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Locator retained maxillary overdenture. (A) Locator abutments screwed in place on the model. (B) Fitting surface of maxillary overdenture with nylon inserts in place.
Source publication
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 connec...
Context in source publication
Context 1
... metal hooks (loops) were attached to the metal framework at the canine and second molar areas bilaterally. 19,27 The experimental overdenture was connected to the implant analogs using either O-ring (group I , Fig 1) or Locator (group II , Fig 2) attachments. Locators (group II) were divided into three subgroups according the type of retention of the patrix nylon insert: group IIa (blue insert, Locator extra-light retention), group IIb (pink insert, Locator light retention), and group IIc (transparent insert, Locator medium retention). ...
Similar publications
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) att...
Objective: Stress analysis and retention evaluation of implant-retained mandibular complete overdenture with different clip materials and distributions. Methods: This in-vitro study was conducted over implants retained mandibular complete overdenture (all-on-4 concept) using BIOHPP bar attachments constructed using 3 D printing with different clip...
The resistance of the periimplant tissues to inflammation is evidently much lower with the implant than that of natural teeth. In order to maintain periimplant health, and prevent implant failure, it is important to understand the relationship between abutment surface characteristics and plaque attachment. The aim of this study is to assess whether...
Citations
... Due to wear over time, loss of attachment retention is the most frequent issue with implant-retained overdentures [10][11][12][13]. According to Lambrechts et al., [14] wear is a complicated phenomenon that is the end consequence of numerous interconnected processes acting together. ...
... Wear frequently occurs within the first 12 months of use, necessitating more frequent maintenance of the attachments [8,9,11]. For this reason, the current study was carried out after 1000 cycles of removal and insertion, which correspond to one year of use, to mimic the clinical wear patterns of attachment systems [29,28]. ...
Background
Attachment material is one of the contributing factors to the degree of wear of the attachment components in mandibular implant-retained overdentures. The purpose of this in vitro study was to compare the wear behavior of 2 different attachment systems of dissimilar materials in mandibular implant-retained overdentures by qualitative and quantitative methods.
Methods
Two attachment systems of different materials were utilized (n = 16); Titach (Dental Evolutions Inc, Beverly Hills, CA, USA) with a titanium-to-titanium interface and Locator R-Tx (Zest Anchors Inc, Escondido, CA, USA) with a titanium-to-nylon interface. One thousand cycles of overdenture insertion and removal simulating 1-year clinical use were performed. All matrices were removed from the overdentures and all patrices were unscrewed from the implants for wear assessment quantitively using a stereomicroscope and qualitatively using a scanning electron microscope. Data were analyzed by using an independent sample t test.
Results
After cyclic loading, stereomicroscopic findings showed that the Titach group had statistically significant higher wear value than the Locator R-Tx group (p < 0.001). Moreover, scanning electron microscopy images showed noticeable abrasion in Titach patrix at the area of highest convexity. However, the Locator R-Tx matrix displayed an apparent tear of rubber inserts.
Conclusions
Titach attachment with the titanium-to-titanium interface revealed more wear than Locator R-Tx attachment with the titanium-to-nylon interface. Thus, the type of attachment material influences the degree of wear of the attachment components.
... For all groups, experimental overdentures that had four metal hooks attached to the canine and second molar areas were constructed. [34][35][36] Each overdenture consisted of an acrylic bite block without denture teeth. ...
Purpose:
To compare the axial and nonaxial retention forces of different milled bar attachment designs for maxillary implant overdentures.
Materials and methods:
Four implants were placed in the canine and second premolar areas of an edentulous maxillary ridge model and connected to a cobalt-chromium milled bar either with or without Locator attachments. According to the type of bar and overlying housing, the following groups (n = 10 each) were investigated: group 1 (MWM) = milled bar without attachments and metal housing; group 2 (MWP) = milled bar without attachments and PEEK housing; group 3 (MAM) = milled bar with Locator attachments and metal housing; and group 4 (MAP) = milled bar with Locator attachments and PEEK housing. Axial and nonaxial (anterior, posterior, and lateral) retention forces were measured both at baseline and after wear simulation, then compared between groups and dislodging directions.
