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Copyright of Brazilian Dental Science is the property of Brazilian Dental Science Journal-ICT-UNESP and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Objectives The aim of the present study was to evaluate the retention and loss of retention after fatigue testing at different time intervals between two types of bar clip materials (digitally designed PEEK bar clip and regular Nylon bar clip). Materials and methods An epoxy model was constructed for a completely edentulous mandible. Two implants were placed according to prosthetically driven implant placement by a computer-guided surgical stent. Bar clips were digitally designed, 3D printed, and pressed into Poly Ether Ether Ketone (PEEK). Pick up of PEEK and nylon clips was performed on the dentures fitting surface using self-cured acrylic resin. Each study group was subjected to an insertion and removal fatigue test simulating 3 years of patient usage. Retention values were recorded using the universal testing machine at initial retention and after 1, 2, and 3 years of simulated usage. For proper sample sizing, 24 models and dentures (12 for each group) were used. An independent sample t-test and repeated measures analysis of variance were used to compare the data. Results There were statistically significant differences in retention between the PEEK and nylon bar clips at the beginning of the experiment (p = 0.000*). But after 3 years of simulated use, there was no significant difference in retention between the test groups (p = 0.055, NS). After 3 years of simulated use, the retention of PEEK clips decreased by − 58.66% recording 17.37 ± 1.07 N, while the retention of nylon clip increased by + 2.99% recording 16.56 ± 0.88 N. Conclusion The digitally designed PEEK clip showed comparable retention results to the nylon clip after 3 years of simulated use. Clinical relevance Maintenance of bar attachment with PEEK clip offers a clinical solution after the wear of normal plastic clips, which is a cheap solution that is easily fabricated and picked up into the denture. Digital fabricated PEEK bar retentive inserts can be used in cases of bar attachment wear.

The prosthetic treatment of a maxillary edentulism bordered by an incisor is a source of therapeutic difficulties due to its particular topography generating biomechanical and aesthetic problems. We here report, the keys to the success of prosthetic rehabilitation using complexe combine prosthesis to meet the aesthetic and functional requirements of a patient with this particular edentulism. The clinical case has been presented according to a didactic approach to highlight the therapeutic difficulties and the different prosthetic treatment sequences to be respected to guarantee the integration of the prosthesis and its longevity. [ABSTRACT FROM AUTHOR]

Purpose: Implant-retained mandibular overdentures are a proven treatment modality for edentulous patients. Low-profile stud attachments may allow divergence between the abutments up to 40 degrees. The purpose of this study was to investigate load transfer characteristics of various locations and nylon male configurations of low-profile stud attachment–retained overdentures. Materials and Methods: Three tapered dental implants were placed into three photoelastic mandibular models. The center implants were placed vertically onto the midline, and the distal implants were inclined 20 degrees corresponding to centralized implants. Three different distances (11, 18, and 25 mm) between the centralized and the distal implants were set on the models. Low-profile stud attachment (Locator)–retained mandibular overdentures were fabricated for each photoelastic model. Five different nylon male configurations of this stud attachment were established. The load transfer characteristics of the configurations were tested using a circular polariscope. Results: The observed stress levels for the tested configurations were moderate except for group 25C (photoelastic model with 25-mm interimplant distances and clear nylon male), which illustrated a high stress level. For the 11-mm photoelastic model, little or no discernible stress was noted around the dental implants for group 11R (red nylon male), group 11G (green nylon male), and configurations of clear and red or green nylon males (group 11CR [clear and red nylon males] and group 11CG [clear and green nylon males]). Conclusion: The applied loads were distributed to the supported dental implants and denture-bearing areas for tested designs. Equitable load distribution and less stress may be gathered using nylon males for angulated implants (red and green) when dental implants are placed inclined. [ABSTRACT FROM AUTHOR]

The provision of removable partial dentures (RPDs) is an important skill for practitioners and it can often be challenging to make a successful prosthesis which the patient finds satisfactory. This three-part series has been designed to provide an overview of the clinical management of patients requiring RPDs. This final part describes more complex techniques that may be faced by dentists with additional training or experience in fixed and removable prosthodontics. These scenarios include the use of precision attachments to provide additional retention for an RPD, swinglock dentures to aid retention in cases with unfavourable tooth or alveolar undercuts, and sectional dentures for patients with challenging paths of insertion. For each clinical technique, the advantages, disadvantages and indications are summarised., (© 2024. The Author(s), under exclusive licence to the British Dental Association.)

