This document discusses various types of eruptive abnormalities that can complicate orthodontic treatment outcomes, including tooth impaction, ectopic eruption, transposition, congenitally missing teeth, and supernumerary teeth. Tooth impaction is failure of a tooth to erupt and can be caused by physical impedance or ankylosis. Treatment depends on the specific abnormality and may include extraction, making space, or applying traction forces to guide eruption. Maintaining optimal arch form and function is important despite eruptive abnormalities.

1. S E M I N A R S I N
O R T H O D O N T I C S ,
J U N E 1 9 9 8
Eruptive abnormalities in
orthodontic treatment
Reginald w.Taylor
Goutam nookala
I MDS

2. Introduction
Impaction
Ectopic eruption
Tooth transposition
Congenitally missing
Supernumerary tooth
conclusion
Contents

3. Introduction
 Eruptive abnormalities complicate the
achievement of optimal orthodontic outcome.
• Eruptive abnormalities includes impacted
ectopically erupting, transposed, congenitally
missing and supernumerary tooth

4. Tooth impaction is failure of a tooth to erupt. This
failure to erupt can be attributable to to a physical
impedance of eruption path or ankylosis of tooth in
the alveolar bone
Impaction

5. The incidence of impaction in decreasing order
(a)maxillary and mandibular third molars
(b)maxillary cuspids
(c)second premolars
(d)maxillary central incisior
(e)mandibular cuspids
(f)second molars
(g)lateral incisiors
(h)first premolars

6. The treatment in these situations depends
 On the cause of impaction
 Position of the impacted tooth
 Ability to move the teeth
 Likelihood of causing damage to adjacent tooth

7. Treatment include
Extraction
Making space for the tooth in the arch, placing a
traction force to bring into arch.
 If there is adequate space- usual treatment is to
attempt to bring the tooth into arch
 If there is lack of space- then it is to be extracted.

8. Incisor impaction
Incisor is prevented from erupting into arch – due to the
hinderance by a heavy band of tissue which is usually due
to loss of premature loss of deciduous incisior.
 Treatment include surgically making a window at the
incisial edge of the tooth and packed with periodontal
dressing so that tissue does not regenerate.

9.  The incisior is then allowed to
erupt through the opening.
 It is sometimes necessary to
bond an attachment to
incisior and traction force is
applied either directly or
indirectly via chain or ligature
wire and tooth is erupted
through the open window.

10.  Although incisior impactions are encountered less
the clincal mangement of these patientsis made more
challenging because of high aesthetic importance.
 Gingival heights and countours and the region of
erption must be taken into consideration.

11. Second molar impaction
Impacted mandibular second molars are often seen
like mesial marginal ridge often caught below the
distal contact of the first molar

12. The methods of uprighting these include:
- surgically repositioning
- orthodontic repositioning.
- There is also possibility of extracting second molars
and allowing the third molars to erupt optimally

13.  Removing second molars may damage the
developing third molars.
 It has been reported very limited success in
extracting third molar and transplanting into second
molar socket.

14. Surgical uprighting of second molars is also treatment
possibility but has several drawbacks like:
 loss of vitality
 Stunted root formation
 Ankylosis and root resorption.
 While attempting to treat orthodontically geometry of
the area will dictate that an intra arch traction force will
be mesially directed exacerbating the problem.

15.  In case of distalisation it is advantageous to remove
third molars.
 To achieve molar uprighting variety of methods can be
used as
(a) separators
(b)super elastic wire open coil springs
(c)Twisted brass wire can also be used,the pig tail of
the brass wire can be twistened and tightened until the
second molar is distalised .

16. Premolar impaction
 If there is adequate space,
premolar is brought into arch in
a similar manner as an impacted
tooth and made to accommodate.
Then it is surgically uncovered
and an attachment is bonded to it
to apply traction force.
 other option is to extract the
impacted tooth and treat the
patient as if impacted premolar is
congenitally missing.

17. Ectopic eruption
 It is broadly defined as the emergence/eruption of a
tooth in a site different from its normal position
including all three planes of space;
 vertical
 Horizontal
 anteroposterior.

