Masticatory Function with Implant-supported Overdentures

Four-year assessment of masticatory function in mandibular overdenture wearers: A randomised clinical trial comparing two to four implants to retain the prosthesis

BACKGROUND

Limited data exist on the mid- to long-term masticatory capacity of mandibular overdenture (IOD) wearers, particularly regarding the use of posterior implants to retention.

OBJECTIVES

To periodically evaluate mastication of IOD wearers, comparing the effectiveness of two to four implants to retain the prosthesis.

METHODS

In a randomised controlled clinical trial, 20 complete edentulous patients (14 women), aged 51-84 years (mean age 69.1 ± 9.6), received new bimaxillary complete dentures (CD). After adaptation, baseline measurements of masticatory performance (X50) and swallowing threshold were conducted using the sieving method. Patients were then randomly assigned to groups: control (two intra-foraminal regular implants) and experimental (two intra-foraminal regular implants and two extra-short posterior implants) (n = 10 each). After 4 months, implants were splinted, and a new mandibular IOD was fabricated with bar/clip retention. Mastication was reassessed after 6, 12, and 48 months, and data analysed with repeated measures ANOVA and Sidak's post hoc (α = 0.05).

RESULTS

Despite a loss of two patients per group, masticatory performance significantly improved after mandibular IOD installation (p = .031) in both groups (p = .670). A second improvement was observed after 6 months (p = .027), with no subsequent changes (p > .05). Swallowing threshold improvements were noted with IOD, and no discernible differences between groups were observed (p > .05).

CONCLUSION

Masticatory function significantly improved after mandibular IOD installation, with the number of implants demonstrating minimal influence.

CLINICAL TRIAL REGISTRATION

The present study was not registered in a public database, as mandated. It is important to note that the recommendation for registration was initiated in 2017 by the Committee of Medical Journal Editors, while patient inclusion in the research took place in 2016. Given that the data presented in this manuscript cover a follow-up period of up to 4 years post-surgical intervention, delayed registration was not feasible.

Masticatory function in edentulous patients wearing implant overdentures after graftless maxillary sinus membrane elevation

BACKGROUND

Graftless sinus floor augmentation shows good results in bone gain, radiology and implant survival. Clinically, this technique can be recommended as an alternative to conventional procedures using augmentation materials.

OBJECTIVES

This study aims to assess masticatory performance, masticatory ability and patient satisfaction after graftless sinus floor augmentation.

METHODS

The study group consisted of patients who had received a graftless sinus lift procedure in a split-mouth design and was compared to patients with maxillary implant-supported overdentures without augmentation and a natural dentition group. To assess objective masticatory performance, the mixing ability test was performed. Three questionnaires were used to assess patient reported outcomes related to mastication and patient satisfaction.

RESULTS

Each group included ten patients. Both the graftless sinus lift group and the edentulous control group had a worse masticatory performance compared to the natural dentition group. Masticatory ability, measured by patient reported outcomes, was not different between the graftless sinus floor augmentation group and implant-retained overdentures group without augmentation, but the natural dentition group showed better results. Thereby, the better the masticatory performance in patients with a graftless sinus membrane elevation the better the patient satisfaction for 'prosthesis', 'appearance of prostheses', 'speech' and 'mastication and eating'.

CONCLUSIONS

Patients with implant-supported overdentures show inferior masticatory function compared to those with natural dentition. There were no significant differences in masticatory performance between patients with implant-retained overdentures, with or without graftless augmentation. The decision on the preferred procedure should consider additional factors such as anatomical, surgical-technical aspects and patient's preferences.

Effect of dental implant therapy on the preservation of orofacial tissues: A systematic review and meta-analysis

OBJECTIVE

Fundamentally, this review addresses the following question: In partially or fully edentulous patients, do implant-supported dental prostheses preserve orofacial tissues when compared to conventional prostheses or no therapy?

MATERIALS AND METHODS

This study was conducted according to the 2020 PRISMA guidelines for systematic reviews. Electronic searches were conducted at PubMed and Embase databases followed by manual search. Clinical studies comparing the effect of implant-supported prostheses with conventional rehabilitation or no treatment on alveolar bone resorption, remaining teeth, and jaw muscle thickness were considered for inclusion. A qualitative synthesis was conducted with all included studies, and data from selected studies were pooled quantitatively to perform a meta-analysis.

RESULTS

A total of 14 studies were selected for analysis. Six studies reported on the effect of implant therapy on alveolar bone resorption (n = 453), six on the remaining teeth (n = 1014), while four studies evaluated masseter muscle thickness (n = 158). The results of the meta-analyses assessing alveolar bone resorption in the posterior mandible and in the anterior area of the maxilla, both fixed and random effects models, yielded no benefit of rehabilitation with implant-supported prostheses when compared to conventional prostheses. For masseter bone thickness, however, a significant benefit for implant-supported prosthesis was observed.

CONCLUSIONS

This systematic review and meta-analysis were unable to unequivocally answer the focus question. There are some indicators of the benefit of implant-supported prostheses over conventional prostheses or no therapy in preserving orofacial tissues, particularly for masseter muscle thickness. However, the evidence is still insufficient to confirm such perception.

Oral function in completely edentulous patients rehabilitated with implant-supported dental prostheses: A systematic review and meta-analysis

OBJECTIVES

This review evaluated the effects of rehabilitation with implant-supported prostheses on the oral function of completely edentulous adults.

MATERIALS AND METHODS

Systematic literature searches were performed to identify records reporting on oral function in completely edentulous adults rehabilitated with implant-supported prostheses. Meta-analyses were performed on various outcomes including bite force, masticatory performance, muscle activity, mandibular movement/chewing pattern, and salivary flow.

RESULTS

5507 records were identified. Thirty studies qualified for data extraction and analysis. The kappa (𝛋) for the search and identification strategy ranged between 0.50 and 1.00. Meta-analysis was performed grouping the studies by outcomes and split by time points of 6-12 months, 12-36 months, and >36 months after implant therapy. The meta-analyses revealed a significant improvement in oral function of completely edentulous adults after rehabilitation with implant-supported prostheses at 6-12 months (Z = -4.895, p < .001; 95% CI: -0.703, -0.301; τ2  = .609; Q = 114.953, df = 17, p < .001; I2  = 85.2%), at 12-36 months (Z = -4.886, p < .001; 95% CI: -0.580, -0.248; τ2  = .908; Q = 280.611, df = 35, p < .001; I2  = 87.5%) and at more than 36 months (Z = -9.108, p < .001; 95% CI: -1.472, -0.951; τ2  = .019; Q = 7.918, df = 7, p = .340; I2  = 11.6%). The included studies demonstrated a low to moderate risk of bias.

