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Selection of artificial teeth


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Clinical Removable Prosthodontics
Forth Year

Selection of artificial teeth

  1. 1. King Faisal University ,College of Dentistry Department of substitutive Dental Sciences, Clinical Removable Prosthodontics-I
  2. 2. Selection of Artificial Teeth for Edentulous patients
  3. 3. Lecture Outline Introduction -
  4. 4. INTRODUCTION Aesthetics is one of the objectives of the .complete denture prosthodontics Harmony between the teeth, face, head and .skin Artificial teeth selection is artistic skill and .scientific knowledge
  5. 5. .Cont No rules of thumb for teeth selection, utilizing the anatomic land marks and . manufactured aid will be helpful For the ease, we divided selection of :artificial teeth into Anterior teeth and .Posterior teeth -
  6. 6. Selection of the .Anterior Teeth
  7. 7. Selection of the Anterior Teeth : Pre-extraction guides. 1 .A. Study Casts . B. Photographs .C. Radiographs .D. Extracted Teeth
  8. 8. Pre-extraction Guides :A. Study Casts Most reliable guide in selecting the size, shape, and position of the natural .teeth
  9. 9. .Cont :B. Photographs Most recent photographs, close-up .with patient smiling Facial photographs is usually helpful for determining the anterior teeth placement, arch form, and lip support than the actual size or the mould of .artificial teeth
  10. 10. .Cont :C. Intra-Oral Radiographs Keeping in mind the radiographs distortion, radiographs will give clue about width, length and shape of the .teeth to be replaced
  11. 11. .Cont :D. Extracted Teeth Give clue about the size, shape and mould of the artificial teeth but not the .color
  12. 12. Selection of the Anterior Teeth Examination of Existing Dentures. 2 Asking patients in the initial interview :with the patient What he/she likes or dislikes?about his/her appearance ?What changes would he/she wants-
  13. 13. Selection of the Anterior Teeth Indirect Methods of teeth selection .3 (.(post-extraction guides When all the records of form, color and size are lost, it is challenging .procedure
  14. 14. Selection of the Anterior Teeth A. Size of Anterior Teeth B. Form of Anterior Teeth C. Shade of Anterior Teeth
  15. 15. Size of Anterior Teeth .Width of Anterior Teeth.1 . Length of Anterior Teeth. 2 Thickness of Anterior Teeth. 3
  16. 16. Size of Anterior Teeth .A.Width of Anterior Teeth Bizygomatic Width Using Trubyte Tooth Indicator, Face bow and ruler can be used to measure bizygomatic . width Width of the six Anterior Teeth = Bizygomatic Width/3.3 Width of the Maxillary Central Incisor = .Bizygomatic Width /16
  17. 17. .Cont . The buccolingual centres of the hamular notches Width of the six anterior teeth = distance between the buccolingual centres of the hamular notches + 5 . mm :The size and contour of the Residual Ridges :Maxillary Arch Resorption In anterior segment of the arch is in a Vertical and Palatal direction, posteriorly, the resorption is in a .Vertical and Medial direction
  18. 18. .Cont Mandubular Arch Resorption In anterior segment of the arch is in a Vertical and Lingual direction, posteriorly, the resorption is in a . vertical and slightly lingual direction Maxillary arch appears smaller and mandibular arch .larger :Corners of the Mouth The distal surface of many natural upper canines ispositioned at the corner of the relaxed mouth, which .represent inter canine distance
  19. 19. .Cont :Canine Eminence  If well-defined, the distance between lines drawn on the master cast of the upper jaw at the distal aspect . of the eminence may give inter canine distance :The width of the Nose Vertical parallel lines extending from the lateral surfaces of the ala of the nose onto the labial surface of properly contoured upper occlusal rim will give indication of the position of the cusp tips of . the maxillary canine teeth
  20. 20. .Cont Width of Upper Anterior six teeth = width of . the nose + 6 mm : Lateral Surface of the Nose Imaginary line along the lateral surface of - the nose, through the centre of the brow-line, and contacting the lateral aspect of the ala. The line on properly contoured occlusal rim gives an indication of the distal aspect of the canine at the point where the projected line .passes through the occlusal plan
  21. 21. .Cont :The Incisive Papillae The line parallel to the coronal plane contacts the natural canine teeth near the tips of the .cusps :Maxillomandibular Relations Any disproportion in size between the maxillary and mandibular arches influences the length, the width, and position of the .teeth
