Biology & Biomechanics of dental Implants Flashcards

1
Q

How is bone classified?

A
  • Compact/Cortical
  • Trabecular/Cancellous
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2
Q

Compact Bone

A
  • Aka Cortical Bone
  • Dense & strong
  • Give implant primary stability
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3
Q

Trabecular Bone

A
  • Aka Cancellous Bone
  • Fibrous Looking
  • Provides blood flow & healing
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4
Q

What are the different types of bone? How do they differ?

A
  • Types:
    • Lamellar bone
    • Woven Bone
    • Bundle Bone
  • Different
    • arrangement ofcollagen fibril
    • Mineral content
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5
Q

Woven Bone

A
  • Disorganized form during healing
    • Highly cellular
    • Low Mineral content
    • More pliable than mature lamellar bone
  • Formed by osteoprogenitor cells near blood vessels
    • during prenatal development, growth, healing
  • can stabilize an unloaded implant
    • can’t handle functional loading (weak)
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6
Q

Lamellar Bone

A
  • Primary Load-bearing tissue
  • Main component of mature cortical and trabecular bone
  • Highly organized
    • orientation of collagen fibrils: 1 direction
      • differ from one layer to another
  • Dense Mineralized matrix
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7
Q

Bundle Bone

A
  • Lines Socket
  • directly connected to tooth structure (Sharpey’s fibers)
  • first to degrade after extraction
  • Next to PDL of physiologically drifting teeth
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8
Q

Bone Density Classification:

  • Description
  • Tactile Analog
  • Typical Anatomical Location
A
  • affects initial stability of implant → osseointegration
  • D1 (most dense)
    • Dense cortical bone
      • marrow spaces barely visible
    • anterior mandible
    • very difficult to drill
  • D2
    • Thick porous cortical bone
      • coarse trabecular bone
    • anterior & posterior Mandible
      • anterior Maxilla
  • D3
    • Thin porous cortical bone
      • fine trabecular bone
    • Anterior & posterior maxilla
      • Posterior Mandible
  • D4 (least dense)
    • fine trabecular bone (primarily)
      • very thin cortical bone
    • posterior maxilla
    • Big marrow spaces
      • poor initial stability of implant
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9
Q

Bone Volume Classification

A
  1. Compact Cortical
  2. Thick cortical surrounds highly trabecular bone
  3. Thin cortical surrounds highly trabecular bone
  4. Thin Cortical bone and spongy core
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10
Q

Define: Osseointegration

A
  • direct connection b/w ordered, living bone & surface of load-carrying implant
    • structural & functional
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11
Q

Define: Fibre-osseous integration

A
  • Presence of CT b/w implant and bone
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12
Q

What are the different types of bone tissue response?

A
  • Distance osteogenesis
  • Contact osteogenesis
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13
Q

Distance osteogenesis

A
  • bone healing moves toward the implant
    • from edge of osteotomy to the implant
  • bone does not grow directly on implant
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14
Q

Contact Osteogenesis

A
  • Bone-guiding cells
    • migrate through clot matrix to implant surface
  • Bone forms quickly on implant surface
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15
Q

Implant: Healing Process

A
  • 2 Hours:
    • Socket filled w/coagulum from blood
    • Peripheral threads→Primary stability
  • Day 4:
    • Coagulum is exchanged for mesenchymal fibroblast cells
    • osteoclasts on bone surface
  • Week 1
    • Provisional matrix for woven bone & osteoblasts appear
    • new bone contacts implant surface
  • Week 2:
    • A lot of new bone around the implant
    • vascular structures appear
  • Week 4:
    • Lamellar bone appears
    • Central Bone is filled with primary spongiosa and vascular structures
  • Week 6:
    • 1° and 2° osteons are present in new bone
    • continued remodeling of lamellar bone
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16
Q

Osseointegration Factors

A
  • Implant biocompatibility
  • Design
  • Surface
  • Host Bed State
  • Surgical technique
  • Loading conditions
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17
Q

