Axial Contour Alteration following Restorative Treatment: A Systematic Review

Abstract

Purpose: This qualitative systematic review had two aims: (1) evaluation of the impact of restorative treatment on tooth contour, and (2) investigation of the effect of altered tooth contour on biological health.Methods: An electronic search was conducted using PubMed (MEDLINE), Cochrane Library and Google Scholar. A combination of relevant key words was applied. The search was completed in October 2015 and was confined to peer-reviewed studies published in English. Results:The initial search had disclosed a total of 1057 studies; however, after applying the inclusion criteria, only 12 studies were suitable for inclusion. The studies had revealed that the axial tooth contour is vulnerable to increasing following restorative treatment. The axial contour tends to increase gradually as the distance from the gingival margin increases. Still, the contour increase was within the anatomical range. There were signs that increased tooth contour was associated with negative biological consequences. However, a clear relationship between contour increase and the biological consequences was not apparent. There were indications that the observed negative consequences may be related to restorative variables such as plaque retentiveness and subgingival margin placement. Conclusions:As the contour increase appears to be very likely to occur after restorative treatment, and the negative biological consequences cannot be solely attributed to the contour increase, it can be concluded that reasonable contour alteration is acceptable. The key factors that will reduce the negative consequences are cleansability and the maintenance of a healthy restoration-soft tissue relationship.

Developing an All‐Digital Workflow for Dental Skills Assessment: Part II, Surface Analysis, Benchmarking, and Grading

“…Selection of a reference standard tooth is an arbitrary institutional decision, and for purposes of this study, we selected the typodont tooth as having representative morphologic contours, adequately representing those that would function harmoniously in the virtual patient "mouth." [7][8][9][10][11][12][15][16][17][18][19][20][21][22] Using individual aspect clinical data to reine the tolerance to ±0.38 mm allows a single value to be applied to the entire surface, which simpliies the digital grading worklow. Initially, we uniformly applied a ±0.50 mm surface contour tolerance comparable to that reported by McPherson et al to each aspect of the tooth.…”

“…[7][8][9][10][11][12] Each of the deined surface contours of the reference tooth (mesial proximal, distal proximal, facial axial, lingual axial, and occlusal) was digitally segmented, and the total surface area in each segment was computed using Autodesk Meshmixer (www.meshmixer.com; Figure 1). This tolerance was subsequently reined to ±0.38 mm following a survey of peer-reviewed literature to determine clinically acceptable thresholds that, if exceeded, would lead to biological or biomechanical morbidities.…”

“…This tolerance was subsequently reined to ±0.38 mm following a survey of peer-reviewed literature to determine clinically acceptable thresholds that, if exceeded, would lead to biological or biomechanical morbidities. [7][8][9][10][11][12] Each of the deined surface contours of the reference tooth (mesial proximal, distal proximal, facial axial, lingual axial, and occlusal) was digitally segmented, and the total surface area in each segment was computed using Autodesk Meshmixer (www.meshmixer.com; Figure 1). A single, weighted average tolerance was then computed for the entire surface based on the allowable segment tolerances derived from the literature.…”

Developing an All‐Digital Workflow for Dental Skills Assessment: Part I, Visual Inspection Exhibits Low Precision and Accuracy

“…This tolerance was derived from peer-reviewed clinical literature, considering clinically acceptable thresholds for morphologic contour deviation by surface, before biological or biomechanical morbidities are observed to occur. [7][8][9][10][11][12] For example, Abduo's systematic review noted little periodontal impact from axial surface over contour in the gingival third until a value of 0.50 mm was reached; at that point, an increase in plaque retention, gingivitis, and attachment loss was observed. 7 By contrast, that study found that occlusal surface variation was generally less accommodating, based on histological measurements of the periodontal ligament width, which ranges from approximately 0.15 mm on average at mid-root to 0.25 mm at root apex.…”

Subjective Differences between Dentists and Patients about Relative Quality of Metal Ceramic Restorations placed in the Esthetic Zone

“…This could be explained by the fact that maxillary canines are difficult to prepare due to different morphology and line angles. In a review conducted by Abduo, 25 he concluded that axial contour alteration is inevitable after restorative treatment. The alterations were mainly in the form of increasing the contour, which appears to be associated with negative biological consequences.…”