CONCLUSIONS

This systematic review concluded that the oral function of completely edentate adults significantly improved with implant-supported/retained prostheses, even when only one jaw received implant therapy. Therefore, implant therapy should be promoted for edentulous adults to alleviate the shortcomings of conventional complete removable dental prostheses.

A systematic review and meta-analysis of the clinical performance of implant-supported overdentures retained by CAD-CAM bars

Currently, there is no consensus on the indications and clinical performance of implant-supported overdentures (IODs) involving computer-aided design and manufacturing (CAD-CAM) bars.

OBJECTIVE

To evaluate the performance of IODs involving CAD-CAM bars.

METHODOLOGY

A comprehensive search of studies published until May 2023 was conducted in many databases, including PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The population, intervention, comparison, outcome (PICO) question was: "How do IODs retained by bars fabricated by CAD-CAM technology perform in daily clinical practice?" The meta-analysis included clinical studies based on effect size and a two-tailed null test with a 95% confidence interval (CI).

RESULTS

Ten studies were included in the meta-analysis. Among them, nine reported a 100% implant survival rate for all CAD-CAM milled bars. Complications were reported in two studies with CAD/CAM-milled titanium bars, and one study reported more fractures in soldered gold bars used in maxillary rehabilitation. However, no fractures were observed in IODs retained by PEEK and zirconia bars. According to six studies, biological complications, including peri-implantitis, were minimal in the BioHPP and PEEK bar groups, while no cases were reported in the titanium or zirconia bar groups. CAD-CAM-milled zirconia bars had higher plaque and bleeding indices compared with titanium bars, as evidenced by findings from five studies. All four studies that evaluated Oral Health Impact Profile (OHIP) scores showed a positive effect of IODs retained by CAD-CAM milled titanium bars on quality of life. Patient satisfaction and acceptance by prosthodontists were significantly high, according to the results of five studies.

CONCLUSION

Overdentures retained with CAD-CAM milled titanium bars show great potential for use in daily clinical practice. Moreover, patient and practitioner satisfaction was very high when this method was used.

Outcome of healing after dental implant placement in patients with cancer on high-dose antiresorptive medications: a prospective feasibility study

PURPOSE

Implant placement in patients with cancer receiving high-dose antiresorptive medication (HDAR) is considered contraindicated. This prospective, feasibility study tested the hypothesis that dental implants can be placed in such patients by applying a staged implant placement protocol with submerged healing.

METHODS

Three groups of patients on HDAR were included as follows: group 1: patients who underwent tooth extraction, without the development of medication-related osteonecrosis of the jaws (MRONJ); group 2: patients with surgically treated MRONJ who had demonstrated clinical healing for at least 3 months; group 3: patients with established MRONJ who was planned for surgical resection and simultaneous implant placement.

RESULTS

A total of 49 implants were placed in 27 patients (group 1: 12, group 2: 7 and group 3: 8). HDAR included bisphosphonates and denosumab. The mean HDAR time was 25 months (SD: ± 18.4, range 3-68 months). An abutment operation was performed 4 months following the implant placement (SD: ± 1.9, range 3-14 months). All patients healed uneventfully.

CONCLUSIONS

This study demonstrated that it is feasible to insert dental implants and perform an abutment surgery in patients with cancer on HDAR, without the development of MRONJ.

CLINICALTRIALS

gov Identifier: NCT04741906.

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.

Thermal Cycling Effect on Locator System Retention and Metal Surface Roughness

PURPOSE

To estimate the effects of the thermal cycling (TC) process on the metal surfaces of Locators, as well as retention loss, and the correlation between them.

MATERIALS AND METHODS

Twenty-five new Locator R-Tx were included in the study. Four areas were marked on each Locators' patrix metal surface and scanned using a confocal scanner (μsurf explorer; NanoFocus). Three surface roughness parameters were measured in the scans: Sa (average distance of peaks from the central plain of the area), Vmp (volume of the peaks in the area), and Spc (mean curvature of the peaks describing the degree of their sharpness). Retention test was performed using Instron® 4500 compression tension tensile tester at a speed of 10 mm/min. The retention tests were done using a working model made of two acrylic blocks in which the Locator system parts were inserted. The surface parameters measurements and the retention tests were performed 2 times, once before and once after TC. The Locators were subjected to 15,000 TC cycles by investing them into 2 tubs with different water temperatures, 55°C and 5°C. During each 60-second cycle, the Locators were submerged in each tub for 20 seconds, with a 10 second transition time between the tubs. The post-TC retention and surface parameters measurements were compared with those prior to TC and the prior to TC measurements served as controls. Changes in parameters before and after TC were analyzed by a two-way ANOVA nested model with random intercept and slope by restricted maximum likelihood method. Correlation between retention and surface parameters was quantified and examined using Kendall's correlation test. The findings were considered statistically significant if p < 0.05.

RESULTS

There was a significant decrease in retention of 16.6N at the second retention test (p < 0.001). A significant statistical decrease in surface parameters were measured after TC process, Sa and Vmp (18 ×10^-3 μm, p = 0.041 and 0.94 ×10^-3 1/μm, p = 0.001, respectively). A significant statistical increase in Spc of 6.4 ×10^-3 μm³ /μm² (p = 0.023) was noticed. The correlation between retention decreases and surface changes was not statistically significant.

CONCLUSION

The TC process causes a substantial reduction in retention to the Locator system over time. In addition, TC causes significant but minor changes to the Locator surface area. Most of the changes are in the horizontal dimension.

Tissue Surface Adaptation and Clinical Performance of CAD-CAM Milled versus Conventional Implant-Assisted Mandibular Overdenture

Purpose

To evaluate the surface adaptation and maximal biting force of CAD-CAM milled mandibular overdenture (CAD-CAM MOD) compared to conventional compression mold mandibular overdenture (CC MOD).

Materials and Methods

Ten completely edentulous subjects with persistent complaints of their complete mandibular dentures were received four dental implants in the anterior mandible. Three months after osseointegration, subjects were randomly received either conventional compression mold or CAD-CAM MOD in a crossover design. To assess tissue surface adaptation, the fitting surfaces of each denture base were scanned and placed on the reference master cast. Three and six months after each overdenture was inserted, clinical performance in the form of maximum biting force was evaluated.

Results

The results of this study indicated that the tissue surface adaptation of the CAD-CAM MOD bases was significantly better than the conventional (compression mold technique) processed bases where (P=0.0001). Regarding clinical performance (maximum biting force), the CAD-CAM MOD exhibited better clinical performance (P=0.0001).

