Overdenture Design Research Articles

Comparison of the effects of implant locations and overdenture designs on the implants and bone stress: a finite element analysis

Objective The effects of implant locations and prosthesis design (palate less, full palate) on stress values of the implant and bone in maxillary overdenture prostheses were examined and compared with finite element analysis. Material and Methods Full palate and palate less four implant supported finite element overdenture models have created with different implant locations (M1: bilateral lateral 1. premolar, M2: canine 2. premolar, M3: 1. premolar 1. Molar). Static loads have applied with food stuff method on 1. Molar region. Von mises stress on implants and implant parts, maximum and minimum principal stress generated in peri-implant bone have calculated with finite element analysis method (FEA). Results As a result, it was observed that the palate less design creates more stress on the implants and bone compared to the full palate design. In addition, stress formation was observed to be higher in models with implant positions are posterior. Conclusion In implant supported overdentures (ISO), palatal coverage ensures more balanced distribution of stresses occurring around the implants and implant parts, regardless of the location of the supporting implants.

Analytical Modeling of the Interaction of a Four Implant-Supported Overdenture with Bone Tissue

Today, an interdisciplinary approach to solving the problems of implantology is key to the effective use of intraosseous dental implantations. The functional properties of restoration structures for the dentition depend significantly on the mechanical stresses that occur in the structural elements and bone tissues in response to mastication loads. An orthopedic design with a bar fixation system connected to implants may be considered to restore an edentulous mandible using an overdenture. In this study, the problem of the mechanics of a complete overdenture based on a bar and four implants was formulated. A mathematical model of the interaction between the orthopedic structure and jawbone was developed, and a methodology was established for the analytical study of the stress state of the implants and adjacent bone tissue under the action of a chewing load. The novelty of the proposed model is that it operates with the minimum possible set of input data and provides adequate estimates of the most significant output parameters that are necessary for practical application. The obtained analytical results are illustrated by two examples of calculating the equivalent stresses in implants and the peri-implant tissue for real overdenture designs. To carry out the final assessment of the strength of the implants and bone, the prosthesis was loaded with mastication loads of different localization. In particular, the possibilities of loading the prosthesis in the area of the sixth and seventh teeth were investigated. Recommendations on the configuration of the distal cantilever of the overdenture and the acceptable level and distribution of the mastication load are presented. It was determined that, from a mechanical point of view, the considered orthopedic systems are capable of providing long-term success if they are used in accordance with established restrictions and recommendations.

Evaluation of the Effects of Attachment Type and Implant Number on Life Quality of Implant-Supported Mandibular Overdenture Prosthesis Patients

Objective: The current study aimed to evaluate the life quality of implant-assisted mandibular overdenture patients who have had additional implant applications and were rehabilitated with ball or bar attachment. Material and Methods: 53 patients who came to Van Yüzüncü Yil University, Faculty of Dentistry, Prosthodontics Clinic for implant-supported mandibular overdenture treatment between 2019 and 2021 were included in this prospective clinical study (32 females, 30 males; mean age: 64.03; age range: 33-90). The patients were called back for the study precisely one year after prosthetic loading of their implants. Implant-supported mandibular overdenture prosthesis patients diverged into six groups: splinted two implants (bar attachment), single two implants (ball attachment), splinted three implants (bar attachment), single three implants (ball attachment), splinted four implants (bar attachment) and single four implants (ball attachment). And they asked for completing the Turkish version of the OHIP-14 questionnaire. Results: Ball attachment was used in 45.28% of the participants, a mandibular overdenture design supported by a bar attachment was preferred in 54.72%. Kruskal-Wallis test results indicated that the number of implants had a statistically significant effect only on functional limitation and psychological disability among the seven OHIP-14 categories evaluated (p=0.018, p=0.009). Accordingly, the average functional limitation score in individuals with four implants was 4.44 ± 1.89. Conclusion: We found that there are a positive correlation between the number of implants and the patient's life quality; however, it can be concluded that attachment type does not significantly affect the scores of the life quality

Immediately loaded single-implant mandibular overdentures compared to conventional complete dentures: A cost-effectiveness analysis

