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The International Journal of Oral &... 2021To examine the effect of the attachment features (abutment height, retention, and freedom of rotation) of implant overdentures on the bending strain around implants...
PURPOSE
To examine the effect of the attachment features (abutment height, retention, and freedom of rotation) of implant overdentures on the bending strain around implants under an overdenture.
MATERIALS AND METHODS
Mandibular and maxillary edentulous models were fabricated and covered with silicone rubber. Strain gauges were attached to the four sides of each implant. Two implants (tissue-level implant, 4.1-mm diameter, 10-mm length) were placed bilaterally in the area between the mandibular canines and lateral incisors. A maxillary conventional denture and a mandibular overdenture were made to fit the edentulous models. Three levels of peri-implant bone resorption were created sequentially: no bone resorption, 0.8 mm, and 1.5 mm. Three kinds of attachments (magnetic, stud, and ball attachments) were used. Bending strains generated from a 98-N occlusal load through the maxillary denture were measured using a sensor interface, and the data were analyzed using the Kruskal-Wallis and Bonferroni tests. Multiple regression analysis was used to find the relationship between independent variables (peri-implant bone resorption level, abutment height, retention, and freedom of rotation) and the dependent variable (bending strain).
RESULTS
For all attachment types, the bending strains were smallest with no bone resorption and largest with 1.5-mm bone resorption (P < .05). Multiple regression analysis showed that abutment height had the greatest impact on the reduction of bending strain (beta = .413), followed by freedom of rotation (beta = -.349), and retention (beta = .107).
CONCLUSION
Low abutment height, large freedom of rotation, and low retention can minimize bending strain around implants.
Topics: Dental Implants; Dental Prosthesis, Implant-Supported; Denture Retention; Denture, Overlay; Mandible
PubMed: 33600528
DOI: 10.11607/jomi.8420 -
Acta of Bioengineering and Biomechanics 2020The purpose of this study was to compare the biomechanical behavior of the custom-made mandibular condyle prosthesis and total TMJ prosthesis.
PURPOSE
The purpose of this study was to compare the biomechanical behavior of the custom-made mandibular condyle prosthesis and total TMJ prosthesis.
METHODS
Three models of one beagle dog, the condyle prosthesis (Model 1, replacing the right condyle only), the TMJ prosthesis (model 2, replacing the whole right TMJ) and the intact TMJ (model 3) were established, and the mechanical responses under muscle forces loading were analyzed using finite element method.
RESULTS
Models 1 and 3 had the similar stress distribution on the right disc, which suggested that the condyle prosthesis did not change the disc stress so much when the muscle forces were applied. The stress of the right TMJ prosthesis in Model 2 was larger than both Models 1 and 3, and the stress of the contralateral TMJ reduced by 12% in Model 2. The anterior border of the condyle seemed to be a stress concentration region, not only for the intact condyle, but also for the condyle prosthesis and the total TMJ prosthesis.
CONCLUSIONS
The total TMJ prosthesis changed the biomechanical balance of the bilateral TMJ. When the condyle prosthesis iss applied, the custom-made profile is recommended.
PubMed: 34846022
DOI: No ID Found -
The Journal of Prosthetic Dentistry Aug 2023The medium-term effect of an implant-retained mandibular overdenture on bone remodeling in the maxilla and posterior mandible of edentulous patients and the effects on... (Observational Study)
Observational Study
STATEMENT OF PROBLEM
The medium-term effect of an implant-retained mandibular overdenture on bone remodeling in the maxilla and posterior mandible of edentulous patients and the effects on quality of life have not been established.
PURPOSE
The purpose of this prospective observational clinical study was to evaluate the 3-year effects of implant-retained mandibular overdentures on oral-health-related quality of life (OHRQoL) and bone remodeling in different regions of the maxilla and mandible in participants with atrophic or nonatrophic mandibles.
