Dentoalveolar Surgery Flashcards
Order of impaction frequency
1-3rd molars
2-Max canines
3-Mandibular premolars
4-Max premolars
5-second molars
Rarely impacted teeth
1-Mandibular incisors
2-1st molarsf
Eruption pattern-Primary
Eruption pattern-permanent
Local vs systemic factors for tooth impaction
How to tell if a tooth is buccal or lingual from panoramic
If tooth is larger, out of focus, likely palatal.
If tooth is vertical, likely buccal
Describe cone beam computed tomography?
Conventional medial CT scanner uses fan-shaped beam to obtain individual image slices with each slice requiring a separate scan; slices stacked to get 3 dimensional rotation
Why does CBCT have less radiation
It is directed through middle of area and covers entire field of view, only one rotation needed; so less radiation
How does dose vary on CBCT
-slice thickness
field of view
mAs, kVP
Scan time
what is a gray or rad?
Absorption of 1 joule of radiation energy by 1 kg of matter
Sievert
Effective dose or quantification of potential radiologic detriment (cancer induction, genetic damage) from radiation
Bear in mind that 10,000 uSv single exposure = 1:1000 personal exposed will develop cancer.
What does it mean if an impacted canine/premolar is labial?
If palatal?
It means there is an arch-length deficiency.
If palatal, likely from extra space in the maxilla, excess growth, agenesis/peg lateral incisor, or stimulated eruption of lateral incisor or first premolar
How to help an impacted 2nd molar succeed?
In maxilla, remove and allow for the third molar to swing in.
That doesn’t always work in the mandible.
What is the ideal time to surgically uproot a canine?
2/3rd of root formation, with incomplete apical closure
What happens if you try and upright a 2nd molar too early?
tooth may move into wrong position.
If too late, pulpal necrosis/calcifcation maye occur leading to possible root fracture.
How to ensure appropriate surgical uprighting of a 2nd maxillary molar
1-Extract 3rd molar to posteriorly tip.
2-Need intact cortical plates for stability
3-Avoid damaging 2nd molar CEJ
4-Do not tip more than 90 degrees
5-Splint to first molar
6-Ensure tooth is out of occlusion
True or False? do you expose CEJ on an expose and bond?
False, do not expose CEJ –increased risk of root resorption, ankylosis, periodontal inflammation.
How to approach a mandibular premolar that is in the alveolar process?
Bond to the occlusal surface….apply vertical orthodontic forces until buccal surface exposed for new bracket placement.
Why is an apically positioned flap important
Allows erupting into attach mucosa and is less likely to have a periodontal defect with pocket formation.
What’s the normal eruption pattern of a 3rd molar
(6 stages)
What explains rotations of 3rd molars
1-Underdeveloped medial root-Under rotation = mesioangular impaction
2-Overdeveloped medial tooth with over rotation = distoangular impaction
3-Overdeveloped distal root (especially with medial curve) = severe mesioangular or horizontal impaction
By what age will tooth likely remain impacted if there is improper angulation or inadequate space?
18-20
Shorter arch or larger teeth leads to?
More impacted teeth
What is the Pell & Gregory Classification system?
Based on relation to occlusal plane and anterior border or ascending ramus
What is Winter classification
Baseront radiographic anatomical position of 3rd molar related to long axis of 2nd molar
What is the most commonly found impacted tooth?
Mesioangular at 45%
What three bacteria are often associated with pericoronitis?
Peptostreptococcus
Fusobacterium
Prophyromonas
What is the most common indication for extraction after 20
pericoronitis
What are symptoms of periocoronitis?
Associated with inflmmation of the operculum with pain, swelling, erythema, and purulence
What is the recommendation for removal of 3rds prior to surgery?
6-12 months to allow for adequate bony fill
What are periodontal considerations for wisdom toooth removal
1-Disrupted per ligament
2-Root resorption
3-Pocket Depths > 5 mm
T/F: Periodontal healing is best when…
3rd molars are extracted before exposure in the mouth and before bone resorption on the vital of the 2nd molar
Germectomy…
Perform when < 1/3rd root formation and radiographically discernible periodontal ligament.
If age is greater than 25, what are the thoughts on 3rd molar extraction?
1-Only remove if pathology is present
2-30% chance of increased pocket depth associated with 3rd molar removal
3-Post-operative morbidity is 1.5 times higher.
4-After age 19, preoperative and postoperative defects are the same.
What is the leading cyst associated with 3rd molars
1-Dentigerous cyst (28%)
2-OKC (3%)
3-Odontoma (0.7%)
4-Ameloblastoma (0.3%)
5-Carcinoma-(0.23%)
6-Myxoma-0.04%
T/F: decreased risk of neoplastic changes in 3rd molar follicle in patient’s older than 40
True
What is the indication to extract a 3rd molar for an overlying prosthesis
If 1-2 mm of bone or only soft tissue is overlying the tooth, then the tooth should be extracted.
How much do 3rd molars increase the risk of an angle fracture?
2.8 x fold
Contraindications for 3rd molar extraction
1-Too young (no younger than 9)
2-Too old, >40 yrs
3-Med Compromise
4-Damage to nerves
What is the indication to leave a root behind?
