NDAEB Theory Exam cheat sheet

Four-handed dentistry divides tasks into operating-zone (assistant) and transfer-zone (operator) movements; instruments pass within the assistant's zone at approximately 12 o'clock to 2 o'clock for a right-handed operator.

Instrument transfer rule: pass so the working end stays in the operator's field of view, handle first, and maintain a stable fulcrum; the assistant retrieves the used instrument simultaneously with delivery of the next.

Standard precautions apply to all patients: gloves, mask, eye protection, and gown; hand hygiene occurs before gloving and immediately after glove removal.

Sterilization indicators: autoclave pouches carry external chemical indicators and internal biological spore tests (Geobacillus stearothermophilus) at least weekly.

High-volume evacuation reduces airborne contaminants; the saliva ejector is not a substitute because it does not remove aerosols or retract tissue.

Moisture control sequence: place cotton rolls or dry angles, then evacuate, then isolate; a dry field is required before any adhesive or sealant step.

Emergency kit essentials include oxygen, epinephrine autoinjector or 1:1000 ampule, diphenhydramine, aspirin, and a glucose source; nitroglycerin is patient-supplied.

Operator and assistant seated posture: feet flat, thighs parallel to floor, patient's head near the operator's elbow level to limit spinal flexion.

ALARA principle: use the fastest receptor speed available (digital or F-speed film), rectangular collimation, and the shortest exposure time that yields diagnostic density.

Bisecting-angle technique: receptor placed as close to the tooth as anatomy allows; central ray directed perpendicular to the bisector of the angle formed by the receptor and the long axis of the tooth.

Paralleling technique: receptor parallel to the tooth, central ray perpendicular to both receptor and tooth; requires a holder and increases object-receptor distance, reducing magnification.

Bitewing exposure: central ray aimed at the occlusal plane at the contact area of interest (premolar bitewing at the second premolar, molar bitewing at the second molar), vertical angulation +10 degrees.

Periapical vertical angulation for maxillary posterior: approximately +30 degrees; mandibular posterior: approximately -10 degrees; anterior maxillary: +40 to +45 degrees; anterior mandibular: -15 to -20 degrees.

PID length affects divergence: a 16-inch PID produces less divergence and lower skin dose than an 8-inch PID for the same collimated field.

Film processing: developer 68-70 degrees F for 5 minutes (manual), fixer at least twice the developing time; digital sensors require no chemical processing.

Infection control: barriers cover the tube head, PID, control panel, and receptor holders; sensors are disinfected per manufacturer instructions and never autoclaved.

Bass (sulcular) brushing: filaments angled 45 degrees toward the gingival margin, gentle vibratory strokes, then roll toward the occlusal surface; covers sulcus and interdental areas.

Modified Stillman and Charter methods are alternatives for gingival recession and orthodontic appliances respectively; Charter places filaments at 45 degrees toward the occlusal plane.

Flossing sequence: about 18 inches of floss, wrap middle fingers, use 1-2 inches of fresh floss per embrasure, curve into a C-shape against each proximal surface.

Interdental aids by embrasure size: floss for tight contacts, interdental brushes for open embrasures and furcations, wooden or plastic picks for Type II embrasures.

Powered toothbrush evidence: oscillating-rotating designs reduce plaque and gingivitis modestly compared with manual brushing; technique still determines outcomes.

Tongue cleaning and denture care are part of daily hygiene; dentures are removed at night and soaked, not cleaned with abrasive toothpaste.

Fluoride dentifrice concentration: 1000-1500 ppm for adults and children over 6; a smear for children under 3 and a pea-sized amount for ages 3-6.

Instruction is documented with the aid taught, areas demonstrated, and patient's return demonstration to verify skill acquisition.

Cariogenic potential depends on frequency of fermentable carbohydrate exposure more than total amount; each exposure creates an acid challenge lasting roughly 20-30 minutes.

Stephan curve: plaque pH falls below the critical value of about 5.5 after sucrose exposure, then returns to baseline in 20-60 minutes depending on saliva flow and buffering.

Cariostatic foods include cheese, milk, nuts, and fibrous vegetables; cheese raises plaque pH and stimulates salivary flow.

Sugar substitutes: xylitol is non-cariogenic and inhibits mutans streptococci at 6-10 g per day divided into 3 or more exposures; sorbitol is also non-cariogenic but can cause laxative effects.

Sucrose, glucose, and cooked starch are highly cariogenic; starch alone is less cariogenic than starch combined with sugar.

Hidden sugars appear in sports drinks, flavored yogurt, ketchup, and dried fruit; label reading for added sugars is a counseling tool.

Erosion risk: carbonated drinks, citrus, and sports drinks lower enamel hardness; consumption with meals and rinsing with water afterward reduces exposure.

Nutrition counseling for caries risk addresses meal frequency, bedtime snacks, beverage choices, and water fluoridation status.