MATERIAL AND METHODS
Twenty-six edentulous participants received 2 narrow-diameter implants in the anterior mandible. Mandibular bone atrophy was categorized from presurgical panoramic radiographs according to the Cawood and Howell criteria. OHRQoL was assessed by using the OHIP-EDENT questionnaire. Participants were evaluated annually for 3 years to measure the marginal bone loss and bone area of the posterior mandible, and the anterior and posterior regions of the maxilla were assessed annually through panoramic radiographs. The data were analyzed by using a mixed-effects linear regression to estimate time-dependent trends and a mixed-effect linear regression model to verify differences between groups. The Pearson correlation coefficients between bone variables and 3-year OHIP-EDENT outcomes were calculated.
RESULTS
In the third year, atrophic participants had a significantly lower marginal bone loss (0.02 mm) than nonatrophic participants (-0.39 mm) (P=.030). Differences were also found in the functional limitation (nonatrophic=1.82 ±1.75, atrophic participants=1.92 ±1.54; P=.018) and handicap domains (nonatrophic=0.36 ±0.54, atrophic participants=0.08 ±0.27; P=.003). For nonatrophic participants, comparisons between baseline and 3-year outcomes showed significant bone resorption as indicated by the area ratio in the anterior maxilla (P=.035), posterior maxilla (P=.022), and posterior mandible (P=.009). Conversely, the bone area of the anterior maxilla (P=.019) decreased in atrophic participants between baseline and year 1, while the bone area of the anterior maxilla and posterior mandible increased (P<.001) between years 1 and 3. Higher effect sizes were observed in the OHRQoL domains of the atrophic participants.
CONCLUSIONS
Bone atrophy influenced both the OHRQoL profile and bone remodeling profile in different regions of the mandible and maxilla in mandibular overdenture users. In atrophic participants, bone tissue in both jaws responded positively to overdenture use, with bone apposition after the first year and bone area preservation in the anterior maxilla, posterior mandible, and peri-implant regions after 3 years of follow-up.
Topics: Humans; Denture, Overlay; Maxilla; Quality of Life; Bone Resorption; Mandible; Atrophy; Dental Prosthesis, Implant-Supported; Dental Implants; Jaw, Edentulous
PubMed: 34728072
DOI: 10.1016/j.prosdent.2021.08.019 -
The Journal of Craniofacial Surgery 2020The "Jaw in a Day" (JIAD) technique, first described by Levine and colleagues, establishes immediate functional occlusion through a single-stage maxillomandibular...
The "Jaw in a Day" (JIAD) technique, first described by Levine and colleagues, establishes immediate functional occlusion through a single-stage maxillomandibular reconstruction with concurrent implant placement and provisional prosthesis delivery. In this study, the authors describe 2 cases exemplifying the reconstructive principles of JIAD. One patient underwent mandibular reconstruction with the JIAD technique and another patient underwent JIAD with an optimized rapid sequence computer-aided design and computer-aided manufacturing (CAD-CAM) for composite maxillomandibular reconstruction. Immediate implant-borne prosthesis was fixated and all implants osseointegrated into the neomandible. Although the authors' patient outcomes are consistent with the literature, the published reports of JIAD remain limited, and further studies are required to assess the long-term functional and aesthetic outcomes as well as cost-effectiveness of this approach.
Topics: Computer-Aided Design; Female; Humans; Jaw; Male; Middle Aged; Orthognathic Surgical Procedures; Prosthesis Implantation
PubMed: 32224781
DOI: 10.1097/SCS.0000000000006369 -
Journal of Biomedical Materials... Jun 2022The wear of a novel temporomandibular joint (TMJ) prosthesis was evaluated in an animal model. The prosthesis consisted of an additively manufactured titanium alloy (Ti...
