White-opaque flowable composite liner as a depth marker in composite restorations prevents tooth substance loss in filling removal: a randomized double-blinded in vitro study.

OBJECTIVES: Removal of esthetic restorations leads to loss of tooth structure and the extent of the loss is difficult to estimate due to exact-shade matching. This randomized double-blinded in vitro study aimed examining the influence of a white-opaque flowable composite depth marker as an optical removal aid for tooth substance preservation and shortened restoration removal time. MATERIALS AND METHODS: Class II cavities (n = 100) in extracted healthy mandibular molars (n = 50, two runs) were prepared, filled, and the restoration removed. Tooth weight and volume (before and after) and removal time were measured and remnants visually documented. An optimal tooth shade-matched flowable composite liner was used as control. RESULTS: Tooth structure loss was significantly lower using a white-opaque liner. Mean values for volume/weight loss were 0.037 +/- 0.030 g and 0.016 +/- 0.005 cm(3) (p < 0.01) for white-opaque liner; 0.067 +/- 0.000 g and 0.028 +/- 0.003 cm(3) (p < 0.01) for tooth-colored composite. Removal time and number of pulp chamber perforations showed no significant differences (p = 0.80). CONCLUSIONS: Within the limitations of this randomized double-blinded in vitro study, the use of a white-opaque flowable liner as a depth marker may provide the practitioner a visual aid in the replacement of a composite restoration and may protect against tooth structure loss. CLINICAL RELEVANCE: When restoration replacement is indicated, removal of esthetic restorations often causes tooth structure loss due to difficult optical color matching. Using a white-opaque flowable liner as a depth marker clinically aids in restoration removal and protects against tooth structure loss.