Results:
MAM showed the highest axial (53.20 ± 2.28 N) and nonaxial (anterior [33.80 ± 1.48 N], posterior [37.60 ± 2.07 N], and lateral [34.40 ± 1.67 N]) retention forces at baseline, followed by MAP, then MWM, and MWP (P < .001). MAP showed the highest axial (42.80 ± 2.28 N) and nonaxial (anterior [24.00 ± 1.58 N], posterior [29.40 ± 2.07 N], and lateral [27.80 ± 1.64 N]) retention forces after wear simulation, followed by MAM, then MWP, and finally MWM (P < .001). MAM showed the highest axial (25.25 ± 2.45 N) and nonaxial (anterior [28.29 ± 4.03 N], posterior [24.40 ± 3.25 N], and lateral [25.55 ± 1.65 N]) retention loss, followed by MWM, then MAP, and finally MWP (P < .001). For all groups, the highest retention forces were noted with axial dislodging, followed by posterior dislodging, then lateral dislodging, and finally vertical dislodging (P < .001).
Conclusion:
Milled bars with PEEK housings and Locator attachments for maxillary implant overdentures were associated with the highest axial and nonaxial retention forces after wear simulation, while milled bars with metal housing and no attachments showed the lowest forces. Milled bars with metal housing and attachments showed the highest retention loss, while milled bars with PEEK housing with no attachments showed retention gain.
... Overdenture may contact with the mucosa and so may affect the way of overdenture disconnection from attachments during anterior, posterior and lateral dislodging. [10][11] the implants in Canine and second premolar areas were chosen to provide quadrilateral support compared to the linear designs at the anterior area of maxilla. The premolar area has been more favorable in stress transfer to the underlying bone than a concentrated of implants in the anterior area. ...
... Ball attachment is one of the most popular attachment techniques for implant-supported overdentures, and the majority of ball attachments rely on the O-Ring connector for optimal retention. [18] Although the O-Ring is a good attachment system, it has several flaws, such as diminishing its holding force with time (6-12 months). [19] While O-Ring attachments rely on the silicon ring's viscoelastic properties to obtain retention with ball attachment, [20] Molloplast-B, which has viscoelastic features as well, can also be used with ball attachment, especially because Molloplast-B keeps its viscoelastic capabilities for a long time. ...
Aim: The purpose of this study is to evaluate the retention effectiveness of Molloplast B as a female
attachment compared to O rings’ in implant supported overdentures.
Settings and Design: This systematic review and meta-analysis was evaluated using the Preferred Reporting
Items for Systematic Review and Meta-Analysis guidelines.
Materials and Methods: Sixteen female part models were divided into two groups: eight female parts made
with O ring (Group A) and eight female parts made with Molloplast B (Group B). All of the models were
soaked in artificial saliva for 24 h, then, their retention force was measured in Newton using a Universal
mechanical testing machine, initially, after 500, after 1000, and after 1500 of loading and dislodging cycles.
Statistical Analysis Used: The statistical analysis was conducted by using one way ANOVA test and Bonferroni
test. SPSS Software (SPSS, Version 27, IBM Co., Chicago, IL, USA).
Results: After 1500 loading and dislodging cycles, Group B has the highest mean retention force (4.09),
followed by Group A, which has a mean retention force of 3.73.
Conclusion: Molloplast B with a 2.7 mm diameter ball attachment lost the least amount of retention force
after 1500 loading and dislodging cycles.
... The addition of a 2 mm thick layer of autopolymerized silicone soft liner superficially to simulate the ridge mucosa may have had an additional influence on the retentive forces of the attachment systems. [13,17] Nonetheless, this current study has reported the retentive capacity of implant-supported overdentures in the vertical direction in two types of attachment systems both in the anterior and posterior regions, which is a significant merit to the study. ...
Aim:
This study aims to compare the retentive capacity of two attachment systems after manual thermocycling.
Settings and design:
In vitro study and Comparative trail.
