Brazilian gutta-percha points. Part II: thermal properties

This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also sought to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130 degrees. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130 degrees C causes changes to its chemical structure which permanently alter its physical properties.     

Multilevel assessment of determinants of dental caries experience in Brazil

OBJECTIVE: To examine contextual and individual determinants of dental caries experience, documenting levels of the disease in Brazil. METHODS: The dental status of 34 550 12-year-old schoolchildren was informed by a country-wide survey of oral health comprising 250 towns and performed in 2002-2003. Indices assessing dental caries experience were compared by sociodemographic characteristics of examined children (gender, ethnic group, localization and type of school), and geographic characteristics of participating towns [the human development index (HDI), and access to fluoridated tap water]. A multilevel model fitted the adjustment of untreated caries to individual and contextual covariates. RESULTS: Better-off Brazilian regions presented an improved profile of dental health, besides having a less unequal distribution of restorative dental treatments between blacks and whites, rural and urban areas, and public and private schools. Girls [odds ratio (OR)=1.1; 95% confidence interval (CI): 1.0-1.1], blacks (OR=1.6; 95% CI: 1.5-1.7), and children studying in rural areas (OR=1.9; 95% CI: 1.7-2.0) and public schools (OR=1.7; 95% CI: 1.6-1.9) presented higher odds of having untreated decayed teeth. The multilevel model identified the fluoride status of tap water (beta=-0.3), the proportion of households linked to the water network (beta=-0.3), and the HDI (beta=-0.2), as town-level variables associated with caries levels. CONCLUSION: Dental caries experience is prone to sociodemographic and geographic inequalities. The monitoring of contrasts in dental health outcomes is relevant for programming socially appropriate interventions aimed both at overall improvements and at the targeting of resources for groups of population presenting higher levels of needs.     

Multiple hyperdontia: Report of an unusual case

Supernumerary teeth are an infrequent developmental anomaly that can appear in any area of the dental arch and can affect any dental organ. Multiple supernumerary teeth, or hyperdontia, is rare in people with no other associated diseases or syndromes. Conditions commonly associated with hyperdontia include cleft lip and palate, trichorhinophalangeal syndrome, cleidocranial dysplasia, and Gardner's syndrome. A black girl, aged 11 years 8 months, came for consultation; radiographs showed 81 teeth: 18 deciduous, 32 permanent, and 31 supernumerary. The main concern initially was to determine whether she was syndromic, and she was referred to a geneticist. G banding analysis showed pericentric inversion of chromosome 9; the chromosome formula was 46, XX, inv (9) (p13q21). Orthodontic treatment for this patient will be a clinical challenge because of the great number of teeth to be extracted and the alterations in the shapes of the teeth. Treatment goals should be established by a multidisciplinary team, where oral surgeon, orthodontist, periodontist, and prosthodontist come together to solve a medical and dental puzzle, eliminating the pieces that do not fit and searching for new ones to obtain an occlusion that will give the patient physiologic conditions of normality and esthetic satisfaction.     

Early implant failure. Prognostic capacity of Periotest: retrospective study of a large sample

Objectives: The objectives of this study were to determine the accuracy of Periotest^® to monitor primary implant stability at first‐stage surgery, to identify by multivariate analysis the variables associated with early implant failure and to compare Periotest^® with radiographic study in the diagnosis of implant stability at second‐stage surgery (during osseointegration period). Material and methods: A 10‐year retrospective study was conducted on 1084 Brånemark^® implants placed in 316 patients. Clinical variables, implant diameter and length, Periotest^® values (PTVs) and radiological variables were analyzed in bivariate and multivariate studies in order to determine their influence on early implant failure. Results: After examination of the sensitivity and specificity values obtained for different PTV cutoff points, a cutoff PTV of ?2 was selected (84% sensitivity and 39% specificity). In the bivariate analysis, early failure was significantly related to smoking habits, implant location, bone type, implant features and PTVs (?2 and ≥?2). In the final multiple logistic model, only age (odds ratio (OR)=4.53; 95% confidence interval (CI), 1.34–15.27), smoking habits (OR=2.5; 95% CI, 1.3–4.79), bone type (OR=1.93; 95% CI, 1.01–3.7) and PTV at first surgery (OR=3.01; 95% CI, 1.5–6.02) were independently related to early failure. Conclusions: The Periotest^® (with ?2 cutoff) at first surgery offers high sensitivity in the prognosis of early implant loss and shows a greater capacity to evaluate stability during the osseointegration period compared with radiographic study.     

Influence of resin composite shade and location of the gingival margin on the microleakage of posterior restorations

OBJECTIVE: The objective of this in vitro study was to evaluate the influence of resin composite shade and location of the gingival margin (enamel or dentin) on the microleakage of proximal restorations on posterior teeth. Methods and MATERIALS: Sixty freshly extracted human third molars were prepared with standardized Class II box-shaped cavities with proportional size and shape, with distal gingival margins located on the enamel and mesial gingival margins on dentin. The teeth were randomly divided into 6 groups according to resin shade (n=10): G1-Incisal; G2-A1; G3-A2; G4-A3; G5-A3.5; G6-A4. The cavities were restored with a total-etch 1-bottle adhesive system and microhybrid resin composites inserted in 4 increments, light cured for 20 seconds through the occlusal surface, then an additional 60 seconds for each surface. After 1 week of immersion in distilled water, the specimens were thermocycled (500 cycles, 5 degrees -55 degrees C, 30 seconds dwell time), sealed with nail polish and immersed in 0.5% basic fuschin solution for 24 hours. The restorations were sectioned longitudinally, and microleakage was evaluated using a 0-3 score scale. RESULTS: Data were subjected to Kruskal-Wallis and Wilcoxon tests at p<0.05. No statistically significant differences between groups were observed regarding the shade of resin composite (p=0.8570). When margins (enamel or dentin) were considered separately, statistically significant differences were observed between groups (p<0.0001), with enamel margins exhibiting lower degrees of microleakage. CONCLUSION: The variation of resin composite shades utilized in this study did not influence the microleakage of Class II restorations. However, the location of the gingival margin influenced the microleakage.     

Oral myiasis: a case report

Oral Myiasis is a rare pathology in humans and is associated with poor oral hygiene, alcoholism, senility, suppurating lesions, severe halitosis and others conditions. The treatment is a mechanical removal of the maggots one by one but a systemic treatment with Ivermectin, a semi-synthetic macrolide antibiotic, have been used for treatment for oral myiasis. We present a case report of a 32-year-old man indigent, alcohol-dependent with an extensive necrotic area and acute swelling in upper lip and fetid odor. The patient's management included topic use of gentian violet, oral therapy with ivermectin (6 mg orally), surgical exploration to remove the larvae and necrotic tissue. After the complete larvae removal the swelling and the wounds were healing normally, the patients was referred to plastic surgery to repair tissue damage. The prevention of human myiasis is by education, but unfortunately in the developing countries some people live in low social condition, predisposing the occurrence of the infestation.