transcription. Supplementation of the culture medium with FGF2 allowed restoring Fgf3 expression, but not the ability of mesenchymal cells to engage in tooth formation. Altogether, these observations suggest that a competent cell population exists in the dental mesenchyme at ED14, progressively decreases during development, and cannot as such be maintained in vitro. This study evidenced the need for specific conditions to maintain the ability of dental mesenchymal cells to initiate whole tooth formation, when re-associated with an odontogenic epithelium. Efforts to improve the culture conditions will have to be combined with attempts to characterize the competent cells within the dental mesenchyme.

HervéLesot

2011-03-01

223

In Vitro Color Change of Three Dental Veneering Resins in Tea, Coffee and Tamarind Extracts  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To study the in vitro color changes of three dental resin veneering materials when immersed in tea, coffee and tamarind extracts.Materials and Methods: The color changes of heat polymerized tooth colored acrylic resin (Stellondetrey, B, F14, DPI Dental products of India Ltd, Mumbai, auto polymerized tooth colored acrylic resin (DPI, B, QV5, DPI Dental products of India Ltd, Mumbai andlight polymerized resin composite (Herculite XRV, Enamel A2, part no. 22860, lot no. 910437, Kerr Corporation, West Collins Avenue, Orange, CA, USA when immersed in water extracts of tea (Tata Tea Ltd. Bangalore, India, coffee (Tata Coffee Ltd. Coorg, Indiaand tamarind were evaluated using computer vision systems. The color images were recorded in R (red, G (green and B (blue form and converted into H (hue, S (saturationand V (value.Results: Significant color change occurred for auto polymerized tooth colored acrylic resin in tamarind extract, for heat polymerized tooth colored acrylic resin in tea extract andfor light polymerized resin composite in coffee extract. Auto polymerized tooth colored acrylic resin samples showed an overall higher color change. However, for all the material samples coffee extract produced more color change.Conclusion: These results suggest that the color stability of the resins is influenced by the presence of secondary metabolites such as tartaric acid, tannins, caffeine, saponins and phenols in tamarind, tea and coffee extracts.

S. Muttagi

2011-09-01

224

A design of speed reducer with trapezoidal tooth profile for robot manipulator  

Energy Technology Data Exchange (ETDEWEB)

Robots are increasingly performing human work as manufacturing is automated. Accordingly, the use of precision speed reducers has become essential for achieving precise control of the robot arm position. Curved tooth profiles, such as cycloid or involute tooth profiles, are generally used in precision speed reducers. Speed reducers with cycloid tooth profiles, which enable high precision control, are widely used to manipulate robot systems. This study proposes a speed reducer that has a trapezoidal tooth profile with straight lines. In this work, we mechanically analyzed trapezoidal tooth profiles, and then measured performance was by various tests using a prototype manufactured specifically for this study.

Nam, Won Ki; Oh, Se Hoon [Chung-Ang University, Seoul (Korea, Republic of)

2011-01-15

225

Cell fate determination during tooth development and regeneration.  

Science.gov (United States)

Teeth arise from sequential and reciprocal interactions between the oral epithelium and the underlying cranial neural crest-derived mesenchyme. Their formation involves a precisely orchestrated series of molecular and morphogenetic events, and gives us the opportunity to discover and understand the nature of the signals that direct cell fates and patterning. For that reason, it is important to elucidate how signaling factors work together in a defined number of cells to generate the diverse and precise patterned structures of the mature functional teeth. Over the last decade, substantial research efforts have been directed toward elucidating the molecular mechanisms that control cell fate decisions during tooth development. These efforts have contributed toward the increased knowledge on dental stem cells, and observation of the molecular similarities that exist between tooth development and regeneration. PMID:19750524

Mitsiadis, Thimios A; Graf, Daniel

2009-09-01

226

Graphene-based wireless bacteria detection on tooth enamel  

Science.gov (United States)

Direct interfacing of nanosensors onto biomaterials could impact health quality monitoring and adaptive threat detection. Graphene is capable of highly sensitive analyte detection due to its nanoscale nature. Here we show that graphene can be printed onto water-soluble silk. This in turn permits intimate biotransfer of graphene nanosensors onto biomaterials, including tooth enamel. The result is a fully biointerfaced sensing platform, which can be tuned to detect target analytes. For example, via self-assembly of antimicrobial peptides onto graphene, we show bioselective detection of bacteria at single-cell levels. Incorporation of a resonant coil eliminates the need for onboard power and external connections. Combining these elements yields two-tiered interfacing of peptide-graphene nanosensors with biomaterials. In particular, we demonstrate integration onto a tooth for remote monitoring of respiration and bacteria detection in saliva. Overall, this strategy of interfacing graphene nanosensors with biomaterials represents a versatile approach for ubiquitous detection of biochemical targets.

Mannoor, Manu S.; Tao, Hu; Clayton, Jefferson D.; Sengupta, Amartya; Kaplan, David L.; Naik, Rajesh R.; Verma, Naveen; Omenetto, Fiorenzo G.; McAlpine, Michael C.

2012-03-01

227

Selective formation of metastable ferrihydrite in the chiton tooth.  

Science.gov (United States)

Metastable precursors are thought to play a major role in the ability of organisms to create mineralized tissues. Of particular interest are the hard and abrasion-resistant teeth formed by chitons, a class of rock-grazing mollusks. The formation of chiton teeth relies on the precipitation of metastable ferrihydrite (Fh) in an organic scaffold as a precursor to magnetite. In?vitro synthesis of Fh under physiological conditions has been challenging. Using a combination of X-ray absorption and electron paramagnetic resonance spectroscopy, we show that, prior to Fh formation in the chiton tooth, iron ions are complexed by the organic matrix. In?vitro experiments demonstrate that such complexes facilitate the formation of Fh under physiological conditions. These results indicate that acidic molecules may be integral to controlling Fh formation in the chiton tooth. This biological approach to polymorph selection is not limited to specialized proteins and can be expropriated using simple chemistry. PMID:25196134

Gordon, Lyle M; Román, Jessica K; Everly, R Michael; Cohen, Michael J; Wilker, Jonathan J; Joester, Derk

2014-10-20

228

Regulated fracture in tooth enamel: a nanotechnological strategy from nature.  

Science.gov (United States)

Tooth enamel is a very brittle material; however it has the ability to sustain cracks without suffering catastrophic failure throughout the lifetime of mechanical function. We propose that the nanostructure of enamel can play a significant role in defining its unique mechanical properties. Accordingly we analyzed the nanostructure and chemical composition of a group of teeth, and correlated it with the crack resistance of the same teeth. Here we show how the dimensions of apatite nanocrystals in enamel can affect its resistance to crack propagation. We conclude that the aspect ratio of apatite nanocrystals in enamel determines its resistance to crack propagation. According to this finding, we proposed a new model based on the Hall-Petch theory that accurately predicts crack propagation in enamel. Our new biomechanical model of enamel is the first model that can successfully explain the observed variations in the behavior of crack propagation of tooth enamel among different humans. PMID:24813507

Ghadimi, Elnaz; Eimar, Hazem; Song, Jun; Marelli, Benedetto; Ciobanu, Ovidiu; Abdallah, Mohamed-Nur; Stähli, Christoph; Nazhat, Showan N; Vali, Hojatollah; Tamimi, Faleh

2014-07-18

229

Selective saturation method for EPR dosimetry with tooth enamel.  

Science.gov (United States)

The method of selective saturation proposed is based on the difference in the microwave (mw) power dependence of the background and radiation induced EPR components of the tooth enamel spectrum. The subtraction of the EPR spectrum recorded at low mw power from that recorded at higher mw power provides a considerable reduction of the background component in the spectrum. The resolution of the EPR spectrum could be improved 10-fold, however simultaneously the signal-to-noise ratio was found to be reduced twice. A detailed comparative study of reference samples with known absorbed doses was performed to demonstrate the advantage of the method. The application of the selective saturation method for EPR dosimetry with tooth enamel reduced the lower limit of EPR dosimetry to about 100 mGy. PMID:8935967

Ignatiev, E A; Romanyukha, A A; Koshta, A A; Wieser, A

1996-03-01

230

Preferred treatment methods for primary tooth vital pulpotomies. A survey.  

Science.gov (United States)

This investigation evaluated preferred treatment methods for primary tooth vital pulpotomies. One hundred and thirty surveys were sent to a randomly selected sample of board-certified pediatric dentists practicing in the United States. Ninety-two questionnaires were returned, for a 71% response rate. This yielded a sample group of 92 board-certified pediatric dentists. The most commonly used medicament was formocresol. Seventy-three percent using formocresol said they were not concerned about adverse side effects of formocresol and formaldehyde. Sixty-one percent of respondents used formocresol for primary tooth vital pulpotomies. Twenty-eight percent of respondents used undiluted, and 33% used diluted. The results of this survey suggest that the majority of dentists who used formocresol were not concerned with any adverse effects. PMID:18450190

Yoon, Richard K; Chussid, Steven; Davis, Martin J; Bruckman, Karl C

2008-03-01

231

Characteristics of Rotary Electromagnet with Large Tooth-pitch Angle  

Directory of Open Access Journals (Sweden)

Full Text Available Since the conventional electro-mechanical converter of 2D valve had problems of step lose due to its small tooth-pitch angle, a novel rotary electromagnet with large tooth-pitch angle and coreless rotor structure was proposed. Combined with the approaches of magnetic circuit analysis, finite element simulation and experimental study, the static and dynamic characteristics of electromagnet including torque-angle characteristics, frequency response and step response were studied. The experimental results are in a close agreement with the simulated results. The electromagnet has sinusoidal torque-angle characteristics and good dynamic response. The maximum static torque is approximately 0.083N.M, and its frequency width is about 125Hz/-3dB, 130Hz/-90°, respectively, and the rise time is about 5.5 ms. It is appropriate to be used as the electro-mechanical converter of 2D proportional valve.

Ruan Jian

2012-10-01

232

DENTAL IMPLANTS: AS AN ALTERNATIVE FOR TOOTH REPLACEMENT  

Directory of Open Access Journals (Sweden)

Full Text Available A dental implant is an artificial tooth that replaces a tooth that has been taken out. Implants are natural-looking, can provide support for dentures and do not affect the teeth bordering them. They are as stable as your real teeth and protect you from the loss of jawbone, which occurs when you lose teeth. Endosseous dental implants have revolutionized the fields of implants and periodontics. During the last decade, a great deal of information has been generated concerning the effectiveness and predictability of endosseous implants. Implant placement is a viable option in the treatment of partial and full edentulism and has become an integral facet of periodontal therapy. The available implants are remarkably successful. This review discusses the different aspects of dental implant including its advantages over the contemporary removable implants, its procedure in detail and the financial outlook of the same. The review also has a small consideration on minidental implant.

Banerjee Nandini

2013-08-01

233

Structural and radiographic evaluation of four cases of tooth fusion.  

Science.gov (United States)

Four cases of tooth fusion are presented. Three of the patients were female and one male. Radiographic examination revealed union of calcified tissues with discrete root canals and a common pulp chamber in Case 3 and the converse in Case 4. The finding of fused mandibular incisors and canines in both the deciduous and permanent dentitions is described in Case 1, while in two others unilateral fused tooth masses are described which are not repeated in the permanent dentition. The dentist should be aware of the possibility of finding fused teeth on routine dental inspection and once diagnosed the patient should be informed of the potential hazards as regards plaque accumulation and varied root canal morphology. PMID:2393359

O'Reilly, P M

1990-06-01

234

Comparative evaluation of soft tissue characteristics around implant and tooth  

Directory of Open Access Journals (Sweden)

Full Text Available "nBackground and Aim: Soft tissue condition around dental implant is an essential part for long term healthy and esthetic outcome. The aim of this study was to compare soft tissue dimensions between implant supported single  tooth replacement and the contra-lateral natural tooth. "nMaterials and Methods: This retrospective study was performed on dentate patients treated with anterior single  tooth implant at least 1 year ago. Of twenty eight, fourteen patients had been treated with one stasge method and others with two stage method. Biologic width (BW, papilla index (PI, and mucosal thickness (MT were evaluated around implants and contra-lateral teeth clinically and compared with each other. The Wilcoxon test, Mann-Whitney test, and Student pair t-test were used to assess the differences between one stasge and two stage implants, and implant and tooth groups. "nResults: The mean BW around one stasge implants, two stage implants, and contra-lateral teeth were 1.42±0.48 mm, 1.67±0.48 mm, and 1.47±0.60 mm, respectively. The mean PI adjacent to one stasge implants, Two stage implants, and contra-lateral teeth were 2.50±0.52, 2.53±0.55, and 2.72±0.47, correspondingly. The mean MT around one stasge implants, two stage implants, and contra-lateral teeth were 3.10±0.48, 3.09±0.75, and 2.57±0.88, respectively. There was no statistically significant difference among one stasge implants, two stage implants, and contra-lateral teeth with regard to measured variables. "nConclusion: Based on the results of this investigation, in standard condition, it seems that there is no noticeable difference in indicators of; biologic width, papilla index, and mucosal thickness around one stasge implants, two stage implants, and contra-lateral teeth.

Paknejad M.

2008-12-01

235

Vestibular impairment in patients with Charcot-Marie-Tooth disease  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OBJECTIVE: This case-control study aimed to determine whether the imbalance in Charcot-Marie-tooth (CMT) disease is caused only by reduced proprioceptive input or whether the involvement of the vestibular nerve is an additional factor. METHODS: Fifteen patients with CMT disease (aged 48 ± 17 years; 8 women) underwent cervical vestibular-evoked myogenic potentials, which reflect otolith-spinal reflex function, and quantitative horizontal search-coil head-impulse testing, which assesses the h...

Poretti, A.; Palla, A.; Tarnutzer, A. A.; Petersen, J. A.; Weber, K. P.; Straumann, D.; Jung, H. H.

2013-01-01

236

An Invitro Evaluation of Coronal Microleakage in Strengthening of Weakend Teeth with Different Tooth-Coloured Material with  

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Full Text Available Introduction: The purpose of this in vitro study was to investigate coronal microlenkage in anterior weakend teeth after root canal therapy, reinforced with different tooth-coloured material and FRC post.Methods and Materials: A total 48 extracted intact central incisor were randomly divided into four experimental groups (n=12. All specimens were endodontically treated using lateral condensation and crowns were totally removed from 2mm of CEJ and were over flared to simulate weakened teeth . Control group (group I was restored only with gutta percha .In other groups root canal walls were prepared (etching, washing and gentle drying, bonding and the surface of the posts were cleaned with alcohol and after that covered with bonding agent and then light polymerized for 40 seconds. Finally post cementation was done durig reinforcing of weakened root canal walls with packable composite in group II, self-cure composite in group III and dual cure composite in group IV. All specimens were thermocycled for 500 cycles between 5ºc and 55ºc0 with a dowel time of 20 seconds before immersion in dye. Then all specimens were sealed with sticky wax and coated with two layer of nail polish & then they were placed in 0.5% fuchsine for 24 hours at room temperature and were sectioned longitudinally from the center of post with tooth cutter. Dye penetration in both sections of each tooth were evaluated using a stereomicroscope equipped with digital camera at original magnification of 32× and microleakage recorded in m. One-way analysis of variances (ANOVA and least square difference were used for statistical analysis.Result: The control group showed the maximum microleakage and the minimum was related to the third group .There was a significant difference among the average microleakage of all groups.Conclusion: Combination of FRC post and tooth-coloured materials did reinforce structurally compromised root and decreased microleakage and also the microleakage of root/bonding material is more than post/tooth-colored material. Microleakge in selfcure Group because of its polymerization was the least.

F - Shirani

2006-01-01

237

Associação na mesma família das doenças de Charcot-Marie-Tooth e de Friedreich Association of Charcot-Marie-Tooth and Friedreich diseases in a family  

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Full Text Available Quatro irmãos com moléstias de Charcot-Marie-Tooth são estudados do ponto de vista clínico e genético. São ressaltadas, mediante análise da sintomatologia, as formas de transição no grande grupo de moléstias heredodegenerativas, sendo atribuída particular ênfase às formas entre a moléstia de Charcot-Marie-Tooth e a de Friedreich. Nos casos apresentados havia sinais clínicos da amiotrofia de Charcot-Marie-Tooth e da degeneração espinocerebelar de Friedreich. No estudo genético foram observadas aberrações cromossômicas, fenômeno inédito na moléstia de Charcot-Marie-Tooth.Four brothers with Charcot-Marie-Tooth disease are studied clinically and genetically. By comparing the symptomatology, the mixed clinical forms within the great group of heredodegenerative diseases are enfazised, with special attention to the intermediate forms between Charcot-MarieTooth and Friedreich diseases. In the present cases there were signs of Charcot-Marie-Tooth's peroneal muscular atrophy and Friedreich's spinocerebelar degeneration. By the genetic study a cromosomal breakage, an unusual phenomenon in Charcot-Marie-Tooth disease, was observed.

Charles Peter Tilbery

1972-06-01

238

Associação na mesma família das doenças de Charcot-Marie-Tooth e de Friedreich / Association of Charcot-Marie-Tooth and Friedreich diseases in a family  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Quatro irmãos com moléstias de Charcot-Marie-Tooth são estudados do ponto de vista clínico e genético. São ressaltadas, mediante análise da sintomatologia, as formas de transição no grande grupo de moléstias heredodegenerativas, sendo atribuída particular ênfase às formas entre a moléstia de Charcot [...] -Marie-Tooth e a de Friedreich. Nos casos apresentados havia sinais clínicos da amiotrofia de Charcot-Marie-Tooth e da degeneração espinocerebelar de Friedreich. No estudo genético foram observadas aberrações cromossômicas, fenômeno inédito na moléstia de Charcot-Marie-Tooth. Abstract in english Four brothers with Charcot-Marie-Tooth disease are studied clinically and genetically. By comparing the symptomatology, the mixed clinical forms within the great group of heredodegenerative diseases are enfazised, with special attention to the intermediate forms between Charcot-MarieTooth and Friedr [...] eich diseases. In the present cases there were signs of Charcot-Marie-Tooth's peroneal muscular atrophy and Friedreich's spinocerebelar degeneration. By the genetic study a cromosomal breakage, an unusual phenomenon in Charcot-Marie-Tooth disease, was observed.

Charles Peter, Tilbery; Décio Cassiani, Altimari; Luiz G., Gagliardi-Ferreira; José L., Alonso Nieto.

239

Advanced digital photoelastic investigations on the tooth-bone interface.  

Science.gov (United States)

The purpose of this study was to investigate the behavior of the tooth-bone interface on the nature of stress distribution in the tooth and its supporting alveolar bone for various occlusal loads using an advanced digital photoelastic technique. A digital image processing system coupled with a circular polariscope was used for the stress analysis. The phase shift technique and a phase unwrapping algorithm was utilized for fringe processing. This aids in obtaining qualitative and quantitative information on the nature of stress distribution within the dento-osseous structures. The experiments revealed bending stresses within dento-osseous structures. However, the compressive stress magnitude was larger than the tensile stress. Zero stress regions were also identified within the dento-osseous structures. The results suggest that the geometry of the dento-osseous structures and the structural gradients at the tooth-bone interface play a significant role in the distribution of stresses without stress concentrations. Further, the application of an advanced image-processing system with the circular polariscope showed notable advantages and could be applied in other biomechanical investigations. PMID:11375733

Asundi, A; Kishen, A

2001-04-01

240

Developmental genetic mechanisms of evolutionary tooth loss in cypriniform fishes.  

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The fossil record indicates that cypriniform fishes, a group including the zebrafish, lost oral teeth over 50 million years ago. Despite subsequent diversification of feeding modes, no cypriniform has regained oral teeth, suggesting the zebrafish as a model for studying the developmental genetic basis of evolutionary constraint. To investigate the mechanism of cypriniform tooth loss, we compared the oral expression of seven genes whose mammalian orthologs are involved in tooth initiation in the zebrafish and the Mexican tetra, Astyanax mexicanus, a related species retaining oral teeth. The most significant difference we found was an absence in zebrafish oral epithelium of expression of dlx2a and dlx2b, transcription factors that are expressed in early Astyanax odontogenic epithelium. Analysis of orthologous genes in the Japanese medaka (Oryzias latipes) and a catfish (Synodontis multipunctatus) suggests that expression was lost in cypriniforms, rather than gained in Astyanax. Treatment of Astyanax with an inhibitor of Fibroblast growth factor (Fgf) signaling produced a partial phenocopy of the zebrafish oral region, in that oral teeth, and expression of dlx2a and dlx2b, were lost, whereas shh and pitx2, genes whose expression is present in zebrafish oral epithelium, were unaffected. We hypothesize that a loss of Fgf signaling to oral epithelium was associated with cypriniform tooth loss. PMID:16831836

Stock, David W; Jackman, William R; Trapani, Josh

2006-08-01

 
 
 
 
241

[Case of reimplanted tooth with long-lasting clinical effect].  

Science.gov (United States)

The author describes a case of reimplantation of 44 of a 35-year-old woman, 19 years ago. Later, 10 years after the reimplantation apical osteotomy, according to indications, was performed to the same tooth. The X-ray, performed in 1985, shows that resorptive processes around the tooth and root has not advances as yet. It started after the root treatment on the adjecent 46 in 1985. The author thinks that the mass failure of teeth reimplantation (short-term therapeutic effect of 5-6 years and not with all reimplantations) reduces the interest of the researchers in it without any grounds. The case described shows that, very likely, under certain conditions and certain operation technique, unconsciously blended in the case described, very good therapeutic effect could be relied on via the reimplantation. It is presumed that the initiation of resorption has been provoked by the devitalization of an adjacent tooth, possibly due to disturbed trophicity in the region around it. It has been concluded that a great many problems, still unknown, of teeth reimplantation wait their proper solution. PMID:3274198

Nedkov, R

1988-01-01

242

New population of odontoblasts responsible for tooth root formation.  

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Root formation is initiated with the extension of Hertwig's epithelial root sheath (HERS) after crown morphogenesis. To date, little is known about the molecular and cellular mechanisms controlling root formation. Recently we found rootless molars are formed in the dental mesenchyme-specific ?-catenin conditional knockout mice. The striking root phenotypes of these mutant mice result from the disrupted differentiation of differentiating odontoblasts, caused by ablation of ?-catenin during initiation of root formation. Here we show the cellular and molecular characteristics of differentiating odontoblasts using histochemistry and immunohistochemistry. These cells were not found in crown formation, but appeared only in the apical end of developing tooth, thus we have named these cells "apical odontoblasts" (AOds). AOds appeared immediately after HERS formation and were always present on the apical side of developing roots until root formation was complete. These findings indicate that AOds are closely associated with the transition from crown to root and with root elongation. In AOds, several transcription factors, including Nfic, Creb3l1, and Osx, as well as ?-catenin and alkaline phosphatase were expressed but Phex and Dspp were not expressed. Taken together, our results indicate that AOds are the principal cells responsible for tooth root formation. These findings may contribute to the further understanding of the mechanisms underlying tooth root formation and root regeneration. PMID:23603379

Bae, Cheol-Hyeon; Kim, Tak-Heun; Chu, Jung-Yob; Cho, Eui-Sic

2013-01-01

243

Neural crest stem cell property of apical pulp cells derived from human developing tooth.  