BackgroundIn recent years, the single-implant mandibular overdenture (SIMO) has been proposed as an alternative to more complex overdenture designs as a simplified implant intervention for edentulous patients. ObjectiveThe aim of this study was to run a cost-effectiveness analysis alongside a randomized clinical trial comparing the SIMO and the conventional complete denture (CCD) treatment. Imediately loaded external hexagon implant and ball attachment were used for the overdenture goup. Direct costs related to therapies were identified and valuated throughout a 1-year period after delivery, in Brazilian currency (R$) and converted into international dollars (I$) using purchase power parity exchange rates. Treatment effectiveness was measured using the OHIP-Edent and satisfaction scores for calculation of incremental cost-effectiveness ratios (ICER). ResultsOutcomes were assessed at the 1-year follow-up for 65 patients (CCD=34; SIMO=31). Overall OHIP-Edent and satisfaction scores improved significantly in the SIMO group, while remained unchanged in the CCD group. The mean overall costs were R$1,179.04 (I$590.99) for the CCD group and R$2,127.91 (I$1,068.20) for the SIMO group – 80.7% incremental cost for SIMO. The ICER calculation for SIMO treatment showed a mean cost of I$48.20 for 1-point reduction in OHIP-Edent scores, and I$12.56 for 1-point increase in satisfaction score. ConclusionsFindings support the effectiveness of this simplified and low-cost implant intervention for edentulous patients. SIMO also seems a cost-effective alternative to the CCD and the relatively low incremental cost may potentially increase the utilization of dental implants among older subjects, especially those with limited financial resources. Clinical significanceThe immediately loaded single-implant mandibular overdenture was superior to the conventional complete denture in terms of patient-reported outcome measures at a low incremental cost.

Root-retained overdentures: Survival of abutment teeth with precision attachments on root caps depends on overdenture design.

Root-retained overdentures (OD) are one treatment option for partially edentulous patients. However, the available evidence regarding factors influencing abutment survival in root-retained ODs is limited. This retrospective study included clinical examinations and evaluated the survival rate of roots restored with precision attachments soldered to post-and-core (gold cap) retained ODs, analysed with respect to various patient- and prosthesis-related factors. Patients receiving at least one OD with gold caps in the past were invited for comprehensive clinical examinations. The primary outcome parameter was the abutment survival rate over the observation period (2002-2016). Possible contributing factors (eg closed vs open OD design) were analysed. Analyses included Kaplan-Meier estimators, Cox regressions and hazard ratios (HR). 114 patients with 128 ODs originally retained by 280 abutments, with a cumulative total exposure time of 2035.4years, were examined. Twenty-seven abutment teeth (9.6%) were lost after a mean observation period of 7.9±3.4years. Significant factors associated with abutment loss were a closed, compared to an open OD design (HR 8.38 (95% CI 1.11-63.59), P=.040), which was independent of the number of abutments per OD. Furthermore, the loss rate was higher when the denture was not worn day-and-night (HR 3.52 (95% CI 1.32-9.40), P=.012). Oral hygiene behaviour was associated with higher HRs. ODs remain a viable treatment option for patients with few teeth remaining in the dental arch. It is advisable to choose an open design for the OD, irrespective of the number of abutment teeth. Furthermore, gold cap-retained ODs should not be removed overnight.

Effects of overdenture attachment systems with different working principles on stress transmission: A three-dimensional finite element study.

PURPOSEThe aim of the present study was to compare the stress distributions on the dental implants, abutments, and bone caused by different overdenture attachment types under functional chewing forces.MATERIALS AND METHODSThe 3D finite element models of the mandible, dental implants, attachment types, and prostheses were prepared. In accordance with a conventional dental implant supported overdenture design, the dental implants were positioned at the bone level in the canine teeth region bilaterally. A total of eight models using eight different attachment systems were used in this study. All the models were loaded to simulate chewing forces generated during the centric relationship (450 N), lateral movement (400 N), protrusive movement (400 N), and also in the presence of a food mass unilaterally (200 N). Stress outputs were obtained as the maximum principal stress and the equivalent von-Mises stress.RESULTSIn all attachment types, higher stress values were observed in the abutments, dental implants, and bone in the magnet attachments in different loading conditions. The highest stress values were observed among the magnet systems in the components of the Titanmagnetics model in all loading conditions (stresses were 15.4, 17.7, and 33.1 MPa on abutment, dental implant, and bone, respectively). The lowest stress value was observed in the models of Zest and O-Ring attachments.CONCLUSIONThe results of the present study implied that attachment types permitting rotation and tolerating various angles created lower stresses on the bone, dental implants, and abutments.

