GPT Terms – R

RAD: acronym for Radiation Absorbed Dose, a unit of measurement of the absorbed dose of ionizing radiation. The biologic effect of one rad varies with the type of radiation tissue is exposed to—see also GRAY

radiation : the emission of electromagnetic waves, such as light, short wave, radio, ultraviolet, or x-rays, or particulate rays such as alpha, beta, and gamma rays

radiation carrier : an ancillary prosthesis used to administer radiation to confined areas by means of capsules, beads or needles of radiation emitting materials such as radium or cesium. Its function is to hold the radiation source securely in the same location during the entire period of treatment. Radiation oncologists occasionally request these devices to achieve a close approximation and controlled application of radiation to a tumor deemed amiable to eradication—syn CARRIER PROSTHESIS, INTRACAVITY APPLICATOR, INTRACAVITY CARRIER, RADIATION APPLICATOR, RADIUM CARRIER, RADIOTHERAPY PROSTHESIS

radiation cone locator : an ancillary prosthesis used to direct and reduplicate the path of radiation to an oral tumor during a split course of irradiation—syn CONE LOCATOR, DOCKING DEVICE

radiation shield : a intraoral ancillary prosthesis designed to shield adjacent tissues from radiation during orthovoltage treatment of malignant lesions of the head and neck region—syn LEAD SHIELD, RADIATION STENT, TONGUE PROTECTOR

radiation shield/positioner : a custom made ancillary prosthesis to direct, align, and protect adjacent tissues during irradiation. The shield/positioner will prevent radiation damage to tissues that are unaffected by a tumor

radiation source device : custom made ancillary prosthesis to align a radiation source to a specific anatomic site

radiation source prosthesis: a custom made ancillary prosthesis to align a radiation source to a specific anatomic site. This prosthesis is used to carry or direct a radiation source to a tumor site

radiation stent: see RADIATION SHIELD

rad·i·cle : the lower part of the axis of an object

rad·ic·u·lar : pertaining to the root of a tooth

ra·di·o·gram n: see RADIOGRAPH

1ra·di·o·graph : an image produced on any sensitive surface by means of electromagnetic radiation other than light; a x-ray photograph

2ra·di·o·graph : to make a radiograph of

ra·di·o·lu·cent : permitting the passage of radiant energy with relatively little attenuation by absorption

ra·di·o·paque : a structure that strongly inhibits the passage of radiant energy

ramus endosteal implant : an endosteal dental implant that is attached, in part, to the ramus of the mandible

ramus frame endosteal implant : a dental implant design that consists of a horizontal intraoral supragingival abutment in the form of a bar and endosteal implant body segments that are placed into the rami and symphysis areas as one section (implants fabricated from one piece of metal), or two sections (implants of anterior and horizontal segments that are connected at the time of placement), or five sections (an implant consisting of five sections in which the endosteal implant body segments are independently placed and connected with fitted parts)

range of motion : the range, measured in degrees of a circle, through which a joint can be extended or flexed. The range of the opening, lateral, and protrusive excursions of the temporomandibular joint

ra·phe 1: line of union of symmetrical parts 2: a fibrous band or bands where paired muscles meet

re·at·tach·ment : in periodontics, the reunion of epithelial and connective tissues with root surfaces and bone such as occurs after incision or injury

re·base : the laboratory process of replacing the entire denture base material on an existing prosthesis

receptor sites : specific sites at which molecular binding occurs that results in specific biologic responses

recipient site : the site into which a graft or transplant material is placed

re·cip·ro·cal : the manner in which one part of a prosthesis is made to counter the effect created by another part (GPT-1)

reciprocal arm: see RECIPROCAL CLASP

reciprocal clasp : a component of the clasp assembly specifically designed to provide reciprocation by engaging a reciprocal guiding plane; it contacts the action of the clasp during removal and insertion of a partial removable dental prosthesis

reciprocal click : clicks emanating from the temporomandibular joint, one of which occurs during opening movement and the other during closing movement

re·cip·ro·ca·tion 1: the mechanism by which lateral forces generated by a retentive clasp passing over a height of contour are counterbalanced by a reciprocal clasp passing along a reciprocal guiding plane 2: a mutual exchange 3: an alternating motion—re·cip·ro·ca·tive

1re·cord 1: to register data relating to specific conditions that exist currently or previously 2: to register permanently by mechanical means, i.e., jaw relationships—see CENTRIC RELATION R., ECCENTRIC INTEROCCLUSAL R., INTEROCCLUSAL R., OCCLUDING JAW R., TERMINAL JAW RELATION R.

