ADC Written Exam (Dental Hygiene) cheat sheet

Enamel is about 96% inorganic hydroxyapatite by weight; dentine is about 70% inorganic, 20% organic (mainly type I collagen) and 10% water.

Critical pH: enamel demineralizes below about 5.5; root dentine and cementum below about 6.2-6.7; resting plaque pH is roughly 6.5-7.0.

Normal salivary flow is 0.5-1.5 L/day; stimulated parotid saliva is bicarbonate-rich and buffers acid, raising oral pH.

Salivary parasympathetic supply: facial nerve (chorda tympani) to submandibular and sublingual glands; glossopharyngeal nerve (auriculotemporal) to the parotid gland.

Periodontal ligament principal fibres: alveolar crest, horizontal, oblique (most numerous; resist axial load), apical and interradicular.

Red complex periodontal pathogens: Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola.

Local anaesthetic limits in a healthy adult: lidocaine with adrenaline about 7 mg/kg (max 500 mg); plain lidocaine 4.4 mg/kg (max 300 mg); articaine about 7 mg/kg (max 500 mg).

Infective endocarditis prophylaxis is reserved for highest-risk patients (prosthetic valve, previous infective endocarditis, certain congenital heart disease), not routine mitral valve prolapse.

Vitamin D (calcitriol) increases intestinal calcium absorption; parathyroid hormone raises serum calcium; calcitonin lowers serum calcium.

G.V. Black cavity classification: Class I pits/fissures, Class II proximal posterior, Class III proximal anterior, Class IV proximal anterior involving incisal edge, Class V cervical.

Composite resin is placed in increments of 2 mm or less to ensure adequate light curing; cure depth depends on shade, opacity and light intensity.

Endodontic working length terminates at the apical constriction, typically 0.5-1 mm short of the radiographic apex.

Sodium hypochlorite 0.5-5.25% is the primary root canal irrigant; 17% EDTA removes the smear layer; both must be confined to the canal.

2018 periodontitis classification: Stage I-IV reflects severity and complexity; Grade A-C reflects rate of progression (bone loss/age, smoking, diabetes).

Periodontal health shows probing depths 3 mm or less with no bleeding on probing; bleeding at 10% or more of sites suggests gingival inflammation.

The Hall technique cements a preformed metal crown over a carious primary molar without tooth preparation; it is indicated for single occlusal or proximal lesions.

Mandibular molars and premolars are anaesthetized by an inferior alveolar nerve block; buccal soft tissue often requires an additional long buccal infiltration.

The first permanent molar erupts at about 6 years and does not replace a primary tooth; the mixed dentition spans roughly 6-12 years.

Four ethical principles: autonomy (respect patient choice), beneficence (do good), non-maleficence (avoid harm) and justice (fair access).

Valid informed consent requires capacity, adequate disclosure, comprehension and voluntariness; consent may be withdrawn at any time.

Transtheoretical model stages: precontemplation, contemplation, preparation, action and maintenance, with relapse possible at any stage.

Motivational interviewing uses OARS: open questions, affirmations, reflections and summaries; it is non-judgemental and avoids confrontation.

Health Belief Model constructs: perceived susceptibility, severity, benefits and barriers, plus cues to action and self-efficacy.

Confidentiality may be breached only with consent, legal requirement or serious risk to the patient or public; suspected child abuse is a mandatory report.

A dental hygienist must practise within the scope of the profession and refer findings outside that scope to a dentist.

Clinical records should be contemporaneous, dated and signed, documenting consent discussions, advice given and any refusal of treatment.

Teach-back confirms understanding by asking the patient to restate instructions in their own words before leaving.

Community water fluoridation is maintained at about 0.7 mg/L; adult toothpaste contains 1000-1500 ppm fluoride, and children under 6 use 1000 ppm in a smear or pea-sized amount.

Fluoride varnish contains 22,600 ppm fluoride (5% sodium fluoride) and is applied at least twice yearly for high caries-risk children.

The DMFT/dmft index counts decayed, missing and filled teeth; ICDAS scores caries visually from 0 (sound) to 6 (extensive cavitation).

Incidence is the number of new cases over a period; prevalence is the total number of existing cases at a given time.

Steam sterilization uses 134°C for 3 minutes or 121°C for 15 minutes at the required pressure, monitored by chemical indicators and spore tests.

The five moments for hand hygiene: before patient contact, before an aseptic task, after body fluid exposure, after patient contact and after touching surroundings.

Sharps injury: wash with soap and water, encourage bleeding, report immediately and assess need for HIV, HBV and HCV post-exposure prophylaxis.

Recall intervals are risk-based; low-risk adults may be reviewed less frequently than high-risk adults or children.

Fissure sealants are indicated for deep pits and fissures in permanent molars of caries-susceptible children, placed after isolation and etching.