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Academia Journal of Medicinal Plants 2(1): 001-005, January 2014
DOI: http://dx.doi.org/10.15413/ajmp.2013.0116
ISSN: 2315-7720
©2014 Academia Publishing
Research Paper
Evaluation of the Novel Midsagittal line for diagnosis of craniofacial asymmetry
Accepted 7th October, 2013
ABSTRACT
M. Ordobazari1*, A. H. Zafarmand1, A.
Naghavi
Alhosseini2
and
A.
Ordobazari3
1Department
of Orthodontics, Shahid
Beheshti University, School of
Dentistry Tehran, Iran.
2Orthodontist, Private Practice.
3Department
of Pathology, MCW
(Medical College of Wisconsin),
Milwaukee WI, USA.
*Corresponding author.
E-mail: [email protected].
Tel: 0098 – 21 – 88771909.
The purpose of this study was the determination of midsagittal reference line
(MSL) for craniofacial asymmetry assessment by drawing a line from Crista gali
parallel to the true vertical line in PA cephalometry using Natural Head Position
(NHP) technique. 60 samples (30 males and 30 females, within the age range of 9
to 13 years old Iranian population) were selected with normal class I occlusion
without any history of orthodontic or jaw surgery treatments. Patients had no
supernumerary or missing teeth and any skeletal anomaly. Postero Antero
cephalometry radiographs (PA Cephalograph) were taken from all samples with
NHP technique. The midsagittal line was also traced parallel to the hanging chain
from the intracranial reference point (Crista gali). This line is a true vertical line.
True horizontal lines were traced perpendicular to the hanging chain from Crista
gali (Cg). We can assess craniofacial symmetry with linear, angular and
trigonometrical measurements in PA cephalometric radiographs by NHP
technique, using true vertical and horizontal lines. The mean differences of the
aforementioned measurements in left and right sides were analyzed by T- test.
Each variable was measured independently; then, the mean values and standard
deviation calculated separately. Also, transverse ratios were prepared in our
samples (age range of 9 to 13 years). All patients were from Iranian decent. For
midsagittal line (MSL) validity, the ANS (Anterior Nasal Spine) distance in the
middle third and Me (Menton) distance in lower third from Midsagittal line (MSL)
was measured. Findings of this study showed that PA cephalometry with NHP
technique could assess the facial symmetry with the rate 96% confidence interval.
Therefore, the introduced midsagittal line using NHP technique could prove the
ability for diagnosis of facial asymmetries.
Key words: Natural head position (NHP), midsagittal line, facial asymmetry, true
vertical line, true horizontal line, crista gali, maxillofacial surgery, orthodontics,
radiology.
INTRODUCTION
Different methods with versatile features are proposed for
diagnosis of facial asymmetries. By using these methods,
clinicians can identify location and the amount of skeletal
deformities causative of asymmetries (Fong et al., 2010;
Grummons and Dappsyne, 1987; Betts et al., 1995; Aoshia,
1990; Grayson and Mccarthy, 1983-1984).
Conventional methods for assessment of asymmetry are
based on intracranial tow landmarks. Researchers such as
Betts et al. (1995), Grayson and Mccarthy (1983-1984) and
Mongini et al. (1991) used two intracranial landmarks
introducing conventional midsagittal line as a reference for
diagnosing facial symmetry. However, credibility of this
reference line depends on the landmarks which can be
affected by asymmetries (Fong et al., 2010; Madsen et al.,
2008). As such, validity of this reference line is
questionable.
Due to controversies and statistical differences in
previous studies, it became necessary proposing a new
Academia Journal of Medicinal Plants; Ordobazari et al.
002
Figure 1. The film, chain and patient’s position for taking PA cephalogram with NHP technique (A: posterior view and B: lateral view)
technique with a more valid reference line for PA
cephalometric analysis. The aim of this study was
evaluation of midsagittal reference line for assessment of
maxillofacial asymmetry in maxillofacial surgery,
orthodontics and maxillofacial radiology fields. This is
accomplished by using an intracranial landmark of Crista
Gali with the true vertical line (a hanging chain near the
patient’s face), while patient look into mirror to his/her
own eyes (Chen et al., 2008).
The benefit of using this new reference line (MSL) is its
independency from inconsistent intracranial structures
(Cuccia and Carola, 2009).