2re·cord 1: an official document 2: a body of known or recorded facts about someone or something

record base : an interim denture base used to support the record rim material for recording maxillomandibular records

record rim : the occlusal surfaces fabricated on a record base for the purpose of making maxillomandibular relationship records and/or arranging teeth—called also occlusion rim

reduced interarch distance : an occluding vertical dimension that results in an excessive interocclusal distance when the mandible is in rest position and in a reduced interridge distance when the teeth are in contact—called also overclosure

re·duc·tion : the correction of a fracture or dislocation; the restoration by surgical or manipulative procedures of a part to its normal anatomic location

reference plane locator : a device used to facilitate location of the horizontal reference plane on the face of a patient

re·flec·tance : the ratio of the intensity of reflected radiant flux to that of the incident flux. In popular usage, it is considered as the ratio of the intensity of reflected radiant flux to that reflected from a defined reference standard. Specular reflection is the angle of reflection equal to the angle of incidence. Surface reflection is associated with objects having optically smooth surfaces. These objects are usually termedglossy

re·flec·tion 1: the elevation and folding back of all or part of the mucosa to expose underlying structures 2: the return of light or sound waves from a surface

re·frac·tion : the deflection of light or energy waves from a straight path that occurs when passing obliquely from one medium into another in which its velocity is different

re·frac·tory : difficult to fuse or corrode; capable of enduring high temperatures

refractory cast : a cast made of a material that will withstand high temperatures without disintegrating—called also investment cast

refractory die: any die material that is capable of enduring the high temperatures that occur during firing or casting procedures. The die is an integral part of the mold; the restoration is directly cast, molded or fired onto the refractory die

refractory flask: see CASTING FLASK

refractory investment : an investment material that can withstand the high temperatures used in soldering or casting

refractory mold : a refractory cavity into which a substance is shaped or cast

refractory prosthodontic patient: a patient unable to achieve treatment expectations despite the thoroughness or frequency of the treatment provided

re·gen·er·a·tion : renewal or restoration of a body or bodily part after injury or as a normal process—see GUIDED TISSUE REGENERATION

reg·is·tra·tion l: the making of a record of the jaw relationships present, or those desired, thus allowing their transfer to an articulator to assist in proper fabrication of a dental prosthesis 2: a record made of the desired maxillomandibular relationship and used to relate casts to an articulator—see MAXILLOMANDIBULAR RELATIONSHIP RECORD

re·im·plan·ta·tion : the act of replacing a tooth in the same alveolar socket from which it had been removed, either surgically or as a result of trauma

re·lief : the reduction or elimination of undesirable pressure or force from a specific region under a denture base. The creation of space in an impression tray for impression material

relief area : that portion of the dental prosthesis that is reduced to eliminate excessive pressure

relief chamber: see RELIEF AREA

re·line : the procedures used to resurface the tissue side of a removable dental prosthesis with new base material, thus producing an accurate adaptation to the denture foundation area—comp REBASE

re·mod·el : the morphologic change in bone as an adaptive response to altered environmental demands. The bone will progressively remodel where there is a proliferation of tissue and regressive remodeling when osteoclastic resorption is evident

remount cast : a cast formed of a prosthesis for the purpose of mounting the prosthesis on an articulator

remount procedure : any method used to relate restorations to an articulator for analysis and/or to assist in development of a plan for occlusal equilibration or reshaping

remount record index : a record of maxillary structures affixed to the mandibular member of an articulator useful in facilitating subsequent transfers

removable appliance: see REMOVABLE DENTAL PROSTHESIS

removable bridge: see REMOVABLE DENTAL PROSTHESIS

removable complete denture prosthesis: a removable dental prosthesis that replaces the entire dentition and associated structures of the maxillae or mandible

removable dental prosthesis : 1: any dental prosthesis that replaces some or all teeth in a partially dentate arch (partial removable dental prostheses) or edentate arch (complete removable dental prostheses). It can be removed from the mouth and replaced at will, 2: any dental prosthesis that can be readily inserted and removed by the patient. The means of retention for such prostheses includetissue retained RDP, tooth retained RDP, implant retained RDP or tooth and implant retained RDP. Editorial Note: examples of tissue retained removable dental prostheses include complete removable dental prostheses, interim prostheses and provisional prostheses devoid of any attachment to natural teeth; tooth retained partial removable dental prostheses include interim and definitive partial removable dental prostheses retained by clasps or/and other connector devices to natural teeth or/and dental implants