Conclusions

In denture processing methods, the CAD-CAM overdenture delivered more precise adaption and clinical performance than the compression mold technique.

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.

Evaluation of patient satisfaction and masticatory performance in mandible single implant-assisted overdenture

Objectives

Many authors' have advocated a minimum of two implants to support a mandibular overdenture, but financial restraints specifically among the geriatric population in developing countries made this treatment plan economically difficult. Hence, this study was planned to assess the symphyseal (midline) single implant-assisted complete overdenture for patient satisfaction and masticatory performance.

Materials and Methods

In this clinical study, 12 edentulous first-time denture wearers underwent placement of a single implant in the mandibular symphyseal region. After 1 week, new complete dentures were fabricated and delivered to the patients. Post 3 months, the denture was fixed with a nylon cap-ball attachment to the anchor implant. Patients were questioned about comparison in the level of satisfaction and complaint before loading the implant (control group) and after 1 week, 1 month, and 3 months. The implant-assisted overdenture was fabricated with the help of a questionnaire. Masticatory performance was calculated with the help of a bite force measuring device at the same time intervals. SPSS 17.0 statistical software was used to analyze the data.

Results

It was found that single implant anchorage of the mandibular complete denture resulted in a significant increase (P < 0.05) in patient's subjective satisfaction and a decrease (P < 0.05) in complaints at the end of 3 months. There was a significant (P < 0.01) increase in bite force in implant overdenture after 3 months (5.459 kgf) as compared to that of the complete denture (3.406 kgf).

Conclusion

Single implant-assisted overdenture can be an appropriate treatment modality to treat edentulousness in the geriatric population. It insinuates the remarkable improvement of prosthesis function and oral comfort with minor surgical procedures.

Masticatory function in elderly compared to young adults

PURPOSE

To characterize the masticatory function of the elderly and to compare total amount of time, masticatory strokes and total mastication score among the elderly and young adults.

METHODS

It is an observational, cross-sectional and analytical study. A total of 50 individuals participated, 25 elderly (mean age 66 years) and 25 young adults (mean age 22 years). The evaluation of mastication was performed by standardized filming of the usual mastication of a wheat flour biscuit. The masticatory type (alternated bilateral, simultaneous bilateral, preferential unilateral, chronic and anterior), masticatory score, total masticatory time and the total number of masticatory strokes were verified and compared between the elderly and young adults.

RESULTS

The predominant masticatory pattern in the young adults was the alternated bilateral mastication (52%), while, in the elderly, the simultaneous bilateral mastication predominated (48%). The use of dental prostheses had a significant influence on the total mastication score; elderly presented greater masticatory time and greater amount of masticatory strokes; however, the total masticatory score was lower for this group.

CONCLUSION

The use of dental prosthesis has a significant influence on masticatory function. When compared to young adults, the elderly had a greater amount of time and masticatory strokes and a lower total mastication score.

CAD-CAM complete removable dental prostheses: A double-blind, randomized, crossover clinical trial evaluating milled and 3D-printed dentures

OBJECTIVE

This double-blind, randomized, crossover, clinical trial aimed to evaluate and compare the differences between milled and 3D-printed complete removable dental prostheses (CRDPs).

METHODS

Fifteen edentulous patients (men: n = 10, women: n = 5; age: 66.7 ± 8.0 years) rehabilitated with conventional CRDPs were recruited for this trial. Participants were randomized to first receiving either the milled or 3D-printed CAD-CAM manufactured CRDPs and then after 6-weeks cross over to the other set. Both, clinicians and participants were blinded to the group allocation. Outcomes included patient's denture satisfaction (PDS), oral-health related quality of life (OHIP-EDENT), willingness-to-pay analysis, final choice (FC) of CRDPs, clinician's denture quality evaluation (CDQE), chewing efficiency (CE), maximum-voluntary-bite-force (MBF), and prosthodontic maintenance needs. The outcomes were measured at baseline (with old CRDPs), at 1 and 6 weeks after new CRDP insertion; following crossover with the second set of CRDPs, an identical protocol was followed. Generalized linear regression for repeated measures was used for statistical analysis with α=0.05.

RESULTS

All participants completed the trial. 3D-printed CRDPs required more maintenance visits, adjustment time (p = 0.0003), and adjustment costs (p = 0.021). Patients were willing-to-pay an average of 606.67 Swiss Francs more than the actual cost for the milled CRDPs. There were no differences in the PDS, OHIP, FC, CDQE, CE, and MBF between the two CRDPs groups.

CONCLUSIONS

The findings of this double-blind randomized crossover clinical trial confirm that both milled and 3D-printed CRDPs are valid treatment modalities for edentulous patients, with the latter performing inferiorly with regard to the time and costs involved with the prosthodontic aftercare, as well as the patients' willingness-to-pay.

CLINICAL RELEVANCE

The findings of this trial provide evidence to help the clinician in choosing the appropriate CAD-CAM manufacturing process for fabricating the CRDPs.

Assessment of masticatory function in older individuals with bimaxillary implant-supported fixed prostheses or with a natural dentition: A case-control study

STATEMENT OF PROBLEM

A clinical assessment of the masticatory performance of edentulous people treated with bimaxillary implant-supported fixed prostheses is lacking.

PURPOSE

The purpose of this case-control study was to compare the masticatory performance of edentulous people treated with bimaxillary implant-supported fixed prostheses to that of those with a natural dentition by using a simplified comminution test with hard viscoelastic test food and a mixing ability test.

MATERIAL AND METHODS

Thirty-six participants were recruited and divided into 2 equal groups (n=18) based on their dental status. The experimental group (7 women, mean ±standard deviation age=69.8 ±7.5 years) had bimaxillary implant-supported fixed prostheses, and the control group (9 women, mean ±standard deviation age=68.3 ±5.6 years) had a natural dentition. A hard viscoelastic food comminution test and a mixing ability test with 2-colored chewing gum were performed in both groups. The number and total area of the particles during the comminution test and the variance of hue during the mixing ability test were measured. The data were analyzed with the parametric (paired t test) and nonparametric (Mann-Whitney U) tests to assess differences between the groups (α=.05).

RESULTS

The experimental group exhibited significantly fewer pieces in the food comminution test than the control group (P=.001). The experimental group also showed significantly higher variance of hue values than the control group (P<.001).

CONCLUSIONS

Patients treated with bimaxillary implant-supported prostheses had reduced masticatory performance in comparison to those with a natural dentition, despite having been provided with satisfactory and well-functioning prostheses.