Objective: This review is to compare patient-satisfaction with ball-type overdenture attachment systems with others attachment systems. Material and methods: This study was registered in PROSPERO (CRD42018097234) and adheres the PRISMA guidelines. Electronic searches on PubMed/MEDLINE, Scopus, Cochrane, and Web of Science databases for published articles were performed before October 2020. The PICO question was: “Do patients with a ball-type overdenture retention system have greater satisfaction, when compared to other attachment systems?” The evaluation of risk of bias was performed using the Cochrane risk of bias tool. Results: After searching the databases, seven articles were selected out of a total of 2583. A total of 312 implants were placed in 139 patients, with a mean age of 65.9 years. The risk of bias in the included studies varied according to the different domains in a risk of uncertain bias or low bias risk. No difference was found between the ball attachment systems and the others systems, with respect to patient-satisfaction. The meta-analysis revealed no statistically significant difference between the ball systems and another systems (P = 0.11; MD: 10.90; 95% CI: −2.55 to 24.35). Conclusions: Regarding patient general satisfaction, it was not possible to determine differences between the ball system and another types of attachment system for overdenture. The ball-type system was statistically superior only to the magnet system.

Objectives: The aim of the present study was to evaluate the retention and loss of retention after fatigue testing at different time intervals between two types of bar clip materials (digitally designed PEEK bar clip and regular Nylon bar clip). Materials and methods: An epoxy model was constructed for a completely edentulous mandible. Two implants were placed according to prosthetically driven implant placement by a computer-guided surgical stent. Bar clips were digitally designed, 3D printed, and pressed into Poly Ether Ether Ketone (PEEK). Pick up of PEEK and nylon clips was performed on the dentures fitting surface using self-cured acrylic resin. Each study group was subjected to an insertion and removal fatigue test simulating 3 years of patient usage. Retention values were recorded using the universal testing machine at initial retention and after 1, 2, and 3 years of simulated usage. For proper sample sizing, 24 models and dentures (12 for each group) were used. An independent sample t-test and repeated measures analysis of variance were used to compare the data. Results: There were statistically significant differences in retention between the PEEK and nylon bar clips at the beginning of the experiment (p = 0.000*). But after 3 years of simulated use, there was no significant difference in retention between the test groups (p = 0.055, NS). After 3 years of simulated use, the retention of PEEK clips decreased by − 58.66% recording 17.37 ± 1.07 N, while the retention of nylon clip increased by + 2.99% recording 16.56 ± 0.88 N. Conclusion: The digitally designed PEEK clip showed comparable retention results to the nylon clip after 3 years of simulated use. Clinical relevance: Maintenance of bar attachment with PEEK clip offers a clinical solution after the wear of normal plastic clips, which is a cheap solution that is easily fabricated and picked up into the denture. Digital fabricated PEEK bar retentive inserts can be used in cases of bar attachment wear. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the published literature on tooth-tissue supported removable partial dentures (RPDs) and determine the attachment system that provides the best clinical outcome., Materials and Methods: A comprehensive search of studies published up to November 2021 was performed in the PubMed/MEDLINE, Web of Science, and Cochrane Library databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The study protocol was approved and was registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42021268449). The PICO question was, 'What is the best attachment system used in Kennedy class I and II removable partial dentures?', Results: The search identified 871 articles, of which 21 met the inclusion criteria. The evaluation period in the studies ranged from 3 to 282 months. A total of 1,357 patients were included, of which 526 used prostheses with attachments. The mini SG attachment (extracoronal) was the most commonly used attachment, and the survival rate ranged from 37% to 98.1% in 10 studies, with no significant differences between the systems. Among the 10 studies selected for quantitative analysis, the meta-analysis revealed an overall failure rate of 16.6% (95% CI: 10.4% to 25.4%) and heterogeneity of I² = 65.725 (q value: 26.258, P = .002)., Conclusions: Clinical studies comparing different attachment systems for rehabilitation are lacking. Our findings suggest that attachment-retained RPDs have good retention and better esthetics than conventional RPDs, and the extracoronal attachment system is the most viable choice for treatment at the free end.

