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Tooth extraction  

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A tooth extraction is a procedure to remove a tooth from the gum socket. It is usually done by a general ... gum. If you need a more complex tooth extraction: You will be given sedation so you are ...

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Iatrogenic traumatic brain injury during tooth extraction.  

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An 8 yr old spayed female Yorkshire terrier was referred for evaluation of progressive neurological signs after a routine dental prophylaxis with tooth extractions. The patient was circling to the left and blind in the right eye with right hemiparesis. Neurolocalization was to the left forebrain. MRI revealed a linear tract extending from the caudal oropharynx, through the left retrobulbar space and frontal lobe, into the left parietal lobe. A small skull fracture was identified in the frontal bone through which the linear tract passed. Those findings were consistent with iatrogenic trauma from slippage of a dental elevator during extraction of tooth 210. The dog was treated empirically with clindamycin. The patient regained most of its normal neurological function within the first 4 mo after the initial injury. Although still not normal, the dog has a good quality of life. Traumatic brain injury is a rarely reported complication of extraction. Care must be taken while performing dental cleaning and tooth extraction, especially of the maxillary premolar and molar teeth to avoid iatrogenic damage to surrounding structures. PMID:25695556

Troxel, Mark

2015-01-01

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Necessity of analgesics prescription after tooth extraction  

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Full Text Available Introduction. For patients and surgeons, pain and discomfort associated with dento-alveolar surgery can be a frightening prospect. This study was aimed to check whether prescription of analgesics is necessary or not after simple extraction of the mandibular third molars. Material and methods. Seventy-six dental outpatients undergoing uncomplicated extraction of both mandibular third molars teeth served as subjects. After extraction on the first side, patients received either naproxen sodium 550 mg orally or a placebo. The order of the drugs was reversed during extraction on side two. The postoperative pain was scored with a six-point category rating scala. The obtained data were analyzed with Mann-Whitney U-test. Results. The sum of the pain intensity for hours 2 through 8 was less for the group that received sodium naproxen. For hours 8-24, the sum of the pain intensity was less for the placebo group but this difference was not statistically different. Conclusion. This study shows that uncomplicated tooth extraction did not cause a significant postoperative pain and there was no need to prescribe analgesics for such cases.

Tozoglu Sinan

2009-01-01

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Bacteremia after plate removal and tooth extraction.  

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Our aim was to investigate the occurrence of bacteremia associated with removal of a semirigid osteosynthesis plate and an adjacent third molar. Ten patients with fixed mandibular angle fracture were bacteriologically sampled from the second molar's distal gingival pocket, from the third molar's extraction socket and from the osteosynthesis plate. Blood samples from the ante-cubital vein were taken 10 times until 30 min postoperatively. Established culture, isolation and identification methods for the bacterial species were used. Bacteremia was detected in 60% of the subjects, most frequently 1.5 min after removal of the plate (20%) and 1.5 and 5 min after extraction of the tooth (20%), but also 10 min (10%) and 30 min (10%) postoperatively. 13 different bacterial species or groups were isolated, mean 2.5 +/- 1.9 per bacteremia-positive subject. The majority (85%) were anaerobes with Actinomyces, Campylobacter and Lactobacillus species predominating. In all the blood culture-positive cases the corresponding species was also recovered from one or more of the oral samples. These results show that oral surgical procedures are associated with a high frequency of longstanding anaerobic bacteremia, which could be harmful in patients at risk. PMID:15145038

Rajasuo, A; Nyfors, S; Kanervo, A; Jousimies-Somer, H; Lindqvist, C; Suuronen, R

2004-06-01

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Intra-oral PTH Administration Promotes Tooth Extraction Socket Healing  

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Intermittent parathyroid hormone (PTH) administration increases systemic and craniofacial bone mass. However, the effect of PTH therapy on healing of tooth extraction sites is unknown. The aims of this study were to determine the effect of PTH therapy on tooth extraction socket healing and to examine whether PTH intra-oral injection promotes healing. The mandibular first molars were extracted in rats, and subcutaneous PTH was administered intermittently for 7, 14, and 28 days. In a second stu...

Kuroshima, S.; Kovacic, B. L.; Kozloff, K. M.; Mccauley, L. K.; Yamashita, J.

2013-01-01

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Alveolar process reconstruction after tooth extraction by orthodontic indications  

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Full Text Available The objective of the study is to determine indications for alveolar bone reconstruction after tooth extraction according to orthodontic indications. Material and methods. 62 patients (first maturity level with dental arch asymmetry due to loss of a premolar on one side of the mouth were examined and treated. Frontal-diagonal coefficient of the dental arch was used to determine the correlation between tooth size and dental arch parameters. Results. It has been demonstrated that changes of the alveolar ridge following the extraction of the first premolars in patients of the experimental group were less significant as compared with the controls. Conclusion. It is reasonable to apply this method simultaneously with the removal of a tooth for orthodontic indications or when the alveolar ridge in the post-extraction socket leaves insufficient bone volume.

Kovalev ?.?.

2013-09-01

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The role of traditional healers in tooth extractions in Lekie Division, Cameroon  

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Abstract Background The extraction of the teeth by traditional healers in Cameroon is an established cultural practice in the central region of the Cameroon. Traditional healers (TH) use herbs and crude un-sterilized instruments and tools for the tooth extraction procedure. The present study investigates the knowledge and practices of traditional healers regarding tooth extraction and the management of its complications. Methods A cross sectional design utilizing semi-structured questionnaire...

Naidoo Sudeshni; Agbor Ashu M; Mbia Awono M

2011-01-01

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Contour changes in human alveolar bone following tooth extraction of the maxillary central incisor  

OpenAIRE

The purpose of this study was to apply cone-beam computed tomography (CBCT) to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original morphological evidence for aesthetic implant treatment in the maxillary anterior area. Forty patients were recruited into the study. Each patient had two CBCT scans (CBCT I and CBCT II), one taken before and one taken three months after tooth extraction of maxillary central incisor (test to...

Li, Bei; Wang, Yao

2014-01-01

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Application of coenzyme Q10 for accelerating soft tissue wound healing after tooth extraction in rats.  

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Accelerating wound healing after tooth extraction is beneficial in dental treatment. Application of antioxidants, such as reduced coenzyme Q10 (rCoQ10), may promote wound healing after tooth extraction. In this study, we examined the effects of topical application of rCoQ10 on wound healing after tooth extraction in rats. After maxillary first molars were extracted, male Fischer 344 rats (8 weeks old) (n = 27) received topical application of ointment containing 5% rCoQ10 (experimental group) or control ointment (control group) to the sockets for 3 or 8 days (n = 6-7/group). At 3 days after extraction, the experimental group showed higher collagen density and lower numbers of polymorphonuclear leukocytes in the upper part of socket, as compared to the control group (p socket, but that rCoQ10 has a limited effect on bone remodeling in rats. PMID:25514392

Yoneda, Toshiki; Tomofuji, Takaaki; Kawabata, Yuya; Ekuni, Daisuke; Azuma, Tetsuji; Kataoka, Kota; Kunitomo, Muneyoshi; Morita, Manabu

2014-12-01

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Effect of tooth extraction on stomatitis in cats: 95 cases (2000-2013).  

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Objective-To evaluate long-term response of cats with stomatitis to tooth extraction. Design-Retrospective case series. Animals-95 cats with stomatitis. Procedures-Medical records of cats with stomatitis that was treated with tooth extraction during a 14-year period were reviewed. Demographic information and diagnostic results were recorded as well as surgical procedure, including full-mouth extraction (FME) versus partial-mouth extraction (PME), and specifics of medical management. Patients were categorized according to response to treatment. Results-Median postoperative follow-up time was 231 days (range, 33 to 2,655 days). Of 95 cats, 6 (6.3%) had no improvement and 25 (26.3%) had little improvement in stomatitis following tooth extraction and extended medical management (EMM). Following tooth extraction, 37 (39.0%) cats had substantial clinical improvement and 27 (28.4%) cats had complete resolution of stomatitis; of these 64 cats, 44 (68.8%) required EMM for a finite period to achieve positive outcomes. Extent of tooth extraction (PME vs FME) was not associated with overall response to treatment. At initial recheck examination, a better long-term response to tooth extraction was observed in patients with resolution of abnormal behavior (OR, 7.2), decrease in oral inflammation (OR, 3.5), and lack of need for follow-up medical management with antimicrobials (OR, 3.7). Conclusions and Clinical Relevance-Extraction of teeth in areas of oral inflammation provided substantial improvement or complete resolution of stomatitis in more than two-thirds of affected cats. Full-mouth extraction did not appear to provide additional benefit over PME. Most cats with stomatitis may require EMM to achieve substantial clinical improvement or complete resolution. (J Am Vet Med Assoc 2015;246:654-660). PMID:25719848

Jennings, Michael W; Lewis, John R; Soltero-Rivera, Maria M; Brown, Dorothy C; Reiter, Alexander M

2015-03-15

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Application of Coenzyme Q10 for Accelerating Soft Tissue Wound Healing after Tooth Extraction in Rats  

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Full Text Available Accelerating wound healing after tooth extraction is beneficial in dental treatment. Application of antioxidants, such as reduced coenzyme Q10 (rCoQ10, may promote wound healing after tooth extraction. In this study, we examined the effects of topical application of rCoQ10 on wound healing after tooth extraction in rats. After maxillary first molars were extracted, male Fischer 344 rats (8 weeks old (n = 27 received topical application of ointment containing 5% rCoQ10 (experimental group or control ointment (control group to the sockets for 3 or 8 days (n = 6–7/group. At 3 days after extraction, the experimental group showed higher collagen density and lower numbers of polymorphonuclear leukocytes in the upper part of socket, as compared to the control group (p < 0.05. Gene expression of interleukin-1?, tumor necrosis factor-? and nuclear factor-?B were also lower in the experimental group than in the control group (p < 0.05. At 8 days after tooth extraction, there were no significant differences in collagen density, number of polymorphonuclear leukocytes and bone fill between the groups. Our results suggest that topical application of rCoQ10 promotes wound healing in the soft tissue of the alveolar socket, but that rCoQ10 has a limited effect on bone remodeling in rats.

Toshiki Yoneda

2014-12-01

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Protein synthesis in wound after tooth extraction in pancreatectomized diabetic rats.  

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The incorporation of alanine C14 in protein synthesis was analyzed in recently formed alveolar tissue after tooth extraction in partially-pancreatectomized diabetic rats. The incorporation of alanine C14 was higher in diabetic animals than in treated diabetic and control groups. The results can be explained by a delay in bone tissue repair. PMID:2135874

Grandini, S A; Brentegani, L G; Novaes, A B; Migliorini, R H

1990-01-01

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Effect of irradiation on wound healing after tooth extraction in the rachitic rats  

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To observe the histopathological changes following irradiation on the wound healing after tooth extraction in the rachitic rats. In order to carry out this study, the rats were divided into four groups: Group 1 (normal diet/non-irradiation group), Group 2 (normal diet/irradiation group), Group 3 (rachitogenic diet/non-irradiation group), and Group 4 (rachitogenic diet/irradiation group). Rachitic changes were induced with rachitogenic diet No. 2 (high calcium, low phosphorus, and Vitamin D deficient diet) for 5 weeks. After the extraction of both maxillary first molars of the rats in Group 2 and 4, the head and neck of the rats were irradiated with single absorbed dose of 10 Gy. The rats were sacrificed at the 1st, 5th, 10th, and 15th day after tooth extraction. The specimens including the extraction wound were sectioned, stained with the hematoxylin-eosin and Masson's trichrome method and examined under the light microscope. In the Group 2, the amount of newly formed bone trabeculae on the periphery of extraction socket and osteoblastic activity were reduced. In the Group 3, epithelial fusion was not revealed on the 5th day after toothe extraction and growth rate of osteoid formation was reduced. In the Group 4, necrotized tissue at the outer surface of extraction socket and destructive changes on the alveolar bones were noted on the 10th day. Epithelial fusion was not revealed and large amounts of osteoclast were noted on alveolar bone on the 15th day. The healing pveolar bone on the 15th day. The healing process of wound after tooth extraction was retarded by irradiation and especially in the rachitic rats.

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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

2014-10-01

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

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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. PMID:12238809

Yugoshi, Luciana Ibara; Sala, Miguel Angel; Brentegani, Luiz Guilherme; Lamano Carvalho, Teresa Lúcia

2002-01-01

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A study on the effects of electron beam irradiation on tooth extraction wound healing in rats  

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The wound of the upper jaw 3 days after the first molar tooth extraction in female rats was exposed to 1,500 rads (Group 2) and 2,000 rads (Group 3) of the 10 MeV electron beams, and its pathohistological changes were compared with those of rats with the tooth extraction alone (control group). In the control group, the tooth extraction wound was covered with epithelium 10 days later and new bones were formed 17 days later. Wound healing with the epithelium was seen in all irradiated rats 24 days later. The formation of the new teeth was seen 24 days later in the Group 2 and 38 days later in Group 3. Cell infiltration under the epithelial layers was still observed in some of the Group 3, although the wound was covered with epithelium, and the new bone covering the extraction wound was formed 38 days later. Healing was prolonged in Group 3, as compared with that in Group 2. (Namekawa, K.)

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Should retention of a tooth be an important goal of dentistry? How do you decide whether to retain and restore a tooth requiring endodontic treatment or to extract and if possible replace the tooth?  

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Whether a questionable tooth should be treated endodontically or extracted, is still a dilemma clinicians encounter every day. With advances in technology such as implantology, deciding whether or not to save a tooth is still not clear. Local site-specific factors and patient-related factors that may affect the longevity of a particular tooth should be considered in preparing the treatment plan. Long-term success rates for root canal therapy and implant-supported crowns demonstrate similar outcomes. A choice between these alone is not sufficient in the decision-making process. Only following a systematic evaluation of the reasons for and against tooth retention as directed by each individual case, can the best option be decided. PMID:25850364

Zachar, Jessica J

2015-04-01

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Contour changes in human alveolar bone following tooth extraction of the maxillary central incisor.  

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The purpose of this study was to apply cone-beam computed tomography (CBCT) to observe contour changes in human alveolar bone after tooth extraction of the maxillary central incisor and to provide original morphological evidence for aesthetic implant treatment in the maxillary anterior area. Forty patients were recruited into the study. Each patient had two CBCT scans (CBCT I and CBCT II), one taken before and one taken three months after tooth extraction of maxillary central incisor (test tooth T). A fixed anatomic reference point was used to orient the starting axial slice of the two scans. On three CBCT I axial slices, which represented the deep, middle, and shallow layers of the socket, labial and palatal alveolar bone widths of T were measured. The number of sagittal slices from the start point to the pulp centre of T was recorded. On three CBCT II axial slices, the pulp centres of extracted T were oriented according to the number of moved sagittal slices recorded in CBCT I. Labial and palatal alveolar bone widths at the oriented sites were measured. On the CBCT I axial slice which represented the middle layer of the socket, sagittal slices were reconstructed. Relevant distances of T on the sagittal slice were measured, as were the alveolar bone width and tooth length of the opposite central incisor. On the CBCT II axial slice, which represented the middle layer of the socket, relevant distances recorded in CBCT I were transferred on the sagittal slice. The height reduction of alveolar bone on labial and palatal sides was measured, as were the alveolar bone width and tooth length of the opposite central incisor at the oriented site. Intraobserver reliability assessed by intraclass correlation coefficients (ICCs) was high. Paired sample t-tests were performed. The alveolar bone width and tooth length of the opposite central incisor showed no statistical differences (Plabial alveolar bone widths of T at the deep, middle, and shallow layers all showed statistical differences. However, no palatal alveolar bone widths showed any statistical differences. The width reduction of alveolar bone was 1.2, 1.6, and 2.7 mm at the deep, middle, and shallow layers, respectively. The height reduction of alveolar bone on labial and palatal sides of T both showed statistical differences, which was 1.9 and 1.1 mm, respectively. PMID:25471836

Li, Bei; Wang, Yao

2014-12-01

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

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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 ?mol/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) (P0.05). Conclusion In conclusion, the findings of this study suggest that CAPE can significantly improve tooth socket healing. PMID:25364232

Günay, Ahmet; Arpa?, Osman Fatih; Atilgan, Serhat; Yaman, Ferhan; Atalay, Yusuf; Acikan, ?zzet

2014-01-01

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Tooth Extraction  

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... the jawbone that gives feeling to your lower jaw, lower teeth, lower lip and chin. This nerve is called the inferior alveolar nerve. Any infections, tumors or bone disease that may be present Some doctors prescribe antibiotics ...

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

International Nuclear Information System (INIS)

We examined effects of local and whole body irradiation before tooth extraction on appearance and differentiation of osteoclasts in the alveolar bone of rat maxillary first molars. Wistar rats weighting 100 g were divided into three groups: non-irradiation group, local irradiation group, and whole body irradiation group. In the local irradiation group, a field made with lead blocks was placed over the maxillary left first molar tooth. In the whole body irradiation group, the animals were irradiated in cages. Both groups were irradiated at 8 Gy. The number of osteoclasts around the interradicular alveolar bone showed chronological changes common to non-irradiated and irradiated animals. Several osteoclasts appeared one day after tooth extraction, and the maximal peak was observed 3 days after extraction. Local irradiation had no difference from non-irradiated controls. In animals receiving whole body irradiation, tooth extraction one day after irradiation caused smaller number of osteoclasts than that 7 day after irradiation during the experimental period. Whole body-irradiated rats had small osteoclasts with only a few nuclei and narrow resorption lacunae, indicating deficiency of radioresistant osteoclast precursor cells. Injection of intact bone marrow cells to whole body-irradiated animals immediately after tooth extraction recovered to some content the number of osteoclasts. These findings suggest that bone resorption in the wound healing of alveolar socket requirhe wound healing of alveolar socket requires radioresistant, postmitotic osteoclast precursor cells from hematopoietic organs, but not from local sources around the alveolar socket, at the initial phase of wound healing. (author)

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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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Perioperative management of tooth extractions for a patient with hereditary angioedema.  

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Hereditary angioedema (HAE) is a rare genetic disorder that causes a deficiency in or dysfunction of C1 esterase inhibitor (C1-INH) and is clinically characterized by sudden and recurrent attacks of angioedema. Although almost any part of the body can be affected, HAE is of greatest concern and can be life-threatening when the upper airway is involved, particularly the larynx (laryngeal attack). HAE attacks can be triggered by physical or psychological stress or can arise spontaneously without any apparent trigger. Dental treatments and routine oral surgical procedures, such as tooth extraction, abound with factors that can trigger an attack of HAE. Indeed, several cases of death resulting from HAE attacks have been reported after such procedures. Therefore, patients with HAE are of special concern in dentistry and require precautionary preparations before treatment. This report describes the successful management of tooth extractions in a patient with HAE who was at high risk of an HAE-induced laryngeal attack. PMID:25308409

Sanuki, Takuro; Watanabe, Toshihiro; Kurata, Shinji; Ayuse, Takao

2014-12-01

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A preliminary study of local administration of dexamethasone after tooth extraction: Better preservation of residual alveolar ridge?  

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Full Text Available Background/Aim. It is important that the height of the edentulous alveolar ridge after tooth extraction remains at a reasonable acceptable level for as long as possible. The aim of this study was to report preliminary results of the clinical effect of local oral submucous administration of dexamethasone after tooth extractions in order to prepare alveolar supporting tissues for acceptance of removable dentures. Methods. In a total of 15 patients (11 partially and 4 completely edentulous the quantity of 0.25 mL to 0.5 mL of dexamethasone was injected bucally and orally in the region of the tooth socket after complicated extractions. Results. Healing of extraction wounds was uneventful in all the patients, without pain or local inflammation. Conclusion. Dexamethasone can be locally applied to oral tissues to prevent post-extraction inflammation and extensive resorption of the residual alveolar ridge. The obtained results are promising for patients undergoing classic prosthodontic rehabilitation soon after tooth extraction, demonstrating that there are no adverse effects after local oral corticosteroids administration. [Projekat Ministarstva nauke Republike Srbije, br. 175021

Pošti? Sr?an D.

2014-01-01

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Morphological studies on the healing process of tooth extraction wounds in whole body irradiated rats  

International Nuclear Information System (INIS)

The present studies were performed to investigate the healing process of the tooth extraction wound in whole body irradiated rats and to clarify the effect of irradiation on bone metabolism. One hundred and seven Wistar rats of about 100 g body weight were used and divided into 3 groups. Whole body irradiated rats were given single exposure with a dose of 8 Gy. The region of the left upper molars of local irradiated rats as controls, was exposed to 8 Gy. On the 7th day after irradiation, the left upper first molar of each rat was extracted. The rats were sacrificed at intervals of 1 to 14 days after extraction. Non-irradiated rats were sacrificed at the same intervals after extraction. The maxillary bone including the extraction wound was evaluated, histologically, histometrically and ultrastructurally. From the histological and histometrical findings, the difference of the healing process between non-irradiated rats and locally irradiated rats is not significant. In whole body irradiated rats, the healing process especially in the socket was disturbed. The osteoblastic new bone formation following production of granulation tissue was interfered with. Ultrastructurally, the cytoplasmic organellae were poorly developed in the osteoblast and osteoid formation was reduced in the socket. But periosteal new bone formation was the same as that of the locally irradiated rats. In whole body irradiated rats, the osteoclasts in the interradicular alveolar bone were decreased anrradicular alveolar bone were decreased and have smaller nuclei, compared with non-irradiated and locally irradiated rats. Histometrically, the amount of bone loss was decreased in whole body irradiated rats. Ultrastructurally, the cyoplasmic organellae and ruffled border were poorly developed in the osteoclasts of whole body irradiated rats. The findings suggested that irradiation induced cytological changes not only in osteoblasts but in osteoclasts and these changes resulted in the delayed healing of extraction wound. (author) 106 refs

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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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Alveolar ridge preservation of an extraction socket using autogenous tooth bone graft material for implant site development: prospective case series  

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This case series evaluated the clinical efficacy of autogenous tooth bone graft material (AutoBT) in alveolar ridge preservation of an extraction socket. Thirteen patients who received extraction socket graft using AutoBT followed by delayed implant placements from Nov. 2008 to Aug. 2010 were evaluated. A total of fifteen implants were placed. The primary and secondary stability of the placed implants were an average of 58 ISQ and 77.9 ISQ, respectively. The average amount of crestal bone loss around the implant was 0.05 mm during an average of 22.5 months (from 12 to 34 months) of functional loading. Newly formed tissues were evident from the 3-month specimen. Within the limitations of this case, autogenous tooth bone graft material can be a favorable bone substitute for extraction socket graft due to its good bone remodeling and osteoconductivity. PMID:25551013

Yun, Pil-Young; Um, In-Woong; Lee, Hyo-Jung; Yi, Yang-Jin; Bae, Ji-Hyun; Lee, Junho

2014-01-01

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Treatment of oroantral communications after tooth extraction. Is drainage into the nose necessary or not?  

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Seventy-six patients with oroantral communications after tooth extraction and chronic maxillary sinusitis were treated as follows: bacterial cultures were taken in all of them and maxillary sinuses were irrigated with an antibiotic from the cephalosporin group. Then, in 36 patients, drainage using the Caldwell Luc procedure was performed, including a naso-antral window. In all patients operations were completed by closing oroantral communications with flaps of the mucosa of the alveolar process close to the fistula. Antibiotics according to antibiogram were administered to all patients at least 10 days after surgery. Retrospective comparison between the results obtained in the first group and those in the second group 1, 3 and 6 months after operation was based on objective findings (condition of the oroantral communication, maxillary sinusitis), side effects (pain, numbness of the operated area, headache) and control radiographs (clear maxillary sinus or with mucosal thickening). The study suggests that transnasal drainage is not required in maxillary sinus surgery and in the closure of oroantral communications. Equally good results are achieved by treating with antibiotics and without drainage of the maxillary sinus into the nose. PMID:9870631

Car, M; Jureti?, M

1998-11-01

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An innovative approach to chair side provisional replacement of an extracted anterior tooth with Fiber Reinforced Ribbon Composite for space maintenance  

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Full Text Available An immediate replacement of an extracted anterior tooth may contribute to patients comfort, treatment acceptance and expectations of future treatment. However, fabrication of custom made restoration in the anterior region of the mouth through a removable or fixed may result in an esthetic compromise for patients during fabrication period. Chair side tooth replacement is an excellent short term option and one of the method is application of fiber reinforced composite resin technology. Though this method is used for reinforcing permanent tooth its use for primary teeth has not been reported. This article presents an innovative, affordable chair side procedure in which ribbon multipurpose bondable reinforcement ribbon is used to replace a single extracted tooth using patients own tooth.

Srinivas N CH

2011-04-01

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Dry Socket following Tooth Extraction in an Iranian Dental Center: Incidence and Risk Factors Dry Socket following Tooth Extraction in an Iranian Dental Center: Incidence and Risk Factors  

OpenAIRE

Introduction: Dry Socket (DS) is a common post-surgical complication following extraction of permanent teeth. Various risk factors has been mentioned for this complication including gender, age, amount of trauma during extraction, difficulty of extraction, inappropriate irrigation, infection, smoking, and oral contraceptive use. The aim of this study was to evaluate the incidence of DS among permanent teeth extraction in an Iranian Oral and Maxillofacial clinic and also to identify risk fac...

Majid Eshghpour; Amir Moradi; Amir Hossein Nejat

2013-01-01

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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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Oral health-related quality of life following non-surgical (routine) tooth extraction: A pilot study  

Science.gov (United States)

Aim: The study was designed to explore the changes in oral health-related quality of life (QoL) in the immediate postoperative period following routine (non-surgical) dental extraction. Setting and Design: A prospective study carried out at the Oral and Maxillofacial Surgery clinic of the Lagos University Teaching Hospital, Nigeria. Materials and Methods: Subjects attending who required non-surgical removal of one or two teeth under local anesthesia were included in the study. A baseline QoL questionnaire (oral health impact profile-14 [OHIP-14]) was filled by each patient just before surgery, and only those who were considered to have their QoL “not affected” (total score 14 or less) were included in the study. After the extraction, each subject was given a modified form of “health related QoL” [OHIP-14]-instrument to be completed by the 3rd day-after surgery, and were given the opportunity to review the questionnaire on the 7th day postoperative review. Results: Total OHIP-14 scores ranged between 14 and 48 (mean ± SD, 26.2 ± 8.3). Majority of the subjects (60%) reported, “a little affected.” Only few subjects (5.8%) reported, “not at all affected,” and about 32% reported, “quite a lot.” Summation of OHIP-14 scores revealed that QoL was “affected” in 41 subjects (34.2%) and “not affected” in 79 subjects (65.8%). More than 30% of subjects reported that their ability to chew, ability to open the mouth and enjoyment of food were affected following tooth extraction. Few subjects (14-34%) reported deterioration in their speech and less than 20% of subjects reported that change in their appearance was “affected.” Only few subjects (12.5-15.1%) reported sleep and duty impairment. Thirty-percent of subjects reported their inability to keep social activities, and 41% were not able to continue with their favorite sports and hobbies. Multiple regression analysis revealed no significant association between age, sex, indications for extraction, duration of extraction, intra-operative complications, and deterioration in QoL (P < 0.05). Consumption of analgesics beyond postoperative day 1 (POD1) was more common in subjects with socket healing complications than those without (P = 0.000). About 33% of subjects reported, “inability to work” (1-3 days). Conclusion: About a third of subjects experienced significant deterioration in QoL. The most affected domains were eating/diet variation and speech variation. Therefore, patients should be informed of possible deterioration in their QoL following non-surgical tooth extraction. PMID:23633803

Adeyemo, Wasiu L.; Taiwo, Olanrewaju A.; Oderinu, Olabisi H.; Adeyemi, Moshood F.; Ladeinde, Akinola L.; Ogunlewe, Mobolanle O.

2012-01-01

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EXTERNAL CAROTID ARTERY PSEUDOANEURYSM AND INTERNAL JUGULER VEIN THROMBOSIS FOLLOWING TOOTH EXTRACTION IN A CASE OF BEHÇET’S DISEASE  

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Full Text Available Behçet’s disease is a multisystemic inflammatory disease of unknown cause, presenting with vasculitis. Complications such as pseudoaneurysm or thrombosis may be seen due to major vein and artery involvement in addition to vasculitis causing clinical manifestations. Major artery complications are seen most commonly in the aorta, pulmonary, femoral, subclavian or carotid artery. The involvement of an extracranial artery, particularly the external carotid artery is uncommon in the literature. In our case, the clinical and radiologic findings of a young male Behçet patient with an external carotid artery pseudoaneurysm and internal jugular vein thrombosis following tooth extraction is presented together with the relevant literature. No such complication of Behçet’s disease following a dental manipulation has previously been reported in the literature. .

Arda Kayhan

2009-01-01

35

A histometric study in rats of the effect of the calcium antagonist amlodipine on bone healing after tooth extraction.  

Science.gov (United States)

The purpose was to investigate whether amlodipine, a second-generation calcium antagonist used for the treatment of hypertension and angina, interferes with healing of rat alveolar bone. A progressive increase in volume density of new bone filling the socket was quantified by a histometric differential point-counting method 7-42 days after tooth extraction. The results showed a 20-30% decrease in bone volume fraction in the alveolus of amlodipine-treated animals from 7 days on, in addition to a higher (7-35%) volume fraction of connective tissue and a tendency toward an increase in the volume fraction of persisting coagulum. If confirmed in humans, the knowledge of a deleterious effect of Ca-channel blockers in hindering alveolar bone healing would be important in planning oral operations involving bone tissue, including those for device implantation. PMID:11269871

Teófilo, J M; Brentegani, L G; Carvalho, T L

2001-04-01

36

X radiation effects on the wound healing process after tooth extraction. Histological study in rats  

International Nuclear Information System (INIS)

The X radiation effects on the wound healing process after teeth extractions are studied histologically. Albino rats are employed. After their right upper incisors were extracted, they were divided into groups of 20 animals each. With exception of the group I (control), 24 hours after teeth extractions the groups II, III and IV received X radiation, respectively, in the dosage of 75,125 and 175 R. The rats were sacrificed in group of 4, at 3, 6, 9,15 and 21 postoperative days and a histological study is done. (M.A.C.)

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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

38

Tooth ankylosis: Orthodontic implications.  

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Full Text Available Tooth ankylosis is a condition, which may lead to an occlusal abnormality. The etiology is unknown although different and often contradicting opinions have been presented. It prevails on primary teeth, characterized by progressive infraocclusion. Ankylosis on permanent teeth is less frequent and is associated with trauma and impaction. Management of the affected tooth ranges from simple observation to extraction. A protocol assisting in the proper diagnosis and treatment is presented.

P. Panos

2003-01-01

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Esthetic evaluation of single-tooth Morse taper connection implants placed in fresh extraction sockets or healed sites.  

Science.gov (United States)

The aim of this study was to compare the esthetic outcome of single implants placed in fresh extraction sockets with those placed in fully healed sites of the anterior maxilla. This retrospective study was based on data from patients treated with single-tooth Morse taper connection implants placed in fresh extraction sockets and in fully healed sites of the anterior maxilla. Only single implant treatments were considered with both neighboring teeth present. Additional prerequisites for immediate implant treatment were intact socket walls and a thick gingival biotype. The esthetic outcome was objectively rated using the pink esthetic/white esthetic score (PES/WES). The Mann-Whitney U test was used to compare the PES and the WES between the 2 groups. Twenty-two patients received an immediate implant, and 18 patients had conventional implant surgery. The mean follow-up was 31.09 months (SD 5.57; range 24-46) and 34.44 months (SD 7.10; range 24-48) for immediately and conventionally inserted implants, respectively. No implants were lost. All implants fulfilled the success criteria. The mean PES/WES was 14.50 (SD 2.52; range 9-19) and 15.61 (SD 3.20; range 8-20) for immediately and conventionally placed implants, respectively. Immediate implants had a mean PES of 7.45 (SD 1.62; range 4-10) and a mean WES of 7.04 (SD 1.29; range 5-10). Conventional implants had a mean PES of 7.83 (SD 1.58; range 4-10) and a mean WES of 7.77 (SD 1.66; range 4-10). The difference between the 2 groups was not significant. Immediate and conventional single implant treatment yielded comparable esthetic outcomes. PMID:22126700

Mangano, Francesco G; Mangano, Carlo; Ricci, Massimiliano; Sammons, Rachel L; Shibli, Jamil A; Piattelli, Adriano

2013-04-01

40

Calcium dynamics in the healing of tooth extraction sockets in mice evaluated using 45Ca-autoradiography and Electron Probe Micro Analysis  

International Nuclear Information System (INIS)

The calcium distribution in tooth extraction sockets of mice was examined using 45-Calcium autoradiography (ARG) and Electron Probe Micro Analysis (EPMA). Mice were divided into 8 groups (n=8) according to the number of days (1, 2, 3, 4, 5, 7, 10, 20 respectively) after extraction. Frozen sections were taken from mice on each experimental day after injection of 45-Calcium (RI). The process of formation of new bone was observed using ARG. An ultimate analysis was performed by EPMA. Histological analysis was performed with toluidine blue- and alizarin red S-staining. In toluidine blue-staining, an osteoblast was found along the socket wall at 4 days and non-calcified periodontal ligament was recognized until 5 days after extraction. In alizarin red S-staining, new bone was recognized separated from the socket wall at 4 days after extraction. 45Ca-labeling was detected strongly in the periosteum of the mandible, the surface of cement and periodontal ligament in control animals. 45Ca-labeling was moved from the bottom to the top of the tooth extraction socket during the period from 1 to 5 days after extraction, but in the periodontal ligament lower than in the granulation tissue. 45Ca-labeling was detected in the socket at 7, 10 and 20 days. At 4 days, calcium phosphate was observed in the central portion of the socket using EPMA. 45Ca-labeling showed deposition of calcium phosphate for alveolar bone and new bone. These results alveolar bone and new bone. These results suggest that the granulation tissue may be involved in the initial calcification in the tooth extraction socket and lead to the formation of new bone in it. (author)

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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

42

Sobredentadura: alternativa terapéutica para disminuir las extracciones dentarias / Overdenture: therapeutic alternative to decrease tooth extractions  

Scientific Electronic Library Online (English)

Full Text Available Se describe el caso clínico de una paciente de 45 años de edad, atendida en la Clínica Estomatológica Docente "José Luis Tassende" de Santiago de Cuba porque refería que en innumerables ocasiones se le fracturaban los dientes artificiales de la prótesis y la porción coronaria de la espiga del incisi [...] vo central superior derecho; también presentaba algunos dientes remanentes con facetas de desgastes en las caras palatinas, incisales y vestibulares, por lo cual se le realizó una prótesis parcial metálica (superior e inferior), con sobredentadura sobre dientes naturales. Con el proceder aplicado se evitaron las extracciones dentarias y se logró una adecuada rehabilitación estética y funcional Abstract in english The case report of a 45 year-old patient, assisted in "José Luis Tassende" Stomatological Clinic from Santiago de Cuba is described. She complained of fractures in countless occasions of the artificial teeth from her denture and the coronary portion of the pin of the central right superior incisor t [...] ooth; she also presented some residual teeth with facets of waste in the palatine, incisal and vestibular faces, reason why a metallic partial prosthesis (superior and inferior), with overdenture on her natural teeth was made. With this procedure, the teeth extractions were avoided and an appropriate aesthetic and functional rehabilitation was achieved

Mario, Castañeda Deroncelé.

1611-16-01

43

Porous magnesium/PLGA composite scaffolds for enhanced bone regeneration following tooth extraction.  

