Five‐year study of mandibular overdentures on stud abutments: Clinical outcome, patient satisfaction and prosthetic maintenance—Influence of bone resorption and implant position

Oral health-related quality of life in implant-supported rehabilitations: a prospective single-center observational cohort study

BACKGROUND

Oral Health-Related Quality of Life (OHRQoL) is a comprehensive concept covering daily comfort, self-esteem, and satisfaction with oral health, including functional, psychological, and social aspects, as well as pain experiences. Despite abundant research on OHRQoL related to oral diseases and hygiene, there is limited data on how patients perceive changes after implant-prosthetic rehabilitation. This study aimed to evaluate OHRQoL and aesthetic perception using OHIP-14 and VAS scales respectively, before (baseline-TB), during (provisional prostheses-TP), and after (definitive prostheses-TD) implant-prosthetic rehabilitation. It also explored the impact of biological sex, substitution numbers, and aesthetic interventions on OHRQoL and VAS scores, along with changes in OHIP-14 domains.

METHODS

A longitudinal prospective single-center observational cohort study was conducted with patients requiring implant-prosthetic rehabilitation. Quality of life relating to dental implants was assessed through the Italian version of Oral Health Impact Profile-14 (IOHIP-14), which has a summary score from 14 to 70. Patients' perceived aesthetic was analyzed through a VAS scale from 0 to 100. Generalized Linear Mixed Effect Models, Linear Mixed Effect Models, and Friedman test analyzed patient responses.

RESULTS

99 patients (35 males, 64 females) aged 61-74, receiving various prosthetic interventions, were enrolled. Both provisional and definitive prosthetic interventions significantly decreased the odds of a worse quality of life compared to baseline, with odds ratios of 0.04 and 0.01 respectively. VAS scores increased significantly after both interventions, with estimated increases of 30.44 and 51.97 points respectively. Patient-level variability was notable, with an Intraclass Correlation Coefficient (ICC) of 0.43. While biological sex, substitution numbers, and aesthetic interventions didn't significantly affect VAS scores, OHRQoL domains showed significant changes post-intervention.

CONCLUSIONS

These findings support the effectiveness of implant-prosthetic interventions in improving the quality of life and perceived aesthetics of patients undergoing oral rehabilitation. They have important implications for clinical practice, highlighting the importance of individualized treatment approaches to optimize patient outcomes and satisfaction in oral health care.

Influence of implant distribution on the biomechanical behaviors of mandibular implant-retained overdentures: a three-dimensional finite element analysis

OBJECTIVE

To assess stress distribution in peri-implant bone and attachments of mandibular overdentures retained by small diameter implants, and to explore the impact of implant distribution on denture stability.

METHODS

Through three-dimensional Finite Element Analysis (3D FEA), four models were established: three models of a two mandibular implants retained overdenture (IOD) and one model of a conventional complete denture (CD). The three IOD models consisted of one with two implants in the bilateral canine area, another with implants in the bilateral lateral incisor area, and the third with one implant in the canine area, and another in the lateral incisor area. Three types of loads were applied on the overdenture for each model: a 100 N vertical load and a inclined load on the left first molar, and a100N vertical load on the lower incisors. The stress distribution in the peri-implant bone, attachments, and the biomechanical behaviors of the overdentures were analyzed.

RESULTS

Despite different distribution of implants, the maximum stress values in peri-implant bone remained within the physiological threshold for all models across three loading conditions. The dispersed implant distribution design (implant in the canine area) exhibited the highest maximum stress in peri-implant bone (822.8 µe) and the attachments (275 MPa) among the three IOD models. The CD model demonstrated highest peak pressure on mucosa under three loading conditions (0.8188 Mpa). The contact area between the denture and mucosa of the CD model was smaller than that in the IOD models under molar loading, yet it was larger in the CD model compared to the IOD model under anterior loading. However, the contact area between the denture and mucosa under anterior loading in all models was significantly smaller than those under molar loading. The IOD in all three models exhibited significantly less rotational movement than the complete denture. Different implant positions had minimal impact on the rotational movement of the IOD.

