Is there a certain number of implants needed to retain an overdenture?

Comparison of Implant-Retained Overdenture and Conventional Complete Denture: A Survey Study to Measure Patients' Satisfaction and Quality of Life in Dental School Clinics

Patient satisfaction and quality of life are integral to assessing oral health care quality. For many Americans still using conventional complete dentures (CDs) or implant-retained mandibular overdentures (IODs), it remains essential to consider improving their oral health outcomes and quality of life. Due to inexperienced student dentists providing dental care to dental school patients, patient grievances are generally considered a problem. Patient feedback and satisfaction have proven valuable resources for monitoring and improving patient safety. While CDs and IODs are the 2 leading treatment options for edentulism, more comparative studies in the literature need to compare their outcomes in a school setting. The research question that guided this comparative analysis was, "Is patient satisfaction and quality of life affected by the type of prostheses and provider?" A validated questionnaire was mailed to 520 individuals selected from records of patients who had received treatment for edentulous mandible at a student prosthodontic clinic at the University of Kentucky College of Dentistry from 2014 to 2016 with at least 1 year of follow-up time. A validated questionnaire for edentulous patients based on the Oral Health Impact Profile (OHIP-19) was used. In addition, information on patients' oral health-related quality of life, including questions related to the edentulous patients' satisfaction with their dentures, was collected. The response rate was 33% (N = 171). The study's findings confirm previous findings, suggesting that IODs may significantly impact oral health-related quality of life. Data show that 76% of the IOD group reported improvement in experience when using the implants to retain the mandibular denture. However, there were no statistically significant differences in the OHIP scores between overall CD and IOD patient groups. Males with IODs had lower physical pain, limitations, and disability scores than males with CD. However, females with IODs reported more significant concerns associated with a social disability and handicap domains. Comparing users who had experiences with both treatment options, this study discerned essential characteristics that contribute to increased patient satisfaction with IODs and identified significance in outcomes by gender. These findings guide prosthodontic practitioners' patient care practices and identify a continuing need to discuss CD and IOD treatment protocols within dental school curricula.

In vitro measurement of the retention force of two stud attachment systems during cyclic load

PURPOSE

To investigate the retentive behavior of the Locator legacy and Novaloc attachment systems with different retention inserts both within and across systems under cyclic load.

MATERIALS AND METHODS

Three retention inserts of each system (green, yellow, and white for Novaloc; green, orange, and red inserts for extended range for legacy Locator) were tested on abutments of both systems with a sample number of 10 per force and 10,000 cycles of insertion and removal. The loading was applied in the axial direction of the abutments, which were placed in artificial saliva. The retention force was measured in each cycle. The results were compared with the manufacturer's specifications and evaluated for a simulated period of use of 10 years. Characteristic time constants were determined, and subsequently, the two systems were compared regarding their wear behavior.

RESULTS

The manufacturer's specifications could only be confirmed for the green Novaloc retention insert on a Novaloc abutment (t-test: p = 0.50); for all other inserts, the baseline exceeded the manufacturer's specifications by 30%-75% (Novaloc; t-test: p < 0.001) and 75%-550% (Locator; t-test: p < 0.001). After 10,000 cycles performed, the manufacturer's specifications were confirmed on a Novaloc abutment for the white Novaloc retention insert (t-test: p = 0.86) and on a Locator abutment for the green Novaloc retention insert (t-test: p = 0.32). Both systems lost retention force during the experiment. Overall, Novaloc inserts on both abutments showed less wear (decrease to 56%-85% of initial force) and a slower decrease in retention force compared to Locator inserts (decrease to 6%-31% of initial force).

CONCLUSIONS

In both systems, wear leads to a varying loss of retention; therefore, regular checks with possible replacement of the inserts are necessary in clinical use. Novaloc attachments seem to be more resistant to the loss of retention than Locator attachments. A cross-combination may be clinically useful in some cases.

Bibliometric assessment in implant-retained overdenture articles: Mapping citation and journal impact factor trends

STATEMENT OF PROBLEM

Implant-retained overdentures are a recognized treatment option. However, a comprehensive assessment of all articles on implant-retained overdentures to identify publication standards such as mean citation and the Journal Citation Reports (JCR) impact factor is lacking.

PURPOSE

The purpose of this bibliometric assessment was to evaluate the association of mean citation and JCR impact factor with bibliometric parameters in articles on implant-retained overdentures.

MATERIAL AND METHODS

Articles reporting randomized controlled clinical trials (RCTs) and nonrandomized controlled clinical trials (N-RCTs); case reports and series; retrospective studies; and in silico, in vitro, or systematic reviews in 6 databases were included. Data were extracted, and 2 multiple Poisson regressions analyses were applied (α=.05). The dependent variables were mean citation and JCR impact factor, which were evaluated to identify their association with bibliometric parameters by using prevalence ratio (PR) values.

RESULTS

A total of 1369 articles published from 1986 to 2021 were included. The data revealed a high mean citation and high JCR impact factor for RCT, N-RCT, retrospective, and in vitro studies (P<.05). In silico studies presented a high mean citation (P<.001). Senior researchers with a high h-index were more likely to have a high mean citation and publications with a high JCR impact factor (P<.001). Also, senior authors associated with an international network were more likely to have a high mean citation (P=.001). High-income countries had more studies with a high mean citation and JCR impact factor (P<.05). Higher JCR impact factors were associated with articles evaluating only the maxilla or mandible (P<.05). The topics "implant setting" and "macrodesign" were associated with a high mean citation (P<.05).

CONCLUSIONS

The publication trends suggest a high mean citation and a high JCR impact factor for clinical designs (RCT, N-RCT, retrospective) and in vitro studies. The same pattern was also displayed for researchers with a high h-index and located in high-income countries.

