A Prospective Randomized Study on the Immediate Loading of Mandibular Overdentures Supported by One or Two Implants; A 3 Year Follow-Up Report

Impact of loading protocol of a mandibular single implant-supported complete denture on oral health-related quality of life over a period of 5 years: A randomized controlled trial

OBJECTIVES

The aim of the present study was to assess the long-term course of OHRQoL and the impact of the loading protocol in patients receiving a single mandibular implant supporting a complete denture over a period of five years.

METHODS

In this multicenter RCT, a total of 158 edentulous patients were initially included and were randomly allocated immediately after placement of a mandibular midline implant to either immediate loading (IL) or to conventional loading (CL) with submerged healing. The assessment of OHRQoL was performed with the 49-item Oral Health Impact Profile (OHIP) at baseline and 1, 4, 12, 24, and 60 months after loading. At 5-year follow-up, 100 patients (mean age: 69.2 years; 45.0% female) with completed OHIP were available for analyses. A mixed-effects model with patients as random effect and an unstructured covariance matrix was developed to address repeated outcome measurement.

RESULTS

The OHRQoL improved substantially after loading, indicated by a decrease of mean OHIP summary scores from 51.0 points at baseline, by 14.2 (95%-CI: 9.4 - 19.1; p<0.001) points to 37.2 points at 1-month follow-up, and by continuous improvement to 20.4 OHIP points at final follow-up. Considering constant treatment effects, the loading protocol had no significant effect on OHIP scores (-3.7, 95%-CI: -9.4 - 2.2; p = 0.204). Time effect was statistically significant with -0.21 (95%-CI: -0.28 - -0.15; p<0.001) points per month.

CONCLUSION

Both the immediate and conventional loading of a single mandibular midline implant supporting a complete denture offer long-lasting high levels of OHRQoL, with no significant or clinically relevant long-term differences.

CLINICAL SIGNIFICANCE

The study firstly presents long-term data for OHRQoL by investigating the loading protocol of single mandibular implant-supported complete dentures. Since immediate loading has been associated with a reduced implant survival rate for this concept, information on patient benefits is essential for evidence-based decision making.

Single Implant-Retained Mandibular Overdentures: A Literature Review

The absence of teeth, known as edentulism, poses considerable obstacles in prosthodontic care and greatly affects a person's well-being. Conventional complete dentures frequently lead to problems like instability and insufficient retention, especially in the lower jaw. Fortunately, the introduction of dental implants has transformed the way we approach edentulous patients, as they now offer support and enhanced retention for removable prostheses, thus revolutionizing their treatment. While a consensus exists on using two implants for retaining mandibular overdentures, the associated cost may be prohibitive for economically disadvantaged individuals. As a solution, the concept of single implant-retained mandibular overdentures has emerged, catering to individuals with limited financial resources and complete tooth loss. This review explores the efficacy and suitability of the single implant overdenture approach, along with an overview of treatment options for edentulous patients, including traditional dentures, tooth-supported overdentures, and implant-supported overdentures. The preservation of bone, improvements in functional abilities, and psychological benefits associated with overdentures are discussed. Moreover, various classifications and prosthetic options for implant overdentures, specifically for mandibular cases, are presented. This literature review aims to provide a comprehensive understanding of possible treatment options and focus on the single implant-retained mandibular overdenture approach and its implications in prosthodontic rehabilitation for edentulous patients.

Single-Implant Overdentures Retained by a Novel Attachment: A Mixed Methods Crossover Randomized Clinical Trial

INTRODUCTION

Single-implant mandibular overdentures (SIMOs) are one of the least invasive implant treatments for edentulism. The new Novaloc attachment system can improve the clinical performance of implant-retained overdentures but has not been tested for SIMOs.

OBJECTIVES

To compare Novaloc and a gold standard system (Locator) for SIMOs in an edentate elderly population in terms of patient-reported outcomes and device- and treatment-related complications.

