Prevalence and Progression of Periodontitis in Ankylosing Spondylitis

1. Our hypotheses on the relationship between periodontitis and AS are as follows; * The prevalence of periodontitis is higher in AS patients group than that of non-AS control group * Anti-TNF-α therapy would favorably affect the disease course of periodontitis. 2. Based on our hypotheses, the specific objectives of the present proposal are as follows; * The primary objective is to compare the prevalence rate of periodontitis between AS patient group and non-AS group. * The secondary objectives will be: * To observe the carriage rate of P. gingivalis in AS and non-AS groups * To identify clinical parameters associated with the severity of periodontitis in AS group. * To compare the progression of periodontitis at weeks 12 and 24 between AS and non-AS groups or between AS patients with and without anti-TNF-α treatment