Clinical outcomes and bone-level alterations around one-piece mini dental implants retaining mandibular overdentures: 5-year follow-up of a prospective cohort study

One-Piece Mini Dental Implant-Retained Mandibular Overdentures: 10-Year Clinical and Radiological Outcomes of a Non-Comparative Longitudinal Observational Study

This study presents the first 10-year follow-up investigation of the implant survival and peri-implant outcomes of one-piece mini dental implants (MDIs) retaining mandibular implant overdentures (IODs), including marginal bone level alterations (ΔMBLs), clinical peri-implant parameters, and complications. Twenty participants with horizontally atrophied mandibles received complete dentures and four MDIs (diameter 1.8 mm) at baseline. The dentures were converted into IODs with O-ring attachments. The 10-year follow-up comprised a radiological assessment of ΔMBLs, peri-implant parameters, as well as biological and technical complications. Results from a 10-year follow-up of 14 participants showed a 100% implant survival rate for all 56 implants. The mean ΔMBL after 10 years was -1.12 ± 0.80 mm, with 49 implants classified as successful (ΔMBL < 2 mm) and 7 implants with satisfactory survival (ΔMBL 2-4 mm). Time after implant placement significantly influenced ΔMBL, with stable MBLs after 5 years. The prosthetic survival rate after 10 years was 93%. ΔMBLs were not influenced by implant position or gender but were significantly smaller in subjects older than 65 years. Conclusively, one-piece MDIs with O-ring attachments offer a reliable treatment option for horizontally atrophied mandibles after 10 years, with high implant and prosthetic survival rates, potentially benefiting from advanced age regarding peri-implant bone stability.

Clinical Outcomes of Three versus Four Mini-Implants Retaining Mandibular Overdenture: A 5-Year Randomized Clinical Trial

Background and Objectives: Due to a lack of long-term clinical studies that would clarify whether the insertion of three mini-implants (MDIs) can be as successful treatment as the insertion of four MDIs for the retention of mandibular overdentures (ODs), this 5-year prospective cohort study was set up. Materials and Methods: Participants (n = 83) randomly received either four or three MDIs and a mandibular OD. Clinical examinations were performed at the baseline, as well as after one, three, and five years, respectively. A total of 73 participants (38 in the four-MDI and 35 in the three-MDI groups) partook in the study. The marginal bone level change, success and survival rates, and prosthodontic maintenance were assessed. Results: Repeated measures showed that the mean peri-implant bone loss increased progressively at a small amount over five years in both groups (four-MDI group = -0.36 ± 0.74; three-MDI group = -0.33 ± 0.27 mm; p < 0.05). However, an ANCOVA revealed no significant effects of the group (no significant difference between the three- and the four-MDI groups; F = 0.085; p = 0.771), gender (F = 0.023; p = 0.88), or covariate age (F = 1.95; p = 0.167) on the dependent variable: the 5-year MBL change. The success rate (together with successful survival) was 93.8% in the four-MDI group and 91.7% in the three-MDI group. The log-rank (Mantel-Cox) test revealed no significant differences between them (X2 = 0.373; p = 0.541). Conclusions: In patients with narrow ridges, the insertion of three MDIs in the mandible for overdenture retention can be equally as successful as the insertion of four MDIs.

Mini-implant mandibular overdentures under a two-step immediate loading protocol: A 4-6-year retrospective study

OBJECTIVES

This retrospective study to evaluate the treatment outcomes of mandibular mini-implant overdentures (MIODs) placed under a two-step immediate loading protocol.

BACKGROUND

The mini-implant overdenture emphasises the advantages of simplicity using flapless surgery and immediate loading. However, some mini-implant have lowe initial stability.

MATERIALS AND METHODS

A total of 30 participants who used mandibular MIODs and maxillary removable complete dentures (RCDs) over 4 years were included. Four one-piece mini-implants (<3 mm in diameter) were placed by a flapless surgical approach after fabrication of new RCDs, and the O-ring attachment was attached at least 8 weeks after implant placement.