Dam selection: medium gauge (about 0.010 inch) for routine operative, heavy for endodontics and air abrasion, thin for severely tapered or sensitive teeth.

Punch hole size and spacing: holes for anterior teeth are smaller and closer together than for posterior teeth; the hole should be slightly smaller than the tooth circumference to seal the cervix.

Isolation sequence: test contacts with floss before punching, punch the pattern, lubricate the dam, seat the clamp on the anchor tooth first, then stretch the dam over subsequent teeth.

Clamp types: winged clamps (Ivory 8A, 14A) for posterior molars and premolars; butterfly or ferrule clamps for partially erupted or cervical lesions; clamp is placed before the dam in most techniques.

Inversion of the dam margin into the gingival sulcus with a blunt instrument or floss improves seal and prevents leakage.

Removal: cut the interproximal septa with scissors, remove the clamp last, inspect the field, and check that no fragment remains in the sulcus.

Contraindications: severe nasal obstruction (dam forces mouth breathing), latex allergy (use non-latex dam), and teeth with active periapical infection requiring drainage.

Latex-free dam materials include silicone and polyisoprene; document allergy status before application.

Coronal polishing removes extrinsic stain and plaque from the clinical crown only; it is not a substitute for scaling and does not remove calculus.

Indications: extrinsic stain from tobacco, coffee, tea, or chlorhexidine; before sealant or bonding; before fluoride application when a clean surface is needed.

Contraindications: newly erupted teeth with immature enamel, enamel hypocalcification, exposed dentin or cementum, and within 1 month of topical fluoride application or sealant placement.

Prophy paste grit: coarse for heavy stain, medium for routine, fine or floury for exposed dentin and children; paste contains fluoride in many formulations.

Technique: rubber cup or bristle brush on a slow-speed handpiece (about 1000-1500 rpm), light intermittent pressure, overlapping strokes, one quadrant at a time.

Sequence: begin with the least stained quadrant and finish with the most stained; rinse and evacuate thoroughly after each quadrant.

Air polishing is not a substitute for rubber-cup polishing on exposed dentin or restorative margins and is contraindicated with sodium-restricted diets when using sodium bicarbonate powder.

Documentation includes paste used, areas polished, and any sensitivity reported.

Topical fluoride varnish: 5% sodium fluoride (22,600 ppm F) or 2.26% fluoride ion; applied to dried teeth, sets on contact with saliva, and remains 4-6 hours.

Acidulated phosphate fluoride (APF) 1.23% is contraindicated on porcelain, composite, and glass ionomer restorations because the acid etches them; neutral sodium fluoride is the alternative.

Fluoride foam and gel trays: 1-4 minutes of contact time per manufacturer; patient must not eat, drink, or rinse for 30 minutes after gel or foam, and varnish has no post-application restriction beyond soft diet.

Fluoride mechanism: forms fluorapatite and calcium fluoride deposits, inhibits demineralization, and enhances remineralization at pH below the critical value.

Silver diamine fluoride (38%) is applied to arrest active cavitated lesions; it stains demineralized tissue black and is avoided on esthetically visible surfaces.

Fluoride toxicity: probable toxic dose is 5 mg/kg; calculate by body weight and know the office protocol for ingestion.

Fluoride is not applied before sealants or bonding because it reduces bond strength; sequence is polish, rinse, then sealant, with fluoride after or at a separate visit.

Patient instructions after varnish: avoid brushing and flossing for 4-6 hours, avoid hot beverages and alcohol, and eat a soft diet.

Alginate mixing ratio is water-to-powder by weight per manufacturer (commonly 1:1 for regular set); too much water produces a weak, grainy set.

Alginate setting time: regular set about 2-3 minutes, fast set about 1-2 minutes; working time is roughly half the setting time, so load the tray promptly.

Water temperature controls set: cooler water lengthens working time, warmer water shortens it; do not exceed manufacturer temperature range.

Tray selection: tray must cover all teeth and extend into the vestibule without impinging on the frenum; perforated or rim-lock trays retain alginate.

Mandibular impression: load tray, seat posterior teeth first, then anterior; instruct the patient to lift the tongue to clear the floor of the mouth.

Maxillary impression: seat posterior first with the tray rotated anteriorly to avoid trapping air in the palate; border molding by cheek and lip movement improves the vestibule.

Pouring: pour within 10-15 minutes or store in a sealed humid bag; alginate is dimensionally unstable and undergoes syneresis and imbibition.

Disinfection: rinse the impression, then disinfect per manufacturer (commonly sodium hypochlorite or iodophor) before pouring; label the cast with patient name and date.

Matrix selection: Tofflemire retainer with a metal band for Class II amalgam and composite; sectional matrices (e.g., Palodent-style) for tight proximal contacts in composite.

Tofflemire band seating: the band's smaller circumference goes gingivally; the retainer is placed from the buccal with the diagonal slot toward the gingiva.