While nickel-titanium (NiTi) is the primary shape memory alloy (SMA) used in endodontic instruments, restorative dental components so far have not been fabricated from SMAs. The flexibility of these materials may solve problems in implant prosthodontics resulting from non-parallel implant positions and transfer inaccuracies. Based on a prototype of a novel attachment system for implant overdentures, a finite element model was created and used for studying different loading situations and design parameters followed by numerical analysis aided design optimization. The results revealed that the basic design of the attachment is capable of compensating misalignments of supporting implants as well as transfer inaccuracies of a clinically relevant magnitude by accommodating the large deformations induced under masticatory loading upon martensitic phase transformation at almost constant stress. The application of NiTi resulted in the reduction of the reaction forces recorded in the surrounding of the supporting implant, as well, the reaction forces between male and female parts of the attachment system could be reduced which will minimize wear phenomena and subsequent maintenance costs. These effects were seen to be enhanced in the optimized design.

This review is to compare patient-satisfaction with ball-type overdenture attachment systems with others attachment systems. This study was registered in PROSPERO (CRD42018097234) and adheres the PRISMA guidelines. Electronic searches on PubMed/MEDLINE, Scopus, Cochrane, and Web of Science databases for published articles were performed before October 2020. The PICO question was: "Do patients with a ball-type overdenture retention system have greater satisfaction, when compared to other attachment systems?" The evaluation of risk of bias was performed using the Cochrane risk of bias tool. After searching the databases, seven articles were selected out of a total of 2583. A total of 312 implants were placed in 139 patients, with a mean age of 65.9 years. The risk of bias in the included studies varied according to the different domains in a risk of uncertain bias or low bias risk. No difference was found between the ball attachment systems and the others systems, with respect to patient-satisfaction. The meta-analysis revealed no statistically significant difference between the ball systems and another systems (P = 0.11; MD: 10.90; 95% CI: −2.55 to 24.35). Regarding patient general satisfaction, it was not possible to determine differences between the ball system and another types of attachment system for overdenture. The ball-type system was statistically superior only to the magnet system. [ABSTRACT FROM AUTHOR]

