Clinical evaluation of mandibular implant overdentures via Locator implant attachment and Locator bar attachment

Clinical performance of implant supported mandibular overdentures with cantilever bar and stud attachments: A retrospective study

BACKGROUND

Treatment of edentulous patients with implant-supported over-dentures improves denture's retention and stability. Published data concerning implant-supported overdenture with cantilever bars that claimed that can affect the survival and bone loss of implants are scarce.

PURPOSE

The purpose of this study was to evaluate 5-year clinical performance of mandibular implant-supported over-dentures with different attachment systems.

MATERIALS AND METHODS

In this retrospective study, 103 patients who had received mandibular over-dentures supported by two implants were evaluated in a 5-year follow up. Studied groups were patients with Spherblock ball attachment (58 patients), Dolder bar with cantilever (36 patients), and Locator attachment (9 patients). Marginal bone-loss around implants, prosthetic complications, soft tissue status of the implants (gingival index, plaque index, pocket depth, and bleeding on probing) were used to compare studied groups. Visual Analogue Scale (VAS) criteria was used to assay patient's satisfaction. One-way ANOVA, Scheffe, Kruskal-Wallis, Mann-Whitney, and Fisher's exact tests, were used for the data analysis (α = 0.05).

RESULTS

One hundred and three patients (46 male, 57 female, mean age 64.7 ± 8.6) with 206 implants (Strauman) were studied. The implant survival rate was 100% with mean bone loss of 0.22 mm around implants in 5 years. Prosthetic complications including attachment wear and denture fracture occurred more often with ball attachments. The number of attachment replacement, and post insertion appointments were significantly less in patients with bar attachments (p < 0.05). Pocket depth and gingival index were less in the ball attachment (p < 0.05).

CONCLUSION

Mandibular overdenture supported by two implants can be considered a successful treatment in edentulous patients. The frequency of prosthetic complication is higher in unsplinted than splinted superstructures.

Current complications and issues of implant superstructure

The purpose of this review is to search for complications of dental implant superstructures and consider the issues involved. This narrative review was performed by searching through PubMed databases and review articles that were published after 1990. Misfitting of the superstructure can result in loosening of screws, reduced preload, and in some cases, significant stress around the implant. External connection modalities and single implant prostheses have been reported to have more loose or broken abutment screws. In addition, when zirconia abutment was used for platform shifting, the rate of fracture of the abutment was considered to be high. Additionally, it was reported that men were significantly at an increased risk of abutment fracture. As for the retention mechanism of implant overdenture, stud attachment (Locator type) should receive more attention to wear and damage of retention parts than other attachments. The causes of the complications of implant superstructures have not been clarified in some cases, and further verification is required. Verification of complications is considered important to obtain a long-term prognosis for superstructures of implants. It will be necessary to further verify complications of implants in the future.

Maintenance requirements and marginal bone loss associated with implant-retained overdentures: a retrospective cohort study

OBJECTIVES

To evaluate the maintenance requirements and the presence of prosthetic complications associated with marginal bone loss in the implant-retained bar and locator prostheses.

MATERIALS AND METHODS

The study was executed between the years 2013 and 2018 on 114 patients who had undergone 283 dental implants. Patients were examined at follow-up recall sessions at 12 and 24 months after the placement of the dentures. The clinical examination also included intraoral and extraoral examinations of the patients; compatibility of the prostheses placed to about occlusion; an adaptation of the prosthesis to the tissues, health, and continuity of the soft tissues; complaints of the patients; implant success rates; and marginal bone loss, and prosthetic complications were evaluated at follow-up sessions, and statistical analysis was performed.

RESULTS

Locator attachment was placed in 94 patients with separated mandibles and maxillae, and a removable prosthesis with a bar attachment was placed in 20 patients. When evaluating the level of marginal bone loss regardless of the presence of complications, the area where the implant was set, the number of days after loading, and the type of retainer, it was found to be significant at the end of the 12th the 24th months. The results showed a significant relationship between the prosthesis type and the presence of complications at month 24 (p < 0.05). There was no significant relationship between the position of the denture and the presence of complications at month 12 (p > 0.05). There was no significant relationship between the location of the denture and the presence of complications at month 24 (p > 0.05).