RESULTS

The average observation period was 58.9 ± 9.2 months after mini-implant loading. The survival rate of the implants was 100.0%, and the overall change in mean marginal bone level (ΔMBL) was -0.9 ± 1.1 mm. The implant success rate was 83.3% at the implant level, and 66.7% at the patient level. The mean initial Periotest value was 0.9 ± 3.1, and it was positively associated with ΔMBL and implant success (P < .05). Patient satisfaction improved after conversion from RCDs to MIODs (P < .05), and mastication and pain showed greater satisfaction with longer loading time (P < .05).

CONCLUSIONS

The mandibular MIODs could be chosen as an alternative treatment under a two-step immediate-loading protocol in edentulous patients with limited alveolar bone volume. To ensure superior treatment outcomes of MIODs, initial stability of implant must be obtained using as wide a diameter as possible within the anatomically allowable limits.

Factors and clinical outcomes for standard and mini-implants retaining mandibular overdentures: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Standard-diameter dental implants are not always applicable because of anatomic limitations of the residual ridge. Thus, mini-implants have been increasingly used and offer an alternative. However, data regarding prosthetic complications, maintenance factors, and clinical outcomes are limited.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare prosthetic complications and maintenance events and clinical outcomes in residual ridges rehabilitated with mandibular implant overdentures (IODs) by using standard implants or mini-implants.

MATERIAL AND METHODS

Nine electronic databases were searched. Quantitative analyses to measure the risk ratio (RR) and standardized mean difference (SMD) were applied. Those methods were used to assess prosthetic complications and maintenance events (abutment adjustments, replacement of retentive element, occlusal adjustment, and overdenture fracture) and clinical outcomes related to postoperative pain, probing depth (PD), plaque index (PI), marginal bone loss (MBL), and implant survival rate.

RESULTS

Altogether, 7 publications were selected. Mini-implants presented reduced abutment adjustments (RR 0.23 [0.07, 0.73], P=.01), replacement of retentive element (RR 0.41 [0.31, 0.54], P<.001), occlusal adjustment (RR 0.53 [0.31, 0.91], P=.02), and overdenture fracture (RR 0.46 [0.23, 0.94], P=.03) compared with standard implants. Additionally, mini-implants presented lower values for PI at 6 months (SMD -0.27 [-0.47, -0.08], P=.006) and 12 months (SMD -0.25 [-0.46, -0.05], P=.01). No additional tangible differences were noted.

CONCLUSIONS

Mini-implants might be an alternative choice based on the number of prosthetic complications and maintenance events. This was also confirmed by the comparable clinical data between standard implants and mini-implants.

Narrow-diameter versus regular-diameter dental implants for mandibular overdentures: A systematic review and meta-analysis

PURPOSE

The aim of this systematic review was to compare treatment outcomes in terms of implant survival rate, marginal bone loss, and patient-reported outcome measures (PROMs) between narrow-diameter implants and regular-diameter implants (RDIs) for mandibular implant overdentures (MIOs).

METHODS

This study was based on the methodology adapted as per Cochrane. Medline, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus were searched for pertinent studies published by July 22, 2022. Outcome parameters included in this meta-analysis were implant survival rate, marginal bone loss, visual analogue scale score for patient satisfaction, and value of oral health impact profile.

RESULTS

A total of 782 non-duplicate articles and 83 clinical study registrations were identified from database and hand searches, of which 26 were eligible for full-text searches. Finally, 12 publications reporting on 8 independent studies were included in this review. In the meta-analysis, implant survival rate and marginal bone loss did not significantly differ between narrow-diameter implants and RDIs. Regarding RDIs, narrow-diameter implants were associated with significantly better outcomes in general patient satisfaction and oral health-related quality of life than RDIs for mandibular overdentures.

CONCLUSIONS

Narrow-diameter implants have competitive treatment outcomes compared to RDIs in terms of implant survival rate, marginal bone loss, and PROMs. [Correction added on July 21, 2023, after first online publication: The abbreviation RDIs was changed to PROMs in the preceding sentence.] Thus, narrow-diameter implants might be an alternative treatment option for MIOs in situations with limited alveolar bone volume.

Implant survival/success and peri-implant outcomes of titanium-zirconium mini implants for mandibular overdentures: Results from a 1-year randomized clinical trial

OBJECTIVE

To report the 1-year implant survival/success and peri-implant outcomes of mandibular overdentures retained by four titanium-zirconium mini implants (Straumann® Mini Implant System), and to assess how surgery and loading protocols influence these outcomes.

