TANAKA AND JOHNSTON'S MIXED DENTITION VALIDITY: AN ANALYSIS AMONG YEMENI ADULTS IN SANA'A CITY
Keywords:adults, mixed dentition, regression equations, Tanaka-Johnston analysis, Yemen
Introduction and objective: Mixed dentition space analysis methods via Tanaka-Johnston analysis are regularly used all over the world. Conversely, the appropriate of this analysis between different ethnic groups is dubious. The study aimed to test the appropriate of the Tanaka-Johnston analysis for Yemeni adults and to arise regression equations designed for Yemen population if needed.
Methods: The study included two hundred and twenty-seven (106 males and 121 females) Yemenis from Sana'a University, University of Science and Technology, and Al-Rehab Private Clinic. The mesiodistal widths of the four permanent lower canines, incisors, and premolars for the entire quadrants were determined with a digital caliper to the nearest 0.01 mm. To compare average presentation values derived from this study with values derived using Tanaka-Johnston equations, Student's paired t-test was used, as well as the chi-square (χ2) test used for appropriateness of fit.
Result: Gender differences were observed in the total mesiodistal width of both canines and premolars in both arches as revealed by the t-test (p < 0.001). The sum of the actual mesiodistal width of the canines and premolars was compared with the expected widths derived from the Tanaka and Johnston equation and significant differences (p<0.001) were found. Regression analysis indicated that the sum of the mesiodistal width of the permanent mandibular incisors is a good predictor of that of un-erupted canines and premolars, with correlation coefficients ranging from 0.51 to 0.61. Accordingly, two linear regression equations were developed to predict tooth width for Yemeni males and females.
Conclusion: It was concluded from this study that the Tanaka-Johnston analysis did not accurately predict the mesiodistal width of the unruptured canines and premolars of the Yemeni population. Moreover, new regression equations have been developed for the research sample that can be a standard for Yemen. However, further studies must be performed to verify the applicability and accuracy of these equations.
Peer Review History:
Received: 4 November 2021; Revised: 3 December; Accepted: 31 December, Available online: 15 January 2022
Average Peer review marks at initial stage: 6.5/10
Average Peer review marks at publication stage: 7.5/10
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