Science.gov (United States)

Sixty percent of implant-supported dental prostheses require bone grafting to enhance bone quantity and quality prior to implant placement. We have developed a metallic magnesium particle/PLGA composite scaffold to overcome the limitations of currently used dental bone grafting materials. This is the first report of porous metallic magnesium/PLGA scaffolds synthesized using a solvent casting, salt leaching method. We found that incorporation of varying amounts of magnesium into the PLGA scaffolds increased the compressive strength and modulus, as well as provided a porous structure suitable for cell infiltration, as measured by mercury intrusion porosimetry. Additionally, combining basic-degrading magnesium with acidic-degrading PLGA led to an overall pH buffering effect and long-term release of magnesium over the course of a 10-week degradation assay, as measured with inductively coupled plasma-atomic emission spectroscopy. Using an indirect proliferation assay adapted from ISO 10993:5, it was found that extracts of medium from degrading magnesium/PLGA scaffolds increased bone marrow stromal cell proliferation in vitro, a phenomenon observed by other groups investigating magnesium's impact on cells. Finally, magnesium/PLGA scaffold biocompatibility was assessed in a canine socket preservation model. Micro-computed tomography and histological analysis showed the magnesium/PLGA scaffolds to be safer and more effective at preserving bone height than empty controls. Three-dimensional magnesium/PLGA composite scaffolds show promise for dental socket preservation and also, potentially, orthopedic bone regeneration. These scaffolds could decrease inflammation observed with clinically used PLGA devices, as well as enhance osteogenesis, as observed with previously studied magnesium devices. PMID:25234156

Brown, Andrew; Zaky, Samer; Ray, Herbert; Sfeir, Charles

2015-01-01

44

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 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

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Histometric study of socket healing after tooth extraction in rats treated with diclofenac / Estudo histométrico do reparo alveolar após extração dental em ratos tratados com diclofenaco  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O objetivo do presente trabalho foi investigar se a administração de diclofenaco interfere no processo de reparo alveolar em ratos. Foram utilizados 42 ratos Wistar, dos quais 21 receberam 10mg/kg/dia de diclofenaco e o restante solução salina. Os animais foram submetidos a extração dos incisivos su [...] periores direito, e sacrificados 7, 14 e 21 dias após a avulsão dental. A formação progressiva de osso e a redução do volume de coágulo sangüíneo e tecido conjuntivo no período de 1 a 3 semanas após a extração dental foram quantificadas através do método histométrico de contagem de pontos. O tratamento com o diclofenaco causou significante atraso na neo-formação óssea, associado a um atraso na organização e remissão do coágulo sangüíneo. Abstract in english 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.

Luciana Ibara, Yugoshi; Miguel Angel, Sala; Luiz Guilherme, Brentegani; Teresa Lúcia Lamano, Carvalho.

46

Attractancy toOryzaephilus surinamensis (L.), saw-toothed grain beetle, of extracts of carobs, some triglycerides, and related compounds.  

Science.gov (United States)

A laboratory method has been devised for testing the attractancy of vapors to adultOryzaephilus surinamensis (L.). Of four solvent extracts prepared from pods of the carob tree [Ceratonia siliqua (L.)], all attractedO. surinamensis, but the least polar extract was the most active. Subdivision of extracts yielded a series of fractions, the most attractive of which contained a mixture of triglycerides with three or more double bonds per molecule. Twelve authentic triglycerides, either synthesized or purchased, elicited responses ranging from high to very low attractancy in a way which appeared to be related to the number, position, and geometrical shape of the double bonds in the molecules. By studying the response of the insects to five glyceride acids, three aldehydes, and three volatile fatty acids, it has been shown that it may be possible to explain the attractancy attributed to the triglycerides, which are involatile, in terms of the response to their volatile breakdown products. PMID:24407405

O'Donnell, M J; Chambers, J; McFarland, S M

1983-03-01

47

[Vivisection studies on the effects of unilateral tooth extraction on growth of the skull amd masticatory musculature (author's transl)].  

Science.gov (United States)

Following up on the 1st part of this cycle of publications, the 2nd Bulletin deals with investigations on upper and lower jaw growth in the Vietnamese belly pig after extracting all teeth as they appeared in the right half of the jaw. The results showed characteristic changes on the side of the extraction compared with the skull on the other side. They also show clearly that the effects of unilateral loss of teeth on the development of the bony part of the chewing apparatus are very local. This is made evident by analysis distances measured for the 3rd and 4th upper jaw widths and the 2nd vertical height of the bottom jaw. In contrast to other authors, we found no changes in the longitudinal and lateral development of the bottom jaw. Due to the slight degree of development of the alveolar process of the bottom jaw in the region of the 1st permanent molar, a significant reduction in surface area was found when removing the 2nd molars, which was performed usually at an early point, only in the group slaughtered after 12 months. PMID:7342794

Otto, B; Fanghänel, J; Schumacher, G H

1981-01-01

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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.

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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

50

Tooth discoloration induced by endodontic sealers.  

Science.gov (United States)

Endodontic therapy often results in discoloration of the tooth crown. The main causes are blood, necrotic pulp tissue, and endodontic materials. The staining potentials of various materials were examined in vitro by means of a visual method for tooth color determination. Extracted premolars were prepared, and the following sealers were introduced into the pulp cavities: Zinc oxide eugenol cement, Grossman's cement, AH26, Diaket, N2, Riebler's paste, Tubliseal, and Endomethasone. Before the sealers were applied, the original tooth colors were assessed on the external buccal tooth surfaces. Further color determinations were carried out at regular intervals up to 6 months after introduction of the sealers. Each material induced measurable tooth discoloration within 3 weeks. Riebler's paste caused the most severe discoloration while Diaket caused a mild stain. The other materials produced intermediate discolorations between those of Riebler and Diaket. PMID:3456145

van der Burgt, T P; Mullaney, T P; Plasschaert, A J

1986-01-01

51

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 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

52

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

53

Tooth-derived bone graft material  

OpenAIRE

With successful extraction of growth factors and bone morphogenic proteins (BMPs) from mammalian teeth, many researchers have supported development of a bone substitute using tooth-derived substances. Some studies have also expanded the potential use of teeth as a carrier for growth factors and stem cells. A broad overview of the published findings with regard to tooth-derived regenerative tissue engineering technique is outlined. Considering more than 100 published papers, our team has devel...

Kim, Young-kyun; Lee, Junho; Um, In-woong; Kim, Kyung-wook; Murata, Masaru; Akazawa, Toshiyuki; Mitsugi, Masaharu

2013-01-01

54

'Split posterior tooth': conservative clinical re-attachment.  

Science.gov (United States)

Trauma is the prime causative factor for fracture of teeth/dentition. Many procedural management options are followed successfully in relation to the anterior teeth. However, most posterior cases where the tooth is fractured have only limited options to pursue to save the tooth. Fractured teeth, whether they are vital/non-vital, are predominantly managed with surgical options. This paper discusses a conservative approach to reattaching a split posterior tooth. A split tooth situation is mostly an absolute indication for extraction, but the clinician may go in for extensive surgical procedures if he/she wishes to save it. The reattachment of the tooth can be successfully done and it can be put to function. This paper discusses how a split posterior tooth can be treated successfully, although depending on multiple factors. A full crown cemented after successful reattachment and root canal therapy would provide sufficient support in order for the tooth to heal. PMID:25080545

Abraham, Sathish; Chacko, Lisa Neelathil

2014-01-01

55

Towards tooth friendly soft drinks.  

Science.gov (United States)

Most soft drinks contain high concentration of simple carbohydrates and have a pH of 3 or even lower. Therefore, they are harmful for tooth structure. A tooth friendly soft drink (T.F.S.D) should have the following characteristics and elements; fluoride (approximately 1 ppm), casein phosphopeptide-amorphous calcium phosphate (2%), xylitol (4-6g/serving), tea polyphenols (2-4 mg/ml), cranberry extract (250 mg/ml of the flavonoids quercetin and myricetin), sugar free, pH close to 5.5 and super oxygenation (240,000 ppm) vs. carbonation. T.F.S.D can be packaged in a container which gaseous oxygen is dissolved in a liquid in the form of bubbles. However, looking at opportunities for so-called sophisticated soft drinks, T.F.S.D will be an example for a functional and health oriented soft drink. PMID:19570614

Kolahi, Jafar; Fazilati, Mohamad; Kadivar, Mahdi

2009-10-01

56

Life of a Tooth: A Visual Timeline  

Medline Plus

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

57

Replacing a Missing Tooth  

Science.gov (United States)

... and feel more natural than a removable partial denture. However, it does require grinding down the support teeth in order to crown them and connect them to the artificial tooth. Cleaning between the crowned teeth also becomes more difficult ...

58

Tooth Abfraction Lesions  

Science.gov (United States)

... Over time, this pressure can cause cracks and splits in the outer layer of your teeth. This ... layer below the enamel. Cementum covers the tooth root instead of enamel. Dentin may be exposed if ...

59

Seal Out Tooth Decay  

Science.gov (United States)

... Besides sealants, are there other ways to prevent tooth decay? How can I get dental sealants for my children? What are dental sealants? Sealants are thin, plastic coatings painted on the chewing surfaces of the back ...

60

Radiation dosimetry of tooth enamels with electron spin resonance (ESR)  

International Nuclear Information System (INIS)

Electron spin resonance (ESR) dosimetry method using tooth enamel was developed as to detect the minimum radiation dose of around 10 mGy. The main broad signal component must be subtracted from the ESR spectrum to get the signal induced by radiation. Dosimetry of residents close to Chernobyl reactor accident was made using eight tooth pieces with ESR. The obtained dose ranges from about 20 mSv to about 70 mSv including the effect of natural radiation and the dental X-rays. The ESR dosimetry system was developed to measure, the cumulative radiation dose in a tooth without extraction. (author)

61

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

62

An electron spin resonance system for in-vivo human tooth dosimetry  

International Nuclear Information System (INIS)

An electron spin resonance (ESR) dosimetry system for an in-vivo human tooth has been developed to measure, without extraction, the cumulative radiation dose in a tooth. The system consists of a TE102 cavity with an aperture at the end plate, a Nd-B-Fe (Neomax) oral magnet and a commercial ESR spectrometer. The front molar is attached to the aperture of the cavity to detect radicals created by radiation in the tooth enamel. Optimum dosimetry conditions were investigated using an extracted human tooth. (author)

63

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  

OpenAIRE

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 a...

Novaes Jr, Arthur B.; Patricia Garani Fernandes; Flávia Adelino Suaid; Marcio Fernando de Moraes Grisi; Sergio Luis Scombatti de Souza; Mario Taba Jr; Daniela Bazan Palioto; Valdir Antonio Muglia

2012-01-01

64

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

65

The effect of motor vehicle airbag deployment on tooth surfaces.  

Science.gov (United States)

Motor vehicle airbag technology is directed at the reduction of injury to drivers and passengers however a number of researchers have reported cases of injuries caused by airbags. Injuries to tooth surfaces, particularly tooth wear following the deployment of motor vehicle airbags, have never been studied. A review of the literature and clinical experience does not suggest tooth enamel abrasion to be a likely outcome following airbag deployment. This in vitro pilot study was conducted to assess the effect on tooth surfaces following the deployment of motor vehicle airbags, and in particular to attempt to reproduce the injuries claimed in a case report published in the Journal of Forensic Odonto- Stomatology in December 2007. A sample of extracted upper anterior teeth (n = 20) were analyzed using unaided visual observation, photographic and microscopic observation pre- and post- airbag deployment. Teeth were mounted on a fabricated head form (similar to those used in crash test dummies) using dental putty. The tests were performed using a modified airbag test rig with airbags deployed in 5 different positions relative to the head, with respect to distance and angulations. The result of the tests showed no changes to the teeth with unaided observation, macro photography or under the microscope. Tooth wear patterns described in the case report were not observed. Although accurate reproduction of an in vivo situation is not possible, this study has given some insight into the effects of motor vehicle airbag deployment, and suggests that significant tooth wear is an unlikely outcome from airbag deployment. PMID:22785097

Ashar, A; James, H; Higgins, D; Kaidonis, J; Anderson, R W G

2009-12-01

66

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

67

Partial tooth gear bearings  

Science.gov (United States)

A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

Vranish, John M. (Inventor)

2010-01-01

68

Stem cells for tooth engineering.  

OpenAIRE

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 studie...

Bluteau, G.; H-u, Luder; Bari, C.; Ta, Mitsiadis

2008-01-01

69

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 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

70

From Hopeless to Good Prognosis: Journey of a Failing Tooth  

Science.gov (United States)

Chronic periodontitis, along with associated clinical findings such as pathologic tooth migration, diastema, functional and aesthetic aberrations, poses an immense challenge to a dental professional. These findings convert clinical decision making into a daunting task and adversely affect the prognosis and the treatment plan for the presenting clinical problem. An interdisciplinary approach aimed at restoring functional and aesthetic needs of the affected individual within the limitations of such a compromised clinical scenario may be a viable alternative to any radical treatment causing loss of natural tooth structure such as extraction. This article reports the usefulness of the interdisciplinary route for managing an otherwise hopeless clinical situation of chronic periodontitis complicated with extreme mobility and pathologic tooth migration, which resulted in compromised function and aesthetics.

Gupta, Saurabh; Deshmukh, Jeevanand; Khatri, Richa; Kulkarni, Vinaya Kumar; Karthik, B

2015-01-01

71

Development of transplanted pulp tissue containing epithelial sheath into a tooth-like structure.  

Science.gov (United States)

The aim of these studies was to find out whether intact neonatal pulp tissue containing residual epithelial cells can induce the development of a tooth-like structure in situ. First maxillary neonatal hamster molar pulps containing adhering undifferentiated epithelial cells were transplanted submucosally in the oral cavity of recipient mothers for periods ranging from 2-8 weeks and the tissues were then processed for light microscopy. Developing tooth-like structures containing mineralised tubular dentine, predentine and a vascularised pulp-like chamber lined with functional odontoblast-like cells were observed in the specimens within 2 weeks of transplantation. Enamel and root formation were not observed. These data indicate that neonatal dental pulp tissues containing epithelial cell remnants have the capacity to develop into tooth-like structures and that this could be the explanation for the development of tooth-like structures sometimes observed in infants after extraction of a natal tooth. PMID:10432194

Lyaruu, D M; van Croonenburg, E J; van Duin, M A; Bervoets, T J; Wöltgens, J H; de Blieck-Hogervorst, J M

1999-08-01

72

Parameters of tooth enamel spin model and its application in EPR-dosimetry  

International Nuclear Information System (INIS)

The authors present a model of spin system of tooth enamel EPR spectra which include two types of parametric centres with axial anisotropy. Spectra of 126 samples of tooth enamel with absorbed dose of 4000 mGy of Co-60 gamma-radiation were investigated basing on the parameters of the model with the use of EPR PS-100X radio spectrometer. The suggested model and the results of measurement of the EPR signal noise component with PS-100X radio spectrometer were used to calculate the error of the absorbed doses in tooth enamel with least-aqua res technique. Optimal conditions for investigation of tooth enamel with EPR PS-100X radio spectrometer were determined. Sensitivity of absorbed dose measurement in tooth enamel at the level of 10-15 mGy was evaluated. The error of absorbed dose calculation was shown not to depend considerably on the degree of dentine extraction from the samples

73

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

74

Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel  

International Nuclear Information System (INIS)

This thesis deals with the 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 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 100 mGy ranges can be easily reconstructed in teeth that 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 the mice irradiated with whole body exposures, were reassessed and shown to be correct within the experimental uncertainty. The sensitivity of humental 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 end point as a sensitive accident or emergency tool for our response capabilities

75

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

76

Mesenchymal Stem Cells and Tooth Engineering  

OpenAIRE

Tooth loss compromises human oral health. Although several prosthetic methods, such as artificial denture and dental implants, are clinical therapies to tooth loss problems, they are thought to have safety and usage time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSCs) are multipotent stem cells which can differentiate into a variety ...

Peng, Li; Ye, Ling; Zhou, Xue-dong

2009-01-01

77

Immediate Implant in Management of Anterior Missing Tooth  

OpenAIRE

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 us...

Harinath Reddy S; Raja Babu P; Madhukar N; Nagendrababu K

2010-01-01

78

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

79

An automatic and effective tooth isolation method for dental radiographs  

Science.gov (United States)

Tooth isolation is a very important step for both computer-aided dental diagnosis and automatic dental identification systems, because it will directly affect the accuracy of feature extraction and, thereby, the final results of both types of systems. This paper presents an effective and fully automatic tooth isolation method for dental X-ray images, which contains up-per-lower jaw separation, single tooth isolation, over-segmentation verification, and under-segmentation detection. The upper-lower jaw separation mechanism is based on a gray-scale integral projection to avoid possible information loss and incorporates with the angle adjustment to handle skewed images. In a single tooth isolation, an adaptive windowing scheme for locating gap valleys is proposed to improve the accuracy. In over-segmentation, an isolation-curve verification scheme is proposed to remove excessive curves; and in under-segmentation, a missing-teeth detection scheme is proposed. The experimental results demonstrate that our method achieves the accuracy rates of 95.63% and 98.71% for the upper and lower jaw images, respectively, from the test database of 60 bitewing dental radiographs, and performs better for images with severe teeth occlusion, excessive dental works, and uneven illumination than that of Nomir and Abdel-Mottaleb's method. The method without upper-lower jaw separation step also works well for panoramic and periapical images.

Lin, P.-L.; Huang, P.-W.; Cho, Y. S.; Kuo, C.-H.

2013-03-01

80

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

81

Proteomic Analysis of Human Tooth Pulp: Proteomics of Human Tooth.  

Czech Academy of Sciences Publication Activity Database

Ro?. 40, ?. 12 (2014), s. 1961-1966. ISSN 0099-2399 R&D Projects: GA ?R(CZ) GA13-17224S; GA ?R(CZ) GAP206/12/0453; GA MZd(CZ) NT14324 Institutional support: RVO:67985823 Keywords : dentin * human pulp * tandem mass spectrometry * tooth proteome * 2-dimensional gel electrophoresis Subject RIV: FF - HEENT, Dentistry Impact factor: 2.788, year: 2013

Eckhardt, Adam; Jágr, Michal; Pataridis, Statis; Mikšík, Ivan

2014-01-01

82

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

83

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

84

Tooth fragment reattachment: An esthetic, biological restoration  

Science.gov (United States)

Coronal fractures of the anterior teeth are a common form of dental trauma. If the original tooth fragment is retained following fracture, reattachment of the fractured fragment to the remaining tooth can provide better and long lasting esthetics, improved function, a positive psychological response, and is a faster and less complicated procedure. This paper reports on coronal tooth fracture case that was successfully treated using adhesive reattachment of fractured fragment and post placement.

Choudhary, Ajay; Garg, Rakesh; Bhalla, Anindya; Khatri, Rohit Kumar

2015-01-01

85

Tooth loss in aggressive periodontitis after active periodontal therapy. Patient and tooth related prognostic factors  

OpenAIRE

Abstract Objectives: To assess prognostic factors for tooth loss after active periodontal therapy (APT) in patients with aggressive periodontitis (AgP) on tooth-level. Material and Methods: 84 patients with AgP were re-evaluated after a mean period of 10.5 years of Supportive Periodontal Therapy (SPT). 2154 teeth were entered into the model. The tooth-related factors: baseline bone loss, tooth location and type, furcation involvement (FI), regenerative therapy, and abutment sta...

Ba?umer, Amelie; Pretzl, Bernadette; Cosgarea, Raluca; Kim, Ti-sun; Reitmeir, Peter; Eickholz, Peter; Dannewitz, Bettina

2011-01-01

86

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

87

Tooth use in Aboriginal Australia  

Directory of Open Access Journals (Sweden)

Full Text Available The study of dental casts taken from living people avoids the ethical problems of research into human remains, while providing valuable information about diet and life styles. This article describes a study of tooth wear in dental casts of three different groups of Australian Aborigines. The authors describe their methods of recording and report differential patterns of wear in the different groups. Preliminary interpretation relates the wear patterns both to diet and to the use of teeth as tools in a range of cultural activities, results which are potentially relevant to other groups of hunter-gatherers, past and present.

Anna Clement

2008-09-01

88

Investigation of EPR signals on tooth enamel  

International Nuclear Information System (INIS)

Calcified tissues are involved in continues metabolic process in human organism exchanging a number of chemical elements with environment. The rate of biochemical reactions is tissue dependent and the slowest one at the tooth enamel, the most mineralized tissue of human organism. The long time stability and unique chemical composition make tooth enamel suitable for number of application. The assessment of individual radiation dose by Electron Paramagnetic Resonance (EPR) and evaluations of elemental composition by Instrumentation Neutron Activation Analysis (INAA) are the well known procedures where properties of tooth enamel intensively used. The current work is focused on investigation of EPR signals and determination of chemical composition on several teeth samples having different origin. The EPR spectra and INAA element content of milk tooth, caries tooth, and paradantose tooth have been compared to each other. The results showed that the intensity of EPR signal is much higher for the caries tooth than the for paradantose tooth that is in agreement with depleted Ca content

89

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).

90

EPR-dosimetry with tooth enamel for low doses  

International Nuclear Information System (INIS)

Results are presented for electron paramagnetic resonance (EPR) dosimetry with tooth enamel that focus on the dose region below 100 mGy. Three uncontaminated molars were gamma-irradiated in steps of 10-100 mGy and then in larger steps to 400 mGy. The spectra were evaluated using a deconvolution method including a simulated powder spectrum for extracting the dose related EPR signal of tooth enamel. The dose related signal intensity and the variability between samples were evaluated to investigate the feasibility to reconstruct irradiation doses below 100 mGy. Averaged signal amplitudes as well as the signal amplitudes for single sample were analysed. The performance parameters, critical dose and limit of detection, were calculated and compared with the averaged signal amplitudes of sets of five samples of a pool of mixed tooth samples originating from the same source but irradiated from 100 to 1500 mGy. The values of performance parameters were found to depend on the number and type of samples included in assessment. The evaluated critical dose varied between 131 and 50 mGy for measurements of single sample, and 73 and 33 mGy for average amplitudes of three and five samples, respectively. For exposures below 100 mGy the dose related EPR-signal amplitude was found to correlate with the applied dose only for one of three samples for which the evaluated critical dose was 50 mGy

91

Controlling the Number of Tooth Rows  

Science.gov (United States)

The organization and renewal capacity of teeth vary greatly among vertebrates. Mammals have only one row of teeth that are renewed at most once, whereas many nonmammalian species have multirowed dentitions and show remarkable capacity to replace their teeth throughout life. Although knowledge on the genetic basis of tooth morphogenesis has increased exponentially over the past 20 years, little is known about the molecular mechanisms controlling sequential initiation of multiple tooth rows or restricting tooth development to one row in mammals. Mouse genetics has revealed a pivotal role for the transcription factor Osr2 in this process. Loss of Osr2 caused expansion of the expression domain of Bmp4, a well-known activator of tooth development, leading to the induction of supernumerary teeth in a manner resembling the initiation of a second tooth row in nonmammalian species.

Marja L. Mikkola (University of Helsinki; Institute of Biotechnology REV)

2009-08-25

92

Possibilities of ESR-spectroscopy of the tooth enamel for in vivo determination of the radiation dose  

International Nuclear Information System (INIS)

A review of recent publications on the topic is presented. The characteristics of the tooth as an in vivo dosemeter for the assessment of the individual cumulated dose are analysed. The correlation between the intensity of ESR-signal and the dose as well as the distinguishing of the signal caused by the native crystal structure of the tooth enamel and the one induced during the previous X-ray diagnostic procedures is discussed. The possibilities for in vivo measurement (without preliminary extraction of the tooth) is also reported. 4 figs., 44 refs

93

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)

94

Digital Radiography for Determination of Primary Tooth Length: In Vivo and Ex Vivo Studies  

Science.gov (United States)

Background. Methods for determining the root canal length of the primary tooth should yield accurate and reproducible results. In vitro studies show some limitations, which do not allow their findings to be directly transferred to a clinical situation. Aim. To compare the accuracy of radiographic tooth length obtained from in vivo digital radiograph with that obtained from ex vivo digital radiograph. Method. Direct digital radiographs of 20 upper primary incisors were performed in teeth (2/3 radicular resorption) that were radiographed by an intraoral sensor, according to the long-cone technique. Teeth were extracted, measured, and mounted in a resin block, and then radiographic template was used to standardise the sensor-target distance (30?cm). The apparent tooth length (APTL) was obtained from the computer screen by means of an electronic ruler accompanying the digital radiography software (CDR 2.0), whereas the actual tooth length (ACTL) was obtained by means of a digital calliper following extraction. Data were compared to the ACTL by variance analysis and Pearson's correlation test. Results. The values for APTL obtained from in vivo radiography were slightly underestimated, whereas those values obtained from ex vivo were slightly overestimated. No significance was observed (P ? 0.48) between APTL and ACTL. Conclusion. The length of primary teeth estimated by in vivo and ex vivo comparisons using digital radiography was found to be similar to the actual tooth length. PMID:25802894

Basso, Maria D.; Jeremias, Fabiano; Cordeiro, Rita C. L.; Santos-Pinto, Lourdes

2015-01-01

95

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

96

Assessment of proprioceptive allodynia after tooth-clenching exercises  

DEFF Research Database (Denmark)

To (A) evaluate test-retest reliability of vibrotactile sensitivity in the masseter muscle and (B) test if (1) the vibration threshold is decreased after experimental tooth clenching, (2) intense vibrations exacerbate pain after tooth clenching, (3) pain and fatigue are increased after tooth clenching, and (4) pressure pain thresholds are decreased after tooth clenching.

Dawson, Andreas; List, Thomas

2012-01-01

97

Three Ways To Be a Saber-Toothed Cat  

Science.gov (United States)

Saber-toothed carnivores, until now, have been divided into two groups: scimitar-toothed cats with shorter, coarsely serrated canines coupled with long legs for fast running, and dirk-toothed cats with more elongate, finely serrated canines coupled to short legs built for power rather than speed. In the Pleistocene of North America, as in Europe, the scimitar-cat was Homotherium; the North American dirk-tooth was Smilodon. We now describe a new sabercat from the Early Pleistocene of Florida, combining the scimitar-tooth canine with the short, massive limbs of a dirk-tooth predator. This presents a third way to construct a saber-toothed carnivore.

Martin, L. D.; Babiarz, J. P.; Naples, V. L.; Hearst, J.

98

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

99

Dose estimation by ESR on tooth enamel from two workers exposed to radiation due to the JCO accident  

International Nuclear Information System (INIS)

Electron spin resonance (ESR) dosimetry is useful to estimate the external dose for the general population as well as for occupational workers in a nuclear emergency. Three teeth were extracted from two exposed workers (A and B) related to the JCO criticality accident. Tooth enamel was carefully separated from other tooth parts and subjected to ESR dosimetry. Doses equivalent to the ?-ray dose of 60Co were estimated as follows: for worker A, the buccal and lingual sides of the eighth tooth in the upper right side, 11.8±3.6 and 12.0±3.6 Gy, respectively; for worker B, the buccal and lingual sides of the fourth tooth in the upper right side and the fifth tooth in the upper left side, 11.3±3.4 and 10.8±3.3 Gy, 11.7±3.5 and 11.4±3.4 Gy, respectively. The estimated doses were found to be similar and not dependent on the tooth positions, whether the buccal or lingual sides in each tooth. (author)

100

ATTITUDE AND KNOWLEDGE TOWARDS TOOTH AVULSION AMONG SPORTS TEACHERS  

OpenAIRE

Background: Tooth avulsion is one of the commonest types of physical sport injury. Themanagement of these cases is critical in order to prevent complete loss of tooth and its subsequentconsequences. The prognosis of such avulsed tooth depends on prompt treatment. The emergencymanagement of such avulsed tooth is made by the sports teacher who is present at the sports ground. Thefirst–aid knowledge about tooth avulsion is must for the sports teacher. Aim: The objective of the presentstudy was...

FARHEEN USTAD; MOHD INAYATULLAH KHAN; PRIYAYANKA BHUSHAN; FAREEDI MUKRAM ALI

2013-01-01

101

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Learn more How Do I Care for My Child's Baby Teeth? The History of Dental Advances Are ... What is Dental Amalgam (Silver Filling)? Is My Child at Risk for Early Childhood Tooth Decay? Learn ...

102

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Children's Oral Health Headaches and Jaw Pain? Check Your Posture! Pacifiers ... Effects What is Orofacial Pain? Why is Oral Health Important for Men? What is Baby Bottle Tooth ...

103

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Children's Oral Health How Do I Care for My Child's Baby ... is Baby Bottle Tooth Decay? Why is Oral Health Important for Men? What is Dental Amalgam (Silver ...

104

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Children's Oral Health How Do I Care for My Child's Baby ... for Early Childhood Tooth Decay? Why is Oral Health Important for Men? Learn what those dental words ...

105

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Learn what those dental words mean. The Life of a Tooth games Home | InfoBites | Find a Dentist | ... Privacy Statement | Terms and Conditions © 1996-2015 Academy of General Dentistry. All Rights Reserved.

106

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Children's Oral Health What is Dental Amalgam (Silver Filling)? What is ... is Baby Bottle Tooth Decay? Why is Oral Health Important for Men? What is Orofacial Pain? Learn ...

107

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Children's Oral Health When Should My Child First See a Dentist? ... Start by Visiting the Dentist Why is Oral Health Important for Men? Check Menstrual Calendar for Tooth ...

108

Orthodontic Tooth Movement with Clear Aligners  

OpenAIRE

Clear aligners provide a convenient model to measure orthodontic tooth movement (OTM). We examined the role of in vivo aligner material fatigue and subject-specific factors in tooth movement. Fifteen subjects seeking orthodontic treatment at the University of Florida were enrolled. Results were compared with data previously collected from 37 subjects enrolled in a similar protocol. Subjects were followed prospectively for eight weeks. An upper central incisor was programmed to move 0.5?mm. ...

Drake, Carl T.; Mcgorray, Susan P.; Calogero Dolce; Madhu Nair; Wheeler, Timothy T.

2012-01-01

109

Molecular regulatory mechanism of tooth root development  

OpenAIRE

The root is crucial for the physiological function of the tooth, and a healthy root allows an artificial crown to function as required clinically. Tooth crown development has been studied intensively during the last few decades, but root development remains not well understood. Here we review the root development processes, including cell fate determination, induction of odontoblast and cementoblast differentiation, interaction of root epithelium and mesenchyme, and other molecular mechanisms...

Huang, Xiao-feng; Chai, Yang

2012-01-01

110

Prevalence of tooth transposition in Greek population.  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: To investigate the prevalence of tooth transposition in a sample of Greek dental patients. STUDY DESIGN: Epidemiological study. TIME AND PLACE OF ACTION: Prefecture of Drama, time period 2001-2006. MATERIALS AND METHODS: The first author examined in her private practice 2034 consecutive patients seeking dental treatment. Patients with nationality other than Greek, individuals below 13 years of age with primary or mixed dentitions, patients without panoramic radiographs, patients with syndromes, as well as those who had more than one permanent tooth missing were excluded from the initial sample. In total, 1113 patients were assessed (288 men, 825 women with a mean age of 36.1 years (range: 13.1-73.0 years. MAIN MEASUREMENTS: Tooth transposition was investigated my means of clinical examination through observation and palpation, as well as with radiographic examination using panoramic radiographs. Results were analyzed with descriptive statistics. RESULTS: In total, only one case was found with tooth transposition presenting complete bilateral transposition between canine - lateral incisor in the maxilla. The percentage of patients with tooth transposition in the total dental population examined was 0.09%. The prevalence of this phenomenon in females was 0.12%, whereas in males it was 0%. Men / women ratio was found 0:1. CONCLUSIONS: Tooth transposition in Greek population is rather rare, it is most often encountered in females and concerns mostly maxillary canines and lateral incisors.

Maria Hatzoudi

2006-01-01

111

Wnt5a plays a crucial role in determining tooth size during murine tooth development.  

Science.gov (United States)

We have previously demonstrated that tooth size is determined by dental mesenchymal factors. Exogenous bone morphogenetic protein (BMP)4, Noggin, fibroblast growth factor (FGF)3 and FGF10 have no effect on tooth size, despite the expressions of Bmp2, Bmp4, Fgf3, Fgf10 and Lef1 in the dental mesenchyme. Among the wingless (Wnt) genes that are differentially expressed during tooth development, only Wnt5a is expressed in the dental mesenchyme. The aims of the present study were to clarify the expression pattern of Wnt5a in developing tooth germs and the role of Wnt5a in the regulation of tooth size by treatment with exogenous WNT5A with/without an apoptosis inhibitor on in vitro tooth germs combined with transplantation into kidney capsules. Wnt5a was intensely expressed in both the dental epithelium and mesenchyme during embryonic days 14-17, overlapping partly with the expressions of both Shh and Bmp4. Moreover, WNT5A retarded the development of tooth germs by markedly inducing cell death in the non-dental epithelium and mesenchyme but not widely in the dental region, where the epithelial-mesenchymal gene interactions among Wnt5a, Fgf10, Bmp4 and Shh might partly rescue the cells from death in the WNT5A-treated tooth germ. Together, these results indicate that WNT5A-induced cell death inhibited the overall development of the tooth germ, resulting in smaller teeth with blunter cusps after tooth-germ transplantation. Thus, it is suggested that Wnt5a is involved in regulating cell death in non-dental regions, while in the dental region it acts as a regulator of other genes that rescue tooth germs from cell death. PMID:21879290

Cai, Jinglei; Mutoh, Noriko; Shin, Jeong-Oh; Tani-Ishii, Nobuyuki; Ohshima, Hayato; Cho, Sung-Won; Jung, Han-Sung

2011-09-01

112

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

Energy Technology Data Exchange (ETDEWEB)

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.

Toyoda, Shin E-mail: toyoda@dap.ous.ac.jp; Tanizawa, Honami; Romanyukha, A.A.; Miyazawa, Chuzou; Hoshi, Masaharu; Ueda, Yuji; Nitta, Yumiko

2003-10-01

113

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

114

Ultrasonographic Detection of Tooth Flaws  

Science.gov (United States)

The goal of our work is to adapt pulse-echo ultrasound into a high resolution imaging modality for early detection of oral diseases and for monitoring treatment outcome. In this talk we discuss our preliminary results in the detection of: demineralization of the enamel and dentin, demineralization or caries under and around existing restorations, caries on occlusal and interproximal surfaces, cracks of enamel and dentin, calculus, and periapical lesions. In vitro immersion tank experiments are compared to results from a handpiece which uses a compliant delay line to couple the ultrasound to the tooth surface. Because the waveform echoes are complex, and in order to make clinical interpretation of ultrasonic waveform data in real time, it is necessary to automatically interpret the signals. We apply the dynamic wavelet fingerprint algorithms to identify and delineate echographic features that correspond to the flaws of interest in teeth. The resulting features show a clear distinction between flawed and unflawed waveforms collected with an ultrasonic handpiece on both phantom and human cadaver teeth.

Bertoncini, C. A.; Hinders, M. K.; Ghorayeb, S. R.

2010-02-01

115

An Alternative Efficient Technique For Thin Tooth Sectioning  

Directory of Open Access Journals (Sweden)

Full Text Available Background: The importance of tooth sectioningis realized in disasters such as earthquake, airplanecrash investigation, terror, micro leakage studies, ageestimation etc. The objective of this study was to developa simple method to make thin sections (approximately100 mm from freshly extracted teeth.Methods: One hundred and twenty human premolarsrecently extracted for orthodontic purpose were used forthis study. The teeth were stored in 0.5% chorlaraminefor 2 weeks and were not allowed to dry at any stageof the experiment. The teeth were thoroughly washedin distilled water teeth and then were sectionedbuccolingually from crown to the root portion.Results: A detailed embedding-cutting-mountingprocedure is described. The prepared thin groundsections were then examined under a Polarised lightmicroscope for the enamel and the dentine, as well asthe caries lesions can clearly be distinguished.Conclusion: This is an effective and efficient methodfor preparation of ground sections in which the hardtissue details are preserved.

Muneer Gohar Babar

2011-06-01

116

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 Araújo; Silveira, Ingrid Thays de Melo; Pinto, Magaly Suênya 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

117

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

118

Preimplantation filling of tooth socket with ?-tricalcium phosphate/polylactic-polyglycolic acid (?-TCP/PLGA root analogue: clinical and histological analysis in a patient  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. Bone resorption is a physiological process after tooth extraction. The use of bone substitutes to fill the tooth socket is suggested to prevent bone resorption and establish good bone architecture for implant placement. A pure ß-tricalcium phosphate coated with copolymer (polylactic-polyglycolic acid as a root analogue, is suitable for filling tooth sockets. Case report. We presented a patient successfully treated with root analogue after extraction of the right second lower premolar. Three months later, the patient was planned for the placement of six TE® ITI dental implants into the mandible. During the surgery, the biopsy of bone-like tissue from the previously treated socket was taken. All the implants were immediately loaded due to good primary stability. Histological analysis of the specimen revealed fibrous healing in the area treated with root analogue. Conclusion. The use of ß-tricalcium phosphate coated with copolymers after tooth extraction enables satisfactory bone architecture for consequent implant treatment.

