Emergency direct/indirect polyethylene-ribbon-reinforced composite resin, fixed partial denture: a case report

Gas-plasma-treated, woven polyethylene fabric to reinforce heavily filled composite resin was used to fabricate a direct/indirect fixed partial denture to esthetically replace a missing maxillary central incisor for a 12-year-old boy. The patient and his parents were interested in using a fixed prosthesis as an interim space-maintaining restoration, which would boost the patient's self-esteem. The technique used was an amalgamation of old concepts and new procedures that enable general dentists to expeditiously and inexpensively replace missing teeth. This relatively noninvasive and basically reversible procedure allows the patient to ponder the final restoration as he or she goes through growth, development, and maturation of the hard and soft tissues.     

The extracted tooth pontic--provisional replacement during bone graft and implant healing

When tooth extraction is required, a provisional restoration may be utilized as an interim prosthesis during bone graft and implant healing. The selection of provisional replacement of the anterior teeth following extraction may have a direct influence on the success of the definitive tooth replacement. This article describes a technique for using the extracted tooth or a denture tooth as an interim prosthesis during bone graft and implant healing. This method of provisionalization offers several advantages, including no adjacent tooth preparation, natural appearance, and retention of the papillae.     

Repair with a surveyed cast clasp while patient retains the partial denture

A technique is described that allows a removable partial denture with a broken clasp or a removable partial denture in which an abutment has been extracted to be restored by the reattachment of a new cast clasp component or a complete surveyed clasp assembly. The technique is applicable to most clasp designs and can include attachment to the acrylic denture base or the metal major connector. The technique is distinguished from other repair techniques by (1) providing a cast clasp replacement, (2) allowing the patient to retain the prosthesis during the repair, (3) generating a precisely formed surveyed clasp assembly by the laboratory, and (4) including an efficient transfer mechanism for the precision clasp created in the laboratory to be attached to the removable partial denture in the dental office. A two-step impression procedure is used to ensure proper relation of the partial denture to the abutments.     

The use of silicone dentures for edentulous patients

There are a number of occasions when a soft denture base will be of much more benefit to an edentulous patient than a conventional rigid prosthesis. This article discusses three such cases.     

Breeding of Philander frenata (Didelphimorphia, Didelphidae) in captivity

STATEMENT OF PROBLEM: Because water sorption of autopolymerizing acrylic reline resins is accompanied by volumetric change, it is a physical property of importance. As residual monomer leaches into the oral fluids and causes tissue irritation, low solubility of these resins is desired. Another requirement is a satisfactory bond between the autopolymerizing acrylic resins and the denture base acrylic resin. PURPOSE: This study compared the water sorption, solubility, and the transverse bond strength of 2 autopolymerizing acrylic resins (Duraliner II and Kooliner) and 1 heat-polymerizing acrylic resin (Lucitone 550). MATERIAL AND METHODS: The water sorption and solubility test was performed as per International Standards Organization Specification No. 1567 for denture base polymers. Bond strengths between the autopolymerizing acrylic resins and the heat-polymerizing acrylic resin were determine with a 3-point loading test made on specimens immersed in distilled water at 37 degrees C for 50 hours and for 30 days. Visual inspection determined whether failures were adhesive or cohesive. RESULTS: Duraliner II acrylic resin showed significantly lower water sorption than Kooliner and Lucitone 550 acrylic resins. No difference was noted in the solubility of all materials. Kooliner acrylic resin demonstrated significantly lower transverse bond strength to denture base acrylic resin and failed adhesively. The failures seen with Duraliner II acrylic resin were primarily cohesive in nature. CONCLUSIONS: Autopolymerizing acrylic reline resins met water sorption and solubility requirements. However, Kooliner acrylic resin demonstrated significantly lower bond strength to denture base acrylic resin.     

Toxicity of metal mixtures to chick embryos

A method of incorporating vertical and horizontal tissues in an obturator impression using an open palate impression tray is presented. The laboratory technique of obturator construction from this impression allows for a definitive (heat-cured) or interim (cold-cured) prosthesis for an edentulous or dentulous patient.     

