Color Stability and Wear Resistance of Direct Flowable and Preheated Composite Using the Injectable Technique

Primary outcomes

1. The wear resistance of the injectable flowable composite veneers compared to their preheated resin composites counterparts.

   Time frame: Assessment at baseline, 6 months and 1 year after the restorations of the teeth.

   Participants will be assessed at baseline, directly after the finishing and polishing procedure, and at review visits according to the following criteria:

   -The gypsum replicas will be scanned three-dimensionally using a 3D laser scanner at baseline, 6 months and 12 months of clinical service, to analyse the volumetric material loss, which can be associated with structural wear, using 3D analysis software (Medit Link, Medit, Seoul, Republic of Korea) [28, 29] [30] [31] [32]. Follow up images will be superimposed on baseline images

2. The color stability of the injectable flowable composite veneers compared to their preheated resin counterparts.

   Time frame: Assessment at baseline, 6 months and 1 year after the restorations of the teeth.

   -Shade measurements will be taken at baseline, one week, one month, 3 months and 6 months using the following methods:

   • Using a spectrophotometer (VITA Easyshade V; VITA Zahnfabrik, Bad Säckingen, Germany), color values (L*, a*, b*) according to the Commission Internationale d'Eclairage (CIELab) will be taken at the middle of each restored tooth using a customized jig to fix the position and in the afternoon with sunlight and standardized room illumination and at each evaluation period. The color changes will be determined using the CIEDE2000 formula.
   • Using Vita classical shade guide (Vita Zahnfabrik, Bad Säckingen, Germany) and a professional photograph before treatment, at baseline and at each review visit.