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.

Repercussion of Conventional Complete Mandibular Denture Versus Single Implant Over-Denture on Retention and Biting Force

Aim: Aim of this study was the evaluate the retention and biting force of conventional complete denture and after placement of a single implant in the mandible for an implant retained over-denture Material and methods Eight completely edentulous patients were selected. A single implant was inserted at the symphysis of the mandible and left to osseointergrate. During the osseointegration period a conventional complete denture was fabricated and inserted. Retention and biting force was measured at insertion and after 3 months of service. After osseointegration attachment was connected, space was formed in the fitting surface of the existing mandibular denture and retention silicon was placed. Retention and biting force were measured at insertion and after 3 months follow-up. Data were collected and statistically analyzed. Results: The retention mean values for the complete denture was 2.420±0.360, however the retention mean values for the single implant over-denture was 6.395±0.289.  F=3.80 with statically significance difference between the groups of P <0.01. The biting force mean values for the complete denture was 52.62±2.71, however the biting force mean values for single implant over-denture was 71.45±2.73. F= 1.790 with statically insignificance difference between the groups of P >0.01 Conclusion: Single implant overdenture improved the retention and the biting force when compared with the complete denture, this has improved the quality of life and happiness.

Masticatory performances and maximum occlusal forces of immediate and conventional loaded two-implant supported overdentures retained by magnetic attachments: preliminary study of randomized controlled clinical trial

Background

The appropriate loading protocol to improve masticatory performance (MP) is still unclear in elderly patients and two-implant overdentures (2-IODs) wearers. This study aimed to compare the long-term MP and maximum occlusal force of immediate loading (IL) and conventional loading (CL) of 2-IODs retained by magnetic attachments. Nineteen edentulous patients were randomly assigned to either an IL (n=10) or CL group (n = 9). In the IL group, the implant was loaded on the same day as insertion, whereas it was loaded 3 months after insertion in the CL group. Magnetic attachments were used to retain all overdentures to the implants. MP, measured by a piece of color-changeable chewing gum and a gummy jelly test, and maximum occlusal force, measured using an occlusal force measuring device, were assessed in both groups at baseline and at 3-, 4-, and 5-year follow-ups.

Results

No significant differences were observed in the MP and the maximum occlusal force between the IL and CL groups at any time point. However, a significantly higher MP was observed at the 3-year time point in the IL group (P = 0.036). The maximum occlusal force revealed a significant correlation with MP, both with the color-changeable chewing gum and gummy jelly at 5 years.

Conclusion

After long-term observation, no significant differences in MP and maximum occlusal force were observed between the IL and CL groups. However, compared to pre-implant insertion of the complete denture, the MP in the IL group significantly improved at 3 years. Furthermore, the maximum occlusal force was significantly correlated with MP at 5 years.

Trial registration

UMIN, UMIN000009889. Registered on 28 January 2013.

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.

Patient satisfaction and masticatory performance of zirconia bar compared to cobalt chromium bar retaining mandibular implant overdenture: A crossover study

OBJECTIVES

The aim of this crossover clinical study was the evaluation and comparison of patient satisfaction and masticatory performance for patients rehabilitated with mandibular two implant overdentures retained with two different bar attachments: zirconia bar and cobalt chromium bar.

MATERIAL AND METHODS

Twenty completely edentulous patients were divided into two equal groups: Group I (ZrO2), each patient received mandibular implant overdenture retained with CAD/CAM zirconia bar on two implants in the canine region, and Group II (Co-Cr), each patient received mandibular overdenture retained with conventional casted cobalt chromium metal bar. Patient satisfaction was measured with a survey questionnaire (PSQ-18), and masticatory performance was also evaluated with the two-colour mixing ability test after 3 months of overdenture insertion; then, each patient received a bar attachment from the other type and evaluations were repeated.

RESULTS

Significant differences were observed regarding psychological acceptance (appearance), time, hygiene, undergo procedures, recommend procedures and the overall experience. In contrast, insignificant difference was observed regarding speech, chewing capacity, restorative procedures, complications and information prior to treatment. No significant difference was reported when comparing chewing performance between the two types of bar attachment.

CONCLUSION

Within this clinical study limitations, patient satisfaction with zirconia bar was higher than Co-Cr bar in terms of appearance, time, hygiene, undergo procedures, recommend procedures and the overall experience. Zirconia can become a suitable alternative to cobalt chromium alloys as a bar attachment. Combining the advantages of implant supported overdenture, CAD/CAM zirconia bar as an attachment, a satisfactory non-metal prosthesis could be provided.

Do implant-supported prostheses affect bioavailability of nutrients of complete and partially edentulous patients? A systematic review with meta-analysis

BACKGROUND & AIMS

Debate still exists about the impact of dental implant-supported prostheses on nutritional status of partially and complete edentulous patients. This review aims to answer the focused question: "Do complete and partial edentulous patients, using implant-supported prostheses, present better nutritional and masticatory functions when compared to those using conventional rehabilitations?". A possible cause-effect relationship between masticatory improvements and nutritional gain was also evaluated.

METHODS

Literature search included 6 databases (PubMed/Medline, Embase, LILACS, Scopus, Web of Science, and The Cochrane Library - CENTRAL), grey literature (Google Scholar, Proquest Dissertations and Thesis and Open Grey databases) and manual search (last update June 2020), without language, publication time and follow-up restrictions. We included only studies evaluating both masticatory and nutritional outcomes. The PICO question comprised complete and partial edentulous patients (Population), submitted to implant-supported prostheses (Intervention), in comparison to conventional dental prosthetic rehabilitation, evaluating masticatory function and nutrition parameters (outcomes). Risk of bias was assessed by using Cochrane Collaboration's tool (randomized clinical trials), Joanna Briggs Institute critical appraisal checklist (paired clinical trials), and Meta-Analysis of Statistics Assessment and Review Instrument" (JBI - MAStARI) critical appraisal tools (cohort studies). All meta-analyses were conducted at 5% level of significance. This report followed the PRISMA guidelines. (Review registration PROSPERO - CRD42019135744).

