1. Tooth Loss and Prosthetic Appliances
REF: Prosthodontics. Principles and Management Strategies.1996, Owall, Kayser and Carlsson, Chap. 3, pp
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2. Tooth – type and function
Aesthetic units
Occlusal units
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3. Functional classification of the 28 teeth or 14 pairs of antagonistic units
Location
Name
Number
Anterior area
Aesthetic units 6
Premolar area
Occlusal units 4
Molar area
4 (81)
Total
Functional units
14 (181)
1 in premolar equivalents.
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4. Healthy or Physiological Occlusion
Absence of pathologic manifestations
Satisfactory function
Variability in form and function
Adaptive capacity
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5. Functional assessment of the different tooth types
Anteriors
Premolars
Molars
Biting + -
Chewing
Speech
Aesthetics
Stability of:
TMJ
Dental arch
+ = Prime involvement; - = No, or secondary involvement. (Stuart and Stallard,1960)
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6. Can anterior teeth and premolars compensate for the function of the molars? (shortened dental arch)
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7. Schematic representation of the aetiology of an impaired dentition
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8. Natural history of the dentition in high-risk groups
Healthy dentition
Minor changes (intact occlusion)
Major changes (impaired occlusion)
Edentulousness (lost occlusion)
Loss of alveolar bone
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9. Biological and functional aspect of tooth loss
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10. Changes following tooth loss Pathological condition
Adaptation or
Pathological condition
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11. Spontaneous closure of open space in a 32-year-old man after loss of tooth 11 at the age of 12 years due to trauma
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12. Effects of tooth loss on the remaining dentition
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13. Radiographs of a 52-year-old woman (1992) showing structural and functional stability of an extreme shortened dental arch (8 occluding units) after 20 years (a) and 28 years of function (b).
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14. Local factors influence the consequences of tooth loss
Location of the lost tooth
Number of the lost teeth
Intercuspation
Periodontal condition
Position of the tongue
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15. Systemic factors influence the consequences of tooth loss
Age
Adaptive capacity
General resistance
Neuromuscular tolerance
Psychological condition
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16. Sequelae of tooth loss Migration Unilateral chewing Alveolar bone loss
Occlusal interference
Loss of proximal contact
Overloading of anteriors
Loss of VD
TMD
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17. General Pattern of Tooth Loss
Molars then premolars.
Lastly the lower anteriors.
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18. Possible migration after loss of tooth 36
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19. (a)
(b)
(a) A new occlusal balance was established after loss of teeth 46 and 47 at the age of 22 years in a 28-year-old woman (1971), followed during 11 years. (b) alveolar bone height in 1971 and 1984.
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20. Loss in the anterior region
Disturbed aesthetics
Disturbed speech
Affected psychosocial function
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21. Patterns in partial edentulism
Eichners classification (no. of remaining occlusal supporting zones)
Simple classification of impaired dentitions
Uncomplicated
Complicated
Partial edentulism
Tooth boundspace
Shortened dental arch
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22. The Eichner Index, based on supporting zones of antagonist contacts in premolar and molar regions (Helldén et al., 1989) A1 A2 A3 B1 B2 B3 B4 C1 C2 C3
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23. Uncomplicated tooth-bound space in the left mandible
Complicated tooth-bound space, showing migration of remaining teeth
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24. Uncomplicated shortened dental arch
Complicated shortened dental arch: migration of remaining teeth, loss of vertical dimension and dislocation of condyle
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25. Compensation of tooth loss
Chewing where most occlusal contact
More chewing strokes
Swallowing of larger particles
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26. Migration in tooth bound spaces
Distally located teeth drift and tip mesially
Mesially located teeth drift and tip distally
Extrusion with no opposing contact
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27. Migration Premature contact and interferences Adaptation
Pathological condition (TMD)
(close in new position)
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28. Shortened dental arches
Premolar dental arch
Extreme shortened dental arch
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29. Complicated shortened dental arch: migration of remaining teeth, loss of vertical dimension and dislocation of condyle
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30. Masticatory function measuring
Objectively
Chewing test
(masticatory performance)
MP (no. of occlusal units ability)
Subjectively
Questionnaire or interview
(masticatory)
10 occluding pairs
will be sufficient
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31. Schematic representation of the relationship between masticatory function and dental arch length (expressed in occlusal units)
1 = Masticatory ability (perceived ease of chewing)
2 = Masticatory performance
A = Area of sufficient masticatory function
B = Turning range
C = Area of insufficient masticatory function
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32. Stability of premolar dental arch
Occlusal contact in IP
Overbite
Interdental spacing
Attrition and alveolar bone support
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33. Effect of periodontal problems on shortened dental arches
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34. Oral comfort Absence of pain Satisfactory masticatory ability
Acceptable aesthetics
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35. Relationship between oral function and shortened dental arches
1 = Contact between anterior teeth in IP
2 = Alveolar bone height
3 = Interdental contact between anterior teeth; absence of mandibular dysfunction
4 = Chewing capacity
5 = Aesthetics
A = Area of sufficient and function (adaptation)
B = Turning range
C = Area of insufficient oral function
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36. Dental arch support and TMJ?