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Recent reports have described that NCSCs (neural crest-derived stem cells) are not only present in the embryonic neural crest but also in the adult tissues. Dental pulp is one of mesenchymal soft tissues origin from cranial neural crest cells, and thought to be a source of adult stem cells. Here, we investigated the existence of NCSC-like cells in apical pulp of human developing tooth. Human impacted third molars with immature apex freshly extracted were obtained. The cells derived from the apical pulp tissue not framed by dentin or the coronal pulp tissues were cultured by primary explant culture. APDCs (apical pulp-derived cells) and CPCs (coronal pulp cells) formed spheres under neurosphere culture condition. The number of spheres from APDCs was larger than that from CPCs. The sphere-forming cells derived from APDCs had self-renewal capacity, and expressed neural crest-associated markers (p75, Snail and Slug) and NSC (neural stem cell) markers (Nestin and Musashi1). The expression pattern of mesenchymal stem cell markers, CD105 and CD166, on the surface of sphere-forming cells derived APDCs was different from that of APDCs. These sphere-forming cells could differentiate into multiple mesenchymal lineages (osteoblasts, adipocytes, chondrocytes and smooth muscle cells) and neural lineage (neurons) in vitro, and generated ectopic bone tissues on the border of HA (hydroxyapatite) scaffold in vivo. The results of this study suggest that APDCs contain cells with characteristics of NCSCs reported previously in mice. Humans developing tooth with immature apex is an effective source of cells for neural crest lineage tissue regeneration. PMID:22731688

Abe, Shigehiro; Hamada, Keiichi; Miura, Masahiko; Yamaguchi, Satoshi

2012-10-01

244

Fracture toughness of zirconia ceramic crowns made by feather-edge tooth preparation design  

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Full Text Available Background/Aim. Fracture toughness determines functional crown strenght and prevents damages on ceramics during mastication. There is a lack of relevant literature data about fracture toughness of crowns made by feather-edge preparation. Mechanical testing of ceramic samples is supposed to show if feather-edge tooth preparation is a successful method for making ceramic crowns without any risk of reduction of their mechanical properties. This research was done to establish effects of feather-edge tooth preparation on fracture toughness of single zirconia ceramic crowns. Methods. The research was performed as an experimental study. Sixty (60 ceramic crowns were made on non-carious extracted human premolars. Thirty (30 crowns were made on the basis of feather-edge preparation (experimental group I. The group II included 30 crowns made on 1 mm rounded shoulder. Crowns fabrication was executed on a copy mill production system “Zirkonzahn” (Zirkonzahn GMBH, Gais, Germany. The spherical compression test was used to determine fracture toughness, using 6 mm diameter ceramic ball. Fracture load for damaging ceramic crown was recorded on a universal testing machine - Zwick, type 1464, with the speed of 0.05 mm/min. Results. The results of this research introduced significant differences between fracture toughness of ceramic samples in every examined group. However, fracture toughness of crowns from both group was above 2 000 N, what was double beyond a recommended value. The mean value of fracture toughness in the feather-edge group was 2 090 N, and in shoulder group it was 2 214 N. Conclusion. This research showed a high fracture toughness of zirconia crowns made on feather-edge preparation. The examined crowns showed a fracture resistance at a sufficient distance in relation to the minimum values of functional loads. Further research of functional loads of these crown is necessary, as well as research of marginal adaptation of cemented crowns and gingival inflammatory response.

Mirkovi? Nemanja

2012-01-01

245

Phosphoproteomes of Strongylocentrotus purpuratus shell and tooth matrix: identification of a major acidic sea urchin tooth phosphoprotein, phosphodontin  

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Full Text Available Abstract Background Sea urchin is a major model organism for developmental biology and biomineralization research. However, identification of proteins involved in larval skeleton formation and mineralization processes in the embryo and adult, and the molecular characterization of such proteins, has just gained momentum with the sequencing of the Strongylocentrotus purpuratus genome and the introduction of high-throughput proteomics into the field. Results The present report contains the determination of test (shell and tooth organic matrix phosphoproteomes. Altogether 34 phosphoproteins were identified in the biomineral organic matrices. Most phosphoproteins were specific for one compartment, only two were identified in both matrices. The sea urchin phosphoproteomes contained several obvious orthologs of mammalian proteins, such as a Src family tyrosine kinase, protein kinase C-delta 1, Dickkopf-1 and other signal transduction components, or nucleobindin. In most cases phosphorylation sites were conserved between sea urchin and mammalian proteins. However, the majority of phosphoproteins had no mammalian counterpart. The most interesting of the sea urchin-specific phosphoproteins, from the perspective of biomineralization research, was an abundant highly phosphorylated and very acidic tooth matrix protein composed of 35 very similar short sequence repeats, a predicted N-terminal secretion signal sequence, and an Asp-rich C-terminal motif, contained in [Glean3:18919]. Conclusions The 64 phosphorylation sites determined represent the most comprehensive list of experimentally identified sea urchin protein phosphorylation sites at present and are an important addition to the recently analyzed Strongylocentrotus purpuratus shell and tooth proteomes. The identified phosphoproteins included a major, highly phosphorylated protein, [Glean3:18919], for which we suggest the name phosphodontin. Although not sequence-related to such highly phosphorylated acidic mammalian dental phosphoproteins as phosphoryn or dentin matrix protein-1, phosphodontin may perform similar functions in the sea urchin tooth. More than half of the detected proteins were not previously identified at the protein level, thus confirming the existence of proteins only known as genomic sequences previously.

Mann Matthias

2010-02-01

246

Rolling-Tooth Core Breakoff and Retention Mechanism  

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Sampling cores requires the controlled breakoff of the core at a known location with respect to the drill end. An additional problem is designing a mechanism that can be implemented at a small scale that is robust and versatile enough to be used for a variety of core samples. This design consists of a set of tubes (a drill tube and an inner tube) and a rolling element (rolling tooth). An additional tube can be used as a sample tube. The drill tube and the inner tube have longitudinal holes with the axes offset from the axis of each tube. The two eccentricities are equal. The inner tube fits inside the drill tube, and the sample tube fits inside the inner tube. While drilling, the two tubes are positioned relative to each other such that the sample tube is aligned with the drill tube axis and core. The drill tube includes teeth and flutes for cuttings removal. The inner tube includes, at the base, the rolling element implemented as a wheel on a shaft in an eccentric slot. An additional slot in the inner tube and a pin in the drill tube limit the relative motion of the two tubes. While drilling, the drill assembly rotates relative to the core and forces the rolling tooth to stay hidden in the slot along the inner tube wall. When the drilling depth has been reached, the drill bit assembly is rotated in the opposite direction, and the rolling tooth is engaged and penetrates into the core. Depending on the strength of the created core, the rolling tooth can score, lock the inner tube relative to the core, start the eccentric motion of the inner tube, and break the core. The tooth and the relative position of the two tubes can act as a core catcher or core-retention mechanism as well. The design was made to fit the core and hole parameters produced by an existing bit; the parts were fabricated and a series of demonstration tests were performed. This invention is potentially applicable to sample return and in situ missions to planets such as Mars and Venus, to moons such as Titan and Europa, and to comets. It is also applicable to terrestrial applications like forensic sampling and geological sampling in the field.

Badescu, Mircea; Bickler, Donald B.; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Hudson, Nicolas H.

2011-01-01

247

Nanofibers implant functionalized by neural growth factor as a strategy to innervate a bioengineered tooth.  

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Current strategies for jaw reconstruction require multiple procedures, to repair the bone defect, to offer sufficient support, and to place the tooth implant. The entire procedure can be painful and time-consuming, and the desired functional repair can be achieved only when both steps are successful. The ability to engineer combined tooth and bone constructs, which would grow in a coordinated fashion with the surrounding tissues, could potentially improve the clinical outcomes and also reduce patient suffering. A unique nanofibrous and active implant for bone-tooth unit regeneration and also the innervation of this bioengineered tooth are demonstrated. A nanofibrous polycaprolactone membrane is functionalized with neural growth factor, along with dental germ, and tooth innervation follows. Such innervation allows complete functionality and tissue homeostasis of the tooth, such as dentinal sensitivity, odontoblast function, masticatory forces, and blood flow. PMID:24124118

Eap, Sandy; Bécavin, Thibault; Keller, Laetitia; Kökten, Tunay; Fioretti, Florence; Weickert, Jean-Luc; Deveaux, Etienne; Benkirane-Jessel, Nadia; Kuchler-Bopp, Sabine

2014-03-01

248

The deposition of AgCl into tubules of the human tooth dentine  

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The deposition of AgCl in the human tooth dentine was studied as a function of the time and dc electrical field using a scanning electron microscope and by measurements of the frequency-dependent complex dielectric constant. Dielectric properties of the tooth dentine can be well described by the model which was recently developed for the dielectric response of hydrating porous cement paste. The fractal dimension of the tooth dentine was determined by the electron microscopy and dielectric spectroscopy techniques.

Levstik, A.; Leskovec, J.; Filipic, C.; Kutnjak, Z.; Zeks, B.; Kordas, M.

2001-03-01

249

Immunohistochemical Examination for the Distribution of Podoplanin-Expressing Cells in Developing Mouse Molar Tooth Germs  

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We recently reported the expression of podoplanin in the apical bud of adult mouse incisal tooth. This study was aimed to investigate the distribution of podoplanin-expressing cells in mouse tooth germs at several developing stages. At the bud stage podoplanin was expressed in oral mucous epithelia and in a tooth bud. At the cap stage podoplanin was expressed on inner and outer enamel epithelia but not in mesenchymal cells expressing the neural crest stem cell marker nestin. At the early bell...

Imaizumi, Yuri; Amano, Ikuko; Tsuruga, Eichi; Kojima, Hiroshi; Sawa, Yoshihiko

2010-01-01

250

Comparative study on the effect of ethnicity on wisdom tooth eruption  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The current knowledge base for evaluating the influence of ethnic origin on wisdom tooth eruption is still inadequate. We therefore analyzed and compared the chronology of wisdom tooth eruption in three ethnic populations German, Japanese, and black South African based on evidence from 2,482 conventional orthopantomograms. The investigated German population ranked in the middle in terms of the age of wisdom tooth eruption. The black South African population was the fastest and the Japanese po...

Olze, Andreas; Niekerk, Piet; Ishikawa, T.; Zhu, B. L.; Schulz, Ronald; Maeda, H.; Schmeling, Andreas

2007-01-01

251

Prevalence of tooth wear among 16-year-old secondary school children in Kota Bharu, Kelantan  

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Full Text Available Tooth wear is the non-carious loss of tooth tissue due to attrition, erosion and/or abrasion. The amount of wear that accelerates physiological tooth wear is referred as pathological tooth wear. This study aims to determine the prevalence and mean scores according to mouth quadrant of raw tooth wear (RTW and pathological tooth wear (PTW and investigate sex association with PTW among 16-year-old secondary school children in Kota Bharu, Kelantan. This cross-sectional study involves 688 participants randomly selected from eight government secondary schools. The Smith and Knight Tooth Wear Index (TWI was used. Data were analyzed using a simplified Microsoft Excel program developed based on the index to quantify PTW. Bar graphs were plotted to highlight the mean scores according to mouth quadrant. About 44% of participants were male and 56% were female. The prevalence of RTW and PTW among subjects was 100% and 20.1% respectively. It was found that 32.8% of tooth surfaces were affected with RTW and 0.7% of study subjects already had exposed dentine. The most affected quadrant for RTW and PTW was the upper and lower incisal quadrant respectively. Males had 92% more odds of developing tooth wear compared to females. In conclusion, all subjects have some degree of wear. About one-fifth of the study subjects were affected by PTW. The patterns of wear were similar to those encountered in the Western societies. There was statistically significant association between sex and PTW.

N.B. Saerah

2006-09-01

252

Self-directed study and carving tooth models for learning tooth morphology: perceptions of students at the University of Aberdeen, Scotland.  

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Tooth morphology has been taught at the University of Aberdeen Dental School, United Kingdom, through self-directed workshops, using online handouts and tooth models. Tooth carving sessions were recently added to introduce manual skills training through learning tooth morphology at an early stage of the dental course. The aim of this study was to assess students' perception of both teaching modalities to evaluate their usefulness and to allow further course development. The subjects of this study were first-year dental students. Students' opinions were sought upon completion of the tooth morphology sessions using a structured questionnaire that investigated their views about the effectiveness of both learning methods. The results suggest that self-directed workshops represent an effective way of learning tooth morphology; however, the students recommended further development of the course to make it more focused. Although students questioned the value of the carving sessions, they agreed that it helped to develop their manual dexterity, which was one of the main objectives of the exercise. Further review and development of the course is required in addition to follow-up of the students' performance in clinical skills to further elucidate any advantages of tooth carving to advocate it as a mode of learning. PMID:24002852

Abu Eid, Rasha; Ewan, Keith; Foley, Jennifer; Oweis, Yara; Jayasinghe, Jaya

2013-09-01

253

Single-tooth replacement: factors affecting different prosthetic treatment modalities  

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Full Text Available Abstract Background The choice between several treatment options for replacing a single missing tooth is influenced by clinical, dentist- and patient-immanent factors. This study aimed to determine the patient factors that would affect the treatment decision to replace a single missing tooth and to assess the satisfaction with several options. Method 200 volunteers involved (121 females and 79 males divided into four groups, Group A: consisted of patients with conventional fixed partial dentures or patients with resin bonded fixed partial dentures. Group B: consisted of patients who received removable partial dentures while Group C: consisted of patients who received a single implant supported crown, and a control group D: consisted of patients who received no treatment. Data were collected using a questionnaire. Results The highest percentage of males within groups (58% was within the removable prostheses category. The majority of the subjects in the study reported that the main reason for replacing a missing tooth was for esthetic and function. Most important factor affecting the choice between treatment modalities was damaging the neighboring teeth. Pain, post operative sensitivity and dental phobia were important factors in choosing the prosthesis type and affected the control group patients not to have any treatment. The highest satisfaction percentage among groups studied was recorded for dental implants then FPD groups, while the least percentage were in both the control and RPD groups, for all aspects of function, esthetic and speech efficiency. Conclusions The final choice between FPD, RPD and implant depended on several factors which affected the decision making; among these is cost and patients' awareness of the different treatment options.

Al-Quran Firas A

2011-12-01

254

A model for predicting wear rates in tooth enamel.  

Science.gov (United States)

It is hypothesized that wear of enamel is sensitive to the presence of sharp particulates in oral fluids and masticated foods. To this end, a generic model for predicting wear rates in brittle materials is developed, with specific application to tooth enamel. Wear is assumed to result from an accumulation of elastic-plastic micro-asperity events. Integration over all such events leads to a wear rate relation analogous to Archard?s law, but with allowance for variation in asperity angle and compliance. The coefficient K in this relation quantifies the wear severity, with an arbitrary distinction between 'mild' wear (low K) and 'severe' wear (high K). Data from the literature and in-house wear-test experiments on enamel specimens in lubricant media (water, oil) with and without sharp third-body particulates (silica, diamond) are used to validate the model. Measured wear rates can vary over several orders of magnitude, depending on contact asperity conditions, accounting for the occurrence of severe enamel removal in some human patients (bruxing). Expressions for the depth removal rate and number of cycles to wear down occlusal enamel in the low-crowned tooth forms of some mammals are derived, with tooth size and enamel thickness as key variables. The role of 'hard' versus 'soft' food diets in determining evolutionary paths in different hominin species is briefly considered. A feature of the model is that it does not require recourse to specific material removal mechanisms, although processes involving microplastic extrusion and microcrack coalescence are indicated. PMID:24953823

Borrero-Lopez, Oscar; Pajares, Antonia; Constantino, Paul J; Lawn, Brian R

2014-09-01

255

Inversion voltammeter definition of heavy metals in tooth pastes  

International Nuclear Information System (INIS)

Electrochemical behaviour of some heavy metals at their combined presence is studied by voltammetric method with use of graphite content sensor. The method of determination of Hg, Pb, Cd, Cu, and Zn in the tooth pastes, based on transfer of hallmark in a solution and voltammeter diagram registration is developed. Duration of the analysis (3 collateral hallmarks) makes no more than 1.5 h. An error - 10-15 % at the contents of determined elements of the (1-5) x 10-4 %

256

Tooth Detectives: Determining the Diets of Extinct Animals  

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In this two-part activity students examine the teeth of living mammals to try to determine the animal's feeding habits and then apply skills learned to the interpretation of the diet of extinct animals. During this activity students will recognize that teeth display a variety of shapes, and that tooth shapes are correlated with specific ways of obtaining and processing food. They will be able to recognize the dietary habits of living animal species through the examination of their teeth, and hypothesize what the diets of extinct animals were through the examination of fossil teeth.

Westgate, James

257

Three-dimensional analysis of mandibular growth and tooth eruption  

DEFF Research Database (Denmark)

Normal and abnormal jaw growth and tooth eruption are topics of great importance for several dental and medical disciplines. Thus far, clinical studies on these topics have used two-dimensional (2D) radiographic techniques. The purpose of the present study was to analyse normal mandibular growth and tooth eruption in three dimensions based on computer tomography (CT) scans, extending the principles of mandibular growth analysis proposed by Bjork in 1969 from two to three dimensions. As longitudinal CT data from normal children are not available (for ethical reasons), CT data from children with Apert syndrome were employed, because it has been shown that the mandible in Apert syndrome is unaffected by the malformation, and these children often have several craniofacial CT scans performed during childhood for planning of cranial and midface surgery and for follow-up after surgery. A total of 49 datasets from ten children with Apert syndrome were available for study. The number of datasets from each individual ranged from three to seven. The first CT scan in each of the ten series was carried out before 1 year of age, and the ages for the 49 scans ranged from 1 week to 14.5 years. The mandible and the teeth were segmented and iso-surfaces generated. Landmarks were placed on the surface of the mandible, along the mandibular canals, the inner contour of the cortical plate at the lower border of the symphysis menti, and on the teeth. Superimposition of the mandibles in the longitudinal series was performed using the symphysis menti and the mandibular canals as suggested by Bjork. The study supported the findings of stability of the symphysis menti and the mandibular canals as seen in profile view previously reported by Bjork & Skieller in 1983. However, the mandibular canals were, actually, relocated laterally during growth. Furthermore, the position of tooth buds remained relatively stable inside the jaw until root formation started. Eruption paths of canines and premolars were vertical, whereas molars erupted in a lingual direction. The 3D method would seem to offer new insight into jaw growth and tooth eruption, but further studies are needed.

Darvann, Tron Andre; Larsen, Per

2005-01-01

258

Hedgehog signaling is required at multiple stages of zebrafish tooth development  

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Full Text Available Abstract Background The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood. Results We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region. Conclusion We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution.

Stock David W

2010-11-01

259

Analysis of stress state of toothed ring of flexspline by means the BEM  

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Full Text Available Purpose: The paper presents an analysis of the influence of design features of the flexspline in a harmonic drive, such as the relative radial deformation, the relative coating thickness and the design features of the basic rack tooth profile, on stress values in the bottom lands of a toothed ring.Design/methodology/approach: In numerical calculations, the software developed at the Faculty of Transport of the Silesian University of Technology was used. The program automatically generates a profile of the flexspline and a boundary elements mesh on the grounds of the flexspline and working tool assigned parameters. In the analysis of the state of stress, the boundary element method (BEM was applied.Findings: A decreased value of the curve radius of the head of the basic rack tooth profile results in a change in the width of the tooth bottom land, shortening of the transition curve in the tooth base and a reduction of the tooth thickness at its base, which in turn leads to increased values of stress. Yet, the influence of the relative curve radius of the head of the basic rack tooth profile on the stress value is insignificant. The increase of the torque and relative coating thickness for different value of the curve radius of the head of the basic rack tooth profile cause an increase of stress in the bottom lands of the toothed ring.Research limitations/implications: The paper presents strength calculations for the teeth in toothed ring of a flexspline of a double harmonic drive by means of boundary elements method (BEM. The results of numerical calculations correspond in terms of their quality to the results presented in the literature, which were calculated by finite element method (FEM.Originality/value: In the analysis of the state of stress of toothed ring of flexspline, the boundary element method (BEM was applied.

P. Fol?ga

2013-01-01

260

Treatment of tooth fracture by medium energy CO2 laser and DP-bioactive glass paste: thermal behavior and phase transformation of human tooth enamel and dentin after irradiation by CO2 laser.  

Science.gov (United States)

Acute trauma or trauma associated with occlusal disharmony can produce tooth crack or fracture. Although several methods are proposed to treat the defect, however, the prognosis is generally poor. If the fusion of a tooth fracture by laser is possible it will offer an alternative to extraction or at least serve as an adjunctive treatment in the reconstruction. The responses of soft tissues to lasers of different wavelengths are fairly well known, but the reactions of hard tissues are still to be understood. The purpose of this research was to study the feasibility of using a medium energy continuous-wave CO(2) laser and a low melting-point bioactive glass to fuse or bridge tooth fractures. The present report is focused on the first part of the research, the analysis of changes in laser-irradiated human tooth enamel/dentin by means of X-ray diffractometer (XRD), Fourier-transforming infrared spectroscopy (FTIR), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and scanning electron microscopy (SEM). After CO(2) laser irradiation, there were no marked changes in the X-ray diffraction pattern of the enamel when compared to that before laser treatment. However, a small peak belonging to alpha-TCP appeared at the position of 2theta=30.78 degrees C. After being treated with CO(2) laser, the dentin showed much sharper peaks on the diffraction patterns because of grain growth and better crystallinity. alpha-TCP and beta-TCP were identified after laser treatment. In the FTIR analysis, an HPO(4)(-2) absorption band was noted before laser treatment disappeared after the irradiation. No significant change in the absorption band of HPO(4)(-2) was found on the FTIR curves of enamel after laser treatment. The results of DTA/TGA indicated that loss of water and organic materials occurred in both enamel and dentin after laser treatment. Under SEM, melting and resolidification occurred in both enamel and dentin by medium energy of CO(2) laser. This implies that using a continuous-wave CO(2) laser of medium energy density to fuse a low melting-point bioactive glass to the enamel/dentin is possible. We believe these phase changes and thermal data can make a useful guide for future studies on the thermal interaction and bridging mechanism between the bioactive glass and enamel/dentin under CO(2) laser irradiation. PMID:15348019

Lin, C P; Lee, B S; Kok, S H; Lan, W H; Tseng, Y C; Lin, F H

2000-06-01

 
 
 
 
261

A comparative study of two methods of dental pulp extraction for genetic fingerprinting.  

Science.gov (United States)

Extracting dental DNA for identification purposes is usually performed after crushing the tooth. The main disadvantage of this method is that the tooth is completely destroyed so further radiographic, anatomical or biochemical studies are no longer possible. We compared the quantities of DNA obtained by crushing the tooth and by removing pulp by standard endodontic access with trepanation of the occlusal surface and amplified DNA micro-satellites. In the series of crushed teeth, insufficient material for amplification was obtained in 78% of cases and a complete profile was obtained in only 9% of cases. Conversely, for the teeth prepared by trepanation, the profile was complete in 75% of cases and the DNA quantity was insufficient in only 3% of cases. Trepanation thus produced superior results in terms of quantity of DNA and the quality of the genetic profiles. Furthermore, it was a conservative procedure that allowed further analyses on the tooth. PMID:20663623

Tilotta, Françoise; Brousseau, Philippe; Lepareur, Elise; Yasukawa, Kazutoyo; de Mazancourt, Philippe

2010-10-10

262

Comparison of the effect of thermal stresses on tooth-colored posts, cores and tooth structures by finite element analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Objectives: The aims of this study were to analyze the influence of cold heat flow in all ceramic crown material, composite core, zirconium and glass fiber reinforced composite post materials, resin based luting cement and root dentin; and to compare these two tooth-colored post systems about their temperature and thermal stress distributions.
Materials and Methods: A 3-dimesional finite element model of maxillary left canine tooth was constructed. All ceramic crown, composite core, tooth dentin, post and bone were modeled. In the first part of this study, initial body temperature was assumed to be 36.5°C and the outer temperature was reduced to 0°C for 5 secs. In the second part, the thermal stress was calculated as a result of temperature change. For the analysis, 7 nodes of the finite element model were selected and heat flow, temperature and thermal stres on these nodes were evaluated.
Results: Mean temperature value was 15.75 °C for GFRC post model and 15.47 °C for Zr post model. The maximum von Mises stress was obtained at the node C in both post systems. In general, thermal stress was observed on the cervical part of all-ceramic crown and there was an interface between root dentin-composite core and post material. The temperature gradient of the GFRC post was smaller than that of the zirconia post.
Conclusions: Within the limitation of this study, zirconia posts produced greater stress than GFRC posts. Temperature changes had more effect on the post-cement interface and cervical areas than on the other areas.

