BIOCOMPATIBILITY TESTING OF RESTORATIVE MATERIALS INFLUENCING DENTIN AND PULP

A comparative study was carried out using 27 healthy human bicuspids t hat had been extracted for orthodontic reasons from adolescents 11 - 1 4 years old. A microphotometrical analysis of buccal and lingual odont oblast layer thickness was performed using the SAMBA 2000 system and t he results were submitted to statistical comparison. The buccal odonto blast layer (BOL) was found to be thicker than the lingual odontoblast layer (LOL). These results were independent of age, sex, and tooth po sition iri the dental arch. Moreover, a strong relationship existed be tween the layer thicknesses as linear function on a logarithmic scale. Standards for the evaluation of pulp-dentin biocompatibility are base d essentially upon qualitative or semiquantitative histological criter ia. A method of quantitative evaluation based upon microphotometrical measurements of the thickness of the buccal odontoblast layer, conside red variable, and the lingual odontoblast layer, considered stable, wa s applied to coronal filling materials that had previously been tested by a classic method. Seventy bicuspids extracted from adolescents 11 - 14 years of age whose class-V cavities had been filled in situ with one of four restorative materials, and whose residual dentin thickness was less than 750 mum, were divided into two groups: an intermediate- term group (A) and a long-term group (B); both groups were subdivided into four experimental series as a function of test materials. A micro photometrical analysis was carried out using an automatic scanning sys tem (SAMBA 2000) for the quantification of buccal and lingual odontobl ast layer thicknesses. The results confirmed that due to the stability of the LOL thickness it may legitimately be used as reference in the study of the analogous BOL thickness. The BOL variations seemed propor tional to the biocompatibility of the material tested. The quantitativ e results obtained should provide an accurate comparison of the materi als at a given period of observation and substantiate a follow-up stud y of the evolution of biocompatibility.