Rehabilitation of the completely edentulous young patient with the "Malo Bridge": A case report.

It is possible to rehabilitate fully edentulous patients with implantsupported fixed or removable prostheses; however, implantsupported fixed prostheses are the gold standard for patients who not prefer to use removable dentures. This case report, prosthetic rehabilitation of a completely edentulous young patient with an implantsupported fixed hybrid prosthesis using the "Malo Bridge" technique is described. A 18 years old male patient was referred to the clinic with complaints of tooth loss, aesthetics, function, and phonetic. A total of 5 implants were placed in both the jaws. Considering that screw holes may cause aesthetic problems due to the Class III occlusion, these problems have been solved with the implant-supported hybrid prosthesis called Malo bridge. With the Malo Bridge design, the patient's aesthetic, functional and phonetic loss was eliminated, patient comfort and quality of life were improved, and patient expectations were met. It is a viable treatment option to rehabilitate completely edentulous jaws with a cross relationship and increase interarch distance using Malo Bridge to support a fixed prosthesis.

Effect of Different Bar Designs on Axial and Nonaxial Retention Forces of Implant-Retained Maxillary Overdentures: An In Vitro Study.

PURPOSE: This in vitro study aimed to evaluate and compare the effect of different bar designs on the retention forces of implant-retained maxillary overdentures. MATERIALS AND METHODS: A maxillary edentulous acrylic resin model without alveolar undercut was fabricated. Four implant analogs were placed in the canine and second premolar regions. Overdentures were made and attached to the analogs with Dolder bar, Hader bar, and milled bar attachments. A universal testing machine was used to measure axial (resistance to vertical displacement) and nonaxial (resistance to anterior, posterior, and lateral displacement) retention forces (in Newtons). Measurements were made at the start of the experiment (initial retention) and after 540 cycles of denture insertion and removal to simulate 6 months of clinical function (final retention). RESULTS: Hader bar had the highest retention after insertions and removals, and Dolder bar had the lowest retention. Vertical displacement showed the highest retention for Dolder and milled bars, and posterior displacement showed the highest retention for Hader bar. Lateral displacement recorded the lowest retention for all bar designs. No significant difference in axial retention loss was observed between different bar designs. Dolder bar showed the highest nonaxial retention loss, and milled bar showed the lowest retention loss. CONCLUSION: Hader bar is recommended to retain maxillary implant overdentures, as it was associated with higher axial and nonaxial retention compared with Dolder and milled bars after 6 months of simulated denture wear.

Customized Cheek Plumper with Friction Lock Attachment for a Completely Edentulous Patient to Enhance Esthetics: A Clinical Report.

Prosthetic rehabilitation of a completely edentulous patient should never be restricted to the replacement of missing teeth. The ultimate aim of complete denture treatment should be restoration of the full range of oral functions and esthetics. Slumped cheeks are always a concern for esthetically demanding complete denture patients. This article describes a simple, scientific, cost-effective technique to improve facial esthetics in a completely edentulous patient with the help of a cheek plumper. The technique used here implements the concept of neutral zone to precisely determine the amount of space available for the cheek plumper. The simple friction lock attachments that retained the cheek plumpers on the prosthesis were also fabricated after determining the space available in the appropriate areas. Thus an effort was made to keep the cheek plumpers unobtrusive yet effective to ensure complete integration of the prosthesis into the stomatognathic system.

Locator Versus Bar Attachment Effect on the Retention and Stability of Implant-Retained Maxillary Overdenture: An In Vitro Study.

PURPOSE: To compare retention and stability of Locator and bar attachments for implant-retained maxillary overdentures. MATERIALS AND METHODS: Four implants were inserted into a maxillary acrylic resin model in canines and second premolar areas. Experimental overdentures were connected to the implants with bar (group I) or Locator (group II) attachments. Locators were divided into 3 subgroups according the degree of retention of the patrix nylon insert: Locator blue (group IIa), Locator pink (group IIb), and Locator transparent (group IIc). Retention (vertical dislodging) and stability (lateral, anterior, posterior dislodging) forces (N) were measured at the start of the experiment (initial retention) and after 540 cycles of denture insertion and removal (final retention). RESULTS: The highest initial and final stability was recorded with group IIc, followed by group IIb and group IIa, and the lowest retention and stability was noted with group I. For all groups, the highest final retention and stability forces were noted with vertical dislodging, followed by posterior dislodging, anterior dislodging, and lateral dislodging. The highest loss of retention and stability was recorded with group I, followed by group IIc, group IIb, and group IIa. CONCLUSION: Locator attachments are recommended to retain maxillary overdentures over Dolder bar attachments, as Locator attachments were associated with high retention and stability after wear simulation with minimal retention loss.

