NZ Dental Technician REX flashcards

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

FDI tooth numbering

Two-digit system: first digit is the quadrant (1-4 permanent, 5-8 primary), second digit is the tooth position from the midline (1-8).

Cusp of Carabelli

An accessory cusp on the mesiolingual surface of the maxillary first permanent molar, most common in European populations; useful for identifying the tooth.

Centric relation

A maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their discs, in the anterior-superior position against the articular eminences.

Freeway space

The difference between vertical dimension at rest and at occlusion, typically 2-4 mm; used when setting denture tooth height.

Gamma-2 phase

The tin-mercury phase (Sn7-8Hg) in set dental amalgam; it is the weakest and most corrosion-prone phase and is reduced by high-copper alloys.

C-factor

Ratio of bonded to unbonded surface area in a cavity; high C-factor increases polymerisation shrinkage stress because contraction cannot be relieved.

Transformation toughening

Mechanism in zirconia where stress-induced tetragonal-to-monoclinic transformation creates compressive stress that arrests crack propagation and increases toughness.

Neutral zone

The potential space between tongue and cheeks where forces are balanced; denture teeth and polished surfaces placed here improve stability.

Kennedy Class I

Bilateral edentulous areas located posterior to the remaining natural teeth; a tooth-tissue-supported removable partial denture design is typical.

Applegate's rules

Rules for classifying partially edentulous arches: classify after extractions, let the most posterior edentulous area govern, and exclude third molars not to be replaced.

Indirect retainer

A component of a removable partial denture that resists displacement of the denture base away from the tissue, usually via rests on teeth anterior to the fulcrum line.

Marginal fit gap

The discrepancy between crown margin and tooth preparation; clinically acceptable values are typically under 120 micrometres for fixed restorations.

Platform switching

Use of a smaller-diameter abutment on a wider implant platform; shifts the implant-abutment junction medially and reduces crestal bone loss.

Sanitary pontic

A pontic design with a convex tissue surface that contacts the ridge minimally, allowing cleaning; preferred for posterior bridges.

Silane coupling agent

A primer applied to etched ceramic that forms covalent bonds between the silica surface and resin cement, improving bond strength of veneers.

Adams clasp

A removable orthodontic clasp with two arrowheads engaging mesiobuccal and distobuccal undercuts of a molar, providing retention for active plates and retainers.

ANB angle

Cephalometric angle formed by SNA minus SNB; values of 2-4 degrees indicate skeletal Class I, higher values suggest Class II.

Temporary anchorage device

A miniscrew or miniplate placed in bone to provide absolute anchorage for orthodontic tooth movement without relying on patient compliance.

Spaulding classification

Classifies items as critical, semi-critical, or non-critical based on infection risk, guiding whether sterilisation or disinfection is required.

Biological indicator

A spore test (Geobacillus stearothermophilus for steam) used to verify steriliser efficacy; the most reliable routine sterilisation monitoring method.

Standard precautions

Infection control measures applied to all patients regardless of known infection status, including hand hygiene, PPE, and safe sharps handling.

Crystalline silica hazard

Airborne dust from trimming plaster and investment; inhalation causes silicosis, so wet trimming and local exhaust extraction are required.

Amalgam separator

A device fitted to laboratory or surgery sinks that captures amalgam waste before it enters the wastewater system, reducing environmental mercury.

Local exhaust ventilation

Engineering control that captures airborne contaminants such as monomer vapour or dust at the source before they enter the breathing zone.

HPCA Act 2003

New Zealand legislation establishing the Health Practitioners Competence Assurance framework, under which the Dental Council registers and sets standards for technicians.

Te Tiriti o Waitangi

The Treaty of Waitangi; its principles of partnership, participation, and protection underpin culturally safe practice in New Zealand health services.

Privacy Act 2020

New Zealand law governing collection, use, storage, and disclosure of personal information, including health information, with mandatory breach notification.

Scope of practice

The defined activities a registered practitioner is competent and authorised to perform; dental technicians fabricate appliances on prescription and do not diagnose patients.

FIFO stock rotation

First-in, first-out inventory practice that uses older stock first, reducing waste from expired alginate, plaster, investment, and resin materials.

Device traceability

The record linking a finished prosthesis to its patient, prescription, material batch, and technician, enabling recall if a defect is found.

Trueness versus precision

Trueness is closeness of a measurement to the true value; precision is the closeness of repeated measurements to each other; both matter for scanner accuracy.

STL file format

Standard tessellation language; a surface mesh format of triangles widely used for digital impression, CAD design, and 3D printing in dentistry.