Melbourne Dental School - Research Publications
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ItemBiological considerations of dental materials as orifice barriers for restoring root-filled teeth(Wiley, 2023)There is ample published literature regarding the technical aspects of restoring root-filled teeth, but little concerning the biological impacts, consequences, and criteria for the selection of direct restorative materials following endodontic treatment. The provision of an effective coronal seal in addition to a sound root filling is known to be important in the prevention of root canal infection. This review seeks to explore the evidence concerning the selection of dental materials in the restoration of root-filled teeth, specifically with a close examination of the properties of commonly used materials as orifice barriers.
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ItemAntibiotic Exposure and Dental Health: A Systematic Review(AMER ACAD PEDIATRICS, 2023-07)CONTEXT: The use of antibiotics in young children is widespread and may lead to adverse effects on dental health, including staining, developmental defects, and dental caries. OBJECTIVE: To systematically review the effects of early childhood antibiotic exposure on dental health. DATA SOURCES: Medline (Ovid/PubMed), Embase (Ovid) and Cochrane databases. Study bias was assessed using the Newcastle-Ottawa Scale. STUDY SELECTION: English language articles that reported antibiotic exposure before 8 years of age and 1 or more of the relevant outcomes (dental caries, intrinsic tooth staining, or developmental defects of enamel) were included. DATA EXTRACTION: Data on study population, design, type of antibiotic, outcome measurement, and results were extracted from the identified studies. RESULTS: The initial search yielded 1003 articles of which 34 studies were included. Five of the 18 studies on tetracycline described a dose response relationship between exposure to tetracycline doses of > 20 mg/kg per day and dental staining. Early childhood exposure to doxycycline (at any dose) was not associated with dental staining. There was no clear association between any early childhood antibiotic exposure and dental caries or enamel defects. LIMITATIONS: In all included studies, the main limitations and sources of bias were the lack of comparison groups, inconsistent outcome measures, and lack of adjustment for relevant confounders. CONCLUSIONS: There was no evidence that newer tetracycline formulations (doxycycline and minocycline) at currently recommended dosages led to adverse effects on dental health. Findings regarding antibiotic exposure and developmental defects of enamel or dental caries were inconsistent. Further prospective studies are warranted.
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ItemPrevalence and morphology of C-shaped and non-C-shaped root canal systems in mandibular second molars(WILEY, 2022-07-04)BACKGROUND: There are no cone-beam computed tomography (CBCT)-based data on the anatomy of mandibular second molars in an Australian population. This study investigated the prevalence and descending morphology of mandibular second molars with and without C-shaped canals using retrospective analysis of CBCT scans. METHODS: Scans from 715 patients were screened for the presence of C-shaped canals and assessed for cross-sectional configuration at five axial levels. Non-C-shaped molars were assessed for other morphological characteristics. Data were modelled against patient, tooth and CBCT scan characteristics. RESULTS: A total of 1278 teeth from 657 patients were evaluated. The overall prevalence of C-shaped canals was 13%. Cross-sectional configuration of C-shaped canals was variable, with an average of 2.8 unique cross-sections per tooth. Non-C-shaped teeth were predominantly Vertucci Type II (60%) and Type IV (29%) configurations in mesial roots, and Type I (91%) in distal roots. Additional roots occurred in 4.3% of teeth and there was a significant association between radix paramolaris and distal root bifurcation (P < 0.001). CONCLUSIONS: Cross-sectional analysis confirmed the complexity and variability of C-shaped canals. Clinicians should be cognizant of the prevalence and variability of C-shaped root canal morphology and how this may affect endodontic treatment.
