IADR Abstract Archives

Evaluating Clinical Molar Preparations - using the Coordinate Geometry Method

Objective .Many studies have shown that preparations done in practice have geometric parameters that far exceed the recommended values. The important parameters are the total occlusal convergence (TOC) angle, margin width, margin angle, and the abutment height. Given the situation of an all-ceramic complete crown preparation, this study aims to compare the literature recommended values and actual preparations created in general practice using the coordinate geometry method (CGM).

Method . 26 maxillary molar second pour preparations were collected from general practices. The samples were scanned and the buccolingual and mesiodistal cross sectioned images were captured. The image was imported into a custom program utilizing the coordinate geometry method where the geometric parameters were measured and calculated.

Result .The mean TOC angles for the 26 molars far exceeded the recommended values (x̄=30.40 (s=9.34) > 12 degrees). The mean margin widths were below the minimum recommended values (x̄ =0.60 < 1.00 mm), and the mean margin angles were within the recommended values (x̄ =146.15 < 147 degrees).

Conclusion . The CGM provides a comprehensive evaluation of clinical molar preparations. The preparations provided in general practice have parameters that do not meet the minimum requirements according to the recommended values. The values using the CGM can be used in future tests to see how the shortcomings of preparations affect the performance and longevity of a crown.

Division: IADR/AMER General Session
Meeting: 2014 IADR/AMER General Session (Cape Town, South Africa)
Location: Cape Town, South Africa
Year: 2014
Final Presentation ID: 249
Abstract Category|Abstract Category(s): Prosthodontics Research
Authors
  • Tiu, Janine  ( University of Otago, Dunedin, N/A, New Zealand )
  • Al-amleh, Basil  ( University of Otago, Dunedin, N/A, New Zealand )
  • Waddell, John  ( University of Otago, Dunedin, , New Zealand )
  • Duncan, Warwick  ( University of Otago, Dunedin, , New Zealand )
  • SESSION INFORMATION
    Poster Session
    Clinical Studies in Prosthodontics
    06/26/2014