Four or six implants in the maxillary posterior region to support an overdenture: 5-year results from a randomized controlled trial

Effect of bar designs on peri implant tissues health in implant-supported removable prostheses: a systematic review

Different characteristics of bars (cross-sectional shape, diameter, distal extension etc.) lead to different biomechanical behavior (retention and stress) with implants and peri-implant tissues.Aim: To evaluate the impact of implant-supported removable prostheses bar designs in fully edentulous arch (in the maxilla and/or mandibula), with 4 implants or more, on the peri-implant soft and hard tissues.Two reviewers searched for observational studies, RCT and in vitro studies, published on five main databases and three from the grey literature, without restrictions on November 2023.Of the 3049 selected articles, four met the inclusion criteria. Four RCT evaluated peri-implant health tissues in full edentulous arches with 4 or 6 implants rehabilitated with implant bar overdentures. One prospective study with 5 years follow-up evaluated the success/survival rate of implants and implant bar overdentures. Overall, 261 subjects were enrolled in our systematic review with 1176 implants. Overdentures' survival rate was 100%. There was a trend that plaque indices and gingival indices were low in all of the studies, however no statistical analysis was done due to the lack of information.Due to the lack of information in the included studies, we cannot confirm if bar characteristics affect the peri-implant tissues health.

Maxillary implant overdentures retained with bars or solitary attachments: A 5-year randomised controlled trial

Purpose To compare the 5-year follow-up outcomes of maxillary overdentures retained by bars or solitary attachments.Methods Fifty consecutively selected fully edentulous patients experiencing problems with their conventional denture received four implants and were randomly allocated to receive a maxillary overdenture with either bar- or solitary attachment retention. Marginal bone level change (primary outcome), implant- and overdenture survival rate, clinical- and patient related outcome measures were recorded at baseline, and after 1 and 5 years. Biological and technical complications were recorded throughout the entire follow-up period.Results After 5 years, the mean marginal bone level change was higher in the solitary attachment group (-1.41±1.38mm, P=0.024) than in the bar group (-0.99±0.96mm). Also, fewer implants survived in the solitary attachment group (89.5%, P=0.027) than in the bar group (96.3%). The overdenture survival rate was 95.0% and 91.3% in the bar and solitary attachment group, respectively. Although the clinical and patient related outcomes were favourable and did not differ significantly between the groups, the peri-implantitis incidence was 25.8% in the solitary attachment group and 5.1% in the bar group. Any technical complications were minor.Conclusions In maxillary 4-implant overdenture therapy, the marginal bone level, implant survival rate and the number of complications are better with bar attachments than with solitary attachments. Both groups' clinical and patient related outcome measure scores were equal throughout the entire follow-up period.

Short Implants versus Standard Implants and Sinus Floor Elevation in Atrophic Posterior Maxilla: A Systematic Review and Meta-Analysis of Randomized Clinical Trials with ≥5 Years' Follow-Up

Background and objectives: The aim of this systematic review with meta-analysis was to assess the performance of short implants in comparison with standard implants and sinus floor elevation in atrophic posterior maxilla. Materials and methods: The protocol of the study was registered in the PROSPERO database (CRD42022375320). An electronic search on three databases (PubMed, Scopus, Web of Science) was performed to find randomized clinical trials (RCTs) with ≥5 years' follow-up, published until December 2022. Risk of bias (ROB) was calculated using Cochrane ROB. A meta-analysis was performed for primary (implant survival rate, ISR) and secondary outcomes (marginal bone loss, MBL; biological and prosthetic complications). Results: Of 1619 articles, 5 RCTs met the inclusion criteria. The ISR showed a risk ratio (RR) of 0.97 [0.94, 1.00] (CI 95%), p = 0.07. The MBL indicated a WMD of -0.29 [-0.49, -0.09] (CI 95%), p = 0.005. Biological complications showed a RR of 0.46 [0.23, 0.91] (CI 95%), p = 0.03. Prosthetic complications showed a RR of 1.51 [0.64, 3.55] (CI 95%), p = 0.34. Conclusions: The available evidence suggests that short implants might be used as an alternative to standard implants and sinus floor elevation. After 5 years, in terms of ISR, standard implants and sinus floor elevation showed a higher survival rate comparted to short implants, although statistical significance was not achieved. Future RCTs with long-term follow-up are needed to draw a clear conclusion on the advantages of one method over another.

