Smith C P, Al-Awadhi E A, Garvey M T
Dublin Dental University Hospital, Ireland.
Eur Arch Paediatr Dent. 2012 Jun;13(3):152-6. doi: 10.1007/BF03262863.
Failure of eruption of mandibular permanent molars occurs infrequently but is a difficult clinical problem. It can be due to local or systemic factors or failure of the eruption process. Primary failure of eruption (PFE) is a rare condition that can result in severe posterior open bite, requires complex treatment strategies and has unfavourable outcomes. Mechanical failure of eruption (MFE) is more unusual but can respond positively to treatment. Differentiating between the two is crucial in making the correct diagnosis and managing the case successfully.
A 10-year-old girl presented with a partially erupted mandibular right first permanent molar, 46. She had no relevant medical or dental history and no family history of tooth eruption failure.
46 was monitored for 6 months to allow spontaneous eruption. Local and systemic factors were eliminated. Progress radiographs and longitudinal clinical data were collected. Attempted eruption of 46 was completed by surgical luxation and elevation by orthodontic force.
FOLLOW-UP: Surgical luxation and elevation of 46 was repeated with the removal of the mandibular right second permanent molar, 47, which was mechanically obstructing the eruption of 46. With continued orthodontic force the tooth was righted up and brought into occlusion with no complication of ankylosis. The mandibular right third molar continues to erupt and migrate mesially. The patient now exhibits a bilateral functioning posterior bite three years after the treatment was commenced.
Through a combination of sequential monitoring with treatment including surgical luxation and orthodontic force, a therapeutic diagnosis of MFE was made. The appropriate treatment was carried out and the tooth erupted into occlusion.
下颌恒牙萌出失败虽不常见，但却是一个棘手的临床问题。其原因可能是局部或全身因素，也可能是萌出过程出现故障。原发性萌出失败（PFE）是一种罕见病症，可导致严重的后牙开合，需要复杂的治疗策略且预后不佳。机械性萌出失败（MFE）则更为少见，但对治疗可能有积极反应。区分这两者对于正确诊断和成功处理病例至关重要。
一名10岁女孩，下颌右侧第一恒磨牙46部分萌出。她无相关病史及牙病史，也无牙齿萌出失败的家族史。
对46进行了6个月的监测，以期待其自然萌出。排除了局部和全身因素。收集了进展性X线片和纵向临床数据。通过手术松动并施加正畸力完成了46的萌出尝试。
对46再次进行手术松动并施加正畸力，同时拔除了机械性阻碍46萌出的下颌右侧第二恒磨牙47。持续施加正畸力使牙齿扶正并进入咬合，未出现粘连并发症。下颌右侧第三磨牙继续萌出并向近中移动。治疗开始三年后，患者目前双侧后牙咬合功能正常。
通过序贯监测并结合包括手术松动和正畸力在内的治疗，做出了MFE的治疗性诊断。实施了恰当的治疗，牙齿萌出并进入咬合。
