ORAL SURG Implants Flashcards
what statement classes edentulism as a disability?
WHO 2001 “The International Classification of Functioning, Disability and Health
in the UK, how many adults are edentulous?
6%
in the UK, how many adults have had 1 tooth removed?
74%
in 2007, how many nerve injuries were caused by implants?
30%
what is an alloplastic material in the context of implants?
a foreign material i.e., metal or ceramic
what is a xenoplastic material?
animal material
what is a dental implant?
a prosthetic device of alloplastic material implanted into the oral tissues beneath the mucosa and/or periosteal layer, and/or within the bone to provide retention and support for a fixed or removable prosthesis
what are the indications (patient factors) for placing an implant?
to replace lost tooth/ teeth
well motivated compliant patient
well maintained dentition - free of caries + perio sound
systemically well
non-smoker
not immunocompromised
no bruxism/ parafunctional habits
no impaired wound healing
how long for must a patient be a non smoker prior to implant tx under the NHS?
3 months smoking free, including nicotine vapes
what is the incidence rate of smokers losing implants?
1 in 10
why must a patient not be immunocompromised for implant tx?
physiological stress of implant and poor wound healing
what is the generic criteria for age of patient selection for implants?
females >18
males >20
why is age a factor in patient selection for implants?
TMJ growth must be at maximum
what are the contraindications for patient selection for implants relating to medical health?
poorly controlled diabetes (HBA1c >8)
bisphosphonate tx
psychiatric and mental health issues
blood disorders
immunodeficiency
alcohol/ drug use
bone disorders
epilepsy
tobacco use
poor dental health
why is mental health a contraindication for implants?
non compliant with attendance and aftercare
who can get implants on the NHS?
- congenital conditions: hypodontia/ malformed teeth
- trauma
- surgical interventions i.e. H+N cancer, pathology removal
- congenital extra oral defects i.e., eyes/ears
- repeated denture tx unsuccessful (edentulous in one jaw/ both)
- severe oral mucosal disorders i.e., xerostomia
- no suitable teeth for anchorage for ortho
what are the 3 parts to an implant system?
implant post
abutment
crown
what are names of types of implants?
straumann (used in tayside)
nobel biocare
Dentsply sirona
what are the requirements of an implant?
safety
compatibility (biological, biomechanical, morphological)
MRI safety and image compatibility
what makes an implant MRI safe?
not magnetised
describe osseointegration?
a direct structural and functional connection between ordered living bone and the surface of a load-carrying implant
what happens if too much force is transmitted to bone?
osteoclastic resorption
in what direction must forces be put on the bone supporting an implant?
axial
*bone does not like rotary/ tilted transmission of forces
what are host factors affecting osseointegration of implants?
bone density - withstanding stresses
bone volume and bone implant surface area
parafunctional habits
what are implant factors affecting osseointegration of implants?
implant micro design
chemical composition and biocompatibility
surface tx and coatings
implant tilting, prosthetic passive fit, cantilever, crown height, occlusal table, loading time
what type of force may a cantilever design impose on an implant?
tortional force
what is a good crown to root ratio?
1/3 crown to 2/3 root
describe the apposition onto the implant surface?
direct bone apposition onto the surface of the titanium without an intervening connective tissue layer
= no PDL for shock absorption
what are techniques used to roughen the surface of an implant?
titanium plasma spaying
grit blasting
acid etching
anodiation
calcium phosphate coating
what are the advantages of surface modification of implants?
greater amounts of bone-to-implant contact
more rapid integration with bone tissue
higher removal of torque values
what are the 2 metals used in implantology which do not inhibit the growth of osteoblasts?
titanium
zirconium
what can be used to resolve insufficient amount of bone for implant placement?
sinus lift/ grafting
what material can be used for a sinus graft?
bone from the patient and a xenograft (for stabilising)
when can implant be places following a sinus graft?
straight away or leave for 6 months for healing
what are the types of titanium used for implants?
commercially pure titanium (old)
titanium-6-aluminium-4-vanadium (Ti alloy)
roxolid (now used)
pure ceramics (also now used)
what are the advantages of using a Ti alloy for implant?
very high mechanical strength
better fracture resistance
increased resistance to corrosion
reduces heat transmission from implant to bone
in an implant assessment, what are the patient related factors?
oral hygiene
compliance
in an implant assessment, what are the medical factors?
medical fitness
medication
radiation tx
growth
in an implant assessment, what are the site related factors?
periodontal status
access
pathology near implant site
previous surgeries at the site
in an implant assessment, what are the surgical complexity factors assessed?
timing of implant placement
simultaneous or staged grafting procedures
number of implants
what are the timing options of implant placement?
immediate: 6-8 weeks post xla
delayed immediate: >12 weeks post xla
what is assessed of the bone prior to implant placement?
bone volume horizontally and vertically
what is assessed of soft tissue prior to implant placement?
keratinised mucosa
soft tissue quality/ thickness/ biotype
what is assessed of the site for implant placement?
proximity to vital anatomical structures
maxillary sinus
inferior alveolar canal and mental foramen
what is assessed in the adjacent teeth to an implant site?
papillae
recession
IP attachment
what is assessed during the aesthetic risk assessment prior to implant placement?
facial support
labial support
upper lip length
buccal corridor
smile line
maxillomandibular relationship
what is the importance of keratinised mucosa for implants?
an absence of an adequate amount of keratinised mucosa in dental implants is associated with higher plaque accumulation and gingival inflammation - this is because it cant withstand mechanical forces of toothbrushing
increased amount of keratinised mucosa is associated with less alveolar bone loss and improved indices of soft tissue health
what does bone quality impact?
primary stability
what is class I bone quality?
found in the anterior part of mandible
exclusively cortical dense bone
very little trabecular
what is class II bone density?
high density spongy bone surrounded by thick cortical bone
what is type III bone quality?
high density spongy bone surrounded by thin cortical bone
what is type IV bone quality?
low density spongy bone surrounding by thin cortical bone
what classes of bone quality give good primary stability?
class I and II
what may you do in the instance of class IV quality bone?
wait 12 weeks before restoring implant as it takes longer to achieve good stability
what will you take photographs of prior to implant placement?
document resting lip line and smiling lip line
position of midlines
and occlusion
what type of radiographs are taken for implant placement?
