Single Implant-retained Mandibular Overdentures Research Articles

A Prospective Study of Immediately Loaded Single Implant-Retained Mandibular Overdentures: Long-Term Results with 15-Year Follow-up.

To investigate the long-term predictability of simplifying mandibular overdenture treatment using single-stage surgery and immediate prosthetic loading of a single implant to provide a more affordable treatment option. A total of 29 patients with a mean age of 68 years with problematic mandibular dentures were treated. A single implant (Brånemark System Mklll TiUnite, Nobel Biocare) was placed into the mandibular midline for primary stability. A ball attachment was placed, and the retentive cap was incorporated into the existing denture. The patients were recalled at 3 and 12 months and at 3, 5, 10, and 15 years. Clinical assessments, radiographs, and resonance frequency analysis were recorded. All complications, failures, maintenance, and reasons for failure to follow-up were noted. Visual analog scale (VAS) questionnaires were used to record patient satisfaction (ANOVA; P < .05). One implant did not achieve sufficient primary stability to be immediately loaded and was treated with a two-stage delayed loading protocol. Of the 28 patients receiving immediately loaded implants, 14 patients were available for follow-up at 15 years. Implant survival remained at 100% throughout the study. Patient satisfaction was high, with a significant increase in all comfort and functional parameters (P values ranged from < .001 to .07) throughout the 15-year period. These 15-year results indicate that immediate loading of a single oxidized surface implant used to retain a mucosa-borne overdenture is a safe, reliable, and cost-effective treatment with high levels of patient satisfaction long term.

Comparison of Man Hours Utilized for Mandibluar Overdenture Treatment Retained by Single Implant with Bar Fabricated by CAD-CAM Process and Conventional Casting Processs – An Vivo Study

ABSTRACT Introduction: Both the population’s average life expectancy and the number of patients without teeth are rising. A 2012 epidemiological survey in India found that 30% of the population is edentulous. The rehabilitation process with a set of removable maxillary and mandibular complete dentures is the standard treatment for patients who are edentulous. This study is the first to incorporate and compare a novel approach to a single implant-retained mandibular overdenture with a bar attachment fabricated by CAD-CAM and a casting process on a single implant in the symphysis region. Method: Five maxillary and mandibular completely edentulous patients were enrolled in the study. Results: Significant difference was seen in the conventional laboratory time and CAD-CAM time as P &lt; 0.05 Conclusion: Compared to the conventional casting process, the single implant-supported bar mandibular overdenture (SISBOD) with a novel bar required fewer man hours and was more convenient.

Single Implant-Retained Mandibular Overdentures: A Literature Review.

The absence of teeth, known as edentulism, poses considerable obstacles in prosthodontic care and greatly affects a person's well-being. Conventional complete dentures frequently lead to problems like instability and insufficient retention, especially in the lower jaw. Fortunately, the introduction of dental implants has transformed the way we approach edentulous patients, as they now offer support and enhanced retention for removable prostheses, thus revolutionizing their treatment. While a consensus exists on using two implants for retaining mandibular overdentures, the associated cost may be prohibitive for economically disadvantaged individuals. As a solution, the concept of single implant-retained mandibular overdentures has emerged, catering to individuals with limited financial resources and complete tooth loss. This review explores the efficacy and suitability of the single implant overdenture approach, along with an overview of treatment options for edentulous patients, including traditional dentures, tooth-supported overdentures, and implant-supported overdentures. The preservation of bone, improvements in functional abilities, and psychological benefits associated with overdentures are discussed. Moreover, various classifications and prosthetic options for implant overdentures, specifically for mandibular cases, are presented. This literature review aims to provide a comprehensive understanding of possible treatment options and focus on the single implant-retained mandibular overdenture approach and its implications in prosthodontic rehabilitation for edentulous patients.

Comparative evaluation of masticatory efficiency, clinical performance, and patient satisfaction of single implant-retained mandibular overdenture versus conventional complete denture: A prospective in vivo study.