Posterior tooth loss
TMJ osteoarthrosis
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37. Implications for prosthetic treatment
28 tooth syndrome
Over treatment
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38. To maintain a healthy natural functioning dentition for life
Dental Care Aim
To maintain a healthy natural functioning dentition for life
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39. “The exact number of teeth each individual need, can not be ascertained by the dental profession.”
“If patient manage well with any number of teeth, then there is no reason to recommend prosthetic appliances.”
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40. Oral Function Level
Optimal
Sub-optimal
Minimal
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41. Required oral functional level in relation to age, expressed as the minimum number of occluding pairs of teeth (arch length)1
Age (years)
Functional level
Occluding pairs
20 – 50
I: Optimal 12
40 – 80
II: Suboptimal
10 (SDA)
70 – 100
III: Minimal
8 (ESDA)
1 SDA = Shortened dental arch; EDSA = Extreme shortened dental arch
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42. The Shortened Dental Arch Concept
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43. The occlusal preservation target in high-risk groups
I = Complete dental arch (optimal function)
II = Shortened dental arch (suboptimal function)
III = Extreme shortened dental arch (minimal function)
A = High-risk factors (caries, pockets)
B = Limiting factors (restricted finances)
C = Patient factors (poor general health)
The occlusal preservation target in high-risk groups
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44. The prosthetic treatment target in high risk groups
The prosthetic treatment target in high risk groups. The number of teeth to be restored is dictated by the needed functional level.
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45. Teeth should be replaced for
Aesthetics
Functional comfort
Occlusal stability
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46. Lecture No.2 Pre-edentulism
Ref: Prosthodontics. Principles and Management Strategies. 1996, Owall, Kayser and Carlsson, Chap. 4, pp
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47. Natural history of the dentition in high-risk groups
Healthy dentition
Minor changes (intact occlusion)
Major changes (impaired occlusion)
Edentulousness (lost occlusion)
Loss of alveolar bone
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48. The traditional restorative approach in prosthetic dentistry
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49. Pre-edentulous situation
Just a few (non-strategic) teeth are left with poor prognosis.
The distribution of the remaining teeth in the dental arches is often unfavorable  oral function cannot be performed adequately.
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50. Preventive prosthetic treatment for the pre-edentulous patient=
Postponing of tooth extraction to prevent bone loss
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51. Principles of preventive prosthetic treatment for the pre-edentulous patient
Treatment planning and timing of tooth extraction
Shortening the dental arch with preservation of occluding pairs of teeth
Use of an overdenture
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52. Treatment planning and timing of tooth extraction
Condition of residual tooth
Age
Postponement of extraction delays the reduction of the alveolar ridge
Extraction of teeth with severe periodontitis (targeted extraction)  less bone resorption
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53. Shortening the dental arch with preservation of occluding pairs of teeth
Free-end RPD X shortened dental arch
If no remaining occluding pairs  the remaining teeth will cause damage to opposing edentulous jaw
Preventive implantology
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54. Due to the removal of the antagonistic tooth in the mandible, the solitary maxillary tooth has caused bone loss in the mandible
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55. (a) An example of a patient with a dental situation with no occluding pairs of teeth (natural versus artificial teeth) and severe alveolar bone resorption of the edentulous maxilla.
