The reliability of an easy measuring method for abutment convergence angle with a computer-aided design (CAD) system

• Published in: The journal of advanced prosthodontics Vol. 6; no. 3; pp. 185 - 193
• Main Authors: Seo, Yong-Joon, Kwon, Taek-Ka, Han, Jung-Suk, Lee, Jai-Bong, Kim, Sung-Hun, Yeo, In-Sung
• Format: Journal Article
• Language: English
• Published: Korea (South) The Korean Academy of Prosthodontics 01.06.2014; 대한치과보철학회
• Subjects: Original; 치의학; Computer-aided design; Convergence angle; Prosthodontic tooth preparation; Dental abutments; Validation studies
• ISSN: 2005-7806; 2005-7814
• DOI: 10.4047/jap.2014.6.3.185

The purpose of this study was to evaluate the intra-rater reliability and inter-rater reliability of three different methods using a drawing protractor, a digital protractor after tracing, and a CAD system. Twenty-four artificial abutments that had been prepared by dental students were used in this study. Three dental students measured the convergence angles by each method three times. Bland-Altman plots were applied to examine the overall reliability by comparing the traditional tracing method with a new method using the CAD system. Intraclass Correlation Coefficients (ICC) evaluated intra-rater reliability and inter-rater reliability. All three methods exhibited high intra-rater and inter-rater reliability (ICC>0.80, P<.05). Measurements with the CAD system showed the highest intra-rater reliability. In addition, it showed improved inter-rater reliability compared with the traditional tracing methods. Based on the results of this study, the CAD system may be an easy and reliable tool for measuring the abutment convergence angle.