This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Which of the following is not always a true odontogenic infection 
Select and explain. 
A. Periapical abscess, B. Periodontal abscess, C. Maxillary sinusitis, D. None of the above
C: Maxillary sinusitis
Answer: C: Maxillary sinusitis 
Explanation: → Orofacial infections may be odontogenic or non-odontogenic in nature.
→ Majory of odontogenic infections are caused by the endogenous bacteria present in the oral cavity. Eg: Periapical and periodontal infections.
→ Most of non-odontogenic infections are associated with an underlying medical condition Eg: Non-odontogenic infections of the skin, tonsils, or maxillary sinuses.
→ Occasionally, infections could develop following an anesthetic injection or a surgical procedure.