Implant-supported Overdentures Research Articles

There is no evidence that recommends a specific optimum number of implants for an overdenture

What is the optimal number of implants for removable reconstructions? A systematic review on implant-supported overdentures. Roccuzzo M, Bonino F, Gaudioso L, Zwahlen M, Meijer HJ. Clin Oral Implant Res 2012;23.s6:229-37. Systematic review with meta-analysis of data.

Changes in biting forces with implant-supported overdenture in the lower jaw: A comparison between conventional and mini implants in a pilot study

The biting ability of patients improves noticeably after receiving implant-supported overdentures in comparison to conventional complete dentures. However, the change of biting with such treatment concepts has been quantitatively investigated in only a limited number of studies. The aim of the present study has been to measure the biting forces of edentulous patients with complete dentures and after receiving implant-supported overdentures.A total of 26 edentulous patients were included. Ten patients received two to four conventional implants (control group, Ø3.3–3.7mm, L11–13mm) and 16 patients received four to five mini implants (study group, Ø1.8–2.4mm, L13–15mm) inserted in the mandibular interforaminal region. All patients received a lower overdenture with ball/rubber ring attachments and a complete denture for the maxilla. The biting forces were measured using Prescale pressure sheets type low before the insertion of implants and after receiving implant-supported overdenture. The measured sheets were later scanned and analysed using FPD-8010E software.The range of biting forces before the insertion of implants was 80N–122N for the control group and 66–88N for the study group. After the insertion of implants, the range of biting forces increased to 167N–235N for the control group and to 81N–138N for the study group. However, the increase in biting forces after the insertion of implants was not significant for either group. No significant difference was obtained between the two implant systems.The biting forces improved after insertion of implants regardless of which implant system was used. However, the degree of improvement is noticeably related to the original bone quality of the mandible at the insertion regions of implants.

Effect of cantilever length on stress distribution around implants in mandibular overdentures supported by two and three implants.

Objective:There is no definitive study comparing stress distribution around two versus three implants in implant-retained overdentures with different cantilever length. The purpose of this finite element study was to evaluate stress pattern around the implants of the 2 or 3 implant- supported mandibular overdenture with different cantilevered length.Materials and Methods:The models used in this study were 2 and 3 implant-supported overdenture with bar and clip attachment system on an edentulous mandibular arch. Each model was modified according to cantilever length (0 mm, 7 mm, and 13 mm); thus, 6 models were obtained. The vertical load of 15 and 30 pounds were applied unilaterally to the first molar and 15 pounds to the first premolar, and the stress in bone was analyzed.Results:With increasing cantilever length, no similar stress pattern changes were observed in different areas, but in most instances, an increase in cantilever length did not increase the stress around the implant adjacent to cantilever.Conclusions:Within the limitations of this study, it can be concluded that increasing of cantilever length in mandibular overdentures retained by 2–3 implants did not cause distinct increasing in stress, especially around the implant adjacent to cantilever, it may be helpful to use cantilever in cases of mandibular overdenture supported by splinted implants with insufficient retention and stability. Based on the findings of this study, optimal cantilever length in mandibular overdenture cannot be determined.

Oral Rehabilitation with Implant-Supported Overdenture and a New Protocol for Bar Passivation

Every prosthetic rehabilitation aims to restore the stomatognathic apparatus and to achieve a satisfactory aesthetic, harmonized with the patient's face and able to support lips and cheeks after the loss of teeth and alveolar bone. In this situation, the choice of the type of prosthesis (fixed or removable) and its creation acquire great importance. In this case a 56 years old patient suffering from aggressive periodontitis was treated by placing 3 implants into the upper jaw to support an overdenture and 4 implants into the lower jaw to support a fixed titanium-composite prosthesis. The upper bar was passivated using the Elastic Seeger system with its acetalic rings, which are able to compensate the blank space between the bar and the Equator abutments creating, thereby, a monoblock with warranty of absolute passivation. The protocol followed in the present study with the use of low-profile attachments in OT Equator and the Elastic Seeger system simplified the procedures of dental clinics and reduced the working time. The study also underlined the importance of musculoskeletal analysis when the right prosthetic rehabilitation had to be chosen.

