2023 年 32 巻 3 号 p. 191-196
Recent years have seen attempts to perform access cavity preparation in a minimally invasive manner from the standpoint of preserving the tooth substance. However, age-related changes in pulp cavity morphology are unavoidable and may sometimes hinder the operator. Few studies appear to have addressed these changes in detail. The aim of this study was to identify age-related differences in the side walls of the pulp chamber for access cavity preparation using ultra-high-resolution micro-computed tomography (micro-CT). Specimens were human extracted maxillary first molars showing no caries, attrition, or abrasion, classified by age at extraction into adult (age 21-40 years, n=20), middle-aged (age 41-60 years, n=20), and senior (age ≥61 years, n=22) teeth. Specimens were scanned by micro-CT, with the resulting data used to create 3-dimensional (3D) reconstructions for examination of pulp cavity morphology. We also measured dentin thickness using reference lines and measurement lines, and compared the differences between age groups. The observations and measurements of dentin thickness made using these 3D reconstructions showed that in senior teeth, narrowing of the pulp cavity between the mesial and distal side walls was evident from the midline to the pulp chamber floor compared with adult teeth. Narrowing of the pulp cavity was also evident from immediately below the midline of the distobuccal wall to the pulp chamber floor. The dentin thickness of each side wall was measured, and the results showed that senior teeth were significantly thicker than adult teeth in the mesial, distal and distopalatal side walls. These results suggest that when preparing access cavity in senior patients, it is necessary to remove the distobuccal side wall in addition to the mesial and distal side walls for identification of canal orifice in maxillary first molar.
