The effect of post-surgical flap placement on probing depth and attachment level: a 2-year longitudinal study

Postsurgical flap placement might affect the outcome of the operative procedure. Modified Widman flap surgery with primary closure and flap approximation (usually away from the bone crest) and apically positioned flap surgery with near crestal bone positioning are both widely used in surgical periodontal treatment. Several comparative investigations have studied these modalities, however, none have been able to show conclusively that either is superior to the other. The purpose of this longitudinal study was to explore the optimal postsurgical flap placement in respect to final probing depth and changes in clinical attachment level. Following routine hygienic phase of treatment, 12 subjects (186 teeth) with adult periodontitis received surgical periodontal treatment. Prior to the flap surgery, probing depth and clinical attachment level were recorded. Sounding depth measurements were taken to record postoperative flap placement. Patients were placed on a 3-month maintenance program. Probing depth and clinical attachment level were again measured at 2 years postoperatively and compared to baseline measurements. An overall positive correlation (R = 0.43; P = 0.0248) was found between immediate postoperative sounding measurements and probing depth after 2 years. Conversely, attachment level changes over the 2-year period showed only weak inverse correlation (R = 0.27; P = 0.0121) with sounding depth measurement immediately postsurgically. Sites where postoperative sounding depth were < or = 3 mm had a mean probing depth (2.52 mm) which was significantly (P < 0.001) smaller compared to sites with sound depth > or = 4 mm (3.58 mm). Changes in clinical attachment level varied between sites and sounding depth groups; however, none of these differences were statistically significant. Based on our findings it is suggested that following periodontal flap surgery, in those cases where minimal probing depth is desired, the flap be secured to the underlying structures at or slightly coronally to the bone crest (< or = 3 mm).(ABSTRACT TRUNCATED AT 250 WORDS)