Maxillary bar overdentures on four or six posterior implants: 10-year results from a randomized clinical trial

OBJECTIVE

To compare clinical and patient-reported outcomes when providing maxillary overdentures on four and six splinted implants placed in the posterior region during a 10-year follow-up period.

MATERIALS AND METHODS

Sixty-six edentulous participants with functional maxillary denture complaints and insufficient bone volume to allow implant placement were scheduled for a bone augmentation procedure. After healing, participants were randomized to receive either four or six implants in the posterior maxilla. After 3 months of osseointegration, a bar overdenture was constructed. Implant survival, overdenture survival, clinical scores, peri-implant bone height changes, and patient satisfaction were assessed.

RESULTS

Forty-six participants completed the 10-year follow-up. Implant survival was 100% in the 4-implant group and 96.7% in the 6-implant group. Seven new overdentures were made in the 4-implant group and 12 new overdentures were made in the 6-implant group due to excessive wear of the denture base and teeth. Clinical parameters did not differ significantly between groups. Mean marginal bone loss compared to baseline was 0.41 ± 0.37 mm in the 4-implant group and 0.70 ± 1.07 mm in the 6-implant group. Overall, patient satisfaction improved significantly, but did not differ between groups.

CONCLUSION

From this 10-year follow-up trial, it was concluded that bar maxillary overdentures on four or six implants in the posterior region of an augmented maxilla resulted in a comparable treatment outcome with high implant survival, limited loss of peri-implant marginal bone, and high patients' satisfaction. (Clinical trial registration number: NTR9729).

Incidence of peri-implant mucositis and peri-implantitis in patients with a maxillary overdenture: A sub-analysis of two prospective studies with a 10-year follow-up period

Background

Though studies on maxillary overdentures show satisfying results on implant survival, patient‐related outcomes and prosthetic complications, the epidemiology of peri‐implant diseases in this specific group of patients has hardly been reported. While the general patient‐level prevalence of peri‐implant mucositis and peri‐implantitis are estimated at ~45% and ~20%, respectively, the risk of developing these diseases within a specific period is less clear. To fully appreciate the epidemiology of peri‐implant diseases, more long‐term data on incidence of peri‐implant diseases are needed.

Purpose

The purpose of this sub‐analysis of two prospective studies was to assess the incidence of peri‐implant mucositis and peri‐implantitis in fully edentulous patients with implant‐retained maxillary overdentures during a 10‐year follow‐up period.

Materials and Methods

One hundred and sixteen patients treated with implant‐supported maxillary overdentures were available from two clinical trials. Data on biological complications, clinical and radiographical parameters were collected for 106 patients at 5‐year, for 82 patients at 10‐year follow‐up. The incidence was calculated following the consensus of the 2017 World Workshop on the Classification of Periodontal and Peri‐Implant Diseases and Conditions. Extent and severity then were calculated to enable an appropriate epidemiological description of peri‐implantitis.

Results

The patient‐level incidence of peri‐implant mucositis was 37.7% after 5 years and 64.6% after 10 years whereas the patient‐level incidence of peri‐implantitis was 10.4% after 5 years and 19.5% after 10 years. After 10 years, the extent of peri‐implant mucositis and peri‐implantitis is 52.8% and 43.8%, respectively. In terms of severity, 26.5% of all affected implants suffered from >3 mm bone loss and 17.6% of all affected implants was lost.

Conclusion

Three of five fully edentulous patients with implant‐supported maxillary overdentures experience peri‐implant mucositis after 10 years. Peri‐implantitis occurs in one of five patients after 10 years. In spite of these incidence rates, implant survival remains high.

