Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
www.indiandentalacademy.com
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

www.indiandentalacademy.com
Definition
Process of analysis and determination of loading and
deformation of bone in a biological system.
Role
Natural t...
Types


Reactive



Therapeutic

Reactive Biomechanics
Any prosthesis that increases implant loading.

www.indiandentala...
Therapeutic Biomechanics
Process of remediating each biomechanical factor in order to
deiminish implant overlaoding

www.i...
Interrelated Factors
Analyzed during diagnosis and treatment planning and
maintained in a state of equilibrium.


Biomech...
Methods of Analysis
 Finite element analysis – Siegele 1989, Chelland 1991
Determined the distribution and concentration ...
 Birefringence Analysis
Done on plastic model utilizing polarized monochromatic light.
 Load Measurement : Lundreg 1989,...
FORCE
Definition
Any application of energy, either internal or external to a
structure, that which initiates, changes or a...
Magnitude
Anatomic region and state of dentition.
Craig, 1980
Molar

-

390 – 880N

Canine

-

453N

Incisor

-

222N

Par...
Duration
Mastication

-

9mt/day with 20 to 30 psi

Swallowing

-

20mt/day with 3 to 5 psi

Type
Compressive, Tensile and...
Direction

On centric vertical contact

Angle load

Axial load

Greater tensile & shear stress

Greater compressive
stress...
Magnifying Factors
Applied Load  Torque
Includes,
 Extreme angulation
 Cantilevers
 Crown height
 Parafunction
 Bone...
Torque / Moment Load / Bending Load
Product of inclined resultant line of force and distance from
center of rotation.
Torq...
FORCE DISTRIBUTION
Chelland 1991,
&
Reiger 1990

Weinberg, 1994

Natural teeth

Rigidly fixed

Periodontal ligament

Stiff...
FORCE DISTRIBUTION PRINCIPLES
System Components


Vertical element – tooth or implant



Connecting element



Supporti...
Flexible Medium

www.indiandentalacademy.com
Stiff Medium

www.indiandentalacademy.com
Flexible and Stiff Medium

www.indiandentalacademy.com
DIFFERENTIAL MOBILITY
Qualitative difference between the flexion of periodontal
ligament and stiffness of osseointegration...
Natural Teeth

Implant

Periodontal ligament - flexion

Rigidly fixed – stiff

Even force distribution

Concentration at...
 Elastic modiolus similar to bone

5-10times different
Therefore, with same load
Increase stress,
concentrates at crestal...
Forces acting on Implants


Occlusal loads during function



Para functional habits

Passive Loads



Mandibular flex...
TRAUMATIC FORCES OR IMPLANT OVER LOADING


Non passive prosthesis



Parafunction



Initial contact during maximum int...
FORCE DISTRIBUTION IN MULTIPLE IMPLANT PROSTHESIS
Splinting
 Natural tooth – Periodontal ligament – forced distribution
...
FORCE DISTRIBUTION IN COMBINED PROSTHESIS


Supported by both natural teeth and implants



Mode of attachment


Flexib...
FLEXIBLE ATTACHMENT


Tooth supported prosthesis – Female attachment



Implant supported prosthesis – Screw retained
Fl...
STIFF ATTACHMENT


Natural tooth – permanently cemented substructure

telescopic crown


Implant supported prosthesis – ...
DIAGNOSTIC FACTORS IN COMBINED PROSTHESIS
Standard Prosthesis design
Internal attachment placed in distal of natural tooth...
Recommended Prosthesis Design
One cantilever pontic from each segment
Flexible internal attachment
Drifting apart of segme...
FOUR CLINICAL VARIANT WITH IMPLANT LOADING
Includes


Cuspal inclination



Implant inclination



Horizontal Implant O...
Cuspal Inclination
Increase in 10°  increased 30% torque
Implant Inclination
Increase in 10°  Increased 5% torque

www.i...
Horizontal Implant Offset
Increase in 1mm  increased 15% torque

Apical Implant Offset
Increase in 1mm  Increased 5% tor...
Staggered Implant Offset – Rangert 1993
Staggered buccal and lingual offset
Tripod Effect
Compensates torque
Implant place...
Weinberg 1996
In maxilla, lingual offset - increased 24% torque
Buccal offset - Decrease 24% torque
Maxilla

-

Tripod –in...
Weinberg, 1996
In posterior working side, occlusion.

