ABSTRACT
This study was done to determine the role of cement liner as a reducing factor to the fluid movement in order to prevent tooth hypersensitivity according to the hydrodynamic theory during cementation of crowns. A total of fourty freshly extracted intact lower molar were selected for this study. After conventional tooth preparation the teeth were sub-divided into four equal groups to identify the role of cement liner in preventing the penetration of used cement into the dentinal tubules. Scanning electron microscopic study proved the efficiency of glass ionomer liner on preventing cement penetration into the dentinal tubules.
Subject(s)
Composite Resins/pharmacology , Dentin Sensitivity/prevention & control , Phosphates/pharmacology , Zinc Compounds/pharmacology , Crowns , Dental Cavity Lining , Dentin/drug effects , Dentin/ultrastructure , Dentin Sensitivity/chemically induced , Glass Ionomer Cements/pharmacology , Humans , In Vitro Techniques , Mandible , Microscopy, Electron, Scanning , Molar/ultrastructure , Tooth Permeability/drug effectsABSTRACT
Repairing porcelain fractures has become of interest to the dentist. The intra oral fracture of metal-ceramic restorations may be due to inadequate metal support, excessive porcelain thickness, technical flaws, and occlusal forces. Various techniques for intra oral porcelain repair have been suggested. The resin-porcelain junction has been in question since the advent of the porcelain veneer for cast metal restorations. To enhance this, several intermediary products and techniques have been developed to increase the chemical bond between the fractured porcelain and the repair materials. Clinical procedures for porcelain repair has required roughening of porcelain surface with a rotary abrasives, application of silane followed by composite to replace the contour of the restoration (2, 13, 14). Laboratory data suggested that the strong bond of the repair materials was developed.
Subject(s)
Dental Leakage/microbiology , Dental Porcelain , Denture Repair/methods , Denture, Partial/microbiology , Metal Ceramic Alloys , Mouth/microbiology , Bacteria, Aerobic/isolation & purification , Bacteria, Anaerobic/isolation & purification , Dental Casting Technique , Dental Leakage/prevention & control , Dental Restoration Failure , Dentin-Bonding Agents , Humans , In Vitro Techniques , Resin CementsABSTRACT
Fixed restorations should satisfy certain biologic requirements and they must not be injurious to the surrounding living tissues as pulp, periodontal ligament, alveolar bone and gingiva. It is best to terminate preparations above the gingival margin but for retention and esthetics considerations the margins of the fixed restorations could be placed subgingivally. In recent years, the biologic effects of dental restorative materials on the gingiva and periodontal tissues have been better appreciated. A rough surface restoration attracts and retains bacterial plaque and irritates the surrounding soft tissues which is injurious to the living supporting structure of the abutments.
