Microhardness and Ca:P ratio of carious and Carisolv™ treated caries-affected dentine using an ultra-micro-indentation system and energy dispersive analysis of x-rays -: A pilot study

Background: This study aimed to evaluate microhardness and chemical analysis of carious and caries-affected dentine. The hypothesis tested was that calcium:phosphorous (Ca:P) ratios correlate with microhardness values. Methods: Four carious human third molars were sectioned through the caries lesion in the mesiodistal longitudinal plane. One half of each lesion underwent carious dentine removal using Carisolv(TM) gel. The cut surfaces were polished, microhardness tested using an Ultra-Micro-Indentation System (UMIS) and elemental analysis performed using energy dispersive analysis of x-rays (EDAX). Results: The microhardness of carious dentine decreased gradually towards the cavity floor, but that for caries-affected dentine showed more variation with depth, having a mean hardness of (0.63 +/- 0.18) GPa. Ca:P ratios of carious dentine varied among the four specimens. The mean Ca:P ratio of caries-affected dentine was 1:2.03 +/- 0.08. The hypothesis was accepted for active lesions. Conclusions: The use of Carisolv(TM) to excavate carious tissue can be as effective as rotary instrumentation.