Comparison of Intraoperative Pain Perception During Caries Excavation Using Smart Burs and Carisolv to Conventional Diamond Burs

Dental caries is a biofilm-mediated disease in which the progression of the carious lesion results in the demineralization and structural breakdown of dental hard tissues. Contemporary operative dentistry emphasizes minimally invasive management, with the selective removal of irreversibly damaged, infected dentin while preserving tissue that may remain structurally and biologically capable of repair. The choice of caries excavation technique may influence the amount of sound tooth structure removed, the mechanical stimulation of dentin, treatment time, and patient comfort.

Conventional rotary excavation is commonly performed using diamond or carbide burs. Although effective, rotary instrumentation may involve unnecessary removal of sound or potentially remineralizable dentin and can produce mechanical and thermal stimuli that may contribute to discomfort during treatment. Alternative excavation methods have therefore been developed to achieve more selective removal of carious tissue.

Smart polymer burs are designed to selectively remove softer, infected dentin while minimizing cutting of harder, sound dentin. The burs are manufactured from a polymer material with a hardness intermediate between infected and sound dentin. They are used at low rotational speed and are intended to reduce unnecessary removal of tooth structure. When the bur encounters harder dentin, its cutting efficiency is reduced, thereby supporting a more conservative excavation approach.

Carisolv is a chemomechanical caries-removal system. Its gel formulation contains sodium hypochlorite together with amino acids and is intended to soften altered carious dentin. Following chemical softening, the softened tissue is removed with appropriate hand instrumentation. The technique is based on selective removal of carious tissue rather than conventional high-speed mechanical cutting.

The present study is designed as a three-arm, parallel-group randomized clinical trial. After assessment and enrollment, participants will be allocated to one of three intervention groups using a simple randomization procedure. The intervention will be performed on the eligible carious tooth according to the assigned excavation technique. The same clinical operator or appropriately trained operator will follow a standardized protocol for the respective technique to minimize variation in treatment delivery.

For the Smart-bur group, carious dentin will be excavated using the designated polymer bur with a slow-speed handpiece according to the manufacturer's recommended operating conditions. For the Carisolv group, the Carisolv gel will be applied to the carious dentin according to the manufacturer's instructions, allowed to act on the affected tissue, and the softened carious material will subsequently be removed using suitable hand instruments. For the conventional group, caries will be excavated using conventional diamond burs with rotary instrumentation according to routine operative dentistry principles.

Radiographic and clinical assessment will be used before treatment to confirm the suitability of the selected tooth and to reduce the likelihood of including teeth with pulpal involvement. Treatment will be carried out under standardized clinical conditions. Participants will be monitored throughout the procedure, and the assigned excavation technique will be discontinued or modified if clinically indicated for patient safety or appropriate dental treatment.

Baseline demographic and relevant clinical information will be documented on a standardized data-collection form. Treatment allocation and study-related observations will be recorded by the research team under appropriate supervision. Data will subsequently be entered into a statistical database for analysis.

The principal analytical comparison will assess whether the three excavation techniques differ in the level of pain reported during the caries-removal procedure. Continuous variables will initially be summarized using appropriate descriptive statistics. Distributional assumptions will be assessed before selection of the final comparative statistical test. For normally distributed data, one-way analysis of variance will be used to compare the three independent groups. If the assumptions for parametric analysis are not satisfied, an appropriate non-parametric alternative will be considered. Statistical significance will be assessed at an alpha level of 0.05.

The study is intended to provide clinical evidence regarding the effect of different caries excavation approaches on patient comfort and to contribute to the evidence base for minimally invasive operative dentistry. The findings may help clinicians understand whether selective polymer-bur or chemomechanical excavation techniques provide a clinically meaningful difference in patient-reported discomfort compared with conventional rotary excavation.