Clinical Effectiveness of Cervical Restorations - A Meta-Analysis

Objectives: To carry out a meta-analysis in order to assess the influencing factors on retention loss and marginal discoloration of cervical restorations made of composites and glass ionomer (derivates). Materials and Methods: The literature was searched for prospective clinical studies on cervical restorations with an observation period of at least 18 months. Results: Fifty clinical studies involving 40 adhesive systems matched the inclusion criteria. On average, 10% of the cervical fillings were lost and 24% exhibited marginal discoloration after 3 years. The variability ranged from 0% to 50% for retention loss and from 0% to 74% for marginal discoloration. Hardly any secondary caries was detected. When linear mixed models with a study and experiment effect were used, the analysis revealed that the adhesive/restorative class had the most significant influence, with two-step self-etching adhesive systems performing best and one-step self-etching adhesive systems performing worst; three-step etch-and-rinse systems, glass ionomers/resin-modified glass ionomers, two-step etch-and-rinse systems and polyacid-modified resin composites were ranked in between. Restorations placed in teeth whose dentin had been prepared showed a statistically significant higher retention rate than those placed in teeth with unprepared dentin (p<0.05). Bevelling of the enamel and the type of isolation used (rubber dam/cotton rolls) had no significant influence. Conclusion: The clinical performance of cervical restorations was significantly influenced by the type of adhesive system used and/or the adhesive class to which the system belonged and whether the dentin was prepared or not.