The aim of this within-subject prospective clinical study was to investigate the scope of single implant mandibular overdenture by assessing its masticatory efficiency, clinical performance, and patient satisfaction compared to conventional complete dentures. Prospective In Vivo Study. This prospective in vivo study was conducted in the Department of Prosthodontics and Crown and Bridge, Christian Dental College, Ludhiana. A total of 12 completely edentulous patients received a single implant in the mandibular anterior midline region. After the healing period, the conventional maxillary and mandibular dentures were fabricated. 15 days post insertion of the conventional dentures, patients were evaluated for masticatory efficiency, clinical performance including retention and stability, and patient satisfaction. To evaluate the masticatory efficiency blue raspberry and original pink "Hubba Bubba tape gum" were used as a test food. Colorimetric analysis was done to assess variance of hue. To assess clinical performance, retention, and stability of the mandibular denture was recorded using a digital force gauge and was tabulated as per CU-modified Kapur's criteria. OHIP-14 index was used to assess patient satisfaction. After evaluation of the parameters of conventional dentures, the denture was converted into an implant-retained mandibular denture by chairside conversion with locator attachments. 15 days post-implant loading, parameters of the implant retained mandibular overdenture were assessed again followed by statistical analysis. The masticatory efficiency was assessed using a paired t-test. The patient satisfaction was sequentially assessed with Wilcoxon signed rank test and thereafter paired t-test was used to compare between conventional complete denture and overdenture. Clinical performance was assessed using the Wilcoxon signed rank test. The masticatory efficiency of single implant mandibular overdenture was higher than that of conventional complete dentures. The clinical performance of the overdenture was higher than that of the conventional denture. Stability being a time-dependent parameter might need longer follow-ups for further conclusions. Patient satisfaction with single implant retained overdenture was significantly higher than conventional complete dentures. Single implant mandibular overdenture has improved masticatory efficiency, clinical performance, and patient satisfaction compared to conventional complete dentures.

Comparison of the Quality of Life Among the Immediate Loading Implant Overdentures Using the Single and the Double Implants: An Original Study.

In edentulous individuals, single implant-retained mandibular overdentures are an effective substitute for double implant-retained overdentures. In this current research, the oral health-related quality of life (OHRQoL) was assessed for the immediate loading overdenture using the implants. The comparisons are drawn between the single and double implants. Forty subjects received single and double implants for the placement of the mandibular overdentures. Within a week days of implant insertion, they were loaded with overdentures. Using the Oral Health Impact Profile-14 (OHIP-14) questionnaire, the OHRQoL was measured before treatment, one month following treatment, and 12 months thereafter. In both the single implant and double implant groups, participants' mean OHIP-14 scores decreased statistically significantly for the different timelines. For the single implant group, the baseline total mean OHIP-14 score was 14.33, and for double implants, it was 19.15. Following therapy, it decreased to 8.55 in the single implant group and 9.48 for the double implant group at one month, and at 12 months, it further decreased to 3.25 in the single implant group while it was 5.15 in the double implant group. Single and double implants increase the QoL for older subjects who are edentulous at the 1-month and 1-year recall points. When two implants are used by older individuals, the single implant might offer an equivalent quality of life.

Evaluation of patient satisfaction and masticatory efficiency of single implant-retained mandibular overdenture using two types of matrices.

Evaluation of patient satisfaction and masticatory efficiency of single implant-retained mandibular overdenture using two types of matrices.

A randomized controlled trial of ball and socket vs O-ring attachments for single implant-retained mandibular overdentures. A study of crestal bone loss and patient satisfaction

Purpose: This short term randomized controlled trial aimed to evaluate crestal bone loss and patient satisfaction of ball and socket and O-ring attachments used to retain single implant-retained mandibular overdenture after one year. Materials and methods: Twelve completely edentulous patients received single implant in the midline of the mandible. Three months later, the patients were randomly assigned into two groups; Group 1 (control group); six patients their mandibular dentures were connected to the implant using ball and socket attachment. Group 2 (test group); included six patients their mandibular dentures were connected to the implant using O/ring attachment. The peri-implant crestal bone loss was evaluated at mesial, distal, buccal and lingual aspects of each implant using cone beam computerized tomography made at baseline, 6 and 12 months later. Patient satisfaction was evaluated using questionnaire of visual Analogue Scales (VAS) six months after loading. Results: The implant survival rate was 100% in both groups. Ball and socket attachment recorded significant higher crestal bone loss than O-ring attachment after 6 months (p=.031) and 12 months (p=.021). Ball and socket attachment recorded significant higher patient satisfaction than O/ring attachment. Conclusion: O/ring attachment is recommended than ball and socket attachment for single implant mandibular overdentures in term of peri-implant bone preservation. However, ball and socket attachment was associated with significant higher patient satisfaction than O/ring attachment.

