Arrangement of Artificial Teeth

Key factors considered during tooth arrangement include: bone resorption pattern, aesthetics, occlusal plane, harmony with tooth contour, and interdigitation of teeth.

Bone Resorption Pattern

Maxilla resorbs upward and inward, becoming smaller.
Mandible resorbs outward and becomes wider.
This resorption pattern causes many edentulous patients to appear prognathic.
Upper anterior teeth should be placed labially to the crest of the ridge to reinstate the natural position of the anterior teeth.

Aesthetics

Masculine characteristics are expressed through cuboidal, muscular, and vigorous physical appearance.
Denture teeth should reflect these attributes and be positioned boldly for a masculine appearance.
Femininity is conveyed by roundness, smoothness, and softness.
Tooth shapes should express soft lines and be positioned to complement facial features.
The highest point of the upper lip during smiling is the high lip line. Cervical necks should lie at or above this line.
Shorter teeth compromise aesthetics if selected.
The distance between canine tips should match the width of the nose base.
Width of upper centrals should match the philtrum width.

Occlusal Plane

The vertical distance between ridges is a critical factor.
The selection of maxillary anterior teeth length is influenced by lip considerations.

Harmony of Teeth with Contour

The position of the residual ridge relative to its resorptive pattern influences tooth arrangement.
Tooth forms are important; square, tapering, and ovoid forms are some considerations.

Interdigitation of Teeth

The process of fitting teeth together in a harmonious manner during the arrangement of the teeth.

Setting up of Teeth

Mark mouth corners on wax occlusal rims.
Extend lines from the lateral edge of the nose to the maxillary occlusal rim.
Mark a line perpendicular to the palate midline through the distal incisive papilla border

Central Incisor

Long axis should be parallel to the facial midline.
Labial contour should blend with the facial contour.
Rotation will vary based on arch form.

Maxillary Lateral Incisor

Oriented at a 5° angle to the perpendicular.
Incisal edge is approximately 1mm short of the horizontal plane.
Labial surface is angled inward at the cervical end.
The distal half is slightly rotated lingually.

Canine

Cervical end more prominent labially.
Turning point in the arch; mesial half harmonizes with anterior teeth; distal half harmonizes with posterior teeth.
Cusp tip touches the occlusal plane.

Other Notes

Anterior teeth should generally follow the contour of the lower lip. Incorrect placement of anterior teeth will not follow the lower lip contour.
The long axis of the central incisor should be parallel to the vertical viewed from the front, and slope labially when viewed from the side. Incisal edge should be 1-2 mm above the horizontal plane.
Central incisor: long axis slightly inclines towards the vertical axis (when viewed from the front), slopes labially (when viewed from the side), and incisal edge about 2 mm above the occlusal plane.
The long axis of a lateral incisor should be parallel to the vertical axis when viewed from the front and slope labially.
Lateral incisor: long axis inclines slightly towards the vertical axis when viewed from the front, slopes labially when viewed from the side, and incisal edge approximately 2 mm above occlusal plane.
Canine: long axis leans slightly towards the midline when viewed from the front; slightly lingually when viewed from the side, and cusp slightly more than 2 mm above occlusal plane.
The mandibular central is proclined more than the lateral. The lateral is fairly upright. The canine has the most prominent neck.
Class 1 canine relationship.
Limits of placing anterior teeth are limited by phonetics and aesthetics.
First premolar: long axis parallel to vertical view from labial, palatal cusp 0.2 mm short from buccal cusp from horizontal plane.
First molar: long axis slopes buccally when viewed distally; mesiolingual cusp
Second molar: more inclined than first molar, cusps are above horizontal plane.
Mandibular 2nd molar: long axis leans more lingually (front), mesially (side); all cusps are at a higher level than 1st molar, buccal and distal cusps are higher than others. Occlusal contact: mesiobuccal cusp between upper molars.
Lingual and mesial inclination of 2nd molar long axis, cusps are at a higher level above the occlusal plane.
Buccal corridor: space between teeth and inner surface of cheeks. Excessive corridor results from posteriorly placed posterior teeth, inadequate buccal corridors result from buccally placed posterior teeth.
The lower anterior teeth
The setup for class II and class III cases.
Setting up of anterior in class III, maxillary anterior teeth set up anteriorly on crest of ridge (for aesthetics), maxillary anterior teeth set with their incisal edges inclined labially; mandibular anteriors are set up slightly lingually on the ridge, without tongue interference.
Setting up of posterior in class II: Upper posteriors inside the ridge to occlude with lowers. Never place lowers outside the ridge (instability).
Set up in class II jaw relationships: flattened lingual cusp (uppers) occlude with flattened buccal cusp (lowers). Upper molars are set with their lingual cusp in the modified central cusp of lower teeth. Posteriors have centric occlusion with stable non-deflective stops.
Set ups in class III relationships: If ridges are edge-to-edge, anterior teeth are also placed edge-to-edge. Extreme protrusion use negative or reverse horizontal overlap, interchange upper & lower teeth, eliminate 1st premolar from upper arch. Grid transverse ridges of upper posteriors.