Fabrication of a Simple Acrylic Template to Standardize Periapical Radiographs for Implants Retaining Mandibular Bar Overdentures.

A standardized periapical radiograph is still the most suitable technique for monitoring peri-implant osseous destruction during long-term treatment. This article describes a new method for custom fabrication of an acrylic template with standardized reproducible assessment of implants retaining mandibular bar overdentures, without removal of the bar and regardless of the implant system used.

The Friction Clasp.

This clinical report describes a modification of the conventional direct retainer design, which incorporates advantages of the dual path partial denture, but with a greater ease of design and fabrication. The main advantage of this technique is minimizing the clasp display on Class III and Class IV removable partial denture prostheses. A clinical example using this design is described.

[A PhD completed. Maxillary overdentures: with a bar attachment system or locators?] / Serie: Hora est. De overkappings­prothese in de bovenkaak: op een staafmesostructuur of locators?

An overdenture on implants is the treatment of choice for patients with complaints about their conventional complete dentures. While a lot is known regarding the performance of implant-supported mandibular overdentures, much less is known regarding the performance of implant-retained maxillary overdentures. In this doctoral dissertation, various aspects of overdentures on 4 dental implants in the maxilla are discussed. From a systematic review of the literature, it appeared that an overdenture (maxillary or mandibular) on implants improved chewing efficiency, increased maximum bite force and increased patient satisfaction. Implants placed with a maximum dehiscence of two thirds of the buccal implant surface also appeared to function well after 5 years. An overdenture with a bar attachment system was associated with less marginal bone loss, a better subjective chewing efficiency and greater patient satisfaction than an overdenture retained by locators. The differences were, however, small and from a cost-effectiveness point of view, the use of overdentures retained by locators would not be a bad choice.

Clinical and Radiographic Evaluation of Bar, Telescopic, and Locator Attachments for Implant-Stabilized Overdentures in Patients with Mandibular Atrophied Ridges: A Randomized Controlled Clinical Trial.

PURPOSE: The aim of this study was to evaluate the clinical and radiographic peri-implant tissues of bar, Locator, and resilient telescopic attachments for two-implant stabilized overdentures in subjects with mandibular atrophied ridges. MATERIALS AND METHODS: Ninety edentulous individuals with mandibular ridge atrophy were randomly assigned into three equal groups and received two implants in the canine areas. Mandibular overdentures were constructed and attached to implants with Dolder bar attachments (BOD), resilient telescopes (TOD), and Locators (LOD). Plaque scores, gingival scores, pocket depths, implant stability, width of keratinized mucosa, vertical bone loss, and horizontal bone loss were evaluated at the time of prosthesis delivery and 6 months and 12 months after delivery. RESULTS: With the exception of pocket depth and implant stability, all parameters showed a significant increase from prosthesis delivery to 6 months. BOD recorded the highest plaque scores, gingival scores, and pocket depths followed by LOD, and TOD recorded the lowest values. No significant difference in implant stability and keratinized mucosa was observed between groups. TOD and BOD recorded the highest vertical and horizontal bone losses, respectively. LOD recorded the lowest vertical and horizontal bone losses. There was no difference in implant survival rate between groups. CONCLUSION: Bar, resilient telescopic, and Locator attachments can be used successfully for two-implant stabilized overdentures in subjects with mandibular atrophied ridges after a 1-year follow-up period. Telescopic attachments were associated with improved clinical peri-implant soft tissues compared with other attachments. However, Locator attachments may be advantageous in terms of peri-implant bone preservation.

Influence of Cross-Section Design and Vertical Misfit on Stress Distribution in Overdenture Retaining System: 3-Dimensional Finite Element Analysis.

