BACKGROUND The primary issue in managing edentulous patients is the severely resorbed mandibular ridge,particularly in older individuals with diminished adaptive capacities.This compromised situation leads to the fabr...BACKGROUND The primary issue in managing edentulous patients is the severely resorbed mandibular ridge,particularly in older individuals with diminished adaptive capacities.This compromised situation leads to the fabrication of inadequate dentures that lack retention and stability,potentially causing psychosocial issues.AIM To determine the difference in retentive capacity between three attachment systems in implant-retained overdentures.METHODS Three edentulous mandibular models were fabricated using heat-cured polymethacrylate resin,with two implant replicas placed in the intra-foraminal region of each model.30 acrylic resin mandibular overdentures were fabricated with provisions for three different overdenture attachment systems:A prefabricated ball/O-ring attachment,a locator attachment system,and an equator attachment system.Each model was subjected to 15000 pulls using a universal testing machine to remove the overdenture from the acrylic model and the force data were recorded.RESULTS The ball/O-ring attachment system demonstrated superior retentive capacity for 15 years,while the locator and equator attachment systems maintained excellent retentive capacity for 5 years.CONCLUSION The ball/O-ring attachment system outperformed better than the other two attachment systems regarding retentive capacity.The locator and equator attachment systems presented sufficient retentive abilities until 15000 cycles.After 7500 cycles,significant differences in retentive force between the systems evolved.展开更多
Previously, the choice of prosthetic implant-retained overdentures has depended on data from previous studies about the retention-fatigue strength of the attachment system selected. Little or no data have been availab...Previously, the choice of prosthetic implant-retained overdentures has depended on data from previous studies about the retention-fatigue strength of the attachment system selected. Little or no data have been available on the correlation between the attachment system selected and the overdenture support configuration. The purpose of the present study was to evaluate the retention force and fatigue resistance of three attachment systems and four support designs of overdenture prosthesis. Four lower edentulous acrylic models were prepared and eight combinations of attachments groups were investigated in the study. These included: O-Rings with mini-dental implants (MDIs), Dalbo elliptic with Dalbo Rotex and fabricated flexible acrylic attachments with both MDI and Dalbo Rotex. The study was divided into four test groups: groups A and B, controls, and groups C and D, experimental groups. Control group A contained three overdenture supports: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with Dalbo Rotex screwed in. Control group B contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with Dalbo Rotex screwed in at the same MDI position, but on the left side of the model. Experimental group C contained three overdenture support foundations: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with MDI screwed in. Experimental group D contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with MDIs screwed in at the same MDI position, but on the left side of the model. Each group was further divided into two subgroups according to attachment type used. Five samples were prepared for each group. Retention force (N) values were recorded initially (0 cycles) and after 360, 720, 1440 and 2880 insertion and removal cycles. During the tensile test a cross-head speed of 10 mm/min was applied. Values of absolute force (AF) and relative force (RF) were statistically analyzed by two-way ANOVA and multiple comparison Tukey’s tests between groups and cycles periods. The results of fatigue tests showed a 50% reduction in retention force in the subgroups with flexible attachments. A triangular design of overdenture support foundations with O-Ring attachments revealed the lowest value of AF and a relatively high reduction in RF. The four overdenture support designs with flexible acrylic attachments improved the retention force and reduced the fatigue retention. Furthermore, the results of the investigation demonstrate that flexible acrylic attachments for both teeth and implant-supported overdentures offer a wide range of retention forces.展开更多
文摘BACKGROUND The primary issue in managing edentulous patients is the severely resorbed mandibular ridge,particularly in older individuals with diminished adaptive capacities.This compromised situation leads to the fabrication of inadequate dentures that lack retention and stability,potentially causing psychosocial issues.AIM To determine the difference in retentive capacity between three attachment systems in implant-retained overdentures.METHODS Three edentulous mandibular models were fabricated using heat-cured polymethacrylate resin,with two implant replicas placed in the intra-foraminal region of each model.30 acrylic resin mandibular overdentures were fabricated with provisions for three different overdenture attachment systems:A prefabricated ball/O-ring attachment,a locator attachment system,and an equator attachment system.Each model was subjected to 15000 pulls using a universal testing machine to remove the overdenture from the acrylic model and the force data were recorded.RESULTS The ball/O-ring attachment system demonstrated superior retentive capacity for 15 years,while the locator and equator attachment systems maintained excellent retentive capacity for 5 years.CONCLUSION The ball/O-ring attachment system outperformed better than the other two attachment systems regarding retentive capacity.The locator and equator attachment systems presented sufficient retentive abilities until 15000 cycles.After 7500 cycles,significant differences in retentive force between the systems evolved.
文摘Previously, the choice of prosthetic implant-retained overdentures has depended on data from previous studies about the retention-fatigue strength of the attachment system selected. Little or no data have been available on the correlation between the attachment system selected and the overdenture support configuration. The purpose of the present study was to evaluate the retention force and fatigue resistance of three attachment systems and four support designs of overdenture prosthesis. Four lower edentulous acrylic models were prepared and eight combinations of attachments groups were investigated in the study. These included: O-Rings with mini-dental implants (MDIs), Dalbo elliptic with Dalbo Rotex and fabricated flexible acrylic attachments with both MDI and Dalbo Rotex. The study was divided into four test groups: groups A and B, controls, and groups C and D, experimental groups. Control group A contained three overdenture supports: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with Dalbo Rotex screwed in. Control group B contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with Dalbo Rotex screwed in at the same MDI position, but on the left side of the model. Experimental group C contained three overdenture support foundations: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with MDI screwed in. Experimental group D contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with MDIs screwed in at the same MDI position, but on the left side of the model. Each group was further divided into two subgroups according to attachment type used. Five samples were prepared for each group. Retention force (N) values were recorded initially (0 cycles) and after 360, 720, 1440 and 2880 insertion and removal cycles. During the tensile test a cross-head speed of 10 mm/min was applied. Values of absolute force (AF) and relative force (RF) were statistically analyzed by two-way ANOVA and multiple comparison Tukey’s tests between groups and cycles periods. The results of fatigue tests showed a 50% reduction in retention force in the subgroups with flexible attachments. A triangular design of overdenture support foundations with O-Ring attachments revealed the lowest value of AF and a relatively high reduction in RF. The four overdenture support designs with flexible acrylic attachments improved the retention force and reduced the fatigue retention. Furthermore, the results of the investigation demonstrate that flexible acrylic attachments for both teeth and implant-supported overdentures offer a wide range of retention forces.
