Narrowing of the radicular pulp space in coronally restored teeth

Narrowed radicular pulp spaces are frequently observed in teeth wearing extended restorations. The present study investigates whether the narrowing of particularly the radicular pulp space can be attributed to coronal restorations. The study is based on an anonymized copy of the cone-beam computed tomography (CBCT) database from the Center of Dental Medicine of the University of Zurich. One hundred CBCT scans were selected out of 7317 data sets to match either a crowned (group A; n = 50) or a filled tooth (group B; n = 50) with a contralateral healthy, unrestored, and caries-free control tooth at the same position, respectively. Cross-sectional images were adjusted in the coronal, middle, and apical root third of each subjected tooth. Screenshots were taken in that position and analyzed. The area occupied by the pulp space was determined as percentage area of the whole root diameter on each cross section. The resulting values were compared between restored and control teeth. In both groups (crowned and filled teeth) and in all the three root thirds, the radicular pulp space was significantly narrower in the restored teeth compared to the control teeth. The strongest narrowing effect was observed in the coronal root third and it decreased towards the apical root third (both groups). Teeth with coronal restorations show within the limitations of the present study a significant narrowing of their radicular pulp space. The asserted narrowing could have a complicating effect if root canal treatment becomes necessary in those teeth.