METHODS

In this single-center crossover randomized clinical trial (RCT), 10 edentulous participants received an implant in the lower midline and had their lower complete dentures converted to SIMOs. The participants received each attachment system for 3 mo in a randomized order, followed by measurement of patient satisfaction and oral health-related quality of life via the McGill Denture Satisfaction Questionnaire and the Oral Health Impact Profile for Edentulous People questionnaire, respectively. Complications were registered throughout the RCT. Patients were interviewed for their experiences with SIMOs and preference for one of the attachment systems. Quantitative analysis employed mixed linear models and chi-square tests (α = 0.05), whereas interview data underwent thematic analysis and, in turn, integration into quantitative data (mixed methods explanatory design).

RESULTS

All 10 randomized participants completed the trial. Mean ± SD general satisfaction was 92% ± 8% with Novaloc versus 85% ± 13% with Locator (mean difference, 9%; 95% CI, 1% to 17%). For specific McGill Denture Satisfaction Questionnaire items, only denture stability was significantly increased for Novaloc. Seven participants preferred Novaloc over Locator at the end of the RCT (chi-square, P = 0.045). No difference was found between the attachments in terms of oral health-related quality of life based on the Oral Health Impact Profile for Edentulous People and complications. Thematic analysis revealed high patient satisfaction with SIMOs, with denture stability the main criterion for their satisfaction and attachment preference.

CONCLUSION

Among elderly edentulous patients wearing SIMOs, Novaloc led to increased patient satisfaction and preference. Better patient-perceived denture stability may explain this result. The attachment systems exhibited similar short-term maintenance needs.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03126942 (first registered on April 13, 2017). Secondary identifiers: A03-M07-17A (McGill University, Institutional Review Board) and 2018-3873 (McGill University Health Centre, Research Ethics Board).

KNOWLEDGE TRANSFER STATEMENT

The results of this mixed methods study can be used by clinicians when choosing which attachment system to use for SIMOs. Results suggest that edentulous patients prefer attachments with a better-defined seating position, such as that of the Novaloc system, as opposed to the nylon matrix on metallic abutment of the Locator system.

Prosthodontic outcomes of mandibular overdenture treatment with one or two implants: 4-year results of a randomized clinical trial

OBJECTIVE

To assess the incidence of prosthodontic maintenance events and complications during 4 years of follow-up after mandibular overdenture treatment with one or two implants.

METHODS

Participants received one or two implants inserted in the midline (1-IOD group) or the lateral incisor-canine area bilaterally (2-IOD group). Implants were loaded with an early loading protocol after 3 weeks. Programmed recall visits were scheduled at the 6-, 12-, 36-, and 48-month follow-ups and nonprogrammed visits in case of prosthodontic complaints. The type of maintenance was registered, and the final treatment outcome was classified as successful, surviving, unknown, dead, repair, or retreatment.

RESULTS

Forty-seven participants, mean age 65.4 ± 8.6, 74.5% female, were included (1-IOD = 23; 2-IOD = 24) and 44 completed the 4-year follow-up. A total of 159 prosthodontic maintenance events occurred and 89 in unscheduled visits. The most common event was the need for minor modifications of the denture base due to sore spots in the oral mucosa (n = 56 in 31 patients), matrix activation (n = 54 in 34 patients), and overdenture fracture (n = 25 in 18 patients). A "successful" or "surviving" outcome could be attributed to 57.5% of cases, whereas 38.3% needed repair. No significant differences in the incidence of prosthodontic events or treatment outcomes were found between the two groups.

CONCLUSIONS

Findings show that 1-IODs perform similar to 2-IODs when considering the incidence of fractures and the need for prosthodontic maintenance, including adjustments of the overdenture and the attachment system.

Patient satisfaction and crestal bone changes with one-piece and two-piece single implant-retained mandibular overdenture: A randomized controlled clinical study

PURPOSE

The present study was done to assess patient satisfaction and crestal bone changes with one-piece and two-piece single implant-retained mandibular overdentures (SIMOs).

METHODS

The participants included in Group 1 (n=12) received one-piece SIMOs; the participants in Group 2 (n=12) received two-piece SIMOs.Scheduled follow-ups were done at 1 month and 1 year after implant placement. Patient satisfaction and crestal bone changes were evaluated. The data obtained were analyzed statistically with independent Student t-test.