MATERIALS AND METHODS

A 2 × 2 factorial randomized clinical trial (RCT) tested the combined effects of two loading protocols (immediate or delayed) and two surgical approaches (flapless or flapped) on the success/survival of the mini implants, and peri-implant parameters (plaque, bleeding, sulcus depth, gingival position, and marginal bone loss). Outcomes were assessed up to 1-year after loading, and generalized estimating equations (GEEs) were used to analyze longitudinal and within-patient clustered data.

RESULTS

Two hundred and ninety-six implants were placed in 74 patients. The implant survival/success rates after 1 year were 100%, and no major biological complications were observed. After 1-year, descriptive data suggest no noticeable changes in plaque scores, whilst a reduction in bleeding scores at the 6-month and 1-year follow-ups compared to baseline. Good longitudinal stability was observed for the probing depth and gingival margin height measures. Overall mean marginal bone loss was 0.68 (±0.68) mm after 3 months and 0.89 (±0.75) mm after 1-year. The flapless protocol showed better results on soft tissue stability and health but a slightly higher risk for marginal bone loss.

CONCLUSION

The results of this RCT suggest that mandibular overdentures retained by this novel mini implant system represent a safe and predictable treatment option as confirmed by implant survival/success and peri-implant outcomes, even when flapless surgery and immediate loading protocols are adopted.

Mini-Implants Retaining Removable Partial Dentures in Subjects without Posterior Teeth: A 5-Year Prospective Study Comparing the Maxilla and the Mandible

Background and objectives: Long-term studies of clinical outcomes of mini-implants (MDIs) in the first premolar/canine sites retaining a bilateral free-ending removable partial dentures (RPD) in Kennedy class I subjects have not been well documented. The aim was to assess clinical outcomes in a prospective 5-year cohort study comparing the mandible and maxilla. Material and Methods: Participants (n = 92) who received two MDIs each and a new RPD were reviewed after one, three and five years. A total of 71 participants (82 mini-implants in the mandible; 58 in the maxilla) completed the study. Marginal bone level change, success, survival rates, Modified Plaque (MPI) and Bleeding Indices (MBI) were assessed. Results: The five-year success rate was 93.3% and 93.4% (p > 0.05), in the mandible and the maxilla, respectively. Mean peri-implant bone loss (MBL) increased significantly over five years (p < 0.01) to 0.50 mm in the mandible and 0.52 mm in the maxilla. Age had a significant effect on the MBL (higher rates in younger participants), while jaw of insertion, gender, and antagonistic jaw status did not. MPI and MBI were not significantly correlated with MBL. Conclusions: The insertion of two MDIs in previous first premolar/canine sites for retention of a free-end saddle RPD can be a successful treatment modality in subjects with narrow alveolar ridges.

The Effect of Mini Dental Implant Number on Mandibular Overdenture Retention and Attachment Wear

Purpose

Evaluate the effect of different mini-implant numbers on overdenture retention and evaluate attachment wear following one year of simulated placement/removal. Material and Methods. Nine models simulating atrophic mandibles held 27 mini dental implants in three groups of 2, 3, and 4 mini-implants. A total of 1080 simulated placement/removal cycles were carried out, and a digital force gauge was used to measure the overdenture dislodgment force. The means of the retention forces were analyzed using SPSS with one-way ANOVA and post hoc (p < 0.05). The inner diameter of attachment inserts was evaluated using a light microscope before and after testing. A paired t-test was used to compare the mean of inner ring diameters (p < 0.05).

Results

The retention was significantly reduced regardless of the mini dental implant number, but the number affected overdenture retention. The placement of 4 mini dental implants provided higher retention and less reduction in retentiveness. However, no significant difference was found when 3 mini dental implants were compared to 2 mini dental implants (p = 0.21). Microscopic examination showed abrasion wear in all inserts following testing. However, the inserts of the 4 mini dental implants showed less wear than those used for 2 or 3 mini dental implants with p ≤ 0.001 and p ≤ 0.001, respectively.

Conclusion

Mini dental implant overdenture retention force and attachment wear could improve by increasing the mini dental implants to 4. However, there was no difference in retention force or attachment wear when 2 or 3 mini dental implant overdentures were compared.