RESULTS

We identified 1199 articles while searching databases. Fourteen articles met eligibility criteria, including 817 prostheses installed in 660 patients (mean age = 66.8 years-old). Patients wearing implant overdentures (IOD) presented better masticatory function in comparison to conventional complete denture (CD) wearers (p < 0.05). However, bioavailability of several nutrients remained within the same range, except for serum folate that was lower in IOD patients after 6 (mean difference 3.51 nmol/L; p = 0.01) and 12 months of rehabilitation (mean difference 3.69 nmol/L; p = 0.003). When comparing the effects of CD and IOD rehabilitations along time (for the same patient), serum albumin and vitamin B12 levels also decreased for both groups after 12 months-follow-up, but still within the reference range. The additional retention of the implants did not interfere in body weight, but reduced the risk of malnutrition (using the Mini Nutritional Assessment). Implant-supported partial prostheses also improved mastication in comparison to the conventional ones, increasing short-term daily intake of carbohydrates, protein, calcium, fiber, and iron, whereas decreasing the consumption of cholesterol. However, no long-term changes on bioavailability of most nutrients were observed, expect for a slight increase in ferritin and cholinesterase, and a small reduction in folate and Vitamin A.

CONCLUSION

Current evidence indicates significant masticatory improvements for dental fixed implant-supported prostheses in comparison to conventional removable prostheses. However, bioavailability remained stable for most of the nutrients, especially for complete edentulous patients. These results indicate the importance of a multidisciplinary approach during oral rehabilitation (nutrient specialist), in order to enhance food choices and promote health benefits to the patients.

Influence of Facial Morphology on Masticatory Function and Quality of Life in Elders Using Mandibular Overdentures: 3-Year Results

Background: Facial types may interfere in the oral health-related quality of life (OHRQoL) and masticatory performance of implant-retained mandibular overdenture (IMO) wearers.

Purpose: Investigate the medium-term changes in the masticatory function (MF) and OHRQoL parameters of IMO users, as a function of facial pattern, anteroposterior skeletal discrepancy, and sex.

Methods: Forty IMO users, most of them Caucasian (90%) with average age of 69.17 years were classified according to their facial pattern and antero-posterior discrepancy prior to rehabilitation. MF was evaluated by the multiple sieves method to determine the average particle size (X50), heterogeneity (B) and masticatory efficiency (ME, calculated as the percentage of material retained in the 5.6 and 2.8 mm sieves), using Masticatory performance (MP) and swallowing threshold (ST) tests. OHRQoL was measured by applying the dental impact on daily life (DIDL) questionnaire. The data were analyzed by Wilcoxon-paired tests to analyze changes in MF parameters over time, and mixed-effect multilevel regression models were employed to verify differences between groups.

Results: Significant changes were still observed in the 3rd year for the ST test with improvements in B for Mesofacial and in time for Dolichofacial individuals, while ME_2.8 deteriorated for Brachyfacial participants. B values of Class I and male individuals improved and brachyfacial individuals still presented worse homogenization (B) than Mesofacial participants in both masticatory tests. Class II and III participants still showed improvements in ME_5.6 and time compared to Class I despite increases in X50. Class II individuals needed less cycles than Class I in the 3rd year. Brachyfacial participants scored lower in the Appearance domain than Mesofacial ones in the 3rd year. Dolichofacial participants and Class III patients scored lower in the Oral Comfort domain than Mesofacial and Class I, respectively. In addition, age influenced the Pain, Oral Comfort and General Performance domains in the 3rd year.

Conclusions: Differences in facial morphology continue to influence the MF and OHRQoL outcomes in the 3rd year, and age influenced some OHRQoL domains. Brachyfacial individuals continue to benefit least from rehabilitation with IMO according to masticatory parameters.

Mandibular two-implant overdentures with CAD-CAM milled bars with distal extensions or retentive anchors: A randomized controlled trial

OBJECTIVE

This randomized controlled trial (RCT) aimed to demonstrate the non-inferiority of mandibular 2-implant overdentures (IODs) on a CAD-CAM milled bar with long distal extensions (MBDE) against IODs on retentive anchors (RA).

METHODS

Forty edentulous participants rehabilitated with a maxillary conventional denture and a mandibular 2-IOD participated in this trial. They were randomized into two groups [Control group (CG): RA + gold matrices; Experimental group (EG): MBDE + gold clip]. The outcomes included implant survival rate (ISR), chewing efficiency [quantitative (VoH) and subjective (SA) assessments], peri-implant marginal bone levels (PI-MBL), maximum bite force (MBF), and patient-reported outcomes [oral health impact profile (OHIP-EDENT), and denture satisfaction index (DSI)]. Outcomes were recorded at baseline (BL), two weeks (T₀ ), 6 months (T₁ ), and at 1 year (T₂ ) after the intervention. Intra- and inter-group analyses were performed using regression models with ⍺=0.05.

RESULTS

38 participants completed the T₂ visit (CG: n = 19, age = 74.7 ± 7.8 years; EG: n = 19, age = 70.3 ± 10.7 years). At T₂ , there was no implant loss in either of the groups (ISR = 100%). There were no significant differences between the groups for the PI-MBL changes (p = .754). Improvements occurred faster in the EG than in the CG, but over the observation time, there were no differences between the trial groups for VoH, MBF, OHIP-EDENT, and the DSI, except for SA being significantly better in the EG group (p = .022).

CONCLUSIONS

The results of this RCT confirm that mandibular 2-IODs with a CAD-CAM milled bar with long distal extensions are not an inferior treatment to the conventional IODs on retentive anchors in the short term (1 year).

Evaluation of Bite Force and Masticatory Performance: Complete Denture vs Mandibular Overdenture Users

This cross-sectional observational study with 24 patients evaluated differences in bite force (BF) and masticatory performance (MP) between conventional complete denture (CCD) and implant mandibular overdenture (IMO) users and the correlation between these variables. The BF test was performed bilaterally with an occlusal force device. During the MP test, patients were asked to chew Optocal particles for 40 cycles. The Shapiro Wilk test was employed to verify the normality of the data, the student t test to identify differences between groups, and Pearson's correlation to investigate interrelationships between variables. A multiple linear regression was subsequently performed via the stepwise method. P values ≤0.05 were considered statistically significant. Unlike IMO users, CCD users presented a significant difference (25.6%) in BF between the dominant and non-dominant chewing side (p=0.04). IMO users presented significantly higher BF (p=0.01) without presenting a dominant side (p=0.38), and also performed significantly better for the following MP parameters: MPX50 values decreased by 27.25% in IMO users (p=0.01), MPB decreased by 48.38% (p=0.01), and ME 5.6 decreased by 53.25% (p=0.02), while ME2.8 increased by 151.57% (p=0.01). The BF and MPX50 in the IMO wearers group were negatively correlated (-0.57; p=0.05); this correlation coefficient was the only parameter included in the multivariate regression model. IMO users have higher BF and better masticatory performance than CCD users, especially in terms of chewed particles size reduction. MP is correlated with a higher BF in IMO users through better particle trituration.

