ABSTRACT
Objective@#To analyze the stress difference of alveolar bone around the abutment and alveolar ridge of edentulous of three different kinds of root-attachment-supported overdenture under different load conditions, in order to provide a reference for the choice of clinical root attachment. @*Methods @#The occlusal force of overdenture was simulated by electrical resistance strain measurement in vitro. The stress of the alveolar bone, the central part of the mandibular arch and the first molar correspond to the alveolar ridge were measured. The stress difference of 3 kinds of attachment overdenture under different loading conditions were compared and analyzed.@*Results@#Under the same loading condition, all three kinds of overdentures had a certain degree of slip of the denture (magnetic attachment denture) or rotation (3 kinds of attachment dentures). The abutment neck in different parts of the dental arch and alveolar bone, anterior free end edentulous alveolar ridge stress distribution was significantly different. @*Conclusion@# ERA attachment overdenture was the most preferable, followed by the magnetic attachment overdenture. Suitable attachment should be selected based on specific clinical cases.
ABSTRACT
Objective:To evaluate the stress distribution and displacement pattern in the restoration of Stern-ERA attachment mandible removable partial denture (RPD) with different designs through three-dimensional (3D) finite element (FE) analysis.Methods:3D-FE models were established based on human CT data and manufacturer's catalog.Vertical and 45° lingual oblique forces of 100 N were applied on the artificial teeth of the RPD.Three ERA attachment partial dentures with different bracing arms were designed,namely the basic design,rest bracing arm design and cross-arch bracing arm design.The von Mises stresses and displacements of abutment teeth and mucosa under denture base were analysed.The displacement of denture bases was examined.Results:Under the vertical and oblique loading,the maximum yon Mises stress was found at the distal shoulder on the distal abutment.The maximun displacement was observed at the buccal and distal occlusal surfaces of the distal abutment.The maximum displacement on the abutment was found to be the highest in rest bracing arm design group (14.91 μm and 63.09 μm),followed by the basic design group (9.38 μm and 50.56 μm) and the cross-arch bracing arm design group exhibited the smallest displacement (8.85 μm and 47.31 μm).Conclusion:The basic design Stern_ERA attachment for unilateral mandible distal extension defect appears to be more reasonable compared with rest arm and crossing-arch arm design from biomechanical point of view.
ABSTRACT
PURPOSE: This study was accomplished to assess the biomechanical state of different retaining methods of bar implant-overdenture. MATERIALS AND METHODS: Two 3D finite element models were designed. The first model included implant overdenture retained by Hader-clip attachment, while the second model included two extracoronal resilient attachment (ERA) studs added distally to Hader splint bar. A non-linear frictional contact type was assumed between overdentures and mucosa to represent sliding and rotational movements among different attachment components. A 200 N was applied at the molar region unilaterally and perpendicular to the occlusal plane. Additionally, the mandible was restrained at their ramus ends. The maximum equivalent stress and strain (von Mises) were recorded and analyzed at the bone-implant interface level. RESULTS: The values of von Mises stress and strain of the first model at bone-implant interface were higher than their counterparts of the second model. Stress concentration and high value of strain were recognized surrounding implant of the unloaded side in both models. CONCLUSION: There were different patterns of stress-strain distribution at bone-implant interface between the studied attachment designs. Hader bar-clip attachment showed better biomechanical behavior than adding ERA studs distal to hader bar.