Maxillary Canines Flashcards
What is the second most commonly impacted tooth?
Maxillary canines
What is the prevalence of impacted maxillary canines?
1.7%
Where are maxillary canines often impacted? Why?
- 80% PALATALLY ECTOPIC.
- Tooth germ of permanent canine originates on the PALATAL aspect of the arch.
When should maxillary canines be palpable?
- Palpable in the LABIAL SULCUS by 10-11 years.
- Also palpate hard palate to see if you feel a bulge.
11 causes for canine impaction?
- Lack of space.
- Absence of lateral incisor to guide eruption.
- Genetic theory
- Non resorption of deciduous teeth.
- Ankylosis of impacted canine.
- Contraction or collapsed maxilla arch.
- Presence of pathology/ supernumerary/ scar tissue in path of eruption.
- Trauma causing a disturbance in tooth germ axis (ex. dilacerated).
- Cleft lip and palate, syndromes, cleidocranial dysplasia.
- Long path of eruption (22mm).
- Displacement of the crypt.
What is the guidance theory?
The distal aspect of the lateral incisor is the guide for canine eruption. can also be because the lateral is. PEG LATERAL.
How long is the path of eruption for a canine?
22mm
6 clinical tests/ signs that there might be an impacted maxillary canine?
- Palpate.
- Evidence of rotation/ tilting of adjacent teeth.
- Mobility/ sensibility of adjacent teeth.
- 6 months since contralateral tooth erupted.
- Presence of deciduous canine.
- Family history of impacted canines.
Why is sensibility/ mobility testing indicated when investigating a potentially impacted maxillary canine?
Could be due to EXTERNAL ROOT RESORPTION typically of the 2 but could be of the 1.
3 ways to raidographically investigate an impacted canine?
- Vertical parallax (maxillary occlusal + DPT).
- Horizontal parallax (2 PAs).
- CBCT
What is the slob rule?
Same lingual opposite buccal.
3 uses of DPT for investigating impacted maxillary canines?
- Root morphology
- Assess for pathology.
- Assess for positioning using vertical parallax.
What does an enlarged follicular space suggest? What is a normal size of follicular space.
- Follicle could be undergoing CYST FORMATION.
- Normal/ expected space is around 3-4mm.
What is the treatment for dilacerated teeth?
- CANNOT be ORTHODONTICALLY ALIGNED/ TRANSPLANTED.
- Either XLA or leave alone if pathology-free.
- If XLA then orthodontic closure of space OR orthodontic opening of space and an implant.
3 sequelae of canine impaction?
- Resorption of incisor roots (up to 12.5%).
- Cystic change (incidence low).
- Infection of cyst when close to mucosa, possible sinus formation.
How can impacted canines cause incisor resorption? How prevalent is this?
- Canine must be SUPERFICIAL (almost at line of the arch) and NOT IN A VERY HIGH POSITION aka must be INTIMATELY RELATED WITH THE ROOTS OF THE INCISORS.
- up to 12.5%.
What indicates cystic change? What is the cyst called?
- Expansion of the follicular space.
- DENTIGEROUS CYST.
3 sequelae of cyst formation?
- Resorption of adjacent teeth.
- Resorption of bone.
- Can penetrate through mucosa and become infected.
5 treatment options for impacted canines?
- Conservative
- Interceptive
- Exposure
- Surgical removal
- Transplantation
4 clinical indications for a conservative approach?
- Patient does not want ortho.
- Patient happy with aesthetics + good contact between 2 and 4.
- Adjacent teeth vital.
- Healthy C.
2 downsides to retaining a C? Till around what age can it remain healthy?
- Prone to attrition.
- Short roots means composite buildup would cause poor crown-root ratio + not very aesthetic result.
- around 40 years.
3 radiographic indications for a conservative approach?
- Tooth very high.
- No associated pathology.
- No resorption.
usual after 14 years of age.
3 clinical indications for an interceptive approach?
- Patient 10-13 years.
- Minimal crowding.
- Space maintenance.
When would you expect the permanent canine to erupt with the interceptive approach? How often does this occur?
- Expect permanent canine to erupt WITHIN 6 MONTHS.
- If no change in position after 12 MONTHS alternative treatment.
- Erupts normally in 78% of cases.
2 clinical indications for exposure and alignment?
- Well motivated patient (orthodontics + OH).
- Best done early.
2 radiographic indications for exposure and alignment?
- Not grossly displaced.
- Favorable root morphology (STRAIGHT, CONICAL ROOT).
What are the 2 techniques for exposure and alignment of a maxillary canine?
- open technique: apically repositioned flap or palatal window.
- closed technique: orthodontic bracket and gold chain allowing orthodontic traction.
Indications for an apically repositioned flap (3)?
- Tooth BUCCALLY placed or in LINE OF THE ARCH + VERY SUPERFICIAL.
Risks of an apically repositioned flap?
- Suture gingivae much higher to leave eruption path unimpeded.
