Dental Hygienist Licensing Exam flashcards

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

Hydroxyapatite

Crystalline calcium phosphate mineral, Ca10(PO4)6(OH)2, that forms the inorganic matrix of enamel, dentin, and cementum and is susceptible to acid dissolution.

Enamel composition

Mature enamel is about 96% inorganic mineral by weight, mainly carbonated hydroxyapatite, with little water and organic material and no living cells.

Dentin collagen

Dentin organic matrix is predominantly type I collagen, which provides tensile strength and supports the mineralized tissue; dentin is about 70% inorganic by weight.

Periodontal ligament

Fibrous connective tissue between cementum and alveolar bone that attaches the tooth, transmits occlusal forces, and contains proprioceptive nerve endings and blood vessels.

Gingival sulcus

Space between the free gingival margin and the tooth surface bounded by sulcular epithelium; clinically healthy depth is generally 1–3 mm.

Dental biofilm

Structured microbial community attached to tooth surfaces and embedded in an extracellular matrix; supragingival plaque is associated with caries and gingivitis.

Critical plaque pH

Approximately 5.5; below this value enamel hydroxyapatite begins to dissolve, and repeated acid challenges shift the balance toward demineralization.

Fluorapatite

Mineral formed when fluoride substitutes for hydroxyl in hydroxyapatite, making enamel less soluble in acid and more resistant to caries.

Salivary buffer capacity

Ability of saliva, mainly via bicarbonate, to neutralize dietary and bacterial acids; stimulated saliva has higher flow and buffering capacity than resting saliva.

Alveolar bone resorption

Loss of bone supporting the teeth caused by host inflammatory and immune responses to periodontal biofilm; it follows clinical attachment loss and appears radiographically as reduced bone height.

Tooth eruption chronology

Primary teeth begin erupting around 6 months; permanent first molars and central incisors around 6–7 years; canines 11–12; third molars 17–21.

Clinical attachment loss

Distance from the cementoenamel junction to the base of the periodontal pocket; calculated as probing depth plus recession minus gingival margin position.

Universal curet

Periodontal instrument with a rounded toe and two cutting edges per working end, used for subgingival scaling and root planing in any area.

Gracey curet

Area-specific periodontal curet with one cutting edge and an angled blade; each number is designed for a particular tooth surface or sextant.

Sickle scaler

Instrument with a pointed tip and two cutting edges, designed for supragingival calculus removal; it is not adapted to subgingival root surfaces.

Instrument angulation

Angle between the instrument blade face and tooth surface; 45–90 degrees is correct for scaling, while 0 degrees adapts and more than 90 degrees can gouge cementum.

Fluoride varnish concentration

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

Sealant mechanism

Resin sealant bonds to acid-etched enamel by micromechanical retention, physically blocking plaque and carbohydrate from pits and fissures.

Standard precautions

Infection-control practices treating all blood, saliva, and body fluids as potentially infectious; they include hand hygiene, gloves, masks, eye protection, and safe sharps handling.

Autoclave sterilization

Steam under pressure at 121°C and 15 psi for 15–20 minutes, or 134°C for 3–4 minutes, kills spores and achieves sterilization when packaging and load are correct.

Ultrasonic scaling

Piezoelectric or magnetostrictive tip vibration removes calculus and biofilm; light pressure and continuous water lavage prevent heat damage and improve visibility.

Stage 1 hypertension

Systolic 130–139 or diastolic 80–89 mmHg according to ACC/AHA; values of 180/120 mmHg or higher with symptoms require urgent medical evaluation before elective care.

Incidence

Number of new cases of a disease in a population during a specified period, divided by the population at risk; it measures risk of developing disease.

Prevalence

Proportion of a population with a disease at a given time or over a period; it reflects both incidence and disease duration.

Sensitivity

Proportion of truly diseased people whom a test correctly identifies as positive; calculated as true positives divided by true positives plus false negatives.

Specificity

Proportion of truly disease-free people whom a test correctly identifies as negative; calculated as true negatives divided by true negatives plus false positives.

Positive predictive value

Probability that a person with a positive test truly has the disease; it rises with disease prevalence and falls when prevalence is low.

DMFT index

Count of decayed, missing, and filled permanent teeth per person; the lowercase dmft applies the same counting to primary teeth.

Relative risk

Ratio of disease incidence in exposed people to incidence in unexposed people; a value of 1.0 indicates no association.

Levels of prevention

Primordial prevents risk factors; primary prevents disease onset; secondary detects and treats early disease; tertiary limits disability and restores function.

Randomized controlled trial

Study assigning participants randomly to intervention or control groups; randomization balances confounders and supports causal inference better than observational designs.

Reliability versus validity

Reliability is consistency or repeatability of measurements; validity is whether a measurement actually reflects the intended construct.