MATERIALS AND METHODS
60 orthodontic samples (30 males and 30 females) were
selected with normal occlusion. Patients were 9 to 13 years
old and had no skeletal discrepancy, supernumerary,
missing tooth, any past history of orthodontic treatment or
jaw surgery. PA cephalometry radiographs were taken with
NHP technique (in standing position), while patients looked
at front mirror to his/her eyes (Mirror designed on the
cassette by a special stick and against the wall in front of
the patient) and hanging a chain near the face from all
samples (Figure 1a and b), then, midsagittal line was traced
parallel to the hanging chain from Crista Gali (Figure 2).
This midsagittal line is the true vertical line, the line
drawn from Crista Gali parallel to hanging chain. The true
horizontal line was traced perpendicular to the midsagittal
line (true vertical line). Accordingly, the craniofacial
symmetry was assessed on the basis of linear and angular
measurements as well as, triangular ratios. Finally, this
technique was tested so as to determine the standard
transverse dimension for Iranian children.
PA cephalometry with NHP technique has specific value
for assessing symmetry of a face (Figure 2); the mean
differences of the aforementioned measurements in left and
right sides were analyzed by T- test. Three determinant
points were initially considered for evaluating facial
symmetry in this study namely: A) reference points in the
upper third of face; B) reference points in the middle third
of face and C) reference points in lower third of face. PA
cephalogram tracings was done by one person using
Canson 224 × 210 dimension tracing paper with a black
pencil (diameter 0.5 mm).
RESULTS AND DISCUSION
As was mentioned earlier, linear variables, transverse,
angular and triangular ratios were used for symmetric
assessment. According to these linear variables, we
assessed transverse ratios based upon the defined left and
right of craniofacial landmarks (Tables 1 and 2).
Furthermore, according to the distance ratio from the
midsagittal line in left and right sides of PA cephalometry
radiograph, we assessed symmetry of face by true vertical
Academia Journal of Medicinal Plants; Ordobazari et al.
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Figure 2. Postero-anterior cephalogram in NHP technique.
Table 1. Mean and S.D. of dentofacial linear variables in 9 to 13 years Iranian children.
Linear variable
Lo-Lo
Pt-Pt
Es-Es
J-J
Zg-Zg
Ma-Ma
Um-Um
Ag-Ag
Lm-Lm
Co-Co
Mean
92.2
51.3
93.8
63.6
123.5
108.8
59.6
82
59.6
98
Standard deviation
3.2
6.2
4
3.4
5.2
5.8
3.7
3.8
4
2.5
Lo = Latero-Orbital; Pt = Petrous; Es = Sphenoid; J = Jugale; Zg = Zygoma; Ma = Mastoid, Um =
Maxillary molar; Ag = Antegonion; Lm = Mandibular and Co = Condylion.
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004
Table 2. Mean and Standard deviation of dentofacial transverse ratio in 9 to 13 years Iranian children.
Transverse ratio variables
J-J / Lo-Lo
Ag-Ag / Lo-Lo
J-J / Ag-Ag
Um-Um / J-J
Lm-Lm / Ag-Ag
Um-Um / Lm-Lm
Zg-Zg / Cg-Me
Cg-ANS / Cg-Me
ANS-Me / Cg-Me
Mean
0.69
0.89
0.78
0.92
0.72
1.01
1.20
0.47
0.53
Standard deviation
0.04
0.04
0.04
0.03
0.06
0.04
0.07
0.03
0.03
Cg = Crista gali, Me = Menton and ANS = Anterior nasal spine.
and horizontal line. Each variable was measured
independently and transverse ratios were prepared in all
samples and then, their mean and standard deviation was
calculated.
For midsagittal line (MSL) validity assessment, in middle
third, the ANS distance and in lower third, the Me (Meton)
distance from symmetry line was measured. The mean and
standard deviation of these distances from MSL was
calculated for all images. Obviously, if ANS and Me adapted
on MSL, their distances were considered as zero; the
differences of mean values were analyzed by T-test.
All previous studies (Fong et al., 2010; Grayson and
Mccarthy, 1983-1984; Athanasiou et al., 1992) for
asymmetry assessment were based upon conventional PA
cephalometry method, but in this study, PA cephalometry
used NHP method. As such, many shortcomings of previous
studies were carefully observed.