Mandibular 3-implant overdenture: A clinical report of a novel design

OBJECTIVE

To report on the use of a mandibular 3-implant overdenture with a novel implant distribution opposing a maxillary complete denture for the rehabilitation of an older edentulous patient.

BACKGROUND

The use of oral implants with attachment systems of various numbers and designs to support removable partial and complete dentures is well documented with success and predictability.

MATERIALS AND METHODS

An older edentulous patient with a mandibular implant-assisted removable partial denture was presented with failing remaining dentition. Teeth were extracted and a single midsymphyseal implant was placed. A mandibular overdenture on three implants with ball attachments in a tripod distribution was constructed to oppose a new maxillary complete denture made using a modified impression technique.

RESULTS

Over 2 years of follow-up, no significant biological or mechanical complications were reported, and denture retention and stability remained optimum.

CONCLUSION

Mandibular overdentures on three implants with ball attachments in a tripod distribution, opposing a maxillary complete denture, could be an alternative treatment option for the older edentulous patients.

Peri-Implant Bone Loss and Overload: A Systematic Review Focusing on Occlusal Analysis through Digital and Analogic Methods

The present review aimed to assess the possible relationship between occlusal overload and peri-implant bone loss. In accordance with the PRISMA guidelines, the MEDLINE, Scopus, and Cochrane databases were searched from January 1985 up to and including December 2021. The search strategy applied was: (dental OR oral) AND implants AND (overload OR excessive load OR occlusal wear) AND (bone loss OR peri-implantitis OR failure). Clinical studies that reported quantitative analysis of occlusal loads through digital contacts and/or occlusal wear were included. The studies were screened for eligibility by two independent reviewers. The quality of the included studies was assessed using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool. In total, 492 studies were identified in the search during the initial screening. Of those, 84 were subjected to full-text evaluation, and 7 fulfilled the inclusion criteria (4 cohort studies, 2 cross-sectional, and 1 case-control). Only one study used a digital device to assess excessive occlusal forces. Four out of seven studies reported a positive correlation between the overload and the crestal bone loss. All of the included studies had moderate to serious overall risk of bias, according to the ROBINS-I tool. In conclusion, the reported data relating the occlusal analysis to the peri-implant bone level seem to reveal an association, which must be further investigated using new digital tools that can help to standardize the methodology.

Effect of Various Retentive Element Materials on Retention of Mandibular Implant-Retained Overdentures

This study aimed to examine the retentive characteristics of each retentive element material and the effects from thermocycling using the two implant-retained mandibular overdenture model. Two stud abutments and three retentive element materials; nylon, polyetheretherketone (PEEK) and polyvinylsiloxane (PVS) were used in this study. Four tested groups, with a total of 40 overdentures, were fabricated, including a Locator® abutment with nylon retention insert (NY), Novaloc® abutment with PEEK retention insert (PK), Locator® abutment with PVS retention insert (RL), and Novaloc® abutment with PVS retention insert (RN). The retentive force (N) was measured before thermocycling, and at 2500, 5000, and 10,000 cycles after thermocycling. Significant changes in the percentage of retention loss were found in the NY and PK groups (p < 0.05) at 6 and 12 months for the RL group (p < 0.05) after artificial aging. The RN group exhibited a constant retentive force (p > 0.05). The tendency of the percentage of retention loss significantly increased for PEEK, nylon, and PVS silicone over time. The results of the present study implied that retentive element materials tend to lose their retentive capability as a result of thermal undulation and water dispersion. Nylon and PEEK, comprising strong polar groups in polymer chains, showed a higher rate of retention loss than polyvinylsiloxane.

Comparative clinical study of conventional dental implant and mini dental implant-retained mandibular overdenture: A 5- to 8-Year prospective clinical outcomes in a previous randomized clinical trial

AIM

To compare the long-term prospective clinical outcomes in a previous randomized controlled clinical trial (RCT) of 2 Mini Dental Implant (2MDI), 4 Mini Dental Implant (4MDI), and 2 Conventional Dental Implant (2CDI)-retained mandibular overdenture with follow-up between 5 to 8 years.

MATERIALS AND METHODS

Thirty-seven patients formerly participated in the Comparative Clinical Study of CDI and MDI for Mandibular Overdenture were requested for examination of clinical outcomes. A total of 104 implants were placed with mean follow-up periods 6.64 ± 0.60 years. In Group 1 (2MDI) and Group 2 (4MDI), implants were placed and immediately loaded with Equator® attachments to retained mandibular overdenture. In Group 3 (2CDI), implants were placed and delayed 3 months for denture loading with ball attachment. The success rate, survival rate, clinical implant performance scale (CIP scale), peri-implant tissue status, prosthetic complication, implant stability quotient (ISQ), marginal bone level change (MBLC), and patient satisfactions were analyzed.

RESULTS

After 5 to 8 years follow-up, the success rate in Groups 1, 2, and 3 were 90.91%, 93.33%, and 54.55%, respectively. The success rate in Group 3 was significantly lesser than Group 1 (p = 0.016) and Group 2 (p < 0.001). The survival rate in Groups 1, 2, and 3 was 100%, 96.67%, and 90.91%, respectively, and showed no significant differences. Mean ISQ reported no significant differences between groups. Mean MBLC were 0.57 ± 1.19 mm, 0.68 ± 0.90 mm, and 1.55 ± 1.60 mm in Groups 1, 2, and 3, respectively. Group 3 reported significantly greater mean MBLC than Group 1 (p = 0.016) and Group 2 (p = 0.011), but Groups 1 and 2 were not significantly differences. The overall patient satisfactions were reported as not significant differences between groups.

CONCLUDE

Two MDI-retained mandibular overdentures with immediate loaded protocol performed had favorable clinical outcomes, cost effectiveness, and overall patient satisfactions after 5 to 8 years follow-up.