Masticatory efficiency in complete denture and single implant-retained mandibular overdenture wearers with different occlusion schemes: A randomized clinical trial

Statement of problemHow the masticatory function of complete denture wearers is influenced by the positioning and occlusion of posterior teeth or by the presence of a single mandibular implant is unclear. PurposeThe purpose of this randomized crossover clinical trial was to evaluate the masticatory efficiency of wearers of bimaxillary complete dentures and of wearers of maxillary complete denture and single implant-retained mandibular overdentures, both with bilateral balanced occlusion and lingualized occlusion. Material and methodsParticipants received 2 sets of complete dentures with interchangeable teeth in the mandibular prosthesis to allow a change in the occlusion scheme. Subsequently, 1 implant was placed in the mandibular symphysis region, and the mandibular complete dentures were converted to overdentures. The masticatory efficiency was measured by the sieve method for both occlusal schemes. ResultsRepeated measures ANOVA showed no statistically significant difference in the masticatory efficiency with the 2 occlusal schemes for conventional complete dentures (P=.707) or overdentures (P=.407). When comparing the type of prosthesis, statistical differences were found for masticatory efficiency (P=.012), with improved mastication for the overdentures. ConclusionsA mandibular single implant improved the masticatory efficiency of patients with complete dentures, but the occlusal scheme did not influence this factor.

Change in Bite Force of Completely Edentulous Patients After Placement of Single Implant-Retained Mandibular Overdentures

Purpose: This study aimed to assess the change in the maximum bite force of completely edentulous patients rehabilitated with thermoplastic acrylic complete denture after placement of single implant-retained mandibular overdentures. Materials and Methods: Sixteen completely edentulous patients with age ranged from 50-60 years were selected from removable prosthodontic clinics, faculty of dental medicine, Al-Azhar University. Each patient received a thermoplastic acrylic complete denture. Three months after a new denture placement, bite force was evaluated using an occlusal force meter (GM10, Nagano Keiki, Japan). Each patient received a mid-symphyseal single dental implant, 10 mm length and 3.7mm diameter (Dentis, Dalseo-gu, Daegu , Korea) placed at the midline of the mandibular alveolar ridge. Two weeks after overdenture placement, bite force was evaluated to assess the changes in bite force after a single implant placement. Results: Bite force was increased considerably after single implant placement. It was significantly higher than the bite force recorded with a conventional thermoplastic complete denture. Conclusion: It was concluded that using immediate loading single implant-retained mandibular overdentures resulted in considerable improvement of bite force in completely edentulous patients.

Retracted: "Crestal Bone Changes and Patient Satisfaction with Single Implant-Retained Mandibular Overdentures with Dalla Bona and Locator Attachments with Immediate Loading Protocols. A Randomized Controlled Clinical Study." by Nischal etal.

Journal of ProsthodonticsVolume 30, Issue 5 p. 462-462 RETRACTIONFree Access Retracted: “Crestal Bone Changes and Patient Satisfaction with Single Implant-Retained Mandibular Overdentures with Dalla Bona and Locator Attachments with Immediate Loading Protocols. A Randomized Controlled Clinical Study.” by Nischal et al. This article retracts the following: Crestal Bone Changes and Patient Satisfaction with Single Implant-Retained Mandibular Overdentures with Dalla Bona and Locator Attachments with Immediate Loading Protocols. A Randomized Controlled Clinical Study Kunal Nischal MDS, Sunil Kumar Mishra MDS, Ramesh Chowdhary MDS, PhD, Volume 29Issue 9Journal of Prosthodontics pages: 756-765 First Published online: August 26, 2020 First published: 07 June 2021 https://doi.org/10.1111/jopr.13357AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat The above article, published online on August 2, 2020 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal's Editor in Chief, Dr. Radi Masri, the American College of Prosthodontists, and Wiley Periodicals LLC. The retraction has been agreed due to evidence of image manipulation in Figures 1 and 2. Upon further analysis by image experts, it was determined that there was duplication between Figures 1 and 2, as well as possible background modification in Figure 2. The authors have indicated that these errors were unintentional and have agreed to retract. Reference 1Nischal, K., Mishra, S.K. and Chowdhary, R. (2020), Crestal Bone Changes and Patient Satisfaction with Single Implant-Retained Mandibular Overdentures with Dalla Bona and Locator Attachments with Immediate Loading Protocols. A Randomized Controlled Clinical Study. Journal of Prosthodontics, 29: 756– 765 https://doi.org/10.1111/jopr.13230Wiley Online LibraryPubMedWeb of Science®Google Scholar Volume30, Issue5June 2021Pages 462-462 ReferencesRelatedInformation

