Use of confocal microscopy for quantification of plastic remnants on rough titanium after instrumentation and evaluation of efficacy of removal

Purpose: Many experts have proposed the treatment of titanium surfaces with plastic or nonmetal tips to prevent damage to implant surfaces by metal instruments during professional cleaning. It is also known that any material that is softer than titanium may leave remnants of itself on the treated surface. The aim of this study was to quantify the surface area covered by plastic remnants after instrumentation with various plastic instruments and to evaluate the efficacy of the removal of these remnants by confocal microscopy. Materials and Methods: Twenty-seven rough-surfaced titanium disks were used for quantification of plastic remnants. Nine disks each were cleaned with (1) a plastic tip on ultrasonic scaler A, (2) a carbon tip on ultrasonic scaler B, or (3) a plastic curette. Three disks from each group were cleaned with a three-way syringe for 10 seconds, and three other disks were cleaned with 0.2% chlorhexidine-soaked cotton pellets. Images were obtained at random areas on each disk with a confocal microscope, and a digital image analysis program was used to quantify the area with autofluorescence. Results: Approximately 10% to 20% of the surface was covered with plastic remnants of the instrument, irrespective of the instrument used. These remnants were not removed with a three-way syringe or chlorhexidine-soaked cotton pellets. Conclusion: Plastic remnants remained after instrumentation, regardless of the instrument used. Moreover, the study highlighted the difficulty of removing all remnants with water spray or a chlorhexidine-soaked cotton pellet. This study suggests that confocal microscopy is a reproducible method for quantification that may be applied for future comparisons of methods to remove plastic residue. Further research is warranted to evaluate the biologic effects of plastic remnants.