Diagnostic accuracy of large language models in ICOP-based orofacial pain diagnosis: A comparative study

OBJECTIVE: To compare the diagnostic performance of ChatGPT 5.5, Claude Opus 4.1, Gemini 3 Flash, and Grok 4 in International Classification of Orofacial Pain (ICOP)-based clinical scenarios. METHODS: Thirty ICOP diagnoses were randomly selected, and corresponding clinical scenarios were manually developed. Each scenario was submitted to all models using standardized prompts in independent sessions. Two blinded evaluators assessed primary diagnosis accuracy, subclassification accuracy, clinical interpretation, and management recommendations. RESULTS: Overall performance differed significantly among models (p < .001). Grok 4 achieved the highest total score and outperformed the other models. No significant differences were found among ChatGPT 5.5, Gemini 3 Flash, and Claude Opus 4.1. Subclassification accuracy was consistently lower than primary diagnosis accuracy, while management recommendations did not differ significantly. CONCLUSION: LLM performance varied across ICOP-based scenarios. Although Grok 4 showed the highest diagnostic concordance, current LLMs should support, not replace, clinician judgment.