Author ORCID Identifier

https://orcid.org/0009-0005-5609-1866

Semester

Spring

Date of Graduation

2026

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Restorative Dentistry

Committee Chair

Bryan Weaver

Committee Member

Michael Bagby

Committee Member

Shelby Alexander

Committee Member

Arif Salman

Abstract

Abstract

Comparative Evaluation of Bending Resistance and Retentive Torque Stability of Zest Locator® and Straumann Novaloc® Abutments: An In Vitro Study

Hammad Ul Haq B.D.S.

Objective: To compare the mechanical performance of Locator® (Zest Anchors) and Novaloc® (Straumann) implant overdenture attachment systems connected to Straumann Bone Level Conical (BLC) implants under standardized cyclic and static off-axis loading conditions.

Materials and Methods: Ten Straumann BLC implants were divided into two groups (n = 5): Group 1 received Locator® abutments and Group 2 received Novaloc® abutments. All abutments were tightened to 35 N·cm and retightened after 10 minutes. Baseline removal torque values (RTV) were recorded. Specimens were then subjected to cyclic loading for 100,000 cycles at 100 cycles/min (approximately 1.67 Hz) under 65–120 N at 30° off-axis, followed by post-cyclic RTV measurement. After retightening, specimens underwent static off-axis loading up to the machine limit of 960 N, followed by post-static RTV measurement. Primary outcomes included removal torque values, change in torque after cyclic loading, software-generated “Automatic Young’s” values during static loading, and maximum load sustained. Statistical analysis was performed using non-parametric tests (p < 0.05).

Results: Both systems demonstrated acceptable mechanical performance under cyclic and static loading. The Novaloc® group showed a more favorable trend in preservation of removal torque after cyclic loading compared with the Locator® group, suggesting better preload maintenance under repeated functional loading. Following static loading, both groups showed increased removal torque values, likely due to settling or improved interfacial adaptation of the internal conical connection. The Novaloc® group also demonstrated higher stiffness-related “Automatic Young’s” values (p = 0.06). No catastrophic fracture occurred in either group before reaching 960 N. Qualitative inspection showed greater visible deformation of Locator® retentive inserts after cyclic loading.

Conclusion: Within the limitations of this in vitro study, both attachment systems performed satisfactorily on Straumann BLC implants. However, the Novaloc® system showed a more favorable overall biomechanical trend, including better preservation of removal torque, higher stiffness-related values, and less visible insert deformation.

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