Kokovi? Vladimir

2011-01-01

119

Adhesion of Dental Materials to Tooth Structure  

Science.gov (United States)

The understanding and proper application of the principles of adhesion has brought forth a new paradigm in the realm of esthetic dentistry. Modern restorative tooth procedures can now conserve the remaining tooth-structure and also provide for the strengthening of the tooth. Adhesive restorative techniques call for the application and curing of the dental adhesive at the interface between the tooth tissue and the filling material. Hence the success of the restoration depends largely on the integrity of this interface. The mechanism of adhesion of the bonding materials to the dental hard tissue will be discussed in this paper. There are four main steps that occur during the application of the dental adhesive to the oral hard tissues: 1) The first step is the creation of a microstructure in the tooth enamel or dentin by means of an acidic material. This can be through the application of a separate etchant or can be accomplished in situ by the adhesive/primer. This agent has to be effective in removing or modifying the proteinaceous “smear” layer, which would otherwise act as a weak boundary layer on the surface to be bonded. 2) The primer/adhesive must then be able to wet and penetrate the microstructure created in the tooth. Since the surface energies of etched enamel and that of etched dentin are different finding one material to prime both types of dental tissues can be quite challenging. 3) The ionomer types of materials, particularly those that are carboxylate ion-containing, can chemically bond with the calcium ions of the hydroxyapatite mineral. 4) Polymerization in situ allows for micromechanical interlocking of the adhesive. The importance of having the right mechanical properties of the cured adhesive layer and its role in absorbing and dissipating stresses encountered by a restored tooth will also be discussed.

Mitra, Sumita B.

2000-03-01

120

Hydroxyapatite coating on damaged tooth surfaces by immersion  

International Nuclear Information System (INIS)

Hydroxyapatite (HAp) was coated on scratched areas of a human tooth and HAp disks by the immersion method in a HAp colloidal solution (?20 ?m of average diameter dispersed in DI water). The surface morphologies of the scratched area after immersion for 1-3 months were investigated showing that the damaged surfaces were remarkably recovered. Then, the mechanical property and chemical stability of the HAp coating layers on both specimens were determined via the Vickers hardness test and concentration measurement of extracted Ca2+ ions, respectively, after strong acidic treatment. The cellular behavior of mouse calvaria-derived pre-osteoblastic cells (MC3T3-E1) was also examined on the HAp layers regenerated on micro-scratched HAp disks for the purpose of their potential applications on maxillofacial bone conservation and reconstruction for prosthetic dentistry, and artificial disk preparation of a vertebral column. The notable loss of Ca2+ ions under a highly acidic condition was not observed in the layers coated by HAp adsorption, indicating that the coating surface was well adhered with the original surfaces of the respective specimen. Moreover, the HAp adsorption did not adversely affect the adhesion, growth and proliferation of MC3T3-E1 cells on the coated HAp layers for up to 21 days. These results suggest that the HAp coating on the scratched areas of the tooth would be effectively applicable for the development of long-term prevention of development of long-term prevention of micro-cleavage and tooth health supporters to reduce discoloration and further maxillofacial and orthopedic applications.

121

The evolution of dinosaur tooth enamel microstructure.  

Science.gov (United States)

The evolution of tooth enamel microstructure in both extinct and extant mammalian groups has been extensively documented, but is poorly known in reptiles, including dinosaurs. Previous intensive sampling of dinosaur tooth enamel microstructure revealed that: (1) the three-dimensional arrangement of enamel types and features within a tooth-the schmelzmuster-is most useful in diagnosing dinosaur clades at or around the family level; (2) enamel microstructure complexity is correlated with tooth morphology complexity and not necessarily with phylogenetic position; and (3) there is a large amount of homoplasy within Theropoda but much less within Ornithischia. In this study, the examination of the enamel microstructure of 28 additional dinosaur taxa fills in taxonomic gaps of previous studies and reinforces the aforementioned conclusions. Additionally, these new specimens reveal that within clades such as Sauropodomorpha, Neotheropoda, and Euornithopoda, the more basal taxa have simpler enamel that is a precursor to the more complex enamel of more derived taxa and that schmelzmusters evolve in a stepwise fashion. In the particularly well-sampled clade of Euornithopoda, correlations between the evolution of dental and enamel characters could be drawn. The ancestral schmelzmuster for Genasauria remains ambiguous due to the dearth of basal ornithischian teeth available for study. These new specimens provide new insights into the evolution of tooth enamel microstructure in dinosaurs, emphasizing the importance of thorough sampling within broadly inclusive clades, especially among their more basal members. PMID:20518758

Hwang, Sunny H

2011-02-01

122

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

123

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

124

Interactive tooth partition of dental mesh base on tooth-target harmonic field.  

Science.gov (United States)

The accurate tooth partition of dental mesh is a crucial step in computer-aided orthodontics. However, tooth boundary identification is not a trivial task for tooth partition, since different shapes and their arrangements vary substantially among common clinical cases. Though curvature field is traditionally used for identifying boundaries, it is normally not reliable enough. Other methods may improve the accuracy, but require intensive user interaction. Motivated by state-of-the-art general interactive mesh segmentation methods, this paper proposes a novel tooth-target partition framework that employs harmonic fields to partition teeth accurately and effectively. In addition, a refining strategy is introduced to successfully segment teeth from the complicated dental model with indistinctive tooth boundaries on its lingual side surface, addressing an issue that had not been solved properly before. To utilise high-level information provided by the user, smart and intuitive user interfaces are also proposed with minimum interaction. In fact, most published interactive methods specifically designed for tooth partition are lacking efficient user interfaces. Extensive experiments and quantitative analyses show that our tooth partition method outperforms the state-of-the-art approaches in terms of accuracy, robustness and efficiency. PMID:25464355

Zou, Bei-ji; Liu, Shi-jian; Liao, Sheng-hui; Ding, Xi; Liang, Ye

2015-01-01

125

Clinical, radiological and histological diagnoses of periapical periodontitis spreading to the adjacent tooth: A case of endodontic failure  

Directory of Open Access Journals (Sweden)

Full Text Available Aims: This article describes the apical infection in endodontically treated tooth 4.5 that spread to adjacent tooth 4.4. Case Report: A 52-year-old woman was referred for the presence of radiolucency extending from tooth 4.5 and mental foramen. Spontaneous symptoms were present. Tooth 4.5 showed poor-quality endodontics. The vitality of tooth 4.4 was negative, even though no mechanical trauma had been reported, nor was caries present. Both teeth were sensitive to percussion. Endodontic re-treatment of 4.5 and endodontic treatment of 4.4 were performed in a single visit. A large amount of endodontic sealer squeezed mesially from the root of tooth 4.5, where a partial horizontal root fracture was hypothesized. 6-, 12-, and 18-month radiographic follow-ups, by both periapical and cone-beam computed tomography (CBCT analyses, showed incomplete osseous healing. CBCT excluded root fracture on 4.5. Local symptoms were still present. Clinical and radiological conditions led to extractions, and a cystic lesion was enucleated for histopathologic analyses. Histopathologic diagnosis was a periapical cyst. The supposed partial horizontal root fracture of 4.5 was actually a large lateral canal. Although the root canal treatments followed high standards in terms of quality, a persistent chronic infection developed histologically. The cystic lesion was one consistent reason for the unsuccessful healing of 4.5.

Luigi Cianconi

2013-07-01

126

Preventive orthodontic management of tooth transposition.  

Science.gov (United States)

The contemporary orthodontics should highlight the periodical control of growth and dental development in order to intercept possible disorders in facial growth and tooth eruption. This may allow avoidance or simplification of corrective orthodontic treatment, making it faster and less aggressive. Tooth transposition, a genetically determined eruptive disturbance, presents a relatively low prevalence in the world population and primarily affects maxillary canines and premolars. This paper presents an option for interceptive treatment of bilateral transposition of maxillary canine and premolar diagnosed early in a young individual. Longitudinal follow-up of RME performed in adequate timing to redirect the eruption pathway of permanent maxillary canines is presented. PMID:25745710

Cardoso, Mauricio de Almeida; Guedes, Fabio Pinto; Paranhos, Luiz Renato; Garib, Daniela Gamba; Capelozza Filho, Leopoldino

2014-01-01

127

ESR dosimetry using human tooth enamel  

International Nuclear Information System (INIS)

To estimate the individual cumulative dose of atomic bomb (A-bomb) survivors or radiologic technologists by measuring electron spin resonance (ESR) of teeth, some characteristics of tooth enamel as ESR dosimeter were studied. The ESR signal of CO33- was stable and increased linearly with exposed dose. The response of ESR signal, however, was changed with photon energy. This indicates that the exposed radiation quality must be considered in evaluating the absorbed dose. The merit of this method is that it permits direct estimation of the absorbed dose by measuring the intensity of ESR of tooth taken from exposed persons. (author)

128

A study on ESR dating characteristics of tooth enamel fossils  

International Nuclear Information System (INIS)

The characteristics of ESR signals used in the dating of animal tooth enamel fossils have been investigated. According to the comparison of the results obtained from tooth enamel with those from pure substance and the study by positron annihilation technique, it can be concluded that the paramagnetic centers of tooth enamel is produced by PO43- ion formed F centers

129

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

130

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

131

Recent Approaches in Tooth Engineering Research.  

Czech Academy of Sciences Publication Activity Database

Ro?. 60, Suppl 1 (2014), s. 21-29. ISSN 0015-5500 R&D Projects: GA ?R GAP304/11/1418; GA MZd(CZ) NT11420 Institutional support: RVO:67985904 Keywords : engineering * tooth * stem cells * culture techniques Subject RIV: EA - Cell Biology Impact factor: 0.778, year: 2013

Švandová, Eva; Veselá, Barbora; K?ivánek, J.; Hampl, A.; Matalová, Eva

2014-01-01

132

EPR dosimetry with tooth enamel: A review  

Energy Technology Data Exchange (ETDEWEB)

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.

Fattibene, Paola, E-mail: paola.fattibene@iss.i [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00161 Rome (Italy); Callens, Freddy, E-mail: freddy.callens@ugent.b [Ghent University, Department of Solid State Sciences, Krijgslaan 281-S1, B-9000 Gent (Belgium)

2010-11-15

133

EPR dosimetry with tooth enamel: A review.  

Science.gov (United States)

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. PMID:20599388

Fattibene, Paola; Callens, Freddy

2010-11-01

134

Association of tooth loss with hypertension  

Scientific Electronic Library Online (English)

Full Text Available OBJECTIVE: Hypertension may result from changes in dietary quality and nutrient intake. We therefore sought to determine the epidemiological association between tooth loss and hypertension in South African adults. METHODS: This is a secondary data analysis of a cross-sectional survey of a nationally [...] representative sample of adults aged 25 - 70 years who participated in the South African Demographic and Health Survey during 1998 (N=9 098). The primary data were collected using a validated questionnaire, which included information on past experience of tooth loss (partial or complete), use of dental services, tobacco use and other known risk factors for hypertension. Hypertension was defined as having a measured average blood pressure (BP) >160/95 mmHg and/or taking antihypertensive medication. RESULTS: The prevalences of hypertension, any tooth loss and complete edentulousness were 18.1%, 72.2% and 9.4% respectively. Tooth loss was more common among overweight/obese respondents than among those with a normal body mass index (76.7% v. 66.7%; p

Olalekan A, Ayo-Yusuf; Imade J, Ayo-Yusuf.

2008-05-01

135

Life of a Tooth: A Visual Timeline  

Medline Plus

Full Text Available ... Contact InfoBites Quick Reference Learn more Children's Oral Health What is Baby Bottle Tooth Decay? Headaches and ... Home | InfoBites | Find a Dentist | Your Family's Oral Health | Newsroom | RSS About AGD | Contact AGD | Site Map | ...

136

Caspase-7 in molar tooth development.  

Czech Academy of Sciences Publication Activity Database

Ro?. 57, ?. 11 (2012), s. 1474-1481. ISSN 0003-9969 R&D Projects: GA AV ?R IAA600450904 Grant ostatní: GA ?R(CZ) GAP502/12/1285 Institutional research plan: CEZ:AV0Z50450515 Keywords : tooth * apoptosis * mineralisation Subject RIV: FF - HEENT, Dentistry Impact factor: 1.549, year: 2012

Matalová, Eva; Vanden Berghe, T.; Švandová, Eva; Vandenabeele, P.; Healy, C.; Sharpe, P. T.; Tucker, A. S.

2012-01-01

137

Tooth’s Tensions Analysis of Face Worm Gears with Cylindrical Pinion Development of FEA  

Directory of Open Access Journals (Sweden)

Full Text Available Tooth’s tension in lapping process for worm face gear is proposed. The stress analysis of the gear drive is performed using a three-dimensional finite element analysis. The developed simulation is illustrated with numerical examples. This complex and intuitive simulation was created with CAD-CAM, MATH-CAD and FEM support. This simulation contain data collected from EU standards

Gavrila Ion

2009-12-01

138

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

139

Displaced lower third molar tooth into the submandibular space: Two case reports  

OpenAIRE

The aim of this article is to emphasize that the accidental displacement of a lower third molar during extraction is a rare, but potentially serious complication. We present two case reports on a lower third molar tooth dislodged into the submandibular space following its removal from the sockets and the subsequent management of this rare complication. Differences in the direction of displacement, the size of fragment, delay in retrieval, and tissue reactions can all influence this potential ...

Kose, Ibrahim; Koparal, Mahmut; Gu?nes?, Nedim; Atalay, Yusuf; Yaman, Ferhan; Atilgan, Serhat; Kaya, Gurkan

2014-01-01

140

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

OpenAIRE

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. De...

Beheshteh Malekafzali Malekafzali; Amir Ghasemi; Hassan Torabzadeh; Reza Hamedani; Nekoo Tadayon

2013-01-01

141

Computer aided design and analysis of gear tooth geometry  

Science.gov (United States)

A simulation method for gear hobbing and shaping of straight and spiral bevel gears is presented. The method is based upon an enveloping theory for gear tooth profile generation. The procedure is applicable in the computer aided design of standard and nonstandard tooth forms. An inverse procedure for finding a conjugate gear tooth profile is presented for arbitrary cutter geometry. The kinematic relations for the tooth surfaces of straight and spiral bevel gears are proposed. The tooth surface equations for these gears are formulated in a manner suitable for their automated numerical development and solution.

Chang, S. H.; Huston, R. L.

1987-01-01

142

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)

143

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.

144

Effective property of tooth enamel: monoclinic behavior.  

Science.gov (United States)

Human tooth enamel possesses a unique morphology characterized by a repeated cell arrangement, which is composed of varying orientations of hydroxyapatite crystals. In the past, various investigators have reported diverse mechanical properties based on isotropic or orthotropic mechanical models in their experimental and numerical studies. However, these models are insufficient to capture the accurate microstructural effects on the enamel mechanical response. In this paper, a monoclinic anisotropic model, which offers correct descriptions of enamel deformation behaviors, is introduced. The model takes into account the 3D orientation changes of the hydroxyapatite crystals and their spatial elastic property variations. The proposed approach is based on a unit-cell and periodic boundary conditions, and it utilizes the collective deformation characteristics of many rods to determine 13 independent material constants required for the monoclinic model. These constants are necessary to utilize the effective property model to study various mechanical conditions such as abrasion, erosion, wear and fracture of whole tooth enamel. PMID:22405497

Lu, Cunyou; Nakamura, Toshio; Korach, Chad S

2012-05-11

145

Large scale study of tooth enamel  

International Nuclear Information System (INIS)

Human tooth enamel contains traces of foreign elements. The presence of these elements is related to the history and the environment of the human body and can be considered as the signature of perturbations which occur during the growth of a tooth. A map of the distribution of these traces on a large scale sample of the population will constitute a reference for further investigations of environmental effects. One hundred eighty samples of teeth were first analysed using PIXE, backscattering and nuclear reaction techniques. The results were analysed using statistical methods. Correlations between O, F, Na, P, Ca, Mn, Fe, Cu, Zn, Pb and Sr were observed and cluster analysis was in progress. The techniques described in the present work have been developed in order to establish a method for the exploration of very large samples of the Belgian population

146

Update on Charcot-Marie-Tooth Disease  

OpenAIRE

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 p...

Patzko?, A?gnes; Shy, Michael E.

2011-01-01

147

On tribological design in gear tooth contacts  

OpenAIRE

The correct tribological design will have a considerable effect on a gear’s service life and efficiency. The purpose of this thesis is to clarify the impact of variation in the gear tooth flank tribological system on the gear contact load capacity – to increase the understanding of how surface topography and lubricant interact. In this thesis the variation in surface topography inherent in the manufacturing method has been shown, by experimental work and computer simulations, to be an imp...

Bergseth, Ellen

2012-01-01

148

Diagnosis of Charcot-Marie-Tooth Disease  

OpenAIRE

Charcot-Marie-Tooth (CMT) disease or hereditary motor and sensory neuropathy (HMSN) is a genetically heterogeneous group of conditions that affect the peripheral nervous system. The disease is characterized by degeneration or abnormal development of peripheral nerves and exhibits a range of patterns of genetic transmission. In the majority of cases, CMT first appears in infancy, and its manifestations include clumsiness of gait, predominantly distal muscular atrophy of the limbs, and deformit...

Banchs, Isabel; Casasnovas, Carlos; Alberti?, Antonia; Jorge, Laura; Povedano, Mo?nica; Montero, Jordi; Marti?nez-matos, Juan Antonio; Volpini, Victor

2009-01-01

149

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

150

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

151

In vitro differentiation and attachment of human embryonic stem cells on periodontal tooth root surfaces.  

Science.gov (United States)

Periodontal tissue engineering based on cell replacement therapies is a promising field for improved regeneration of tooth supporting structures lost as a result of destructive periodontal diseases. Human embryonic stem cells (hESCs) could become adequate cell source for tissue engineering because of their unlimited proliferative potential and ability to differentiate to all somatic cell types. The aim of this study was to analyze the differentiation capacity of hESCs toward periodontal compartment cells and their relationship with tooth root surfaces in vitro. Periodontal ligament fibroblastic cell (PDLF) cultures were established and characterized; hESCs (HUES-9 line) were expanded in undifferentiated state and characterized for pluripotency morphologically and immunohistochemically. Extracted tooth root slices (RS) of 300 microm thickness, prepared with both periodontal and endodontic instrumentation, were used. Three different experimental groups were established: (i) undifferentiated hESC colonies cultured on and around the RS; (ii) undifferentiated hESC colonies cultured on and around RS with PDLF coculture, and (iii) undifferentiated hESC colonies cultured on and around RS with PDLF coculture in osteoinductive medium for 3 weeks. The fibrogenic and osteogenic marker expression was assessed with immunohistochemistry; histological staining and scanning electron microscopy were utilized to determine the relationship between differentiating hESCs and mineralized tooth root structures. Results demonstrate that hESC differentiation is influenced by tooth structures, PDLFs, and osteogenic medium, resulting with increased propensity toward mesenchymal lineage commitment, and formation of soft-hard tissue relationship in close contact areas. The proposed experimental system may facilitate further understanding in development of periodontal structures and contribute to realization of hESCs as a cell source in periodontal tissue engineering applications. PMID:19405785

Inanç, Bülend; Elçin, A Eser; Elçin, Y Murat

2009-11-01

152

Tooth movement alterations by different low level laser protocols: a literature review.  

Science.gov (United States)

Low-Level Laser Therapy (LLLT) provides several benefits for patients receiving orthodontic treatment. According to some literatures, Orthodontic Tooth Movement (OTM) can be enhanced but some investigators have reported contradictory results. This article reviews the literature regarding the different aspects of the use of LLLT on OTM and its alterations. The general data regarding the study design, sample size, wavelength (nm), power (mW), and duration were extracted and recorded independently. Electronic databases of PubMed and ScienceDirect from January 2009 to August 2014 were searched. Also Google Scholar and grey literature was searched for relevant references. Some investigators found that the amount of tooth movement in the Low-Energy Laser Irradiation (LELI) group was significantly greater than in the nonirradiation group by the end of the experimental period. Low-level laser irradiation accelerates the bone remodeling process by stimulating osteoblastic and osteoclastic cell proliferation and function during orthodontic tooth movement. But some researchers have reported that no statistical differences in the mean rate of tooth movement were noted between low energy and high energy experimental sides and their controls. Some evidence shows that low-level laser irradiation accelerates the bone remodeling process and some evidence shows that LLLT has not effect on OTM. In some investigations no statistical differences in the mean rate of tooth movement can be seen between low energy and high energy experimental sides and their controls. It has been shown by authors that laser irradiation can reduce the amount of OTM and a clinical usage for the inhibitory role of low level laser irradiation is enforcing the anchorage unit. PMID:25699160

Seifi, Massoud; Vahid-Dastjerdi, Elahe

2015-01-01

153

ISS protocol for EPR tooth dosimetry  

Energy Technology Data Exchange (ETDEWEB)

The accuracy in Electron Paramagnetic Resonance (EPR) dose reconstruction with tooth enamel is affected by sample preparation, dosimetric signal amplitude evaluation and unknown dose estimate. Worldwide efforts in the field of EPR dose reconstruction with tooth enamel are focused on the optimization of the three mentioned steps in dose assessment. In the present work, the protocol implemented at ISS in the framework of the European Community Nuclear Fission Safety project 'Dose Reconstruction' is presented. A combined mechanical-chemical procedure for ground enamel sample preparation is used. The signal intensity evaluation is carried out with powder spectra simulation program. Finally, the unknown dose is evaluated individually for each sample with the additive dose method. The unknown dose is obtained by subtracting a mean native dose from the back-extrapolated dose. As an example of the capability of the ISS protocol in unknown dose evaluation, the results obtained in the framework of the 2nd International Intercomparison on EPR tooth enamel dosimetry are reported.

Onori, S.; Aragno, D.; Fattibene, P.; Petetti, E.; Pressello, M.C

2000-12-15

154

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

155

Orthodontic tooth movement with clear aligners.  

Science.gov (United States)

Clear aligners provide a convenient model to measure orthodontic tooth movement (OTM). We examined the role of in vivo aligner material fatigue and subject-specific factors in tooth movement. Fifteen subjects seeking orthodontic treatment at the University of Florida were enrolled. Results were compared with data previously collected from 37 subjects enrolled in a similar protocol. Subjects were followed prospectively for eight weeks. An upper central incisor was programmed to move 0.5?mm. every two weeks using clear aligners. A duplicate aligner was provided for the second week of each cycle. Weekly polyvinyl siloxane (PVS) impressions were taken, and digital models were fabricated to measure OTM. Initial and final cone beam computed tomography (CBCT) images were obtained to characterize OTM. Results were compared to data from a similar protocol, where subjects received a new aligner biweekly. No significant difference was found in the amount of OTM between the two groups, with mean total OTM of 1.11?mm. (standard deviation (SD) 0.30) and 1.07?mm. (SD 0.33) for the weekly aligner and biweekly control groups, respectively (P = 0.72). Over eight weeks, in two-week intervals, material fatigue does not play a significant role in the rate or amount of tooth movement. PMID:22928114

Drake, Carl T; McGorray, Susan P; Dolce, Calogero; Nair, Madhu; Wheeler, Timothy T

2012-01-01

156

ISS protocol for EPR tooth dosimetry  

International Nuclear Information System (INIS)

The accuracy in Electron Paramagnetic Resonance (EPR) dose reconstruction with tooth enamel is affected by sample preparation, dosimetric signal amplitude evaluation and unknown dose estimate. Worldwide efforts in the field of EPR dose reconstruction with tooth enamel are focused on the optimization of the three mentioned steps in dose assessment. In the present work, the protocol implemented at ISS in the framework of the European Community Nuclear Fission Safety project 'Dose Reconstruction' is presented. A combined mechanical-chemical procedure for ground enamel sample preparation is used. The signal intensity evaluation is carried out with powder spectra simulation program. Finally, the unknown dose is evaluated individually for each sample with the additive dose method. The unknown dose is obtained by subtracting a mean native dose from the back-extrapolated dose. As an example of the capability of the ISS protocol in unknown dose evaluation, the results obtained in the framework of the 2nd International Intercomparison on EPR tooth enamel dosimetry are reported

157

Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods  

International Nuclear Information System (INIS)

To measure the tooth whitening and the surface and Intrapulpal temperature increase in vitro on freshly extracted upper human central incisors after chemical, Zoom AP light and diode laser activated bleaching. Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n = 10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel, for three applications of 15 min each. Group II was bleached with high intensity advanced power Zoom activation light (Zoom AP), for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 Watt diode laser for three applications of 30 sec each. The whitening degree was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and Intrapulpal. The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Chemical bleaching produces the same whitening effect as Zoom AP light and laser, with no surface or pulpal temperature rise. Laser applicationpulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than Zoom AP light. Diode laser used to activate bleaching gels is not considered dangerous to the vitality of dental pulp using power settings of 2 W.

158

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

International Nuclear Information System (INIS)

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

159

IBA analysis of a possible therapeutic ancient tooth inlay  

Science.gov (United States)

Five pre-Columbian human teeth from the same skeleton found during excavation in an ancient ceremonial center in Mexico, have been analyzed by two conventional Ion Beam Analysis (IBA) techniques: PIXE and 4He RBS. The anthropologists have estimated that the skeleton is about 2000 years old. X-ray radiography studies of one of these teeth have revealed that they contain an inlay in the tooth crown. The IBA methods have been used to study the inlay materials and also the tooth enamel. The IBA studies show that the tooth inlay materials have almost the same atomic composition as the tooth enamel. These results suggest that the tooth inlay were made for therapeutic purposes, using healthy tooth grains as inlay materials which were glued into the prepared teeth to fill it up.

Andrade, E.; Pineda, J. C.; Zavala, E. P.; Murillo, G.; Chavez, R.; Lazcurain, R.; Espinosa, Ma. L.; Villanueva, O.

1998-03-01

160

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)

161

Protection and Reinforcement of Tooth Structures by Dental Coating Materials  

OpenAIRE

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 toot...

Toru Nikaido; Rena Takahashi; Meu Ariyoshi; Junji Tagami; Alireza Sadr

2012-01-01

162

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

163

Fate of HERS during Tooth Root Development  

OpenAIRE

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 c...

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

2009-01-01

164

Thermal induced EPR signals in tooth enamel  

International Nuclear Information System (INIS)

Electron paramagnetic resonance (EPR) spectroscopy was used to detect the effects of temperature on powdered human tooth enamel, not irradiated in the laboratory. Samples were heated at temperature between 350 and 450, at 600 and at 1000 deg. C, for different heating times, between 6 min and 39 h. Changes in the EPR spectra were detected, with the formation of new signals. Possible correlation between the changes in EPR spectra and modifications in the enamel and in the mineral phase of bone detected with other techniques is discussed. The implications for dosimetric applications of signals induced by overheating due to mechanical friction during sample preparation are underlined

165

Mechanically induced EPR signals in tooth enamel  

Energy Technology Data Exchange (ETDEWEB)

Sample preparation of tooth enamel for electron paramagnetic resonance (EPR) dosimetry usually involves mechanical operations. The present study shows that mechanical operations performed without water cooling generate a paramagnetic center inducing a stable isotropic EPR signal with g-value of 2.00320 and linewidth of about 0.1 mT. Using EPR spectrum simulation, the similarity between the mechanically induced signal and the signal generated when the enamel is heated in air at a temperature above 600 deg. C was investigated. Results indicate that the mechanically induced signal is related to sample temperature increase during mechanical friction.

Aragno, D.; Fattibene, P. E-mail: paola.fattibene@iss.it; Onori, S

2001-09-01

166

Mechanically induced EPR signals in tooth enamel  

International Nuclear Information System (INIS)

Sample preparation of tooth enamel for electron paramagnetic resonance (EPR) dosimetry usually involves mechanical operations. The present study shows that mechanical operations performed without water cooling generate a paramagnetic center inducing a stable isotropic EPR signal with g-value of 2.00320 and linewidth of about 0.1 mT. Using EPR spectrum simulation, the similarity between the mechanically induced signal and the signal generated when the enamel is heated in air at a temperature above 600 deg. C was investigated. Results indicate that the mechanically induced signal is related to sample temperature increase during mechanical friction

167

Thermal induced EPR signals in tooth enamel  

Energy Technology Data Exchange (ETDEWEB)

Electron paramagnetic resonance (EPR) spectroscopy was used to detect the effects of temperature on powdered human tooth enamel, not irradiated in the laboratory. Samples were heated at temperature between 350 and 450, at 600 and at 1000 deg. C, for different heating times, between 6 min and 39 h. Changes in the EPR spectra were detected, with the formation of new signals. Possible correlation between the changes in EPR spectra and modifications in the enamel and in the mineral phase of bone detected with other techniques is discussed. The implications for dosimetric applications of signals induced by overheating due to mechanical friction during sample preparation are underlined.

Fattibene, P. E-mail: paola.fattibene@iss.it; Aragno, D.; Onori, S.; Pressello, M.C

2000-12-15

168

Mechanically induced EPR signals in tooth enamel.  

Science.gov (United States)

Sample preparation of tooth enamel for electron paramagnetic resonance (EPR) dosimetry usually involves mechanical operations. The present study shows that mechanical operations performed without water cooling generate a paramagnetic center inducing a stable isotropic EPR signal with g-value of 2.00320 and linewidth of about 0.1 mT. Using EPR spectrum simulation, the similarity between the mechanically induced signal and the signal generated when the enamel is heated in air at a temperature above 600 degrees C was investigated. Results indicate that the mechanically induced signal is related to sample temperature increase during mechanical friction. PMID:11515662

Aragno, D; Fattibene, P; Onori, S

2001-09-01

169

Filling of extraction sockets with autogenous bone in cats Preenchimento de alvéolos dentais de gatos com osso autógeno  

OpenAIRE

PURPOSE: To evaluate bone healing in the extraction socket of the feline mandibular canine tooth after grafting. METHODS: Eighteen adult cats were submitted to unilateral extraction of mandibular canine tooth and divided into three groups. In group 1 (n=6), control, the extraction socket was left empty. In group 2 (n=6), the extraction socket was filled with autogenous cancelous bone from the iliac crest and in group 3 (n=6), with cortical bone chips from the iliac crest. Cats were euthanized...

Adelina Maria da Silva; Wilson Machado Souza; Nair Trevizan Machado de Souza; Marion Burkhardt Koivisto; Patrícia de Athayde Barnabé; Tatiane da Silva Poló

2012-01-01

170

Restoring Esthetics in Traumatic Tooth Fractures with all Ceramic Restorations  

OpenAIRE

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

171

In vitro investigation of heat transfer in human tooth  

Science.gov (United States)

The understanding of heat transfer in human teeth is important for optimizing clinical practice protocols and daily intake instructions. However, it is technically challenging to study the in vitro thermal behavior of human tooth due to its small size and complex biological/geometrical structure. The currently widely used method is based on thermocouples, which has several limitations such as low spatial resolution, contact measurement and, in particular, lack of whole-field information. To address these challenges, an experimental system was developed to measure the whole-field temperature distribution in human tooth in vitro. The human tooth sample was heated at the tooth crown with flowing hot water (60 °C) for 10 s and then cooled down by natural convection of air. The temperature of the whole sectioned sample surface was recorded using an infrared camera. The results demonstrate that the developed system is capable of measuring temperature evolution in small human tooth samples. The biological junction of tooth (e.g., dental-enamel junction) is shown to have great influence on its heat transfer behavior. The present study could open the door for several future applications, e.g., systemic investigation of heat transfer in intact/restored tooth heated with clinical methods for treatment optimization, and measurement of thermal properties for different tooth layers.

Lin, Min; Liu, Q. Da; Xu, Feng; Bai, B. Feng; Lu, T. Jian

2010-03-01

172

Are You Feeding Your Kids Tooth-Friendly Foods?  

Science.gov (United States)

... to dissolve tooth enamel and cause decay. To help children make sensible food choices, here's what parents can do: Recognize foods that are "high risk" for tooth decay. Most people know that sweets such as cookies, candy and cake are poor snack choices for healthy teeth. However, some foods ...

173

Spatial and temporal events in tooth development of Astyanax mexicanus.  

Science.gov (United States)

The Mexican tetra (Astyanax mexicanus), a freshwater teleost fish, is an excellent vertebrate model organism to study tooth development, specifically the spatiotemporal events related to the development of the oral and pharyngeal dentitions. In contrast to the coordinated early tooth development in the premaxilla and mandible, the maxillary teeth develop much later in life at 60?dpf. By analysing a growth series of bone and cartilage stained tetra and histological sectioning of the tooth bearing bones, we track the developmental events of tooth development over ontogeny of this animal. Whole mount in situ hybridisation with bone morphogenetic proteins and their inhibitor Noggin was conducted to track the late tooth development events. Our data show that the first generation teeth are small and unicuspid irrespective of their location. Oral jaw teeth become multicuspid and large over ontogeny while the pharyngeal dentition remains unicuspid and disorganised. Tooth eruption occurs late in the maxillary bone. The distinct expression pattern of the BMP antagonist, Noggin, suggests that Noggin plays an inhibitory role by preventing early tooth development in the maxillary bone. These data further support and highlight the use of the Mexican tetra in understanding the spatio-temporal differences in tooth development in vertebrate jaws. PMID:25290235

Atukorala, Atukorallaya Devi Sewvandini; Franz-Odendaal, Tamara Anne

2014-11-01

174

Patients' self-perceived impacts and prosthodontic needs at the time and after tooth loss  

Scientific Electronic Library Online (English)

Full Text Available Estudos de autopercepção têm demonstrado que a ausência de dentes pode resultar em impactos estéticos, funcionais, psicológicos e sociais, embora nem todos os indivíduos demandam por tratamento protético imediato após a perda dentária. O objetivo do estudo foi avaliar a percepção de pacientes submet [...] idos a exodontia em relação a fatores associados à perda e ao tratamento protético, no momento e após a perda dos dentes. Uma amostra de conveniência de 211 pacientes consecutivos foi avaliada quanto à condição clínica, autopercepção dos impactos orais e necessidade de tratamento, por meio de exame clínico e questionário, no momento e após 3 meses da exodontia. A percepção de impactos da perda dentária foi alta (21-76% no momento e 35-87% após a exodontia). Dos 72,5% pacientes que relataram pretender a reposição protética imediata apenas 8,1% realizaram o tratamento. A motivação financeira foi relatada como o maior impedimento para o tratamento. A análise univariada mostrou associação entre reposição imediata e localização anterior da perda (p=0,00) e extensão do espaço desdentado (p=0,01), entre localização da perda e limitação funcional percebida (p=0,03). O incômodo com a aparência foi relacionado à localização da perda no arco superior (p=0,02), o desejo por tratamento protético foi relacionado à extensão do espaço desdentado (p=0,05). Na maioria dos aspectos avaliados a percepção de problemas associados à perda foi maior no sexo feminino. Conclui-se que, embora a necessidade percebida de tratamento protético seja alta, fatores clínicos e sócio-econômicos são determinantes para a realização do tratamento. Abstract in english Studies on self-perception have demonstrated that tooth loss is associated with esthetic, functional, psychological and social impacts for individuals. However, not all subjects seek treatment immediately after tooth loss, even when desire for replacement is strongly expressed. The aim of this study [...] was to evaluate the perception of patients submitted to tooth extraction about factors associated with tooth loss and prosthodontic treatment, at the time and after extraction. A convenience sample of 211 consecutive patients were clinically evaluated and answered to a questionnaire about perceived impacts and prosthodontic treatment needs. Data were collected at the time of extraction and after a 3-month time interval. Perceived impacts were high (21 to 76% at the time and 35 to 87% after extraction). From 72.5% patients who expressed intention of immediate replacement of edentulous spaces, only 8.1% had actually been treated. Financial limitation was considered the most important factor that restricted access to treatment. Bivariate statistical analysis showed association between immediate dental replacement and anterior tooth loss (p=0.00) and extension of edentulous space (p=0.01). Position of lost teeth was associated to perceived functional limitation (p=0.03). Worsened appearance was associated to tooth loss in the maxillary arch (p=0.02), and desire of prosthodontic treatment was associated to the extension of edentulous space (p=0.05). Perceived impacts were more frequent in women than men. It was concluded that although patients usually expressed prosthodontic treatment needs, clinical and financial issues are determinant factors for tooth replacement.

Linéia Tavares, Teófilo; Cláudio Rodrigues, Leles.

175

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

176

Clinical and esthetic outcomes of single-tooth implants in the anterior maxilla.  

