Classification of patients

1.Patients with remaining natural teeth

2. Patients who have old denture

3.Patients without remaining natural

teeth and without old dentureteeth and without old denture

Objectives:

1. Esthetics

2. Masticatory function

3. Correction of speech defects

4. Preservation of the remaining tissue and muscle tonetone

- Primary selection of the teeth must be carried out at the first appointment.

Guides for the anterior teeth selection

1. Pre-extraction guides

a. Study cast

b. Photographsb. Photographs

c. Radiographs

d.Extracted teeth

2.Post extraction guides

- Selection of size (width and length)a. Size of the face and headb. Size of the contour of the maxillary archc. Maxillomandibular relations

i. In class I – Normal relationship, the teeth in one arch are compatible with the

teeth in the other arch.teeth in the other arch.ii. In class II – The mandible is retruded and the mandibular teeth are frequently smalleriii. In class III – The mandibular teeth are frequently larger than normal

- Width of the anterior teeth

a. Bizygomatic width – The average width of themaxillary central incisor is estimated to be 1-16 ofthe bizygomatic width that is, the distance betweenthe cheek bones measured just in front of the ears.the cheek bones measured just in front of the ears.

b. The width of the nose – An estimation of theposition of the apex of the upper natural canine canbe found by extending parallel lines from the lateralsurface of the ala of the nose onto the labial surfaceof the upper occlusion rim.

c. Corners of the mouth – The distance measuredbetween the two commisures (angles of themouth ) will represent the width of the upper sixanteriors from the distal surface of the canine tothe distal surface of the other canine.the distal surface of the other canine.

d.Canine eminence

e. Cranial circumference

f. Incisine papilla – It has been found that a transverse line bisecting the incisive papilla will pass through the middle of the upper canines. The necks of the upper anterior teeth overlap the anterior ridge by 1-2 mm cervically, and the incisive edges of the centrals must show below the relaxed lip by 1-2 mm in a young person and less than half that amount in an elderly patient.an elderly patient.

4. The length width ration of the patient’s face.

Length of faceLength of faceWidth of face

=Length of toothWidth of tooth

Selection of the form

- Guides for selecting the form of anterior teeth.

- Shape of the arch.

Tooth form in relation to arch form- Shape of the face

Selection of shade- Color and shade of toothThe shade consist of:a. Hue i.e specific colora. Hue i.e specific colorb. Saturation [chroma] i.e. amount of color per unit

area.c. Translucency [value] i.e ability of color to

permit light to pas through it.

Patients age – With age, darker, while lighter teeth are suitable for young patients.

Patients complexion—light teeth for fair skin, blue eyes, dark teeth usually for dark skin and black eyes.

The following facts are true for nearly all natural teeth:

a. The neck of the tooth has a more pronounced color than the incisive edge.

b.The incisive edge if not worn, is more transluscent that the body of the tooth and is usually of a bluish shade (composed entirely of usually of a bluish shade (composed entirely of enamel)

c. The upper central incisors are lightest teeth inthe mouth followed by the laterals and canines.Posterior teeth are usually uniform in color.

d.Teeth darken slightly with age.- Aid for selecting the shadeShade guides – The shade guide tooth should be

moistened and selection made in the normallight.light.

a. Outside the mouth along the side of the nose.b.Under the lip with the incisal edge exposedc. Under the lip with only the cervical end covered

and the mouth open.

The color should be matched with the skin of thecheeks.

General consideration for selection of anteriorteeth

1. Sexa. Females – All teeth are more curved, rounded

line and point angles, the teeth more ovoid ortapeing than square.tapeing than square.

b.Male – The teeth are larger with sharp line andpoint angles, the teeth more square than ovoidor tapeing.

2. Age3. Personality

Posterior teeth selection – Posterior teeth shouldhave a small bucco-lingual width to keep forceson the supporting structure to a minimum.

The mesiodistal measurements of the upperposterior teeth is taken from the distal surface ofposterior teeth is taken from the distal surface ofthe canine to the prominence of the tuberosity.The total mesiodistal width of the four posteriorteeth is often used as a mould number. Thelower posterior teeth should not extendposterior to the mesial border of the retromolarpad.

It is advisable to select upper posterior teeth aslong as possible so that the premolars will beesthically in harmony with the canine. Actuallythere are long, medium and short posteriorthere are long, medium and short posteriorteeth.

Anatomic teeth- Balanced occlusion- Young healthy patients- Good ridges

Non anatomic form or monoplane teeth- Flat occlusal surfaces (without cusp)- Not function efficiently- Not function efficiently- Balanced occlusion- Less destructive force to the tissues- Old patients having poor ridges with poor

neuromuscular control.

Advantages of anatomic teeth.1. Esthetically acceptable

2. More efficient in cutting of food, thereby reducing forces that are directed to the supporting structures during masticatory movement.

3. They can be arranged in balances occlusion

Disadvantages of anatomic teeth.

1. It is mandatory to use an adjustable articulator.2. Eccentric records must be done for articulator

adjustments3. Clinical remount is essential to adjust the

occlusion after denture settling.occlusion after denture settling.4. Balanced occlusion lost when settling occurs.5. More horizontal forces during functions.6. Frequent relining, Fast bone resorption

Advantages of non anatomic teeth1. Comfortable

2. The allow greater range of movements which isnecessary in patients with mal-related jaws (as thosewith Para functional jaw habits or wide mandibularmovement)

3. Non anatomic teeth exerts less horizontal or torquingforces, so they are used with flat ridge cases.

4. Centric record only is needed4. Centric record only is needed

5. When the neuromuscular control are souncoordinated, the jaw records are not repeatable

Disadvantages of non anatomic teeth.

1. They are of unnatural look

2. Less cutting efficiency

3. The flat teeth occlude in two dimensions only,but the mandible has 3 dimension movements.but the mandible has 3 dimension movements.

Porcelain teeth- Wear is clinically insignificant over a long period of

time- No significant loss vertical dimension- Allow for the total rebasing procedures- Maintain communicating efficiency- Difficult to grind and fit into a close inter-ridge

spacespace- Cause dangerous abrasion to opposing gold crown

and natural teeth.- Have a sharp impact sound- Will not bond to the base material except with

mechanical means. The anterior porcelain teethhave pins at the back, while the posteriors haveholes.

Acrylic resin teeth.

- Wear is clinically significant

- Loss of occlusal vertical dimension due to wear.

- Occlusal surface is altered by wear.

- Do not chip, and have softer impact sounds

- Easy to adjust and polish

- Easy to grind into close inter ridge space

- Will bond to base material by chemical union.

- Minimal wear to opposing natural teeth andgold crowns. This is a definite indication for theiruse

Acrylic teeth are used in the following situations

1. Limited inter-arch distance

2. Maxillary single denture against natural dentition.

3. Maxillary single denture opposing partial denture

4. Opposing natural teeth with gold occlusalsurfaces

Upper and lower posterior teeth can be- Both porcelain- Both acrylic- A combination of porcelain and acrylic resin teeth

on opposing dentures can be used. It softens the impact sounds, reduces friction and eliminates chipping.

- Upper posterior porcelain anatomic teeth with non anatomic lower resin teeth

- Upper posterior porcelain anatomic teeth with non anatomic lower resin teeth

- Upper and lower posterior acrylic teeth with upper anterior porcelain teeth is contraindicated because the resin teeth will wear rapidly resulting in occlusal destruction of the underlying tissues.