RESUMEN
PURPOSE@#The purpose of this study was to investigate changes in retention and wear pattern of Locator® and ADD-TOC attachments on a digital milled bar by performing chewing simulation and repeated insertion/removal of prostheses in fully edentulous models. @*MATERIALS AND METHODS@#Locator (Locator®; Zest Anchors Inc., Escondido, CA, USA) was selected as the control group and ADD-TOC (ADDTOC; PNUAdd Co., Ltd., Busan, Republic of Korea) as the experimental group. A CAD-CAM milled bar was mounted on a master model and 3 threaded holes for connecting a bar attachment was formed using a tap. Locator and ADD-TOC attachments were then attached to the milled bar. Simulated mastication and repeated insertion/removal were performed over 400,000 cyclic loadings and 1,080insertions/removals, respectively. Wear patterns on deformed attachment were investigated by field emission scanning electron microscopy. @*RESULTS@#For the ADD-TOC attachments, chewing simulation and repeated insertion/removal resulted in a mean initial retentive force of 24.43 ± 4.89 N, which were significantly lower than that of the Locator attachment, 34.33 ± 8.25 N (P < .05). Amounts of retention loss relative to baseline for the Locator and ADD-TOC attachments were 21.74 ± 7.07 and 8.98 ± 5.76 N (P < .05). @*CONCLUSION@#CAD-CAM milled bar with the ADD-TOC attachment had a lower initial retentive force than the Locator attachment. However, the ADD-TOC attachment might be suitable for long-term use as it showed less deformation and had a higher retentive force after simulated mastication and insertion/removal repetitions.
RESUMEN
Purpose@#The purpose of this study was to evaluate the retentive characteristics of the additional attachments used with implant bar attachment under repeated insertion/removal cycles. @*Materials and methods@#The newly developed attachment and the commercially available attachment were investigated: ADD-Lock (AL), Locator blue (LB). Two fixtures were placed parallel to each other on the custom lower mounting, and patrix of each attachment was fixed to the fixture. Also, the matrix of each attachment was placed on the opposing upper mounting. A universal testing machine was used to measure the retentive force during initial, 100, 250, 500, 1000, 2000, and 2500 repeated insertion/removal cycles. Wear and deformation of the attachment s were observed by scanning electron microscopy (SEM).Mann-Whitney U test (α=.05) and wilcoxon signed-rank test (α=.05) were performed to compare retentive force between each group and before and after 2500 repeated insertion/removal cycles. @*Results@#In terms of initial retentive force and retentive force after 2500 repeated insertion/removal cycles, the AL group (15.24 ± 1.46 N and 9.74 ± 1.16 N) showed significantly smaller values than the LB group (43.53 ± 12.39 N and 22.99 ± 4.77 N) (P <.05). Also, in the loss of retentive force, the AL group (5.50 ± 1.08 N, 36.08%) showed a smaller value than the LB group (20.54 ± 11.89 N, 47.19%) (P <.05). Based on SEM analysis, The AL group showed noticeable wear and deformation in the patrix and the LB group in the matrix. @*Conclusion@#Locator showed a higher initial retentive force than newly developed attachment, while the loss of retentive force was also higher. Both additional attachments are considered to have sufficient retentive force after repeated insertion/removal cycles.
RESUMEN
Purpose@#The purpose of this study was to evaluate the retentive characteristics of the additional attachments used with implant bar attachment under repeated insertion/removal cycles. @*Materials and methods@#The newly developed attachment and the commercially available attachment were investigated: ADD-Lock (AL), Locator blue (LB). Two fixtures were placed parallel to each other on the custom lower mounting, and patrix of each attachment was fixed to the fixture. Also, the matrix of each attachment was placed on the opposing upper mounting. A universal testing machine was used to measure the retentive force during initial, 100, 250, 500, 1000, 2000, and 2500 repeated insertion/removal cycles. Wear and deformation of the attachment s were observed by scanning electron microscopy (SEM).Mann-Whitney U test (α=.05) and wilcoxon signed-rank test (α=.05) were performed to compare retentive force between each group and before and after 2500 repeated insertion/removal cycles. @*Results@#In terms of initial retentive force and retentive force after 2500 repeated insertion/removal cycles, the AL group (15.24 ± 1.46 N and 9.74 ± 1.16 N) showed significantly smaller values than the LB group (43.53 ± 12.39 N and 22.99 ± 4.77 N) (P <.05). Also, in the loss of retentive force, the AL group (5.50 ± 1.08 N, 36.08%) showed a smaller value than the LB group (20.54 ± 11.89 N, 47.19%) (P <.05). Based on SEM analysis, The AL group showed noticeable wear and deformation in the patrix and the LB group in the matrix. @*Conclusion@#Locator showed a higher initial retentive force than newly developed attachment, while the loss of retentive force was also higher. Both additional attachments are considered to have sufficient retentive force after repeated insertion/removal cycles.