Antibiotic Prophylaxis Practices for the Prevention of Infective Endocarditis Among Japanese Dentists: A Questionnaire Survey of Members of the Hyogo Dental Association

<b>Background/Objectives:</b> International guidelines-including the 2017 Japanese Circulation Society-recommend antibiotic prophylaxis before invasive dental procedures only for patients with clearly defined cardiac conditions at increased risk of infective endocarditis (IE), primarily Class I or IIa. However, IE prevention is not systematically incorporated into Japanese dental education, and dentists' understanding of these indications remains unclear. We assessed dentists' knowledge of guideline-based cardiac and procedural indications for prophylaxis, as well as their clinical practices regarding timing, duration, and antibiotic selection. <b>Methods:</b> A self-administered questionnaire was mailed to 3109 members of the Hyogo Dental Association. The survey evaluated recognition of Class I and IIa cardiac indications, dental procedures requiring prophylaxis, and self-reported prophylactic practices. Respondents were grouped by years of practice (≤20 vs. ≥21 years). <b>Results:</b> Overall, 367 dentists responded (11.8%). Correct identification of Class I indications was high for prosthetic valves (83.4%) and previous IE (93.7%) but low for complex congenital heart disease (55.5%) and post-shunt surgery (52.0%). Recognition of Class IIa indications was limited (36.4-51.1%). Awareness of procedural indications was high for tooth extraction (92.9%) and periodontal surgery (84.3%) but low for subgingival scaling (47.6%) and root canal treatment (36.7%). Only 60.5% of dentists correctly understood that prophylaxis is indicated for a Class I/IIa cardiac condition and an invasive dental procedure. Furthermore, 32.5% of dentists administered antibiotics within 1 h before treatment, and single-dose regimens were uncommon (14.7%). Multi-day regimens were frequently used. Amoxicillin was the most commonly selected antibiotic (40.8%). No major differences were observed between the groups. <b>Conclusions:</b> Although dentists demonstrated good awareness of major procedural indications, substantial gaps remain in recognizing Class I and IIa cardiac indications and in adhering to guideline-recommended timing and duration. Targeted education and improved collaboration between medical and dental professionals are needed to promote evidence-based IE prevention and reduce unnecessary antibiotic use.