A cohort study on short mini-implants for mandibular overdentures compared to those of standard length

Orofacial esthetics, chewing function, and oral health-related quality of life in Kennedy class I patients with mini-implant-retained removable partial dentures: A 3-year clinical prospective study

This prospective clinical study aimed to assess self-reported orofacial esthetics, chewing function, and oral health-related quality of life (OHRQoL) over three years in the Kennedy Class I patients without posterior dentition who received free-end saddle removable partial dentures (RPDs) retained by two mini dental implants (MDIs) inserted in the canine/first premolar region. The study's robust findings reaffirm the viability of MDI-retained RPDs as a treatment modality in contemporary prosthodontics, instilling confidence in the dental community.

MATERIALS AND METHODS

92 participants with posterior edentulism in the maxilla or mandible received 184 MDIs and 92 RPDs. After one year, three participants were excluded, and another seven were excluded after three years. The final sample was 82 participants. Self-perceived orofacial esthetics was assessed by the Orofacial Esthetic Scale (OES), chewing function by the Chewing Function Questionnaire (CFQ), and the OHRQoL by the OHIP-14. Statistical analysis utilized multivariate regression analysis, standardized effect size calculation, Wilcoxon Signed Rank test, and Friedman's test.

RESULTS

OHRQoL and chewing function significantly improved (p < 0.001) one month after MDI loading by the new RPDs and continued to improve over the observation period (p < 0.05). The OES also significantly improved (p < 0.001) and remained almost unchanged over the next three years (p = 0.440).

CONCLUSION

Despite the limitations of this study, the MDI-retained RPD appears to be a viable treatment modality in contemporary prosthodontics from the patients' perspective.

Mandibular Overdenture Supported by Two or Four Unsplinted or Two Splinted Ti-Zr Mini-Implants: In Vitro Study of Peri-Implant and Edentulous Area Strains

Clinical indications for the newly released Ti-Zr (Roxolid®) alloy mini-implants (MDIs) aimed for overdenture (OD) retention in subjects with narrow alveolar ridges are not fully defined. The aim of this study was to analyze peri-implant and posterior edentulous area microstrains utilizing models of the mandible mimicking a "real" mouth situation with two (splinted with a bar or as single units) or four unsplinted Ti-Zr MDIs. The models were virtually designed from a cone beam computed tomography (CBCT) scan of a convenient patient and printed. The artificial mucosa was two millimeters thick. After MDI insertion, the strain gauges were bonded on the oral and vestibular peri-implant sites, and on distal edentulous areas under a denture. After attaching the ODs to MDIs, the ODs were loaded using a metal plate positioned on the first artificial molars (posterior loadings) bilaterally and unilaterally with 50, 100, and 150 N forces, respectively. During anterior loadings, the plate was positioned on the denture's incisors and loaded with 50 and 100 N forces. Each loading was repeated 15 times. The means with standard deviations, and the significance of the differences (two- and three-factor MANOVA) were calculated. Variations in the MDI number, location, and splinting status elicited different microstrains. Higher loading forces elicited higher microstrains. Unilateral loadings elicited higher microstrains than bilateral and anterior loadings, especially on the loading side. Peri-implant microstrains were lower in the four-MDI single-unit model than in both two-MDI models (unsplinted and splinted). Posterior implants showed higher peri-implant microstrains than anterior in the four-MDI model. The splinting of the two-MDI did not have a significant effect on peri-implant microstrains but elicited lower microstrains in the posterior edentulous area. The strains did not exceed the bone reparatory mechanisms, although precaution and additional study should be addressed when two Ti-Zr MDIs support mandibular ODs.

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.

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.

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.

Are Mini Dental Implants Suitable for Support of Crowns or Small Bridges in the Mandibular Incisor Region? A 5-year Longitudinal Study

PURPOSE

It has not been previously studied whether 1-piece category 1 narrow dental implants (≤2.5 mm wide) can successfully support crowns or small bridges. The purpose of this study was to evaluate the long-term benefits of the fixed-type mini dental implants (MDIs) for replacement of mandibular incisors.