CONCLUSION

IOD with implants in canine area exhibited the highest maximum stress in the peri-implant bone and attachments, and demonstrated increased rotational movement. The maximum principal stress was concentrated around the neck of the small diameter one-piece implant, rather than in the abutment. An overdenture retained by two implants showed better stability than a complete denture.

Conventional maxillary denture versus maxillary implant-supported overdenture opposing mandibular implant-supported overdenture: Patient's satisfaction

OBJECTIVES

This study sought to determine the impact of age, gender, and use of maxillary implant-supported overdenture (UISOD) versus conventional denture (CMD) opposing mandibular implant-supported overdenture (LISOD) and the number of years the patient has used their prosthesis on the ratings of satisfaction. This study aimed to assess the long-term influence of different factors on patients' satisfaction with LISODs needing a maxillary prosthesis, helping dentists choose a treatment pathway that leads to a higher satisfaction rate.

MATERIAL AND METHODS

This cross-sectional study included 84 participants. They were treated with LISOD opposing either CMD or UISOD from 2015 to 2020. They were all eligible to participate in the study. An oral health impact profile (OHIP-14) questionnaire was given to each patient and filled out by them. OHIP-14 scores were gathered and went under statistical analysis with PASS-11 software to determine the relationship between patients' satisfaction with the scores.

RESULTS

Age and gender had no significant influence on how satisfied patients were. Patients with maxillary overdentures showed more satisfaction than the CMD group (p < .05). Moreover, patients' satisfaction decreased with increasing years of prostheses usage (p < .05).

CONCLUSIONS

This study demonstrated that satisfaction is related to the type of maxillary prosthesis (conventional or implant-supported) used opposing LISODs and the number of years the patient had used the prostheses.

Five years clinical outcome of maxillary mini dental implant overdenture treatment: A prospective multicenter clinical cohort study

BACKGROUND

The long-term clinical outcome of mini dental implants (MDIs) to support an overdenture is underreported especially in severely atrophic maxillae and when installed flaplessly.

PURPOSE

The current report is a 5-years follow-up of the previously published 2- and 3-years clinical outcome of MDIs supporting a maxillary overdenture in narrow alveolar ridges. MDI survival, marginal bone level, peri-implant health, technical complications, and oral health related quality of life (OHIP) and respective changes over time are reported.

MATERIALS AND METHODS

Subjects aged 50 years or older, in need of improvement of maxillary denture retention, were included. The MDIs were 2.4 mm diameter one-piece tapered implants, Class 4 pure Titanium, and lengths 10 or 11.5 mm. Under local anesthesia, 5-6 MDIs were placed in atrophic maxillae with a free-handed flapless approach. One week postoperative the denture was adapted with a retentive soft reliner. The final prosthetic connection was established after 6 months with a metal-reinforced horse-shoe denture. Clinical outcome after 5 years was assessed with probing pocket depts (PPD), bleeding on probing (BoP), and additional cone beam computed tomography (CBCT) MDI bone level measurements were performed. Oral Health-Related Quality of Life (OHRQoL) investigated with OHIP-14 was assessed preoperative, during provisional loading, and after final prosthetic connection up to 5 years.

