ADC Written Exam (Dental Hygiene) key terms

The hard, highly mineralised layer covering the crown of a tooth. It is almost entirely mineral, has no living cells and cannot regrow, so tissue lost to decay or wear is replaced only with restorative material.

The mineralised tissue forming most of the tooth beneath enamel and cementum. Fine tubules run through it to the pulp, which is why exposed dentine is sensitive and decay spreads quickly once it reaches this layer.

The soft tissue inside the tooth containing nerves, blood vessels and connective cells. It keeps the tooth vital, senses stimuli and mounts an inflammatory response that causes pain when irritated by decay, trauma or drilling.

A band of collagen fibres that anchors the tooth root in its bony socket and cushions chewing forces. It carries nerve endings that give tactile feedback and vessels that supply the root surface.

The bone of the upper and lower jaws that surrounds and supports the tooth roots. It remodels constantly in response to loading and resorbs after tooth loss or in advanced periodontal disease.

A structured community of bacteria held in a sticky polymer matrix on tooth and restoration surfaces. Its firm adhesion and resistance to rinsing make it the main cause of caries and periodontal disease.

A bacterium commonly found in dental plaque that ferments sugars into acid and builds sticky glucans from sucrose. It is strongly linked with the beginning and progression of dental decay.

Fluid produced by the major and minor salivary glands that lubricates the mouth, buffers acids, clears food, supplies minerals for repair of enamel and carries digestive enzymes and antibodies.

The fifth cranial nerve, which carries sensation from the face, teeth and mouth and supplies the chewing muscles. Its maxillary and mandibular divisions are the main pathways targeted in dental local anaesthesia.

A drug that reversibly blocks nerve conduction by interfering with sodium channels, numbing a region while the patient stays conscious. In dentistry it is usually combined with a vasoconstrictor to lengthen its effect.

An agent added to local anaesthetic solutions that narrows blood vessels and slows removal of the drug from the injection site. This prolongs numbness, limits bleeding and reduces the risk of toxic blood levels.

Antibiotics given before a procedure to lower the chance that bacteria entering the bloodstream will cause infection elsewhere, such as on a damaged heart valve. It is reserved for specific high-risk patients, not routine care.

The body's process of stopping bleeding through vessel narrowing, platelet plug formation and blood clotting. It is assessed before surgery because anticoagulant medicines and bleeding disorders can impair it.

A disease in which acids produced by plaque bacteria fermenting sugars demineralise tooth tissue over repeated cycles. It starts as white-spot lesions and can progress to cavitation, pulp involvement and tooth loss.

Reversible inflammation of the gums caused by plaque accumulation, shown by redness, swelling and bleeding when probed gently. It is treated by removing biofilm and teaching the patient effective daily oral hygiene.

A chronic inflammatory disease in which plaque bacteria drive destruction of the periodontal ligament and alveolar bone, producing pockets, attachment loss and possible tooth loss. Smoking and diabetes increase the risk.

The distance from the gum margin to the base of the sulcus or pocket, measured with a calibrated probe. Increased depth alongside bleeding and attachment loss indicates periodontal disease and guides treatment planning.

A procedure that removes inflamed or infected pulp, cleans and shapes the canal system, then seals it with filling material. It aims to keep a tooth that would otherwise need extraction.

A latex or non-latex sheet held over the teeth by a clamp that separates the working field from saliva and tongue. It improves visibility, protects the airway and keeps root canal work clean.

The direct, stable union between living bone and the surface of a dental implant, with no soft tissue in between. It is the biological basis for implant-supported crowns, bridges and dentures.

A system that describes a patient's bite by the relationship of the first permanent molars, giving Class I, II and III patterns. It is used to record and communicate how the teeth and jaws meet.

A method of sealing decay in a primary molar by cementing a preformed metal crown over the tooth without drilling or local anaesthesia. Sealing starves the bacteria and usually stops the lesion progressing.

Removal of the inflamed coronal portion of the pulp while leaving the root pulp alive, typically in a primary or young permanent molar. It aims to keep the tooth vital and symptom-free.

A group of conditions affecting the jaw joints and chewing muscles that cause pain, clicking, limited opening or headache. Management usually begins with conservative measures such as advice, soft diet and exercises.

An intraoral X-ray showing the crowns of upper and lower teeth on one image together with the bone crest. It is used mainly to detect decay between teeth and to monitor bone levels.

A patient's voluntary agreement to treatment after understanding the diagnosis, options, likely benefits, risks and costs. It must be obtained before care begins and the discussion recorded in the clinical notes.

A person's ability to understand information relevant to a decision, weigh it up and communicate a choice. Adults are presumed capable; if not, the law and substitute decision-makers guide treatment.

The professional duty to keep patient information private and share it only with people who need it for care, or where legislation requires or permits disclosure.

A collaborative, person-centred counselling style that helps patients identify their own reasons for change, such as quitting smoking or improving oral hygiene, instead of being instructed or warned.

A psychological model proposing that people take preventive action when they believe they are susceptible, that the condition is serious, that the action helps and that barriers are manageable.

The limits that keep the clinician-patient relationship safe and focused on care. They cover personal involvement, gifts, social media contact, and treating friends or relatives.

The legal obligation in many jurisdictions for health professionals to tell the relevant authority about suspected child abuse, neglect or other notifiable harm, even without the family's agreement.

The range of duties a practitioner is trained, competent and legally permitted to perform in their registered role. Working beyond it, even with good intentions, is unsafe and unprofessional.

Adjusting the fluoride level of a community water supply to a concentration that reduces decay across the whole population. It is safe, inexpensive and does not rely on individual behaviour.

A concentrated fluoride coating painted onto teeth by a clinician to harden enamel and slow decay, especially in children and higher-risk patients. It sets on contact with saliva and is reapplied at intervals.

A count of decayed, missing and filled teeth used to express caries experience in the permanent (DMFT) or primary (dmft) dentition. It allows comparison between groups and tracks change over time.

A structured review of factors such as diet, fluoride exposure, plaque control, saliva, past decay and medical history to estimate the likelihood of new lesions and plan preventive care.

Infection control measures applied to every patient whatever their known infection status, including hand hygiene, gloves, eye protection, safe sharps handling and proper instrument sterilisation.

The planned time between routine examinations, chosen for each patient according to disease risk and need rather than applying one fixed schedule to everyone.

Practice that recognises a patient's cultural identity and history, particularly for Aboriginal and Torres Strait Islander peoples, and delivers care that is respectful, accessible and free of discrimination.