removable die system: a segmented final cast system that permits accurate removal and replacement of dies of individually prepared teeth

removable partial denture prosthesis : any prosthesis that replaces some teeth in a partially dentate arch. It can be removed from the mouth and replaced at will – also called partial removable dental prosthesis

removable prosthodontics : the branch of prosthodontics concerned with the replacement of teeth and contiguous structures for edentulous or partially edentulous patients by artificial substitutes that are readily removable from the mouth

rep·li·ca 1: a reproduction or facsimile, especially by the makers, of an original 2: a copy or duplicate, i.e., a duplicate of the surface of a component of a dental implant used to process a restoration

re·po·si·tion·ing : the changing of any relative position of the mandible to the maxillae, usually altering the occlusion of the natural or artificial teeth

repositioning splint : an intraoral maxillofacial prosthesis constructed to temporarily or permanently alter the relative position of the mandible to the maxillae

residual bone : that component of maxillary or mandibular bone that remains after the teeth are lost

residual ridge : the portion of the residual bone and its soft tissue covering that remains after the removal of teeth

residual ridge crest : the most coronal portion of the residual ridge

residual ridge resorption : a term used for the diminishing quantity and quality of the residual ridge after teeth are removed

re·sil·ient : characterized or noted by resilience, as a) capable of withstanding shock without permanent deformation or rupture or b) tending to recover from or easily adjust to change syn ELASTIC—re·sil·ient·ly adv

resilient attachment : an attachment designed to give a tooth borne/soft tissue borne removable dental prosthesis sufficient mechanical flexion to withstand the variations in seating of the prosthesis due to deformations of the mucosa and underlying tissues without placing excessive stress on the abutments

res·in \re?z?i?n\ n (14c) 1: any of various solid or semisolid amorphous natural organic substances that usually are transparent or translucent and brown to yellow; usually formed in plant secretions; are soluble in organic solvents but not water; are used chiefly in varnishes, inks, plastics, and medicine; and are found in many dental impression materials 2: a broad term used to describe natural or synthetic substances that form plastic materials after polymerization. They are named according to their chemical composition, physical structure, and means for activation of polymerization—see AUTOPOLYMERIZING R., COPOLYMER R.

resin-bonded prosthesis : a fixed dental prosthesis that is luted to tooth structures, primarily enamel, which has been etched to provide mechanical retention for the resin cement. Early design incorporated perforations on the lingual plate (Rochette Bridge) through which the resin bonded material passed to achieve a mechanical lock; subsequently, use of acid etching of the metal plate (Maryland Bridge) eliminated the need for perforations.

resin-bonded splint : a fixed splint made of heavy wire, fibrous resin materials or/and cast metal that is bonded to the labial or lingual surface of natural teeth with an acid etch technique. It is used to stabilize traumatically displaced or periodontal compromised teeth

resin crown : a resin restoration that restores a clinical crown without a metal substructure

resin-modified glass ionomer: a modified glass ionomer cement that incorporates polymerizing monomer and a cross-linking agent; this type of cement has a longer working time and is less sensitive to water contamination than conventional glass ionomer cements; also called hybrid ionomer cement

resin-retained prosthesis: see RESIN-BONDED PROSTHESIS

resin-veneered restoration: a fixed restoration that uses a metal framework on which an esthetic resin veneer is applied

resistance form : the features of a tooth preparation that enhance the stability of a restoration and resist dislodgment along an axis other than the path of placement

resorption : the loss of tissue substance by physiologic or pathologic processes—see ALVEOLAR RESORPTION

rest : a projection or attachment, usually on the side of an object—see CINGULUM R., INCISAL R., LINGUAL R., OCCLUSAL R., PARTIAL DENTURE R., PRECISION R., SEMIPRECISION R.

