Key terms Flashcards
Angle’s Classification of Occlusion
class 1 - 3
Class I
the ideal relationship of posterior teeth when the mesiobuccal cusp of the maxillary first molar is centered on the buccal groove of the mandibular first molar.
Class II
malocclusion in which the mandibular dental arch is posterior to the maxillary dental arch in one or both lateral segments; mandibular first molar is distal to the maxillary first molar compared to the ideal class I relationship.
Class III
malocclusion in which the mandibular dental arch is anterior to the maxillary dental arch in one or both lateral segments; mandibular first molar is mesial to the maxillary first molar compared to the ideal class I relationship.
Anterior Guidance
the influence of the contacting surfaces of anterior teeth on tooth-limiting mandibular movements.
Anterior Protected Articulation
(anterior guidance, cuspid guidance, cuspid rise) -
a form of mutually-protected articulation in which the vertical and horizontal overlap of the anterior teeth disengage the posterior teeth in all mandibular excursive movements.
Arch Alignment
(tooth alignment) - the relative position of teeth to form a curved or “U”- shaped configuration when viewed from the occlusal aspect.
Axial Inclination
the orientation of the long axis of a crown (natural or artificial) relative to the sagittal and frontal planes. It may be given generally, in terms of buccal or lingual, and mesial or distal; or specifically in degrees (some portion of 360°).
Bennett Angle
the angle formed between the sagittal plane and the average path of the non- working condyle, as viewed in the transverse plane, during lateral movements.
Balanced Articulation - (balanced occlusion)
the bilateral, simultaneous anterior and posterior occlusal contact of teeth in centric and eccentric positions. This occlusion is characteristic of heavily worn natural teeth and complete denture design.
Border Movement
mandibular movement at the limits dictated by anatomic structures, as viewed in a given plane.
Canine Protected Articulation
(canine guidance, cuspid guidance, cuspid rise)
a form of mutually-protected articulation in which the vertical and horizontal overlap of the canine teeth disengage the posterior teeth in the excursive movements of the mandible.
Centric Cusps
(supporting cusps, functional cusps, stamp cusps) -
the lingual cusps of the maxillary posterior teeth and the buccal cusps of the mandibular posterior teeth. (Assumes proper interarch alignment.) Those cusps or incisal edges of teeth that contact in and support centric occlusion, usually facial cusps of the mandibular posterior teeth, the maxillary palatal cusps, and the incisal edges of the mandibular anterior teeth.
Centric Occlusion (CO)
the occlusion of opposing teeth when the mandible is in centric relation. This may or may not coincide with the maximal intercuspation postion (see Maximal Intercuspation).
Important Note: CO used to be synonymous with maximal intercuspal position (MI), but this is now improper according to the prosthodontic glossary. Other disciplines and other dental institutions may still consider it synonymous with MI. You must be aware of this significant discrepancy in terminology when taking the Dental National Board Exams. Its intended meaning will require clarification.
Centric Relation (CR)
- the maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the shapes of the articular eminences.This position is independent of tooth contact. This position is clinically discernible when the mandible is directed superiorly and anteriorly. It is restricted to a purely rotary movement about the transverse horizontal axis. ( GPT – 8 )
- a clinically determined position of the mandible placing both condyles into their anterior uppermost postion. This can be determined in patients without pain or derangement in the TMJ (Ramsfjord).
Condylar Path -
the path traveled by the mandibular condyle in the temporomandibular joint during any movements of the mandible.
Condylar Guidance
the mechanical form located on the upper-posterior region of an articulator that controls movement of its mobile member. (This movement is intended to simulate that produced by the condyles in the temporomandibular joints.)
Curve, Anteroposterior - (curve of Spee) -
the concave (superiorly) line formed by the cusp tip of the mandibular canine and the buccal cusps of the mandibular posterior teeth (usually shown projected onto the median plane).
Curve, Mediolateral - (curve of Wilson)
viewed from the frontal plane, it is the concave (superiorly) curve which contacts the buccal and lingual cusps of the mandibular molars bilaterally.
Cusp-Fossa Contact -
the relationship that exists when a centric cusp occludes with an opposing fossa, resulting in three points of contact, with no contact on the cusp tip. Occurs in both cusp-marginal ridge and cusp-fossa occlusal schemes.
Cusp-Fossa Occlusal Scheme
( tooth-to-tooth occlusion) -
the entire arrangement of posterior teeth in which centric cusps occlude exclusively in specified fossae of the opposing maxillary or mandibular counterpart crown. This articulation is usually associated with gnathologic-based oral rehabilitation (see therapeutic occlusion).
Cusp-Marginal Ridge Occlusal Scheme
(tooth-to-two tooth occlusion) -
the entire arrangement of posterior teeth in which centric cusps occlude in specified fossae or on adjacent marginal ridges of the opposing maxillary or mandibular crown or crowns. This is the most common type of naturally occurring occlusion.
Cusp-Marginal Ridge Contact
the relationship when a centric cusp occludes with opposing adjacent marginal ridges resulting in two contact areas. Occurs in the cusp-marginal ridge scheme of occlusion but not in the cusp-fossa scheme.
Deflective Occlusal Contact
(occlusal prematurity, occlusal interference, occlusal disharmony) -
any surface which diverts the mandible from its intended movement.
Determinants of Mandibular Movement
(determinants of occlusion) -
those anatomic structures that dictate or limit the movements of the mandible when the teeth are in contact. The anterior determinant of mandibular movement is the dental articulation. The posterior determinants of mandibular movement are the temporomandibular articulations and their associated structures.
Embrasure
the spaces formed about the proximal contact areas of adjacent teeth. The embrasures may be divided into four regions: Occlusal (incisal), mesial, distal, and gingival (cervical).
Excursive Movement
movement occurring when the mandible moves away from maximal intercuspation. - excursion