RESULTS

Initially, 31 patients (14 females and 17 males) with mean age 62.30 underwent treatment. In the provisional loading interval, 16 patients encountered 32/185 MDIs failures, resulting in a failure of 17.3%; 170 MDIs were functionally loaded in 29 patients. Additionally, 14 implants were lost in three patients, all of whom had had already previous failures. Reimplantation of 17 MDIs were performed during the provisional loading and 2 MDI after functional loading. After 5 years, the absolute implant failure rate was 46/204 (22.5%), corresponding to a cumulative failure rate of 23.2%. Prosthetic failure was observed in four patients due to implant loss and in two patients related to excessive one-piece implant ball attachment wear, making the 5-years prosthetic success 80.0%. The mean PPD and absence/presence of BoP for 149 implants at 5 years was 4.3 and 0.2 mm, respectively. Average mesial-distal-vestibular-palatal bone loss in the interval 2-5 years was 0.08 mm. No statistically significant difference in marginal MDI bone loss between male or female (p = 0.835), smoking and nonsmoking (p = 0.666) was observed. The five-years total measured CBCT interdental bone level (mesial and distal) correlates with the 5-years PPD (Pearson 0.434; p = 0.01). After 5 years, OHRQoL with the treatment procedure was assessed in 27/31 participants. Decreasing mean total OHIP-14 scores with improved OHRQoL, was observed in 27/31 participants, with values of 21.3 at baseline to 15.6 at the time of provisional loading which significantly (p = 0.006) decrease to 7.3 at the final prosthetic connection. The next 3-5 years further decrease was observed with 6.5 and 4.96, respectively.

CONCLUSIONS

Maxillary MDIs for overdentures are an accessible and acceptable treatment option. Although after 5 years between one fifth and one fourth of the MDIs were lost, prosthetic success remains 80.0% and high OHRQoL could be achieved.

Implant-Supported Overdentures: Current Status and Preclinical Testing of a Novel Attachment System

Numerous attachment systems exist for implant-supported overdentures, with each having specific limitations in terms of retention, cost, wear, maintenance and cleanability. A retrospective analysis of patients restored with implant-supported overdentures using bars, telescopic crowns and Locator-type attachments was performed and the patients were interviewed. An in vitro strain gauge study compared telescopic crowns, Locator-type attachments and a novel flexible attachment system employing a shape memory alloy (NiTi) with respect to peri-implant strain development during insertion, loading and removal of an overdenture. A significantly lower number of attachment-related complications was observed in bars as compared to telescopic crowns (p = 0.00007) and Locator-type attachments (p = 0.00000), respectively. Greater overall patient satisfaction was noted in bar-retained restorations while Locator-type attachments led to lower levels of satisfaction regarding prosthesis retention. In vitro, telescopic crowns caused maximum strain development during prosthesis insertion and loading, while during removal this was observed in Locators with white retentive inserts. NiTi attachments caused significantly lower strain development during insertion as compared to telescopic crowns (p = 0.027). During loading, NiTi attachments caused significantly lower strain development than Locators with blue retentive inserts (p = 0.039). During removal, NiTi attachments caused significantly less strain development as compared to Locators with white retentive inserts (p = 0.027). Positional discrepancies between male and female attachment parts affected the retention and reaction force between both components, which may be minimized by using the novel NiTi attachment system. This may be beneficial in terms of component wear and implant loading.

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.

Implant-Retained Mandibular Overdentures: Patient-Related Outcome Measurements after Seven Years of Function

Denture wearers often complain about jeopardized function and reduced quality of life due to lack of prosthesis’ retention. Implant-retained mandibular overdentures, on two non-connected implants (2IOD) are well-proven solutions to overcome these issues. We prospectively assessed 69 patients and scrutinized clinical records until at least seven years of function. Thirty-six were retained on Locator^® Abutments (LA) and thirty-tree on Ball Abutments (BA). Both systems were compared regarding the type, amount, and total cost of required maintenance. One implant was lost, yielding 98.7% survival after seven years. In total, 438 technical issues occurred: 121 (27.35%) in BA and 317 (72.4%) in LA. Out of these, 343 events (78%) were solved chairside: 191 (43.6%) were replacements of retention caps, 113 (25.8%) were minor acrylic repairs, 26 (5.9%) pressure ulcers had to be relieved, and 13 (3%) were related to abutments. LA required 179 insert replacements compared to 12 in the BA group. The overall initial treatment cost was EUR 3850 (base year of the analysis: 2003). The average total maintenance cost in relation to the initial cost for the LA and BA groups was 19.11 (range 0–82.24%) and 18.91% (range 0–113.26%) respectively (p = 0.540). Conclusions: The seven-year maintenance costs for a 2IOD is acceptable when the patient is regularly checked and professionally maintained. Most events are easily solvable chairside, but a few patients required more expensive interventions, regardless of the type of attachment used.