Evaluation of masticatory muscle activity and survival rate of single implant-retained mandibular overdenture fabricated from thermoplastic versus conventional acrylic resin. A randomized controlled trial

Background: Electromyographic (EMG) activities of single implant-retained mandibular overdentures (MODs) has been dubious. Midline fracture of the denture is the most common complication related to Single implant-retained MODs. Thermoplastic polymethylmethacrylate (PMMA) acrylic resin achieves even distribution of forces and helps in absorption of impact forces which occurs during functional and parafunctional activities. Aim of the study: This clinical study aimed to investigate whether thermoplastic PMMA can improve the EMG activity and decrease the incidence of denture fracture in single implant- retained MODs. Materials and Methods: A randomized controlled trial was designed, where 28 completely edentulous patients (15 male, 13 female) were enrolled and randomly divided into two equal groups. Group I (control group) received single implant- retained MOD fabricated from conventional PMMA and group II received a single implant- retained MOD fabricated from thermoplastic PMMA acrylic resin. Patients’ muscle activity was evaluated at baseline and at 3, 6 and 12 months using EMG. The survival rate of MOD was evaluated by recording the incidence of mid-line fractures. Results: There was a significant improvement in the EMG activity of the masseter and temporalis muscle of the thermoplastic PMMA group in all the follow-up periods. There was a non-statistically significant difference in the MOD survival between groups. However, the decrease in fracture incidence was clinically significant in the thermoplastic PMMA acrylic MOD group. Conclusion: Within the limitation of this study, it was concluded that the fabrication of single implant-retained MODs from thermoplastic PMMA acrylic resins improves masticatory muscle activity and overdenture survival.

The effect of two different attachments on patient satisfaction in mandibular class II and III ACP ridges with single implant-retained mandibular overdentures

Background: The American collage of Prosthodontics (ACP) classified completely edentulous patients into four classes based on specific diagnostic criteria. The aim of this randomized clinical trial is to compare patient satisfaction scores between ball and CMLOC attachment in class II and class III ACP for a single implant retained mandibular over-denture after 2 weeks of loading 1 and 2 year follow up. Materials and Methods: Eighty completely edentulous patients were recruited from the out-patient clinic of Prosthodontics Department –Cairo University. Patients with Class II and III ACP classification were included . All patients received a single implant in the mid line of the mandible. After a 3 month healing period, patients were randomized using sealed envelopes into ball attachment group and a CMLOC attachment group. Patient satisfaction questionnaire was used to record patient satisfaction for both groups 2 weeks after loading, then 1 and 2 years later. Results: For the Ball group, there was no statistically significant difference – in patient satisfaction scores between both ACP classes at all follow up periods. As for the CMLOC group, no statistically significant difference in patient satisfaction scores was found between both classes 2 weeks after loading, while at 1 year follow up, patients with class III showed statistically significant better patient satisfaction and at 2 year follow up there was no significant difference between both classes. Conclusion: The resiliency of the attachment and the associated denture base rotation seems to have a greater influence on patient satisfaction than the ACP classification.

Crestal Bone Changes and Patient Satisfaction with Single Implant-Retained Mandibular Overdentures with Dalla Bona and Locator Attachments with Immediate Loading Protocols. A Randomized Controlled Clinical Study.

