Fadiga de grampos de retenção em prótese parcial removível. Efeito de ligas, espessuras e técnicas de fusão. Parte I.

The authors looked for the verification of the fatigue of retentive clasps utilized on the removable partial denture. According to this, it was idealized and built on assay machine, that through movements, simulate the insertion and removal of the clasp for a pattern tooth, manufactured on cobalt-chromium which has all the preparation normally utilized to the correct confection of this type of prosthesis. It was utilized three different commercial alloys based on cobalt-chromium: L1-Biosil; L2-Steldent; L3-Duracron. It was utilized the T clasp of Roach, with was tested upon three different proportions among width and thickness: E1-1.7;E2-2.0 and E3-2.3 and was casted through two casting techniques: F1-oxygen-gas and F2-oxygen-acetylene. The clasps were tested on the machine, which allowed the reading of the number of insertion and removal cycles made until fatigue appeared. The obtained results were submitted to the statistic analysis and the authors concluded that: a) L3 (Duracrom) obtained the best results followed by L1 (Biosil) and finally L3 (Steldent); b) among the analyzed thickness, the best results were obtained by E3, followed by E2 and after this E1; c) form the casting techniques, F2 gave us the best results.

Fadiga de grampos de retenção em prótese parcial removível. Efeito de ligas, espessuras e técnicas de fusão. Parte II.

The authors tested the T clasp of Roach in three differents proportions among width and thickness: E1-1.7; E2-2.0 and E3-2.3, with a constant length of 15 mm. These clasps were casted with three cobalt-chromium alloys (L1-Biosil; L2-Steldent and L3-Duracrom), through two casting techniques (F1-oxygen-gas and F2-oxygen-acetylene). The fatigue of the clasps were verified by using and assay machine, that through movements, simulate the insertion and removal of the clasps for a pattern which were obtained from a premolar, prepared in a surveyor. This machine detect the fatigue of the clasps and count the number of cycles of insertion and removal realized. The obtained results of the interaction between the analysed factors, were submitted to the statistic analysis and the authors concluded that: a) the interaction of factors, Alloy x Thickness, Alloy x Casting Technique and Thickness x Casting Technique did not change the order of effects that the factors showed separately but gave rise to effects of different magnitude for any observed sense; b) the simultaneous interaction of the factors Alloy x Thickness x Casting Technique confirmed the superiority of the L3 alloy, the thickness E3 and the F2 casting technique.

Prevalência de anodontia entre estudantes do 2O grau da cidade de São José dos Campos-Correlação dessa anomalia entre terceiros molares e outros órgão dentários.

The authors studied 201 school children form both sexes, aging 12 to 14 years, in order to identify anodontia, including in third molars. The results indicated a congenital absence of teeth in 24.37% of the examined children, distributed into 10.44% of boys and 13.93% of girls. Anodontia was observed concerning third molar teeth and other teeth, and the correlation was calculated by the total, sex, and hemiarch. The data were presented and discussed, and the results included several conclusions.

Freqüência de raízes fusionadas, separadas divergentes, separadas convergentes, separadas retilíneas e dilaceradas dos terceiros molares.

In a sample of Brazilian white young adults between 18-23 years old, the A.A. studied the third molar roots, in anatomical aspects, using the orthopantomographic radiographic method. They concluded that the superior third molar shows a biggest number of fusionated roots (19.50% in the right side and 19.66% in the left side) and the inferior third molar shows a biggest number of separated roots (21.48% in the right side and 19.66% in the left side).

O programa de saúde bucal para crianças pré-escolares em Araraquara-SP-O desempenho em 1988.

This paper reports the composition change of the dmf-teeth index, outcome from dental health program for the 3 to 6 year old pre-school children population, enrolled in kindergartens in Araraquara-SP, in 1988. The program performance promotes a major contribution of the f component to the dmf-teeth index.

Efeitos da estimulação ultra-sônica sobre o processo de reparo em ferida de extração dental: estudo histológico em ratos.

The effects of ultrasound on the wound healing process after teeth extractions were studied histologically. The right upper incisor was extracted in 56 rats. They were divided into 2 groups, one control (I) and one experimental (II). Group II received ultrasound stimulation that was applied with the frequency of repetition of 1,000 Hz and pulse length of 2,000 us continuously, during five minutes daily since the extraction day until 24 hours before the death. The rats were sacrificed at 3, 6, 9, 12, 15, 18, and 21 postoperative days. The results showed a precocious granulation tissue formation, faster remodeling of osseous ridges, and consequently acceleration of the alveolar wound healing process.

Dimensión vertical de la región anterior de la mandíbula

We made some measurements from the region of the symphysis menti in 308 dried mandibles; 247 belong to the collection of the cranial museum of the discipline of Anatomy of the UNIFESP- Escola Paulista de Medicina- EPM and 61 belong to the didactic laboratory of the discipline of Anatomy from the Faculdade de Odontologia de Araraquara- UNESP, Brasil. On the dentate mandibles, the highest value founded was of 43,46 mm and the lowest of 22,67 mm. On the edentate mandibles, the highest value founded was of 37,24 mm and the lowest of 6,22mm. We hope that with the following discoveries we could contribute to a better knowledge of the symphysis menti region, not only to the professionals in Surgery and Implantology areas, but the industrials of related areas, to the confection of instruments used in these practices. © 2007 Sociedad Chilena de Anatom•br>.

Potencial tóxico dos alginatos para uso odontológico

Alginate or irreversible hydrocolloid is one the most accepted and frequently employed impression materials in dental practice. Substances like zinc, cadmium, lead silicate and fluorides, which are included in several alginate brands with the aim of improving their physical, chemical and mechanical properties, are a source of serious concern as regards their toxicity. Some brands of alginate have been reported to contain potentially toxic fluorides and metals such as cadmium, lead and zinc silicates, either singly or combined. Consequently, special care should be taken while preparing of these materials. It is necessary to monitor potentially toxic chemicals and metals in the alginates continually to avoid contamination of dental professionals and patients. In this review, alginates used in dentistry are analyzed for potential toxicity.

Influência dos agentes clareadores na microdureza de resina composta nanoparticulada

Objective: To assess the effect of bleaching agents on the microhardness of nanoparticle resin composite. Methods: Twenty-eight cylindrical test specimens (8× 1mm) of Filtek™ Supreme XT resin (3M/ESPE) were prepared and divided into 5 groups. The initial Vickers microhardness was measured (load of 50 grams force for 30 seconds) on the top surface of the test specimens. The groups were treated and divided as follows: G1 - artificial saliva (21 days - control); G2 - 7% hydrogen peroxide gel applied for 4h/day, for 14 days; G3 - 10% carbamide peroxide for 4h/day, for 14 days: G4 - 35% hydrogen peroxide gel applied in three sessions of 30 minutes each, with an interval of one week (21 days) between the sessions; G5 - 35% carbamide peroxide, three sessions of 30 minutes each, with an interval of one week (21 days) between the sessions. The top surfaces of the test specimens received treatment and were submitted to the Vickers microhardness test. Results: The results obtained were submitted to the Analysis of Variance at a fixed criterion, at a level of significance of p=0.05. No significant differences were observed among the treatments tested (p=0.42) when compared with G1. Significant differences (Tukey test) were found when the initial microhardness values were compared with the values after experimental treatments (p<0.01). Conclusion: The application of bleaching agents did not alter the microhardness of resin composites. Therefore, there is no need to change restorations after bleaching.