METHODS: Twenty patients with two adjacent missing posterior teeth were recruited. Patients were assigned equally and randomly into two groups; Bicon(®) (6 or 8 mm) and Ankylos(®) (8 mm) implants. A two-stage surgical approach and single crowns were used for implant placement and loading. Outcomes included peri-implant clinical parameters, implant stability (Periotest values; PTVs) and peri-implant bone changes, which were assessed at baseline, 2, 6 and 12 months post-loading.
RESULTS: No implant loss was encountered up to 12 months post-loading. No significant difference in the clinical or radiographic parameters was observed except for PTVs (p < 0.05) that was lower in Ankylos(®) implants.
CONCLUSIONS: The use of short dental implants was associated with excellent 12 months clinical and radiographic outcomes. Ankylos(®) and Bicon(®) implants demonstrated similar peri-implant soft tissue and alveolar bone changes. However, Ankylos(®) implants demonstrated better implant stability at all evaluation intervals.
MATERIALS AND METHODS: Three-dimensional solid models of the maxilla, mucosa, and denture of a selected edentulous patient were created using Mimics and CATIA software. The FEA model was created and duplicated in ANSYS 16.0 to perform two simulations for the IOD and the CD models. The values of maximum stress and strain and total deformation were obtained and compared to the outcomes of premaxilla resorption from a parallel clinical study.
RESULTS: The maximum principal stress in the premaxilla in the IOD model ranged from 0.019 to 0.336 MPa, while it ranged from 0.011 to 0.193 MPa in the CD model. The maximum principal strain in the IOD model was 1.75 times greater than that in the CD model. Total deformation was 1.8 times higher in the IOD model. Greater bone resorption was observed in regions of higher stress, which were on the occlusal and buccal sides of the premaxilla residual ridge.
CONCLUSION: Stress, strain, and total deformation values present in the premaxilla area beneath a CD were approximately two times greater in a comparison between an opposing mandibular two-IOD and an opposing mandibular CD. The results were consistent with a parallel clinical study in which the rate of premaxilla bone resorption was almost three times greater in the IOD group.
MATERIALS AND METHODS: 18 patients were rehabilitated with maxillary CD opposing mandibular IRO, and 4 patients were prescribed with conventional CD. Cone beam computed tomography (CBCT) scans of the maxilla were acquired before and 1 year post-treatment and converted into 3D models using Mimics research software. RRR was quantified by measuring the changes in bone volume following superimpositioning and sectioning of these models at the anterior maxillary region. Subsequently, the sectioned 3D models of the anterior maxilla were exported to 3-Matic software to reveal the predominant region and depth of RRR.
RESULTS: The mean reduction in bone volume of the anterior maxilla in the CD group was 2.60% (SD = 1.71%, range = -4.89 % to -0.92%, median = -2.30%), while the mean reduction in the IRO group was almost three times higher at 7.25% (SD = 3.16%, range = -13.25 to -1.50, median = -7.15%). The predominant areas of RRR were on the buccal and occlusal ridge of the anterior maxilla.
CONCLUSION: Within the limits of this study, it may be concluded that an IRO caused significantly higher RRR of the anterior maxilla than a CD.
MATERIALS AND METHODS: The test group included 9 participants rehabilitated by maxillary CD opposing mandibular IRO, while the control group consisted of 4 participants with CDs. Blood flow was measured by laser Doppler flowmetry (LDF) after denture removal for 0, 30, 60, and 90 minutes. RRR was quantified as reduction in bone volume a year post-treatment. The measurement of blood flow was then compared to the quantification of RRR.
RESULTS: The mean blood flow measure for the IRO group was significantly lower than CD after immediate denture removal and 30 minutes later. After 60 minutes, the mean difference was not significant between groups, and at 90 minutes, the mean blood flow of both groups equalized to reach a steady state of 377 BPU. The mandibular IRO had reduced the initial blood flow measure in the opposing anterior maxilla mucosa to almost a quarter (103 BPU) of the steady state value (377 BPU) compared to the CD, which reduced it to only about one half (183 BPU), suggesting greater blood flow disturbance in the IRO group. This result is in tandem with the greater reduction of bone volume observed in the IRO group, which was 7.3 ± 1.3% after a year, almost three times higher than CD group at 2.6 ± 1.7%.
