Download Orthodontic treatment of anterior open bite: a review article—is

Oral Maxillofac Surg (2014) 18:271–277
DOI 10.1007/s10006-013-0430-5
REVIEW ARTICLE
Orthodontic treatment of anterior open bite: a review
article—is surgery always necessary?
Isabelle Reichert & Philipp Figel & Lindsay Winchester
Received: 14 May 2013 / Accepted: 29 July 2013 / Published online: 16 August 2013
# Springer-Verlag Berlin Heidelberg 2013
Abstract
Introduction Anterior open bite cases are very difficult
to treat satisfactorily because of their multifactorial
aetiology and their very high relapse rate. Dependent
on the origin of the anterior open bite malocclusion
and the patient’s age, there are several treatment possibilities ranging from deterrent appliances, high-pull
headgear, fixed appliances with and without extractions to
orthognathic surgery, and skeletal anchorage with miniplates
or miniscrews.
Methods The gold standard treatment of skeletal anterior open
bite cases is the combined approach of orthodontic treatment
with fixed appliances and orthognathic surgery. In recent
years, temporary anchorage devices (TAD) have been developed to correct anterior open bites orthodontically. With the
introduction of TAD as an effective treatment modality,
orthognathic surgery may be avoidable in selected anterior
open bite cases.
Conclusion This is a relatively new technique and to date
there remains a lack of evidence of long-term stability of
anterior open bite closure with TAD.
Keywords Anterior open bite . TAD . Orthognathic . Skeletal
anchorage . Relapse
I. Reichert (*) : L. Winchester
Orthodontic Department, Queen Victoria Hospital NHS Foundation
Trust, Holtye Road, East Grinstead, West Sussex RH19 3DZ, UK
e-mail: [email protected]
P. Figel
School of Oral and Dental Sciences, Bristol Dental Hospital and
School, University of Bristol, Lower Maudlin Street, Bristol BS1
2LY, UK
Introduction
The anterior open bite (AOB) malocclusion is one of the most
challenging malocclusions to treat due to the high frequency
of relapse [1–6]. It is defined as no vertical overlap of the
incisors when buccal segment teeth are in occlusion. This
paper aims to review and summarize the different orthodontic
treatment modalities that can be used for the management of
AOB as an alternative to surgery, together with the evidence
for their effectiveness.
The early 1960s to the mid-1970s are called the “era of
tongue thrusts,” because the malocclusion was often thought
to be caused by tongue thrust [6]. Before the 1970s, the
orthodontic treatment mainly consisted of dentoalveolar
changes and/or modification of habits [7].
AOB has a multifactorial aetiology including skeletal, dental, respiratory, neurologic, and habitual components [1, 8]. It
can be broadly described as being skeletal or dental in origin
[9].
A high-angle skeletal pattern with increased Frankfort
Mandibular Plane Angle can lead to an AOB when the vertical
component of growth disproportionally exceeds the horizontal
component of growth. Labial tooth eruption cannot compensate for the increase in inter-occlusal distance with, in severe
cases, only the posterior molars in occlusion. Patients with an
AOB may have some or all of the following cephalometric
features: pronounced ante-gonial notching, recessive chin,
reduced inter-incisal angle, reduced inter-molar angle, and
increased lower anterior facial height. It is believed that soft
tissues also play a role in AOB. Incompetent lips might lead to
a tongue thrust, to make an oral seal while swallowing,
influencing the dentoalveolar position of the anterior segments
by intruding them. Digit sucking often results in an AOB, by
preventing vertical incisor eruption, with associated posterior
cross bites caused by increased cheek pressure and lowered
tongue position, resulting in narrowing of the arch. Prolonged
mouth breathing due to increased tonsillar or adenoidal
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obstruction may be a contributory factor which can cause
increased vertical growth [8].
The indications for treatment are generally aesthetic and
functional improvement. Patients with a severe AOB often
have difficulties incising food as well as speech problems
including lisps. Closure of an AOB usually helps with eating
but there is only little evidence that it might help with speech
[8, 9].
The literature shows a variety of treatment possibilities to
close AOB, depending on respective diagnoses. High-pull
Headgear, chin cups, various types of bite blocks, functional
appliances, fixed appliances with or without extractions, and
multi-loop edgewise archwires are some examples of the
treatment modalities [10].
Difinitive treatment in cases of skeletal aetiology frequently involves a combined approach of orthodontic treatment
with fixed appliances and orthognathic surgery. In the majority of cases, the surgery includes a Le Fort I osteotomy with
posterior maxillary impaction or bimaxillary osteotomy [8, 9].
