Dental anomalies of number in orthodontic patients

AbstractIntroductionThe prevalence and distribution of dental anomalies of number vary according to the population studied.ObjectiveTo determine the prevalence of dental anomalies of number by assessing the frequency of hypodontia and hyperdontia regarding gender, the region of the maxila or mandible and the most affected teeth.MethodThe panoramic radiographs of 1054 patients, aged 5 to 30 years, from a private diagnostic imaging clinic were evaluated. Gender, age, presence or absence of abnormality, affected teeth and region were compared. Chi-square statistical tests and Pearson Test Binominal for two proportions were carried out.ResultThe prevalence of hypodontia was 4.9% and it was more frequent in the maxilla. There were no significant differences between the left and right side of the maxila or genders. The most frequently missing teeth were the maxillary lateral incisors and mandibular second premolar. The prevalence of hyperdontia was 4.0%. There were no significant differences between genders, right or left side of the maxila or mandible. The regions most frequently affected were distal to the third molars and between mandibular premolars.ConclusionThe prevalence of hypodontia was 4.9% and it was more frequent in the maxilla. The prevalence of hyperdontia was 4%. No significant differences between genders and the maxillary or mandibular region were found.

【摘要】牙数目异常的患病率与分布特征因研究人群的不同而存在差异。
目的 本研究旨在通过评估先天缺牙（hypodontia）与多生牙（hyperdontia）的发生频率，结合性别、上下颌区域及好发牙齿情况，明确牙数目异常的患病率。
方法 本研究对某私立影像诊断诊所的1054名5~30岁患者的全景曲面体层片（panoramic radiographs）进行回顾性分析。对患者的性别、年龄、牙数目异常发生情况、受累牙齿及受累区域进行对比，并采用卡方检验（chi-square test）与两比例Pearson二项检验开展统计学分析。
结果 先天缺牙的患病率为4.9%，且以上颌受累更为多见。上颌左右侧及性别间未发现显著统计学差异。最常缺失的牙齿为上颌侧切牙与下颌第二前磨牙。多生牙的患病率为4.0%，性别、上下颌左右侧均未发现显著统计学差异。好发区域为第三磨牙远中部位及下颌前磨牙之间。
结论 本研究显示先天缺牙患病率为4.9%，以上颌受累更为常见；多生牙患病率为4%，性别、上下颌区域间均未发现显著统计学差异。