Eight-year clinical evaluation of two types of resin composite in non-carious cervical lesions.

Objectives: In this clinical study, the 8-year clinical performances of a flowable resin composite was compared with that of a conventional resin composite. Materials and methods: Ninety non-carious cervical lesions (NCCLs) in 19 participants were involved in this trial. NCCLs were restored with a flowable composite (Clearfil Flow FX: FX, Kuraray Noritake, Japan) or a conventional resin composite (Clearfil AP-X: AP) in conjunction with a one-step self-etch adhesive (Clearfil S3 Bond). Each participant had both types of resin composite restorations that were randomly allocated. The restorations were evaluated at baseline and annually up to 8 years using modified USPHS criteria. The data were statistically analyzed using the Fisher's exact test, Kaplan–Meier method, and a multivariate Cox-regression with frailty models (p < 0.05). Results: The 8-year participant recall rate was 95%. One hundred percent retention was recorded for AP, whereas four out of 46 restorations were lost for FX during the 8 years. The incidence of marginal staining increased over time regardless of the type of resin composite, showing 48% for AP and 57% for FX after 8 years. Wear of the resin composite occurred only for the flowable material and there was a significant difference between the types of resin composite (p = 0.024). Overall survival rates at 8 years for AP and FX were 98% and 82% respectively (p = 0.110). Conclusions: The flowable resin composite presented lower wear resistance and showed a lower survival rate compared with the conventional composite after eight years of clinical service. Clinical relevance: Flowable resin composites may show greater wear after long-term clinical service. Trial registration number: UMIN000028745, Date of registration: August 19, 2017. [ABSTRACT FROM AUTHOR]