  22. 22. .Cont : Cranial Circumference Direct relation between the width of the six maxillary anterior teeth and cranial circumference (as horizontal circumference of the cranium about a plane passing through the glabella and maximum occipital . point Width of Maxillary anterior teeth = Crinial circumference/10
  23. 23. Length of Anterior Teeth The Vertical Distance between the :Ridges The length of the teeth is determined by the. available space between alveolar ridges It is more aesthetically acceptable to use along tooth to eliminate the display of the .denture base
  24. 24. .Cont The Lips The labial surface of the maxillary anterior teeth support the upper lip and the amount of the central incisors visible below the lipis about 2-3 mm in young people and less than half that . amount in elderly people That extension will vary in relation to .the fullness of the lips
  25. 25. .Cont When the teeth are in occlusion and the lipsare together, the labial incisal third of the maxillary anterior teeth support the superior .border of the lower lip The amount of tooth which an individual:shows varies depending on the following .Length of the upper lip .Mobility of the upper lip .Vertical dimension of occlusion (.Vertical overlap (over bite
  26. 26. .Cont Thickness of the Anterior Teeth .It has important role on phonetics In general thicker teeth have preference in .selection Ease with setting (spacing, rotation,…( and.better aesthetics The manufacturers of denture teeth usuallyrelate the size of the mandibular anterior .teeth to the maxillary anterior teeth
  27. 27. HELPFUL GUIDES IN THE SELECTION OF TOOTH SIZE Generally, larger people have larger teeth; in addition, men usually have larger teeth than women, particularly when comparing the maxillary .lateral incisors Approximate location of the distal surface of the maxillary canines can be indicated by marks made on the maxillary occlusion rim at the corners of the mouth. Then the distance between the marks is measured around the labial surface of the occlusion rim (overall width of the maxillary six (artificial teeth in curve
  28. 28. .Cont The width of most natural maxillary central incisors is over 8.5 mm and any tooth less than 8 mm is rare. The combined width of the maxillary six anterior teeth is normally 46 mm or more and .anything less than 45 mm is very unusual Natural anterior teeth vary greatly in size, but as a rule they are much larger than is generally realized and one of the commonest prosthetic errors is to use teeth which are too small, thus making them .appear obviously false
  29. 29. Form (shape( of Anterior Teeth The outline form of the anterior teeth should harmonize with the shape of the patient’s . face The shape of the maxillary central incisor bears a definite relationship to the shape of .the face They classified the human face into three basic types: square, tapering, and ovoid, may have combination of two or more of these .basic forms
  30. 30. .Cont :THE SQUARE TYPE the sides of the face are almost parallel :THE SQUARE TAPERING is similar to the square type except that the parallelism exist only on a point just below the zygomatic arches and then the face .develops a tapering effect
  31. 31. .Cont :THE TAPERING TYPE in these faces the dimensions decrease downward, the forehead being the widest, the zygomatic width somewhat less and the mandibular width .the least :THE OVOID TYPE this type is always characterized by the zygomatic width being the widest, the forehead and the .mandibular areas being of decreased dimensions the method of tooth selection become known as the .geometric theory
  32. 32. HELPFUL GUIDES IN THE SELECTION OF TOOTH FORM The Form and Contour of the Face The form of artificial anterior teeth should harmonize with the shape of the patients .face The geometric outline of the face when viewed from the frontal, mesial, distal .and incisal aspects
  33. 33. .Cont The geometric figures, square, tapering, ovoid and combinations therefore serve as a starting point in selecting the tooth form as it is viewed .from the frontal aspect The Trubyte Tooth Indicator* may be used in one :of the two ways to establish the facial outline .The general outline of the face from the frontal aspect To determine the facial profile
  34. 34. Shape of the Edentulous Maxillary Arch It was recognized that there was some relationships between the shape of the edentulous maxillary arch and the .maxillary teeth
