Effect of Various Retentive Element Materials on Retention of Mandibular Implant-Retained Overdentures

Abstract

This study aimed to examine the retentive characteristics of each retentive element material and the effects from thermocycling using the two implant-retained mandibular overdenture model. Two stud abutments and three retentive element materials; nylon, polyetheretherketone (PEEK) and polyvinylsiloxane (PVS) were used in this study. Four tested groups, with a total of 40 overdentures, were fabricated, including a Locator® abutment with nylon retention insert (NY), Novaloc® abutment with PEEK retention insert (PK), Locator® abutment with PVS retention insert (RL), and Novaloc® abutment with PVS retention insert (RN). The retentive force (N) was measured before thermocycling, and at 2500, 5000, and 10,000 cycles after thermocycling. Significant changes in the percentage of retention loss were found in the NY and PK groups (p < 0.05) at 6 and 12 months for the RL group (p < 0.05) after artificial aging. The RN group exhibited a constant retentive force (p > 0.05). The tendency of the percentage of retention loss significantly increased for PEEK, nylon, and PVS silicone over time. The results of the present study implied that retentive element materials tend to lose their retentive capability as a result of thermal undulation and water dispersion. Nylon and PEEK, comprising strong polar groups in polymer chains, showed a higher rate of retention loss than polyvinylsiloxane.

Effect of Implant Positions and Angulations on Retentive Strength of 2-Implant Mandibular Overdentures: An In Vitro Study with the New 3D-Printed Simulation Method

“…Biomaterials used to fabricate the retentive elements also play vital role in influencing the retention of the overdenture. Chindarungruangrat et al [ 13 ] studied the retentive force of retentive element materials using three retentive element materials: nylon, polyetheretherketone (PEEK), and polyvinyl siloxane (PVS). The retentive force (N) was measured before thermocycling and at 2500, 5000, and 10,000 cycles after thermocycling and it was concluded that the retentive element materials tend to lose their retentive capability because of thermal undulation and water dispersion.…”

“…Greater retentive strength may also affect the longevity of the flexible matrix [6][7][8][9]. Maximum studies evaluated the retentive strengths of 2IMO after simulated function and very few evaluated the stresses at baseline without age simulation [9,[11][12][13][14][15]. e attachments are serviceable from the first day of their usage in mouth; hence, the present study evaluated their retentive strength without any age simulation.…”

“…Biomaterials used to fabricate the retentive elements also play vital role in influencing the retention of the overdenture. Chindarungruangrat et al [13] studied the retentive force of retentive element materials using three retentive element materials: nylon, polyetheretherketone (PEEK), and polyvinyl siloxane (PVS).…”

“…Many investors evaluated the effect of cyclic loading on stud attachment wear [9,[11][12][13][14][15] and initial retention was significantly higher than retention after wear or simulated clinical function under different number of insertion-removal cycles for different type of inserts. However, the literature lacks the information on the retentive strength of the attachments without insertion-removal cycles which simulates the overdenture usage from the first day.…”

“…e gingival and bleeding index of the patients were not influenced by any of the unsplinted attachments (stud, magnet, and telescopic) studied [16]. Most of these studies [11][12][13][14][15][16][17] used canine position as a standard position in 2IMO patients.…”