Produces buccally

inclined resultant line of force on maxilla and l...
THERAPEUTIC BIOMECHANICS


Decrease cuspal inclination
It reduces the distance between implant and resultant line of

for...


Cross occlusion
Buccolingual relation  cross occlusion
Reduces horizontal implant offset
Reduces torque

www.indianden...


Implant Position
Implant head as close to center line of restoration –

Reduces horizontal offset.

www.indiandentalaca...
PHYSIOLOGIC VARIATION – CENTRIC RELATION
Kantor, Calagna, Calenza, 1973.
Centric relation record show physiologic variatio...


Anterior Vertical Overlap
Steep vertical overlap

Extreme Torque

www.indiandentalacademy.com

Less steep

Less Torque
BIOMECHANICS AND RESORPTION PATTERN
Posterior Mandible
Bone resorbs along root inclination
Therefore, posterior mandible –...


Therapeutically
Can be done by



Reduced cusp inclination



Implant head close to centre line of restoration



An...


Posterior Maxilla

Reactively


Restricted maxilla



Location of sinus



Buccal cortical plate fracture



Unfavo...
Therapeutically


Cuspal inclination – reduce



Head of implant close to center of restoration



Angled / custom – re...
Anterior Maxilla
Reactively
Esthetically

-

Labially Proclined

-

Steep vertical overlap

www.indiandentalacademy.com
Therapeutically


Lingual horizontal stop – redirect the force as vertically as

possible.


Angled abutment



Implant...
COMPLETE EDENTULISM AND BIOMECHANICS


Screw loosening not common these patients
Implant placed across and around arch
Cr...
WIDER IMPLANTS
Developed by Dr.Burton Langer
Advantages


Increase in surface area



Limited bone height



Upon remov...
BONE DENSITY AND BIOMECHANICS
Density

∞

Strength

∞

Amount of contact with implant

∞

Distribution and dissipation of ...
BONE DENSITY AND TREATMENT PLAN MODIFIER


Prosthetic factors



Implant number



Implant – Macrogeometry



Implant ...
PROSTHETIC FACTOR
As density decreases, biomechanical load should also
decreased


Shortened cantilever length



Narrow...
Implant Number
Increase in number  Increase in functional loading area
Implant Macrogeometry
Length


D1

-

10mm



D2...
Width


Increase in width – increase in surface area



1mm increases  30% increase in surface area



D3 & D4  wider...
Progressive Loading
Misch 1990
Gradual increase in occlusal load separated by a time
interval to allow bone to accommodate...
Time
Two

surgical

appointments

between

initial

placement and stage II uncovery may vary on density.


D1

-

5 Month...
Occlusal Material
Initial step – no occlusal material placed over implant
Provisional – Acrylic – lower impact force
Final...
Prosthesis Design
First transititional –

No occlusal contact
No cantilever

Second transititional - Occlusal contact
with...
SINGLE TOOTH IMPLANT AND BIOMECHANICS


Requires good bone support



Control of occlusal lever parallel to long axis

...
When space exceeds 12mm

When space less than 12mm

www.indiandentalacademy.com
When space exceeds 8mm with limited width

Should not be placed off center

www.indiandentalacademy.com
Posterior Triangular Zone


Active zone



Occlusal loading parallel to long axis

www.indiandentalacademy.com
Cantilever Prosthesis and Biomechanics


It result in greater torque with distal abutment as fulcrum.



May be compared...
Arch form
English 1993 – AP Spread


Cantilever length = AP spread x 2.5



Tapering

-

canine and posterior implants w...
Tapering  Ovoid  Square

Less dense bone  Anterior cantilever with prosthesis  Distal
implants, placed to increase AP-...
CANTILEVER FIXED PARTIAL DENTURE



Sufficient bone height exist to place long implant,

Avoid contact on central incisor...


