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

Immediate loading of dental implants in edentulous mandibles using Locator attachments or Dolder bars: A 9-year prospective randomized clinical study

AIM

To evaluate the long-term survival, incidence of prosthetic/technical and biological complications and the oral-health-related quality of life in patients with an edentulous mandible who were fitted with overdentures on two immediately loaded implants in the symphyseal area.

MATERIALS AND METHODS

Forty-six patients with edentulous mandibles received two immediately loaded implant-retained dentures with either two Locator attachments or egg-shaped bar attachments. Implant outcomes were recorded after a period of observation of 9 years and included prosthetic complications, modified gingiva index (mGI), modified plaque index (mPI), oral health impact profile (OHIP-G) and radiographic estimation of bone loss.

RESULTS

In 2020/2021, 27 patients with 54 implants were still available for follow-up. In total, nine implants in six patients were lost. Survival was 89.1% in the bar group and 91.3% in the Locator group. Implant success was 84.6% in the Locator group and 76.9% in the bar group. The mPI values were significantly higher in the bar group than in the Locator group, whereas no difference was seen in the mGI values. During the observation period, 152 prosthetic complications occurred, but the OHIP-G score did not differ significantly.

CONCLUSIONS

There was no difference in implant survival between Locator or joint bar attachments over a 9-year observation period. Joint bar attachments were associated with slightly more complications, while patients in the Locator group were able to maintain better oral hygiene. The study was registered in the German Register of Clinical (Trials DRKS00004245).

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.

Prosthetic complications and quality of life among wearers of mandibular overdenture with the Facility-Equator system

This longitudinal study aimed to assess the performance of the Facility-Equator system as mandibular overdenture (MO) retainers from a prosthetic perspective during 2 years of loading and to investigate the oral health-related quality of life (OHRQoL) and whether prosthetic events can affect the OHRQoL. Twenty-four patients (68.1 ± 7.51 years) reported their OHRQoL through the Geriatric Oral Health Assessment Index (GOHAI) and Oral Health Impact Profile (OHIP-EDENT) questionnaires before MO loading and after 1 and 2 years of usage. Prosthetic occurrences were recorded during this period. Data were analyzed using the Wilcoxon test, Mann-Whitney test, and Spearman correlation coefficients. Of the 127 prosthetic events that occurred in the first year, the most frequent events were prosthesis adjustments (16.5%), dislodgement of the Equator attachment (14.17%), and O-ring replacement (11.8%). Eighty-seven prosthetic events were recorded in the second year, the most frequent events being prosthesis adjustments (27.6%), O-ring replacement (20.7%), and recapturing the female matrix (11.5%). All domains of the GOHAI and OHIP-EDENT questionnaires exhibited a significant difference (p < 0.05) between the baseline and 1- and 2-year evaluations, except in the Social Disability and Psychological Discomfort domains (p > 0.05) of OHIP-EDENT after 1 year. Complications related to prosthetic maintenance, such as fracturing of the prosthesis, Equator dislodgement, prosthesis rebasing, and new overdenture confection, affect the OHRQoL (p < 0.05), primarily the Physical Pain and Discomfort domains, especially in the first year of MO loading.

Circumferential bone level and bone remodeling in the posterior mandible of edentulous mandibular overdenture wearers: influence of mandibular bone atrophy in a 3-year cohort study

OBJECTIVES

Evaluate circumferential bone level and morphological alterations in the posterior mandibular ridge of atrophic (AP) and non-atrophic (NAP) patients using implant-retained mandibular overdentures (MO) over 3 years.

MATERIALS AND METHODS

Twenty-six edentulous patients categorized according to mandibular atrophy (AP = 13/NAP = 13) received two narrow diameter implants (Facility, 2.9 × 10 mm) in the anterior region of mandible. The vertical and horizontal bone level was measured along with bone remodeling at 4 distances from the mental foramen in the posterior region of the mandible (L1-L4) via CBCT.

RESULTS

NAP showed significantly higher total height and medullary height in all posterior regions at 1 and 3 years (p ≤ 0.01). Cortical height and width were significantly higher (p ≤ 0.05) in this group at distances L1 and L4, respectively, in year 1. NAP shows a significantly higher % of medullary height at distances L1 (p ≤ 0.05), L2 (p ≤ 0.01), and L3 (p ≤ 0.05) after 1 year, and at all distances (p ≤ 0.05) after 3 years. Bone remodeling in the groups differed significantly (p ≤ 0.05) in terms of cortical width and % medullary width at L3.

CONCLUSION

AP and NAP showed similar vertical and horizontal bone level. Bone resorption in the posterior ridge was stabilized by MO over 3 years; however, AP are more susceptible to the long-term substitution of medullary bone by cortical bone.

CLINICAL RELEVANCE

This study is the first to longitudinally evaluate bone dimensions in atrophic and non-atrophic two-implant MO users by CBCT and revealed that MO is a predictable treatment based on the stabilization of the posterior bone resorption.