Background: Distal edentulous spaces can be challenging when rehabilitation with dental implants is limited. Attachment-retained removable partial dentures [RPD] work as a therapy that can compensate rotational movements and reduce the number of abutments. Case description: This clinical report addresses indications, selection and procedures for the rehabilitation of a partially edentulous maxilla, involving laminate veneers, fixed and removable prostheses. Practical implications: Attachment-retained RPDs provide sufficient retention and improved aesthetics compared to clasp-retained partial dentures. Careful aesthetic and functional planning and periodic follow-up are essential for patients' satisfaction. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare the retention and stability of the Nobel Biocare standard ball (NBS), Nobel Biocare 2.25-mm-diameter ball (NB2), Zest Anchor (ZA), Zest Anchor Advanced Generation (ZAAG), Stern gold ERA orange (SEO), and Sterngold ERA white (SEW) attachments on an implant-retained overdenture model. Materials and Methods: The attachments were tested using 2 permanently placed Brånemark System implants on a test model that was attached to an Instron machine (crosshead speed 50.8 mm/minute). Each attachment had one part embedded in a denture-like housing and the other part screwed into the implants. Dislodging tensile forces were applied to the housings in 3 directions simulating function: vertical, oblique, and anterior-posterior. Eight tests were done in 3 directions with 6 samples of each attachment. The dislodging forces generated measurements of the peak load (maximum dislodging force). A 1-way analysis of variance followed by the Tukey studentized range test was used to determine groups that were significantly different. All tests for significance were carried out at the .05 level of significance. Results: Results showed the ZAAG attachment to be the most retentive for the peak load measurement when subjected to vertically directed forces, with mean values and standard deviations of 37.2 ± 5.5 N. The next most retentive attachment was the NBS, followed by the SEO, NB2, SEW, and ZA. For obliquely directed forces, the ZAAG attachment was the most retentive, with mean values and standard deviations of 27.2 ± 4.2 N. The next most retentive was the NBS, followed by the NB2, SEO, ZA, and SEW. For anterior-posteriorly directed forces, results showed the NBS had the highest measured retentive force, with mean values and standard deviations of 34.6 ± 18.8 N, but this was not statistically different from the NB2 and ZAAG; this was followed by the SEO, SEW, and ZA. Discussion: There has been a marked resurgence in the treatment of patients with overdentures using implant attachments as retentive devices. The maximum force developed (a measure of retention) as the implant stud attachments were resisting removal from the implant abutments was determined. Conclusions: Based on the present study, the clinician may be able to make empirical decisions on attachment selection, depending on the amount of retention desired and the specific clinical situation. [ABSTRACT FROM AUTHOR]

Objective: Implant-supported-overdentures, instead of conventional complete dentures, are frequently recommended to rehabilitate patients having edentulous mandible. The aim of this study was to evaluate the stress distribution characteristics of mandibular implant-supported overdentures with four different bar attachment designs. Materials and Method: A photoelastic mandibular model with three implants (3.75 mm - 13 mm) placed at the interforaminal region was generated from a cast of an edentulous mandible. Four mandibular bar overdenture designs were fabricated: bar-clip, bar-galvano, bar-locator, and bar-ceka. Axial vertical loads (135 N) were applied to the central fossa of the right first molar area for each overdenture design. Stress concentrations were recorded photographically and analyzed visually. Results: The tested bar attachment designs revealed low and moderate stress levels. The lowest stress was observed with the bar-clip design, followed by bar-locator, bar-ceka, and bar-galvano designs. Conclusion: The loads were distributed to all of the implants. Studied designs experienced moderate stress levels around the loaded side implant. Bars with distally placed stud attachments and surface treatment with electroforming seems to increase stress levels around the implants.

Purpose: The purpose of the study was to analyze and compare retention characteristics of different stud attachments including a standard and two low profile attachments on two implant embedded test models. Methods: Three different stud attachment systems (Ball attachment and two different low profile stud attachments - Equator and Locator) were used in this study. Two dental implants were placed vertically into a custom-made acrylic resin block within a 22 mm distance. Strong and soft nylon inserts of each attachment system were tested using cyclic dislodgement test for 24 months simulation. Maximum forces during the test were recorded and 10 consecutive data at baseline, 1st to 24th months were analyzed. Repeated measures ANOVA and post-hoc Tukey's test ( p < 0.05) were used for statistical analysis. Results: Retentive forces of the tested attachments varied from 30.7 to 93.75 N at the baseline. The highest initial mean retention (93.75 N) was observed in Group LC (locator attachment with clear nylon inserts) and the lowest initial mean retention (30.7 N) was detected in both Group BO (ball attachment with orange nylon inserts) and Group EY (equator with yellow nylon inserts). After the 24 months simulation, locator groups illustrated more light retention than other tested attachment systems. Conclusions: All tested attachment systems showed a significant decrease in retention value at the end of the simulated period. The locator attachment had significantly higher reduction in retention values compared to other low profile stud attachment equator and ball attachment. [ABSTRACT FROM AUTHOR]