One-year results of maxillary overdentures supported by 2 titanium-zirconium implants - implant survival rates and radiographic outcomes.

To assess implant survival rates and peri-implant bone loss of 2 titanium-zirconium implants supporting maxillary overdentures at 1year of loading. Twenty maxillary edentulous patients (5 women and 15 men) being dissatisfied with their complete dentures were included. In total, 40 diameter-reduced titanium-zirconium implants were placed in the anterior maxilla. Local guided bone regeneration (GBR) was allowed if the treatment did not compromise implant stability. Following 3 to 5months of healing, implant-supported overdentures were inserted on two ball anchors. Implants and overdentures were assessed at 1, 2, 4, and 8weeks after implant insertion and 2, 4, and 12months after insertion of overdentures (baseline). Standardized radiographs were taken at implant loading and 1year. Implant survival rates and bone loss were the primary outcomes. Nineteen patients (1 dropout) with 38 implants were evaluated at a mean follow-up of 1.1years (range 1.0-1.7years). One implant failed resulting in an implant survival rate of 97.3%. There was a significant peri-implant bone loss of the implants at 1year of function (mean, 0.7mm, SD = 1.1mm; median: 0.48mm, IQR = 0.56mm). There was a high 1-year implant survival rate for edentulous patients receiving 2 maxillary implants and ball anchors as overdenture support. However, several implants exhibited an increased amount of bone loss of more than 2mm. Overdentures supported by 2 maxillary implants should thus be used with caution as minimally invasive treatment for specific patients encountering problems with their upper dentures until more long-term data is available.

Implant supported dental rehabilitation following segmental mandibular reconstruction- quality of life outcomes of a prospective randomized trial

The primary objective of this study was to assess the difference in quality of life (QoL) in patients with dental rehabilitation using two or four implant-supported overdentures following segmental mandibulectomy defect reconstruction with fibula free flap. This prospective, parallel designed, randomized clinical study was conducted with a 1:1 ratio. At baseline, all participants already had fibula flap reconstruction for segmental defects of the mandible and rehabilitation with conventional (non-implant supported) removable partial dentures. The participants were then randomized into two groups. Group I received implant supported overdentures on two implants, and Group II received four implants. QoL outcomes were evaluated using standardized questionnaires (EORTC_QLQ c30, H&N35, OHIP, DSI). Outcomes of treatment were evaluated at 6 months (T1) and 1 year (T2) following rehabilitation. A total of 52 patients were randomized into two treatment groups (26 each). After accounting for the loss to lack of follow-up, 22 patients in Group I and 24 patients in Group II were evaluated for QoL at the end of the study. There was a significant improvement in QoL with implant-assisted dental rehabilitation. However there were no significant differences in QoL between the two-implant and four-implant groups. Implant-supported removable overdentures improve QoL outcomes in patients with reconstructed mandibles. This study showed no significant difference in QoL outcomes in patients with two- or four-implant supported removable prostheses.

