Selection of Teeth PDF

Selection of artificial teeth DCSD441 Removable Prosthodontics ◼ Reference ◼Chapter 11 Rahn ◼ Objectives of the lecture ◼ Understand how to select ◼ 1-size ◼ 2- Shape ◼ 3-Shade ◼ For anterior and posterior teeth. Artificial teeth selection is artistic skill and sci...

Selection of artificial teeth DCSD441 Removable Prosthodontics ◼ Reference ◼Chapter 11 Rahn ◼ Objectives of the lecture ◼ Understand how to select ◼ 1-size ◼ 2- Shape ◼ 3-Shade ◼ For anterior and posterior teeth. Artificial teeth selection is artistic skill and scientific knowledge Harmony between the teeth ,face ,head and skin ◼ 1)Correctly interpret the esthetic desires of the patient. ◼ 2)Recognize the practicality of those desires and discuss this information with the patient in treatment planning and again throughout treatment. ◼ 3) Coordinate the patient's realistic desires with the dentist’s personal esthetic and functional philosophies in construction of the definitive prostheses.  Selection of artificial teeth ◼ I- Anterior teeth selection: ◼ II-Posterior teeth selection: 1-Pre extraction records Photographs ◼ How to calculate from photo ◼ 2-Examination of exciting denture ◼ What did he like or dislike ◼ What changes he wants ◼ I- Anterior teeth selection: ◼ A-Maxillary anterior teeth: ◼ (Size , Shape , Shade (Color) ◼ 1 - Size: ◼ a- Width: ◼ Size of the face: ◼ Width of the central incisor is related to the bizygomatic width. ◼ Caliper or a face bow may be used as a caliper to make these measurements. ◼ The width of the six anterior teeth can be estimated. This measurement can be obtained in several different ways. A conventional method is to use the relaxed corners of the mouth to indicate the middle to distal edges of the canines. Marks are made on the maxillary occlusion rim indicating this relaxed position. Getting some patients to relax may be difficult, but this is an important landmark, so effort should be made to obtain accurate marks. ◼ A second guide that can be used to estimate the canine-to-canine measurement is to measure between the centers of the left and right hamular notches (A) and add 10 mm. This is a very easy, quick, and an acceptably accurate estimate for most patients. However, it is always advisable to use multiple methods to arrive at this size estimate ◼Clinicians need to add 7 mm to the interalar measurement to produce the width of the six maxillary anterior teeth,  The cuspid eminences ◼ The approximate location of the cuspid eminence (the apex of the upper natural canine) can be determined by extending parallel lines from the lateral surfaces of the ala of the nose, corners of the mouth onto the labial surface of the upper occlusion rim. The distance between the two marks following the contour of the arch is the combined width of the six maxillary anterior teeth. Two canine eminences. ◼ Distance measured between the two canine lines. ◼ (from the distal surface of the canine to the distal surface of the other canine) ◼ Represent the width of the upper six anteriors. Trubyte tooth indicator b- Length: ◼ The incisal edges must show below the upper lip by 2-3mm. ◼ The length is affected by the available space between the two arches.  The lips: During speech, the incisal edges of maxillary anterior teeth contact the lower lip at the junction of the moist and dry surfaces of the vermilion border. This is best demonstrated when the letter F is pronounced by the patient. A direct measurement between the high lip line and occlusal plane.The addition of 1 to 3 mm may be necessary to provide meaningful measurement High lip line and low lip line ◼ 2- Shape: ◼ a. Shape of the arch: ◼ There is direct relationship between the shape of edentulous upper arch (ovoid, taper or square) and the shape of the upper incisor teeth. b. Shape of the face: ◼ Shape of the face is oriented with two lines, one on either side of the face, running 2.5cm in front of the tragus of the ear and touching the angle of the mandible. ◼ If these lines are parallel → the face is square. ◼ If they converge towards the chin→ the face is tapered. ◼ If they diverge toward the chin → the face is ovoid.  ◼ If these lines are parallel → the face is square. If they converge towards the chin→ the face is tapered.  they diverge toward the chin → the ◼ If face is ovoid. ◼ In the square form, the sides of the face roughly parallel the vertical lines. For the square tapering form, the upper face outline will parallel the lines and the lower will taper inward. The tapering form will exhibit a diagonal from the forehead to the angle of the mandible. The ovoid face shows an overall curved outline. ◼ The labial surface of the teeth should be in harmony with the facial profile. ◼ If the face presents flat profile → a tooth with flat labial surface is appropriate. ◼ If the face presents a curved profile → a tooth with curved labial surface is appropriate. ◼ c. Sex: ◼ Curved facial features are always associated with femininity. ◼ Square features are always associated with muscularity. ◼ Therefore: ◼ Teeth of females are → ovoid or tapered. ◼ Teeth for males are → square. ◼ 3-Shade (Color): ◼ Facts to be considered during selection of shade: ◼ 1. The shade of teeth on any previous dentures is often the shade of choice for patients. ◼ 2. Although teeth tend to darken over time, there is no specific shade of artificial teeth that can be used for a given age group. ◼ 3. The selection of tooth shade may be based upon the facial complexion. The least conspicuous shade is often the best choice. ◼ 4. Make use of any pre-extraction shade determination. ◼ 5. Recently extracted teeth may be useful, but caution is advised. Extracted teeth tend to lighten in shade with drying or storage in disinfectant solutions. ◼ 6. Listen to the patient’s desires. blends in with the patient’s skin tones and does not stand out as being too light or dark. The clinician should select two or three shades and then allow the patient to make the final decision The patient should view the recommended shades standing before a mirror ideally at a conversational distance. Input from the spouse or relative or someone close to the patient should be sought. No matter the clinician’s recommendation, the desires of the patient should be followed. An acceptable tooth mold and shade has now been chosen. ◼ The actual shade guide tooth should be observed in three locations: ◼ 1) outside the mouth and beside the cheek, ◼ 2) under the upper lip with just the incisal edge exposed and ◼ 3) under the upper lip with the mouth open and two-thirds to three-fourths of the tooth exposed. B-Mandibular anterior teeth: ◼ Selection of the six anterior teeth. ◼ Each set of upper anterior teeth has a corresponding set of lower anterior teeth which match it in the size, shape and shade. II-Posterior teeth selection: ◼ Selectionof posterior teeth involves shade, size, number and form: ◼ The shade of the posterior teeth should be in harmony with that of the anterior teeth. The buccolingual dimension : ◼ The posterior teeth should be less than that of natural dentition to: ◼ 1- reduce the occluding forces upon the alveolar ridge during function. ◼ 2-will favor the cheek and the tongue to keep the denture in its place. ◼ N.B. → This reduction should not be accomplished at the expense of losing cheek support. The anteroposterior dimension: ◼ The length of the edentulous area between the distal of the mandibular canine and the ascending area of the mandible ( anterior to the retromolar pad). ◼ N.B. → Placement of tooth on an ascending area could direct forces on an inclined plane which may dislodge the denture. The mold selection designated by the guide may be correct, but because of inadequate space, a premolar or molar may be omitted from the tooth arrangement.  Vertical length ◼ The length of lower posterior teeth should coincide with the center of the retromolar pad. Thank You