臺灣博碩士論文加值系統

背景：
過去的文獻對於理想牙弓的形狀，作了很多的研究，這些研究大多是利用數學方程式的圖形來表式，如拋物線，雙曲線，橢圓型，多次元方程式……，但是一直沒有一個簡便的公式能夠給臨床醫師在討論牙弓形狀時，有一個立即性的參考數字。

研究目的：

本研究旨在探討
1. 不同的性別在牙弓的大小與比例上是否有差異。
2. 不同醫師在牙弓分類上的觀測者間同意度。
3. 不同的牙弓形狀(方形，尖形，卵圓形)在大小比例上是否有差異。

研究方法：

研究對象為79位南部某醫學大學牙醫系學生，將學生的下顎模型印模後，掃描進電腦製作成圖檔，將每顆牙齒的位置換算成座標，並且定義出不同的距離變項與比例變項。

距離變項如下：(W3)：兩側犬齒尖之距離；(W4):兩側第一小臼齒頰側齒尖之距離；(W5):兩側第二小臼齒頰側齒尖之距離；(W6):兩側第一大臼齒近心頰側齒尖之距離；(W7):兩側第二大臼齒遠心頰側齒間之距離；(D3)：兩側犬齒連線，相對於正中門齒近心交接點之垂直距離；(D4)：兩側第一小臼齒頰側齒尖連線，相對於正中門齒近心交接點之垂直距離；(D5)：兩側第二小臼齒頰側齒尖連線，相對於正中門齒近心交接點之垂直距離；(D6)：兩側第一大臼齒近心頰側齒尖連線，相對於正中門齒近心交接點之垂直距離；(D7)：兩側第二大臼齒遠心頰側齒尖連線，相對於正中門齒近心交接點之垂直距離

比例變項則用距離變項相除，設定如下: W3/W7、W3/W6、W3/W5、W3/W4、W4/W7、W4/W6、W4/W5、(W3/D3) / (W7/D7)、(W3/D3) / (W6/D6)、(W3/D3) / (W5/D5)、(W3/D3) / (W4/D4)、(W4/D4)/(W7/D7)、(W4/D4) / (W6/D6)、(W4/D4) / (W5/D5)。

之後以問卷請一位矯正專科醫師、一位補綴科醫師與八位研究生醫師各自針對79個牙弓的形狀分類，以此得到10份問卷。

最後統計上則以矯正專科醫師的牙弓分類當成基準，利用ANOVA 與Receiver operating characteristic (ROC) curves進行牙弓各個距離變項與比例變項分析；再以kappa statistics 將矯正醫師的分類與其他醫師一對一分析。

結果：

在距離變項的方面，男性的牙弓普遍大於女性。男女性別在比例變項中則沒有顯著差異。針對牙弓形狀與距離和比例變項方面，牙弓形狀在距離變項中有6個變項有統計上顯著差異，在比例變項中有12個變項有統計上顯著差異。12個比例變項經過Receiver operating characteristic (ROC) curves分析，最後(W3/D3)/(W7/D7)在分辨牙弓上有最好的預測準確度。而其它醫師與矯正醫師的測量員間同意度都有「良好」以上的同意度。

結論與建議：

本實驗針對牙弓的類別，提供一簡便的方法：(W3/D3)/(W7/D7)。

臨床醫師在牙弓分類上，在討論病例時，可利用這個數值上給予一個立即性的視覺參考：數字越大的越偏向方形牙弓，數字越小的則越偏向尖形牙弓，居中的則是卵圓形牙弓。本實驗的(W3/D3)/(W7/D7)平均值 ± 標準差為4.60± 1.15。

關鍵字：牙弓形狀，比例變項，距離變項，受試者工作特徵曲線

Objective:
Many researchers have attempted to define ideal dental arch forms utilizing complex mathematical equations like parabolas, hyperbolas, and sixth power polynomials.The purpose of this study was to find a simple way to differentiate tapered, ovoid, and square arch forms.

