progressive bone loading in dental implants

1. Progressive bone loading
Ashwini Narayankar
Reader, Department of Prosthodontics
S B Patil Dental college, Bidar

2. Progressive bone
loading
Bone density Bone implant
interface
Progressive
bone loading
protocol
Procedure
Partially
edentulous
arches
Completely
edentulous
arches

3. • Crestal bone loss – in 1st year
• 5.9% of implants restored were lost from
the impression to initial delivery of the
prosthesis
• Root laboratory: statistics report on implant and
prosthesis failure during the first year, 1992, Leawood,
Kan

4. Bone density
• Wolff’s law
• Every change in the form and function of
bones or of their function alone is followed
by certain definite changes in their
internal architecture, and equality definite
alteration in their external confrontation,
in accordance with mathematical laws

5. • Generalized loss of bone volume and
density – tooth loss
• Decreased microstrain
• Orban B: Oral histology and embryology, 3rd edition, St
Louis, 1953, Mosby, pp 87-104

6. • Bone cells sense mechanical load
• Cell level strains are 10 times greater than
tissue level strains
• Cellular mechanism – membrane
deformation, intracellular and extracelluar
action
• Cowin SC et al, bone remodeling I, theory of adaptive
elasticity 1976;6:313:326

7. • Misch et al
• D1 – 100%
• D2 – 75%
• D3 – 50%
• D4 – 25%

8. Bone implant interface
• Continuously loaded – stable
• Lamellar bone
• Highly organized
• 1 yr to mineralize
• Woven bone
• Unorganized
• Fastest
• 16 wks – 70% mineralized

9. Progressive bone loading protocol
• Increases density
• Decreases failure
• Decrease crestal bone loss
Occlusal
contacts
Prosthesis
design
Occlusal
material
Diet
Time

10. Time
• Initial implant placement and stage II
uncovery – 3 to 8 months
• Healing time
• D1 – 3 months
• D2 – 4 months
• D3 – 5 months
• D4 – 6 months

11. Time
• Gradual loading
• D1 – 1 week
• D2 – 2 weeks
• D3 – 3 weeks
• D4 – 4 weeks or more

12. Diet
• Initial healing phase
• Avoid chewing in that area
• After uncovery
• Soft diet – pasta and fish – 10psi
• Initial delivery of prosthesis
• Meat – 21psi
• Final restoration
• Raw vegetables – 27psi

13. Occlusal material
• Initial steps – no occlusal material
• Acrylic material

14. Occlusion
• Initial healing – no occlusal contacts
• Transitional prosthesis – out of occlusion
• Final restoration – occlusal contacts

15. Prosthesis design
• Initial healing – no load
• 1st transitional prosthesis
• No occlusal contact and no cantilevers
• Splint implants – reduce stress
• 2nd transitional prosthesis
• Occlusal contacts on implants and not on
cantilevers
• Final restoration
• Narrow occlusal table implant protective
occlusion

16. Progressive loading phases
• Stage II uncovery
• Evaluate clinical mobility, bone loss, zones
of attached gingiva, sulcus depth
• Permucosal extension – 2mm
• No loading

17. • Partially edentulous arch
• Not to wear denture
• Anteriors – 7 mm diameter hole
• Completely edentulous arch
• 5 mm diameter relieve
• Tissue conditioner – few mm relieved

18. Procedure
Final delivery and evaluation
Initial abutment
selection and primary
impression
Metal superstructure try in
and transitional prosthesis
II
Initial insertion of final
prosthesis
Final impression and
transitional prosthesis I

19. Step Procedure Diet Occlusal
material
Occlusal contacts
1 Healing abutments and
primary impression
Soft 0 0
2 Transitional prosthesis I ,
final impression
Soft Acrylic P – none
C – no cantilever
3 Transitional prosthesis II
and metal try in
Soft Acrylic Contacts on
implants and not
on cantilevers
4 Final prosthesis, adjust
occlusion
Harder Metal or
porcelain
Implant protected
occlusion
5 Final prosthesis,
cementation
Harder Metal
porcelain
Narrow occlusal
table

20. First appointment
• Initial abutment selection and primary
impression
• Remove permucosal extension
• Insert abutments or indirect impression
transfers or direct impression transfer
• Finger pressure

21. • Make impression – implant body analogs
• Reinsert healing caps
• Occlusal bite registration in centric relation
• Instruction – not to chew in the region
and brush with chlorhexidine

22. Laboratory phase I
• Pour the impression
• Mount it with opposing arch with bite
• Prepare implant abutments for height,
parallelism and position

23. • Fabricate first transitional prosthesis
• Out of occlusion

24. Second appointment
• Final impression and
transitional prosthesis I
• After 1 – 4 wks
• Remove permucosal
extension
• Abutment screw – finger
pressure – 10N/cm

25. • Radiograph
• Final abutment preparation

26. • Final impression
• Record centric relation registration
• Face bow record

27. • Lute first transitional prosthesis with
noneugenol zinc oxide cement with no
occlusal contacts
• Modified – petroleum jelly

28. • Instructions
• Avoid that area while eating
• Soft food

29. Laboratory phase II
• Pour final impression
• Mount models
• Full contour wax up and
cut down of 2 mm for
porcelain
• Metal superstructure
• Occlusal index to
indicate occlusal
registration