Science.gov (United States)

The aim of this study was to evaluate the clinical and esthetic outcomes of 10 consecutive single-tooth implant restorations in the anterior maxilla. A specific treatment protocol consisting of (1) atraumatic extraction of the failing tooth, (2) placement of an SLActive bone-level implant with simultaneous guided bone regeneration at 6 to 8 weeks postextraction, (3) loading of a provisional restoration at 2 to 3 months following implant placement, (4) production of a customized impression coping, and (5) loading of the definitive all-ceramic abutment and crown 6 months after delivery of the provisional restoration was utilized in all cases. The outcomes were assessed 1 year after loading of the definitive restoration using standard clinical parameters: pink (PES) and white esthetic scores (WES). All implants were successfully integrated, accounting for a 100% survival and success rate. Besides clinical success, the application of the specific treatment protocol may be able to provide esthetically pleasing single-tooth implant restorations in the anterior maxilla, as was demonstrated by the results for PES (7.9 ± 1.7) and WES (7.0 ± 1.5). PMID:22257874

Furze, David; Byrne, Ashley; Donos, Nikolaos; Mardas, Nikos

2012-02-01

177

Fracture in teeth: a diagnostic for inferring bite force and tooth function.  

Science.gov (United States)

Teeth are brittle and highly susceptible to cracking. We propose that observations of such cracking can be used as a diagnostic tool for predicting bite force and inferring tooth function in living and fossil mammals. Laboratory tests on model tooth structures and extracted human teeth in simulated biting identify the principal fracture modes in enamel. Examination of museum specimens reveals the presence of similar fractures in a wide range of vertebrates, suggesting that cracks extended during ingestion or mastication. The use of 'fracture mechanics' from materials engineering provides elegant relations for quantifying critical bite forces in terms of characteristic tooth size and enamel thickness. The role of enamel microstructure in determining how cracks initiate and propagate within the enamel (and beyond) is discussed. The picture emerges of teeth as damage-tolerant structures, full of internal weaknesses and defects and yet able to contain the expansion of seemingly precarious cracks and fissures within the enamel shell. How the findings impact on dietary pressures forms an undercurrent of the study. PMID:21507194

Lee, James J-W; Constantino, Paul J; Lucas, Peter W; Lawn, Brian R

2011-11-01

178

The 4th international comparison on EPR dosimetry with tooth enamel  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Muenchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit of which were also calculated by the organizers.

Fattibene, P., E-mail: paola.fattibene@iss.it [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00162 Rome (Italy); Wieser, A. [Helmholtz Zentrum Muenchen, Neuherberg D-85764 (Germany); Adolfsson, E. [Linkoeping University, SE-58185 Linkoeping (Sweden); Benevides, L.A. [Naval Dosimetry Center, Bethesda MD 20889-5600 (United States); Brai, M. [University of Palermo, I-90128 Palermo (Italy); Callens, F. [Ghent University, B-9000 Gent (Belgium); Chumak, V. [Research Center for Radiation Medicine AMS, 04050 Kiev (Ukraine); Ciesielski, B. [Medical University of Gdansk, 80-211 Gdansk (Poland); Della Monaca, S. [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00162 Rome (Italy); Regina Elena Institute, I-00144 Rome (Italy); Emerich, K. [Medical University of Gdansk, 80-211 Gdansk (Poland); Department of Paediatric Dentistry, 80-208 Gdansk (Poland); Gustafsson, H. [Linkoeping University, SE-58185 Linkoeping (Sweden); Hirai, Y. [Radiation Effects Research Foundation, Minami-ku, Hiroshima 732-0815 (Japan); Hoshi, M. [Hiroshima University, Minami-ku, Hiroshima 734-8553 (Japan); Israelsson, A. [Linkoeping University, SE-58185 Linkoeping (Sweden); Ivannikov, A. [Medical Radiological Research Center, Obninsk, Kaluga region (Russian Federation); Ivanov, D. [Institute of Metal Physics, Yekaterinburg 620041 (Russian Federation); Kaminska, J. [Medical University of Gdansk, 80-211 Gdansk (Poland); Ke, Wu [Beijing Institute of Radiation Medicine, Beijing 100850 (China); Lund, E. [Linkoeping University, SE-58185 Linkoeping (Sweden); Marrale, M. [University of Palermo, I-90128 Palermo (Italy)

2011-09-15

179

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

180

Fast image processing on chain board of inverted tooth chain  

Science.gov (United States)

Discussed ordinary image processing technology of inverted tooth chain board, including noise reduction, image segmentation, edge detection and contour extraction etc.. Put forward a new kind of sub-pixel arithmetic for edge orientation of circle. The arithmetic first did edge detection to image by Canny arithmetic, so as to enhance primary orientation precision of edge, then calculated gradient direction, and then interpolated gradient image (image that was detected by Sobel arithmetic) along gradient direction, last obtained sub-pixel orientation of edge. Performed two kinds of least-square fitting methods for line edge to getting its sub-pixel orientation, from analysis and experiments, the orientation error of improved least-square linear fitting method was one quarter of ordinary least-square linear fitting error under small difference of orientation time. The sub-pixel orientation of circle made resolution of CCD increase 42 tines, which enhanced greatly orientation precision of image edge. For the need of quick on-line inspection next step, integrated the whole environment containing image preprocess, Hough conversion of line, setting orientation & direction of image, sub-pixel orientation of line and circle, output of calculation result. The whole quick processing course performed without operator, processing tine of single part is less than 0.3 second. The sub-pixel orientation method this paper posed fits precision orientation of image, and integration calculation method ensure requirement of quick inspection, and lays the foundations for on-line precision visual measurement of image.

Liu, Qing-min; Li, Guo-fa

2007-12-01

181

Delayed tooth replantation: MTA as root canal filling  

Scientific Electronic Library Online (English)

Full Text Available MTA has been investigated as a root-end filling material. Its mechanism of action has some similarities to that of Ca(OH)2. The purpose of this study was to evaluate the repair process taking place in the delayed replantation of monkey teeth using calcium hydroxide and MTA as root canal filling mate [...] rials. Five monkeys had their lateral incisors extracted and bench-dried for 60 minutes. After root canal preparation, the teeth were assigned to two groups according to root canal filling material: I, calcium hydroxide; and II, MTA. The same treatment sequence was followed for both groups: coronal seal, periodontal ligament removal, immersion of the tooth in 2% acidulated-phosphate sodium fluoride, irrigation of the socket with saline and replantation. Both groups exhibited replacement resorption, areas of ankylosis and absence of inflammatory root resorption. Statistically similar results (p > 0.05) were observed for both groups regarding replacement root resorption, but the groups differed significantly (p

Sônia Regina, PANZARINI; Celso Koogi, SONODA; Célia Tomiko Matida Hamata, SAITO; Elizane Ferreira, HAMANAKA; Wilson Roberto, POI.

182

Collagen analysis in human tooth germ papillae  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A matriz extracelular (MEC) tem um papel importante na regulação do crescimento e na diferenciação e organização dos tecidos. Com base nestes aspectos o objetivo do deste estudo foi analisar o colágeno, maior componente orgânico da MEC da polpa dentária, na papila de germes dentários humanos, em dif [...] erentes fases do desenvolvimento. Foram obtidos fragmentos de maxilas e mandíbulas de 9 fetos humanos com 10 a 22 semanas de vida intra-uterina, dos quais foram analisados 16 germes dentários (1 em estágio de capuz, 8 em estágio de campânula precoce e 7 em estágio de campânula tardia). Secções histológicas seriadas foram coradas com hematoxilina e eosina, tricrômico de Masson e técnica de coloração do picrosirius. Ambos os tipos de colágeno na papila dentária foram somente detectados pela técnica de coloração do picrosirius usando microscopia de luz polarizada. Colágeno tipo III foi detectado em todas as amostras. Colágeno tipo I estava presente em áreas focais da papila dental em algumas amostras. Concluiu-se que o colágeno tipo III mostrou-se um componente regular da papila de germes dentários humanos, enquanto o colágeno tipo I esteve presente em quantidade significativamente menor. Abstract in english The extracellular matrix (ECM) performs a very important role in growth regulation and tissue differentiation and organization. In view of this, the purpose of this study was to analyze the collagen, the major organic component of dental pulp ECM, in papillae of human tooth germs in different develo [...] pmental phases. The maxillas and mandibles of 9 human fetuses ranging from 10 to 22 weeks of intrauterine life were removed and 16 tooth germs (1 in the cap stage, 8 in the early bell stage and 7 in the late bell stage) were obtained. The pieces were processed for histological analysis and stained with hematoxylin-eosin, Masson's Trichrome and picrosirius staining technique. Both types of collagen in the dental papilla were only detected by the picrosirius staining technique under polarized light microscopy. Type III collagen was detected in all specimens. Type I collagen was present in focal areas of the dental papilla only in some specimens. In conclusion, the findings of this study showed that type III collagen is a regular component of the papillae of human tooth germs whereas type I collagen is present in a significantly lesser amount.

Ivete Jorge, Abrahão; Manoela Domingues, Martins; Emílio, Katayama; João Humberto, Antoniazzi; Angelo, Segmentilli; Márcia Martins, Marques.

183

Effects of Ion-Releasing Tooth-Coating Material on Demineralization of Bovine Tooth Enamel  

OpenAIRE

We compared the effect of a novel ion-releasing tooth-coating material that contained S-PRG (surface-reaction type prereacted glass-ionomer) filler to that of non-S-PRG filler and nail varnish on the demineralization of bovine enamel subsurface lesions. The demineralization process of bovine enamel was examined using quantitative light-induced fluorescence (QLF) and electron probe microanalyzer (EPMA) measurement. Ion concentrations in demineralizing solution were measured using inductively c...

Koji Kawasaki; Masaki Kambara

2014-01-01

184

Unusual intraosseous transmigration of impacted tooth  

Energy Technology Data Exchange (ETDEWEB)

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.

Kumar, Santosh; Urala, Arun Srinivas; Kamath, Abhay Taranath; Jayaswal, Priyanka; Valiathan, Ashima [Manipal College of Dental Sciences, Manipal (India)

2012-03-15

185

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.

186

Intermediate Charcot-Marie-Tooth disease.  

Science.gov (United States)

Charcot-Marie-Tooth (CMT) disease is a common neurogenetic disorder and its heterogeneity is a challenge for genetic diagnostics. The genetic diagnostic procedures for a CMT patient can be explored according to the electrophysiological criteria: very slow motor nerve conduction velocity (MNCV) (45 m/s). Based on the inheritance pattern, intermediate CMT can be divided into dominant (DI-CMT) and recessive types (RI-CMT). GJB1 is currently considered to be associated with X-linked DI-CMT, and MPZ, INF2, DNM2, YARS, GNB4, NEFL, and MFN2 are associated with autosomal DI-CMT. Moreover, GDAP1, KARS, and PLEKHG5 are associated with RI-CMT. Identification of these genes is not only important for patients and families but also provides new information about pathogenesis. It is hoped that this review will lead to a better understanding of intermediate CMT and provide a detailed diagnostic procedure for intermediate CMT. PMID:25326399

Liu, Lei; Zhang, Ruxu

2014-12-01

187

Equine odontoclastic tooth resorption and hypercementosis.  

Science.gov (United States)

A poorly described, painful disorder of incisor and canine teeth, variably causing periodontitis, with resorptive or proliferative changes of the calcified dental tissues, has recently been documented in aged horses. No plausible aetiopathogenesis for this syndrome has been recorded. Eighteen diseased teeth from eight horses were examined grossly and microscopically and showed the presence of odontoclastic cells by tartrate resistant acid phosphatase (TRAP) staining. A chronological sequence of odontoclastic resorption followed by hypercementosis was demonstrated and, consequently, the term equine odontoclastic tooth resorption and hypercementosis (EOTRH) is proposed for this disorder. EOTRH shares many features with similar dental syndromes described in humans and cats. An aetiological hypothesis proposes mechanical stress of the periodontal ligament as the initiating factor. PMID:19010701

Staszyk, Carsten; Bienert, Astrid; Kreutzer, Robert; Wohlsein, Peter; Simhofer, Hubert

2008-12-01

188

Submandibular swelling: tooth or salivary stone?  

Science.gov (United States)

Submandibular swelling is a common clinical disorder of the maxillo-facial region that may be one of the manifestation of several pathologic disorders including sialolithiasis. A 38-year-old woman experienced a recurrent painful swelling in the right submandibular region for seven years. The symptoms, not always meal-related, gradually became chronic and associated with dysphagia, odynophagia and fever. Ultrasonography of the salivary glands revealed a retained glandular structure and no ductal obstruction or dilatation, and orthopantomography showed the presence of a structure compatible with tooth, but these findings did not correlate with clinical scenario. Only CT dental scan identified the radiological image as a salivary stone. Sialolithiasis should always be considered in the diagnostic iter of painful submandibular swelling. A careful evaluation of recurrence and characteristics of signs and symptoms associated to the swelling can help in making the correct diagnosis and planning a proper therapeutic strategy. PMID:24025889

Capaccio, Pasquale; Marciante, Giulia Anna; Gaffuri, Michele; Spadari, Francesco

2013-01-01

189

Anomalies of tooth formation in hypohidrotic ectodermal dysplasia.  

DEFF Research Database (Denmark)

OBJECTIVE: The X-linked hypohidrotic ectodermal dysplasia (HED) is the most common type of ectodermal dysplasia. The clinical identification of possible heterozygous females can be difficult because of the varying degrees of clinical signs caused by X-chromosome inactivation. This study is the first to elaborate on anomalies of tooth formation found in a group of hemizygous males and heterozygous females with known ED1 mutations. These tooth anomalies may be used as dental biomarkers for heterozygous females, enabling an earlier diagnosis, and therefore, better treatment and genetic counselling. METHODS: Anomalies of tooth formation were examined using panoramic radiographs, dental casts and oral photographs in hemizygous males and heterozygous females who were identified by molecular genetic analysis. The results were compared to existing controls and normative data. RESULTS: All affected males had multiple missing permanent teeth and tooth malformations. The heterozygous females had a significantly higher frequency of agenesis of permanent teeth compared to normative data. The heterozygous females had an increased prevalence of tooth malformations and reduced tooth size, especially in the mesiodistal dimension. CONCLUSIONS: We conclude that observed anomalies of tooth formation may be used as dental biomarkers in the clinical identification of potentially heterozygous females. Udgivelsesdato: 2007-Jan

Lexner, Michala O; Bardow, Allan

2007-01-01

190

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

191

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

192

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

193

Axis Inhibition Protein 2 (AXIN2) Polymorphisms and Tooth Agenesis  

OpenAIRE

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

2008-01-01

194

Study on differences of radiosensitivity of human tooth enamel  

International Nuclear Information System (INIS)

To study differences of radiosensitivity of human tooth enamel, 84 tooth enamel samples from 5 subjects were separated, and irradiated with radiation dose of 5 Gy from 60Co ? rays. After irradiation each sample was measured by ESR technique. Experimental results indicate that some difference in radiosensitivity exists for teeth from each subject (coefficients of variation of each subject range from 9.3% to 14.0%). Nevertheless, the mean values for all teeth of each subject among 5 subjects agree within the range of 325.77 to 386.80. It shows that the radiosensitivity of tooth enamel is basically uniform

195

A local intercomparison study of ESR dosimetry using tooth enamel  

International Nuclear Information System (INIS)

Using electron spin resonance (ESR), tooth enamel is a possible dosimeter in case of a radiation accident. To check the present status of this technique, we conducted a local intercomparison study. We irradiated several samples of tooth enamel with a 60Co source. Three institutes in Belgium and The Netherlands recorded the ESR signal of the samples. The results of the measurements and the methods used are compared. It is concluded that ESR on tooth enamel can be a useful technique in accident dosimetry, provided further research is done. (author)

196

Study of the kinematic and load sharing properties of wormgearing with non-symmetric tooth profiles  

Science.gov (United States)

The geometry of non-symmetric tooth profiles, i.e. tooth profiles with different pressure angles on the two sides of the tooth, is studied. A feasible non-symmetric tooth profile for application in helicopter transmissions is laid out as the best compromise among several conflicting factors. The non-symmetric tooth profile is then compared with the symmetric tooth profile studied previously. Based on the detailed comparisons it is concluded that the use of the non-symmetric tooth profile would severely limit the face width of the worm, consequently reduce the number of meshing teeth and cause much higher normal load on the individual gear teeth.

Sun, D. C.; Yuan, Qin

1995-01-01

197

Dosimetric response of tooth enamel to 14 Mev neutrons.  

Science.gov (United States)

The electron paramagnetic resonance (EPR) response of tooth enamel in a monenergetic neutron beam of 14 MeV was studied, with the aim to evaluate the relative neutron to (60)Co sensitivity. Three samples of tooth enamel powder were irradiated in air. A whole tooth and a powdered sample were irradiated in a geometrical PMMA phantom, in order to simulate the real exposure of a tooth inside a human head. The measured dose in enamel was compared to the dose calculated by Monte Carlo simulation. The relative neutron to (60)Co sensitivity using different reference materials (air, water and enamel) was evaluated as well. Large differences in sensitivity values were found depending on the reference material: the obtained relative neutron to (60)Co sensitivity was 0.47+/-0.09 for enamel and 0.15+/-0.03 for water. A comparison with results in fast neutron fields is reported. PMID:15118864

Fattibene, P; Angelone, M; De Coste, V; Pillon, M

2004-07-01

198

Measuring Ankle Instability in Pediatric Charcot-Marie-Tooth Disease.  

Science.gov (United States)

Children with Charcot-Marie-Tooth disease frequently suffer ankle sprain and experience chronic ankle instability; however, no pediatric self-reported measures of chronic ankle instability exist. The aim was to modify and validate the most reliable measure of chronic ankle instability in adults: the Cumberland Ankle Instability Tool. The Cumberland Ankle Instability Tool-Youth was tested for reliability, construct validity, and sensitivity to discriminate between 104 children aged 8 to 16 years: 31 children with Charcot-Marie-Tooth disease, 31 unaffected children with a history of ankle sprains, and 42 controls. Children with Charcot-Marie-Tooth disease had lower scores compared to unaffected children with a history of sprains (?(2) = 15.10; P ankle steadiness (r s = 0.684; P Ankle Instability Tool-Youth demonstrated excellent sensitivity and construct validity, identifying chronic ankle instability as a common problem for children with Charcot-Marie-Tooth disease. PMID:23696628

Mandarakas, Melissa; Hiller, Claire E; Rose, Kristy J; Burns, Joshua

2013-11-01

199

Analysis of absorbed dose to tooth enamel for ESR dosimetry  

International Nuclear Information System (INIS)

Absorbed dose to tooth enamel was quantitatively correlated to organ doses by Monte Carlo calculations using the Electron Gamma Shower Code Version 4 for the Electron Spin Resonance (ESR) dosimetry using teeth. A region for teeth was newly added to a mathematical human model. Kerma coefficients for whole tooth and enamel part were prepared to estimate the dose to tooth enamel. Experiments were also carried out with a physical head phantom, which is made of tissue equivalent materials. Tooth samples and thermo-luminescence dosimeters (TLDs) of CaSO4 crystal were set at the teeth position in the head phantom. Addition Monte Carlo calculations were performed to verify the results of the experiments by using a Voxel-type phantom reconstructed from computed tomographic (CT) images of the physical phantom. The obtained data are to be useful for retrospective dose assessments in past radiation events by the ESR dosimetry with teeth. (author)

200

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

201

Moxel: A molar tooth voxel model for dosimetric studies  

International Nuclear Information System (INIS)

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.

202

Single-tooth replacement: factors affecting different prosthetic treatment modalities  

OpenAIRE

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 dent...

Al-Quran Firas A; Al-Ghalayini Raed F; Al-Zu'bi Bashar N

2011-01-01

203

The combination use of platelet-rich fibrin and treated dentin matrix for tooth root regeneration by cell homing.  

Science.gov (United States)

Endogenous regeneration through cell homing provides an alternative approach for tissue regeneration, except cell transplantation, especially considering clinical translation. However, tooth root regeneration through cell homing remains a provocative approach in need of intensive study. Both platelet-rich fibrin (PRF) and treated dentin matrix (TDM) are warehouses of various growth factors, which can promote cell homing. We hypothesized that endogenous stem cells are able to sense biological cues from PRF membrane and TDM, and contribute to the regeneration of tooth root, including soft and hard periodontal tissues. Therefore, the biological effects of canine PRF and TDM on periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMSCs) were evaluated respectively in vitro. Beagle dogs were used as orthotopic transplantation model. It was found that PRF significantly recruited and stimulated the proliferation of PDLSCs and BMSCs in vitro. Together, PRF and TDM induced cell differentiation by upregulating the mineralization-related gene expression of bone sialoprotein (BSP) and osteopotin (OPN) after 7 days coculture. In vivo, transplantation of autologous PRF and allogeneic TDM into fresh tooth extraction socket achieved successful root regeneration 3 months postsurgery, characterized by the regeneration of cementum and periodontal ligament (PDL)-like tissues with orientated fibers, indicative of functional restoration. The results suggest that tooth root connected to the alveolar bone by cementum-PDL complex can be regenerated through the implantation of PRF and TDM in a tooth socket microenvironment, probably by homing of BMSCs and PDLSCs. Furthermore, bioactive cues and inductive microenvironment are key factors for endogenous regeneration. This approach provides a tangible pathway toward clinical translation. PMID:25111570

Ji, Baohui; Sheng, Lei; Chen, Gang; Guo, Shujuan; Xie, Li; Yang, Bo; Guo, Weihua; Tian, Weidong

2015-01-01

204

The relat ionship between denta l fluorosis and tooth fluoride concentrat ion – A study in an endemic area  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To determine the relationship between dental fluorosis (DF severity and fluoride [F] concentration in tooth and water in DF endemic areas. Methods: Life-long residents from two DF endemic communities were studied. Forty-five extracted teeth were collected and analyzed for DF severity and tooth [F]. Thylstrup-Ferjeskov Index (TFI was used to measure DF severity and instrumental neutron activation analysis (INAA for tooth [F] concentration. Water from regional wells was also collected (n=9 and analyzed for F content using specific ion F electrode. Results: Water [F] varied between 0.2ppm and 4.7ppm. TFI scores ranged from 0 to 6; [F] from 120ppm to 2,140ppm in enamel and 304ppm to 4,800ppm in dentin. No correlation was found between DF severity and [F] in enamel (rs=0.22,p=0.15 and dentin (rs=-0.19,p=0.20, nor between water [F] and [F] in enamel (rs=-0.09,p=0.65 and dentin (rs=-0.11,p=0.56. Weak correlation between DF severity and water [F] (rs=0.38,p=0.04 was found. Linear regression analysis showed that TFI couldn’t be predicted from a linear combination of the independent variables (age, enamel and dentin [F]. When enamel, dentin and water [F] were used as independent variables in the linear regression (predict DFseverity, only water [F] showed influence in DF severity (p=0.013;t=2.67. Conclusion: Even in areas of endemic DF, tooth [F] didn’t correlate with DF severity and the relationship between water [F] and DF severity was very weak. Therefore, tooth [F] may not be a goodpredictor/indicator of DF severity.

Marc Daniel Grynpas

2011-12-01

205

Tooth structure studied using the atomic force microscope  

Science.gov (United States)

We used the atomic force microscope (AFM) to observe structure of the tooth, both rat and human. The rigidity and the surface flatness of thin sections of this mineralized tissue, allow us to attain good resolution with the AFM. As enamel contains uniquely large crystals of hydroxyapatite it can be investigated at high resolution. Tooth enamel and thin slices of undecalcified developing tooth germs from 2 - 12 day old rats were observed, embedded in acrylic resin (Lowicryl K4M). In addition, as orthophosphoric acid is widely used clinically to etch tooth enamel before restoring with composites, we studied its action at pH2 on the tooth surface during 1 hour of exposition. Hydroxyapatite crystals and collagen fibers were seen in the tooth slices observed in air, and the classical structure of the enamel was visible. The etched enamel surface under liquid, showed dramatic differences to that imaged in air. Modifications to the surface were also seen during exposure to the acid.

Kasas, Sandor; Berdal, Ariane; Celio, Marco R.

1993-06-01

206

Relationship between tooth dimensions and malocclusion  

International Nuclear Information System (INIS)

Objective: To observe the difference in dimension of teeth among adult females with and without malocclusion. Methods: The cross-sectional study was conducted at Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi, from April 2011 to April 2013, and used non-probability consecutive sampling. Mesiodistal and buccolingual crown dimensions were measured on study casts by using digital sliding caliper in 2 groups of females. Group1 had 150 subjects with normal occlusion, while Group 2 had 234 with malocclusion. Independent t test was conducted to evaluate the difference between the dimensions of teeth of the two groups. Statistical analysis was done on SPSS version 16, and p value was considered significant at 0.05. Results: Overall, the difference between the groups showed a greater tooth dimension in the malocclusion group of population compared to the normal group, and the most significant difference was observed in the mesiodistal dimension of maxillary 2nd premolar, which was 0.9+-0.6801mm greater in dimension in the malocclusion group compared to the normal group. The least difference was observed in the buccolingual dimension of the mandibular central incisor where the malocclusion group had only 0.08+-0.5247mm larger mandibular central incisors in the buccolingual dimension compared to the normal group. Conclusion: Mesiodistal and buccolingual crown dimensions were characteristically larger in the malocclusion group. (author)

207

Mechanics of microwear traces in tooth enamel.  

Science.gov (United States)

It is hypothesized that microwear traces in natural tooth enamel can be simulated and quantified using microindentation mechanics. Microcontacts associated with particulates in the oral wear medium are modeled as sharp indenters with fixed semi-apical angle. Distinction is made between markings from static contacts (pits) and translational contacts (scratches). Relations for the forces required to produce contacts of given dimensions are derived, with particle angularity and compliance specifically taken into account so as to distinguish between different abrasives in food sources. Images of patterns made on human enamel with sharp indenters in axial and sliding loading are correlated with theoretical predictions. Special attention is given to threshold conditions for transition from a microplasticity to a microcracking mode, corresponding to mild and severe wear domains. It is demonstrated that the typical microwear trace is generated at loads on the order of 1N - i.e. much less than the forces exerted in normal biting - attesting to the susceptibility of teeth to wear in everyday mastication, especially in diets with sharp, hard and large inclusive intrinsic or extraneous particulates. PMID:25484336

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

2015-03-01

208

Trace Elements in Human Tooth Enamel  

International Nuclear Information System (INIS)

The trace elements are considered to play a role in the resistance of teeth to dental caries. The exact mechanism by which they act has not yet been fully established. Estimations of trace elements have been undertaken in sound human teeth. By means of activation analysis it has been possible to determine trace element concentrations in different layers of enamel in the same tooth. The concentrations of the following elements have been determined: arsenic, antimony, copper, zinc, manganese, mercury, molybdenum and vanadium. The distribution of trace elements in enamel varies from those with a narrow range, such as manganese, to those with a broad range, such as antimony. The elements present in the broad range are considered to be non-essential and their presence is thought to result from a chance incorporation into the enamel. Those in the narrow range appear to be essential trace elements and are present in amounts which do not vary unduly from other body tissues. Only manganese and zinc were found in higher concentrations in the surface layer of enamel compared with the inner layers. The importance of the concentration of trace elements on this surface layer of enamel is emphasized as this layer is the site of the first attack by the carious process. (author)

209

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

OpenAIRE

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 cor...

Levent Nalbant; Ferhan Egilmez

2012-01-01

210

Effects of KTP Laser Bleaching on Traumatized Tooth Enamel  

Science.gov (United States)

Background: Bleaching of traumatized discolored teeth is considered an important issue in esthetic dentistry. Various methods have been introduced for bleaching, some of which may have adverse effects on soft or hard tissues of the tooth. Objectives: The objective of the study was to evaluate the effects of KTP laser bleaching on enamel of traumatized teeth. Materials and Methods: A square of 36 mm2 was chosen on the labial surface of 32 extracted teeth. The corners were drilled in order to indicate the location precisely. The shade of each sample was recorded and the teeth were divided into four groups, each with eight teeth: group A (Smartbleach with KTP laser for 30 seconds), group B (Smartbleach with G-Light for 5 minutes), group C (only Smartbleach for 10 minutes) and group D (control group with no bleaching). After one session of bleaching, shade assessment was performed again. In another experiment on nine teeth, Smartbleach with KTP laser was used for 150 seconds to 1500 seconds. The samples were critically processed and observed by using scanning electron microscope (SEM) to assess enamel damage. Data was statistically analyzed using Kruskal-Wallis test (confidence interval level were set at 95%). Results: Smartbleach was highly effective when used with KTP laser (P = 0.0419). Enamel damage was observed after frequent KTP bleaching and 750 seconds of KTP bleaching was recognized as the limit by morphological evaluation via SEM, indicating a major difference between under and over 750 seconds of bleaching. Conclusions: Application of KTP laser may increase the bleaching effect of Smartbleach, nevertheless it may cause some enamel damage. PMID:25032154

Kinoshita, Jun-Ichiro; Jafarzadeh, Hamid; Manabe, Atsufumi; Nozawa, Miki; Uchida, Tokiko; Abbott, Paul Vincent

2014-01-01

211

Shading of ceramic crowns using digital tooth shade matching devices.  

Science.gov (United States)

In the 1990s, there was great optimism due to the development of devices for measuring tooth shade. The frequently not so simple, visual determination of the shade of a tooth was to be done with the aid of a device which recognizes the shade and describes it accurately by reference to a color chart. However, the skepticism towards such devices was also great. It is known that the color effect frequently differs strongly when comparing a tooth from the shade guide with a metal ceramic crown, despite identical shade designation. Anyone who considers visual shade determination to be inadequate and places his hopes in digital shade matching devices will be disappointed. It is the shade-generating structures of the metal ceramic and frequently of the veneer layers that turn out to be too thin which, despite correct shade selection, cause a different color perception. Such problems have been reduced decisively with the development of fracture-proof hard porcelain caps (Vita In-Ceram) with optical characteristics similar to teeth. In addition, the Vita System 3D-Master tooth shade system developed in 1998 by Vita in cooperation with Dr. Hall from Australia, leads the practitioner to a better understanding of the primary tooth shade characteristics of "brightness (value)", "color intensity (chroma)" and "color (wave length of the visible light, hue)". These two innovations allow a more accurate estimate of the basic shade of a natural tooth (reference tooth) and the imitation in the laboratory of its natural, shade-generating structures. If digital shade measurement supplements the visual shade estimate, then a further improvement can be expected--especially in the recognition of the basic shade. Qualitative descriptions of subjective shade measurement of a natural tooth and of its imitation in the dental laboratory by ceramics can be found frequently in professional journals and publications. With digital tooth shade matching devices, which apart from the color code of the color chart also reproduce exact, colorimetric values, such work processes can be recorded quantitatively and objectively. Reports about this type of controlled shade determination and generation are found rarely in the literature, which is surprising in view of the large number of tooth shade matching devices and dental ceramic systems available. In the present paper, the influence of the individual ceramic layers on color perception is measured and described under standardized conditions. The creation of the basic shade as it results from the composition of the various ceramic layers is traced with a spectrophotometer. The Vita In-Ceram Alumina infiltration ceramic and the VitaVM7 veneer ceramic were selected as the ceramic system. MHT-SpectroShade and Vita Easyshade were used as shade matching devices. PMID:16201397

Baltzer, A; Kaufmann-Jinoian, V

2005-04-01

212

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.

1791-17-01

213

Effects of ion-releasing tooth-coating material on demineralization of bovine tooth enamel.  

Science.gov (United States)

We compared the effect of a novel ion-releasing tooth-coating material that contained S-PRG (surface-reaction type prereacted glass-ionomer) filler to that of non-S-PRG filler and nail varnish on the demineralization of bovine enamel subsurface lesions. The demineralization process of bovine enamel was examined using quantitative light-induced fluorescence (QLF) and electron probe microanalyzer (EPMA) measurement. Ion concentrations in demineralizing solution were measured using inductively coupled plasma atomic (ICP) emission spectrometry and an ion electrode. The nail varnish group and the non-S-PRG filler group showed linear demineralization. Although the nail varnish group and the non-S-PRG filler group showed linear demineralization, the S-PRG filler group did not. Further, plane-scanning by EPMA analysis in the S-PRG filler group showed no changes in Ca ion distribution, and F ions showed peak levels on the surface of enamel specimens. Most ions in the demineralizing solution were present at higher concentrations in the S-PRG filler group than in the other two groups. In conclusion, only the S-PRG filler-containing tooth-coating material released ions and inhibited demineralization around the coating. PMID:24578706

Kawasaki, Koji; Kambara, Masaki

2014-01-01

214

Laser assisted tooth replantation case report  

OpenAIRE

Background and aim: Although intentional replantation for extraoral treatment is a solution for complicated endodontic cases, it is accompanied with risk of root resorption which is most likely due to extraction trauma and infected remnants. Laser therapies have long been proved for bactericidal and biostimulation effects. In the present case, a pulpitis combined severe periodontal destruction molar was extracted with an Er:YAG laser for thorough degranulation and disinfection. Before the ext...

Lu, Cheng Hsiang; Lu, Hung Chieh; Ke, Jyuhn H.; Lan, Wan Hong

2011-01-01

215

The challenges of treating a fused tooth  

Scientific Electronic Library Online (English)

Full Text Available Este caso descreve o tratamento multidisciplinar de um incisivo lateral superior permanente fusionado a um dente supranumerário, ambos apresentando necrose pulpar e lesão periapical. Paciente compareceu ao consultório se queixando de dor, edema e mobilidade do incisivo lateral superior. O preparo en [...] dodôntico foi realizado no sentido coroa-ápice e foi colocada pasta de hidróxido de cálcio como medicação intra-canal por 15 dias. A seguir, a obturação foi realizada pela termoplastificação da guta-percha. Após 18 meses, foram realizados exames clínicos e radiográficos indicando ausência de dor e edema. Dois anos após o tratamento endodôntico, o paciente retornou para o tratamento periodontal e estético. Nove meses depois, foi realizada tomografia computadorizada e observou-se presença de defeito periodontal e lesão periapical. Foi então indicada e planejada a cirurgia paraendodôntica. O dente supranumerário foi removido e a área de comunicação com o canal radicular do incisivo lateral foi preenchida; a loja cirúrgica foi preenchida com vidro bioativo e osso orgânico bovino desmineralizado. O tecido patológico da lesão periapical foi submetido à análise histopatológica sendo diagnosticado como cisto periapical. Um ano após a cirurgia parendodôntica, uma nova tomografia computadorizada mostrou neoformação óssea na região periapical do dente em questão. Doi anos após a cirurgia, a restauração foi trocada devido à motivos estéticos e uma radiografia periapical mostrou sucesso do tratamento (5 anos após o tratamento inicial). Um correto diagnóstico e plano de tratamento multidisciplinar é essencial para o sucesso do tratamento de dentes fusionados à dentes supranumerários. Abstract in english This paper describes and discusses the multidisciplinary treatment involving a permanent maxillary lateral incisor fused to a supernumerary tooth, both presenting pulp necrosis and periapical lesion. A 15-year-old male patient sought treatment complaining of pain, swelling and mobility on the maxill [...] ary right lateral incisor. After clinical and radiographic examination, root canal preparation was performed according to the crown-down technique and a calcium hydroxide dressing was placed for 15 days. The patient returned and the definitive endodontic filling was done with thermomechanical compaction of gutta-percha and sealer. After 18 months, clinical and radiographic examinations were carried out and no pain or swelling was reported. Two years after endodontic treatment, the patient returned for periodontal and cosmetic treatments. Nine months later, a cone-beam computed tomography (CBCT) revealed that the previously detected periodontal defect and periapical lesion were persistent. Apical endodontic surgery was indicated. The supernumerary tooth was removed, the communicating distal surface was filled and the surgical site received bioactive glass and demineralized bovine organic bone. The pathological tissue was submitted to histopathological examination and the diagnosis was periapical cyst. One year after the apical endodontic surgery, CBCT showed bone formation at maxillary lateral incisor apical area. Two years after the surgery, the restoration was replaced due to aesthetic reasons and periapical radiograph showed success after 5 years of treatment. A correct diagnosis and establishment of an adequate treatment plan resulted in a successful management of the case.

Flares, Baratto-Filho; Denise Piotto, Leonardi; Bruno Monguilhott, Crozeta; Samantha Pugsley, Baratto; Edson Alves, Campos; Flavia Sens Fagundes, Tomazinho; Tatiana Miranda, Deliberador.

