NDAEB Theory Exam flashcards

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

Four-handed dentistry zones

The assistant works in the operating zone near the patient's oral cavity, while the operator works in the transfer zone. Instruments pass within the assistant's zone at about 12 to 2 o'clock.

Instrument transfer rule

Pass instruments handle-first with the working end visible to the operator, maintaining a stable fulcrum. Retrieve the used instrument at the same moment the next is delivered.

Biological sterilization monitor

A spore test using Geobacillus stearothermophilus for steam autoclaves, run at least weekly. It verifies that the sterilization cycle actually killed resistant organisms.

ALARA principle

As Low As Reasonably Achievable means minimizing radiation dose through fast receptors, rectangular collimation, proper technique, and the shortest exposure that still yields a diagnostic image.

Bisecting-angle technique

The receptor is placed close to the tooth, and the central ray is directed perpendicular to the bisector of the angle between the receptor and the tooth's long axis.

Paralleling technique

The receptor is positioned parallel to the tooth's long axis and the central ray is perpendicular to both. A holder is required, and magnification is reduced.

Bitewing angulation

Bitewing central ray is directed at the occlusal plane with about +10 degrees vertical angulation, aimed at the contact area being imaged.

Bass brushing technique

Filaments are angled 45 degrees toward the gingival margin and gently vibrated, then rolled toward the occlusal surface. It cleans the sulcus and interdental areas.

Interdental aid selection

Floss suits tight contacts, interdental brushes suit open embrasures and furcations, and wooden or plastic picks suit Type II embrasures. Selection follows embrasure size.

Fluoride dentifrice amounts

Children under 3 use a smear of 1000 ppm fluoride toothpaste; ages 3 to 6 use a pea-sized amount. Adults use 1000 to 1500 ppm.

Stephan curve

After sucrose exposure, plaque pH falls below the critical value of about 5.5 and returns to baseline in 20 to 60 minutes, depending on saliva flow and buffering.

Xylitol cariostatic dose

About 6 to 10 grams of xylitol daily, divided into three or more exposures, inhibits mutans streptococci. It is non-cariogenic and does not feed acid-producing bacteria.

Cariogenic exposure frequency

Frequency of fermentable carbohydrate intake matters more than total amount. Each exposure produces an acid challenge lasting roughly 20 to 30 minutes.

Dental dam gauge selection

Medium gauge suits routine operative work, heavy gauge suits endodontics and air abrasion, and thin gauge suits severely tapered or sensitive teeth.

Dam clamp types

Winged clamps such as Ivory 8A and 14A anchor posterior molars and premolars. Butterfly or ferrule clamps suit partially erupted teeth and cervical lesions.

Dam removal sequence

Cut the interproximal septa with scissors, remove the dam, then remove the clamp last. Inspect the field and sulcus for retained fragments.

Coronal polishing purpose

Polishing removes extrinsic stain and plaque from the clinical crown only. It does not remove calculus and does not replace scaling.

Coronal polishing contraindications

Avoid polishing newly erupted teeth with immature enamel, hypocalcified enamel, exposed dentin or cementum, and teeth within one month of fluoride or sealant application.

Fluoride varnish concentration

Five percent sodium fluoride varnish contains about 22,600 ppm fluoride. It sets on contact with saliva and remains active for four to six hours.

APF restoration contraindication

Acidulated phosphate fluoride etches porcelain, composite, and glass ionomer restorations. Neutral sodium fluoride is used instead when those materials are present.

Fluoride probable toxic dose

The probable toxic dose is 5 mg of fluoride per kg of body weight. Calculate by patient weight and follow the office ingestion protocol.

Alginate setting variables

Cooler water lengthens working and setting time; warmer water shortens them. Follow the manufacturer's water-to-powder ratio because excess water weakens the set.

Alginate dimensional stability

Alginate loses accuracy through syneresis and imbibition. Pour within 10 to 15 minutes or store the impression in a sealed humid bag.

Tofflemire band orientation

The band's smaller circumference seats gingivally, and the retainer is placed from the buccal with its diagonal slot directed toward the gingiva.

Wedge function

A wedge separates adjacent teeth to compensate for band thickness, presses the matrix against the gingival margin, and prevents restorative overhang.

Calcium hydroxide liner

A bactericidal liner that stimulates tertiary dentin formation. It is placed in small amounts over the deepest area because of low compressive strength.

ZOE and composite interaction

Zinc oxide-eugenol bases inhibit polymerization of resin composite. They are used beneath amalgam but never beneath composite restorations.

Enamel etch endpoint

After 15 to 30 seconds of phosphoric acid, rinse thoroughly and dry until enamel appears frosty white. This indicates a suitable surface for bonding.

Total-etch dentin moisture

After etching and rinsing, dentin should remain visibly moist but not wet so the collagen network does not collapse. Enamel should stay dry.

Sealant isolation requirement

A dry field from etching through curing is the critical variable for sealant retention. Saliva contamination requires re-etching before the sealant is placed.

Sealant etching time

Permanent enamel is etched 15 to 30 seconds with 35 to 37 percent phosphoric acid, rinsed 10 to 15 seconds, and dried until chalky white.

Carbamide peroxide conversion

Carbamide peroxide releases about one-third of its weight as hydrogen peroxide. A 10 percent carbamide gel yields roughly 3 percent hydrogen peroxide.