Effect of polymerization temperature and time on the residual monomer content of denture base polymers

The aim of this study was to investigate the effect of polymerization time and polymerization temperature on the residual methyl methacrylate (MMA) content of two heat-cured and two autopolymerized denture base polymers. Gas chromatography was used to determine the residual MMA content of three test specimens of each type of polymer. Increasing the polymerization temperature for the autopolymerized denture base resins from 30 degrees C to 60 degrees C decreased the residual MMA content of the polymer from an average of 4.6 wt% to 3.3 wt%. With the heat-cured denture base resins, a curing cycle at a polymerization temperature of 70 degrees C followed by a period at 100 degrees C significantly reduced the residual monomer content of the polymer when compared with a resin cured at 70 degrees C only. Polymerizing the heat-cured denture base resin at 100 degrees C only for various lengths of time significantly affected the residual MMA content of the polymer. The lowest residual MMA content (0.07 wt%) was obtained by polymerizing the heat-cured denture base resin at 100 degrees C for 12 h. The results of this study suggest that the polymerization temperature and polymerization time considerably affect the residual MMA content of denture base polymers.     

Provisionalization of a combination implant/natural abutment restoration

This article describes a technique the dental technician can use to fabricate a long-term combination implant and natural tooth provisional prosthesis that will be used to evaluate esthetics and function. This provisional will act as an interim prosthesis while additional implants are healing.     

Testing for carcinogenicity of pharmaceuticals

When two-layered artificial teeth are used, acrylic resin occlusal parts can be removed from base parts and used directly as resin patterns for casting, which facilitates fabrication of metal occlusal surfaces. Because these teeth were made of acrylic resin, it was easy to modify occlusal morphology before converting to metal. Application of two-layered artificial teeth to achieve lingual contact occlusion brought about sufficient masticatory forces and denture stability and resulted in patient satisfaction.     

Fimbrial-mediated colonization of murine teeth by Actinomyces naeslundii

PURPOSE: The hardness, porosity, and adaptation of removable partial dentures fabricated with one heat-polymerized denture base resin and two resins designed for microwave polymerization were evaluated. MATERIALS AND METHODS: Five prostheses were evaluated for each resin. Adaptation of the denture bases to the master cast was evaluated by spatial orientation and mean weight of residual impression material. The prostheses were than embedded in epoxy resin and sectioned for evaluation of resin hardness (Knoop hardness) and microporosity. RESULTS: There were no significant differences in the adaptation of the acrylic resin bases for Acron MC and Ch Lucitone. There was no significant difference in the mean Knoop hardness values for any of the resin bases near and away from the metal. None of the denture bases showed porosity greater than 100 microns. CONCLUSIONS: Both resin bases formulated for microwave polymerization were effectively polymerized around metal frameworks without adverse effects on resin hardness or porosity. Justi Denture Base material had poorer base adaptation than the other two resins.     

A secondary lingual casting for removable partial dentures

This article describes a technique for constructing a nickel chromium alloy lingual casting that reinforces a removable partial denture against heavy anterior occlusion. The metal can be cast into a thin secondary casting, and it is easily etched and bonded to the resin anterior teeth and associated base. This type of lingual casting has the potential to provide a simple and effective solution to the problem of repeated fracture or displacement of anterior teeth in many restorations.     

Bond strength of permanent soft denture liners bonded to the denture base

The purpose of this study was to characterize denture and soft liner adhesion and to determine the adhesive and/or cohesive strength of different soft tissue liners bonded to the denture base by use of a new technique. Two groups of five permanent soft liners (dry or exposed to water for 6 months) were tested by use of a tensile mode to characterize the failure characteristics of soft liners bonded to denture base resin. The method differed from previous test methods because of the specimen's ability to align axially during the test. The results indicated significant differences in the bonding of liners to the denture base, and light-cure systems exhibited the greatest amount of stress needed for failure. Low bond strength was observed when the adhesion was poor or when the cohesive strength of the soft liner was low and lead to pure adhesive or cohesive failure. When both adhesive and cohesive bonds were strong, failure occurred at high stresses. Combinations of adhesive and cohesive failures (mixed mode) were also observed in intermediate cases.     

Immediate addition to acrylic partial dentures

The conventional method of adding teeth to an existing prosthesis has the disadvantage that patients must be without their dentures while the teeth are added. Whilst a new immediate denture avoids this, it means that the patient will have to grow accustomed to the shape of a new polished surface. The method described in this paper eliminates these problems by making an immediate addition to the existing partial denture. Additionally, the technique has been found to be beneficial to those patients who are unable to tolerate conventional impression taking procedures.     

Shock-absorbing behavior of four processed soft denture liners

The cushioning effect of soft denture liners was evaluated with the use of a free drop test with an accelerometer. The materials tested included SuperSoft, Kurepeet-Dough, Molteno Soft, and Molloplast-B brands. All materials were found to reduce the impact force when compared with denture base resin. A 2.4 mm layer of soft denture material demonstrated good shock absorption. The Molloplast-B and Molteno Soft materials showed excellent shock absorption. When the soft denture liner was stored in distilled water for 180 days, the damping effect recorded for all materials tested was increased. The aging of all materials also affected the cushioning effect.     

