Background: Diabetes mellitus (DM) is associated with complications and orodental disease. Whether screening for DM during orodental health visits is a potential option is yet to be established in Nigeria. This study aims at assessing the prevalence of hyperglycemia in orodental disease as a clinical scenario to capitalize for opportunistic screening. Materials and Methods: This study was undertaken in Catholic Hospital Abbi for Ndokwa communities and dental clinic of Eku Baptist Government Hospital, all in Nigeria. However, 474 individuals (433 community-based and 41 dental clinic-based) including 10 orodental cases were screened for hyperglycemia and waist-hip circumference indices. Blood lipid profiles were also performed. Based on fasting blood glucose levels, participants were grouped into non-diabetic (n = 172), prediabetic (n = 168), and diabetic (n = 78). A World Health Organization questionnaire on oral health was used to collect information on orodental disease risk factors. Data were analyzed with IBM SPSS 22 statistical package. Results: In the community-based cohort, the prevalence of hyperglycemia was 56.8%, including 38.8% prediabetes and 18.0% undiagnosed DM (UDM). In the dental-based group, 63.4% were hyperglycemic including 53.7% prediabetes and 9.7% UDM. There was significant difference (P < 0.05) in the ages of the participants in relation to glycemic status, with 17-29 years having the highest prevalence of UDM. However, 42.5% of the community-based clients had indication(s) of orodental disease. Conclusion: This is probably the first study to highlight higher prevalence of hyperglycemia from screening at a dental setting compared to general clinic. Opportunistic screening of DM in dental settings may be an option to consider during clients' orodental health visits.