Proximal contact tightness of class â ¡ bulk-fill composite resin restorations: An in vitro study.

This study investigated the effect of bulk-fill composites on proximal contact tightness (PCT) of composite restorations using different matrix systems. 150/standardized-MO-ivorine cavity preparations were divided into 5 groups; Smart Dentin Replacement (SDR), SonicFill (SF), Tetric EvoCeram Bulk-Fill (TEB), G-ænial Universal Flo (GF) and Tetric EvoCeram (TE). Each group was subdivided into 3 sub-groups (n=10); Dixieland band in Tofflemire retainer, FenderMate and Palodent plus matrix systems. PCT was measured 24 h post-curing using Tooth Pressure Meter. PCT means were calculated and statistically-analyzed using ANOVA and Tukey's post-hoc test (p<0.05). Means and SD of PCT for Tofflemire subgroup were: 1.75(0.13), 3.21(0.1), 3.06(0.19), 2.49(0.21) and 3.18(0.1) for (SDR), (SF), (TEB), (GF) and (TE), respectively. Using FenderMate, values were: 1.87(0.08), 3.35(0.12), 3.17(0.16), 2.64(0.1) and 3.26(0.11) for (SDR), (SF), (TEB), (GF) and (TE), respectively, while with Palodentplus; 3.16(0.17), 4.23(0.11), 4.1(0.1), 3.46(0.17) and 3.98(0.1) for (SDR), (SF), (TEB), (GF) and (TE), respectively. ANOVA revealed significant differences (p<0.05) between all samples except between (SF), (TEB) and (TE) and also significant difference between Palodentplus and two subgroups. Effect of bulk-fill composites on PCT is material dependent. Separation ring is recommended for proper PCT.

Bonding System Choice and Practices among Senior Dental Students.

AIM AND OBJECTIVE: This survey investigated bonding system type and composite application rationale by senior dental students at a dental school in Saudi Arabia. MATERIALS AND METHODS: Eighty-three questionnaires with 15 open and closed questions were randomly distributed to final year dental students about the use of etch and rinse versus self-etch adhesives and application techniques for posterior resin composite. Data were collected, and statistical analysis was done using Chi-square test (0.05) with two factors "question answer" and "gender." RESULTS: For all questions, the impact of gender was statistically nonsignificant (P > 0.05). Etch and rinse adhesive was significantly (P > 0.05) favored by students with majority do not perform selective etching, use intermittent air for drying tooth structure, apply a single layer bonding agent and thin it by air, cure it for 20 s with the curing tip at close proximity to the cavity, use incremental application technique for composite restorations, cure it for 40 s, and neglect to do extra curing. CONCLUSION: Students showed good knowledge regarding the bonding and composite application steps but with some clear mispractices such as low frequency of selective etching, less etchant washing, and the preference of vertical layering. Moreover, results from the current investigation should direct curricular updates in the future.

Relative hardness of composite buildups polymerized with two different LED lights.

The relative hardness (RH) of five composite materials was determined through polymerization via LED lights. Disk specimens were prepared by using composites composed of Artiste, an experimental glass fiber composite, Filtek Supreme, Z100, and LuxaCore. Specimens were polymerized for 10 and 20 seconds from the top surface only with two lights, Smartlite-IQ2 and DEMI LED, with light maintained 8 mm from the surface through a coronal section of the molar tooth. Knoop hardness numbers were determined for the top and bottom surfaces both immediately and 24 hours later. Ten RH values per group were calculated and data were statistically analyzed. Generally, RH increased with increasing polymerization time. The DEMI LED light resulted in RH values that were significantly higher than those obtained with Smartlite IQ2. Z100 had RH values of > 80% under most testing conditions and had the highest hardness values of all composites tested. Therefore, it is considered to be the most appropriate for core buildups.