Reinforcement in removable prosthodontics: a literature review

Abstract

Removable prosthodontics are often associated with mechanical troubles in daily use, such as fracture or deformation. These troubles render prostheses unusable and reduce wearers' QOL. Various reinforcements are used to prevent such problems, but consensus on reinforcement has not been reached. This review aimed to summarise the effects of reinforcement and to propose favourable reinforcement based on material, design and position in the prostheses. Initially, 139 articles were selected by electronic and manual searches. After exclusion of 99 articles based on the exclusion criteria, 40 articles were finally included in the review. Electronic searches were performed for articles published from 2005 to 2015 in PubMed, EMBASE, MEDLINE and Cochrane Library, and manual searches were performed in 10 journals relevant to the topic of removable prosthodontics. For in vitro studies, certain dental alloys and fibres were mainly used. Their forms were different, including complicated forms in dental alloys and various forms in fibres. The materials were examined for mechanical properties like fracture strength, flexural strength and elastic modulus and compared with one another or without reinforcement. There were a few clinical studies and one longitudinal study. Cast metal reinforcement seemed to be most favourable in terms of fracture toughness and stiffness. The most favourable forms differed depending on the prostheses, but placement around thin and deformable areas was effective. However, randomised or longitudinal clinical reports and comparative clinical studies on the use of reinforcement were still lacking and such studies are necessary in the future.

Overdenture Prostheses with Metal Copings: A Retrospective Analysis of Survival and Prosthodontic Complications

“…A recent literature review on overdenture reinforcement concluded that cast metal reinforcement was most effective in improving the mechanical properties of the prostheses, for both strength and rigidity. The reinforcement should be placed around the deformable and stress‐concentrating areas such as the occlusal surface of the copings/roots in overdenture prostheses to reduce the incidence of fracture . However, the aim of reinforcement is not solely to prevent denture base fracture, but also to enhance functional rigidity for occlusal stability, and to distribute the masticatory load to the underlying denture‐supporting areas.…”

“…Dong et al observed that the greatest strain exists beneath the overdenture surface close to the top of each coping . Clinical studies have recommended overdenture reinforcements to improve the mechanical properties of prostheses . Despite rapid development in overdenture attachments and implant‐supported overdentures, overdentures with metal copings remain a viable and usable modality in dental practice.…”

“…42 Clinical studies have recommended overdenture reinforcements to improve the mechanical properties of prostheses. [43][44][45] Despite rapid development in overdenture attachments 46 and implantsupported overdentures, [47][48][49][50] overdentures with metal copings remain a viable and usable modality in dental practice. There is limited clinical follow-up data of the complications associated with overdentures and abutment teeth restored with metal copings, including post-procedural and prosthetic problems.…”

Mechanical strength evaluation of poly(methyl methacrylate) reinforced with long glass, carbon and aramid fibers

“…The first attempts to reinforce acrylic plates of removable dentures consisted in the introduction of steel screws to dentures to prevent cracking, which only resulted in complicated repair thereof [3,[6][7][8]. The use of glass fibers to reinforce resins opened new possibilities of acrylic compound reinforcement [9].…”

Biological and technical complications in root cap–retained overdentures after 3–15 years in situ: a retrospective clinical study

“…It has been shown that RODs require extensive maintenance to prevent them from technical (e.g. chipping fractures or loss of retention) [19,20] and/or biological (e.g. recurrent caries or periodontal disease) complications [21,22].…”