- Risk of EXPOSED CANINE ROOTS (abrasion, sensitivity, poor aesthetics).
Process of carrying out a palatal window (5)?
- Lift mucoperiosteum + remove bone and follicle to reveal crown.
- Cut a WINDOW into the soft tissue.
- Suture flap back.
- Make an ACRYLIC/DRESSING PLATE held on my ADAMS CLIPS, packed with COPACK SOFT TISSUE DRESSING.
- Leave undisturbed for a WEEK. Clean with MOUTHWASH + brush teeth away from the surgical site.
What can be used to hold back a palatal mucoperiosteal flap?
Howarth periosteal elevator.
Post op palatal window advise?
- Keep dressing plate with copack soft tissue dressing undisturbed for a WEEK.
- Clean using MOUTHWASH + BRUSH teeth away from the site.
What is the best exposure and alignment technique? Why?
CLOSED TECHNIQUE.
- MIMICS THE PHYSIOLOGICAL ERUPTION OF THE CANINE, ERUPTS THROUGH ATTACHED GINGIVAE THUS HAS GOOD GINGIVAL CONTOUR.
What kind of flap is done for closed technique exposure and allignment?
- APICALLY REPOSITIONED FLAP.
- Bond orthodontic bracket with chain onto the crown prior to attaching to an orthodontic device.
Incisor root resorption prognosis?
IF MORE THAN 1/3RD OF THE INCISOR ROOT HAS BEEN RESORBED, THEY HAVE VERY POOR PROGNOSIS.
6 indications for surgical removal of impacted canines?
- Non compliant patient.
- Patient happy with C.
- Patient happy with 2 and 4.
- Advanced resorption of incisors.
- Canine malpositioned + poor root morphology.
- Canine malpositioned + pathology.
When would you need to section a canine during surgical removal (2)?
- Horizontally impacted against incisors (take crown off to create space to elevate the roots).
- Dilacerated tooth where path of withdrawal different from path of withdrawal of root.
May need BUCCAL approach for sectioning.
What flap design is used for surgical removal of impacted canines?
LARGE ENVELOPE FLAP.
Unilateral impacted canine?
Flap from CONTRALATERAL INCISOR to at least FIRST PREMOLAR.
Bilateral impacted canine?
Flap from premolar to premolar.
Anatomical structure involved in the flap design for surgical removal of maxillary canines?
NEUROVASCULAR BUNDLE through INCISIVE FORAMEN
- Unilaterally: ok, enough stretch in the flap to put tension and allow access.
- Bilaterally: may have to SEVER the neurovasculae bundle.
What must do you place on the neurovascular bundle? Why?
SPENCER WELLS ARTERY FORCEPS to prevent bleeding before releasing it.
Effect of severing neurovascular bundle?
- Not an issue as PATIENTS DO NOT COMPLAIN OF NUMBNESS OF THE ANTERIOR HARD PALATE
- INNERVATION IS TAKEN UP BY GREATER PALATINE NERVES OVER TIME.
Where is the flap for a surgical removal of maxillary canines placed?
Commonly PALATAL, same flap as for exposure.
5 steps to surgical XLA of maxillary canines?
- Raise flap.
- Take off overlying bone to expose the MAXIMUM CONVEXITY of the tooth.
- Defolliculize the tooth.
- Create a point of application.
- Use an ELEVATOR to elevate the tooth out of the socket.
Where is follicular tissue attached? Why must this be removed?
- Attached at the AMELO CEMENTAL JUNCTION.
- Must be removed ENTIRELY or can undergo CYSTIC CHANGE.
5 clinical indications for canine transplantation?
- Poor patient compliance.
- Limited treatment time desired.
- Poorly positioned canine (too far to be surgically exposed but can still be surgically accessed) WITHOUT ANKYLOSIS.
- Open apex desirable.
- Need adequate space and bone.
What other tooth can be transplanted?
Mandibular 3rd molar transplanted into 1st molar position.
What is the failure rate for transplanted maxillary canines? 4 ways it fails?
- 30% over 9 years often due to poor surgical technique.
Causes:
- Internal root resorption (perform RCT).
- External root resorption (excessive force on tooth in socket).
- Replacement root resorption (root replaced by bone until it exfoliates).
- Infection
Why is an open apex desired for the transplantation procedure?
Some chances of re-establishment of blood supply to tooth.
5 steps to transplantation procedure?
- Access as for removal.
- Atraumatic elevation avoiding contact with PDL/ root.
- Tooth “parked” in tissues to ensure it does not dehydrate.
- Prepare socket with burs or chisels - Socket “friction fit” avoiding heat generation.
- Immoblize with a SPLINT + ensure it is FREE OF OCCLUSAL LOADING.
How quickly do we want the transplantation procedure to be completed?
Ideally in LESS THAN 10 MINUTES.
What must be done post-op after transplantation (4)?
- Immediately splint tooth.
- Ensure it is free of occlusal loading.
- Check vitality.
- Check for resorption.