Orthognathic surgery for the management of AOB can be
notoriously unstable. Several studies have compared different
orthognathic treatment to close an AOB and their relapse
rates. In 2000, Proffit et al. found that maxillary impaction
was less prone to relapse (7 % overbite decrease) than two jaw
surgery (12 % overbite decrease) [11].
Teittinen et al. also examined the relapse rate of patients with
previous maxillary impaction only compared with patients with
maxillary impaction and mandibular counterclockwise rotation
to close AOB. All of the patients who had a maxillary impaction only showed a positive overbite 3.5 years after treatment
but in three cases with bimaxillary surgery the open bite recurred. A vertical relapse of the maxilla was noticed in both
groups (one and two jaw surgery); in the bimaxillary group, the
changes were statistically significant [12].
It may also be possible to close an AOB surgically by
counter clockwise rotation of the mandible. This has been
considered by many as unpredictable due to the risk of lengthening the pterygomasserteric sling. Frey et al. noticed greater
relapses when the counter clockwise rotation of the mandible
was used as operation method [13]. Bisase et al. reported that
the closure of AOB by mandibular counter clockwise rotation
are at least as stable as AOB closed by maxillary impaction
and recommended this method in class II cases with retrusive
mandible and chin [5]. Van Sickels reviewed the literature on
closure of AOB with counter clockwise movement of the
mandible, presented three cases with variation of stability,
and concluded that counter clockwise rotation of the mandible
should be used with caution. He noted that larger and more
rigid plates and screws can help to prevent the early stability
but there is no doubt that skeletal AOB are prone to relapse
independent of the applied surgical method [14].
In the last few years, as an alternative to treating a skeletal
AOB by orthognathic surgery, skeletal anchorage devises
Oral Maxillofac Surg (2014) 18:271–277
have been developed. Skeletal anchorage is being used for
molar intrusion to correct an AOB [2–4, 15–21].
Deterrent appliances
In young patients where the AOB is related to a digit sucking
habit the open bite closes naturally after stopping the habit.
Passive orthodontic appliances such as the Hayrake appliance
(Fig. 1) can help in stopping thumb-sucking habit and allow
spontaneous improvement.
High-pull headgear
The use of a high-pull headgear (Fig. 2) is a common approach
for the management of AOB treatment, intruding upper molars that are considered to be extruded and therefore causing
the AOB [6]. Some authors also reported some vertical control
by minimizing the clockwise rotation or even resulting in a
counterclockwise rotation of the mandible [22, 23]. It is often
combined with functional and fixed appliances.
Posterior bite blocks
Posterior bite blocks are usually made of acrylic and fit
between the maxillary and mandibular teeth. They can be
spring loaded or provided with magnets and are usually used
in the early treatment of AOB cases. By impeding eruption of
the posterior teeth, this allows an upward and forward autorotation of the mandible [9, 24, 25]. Maxillary intrusion splints
which cover the whole of the maxillary dentition are also used
with high-pull headgear in cases where it is intended to intrude
the whole of the maxillary dentition, such as gummy smile
cases, which have a degree of vertical maxillary excess. Iscan
et al. conducted a study in which they compared the effectiveness of passive posterior bite blocks of two different heights (5
and 10 mm), with an untreated control group of AOB cases. It
was revealed that the downward and backward rotation of the
mandible continued in the control group increasing lower face
height significantly, whereas in the treated groups the mandible rotated upward and forward and produced a positive
overbite [25].
Functional appliances
Removable functional appliances combined with high-pull
headgear can be used in growing patients where the AOB is
associated with a class II malocclusion. This combination
helps to correct the anteroposterior discrepancy while controlling the vertical dimension [9].
In our practice, we usually use a Clark Twinblock as the
functional appliance of choice combined with high-pull headgear for the management of AOB with a skeletal II pattern.
This removable functional appliance has two bite blocks,
Oral Maxillofac Surg (2014) 18:271–277
273
Fig. 1 a An 11-year-old female
patient with a digit sucking
associated AOB. b Patient with
fitted Hayrake appliance
(deterrent appliance). c Occlusal
changes 3 months after wearing
Hayrake appliance
upper and lower, which work together to posture the lower jaw
forward. In Class II AOB cases where the Twinblock is used
in combination with high-pull headgear the upper appliance
has an expansion screw to widen the arch and always has
tubes positioned occlusally between premolars and molars to
fit the headgear (Fig. 3).