CONCLUSION

Complications do not affect marginal bone loss, but the resulting marginal bone loss is the result of the patient not paying enough attention to oral hygiene. Routine inspections of the prosthesis after the completion of treatment seem to be important. If the requirements resulting from these checks are met, complications that may occur in the future will be prevented.

CLINICAL RELEVANCE

The maintenance requirements and the presence of prosthetic complications associated with marginal bone loss in the implant-retained bar and locator prostheses were evaluated. Complications occurred more frequently with the bar-supported removable implant prostheses.

Comparison of retentive force and wear pattern of Locator® and ADD-TOC attachments combined with CAD-CAM milled bar

PURPOSE

The purpose of this study was to investigate changes in retention and wear pattern of Locator® and ADD-TOC attachments on a digital milled bar by performing chewing simulation and repeated insertion/removal of prostheses in fully edentulous models.

MATERIALS AND METHODS

Locator (Locator®; Zest Anchors Inc., Escondido, CA, USA) was selected as the control group and ADD-TOC (ADD-TOC; PNUAdd Co., Ltd., Busan, Republic of Korea) as the experimental group. A CAD-CAM milled bar was mounted on a master model and 3 threaded holes for connecting a bar attachment was formed using a tap. Locator and ADD-TOC attachments were then attached to the milled bar. Simulated mastication and repeated insertion/removal were performed over 400,000 cyclic loadings and 1,080 insertions/removals, respectively. Wear patterns on deformed attachment were investigated by field emission scanning electron microscopy.

RESULTS

For the ADD-TOC attachments, chewing simulation and repeated insertion/removal resulted in a mean initial retentive force of 24.43 ± 4.89 N, which were significantly lower than that of the Locator attachment, 34.33 ± 8.25 N (P < .05). Amounts of retention loss relative to baseline for the Locator and ADD-TOC attachments were 21.74 ± 7.07 and 8.98 ± 5.76 N (P < .05).

CONCLUSION

CAD-CAM milled bar with the ADD-TOC attachment had a lower initial retentive force than the Locator attachment. However, the ADD-TOC attachment might be suitable for long-term use as it showed less deformation and had a higher retentive force after simulated mastication and insertion/removal repetitions.

Effects of attachment type and number of dental implants supporting mandibular overdenture on peri-implant health: A systematic review and network meta-analysis

PURPOSE

To evaluate the effect of overdenture (OD) attachment type and the number of implants supporting mandibular ODs on peri-implant health.

STUDY SELECTION

From inception to October 2020, electronic databases (Medline/PubMed, Embase, Cochrane Library, and Scopus) were systematically searched. The outcomes of interest were marginal bone loss (MBL), pocket probing depth (PPD), plaque index, bleeding index, and implant survival rate. Bayesian network meta-analysis was performed using the GeMTC package supported by R. The weighted mean difference and 95% credible interval were estimated.

RESULTS

Twenty-eight studies with a total of 1166 participants who received 2666 dental implants were included. Except for 4 bar and 4 telescopic, which showed a statistically lower MBL than the 2 locator, all other interventions showed insignificant differences in MBL (P > 0.05). The difference in periodontal probing depth was not statistically significant when comparing the different groups. The pooled implant survival rates of the different interventions ranged from 88.9% to 100%. The rank probability test showed that 4 bar and 4 telescopic had the lowest MBL, 2 magnet and 2 bar had the highest PI, whereas 4 locator showed the least PPD.

CONCLUSIONS

Except for 4 implants+bar, or telescopic, and 4 locator that, respectively, showed less MBL and PPD compared to some interventions, it seemed that different attachment types and number of implants supporting mandibular ODs have no clear superiority over the other in terms of peri-implant health outcomes.

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.

Patient satisfaction and masticatory performance of zirconia bar compared to cobalt chromium bar retaining mandibular implant overdenture: A crossover study

OBJECTIVES

The aim of this crossover clinical study was the evaluation and comparison of patient satisfaction and masticatory performance for patients rehabilitated with mandibular two implant overdentures retained with two different bar attachments: zirconia bar and cobalt chromium bar.