Summary: 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. [ABSTRACT FROM AUTHOR]

Objective. The aim of this survey was to record removable partial denture (RPD) retentive elements and abutment teeth in partially edentulous patients, identified in commercial laboratories in Athens, Greece. Material and Methods. 628 master casts with the corresponding cast metal frameworks used in the construction of RPDs were evaluated. Casts were photographed to identify the number and position of existing teeth, the partial edentulism class and the retentive elements. Prevalence tables and the x2 test were used for the statistical analysis of the collected data (α=.05). Results. There were 276 maxillary (43.9%) and 352 (56.1%) mandibular casts. Maxillary edentulism entailed almost a total absence of right third molars in 96.7% and left third molars 96.0% of casts, with lower rates for the first and second molars. Edentulism in the posterior mandible presented a similar pattern. The most profound findings concerning retentive elements were: 91.9% of the retainers used were clasps and the remaining 8.1% were attachments. Of the clasps used, 48.9% were of the Roach Τ type, a finding more common in Kennedy Class I as compared to other Kennedy Classes (p

The purpose of this study was to evaluate the change in the retentive forces of four different titanium-based implant attachment systems during the simulation of insert−removal cycles in an artificial oral environment. Five types of titanium-based dental implant attachment systems (Locator, Kerator, O-ring, EZ-Lock, and Magnetic) were studied (n = 10). The specimens underwent insert−removal cycles in artificial saliva, and the retentive force was measured following 0, 750, 1500, and 2250 cycles. Significant retention loss was observed in all attachment systems, except the magnetic attachments, upon completion of 2250 insertion and removal cycles, compared to the initial retentive force (p < 0.05). A comparison of the initial retentive forces revealed the highest value for Locator, followed by the Kerator, O-ring, EZ-Lock, and Magnetic attachments. Furthermore, Kerator demonstrated the highest retentive loss, followed by Locator, O-ring, EZ-Lock, and Magnetic attachments after 2250 cycles (p < 0.05). In addition, the Locator and Kerator systems revealed significant decrease in retentive forces at all measurement points (p < 0.05). The retention force according to the insert−removal cycles were significantly different according to the types of dental implant attachment systems.

Copyright of Acta Odontologica Turcica is the property of Acta Odontologica Turcica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: The present study evaluated the effect of bar and ball attachment designs on retention and stability of a mandibular overdenture supported by four implants. Methods: An edentulous mandibular acrylic resin model with four implants in the anterior part of the ridge (A, B, D and E) was fabricated. A metal framework simulating the overdenture was also fabricated. Totally, 30 overdentures were divided into three groups based on the attachment design; BL: Four ball attachments in A, B, D and E positions; BB: One bar attachment between B and D positions and two ball attachments at positions A and E; BR: Bar attachments between the positions A, B, D and E with two posterior extensions. To evaluate the retention and stability of the overdenture, tensile dislodging forces were applied in three directions of vertical, oblique and anterior-posterior by a universal testing machine. One-way ANOVA and Tukey's HSD test were performed to analyze the data. All tests were carried out at 0.05 level of significance. Results: There were statistically significant differences between the groups in the peak load (P<0.001). The peak load values for vertical, oblique and anterior-posterior dislodging forces were the highest for BL with 49.38 ° 2.19 N, 52.19 ° 1.44 N, and 49.03 ° 5.89 N, respectively, while these values were the lowest for BR with 29.78 ° 2.52 N, 12.10 ° 0.45 N, and 6.26 ° 0.45 N, respectively. Conclusion: The attachment designs affected the retention and stability of mandibular implant-supported overdentures. [ABSTRACT FROM AUTHOR]