COMPARATIVE STUDY BETWEEN TWO TYPES OF ATTACHMENTS USED FOR ROOT-SUPPORTED OVERDENTURE

INTRODUCTION: The incorporation of attachments in overdentures into everyday dental practice will open up another dimension in dental treatment planning and patient satisfaction. Teeth that might be considered for extraction may be considered as long or short term alternatives to implant or total edentulousness. Some teeth are maintained to support and/or retain the prosthesis and therefore, maximizing prosthesis stability, besides preserving proprioception of the periodontal ligament and reducing bone loss. Tooth-supported overdentures can be retained with attachments and can improve both retention and stability while simultaneously reducing alveolar bone resorption. They may also be more cost-effective and maintain more dental proprioception than implant-supported overdentures. OBJECTIVES: To compare clinically and radiographically between flex pivot (precision attachment with flexible male sphere) and castable pivot (semiprecision attachment) used for root-supported overdenture.MATERIALS AND METHOD: This randomized parallel controlled clinical study was conducted on twelve patients having bilateral mandibular single rooted teeth; canines or first premolars. Those were divided into two groups of six subjects. Group A (study group) each of six patients received flex pivots (precision attachment with flexible male sphere) bilaterally as test group. Group B (control group) six patients received castable pivots (semiprecision attachment) bilaterally as control group.RESULTS: When the data of changes in the clinical and radiographic parameters of periodontal status over a 6 months period were compared at immediate post-treatment, 1, 3, and 6 months intervals relative to type of attachment, the findings revealed there were no significant differences among precision attachment group in most of the mean values, while the opposite was shown in semiprecision attachment.CONCLUSIONS: Precision attachment with flex pivot was associated with more superior clinical periodontal parameters than precision attachment, and it is more biocompatible, hygienic, and maintaining healthy, stable periodontal soft tissue and crestal alveolar bone level.

Biting Force and Muscle Activity in Implant-Supported Single Mandibular Overdentures Opposing Fixed Maxillary Dentition.

This study aimed to investigate the relation between biting force and masticatory muscle activity in patients treated by 3 modalities of single mandibular dentures. Forty implants were placed in 10 patients with completely edentulous mandibles. The study was divided into 3 treatment stages. Initially, each patient received a conventional mandibular complete denture. At the second stage, 4 mandibular implants were placed and the denture was refitted to their abutments. Third stage comprised connecting the denture to the implants through ball attachments. During each treatment stage, maximum biting force and muscle activity were measured during maximum clenching and chewing of soft and hard food. Biting force demonstrated a statistically significant increase by time for the 3 treatment stages. The highest muscle activity was recorded for the conventional denture followed by the implant-supported overdenture without attachment, whereas the lowest values were recorded for the implant-supported overdenture with attachment. Biting force was related mainly to the quality of denture support. Muscle activity was higher in patients with conventional denture than with implant-supported prostheses (with or without attachments).

Use of ceria-stabilized zirconia/alumina nanocomposite for fabricating the frameworks of removable dental prostheses: A clinical report

Ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) exhibits an elasticity equivalent to that of cobalt–chromium alloy and a flexural property that is superior to that of yttria-tetragonal zirconia polycrystal. Therefore, the use of Ce-TZP/A for the fabrication of removable dental prosthesis frameworks is being studied. However, the current English literature does not include any clinical report on the use of Ce-TZP/A for the fabrication of the entire framework. This clinical report describes the process and outcomes of fabricating a mandibular implant-supported overdenture and a maxillary complete denture with Ce-TZP/A as the framework material.

Remodeling of the Mandibular Bone Induced by Overdentures Supported by Different Numbers of Implants.

The objective of this study was to investigate the process of mandibular bone remodeling induced by implant-supported overdentures. computed tomography (CT) images were collected from edentulous patients to reconstruct the geometry of the mandibular bone and overdentures supported by implants. Based on the theory of strain energy density (SED), bone remodeling models were established using the user material subroutine (UMAT) in abaqus. The stress distribution in the mandible and bone density change was investigated to determine the effect of implant number on the remodeling of the mandibular bone. The results indicated that the areas where high Mises stress values were observed were mainly situated around the implants. The stress was concentrated in the distal neck region of the distal-most implants. With an increased number of implants, the biting force applied on the dentures was almost all taken up by implants. The stress and bone density in peri-implant bone increased. When the stress reached the threshold of remodeling, the bone density began to decrease. In the posterior mandible area, the stress was well distributed but increased with decreased implant numbers. Changes in bone density were not observed in this area. The computational results were consistent with the clinical data. The results demonstrate that the risk of bone resorption around the distal-most implants increases with increased numbers of implants and that the occlusal force applied to overdentures should be adjusted to be distributed more in the distal areas of the mandible.

Patient-reported outcome and its association with attachment type and bone volume in mandibular implant overdenture.

