The unerupted maxillary canine Flashcards
What is the prevalence of ectopic canines?
- Low prevalence but high
in risk for GDP - Prevalence 2%
What is the prevalence of ectopic canines bucally?
- 5 percent
Line of the arch?
34 percent
Palatal?
61 percent
What is the problem with ectopic canines?
Root resorption
Incidence using plane radiographs?
12 percent
Incidence of ectopic canines using CT?
48 percent
Incidence of ecoptic canines using CBCT?
67 percent
Why does root resorption occur?
- Crowding/shortening of arch length
- Adjacent lateral incisor missing or abnormal in shape or size
- Long path of eruption
- Palatal = genetic; buccal = inadequate arch space
Brin, Becker & Shavlav, 1986…
- 2,500 patients with ectopic canines
- 43% had absent or small lateral incisors
Study shows that?
- Length of the root more critical than
What should you do if the canine is
not palpable buccally at 9-10 years?
Check – bulge, inclination and
colour of adjacent teeth.
Palpate – for the canine crown
buccally and palatally,
check for mobility of the
2 and C.
Radiographs – (parallax) Presence
Position
Pathology
What is parallax?
Physics / General Physics)
an apparent change
in the position of an object resulting from a
change in position of the observer
The principle of parallax can be used
The position of parallax can be used
to determine
the position of an unerupted tooth relative to its
neighbours.
When do we use it?
Palpate for canines when a patient is 9-10 years old
Index of suspicion is raised if?
the pt has a
missing, or abnormally shaped lateral
incisor;
has spaced arches, or
if palpation
indicates an asymmetrical eruption pattern
Clinical signs of a palatally impacted canine?
- Delayed eruption of 3 or prolonged retention of
the C - Absence of normal labial 3 bulge or presence
of a palatal bulge in the 3 region. - Delayed eruption, distal tipping of migration of
the lateral incisor. - Loss of vitality and increased mobility of the central or lateral incisor
Why do we use it?
- Knowing the location of the ectopic canine
allows us to treatment plan more
accurately. - If not managed correctly an ectopic canine
may resorb the root of the adjacent
incisors. This may result in a medico-legal encounter
How do we do it?
Horizontal parallax?
2xIOPAs (at least 20 degrees of tube shift needed)
Anterior occlusal and IOPA
Vertical parallax
Anterior occlusal and OPT
IOPA and OPT
How do we interpret it?
Tube movement for vertical from OPT to anterior occlusal the beam moves up
Tube movement for horizontal from IOPA to anterior occlusal the beam moves up
Pal with and buccal against
Studies suggest that which paralax is most effective in locating palataly ectopic canines?
Percentages?
Horizontal (88 percent vs 69 percent with vertical)
What about buccal ectopic canines and paralax?
Same effectiveness in being located with horizontal and vertical (63 percent)
To conclude the Armstrong et al paper suggested what about. DPTs and horizontal paralax?
That DPTs shouldnt be used in the investigation of canine ectopic where radiographs that allow horizontal paralax should be taken
Power and short study suggests- extraction of the deciduous canine in attempt to realign the palatally ectopic canine…
Success rate (in crowded dentitions)
62 percent
What percentage improved indicating that crowding adversely affects the outcome?
19 percent
How does crowding affect the prognosis for correction of palatally ectopic canine?
Crowding reduced the prognosis
Leonardi et al 2004
Longitudinal prospective control study
Isolated extraction of C success rate?
50 percent success
Untreated control group?
50 percent success
Creation of more space plus extraction of C?
80 percent success
Extraction of the deciduous canine should occur at what age
10-13
What should you consider the need for in extraction of the deciduous canine?
Balancing extraction
Better prognosis if?
No crowding
Need to create space for?
URA or HG
If no improvement in 12 months consider
Alternative treatment
Extraction of the deciduous canine will often be a treatment of choice but
The decision should be left to a specialist orthodontist
Why?
Why? – the ectopic canine may not be ‘alignable’ and you may have extracted a highly useful tooth
Surgical exposure and orthodontic alignment- criteria for a patient?
(5)
- Willing to wear fixed appliances
- Well motivated and have good dental
health - Unsuitable for interceptive treatment
. Degree of malposition not too great
What 3 things do you have to consider for the degree of malposition?
Apex position
Crown position
Angular ion
Surgical exposure can be … or …
Open or closed exposure
For long term perio health, 1-2 years after debond looking at attachment loss and pocket depth what is the conclusion?
There is no evidence that either method is superior
Cost analysis for deciduous canine exposure (surgical)
Interceptive involves?
Extraction of C
Surgical involves?
- Oral surgeon
- General anaesthetic
- 18 months of fixed
appliance treatment
What are the treatment options for ectopic canines? (5)
- No treatment and observe long term for
cystic change - Interceptive treatment where
appropriate - Exposure and alignment
- Extraction
- Transalveolar transplant or surgical repositioning
Orthodontic treatment risks?
- Risk of root resorption to adjacent teeth
(lateral incisor and first premolar) - Risk of pulpal obliteration to canine and
adjacent teeth causing colour mismatch. - Risk of discontinued treatment due to
prolonged treatment times. - Canine ankylosis.
. High tendency to relapse
Key points for ectopic canines
Age?
Palpate for canines at the appropriate age (9-10 yo)
Horizontal vs vertical paralax
Horizontal paralax is more accurate than vertical
What could be the result of missed ectopic canines
Root resorption
