Shafique Hafiza Zobia, Zaheer Rumeesha, Jan Abdullah, Fazal Ayesha
Dr. Hafiza Zobia Shafique, BDS, FCPS-II Trainees, Orthodontics Department, Armed Forces Institute of Dentistry, Rawalpindi, Pakistan.
Dr. Rumeesha Zaheer, BDS, FCPS-II Trainees, Orthodontics Department, Armed Forces Institute of Dentistry, Rawalpindi, Pakistan.
Pak J Med Sci. 2021 Mar-Apr;37(2):345-350. doi: 10.12669/pjms.37.2.3240.
Dental study casts play a vital role in the diagnosis and treatment planning of various orthodontic cases. This study was carried out to compare the tooth widths, arch widths, and arch lengths in Class-I normal dentition to those in Class-I and Class-II crowded dentition in an effort to improve treatment planning and to eventually reduce treatment duration.
Total 170 patients, 12 to 40 years of age with a complete set of permanent teeth till 1 molars; who presented to the Orthodontics Department at Armed Forces Institute of Dentistry (A.F.I.D), Rawalpindi from Sep 2019 to Feb 2020, were included in the study. Non-probability purposive method of sampling was used. The dental casts obtained were used to measure tooth widths, arch widths, and arch lengths. Subjects were classified into Class-I normal and Class-I and Class-II crowded occlusion and comparison of the sum of tooth widths, arch widths, and arch length discrepancies were determined among the three occlusion groups. Data was analyzed in SPSS version 21 and independent samples t-test was used to differentiate the variables of interest.
Out of 170 subjects, 73 (42.9%) subjects had Class-I normal occlusion while 97 (57%) had Class-I and Class-II crowded occlusions. No statistical difference was found between the occlusal groups with regard to the sum of tooth widths, inter-canine widths, inter-first premolar widths, inter-second premolar widths and inter-molar widths. However, a remarkable difference was observed between the occlusal groups with respect to arch perimeters and arch length discrepancies (p = 0.000 and 0.000 respectively).
Results of the current study indicate that crowding of teeth occurs as a consequence of decreased arch perimeters which may lead to increased arch length discrepancies. However, no prominent difference was noticed in the sum of tooth widths and arch widths among different occlusal groups.
牙颌模型在各类正畸病例的诊断和治疗计划中起着至关重要的作用。本研究旨在比较I类正常牙列与I类和II类牙列拥挤患者的牙宽度、牙弓宽度和牙弓长度，以改进治疗计划并最终缩短治疗时间。
选取2019年9月至2020年2月期间在拉瓦尔品第武装部队牙科学院正畸科就诊的170例患者，年龄在12至40岁之间，恒牙列完整至第一磨牙。采用非概率目的抽样法。获取的牙颌模型用于测量牙宽度、牙弓宽度和牙弓长度。将受试者分为I类正常、I类和II类牙列拥挤三组，比较三组间牙宽度总和、牙弓宽度和牙弓长度差异。数据采用SPSS 21版进行分析，使用独立样本t检验来区分感兴趣的变量。
170名受试者中，73例（42.9%）为I类正常咬合，97例（57%）为I类和II类牙列拥挤。在牙宽度总和（尖牙间宽度、第一前磨牙间宽度、第二前磨牙间宽度和磨牙间宽度）方面，咬合组间未发现统计学差异。然而，在牙弓周长和牙弓长度差异方面，咬合组间观察到显著差异（分别为p = 0.000和0.000）。
本研究结果表明，牙弓周长减小会导致牙齿拥挤，进而可能导致牙弓长度差异增加。然而，不同咬合组之间在牙宽度总和和牙弓宽度方面未发现明显差异。
