Impact of increased occlusal contact, interleukin-1 genotype, and periodontitis severity on gingival crevicular fluid IL-1beta levels.

BACKGROUND: The study of occlusal therapy in humans with periodontitis is problematic due to potential irreversible bone loss in control subjects. The hypothesis of this pilot investigation was that increased interocclusal contact initiated by short-term occlusal splint disuse would increase tooth mobility and the bone-resorptive cytokine interleukin (IL)-1beta in gingival crevicular fluid (GCF), comparable to IL-1-positive genotype and increased periodontitis severity.

METHODS: Nineteen non-smoking chronic periodontitis patients using nocturnal occlusal splints and undergoing periodontal maintenance in a private practice were evaluated at five time points: 24 hours after continuous splint use; 1, 2, and 3 days after no occlusal splint use; and 14 days after resumption of customary nighttime splint use. Subjects were evaluated to confirm that the plaque index and gingival index were < or = 1.0, and to categorize past periodontitis (moderate or severe) and IL-1 genotype (1A +4845 plus IL-1B +3954). Test sites on two anterior teeth vulnerable to occlusal trauma were sampled for mobility, GCF IL-1beta, and IL-1 receptor antagonist (ra).

RESULTS: Tooth mobility remained low during the 3-day period when patients were not wearing their occlusal appliance. GCF IL-1beta decreased after not wearing the appliances (P = 0.016), especially at 48 hours. At this time, genotype-positive subjects had higher levels of GCF IL-1beta/IL-1ra than genotype-negative subjects (P = 0.045), and patients who had experienced severe periodontitis had higher IL-1beta levels than moderate periodontitis subjects (P = 0.004).

CONCLUSIONS: These findings suggest that short-term discontinuation of occlusal splint therapy in non-smoking periodontitis patients undergoing periodontal maintenance does not result in potential signs of early occlusal trauma (increasing mobility or GCF IL-1beta). Longer-term studies may be needed to determine appropriate therapy applications for periodontitis-susceptible patients with definable occlusal discrepancies and/or parafunction.