If root is not infection ed and less than 2 mm long, okay to leave without complications.
requires close radiographic follow up
If root of tooth is displaced lingually and it cannot be retrieved, how long should you wait before retrieving it?
3-4 weeks.
What is the most common root dislodged into the sinus?
Maxillary palatal root
Local measures to retrieve a root from the sinus?
1-Close nostrils, blow through nose
2-Fine-Tip suction
3-lavage with saline
4-pack iodoform gauze
5-Caldwell Luk in canine fossa
What are the borders of the infra temporal fossa?
What to do if tooth is dislodged into infra temporal space?
1-Finger pressure in buccal vestibule near pterygoid plates to manipulate back into the socket.
2-Access with hemostat
3-Suction
4-Close up and go again after 3-4 weeks with abx.
3 dimensional imaging, right angled hemsotat to bring back into position.
How to stop bleeding vessels?
1-Burnish bone,
2-Crush surrounding bone
3-Apply wax
4-Cautery
5-Could be contaminant nerve injury.
What is gelfoarm?
reservable porcine skin gelatin sponge that promotes platelet disruption the forms fibrin framework then blood clot.
Can be hoisted in thrombin (which activates blood coagulation factor II and converts fibrinogen to fibrin
What is surgicel?
Oxidized cellulose plat polymer of polyanhydrogucoronic acid
More efficient than sponge, but delayed healing
-Forms matrix/scaffold then artificial blood clot
-Resorbed between 7-14 days
-Creates acidic environment and not the best for overlying the nerve.
What is a collaplug
A bovine collagen plug that is resorbed in 10-14 days
What is thrombin?
A bovine or recombinant human that activates blood coagulation factor IIa, then conveys fibrinogen into fibrin
What is amincaproic acid?
Antifibrinolytic that inhibits plasmin
What is transexamic acid
Inhibits conversion of plasminogen to plasmin
What can you do to work up coagulopathy?
-CBC
-PT/INR
-PTT
-Bleeding time
-Factor 8 levels
-Ristocetin cofactor levels
Where is the most common place of an oroantral communication
The first molar site
How to treat oroantral communication?
for 2 mm
3-6 mm
> 6 mm
1-If opening is greater than 2 mm, please suture over socket to support clot, no blowing nose for 1 week
2-3-6 mm, gelatin sponge pack, figure of eight suture over socket,
3-If opening > 6 mm, tension-free primary closure, excise fistula and invert into sinus.
What are options for closure/
1-Buccal advancement
2-Palatal island/finger flap. rotational flap
3-Pedicled buccal fat pad
4-Tongue flap-
What is the blood supply of the buccal fat pad
the internal maxillary artery
How long before you release a tongue flap?
2-3 weeks and the patient must be in MMF
What are the bacteria associated with sinus disease?
1-Streptococcus pneumonia
2-Haeomphilu sinflueze
3-Moraxella catarrhalis
What antihistamines and decongestants should be used for oroantral communications?
1-Amoxicillin, Augmentnin,
2-Antihstamines-Certirizine, diphenhydramine, fexofenadine, loratidine
3-Decongestants: Pseudorephedrine, tripolidine, oxymetazoline
Risk factors for a mandible fx with 3rds?
1-Pt older than 40 years
2-Male
3-Atrophic jaw
4-Associated cyst/tumor
5-osteoporosis
6-Inexperienced surgeon
Can occur 14 days after say, but can occur up to 6 weeks postoperatively
Where is the IAN often located?
buccal and apical to mandibular tooth roots?
What is the incidence of injury to IAN in 3rd molar surgery?
1-5%
What are the Rood criteria?
1-Loss of IAN canal wall–cortical (white) lines
2-3rd molar root darkening
3-Narrowing of IAN canal as it passes 3rd molar root
4-Diversion of IAN canal
5-Deflection of roots
6-Bifid root apex
Risk factors for nerve injury (7)
1-Age > 25 years
2-Female > Male
3-Tooth elevation stretching nerve
4-Instrumentation near nerve
5-Socket curettage
6-Socket medications
7-Articaine blocks
Indications for a coronectomy
1-No pathologic legion
2-No interference with future restorations or orthodontic treatment
How much reduction of the tooth must be performed for a coronectomy?
3 mm below crestal bone
Most common presentation of lingual nerve
2.5 mm medial and 2.5 mm inferior
How many lingual nerve occurs above the lingual plate?
10-15%
% of lingual nerves directly attached to lingual plate
25%
What often causes nerve damage?
Injection into epineurium can cause hematoma and transiet/permanent paresthesia.
Where does sensory innervation and taste of the lingual nerve come from?
Anterior 2/3 of tongue is supplied by CN VII carried along CN V
Nociceptor:
A receptor excited by injury/painful sensation
Wallerian degernation
Fatty degeneration of the nerve fiber
Layers of nerve fibers
Endo–>Surrounds gorupof fibers–>forms fasicle
Peri–>Surrounds group of fascicles
Epi:Outermost layer that surround the fascicle bundles and blood vessels–>protects against compressive forces.
What are the. 2 nerve injury classification systems?
1-Seddon
2-Sunderland
What is neuropraxia?
Seddon I and Sunderland I-Minor ompression/traction temporary conduction blockade