216

Tooth structure and fracture strength of cavities  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O objetivo deste estudo foi avaliar, in vitro, a perda de estrutura dentária após o preparo cavitário para restaurações diretas e indiretas e sua relação com a resistência à fratura do dente. 60 pré-molares superiores humanos foram divididos em 6 grupos (n=10). Cavidades MOD para resina composta dir [...] eta (Grupos I, II e III) e cavidades "inlay" (Grupos IV, V e VI) foram preparadas mantendo dimensões padronizadas. A extensão vestíbulo-lingual da caixa oclusal foi estabelecida em 1/4 (Grupos I e IV), 1/3 (Grupos II e V) ou 1/2 (Grupos III e VI) da distância intercuspídea. Os dentes foram pesados, em uma balança de precisão, antes e após o preparo cavitário para aferir a perda de massa dentária. Os dentes preparados foram submetidos à força de compressão para determinar a resistência à fratura em uma máquina universal de ensaios sob uma velocidade de 0.5 mm/min. Os dados foram submetidos à análise de variância a dois critérios e ao teste de Tukey (alfa = 0.05). As cavidades do tipo "1/4-inlay" apresentaram maior percentual de perda de massa (9.71%) em relação às cavidades para resina composta com mesma extensão (7.07%). As cavidades do tipo "1/3-inlay" também apresentaram maior percentual de perda de massa (13.91%) quando comparada às cavidades para resina composta com a mesma extensão (10.02%). As cavidades do tipo "1/2-inlay" apresentaram 21.34% de perda de massa, enquanto as cavidades com extensão de 1/2 para resina composta apresentaram uma perda de 16.19%. As médias de resistência à fratura (em kgf) foram: GI = 187.65; GII = 143.62; GIII = 74.10; GIV = 164.22; GV = 101.92; GVI = 50.35. Diferenças estatisticamente significantes (p Abstract in english 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 (Gr [...] oups 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

José, Mondelli; Fábio, Sene; Renata Pereira, Ramos; Ana Raquel, Benetti.

217

The 4th international comparison on EPR dosimetry with tooth enamel  

International Nuclear Information System (INIS)

This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Muenchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated sample was kept as control. The doses delivered to the individual samples were unknown to the participants, who were asked to measure each sample nine times, and to report the EPR signal response, the mass of aliquots measured, and the parameters of EPR signal acquisition and signal evaluation. Critical dose and detection limit were calculated by the organizers on the basis of the calibration-curve parameters obtained at every laboratory. For calibration curves obtained by measuring every calibration sample three times, the mean value of the detection limit was 205 mGy, ranging from 56 to 649 mGy. The participants were also invited to provide the signal response and the nominal dose of their current dose calibration curve (wherever available), the critical dose and detection limit o), the critical dose and detection limit of which were also calculated by the organizers.

218

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

219

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

220

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

Directory of Open Access Journals (Sweden)

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

221

Metabolism in tooth enamel and reliability of retrospective EPR dosimetry connected with Chernobyl accident  

International Nuclear Information System (INIS)

It is shown that the results of retrospective EPR dosimetry by tooth enamel are essentially determined by the fact that tooth enamel is the mineral of biological origin. The structure of tooth enamel, properties of radiation defects and the role of metabolism in tooth enamel are discussed. It is shown that at deep metamorphic modifications tooth enamel don't save information about its radiation history. The reliability and accuracy of retrospective EPR dosimetry are discussed. Because after Chernobyl accident have passed 10 years the application of tooth enamel for reconstruction of doses which are connected with Chernobyl accident need care and additional investigations

222

Tooth regeneration: a revolution in stomatology and evolution in regenerative medicine  

OpenAIRE

A tooth is a complex biological organ and consists of multiple tissues including the enamel, dentin, cementum and pulp. Tooth loss is the most common organ failure. Can a tooth be regenerated? Can adult stem cells be orchestrated to regenerate tooth structures such as the enamel, dentin, cementum and dental pulp, or even an entire tooth? If not, what are the therapeutically viable sources of stem cells for tooth regeneration? Do stem cells necessarily need to be taken out of the body, and man...

Yildirim, Sibel; Fu, Susan Y.; Kim, Keith; Zhou, Hong; Lee, Chang Hun; Li, Ang; Kim, Sahng Gyoon; Wang, Shuang; Mao, Jeremy J.

2011-01-01

223

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

224

The development of complex tooth shape in reptiles  

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Full Text Available 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.

AbigailSaffronTucker

2014-02-01

225

Tooth wear in three ethnic groups in Sabah (northern Borneo).  

Science.gov (United States)

The prevalence and associated aetiologies of tooth wear were investigated in three ethnic groups in Sabah (Northern Borneo) using the Tooth Wear Index (TWI). The number of surfaces with enamel wear only, dentine exposed for less than a third or dentine exposed for more than a third were categorised into the TW minimal, moderate or severe respectively. A structured questionnaire was used to elicit medical/dental history, oral hygiene practices, satisfaction with body image, diet and other personal habits/details. The sample comprised of a self selected sample of 148 dental hospital attenders; 47 (32 per cent) each of ethnic Chinese and Malay and 54 (36 per cent) of ethnic Kadazan, matched for age and with a similar number of scoreable teeth per subject. Dentine exposure within the total sample was a common finding (95 per cent TW with moderate, 41 per cent TW severe). The Kadazan group had significantly (P carbonated beverages or fresh fruit intake were associated with tooth wear, but their frequency of consumption was low. The buccal and occlusal surfaces of the posterior teeth were the most severely worn. Generally, wear was greater in the upper anterior sextant compared to the lower anterior sextant, with the exception of the lower incisal edges in the Kadazan group. Tooth wear into dentine was a common occurrence, especially among the Kadazan subjects and least among the Chinese subjects. The aetiological factors associated with this tooth wear are different to those encountered in Western cultures. PMID:9023582

Milosevic, A; Lo, M S

1996-12-01

226

Erosive tooth wear: prevalence and severity in Swedish winetasters.  

Science.gov (United States)

Full-time Swedish winetasters test on average 20-50 different wines, nearly 5 days a week. As the pH of wines ranges from 3.0 to 3.6, there is a potential risk for tooth erosion. The aims of this study were to document the prevalence and severity of tooth erosion in qualified winetasters in relation to number of years of winetasting, salivary flow rate, and buffer capacity. The subjects comprised all 19 qualified winetasters (7 women and 12 men, aged 29-64 years employed in Stockholm by Vin & Sprit AB, the state-owned company marketing wines and spirits. At intraoral examination, tooth surface loss was registered and documented by photography. Salivary flow rate and buffer capacity of unstimulated and stimulated saliva were measured. Data on occupational background and dental and medical histories were collected. Fourteen subjects had tooth erosion, the severity varying from mild to extreme, mainly on the labio-cervical surfaces of maxillary incisors and canines. The severity of the erosion tended to increase with years of occupational exposure. Caries activity in all subjects was low. 14 subjects had low unstimulated salivary flow rates. It was concluded that full-time winetasting is an occupation associated with increased risk for tooth erosion. PMID:9469603

Wiktorsson, A M; Zimmerman, M; Angmar-Månsson, B

1997-12-01

227

Monte Carlo modeling of human tooth optical coherence tomography imaging  

International Nuclear Information System (INIS)

We present a Monte Carlo model for optical coherence tomography (OCT) imaging of human tooth. The model is implemented by combining the simulation of a Gaussian beam with simulation for photon propagation in a two-layer human tooth model with non-parallel surfaces through a Monte Carlo method. The geometry and the optical parameters of the human tooth model are chosen on the basis of the experimental OCT images. The results show that the simulated OCT images are qualitatively consistent with the experimental ones. Using the model, we demonstrate the following: firstly, two types of photons contribute to the information of morphological features and noise in the OCT image of a human tooth, respectively. Secondly, the critical imaging depth of the tooth model is obtained, and it is found to decrease significantly with increasing mineral loss, simulated as different enamel scattering coefficients. Finally, the best focus position is located below and close to the dental surface by analysis of the effect of focus positions on the OCT signal and critical imaging depth. We anticipate that this modeling will become a powerful and accurate tool for a preliminary numerical study of the OCT technique on diseases of dental hard tissue in human teeth. (paper)

228

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.

2012-04-01

229

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

230

Patient Discomfort Following Single-Tooth Implant Placement : A Randomized Controlled Trial of Immediate vs. Conventional Tooth Restoration  

DEFF Research Database (Denmark)

Aims: Evaluate postoperative discomfort (pain, bleeding and swelling) in single-tooth implant patients submitted to immediate or conventional tooth restoration together with assessment of treatment time. Methods: Twenty-four patients who received single-tooth maxillary dental implants were randomly assigned to an IR (Immediate Restoration) or CR (Conventional Restoration) group. In IR, an implant was inserted and a provisional tooth crown was delivered within the same session, while in CR it was delivered three months after implantation. Pain (first three days), bleeding (first day) and swelling (first seven days) were assessed using a questionnaire with Visual Analogue Scales (VAS). Results: Treatment time was longer for IR than for CR (57 ± 14 and 33 ± 8 min, respectively; p<0.0001). Mean VAS scores for pain, bleeding, and swelling were low for both groups at the first postoperative day. VAS scores for pain and swelling decreased continuously over the time period in both groups. Conclusions: The longer treatment time in IR didn't increase patients' perception of pain, bleeding and swelling, compared to CR. The impact of immediate tooth restoration on patients' esthetic outcome should be further considered.

Spin-Neto, Rubens; Pontes, Ana Emília Farias

2014-01-01

231

In phantom Dosimetric response of tooth enamel to neutrons.  

Science.gov (United States)

Electron Paramagnetic Resonance dosimetry based on tooth enamel has one important application in dose reconstruction of nuclear plant workers, where the contribution of neutrons to individual dose is often important. Evaluation of tooth enamel response to neutrons is thus an important goal. A few experimental data at thermal and fast neutron energies are available. A first evaluation of the tooth enamel relative response to 60Co in monoenergetic neutron flux of 2.8 and of 14 MeV, published elsewhere, has provided results apparently non-consistent with the results obtained at lower and higher energies. A comparison of those results in the 2.8 and 14 MeV beams with those available in the literature for other beams is reported and possible reasons for incongruities are discussed. Dose conversion factors of enamel to the water and air are also calculated and reported. PMID:15353709

Fattibene, P; Angelone, M; Pillon, M; De Coste, V

2004-01-01

232

In phantom dosimetric response of tooth enamel to neutrons  

International Nuclear Information System (INIS)

Electron Paramagnetic Resonance dosimetry based on tooth enamel has one important application in dose reconstruction of nuclear plant workers, where the contribution of neutrons to individual dose is often important. Evaluation of tooth enamel response to neutrons is thus an important goal. A few experimental data at thermal and fast neutron energies are available. A first evaluation of the tooth enamel relative response to 60Co in monoenergetic neutron flux of 2.8 and of 14 MeV, published elsewhere, has provided results apparently non-consistent with the results obtained at lower and higher energies. A comparison of those results in the 2.8 and 14 MeV beams with those available in the literature for other beams is reported and possible reasons for incongruities are discussed. Dose conversion factors of enamel to the water and air are also calculated and reported. (authors)

233

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

234

A technique to measure the absorbed dose in human tooth enamel using EPR method  

International Nuclear Information System (INIS)

The EPR spectrum of irradiated tooth enamel contains a multitude of signals that are divided into two categories of radiation-induced and radiation insensitive (native) signals. At lower doses the broad native signal obscures the radiation-induced signal. In this work attempt has been made to find a method to measure the radiation-induced signal other than peak-to-peak signal amplitude measurement. For this reason software was programmed to extract the data from EPR system. The average amplitude of the radiation-induced EPR signal which is defined between the known g-values can also be calculated using the software. The result of this calculations were considered as the EPR response for the tooth enamel samples irradiated from 100 to 500 mGy and was drawn as the calibration curve. The resulted data as compared to the peak-to-peak amplitude measurement method seems to be more reproducible and shows a better variation against the dose values

235

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

236

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

237

Three dimensional mathematical model of tooth for finite element analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. The mathematical model of the abutment tooth is the starting point of the finite element analysis of stress and deformation of dental structures. The simplest and easiest way is to form a model according to the literature data of dimensions and morphological characteristics of teeth. Our method is based on forming 3D models using standard geometrical forms (objects in programmes for solid modeling. Objective. Forming the mathematical model of abutment of the second upper premolar for finite element analysis of stress and deformation of dental structures. Methods. The abutment tooth has a form of a complex geometric object. It is suitable for modeling in programs for solid modeling SolidWorks. After analyzing the literature data about the morphological characteristics of teeth, we started the modeling dividing the tooth (complex geometric body into simple geometric bodies (cylinder, cone, pyramid,.... Connecting simple geometric bodies together or substricting bodies from the basic body, we formed complex geometric body, tooth. The model is then transferred into Abaqus, a computational programme for finite element analysis. Transferring the data was done by standard file format for transferring 3D models ACIS SAT. Results. Using the programme for solid modeling SolidWorks, we developed three models of abutment of the second maxillary premolar: the model of the intact abutment, the model of the endodontically treated tooth with two remaining cavity walls and the model of the endodontically treated tooth with two remaining walls and inserted post. Conclusion Mathematical models of the abutment made according to the literature data are very similar with the real abutment and the simplifications are minimal. These models enable calculations of stress and deformation of the dental structures. The finite element analysis provides useful information in understanding biomechanical problems and gives guidance for clinical research.

Puškar Tatjana

2010-01-01

238

Generation of gear tooth surfaces by application of CNC machines  

Science.gov (United States)

This study will demonstrate the importance of application of computer numerically controlled (CNC) machines in generation of gear tooth surfaces with new topology. This topology decreases gear vibration and will extend the gear capacity and service life. A preliminary investigation by a tooth contact analysis (TCA) program has shown that gear tooth surfaces in line contact (for instance, involute helical gears with parallel axes, worm gear drives with cylindrical worms, etc.) are very sensitive to angular errors of misalignment that cause edge contact and an unfavorable shape of transmission errors and vibration. The new topology of gear tooth surfaces is based on the localization of bearing contact, and the synthesis of a predesigned parabolic function of transmission errors that is able to absorb a piecewise linear function of transmission errors caused by gear misalignment. The report will describe the following topics: description of kinematics of CNC machines with six degrees of freedom that can be applied for generation of gear tooth surfaces with new topology. A new method for grinding of gear tooth surfaces by a cone surface or surface of revolution based on application of CNC machines is described. This method provides an optimal approximation of the ground surface to the given one. This method is especially beneficial when undeveloped ruled surfaces are to be ground. Execution of motions of the CNC machine is also described. The solution to this problem can be applied as well for the transfer of machine tool settings from a conventional generator to the CNC machine. The developed theory required the derivation of a modified equation of meshing based on application of the concept of space curves, space curves represented on surfaces, geodesic curvature, surface torsion, etc. Condensed information on these topics of differential geometry is provided as well.

Litvin, F. L.; Chen, N. X.

1994-01-01

239

Generation of gear tooth surfaces by application of CNC machines  

Science.gov (United States)

This study will demonstrate the importance of application of computer numerically controlled (CNC) machines in generation of gear tooth surfaces with new topology. This topology decreases gear vibration and will extend the gear capacity and service life. A preliminary investigation by a tooth contact analysis (TCA) program has shown that gear tooth surfaces in line contact (for instance, involute helical gears with parallel axes, worm gear drives with cylindrical worms, etc.) are very sensitive to angular errors of misalignment that cause edge contact and an unfavorable shape of transmission errors and vibration. The new topology of gear tooth surfaces is based on the localization of bearing contact, and the synthesis of a predesigned parabolic function of transmission errors that is able to absorb a piecewise linear function of transmission errors caused by gear misalignment. The report will describe the following topics: description of kinematics of CNC machines with six degrees of freedom that can be applied for generation of gear tooth surfaces with new topology. A new method for grinding of gear tooth surfaces by a cone surface or surface of revolution based on application of CNC machines is described. This method provides an optimal approximation of the ground surface to the given one. This method is especially beneficial when undeveloped ruled surfaces are to be ground. Execution of motions of the CNC machine is also described. The solution to this problem can be applied as well for the transfer of machine tool settings from a conventional generator to the CNC machine. The developed theory required the derivation of a modified equation of meshing based on application of the concept of space curves, space curves represented on surfaces, geodesic curvature, surface torsion, etc. Condensed information on these topics of differential geometry is provided as well.

Litvin, F. L.; Chen, N. X.

1994-04-01

240

Root canal treatment of mandibular second premolar tooth with taurodontism  

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUCTION Taurodontism is a morphoanatomical change in the shape of a tooth. An enlarged body of a tooth with smaller than usual roots is a characteristic feature. Internal tooth anatomy correlates with this appearance, which means that a taurodontal tooth has a large pulp chamber and apically positioned furcations. This dental anomaly may be associated with different syndromes and congenital discoders. CASE OUTLINE The case report presents the patient of a rare case of taurodontism in the mandibular second premolar with chronic periodontitis. Endodontic treatment was performed after dental history and clinical examination. Special care is required in all segments of endodontic treatment of a taurodontal tooth from the identification orifice, canal exploration, determining working length, cleaning and shaping and obturation of the root canal. Precurved K-file was used for canal exploration and location of the furcation. One mesial and one distal canal with the buccal position were identified in the apical third of the root canal. The working lengths of two canals were determined by radiographic interpretation with two K-files in each canal and verified with the apex locator. During canal instrumentation, the third canal was located in the disto-lingual position. The working length of the third canal was established using the apex locator. CONCLUSION Thorough knowledge of tooth anatomy and its variations can lead to lower percentage of endodontic failure. Each clinical case involving these teeth should be investigated carefully, clinically and radiographically to detect additional root canals. High quality radiographs from different angles and proper instrumentarium improve the quality of endodontic procedure.

Vujaškovi? Mirjana

2008-01-01

241

Determination of Double Flexible Toothed Wheel Length Function of Elasticity Module (E  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents the length determination modality of the double flexible toothed wheel from a toothed harmonic transmission having a wave generator with ?/2 phase difference, function of the material’s longitudinal elasticity module.

Daniel Vela

2010-10-01

242

Crystal structure of human tooth enamel studied by neutron diffraction  

Science.gov (United States)

Crystal structure of human tooth enamel was investigated using high-resolution neutron powder diffraction. Excellent agreement between observed and refined patterns is obtained, using the hexagonal hydroxyapatite model for the tooth enamel, where a large hydroxyl deficiency ˜70% is found in the 4e site. Rietveld refinements method combined with the difference Fourier maps have revealed, however, that the hydroxyl ions are not only disordered along the c-axis but also within the basal plane. Additional H ions located at the 6h site and forming HPO42- anions were found.

Ouladdiaf, Bachir; Rodriguez-Carvajal, Juan; Goutaudier, Christelle; Ouladdiaf, Selma; Grosgogeat, Brigitte; Pradelle, Nelly; Colon, Pierre

2015-02-01

243

Metastatic mandibular neuroblastoma: a rare cause of tooth mobility.  

Science.gov (United States)

Neuroblastoma (NBL), a malignant embryonic tumor derived from neural crest cells, is the most common tumor worldwide among children less than 1 year of age. Metastasis to the mandible is uncommon. This article reports the case of a 15-month-old male diagnosed with NBL with bone metastasis including the mandible which resulted in severe tooth mobility. Dentists or pediatricians should consider the primary or metastatic tumors of the maxillofacial region in the differential diagnosis in children presenting with premature loss of teeth related to tooth mobility. PMID:22524085

Kürklü, Esma; Emiro?lu, Halil Haldun; Kebudi, Rejin; Ozda?, Didem Oner; Ayan, Inci; Görgün, Omer; Zülfikar, Bülent; Yekeler, Ensar; Gülsüm, A K

2011-01-01

244

Tooth enamel sample preparation using alkaline treatment in ESR dosimetry  

International Nuclear Information System (INIS)

Tooth enamel sample preparation using alkaline treatment was studied and compared with traditional mechanical method in this paper. 20 adult teeth were used. Samples were placed into NaOH solution. This method requires 4-5 weeks and the enamel was separated from dentin. Experimental results show that 8M NaOH was appropriate for separating enamel from dentin and that there is no difference in background signal relative intensity between samples prepared by mechanical and by chemical methods. There is also no difference in radiosensitivity between samples prepared by two methods mentioned above. Dose response curve for tooth enamel samples isolated by 8M NaOH solution was obtained

245

Metabolism in tooth enamel and reliability of retrospective dosimetry  

International Nuclear Information System (INIS)

Most of the radiation centers in tooth enamel and bones are formed by the reactions COOH+??CO-2+H+, and CO2+e-?CO-2. These centers can be easily changed by metabolism and have a low stability in living organisms. The efficiency of CO-2 radical production by irradiation is substantially different for teeth and bones in living rat, dead rat, and teeth and bone removed from rat. It is shown that the suitability of tooth enamel for retrospective dosimetry can be evaluated from the anisotropy of its EPR signals

246

Dosimetric studies of gamma irradiated tooth enamel using XRD analyses  

International Nuclear Information System (INIS)

The structure of bovine teeth enamel before and after gamma irradiation was investigated via X-ray diffraction (XRD) analyses. The irradiation doses were conducted at the values ranging from 5 Gy to 5 kGy, respectively. Tooth enamel contains, mainly, crystals of hexagonal form. The radiation induced creation of carbonated free radicals and their concentration grew in a proportional manner to the irradiation dose resulting in a decrease in the crystallinity. In addition, the unit cell volume increases as the gamma radiation dose increases due to the increasing in a- and c-axes. Also, the strain increases giving rise to the disordering in tooth enamel samples as gamma dose increases

247

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

248

Anti Cariogenic Efficacy of Herbal and Conventional Tooth Pastes - A Comparative In-Vitro Study  

OpenAIRE

Background: An upsurge of herbal products in various catalogues of fast moving consumer goods is evident. Dental creams or pastes which have numerous brands since years, have addition of many more herbal tooth pastes. Main claim of these herbal tooth pastes being effective reduction in cavities and plaque control. Proven fact is that proper brushing with a tooth brush and tooth paste brings down the caries incidence, and there is a substantial amount of contribution made by indispensable ing...

K P, Mohankumar; N K, Priya; G S, Madhushankari

2013-01-01

249

Use of CAD/CAM in Esthetic Restoration of Badly Decayed Tooth  

OpenAIRE

Proper, intelligent use of materials and technology should be utilized for the benefit of the patient. This case report presents a patient with a badly broken premolar tooth demanding high esthetic all-ceramic restoration. Following multiple procedure tooth was restored with zirconia all ceramic restoration. Multiple procedures to save a tooth are a really worthy, in the interest of patients. Use of zirconia and CAD-CAM will help in saving many compromised tooth even in high-stress regions. T...

Ali Hassan Al-Faifi; Haralur, Satheesh B.

2012-01-01

250

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

OpenAIRE

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; Reza Fekrazad; Neda Shahraki

2013-01-01

251

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

Directory of Open Access Journals (Sweden)

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

252

Measurement accuracy and reliability of tooth length on conventional and CBCT reconstructed panoramic radiographs  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese INTRODUÇÃO: este estudo in vivo avaliou a precisão e a confiabilidade de medições do comprimento dentário realizadas em radiografias panorâmicas convencionais e em reconstruções panorâmicas de tomografias computadorizadas de feixe cônico (TCFC), comparando-as com medições feitas com um paquímetro [...] digital, consideradas o padrão-ouro. MÉTODOS: a amostra incluiu indivíduos que já tivessem realizado tanto exames imaginológicos de TCFC quanto radiografias panorâmicas, e cujo tratamento ortodôntico exigisse a extração de pré-molar superior. No total, 48 dentes extraídos, de 26 pacientes, foram mensurados diretamente com paquímetros digitais. As radiografias foram escaneadas e digitalmente avaliadas com a ajuda do software Dolphin 3D. Por meio da análise de variância simples com correção de Bonferroni e Coeficiente de Correlação Intraclasse simples, comparou-se a precisão das medições de comprimento dentário realizadas em reconstruções panorâmicas de TCFC, em radiografias panorâmicas convencionais e com paquímetro digital. RESULTADOS: medições repetidas de comprimento dentário feitas com o paquímetro digital, radiografias panorâmicas e reconstruções panorâmicas de TCFC foram todas consideradas, individualmente, altamente confiáveis. Em comparação ao paquímetro, as medidas obtidas por meio de radiografias panorâmicas convencionais foram, em média, 6,3 ± 2,0mm mais longas, enquanto as medidas obtidas por meio das reconstruções panorâmicas de TCFC foram, em média, 1,7 ± 1,2mm mais curtas. CONCLUSÕES: em comparação com o real comprimento dentário, as radiografias panorâmicas convencionais foram relativamente imprecisas e superestimaram o comprimento em 29%; já as reconstruções panorâmicas de TCFC subestimaram o comprimento em 4%. Abstract in english INTRODUCTION: This in vivo study assessed accuracy and reliability of tooth length measurements obtained from conventional panoramic radiographs and CBCT panoramic reconstructions to that of a digital caliper (gold standard). METHODS: The sample consisted of subjects who had CBCT and conventio [...] nal panoramic radiographic imaging and who required maxillary premolar extraction for routine orthodontic treatment. A total of 48 teeth extracted from 26 subjects were measured directly with digital calipers. Radiographic images were scanned and digitally measured in Dolphin 3D software. Accuracy of tooth length measurements made by CBCT panoramic reconstructions, conventional panoramic radiographs and digital caliper (gold standard) were compared to each other by repeated measures one-way ANOVA with Bonferroni correction and by single measures intraclass correlation coefficient. RESULTS: Repeated root length measures with digital calipers, panoramic radiographs and CBCT constructed panoramic-like images were all individually highly reliable. Compared to the caliper (gold standard), tooth measurements obtained from conventional panoramic radiographs were on average 6.3 mm (SD = 2.0 mm) longer, while tooth measurements from CBCT panoramic reconstructions were an average of 1.7 mm (SD = 1.2 mm) shorter. CONCLUSIONS: In comparison to actual tooth lengths, conventional panoramic radiographs were relatively inaccurate, overestimating the lengths by 29%, while CBCT panoramic reconstructions underestimated the lengths by 4%.

Carlos, Flores-Mir; Mark R, Rosenblatt; Paul W., Major; Jason P., Carey; Giseon, Heo.

2014-10-01

253

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

254

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

255

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

256

Low level laser can be a novel adjuvant method for orthodontic tooth movement on postmenopausal women.  

Science.gov (United States)

Osteoporosis, a pathological state commonly saw on postmenopausal women, has shown to affect jaw bone and the periodontium. While more and more adult patients seeking orthodontic treatment for a beautiful smile, the current strategy has not work well for extraction space closure in postmenopausal women with osteoporosis and concurrent bisphosphates taken. A new and non-invasive method is hoped to make a beginning. There are ample evidences showing low level laser has favorable effects on pain relief and wound healing procedure of hard and soft tissue. These effects are due to its ability to stimulate cell metabolism, angiogenesis, bone formation and osteoclastogenesis. The hypothesis we proposed herein is that low level laser may be a valuable adjuvant method for protecting and facilitating orthodontic tooth movement on this kind of patients. PMID:21194847

Chen, Yijia; Cao, Zhensheng; Zhang, Lin; Xu, Xiaomei; Chen, Yuxue; Chen, Yangxi

2011-04-01

257

Displaced lower third molar tooth into the submandibular space: Two case reports  

Science.gov (United States)

The aim of this article is to emphasize that the accidental displacement of a lower third molar during extraction is a rare, but potentially serious complication. We present two case reports on a lower third molar tooth dislodged into the submandibular space following its removal from the sockets and the subsequent management of this rare complication. Differences in the direction of displacement, the size of fragment, delay in retrieval, and tissue reactions can all influence this potential serious complication and hence no one technique is uniformly applicable. Though a rare complication, clinicians must be aware of possible lower third molars dislodgement into tissue spaces and the necessity to initiate prompt and appropriate management. PMID:25097443

Kose, Ibrahim; Koparal, Mahmut; Güne?, Nedim; Atalay, Yusuf; Yaman, Ferhan; Atilgan, Serhat; Kaya, Gurkan

2014-01-01

258

Displaced lower third molar tooth into the submandibular space: Two case reports.  

Science.gov (United States)

The aim of this article is to emphasize that the accidental displacement of a lower third molar during extraction is a rare, but potentially serious complication. We present two case reports on a lower third molar tooth dislodged into the submandibular space following its removal from the sockets and the subsequent management of this rare complication. Differences in the direction of displacement, the size of fragment, delay in retrieval, and tissue reactions can all influence this potential serious complication and hence no one technique is uniformly applicable. Though a rare complication, clinicians must be aware of possible lower third molars dislodgement into tissue spaces and the necessity to initiate prompt and appropriate management. PMID:25097443

Kose, Ibrahim; Koparal, Mahmut; Güne?, Nedim; Atalay, Yusuf; Yaman, Ferhan; Atilgan, Serhat; Kaya, Gurkan

2014-07-01

259

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)

260

Diagnostics of power transmissions system with tooth gear  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents results of laboratory tests that were aimed at detecting early stages of various faults in toothed wheels by measurement and analysis of transverse vibration speed of the transmission gear shafts. In experimental investigation, cracking of the root tooth and chipping of the tooth were detected. The laser vibrometer Ometron VH300+ was used for non-contact measurement of shaft transversal vibration speed. Gear vibrations were recorded in selected points of gear housing and gear shafts at different speeds and gear loads. Results were analyzed and compared but in this paper is presented only selected examples. This paper shows that on the basis of the transverse vibration speed of transmission gear shafts, it is possible to detect defects at an earlier stage than on the basis of the housing vibration accelerations. In the case of measuring gear shaft vibration velocity, the way of the signal generated by the defect of a gear wheel (or bearing is shortened as well as the influence of composed transmittance of the bearing-gear housing system is eliminated. WV time-frequency analysis and complex continuous wavelet transformations were used for detection. The authors introduced a measure of local tooth damage, which was proportional to the size of damage. The results of research presented in this paperconfirmed that the defect's measure is very sensitive to the development of teeth faults.

Grzegorz WOJNAR

2008-01-01

261

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

262

On hydromagnetic channel flow induced by tooth pulses  

International Nuclear Information System (INIS)

The paper considers unsteady hydromagnetic flow in a channel when the induced magnetic field is not necessarily negligible. The unsteadiness is sustained by velocity tooth pulses applied at one wall of the channel. The skin friction at the wall is compared with the situation when the induced magnetic field is neglected. (author). 3 refs, 2 tabs

263

Identification of a research protocol to study orthodontic tooth movement  

Directory of Open Access Journals (Sweden)

Full Text Available Aim: The orthodontic movement is associated with a process of tissue remodeling together with the release of several chemical mediators in periodontal tissues. Each mediator is a potential marker of tooth movement and expresses biological processes as: tissue inflammation and bone remodeling. Different amounts of every mediator are present in several tissues and fluids of the oral cavity. Therefore, there are different methods that allow sampling with several degrees of invasiveness. Chemical mediators are also substances of different molecular nature, and multiple kind of analysis methods allow detection. The purpose of this study was to draft the best research protocol for an optimal study on orthodontic movement efficiency. Methods: An analysis of the international literature have been made, to identify the gold standard of each aspect of the protocol: type of mediator, source and method of sampling and analysis method. Results: From the analysis of the international literature was created an original research protocol for the study and the assessment of the orthodontic movement, by using the biomarkers of the tooth movement. Conclusions: The protocol created is based on the choice of the gold standard of every aspect already analyzed in the literature and in existing protocols for the monitoring of orthodontic tooth movement through the markers of tooth movement. Clinical trials re required for the evaluation and validation of the protocol created.

Annalisa Dichicco

2014-06-01

264

Metamorphic modifications and EPR dosimetry in tooth enamel  

International Nuclear Information System (INIS)

It is shown that metamorphic modifications in tooth enamel have an essential influence on the result of EPR dosimetry. The metamorphic modifications in minerals of biological origin proceed more quickly than in usual natural minerals. The approaches which at present are applied for reconstruction of doses connected with Chernobyl accident need additional investigation. (Author)

265

The homology and phylogeny of chondrichthyan tooth enameloid.  

Science.gov (United States)

A systematic SEM survey of tooth microstructure in (primarily) fossil taxa spanning chondrichthyan phylogeny demonstrates the presence of a superficial cap of single crystallite enameloid (SCE) on the teeth of several basal elasmobranchs, as well as on the tooth plates of Helodus (a basal holocephalan). This suggests that the epithelial-mesenchymal interactions required for the development of enameloid during odontogenesis are plesiomorphic in chondrichthyans, and most likely in toothed gnathostomes, and provides phylogenetic support for the homology of chondrichthyan and actinopterygian enameloid. Along the neoselachian stem, we see a crownward progression, possibly modulated by heterochrony, from a monolayer of SCE lacking microstructural differentiation to the complex triple-layered tooth enameloid fabric of neoselachians. Finally, the occurrence of fully-differentiated neoselachian enameloid microstructure (including compression-resistant tangle fibered enameloid and bending-resistant parallel fibered enameloid) in Chlamydoselachus anguineus, a basal Squalean with teeth that are functionally "cladodont," is evidence that triple-layered enameloid microstructure was a preadaption to the cutting and gouging function of many neoselachian teeth, and thus may have played an integral role in the Mesozoic radiation of the neoselachian crown group. PMID:17146771

Gillis, J Andrew; Donoghue, Philip C J

2007-01-01

266

Effectiveness of LANAP over time as measured by tooth loss.  

Science.gov (United States)

This study examines the effectiveness of the laser-assisted new attachment procedure (LANAP) as measured by tooth loss, comparing data to published studies using conventional surgical treatment modalities for the primary treatment of Types III and IV periodontitis. Retrospective data from 107 patients presenting with Types III and IV periodontitis were gathered and evaluated. All patients received LANAP periodontal therapy as their primary surgical treatment according to the FDA-cleared LANAP protocol. The patients averaged 6.2 years post-treatment. The data were compared to several published studies for outcome classification and tooth loss over time. The effectiveness of LANAP as a primary treatment method for Types III and IV periodontitis compares very favorably with conventional surgical treatment modalities concerning tooth loss and stability over time, need for surgical retreatment, and outcome classification. Dentistry continues to develop less invasive means of providing patient care without sacrificing results. Less invasive treatment of periodontitis, with reduced postoperative morbidity yet equal results in tooth retention over time is an important goal. LANAP treatment for moderate and advanced periodontitis provides a less invasive treatment alternative for the dentist and patient to consider as a part of informed consent. PMID:22414508

Tilt, Lloyd V

2012-01-01

267

Caspase-7 tooth germ and hair follicle development and maintenance.  

Czech Academy of Sciences Publication Activity Database

Rome : ECDO, 2012. 257-257. [Euroconference from Death to Eternity /20./ and Training course on Concepts and Methods in Programmed Cell Death /9./. 14.09.2012-17.09.2012, Rome] R&D Projects: GA ?R(CZ) GAP502/12/1285 Institutional support: RVO:67985904 Keywords : caspase-7 * hair follicle * tooth germ Subject RIV: EA - Cell Biology

Veselá, Barbora; Matalová, Eva

268

High spatial resolution with zoomable saw-tooth refractive lenses?  

Science.gov (United States)

Refractive x-ray lenses can be assembled from two opposing saw-tooth structures, when they are inclined with respect to each other and almost touch at one end. An incident plane wave will then traverse a varying number of triangular prisms, which direct the beam towards the optical axis and focus it. Optically speaking the plane wave traverses a parabolic lens profile, which is approximated by trapezoidal segments. The parabolic profile will focus ideally, when a lens can be discussed in the "thin lens" approximation. Now the saw-tooth refractive lens is found to be too "thick". The residual aberrations limit the focusing capability to just submicrometer focusing, significantly above the limit in diffraction limited focusing. It is shown that the aberrations can be removed by introducing a variation into the originally constant saw-tooth angle. After this modification the lens can be operated in the diffraction limited regime. Spot sizes even below 0.1 micrometer are then feasible. This performance in terms of spatial resolution is found to be limited to focusing to microspots and is not available, when the saw-tooth refractive lens is used in an imaging setup. In this case the spatial resolution deteriorates rapidly with increasing off axis distance of the object to be imaged.

Jark, Werner

2011-09-01

269

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

270

Causes of Charcot-Marie-Tooth Disease (CMT)  

Science.gov (United States)

... cord with the rest of the body. The peripheral nerve fibers, called axons , extend from sensory nerve cells in the body's ... Tooth disease (CMT). In different types of CMT, peripheral nerve damage can ... for proteins affecting axons, or by defects in genes coding for proteins ...