rest area: see REST SEAT

rest bite: see PHYSIOLOGIC REST POSITION

rest jaw relation : the habitual postural jaw relation when the patient is resting comfortably in an upright position and the condyles are in a neutral, unstrained position in the glenoid fossae (GPT-4)

rest occlusion: see PHYSIOLOGIC REST POSITION

rest position: see PHYSIOLOGIC REST POSITION

rest relation: see PHYSIOLOGIC REST POSITION

rest seat : the prepared recess in a tooth or restoration created to receive the occlusal, incisal, cingulum, or lingual rest

rest vertical dimension : the distance between two selected points (one of which is on the middle of the face or nose and the other of which is on the lower face or chin) measured when the mandible is in the physiologic rest position

res·to·ra·tion : a broad term applied to any material or prosthesis that restores or replaces lost tooth structure, teeth, or oral tissues

re·tain·er : any type of device used for the stabilization or retention of a prosthesis—see DIRECT R., FIXED PARTIAL DENTURE R., INDIRECT R.

re·ten·tion : that quality inherent in the dental prosthesis acting to resist the forces of dislodgment along the path of placement— see DIRECT R., INDIRECT R.

retention arm : an extension that is part of a partial removable dental prosthesis and is used to aid in the fixation of the prosthesis; a part of a clasp

retention form : the feature of a tooth preparation that resists dislodgment of a crown in a vertical direction or along the path of placement

retention of the denture : the resistance of a denture to dislodgment (GPT-4)

retentive arm: see RETENTIVE CLASP

retentive circumferential clasp : a circumferential clasp arm that is flexible and engages the infrabulge area of the abutment tooth at the terminal end of the arm

retentive clasp 1: a clasp specifically designed to provide retention by engaging an undercut 2: a flexible segment of a partial removable dental prosthesis that engages an undercut on an abutment and that is designed to retain the prosthesis

retentive fulcrum line 1: an imaginary line connecting the retentive points of clasp arms on retaining teeth adjacent to mucosa-borne denture bases 2: an imaginary line, connecting the retentive points of clasp arms, around which the removable dental prosthesis tends to rotate when subjected to dislodging forces

retinal fovea : a small ellipse-shaped depression in the central region of the retina somewhat less than a degree of visual angle in maximum diameter and characterized by the sharpest cone vision. The fovea centralis is the normal center for visual fixation and attention

retrodiscal tissue : a mass of loose, highly vascular and highly innervated, connective tissue attached to the posterior edge of the articular disk and extending to and filling the loose folds of the posterior capsule of the temporomandibular joint—called also bilaminar zone

ret·ro·gnath·ic : a retruded position of the mandible in relation to the maxillae

retromolar pad: a mass of tissue comprised of non-keratinized mucosa located posterior to the retromolar papilla and overlying loose glandular connective tissue. This freely movable area should be differentiated from the pear-shaped pad

retromylohyoid area : that area in the alveolingual sulcus just lingual to the retromolar pad that extends down to the floor of the mouth and back to the retromylohyoid curtain. It is bounded anteriorly by the lingual tuberosity (GPT-4)

retromylohyoid space : an anatomic area in the alveololingual sulcus just lingual to the retromolar pad bounded anteriorly by the mylohyoid ridge, posteriorly by the retromylohyoid curtain, inferiorly by the floor of the alveololingual sulcus, and lingually by the anterior tonsillary pillar when the tongue is in a relaxed position

retruded contact: contact of a tooth or teeth along the retruded path of closure. Initial contact of a tooth or teeth during closure around a transverse horizontal axis

retruded contact position : that guided occlusal relationship occurring at the most retruded position of the condyles in the joint cavities. A position that may be more retruded than the centric relation position

re·tru·sion : movement toward the posterior

re·tru·sive : denotes a posterior location

reverse articulation : an occlusal relationship in which the mandibular teeth are located facial to the opposing maxillary teeth; the maxillary buccal cusps are positioned in the central fossae of the mandibular teeth

reverse articulation teeth : posterior teeth designed to accommodate the buccal cusps of the maxillary teeth positioned in the fossae of the mandibular teeth

reverse curve : a curve of occlusion defined by the cusp tips and incisal edges which, when viewed in the sagittal plane, is curved upward or in a cephalic manner—comp CURVE OF SPEE

reverse occlusal curve: see REVERSE CURVE

reverse swallow: see TONGUE THRUSTING

reversible hydrocolloid : colloidal gels in which the gelation is brought about by cooling and can be returned to the sol condition when the temperature is sufficiently increased

reversible splint : any means of stabilizing teeth that does not irreversibly alter the structure of the teeth