Material and Methods:

Seventy-nine mandibular arch casts were obtained from students at Kaohsiung Medical University. Every tooth in each cast was computer digitalized into x and y coordinates. One orthodontist, one prosthodontist and eight post graduate students were invited to classify these 79 casts according to arch types (tapered, ovoid and square) based on their clinical experience. Ten distance variables ( 5 arch width and 5 arch depth variables) and fourteen ratio variables were tested. The 5 arch width variables included the distance between cusp tips of bilateral canines (W3), between buccal cusp tips of bilateral first premolars (W4), between buccal cusp tips of bilateral second premolars (W5), between mesio-buccal cusp tips of bilateral first molars (W6) and between disto-buccal cusp tips of bilateral second molars (W7).

The 5 distance variables of arch depth included the distances from the central incisors’ incisal edge to the line joining the cusp tips of bilateral canines (D3), to the line joining the buccal cusp tips of bilateral first premolars (D4), to the line joining the buccal cusp tips of second premolars (D5), to the line joining the mesio-buccal cusps of the first molars (D6), and to the line joining the disto-buccal cusps of the second molars (D7).

The 14 ratio variables included : W3/W7, W3/W6, W3/W5, W3/W4, W4/W7, W4/W6, W4/W5, (W3/D3)/(W7/D7), (W3/D3)/(W6/D6), (W3/D3)/(W5/D5), (W3/D3)/(W4/D4), (W4/D4)/(W7/D7), (W4/D4)/(W6/D6) and (W4/D4)/(W5/D5).

The orthodontist’s classification was utilized as the basis for the correlation of variables.

ANOVA was used to statistically establish significance between the 3 arch forms and the distance and ratio variables. Ratio variables that were statistically significant were selected for Receiver operating characteristic (ROC) curves analysis. Receiver operating characteristic (ROC) curves were computed using the SPSS statistical program to calculate the area under curve (AUC) for each chosen ratio variable. Larger AUC indicated better classification ability. AUC >0.8 indicate good classifying ablility.

We used kappa statistic to calculate the strength of inter-observer agreement of arch form classification between the orthodontist and the other dentists. (kappa value : <0.4:marginal, 0.4~0.75 : good, >0.75 : excellent)

Result:

The distance variables among males were longer than females, except D3. The results showed that there was no significant gender difference in ratio variables. However, there were significant differences among 6 distance variables (W3, W4, W5, W7, D3, D4) with arch form classifications when analyzed with ANOVA (p<0.05). There were significant differences among 12 ratio variables (all ratio variables except W4/W6 and W4/W5) with arch form classification with ANOVA (p<0.05). After analyzing the 12 statistically significant ratio variables by Receiver operating characteristic (ROC) curves, (W3/D3)/ (W7/D7) had the best area under curve in determining arch form.
Every dentist demonstrated “good” strength of agreement in the kappa classification with the rthodontists (κ>0.4) .

Conclusion:

The ratio variable (W3/D3)/ (W7/D7) provided the best results in determining arch form. The Mean ± SD was 4.60± 1.15.

Keywords: arch form, distance variables, ratio variables, Receiver operating characteristic (ROC) curves

中文摘要 I
Abstract III

第一章 前言 1
第一節 研究背景 1
第二節 研究目的 3

第二章 文獻回顧 4
第一節 牙弓的發育 4
第二節 牙弓形狀的研究~楔子 6
第三節 二十世紀早期的研究 7
第四節 懸垂線概念的牙弓形狀 9
第五節 多項式概念的牙弓形狀 10
第六節 拋物線、橢圓形以及雙曲線概念的牙弓形狀 12
第七節 Beta function 14


第三章 材料與方法 16
第一節 研究對象 16
第二節 研究方法 19
第三節 資料統計分析方法 25
第四節 受試者工作特徵曲線Receiver operating characteristic (ROC) curves 27
第五節 Intraclass Correlation Coefficient31

第四章 結果 32
第一節 牙弓分類基本資料 32
第二節 距離變項與比例變項基本資料 33
第三節 距離變項與比例變項與性別的關係 34
第四節 距離變項與比例變項與牙弓形狀的關係 36
第五節 受試者工作特徵曲線Receiver Operating Characteristic ( ROC ) curve 38
第六節 各醫師間分類之同意度 40

第五章 討論 41
第一節 距離變項 41
第二節 方形、卵圓形、錐狀牙弓 42
第三節 以ROC curve分析牙弓形狀 46
第四節 醫師之間的同意度 kappa value 51

第六章 結論 52
第一節 結論 52
第二節 建議 54
參考文獻 55
附表 58
附圖 70

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