RESUMO
PURPOSE: To determine the frequency of insert changes for combined maxillary and mandibular implant overdentures (IOD) using the Locator Legacy system. A secondary objective was to assess the survival of dental implants with IODs. MATERIALS AND METHODS: This retrospective audit reviewed clinical records with up to 12 years follow up from 785 patients who received IODs using the Locator system at a dental hospital. From these, 151 had a combined maxillary opposed by a mandibular IOD and from this, 37 had data retrieved using a minimum data set. The frequency of insert change was recorded and descriptive analysis was provided by means and standard deviations for continuous variables. Frequencies of categorical values were reported as percentages. RESULTS: 222 implants were placed on 21 men, 16 women with a mean age 67.5 years (SD 8.8). All patients were reviewed at least once. Maxillary and mandibular IODs experienced 1.9 (SD 2.0) and 1.2 (SD 1.2) mean insert changes per patient, respectively. The mean time (SD) between initial and first insert change for maxillary and mandibular IODs was 3.4 months (SD 3.2) and 6.4 months (SD 7.2) and between the first and second insert change was 9.9 months (SD 9.0) and 10.0 months (SD 8.3), respectively. Implant failure was 21.6% and 2.7% in the maxilla and mandible respectively. CONCLUSIONS: Clinicians should anticipate the first insert change around 3 months for maxillary IOD and 6 months for mandibular IOD. Subsequently, the second insert change to be around 10 months for both maxillary and mandibular IODs.
RESUMO
OBJECTIVE: The study aimed to investigate the effectiveness of a vacuum impregnation process to eliminate the porosity at the ceramic-resin interface to optimize the reinforcement of a glass-ceramic by resin cementation. METHODS: 100 leucite glass-ceramic disks (1.0 ± 0.1 mm thickness) were air-abraded, etched with 9.6 % HF acid, and silanated. Specimens were randomly allocated to 5 groups (n = 20). Group A received no further treatment (uncoated control). Groups B and D were resin-coated under atmospheric pressure, whereas groups C and E were resin-coated using vacuum impregnation. The polymerized resin-coating surfaces of specimens in groups B and C were polished to achieve a resin thickness of 100 ± 10 µm, while in groups D and E no resin-coating modification was performed prior to bi-axial flexure strength (BFS) determination. Optical microscopy was undertaken on the fracture fragments to identify the failure mode and origin. Comparisons of BFS group means were made by a one-way analysis of variance (ANOVA) and post-hoc Tukey test at α = 0.05. RESULTS: All resin-coated sample groups (B-E) showed a statistically significant increase in mean BFS compared with the uncoated control (p < 0.01). There was a significant difference in BFS between the ambient and vacuum impregnated unpolished groups (D and E) (p < 0.01), with the greatest strengthening achieved using a vacuum impregnation technique. SIGNIFICANCE: Results highlight the opportunity to further develop processes to apply thin conformal resin coatings, applied as a pre-cementation step to strengthen dental glass-ceramics.