Raphael Vieira Monte Alto

Amalgam and resin composite longevity of posterior restorations: A systematic review and meta-analysis

OBJECTIVES The aim of the present review was to evaluate by means of a systematic review and meta-analysis the hypothesis of no difference in failure rates between amalgam and composite resin posterior restorations. DATA Randomized controlled trials, controlled clinical trials and prospective and retrospective cohort studies were included in this review. The eligibility criteria included clinical trials in humans with at least 12 months of follow-up comparing the failures rates between occlusal and occlusoproximal amalgam and composite resin restorations. Clinical questions were formulated and organized according to the PICOS strategy. SOURCE An electronic search without restriction on the dates or languages was performed in PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, and Web of Science up until March 2015. STUDY SELECTION The initial search resulted in 938 articles from PubMed/MEDLINE, 89 titles from the Cochrane Central Register of Controlled Trials, and 172 from the Web of Science. After an initial assessment and careful reading, 8 studies published between 1992 and 2013 were included in this review. According to the risk of bias evaluation, all studies were classified as high quality. CONCLUSIONS The results of this review suggest that composite resin restorations in posterior teeth still have less longevity and a higher number of secondary caries when compared to amalgam restorations. In relation to fractures, there was no statistically significant difference between the two restorative materials regarding the time of follow-up. CLINICAL SIGNIFICANCE There is currently a worldwide trend towards replacing amalgam restorations with mercury-free materials, which are adhesive and promote aesthetics. It is important to perform an updated periodic review to synthesize the clinical performance of restorations in the long-term.

Depth of cure of dental composites submitted to different light-curing modes

Objective: This study evaluated the depth of cure of five dental composites submitted to different light-curing modes. Material and Methods: Canal-shaped cavities with 5mm of length were prepared on the buccal surfaces of extracted third molars, and restored using P-60, A-110, Admira, Z-250 and Supreme resin composites. Materials were light-cured from the top, according to three modes (Group 1- Conventional (C): 500 mW/cm2/ 40 s; Group 2 – Soft-Start (SS):250 mW/cm2/ 20 s + 500 mW/cm2/ 20 s + 500 mW/cm2/ 10 s and Group 3 – LED: 250 mW/cm2/ 40 s). After that, cavity longitudinal surfaces were polished and marked with a millimeter scale of 4mm of length. Depth of cure was evaluated by means of Knoop hardness number (KHN), so that five indentations were performed at each millimeter. Original data were submitted to three-way ANOVA and Fishers LSD test (α = 0.01). Results: All materials presented a significant reduction on KHN from first to third millimeter. Regarding depth of cure, the results obtained for Conventional and Soft-Start modes were similar, but statistically superiors to those found for group 3 (LED). Conclusion: This performance may be related to the differences among energy densities obtained with different light-curing modes.