Patient's perception of recovery after sinus membrane elevation and blood coagulum compared with 1:1 mixture of autogenous bone graft and deproteinized porcine bone mineral. Secondary outcomes from a single-blinded randomized controlled trial

OBJECTIVE

The objective was to assess patient's perception of recovery after maxillary sinus membrane elevation (MSME) and blood coagulum (test) compared with maxillary sinus floor augmentation (MSFA) and 1:1 mixture of autogenous bone graft from the buccal antrostomy and deproteinized porcine bone mineral (DPBM) (control).

MATERIALS AND METHODS

Forty healthy patients were randomly allocated to test or control. Oral health-related quality of life (OHRQoL) was evaluated by Oral Health Impact Profile-14 (OHIP-14) at enrollment and 1 week postsurgical. Recovery was estimated by questionnaires and visual analog scale assessing pain, social and working isolation, physical appearance, eating and speaking ability, diet variations, sleep impairment, and discomfort after 1 week and 1 month. Mean differences were expressed with 95% confidence interval (CI). Association between OHRQoL and recovery was estimated. p-value below .05 was considered statistically significant.

RESULTS

Maxillary sinus membrane elevation revealed 2.1 less days of pain (p = .03, 95% CI: 0.2-4.1) and 1.2 days of sick leave (p = .01, 95% CI: 0.3-2.1) compared with MSFA. No significant difference was observed in eating and speaking ability, physical appearance, work performance, and sleep impairment. No significant association between impaired OHRQoL and recovery was observed. Females reported 4.77 higher OHIP-14 score compared with males (p = .01, 95% CI: 1.60-7.94), while association between age and OHIP-14 was -0.10 (p = .28, 95% CI: -0.28 to 0.08).

CONCLUSION

Maxillary sinus membrane elevation revealed significantly less days of pain and sick leave compared with MSFA. Harvesting of autogenous bone graft seems, therefore, to have a significant impact on perception of recovery.

Four-implant-supported overdenture treatment in the maxilla. Part I: A randomized controlled split mouth trial assessing the effect of microthreads and abutment connection type on 4 years peri-implant health

BACKGROUND

According to literature, peri-implant bone loss is minimized on implants with microthreaded neck design and internal type of abutment connection. However, most clinical studies may be biased due to confounding factors.

PURPOSE

This nonblinded RCT assessed the effect of implant neck (microthreaded vs non-microthreaded) as well as the type of abutment connection (internal conical vs external flat-to-flat) on peri-implant bone stability and peri-implant health after at least 36 months.

MATERIALS AND METHODS

Twenty-five patients were treated with a maxillary implant-supported bar-retained overdenture on four different implant types: internal connection with microthreads (I-MT), internal connection without microthreads (I-NMT), external connection with microthreads (E-MT), and external connection without microthreads (E-NMT). To control confounding factors, all other design features were similar. A linear mixed-model analysis or mixed-model logistic regression analysis was used to determine the effect of implant type on bone level, probing pocket depth, bleeding on probing, and plaque.

RESULTS

Four out of 98 implants (4.1%) placed in 25 patients failed during provisionalization and were replaced. Mean overall bone loss after 6 months was 0.39 mm (SD 0.62, range 0.00-3.48) with limited additional bone loss of 0.04 mm (SD 0.54, range -1.80-1.63) after at least 3 years. Microthreads or connection type had no effect on the bone level, probing pocket depth, bleeding on probing, nor plaque.

CONCLUSIONS

With 96% of implant survival, the maxillary overdenture supported with a bar on four implants yield a predictable outcome and the implant-abutment connection type (internal vs external) and implant neck design (microthreaded vs non-microthreaded) have no influence on peri-implant bone remodeling after initial bone remodeling nor up to 4 years of function. Peri-implant bone levels are within international success standards and peri-implant health is indicative of absence of peri-implantitis.

Patient satisfaction and survival of maxillary overdentures supported by four or six splinted implants: a systematic review with meta-analysis

Background

Implant-supported overdentures offer enhanced mechanical properties, which lead to better patient satisfaction and survival rates than conventional dentures. However, it is unclear whether these satisfaction levels and survival rates depend on the number of implants supporting the overdenture. Therefore, this systematic review aimed to compare maxillary overdentures supported by four or six splinted implants in terms of patient satisfaction, implant survival, overdenture survival, and prosthodontic complications.