Fig. 2 Patient wearing high-pull headgear
The open bite-bionator is a removable appliance with posterior bite blocks to inhibit the extrusion of the posterior teeth.
Fig. 3 a Patient with Clark Twinblock with flying tubes to insert a
Headgear. b Patient wearing Clark Twinblock with high-pull headgear
274
Acrylic portion extends from the lower lingual part into the upper
region as a lingual shield; the labial bow is positioned at the
height of correct lip closure. Defraia et al. examined 20 patients
with a high angle skeletal relationship treated with the bitebionator and compared the MPA to a nontreated control group.
The treated group showed a significant smaller palatal planemandibular plane angle (−1.9°) and greater overbite (+1.5 mm).
He concludes that early treatment with the open-bite bionator
produces an improvement of intermaxillary divergences [26].
The Fränkel 4 has been advocated in cases where the open
bite occurs partly from faulty postural activity of the orofacial
musculature. It is a removable functional appliance which
works by allowing vertical eruption of upper and lower incisors and retraction of the upper incisors. Some authors have
established that the wear of the Frankel can change the mandibular rotation from downward and backward to upwards
and forwards. A randomized clinical trial conducted by Erbay
et al. evaluates the effects of Fränkel’s function regulator
appliance on the treatment of Angle Class I skeletal AOB
malocclusion, with results indicating that a spontaneous
downward and backward growth direction of the mandible,
that were observed in the control group, could be changed to a
upward and forward direction by Fränkel 4 therapy [27].
Vertical chincup
This appliance is occasionally used in growing patients to try
to reduce excessive vertical growth by redirecting the condylar growth, but has fallen out of favour in recent years due to
poor evidence of its efficacy.
In 1978 Pearson treated twenty growing patients with
backward rotational tendencies and AOB by extracting four
first premolars, wearing a vertical pull chin cup for at least
12 hours a day while waiting for the remaining teeth to erupt.
The AOB were all closed and the mandibular plane angles
reduced an average 3.9° [28].
Torres et al. [29] investigated the dentoalveolar and soft
tissue changes produced by a removable appliance associated
with high-pull chin cup therapy in children with an Angle
Class I AOB. They compared the outcome of patients treated
with a control group and the results showed no significant
differences in the level of molar eruption or in lower anterior
face height, which suggests that the vertical control expected
from the chin cup therapy did not occur [29].
Oral Maxillofac Surg (2014) 18:271–277
Fixed appliances with anterior box-elastics induce the extrusion of the anterior incisors, which is only helpful when the
incisors are not already extruded by natural compensation [8]
and is often unstable. The additional use of straight-pull Headgear to distalize the molars is contraindicated as it opens the
bite, by inducing molar extrusion.
Class II or III elastics should be used with caution because
of the undesired side effect of molar extrusion [9]. Schudy
elastics (elastics with an anterior vertical component) however
have been reported as helpful in these cases as they allow an
additional anterior extrusion component of force. The
retroclination of proclined upper and lower incisors closes
the AOB [30].The stability of AOB correction by orthodontic
fixed appliances will depend on the adaptation of the soft
tissues to the new dental arrangement of the teeth. Extractions
of premolars and orthodontic space closure with fixed appliances are a possible treatment option of AOB correction. The
mesial movement of the molar teeth can result in a reduction
of the mandibular plane angle with a resultant closure in the
AOB and the incisors can be retracted, resulting in uprighting
and relative extrusion [30] (Fig. 4).
A study by Lopez-Gavito et al. dealt with the stability of
open bite cases treated with fixed appliances, headgear, and
elastics. Cephalometric radiographs of 41 patients with at least
3 mm of open bite were evaluated at three different points in
time, pretreatment, immediately post-treatment, and 10 years
post-retention. They found that 35 % of the patients had an
open bite of 3 mm or more, whereas 65 % showed relatively
stable results [31].
Another study by Zuroff et al. increased the sample size (64
patients) and differentiated between three groups, based on the
amount of pretreatment overbite. A contact group (incisal
overlap and incisal contact), an overlap group (incisal overlap
and no incisal contact), and the open bite group (no incisal
overlap). At ten years post-retention, 60 % of the open bite
subjects did not have incisor contact. On the other hand, in the
whole sample, the largest vertical relapse was 2.4 mm, and no
one had negative incisor overlap [10].
