An evaluation of bond strengths of denture repair resins by a torsional method

Abstract

Ab stractChemical cure resin materia.ls are generally used in the repair of dentures. Different repair resins used may yield different results. The bond strength of three autopolymerizing resins were evaluated using a torsional test method. The results showed that Palapress and Caulk resins had a higher repair strength than Rapid Repair resin .Key words: Denture repair resins, bond strength, torsion tests evaluation.(Received for publication March 1995. Revised June 1995. Accepted July 1995 Int roductionAlthough resins for denture repairs are not as extensively studied as adhesives to dentine, porcelain or enamel, the importance of denture repairs cannot be underestimated. Huggett et al. 1 cited that nearly three-quarters of a million dentures were repaired each year in England and Wales at a cost of £4 .7 million (at 1987 price) to the National Health Service (UK) and an estimated similar amount is spent by patients privately. Most of these repairs are due to failure of polymethylmethacrylate (PMMA) denture bases.Smith 2 noted that denture failure depends on the shape, conditions of loading, inherent residual stresses and mechanical properties of the denture base. Farmer 3 listed various clinical factors such as improperly contoured mandibular occlusal plane, high frenal attachment, incorrect occlusal schemes, heavy occlusal forces, poor adaptation of the denture base to the residual alveolar ridge and denture base thickness as primary causes of denture fractures. Vallittu et al. 4 noted that the highest incidence of denture fractures occurred between 16-36 months after being in service.The clinician must often decide whether to repair or replace the broken denture . To minimize inconvenience to the patient and save costs in the reconstruction of the dentures, quick and reliable denture repairs are often necessary. Success depends on correcting the offending clinical cause and a strong repair junction. Confidence in the repair rests on the repair resin. There is, therefore, a need to fully characterize the bond strength of the denture repair resins available in the market.The purpose of the present study was to use the torsional test proposed by Stewart et al. 5 to assess the relative merits of denture repair resins. It seeks to compare the shear bond strength of three commercially available acrylic resin denture repair materials in vitro.A torsional test was chosen as the stress exerted on the specimen has a significant shear component and is, therefore, closer to the clinical situation. The torsion specimen also has a uniform state of stress at any point on the specimen surface and this state of stress is less dependent on parallelism and specimen geometry than for diametral or three-point bending tests.

Stress analysis of a complete maxillary denture under various drop impact conditions: a 3D finite element study

“…The shear components are observed to remain in 50 MPa range. In various studies, it is indicated that the debonding stresses at the tooth -denture interface are at the orders of 10-40 MPa in quasi-static environment in shear (in contact local tangent plane) (Thean et al 1996;Thean et al 1998;Mian et al 2013), and 27-69 MPa in tensile (normal to interface) directions (Amin 2002;Alsiyabi et al 2004;Amarnath et al 2011). These values indicated are much lower than the ones calculated here; however, it should be noted that the tests referenced therein are conducted in quasi-static conditions: Under such conditions, PMMA is much softer and yields more easily compared with its high-strain-rate behavior.…”

Factors Affecting the Strength of Denture Repairs

“…According to Beyli and von Fraunhofer, 57 the use of a maximum of 3-mm gap size decreased the degree of polymerization contraction and reduced any color difference between the denture base and repair material. In addition, if the interface is wider than 3 mm, pure cohesive fracture might occur instead of mixed fracture; 22 however, this behavior was not observed in a study by Rached et al,24 who showed that the repair methods exhibited a low incidence of purely adhesive rather than cohesive failures.…”

“…The torsion specimen also has a uniform state of stress at any point on the specimen surface, and this state of stress is less dependent on parallelism and specimen shape than in the three-point bending test. 22 Controversies relating to the effect of surface treatment of the acrylic resin have arisen as a result of research employing different test methods (Table 1). Hence, the standardization of test methods and the conversion of results according to International Unit System for denture repairs studies are required.…”

“…The choice of denture base resin and repair material combination may also influence the final strength of denture repair. 3,9,[17][18][19][20][21][22][23][24][25] This article reviews some of the current literature with regard to the most important factors that may influence the strength of acrylic denture repairs.…”

Comparison of metal wire reinforcement and glass fiber reinforcement in repaired maxillary complete denture

“…19-31 특히, 레진 의치상 수리에 주로 사용되는 자가중합레진의 강도는 열중합레진의 18-81%에 불과하다는 연구결과가 보고되었기 때문에, [20][21][22][23][24][25][26][27] 추가적으로 금속이나 섬유(fiber)와 같은 보강재가 사용되어 왔다. 금속보강재는 비교적 술식이 간단하고 저렴하기 때문에 의 치상 강화에 널리 사용된다.…”