Implant Intro Flashcards
What are questions to ask when evaluating for implant placement
Bone Quantity good? Bone Qualit good? Soft tissue Quantity Soft tissue Quality Can it be placed now? Is prep work needed
Albrektsson Criteria for sucess
- No mobility
- No peri implant radiolucency
- vertical bone loss less than .2mm after first year
- absence of signs/symptoms of pain, paresthesia, infection, etc
Other criteria for implant sucess
- Oseointegration
- functional restoration
- acceptable esthetics
- long term tissue health
Prereqs to implant therapy
Med hx
Dent Hx
Oral health status
adequate soft tissues and bone
Diabetes and Implant success
-mixed results but most studies don’t look at control of diabetes
Oates 2014
No evidence of altered implant survival with elevated HbA1c, BUT looked only at edentulous patients
Osteoporosis and Implants
No difference between studied groups
-unless smoking involved then 2.6% increase in failure rate
2 types of drugs for osteoporosis
- Antiresorptive drugs
- Antiangiogenisis agents
Antiresorptive drugs
alter bone metabolism mainly by inhibiting osteoclast function; altered bone metabolism in patients with bone cancers
– Bisphosphonates
– RANK ligand inhibitor (denosumab) – (monoclonal antibody
to RANK ligand (RANK‐L)
Antiangiogenisis agents
Antiangiogenesis agents – interfere with new blood
vessel formation; used in patients with certain types of
tumors/cancers (sunitinib, sorafenib, bevacizumab,
sirolimus)
Bisphosphonates
– decrease osteoclastic activity
– Oral agents:
•Alendronate (Fosamax), Risedronate (Actonel), Ibandronate
(Boniva)
–IV agents:
•Pamidronate (Aredia); Zolendronate (Zometa)
– given IV once every few weeks or months (mainly for bone
malignancy or Paget’s disease; used in some severe osteoporosis
cases)
• Reclast
– Yearly IV infusion of zolendronate for osteoporosis
“Osteonecrosis of the jaw”
originally
identified in patients taking bisphosphonates
– seen after invasive procedure like flap surgery,
implant placement or tooth extraction; spontaneous
cases have frequently been reported (make up large
percentage of cases)
– signs of ONJ: jaw pain, exposed bone, tooth mobility,
numbness, bone sequestration (similar to
osteoradionecrosis)
Bisphosphonate mechanism
• Bisphosphonates bind to bone mineral with minimal
metabolism of the drug
• Drugs are internalized by osteoclasts, resulting in:
– inhibition of osteoclast recruitment
– inhibition of osteoclastic activity
– decreased osteoclast life span
• Drugs also inhibit endothelial cell function in bone:
– may impair blood supply to bone
Which has greater risk for causing MRONJ, oral or IV infusible
Infusible
Does risk of MRONJ decrease after discontinuation of drug
No
Stats for MRONJ risk of different drugs in cancer patients
•Risk of ONJ in cancer patients taking placebo in clinical
trials = 0 ‐ 0.019% (0‐1.9 cases per 10,000 patients)
•Risk of ONJ in cancer patients taking zolendronate =
0.7‐ 6.7% (70‐670 cases per 10,000 patients)
– 50‐350 times higher risk for IV zolendronate than placebo
•Risk of ONJ in cancer patients taking denosumab = 0.7‐
1.9% (70‐190 cases per 10,000 patients)
– risk close to zolendronate
•Risk of ONJ in cancer patients taking bevacizumab
(antiangiogenic agent) = 0.2% (20 cases per 10,000)
MRONJ stats of different drugs in patients with osteoporosis
•Risk of ONJ in large, long‐term studies of oral
bisphosphonates for osteoporosis was 0.1% (10 cases
per 10,000), which increased to 0.21 (21 cases per
10,000) among patients with greater than 4 years of
oral BP exposure
•Risk for ONJ among patients treated for osteoporosis
with either zolendronate annually (Reclast) or
denosumab semi‐annually (Prolia) (0.017 – 0.04%)
approximates the risk for ONJ of patients enrolled in
placebo groups (0%‐0.02%)
Take homes of MRONJ
•Risk of ONJ for drug regimens used to treat
osteoporosis is more than 100 times lower than risk
for drug regimens used to treat cancer
•Risk for ONJ does increase with time of use (for both
cancer regimens and osteoporosis regimens)
Dental guidelines for MRONJ at risk pos (IV)
IV agents: Procedures that involve direct osseous injury
should be avoided. Recommend no surgery (including ext)
in patients taking IV agents (do endo, coronectomy, etc,
rather than ext tooth); recommend no dental implants in
these patients.
