PURPOSE: The purpose of this 3D finite element analysis study was to evaluate the biomechanical behavior of 2-implant mandibular overdentures (2IMO) and their individual components by using implants of different diameters.
MATERIAL AND METHODS: A 3D mandibular model was obtained from the cone beam computed tomography (CBCT) images of a 59-year-old edentulous man, and a 3D denture model was developed from intraoral scanning files in the Mimics software program. A 3D model of different diameters of implants (2.5 mm, 3.0 mm, 3.5 mm, and 4.0 mm) with a LOCATOR attachment was developed in the Solidworks software program. Two same-sized implants were inserted in the mandibular model at 10 mm from the midline in the 3Matics software program. A vertical load of 100 N was applied on the first molar region on the right side or both sides in the ANSYS software program. The maximum von Mises stresses and strains were recorded and analyzed.
RESULTS: Stresses within the implants decreased with an increase in diameter (from 2.5 mm to 3 mm, 3.5 mm, and 4.0 mm) of the implants. The highest stresses were observed with 2.5-mm-diameter implants (0.949 MPa under unilateral and 0.915 MPa under bilateral loading) and the lowest with Ø4-mm implants (0.710 MPa under unilateral and 0.703 MPa under bilateral loading). The strains on the implants ranged between 0.0000056 and 0.0000097, and those on the mandible ranged between 0.0000513 and 0.0000566 across all diameters of the implants without following a specific trend.
CONCLUSIONS: In 2IMO, the stresses in the implants and mandible decreased with an increase in the diameter of the implants. The implants of lesser diameter (2.5 mm) exhibited the highest stresses and strains, and the implants of the largest diameter (4 mm) exhibited the lowest stresses and strains under unilateral and bilateral loading conditions.
PURPOSE: The purpose of this in vitro study was to evaluate the crestal strain around 2 implants to support mandibular overdentures when placed at different positions.
MATERIAL AND METHODS: Edentulous mandibles were 3-dimensionally (3D) designed separately with 2 holes for implant placement at similar distances of 5, 10, 15, and 20 mm from the midline, resulting in 4 study conditions. The complete denture models were 3D designed and printed from digital imaging and communications in medicine (DICOM) images after scanning the patient's denture. Two 4.3×12-mm dummy implants were placed in the preplanned holes. Two linear strain gauges were attached on the crest of the mesial and distal side of each implant (CH1, CH2, CH3, and CH4) and connected to a computer to record the electrical signals. Male LOCATOR attachments were attached, the mucosal layer simulated, and the denture picked up with pink female nylon caps. A unilateral and bilateral force of 100 N was maintained for 10 seconds for each model in a universal testing machine while recording the maximum strains in the DCS-100A KYOWA computer software program. Data were analyzed by using 1-way analysis of variance, the Tukey post hoc test, and the paired t test (α=.05).
RESULTS: Under bilateral loading, the strain values indicated a trend with increasing distance between the implants with both right and left distal strain gauges (CH4 and CH1). The negative (-ve) values indicated the compressive force, and the positive (+ve) values indicated the tensile force being applied on the strain gauges. The strain values for CH4 ranged between -166.08 for the 5-mm and -251.58 for the 20-mm position; and for CH1 between -168.08 for the 5-mm and -297.83 for the 20-mm position. The remaining 2 mesial strain gauges for all 4 implant positions remained lower than for CH4 and CH1. Under unilateral-right loading, only the right-side distal strain gauge CH4 indicated the increasing trend in the strain values with -147.5 for the 5-mm, -157.17 for the 10-mm, -209.33 for the 15-mm, and -234.75 for the 20 mm position. The remaining 3 strain gauges CH3, CH2, and CH1 ranged between -28.33 and -107.17. For each position for both implants, significantly higher (P
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.
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.
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.
MATERIALS AND METHODS: Two reviewers independently searched two electronic databases, PubMed and Scopus. The search was complemented from references of included studies and published reviews. Studies published in the English language through January 2021 that had assessed and documented the clinical and radiographic failure of crown or FPD in vital permanent teeth due to pulpal or periapical pathology with a follow-up of at least 12 months were selected. Data screening, data collection and extraction of data was performed. Quality of studies involved was analyzed using the Newcastle-Ottawa Quality Assessment Scale for cohort studies. Meta-analysis was done using random effects model. Publication bias was assessed using funnel plots.
RESULTS: Electronic searches provided 10,075 records among which 20 studies were selected for systematic review and 7 studies were selected for meta-analysis. With respect to quality assessment, all the studies involved were considered as high quality as the score in scale ranged between 6 and 9 as per the Newcastle-Ottawa Quality Assessment Scale for cohort studies. The meta-analyses showed that there was no statistically significant difference in the incidence of the loss of pulp vitality or pulp necrosis through clinical and radiographic examination with the follow up period of 5 years: p < 0.001, 95% CI: 0.96-1.00, I2 = 77.84%; 10 years: p < 0.001, 95% CI: 0.88-0.95, I2 = 93.59%; 15 years: p < 0.001, 95% CI: 0.92-0.96, I2 = 94.83%; and 20 years: p < 0.001, 95% CI: 0.94-0.96, I2 = 95.01%.
CONCLUSIONS: The meta-analysis revealed clinical and radiographic success rate ranging between 92% to 98% at different follow up periods ranging between 5 years and 20 years. Future high-quality randomized clinical controlled trials with a larger population are required to confirm the evidence as only observational studies were considered in this paper.
