CHARACTERIZATIONin prosthodontics dentistry

characterization

1. CHARACTERIZATION OF ANTERIOR TEETH Dr. Samia Shafiq Postgraduate Resident ( FCPS II ) Department of Prosthodontics FMH College of Medicine and Dentistry, Lahore. 19 th March, 2015. 1

2. Contents Definitions Characterization of Complete Dentures Characterization of Fixed Prosthesis Conclusion 2

3. Characterization 1. Characterization is defined as to alter, by application of unique markings, indentations, coloration and similar custom means of delineation on a tooth or dental prosthesis, thus enhancing natural appearance Glossary of Prosthodontic Terms- 2005 3

4. Contd … 2. Denture characterization is the modification of form and color of the denture base and teeth to produce a more lifelike appearance Rajeev Srivastava, V. C. (2011). Characterization of Complete Denture. International Journal of Dental Clinics, 3 (1), 56-59. 4

5. Characterization of Complete Dentures Characterization of Artificial Teeth Characterization of Denture Bases 5

6. Methods Complete denture can be characterized by two basic methods: Characterization of artificial teeth by: Selection Arrangement Surface modification Characterization of the denture bases by: Carving Tinting Rajeev Srivastava, V. C. (2011). Characterization of Complete Denture. International Journal o f Dental Clinics, 3 (1), 56-59. 6

7. 1. Characterization of Artificial Teeth Selection Arrangement Surface modifications 7

8. Guidelines Fisher stated the following factors influencing the tooth selection, arrangement, and characterization to enhance the natural appearance of the individual: Age Gender Personality Frush JP, Fisher RD. How dentogenic restorations interpret the sex factor. The Journal of Prosthetic Dentistry1956;6(2):160-72. 8

9. Age The central incisors express the age Age-related changes can be incorporated in the dentures by introducing the following imperfections: Crazed or fractured tooth Attrition Gingival recession Abrasion   Erosion G Rajtilak . S Deepa , V. R. (2012). Anterior Teeth and Smile Designing: A Prospective view. International Journal of Prosthetic and Restorative Dentistry, 2 (3), 117-127 . 9

10. Gender The lateral incisors express the gender characteristics A delicate mold is feminine and a vigorous mold is masculine A medium mold can be made masculine or feminine by squaring or rounding the incisal edges, respectively G Rajtilak . S Deepa , V. R. (2012). Anterior Teeth and Smile Designing: A Prospective view. International Journal of Prosthetic and Restorative Dentistry, 2 (3), 117-127. 10

11. Personality The canine teeth express the personality Aggressive, hostile personality requires a pointed, long cuspal form Passive, soft personality can be facilitated with a blunt, rounded and short cuspal form G Rajtilak . S Deepa , V. R. (2012). Anterior Teeth and Smile Designing: A Prospective view. International Journal of Prosthetic and Restorative Dentistry, 2 (3), 117-127. 11

12. i . Selection of Artificial Teeth Selecting a long tooth, and contouring the wax to show gingival recession, followed by staining it a bit, can give natural appearance by reproducing age-related gum recession Long clinical crowns with receded gingiva after periodontal destruction, may also play a role in achieving a natural-looking denture for selected patients Ku YC, Shen YF. Simple method for making a metal crown for a complete denture. Journal of Prosthetic Dentistry 2001;86(2):214-5. 12

13. ii. Arrangement of Artificial Teeth Arrangement of artificial teeth imparts its role in characterization of anterior teeth by: Varying the direction of the long axis of teeth 13

14. Placing the teeth so that the tips of the maxillary lateral incisors show when the patient speaks routinely 14

15. Using an eccentric midline 15

16. Placing one maxillary central and lateral incisor parallel to the midline, and rotating the other central and lateral incisors slightly in a posterior direction Creating asymmetry for the maxillary right and left cuspids by rotating one in a posterior direction than the other 16

17. Creating asymmetry in the divergences of the proximal surfaces of the teeth from the contact points 17

18. Placing the neck of one maxillary central incisor in a posterior direction and the neck of other central incisor in an anterior direction Placing one maxillary central incisor slightly in an anterior direction to the other central incisor 18

19. Lombardi RE. The principles of visual perception and their clinical application to denture esthetics. The Journal of Prosthetic Dentistry 1973; 29 (4):358-82. Creating slight diastema between the lateral incisor and the cuspid on one side Simulating the tooth wear and migration by positioning the artificial teeth to create spaces, can give a natural appearance 19

