- 學位論文
以纖維強化修補壓克力樹脂暫用固定局部義齒的折斷負荷
Fracture load of fiber-reinforced repaired acrylic resin provisional fixed partial denture
摘要
臨床上為評估補綴計劃的可行性，常需製作長徑距或需長時裝戴的暫時固定局部義齒，傳統PMMA樹脂製作的暫時固定假牙雖然易於襯墊、修改，但因強度不足，承受咀嚼壓力下常會發生斷裂。利用樹脂或鐵絲修補並不能有效地加強斷裂暫時固定補綴物的強度，但有學者做初步研究發現實驗用玻璃纖維能顯著地強化暫時補綴物對斷裂的抵抗力。本研究旨在評估利用各式纖維強化物修補後，壓克力暫用贗復體的折斷負荷(fracture load)與斷裂形式，並探討纖維種類、表面處理方式與樣本折斷強度、斷裂形式之相互關係。 本實驗在metal jig上製作50個PMMA樹脂下顎後牙區四單位牙橋樣本，將標準化樣本於兩橋體間切斷後均分成五組，各組分別以樹脂或玻璃纖維及聚乙烯纖維強化、修復。利用萬能材料試驗機上一直徑6公釐的鋼球施壓於臼齒橋體中央窩處，測試樣本折斷負荷，並分析紀錄樣本斷裂形式、利用掃描式電子顯微鏡觀察斷面。 結果顯示平均折斷負荷最高的是light-cured FibreKor(LC-Fb)是71.50±2.33公斤，其餘組別由大至小依序為，完整樣本(Intact control)是66.03±5.51公斤，Construct(Cs)是65.90±4.91公斤，non-light-cured FibreKor(Fb)是59.56±7.55公斤，Connect(Cn)是52.82±5.19公斤，單純用樹脂修補(PMMA resin)是49.63±6.88公斤。以one-way ANOVA統計分析發現各組平均斷裂負荷有顯著差異(P<0.0001)。Tukey method做事後檢定比較各組間差異，發現沒用纖維強化及有用纖維強化的組別間有顯著差異。LC-Fb組平均折斷負荷明顯高於Fb、Cn或PMMA組(P<0.05)，但與Cs或Intact control組間統計上沒有顯著差異(P>0.05)；此外LC-Fb、Cs、Fb等組的平均折斷負荷統計上明顯較PMMA組高(P<0.05)。以斷裂形式而言，破碎斷裂大多發生在未用纖維強化的Intact control和PMMA resin組樣本；彎曲斷裂則大多發生於Cn組樣本；LC-Fb、Fb和Cs等組，樣本則大多發生部分斷裂。本實驗結果顯示纖維強化確實可提高修補後暫用贗復體的折斷負荷，使用纖維加強、修補暫時固定局部義齒可以減少再斷裂的機會。而纖維表面處理方式是影響強化效果的主要因素。
並列摘要
To evaluate the feasibility of prosthodontic treatment plan in the clinic, fabricating long-span provisional fixed partial dentures for a period of time is usually required. And, provisional fixed partial dentures of traditional PMMA resin are, easy to be relined or modified, but, lacking of strength, they often get fractured from maticatory stresses. Although it has been shown that incorporation of metal wire and/or resin is not effective to reinforce the strength of fractured provisional FPD, some preliminary studies indicated the effect of experimental glass fiber reinforcement on the fracture resistance of provisional restoration was significant. Therefore, the purpose of this study is to evaluate the fracture load and fracture pattern of repaired acrylic resin provisional restoration, which had been reinforced with various kind of fiber reinforcement. Besides, it also aims to investigate the relationships between type/surface treatment of fibers and fracture pattern/fracture strength of samples. In the experiment, first, 50 standardized 4-unit bridge samples (n=50) over mandibular posterior region were fabricated with PMMA resin from a metal jig. Next, they were divided into 5 groups evenly. Then, each group was repaired with resin or glass fiber/ polyethylene fibers. After that, the load was applied to the fixed partial dentures by a 6mm steel ball mounted in a universal testing machine placed in the middle fossa of the pontic molar tooth. Finally the fracture load and fracture pattern of all specimens were recorded and the fracture surfaces of selective samples were observed under SEM. The results revealed that specimens reinforced with light-cured FibreKor (71.5±2.33 Kg) showed the highest fracture load, followed by Construct (65.9±4.90 Kg), non-light-cured FibreKor (59.56±7.55Kg), Connect (52.8±5.19 Kg), and the specimens without fiber exhibited the lowest values (49.63±6.88 Kg). In addition, One-way ANOVA revealed significant differences between the means of the fracture load values. And the Tukey post hoc statistical analysis revealed significant differences between fiber-reinforced groups and non fiber-reinforced groups: the fracture load of light-cured FibreKor reinforced group is significant higher than those of non-light-cure FibreKor reinforced group and Connect group (P<0.05); the difference between LC FibreKor reinforced group and Construct group is not statistically significant(P>0.05). As for the forms of fracture, the majority of unreinforced specimens displayed “catastrophic” fractures; most of Connect-reinforced specimens mainly displayed “flexuous” fracture, and other fiber-reinforced specimens displayed “partial” fracture. In short, the results indicate that fiber-reinforcement indeed enhances the fracture resistance of repaired provisional fixed partial denture; using fiber to reinforce and repair provisional fixed partial denture can decrease refracture chance, and the way of surface treatment to fibers seems to be the dominate factor to influence the fracture load of a long-span repaired provisional FPD.