271

Tooth agenesis: from molecular genetics to molecular dentistry.  

Czech Academy of Sciences Publication Activity Database

Ro?. 87, ?. 7 (2008), s. 617-623. ISSN 0022-0345 R&D Projects: GA AV ?R KJB500450802; GA MŠk OC B23.001; GA ?R GC524/08/J032 Institutional research plan: CEZ:AV0Z50450515 Keywords : tooth agenesis Subject RIV: FF - HEENT, Dentistry Impact factor: 3.142, year: 2008

Matalová, Eva; Fleischmannová, Jana; Sharpe, P. T.; Tucker, A. S.

2008-01-01

272

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

273

Seal Out Tooth Decay: A Fact Sheet for Parents  

Science.gov (United States)

Seal Out Tooth Decay A Fact Sheet for Parents National Institute of Dental and Craniofacial Research What are dental sealants? Sealants are thin, plastic coatings painted on the chewing surfaces of the back teeth. Sealants are put on in dentists’ offices, clinics, and ...

274

Hair keratin mutations in tooth enamel increase dental decay risk.  

Science.gov (United States)

Tooth enamel is the hardest substance in the human body and has a unique combination of hardness and fracture toughness that protects teeth from dental caries, the most common chronic disease worldwide. In addition to a high mineral content, tooth enamel comprises organic material that is important for mechanical performance and influences the initiation and progression of caries; however, the protein composition of tooth enamel has not been fully characterized. Here, we determined that epithelial hair keratins, which are crucial for maintaining the integrity of the sheaths that support the hair shaft, are expressed in the enamel organ and are essential organic components of mature enamel. Using genetic and intraoral examination data from 386 children and 706 adults, we found that individuals harboring known hair disorder-associated polymorphisms in the gene encoding keratin 75 (KRT75), KRT75(A161T) and KRT75(E337K), are prone to increased dental caries. Analysis of teeth from individuals carrying the KRT75(A161T) variant revealed an altered enamel structure and a marked reduction of enamel hardness, suggesting that a functional keratin network is required for the mechanical stability of tooth enamel. Taken together, our results identify a genetic locus that influences enamel structure and establish a connection between hair disorders and susceptibility to dental caries. PMID:25347471

Duverger, Olivier; Ohara, Takahiro; Shaffer, John R; Donahue, Danielle; Zerfas, Patricia; Dullnig, Andrew; Crecelius, Christopher; Beniash, Elia; Marazita, Mary L; Morasso, Maria I

2014-12-01

275

Comparative Study of Streptococcus mutans Laboratory Strains and Fresh Isolates from Carious and Caries-Free Tooth Surfaces and from Subjects with Hereditary Fructose Intolerance  

OpenAIRE

This study was undertaken to investigate and compare some biochemical and physiological properties related to sugar metabolism of 4 laboratory strains and 13 freshly isolated strains of Streptococcus mutans from carious and caries-free tooth surfaces and from subjects with hereditary fructose intolerance. Growth in Trypticase (BBL Microbiology Systems)-yeast extract in the presence of various sugars was almost the same for all of the fresh isolates, which grew generally better than the labora...

Vadeboncoeur, Christian; Trahan, Luc

1983-01-01

276

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

277

Tooth engineering: searching for dental mesenchymal cells sources.  

Science.gov (United States)

The implantation of cultured re-associations between embryonic dental mesenchymal cells and epithelial cells from mouse molars at embryonic day 14 (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. PMID:21483728

Keller, Laetitia; Kuchler-Bopp, Sabine; Mendoza, Soledad Acuña; Poliard, Anne; Lesot, Hervé

2011-01-01

278

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

International Nuclear Information System (INIS)

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

279

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

280

In vitro color change of three dental veneering resins in tea, coffee and tamarind extracts  

OpenAIRE

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...

Muttagi, S.; Subramanya, J. K.

2011-01-01

281

Selection of instruments for the successful extraction of molar teeth: a pilot study.  

Science.gov (United States)

We report the result of a pilot study that was designed to test the effectiveness of a chart that gives advice about the choice of extraction instruments and the techniques necessary to remove molar teeth successfully. It was designed from experience gained from the extraction of several molar teeth under local anaesthesia, and includes 20 blocks that cover a combination of five clinical presentations of tooth decay with four clinical presentations of tooth mobility. Recent graduates who used the chart were able to extract more molar teeth successfully than those who did not, and its use can also reduce the amount of supervision time necessary without compromising the guidance required. PMID:18547693

Babarinde, Bolaji Adebayo

2009-01-01

282

Effect of the Simulated Disinfection by Microwave Energy on the Impact Strength of the Tooth/Acrylic Resin Adhesion  

OpenAIRE

The objective of this study was to determine the effect of simulated microwave disinfection on the tooth/acrylic resin impact strength. Acrylic molar teeth with a wax stick attached to the ridge lap were included in brass flasks. Specimens were made with Classico thermopolymerized acrylic resin, according to the groups: 1 and 5 - tooth with no treatment (control); 2 and 6 – tooth bur abrasion; 3 and 7 – tooth bur retention; and 4 and 8 – tooth monomer etch. Eighty specimens (n=10) were ...

Consani, Rafael L. X.; Mesquita, Marcelo F.; Zampieri, Marinaldo H.; Mendes, Wilson B.; Consani, Simonides

2008-01-01

283

Assessment of performance parameters for EPR dosimetry with tooth enamel  

International Nuclear Information System (INIS)

In the framework of a comparison between three laboratories, electron paramagnetic resonance (EPR) signal-to-dose response curves were measured for sets of 30 tooth enamel samples and the variance of EPR measurements in dependence on absorbed dose was evaluated, in nine combinations of laboratory of sample preparation and EPR evaluation, respectively. As a test for benchmarking of EPR evaluation, the parameters 'critical dose' and 'limit of detection' were proposed as performance parameters following definitions from chemical-metrology, and a model function was suggested for analytical formulation of the dependence of the variance of EPR measurement on absorbed dose. First estimates of limits of detection by weighted and unweighted fitting resulted in the range 101-552 and 67-561 mGy, respectively, and were generally larger with weighted than with unweighted fitting. Indication was found for the influence of methodology of sample preparation and applied EPR measurement parameters on performance of EPR dosimetry with tooth enamel

284

Impact of Local Application of Clindamycin in Preventing Dry Socket after Third Mandibular Molar Extraction  

OpenAIRE

Extraction of third mandibular tooth is one of the most commonly performed surgical procedures in oral surgery. One of the most common complications following the extraction of third mandibular molar teeth is dry socket (alveolar osteitis). Dry socket is the delayed healing of the wound of the alveolar bone after dental extractions. The purpose of this study was to determine if the intra-alveolar application of Clindamycin could reduce the incidence of dry socket following the extraction of t...

Vjosa Hamiti-Krasniqi; Zana Agani; Gafur Shtino; Mergime Loxha; Jehona Ahmedi; Aida Rexhepi

2014-01-01

285

Differential changes in gingival somatosensory sensitivity after painful electrical tooth stimulation.  

Science.gov (United States)

We aimed to evaluate the effect of painful tooth stimulation on gingival somatosensory sensitivity of healthy volunteers in a randomized, controlled design. Thirteen healthy volunteers (six women, seven men; 28.4 ± 5.0 years) were included for two experimental sessions of electrical tooth stimulation: painful tooth stimulation and tooth stimulation below the sensory threshold (control). Eight of the human subjects participated in a third session without tooth stimulation. In all sessions, the somatosensory sensitivity of the gingiva adjacent to the stimulated tooth was evaluated with a standardized battery of quantitative sensory tests (QST) before, immediately after and 30 min after tooth stimulation. Painful tooth stimulation evoked significant decreases in warmth and heat pain thresholds (P  0.086). No QST changes were detected in the session without tooth stimulation (P > 0.060). In conclusion, modest increased gingival sensitivity to warmth, painful heat and pressure stimuli as well as desensitization to non-painful mechanical stimulation were demonstrated after tooth stimulation. This suggests involvement of competing heterotopic facilitatory and inhibitory mechanisms. Furthermore, stimulation below the sensory threshold induced similar thermal sensitization suggesting the possibility of activation of axon-reflex-like mechanisms even at intensities below the perception threshold. These findings may have implications for interpretation of somatosensory results in patients with chronic intraoral pain. PMID:25567087

Baad-Hansen, Lene; Lu, Shengyi; Kemppainen, Pentti; List, Thomas; Zhang, Zhenting; Svensson, Peter

2015-04-01

286

[A semi-automatic method for tooth segmentation in dental CT images].  

Science.gov (United States)

To reconstruct a tooth model from CT slices, we need to define the accurate contour of each tooth from CT slices. In this paper, we propose a semi-automatic method for drawing the contours of teeth in dental CT images. First of all, we select the reference slice from CT slices and carry out tooth segmentation interactively based on shape characteristic of each tooth. The dental CT images have the following distinct characteristic: in two neighboring CT slices, the size, location and intensity of corresponding tooth is very similar, so we can project the bounding box of the tooth whose contour has been drawn onto the next slice as the operation region of corresponding tooth. And then we perform segmentation operation tooth by tooth in the operation region based on the region growing algorithm using the information passed from the previous slice. With the reference slice as the starting slice, we carry out tooth segmentation slice by slice like this way automatically. The test result shows that the proposed method can detect the contours of teeth quickly and reliably with only little user intervention and it has practical value. PMID:17333883

Zhang, Fei; Fan, Yubo; Pu, Fang; Liu, Zhan

2007-02-01

287

Tooth color selection and characterization accomplished with optical mapping.  

Science.gov (United States)

Due to rising patient expectations and recent developments in material composition and clinical techniques, the demand for restorations that replicate the natural dentition has increased significantly. It is imperative that clinicians and dental technicians develop the communication skills necessary to ensure predictable and reliable shade reproduction. This article defines tooth color and its optical properties while describing techniques for the accurate translation of these characteristics into a laboratory prescription form that utilizes optical mapping procedures. PMID:11405007

Priest, G; Lindke, L

2000-01-01

288

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

289

ON THE R-CURVE BEHAVIOR OF HUMAN TOOTH ENAMEL  

OpenAIRE

In this study the crack growth resistance behavior and fracture toughness of human tooth enamel were quantified using incremental crack growth measures and conventional fracture mechanics. Results showed that enamel undergoes an increase in crack growth resistance (i.e. rising R-curve) with crack extension from the outer to the inner enamel, and that the rise in toughness is function of distance from the Dentin Enamel Junction (DEJ). The outer enamel exhibited the lowest apparent toughness (0...

Bajaj, Devendra; Arola, Dwayne

2009-01-01

290

Endodontic Treatment of a Taurodontism Tooth: Report of a Case  

OpenAIRE

Taurodontism is a rare dental anomaly in which the involved tooth has an enlarged and elongated body and pulp chamber with apical displacement of the pulpal floor. Endodontic treatment of these teeth is challenging, because it is hard to identify the number of root canals. In this article a case of bilateral involvement of maxillary first molars is presented. Endodontic treatment of right maxillary first molar with taurodontism was indicated due to irreversible pulpitis. This article describe...

Nazari, Shahrzad; Mirmotalebi, Farshid

2006-01-01

291

An interdisciplinary approach to treat crown-root-fractured tooth  

OpenAIRE

Restoration of a crown-root subgingival fractured tooth, especially at anterior aesthetic zones is still a great challenge for restorative dentists. Crown lengthening procedure alone has the disadvantage of high gingival curve of the final restoration, which was not discontinuous to adjacent teeth and thus compromise cosmetic outcomes. The objective of this report is to display a new interdisciplinary approach which combining endodontic root canal treatment, orthodontic extrusion, periodontal...

Sun, Ying Chun; Li, Ying; Tong, Jian; Gao, Ping

2013-01-01

292

Morphology and function of maturation ameloblasts in kitten tooth germs.  

OpenAIRE

In order to clarify the morphology and function of maturation ameloblasts, kitten tooth germs were examined using an ultrastructural tracer technique. Kitten maturation ameloblasts were divided into two cell types: a ruffle-ended type showing plasma membrane infoldings and invaginations at the distal cell surface and a smooth-ended type showing a non-invaginated, smooth distal cell surface. Both ameloblasts possessed two sets of junctional complexes at their proximal and distal ends. In eithe...

Sasaki, T.

1984-01-01

293

Towards Unraveling the Human Tooth Transcriptome: The Dentome  

Science.gov (United States)

The goal of the study was to characterize the transcriptome profiles of human ameloblasts and odontoblasts, evaluate molecular pathways and advance our knowledge of the human “dentome”. Laser capture microdissection was used to isolate odontoblasts and ameloblasts from human tooth buds (15-20week gestational age) from 4 fetuses. RNA was examined using Agilent 41k whole genome arrays at 2 different stages of enamel formation, presecretory and secretory. Probe detection was considered against the array negative control to control for background noise. Differential expression was examined using Significance Analysis of Microarrays (SAM) 4.0 between different cell types and developmental stages with a false discovery rate of 20%. Pathway analysis was conducted using Ingenuity Pathway Analysis software. We found that during primary tooth formation, odontoblasts expressed 14,802 genes, presecretory ameloblasts 15,179 genes and secretory ameloblasts 14,526 genes. Genes known to be active during tooth development for each cell type (eg COL1A1, AMELX) were shown to be expressed by our approach. Exploring further into the list of differentially expressed genes between the motile odontoblasts and non-motile presecretory ameloblasts we found several genes of interest that could be involved in cell movement (FN1, LUM, ASTN1). Furthermore, our analysis indicated that the Phospholipase C and ERK5 pathways, that are important for cell movement, were activated in the motile odontoblasts. In addition our pathway analysis identified WNT3A and TGFB1 as important upstream contributors. Recent studies implicate these genes in the development of Schimke immuno-osseous dysplasia. The utility of laser capture microdissection can be a valuable tool in the examination of specific tissues or cell populations present in human tooth buds. Advancing our knowledge of the human dentome and related molecular pathways provides new insights into the complex mechanisms regulating odontogenesis and biomineralization. This knowledge could prove useful in future studies of odontogenic related pathologies. PMID:25849153

2015-01-01

294

Molar tooth development in caspase-3 deficient mice.  

Czech Academy of Sciences Publication Activity Database

Ro?. 50, 5 (2006), s. 491-497. ISSN 0214-6282 R&D Projects: GA AV ?R KJB500450503; GA MŠk OC B23.001 Grant ostatní: European Molecular Biology Organization ASTF195.00-05; NIH NS41962 Institutional research plan: CEZ:AV0Z50450515 Keywords : tooth development * dental apoptosis * caspase-3 mutant Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.577, year: 2006

Matalová, Eva; Sharpe, P. T.; Lakhani, S. A.; Roth, K. A.; Flavell, R. A.; Šetková, Jana; Míšek, Ivan; Tucker, A. S.

2006-01-01

295

Contemporary management of tooth replacement in the traumatized dentition  

Science.gov (United States)

Dental trauma can result in tooth loss despite best efforts at retaining and maintaining compromised teeth (Dent Traumatol, 24, 2008, 379). Upper anterior teeth are more likely to suffer from trauma, and their loss can result in significant aesthetic and functional problems that can be difficult to manage (Endod Dent Traumatol, 9, 1993, 61; Int Dent J 59, 2009, 127). Indeed, teeth of poor prognosis may not only present with compromised structure but trauma may also result in damage to the support tissues. Injury to the periodontium and alveolus can have repercussions on subsequent restorative procedures (Fig. 19). Where teeth are identified as having a hopeless prognosis either soon after the incident or at delayed presentation; planning for eventual tooth loss and replacement can begin at the early stages. With advances in both adhesive and osseointegration technologies, there are now a variety of options for the restoration of edentate spaces subsequent to dental trauma. This review aims to identify key challenges in the provision of tooth replacement in the traumatized dentition and outline contemporary methods in treatment delivery. PMID:22494549

Alani, Aws; Austin, Rupert; Djemal, Serpil

2012-01-01

296

A radiological study on the tooth shape anomaly  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to evaluate the prevalence and distribution according to the types of tooth shape anomalies in permanent teeth of 6,082 persons by means of analysis of the full mouth periapical radiographs. And the following results were obtained ; 1. Among tooth shape anomalies, the highest incidence was observed on dilaceration (20.14%), followed by dens invaginatus (3.02%), peg lateralis (1.48%), taurodontism (0.34%), dens evaginatus (0.33%), talon cusp (0.20%), fusion (0.07%) and gemination (0%) in descending order of frequency. 2. Peg lateralis, dens invaginatus and dilaceration occurred more prevalent in females, and other types of tooth shape anomalies occurred more prevalent in males. 3. Dens evaginatus and taurodontism occurred with bilateral tendency, but other anomalies occurred with unilateral tendency. 4. As to the involved teeth, maxillary lateral incisors were the most frequently involved teeth on peg lateralis, dens invaginatus and talon cusp. And the mandibular premolars were the most frequently involved teeth on dens evaginatus, the maxillary first molars were on taurodontism, the maxillary second premolars were on dilaceration, and the mandibular incisors and canines were on fusion.

Choi, Karp Shik [Dept. of Oral Radiology, College of Dentistry, Kyungpook National University, Daegu (Korea, Republic of)

1994-02-15

297

A radiological study on the tooth shape anomaly  

International Nuclear Information System (INIS)

The purpose of this study was to evaluate the prevalence and distribution according to the types of tooth shape anomalies in permanent teeth of 6,082 persons by means of analysis of the full mouth periapical radiographs. And the following results were obtained ; 1. Among tooth shape anomalies, the highest incidence was observed on dilaceration (20.14%), followed by dens invaginatus (3.02%), peg lateralis (1.48%), taurodontism (0.34%), dens evaginatus (0.33%), talon cusp (0.20%), fusion (0.07%) and gemination (0%) in descending order of frequency. 2. Peg lateralis, dens invaginatus and dilaceration occurred more prevalent in females, and other types of tooth shape anomalies occurred more prevalent in males. 3. Dens evaginatus and taurodontism occurred with bilateral tendency, but other anomalies occurred with unilateral tendency. 4. As to the involved teeth, maxillary lateral incisors were the most frequently involved teeth on peg lateralis, dens invaginatus and talon cusp. And the mandibular premolars were the most frequently involved teeth on dens evaginatus, the maxillary first molars were on taurodontism, the maxillary second premolars were on dilaceration, and the mandibular incisors and canines were on fusion.

298

Occupational tooth-wear in clothing industry workers.  

Science.gov (United States)

A research on tooth-wear was done in a clothing factory, focusing on the teeth of the inter-canine sector in 59 workers who had volunteered for the research. The subjects were in the habit of cutting the thread with their teeth instead of using scissors as was prescribed in the production process. In 53 (89.83%) of the subjects, damages of the incisal portion of the tooth were found, whereas in the remaining 6 (10.17%) there were no such changes. No significant difference could be established in the incidence of tooth-wear between the women workers who cut the thread with their teeth constantly and those who only did that occasionally (p > 0.05). Because of the action of pulling a thread across the incisal edge of the incisor, defects--in the form of solitary, oval or multiple cuts (attributed the values 1, 2 and 3)--had been inflicted on the incisal portion of the teeth. Most frequently those were the defects of the enamel (type 2, 1), but in some cases dentin (type 3), also was affected. A somewhat more severe degree of damage was observed from workers biting the purely polyester-made thread (p sewing type of thread. Education of the workers seems to be the only useful prevention, since we are dealing with only a bad habit. Therefore, the workers should be warned that the seemingly innocent cutting of thread with their teeth could lead to esthetic, functional and restorative problems. PMID:9951170

Prpi?-Mehici?, G; Buntak-Kobler, D; Juki?, S; Katunari?, M

1998-12-01

299

Ultrasonic scaler oscillations and tooth-surface defects.  

Science.gov (United States)

Damage to tooth root surfaces may occur during ultrasonic cleaning with both piezoelectric and magnetostrictive ultrasonic scalers. It is unclear which mechanism causes more damage or how their mechanism of action leads to such damage. Our null hypothesis is that tooth-surface defect dimensions, resulting from instrumentation with ultrasonic scalers, are independent of whether the scaler probe is magnetostrictive or piezoelectric. Piezoelectric and magnetostrictive ultrasonic scaler probes were placed into contact against polished dentin samples (100 g/200 g). Resulting tooth surfaces were evaluated with a laser metrology system. Ultrasonic instrumentation produced an indentation directly related to the bodily movement of the probe as it made an impact on the surface. Load, generator power, and probe cross-section significantly affected probe vibration and defect depth/volume. Defect dimensions were independent of generator type. Magnetostrictive probes oscillated with greater displacement amplitudes than piezoelectric probes, but produced similar defects. This may be due to the cross-sectional shape of the probes. PMID:19329455

Lea, S C; Felver, B; Landini, G; Walmsley, A D

2009-03-01

300

[Evaluation of air-powder abrasive system on tooth abrasion].  

Science.gov (United States)

The maintenance of good oral hygiene in patients with or without prosthesis has been one of the essential parts of the total oral health care. Recently a redesigned air-powder abrasive system was introduced to remove dental plaque and stain from tooth surfaces. This study was designed to evaluate effects of this device on the cementoenamel junction area quantitatively and qualitatively by using the Michigan Computer Graphic Coordinate Measuring system (MCGCMS) and scanning electron microscopy (SEM) after exposure to an air-powder abrasive device. A tooth specimen was exposed to a Cavi-Jet (Dentsply International Inc., York, PA) for 10, 30, 90 seconds intervals. The MCGCMS was utilized before and after treatment of the specimen at each time interval to measure the depth abrasion of the tooth material, and SEM pictures were taken after 90 seconds treatment of the specimen to evaluate surface characteristics. Following conclusions were drawn within the limits the confines of this study. 1. An air-powder abrasive device abrades cementum rapidly and should be used carefully below cementoenamel junction. 2. There was no significant change on the enamel surface quantitatively. 3. The MCGCMS reproduces and measures experimental points accurately. PMID:2130133

Han, J S

1990-04-01

301

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

Directory of Open Access Journals (Sweden)

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

302

Effects of Tooth Coating Material and Finishing Agent on Bleached Enamel Surfaces by KTP Laser  

Science.gov (United States)

Objective: The purpose of this study was to evaluate the effect of tooth coating material and finishing agent on bleached enamel surfaces after using KTP laser with 27% hydrogen peroxide. Background data: There have been few reports on the effects of tooth coating materials and finishing agents after bleaching. Methods: After 40 crowns of human extracted maxillary incisors were bleached by KTP laser, bleached enamels were finished with fluoride only or both of fluoride and nano-hydroxyapatite as a finishing agent. After application(s) of fluoride and/or finishing agent, the enamel surfaces were divided into 2 groups, which were covered with the coating material or without coating material. After application of coating materials, all specimens were kept for 2 weeks at 37°C of 100% humidity. After removing the coating material, color changing was measured and enamel surfaces were examined by scanning electron microscopy (SEM). Results: SEM observation of enamel surfaces treated the fluoride gel, finishing agent and coating material showed the most flattered surface compared to other groups. By measuring the color changing, few color changing was observed on the enamel surfaces treated the fluoride gel, finishing agents and coating material. Conclusion: These results suggested that applications of fluoride gel, finishing agent and coating material made the enamel-surfaces flattered and kept effects of bleaching, could prevent the re-coloration. After applications of fluoride gel and finishing agent, covering the bleached-enamel surfaces with the coating material enhanced the keeping whiteness. It would give the patients satisfaction of whiteness. PMID:24155557

Kameda, Ayumi; Masuda, Yoshiko Murakami; Teruo, Toko; Yamada, Yoshishige; Kimura, Yuichi; Tamaki, Yukimichi; Miyazaki, Takashi

2013-01-01

303

Esthetic management of double tooth associated with talon cusp using a laminate veneer.  

Science.gov (United States)

Double tooth and talon cusp are tooth shape anomalies with rare co-occurrences in a single tooth. Double tooth is a developmental anomaly that leads to the eruption of fused teeth and may contribute to compromised esthetics, pain, caries, and tooth crowding. Talon cusp is a rare developmental extra cusp-like projection on the cingulum area that may cause functional and esthetic problems. Differential diagnosis of these anomalies may be complicated. A multidisciplinary approach for the esthetic and functional rehabilitation of double teeth is important. Various treatment methods have been described in the literature for the different types and morphological variations of double teeth. The purpose of this paper is to report the case of an unusual combination of double tooth and talon cusp on a permanent maxillary incisor and describe its esthetic and functional rehabilitation using a porcelain laminate veneer. PMID:25514262

Cordeiro, Wayne José Batista; do Couto, Cintia Fernandes; Barros, Renata Nunes; Zarranz, Laila; Jorge, Mônica Zacharias; de Gouvêa, Cresus Vínicius Depes

2015-01-01

304

Influence of pericarp, cotyledon and inhibitory substances on sharp tooth oak (Quercus aliena var. acuteserrata) germination.  

Science.gov (United States)

In order to explore the mechanism of delayed and uneven germination in sharp tooth oak (Quercus aliena var. acuteserrata) (STO), mechanical scarification techniques were used to study STO root and shoot germination and growth. The techniques used were: removing cup scar (RS), removing the pericarp (RP), and cutting off 1/2 (HC) and 2/3 (TC) cotyledons. Germination percentage and root and shoot length for Chinese cabbage (Beassica pekinensis) seeds (CCS) were also investigated for CCS cultivated in a Sanyo growth cabinet watered by distilled water and 80% methanol extracts from the acorn embryo, cotyledon and pericarp with concentrations of 1.0 g, 0.8 g, 0.6 g and 0.4 g dry acorn weight per ml methanol. The results showed that the majority of roots and shoots from acorns with RP and HC treatment emerged two weeks earlier, more simultaneously, and their total emergencies were more than 46% and 28% higher, respectively. TC accelerated root and shoot emergence time and root length, but root and shoot germination rate and shoot height had no significant difference from the control. Positive consequences were not observed on all indices of RS treatment. The germination rates of CCS watered by 1.0 g · ml(-1) methanol extracts from the embryo and cotyledon were significantly lower than those from the pericarp, and all concentrations resulted in decreased growth of root and shoot. Methanol extracts from pericarp significantly reduced root length of CCS, but presented little response in germination percentage and shoot length. The inhibitory effect was gradually increased with the increasing concentration of the methanol extract. We conclude that both the mechanical restriction of the pericarp and the presence of germination inhibitors in the embryo, cotyledon and pericarp are the causes for delayed and asynchronous germination of STO acorns. PMID:23133517

Liu, Yan; Liu, Guangquan; Li, Qingmei; Liu, Yong; Hou, Longyu; Li, Guolei

2012-01-01

305

Tooth structure removal associated with various preparation designs for posterior teeth.  

Science.gov (United States)

The amount of tooth structure removed for various innovative and conventional preparation designs for fixed prosthodontics was quantified. Four Typodont resin teeth representing maxillary and mandibular premolars and molars were prepared in various abutment designs: adhesive, box (A2); adhesive, wing and groove (A3); mesioocclusal or distoocclusal inlay; mesio-occlusodistal inlay (13); mesio-occlusodistal onlay; partial crown; half crown (only molars); complete crown, 0.8-mm circumferential tapered chamfer (F1); complete crown, 1.0-mm circumferential rounded shoulder; and complete crown, 1.4-mm axial reduction facial shoulder, 0.7-mm lingual chamfer (F3). After tooth preparation (10 per group), the root was separated from the anatomic crown at the cementoenamel junction. Removal of tooth structure was measured by gravimetric analysis in a high-precision balance. Preparations A3 and F3 were assigned as abutments for metal-supported restorations, whereas all other preparations were used for all-ceramic restorations. When the mean structure removal of all teeth tested was compared, the adhesive and inlay abutments were the least invasive preparation designs, ranging from approximately 5.5% (A2) to 27.2% (13) tooth structure removal. Complete crowns required the most invasive preparations, ranging from 67.5% (F1) to 75.6% (F3) tooth structure removal. The tooth structure removal required for F3 retainers was almost 14 times greater than for an A2 preparation. Tooth structure removal was also influenced by the morphology of the tooth. The first comprehensive tooth preparation design classification system was introduced. The measurement system used in this study provides an accurate method of quantifying tooth structure removal for fixed prosthodontic preparations. The innovative preparation designs studied conserved significant amounts of tooth structure, yielding a better prognosis for the restored tooth. PMID:12186346

Edelhoff, Daniel; Sorensen, John A

2002-06-01

306

ESR dating. Pt. 3: a study of fossils of deer and ox tooth  

International Nuclear Information System (INIS)

The ages of fossils of deer and ox tooth, from Maanshan Tongzi in Guizhou and Zhaocun Qianan in Hebei respectively have been determined by using ESR dating. The age of the deer tooth is (1.5 ± 0.2) x 104 a and that of the ox tooth is (3.7 ± 0.5) x 104 a. The property of trapped center, as the source of ESR signal, has been preliminarily established with positron annihilation technique

307

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

OpenAIRE

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...

Huysseune, Ann; Soenens, Mieke; Elderweirdt, Fien

2014-01-01

308

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

Directory of Open Access Journals (Sweden)

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

309

Acceleration of tooth movement during orthodontic treatment--a frontier in orthodontics.  

Science.gov (United States)

Nowadays, there is an increased tendency for researches to focus on accelerating methods for tooth movement due to the huge demand for adults for a shorter orthodontic treatment time. Unfortunately, long orthodontic treatment time poses several disadvantages like higher predisposition to caries, gingival recession, and root resorption. This increases the demand to find the best method to increase tooth movement with the least possible disadvantages. The purpose of this study is to view the successful approaches in tooth movement and to highlight the newest technique in tooth movement. A total of 74 articles were reviewed in tooth movement and related discipline from 1959 to 2013. There is a high amount of researches done on the biological method for tooth movement; unfortunately, the majority of them were done on animals. Cytokine, PTH, vitamin D, and RANKL/RANK/OPG show promising results; on the other hand, relaxin does not accelerate tooth movement, but increases the tooth mobility. Low-level laser therapy has shown positive outcome, but further investigation should be done for the best energy and duration to achieve the highest success rate. Surgical approach has the most predictable outcomes but with limited application due to its aggressiveness. Piezocision technique is considered one of the best surgical approaches because it poses good periodontal tissue response and excellent aesthetic outcome. Due to the advantages and disadvantages of each approach, further investigations should be done to determine the best method to accelerate tooth movement. PMID:24326040

Nimeri, Ghada; Kau, Chung H; Abou-Kheir, Nadia S; Corona, Rachel

2013-01-01

310

New generation of steel tooth bits improve drilling economics in western Canada  

Energy Technology Data Exchange (ETDEWEB)

The development of new tooth bit technologies which have provided cost effective solutions in mature, low cost, drilling applications was discussed. A new generation of steel tooth bits have recorded significant increases in meterage throughout western Canada. The new bits incorporate a unique gauge cutting structure, new tooth profile and improved hardfacing. Application of the new design in western Canada was reviewed providing specific examples of improved performance with the new tooth bit technologies. The overall experience has been that the new bits have resulted in important cost savings, and increases in durability have been achieved in all hole sizes with no sacrifice in penetration rate. 4 refs., 4 tabs., 18 figs.

Straub, D.; Scott, D.; Overstreet, J.

1997-04-01

311

Quality Control of Tooth Contact of Gear using Infrared Ray Imagery  

Science.gov (United States)

We propose a non-contact method using infrared ray thermography for measuring gear tooth contact to focus attention on the heat generated on the tooth surface at meshing. First, the radiation performance of the gear tooth surface and the effect of lubrication oil were investigated. Then, the reliability of this technique was evaluated by comparing with the observation result of tooth contact with red lead which is traditional red paint for industrial use. Finally, the possibility of evaluating the meshing transmission error was shown. The results show this technique is effective for monitoring the contact pattern and confirming the surface pressure.

Uenishi, Yasuhiro; Hirogaki, Toshiki; Aoyama, Eiichi; Iida, Takahiro; Nagata, Masaki

312

Tooth agenesis association with self-reported family history of cancer.  

Science.gov (United States)

It has been proposed that tooth agenesis and cancer development share common molecular pathways. We performed a cross-sectional study to investigate the epidemiological and molecular association between tooth agenesis and self-reported family history of cancer. Eighty-two individuals with tooth agenesis and 328 individuals with no birth defect were recruited from the same institution. Tooth agenesis was assessed in permanent teeth and was defined based on the age of the participants and when initial tooth formation should be radiographically visible. We also investigated the role of genes involved in dental development that have been implicated in tumorigenesis, and 14 markers in AXIN2, FGF3, FGF10, and FGFR2 were genotyped. Individuals with tooth agenesis had an increased risk of having a family history of cancer (p = 0.00006; OR = 2.7; 95% C.I., 1.6-4.4). There were associations between AXIN2, FGF3, FGF10, and FGFR2 with tooth agenesis [i.e., individuals who carried the polymorphic allele of FGFR2 (rs1219648) presented higher risk for having premolar agenesis (p = 0.02; OR = 1.8; 95% C.I., 1.1-3.0)]. In conclusion, tooth agenesis was associated with positive self-reported family history of cancer and with variants in AXIN2, FGF3, FGF10, and FGFR2. Prospective studies are needed to confirm if tooth agenesis can be used as a risk marker for cancer. PMID:23169889

Küchler, E C; Lips, A; Tannure, P N; Ho, B; Costa, M C; Granjeiro, J M; Vieira, A R

2013-02-01

313

Radioactive labeling in the study of abrasion of hard tooth tissue  

International Nuclear Information System (INIS)

Labeling the surface of hard tooth tissue samples by the nuclear recoil effect in radioactive decay was applied to study abrasion caused by abrasive components of tooth-pastes. 222Rn and its short-lived decay products were implanted into the surface in vacuum. For this purpose irradiation was applied to sample placed very close to thin 226Ra source. Measuring the activity before and after abrasion was used to evaluate abrasion in the system toothbrush - various suspensions of the tooth-pastes - hard tooth tissue (enamel or dentine) in a specially designed device, dentoabrasionmeter VUS 2. (author)

314

Molars extraction for bone graft study in rabbits Extração de molares para estudos de enxertos ósseos em coelhos  

OpenAIRE

PURPOSE: The aim of this study was to describe an experimental surgical technique to be used in the evaluation of bone grafts in rabbits. METHODS: The operative technique was performed in jaws, with external approach from the labial commissure to the last molar tooth. An incision about 1cm extended forward to the alveolar ridge, followed by a exposing the cervical region of the alveolar bone and dental elements was done. Thus, after extraction of first molar with forceps, the tooth socket lef...

José Eduardo Ferreira Manso; Carlos Fernando de Almeida Barros Mourão; Flávio Alexandre Lima Pinheiro; Manoel Luiz Ferreira; Paulo César Silva; Alberto Schanaider

2011-01-01

315

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)nd Pb in a fossil tooth. (author)

316

Modification of tooth size and shape in Down's syndrome.  