The wear of a novel temporomandibular joint (TMJ) prosthesis was evaluated in an animal model. The prosthesis consisted of an additively manufactured titanium alloy (Ti Al V) mandibular condyle and glenoid fossa created through selective laser melting, with a machined vitamin E-enriched ultra-high molecular weight polyethylene (UHMWPE) surface attached to the fossa. Thirteen TMJ prosthesis were implanted in sheep, six of which had condylar heads coated with HadSat® diamond-like carbon (H-DLC). Euthanasia took place after 288 days, equaling 22 years of human mastication. Linear and volumetric wear analysis of the fossa was performed by optical scanning. The condylar head surfaces were assessed by scanning electron and confocal laser microscopy. The average linear UHMWPE wear, when combined with the coated condyle, was 0.67 ± 0.28 mm (range: 0.34-1.15 mm), not significantly differing (p = .3765, t-test) from the non-coated combination average (0.88 ± 0.41 mm; range: 0.28-1.48 mm). The respective mean volumetric wear volumes were 25.29 ± 11.43 mm and 45.85 ± 22.01 mm , not significantly differing (p = .1448, t-test). Analysis of the coated condylar surface produced a mean Ra of 0.12 ± 0.04 μm and Sa of 0.69 ± 0.07 μm. The non-coated condylar surface measured a mean Ra of 0.28 ± 0.17 μm and Sa of 2.40 ± 2.08 μm. Both Sa (p = .0083, Mann-Whitney U test) and Ra (p = .0182, Mann-Whitney U test), differed significantly. The prosthesis exhibits acceptable wear resistance and addition of the H-DLC-coating significantly improved long-term condylar surface smoothness.
Topics: Alloys; Animals; Hip Prosthesis; Joint Prosthesis; Mandibular Condyle; Prosthesis Design; Prosthesis Failure; Sheep; Temporomandibular Joint; Titanium
PubMed: 35088936
DOI: 10.1002/jbm.b.35010 -
The International Journal of Oral &... 2021This study aimed to test the effectiveness and reliability of the alveolar ridge-splitting technique in atrophic posterior arches, investigating the middle-term...
PURPOSE
This study aimed to test the effectiveness and reliability of the alveolar ridge-splitting technique in atrophic posterior arches, investigating the middle-term volumetric and clinical outcomes.
MATERIALS AND METHODS
Atrophic alveolar ridges in the maxillary and mandibular posterior areas were treated with the alveolar ridge-splitting/expansion technique (ARST), immediate implant placement, collagen sponges covering the defect, and healing by secondary intention. Areas were rehabilitated by fixed dental prostheses supported by dental implants. Changes in volume and width of the alveolar ridge were retrospectively calculated by comparing the x-ray tomography scans obtained before and 5 years after surgery. Report of failure in the case sheets was taken into account. Cross-sectional images were also used to assess the thickness of the labial alveolar plates at the implant shoulder. Nonparametric analyses of variance with post hoc and pair-comparison tests were performed with a level of significance of .05.
RESULTS
A total of 38 patients were retrospectively selected (23 women and 15 men). Six patients underwent ARST surgeries in both the maxilla and the mandible and were excluded from statistical analysis. Differences between 16 maxillae and 16 mandibles and between 12 single crowns and 20 fixed partial dentures (FPDs) were searched. Episodes of minor swelling occurred within the first 2 days after surgery. Neither mucositis nor flap dehiscence had been registered. The mean values of buccal cortical thickness were 2.46 ± 0.49 mm and 1.15 ± 0.33 mm, respectively, in the maxillary and mandibular areas. After 5 years of survey, maxillary increases in alveolar ridge width and volume were +4.4 ± 0.4 mm and +295 ± 45 mm, respectively, whereas the same outcome variables (+3.5 ± 0.7 mm and +217 ± 53 mm) measured in the mandible appeared to be significantly smaller than those in the maxilla (P < .0001). One maxillary single implant failed. Cumulative survival rates at 5 years were 100% for mandibles and 95.5% (95% CI: 86.8% to 100%) for maxillae.
CONCLUSION
Posterior areas of the maxilla displayed a higher increase in alveolar width and volume than mandibular areas, and even if it would be premature to draw survival conclusions at this stage without any statistical support, a lower cumulative survival rate was reported for the maxillary single implants.
