Papers by Keyword: Complete Denture

Abstract: Implant-retained overdenture has been widely applied as a solution to edentulous ageing; however, a major concern for the denture wearers is bone resorption induced by the prosthetic interaction with soft tissue and bone. Early studies have revealed that the bone resorption is associated with the disturbance to the mucosa blood flow. This study aimed to investigate the contact pressure induced by an implant-retained overdenture, compared to a conventional complete denture without implants, which implies the potential bone resorption for clinical investigation. A three-dimensional finite element model of a full jaw, including mandible bone, mucosa, and denture, was created through a reverse engineering method based on CBCT images, in which the hyperelastic behaviour of mucosa was determined by curve-fitting to the clinical measurement, for a more realistic response. It is found that the location of the bone loss differed between the implant retained and non-implant complete dentures. With the implants, the denture displaced more at posterior ends towards the mucosa bearing area, leading to higher contact pressure accounted for more severe local bone loss.

Abstract: Total dentures are made of acrylic resins and artificial teeth. Among the prevalent fracture types of the dentures, 29% was a mid-line fracture, in which 68% were observed in maxillary complete dentures and 28% in mandibular complete dentures. Due to the large number of failures recorded on the maxillary dentures, several studies were conducted to establish the causes that produce these failures but also to find solutions for their prevention. One source of information about the strength of a maxillary denture under the applied load, is represented by the establishment of the stress and strain state during the loading. Different methods have been used for investigating the strain or stress distribution during deformation of dentures. The purpose of this paper is to evaluate the stress and strain state of a maxillary denture loaded in compression until the final fracture. For this study, electrical resistance strain gage were used for evaluation the strain and stress distribution in the maxillary denture made of different acrylic resins. Based on observations from practice, the strain gages were applied on the middle line of the denture at the base of the incisors and respectively on the sides of the denture, under molars. The dentures were loaded until failure and were registered the strains in the located strain gages. Also, for each type of acrylic resin were determined separately the mechanical properties of elasticity and strength. Based on the tests conducted were determined the critical stress and strain in the areas of interest. In all the tests carried out the fracture occurred in the median area of the denture and the crack was initiated between the incisor teeth. The stress and strain field associated with the crack initiation mode showed a strong influence of geometry on the fracture strength of denture. Also the type of acrylic resin has a significant effect on the fracture strength of complete denture either by strength capacity but especially by their ability to elasticity. Based on this analysis have been established new criteria for selection of acrylic resins, not only for aesthetic reasons but also for elasticity and strength reasons.

Abstract: The digital image correlation method was used in this study to investigate heat polymerizable acrylic resin, which is the material of choice for prosthesis in edentulous patients. The aim was to analyze and determine the force-induced displacement and strain of a complete denture in the physiological force field of edentulous patients. An acrylic lower complete denture was made for the edentulous mandible, placed on the residual ridge of the macerated mandible bone, lacquered with spray, and exposed to a force of 300 N. The Digital Image Correlation system (DIC) (GOM, Braunschweig, Germany) was used to measure the strain in the complete denture, consisting of two digital cameras and the software ARAMIS (6.2.0, Braunschweig, Germany). Both fields indicated the maximum dimensional changes occurred just below the point of force incidence. The displacement field registered movements in the range from 0.165 to 0.782 mm and the principal strain field showed strain values between 1.25 and 18.94%. In vitro investigation of the dynamic behavior of the lower complete denture under load by using the optical measuring system-DIC demonstrated that the strain/displacement alterations were generally influenced by prosthesis movement toward the residual alveolar ridge.

Abstract: The complete dentures are realized by different acrylic resins and different technologies. These materials are fragile and frequently appear crack and fractures of these dentures. Also, theses materials as well as the technologies of performing these dentures are expensive. In order to avoid the ultimate failure of the complete dentures, for each case there is necessary a numerical simulation as a preliminary stage before the effective performance of the denture. In order to realize the numerical simulation of the complete denture there is necessary to know the mechanical and elastic properties of the acrylic resins. This paper presents the results of experimental investigations performed in order to determine the mechanical and elastic properties of complete denture materials. A 3D laser scanner was used for the elaboration of the geometrical model of the complete dentures. In this way, using the reverse engineering technology there was realized a very accurate geometrical model. Finite element analysis was used to estimate the durability of the same complete dentures. The calculation model was finally validated by a fatigue experimental test.