Jordan Dental Exam key terms

The basic structural unit of enamel, a tightly packed column of hydroxyapatite crystallites running from the dentinoenamel junction toward the tooth surface, whose decussation and orientation determine how caries spreads and how cavity preparations are shaped.

The scalloped interface where enamel meets dentine. Its irregular outline resists shear forces and slows caries progression, and it is the landmark used to judge whether a restoration margin sits in enamel or dentine.

A microscopic channel running through dentine from the pulp to the dentinoenamel junction, containing an odontoblast process and fluid. Outward fluid movement in open tubules is the accepted explanation of dentine hypersensitivity.

The layer of crushed mineral and denatured collagen debris produced on cut dentine or enamel by burs and hand instruments. It blocks tubules and reduces permeability; its removal or retention affects bonding and postoperative sensitivity.

The zone created when resin infiltrates acid-etched demineralised dentine and polymerises around exposed collagen fibrils. Its quality and thickness are the main determinants of dentine bond strength and seal.

An adhesive strategy in which phosphoric acid is applied first, rinsed away, and followed by primer and bonding resin. It removes the smear layer and relies on complete resin infiltration of demineralised dentine to form a hybrid layer.

The ratio of bonded to unbonded surface area in a cavity preparation. High configuration factors restrict resin flow and increase polymerisation shrinkage stress, so deep narrow preparations are filled incrementally.

The distance from a coronal reference point to the apical constriction or desired instrumentation limit, established radiographically and by apex locator. It guides canal preparation and prevents over- or under-instrumentation.

The narrowest point of the root canal, usually just short of the radiographic apex, marking the transition from canal to periapical tissue. It is the anatomical target for cleaning, shaping, and obturation.

A device that measures electrical impedance between a file in the canal and a lip clip to estimate the apical constriction. It improves working length accuracy when the apex is unclear on radiographs.

Debris film of organic and inorganic particles created on canal walls by instrumentation. It may harbour bacteria and block dentinal tubules; irrigation with chelators such as EDTA removes it during chemomechanical preparation.

The primary endodontic irrigant, used for its antimicrobial action and ability to dissolve necrotic pulp tissue. Its concentration is balanced against tissue toxicity, and extrusion beyond the apex can cause severe complications.

The vertical relationship of the maxilla and mandible when the teeth or occlusion rims are in contact. It is assessed at rest and in occlusion and guides denture construction and full-mouth rehabilitation.

The difference between the mandibular rest position and maximum intercuspation, typically two to four millimetres. It is used to judge whether an occlusal vertical dimension is acceptable.

A maxillomandibular relationship in which the condyles sit in their most anterior, superior position against the articular eminence, independent of tooth contact. It is a repeatable reference for mounting casts and recording jaw relations.

The principle that the total periodontal ligament area of the abutment teeth supporting a fixed partial denture should equal or exceed that of the teeth being replaced. It guides bridge design and abutment selection.

A tooth, implant, or root that supports and retains a fixed or removable prosthesis. Its periodontal support, angulation, and crown-root ratio determine how much load it can bear.

Joining two or more teeth or implants with a rigid or semi-rigid restoration to distribute occlusal forces and stabilise mobile teeth. It is used in periodontal therapy and in replacing missing teeth.

Passing a periodontal probe through the gingival sulcus under local anaesthesia to the alveolar crest to measure attachment loss and detect intrabony defects. It supports periodontal diagnosis and surgical planning.

The distance from the cementoenamel junction to the base of the periodontal pocket. Unlike probing depth, it accounts for gingival recession and is the standard measure of past periodontal destruction.

The distance from the gingival margin to the base of the sulcus or pocket, measured with a calibrated probe. It indicates current pocket depth but must be interpreted with recession and attachment level.

A surgical technique placing a barrier membrane over a periodontal or implant defect to exclude epithelial and connective tissue cells while slower-forming bone and periodontal ligament repopulate the space.