RESULTS

Visual analogue scale (VAS) score for patient satisfaction with one-piece and two-piece SIMOs were statistically significant at 1-year of follow-up. The patient satisfaction level on the VAS score increased (38.1 to 51.1) with group one-piece SIMOs and two-piece SIMOs (36.6 to 46.8) at baseline to 1 month (P=0.13). The patient satisfaction level increased (38.1 to 56.6) with group one-piece SIMOs and two-piece SIMOs (36.6 to 52.2) at baseline to 1 year (P=0.03). At the 1 year follow-ups, group 1 had mean crestal bone loss of 0.80 ± 0.49 mm and group 2 had 1.24 ± 0.90 mm (P=0.16). Crestal bone loss was greater in the two-piece SIMOs group at 1 month and 1 year follow-ups, but statistically it was insignificant.

CONCLUSIONS

One-piece SIMOs seemed to be a viable treatment option with increased patient satisfaction on a VAS. Crestal bone loss was greater in the patients with two-piece SIMOs during follow-up. One-piece SIMOs was comparatively simple with less invasive procedures and needed fewer components,so considerable number of patients requiring implant retained dentures could be benefited.

Patient-reported outcomes with immediate-loaded two-implant-supported mandibular overdentures: Results of a 5-year prospective study

Background/purpose

Few studies have comprehensively assessed long-term patient-reported outcomes for overdentures supported by two immediate implants. The purpose of the study was to evaluate patient-reported outcomes of immediately loaded two-implant-supported overdentures retained by ball attachments over a 5-year evaluation period.

Material and methods

Nineteen participants with edentulous mandibles were provided with immediately loaded two-unsplinted-implant-supported overdentures retained by ball attachments. The participants completed the Japanese version of the Oral Health Impact Profile (OHIP)-EDENT-19 and the Patient's Denture Assessment (PDA). Additionally, patient satisfaction was measured by a 100-mm visual analog scale (VAS). Measurements were performed at baseline, and at 1 and 5 years following implant surgery.

Results

Seventeen participants and 14 participants were evaluated at the 1-year and 5-year assessment, respectively. Considering the OHIP-EDENT-19, there was a significant decrease in the total (p = 0.046), “functional limitation” (p = 0.021), and “physical disability” (p = 0.034) scores at 1 year and the total (p = 0.045) and “physical disability” (p = 0.024) scores at 5 years following surgery, compared to the baseline scores. Considering the PDA, there was a significant increase in the “function” (p = 0.038) and “lower denture” (p = 0.003) scores at 1 year and the “function” (p = 0.032), “lower denture” (p = 0.008), and “esthetic and speech” (p = 0.043) scores at 5 years following surgery, compared to the baseline scores. Patient satisfaction at 1 year following surgery was significantly greater than that at baseline (p = 0.005).

Conclusion

Immediately loaded two-unsplinted-implant-supported overdentures retained by ball attachments improved the oral health-related quality of life and self-assessment of dentures by the patients up to 5 years following implant surgery.

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.

Comparison of ridge resorption and patient satisfaction in single implant-supported mandibular overdentures with conventional complete dentures: A randomised pilot study

Purpose

To compare ridge resorption (RR) and patient satisfaction in single implant-supported mandibular overdentures (SIMO) with conventional complete dentures (CCD) over a period of one year.

Material and methods

This prospective, randomized trial enrolled 30 completely edentulous participants following inclusion and exclusion criteria. The study was completed by 28 participants. Rehabilitation of 14 participants was done by using SIMO (group I) and CCD (group C) each according to randomization chart. For both the groups, RR was computed in millimeters from residual ridge height measured by using orthopantogram at 6 months (T1), 9 months (T2), and 12 months (T3) at 3 anatomic locations: maxillary posterior (L1), maxillary anterior (L2), and mandibular posterior (L3). Patient satisfaction was evaluated by using Geriatric Oral Health Assessment Index Hindi version (GOHAI-Hi) at 1week and 12 months after denture delivery.

Results

At 12 months, minimum RR was observed at L2 of group I (0.62 ​± ​0.20 ​mm) and maximum RR was observed at L3 of group C (1.04 ​± ​0.15 ​mm). Comparison of ridge resorption between group I and group C was statistically significant at T3 (P ​= ​.001 for L1, P ​= ​.006 for L2, and P ​= ​.028 for L3). At T3, in group I, RR was more at L3 than L2 region (P ​= ​.011) and L1 region (P ​= ​.015). Statistically significant difference of GOHAI-Hi scores was observed between group I and group C at end of 12 months (P ​= ​.003).

