Nielsen Signe Hauberg, Becktor Karin Binner, Kjaer Inger
Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Eur J Orthod. 2006 Dec;28(6):529-34. doi: 10.1093/ejo/cjl049. Epub 2006 Nov 13.
This study consisted of two parts: the first part describes the aetiology behind primary retention of first permanent mandibular molars by comparing the affected molar region with the contralateral region, and the second the follow-up of the retained molars. The material comprised dental pantomograms from 29 patients (17 males and 12 females; aged 6 years 2 months to 12 years 5 months) which were sent by Danish public dental clinics to the Department of Orthodontics at Copenhagen Dental School for treatment guidance (Part 1). Questionnaires were later sent to the dentists for follow-up information regarding the affected teeth (Part 2). Part 1-aetiological evaluation: From each radiograph, the number and location of the molars, maturity of individual molars, and deviations from normal morphology were recorded. The findings showed that, in an affected region, disruption of normal dental development and eruption had occurred, causing a delay in dental maturity as well as arrested eruption of the first molar. Part 2-follow-up of eruption: Completed questionnaires and radiographs were returned for 25 subjects. In 10, eruption had occurred, six after surgical removal of mucosa covering the retained first molar. In eight patients the molar had been removed while in seven the observation time from first diagnosis was too short to evaluate eruption. The results indicate that retained first permanent mandibular molars have the ability to erupt and suggest that a unilaterally retained first permanent mandibular molar may represent a temporary delay in eruption rather than permanent failure.
第一部分通过比较患侧磨牙区域与对侧区域，描述下颌第一恒磨牙原发性滞留的病因；第二部分是对滞留磨牙的随访。材料包括丹麦公共牙科诊所发送至哥本哈根牙科学院正畸科用于治疗指导的29例患者（17例男性和12例女性；年龄6岁2个月至12岁5个月）的全口曲面断层片（第一部分）。随后向牙医发送问卷，以获取有关患牙的随访信息（第二部分）。第一部分——病因学评估：从每张X光片中记录磨牙的数量和位置、各个磨牙的成熟度以及与正常形态的偏差。研究结果表明，在患侧区域，正常牙齿发育和萌出受到干扰。导致牙齿成熟延迟以及第一磨牙萌出受阻。第二部分——萌出随访：25名受试者返回了完整的问卷和X光片。其中10例已经萌出，6例是在手术切除覆盖滞留第一磨牙的黏膜后萌出。8例患者的磨牙已被拔除，7例患者从首次诊断开始的观察时间过短，无法评估萌出情况。结果表明，下颌第一恒磨牙有萌出的能力，并提示单侧滞留的下颌第一恒磨牙可能代表萌出的暂时延迟而非永久性失败。
