Joe Smith, Age 50, Returns for Periodontal Maintenance Therapy Every

Joe Smith, age 50, returns for periodontal maintenance therapy every 3 months for 1 year after nonsurgical periodontal treatment for chronic periodontitis. The inflammation has been resolved, and periodontal probing depths have decreased from 5 mm or 6 mm to 4 mm or less in most treated areas, with the exception of the distal surface of #2, where the probing depth has increased from 4 mm to 6 mm. Radiographs reveal no change on #2 distal. Which of the following explains this finding?

A) Continuing clinical attachment loss
B) Error in periodontal probing technique
C) Calculus deposits affecting accuracy of initial reading
D) Inaccessibility and poor visibility in pocket areas
E) Healing of periodontal tissues