Factors influencing long-term restoration survival in three private dental practices in Adelaide

Very little is known of dentist and patient factors which may influence the survival or longevity of dental restorative materials placed in private practices. The present retrospective study investigated during 1992 the effects of six factors on the long-term survivals of five types of restorations placed by 20 male dentists in 100 adult patients, at 3 selected Adelaide dental practices. There were no significant effects on restoration survival from change of dentist, and generally only one or two types of restorations had their survivals influenced significantly either by dental practice location, or by patient age, frequency of patient attendance, experience of dentist, and whether or not the restorations were replacements during the study period. Restoration survival was not influenced significantly by whether, or not, any replacements were made by the dentist who placed the initial restorations. The median survival times for amalgams were 22.52 years, resin composites 16.72 years, castings 13.75 years, and crowns an estimated 26 years. For glass-ionomers, 75 per cent were still present at 11.25 years.     

General hospital residency for dental undergraduates

A one-week full-time general hospital residency for a final year of 81 dental undergraduates has been greeted by the majority of students as being an invaluable experience. Such a residency programme could be structured to provide dental students with an even broader medical perspective during their training and thus allow for a greater clinical maturity on graduation. The present programme is outlined and discussed.     

Prosthodontic procedures for implant reconstruction. 1. Diagnostic procedures

The University of Sydney Dental School and more recently the Implant Centre have been treating patients with the Brånemark Osseointegration Implant System since 1981. Success depends on close cooperation between surgeon and prosthodontist. This paper describes specific prosthodontic treatment planning procedures based on a general knowledge of prosthodontics, and detailed methods for determining the position, length and alignments of the implants for a specific case by the use of radiographic and surgical templates.     

Infection control in general dental practice

A postal survey of 600 dental practitioners in New South Wales was conducted in 1986 to establish a data base on current infection control protocols as they apply to everyday dental practice. Three hundred and sixty-three replies (60 per cent) were returned, representing approximately 16 per cent of Australian Dental Association members in New South Wales (1987).     

Trans-antral temporalis transfer for the repair of adult cleft palates

Temporalis muscle transfer is a versatile technique frequetly used for reconstructive procedures in the maxillofacial region. However the thickness of the pedicle may interfere with masticatory function when used anteriorly in the oral cavity. To repair full-length mid-palatal defects in fully dentate patients the flap can be passed through the maxillary sinus and combined with local repair of the soft palate, thus avoiding any occlusal trauma from the posterior teeth.
The operation is a single stage procedure with low morbidity and few complications, and is a useful technique for repairing the large untreated clefts frequently encountered in developing countries. The procedure is used by members of the Australian and New Zealand Association of Oral and Maxillofacial Surgeons Bangladesh Project who have operated in Dhaka teaching hospitals on a regular basis since 1991.     

An In Vitro Investigation of a Comparison of Bond Strengths of Composite to Etched and Air-Abraded Human Enamel Surfaces

PURPOSE: The purposes of the study were to measure the tensile bond strength of composite resin to human enamel specimens that had been either etched or air-abraded, and to compare the quality of the marginal seal, through the assessment of microleakage, of composite resin to human enamel specimens that had been either etched or air-abraded. MATERIALS AND METHODS: Thirty mandibular molar teeth were decoronated and sectioned mesio-distally to produce six groups, each containing ten specimens that were embedded in acrylic resin using a jig. In each of the four treatment groups, the specimen surfaces were treated by either abrasion with 27 or 50 microm alumina at 4 mm or 20 mm distance, and a composite resin was bonded to the treated surfaces in a standardized manner. In the two control groups the specimens were treated with 15 seconds exposure to 36% phosphoric acid gel and then similarly treated before being stored in sterile water for 1 week. All specimens were then subjected to tensile bond strength testing at either 1 or 5 mm/min crosshead speed. For the microleakage study, the degree of dye penetration was measured 32 times for each treatment group, using a neutral methylene blue dye at the interface between composite and either 27 or 50 microm air-abraded tooth structure or etched enamel surfaces. RESULTS: The mean bond strength values recorded for Group 1 (phosphoric acid etch, 5 mm/min crosshead speed) was 25.4 MPa; Group 2 (phosphoric acid etch, 1 mm/min), 22.2 MPa; Group 3 (27 microm alumina at 4 mm distance), 16.8 MPa; Group 4 (50 microm alumina at 4 mm distance), 16.9 MPa; Group 5 (27 microm alumina at 20 mm distance), 4.2 MPa; and for Group 6 (50 microm alumina at 20 mm distance) 3.4 MPa. An analysis of variance (ANOVA) demonstrated significant differences among the groups, and a multiple comparison test (Tukey) demonstrated that conventionally etched specimens had a greater bond strength than air-abraded specimen groups. No significant difference in dye penetration could be demonstrated among the groups (p= 0.58). CONCLUSIONS: Composite resin applied to enamel surfaces prepared using an acid etch procedure exhibited higher bond strengths than those prepared with air abrasion technology. The abrasion particle size did not affect the bond strength produced, but the latter was adversely affected by the distance of the air abrasion nozzle from the enamel surface. The crosshead speed of the bond testing apparatus had no effect on the bond strengths recorded. The marginal seal of composite to prepared enamel was unaffected by the method of enamel preparation.     

Oral submucous fibrosis. Case report and review of the literature

A case history and brief literature review of oral submucous fibrosis is presented. This condition is most frequently found in the Indian subcontinent and only rarely encountered elsewhere. The aetiology is considered to be related to dietary habits and customs found in the population. The condition has a known malignant potential. With increasing migration to Australia from the Indian subcontinent the condition should be known and recognized by clinicians.     

Gap measurement and bond strength of five selected adhesive systems bonded to tooth structure

The ability of a restorative material to bond and seal the interface with tooth structure is perhaps the most significant factor in determining resistance to marginal caries. Thus, the quality and durability of marginal seal and bond strength are major considerations in the selection of restorative materials. The purpose of this study was to compare the bond strength and marginal discrepancies of five adhesive systems: All-Bond 2, Clearfil Liner Bond, KB 200, ProBond and AELITE Bond. Twenty-five buccal and 25 lingual cavities were prepared in 25 caries-free extracted molar teeth, giving 10 cavities for each of the 5 adhesive systems. All teeth were restored with the resin composite Pertac Hybrid, or PRISMA Total Performance Hybrid with their appropriate adhesive systems. After restoration, the teeth were thermocycled, were stained with a 1.5% aqueous solution of a procion dye (reactive orange 14) and sectioned coronally with a saw microtome. Three sections of 200 μm thickness were prepared from each restoration which were then examined microscopically to measure marginal gap widths using a confocal tandem microscope. Shear bond strength measurements were carried out on the dentine bond using a universal testing machine. The All-Bond 2 adhesive system was found to have higher shear bond strength and to have the least gap with at the cementodentinal margin.     

Odontogenic myxoma: Case report with reconstructive considerations

Odontogenic myxoma is a benign but locally aggressive neoplasm. The present case documents the resective and reconstructive management of a patient with a moderately large myxoma of the mandible.     

Post-extraction bleeding—An aid to diagnosis? Case report

Haemophilia A, the most common of bleeding disorders is characterzed by bruishing and spontaneous bleeding into the joints but may remain undiagnosed if present in the mild form. A case is discussed where episodes of bruising and joint sweelling as a child were misdiagnosed as rheumatic fever and the bleeding disorder was diagnosed following recurrent episodes of bleeding after extraction of an upper molar tooth.