Key-words:
Adult - anterior crossbite - Libyan
Introduction
An anterior crossbite is present when one or more of the upper incisors are in lingual
occlusion relative to the lower incisors.[[1]] On the other hand, under normal circumstances, the maxillary teeth overlap the
mandibular teeth both labially or buccally.[[2]] However, when the mandibular teeth, single tooth or a segment of teeth, overlap
the opposing maxillary teeth labially or buccally on their location in the arch, this
situation can be defined as a crossbite.[[3]]
Literature Review
Dental crossbite involves localized tipping of a tooth or teeth and does not involve
basal bone.[[4]] Patients with anterior dental crossbite will show a normal anterior-posterior skeletal
relationship with a smooth path of mandibular closure into an Angle Class I relationship
and coincident centric occlusion (CO) and centric relation (CR).[[4]] The incidence of anterior dental crossbite showed 4–5% and mostly occurs during
the early mixed dentition phase.[[5]],[[6]] The cause of anterior dental crossbite was reported to be multifactorial and includes
the following: maxillary anterior incisors have a lingual-erupted path, displacement
of the permanent tooth germ of incisors due to trauma to the primary incisors, over–retained
of necrotic or pulpless deciduous tooth, anterior supernumerary teeth, inadequate
arch length and crowding in incisors, and habit of biting the upper lip.[[5]],[[6]],[[7]]
When an anterior crossbite is detected in a mixed dentition, the orthodontist should
realize that the malocclusion may adversely affect the forward maxillary alveolar
growth and further complicate the crowding of the maxillary anterior teeth.[[3]] Therefore, anterior crossbite should be corrected as soon as it discovered.[[2]],[[3]],[[8]]
As an important part of the diagnosis, the orthodontist must check the presence or
absence of anterior shift from CR to CO during mandibular closure to differentiate
between pseudo and true Class III malocclusion[[3]] and to distinguish the dental or skeletal origin of anterior crossbite.[[9]],[[10]],[[11]] Furthermore, the overbite has an effect on the treatment and retention of the teeth
in crossbite. A posterior bite block is needed for the treatment of an anterior crossbite
associated with a deep anterior overbite.[[3]] To allow lingually positioned maxillary incisors move anteriorly without occlusal
interferences from the lower incisors.[[3]] In this case report, we represent the management of an adult patient with anterior
dental crossbite malocclusion under skeletal Class I background.
Treatment Plan
As the patient had skeletal and dental Class I, a camouflage treatment was our choice.
Because the upper canines extracted early, the upper first premolars well replaced
the upper canines. The anterior crossbite and the lower crowding will be corrected
by the extraction of the lower first premolars and retracted the canines and lower
incisors by using multilooping retraction arch with maximum anchorage in the lower
jaw (lingual holding arch).
Methods
As the upper arch was well aligned, the treatment postponed in it and started in the
lower arch by bonding stainless steel brackets (0.018). The extraction of the lower
first premolars was done, followed by leveling and alignment which achieved within
about 3 months. The arch sequence used was (nickel–titanium alloy) 0.014, 0.016, and
0.018, followed by stainless steel archwires 0.018, 0.016 × 0.022, 0.017 × 0.025,
then the retraction of the canines was done until the Class I occlusion achieved between
the upper first premolars and lower canines, since the upper canines were extracted
early.
The correction of anterior crossbite was started using retraction looping arch (ball
loop). The vertical loops were placed between the lower anterior teeth and lower canines
(mesial to the lower canines), after opening the overbite by placing a composite block
on the occlusal surfaces of the lower first molars. 17 × 25 SS wire was used as a
finishing wire. Appointments were given every 5 weeks for checking the progress of
the treatment, activation of the appliance, and changing the archwire if required.
Results
The correction of the crossbite was achieved successfully within 18 months. Orthognatic
profile [[Figure 3]], normal overbite and overjet [[Figure 4]] were accomplished at the end of the treatment. There was no need for retention
after the treatment as anterior crossbite as it self-retained. 3 months and 6 months'
appointments were arranged for following the case and taking more photographs for
documentations.
Figure 1: Frontal and lateral view after treatment, note the improvement of the patient profile
Figure 4: Normal overjet and overbite with Class I molars and upper first premolars occlude
in Class I with the lower canines
Discussion
As the patient was an adult and has Class I malocclusion with a history of early extraction
of the upper canines, a fixed appliance treatment was the choice to achieve bodily
movement and avoid the great labial inclination of the upper incisors.[[3]],[[9]] The extraction of the lower first premolars was done to create enough space for
the lower incisors to aligned and retracted and also to accommodate the early missing
of the upper canines.[[4]],[[8]] The lingual arch was used to reinforce the anchorage,[[1]] and segmental retraction of the canines with light force helps in maintaining about
75% of extracted space for the retraction of the canines.[[1]],[[3]] Furthermore, the patient with about an average angle case this may help in reinforce
the anchorage and reduce the tendency of posterior segment from mesial movement.[[12]] This may coincide with Mitchell[[12]] who explained that the patient with reduced vertical dimension has less anchorage
loss because of the relative strength of the facial muscles. In the next visit and
by achieving Class I relation between the upper first premolars and the lower canines,
the lower anterior retracted with multilooped arch 16 SS × 22 SS with light retraction
force until normal overjet and overbite were achieved [[Figure 4]] and the profile had been enhanced [[Figure 3]].
Conclusion
Anterior dental crossbite in adult can be treated by various and contemporary methods
but still the use of retraction multilooping arch with light retraction forces is
considered effective and a less aggressive method of correction the bite and achieve
normal overjet and overbite.
