MAINTENANCE OF NEW ATTACHMENT 1 AND 4 YEARS FOLLOWING GUIDED TISSUE REGENERATION (GTR)

The aim of the present study was to evaluate periodontal tissue altera tions during the maintenance phase following GTR therapy. 18 patients (average age 54 years, range 39-79 years) with 19 local periodontal de fects were monitored longitudinally using clinical periodontal paramet ers and radiographic assessments of bone level changes. 6 out of origi nally 24 patients were not available at the 4-year examination (2 pati ents were unwilling to participate and in 4 patients root amputations or tooth extractions had to be performed). Evaluations were perfomed a t baseline, 3 months, 1 year and 4 years following GTR therapy (using non-resorbable Gore-Tex(R) Periodontal Material). The changes observed at the deepest site of each tooth treated by GTR were compared to tho se encountered in the entire dentition. Supportive periodontal therapy was performed according to the patient's individual needs between 3 a nd 12 times between the 1 and 4 years examination. The plaque index an d the gingival index at the 4 years examination were assessed and had increased to almost double the value of baseline, although the BOP rem ained lower compared to baseline data. Between the 1 and 4 years exami nations, 1.27 mm of clinical attachment was lost as a mean. Regarding the site of each tooth treated with GTR with the initially deepest pro bing pocket depth, 1.42 mm of clinical attachment was lost during the maintenace phase. However, compared to baseline data, 1.37 mm of new a ttachment could be maintained. The clinical attachment level was maint ained within +/-1 mm in 12 out of 19 sites during the 4 years of maint enance. At 7 sites, a loss between 2 and 5 mm occurred during the main tenace phase. Compared to the baseline values, 4 sites had lost greate r than or equal to 2 mm of clinical attachment resulting in a net loss . Between the 1 and 4 years observation, no significant change in bone height was observed. Multiple regression analyses showed correlations between the maintenance of the new attachment (expressed as change in probing attachment level) and a combination of factors such as number of recall visits during maintenance phase, age of the patient and % o f loser sites in the corresponding dentitions. It was concluded that a low incidence of gingival inflammation was a prerequisite for the mai ntenance of attachment levels gained by the GTR technique.