ANTERIOR TOOTH SELECTION. SIZE OF THE TEETH Selection of the size and the teeth is a problem in three dimension. First we have to consider whether to.

ANTERIOR TOOTH SELECTION

SIZE OF THE TEETH

• Selection of the size and the teeth is a problem in three dimension .

• First we have to consider whether to use porcelain or acrylic teeth.

SIZE OF THE FACE

• The average width of the maxillary central incisor is estimated to be one sixteenth of the face measured between the zygoma.

• The size of the maxillary central incisor is important for they are the most prominent teeth in arch as individual is viewed from frontal position.

• “the tribute tooth indicator” is useful in determining the maxillary central incisor.

SIZE OF THE MAXILLARY ARCH

• The mold selector can be used to make measurement of the maxillary cast.

• Accurately contoured occlusion rims are required

• The mold selector is used in the selection of anterior teeth .The measurments are made from the midline on the maxillary occlusion rim to the distal of the cuspid eminence

• Measure the distance from the distal of one cuspid eminence to the distal of the other with a flexible.

MAXILLARY MANDIBULAR RELATION

• Any disproption in size between thr maxillary and mandibular arches influence the length, width, and the position of the teeth.

• In instances of protruded mandible, the mandibular anterior teeth are frequently larger than normal. If the mandible are retruded the mandibular anterior teeth are frequently smaller.

INCISAL PAPPILAE & THE CUSPID EMINENCE OR THE

BUCCAL FRENUM• If the cuspid eminence are visible, a line can be

placed on the cast at the distal termination of the eminence.

• If the cuspid eminence are not visible the attachment of the buccal frenum can be used. A line placed slightly anterior to the frenum attachment will be distal of the eminence.

• Measure the distance from the distal of one cuspid eminence to the distal of the other with a flexible.

CONTOUR OF THE RESIDUAL RIDGE

• The artificial teeth should be placed to follow the contour of the residual ridges that existed when the natural teeth were present.

• The loss of contour as a result of resorption, accident or surgery makes this a difficult task.

THE VERTICAL DISTANCE BETWEEN THE RIDGES

• The length of the teeth is determined by the available space between the existing ridges.

• When the space is available, it is more esthetically acceptable to use a tooth long enough to eliminate the display of the denture base

THE LIP

• When the lips are relaxed and apart the labial surface of the maxillary anterior teeth support the upper lip.

• The incisal edge extends inferior to or slightly below the lip margin.

Length

• The length of the upper six anterior teeth is normally such that the neck of the teeth will overlap the anterior ridge by 2-3mm

• Cervically up the incisive edges of the centrals will show below the relaxed lip.

HARMONY

• The face length is taken from supra orbital ridge line to inferior border of the chin.

• Breadth is the distance between the zygomatic process

• The length is greater than width would indicate teeth of htose proportions, irrespective of their shape.

BERRY’S BIOMETRIC INDEX

• Used to derive the length of central incisor using zygomatic width or the length of the face.

• Width of the maxillary central incisor=zygomatic width/ 16 =length of the face/20

POUNDERS FORMULA

• To determine the length and width of central incisor using the zygomatic width and length of face respectively.

WIDTH

• Most satisfactory way of selecting teeth width

• Choose a set which are wide enough to allow the canines to be mounted on the canine eminence when set up.

GOLDEN PREPORTION

• G.P for each patient is measured as follows • The width of the central incisor was multiplied by

62% and compared with the width of central incisor is in G.P to the width of lateral incisor.

• In comparing with the width of lateral incisor multiplied by 62% with the width of adjacent canine it can be determined if the width of lateral incisor is in golden proportion to the width of canine.

PHYSIOLOGICAL

• The facial musculature contributes to esthetics of the patient

• Increasing the thickness of the denture base in the labial and the buccal sulci can produce a puffy appearance.

PSYCHOLOGICAL

• A patient with a +ve self evaluation shows a broad smile up the one width a negative self evaluation shows a tight lipped small smile

• The campers line the psychological plane of orientation

BIOMECHANICAL

• The teeth should be placed such that they fulfil the biomechanics of the denture.

• The teeth should be set in the neutral zone.

COLOUR OR SHADE

• Colour is described by means of

• hue

• Chrome

• Value

FORM OF THE ANTERIOR TEETH

• The form of the teeth should be coformed to contour of the face as considered from the labial, mesial, distal and incisal aspect

• The general outline of the tooth should conform to the general outline of the face when viewed from frontal aspect.

• Three factors are used as guides in the selection of anterior teeth for form.

1. Sex 2. The form and contour of the face 3. Age

THE FORM AND CONTOUR OF THE FACE

• According to Leon Willians classification face

• Three types

1. Square

2. Tapering

3. Ovoid

SEX

• Dentogenic concept : sex, personality, age , are the factors which determine the form of anterior tooth