Arrangement of Anterior Teeth Lab 3 Video

  Arrangement of Anterior Teeth

Artificial tooth arrangement for complete dentures can be difficult and time-consuming.  Consult the faculty and staff when you need help.

Anterior artificial teeth are arranged primarily for esthetics.  Even when great care is taken to select the proper mold and shade for a particular patient, an unnatural denture can still be created if care is not taken during tooth arrangement.

The general pattern of bone loss, though modified by individual variations, is essentially upwards and backwards for the maxillary anterior residual ridge and down
wards for the mandibular anterior residual ridge.  Therefore, maxillary artificial anterior teeth must be arranged anteriorly and inferiorly to the residual alveolar ridge to occupy the position formerly occupied by the natural teeth.  Remember the maxillary anterior teeth are arranged "down and out" from the ridge.

1. Maxillary anterior teeth

The criteria for arrangement of maxillary anterior teeth are as follows:

a. Maxillary central incisors

1. The long axis of the tooth should be perpendicular to the horizontal plane (occlusal plane or the mandibular occlusion rim).

2. The contact point should coincide with the midline of the face.

3. The incisal edge should touch the mandibular occlusion rim.

4. The facial surface of the central incisors should be 5-9 mm anterior to the center of the incisive papilla.

b. Maxillary lateral incisors

1. The long axis should incline slightly distally.

2. The cervical portion of the tooth should incline slightly lingually.

3. The incisal edge of the lateral should be raised approximately 1 mm from the mandibular occlusion rim.

c. Maxillary canines

1. The incisal edge of the canine should touch the mandibular occlusion rim.

2. The long axis should be perpendicular to the occlusal plane.  The cervical third of the labial portion of the canine should incline buccally to achieve some prominence.  

3. The mesiolabial aspect of the canine should be visible when viewed from the anterior.  This will be accomplished by tilting the neck of the canine slightly to the distal (in addition to being tilted to the buccal).

2. Mandibular anterior teeth

The incisal guide angle is the angle formed by a line drawn through the incisal edges of the maxillary and mandibular incisors in a horizontal plane.  In complete denture treatment this angle is determined by the person arranging the artificial teeth.  In denture fabrication the mandibular incisors should not touch the maxillary incisors in centric relation.  The incisal guide angle should be kept as low as possible to allow free movement of the teeth in eccentric jaw movements without compromising denture stability.

a. Mandibular central incisors

1. The long axis of the mandibular central incisor should be set perpendicular to the  occlusal plane.  

2. Arrange the anterior teeth.  Set the mandibular central incisors so that the maxillary incisors cover them, 1 mm vertically and 1 mm horizontally (1 mm horizontal and vertical overlap) if you are using anatomic posterior teeth.

3. The contact point of mandibular incisors should coincide with the midline of the maxillary teeth.

b. Mandibular lateral incisors

1. The long axis of the mandibular incisor should be slightly inclined distally at the cervical portion of the tooth.

2. The occlusal height should be the same at the central incisors.

c. Mandibular canines

1. The long axis of the mandibular canine is nearly perpendicular to the occlusal plane with a slight distal inclination.

2. The tip of the canine should be at the same occlusal height as the mandibular central and lateral incisors.

In some instances, such as when a large horizontal overlap (Class II) creates phonetic problems, a compromise position for the mandibular incisors may be necessary.  The limit of compromise on a mandibular denture is the labial border.  You will make the mandibular denture unstable if you arrange the mandibular incisors any further labially than the labial border.

3. Arch form

Anterior teeth are set to follow the arch form of the patient's residual ridges.  The incisal edges of the anterior teeth should be set to correspond to the shape of the arch.  A square arrangement is indicated for a square-shaped maxillary residual ridge, a tapering arrangement for a tapering ridge form, and an oviod arrangement for an oviod arch.

4. Instruments and materials

a. Bunsen burner and matches

b. Wax, baseplate (pink)

c. Hanau torch

d. Artificial teeth previously selected

e. Burs to trim acrlic/porcelain

f. Carver

h. Articulating ribbon

i. Metal occlusal template

5. Procedure 

There are many different ways to arrange anterior teeth.  This procedure is a technique to guide you in your first attempts.  Use the occlusion rim as your guide to the labial contour and height.  Complete the tooth arrangement to the best of your ability, evaluating it based on the criteria provided in this manual.  Consult the Prosthodontic faculty in your Clinic  for assistance.

a. Locate the midline on the maxillary occlusion rim.  Extend this mark onto the land area of the maxillary cast with a pencil.  Usually, this line coincides with the center of the incisive papilla.

b. Using a warmed knife, cut enough wax from the right side of the maxillary occlusion rim to allow you to position the right central incisor.

c. Arrange the upper central incisor with its mesial edge at the midline previously marked using the occlusion rim remaining on the left as a guide.  Also, use the guidelines presented in the beginning of this section.  It may be necessary to grind on the record base with a rotating instrument.  It may also be necessary to adjust the ridge lap portion of the denture tooth.

d. Seal the tooth in position on the lingual surface with wax.

e. Arrange the right lateral and canine in the same manner.

f. Now, cut away the left side of the anterior portion of the maxillary occlusion rim and arrange the left central, lateral, and canine teeth.  Evaluate the position of the incisal edges of these teeth relative to the plane of occlusion using a metal occlusion template or its substitute.

g. Repeat the preceding operation to arrange the mandibular anterior teeth.  When you will be using 0 degree posterior teeth (ex., monoplane, Rational), the incisal guide table is set at 0 degree and the anterior teeth are arranged  so there is no vertical overlap.  No other adjustment of the incisal guide table is necessary.

When using posterior teeth with cuspal inclines, set the mandibular anterior teeth so the maxillary anterior teeth have a horizontal overlap over the mandibular teeth of 1 to 1.5 mm in normal jaw relations.  The incisal guidance, and therefore the incisal guide angle, is determined by the amount of horizontal and vertical overlap of the anterior teeth established by the dentist.

h. When properly arranged, the long axis of the maxillary canine will coincide with the distal surface of the mandibular canine, when viewed from the buccal.  Alternatively, the mandibular canines can be arranged  first in the proper relationship to the maxillary canines ( the cusp tip of the mandibular canine is placed between the maxillary canine and lateral).  You then arrange the centrals and laterals in
the remaining space.