Differential dark field microscopy of subgingival bacteria as an aid in selecting recall intervals: results after 18 months

Differential dark field microscopic examination of subgingival microbial forms has been used to assign customized recall intervals to a population of adults with minimal periodontal disease. Results after 18 months indicate that a substantial proportion of the test subjects remained in good periodontal health despite the absence of regular biannual prophylaxes. One half of these subjects, who had not received a prophylaxis for periods of 15-18 months, did not demonstrate any detectable worsening of their periodontal status. No correlation could be established in this population between proportions of certain microbial forms and susceptibility to gingivitis.