Splinting vs Not Splinting Four Implants Supporting a Maxillary Overdenture: A Systematic Review.

To investigate the influence of splinted vs unsplinted designs for a maxillary overdenture supported by four implants in terms of the outcome measures implant survival, overdenture longevity, and patient satisfaction. A systematic search, complemented by a handsearch, was carried out in the Embase, MEDLINE (PubMed), and Web of Science databases from 2000 to 2018. The PRISMA statement and a PICO approach were adopted. Free-text words were used in the strategy search, including "4-implant-retained overdenture," "4-implant-supported overdenture," "implant-supported overdenture," "implant-retained overdenture," "maxillary overdenture," "splinted design," "un-splinted design," and their combinations. All selected articles provided at least a 1-year follow-up, 10 fully edentulous patients, and at least one of the following clinical outcomes: survival rate of implants, survival rate of overdentures, and/or patient satisfaction scores. Nonparametric Fisher test for unpaired data was adopted in order to analyze data deriving from the survival rates of implants and overdentures. The initial electronic search produced a total of 2,922 articles. After applying the inclusion criteria, 14 articles were included. The mean follow-up time after implant placement ranged from 1 to 10 years. No statistical difference was detected in the survival rate of implants between the splinted implant group and the unsplinted implant group (P = .1). Only 4 included studies reported an overdenture survival rate of lower than 95%. It is interesting to note that among these 4 studies, 3 employed four splinted implants with a bar anchorage; however, no statistical difference was detected in the survival rate of overdentures between the splinted and unsplinted groups (P = .47). High scores were reported by all studies investigating patient satisfaction. Within the limits of this systematic review, it can be concluded that the survival rates of implants and overdentures and patient satisfaction with a maxillary overdenture supported by four implants were not influenced by the overdenture design, and no statistical difference was detected between the splinted and unsplinted groups.

Effect of mucosa thicknesses on stress distribution of implant-supported overdentures under unilateral loading: Photoelastic analysis

The aim of this study was to evaluate the effect of different heights of attachment and mucosa thicknesses on the stress distribution of two implant-retained mandibular overdenture designs under loading using the photoelastic stress analysis method. Six photoelastic models of an edentulous mandibula were fabricated with two solitary implants that were placed in the canine regions. The attachment systems studied were ball and locator stud attachments. Both the ball and locator groups included three models that had different residual ridge heights so as to provide different mucosa thicknesses (1 mm-1 mm, 1 mm-2 mm, 1 mm-4 mm). A static vertical force of 135 N was applied unilaterally (each on the right then the left side) to the central fossa of the first molars. Models were positioned in the field of a circular polariscope to observe the distribution of isochromatic fringes around the implants and the interimplant areas under loading. The photoelastic stress fringes were monitored and recorded photographically. The ball attachment groups showed higher stress values than did the locator groups under loading. Both attachment systems produced the lowest stress values in stimulated 1 mm-1 mm mucosa thickness models. The models with 1 mm-2 mm mucosa thicknesses showed higher stress values than did other models for both attachment systems. The highest stress value observed around both attachment systems was the moderate level in all test models. In different height mucosa thicknesses, locator attachment models distributed the load to the other side of the implant and its surrounding tissue, whereas the ball attachment did not. Regardless of mucosal thickness and attachment type, the implant on the loading side was subjected to the highest stress concentration.

Evaluation of Stress Distribution on Mandibular Implant-Supported Overdentures With Different Bone Heights and Attachment Types: A 3D Finite Element Analysis.

