An in vitro assessment of the residual dentin after using three minimally invasive caries removal techniques

Abstract

Abstract To evaluate the efficiency and effectiveness of three minimally invasive MI caries removal techniques for removing deep dentin carious lesions. Forty extracted carious molars were treated by conventional rotary excavation (control), chemomechanical agent (Brix 3000), ultrasonic abrasion (Woodpecker, Guilin, China); and Er, Cr: YSGG laser (Biolase™ San Clemente, CA). The assessments include; the excavation time, Diagnodent pen, Raman spectroscopy, Vickers microhardness, and scanning electron microscope combined with energy dispersive X-ray spectroscopy (SEM-EDX). The rotary method recorded the shortest excavation time (p < 0.000), Brix 3000 gel was the slowest. All techniques removed the infected tissues completely as the Diagnodent pen readings were < 20 and laser-ablated surfaces recorded the lowest reading. The bur-excavated dentin showed higher phosphate and lower matrix contents with higher tissue hardness that were comparable to sound dentin indicating the non-selectiveness of this technique in removing the potentially repairable dentin tissue. In contrast, the MI techniques exhibited lower phosphate and higher organic contents associated with lower microhardness in the deeper dentin layers. This was associated with smooth residual dentin without smearing and patent dentinal tubules. This study supports the efficiency of these MI methods to be a conservative alternative to rotary excavation, providing a promising strategy for the clinical dental practice.