Topics: Alveolar Bone Loss; Alveolar Ridge Augmentation; Dental Implantation, Endosseous; Dental Implants; Dental Prosthesis Design; Dental Prosthesis, Implant-Supported; Dental Restoration Failure; Female; Humans; Male; Mandible; Maxilla; Reproducibility of Results; Retrospective Studies
PubMed: 34698727
DOI: 10.11607/jomi.8572 -
International Journal of Oral and... Dec 2022Medical device embodiment involves the following elements: materials, design, and manufacturing. Failure of any one of these elements can result in failure of the... (Review)
Review
Medical device embodiment involves the following elements: materials, design, and manufacturing. Failure of any one of these elements can result in failure of the device, despite the others being satisfactory. The abundance of clinical and basic science literature published since 1986, demonstrates the safety and efficacy of alloplastic temporomandibular joint replacement (TMJR). Currently, there are 19 countries producing 41 TMJR devices. More than 75% are custom designed, and 27% are additively manufactured. In light of the increasing number of TMJR devices being designed and manufactured around the world, this paper will discuss TMJR embodiment so that clinicians understand their present status as well as the prospects for the future of new and/or improved TMJR devices, to ensure that these devices continue to be safe and effective long-term surgical options for the management of end-stage TMJ pathologies.
Topics: Humans; Temporomandibular Joint; Joint Prosthesis; Mandibular Prosthesis
PubMed: 35717278
DOI: 10.1016/j.ijom.2022.05.015 -
The International Journal of...To evaluate the current literature and provide clinical recommendations related to the number of implants, implant characteristics, loading protocols, survival rates,...
PURPOSE
To evaluate the current literature and provide clinical recommendations related to the number of implants, implant characteristics, loading protocols, survival rates, biologic and mechanical complications, patient satisfaction, and financial considerations for mandibular implant-supported full-arch prostheses.
MATERIALS AND METHODS
A PubMed/MEDLINE search for literature published between January 1, 1980 and February 8, 2019, was performed for systematic reviews on this topic. The PICO question was: In mandibular fully edentulous patients treated with implant full-arch prostheses, is there any difference between fixed and removable implant prostheses in terms of implant and prosthesis survival rates? Only systematic reviews with or without meta-analyses were included. The findings varied based on the type of implant full-arch prosthesis.
RESULTS
High survival rates for implants and prostheses have been reported for fixed and removable implant full-arch prostheses in the mandible. Immediate loading procedures present with high survival rates for both fixed and removable prostheses. There are differences in the number of implants, implant characteristics, complications, and financial implications between these two types of prostheses, which clinicians need to account for as part of the treatment planning process.
CONCLUSION
Implant-supported overdentures and implant-supported fixed complete dentures represent clinically successful treatment approaches. In cases where both treatment options are indicated, patient expectations and cost should be the determining factors for selecting a treatment modality.
Topics: Dental Implants; Dental Prosthesis, Implant-Supported; Denture, Complete; Denture, Overlay; Follow-Up Studies; Humans; Mandible; Treatment Outcome
PubMed: 33571328
DOI: 10.11607/ijp.6911 -
Clinical Oral Implants Research Mar 2022This prospective study aimed to assess the effectiveness of using a single short implant to retain a single-implant mandibular overdenture (SIMO) in participants with...
OBJECTIVE
This prospective study aimed to assess the effectiveness of using a single short implant to retain a single-implant mandibular overdenture (SIMO) in participants with severely atrophic edentulous mandibles.
MATERIAL AND METHODS
The study sample included 18 edentulous participants with severely resorbed mandibular ridges and limited bone height in the symphyseal region sufficient for the insertion of a 7.0-mm-height implant. First, patients received new conventional dentures or had their dentures relined, followed by the insertion of a 3.75 x 7 mm morse-taper implant, and the incorporation of a stud-type attachment and a nylon retentive insert after a 3-month healing period. Implant stability quotient (ISQ) was measured at baseline and after 3 and 12 months. Patient-reported outcomes (satisfaction with the dentures and oral health-related quality of life) were assessed before implant placement and at the 3-, 6-, and 12-month follow-ups. Clinical-radiographic outcomes and the incidence of prosthodontic events were assessed throughout the follow-up period.