Conclusions

SIMO cause less RR and higher patient satisfaction as compared to CCD and can be recommended with higher predictability of success than CCD.

5-year randomized multicenter clinical trial on single dental implants placed in the midline of the edentulous mandible

OBJECTIVES

This multicenter randomized controlled clinical trial was conducted to investigate whether the loading protocol of single dental implants placed in the midline of edentulous mandibles will influence the implant survival or prosthetic maintenance.

MATERIALS AND METHODS

In total, 158 patients were randomly assigned either to the immediate loading group (n = 81) or to the delayed loading group (n = 77). All implants were loaded with an overdenture retained by a ball attachment.

RESULTS

After 5 years, 102 patients attended the follow-up investigation. Immediately loaded single implants in the midline of the edentulous mandible revealed a statistically significant lower survival rate than implants loaded conventionally over an observation period of 5 years. In the immediate loading group, 9 implants failed within the first three months of implant loading. No further implant loss was recorded for this group. Two implants failed in the delayed loading group, whereas one implant had to be removed during second-stage surgery and the second five years after implant loading. Non-inferiority of the survival rate of the midline implant of the immediate loading group, compared with the delayed loading group, could not be shown (p = .79, CI immediate loading: 74.9%; 100.0%, CI delayed loading: 73.0%; 100.0%). The observed difference in implant survival between the two treatment groups over time was statistically significant.

CONCLUSIONS

The results of the present study indicate that immediate loading of a single mandibular implant in the edentulous mandible should be considered only in exceptional cases.

Influence of Insertion Torque on Clinical and Biological Outcomes before and after Loading of Mandibular Implant-Retained Overdentures in Atrophic Edentulous Mandibles

Aim

To evaluate the influence of primary insertion torque (IT) values of narrow dental implants on the peri-implant health, implant stability, immunoinflammatory responses, bone loss, and success and survival rates.

Methods

Thirty-one edentulous patients received two narrow implants (2.9x10mm, Facility NeoPoros) to retain mandibular overdentures. The implants were categorized in four groups according to their IT: (G1) IT > 10 Ncm; (G2) IT ≥ 10Ncm and ≤ 30 Ncm; (G3) IT >30Ncm and < 45Ncm; (G4) IT ≥ 45Ncm, and all implants were loaded after 3 months of healing. The following clinical outcomes were evaluated 1, 3, 6, and 12 months after implant insertion: (i) peri-implant tissue health (PH), gingival index (GI), plaque index (PI), calculus presence (CP), probing depth (PD), and bleeding on probing (BOP); (ii) implant stability quotient (ISQ) by resonance frequency analysis; and (iii) IL-1β and TNF-α concentration in the peri-implant crevicular fluid. The marginal bone level (MBL) and changes (MBC) were evaluated. The Chi² test, Kruskal-Wallis test, mixed-effects regression analysis, and the Kendall rank correlation coefficient were used for statistical analysis (α = 5%).

Results

G1 presented the highest PD at all evaluated periods. G2 presented higher PI at month 6 and 12. G4 showed increased GI at month 3 and 12 and more CP at month 1 (p=.003). G2 and G4 had higher ISQ values over the study period, while those from G1 and G3 presented lower ISQ values. The IL-1β concentration increased until month 12 and was independent of IT and bone type; G4 had a higher IL-1β concentration in month 3 than the other groups (p=.015). The TNF-α release was negatively correlated with IT, and TNF-α release was highest in G1 at month 12. The MBL immediately after surgery and the MBC at month 12 were similar between the groups, and G4 presented a positive MBC at month 12. The survival and success rates were 75% for G1, 81.3% for G2, 64.3% for G3, and 95% for G4.

Conclusion

The IT did not influence the clinical outcomes and the peri-implant immunoinflammatory responses and was weakly correlated with the narrow dental implants primary stability. The observed success rates suggest that the ideal IT for atrophic fully edentulous patients may deviate from the standardized IT of 32 Ncm.

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.