MATERIAL AND METHODS

Twenty completely edentulous patients were divided into two equal groups: Group I (ZrO2), each patient received mandibular implant overdenture retained with CAD/CAM zirconia bar on two implants in the canine region, and Group II (Co-Cr), each patient received mandibular overdenture retained with conventional casted cobalt chromium metal bar. Patient satisfaction was measured with a survey questionnaire (PSQ-18), and masticatory performance was also evaluated with the two-colour mixing ability test after 3 months of overdenture insertion; then, each patient received a bar attachment from the other type and evaluations were repeated.

RESULTS

Significant differences were observed regarding psychological acceptance (appearance), time, hygiene, undergo procedures, recommend procedures and the overall experience. In contrast, insignificant difference was observed regarding speech, chewing capacity, restorative procedures, complications and information prior to treatment. No significant difference was reported when comparing chewing performance between the two types of bar attachment.

CONCLUSION

Within this clinical study limitations, patient satisfaction with zirconia bar was higher than Co-Cr bar in terms of appearance, time, hygiene, undergo procedures, recommend procedures and the overall experience. Zirconia can become a suitable alternative to cobalt chromium alloys as a bar attachment. Combining the advantages of implant supported overdenture, CAD/CAM zirconia bar as an attachment, a satisfactory non-metal prosthesis could be provided.

Cost and complications associated with implant-supported overdentures with a resilient-attachment system: A retrospective study

STATEMENT OF PROBLEM

Implant-supported overdentures with a splinted or nonsplinted attachment system have been a successful treatment option for edentulous mandibles with excessive hard tissue resorption. Currently, the 2 most common treatment approaches for an implant overdenture uses either a bar attachment system (splinted) or resilient (LOCATOR)-attachment system (nonsplinted). The LOCATOR-attachment system is often chosen for the lower initial cost. However, whether the ongoing maintenance costs of the LOCATOR-attachment system increase the overall cost of this system is unclear.

PURPOSE

The purpose of this retrospective study was to investigate the frequency of maintenance procedures, complications, and costs associated with the LOCATOR-supported overdenture treatment.

MATERIAL AND METHODS

The retrospective data of 75 patients who had received implant-supported overdentures with LOCATOR-attachments at the University of Colorado School of Dental Medicine in the previous 10 years were collected and screened to evaluate the number of maintenance visits, type of complications, and cost (actual fees for the service) of the maintenance visits. The data were analyzed, and the mean values calculated.

RESULTS

The average number of maintenance visits was 7.7 in the mean observation time of 5.2 years. Replacement of the attachment was the most frequent complication (63%). The average maintenance cost charged to the patient for maintenance was 56.2% ($795) of the initial cost over the average 5.2 years of follow-up. The average total maintenance cost (actual fees for the service) was 95.4% ($1349) of the initial cost over the average of 5.2 years of follow-up. The average maintenance cost adjusted or lost over the 5.2 years follow-up was 39.2%.

CONCLUSIONS

The 5-year costs for the maintenance of mandibular overdentures with a LOCATOR-attachment system were equal to or higher than the initial cost of the treatment. The number of maintenance visits and the cost were higher for patients who were older than 75 years.

Peri-implant mucosal response to implant-supported overdentures: A systematic review and meta-analysis

OBJECTIVES

To systematically review and evaluate the effects of different types of attachments, implant numbers and loading protocols on the peri-implant mucosa of implant-supported overdentures (ISODs).

BACKGROUND

The impact of peri-implant tissue health on the ISOD treatment outcome is unclear, and current evidence is inadequate on this aspect.

MATERIALS AND METHODS

A systematic literature search for randomised controlled trials or prospective studies was conducted in indexed databases from 1995 to April 2020. The focused question was as follows: How does the peri-implant mucosa respond to implant-supported or implant-tissue-supported complete overdentures based on different types of attachments, implant numbers, and loading protocols, in terms of clinical outcomes achieved [plaque index (PI), gingival index (GI), probing pocket depth (PD) and bleeding index (BI)]? A random- or fixed-effects model was applied to measure the significance of standardised mean differences (SMD) of PD between the groups.

RESULTS

Seventeen studies met the eligibility criteria. The SMD for PD between splinted/bar and unsplinted/stud attachments was 0.10 mm (95% CI: -0.27 to 0.47; P = .60) and between 2- and 4-implant groups was 0.15 mm (95% CI: -0.16 to 0.45; P = .34), which were not statistically significant. Significant difference (P = .003) was observed between immediate/early loading and delayed loading (SMD = 0.46 mm [95% CI: 0.16 to 0.75]).

