Lakhani M Junaid, Kadri Wahab, Mehdi Hassan, Sukhia Houshang, Bano Asma, Yaqoob Sania
Department of Oral and Maxillofacial Surgery, Jinnah Medical and Dental College, Karachi, Pakistan.
J Ayub Med Coll Abbottabad. 2011 Jan-Mar;23(1):63-5.
Impaction of the 3rd molar is a high incident problem occurring in up to 73% of young adults in Europe. Appropriate follow-up routines and optimal timing for surgical removal of the 3rd molars can be established in patients judged to be at increased risk of impaction. The purpose of this study was to identify risk factors for mandibular 3rd molar impaction in adolescent orthodontic patients and to establish anterior arch crowding as a predictive model for mandibular 3rd molar impaction.
Pre-treatment Orthopantomogram (OPG) of 158 orthodontic patients with the evidence of anterior arch crowding on pre-treatment study models were evaluated for mandibular third molar position.
Out of 158 patients, 45 were male and 113 were female. Ninety-seven (61%) of the patients showed anterior arch crowding with a space discrepancy of 5-10 mm calculated on the pretreatment study models. Fifty-seven patients showed 107 third molar impactions. Anterior arch crowding in these patients was ranging from 7-10 mm. Out of 107 impacted third molars 73 were Mesioangular 14 were Distoangular 6 were Vertical and 14 were Horizontal.
If the arch size is smaller as compared to the tooth size the evidence of lack of space would be there in anterior segment as crowding and in posterior segment as 3rd molar impaction.
第三磨牙阻生是一个高发问题,在欧洲高达73%的年轻人中都会出现。对于被判定为阻生风险增加的患者,可以制定适当的随访程序以及确定第三磨牙外科拔除的最佳时机。本研究的目的是确定青少年正畸患者下颌第三磨牙阻生的风险因素,并建立前牙弓拥挤作为下颌第三磨牙阻生的预测模型。
对158例正畸患者治疗前的曲面断层片(OPG)进行评估,这些患者在治疗前研究模型上有前牙弓拥挤的证据,以确定下颌第三磨牙的位置。
158例患者中,男性45例,女性113例。97例(61%)患者在前牙弓出现拥挤,根据治疗前研究模型计算,间隙差异为5-10mm。57例患者出现107颗第三磨牙阻生。这些患者的前牙弓拥挤范围为7-10mm。在107颗阻生第三磨牙中,近中阻生73颗,远中阻生14颗,垂直阻生6颗,水平阻生14颗。
如果牙弓尺寸小于牙齿尺寸,在前牙段会出现拥挤,表现为间隙不足,在后牙段则会出现第三磨牙阻生。