Six mоnths аgо, yоur pаtient hаd generalized gingivitis with moderate plaque biofilms present. With the help of professional care and new daily self-care techniques, at today's appointment the periodontium is healthy with very little plaque biofilm present. The one exception is the facial of tooth #29 that exhibits gingivitis. All of the following factors might contribute to the gingivitis in this one site, except: