DEN203 Prosthetic Dentistry II Lecture Notes PDF

DEN203 Prosthetic Dentistry II Lecturer: Dr. Rana Turunç Oğuzman & Dr. Demet Ayvalıoğlu E-posta: [email protected] SELECTION AND ARRANGEMENT OF ARTIFICIAL TEETH FOR COMPLETE DENTURE PROSTHESIS Altınbaş Üniversitesi Rana Turunç Oğuzman [email protected] DEN203 Protetik Diş...

DEN203 Prosthetic Dentistry II Lecturer: Dr. Rana Turunç Oğuzman & Dr. Demet Ayvalıoğlu E-posta: [email protected] SELECTION AND ARRANGEMENT OF ARTIFICIAL TEETH FOR COMPLETE DENTURE PROSTHESIS Altınbaş Üniversitesi Rana Turunç Oğuzman [email protected] DEN203 Protetik Diş Tedavisi 2 Tooth Selection • The selection of artificial teeth for edentulous patients requires a knowledge and understanding of a number of physical and biological factors that are directly related to the patient. Anterior tooth selection • Factors to be considered for selection of anterior teeth: A. Shade (color). B. Size. C. Form. Anterior tooth selection SHADE: • Colors have four qualities: 1. 2. 3. 4. Hue Saturation (chroma) Brilliance (value) Translucency • All these are involved in selection of teeth Anterior tooth selection HUE: • It refers to the dominant wavelengths present in a spectral distribution e.g. red, green, yellow, etc. • The hue of the teeth must be in harmony with the hue of the patient’s face. Anterior tooth selection SATURATION (Chroma): • It is the amount of color per unit of area of an object Anterior tooth selection BRILLIANCE (Value): • It refers to the lightness or darkness of an object Anterior tooth selection TRANSLUCENCY: • Depends on transmission of light through an object • Presence of translucency makes the teeth looks alive Anterior tooth selection The factors considered in tooth shade selection are: 1. Age 2. Sex 3. Complexion 4. Patient preference Age: • The younger the patient, the lighter the color is preferred. • The color of natural teeth darken with age because of deposition of secondary dentin , wearing away of enamel and external staining from oral fluids, foods or tobacco. Sex: • The sex may effect color, it seems that females rather have brighter teeth than males. Race: • The color of the face should harmonize the color of teeth. Lighter teeth are suitable for lighter skin, while darker teeth are suitable for darker skin • People with dark skin are seemed to have very light teeth. This is because of contrast in the skin and tooth color. Patient preference(Method of pair comparison): • Give the patient a mirror and hold a complete shade guide against the patient’s lip and ask them to point to the one that they prefer. SIZE • The size of the teeth should be in proportion with the size of the face and head • Women’s teeth are often smaller than men’s • A distinct difference between incisal level of central and lateral teeth is desirable in women SIZE • Following factors are used as a guide to select the size of the teeth ▪ Methods using: • pre-extraction guides • anthropological measurements of the patient • theoretical concepts • anatomical landmarks 1.Methods Using Pre-extraction Guides • Diagnostic casts, • Photographs, • Radiographs, 2.Methods Using Anthropological Measurements 1. Anthropometric cephalic index 2. Berry’s biometric index 3. H. Pound’s formula Anthropometric cephalic index (Sears) Transverse circumference of the head is measured using a measuring tape at the level of the forehead Circumference of the head – Width of the upper CI=------------------------------------------13 bi-zygomatic width – Total Width of the upper anterior =------------------------------------------3.36 4 Total Width of the lower anterior = ---- Width of the upper anteriors 5 Berry’s biometric index bi-zygomatic width Width of the upper Cl = ---------------------------16 length of the face Length of the upper CI=---------------------------20 H. Pound’s formula bi-zygomatic width Width of the upper CI= ----------------------------16 length of the face length of the upper CI=----------------------------16 Methods Using Theoretical Concept 1. 2. 3. 4. Winklers concept Typal form theory: Leon Williams (1917) Temparamental theory: Dr. Sparzheim Concept of harmony: J.W. White 1.Winklers concept • According to Winkler, the teeth should be selected based on three different perspective which are ➢Physiological ➢Psychological ➢Biomechanical 1.Winklers concept Physiolgical • Facial musculature contributes to the esthetics of a patient • Increasing the thickness of the denture base in the labial and Buccal sulci can produce a puffy appearance • Facial wrinkles fade when the vertical dimension is increased 1.Winklers concept Psychological • Camper’s line is the psychological plane of orientation • It is raised in happy people • It is tilted in depressed people 1.Winklers concept Biomechanical • According to this, teeth should be set in the neutral zone 2.Typal form theory: Leon Williams (1917) • According to this, the shape of the teeth should be inverse of the shape of the face 3.Concept of harmony: J.W. White in 1872 • According to this concept, the size and color of the teeth should be in harmony with the size of the head and color of the sclera Methods Using Anatomic Landmarks • Seven anatomic entities are used as guides to selection of anterior teeth for size: 1. Size of the face 2. Incisal papilla and the cuspid eminence or the Buccal Frenum 3. Maxillomandibular relations 4. The contour of the residual ridges 5. The vertical distance between the ridges 6. The lips 1.Size Of The Face • The average width of the maxillary central tooth is estimated to be 1/16 of the width of the face between zygoma. • The combined width of 6 maxillary anteriors is slightly less than 1/3 of bizygomatic breadth of the face. 2.Incisal Papilla And The Cuspid Eminence Or The Buccal Frenum: • The measured distance between this two cuspid eminences gives the combined width of the six maxillary teeth • The central incisors are placed 8-10 mm anteriorly from the incisal papilla The vertical line from ala of the nose should coincide with the middle of the canine and the facial midline should coincide with the midline of the central incisors 3. Maxillomandibular Relations: • The sizes and the positions of the teeth will have to vary from the accepted normal if the teeth in the one arch are to complement the teeth in the other arch. • In instances of protruded mandibles the mandibular teeth are frequently larger than normal. • If the mandibles are retruded, the mandibular teeth are frequently smaller. 4.The Contour Of The Residual Ridges: • The artificial teeth should be placed to follow the contour of the residual ridges that existed when the natural teeth were present. 5.The Vertical Distance Between The Ridges: • The length of the teeth is determined by the available space between the existing ridges. 6.The Lips • When the teeth are in occlusion and the lips are together, the labial incisal third of the maxillary anterior teeth supports the superior border of the lower lip • In speech the incisal edges of the maxillary anterior teeth contact the lower lip at the junction of the moist and dry surfaces of the vermilion border. Anterior tooth selection FORM OF ANTERIOR TEETH: 1. Shape of the patient’s face or facial form 2. Patient’s profile 3. Dentogenic concept Anterior tooth selection Shape of the patient’s face or facial form – This is based on the Typal form theory by Leon Williams – According to him, facial form can be described • square, • ovoid and • tapering. Anterior tooth selection Profile of the face: • Can be divided into three: – Straight, – Convex or – Concave. • The labial surface of upper central incisor viewed from the mesial aspect should be in harmony with profile of the face. Anterior tooth selection Dentogenic concept Dentogenics is the art, practice and technique of creating the illusion of natural teeth in artificial dentures and is based on the elementary factor influenced by sex, personality and age of the patient. Anterior tooth selection Dentogenic concept: Sex: – In female, the incisal angles are more rounded and the teeth have lesser angulation while in males, the incisal angles are rounded to a lesser degree – The incisal edge of the CI ( Central incisor) is parallel to the lips and the laterals are slightly above the occlusal plane in males. But in females it follows curve of the lower lip (CI & LI) – The distal surface of CI are rotated posteriorly in females. Anterior tooth selection Dentogenic concept: Sex: – Lateral incisors • Mesial surface is rotated anteriorly in relation to CI in females • In males, the mesial ends are hidden by the CI. This makes the canine very prominent – Canines • Only the mesial thirds are visible in females because they are rotated anteriorly in relation to the CI whereas even the middle two-thirds of the canine are visible in males Anterior tooth selection Dentogenic concept: Age: – Age can be easily separated into young, middle or elderly. – Due to decrese in muscle tone, sagging of the cheeks and the lower lips occur. To prevent cheek biting, horizontal overlap of the posterior teeth can be increased. – Inter-occlusal distance reduces with age. Hence, mandibular teeth are more visible than the maxillary teeth. – In old patients the teeth tend to have square form due to attrition, more round features disappear and line-angle is quite seen in those patients. Anterior tooth selection Dentogenic concept: Age: – Old patient have gingival recession, & can be immitated on the dentures – The color of the teeth also changes with age. Personality: – It seems reasonable that a large vigorous type of people have teeth of size and form with prominent markings, different from those of a delicate appearing patient. MATERIALS OF ANTERIOR TEETH: There are two main types: 1. Porcelain, 2. Acrylic • ACRYLIC TEETH : • PORCELAIN TEETH : ➢Not brittle, but poor abrasion resistance. ➢Esthetic very good. ➢Chemical bonding with denture base. ➢Can be easily grounded and polished ➢Transmit fewer forces to the mucosa ➢No clicking on contact. ➢Thermal expansion same as acrylic denture base. ➢Brittle, more resistant to abrasion ➢Excellent (does not stain). ➢Mechanical bonding by pins or undercuts holes. ➢Difficult to grind and polish ➢More forces to the mucosa and the alveolar ridge, accelerating bone resorption ➢Clicking on contact. ➢Thermal expansion much lower than acrylic causes stresses in acrylic denture base. Anterior tooth arrangement video • https://www.youtube.com/watch?v=DSYqeNauCDc&t=35s