Thirty-six months clinical evaluation of an innovative low-shrinkage composite

Objectives: The aim of this study was to clinically evaluate a low-shrinkage composite in posterior restorations in vital teeth.

Material and methods: One hundred class I and II restorations were performed in 50 patients using the composite material Tetric EvoCeram (Ivoclar-Vivadent) and the halogen light-curing lamp Astralis_10 (Ivoclar-Vivadent). In each patient two restorations (split-mouth study design) were made with micro-layering technique: one using low-power curing light (600 mW/cm2 for 20 s), the other, on the opposite arch, using high-power curing light (1200 mW/cm2 for 10 s). Three clinicians took part to this long-term study, two experts (ten years of clinical experience) and a newly graduated (two years of clinical experience) The restoration quality evaluation was carried out by two independent evaluators with more than 80% of clinical agreement. Baseline controls, six-month, twelve-months, twenty-four months and thirty-six months controls were executed by examiners with two independent evaluating systems: USPHS (qualitative) and SQUACE (quantitative). USPHS and SQUACE methods had similar results considering the marginal quality obtained by the two light curing methods

Results: Restorations without an excellent score were split in both curing ways and performed by the inexpert operator. In two cases there was no contact point with the adjacent element. In these cases too, the distribution between the two curing methods was equal. The almost total absence of postoperative sensibility has to be pointed out.

Conclusion: Results evidenced that there are no visible differences between marginal quality obtained with low-power and high-power polymerization. Operators' experience influences marginal adaptation: the most common mistake was marginal overextension (6% in baseline control), which has been corrected during the first recall by finishing. The mid-term data suggest us the possibility to cure composite in posterior teeth both with low power than high power intensity light curing programs.