CONCLUSIONS

Probing depth for the immediate loaded implants was significantly higher than for the delayed loading group. No attachment type, implant number or loading protocol seemed to have a clear advantage over the other, in terms of other peri-implant mucosal outcome measures.

Survival rate and clinical evaluation of the implants in implant assisted removable partial dentures: surveyed crown and overdenture

PURPOSE

The purpose of this study was to investigate survival rates of the implants used in implant assisted removable partial dentures (IARPDs).

MATERIALS AND METHODS

The study was conducted on 21 patients who were treated with IARPDs. The mean follow-up period for IARPD patients ranged from 12 to 185 months (mean 47.9 months). A total of 58 implants were used for IARPDs in two different modalities: 41 for surveyed crowns and 17 for overdentures. The survival of implants was determined by clinical and radiographic evaluations considering relevant factors: location, RPD classification, opposing dentition, splinting, and implant diameter.

RESULTS

The survival rate of total 58 implants was 93.1%: 95.1% for implants supporting surveyed crowns and 88.2% for implants used in overdentures. Considering only the implants supporting surveyed crown, regular diameter implants showed a higher survival rate than narrow or wide diameter implants.

CONCLUSION

The survival rate of the implants used in IARPDs was 93.1% (surveyed crown: 95.1%, overdenture: 88.2%).

Complex Rehabilitation for an Adolescent with Ectodermal Dysplasia-A 10-Year Follow-Up

Maxillofacial rehabilitation of patients with ectodermal dysplasia (ED) often presents clinical challenges due to hypodontia and hypoplastic alveolar bone. This clinical report describes a 16-year-old patient suffering from ED who displayed severe hypodontia, maxillary retrusion and thin knife-edge alveolar crest. This patient was treated with distraction osteogenesis and a bone graft harvested from the iliac crest to correct maxillary retrusion and bone insufficiency. Six months later, implants were inserted. Then, implant-supported overdentures were completed. Although a new implant was reinserted during the 10-year follow-up, the results showed that combination surgical treatment achieved a predictable, functional and esthetic outcome in a patient suffering from ED.

Retention of mandibular implant-retained overdentures with two different attachment designs: An in vitro study

STATEMENT OF PROBLEM

Retentive force and loss of retention should be considered when selecting an attachment. Studies that evaluate the retentive force and the effect of repeated cycles of insertion and removal on the TITACH attachment with a metal-to-metal interface are needed.

PURPOSE

The purpose of this in vitro study was to measure the retention of mandibular implant-retained overdentures with 2 different attachment designs before and after 1000 insertion and removal cycles.

MATERIAL AND METHODS

Two dental implants were inserted at the mandibular canine region bilaterally in a completely edentulous model. Sixteen mandibular implant-assisted overdentures were fabricated to form 2 groups, each with a different attachment design. One group received 8 pairs of TITACH attachments, while the other group received 8 pairs of LOCATOR attachments. A cyclic loading machine was used to perform 1000 insertion and removal cycles. A universal testing machine was used to evaluate retentive force before and after insertion and removal cycles. Data were analyzed by using the Mann-Whitney U test and Wilcoxson signed-rank test.

RESULTS

When retentive forces before and after 1000 insertion and removal cycles were compared, the TITACH attachment showed significantly higher retentive force than the LOCATOR (P<.05). However, the LOCATOR attachment showed a significantly lower percentage change in retentive force (P<.05).

CONCLUSIONS

The TITACH attachment group showed favorable initial and final retentive force compared with the Zest Anchor LOCATOR attachment group. However, the LOCATOR attachment group showed favorable lower percentage change in retentive force.