Fixed appliances
AOB can also be closed by using upper and lower fixed
appliances with vertical intermaxillary elastics to extrude the
anterior incisors. In addition to the fixed appliance, a
transpalatal arch and a high pull headgear to intrude the upper
molars can be used. Fixed appliances alone should be used in
cases where the open bite is of dental but not skeletal aetiology.
Fig. 4 Patient wearing fixed appliances and Schudy elastics
Oral Maxillofac Surg (2014) 18:271–277
Multi-loop Edgewise Archwire technique
Kim et al. described the use of the Multi-loop Edgewise
Archwire technique for AOB closure treatment [6]. They used
a 16×22 stainless steel edgewise ideal archwire in an edgewise
bracket system, with no prescription for torque, angulation or tip.
Vertical and horizontal control and decreasing the load and
deflection rate were achieved through bending loops into the
archwires. The loops are L-shaped and are positioned between
every interbracket distance distal to the lateral incisors (five loops
in each quadrant). This appliance works by uprighting the molars
and extruding the anterior teeth subsequent to the alteration of
the occlusal plane. Heavy intermaxillary elastics are used to close
the AOB by extruding the anterior segments. The disadvantage
of this technique is that the majority of correction was realized by
the extrusion of the anterior teeth, not by the intrusion of molars.
The extrusion of anterior teeth is prone to relapse [16].
Temporary anchorage devices
In recent years, titanium miniplates and miniscrews have been
used as skeletal anchors to correct AOB orthodontically
(Fig. 5). The use of skeletal anchorage offers more treatment
options for orthodontists and this has a particular application
in the correction of AOB [32]. Some workers claim that the
use of skeletal anchors can obviate the need for orthognathic
surgery in the management of AOB cases.
The studies of Umemori et al. [33] demonstrated the effective intrusion of mandibular molars by using titanium
miniplates for anchorage. In two severe AOB cases, two titanium L-shaped miniplates were fixed on each side at the buccal
cortical bone around the apical regions of the lower first and
second molars. By using elastic threads as orthodontic force,
the lower molars were intruded and open bite was significantly
improved. One month after the fixation of the plates force
application was started. Upper and lower teeth were bonded
with a straight wire fixed appliance. Intrusion was completed
after 5 months, and after 18 months, the fixed appliance and the
Fig. 5 TAD in place (between LL6 and LL7) to intrude molars
275
miniplates were removed. Class I occlusion was achieved with
a normal overbite and overjet and the mandibular plane angle
declined from 41° to 39.5°and 41.9° to 37.7°, respectively,
mainly due to a decreased posterior vertical dimension. The
lower molars were intruded 3.5 and 5 mm, respectively, and the
occlusal plane was counterclockwise rotated by 4°, 2°, and 3,
1°, respectively. The author concludes that implants as anchorage to simplify the orthodontic treatment can be successfully
used to intrude the molars in AOB cases. Nevertheless, there is
no evidence in long-term follow-up controlled randomized
studies that confirm these theses.
Erverdi et al. [20] proposed the zygomatic buttress area as
an anchorage site for maxillary molar intrusion and reported
the closure of AOB. In his case report from 2006, an L-shaped
implant was fixed with three bone screws in the zygomatic
buttress area with the tip exposed and used for intrusive force
application. The orthodontic appliance consisted of two acrylic bite blocks connected with two palatal arches and wire
attachments on each buccal side, which were used for force
application. The force application commenced 7 days after
implant insertion. Two 9.0-mm NiTi coil springs were placed
bilaterally between the tip of the implant and the outer wire
creating an intrusive force of 400 g. The molars were impacted
3.6 mm and the mandibular plane showed 4.0° of counterclockwise outer rotation. After the gained intrusion, upper and
lower fixed appliances for alignment of the upper and lower
arches were fitted and the intrusion was maintained with wire
ligation between the implants and the molar tubes throughout
the treatment. The intrusion of 3.6 mm was maintained after
the treatment with fixed appliances, whereas the counterclockwise rotation relapsed during later stages of the treatment. This
was caused mainly by the progressive extrusion of the lower
molar teeth. A slight posterior open bite Caused by the acrylic
bite blocks was observed when the intrusion appliance was
first removed. The upper molar were fixed to the zygomatic
implant and not free to extrude and therefore the open bite was
closed by the extrusion of the lower molars (occlusal plane
angle 14.0° to 21.0°).This paper shows within the limitation of
a single case report, that zygomatic anchorage can be successfully used for molar intrusion. Further studies with larger
samples and assessment of long-term stability are required.