OBJECTIVES: The wear of telescopic crowns is a common problem often reducing the patient's satisfaction with the denture and resulting in a renewal of the denture. The study aims to compare the wear behavior of conical crowns using electroplated copings (group E ) with standard telescopic crowns with cast female parts (group C). MATERIAL AND METHODS: 10 conical crowns were milled for each group of a cast gold alloy. The specimen of group E had a conicity of 2º. The cast secondary crowns of group C had a 0º design. The electroplated coping was established by direct electroforming. An apparatus accomplishing 10,000 wear cycles performed the wear test. The retentive forces and the correlating distance during insertion and separation were measured. The wear test was separated in a start phase, an initial wear phase and the long term wear period. The retention force value and the force-distance integral of the first 0.33 mm of each cycle were calculated. RESULTS: The retentive forces were significantly higher for group E and the integrals were significantly lower for this group except the integral at cycle 10,000. The changes of retention force and integral did not differ significantly between both groups in all phases. The change of the integrals as well as the integral at the particular cycles showed higher interquartile distances for group C. CONCLUSIONS: Within the limitations of this study the tested conical crowns showed clinically acceptable retentive properties. The values reached a range comparable to retentive elements tested in recent literature. The values of group C showed higher ranges. The force measured for group E was significantly higher than for group C but the integrals showed an opposite tendency. The results indicate that an exclusive analysis of the force is not sufficient as the integral is not equivalent to the force although it describes the retentive property of the system in a better way than the force over a distance is described. Both systems seem to be suitable for clinical practice.

Patients who underwent resection of maxilla due to benign or malignant tumor, or accident will have defect in palatal area. They get retention, support and stability from remaining tissues which are hardly optimal. The advantage of swing-lock attachment design is having multiple contacts on labial and lingual side of the abutment teeth by retentive strut and palatal bracing component. Because the force is distributed equally to abutment teeth, abutment teeth of poor prognosis can be benefited from it. It is also more advantageous to cover soft tissue defects which are hard to reach with conventional prosthesis. A 56-year-old female patient who had undergone a maxillectomy due to malignant melanoma complaining of loose and unstable surgical obturator. Surveyed crowns were placed on #12, 26, and 27. Teeth #11, 21, 22, and 23 had lingual rest seat and #24 had mesial rest seat to improve stability and support of the obturator. This clinical report presents the prosthetic management of a patient treated with obturator on the maxilla using swing-lock attachment to the remaining teeth. [ABSTRACT FROM AUTHOR]

O objetivo deste trabalho foi avaliar e comparar a capacidade retentiva entre dois sistemas O-ring e O-SO (Grupo I) e dois sistemas ERA - cápsulas de retenção cinza e brancas - (Grupo II), em função simulada, com ciclos de inserção e remoção, do início, 6 meses, 1, 2, 3, 4 e 5 anos depois. Dois implantes do tipo Brånemark foram fixados em duas bases metálicas trapezoidais, sendo os testes de inserção e remoção feitos numa máquina de costura ajustada para este propósito, usando um sistema de correias e polias, movendo um virabrequim. Uma platina de delineador foi usada para fixação dos corpos de prova às bases metálicas na máquina de costura. Os testes de resistência ao movimento axial das cápsulas por tensão foram feitos numa máquina de ensaios universal em períodos de tempo pré-estabelecidos, antes e após o término do ciclo na máquina de costura. Baseado nos resultados, esse estudo pôde concluir que houve perda de retenção de todos os sistemas testados, porém o sistema ERA apresentou, desde o início, maior retenção quando comparado aos outros sistemas e a cápsula cinza mostrou o melhor resultado no final da simulação.The aim of this study was to evaluate and compare the retentive capacity between two O-ring and O-SO system (Group I), and two ERA system types - white and gray retention caps - (Group II), respectively, in simulated function in database, 6 months, 1, 2, 3, 4, and 5 years later, with insertion and removal cycles. Two Brånemark implants were fixed in two trapezoidal metallic bases for the tests. Removal and insertion tests were done in a sewing machine, adjusted for this purpose using a belt and a pulley system, moving a steel crankshaft. A delineator platinum hold was used for body trial fixation to the metallic base of the sewing machine. Resistance test to axial movement of the caps by tension was done in a Universal test machine in an established period of time, before and after the cycle accomplishments in the adapted sewing machine. Based on the results, this study concludes that all the attachment systems tested showed retention loss during the experiment; the ERA system showed, since the beginning, higher retention compared to the other systems and the gray colored attachment showed the best result in the end of the simulated use test.

