Trauma, pigmented lesions, anaesthetics and confidentiality

Correct answer: D. Wash it with chlorhexidine

• A. A brief rinse with saline to remove gross debris is appropriate. Never scrub the root.
• B. Milk is an excellent transport medium — its osmolality and pH preserve ligament cell viability. Hank's balanced salt solution is better still.
• C. The tooth must be handled by the crown only. Touching the root damages the ligament cells directly.
• D. Correct — this is the thing to avoid. Chlorhexidine is cytotoxic to the periodontal ligament cells whose survival determines whether the tooth reattaches. Antiseptics have no place on the root surface.

Note: Replanting the tooth into the socket at the scene is the best outcome of all. Extra-oral dry time beyond 60 minutes makes ligament survival very unlikely.

Correct answer: C. Melanotic macule

• A. Physiologic pigmentation is symmetric, bilateral, most often on attached gingiva, and present since childhood — not a solitary premolar-region lesion.
• B. Amalgam tattoo is a strong contender, and fine particles are frequently invisible radiographically. A history of a nearby restoration or extraction supports it; here the absence of radiopacity shifts the odds.
• C. Correct. A solitary, flat, well-circumscribed brown lesion with no radiographic particles is most consistent with a melanotic macule — a benign focal increase in melanin.
• D. Melanoma is rare in the mouth but must be considered for any pigmented lesion. Irregular borders, colour variation, growth or asymmetry make biopsy mandatory.

Note: ⚑ No key was marked in the recall for this item. The safe clinical rule matters more than the answer: a solitary pigmented lesion that cannot be confidently explained by a local cause should be biopsied.

Correct answer: D. Methaemoglobinaemia

• A. Local anaesthetics are not characteristically nephrotoxic.
• B. Ototoxicity belongs to the aminoglycosides and to high-dose loop diuretics.
• C. Malignant hyperthermia is triggered by volatile anaesthetics and succinylcholine, not by local anaesthetics.
• D. Correct. Benzocaine, an ester, is the agent most associated with methaemoglobinaemia — the patient becomes cyanotic and the oxygen saturation fails to improve with oxygen. Methylene blue is the antidote.

Note: Prilocaine, an amide, causes methaemoglobinaemia by a different route — its metabolite o-toluidine. Esters are also the group associated with allergy, because of the PABA metabolite.

Correct answer: C. Staff members involved in that patient's treatment, payment or operations

• A. An accompanying friend or neighbour has no right of access at all.
• B. Another provider may receive information for treatment purposes, but not open access to the record for the asking.
• C. Correct. Under HIPAA, use and disclosure for treatment, payment and health care operations is permitted without separate authorisation — but only on a minimum-necessary basis, for staff genuinely involved in that patient's care.
• D. A spouse has no automatic right of access. Authorisation is required unless the patient is present and does not object, or lacks capacity.