Materials and methods:
An edentulous mandibular Polymethyl Methacrylate model was fabricated to receive the overdentures with the two attachment systems to be compared. Two dental implants were placed in the predetermined right and left mandibular canine regions of the model. A total number of eight overdentures, four per group, were fabricated over the two implants with two attachment systems to be compared; Bar and clip attachment system (Group-1) and Locator attachment system (Group-2). All the overdentures were subjected to 5000 alternating thermal cycles using manual thermocycling. Then the samples were subjected to 100 vertical pulls each in the anterior and posterior regions using a universal testing machine and the mean retentive forces were calculated for each sample in the anterior and posterior regions, respectively.
Results:
The mean retentive forces after 100 vertical pulls, were calculated and tabulated for each sample in the anterior and posterior regions separately. Then, the cumulative mean of the anterior and the posterior regions were calculated for each group. The cumulative mean retentive forces of both the attachment groups were-Group-1 (Bar and clip attachment system) = 27.87 N ± 4.01 and Group-2 (locator attachment system) = 18.85 N ± 2.50 with a P value of 0.021. This difference was found to be statistically significant.
Conclusion:
Within the limitations of the present in vitro study, the bar and clip attachment system offered better retention than the locator attachment system.
... Soft liner was used to simulate the mucosa because the nature of contact of overdenture base with the soft tissue mucosa differs from that with hard resin as the resiliency of soft tissue may increase the load on the attachments and hence affect their retentive values. Furthermore, because the denture base periphery may pivot on the soft liner, overdenture contact with the mucosa may alter the way attachments disconnect, particularly during non-axial dislodging (21,22) . lastly, the presence of undercut in the resin model may resist and prevent the dislodgement of the prosthesis. ...
... In agreement with this finding, Kleis et al. (29) concluded that Locator attachments lost 75.5% of their retention capacity over time because of wear of the patrix Locator part. Similarly, Turk et al. (30) reported that Locator attachments showed significant retention reduction after 100, 200, 300, 500, and 3000 cycles as compared with the previous cycle (22) . ...
... Both initial and post-load values were consistent among the tested groups, agreeing with a similar study. Maxillary overdenture retained by four MDIs with O-rings recorded more resistance towards posterior dislodgment, followed by lateral and anterior forces [38]. In the same way, forces that resisted posterior dislodgment in this study were higher than those that resisted anterior or lateral dislodgment for the three and four MDIs groups. ...
The rotational movement of mini dental implants (MDIs) overdenture disturbs the function of the prosthesis. Many dentists place more MDIs to improve the overdenture stability; however, the influence of the MDIs number and distribution on the overdenture resistance to para-axial dislodgment has not been investigated. Seven resin models simulating atrophic mandibles housed twenty MDIs placed according to seven arrangements. Acrylic overdentures were fabricated for each cast and were dislodged five times in lateral, anterior and posterior directions, and the peak load dislodgment was measured. Each overdenture underwent 540 axial removal/placement cycles. The para-axial dislodgments were measured again, and data were compared. Dislodgment force values were measured in all directions, and the data were analysed using analysis of variance ANOVA and post hoc (p < 0.05). After six months of simulated placement/removal, increasing the MDI number showed a difference in resistance to para-axial dislodgment. The distribution affected the resistance to dislodgment in some directions. The inter-implant distance of 27 mm provided better resistance to posterior dislodgment than placing two MDIs close together at 19 mm. The placement of three MDIs at any distribution showed no significant difference except for resistance to posterior dislodgment. FourMDIs placed at any distribution showed a significant difference in all groups in all tested directions. The resistance to the para-axial dislodgment of MDI overdenture could improve with the increasing MDIs number and careful planning of MDI distribution.
... 22 Furthermore, the low number of 50 connection and disconnection cycles omits to report on long-term repeatability of the retention forces. However, the current study has not aimed to prove long term stability of Orings as this has been extensively evaluated before, [14][15][16]23 This peer-reviewed, accepted manuscript will undergo final editing and production prior to publication in IJP. This peer-reviewed, accepted manuscript will undergo final editing and production prior to publication in IJP. ...
Purpose:
To analyze the influence of pristine matrix and O-ring dimensions on retention force and reproducibility in single one-piece mini dental implants (MDIs) with ball patrices under in vitro conditions.
