Retention of Different Attachment Systems for Digitally Designed Mandibular Implant Overdenture

Abstract

Purpose: Primary retention and gradual loss of retention of different attachment systems are important key factors in proper attachment selection; however, studies on attachment retention show a wide range of retention values concerning the same attachment system. This in vitro study uses a novel approach that utilizes a digitally designed and 3D-printed reinforced overdenture, which has a digitally determined geometric center, in order to standardize results for future research and clinical work. This study aims to evaluate initial retention along with the gradual loss of retention at different time intervals between three types of stud attachments, retaining a digitally designed, reinforced mandibular overdenture after 5475 cycles simulating 5 years of attachment usage. Materials and Methods: An epoxy model of an ACP Class I (American College of Prosthodontists) edentulous mandible was constructed. A fully computer-designed surgical guide was employed after virtual denture design to place two implants according to prosthetically driven implant placement protocol. A metal meshwork with tissue stops was designed digitally to reinforce the denture and to carry the geometric center. The meshwork was incorporated into the denture-intaglio surface, which was planned for attachment pickup. Forty-eight digitally designed and metal-reinforced 3D-printed dentures were divided into four groups (12 dentures for each group). Loss of retention was measured to compare two novel Locator attachments (12 pairs of Locator R-TX, 12 pairs of Locator F-TX medium and low retention, with 12 pairs of ball and socket). Each group was subjected to an insertion and removal fatigue test resembling 5 years of patient usage. Retention values were recorded using a universal testing machine. Results: Locator F-TX medium and low retention showed loss of retention by 91.93% and 92.91%, after fatigue testing equivalent to 2 and 3 years of use, respectively. Ball and socket and Locator R-TX showed loss of retention by 19.87% and 26.31%, respectively, after fatigue testing equivalent to 5 years of use. Conclusions: Locator R-TX attachment systems showed promising retention for implant overdentures compared to ball and socket attachments. The proposed digital technique of denture reinforcement is capable of standardizing results for research and clinical work.

In vitro measurement of the retention force of two stud attachment systems during cyclic load

“…In comparable studies, the number of cycles performed ranges from 3000 to 30,000. [14][15][16][17][18][19][20][21][22][23] The sample size of 10 specimens for each test series is consistent with other studies even though there is no clear consensus. 14,16,17,22,24 In this study, the manufacturer's specifications could only be confirmed for the initial retention force of green Novaloc retention inserts on a Novaloc abutment (Ng-N) and for the white Novaloc retention inserts on a Novaloc abutment (Nw-N) as well as the green Novaloc retention inserts on a Locator abutment (Ng-L) after 10,000 cycles.…”

“…Current research indicates that the followup Locator R-Tx system may have a more stable retention pattern. 21 The simulation of mastication only seems to cause less wear of the legacy Locator inserts, as much lower retention losses were observed. 24 For Novaloc retention inserts, there are only a few publications with varying results.…”

Digital duplication of maxillary complete denture: A dental technique

“…Takeda et al 6 reported using 3D printing technology for denture duplication. Application of Crea‐lign gum material was done to mimic the natural gingival pink color and appearance 19 . The 3D printed supporting arms are only placed on the polished denture surface, as placing the supporting arms on the intaglio surface will affect future denture adaptation and retention in the patient's mouth 2 …”

“…Application of Crea-lign gum material was done to mimic the natural gingival pink color and appearance. 19 The 3D printed supporting arms are only placed on the polished denture surface, as placing the supporting arms on the intaglio surface will affect future denture adaptation and retention in the patient's mouth. 2 This denture replication technique may be indicated when patients are very comfortable with their existing dentures and would like a backup replicate with some modifications, such as denture relining, to use as a spare denture.…”

Retention of bar clip attachment for mandibular implant overdenture

“…The sample size was calculated using G Power version 3.1.9.2. and according to previous studies [ 8 , 25 , 26 ].…”