MATERIALS AND METHODS

In a prospective cohort study, fixed-type 1-piece MDIs, replacing single or multiple mandibular incisors, supporting metal-ceramic single crowns (unsplinted group), or splinted crowns/small bridges (splinted group) were observed over the period of 5 years. The primary predictor was the splinting status. The primary outcome variables were peri-implant marginal bone level (MBL) change, success, and survival rates (assessed as per Pisa Consensus Conference). The secondary outcomes were dental patient-reported outcome measures (dPROMs) and oral hygiene assessment. Descriptive statistics, Chi-squared test, t-test, Mann-Whitney and Wilcoxon tests, Kaplan-Meier survival analysis, log-rank (Mantel-Cox) comparison, Cox proportional hazard analyses adjusting for number of implants, Spearman correlation, and repeated measures were used for data analysis.

RESULTS

From 44 participants (mean age 56.02 ± 5.72 years), 40 completed the 5-year study: 23 in the splinted and 17 in unsplinted group. Three subjects did not respond, while 1 MDI failed (third year) in the unsplinted group. Mean MBL change in both groups was small; however, it increased over time (-0.22 ± 0.38 mm after 1 year; -0.54 ± 0.56 mm after 5 years; P < .05). After 5 years mean MBL change was -0.59 ± 0.71 mm in the unsplinted and -0.50 ± 0.41 mm in the splinted group (P > .05). Survival analysis revealed no significant difference between the unsplinted (85.7% success, 4.8% failures, and 9.5% satisfactory survivals) and splinted group (93.4% success and 6.6% satisfactory survivals) (P > .05). The group affiliation (unsplinted vs splinted) and number of implants were not significant predictors of MDI failure or survival rates (P > .05). Significant improvement in dPROMs after rehabilitation remained unchanged over 5 years (P > .05). Modified plaque index significantly increased over time, correlating with the MBL loss.

CONCLUSION

MDIs supporting crowns and/or small bridges in the mandibular incisor region showed small rates of marginal bone loss, acceptable success, and survival rates and improved dPROMs over a 5-year observation period.

Adaptation to New Dentures and 5 Years of Clinical Use: A Comparison between Complete Denture and Mini-implant Mandibular Overdenture Patients based on Oral Health-Related Quality of Life (OHRQoL) and Orofacial Esthetics

Objective of work

It is unclear how long patients need to adapt to new dentures. This study assessed adaptation and five years of clinical use, comparing complete denture wearers (CDs) and mini-implant mandibular overdenture wearers opposing a maxillary CD (MDI-OD), based on oral health reported quality of life (OHRQoL) and orofacial esthetics (OES).

Material and Methods

A total of 36 subjects in the CD group (25 females) and 30 subjects in the MDI group (20 females) completed the 5-year study. All patients received new CDs, but in the MDI-OD group, four mini-implants were inserted interforaminally in the mandible before denture manufacture. Participants filled in the OHIP-EDENT and OES questionnaires one day after dentures’ delivery, on the 3^rd, 8^th, 15^th, 30^th day, and at the 1-, 3- and 5-year follow-up examinations. Statistical analysis comprised descriptive methods, X² test, independent t-test, Friedman, and Mann-Whitney test.

Results and Conclusions

Both groups' adaptation to new dentures was completed within a month. The MDI-OD group had significantly better OHRQoL in all follow-ups except for the 3^rd and 8^th day, probably due to soreness and pain, the reason why the MDI-OD group had limitation in functioning in the first days after new dentures’ delivery. Already after the third year and at the fifth year, OHRQoL worsened (p<0.01) in both groups. However it was significantly more pronounced in the conventional CD wearers (p<0.01) than in the MDI-OD group. Orofacial esthetics was highly scored in both groups. The scores dropped down only after three years, equally in both groups.

Keywords

OHRQoL, OES, prospective study, complete dentures, mini-implants, adaptation

MeSH Terms

Complete Dentures; Dental Implants; Quality of Life; Dental Esthetics

Psychometric Characteristics of the Croatian and the Serbian Versions of the Oral Health Impact Profile for Edentulous Subjects, with a Pilot Study on the Dimensionality

Introduction

The aim was to adapt the Croatian and the Serbian versions of the Oral Health Impact Profile for the edentulous population (OHIP-EDENT-CRO and OHIP-EDENT-SRB).

Methods

The translation and cross-cultural adaptation were carried out in accordance with accepted international standards. A total of 95 and 177 removable denture wearers were recruited in Croatia and Serbia respectively. The reliability was evaluated by calculating Cronbach’s alpha coefficient and by test-retest (30 participants in each country). The concurrent validity was determined by calculating the Spearman’s rank coefficient between the OHIP-EDENT summary scores and one question related to removable denture satisfaction. Construct validity was determined by exploratory factor analysis (EFA). Responsiveness was determined by comparison of the OHIP-EDENT summary scores before and after dental implant placement to support mandibular overdentures (23 patients in Croatia, 21 in Serbia).