Implant Biocompatability: Osseointegration Factor

A
  • surface oxide properties
  • Titanium
    • Titanium alloy
  • Corrosion resistant
  • Load bearing capacity
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18
Q

Implant Design (Macrostructure)

A
  • Threaded vs cylinder
    • Threaded/screwed
      • 3 parameters:
        • Shape
        • Pitch (distance of full thread turn)
        • Depth (b/w root and crest of thread)
      • promote osseointegration
      • more functional for stress distribution
    • Cylindrical
      • press fit root form implants
      • depend on coating or surface condition for microscopic retention
  • Thickness
  • Platform Switching
    • smaller abutment on larger collar
    • helps move inflammation away from bone
  • Tissue vs bone level implant
    • tissue level implant
      • posterior region (non-esthetic)
      • large taper at top
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19
Q

Implant Surface

A
  • rough vs smooth
    • rough: more bone grown
      • greater bone to implant contact
  • Type of treatments:
    • turned/machined
    • sand blasted
    • acid etched
      *
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20
Q

Tooth vs Implant:

-Connection, Junctional epithelium, Connective Tissue, Biological Width, Vascularity, Probing depth, Bleeding of Probing

A
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21
Q

Tooth vs Implant

-diseased implants

A
  • Implants
    • high survival rate
    • superior option to replace teeth
    • biological and mechanical complications
  • Diseased implants
    • same treatment for natural teeth
      • not as successful
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22
Q

Implant Host tissues

A
  • Weaker Sulcular attachment→ ⇡BW → ⇡PD
    • implant PD: 4-5 mm
  • Ankylosis in bone
  • Circular & Parallel CT fibers
    • poor CT adhesion
  • No PDL
    • occlusal loads transferred directly to bone
      • Overload=Bone Loss
        • especially Lateral Forces
  • gingival Fibers:
    • parallel to long axis
    • do not attach
  • decreased vascularity→ Slower Healing
    • Unpredictable tissue regeneration
  • Less reliable BOP
    • Plaque/Bacteria→Greater Inflammatory Response→ More susceptible to tissue & bone loss
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23
Q

Implants: Vertical Height from the Occlusal Surface to the Crest

A
  • ⇡Crown Height= ⇡stress on alveolar crest= Lever Arm
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24
Q

Implant Diameter

A
  • Wider Diameter → ⇡ surface area of bone to implant contact → ⇡ stress distribution → ⇣MD and BL cantilever
  • Narrower implants in high stress areas
    • Mechanical implant failure or implant fracture
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25
Q

Splinting Implants vs teeth

A
  • Implants:
    • Improves stress distribution
    • Indication
      • high occlusal load areas
    • More difficult:
      • oral hygiene
      • make a passively fitting prosthesis
    • No PDL; osseointegrated
  • Teeth
    • PDL
      • allows vertical & horizontal movement
  • Splinting implants to teeth
    • increases stress at the neck of implant
    • Crestal bone loss
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26
Q

Factors causing marginal bone loss around implants

A
  • Infectious process
  • excessive loading conditions
  • Location, shape, and size of the implant-abutment micro gap and its microbial contamination
  • Biologic width geometry
  • implant surface roughness
  • Peri-implant inflammatory infiltrate
  • Micro-movement of implant and prosthetic components
  • repeating screwing & unscrewing
  • Traumatic surgical technique
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27
Q

Platform Switching

A
  • use smaller abutment on larger collar
    • inflammation moves away from bone
  • promotes Bone remodeling
  • if no platform switching= 1-2 mm bone loss
28
Q

Implant Success Criteria

A
  • A & Zarb
    • immobile implant
    • no evidence of peri-implant radiolucency
    • Mean vertical bone loss < 0.2 mm after 1 year
    • no pain, discomfort, infection, neuropathy, parasthesia, violation of mandibular canal or sinus drainage\
  • S & Zarb
    • Implant design allows satisfactory restoration
      • to dentist & patient,
29
Q