Wedge function: separates teeth to compensate for band thickness, holds the matrix against the gingival margin, and prevents overhang.

Wedge selection: wood wedges are slightly larger than the embrasure and are placed from the buccal or lingual depending on access; light-cured or plastic wedges for visible-light-cured materials.

Wedging sequence: place the wedge before condensation or placement, and verify the matrix is tight at the cervical margin with an explorer.

Removal: cut or loosen the band, remove the wedge, then the retainer; check contacts with floss and inspect margins for flash.

Sectional matrix systems use a ring that provides separation, replacing the wedge's separating function while the wedge still seals the gingival margin.

Documentation notes the matrix type, tooth, and any contact or margin adjustment needed.

Liners protect the pulp and reduce microleakage under restorations when the preparation is shallow and no pulpal exposure exists.

Calcium hydroxide liner: bactericidal and stimulates tertiary dentin; placed in small increments over the deepest area only, because it has low compressive strength.

Glass ionomer liner/base: releases fluoride, bonds to dentin, and has adequate strength for a base; used under amalgam and composite when the preparation is deep.

Zinc oxide-eugenol and reinforced ZOE are sedative bases but inhibit polymerization of composite; they are not used beneath resin composites.

Varnish (copal) seals dentinal tubules but provides no thermal insulation; it is used under amalgam in shallow preparations.

Placement sequence: isolate, dry the preparation without desiccating dentin, apply liner to the axial wall only, then place the restorative material.

Do not place liner over exposed pulp; exposure requires pulp capping or endodontic referral and is outside this procedure's scope.

Liner thickness is thin (about 0.5 mm or less) to avoid interfering with the restoration's strength and occlusal anatomy.

Enamel etching: 30-40% phosphoric acid for 15-30 seconds on enamel; rinse thoroughly and dry until the enamel appears frosty white.

Dentin etching: 15 seconds with 32-37% phosphoric acid in total-etch systems; over-etching dentin collapses the collagen network and reduces bond strength.

Moist dentin technique: after etching and rinsing, leave dentin visibly moist (not wet) for total-etch adhesives; enamel should remain dry.

Self-etch adhesives combine etching and priming and do not require separate phosphoric acid on dentin; they are less technique sensitive but bond less to uncut enamel.

Bonding agent application: scrub or agitate per manufacturer, thin with gentle air to evaporate solvent, then light cure; a shiny, even surface indicates adequate film thickness.

Light curing: follow manufacturer irradiance and time (commonly 10-20 seconds per increment); hold the tip close to the surface and keep it perpendicular.

Contamination control: saliva or blood on etched enamel requires re-etching; gloves and suction must be managed to avoid oil or moisture contamination.

Etch is contraindicated on dentin near the pulp in deep preparations without a protective liner, and phosphoric acid must not contact gingiva or mucosa.

Sealant indications: deep, narrow pits and fissures, newly erupted molars with incomplete coalescence, and caries-free or incipient lesions; primary molars benefit when the child is caries-active.

Sealant contraindications: well-coalesced shallow fissures, frank cavitation, and partially erupted teeth where isolation cannot be maintained.

Isolation is the critical variable; a dry field from the moment of etching through curing determines retention.

Etching time for permanent enamel is 15-30 seconds with 35-37% phosphoric acid; rinse 10-15 seconds and dry until chalky white.

Filled (opaque) sealants resist wear better than unfilled sealants; both release no fluoride unless the formulation includes it.

Sealant over incipient caries is acceptable when the lesion is non-cavitated; sealant placement does not require removal of sound tooth structure.

Curing: 20 seconds with a halogen or LED light, tip close to the surface; check retention with an explorer after curing.

Recall: sealants are checked at each recall visit; partially lost sealant with sound margins may be repaired by adding material after re-etching.

Vital whitening uses carbamide peroxide (typically 10-22% for trays) or hydrogen peroxide (typically 3-10% in-office); carbamide peroxide releases about one-third of its weight as hydrogen peroxide.

Tray fabrication: take an alginate impression, pour a stone model, and fabricate a custom tray with reservoirs; the tray must extend 1-2 mm beyond the gingival margin and not impinge on the gingiva.

Tray fit check: no blanching of gingiva, no rocking, and the patient can seat the tray fully with light pressure.

Application: a small drop per tooth or a thin ribbon in the tray; excess material that contacts gingiva causes soft-tissue irritation.

Wear schedule: typically 2-4 hours daily or overnight depending on concentration; over-the-counter and in-office products follow different regimens per manufacturer.

Side effects: transient sensitivity and gingival irritation are the most common; desensitizing agents (potassium nitrate, amorphous calcium phosphate) may be used during treatment.

Contraindications: pregnancy, tetracycline staining (poor response), severe caries, and patients with unrealistic expectations; existing restorations do not whiten.

Post-treatment instructions: avoid staining beverages and tobacco for 48 hours, and expect shade rebound within 1-2 weeks as dehydration resolves.