Group function - lateral movement



Avoid loading on canine



Lateral guidance provided by central and lateral inci...
Two implant supporting a first molar and 2nd premolar with 1st
premolar cantilever  Active cusp eliminated  canine palat...
Three implants placed with

Two implants  risky

2nd premolar as cantilever

and /or contraindicated

www.indiandentalaca...
MANDIBULAR FLEXURE
Picton 1962
Stated that mandibular move towards midline on opening 
Because of external pterygoid musc...
FLEXION
Implant

-

0.1mm

Natural teeth

-

0.5mm

mandible
10 to 20 times

Complete cross arch splinting of posterior mo...
www.indiandentalacademy.com
FATIGUE FAILURE
 Characterised by dynamic cyclic loadind
 Depends on – biomaterial
geometry
force magnitude
number of cy...
Biomaterial
 Stress level below which an implant biomaterial can be
loaded indefinitely is referred as endurance limit.
...
Implant geometry
 Resist bending & torsional load
 Related to metal thickness
 2 times thicker – 16 times stronger
Forc...
IMPLANT DESIGN & BIOMECHANICS



Ti alloy offers best biomechanical strength & biocompatability
Bending fracture resista...
www.indiandentalacademy.com
Thread pitch

Thread depth

www.indiandentalacademy.com
Depth –distance between major & minor diameter of thread

www.indiandentalacademy.com
Implant macrogeometry
Smooth sided cylindrical implants – subjected to shear
forces
Smooth sided tapered implants – plac...
Implant length
Increase in length –Bicortical stabilisation
Maximum stress generated by lateral load can be dissipated b...
Crestal module design
Smooth parallel sided crest –shear stess
Angled crest module less than 20 degree-Increase in bone ...
Larger diameter & angulated crestal module design

www.indiandentalacademy.com
Surface Coating
-Titanium plasma spray
-Hydoxyapatite coating
Advantages
-Increase in surface area
-Roughness for initial ...
IMPLANT PROTECTED OCCLUSION


Occlusal load transferred within physiologic limit



Misch,1993
width of occlusal table d...
Posterior crest of maxilla medial to
Mandibular crest

Narrow occlusal table + reduced
Buccal contour permits oral hygiene...
Apical Design
Round cross-section do not resist torsional load
Incorporation of anti –rotational feature
-Vent hole- bon...
Maxillary lingual cusp & contour reduced
Reduce offset load from opposing natural tooth

Mandibular buccal cusp -

in widt...
www.indiandentalacademy.com
Occlusal material
Porcelain,resin,gold
Porcelain

-

esthetics, chewing efficiency

Gold

-

Impact force,chewing efficien...
IMPLANT ORAL REHABILITATION
Constitutes
 Muscle relaxation
Absence of articular inflammation
Stable condylar position
...
Organic occlusion components
Correct vertical dimension
Maximum intercuspation in centric relation
Adequate incisal & c...
Bruxism patients
Education & informed consent to gain co-operation in
eliminating parafunction
Use of night guard
- ante...
Final prosthesis
- narrow occlusal table
- centric occlusal contact aligned parallel to long axis
Important criteria
- a...
CONCLUSION
Biomechanics is one of the most important consideration
affecting design of the framework for an implant bone
p...
Bibliography
Implant & restorative dentistry- Martin Dunitz
Atlas of tooth & implant supported prosthesis-Lawrence A.
We...
www.indiandentalacademy.com
Leader in continuing dental education

www.indiandentalacademy.com
Upcoming SlideShare
Loading in …5
×

Implants bio mechanics /certified fixed orthodontic courses by Indian dental academy

3,016 views

Published on



The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.


Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078

Published in: Education, Business, Technology
  • Be the first to comment

Implants bio mechanics /certified fixed orthodontic courses by Indian dental academy

