Download Nasolabial and Interincisal Angle Evaluation in Anterior Maxillary

10.5005/jp-journals-10021-1286
Tojan Chacko Thekkekara et al
Original Article
Nasolabial and Interincisal Angle Evaluation in Anterior
Maxillary Distraction Osteogenesis: A Case Study
1
Tojan Chacko Thekkekara, 2Varghese Mani, 3Kuriakose Antony, 4Binnoy Kurian
ABSTRACT
Maxillary hypoplasia is a common developmental problem
in cleft lip and palate deformities. These deformities have
traditionally been corrected by means of orthognathic surgery.
Management of skeletal deformities in the maxillofacial
region has been a challenge for maxillofacial surgeons and
orthodontists. Distrac­tion osteogenesis (DO) is a surgical
technique that uses body’s own repairing mechanisms for
optimal reconstruction of the hard and soft tissues. We present
four cases of anterior maxillary distraction osteogenesis with
tooth-borne distraction device—Hyrax, which were analyzed
retrospectively using cephalometrics. Changes in nasolabial
angle and interincisal angle after distraction of anterior maxillary
segment were studied to conclude that there was no much
change in the the nasolabial angle while the interincisal angle
showed marked improvement.
Keywords: Anterior maxillary distraction, Hyrax, Cleft lip and
palate.
How to cite this article: Thekkekara TC, Mani V, Antony K,
Kurian B. Nasolabial and Interincisal Angle Evaluation in Anterior
Maxillary Distraction Osteogenesis: A Case Study. J Ind Orthod
Soc 2014;48(4):406-411.
Source of support: Nil
Conflict of interest: None
Received on: 22/10/13
Accepted after revision: 29/11/13
INTRODUCTION
Distraction osteogenesis is a method of endogenous tissue
generation in which new bone is mechanically induced
within the space between opposing bone surfaces that are
1
4
Professor, 2Dean, 3Postgraduate Student,
Consultant Orthodontist
1
Department of Orthodontics, Mar Baselios Dental College
Kothamangalam, Kerala, India
2
Department of Oral Surgery, Mar Baselios Dental College
Kothamangalam, Kerala, India
3
Department of Orthodontics and Dentofacial Orthopedics, Mar
Baselios Dental College, Kothamangalam, Kerala, India
4
Department of Orthodontics and Dentofacial Orthopedics
Zentizt Dental Clinic, Kochi, Kerala, India
Corresponding Author: Tojan Chacko Thekkekara, Professor
Department of Orthodontics, Mar Baselios Dental College
Kothamangalam, Kerala, India, Phone: 04852823740, e-mail:
[email protected]
406
gradually separated by means of incremental traction. Bone
elongation technique was pioneered by Codvilla, who in
1905 published a case report of femoral extension using
axial forces of distraction.1
The development of distraction osteogenesis has received
an outstanding contribution from the work of Ilizarov, a
Russian scientist, who in 1953 explained the scientific basis
for the bone formation between the vascularized margins of
osteotomized long bones. Ilizarov showed that lengthening
of the long bones is possible without using a graft material.2-5
Use of this concept of distraction osteogenesis in the
craniofacial skeleton experimentally was first reported by
Snyder in 1973.6 Distraction osteogenesis (DO) is rapidly
becoming an alternative technique to treat craniofacial
dysplasias .It was initially used successfully to treat unilateral
or bilateral mandibular dysplasias.7
In 2003, the first successful clinical application of
anterior maxillary segmental distraction (AMSD) using
an intraoral toothborne distraction device was reported by
Dolanmaz8 in a noncleft patient. He reported an advancement
of 8 mm using an intraoral toothborne distraction device.
Wang XX et al9 in a clinical study treating the patients
by anterior maxillary segmental distraction using internal
distraction device and external distraction device reported to
have achieved around 10.5 mm of advancement of maxilla
and no patient had any sign of velopharyngeal morphological
changes or speech deterioration. According to the study, the
possible reasons for that are muscles of the velopharynx
are not affected by anterior maxillary advancement and
velopharyngeal mechanism is unaltered.