Splinted versus unsplinted overdenture attachment systems - no difference in clinical outcomes

Data sources PubMed/Medline, Scopus and Cochrane databases supplemented by hand searches in the journals; Clinical Oral Implants Research, Journal of Oral Rehabilitation, The Journal of Prosthetic Dentistry, Journal of Prosthodontics and Journal of Dentistry.Study Selection Randomised controlled clinical trials (RCTs), prospective studies with ≥ ten participants and follow-up periods ≥ six months, published in English, and comparing splinted and unsplinted attachment systems within the same study.Data extraction and synthesisTwo investigators independently performed the electronic search; of which one collected the data while the other investigator verified it. A third investigator was involved in cases of disagreement. The Kappa test was also used to determine the inter-examiner agreement. The risk of bias was analysed using the Cochrane Risk of Bias Tool and the Newcastle-Ottawa scale.Results Nine studies were included; six RCTs, two prospective studies and one crossover study, involving the placement of 984 implants in 380 patients and a mean follow-up period of five years. All implants were placed in the mandibular arch. The included studies demonstrated a low or unclear risk of bias. Both splinted and unsplinted attachment systems performed similarly, with no statistically significant differences present in marginal bone loss, complications and implant survival.Conclusions The choice of attachment system does not seem to influence marginal bone loss, the incidence of complications or implant survival in mandibular overdentures.

Multicenter Retrospective Analysis of Implant Overdentures Delivered with Different Design and Attachment Systems: Results Between One and 17 Years of Follow-Up

PURPOSE

To analyze implant and prosthetic survival rates, complications, patient satisfaction, and biological parameters of patients rehabilitated with implant overdentures (IOV) on splinted and nonsplinted implants and different attachment systems, in function for one to 17 years.

METHODS

This retrospective study evaluated data collected from patients rehabilitated with implant overdentures between January 2001 and December 2016 in nine different centers. Outcome measures were implant and prosthetic success rates, mechanical complications, marginal bone loss (MBL), oral health impact profile (OHIP), bleeding on probing, and plaque index.

RESULTS

A total of 581 implants were installed in 194 patients. Patients were followed for a mean period of 60.6 months (range 6⁻206). Eighty-nine patients received 296 low profile attachment (OT Equator), 62 patients received 124 ball attachments, and 43 patients received 107 Locator attachments. In eighty-three patients the implants were splinted with computer aided design/computer aided manufacturing (CAD/CAM) or casted bar. At the last follow-up, 10 implants failed in eight patients. Statistical significance was found for failed prostheses (P = 0.0723) and complications (P = 0.0165), with better values for splinted implants. No statistically significant differences were found in proportion of implant and prosthetic failure (P > 0.05). At a five-year follow-up, proportion of complications (P = 0.0289) and failed prostheses (P = 0.0069) were statistically higher for IOV on Locator attachments. No difference was founded in MBL at one- and two-year follow-up between different attachment systems (P > 0.05). Statistically significant improvement in all the OHIP categories was reported in all the patients, after one year of function.

CONCLUSIONS

Implant overdenture showed high implant and prosthetic survival rates, low complications, high patient satisfaction, and good biological parameters in the long-term follow-up. Splinting the implants may reduce number of mechanical complications. Locator attachments showed higher number of complications. Further studies are needed to confirm these preliminary results.

Splinted and unsplinted overdenture attachment systems: A systematic review and meta-analysis

Splinted and unsplinted overdenture attachment systems have unique advantages and disadvantages. The aim of the present systematic review was to determine the influence of splinted and unsplinted overdenture attachment systems on the marginal bone loss, prosthetic complications and implant survival rate. PubMed/MEDLINE, Scopus and Cochrane databases were searched for articles published up to October 2017, using the following search terms: "overdenture AND attachment OR overdenture AND bar OR overdenture splinted." The PICO question "Do splinted overdenture attachment systems promote better clinical results in comparison to unsplinted systems?" was evaluated. Eligible studies included randomized controlled clinical trials, prospective studies with at least 10 participants and a minimum follow-up of 6 months, and studies published in English that compared splinted and unsplinted attachment systems within the same study. The 95% confidence interval (CI) was considered for all outcomes analysed. After completion of the different steps in the article selection process, nine articles were included in the qualitative and quantitative analyses. A total of 984 implants were placed in 380 patients (mean age: 62.8 years). The meta-analysis demonstrated no statistically significant differences between splinted and unsplinted attachment systems with regard to marginal bone loss (P = .39; MD: -0.11; 95% CI: -0.37 to 0.14), complications (P = .31; RR: 1.26; CI: 0.80-1.99) and implant survival rate (P = .14; RR: 0.37% CI: 0.10-1.36). In addition, splinted and unsplinted overdenture attachment systems achieved similar results with regard to marginal bone loss, prosthetic complications and implant survival rate.