NBDHE flashcards

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

Oblique periodontal fibers

The most numerous principal fibers of the periodontal ligament; they run obliquely from cementum downward and inward to alveolar bone and resist axially directed forces on the tooth.

Enamel inorganic content

Mature enamel is about 96% inorganic by weight, primarily hydroxyapatite, with roughly 1% organic material and 3% water, making it the most highly mineralized tissue in the body.

Red complex bacteria

The red complex comprises Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, a bacterial cluster strongly associated with established periodontitis and deep periodontal pockets.

Streptococcus mutans role

The principal cariogenic bacterium that initiates coronal caries by adhering to enamel, producing acid from sucrose, and synthesizing extracellular glucans within dental plaque biofilm.

Amide versus ester anesthetics

Amide local anesthetics such as lidocaine are metabolized in the liver and rarely cause allergy; esters such as procaine are hydrolyzed by plasma pseudocholinesterase and more often provoke allergic reactions.

Maximum lidocaine dose

For a healthy adult, 2% lidocaine with 1:100,000 epinephrine is limited to 4.4 mg/kg and not more than 300 mg total, which equals about eight 1.8-mL cartridges.

Parathyroid hormone calcium effect

Parathyroid hormone raises serum calcium by increasing renal tubular reabsorption, promoting bone resorption, and stimulating renal activation of vitamin D, while calcitonin produces the opposite effect.

Trigeminal nerve divisions

The fifth cranial nerve divides into ophthalmic, maxillary, and mandibular branches; the mandibular division is motor to the muscles of mastication and carries sensation from the lower teeth.

Primary tooth eruption timing

The mandibular central incisor is typically the first primary tooth, erupting around 6 to 10 months; all 20 primary teeth are usually present by about 30 months of age.

Dentin composition

Dentin is approximately 70% inorganic hydroxyapatite, 20% organic material that is mostly type I collagen, and 10% water by weight, making it softer than enamel.

Vitamin C deficiency oral signs

Scurvy from ascorbic acid deficiency impairs collagen synthesis and produces swollen bleeding gingiva, delayed wound healing, and loosened teeth; it resolves with vitamin C repletion.

Gracey curet cutting edge

Area-specific Gracey curets have one cutting edge and a curved, offset blade; the lower edge is adapted at roughly 70 to 80 degrees to the tooth surface during scaling.

Healthy sulcus depth

A clinically healthy gingival sulcus probes from 1 to 3 mm; depths of 4 mm or more accompanied by bleeding on probing suggest inflammation and possible attachment loss.

Clinical attachment level

Clinical attachment level equals probing depth plus the distance from the gingival margin to the cementoenamel junction, and it measures true periodontal support loss over time.

Bitewing radiograph purpose

Bitewing images show the crowns of maxillary and mandibular posterior teeth on one image and are used mainly to detect interproximal caries and crestal bone levels.

ALARA radiation principle

As Low As Reasonably Achievable means every radiograph must be justified by clinical need and exposure is minimized with fast film or digital sensors, collimation, and accurate technique.

Fluoride varnish concentration

Five percent sodium fluoride varnish contains about 22,600 ppm fluoride and is applied in small amounts to dried teeth; it sets on contact with saliva and prevents caries.

Sealant etching time

Permanent teeth are etched about 15 to 20 seconds and primary teeth about 30 seconds with phosphoric acid before sealant placement; the surface must stay dry and uncontaminated until cured.

Furcation involvement classes

Glickman class I is incipient, class II is partial through-and-through, class III is complete through-and-through, and class IV has gingival recession that exposes the furcation clinically.

Syncope management

Vasovagal syncope, the most common dental emergency, is managed by placing the patient supine with legs elevated, loosening tight clothing, and giving oxygen while monitoring vital signs.

Normal adult blood pressure

Normal blood pressure is less than 120/80 mm Hg; 130-139/80-89 mm Hg is stage 1 hypertension, and elective dental care is usually deferred above 180/110 mm Hg.

O'Leary plaque control record

The plaque control record divides the number of tooth surfaces with plaque by the total surfaces examined and multiplies by 100; a score of 20% or less is generally acceptable.

Incidence versus prevalence

Incidence counts new cases arising in a population over a defined period; prevalence counts all existing cases at one point, so longer disease duration raises prevalence without changing incidence.

Sensitivity of a screening test

Sensitivity is the proportion of people who truly have disease and test positive, calculated as true positives divided by true positives plus false negatives.

Cohort study design

A cohort study follows exposed and unexposed groups forward in time to compare disease occurrence, allowing direct calculation of incidence and relative risk.

Case-control study design

A case-control study identifies people with disease and comparable controls without it, then looks back at past exposures; it yields odds ratios and is efficient for rare diseases.

Primary prevention example

Primary prevention acts before disease begins, such as community water fluoridation, dental sealants, and immunization, whereas secondary prevention detects and treats disease in its early stages.

Optimal water fluoride level

The recommended concentration of fluoride in community drinking water is 0.7 mg/L, a level that reduces caries while keeping the risk of dental fluorosis low.

Epidemiologic triad

The epidemiologic triad describes disease as the interaction of a susceptible host, an agent such as bacteria, and an environment that permits exposure, as in dental caries.

DMFT index

The DMFT index counts decayed, missing due to caries, and filled permanent teeth per person; the mean score summarizes caries experience in a population.

Relative risk interpretation

Relative risk is incidence in the exposed divided by incidence in the unexposed; a value of 1.0 means no association, above 1.0 increased risk, and below 1.0 a protective effect.

Confounding variable

A confounding variable is associated with both the exposure and the outcome but is not on the causal pathway, so it can distort the observed association unless controlled by design or analysis.