++
The American Association of Orthodontists (AAO) recommends that
all children be examined by no later than age 7.13 The
rationale for this is that the posterior occlusion is established
when the first molar teeth erupt, allowing assessment of the anteroposterior
and transverse relationships of the occlusion and identifying the presence
of any functional mandibular shift. The incisor teeth have begun
to erupt, and problems can be detected such as crowding, anterior
crossbites, posterior crossbites, open bites, oral habits, maxillary protrusion,
and some facial asymmetries (eTable 376.2).
For some, a timely evaluation will
lead to significant treatment benefits; for most, the principal
immediate benefit is a parent’s peace of mind. The pediatrician
who makes timely referrals is rightly regarded as informed, caring,
and concerned for the patient’s total well-being. Recognition
and basic management of these disorders is summarized briefly in
the sections that follow. More detailed guidance is provided on
the textbook DVD.
++
For those patients who have clear indications for early intervention,
early treatment presents the opportunity to
++
Crowding is one of the most prevalent components of malocclusion
in the mixed, adolescent, and permanent dentitions, affecting as
many as 40% of children ages 6 to 11 and 85% of
children ages 12 to 17.11 The etiology of crowding
is multifactorial and may include tooth-size/jaw-size discrepancies,
loss of arch length (due to interproximal caries or the premature
loss of primary teeth), ectopic eruption of teeth, or the presence
of supernumerary teeth.3,10,11 It is important
to emphasize that the premature loss of primary teeth, particularly
molars, may require the use of fixed or removable space maintainers
to prevent the development of unnecessary crowding or the exacerbation
of existing crowding.14 Management of the space
within the dental arches is the prime responsibility of the pediatric
dentist and orthodontist. Failure to do so may result in the need
to extract permanent teeth, difficulty in maintaining adequate oral
hygiene, or the need for more complicated and lengthy orthodontic
treatment (Fig. 376-5). A healthy
and complete primary dentition plays an essential role in maintaining
the space needed for the permanent teeth. A patient with prematurely
lost, missing, or decayed teeth should be referred to a pediatric
dentist or orthodontist for management as soon as the problem is
detected. 3
++
++
Managing the crowded dentition requires examination and analysis
of the space needed to accommodate the teeth, the space available,
the occlusion, the profile, the periodontal health, and the oral
hygiene status. It must also account for future growth and development
of the jaws, the teeth, and the dental arches. Treatment modalities
range from space maintenance in the mixed dentition to comprehensive
orthodontic treatment involving the extraction of several permanent
teeth.15 Pediatricians should encourage their patients
with crowded dentitions to be evaluated while in the mixed dentition
stage in order to preserve the choice between extraction and nonextraction
treatment. Delayed evaluation leads to a need for extraction in
the majority of cases.10,14,15
++
An anterior crossbite is defined as the lingual
position of one or more maxillary anterior teeth in relationship
with the corresponding mandibular anterior teeth (Fig.
376-6). The etiology of anterior crossbite malocclusions is
summarized in eTable 376.3. Anterior crossbites
may be differentiated into dental, functional, and skeletal crossbites,
with any combination possible. Correcting anterior crossbites in
a timely manner may be important to prevent untoward growth of the
skeletal and dentoalveolar components of the craniofacial complex. Treatment may also be helpful
in preventing attrition of the incisors and canines, in avoiding
periodontal problems around ectopic incisors, in alleviating functional
posterior crossbites that can develop from cuspal interferences
caused by the anterior crossbite, in preventing habits such as bruxism,
and in reestablishing proper muscle balance. Simple recognition
of an anterior crossbite by the pediatrician is enough to justify
referral to the pediatric dentist or orthodontist. The etiology
of anterior crossbite malocclusions is summarized in eTable
376.3.
++
++
++
Diagnosis of a skeletal or functional anterior crossbite may
be accomplished by viewing the patient in profile. The child will
usually have a concave profile, with the base of the nose deficient
in relation to the chin point. It is important for the practitioner
to know that the timing of treatment for a skeletal anterior crossbite
malocclusion may be critical. Studies have shown the potential for
interceptive orthodontic treatment to be effective in correcting
this malocclusion in as many as 66% to 75% of
the cases if treatment is undertaken before the age of 10.16,17 In
the author’s opinion, the pediatrician should question
any treatment, or lack thereof, that does not consider this opportunity,
because once the child matures, the treatments may become more complicated and
less desirable. Similarly, it must be understood that some of these
malocclusions cannot be successfully treated without a combined
orthodontic and surgical approach and that careful diagnosis and
treatment planning is essential in all of these cases.18
++
Treatment often requires a combined orthodontic and surgical
approach.18 The modality of the chosen treatment
depends on whether the child is in the primary, mixed, or permanent
dentition and if a single tooth or several teeth are involved. A
child presenting in the primary dentition (usually age 5 or less)
typically has a single incisor tooth in crossbite and may also have
an anterior functional shift of the mandible. In the younger child,
various treatment options are available, including reassurance and
periodic monitoring; occlusal grinding of the tooth responsible
for the interference; appropriately timed extraction of the offending
tooth if it is close to exfoliation; and use of a removable or a
fixed appliance, depending on the child’s level of compliance.
