Clinical and In-vitro Evaluation of Posterior Composites Wear: Five-year RCT

Objectives:  To determine at 5-year follow-up of a randomised-clinical-trial (RCT), the clinical performance, bio-tribo-corrosive wear behaviour and worn-surface topography of nano-composite Filtek-Supreme (3M-ESPE) and monomodal-compact-filled-composite-resin Z100 (3M-ESPE) restorations.

Methods: 18 Filtek-Supreme and 18 Z100 restorations were placed in upper/lower molars and bonded with Single-bond-Adhesive (3M-ESPE). Restorations were evaluated at baseline, and at 6-12-24-36-48-60-months of clinical service according to USPHS-criteria. At recalls, gypsum-replicas were used for 3D-Pro-laser-scanning (Willytec-Munich) to quantify wear by measuring vertical, volumetric loss of enamel and composites and araldite-epoxy-resin-replicas for scanning-electron-microscopy (SEM) analysis (Philips-XL20) of worn-surface.

Results: The recall rate at 5-year follow-up was 100% and major failure requiring restoration replacement was not observed. While the polishability of Filtek-Supreme restorations was significantly better than Z100 (p<0, 05), both types of restorations showed significantly decreased (p<0, 05) alpha scores for colour match (Filtek-Supreme-10%, Z100-12%) and marginal degradation (Filtek-Supreme-4%, Z100-5%) at 5-years. No significant differences were observed for other criteria. Wear data presented enamel-like vertical loss but volume loss of both restoration types was significantly higher (p<0, 05) than that of enamel, due to the greater composite-surface-area versus enamel-surface-area. Furthermore, volume loss of Z100 was significantly higher (p<0, 05) than that of Filtek-Supreme restorations. This is related to differences in friction properties. SEM explained relative differences in vertical and volume loss behaviour.

Mean and standard-deviation of wear of composites versus enamel

Parameters	Z100	Filtek-Supreme
Volume loss (mm3)
Total-Surface-Volume loss	-3,5±1,2	-1,0±6,0
Enamel-Surface-Volume loss	-1,2±4,1	-0,4±0,2
Restoration-Surface-Volume loss	-2,3±8,3	-1,0±0,4
Vertical loss (µm)
Enamel (heavy-occlusal-contact-area)	-84±21	-84±21
Enamel (light-occlusal-contact-area)	-55±7	-55±7
Occlusal-contact-areas on restoration	-77±25	-83±26
Marginal degradation (range)	-60 to -560	-60 to -590

Conclusion: The monomodal-compact-filled Z100 and the nanofilled Filtek-Supreme posterior composites used in this study showed very acceptable clinical performance and presented qualitative and quantitative differences in wear behaviour versus human enamel after 5-years of clinical service.