Affiliations: Private practice, Scottsdale AZ, formerly Graduate Prosthodontics, Indiana University School of Dentistry, Indianapolis, IN, USA | Dental Materials, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, IN, USA | Department of Statistics, Purdue University, West Lafayette, IN, USA | Research Analyst, Oral Health Research Institute, Indiana University School of Dentistry, Indianapolis, IN, USA
Note: [] Corresponding author: Dr. Yoshiki Oshida, PhD, Professor, Dental Materials Division, Department of Restorative Dentistry, Indiana University School of Dentistry, 1121 West Michigan Street, Indianapolis, IN 46202-5186, USA. Tel.: +1 317 274 3725; Fax: +1 317 278 7462; E-mail: yoshida@iupui.edu.
Abstract: Background: A new approach called “minimum intervention” has been introduced for restoration of carious lesions to preserve tooth structure. This approach suggests that perhaps caries need not always be removed completely from deeper portions of the cavity. It is, therefore, important to characterize caries-affected dentin structures, because of the potential changes in bonding quality when using different dentinal substrates. Materials and method: Ninety teeth (30 teeth each group) were studied. The first group (CF) consisted of 30 caries-free teeth. The second group (CC) consisted of 30 teeth, for which caries-free dentin teeth was chemically demineralized. The third group (ND) consisted of 30 extracted human molars with coronal carious lesions. After all tooth samples were water-polished with grit #600 SiC paper, they were tested by surface contact angle measurements and the electron-probe microanalyzer to measure Ca/P mol ratio. Results: Contact angles were CF=60.07°; CC=30.8°; ND=26.11°, p<0.05. Ca/P mol ratios were as follows; CF=1.549 (±0.0435); CC=1.324 (±0.2305); ND=1.568 (±0.0523), p<0.05. Weibull analyses for Ca/P mol ratio indicated shape parameter (m) of CF was 13.3; it was 12.8 for ND and 11.8 for CC. Above the δ point (=1.65 in Ca/P ratio), for both groups m=3.4. Conclusion: Caries-affected dentin surfaces (naturally-developed and chemically created) were statistically more chemically active than caries-free dentin surface. Ca/P mol ratio of chemically created caries was less than other two groups.
Keywords: Minimum intervention, caries-affected dentin, caries-free dentin, characterization, Ca/P ratio
