Background <p>Alveolar bone loss (ABL), tooth mobility, tooth displacement, and tooth loss due to periodontitis can lead to temporomandibular joint (TMJ) problems and reduced masticatory function. While previous studies have examined the associations between periodontal disease, bite force (BF), and temporomandibular disorders (TMDs) separately, the combined impact of periodontal breakdown on both masticatory function and TMJ involvement has not been clearly established. Therefore, this study aimed to determine the relationship between ABL and BF and to evaluate the incidence and characteristics of TMDs in patients with periodontitis.</p> Methods <p>This cross-sectional study enrolled 50 patients with stage III generalized periodontitis and 50 periodontally healthy participants. Sociodemographic data and clinical periodontal parameters were collected. BF was measured and compared between periodontitis and periodontally healthy groups. The TMJ was assessed using an interview-based questionnaire and clinical examination.</p> Results <p>TMD pre-diagnostic classifications were not significantly different between the groups (<i>p</i> = 0.772, <i>p</i> &gt; 0.05). Complaints of pain in the jaw upon waking (<i>p</i> = 0.044), clicking/locking of the jaw (<i>p</i> = 0.020), and daytime bruxism (<i>p</i> = 0.042) were significantly fewer in the periodontitis group than in the healthy group (<i>p</i> &lt; 0.05). Meanwhile, TMJ-related symptoms were not significantly different between the periodontitis and healthy groups. However, BF was significantly lower in the periodontitis group than in the healthy group (<i>p</i> &lt; 0.001).</p> Conclusions <p>BF is decreased in patients with periodontitis. Periodontal treatment should be completed, and missing teeth, if any, should be rehabilitated to enable efficient masticatory function in these patients.</p>