Mohammad Hossein Toodehzaeim1, Hossein Aghili1, Elham Shariatifar2, Mahboobe Dehghani3. 1. Assistant Professor, Department of Orthodontics, Faculty of Dentistry Shahid Sadoughi University of Medical Sciences, Yazd, Iran. 2. Dentist, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. 3. Assistant Professor, Dental Research Center, Department of Orthodontics, Faculty of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran, Phone: +98 (511) 8829501, Fax: +98 (511) 8829500, e-mail: dehghanimm@mums.ac.ir.
Abstract
AIMS: Prediction of the mesiodistal crown width of unerupted canines and premolars is an important aspect of mixed dentition analysis. The accuracy of Tanaka-Johnston equations, the most commonly method, is questionable when it is applied to different ethnic groups. In this study, we aimed to develop a new regression equation for this prediction in an Iranian population. MATERIALS AND METHODS: The dental casts of 120 Iranian subjects with complete permanent dentition were selected. Mesiodistal crown widths of teeth were measured with digital caliper. In the first part of the study, the correlation and linear regression equations between four mandibular incisors and the canine-premolars segments of both arches were developed (modified Tanaka-Johnston equation). In the second part, as a new method, correlation and linear regression equations were developed between the sum of mandibular central incisors-maxillary first molars and the canine-premolars segments. RESULTS: It was found that the correlation coefficients between the sum of mandibular central incisors-maxillary first molars and the maxillary and mandibular canine-premolars segments were higher (r = 0.66, 0.68 respectively) than the one between the four mandibular incisors and the canine-premolars segments (r = 0.58. 0.64). CONCLUSION: New linear regression equations were derived. In this study, the sum of mandibular central incisors and maxillary first molars was better predictor for unerupted canines and premolars. This novel approach allows the prediction of width of unerupted canines and premolars to take place at earlier age. CLINICAL SIGNIFICANCE: Using the new method, orthodontists could take advantage of mixed dentition analysis at earlier age. Moreover, to test the derived equations on a larger sample size and in other ethnicities is highly recommended.
AIMS: Prediction of the mesiodistal crown width of unerupted canines and premolars is an important aspect of mixed dentition analysis. The accuracy of Tanaka-Johnston equations, the most commonly method, is questionable when it is applied to different ethnic groups. In this study, we aimed to develop a new regression equation for this prediction in an Iranian population. MATERIALS AND METHODS: The dental casts of 120 Iranian subjects with complete permanent dentition were selected. Mesiodistal crown widths of teeth were measured with digital caliper. In the first part of the study, the correlation and linear regression equations between four mandibular incisors and the canine-premolars segments of both arches were developed (modified Tanaka-Johnston equation). In the second part, as a new method, correlation and linear regression equations were developed between the sum of mandibular central incisors-maxillary first molars and the canine-premolars segments. RESULTS: It was found that the correlation coefficients between the sum of mandibular central incisors-maxillary first molars and the maxillary and mandibular canine-premolars segments were higher (r = 0.66, 0.68 respectively) than the one between the four mandibular incisors and the canine-premolars segments (r = 0.58. 0.64). CONCLUSION: New linear regression equations were derived. In this study, the sum of mandibular central incisors and maxillary first molars was better predictor for unerupted canines and premolars. This novel approach allows the prediction of width of unerupted canines and premolars to take place at earlier age. CLINICAL SIGNIFICANCE: Using the new method, orthodontists could take advantage of mixed dentition analysis at earlier age. Moreover, to test the derived equations on a larger sample size and in other ethnicities is highly recommended.
Authors: Nduguyu Kerre; James Lwanga Ngesa; Peter Ng'ang'a; Arthur Musakulu Kemoli; Janella Bermudez; Ana Lucia Seminario Journal: BMC Oral Health Date: 2022-08-09 Impact factor: 3.747