Retention Force and Wear Characteristics of three Attachment Systems after Dislodging Cycles

Abstract

Several attachment systems for mandibular implant-supported overdentures are currently available and studies are required to understand their mechanical properties. The objective of this study was to evaluate the retention force and wear characteristics of three attachment systems in a simulation of the cyclic dislodging of implant-supported overdentures. Thirty samples were fabricated and divided into 3 groups: 1-O-ring; 2-Mini Ball; and 3-Equator. A mechanical fatigue test was applied to the specimens using a servo-hydraulic universal testing machine performing 5500 insertion/removal cycles (f=0.8 Hz), immersed in artificial saliva. Retention force values were obtained before and after 1500, 3000, and 5500 cycles using a speed of 1 mm/min and a load cell of 1 kN. One specimen from each group was randomly selected and analyzed by scanning electron microscopy. Two-way repeated measures ANOVA and the Bonferroni post hoc test were used for statistical analyses (α=0.05). The O-ring system remained stable during all periods tested and exhibited significantly lower retention force values than the Mini Ball and Equator systems. The Mini Ball system exhibited a significant increase in retention force after the mechanical test (baseline=21.04±3.29N; 5500 cycles=24.01±3.30N).The Equator system exhibited a significant decrease in retention force after each period tested, but the values were higher than the other systems. The type of attachment was found to influence retention force in different ways after mechanical tests. The Equator system exhibited the highest retention force values. The Mini Ball and Equator matrices produced deformation and wear on the surfaces without breakage of the polyamide rings.

Single implant overdenture reinforced with a metallic framework: A 2‐year clinical follow‐up

“…13 Even though the increased retentive force of this component was not assessed in this study, the material properties of Equator polyamide rings, which are more rigid than a nitryl ball attachment, are worth noting. Such components may have deformed and worn 48 after the various insertionremoval cycles in the mouth. Moreover, as we selected subjects with a posterior bone height between 10 and 15 mm, the denture rotation owing to the height differences between the anterior and posterior regions could also have increased the frequency of matrix replacement.…”

Retention of bar clip attachment for mandibular implant overdenture

“…The achieved maximum values of retention force were recorded at the beginning of the study (initial retention) and after 1, 2, and 3 years with an average of 1000 cycles per year based upon patients’ average of 3 insertions and removals per day [ 22 , 25 ]. Twenty-four epoxy models and dentures were used (12 for each group) for proper statistical sample sizing.…”

İmplant Destekli̇ Overdenture Protezlerde Kullanilan Hassas Tutucular

“…44 Marin ve arkadaĢlarının O-Ring, mini ball ve equator sistemleri kıyasladıkları invitro çalıĢmada en yüksek retansiyon değeri, equator sistemde gözlenmiĢtir. 45 ġekil 10. OT Equator tutucu sistemi patriks ve matriksleri…”