• If patient is about to start IV agents, try to remove teeth with
poor prognosis ahead of time and make sure patient’s oral health
is good before drug initiation
2014
INFORMED CONSENT
MRONJ risk pt oral med Dental guidelines
-patients taking oral agents < 4 years and have no other”
“clinical risk factors (e.g., diabetes, corticosteroids, smoking, alcohol, poor OH, chemotherapy, etc.): no alteration in planned surgery. If implants are placed,”
“nformed consent concerning possible future implant failure.”
• Patients taking oral agents > 4 years with or without any
concomitant medical therapy (steroids/antiangiogenic
agents): contact prescribing physician to discuss
discontinuation of drug for 2 months prior to oral surgical
therapy and until after bony healing is complete (which
could be several months after tx)
MRONJ drug holiday
dictated by physician not dentist
What are some medications types that might alter surgical plan
– anticoagulants (Coumadin/warfarin)
–diabetes medications (e.g., insulin)
–CNS depressants, especially if conscious sedation is
to be used (antidepressants, antianxiety agents,
some antihistamines, others)
Radiation therapy impact on Implants
– Increases risk of implant failure (and complications such as
osteoradionecrosis)
– Failure rate dependent on total radiation dose
• 2.6% failure rate with <55Gy total radiation
• 10.1% failure rate with >55Gy total radiation
– Hyperbaric oxygen may decrease failure rate, but little direct
evidence
Smoking and Implant SURVIVAL
• Systematic review analyzed 14 articles with
implant survival data for smokers (12 to 144
months)
• Overall survival rate:
SMOKERS 89.7%
NONSMOKERS 93.3%
Pooled estimate of difference in overall survival rate was 2.7%
better for nonsmokers (p=0.0009). Statistically significant, but not
clinically impressive.
Smoking and Implant SUCCESS
• Analyzed 7 articles with implant success data for
smokers (12 to 48 months)
– Varying success criteria in articles
• Overall success rate:
SMOKERS 77.0%
NONSMOKERS 91.0%
Pooled estimate of difference in overall success rate was 11.3%
better for nonsmokers (p=0.005). Statistically significant, and
impressive clinical difference.
Smoking and Implant big pictures
– Smoking decreases implant survival, but mainly at
maxillary sites
– Smoking decreases implant success in both
maxillary and mandibular sites
– Impact of smoking is lower with use of microroughened
surfaces than for machined surfaces
Does oral health need to be controlled before implants
Yes
Periodontitis and survival
– Implant survival lower when subjects had more than
30% of teeth with bone loss >4mm (i.e., history of
periodontitis)
even if disease was currently under control!