Microbiological evaluation of LOCATOR® Legacy attachments: A cross-sectional clinical study

Objective

This retrospective cross‐sectional study aimed to evaluate quantitatively the oral microbiome in the tri‐lobe central cavity of Locator Legacy attachment and verify whether it harbors a different, potentially more pathogenic, bacterial spectrum than the adjacent edentulous ridge.

Materials and Methods

Edentulous patients rehabilitated with implant overdentures using Locator Legacy attachments were recruited for this study. The clinical examination comprised probing depths, mobility, peri‐implant, and periodontal health along with intraoral swabs for microbiological evaluation, polymerase chain reaction (PCR) testing, and candida culture. The swabs were collected from the trilobed cavity of the attachment and the adjacent edentulous ridge. PCR was performed to detect six specific bacteria, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, Prevotella intermedia, and Parvimonas micra. Statistical analyses were performed using McNemar's test and Wilcoxon's rank sum test with the significance set to p < .05.

Results

A total of 50 participants with a mean age of 71.5 ± 9.6 years participated in the study. No significant differences in the microbiome were found between samples from the ridge and the attachment. No significantly different numbers in the candida cultures were identified, and the presence of a removable prostheses did not demonstrate a significant association with the prevalence of candida.

Conclusions

Within the limits of this study and the investigated bacterial species, the trilobed cavity of the attachment does not seem to increase the bacterial load.

Implant overdentures retained by self-aligning stud-type attachments: A clinical report

The functionality of a new overdenture attachment (LOCATOR R-Tx) was described for different clinical situations: a conventional mandibular implant overdenture (IOD) retained by 2 implants, a straightforward chairside maintenance procedure for replacing a worn LOCATOR (Legacy) attachment with the new LOCATOR R-Tx, and a complex clinical situation with nonideal implant positions with compromised parallelism. The LOCATOR R-Tx is an advance on the existing LOCATOR Legacy attachment and has an improved abutment head design with a more durable surface coating to prevent attachment wear and thereby reduce frequency of maintenance.

A prospective cohort study on survival and success of one-piece mini-implants with associated changes in oral function: Five-year outcomes

OBJECTIVE

To investigate in a prospective cohort study the 5-year post-loading survival and success of one-piece mini dental implants (MDIs) in edentulous subjects with mandibular implant overdentures (IODs) and to report the associated changes of oral function with respect to patient age.

MATERIALS AND METHODS

Independently living edentulous patients were recruited and provided with new complete dentures. After an adaptation period, four one-piece MDIs (diameter 1.8 mm) were installed in the interforaminal region and immediately loaded. At baseline pre-operative (BL), as well as at 1-year and 5-year follow-up examinations, chewing efficiency was assessed with a validated color-mixing ability test and maximum voluntary bite force (MBF) was recorded with a digital force gauge. Implant survival and success were evaluated at 5-year follow-up. Non-parametric tests served to analyze the differences between time points.

RESULTS

Twenty patients participated in the study (5 men and 15 women; age at BL: n = 10 ≤ 65 years and n = 10 > 65 years). All patients were available for a 5-year follow-up (n = 2 in their long-term care facility; n = 1 only by telephone). The survival and success rates were both 100% after 61 ± 5.7 months. Chewing efficiency did not change over the first year (p = 0.167), but was improved at 5 year fup (n = 19) compared to baseline (p = 0.033) and to 1 year (p < 0.001). The MBF (n = 19 at 5-year follow-up) increased continuously over time (p < 0.001), but was less pronounced in the older cohort (p = 0.009).

CONCLUSIONS

Mini dental implants seem to be a successful treatment option for edentulous elderly patients with very high survival and success rates, and serve to improve long-term oral function.

Sensorial Ability, Mastication and Nutrition of Single-Implant Overdentures Wearers

Abstract The use of two-implant overdentures improves mastication of edentulous elderly patients. However, little is known about the effects of single-implant overdentures (SIO) on oral perception and masticatory function in such elders. This study compared the effects of conventional complete dentures (CD) and SIO on the oral sensorimotor ability (OSA), masticatory function, and nutritional intake of elderly people with residual alveolar mandibular height classified as Class III or IV according to the American College of Prosthodontics. Twelve elders first received new conventional CD, which were later converted to SIO. All variables were evaluated after use of each prosthesis for 2 months. To evaluate OSA, elders closed their eyes and orally identified test pieces prepared from raw carrots. A kinesiographic device was used to measure chewing movements during mastication of a test material (Optocal). Masticatory performance (MP) was determined with the sieving method, and a 3-day food diary verified nutrient intake based on a standard Brazilian Food Composition Table. Data were analyzed using the Wilcoxon signed rank test and Student’s paired t test (P < 0.05). OSA results did not differ according to prosthesis type. However, opening and closing velocities during chewing and MP increased after SIO insertion (P < 0.05). Although no difference was observed in the intake of most nutrients, sodium ingestion decreased after SIO insertion (P < 0.05). SIO use had no effect on OSA, but significantly improved mastication and sodium intake of elders with decreased residual ridges height (Brazilian Registry of Clinical Trials #RBR-3kgttj).

Effect of implant-supported mandibular overdentures versus reline on masticatory performance and salivary flow rates in very old adults-A randomized clinical trial

PURPOSE

To compare the masticatory efficiency (ME), maximum voluntary bite force (MBF), masseter muscle thickness (MMT), and salivary flow rates (SFR) in completely edentulous dependent elders treated either with a conversion of their existing mandibular complete removable dental prostheses (CRDPs) into a two-implant overdenture (IOD) or a conventional reline of the CRDP.

MATERIAL AND METHODS

Participants were randomly allocated into intervention (IG) and control (CG) groups. The IG received two implants in the mandibular canine regions, and their CRDPs were transformed into IODs. The CG received a conventional reline of their mandibular CRDPs. Outcomes were recorded at each recall visit (baseline, immediately, 3 months, 12 months after intervention, and subsequently on an annual basis). Statistical analyses used mixed linear regression models (level of significance: p < 0.05).

RESULTS

The IG comprised 16 participants (age = 85.0 ± 6.2 years), while the CG comprised 16 (age = 84.8 ± 5.4 years), with a mean follow-up of 2.7 ± 2.2 years (range: 3 months-7 years). A significant increase of MBF in the IG was observed with an overall gain of 80 N (p < 0.001) compared with the reline group. There were no significant long-term changes in SFR, MMT, or ME within/between groups.

