IADR Abstract Archives
Three-Dimensional Analysis Reveals Significant Variability in Undergraduate Full-Veneer-Crown Preparation Quality
Objectives: The aim of this cross-sectional study was to determine the quality of full-veneer-crown (FVC) preparations produced by supervised undergraduate students at a UK dental teaching hospital.
Methods: One hundred and eighty-five stone dies of FVC preparations (126 full-metal, 39 metal-ceramic and 20 ceramic; 16 anterior and 169 posterior; 87 mandible and 98 maxilla); produced between October 2019 and March 2021 by dental students; were scanned into 3D imaging software (Exocad). Using cross-sections obtained in the mesio-distal (M-D), bucco-lingual (B-L), mesiobuccal-distolingual (MB-DL), and distobuccal-mesiolingual (DB-ML) planes, the following parameters were evaluated: total angle of convergence (TOC), abutment height and margin design and depth. Statistical comparisons were made by plane, location, material type, tooth type, and inter- and intra-arch positions using Mann-Whitney U and Kruskal-Wallis with post-hoc Bonferroni-corrected Dunn’s tests, as appropriate (α = 0.05). Assessor reliability was evaluated with intra- and inter-class correlation coefficients.
Results: Across all preparations the mean TOC was 24.8° ± 11.7°, with the DB-ML plane displaying the greatest taper (26.6° ± 15.0°) (p <0.05). Mandibular and molar teeth were significantly more tapered (p <0.001) and exhibited significantly shorter abutment heights (p <0.001). The mean abutment height was 3.6mm ± 1.0mm, with the mesial location illustrating the shortest abutment height (2.8mm ± 1.1mm) (p <0.001). Full-metal (3.4mm ± 0.8mm) and ceramic (3.4mm ± 1.3mm) preparations were significantly shorter than metal-ceramic preparations (4.1mm ± 1.0mm) (p <0.001). No significant difference in TOC or abutment height was observed for FVC preparations on the left or right. Chamfer margins were the most frequently observed and mean margin depths ranged from 0.49–1.06mm.
Conclusions: The findings from this study suggest that undergraduate students in a dental school teaching environment produce sufficient FVC preparations for incisor, canine and premolar teeth, but over-tapered molar preparations with short abutment heights.
Methods: One hundred and eighty-five stone dies of FVC preparations (126 full-metal, 39 metal-ceramic and 20 ceramic; 16 anterior and 169 posterior; 87 mandible and 98 maxilla); produced between October 2019 and March 2021 by dental students; were scanned into 3D imaging software (Exocad). Using cross-sections obtained in the mesio-distal (M-D), bucco-lingual (B-L), mesiobuccal-distolingual (MB-DL), and distobuccal-mesiolingual (DB-ML) planes, the following parameters were evaluated: total angle of convergence (TOC), abutment height and margin design and depth. Statistical comparisons were made by plane, location, material type, tooth type, and inter- and intra-arch positions using Mann-Whitney U and Kruskal-Wallis with post-hoc Bonferroni-corrected Dunn’s tests, as appropriate (α = 0.05). Assessor reliability was evaluated with intra- and inter-class correlation coefficients.
Results: Across all preparations the mean TOC was 24.8° ± 11.7°, with the DB-ML plane displaying the greatest taper (26.6° ± 15.0°) (p <0.05). Mandibular and molar teeth were significantly more tapered (p <0.001) and exhibited significantly shorter abutment heights (p <0.001). The mean abutment height was 3.6mm ± 1.0mm, with the mesial location illustrating the shortest abutment height (2.8mm ± 1.1mm) (p <0.001). Full-metal (3.4mm ± 0.8mm) and ceramic (3.4mm ± 1.3mm) preparations were significantly shorter than metal-ceramic preparations (4.1mm ± 1.0mm) (p <0.001). No significant difference in TOC or abutment height was observed for FVC preparations on the left or right. Chamfer margins were the most frequently observed and mean margin depths ranged from 0.49–1.06mm.
Conclusions: The findings from this study suggest that undergraduate students in a dental school teaching environment produce sufficient FVC preparations for incisor, canine and premolar teeth, but over-tapered molar preparations with short abutment heights.