To determine oral health-related quality of life (OHRQoL) and denture satisfaction (DS) in patients provided with mandibular implant-supported overdentures (ISOD) retained by two different attachment types, and the association of mandibular bone volume with the change in patient-reported outcome, before and after implant treatment. Thirty-four patients (mean age 60.70 ± 8.7years) received telescopic crown or locator attachments for ISOD and completed OHIP-14 (Malaysian version) and DS questionnaires, at baseline (T0 ) with new conventional complete dentures (CCD) and 3months (T1 ) and 3years (T2 ) after ISOD conversion. Mandibular bone volume was calculated from cone beam computed tomography (CBCT) datasets using Mimics software. Mean changes (MC) in OHIP-14 and DS at intervals were analyzed using the Wilcoxon signed-rank test and effect size (ES). The association of bone volume, implant attachment type, and other patient variables with the change in OHIP-14 and DS were determined using multivariate linear regression analysis. The MC in OHIP-14 and DS scores from T0 to T1 and T2 showed significant improvement with moderate and large ES, respectively. Regression analyses for the change in OHIP-14 score from T0 to T2 showed significant association with implant attachment type (P=0.043), bone volume (P=0.004), and baseline OHIP-14 (P=0.001), while for DS, the association was only significant with baseline DS score (P=0.001). Improvement in patients' OHRQoL and satisfaction with ISOD was associated with their baseline ratings. Mandibular bone volume had a stronger association for improvement in OHRQoL compared to type of attachment.

Evaluation of Satisfaction Level in Patients With Mandibular Implant Supported Overdentures

Background: Implant-supported overdentures could have many benefits for patients, especially in the lower jaws. As a matter of fact, the most common reason for prescribing mandibular overdenture is dissatisfaction of patients with mandibular dentures usually because of a lack of retention, stability and function and speech difficulties. On the other hand, patients' expectations of overdenture treatments are their main disadvantage. Objectives: The aim of this study was to evaluate the satisfaction of patients who had received mandibular implant supported overdenture treatment with different number of implants. Patients and Methods: This study was a descriptive cross-sectional study. Twenty-five patients with a mean age of 62.7 years who had received mandibular implant supported overdenture treatment at the dental school of Hamadan University of Medical Sciences were enrolled. Among these patients, six had overdentures supported by one implant, nine had overdentures supported by two implants, two had overdentures supported by three implants, five had overdentures supported by four implants and three had overdentures supported by five implants. The visual analogue scale (VAS) questionnaire was used to evaluate the general satisfaction, comfort, esthetic, fitness, satisfaction of chewing and social communication, and the data was analyzed by the analysis of variance (ANOVA) test. Results: All patients in all five groups were satisfied with their overdentures; however there was no significant relationship between the number of implants and fitness (P = 0.446), esthetic (P = 0.843), comfort (P = 0.805), satisfaction of chewing (P = 0.133), social communication (P = 0.322) and general satisfaction (P = 0.493). Conclusions: There was no difference in satisfaction level of patients who had received mandibular overdentures with different number of implants.

Using overdenture on implants and complete dentures: Using overdenture on implants and complete dentures: Using overdenture on implants and complete dentures: effects on postural maintenance of masticatory effects on postural maintenance of masticatory musculature musculature

Aims: Thanks to advances in osseointegration, oral rehabilitation specialists have had the option of using implants to improve retention and stability in treatments with complete dentures. This study compared the masticatory muscle electromyographic activity in implant-supported overdenture wearers, complete denture wearers and dentate individuals. The electromyographic activity of the right and left masseter muscles, and the right and left anterior temporalis muscles was analyzed in 10 implant-supported overdenture wearers (Group 1), 10 conventional complete denture wearers (Group 2), and 10 dentate individuals (Group 3), with mean age of 65 years, at rest and during postural position maintenance. The analysis was performed using the MyoSystem-Br1 electromyographer with differential active electrodes. Analysis of variance tests were carried out to compare the groups and muscles and revealed different electromyographic values that were statistically significant at 1% significance level. Duncan’s pos-hoc test showed that Group 3 presented the smallest values (pd”0.01). The electromyographic contraction pattern was similar between Groups 1 and 3 (p>0.01), and hyperactivity of anterior temporalis muscles was observed in Group 2 (pd”0.01). Conclusions: dentate individuals had smaller electromyographic values of masticatory muscles and the overdenture use caused electromyographic contraction patterns similar to those of dentate individuals in both positions.