Pharmacokinetics and toxicity of 120-hour continuous-infusion hydroxyurea in patients with advanced solid tumors

This study investigated the thickness of a swollen layer between heat-activated and autopolymerized denture base polymer based on poly(methyl methacrylate) and autopolymerized repair acrylic resin. The repair surfaces of polymerized poly(methyl methacrylate) resin specimens (n = 5) were wet with methyl methacrylate liquid for 0, 0.5, 3, 30, or 60 minutes before the mixed repair resin was applied and polymerized to the surface of the specimen. The specimens were wet ground to a thickness of 0.15 mm, and the repair joint was examined using a light microscope. The thickness of the layer of swollen poly(methyl methacrylate) at the repair joint was measured from the micrographs. Both the type of polymer, ie, heat-activated or autopolymerized, and the wetting time of the repair surface with methyl methacrylate had a significant effect on the thickness of the swollen layer (P < .001). Prolonged wetting time of the repair surface of the autopolymerized poly(methyl methacrylate) increased the thickness of the swollen layer (r = .944, P = .000), but had less effect on the thickness of the swollen layer of heat-activated poly(methyl methacrylate) (r = .391, P = .005). This study suggests that methyl methacrylate diffuses more easily into an autopolymerized poly(methyl methacrylate) than into heat-activated poly(methyl methacrylate) during the repair of denture base polymer.     

An indirect procedure for making a crown under an existing partial denture

Direct procedures to make a crown under an existing partial denture are inconvenient for the patient. A process is described that uses an irreversible impression of both the crown preparation and the removable prosthesis to fabricate a crown indirectly. The process is efficient and inexpensive.     

Pharmacological activity of fluoxetine

This study introduces a new rapid-processing procedure for curing polymethyl methacrylate denture base resin in an automatically controlled pressure cooker. The cooker filled with water was inflated with 6 kgf/cm2 air pressure and heated to 120 degrees C (248 degrees F) and maintained for 10 minutes. No significant differences were found between the new pressure cooker method and the conventional method for surface hardness and porosity (p > 0.05). The pressure cooker significantly shortened polymerization time, and the polymerization is controlled automatically.     

Use of X-ray diffraction for studying the temperature dependence of the Young modulus of protein crystals

Conventionally, for dental reconstruction after bone grafting of the congenital residual alveolar cleft, a fixed prosthesis or removable partial denture is used. In this paper, residual alveolar cleft reconstruction with an osseointegrated implant following secondary bone grafting is described. The patient underwent secondary bone grafting of the residual alveolar cleft at the age of 18 years. One osseointegrated implant was placed in the bone bridge 8 months after bone grafting. No problems up to 1 year after the fabrication and placement of the fixed prosthesis have been observed.     

Fabricating abutment crowns for existing removable partial dentures using custom resin clasp analogs

A universal approach for fabricating abutment crowns for existing removable partial dentures is described. A replica (analog) of the clasp assembly is generated and transferred to a traditional working cast, which includes the abutment die. The analog is incorporated into the working cast as a removable component to allow the formation of the crown contours. The article reviews in detail the procedures required to transfer accurately all the essential components and information from the mouth to the working cast while allowing the patient uninterrupted use of the removable partial denture. Prestabilizing the removable partial denture, creating the analog impression, avoiding errors due to soft tissue components, forming a precise analog base, selecting materials, generating a rigid resin analog, and prescribing a path of insertion and withdrawal to the analog are described. The method replicates all types of clasps and can generate all types of fixed prosthodontic retainers to function harmoniously with the existing partial denture.     

Mechanical considerations for the implant tooth-supported fixed partial denture

The implant tooth-supported fixed partial denture presents a biomechanical design problem, because the implant is rigidly fixed within the alveolus, and the tooth is surrounded by a periodontal ligament that allows movement. Nonrigid fixed partial denture designs are advocated by some dentists as a method of compensating for this differential movement. Rigid fixed partial denture designs, however, are advocated by many clinicians. Studies have failed to show the advantage of one design over the other. This study developed an in vitro method for testing such prosthesis designs and measured movement of a natural tooth abutment during simulated function. The movement of the natural tooth abutment was not found to change substantially with the fixed partial denture designs tested.