Levent Nalbant

2012-04-01

263

Toothbrushing after an erosive attack: will waiting avoid tooth wear?  

Science.gov (United States)

The purpose of this study was to determine if storage for up to 4 h in human saliva results in a decrease of erosive tooth wear (ETW) and in an increase of surface microhardness (SMH) of enamel samples after an erosive attack with subsequent abrasion. Furthermore, we determined the impact of individual salivary parameters on ETW and SMH. Enamel samples were distributed into five groups: group 1 had neither erosion nor saliva treatment; groups 2-5 were treated with erosion, then group 2 was placed in a humid chamber and groups 3-5 were incubated in saliva for 30 min, 2 h, and 4 h, respectively. After erosion and saliva treatments, all groups were treated with abrasion. Surface microhardness and ETW were measured before and after erosion, incubation in saliva, and abrasion. Surface microhardness and ETW showed significant changes throughout the experiment: SMH decreased and ETW increased in groups 2-5, regardless of the length of incubation in saliva. The results of groups 3-5 (exposed to saliva) were not significantly different from those of group 2 (not exposed to saliva). Exposure of eroded enamel to saliva for up to 4 h was not able to increase SMH or reduce ETW. However, additional experiments with artificial saliva without proteins showed protection from erosive tooth wear. The recommendation to postpone toothbrushing of enamel after an erosive attack should be reconsidered. PMID:25131337

Lussi, Adrian; Lussi, Jonas; Carvalho, Thiago S; Cvikl, Barbara

2014-10-01

264

Charcot-Marie-Tooth disease: genetic and rehabilitation aspects  

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Full Text Available Charcot-Marie-Tooth hereditary motor and sensory neuropathy refers to a group of disorders characterized by a chronic motor and sensory polyneuropathy. Typical cases have distal muscle weakness and peroneal atrophy often associated with mild to moderate sensory loss, depressed tendon reflexes, and pes cavus. Hereditary neuropathies are categorized by mode of inheritance and chromosomal locus. The diagnosis is based on family history, characteristic findings on physical examination, EMG, nerve conduction velocity testing, and occasionally on nerve biopsy. The disorder shows allelic and non-allelic genetic heterogeneity, thus mutations of different genes leading to the same clinical features. Also, different mutations of the same gene may lead to different phenotypes. Molecular genetic testing is available in clinical laboratories for diagnosis of 7 subtypes of the disease. Genetic counseling and risk assessment depend on the inheritance. We present two cases with Charcot-Marie-Tooth type 1 and type 2 respectively. There is no cure for the disorder, although physical therapy and moderate activity are often recommended to maintain muscle strength and endurance.

Mariana CEVEI

2008-05-01

265

Ultrastructural organization and micromechanical properties of shark tooth enameloid.  

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The outer part of shark teeth is formed by the hard and mineral-rich enameloid that has excellent mechanical properties, which makes it a very interesting model system for the development of new bio-inspired dental materials. We characterized the microstructure, chemical composition and resulting local mechanical properties of the enameloid from teeth of Isurus oxyrinchus (shortfin mako shark) by performing an in-depth analysis using various high-resolution analytical techniques, including scanning electron microscopy, qualitative energy-dispersive X-ray spectroscopy and nanoindentation. Shark tooth enameloid reveals an intricate hierarchical arrangement of thin (50-80nm) and long (>1?m) crystallites of fluoroapatite with a high degree of structural anisotropy, which leads to exceptional mechanical properties. Both stiffness and hardness are surprisingly homogeneous in the shiny layer as well as in the enameloid: although both tooth phases differ in structure and composition, they show almost no orientation dependence with respect to the loading direction of the enameloid crystallites. The results were used to determine the structural hierarchy of shark teeth, which can be used as a base for establishing design criteria for synthetic bio-inspired and biomimetic dental composites. PMID:24797528

Enax, Joachim; Janus, Anna M; Raabe, Dierk; Epple, Matthias; Fabritius, Helge-Otto

2014-09-01

266

Development of the canine tooth in the beagle  

International Nuclear Information System (INIS)

The growth of the crown and root in the canine tooth of beagle dogs were observed macroscopically and radiographically, and changes of occlusion with age were investigated. Completion of growth in the crown of the canine tooth was observed in both mandible and maxilla, and its eruption was accompanied by development of the dental root. The permanent canine erupted on the lingual side of deciduous canine in the mandible, and on the mesial side of the deciduous canine in the maxilla. Movement of the permanent canine to normal occlusal position(buccal direction in mandibular canine, and distal direction in maxillary canine)was followed by the loss of the deciduous canine. Coexistence of the permanent and deciduous canines occurred for about 2.4 weeks in the maxilla and about 1.4 weeks in the mandible, on average. Macroscopically, the growth of the permanent canine was completed by 33 weeks of age in the mandible and about 34 weeks of age in the maxilla. The mature root of the permanent canine was recognized radiographically at about 43 weeks of age in the mandible and 47 weeks of age in the maxilla

267

Disturbed tooth formation by 60Co-gamma-ray radiation  

International Nuclear Information System (INIS)

The molar of guinea pigs was irradiated with 60Co-#betta# ray for daily observations of the manifestation of disturbed tooth formation by microradiography and the time registration by tetracycline-labelling. Irradiation first injured young blast cells of the dentin in the growth phase, dental pulp cells, and cells of the enamel. The portion composed of injured cells formed a depressed ''constriction'' from the dental pulp side toward the border between the enamel and dentin. The cells of the enamel injured by irradiation in the growth phase later formed a very thin irregular stroma. In contrast, cells in the differentiation or subsequent phase at the time of irradiation and cells probably having started to grow after irradiation proceeded with formation of a normal stroma and calcification. No uniform relation was obtained between the histological staining of the organic stroma of normal or abnormal dentin and calcification. Labelling with tetracycline revealed that the irradiation conditions in the present study provoked hardly any changes in the speed of tooth eruption. (Chiba, N.)

268

21 CFR 872.3900 - Posterior artificial tooth with a metal insert.  

Science.gov (United States)

...Posterior artificial tooth with a metal insert. (a) Identification...posterior artificial tooth with a metal insert is a porcelain device...percent or greater gold and metals of the platinum group intended...occlusion (bite). (b) Classification. Class I (general...

2010-04-01

269

Influence of dental materials on the tooth structure finite elements method study  

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Full Text Available The purpose of this study is to evaluate the behavior of dental materials used in tooth restoration and the effects of these materials on intact and restaurated tooth structure. Our study uses finite elements method (FEM owing to its multiple advantages.

Ligia Cristina Brezeanu

2011-12-01

270

Tooth brushing frequency in Mexican schoolchildren and associated socio-demographic, socioeconomic, and dental variables  

Science.gov (United States)

Background Tooth brushing (with fluoridated toothpaste) is the most cost-effective intervention in dentistry and it is widely recommended to preserve good oral health. We aimed to determine the frequency of tooth brushing and the variables associated with this practice in schoolchildren living in southeast Mexico. Material/Methods A cross-sectional study was carried out in 1644 schoolchildren, 6 to 13 years old. Questionnaires with socio-demographic, socioeconomic, and dental variables were administered to mothers/guardians of children. The dependent variable was the frequency of tooth brushing, which was categorized as 0 = tooth brushing less than once a day and 1 = tooth brushing at least once a day. A logistic regression model was used to evaluate the final results. Results Mean age was 9.06±2.02 years and 49.1% were girls. The prevalence of tooth brushing at least once a day was 49.8%. In the multivariate model, characteristics related to tooth brushing frequency (p<0.05) were: older age (OR=1.11), being female (OR=1.64), having a larger family (OR=0.87), having had a visit to a dentist during the year preceding the study (OR=1.37), and having had fluoride applications by a professional (OR=1.39). Conclusions The results suggested that different variables (demographic, socioeconomic and dental) are associated with the frequency of tooth brushing. Family size (proxy variable for socioeconomic status) may indicate certain oral health inequalities in this population. PMID:24907713

Casanova-Rosado, Alejandro Jose; Medina-Solis, Carlo Eduardo; Casanova-Rosado, Juan Fernando; Vallejos-Sanchez, Ana Alicia; Minaya-Sanchez, Mirna; Mendoza-Rodriguez, Martha; Marquez-Rodriguez, Sonia; Maupome, Gerardo

2014-01-01

271

The tooth-worm: historical aspects of a popular medical belief.  

Science.gov (United States)

The concept of a tooth-worm, which according to popular belief, caused caries and periodontitis, has existed in diverse cultures and across the ages. During the Enlightenment, however, the theory of the tooth-worm was assigned by medical doctors almost exclusively to superstition. Even so, the idea that toothache was caused by gnawing worms held on even into this century. There were many different ideas with regard to the appearance of tooth-worms. In England, for instance, it was thought that the tooth-worm looked like an eel. In Northern Germany, people supposed the tooth-worm to be red, blue, and gray and in many cases the worm was compared to a maggot. The gnawing worm was held responsible for many evils and, in particular, was blamed for toothache provoked by caries. The question is discussed of how the belief in the existence of the tooth-worm in former times can be explained. In popular medicine, numerous therapies were applied in order to eradicate the tooth-worm. In addition to the fumigations with henbane seeds, which allowed the "tooth-worm" to develop in the form of burst seeds, there were also magical formulas and oaths. PMID:10522185

Gerabek, W E

1999-03-01

272

On optimization of internal/external spur gears tooth bending strength  

DEFF Research Database (Denmark)

Gear fatigue strength is primarily controlled by the durability and load capacity, the first is typically related to pitting damage and the second to tooth-breakage. The pitting is due to the tooth contact and the shape of the contacting surfaces, the tooth breakage is controlled by the stress level at the tooth root. As with most machine elements the design/geometry is defined in standards (ISO). The present work focuses on changing the tooth root design of both external and internal gears, in order to improve the stress concentration factor. The design changes made are compliant with the standard, i.e. the optimized gear design can mesh with a standard gear.

Pedersen, Niels Leergaard

2014-01-01

273

Tooth in nasal cavity of non-traumatic etiology: uncommon affection  

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Full Text Available Introduction: The presence of ectopic supernumerary tooth is not an uncommon fact, and the estimate is that 1% of the population is affected. However, a tooth in nasal cavity is a rare event, independently of the etiology. Objective: To report a case of a tooth in nasal cavity whose etiology is neither traumatic and nor iatrogenic. Case report: The young patient presented with a radiopaque image in nasal cavity during dental propedeutics. Upon otorhinolaryngological exams, a tooth was identified, in spite of no existence of any trauma. Surgical treatment was carried out without complications. Final Comments: The presence of tooth in nasal cavity, in spite of being uncommon, must be given special attention. The dangerous triangle of the face is a potential place of complications, therefore, the approach must be surgical even in asymptomatic patients.

Oliveira, Henrique Fernandes de

2009-06-01

274

Visualization of Tooth for Non-Destructive Evaluation from CT Images  

Energy Technology Data Exchange (ETDEWEB)

This paper reports an effort to develop 3D tooth visualization system from CT sequence images as a part of the non-destructive evaluation suitable for the simulation of endodontics, orthodontics and other dental treatments. We focus on the segmentation and visualization for the individual tooth. In dental CT images teeth are touching the adjacent teeth or surrounded by the alveolar bones with similar intensity. We propose an improved level set method with shape prior to separate a tooth from other teeth as well as the alveolar bones. Reconstructed 3D model of individual tooth based on the segmentation results indicates that our technique is a very conducive tool for tooth visualization, evaluation and diagnosis. Some comparative visualization results validate the non-destructive function of our method.

Gao, Hui; Chae, Ok Sam [Kyung Hee University, Seoul (Korea, Republic of)

2009-06-15

275

[Immediate implantation of an abutment tooth attached by a magnet in an overdenture: report of one case].  

Science.gov (United States)

A female patient, aged 59 years old, underwent immediate implantation of the abutment tooth attached by a magnet in an overdenture. The tooth recovered to normal three months later. A denture was remade and the tooth was still attached by a magnet at the same time. The overdenture fixed well 20 months later, and the tooth was normal. Results of X-ray examination was negative. PMID:18784893

Zhou, Li-jing

2008-08-01

276

Comparison between observed children's tooth brushing habits and those reported by mothers  

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Full Text Available Abstract Background Information bias can occur in epidemiological studies and compromise scientific outcomes, especially when evaluating information given by a patient regarding their own health. The oral habits of children reported by their mothers are commonly used to evaluate tooth brushing practices and to estimate fluoride intake by children. The aim of the present study was to compare observed tooth-brushing habits of young children using fluoridated toothpaste with those reported by mothers. Methods A sample of 201 mothers and their children (aged 24-48 months from Montes Claros, Brazil, took part in a cross-sectional study. At day-care centres, the mothers answered a self-administered questionnaire on their child's tooth-brushing habits. The structured questionnaire had six items with two to three possible answers. An appointment was then made with each mother/child pair at day-care centres. The participants were asked to demonstrate the tooth-brushing practice as usually performed at home. A trained examiner observed and documented the procedure. Observed tooth brushing and that reported by mothers were compared for overall agreement using Cohen's Kappa coefficient and the McNemar test. Results Cohen's Kappa values comparing mothers' reports and tooth brushing observed by the examiner ranged from poor-to-good (0.00-0.75. There were statistically significant differences between observed tooth brushing habits and those reported by mothers (p Conclusions In general, there was low agreement between observed tooth brushing and mothers' reports. Moreover, the different methods of estimation resulted in differences in the frequencies of tooth brushing habits, indicative of reporting bias. Data regarding children's tooth-brushing habits as reported by mothers should be considered with caution in epidemiological surveys on fluoridated dentifrice use and the risk of dental fluorosis.

Pordeus Isabela A

2011-09-01

277

Diabetes and Tooth Loss in a National Sample of Dentate Adults Reporting Annual Dental Visits  

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Full Text Available IntroductionPeriodontal disease has been associated with tooth loss and reported as more prevalent among people with diabetes than among those without diabetes. Having an annual dental examination is a national goal of Healthy People 2010. Our objective was to examine whether an association exists between diabetes and tooth loss among a population reporting an annual dental visit.MethodsWe used data from the 2004 Behavioral Risk Factor Surveillance System to examine the association between self-reported diabetes and tooth removal due to decay or periodontal disease among 155,280 respondents reporting a dental visit within the past year. We calculated prevalence estimates, odds ratios, and 95% confidence intervals. Multiple logistic regression allowed for adjustment.ResultsThe overall prevalence of tooth removal among the people in the study was 38.3%. People with diabetes had a significantly higher prevalence of tooth removal. In a multivariable model adjusting for selected covariates, respondents with diabetes were 1.46 times as likely (95% CI, 1.30–1.64 to have at least one tooth removed than respondents without diabetes. A stronger association between diabetes and tooth loss was observed among people in the younger age groups than among those in the older age groups.ConclusionEven among people reporting a recent dental visit, diabetes was independently associated with tooth loss. Multidisciplinary efforts are needed to raise awareness of the risk of tooth loss among younger people with diabetes. Good oral hygiene as well as annual dental examinations are important for preventing tooth loss.

Julie M. Kapp, PhD, MPH

2007-07-01

278

Wnt signaling during tooth replacement in zebrafish (Danio rerio): pitfalls and perspectives  

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The canonical (?-catenin dependent) Wnt signaling pathway has emerged as a likely candidate for regulating tooth replacement in continuously renewing dentitions. So far, the involvement of canonical Wnt signaling has been experimentally demonstrated predominantly in amniotes. These studies tend to show stimulation of tooth formation by activation of the Wnt pathway, and inhibition of tooth formation when blocking the pathway. Here, we report a strong and dynamic expression of the soluble Wnt inhibitor dickkopf1 (dkk1) in developing zebrafish (Danio rerio) tooth germs, suggesting an active repression of Wnt signaling during morphogenesis and cytodifferentiation of a tooth, and derepression of Wnt signaling during start of replacement tooth formation. To further analyse the role of Wnt signaling, we used different gain-of-function approaches. These yielded disjunct results, yet none of them indicating enhanced tooth replacement. Thus, masterblind (mbl) mutants, defective in axin1, mimic overexpression of Wnt, but display a normally patterned dentition in which teeth are replaced at the appropriate times and positions. Activating the pathway with LiCl had variable outcomes, either resulting in the absence, or the delayed formation, of first-generation teeth, or yielding a regular dentition with normal replacement, but no supernumerary teeth or accelerated tooth replacement. The failure so far to influence tooth replacement in the zebrafish by perturbing Wnt signaling is discussed in the light of (i) potential technical pitfalls related to dose- or time-dependency, (ii) the complexity of the canonical Wnt pathway, and (iii) species-specific differences in the nature and activity of pathway components. Finally, we emphasize the importance of in-depth knowledge of the wild-type pattern for reliable interpretations. It is hoped that our analysis can be inspiring to critically assess and elucidate the role of Wnt signaling in tooth development in polyphyodonts. PMID:25339911

Huysseune, Ann; Soenens, Mieke; Elderweirdt, Fien

2014-01-01

279

Evaluation of Microleakage in Composite-Composite and Amalgam-Composite Interfaces in Tooth with Preventive Resin Restoration (Ex-viva  

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Full Text Available Objective: This study addresses the question of whether conservative methods of restoration may be applied efficaciously in permanent posterior teeth with proximal lesions and intact occlusal preventive resin restoration (PRR. The purpose of the present study was to assess the microleakage at amalgam-composite interface and composite-composite interface in permanent tooth with PRR.Materials and Methods: Thirty-five premolar teeth extracted for orthodontic reasons were selected. The occlusal surfaces were sealed as preventive resin restoration. Then the teeth were stored in incubator for 6 months. After this period, two single boxes were prepared in mesial and distal surfaces in each tooth and filled with amalgam. Another class I composite restoration was prepared in occlusal surface in contact with the first PRR. Then samples were thermocycled and marginal leakage was assessed by the degree of dye penetration on sections of the restored teeth.Friedman and Wilcoxon signed-rank tests served for statistical analyses.Results: In 51.4% of amalgam-composite interfaces the dye reached the pulpal wall. The corresponded figures for amalgam-tooth and composite-composite interfaces were 31.4% and 14.3%, respectively. The differences in microleakage among the three interfaces were statistically significant (P<0.05.Conclusion: In the teeth restored with PRR technique, restoring proximal lesions with a conservative technique may lead to favorable results concerning microleakage.

H. Afshar

2012-01-01

280

Immediate, non-submerged, root-analogue zirconia implant in single tooth replacement.  

Science.gov (United States)

This report demonstrates the successful clinical use of a modified root-analogue zirconia implant for immediate single tooth replacement. A right maxillary premolar was removed and a custom-made, root-analogue, roughened zirconia implant with macro-retentions in the interdental space was fabricated and placed into the extraction socket 4 days later. Four months after root implantation a composite crown was cemented. No complications occurred during the healing period. An excellent esthetic and functional result was achieved with the composite crown. No clinically noticeable bone resorption or soft-tissue recession was observed at 26 months follow up. Significant modifications such as macro-retentions seem to indicate that primary stability and excellent osseointegration of immediate root-analogue zirconia implants can be achieved, while preventing unesthetic bone resorption. The macro-retentions must be limited to the interdental space to avoid fracture of the thin buccal cortex. This successful case warrants further clinical research in well controlled trials. PMID:18272340

Pirker, W; Kocher, A

2008-03-01

 
 
 
 
281

Recurrent epistaxis caused by an intranasal supernumerary tooth in a young adult  

Science.gov (United States)

Patient: Male, 27 Final Diagnosis: Recurrent epistaxis Symptoms: Nasal bleeding Medication: — Clinical Procedure: — Specialty: Pediatrics and Neonatology Objective: Congenital defects/diseases Background: Recurrent epistaxis is a common disorder among children and young adults. We report an unusual cause, intranasal supernumerary tooth causing friction with Little’s area of the nasal septum. Case Report: A 22-year-old male presented with recurrent, mild, unilateral left-sided epistaxis once to twice per month for 3 years. This usually occurred after minor nasal trauma or rubbing his nose. The patient also suffered from recurrent tonsillitis. There was neither history of blood transfusion or nasal packing, nor a history suggestive of bleeding diathesis. Anterior rhinoscopy revealed ivory white nasal mass antero-inferiorly in the left nasal cavity touching Little’s area. There was no bleeding. Nasal endoscopy showed a white cylindrical bony mass 1 cm long arising from the floor of the nose, with no attachment to the nasal septum or the lateral wall of the nose. Examination of the right nasal cavity was unremarkable. Conclusions: Nasal teeth result from the ectopic eruption of supernumerary teeth and may cause a variety of symptoms including recurrent epistaxis. Their clinical and radiologic presentation is so characteristic that their diagnosis is not difficult. CT scan is helpful in planning management. Early extraction prevents further complications and prevents further attacks of epistaxis. PMID:25031783

Al Dhafeeri, Hamed O.; Kavarodi, Abdulmajid; Shaikh, Khalil Al; Bukhari, Ahmed; Hussain, Omair Al; Baramawy, Ahmed El

2014-01-01

282

Tooth enamel electron spin resonance dosimetry of people living in the area with lime tobacco custom  

International Nuclear Information System (INIS)

Objective: To study the effect of the custom of long term chewing lime tobacco on human tooth enamel electron spin resonance (ESR) dosimetry. Methods: A total of 20 enamel samples from lingual parts of adults teeth collected in Bombay, India were obtained by mechanical method. Some enamel samples from Japanese adults were extracted and 10 mixed samples were prepared. Enamel samples were exposed to different doses of 60Co ?-rays several times, and ESR spectra were measured after exposure. Results: ESR background signals of 9 Bombay samples were found 1.5-3.3 times higher than those of Japanese mixed samples. The ?-ray dose responses of dosimetric signal with higher background level were a little lower, and the average sensitivity was (0.42±0.03) mGy, which was close to that of Japanese mixed samples. Conclusions: The average level of background signals of Bombay samples was much higher than that of other non-chewing tobacco area, which was possibly caused by tobacco area, which was possibly caused by tobacco lime, the main component in chewing tobacco productions, and it would help to explore its special influences on ESR, and improve dose reconstruction in accuracy. (authors)

283

Comparison of Intact dental pulp tissue characteristics, Comparison between primary and permanent tooth in dog  

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Full Text Available Introduction: Responses of dental pulp in primary and permanent tooth are different to pulp therapy, trauma, caries, dehydration, pulp tester and dental materials. The reactions of primary dental pulp in compare with permanent dental pulp are different.Can these various reactions be attributed to different histological characteristics in two groups of teeth? The aim of this study is comparison of histological characteristics between dental pulps in two groups of teeth of dog.Methods and Materials: 20 primary and 20 permanent teeth of two dogs were selected. Forty teeth were extracted under general anesthesia. 1-2 millimeter of apices of roots were cut and immersed in 10% formaldehyde solution. Then the samples were sent to oral histological lab for staining and sliding. Oral pathologist examined the histology of dental pulps and reported the results. The data of study were analyzed by SPSS software 11.5. Then data were compared with Mann-Whitney and t-test. Finally findings were reported.Results: The relative frequency of fibroblasts, mesenchymal undifferentiating cells, blood vessels, collagen and nerve fibers and immune cells in primary and permanent dental pulp in dog had no significant difference (p value

SE Jabbarifar

2007-01-01

284

Effect of fluorides from various restorative materials on remineralization of adjacent tooth: An in vitro study  

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Full Text Available The aim of the study was to evaluate the extent of surface zone remineralization and the effect of fluoride at the inter-proximal adjacent tooth surface, using restorative materials FusionAlloy, Ketac-Fil and Heliomolar. Ninety extracted molar teeth were used of which 45 were placed in artificial caries for 10 weeks. The remaining 45 teeth were filled with the respective restorative materials, mounted with the artificial carious teeth in proximal contact with plaster and placed in artificial saliva for a period of 28 days. Finally, sectioning of artificially carious teeth was done mesio-distally and observed under the optical microscope and scanning electron microscope. Comparison among the groups was done by one-way analysis of variance [ANOVA] and Fischer?s F test. Intercomparison between the groups was done by using Dunnett?s t-test. Results obtained from transmitted electron microscopic and scanning electron microscopic observations were almost similar with the Ketac-Fil and Heliomolar showing better results in surface zone remineralization compared to FusionAlloy. Also, Ketac-Fil is a good material in releasing fluoride to remineralize enamel when compared to Heliomolar and FusionAlloy. Thus, it can be used mainly in class II cavity restorations of primary and permanent dentitions due to the potential ability of fluoride containing glass ionomer cements and composite resins to remineralize incipient carious lesions on adjacent teeth.