Case Series on the Long-Term Effect of Three Different Types of Maxillary Implant-Supported Overdentures on Clinical Outcomes and Complications

(1) Long-term data on maxillary implant overdentures (IODs) are scarce. This case series evaluated three types of IODs supported by six, four or three implants (Anyridge^®, Mega'Gen Implant Co., Ltd., Daegu, South-Korea), after 3-5 years in function. (2) A total of 31 patients, with 132 implants, were non-randomly allocated based on available bone or financial limitations. IOD-6 received a telescopic overdenture; IOD-4 a bar; and IOD-3, non-connected implants with locator abutments. Implant survival, bone level changes, probing pocket depth (PPD), plaque index, bleeding on probing (BOP), and technical, biological and aesthetic complications were registered. Impact of suprastructures on bone loss and PPD was analyzed using mixed-effect linear regression models. Differences between groups were analyzed using the ANOVA test for BOP, and Kruskal Wallis test for complications. (3) In total, 23 patients participated in the follow-up (9 female, 14 male), with average age of 62.2 years; 7, 11 and 5 patients in IOD-6, IOD-4 and IOD-3, respectively. Implant survival after 4.4 years on average, was 98% in total; 100%, 97.8% and 93.3% for IOD-6, IOD-4 and IOD-3, respectively. Mean bone loss corresponded to 0.68 mm (SD 1.06, range -4.57-1.51), 0.39 mm (SD 1.06, range -3.6-2.43), and 1.42 mm (SD 1.68, range -5.11-0.74) for IOD-6, IOD-4 and IOD-3, respectively. A statistically significant difference was seen in bone level when comparing IOD-6 to IOD-3 (p = 0.044), and IOD-4 to IOD-3 (p = 0.018). Mean PPD was 3.8 mm (SD: 0.69; range 2.5-5.3), 3.5 mm (SD 0.59; range 2.33-5), and 3.2 mm (SD 0.56; range 2-4) for IOD-6, IOD-4 and IOD-3, respectively, and differed significantly between IOD-6 and IOD-3 (p = 0.029). Incidence of peri-implantitis was 1%. No differences were seen for complications between groups. (4) Maxillary IOD supported by four to six implants is the most reliable treatment regarding implant survival and peri-implant health. More research is needed in the clinical outcomes, in particular the peri-implant health, and complications of maxillary IODs, especially with a reduced number of implants.

How successful are maxillary implant-retained overdentures on two or four implants?

Design A randomised crossover clinical trial was designed to determine survival and success of four-implant overdentures in the edentulous maxilla, in participants with mandibular two-implant overdentures. Participants received four implants in the maxilla, two anteriorly and two posteriorly, then were randomly allocated into two treatment groups. The prosthetic phase included alternate loading of anterior and posterior implants for three months each, followed by loading of all four implants for another three months. Participants were then followed up in the recall phase for a mean period of 2.2 years.Case selection Four participants were taken from the authors' previous clinical study, meeting the inclusion criteria for a two-implant overdenture in the mandible. Another 21 participants were recruited from study calls after a widening of inclusion criteria. These patients were all pre-treated in accordance with the previous study protocol, so there was standardisation before maxillary implant placement.Data analysis A sample size calculation was performed and a Kaplan-Meier curve was used to demonstrate implant survival over time.Results Twenty-four patients were included in the study. Three implants were lost during the prosthetic phase and two during the recall phase; all were anterior implants. Implant survival after loading was 93.8% after a mean period of 3.1 years. There were 27 maxillary prosthetic complications overall. Denture success was 95.8% after a mean period of 2.2 years.Conclusions Implant survival of four asynchronously loaded implants in implant-supported overdentures in the edentulous maxilla was good and is a recommendable treatment option for patients with two-implant mandibular overdentures. Implant and prosthetic complications are common but mostly straightforward to manage. Two posterior implants are not superior to two anterior implants, but the majority of patients prefer the four-implant maxillary overdenture.

Masticatory efficiency in complete denture and single implant-retained mandibular overdenture wearers with different occlusion schemes: A randomized clinical trial

STATEMENT OF PROBLEM

How the masticatory function of complete denture wearers is influenced by the positioning and occlusion of posterior teeth or by the presence of a single mandibular implant is unclear.

PURPOSE

The purpose of this randomized crossover clinical trial was to evaluate the masticatory efficiency of wearers of bimaxillary complete dentures and of wearers of maxillary complete denture and single implant-retained mandibular overdentures, both with bilateral balanced occlusion and lingualized occlusion.

MATERIAL AND METHODS

Participants received 2 sets of complete dentures with interchangeable teeth in the mandibular prosthesis to allow a change in the occlusion scheme. Subsequently, 1 implant was placed in the mandibular symphysis region, and the mandibular complete dentures were converted to overdentures. The masticatory efficiency was measured by the sieve method for both occlusal schemes.

RESULTS

Repeated measures ANOVA showed no statistically significant difference in the masticatory efficiency with the 2 occlusal schemes for conventional complete dentures (P=.707) or overdentures (P=.407). When comparing the type of prosthesis, statistical differences were found for masticatory efficiency (P=.012), with improved mastication for the overdentures.

CONCLUSIONS

A mandibular single implant improved the masticatory efficiency of patients with complete dentures, but the occlusal scheme did not influence this factor.

Maxillary implant overdentures on two or four implants. A prospective randomized cross-over clinical trial of implant and denture success and survival

OBJECTIVES

To determine implant survival and success of four conventionally but initially asynchronously loaded implants in implant-supported overdentures for the edentulous maxilla, in participants with opposing mandibular two-implant overdentures.

