11 - Implant planning and placement Flashcards
Define osseointegration.
Direct functional and structural connection between load bearing dental implant and living (organised) bone
What are the stages of osseointegration?
- 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
Describe the healing after implant placement.
- blood clot forms around implant surface
- blood clot is reorganised into new bone
- bone matures in close proximity to implant surface design
Compare the supra-crestal soft tissue of a tooth vs an implant.
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)
Compare the sub-crestal tissue of a tooth vs an implant.
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)
What materials are commonly used for dental implants?
- titanium
- titanium zirconium
- ceramic implants (yittra stabilised zirconia)
What is the concentration of Ti in implants?
> 85% to produce titanium dioxide layer
What are the component percentages for Ti-Zr implants?
85% Ti
15% Zr
What are the benefits of ceramic implants?
- non-metallic coloured so can be placed in thin tissue biotype or thin underlying bone with no shine through
- less technique sensitive
What are the benefits of Ti-Zr implants?
- increased strength compared to Ti implants
- can reduce diameter of implant for narrower spaces
What is the most commonly used length for implants?
- short
- 8-10mm
What are the tissue types of implant design?
- bone level vs tissue level
- tapered vs parallel
When are bone level implants indicated?
Aesthetic zone
When are tissue level implants indicated?
Posterior region
When are tapered implants indicated?
- provide increased primary stability
- root convergence apically
What are the difference surfaces designs for implants?
- machined vs turned
- roughness (smooth, mild, moderate, rough)
- surface treatment (sandblasting, acid etch, plasma spray)
How does the surface design influence the performance of the implant?
- rougher surfaces is better for retention
- rougher surface is more prone to peri-implantitis due to bacteria within the biofilm binding to implant
What is the purpose of a dental implant?
- replace missing teeth (aesthetic, function)
- preservation of alveolar bone
What what age are anterior implants suitable?
> 21
What medications can impact the implant success?
- SSRIs
- PPIs
- bisphosphonates
- steroids
What other medical history can impact implant success?
- radiotherapy
- poor controlled diabetes
- CV disease (increases success)
How does smoking impact implants?
- 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
Define a high smile line.
- > 2mm soft tissue show
- do not place implants
Define VME.
Vertical maxillary excess
Define a medium smile line.
<2mm of soft tissue show
Define a low smile line.
Lip covers >25% of teeth
What are the different gingival phenotypes?
- thick flat
- thick, scalloped
- thin, scalloped
How do you differentiate gingival phenotype?
Probe visibility through gingiva
What is the ideal bone crest to contact point?
</= 5mm
What is the impact of the bone crest to contact point?
- determines the gingival aesthetics
- if distance is too large, papilla will not be present
How does infection at the implant site impact success?
- no infection is best
- chronic infection has little impact
What is the relevant local anatomy when placing implants in the maxilla?
- maxillary sinus
- nasal floor
- nasopalatine canal
- infraorbital nerve
What is the relevant local anatomy when placing implants in the mandible?
- inferior alveolar canal
- mental foramen
- incisive canal
- lingual perforation vessels
- submandibular fossa
What is meant by prosthetically driven planning?
- implant placement is planned from the final planned prosthesis position
- ensures that implant is placed in correct orientation
What is the safe margin from adjacent teeth for implant placement?
- 1.5mm
- lowers risk of damage to adjacent teeth and bone necrosis or soft tissue defects
- if 2 adjacent implants, double the biologic width
What is the ideal buccal and palatal positioning of an implant?
- 1-2mm bone labially
- consider GBR if dehiscence, fenestration or inadequate contour
What is the ideal apical/coronal positioning of an implant?
If bone level implants, most coronal part of implant should be 2mm from planned gingival margin
What are the different placement protocols?
- 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)
What special investigations are required for implant placement?
- mounted study models
- diagnostic wax up
- surgical template
- essix (provisional)
- clinical photographs
- CBCT
