11 - Implant planning and placement

Question 1

Define osseointegration.

Answer 1

Direct functional and structural connection between load bearing dental implant and living (organised) bone

Question 2

What are the stages of osseointegration?

Answer 2

• primary, implant anchored in bone by friction between osteotomy and implant design features
• secondary, process of functional connection between bone and implant, living bone grows onto surface to heal and remodel into surface of bio-inert material

Question 3

Describe the healing after implant placement.

Answer 3

• blood clot forms around implant surface
• blood clot is reorganised into new bone
• bone matures in close proximity to implant surface design

Question 4

Compare the supra-crestal soft tissue of a tooth vs an implant.

Answer 4

Tooth
- more fibroblasts
- less collagen
- collagen fibres are orientated perpendicular to root surface (insert to root surface)

Implant
- less fibroblasts
- more collagen
- collagen fibres oriented parallel to implant crown (do not insert)

Question 5

Compare the sub-crestal tissue of a tooth vs an implant.

Answer 5

Tooth
- tooth anchored by visco-elastic periodontal complex (bone, PDL, cementum)
- capable of physiologic adaptation
- resilient tissue attachment

Implant
- implant anchored to bone with direct functional contact
- no physiological adaptation possible
- rigid connection (if occlusion incorrect, components or opposing teeth may fracture)
- no proprioception (problem in bruxism)

Question 6

What materials are commonly used for dental implants?

Answer 6

• titanium
• titanium zirconium
• ceramic implants (yittra stabilised zirconia)

Question 7

What is the concentration of Ti in implants?

Answer 7

> 85% to produce titanium dioxide layer

Question 8

What are the component percentages for Ti-Zr implants?

Answer 8

85% Ti
15% Zr

Question 9

What are the benefits of ceramic implants?

Answer 9

• non-metallic coloured so can be placed in thin tissue biotype or thin underlying bone with no shine through
• less technique sensitive

Question 10

What are the benefits of Ti-Zr implants?

Answer 10

• increased strength compared to Ti implants
• can reduce diameter of implant for narrower spaces

Question 11

What is the most commonly used length for implants?

Answer 11

• short
• 8-10mm

Question 12

What are the tissue types of implant design?

Answer 12

• bone level vs tissue level
• tapered vs parallel

Question 13

When are bone level implants indicated?

Answer 13

Aesthetic zone

Question 14

When are tissue level implants indicated?

Answer 14

Posterior region

Question 15

When are tapered implants indicated?

Answer 15

• provide increased primary stability
• root convergence apically

Question 16

What are the difference surfaces designs for implants?

Answer 16

• machined vs turned
• roughness (smooth, mild, moderate, rough)
• surface treatment (sandblasting, acid etch, plasma spray)

Question 17

How does the surface design influence the performance of the implant?

Answer 17

• rougher surfaces is better for retention
• rougher surface is more prone to peri-implantitis due to bacteria within the biofilm binding to implant

Question 18

What is the purpose of a dental implant?

Answer 18

• replace missing teeth (aesthetic, function)
• preservation of alveolar bone

Question 19

What what age are anterior implants suitable?

Answer 19

> 21

Question 20

What medications can impact the implant success?

Answer 20

• SSRIs
• PPIs
• bisphosphonates
• steroids

Question 21

What other medical history can impact implant success?

Answer 21

• radiotherapy
• poor controlled diabetes
• CV disease (increases success)

Question 22

How does smoking impact implants?

Answer 22

• increased risk of implant failure and peri-implantitis
• dose dependant, <10 = medium risk, >10 = high risk
• affects the vascularity, fibroblast and osteoblast function and neutrophils

Question 23

Define a high smile line.

Answer 23

• > 2mm soft tissue show
• do not place implants

Question 24

Define VME.

Answer 24

Vertical maxillary excess

Question 25

Define a medium smile line.

Answer 25

<2mm of soft tissue show

Question 26

Define a low smile line.

Answer 26

Lip covers >25% of teeth

Question 27

What are the different gingival phenotypes?

Answer 27

• thick flat
• thick, scalloped
• thin, scalloped

Question 28

How do you differentiate gingival phenotype?

Answer 28

Probe visibility through gingiva

Question 29

What is the ideal bone crest to contact point?

Answer 29

</= 5mm

Question 30

What is the impact of the bone crest to contact point?

Answer 30

• determines the gingival aesthetics
• if distance is too large, papilla will not be present

Question 31

How does infection at the implant site impact success?

Answer 31

• no infection is best
• chronic infection has little impact

Question 32

What is the relevant local anatomy when placing implants in the maxilla?

Answer 32

• maxillary sinus
• nasal floor
• nasopalatine canal
• infraorbital nerve

Question 33

What is the relevant local anatomy when placing implants in the mandible?

Answer 33

• inferior alveolar canal
• mental foramen
• incisive canal
• lingual perforation vessels
• submandibular fossa

Question 34

What is meant by prosthetically driven planning?

Answer 34

• implant placement is planned from the final planned prosthesis position
• ensures that implant is placed in correct orientation

Question 35

What is the safe margin from adjacent teeth for implant placement?

Answer 35

• 1.5mm
• lowers risk of damage to adjacent teeth and bone necrosis or soft tissue defects
• if 2 adjacent implants, double the biologic width

Question 36

What is the ideal buccal and palatal positioning of an implant?

Answer 36

• 1-2mm bone labially
• consider GBR if dehiscence, fenestration or inadequate contour

Question 37

What is the ideal apical/coronal positioning of an implant?

Answer 37

If bone level implants, most coronal part of implant should be 2mm from planned gingival margin

Question 38

What are the different placement protocols?

Answer 38

• immediate implant placement
• early implant placement with ST healing (4-6 weeks)
• early implant placement with partial bone healing (12-16 weeks)
• late implant placement in healed site (>6 months)

Question 39

What special investigations are required for implant placement?

Answer 39

• mounted study models
• diagnostic wax up
• surgical template
• essix (provisional)
• clinical photographs
• CBCT