There is no enough evidence present on the success of single implant-retained mandibular overdentures (SIMO) with Dalla Bona and Locator attachments. This study aims to compare crestal bone loss and patient satisfaction with SIMO with Dalla Bona and Locator attachment following immediate loading protocols. Twelve patients included in Group 1 received immediate SIMO with Dalla Bona attachments, and another twelve patients in Group 2 received immediate SIMO with Locator attachments in the mid symphyseal region. The follow-up was scheduled at 6 and 12 months after implant placement. The patient satisfaction with the denture was evaluated with the visual analog scale (VAS) score. The data obtained were statistically analyzed with the independent student t-test for intergroup comparison and repeated measures of ANOVA followed by Bonferroni's Post hoc analysis for intragroup comparison of mean crestal bone loss at a different time interval. Ten patients each in both the groups were available for follow-up. Crestal bone loss at 6 months follow-up for Dalla Bona group was 0.42 ± 0.10 mm on the mesial side and 0.43 ± 0.14 mm on the distal side and at 1 year 1.54 ± 0.16 mm on the mesial side and 1.66 ± 0.13 mm on the distal side. The mean crestal bone loss at 6 months follow-up for Locator group was 0.48 ± 0.16 mm on the mesial side and 0.45 ± 0.11 mm on the distal side and at 1 year was 1.71 ± 0.22 mm on mesial side and 1.74 ± 0.28 mm on the distal side. There was difference in bone loss at 6 months (mesial: 0.06 mm, p = 0.327; distal:0.02 mm; p = 0.726) and at 1 year (mesial: 0.17 mm, p = 0.063; distal: 0.08 mm; p = 0.423) in between two groups but the difference was statistically insignificant. There was a significant difference found in the VAS score for patient satisfaction with SIMO with Dalla Bona attachments and Locator attachments at 6 months (54.2 vs. 51.8, p = 0.005) and 1 year (60.6 vs. 55.2, p = 0.005). Patient satisfaction with SIMO with Dalla Bona attachments was higher during the follow-up. SIMO with Dalla Bona attachments had less crestal bone loss and less prosthetic complications when compared to Locator attachments, although the difference in the bone loss was statistically insignificant.

Preliminary study of clinical outcomes for single implant-retained mandibular overdentures.

This study evaluated marginal bone loss and prosthetic complications associated with single implant-retained mandibular overdentures (1-IODs) with locator attachments. The 1-IOD was placed in the mandibular midline by using a conventional loading protocol in 22 patients with an edentulous mandible. Marginal bone loss at the start of loading and 12 months postoperatively was assessed by radiographic and crestal bone evaluation. The crestal bone was defined as the distance between the customized abutment shoulder and the top of the bone, as indicated by probing. In addition, implant stability quotient and prosthetic complications were recorded. The cumulative implant survival rate was 95.5%. Median implant stability quotient remained greater than 80, and median radiographic bone loss was 0.56 mm. Crestal measurement showed a median crestal bone loss of 0.16, 0.43, 0.39, and 0.52 mm on the buccal, right, lingual, and left sides, respectively. Both radiographic and crestal bone loss values significantly differed between the start of implant loading and 12 months postoperatively (except on the buccal and lingual sides; P < 0.05). The need to replace the nylon insert was the most common complication. Conventional loading of a 1-IOD with a locator attachment resulted in a high survival rate, good implant stability, and acceptable marginal bone loss.

Ten-year clinical outcome of single implant-retained mandibular overdentures—A prospective pilot study

ObjectivesThe aim of this prospective pilot study was to evaluate the concept of one single implant placed in the edentulous mandible to retain a complete denture with regard to implant survival and prosthodontic maintenance over an observation period of 10 years. Materials and methodsEleven edentulous patients were included and received one implant in the midline of the mandible. Five implants healed submerge and were uncovered 2 months later. The other six healed un-submerged and were provided with a healing abutment 4 mm in height thus moderately loaded. All denture bases were temporarily relined during the healing period and two months later provided with a ball attachment for implant retention. Implant related parameters and prosthodontic maintenance interventions were assessed four weeks after implant loading and then annually. ResultsOver a mean observation period of 108.9 months (35–136 months), no implant was lost. The most frequent prosthetic maintenance intervention was activation of the matrix due to loss of retention, followed by exchange of the female part. Fracture of the denture base in the attachment area was a frequent complication and occurred in 8 cases. Two denture bases fractured twice. ConclusionWithin the limitations of this prospective pilot study, the concept of a single midline implant to retain a mandibular complete denture is promising over ten years for edentulous patients. Regular recall visits should be scheduled due to frequent maintenance interventions. Further research on this topic with a larger study cohort is needed.