Lateral Alveolar Ridge Augmentation with an Autogenous Bone Block Graft Alone with or without Barrier Membrane Coverage: a Systematic Review and Meta-Analysis

Objectives

To test the hypothesis of no difference in implant treatment outcome following lateral alveolar ridge augmentation with autogenous bone block graft with or without barrier membrane coverage.

Material and Methods

PubMed (MEDLINE), Embase and Cochrane library search in combination with a hand-search of relevant journals was conducted. Human studies published in English until the 8^th of February 2021 were included. Randomised controlled trials with an observation period longer than three months were included. Survival of implants and suprastructures were considered as primary outcomes measures, whereas peri-implant marginal bone loss, dimensional changes of the alveolar ridge, bone regeneration, patient-reported outcome measures, biological and mechanical complications were secondary outcome measures, as evaluated by descriptive statistics and meta-analysis including 95% confidence interval (CI).

Results

Electronic search and hand-searching resulted in 411 entries. Five randomised controlled trials characterised by low or high risk of bias fulfilled inclusion criteria. No statistically significant difference between the two treatment modalities was observed in any of the outcome measures. However, barrier membrane coverage was associated with a non-significant gain in alveolar ridge width of 0.5 mm (95% CI = -0.1 to 1.1) and diminished resorption of -0.9 mm (95% CI = -2.4 to 0.7) compared with no barrier membrane coverage.

Conclusions

Comparable implant treatment outcomes were revealed following lateral alveolar ridge augmentation with autogenous bone block graft alone with or without barrier membrane coverage. However, postoperative dimensional changes of the augmented seems to be diminished with the use of barrier membrane coverage as evaluated by two-dimensional linear measurements.

Impact of rehabilitation versus edentulism on systemic health and quality of life in patients affected by periodontitis: A systematic review and meta-analysis

AIM

To investigate the effect of rehabilitation in fully/partially edentulous patients with stage IV periodontitis on oral-health-related quality of life (OHRQoL) and systemic health.

MATERIALS AND METHODS

A systematic electronic and manual search was conducted. Three authors independently reviewed, selected, and extracted the data. Outcomes were OHRQoL (Oral Health Impact Profile 14 [OHIP-14] and OHIP-49, General Oral Health Assessment Index [GOHAI], visual analogue scale, symptoms registration) and systemic health-related outcomes (incidence and prevalence of systemic diseases, values of systemic disease indicators). Qualitative data were synthesized for OHRQoL and systemic health-related outcomes. Meta-analysis was conducted on available quantitative data.

RESULTS

The search identified 59 articles (6724 subjects in total). OHRQoL improved across all the studies, irrespective of the number of missing teeth, their location, or treatment modality. Meta-analysis showed significant improvement of OHIP-49 (36.86, p < .01) in manuscripts including subjects affected by periodontitis, consistently with the remaining literature (reduction of score points post rehabilitation: OHIP-14 = 10.52, OHIP-49 = 56.02, GOHAI = 5.40, p < .01 for all). Non-rehabilitated subjects exhibited inferior cognitive status, higher medication intake, and frailty. However, our data are limited and should be interpreted with caution.

CONCLUSIONS

Oral rehabilitation improves OHRQoL and, potentially, systemic health in edentulous patients. It is unclear whether these findings may be extrapolated to patients with stage IV periodontitis.

Prosthetic aftercare, mastication, and quality of life in mandibular overdenture wearers with narrow implants: A 3-year cohort study

OBJECTIVES

This cohort study investigated clinical, functional, and quality of life outcomes, along with prosthetic maintenance events in mandibular overdenture (MO) wearers for 3 years.

