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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 9  |  Issue : 5  |  Page : 7-12

Faciomandibular asymmetry: An analysis of skeletal parameters and possible etiological factors


1 Department of Orthodontics and Dentofacial Orthopedics, JCD Dental College, Sirsa, Haryana, India
2 Department of Orthodontics and Dentofacial Orthopedics, OHSC, PGI CHD, Chandigarh, India

Date of Web Publication15-Sep-2017

Correspondence Address:
Preeti Munjal
JCD Dental College, Sirsa, Haryana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/IJDS.IJDS_36_17

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  Abstract 

Aim and Objectives: The present study has been carried out in an attempt to study the asymmetries of lower one-third of face in terms of etiological factors involved, kind of presentation that it may have, and also to quantify the asymmetry on skeletal aspects. Along with, an attempt has been made to examine if any correlation exists between the severity of asymmetry and presenting age, age of trauma (TrAge), and lag period (LAGPrd). Materials and Methods: The present study was conducted on thirty patients (17 males and 13 females) reporting with a chief complaint of asymmetry at the Dental and Plastic Surgery OPD, PGIMER, Chandigarh, over a period of 2 years. A descriptive pro forma to record signi fi cant medical and dental history was filled to correlate possible etiological factors to the presenting complaint. Along with, posteroanterior cephalogram and orthopantomograms were recorded and traced with speci fi c parameters to correlate them with the present age, TrAge, and LAGPrd. Results: It was concluded that trauma was the single most important possible etiologic factor responsible for facial asymmetry. Assymetry was more apparent in lower third of the face with deviation of chin, fullness of one side and flatness of the other. OPG revealed vertical height of ramus and depth of antegonial notch are affected by trauma and deformity increases with LAGPrd increase. PA cephalogram co-related with similar findings. Conclusion: Faciomandibular asymmetry resulted due to undergrowth or overgrowth of the affected part of mandible. On OPG significant asymmetry was observed which increased with the lag period (difference between age of presenting and age of trauma).

Keywords: Faciomandibular asymmetry, posteroanterior cephalograms, Lag period


How to cite this article:
Munjal P, Utreja A, Mittal S, Sunda S, Arora N. Faciomandibular asymmetry: An analysis of skeletal parameters and possible etiological factors. Indian J Dent Sci 2017;9, Suppl S1:7-12

How to cite this URL:
Munjal P, Utreja A, Mittal S, Sunda S, Arora N. Faciomandibular asymmetry: An analysis of skeletal parameters and possible etiological factors. Indian J Dent Sci [serial online] 2017 [cited 2017 Nov 21];9, Suppl S1:7-12. Available from: http://www.ijds.in/text.asp?2017/9/5/7/214930


  Introduction Top


Symmetry and balance, when applied to facial morphology, refer to the state of facial equilibrium: the correspondence in size, form, and arrangement of facial landmarks on the opposite sides of median sagittal plane.[1],[2]

Human craniofacial investigations as well as cephalometric radiographic studies, in the past, have revealed the presence of asymmetry in the normal facial features.[1],[3],[4],[5]

Asymmetry in facial structures increases with greater distance from the cranium.[6],[7] Thus, maxilla, mandible, and dentoalveolar regions have been shown to exhibit a greater degree of asymmetry than other facial regions. Visual examination is the earliest method used for qualitative analysis, which was later supplemented with radiographic investigations. Posteroanterior (PA) cephalogram has been considered as one of the most valuable diagnostic aids for asymmetry evaluation.[8],[9] It can be supplemented by information gathered from lateral cephalogram, panoramic view, submentovertex view, and among the latest techniques, computed tomography scan.[10],[11]

Mandibular condyle has an important role in craniofacial development, thus being particularly vulnerable to environmental and genetic influences, leading to various disturbances in growth.[11],[12] Multiple causes are attributed to cause growth disturbances in condyle, among which trauma and temporomandibular joint (TMJ) ankylosis have been discussed by many authors in the past.[12],[13],[14],[15],[16],[17],[18],[19],[20] Faciomandibular asymmetry secondary to trauma and joint ankylosis is a common finding. Trauma along with causing undergrowth and ankylosis can also cause overgrowth.[18] The asymmetries in condyle can affect the hemimandible and can alter the orderly progression of development of face.