18. Canine ectopic eruption
 Incidence is 0.9% to 2%.
 Ectopic eruption of cuspid causes root resorption of
lateral and central or rarley premolar.
 Females > males

19.  If cuspid can be moved to its normal position without
causing or exacerbating resorption of adjacent tooth it is
moved orthodontically If not possible then extraction is
indicated.
 If the canine can be moved to normal postion without
passing in close proximity to other tooth roots then
orthodontic movement of tooth is indicated.

20.  Conversely if the clincian determines that the
amount of root strucure resorbed by ectopically
erupting canine was such as to significantly reduce
the lifespan of resorbed tooth root then extarction of
tooth is indicated and allow the canine to erupt in
the place of extracted tooth.

21. Ectopic eruption of first permeanent molar
 High incidence 2% to 6% .More in maxilla than
mandible
 There are two classes of ectopic eruption as
reversible and irreversible.
 Reversible defines a situation in which a permeanent
molar can free itself from under the distal portion of
second deciduous molar where as in irreversible it
cannot free itself

22.  If allowed to proceed ectopic eruption of the first
permeanent molar will result in premature exfoliation of
the second deciduous molar with resultant loss of arch
length
 As the main objective of treatment is to maintain arch
length,if treatment started early enough in eruptive
process uprighting the first molars and maintaining
second molars will achieve the objective .

23.  If the loss of arch length that has occurred is acceptable ,distal
surface of second deciduos molar can be reduced by discing.
 The longer the impaction continued the more the arch length is lost.
 If unacceptable loss of arch length have occurred space should be
regained first and then maintained
 The space can be regained by a variety of methods which are a
removable appliance with a finger spring,headgear,bands on first
permeanent molar and second or first deciduos molars with an
open coil spring.

25. Tooth transposition
It is eruption of a tooth in a space normally occupied by
another tooth.It is usually thought to apply to two teeth
that have exchanged the postions with in the dental arch.
 Transpositions are two types as complete and
incomplete,
 In an incomplete transposition the crowns of the teeth
have been interchanged but the roots remain in their
relative position.

26.  The roots and crowns are
exchanged in complete
transposition.
 Low incidence 0.4%
 Genetics being the most
causative factor in this
condition

27. In decreasing order
(a)canine -first premolar
(b)canine-lateral incisior
(c)lateral-central incisior
(d)canine-central incisior
 Because of difficulty in moving roots past each other
without causing other damage,these are treated
optimally in their transposed positions.

28. Congenitally missing teeth
 Hypodontia or congenitally missing teeth is most commonly
encountered anomaly
 Incidence is 3.5%to 8%
 After taking 3rd molars into account,the most commonly
missing teeth are second premolars and maxillary lateral
incisiors
 It is important to note that different races have different
predilections,for an instance most commonly missing teeth in
asian dentition are mandibular incisiors

29.  Cause may be multifactorial
 Treatment depends on number and position of missing
teeth
 If there is crowding anticipated in arch then missing
tooth may be used like extraction space.
 Otherwise the space can be restored by removable partial
denture,resin bonded paratial denture or an osseo
integrated implant anchoring a fixed restoration.

31. Supernumerary teeth
 It is defined as those
teeth in excess of normal
dental formula.
 Incidence range is 0.1%to
3.6%
 76%-80% of patients with
Supernumerary teeth
have only one
Supernumerary teeth

32.  The most common area in which supernumerary teeth
are found is premaxilla,specifically mesiodens,which is
located between central incisors
 The other regions include in descending order
 (a)maxillary third molar
 (b)mandibular third molar
 (c)mandibular premolar
 (d)mandibular incisior
 (e)maxillary premolar

33.  Supernumerary teeth can be classified either by location or their
shape.
 When classified by location they are termed as
 Mesiodens,between centrals
 Paramolar between second and third molars
 Retromolars distal to third molars
 Parapremolars in the premolar region.
 The shapes are divided into supplemental and rudimentary.
supplemental teeth have normal size and are difficult to distinguish
from a normal tooth.

34.  Rudimentary teeth are further
divided into conical,tubercular
and molariform
 The position of Supernumerary
teeth can cause crowding
malalignment/disruption to
normal dentition
 Because of this disruption it is
extracted or correctly align in
the dental arches.