Periodontitis and peri-implantitis in elderly people experiencing institutional and hospital confinement

An increasing number of elderly people retain their natural teeth into old age and further, the prevalence of endosseous implants for supporting oral prosthesis is ever increasing. These teeth and implants now present a considerable challenge in terms of maintenance, especially when patients become dependent on care. Periodontal and peri-implant diseases are more prevalent in elderly than in younger age cohorts. There are distinct differences related to the inflammatory response between periodontal and peri-implant tissues, both in young and old age. The age-related reasons for the increase in periodontal infections may be related to poor oral hygiene because of a loss of dexterity or vision, but also to immunosenescence. This term describes the aging of the immune system and the decline of its effectiveness with age. Low-grade infections, like chronic periodontitis, may cause low-grade inflammation and subsequently increase the likelihood of developing chronic diseases. In return, treatment of periodontitis may improve general health, as demonstrated for diabetes. A second mechanism illustrating how poor oral health translates into systemic disease is the risk of developing aspiration pneumonia. The treatment options in old age should be evaluated with regard to the issues of general health and maintenance. Systematic periodontal maintenance therapy, as performed in younger age cohorts, may be difficult to implement in elderly people experiencing institutional or hospital confinement because of logistics, barriers related to patients and caregivers, or cost. The scale of periodontal disease in old age represents a public health issue.

Clinical outcomes of different implant types in mandibular bar-retained overdentures: a retrospective analysis with up to 20 years follow-up

PURPOSE

To determine the clinical and radiological outcomes of hybrid-design- (HD) and bone-level (BL) implants for bar-retained mandibular implant-overdentures (IODs).

METHODS

For this retrospective study, edentulous patients who had received maxillary complete dentures and mandibular bar-retained IODs were invited for a follow-up assessment. Implant survival, implant success and health of peri-implant tissues were assessed on an implant level-based analysis. Patient-based parameters served to identify risk factors for peri-implant bone loss, presence of peri-implantitis and success.

RESULTS

Eighty patients (median age 72.72 [67.03; 78.81] years, 46 females) with 180 implants (median follow-up 12.01 [10.82; 21.04] years) were assessed. There was no difference concerning the rate of implant failure (p = 0.26), or peri-implantitis (p = 0.97) between HD and BL implants. Solely in one study group, there was the presence of peri-implant pus. Implant success was higher in BL implants with one group being notably higher than the comparing groups (p = 0.045). For bone loss, a width of keratinized mucosa (KM) ≤ 1 mm (p = 0.0006) and the presence of xerostomia (p = 0.09) were identified as risk factors. Smoking (p = 0.013) and a higher body mass index (BMI) (p = 0.03) were a risk factor for peri-implantitis. As risk factors for reduced implant success, a small width of KM (p = 0.003) and the presence of xerostomia (p = 0.007) were identified.

CONCLUSIONS

For mandibular bar-retained IODs, both BL and HD implants are mostly successful. A minimum of 1 mm KM around implants and normal salivary flow are relevant factors for implant success and stable peri-implant bone levels. Smoking and a high BMI are potential risk factors for peri-implantitis.

Flapped versus flapless surgery and delayed versus immediate loading for a four mini implant mandibular overdenture: a RCT on post-surgical symptoms and short-term clinical outcomes

OBJECTIVE

This factorial randomized clinical trial tested the effects of the surgical approach (flapped - FPS versus flapless - FLS surgery) and loading protocol (delayed - DL versus immediate - IL) for treatment with a four mini implant mandibular overdenture.

MATERIAL AND METHODS

A total of 296 one-piece titanium-zirconium mini implants were inserted in 74 patients (IL/FLS=17; IL/FPS=18; DL/FLS=20; DL/FPS=19). Outcomes included patient's perceived surgical burdens, clinical time, implant survival, and post-surgical symptoms and complications, assessed immediately after surgery, in the 7-day and 6-week follow-ups.

RESULTS

Perceived surgical burdens were relatively low, higher for females, and no difference was found between flapped and flapless surgery. Surgical time was lower for flapless surgery. Overall symptoms were mild after 24 hours, and higher for females. Less symptoms were recorded for the flapless surgery compared to the flapped for the delayed loading patients, and flapless surgery was associated with lower risk of bleeding. No early implant failure was observed until the 6-week follow-up. Delayed was associated with discontinuous use of the prosthesis and poor function. Lower complaint rates were observed for immediate loading regardless of the surgery protocol.

