壓克力樹脂暫用補綴物臨床上常發生斷裂問題，前牙暫用固定局部義齒需要考量強度及美觀。本研究旨在測量纖維或不銹鋼線強化前牙壓克力樹脂暫用固定局部義齒的折斷負荷，並分析不同強化物種類、長度對於折斷負荷、斷裂型式的影響。將70個以PMMA樹脂製作的標準化上顎前牙四單位牙橋均分成7組(n=10)；未加強化物樣本為控制組，實驗組樣本則以不同長度(4, 15mm)的三種型式強化物(stainless steel wire, FibreKor, Construct)強化。所有樣本施予冷熱循
環(600×5℃~55℃，含浸1分鐘)後，以萬用材料測試機測試樣本初始斷裂，記錄其折斷負荷和斷裂型式，並利用電子顯微鏡觀察選擇樣本之斷面。結果顯示折斷負荷最大為15公厘不銹鋼線強化組16.98±3.45公斤，最小為控制組10.3±2.37公斤。Two-way ANOVA統計分析顯示，強化物種類、長度統計上顯著影響折斷負荷(p<.0001)及斷裂型式(p<.0001)。結論：相較於纖維強化物，15公厘不銹鋼線強化物可顯著提升樣本之折斷負荷。15公厘不銹鋼線或纖維均會改變樣本斷
裂型式，由破碎或彎曲斷裂改變為較易修補的部分斷裂。

Fracture of acrylic provisional restorations is a common clinical problem. The functional and esthetic demands of anterior provisional fixed partial dentures (FPDs) are essential. The purpose of this study was to measure the fracture load of anterior acrylic resin provisional FPDs reinforced with fibers or stainless steel wire, and to evaluate the effect of different types and lengths of reinforcements on fracture load and fracture patterns of samples. A total of 70 standardized 4-unit bridges over the maxillary anterior region were fabricated with PMMA resin. These were then divided into 7 equal groups (n=10); un-reinforced samples formed
the control group. The experiment samples were reinforced with different length (4, 15mm) of three types of reinforcements (stainless steel wire, FibreKor, Consruct ). All samples were subjected to thermocycling (600×5~55℃, 1min dwell time), following which the load was applied to samples using a universal testing machine until initial fracture. The fracture load and fracture pattern were recorded and the fracture surfaces of selective samples were observed under SEM. The results revealed that the group reinforced with 15mm stainless steel wire showed the highest fracture load 16.98±3.45kg and the control group exhibited the lowest value 10.31±2.37kg. Statistical analysis by two-way ANOVA analysis of variance showed that the type and length of the reinforced material significantly influence fracture load (p<.0001) and fracture pattern (p<.0001). We conclude that samples reinforced with 15mm stainless steel wire result in a significantly higher fracture load as compared with samples reinforced with fibers. The use of 15mm stainless steel wire and fibers can change the mode of fractures of samples from catastrophic or flexural fractures to partial ones that easily repaired.