Science.gov (United States)

Individuals with Down's syndrome (DS) tend to display a reduction in size of permanent teeth, and reduced intercuspal distances in molars. A total of 51 permanent maxillary 1st molars of 26 DS children were examined from dental casts, 65 permanent maxillary 1st molars of normal children were examined from dental casts of 33 individuals. The following measurements were performed on both right and left molars (teeth 16 and 26 respectively): (1) all intercusp distance (distobuccal, db; distolingual, dl; mesiobuccal, mb; mesiolingual, ml); (2) the db-mb-ml, mb-db-ml, db-ml-mb, dl-mb-db, mb-dl-db, and dl-db-mb angles; (3) the area of the quadrangle shaped by connecting the cusp tips. All the intercusp distances were significantly smaller in the DS group. Stepwise logistic regression, applied to all the intercusp distances, was used to build a multivariate probability model for DS and normals. The mb-dl and mb-ml distances of the upper right molar (tooth 16) were sufficient to discriminate between DS and normal teeth: [table: see text] The probability for DS is higher when mb-ml is relatively higher in the mb-ml/mb-dl ratio. Another logistic analysis based on groups of angles revealed a combination of 3 angles which gave highly statistically significant discrimination between both groups: the mb-db-dl angle was higher in DS, the mb-dl-db angle was slightly smaller in DS, and the mb-ml-db angle was slightly smaller in DS. The dl cusp was located closer to the centre of the tooth. The change in size occurs at an early stage, while the change in shape occurs in a later stage of tooth formation in DS population. Our probability model for DS teeth is simple and practical because it requires only 2 intercusp distances to be put into the formula. PMID:8655403

Peretz, B; Shapira, J; Farbstein, H; Arieli, E; Smith, P

1996-02-01

317

Single-tooth replacement: factors affecting different prosthetic treatment modalities  

Directory of Open Access Journals (Sweden)

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

318

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

319

A study of tooth number anomaly using panoramic radiographs  

International Nuclear Information System (INIS)

The purpose of this study was to evaluate the prevalence and distribution of tooth number anomaly by means of the analysis of panoramic radiographs in 6,531 patients visited the Dental Infirmary of Kyungpook National University Hospital from January 1983 to May 1992 . The results were as follows : 1. The prevalence of congenitally missing teeth except third molar was revealed to be 10.8%, and there was a higher prevalence in females (44.6%) than in males (55.4%). Mandibular 2nd premolars (23.2%), and maxillary second primolars (15.4%) in descending order of frequency. As to the number of congentally missing teeth, the percentage of missing one tooth was 48%, missing two teeth was 35.4%, missing three teeth was 6.6%. 2. The prevalence of congenitally missing third molars was revealed to be 39.7%. There was a higher prevalence in the maxilla (60.3%) than in the mandible (39.7%). Maxillary right 3rd molars (30.6%) were absent most frequently, followed by maxillary left 3rd molar (29.7%), mandibular right 3rd molar (20.2%), mandibular left 3rd molar (19.5%) in descending order of frequency. 3. The prevalence of supernumerary teeth was revealed to be 4.2%, and there was a higher prevalence in the males (65.7%) than in females (34.3%). They were found most frequently in maxillary central incesor area (64.8%), followed by maxillary lateral incisor area (13.2%), posterior area of maxillary third molar (8.7%) in descending order of frequency. As to the number of supernumerary quency. As to the number of supernumerary teeth; the percentage of one supernumerary tooth was 79.9%, two supernumarary teeth was 8.9%, three supernumerary teeth was 1.2%.

320

The second international intercomparison on EPR tooth dosimetry  

International Nuclear Information System (INIS)

Eighteen international EPR laboratories participated in the second intercomparison programme. Each participant had to prepare enamel samples and evaluate the absorbed dose from molars that were irradiated in vitro in the range 0-1000 mGy. The objective of the programme was to bring together all methods which are currently applied by different laboratories for EPR dose reconstruction and to demonstrate the present state of dosimetry. An overview of the essential features of the different methods is presented. The current accuracy of EPR tooth enamel dosimetry under defined conditions of irradiation is evaluated

321

The second international intercomparison on EPR tooth dosimetry  

Energy Technology Data Exchange (ETDEWEB)

Eighteen international EPR laboratories participated in the second intercomparison programme. Each participant had to prepare enamel samples and evaluate the absorbed dose from molars that were irradiated in vitro in the range 0-1000 mGy. The objective of the programme was to bring together all methods which are currently applied by different laboratories for EPR dose reconstruction and to demonstrate the present state of dosimetry. An overview of the essential features of the different methods is presented. The current accuracy of EPR tooth enamel dosimetry under defined conditions of irradiation is evaluated.

Wieser, A. E-mail: wieser@gsf.de; Mehta, K.; Amira, S.; Aragno, D.; Bercea, S.; Brik, A.; Bugai, A.; Callens, F.; Chumak, V.; Ciesielski, B.; Debuyst, R.; Dubovsky, S.; Duliu, O.G.; Fattibene, P.; Haskell, E.H.; Hayes, R.B.; Ignatiev, E.A.; Ivannikov, A.; Kirillov, V.; Kleschenko, E.; Nakamura, N.; Nather, M.; Nowak, J.; Onori, S.; Pass, B.; Pivovarov, S.; Romanyukha, A.; Scherbina, O.; Shames, A.I.; Sholom, S.; Skvortsov, V.; Stepanenko, V.; Tikounov, D.D.; Toyoda, S

2000-12-15

322

Manufacture of Toothed Elements in Nanoausferritic Ductile Iron  

Directory of Open Access Journals (Sweden)

Full Text Available The technology currently used for the fabrication of toothed wheels, gear couplings and chain drums involves the induction hardening process or hardening and tempering after carburising. All these processes take a long time and cause adverse changes in the dimensions and surface quality of products, requiring post-treatment machining to remove the resulting cavities. The paper proposes the implementation of gear elements made of ductile iron with nanoausferritic matrix obtained by a new appropriate heat treatment process. The new material offers good performance characteristics and nearly no need for the application of other technological processes commonly used in the manufacture of gears.

Myszka D.

2014-10-01

323

Charcot-Marie-Tooth Disease: Seventeen Causative Genes  

OpenAIRE

Charcot-Marie-Tooth disease (CMT) is the most common form of inherited motor and sensory neuropathy. Moreover, CMT is a genetically heterogeneous disorder of the peripheral nervous system, with many genes identified as CMT-causative. CMT has two usual classifications: type 1, the demyelinating form (CMT1); and type 2, the axonal form (CMT2). In addition, patients are classified as CMTX if they have an X-linked inheritance pattern and CMT4 if the inheritance pattern is autosomal recessive. A l...

Lee, Jung-hwa; Choi, Byung-ok

2006-01-01

324

Endodontic Treatment of a Taurodontism Tooth: Report of a Case  

Science.gov (United States)

Taurodontism is a rare dental anomaly in which the involved tooth has an enlarged and elongated body and pulp chamber with apical displacement of the pulpal floor. Endodontic treatment of these teeth is challenging, because it is hard to identify the number of root canals. In this article a case of bilateral involvement of maxillary first molars is presented. Endodontic treatment of right maxillary first molar with taurodontism was indicated due to irreversible pulpitis. This article describes the procedures of root canal therapy. PMID:24454455

Nazari, Shahrzad; MirMotalebi, Farshid

2006-01-01

325

A family study of Charcot-Marie-Tooth disease.  

OpenAIRE

Forty-seven cases of Charcot-Marie-Tooth peripheral neuropathy were seen in 18 families within a defined area, with a disease prevalence of 1 in 16 400. Maximum motor nerve conduction velocity (MNCV) measurement divided off two types of neuropathy (MNCV less than 30 ms-1 and greater than 40 ms-1), but did not distinguish clinically affected from normal in families whose probands had median nerve MNCV greater than 40 ms-1. In the neuronal type of neuropathy ((MNCV greater than 40 ms-1) two gen...

Brooks, A. P.; Emery, A. E.

1982-01-01

326

Charcot-Marie-Tooth disease complicating type 2 diabetes.  

LENUS (Irish Health Repository)

Although both conditions are relatively common, there are very few descriptions of type 2 diabetes mellitus coexisting with Charcot-Marie-Tooth disease (CMT). This case report and literature review describes a 53-year-old Irish man who presented with type 2 diabetes and significant neuropathy, and who was subsequently diagnosed with CMT type 1A. This case report will also discuss how to differentiate diabetic neuropathy from a progressive hereditary neuropathy and how coexistence aggravates the progression of neuropathy thus necessitating early diagnosis.

Win, Htet Htet Ne

2012-02-01

327

Space-group determination of human tooth-enamel crystals  

International Nuclear Information System (INIS)

In the present work, we have determined the space group of human tooth-enamel crystals using - for the first time for a biological crystal - convergent beam electron diffraction (CBED). The symmetries observed in the different patterns we have obtained lead us to the P63/m hydroxyapatite space group. Disorder, most likely situated in the columns formed by the hydroxyl ions of the crystals, is suggested as a cause of weak intensity in the otherwise forbidden 000l (l odd) reflections and low visibility of first-order Laue zone (FOLZ) reflections in the CBED pattern from crystals oriented along the [0001] zone axis. A monoclinic phase was not observed. (orig.)

328

High-altitude illness induced by tooth root infection  

OpenAIRE

High-altitude illness may occur after recent pulmonary infection, but high-altitude illness after root canal therapy has not been described previously. A 44-year-old man is presented who skied to a 3333 m high peak in the Eastern Alps one day after he had undergone root canal therapy because of a tooth root infection. After 4 hours above 3000 m severe symptoms of high-altitude illness, including pulmonary oedema, developed. His condition improved after immediate descent. The next day he pr...

Finsterer, J.

1999-01-01

329

Bond durability between dentinal bonding agents and tooth structure.  

Science.gov (United States)

Glass-ionomer cements and dentinal bonding agents have made possible cavity preparations without mechanical retention. However, durability of bond strength is critical to the longevity of these restorations. This research evaluated the durability of the chemical bond formed by four materials attached directly to tooth structure. Tenure bonding agent recorded the strongest bond at each thermocycling time. In addition, whereas the bond strength remained unchanged for Scotchbond bonding agent, Ketac-Bond glass-ionomer cement, and GC lining cement, bond strength for Tenure bonding agent increased with thermocycling. PMID:2681691

Davis, E L; Joynt, R B; Wieczkowski, G; Laura, J C

1989-09-01

330

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 %

331

Monte Carlo dosimetric assessment in a 90Sr-Y contaminated tooth voxel model: feasibility study  

International Nuclear Information System (INIS)

Full text: In retrospective dosimetry studies, related to accidental and protracted exposure, a widely employed practice is the dose reconstruction in tooth enamel, based on the measurement by Electron Paramagnetic Resonance (EPR) of the paramagnetic centers induced by ionizing radiation in carbonate sites. This method is well established for exposure to external radiation, but it cannot discriminate the paramagnetic centers generated by sources incorporated in the tooth from those generated by exposure external to the tooth itself. Therefore, when radionuclides are incorporated in enamel and dentine, the internal enamel dose must be determined by an independent method. Since radiometric techniques are, in general, not enough sensitive for directly assessing the activity of the internal sources; an indirect approach based on dosimetric measurements using high sensitive Thermoluminescence Detectors (TLDs) can be employed to derive the radionuclide concentration in tooth, which needs then to be converted to dose in enamel. Such a conversion is operated through Monte Carlo electron transport calculation. To this purpose, simplified analytical models of tooth were originally developed by various authors. In those papers the tooth was modeled as a geometrical model (namely a cylinder). In this study a voxel model derived from microCT scans of a human molar tooth is presented (MOXEL). The energy deposition in the enamel was evaluated with MCNPX Monte Carlo code for a series of analytical tooth models and for MOXEL. The study is limited to the evaluation of the absorbed dose in tooth enamel only due to a 90Sr-Y radiation source uniformly distributed in the dentine of the tooth itself. The preliminary result demonstrated that the absorbed dose in the enamel is strongly dependent on the kind of tooth model adopted. (author)

332

Hedgehog signaling is required at multiple stages of zebrafish tooth development  

Directory of Open Access Journals (Sweden)

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

333

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

Directory of Open Access Journals (Sweden)

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

334

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

335

Tooth histology in the cretaceous ichthyosaur Platypterygius australis, and its significance for the conservation and divergence of mineralized tooth tissues in amniotes.  

Science.gov (United States)

Ichthyosaurs are an extinct group of secondarily aquatic reptiles that show ligamentous tooth attachment to the jaw in some derived forms. Here, we provide a modern description of tooth histology in ichthyosaurs, using Platypterygius australis, a large ichthyosaur from the Cretaceous of Australia. Our study supports evolutionary conservation of the principal mineralized tooth tissue types in amniotes with ligamentous tooth attachment: enamel, dentine, cellular, and acellular cementum. This is the first time that the latter tissue has been located in ichthyosaurs. Vascularized cementum (osteocementum) is reduced or absent in amniotes in which the teeth are ankylosed to the jaw bone, such as basal ichthyosaurs, and raises questions regarding the function of this tissue and the potential developmental or selective conditions leading to its convergent evolution. PMID:21210486

Maxwell, Erin E; Caldwell, Michael W; Lamoureux, Denis O

2011-02-01

336

Current concepts on the management of tooth wear: part 4. An overview of the restorative techniques and dental materials commonly applied for the management of tooth wear.  

Science.gov (United States)

This final article of the four part series on the current concepts of tooth wear will provide the reader with an evaluation of the data available in the contemporary literature with regards to the survival analysis of differing restorative materials, and their respective methods of application to treat tooth wear. It is vital that the dental operator is familiar with the role of differing materials which may be used to restore the worn dentition, some of which may prove to be more suitable for the management of particular patterns of tooth wear than others. The active management of tooth wear unfortunately commits the patient to a lifelong need for considerable maintenance, and it is imperative that this is understood from the outset. PMID:22361546

Mehta, S B; Banerji, S; Millar, B J; Suarez-Feito, J-M

2012-02-01

337

Evaluation of the effectiveness of the tooth whitening treatment associated with the immersion in coloring solutions  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Tooth whitening or dental bleaching is a cosmetic procedure that has established itself in Dentistry; however, the staining because of the ingestion of some types of food may cause several factors leading to the failure of this treatment. Objective: This study aimed to evaluate in vitro the influence of the immersion of whitened teeth in solutions with a high degree of pigmentation on the efficacy of the bleaching performed with 16% hydrogen peroxide. Material and methods: Fifty-six human teeth were selected, bleached for 4 hours a day during 14 days and randomly divided into 7 groups (n = 8. The groups G1/G2 and G3 were immersed in coloring solutions immediately (IM after bleaching (AP: G1 – tooth whitening + coffee (IM, G2 – tooth whitening + cola-based soft drink (IM and G3 – tooth whitening + red wine (IM; G4/and G6 were immersed in the solutions for 2 hours (AP, G4 – tooth whitening + coffee (AP, G5 – tooth whitening + cola based soft drink (AP, G6 – tooth whitening + red wine and (AP G7 – control. After bleaching with an immersion time of 5 minutes, with the aid of a digital spectrophotometer, the final color (FC was measured 24 hours after the end of the bleaching treatment (day 15. Results: The results for ANOVA showed no statistical differences in all groups. Conclusion: There was no influence on the effectiveness of tooth whitening immersed in coloring solutions.

Giovani de Oliveira Correa

2012-12-01

338

Quality-of-life in Charcot-Marie-Tooth disease: the patient's perspective.  

Science.gov (United States)

This study determines the impact of symptoms associated with Charcot-Marie-Tooth disease on quality-of-life. Charcot-Marie-Tooth patients in the Inherited Neuropathies Consortium Rare Diseases Clinical Research Network Contact Registry were surveyed. The survey inquired about 214 symptoms and 20 themes previously identified as important to Charcot-Marie-Tooth patients through patient interviews. Symptom population impact was calculated as the prevalence multiplied by the relative importance of each symptom identified. Prevalence and symptom impact were analyzed by age, symptom duration, gender, Charcot-Marie-Tooth type, and employment status. 407 participants returned the survey, identifying foot and ankle weakness (99.7%) and impaired balance (98.6%) as the most prevalent themes. Foot and ankle weakness and limitations with mobility were the themes with the highest impact. Both symptom prevalence and impact gradually increased with age and symptom duration. Several themes were more prevalent in women with Charcot-Marie-Tooth, including activity limitations, pain, fatigue, hip-thigh weakness, and gastrointestinal issues. All of the themes, except emotional or body image issues, were more prevalent among unemployed individuals. There were minimal differences in symptom prevalence between Charcot-Marie-Tooth types. There are multiple symptoms that impact Charcot-Marie-Tooth quality-of-life in adults. These symptoms have different levels of importance, are readily recognized by patients, and represent critical areas of Charcot-Marie-Tooth health. PMID:25092060

Johnson, Nicholas E; Heatwole, Chad R; Dilek, Nuran; Sowden, Janet; Kirk, Callyn A; Shereff, Denise; Shy, Michael E; Herrmann, David N

2014-11-01

339

Study on high-strength plastic teeth. Tooth discoloration.  

Science.gov (United States)

Conventional plastic teeth (CV teeth) are inferior to porcelain teeth in maintaining an adequate esthetic appearance with wear and discoloration, and thus have a shorter period of durability. Recently, high-strength plastic teeth (HS teeth) have been developed and applied to overcome the wear problems of CV teeth. Since HS teeth made of hard resin are still susceptible to staining with pigments, it has been observed that the esthetics of removable partial dentures made from such plastic teeth are gradually impaired in many patients. To investigate the susceptibility of HS teeth to pigments, we conducted an in vitro study by immersing three types of artificial teeth in three coloring liquids. It was found that the HS teeth tended to be less susceptible to the test pigments than the CV teeth to various degrees. In contrast, they showed markedly stronger susceptibility to the pigments than porcelain teeth. For all three artificial tooth types, daily tooth cleaning with an ultrasonic vibrator had a tendency to reduce the coloration in comparison with their counterparts without ultrasonic cleaning. PMID:8246042

Satoh, Y; Nagai, E; Azaki, M; Morikawa, M; Ohyama, T; Toyoma, H; Itoh, S; Sakurai, H; Iwasawa, A; Ohwa, M

1993-09-01

340

Assessment of performance parameters for EPR dosimetry with tooth enamel  

Energy Technology Data Exchange (ETDEWEB)

In the framework of a comparison between three laboratories, electron paramagnetic resonance (EPR) signal-to-dose response curves were measured for sets of 30 tooth enamel samples and the variance of EPR measurements in dependence on absorbed dose was evaluated, in nine combinations of laboratory of sample preparation and EPR evaluation, respectively. As a test for benchmarking of EPR evaluation, the parameters 'critical dose' and 'limit of detection' were proposed as performance parameters following definitions from chemical-metrology, and a model function was suggested for analytical formulation of the dependence of the variance of EPR measurement on absorbed dose. First estimates of limits of detection by weighted and unweighted fitting resulted in the range 101-552 and 67-561 mGy, respectively, and were generally larger with weighted than with unweighted fitting. Indication was found for the influence of methodology of sample preparation and applied EPR measurement parameters on performance of EPR dosimetry with tooth enamel.

Wieser, A. [Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Radiation Protection, Neuherberg (Germany)], E-mail: wieser@helmholtz-muenchen.de; Fattibene, P. [ISS-Istituto Superiore di Sanita, Department of Technology and Health, Rome (Italy); Shishkina, E.A. [URCRM-Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Ivanov, D.V. [IMP-Institute of Metal Physics, Russian Academy of Sciences, Ekaterinburg (Russian Federation); De Coste, V. [ISS-Istituto Superiore di Sanita, Department of Technology and Health, Rome (Italy); Guettler, A. [Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Radiation Protection, Neuherberg (Germany); Onori, S. [ISS-Istituto Superiore di Sanita, Department of Technology and Health, Rome (Italy)

2008-02-15

341

Diagnostic ultrasound tooth imaging using fractional Fourier transform.  

Science.gov (United States)

An ultrasound contact imaging method is proposed to measure the enamel thickness in the human tooth. A delay-line transducer with a working frequency of 15 MHz is chosen to achieve a minimum resolvable distance of 400 ?m in human enamel. To confirm the contact between the tooth and the transducer, a verification technique based on the phase shift upon reflection is used. Because of the high attenuation in human teeth, linear frequency-modulated chirp excitation and pulse compression are exploited to increase the penetration depth and improve the SNR. Preliminary measurements show that the enamel-dentin boundary creates numerous internal reflections, which cause the applied chirp signals to interfere arbitrarily. In this work, the fractional Fourier transform (FrFT) is employed for the first time in dental imaging to separate chirp signals overlapping in both time and frequency domains. The overlapped chirps are compressed using the FrFT and matched filter techniques. Micro-computed tomography is used for validation of the ultrasound measurements for both techniques. For a human molar, the thickness of the enamel layer is measured with an average error of 5.5% after compressing with the FrFT and 13.4% after compressing with the matched filter based on the average speed of sound in human teeth. PMID:21989873

Harput, Sevan; Evans, Tony; Bubb, Nigel; Freear, Steven

2011-10-01

342

Gear tooth stress measurements of two helicopter planetary stages  

Science.gov (United States)

Two versions of the planetary reduction stages from U.S. Army OH-58 helicopter main rotor transmissions were tested at NASA Lewis. One sequential and one nonsequential planetary were tested. Sun gear and ring gear teeth strains were measured, and stresses were calculated from the strains. The alternating stress at the fillet of both the loaded and unloaded sides of the teeth and at the root of the sun gear teeth are reported. Typical stress variations as the gear tooth moves through mesh are illustrated. At the tooth root location of the thin rimmed sun gear, a significant stress was produced by a phenomenon other than the passing of a planet gear. The load variation among the planets was studied. Each planet produced its own distinctive load distribution on the ring and sun gears. The load variation was less for a three planet, nonsequential design as compared to that of a four planet, sequential design. The reported results enhance the data base for gear stress levels and provide data for the validation of analytical methods.

Krantz, Timothy L.

1992-01-01

343

Ultrastructural organization and micromechanical properties of shark tooth enameloid.  

Science.gov (United States)

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

344

Tooth-derived stem cells: Update and perspectives  

Science.gov (United States)

Tissue engineering is an emerging field of science that focuses on creating suitable conditions for the regeneration of tissues. The basic components for tissue engineering involve an interactive triad of scaffolds, signaling molecules, and cells. In this context, stem cells (SCs) present the characteristics of self-renewal and differentiation capacity, which make them promising candidates for tissue engineering. Although they present some common markers, such as cluster of differentiation (CD)105, CD146 and STRO-1, SCs derived from various tissues have different patterns in relation to proliferation, clonogenicity, and differentiation abilities in vitro and in vivo. Tooth-derived tissues have been proposed as an accessible source to obtain SCs with limited morbidity, and various tooth-derived SCs (TDSCs) have been isolated and characterized, such as dental pulp SCs, SCs from human exfoliated deciduous teeth, periodontal ligament SCs, dental follicle progenitor cells, SCs from apical papilla, and periodontal ligament of deciduous teeth SCs. However, heterogeneity among these populations has been observed, and the best method to select the most appropriate TDSCs for regeneration approaches has not yet been established. The objective of this review is to outline the current knowledge concerning the various types of TDSCs, and discuss the perspectives for their use in regenerative approaches. PMID:25815123

Saito, Miki Taketomi; Silvério, Karina Gonzales; Casati, Márcio Zaffalon; Sallum, Enilson Antonio; Nociti Jr, Francisco Humberto

2015-01-01

345

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

346

Microfluidics co-culture systems for studying tooth innervation.  

Science.gov (United States)

Innervation plays a key role in the development and homeostasis of organs and tissues of the orofacial complex. Among these structures, teeth are peculiar organs as they are not innervated until later stages of development. Furthermore, the implication of neurons in tooth initiation, morphogenesis and differentiation is still controversial. Co-cultures constitute a valuable method to investigate and manipulate the interactions of nerve fibers with their target organs in a controlled and isolated environment. Conventional co-cultures between neurons and their target tissues have already been performed, but these cultures do not offer optimal conditions that are closely mimicking the in vivo situation. Indeed, specific cell populations require different culture media in order to preserve their physiological properties. In this study we evaluate the usefulness of a microfluidics system for co-culturing mouse trigeminal ganglia and developing teeth. This device allows the application of specific media for the appropriate development of both neuronal and dental tissues. The results show that mouse trigeminal ganglia and teeth survive for long culture periods in this microfluidics system, and that teeth maintain the attractive or repulsive effect on trigeminal neurites that has been observed in vivo. Neurites are repealed when co-cultured with embryonic tooth germs, while postnatal teeth exert an attractive effect to trigeminal ganglia-derived neurons. In conclusion, microfluidics system devices provide a valuable tool for studying the behavior of neurons during the development of orofacial tissues and organs, faithfully imitating the in vivo situation. PMID:25202282

Pagella, Pierfrancesco; Neto, Estrela; Jiménez-Rojo, Lucia; Lamghari, Meriem; Mitsiadis, Thimios A

2014-01-01

347

Evaluation of Reasons of Permanent Teeth Extraction in Iranian People (2009)  

OpenAIRE

Statement of Problem: Everyday, many people lose their teeth because of various reasons. Knowing the reasons of tooth extraction would help officials to make decisions for helping patients saving their teeth.Purpose: The aim of this study was to investigate the reasons of teeth extraction in dental clinics and some private offices in the city of Kerman in November 2009- February 2010.Materials and Method: In this cross-sectional study, the reasons of teeth extraction in 2076 teeth from 1500 p...

Kakoei S.; Fatemian M.; Eskandari Zadeh A.; Parirokh M.; Aa, Haghdoost

2012-01-01

348

Craniomandibular Trauma and Tooth Loss in Northern Dogs and Wolves: Implications for the Archaeological Study of Dog Husbandry and Domestication  

OpenAIRE

Archaeological dog remains from many areas clearly show that these animals suffered tooth fractures, tooth loss, trauma, and dental defects during their lives. Relatively little research has explored the meanings of these patterns, particularly for ancient dog remains from small-scale societies of the North. One limiting issue is the lack of comparative data on dental health and experiences of trauma among northern wolves and dogs. This paper examines tooth loss, tooth fracture, enamel hypopl...

Losey, Robert J.; Jessup, Erin; Nomokonova, Tatiana; Sablin, Mikhail

2014-01-01

349

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

350

Biofilms of black tooth stains: PCR analysis reveals presence of Streptococcus mutans.  

Science.gov (United States)

This study investigated the presence of the black-pigmented bacteria Prevotella nigrescens and Prevotella intermedia, the non-black-pigmented bacteria Actinomyces spp and particularly the cariogenic pathogen Streptococcus mutans in the dental biofilms of patients with or without black extrinsic tooth stains, using the multiplex polymerase chain reaction (PCR) technique. Analysis of the dental biofilms of patients with (n=26) or without (n=26) black tooth stains was performed using duplex PCR for the 16S ribosomal RNA gene (P. nigrescens, P. intermedia, Actinomyces spp) and glucosyltransferase-I gene for S. mutans. P. nigrescens and S. mutans were the most frequent bacteria detected in both groups. The least frequently detected were P. intermedia and Actinomyces spp. The similar bacterial composition of dental biofilms of black tooth stains and healthy tooth surfaces indicates that black tooth stains are not free of cariogenic bacteria. PMID:23306233

Costa, Marília Teixeira; Dorta, Miriam Leandro; Ribeiro-Dias, Fátima; Pimenta, Fabiana Cristina

2012-01-01

351

The use of surrogate variables to reflect long-term tooth survivability.  

Science.gov (United States)

Clinical parameters used to monitor periodontal patients are usually measures of the disease process. They are considered surrogate variables because changes in their status are interpreted to have an impact on the ultimate goal of periodontal therapy, which is tooth retention. However, their ability to reflect tooth survivability has been questioned because there is a lack of long-term data to validate that stable or improved surrogates result in reduced tooth loss. Therefore, to clarify the utility of employing surrogates to reflect long-term tooth retention, a number of issues related to their use are discussed in this commentary: phraseology, benefits and shortcomings, biologic credibility, and their previous successful utilization in monitoring the effects of therapy. This commentary supports the reasonableness of using surrogates to monitor periodontal status and suggests that a combination of surrogates that represent "periodontal clinical health" should be considered a true endpoint of periodontal therapy, since this outcome provides a condition conducive to tooth retention. PMID:16101375

Greenstein, Gary

2005-08-01

352

Visualization of Tooth for Non-Destructive Evaluation from CT Images  

International Nuclear Information System (INIS)

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.

353

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

354

Organ dose conversions from ESR measurements using tooth enamel of atomic bomb survivors  

International Nuclear Information System (INIS)

Dose conversions were studied for dosimetry of atomic bomb survivors based upon electron spin resonance (ESR) measurements of tooth enamel. Previously analysed data had clarified that the tooth enamel dose could be much larger than other organ doses from a low-energy photon exposure. The radiation doses to other organs or whole-body doses, however, are assumed to be near the tooth enamel dose for photon energies which are dominant in the leakage spectrum of the Hiroshima atomic bomb assumed in DS02. In addition, the thyroid can be a candidate for a surrogate organ in cases where the tooth enamel dose is not available in organ dosimetry. This paper also suggests the application of new Japanese voxel phantoms to derive tooth enamel doses by numerical analyses. (authors)

355

Retrospective dosimetry assessment using the 380 deg. C thermoluminescence peak of tooth enamel  

International Nuclear Information System (INIS)

The thermoluminescence (TL) response to gamma-ray irradiation of tooth enamel is reported. The tooth enamel was separated from dentine by using mechanical and physico-chemical procedures followed by grinding (grain size ?100 ?m) and etching. The TL was attributed to the recombination of CO2- radicals incorporated into or attached to the surface of hydroxyapatite crystals. The growth of the ?380 deg. C TL peak with absorbed dose was examined with irradiated tooth enamel samples and reconstructed doses evaluated for tooth enamel samples from four human subjects. - Highlights: ? Thermoluminescence response after gamma-ray irradiation of tooth enamel was investigated. ? Thermoluminescence was attributed to the recombination of CO2- radicals. ? CO2- radicals are produced inside or at the surface of hydroxyapatite crystals. ? From the growth of the 380C peak reconstructed doses have been evaluated.

356

Relationship between human tooth enamel free radical concentration and radiation dose  

International Nuclear Information System (INIS)

Free radical concentrations of 25 adult tooth enamel samples were measured by electron spin resonance (ESR) technique in this paper, and the relationship between free radical concentration of tooth enamel and radiation dose was also investigated. In the 25 adult enamel samples they are 16 male samples and 9 female samples, Ages of tooth donors range from 18-41 years. Difference in background ESR signal intensity between male and female samples was no observed; free radical concentration (or increment of radiation-induced free radical concentration) in tooth enamel increases linearly with increasing of radiation dose. In the case of radiation accident, the study results of this paper could be applied to dose estimation when conditions of ESR measurement of exposed individual tooth enamel are similar to measurement conditions of dose-effect calibration curve in this paper

357

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

Directory of Open Access Journals (Sweden)

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

358

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

Directory of Open Access Journals (Sweden)

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

359

Tooth fracture risk analysis based on a new finite element dental structure models using micro-CT data.  

Science.gov (United States)

The finite element (FE) analysis is an effective method to study the strength and predict the fracture risk of endodontically-treated teeth. This paper presents a rapid method developed to generate a comprehensive tooth FE model using data retrieved from micro-computed tomography (?CT). With this method, the inhomogeneity of material properties of teeth was included into the model without dividing the tooth model into different regions. The material properties of the tooth were assumed to be related to the mineral density. The fracture risk at different tooth portions was assessed for root canal treatments. The micro-CT images of a tooth were processed by a Matlab software programme and the CT numbers were retrieved. The tooth contours were obtained with thresholding segmentation using Amira. The inner and outer surfaces of the tooth were imported into Solidworks and a three-dimensional (3D) tooth model was constructed. An assembly of the tooth model with the periodontal ligament (PDL) layer and surrounding bone was imported into ABAQUS. The material properties of the tooth were calculated from the retrieved CT numbers via ABAQUS user's subroutines. Three root canal geometries (original and two enlargements) were investigated. The proposed method in this study can generate detailed 3D finite element models of a tooth with different root canal enlargements and filling materials, and would be very useful for the assessment of the fracture risk at different tooth portions after root canal treatments. PMID:22901677

Chen, G; Fan, W; Mishra, S; El-Atem, A; Schuetz, M A; Xiao, Y

2012-10-01

360

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)

361

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

Directory of Open Access Journals (Sweden)

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

362

Microleakage of endodontically treated teeth restored with prefabricated posts and tooth-colored restorative materials.  

Science.gov (United States)

This study evaluated the microleakage of endodontically treated teeth restored with prefabricated dowels and tooth-colored restoratives (Solitaire, Surefil, Filtek P60, Admira, Z-100) as core materials with and without the use of a flowable composite liner. A total of 200 extracted premolars were endodontically treated and prepared for post-core restorations. Prefabricated posts were inserted and cemented with resin cement into the root canals. Each resin system included the corresponding bonding agent for each respective flowable composite. For each group, half of the teeth were restored with composite alone, while the others were restored with the composite lined with flowable liner. Teeth were thermocycled for 1,000 cycles between 5 and 55 degrees C using a 30-second dwell time. The teeth were then coated with nail polish, placed in 5% methylene blue for 24 hours, sectioned, and scored for microleakage. Flowable liners reduced microleakage. Z-100 both with and without flowable liner demonstrated better resistance to leakage. Solitaire, Admira, and Filtek P60 showed more leakage than the other materials. PMID:15736780

Demirel, Figen; Saygili, Gülbin; Sahmali, Sevil

2005-02-01

363

Experimental Model for Retrospective Assessment of X-Ray Exposures in Dento-Maxillary Radiology Measured by Electron Paramagnetic Resonance in Tooth Enamel  

Directory of Open Access Journals (Sweden)

Full Text Available Electron paramagnetic resonance (EPR dosimetry of human tooth enamel has been widely used in measuring radiation doses in various scenarios. For experimental purposes in X-ray diagnostic or therapy human persons can not be involved. For such cases we have developed an EPR dosimetry technique making use of enamel of molars extracted from pigs. The method can evaluate doses and dose-profiles of irradiated teeth at low level as 50 – 100 mGy (in air. EPR-spectra acquisition, data processing and dose assessment were done using non-dedicated equipment, devices and software.

Ioana Costina DÂN?OREANU

2009-12-01

364

Experimental Model for Retrospective Assessment of X-Ray Exposures in Dento-Maxillary Radiology Measured by Electron Paramagnetic Resonance in Tooth Enamel  

OpenAIRE

Electron paramagnetic resonance (EPR) dosimetry of human tooth enamel has been widely used in measuring radiation doses in various scenarios. For experimental purposes in X-ray diagnostic or therapy human persons can not be involved. For such cases we have developed an EPR dosimetry technique making use of enamel of molars extracted from pigs. The method can evaluate doses and dose-profiles of irradiated teeth at low level as 50 – 100 mGy (in air). EPR-spectra acquisition, data processing a...

Da?ns?oreanu, Ioana Costina; Fildan, Floarea

2009-01-01

365

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

OpenAIRE

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 purpos...

Günay A; Of, Arpag?; Atilgan S; Yaman F; Atalay Y; Acikan I

2014-01-01

366

The influence of air polishers on tooth enamel. An in-vitro study.  

Science.gov (United States)

This study compares the effect of 4 different air-powder abrasive devices (PWS) (Air-Flow-S1, Clean-Jet, Prophy-Jet 30, Prophy-Unit) on tooth enamel. Freshly extracted bovine teeth were partially embedded in polyurethane, the labial surface ground flat and highly polished. Subsequently the teeth were subjected to the spray from the air-powder abrasive device for 60 s or polished with a prophylactic paste (CCS 170, CCS 250 or Cleanic) for the same length of time. The effects of the different air-powder abrasive systems were tested under multiple adjustments of powder/air and water. In addition the effects of air-powder abrasive systems and prophylactic pastes on several dentin surfaces were measured. The resulting surface textures of the teeth were examined using laser optic profilometry. In this process multiple measurements of roughness as well as tooth erosion were determined. The Clean-Jet led to significantly rougher surfaces than the 3 prophylactic pastes at every setting. The Air-Flow-S1, Prophy-Jet 30 and Prophy-Unit resulted in enamel abrasion that was either less than that caused by the prophylactic pastes or not significantly different at every examined setting. The 3 polishing pastes removed 3.6 microns to 7.2 microns of enamel in 60 s. The Clean-Jet removed significantly more enamel at every setting per unit of time than the prophylactic pastes (up to 0.1 mm/min); therefore routine application of this device is not advised. Enamel abrasion by the Air-Flow-S1, Prophy-Jet 30 and Prophy-Unit was either less than that measured with the prophylactic pastes or not significantly different. However, the Air-Flow-S1 was more abrasive than Cleanic paste at maximum water adjustment. The Air-Flow-S1 removed 641.2 microns/min of dentin compared to 339.6 microns/min by the Prophy-Jet 30. PMID:9505051

Jost-Brinkmann, P G

1998-01-01

367

Control of erosive tooth wear: possibilities and rationale  

Directory of Open Access Journals (Sweden)

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

368

Effect of microstructure upon elastic behaviour of human tooth enamel.  

Science.gov (United States)

Tooth enamel is the stiffest tissue in the human body with a well-organized microstructure. Developmental diseases, such as enamel hypomineralisation, have been reported to cause marked reduction in the elastic modulus of enamel and consequently impair dental function. We produce evidence, using site-specific transmission electron microscopy (TEM), of difference in microstructure between sound and hypomineralised enamel. Built upon that, we develop a mechanical model to explore the relationship of the elastic modulus of the mineral-protein composite structure of enamel with the thickness of protein layers and the direction of mechanical loading. We conclude that when subject to complex mechanical loading conditions, sound enamel exhibits consistently high stiffness, which is essential for dental function. A marked decrease in stiffness of hypomineralised enamel is caused primarily by an increase in the thickness of protein layers between apatite crystals and to a lesser extent by an increase in the effective crystal orientation angle. PMID:19345363

Xie, Z-H; Swain, M V; Swadener, G; Munroe, P; Hoffman, M

2009-05-29

369

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

370

Charcot-Marie-Tooth: are you testing for proteinuria?  

