Objective: Residual stresses from polymerization shrinkage in composite restorations deform a tooth. This may cause debonding, enamel crack propagation, and post-operative sensitivity. Deformation due to shrinkage has been measured previously at a few discrete points. The purpose of this study was to analyze cuspal deformation pattern of the occlusal portion of molars for various cavity types and sizes after restoration with a light-initiated composite.
Methods: Five extracted human molars were successively prepared as Class I, Class II OM, large Class II OM, and large Class II MOD. The cavities were filled with a light-curing composite using a dentin adhesive system. The occlusal portion of the unrestored cavity and the restoration were digitized with a profilometer. The digitized data of the unrestored and restored tooth were used to calculate the cuspal contour change with Cumulus software. Deformation was visualized as a color contour map.
Results: Cuspal deformation showed up in the contour map as a reduction of buccal and lingual contour perpendicular to the surface. Large Class II MODs exhibited the highest cuspal deformation, followed by large OM restorations. Cuspal deformations in Class I and small Class II OM restorations were not significantly different.
Significance: When a composite restoration was cured, the surrounding tooth deformed due to polymerization shrinkage. Cavity type and size affected how much cusps moved inward as a result of polymerization shrinkage. This study quantified and visualized the pattern of cuspal deformation.
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http://dx.doi.org/10.1016/j.dental.2003.05.008 | DOI Listing |
BMC Oral Health
November 2024
Department of Prosthodontics, School of Stomatology, Guizhou Medical University, Affiliated Stomatology Hospital of Guizhou Medical University, Guiyang, Guizhou Province, 550004, China.
Cureus
February 2024
Prosthodontics, College of Dentistry in Al Rass, Qassim University, Al Rass, SAU.
Background: The performance of an implant-supported prosthesis depends on the implant type, number, implant location, and prosthesis design which is directly associated with the distribution of the occlusal forces during mastication. The purpose of the present study is to analyze with three-dimensional (3D) finite element comparative analysis, the influence of implant location, number, and prosthesis design in the mandibular posterior region where multiple posterior teeth replacement is indicated, which in turn is associated with the longevity or Implant success rate.
Material And Methods: Mandibular posterior section, where 4 teeth are missing, based on the space available for implants and following the surgical guide instructions, a standard make four implants (1st and 2nd premolars {3.
J Mech Behav Biomed Mater
April 2024
University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands; Martini Hospital, Department of Special Dental Care, Groningen, the Netherlands.
Statement Of Problem: The existing knowledge is insufficient for comprehending the fatigue survival and fracture resistance of molars that have deep approximal direct and indirect restorations, whether with or without deep margin elevation (DME).
Purpose: The aim of this laboratory and in silico study is to investigate the fatigue survival, fracture strength, failure pattern and tooth deformation of molars restored with DME in combination with a direct or indirect restoration.
Material And Methods: This study utilized 45 extracted sound human molars, divided into three groups (n = 15).
J Esthet Restor Dent
January 2023
Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA.
Objective: The aim of this study is to assess the shrinkage-induced cuspal deformation and strength of large MOD restorations using three different short fiber-reinforced composite resins (SFRC).
Materials And Methods: Twenty-seven typodont teeth #30 (Columbia) received a standardized slot-type preparation (5-mm by 5-mm depth and bucco-palatal width). Three types of SFRCs (everX Posterior, everX Flow, and a 50/50 mixture of both materials) were used with the Optibond FL bonding system.
J Conserv Dent
July 2021
Department of Prosthodontics and Crown and Bridge, St. Joseph Dental College, Eluru, Andhra Pradesh, India.
Aim Of The Study: The purpose of the study is to evaluate the occlusal relationship of the mesiobuccal cusp of a mandibular first molar with the marginal ridge of maxillary first molar and second premolar and to analyze the effect of the above occlusal relation on different direct and indirect restorations using finite element analysis (FEA).
Methodology: Four hundred volunteers studying in a dental college were screened, of which 100 volunteers were selected for studying occlusal relationships based on the inclusion and exclusion criteria. The two most common occlusal relationships were considered for analyzing two direct (amalgam and direct composite restorations) and two indirect restorations (composite and ceramic restorations).
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