NHRA Dentist Exam key terms

A predominantly white patch or plaque on the oral mucosa that cannot be rubbed off and cannot be classified clinically or histologically as any other definable lesion.

A fiery red patch of oral mucosa that cannot be attributed to any other identifiable cause and carries a high risk of severe dysplasia or carcinoma.

Disordered maturation and architectural change of epithelium, graded mild to severe, indicating increased risk of malignant transformation but not itself invasive cancer.

Full-thickness epithelial atypia confined by the basement membrane, without invasion of underlying connective tissue; a pre-invasive stage of squamous cell carcinoma.

Removal of a representative sample of a lesion, including the most suspicious area and adjacent normal tissue, for histopathological diagnosis without removing the whole lesion.

Complete removal of a lesion with a margin of normal tissue for both diagnosis and treatment, appropriate for small lesions where total removal is feasible.

Sampling of cells from a palpable mass or fluid-filled lesion using a thin needle and syringe, useful for assessing salivary gland and neck swellings before surgery.

A developmental cyst of the jaws with a thin corrugated parakeratinised lining and high recurrence rate, often occurring in the posterior mandible and associated with naevoid basal cell carcinoma syndrome.

A locally aggressive benign epithelial odontogenic tumour of the jaws, most often in the posterior mandible, that can cause marked expansion and requires wide resection to prevent recurrence.

Inflammation of the dental pulp, described as reversible when provoked pain subsides after stimulus removal or irreversible when pain is spontaneous, prolonged, or persistent.

The distance from a coronal reference point to the intended apical limit of root canal preparation and obturation, usually the apical constriction.

An electronic device that measures electrical impedance between the file and apical tissues to indicate the position of the file tip relative to the apical foramen.

Three-dimensional sealing of the prepared canal space with a core material, typically gutta-percha, and a sealer to prevent microleakage and reinfection.

Inflammation of the tissues around the root apex, usually caused by bacterial infection from a necrotic pulp, presenting as tenderness, pain on biting, or a periapical radiolucency.

The anatomical line where the enamel of the crown meets the cementum of the root, an important landmark for assessing attachment loss and planning restorations.

The distance in millimetres from the gingival margin to the base of the gingival sulcus or pocket, measured with a periodontal probe at six sites per tooth.

The distance from a fixed reference point, usually the cementoenamel junction, to the base of the periodontal pocket, reflecting cumulative attachment loss.

A sign of gingival inflammation recorded when gentle probing provokes bleeding; its absence at repeated visits indicates a low risk of periodontal disease progression.

Removal of plaque and calculus deposits above the gingival margin using hand instruments or ultrasonic devices, forming part of cause-related periodontal therapy.

Direct structural and functional connection between living bone and the surface of a load-bearing implant, without intervening soft tissue.

Progressive reduction in the volume and height of alveolar bone after tooth extraction, continuing over time and affecting the fit and stability of removable prostheses.

The vertical relationship of the maxilla and mandible when the teeth or occlusion rims are in contact, recorded to establish the height of prosthetic restorations.

A maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their discs, independent of tooth contact and reproducible for recording jaw relations.

A local anaesthetic injection near the mandibular foramen that anaesthetises the inferior alveolar nerve, providing pulpal and soft tissue anaesthesia for mandibular posterior teeth.

Localised alveolar osteitis after extraction, with severe throbbing pain, an empty socket and exposed bone, caused by loss of the blood clot without infection.

The upper limit of local anaesthetic drug, calculated by body weight and expressed in milligrams, that may be safely administered to avoid systemic toxicity.

A vasoconstrictor added to local anaesthetic solutions to reduce bleeding, prolong anaesthesia and slow systemic absorption, thereby lowering toxicity risk.

Acute life-threatening insufficiency of cortisol, often triggered by infection or dental surgery in a patient on long-term steroids, presenting with hypotension, weakness and collapse.

A severe, rapidly developing systemic hypersensitivity reaction with airway swelling, bronchospasm and hypotension, requiring immediate intramuscular adrenaline and emergency support.

A written, rehearsed practice procedure specifying team roles, equipment, drugs and escalation steps for managing emergencies such as syncope, anaphylaxis or cardiac arrest.

Cleaning hands with soap and water or alcohol-based rub at defined moments to remove transient microorganisms and reduce cross-infection between patients and staff.

Accidental percutaneous exposure to a needle or other contaminated sharp, requiring immediate wound care, source assessment and post-exposure prophylaxis decisions.

Voluntary agreement to treatment given by a competent patient after receiving adequate information about the nature, benefits, risks and alternatives, documented in the record.

The professional duty to protect patient information from unauthorised disclosure, sharing it only with consent or where required by law or overriding public interest.

The regulatory standard requiring a clinician to have sufficient health, competence and professional conduct to provide safe care without risk to patients.

The range of clinical activities a dental professional is trained, competent and authorised to perform within their registration and local regulations.

A high-concentration topical fluoride preparation applied to tooth surfaces to remineralise enamel and reduce caries incidence, especially in high-risk patients.

Systematic evaluation of patient factors such as diet, plaque, fluoride exposure and past caries to predict future disease and tailor preventive care.

Controlled adjustment of fluoride concentration in public drinking water to a level that reduces dental caries across a population.