orthodontic management and treatment of impacted incisors , canines and wisdoms (third molars )

1. Dr Abdelrahman Mosaad , BDS

2. Most common
impactions

3. 1 )Mandibular 3rd molars
(wisdom ) impactions :

4.  lower third molars is a common clinical finding, with a
prevalence between 9.5% and 39% among different
populations
 Mesioangular impaction is the most common type,
occurring in 43% of the cases involving lower-molar
impactions

5.  N.B. the second molar partial or total impaction with a
reported incidence of 0.03–0.3% of the general
population , and 2–3% of orthodontic patients

6. Risk during wisdom extracion sugecally
or non-surgecally :
 inferior alveolar nerve injury
 TMD
 Dry socket
 Mandibular faractures

7.  Complications are more likely to occur in cases of
mesioangular and horizontal impactions

9. A. Compressed nickel titanium spring generates mesial and distal forces
(green arrows); distal force is applied at level of distal molar cusps (blue
arrow). Significant uprighting moment and distal force are generated at
center of resistance (red arrows).
B. Wire slides through slot of mini-implant head during uprighting of
impacted molar

10. A. Buccal eccentric force applied by uprighting mechanics
generates clockwise moment on third molar, causing distal
rotation.
B. To counteract this effect, wire is bent distally before insertion
into molar tube, generating counterclockwise moment

12.  Because the uprighting moment is generated by
eccentric force application on the molar, the moment
becomes larger as the distance between the point of
force application and the molar's center of resistance
increases
 i.e the distal cusps are a more effective application
point than the buccal crown surface

13.  An axial direction of force could actually be favorable
in a case with residual space mesial to the tipped molar
due to loss of the adjacent molar, where a mini-
implant of larger diameter could be inserted vertically
into the alveolar process

14. Case

16. 6 months

17. Case 2

18. 1 month

19. 24 months

20. Case 3

21. Tilted
tipped

25. 17 * 25 TMA
wire

27. Uprighting mechanics

33. Initial T loop
Modification for severely tilted
T loop spring
17*25 st.st
19*25 betaTi

34. 2) Canine impactions :

35.  Canine impactions involve 0.92% of the white
American population. Epidemiological data shows
different incidences among other populations.
• Finnish = 1.8 % • Swedish = 1.7 % • Italian
= 2.4 %
• Japanese = 0.27 % • White American = 0.92 %

37.  Canine impactions are more frequent among females
than males (F : M = 2.3 : 1) or 1.17% of females and
0.51% of males
 85% of impactions are palatal impactions compared to
15% that are vestibular impactions.
 Palatal bulge , retained c , x-ray

40.  keeping a primary canine in the mouth beyond the
timeframe where it should normally shed
guarantees that the permanent canine is either ectopic
or impacted

41. Complications :
- Granulomas
- Cysts
- tumors
- Ectopic eruptions
- Root resorptions

42. Preventive diagnosis
The permanent canine normally erupts around 11-12 years of age. It
is thus wise to verify its position and its evolution as early as 9-10
years of age. We must suspect that an anomaly can occur if we
observe:
• A microtooth or a congenital absence of a lateral incisor
• An overall delay of eruption
• The retention of the primary canine beyond 12-13 years of age
without any signs of moving
• A palpable palatal vault
• A congenital absence of premolar(s). One or more absent
premolar.
• An ankylosis of a second primary molar
• A lateral incisor in labioversion, palatoversion, distoversion

43.  When the patient is between 10 and 13 years old
interceptive diagnosis takes place .
 The relative position of the permanent canine with
regard to the adjacent teeth is an important factor in
the success of the interception. By success, I mean that
the canine will go back to a normal path of eruption

44. Erikson and Kurol developed a little evaluation
diagram. If the tip of the unerupted canine does not go
past more than half of the root of the lateral
incisor (zone 2 and 3) and the inclination angle related
to the medial plane is not greater than 55o
>>> the average success rate (normal eruption) is
about 80%. This means that 80% of the cases showed a
normalization of the canine eruption in the 6 to 12
months following the extraction of the primary canine

49.  If the permanent canine is in zone 1-2, the success rate
is about 90%. If the canine goes past the lateral incisor
and the tip is in zone 4, the success rate decreases
to 64%.
 If no improvement Is observed, then the
autocorrection prognosis is weak and a procedure
must be considered
 N.B. auto-correction with normal canine eruption after
extraction of primary canines may take up to 2 years
according to the case

50.  Ericson S, Kurol J. Early treatment of palatally erupting
maxillary canines by extraction of the primary canines.
Eur J Orthod 1988;10:283-295.

51.  important factors regarding treatment of
impacted canines are:
 The horizontal position of the impacted tooth (degree
of overlap with the lateral and central incisors).
 The patient’s age.
 The height or vertical position of the impacted tooth.
 The oro-palatal position of the impacted tooth

52. CBCT diagnosis

56. ttt

57. 17*25 at 60 gm

58. Lower 3s technique

60. case

65. Mechanics of lower

66. Case
Months

68. Case 3

70. Case

72. Case

77.  N.B. Becker et al. reported that repeat surgery was
required for 62.9% of the impacted canines in which
corrective treatment was started, mostly to redirect the
ligature wires with the guidance of the 3-dimensional
imaging

78.  If, the tooth does not show clear evidence of
movement after six months of orthodontic force
application, a re-evaluation is necessary. Ankylosis,
one of the major complications associated with
impacted canines, can rarely be detected based on
clinical and conventional radiographic examinations
however CBCT provides a better diagnosis of the area
of ankylosis

79.  The percentage of ankylosis was 3.5% in the open
technique and 14.5% in the closed technique. They
have defined anyklosis as impacted canines being
immobilized a priori or during traction, due to all the
possible causes that could contribute to
immobilization, such as all types of external tooth
resorption and other known or unknown factors

80.  D'Amico et al. reported the adverse effects of the
orthodontic-surgical treatment for impacted maxillary
canines in the long term conducted in a sample of 61
cases. 6.5% of the patients were dissatisfied with the
esthetic results, whereas the orthodontist estimated
the results as good in only 57% of the cases

81.  Woloshyn et al evaluated the posttreatment changes
nearly 4 years after treatment and compared the
differences in the periodontal and pulpal status, root
length, and tooth alignment between the side of the
forced-erupted ectopically canine and the contralateral
side.
 The probing attachment level was found lower on the
mesial and distal aspect of the previously impacted
canines, also the roots of the adjacent teeth were
found shorter.

