ABSTRACT
This article discusses the fracture resistance of 4 post and core systems including a combined obturator/post system before and after fatigue loading. The obturator/post demonstrated the highest fracture resistance values. The use of a combined obturator/post with a single resin endodontic sealer/luting cement seems promising.
Subject(s)
Dental Materials , Post and Core Technique , Tooth Fractures , Tooth, Nonvital , Humans , Acid Etching, Dental , Composite Resins/chemistry , Crowns , Dental Materials/chemistry , Dental Prosthesis Design , Dental Stress Analysis/instrumentation , Dentin-Bonding Agents/chemistry , Gold Alloys/chemistry , Materials Testing , Post and Core Technique/instrumentation , Resin Cements/chemistry , Root Canal Filling Materials/chemistry , Root Canal Preparation , Stress, Mechanical , Tooth Fractures/physiopathology , Tooth, Nonvital/physiopathology , Zinc Phosphate Cement/chemistryABSTRACT
The management of trauma to the commissures has been an ongoing challenge for the medical and dental professions. Multiple surgical and prosthetic approaches have been used. Commissure splint therapy is often effective in association with surgery in reducing the effects of scar contraction that ultimately results in microstomia and reduced quality of life. This article describes methods of fabrication of the commissure splint appliance, the rationale for its modification, advantages, and disadvantages.
Subject(s)
Lip/pathology , Splints , Acrylic Resins/chemistry , Cicatrix/prevention & control , Contracture/prevention & control , Equipment Design , Humans , Lip/injuries , Lip/surgery , Orthodontic Wires , Stainless Steel/chemistry , Surface PropertiesABSTRACT
PURPOSE: This study evaluated the influence on dimensional accuracy of dental casts made with different types of trays and impression materials and poured at different and multiple times. MATERIALS AND METHODS: Two types of stock trays (plastic stock tray, perforated metal stock tray) and 4 types of custom tray materials (autopolymerizing acrylic resin, thermoplastic resin, and 2 types of light-polymerized acrylic resins) were used with 2 types of impression materials (addition polymerizing silicone and polyether), to make impressions of a metal master model. Each tray and impression material was used to make 5 impressions. Casts were made by multiple pourings at 30 minutes, 6 hours, 24 hours, and 30 days after impression making. Using a measuring microscope, 12 distances were calculated based on measurements of 8 reference points. The absolute value of the difference of each measurement was calculated, as was the corresponding measurement on the master model. A Bayesian model using a simple noninformative prior was used to analyze these data. RESULTS: Statistical differences within 6 microm were found only with thermoplastic resin tray material for addition silicone, and for thermoplastic resin tray material and 1 type of light-polymerized acrylic resin for polyether. Neither stock trays nor custom trays contributed to the differences in accuracy of the casts. All deviations in casts made with silicone impression material were within a clinically acceptable range. For the polyether, distortions occurred that were clinically unacceptable. Impressions made from polyether distorted over time. Silicone impression material has dimensional stability up to 30 days. CONCLUSION: Accurate casts can be made with either stock trays or custom trays. An impression made from polyether should be poured only once and within 24 hours after impression making, because of the distortion of the material over time. Silicone impression material has better dimensional stability than polyether. .