CONCLUSION

Since dependent elders with mandibular IODs present a significant gain in MBF, but no relative increase in SFR, MMT, and ME, it seems that this increased capacity of MBF is not exploited by the elders during their habitual chewing.

Which variables should be controlled when measuring the granulometry of a chewed bolus? A systematic review

The distribution of food particles in a chewed bolus characterizes the food destruction after food oral processing (FOP). Previous reviews report that it could be affected by a lot of parameters as the number of chewing strokes, the dental status, but the conditions for producing reproducible data allowing inter-studies comparison have not been clearly described yet. This systematic review aims to identify the variables that can affect bolus granulometry determination, and to calculate their relative weights in the median particle size (D₅₀ ) variations. The systematic review focuses on granulometry expressed as D50 of the most used foods (peanuts, carrots, and almonds) and materials (Optosil and Optocal). Based on 58 studies, 5 variables among 60 being extracted could explain the D₅₀ variations. Conceptual differences between the conditions for FOP should be considered. After Chewing-test, the bolus is collected after a predefined number of strokes and its granulometry characterizes the effects of the dental and muscular apparatus on food destruction, while after Mastication-test the bolus is collected at the swallowing threshold, and its granulometry reflects the outcome of the abilities of the subject to adapt his/her mastication behavior to food texture. Experimental conditions related either to physical sieving or image analysis used to analyze the collected boluses impact the D₅₀ values. Finally, when type of test, sieving conditions, type of food or material, number of chewing strokes, and the oral status of the subjects are controlled, mean D₅₀ values are reproducible and could be used for inter-studies comparisons. PRACTICAL APPLICATIONS: This review provides tables that could be useful to control mean D₅₀ variations in further research.

The association between a mixing ability test and patient reported chewing ability in patients treated for oral malignancies

Introduction

Mastication has been assessed in several ways in the past. Both patients reported and objective assessment methods have been developed. The University Medical Center (UMC) Utrecht has developed a mixing ability test (MAT) using a two‐coloured wax tablet. The present study investigates the association between the mixing ability test and a chewing related questionnaire in patients treated for oral malignancies.

Patients and methods

In a cohort study, patients treated for oral malignancies were assessed 4‐6 weeks before and 4‐6 weeks after treatment, as well as 6 months, 1 year and 5 years after treatment. The mixing ability test was assessed using 10 and 20 chewing strokes and was compared to seven questions about several aspects of mastication. Regression analysis was performed and density plots were drawn for statistical analysis.

Results

One hundred and twenty‐three patients were included in this study. The questionnaire was less predictive for the 10‐chewing stroke test and the test was less discriminatory for different food types than the 20‐chewing stroke mixing ability test. Three questions about the ability to chew solid, soft and thickened liquid food types were found to be significantly predictive for the 20‐chewing stroke test. Threshold values on the mixing ability index were around 20 for the ability to chew solid food types and 24 for soft food types.

Conclusion

The 10‐chewing stroke mixing ability test is less suitable than 20‐chewing strokes for patients with and treated for oral cancer. The 20‐chewing stroke mixing ability test has a fair association with self‐reported outcomes.

Effect of ultraviolet photofunctionalization of dental titanium implants on osseointegration

OBJECTIVE

The aim of the current study was to evaluate the effect of ultraviolet (UV) photofunctionalization of dental titanium implants with exposure to the oral cavity on osseointegration in an animal model.

METHODS

Forty-eight titanium implants (Camlog^® Conelog^® 4.3 mmx9.0 mm) were placed epicrestally into the edentulous jaws of three minipigs and implant stability was assessed by measuring the implant stability quotient (ISQ). Prior to implantation half of the implants were photofunctionalized with intense UV-light. After three months, the implants were exposed and ISQ was measured again. After six months of implant exposure, the minipigs were sacrificed and the harvested specimens were analyzed using histomorphometric, light, and fluorescence microscopy.

MAIN RESULTS

Forty-two of 48 implants osseointegrated. The overall mean bone-implant contact area (BIC) was (64±22)%. No significant differences were found in BIC or ISQ value (multivariate analysis of variance (MANOVA), P>0.05) between implants with and without exposure to UV photofunctionalization.

CONCLUSIONS

No significant effects were observed on osseointegration of dental titanium implants nine months after exposure of UV photofunctionalization.

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.

Clinical performance of LOCATOR® attachments: A retrospective study with 1-8 years of follow-up

The use of LOCATOR® attachments in implant-supported removable dental prostheses (ISRDPs) has been evidenced with conflicting clinical behavior in literature. This retrospective study aimed to investigate the long-term clinical performance of LOCATOR® attachments by evaluating the frequency of the encountered mechanical complication events (MCEs) and the factors that play a role in attachment wear (AW). The study recruited participants with ISRDPs on LOCATOR® attachments. Clinical parameters, number of MCEs (attachment replacements, attachment loosenings, denture cap-related events, loss of retention and/or insert, and implant fractures), and AW were recorded. Nonparametric tests were applied for statistical analyses (𝛼=0.05). Baseline demographics for the recruited 47 participants (mean age: 72.0 ± 9.0 years) revealed an implant survival rate of 94.9% (mean observation period: 54.8 months), average peri-implant probing depths, bleeding on probing scores, and plaque scores of 1.80 ± 1.50 mm, 0.70 ± 0.90, and 0.81 ± 0.90, respectively. MCEs were directly influenced by the time in use (p < 0.001). The most frequently encountered MCEs were loss of retention (p < 0.001) and denture cap-related complications (p = 0.004). AW was found to be significantly higher in the maxilla than in the mandible (p = 0.028); in the maxilla, the vestibular (p = 0.005) and mesial (p = 0.01) aspects were the most common wear sites. Maxillary implant overdentures revealed more vestibular AW (p = 0.013). In prostheses supported by >3 implants, vestibular (p = 0.046) and mesial (p = 0.032) AW were common. Lingual AW (p = 0.021) was observed more frequently when the support was <3 implants. Loss of retention and AW are the most common complications encountered with LOCATOR® attachments. Therefore, a modification in the attachment design along with an amelioration of the attachment surface may help decrease the maintenance needs and further enhance its clinical performance.

Are UK graduates equipped with the skill set required to meet the demands of the UK's edentulous population?