With this method, an extra-cranial landmark was used
and each variable was measured, independently. In
addition, this landmark has the advantage of high
reproducibility. As opposed, the other intracranial anatomic
landmarks are highly variable in different samples (Madsen
et al., 2008). Transverse ratios in our samples were
prepared. Also, personal errors and difficulties in symmetry
assessment due to head movements and rotations were
eliminated during the process of preparing PA cephalogram
(Araujo and Wilhelm, 1994).
As discussed, reference line for dentofacial landmarks
assessment is traced according to extra-cranial landmark
(true horizontal and vertical lines) and by the fixed point
(Crista Gali). Thus, difficulties and errors in conventional
methods due to determining different intracranial
landmarks by different operators were reduced
significantly (Chen et al., 2008; Cuccia and Caradonna,
2009).
Reported methods by other researchers can assess only
dental and skeletal landmarks according to median axis of
face, except computer based method of Mongini which
needs a sophisticated software component (Mongini et al.,
1991). Transverse ratio analysis used in this study
eliminated errors due to magnification. Since the age range
of samples was limited to 9 to 13 years old Iranian children,
the results of transverse ratio can be observed as a valuable
reference for transverse dentofacial measurements. This
range was different compared to the study of Athanasiou et
al. (1992).
In the NHP method, in addition to reproducibility of X-ray
procedures using extra-cranial landmarks, symmetry
assessment is true and predictable up to 96%, which was
similar to the report of Madsen et al. (2008).
Conclusions
In postero-anterior cephalometry radiographs analysis
with NHP method, Crista Gali, an extra-cranial landmark, is
reliable for assessment of facial symmetry with minimum
errors and maximum validity in the skull region, highly
reproducible and up to 96% times symmetries or
asymmetries were detectible.
Findings of this study showed that PA cephalometry with
NHP technique could assess the facial symmetry at the rate
of 96% confidence interval. Therefore, the introduced
midsagittal line using NHP technique could prove the
ability for diagnosis of facial asymmetries.
REFERENCES
Fong JH , Wu HT , Huang MC , Chou YW , Chi LY , Fong Y , Kao SY (2010).
Analysis of facial Skeletal characteristics in patients with chin deviation.
J. Chin. Med. Assoc. 73(1):29-34.
Grummons DC, Dappsyne MAG (1987). A frontal asymmetry analysis. J.
Clin. Orthod. 21:448-463.
Betts N, Vanarsdall L, Dexter H, Barber K, Fonseca J (1995). Diagnosis and
treatment of transverse maxillary deficiency. Int. J. Adult Orthog. Surg.
10:75-96.
Aoshia O (1990). Investigation of the facial symmetry of cases with cross
bites needing surgical orthodontic treatment using posteroanterior
roentgenographic cephalometric. Nippon Kyosei. pp.256-62.
Grayson BH, Mccarthy G (1983-84). Analyses of craniofacial asymmetry by
Multiplan cephalometry. Am. J. Orthod. 217-224.
Academia Journal of Medicinal Plants; Ordobazari et al.
Mongini F, Schmid W, Felliso A (1991). A computer based assessment of
structural and displacement asymmetry of the mandibule. Am. J. Orthod.
100(1):19-34.
Madsen DP, Sampson WJ, Townsend GC (2008). Craniofacial reference
plane variation and natural head position. Eur. J. Orthod. 30:532-40.
Chen CM, Lai S, Tseng YC, Lee KT (2008). Simple technique to achieve a
natural head position for cephalography. Br. J. Oral. Maxillofac Surg.
46(8):677-8.
Cuccia AM, Carola C (2009). The measurement of craniocervical posture: a
simple method to evaluate head position. Int. J. Pediatr.
Otorhinolaryngol. 73(12):1732-6.
Athanasiou E, Drosche H l, Bosch C (1992). Data and patterns of transverse
den to facial structure of 6 to 15 years old children: A posteroanterior
cephalometric study. Am. J. Orthod. 101(4):65-71.
Araujo P, Wilhelm SA (1994). Skeletal and dental arch asymmetrics in
individuals with normal dental occlusion. Int. J. Adult Orthog. Surgery.
9:111-118.
Cuccia AM, Caradonna C (2009). The natural head position. Different
techniques of head positioning in the study of craniocervical posture.
Minerva Stomatol. 58(11-12):601-12.
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Cite this article as:
Ordobazari M, Zafarmand AH, Alhosseini AN, Ordobazari A
(2014). Evaluation of the Novel Midsagittal line for diagnosis
of craniofacial asymmetry. 2(1): 001-005.
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