行政院國家科學委員會專題研究計畫成果報告:三級異常咬合生長發育與面罩治療之探討

黃種孩童的三級異常咬合罹患率遠高於白種人，至今仍未瞭解真正的骨骼形態變化。國 內對於三級異常咬合的基本顱顏形態研究甚少，早期少數研究進行傳統測顱術分析，但礙於 只能獲得線段與角度的變異值，因此未能提供完整的顱顏形態變化訊息。其實進一步瞭解基 本三級異常咬合顱顏形態學，對未來進行矯正治療實屬非常重要的前導性研究。因此，本研 究選擇225 位男女三級異常咬合者，來探討不同年齡間與三級異常咬合的形態變化關係，希 望利用各年齡層的橫向資料來探討與建立國人三級異常咬合顱顏生長發育的變化，以提供後 續矯正治療與相關研究的參考指標。分析方法包括統計分析、薄板仿樣分析與應變張量分析， 除探討除矯正者顱顏尺寸和形狀的變化外，亦根據主軸應變原理畫出骨骼受力矯正後的變化 走向。結果發現顱顏形態的生長變化，在男女性別上並無太大差異，彼此具有相似的整體生 長變化趨勢，但局部區域仍具有變化量與分佈位置的不同。大體而言形狀變化通常伴隨尺寸 變化而發生，此發現與一般臨床研究相符合。而在局部的生長變化上，顱底整體尺寸增加最 為顯著的是age A 與age B 之比較，主要集中在前顱底與關節點附近區域。前顱底具有逐漸向 前伸張的趨勢，而後顱底在15 歲之前以增加高度為目的，15 歲之後則尺寸變化趨於平緩。 對於中臉部生長變化，可以明顯看出MPP 點是分界線，齒槽骨區域隨年齡增加而具有鐘擺效 應，相信此生長特徵應為補償門齒咬合而產生，至於MPP 後方區域，主要以增加水平長度為 目的。下顎骨之下顎枝隨年齡增加而擴增其高度與寬度，下顎本體也繼續朝前下方伸張生長， 此結果將使三級異常咬合特徵更為明顯。生長高峰期下顎骨的生長方向有顯著的改變，這主 要是代償下顎骨在此高峰期尺寸的快速增大。應變張量分析之尺寸與形狀變化可提供局部生 長變化的位置，而主應變方向更可進一步描述骨骼生長走向，綜合上述分析指標相信可提供 更完整的顱顏形態生長變化。A relatively much higher prevalence of Class III malocclusion has been observed in patients of Asian ancestry than in Caucasians. The morphologic variability of craniofacial complex in patients with Class III malocclusion has not yet been fully determined. Not too many studies were conducted to investigate the morphologic characteristics of the craniofacial complex of Taiwanese with Class III malocclusion. Those studies that were published were mostly performed by means of cephalometric analyses. The conventional cephalometric analysis has proved to be insufficient for analysis of size and shape changes of complex anatomical forms. Lines and angles measured by traditional methods are not able to provide information about where the morphological change has occurred. Identification of the morphologic characteristics of craniofacial structures in the subjects with Class III malocclusion is important for accurate diagnosis and treatment planning in treating these patients. The purpose of this study is to evaluate normal growth in the untreated Class III Taiwanese individuals through the use of cross-sectional records. Morphometric methods (statistical F-test evaluation, thin-plate spline analysis and strain tensor analysis) were applied to evaluate shape and size changes in the craniofacial configuration of Class III malocclusion subjects at 5 different developmental stages defined by chronological age. The results of this study implied that there was a similar growth trend between different sex groups. Significant changes in sizes of cranial base were found especially for growth interval from stage A to stage B. The greatest amount of growth of the cranial base occurred at the anterior part of cranial base and the spheno-occipital synchondrosis region. Anterior cranial base tended to have horizontally forward extension. Posterior cranial base increased in vertical dimension. Size changes diminished after age of 15. MPP point appeared to be a demarcation point in the growth of nasomaxillary complex. Maxillary anterior alveolar process reshaped in a forward direction as age increased. This morphologic change in shape became greater as the stages advanced, presumably to compensate for the increasing skeletal discrepancy. The region posterior to MPP tended to increase in horizontal direction. The mandibular ramus increased in height and width. The mandibular corpus extended forward and downward. Significant mandibular growth redirection occurred during the pubertal growth spurt period, which appeared to be compensating for major increments in mandibular size at the adolescent spurt. Strain tensor analysis provided information of more specific, local changes. Principal strain directions allowed an explanatory visualization of the skeletal growth direction. Both proved to be efficient for the description and statistical evaluation of size and shape variations occurring during craniofacial growth and development