1. OF ARTIFICIAL TEETH FOR COMPLETELY
SELECTION
OF ARTIFICIAL TEETH FOR COMPLETELY
EDENTULOUS PATIENTS
Prof.Dr. Ahlam El-Sharkawy
Head of prosthodontic departement
Pharos University in Alexandria

2. Introduction
The anterior teeth are primarily selected to satisfy the esthetic requirement , where as the posterior teeth are primarily selected to satisfy the functional requirements .
The anterior teeth are composed of six maxillary and six mandibular teeth.

3. OBJECTIVES FOR TOOTH SELECTION
TO CONSTRUCT THE COMPLETE DENTURE THAT…………
1. FUNCTION WELL EFFICIENT
FOR MASTICATION.
2. ALLOW PATIENT TO SPEAK NORMALLY.
3. ESTHETICALLY PLEASING.
4. PRESERVE TISSUE STRUCTURES OF THE GNATHODYNAMIC SYSTEM
5. SHOULD MAINTAIN THE VERTICAL DIMENSION

4. Selection of anterior teeth

5. Anterior teeth selection
Guides for the anterior teeth selection
Pre-extraction guides
Study cast
Photographs
Radiographs
Extracted teeth
Old denture.

6. If the pre-extraction records are not available systematic procedure can be followed to select the teeth which will harmonize with the patient’s facial characteristics

7. Maxillary anterior teeth Selection
Size
Shape (Form)
Shade (color).

8. Selection of size
Width
Length.

9. Width of the anterior teeth

10. a. Bizygomatic distance
The average width of the maxillary central incisor is estimated to be 1:16 of the bizygomatic width
Bizygomatic width the distance between the cheek bones measured just in front of the ears.

11. a. Bizygomatic distance
The combined width of the six maxillary anteriors is about one third the bizygomatic width.

12. b. The width of the nose
An estimation of the position of cusp tip of the upper natural canine can be found by extending parallel lines from the lateral surface of the ala of the nose onto the labial surface of the upper occlusion rim.

14. c. Corners of the mouth
The distance measured between the two commisures (angles of the mouth ) will represent the width of the upper six anteriors from the distal surface of the canine to the distal surface of the other canine.

15. Corners of the Mouth Mark corners at rest (#7 wax spatula)
Position of distal of the canines

16. Length
The necks of the upper anterior teeth overlap the anterior ridge by 2-3 mm cervically, and the incisive edges of the centrals must show below the relaxed lip by 2-3 mm in a young person and less than half that amount in an elderly patient.

17. Amount of tooth shown About 2 mm of teeth are shown when lip is relaxed.

18. High Lip Line Highest point of upper lip when smiling
Cervical necks lie at or above this line
If shorter teeth are selected, esthetics compromised

19. Guidelines for Setting Anterior Teeth
High Lip Line
Corner of Mouth
Angulation is as important as midline

20. FORM OF THE ANTERIOR TEETH.
The guides for selecting the form of anterior teeth :
1- Shape of the face.
2- Shape of the arch.

21. 1-The shape of the face .
According to Leon Williams classification the human face has been classified into
Three types
Square
Tapering
Ovoid

22. SQUARE , OVOID , TAPERING FORMS

23. The shape of the maxillary central incisor coincides with the inverted form of the face

24. Selection of the form Shape of the face.
It was claimed that the shape of the upper central incisor bears a definite relationship to the shape of the face.
Thus if one of these teeth is enlarged and the incisal edge placed above the brows with the neck of the tooth on the chin, then the outline of the tooth would nearly coincide with that of the face.

25. SQUARE
Facial form
- the width of the forehead, zygomatic arch and mandibular angle is equal.
Profile
- straight and flat ala area
Incisal form
- mesial and distal lines are almost parallel till the length of 2/3rd from incisal edge.

27. ovoid
Facial form
- width of zygomatic arch is wider than the distance of forehead.
Profile
- ovoid ala area
Incisal form
- mesial and distal lines are curved.

28. Tapering
Facial form
- the width becomes narrow from forehead towards the zygomatic arch and mandibular angle.
Profile
- curved or flat
Incisal form
- mesial and distal lines become narrow from incisal edge to cervical end.

29. Selection of the form
2-Shape of the arch.

30. Patient’s sex and age: A cuboidal tooth form is required for the males
A spheroidal form for the females.
Teeth for males should have a less convexity than for females.
The incisal edge of older patient is flat to resemble attrition of natural teeth.

31. Dentogenic concept (SPA)
Sex, personality, age are the factors which will determine the form of the anterior teeth

32. Personality
The dentist should select and arrange teeth so that it improves the patient’s personality. The patient can be vigorous ore delicat.
More squarish and large teeth are selected for vigorous people

33. Feminine MUSCULINE Prominent teeth Smaller teeth Large sized teeth
Square arch form
Square labial surface
Square incisal edges and corners
Darker shade
Flat smiling line
Canine – cervical area is more visible and prominent
Feminine
Smaller teeth
Round corners
Curved contours & arch form
Curved labial surface
Round incisal edges and corners
Delicate appearance
Curved smiling line
Canine – mesial 3rd only seen

34. Age Younger people Older people Lighter shade
More incisal translucency
Minimal wear of incisal edge
Curved smiling line
Pointed canines
Older people
Darker shade
Less incisal translucency
increased wear of incisal edges
Flat smiling line
Loss of tips of canine

35. Check Shade Against the Patients Face
Check shade of existing denture
Ask if patient wants same shade or change
Allow patient to view shade against lip with mirror
Obtain patient approval

36. 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.