RESULTS
The implant survival rate was 100%. ISQ increased from baseline (72.7 ± 6.6) to the 3-month (82.0 ± 3.3) and 1-year (85.4 ± 2.9) follow-ups (p < .001). After 1 year, satisfaction with the mandibular prosthesis increased significantly, and the overall OHIP-Edent score decreased by 79.2%. No effects were found for the maxillary denture (p = .420). Due to dissatisfaction with treatment, two participants (11.1%) required additional implants after the 1-year follow-up and were considered as prosthodontic failures.
CONCLUSION
Single-implant mandibular overdenture retained by a short implant showed favorable outcomes after 1 year. Further studies with larger samples and longer follow-up periods are needed to confirm the findings of this single-group prospective study. The present study was registered at the Brazilian Clinical Trials Registry (REBEC), identifier RBR-7p2xmg. The trial registry occurred during the study execution, and its final approval was delayed because of several formatting adequacies required by the platform REBEC.
Topics: Dental Implants; Dental Prosthesis, Implant-Supported; Denture Retention; Denture, Overlay; Humans; Mandible; Patient Satisfaction; Prospective Studies; Quality of Life; Treatment Outcome
PubMed: 34951501
DOI: 10.1111/clr.13887 -
The International Journal of Oral &... 2022This study aimed to evaluate clinical and prosthetic outcomes of metal-ceramic and polyether ether ketone (PEEK) fixed prostheses supported by four maxillary implants...
Metal-Ceramic and Polyether Ether Ketone-Composite Maxillary Fixed Prosthesis Supported by Four Implants and Opposed by Removable Distal Extension Partial Dentures: A Comparative Study of Clinical and Prosthetic Outcomes.
PURPOSE
This study aimed to evaluate clinical and prosthetic outcomes of metal-ceramic and polyether ether ketone (PEEK) fixed prostheses supported by four maxillary implants and opposed by distal extension removable partial dentures.
MATERIALS AND METHODS
Thirty participants with edentulous maxillary and distal extension mandibular ridges received four implants according to the All-on-4 treatment concept. The implants were immediately loaded by fixed acrylic prostheses. After 6 months, patients received either metal frameworks covered with porcelain teeth (metal group) or PEEK framework veneered with composite teeth (PEEK group). Plaque Index (PI), Gingival Index (GI), pocket depth (PD), implant stability quotient (ISQ), peri-implant marginal bone loss (MBL, using digital periapical radiographs), and implant survival were measured at baseline, 1 year, and 3 years. Prosthetic complications were measured on the patient and implant levels after 3 years.
RESULTS
No implant failures occurred after insertion of the definitive prosthesis, and the implant survival rate was 100% in both groups. PI, GI, PD, ISQ, and MBL increased significantly with time. The most frequent complications were veneer fracture for the PEEK group and prosthetic screw loosening for the metal group. The metal group showed significantly higher PI, PD, and MBL than the PEEK group after 3 years. PEEK was associated with significantly higher veneer fracture than metal, while metal was associated with significantly higher prosthetic screw loosening than PEEK.
CONCLUSION
Within the limitations of this study, the PEEK framework veneered with composite may be a suitable alternative to a metal porcelain prosthesis for All-on-4 implant rehabilitation in patients with maxillary edentulous arches opposed by distal extension mandibular ridges, as it was associated with favorable clinical and prosthetic outcomes after 3 years. However, it was associated with an increased rate of veneer or artificial gingiva fracture.
Topics: Benzophenones; Ceramics; Dental Implants; Dental Prosthesis, Implant-Supported; Denture, Partial, Removable; Ethers; Humans; Ketones; Polymers; Treatment Outcome
PubMed: 35235637
DOI: 10.11607/jomi.9189