Teaching mandibular implant-Supported overdentures in dental schools in North America - a survey.

Mandibular two-implant overdentures are considered the minimum standard of care for edentulous patients and provide an excellent performance, as well as satisfaction to the patients. Dental schools are required to promote the teaching of current treatment options in order to enable students to master state-of-the-art procedures. The purpose of this study was to examine how the theoretical and practical aspects of mandibular two-implant overdentures are taught in dental schools in North America. Data were collected via an online questionnaire that included questions regarding the theoretical and clinical courses, surgical procedure and imaging method. Of 75 schools, 36 responded to the survey. Almost all the schools teach the subject theoretically, but it is not mandatory for students to perform in most of the schools. Only a minority (23%) of the mandibular dentures made by students are implant-supported. Almost all of the schools (94%) use two implants to support overdentures, and Locator abutment is used almost exclusively. The prevalent imaging for the surgical procedure is CT scans, although 30% of the schools use panoramic radiograph. None of the schools loads the implants immediately after surgery. Some clear trends are apparent in the current survey: the use of two implants, no use of bar connectors and delayed loading of the implants. It is likely that graduates will not have sufficient clinical skills and will need continuing education to be familiar with the required procedures, both surgical and prosthetic.

Success rate in implant-supported overdenture and implant-supported fixed denture in cleft lip and palate patients.

Background:The prosthetic treatment in cleft patients is challenging. Based on this, the aim of this study was to evaluate the longevity of prosthetic rehabilitation treatment with implant-supported overdenture (IOD) and implant-supported fixed denture (IFD) in cleft lip and palate patients in a period of 22 years.Materials and Methods:The medical records of 72 patients were analyzed (29 males and 43 females), and the survival rate of the implants was evaluated. Moreover, the prostheses’ time of use and the reason for the changing of these were also evaluated.Results:Four-hundred-seventeen implants were installed, and 370 implants survive today. The mean survival time of the implants was 7.6 years. Regarding the 97 prostheses made, the time of average use was 3.28 for the IFDs and 3.92 for IODs. The reasons for the replacements of the prostheses were mainly: fracture of the acrylic base (29.6%) and loss of vertical dimension of occlusion (VDO) (18.5%) in the IFDs. Moreover, in IODs, these were accounted for the loss of VDO due to teeth damage (17.2%) and implant loss (14.6%).Conclusions:The maintenance of the prostheses was challenging because the patients had difficulties returning for periodic control, but this fact did not result in the decrease of the success rate of the implants. The longevity of implants and prostheses was satisfactory; however, the prostheses showed repetitions mainly due to the wear of the teeth, with decreased vertical dimension and fracture of acrylic base.

Clinical and radiographic evaluation of implant-supported removable partial overdenture in the lower Kennedy class IV cases

Introduction The objective of the present study was to evaluate the effect of implant-supported partial overdenture design in restoring mandibular long class IV Kennedy's classification on the supporting structure, both clinically and radiographically. Materials and methods Ten partially edentulous patients with lower six anterior teeth missing were selected. Their ages ranged from 40 to 50 years. Each patient received two dental implants placed in the lower edentulous span at the canine area bilaterally. Ball-and-socket attachment (polycarbonate housing with rubber O-ring) was used between the implant and the overlay removable partial denture for retention. Periodic evaluation was carried out for every patient before denture insertion and then after 3, 6, and 9 months. As regards the clinical evaluation, the probing depth, gingival level, and attachment level around the implants were recorded. The radiographic evaluation included the use of specially developed software for measuring the alveolar bone density in gray scales and the bone height in pixels for the implants and the residual alveolar ridges. Results All implants were highly successfully osseointegrated at the end of this study. There was a statistically nonsignificant increase in the clinical parameters (probing depth, gingival level, and attachment level) around the dental implants throughout the 9-month follow-up period after denture insertion. Radiographically, there was a nonsignificant increase in bone loss, but a significant increase in bone density around the dental implants and the alveolar ridge throughout the follow-up period. Conclusion From the previous results, it was found that the concept of immediate loaded dental implant was efficient to be used successfully in the mandibular long Kennedy class IV to retain the partial overdenture.