Block et al10-12 used tooth-borne and implant supported
devices and demonstrated anterior maxillary advancement
in dogs. They concluded that when a tooth-borne device
was used, dental movements exceeded bone movements
and relapse tendency is more.
The concept of gradually advancing the maxilla after
Le fort1 osteotomy was originally presented by Molina and
Monasterio.13 In this technique, an orthodontic face mask
with elastics was used to deliver the traction force to maxilla.
Figueroa AA et al 14 in 1999 analyzed 14 patients
treated by maxillary distraction osteogenesis after complete
osteotomy with a rigid external maxillary distraction device
and found that to be highly effective treatment modality to
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Nasolabial and Interincisal Angle Evaluation in Anterior Maxillary Distraction Osteogenesis: A Case Study
manage cleft-related maxillary hypoplasia. The technique
allows vector control of the osteotomized maxilla throughout
the distraction process.
Altuna et al15,16 used a tooth-borne device and reported
reliable maxillary advancement in primates. Distraction
osteo­g enesis can achieve advancement exceeding the
advance­ments of the conventional osteotomies by 2 to
3 folds. This is because distraction osteogenesis by gradual
stret­ching can overcome the natural soft tissue resistance, and
can accommodate generating new soft tissue (histogenesis)
simultaneously with skeletal augmentation.
According to Keudstall MJ and Vanderwal et al 17,
Rotterdam palatal distractor-bone borne distractor used for
the expansion of the transverse hypoplastic patients, like
cleft palate gives more of an orthopedic expansion of the
maxilla rather than tooth tipping.
Materials and methods
All the four patients included were above the age of
18 years with unilateral cleft lip and palate. Every patient
was bonded with 0.022" slot MBT bracket system. In two
cases, alveolar bone grafting had not been done. Initial
alignment was done with 0.012", 0.014" and 0.016" nickel
titanium wires. After initial alignment, 0.019" × 0.025"
nickel titanium wires were placed to get mild transverse
expansion. Space was created in the premolar region using
open coil springs on both sides to perform osteotomy. After
attaining the adequate space, upper 1st molars and 2nd
premolars were banded and impressions were made with
the bands in place. Casts were prepared and hyrax screw
(13 mm expansion) was soldered to the bands. Appliance
was preoperatively checked in patient’s mouth and kept
in place without activation for a period of 1 month so
that the patient gets acquainted with the appliance. The
Fig. 1: Hyrax appliance preoperative
same appliance was used later for distraction for anterior
maxillary osteotomy; the appliance was placed with an orien­
tation of 90o keeping the appliance parallel to mid-palatine
plane, such that its acti­vation results in anteroposterior
movement and no trans­verse movement (Fig. 1).
The preoperative, postoperative after distraction and
1 year postoperative lateral cephalogram were analyzed for
changes in nasiolabial angle and interincisal angle.
Surgical Technique
Maxillary vestibular incision was made from 1st molar to
contra­lateral first molar under general anesthesia with naso­
endotracheal intubation. The infraorbital foramen and pyri­
form apertures were exposed by raising the Muco­periosteal
flap. Horizontal cuts were made 6 mm above the apices of the
canine and parallel to occlusal plane, till the pre­determined
site of distraction. Lateral osteotomy of the lateral wall of the
pyriform rim was done at the same level of the buccal cut,
with care not to damage the nasal mucosa. The vertical cuts
in the buccal cortex were made between the premolars and
molars. The palatal mucosa was undermined, osteotomy
was done using bur and osteotome. The anterior segment
was mobilized using gentle digital pressure. The activator is
activated intraoperatively to check the mobility of maxillary
segment. The vestibular incision is closed using 3-0 vicryl
suture material in layers.
In two cases, bilateral sagittal split osteotomy was done
along with the distraction of the anterior maxilla, to correct
the mandibular excess.
Activation
After a 3 days’ latency period, the activation was started.