Methods

Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (PubMed), and EMBASE databases were systematically searched and complemented by hand searching from 2000 to 2019, employing a combination of specific keywords. Studies comparing the use of four versus six implants for supporting overdentures with at least one-year of follow-up after prosthesis installation and including ten fully edentulous patients were included. The risk of bias (RoB) was analyzed with Cochrane’s RoB 2 and Newcastle–Ottawa tools. Implants and prosthesis survival rates were analyzed by random-effects meta-analysis and expressed as risk ratios or risk differences, respectively, and by the non-parametric unpaired Fisher’s test.

Results

A total of 15 from 1865 articles were included, and reported follow-up times after implant placement ranged from 1 to 10 years. Irrespective of the number of implants used, high scores were reported by all studies investigating patient satisfaction. Meta-analysis and non-parametric Fisher’s test showed no statistical differences regarding the survival rate of implants (P = 0.34, P = 0.3) or overdentures (P = 0.74, P = 0.9) when using 4 versus 6 splinted implants to support overdentures, and no significant differences regarding prosthodontic complications were found between groups. Randomized studies presented high RoB and non-randomized studies presented acceptable quality.

Conclusions

Within the limits of this systematic review, we can conclude that the bar-supported overdenture on four implants is not inferior to the overdenture supported by six implants for rehabilitating the edentulous maxilla, in terms of patient satisfaction, survival rates of implants and overdentures, and prosthodontic complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01572-6.

A digital approach to robust and esthetic implant overdenture construction

OBJECTIVE

Overdenture therapy is an important option for implant rehabilitation. However, numerous reports suggest that mechanical/technical complications and failures can limit therapeutic success. The goal of this report is to illustrate a digital approach to design and construction of a robust overdenture with high-esthetic value.

MATERIALS AND METHODS

Beginning with new denture design to establish esthetic parameters, 3D modeling of a metal framework and the denture teeth are completed in a connected manner. This enables connection of rapidly printed, prototype dentition that is attached directly to the framework without intervening wax or acrylic components. Following evaluation of the dentition and required adjustments, the final dentition is milled from resin and processed to the selective laser sintered framework.

RESULTS

The advantages of the digital workflow include the control of dimensions and strength of the framework, the esthetic relationship of the framework to the dentition and the facilitation of esthetic try-in of the dentition.

CONCLUSION

Enhancing a robust overdenture can be readily achieved using a digital workflow.

CLINICAL SIGNIFICANCE

The use of digital technology enables the clinical team to plan and produce prostheses with dimensions and contours that support long-term function and esthetics. The clinical chair time can be potentially reduced by use of digital design that facilitates try-in and reduces major errors by improved communication between the patient, dentist, and technician.

"Longitudinal Oral Health-Related Quality of Life in maxillary mini dental implant overdentures after 3 years in function"

OBJECTIVES

Longitudinal evaluation of Oral Health-Related Quality of Life (OHRQoL) during treatment of flaplessly placed, one-piece mini-dental-implants (MDIs) for maxillary overdentures is rarely investigated, nor is the impact of MDI failures.

MATERIAL AND METHODS

This multicenter prospective cohort study evaluated the 3-year outcome of 5-6 MDIs in the edentulous maxilla in patients above 50 years with dentate mandible. Provisional dentures were provided before final prosthetic connection was established at 6 months. Postoperative discomfort was assessed using a visual analogue score (VAS). OHRQoL was investigated using the Oral Health Impact Profile (OHIP)-14 at baseline (preoperatively), postoperatively, post-prosthetic connection and after 3 years in function.

RESULTS

164 (78.4%) of the 204 placed MDIs were still in situ after 3 years, in 29/31 patients. Two patients lost 5/6 MDIs resulting in two prosthetic failures (6.45%). With regard to pain, a score of 4.1/10 (SD 2.8) was recorded on day 1, and 1.1/10 (SD 1.7) on day 7. A decrease in total OHIP-14 scores was observed postoperatively (15.6; SD 12.8) as compared to baseline (21.3; SD 13.1), with improvement of OHRQoL. Furthermore, this was statistically significant at connection of the final prosthesis (7.3; SD 6.7) (p = .006). The OHIP-14 improved less (p = .011) when experiencing one or more implant losses (9.5; SD: 9.85), in comparison with no implant loss (20.7; SD: 13.97). A failure of one MDI did not affect OHIP-14 score (p = .658); however, multiple failures did (p = .007).