Single-implant overdentures retained by the Novaloc attachment system: study protocol for a mixed-methods randomized cross-over trial

BACKGROUND

Overdentures retained by a single implant in the midline have arisen as a minimal implant treatment for edentulous mandibles. The success of this treatment depends on the performance of a single stud attachment that is susceptible to wear-related retention loss. Recently developed biomaterials used in attachments may result in better performance of the overdentures, offering minimal retention loss and greater patient satisfaction. These biomaterials include resistant polymeric matrixes and amorphous diamond-like carbon applied on metallic components. The objective of this explanatory mixed-methods study is to compare Novaloc, a novel attachment system with such characteristics, to a traditional alternative for single implants in the mandible of edentate elderly patients.

METHODS/DESIGN

We will carry out a randomized cross-over clinical trial comparing Novaloc attachments to Locators for single-implant mandibular overdentures in edentate elderly individuals. Participants will be followed for three months with each attachment type; patient-based, clinical, and economic outcomes will be gathered. A sample of 26 participants is estimated to be required to detect clinically relevant differences in terms of the primary outcome (patient ratings of general satisfaction). Participants will choose which attachment they wish to keep, then be interviewed about their experiences and preferences with a single implant prosthesis and with the two attachments. Data from the quantitative and qualitative assessments will be integrated through a mixed-methods explanatory strategy. A last quantitative assessment will take place after 12 months with the preferred attachment; this latter assessment will enable measurement of the attachments' long-term wear and maintenance requirements.

DISCUSSION

Our results will lead to evidence-based recommendations regarding these systems, guiding providers and patients when making decisions on which attachment systems and implant numbers will be most appropriate for individual cases. The recommendation of a specific attachment for elderly edentulous patients may combine positive outcomes from patient perspectives with low cost, good maintenance, and minimal invasiveness.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03126942 . Registered on 13 April 2017.

Survival and Complications of Single Dental Implants in the Edentulous Mandible Following Immediate or Delayed Loading: A Randomized Controlled Clinical Trial

It was the aim of this 24-mo randomized controlled clinical trial to investigate whether the survival of a single median implant placed in the edentulous mandible to retain a complete denture is not compromised by immediate loading. Secondary outcomes were differences in prosthetic complications between the loading principles. Each of the 158 patients who received an implant was randomly assigned to the immediate loading group (n = 81) or the delayed loading group (n = 77). Recall visits were performed 1 mo after implant placement (for only the delayed loading group) and 1, 4, 12, and 24 mo after implant loading. Nine implants failed in the immediate loading group, all within the first 3 mo of implant loading, and 1 implant failed in the delayed loading group prior to loading. Noninferiority of implant survival of the immediate loading group, as compared with the delayed loading group, could not be shown (P = 0.81). Consistent with this result, a secondary analysis with Fisher exact test revealed that the observed difference in implant survival between the treatment groups was indeed statistically significant (P = 0.019). The most frequent prosthetic complications and maintenance interventions in the mandible were retention adjustments, denture fractures, pressure sores, and matrix exchanges. There was only 1 statistically significant difference between the groups regarding the parameter “fracture of the denture base in the ball attachment area” (P = 0.007). The results indicate that immediate loading of a single implant in the edentulous mandible reveals inferior survival than that of delayed loading and therefore should be considered only in exceptional cases (German Clinical Trials Register: DRKS00003730).

Mandibular complete denture versus single-implant overdenture: a systematic review of patient-reported outcomes

The single-implant mandibular overdenture (SIMO) has been proposed as an alternative for edentulous patients who are poorly adapted to their dentures due to low retention and stability of the conventional mandibular complete denture (CD). However, there is a lack of evidence regarding the effectiveness of SIMO, which can be measured by examining patient perception of treatment effects. The aim of this systematic review was to assess the comparative results of CD and SIMO treatments using patient-reported outcome measures. A literature search was carried out in PubMed, Scopus and Cochrane Central databases. The search included studies published up to July 2017. The focus question was: 'Do single-implant mandibular overdentures improve patient-reported outcomes compared to conventional complete dentures in edentulous patients?' Eligible studies were randomised clinical trials (RCT) and prospective studies. After initial screening for eligibility and full-text analysis, 11 studies were included for data extraction and quality assessment (five parallel-group RCTs, two crossover RCTs and four prospective studies). All studies reported marked improvement in satisfaction with the dentures and quality of life measures after SIMO treatment, irrespective of variations in implant treatment protocols and retention systems. Methodological considerations revealed a lack of evidence from RCTs on the comparative effectiveness of the two treatment strategies. Hence, although available evidence suggests considerable improvement in patient-reported outcomes following the insertion of a single implant to retain a mandibular denture, further well-designed comparative studies between SIMO and CD are required to improve the level of evidence and to support the indication of SIMO treatment in routine practice.

