二級異常咬合合併深咬之齒顎顏面形態測量學分析

研究背景：過深之垂直覆咬是臨床上常會遇到的垂直方向上的異常咬合，因此安格氏二級第一分類異常咬合合併深咬患者，同時存在水平與垂直方向的問題，增加了治療的複雜度。根據過去學者的研究與經驗，前牙深咬不但對於美觀與牙周組織健康有影響，臨床治療也相當困難，即使治療成功，也常面臨到不穩定與復發的危險。研究目的：本篇研究主要是針對安格氏二級第一分類合併深咬的異常患者，並以一級咬合具正常覆咬者為對照組，對顱顏結構及齒列結構進行分析，目的在於了解國內二级第一分類異常咬合合併深咬成人之骨骼及齒顎形態特徵，以探討深咬形成原因，使治療前能就骨生性與齒生性進行比較，可做為臨床治療的參考及預後的評估。材料與方法：本研究選取80位安格氏二級第一分類異常咬合且前牙垂直覆咬過深之患者，並選取80位安格氏一級正常咬合並具有正常垂直覆咬者，兩組分別包含男女各40位，所採用之研究樣本年齡範圍為18歲以上生長發育已停止的成人，使用其側面測顱X光片圖形資料。共採用33個標記點，經描繪後利用數位板輸入電腦，傳統測顱分析共包括24個線段及24個角度項目。先計算各對應組上下顎前牙垂直覆咬深度的單變項分析（Student’s t-test），來確認安格氏二級第一分類異常咬合合併深咬組與正常咬合組之間垂直覆咬深度的確有所差異，再進行齒顎顏面形態測量項目的單變項（Student’s t-test和2-way ANOVA）及多變項分析（賀德臨氏T2檢定，Hotelling’s T2 test），其中單變項分析中的2-way ANOVA有另外針對性別因子以及咬合因子的調整，以及探討PP/MP角度次分組之間是否存在顯著差異，而多變項分析也有考量性別因子所造成的差異。結果：安格氏二級第一分類異常咬合合併深咬成人之齒顎顏面形態，與正常咬合者的確存在顯著差異，主要為成年男性的前顱底長度（S-N）與上顎骨長度（Ans-Pns）較長，成年女性的有效下顎枝高度（Ar-Go）則較短；成年女性的SNB角度較小，成年男性與成年女性ANB角度均較大，顯示下顎骨相對於上顎骨有較後縮的位置；成年女性的下顎平面（FH/MP）較大，且下顎平面相對於前顱底（SN/MP）與上顎骨（PP/MP）的傾斜程度均較大，成年男性與成年女性的下顎枝後緣傾斜程度（FH/RP）與下顎枝後緣相對於前顱底的傾斜程度（SN/RP）均顯著較大，成年男性的角點角（Ar-GoI-Me）與下角點角（N-GoI-Me）顯著較小，成年女性的上角點角（N-GoI-Ar）則顯著較小，前顏面高度（N-Me）與前下顏面高度（Ans-Me）均較大，後上顏面高度（Se-Pns）也偏大，但後顏面高度（S-Go）無明顯變短，顯示臉型有過度開展的現象；成年女性的U1-SV線段和U6-SV線段較大，上顎前牙與上顎後牙均有較前突的位置，成年男性的U1/SN角度，U1/FH角度與U1/PP角度均顯著較大，顯示上顎門齒有較外展的角度，成年男性與成年女性的L1/MP角度均較大，下顎前牙相對於上顎骨有往前往下旋轉的角度，但U6/PP角度較小，顯示上顎後牙相對於下顎骨有往後往上旋轉的角度，上下顎門齒水平覆咬（overjet）較大，上下顎門齒間角度（U1/L1）則有較小的情況，而成年男性的上下顎第一大臼齒間角度（U6/L6）則顯著較大；上顎前牙齒槽高度（U1-PP線段）與下顎前牙齒槽高度（L1-MP線段）均較大，有過度萌出的現象。此外，由賀德臨氏T2檢定得知二級第一分類合併深咬異常咬合與正常咬合組之間，線段與角度項目的確存在著顯著差異。結論：本研究發現安格氏二級第一分類合併深咬患者與正常咬合者之齒顎顏面形態，在線段及角度項目上的確有顯著差異。深咬的成因主要是來自於上顎門齒與下顎門齒的過度萌發，所以治療過程應著重於將上下顎前牙以壓入的方式並整平史必曲線來改善深咬的情形，但要注意的是二級第一分類患者具有較為開展的臉型，下顎平面角較為陡峭，在治療時要特別小心避免讓後牙更加萌出使得下顎骨平面更加開展，而造成顎骨前後關係更為惡化。關鍵詞：深咬，安格氏二級第一分類異常咬合，垂直覆咬，測顱分析