Materials and methods:
Three different matrix and O-ring combinations (MH1-MH3) were evaluated (n = 50 per group) on 1.8-mm-diameter implants. The matrices were manually mounted on the implants and were subsequently removed in a vertical linear manner using a metal pin with two strain gauges, recording the maximum force during disconnection. After five disconnections, the O-rings were exchanged, and the mean retention force was calculated, resulting in 50 values for each matrix and O-ring combination. Mean retention forces, SDs, and 95% CI were calculated. Analysis of variance was used to test the global differences, and post hoc pairwise comparisons were subsequently applied. The level of significance was set to P < .05.
Results:
ANOVA (global P < .0001) and pairwise comparisons (all P < .0001) demonstrated statistically significant differences among the three different matrix and O-ring combinations, with mean values of 5.18 N (MH 1), 6.73 (MH 2), and 9.08 (MH 3). Within each combination, retention force variations of > 1 N could not be demonstrated; ie, by exchanging O-rings, a similar retention force can be reestablished.
Conclusion:
Matrix and O-ring dimensions have a significant influence on retention forces in one-piece MDIs. Pristine O-rings demonstrated highly reproducible initial retention forces in all matrices.
... Attachment systems were classified into splinted attachments as bars and non-splinted attachments as locators, ball attachments, magnets, and telescopic crowns (5) . The selection of a particular attachment for maxillary overdentures is dependent on the retention required, inter-arch distance, jaw anatomy, and patient compliance for recall to perform adequate maintenance (6) . Non-splinted attachments are considered more favorable since they are more economical, easier to clean, and less technique sensitive than splinted attachments (7) . ...
... Implant design and attachment type may affect the retention of maxillary implant-supported overdentures and consequently patient satisfaction. In reviewing the literature, few studies evaluated the retention of maxillary implant-supported overdenture with O-ring, Locator, and Hader bar attachments (6) . However, the retention of palateless maxillary implant-supported overdenture with locater and ready-made titanium telescopic attachment is not evaluated yet. ...
Objective: This study aims to evaluate the effect of two different implant designs (one-piece dental implant and two-piece dental implant) with attachment systems on retention value in implant-supported palate less maxillary overdenture. Methods: Two edentulous maxillary models were fabricated from cold-cure polymethyl methacrylate resin. Four implants were inserted for each model as follows: Model I (Four one-piece implants were inserted, two implants in the canine region and two implants in the second premolar region), while Model II (Four two-piece implants were inserted, two implants in the canine region and two implants in second premolar region). The maxillary denture was constructed over each model. In model I, four ready-made titanium telescopic attachments corresponding to implant abutments were embedded in the inner surface of the overdenture. In contrast, in model II, four locator attachments corresponding to implant abutments were embedded in the inner surface of the overdenture. Initial anterior, posterior, and central retention values of overdentures were recorded and compared with the retention after 540 and 1080 cycles of insertion and removal using a digital force gauge. Results: Statistical analysis revealed significant differences in the initial, secondary and tertiary retention values for anterior, posterior, and central retentions for both models (higher values were recorded before insertion cycles). The higher anterior and central retention values were recorded in Model II (44.93 and 25.9) N respectively, on the other hand, the higher posterior retention value was recorded for Model I 23.3N. Conclusions: The type of attachment affects the retention value of maxillary overdenture. Continuous insertion and removal of the prosthesis lead to a decrease in the retention values.
... On the other hand, very high retention forces may induce load on implants during overdenture dislodgement or when removing the overdenture 22 . Therefore, a compromise should be made between high retention force vs. peri-implant stress 22,23 Reviewing the literature, many invitro reports [24][25][26] evaluated the retention forces of maxillary implant overdenture attachments. Other invitro studies 27,28 investigated the effect of attachment type on periimplant stresses. ...
... This method ensures vertical dislodging of the overdenture as one unit without rotation. This method was designed and verified for accuracy in several previous in vitro studies for maxillary and mandibular overdentures [24][25][26]31,35,[37][38][39] . Vertical dislodging force was exerted at 50mm/min speed to simulate the velocity of overdenture removal from the tissue during chewing as reported in previous studies 37,40 . ...