Baliga M

2010-06-01

285

Tooth wear in patients submitted to bariatric surgery  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Cirurgia bariátrica pode provocar freqüentes episódios de vômito e refluxo gastroesofágico o que promove o contato dos ácidos gástricos com os dentes fazendo que haja perda irreversível de estrutura dental. Este estudo teve como objetivo avaliar a prevalência de desgaste dentário em pacientes bariát [...] ricos. Foram examinados 125 pacientes em um Hospital Público de São Luís, MA no período de julho a outubro de 2010, distribuídos em pacientes que já tinham sidos submetidos à cirurgia bariátrica há pelo menos 6 meses (Grupo bariátrico), obesos mórbidos que estavam na lista de espera para esta cirurgia (Grupo obeso) e por pacientes que esperavam por consulta médica ambulatorial em outros setores (Grupo controle). Os pacientes responderam a um questionário investigativo e foram examinados clinicamente utilizando o “Basic Erosive Wear Examination” - BEWE (Índice Básico do Desgaste Erosivo) que permite a classificação da severidade das lesões não-cariosas e avaliação de risco. Todos os pacientes apresentaram algum grau de desgaste dentário em diferentes níveis. No entanto, a presença de LDNC (lesão dental não-cariosa) estava associada ao grupo que o paciente pertencia. O grupo bariátrico apresentou maior prevalência e nível de risco em relação às LDNC’s estatisticamente significante quando comparado aos outros grupos, seguido pelo grupo de obeso e controle. Refluxo e vômito parecem não influenciar positivamente nas LDNC. Abstract in english Bariatric surgery may cause frequent vomiting episodes and gastroesophageal reflux, which promote the contact of gastric acids with the teeth leading to irreversible loss of tooth structure. The aim of this study was to assess prevalence of tooth wear in bariatric patients. One hundred and twenty-fi [...] ve patients were examined at a Public Hospital in São Luis, MA, Brazil, between July and October 2010, being patients who had already been submitted to the bariatric surgery at least 6 months previously (Bariatric group), morbidly obese patients who were on the waiting list for this surgery (Obese group) and patients who were waiting for ambulatory medical care in other sectors (Control group). The patients answered an investigative questionnaire and were clinically examined using the Basic Erosive Wear Examination (BEWE) scoring system, which allows the classification of the severity of noncarious dental lesions (NCDL) and evaluation of risk. All patients presented some degree of tooth wear at different levels. However, the presence of NCDL was associated with the group to which the patient belonged. The bariatric patients showed higher prevalence and a statistically significant level of risk with regard to NCDLs when compared with the other patients, followed by the obese and control groups. Reflux and vomiting did not seem to influence NCDL positively.

Maria do Socorro Coêlho, Alves; Fernando Alberto Costa Cardoso da, Silva; Stephanie Gomes, Araújo; Antônio Cláudio Almeida de, Carvalho; Alcione Miranda, Santos; Andrea Lúcia Almeida de, Carvalho.

286

Application of thrombin powder after tooth extraction in patients receiving anticoagulant therapy  

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Full Text Available Patients with extreme hypocoagulation, which occurs either as an effect of some diseases with coagulation deficiency or because of the anticoagulant therapy (ACT, are a risk group for oral surgery. In the last decades decision to change or interrupt ACT before and after the procedure was abandoned and more often local hemostasis was being achieved by combining chemical and biological substances. The success of the surgical hemostasis and thrombin powder combination was tested on the group of 20 patients with ACT. The results were satisfactory despite thrombin powder solubility in the moist oral environment.

Marjanovi? Marjan

2002-01-01

287

Electron spin resonance characterization of human tooth enamel response to proton, neutron, and ultraviolet radiation  

Science.gov (United States)

In this research, Continuous Wave (CW) Electron Spin Resonance (ESR) techniques and advanced pulsed ESR techniques were used to examine the response of human tooth enamel to different types of radiation and to investigate the characteristics of the radiation-induced free radicals created in tooth enamel. An examination of the response of tooth enamel to proton, neutron, and ultraviolet (UV) radiation was conducted using CW-ESR techniques. Pulsed ESR methodologies were used to examine the spatial properties of free radicals created in tooth enamel irradiated by gamma, proton, and UV radiation. The CW-ESR determined dose response of tooth enamel irradiated by 2.0 MeV protons indicated a linear dose response until approximately 2,000 Gy after which the dose response appeared to plateau. No conclusive CW-ESR determined dose response was detected for tooth enamel irradiated with either 1.02 MeV neutrons or 14.0 MeV neutrons. An examination of the relationship between tooth position in the mouth and the CW-ESR signal produced by UV radiation from sunlight indicated that front teeth should be avoided and that it is important to take tooth type, and therefore position in the mouth, into account when tooth enamel is used for radiation biodosimetry. A well-defined UV source was used to irradiate tooth enamel in order to conduct an examination of the CW-ESR signal produced. Tooth enamel irradiated by several different UV wavelengths, power levels, and total energies emitted indicated a CW-ESR signal intensity dependence on total dose, dose rate, and UV wavelength. Pulsed ESR methodologies indicated that the numbers of free radicals per cluster, the cluster radii, and the local concentrations of radicals were clearly different for gamma, proton, and UV-irradiated tooth enamel even though the predominant radical species trapped in each case was CO2-. These results indicated that pulsed ESR techniques are capable of providing information that could be used to help identify the type of radiation to which tooth enamel has been exposed.

Katanic, Janine Faith

2003-10-01

288

Radicular cyst of primary tooth associated with maxillary sinus.  

Science.gov (United States)

Radicular cyst is one of the most common odontogenic cystic lesions found in the jaws. It is inflammatory in nature and found mostly in relation to a non-vital tooth. It usually presents at a later stage in life because the formation of the cyst is the last step in the progression of inflammatory events after a periapical infection. The cyst usually goes unnoticed because of its painless nature and small size. We present the clinical, radiographic and histological characteristics of a radicular cyst along with its management. Cystic sac was removed surgically under general anaesthesia after the elevation of the mucoperiosteal flap. Histopathologically, the cystic sac was consistent with the features of a radicular cyst. Follow-up period of 21 months showed improved radiographical appearance on Coned Beam CT. Vestibular deepening was planned as a future treatment in the same region. PMID:23833085

Bahadure, Rakesh N; Khubchandani, Monika; Thosar, Nilima R; Singh, Rajeev Kumar

2013-01-01

289

Dynamin 2 in Charcot-Marie-Tooth Disease  

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Full Text Available Charcot-Marie-Tooth disease (CMT is an inherited neuronal disorder, and is induced by mutations of various genes associated with intracellular membrane traffic and cytoskeleton. A large GTPase, dynamin, which is known as a fission protein for endocytic vesicles, was identified as a gene responsible for dominant-intermediate CMT type 2B (DI-CMT2B. Of these mutants, the PH domain, which is required for interaction with phosphoinositides, was mutated in several families. Interestingly, the expression of a deletion mutant, 551?3, did not impair endocytosis, but induced abnormal accumulation of microtubules. Recent evidence has shown that dynamin 2 regulates the dynamic instability of microtubules, and 551?3 lacks this function. We propose a model for the regulation of the dynamic instability of microtubules by dynamin 2 and discuss the relationship between dynamin 2 and CMT.

Tanabe,Kenji

2012-06-01

290

Hand weakness in Charcot-Marie-Tooth disease 1X.  

LENUS (Irish Health Repository)

There have been suggestions from previous studies that patients with Charcot-Marie-Tooth disease (CMT) have weaker dominant hand muscles. Since all studies to date have included a heterogeneous group of CMT patients we decided to analyse hand strength in 43 patients with CMT1X. We recorded handedness and the MRC scores for the first dorsal interosseous and abductor pollicis brevis muscles, median and ulnar nerve compound motor action potentials and conduction velocities in dominant and non-dominant hands. Twenty-two CMT1X patients (51%) had a weaker dominant hand; none had a stronger dominant hand. Mean MRC scores were significantly higher for first dorsal interosseous and abductor pollicis brevis in non-dominant hands compared to dominant hands. Median nerve compound motor action potentials were significantly reduced in dominant compared to non-dominant hands. We conclude that the dominant hand is weaker than the non-dominant hand in patients with CMT1X.

Arthur-Farraj, P J

2012-07-01

291

Multiple microscopy modalities applied to a sea urchin tooth fragment.  

Science.gov (United States)

Two synchrotron X-ray microscopy methods, phase-contrast microradiography (the propagation method) and absorption microCT (high-resolution computed tomography or microtomography), and laser-scanning confocal microscopy (visible wavelength) were used to study a fragment of the keel of a tooth of the sea urchin Lytechinus variegatus. Stripes observed in the phase-contrast images of the fragment were also seen in confocal micrographs. MicroCT showed that the stripes were due to two parallel planar arrays of low-absorption channels within the bulk of the keel. In the phase microradiographs, maximum contrast stripes appear when a channel image from one row coincides with a channel image from the second row; otherwise, contrast is minimal. Long channels do not appear to have been observed previously in keels of sea urchin teeth. PMID:12944629

Stock, S R; Ignatiev, K; Dahl, T; Barss, J; Fezzaa, K; Veis, A; Lee, W K; De Carlo, F

2003-09-01

292

General tooth boundary conditions for equation free modelling  

CERN Document Server

We are developing a framework for multiscale computation which enables models at a ``microscopic'' level of description, for example Lattice Boltzmann, Monte Carlo or Molecular Dynamics simulators, to perform modelling tasks at ``macroscopic'' length scales of interest. The plan is to use the microscopic rules restricted to small "patches" of the domain, the "teeth'', using interpolation to bridge the "gaps". Here we explore general boundary conditions coupling the widely separated ``teeth'' of the microscopic simulation that achieve high order accuracy over the macroscale. We present the simplest case when the microscopic simulator is the quintessential example of a partial differential equation. We argue that classic high-order interpolation of the macroscopic field provides the correct forcing in whatever boundary condition is required by the microsimulator. Such interpolation leads to Tooth Boundary Conditions which achieve arbitrarily high-order consistency. The high-order consistency is demonstrated on ...

Roberts, A J

2006-01-01

293

Development of a Piezoelectric Ultrasonic Tooth-whitening Apparatus  

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Full Text Available The aim of this study was to develop an ultrasonic tooth-whitening apparatus using piezoelectric transducers,which enhance bleaching efficiency by applying ultrasound, while performing a teeth whitening procedure. For thispurpose, an ultrasonic transducer was designed and manufactured, and the effects of reduction in the whiteningmaterial’s concentration and in the whitening treatment time through using the ultrasound cavitation phenomenonwere confirmed. Also, the validity of this study was investigated by comparing the whitening performance with acommercialized optical whitener, through color comparison. The results revealed that the ultrasound whitenerproduced color values that were enhanced by as much as double that of the conventional LED light whiteningmethod. Even when the operational time was reduced by half, the ultrasound method showed superior performanceby over 54% compared to the conventional light whitener, revealing that the ultrasound method showed a remarkabletreatment reduction effect.

Young-Jin Lee

2013-10-01

294

The role of Irf6 in tooth epithelial invagination.  

Science.gov (United States)

Thickening and the subsequent invagination of the epithelium are an important initial step in ectodermal organ development. Ikk? has been shown to play a critical role in controlling epithelial growth, since Ikk? mutant mice show protrusions (evaginations) of incisor tooth, whisker and hair follicle epithelium rather than invagination. We show here that mutation of the Interferon regulatory factor (Irf) family, Irf6 also results in evagination of incisor epithelium. In common with Ikk? mutants, Irf6 mutant evagination occurs in a NF-?B-independent manner and shows the same molecular changes as those in Ikk? mutants. Irf6 thus also plays a critical role in regulating epithelial invagination. In addition, we also found that canonical Wnt signaling is upregulated in evaginated incisor epithelium of both Ikk? and Irf6 mutant embryos. PMID:22366192

Blackburn, James; Ohazama, Atsushi; Kawasaki, Katsushige; Otsuka-Tanaka, Yoko; Liu, Bigang; Honda, Kenya; Rountree, Ryan B; Hu, Yinling; Kawasaki, Maiko; Birchmeier, Walter; Schmidt-Ullrich, Ruth; Kinoshita, Akira; Schutte, Brian C; Hammond, Nigel L; Dixon, Michael J; Sharpe, Paul T

2012-05-01

295

Control of erosive tooth wear: possibilities and rationale  

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Full Text Available Dental erosion is a type of wear caused by non bacterial acids or chelation. There is evidence of a significant increase in the prevalence of dental wear in the deciduous and permanent teeth as a consequence of the frequent intake of acidic foods and drinks, or due to gastric acid which may reach the oral cavity following reflux or vomiting episodes. The presence of acids is a prerequisite for dental erosion, but the erosive wear is complex and depends on the interaction of biological, chemical and behavioral factors. Even though erosion may be defined or described as an isolated process, in clinical situations other wear phenomena are expected to occur concomitantly, such as abrasive wear (which occurs, e.g, due to tooth brushing or mastication. In order to control dental loss due to erosive wear it is crucial to take into account its multifactorial nature, which predisposes some individuals to the condition.

Mônica Campos Serra

2009-06-01

296

Ion microprobe U-Pb dating of a dinosaur tooth  

International Nuclear Information System (INIS)

Ion microprobe U-Pb dating of apatite is applied to a fossil tooth of a Allosaurid derived from the Hasandong Formation in the Gyeongsang basin, southeastern Korea. Twelve spots on a single fragment of the fossil dentine yield a Tera-Wasserburg concordia intercept age of 115±10 Ma (2?, MSWD=0.59) on a 238U/206Pb-207Pb/206Pb-204Pb/206Pb diagram. The age provides a constraint on the depositional age of the fossil in its host Hassandong Formation as Early Aptian. The success of the ion microprobe dating depends on the heterogeneities of diagenetically incorporated U and Pb at the few hundred ?m scale, the consequent variations in Pb isotopic compositions due to radioactive decay and the closed-system behavior of U and Pb. There are at least three end-members to explain the variations of minor chemical components such as FeO, SiO2 and Al2O3, and trace elements as Th, U and rare earth elements (REE) in the sample by a simple mixing model. They are (1) very low minor and REE, very high common Pb with variable U abundances, (2) low common Pb, high minor, REE, and U abundances, and (3) low minor, common Pb, and U with intermediate REE abundances, even though groups (2) and (3) may consist of a larger group. Various contributions of the three (and/or two) end-members during diagenetic processes may cause the elemental fractionation of U and Pb in a fossil tooth. (author)

297

Saw-tooth instability studies at the Stanford Linear Collider damping rings  

Science.gov (United States)

Saw-tooth instability occurs during high current operation in the Stanford Linear Collider (SLC) damping rings. This instability is single bunch and it can be cast as a longitudinal microwave instability. It is caused by the beam interaction with short range wakefields in the ring vacuum chamber. The saw-tooth instability manifests itself in the periodic blowup in quadrupole or higher moments in the longitudinal beam distribution. Most of our instability studies have been experimental. Since the measurements of coherent particle motion within a short ultrarelativistic beam are largely unconventional we had to develop some original diagnostics. These includes, for example, the down-conversion of the high frequency (10 GHz) broad-band beam position monitor (BPM) signals. We have also employed the state-of the art Hamamatsu streak camera that is capable of resolving the longitudinal beam distribution with sub-picosecond accuracy. As a result of our streak camera experiments we have quantitatively described the phase space of unstable bunches. We have found the radial structure of the instability mode and established that it only displaces a few percent of the beam particles. In another series of experiments we have correlated the instability signals from the beams before the extraction from the damping rings with their trajectories in the linac downstream. This showed that the instability results in a significant transverse beam jitter in the linac which compromises the damping ring performance as an injector. In addition, we have studied the instability behavior under the broad range of stored beam parameters using both passive and driven excitation. These measurements revealed unexpected beam behavior significantly above the instability threshold. Finally we performed several low current experiments to estimate the damping ring vacuum chamber impedance. We also present some analytical results regarding the instability and compare them to the observations. In particular, these include the explanation of unequal sidebands in the spectrum of the BPM signal coming from unstable bunches. In addition we have obtained several results regarding the instability onset criteria and proposed a new method of estimating the instability threshold based on the steady-state solution of the Fokker-Planck equation.

Podobedov, Boris Vyacheslavovich

2000-08-01

298

Evaluation of the force applied by the tongue and lip on the maxillary central incisor tooth  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english PURPOSE: To describe the development and testing of a system that measures forces exerted by the tongue and upper lip on a tooth during rest and during swallowing. METHODS: Twenty-eight subjects, aged 19-31 years (mean: 23.2 years) were submitted to measurement of forces exerted by the upper l [...] ip and tongue on the maxillary right central incisor tooth. Flexiforce resistive sensors were fixed on the labial and lingual surfaces of the tooth. They were connected to an amplifier circuit and a data acquisition board for processing and transmitting information to a computer. RESULTS: At rest, the tongue force on the tooth was 0.00±0.00 N and the lip force on tooth was 0.02±0.02 N. The difference between them was significant. During swallowing, the values were 0.31±0.38 N and 0.15±0.14 N, for the tongue and lip, respectively. This difference was not significant. CONCLUSION: At rest, the lip exerts a larger force than the tongue on the maxillary right central incisor tooth. During swallowing, there was no difference between lip and tongue force on the tooth.

Amanda Freitas, Valentim; Renata Maria Moreira Moraes, Furlan; Tatiana Vargas de Castro, Perilo; Monalise Costa Batista, Berbert; Andréa Rodrigues, Motta; Estevam Barbosa de Las, Casas.

2014-06-01

299

Expression of cytokeratin 8, vimentin, syndecan-1 and Ki-67 during human tooth development.  

Science.gov (United States)

Spatio-temporal immunolocalizations of cytokeratin 8 (CK8), vimentin, syndecan-1 and Ki-67 were analyzed in ten human incisors and canine tooth germs between the 7th and 20th developmental weeks. CK8 expression was mild to moderate in the epithelial tooth parts, while it shifted from absent or mild in its mesenchymal parts, but few cells, sparsely distributed throughout the tooth germ, strongly expressed CK8. As development progressed, CK8 expression increased to strong in preameloblasts, while expression of vimentin increased to moderate in the epithelial and mesenchymal tooth parts, particularly in the dental papilla and sac. Co-expression of CK8 and vimentin was observed in some parts of the tooth germ, and was increasing in the differentiating preameloblasts and preodontoblasts. Syndecan-1 showed characteristic shift of expression from epithelial to mesenchymal tooth parts, being particularly strong in dental papilla, sac and cervical loops, while co-expression of Ki-67/syndecan-1 was strong in the dental papilla. Our study demonstrated spatio-temporal expression and restricted co-expression of the investigated markers, indicating participation of CK8 and vimentin in cell proliferation and migration, and differentiation of preodontoblasts and preameloblasts. Our data also suggest involvement of syndecan-1 in morphogenesis of the developing tooth crown and cervical loops, and together with CK8 and vimentin in differentiation of preameloblasts and preodontoblasts. PMID:25120060

Kero, D; Kalibovic Govorko, D; Vukojevic, K; Cubela, M; Soljic, V; Saraga-Babic, M

2014-12-01

300

Evaluation of prevalence and etiologic factors of tooth discoloration in male high school students in Isfahan  

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Full Text Available AbstractIntroduction: Knowledge of prevalence and etiologic factors of tooth discoloration can help design strategies for intervention to prevent tooth discoloration. The aim of this study was to determine the prevalence and etiologic factors of tooth discoloration in male high school students in Isfahan.Materials and methods: In this cross-sectional study, 384 male students were selected by cluster sampling method. The students were examined by a well-instructed individual. Data was collected and recorded using a questionnaire and then analyzed by descriptive methods in SPSS at a 95% confidence interval.Results: The prevalence of tooth discoloration was 89.9% in male high school students in Isfahan. Relative frequencies of etiologic factors of tooth discoloration consisted of caries, 80.6%; hypoplasia, 18.2%; extrinsic stains, 9.5%; root and crown restorative materials, 4.8%; trauma, 1.3%; tetracycline and smoking, 0.8%; fluorosis, 0.5%; and chlorhexidine mouthwash, 0.3%. No cases of amelogenesis imperfecta, dentinogenesis imperfecta, and drug use by mothers during pregnancy. Conclusion: In this study caries was the most common cause of tooth discoloration. Given the high prevalence of carious lesions, instruction of oral hygiene habits and improving nutrition of the students are recommended. Key words: Etiologic factors, frequency, male students, Tooth discoloration.

Parichehr Ghalyani

2012-01-01

 
 
 
 
301

The timing of tooth eruption and root development of permanent canine and premolars in Korean children  

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The aim of this study was to investigate the timing and sequence of eruption of permanent canine and premolars, and to evaluate tooth calcification stage on emergence in Korean children. The sample was comprised of 1,266 children (male 720, female 546) aged from 7-13 years. Tooth eruption and calcification stages were determined through oral and panoramic radiographic examination, respectively. Probit analysis was used to calculate the timing of tooth eruption and tooth calcification stage from these cross-sectional data. In both males and females, eruption occurred around the time when one third of tooth root or more was formed. The sequence was as follows: first premolar, canine, and second premolar in maxilla, and canine, first premolar and second premolar in mandible. Tooth eruption occurred earlier in girls compared with boys, averaging 0.63 years. Eruption sequence is identical in males and females with a trend for females to erupt earlier than males. Tooth eruption becomes earlier over the past decades in Korean children.

Cheong, Chang Shin; Jung, Yun Hoa; Cho, Bong Hae [Department of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Pusan (Korea, Republic of)

2010-09-15

302

The timing of tooth eruption and root development of permanent canine and premolars in Korean children  

International Nuclear Information System (INIS)

The aim of this study was to investigate the timing and sequence of eruption of permanent canine and premolars, and to evaluate tooth calcification stage on emergence in Korean children. The sample was comprised of 1,266 children (male 720, female 546) aged from 7-13 years. Tooth eruption and calcification stages were determined through oral and panoramic radiographic examination, respectively. Probit analysis was used to calculate the timing of tooth eruption and tooth calcification stage from these cross-sectional data. In both males and females, eruption occurred around the time when one third of tooth root or more was formed. The sequence was as follows: first premolar, canine, and second premolar in maxilla, and canine, first premolar and second premolar in mandible. Tooth eruption occurred earlier in girls compared with boys, averaging 0.63 years. Eruption sequence is identical in males and females with a trend for females to erupt earlier than males. Tooth eruption becomes earlier over the past decades in Korean children.

