Elemental analysis of caries-affected root dentin and artificially demineralized dentin

Abstract

Elemental analysis of caries-affected root dentin and artificially demineralized dentin

Younghye Sung Program in Conservative Dentistry Department of Dental Science Graduate School, Seoul National University (Directed by Professor Ho-Hyun Son, D.D.S., M.S.D., Ph.D.)

Objectives This study aimed to analyze the mineral composition of naturally- and artificially-produced caries-affected root dentin and to determine the elemental incorporation of resin-modified glass ionomer (RMGI) into the demineralized dentin.

Materials and methods Box-formed cavities were prepared on buccal and lingual root surfaces of extracted sound human premolars (n = 15). One cavity was exposed to a microbial caries model using a strain of Streptococcus mutans. The other cavity was subjected to a chemical model under pH cycling. Premolars and molars with root surface caries were used as a natural caries model (n = 15). Outer caries lesion was removed using a carbide bur and a hand excavator under a dying technique and restored with RMGI (Fuji Ⅱ LC, GC Corp.). The weight percentages of calcium (Ca), phosphate (P), and strontium (Sr) and the widths of demineralized dentin were determined by electron probe microanalysis and statistically analyzed using ANOVA and Tukeys post hoc test (α = 0.05).

Results Demineralized surface was observed under SEM in all samples. Artificial models induced greater losses of Ca and P and larger widths of demineralized dentin than did a natural caries model (p < 0.05). Sr was diffused into the demineralized dentin layer from RMGI.

Conclusions Both the microbial and the chemical caries models produced similar patterns of mineral composition on the caries-affected dentin. However, within the limitation of this study, the artificial lesions had a relatively larger extent of demineralization than the natural lesions. Sr from RMGI was incorporated into the superficial layer of the caries-affected dentin.