CONCLUSION

Maxillary MDI overdenture treatment yields significant OHRQoL improvement when at least 5 MDIs survive, preserving functional comfort.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

This comprehensive review of the 2019 restorative dental literature is offered to inform busy dentists regarding remarkable publications and noteworthy progress made in the profession. Developed by the Scientific Investigation Committee of the American Academy of Restorative Dentistry, each author brings discipline-specific expertise to 1 of 8 sections of the report: (1) prosthodontics; (2) periodontics, alveolar bone, and peri-implant tissues; (3) implant dentistry; (4) dental materials and therapeutics; (5) occlusion and temporomandibular disorders; (6) sleep-related breathing disorders; (7) oral medicine and oral and maxillofacial surgery; and (8) dental caries and cariology. The report targets important information likely to influence day-to-day dental treatment decisions. Each review is not intended to stand alone but to update interested readers so that they may visit source material when greater detail is desired. As the profession moves toward evidence-based clinical decision-making, an incredible volume of potentially valuable dental literature continues to increase. It is the intention of this review and its authors to provide assistance in negotiating the extensive dental literature published in 2019. It is our hope that readers find this work useful in the clinical management of dental patients.

Three-Dimensional Radiographic Outcome of Free-Handed Flaplessly Placed Mini Dental Implants in Edentulous Maxillae after 2-Years Function

Background: Free-handed, flaplessly placed mini dental implants (MDIs) are a valuable, more affordable and minimally invasive treatment to support overdentures in fully edentulous jaws, especially for medically compromised patients. However, critical 3D radiographic evaluation is lacking. This multicenter prospective case series assessed clinical outcome and carried out 3D- cone-beam computerized tomography (CBCT) analysis of free-handed flaplessly placed one-piece maxillary MDIs by an experienced maxillofacial surgeon. Methods: Thirty-one patients suffering from an ill-fitting maxillary denture relating to compromised bone volume (as confirmed on CBCT), with a dentate mandible, were selected. They received 5–6 MDIs free-hand flaplessly placed and mentally guided with preoperative CBCT. Final connection and attachment activation took place six months later. After two years each implant was individually assessed with CBCT for perforations on eight sites. Implant survival, prosthetic failure, clinical stability and sinus/nasal complaints were registered after three years. Results: 32/185 (17.3%) MDIs failed during the provisional loading with non-activated attachments; 17 replacements in 10 patients were performed. Of the 170 actively loaded 170 MDIs, 82.3% survived and 27/31 prostheses (87%) were fully functional. In total 98/170 MDIs showed no perforation. Based on 1360 CBCT observations, 231 perforations (16.9%) were registered. Of most perforations 37 (25%) were observed at the apical tip and 37 were positioned (21%) into the sinus/nasal cavity, although without clinical complaints. Conclusions: Given the compromised population, the minimally invasive procedure and the low treatment cost involved, a failure rate of 17% is substantial, however clinically acceptable given the critical bone condition. However, even in experienced surgical hands, freehanded and flapless placement yield a high risk for implant perforation, although this did not necessarily lead to complications.

How many implants are necessary to stabilise an implant-supported maxillary overdenture?