303

Analysis of tooth decay data in Japan using asymmetric statistical models  

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Full Text Available Kouji Yamamoto,1 Sadao Tomizawa21Department of Medical Innovation, Osaka University Hospital, Osaka, 2Department of Information Sciences, Faculty of Science and Technology, Tokyo University of Science, Noda City, Chiba, JapanBackground: The aim of the present paper was to develop two new asymmetry probability models to analyze data for tooth decay from 363 women and 349 men aged 18–39 years who visited a dental clinic in Sapporo City, Japan, from 2001 to 2005.Methods: We analyzed the probability relationship between grade of upper and lower tooth decay for men and women using the two new models, and tested goodness-of-fit for the models.Results: The probability that a woman's (man's grade of lower tooth decay is i (i = 1,2 and her (his grade of upper tooth decay is j(>i, (j = 2,3 is estimated to be at most 13.52 (10.23 times higher than the probability that the woman's (man's grade of upper tooth decay is i and grade of lower tooth decay is j.Conclusion: From the data on tooth decay, decay of the upper teeth is worse than of the lower teeth in women and men, and the tendency becomes stronger as the numbers of decayed upper and lower teeth increase.Keywords: distance-proportional symmetry, asymmetry, square contingency table, teeth

Tomizawa S

2012-11-01

304

Differential diagnosis of spall vs. cracks in the gear tooth fillet region: Experimental validation  

Science.gov (United States)

This paper presents a technique to differentially diagnose two types of localized gear tooth faults: a spall and a crack in the gear tooth fillet region. These faults could have very different prognoses, but existing diagnostic techniques only detect the presence of localized tooth faults without being able to differentiate between a spall and a crack. The effects of spalls and cracks on the behaviour of gear assemblies were studied using static and dynamic simulation models. Changes in the kinematics of a pair of meshing gears due to a gear tooth fillet crack (TFC) and a tooth flank spall were compared using a static analysis model. The difference in the variation of the transmission error (TE) caused by the two faults reveals their characteristics. The effect of a tooth crack depends on the change in stiffness of the tooth while the effect of a spall is dominantly determined by the geometry of the fault. A technique has previously been proposed to detect spalls [M. EL Badaoui, J. Antoni, F. Guillet, J. Daniere, Use of the moving cepstrum integral to detect and localize tooth spalls in gears, Mechanical System and Signal Processing, 15 (5) (2001) 873-885; M. EL Badaoui, V. Cahouet, F. Guillet, J. Daniere P. Velex, Modelling and detection of localized tooth defects in geared systems, Transaction of ASME, 123 (2001) 422-430], using the cepstrum to detect a negative echo in the signal (from entry into and exit from the spall) and successfully performed differential diagnosis on the simulated vibration signals. While the result of the experimental study showed some differences from the result of the simulation study, the differential diagnosis was successfully performed based on the technique presented in this paper. Further investigation revealed non-linear gearmesh behaviour which was causing differences in the experimental and simulation model results.

Endo, H.; Randall, R. B.; Gosselin, C.

2009-04-01

305

The effect of cigarette smoking on the healing of extraction sockets: an immunohistochemical study.  

Science.gov (United States)

The aim of this study was to investigate immunohistochemically the influence of cigarette smoking on the socket healing after tooth extraction in rats. Eighty-four male rats were divided into 3 groups; 2 groups were considered as experimental and the other as control. The animals in test 1 were exposed to smoking regimen before the surgery and after the surgery, but the animals in test 2 were exposed to the smoking regimen only before surgery. All animals' maxillary right central incisors were extracted and killed at the 3rd, 7th, 15th, and 28th day. The samples taken on third day after tooth extraction were stained immunohistochemically with fibronectin antibody and the other with type I collagen antibody. On the third day after tooth extraction, samples in the control group were intense stained (3) (+++); in the test 1 they were slight positive (1) (+) and in the test 2 they were moderate positive (2) (+ +). As a result of scoring type I collagen antibody, there was no statistically significant difference between the groups at seventh day, but there were statistically significant differences between the groups at the 15th and 28th day (P = 0.000 and P = 0.001, respectively). Comparison of the paired intense scores of type I collagen antibody staining according to days within each groups were not statistically significant. As a result, we have found out that the healing process of the tooth extraction socket is negatively affected by cigarette smoke. PMID:24481166

Ozkan, Aydin; Bayar, Gurkan Rasit; Altug, Hasan Ayberk; Sencimen, Metin; Dogan, Necdet; Gunaydin, Yilmaz

2014-07-01

306

Tobacco use and incidence of tooth loss among US male health professionals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Data on the dose dependent effect of smoking and smoking cessation on tooth loss are scarce. We hypothesized that smoking has a dose and time dependent effect on tooth loss incidence. We used longitudinal data on tobacco use and incident tooth loss in 43,112 male health professionals between 1986 and 2002. In multivariate Cox models, current smokers of 5 to 14 and 45+ cigarettes daily had a two-fold (HR: 1.94; 95% CI: 1.72, 2.18) and three-fold (HR: 3.05; 95% CI: 2.38, 3.90) higher risk of to...

Dietrich, T.; Maserejian, N. N.; Joshipura, K. J.; Krall, E. A.; Garcia, R. I.

2007-01-01

307

Dependencies of the radiation sensitivity of human tooth enamel in EPR dosimetry  

International Nuclear Information System (INIS)

The EPR dose response of tooth enamel was determined for human molars collected in Egypt. The influence of age, gender and residence of the tooth donors as well as tooth position and sample preparation on EPR sensitivity and its variability over the enamel samples was investigated. The EPR sensitivity and its variability were found to depend only on the sample preparation procedure. The variability in EPR sensitivity of enamel from Egyptian teeth was maximally 10% and the mean sensitivity was in good agreement with that of German teeth

308

Charcot Marie Tooth Disease Type 1 - Rare but Commonest Hereditary Neuropathy  

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Full Text Available Objective: To present a case of Charcot Marie Tooth Disease. Backgrounds: A 22 years old boy presented with very slowly progressive symmetrical weakness of both lower limbs with distal muscular atrophy. He has a family member with similar problem. Methods: The patient was clinically examined and investigations done accordingly like Nerve Conduction Velocity studies (NCV. Results: The patient was diagnosed to be a case of Charcot Marie Tooth disease type 1 with classical features like” inverted Champagne bottle” like legs. Conclusion: Charcot Marie Tooth disease is rare and often undiagnosed yet it is the commonest hereditary neuropathy worldwide and India is not an exception

Shakya Bhattacharjee

2012-01-01

309

The Fixation Technique of Artificial Crowns with Preliminary Preventive Treatment of Tooth Stump  

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Full Text Available The article gives the recommendations for artificial crowns cementing using prophylactic drugs aimed at the prevention of complex cavity of hard tissues of a prepared tooth. Preliminary use of prophylactic drug before final fixation of artificial crowns contributes to deep fluorization of hard tooth tissues, and thus, provides long stable positioning of dentures on prepared hard tissues of natural teeth. Clinical trials carried out showed that along with a precisely poured denture and try-in, the technique provides high caries-resistant of hard tooth tissues under an artificial crown.

?.N. Zhulev

2012-08-01

310

Experimental procedure for the evaluation of tooth stiffness in spline coupling including angular misalignment  

Science.gov (United States)

Tooth stiffness is a very important parameter in studying both static and dynamic behaviour of spline couplings and gears. Many works concerning tooth stiffness calculation are available in the literature, but experimental results are very rare, above all considering spline couplings. In this work experimental values of spline coupling tooth stiffness have been obtained by means of a special hexapod measuring device. Experimental results have been compared with the corresponding theoretical and numerical ones. Also the effect of angular misalignments between hub and shaft has been investigated in the experimental planning.

Curà, Francesca; Mura, Andrea

2013-11-01

311

Providing support for the pontic of natural tooth adhesive bridges: a clinical report.  

Science.gov (United States)

Resin bonded bridges have become established as a treatment option for replacing missing teeth. Their development can be traced to the work of Rochette who used a macro mechanically bonded metal framework to stabilize mobile teeth. Adaptations of Rochette's concept, using natural teeth as pontics, have been presented. The use of a natural tooth has aesthetic and psychological advantages for the patient. The high failure rate of natural tooth pontics may be explained by a lack of support for the tooth on the metal framework. A clinical report is presented to illustrate a previously unreported technique to improve pontic support. PMID:21077422

Al-Diwani, Hiba; Hyde, T Paul; Gregory, Paul; Brunton, Paul

2010-09-01

312

Unilateral Fusion of a Mandibular Third Molar to a Supernumerary Tooth: A Case Report  

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Full Text Available Fusion is a developmental anomaly defined as the union of two normally separated tooth buds or the partial splitting of one tooth bud into two buds. Depending on the stage of development, fusion may be either complete or incomplete.The significance of this particular case was that this fusion occurred in a posterior permanent mandibular tooth, while such a manifestation is more reported in maxillary anterior teeth; either in the primary (0.5% or permanent (0.1% dentition.The genetic basis for this anomaly is probably autosomal dominant with reduced penetrance. In addition, the essential findings for differential diagnosis include numberof teeth, radiography and clinical features.

JB Taheri

2005-03-01

313

Filling of extraction sockets of feline maxillary canine teeth with autogenous bone or bioactive glass  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english PURPOSE: To evaluate bone healing in the extraction socket of the feline maxillary canine tooth after grafting. METHODS: Eighteen adult cats were submitted to unilateral extraction of maxillary canine tooth and divided into three groups. In group 1 (n=6), control, the extraction socket was left empt [...] y. In group 2 (n=6), the extraction socket was filled with autogenous cancellous bone from the iliac crest and in group 3 (n=6), with bioactive glass particulate material. Cats were euthanized at four weeks postoperative. RESULTS: The radiographic examinations performed four weeks after surgery showed that in all groups the healing process converged to a radiopacity similar to that observed in the surrounding bones. Histological examination showed formation of woven bone within the extraction socket. The percentage of newly formed bone within the extraction socket, measured by the histometry, showed no statistically significant difference among the values of the three groups (Kruskal-Wallis'test p>0.05) (group 1: 63.96 ± 5.85, group 2: 66.84 ± 11.67, group 3: 59.28 ± 15.50). CONCLUSION: The bone regeneration observed in the extraction sockets filled with autogenous cancellous bone or bioactive glass was similar to that observed in the control sites, given an observation period of four weeks after extraction of the maxillary canine tooth.

Adelina Maria da, Silva; Rafael Dias, Astolphi; Sílvia Helena Venturoli, Perri; Marion Burkhardt de, Koivisto.

314

Filling of extraction sockets of feline maxillary canine teeth with autogenous bone or bioactive glass  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english PURPOSE: To evaluate bone healing in the extraction socket of the feline maxillary canine tooth after grafting. METHODS: Eighteen adult cats were submitted to unilateral extraction of maxillary canine tooth and divided into three groups. In group 1 (n=6), control, the extraction socket was left empt [...] y. In group 2 (n=6), the extraction socket was filled with autogenous cancellous bone from the iliac crest and in group 3 (n=6), with bioactive glass particulate material. Cats were euthanized at four weeks postoperative. RESULTS: The radiographic examinations performed four weeks after surgery showed that in all groups the healing process converged to a radiopacity similar to that observed in the surrounding bones. Histological examination showed formation of woven bone within the extraction socket. The percentage of newly formed bone within the extraction socket, measured by the histometry, showed no statistically significant difference among the values of the three groups (Kruskal-Wallis'test p>0.05) (group 1: 63.96 ± 5.85, group 2: 66.84 ± 11.67, group 3: 59.28 ± 15.50). CONCLUSION: The bone regeneration observed in the extraction sockets filled with autogenous cancellous bone or bioactive glass was similar to that observed in the control sites, given an observation period of four weeks after extraction of the maxillary canine tooth.

Adelina Maria da, Silva; Rafael Dias, Astolphi; Sílvia Helena Venturoli, Perri; Marion Burkhardt de, Koivisto.

2013-12-01

315

Molecular evolution of dentin phosphoprotein among toothed and toothless animals  

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Full Text Available Abstract Background Dentin sialophosphoprotein (DSPP is the largest member of the SIBLING family and is the most abundant noncollagenous protein in dentin. DSPP is also expressed in non-mineralized tissues including metabolically active ductal epithelia and some cancers. Its function, however, is poorly defined. The carboxy-terminal fragment, dentin phosphoprotein (DPP is encoded predominantly by a large repetitive domain that requires separate cloning/sequencing reactions and is, therefore, often incomplete in genomic databases. Comparison of DPP sequences from at least one member of each major branch in the mammalian evolutionary tree (including some "toothless" mammals as well as one reptile and bird may help delineate its possible functions in both dentin and ductal epithelia. Results The BMP1-cleavage and translation-termination domains were sufficiently conserved to permit amplification/cloning/sequencing of most species' DPP. While the integrin-binding domain, RGD, was present in about half of species, only vestigial remnants of this tripeptide were identified in the others. The number of tandem repeats of the nominal SerSerAsp phosphorylation motif in toothed mammals (including baleen whale and platypus which lack teeth as adults, ranged from ~75 (elephant to >230 (human. These repeats were not perfect, however, and patterns of intervening sequences highlight the rapidity of changes among even closely related species. Two toothless anteater species have evolved different sets of nonsense mutations shortly after their BMP1 motifs suggesting that while cleavage may be important for DSPP processing in other tissues, the DPP domain itself may be required only in dentin. The lizard DSPP had an intact BMP1 site, a remnant RGD motif, as well as a distinctly different Ser/Asp-rich domain compared to mammals. Conclusions The DPP domain of DSPP was found to change dramatically within mammals and was lost in two truly toothless animals. The defining aspect of DPP, the long repeating phosphorylation domain, apparently undergoes frequent slip replication and recombination events that rapidly change specific patterns but not its overall biochemical character in toothed animals. Species may have to co-evolve protein processing mechanisms, however, to handle increased lengths of DSP repeats. While the RGD domain is lost in many species, some evolutionary pressure to maintain integrin binding can be observed.

Fisher Larry W

2009-12-01

316

Saw-tooth oscillations of soft X radiation in the L-2 stellarator  

International Nuclear Information System (INIS)

Results of the experimental investigation of saw-tooth oscillations in the L-2 stellarator plasma under the mode of the Joule heating are presented. The dependences of oscillation period, amplitude of saw-tooth modulation and radius of resonance surface on the discharge parameters: average electron density and current value of the Joule heating are stated. It is shown that the effect on plasma conductivity produced by electrons locked on the crimps of spiral winding of the stellarator results in formation of sharpened profile of current density at which occurrence of relaxation oscillations is possible. It is stated that energy losses from the central region of plasma caused by saw-tooth oscillations make up approximately 50% of the power of the Joule heating released in this region. Presence of saw-tooth oscillations in the discharge permits to carry out upper evaluation of the effective plasma charge wchich gives the value 3-4

317

Gender differences in tooth loss among Chilean adolescents: socio-economic and behavioral correlates  

DEFF Research Database (Denmark)

OBJECTIVE: To investigate gender differences in tooth loss among Chilean adolescents and its association with selected socio-economic indicators and oral-health-related behaviors. MATERIAL AND METHODS: Data on 9,163 Chilean adolescents obtained using multistage random cluster procedures. Clinical recordings included information on missing teeth and the participants provided information on socio-demographic factors and oral-related behaviors. Two eruption-time-adjusted logistic regression analyses were used to investigate the associations between gender, tooth loss and socio-economic position/oral-health-related behaviors. RESULTS: The association between gender and tooth loss remained after adjusting for age, eruption times in both the socio-economic position regression model and the oral-health-related behaviors model. Tooth loss followed social gradients for the variables paternal income and achieved parental education, with students reporting a paternal income

López, Rodrigo; Baelum, Vibeke

2006-01-01

318

Changes of masticatory movement characteristics after prosthodontic rehabilitation of individuals with extensive tooth wear.  

Science.gov (United States)

The masticatory cycles of 11 men (mean age 51.5 years) with extensive tooth wear were investigated before and after rehabilitation with fixed partial dentures. Parameters such as the tooth wear index (IA) and masticatory mandibular movement were recorded. Before treatment, the patients were also given a questionnaire related to possible background factors of importance to tooth wear. At baseline a mean score of 48.6 (range 0 to 100) for the tooth wear index (IA) was found. The clinical recall examination 3 years after prosthodontic rehabilitation displayed obvious wear of restorative material for two patients, and, in another patient, one of the fixed partial dentures had to be remade because of fracture of abutment teeth. Following rehabilitation, the duration of the masticatory mandibular opening movement increased and mandibular movement velocity decreased. The mandibular closing angle, near to occlusal contact, became steeper after prosthodontic treatment, indicating a changed mandibular movement pattern. PMID:9171492

Ekfeldt, A; Karlsson, S

1996-01-01

319

21 CFR 872.3910 - Backing and facing for an artificial tooth.  

Science.gov (United States)

...false Backing and facing for an artificial tooth. 872.3910 Section 872.3910 Food and Drugs FOOD AND DRUG ADMINISTRATION...MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3910 Backing and facing for an artificial...

2010-04-01

320

Computerized Modeling and Loaded Tooth Contact Analysis of Hypoid Gears Manufactured by Face Hobbing Process  

Science.gov (United States)

The face hobbing process has been widely applied in automotive industry. But so far few analytical tools have been developed. This makes it difficult for us to optimize gear design. To settle this situation, this study aims at developing a computerized tool to predict the running performances such as loaded tooth contact pattern, static transmission error and so on. First, based upon kinematical analysis of a cutting machine, a mathematical description of tooth surface generation is given. Second, based upon the theory of gearing and differential geometry, conjugate tooth surfaces are studied. Then contact lines are generated. Third, load distribution along contact lines is formulated. Last, the numerical model is validated by measuring loaded transmission error and loaded tooth contact pattern.

Nishino, Takayuki

 
 
 
 
321

THE EFFECTS OF PGE1 AND INDOMETHACIN ON ORTHODONTIC TOOTH MOVEMENT IN RAT  

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Full Text Available  Prostaglandin £j (PGE-^ and indomethacin, a nonstroidal antiinflammatory drug, were separately administered during ortliodontic tooth movement in rats. At the beginning, an orthodontic appliance was placed and activated in male albinos rats. In tlie first examination, the experimental group received submucosal injections of PGE-y (10 mg/kg/day near the first maxillary riglit molars, and alcohol was injected to control group animals as a vehicle similarly. Jn the second examination, indomethacin (10 mg/kg/day and metiiyl cellulose subcutaneousfy injected to experimental and control groups respectively. Tooth movement was measured at 1,3,5,7,9 and 11 days. In PGE^ group, tooth movement increased significantly at the beginning of seven days as compared to the vehicle injected group and the number of osteoclast and Howship's lacunae were markedly increased. A significant iniiibition of tooth movement occurred beginning at seven days in the indomethacin group compared to the control group.

EA. Niaki

1999-09-01

322

Cigarette smoking and tooth loss experience among young adults: a national record linkage study  

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Full Text Available Abstract Background Various factors affect tooth loss in older age including cigarette smoking; however, evidence regarding the association between smoking and tooth loss during young adulthood is limited. The present study examined the association between cigarette smoking and tooth loss experience among adults aged 20–39 years using linked data from two national databases in Japan. Methods Two databases of the National Nutrition Survey (NNS and the Survey of Dental Diseases (SDD, which were conducted in 1999, were obtained from the Ministry of Health, Labor and Welfare with permission for analytical use. In the NNS, participants received physical examinations and were interviewed regarding dietary intake and health practices including cigarette smoking, whereas in the SDD, participants were asked about their frequency of daily brushing, and received oral examinations by certified dentists. Among 6,805 records electronically linked via household identification code, 1314 records of individuals aged 20 to 39 years were analyzed. The prevalence of 1+ tooth loss was compared among non-, former, and current smokers. Multiple logistic regression models were constructed including confounders: frequency of tooth brushing, body mass index, alcohol consumption, and intake of vitamins C and E. Results Smoking rates differed greatly in men (53.3% and women (15.5%. The overall prevalence of tooth loss was 31.4% (31.8% men and 31.1% women. Tooth loss occurred more frequently among current smokers (40.6% than former (23.1% and non-smokers (27.9%. Current smoking showed a significant association with 1+ tooth loss in men (adjusted OR = 2.21 [1.40–3.50], P = 0.0007 and women (1.70 [1.13–2.55], P = 0.0111. A significant positive exposure-related relationship between cigarette smoking status and tooth loss was observed (P for trend Conclusion An association between cigarette smoking and tooth loss was evident among young adults throughout Japan. Due to limitations of the available variables in the present databases, further studies including caries experience and its confounders should be conducted to examine whether smoking is a true risk of premature tooth loss in young adults.

Tanaka Keiko

2007-11-01

323

Severe tooth wear in Prader-Willi syndrome. A case–control study  

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Full Text Available Abstract Background Prader-Willi syndrome (PWS is a rare complex multsystemic genetic disorder characterized by severe neonatal hypotonia, endocrine disturbances, hyperphagia and obesity, mild mental retardation, learning disabilities, facial dysmorphology and oral abnormalities. The purpose of the present study was to explore the prevalence of tooth wear and possible risk factors in individuals with Prader-Willi syndrome. Methods Forty-nine individuals (6-40?years with PWS and an age- and sex-matched control group were included. Tooth wear was evaluated from dental casts and intraoral photographs and rated by four examiners using the Visual Erosion Dental Examination (VEDE scoring system and the individual tooth wear index IA. In accordance with the VEDE scoring system, tooth wear was also evaluated clinically. Whole saliva was collected. Results Mean VEDE score was 1.70?±?1.44 in the PWS group and 0.46?±?0.36 in the control group (p?A was 7.50 (2.60-30.70 in the PWS group and 2.60 (0.90-4.70 among controls (p?A; r?=?0.82, p?A; r?=?0.43, p?=?0.002. Tooth grinding was also associated with tooth wear in the PWS group, as indicated by the mean VEDE 2.67?±?1.62 in grinders and 1.14?±?0.97 in non-grinders (p?=?0.001 and median IA values 25.70 (5.48-68.55 in grinders and 5.70 (1.60-9.10 in non-grinders (p?=?0.003. Multivariate linear regression analysis was performed with tooth wear as the dependent variable and PWS (yes/no, age, tooth grinding and saliva secretion as independent variables. PWS (yes/no, age and tooth grinding retained a significant association with tooth wear, VEDE (p?A (p? Conclusions Our study provides evidence that tooth wear, in terms of both erosion and attrition, is a severe problem in Prader-Willi syndrome. There is therefore considerable need for prosthodontic rehabilitation in young adults with PWS.

Saeves Ronnaug

2012-05-01

324

Intrusion in implant-tooth-supported fixed prosthesis: An in vitro photoelastic stress analysis  

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Full Text Available Background and Objective: Intrusion of natural teeth is a very common and interesting problem associated with implant-assisted fixed partial prostheses. Various theories have been put forth to explain this phenomenon, most of which revolve around the philosophy of exertion of excessive forces onto the natural tooth in a combination fixed partial denture. This photoelastic study examines the current theories revolving around intrusion and evaluates whether natural tooth intrusion is a definite possibility in an implant-tooth-connected fixed partial prosthesis. Materials and Methods: A two-dimensional photoelastic method was employed for testing and analysis. Two sets of photoelastic models were fabricated, one depicting a totally tooth-supported situation and the other an implant-tooth-supported situation. A rigid type and non-rigid type of connection were also incorporated into the fixed partial denture used in the both the situations in the study. Loads were applied on the anterior and posterior abutments and the pontic regions in both sets of models and the fringe patterns were photographically recorded for analysis. Results and Conclusion: The forces were proportionately consistent with the increase in applied loads in both the situations. The use of a non-rigid connection did not show any major significance but in fact may be erroneous. The forces were considerably higher in the implant-tooth-connected situation. The results indicated that the differences in the forces exerted were not light and continuous and may not cause tooth intrusion. Natural tooth intrusion may be caused by reasons other than excessive forces and needs further investigation.

