Flashcards in G P E Deck (81)
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Articulator
a mechanical instrument that represents the temporomandibular joints and jaws, to which maxillary and mandibular casts may be attached to simulate some or all mandibular positions and movements.
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Occludor
a prosthetic device intended to set the upper and lower cast in a given position. It is mostly used in recording ICP. Some occludors may simulate mouth opening and closing.
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„Scribing”/”Positional” Articulators
Instruments permit eccentric motion based on engraved records obtained from the patient. For imitating the tooth guidance primarily in horizontal plane. Movements are guided by the 3 or 4 pins and cups holding the guiding material, which are developed similarly to the incisal pin and table of the articulators. In vertical dimension only the vertical and horizontal overbite determines the movements of the mandible.
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Arcon articulator
an articulator that applies the arcon design (articulator condylare); this instrument maintains anatomic guidelines by use of condylar analogs attached to the mandibular element and fossae assemblies attached to the maxillary element.
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Nonarcon articulator
an articulator whose condylar path components are part of the lower member of the articulator and whose condylar replica components are part of the upper member.
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Occlusal plane
is an imaginary plane, which rests on three characteristic points – the mesial corner of the incisal edge of the lower left central incisor (incision inferius), and the disto-buccal cusp tips of the two distal most (third or second) mandibular molars.
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Incision inferius
the mesial corner of the incisal edge of the lower left central incisor.
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Pantograph
an instrument used to graphically record the paths of mandibular movement in one or more planes, and to provide information for the programming the adjustable articulators.
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Frankfort horizontal plane
called also eye-ear plane or auriculo-orbital plane. A plane passing through the lowest point of the margin of the left orbit (orbitale) and the highest point in the margin of each external auditory meatus (porion). [It approximates to the horizontal, when the head is in a normal upright position]. It is the most important reference plane of the head; it is theoretically parallel to the horizon when the patient is in the natural head position.
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Camper’s plane
called also acanthion-external auditory meatus plane. Established by the left tragion-subnasale point-right tragion. A plane extending from the inferior border of the ala of the nose to the superior border of the tragus of the ear. After the patient has lost the teeth it can be used to determine the occlusal plane, because it is parallel with this.
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Intercuspation
The cusp-to-fossa relationship of the upper and lower posterior teeth to one another. The interlocking or fitting together of the cusps of opposing teeth. Also called interdigitation. A cusp creates occlusal contacts around the fossa or on the marginal ridge of the opposing tooth.
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Occlusal unit
each tooth makes contacts with two opposing teeth, with the exception of the lower central incisor and the upper wisdom tooth. The three occluding teeth are called an occlusal unit.
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Occlusal surface
The collective surface of the individual teeth that is intended to make contact with the occlusal surfaces of the opposing teeth. This surface is a complicated, curved surface, with a horseshoe shape. The area of the grinding surface is only a few square centimeters.
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Curve of Spee
The edges of the mandibular incisors and the cusps of the mandibular grinding teeth are situated under the chewing plane, on a concave arch. From lateral view, an imaginary line is drawn through the buccal cusp tips of the lower posterior teeth (molars and premolar) conformed to a fairly even curve in an anterior to posterior direction. This curvature is within the sagittal plane only. The occlusal surface of the lower premolars look distally, while the occlusal surface of the second and third molar looks mesially, deepest point of the Spee curve is on the place of the first lower molar.
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Curve of (Monson) Wilson
From the frontal aspect, the buccal cusps of the mandibular molars are higher than the lingual cusps. The cusps are situated in the frontal plane on a concave curve.
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Bonwill triangle
is an imaginary equilateral triangle bounded by lines connecting the contact points of the mandibular central incisor’s incisal edge (incision inferius, or the mid-line of the mandibular residual ridge) to each condyle (usually its midpoint) and from one condyle to the other. It has an importance in the construction of articulators and in the mounting of casts in the articulator.
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Balkwill angle
the angle formed between the Bonwill tirangle and the occlusal plane, it is on average 22º, and opened distally.
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Cusp
part of the occlusal surface of a posterior tooth (premolar, molar). A cusp is a hard eminence on a tooth that emerges from the occlusal surface of the tooth. The cusp is similar to a prism, with three surfaces, rounded edges and convex surfaces, like a trieder, the apex has also a rounded form, is not sharp.
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Mesial and distal cusp ridges
cylindrical slopes started from the tip of the cusp to mesial and distal direction, cusp ridges are eminences that radiate from cusp tips. There are two marginal ridges, mesial and distal. They are located on the mesial and distal borders of the occlusal surface.
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Triangular ridge
is a convex surface, lying between the tip of the cusps and the central groove of a cuspal tooth.
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Marginal ridge
cylindrical feature of the teeth which borders the occlusal surface of the premolar and molar teeth mesially and distally.
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Centric cusp
(also functional cusp) the bigger, broader and more rounded cusps, which make contacts with two cusps of the opposing teeth around the central fossa. These cusps are known as the centric, centric holding or stamp cusps. These cusps provide the vertical distance between the mandible and the maxilla. Centric cusps are the buccal cusps on the lower teeth and the palatal ones on the upper teeth.
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Non-centric cusp
(also non-functional cusps) the non-centric or shear cusps are narrower than the centric cusps. They make contact only with one cusp in the opposing dental arch, they support it. They protect the bucca and tongue during chewing by keeping away soft tissues. They are the lingual cusps in the lower arch and the buccal cusps in the upper dental arch.
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Mesial and distal fossa
is situated at the mesial and distal end of the central groove, and forms an area slightly wider than the groove near to the marginal ridges.
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Central fossa
a third fossa on the molars in the middle of their occlusal surface at the meeting point of the grooves.
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Main/central groove
runs in mesiodistal direction between the buccal and lingual cusps of the premolars and molars, also named developmental grooves, since they are formed at the sites where the cusps grow together.
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Supplemental groove
smaller grooves on the surface of the cusps, they separate the triangular ridge from the mesial and distal cusp ridges.
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Central fissure
the bottom of the groove is called sulcus or fissure, the one in the central groove is the central fissure.
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Intercuspal space
the triangular area above the groove, between the bucccal and oral cusps of a tooth.
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