  1. 1. www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. Definition Process of analysis and determination of loading and deformation of bone in a biological system. Role Natural tooth and implants anchored differently in bone The loading of teeth, implant and peri implant bone of prosthetic superstructure Optimize the clinical implant therapy www.indiandentalacademy.com
  4. 4. Types  Reactive  Therapeutic Reactive Biomechanics Any prosthesis that increases implant loading. www.indiandentalacademy.com
  5. 5. Therapeutic Biomechanics Process of remediating each biomechanical factor in order to deiminish implant overlaoding www.indiandentalacademy.com
  6. 6. Interrelated Factors Analyzed during diagnosis and treatment planning and maintained in a state of equilibrium.  Biomechanics  Occlusion  Esthetics www.indiandentalacademy.com
  7. 7. Methods of Analysis  Finite element analysis – Siegele 1989, Chelland 1991 Determined the distribution and concentration of strain and deformation within implant and stated that force distribution to surrounding bone occurs at crestal bone and level of third screw thread. www.indiandentalacademy.com
  8. 8.  Birefringence Analysis Done on plastic model utilizing polarized monochromatic light.  Load Measurement : Lundreg 1989, Montag 1991 Precise data about forces exerted on Implant to supporting bone. Complicated - invivo Invitro- valuable  Bond strength between implant and bone : Schmitz 1991 Done it by test of shearing, expulsion and torsion. www.indiandentalacademy.com
  9. 9. FORCE Definition Any application of energy, either internal or external to a structure, that which initiates, changes or arrests motion. Related Factors  Magnitude  Duration  Type  Direction  Magnification www.indiandentalacademy.com
  10. 10. Magnitude Anatomic region and state of dentition. Craig, 1980 Molar - 390 – 880N Canine - 453N Incisor - 222N Parafunction - 1000Psi Colaizzi, 1984 Complete denture - 77 – 196N Carlsson & Haraldson, 1985 Denture with implant - 48 – 412N www.indiandentalacademy.com
  11. 11. Duration Mastication - 9mt/day with 20 to 30 psi Swallowing - 20mt/day with 3 to 5 psi Type Compressive, Tensile and Shear Cowin 1989 Bone - Strongest - Compression - 30% weaker - tension - 65% weakest – shear Compressive force - Maintain integrity Tensile and shear - Disrupts integrity www.indiandentalacademy.com
  12. 12. Direction On centric vertical contact Angle load Axial load Greater tensile & shear stress Greater compressive stress Misch 1994 30% offset load – Decreases compressive strength – 11% - Decreases tensile strength – 25% www.indiandentalacademy.com
  13. 13. Magnifying Factors Applied Load  Torque Includes,  Extreme angulation  Cantilevers  Crown height  Parafunction  Bone density Crown height - Increase in 1mm – 20% increase in torque. With same load, D1 Bone Accommodate D4 Bone Cannot accommodate www.indiandentalacademy.com
  14. 14. Torque / Moment Load / Bending Load Product of inclined resultant line of force and distance from center of rotation. Torque Natural tooth - = Force x Distance Apical 1/3rd Chelland, 1991 Implant - First third screw level. Force  Vertical - towards supporting bone  Lateral - away supporting bone – Creates lever arm torque www.indiandentalacademy.com
  15. 15. FORCE DISTRIBUTION Chelland 1991, & Reiger 1990 Weinberg, 1994 Natural teeth Rigidly fixed Periodontal ligament Stiff Flexion Concentrates at crestal bone Even force distribution & 1st 3 thread level Implant Increase Root length – increase in surface area - better force distribution. Implant length – Initial mobilization www.indiandentalacademy.com
  16. 16. FORCE DISTRIBUTION PRINCIPLES System Components  Vertical element – tooth or implant  Connecting element  Supporting medium – periodontal ligament or bone www.indiandentalacademy.com
  17. 17. Flexible Medium www.indiandentalacademy.com
  18. 18. Stiff Medium www.indiandentalacademy.com
  19. 19. Flexible and Stiff Medium www.indiandentalacademy.com
  20. 20. DIFFERENTIAL MOBILITY Qualitative difference between the flexion of periodontal ligament and stiffness of osseointegration. Micro movement Natural teeth with good bone Will move laterally approximately 0.5mm Measured occlusally. Micron Movement – Weinberg, Rangert, 1994 Implant can move laterally 0.1mm or less measured occlusally. www.indiandentalacademy.com