Periodontitis and Perioimplantits
O.R. for peri‐implantitis was 4.7 in subjects with
>4mm bone loss at >30% of teeth compared to <30%
of teeth at time of implant placement
• % of subjects who developed peri‐implantitis requiring
surgery, and/or systemic or local antibiotics:
– Periodontally healthy = 10.7%
– Hx of treated moderate periodontitis = 27.0%
– Hx of treated severe periodontitis = 47.2%
Periodontits and roughened implants
Implant survival rates are slightly lower in patients with
past hx of periodontitis, but survival rates are generally
>90% with microroughened surfaces
Implant PD and periodontitis
– Periodontally healthy = 4.2mm
– Hx of treated moderate periodontitis = 5.1mm
– Hx of treated severe periodontitis = 5.5mm
• % of implants having 6mm PD at 1+ sites during maint:
– Periodontally healthy = 6.6%
– Hx of treated moderate periodontitis = 29.5%
– Hx of treated severe periodontitis = 45.6%
Why do you want adequate soft tissue
– to cover implant site – to ensure esthetic result – to allow long‐term maintenance of health
When is it best to treat soft/hard tissue defects
Prior or at implant placement
Why do you want adequate hard tissues
– to allow for implant placement – to ensure implant stability – to allow long‐term maintenance of health
What drives implant placement location
Where it needs to be restoratively not where tissues are adequate. If tissues can’t be augmented then implant shouldn’t be used
How is bone located
– palpation – bone sounding – radiographs • Incisions should always be placed over bone • Implant must be placed in bone or bone must be augmented Anatomical Considerations • Where is the bone?? – palpation •Least accurate technique •Can determine gross bony contours •Often overestimates/underestimates amount of bone truly present
Palpating Bone
•Least accurate technique •Can determine gross bony contours •Often overestimates/underestimates amount of bone truly present The time to find out how much bone you have is not the day of surgery
Bone sounding
• patient is anesthetized and probe is placed through soft tissue to bone • bone can be “mapped” and transferred to cast • Better to use template that covers entire F&L
Radiographic imaging of bone
•Very useful
•Can still under/overestimate actual bone
•Can choose between many types of
radiographs (2‐D and 3‐D)
– variations in magnification and image distortion
can be critical
•3‐D imaging is a huge plus for many patients; not as
important for others
Radiogrpahic magnification
Stats
• Periapical 7% • Panographic 22‐28% • Cross‐sectional view Linear tomography 10% Computed tomography 0%
Areas of anatomic concern for bone levels
Nasal floor Maxillary sinus Incisive canal Mental foramen Mandibular canal
Surgical Goal of diagnostic phase
Know where bone is before first incision is made
Bone resorption and implant placement
Severe resorption can affect ability to place implants and patient’s ability to maintain implants – Implant may violate mandibular canal, maxillary sinus, bony concavity – Implant may not be positioned at same angles as the natural tooth • As ridge resorbs, implant placement may violate confines of mandible or maxilla
What is minimum implant length
Historically 10 mm
-Meta‐analyses show that with rough surface
implants, survival rates are same for implants
<10mm as for implants >10mm
Where do stresses concentrate in implants
Coronal Aspects
Where is the bested worst density of bone for implant placement
Poorest-max posterior
Best - Man Ant
Minimum BL crest width and minimum amount of bone B and L of implant
> 7-8mm total with 2 mm buccal and 1.5 mm L
How much bone should be between PDL and implant
2mm
How much bone between implants
3mm
How far apically from gingival margin should the implant be placed
3.4 mm to maintain gingival height
2-3mm from CEJs of adjacent teeth
Platform switch and interplant distance
recent studies show that
implants having narrower abutment connection
(“platform switch) can be placed closer together
than 3mm and not lose inter‐implant bone (some
as close as 1.5‐2.0mm)
– Keep in mind heat generation and bone trauma
during osteotomy preparation on implants placed
close together
– Keep in mind emergence profile of final restorations
for implants placed close together
EMERGENCE PROFILE
• The manner in which the restoration
emerges through the soft tissue from its
base at the implant interface