  35. 35. .Cont Sex Curved facial features are associated with femininity and square features are .associated with masculinity Ovoid tooth is more feminine and square tooth is more masculine A curve labial surface is more feminine and the flat labial surface is more .masculine
  36. 36. .Cont Age As the features change with the aging process so does the form of the teeth. The lips lose their curves and cuspid's bow, and the teeth wear at the incisal .edges and inetrproximal surfaces The labial surface seem flatter, and the outline from appears more square
  37. 37. .Cont The male become more square in form to complement the added weight and squareness of the body, as the body of the female loses its curves, the teeth loses .their curves Age and sex should be reflected in the .tooth mould selection
  38. 38. .Cont The mould guide groups the various denture tooth moulds available into facial outline from such a square, ovoid, tapering, tapering ovoid, and square .tapering The dentist should select the anterior denture teeth from the group that coordinates with the arch form and the .patients typal face form
  39. 39.  - Mould chart provides illustration of each of the six anterior teeth and gives the measurements of the denture teeth to the right of each mould. These measurements include the length and width of the maxillary central incisor as well as the width of the six anterior teeth on curve.
  40. 40. .Cont Once you have selected the maxillary anterior denture teeth, use the mould guide chart to find the corresponding mandibular anterior denture teeth. When selecting denture teeth for Class II anterior tooth relationship, you must use a mandibular mould smaller than that recommended by the mould guide. Because of the .retruded and narrow mandibular arch from Likewise when selecting anterior denture for a Class III relationships you must use a mandibular mould larger than that recommended by the mould guide, because of the protruded and wider .mandibular arch form
  41. 41. SHADE OF ANTERIOR TEETH The selection of a suitable shade for an edentulous person is a matter of individual .judgment Color is not critical for the edentulous patient provided that it is compatible with the general coloring of the skin and to lesser extent the hair and the iris of the eyes but most importantly with the age of .the patient The hue and saturation of color in the .teeth must harmonize with that of the skin
  42. 42. SUGGESTED GENERAL GUIDELINES FOR SHADE SELECTION People with fair complexions generally have teeth with less color, and the colours are less saturated, thus the teeth are lighter and are in harmony with the color of the .face Younger patients will be exhibit a great vitality and brilliance and require lighter shade. The teeth of younger patient also often have pink tint due to underlying pulpal tissues, besides, they exhibit incisal .translucency
  43. 43. Older patients tend towards less brilliance and darker shades, brown and yellow .shades are more prevalent Maxillary central incisor are the lightest teeth in the mouth; maxillary laterals and mandibular incisors are slightly darker; .canines are darker still Breaking up the color of the anterior teeth can be accomplished by selecting teeth of different shades from different sets of six .anterior teeth
  44. 44. The apparent shade of the tooth is affected by its position of the arch. More prominent teeth appear lighter while those in a .recessed position appear darker Generally when selecting the mandibular anterior tooth shade, the same shade selected for the maxillary anterior teeth .may be used Posterior teeth are usually uniform in color .and very slightly lighter than canines
  45. 45. HELPFUL CLINICAL GUIDES IN THE PROCESS OF SHADE SELECTION Patient should be in an upright position. The dentist should be in a position so that the teeth are viewed in a plane perpendicular to the plane vision. Distance and angulation are factors of major significance. The shade selection should be evaluated from the distance as well as at close range. The teeth should also be viewed from both sides as well as from the straight frontal .position The patients mouth should not be opened too wide, but should remain a dark cavity as in .ordinary conditions
  46. 46. It is best if the dentist eliminates all but two or three shades before conferring with the patient. He should never approach the .patient with entire shade guide Hold the shade guide outside the mouth against the skin of the face, and also near the eyes of the hair of the patient. Harmony should exist between the color of the teeth .and the color of the skin, hair and eyes Always moisten the shade guide with saliva or water