關鍵字

深咬；安格氏二級第一分類異常咬合；垂直覆咬；測顱分析

並列摘要

Background: Excessive deep overbite is frequently encountered in patients with Angle Class II division 1 malocclusion. Deep overbite not only influence esthetics and periodontal health but also increase the complexity of orthodontic treatment because it combines horizontal and vertical problems. Deep-bite has been considered widely occurred and somewhat difficult to be treated successfully. Instability and relapse of treatment result may also occur. Some cases not being treated orthodontically as well as expected could be attributed to an erroneous diagnosis of dental and skeletal components of the deep overbite. Therefore, accurate diagnosis of deep overbite components can help lessen the failure of treatment. Objective: The purpose of this study was to find out the skeletal and dental components of deep overbite in Angle Class II division 1 malocclusion patients by comparing to Angle Class I patients with normal overbite as control. Materials and Methods: Lateral cephalograms of eighty adults in Angle Class II division 1 malocclusion with deep overbite compared with eighty adult with normal occlusion. The sample of two groups included forty male and forty female. The ages of the samples were above eighteen years old. Thirty-three landmarks were indentified and digitized. Cephalometric analysis utilizing twenty-four linear and twenty-four angular measurements were undertaken. Before the undergoing of the Student’s t-test, 2-way ANOVA and multivariable analysis (Hotelling’s T2 test) of the measurements of dentofacial morphology, the depth of the vertical overbite between Class II division 1 with deep-bite malocclusion and normal occlusion were compared firstly to confirm that there is significant difference in the depth of the anterior overbite. Furthermore, the 2-way ANOVA analysis was used to discuss the significant difference among the PP/MP subgroups. Results: There is some significant difference in the dentofacial morphology between the adult of Class II division 1 with deep-bite malocclusion and the adult of normal occlusion. The adult of Angle Class II division 1 with deep-bite malocclusion have larger overbite, larger anterior cranial base length (S-N) and maxillary length (Ans-Pns) in male, shorter effective ramus height (Ar-Go) in female, smaller S-N-B angle and larger A-N-B angle, these results revealed that mandible is relatively retrusive to maxilla. Larger mandibular plane angle (FH/MP), SN/MP angle and PP/MP angle in female, larger FH/RP angle and SN/RP angle, smaller gonial angle (Ar-GoI-Me) and lower gonial angle (N-GoI-Me) in male, smaller upper gonial angle (N-GoI-Ar), larger anterior facial height (N-Me) and lower anterior facial height (Ans-Me), larger upper posterior facial height (Se-Pns) in female, but posterior facial height (S-Go) is not significant, these results showed the vertical facial type is hyperdivergent. Larger U1-SV length and U6-SV length in female, larger U1/SN, U1/FH and U1/PP angle in male, larger L1/MP angle and smaller U6/PP angle, these results presented that the upper anterior is more flare out, the upper anterior teeth and upper posterior teeth is more protrusive, the lower anterior teeth have anterior and inferior rotation, and the upper posterior teeth have posterior and superior rotation. Larger anterior overjet, smaller interincisal angle (U1/L1), larger upper anterior dentoalveolar height (U1-PP) and lower anterior dentoalveolar height (L1-MP), showed that the anterior teeth has supra-eruption condition. Besides, the results of the Hotelling’s T2 test show that linear and angular measurements are significant different between groups of Angle Class II division 1 malocclusion with deep-bite and normal occlusions. Conclusions: Our results suggested that deep-bite problems in Angle Class II division 1 patients are associated with supra-eruption of upper and lower anterior incisors. Therefore, deep-bite problems could be resolved by intruding incisors and leveling curve of Spee. Furthermore, Angle Class II division 1 deep-bite patients also presented hyperdivergent facial pattern and steep mandibular plane. Therefore, extrusion of posterior teeth or large amount increase mandibular plane angle may also worsen the anterior-posterior discrepancy. Key Words: Deep-bite, Angle Class II division 1 malocclusion, overbite, cephalometric analysis