Copyright of Turkiye Klinikleri Journal of Dental Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Stomatologica Croatica is the property of Acta Stomatologica Croatica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Stomatologica Croatica is the property of Acta Stomatologica Croatica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: Retention and resistance of the implant-tissue supported overdenture may be affected by the type of attachment. The aim of this research was to compare the retention and resistance of Nobel Biocare Ball (NBB), Nobel Biocare Bar and Clip (NBBC) and Sterngold ERA Red (ERAR) attachments on an implant-tissue supported overdenture model. Materials and Methods: The attachment samples were divided into 3 groups of NBB, NBBC, and ERAR (5 samples in each group). Two parallel Nobel Biocare Branemark implants were placed symmetrically at the symphysis region of a mandibular test model. A metallic overdenture was fabricated precisely adapted to the model and attached to a Zwick testing machine (crosshead speed of 51 mm/min). Dislodging tensile forces were applied in three vertical, oblique, anterior-posterior directions and two situations, at the beginning and after 100 times of insertion/removal of the overdenture, for each sample. The maximum dislodging force was measured. A One-way ANOVA test was employed followed by Tukey's test. Results: ERAR was the most retentive and resistant in both situations. NBB and NBBC showed the same anterior-posterior resistance at the beginning. All test groups represented a large amount of retention and resistance loss after the insertion/removal of the overdenture, while NBBC showed a higher loss of anterior-posterior resistance than NB. Conclusion: A highest level of retention and resistance was seen in ERAR. The retention and resistance were affected by the wear of attachments.

Copyright of Turkiye Klinikleri Journal of Dental Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The degree of retention for overdenture attachments depends on design, location, and alignment of supporting dental implants and the type of attachments. The aim of this study was to evaluate the retention of an implant-supported overdenture with different attachment designs. An overdenture was made on an edentulous mandibular model with 2 ITI implants (4.1 x 10 mm) in the symphyseal region. Five specimens of 8 attachment designs with corresponding abutments and superstructures were used: ITI regular Dolder bar with 1 metal clip, ITI regular Dolder bar with cantilever and 3 metal clips, Hader bar with 1 plastic clip, Hader bar with cantilever and 3 plastic clips, Sphero block abutment with Rhein plastic caps (green, white, and pink), and retentive anchor with ITI elliptical matrix. The attachments' housings were interchangeable and fixed into the overdenture through nut and screw. The overdenture attachments were subjected to 8 consecutive pulls on a universal testing machine with a crosshead speed of 50.8 mm/min in the vertical and posteroanterior directions. Analysis of variance and Duncan tests were used to determine differences between mean retention values (α = .05). The highest average value retention was recorded for the ITI Dolder bar with cantilever and 3 metal clips in both the vertical and posteroanterior directions, respectively (P < .05). The Rhein pink caps had the lowest retention in the posteroanterior direction (P < .05). Retention decreased over the course of consecutive pulls for all attachments in both directions. The type, number, and placement of attachments affect the retention of implant-supported mandibular overdentures. [ABSTRACT FROM AUTHOR]

