An in vitro Study of the Contamination Remaining on the Surface of Used Healing Abutment and Impression Copings After Cleaning and Sterilizing

In daily dental practice, cleaning and sterilization of reusable components like healing abutments (HAs) and implant impression copings (IICs) are critical for preventing cross-infection and ensuring successful clinical outcomes. Although often designated as single-use, these titanium components are frequently reused after sterilization for economic reasons. Contamination from blood, saliva, epithelial tissue, and bacterial biofilms can persist even after standard sterilization, posing a risk for infection and implant failure. Proper decontamination is challenging due to strong protein adhesion on titanium surfaces. Phloxine B, a protein-staining dye, can detect residual contamination, with stereomicroscopy offering three-dimensional visualization of stained surfaces. This study aims to assess the effectiveness of different sterilization protocols in removing organic residues from reused HAs and IICs, highlighting the importance of meticulous cleaning to maintain hygiene and implant success. In this, thirty used healing abutments (HAs) and thirty used implant impression copings (IICs) were collected and evaluated in their "as received" condition. Samples were stained with Phloxine B and divided into three cleaning protocols: (1) Distilled water + Cidex OPA; (2) Distilled water + 5.25% NaOCl with 15-min ultrasonic cleaning; (3) Distilled water + NaOCl + ultrasonic cleaning followed by autoclaving. After treatment, each sample was examined under a stereomicroscope at 2x magnification. HAs were imaged at five key sites (B, C, S, D, O), and IICs at three (E, S) to assess residual contamination. Microscopic analysis showed that Distilled water + Cidex OPA was ineffective in reducing contamination on healing abutments and impression copings. Significant reduction was observed with Distilled water + NaOCl, especially on external surfaces. The combination of NaOCl with autoclaving showed the most effective decontamination across all regions of both components. This study revealed that standard cleaning and sterilization methods fail to completely eliminate contaminants from healing abutments and impression copings, with 99% showing residual proteins. Key words: Healing abutment, Impression copings, Sterilization, Phloxine B.