顏面型態影響下顎第三大臼齒萌發預後之相關性分析
The Influence of Facial Morphology on The Prognosis of Eruption on Lower Third Molars
中文摘要
第三大臼齒是齒列中發育變異最大的牙齒。目前許多研究結果均顯示影響下顎第三大臼齒萌發 預後因素為多因子性。本研究的目的在利用牙科檢查時常用的測顱放射線片與環口顎全景片，
以顱顏發育已達成熟穩定的成人永久齒列為樣本，歸納出顏面形態對下顎第三大臼齒預後的特 異性，做為研究生長發育以及牙科治療上的參考。
本研究以116 位成年男性共 232 個下顎第三大臼齒為樣本，經由測顱放射線片分析顏面型態 與環口顎全景片分析下顎第三大臼齒角度與位置來歸納出顏面形態對下顎第三大臼齒萌發預後 的特異性。
研究結果顯示下顎第三大臼齒角度與位置無左右側差異。下顎第三大臼齒正常萌發與阻生者之 顏面型態差異主要在上下顎骨。正常萌發者較阻生者有較長而前突的上下顎，較小的下顎骨體 下顎枝交角與較前傾的下顎中切齒角度。
英文摘要
Prediction of 3rd molar (M3) prognosis in position and eruption are important clinical issues because dentists often had difficulties in making decisions as to whether mandibular M3 should be removed in orthodontic or other dental treatment. The aim of the present study was to determine radiographically the angulations and position of mandibular M3 in relation to facial morphology in male adult Taiwanese.
A total of 116 university male students with a number of 232 mandibular M3 which were completely root formatted, intact lower arch, and not received orthodontic treatment samples, Panoramic and cephalometric radiograph were taken in standardized condition. The mandibular M3 was divided into eruption and impaction groups to investigate the relationship between facial morphology and the prognosis of eruption.
There was no difference on angulations and position of mandibular M3 between right side and left side. Compared with the impacted group, the erupted group had anteriorly positioned and larger maxilla and mandible, less ramus-corpus angle and more protrusive lower incisors.