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The aim of this study was to determine the values of retentive forces of double crowns. The effect of the abutment height, the material of the inner crown, and the taper were evaluated. Sixty inner crowns each were fabricated from zirconia and a gold alloy having three different abutment heights (5, 7, and 9 mm) and two different tapers (0° and 2°). All outer crowns were made with an electroforming system. The removal test was performed by a standardized setup using a universal testing machine at a crosshead speed of 1,000 mm min−1. Ten separation cycles were performed of each specimen, and the mean was imported into a statistical program. The retention forces were in the range of 0.37 and 2.65 N. The abutment height ( p < 0.001), the material of the inner crown ( p = 0.035), and the taper ( p < 0.001) showed statistical influence on the retention force in the two-way ANOVA. Zirconia primary crowns performed better than gold alloy in the 0° group, especially with short abutments. However, a taper of 0° and short abutments have clinical drawbacks that were not evaluated in this study. In situations with long abutment teeth and a 2° taper zirconia is an alternative to gold alloy primary crowns. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to evaluate the retention force of an O-ring attachment system in different inclinations to the ideal path of insertion, using devices to compensate angulations. Material and methods: Two implants were inserted into an aluminum base, and ball attachments were screwed to implants. Cylinders with O-rings were placed on ball attachments and connected to the test device using positioners to compensate implant angulations (0°, 7°, and 14°). Plexiglass bases were used to simulate implant angulations. The base and the test device were positioned in a testing apparatus, which simulated insertion/removal of an overdenture. A total of 2900 cycles, simulating 2 years of overdenture use, were performed and 36 O-rings were tested. The force required for each cycle was recorded with computer software. Longitudinal sections of ball attachment–positioner–cylinder with O-rings of each angulation were obtained to analyze the relationship among them, and O-ring sections tested in each angulation were compared with an unused counterpart. A mixed linear model was used to analyze the data, and the comparison was performed by orthogonal contrasts (α=0.05). Results: At 0°, the retention force decreased significantly over time, and the retention force was significantly different in all comparisons, except from 12 to 18 months. When the implants were positioned at 7°, the retention force was statistically different at 0 and 24 months. At 14°, significant differences were found from 6 and 12 to 24 months. Conclusions: Within the limitations of this study, it was concluded that O-rings for implant/attachments perpendicular to the occlusal plane were adequately retentive over the first year and that the retentive capacity of O-ring was affected by implant inclinations despite the proposed positioners. [ABSTRACT FROM AUTHOR]

A shortened dental arch (SDA) is an established treatment concept for patients with missing molars. However, little is known regarding long-term course of oral health-related quality of life (OHRQoL) in patients with SDA and the benefits from replacement of missing molars. Purpose of this multi-center randomized clinical trial was to assess OHRQoL over a period of 15 years in patients with molar replacement by a removable partial denture (RPD) compared to patients with a restored SDA without molar replacement. Patients at least 35 years of age with all molars missing in 1 jaw and at least the canine and one premolar present on each side were included. Patients received either a precision attachment-retained, RPD for replacement of missing molars (n = 79), or the dental arch ended with the second premolar (SDA) that had to be present or replaced by a cantilever fixed dental prosthesis (n = 71). Follow-up examinations continued for 15 years. OHRQoL was assessed with the 49-item Oral Health Impact Profile (OHIP). OHIP summary and dimension scores were longitudinally modeled in the statistical analyses to assess course of OHRQoL over time applying an intention-to-treat approach. In addition, scores for the OHRQoL dimensions Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact were analyzed. After an initial improvement in OHRQoL indicated by a mean decrease of 20.0 OHIP points with an effect size of 0.61 in the entire study population, OHRQoL stayed relatively constant over the entire follow-up period. Assuming a constant time and treatment effects over the study period, OHRQoL did not differ statistically significant between the 2 treatments (0.4 OHIP points; 95%-CI: 7.1 - 6.2). OHRQoL after treatment did not change notably over 15 years and was statistically nonsignificant as well (P =.872). Similar findings were observed in all 4 OHRQoL dimensions. In patients, missing all molars in one jaw OHRQoL improved providing RPD or restoring SDA to a clinically relevant degree. Treatment-related improvement remained mostly stable over a period of at least 15 years. Therefore, patients can be informed that both treatment concepts are equivalent concerning long-term OHRQoL. Accordingly, patients' preferences regarding treatment options should be granted priority in treatment decision making with the SDA treatment option being the default. [Display omitted] [ABSTRACT FROM AUTHOR]