The present study attempts for a clear understanding of the asymmetry along with the role of condyle in mandibular growth, by accurately describing the etiological factors and presentation of skeletal and dental parameters in faciomandibular asymmetry.


  Materials and Methods Top


Thirty-two patients (18 males and 14 females), with a chief complaint of facial asymmetry reporting at the Department of Oral Health Science Centre and Plastic Surgery OPD, were included in the study and assessed over a period of 2 years. Patients with craniofacial syndromes, active infections, neoplasms, or clefts were excluded from the study.

PA cephalograms were taken on a PM 2002 CC Proline Unit for each patient in standing position and mandible in centric occlusion position with both upper and lower lips relaxed. The exposure factors used for PA cephalogram were 78 kV, 12 mA, and 1.0 s. The corresponding lower values were used for children.

Orthopantomograms (OPGs) were taken with PM 2002cc PROLINE Unit with patients positioned according to recommendations of Philip and Hurst 1978 so as to have minimum distortions. For patients with ankylosis, OPGs were taken in closed mouth position.

X-rays were developed in an automatic processor to have uniform, good-quality cephalograms.

All the cephalograms and OPGs were traced on a single-intensity view box, using 0.5 mm thick lead tracing pencil on 0.003 inches thick matte acetate tracing paper. All the measurements were made by the same examiner to the least count of 0.5 mm for linear and 0.5° for angular measurements [Figure 1].
Figure 1: Posteroanterior cephalogram showing landmarks 1: Roof orbit (Ro) 2: Zygomatic suture point (z) 3: Latero-orbitale (LO) 4: Medio-orbitale (Mo) 5: Pyriform aperture (Nc) 6: Zygion (Zy) 7: Mastoid (Ma) 8: Antegonion (Sg) 9: Maxillare (Mx) 10: Gonion (Go) 11: Inferior Orbitale 12: Crista Galli (Cg) 13: ANS 14. Menton (Me)

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Bilateral landmarks were further dissected to give the midpoint. “Line of best” was drawn through the midline landmarks and midpoint of bilateral landmarks, which was used as mid sagittal plane (MSP) or reference plane. Perpendiculars from bilateral landmarks were projected onto the MSP. Linear horizontal measurements were done and differences were calculated to signify transverse plane discrepancy. Vertical discrepancy was measured on the reference plane to assess discrepancy in vertical plane. Discrepancy in the horizontal and vertical planes among Ag, Go, CD, and Zy was summed up to give horizontal score (H score) and vertical score (V score). Both were added to give the total score (T score) [Figure 2].
Figure 2: Posteroanterior tracing showing vertical distortion measured onto “ the Line of Best Fit” Go-V represents the vertical distortion between the bilateral landmarks “ Gonion (Go)” Ag-V represents the vertical distortion between the bilateral landmark “ Antegonion (Ag)”

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Similarly, OPGs were traced to record various lengths as horizontal ramus height (HRH), ascending ramus length (ARL), length of trunk, ascending ramus, articular process length (APL), articular process base, width of condyle, gonial angle, and depth of antegonial notch [Figure 3] and [Figure 4].
Figure 3: Panoramic radiograph showing landmarks 1: Gonion point (g) 2: Antegonion point (Ag) 3: Height of condyle point (HC) 4: Incisura semilunaris (IS) 5: Alveolar point (AL)

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Figure 4: Panoramic radiograph showing linear and angular measurements 1: Horizontal ramus height 2: Ascending ramus length 3: Length of trunk of ascending ramus 4: Articular process length 5: Articular process base 6: Width of condyle 7: Gonial angle 8: Depth of antegonial notch

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Statistical methods

Assessed parameters included presenting age, age of trauma (TrAge), and the lag period (LAGPrd) which was the difference between TrAge and presenting age. “Degree of correlation” among these variables was assessed. Levels of significance were determined as P< 0.05 and P< 0.01. The total sample was divided into Group 1, patients with undergrowth, and Group 2, patients with overgrowth. This division was re-examined and confirmed by the institute's two experienced orthodontists, according to guidelines of Engel and Brodie [12] and Obwegeser.[11]

Intra-examiner variability and reproducibility

One examiner performed all the registrations, landmark identification, and measurements. To examine possible error in this, approximately 10% of cephalograms and panoramic views were selected randomly. These were retraced and measured after 2 weeks by the same observer, and Student's “t-” test was used to assess intra-examiner reproducibility. Statistically significant difference was not present between the two readings, validating the intra-examiner reproducibility.