37. The anterior teeth from the lightest to the darkest
Upper central incisor
The upper lateral
The lower central and lateral
The upper and lower canines are the darker.

38. II-Selection of posterior teeth

39. 1-Size of posterior denture teeth
a-Length:
This is determined by the amount of denture space available between the upper and lower ridges.

40. b-Width
From distal of canine to the tuberosity in the maxillary denture, and to the retromolar periphery of the lower denture.
The teeth with a narrower buccolingual width than the natural teeth are selected.

41. Posterior Tooth Selection
Buccolingual size can affect the tongue space
smaller teeth if tongue space is limited

42. Posterior teeth selection
Posterior teeth should have a small bucco-lingual width to keep forces on the supporting structure to a minimum. The mesiodistal measurements of the upper posterior teeth is taken from the distal surface of the canine to the prominence of the tuberosity. The lower posterior teeth should not extend posterior to the mesial border of the retromolar pad.

43. 2-Form of the occlusal surface (Mould or shape)
Cusp angle :the angle made by the slope of the cusp with the cusp plane

44. Cusp Height : The perpendicular distance between the tip of the cusp and its base plane

45. Anatomic Teeth (10°, 20°, 30°, 40°)
10°
20°
30°

46. Cusped Teeth (Anatomic teeth) have cusp angle Indicated when there is a well defined ridge and normal jaw relations.

47. 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

48. Disadvantages of anatomic teeth
1. It is mandatory to use an adjustable articulator. 2. Eccentric records must be done for articulator adjustments 3. Clinical remount is essential to adjust the occlusion after denture settling. 4. Balanced occlusion lost when settling occurs. 5. More horizontal forces during functions. 6. Frequent relining, Fast bone resorption

49. Flat or Inverted Cusped Teeth Have zero cusp angle with grooves to aid mastication

50. Non-Anatomic Teeth (0°, Rational, Monoline, etc.)
Jaw size discrepancies (Class III)
Severe ridge resorption
Poorer esthetics, due to lack of cuspal inclines

51. Indications of flat plane teeth
1-In class II and III jaw relations.
2- patients with temporomandibular joint disorders.
3-In case of atrophic alveolar ridge.
4-In the presence of hyper mobile gingival tissues (flabby ridge).

52. Disadvantages of flat plane teeth
a) Reduced masticatory efficiency.
b) Poor appearance.
c) Food may become packed into the depression of teeth.
d) It is very difficult to obtain balance. .

53. 3-shade (color) The same shade as the canines should normally be used
one or two shades darker.

54. Tooth material
Artificial teeth for complete denture are either acrylic teeth or porcelain teeth

55. Denture Tooth Material
Porcelain teeth less common now
Acrylic easier to set and adjust

56. Comparison between acrylic and porcelain teeth
1-Hardness and abrasion resistance:
Porcelain teeth are harder and more resistant to wear.

57. 2-Aesthetics
the appearance of porcelain teeth had a better reputation than the acrylic teeth.
The porcelain teeth will not have stains, while acrylic teeth can be stained

58. 3-Retenion to denture base
The bonding of porcelain teeth to the denture base is purely mechanical. This by pins on anterior teeth and holes in posteriors
Retention of acrylic teeth to denture base is chemical.

59. 4-Thermal expansion
The coefficient of thermal expansion of porcelain is much lower than acrylic resin which my results in cracking of acrylic base.
The coefficient thermal expansion of acrylic teeth is the same as acrylic denture base.

60. 5-Adjustment
Porcelain is more difficult to grind and difficult to polish
Acrylic can be ground and easily polished.

61. 6-Density
Acrylic teeth are lighter in weight

62. 7-Impact strength
The impact strength of acrylic teeth is greater than that of porcelain.
So acrylics may be used in cases of close anterior occlusion.

63. 8-In service Acrylic teeth transmit less force to the mucosa.
On contact with the opposing teeth, acrylic teeth are less noisy. While With Porcelain teeth, clicking occurs on contact with the opposing teeth.

64. 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 occlusal surfaces

65. Denture Tooth Material
Acrylic
New acrylics wear better
Improved translucency with layers
More resilient - Less breakage
Chemically bonds to base
Quieter
Easier to set/adjust
Gum sticks
Porcelain
Less wear
More translucent
Brittle - fracture easily
Don’t bond to base (stain, fall out)
Difficult to set, adjust

66. Porcelain teeth
- Wear is clinically insignificant over a long period of time - No significant loss vertical dimension - Difficult to grind and fit into a close inter-ridge space - 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 teeth have pins at the back, while the posteriors have holes.

67. 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 and gold crowns. This is a definite indication for their use

68. The following facts are true for nearly all natural teeth:
The neck of the tooth has a more pronounced color than the incisive edge.
The incisive edge if not worn, is more translucent than the body of the tooth and is usually of a bluish shade (composed entirely of enamel)
The upper central incisors are lightest teeth in the mouth followed by the laterals and canines. Posterior teeth are usually uniform in color.
Teeth darken slightly with age.

69. Advantages of non anatomic teeth
1. Comfortable 2. The allow greater range of movements which is necessary in patients with mal-related jaws (as those with Para functional jaw habits ). 3. Non anatomic teeth exerts less horizontal or torquing forces, so they are used with flat ridge cases. 4. Centric record only is needed.

70. Non-Anatomic Teeth
No overbite
Normal overjet (1-2mm)