PURPOSE: To evaluate by 3-dimensional (3-D) finite element analysis the stress generated on overdenture-retaining bar system with different cross sections (round, ovoid, or Hader) and misfit levels (50, 100, and 200 µm) manufactured with different metallic alloys (Au type IV, Ag-Pd, Ti cp, and Co-Cr). MATERIALS AND METHODS: Three-dimensional finite element models were modeled using specific 3-D software (SolidWorks) and imported into mechanical simulation software (ANSYS). A displacement simulating the settlement of the screw was performed until the infrastructure was settled properly on the prosthetic platform. RESULTS: Higher misfit levels caused higher stress on the overdenture-retaining bar system components, where (1) Hader bar presented the highest values (bar = 730.71; screw = 59.66, and periimplant bone tissue = 42.96, in megapascal) and (2) round bars made with type IV Au alloy presented lower stress values on the bar framework (193.99 MPa) and screw (10.27 MPa). CONCLUSIONS: Higher vertical misfit increased the stress values on the overdenture-retaining bar system; complex cross-sectional designs increased stress values on the bar framework, prosthetic screw, and periimplant bone tissue; stiffer alloys caused higher stress values on all the studied conditions.

An analytical model to design circumferential clasps for laser-sintered removable partial dentures.

OBJECTIVE: Clasps of removable partial dentures (RPDs) often suffer from plastic deformation and failure by fatigue; a common complication of RPDs. A new technology for processing metal frameworks for dental prostheses based on laser-sintering, which allows for precise fabrication of clasp geometry, has been recently developed. This study sought to propose a novel method for designing circumferential clasps for laser-sintered RPDs to avoid plastic deformation or fatigue failure. METHODS: An analytical model for designing clasps with semicircular cross-sections was derived based on mechanics. The Euler-Bernoulli elastic curved beam theory and Castigliano's energy method were used to relate the stress and undercut with the clasp length, cross-sectional radius, alloy properties, tooth type, and retention force. Finite element analysis (FEA) was conducted on a case study and the resultant tensile stress and undercut were compared with the analytical model predictions. Pull-out experiments were conducted on laser-sintered cobalt-chromium (Co-Cr) dental prostheses to validate the analytical model results. RESULTS: The proposed circumferential clasp design model yields results in good agreement with FEA and experiments. The results indicate that Co-Cr circumferential clasps in molars that are 13mm long engaging undercuts of 0.25mm should have a cross-section radius of 1.2mm to provide a retention of 10N and to avoid plastic deformation or fatigue failure. However, shorter circumferential clasps such as those in premolars present high stresses and cannot avoid plastic deformation or fatigue failure. SIGNIFICANCE: Laser-sintered Co-Cr circumferential clasps in molars are safe, whereas they are susceptible to failure in premolars.

Splinted and unsplinted overdenture attachment systems: A systematic review and meta-analysis.

Splinted and unsplinted overdenture attachment systems have unique advantages and disadvantages. The aim of the present systematic review was to determine the influence of splinted and unsplinted overdenture attachment systems on the marginal bone loss, prosthetic complications and implant survival rate. PubMed/MEDLINE, Scopus and Cochrane databases were searched for articles published up to October 2017, using the following search terms: "overdenture AND attachment OR overdenture AND bar OR overdenture splinted." The PICO question "Do splinted overdenture attachment systems promote better clinical results in comparison to unsplinted systems?" was evaluated. Eligible studies included randomized controlled clinical trials, prospective studies with at least 10 participants and a minimum follow-up of 6 months, and studies published in English that compared splinted and unsplinted attachment systems within the same study. The 95% confidence interval (CI) was considered for all outcomes analysed. After completion of the different steps in the article selection process, nine articles were included in the qualitative and quantitative analyses. A total of 984 implants were placed in 380 patients (mean age: 62.8 years). The meta-analysis demonstrated no statistically significant differences between splinted and unsplinted attachment systems with regard to marginal bone loss (P = .39; MD: -0.11; 95% CI: -0.37 to 0.14), complications (P = .31; RR: 1.26; CI: 0.80-1.99) and implant survival rate (P = .14; RR: 0.37% CI: 0.10-1.36). In addition, splinted and unsplinted overdenture attachment systems achieved similar results with regard to marginal bone loss, prosthetic complications and implant survival rate.

The In Vitro comparison of the retention of an implant-supported stud attachment locator and straumann ball attachment at different angulations.

