A Comparative Clinical Study Assessing Dentin Thickness and Discoloration in Deep Carious Lesions Treated With Biodentine Alone Versus Diode Laser Pre-treatment Followed by Biodentine

Deep carious lesions present a clinical challenge due to the need to remove infected dentin while preserving pulp vitality and preventing postoperative complications. Contemporary minimally invasive dentistry emphasizes selective caries removal and the use of bioactive materials to promote pulp healing and reparative dentin formation. Biodentine is a calcium silicate-based bioactive cement widely used in vital pulp therapy and indirect pulp capping. It provides favorable sealing ability, biocompatibility, and the potential to stimulate reparative dentinogenesis. However, concerns remain regarding the preservation of dentin thickness and the risk of postoperative tooth discoloration when used in deep cavities. Diode lasers have been introduced as an adjunctive modality in deep caries management due to their antimicrobial effects, ability to achieve hemostasis, and potential to modify dentin surface characteristics prior to placement of restorative materials. Laser pre-treatment may therefore influence clinical outcomes when used before Biodentine application. This randomized controlled clinical trial is designed to compare two treatment approaches for deep carious lesions in vital posterior teeth. In the control group, selective caries removal will be performed followed by placement of Biodentine. In the experimental group, diode laser pre-treatment of the cavity will be applied prior to Biodentine placement. All procedures will be carried out under rubber dam isolation and standardized aseptic conditions. Changes in dentin thickness and radiographic density of the remaining dentin will be evaluated using cone beam computed tomography at baseline and during follow-up visits at 3 and 6 months. Tooth color changes will be assessed using standardized digital photography and spectrophotometric analysis. Pulp vitality will be evaluated using cold testing and electric pulp testing, and periapical clinical status will be assessed through percussion, palpation, and tooth mobility examination. The primary objective of this study is to compare changes in dentin thickness between Biodentine alone and diode laser pre-treatment followed by Biodentine. Secondary objectives include evaluation of radiographic dentin density, tooth color changes, pulp vitality status, and periapical clinical status over a 6-month follow-up period. This study aims to determine whether diode laser pre-treatment provides additional clinical benefit when used prior to Biodentine application in the management of deep carious lesions.