Microscopic characterization of root surface-associated microbial plaque in localized juvenile periodontitis.

The purpose of this investigation was to characterize by scanning electron microscopy, the microbial morphotypes associated with the roots of teeth from patients exhibiting localized juvenile periodontitis (LJP). Eighteen teeth were examined from 10 adolescent patients who satisfied the standard clinical diagnostic criteria for LJP. The microscopic evaluation was facilitated by dividing that portion of the root exposed to the periodontal pocket into coronal, middle, and apical one-thirds. Controls consisted of an equal number of teeth matched as to pocket depth and anatomical type obtained from patients exhibiting adult periodontitis (AP). All specimens were coded and examiners were unaware of their origins. Results of the SEM evaluation revealed little difference in microbial morphotypes comprising the root associated plaque in the coronal one-third of LJP specimens when compared to the AP controls. The dominant microbial morphotypes were cocci, short and long rods, filamentous microorganisms, and spirochetes. However, microbial plaque located in the middle and apical one-third root zones of LJP specimens was distinctly different than that of AP specimens. In the deeper pocket zones the dominant microbial morphotypes in LJP specimens were limited to cocci, short rods, coccobacilli, and various sized spirochetes. In contrast, AP specimens exhibited a collection of microbial morphotypes consisting of cocci, short rods, long rods, filamentous organisms and spirochetes. Calculus was found on the root surfaces of all specimens regardless of disease category although, as a group, the LJP specimens featured lesser amounts. Although areas of root resorption were common in both LJP and AP groups, they were more frequently observed in LJP specimens, likely associated with the generally less confluent deposits of calculus and plaque.