CONCLUSION: IRO may cause significantly higher blood flow disturbance than CD and may have contributed to greater RRR in the anterior maxilla.
MATERIAL AND METHODS: Thirty-four patients (mean age 60.70 ± 8.7 years) received telescopic crown or locator attachments for ISOD and completed OHIP-14 (Malaysian version) and DS questionnaires, at baseline (T0 ) with new conventional complete dentures (CCD) and 3 months (T1 ) and 3 years (T2 ) after ISOD conversion. Mandibular bone volume was calculated from cone beam computed tomography (CBCT) datasets using Mimics software. Mean changes (MC) in OHIP-14 and DS at intervals were analyzed using the Wilcoxon signed-rank test and effect size (ES). The association of bone volume, implant attachment type, and other patient variables with the change in OHIP-14 and DS were determined using multivariate linear regression analysis.
RESULTS: The MC in OHIP-14 and DS scores from T0 to T1 and T2 showed significant improvement with moderate and large ES, respectively. Regression analyses for the change in OHIP-14 score from T0 to T2 showed significant association with implant attachment type (P = 0.043), bone volume (P = 0.004), and baseline OHIP-14 (P = 0.001), while for DS, the association was only significant with baseline DS score (P = 0.001).
CONCLUSION: Improvement in patients' OHRQoL and satisfaction with ISOD was associated with their baseline ratings. Mandibular bone volume had a stronger association for improvement in OHRQoL compared to type of attachment.
PURPOSE: The purpose of this prospective clinical study was to evaluate the changes in masticatory function from baseline (T0) to 3 months (T1) and 3 years (T2) in participants with MODs and to assess the effect of baseline mandibular bone height and volume on masticatory function after 3 years.
MATERIAL AND METHODS: Participants were assessed for masticatory function by using masticatory performance involving paraffin wax cubes as an objective measure and by using masticatory ability involving a questionnaire as a subjective measure. Edentulous individuals presenting for replacement dentures were provided with conventional mucosa-supported prostheses and evaluated for masticatory function after a 3-month settling-in period (baseline measure). Before implant placement, baseline measures of bone height and volume were recorded from cone beam computed tomography (CBCT) images. The prostheses were then converted to implant-stabilized mandibular overdentures while any maxillary prostheses remained supported by the mucosa. Masticatory function was reassessed at 3 months and 3 years after insertion of the mandibular overdentures, and the mean changes from baseline were analyzed with the Wilcoxon signed-rank test. The effect of variables on masticatory function was determined by using multivariate linear regression analyses.
RESULTS: A total of 23 participants were included in the study, with only 1 participant not completing the 3-year assessment. Significant improvement was observed in the masticatory performance (mixing ability index) (Pimplant-stabilized mandibular overdenture.
CONCLUSIONS: Masticatory function significantly improved after 3 months and was maintained over 3 years in participants with implant-stabilized mandibular overdentures. However, baseline bone height and volume had no significant effect on these changes in masticatory function after 3 years.
MATERIALS AND METHODS: The literature search was carried out on two electronic databases (PubMed and Cochrane Library). Randomized controlled trials (RCT) published from January 2011 to September 2022 were included. The bias risk was evaluated using Cochrane Risk of Bias Tool 2.0. Further screening was done for meta-analysis according to modified Newcastle-Ottawa scoring criteria. Forest plot was generated using a statistical method of inverse variance of random effect with 95% confidence interval.
RESULTS: A total of 8 randomized controlled trials were included for systematic review out of which four studies were based on tooth-supported fixed prosthesis and remaining four were based on implant-supported prosthesis. Further screening was conducted and three studies were eligible for meta-analysis. Tooth-supported fixed prosthesis fabricated from digital impression showed no significant difference in the marginal fit in any region measured, except for occlusal region where conventional impression showed more favorable marginal fit. Implant-supported prosthesis fabricated from digital impression showed survival rates ranging from 97.3 to 100% and there was no statistically significant difference in marginal bone loss (p = 0.14).
CONCLUSION: Implant-supported prostheses fabricated from digital and conventional impressions show no significant differences in their clinical outcomes. Tooth-supported fixed prostheses fabricated from digital impression have shown favorable findings in terms of marginal fit. Despite that, there is still lack of clinical trials with larger sample size and longer follow-up periods. Future studies that fulfill these two criteria are deemed necessary.