Results

Cronbach’s alpha coefficient was 0.92 in Croatia and 0.87 in Serbia. The intraclass correlation coefficient was 0.98 in Croatia and 0.94 in Serbia. In Croatia the Spearman’s correlation coefficient was -0.71 (p<0.001) and in Serbia -0.74 (p<0.001). Both confirmed concurrent validity. Construct validity was tested by EFA, which extracted four factors in each country, accounting for 66.59% of the variance in Croatia and 59.33% in Serbia. Responsiveness was confirmed in both countries by a significant OHIP-EDENT summary score reduction and a high standardised effect size (3.9 in Croatia, 1.53 in Serbia).

Conclusion

The results prove that both instruments, the OHIP-EDENT-CRO and the OHIP-EDENT-SRB, have very good psychometric properties for assessing OHRQoL in the edentulous population.

Comparison of different surgical procedures on the stability of dental implants in posterior maxilla: A randomized clinical study

BACKGROUND

Stability of a dental implant is very important when planning immediate loading and design of a final restoration. The aim of this study was to compare the primary and the secondary stability of dental implants inserted by three different surgical techniques: conventional (standard) technique using a sequence of drills for implant bed preparation, osteotome technique using tapered hand instruments for creating implant sites by condensing the bone and guided flapless implant surgery with surgical templates.

MATERIAL AND METHODS

The study included 150 patients (80 males and 70 females), 46-71 years old, who required implant supported fixed partial dentures in the posterior maxilla of D3 or D4 bone density. Patients were randomly assigned into one of the three surgical insertion technique groups. All patients received tapered implants of the same manufacturer of the same length and two different widths (3.3 × 11.5 mm or 4.2 × 11.5 mm). Primary and secondary implant stability were measured by means of resonance frequency analysis (RFA) at the time of implant placement and 5 months after surgery using the Ostell ISQ device (Osstell AB, Sampgatan, Goteborg, Sweden). Statistical analysis included one-sample Kolmogorov Smirnov test, descriptive statistics, multivariate analysis (Bonferoni post-hoc tests) and paired t-tests.

RESULTS

Patients in the osteotome group exhibited higher primary stability (P < 0.01) than in the conventional and surgically guided flapless groups. There were no significant differences in the secondary stability (p >  0.05). Wider implants presented higher ISQ values (P<0.01).

CONCLUSION

The osteotome technique led to the highest implant primary stability, therefore it can be recommended when immediate loading is planned or for one-piece implant insertion.

Marginal Bone Level Changes and Oral Health Impact Profile (14) Score of Smokers Treated by Mandibular Mini Implant Overdentures: A 5-Year Follow-up Study

Objectives  Studies considered edentulous patients having smoking habit as a compromised oral condition. This research examined the value of using mini implant mandibular overdenture to maintain long-term satisfactory levels of oral health quality of life and marginal vertical bone loss.

Materials and Methods  Twenty-nine edentulous patients with smoking habit received four mini implants in the mandible loaded by overdentures. The present study monitored patients radiographically for vertical bone loss after (1 month, 1, 3, and 5 years) of treatment. Patients were also evaluated by oral health impact profile 14 (OHIP-14) pretreatment and at 1 and 5 years of treatment.

Statistical Analysis  Repeated measure analysis of variance with Bonferroni’s test as a post-hoc test was used to see the difference among time points. Independent sample t -tests were used to compare between anterior and posterior mini implant positions after 5 years of follow-up. OHIP-14 questionnaire was analyzed by Wilcoxon signed ranks for pairwise comparisons at different evaluation times. A Holm-Bonferroni correction method was used to control the familywise error rate.

Results  The mean of the bone height changes showed a significant difference between 1-month data and all other evaluation intervals while no significance was calculated among other evaluation intervals. Bone loss of the mini implants placed anteriorly was less than those placed posteriorly with a statistically significant difference. A significant reduction in the OHIP-14 score levels was observed between pretreatment and both 1 and 5 years of treatment. No significance was seen between the first and fifth year after treatment.

Conclusion  Mini implant overdenture could maintain satisfactory marginal bone level changes and oral health quality of life for patients with smoking habit after 5-year follow-up period.