Mishra Apurva, Pandey Ramesh K
Department of Paediatric and Preventive Dentistry, Faculty of Dental Sciences, King George Medical University, Lucknow, India.
Saudi Dent J. 2017 Apr;29(2):78-82. doi: 10.1016/j.sdentj.2017.01.004. Epub 2017 Mar 27.
To determine and compare the prevalence and pattern of agenesis of third molar and mandibular second premolar in paediatric orthodontic patients of age group 9-15 for sexual dimorphism.
The digital orthopantograph was obtained from the archive record of patients of age group 9-15 year. Radiographs of 301 patients were evaluated after taking exclusion criteria into account and were assessed for the presence/absence of third molars and mandibular second premolar. Tooth development evaluation followed the method of Demirjian et al., based on eight stages of tooth formation. The agenesis of third molar in maxilla and mandible between age groups and gender was compared using Chi-squared test.
The rate of agenesis of third molars was observed 36.8% in the present study. Twenty-four (24.3%) percentage of the study population showed agenesis of all the four third molars. The agenesis of third molars was found to be higher among males than females ( > 0.05). Prevalence of agenesis of mandibular second premolar was 4.7-5%.
Agenesis of third molars was more commonly seen in the maxilla, having male predilection. Maxillary right third molar was the most commonly missing tooth irrespective of gender.
确定并比较9至15岁儿童正畸患者中第三磨牙和下颌第二前磨牙先天性缺失的患病率及模式，以研究性别差异。
从9至15岁患者的档案记录中获取数字化全景X线片。在考虑排除标准后，对301例患者的X线片进行评估，检查第三磨牙和下颌第二前磨牙的有无情况。牙齿发育评估采用德米尔坚等人的方法，基于牙齿形成的八个阶段进行。使用卡方检验比较不同年龄组和性别的上颌和下颌第三磨牙先天性缺失情况。
在本研究中，第三磨牙先天性缺失率为36.8%。24.3%的研究人群显示四颗第三磨牙均先天性缺失。发现男性第三磨牙先天性缺失率高于女性（P>0.05）。下颌第二前磨牙先天性缺失患病率为4.7%至5%。
第三磨牙先天性缺失在上颌更为常见，且男性居多。无论性别，上颌右侧第三磨牙是最常缺失的牙齿。