As the UK witnesses a decline in the number of edentulous adults, there is a simultaneous reduction in the number of cases available to undergraduate dental students for the teaching of complete dentures. When edentulous adults are unable to function with conventional complete dentures, particularly pertaining to the mandibular denture, an implant-supported mandibular overdenture has been evidenced as the gold standard for edentulous patients. The evidence in favour of mandibular implant-supported overdentures is one of the most robust evidence bases for any clinical treatment and similarly it has been shown that undergraduate students are equally as capable in the provision of implant-supported overdentures as experienced prosthodontists. Yet there appears to be a disparity in the General Dental Council's undergraduate learning outcomes pertaining to care for edentulous adults. Furthermore, the UK seems to be falling behind in this respect in comparison to our European, American and Australian colleagues. This review looks at the evidence for the provision of implant-supported overdentures in the setting of the undergraduate dental curriculum, the potential barriers within this teaching forum and how well prepared UK undergraduates are for the clinical management of edentulous patients in the future.

Bar versus ball attachments for implant-supported overdentures in complete edentulism: A systematic review

BACKGROUND

Implant-supported overdenture is one of the most predictable treatment options used in complete edentulism. However, differences have been reported between bar and ball attachments used to retain overdentures in terms of patient satisfaction and prosthesis retention.

PURPOSE

The purpose of this study is to compare the effectiveness of bar and ball attachments for conventionally loaded implant-supported overdentures in completely edentulous patients to improve patient satisfaction and prosthesis retention.

MATERIALS AND METHODS

We conducted the review according to the Cochrane methods and following MECIR standards. We searched Cochrane Oral Health Group Trial register, Cochrane Central Register of Controlled Trials, MEDLINE, and the WHO ICTRP (March 31, 2017). Two review authors assessed trials for inclusion and risk of bias, extracted data, and checked for accuracy. We have expressed results as risk ratio or mean differences, together with their 95% confidence intervals.

RESULTS

We included 10 trials (465 participants). After 5 y, one trial reported higher patient satisfaction when bar attachment was used (MD 1.30, 95% CI 0.20-2.40), and reported no difference between both systems in prosthesis retention (MD -0.90, 95% CI -1.90 to 0.10). Two trials reported no implant failures after 1 and 5 y in both attachments. Downgrading of evidence was based on the unclear risk of bias of included studies and the wide CI crossing the line of no effect.

CONCLUSIONS

There is insufficient evidence to support bar or ball attachment to be used with implant-supported overdentures in completely edentulous patients to improve patient satisfaction and prosthesis retention (PROSPERO 2014:CRD42014014594).

Numerical investigation of complete mandibular dentures stabilized by conventional or mini implants in patient individual models

Poor stability of a complete denture is a common problem due to bone atrophy of the edentulous ridge. The aim of the present study was to analyze denture stability after receiving implants and to study the biomechanical properties of denture implants and the bone bed using conventional or mini implants. Five models based on computed tomography (CT) data of edentulous patients were created. The overdentures’ connection to the implants was assured by means of ball head abutments and rubber rings. In three models, the denture was supported by two to four conventional implants and in two models, the overdenture was supported by three to five mini implants. The dentures were loaded according to the individual biting forces which was clinically measured by means of pressure sheets. After implantation, the biting forces and displacements of overdentures increased in comparison to complete dentures. Displacements and stresses were higher with mini implants than with conventional ones. Stress in the implants was markedly below the yield stress of titanium grade 5 (880 MPa). An increase in the stress in the bone around the implants was noticed as compared to the situation with complete dentures which was below the physiological range of bone loading (<4 MPa).

How fast can treatment with overdentures improve the masticatory function and OHRQoL of atrophic edentulous patients? A 1-year longitudinal clinical study

OBJECTIVES

The aim of this prospective clinical study was to evaluate the masticatory function (MF) and subjective perception of patients with poor denture-bearing tissue in relation to change and the time required to identify an improvement in these parameters after rehabilitation with mandibular overdentures (MO) by two narrow-diameter two-piece implants.

MATERIAL AND METHODS

Twenty-three edentulous patients were selected for MO installation. The masticatory function (MF) was evaluated with the masticatory performance (MP) and swallowing threshold (ST) tests. In the MP test, each volunteer was instructed to masticate a portion of Optocal (standardized artificial test food) for 40 masticatory cycles. During the swallowing threshold test, the patients were instructed to chew a new portion of Optocal cubes until they felt the desire to swallow. The MF tests were performed while complete denture (CD) wearers (baseline) and 1, 3, 6, and 12 months after MO loading. In addition, the subjective perception was assessed through the questionnaires Dental Impact on Daily Living (DIDL), Geriatric Oral Health Assessment Index (GOHAI), and Oral Health Impact Profile in Edentulous (OHIP- EDENT) at the baseline and 3, 6, and 12 months after MO loading.

RESULTS

A significant improvement in masticatory function (p < .05) was observed already in the first month of loading. Three months after MO loading, a significant improvement (p < .05) was found in the subjective perception of patients. The effect size indicates that the MO had the greatest impact on the domains related to function and comfort of all questionnaires and in relation to psychosocial domain of the GOHAI. The level of patient satisfaction increased significantly after the MO loading and reached >90% satisfied patients at 12 months.

CONCLUSION

The MO improved both the MF of the patient and their oral health-related quality of life and satisfaction regarding the prosthesis in a short time period.

Masticatory muscle activity evaluation by electromyography in subjects with zygomatic implants

Background

Zygomatic implants are an alternative treatment in the rehabilitation of atrophic maxilla to promote stability in the stomatognathic system. The aim of this study was to compare the electromyographic (EMG) activity of masseter and temporalis muscles in controls and in individuals with complete implant-supported dentures anchored in the zygomatic bone.

Material and Methods

Fifty-four volunteers of both genders (mean age 52.5 years) were selected and distributed into two groups: Individuals with zygomatic implant (ZIG; n=27) and fully dentate patients (CG; n=27). MyoSystem-BR1 was used to assess masseter and temporalis muscles EMG activity in different mandibular movements: protrusion, clenching, maximal voluntary contraction (MVC) with Parafilm M®, right and left laterality and chewing (peanuts and raisins). Data was processed, normalized (MVC) and analyzed using the SPSS 21.0. Student t-test (P ≤ 0.05) was used for group comparison.

Results

The results were statistically significant (P ≤ 0.05) for protrusion, clenching, right and left laterality and raisin chewing. For the mandibular posture conditions, the ZIG obtained higher EMG activity patterns when compared to CG. For the masticatory performance during chewing of peanuts and raisins, the ZIG showed higher EMG mean values when compared to CG.

Conclusions

The zygomatic implant promoted an active response of the muscle fibers (hyperactivity) during both mandibular posture and chewing conditions, probably due to the absence of periodontal receptors, which play a significant role for preparing a bolus for swallowing.

Key words:Zygomatic implant, electromyography, masseter muscle, temporal muscle.