Srinivasan Murali

2008-01-01

325

Effect of repeated immersion solution cycles on the color stability of denture tooth acrylic resins  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english OBJECTIVE: Chemical solutions have been widely used for disinfection of dentures, but their effect on color stability of denture tooth acrylic resins after repeated procedures is still unclear. The aim of this in vitro study was to evaluate whether repeated cycles of chemical disinfectants affected [...] the color stability of two denture tooth acrylic resins. MATERIAL AND METHODS: Sixty disc-shaped specimens (40 mm x 3 mm) were fabricated from two different brands (Artiplus and Trilux) of denture tooth acrylic resin. The specimens from each brand (n=30) were randomly divided into 6 groups (n=5) and immersed in the following solutions: distilled water (control group) and 5 disinfecting solutions (1% sodium hypochlorite, 2% sodium hypochlorite, 5.25% sodium hypochlorite, 2% glutaraldehyde, and 4% chlorhexidine gluconate). Tooth color measurements were made by spectrophotometry. Before disinfection, the initial color of each tooth was recorded. Further color measurements were determined after subjecting the specimens to 7, 21, 30, 45, 60, and 90 immersion cycles in each tested solution. Color differences (?E*) were determined using the CIE L*a*b* color system. Data were analyzed using two-way repeated measures analysis of variance (ANOVA) followed by Tukey tests. The significance level was set at 5%. RESULTS: There were statistically significant differences in ?E* among the 5 disinfectants and water during the 90 cycles of immersion for both denture tooth acrylic resins. Distilled water promoted the greatest color change in both denture tooth acrylic resins, nevertheless none of tested disinfectants promoted ?E* values higher than 1.0 on these acrylic materials during the 90 cycles of disinfection. CONCLUSIONS: Repeated immersion cycles in disinfecting solutions alter ?E* values, however these values do not compromise the color of the tested denture tooth acrylic resins because they are imperceptible to the human eye.

Paulo Maurício Batista da, Silva; Emílio José Tabaré Rodríguez, Acosta; Matheus, Jacobina; Luciana de Rezende, Pinto; Vinícius Carvalho, Porto.

326

Natural selection and molecular evolution in primate PAX9 gene, a major determinant of tooth development  

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Large differences in relation to dental size, number, and morphology among and within modern human populations and between modern humans and other primate species have been observed. Molecular studies have demonstrated that tooth development is under strict genetic control, but, the genetic basis of primate tooth variation remains unknown. The PAX9 gene, which codes for a paired domain-containing transcription factor that plays an essential role in the development of mammal dentition, has bee...

Pereira, Tiago V.; Salzano, Francisco M.; Mostowska, Adrianna; Trzeciak, Wieslaw H.; Ruiz-linares, Andre?s; Chies, Jose? A. B.; Saavedra, Carmen; Nagamachi, Cleusa; Hurtado, Ana M.; Hill, Kim; Castro-de-guerra, Dinorah; Silva-ju?nior, Wilson A.; Bortolini, Maria-ca?tira

2006-01-01

327

Effect of repeated immersion solution cycles on the color stability of denture tooth acrylic resins  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVE: Chemical solutions have been widely used for disinfection of dentures, but their effect on color stability of denture tooth acrylic resins after repeated procedures is still unclear. The aim of this in vitro study was to evaluate whether repeated cycles of chemical disinfectants affected the color stability of two denture tooth acrylic resins. MATERIAL AND METHODS: Sixty disc-shaped specimens (40 mm x 3 mm were fabricated from two different brands (Artiplus and Trilux of denture tooth acrylic resin. The specimens from each brand (n=30 were randomly divided into 6 groups (n=5 and immersed in the following solutions: distilled water (control group and 5 disinfecting solutions (1% sodium hypochlorite, 2% sodium hypochlorite, 5.25% sodium hypochlorite, 2% glutaraldehyde, and 4% chlorhexidine gluconate. Tooth color measurements were made by spectrophotometry. Before disinfection, the initial color of each tooth was recorded. Further color measurements were determined after subjecting the specimens to 7, 21, 30, 45, 60, and 90 immersion cycles in each tested solution. Color differences (?E* were determined using the CIE L*a*b* color system. Data were analyzed using two-way repeated measures analysis of variance (ANOVA followed by Tukey tests. The significance level was set at 5%. RESULTS: There were statistically significant differences in ?E* among the 5 disinfectants and water during the 90 cycles of immersion for both denture tooth acrylic resins. Distilled water promoted the greatest color change in both denture tooth acrylic resins, nevertheless none of tested disinfectants promoted ?E* values higher than 1.0 on these acrylic materials during the 90 cycles of disinfection. CONCLUSIONS: Repeated immersion cycles in disinfecting solutions alter ?E* values, however these values do not compromise the color of the tested denture tooth acrylic resins because they are imperceptible to the human eye.

Paulo Maurício Batista da Silva

2011-12-01

328

X-linked Charcot-Marie-Tooth disease with myokymia: Report of a family  

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Full Text Available The clinical and electrophysiologic profiles of two brothers suffering from Charcot-Marie-Tooth disease are presented. Both had widespread muscle twitching in the legs which showed electrophysiologic features of myokymia. Pedigree analysis suggested an x-linked recessive form of inheritance. This appears to be the first report of an Indian family with x-linked Charcot-Marie-Tooth disease.

Chakravarty A

2003-07-01

329

Tooth apatite as a bone substitute: an experimental study and clinical applications  

International Nuclear Information System (INIS)

The purpose of this study is to evaluate the usefulness of calcined teeth powder as biological apatite. The animal experiment was performed in 36 rabbits aging 6 weeks and weighing 1.6 kg. In experimental group, tooth apatite powder was implanted to 10 mm bony defects in diameter made on the cranial bone of the rabbits. As control groups, synthetic porous hydroxyapatite and resorbable type calcium carbonate were implanted to the defects of same size. Each group was sacrificed in 1, 2, 4, 6, 8, 12 weeks after the surgery. Specimens were prepared for decalcified samples and observed by a light microscope. And we also performed quantitative analysis of new bone formation through image analysis using computer. In clinical applications, we used tooth apatite alone or mixed with decalcified freeze-dried bone for reconstruction of bony defects in 15 patients undergone enucleation of cyst or ameloblastoma. The obtained results were as follows; 1) The powder of the calcined teeth was called as 'tooth apatite' and it seemed to have biocompatibility in rabbits and human. 2) In group of tooth apatite, after 4 weeks of operation, new bone directly bonded to the particles was observed. And in 12 weeks of it, new bone occupied most of the bony defects. In 6 weeks, resorption of the tooth apatite particles was observed. Thus the tooth apatite was regarded as one of resorbable apatite. 3) The group of tooth apatite showed new bone formation similar to the group of porous hydroxyapatitmilar to the group of porous hydroxyapatite, but they were inferior to the group of resorbable calcium carbonate. 4) In clinical application, tooth apatite had biocompatibility and new bone formation was observed without any complication except for 1 case. So we think it is a useful bone substitute with osteoconductivity

330

Visualization of x-ray microtomography data for a human tooth atlas  

Science.gov (United States)

Three-dimensional x-ray microtomography is used in this work to assess the internal morphology and mineral density of human tooth specimens. Of particular interest is the demonstration of the character of the distal root canal morphology, which can be as small as 10 microns. Human teeth are individually embedded in a low atomic number material. Each tooth is then identically scanned on an advanced design bench-top cone-beam microtomography system under controlled conditions. The specimens are scanned using an 80 kVp technique and a CsI(Tl) scintillator mounted via a taper to a thermoelectrically cooled CCD camera with an overall nominal pixel size of 15 microns at the plane of the specimen. Scanning a ruby sphere phantom independently assessed the resolution of the system. The full width at half-maximum of the plane spread function is nominally 53 microns in the axial direction and 60 microns in the transverse plane. The visualization of the x-ray data consists of several complimentary techniques, including a three-dimensional stack of the reconstructed tomogram slices with 30 micron reconstruction voxel, a 360 degree rotating view of the tooth comprised from a sequence of projection images processed for detail contrast enhancement and edge restoration, and a surface model of each tooth. In total, 237 human teeth representing multiple samples of each of the varied tooth types have been individually scanned, analyzed, and visualized to date. The set of tooth data is being compiled into a comprehensive human tooth atlas, which is to be made available on CD for students and investigators as a resource for anyone studying tooth morphology and mineralization.

Seifert, Allen; Flynn, Michael J.; Montgomery, Kevin; Brown, Paul

2004-05-01

331

Influence of dental materials on the tooth structure finite elements method study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Occlusal stress factors have gained increasing attention as causes of non carious cervical lesions. Restoring these defects can reduce stress concentrations in these lesions. The purpose of this study is to evaluate the behavior of dental materials used in tooth restoration and the effects of these materials on intact and restaurated tooth structure. Our study uses finite elements method (FEM) owing to its multiple advantages. In this study, we generated a bidimensional plane mathematical fin...

2011-01-01

332

Perceived need for local anesthesia in tooth drilling among Anglo-Americans, Chinese, and Scandinavians.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study explored ethnic differences in perceptions of pain and the need for local anesthesia for tooth drilling among age- and gender-matched Anglo-American, Mandarin Chinese, and Scandinavian dentists (n = 129) and adult patients (n = 396) using a systematic qualitative research strategy. Semistructured qualitative interviews determined: (a) the relative frequency of use or nonuse of anesthetic for similarly specified tooth drilling, (b) the reasons for nonuse of anesthetic as reported by...

Moore, R.; Bra?¸dsgaard, I.; Mao, T. K.; Miller, M. L.; Dworkin, S. F.

1998-01-01

333

Paradental cyst associated with supernumerary tooth fused with third molar: A rare case report  

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Fusion is the union of two tooth buds that are normally separated. Fusion is more frequent in deciduous teeth, particularly in the anterior region. The etiology of fusion is not known. It has been suggested that the pressure of adjacent dental follicles produces their contact and fusion before calcification. There is no difference between men and women in incidence. The term paradental cyst means that such type of cysts that are close proximity with the root of a tooth. A history of recurrent...

Prakash, A. Ravi; Reddy, P. Sreenivas; Rajanikanth, M.

2012-01-01

334

Immunohistochemical examination for the distribution of podoplanin-expressing cells in developing mouse molar tooth germs.  

Science.gov (United States)

We recently reported the expression of podoplanin in the apical bud of adult mouse incisal tooth. This study was aimed to investigate the distribution of podoplanin-expressing cells in mouse tooth germs at several developing stages. At the bud stage podoplanin was expressed in oral mucous epithelia and in a tooth bud. At the cap stage podoplanin was expressed on inner and outer enamel epithelia but not in mesenchymal cells expressing the neural crest stem cell marker nestin. At the early bell stage nestin and podoplanin were expressed in cervical loop and odontoblasts. At the root formation stage both nestin and podoplanin were weakly expressed in odontoblasts generating radicular dentin. Podoplanin expression was also found in the Hertwig epithelial sheath. These results suggest that epithelial cells of developing tooth germ acquire the ability to express nestin, and that tooth germ epithelial cells maintain the ability to express podoplanin in oral mucous epithelia. The expression of podoplanin in odontoblasts was induced as tooth germ development advanced, but was suppressed with the completion of the primary dentin, suggesting that podoplanin may be involved in the cell growth of odontoblasts. Nestin may function as an intermediate filament that binds podoplanin in odontoblasts. PMID:21060740

Imaizumi, Yuri; Amano, Ikuko; Tsuruga, Eichi; Kojima, Hiroshi; Sawa, Yoshihiko

2010-10-27

335

Variation of tooth number in mammalian dentition: connecting genetics, development, and evolution.  

Science.gov (United States)

A major question in modern biology is how gene mutations affect development and are translated into macroevolutionary changes in morphology. Variations in tooth number, a strategy used by many mammals to develop specialized dentitions, has been an important factor for species diversification. Changes in the number of teeth tend to occur in the reverse of the order teeth are formed during development, which also characterizes the general pattern of tooth loss observed during the evolution of placental mammals. To understand how changes at the molecular level affect the distinct stages of tooth development, we analyzed the ontogenesis of tooth growth arrest in sciurids and mice and in single and double knockout mutant mice. We show that the complexity of the genetic network that governs tooth development can change during ontogenetic trajectory, and these changes may be related to macroevolutionary changes. Furthermore, we show that the variation in tooth number in the affected members of human families bearing mutations in the MSX1 and PAX9 genes can help to understand how the genetic variations within a population can modulate evolutionary changes in dental patterning. PMID:12752768

Line, Sergio R P

2003-01-01

336

The Biomechanical Function of Periodontal Ligament Fibres in Orthodontic Tooth Movement  

Science.gov (United States)

Orthodontic tooth movement occurs as a result of resorption and formation of the alveolar bone due to an applied load, but the stimulus responsible for triggering orthodontic tooth movement remains the subject of debate. It has been suggested that the periodontal ligament (PDL) plays a key role. However, the mechanical function of the PDL in orthodontic tooth movement is not well understood as most mechanical models of the PDL to date have ignored the fibrous structure of the PDL. In this study we use finite element (FE) analysis to investigate the strains in the alveolar bone due to occlusal and orthodontic loads when PDL is modelled as a fibrous structure as compared to modelling PDL as a layer of solid material. The results show that the tension-only nature of the fibres essentially suspends the tooth in the tooth socket and their inclusion in FE models makes a significant difference to both the magnitude and distribution of strains produced in the surrounding bone. The results indicate that the PDL fibres have a very important role in load transfer between the teeth and alveolar bone and should be considered in FE studies investigating the biomechanics of orthodontic tooth movement. PMID:25036099

McCormack, Steven W.; Witzel, Ulrich; Watson, Peter J.; Fagan, Michael J.; Groning, Flora

2014-01-01

337

[Adult tooth loss profile in accordance with social capital and demographic and socioeconomic characteristics].  

Science.gov (United States)

Demographic and socioeconomic conditions play an important role in tooth loss in the population, however, there is little scientific evidence regarding the influence of social capital on this outcome. The scope of this study was to describe the tooth loss profile of adults aged 35-44, who are residents of the surrounding area of the city of Belo Horizonte in the state of Minas Gerais. This cross-sectional exploratory study comprised a sample of 1,013 adults. The dependent variable was tooth loss. Exploratory variables were social capital, demographic and socioeconomic characteristics. The Chi-squared Automatic Interaction Detector (CHAID) was used to map the adult tooth loss profile which was explained by low levels of social capital (47.0%; p < 0.001), more elderly adults (60.2%; p < 0.001), and low education levels (66.3%; p = 0.022). In the high social capital group, age was the determinant factor of tooth loss, irrespective of educational level or per capita income. The conclusion, at the individual level, is that social capital as well as demographic and socio economic characteristics explained the adult tooth loss profile. Individual social capital may have attenuated the negative influence of socioeconomic factors in the population under scrutiny. PMID:24897484

Borges, Carolina Marques; Campos, Ana Cristina Viana; Vargas, Andrea Maria Duarte; Ferreira, Efigênia Ferreira E

2014-06-01

338

Influences of multiple tooth-loss on signal travel in the insular cortex of rats.  

Science.gov (United States)

The insular cortex (IC) processes various kinds of sensory and emotional information. Multiple tooth-loss induces impairment of oral sensory and motor functions, which might result in the up- or down-regulation of signal processing in the IC. In the present study, we investigated how multiple tooth-loss affects neural activities in the IC. Slices of the IC were prepared from control (untreated) rats and rats raised following the loss of their upper molar teeth, and optical recordings with voltage-sensitive dye were made. Electrical stimulation was delivered to the agranular IC (AIC). The velocity of optical signal from the AIC to the granular IC (GIC) decreased in multiple tooth-loss rats compared with control rats. Field potentials from the GIC were recorded. Onset times of evoked response at the GIC recorded from multiple tooth-loss rats were prolonged compared with those recorded from control rats, suggesting that signal velocity in multiple tooth-loss rats had decreased. A reduced signal velocity was accompanied by neuronal loss in the GIC, which was confirmed by counting the cell numbers on Nissl-stained sections. Thus, multiple tooth-loss may have influences on the GIC where signal processing speed decreases. PMID:24666099

Kawabe, Mamichi; Yoshimura, Hiroshi

2014-06-01

339

Continued root formation after delayed replantation of an avulsed immature permanent tooth.  

Science.gov (United States)

Introduction. Tooth avulsion in the young permanent dentition is a frequent finding, and its prognosis depends on the treatment of the avulsed tooth before replantation, the extra-alveolar time, the storage medium, and the patient's general health. The present report describes management of an immature avulsed lower central incisor 90 minutes after the accident. Methods. A right lower central incisor of a 7-year-old girl was avulsed, and it was soaked in a glass of milk. 90 minutes after avulsion, replantation was performed, and the tooth was splinted; but after two weeks the replanted tooth's pulp was necrotic. Thus, endodontic treatment was performed and root canal was filled using a calcium hydroxide and iodoform paste (Metapex). Three months later, the intracanal medication was washed out and the canal was sealed using an apical plug of calcium enriched mixture (CEM) cement. Results. 20 months after replantation the tooth was completely asymptomatic, with physiologic mobility. Also, continued root formation including an apical segment beyond the artificial apical plug was observed. Conclusion. Creation of an appropriate apical barrier following the disinfection of root canal system promoted continued root-end growth in a replanted immature permanent tooth. PMID:24900928

Moradi Majd, Nima; Zohrehei, Heidar; Darvish, Alireza; Homayouni, Hamed; Adel, Mamak

2014-01-01

340

Comparative qualitative and quantitative assessment of biomineralization of tooth development in man and zebrafish (Danio rerio).  

Science.gov (United States)

It was the aim of this study to investigate the distribution of Ca, P, and C in predentin, mineralizing dentin, and mature dentin of human tooth buds and compare these results with those of zebrafish (Danio rerio) teeth using energy dispersive X-ray analysis (EDX) element analysis. The mandible of a 16-week-old human fetus containing 6 mineralizing tooth buds and three complete heads of zebrafish were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80-microm thickness were cut in frontal-dorsal direction, and from these sections, polarized light micrographs were taken. The sections with tooth buds were then investigated with scanning electron microscopy, and EDX element analysis was performed with a Philips XL 30 FEG scanning microscope and an EDAX energy-dispersive X-ray system using spot measurements, EDX line-scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, and mature dentin. The Ca and P content increased rapidly from outer predentin toward mineralizing dentin in human tooth buds and in zebrafish teeth. The Ca/P ratio was different for predentin and dentin areas, reflecting different calcium phosphate compositions in predentin and fully mineralized dentin. Because of the similarities between human tooth buds and zebrafish teeth, it can be concluded that the zebrafish tooth development may be an excellent model for studying biomineralization processes during odontogenesis. PMID:18383276

Arnold, Wolfgang H; Naumova, Kateryna I; Naumova, Ella A; Gaengler, Peter

2008-05-01

 
 
 
 
341

Immunohistochemical Examination for the Distribution of Podoplanin-Expressing Cells in Developing Mouse Molar Tooth Germs  

Science.gov (United States)

We recently reported the expression of podoplanin in the apical bud of adult mouse incisal tooth. This study was aimed to investigate the distribution of podoplanin-expressing cells in mouse tooth germs at several developing stages. At the bud stage podoplanin was expressed in oral mucous epithelia and in a tooth bud. At the cap stage podoplanin was expressed on inner and outer enamel epithelia but not in mesenchymal cells expressing the neural crest stem cell marker nestin. At the early bell stage nestin and podoplanin were expressed in cervical loop and odontoblasts. At the root formation stage both nestin and podoplanin were weakly expressed in odontoblasts generating radicular dentin. Podoplanin expression was also found in the Hertwig epithelial sheath. These results suggest that epithelial cells of developing tooth germ acquire the ability to express nestin, and that tooth germ epithelial cells maintain the ability to express podoplanin in oral mucous epithelia. The expression of podoplanin in odontoblasts was induced as tooth germ development advanced, but was suppressed with the completion of the primary dentin, suggesting that podoplanin may be involved in the cell growth of odontoblasts. Nestin may function as an intermediate filament that binds podoplanin in odontoblasts. PMID:21060740

Imaizumi, Yuri; Amano, Ikuko; Tsuruga, Eichi; Kojima, Hiroshi; Sawa, Yoshihiko

2010-01-01

342

Continued Root Formation after Delayed Replantation of an Avulsed Immature Permanent Tooth  

Science.gov (United States)

Introduction. Tooth avulsion in the young permanent dentition is a frequent finding, and its prognosis depends on the treatment of the avulsed tooth before replantation, the extra-alveolar time, the storage medium, and the patient's general health. The present report describes management of an immature avulsed lower central incisor 90 minutes after the accident. Methods. A right lower central incisor of a 7-year-old girl was avulsed, and it was soaked in a glass of milk. 90 minutes after avulsion, replantation was performed, and the tooth was splinted; but after two weeks the replanted tooth's pulp was necrotic. Thus, endodontic treatment was performed and root canal was filled using a calcium hydroxide and iodoform paste (Metapex). Three months later, the intracanal medication was washed out and the canal was sealed using an apical plug of calcium enriched mixture (CEM) cement. Results. 20 months after replantation the tooth was completely asymptomatic, with physiologic mobility. Also, continued root formation including an apical segment beyond the artificial apical plug was observed. Conclusion. Creation of an appropriate apical barrier following the disinfection of root canal system promoted continued root-end growth in a replanted immature permanent tooth. PMID:24900928

Moradi Majd, Nima; Darvish, Alireza; Adel, Mamak

2014-01-01

343

Smoking and tooth discolouration: findings from a national cross-sectional study  

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Full Text Available Abstract Background Smoking is a risk factor of a number of oral diseases; the extent to which tobacco products influence dental aesthetics has not been widely investigated. The aim of this study was to determine satisfaction with own tooth colour of smokers and non-smokers and to investigate whether smokers have higher levels of self-assessed tooth discolouration compared to non-smokers Methods A cross sectional national study was conducted on sample of 6,000 UK adults. A total of 3,384 adults was interviewed. Smoking behaviour was recorded together with satisfaction with own tooth colour. Prevalence of perceived discolouration was measured by asking respondents to match their own tooth colour to one of a set of seven photographs of differing severities of discolouration. Results Twenty eight percent of smokers reported having moderate and severe levels of tooth discolouration compared to 15% in non-smokers. As well as more often perceiving discolouration smokers were also more likely to be dissatisfied with their own tooth colour compared to non-smokers. Conclusion The study provides further evidence of the negative impact of tobacco smoking on dental aesthetics in the general public. The evidence provided by the study may be of value in short interventions for smoking cessation in the dental setting.

Holt Ruth D

2005-03-01

344

Molecular characterization of dental development in a toothed archosaur, the American alligator Alligator mississippiensis.  