Data sources Pubmed and EMBASE databases were searched from 2000 to 2017 and complemented by manual searching of the references of reviews and the full-text articles assessed for inclusion.Study selection The inclusion criteria were: (i) Randomised clinical trials (RCT), prospective or retrospective studies, and case series or case reports including at least ten totally edentulous patients rehabilitated with maxillary implant-supported overdenture; (ii) analysed one of the following outcomes: survival rate of the implants, survival rate of the overdenture and patient-reported results; (iii) had at least two years of follow-up; (iv) and were written in English language.Data extraction and synthesis The data extraction was performed by two independent reviewers. The comparison of the analysed outcomes was performed by nonparametric Fisher Test for unpaired data according to the number of implants and to the splinting technique. A meta-analysis was performed for the odds ratio (OR) for implant failure between four splinted implants and more than four splinted implants.Results Twenty-eight studies were included in the systematic review. The survival rate of implants appeared to be higher when at least four implants were placed to support the overdenture, compared to less than four implants. The survival rate of overdentures and the patient satisfaction were not influenced by the number of implants.The metanalysis could only be performed to compare the implant survival rate of a four splinted implants group and more than 4 splinted implants group, without significant differences between both groups (OR = 0.39; 95 % CI: 0.14, 1.14; p = 0.09).Conclusions Although the placement of at least four implants to support a maxillary overdenture seems to report higher implant survival rates, further studies are needed to confirm this conclusion. No differences were found for overdenture survival rates or patient satisfaction according to the number of implants.

Clinical and patient-reported outcome of implant restorations with internal conical connection in daily dental practices: prospective observational multicenter trial with up to 7-year follow-up

Background

The interpretation of the results of randomized clinical trials is often questioned in relation with daily circumstances in practices. This prospective observational multicenter study was instigated to reflect the need for information in real-life situations with dental implants with internal conical implant-abutment connection (Conelog implant system). The implants were followed up at least 5-year post-loading; survival analysis (Kaplan-Meier), changes of soft tissue, and bone level over time, as well as patient satisfaction were evaluated.

Results

In total, 130 dental implants were placed in 94 patients (64 female, 30 male). Mean age of patients was 50.4 ± 13.7. At 5-year post-loading, 104 implants in 76 patients were available for evaluation. The cumulative implant survival rate was 96.6%. After an initial bone remodeling process post-surgery (bone loss of − 0.52 ± 0.55 mm), the bone level change remained clinically stable from loading to 5-year post-loading (− 0.09 ± 0.43 mm). Patient satisfaction surveyed by questionnaire (comfort, ability to chew and taste, esthetics, general satisfaction) steadily increased towards the end. At the last study follow-up, all the patients rated their general satisfaction as either very satisfied (87.5%) or satisfied (12.5%).

Conclusion

The study implants have shown to be highly effective with reliable peri-implant tissue stability over the 5 to 7 years of observation for both single tooth restorations and fixed partial dentures while used in standard conditions in daily dental practice. The results obtained are comparable with those obtained in controlled clinical trials.

Retreatment of multiple failing maxillary implants after full arch rehabilitation: a retrospective, observational cohort study

The aim of this study was to assess implant retreatment in a group of patients whose maxillary implants were all failing after full arch rehabilitation. Treatment involved implant removal, augmentation, and placement of an overdenture supported by four to six implants. All consecutive patients referred between 2008 and 2018, following multiple late implant failures in the rehabilitated maxilla, were included in the study. Seventy implants in 15 patients were evaluated at 3.3 ± 2.5 years (range 1.1-8.6 years) after loading. Implant survival, complications, clinical parameters, marginal bone loss, and patient-related outcome measures were recorded at the time of evaluation. Overall implant survival was 95.7%. Three implant failures occurred within the first year of function. Marginal bone loss was 0.32 ± 0.46 mm; pocket probing depth was 4.55 ± 1.59 mm. Plaque, calculus, inflammation, and bleeding were hardly seen (median index score 0). Patients scored their satisfaction with their overdentures as high (mean overall score 8.7 ± 1.2, maximum 10). Chewing soft and tough food was scored as 'good' and hard food as 'moderate'. The mean Oral Health Impact Profile score was 29.5 ± 33.3. It can be concluded that the replacement of multiple failing implants in an edentulous maxilla after bone augmentation is a safe and predictable treatment procedure when applied as an implant-supported overdenture.

