Differential effects of abutment contamination within an internal hexagonal connection on preload formation and load-dependent preload loss.

purposeThe purpose of this MATERIALS AND

methodsInternal hexagonal implant-abutment assemblies were divided into three groups according to the degree of surface contamination: no contamination (CT0), partial contamination (CT3), and extensive contamination (CT6). Reverse torque values were measured after initial tightening to assess preload formation (pre-RTV). Specimens were then subjected to cyclic loading, after which post-loading reverse torque values were recorded (post-RTV), and absolute torque loss (ΔRTV) was calculated. Surface alterations were qualitatively assessed using scanning electron microscopy (SEM). Statistical analyses were performed to compare torque-related outcomes among groups.

resultsPre-RTV were significantly lower in the contaminated groups than in the uncontaminated control (

conclusionSurface contamination within an internal hexagonal implant-abutment connection adversely affects joint stability through two distinct mechanical stages. While the presence of contamination primarily compromises initial preload formation, extensive contamination accelerates preload loss under cyclic loading. These findings suggest that even subtle contamination, often overlooked clinically, may have meaningful implications for implant-abutment stability.