Implant: Causes of Failure

A
  • Mechanical
    • screw loosening/fracture
    • cement failure
    • framework fracture
  • Biologic
    • loss of osseointegration
    • sensory disturbances
    • peri-implant mucositis
  • Biological
    • patient related (medical history)
    • surgical reasons
    • Microbiological reasons
  • Biomechanical:
    • early loading
    • micro movement during healing
    • overloading
30
Q

Occlusal Forces on Implants

A
  • All applied to crystal bone (no PDL)
    • avg 0.1 mm lost/year to non-axial forces (lateral forces)
  • How to compensate:
    • Maxillary implants:
      • reduce palatal contour on crown
    • Mandibular Implants:
      • reduce buccal contour on crown
  • Flatter cusps are more ideal
    • evenly distribute forces
31
Q

When to use radiographs (PA, PAN, CBCT) during the implant process?

A
  • Initial Exam
    • PAN
  • Pre-op site exam
    • CBCT to observe residual alveolar ridge (RAR)
      • ID anatomy
  • Post-op:
    • PA if no problems
    • CBCT if problems
  • When to use CBCT:
    • Bone augmentation for implant placement
    • Mobile implant
    • Implant retrieval
32
Q

What are the different types of dental implants?

A
  • Subperiosteal
  • Transosteal
  • Endosteal
33
Q

Subperiosteal Implants

A
  • 1940s
  • metal framework
    • on top of jawbone w/transmucosal posts
  • Needs flap reflection
34
Q

Transosteal Implants

A
  • Through Jaw
    • Place anterior to mental foramen
  • Extraoral approach
35
Q

Endosteal Implants

A
  • alloplastic material
    • inside residual ridge
    • prosth foundation
  • 3 forms:
    • Blade
    • Cylinder (Aka press fit)
    • screw (Aka Threaded)
36
Q

Root Form Dental Implants

A
  • Type of endosteal implants
    • use vertical column of bone (like root of tooth)
  • most common design
  • Implant body & abutment placed separate
37
Q

Label 1-4 on picture

A
  1. Definitive Prosthesis
  2. Retaining screw→ connects abutment to implant body
  3. Abutment→ connects implant body to definitive prosthesis
  4. Implant Body
38
Q

What are the different parts of the implant body?

A
  • Platform
  • Body
  • Apex
  • Inner Threading
39
Q

What are the different platforms that can be used on an implant body?

A
  • External Platform
  • Morse Taper
  • Internal Platform
40
Q

What is this?

A

External Platform (implant body)

41
Q

What is this?

A

Internal Platform

42
Q

What is this?

A

More Taper (Platform)

43
Q

What is this?

A

Blade Implants (type of endosteal implant)

44
Q

What is this?

A

Cylinder or Press Fit Implant

(Endosteal implant)

45
Q

What is this?

A

Blade Implant

(type of endosteal implant)

46
Q

What is this?

A

Screw/Threaded Implants

(type of endosteal implant)

47
Q

Implant: Indications vs Contraindications

A
  • Indications:
    • can’t wear a removable or complete denture
    • need for long-span fixed prosthesis w/questionable prognosis
    • unfavorable number & location of tooth abutments
    • Single tooth loss that requires prep of minimal or non-restored teeth for fixed prosthesis
  • Contraindications:
    • Acute or terminal Illness
    • Uncontrolled metabolic disease (a1c>7.5)
    • Radiation therapy
    • Bisphosphonates or bone sparing agents (prolia)
    • Unrealistic patient expectations
    • Operator lack experience
    • lack of vertical space
    • can’t restore w/prosthesis
48
Q

The increase need and use of implant treatment result from what factors?