METHODS

Thirty MO wearers with narrow diameter implants (NDIs) and locking taper stud abutments (Facility-Equator system) were annually monitored by registering the visible plaque index (VPI), peri‑implant inflammation (PI), calculus presence (CP), probing depth (PD), bleeding on probing (BOP), secondary implant stability (ISQ), marginal bone loss (MBL), masticatory performance and dental impact in daily life (DIDL) questionnaire domains. Multilevel mixed-effects linear regression was performed to analyse changes over time. Chi-square tests were performed to analyse the relationship between the appearance of prosthetic complications and maintenance occurrences. The survival rate of patients with NDIs was calculated using the Kaplan-Meier test.

RESULTS

Twenty-six individuals attended all follow-ups, the survival rate of 83.3% in the first year was maintained, and no one implant was lost over the 3-year period. There were significant differences for PD between 1 and 3 years (p ≤ 0.01) and between 2 and 3 years for PI (p ≤ 0.01), GI (p ≤ 0.01), ISQ (p = 0.02), and MBL (p ≤ 0.01). All masticatory performance outcomes showed significant differences (p ≤.01). Prosthetic maintenance events decreased significantly over time. Appearance, general performance, and eating and chewing domains presented high effect sizes.

CONCLUSION

Continued changes were observed in the clinical parameters of MO users over the 3-year period. In addition, most functional parameters, except for particle homogenization, improved significantly over time. The positive impact on quality of life is likely related to the significant reduction in prosthetic maintenance events.

CLINICAL SIGNIFICANCE

Periodic returns to assess peri‑implant tissues and MO maintenance should be performed to ensure the success of rehabilitation to assure improvements in masticatory function and oral health-related quality of life.

What is the evidence on the added value of implant-supported overdentures? A review

Background

Implant‐supported overdentures (IODs) have been reported to increase patients' oral health‐related quality of life (OHRQoL) in comparison with conventional dentures (CDs); however, the conclusiveness of evidence on the clinical effectiveness and value for money of IODs versus CDs remains unclear.

Purpose

To review how the added value of IODs is demonstrated in the literature.

Materials and methods

MEDLINE, EMBASE, and the Cochrane Database were searched for randomized control trials, controlled clinical trials, and prospective cohort studies containing evaluations of the economic and health benefits and costs of IODs. Information about the clinical effectiveness, such as magnitude of bite forces or chewing efficacy, OHRQoL, costs, and cost‐effectiveness of IODs, was extracted.

Results

A total of 17 articles were included, reporting 15 economic evaluations: 11 cost‐utility analyses (CUAs), 2 of which were combined with a cost‐effectiveness analysis (CEA), and 2 cost–benefit analyses (CBAs). Seven CUAs used the Oral Health Impact Profile (OHIP) questionnaire while four used satisfaction questionnaires to assess the OHRQoL. One study applied quality‐adjusted prosthesis years (QAPYs) for this purpose. The CBAs expressed both the beneficial outcome and the costs of the IOD in monetary terms. The included studies employed a large variety of economic evaluation methods, which limited cross‐study comparability.

Conclusions

On the basis of existing economic evaluations, IODs have frequently been suggested to be a cost‐efficient treatment alternative to CDs; however, the comparability between the various economic evaluation studies was limited due to the different outcome measures used. In addition, it remains unclear whether the additional health benefits of IODs outweigh the higher costs. This is largely dependent on the decision maker's valuation of oral health outcomes. Future research is encouraged to further elucidate patient willingness to pay for IODs and the societal return on investing in IODs more generally.

Mandibular residual ridge morphology in relation to complete dentures and implant overdentures-Part II: Predictors for effectiveness of implant overdenture therapy

BACKGROUND

The significance of mandibular residual ridge height and satisfaction with conventional complete dentures (CCD) as predictors for the added value of implant-overdenture (IOD) therapy is unknown.

PURPOSE

To investigate the predictive value of thresholds for (1) residual ridge height at premolar location (PRH), and (2) satisfaction with CCD-stability for the added value of two intraforaminal implants supporting the mandibular CCD.

