After a maxillary molar comes out

Correct answer: C. Lining of the maxillary sinus

• A. A dentigerous cyst has a thin, non-inflamed lining of two to four cells attached at the cementoenamel junction of an UNERUPTED tooth. This tooth was erupted.
• B. An odontogenic keratocyst has a thin, uniform PARAKERATINISED stratified squamous lining of six to eight cells with a palisaded, hyperchromatic basal layer and a corrugated luminal surface, characteristically in a non-inflamed wall.
• C. CORRECT. Pseudostratified ciliated columnar epithelium is RESPIRATORY epithelium — the Schneiderian membrane. Finding it in tissue retrieved from a maxillary molar socket means the antral floor was breached and sinus lining was removed, confirming an OROANTRAL COMMUNICATION. The chronic inflammatory infiltrate reflects the associated sinusitis or local irritation. Confirm the communication clinically — a gentle nose-blowing test, careful inspection, never vigorous probing — and treat by size: under 2 mm usually closes spontaneously with sinus precautions; 2 to 5 mm needs a figure-of-eight suture with precautions; over 5 mm needs a buccal advancement or palatal rotation flap.
• D. A radicular cyst is lined by NON-KERATINISED STRATIFIED SQUAMOUS epithelium of variable thickness with arcading rete ridges, in a fibrous wall densely infiltrated by chronic inflammatory cells. It is the option the recall paired this with, and the EPITHELIAL TYPE is the entire discriminator — squamous versus respiratory.

Note: One genuine nuance: a radicular cyst lying directly against the antral floor can occasionally show RESPIRATORY METAPLASIA in part of its lining. But the straightforward reading of respiratory epithelium in tissue from a maxillary molar socket is sinus lining. Sinus precautions to give: no nose blowing, sneeze with the mouth open, no straws, no smoking, and no forceful spitting for two weeks.

Correct answer: C. About three to five days

• A. Months describes slowly resorbing synthetics such as polydioxanone (PDS), or non-resorbable materials that persist indefinitely.
• B. Roughly three to four weeks is the figure for POLYGLACTIN 910 (Vicryl), a braided synthetic absorbable suture that is hydrolysed rather than digested and is the usual choice when a flap needs prolonged support.
• C. CORRECT. PLAIN GUT loses useful tensile strength within roughly three to five days and is fully resorbed in about a week. It is broken down by enzymatic digestion, and the oral environment accelerates this considerably — salivary enzymes and bacterial action mean intra-oral resorption is FASTER than the manufacturers' systemic figures suggest. That short window suits a flap needing only brief support, but it is too short for a large advancement flap under tension.
• D. Twenty-four hours would provide no meaningful wound support and describes no material in use.

Note: The comparison set worth holding: PLAIN GUT 3–5 days; CHROMIC GUT, treated with chromium salts to slow digestion, 7–10 days; POLYGLACTIN 910 around 3–4 weeks. Non-resorbable sutures — silk, nylon, PTFE — are removed at 5 to 7 days intra-orally. SILK handles and ties best but is braided and WICKS bacteria along its length, which makes it the least favourable choice for a contaminated site despite being the most pleasant to use.