Science.gov (United States)

Few skeletal structures are as informative of the adaptive natural history of vertebrate animals as their teeth. Understanding principles of tooth development is key to understanding evolution of the vertebrate dentition in general and emergence of multiple specialized tooth types in particular. Morphological and phylogenetic considerations suggest that crocodilians have the most primitive mode of dentition within extant tetrapods, displaying simple, conical, socketed, and continuously replaced teeth. Previous histological studies revealed several dental fates, including functional and non-functional teeth (rudiments) in the developing alligator embryos. We analyze expression of key odontogenic regulators and markers to better characterize the molecular patterning of crocodilian dentition. Importantly, we demonstrate that the morphologically distinct tooth types in Alligator mississippiensis are distinguishable by differences in their developmental programs. We also present evidence showing that tooth maturation is accompanied by dynamic gene expression in the epithelial and mesenchymal cells involved in tooth development. Our data reveal a significant morphological and genetic variation in early dental fates. We believe that this underlying developmental variation reflects modularity, or the ability of teeth to develop semi-autonomously along the alligator jaw. We propose that such modularity may have been a crucial for adaptive evolution within Amniota, allowing for the progressive modifications to tooth replacement, number, and shape. PMID:24261441

Weeks, Olivia; Bhullar, Bhart-Anjan S; Abzhanov, Arhat

2013-01-01

345

Ferulizaciones diente-implante Tooth to implant splinting  

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Full Text Available Se presenta una revisión sobre la posibilidad terapéutica del empleo de la ferulización entre dientes e implantes. Tras una breve introducción, se establece una serie de diferencias biomecánicas entre dos estructuras tan dispares como son el diente y el implante. Posteriormente, se exponen una serie de puntos que los distintos autores han achacado a este sistema protésico para luego describir los distintos diseños que se pueden aplicar (rígidos y semirrígidos. A continuación, se efectúa una revisión bibliográfica acerca de la evolución a corto y largo plazo de estos sistemas. Por último, se elabora una relación de ventajas, desventajas e indicaciones de la ferulización diente-implante, para terminar estableciendo unas conclusiones.A review about the tooth-implant splinting therapeutic option is presented. After a brief introduction, it begins with some biomechanical aspects. Then, some critical points about this kind of frames are shown in order to, afterwards, describe de different design that can be applied. A short and long-term evolution of these systems is also made and, finally, we can see some advantages, disadvantages and indications for the splinting option, to finish establishing some conclusions.

G. Hernández

2005-12-01

346

Charcot-Marie-Tooth Disease Type 2B  

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Full Text Available Chatcot-Marie-Tooth (CMT is also known as peroneal muscular atrophy and hereditary motor-sensory neuropathy (HMSN. It is the most commonly encountered inherited peripheral neuropathy. Actually, CMT is not a single disease, but is a group of disorders with similar symptoms. CMT type 2 is the second most common form after CMT type1. Symptoms usually begin in childhood or early adulthood. Mostly the peripheral nerves of the lower extremities and occasionaly upper extremities may be affected. Motor nerve involvoment induces distal muscle weakness and atrophy in the lower extremities that may result in foot deformities known as foot drop, pes cavus, pes planus, hammer toe etc. As a result of sensorial nevre degeneration, callus, recurrent foot ulcers, osteonecrosis, osteolysis and spontaneous amputation may accompany the disease. The speed of nerve conduction is not changed in the EMG, but axonal type sensorymotor semptoms that lead to a decrease of amplitude. We report here a 55 year old man with recurrent foot ulcers for 33 years and self amputations, whose EMG findings suggest acsonal neuropathy and who also has a 20 year - old son with similar complaints.

?enay Durdu

2009-06-01

347

Autosomal recessive forms of Charcot-Marie-Tooth disease.  

Science.gov (United States)

In some countries with a high prevalence of consanguineous marriages, autosomal recessive inheritance is likely to account for the great majority of all forms of Charcot-Marie-Tooth (CMT) disease. As with the dominant forms, it is usual to differentiate the demyelinating forms (autosomal recessive -CMT1 or AR-CMT4) from the axonal forms (AR-CMT2). Genetic analysis of large families with recessive transmission has proved to be an efficient mean of discovering novel CMT genotypes (eg, the genes GDAP1, MTMR2, MTMR13, KIAA1985, NDGR1, periaxin, and lamin). Because of the clinical, electrophysiologic, and histologic heterogeneity of these patients, it is likely that there are numerous genes that remain to be discovered, which will probably make classification even more complex. Clinical, and especially histologic, phenotypes often lead to a suspicion that a specific gene is implicated. There is, therefore, an indication for nerve biopsy to orient diagnostic research in molecular biology, which is presently very time consuming and can only be performed in highly specialized laboratories. PMID:15324608

Vallat, J M; Grid, D; Magdelaine, C; Sturtz, F; Tazir, M

2004-09-01

348

Control of erosive tooth wear: possibilities and rationale  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Dental erosion is a type of wear caused by non bacterial acids or chelation. There is evidence of a significant increase in the prevalence of dental wear in the deciduous and permanent teeth as a consequence of the frequent intake of acidic foods and drinks, or due to gastric acid which may reach th [...] e oral cavity following reflux or vomiting episodes. The presence of acids is a prerequisite for dental erosion, but the erosive wear is complex and depends on the interaction of biological, chemical and behavioral factors. Even though erosion may be defined or described as an isolated process, in clinical situations other wear phenomena are expected to occur concomitantly, such as abrasive wear (which occurs, e.g, due to tooth brushing or mastication). In order to control dental loss due to erosive wear it is crucial to take into account its multifactorial nature, which predisposes some individuals to the condition.

Mônica Campos, Serra; Danielle Cristine Furtado, Messias; Cecilia Pedroso, Turssi.

349

Unsuspected functional disparity in Devonian fishes revealed by tooth morphometrics?  

Science.gov (United States)

The shape of features involved in key biological functions, such as teeth in nutrition, can provide insights into ecological processes even in ancient time, by linking the occupation of the morphological space (disparity) to the occupation of the ecological space. Investigating disparity in radiating groups may provide insights into the ecological diversification underlying evolution of morphological diversity. Actinopterygian fishes initiated their radiation in the Devonian, a period characterized by the diversification of marine ecosystem. Although a former morpho-functional analysis of jaw shape concluded to conservative and poorly diversified morphologies in this early part of their history, fish tooth disparity evidenced here an unsuspected diversity of possible functional significance in the pivotal period of the Late Devonian (Famennian). All teeth being caniniforms, some were stocky and robust, in agreement with expectations for active generalist predators. More surprisingly, elongated teeth also occurred at the beginning of Famennian. Their needle-like shape challenges morpho-functional interpretations by making them fragile in response to bending or torsion. The occurrence of both types of fish teeth during the beginning of the Famennian points to a discrete but real increase in disparity, thus testifying a first burst of feeding specialization despite overall conservative jaw morphology. The disappearance of these needle-like teeth in the Late Famennian might have been related to a relay in dental diversity with abundant co-occurring groups, namely conodonts and chondrichthyans (sharks).

Gauchey, Samuel; Girard, Catherine; Adnet, Sylvain; Renaud, Sabrina

2014-09-01

350

Effect of the 308-nm excimer laser on tooth dentin  

Science.gov (United States)

The use of the laser for applications in electronics, industry and medicine is growing at a rapid pace. Dental applications for lasers, developed to date, have primarily been used for surgery on soft tissues. The pulsed output of the 308 nm excimer laser and the photochemical rather than photothermal action offers the ability to cut on dental structures with minimal generation of heat. In a previous study the action of the 308 nm excimer laser on dental enamel was demonstrated. This study showed that a hole of controlled diameter and depth could be produced. The study has now been extended to determine the effect of the 308 nm excimr laser on dentin. Energy densities of 50, 70 and 90 mJ/mm' were used while exposing points on the dentin surface 500, 1000, 1500, 3000 and 4000 pulses (each 100 pulses equal to 5 seconds time). Tooth samples were rigidly fixed in position while the laser beam was transmitted to the dentin surface through a uv-grade fused silica fiber optic light guide, 600 microns in core diameter. Results showed that a symmetrical hole could be produced in the dentin surface, accurately controlling diameter and depth of penetration. Further results demonstrated that the dentin smear layer was removed and the dentinal tubules could be sealed with the 308 nm excimer laser.

Hame, Heidi; Voss, R.; Papaioannou, Thanassis; Grundfest, Warren S.; Johnson, R.

1990-06-01

351

Sensory ability in the narwhal tooth organ system.  

Science.gov (United States)

The erupted tusk of the narwhal exhibits sensory ability. The hypothesized sensory pathway begins with ocean water entering through cementum channels to a network of patent dentinal tubules extending from the dentinocementum junction to the inner pulpal wall. Circumpulpal sensory structures then signal pulpal nerves terminating near the base of the tusk. The maxillary division of the fifth cranial nerve then transmits this sensory information to the brain. This sensory pathway was first described in published results of patent dentinal tubules, and evidence from dissection of tusk nerve connection via the maxillary division of the fifth cranial nerve to the brain. New evidence presented here indicates that the patent dentinal tubules communicate with open channels through a porous cementum from the ocean environment. The ability of pulpal tissue to react to external stimuli is supported by immunohistochemical detection of neuronal markers in the pulp and gene expression of pulpal sensory nerve tissue. Final confirmation of sensory ability is demonstrated by significant changes in heart rate when alternating solutions of high-salt and fresh water are exposed to the external tusk surface. Additional supporting information for function includes new observations of dentinal tubule networks evident in unerupted tusks, female erupted tusks, and vestigial teeth. New findings of sexual foraging divergence documented by stable isotope and fatty acid results add to the discussion of the functional significance of the narwhal tusk. The combined evidence suggests multiple tusk functions may have driven the tooth organ system's evolutionary development and persistence. PMID:24639076

Nweeia, Martin T; Eichmiller, Frederick C; Hauschka, Peter V; Donahue, Gretchen A; Orr, Jack R; Ferguson, Steven H; Watt, Cortney A; Mead, James G; Potter, Charles W; Dietz, Rune; Giuseppetti, Anthony A; Black, Sandie R; Trachtenberg, Alexander J; Kuo, Winston P

2014-04-01

352

Aging and Fracture of Human Cortical Bone and Tooth Dentin  

Energy Technology Data Exchange (ETDEWEB)

Mineralized tissues, such as bone and tooth dentin, serve as structural materials in the human body and, as such, have evolved to resist fracture. In assessing their quantitative fracture resistance or toughness, it is important to distinguish between intrinsic toughening mechanisms which function ahead of the crack tip, such as plasticity in metals, and extrinsic mechanisms which function primarily behind the tip, such as crack bridging in ceramics. Bone and dentin derive their resistance to fracture principally from extrinsic toughening mechanisms which have their origins in the hierarchical microstructure of these mineralized tissues. Experimentally, quantification of these toughening mechanisms requires a crack-growth resistance approach, which can be achieved by measuring the crack-driving force, e.g., the stress intensity, as a function of crack extension ("R-curve approach"). Here this methodology is used to study of the effect of aging on the fracture properties of human cortical bone and human dentin in order to discern the microstructural origins of toughness in these materials.

Ager, Joel; Koester, Kurt J.; Ager III, Joel W.; Ritchie, Robert O.

2008-05-07

353

Endodontic therapy of pathological resorptions of tooth root  

Directory of Open Access Journals (Sweden)

Full Text Available Pathological resorptions of a tooth root very often represent both a diagnostic and therapeutical problem. The goal of this study was, based on clinical research on a number of pathological resorptions of various types and localization in relation to time, to analyze and evaluate applied endodontic therapy. Clinical research covered 30 patients (40 root canals in total. 18 teeth (22 canal with external and 12 (18 canal with internal root resorptions received endodontic therapy. After standard endodontic procedure had been applied (cleaning and canal shaping calcium hydroxide paste was used as a canal medicament for cases with internal resorptions and calcium hydroxide paste and points for cases with external resorptions. Canal opturations were done by modified technique of lateral condesation applying AH- Plus paste. The obtained results showed that in cases of internal resorption after 12 months, 11 cases were successful and only 1 failure occurred. In case of external resorption, after the same period of time, 15 cases were successful and failures occurred in 3 cases. The success of resorption treatment depends on many factors but, primarily, it depends on time and accuracy of diagnosis and properly applied treatment and root canal opturation.

Opa?i?-Gali? Vanja

2004-01-01

354

Control of erosive tooth wear: possibilities and rationale  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Dental erosion is a type of wear caused by non bacterial acids or chelation. There is evidence of a significant increase in the prevalence of dental wear in the deciduous and permanent teeth as a consequence of the frequent intake of acidic foods and drinks, or due to gastric acid which may reach th [...] e oral cavity following reflux or vomiting episodes. The presence of acids is a prerequisite for dental erosion, but the erosive wear is complex and depends on the interaction of biological, chemical and behavioral factors. Even though erosion may be defined or described as an isolated process, in clinical situations other wear phenomena are expected to occur concomitantly, such as abrasive wear (which occurs, e.g, due to tooth brushing or mastication). In order to control dental loss due to erosive wear it is crucial to take into account its multifactorial nature, which predisposes some individuals to the condition.

Mônica Campos, Serra; Danielle Cristine Furtado, Messias; Cecilia Pedroso, Turssi.

2009-06-01

355

Pé cavo adquirido na doença de Charcot-Marie-Tooth / Acquired pes cavus in Charcot-Marie-Tooth disease  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese As neuropatias sensitivomotoras hereditárias, principalmente a doença de Charcot-Marie-Tooth, manifestam-se frequentemente com o aparecimento de pé cavovaro, deformidade caracterizada pela acentuação fixa do arco plantar e inversão do retropé. O diagnóstico da doença de base e a cuidadosa avaliação [...] do paciente fornecem os elementos-chave para decisão do tratamento. O cavo pode situar-se no antepé, retropé ou ser o resultado da associação das duas localizações. Deformidades combinadas, principalmente varismo e garras dos artelhos, devem ser bem avaliadas; as características clínicas como grau das alterações, acometimento da força muscular, flexibilidade e idade são fatores importantes para a decisão da conduta. O tratamento conservador do pé cavovaro por meio de fisioterapia, palmilhas e adaptação nos calçados é reservado ao paciente mais jovem ou casos levemente acometidos. Entretanto, há tendência de agravamento das deformidades devido à característica progressiva da doença neurológica de base. Assim, o tratamento cirúrgico pelas técnicas clássicas é indicado precocemente, sendo importante identificar as alterações primárias, diferenciá-las das secundárias e corrigi-las, se possível. As transferências musculares são usadas no sentido de minimizar o desequilíbrio, estruturas retraídas são seccionadas ou alongadas e osteotomias localizadas devem ser preferíveis às artrodeses, que são reservadas para pés rígidos e muito deformados de pacientes adultos. Abstract in english Hereditary motor and sensory neuropathies, especially Charcot-Marie-Tooth disease, are frequently expressed with an acquired cavusvarus foot which is characterized by a fixed increase of the plantar arch and hindfoot inversion. Diagnosis of the underlying condition achieved through careful patient a [...] ssessment and local evaluations is the keystone for decision-making about the adequate treatment. The cavus may present as an isolated deformity of the forefoot, hindfoot or it may be a combination of both locations. Related deformities, mainly the varus and toe clawing require appropriate evaluation; clinical characteristics such as severity of the deformity, impairment of the muscular power, flexibility and patient's age are important characteristics in the treatment decision. Conservative treatment of the cavusvarus foot with physiotherapy, insoles and shoe modifications are reserved to young patients and mild deformities. However, there is a tendency of the deformity to become more severe over time because of the progressive feature of the underlying neurological condition. So, the surgical treatment by using classical techniques is performed in early stages. Most importantly is the identification of the primary and main components of each deformity to properly correct them, if possible. Muscular transfers are used to treat the dynamic unbalance, retracted structures should be either divided or lengthened and localized osteotomies should be preferred over arthrodeses, which are reserved for stiff and severely deformed feet in adults.

Daniel Augusto Carvalho, Maranho; José Batista, Volpon.

356

Pé cavo adquirido na doença de Charcot-Marie-Tooth Acquired pes cavus in Charcot-Marie-Tooth disease  

Directory of Open Access Journals (Sweden)

Full Text Available As neuropatias sensitivomotoras hereditárias, principalmente a doença de Charcot-Marie-Tooth, manifestam-se frequentemente com o aparecimento de pé cavovaro, deformidade caracterizada pela acentuação fixa do arco plantar e inversão do retropé. O diagnóstico da doença de base e a cuidadosa avaliação do paciente fornecem os elementos-chave para decisão do tratamento. O cavo pode situar-se no antepé, retropé ou ser o resultado da associação das duas localizações. Deformidades combinadas, principalmente varismo e garras dos artelhos, devem ser bem avaliadas; as características clínicas como grau das alterações, acometimento da força muscular, flexibilidade e idade são fatores importantes para a decisão da conduta. O tratamento conservador do pé cavovaro por meio de fisioterapia, palmilhas e adaptação nos calçados é reservado ao paciente mais jovem ou casos levemente acometidos. Entretanto, há tendência de agravamento das deformidades devido à característica progressiva da doença neurológica de base. Assim, o tratamento cirúrgico pelas técnicas clássicas é indicado precocemente, sendo importante identificar as alterações primárias, diferenciá-las das secundárias e corrigi-las, se possível. As transferências musculares são usadas no sentido de minimizar o desequilíbrio, estruturas retraídas são seccionadas ou alongadas e osteotomias localizadas devem ser preferíveis às artrodeses, que são reservadas para pés rígidos e muito deformados de pacientes adultos.Hereditary motor and sensory neuropathies, especially Charcot-Marie-Tooth disease, are frequently expressed with an acquired cavusvarus foot which is characterized by a fixed increase of the plantar arch and hindfoot inversion. Diagnosis of the underlying condition achieved through careful patient assessment and local evaluations is the keystone for decision-making about the adequate treatment. The cavus may present as an isolated deformity of the forefoot, hindfoot or it may be a combination of both locations. Related deformities, mainly the varus and toe clawing require appropriate evaluation; clinical characteristics such as severity of the deformity, impairment of the muscular power, flexibility and patient's age are important characteristics in the treatment decision. Conservative treatment of the cavusvarus foot with physiotherapy, insoles and shoe modifications are reserved to young patients and mild deformities. However, there is a tendency of the deformity to become more severe over time because of the progressive feature of the underlying neurological condition. So, the surgical treatment by using classical techniques is performed in early stages. Most importantly is the identification of the primary and main components of each deformity to properly correct them, if possible. Muscular transfers are used to treat the dynamic unbalance, retracted structures should be either divided or lengthened and localized osteotomies should be preferred over arthrodeses, which are reserved for stiff and severely deformed feet in adults.

Daniel Augusto Carvalho Maranho

2009-01-01

357

Periapical tissue reactions to calcium hydroxide and MTA after external root resorption as a sequela of delayed tooth replantation.  

Science.gov (United States)

Clinical experience has shown that most avulsed teeth are replanted after a long extra-alveolar time and dry or inadequate wet storage, causing necrosis of periodontal ligament cells. This condition invariably leads to development of external root resorption, leaving the filling material in contact with the periapical connective tissues. In this study, the periapical tissue reactions to calcium hydroxide (CH) and mineral trioxide aggregate (MTA) were evaluated after occurrence of external root resorption as an expected sequela of delayed tooth replantation. Twenty male Wistar rats (Rattus norvegicus, albinus) had their right upper incisor extracted and maintained in dry storage for 60 min. Then, the dental papilla, enamel organ, pulp tissue, and periodontal ligament were removed, and the teeth were immersed in a 2% acidulated phosphate sodium fluoride solution, pH 5.5, for 10 min. The teeth were randomly assigned into two groups (n = 10), in which the canals were filled with either a CH and saline paste (CH group) or MTA (MTA group). The sockets were irrigated with saline, and the teeth were replanted. After 80 days, it was possible to observe large areas of replacement root resorption and some areas of inflammatory root resorption in both groups. More severe inflammatory tissue reaction was observed in contact with calcium hydroxide compared with the mineral trioxide aggregate. New bone formation was more intense at the bottom of the socket in the MTA group. In conclusion, as far as periapical tissue compatibility is concerned, intracanal MTA can be considered as a viable option for root canal filling in delayed tooth replantation, in which external root resorption is an expected sequela. PMID:22151580

Marão, Heloisa Fonseca; Panzarini, Sônia Regina; Aranega, Alessandra Marcondes; Sonoda, Celso Koogi; Poi, Wilson Roberto; Esteves, Jônatas Caldeiras; Silva, Pedro Ivo Santos

2012-08-01

358

Myelin protein zero gene sequencing diagnoses Charcot-Marie-Tooth Type 1B disease  

Energy Technology Data Exchange (ETDEWEB)

Charcot-Marie-Tooth disease (CMT), the most common genetic neuropathy, affects about 1 in 2600 people in Norway and is found worldwide. CMT Type 1 (CMT1) has slow nerve conduction with demyelinated Schwann cells. Autosomal dominant CMT Type 1B (CMT1B) results from mutations in the myelin protein zero gene which directs the synthesis of more than half of all Schwann cell protein. This gene was mapped to the chromosome 1q22-1q23.1 borderline by fluorescence in situ hybridization. The first 7 of 7 reported CMT1B mutations are unique. Thus the most effective means to identify CMT1B mutations in at-risk family members and fetuses is to sequence the entire coding sequence in dominant or sporadic CMT patients without the CMT1A duplication. Of the 19 primers used in 16 pars to uniquely amplify the entire MPZ coding sequence, 6 primer pairs were used to amplify and sequence the 6 exons. The DyeDeoxy Terminator cycle sequencing method used with four different color fluorescent lables was superior to manual sequencing because it sequences more bases unambiguously from extracted genomic DNA samples within 24 hours. This protocol was used to test 28 CMT and Dejerine-Sottas patients without CMT1A gene duplication. Sequencing MPZ gene-specific amplified fragments identified 9 polymorphic sites within the 6 exons that encode the 248 amino acid MPZ protein. The large number of major CMT1B mutations identified by single strand sequencing are being verified by reverse strand sequencing and when possible, by restriction enzyme analysis. This protocol can be used to distringuish CMT1B patients from othre CMT phenotypes and to determine the CMT1B status of relatives both presymptomatically and prenatally.

Su, Y.; Zhang, H.; Madrid, R. [Univ. of California, San Francisco, CA (United States)] [and others

1994-09-01

359

In vitro assessment of the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english This in vitro study evaluated the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains. Twenty dental blocks (4 x 4 mm), including enamel and dentine, removed from freshly extracted bovine incisors, were randomly divided into 4 groups: G1 - distilled water, G2 - Colgate, [...] G3 - Crest Extra Whitening and G4 - Rapid White. In all specimens, the dentin was covered with colorless nail polish, and the enamel was left exposed. Next, the specimens were immersed in a solution of black tea, which was changed every 24 h, for a period of 6 days. After this period, a photo-reflectance reading was taken (Time 1) with a spectrometer. The stained specimens were then submitted to linear brushing movements (5,000 cycles) using brushes (Oral B-Soft) coupled to an automatic toothbrushing machine, under a static axial load of 200 g and with a speed of 4 movements/second, at 37°C, with the dentifrice or water being injected every 60 s. When toothbrushing ended, a second photo-reflectance reading was taken (Time 2). The results were submitted to two-criteria analysis of variance (ANOVA) and to the Tukey test ( = 0.05). When the two times for a same group were compared, Time 2 presented the highest reflectance values with statistical difference only for G3 and G4. Among the dentifrices tested, only the Rapid White group differed from the control group, presenting the highest reflectance values. Only the whitening dentifrice Rapid White was effective for the removal of extrinsic stains.

Débora Alves Nunes Leite, Lima; André Luís Faria e, Silva; Flávio Henrique Baggio, Aguiar; Priscila Christiane Suzy, Liporoni; Egberto, Munin; Gláucia Maria Bovi, Ambrosano; José Roberto, Lovadino.

2008-06-01

360

LEF1 is a critical epithelial survival factor during tooth morphogenesis.  