CONCLUSIONS

Mini implants for mandibular overdenture is a feasible option regardless of surgical access and loading protocol, with high safety and predictable survival rates, and low incidence of post-insertion complications. Flapless surgery requires less clinical time and result in easier intraoral prosthetic incorporation of attachments compared to flapped surgeries. Immediate loading did not increase the risk of early implant failure when satisfactory primary stability was achieved.

Comparative clinical study of conventional dental implant and mini dental implant-retained mandibular overdenture: A 5- to 8-Year prospective clinical outcomes in a previous randomized clinical trial

AIM

To compare the long-term prospective clinical outcomes in a previous randomized controlled clinical trial (RCT) of 2 Mini Dental Implant (2MDI), 4 Mini Dental Implant (4MDI), and 2 Conventional Dental Implant (2CDI)-retained mandibular overdenture with follow-up between 5 to 8 years.

MATERIALS AND METHODS

Thirty-seven patients formerly participated in the Comparative Clinical Study of CDI and MDI for Mandibular Overdenture were requested for examination of clinical outcomes. A total of 104 implants were placed with mean follow-up periods 6.64 ± 0.60 years. In Group 1 (2MDI) and Group 2 (4MDI), implants were placed and immediately loaded with Equator® attachments to retained mandibular overdenture. In Group 3 (2CDI), implants were placed and delayed 3 months for denture loading with ball attachment. The success rate, survival rate, clinical implant performance scale (CIP scale), peri-implant tissue status, prosthetic complication, implant stability quotient (ISQ), marginal bone level change (MBLC), and patient satisfactions were analyzed.

RESULTS

After 5 to 8 years follow-up, the success rate in Groups 1, 2, and 3 were 90.91%, 93.33%, and 54.55%, respectively. The success rate in Group 3 was significantly lesser than Group 1 (p = 0.016) and Group 2 (p < 0.001). The survival rate in Groups 1, 2, and 3 was 100%, 96.67%, and 90.91%, respectively, and showed no significant differences. Mean ISQ reported no significant differences between groups. Mean MBLC were 0.57 ± 1.19 mm, 0.68 ± 0.90 mm, and 1.55 ± 1.60 mm in Groups 1, 2, and 3, respectively. Group 3 reported significantly greater mean MBLC than Group 1 (p = 0.016) and Group 2 (p = 0.011), but Groups 1 and 2 were not significantly differences. The overall patient satisfactions were reported as not significant differences between groups.

CONCLUDE

Two MDI-retained mandibular overdentures with immediate loaded protocol performed had favorable clinical outcomes, cost effectiveness, and overall patient satisfactions after 5 to 8 years follow-up.

Oral diadochokinesis and associated oro-facial function in young and old German mother-tongue speakers: A cross-sectional study

Objectives

The aims of this study were to compare oral diadochokinesis and to test associations with oro‐facial functional parameters in healthy young and old German speakers.

Background

Oral diadochokinesis is a key component in the concept of oro‐facial hypofunction and relates to tongue and lip motor function but may depend on the linguistic background.

Materials and methods

Healthy German speakers with a minimum of 20 teeth were recruited to form a young (<60 years) and an older group (≥60 years). Oral diadochokinesis was assessed as the number of repetitions/s for the monosyllables /pa/, /ta/ and /ka/ to evaluate movement capacity of the lip, the anterior region of the tongue and the posterior region of the tongue, respectively. Maximum voluntary lip force, maximum voluntary bite force, masticatory performance, maximum voluntary tongue pressure, xerostomia and swallowing function were assessed with validated instruments. Results are presented as median (IQR).

Results

Sixty participants formed the younger group (n = 35, 30.0 years [24.0‐49.0]) and the older group (n = 25, 64.0 years [62.0‐72.0]). Counts/s of /ta/ were different between age groups (younger group: 6.0 vs older group: 5.4) but not for syllables /pa/ (younger group: 6.0 vs older group: 5.8) and /ka/ (younger group: 5.6 vs older group: 5.0). The oral diadochokinesis with /pa/ was overall associated with maximum voluntary lip force; oral diadochokinesis performed with /ta/ was associated with tongue pressure, and oral diadochokinesis with /ka/ with swallowing function. Masticatory performance was not associated with oral diadochokinesis but with maximum voluntary bite force, xerostomia and with maximum voluntary tongue pressure.

