Contact Allergy To Dental Materials In Patients With Early Onset Periodontitis B. Sigusch , A. Leister*, P. Hoffmann, A. Pfitzner, E. Glockmann (Dept. Of Conserv. Dentistry, Univ. Of Jena, Germany) Cutaneous immune responses involving T helper type 1 (Th1) and type 2 (Th2) cells characterized by secretion of interferon-g (IFNg) and interleukin-4 (IL-4). Rowe and Bunker 1998 (Contact Dermatitis,38;36-39) reported about increased IL-4 expression in allergic contact dermatitis lesions. We found in a recent study (J. Periodontol. 1998;69:1098-1104) that the PBMC response from periodontitis patients is predominantly Th2/ThO in nature. The aim of this study was to look after an association between the clinical features of gingivitis and periodontitis and the prevalence of positive patch test results to compounds of dental materials. 49 patients with gingivits group 1, n=14, age 23-54 yr; early onset periodontitis group 2, EOP, n = 17, age 21-37 yr and adult periodontitis group 3 AP, n=18, age 36-67 yr and healthy controls, n=14, age 21-61 yr, were patch tested (PT) to reveal contact allergy to dental filling materials. The following periodontal parameters were assessed: plaque index, bleeding index and probing pocket depth (6 sites/tooth). We differed between amalgam and plastic fillings, prothetic crowns, gold and silver-palladium fillings.   The subjects were patch tested with European standard series of dental material including mercury compounds. The plaque, bleeding, and filling values showed no statistically significant differences between the patient groups, except plaque and bleeding in comparison to controls (H test, p<0.001). The results revealed a significant increased number of positive patch test reactions in the EOP group (13/17) compared to the AP group 3/18 and group without positive PT reactions (Chi- square test, Fisher exact test p<0.0001). 7 patients were PT positive to amalgam or at least one mercury compound. Furthermore, we observed in patients with pocket depths ≥6 mm increased positive patch test results (75.5). On the other hand only 37.5 % of negative patch test patients had pocket depth ≥6 mm (p<0.001).   These data indicate that EOP patients are more involved in positive patch test reactions suggesting that deep periodontal pockets are related to an allergic disposition.