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ANTERIOR TOOTH SELECTION. dr shabeel pn. 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.
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ANTERIOR TOOTH SELECTION dr shabeel pn
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. • Sex • The form and contour of the face • Age
THE FORM AND CONTOUR OF THE FACE • According to Leon Willians classification face • Three types • Square • Tapering • Ovoid
SEX • Dentogenic concept : sex, personality, age , are the factors which determine the form of anterior tooth