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ItemEffect of CPP-ACP modified-GIC on prevention of demineralization in comparison to other fluoride-containing restorative materials(WILEY, 2022-03-11)BACKGROUND: This study evaluated the ability of a CPP-ACP-modified Glass-ionomer cement (GIC) to inhibit demineralization around the margins of cervical cavities in natural teeth in comparison with a Giomer and conventional GIC with and without coating. METHODS: Thirty-two sound human molars were used. Box-shaped cavities were prepared along the CEJ. Teeth were randomly divided into four groups and restored with Equia Forte Fil, Coated Equia Forte Fil, Fuji VII EP or Beautifil II. Teeth were subjected to pH cycling. Micromorphological and elemental analyses were done using SEM and EDX. Polarized light microscope analysis and microhardness tests were also performed. RESULTS: Microhardness tests on enamel showed a significant difference between the coated Equia group, Equia and Beautifil II groups (P < 0.05). Dentine results showed significant differences between the coated Equia group and all other groups (P < 0.05). Elemental analysis showed significant differences in calcium weight percentage among the first and second observation levels in all groups (P < 0.05). A significant difference was found between the coated Equia group and the other three groups (P < 0.05). CONCLUSIONS: All tested materials showed some ability to resist demineralization at the restoration margins. The coated GIC restoration showed better outcomes compared with the other tested materials.
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ItemAn In Vitro Evaluation of the Effect of 3D Printing Orientation on the Accuracy of Implant Surgical Templates Fabricated By Desktop Printer(WILEY, 2022-02-09)PURPOSE: To evaluate the effect of different 3D printing orientations on internal and seating accuracy of implant surgical templates fabricated by a digital light processing (DLP) printer. MATERIALS AND METHODS: A single maxillary model with a missing central incisor was used to design a surgical template for single implant placement. According to the printing orientation, three surgical template groups were included in the study: horizontal (H), angled (A) and vertical (V) (n = 10). For the H group, the templates were produced parallel to the printing platform, while for the V group, the templates were perpendicular to the platform. The A group templates had a 45° angle orientation to the platform. Each template was scanned at the fitting surface and after seating on the master model. The internal accuracy involved measuring the trueness and precision of the internal surface, while for the seating accuracy, the vertical discrepancy after seating the template was measured. To determine the difference among the groups, ANOVA test was applied followed by Tukey post hoc tests (α = 0.05). RESULTS: The H group had the lowest internal surface inaccuracy (trueness = 100.7 μm; precision = 69.1 μm) followed by A (trueness = 114.0 μm; precision = 77.3 μm) and V (trueness = 120.3 μm; precision = 82.4 μm) groups, respectively (p < 0.001). Similarly, the H group had the most superior seating accuracy (543.8 μm) followed by A group (1006.0 μm) and V group (1278.0 μm), respectively (p < 0.001). CONCLUSIONS: The orientation of 3D printing of implant surgical templates fabricated by the DLP desktop printer influenced the accuracy of the templates. The horizontally printed templates consistently exhibited superior accuracy. To reduce deviation of implant placement, it is recommended to print the surgical templates with their largest dimension parallel to the printing platform.
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ItemDenosumab and invasive cervical root resorption: a case report(WILEY, 2022-02-06)
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ItemOperating time for wire ligation with self-ligating and conventional brackets: A standardized in vitro study(WILEY, 2022-08-26)OBJECTIVE: Operating time is one of the main advantages attributed from the literature to the use of self-ligating brackets (SLB). The aim of this study is to investigate the time needed for a complete archwire change procedure with conventional brackets (CB) and SLBs in a standardized in vitro research setting, comparing operators with different expertise. MATERIALS AND METHODS: Thirty-three participants were divided into three equal groups: undergraduate students, postgraduate students, and orthodontists. Three sets of typodonts bonded with three types of brackets, including passive SLBs, active SLBs, and CBs using both steel and elastic ligatures were investigated. Operators had to insert, ligate, deligate, and remove wires in sets of typodonts representing an actual dentition before and after orthodontic treatment, mounted in phantoms. Archwire change procedure times were compared between the different bracket/ligation systems, between the before- and after-treatment typodonts, and between operators. RESULTS: There were significant differences between SLBs and CBs, the greatest difference being 11 min 16 s between passive SLBs and CBs ligated with metallic ligatures at T0, for the total archwire change procedure by the operators overall. For all the operators, there was a statistically significant difference in total archwire change procedure time between the systems. The undergraduate students were the slowest when using CBs, but they showed no significant difference compared to the other users when using SLBs. CONCLUSION: SLBs can offer a significant operating time reduction compared to CBs, and time saving is not dependent on the operator's experience and training.