Science.gov (United States)

LEF1 is a cell-type-specific transcription factor and mediates Wnt signaling pathway by association with its co-activator beta-catenin. Wnt signaling is known to be critical for the specification of cranial neural crest (CNC) cells and may regulate the fate diversity of the CNC during craniofacial morphogenesis. Loss of Lef1 results in arrested tooth development at the late bud stage and LEF1 is required for a relay of a Wnt signaling to a cascade of FGF signaling activities to mediate the epithelial-mesenchymal interaction during tooth morphogenesis. It remains unclear, however, what is the cellular mechanism of LEF1 signaling in regulating tooth morphogenesis. To test the hypothesis that LEF1 signaling regulates the fate of the dental epithelial and the CNC-derived mesenchymal cells during tooth morphogenesis, we investigated and compared the cellular migration, proliferation, and apoptotic activity within the tooth germ between the wild-type and Lef1 null mutant mice. Using the Wnt1-Cre/R26R transgenic system for indelibly marking the progenies of CNC cells, we show that there is no CNC migration defect in the Lef1 null mutant mice, indicating that the arrest in tooth development is not the result of shortage of the CNC contribution into the first branchial arch in the Lef1 mutant. Furthermore, there is no alteration in cell proliferation or condensation of the CNC-derived dental mesenchyme in the Lef1 null mutant, suggesting that LEF1 may not affect the cell cycle progression of the multipotential CNC cells during tooth morphogenesis. Importantly, apoptotic activity is significantly increased within the dental epithelium in the Lef1 null mutant mice. As the result of this increased cell death, the bud stage tooth germ fails to advance to the cap stage in the absence of Lef1. Inhibition of apoptotic activity by FGF4 rescues the tooth development in the Lef1 null mutant. Our studies suggest that LEF1 is a critical survival factor for the dental epithelial cells during tooth morphogenesis. PMID:15649466

Sasaki, Tomoyo; Ito, Yoshihiro; Xu, Xun; Han, Jun; Bringas, Pablo; Maeda, Takeyasu; Slavkin, Harold C; Grosschedl, Rudolf; Chai, Yang

2005-02-01

 
 
 
 
361

Moessbauer Studies of Stannous Fluoride Reactivity with Synthetic Tooth Enamel - A Model for the Tooth Cavity Protection Actions of Novel Dentifrices  

Energy Technology Data Exchange (ETDEWEB)

SnF{sub 2} is an important toothpaste ingredient, added for the provision of clinical efficacy for hard and soft tissue diseases and in breath protection. Synthetic calcium hydroxyapatite powders were exposed to liquid supernates (25 w/w% toothpaste water slurries, centrifuged) of Crest Gum Care (registered) (SnF{sub 2}) dentifrice. One-minute treatments were followed by 3x water washing, centrifugation and lyophilization. Post treatment, powders were analyzed by Moessbauer spectroscopy with 0.5-1 gram of treated apatite powder. Results show that tooth mineral stannous fluoride interactions include: (1) formation of surface reaction products with both Sn(II) and Sn(IV) oxidation states; (2) Sn-F binding on mineral surfaces with no evidence of SnO. The surface binding is, however, not pure Sn-F but contains contributions of other ligands, probably oxygens from surface phosphates or hydroxyl groups. Results also suggest that surface reacted stannous tin is oxidized with time, even when bound as a layer on the tooth surface. This study demonstrates for the first time the presence of Sn-F on tooth enamel post treatment and the contribution of passivation to long term stannous chemistry on tooth surfaces. The study also illustrates the practical applications of the Moessbauer technique.

Denes, Georges, E-mail: gdenes@vax2.concordia.ca; Muntasar, Abdualhafeed [Concordia University, Laboratory of Moessbauer Spectroscopy and Solid State Chemistry, Laboratories for Inorganic Materials, Department of Chemistry and Biochemistry (Canada); Kozak, Kathy M.; Baig, Arif A.; White, Donald J. [Procter and Gamble Company (United States)

2002-06-15

362

Reimplante intencional en diente geminado con lesión endoperio tipo IV: Reporte de caso Intentional replantation gemina injured in tooth type IV endoperio: Case report  

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Full Text Available En los dientes con geminación y lesiones periapicales no resueltas después de un tratamiento endodóntico se debe pensar no solo en un diagnostico endodóntico sino también periodontal, ya que estos dientes en el intento de separación pueden presentar surcos o fisuras que van desde el borde incisal hasta la raíz convirtiéndose en un canal de comunicación entre la zona apical y la cavidad oral. Para realizar el plan de tratamiento se debe tener en cuenta: sintomatología persistente, posterior a la terapia endodóntica, persistencia de fístula, lesión periapical de gran tamaño, bolsa periodontal, anatomía radicular palatina del órgano dentario (presunto canal palatino, y que la anatomía del diente sea favorable para realizar el procedimiento. La extracción y reimplante intencional es el tratamiento indicado en casos donde el tratamiento endodóntico fracasa y por la anomalía dental, la cirugía periapical también fallaría porque solo se eliminaría la lesión momentáneamente más no la que lo causa que es la comunicación entre la cavidad oral y la zona apical. Sin embargo, se sabe que esta opción de tratamiento puede traer riesgos y beneficios, incluyendo pérdida del diente o una posible anquilosis y con una de tasa de éxito del 42,9%. El presenta caso clínico describe la extracción y reimplante intencional en un diente geminado con una lesión periapical persistente de origen periodontal, con sintomatología y fístula, posterior a tratamiento endodóntico complejo, su evolución y éxito.In teeth with gemination and unresolved periapical lesions after endodontic treatment we must think not only in diagnosis but also periodontal endodontic, as these teeth in the attempt of separation may have grooves or cracks that go from the incisal edge to root becoming a channel of communication between the apical and oral cavity. To make the treatment plan should take into account: persistent symptoms, after endodontic therapy, persistent fistula, large periapical lesions, periodontal pocket, root anatomy of the tooth organ palate (palatine canal alleged and that the anatomy tooth is favorable to perform the procedure. The extraction and intentional replantation is the treatment in cases where the endodontic treatment fails and the anomaly dental periapical surgery also fail because only temporarily remove the lesion but not the cause it is the communication between the oral cavity and apical area. However, it is known that this treatment option can have risks and benefits, including tooth loss or possible ankylosis and with a success rate of 42.9%. The present case report describes the extraction and intentional replantation geminate tooth with a persistent periapical lesion of periodontal origin, with symptoms and fistula, after endodontic treatment complex, its evolution and success.

R.S. Rodríguez Rodríguez

2012-10-01

363

Fused primary first mandibular macromolar with a unique relation to its permanent successors: A rare tooth anomaly.  

Science.gov (United States)

Dental anomalies of number and forms may occur in the primary and permanent dentition. Various terms have been used to describe dental twinning anomalies: Germination, fusion, concrescence, double teeth, conjoined teeth, twinned teeth, geminifusion, and vicinifusion. Fused tooth is a developmental anomaly that is seen more frequently in the primary than the permanent dentition. Double tooth involving deciduous anterior teeth is found mostly in the mandible. Very few cases of nonsyndromic double primary molar have been reported in the literature. The succeeding permanent tooth is often found missing congenitally in the same region. This article reports a very rare unilateral occurrence of an anomalous, primary mandibular first macromolar formed by fusion with a dysmorphic premolar like supernumerary tooth in deciduous dentition period. Instead of agenesis of succedaneous tooth, the double tooth has been succeeded by normally developing mandibular first premolar in the same region. PMID:24883034

Dhindsa, Abhishek; Garg, Shalini; Damle, S G; Opal, Shireen; Singh, Tavleen

2013-04-01

364

Current Therapy for Charcot-Marie-Tooth Disease.  

Science.gov (United States)

Charcot-Marie-Tooth (CMT), or heritable peripheral neuropathies, is among the most frequent genetic neuromuscular disorders, with a prevalence of approximately 1:2500. Since 1991, remarkable advances have occurred in determining the precise genetic cause of many forms of CMT and in generating animal models of many of these disorders. However, these advances have not yet resulted in cures for CMT. Recently, potential treatments for the most common form of CMT, CMT-1A, have been shown in rodent models of the disorder. Treatment with onapristone, a progesterone antagonist, has improved the neuropathy of the CMT-1A rat. Treatment with large doses of ascorbic acid (vitamin C) has improved the neuropathy of the CMT-1A mouse. Multicentric trials with ascorbic acid are likely to start in the near future to assess if vitamin C supplementation is effective and what is the dosage required in humans to improve neurologic disability. Because of potential side effects with antiprogesterone therapy, particularly in women of child- bearing age, research is actively proceeding with progesterone antagonists to develop safe medications that also can be used in clinical trials of CMT-1A. Although no cures are available for CMT, there are many important treatments available for patients with CMT that can improve their quality of life and help them maintain their independence. Some of these therapies involve physiatry and orthopedic surgery. Others involve pain management. Lastly, there are potential concerns about medications or lifestyle issues that may exacerbate CMT. All of these issues will be discussed. PMID:15610704

Grandis, Marina; Shy, Michael E

2005-01-01

365

Tooth loss in individuals under periodontal maintenance therapy: prospective study  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english This prospective study aimed to evaluate the incidence, the underlying reasons, and the influence of predictors of risk for the occurrence of tooth loss (TL) in a program of Periodontal Maintenance Therapy (PMT). The sample was composed of 150 complier individuals diagnosed with chronic moderate-sev [...] ere periodontitis who had finished active periodontal treatment and were incorporated in a program of PMT. Social, demographic, behavioral and biological variables were collected at quarterly recalls, over a 12-month period. The effect of predictors of risk of and confounding for the dependent variable TL was tested by univariate and multivariate analysis, as well as the underlying reasons and the types of teeth lost. During the monitoring period, there was a considerable improvement in periodontal clinical parameters, with a stability of periodontal status in the majority of individuals. Twenty-eight subjects (18.66%) had TL, totaling 47 lost teeth (1.4%). The underlying reasons for TL were: periodontal disease (n = 34, 72.3%), caries (n = 3, 6.4%), prosthetic reasons (n = 9, 19.2%), and endodontic reasons (n = 1, 2.1%). Additionally, subjects with 10% of sites with probing depth between 4 and 6 mm were 5 times more likely to present TL (OR = 5.13, 95% CI 2.04-12.09). In this study, the incidence of TL was small and limited to few individuals. Additionally, gender and severity of periodontitis were significantly associated with TL during the monitoring period.

Telma Campos Medeiros, Lorentz; Luís Otávio Miranda, Cota; José Roberto, Cortelli; Andréia Maria Duarte, Vargas; Fernando Oliveira, Costa.

2010-06-01

366

Current concepts in the biology of orthodontic tooth movement.  

Science.gov (United States)

Adaptive biochemical response to applied orthodontic force is a highly sophisticated process. Many layers of networked reactions occur in and around periodontal ligament and alveolar bone cells that change mechanical force into molecular events (signal transduction) and orthodontic tooth movement (OTM). Osteoblasts and osteoclasts are sensitive environment-to-genome-to-environment communicators, capable of restoring system homeostasis disturbed by orthodontic mechanics. Five micro-environments are altered by orthodontic force: extracellular matrix, cell membrane, cytoskeleton, nuclear protein matrix, and genome. Gene activation (or suppression) is the point at which input becomes output, and further changes occur in all 5 environments. Hundreds of genes and thousands of proteins participate in OTM. Gene-directed protein synthesis, modification, and integration form the essence of all life processes, including OTM. Bone adaptation to orthodontic force depends on normal osteoblast and osteoclast genes that correctly express needed proteins at the right times and places. Cell membrane receptor-ligand docking is an important initiator of signal transduction and a discovery target for new bone-enhancing drugs. Despite progress in identification of regulatory molecules, the genetic mechanism of "orchestrated synthesis" between different cells, tissues, and systems remains largely unknown. Interpatient variation in mechanobiological response is most likely due to differences in periodontal ligament and bone cell populations, genomes, and protein expression patterns. Discovery of mutations in OTM-associated genes of orthodontic patients, including those regulating osteoclast bone-matrix acidification, chloride channel function, and osteoblast-derived mineral and protein matrices, will permit gene therapy to restore normal matrix and protein synthesis and function. Achieving selectivity in targeting abnormal genes, cells, and tissues is a major obstacle to safe and effective clinical application of gene engineering and stem-cell mediated tissue growth. Orthodontic treatment is likely to evolve into a combination of mechanics and molecular-genetic-cellular interventions: a change from shotgun to tightly focused communication with OTM cells. PMID:16627170

Masella, Richard S; Meister, Malcolm

2006-04-01

367

Prevalence of erosive tooth wear in risk groups.  

Science.gov (United States)

Individuals have different risks for developing erosive lesions depending on background, behavioural, dietary and medical variables. It is anticipated that people with regular impact of gastric juice, i.e. patients with eating disorders and gastroesophageal reflux disease (GERD) have a specially high risk of developing dental erosions; the same could be true for those with special diets, regular consumption of acidic beverages, medicine and drug intake and occupational exposure to acids. Eating disorders are associated with an increased occurrence, severity and risk for dental erosion, even though not all bulimic patients show a pathological level of tooth wear. There seems also to be a tendency that in the case of GERD, erosion is more common and more severe than in healthy controls. Regarding exogenous causes, many studies, though not all, document a positive association between the consumption of acidic beverages and dental erosions and there seems to be a dose-response relationship; however, further studies are necessary for a final statement. The same applies for the association between drug or medication intake or special diet and erosion prevalence. Though only few studies exist, there seems to be a tendency for an increase of erosion prevalence amongst persons abusively consuming alcohol. Some studies show an increased risk for dental erosion for employees testing wine or working in acid processing factories. Even though some associations between acid impact and erosion prevalence appear clear, the number of studies is small. There is a lack of controlled prevalence studies, making it difficult to give final statements for all risk groups. PMID:24993259

Schlueter, Nadine; Tveit, Anne Bjørg

2014-01-01

368

The Activity of Aspartate Aminotransferase During Canine Retraction (Bodily Tooth Movement in Orthodontic Treatment  

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Full Text Available The pattern of activity of aspartate aminotransferase enzyme (AST following canine distalization stage in orthodontic treatment is being investigated. The enzyme is released to the gingival crevis following tooth movement resulted from focal necrosis in the adjacent periodontal ligament. The finding of enzymatic response could enhance our understanding of the enzyme`s role during tooth movement. This study investigated the potential of AST as a biological marker to monitor tooth movement by determining its activity in Gingival Crevicular Fluid (GCF during bodily tooth movement (canine distalization. About 13 patients age between 14-26 years participated in the study. All patients had orthodontic treatment using fixed appliances. For every subject, one upper canine being the test tooth while contralateral canine served as control. Distalization force (100 g was applied only to the test tooth and GCF was collected from the mesial and distal sites of test and control teeth every week until week 12 (week 0, 1, 4, 8 and 12. The activity of AST in the GCF was determined spectrophotometrically (at 30°C, 340 nm. The AST activity in the GCF of test teeth in all patients significantly increased at week 1 (p<0.05 compared to control. The activities during the following weeks (4-12 were similar to one another and stabilized but significantly higher than week 1 (p<0.05. There was 100% increment of AST activity from week 1 to 4. AST activity in the distal site was also significantly higher (p<0.05 than the mesial site of test teeth. There is no difference in AST activities when age group (adult and adolescent were compared (p>0.05. The AST activity appears to be enhanced with the applied force and showed no differences between adult and adolescent patient. Therefore, AST has the potential as a biological marker to monitor progress of orthodontic tooth movement.

M. A.W. Rohaya

2008-01-01

369

Use of an Implant O-Ring Attachment for the Tooth Supported Mandibular Overdenture: A Clinical Report  

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Retention of a mandibular denture can be achieved by an implant-retained or natural tooth-retained bar and stud attachment in the anterior segment of the mandible. The same design principles holds true for both implant-retained and tooth-retained methods of anchoring the bar and stud attachment. A simple and cost effective treatment for more complex implant overdenture is the concept of conventional tooth-retained overdentures. When few firm teeth still remain in a compromised dentition, pres...

Guttal, Satyabodh S.; Tavargeri, Anand K.; Nadiger, Ramesh K.; Thakur, Srinath L.

2011-01-01

370

A two DOF simulation of meshing in spur gear sets with modelling of the effect of individual tooth mass  

Science.gov (United States)

A Two-Degree Of Freedom analytical model of meshing in a single-stage spur gear set was developed and used for time-domain dynamic simulation. Apart from the time-varying tooth stiffness, the individual tooth mass, reduced to the meshing point, was also taken into consideration and modeled. The simulations that were performed by means of MatLab software using numerical methods highlight the effect of the individual tooth mass in the dynamic response of the gear stage.

Komitopoulos, Nikolaos; Vakouftsis, Christos

2014-10-01

371

Pulp hyperthermia during tooth preparation: the effect of rotary--instruments, lasers, ultrasonic devices, and airborne particle abrasion.  

Science.gov (United States)

The rise in pulp temperature during restorative therapy can compromise vitality of the dental pulp. Of the various reasons for the increase in intrapulpal temperature, tooth preparation is considered to be the primary cause. This article describes the reasons for the rise in pulp temperature during various modalities of tooth preparation. The article also comments on the measures that need to be taken to avoid the risk of pulp hyperthermia during tooth preparation. PMID:23097827

Thomas, Manuel S; Kundabala, M

2012-09-01

372

Mandibular lateral incisor with four root canals: A unique case of double tooth diagnosed using multidetector computed tomography  

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Double tooth is a dental anomaly consequent to fusion of two or more teeth or gemination of a single tooth. This report describes a unique case of double tooth in relation to a mandibular lateral incisor exhibiting the presence of four root canals. The role of conventional radiography and advanced three-dimensional imaging techniques in the better assessment of complex root canal systems and their aid in endodontic management has also been highlighted.

Gupta, Sunil Kumar; Acharya, Shashi Rashmi; Ather, Amber; Gupta, Jaya [Manipal College of Dental Sciences, Manipal University, Manipal (India)

2013-06-15

373

"EFFICACY OF BARBERRY AQUEOUS EXTRACTS DENTAL GEL ON CONTROL OF PLAQUE AND GINGIVITIS "  

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Herbal extracts have been successfully used in dentistry as tooth cleaning and antimicrobial plaque agents. The aim of this study was to evaluate the clinical effects of a dental gel containing barberry extracts (from Berberis vulgaris) on gingivitis and microbial plaque control. A double blind clinical trial study was conducted in a dormitory on 45 boys aged 11-12 years having the same socioeconomic conditions. These students were divided into 3 groups; the first group (25 students) using ba...

Makarem, A.; Asodeh, N. Khalili R.

2007-01-01

374

Extraction '90  

International Nuclear Information System (INIS)

Over the past few years there has been a change in liquid-liquid solvent extraction from a process used mainly for metal recovery to more diverse areas such as pharmaceutical drug production. The conference reported here was organised by the Scottish Branch of the IChemE in association with AEA Technology Dounreay. The papers presented address the recent advances in solvent extraction, both industrial and academic, carried out in both the nuclear and non-nuclear fields. The broad areas covered are: extraction fundamentals, extraction from dilute solutions, sorption, extraction of biological products, and processes and equipment. (author)

375

Solvent extraction  

International Nuclear Information System (INIS)

A method has been developed for the solvent extraction of aqueous liquids to obtain materials from these liquids. An extractable component is yielded from a liquid, in which one adds the liquid and an essentially liquid-unsoluable solvent for the extractable component to a mixed zone. A liquid-liquid dispersion is formed in the mixed zone whose one phase is a solution of the extractable component in the solvent. The dispersion is led to a settling zone in which the dispersion phases separate under the influence of gravity and the solution of the extractable component in the solvent is obtained. (HK)

376

Stereomicroscopic study of the human tooth caries: clinical and morphological correlations  

Science.gov (United States)

Objectives: Stereomicroscopy allows a three-dimensional study of the images and of laterality at superior quality in comparison with other methods. Those advantages are given by the large examination fields and the wide work distances. The adding of the clinical and morphological data at the results gathered with stereomicroscopy and the stereo micrometry is useful in order to appreciate the deepness and the widening of the carious process, and the necessity to reconsider the therapeutically strategy. Materials and methods: During 2009-2011 the study material was represented by 10 surgically removed impacted third molars, and by 20 premolars extracted for orthodontic purposes, with closed and macroscopically apparently integer surfaces. 13 premolars with different degrees of carious affectation and periodontal lesions, which were surgically extracted without trauma, were also selected. The in situ measurements at the occlusal site were realized through the utilization of a fluorescent laser device - DIAGNOdent. The basic principles in stereomicroscopy stood at the base of the obliquely and circularly coaxial illumination techniques, one with optical alignment adjustment of the optical microscope and mechanical adjustment for the optimal illumination and micrometry. The Olympus Microscope SZ ×7 and an Olympus camera with 2,5 × digital zoom and a 3× optical zoom has been used to study the samples in stereomicroscopy and through polarized light it. Results: The DiagnoDent measured the following data: out of 43 apparently healthy teeth, 18 presented values between 2 and 13 (D1), 13 showed values between 14 and 24 (D2), 12 measured values over 24 (D3). After the histological examination in stereomicroscopy and in the polarized light: 25 teeth were healthy, 10 presented caries extended in dental enamel and 8 presented dentinal caries. Stereomicroscopy has allowed the morphological study, the color absorption, the appreciation of the lesions' deepness and substance loss that is very useful in grading the progression of the carious lesion. Conclusions: The stereomicroscopic study correlated with clinical and morphological data allowed to appreciate the extent of tissue involved in the carious process, but also the understanding of the enamel, dentine and cement matrix demineralization process, in proximity with the morpho-embryological markings of the human tooth structure.

Oancea, Roxana; Vasile, Liliana; Marchese, Cristian; Sava-Rosianu, Ruxandra

2012-06-01

377

Dynamics of Alloplastic Bone Grafts on an Early Stage of Corticotomy-Facilitated Orthodontic Tooth Movement in Beagle Dogs  

Science.gov (United States)

Alveolar augmented corticotomy is effective in accelerating orthodontic tooth movement, but the effect only lasts for a relatively short time. Therefore, the purpose of this study was to investigate the underlying biology of the immediate periodontal response to orthodontic tooth movement after a corticotomy with alloplastic bone grafts. The results demonstrated that measurable tooth movement began as early as 3 days after the intervention in beagle dogs. Based on the results and histological findings, augmented corticotomy-facilitated orthodontic tooth movement might enhance the condition of the periodontal tissue and the stability of the outcomes of orthodontic treatment.

Choi, Hyung-Joo; Kim, Tae-Woo

2014-01-01

378

Analysis of brain and muscle activity during low-level tooth clenching - a feasibility study with a novel biting device  

DEFF Research Database (Denmark)

In electromyographic (EMG) and functional magnetic resonance imaging (fMRI) studies, muscle and brain activity was compared during low levels of tooth clenching using a novel biting device to control bite force. A total of 21 healthy subjects performed motor tasks, comprising tooth clenching at 5, 10 and 20 N. During all measurements, subjects kept the novel bite device between the anterior teeth during tooth clenching. The EMG study (n = 15) characterised jaw muscle activity for the three motor tasks and demonstrated significant differences in root mean square (RMS) EMG amplitude between 5-, 10- and 20-N tooth clenching (F = 46·21, P 

Iida, T; Overgaard, Ann

2014-01-01

379

Knowledge of physical education teachers about emergency management of tooth avulsion  

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Full Text Available A great number of traumatic dental injuries occur at school, during sports-related activities. However, physical education teachers are often not prepared to provide emergency management of dental trauma in general and of tooth avulsion in particular. The aim of this study was to assess the knowledge of emergency management of tooth avulsion among physical education teachers at public and private schools of a city in southern Brazil. A questionnaire covering personal and professional information and eight multiple-choice questions to assess knowledge of emergency management of tooth avulsion was sent to 217 physical education teachers. Of a total of 217 questionnaires distributed, 102 returned. Only 23.5% of the teachers had received prior information on dental trauma. When asked about the fi rst action to be taken if faced with an avulsed tooth, only 12.7% informed they would attempt to replant the tooth. Fifty two teachers (51% were not aware of the optimum extraoral time. Signifi cant differences were found between teachers who had and who had not received prior information with regard to adequate transport medium and adequate time for replantation (chi-square, p = 0.03 and p = 0.02, respectively. There is a general lack of knowledge of emergency management of avulsed teeth among physical education teachers, pointing to an urgent need to implement regular, continuing education so as to increase the level of knowledge and improve prognosis of this important traumatic dental injury.

Claudia Londero Pagliarin

2011-01-01