MATERIAL AND METHODS

Twenty-six participants received four implants in the region of the maxillary canines and molars. After healing, 24 of these participants (mean age: 68.3 years) were randomly allocated to one of two treatment groups, and the adapted overdenture was attached to two unsplinted cylindrical attachments. The other two matrixes remained unattached to the implants for 3 months. After this period, the other two implants were loaded for 3 months (cross-over design). Then, all four implants were loaded for another 3 months. Kaplan-Meier curves were used to evaluate survival and success of implants and dentures.

RESULTS

During the active prosthetic study phase, three participants lost one implant. Two participants lost three implants during the recall period. Implant survival after loading was 93.8% after a mean observation period of 3.1 years. Denture survival was 100%, but denture success was 95.8%, due to major prosthetic complications. Most participants preferred four implants to two.

CONCLUSIONS

Within the limitations of the study, it can be concluded that maxillary implant overdentures on two or four implants are both recommendable treatment options. Two posterior implants are not superior to two anterior implants under overdentures retained by unsplinted cylindrical attachments. Implant and prosthetic complications and aftercare measures are common but are mostly easy to handle. However, 23 of the 24 participants preferred the 4-implant maxillary overdenture.

A 5-Year Retrospective Study Evaluating Periodontal Health and Oral Health-Related Quality of Life of Implant-Supported Overdentures With Locator and Magnetic Attachments

This study compared peri-implant vertical bone loss, the periodontal index, prosthodontic maintenance requirements and oral health-related quality of life (OHQoL) of patients using mandibular implant-supported overdentures with 2 different attachment systems after an average of 5 years of use. Sixteen mandibular overdenture patients with magnet attachments (group 3), 24 with implant-supported mandibular overdentures with Locator attachments (group 2), and 25 conventional complete denture patients (group 1) were included in the study. The existing at least 5 years old dentures of all patients were evaluated for prosthodontic maintenance by the same prosthodontist and the patients were administered the oral health impact profile-14-Turkish version (OHIP-TR-14) questionnaire. Peri-implant tissue health was evaluated clinically in terms of plaque scores, bleeding scores, probing depth, and gingival index. Radiographic evaluation was performed in terms of peri-implant vertical bone loss. Radiographic evaluations were performed 5 years after overdenture insertion. There were no statistically significant differences between the groups in terms of total OHIP-TR-14 scores (P > .05). Although the average vertical bone resorption measured in group 2 at the end of 5 years was 1.38 mm, there was an average vertical bone loss of 1.45 mm in group 3, but this difference was not statistically significant (P > .05). Among the periodontal health indicators, there were no statistically significant differences in the mean values for periodontal indexes. According to results of the study, there were no differences in peri-implant vertical bone loss in groups 2 and 3, in periodontal health in mandibular overdentures with groups 2 and 3, or between total OHIP-TR-14 scores of patients in all groups.

Clinical and satisfaction outcomes of using one or two dental implants for mandibular overdentures: preliminary short-term follow-up of a randomized clinical trial

Objective

This randomized clinical trial aimed to evaluate the marginal bone loss and peri-implant aspects in patients with mandibular overdentures retained by one or two implants and assess patient satisfaction, prosthesis-related clinical outcomes, and masticatory efficiency.

Methods

Patients from the School of Dentistry of the University of Passo Fundo (UPF) with lower conventional complete dentures dissatisfied with prosthetic retention were selected. Eighteen patients were analyzed and divided into randomized treatment groups: GA, installation of one implant in the midline of the mandibular symphysis (8 patients), and GB, installation of two implants in the lower canine region (10 patients). Implant survival and prosthetic maintenance were assessed by clinical and radiographic examinations performed 6 months after implant placement and 3 months after loading. Finally, the masticatory efficiency of the prostheses was evaluated with the QoLIP-10 (Quality of Life with Implant-Prostheses) questionnaire, and the degree of patient satisfaction used the visual analog scale (VAS).

Results

Regarding the esthetic satisfaction of the patients, there was no statistical difference between the two groups studied (p = 0.680). Patients who received two implants presented easier chewing (p = 0.049) and a lower average number of prosthesis maintenance. There was no difference between the groups regarding peri-implant bone resorption 3 months after the use of prostheses.

Conclusions

The use of two dental implants showed higher masticatory ability and lower need for maintenance appointments when compared with one implant in mandibular overdentures but did not affect peri-implant aspects and patient satisfaction. The treatment using one implant was effective for the aspects evaluated, but further clinical studies are required on the subject.

A fixed reconstruction of fully edentulous patients with immediate function using an apically tapered implant design: a retrospective clinical study

Background

Immediate function has become an accepted treatment modality for fixed restorations in completely edentulous jaws. It is known that implant microtopography (surface) may enhance osseointegration, while implant macrotopography (macrodesign) plays an important role in primary stability in the patient requiring an immediate loading. The aim of this retrospective study was to evaluate the clinical and radiographic outcomes of the edentulous subjects treated with narrow and/or regular diameter, which placed and loaded immediately.

Methods

Forty-two consecutive patients received 171 implants, including regular and narrow diameter implants (NDIs). Each jaw, 19 mandibles and 24 maxillae, was treated with a fixed-full arch prosthesis according to the Straumann® Pro Arch concept. The majority (95%) of the restorations were supported by four implants, of which the posterior two implants were tilted. A provisional functional acrylic prosthesis was delivered on the day of surgery. All patients were followed up to 55 months. Cumulative survival rate was determined using Kaplan-Meier analysis. Radiological measurement of marginal bone level was performed.

Results

The overall follow-up time for survival rate was up to 55 months. Four implants (3 implants in maxilla, 1 implant in mandible) were lost, resulting in an overall cumulative implant survival rate of 97.7%. Implant survival rate in the axial and tilted implants was not statistically significant. The mean of interproximal marginal bone loss was 0.15 mm after 24 months. Good soft tissue health was observed in almost 99% of patients. The final prosthesis survival rate was 100%.