(b) The teeth in the mandible are functionally “locked”. Every movement of the jaw causes the lower teeth to damage the edentulous maxilla via the upper denture.
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56. A dentate maxilla opposing an edentulous mandible should always be avoided. A situation of natural teeth versus artificial teeth has led to severe alveolar bone loss of the mandible
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57. Use of an (immediate) overdenture
Preservation of the alveolar ridge
Preserving lower canines
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58. (a) Orthopantomogram of a 45-year-old female patient (1987) with an edentulous maxilla and periodontal disease in the mandible. In spite of the poor periodontal condition, it was decided to make a complete immediate overdenture in the lower jaw, while retaining four abutment teeth.
(b) The situation 6 years after treatment (1993). Good oral hygiene and plaque control using chlorhexidine (Hibigel®).
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59. Schematic summary of the treatment planning by a pre-edentulous patient with a residual mutilated dentition
motivation, instruction
treatment of periodontium and caries
“targeted” extractions
removable partial (immediate) denture
recall
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60. (a) In a 61-year-old woman with poor oral hygiene, a complete immediate overdenture, while retaining both lower canines, was inserted in 1986.
(b) In the clinical situation more than 7 years later (1993), oral hygiene is good, resulting in a healthy periodontium and hardly any alveolar bone loss.
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61. Assessment of the pre-edentulous dentition for overdentulous treatment
Caries
Periodontal considerations
Prosthetic consideration
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62. Extensive and active caries
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63. Periodontal consideration
Mobility
Type of bone loss
Extraction, subgingival curettage
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64. Samar Al Saleh

65. Endodontic Consideration
Single rooted canal and apical radiolucency
Successful endo treated tooth
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66. Prosthetic Considerations
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67. If the vertical jaw relationship shows sufficient denture space, abutment teeth which are (more or less) opposing should be retained
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68. Prosthetic considerations in the selection of abutment teeth
If possible always
If opposing teeth are present in the mandible in order to avoid “natural vs artificial teeth”
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69. Location of the abutment teeth
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70. The division of the jaw into four zones to facilitate the selection of abutment teeth
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71. Examples of the distribution of abutment teeth within the dental arch
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72. Canines as an overdenture abutments
Longest teeth
Strategic position
Oval-shaped root
Easy endo treatment
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73. (b) In the clinical situation more than 7 years later (1993), oral hygiene is good, resulting in a healthy periodontium and hardly any alveolar bone loss.
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74. Distribution of abutment teeth over the upper and lower jaw
Situations in which teeth oppose an edentulous part of the jaw should be avoided.
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75. Many pre-edentulous situations between the lower and upper jaw are undesirable from a prosthetic point of view (green in illustration). The figure indicates which dental situations offer a good starting point for making an overdenture.
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76. A “targeted extraction strategy”, possibly combined with the making of an overdenture, enables the balance of forces between the dental arches to be restored. (NB The use of dental implants makes other combinations possible)
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77. Dental implants as abutment teeth for overdentures
(a) The use of implants in the lower jaw restores the balance between the dental arches.
(b) Reduction of tooth material in the lower jaw can be avoided by inserting implants in the upper jaw.
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78. The main goal in “preventive prosthodontics” is the preservation of oral function for life. Dental implants can effectively “reverse” complete edentulousness and restore oral function
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79. Submerged roots and submucosal implants
Root of fractured teeth
Filling the socket with biocompatible material
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80. Orthopantomogram of a patient with submucosal implants (calcium hydroxyapatite), inserted immediately after extraction.
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81. Depending on the individual rate of resorption, the upper surface of the submucosal implants will sooner or later protrude above the level of the jawbone with dehiscence of the mucosa.
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