  21. 21. Natural Teeth Implant Periodontal ligament - flexion Rigidly fixed – stiff Even force distribution Concentration at crestal bone 0.5µm movement 0.1µm movement Shock absorber Rigid Reduces the magnitude of Increases the magnitude stress Occlusal trauma – No such warning signs only Signs of cold sensitivity, bone microfracture Wear facets, Pits, Drift away & mobility www.indiandentalacademy.com
  22. 22.  Elastic modiolus similar to bone 5-10times different Therefore, with same load Increase stress, concentrates at crestal bone Surrounding bone formed childhood Forms rapid and intense Lateral force – exert Lateral force exert Movement No movement Dissipates to apex Concentrates at crestal bone www.indiandentalacademy.com
  23. 23. Forces acting on Implants  Occlusal loads during function  Para functional habits Passive Loads   Mandibular flexure Contact with first stage cover screw and second stage permucosal extension.  Perioral forces  Non –passive prosthesis. www.indiandentalacademy.com
  24. 24. TRAUMATIC FORCES OR IMPLANT OVER LOADING  Non passive prosthesis  Parafunction  Initial contact during maximum intercuspation  Labial stresses generated during eccentric movements. Therefore,  Eliminate posterior contact during protrusion and lateral excursion.  Prosthesis come in contact only during intercuspation. www.indiandentalacademy.com
  25. 25. FORCE DISTRIBUTION IN MULTIPLE IMPLANT PROSTHESIS Splinting  Natural tooth – Periodontal ligament – forced distribution  Implant – stiff – no force distribution and only concentration at crestal bone www.indiandentalacademy.com
  26. 26. FORCE DISTRIBUTION IN COMBINED PROSTHESIS  Supported by both natural teeth and implants  Mode of attachment  Flexible  Stiff  Flexible – internal attachment  Stiff – when terminal abutments are implants www.indiandentalacademy.com
  27. 27. FLEXIBLE ATTACHMENT  Tooth supported prosthesis – Female attachment  Implant supported prosthesis – Screw retained Flexion Occurs Not Deleterious www.indiandentalacademy.com
  28. 28. STIFF ATTACHMENT  Natural tooth – permanently cemented substructure telescopic crown  Implant supported prosthesis – over crown, coping with temporary cement Tend to Loosen To eliminate, permanent cementation rather than fixed retrievability www.indiandentalacademy.com
  29. 29. DIAGNOSTIC FACTORS IN COMBINED PROSTHESIS Standard Prosthesis design Internal attachment placed in distal of natural tooth Differential mobility Natural tooth cannot support implant Increase in lever arm Increase Torque www.indiandentalacademy.com
  30. 30. Recommended Prosthesis Design One cantilever pontic from each segment Flexible internal attachment Drifting apart of segment Decreased Torque www.indiandentalacademy.com
  31. 31. FOUR CLINICAL VARIANT WITH IMPLANT LOADING Includes  Cuspal inclination  Implant inclination  Horizontal Implant Offset  Apical Implant Offset www.indiandentalacademy.com
  32. 32. Cuspal Inclination Increase in 10°  increased 30% torque Implant Inclination Increase in 10°  Increased 5% torque www.indiandentalacademy.com
  33. 33. Horizontal Implant Offset Increase in 1mm  increased 15% torque Apical Implant Offset Increase in 1mm  Increased 5% torque www.indiandentalacademy.com
  34. 34. Staggered Implant Offset – Rangert 1993 Staggered buccal and lingual offset Tripod Effect Compensates torque Implant placed 1.5mm bucal and lingual from centre line to achieve Tripodism. www.indiandentalacademy.com
  35. 35. Weinberg 1996 In maxilla, lingual offset - increased 24% torque Buccal offset - Decrease 24% torque Maxilla - Tripod –increase in 24% torque Mandibular - Tripodism Maxilla - As far as bucally www.indiandentalacademy.com
  36. 36. Weinberg, 1996 In posterior working side, occlusion. Produces buccally inclined resultant line of force on maxilla and lingually inclined resultant line of force on mandible. Reduces 73% of torque in mandible www.indiandentalacademy.com
  37. 37. THERAPEUTIC BIOMECHANICS  Decrease cuspal inclination It reduces the distance between implant and resultant line of force. www.indiandentalacademy.com
  38. 38.  Cross occlusion Buccolingual relation  cross occlusion Reduces horizontal implant offset Reduces torque www.indiandentalacademy.com
  39. 39.  Implant Position Implant head as close to center line of restoration – Reduces horizontal offset. www.indiandentalacademy.com
  40. 40. PHYSIOLOGIC VARIATION – CENTRIC RELATION Kantor, Calagna, Calenza, 1973. Centric relation record show physiologic variation of ± 0.4mm Weinberg 1998 Occlusal anatomy modified to 1.5mm horizontal fossa Produce vertical resultant line of force within expected range of physiologic variation. www.indiandentalacademy.com