Conclusions

The results of this retrospective pilot study indicated that total edentulous patients requiring an immediate implant placement and loading can be successfully treated with this implant design. The improved mechanical properties of these implants might give a more conservative treatment option for the jaws showing a severe horizontal alveolar bone resorption.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40729-020-00271-1.

Do implant-retained mandibular overdentures maintain radiographic, functional, and patient-centered outcomes after 3 years of loading?

OBJECTIVES

Analyzing whether radiographic, functional, and oral health-related quality of life (OHRQoL) outcomes are maintained over 3 years of implant-retained mandibular overdenture (IMO) function and investigating the bite force associations in the 3rd year of function.

MATERIAL AND METHODS

A longitudinal clinical study in which 24 IMO users were evaluated during a 3-year follow-up period. Patients' posterior area index, masticatory function, OHRQoL and bite force were assessed. The masticatory function parameter ST_X50 reflects the opening through which 50% of the crushed particles would pass, ST_B describes the homogeneity of the bolus, and the masticatory efficiency parameters ME_5.6 and ME_2.8 represent the % of material retained in the 5.6 and 2.8 mm sieves, respectively.

RESULTS

A significant increase in posterior area index (p ≤ .01) was found in all evaluated periods. Minor deteriorations in ST_X50 (p ≤ .01) and ME_5.6 (p ≤ .01) between the 2nd and the 3rd year coincided with improvements in ST_B (p ≤ .01), number of cycles (p ≤ .01), and cycle time (p = .02). The global OHIP-Edent score (p = .02) and the scores in the functional limitation (p = .02), psychological discomfort (p ≤ .01), and handicap domains (p ≤ .01) increased significantly between the 2nd and the 3rd year. Correlations between bite force and cycle time (p = .03) and between posterior area index and ST_X50 (p ≤ .01) and ME_2.8 (p = .02) were also found.

CONCLUSION

Changes in posterior area index, masticatory function, and OHRQoL are still ongoing during the 3rd year of IMO function. Bite force and posterior area index influence the masticatory function outcomes in the 3rd year of IMO function.

Rehabilitation of an Extremely Edentulous Atrophic Maxilla with a Pseudoskeletal Class III Relationship

The skeletal class III relationship presents complex dentoalveolar problems, requiring multidisciplinary treatment. In edentulous people, severe atrophy of the jawbone simulates the clinical appearance of a skeletal class III relationship (pseudoskeletal class III), which presents major problems for rehabilitation. This article describes the rehabilitation of a 67-year-old patient with a pseudoskeletal class III relationship. The mandible was restored with two implant-supported bar-retained overdentures using clips for retention. The extremely atrophic maxilla was restored with a combination of sinus augmentation, implant placement, and classic prosthodontic treatment using an electroformed mesostructured overdenture with swivel lock attachments on an implant-supported bar. By performing minimal augmentative and implant surgeries and using the possibilities and advantages of classic prosthetic dentistry, the clinical situation described here could be managed and the atrophic maxilla could be rehabilitated.

Interventions for replacing missing teeth: attachment systems for implant overdentures in edentulous jaws

BACKGROUND

Implant overdentures are one of the most common treatment options used to rehabilitate edentulous patients. Attachment systems are used to anchor the overdentures to implants. The plethora of attachment systems available dictates a need for clinicians to understand their prosthodontic and patient-related outcomes.

OBJECTIVES

To compare different attachment systems for maxillary and mandibular implant overdentures by assessing prosthodontic success, prosthodontic maintenance, patient preference, patient satisfaction/quality of life and costs.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 24 January 2018); Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 12) in the Cochrane Library (searched 24 January 2018); MEDLINE Ovid (1946 to 24 January 2018); and Embase Ovid (1980 to 24 January 2018). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials on 24 January 2018. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

All randomised controlled trials (RCTs), including cross-over trials on maxillary or mandibular implant overdentures with different attachment systems with at least 1 year follow-up.

DATA COLLECTION AND ANALYSIS

Four review authors extracted data independently and assessed risk of bias for each included trial. Several corresponding authors were subsequently contacted to obtain missing information. Fixed-effect meta-analysis was used to combine the outcomes with risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes, with 95% confidence intervals (95% CI). We used the GRADE approach to assess the quality of evidence and create 'Summary of findings' tables.

MAIN RESULTS

We identified six RCTs with a total of 294 mandibular overdentures (including one cross-over trial). No trials on maxillary overdentures were eligible. Due to the poor reporting of the outcomes across the included trials, only limited analyses between mandibular overdenture attachment systems were possible.Comparing ball and bar attachments, upon pooling the data regarding short-term prosthodontic success, we identified substantial heterogeneity (I² = 97%) with inconsistency in the direction of effect, which was unexplained by clinical or methodological differences between the studies, and accordingly we did not perform meta-analyses for this outcome. Short-term re-treatment (repair of attachment system) was higher with ball attachments (RR 3.11, 95% CI 1.68 to 5.75; 130 participants; 2 studies; very low-quality evidence), and there was no difference between both attachment systems in short-term re-treatment (replacement of attachment system) (RR 1.18, 95% CI 0.38 to 3.71; 130 participants; 2 studies; very low-quality evidence). It is uncertain whether there is a difference in short-term prosthodontic success when ball attachments are compared with bar attachments.Comparing ball and magnet attachments, there was no difference between them in medium-term prosthodontic success (RR 0.84, 95% CI 0.64 to 1.10; 69 participants; 1 study; very low-quality evidence), or in medium-term re-treatment (repair of attachment system) (RR 1.75, 95% CI 0.65 to 4.72; 69 participants; 1 study; very low-quality evidence). However, after 5 years, prosthodontic maintenance costs were higher when magnet attachments were used (MD -247.37 EUR, 95% CI -346.32 to -148.42; 69 participants; 1 study; very low-quality evidence). It is uncertain whether there is a difference in medium-term prosthodontic success when ball attachments are compared with magnet attachments.One trial provided data for ball versus telescopic attachments and reported no difference in prosthodontic maintenance between the two systems in short-term patrix replacement (RR 6.00, 95% CI 0.86 to 41.96; 22 participants; 1 study; very low-quality evidence), matrix activation (RR 11.00, 95% CI 0.68 to 177.72; 22 participants; 1 study; very low-quality evidence), matrix replacement (RR 1.75, 95% CI 0.71 to 4.31; 22 participants; 1 study; very low-quality evidence), or in relining of the implant overdenture (RR 2.33, 95% CI 0.81 to 6.76; 22 participants; 1 study; very low-quality evidence). It is uncertain whether there is a difference in short-term prosthodontic maintenance when ball attachments are compared with telescopic attachments.In the only cross-over trial included, patient preference between different attachment systems was assessed after only 3 months and not for the entire trial period of 10 years.

