| 摘要: | 在講求快速的時代，數位化牙科進展快速，導致市面上CAD/CAM用瓷塊種類越來越多，當牙醫師或牙技師面臨眾多瓷塊的選擇時，同種材料的不同厚度，所呈現的顏色數據會不一樣，要如何依照牙醫師備牙的空間，去選擇最終修復物所需要用的瓷塊顏色。
本研究利用一數位影像比色方式，測試兩種常用於前牙美觀區的玻璃陶瓷瓷塊：Vita Mark II和Ivoclar E.max CAD，分別製作五種厚度（0.5mm、0.75mm、1.0mm、1.25mm、1.5mm）的試片，試片大小皆是10*10(mm)，每種瓷塊有三種顏色（A1、A2、A3），不同厚度試片分別有3個，總計90片試片。測量不同試片厚度所呈現的CIELab值，每組試片都會重複測量五次，將所有數據（L*、a*、b＊值）進行皮爾生相關係數（ Pearson's correlation coefficient）統計分析，且將不同厚度間（0.5mm和0.75mm、0.75mm和1.0mm..以此類推）的顏色數值進行t-檢定。
研究結果顯示，瓷塊厚度和顏色數據L*、a*、b*值有高度的線性關係（R2>0.95），且不同厚度間的顏色數值呈現顯著差異（t-檢定,p<0.05）。這代表我們能夠根據牙醫師備牙的空間（也就是修復物瓷塊的厚度）和欲做的牙齒修復物顏色數值，推測要選擇哪種瓷塊的顏色，會最接近最終修復物的顏色，本研究提供了一個能花較少時間來後製顏色達到最終結果的方式，當然在牙科臨床複雜的環境上應用，仍需要更近一步的研究。
With rapid advancements in digital dentistry, the diversity of CAD/CAM ceramics has seen equally explosive growth. When this fact is combined with a selection of predetermined shades such as A1, A2, and A3, the challenge for the dental technician is to correctly balance the elements in this multifactorial environment.
This study utilized a digital shade-matching method to test two CAD/CAM ceramics commonly used in the anterior region: Mark II (VITA) and e.max CAD (Ivoclar Vivadent). The specimens were 10 mm by 10 mm in length and width, and had five different thicknesses (0.5 mm, 0.75 mm, 1.0 mm, 1.25 mm, 1.5 mm) with varying sample sizes of 3 . Three different shades of blocks were used (A1, A2, and A3) for a total sample size of 90. Each calculation was repeated five times, and the L*, a*, b* values of different thicknesses were statistically analyzed with Student T-test and Pearson’s correlation coefficient.
The results showed significant correlation between material thickness and LAB color values (R2>0.95), and also significant color difference in pairwise comparison of thicknesses (T-test, p < 0.05). Through quantitative analysis, the dental technician is able to make a calculated selection of material shade based on the clearance prepared by the dentist, and the desired LAB value in the final restoration. This method provides a reliable procedure in choosing the optimal base-color for the dental technician to begin the staining process. |