Bone quality and Implant sucess
– Earlier studies suggested that implant survival & success
rates decreased in posterior areas of lesser bone quality
•This was primarily true with machined Ti surfaces
-roughened surfaces may not be as restricted
Things to avoid in maxilla
– Nasal cavity
– Maxillary sinus
– Nasopalatine canal/foramen; greater/lesser palatine
foramina
Things to avoid in mandible:
– Mandibular canal; mental foramen
– Lingual concavities/fossae (e.g., submandibular
salivary gland fossa, inferior to mylohyoid ridge)
• Perforation of lingual periosteum may have major negative
effects (bleeding, nerve trauma)
Maxillary sinus
– Lined by Schneiderian
membrane
– Pneumatization after early tooth
loss
Max Sinus Septae
• Can limit elevation of lateral window during sinus elevation • Increase risk of membrane tear • 13/41 (32%) maxillae with >1 septum • 2/41 (5%) with 2 septa • 73% in premolar region • 20% in first molar region
Incisive canal
• Nasopalatine nerve • Sphenopalatine artery – Remove contents – Bone graft – Only 4% would be in the way of an implant
Anterior loop of IA nerve
• 88% of 22 skulls • 76% bilateral • Length ranged from 1-11mm with mean 4.13 ± 2.04mm
Anterior Vasculature of Man
• Sublingual artery • Submental artery • Incisive artery • Median lingual foramen found 85- 99% • Inferior midline foramen found 76%
Lingual Artery
– Tongue, floor of mouth, lingual mucosa & gingiva – Can be damaged by lingual perforation of blades (uncommon because it is usually deep in floor of mouth & tongue)
Facial Artery
– Palpable at anterior border of masseter m. – Can be damaged by deep facial releasing incisions and by lingual drill perforations in posterior mandible
Max artery
– Gives off the inferior alveolar a. (can be damaged by invasion of mandibular canal) – Gives off palatine arteries (can be damaged by improper palatal incisions) – Gives off posterior superior a. (can be damaged by posterior superior releasing incisions) and sinus window preparation
palatine arteries
– can be damaged by improper palatal incisions (usually releasing incisions made too far posteriorly or carried too far superiorly) – can be damaged by incisions for deep split thickness flaps or connective tissue grafts
Vasculature to gingiva
and alveolar mucosa
– Terminal branches of major vessels – Critical for flap integrity & nourishment – Come from apical region to marginal and papillary gingiva – Can easily be damaged by incisions near base of flaps
Sensory innervation to most structures of concern
branches of trigeminal nerve (V)
– ophthalmic division (V1)
– maxillary division (V2)
– mandibular division (V3)
Surgical Principles
- Provide profound anesthesia
- Aseptic technique
- Antibiotics
- Atraumatic tissue management
concentrations of epinephrine > 1:100,000
• Increased concentration (e.g., 1:50,000) causes greater local
vasoconstriction but does not increase duration of action
• May increase risk of flap necrosis
Man implants and anesthesia
For mandibular implants, consider not using inferior
alveolar nerve block anesthesia (infiltration only on
facial, with block only of lingual nerve)
– decreases risk of accidental invasion of mandibular canal
– patient will “let you know” if you are getting close to
mandibular canal
– use of conscious sedation can
be an aid in these cases
– Digital radiography is BIG plus
Aeseptic Surgical Technique
• Pretreatment antimicrobial rinse (e.g., Listerine, CHX)
• Sterile instrumentation
• Sterile gloves
• Do not contaminate implant surface
• Use sterile irrigating solutions
– Required by current CDC guidelines for any surgical
procedure in which bone is exposed (meaning, implant
surgery)
– Irrigate, irrigate, irrigate (during surgery, implant
placement; thorough irrigation under flaps before closure)
Antibiotics
• For dental implant surgery, default answer has been
“YES”
– Based on original Branemark protocol
– Very little data to show benefit of antibiotics for implant
success/failure
New studies and number of patients needed to treat to prevent 1 from having a failure
to prevent one patient from having an implant failure, 33 patients
would have to receive pre‐op antibiotics
– 2013 update: NNT = 25*
Atraumatic Tissue Management
• Sharp, smooth incisions (“an incision heals better
than a tear”)
• Careful flap reflection and retraction
• Avoid flap tension
– Watch your assistant!!