  47. 47. Always place the teeth under consideration in the shade of the upper lip in the position they are too occupy; they will appear darker .in this position than in the hand Attempt to look at the face as a whole rather than focus entirely on the teeth, and whenever possible select the teeth shade under natural or color – corrected artificial .light
  48. 48. Eyes fatigue to color perception very rapidly. Looking steadily at a soft blue, gray green card before looking at the shade guide of the tooth as beings placed in the appropriate area of the patient mouth. Another method is to place different shade guide in rapid succession in and out of the mouth and go by the first impression of which is best match. The squint test may be helpful. Many practitioners prefers the flash .perception technique
  49. 49. When in doubt about a particular shade select a tooth which is obviously too dark, and view it in position then try one which is obviously too light, gradually merging these two extremes .until pleasing shade selection Remember that the lighter the shade .the more artificial the tooth looks
  50. 50. Patient participation in shade selection .can be very delicate matter Remember that the apparent shade of a tooth is affected by its position in the arch; more prominent teeth appear lighter while those in a recessed .position appear darker
  51. 51. TOOTH ARRANGEMENTS It remains the dentists responsibility to select the mould, shade and material and .ultimately to refine the arrangement Arrangement of the anterior teeth should be individualized to the patients cosmetic needs the bottom line is that the teeth must look like they belong in the patients .mouth The time devoted to arranging the anterior teeth is often greater than for any other .steps in denture fabrication
  52. 52. Arranging the anterior teeth while the patient is present can be worthwhile for .both the patient and dentist
  53. 53. DENTOGENIC CONCEPT IN SELECTING ARTIFICIAL TEETH Frush and Fisher introduced the dentogenic concept for establishing the .esthetics of a patient’s complete denture Also tended to use darker shades in men or patient with bold and vigorous .personalities They used lighter shades in women and .patients with delicate personalities They also advise the dentist to select arrange and alter teeth an carve the gingiva to suit the patient age and sex and .personality
  54. 54. Age Natural teeth wear with age in most patients and this wear can be simulated by grinding the .incisal edges, of the denture teeth Chips or notches can also be placed on the incisal .edges The labial surfaces of the anterior teeth can be .roughened to remove surface gloss With increasing age, the amount lips are gently parted decreased from 2-3 mm at age 29 to no .teeth showing at 60 years of age
  55. 55. Incisor with approximately 05 mm showing at age 29 and 2-3 mm showing the age of .60 In youth the interdental papillae are pointed closely, adapted to the tooth. And stippled. With age, they become shortened blunted, edentulous and smooth, with signs of gingival recession around the .necks of some teeth
  56. 56. Sex For anterior tooth arrangement appear feminine, the incisal edges must follow a .curve which suggests softness An anterior mesial rotation of the lateral incisor combined with a slightly cervical inclination of one of the central incisors and a canine with its cervical portion facing outward compared to the incisal edge, .provides a feminine arrangement
  57. 57. A more masculine appearance is achieved by a more square tooth form. The incisal edges are flat with less of a curve to the edges of .the six anterior teeth The central incisor can be arranged so that the incisal edges are in line with each other, or even and level at the mesial edges to .create an even more masculine arrangement
  58. 58. Personality Attempting to position and shape the teeth to complement the patients personality . involves getting to know the patient Although the guidelines of dentogenics are not absolute they do offer helpful suggestions for enhancing the cosmetic .appearance of many patients teeth
  60. 60. :considered in relation to Shade. 1 Size and number. 2 Form. 3 Material. 4
  61. 61. SHADE OF POSTERIOR TEETH The shade of the posterior teeth should harmonize with the shade of the anterior teeth. The maxillary premolars are sometimes used more for esthetics than . for functional purposes They may be slightly lighter than the other posterior teeth but not lighter than the .anterior teeth