An International Survey among Prosthodontists of the Use of Mandibular Implant-Supported Dental Prostheses

PURPOSE

To evaluate the use of implant-supported overdentures (IOD) and implant-supported fixed dental prostheses (IFDP) in patients with edentulous mandibles among international prosthodontists.

MATERIALS AND METHODS

A questionnaire was sent by e-mail to all clinically active prosthodontists in the International College of Prosthodontists with questions related to implant treatment of the edentulous mandible performed in 2015.

RESULTS

One hundred and sixteen prosthodontists from 33 countries responded to the questionnaire. The vast majority of the responding prosthodontists was faculty or worked in private practice, and the great majority had performed treatment with mandibular implant-supported dental prostheses; however, two thirds of the respondents reported that <20% of the implant patients in their clinic had received treatment related to edentulous mandibles. The majority reported using 2 implants (84%), while 13% used 4 for overdenture retention. There were great variations regarding retention systems used for mandibular IODs; the most common was individual Locator attachments. Cost was considered the most common reason to choose mandibular IOD, There was a wide variation of materials used for mandibular IFDPs. The most common combination included milled titanium frameworks and acrylic resin teeth.

CONCLUSIONS

This survey, completed by 116 prosthodontists from 33 countries, showed that implant treatment for edentulous mandibles is common, but there was great variation among the respondents regarding amount of treatments performed, design, and materials used for the implant prostheses.

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.

Implant survival in 1- versus 2-implant mandibular overdentures: a systematic review and meta-analysis

OBJECTIVE

This systematic review was performed to compare the survival of 1- vs. 2-implant overdentures (IODs) in the edentulous mandible.

MATERIALS AND METHODS

Manual and electronic database (PubMed, EMBASE and CENTRAL) searches were performed to identify scientific articles, published in English, reporting on mandibular IODs utilizing unsplinted attachments. Studies were included if they were prospective human studies reporting on two-piece microrough surface implants with a diameter ≥3 mm. Data were extracted by two independent investigators, and an overall inter-investigator kappa score was calculated. A meta-analysis was performed on the included comparative studies.

RESULTS

The search shortlisted 30 prospective studies for data extraction and statistical analysis. The included studies comprised of only two randomized controlled trials (RCTs) comparing 1- vs. 2-IODs, and a further 28 prospective studies. The kappa score calculated was between 0.86 and 1 for the various parameters. One RCT favored 1-IODs (RD: 0.08, 95% CI: 0.01, 0.14) while the other favored 2-IODs (RD:-0.04, 95% CI: -0.27, 0.19). However, the overall random effects model did not reveal a significant risk difference (RD) for implant failure between the two interventions (I(2) = 36.6%, P = 0.209; RD: 0.05, 95% CI: -0.07, 0.18).

CONCLUSIONS

The results of this meta-analysis conclude that the postloading implant survival of 1-IODs is not significantly different from 2-IODs. However, the existing scientific evidence in the literature in terms of prospective comparative studies is scarce. Hence, before recommending the 1-IOD as a treatment modality, long-term observations are needed and a larger range of functional, prosthodontic, and patient-centered outcome measures should be considered.

Immediate loading of two freestanding implants placed by computer-guided flapless surgery supporting a mandibular overdenture with magnetic attachments

PURPOSE

The present article describes a novel clinical procedure for mandibular overdentures supported by two freestanding implants loaded immediately after placement via computer-guided flapless surgery.

