Iran Dental Basic Sciences Exam flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Foramen ovale transmits

The mandibular division (V3) of the trigeminal nerve, along with the lesser petrosal nerve and accessory meningeal artery, passes through this opening in the sphenoid bone.

Chorda tympani function

Branch of the facial nerve that carries taste from the anterior two-thirds of the tongue and parasympathetic secretomotor fibers to the submandibular and sublingual salivary glands.

Ameloblast origin

Ameloblasts differentiate from the inner enamel epithelium of the enamel organ, which is of ectodermal origin, and secrete enamel matrix before undergoing apoptosis after tooth eruption.

Resting membrane potential

Approximately −70 mV in neurons and muscle, determined mainly by potassium permeability through leak channels and maintained by the sodium-potassium ATPase pump.

Saliva hypotonic mechanism

Acinar cells produce isotonic primary saliva; ductal cells reabsorb sodium and chloride and secrete potassium and bicarbonate, yielding final hypotonic saliva rich in mucins and amylase.

Gate control theory

Pain transmission in the dorsal horn is inhibited by concurrent large-fiber (A-beta) mechanoreceptor input, explaining why rubbing or vibration reduces perceived pain.

PFK-1 regulation

Phosphofructokinase-1 catalyzes the committed step of glycolysis; it is inhibited by ATP and citrate and activated by AMP, fructose-2,6-bisphosphate, and insulin signaling.

Vitamin C in collagen

Ascorbate is a cofactor for prolyl and lysyl hydroxylase, enabling collagen triple-helix stability and cross-linking; deficiency causes scurvy with bleeding gums and poor healing.

Fluoride anticaries mechanism

Fluoride inhibits bacterial enolase, reducing lactic acid production, and promotes fluorapatite formation in enamel, which is more acid-resistant than hydroxyapatite.

Streptococcus mutans virulence

This cariogenic oral streptococcus uses glucosyltransferases to synthesize adhesive glucans from sucrose and produces lactic acid, thriving at low pH on tooth surfaces.

Red complex bacteria

Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola form a microbial consortium strongly associated with chronic periodontitis and deep periodontal pockets.

Candida albicans features

Opportunistic yeast forming pseudohyphae and germ tubes; causes denture stomatitis, angular cheilitis, and oral thrush in xerostomia or immunosuppression; treated with nystatin or fluconazole.

Salivary immunoglobulin

Secretory IgA is the predominant antibody in saliva and mucosal secretions, neutralizing pathogens and preventing bacterial adherence to oral surfaces.

Autoclave sterilization parameters

Standard steam sterilization uses 121 degrees Celsius at 15 psi for 15 to 20 minutes; effectiveness is verified with Geobacillus stearothermophilus spore tests.

Granuloma composition

A chronic inflammatory lesion composed of epithelioid macrophages, Langhans giant cells, and surrounding lymphocytes, seen in tuberculosis, sarcoidosis, and foreign-body reactions.

Radicular cyst origin

The most common inflammatory odontogenic cyst, arising from epithelial rests of Malassez in a periapical granuloma; lined by non-keratinized stratified squamous epithelium.

Ameloblastoma features

Benign but locally aggressive odontogenic epithelial tumor, most common in the posterior mandible of adults; radiographically multilocular soap-bubble radiolucency; requires wide resection.

Odontoma types

Most common odontogenic tumor; compound type contains multiple small tooth-like structures, while complex type is an irregular mass of dental hard tissues.

Oral SCC risk factors

Squamous cell carcinoma of the oral cavity is linked to tobacco, alcohol, betel quid, and HPV (especially oropharyngeal); lateral tongue and floor of mouth are common sites.

Local anesthetic mechanism

These agents block voltage-gated sodium channels from the cytoplasmic side, preventing depolarization; the uncharged form crosses the membrane, and the charged form binds the channel.

Epinephrine in anesthesia

Vasoconstrictor added to local anesthetics that reduces systemic absorption, prolongs duration, and controls bleeding; caution in uncontrolled hypertension and with nonselective beta-blockers.

Lidocaine maximum dose

Approximately 4.4 mg/kg without vasoconstrictor and 7 mg/kg with epinephrine in adults; exceeding this risks CNS excitation followed by seizures and cardiovascular depression.

Amoxicillin in dentistry

First-line antibiotic for odontogenic infections, typically 500 mg three times daily; in penicillin allergy, clindamycin or azithromycin is substituted, with metronidazole for anaerobes.

Amalgam gamma-2 phase

The tin-mercury phase is weak and corrosion-prone; high-copper amalgams reduce its formation, improving strength and marginal stability compared with conventional low-copper amalgams.

Composite polymerization shrinkage

Resin matrix contraction during curing creates stress at margins; incremental layering, lower C-factor configurations, and proper light curing reduce gap formation and postoperative sensitivity.

Glass ionomer properties

Dental cement releasing fluoride, chemically bonding to enamel and dentin, with low strength and high solubility; resin-modified versions add light-cured resin for improved properties.

Addition silicone accuracy

Polyvinyl siloxane impression material is the most dimensionally stable elastomer with low shrinkage and high tear strength, making it preferred for precise crown and bridge impressions.

X-ray attenuation law

Intensity decreases as I = I0 times e to the minus mu-x; higher density and atomic number increase attenuation, so enamel, bone, and metal appear radiopaque.

ALARA principle

Dose is kept as low as reasonably achievable using rectangular collimation, lead apron and thyroid shield, fast film or digital sensors, and selecting exposures only when justified.

Cone beam CT advantage

Provides three-dimensional imaging of maxillofacial structures at lower radiation dose than medical CT, useful for implant planning, impacted teeth, and endodontic assessment.

Informed consent elements

Valid consent requires patient capacity, disclosure of diagnosis, risks, benefits, and alternatives, patient understanding, and voluntary agreement, all documented in the record.

Tell-show-do technique

Behavioral management for anxious or pediatric patients: explain the procedure in simple terms, demonstrate instruments, then perform it, reducing fear through familiarity.