++
Treatment regimes for the older child presenting in the mixed
dentition (usually 6–11 years of age) include removable
or fixed appliances and orthopedic devices. Appliance therapy for
correcting an anterior crossbite may include expansion of the maxillary
arch; this creates room for alignment of a palatally displaced tooth.
Proven methods for correcting anterior crossbite malocclusions in
young children are using a removable maxillary appliance with auxiliary
springs or screws or using a removable mandibular appliance with
a labial bow for anterior tooth retraction. Alternatively, in less
compliant children, partial fixed appliances (2 molar bands and
4 bonded incisor brackets) may be used to tip the maxillary incisors
forward. Orthopedic treatment in the form of extraoral traction
can be applied to children with maxillary retrognathia in order
to protract the maxillary skeletal and dentoalveolar complex forward.
++
A posterior crossbite malocclusion is defined
as the abnormal buccolingual relationship between two or more maxillary and
mandibular posterior teeth and has a reported prevalence of 7.7% to
17.6% in preadolescent children.19,20 The
most common type of posterior crossbite is when the buccal cusps
of the maxillary molars occlude palatally to the buccal cusps of
the mandibular molars, unilaterally or bilaterally (Fig.
376-7). Much less common is the buccal or “Brodie” crossbite,
which is when the palatal cusps of the maxillary molars occlude
to the outside of the buccal cusps of the mandibular molars. Posterior
crossbites may result from a dental transverse deficiency, the tipping
of teeth, a skeletal transverse deficiency, sagittal discrepancies
between the jaws, functional shifting of the mandible, or any combination
of these factors.
++
++
Dentoalveolar crossbites are usually due to insufficient arch
length or the prolonged retention of deciduous teeth, both of which
can cause ectopic eruption of a tooth or teeth into crossbite. A
skeletal crossbite is related to discrepancies between the transverse
dimensions of the maxilla and mandible and could be due to a narrow
maxilla, a wide mandible, or a combination of both. Since the type
of treatment required for correction will depend mainly upon the
origin of the problem, determining the dental or skeletal component
of posterior crossbite represents the first step in treatment planning.
++
The pediatrician should be aware of the different types of posterior
crossbites previously described and should understand that treatment
is available to correct each of these problems. Of particular importance is recognizing that posterior crossbites accompanied
by a functional shift of the mandible should be treated
as early as possible. These comprise between 67% and 79% of
unilateral crossbites found in the growing child, making them the
most common type found in this group.20,21 The
pediatrician may determine if there is a functional shift of the
mandible by assessing the position of the chin from the posterosuperior
view when the teeth are in occlusion and when they are not. When this
condition is treated at the appropriate time, compensatory growth
of the mandible may eliminate any positional and skeletal asymmetries
present and may create optimum conditions for normal craniofacial growth
and development. If the condition is left untreated, asymmetric
growth of the mandible may result in permanent skeletal asymmetry
that could have been avoided.22,23
++
Three points should be considered during the clinical differential
diagnosis of dental versus skeletal transverse deficiency:
++
1. The angulations (buccopalatal) of the posterior
teeth. If the posterior teeth are of normal angulations
in the presence of a unilateral or bilateral posterior crossbite,
then a skeletal discrepancy is present. Consequently, orthopedic
correction using a rapid or slow maxillary expander that may be
bonded or banded should be considered. However, if the posterior
teeth are improperly angulated, the problem is dental in origin
and treatment should aim to correct the crossbite by dental uprighting,
which will eliminate the crossbite. The exposure and analysis of
a frontal (posteroanterior) cephalometric radiograph may be required
to determine these angulations and to accurately determine the presence
and magnitude of any skeletal discrepancy between the jaws.
2. The severity of the crossbite. A posterior
crossbite that is bilateral, that involves multiple teeth, and that
has an increased maxillomandibular arch width discrepancy usually
reflects an underlying skeletal problem.
3. The morphology of the palatal vault. A deep
and V-shaped palate is indicative of a skeletal deficiency.
++
Treatment differs substantially, depending on the underlying
cause of the malocclusion. Skeletal crossbites, which usually result
from a narrow maxilla but occasionally from an excessively wide
mandible, are generally treated by heavy forces to open the midpalatal
suture and make the maxilla wider. Dental crossbites are treated
by moving the teeth with lighter forces. Although this is a correct
concept for adolescents in the late-mixed and early permanent dentition,
the lesser interdigitation of the midpalatal suture in the early
mixed dentition means that even modest forces will cause both skeletal
and dental changes.
