Melbourne Dental School - Research Publications
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ItemDentists' restorative decision-making and implications for an 'amalgamless' profession. Part 5: knowledge factors(WILEY, 2017-12-01)BACKGROUND: A phase-down of amalgam in Australia is possible given the Australian Government intends to ratify the Minamata Convention. There is little research as to the influence of a dentist's knowledge on decision-making, which may be of use when determining the impact of any change. METHODS: An online survey relating to aspects of and attitudes to use of direct restorative materials was distributed to all dentists who were members of the Australian Dental Association or Members or Fellows of the Royal Australasian College of Dental Surgeons. RESULTS: There were 408 respondents. Fifty-eight per cent agreed that there was consistency in undergraduate teaching. Fifty-two per cent stated that there was a difference between undergraduate teaching and the 'real world'. Postgraduate education was ranked the most important influence on decision-making. Ninety-six per cent stated that knowledge of the evidence base is important and 89% believed that they practised evidence-based dentistry. CONCLUSIONS: Dental schools need to maintain teachers' and students' understanding of the evolving technology of direct restorative materials. There is a perceived disconnect between undergraduate teaching and the 'real' world. The evidence base is viewed as confusing, contradictory and not readily understandable. The creation of clinical guidelines would be useful.
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ItemDentists' restorative decision-making and implications for an 'amalgamless' profession. Part 4: clinical factor(WILEY, 2017-09)BACKGROUND: The Minamata Convention embodies a worldwide reduction in the production and use of mercury and mercury-containing products and processes, including a phase-down of dental amalgam. This will change the approach to the use of direct restorative materials in the near future. There is little research as to the influence of clinical factors on dentists' decision-making which may be of use when determining the impact of any change. METHODS: An online survey relating to aspects of and attitudes to the use of direct restorative materials was distributed to all dentists who were members of the Australian Dental Association and/or members or fellows of the Royal Australasian College of Dental Surgeons. Data were statistically analysed. RESULTS: There were 408 respondents to the survey. Eighty-seven per cent of respondents (strongly) disagreed that amalgam was a technically more difficult material to place compared with resin composite, 82% (strongly) disagreed that placement time for amalgam was longer than that for resin composite and 69% (strongly) disagreed that amalgam was more difficult to finish than resin composite. Eighty-three per cent of respondents stated they were confident in their ability to place amalgam restorations. Where physical properties were of importance, indirect restorations were preferred (e.g. parafunction) 54%. The factors considered most important when choosing a direct restorative material included moisture control and aesthetics; least important factors were cost and time to place. CONCLUSIONS: There is consensus that amalgam is not more technically difficult to use, place or finish than resin composite and vice versa. There is recognition that both amalgam and resin composite have limitations in terms of physical properties. When choosing a direct restorative material, clinical factors considered to be of greatest importance are moisture control, aesthetics and the need to apply minimally invasive approaches. There is little difference in the opinions of users and non-users of amalgam with respect to these findings.
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ItemDental educators' attitudes towards the teaching of dental amalgam(WILEY, 2020-05)OBJECTIVE: To ascertain dental educators' attitudes towards the teaching of dental amalgam at dental schools in Australia and identify preferred curricular approaches in a potentially "amalgamless" profession. METHODS: A mixed methods analysis was employed based on an open-ended response survey followed by a closed-ended questionnaire. Identification of key issues from the survey helped frame the questionnaire. Participants included those with expertise in operative and restorative dentistry, with direct involvement in curriculum development or delivery, at Australian dental schools. RESULTS: Participants numbered fifteen and represented seven of the nine dental schools in Australia. Key themes identified and explored included the following: (in)consistency of approach to teaching restorative dentistry; a perceived disconnect between undergraduate study and the "real world"; a need for a focus on teaching of alternatives to dental amalgam (80 per cent (strongly) agreeing); the contradictory nature of the evidence base and literature that is not readily understood; the need for more post-graduate education relating to adhesive restorative materials (86 per cent (strongly) agreeing); the need for dental amalgam to continue to be available; formal understandings (guidelines) as to the use of dental amalgam; dental schools in Australia being heard on these issues; and the relevance of this issue (100 per cent (strongly) agreeing the issue is topical and important). CONCLUSION: There is a broad consensus of dental educators at Australian dental schools as how best to approach the teaching of amalgam if a phase-down is to occur and the issues any such approach may face.
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ItemComparison of two all-in-one adhesives bonded to non-carious cervical lesions-results at 3 years(SPRINGER HEIDELBERG, 2012-08)The aim of this study was to evaluate the clinical performance of S(3) Bond (Kuraray Corp., Japan) and G-Bond (GC Corp., Japan) all-in-one bonding agents, over 3 years in non-carious cervical lesions (NCCLs). Ethics Committee approval was obtained, and 60 restorations were placed in 11 patients aged 45-84 years (mean 60.5 years), using either Clearfil ST resin composite (Kuraray) and S(3) Bond or Gradia resin composite (GC) and G-Bond alternately, without phosphoric acid etch on the uncut enamel margins. Patients were recalled at 6 months, 1 year, 2 years and 3 years, and photographs were taken for assessment of colour match and marginal discoloration. One patient was not available at 3 years, resulting in 54 restorations being available for evaluation. One restoration of S(3)/Clearfil ST was lost at 2 years, giving retention rates of 97% for S(3) and 100% for G-Bond. At 3 years, six restorations for S(3)/Clearfil ST showed slight marginal discoloration and one restoration pronounced marginal staining. For G-Bond/Gradia at 3 years, 11 restorations exhibited slight marginal staining and one restoration pronounced marginal staining. Most restorations were bonded to sclerotic dentin. Statistical analysis of marginal staining showed no significant difference between the two restoration groups. The degree of marginal staining was almost identical for both materials and tended to be in larger restorations. Both S(3) and G-Bond all-in-one bonding systems appear to be good adhesives for the restoration of NCCL for the length of the current study. Restoration of NCCLs with the newer all-in-one adhesives appears to be a viable alternative technique to more complicated adhesive materials.
