1. A bioengineered implant for a predetermined bone cellular response to loading forces.A literature review and case report. Misch CE. Bidez MW, Sharawy M J Periodontol 2001;72:1276-1286

2. 3.

Bone , systemic change, local mechanical factors.

Wolff 1982 bone adaptive properties mechanic stimuli :

• bone

• ( ) bone volume remaining bone

Cortical, trabecular bone modeling, remodeling

• Modeling formation resorption bone

• Remodeling formation resorption previous bone bone quality

Bone modeling and remodeling strain mechanical environment

4.

Bone ( )

• lamellar bone

• woven bone

• composite bone

• bundle bone

bone type osseointegrated implant

• Lamellar bone bone type most organized, highly mineralized, strongest load bearing bone

• Woven bone bone type unorganized, less mineralized, less strength immature bone

• Composite bone lamellar, woven bone cortical bone endosteal, periosteal surfaces

5. 6.

Cortical bone fractures 10,000 20,000 microstrain (1~2% deformation) bone

Microstrain levels remodeling rate

• bone cell membrane mechanosensory system

• bone cellular behavior bone cells strain deformation mechanical environment

microstrain bone cell membrane ion membrane channel load

7. Frost 1989 (strain) 4 microstrain zone

pathologic overload zone acute disuse window bone volume

• Pathologic overload microfracture repair net bone resorption

• Disuse zone remodeling bone mass

• Mild overload zone higher bone turnover rates more woven bone

• Adapted window organized, mineralized lamellar bone

pathologic overload zone

mild overload zone

adapted window

acute disuse window

8.

Remodeling rate(bone turnover) (new bone) existing bone bone

• Bone remodeling rate (BRR) (volume) (percentage)

• woven bone 60microns ( 10 -6 m) Lamellar bone 1~5microns

• higher BBR woven bone

create maintain mechanical challenge bone mass adaptive window zone more reactive woven bone Mild overload zone higher BRR

9.

Adapted window zone organized, highly mineralized lamellar bone

• adapted window dental implant bone more mature periodic changes more resistant

• adaptive window zone Implant-bone interface adjacent to away from implant BRR

BRR implant interface strength Implant-bone interface risk degree

Higher risk higher turnover rates bone interface less mineralized, less organized, weaker

10. Implant interface remodeling 11.

implant Interface remodeling dental implant original bone bone interface

• healing implant interface bone 4 mature vital bone osteoblasts deposit 70% mineral

• 30 mineral deposition 8 secondary mineralization

mineral density bone age

• Bone mineralization bone implant interface

implant load interface remodeling

• Implant long-term maintenance interface continuous remodeling

new bone sustained microfractures fatigue bone cyclic loading

Frost 1960 microdamage elevated remodeling activity

12.

rib long bone shaft diaphysis cortical bone 2~10% remodel (Parfitt 1983 )

jaw bone BRR rib long bone shaft diaphysis cortical bone 40 (Tricker 1977 )

• BRR

Verborgt 2000 (ulna) fatigue loading microcracks TUNEL-positive osteocytes

• Intracortical resorption 300

• microdamage osteocyte apoptosis subsequent bone remodeling

Screw-type implant cortical bone microdamage insertion pullout forces microdamage implant thread design

13. bioengineering of an implant design

implant design bioengineering loading adapted window zone microstrain loading interface lamellar bone implant interface BRR

implant interface strain implant lamellar bone remodeling rate

14.

3

• anatomical dimension limitation, macrodesign criteria

• mechanical properties.

Engineering strain-controlled bone turnover.

15.

shear loading square thread design axial loading body

• microstrain square thread 4 thread pitch

16.

1994 University of Alabama at Birmingham(UAB) research team load bioengineered implant .

UAB BioHorizons implant system Maestro implants Lekholm,Zerb,Misch

1995 bioengineering thread design.

1996 6 5

• bioengineered implant

loaded BRR

17. 18.

35 ,1996

• Skeletal Class II, /

1996 June, symphysis donor graft alloplast allograft sinus graft.

1997 January 4 bioengineered implants(Maestro, BioHorizons implant system) 3 bioengineered implants ( 4mm; 11~13mm)

1997 August

19. 20.

11

21.

bone labeling protocol

• BRR 2 bone labels (tetracycline 500mg)

trephine bur

• tetracycline

• ( m / time period)

22.

remodeling site

• tetracycline

2 BRR 4.866 m 0.16/

1 2mm threads

woven bone remodeling rate

23. 24.

Frost 1983 bone repair modeling remodeling trauma( ) regional acceleratory phenomenon(RAP)

unloaded control implants

1.5 RAP BRR.

25.

Isidor 1996,1997

• loading occlusal overload rigid fixation

• • 8 screw-shaped implants 4 8 supra-occlusal contacts 10

• • 5/8 with supra-occlusal loads mobile

• • rigid fixation failure fatigue microfracture repair potential

Rangert 1995 prosthetic load implant component implant body fracture.

crestal bone loss excessive load overload .(Hoshaw 1994 ,Misch 1995 ,Quirynen 1992 )

26.

Excessive stress microfracture microstrain interface pathologic mild overload zone

Microstrain environment prosthodontic loading turnover rate

Overload zones(Frost 1989 ) lamellar bone woven bone reactive woven bone weaker more flexible biomechanical mismatch.(Misch 1999 )

• biomechanical mismatch strain

rigid fixation interface bone prosthodontic load microdamage

27. 28.

functionary unit elevated BRR (Garetto 1995 )

• mild overload zone.

BRR implant body design surface condition

• Cooper 1991 ( ) Roberts 1997 macrosphere surface(Endopore, Innova) elevated turnover rate

• smooth collar designs crestal bone loss disuse atrophy overload (Vaillancourt 1995 )

• more stress crestal regions Cooper greater strain condition BRR

29.

Roberts 1997 asymmetric implant thread design(Steri-Oss, Nobel Biocare) symmetrical threaded surface(Branemark, Nobel Biocare)

• (Steri-Oss, Nobel Biocare) reverse buttress thread shape(680%BRR) symmetrical threaded surface(Br nemark, Nobel Biocare) V-shaped thread higher bone contact reduced bone turnover rate(500%).

30.

Barbier 1997 implant-supported prostheses non-axial load axial load

• axially loaded implants non-axially loaded implant greater BRR

Non-axial loads axial loads stress (Misch 1994 )

• higher cellular response( osteoblasts inflammatory cells) under non-axial shear loading condition

31.

Burr 1993 tibial metaphyseal bone HA/TCP-coated uncoated titanium implants cylinder implants remodeling activity

• titanium surface implants greater bone turnover rates

• Cook 1987 Thomas 1987 HA coatings greater interface strength greater bone mineralization remodeling rate

HA-coated implants functional loading 9~10 morphological changes(Baltag 2000 )

• HA stress values

Hoshaw 1992 titanium-threaded implants axial tensile loading higher remodeling rates less mineralized bone( loading )

32.

Baumgarder 2000 bone quality-based implant system

• 6 8 implants quantitative histomorphometric analysis 53.7 4.2 bone contact

• woven bone formation, threads mature formed osteons

• threads mm bone turnover rate

• Loading 6 2 remodeling cycle lamellae compaction

• vertical chewer, bruxism clenching

• bone turnover rate.

33.

Loading BRR.

Roberts 1990 3

• Bone-implant 30 remodeling

• 40 remodeling adapted window zone

• (