METHODS

Thirty CCD wearing patients (67.9 ± 7.0 years) for whom a new CCD was advised, received a new CCD. Mandibular gypsum models were digitally measured. After 3 months free of complaints (T1), perceived CCD-stability was evaluated, and participants received two intraforaminal implants. At T1 and T2 (3 months free of complaints after IOD therapy) participants completed OHIP14-CN, and denture satisfaction (VAS) questionnaires, and performed mixing ability tests. Participants were grouped according to PRH of ≥6.15 mm versus < 6.15 mm, and perceived CCD-stability satisfied vs. dissatisfied. Scores at T2 were compared to T1 (paired t-tests). Predictive values of PRH and CCD-stability were analyzed with logistic multivariate regression models.

RESULTS

At T2, only participants with PRH of <6.15 mm or dissatisfied with CCD-stability had significant lower OHIP-total and domain scores for 'physical pain' and 'physical disability' and significantly higher VAS scores for perceived chewing function, denture retention and oral comfort. Regression analyses showed that participants with PRH of <6.15 mm, or dissatisfied with CCD-stability had significantly higher chance for lower OHIP-total and domain scores 'physical pain' and 'physical disability', and for higher VAS scores for perceived chewing function, denture retention and oral comfort at T2. Masticatory performance improved significantly after IOD therapy, but independent of PRH and CCD-stability.

CONCLUSION

PRH and satisfaction with CCD-stability were adequate prognostic indicators for improvement of oral health-related quality of life and denture satisfaction by mandibular IOD therapy.

Crestal Bone Changes and Patient Satisfaction with Single Implant-Retained Mandibular Overdentures with Dalla Bona and Locator Attachments with Immediate Loading Protocols. A Randomized Controlled Clinical Study

PURPOSE

There is no enough evidence present on the success of single implant-retained mandibular overdentures (SIMO) with Dalla Bona and Locator attachments. This study aims to compare crestal bone loss and patient satisfaction with SIMO with Dalla Bona and Locator attachment following immediate loading protocols.

MATERIAL AND METHODS

Twelve patients included in Group 1 received immediate SIMO with Dalla Bona attachments, and another twelve patients in Group 2 received immediate SIMO with Locator attachments in the mid symphyseal region. The follow-up was scheduled at 6 and 12 months after implant placement. The patient satisfaction with the denture was evaluated with the visual analog scale (VAS) score. The data obtained were statistically analyzed with the independent student t-test for intergroup comparison and repeated measures of ANOVA followed by Bonferroni's Post hoc analysis for intragroup comparison of mean crestal bone loss at a different time interval.

RESULTS

Ten patients each in both the groups were available for follow-up. Crestal bone loss at 6 months follow-up for Dalla Bona group was 0.42 ± 0.10 mm on the mesial side and 0.43 ± 0.14 mm on the distal side and at 1 year 1.54 ± 0.16 mm on the mesial side and 1.66 ± 0.13 mm on the distal side. The mean crestal bone loss at 6 months follow-up for Locator group was 0.48 ± 0.16 mm on the mesial side and 0.45 ± 0.11 mm on the distal side and at 1 year was 1.71 ± 0.22 mm on mesial side and 1.74 ± 0.28 mm on the distal side. There was difference in bone loss at 6 months (mesial: 0.06 mm, p = 0.327; distal:0.02 mm; p = 0.726) and at 1 year (mesial: 0.17 mm, p = 0.063; distal: 0.08 mm; p = 0.423) in between two groups but the difference was statistically insignificant. There was a significant difference found in the VAS score for patient satisfaction with SIMO with Dalla Bona attachments and Locator attachments at 6 months (54.2 vs. 51.8, p = 0.005) and 1 year (60.6 vs. 55.2, p = 0.005).

CONCLUSIONS

Patient satisfaction with SIMO with Dalla Bona attachments was higher during the follow-up. SIMO with Dalla Bona attachments had less crestal bone loss and less prosthetic complications when compared to Locator attachments, although the difference in the bone loss was statistically insignificant.

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

OBJECTIVES

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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