Distraction was done at the rate of 0.5 mm (2 turns) twice
a day for a period till the predetermined advancement was
Fig. 2: Hyrax appliance postdistraction
The Journal of Indian Orthodontic Society, October-December 2014;48(4):406-411
407
Tojan Chacko Thekkekara et al
achieved by the same person (Fig. 2). Once the activation
was completed, the appliance was left in situ for the
consolidation period of 3 months. Lateral cephalogram
(Figs 3A to C) were taken immediately after completion of
distraction, and after 1 year interval for evaluation of the
nasolabial angle and interincisal angle.
Postsurgical Orthodontic Phase
Postsurgically, the anterior open bite was corrected with
anterior box elastics which also gave a mild retraction of
upper incisors. After closing of anterior open bite arch
wire was changed to 0.019" × 0.025" SS wire. Distraction
space was maintained using open coil springs. Later, fixed
prosthesis was placed in the distracted area.
Results
The nasolabial (Table 1) showed a mean reduction of 12.5o
immediately after distraction but returned to almost the
same value after 1 year of surgery with only 0.5o mean value
increase. The interincisal angle (Table 2) showed a mean
value reduction of 29.75o immediately after distraction and
returned to normal values with improvement of 19.5o after
postsurgical orthodontics.
The speech of the patients was formally assessed with
speech therapist but no worsening in the speech was reported
during and post-treatment period. The postoperative,
A
distraction and consolidation periods were uneventful in
our cases (Figs 4A to D).
DISCUSSION
Craniofacial distraction osteogenesis has become an
accepted method worldwide for the treatment of congenital
and acquired craniofacial anomalies. Le Fort I osteotomy
with direct advancement has many disadvantages when used
for the correction of hypoplastic maxilla in cleft lip and
palate patients, such as limited advancement, requirement
of bone graft, negative effect on velopharyngeal mechanism,
high risk bone necrosis and relapse.18,19 In cleft lip and palate
patients, where more amount of maxillary advancement
is needed, mandibular setback along with maxillary
advancement is done to correct the skeletal relation. The
disadvantage of this two jaw surgery is that setback of a
normal mandible can compromise final lower facial form,
esthetics and facial harmony (Table 3).
Anterior maxillary osteotomy is mainly indicated
for the correction of maxillary dentoalveolar protrusion.
Three techniques are currently used to achieve the anterior
maxillary osteotomy, Wassmund osteotomy, Wunderer
osteotomy and maxillary anterior down fracture osteotomy
by Epker.
Osteotomy cuts are essentially the same but each
technique varies only in the incision design, access to the
B
C
Figs 3A to C: (A) Preoperative lateral cephalogram, (B) Postdistraction lateral cephalogram, (C) One year postdistraction
Table 1: Nasolabial angle
Table 2: Interincisal angle
Sl.
no.
Predistraction Distraction A-B
A
B
END of
treatment C
A-C
Sl.
no.
Predistraction Distraction A-B
A
B
End of
treatment C
A-C
1
82
67
15
82
0
1
128
110
18
2
57
48
9
56
–1
2
140
108
32
121
22
3
90
77
13
92
2
3
140
107
33
121
23
4
95
83
12
96
1
4
143
122
21
128
15
0.5
Mean
Mean
408
12.25
95
33
29.75
19.5
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Nasolabial and Interincisal Angle Evaluation in Anterior Maxillary Distraction Osteogenesis: A Case Study
Figs 4A : Preoperative lateral profile
Fig. 4B: One year postoperative lateral profile
Fig. 4C: Preoperative occlusion
Fig. 4D: One-year postoperative occlusion
Table 3: ANS-PNS value and relapse
devices of Zurich ramus distractor for anterior maxillary
advancement. The patient achieved satisfactory final
occlusion and considerable esthetic improvement.
