Effects of pontic span and fiber reinforcement on fracture strength of multi-unit provisional fixed partial dentures

Abstract

Background/purposeClinically, PMMA resin is extensively used for fabricating provisional FPDs. However, fracture often occurs due to the unsatisfactory mechanical strength, especially within connectors of long-span provisional FPDs. The purpose of this study is to evaluate the fracture load of fiber-reinforced provisional FPDs with various pontic span lengths, and to identify the most suitable span length for fiber-reinforced long-span provisional FPDs.Materials and methodsFifty-six provisional FPDs with various pontic span lengths were fabricated. Seven samples from each group were reinforced with glass fibers. Unreinforced counterparts served as control. The samples were fixed on the abutments after thermocycling and then received a fatigue test. Subsequently, they were mechanically loaded until fracture, and the initial fracture load and fracture patterns were recorded. Statistical analysis, including two-sample t-test, one-way, two-way ANOVA, Tukey-Kramer HSD post hoc analysis and χ2 test were used to evaluate mechanical performance.ResultsThe mean fracture load of FPDs with 14 mm pontic span length is significantly higher than the other lengths. The fracture load of each reinforced group is significantly higher than each counterpart control. There is no interaction between two variables, pontic span and fiber reinforcement. With fiber reinforcement, the fracture patterns were altered from catastrophic fracture to bent or partial fracture. But, the fracture patterns were not affected by pontic span.ConclusionThe fracture load of acrylic FPDs decreases significantly when pontic span length is greater than 17 mm. Adding glass fibers into long-span provisional FPDs can significantly improve the fracture resistance and fracture patterns.

Prosthodontic Applications of Polymethyl Methacrylate (PMMA): An Update

“…To improve the properties of PMMA materials, a variety of fibers have been added and extensively characterized ( Table 6 ). Several studies [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ] have reported the improvement of various properties of fiber-reinforced PMMA. The characteristic reinforcement benefits are obtained due to the greater length of the fibers compared to the cross-sectional diameter.…”

“…Although there are a number of concerns associated with using PMMA, such as the fracture of dentures due to water sorption and poor impact and flexural strength, the ongoing research has introduced a variety of modifications to overcome and further improve its properties (such as its conductivity, water sorption, solubility, impact and flexural strengths). For example, several studies reported the improvement of PMMA materials while reinforced using a variety of fibers [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], nanoparticles [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ], and nanotubes [ 38 , 39 , 40 , 41 , 42 ]. Similarly, PMMA-based biocomposites with the addition of epoxy resins, polyamide, or butadiene styrene have been reported to improve the impact strength of PMMA [ 43 ].…”

Influence of the Physical Inclusion of ZrO2/TiO2 Nanoparticles on Physical, Mechanical, and Morphological Characteristics of PMMA-Based Interim Restorative Material

“…Several efforts have been made to improve the mechanical performance of PMMA interim restorations by adding various filler particles such as fibers [27,28], NPs [29][30][31][32][33], and nanotubes [34][35][36]. The inclusion of inorganic nanofillers into PMMA changes the characteristics of the final product based on the size, shape, type, concentration, and filler to matrix interaction [33].…”

Interim Restorations in Fixed Prosthodontics: A literature review

“…Additionally, fractures are caused by water sorption, solubility, and aging because absorbed water acts as a plasticizer and decreases the strength of the resins. (3,28,29) Stress concentration during parafunctional or functional activities also leads to fractures particularly, in a connector of long-span transitional restorations. Moreover, minimum tooth reduction results in a thin restoration that is mostly exposed to fracture.…”

“…(3) The most common repair materials used are autopolymerized acrylic resins that have the ability to rebuild the defects, providing easy and fast manipulation but, the use of these properties than other fibers. (29,37) The most common fibers used in Commonly used materials for CAD/CAM interim fixed restorations include CAD/CAM polymethyl methacrylate (Figure 6) and composite resins . (6) Figure 6.…”