++
Posterior crossbites in children often appear to be unilateral
but on close examination are usually found to result from bilateral
constriction of the maxillary arch and a shift of the mandible to
one side on closure. More severe constriction may result in a bilateral
crossbite without a mandibular shift; occasionally, a true unilateral
posterior crossbite from an intra-arch or jaw asymmetry will be
noted.
+++
Open Bite and Oral Habits
++
An open-bite malocclusion is defined as the lack of normal vertical
overlap (overbite) between the maxillary and mandibular incisors
in the case of an anterior open bite (Fig. 376-8)
or between the maxillary and mandibular posterior teeth in the case
of a posterior or lateral open bite.3,24 Dental
open bites are most common and are restricted to malposition of
the teeth (proclined maxillary incisors, retroclined mandibular
incisors, infraocclusion) and deformation of the surrounding alveolar bone;
skeletal open bites are characterized by problems with the underlying
growth patterns and the relative positions of the maxilla and the
mandible. A patient presenting with a dental open-bite malocclusion will
have relatively normal skeletal components, whereas in skeletal
open-bite malocclusions, a discrepancy in the cranial base, maxilla,
or mandible may be observed. Characteristics observed in skeletal
open bites include a distal condylar inclination, short ramus height,
antegonial notching, an obtuse gonial angle, excessive maxillary
height, a straight mandibular canal, a thin and long symphysis,
excessive anterior facial height, short posterior facial height,
an anteriorly tipped-up palatal plane, a steep mandibular plane,
divergent occlusal planes, a tendency toward a Class II malocclusion,
mandibular deficiency, a narrow maxilla, and a posterior crossbite.25,26
++
++
Open bites are often found in conjunction with sagittal dysplasias
of the jaws (such as overbite and underbite types of malocclusions)27,28 but
may also present alone. They are more commonly observed in the younger,
mixed dentition age group.29 The literature has
reported that African Americans have a greater incidence (6.6%)
of open-bite malocclusion than do Caucasians (2.9%) or
Hispanics (2.1%).30 The highest reported
incidence of anterior open-bite malocclusion is found in mentally
retarded and in children with Down syndrome.31
++
Vertical growth discrepancies have been postulated as causative factors in
skeletally based open-bite malocclusions. These involve the direction,
pattern, and rotation of mandibular growth, as well as vertical underdevelopment
of the middle cranial fossa (producing an elevation of the glenoid
fossa) and inadequate alveolar growth in the anterior portion of
the maxilla.26,32-35 Transitional dental open-bite
malocclusions occur during the mixed dentition stage as the deciduous
teeth exfoliate and the permanent teeth erupt, with self-correction
reported in over 80% of patients.29 Noninherited
factors that result in open bites include trauma to the condyles,
muscle dysfunction, pathological disturbances of dental development
encompassing the presence of supernumerary teeth, ankylosis, root
dilacerations, cysts, and prolonged retention of deciduous teeth.36-38
++
Chronic oral habits, such as non-nutritive sucking, tongue thrusting, and
mouth breathing, are likely to be causative or contributing factors
in the majority of open-bite malocclusions the pediatrician will encounter.
Prolonged digit and pacifier sucking are the prime offenders in
this category, while tongue thrusting is usually an adaptation to
the open bite already present. These habits disturb
the normal equilibrium of pressures and forces that exist between
the orofacial musculature and the dentition, directly resulting
in the open bite seen.39
++
During the primary dentition and early mixed dentition years, many children engage
in finger and pacifier sucking. Although it is possible that a prolonged
and intense habit may deform the alveolus and dentition during the
primary dentition years, much of the effect is on eruption of the
permanent anterior teeth. The effect of such a habit on the hard
and soft tissues depends on its frequency (hours/day) and duration
(months/years). While most children will discontinue sucking
habits by the age of 3 or 4 years, some may continue. If the finger
sucking habit ceases prior to the eruption of the permanent incisors, any
dental changes resulting from the habit may resolve spontaneously.
However, persistent sucking habits extending into the mixed and
permanent dentition age groups may result in an anterior open-bite malocclusion
that requires intervention to resolve.
++
The etiological relationship of tongue thrusting and open-bite malocclusion is not completely
clear. While some of the literature suggests that tongue thrusting
may be a direct cause of anterior open bite, most authors believe
that it is just an adaptation used to achieve a good oral seal during
swallowing, with the open bite actually caused by a sucking habit
or the result of skeletal factors. Respiratory patterns and airway
obstructions have also been implicated in the etiology of open-bite
malocclusions, possibly from a resultant change secondary to abnormal
resting head and jaw posture made necessary by the compromised airway.