Death of irradiated bone, most often the mandible, after radiotherapy. Poor healing, exposed bone, and pain develop spontaneously or after trauma or extraction; prevention includes pre-radiotherapy dental clearance and hyperbaric oxygen in selected cases.

Exposed bone in the maxillofacial region persisting for more than eight weeks in a patient taking antiresorptive or antiangiogenic drugs, with no history of radiotherapy. Extractions are a common trigger.

A drug that inhibits osteoclast-mediated bone resorption, used for osteoporosis and malignancy-related bone disease. Long duration and intravenous use raise the risk of medication-related osteonecrosis of the jaw after oral surgery.

A predominantly white patch or plaque that cannot be characterised clinically or pathologically as any other disease. It is a diagnosis of exclusion and carries a risk of dysplasia and malignant transformation.

A fiery red patch that cannot be attributed to any other definable lesion. It has a higher rate of dysplasia and carcinoma in situ than leukoplakia and warrants biopsy.

Disordered epithelial maturation with cytological atypia, graded mild, moderate, or severe. It is a precancerous change; severe dysplasia and carcinoma in situ require excision or close follow-up.

A group of inherited defects of enamel formation affecting primary and permanent dentition, classified as hypoplastic, hypomaturation, or hypocalcified. Restorations must address poor bonding and rapid wear.

An inherited disorder of dentine formation, often associated with osteogenesis imperfecta, producing opalescent teeth with bulbous crowns, obliterated pulp chambers, and fragile roots. Restorative and prosthodontic management is usually required.

A five-point radiographic scale for grading periapical health from intact periodontium to severe apical periodontitis. It standardises reporting in endodontic outcome studies and clinical records.

A volumetric imaging method producing three-dimensional reconstructions from a cone-shaped X-ray beam. It is used for implant planning, impacted teeth, and complex root anatomy, with dose lower than medical CT.

A line drawing of landmarks on a lateral skull radiograph used to measure skeletal and dental relationships. It supports orthodontic diagnosis, growth assessment, and treatment planning.

The stage of a child's bone development, estimated from hand-wrist radiographs or cervical vertebral shape. It predicts the pubertal growth spurt and the best timing for growth-modifying orthodontic treatment.

Injection of local anaesthetic near the apex of a tooth to block terminal nerve branches. It works well in the maxilla but is less reliable in dense mandibular bone, where a block is often preferred.

A mandibular nerve block depositing anaesthetic near the mandibular foramen to anaesthetise the inferior alveolar nerve. Failure is common when the target is missed or accessory innervation is present.

The upper limit of local anaesthetic, expressed in milligrams per kilogram or as a cartridge count, that may be given safely. It is calculated from patient weight and the drug's concentration before injection.

Sterilisation using saturated steam under pressure, typically at 121 degrees Celsius or 134 degrees Celsius. It is the preferred method for heat-stable instruments; effectiveness requires correct packaging, loading, and cycle monitoring.

A test strip or vial containing highly resistant bacterial spores used to verify that a sterilisation cycle achieved kill. It is the most reliable routine check of autoclave performance.

A scheme dividing instruments into critical, semicritical, and noncritical categories according to contact with sterile tissue, mucosa, or intact skin. It determines whether sterilisation, high-level disinfection, or cleaning is required.

A patient's voluntary agreement to treatment after receiving adequate information about diagnosis, options, material risks, and consequences of refusal. It must be documented and obtained before care begins.

The ethical and legal duty to protect patient information from unauthorised disclosure. It may be breached only with consent or where law requires, for example in reporting certain communicable diseases.

Creating and retaining accurate clinical notes, radiographs, consent forms, and correspondence for the period required by law or regulation. Records support continuity of care and are evidence in complaints or litigation.

Contraction of resin composite as monomer converts to polymer, creating stress at the tooth-restoration interface. It can cause marginal gaps, postoperative sensitivity, and recurrent caries; incremental placement and low-shrinkage materials reduce it.