PURPOSE: The purpose of this finite element analysis study was to evaluate the biomechanical behavior (stress distribution pattern) in the mandibular overdenture, mucosa, bone, and implants when retained with 2 standard implants or 2 mini implants under unilateral or bilateral loading conditions.
MATERIAL AND METHODS: A patient with edentulous mandible and his denture was scanned with cone beam computed tomography (CBCT), and a 3D mandibular model was created in the Mimics software program by using the CBCT digital imaging and communications in medicine (DICOM) images. The model was transferred to the 3Matics software program to form a 2-mm-thick mucosal layer and to assemble the denture DICOM file. A 12-mm-long standard implant (Ø3.5 mm) and a mini dental implant (Ø2.5 mm) along with the LOCATOR male attachments (height 4 mm) were designed by using the SOLIDWORKS software program. Two standard or 2 mini implants in the canine region were embedded separately in the 3D assembled model. The base of the mandible was fixed, and vertical compressive loads of 100 N were applied unilaterally and bilaterally in the first molar region. The material properties for acrylic resin (denture), titanium (implants), mucosa (tissue), and bone (mandible) were allocated. Maximum von Mises stress and strain values were obtained and analyzed.
RESULTS: Maximum stresses of 9.78 MPa (bilaterally) and 11.98 MPa (unilaterally) were observed in 2 mini implants as compared with 3.12 MPa (bilaterally) and 3.81 MPa (unilaterally) in 2 standard implants. The stress values in the mandible were observed to be almost double the mini implants as compared with the standard implants. The stresses in the denture were in the range of 3.21 MPa and 3.83 MPa and in the mucosa of 0.68 MPa and 0.7 MPa for 2 implants under unilateral and bilateral loading conditions. The strain values shown similar trends with both implant types under bilateral and unilateral loading.
CONCLUSIONS: Two mini implants generated an average of 68.15% more stress than standard implants. The 2 standard implant-retained overdenture showed less stress concentration in and around implants than mini implant-retained overdentures.
MATERIALS AND METHODS: Twenty-one patients with implants were included in this study and implants were assessed by resonance frequency analysis (RFA). Bone levels of the implants were assessed by measuring mesial and distal bone levels from the periapical radiograph, and soft tissue was assessed from probing depth using a periodontal probe. Implants were assessed for stability and probing depth at pre-loading, at 3 months and 6 months post-loading. RFA and probing depth were statistically compared from different time points. Correlation of probing depth and marginal bone loss with implant stability was also determined.
RESULTS: The average change in implant stability quotient (ISQ) measurements from pre-loading to 6 months post-loading was found to be statistically significant (p <0.005). The average probing depth reduced from 1.767 mm at pre-loading to 1.671 mm at post-loading 3 months, and 1.600 mm at post-loading 6 months. At 6 months of function, radiographic examination yielded 0.786 mm mesial bone loss and 0.8 mm distal bone loss. It was found to be statistically significant (p <0.005) but within an acceptable range. No significant correlation was found between implant stability and bone loss; and implant stability and probing depth.
CONCLUSION: The study revealed an increasing trend in implant stability values with the time that indicates successful osseointegration. Increasing mean values for mesial and distal bone loss were also found.
CLINICAL SIGNIFICANCE: The success of dental implants is highly dependent on the quality of bone and implant-bone interface, i.e., osseointegration. The most important factors that influence the survival rate of an implant is initial stability. The present study found the changes in the peri-implant hard and soft tissues and implant stability. This article, while being a prospective study, may show the evidence of successful osseointegration by increasing trend in implant stability (RFA) values with time which can help to the clinician in the long-term management of implants.
METHODOLOGY: Five electronic databases were searched for studies that compared implant outcomes in patients with differing HbA1c values. Research quality was evaluated using Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tool. Narrative synthesis and meta-analysis were performed for survival rate, plaque index (PI), bleeding on probing (BOP), probing pocket depth, and marginal bone loss (MBL). Categorical dose-response meta-analysis (DRMA) was conducted according to length of follow-up.
RESULTS: Twenty-two studies met the inclusion criteria. Prospective studies were mostly of moderate quality, but non-prospective papers had serious to critical risk of bias. Survival rate was high for the first 3 years (92.6%-100%) for patients with HbA1c less than 8%. Meta-analysis revealed worsening clinical parameters with increasing HbA1c. DRMA further established a significant dose-response relationship between glycemic control with BOP (10% more bleeding, 95% CI 0.05-0.16, P = .008) and MBL (0.05 mm more bone loss, 95% CI 0.01-0.09, P = .002) per HbA1c category, but no association with probing pocket depth. Osseointegration progressed at a slower rate, and inflammatory cytokines and bone biomarkers were adversely affected in patients with HbA1c above 8%.
CONCLUSION: Moderate evidence suggests a high short-term survival but possible dose-response trend of worsening BOP and MBL in association with glycemic control. Clinically, HbA1c values must be considered for risk assessment before placement and throughout the lifespan of the implant placed in a patient with diabetes.
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) (P
Materials and Methods: A total of 100 CBCT-Digital Imaging and Communications in Medicine files of the patients of 3 ethnic populations (Malay, Chinese and Indian) between the ages of 18 and 80 years were selected for the study. The files were imported onto the iCAT software. The measurements of the SIDIAN to the lower border of the mandible in molar regions were done on both sides. The data was analysed using t-test, one-way analysis of variance test, and correlation coefficient test via the SPSS software.
Results: Statistically significant positive correlations were identified between the SIDIAN from the lower border of the mandible in the first and second molar regions within the same side as well as between both sides of the mandible (r ≈ 0.8). There were no statistically significant differences between genders. However, there were statistically significant differences on both molar regions and on both sides in all three ethnic groups (P < 0.05). In general, the SIDIAN from the lower border of the mandible was greatest amongst Chinese and smallest amongst Indians.
Conclusions: The strong positive correlations on both sides of the mandible indicate the presence of symmetry. Ethnicity-related variations exist in terms of the location of the IAN in the mandible.
MATERIALS AND METHODS: Overall methods were guided by the Core Outcome Set Measures in Effectiveness Trials (COMET) initiative. Initial outcome identification was achieved from focus groups with PWLE employing calibrated methods across two low-middle-income countries (China and Malaysia) and two high-income countries (Spain and the United Kingdom). Following consolidation of the results, the outcomes were incorporated into a three-stage Delphi process with PWLE participation. Finally, consensus between PWLE and DPs was achieved using a mixed live and recorded platform. The experiences of PWLE involvement in the process was also evaluated.
RESULTS: Thirty-one PWLE participated in four focus groups. Thirty-four outcomes were suggested across the focus groups. Evaluation of the focus groups revealed a high level of satisfaction with the engagement process and some new learning. Seventeen PWLE contributed to the first 2 Delphi rounds and 7 to the third round. The final consensus included 17 PWLE (47%) and 19 DPs (53%). Out of the total of 11 final consensus outcomes considered essential by both PWLE and health professionals, 7 (64%) outcomes mapped across to ones that PWLE initially identified, broadening their definition. One outcome (PWLE effort required for treatment and maintenance) was entirely novel.
CONCLUSIONS: We conclude that engaging PWLE in COS development can be achieved across widely different communities. Furthermore, the process both broadened and enriched overall outcome consensus, yielding important and novel perspectives for health-related research.