20. Slight modifications in the position of teeth such as overlapping, tilting, rotation and incisal variations may contribute to a natural-looking denture Esposito SJ. Esthetics for denture patients. The Journal of Prosthetic Dentistry1980;44(6):608-15. 20

21. iii. Surface modifications of Artificial Teeth A discolored tooth (as Root Canal T reated) can be shown by selecting one or two teeth of darker shade compared to the rest of the teeth set Esposito SJ. Esthetics for denture patients. The Journal of Prosthetic Dentistry1980;44(6):608-15. 21

22. Discoloration, resulting from fillings and food stains can be incorporated as required for a natural appearance 22

23. Grinding and reshaping the incisal edges and mesiodistal diameter makes it possible to modify any tooth to the desired form A hair line crack can be given in the teeth 23

24. Gold or alloy restorations can be placed on the teeth to create the illusion of naturalness The use of gold occlusal surfaces on the teeth of prosthesis can contribute to its clinical success Levin EI. Dental esthetics and the golden proportion. The Journal of Prosthetic Dentistry 1978; 40(3):244-52. 24

25. Ku YC, Shen YF. Simple method for making a metal crown for a complete denture. Journal of Prosthetic Dentistry 2001;86(2):214-5. Cast crown can be given on posterior teeth Silver filling can be given on posterior teeth 25

26. Stock artificial teeth as provided by manufacturers have a uniformity of color and shade, inherent to their production that does not impart a natural esthetic result to dentures 26

27. 27 Methods have been developed for making acrylic resin teeth by incorporating staining and characterization to natural denture teeth Tillman EJ. Molding and staining acrylic resin anterior teeth. The Journal of Prosthetic Dentistry 1955; 5(4):497-507.

28. 2. Characterization of Denture Bases Carving the Denture Bases Tinting the Denture Bases 28

29. Characterized Denture Base A denture base with coloring that simulates the color and shading of natural oral tissues Glossary of Prosthodontic Terms- 2005 29

30. Indications For Characterization of Denture Bases The indications for characterization of denture base are: Patients with an active upper lip Patients with a prominent pre-maxillary process Actors , singers and others who may expose gum tissue areas during their performances The psychological acceptance of the dentures by the patient 30

31. Methods The two commonly employed methods are: Carving the denture bases Tinting the denture bases 31

32. I. Carving the Denture Bases Festooning Stippling Carving the Alveolar Eminence Carving the Inflammed or Bulbous Gingiva 32

33. Festooning 33 A carving in the base material of a denture that simulates the contours of the natural gingival tissues Mosby's Medical Dictionary , 8th edition. © 2009, Elsevier.

34. Stippling Numerous small depressions in the surface of healthy gum tissue, producing an appearance that varies from that of smooth velvet to  that of an orange peel Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier . 34

35. Procedure 1 Wax the anterior flange and perform gingival characterization (festooning ) Flame the wax and press a synthetic sponge made from low-density polyurethane foam over the flamed region Emboss the roughness of the sponge onto the softened wax 35

36. Gently flame the anterior flange again to reduce the roughness, the gingival stippling becomes self-evident Invest and process the prosthesis, polish with pumice and finish with rag wheel and polishing compound Rajeev Srivastava, V. C. (2011). Characterization of Complete Denture. International Journal of Dental Clinics, 3 (1), 56-59. 36

37. Procedure 2 The area of the attached gingiva can be stippled at the try-in stage A modified bristle brush or toothbrush having two or three tufts at the end can be used for this purpose A series of shallow holes are produced by jabbing the surface of the wax in the selected region 37

38. The wax surface is then slightly flamed to reduce the depth of the holes and produce a dimpled effect Finally , the surface polished lightly with water and cotton wool Nayar S, Craik NW. Achieving predictable gingival stippling in labial flanges of gingival veneers and complete dentures. The Journal of Prosthetic Dentistry2007;97(2):118. 38

39. Carving the Alveolar Eminence The labial flange of a complete denture should not be a smooth curved sheet of acrylic, but instead should show a series of swellings corresponding to the alveolar eminencies over the roots of the teeth These are most marked anteriorly and become progressively less marked in the pre-molar and molar region 39

40. 40 In the upper anterior region, the canine eminence is most marked. The lateral incisor eminence is small In the lower jaw, again the canine eminence is most marked and a series of smaller ridges mark the presence of the incisor roots

41. Carving the Inflammed or Bulbous Gingiva The reflection of inflamed or bulbous gingiva can also be reproduced by leaving more interdental wax. Rajeev Srivastava, V. C. (2011). Characterization of Complete Denture. International Journal of Dental Clinics, 3 (1), 56-59. 41