  62. 62. SIZE AND NUMBER OF POSTERIOR TEETH Space available for posterior teeth may be :defined in three dimensions Buccolingual dimension Mesiodistal dimension Occluso-gingival dimension - :BUCCOLINGUAL DIMENSION it is considered to have the buccolingual width of the artificial teeth less than that of .natural teeth Should not be accomplished at the .expense of losing support for the checks
  63. 63. .Cont MESIODISTAL DIMENSION Overall mesiodistal width of the posterior teeth is determined by the length and .slope of the mandibular residual ridge The mesiodistal width of the posterior teeth is measured from the approximate position of the distal surface of the mandibular canine to the mesial end of the .retromolar pad The total mesiodistal width in millimeters of the posterior teeth is often used as a .mould number
  64. 64. .Cont OCCLUOGINGIVAL DIMENSION Length of the posterior teeth is determined by the amount of interarch distance. The greater the distance the longer tooth which can be used in the vertical space available more aesthetically pleasing than short .tooth Most manufacturers supply posterior teeth in L (long) M (medium) and S (short) lengths
  65. 65. .Cont A few artificial tooth manufacturers produce short bite teeth for patients with minimal interarch space short bite teeth have long facial surface but short .oclusal portions
  66. 66. FORM OF POSTERIOR TEETH The three basic tooth moulds anatomic, :semianatomic and nonanatomic :Anatomic Teeth An anatomic tooth is one that is designed to stimulate the natural tooth form. The standard anatomic tooth has inclines of approximately 33 or more and somewhat .resembles natural teeth Anatomic teeth allow balance occlusion to be more readily obtained because of the cusp .length
  67. 67. .Cont If opposing ridge relations are fairly normal and the ridge size considered good, .anatomic teeth are usually indicated :Advantages Maximize estheticsProvide balanced occlusion with greater easeProvide better initial penetration of the bolus-
  68. 68. .Cont :Semi-anatomic Teeth When the cusp incline is less steep than the conventional anatomic teeth of 33 it can be classified as a modified or semianatomic teeth. These teeth still look somewhat like natural teeth but have modified features to eliminate the . problems of the purely anatomic teeth Teeth which look like well-worn natural teeth, but provide the function of .mechanical of flat plane posteriors
  69. 69. .Cont :Non-anatomic Teeth  These teeth are essentially flat (0-ddegree or cuspless) i.e. has no cusp height to interdigitate (intercuspate) with opposing .teeth :Indications Patients with crossbite tooth relationshipsPatients with poor neuromuscular control orcoordination Patients with severly resorbed ridgesPatients who have a large discrepancybetween centric jaw and centric occlusion
  70. 70. SELECTION OF THE POSTERIOR TOOTH MOULD There is no simple method of posterior teethmould selection, nor are there scientific data available to support the selection of one mould over another. Masticatory efficiency, comfort, and preservation of the supporting structures are primary concerns of both the patient and the dentist. The occlusal scheme chosen, the specific posterior tooth mould selected, and the arrangement of the teeth .are also influenced by patient factors
  71. 71. .Cont It should be understood that the concept of balanced occlusion is desired when using cusp or modified cusp form teeth and that non-balanced occlusion in the eccentric position is .desired for non-anatomic teeth
  72. 72. .Cont Factors for consideration when choosing :prosthetic teeth Ridge morphologyInterarch distanceArch relationshipNeuromuscular controlEstheticsCombination of foodPrevious denture-wearing experience- 
  73. 73. .Cont The dentist select the posterior tooth mould :after , Establishing the plane of occlusionRegistering and transferring the centric jawrelation at the proper occlusal vertical . dimension .Mounting the master casts on the articulatorSetting the horizontal condylar guidance from,the protrusive record Arranging the maxillary anterior teeth for lipsupport, aesthetic, phonetics, and Arranging the mandibular anterior teeth to.control the condylar guidance
  74. 74. .Cont :Materials of the posterior teeth Artificial posterior teeth are supplied in acrylic resin, in a combination of acrylic and metal and porcelain (airfired or vacuum-fired porcelain). Most modern porcelain teeth are vacuum.fired
  75. 75. .Cont Consideration in choosing acrylic or porcelain :include Esthetics Color stability Wear Transmission of stress Modification Polishing Bonding Fracture Repair -
  76. 76. ?ANY QUESTION
  77. 77. THANK YOU