Although experimental studies in primates have demonstrated a relationship
between complete nasal obstruction and the development of open bite,
other investigations have failed to demonstrate a significant clinical
correlation between airway obstruction and the development of open-bite malocclusion.
++
Open-bite malocclusion therapy in the mixed and early permanent dentition
is directed toward addressing obvious etiological factors (eg, removing
pathological obstructions of eruption of the anterior teeth and
controlling of oral habits). Skeletal discrepancies should be treated
through intervention with ongoing growth, focusing on reducing or
redirecting the vertical skeletal growth and controlling vertical
dentoalveolar development by impeding molar eruption or extruding
anterior teeth. Headgear has been traditionally the preferred appliance
for treating high-angle open-bite patients, whereas functional appliances such
as the Active Vertical Corrector appliance, the Herbst appliance,
or the Frankel function regulator (FR-4) may be useful in treating
patients presenting with an open bite and concomitant mandibular deficiency.
Posterior bite blocks are used to intrude or control eruption of
the posterior teeth and to encourage subsequent bite closing through
mandibular autorotation.
++
Some have considered non-nutritive sucking to be a symptom of
emotional disturbance. However, the majority of the literature suggests
that most oral habits are simply learned behaviors and that treating
a habit causing a malocclusion in a child who is mature enough to
understand the process will not result in any serious symptom substitution.40 A
straightforward discussion with the parent, child, and dentist and
counseling the child on the detrimental effects of the habit should
be the first attempt at treatment. A reward system that encourages the
child to stop the habit may also prove to be effective. Beyond this,
physical reminders such as a bandage on the offending finger are
the next level of intervention to be considered. These include placing
a finger bandage, an elbow splint, a sock, or a glove over the hand. Interceptive
therapy using removable or fixed appliances, such as a
palatal crib, is the preferred treatment if the malocclusion resulting
from the habit warrants the expense and effort required.41 With
the use of any appliance, it is imperative that the child be informed
that the appliance is meant only as a reminder to assist the child
in breaking the habit, not as a punitive measure. A fixed palatal
crib (eFig. 376.5) is an effective
measure in arresting a persistent digit-sucking habit42 and
serves to restrain the tongue, therefore allowing for some degree
of self-correction of the open bite to occur. An uncontrolled habit
of sufficient frequency, duration, and intensity may maintain or
exacerbate the open-bite malocclusion and significantly worsen the
prognosis for successful orthodontic treatment.
++
++
Overjet is the term used to describe the horizontal
relationship of the maxillary and mandibular incisor teeth. The
incisors are normally in contact, with the maxillary teeth forward
of the mandibular teeth by the thickness of their incisal edges
(normal overjet is 1–2 mm). Maxillary protrusion is defined
as excessive overjet (5 mm or more) and is found in approximately
23% of children, 15% of adolescents, and 13% of
adults43 (Fig. 376-9).
++
++
Maxillary protrusion may represent a normal developmental period,
as seen during the transition from the primary to the mixed dentition
or from the mixed to the permanent dentition, but may also be related
to an underlying dental or skeletal malocclusion. The key components
of this type of malocclusion can include mandibular skeletal retrusion;
maxillary dental protrusion; excess vertical skeletal development;
and, less frequently, mandibular dental retrusion and maxillary
skeletal protrusion.44 The most common causes of
increased maxillary incisor protrusion are the presence of oral
habits (such as digit sucking or tongue thrusting), dental crowding,
ectopic eruption, and discrepancies between the positions of the
jaws.
++
Children with maxillary protrusion are at increased risk for
injuries to their maxillary anterior teeth.45 Treatment
of excessive overjet should be considered for this reason alone
but may also serve to improve the child’s self-image. Studies
indicate, however, that children treated in this manner will most
often require a second phase of orthodontic treatment and that one-stage
treatment at a later time will provide a similar outcome in most
cases.46 Overjet is the leading reason why parents
seek orthodontic treatment for their children.47 Additionally,
addressing an increased overjet can serve to maintain the periodontal
health of the anterior gingiva and prevent further development of
abnormal soft tissue function and underlying skeletal discrepancies.
++
The approach to treating maxillary protrusion in children and
adolescents is largely determined by the underlying etiology of
the malocclusion. If a skeletal discrepancy exists, treatment options
include extraoral traction (headgear), the use of a functional
appliance, or orthognathic surgery in the case of severe problems.
Therapeutic techniques used to address maxillary protrusion of dental
etiology include braces, removable appliances, the distalization
of the maxillary teeth, or the extraction of teeth.
++
The authors wish to thank Drs. Murray Dock and Robert L. Creedon
for their contribution to this chapter. They were the authors of
this chapter in the previous edition of this text, and their work
is carried over largely intact for sections of this edition.