  Observations and Results Top


General observation of the patients revealed that asymmetry was more apparent in lower one-third of face with deviation of chin, fullness of one side and flatness on the other side. The history of patients revealed that most of the patients had suffered from trauma to the face in road traffic accident, fall from roof, or over a fight [Table 1] and [Table 2].
Table 1: Possible etiological factors involved

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Table 2: General observations of patients with faciomandibular asymmetry

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A comparison of the total sample was done with three variables: presenting age, trauma age, and LAGPrd. Evaluation of OPG revealed significant degree of negative correlation between trauma age and HRH (r = 0.1854, P< 0.05) and antegonial depth (r = −0.5260, P< 0.05). Significant degree of correlation was also found between LAGPrd and ARL (r = 0.6432, P< 0.001), trunk length (r = 0.5410, P< 0.01), APL (r = 0.4503, P< 0.05), antegonial depth (r = 0.4501, P< 0.05), and total score (r = 0.6731, P< 0.001), thus showing that the vertical height of ramus and depth of antegonial notch are affected by trauma and the deformity increases as the LAGPrd increases [Table 3].
Table 3: Correlation of asymmetry score on orthopantomogram of the total sample (n=30) with present age, age of trauma, and lag period

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The three parameters, i.e., presenting age, TrAge, LAGPrd, were correlated with the horizontal and vertical measures of asymmetry on PA cephalogram. Presenting age of the total sample showed a significant correlation with the difference in antegonial height measured on PA cephalogram [Table 2]. TrAge also showed a significant correlation with difference in gonion height (r = 0.6944, P< 0.0001), difference in maxillare height (r = 0.3898, P< 0.05), difference in condylion height (r = 0.5245, P< 0.01), and total score (r = 0.3974, P< 0.05). Measurements representing distortion in vertical plane between the bilateral landmarks, i.e., difference in antegonial height (r = 0.5805, P< 0.001), difference in condylion height (r = 0.4167, P< 0.05), and vertical score (r = 0.5171, P< 0.05), showed a significant correlation with the LAGPrd [Table 4].
Table 4: Correlation of asymmetry score on posteroanterior cephalogram of the total sample (n=30) with present age, age of trauma, and lag period

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  Discussion Top


Facial asymmetry is a relatively common finding affecting the general population, serving to characterize and individualize an esthetically pleasing face. Asymmetry of a conspicuous nature concerns the patient.[1],[2],[3],[4],[5],[6],[7]

The study center, being a tertiary care center, catered patients from various states of North India, thus being a good representative of North Indian population. Wide age range varying from 3.5 to 29 years points to the fact that onset or concern for the asymmetry can be raised as early as in a 3-year-old child to an adult, depending on the age of onset of deformity, pace of developing deformity, and any functional disability associated with it.

Seventeen patients were male and 13 were female, reflecting that males being more actively involved in outdoor activities are more prone to trauma. Trauma, in the present study, was considered as the main etiological factor. Trauma was due to fall from height, road traffic accident, or over a fight. A similar finding regarding prepubertal trauma causing mandibulofacial asymmetry was supported by Skolnick et al.[17]

Only one case of facial disfigurement due to forceps delivery was reported in the present study and was excluded. Fall from height in children of younger age group was observed as another important etiological factor in the present study. This was supported by Rowe (1969)[13] who also described that children below the age of 5 years were more prone to permanent growth changes following fracture of condylar process. He also said that fracture of condyle produced a growth deficit in proportion to the age at the time of injury; younger the child, greater were the potential growth problems.