42. II. Tinting the Denture Bases Background Methods Requirements of Denture Base Tinting Materials Techniques for Tinting the Denture Bases 42

43. Background Pound in 1951, incorporated the racial and individual colour peculiarities of the gingiva in artificial denture He was the first to suggest a method of tinting acrylic denture bases to simulate the gingival colour Kemnitzer , used a combination of blue and brown stains to reproduce the melanotic pigmentation of the gingiva Tillman EJ. Molding and staining acrylic resin anterior teeth. The Journal of Prosthetic Dentistry 1955; 5(4):497-507. 43

44. Methods Two methods have usually been employed to tint denture base resins to achieve a more natural appearance: Use of heat curing or auto-polymerizing resins of various shades or colors to be painted on the denture base or B. Applied to the mold during denture construction to obtain a tinted denture 44

45. Most widely applied tints today are the various pigments, which are placed within the original mold chamber, so they do not affect contour The Kayon Dental Stains or tinting resins are most widely used tints One Kayon Kit contains 5 shades Rajeev Srivastava , V. C. (2011). Characterization of Complete Denture. International Journal of Dental Clinics, 3 (1), 56-59. 45

46. Requirements of Denture Base Tinting Materials Should be readily miscible with methyl methacrylate resin Should be non-toxic Should not add appreciable bulk to denture bases Should be stable and non-fading Should be resistant to loss from abrasion in cleaning and normal function Should not alter the properties of the denture base resins Becker CM, Smith DE, Nicholls JI. The comparison of denture-base processing techniques. Part II. Dimensional changes due to processing . The Journal of Prosthetic Dentistry 1977; 37(4):450-9. 46

47. Techniques for Tinting the Denture Bases There are two techniques to be used for tinting the denture bases: Technique 1 Technique 2 Rajeev Srivastava, V. C. (2011). Characterization of Complete Denture. International Journal of Dental Clinics, 3 (1), 56-59 . 47

48. Technique 1 This technique suggests initially trial packing the denture After the trial closure, the flask is opened The tints are applied either With a small camel's hairbrush wetted with monomer Or By dusting and wetting with dropper on the external contours of the denture base and the imprints of the ridge-lap portions of the teeth With either approach only small amount of the tinted resins are added which will not cause overfilling of the mold 48

49. Advantage : This technique allows to preview the efforts for tinting to some degree 49

50. Disadvantages: The teeth are in other half of the flask, so the complementary effect of their shade cannot be appreciated Possibility of scuffing the color veneer, when it is returned to the flask Pigments are only on the surface, so subtle shading is more difficult The esthetically critical areas of gingival cuff and papilla are the most difficult once to control 50

51. Technique 2 Known as Dusting and Wetting Technique This technique has more widespread acceptance Involves applying the tints in reverse order from outside in, i.e. After dewaxing the different shades of resins are applied in different areas by dusting and wetting, prior to filling the base with the mold resins 51

52. Place as minimal an amount of monomer as necessary to barely wet the powder Allow it to stand for about 15 seconds before turning the flask The intense colors should be restricted to the deeper veneers Allow the completed veneer to stand for 10-15 minutes before packing the rest of mold. 52

53. John L. Powers, suggested that Dusting and Wetting Technique is all-imaginary in the absence of the patient and its time consuming Therefore , he developed a technique to apply the tinting material directly to the finished denture after processing, in the presence of the patient He documented that coloring of the denture varies from one patient to another, and coloring of the denture base can be modified according the tissue color of each patient Tillman EJ. Molding and staining acrylic resin anterior teeth. The Journal of Prosthetic Dentistry 1955; 5(4):497-507. 53

54. Melanin pigmented dentures mimicking the patient’s natural oral tissues 54

55. Simulating Melanin Pigmentation This method involves the use of brown and purple resins for those with pigmented oral tissues 55

56. Characterization of Fixed Prosthesis Glazing Polishing Exterinsic Colo u r Modification Composite Build-ups 56

57. Glazing Glazing is to cover with a glossy, smooth surface or coating for the attainment of a smooth and reflective surface The final firing of porcelain in which the surface is vitrified and a high gloss is imparted to the material Glossary of Prosthodontic Terms- 2005 57

58. Excessively glazed anterior teeth look unnatural A dry crown looks misleadingly underglazed Underglazing and refiring a restoration is better than overglazing it 58

59. If a restoration is not sufficiently glazed, it will retain more plaque and may be more liable to fracture After glazing, the metal surfaces of the restoration are polished Evaluation, Characterization and Glazing. (2006). In L. F. Rosentiel , Contemporary Fixed Prosthodontics (4 ed., pp. 901-905). Elsevier M. 59

60. Factors Affecting the Glazing The degree of glaze depends on the following factors: Furnace temperature Time for which the restoration is held at that particu lar temperature 60 Evaluation, Characterization and Glazing. (2006). In L. F. Rosentiel , Contemporary Fixed Prosthodontics (4 ed., pp. 901-905). Elsevier M.