  41. 41.  Anterior Vertical Overlap Steep vertical overlap Extreme Torque www.indiandentalacademy.com Less steep Less Torque
  42. 42. BIOMECHANICS AND RESORPTION PATTERN Posterior Mandible Bone resorbs along root inclination Therefore, posterior mandible – bone resorb lingually Reactively Biomechancis Lingual position of restoration + Buccal implant placement - increased torque www.indiandentalacademy.com
  43. 43.  Therapeutically Can be done by  Reduced cusp inclination  Implant head close to centre line of restoration  Angulated abutment - parallelism www.indiandentalacademy.com
  44. 44.  Posterior Maxilla Reactively  Restricted maxilla  Location of sinus  Buccal cortical plate fracture  Unfavourable biomechanics www.indiandentalacademy.com
  45. 45. Therapeutically  Cuspal inclination – reduce  Head of implant close to center of restoration  Angled / custom – reangulated abutment  Cross occlusion  1.5mm horizontal fossa. www.indiandentalacademy.com
  46. 46. Anterior Maxilla Reactively Esthetically - Labially Proclined - Steep vertical overlap www.indiandentalacademy.com
  47. 47. Therapeutically  Lingual horizontal stop – redirect the force as vertically as possible.  Angled abutment  Implant head close to center of restoration www.indiandentalacademy.com
  48. 48. COMPLETE EDENTULISM AND BIOMECHANICS  Screw loosening not common these patients Implant placed across and around arch Cross splinting Lateral forces –Vertical force Tripodism Excellent resistance to bending www.indiandentalacademy.com
  49. 49. WIDER IMPLANTS Developed by Dr.Burton Langer Advantages  Increase in surface area  Limited bone height  Upon removal of failed standard size implant  Wider implant - Abutment screw 2.5m m Larger size – tighter joint – overall strength increases www.indiandentalacademy.com
  50. 50. BONE DENSITY AND BIOMECHANICS Density ∞ Strength ∞ Amount of contact with implant ∞ Distribution and dissipation of force Misch 1995  FEM study – stress contour is different for each bone density. With same load D1 - Crestal stress and lesser magnitude D2 - Greater crestal stress and along implant body D4 - Greatest stress and farther apically www.indiandentalacademy.com
  51. 51. BONE DENSITY AND TREATMENT PLAN MODIFIER  Prosthetic factors  Implant number  Implant – Macrogeometry  Implant – Design  Coating  Progressive loading www.indiandentalacademy.com
  52. 52. PROSTHETIC FACTOR As density decreases, biomechanical load should also decreased  Shortened cantilever length  Narrow oclusal table  Offset load minimized  RP4 > FP1, FP2, FP3, removal at night  RP5 – force shared by soft tissue  Force directed along long axis of implant www.indiandentalacademy.com
  53. 53. Implant Number Increase in number  Increase in functional loading area Implant Macrogeometry Length  D1 - 10mm  D2 - 12mm  D3 - 14mm with V-shaped thread screw Density decreased  Length increased www.indiandentalacademy.com
  54. 54. Width  Increase in width – increase in surface area  1mm increases  30% increase in surface area  D3 & D4  wider implants Implant Design  Smooth cylindrical implant – shear force at Interface – Coating with HA / Titanium  Titanium alloy (Ti-6Al-4V) exhibit best biomechanical, biocompatible, corrosion resistance. Coating  Increased bone contact area  Increased surface area www.indiandentalacademy.com
  55. 55. Progressive Loading Misch 1990 Gradual increase in occlusal load separated by a time interval to allow bone to accommodate. Softer the bone  increase in progressive loading period. Protocol Includes,  Time  Diet  Occlusal Contacts  Prosthesis Design www.indiandentalacademy.com
  56. 56. Time Two surgical appointments between initial placement and stage II uncovery may vary on density.  D1 - 5 Months  D2 - 4 Months  D3 - 6 Months  D4 - 8 Months Diet  Limited to soft diet – 10 pounds  Initial delivery of final prosthesis-21 pounds www.indiandentalacademy.com implant
  57. 57. Occlusal Material Initial step – no occlusal material placed over implant Provisional – Acrylic – lower impact force Final - Metal / Porcelain Occlusion  Initial - No oclusal contact  Provisional - Out of occlusion  Final - At occlusion www.indiandentalacademy.com
  58. 58. Prosthesis Design First transititional – No occlusal contact No cantilever Second transititional - Occlusal contact with no cantilever Final restoration - Fine occlusal table and cantilever www.indiandentalacademy.com
