Iran Dental Board - Prosthodontics key terms

The prepared boundary at the cervical edge of a tooth or die where the restoration's margin terminates and adapts; its geometry-chamfer, shoulder, or knife-edge-affects fit, strength, and plaque retention.

A circumferential band of sound tooth structure, usually 1.5–2 mm axially, retained between the preparation finish line and the core; it resists lever forces and reduces root fracture in endodontically treated teeth.

The closeness of a restoration's margin to the tooth finish line, assessed by gap width and seating; poor adaptation permits microleakage, cement dissolution, and recurrent caries.

A foundation restoration for a severely damaged endodontically treated tooth, consisting of a dowel retained in the root canal and a core that replaces missing coronal structure to support a crown.

A guideline stating that the total periodontal ligament area of abutment teeth supporting a fixed partial denture should equal or exceed that of the teeth being replaced.

Simultaneous bilateral contact of opposing teeth in centric and eccentric positions, used in complete denture design to stabilize the bases during function and parafunction.

An occlusal scheme with flat occlusal planes and no cuspal inclines, reducing lateral forces and often chosen for severely resorbed ridges or atypical jaw relationships.

The potential space between the lips, cheeks, and tongue where forces from these structures are balanced; denture teeth and polished surfaces are placed there to improve stability.

A slight compression of the denture base along the junction of the hard and soft palates that maintains the posterior seal, reduces gagging, and improves retention of the maxillary complete denture.

Controlled shaping of a custom tray's edges with modeling compound or a similar material during functional movements, recording the vestibular and lingual extensions of a complete denture.

Chronic, progressive loss of alveolar bone and soft tissue after tooth extraction, leading to a reduced denture-bearing area and changes in facial support and occlusion.

A pear-shaped soft-tissue pad at the posterior end of the mandibular ridge, containing glandular and fibrous tissue; it is a key landmark for the posterior extent and occlusal plane of lower dentures.

A clasp assembly using a mesial rest, proximal plate, and I-bar retentive arm; designed to minimize torque on distal-extension abutments while providing retention and reciprocation.

A prepared recess in a tooth surface that accommodates a rest and directs occlusal forces along the long axis of the abutment, providing support and preventing tissue-ward movement of the prosthesis.

Parallel prepared axial surfaces on abutment teeth that guide a removable partial denture to its seat and provide reciprocation and stabilization against horizontal forces.

The rigid component joining the parts of a removable partial denture on each side of the arch; it distributes forces and must be designed to avoid impinging on gingival tissues.

A laboratory procedure in which the distal-extension ridge is recorded in functional form and the master cast is modified, so the denture base intimately contacts the displaced mucosa under load.

Direct structural and functional connection between living bone and the surface of a load-bearing implant, without intervening soft tissue, achieved through biocompatible material and controlled healing.

Use of a prosthetic abutment with a smaller diameter than the implant's coronal opening, shifting the junction inward and possibly preserving crestal bone and soft tissue.

The contour of a restoration as it emerges from the gingival or peri-implant tissue, influencing soft-tissue health, plaque control, and esthetic appearance.

The rotational force measured when seating an implant, used as an indicator of primary stability and to guide decisions about immediate or progressive loading.

A prosthetic extension supported only at one end; it creates bending moments and should be limited in length and load, especially with implants.

A maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their disks, with the complex in the anterior-superior position against the articular eminences; it is independent of tooth contact.

The complete, fully seated contact of opposing teeth when the mandible is closed, independent of condylar position; often coincides with centric occlusion but not necessarily centric relation.

The influence of the lingual surfaces of anterior teeth on mandibular movement, guiding disclusion of posterior teeth in eccentric movements and protecting them from harmful lateral forces.

An occlusal arrangement in which anterior teeth protect posterior teeth in eccentric movements and posterior teeth protect anterior teeth in maximum intercuspation.

The distance between two selected points, usually on the nose and chin, when the teeth or occlusion rims are in maximum intercuspation; it influences facial appearance and function.

A collective term for clinical problems involving the temporomandibular joint, masticatory muscles, or both, characterized by pain, limited or asymmetric movement, and joint sounds.

Contraction that occurs when a resin monomer converts to polymer, producing stress at bonded interfaces, marginal gaps, and possible cusp deflection in composite restorations.

The fractional change in length per unit temperature change; mismatch between a restorative material and tooth can cause microleakage and debonding under thermal cycling.

The maximum stress a material can withstand before fracture in bending; important for brittle ceramics and provisional resins in prosthodontics.

A polycrystalline ceramic used for frameworks, crowns, and implants; it has high strength and toughness, but requires appropriate sintering and surface treatment and can undergo low-temperature degradation.

Selection of a tooth color using shade guides or digital devices under standardized lighting, considering value, chroma, and hue to match adjacent teeth and achieve natural appearance.

The degree to which light passes through a material rather than being absorbed or reflected; it affects the lifelike appearance of ceramics and resin composites.

Capturing the geometry of teeth, implants, and soft tissues with an intraoral scanner to create a digital model, eliminating conventional impression materials and enabling CAD/CAM workflows.

Computer-aided design and computer-aided manufacturing; digital data are used to design a restoration and to produce it by milling or additive manufacturing.

A removable prosthesis that closes a congenital or acquired defect of the hard or soft palate, separating the oral and nasal cavities to restore speech, swallowing, and sometimes facial contour.

Subjective sensation of dry mouth resulting from reduced salivary flow; it increases caries, denture discomfort, and mucosal irritation and is often caused by medications or systemic disease.

Chronic erythematous inflammation of the denture-bearing mucosa, most often palatal, associated with Candida albicans, continuous denture wear, and poor denture hygiene.

A facial prosthesis retained by implants placed in the temporal bone, using bar-clip or magnet attachments; it restores auricular form and is easier to position than adhesive-retained prostheses.