Effect of resin-based material combination on the compressive and the flexural strength.

The mechanical properties, elasticity and compressive strength, of restorative materials play a crucial role during mastication for clinical performance of materials in particular stress bearing areas at posterior regions. This in vitro study was objected to evaluate the changes in the compressive and flexural strength of tooth-coloured resin-based dental restorations placed on flowable composites. Specimens in the control group were produced in cylindrical form for testing compressive strength and in quadrangular prism form for flexural strength test. Tetric Ceram, Charisma, Surefil, Admira and two compomers; Dyract AP and Compoglass F in test group specimens were fabricated by placing the control materials on different flowables. The material combinations were as follows: Tetric Ceram/Tetric Flow Charisma/Flowline, Surefil/Dyract Flow, Admira/Admira Flow, Dyract AP/Dyract Flow, Compoglass F/Compoglass Flow. Compressive strength values were measured at the Instron Testing Machine with a cross-head speed of 10 mm min(-1) while flexural strength were determined in three-point bending with a cross-head speed of 1 mm min(-1). One-way anova and Tukey's multiple comparison tests were performed for the statistical analysis. The flexural strength values of Tetric Ceram/Tetric Flow (135.9 +/- 3.2), Charisma/Flowline (120.4 +/- 5.6) and Compoglass F/Compoglass Flow (108.2 +/- 5.2) combinations were statistically greater than Tetric Ceram (110.8 +/- 10.5), Charisma (95.3 +/- 5.3) and Compoglass F (86.9 +/- 4.9). The results of the present study support the idea that the placement of flowable composite as a liner under the resin-based composite restoratives increase the flexural strength.

A comparative study of two fissure sealants: a 2-year clinical follow-up.

The aim of the study was to compare the fluoride-containing fissure sealants (Helioseal F) with the conventional (Concise Light Cure White Sealant) fissure sealants in their retention and caries-prevention capabilities in young population. Sealant materials were applied by three dentists on 122 fissures of first and second molars in 59 adults, 18-20 years of age. One hundred and twenty-two non-carious and unsealed molar teeth were selected as controls. The teeth were assessed using the following criteria: 1 - fully retained (FR), 2 - partially lost (PL), 3 - totally lost (TL) and 4 - decayed (D). All teeth were clinically assessed at 3, 6, 12 and 24 months by two examiners who were blinded to the sealant materials. Data were statistically analysed with chi-square tests. After 3 months 72.1% of sealants were fully retained, at 24 months this had dropped to 46.7%. The partial loss of sealants was at 3 months (15.6%), 6 months (26.2%), 12 months (27.9%) and 24 months (27%). The total loss of Helioseal F (16.4, 19.7, 18, 23% at 3rd, 6th, 12th and 24th months, respectively) was more than the total loss of Concise Light Cure White Sealant (8.2, 9.8, 11.5, 18%, respectively); meaning that the retention rate of Helioseal F was lower than for Concise Light Cure White Sealant. No caries was detected at 3rd and 6th months in all sealant-treated teeth. The incidence of caries in Helioseal F treated teeth at 12 and 24 months was 11.5% and 0% in Concise Light Cure White Sealant treated teeth. The incidence of caries in all fissure-sealant-treated-teeth after 24 months was 5.7 and 25.4% in control group. The results underline that the application of fissure sealants to young people in this sample is an effective method for the prevention of fissure caries.

Alstrom syndrome: a case report.

Alstrom syndrome is a rare disorder characterized by early obesity, loss of central vision, diabetes mellitus, hearing loss and short stature. Previous studies, have reported no information regarding oral findings. This article describes oral findings in two cases of Alstrom syndrome. In both cases, gingivitis was present and also light yellow-brown discolored enamel bands were observed on the anterior teeth. This staining may have resulted from discoloration of the preexisting slight band-like enamel hypoplasia. The gingiva was examined histologically by light and transmission electron microscopy. Irregular thickness of the basal lamina and delamination of the myelin sheath were detected by transmission electron microscopy. There is no information about pathological odontogenesis in Alstrom syndrome in previous reports. Oral present findings may contribute further information about the clinical manifestations of Alstrom syndrome.