AUTHORS' CONCLUSIONS

For mandibular overdentures, there is insufficient evidence to determine the relative effectiveness of different attachment systems on prosthodontic success, prosthodontic maintenance, patient satisfaction, patient preference or costs. In the short term, there is some evidence that is insufficient to show a difference and where there was no evidence was reported. It was not possible to determine any preferred attachment system for mandibular overdentures.For maxillary overdentures, there is no evidence (with no trials identified) to determine the relative effectiveness of different attachment systems on prosthodontic success, prosthodontic maintenance, patient satisfaction, patient preference or costs.Further RCTs on edentulous cohorts must pay attention to trial design specifically using the same number of implants of the same implant system, but with different attachment systems clearly identified in control and test groups. Trials should also determine the longevity of different attachment systems and patient preferences. Trials on the current array of computer-aided designed/computer-assisted manufactured (CAD/CAM) bar attachment systems are encouraged.

The number of implants required to support a maxillary overdenture: a systematic review and meta-analysis

PURPOSE

The number of implants needed to support a maxillary overdenture is still a controversial issue. The aim of this systematic review was to investigate the number of implants required to support a maxillary overdenture in order to obtain optimal treatment outcomes in terms of implant survival, overdenture longevity and patient satisfaction.

STUDY SELECTION

Pubmed and EMBASE databes were systematically searched and complemented by hand searching from 2000 to 2017. The Prisma statement and a PICOS approach were adopted. All selected articles provided at least two-year follow-up and 10 totally edentulous patients. Survival rate of implants and overdentures were statistically analyzed according to number of implants and according to splitting technique, employing non-parametric Fisher Test for unpaired data. For the pooled analysis of implant failures, the odds ratio between group of 4 splinted implants and group of more than 4 splinted was calculated.

RESULTS

A total of 28 articles were included. Data analysis of the included studies showed that the survival rate of implants appeared higher in ≥ 4 implants group, whereas the high survival rate of overdentures and patient satisfaction were not significantly influenced by the number of implants.

CONCLUSIONS

The findings of our analysis indicate that overall the most frequent tendency is to place at least four implants, splinted or unsplinted, in order to ensure a higher survival rate of implants. However, the relationship between overdenture survival, the patient's quality of life, and the number of implants required to support a maxillary overdenture has yet to be clarified.

Mandibular Implant Overdentures: Treatment and Medico-Legal Considerations

The concept of a two-implant overdenture as the minimum standard of care or first choice treatment for the edentulous mandible was first proposed in 2002 and has since been backed by an overwhelming body of evidence supporting greater patient satisfaction and improved quality of life. This article examines the implant overdenture concept and its various options and discusses best practice from both the patient's and a medico-legal standpoint.

Biomechanical effects of implant number and diameter on stress distributions in maxillary implant-supported overdentures

STATEMENT OF PROBLEM

Implant-supported overdentures (ISOs) are considered a good alternative to conventional removable dentures. However, varying rates of failure have been reported in some clinical studies. Excessive stress on surrounding tissues is one of the possible causes of implant failure. As stress is transmitted to the bone through the implant, careful planning, correct number of implants, and implant positioning are keys to ensuring appropriate stress distribution. However, research of the optimal number of implants necessary to support a maxillary ISO is insufficient.

PURPOSE

The purpose of this in vitro finite element study was to determine the optimal implant location, number, and diameter to support a maxillary ISO.

MATERIAL AND METHODS

Three-dimensional models of an atrophic maxilla, dental implants, and ball attachments were modeled, and different loading conditions were applied to simulate realistic conditions. Six models with different numbers and diameters of implants, including mini-dental implants and differently located implants, were formed, and stress values were compared by implementing a finite element analysis.

RESULTS

The study showed that, as the implant number increased, decreased stress values were observed in peri-implant bone and implants in the maxillary ISO prosthesis. However, changes in implant diameter had no significant effect on stresses.

CONCLUSIONS

Increasing the implant diameter was not advantageous; the use of mini-dental implants may be a viable alternative method. However, using 4 implants for maxillary ISOs is indicated.

Single vs 2 Implants on Peri-implant Marginal Bone Level and Implant Failures in Mandibular Implant Overdentures: A Systematic Review With Meta-analysis

BACKGROUND

As a consensus, the 2-implant supported overdentures (ODs) are considered as the first choice of treatment for the edentulous mandible. In the same context, there is increased evidence supporting the use of single-implant OD. The aim of any design is to preserve the remaining structures and allow the longevity of the treatment.

OBJECTIVES

To evaluate the impact of single implant vs 2 implants on the peri-implant marginal bone loss (MBL) and number of implant failures in mandibular implant overdentures.