61. Polishing Polishing is to make a surface smooth and glossy, usually by friction The act or process of making a denture or casting smooth and glossy Glossary of Prosthodontic Terms- 2005 61

62. An alternative to glazing is to polish the porcelain surfaces of the restoration This provides greater control of the surface luster and distribution than glazing A higher gloss on the cervical area and a lower gloss on the incisal area is possible This is not possible with glazing because the entire crown is subjected to the same time-temperature combination Hubbard JR: Natural texture and lustre in ceramics . In Preston JD, ed : Perspectives in Dental Ceramics. Chicago, Quintessence Publishing, 1988 . 62

63. Polishing Tools A number of commercial polishing kits are available Most are capable of producing smooth porcelain surfaces, if used correctly (i.e., Without omitting the successively finer grits) 63 Fuzzi M, et al: Scanning electron microscopy and profilometer evaluation of glazed and polished dental porcelain . Int J Prosthodont 9:452, 1996.

64. The use of finishing wheels followed by pumice is satisfactory as an alternative to the finishing tool kits Newitter DA, et al: An evaluation of adjustment and post-adjustment finishing techniques on the surface of porcelain-bonded-to-metal crowns. J Prosthet Dent 48:388, 1982. 64

65. Laboratory studies have shown that polished porcelain is no more abrasive than glazed porcelain Unpolished porcelain is much more abrasive on opposing enamel and is more plaque retentive than is polished or glazed porcelain Al- Hiyasat AS, et al: The abrasive effect of glazed, unglazed, and polished porcelain on the wear of human enamel, and the influence of carbonated soft drinks on the rate of wear. Int J Prosthodont 10:269, 1997. 65

66. External Color Modification A restoration that does not blend well with the adjacent teeth can be improved by simple chair-side color modification or characterization procedures These are done concurrently with final glazing, and it is therefore recommended that restorations be tried in the patient’s mouth, contoured, but unglazed 66 Abadie FR: Porcelain surface characterization and staining in the office. J Prosthet Dent 51:181, 1984.

67. A number of stain kits are available from porcelain manufacturers , and most contain a fairly wide range of colors The stains themselves are highly pigmented surface colorants that contain a small amount of glass, allowing the color to fuse into the porcelain surface 67

68. Procedure Mix the stain with the liquid provided in the kit (normally a glycerin-water mixture) to a creamy, stiff consistency Thoroughly clean the restoration with steam, before applying the stain Apply stain to the restorations with the clean moist sable brush 68

69. When the effect has been created, make a note of which stain was used and where. Place a unit in the mouth and removing the restoration without smudging Take the restorations out of the mouth, wash them, and re-create the characterization 69

70. Transfer the restorations to a firing tray, and place it in front of the muffle of the furnace until the stain is dry and the surface appears chalky white Remove the prosthesis, and examine it to ensure that no stain has run inside 70

71. Remove any excess with a dry brush, and place the crown in the furnace Increase the heat to the maturation temperature of the porcelain, and hold it there according to the degree of glaze required Remove the restorations, allow them to cool, and retry them in the patient’s mouth 71 Evaluation, Characterization and Glazing. (2006). In L. F. Rosentiel , Contemporary Fixed Prosthodontics (4 ed., pp. 901-905). Elsevier M .

72. Methods of Extrinsic Colour Modification Three aspects of characterization may be used singly, or in combination to achieve a natural appearance : Shade modification Specific characterization Special illusions of form or position Evaluation , Characterization and Glazing. (2006). In L. F. Rosentiel , Contemporary Fixed Prosthodontics (4 ed., pp. 901-905). Elsevier M. 72

73. 1. Shade Modification Shade modifications can be done by: Increasing the chroma (Saturation ) Changing the hue (shade) Adjusting the value (Brightness) 73

74. i . Increasing the Chroma Increasing the chroma (saturation) is one of the simplest shade alterations to achieve The addition of yellow stain increases the chroma of a basically yellow shade Adding orange has the same effect on a yellow-red shade 74 Lund TW, et al: Spectrophotometric study of the relationship between body porcelain color and applied metallic oxide pigments. J Prosthet Dent 53:790 , 1985.

