Kannabiran Praveena, Thirukonda Gnanasagar J, Mahendra Lodd
Department of Orthodontics, King Saud University Dental College and Hospital, Riyadh, Saudi Arabia.
Indian J Dent Res. 2012 Jan-Feb;23(1):53-8. doi: 10.4103/0970-9290.99039.
There has always been a constant search for the definition of idealistic and realistic orthodontic treatment goals for different ethnic groups around the world. This study was hence devised to study the mesio-distal angulations and labio-lingual inclinations of the clinical crowns in Dravidian population with pleasing profiles and non-orthodontic normal occlusion.
Forty dental casts from a Dravidian sample (21.5 years) with Class I canine and molar relation; normal maxillo-mandibular relationship; well-aligned arches; with no dental anomaly, restorations or attrition; no history of previous orthodontic treatment, and exhibiting normal growth were studied. A custom-made tip-torque device was used to measure the crown angulations and inclinations. The arithmetic mean and standard deviations for each tooth type were compared with those of Andrew's Caucasian norms using Student's 't' test.
The study group exhibited statistically significant decrease in crown angulation (mesial tip) and increased labial crown torque in both upper and lower anteriors. The lower anteriors exhibited distal crown tip while the posteriors were significantly tipped more mesially. All the posteriors demonstrated increased lingual crown torque.
Tip and torque modifications are suggested for the fine finishing and easy retention of occlusion in Dravidians while using straight wire appliance.
一直以来，人们不断探寻世界各地不同种族理想与现实的正畸治疗目标的定义。因此，本研究旨在研究达罗毗荼人群中具有美观外形和非正畸正常咬合的临床牙冠的近远中倾斜度和唇舌向倾斜度。
研究了40副来自达罗毗荼样本（21.5岁）的牙模，其尖牙和磨牙关系为I类；上颌与下颌关系正常；牙弓排列整齐；无牙齿异常、修复或磨耗；无既往正畸治疗史，且生长正常。使用定制的转矩角度测量装置测量牙冠倾斜度。采用学生t检验将每种牙型的算术平均值和标准差与安德鲁高加索人标准值进行比较。
研究组上下前牙的牙冠倾斜度（近中倾斜）在统计学上显著降低，唇向牙冠转矩增加。下前牙表现为远中牙冠倾斜，而后牙则明显向近中倾斜更多。所有后牙的舌向牙冠转矩均增加。
在使用直丝弓矫治器时，建议对达罗毗荼人进行转矩和角度调整，以实现精细调整并易于保持咬合。