METHODS

A literature search of electronic databases (PubMed and Cochrane) was performed up to March 2016 and complemented by hand search. Randomized clinical trials (RCTs) that evaluated MBL and number of implant failures relative to single-implant mandibular overdenture (MOD) were selected. The review and meta-analysis were performed using meta-analytic statistical package and in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

FINDINGS

Five RCTs met the inclusion criteria for systematic review and qualitative synthesis. The observation period ranged from 12 months to 5 years in the selected RCTs. The comparison included in the meta-analysis is single- vs 2-implant MODs. Pooled data revealed that single-implant MODs significantly decreased the MBL (mean difference: 0.27, 95% confidence interval: 0.20-0.34, P < .0001, I² = 0%) and number of implant failures (risk ratio: 3.26, 95% confidence interval: 1.18-8.97), P = .02; I² = 0%).

CONCLUSIONS

Single-implant MOD was found to be better than 2-implant MOD in terms of MBL and number of implant failures. However, this result should be interpreted with caution due to limited number of analyzed studies with different loading protocols and short follow-up period.

Cost-effectiveness analysis of the single-implant mandibular overdenture versus conventional complete denture: study protocol for a randomized controlled trial

Background

Preliminary clinical studies on the single-implant mandibular overdenture (SIMO) have reported favorable results as an alternative to the conventional complete dentures for rehabilitation of the edentulous mandible. Clinical and patient-reported outcomes were assessed but no evidence is available with respect to the cost-effectiveness of this treatment, which is particularly important to test whether the incremental cost associated with the implant treatment is justified facing the benefits from the intervention. Thus, the aim of this study is to assess the cost-effectiveness of single-implant mandibular overdentures.

Methods/design

This randomized clinical trial will include edentulous individuals who meet eligibility criteria. Participants will be randomized into one of the treatment groups: a conventional complete denture group or a single-implant mandibular overdenture group. Direct costs related to therapies in both groups will be identified, measured and valuated for 1 year after treatment. Oral health-related quality of life and satisfaction with the dentures will be the primary outcome variables. Incremental cost-effectiveness ratios will be estimated and graphically presented on cost-effectiveness planes. A Markov decision tree will be constructed to set out the consequences of the competing alternatives. Sensitivity analysis on the most important assumptions will be performed in order to assess the robustness of the model.

Discussion

This is the first trial-based cost-effectiveness study on single-implant mandibular overdentures. Specific challenges in designing the protocol are considered. The expected results are of high clinical relevance and may contribute to the decision-making process when choosing between different alternatives for the rehabilitation of the edentulous mandible.

Trial registration

ClinicalTrials.gov Identifier: NCT02710357, registered on 11 March 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1646-0) contains supplementary material, which is available to authorized users.

A Comparative Analysis on Two Types of Oral Implants, Bone-Level and Tissue-Level, with Different Cantilever Lengths of Fixed Prosthesis

PURPOSE

Depending on esthetic, anatomical, and functional aspects, in implant-prosthetic restoration of a completely edentulous jaw, the selection of implant type is highly important; however, bone- and tissue-level implants and their stress distribution in bone have not yet been comparatively investigated. Hence, finite element analysis was used to study the influence of cantilever length in a fixed prosthesis on stress distribution in peri-implant bone around these two types of oral implants.

MATERIALS AND METHODS

A 3D edentulous mandible was modeled. In simulations, a framework with four posterior cantilever lengths and two types of implants, bone-level and tissue-level, was considered. A compressive load was applied to the distal regions of the cantilevers, and the von-Mises stress of peri-implant bone was investigated. The independent t-test and the Pearson correlation coefficient analyzed the results (α = 0.05).

RESULTS

Stresses in the cortical bone around the bone-level implants were greater than those in the tissue-level implants with the same cantilever length. In addition, by extending the cantilever length, the stress values in peri-implant bone increased. Therefore, when the cantilever was at its maximum length, the maximum stress was in cortical bone and around the bone-level distal implants.

CONCLUSION

The results of the present study indicate that treatment with tissue-level implants is potentially more advantageous than with bone-level implants for implant-supported fixed prostheses.

Biomaterial aspects: A key factor in the longevity of implant overdenture attachment systems

Background:

New attachment systems are released for mandibular two-implant overdentures often without evidence-based support. Biomaterial aspects are now the parameters considered when choosing the appropriate attachment. Studies regarding their properties remain scarce.

Purpose:

The purpose of this review was to help the clinician in selrcting the most adapted stud attachments according evidence-based dentistry.

Materials and Methods:

An electronic search was conducted using specific databases (PubMed, Medline, and Elsevier libraries). Peer-reviewed articles published in English up to July 2014 were identified. Emphasis was given on the biomaterial aspects and technical complications. No hand search was added.

Results:

The electronic search generated 115 full-text papers, of which 84 papers were included in the review. The majority were clinical and in vitro studies. Some review articles were also considered. Papers reported survival and failures of overdenture connection systems. Emphasis was laid on attachment deformation.

Conclusion:

Implant overdentures long-term follow-up studies may provide useful guidelines for the clinician in selecting the type of attachment system and overdenture design. Locator attachments are more and more used, with lesser complications reported.

Complications associated with implant-retained removable prostheses

Implant-supported removable prostheses improve patients' satisfaction with treatment and quality of life. Improvements in the implant's surface and in attachment elements have made this treatment method very successful. However, some biological and mechanical complications remain. Mechanical complications associated with implant-supported overdentures and implant-supported removable partial dentures are loss of retention of attachment systems, the need to replace retention elements and to reline or repair the resin portion of the denture, and implant fracture. Despite their success, implant-supported removable prostheses require periodic maintenance.

Implant-supported mandibular denture: planning to delivery--a case report

Restoring the edentulous mandible with a removable prosthesis can be a challenging prospect for both the dentist and patient during and after treatment. Poor retention and support are the major problems reported with a mandibular complete denture and these can be significantly improved with the use of implants and retentive attachments. Utilizing implants requires careful planning from both the surgical and restorative aspects to ensure that the intended treatment aim and outcome is achieved.