82.  The incidance of pulpal obliteration was 21% in the
previously impacted canines. Significant
posttreatment changes such as intrusion, lingual
displacement, rotation, and discoloration was
determined in 40% of the previously impacted teeth
where as 91% had a normal appearance on the
contralateral side

85. 1. If it is ankylosed and cannot be transplanted
2. If it is undergoing external or internal root resorption
3. If its root is severely dilacerated
4. If the impaction is severe i.e. the canine is lodged between
the roots of the central and lateral incisors and orthodontic
movement will jeopardize these teeth)
5. If the occlusion is acceptable i.e. with the first premolar in
the position of the canine and with an otherwise functional
occlusion with well-aligned teeth
6. If there are pathologic changes (e.g., cystic formation,
infection
7. If the patient does not desire orthodontic treatment
When to extract ?

86.  N.B. labially impacted canines are more challenging to
manage without the occurrence of adverse periodontal
problems
 So , special attention has to be given to surgical
technique, marginal gingival placement, control of
inflammation, magnitude of force, atraumatic surgery,
and proper gingival attachment

87.  3 techniques are used for uncovering a labially
impacted maxillary canine :
excisional uncovering (gingivectomy)
apically positioned flap
closed eruption techniques
The orthodontist should be the guide to the surgeon to
efficiently manage the case surgecally

90. Excisional uncovering
Apically positioned flap

91. Closed flap eruption

92. Closed flap is
the choice
All techniques
could be done
Apically positioned
flap could give good
results

93.  Evaluate the canine position Mesiodistally , mesially
positioned canine toward the roots of lateral central
could require apically positioned flap
 Evaluate the amount of gingiva could be present after
the canine euprtion , at least 2 to 3 mm of attached
gingiva over the canine crown after it had been
erupted is needed for good esthetic results

94.  the labiolingual position of the impacted canine crown
should be determined. If the tooth is impacted
labially, then any of the 3 techniques could be
performed, since there is usually little or any bone
covering the crown of the impacted canine.
 However, if the tooth is impacted in the center of the
alveolus, an excisional approach and an apically
positioned flap are usually more difficult to perform,
for large amount of bone removal might be required
from the labial surface of the crown

100. Piggyback

101. Tunnel

102.  Palatally positioned canine :
 With palatal impactions it is critical to recognize
that the entire palate is covered with specialized
mucosa
 The surgical methods for exposing the impacted
canine are:
open surgical exposure and allowing for natural
eruption
open surgical exposure and packing with subsequent
bonding of an auxillary
closed surgical exposure with the placement of an
auxiliary attachment intraoperatively.

105.  The orthodontic force to be applied to the bonded
attachment requires careful planning
 the tooth should be erupted vertically and once a
facial attachment can be bonded, forces should direct
the tooth facially

106.  During closed-eruption technique, the orthodontist
should select mechanics that erupt the tooth through
the center of the alveolar ridge. The eruption of the
tooth between the alveolar cortical plates prevents
bone dehiscence and unfavorable orthodontic and
esthetic consequences

107. impaction canine brought vertically then labially

108. Kilroy 18 st.st

109. Ballista 18 stst

111.  in recent studies evaluating the differences in the
periodontal outcomes of palatally displaced canines
(PDC) exposed with either an open or a closed surgical
technique, no significant differences in post-treatment
periodontal status of the canines and adjacent teeth
were determined between the techniques.
 Both treatment methods were found acceptable for
treatment of the palatally impacted canine

112. 3) Impacted upper centrals :

113.  The current prevalence of impacted maxillary central
incisors has a rate of 0.06–0.2 % according to the some
available literature . In a referred population to
regional hospitals the prevalence has been estimated
as 2.6%
 Unerupted incisors are more common in males than
females with a ratio of ( 2.7 : 1 )

114.  any retained deciduous teeth or supernumeraries
should be removed if the incisor is close to eruption
 When space is created for eruption, 75% will erupt
spontaneously ; out of which 55% will align
spontaneously ( spontaneous alignment and eruption
may take about a year and half – 3 years ( 18-36 months
)

115.  Almost half (47%) of all unerupted maxillary incisors
are due to supernumeraries
 The mesiodont variety has more eruptive disturbances
compared to the palatodont

116.  Early clinical examination with radiographic
investigation at age of 6-8 years can detect presence of
unerupted maxillary incisors which would allow early
interception and monitoring and thus may improve
treatment outcome.

117.  The incidence rate of dentigerous cyst affecting the
permanent incisor is approximately 1.5% ,
marsupialization or decompression technique is the
treatment of choice in young patient with teeth could
furtherly erupt

118. Surgery

119. RCSE recommendations

121. Do you remember ?

122.  Criteria to evaluate when considering
the best surgical approach :
1. Labio-palatal Position of the Unerupted Tooth ,, all
techniques will work in cases of labialy impacted
central
2. Vertical position of the unerupted tooth relative to
the mucogingival junction
3. The amount of gingiva in the area of the unerupted
tooth
4. The mesio-distal position of the crown of the tooth

123. case