Conclusions

The published thresholds for oral diadochokinesis should be reconsidered in non‐Japanese mother‐tongue speakers. However, they still play an important role in the overall concept of oro‐facial functional assessment.

Influence of the loading protocol and platform switching in two-implant bar-retained overdentures: 3-year results from a randomized controlled equivalence clinical trial

OBJECTIVES

To test the null hypothesis that vertical peri-implant bone level alterations (ΔIBL) are equivalent in immediately (IL) and 3-month post-placement (DL) loaded implants in mandibular implant overdentures (IODs) on two implants.

MATERIALS AND METHODS

Thirty-two patients receiving two interforaminal implants, one with a platform-switched and one with a platform-matching abutment were randomly assigned to the IL or DL group (allocation ratio 1:1). All implants were primarily splinted with chairside-customized bars, converting the existing removable complete dentures to IODs. Standardized radiographs were recorded. The influence of the loading protocol (IL vs. DL), implant platform (platform switched vs. platform matching), implant site (43 vs. 33), participant age (≤65 vs. >65 years), and definition of baseline (implant placement vs. implant loading) were analyzed, applying linear regression analyses (α = 0.05). The equivalence range was [-0.4; 0.4].

RESULTS

Three participants of the IL group were lost during follow-up. The overall mean ΔIBL was -0.96 ± 0.89 mm. The ΔIBL was equivalent in terms of the implant platform and implant site but not in terms of participant age (in favor of more elderly participants) and the loading protocol. A significantly smaller ΔIBL was observed in the IL when the baseline was considered to be implant placement (p = .017), but not when it was considered to be implant loading (p = .084).

CONCLUSION

Immediate loading of primary-splinted implants in two-implant bar-retained overdentures, seems beneficial relative to loading 3 months post-placement, with respect to ΔIBL. The ΔIBL were equivalent in terms of platform switching.

Consensus on the terminologies and methodologies for masticatory assessment

A large number of methodological procedures and experimental conditions are reported to describe the masticatory process. However, similar terms are sometimes employed to describe different methodologies. Standardisation of terms is essential to allow comparisons among different studies. This article was aimed to provide a consensus concerning the terms, definitions and technical methods generally reported when evaluating masticatory function objectively and subjectively. The consensus is based on the results from discussions and consultations among world‐leading researchers in the related research areas. Advantages, limitations and relevance of each method are also discussed. The present consensus provides a revised framework of standardised terms to improve the consistent use of masticatory terminology and facilitate further investigations on masticatory function analysis. In addition, this article also outlines various methods used to evaluate the masticatory process and their advantages and disadvantages in order to help researchers to design their experiments.

Immediately loaded mini-implants supporting mandibular overdentures: A one-year comparative prospective cohort study

BACKGROUND

Little is known about differences between mini-implants and conventional immediately loaded implants for overdentures.

OBJECTIVES

To compare clinical outcomes using two immediately loaded conventional or mini-implants for mandibular overdentures.

MATERIALS AND METHODS

Edentulous patients receiving either conventional (4.1 mm) or mini-implants (2.9 mm or less), based on available bone width were analyzed. All implants were immediately loaded with mandibular overdentures installed using locator attachments. Digital periapical radiographs for measuring marginal bone loss and clinical outcomes (ie, periodontal probing, plaque, and bleeding indices) were assessed at 1, 3, 6, and 12-month follow-up periods.

RESULTS

Fifty patients (25 receiving conventional implants-12 females, mean age of 65.3 ± 7.3 years; and 25 receiving mini-implants-11 females, mean age of 66.8 ± 8.1 years) was analyzed. Peak insertion torque (P = .001) and bone loss (P = .02), as well as change in plaque (P = .02) and bleeding (P = .04) indices at 12 months differed significantly between groups. Furthermore, linear regression revealed the height of the locator as a risk factor for bone loss (P = .038).

CONCLUSIONS

The present findings suggest that two mini-implants are significantly more susceptible to bone loss after immediate loading, for which the height of locator might be considered a risk factor.