Maxillary distraction following anterior maxillary osteo­
tomy has many advantages including greater advancement
of the anterior maxilla, more stable and reliable long-term
results, no need for bone graft, reduced negative effect on
the velopharyngeal mechanism. Because of these reasons,
distraction osteogenesis is used for the maxillary advance­
ment in the cleft lip and palate cases.23
Clinical parameters that affect the treatment outcome of
distraction osteogenesis include the following:2
• Age of the patient
• Surgical technique
• Distraction device
• Rate of distraction
• Rhythm of distraction
• Latency period
• Consolidation period
Sl. Predistraction Distraction
no. (ANS-PNS)
(ANS-PNS)
End of treatment
(ANS-PNS)
Relapse
1
51
0
44
51
2
44
53
53
0
3
45
52
52
0
4
44
54
52
2
maxillary bone and direction of maxillary mobilization.
Advance­ment of the anterior maxilla by osteotomy is tech­
nically difficult because of tight palatal muco­periosteum.
Bengi20 et al used an individual tooth-borne distraction
device to advance the maxillary segment in seven patients. The
results showed that the premaxilla moved anterosuperiorly.
The soft tissue profile showed improvement, the length of
the palatal plane and maxillary arch increased and sufficient
space was gained to align the crowded teeth. Karakasis21
et al in 2004 presented a case report of gradual distraction
osteogenesis using two intraoral bone borne unidirectional
The Journal of Indian Orthodontic Society, October-December 2014;48(4):406-411
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Tojan Chacko Thekkekara et al
Usually for distraction, two types of distractors can
be used, external or internal distractors. Selection of a
distraction device is based upon the surgical goals intended
for the individual patient. The basic goals of any maxillary
advance­ment surgery are to create a stable functional
occlusion and good facial esthetics.
Concerning the choice of distractors, there is a strong
trend toward internal distractors. The advantage of the internal distractors includes the unaltered social life of the patient.
The eventual need for a second surgery to remove the device
is the disadvantage of the internal bone borne distractors.
External bone borne distractors can produce facial scars,
increased potential for sensory damage, infections, altered
social life of the patient and need for special care throughout
the treatment. So, in the reported cases, tooth-borne internal
distractor, Hyrax was employed.
Block et al12 used tooth-borne and implant-supported
devices to demonstrate anterior maxillary advancement in
dogs. According to them, when a tooth-borne device is used,
dental movement exceeds skeletal movement and the relapse
tendency is more in the long term.
The optimum callus distraction is 1 mm daily. Fast
distraction leads to ischemia and delayed ossification or
pseudoarthrosis. Slow distraction results in premature
ossification and consolidation. Illizarov showed that
osteogenic activity was more when DO was performed
0.25 mm for four times a day. In our patients, we performed
0.5 mm of distraction twice daily. The advantage of this is
that frequency of daily visits to hospitals could be reduced.
According to Illizarov, success of DO depends on
res­ponse of initial callus to tensile strength. In the endo­
chondrial bone, a latency period of 5 to 7 days after surgery
is necessary to allow time for callus formation and healing of
soft tissues. The membranous bones of craniofacial skeleton
which were thin and with rich blood supply require much
shorter latency period. We preferred a latency period of
3 days in our patients.
After distraction was completed, open bite resulted.
Gateno et al22 have reported that if the distraction force
is applied below the center of resistance of the maxilla, a
counterclockwise rotation will be induced with a tendency
toward an anterior open bite. The opposite is true for forces
above center of resistance which can end up in clockwise
rotation of the maxilla. So when an intraoral toothborne device
is used, it ends up in anterior open bite. This is a disadvantage
noticed while using the toothborne distractor. The above
situation is because the distraction force is applied coronal to
the center of resistance of the osteotomized maxilla.
In the reported cases, the nasolabial angle became more
acute after distraction. This was due to the anticlockwise
410
rotation of the maxilla resulting in anterior open bite. Later
after using intraoral box elastics, the anterior open bite was
corrected and the nasolabial angle returned to the initial
values.
The interincisal angle was more initially because of
anterior crossbite. Following distraction, the interincisal
angle became acute due to the anterior open bite and
proclination of upper anteriors. Later after using box elastics,
the incisors retruded and the interincisal angle returned to
the normal range.
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