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 systematic review of the literature and meta-analysis was to analyze the data on the survival of dental implants in patients with HIV.
MATERIAL AND METHODS: A search for relevant articles published up to November 2019 was performed in PubMed/Medline and Cochrane databases, Clinicaltrials.gov, and Google Scholar. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adopted for the conduct of the systematic review. The most pertinent data were extracted and pooled for qualitative and quantitative analyses with 95% confidence intervals. Heterogeneity was analyzed by using I-squared statistics.
RESULTS: A total of 8 studies involving 411 individuals with HIV and 1109 implants were included in the meta-analysis. The mean follow-up period was 2.8 years. A pooled estimate of 95% of implant survival rate with 95% confidence interval(92% to 96%) was noted. Heterogeneity across the 8 studies was found to be 41% with moderate true variability.
CONCLUSIONS: This systematic review demonstrated that HIV infection does not pose a serious threat to implant survival on short-term evaluation, but the evidence is of low quality.
MATERIALS AND METHODS: An auricular prosthesis, a complete denture, and anterior and posterior crowns were constructed using conventional methods and laser scanned to create computerized 3D meshes. The meshes were optimized independently by four computer-aided design software (Meshmixer, Meshlab, Blender, and SculptGL) to 100%, 90%, 75%, 50%, and 25% levels of original file size. Upon optimization, the following parameters were virtually evaluated and compared; mesh vertices, file size, mesh surface area (SA), mesh volume (V), interpoint discrepancies (geometric similarity based on virtual point overlapping), and spatial similarity (volumetric similarity based on shape overlapping). The influence of software and optimization on surface area and volume of each prosthesis was evaluated independently using multiple linear regression.
RESULTS: There were clear observable differences in vertices, file size, surface area, and volume. The choice of software significantly influenced the overall virtual parameters of auricular prosthesis [SA: F(4,15) = 12.93, R2 = 0.67, p < 0.001. V: F(4,15) = 9.33, R2 = 0.64, p < 0.001] and complete denture [SA: F(4,15) = 10.81, R2 = 0.67, p < 0.001. V: F(4,15) = 3.50, R2 = 0.34, p = 0.030] across optimization levels. Interpoint discrepancies were however limited to <0.1mm and volumetric similarity was >97%.
CONCLUSION: Open-source mesh optimization of smaller dental prostheses in this study produced minimal loss of geometric and volumetric details. SculptGL models were most influenced by the amount of optimization performed.
OBJECTIVES: The aim of the study was to evaluate the deviation of implant placement performed with a surgical guide fabricated by means of the rapid prototyping technique (the PolyJet™ technology).
MATERIAL AND METHODS: Twenty sheep mandibles were used in the study. Pre-surgical cone-beam computed tomography (CBCT) scans were acquired for the mandibles by using the Kodak 9000 3D cone-beam system. Two implants with dimensions of 4 mm in diameter and 10 mm in length were virtually planned on the 3D models of each mandible by using the Mimics software, v. 16.0. Twenty surgical guides were designed and printed using the PolyJet technology. A total of 40 implants were placed using the surgical guides, 1 on each side of the mandible (2 implants per mandible). The post-surgical CBCT scans of the mandibles were performed and superimposed on the pre-surgical CBCT scans. The amount of deviation between the virtually planned placement and the actual implant placement was measured, and a descriptive analysis was done.
RESULTS: The results showed that the mean deviation at the implant coronal position was 1.82 ±0.74 mm, the mean deviation at the implant apex was 1.54 ±0.88 mm, the mean depth deviation was 0.44 ±0.32 mm, and the mean angular deviation was 3.01 ±1.98°.
CONCLUSIONS: The deviation of dental implant placement performed with a 3D-printed surgical guide (the PolyJet technology) is within the acceptable 2-millimeter limit reported in the literature.
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.
METHODS: Selected T2DM participants with peri-implantitis were distributed into 3 groups: Group-1: received a single session of adjunctive (aPDT); Group-2: received a single session of adjunctive (aAGT) (metronidazole 400 mg and amoxicillin 500 mg); and Group-3: received MD alone. Clinical (probing depth [PD], bleeding on probing [BOP], and plaque scores [PS]) and radiographic (crestal bone loss [CBL]) peri-implant variables were recorded. Levels of interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) were assessed after the collection of peri-implant sulcular fluid (PISF). All the evaluations were carried out at baseline, 3- and 6-months. The significance level was set to p < 0.05.
RESULTS: At 3-and 6-months of follow-up, all the three groups showed significant alleviation in PS (p < 0.05), BOP (p < 0.05), and PD (p < 0.05) when compared with the baseline. At baseline, no significant variation was observed in all clinical and radiographic peri-implant parameters among all three research groups. At 3-months follow-up, a considerable alleviation of in PS, BOP, PD, and CBL was noticeable in group-1 patients when compared with the baseline. At 6-months follow-up, a comparable difference was observed in BOP, PD, and CBL between group-1 and group-2. At baseline, no significant variation was observed in the PISF levels of IL-6 and TNF-α among all three research groups. At 3- and 6-months follow-up, a considerable alleviation of TNF-α and IL-6 levels was observed in group-1 and group-2 patients, respectively, when compared with the baseline.
CONCLUSION: The application of aPDT demonstrated improved clinical, radiographic, and immunological peri-implant parameters for the treatment of peri-implantitis among T2DM patients.
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