The impact on bone tissues of immediate implant-supported mandibular overdentures with cusped and cuspless teeth

Objectives:To examine the effects on bone tissues of immediate implant-supported mandibular overdentures with cusped or cuspless teeth.Methods:A randomized controlled trial was conducted at the Dental Clinic, Faculty of Dentistry, Al-Azhar University, Assiut Branch, Egypt, over a 12-month period from September 2013 to September 2014. Twenty patients were treated with immediate implant-supported overdentures: one group received overdentures with cusped teeth, and the other group received overdentures with cuspless teeth. The rate of implant success was assessed clinically and radiographically at 3, 6, 9, and 12 months. The data were collected by a questionnaire, an observation checklist, and radiography. The data were then analyzed using computerized methods.Results:Overdentures with cusped teeth showed a significant improvement in the clinical criteria, including the absence of clinical implant mobility, pain, and bone resorption, while the clinical criteria for the absence of peri-implant radiolucency were insignificantly different between the 2 groups (p>0.05). There were no significant differences in the clinical evaluations for bone levels at the time of insertion or 3 months after insertions, while significant differences were found at 6, 9, and 12 months after insertion.Conclusion:Overdentures with cusped teeth supported by immediate implants were found superior regarding many clinical criteria than those cuspless counterparts.

Rehabilitation of edentulous maxilla with implant-supported milled bar overdenture using CAD/CAM customized abutment: A case report

In patients with fully edentulous maxilla, fabrication of implant-supported overdenture can be a viable treatment option, when a minimum of six implants were strategically placed. Among several attachment systems used for implant-supported overdentures, milled-bars prevent rotational movement of denture, thus showing great stability, and have the advantage of splinting multiple implants with each other. In this case report, a milled-bar supported overdenture was fabricated for a patient suffering from condition of fully edentulous maxilla with severe ridge resorption in the anterior residual ridge. Seven implants composed of three different systems were effectively utilized by CAD/CAM customized abutment and cement-retained milled bar. (J Korean Acad Prosthodont 2016;54:146-51)

Evaluation of patient satisfaction and masticatory performance between complete dentures and single implant-supported overdentures with locator and ball attachments

Aim: This study was conducted to evaluate the impact of two different attachment systems on a single implant-retained mandibular overdenture on the oral health-related quality of life of completely edentulous individuals. Materials and Methods: Twelve completely edentulous, first-time denture wearer patients were selected for the study. A set of new conventional complete dentures was fabricated for each patient. Each patient received a single mandibular symphyseal implant which was conventionally loaded with a ball or locator attachment using the cross-over study design. The Oral Health Impact Profile-49 questionnaire and sieve method were used to assess the masticatory performances at various intervals. Results: The paired samples test was used to evaluate the correlation between conventional complete dentures and implant-supported overdentures (ISOD) and the attachments within each group. The independent paired samples test was used to evaluate the correlation between each of the attachments. The results of this study were in favor of the ball attachment at the end of the 2-month period. Conclusion: Within the limitations of this short-term cross-over trial, it may be concluded that single implant-supported mandibular overdentures and a connecting ball attachment are a viable treatment option for the edentulous population with problematic mandibular dentures.

補綴学的空間に配慮してインプラントオーバーデンチャーを再製した一例

補綴学的空間に配慮してインプラントオーバーデンチャーを再製した一例