The biomechanical behavior of the edentulous mandible with bone irregularities that has been rehabilitated with implant-supported overdentures has become an important factor for treatment planning. Restorative options, including dental implants with various attachments, affect the stress distribution. The purpose of this study was to evaluate the stress distribution of cortical bone around the implant neck and implant structures in overdentures with two different attachment types at the edentulous mandible and with different bone heights using three-dimensional finite element analysis. Five three-dimensional models of an edentulous mandible were designed and implemented. Ten models were constructed with ball and locator attachments. Static bilateral and unilateral vertical and oblique occlusal loads with magnitudes of 100 N were applied to the overdentures. The principal stresses were higher in the presence of oblique loads compared to vertical loads in all the analyzed models. Maximum principal stresses were observed around the mesial side of the contralateral implant, and the minimum principal stresses were noted around the distal side of ipsilateral implant during unilateral vertical loading. These patterns were reversed during oblique loadings. The ball attachment models yielded lower von Mises stress values than the locator models at all the loading conditions, while the stress distributions were similar in the models with the same and different bone levels. Correspondingly, bone corrections due to irregularities may not be necessary in terms of biomechanics. The results of this study may provide clinicians a better understanding for the mandibular overdenture design in the cases at which different bone heights exist.

Patient-Reported Outcomes of Maxillary Edentulous Patients Wearing Overdentures Retained by Two Implants from Insertion to 4 Years.

This cohort study evaluated patient satisfaction for maxillary implant-retained overdentures (IODs) on two implants up to 4 years and assessed the treatment effect over time. Patients encountering problems with their conventional dentures were included and received maxillary IODs on two titanium-zirconium implants and ball anchors in the canine area. Patient satisfaction was assessed using the oral health impact profile (OHIP-20E) questionnaires both for dentures and IODs. Two months after insertion of IODs (baseline), the patients chose the preferred overdenture design with full or reduced palatal coverage. OHIP-20E questionnaires were followed according to the individual choice at 1 and 4 years, and outcomes were compared with baseline. Sixteen out of 21 patients were evaluated at a mean follow-up of 4 years (range: 2.4 to 4.8 years). There was no significant difference in the OHIP domains for IODs at 1 year (OHIP_total_1y: 9.5, SD: 13.0) and 4 years (OHIP_total_4y: 14.2, SD: 19.1) compared with baseline (OHIP_total_BL: 12.4, SD: 14.7). Patients were most satisfied with social disability both for IODs (OHIP_BL: 6.0, SD: 7.6; OHIP_1y: 3.4, SD: 5.4; OHIP_4y: 5.7, SD: 9.5) and dentures (OHIP_CD_old: 28, SD: 29.7; OHIP_CD_new: 25.4, SD: 28.67). Patients were least satisfied with functional limitation both for IODs (OHIP_BL: 6.0, SD: 7.6; OHIP_1y: 3.4, SD: 5.4; OHIP_4y: 5.7, SD: 9.5) and dentures (OHIP_CD_old: 28, SD: 29.7; OHIP_CD_new: 25.4, SD: 28.67). Patient satisfaction with maxillary IODs on two implants did not change from baseline to 4 years and was high at 4 years of function.

Comparison of Stress Patterns in Edentulous Mandibular Bone Around Two Implant Retained, Four Implant Retained Overdenture and All-On-Four Concept-A 3 Dimensional Finite Element Analysis

Recently the use of tilted implants has been considered as a preferable option in case of atrophic edentulous arches. The tilted longer implants can be of use to ward off the important anatomical structures while also permitting cantilever reduction. Since the load transfer mechanism of an implant can be altered significantly by the number of implants and its location in the edentulous ridge, the present study evaluates and compares the stress patterns in the edentulous mandibular bone around two implant retained, four implant retained over denture and all on four concepts under different loading conditions using finite element analysis. Purpose: The biomechanical behaviour of the ‘All-On-Four’ system was compared with that of the two implant-supported and four-implant supported mandibular overdenture using the three dimensional finite element method (FEM). Thereby evaluating the von Misses stresses induced on the implants under different loading simulations. Materials & Method: Three dimensional models representing mandible restored with ‘All-On-Four’, two implant-supported and four-implant-supported prosthesis were developed in the three dimensional design software and then transferred into FEM software. The models were then subjected to four different loading simulations (full mouth biting, canine disclusion, load on cantilever, load in the absence of cantilever). The maximum von Mises stresses were localized and quantified for comparison.1 Results: Among the three models, under all loading simulations, the maximum stress concentrations werealong the neck of the implant. The stress levels for full mouth loading simulation was highest for twoimplant supported overdenture design and the least for All-On-Four overdenture design. In all three designs,the least stress was when the implants were loaded in a lateral direction. The stress levels for cantilever andnon-cantilevered designs were nearly the samefor all the simulated designs. Conclusion: When tested under differentloading simulations, the three modelsshowed similar location and distribution ofstress patterns. Thus from the study it can beconcluded that the All-On-Four Concept is a clinically applicable treatment option for the atrophic edentulous ridges and induces least amount of stresseson the edentulous ridges. Therefore the overall longevity of the prosthesis is greatly enhanced.