A
  • older population living longer
  • tooth loss due to age
  • Fixed prosthesis failure
  • anatomical consequences of edentulism
  • poor performance of removable prosthesis
  • psychy of tooth loss
    • needs & desires of baby boomers
  • Implant supported prostheses:
    • predictable
    • long term
    • increased public awareness
    • advantages of implant supported restorations
49
Q

Single Tooth Replacement: Implant vs FPD

A
  • FPD:
    • avg life span= 10 years (50% survival)
    • caries=most common cause of failure
    • Abutment teeth
      • 15% require endo
      • Failure rate:
        • 8-12% at 10 years
        • 30% at 15 years
  • Implant: (advantages)
    • High success rate (>97% at 10 years)
    • Adjacent teeth Decreased risk of:
      • caries
      • endo problems
      • abutment tooth loss
      • cold or contact sensitivity
    • Improved:
      • edentulous bone maintenance
      • esthetics of adjacent teeth
      • easier to clean proximal surfaces of adjacent teeth
    • Psychological advantage
50
Q

Anatomical Consequences of Edentulism

A
  • Close relationship b/w tooth and alveolar process continues throughout life
    • Wolffs Law
      • bone remodels due to forces applied
      • Modified bone function→ change in internal architecture and external configuration
      • Tooth is lost→ No stimulation of bone→ ⇣ Trabeculae & bone density in the area
        • Lose Bone Volume: Width→Height
  • Complete or Partial Denture (removable)
    • does not stimulate or maintain bone
    • accelerates bone loss
      • greater rate in poor fitting denture
51
Q

Consequences of Bone loss in Fully Edentulous Patients

A
  • Forward movement of prosthesis due to anatomical inclination
    • angulation of mandible w/moderate to advanced bone loss
  • Thin mucosa, w/sensitivity to abrasion
  • Lose
    • basal bone
    • anterior ridge & nasal spine:
      • causes increased denture movement & sore spots
  • Parasthesia from mandibular neuromuscular canal
  • More active role of tongue in mastication
  • esthetic appearance of lower ⅓ of face
  • Increased risk of mandibular body fracture
52
Q

Soft Tissue consequences of edentulism

A
  • Lose attached, keratinized gingiva as bone is lost
  • Unattached mucosa for denture support→ sore spots
  • Tissue thickness decreases w/age
    • systemic diseases causes more sore spots for dentures
  • Tongue:
    • Increases in size→ decreases denture stability
    • more active role in mastication→”. “
  • Decreased neuromuscular control of jaw in elderly
53
Q

Esthetic Consequences of Edentulism

A
  • Decreased
    • facial height
    • horizontal labial angle of lip
  • Increased:
    • Columella philtrum angle
    • maxillary lip length
  • Loss of:
    • labiodental angle
    • muscle tone in facial expresión m.
  • Thinning of:
    • vermillion border of lips
  • Deepening of:
    • nasolabial groove
    • vertical lines in lip and face
  • Ptosis of:
    • buccinator muscle attachment→jowls at side of face
    • mentalis muscle attachment
  • Chin rotates forward→ Prognathic appearance
54
Q

Decreased performance of complete denture

A
  • Decreased:
    • Bite Force: 200-50 psi
      • 15 years= 6 psi
    • Masticator efficiency
    • Life span
    • healthy food intake
      • limited food selection
  • More drugs to tx GI disorders
55
Q

Decreased performance of removable partial dentures

A
  • Low survival rate
    • 4 years=60%
    • 10 years=35%
  • Abutment Teeth:
    • repaire rate:
      • 5 years= 60%
      • 10 years= 80%
    • Tooth Loss within 10 years= 44%
    • Increased:
      • mobility
      • plaque
      • BOP
      • caries
  • Increased Bone loss
56
Q

Advantages of implant supported prostheses:

A
  • Maintain:
    • Bone
    • Facial Esthetics (Muscle tone)
  • Improve:
    • esthetics (teeth positioned for appearance vs decreasing denture movement)
    • Phonetics
    • Occlusion
    • oral proprioception (Occlusal awareness)
    • masticatory performance
    • stability & retention of removable prosthesis
    • psych health
  • Increase:
    • prosthesis success
    • survival time of prosthesis
  • Decrease:
    • size of prosthesis (eliminate palate, flanges)
  • Restore &. maintain occlusal vertical dimension
  • No altering adjacent teeth
  • More permanent replacement
  • Provide fixed vs removable prosthesis
57
Q

Occlusal Force Distribution: Natural Teeth

Axial vs Lateral Forces

A
  • Axial Forces
    • Parallel to long axis
    • forces distributed along entire root surface
  • Lateral Forces (off axis)
    • not parallel to long axis
    • forces distributed to localized area
      • (not entire root surface)
    • Center of Rotation:
      • ½ to ⅓ root length apical to alveolar crest
      • Depends on alveolar bone height
    • High cusps have higher torque than low cusps
58
Q

Occlusal Force Distribution: Implants

A
  • Any direction or magnitude (axial or lateral)
    • forces/stress distributed at the crest of alveolar bone
      • Crestal Stress→Bone remodeling
        • avg annual bone loss= 0.1 mm
      • Crestal bone around implants= Fulcrum point
    • Axial Force
      • compressive forces on crestal bone
      • if force is within physiologic limits→ no bone loss
    • Non-Axial Force (lateral)
      • Shear forces to bone→Bone Loss
  • Cusps:
    • High cusps have higher torque than low cusps (Same as teeth)
    • Large cusp angles→ ⇡ contact surface area→ Shear Forces
      • A more Ideal Flat Cusp → concentrated forces over implant body → Reduce Shear Forces
  • Occlusal Table
    • Ideal Crown Contour= Diameter of implant body
      • reduced cusp height
    • Large Occlusal table→ Shear forces
    • Adjustments:
      • Maxillary Implant Contour
        • Palatal contour reduction
      • Mandibular
        • Buccal Contour reduction
59
Q

Occlusal Force Distribution: Factors affecting stress on implants

A
  • Occlusal Contact Location
  • Vertical height from the occlusal surface to the crest
  • implant diameter
  • Splinting of implant restorations
60
Q

Implants: Occlusal Contact Location

A
  • Over bulked/contoured implant crown create a cantilever
    • overload force→ crestal bone loss or component failure
    • buccolingual or mesiodistal dimension
61
Q

Periodontal Sulcus vs Peri-implant sulcus

A
  • Peri-implant sulcus
    • weaker sulcular attachment→ ⇡Biological Width→ ⇡ PD (sulcular depths)
      • Normal Physiologic PD > 4-5mm around implants
62
Q

Periodontal Attachment vs Peri-implant attachment

A
  • Teeth:
    • gingival fibers:
      • perpendicular to tooth long axis
      • attach to tooth surface
  • Implants:
    • Gingival fibers:
      • parallel to implants long axis
      • do not attach to implant surface
    • Poor CT adhesion
      • (vs natural teeth)
63
Q

Implants: Inflammatory Response

A
  • Bacteria/Plaque
    • Greater inflammatory response
      • more susceptible to tissue & bone loss
64
Q

Implants: Inflammatory Response

A
  • Implants:
    • Greater attachment breakdown with bacterial challenge
      • Implant seal breaksdown→ ⇡Tissue loss (vs teeth)
    • Greater inflammatory response to bacteria
      • more susceptible to tissue & bone loss when challenged by plaque
65
Q

Implants: Tissue Healing Response

A
  • Slower healing due to decreased vascularity
  • Unpredictable tissue regeneration
66
Q

Tooth root vs Implant Body

A
  • PDL= suspension system
    • transfers occlusal loads to bone
    • micro movements to dissipate overloads
  • Implants:
    • NO PDL
    • occlusal loads transferred directly to bone
      • Overload=Bone Loss
        • Lateral Forces
      • More technical complications
        • screw loosening
        • fracture