Longitudinal evaluation of aspartate aminotransferase in the crevicular fluid of implants with bone loss and signs of progressive disease

Aspartate aminotransferase (AST) has been shown to be a promising host mark er for periodontal disease progression. The aim of the present study was to analyze AST in the crevicular fluid (CF) of implants exhibiting peri-impla ntitis and to evaluate the association between AST levels and progressive a ttachment loss. Twenty patients who had received a total of 42 endosseous c ylindric titanium implants were examined. Radiographic assessment of preexi sting bone loss and clinical measurements, including electronic attachment of probing, presence or absence of plaque, bleeding on probing, and AST ana lysis in CF, were performed on 2 occasions 6 months apart. During this stud y period 13 of 168 sites in 7 patients experienced further loss of attachme nt greater than or equal to 1.0 mm (median 1.7 mm; interquartile range 0.4 mm). Evaluation of a positive AST test (greater than or equal to 300 mu lU) in site-specific diagnosis revealed low positive (8%) and high negative pr edictive values (92%), with a sensitivity of 15% and a specificity of 83%. These results indicate that, in contrast to periodontal disease, the assess ment of AST in peri-implant crevicular fluid may be of limited value as a d iagnostic and prognostic marker for periimplant disease.