Magnetic Attachment Retained Complete Overdenture as Treatment for Maintaning Alveolar Ridge Height – A case report

Background: Magnetic attachment can be used as a retentive devices in overdenture technique in prostheses. The magnets are attached with remaining root structure transfer the occlusal load to the bone through the periodontal ligament of retained roots and then prevent resorption of the alveolar ridge. Alvelar ridge plays an important role for the retention and stability of the denture as they will support the denture base. Magnetic assembly consist of magnet and coping with a keeper on the remaining tooth structure since magnetic attachment can provide support, stability and retention. Purpose: The purpose of this case report was to report magnetic attachment retained complete overdenture design and fabrication as a preserve to alveolar bone height to achieve retention and stability of the denture. Case: A 69 years old female patient, a baker and private English teacher with partial edentulous ridge came to Dental Hospital of Airlangga University asked for dentures. Clinical examination shown a complete edentulous in the upper jaw and partial edentulous in the lower jaw. The remaining teeth were 33, 34, 35, 43 and 44. 33 and 35 are chronic gangrene radix, 35 shown a slightly mobility. 34 non vital, 44 and 45 are vital with moderate resorption. Case management : All the left teeth in the lower jaw were consulted for endodontic treatment. Magnetic attachment retained complete overdenture was choosen for the lower jaw and complete denture for the upper jaw. The remaining teeth in the lower jaw kept the alveolar ridge from resorption and the magnet provided extra retention for the complete overdenture. Discussion: Overdentures supported by magnet attachment achieved greater satisfaction, gives better retention and stability for the denture. On the other side, the natural abutment teeth in overdentures preserved better proprioception and psychologically beneficial as the patient had not undergone extraction. As a conclusion, overdenture supported by magnetic attachment can be used to increase support, retention and stability especially in the lower jaw and also prevent further alveolar ridge resorption. Conclusion: Overdenture supported by magnetic attachment can be used to increase retention and the residual root also prevent further alveolar ridge resorption.

Telescopic Overdenture as An Aesthetic Treatment for Partially Dentate Patients – A case report

Background: Metal frame denture design is common used for partially dentate patient, one of the problem was a metal appearance from wrought wire or a metal casting clasp as retainer, which is not really aesthetic. Telescopic overdenture with its double crown will be the best solution for those cases. Purpose: The purpose of this case report was to reported telescopic overdenture design and fabrication where the aesthetic was the main consideration. Case: Sixty years old female patient, a businesswoman, came to Dental Hospital of Universitas Airlangga, complained about her upper partially dentate and 6 years lower fixed partial denture, which is not comfortable to wear and her upper anterior teeth doesn’t look quite good. She wanted to make crowns and removable denture. Case management: After the diagnosis were made, the pretreatment plan were remove crown for the upper jaw, remove the bridges on lower jaw, and transitional dentures were made to maintain the VDO. The crowns and veneer were fabricated and inserted while the inner copings were tried up on prepared teeth. After the the dentures were produced, the inner copings were luted to the abutment teeth, and then the dentures were inserted using FGP (Friction GriP) cement for the friction effect. Discussion: Telescopic overdenture is consists of a double crown system known as “the telescopic”, the procedure involves fitting the remaining natural teeth with inner metal crowns, followed by outer crowns as part of an over denture that can be removed by the patient. Conclusion: This technique ensures that telescopic overdentures give natural aesthetic result.