DPT - to visualise antrum, IDC, and bone height
CBCT - radiographic stent to mark position for implants
planning software - for location and angulation
what does the “safety zone” take into account ?
the coronal aspect of the mental foramen is 2mm above the inferior alveolar/ mental nerve
what is the minimum distance required from the implant shoulder to the adjacent tooth at bone level (mesial and distal)?
1.5mm
what is the minimum distance required between 2 adjacent implant shoulders?
3mm
what is the minimum distance required between the centres of 2 adjacent implants?
7mm
when would you want to recontour bone for implant placement?
knife edge ridges
mandibular tori
undercuts
what may you do if there is a lack of large bone volume ?
onlay grafts
inter positional grafts
PRF sticky bone
sinus lift
why is a knife edge ridge not ideal for implant?
need a flat surface
what are the 2 types of implants?
tissue level
bone level
what is a tissue level implant?
the implant has a highly polished transmucosal collar which is visible above the mucosa
*used under dentures
what is a bone level implant?
fully flush with the alveolus
how many stages are required for tissue level implants?
1 stage
how many stages are required for bone level implants?
2 stages
what is the most common design of implant?
parallel sided with apical taper
what is finite element analysis (FEV)?
transfer of load to surrounding bone tested by a mathematical model analysis
to avoid stress of the bone around the neck of the implant leading to bone loss
what is implant design affected by?
implant body shape
implant collar shape
threads - shape, pitch, height
grooves
what are the components of a roxolid implant material?
15% zirconium
85% titanium
what are features of a roxolid implant?
higher tensile strength than titanium
preserves bone
greater flex with small implants
what type of ceramic can be used for implants?
high performance zirconia ceramic (Y-TZP)
what are features of pure ceramic implants?
higher fatigue strength than grade 4 titanium implants
excellent clinical performance with 97.5% survival and success rates after 3 years
how many newtons vertical force can implants in the molar region maintain?
380-880N
how many newtons of vertical forces can implants in incisor region withstand?
<220N
how many newtons can implants withstand from lateral/shearing forces?
20N
list biological factors which may lead to implant failure?
overloading
bone not sufficient quality/ quantity
poor vasculature to the bone
list mechanical factors that may contribute to implant failure?
breakage of abutments
breakage of implant
breakage of screws
what are the timings of implant surgery?
immediate
immediate delayed
delayed
elective
when would you perform immediate implant surgery?
where there is good quality and volume of bone
what is the timeframe for delayed implant placement?
3-4 months for partial bone healing
what is the timeframe for elective implant surgery? and when would you perform this?
> 4 months for full bone healing
for edentulous arches (clearance)
list the drills involved in implant placement
round bur
pilot drills
twist drill
profile drill (coronal flare)
why doe blood move up the implant if it comes in contact?
the implant is hydrophillic
when would you use the depth gauge?
after drilled 6mm
what is the circular button on the depth gauge for?
it is the actual size of the implant so allows you to check how close you are to the adjacent teeth before drilling to the full depth and width
what is used to insert the implant?
a torque wrench with apical pressure
after tissue level implant insertion, what is left and for how long?
the implant remains exposed with a healing abutment for 2-3 months before the restorative team commence tx
after bone level implant insertion, what is left and for how long?
it is a 2 stage surgery so 2 months after implant insertion the implant is exposed and a taller healing abutment placed
why may dark triangles form around implants?
it is so hard to recreate papilla
why may mucosa look grey at the apex of a tooth?
an apicectomy has been carried out with amalgam
what are implant complications?
wound breakdown
infection
early loss
mucositis
peri implantitis
why may wound breakdown occur after implant surgery?
over tightened sutures which creates post op oedema and tissue necrosis
what can help prevent infection post implant surgery?
antiseptic mouthwash
some evidence of 2g pre op amoxicillin
why may there be early loss of implants?
over heating of the bone
very uncommon
why may mucositis occur after implant surgery?
poor OH
lack of keratinised mucosa
what is the issue caused by peri implantitis?
hard to control as the surface of implant isnt smooth and harbours bacteria
what are instruments for cleaning implants made of?
plastic
according to Buser et al what is success?
- absence of clinically detectable implant mobility
- absence of pain or any subjective sensation
- absence of recurrent peri-implant infection
- absence of continuous radiolucency around the implant at 12 week time point
what is the 8 year cumulative survival and success rates of non submerged implants?
96.7% survival
93.3% success
according to derek richards, what is the 10 year survival rate of implants?
96.4%
what does early failure mean?
it has not osseointegrated
it is lost
it is mobile
greater than 1mm bone loss in 1 year
greater than 0.2mm bone loss a year after
what is wound dehiscence?
the wound opens up a little after suture removal -a yellow slough forms which is just fibrin
how to solve wound dehiscence?
topical chlorhexidine gel 2 times a day