  59. 59. SINGLE TOOTH IMPLANT AND BIOMECHANICS  Requires good bone support  Control of occlusal lever parallel to long axis  Access for oral hygiene www.indiandentalacademy.com
  60. 60. When space exceeds 12mm When space less than 12mm www.indiandentalacademy.com
  61. 61. When space exceeds 8mm with limited width Should not be placed off center www.indiandentalacademy.com
  62. 62. Posterior Triangular Zone  Active zone  Occlusal loading parallel to long axis www.indiandentalacademy.com
  63. 63. Cantilever Prosthesis and Biomechanics  It result in greater torque with distal abutment as fulcrum.  May be compared with Class I lever arm.  May extend anterior than posterior to reduce the amount of force It depends on stress factors  Parafunction  Crown height  Impact width  Implant Number www.indiandentalacademy.com
  64. 64. Arch form English 1993 – AP Spread  Cantilever length = AP spread x 2.5  Tapering - canine and posterior implants with anterior cantilever  Square - Anterior implant with posterior cantilever www.indiandentalacademy.com
  65. 65. Tapering  Ovoid  Square Less dense bone  Anterior cantilever with prosthesis  Distal implants, placed to increase AP-spread. Maxilla - more implants required than mandible www.indiandentalacademy.com
  66. 66. CANTILEVER FIXED PARTIAL DENTURE  Sufficient bone height exist to place long implant, Avoid contact on central incisors during protrusion, labial excursion and maximum intercuspation  www.indiandentalacademy.com
  67. 67.  Group function - lateral movement  Avoid loading on canine  Lateral guidance provided by central and lateral incisor www.indiandentalacademy.com
  68. 68. Two implant supporting a first molar and 2nd premolar with 1st premolar cantilever  Active cusp eliminated  canine palatal structures. www.indiandentalacademy.com
  69. 69. Three implants placed with Two implants  risky 2nd premolar as cantilever and /or contraindicated www.indiandentalacademy.com
  70. 70. MANDIBULAR FLEXURE Picton 1962 Stated that mandibular move towards midline on opening  Because of external pterygoid muscle on ramus of mandible  Medial movement occur distal to mental foramen and increases as it approaches ramus.  James 1980 & Burch 1982  Movement - 0.8mm - 1st molar 1.5mm - Ramus area www.indiandentalacademy.com
  71. 71. FLEXION Implant - 0.1mm Natural teeth - 0.5mm mandible 10 to 20 times Complete cross arch splinting of posterior molar  Mandible flexion  Lateral force  Bone loss around implant  Loss of implant fixation  Material fracture  Unretained restoration  Discomfort on openings www.indiandentalacademy.com
  72. 72. www.indiandentalacademy.com
  73. 73. FATIGUE FAILURE  Characterised by dynamic cyclic loadind  Depends on – biomaterial geometry force magnitude number of cycles www.indiandentalacademy.com
  74. 74. Biomaterial  Stress level below which an implant biomaterial can be loaded indefinitely is referred as endurance limit. Ti alloy exhibits high endurance limit Number of cycles Loading cycles should be reduced To eliminate parafunctional habit To reduce occlusal contacts www.indiandentalacademy.com
  75. 75. Implant geometry  Resist bending & torsional load  Related to metal thickness  2 times thicker – 16 times stronger Force magnitude Arch position( higher in posterior & anterior) Eliminate torque Increase in surface area www.indiandentalacademy.com
  76. 76. IMPLANT DESIGN & BIOMECHANICS   Ti alloy offers best biomechanical strength & biocompatability Bending fracture resistance factor Wall thickness = (outer radius)4_ (inner radius)4  If outer diameter increases by 1mm & inner diameter unchanged 33% increase in bending fracture resistance  If inner diameter decreases by 1mm & outer diameter unchanged 20% increase in bending fracture resistance www.indiandentalacademy.com
  77. 77. www.indiandentalacademy.com
  78. 78. Thread pitch Thread depth www.indiandentalacademy.com
  79. 79. Depth –distance between major & minor diameter of thread www.indiandentalacademy.com
  80. 80. Implant macrogeometry Smooth sided cylindrical implants – subjected to shear forces Smooth sided tapered implants – places compressive load at interface Greater the taper – greater the compressive load delivery  Taper cannot be greater than 30 degree Implant width Increase in implant width – increases functional surface area of implant Increase in 1mm width – increase in 33% of functional surface area www.indiandentalacademy.com