Clinical Performance of Implant Overdenture Versus Fixed Detachable Prosthesis

To evaluate the satisfaction of completely edentulous patients with a different number of implants to retain removable and support the fixed prosthesis. Fifty patients with the single edentulous ridge (maxilla or mandible) were selected for this study and divided equally into five groups. Each group contained 10 patients. Group 1: conventional complete denture (negative control group), group 2: two implants retained overdenture, group 3: three implants retained overdenture, group 4: four implants retained overdenture, group 5: fixed detachable prosthesis with five implants placed between the mental foramen. After one year from completing the treatment, the patients were requested to fill a specially designed questionnaire to assess their overall quality of life and level of satisfaction, both estheti-cally and functionally. Comparison of data between groups was performed using the Chi-square tests. The level of statistical significance was considered at p < 0.05. Patients treated with conventional complete denture were all unsatisfied in their masticatory function, and 80% were also unsatisfied in phonetics, while only 50% of patients were satisfied aesthetically and mentally and 70% were satisfied in social life. The addition of two or more dental implants resulted in 100% satisfaction in the variables tested. There was no statistical difference between the number of implants and supra-structure design regarding patients' satisfaction. Furthermore, implants retained overdenture and fixed detachable prosthesis design scored the same satisfactory level. The satisfaction level of the conventional complete denture in the treatment of an edentulous arch can be dramatically improved by adding dental implants and changing the design to an overdenture. Two implants with an overdenture design is a valid treatment option for the edentulous arch as well as three and four implants. Fixed detachable prosthesis did not add any further patient satisfaction when compared to implant retained overdenture. Two implants with overdenture to treat edentulous jaw is effective as five implant fixed prosthesis.

Load Transfer Characteristics of Three-Implant–Retained Overdentures with Different Interimplant Distances

Implant-retained overdentures are the first choice of rehabilitation for edentulous mandibles. Bone morphology and anatomical landmarks may be influenced by the location and angulation of implants and distances between the implants. The purpose of this study was to investigate stress distribution characteristics and to compare stress levels of three different attachment designs of three-implant-retained mandibular overdentures with three different interimplant distances. Three photoelastic mandibular models with three implants were fabricated using an edentulous mandible cast with moderate residual ridge resorption. The center implants were embedded parallel to the midline, and the distal implants were aligned at a 20-degree angulation corresponding to the center implants. Distances between the center and distal implants were set at 11, 18, and 25 mm at the photoelastic models. Bar, bar-ball, and Locator attachment-retained overdentures were prepared for the models. Vertical loads were applied to the overdentures, and stress levels and distribution were evaluated by a circular polariscope. The greatest observed stress level was moderate for the tested overdenture designs. The Locator attachment system showed the lowest stress level for the 11-mm and 25-mm photoelastic models. The bar attachment design transmitted less stress compared with the other tested designs for the 18-mm photoelastic model. Stresses were observed on the loaded side of the photoelastic models. The lowest stress was found with the Locator and bar attachments for the 11-mm photoelastic model, which transmitted little or no discernible stress around the implants.

Retention of implant-supported overdentures at different implant angulations: comparing Locator and ball attachments.

To assess the effect of implant angulation on the retention of two different attachment systems for implant-supported overdentures after a simulated fatigue period of 5.5years. Two test set-ups were constructed. A two-implant mandibular implant-supported overdenture design was simulated using acrylic resin blocks to support implant replicas (Model 1 and Model 2). The replicas were set up in the canine regions (22-mm inter-implant distance). In Model 1, the implants were parallel (0° to the vertical axis) and in Model 2 they were divergent (20° to the vertical axis). The Locator and the ball attachment systems were tested at both set-ups. A simulated fatigue period of 5.5years that equated to 10,000 cycles of insertion and removal of the denture was used. Retention values for each attachment system at each angulation set-up were measured at baseline, every 500 cycles until 4000 cycles and then every 1000 cycles. After simulated fatigue, the retention for both systems at both set-ups reduced. The Locator system reduced from 108.9 to 20.2N in the parallel set-up and from 82.3 to 17.3N in the divergent set-up. For the ball system, the retention reduced from 56.2 to 46N when parallel and from 45.7 to 40.7N when divergent. Both attachment systems showed a significant reduction in retention after simulated fatigue at both parallel and divergent set-ups. The change in implant angulation caused a significant reduction in retention for the ball attachment system only, although this was still higher at the end of testing than the Locator attachment system. The Locators also had a significantly faster rate of loss of retention at both set-ups. Clinically, this may indicate that the ball attachments may perform better with divergent implants.