Science.gov (United States)

Charcot-Marie-Tooth disease (CMT) is a clinically and genetically heterogeneous group of inherited disorders affecting motor and sensory nerves of the peripheral nervous system. CMT has been reported to be associated with renal diseases, mostly focal segmental glomerulosclerosis (FSGS). However, it was unknown whether these two clinical manifestations represent one common underlying disorder or separate disease entities. Several reports have shown a high prevalence of mutations (75%) in the inverted formin gene (INF2) in patients with CMT-associated glomerulopathy, suggesting that these mutations are a common cause of the dual phenotype. For this reason, we strongly suggest to screen for proteinuria in CMT patients, in order to identify patients with this renal-neurologic phenotype in an early stage, and to perform genetic testing for INF2 mutations. PMID:25439738

De Rechter, Stéphanie; De Waele, Liesbeth; Levtchenko, Elena; Mekahli, Djalila

2015-01-01

371

Therapeutic options in Charcot-Marie-Tooth diseases.  

Science.gov (United States)

Charcot-Marie-Tooth (CMT) diseases represent a heterogeneous genetic disorder (more than 80 genes are implicated in these inherited neuropathies), but sharing a similar phenotype. In recent years, advances in molecular genetics and molecular biology, and also the development of various animal models of CMT, have led to a better understanding. Taken together, this knowledge represents a prerequisite for the development of future therapies in CMT, and in peripheral nervous system disorders in general. The efficacy of various substances has been shown in vitro and also in vivo (in animal models); but, no significant positive effect has yet been confirmed in humans. However, some of these trials are still in development, and we may expect positive results in the future. Although CMT is still an incurable disease, symptomatic treatments (physiotherapy, surgery, analgesic, etc.) are crucial to improve the quality of life of CMT patients. PMID:25703094

Mathis, Stéphane; Magy, Laurent; Vallat, Jean-Michel

2015-04-01

372

Spontaneous improvement of gingival recession after correction of tooth positioning.  

Science.gov (United States)

A 30-year-old woman sought treatment for malpositioned mandibular incisors; the roots were positioned outside the alveolar bone, related to severe localized gingival recession. She had been previously treated orthodontically and subsequently underwent 2 gingival grafts. The new treatment included torquing the roots back within the alveolar bone and referral to a periodontist for a gingival graft. In this clinical report, the possible spontaneous improvement of gingival recession is discussed. A hypothesis described in the literature is called the "creeping attachment" phenomenon. The literature includes conflicting reports about the cause-and-effect relationship between orthodontics and gingival recession. This clinical example reports spontaneous improvement of gingival recession after correction of tooth positioning in the alveolar bone. A gingival graft can be performed after adequate root positioning in the alveolar bone housing, thus increasing the chance of achieving more favorable results. PMID:24880854

Machado, Andre Wilson; MacGinnis, Matthew; Damis, Lucio; Moon, Won

2014-06-01

373

Update on the etiology of tooth resorption in domestic cats.  

Science.gov (United States)

Based on recent findings of increased vitamin D activity in cats with feline odontoclastic resorptive lesions (FORL), the present article provides further clues on the possible etiology of FORL. Microscopic features of FORL and other peculiarities of feline permanent teeth are compared with pathologic findings obtained from experimental studies in other species. Administration of excess vitamin D or vitamin D metabolites in laboratory animals caused changes to dental and periodontal tissues that resemble histopathologic features of teeth from cats with FORL. Chronic excess dietary vitamin D may be the long-sought cause of multiple tooth resorption in domestic cats. It may also provide a basis for future research on idiopathic hypercalcemia and renal disease in the same species. PMID:15979519

Reiter, Alexander M; Lewis, John R; Okuda, Ayako

2005-07-01

374

Space-group determination of human tooth-enamel crystals.  

Science.gov (United States)

In the present work, we have determined the space group of human tooth-enamel crystals using--for the first time for a biological crystal--convergent beam electron diffraction (CBED). The symmetries observed in the different patterns we have obtained lead us to the P6(3)/m hydroxyapatite space group. Disorder, most likely situated in the columns formed by the hydroxyl ions of the crystals, is suggested as a cause of weak intensity in the otherwise forbidden 000l (l odd) reflections and low visibility of first-order Laue zone (FOLZ) reflections in the CBED pattern from crystals oriented along the [0001] zone axis. A monoclinic phase was not observed. PMID:8442926

Brès, E F; Cherns, D; Vincent, R; Morniroli, J P

1993-02-01

375

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

376

Three-dimensional biofunctional adaptation in human tooth  

Science.gov (United States)

It is understood that once human tooth erupts into the oral cavity it models or adapts to the functional requirements imposed on it. In this study, experiments were conducted to evaluate the nature of dentine mineralization and mechanical property gradients using fluoroscopic X-ray imaging and instrumented micro-indentation techniques respectively. It was found that dentine adapts as a complex structure with significant gradients in its mineralization and elastic modulus. A significant relationship between the pattern of mineralization and the spatial gradients in mechanical properties was observed in the sagittal and cross-sections of the dentine. The natural gradation in the mechanical properties is explained by the two-dimensional and three- dimensional stress analysis conducted in anatomical scaled dento-osseous models using digital photoelasticity. This work highlights dentine structure as a biologically adapted Functionally Graded Material.

Kishen, Anil; Lim, Chu S.; Asundi, Anand K.

2001-10-01

377

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

378

Relationship of tooth wear to chronological age among indigenous Amazon populations.  

Science.gov (United States)

In indigenous populations, age can be estimated based on family structure and physical examination. However, the accuracy of such methods is questionable. The aim of this cross-sectional study was to evaluate occlusal tooth wear related to estimated age in the remote indigenous populations of the Xingu River, Amazon. Two hundred and twenty three semi-isolated indigenous subjects with permanent dentition from the Arara (n = 117), Xicrin-Kayapó (n = 60) and Assurini (n = 46) villages were examined. The control group consisted of 40 non-indigenous individuals living in an urban area in the Amazon basin (Belem). A modified tooth wear index was applied and then associated with chronological age by linear regression analysis. A strong association was found between tooth wear and chronological age in the indigenous populations (p <0.001). Tooth wear measurements were able to explain 86% of the variation in the ages of the Arara sample, 70% of the Xicrin-Kaiapó sample and 65% of the Assurini sample. In the urban control sample, only 12% of ages could be determined by tooth wear. These findings suggest that tooth wear is a poor estimator of chronological age in the urban population; however, it has a strong association with age for the more remote indigenous populations. Consequently, these findings suggest that a simple tooth wear evaluation method, as described and applied in this study, can be used to provide a straightforward and efficient means to assist in age determination of newly contacted indigenous groups. PMID:25602501

Vieira, Elma Pinto; Barbosa, Mayara Silva; Quintão, Cátia Cardoso Abdo; Normando, David

2015-01-01

379

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

380

Imaging of human tooth using ultrasound based chirp-coded nonlinear time reversal acoustics.  

Science.gov (United States)

Human tooth imaging sonography is investigated experimentally with an acousto-optic noncoupling set-up based on the chirp-coded nonlinear time reversal acoustic concept. The complexity of the tooth internal structure (enamel-dentine interface, cracks between internal tubules) is analyzed by adapting the nonlinear elastic wave spectroscopy (NEWS) with the objective of the tomography of damage. Optimization of excitations using intrinsic symmetries, such as time reversal (TR) invariance, reciprocity, correlation properties are then proposed and implemented experimentally. The proposed medical application of this TR-NEWS approach is implemented on a third molar human tooth and constitutes an alternative of noncoupling echodentography techniques. A 10 MHz bandwidth ultrasonic instrumentation has been developed including a laser vibrometer and a 20 MHz contact piezoelectric transducer. The calibrated chirp-coded TR-NEWS imaging of the tooth is obtained using symmetrized excitations, pre- and post-signal processing, and the highly sensitive 14 bit resolution TR-NEWS instrumentation previously calibrated. Nonlinear signature coming from the symmetry properties is observed experimentally in the tooth using this bi-modal TR-NEWS imaging after and before the focusing induced by the time-compression process. The TR-NEWS polar B-scan of the tooth is described and suggested as a potential application for modern echodentography. It constitutes the basis of the self-consistent harmonic imaging sonography for monitoring cracks propagation in the dentine, responsible of human tooth structural health. PMID:21371732

Dos Santos, Serge; Prevorovsky, Zdenek

2011-08-01

381

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

Energy Technology Data Exchange (ETDEWEB)

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

382

Parathyroid Hormone: Is It Really the Cause for Increased Tooth Mobility after Orthognathic Surgery?  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Following orthognathic surgery, increased tooth mobility is observed clinically and is utilized for postsurgical orthodontic tooth movement. It was suggested that the increase may result from a surgery-associated alteration of parathyroid hormone (PTH and calcium metabolism. Materials and Methods: 30 young adult patients were divided into a mandibular osteotomy group (Group A, n = 20 and an untreated control group (Group B, n = 10. Tooth mobility was evaluated using the Periotest device. Tooth mobility, serum PTH and calcium levels were determined repeatedly for both groups. Results: The tooth mobility was increased significantly in the Group A patients in the first 10 days post-surgery. All serum PTH and calcium mean levels were within normal ranges. No significant differences were found between the measurements of both groups. The serum calcium levels recorded at the 1st post-surgery day were slightly lower in the operated patients compared to the control group. Conclusion: It can be concluded that the increased facility of orthodontic tooth movement immediately post-surgery was confirmed by Periotest measurements, while no association was found with surgery-related altered levels of PTH and calcium. Since dietary effects can be ruled out, the increase of clinical tooth mobility may rather result from preoperative orthodontic forces and/or the post-surgical elimination of masticatory muscular influences.

Nezar Watted

2014-08-01

383

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

Directory of Open Access Journals (Sweden)

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

384

Relationship between free radical content in child tooth enamel and radiation dose  

International Nuclear Information System (INIS)

Free radical contents of the tooth enamel in 25 children permanent tooth and 35 milk tooth samples were measured by electron spin resonance (ESR) technique, and the relationship between free radical content of the tooth enamel and radiation dose was also investigated. Of the 25 children tooth samples there are 13 male samples and 12 female samples respectively, 20 male samples and 15 female samples. In 35 milk tooth samples permanent and milk tooth samples were divided into 5 dose groups each, and irradiated with 60Co ? ray at dose rate of 0.48 Gy/min. Radiation doses of 5 groups were 0.30, 0.50, 1.00, 3.00 and 5.00 Gy, respectively. Results indicated that there was no significant difference in background ESR signal intensity between male and female samples for both children permanent teeth and milk teeth. And also no significant difference in background ESR signal intensity between children permanent teeth and milk teeth was observed. Free radical content of teeth enamel increased linearly with increasing of radiation dose. The results could be applied to dose estimation of exposed individual in the case of radiation accident. Two methods of ESR dosimetry were also discussed

385

Relationship of Tooth Wear to Chronological Age among Indigenous Amazon Populations  

Science.gov (United States)

In indigenous populations, age can be estimated based on family structure and physical examination. However, the accuracy of such methods is questionable. The aim of this cross-sectional study was to evaluate occlusal tooth wear related to estimated age in the remote indigenous populations of the Xingu River, Amazon. Two hundred and twenty three semi-isolated indigenous subjects with permanent dentition from the Arara (n = 117), Xicrin-Kayapó (n = 60) and Assurini (n = 46) villages were examined. The control group consisted of 40 non-indigenous individuals living in an urban area in the Amazon basin (Belem). A modified tooth wear index was applied and then associated with chronological age by linear regression analysis. A strong association was found between tooth wear and chronological age in the indigenous populations (p <0.001). Tooth wear measurements were able to explain 86% of the variation in the ages of the Arara sample, 70% of the Xicrin-Kaiapó sample and 65% of the Assurini sample. In the urban control sample, only 12% of ages could be determined by tooth wear. These findings suggest that tooth wear is a poor estimator of chronological age in the urban population; however, it has a strong association with age for the more remote indigenous populations. Consequently, these findings suggest that a simple tooth wear evaluation method, as described and applied in this study, can be used to provide a straightforward and efficient means to assist in age determination of newly contacted indigenous groups. PMID:25602501

Vieira, Elma Pinto; Barbosa, Mayara Silva; Quintão, Cátia Cardoso Abdo; Normando, David

2015-01-01

386

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.

387

Magnesium stable isotope ecology using mammal tooth enamel.  

Science.gov (United States)

Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (?(13)C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (?(44)Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (?(26)Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for ?(26)Mg, ?(13)C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that ?(26)Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this (26)Mg enrichment up the trophic chain is due to a (26)Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using ?(26)Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel ?(26)Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages. PMID:25535375

Martin, Jeremy E; Vance, Derek; Balter, Vincent

2015-01-13

388

Proteins, pathogens, and failure at the composite-tooth interface.  

Science.gov (United States)

In the United States, composites accounted for nearly 70% of the 173.2 million composite and amalgam restorations placed in 2006 (Kingman et al., 2012), and it is likely that the use of composite will continue to increase as dentists phase out dental amalgam. This trend is not, however, without consequences. The failure rate of composite restorations is double that of amalgam (Ferracane, 2013). Composite restorations accumulate more biofilm, experience more secondary decay, and require more frequent replacement. In vivo biodegradation of the adhesive bond at the composite-tooth interface is a major contributor to the cascade of events leading to restoration failure. Binding by proteins, particularly gp340, from the salivary pellicle leads to biofilm attachment, which accelerates degradation of the interfacial bond and demineralization of the tooth by recruiting the pioneer bacterium Streptococcus mutans to the surface. Bacterial production of lactic acid lowers the pH of the oral microenvironment, erodes hydroxyapatite in enamel and dentin, and promotes hydrolysis of the adhesive. Secreted esterases further hydrolyze the adhesive polymer, exposing the soft underlying collagenous dentinal matrix and allowing further infiltration by the pathogenic biofilm. Manifold approaches are being pursued to increase the longevity of composite dental restorations based on the major contributing factors responsible for degradation. The key material and biological components and the interactions involved in the destructive processes, including recent advances in understanding the structural and molecular basis of biofilm recruitment, are described in this review. Innovative strategies to mitigate these pathogenic effects and slow deterioration are discussed. PMID:25190266

Spencer, P; Ye, Q; Misra, A; Goncalves, S E P; Laurence, J S

2014-12-01

389

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

Scientific Electronic Library Online (English)

Full Text Available 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

390

Functional implications of variation in tooth spacing and crown size in Pinnipedimorpha (Mammalia: Carnivora).  

Science.gov (United States)

Pinnipeds (seals, sea lions, and walruses) show variation in tooth morphology that relates to ecology. However, crown size and spacing are two aspects of morphology that have not been quantified in prior studies. We measured these characters for nearly all extant pinnipeds and three fossil taxa and then determined the principal sources of variation in tooth size and spacing using principal components (PCA) and hierarchical cluster analysis (HCA). PCA and HCA showed that species sorted into three groups: taxa with small crowns and large diastemata, taxa with large crowns and small diastemata, and taxa that fell between these two extremes. We then performed discriminant function analysis (DFA) to determine if tooth morphology correlated with foraging strategy or diet. DFA results indicated weak correlation with diet, and stronger correlation with prey capture strategies. Tooth size and spacing were most strongly correlated with the importance of teeth in prey acquisition, with tooth size decreasing and tooth spacing increasing as teeth become less necessary in capturing food items. Taxa which relied on teeth for filtering prey from the water column or processing larger or tougher food items generally had larger crowns and smaller tooth spacing then taxa which swallowed prey whole. We found the fossil taxa Desmatophoca and Enaliarctos were most similar in tooth morphology to extant otariids, suggesting that both taxa were generalist feeders. This study established the relationship between tooth size and feeding behavior, and provides a new tool to explore the paleoecology of fossil pinnipeds and other aquatic tetrapods. Anat Rec, 2014. © 2014 Wiley Periodicals, Inc. PMID:25367223

Churchill, Morgan; Clementz, Mark T

2014-11-01

391

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

392

Tooth Erosion and Eating Disorders: A Systematic Review and Meta-Analysis  

Science.gov (United States)

Background Eating disorders are associated with the highest rates of morbidity and mortality of any mental disorders among adolescents. The failure to recognize their early signs can compromise a patient's recovery and long-term prognosis. Tooth erosion has been reported as an oral manifestation that might help in the early detection of eating disorders. Objectives The aim of this systematic review and meta-analysis was to search for scientific evidence regarding the following clinical question: Do eating disorders increase the risk of tooth erosion? Methods An electronic search addressing eating disorders and tooth erosion was conducted in eight databases. Two independent reviewers selected studies, abstracted information and assessed its quality. Data were abstracted for meta-analysis comparing tooth erosion in control patients (without eating disorders) vs. patients with eating disorders; and patients with eating disorder risk behavior vs. patients without such risk behavior. Combined odds ratios (ORs) and a 95% confidence interval (CI) were obtained. Results Twenty-three papers were included in the qualitative synthesis and assessed by a modified version of the Newcastle-Ottawa Scale. Fourteen papers were included in the meta-analysis. Patients with eating disorders had more risk of tooth erosion (OR?=?12.4, 95%CI?=?4.1–37.5). Patients with eating disorders who self-induced vomiting had more risk of tooth erosion than those patients who did not self-induce vomiting (OR?=?19.6, 95%CI?=?5.6–68.8). Patients with risk behavior of eating disorder had more risk of tooth erosion than patients without such risk behavior (Summary OR?=?11.6, 95%CI?=?3.2–41.7). Conclusion The scientific evidence suggests a causal relationship between tooth erosion and eating disorders and purging practices. Nevertheless, there is a lack of scientific evidence to fulfill the basic criteria of causation between the risk behavior for eating disorders and tooth erosion. PMID:25379668

Hermont, Ana Paula; Oliveira, Patrícia A. D.; Martins, Carolina C.; Paiva, Saul M.; Pordeus, Isabela A.; Auad, Sheyla M.

2014-01-01

393

Bleaching of a non-vital anterior tooth to remove the intrinsic discoloration.  

Science.gov (United States)

Intrinsic discoloration of a non-vital permanent incisor tooth due to trauma may have a significant esthetic and social impact on children and adolescents. Treatment options for discolored Non-vital teeth are bleaching, crowns or veneers. However, this restorative crown or veneer approach has a significant drawback of being an invasive technique. Intervention should be minimal destruction of tooth structure and should not compromise future restorative options. The advantage bleaching over crown is that it offers simple conservative approach in removal of stain and whitening discolored teeth without damaging tooth structure. PMID:25097441

Patil, Anandkumar G; Hiremath, Vinaykumar; Kumar, R Sheetal; Sheetal, Aparna; Nagaral, Suresh

2014-07-01

394

Analysis of EPR tooth enamel spectra exposed to combined radiation and mechanical effects  

Energy Technology Data Exchange (ETDEWEB)

In the EPR spectra of tooth enamel samples exposed to sequential radiation and mechanical effect, the intensity of the signal in the spectra of tooth enamel samples exposed to sequential mechanical and radiation effects exceeded the amplitude of a signal in enamel samples that were only exposed to radiation. The increased dosimetric signal can be explained by superposition of mechanically and radiation-induced signals. The contribution of the mechanically induced component to the individual dose load reconstructed by EPR-spectra of tooth enamel has been evaluated.

Kirillov, V. [Laboratory for EPR Dosimetry and Cytology, Belarusian State Medical University, 23 Philimonova Street, 220114 Minsk (Belarus)], E-mail: kirillov@bsmu.by; Shimanskaya, O.; Tolstik, S. [Laboratory for EPR Dosimetry and Cytology, Belarusian State Medical University, 23 Philimonova Street, 220114 Minsk (Belarus)

2007-07-15

395

Retrospective EPR dosimetry on the basis of tooth enamel analyses of Techa river area residents  

International Nuclear Information System (INIS)

The dose in tooth enamel from residents of villages along the Techa river was measured by EPR dosimetry. The results were correlated to the 90Sr whole body burden as measured about 30 years after ingestion. Based on the results of this preliminary investigation the ingestion dose coefficient of tooth enamel for 90Sr is estimated and compared with the value for bone surface given in ICRP. The results of the preliminary study suppose a similar metabolism of strontium for tooth dentine and the skeleton. (author)

396

Tooth replacement of tigerfish Hydrocynus vittatus from the Kruger National Park  

OpenAIRE

Evidence of tooth replacement was observed in 14 tigerfish which had been caught during the period 1991 - 1993 in the Olifants and Letaba rivers in the Kruger National Park. Replacement of teeth is a quick process (3-5 days) and first replacement of adult coni- cal dentition takes place at six to seven months post hatch, at a body length of 100 mm (FL). Swollen gums are evident prior to tooth replacement and newly erupted teeth are loosely embedded in the gums. Tooth replacement occurs i...

Gagiano, C. L.; Steyn, G. J.; Du Preez, H. H.

1996-01-01

397

Tooth replacement of tigerfish Hydrocynus vittatus from the Kruger National Park  

OpenAIRE

Evidence of tooth replacement was observed in 14 tigerfish which had been caught during the period 1991 - 1993 in the Olifants and Letaba rivers in the Kruger National Park. Replacement of teeth is a quick process (3-5 days) and first replacement of adult coni- cal dentition takes place at six to seven months post hatch, at a body length of 100 mm (FL). Swollen gums are evident prior to tooth replacement and newly erupted teeth are loosely embedded in the gums. Tooth replacement occurs in bot...

Gagiano, C. L.; Steyn, G. J.; Du Preez, H. H.

1996-01-01

398

Staged orthodontic movement of mesiolinguoversion of the mandibular canine tooth in a dog.  

Science.gov (United States)

A 10 mo old Sapsaree dog presented for evaluation and treatment of malocclusion causing palatal trauma. A class III malocclusion with mesiolinguoversion of the 404 and enamel hypoplasia was diagnosed based on oral examination. It was decided to attempt orthodontic correction of the mesiolinguoverted tooth using an elastic chain and inclined bite plane technique with crown restoration of the enamel hypoplasia teeth. One year after the orthodontic correction and composite removal, the mesiolinguoverted right mandibular canine tooth was moved to an acceptable location within the dental arch and the locally discolored right maxillary canine tooth was vital. PMID:25415215

Kim, Chun-Geun; Lee, So-Young; Park, Hee-Myung

2015-01-01

399

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

OpenAIRE

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

400

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

401

Deconvolution of complex EPR spectrum of tooth enamel into three components: native, dosimetric and mechanical  

International Nuclear Information System (INIS)

A software was developed on the base of non-linear simulation, which allowed the deconvolution of EPR spectra of tooth enamel into three components: native, radiation- and mechanically induced. The software was designed for the reconstruction of individual absorbed doses by EPR spectra of tooth enamel using the method of additive irradiation of samples. It has been demonstrated with the help of this program that the presence of mechanically induced paramagnetic centers in enamel samples led to an excessive individual absorbed dose reconstructed by EPR spectra of tooth enamel.

402

Analysis of EPR tooth enamel spectra exposed to combined radiation and mechanical effects  

International Nuclear Information System (INIS)

In the EPR spectra of tooth enamel samples exposed to sequential radiation and mechanical effect, the intensity of the signal in the spectra of tooth enamel samples exposed to sequential mechanical and radiation effects exceeded the amplitude of a signal in enamel samples that were only exposed to radiation. The increased dosimetric signal can be explained by superposition of mechanically and radiation-induced signals. The contribution of the mechanically induced component to the individual dose load reconstructed by EPR-spectra of tooth enamel has been evaluated

403

Comparative evaluation of four transport media for maintaining cell viability in transportation of an avulsed tooth – An in vitro study  

Science.gov (United States)

Objectives: The study was performed to compare and evaluate the efficacy of four experimental storage media (Hank's balanced salt solution, Ringer's lactate solution, tender coconut water, and green tea extract) for maintaining cell viability of human periodontal cells at different time intervals of 15 min 30 min, 60 min, and 90 min. Materials and Methods: Human periodontal cells were cultured and stored in the four media. After 15 min 30 min, 60 min, and 90 min, the different media were examined under optical microscope and viabilities analyzed using an optical calorimeter. Mean and standard deviation were estimated from the results that were statistically analyzed using one-way analysis of variance (ANOVA) to identify the significant groups. Results: The results indicated that there was no difference in cell viability between the four media up to a period of 60 min, whereas green tea extract showed a lower cell viability after 90 min. Conclusion: Within the limitations of the present study, it appears that due to superior osmolality, cost effectiveness, and easier availability, Ringer's lactate, tender coconut water, and green tea extract can be used as alternate storage media for avulsed tooth.

Bharath, Makonahalli Jaganath; Sahadev, Chickmagravalli Krishnegowda; Ramachandra, Praveen Kumar Makonahalli; Rudranaik, Sandeep; George, Jijo; Thomas, Ashna

2015-01-01

404

Evaluation of the Effect of Green Tea Extract on the Prevention of Gingival Bleeding after Posterior Mandibular Teeth Extraction: A Randomized Controlled Trial  

Science.gov (United States)

Background. Removing tooth results in gingival bleeding. Several measures are taken to stop bleeding. In this study, the effect of green tea extract on cessation of bleeding and oozing after removing of mandibular molars was investigated. Methods. This was a randomized controlled clinical trial carried out on 62 patients who were referred for extraction of their mandibular molars. The volunteers were randomly and equally divided into treatment and control groups. In the first group, green tea extract-impregnated sterile gauze was used after removing the tooth while in the second group, green tea extract-free gauze was applied. Active bleeding and oozing monitoring was done every 5 minutes until cessation of bleeding and one hour after that, respectively. The results were compared using t-test. Results. The mean?±?SD of bleeding duration in green tea group was significantly lower than control group (5.87 ± 1.76 versus 10.09 ± 3.61 minutes, P = 0.001). In addition, the number of people with oozing one hour after surgery was significantly lower in the green tea group (6 versus 29 persons, P = 0.001). Conclusion. This study showed that green tea extract contributes to significant decline in bleeding of the socket caused by tooth extraction as well as reduction of oozing. PMID:25024733

Haghighat, Abbas; Fanaei, Mehrdad; Asghari, Gholamreza

2014-01-01

405

Identification of a tooth-like foreign body in swine sausage.  

Science.gov (United States)

A tooth-like foreign body (FB) was found inside a sausage bread. Analysis aimed to investigate whether the FB was a tooth and its origin. The FB was measured, weighed, photographed, and radiographed. Macroscopic findings were suggestive of an anterior tooth. Histological slides of undecalcified cross-sections of the FB and samples of human and swine teeth were prepared. Histological features of the FB (in light microscopy, 125× magnification) were discrepant from human tissues. Compared histological analysis displayed majority of features consistent with a hypsodont swine tooth, probably a canine. Cellularized cementum in crown region, adjacent to the enamel, and shape of the cementocytes were the main criteria excluding the possibility of human origin of the FB. Scanning electronic microscopy and energy-dispersive spectroscopy were not performed because of fewer features to be analyzed and FB size. It was concluded that the FB may have been incorporated during meat grinding of the sausage. PMID:22804486

Dias, Paulo Eduardo Miamoto; Beaini, Thiago Leite; Melani, Rodolfo Francisco Haltenhoff

2012-09-01

406

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

407

Comparison of three non-destructive methods to measure 90Sr in human tooth samples  

International Nuclear Information System (INIS)

Between 1949 and 1951 about 100 PBq of intermediate and low level liquid radioactive wastes were released into the Techa River (Southern Urals, Russia). To estimate the radiation exposure of Techa River residents having taken place in the past, EPR measurements of tooth enamel were performed. The cumulative dose obtained by EPR, however, is due to both, external photons and internal 90Sr incorporated in enamel and dentin. To provide estimates of the 90Sr content in the teeth tissue, three supplementary methods are used: • visualization and mapping of the 90Sr distribution in tooth tissue using Imaging Plates. • measurements of the 90Sr activity in tooth tissue samples using a ?-spectrometer. • measurements of dose rate due to 90Sr in tooth samples using thin-layer Al2O3:C TL dosimeters.

408

Comparison of the effects of four different power scalers on enamel tooth surface in the dog.  

Science.gov (United States)

The surface roughness of tooth enamel was quantitatively evaluated following scaling with four power scalers at three different tip forces. Ceramic and tooth samples were evaluated for surface roughness using surface profilometry. Applied tip forces were produced with a horizontal balanced arm holding the scaler handpiece and load weight, and were measured using a load cell. The power scalers evaluated were the ultrasonic piezoelectric, ultrasonic magnetostrictive (ferromagnetic stack), sonic, and rotosonic. For the tooth samples, at 50 grams of force, the piezoelectric, magnetostrictive, and sonic scaler roughnesses were similar and the rotosonic scaler outcome was statistically higher. Increasing the applied force significantly increased the roughness produced by the rotosonic and piezoelectric scalers. The results of this study indicate that the type of power scaler and applied tip force used determines the post-scaling surface roughness of ceramic and tooth enamel surfaces. PMID:11968928

Brine, E J; Marretta, S M; Pijanowski, G J; Siegel, A M

2000-03-01

409

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

410

An abelisaurid (Dinosauria: Theropoda) tooth from the Lower Cretaceous Chicla formation of Libya  

Science.gov (United States)

An isolated theropod dinosaur tooth discovered in 1984 near Nalut in northwestern Libya is the only known dinosaur record from the Aptian-Albian (Lower Cretaceous) Chicla Formation in the Jabal Nafusah region of the country. The tooth was re-examined in an effort to better ascertain its taxonomic affinities. A stepwise discriminant function analysis compared the Libyan tooth to the dentitions of 24 other theropods and classified the tooth with cranial material from the Late Cretaceous of India previously referred to the abelisaurid Indosuchus. The temporal and paleogeographic "distance" separating the Libyan specimen from " Indosuchus" indicates that the former cannot pertain to that genus. However, the results of the analysis and synapomorphies of Abelisauridae present on the Libyan crown indicate that it can be referred to the clade, thus contributing to the growing record of Abelisauridae in the Cretaceous of mainland Africa.

Smith, Joshua B.; Dalla Vecchia, Fabio M.

2006-10-01

411

Tooth Decay Process: How to Reverse It and Avoid a Cavity  

Science.gov (United States)

... such as calcium and phosphate) plus fluoride from toothpaste, water, and other sources. This team helps enamel ... by using minerals from saliva, and fluoride from toothpaste or other sources. But if the tooth decay ...

412

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

Directory of Open Access Journals (Sweden)

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

413

Relationship between microhardness and fluorine contents on tooth enamel determined by PIGE analysis  

International Nuclear Information System (INIS)

The remineralization effect of fluoride has been measured by surface microhardness on tooth enamel. The purpose of this study was to investigate the relationship between microhardness and fluorine concentration on tooth enamel. Twelve sound bovine enamel specimens were prepared and immersed in 0.05% NaF solution for 1, 3, 6, 24 and 36 hours, respectively. The concentration of fluorine in specimens were measured by PIGE analysis and surface microhardness of each specimen was measured by surface microhardness tester. Fluorine concentration was increased by immersing time. There was no change in microhardness of each specimen by fluorine content. The results of this study suggest that there was no relationship between the fluorine concentration and surface microhardness in sound tooth enamel. PIGE analysis can be used effectively to assess the remineralization effect of fluorine content in tooth enamel. (author)

414

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

Directory of Open Access Journals (Sweden)

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

415

Professional and patient-based evaluation of oral rehabilitation in patients with tooth agenesis  

DEFF Research Database (Denmark)

OBJECTIVES: The outcome of oral rehabilitation is usually monitored with clinical tests rather than by patient's perception of change. The aim of this study was to describe the objective measure and subjective perception of oral rehabilitation in patients with tooth agenesis. MATERIAL AND METHODS: The study included 129 patients with tooth agenesis rehabilitated with implant- or tooth-supported reconstructions, and a control group of 58 patients. Professional assessments included biological, technical and aesthetic variables. An aesthetic index score included mucosal discoloration, crown morphology, crown color match, occlusal harmony, and papilla level. The Oral Health Impact Profile (OHIP) questionnaire was used to evaluate the patient-based outcomes. Six OHIP questions were subtracted to evaluate the patient-based aesthetic outcomes. RESULTS: Severe root resorption was observed in 36% of the patients in whom orthodontic treatment had been performed. Twelve percent of patients had implants with 5-7 mm peri-implant bone defects. Mucosal discoloration was recorded in 57% of the patients. Twelve percent of the patients had metal visible on the buccal side. The median scores for all five aesthetic variables were acceptable in 92% of the implant reconstructions and for 83% of the tooth-supported fixed dental prostheses (FDPs). The total OHIP score was inferior in rehabilitated patients with tooth agenesis to that of the control group without tooth agenesis. The total OHIP score after rehabilitation was <50 for 95% of the patients with tooth agenesis. The six OHIP questions concerning aesthetics demonstrated patient-based aesthetic problems in 41% of patients treated with implant-supported reconstructions and 47% of patients treated with tooth-supported FDPs. Ninety-eight percent of the group treated with implant-supported reconstructions and 84% of the patients in the tooth-supported FDP group were very satisfied or satisfied with the treatment outcome. CONCLUSIONS: Patients with tooth agenesis had a high risk ofsevere root resorption after orthodontic treatment. A better aesthetic outcome was obtained with implant-supported reconstructions than with tooth-supported reconstructions. A positive but not significant correlation was observed between the professional and patient-based evaluations of aesthetic outcomes.

Dueled, Erik; Gotfredsen, Klaus

2009-01-01

416

Development of In Vivo Tooth EPR for Individual Radiation Dose Estimation and Screening  

OpenAIRE

The development of in vivo EPR has made it feasible to perform tooth dosimetry measurements in situ, greatly expanding the potential for using this approach for immediate screening after radiation exposures. The ability of in vivo tooth dosimetry to provide estimates of absorbed dose has been established through a series of experiments using unirradiated volunteers with specifically irradiated molar teeth placed in situ within gaps in their dentition and in natural canine teeth of patients wh...

Williams, Benjamin B.; Dong, Ruhong; Kmiec, Maciej; Burke, Greg; Demidenko, Eugene; Gladstone, David; Nicolalde, Roberto J.; Sucheta, Artur; Lesniewski, Piotr; Swartz, Harold M.

2010-01-01

417

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.

2011-12-01

418

Biochemical characterization of human gingival crevicular fluid during orthodontic tooth movement using Raman spectroscopy  

OpenAIRE

This study used Raman spectroscopy to report the first human gingival crevicular fluid (GCF) biochemical characterization during the early phase of orthodontic tooth movement. This technique allows for label-free and noninvasive biochemical change monitoring in GCF during orthodontic tooth movement. Ten orthodontic patients (20.8 ± 2.5 years) participated in the study. GCF samples were obtained before (baseline, 0 days) and during orthodontic treatment at 1, 7 and 28 days. For Raman spectros...

Jung, Gyeong Bok; Kim, Kyung-a; Han, Ihn; Park, Young-guk; Park, Hun-kuk

2014-01-01

419

Witkop?s tooth and nail syndrome: A multifaceted approach to dental management  

OpenAIRE

Witkop?s tooth and nail syndrome is a rare autosomal dominant disorder of ectodermal dysplasia characterized by hypodontia and nail dysplasia. Mutations in MSX-1 have been shown to be associated with this syndrome. There is failure of development and eruption of the dentition. Tooth shape may vary; the most common forms are conical and narrow crowns. The nails may be spoon shaped and slow growing and affect both finger and toe nails. The nail involvement is more severe in childhood. Th...

Subramaniam P; Neeraja R

2008-01-01

420

Triclosan-loaded Tooth-binding Micelles for Prevention and Treatment of Dental Biofilm  

OpenAIRE

The purpose of the present study was to develop tooth-binding micelle formulations and evaluate their ability to both inhibit initial biofilm formation as well as decrease the viability of preformed biofilm using an in vitro dental biofilm model. Alendronate (ALN, a bisphosphonate) was covalently attached to the ends of different Pluronic copolymers to confer tooth-binding ability to the micelles, and triclosan was used as a model drug. Based on different micelle preparation methods, Pluronic...

Chen, Fu; Rice, Kelly C.; Liu, Xin-ming; Reinhardt, Richard A.; Bayles, Kenneth W.; Wang, Dong

2010-01-01