BackgroundThis cross-sectional study aimed to determine the prevalence of different stages of periodontal diseases based on the recent classification in a sample of young adult obese Egyptian dental outpatients.MethodsThis study included 314 patients seeking dental treatment at the Diagnostic Center of the Dental hospital, Faculty of Dentistry, Cairo University. Validated oral health questionnaire for adults regarding their age, gender, level of education and oral health routines as well as oral health impact profile questionnaire for chronic periodontitis (OHIP-CP) were filled by all patients. Obesity parameters were also assessed through person’s weight in kilograms, height in centimeters and waist circumference to determine the obesity stage. Diagnosis was made based on measurements of clinical periodontal parameters including a full mouth plaque index (PI), bleeding on probing (BoP), pocket depth (PD), clinical attachment level (CAL) and gingival recession depth (RD). Radiographic examination was performed using periapical radiographs. Ordinal logistic regression analysis was used to determine significant predictors of periodontal diseases and discriminant analysis was performed to predict periodontal disease classification. ResultsThe age range in the study sample was 19–39 years old. The prevalence of different stages of periodontal diseases was 100%. Gingivitis was the most prevalent periodontal disease (63.7%) followed by Periodontitis Stage III (22.6%) then Stage II (11.1%). Stage I showed the least prevalence (2.5%). An increase in BMI was statistically associated with an increase in PD, CAL, RD, PI and vice versa (P-value < 0.05). The total OHIP-CP was 15.99 ± 3.06 for all participants.ConclusionsThere was a statistically significant association between periodontal diseases and obesity in young adults, as well as a statistically significant direct correlation between BMI and periodontal parameters. Self-assessment of oral health and obesity were significant predictors of periodontal disease.Clinical trial Registration IDNCT04618068.