30. Third appointment
• Metal try in
• 1 – 4 wks
• Remove 1st transitional prosthesis
• Metal superstructure is tried in
• Verify centric relation with occlusal acrylic
index
• If not matching – new registration with
addition silicone

31. • Second transitional prosthesis
• New or modification of first
• Modified occlusal table
• Addition of acrylic resin on occlusal
contact areas
• No lateral excursive contacts

32. Laboratory phase II
• Final prosthesis
• Occlusal contacts in long axis of implant

33. Fourth appointment
• Initial prosthesis delivery
• 1 to 4 wks
• Remove transitional prosthesis
• Insert final restoration and evaluate
• Occlusal adjustment with no occlusal
contacts in excursions

34. • Radiograph as baseline
• Harder food - meat

35. Fifth appointment
• Final delivery and cementation
• 4 weeks
• Remove the prosthesis
• Evaluate soft tissue condition
• Cementation of the final prosthesis
• Diet – hard foods – raw vegetables
• Maintenance – 3 to 4 months

36. Completely edentulous patient
Final delivery and evaluation
Initial abutment
selection and primary
impression
Metal superstructure try in
and transitional prosthesis
II
Initial insertion of final
prosthesis
Final impression and
transitional prosthesis I

37. First appointment
• Initial abutment selection and primary
impression
• Treatment prosthesis – OVD
• Clear template over treatment prosthesis
• Bite registration to opposing arch
• Insert abutments
• Minor corrections

38. • Fill the template with addition silicone and
make impression
• Remove abutments, attach abutment
analogs
• Reinsert permucosal extension
• And relieve soft liner

39. • Very soft food
• Remove denture in night
• Parafunction – major concern
• Implants not splinted

40. Laboratory phase I
• Pour primary impression
• Mount the casts
• Adjust implant length, angulations and clearance
• Wax up using denture teeth
• Clear template

41. • Transitional acrylic prosthesis
• Using clear template
• No posterior cantilever
• Pontics – out of occlusion
• Implant loaded axially
• No posterior contacts during lateral excursions

42. • Occlusal rims over the abutments

44. Second appointment
• Final impression and transitional
prosthesis I
• Remove permucosal extension
• Insert final abutments
• Clear template of final wax up is placed
• Minor corrections

45. • Insert 1st transitional prosthesis
• Make an final impression

46. • If not ideal
• Occlusal rims are adjusted
• Centric relation record is made
• Anterior tooth shape and size is selected
• Face bow record done
• Non eugenol cement
• Occlusal contacts
• Diet – very soft

47. Laboratory phase II
• Mount master cast using face bow record and
occlusal registration
• Index of incisal edge and facial tooth form of
temporary or wax rim
• Wax up of final restoration
• Cut back of 2mm for porcelain
• Metal framework
• White wax to evaluate anteriors
• Acrylic occlusal index to check OVD

48. Third appointment
• Metal try in and transitional prosthesis II
• Metal framework try in
• Acrylic occlusal index – centric relation and OVD
• White wax – evaluate anterior esthetics
• Final crown contour and shade selection

49. • Modify first transitional prosthesis
• Eliminate nonworking and working
occlusal contacts
• Softer diet

50. Fourth appointment
• Initial delivery
• 2 to 4 wks
• Adjust final occlusion
• Implants loaded axially
• OPG and bite wing R/g
• Hard food

51. Fifth appointment
• Final delivery
• 4 wks later
• Improve difficult access for hygiene
• Soft tissue health
• No posterior contacts during lateral
excursions
• Zinc phosphate cement
• Maintenance every 3 – 4 months

52. Clinical assessment
Bone divisions Periotest values (PTV)
D1 bone – uncovery
After progressive loading
Average PTV decrease
-8 to -3
-8 to -4
<1
D2 bone - uncovery
After progressive loading
Average PTV decrease
D3 bone - uncovery
After progressive loading
Average PTV decrease
-5 to 0
-8 to 0
1
-3 to +1
-5 to 0
2
D4 bone - uncovery
After progressive loading
Average PTV decrease
-2 to +6
-4 to +2
4

53. Crestal bone loss
• Progressive bone loading
• 2 months – 0.13 ± 0.05 mm
• 4 months – 0.18 ± 0.10 mm
• 6 months – 0.24 ± 0.12 mm
• 12 months – 0.32 ± 0.16 mm
• Control group
• 2 months – 0.31 ±0.08 mm
• 4 months – 0.35 ± 0.13 mm
• 6 months – 0.41 ± 0.22 mm
• 12 months – 0.47 ± 0.47 mm

54. References
• Misch CE, dental implant prosthetics,
3rd edition, 2008, Elsevier publication, St.
Louis, Missouri, pp 511 - 530
• Root laboratory: statistics report on
implant and prosthesis failure during the
first year, 1992, Leawood, Kan

55. • Orban B: Oral histology and embryology,
3rd edition, St Louis, 1953, Mosby, pp 87-
104
• Cowin SC et al, bone remodeling I, theory
of adaptive elasticity 1976;6:313:326