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ItemDentists' restorative decision-making and implications for an "amalgamless' profession. Part 3: Dentists' attitudes(WILEY-BLACKWELL, 2016-12)BACKGROUND: The Minamata Convention has agreed to a worldwide reduction in the production and use of mercury-containing products and processes. This will change the approach to use of direct restorative materials in the future. There is little research exploring the attitudes of dentists to any change. METHODS: A survey relating to the use of direct restorative materials was distributed to dentists who were members of the Australian Dental Association or Members and Fellows of the Royal Australasian College of Dental Surgeons. Data were statistically analysed. RESULTS: There were 408 respondents. Responses to statements concerning attitudes toward a phase-down of amalgam depended on whether the respondent used amalgam, year of primary dental qualification and association with academia. Thirty per cent of respondents indicated they do not use amalgam. The mean use of amalgam for all direct restorative procedures was 18%. CONCLUSIONS: Dentists are concerned over potential implications of a phase-down of amalgam and much should be done to address these concerns. Many dentists are undecided as to what are the implications, which may reflect a lack of understanding of the issues. It is incumbent on policy-makers to produce and disseminate information relating to the issues identified by this research.
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ItemA comparison of resin-modified glass-ionomer and resin composite polymerisation shrinkage stress in a wet environment(ELSEVIER SCIENCE BV, 2014-01)OBJECTIVE: The aim of this study was to investigate the polymerisation shrinkage stress under water of four resin-modified glass-ionomers and three resin composite materials. METHODS: Transparent acrylic rods (5mm diameter×30mm) were prepared and secured into drill chucks connected to a universal testing machine. A plastics cup was placed around the lower rod and a distance of 1.00mm was established between the prepared surfaces which provided a C-factor of 2.5. For composite only, an adhesive layer (Scotchbond Universal Adhesive) was placed on the rod ends and cured to achieve a bond with the rod end. Materials were placed between the rods and a strain gauge extensometer was installed. Materials were light cured for 40s and the plastics cup was filled with ambient temperature water. To determine polymerisation shrinkage stress (σpol) three specimens of each material were tested for a 6-h period to determine mean maximum σpol (MPa), σpol rate (MPa/s) and final σpol (MPa). ANOVA and post hoc Tukey tests were used to determine significant differences between means. RESULTS: The highest mean maximum σpol of (5.4±0.5) MPa was recorded for RMGIC and (4.8±1.0) MPa for composite. The lowest mean final σpol of (0.8±0.4) MPa was recorded for RMGIC. For mean maximum σpol,σpol rate and final σpol there were significant differences between materials within groups, although no significant difference (p>0.05) was observed when comparing the RMGIC group to the composite group. CONCLUSION: When comparing mean σpol, maximum σpol, and σpol rates between individual RMGIC and composite materials significant differences (p<0.05) were observed. However when comparing the group RMGIC to composite no significant differences (p>0.05) were observed. The null hypothesis that there is no difference in the short term σpol of RMGIC materials when compared to composite materials is only partly rejected. RELEVANCE: Limited information is available on the comparison of RMGIC and resin composite σpol levels. This study provides information on the short term levels in a wet environment and will assist in understanding the initial σpol rates RMGIC place in cavities.
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ItemThe evaluation of four conditioners for glass ionomer cements using field-emission scanning electron microscopy(ELSEVIER SCI LTD, 2001-02)OBJECTIVES: The purpose of this study was to evaluate the GIC-dentine interface morphology using FE-SEM after four different conditioners (Ketac Conditioner, Dentin Conditioner, Cavity Conditioner, and an experimental conditioner K-930), used with two RM-GICs and one self-cured GIC, and to observe the effect with an AFM of the four different conditioners on the surface of polished human dentine. MATERIALS AND METHODS: SAMPLE PREPARATION FOR FE-SEM: Twenty-four 1-mm thick dentine discs were obtained from superficial occlusal dentine of extracted human third molars, and finished with wet 600-grit SiC paper. The discs were treated for each of the GICs using the conditioners according to the manufacturers' instructions. The specimens were kept in tap water for 24 h at 37 degrees C, and then assigned for one of two observational techniques; a fractured technique and an acid-base technique. Specimens were mounted on aluminium stubs, gold sputter-coated and observed using a FE-SEM. SAMPLE PREPARATION FOR AFM: Four rectangular dentine blocks approximately 2mm(3) were prepared from two extracted human third molars, polished and finished with diamond paste down to 0.25 microm particle size. One half of each sample was treated with one of the conditioners according to the manufacturers' instructions, and the other half was not conditioned. The samples were stored in distilled water prior to AFM contact mode observation. RESULTS: FE-SEM: All specimens of all materials demonstrated good adaptation to the underlying dentine. However, the specimens conditioned with K-930 showed increased demineralization and a thicker acid-base resistant layer (2.8-3.4 microm) compared with the others (1-2 microm). AFM: The images of conditioned specimens showed demineralization of peritubular dentine. Funneling of dentinal tubule orifices of specimens conditioned with K-930 was observed, and was also seen for the FE-SEM specimens. SIGNIFICANCE: The use of surface conditioners resulted in similar adaptation to the non-conditioned specimens at the GIC-dentine interface. All of the GICs demonstrated intimate adaptation to the dentine surface whether it was conditioned or not.