Two cases in our study had infection as the etiology, which in literature was supported by Engel and Brodie [12] with respect to middle ear infection and rheumatoid arthritis of the joint as the etiologies.

Among 32 patients, 20 were cases of undergrowth and 12 of overgrowth. Etiological factors responsible for undergrowth have consistently been found to be trauma and infection. Literature also supports trauma to be a possible etiology for overgrowth too(Lineaweaver 1989, Hyekel 1991, and Skolnick (1994),[17] though controversy surrounds the issue. Lund [18] reported compensatory growth in most fractured condyles which can lead to its overgrowth on the affected side in some cases.

General examination revealed asymmetry to be maximum in lower one-third of the face. Scar was present in 19 out of 30 patients, while chin deviation was in 29 patients out of the thirty studied. Speculand (1982)[15]- Proffit (1980)[15] made a similar observation on five cases of condylar hypoplasia and found that restricted development of condyle was accompanied by restricted development of distal end of mandibular body, leading to displacement of chin on the affected side. Head posture was observed to be tilted in 21 patients, the tilt being present toward the side of deformity. This was in an attempt on part of the patient to mask or reduce the underlying deformity.[2]

A discordant midline was observed in 23 of the thirty cases as overgrowth shifts the mandibular midline toward the opposite side, while undergrowth shifts it to the same side. Restricted functional movements were present in 17 out of 20 patients in ankylosis group only. Markey et al. (1980)[16] explained the reduced mouth opening to be due to reduced action of lateral pterygoid, causing suprahyo and infrahyoid muscles to quickly take over the action of lateral pterygoid muscle and cause diminished mouth opening.

PA cephalogram has been considered as the primary source of reaching correct diagnosis in cases of asymmetry (Proffit, 1991).[10] Vig and Hewitt [1] advocated line of best fit as the reference plane. It minimizes the sum of the square of the perpendicular deviation. Results of the present study exhibited that the vertical distortions measured on the PA cephalograms showed a significant correlation with the parameters such as presenting age, TrAge, and LAGPrd. For the undergrowth sample, antegonion and total vertical score were significantly correlated with LAGPrd. Thus, it was inferred that, as the LAGPrd increased, the vertical asymmetry among these landmarks increased. LAGPrd in overgrowth sample was significantly correlated with vertical distortion in antegonion, condylion, and gonion. This was an evidence to the fact that, as the LAGPrd increased, the asymmetry in lower one-third of the face on PA cephalogram increased. The landmarks present in the middle one-third of the face, i.e., zygion and maxillare, showed reduced correlation with the three parameters. This was confirmed by the observation of Peck and Peck (1991)[6] and Vig and Hewitt (1975).[1]

It has been commonly observed in case of lateral cephalogram that, when the left and the right horizontal and ascending ramus are asymmetric and of varying length and width, they are clearly visible as two outlines, especially at the lower border of the mandible. Cook [21] demonstrated that, if condyles were coincident on lateral skull film, lack of superimposition of lower border of the mandible indicated unilateral shortening of ramus or body. This was in agreement with the findings of Hohl et al.,[22] who concluded that untreated TMJ ankylosis in young patients severely affected condyles, body, symphysis, maxilla, temporal bone, and zygomatic process. Chin prominence was significantly reduced, along with reduction in absolute lengths of maxilla and mandible.

Panoramic radiography has become one of the standard tools in orthodontics, though literature also states the lack of satisfactory head positioning device. In the study, only for one vertical measurement, variability exceeded >1%. However, the horizontal variables despite the use of head positioner were found to be unreliable. Obwegeser [11] described this view as the best radiograph for any mandibular anomaly, allowing a clear diagnosis of important points. In the present study, gonial angle difference between the two sides was clearly visualized. The differences in the linear and angular measurements between the two sides were carried out, which negated the effect of the distortion or magnification of the structures produced. Individual scores were added to give the total OPG score, which represented the total asymmetry measured on OPG. LAGPrd showed a strong association with ARL and trunk length, HRH, and apical process length. The difference in the depth of antegonial notch between the two sides and the OPG score showed a distinct correlation with the LAGPrd. In case of undergrowth patients, this is an evidence to the direct proportionality between asymmetry score on OPG and LAGPrd.