  81. 81. Implant length Increase in length –Bicortical stabilisation Maximum stress generated by lateral load can be dissipated by Implants in the range of 10-15mm Softer the bone –greater length or width Sinus grafting & nerve re-posititioning to place greater implant length Resistance to lateral loading www.indiandentalacademy.com
  82. 82. Crestal module design Smooth parallel sided crest –shear stess Angled crest module less than 20 degree-Increase in bone contact area -Beneficial compressive load Larger diameter than outer thread diameter -Prevents bacterial ingress -Initial stability www.indiandentalacademy.com -Increase in surface area
  83. 83. Larger diameter & angulated crestal module design www.indiandentalacademy.com
  84. 84. Surface Coating -Titanium plasma spray -Hydoxyapatite coating Advantages -Increase in surface area -Roughness for initial stability -Stronger bone – implant interface Disadvantages -Flaking and scaling upon insertion -Plaque retention -Nidus for infection -Increased cost www.indiandentalacademy.com
  85. 85. IMPLANT PROTECTED OCCLUSION  Occlusal load transferred within physiologic limit  Misch,1993 width of occlusal table directly related to implant width  Narrow occlusal table with reduced buccal contour permits sulcular oral hygiene  Restoring occlusal anatomy of natural tooth -offset load -complicated home care www.indiandentalacademy.com
  86. 86. Posterior crest of maxilla medial to Mandibular crest Narrow occlusal table + reduced Buccal contour permits oral hygiene, Axial loading & reduces fracture www.indiandentalacademy.com
  87. 87. Apical Design Round cross-section do not resist torsional load Incorporation of anti –rotational feature -Vent hole- bone grow the hole -resist torsion -Flat sidegroove - bone grow against -places bone in compression www.indiandentalacademy.com
  88. 88. Maxillary lingual cusp & contour reduced Reduce offset load from opposing natural tooth Mandibular buccal cusp - in width & height www.indiandentalacademy.com
  89. 89. www.indiandentalacademy.com
  90. 90. Occlusal material Porcelain,resin,gold Porcelain - esthetics, chewing efficiency Gold - Impact force,chewing efficiency,fracture resistance,wear,interarch space,accuracy Acrylic - Esthetics , impact force,static load www.indiandentalacademy.com
  91. 91. IMPLANT ORAL REHABILITATION Constitutes  Muscle relaxation Absence of articular inflammation Stable condylar position Creating organic occlusion Absence of pain in stomatognathic system www.indiandentalacademy.com
  92. 92. Organic occlusion components Correct vertical dimension Maximum intercuspation in centric relation Adequate incisal & condylar guidance Stable bilateral posterior occlusal relation in equilibrium with long axis of implant Absence of prematurities Absence of interferences in eccentric movements www.indiandentalacademy.com
  93. 93. Bruxism patients Education & informed consent to gain co-operation in eliminating parafunction Use of night guard - anterior guided disooclusion - posterior cantilever out of occlusion - soft night guard releived over implant Soft tissue supported prosthesis - soft tissue tend to early load the implant & hence relieved over it Removable partial denture over healing abutment - 6mm hole diameter through metal is prepared www.indiandentalacademy.com
  94. 94. Final prosthesis - narrow occlusal table - centric occlusal contact aligned parallel to long axis Important criteria - additional implant - greater diameter implant www.indiandentalacademy.com
  95. 95. CONCLUSION Biomechanics is one of the most important consideration affecting design of the framework for an implant bone prosthesis.It must be analysised during diagnosis & treatment planning as it may influence the decision making process which ultimately reflect on the longevity of implant supported prosthesis www.indiandentalacademy.com
  96. 96. Bibliography Implant & restorative dentistry- Martin Dunitz Atlas of tooth & implant supported prosthesis-Lawrence A. Weinberg Atlas of oral implantology- A.Norman Cranin Contemprorary implant dentistry – Carl Misch Branemark implant system- John Beumer ITI dental implants- Thomas G.Wilson Implant prosthodontics- Fredrickson Dental implants- Winkelmann Oral rehabilitation with implant supported prosthesis - Vincente www.indiandentalacademy.com
  97. 97. www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

×