AIM: In this study, we investigated the retention of two attachment types, Straumann ball (SB) and Straumann Locator® (SL) attachments, on different implant angulations and identified the most appropriate treatment type or attachment system for each angulation. MATERIALS AND METHODS: The attachments placed on angulation of 0°-, 10°-, and 20° implants were subjected to 1440 vertical insertion-separation cycles. The retention values of the attachments after 0, 720, and 1440 cycles were measured using the Instron machine. In addition, scanning electron microscopy images of the attachments and abutments were obtained before and after the insertion-separation process. RESULTS: There was a significant difference between the SB and SL attachments that were placed on 0° after 1440 cycles (P < 0.05) and between 20° SB and 20° SL attachments after 720 and 1440 cycles (P < 0.05) in terms of retention. No significant difference was observed between 20° SB and 20° SL attachments at 0 cycles (P > 0.05). CONCLUSIONS: In implants with a 20° angle, retention of stud attachments decreased more than ball attachments after use. Thus, the total angle between the implants should not be <20° if long-term retention is desired when using stud attachments. For implants with angles >20°, 6-month patient controls are required to control retention of attachments by considering factors in the mouth with the two tested attachment systems.

Retentive Properties of O-Ring and Locator Attachments for Implant-Retained Maxillary Overdentures: An In Vitro Study.

PURPOSE: To evaluate and compare retentive properties of O-ring and Locator attachments for implant-retained maxillary overdentures. MATERIALS AND METHODS: Four implant analogs were inserted in canine and second premolar areas of an acrylic edentulous maxillary model. A metal-reinforced experimental acrylic overdenture was constructed and connected to the analogs using either O-ring (group I) or Locator (group II) attachments. Locators were divided into 3 subgroups according the degree of retention of the patrix nylon insert: Locator extra-light retention (group IIa), Locator light retention (group IIb), and Locator medium retention (group IIc). Vertical and oblique (lateral, anterior, and posterior) dislodging forces were measured at the beginning of the study (initial retention) and after 540 cycles of denture insertion and removal (final retention). RESULTS: For vertical, lateral, and anterior dislodging, group IIc recorded the highest initial and final retention, and group I recorded the lowest retention. For posterior dislodging, group I recorded the highest retention, and group IIa recorded the lowest retention. For group II, vertical dislodging recorded the highest initial and final retention, and lateral dislodging recorded the lowest retention. For group I, posterior dislodging recorded the highest initial and final retention, and lateral dislodging recorded the lowest retention. For all dislodging forces (except posterior dislodging), the highest retention loss was recorded in group I, and the lowest retention loss was recorded in group IIa. CONCLUSION: Locator medium attachment was associated with favorable retention during axial (vertical) and nonaxial (anterior and lateral) dislodging compared to other types of Locator inserts and O-ring attachments after a simulated 6-month period of overdenture use.

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

BACKGROUND: Implant-supported overdenture is one of the most predictable treatment options used in complete edentulism. However, differences have been reported between bar and ball attachments used to retain overdentures in terms of patient satisfaction and prosthesis retention. PURPOSE: The purpose of this study is to compare the effectiveness of bar and ball attachments for conventionally loaded implant-supported overdentures in completely edentulous patients to improve patient satisfaction and prosthesis retention. MATERIALS AND METHODS: We conducted the review according to the Cochrane methods and following MECIR standards. We searched Cochrane Oral Health Group Trial register, Cochrane Central Register of Controlled Trials, MEDLINE, and the WHO ICTRP (March 31, 2017). Two review authors assessed trials for inclusion and risk of bias, extracted data, and checked for accuracy. We have expressed results as risk ratio or mean differences, together with their 95% confidence intervals. RESULTS: We included 10 trials (465 participants). After 5 y, one trial reported higher patient satisfaction when bar attachment was used (MD 1.30, 95% CI 0.20-2.40), and reported no difference between both systems in prosthesis retention (MD -0.90, 95% CI -1.90 to 0.10). Two trials reported no implant failures after 1 and 5 y in both attachments. Downgrading of evidence was based on the unclear risk of bias of included studies and the wide CI crossing the line of no effect. CONCLUSIONS: There is insufficient evidence to support bar or ball attachment to be used with implant-supported overdentures in completely edentulous patients to improve patient satisfaction and prosthesis retention (PROSPERO 2014:CRD42014014594).

Peri-implant strain around mesially inclined two-implant-retained mandibular overdentures with Locator attachments.

