Revisiting “Plaque Free Zone”- Island of Peace in a Zone of Conflict: A stereomicroscopic study

Aim: This study was undertaken to find if Plaque Free Zone (PFZ) indeed was a ubiquitous entity observed both on healthy and diseased teeth and further to compare the width of PFZ in healthy and diseased teeth. Material & Methods: Out of total 31 teeth, 18 teeth extracted from patients with chronic periodontitis and 13 teeth extracted from healthy individuals were examined. The teeth were stained and measurements of width of PFZ were made. Photomicrographs were taken at 20X magnification using a stereomicroscope & measurements were made using Image J software. The data obtained was subjected to statistical analysis. Results: A significantly wider PFZ was found on the surfaces of teeth of healthy group as compared to diseased group. Conclusion: Wider PFZ zone in healthy teeth may have a protective role preventing direct contact of bacteria with underlying periodontal ligament. Invasion of this zone during mechanical instrumentation needs to be avoided. Clinical Significance: The existence of plaque free zone has clinical implications. Instrumentation beyond the base of the pocket during SRP may upset the delicate balance existing at tooth sulcus/pocket interface.