– Excessive tension on a flap can cause a tear
– Excessive pressure during retraction can cause vascular
embarrassment to flap or pressure damage to nerves
Surgical Technique
- Flap design
- Incisions and flap reflection
- Implant placement
- Hemostasis/suturing
Flap Designs
– Envelope flap
– Triangular flap
– Pedicle flap
Envelope Flap
– Requires no releasing incisions – The longer the flap, the less tension is placed on the flap during retraction
Triangular flap
– Requires single vertical releasing incision – Vertical releasing incision creates greater access to underlying bone, tooth, implant; less tension on flap than with envelope flap – Can be used to avoid placing releasing incision in esthetic area or area of critical anatomy
Pedicle Flap
– Generally requires two vertical releasing incisions – Biggest benefit is ability to displace flap margin upon closure (apically positioned, coronally positioned, laterally positioned, etc.) – Excellent access to underlying bone, tooth, implant -Flap height to base should not exceed 2:1 – Releasing incisions may be nearly parallel, slight divergent, or widely divergent
Releasing incisions
– Placement of releasing incisions is critical
• Incisions should be over bone
•Place releasing incisions at line angles of teeth or
implants
•Generally do not split papilla with releasing incision
•Do not place releasing incisions over root or implant
prominences
Full thickness (mucoperiosteal) flap
Includes periosteum
Partial “Split” thickness flap
Periosteum remains attached to bone
Combination flap
part full part partial – Usually full thickness in coronal aspect, split thickness apical to mucogingival junction (periosteal releasing incision allows dramatic improvement in flap mobility) – common for procedures requiring coronal flap positioning
Incision type around teeth or implant
– Sulcular incision
– Inverse bevel (“reverse bevel” or “step‐back”) incision
Incision type in edentulous area
– Crestal incision
– Vestibular incision
– Palatally/Facially displaced incision
Sulcular incision
– preserves all keratinized tissue – easy to perform – used if clinician is satisfied with the form of the existing marginal & papillary gingiva
Inverse Bevel
– apically positions flap margin – degree of “step back” can vary depending on goal – can be used to change form of existing marginal & papillary tissue (e.g., can make more accentuated scallop)
Displaced Incision
– Incision displaced to facial or lingual/palatal, but not way out in vestibule – Supposedly prevented exposure of implant during healing (except it didn’t) • Palatally displaced incisions increased risk of flap necrosis
Incision types and success rates
Similar with ALL incisions
most common implant incision
Crestal incision with slight off‐set
Around teeth or
implants…what do I do
with the papillary
tissues?
may include or not
Papillae “preserved”
not included in flap
– Papillae remain in place – Good if clinician is happy with current interproximal tissue – May limit surgical access in narrow edentulous areas
Papillae included in flap
– Better access in limited space – Risks “loss” of papillae – Often better approach if bone is to be modified under flap (e.g. GBR procedures)
General Principles of implant placement
– copious irrigation while drilling (do not overheat bone)
– drilling osteotomy done at higher speeds (~800‐1500 rpm,
depending on system)
• Some systems use slower speeds for larger diameter drills
– implant placement done at low speeds (~15‐50 rpm)
Temperature of bone necrosis
47C
USAF birth year
Memostasis
• Must have good hemostasis before patient release
• Pressure, pressure, pressure
• Hemostatic agents rarely indicated (but may be
helpful with larger bleed)
• Do not use anesthetic agents with high epinephrine
concentrations (e.g., 1:50,000) as “hemostatic
agents”
– once the effect wears off, bleeding will resume
Perforation of mandibular
lingual cortical plate
can lead to major bleeding – Hematoma in floor of mouth – Airway embarrassment or occlusion – Death
Atraumatic Suture Technique
• Use smallest needle and suture you can for a given area
(depending on expected flap tension, etc.)
• Put sutures in keratinized tissue if you can (vs.
alveolar mucosa)
– Better resistance to flap tension
– Less discomfort for patient; easier to remove
• Take big bites of tissue; keep needle punctures away
from flap margins
• Minimum number of sutures to achieve closure
• Relieve tension from flap margins
Obliterate Dead Space
• Eliminate dead space between flap and bone
– PRESSURE!!
– prevent hematoma formation (hematoma = great
culture medium for microorganisms)
