A spartate Aminotransferase Activity in Crevicular Fluid From Dental Impiants

Aspartate aminotransferase (AST) is an enzyme normally confined to the cytoplasm of cells, but released to the exracellular environment upon cell death. Its levels are associated with the severity of experimental gingivitis and the loss of periodontal attachement. The aim of the present study was to investigate the presence and activity levels of AST in peri-implant crevic-ular fluid (PCF) healthy and diseased endosseous implants in order to assess if AST in PCF can be further studied as a possible objective diognostic aid in oral implantology.

Eighty-one fitures from 81 systemically healthy subject were divide into 3 groups, 27 healthy implants (HI), 27 implants with mucositis (MI) and 27 implants affected by periimplantities (PI)according to well-defined clinical and radiographic criteria. PCF was collected by the insertion of a # 40 standardized - point to the base of the crevice or pocket for 30 seconds. AST activity was determined spectrophotometrically at 25' C. The results were expressed as AST Units/ml in PCF.

An AST activity was detected in each sample from HI, MI and PI. The mean AST activity in HI was 0.26 f 0.16 U/ml; in MI, 0.38 ± 0.27u/ml; in PI, 0.62 k 0.29 U/ml. ANOVA showed that the deference among HI, MI, and PI was statistically significant at P <0.01level. Post-hoc tests demonstrated that a significant difference in AST activity existed between HI/PI (t = 5.14; P <0.01) and MI/PI (t = 3.09; P <0.01). No statistically significant difference was fond between HI/MI (t = 1.07; P>0.1) AST activity was significantly (P <1) associated with probing depth (r = 0.55), the amount of bone loss (r = 0.60) and bleeding on probing (r = 0.67). When the threshold for a positive AST test was set ≥0.4 U/ml, a sensitivity = 0.81 and a specificity = 0.74 were found in the detection of peri-implantitis; the positive predictive value was 61% and the negative predictive value was 88%.

within the limits of this study, our results may suggest the PCF analysis could be further investigated in longitudi-nal studies as a suitable diagnostic strategy in the evaluation of dental implants. J Periodontol2000;71:1151-1157.