METHODS

A conventional acrylic complete denture was fabricated, and CT scans obtained using the denture as a radiographic guide. Preoperative computer-assisted planning was performed using commercially available software, permitting simulation of implant placement at optimal positions. Using simulation data, a surgical guide was manufactured and used during surgery. The surgical guide was placed and local anesthesia injected for drilling of anchor pins to stabilize the surgical guide. The drilling protocol for each osteotomy site achieved an insertion torque greater than 35 Ncm. Immediately after implant placement, a keeper of the magnetic attachment was connected to each implant, and the magnetic assembly incorporated into the denture. The mucosal surface of the denture around the magnet was relieved to avoid excessive tissue pressure. The patients were instructed to wear the denture in place continually for the following 7 days. After six months of healing and follow-up, a final denture with a metal framework may be fabricated if necessary.

CONCLUSION

A novel treatment protocol for immediately loaded implant-supported mandibular overdentures is described in detail. The protocol ensures secure precise and safe implant placement, successful osseointegration, and immediate improvement of oral health-related quality of life for patients with unstable complete dentures.

Improving masticatory performance, bite force, nutritional state and patient's satisfaction with implant overdentures: a systematic review of the literature

Oral function with removable dentures is improved when dental implants are used for support. A variety of methods is used to measure change in masticatory performance, bite force, patient's satisfaction and nutritional state. A systematic review describing the outcome of the various methods to assess patients' appreciation has not been reported. The objective is to systematically review the literature on the possible methods to measure change in masticatory performance, bite force, patient's satisfaction and nutritional state of patients with removable dentures and to describe the outcome of these. Medline, Embase and The Cochrane Central Register of Controlled Trials were searched (last search July 1, 2014). The search was completed by hand to identify eligible studies. Two reviewers independently assessed the articles. Articles should be written in English. Study design should be prospective. The outcome should be any assessment of function/satisfaction before and at least 1 year after treatment. Study population should consist of fully edentulous subjects. Treatment should be placement of any kind of root-form implant(s) to support a mandibular and/or maxillary overdenture. Fifty-three of 920 found articles fulfilled the inclusion criteria. A variety of methods was used to measure oral function; mostly follow-up was 1 year. Most studies included mandibular overdentures, three studies included maxillary overdentures. Implant-supported dentures were accompanied by high patient's satisfaction with regard to denture comfort, but this high satisfaction was not always accompanied by improvement in general quality of life (QoL) and/or health-related QoL. Bite force improved, masseter thickness increased and muscle activity in rest decreased. Patients could chew better and eat more tough foods. No changes were seen in dietary intake, BMI and blood markers. Improvements reported after 1 year apparently decreased slightly with time, at least on the long run. Treating complete denture wearers with implants to support their denture improves their chewing efficiency, increases maximum bite force and clearly improves satisfaction. The effect on QoL is uncertain, and there is no effect on nutritional state.

Implant and root supported overdentures - a literature review and some data on bone loss in edentulous jaws

PURPOSE

To present a literature review on implant overdentures after a brief survey of bone loss after extraction of all teeth.

MATERIALS AND METHODS

Papers on alveolar bone loss and implant overdentures have been studied for a narrative review.

RESULTS

Bone loss of the alveolar process after tooth extraction occurs with great individual variation, impossible to predict at the time of extraction. The simplest way to prevent bone loss is to avoid extraction of all teeth. To keep a few teeth and use them or their roots for a tooth or root-supported overdenture substantially reduces bone loss. Jaws with implant-supported prostheses show less bone loss than jaws with conventional dentures. Mandibular 2-implant overdentures provide patients with better outcomes than do conventional dentures, regarding satisfaction, chewing ability and oral-health-related quality of life. There is no strong evidence for the superiority of one overdenture retention-system over the others regarding patient satisfaction, survival, peri-implant bone loss and relevant clinical factors. Mandibular single midline implant overdentures have shown promising results but long-term results are not yet available. For a maxillary overdenture 4 to 6 implants splinted with a bar provide high survival both for implants and overdenture.

CONCLUSION

In edentulous mandibles, 2-implant overdentures provide excellent long-term success and survival, including patient satisfaction and improved oral functions. To further reduce the costs a single midline implant overdenture can be a promising option. In the maxilla, overdentures supported on 4 to 6 implants splinted with a bar have demonstrated good functional results.