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 Esthetic Salutation and Functional Acceptance of Maxillary Superimposed Prosthesis

ABSTRACT In cases where patients are left with few teeth, clinicians face a dilemma. Psychological satisfaction of the patient by retaining the natural teeth not only provides retention but also helps in the preservation of the alveolar bone and proprioception. Overdenture therapy has a long-term advantage where the forces of mastication are directed along the long axis of the abutment teeth, which provides guidance and support and further prevents the dislodgement of denture during movements. Overdenture design remains one of the best treatment options for patients who do not have the financial ability to support an extensive restorative treatment. This management is a preventive prosthodontic therapy, which can delay or eliminate future prosthodontic problems. This case report is about the prosthetic rehabilitation of a partially edentulous patient using a hybrid overdenture with a double crown for the maxilla and conventional overdenture for the mandible, giving the patient a denture with better esthetics, more support, and retention. How to cite this article Rajeev V, Arunachalam R, Ganapathy S, Vedam V. The Esthetic Salutation and Functional Acceptance of Maxillary Superimposed Prosthesis. World J Dent 2016;7(2): 107-110.

Biomaterial aspects: A key factor in the longevity of implant overdenture attachment systems.

Background:New attachment systems are released for mandibular two-implant overdentures often without evidence-based support. Biomaterial aspects are now the parameters considered when choosing the appropriate attachment. Studies regarding their properties remain scarce.Purpose:The purpose of this review was to help the clinician in selrcting the most adapted stud attachments according evidence-based dentistry.Materials and Methods:An electronic search was conducted using specific databases (PubMed, Medline, and Elsevier libraries). Peer-reviewed articles published in English up to July 2014 were identified. Emphasis was given on the biomaterial aspects and technical complications. No hand search was added.Results:The electronic search generated 115 full-text papers, of which 84 papers were included in the review. The majority were clinical and in vitro studies. Some review articles were also considered. Papers reported survival and failures of overdenture connection systems. Emphasis was laid on attachment deformation.Conclusion:Implant overdentures long-term follow-up studies may provide useful guidelines for the clinician in selecting the type of attachment system and overdenture design. Locator attachments are more and more used, with lesser complications reported.

Effect of the Number of Supporting Implants on Mandibular Photoelastic Models with Different Implant‐Retained Overdenture Designs

The purpose of the study was to evaluate the effect of the number of supporting implants and different retentive mechanisms on load transfer characteristics of mandibular overdentures. Two photoelastic models of edentulous mandibles were fabricated having two and four cylindrical implants (Calcitek, 4 × 13 mm) embedded in the parasymphyseal area. Four attachment systems were evaluated: single anchor attachment (ERA), bar-clip, bar with distally placed ball attachments, and bar with distally placed extracoronal rigid attachments (Easy Slot). A 133 N vertical force was applied unilaterally to the central fossa of the right first molar. The resulting stresses of the models were observed and recorded photographically in the field of a circular polariscope. The highest stresses were observed with the bar with distally placed extracoronal rigid attachment (Easy Slot) design, followed by bar-ball, bar, and the single anchor attachment (ERA) for both models. The lowest stress was observed with the single anchor attachment (ERA) design for both models. There were slight differences in stress values around implants in both models. For all tested attachments on both models, the stress was concentrated on the ipsilateral implant. The bar-clip system allowed the distribution of load to all supporting implants in both models. Although the highest stress level observed with all attachment systems was moderate, the bar-Easy Slot attachment showed the highest stresses. The lowest stress was observed with the single anchor attachment (ERA) design for both models. Varying the number of implants had no significant effect on stress values around supporting implants.