CLINICAL RELEVANCE

This case highlights the importance of both restorative and surgical considerations when planning the rehabilitation of the mandible with dental implants.

The 2-implant maxillary overdenture: a clinical report

Maxillary implant overdentures present a number of different challenges in comparison to the established and predictable benefits of mandibular implant overdentures. This report highlights the lack of evidence and conflicting findings in the maxillary implant overdenture literature and presents a clinical treatment of a 2-implant and subsequently 1-implant maxillary overdenture with reduced palatal coverage.

Stud attachments for the mandibular implant-retained overdentures: Prosthetic complications. A literature review

A plethora of attachment systems for mandibular two-implant overdentures is currently available often without evidence-based support. Technical aspects are now parameters considered when choosing the appropriate attachment. Despite the increasing use of the Locator attachments, studies regarding their properties remain scarce. Peer reviewed articles published in English up to 2011, were identified through a MEDLINE search (Pubmed and Elsevier) and a hand search of relevant textbooks and annual publications. Emphasis was made on the technical complications as well as the loss of retention related to the attachments in implant-retained overdentures, primarily the Locator attachment. The evaluation of the long-term outcome of implant overdentures and complications associated with different attachment systems may provide useful guidelines for the clinician in selecting the type of attachment system and overdenture design.

Performance of attachments used in implant-supported overdentures: review of trends in the literature

The purpose of this review is to examine the performance of attachments used in implant-supported overdenture (IOD) in both clinical and in vitro settings and report the compiled findings, comparisons, and trends in the research literature. Articles published in PubMed on IOD attachment systems and performance were reviewed. Non-original articles were excluded. For each article included, the type of study, number of implants, number of attachment systems, and study outcome were recorded. Of the 283 articles found, 158 met the inclusion criteria. Ninety-four articles were clinical studies and 64 articles were in vitro studies. Studies on retention were the most common for in vitro studies, and four or more attachment systems were compared in most articles with significant differences in outcome. A clinical outcome of one attachment system was most common for clinical studies, while most studies had neutral outcomes overall. Ball attachment was the most commonly tested IOD attachment system. The trend in the literature showed that there is a large discrepancy between the study designs and outcomes between the clinical and the in vitro studies for IOD. Further clinical studies that can validate in vitro research should be encouraged to address this discrepancy between the two areas.

Methodological quality and descriptive characteristics of prosthodontic-related systematic reviews

Ideally, healthcare systematic reviews (SRs) should be beneficial to practicing professionals in making evidence-based clinical decisions. However, the conclusions drawn from SRs are directly related to the quality of the SR and of the included studies. The aim was to investigate the methodological quality and key descriptive characteristics of SRs published in prosthodontics. Methodological quality was analysed using the Assessment of Multiple Reviews (AMSTAR) tool. Several electronic resources (MEDLINE, EMBASE, Web of Science and American Dental Association's Evidence-based Dentistry website) were searched. In total 106 SRs were located. Key descriptive characteristics and methodological quality features were gathered and assessed, and descriptive and inferential statistical testing performed. Most SRs in this sample originated from the European continent followed by North America. Two to five authors conducted most SRs; the majority was affiliated with academic institutions and had prior experience publishing SRs. The majority of SRs were published in specialty dentistry journals, with implant or implant-related topics, the primary topics of interest for most. According to AMSTAR, most quality aspects were adequately fulfilled by less than half of the reviews. Publication bias and grey literature searches were the most poorly adhered components. Overall, the methodological quality of the prosthodontic-related systematic was deemed limited. Future recommendations would include authors to have prior training in conducting SRs and for journals to include a universal checklist that should be adhered to address all key characteristics of an unbiased SR process.

Number of implants for mandibular implant overdentures: a systematic review

PURPOSE

The aim of this systematic review is to address treatment outcomes of Mandibular implant overdentures relative to implant survival rate, maintenance and complications, and patient satisfaction.

MATERIALS AND METHODS

A systematic literature search was conducted by a PubMed search strategy and hand-searching of relevant journals from included studies. Randomized Clinical Trials (RCT) and comparative clinical trial studies on mandibular implant overdentures until August, 2010 were selected. Eleven studies from 1098 studies were finally selected and data were analyzed relative to number of implants.

RESULTS

Six studies presented the data of the implant survival rate which ranged from 95% to 100% for 2 and 4 implant group and from 81.8% to 96.1% for 1 and 2 implant group. One study, which statistically compared implant survival rate showed no significant differences relative to the number of implants. The most common type of prosthetic maintenance and complications were replacement or reattaching of loose clips for 2 and 4 implant group, and denture repair due to the fracture around an implant for 1 and 2 implant groups. Most studies showed no significant differences in the rate of prosthetic maintenance and complication, and patient satisfaction regardless the number of implants.

CONCLUSION

The implant survival rate of mandibular overdentures is high regardless of the number of implants. Denture maintenance is likely not inflenced substantially by the number of implants and patient satisfaction is typically high again regardless os the number of implants.

Principles of implant-based reconstruction and rehabilitation of craniofacial defects

The final stages of reconstruction following craniofacial trauma or tumor resection often involve the fitting of prostheses. Development of osseointegrated implants for retention of prostheses has improved function and aesthetic outcome. Placement of osseointegrated implants requires coordinated care from multiple specialists and a lifetime commitment of the patient. The workup and surgical treatment algorithms for placement of intraoral compared with extraoral implants are discussed. The quality and quantity of bone available are the most important factors influencing design and placement. The long-term retention of implants is influenced by implant site, local tissue bed preparation, and hygiene. Osseointegrated implants are a part of the complete rehabilitation of patients with craniomaxillofacial defects. Although final fitting and maintenance of prostheses is completed by prosthodontists and patients, successful placement and preservation of implants is affected largely by the plan set forth by the reconstructive surgeon.