Efeito cariostático de restaurações adesivas em superfícies radiculares: estudo in vitro

Dental materials that release fluoride have been shown to be effective in caries inhibition around restorations. Adhesive materials would also be effective in caries inhibition by sealing and protecting cavity margins from acidic demineralization. This in vitro study tested the hypothesis that composite restorations with a dentin adhesive system have a caries preventive effect similar to that of an adhesive material with fluoride - glass-ionomer cement - on root surfaces. Twenty roots from extracted sound third molars were embedded in polystyrene resin and ground flat. Standardized cavities were prepared in leveled root surfaces and randomly restored with (a) Chelon-Fil (Espe) or (b) Z100/SingleBond (3M). Baseline indentations were measured at 100, 200 and 300 mum from the occlusal margins of each restoration and the surface microhardness values were obtained using a Knoop diamond indenter. A 2.0 mm wide margin around the restorations was submitted to a pH-cycling model, at 37ºC. After that, surface microhardness was measured again, as it was before. The differences between baseline and final surface microhardness were considered for statistical analysis. The median values of differences were (a): -3.8; -0.3; -1.0; and (b): 3.3; 2.5; 1.7, for the distances of 100, 200 and 300 mum, respectively. The Kruskal-Wallis test did not show statistically significant difference between 100, 200 and 300 mum distances in each tested group. There was no difference between the studied materials at the distances of 200 and 300 mum. Chelon-Fil was statistically different from Z100/SingleBond, at 100 mum (p<0.05). Under the studied conditions, the glass-ionomer cement had a higher caries preventive effect than the composite/dentin adhesive restorations.

Avaliação in vitro do aparelho DIAGNOdent para diagnóstico oclusal

The aim of this study was to determine the effectiveness and reliability of laser fluorescence measurements in relation to occlusal caries diagnosis. DIAGNOdent 2095 (Kavo, Biberach, Germany), which has been developed especially for caries diagnosis, was utilized. Five (5) teeth were examined in the pilot test; after that, ten (10) teeth were examined in order to calibrate both examiners. Data were obtained from 66 teeth (36 molars and 30 premolars), totalizing 144 sites identified through photographs of the occlusal surfaces. Reproducibility was evaluated in 10 teeth. The interexaminer Spearman correlation (r) was 0.89 and the intra-examiner, 0.93 and 0.97 (examiner A and B, respectively). Validation was carried out by histological examination (stereomicroscope). For the two examiners the sensitivity of the device was relatively high, varying from 0.81 to 1.00, while specificity varied according to which validation criterion was used (0.77 - 0.86: enamel lesion / 0.52 - 0.59: dentin lesion). It was concluded that DIAGNodent presented good capacity of identifying any alteration of the dental surface, nevertheless it presents the disadvantage of accomplishing many false-positive diagnosis when the validation criterion is dentin lesion.