This study aimed to evaluate the peri-implant strain around mesially inclined implants used to retain mandibular overdentures with Locator resilient attachments. Four mandibular edentulous acrylic resin models received two implants in the canine areas with 0°, 5°, 10°, and 20° mesial inclinations. Overdentures were connected to the implants using Locator attachments. Pink nylon inserts (light retention) were used for all implant inclinations, and red inserts were used for 20° inclination (20°red). Four strain gages were bonded on the mesial (M), distal (D), buccal (B), and lingual (L) surfaces of each implant. Peri-implant strains were measured during bilateral and unilateral loading. The 20° inclination showed the highest strain, followed by 10° and 5°, and both 0° and 20°red presented with the lowest strain. Site D was associated with the highest strain, followed by M, B, and L, which showed the lowest strain values. Unilateral loading and the loading side presented with significantly higher strain values than bilateral loading and the nonloading side, respectively. Hence, in this study, strains around the two-implant-retained overdentures with Locator attachments increased with increases in mesial implant angulation, except when red male inserts were used.

Clips vs Resilient Liners Used With Bilateral Posterior Prefabricated Bars for Retaining Four Implant-Supported Mandibular Overdentures.

The objective of this research was to clinically compare peri-implant tissue health of bar-clips vs silicone-resilient liners used with bilateral posterior bars for retaining 4 implant-supported mandibular overdentures. Thirty completely edentulous male patients (mean age, 65 years) were randomly assigned into 2 equal groups. Each patient received 4 implants in the canine and first molar regions of the mandible using a flapless surgical technique. Mandibular overdentures were immediately connected to the implants with bilateral prefabricated instant adjusting bars. According to the method of retention to the bar, 1 group was retained with clips (GI), whereas the other group was retained with a silicone-resilient soft liner (GII). Peri-implant tissue health was evaluated clinically in terms of plaque scores (MPI), bleeding scores (MBI), probing depth (PD), and implant stability (IS). MPI, MBI, and PD were measured at mesial, distal, buccal, and lingual surfaces of each implant. Evaluations were performed 2 weeks (T0), 6 months (T6), and 12 months (T12) after overdenture insertion. Implants of GI with clips demonstrated significant increase in plaque, bleeding, and PD scores compared with those of GII with silicone-resilient liner at all observation times. Implants in GI demonstrated a significant decrease in implant stability compared with those of GII at T6 and T12 anteriorly and at T12 posteriorly. Resilient liners are considered better than bar-clips when used with bilateral posterior bars for retaining implant-supported mandibular overdentures in terms of peri-implant soft tissue health. Bilateral posterior ready-made bars cannot be proposed as a promising design for supporting implant-assisted mandibular overdentures.

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

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Carbon fibre versus metal framework in full-arch immediate loading rehabilitations of the maxilla - a cohort clinical study.

Frameworks made of carbon fibre-reinforced composites (CFRC) seem to be a viable alternative to traditional metal frameworks in implant prosthodontics. CFRC provide stiffness, rigidity and optimal biocompatibility. The aim of the present prospective study was to compare carbon fibre frameworks versus metal frameworks used to rigidly splint implants in full-arch immediate loading rehabilitations. Forty-two patients (test group) were rehabilitated with full-arch immediate loading rehabilitations of the upper jaw (total: 170 implants) following the Columbus Bridge Protocol with four to six implants with distal tilted implants. All patients were treated with resin screw-retained full-arch prostheses endowed with carbon fibre frameworks. The mean follow-up was 22 months (range: 18-24). Differences in the absolute change of bone resorption over time between the two implant sides (mesial and distal) were assessed performing a Mann-Whitney U-test. The outcomes were statistically compared with those of patients rehabilitated following the same protocol but using metal frameworks (control group: 34 patients with 163 implants - data reported in Tealdo, Menini, Bevilacqua, Pera, Pesce, Signori, Pera, Int J Prosthodont, 27, 2014, 207). Ten implants failed in the control group (6·1%); none failed in the test group (P = 0·002). A statistically significant difference in the absolute change of bone resorption around the implants was found between the two groups (P = 0·004), with greater mean peri-implant bone resorption in the control group (1 mm) compared to the test group (0·8 mm). Carbon fibre frameworks may be considered as a viable alternative to the metal ones and showed less marginal bone loss around implants and a greater implant survival rate during the observation period.

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

OBJECTIVES: 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 5.5 years. MATERIAL AND METHODS: 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 5.5 years 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. RESULTS: After simulated fatigue, the retention for both systems at both set-ups reduced. The Locator system reduced from 108.9 to 20.2 N in the parallel set-up and from 82.3 to 17.3 N in the divergent set-up. For the ball system, the retention reduced from 56.2 to 46 N when parallel and from 45.7 to 40.7 N when divergent. CONCLUSION: 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.