Sherwood et al. [2] intruded maxillary molars with
miniplate anchorage described by three case reports. The patients were treated with orthodontic fixed appliances and Tshaped miniplates which were surgically placed between the
first and second molars and fixed with two 5-mm miniscrews
each. Loading began 8 weeks after surgery. Intrusion mechanics were continued for 5.5 months until the AOB were closed.
These case reports lack longer-term follow up.
In skeletal AOB cases, in which the aim is to close an AOB
by intruding the posterior teeth, miniplates and miniscrews are
being used and undesirable side effects of extrusion of anterior
teeth avoided.
276
Several case reports have shown that, at least in the short
term, in the maxilla or the mandible implanted miniplates aid
intrusion of upper and lower molars up to 3–5 mm while also
achieving counterclockwise rotation of the mandible [2, 33,
34]. This treatment enables the orthodontist to close AOB
without extruding the front teeth, which are prone to relapse
and root resorption [16].
Miniplates are more versatile than screws because they can
be placed where anchorage is needed the most. They have the
virtue of three-dimensional stability because they are held in
place by 3 or more screws. Placing them well away from tooth
roots avoids root injury or avoids interference with root movement [2]. Before starting active tooth movement a latency of
one week after insertion is required. The miniplates are usually removed a week before debond [8, 16].
Sugawara et al. examined the amount of relapse after SAS
(sketelal anchorage system) in 9 adult open bite patients who
had been successfully treated. They all had a fixed appliance
combined with SAS to intrude the first and second mandibular
molars bilaterally. Three lateral cephalometric radiographs per
patient have been taken; before the SAS placement (T1), at
debond of fixed appliances (T2) and at 1 year post-debond
(T3) to calculate the amount of intrusion. The average amount
of intrusion was 1.7 mm at the first and 2.8 mm at the second
molar respectively. The average amount of relapse was
0.5 mm at first and 0.9 mm at second molar respectively.
There was no statistically significant difference between the
changes at T1-T2 and T1-T3. Sugawara et al. concluded that
the average relapse rates were 27.2 % at the first molars and
30.3 % at the second molars. Therefore he suggests an
overcorrection of intrusion [16].
Baek et al. examined the long-term stability of AOB correction by intrusion of the maxillary posterior teeth with
miniscrew implants. 9 Patients with diagnosed AOB were
treated with fixed appliances combined with molar intrusion
by miniscrew implants. Lateral cephalometric radiographs
were taken before and after treatment, 1 and 3 years posttreatment. The maxillary first molar was on average intruded
by 2.39 mm and showed a relapse rate of 23 % at the 3-year
follow-up. The authors noticed that 80 % of the relapse
occurred during the first year of retention. An incisor overbite
relapse rate of 17 % with no significant recurrence between
the 1- and 3-year follow-up were noticed. Baek et al. concluded that most relapse occurs during the first year of retention
[35].
Miniplates do however have a number of disadvantages.
There are limited areas for their insertion, they are expensive
and require two surgical procedures for insertion and removal
[36]. Miniscrews on the other hand are used routinely in
orthodontics as skeletal anchorage for tooth movement, are
cheap and easy to use and can often be placed under local
anaesthetic. Some recently published case reports have shown
that teeth can be successfully intruded with miniscrews as
Oral Maxillofac Surg (2014) 18:271–277
skeletal anchorage [15, 19, 36]. Miniscrews inserted into the
maxillary posterior buccal bone can be useful for posterior
intrusion and therefore used for AOB closure. Additionally,
the use of miniscrews for intrusion during active growth
favours counterclockwise rotation of the mandible improving
the vertical and anteroposterior discrepancy [19].
Conclusions
The Orthodontist has a number of treatment modalities available for the management of mild to moderate AOB cases.
With the introduction of TAD as an effective treatment modality, orthognathic surgery may be avoidable in selected
AOB cases. This is a relatively new technique and to date
there remains a lack of evidence of long-term stability of AOB
closure with TAD. Several case reports have illustrated the
successful use of TAD in nongrowing skeletal open bite cases
that may previously have been treated with orthognathic surgery. The treatment of AOB with skeletal anchorage devices
have several advantages compared with single or bimaxillary
jaw surgery providing lower cost, less invasiveness, and less
complicated low morbidity treatment. Further studies in skeletal anchorage devices need to be conducted to ascertain the
long-term stability and effectiveness of this method as a
treatment in the management of AOB cases.
Conflict of interest The authors declare that they have no conflict of
interest.
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