Bone probing measurement as a reliable evaluation of the bone level in periodontal defects

Background: Evaluation of periodontal regeneration is usually made by clinical measurements despite their limitations in determining the precise nature of the healing response. In the present study, the possibility of using bone probing measurements under local anesthesia to determine bone level changes without a re-entry procedure was investigated. Methods: Thirty-eight (38) first molars in 28 patients with chronic periodontitis who were scheduled to have periodontal surgery were included in this study. A custom-made acrylic resin stent was used for proper orientation of the probe for the bone probing depth measurement as well as probing depth measurements and surgical and radiographic bone level evaluations. The mesial, distal, and middle sites in the buccal aspect of each tooth were used. The sites were divided into 2 groups according to probing depth: those with a probing depth < 4 mm and those with a probing depth ≥ 4 mm. Results: The probing depth was not significant in the difference between actual bone level (SBL) and bone probing depth (BP) (P >0.05). The greatest correlation to SBL was found with BP (γ = 0.92), followed by radiographic bone level (RBL) (γ = 0.69). The morphology of the defects had no significant effect on the difference between SBL and other measurements, while tooth surface and probing depth had significant effects on the difference between RBL and SBL. Conclusions: The results of this study suggest that, regardless of probing depth, probing surface, and the presence of intrabony defects, there is a minimal difference between the BP and SBL. Determining the bone probing depth measurement is a kind of reliable method to estimate the regenerated bone level following periodontal treatment.