Richmond crown [C.M. Richmond, U.S. dentist (1835-1902)] obs 1: a dowel-retained crown made for an endodontically treated tooth using a porcelain facing 2: an artificial crown consisting of a metal base that fits the prepared abutment of the natural tooth and carries a post or pivot for insertion into the endodontically treated root canal: a porcelain facing reinforces the metal backing—called also porcelain-faced dowel crown

ridge : an elevated body part; a long, narrow, raised crest—see ALVEOLAR R., CENTER OF THE R., CREST OF THE R., RESIDUAL R.

ridge augmentation : any procedure designed to enlarge or increase the size, extent, or quality of deformed residual ridge

ridge crest : the highest continuous surface of the residual ridge not necessarily coincident with the center of the ridge

ridge lap : the surface of an artificial tooth that has been shaped to accommodate the residual ridge. The tissue surface of a ridge lap design is concave and envelops both the buccal and lingual surfaces of the residual ridge

ridge relation: see RIDGE RELATIONSHIP

ridge relationship : the positional relationship of the mandibular residual ridge to the maxillary residual ridge

ridge resorption: see RESIDUAL RIDGE RESORPTION

ridge slope : the slope of the crest of the mandibular residual ridge from the third molar region to its most anterior aspect in relation to the inferior border of the mandible as viewed in profile (GPT-4)

rigid connector : a cast, soldered, or fused union between the retainer(s) and pontic(s)

ring less investment technique: an investing technique that uses a removable paper or plastic cylindrical outer form permitting unrestricted expansion of the investment by comparison to the use of a steel casting ring

Roach clasp [Finnis Ewing (Frank) Roach, U.S. prosthodontist, educator, and inventor, (1865-1960)]: eponym—see INFRABULGE CLASP

Rochette Bridge [Alain L. Rochette, French physician and dentist]: a resin-bonded fixed dental prosthesis incorporating holes within the metal framework and lutes to the lingual aspect of teeth adjacent to an edentulous space that replaces one or more teeth —see RESIN-BONDED PROSTHESIS

Rockwell hardness number: (RHN) a hardness measurement obtained from the depth of indentation after use of either a steel ball or conical diamond point. The Rockwell hardness number is designated to the particular indenter and load employed (Rockwell C, Rockwell M, etc.)

rod: the photoreceptor in the retina that contains a light-sensitive pigment capable of initiating the process of scotopic vision, i.e., low intensity for achromatic sensations only

1roent·gen [W. C. Roentgen, German physicist (1845-1923)]: relating to x-rays

2roent·gen : the international unit of measurement of x- or gamma radiation in air—abb r or R

roentgen ray 1: the electromagnetic radiation [greater than 100eV] emitted from a highly evacuated tube, excited by the bombardment of the target anode with a stream of electrons from a heated cathode 2: electromagnetic radiation produced by the excitation of the inner orbital electron of an atom

roent·gen·o·gram : a photograph made with x-rays

roent·gen·o·graph : a shadow image record made on a sensitized film or plate by roentgen rays

roentgenographic interpretation: an opinion formed from the study of a roentgenograph (GPT-1)

root : the portion of the tooth apical to the cementoenamel junction that is normally covered by cementum and is attached to the periodontal ligament and hence to the supporting bone

root form endosteal dental implant: an endosteal dental implant shaped in the approximate form of a tooth root

root fracture : a microscopic or macroscopic cleavage of the root in any direction

rotating condyle: see WORKING SIDE CONDYLE

ro·ta·tion 1: the action or process of rotating on or as if on an axis or center 2: the movement of a rigid body in which the parts move in circular paths with their centers on a fixed line called the axis of rotation. The plane of the circle in which the body moves is perpendicular to the axis of rotation

rotation center : a point around which all other points in a body move

rotation line obs: see FULCRUM LINE

rotational path removable partial denture : a partial removable dental prosthesis that incorporates a curved, arcuate, or variable path of placement allowing one or more of the rigid components of the framework to gain access to and engage an undercut area

rouge : a compound composed of ferric oxide and binders used for imparting a high luster to a polished surface, glass, metal, or gems

RPD: acronym for Removable Partial Denture (now termed a Partial Removable Dental Prosthesis)

RPI: acronym for Rest, Proximal Plate, and I-BAR; the clasp components of one type of partial removable dental prosthesis clasp assembly

ruga ; ·gae: an anatomic fold or wrinkle—usually used in the plural sense; the irregular fibrous connective tissue ridges located in the anterior third of the hard palate

rugae area: see RUGA

rugae zone: see RUGA