LAUSR

OBJECTIVES To investigate the effects of the level of pre-treatment tooth wear and increasing the VDO on the performance of direct resin composite restorations for the rehabilitation of pathological tooth wear. METHODS Full-mouth (pre-treatment) grading was performed on digital greyscale scan records for 34 participants (35.3 ± 8.4 years) with signs of moderate-to-severe generalised tooth wear, using the Tooth Wear Evaluation System and the Basic Erosive Wear Examination. Each participant received full-mouth direct resin composite restorations, with increased VDO. The post-treatment increase in the VDO was determined. Recalls were planned after 1 month, and after 1, 3, and 5 years. Three 'levels' of restoration failure were described. The effects of the variables on the frequencies of restoration failure were calculated with a multivariable Cox regression, (p < 0.05). RESULTS 1269 restorations were placed with a mean observation period of 62.4 months. Increasing the VDO by 1mm significantly reduced the risks of all levels of anterior restoration failure (HR ≤ 0.62, p ≤ 0.025). A higher anterior BEWE surface score was associated with increased risks of Level 2- & 3- failures, (HR ≥ 1.29, p ≤ 0.019). Premolar restorations showed lower risks of Level 2- & 3- failure, compared to the molar restorations, (HR ≤ 0.5, p ≤ 0.005). CONCLUSION Levels of pre-treatment wear and the applied change in the VDO significantly affected failure risk. CLINICAL RELEVANCE Direct resin composite restorations for the rehabilitation of wear should be made as voluminous as possible, respecting the presenting biological, functional, and aesthetic constraints.