  Summary and Conclusions Top


This investigation was undertaken with the aim to assess skeletal parameters and possible etiologic factors associated with faciomandibular asymmetry. The present study was conducted on thirty patients (17 males and 13 females) who reported with a chief complaint of facial asymmetry at dental OPD and Plastic Surgery OPD, PGIMER, Chandigarh, over a period of 2 years. None of the patients involved had any syndromic involvement or any gross physical and mental disability. The total number of patients reporting were 32, but 2 were excluded due to unidentified etiology. A descriptive pro forma to record medical and dental history was filled, which revealed that 28 patients suffered from trauma and two from infection.

PA cephalogram and OPGs were traced and evaluated. The asymmetry scores obtained from them were correlated with the presenting age, TrAge, and the LAGPrd obtained.

The following conclusions were drawn:

  • Trauma was found to be the most important possible etiologic factor
  • Faciomandibular asymmetry resulted in either undergrowth or overgrowth of the affected part of mandible, former being twice more common
  • In undergrowth cases, as the LAGPrd increased, the severity of deformity also increased. Younger the child at the onset of trauma, more severe is the deformity.


Although the results of the present study are in accordance with the observations made on patients with faciomandibular asymmetry and those present in the literature, definite preclusions should be precluded due to smaller sample size studied.

.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Vig PS, Hewitt AB. Asymmetry of the human facial skeleton. Angle Orthod 1975;45:125-9.  Back to cited text no. 1
    
2.
Shah SM, Joshi MR. An assessment of asymmetry in the normal craniofacial complex. Angle Orthod 1978;48:141-8.  Back to cited text no. 2
    
3.
Bishara SE, Burkey PS, Kharouf JG. Dental and facial asymmetries: A review. Angle Orthod 1994;64:89-98.  Back to cited text no. 3
    
4.
Sutton PR. Lateral facial asymmetry-methods of assessment. Angle Orthod 1968;38:82-92.  Back to cited text no. 4
    
5.
Letzer GM, Kronman JH. A PA cephalometric evaluation of craniofacial asymmetry. Angle Orthod 1979;49:199-204.  Back to cited text no. 5
    
6.
Peck S, Peck L, Kataja M. Skeletal asymmetry in esthetically pleasing faces. Angle Orthod 1991;61:43-8.  Back to cited text no. 6
    
7.
Smith RJ, Bailit HL. Prevalence and etiology of asymmetries in occlusion. Angle Orthod 1979;49:199-204.  Back to cited text no. 7
    
8.
Mulick JF. Clinical use of the frontal headfilm. Angle Orthod 1965;35:299-304.  Back to cited text no. 8
    
9.
Athanasiou AE, editor. Orthodontic Cephalometry. 2nd ed. Philadelphia: W.B. Saunders Company; 1994  Back to cited text no. 9
    
10.
Proffit WR, White RP. Surgical Orthodontic Treatment. St. Louis: The CV Mosky Co.; 1991.  Back to cited text no. 10
    
11.
Obwegeser HL: 2001. Mandibular growth anomalies. Springerverlag Berlin Heidelberg GmbH.  Back to cited text no. 11
    
12.
Engel MB, Brodie AG. Condylar growth and mandibular deformities. Surgery 1947;27:497-507.  Back to cited text no. 12
    
13.
Rowe NL. Fractures of the jaws in children. J Oral Surg 1969;27:497-507.  Back to cited text no. 13
    
14.
Waite DE. Pediatric fractures of jaw and facial bones. Pediatrics 1973;51:551-9.  Back to cited text no. 14
    
15.
Proffit WR, Vig KW, Turvey TA. Early fracture of the mandibular condyles: Frequently an unsuspected cause of growth disturbances. Am J Orthod 1980;78:1-24.  Back to cited text no. 15
    
16.
Markey RJ, Potter BE, Moffett BC. Condylar trauma and facial asymmetry: An experimental study. J Maxillofac Surg 1980;8:38-51.  Back to cited text no. 16
    
17.
Skolnick J, Iranpour B, Westesson PL, Adair S. