Objective: Experimental measurements on various restoration configurations have shown that restored teeth deform under the influence of polymerization shrinkage, but actual residual stresses could not be determined. The purpose of this study was to calculate and validate shrinkage stresses associated with the reported tooth deformations.
Methods: Three different restoration configurations were applied in a finite element model of a molar. The composite properties were based on experimentally determined composite behavior during polymerization. The occlusal deformation pattern and the residual stress states of the tooth, restoration, and tooth-restoration interface were calculated using a polymerization model based on the post-gel shrinkage concept. Reported strain gauge measurements and occlusal deformation patterns were used for validation.
Results: The shrinkage stresses depended on the configuration and size of the restorations. The tooth's resistance against polymerization shrinkage diminished with loss of dental hard tissue. Larger restorations resulted in lower stress levels in the restoration and tooth-restoration interface, but increased stresses in the tooth. The maximum stress values found for different configurations were not decisively different.
Significance: The validated model indicated that shrinkage stress cannot be based on composite properties or restoration configuration alone, but has to be approached as a distributed pattern that depends on the location and on the properties of tooth and restoration, geometry, constraints, and restoration procedures. Tooth deformation was indicative of stresses in the tooth rather than in the restoration or across the tooth-restoration interface.
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http://dx.doi.org/10.1016/j.dental.2003.05.007 | DOI Listing |
Background: Dental caries is one of the most common non-communicable diseases in humans. Various interventions are available for the management, of which microinvasive techniques such as infiltration, sealants, glass ionomers, are novel and convenient. The purpose of this systematic review and meta-analysis was to compare microinvasive techniques with noninvasive or invasive treatment modalities in terms of effectiveness in halting interproximal caries lesion progression radiographically assessed.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Department of Fixed Prosthodontics - Faculty of Dentistry, Ain Shams University, Organization of African Unity, St, El-Qobba Bridge, El Weili, Cairo Governorate, Egypt.
Background: Home bleaching is a promising option for addressing discolored teeth conservatively. However, its impact on the physical and mechanical properties of indirect restorations remains unknown. This study provides comparative insights into the material responses to aesthetic treatments by assessing the effects of home bleaching agents on two hybrid ceramics: VITA ENAMIC and Grandio Blocs.
View Article and Find Full Text PDFJ Prosthodont Res
January 2025
Center of Stomatology, Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
Purpose: We aimed to analyze the influence of different designs (inlay, onlay, and crown) on stress distribution and crack propagation in an endodontically treated cracked premolar.
Methods: Three-dimensional (3D) finite element analysis (FEA) was employed to model an endodontically treated cracked premolar with three different restorations (inlay, onlay, and crown). Six types of loadings (vertical loading of 600 N; hot thermal-600 N vertical coupling loading; cold thermal-600 N vertical coupling loading; oblique loading of 200 N; hot thermal-200 N oblique coupling loading; cold thermal-200 N oblique coupling loading) were applied to simulate the hot and cold food/beverages intake.
Aust Vet J
January 2025
Owner of Advanced Vetcare, Melbourne, Victoria, Australia.
Mandibular and maxillary fractures are common in small animals and present significant challenges for repair due to the intricate anatomical features involved. This retrospective case series describes a technique for achieving rigid open mouth maxillomandibular fixation using interarch wiring while maintaining correct alignment between the upper and lower teeth with polymethylmethacrylate (PMMA) moulds of the canine teeth for treating maxillomandibular fractures in cats. The study includes a description of the postoperative outcomes and complications encountered.
View Article and Find Full Text PDFJ Foot Ankle Surg
January 2025
Department of Sports medicine, Peking University Shenzhen Hospital, Shenzhen, Guangdong Province, China. Electronic address:
Charcot-Marie-Tooth disease (CMT) is a hereditary peripheral neuropathy leading to neuromuscular impairments, muscle atrophy, and functional limitations. Currently, no specific treatment exists to restore muscle strength in patients with CMT, and the disease can be severely disabling. Surgical correction of cavus foot has been suggested as a potential intervention to alleviate pain and improve gait in selected patients.
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