Iran OMFS Board Exam flashcards

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Winter classification

Classification of mandibular third molar angulation based on the angle between the long axes of the second and third molars: mesioangular, distoangular, horizontal, vertical, buccoangular, and linguoangular.

Pell and Gregory classification

Classifies mandibular third molars by available space anterior to the anterior border of the ramus (Class I-III) and by depth relative to the occlusal plane of the second molar (Position A-C).

Alveolar osteitis

Dry socket occurring 2-4 days after extraction, with severe throbbing pain, an empty socket, exposed bone, and no purulence; treated by irrigation and a medicated dressing, not routinely antibiotics.

Odontogenic keratocyst histology

Parakeratinized stratified squamous lining with a corrugated surface, palisaded hyperchromatic basal cells, and satellite cysts; high recurrence and associated with PTCH1 mutations.

Ameloblastoma histology

Odontogenic epithelium with peripheral palisading and reverse polarity, stellate reticulum-like centers, and cystic degeneration; the unicystic mural type has higher recurrence.

Pleomorphic adenoma

Benign salivary gland tumor with epithelial and myoepithelial cells in a chondromyxoid stroma; the capsule may be incomplete, so enucleation alone risks recurrence.

Le Fort II fracture

Pyramidal midface fracture passing through the nasal bones, frontal process of the maxilla, infraorbital rim, and pterygoid plates, separating the maxilla from the cranial base.

Orbital blowout fracture

Fracture of the orbital floor with herniation of orbital contents into the maxillary sinus; trapdoor fracture with muscle entrapment in children requires urgent repair.

Avulsed permanent tooth

Replant immediately or store in milk or saline; use a flexible splint for up to two weeks; avulsed primary teeth are not replanted because of damage to the developing permanent tooth.

BSSO nerve risk

Bilateral sagittal split osteotomy risks the inferior alveolar nerve during the split and the lingual nerve during medial osteotomy and retraction; the proximal segment must be seated in the fossa.

Distraction osteogenesis protocol

Latency of 5-7 days, distraction at about 1 mm per day, and consolidation of 6-8 weeks or more; used for mandibular hypoplasia and craniofacial syndromes.

Le Fort I advancement limits

Maxillary advancement of about 5-10 mm is usually possible; larger movements need bone grafting and may affect velopharyngeal function; the descending palatine artery is at risk during downfracture.

Disc displacement without reduction

The disc does not reduce on opening, causing limited opening, deviation to the affected side, and no click; managed initially with conservative therapy and physiotherapy.

Trigeminal neuralgia

Paroxysmal electric shock-like pain in the V2 or V3 distribution triggered by touch, chewing, or cold; carbamazepine is first-line and MRI excludes secondary causes.

TMD first-line care

Patient education, self-care, soft diet, NSAIDs, physiotherapy, and an occlusal splint; irreversible occlusal adjustment is not first-line therapy for temporomandibular disorders.

Free fibula flap

Vascularized bone flap supplied by the peroneal artery and septocutaneous perforators; reliable for mandibular reconstruction; contraindicated if the peroneal artery dominates foot perfusion.

Guided bone regeneration

Barrier membrane plus particulate graft to exclude soft tissue and allow bone formation; membrane exposure is the main complication, so primary closure and soft tissue thickness are critical.

Medication-related osteonecrosis

Exposed jaw bone for more than eight weeks in a patient on antiresorptives or antiangiogenics; conservative management first, with surgery reserved for advanced stages.

Recurrent aphthous stomatitis

Minor ulcers are under 1 cm and heal in 1-2 weeks; major ulcers exceed 1 cm and scar; herpetiform ulcers are multiple small lesions; topical corticosteroids are first-line.

Pemphigus vulgaris

Intraepithelial IgG autoantibodies against desmoglein 1 and 3; flaccid bullae, positive Nikolsky sign, and intercellular IgG on direct immunofluorescence.

Sjögren syndrome

Dry eyes and mouth with anti-Ro/SSA and anti-La/SSB antibodies and focal lymphocytic sialadenitis on labial gland biopsy; associated with increased lymphoma risk.

Ludwig angina

Bilateral submandibular and sublingual space infection with floor-of-mouth elevation and tongue displacement; management is airway control, IV antibiotics, and surgical drainage.

Cavernous sinus thrombosis

A complication of midface infection spreading via the angular and ophthalmic veins; signs include proptosis, ophthalmoplegia, and fever; requires IV antibiotics and imaging.

Odontogenic infection flora

Polymicrobial with streptococci and anaerobes such as Prevotella, Porphyromonas, and Fusobacterium; amoxicillin-clavulanate or clindamycin are common choices.

Lidocaine maximum dose

Lidocaine 2% with 1:100,000 epinephrine has a maximum dose of about 4.4 mg/kg (up to 7 mg/kg with epinephrine in some guidelines); calculate cartridges before injection.

Malignant hyperthermia

Triggered by volatile anesthetics and succinylcholine; signs include hyperthermia, rigidity, and hypercarbia; treat with dantrolene and supportive care.

Flumazenil

A benzodiazepine antagonist used to reverse midazolam sedation; it can precipitate seizures in chronic benzodiazepine users and does not reverse respiratory depression from other agents.

Cleft lip repair timing

Usually performed at 3-6 months using the rule of 10s: weight over 10 lb, hemoglobin over 10 g/dL, and age over 10 weeks.

Cleft palate repair timing

Typically performed at 9-18 months to close the defect, restore the levator sling, and preserve the greater palatine blood supply.

Alveolar bone grafting

Performed at 6-12 years before canine eruption in cleft patients; the iliac crest is a common donor; it provides bone support and allows tooth eruption.

Marginal mandibular nerve

A branch of the facial nerve at risk in submandibular surgery; injury causes weakness of the depressor anguli oris and depressor labii inferioris, with asymmetric lower lip movement.

Sensitivity and specificity

Sensitivity is true positives divided by all diseased; specificity is true negatives divided by all nondiseased; both are intrinsic test properties independent of disease prevalence.

Number needed to treat

The reciprocal of the absolute risk reduction; it estimates how many patients must be treated for one additional beneficial outcome.

Informed consent elements

Disclosure of diagnosis, proposed treatment, alternatives, risks, benefits, and consequences of no treatment; documented and obtained by the treating clinician before the procedure.

Negligence elements

Duty of care, breach of that duty, causation, and damages; expert testimony is often required to establish the standard of care.