Maxillary Implant-Supported Overdentures: Mechanical Behavior Comparing Individual Axial and Bar Retention Systems. A Cohort Study of Edentulous Patients

Background and objectives: To compare the medium- to long-term mechanical behavior of overdentures with two different retention systems: overdentures with Locator® axial retention, and vertical insertion overdentures with bar retention, used to rehabilitate edentulous maxillar. Material and Methods: This prospective study assessed patients presenting complete maxillary edentulism, rehabilitated by means of implant-supported overdentures (n = 20), 10 with Locator® axial retention (ODA group) and 10 with overdentures on bars (ODB group). Patients also completed a questionnaire to determine their satisfaction with treatment. Results: The mean follow-up time in both groups was 11.4 years, with follow-up times in both groups ranging from 5 to 14 years. The ODA group suffered mechanical complications such as retention loss, need for nylon retention insert changes, resin fracture, and need for relining. In the ODB group, prosthetic dental wear, screw loosening, and complete prosthetic failure were more common. A total of 19 implants failed (23.8%); of these, 11 were in the ODA group (failure rate = 27.5%) and eight in the ODB group (failure rate = 20%). The patient satisfaction questionnaire obtained a mean score of 7.9 out of 10 in the ODA group, and 9.75 in the ODB group. Conclusions: in rehabilitations of edentulous maxillar by means of implant-supported overdentures, both the systems assessed were shown to be effective in the medium to long term. Patients expressed a high level of satisfaction with the treatments received.

Long-term effectiveness of maxillary sinus floor augmentation: A systematic review and meta-analysis

AIM

To assess the long-term effectiveness (≥5 years) of maxillary sinus floor augmentation (MSFA) procedures applying the lateral window technique and to determine possible differences in outcome between simultaneous and delayed implant placement, partially and fully edentulous patients and grafting procedures.

MATERIALS AND METHODS

MEDLINE (1950-May 2018), EMBASE (1966-May 2018) and Cochrane Central Register of Controlled Trials (1800-May 2018) were searched. Inclusion criteria were prospective studies with follow-up ≥5 years and a residual bone height ≤6 mm. Outcome measures included implant loss, peri-implant bone level change, suprastructure survival, patient-reported outcome measures and overall complications. Data were pooled and analysed using a random effects model.

RESULTS

Out of 2,873 selected articles, 11 studies fulfilled all inclusion criteria. Meta-analysis revealed a weighted annual implant loss of 0.43% (95% CI: 0.37%-0.49%). Meta-regression analysis did not reveal significant differences in implant loss neither between edentulous and dentate patients nor implants placed simultaneously with or delayed after MSFA, nor implants placed in MSFA using solely autologous bone or bone substitutes. The results of the other outcome measures were favourable, and overall complications were low.

CONCLUSION

MSFA is a reliable procedure in the partially and fully edentulous maxilla for support of dental implants.

Bar versus ball attachments for maxillary four-implant retained overdentures: A randomized controlled trial

OBJECTIVES

To compare the clinical treatment outcomes of maxillary four-implant retained overdentures with either splinted (bar) attachments or non-splinted (ball) attachments.

MATERIAL AND METHODS

Forty participants who were dissatisfied with their existing conventional maxillary complete dentures were included in this randomized controlled trial. Six months after implant placement, a definitive prosthesis was inserted. Implant success, condition of peri-implant tissue, prosthodontic maintenance and complications, and patient satisfaction were assessed. Outcomes were recorded at baseline, prosthesis delivery, and at 3 and 12 months following prosthesis delivery, and a statistical analysis was performed.

RESULTS

Thirty-two of the forty patients completed the 1-year follow-up and had their treatment outcomes evaluated. The mean marginal bone loss after 1 year of loading was 0.34 ± 0.88 mm, and there were no significant differences between the two groups. Plaque index, gingival index and bleeding on probing were significantly higher in the bar group (p<.001), and the implant success rate of the bar group was significantly lower than that of the ball group (p=.028). The most frequent prosthodontic maintenance and complication issue was the need to change the bar clip or O-ring as a result of retention loss. Patient satisfaction did not differ between the two groups except for aesthetics at 3 months.

CONCLUSIONS

Within the limitations of this study, the maxillary 4-implant retained overdenture exhibited predictable results regardless of the attachment systems (ball or bar) in the 1-year follow-up period. The bar group was more vulnerable than the ball group with respect to maintaining peri-implant tissue health.