75. A metal-ceramic restoration that has too high a chroma is difficult to modify Choosing a shade with a lower chroma is always better, because a lower chroma can be altered easily 75

76. Using the complementary color of a restoration reduces its chroma : Yellow requires purple-blue Orange requires blue or blue-green Addition of these stains lowers the value of the restoration and increases the metameric effect 76

77. ii. Changing the hue An alteration in hue is observed as: Pink-purple moves yellow toward yellow-red Yellow decreases the red content of a yellow-red shade These are the only two modifications that should be necessary, because the hue of a natural tooth always lies in the yellow-red to yellow range 77

78. iii. Adjusting the value Value can be reduced by adding a complementary color Violet is used on yellow restorations and has the added effect of increasing the translucency Gray is not encouraged because it tends to reduce translucency and makes the surface cloudy 78

79. Attempts to increase the value are generally less successful, although value can be increased if the dominant color added has a higher lightness ranking A crown can be stained with white , but opacity will be greatly increased 79

80. 2. Specific Characterization Defects should be reproduced to a slightly lesser extent on the restoration than as they appear on the natural teeth Characterization looks slightly more natural and is more permanent if applied intrinsically during the buildup of the restoration rather than by subsequent extrinsic application Winings JR: A method of making decalcifications in the porcelain build up. J Dent Technol 15:13, 1998 . 80

81. Following modifications are commonly introduced to achieve natural appearance: Hypocalcified areas Proximal coloration Enamel cracks Stained crack line Exposed incisal dentin Incisal halo Translucency Evaluation, Characterization and Glazing. (2006). In L. F. Rosentiel , Contemporary Fixed Prosthodontics (4 ed., pp. 901-905). Elsevier M. 81

82. a. Hypocalcified Areas These are produced with white stain and may be some of the easiest and most commonly made modifications 82

83. b. Proximal Coloration Helps to create the illusion of depth and separation Enables the operator to tone down excessive opacity at the cervical area The stains used are brown and orange They are applied lightly to the proximal area and extended slightly onto the buccal surface apical to the contact 83

84. c. Enamel Cracks Better if done intrinsically, although it can be added extrinsically A linear vertical crack interrupts the light transmission across the tooth surface, causing a shadow The highlight is developed with white and yellow mixed in the ratio of 4:1 , and gray stain is used for the shadow 84

85. A thin line is drawn with a brush in the desired area with the white and yellow stains Then a thin line of gray is placed distal to the first line to create the illusion of a shadow 85

86. d. Stained Crack Line An orange-brown mixture applied in as thin a line as possible will effectively simulate a crack 86

87. e. Exposed Incisal Dentin This is usually seen on the mandibular incisors of older patients and is caused by enamel wear The incisal edge should be “ cupped out ,” with orange and brown colorants used to reproduce the dentino -enamel junction 87

88. f. Incisal Halo Translucent incisal edges are more common on the incisors of younger patients This may be difficult to reproduce intrinsically A mixture of white and yellow stains in the ratio of 4 : 1 is placed in the linguo-incisal area, with an extension just onto the labial area, to produce the halo effect 88

89. g . Translucency Translucency can be mimicked with violet stain Both the labial and lingual surfaces should be coated for optimal results Decreasing the translucency is accomplished by adding the dominant hue over the labio -lingual surface 89

90. 3. Special Illusions A pontic may be very long because of loss of supporting bone Simulating a root surface can improve the appearance The root extension is contoured for length and width, and then an orange-brown mixture is placed over the extension Pink stain can be used to simulate gingival tissue , but results are better with pink body porcelain 90

91. Limitations Surface characterization causes a loss of fluorescence It increases the effect of Metamerism ( shade mismatch is more apparent under some lighting conditions). It cannot be used to make major corrections or compensate for gross errors A characterized crown is slightly rougher than an autoglazed one The stain will eventually wear away under normal toothbrushing (10 to 12 years). 91 Cook PA, et al: The effect of superficial colorant and glaze on the surface texture of vacuum-fired porcelain . J Prosthet Dent 51:476, 1984.

92. 92 Tinting and Painting

93. 93 Composite Build-ups

94. Conclusion 94

95. Characterization is a procedure in which the character or collective qualities of a person are introduced in the complete denture, either by modification of teeth or denture bases, to make it appear more natural for that particular person The esthetic aim is the production of anatomic characterization present before the extraction of teeth Every prosthesis should be characterized according to the particular patient 95

96. Thank you.. 96