The Implant stability and bone height changes for immediately loaded single implant-retained mandibular overdentures with locator attachments

Aim: The aim was to evaluate the efficacy of attachment placement on initial stability and bone height changes for immediately loaded single-implants retaining mandibular overdentures.&#x0D; Methodology: Twenty edentulous patients were recruited for this study; 9 females (45.0%) and, 11 males (55.0%) (age ranged from 59.0 to 70.0 year). Single endoosseos implant was inserted in the mandibular midline region. Immediately after surgery; Locator abutment was secured on the implant and the male housing was connected intraorally using direct pick-up procedure. Marginal bone height measurements and implant stability values were assessed at the time of implant placement (baseline), 2,4,6,8, 12, 24 weeks then every 6-month interval up to 18 months post-implant placement. &#x0D; Results: The implant stability values decreased markedly from the baseline, during 4 weeks and, then increased gradually until reaching the initial values after 12 weeks followed by continuous increase to study’s end (p&lt;0.05). The peri-implant marginal bone level revealed an acceptable range of bone loss with a statistically significant differences between different follow-up times and it continued to the end of the study (p&lt;0.05).&#x0D; Conclusion: Retaining an overdenture by immediately loaded single implant could be a successful treatment option for mandibular edentulous arches, especially in people with limited financial resources. The use of Locator attachment seemed to have a favorable effect on implant stability and marginal bone around immediately loaded single implant mandibular overdenture after 18-months of function.

Reinforcement of Single Implant-Retained Mandibular Overdenture with a Cobalt-Chromium Framework before Implant Surgery.

Previous clinical research has shown promising results in oral rehabilitation of elderly adults by a single implant-retained mandibular overdenture; however, the high incidence of fracture in the anterior region of these overdentures is a concern for clinicians. To minimize catastrophic overdenture fracture, we propose a technique to insert an individualized metal framework in single implant-retained overdentures prior to implant surgery.

Stress analysis at bone-implant interface of single- and two-implant-retained mandibular overdenture using three-dimensional finite element analysis.

The purpose of this research was to compare stress distribution on the bone between single implant-retained and two-implant-retained mandibular overdentures using three-dimensional (3D) finite element analysis. Two 3D finite element models were designed. The first model included single implant-supported mandibular overdenture placed in the midline of the mandible while the second model included two-implant-supported mandibular overdenture placed in the intra-foramen region, retained by ball attachment of the same diameter. The bone was modeled on the D2 bone depending on the classification given by Misch. A computed tomography scan of the mandible was used to model the bone by plotting the key points on the graph and generating the identical key points on the ANSYS Software (ANSYS, Inc., USA). The implant was modeled using appropriate dimensions as provided by the manufacturer. Stresses were calculated based on the von Mises criteria. Stresses produced in the hard bone (HB) and soft bone (SB) were higher in single implant-retained mandibular overdenture while stresses produced around the denture as well as implant were higher in two-implant-retained mandibular overdenture. Within the limitations of the study, it had been seen that stresses produced were the highest on HB and SB in single implant-retained mandibular overdenture while stresses produced across the denture as well as implant were the highest in two-implant-retained mandibular overdenture.

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.

Photoelastic Stress Distribution Produced by Different Retention Systems for a Single-Implant Mandibular Overdenture.

For patients poorly adapted to conventional dentures, the single-implant mandibular overdenture has been proposed as a simplified alternative for the two-implant treatment, together with the use of immediate loading of the implant. The aim of this in vitro study was to compare the photoelastic characteristics of stress transfer around the implant in a single-implant mandibular overdenture using different types of attachments. A photoelastic model of an edentulous mandible with a resilient edentulous ridge and a unique implant located at the symphyseal region was obtained to reproduce a single implant-retained mandibular overdenture. Six 2.0 mm height attachments were selected and inserted in the same photoelastic model in a random order. A universal testing machine was used to induce axial vertical loads of 70 Ncm applied at the central incisor and at the central region of the first right molar without contact on the contralateral side. The photoelastic analysis was performed using a polariscope integrated into the testing machine. Standard separate views were photographed, using only one model per system. A visual qualitative analysis of stress-induced fringes was performed to comparatively rank the different attachment systems. All attachments showed a similar tension distribution concentrated in the apical third, and the highest stress concentration was at the apical level. There was a low stress concentration at the coronal third of the implant, with no discernible stress in the first threads of the implants, except for Dalla Bona, which showed low stress at the coronal part of the implant (1 fringe). No identifiable fringes were observed when the load was applied in the molar region, which resulted from the low amount of stress transmitted by the implant for all attachments. The load transferred to a single mandibular implant was evenly distributed around the implant with low stress concentration, irrespective of the type of retention system.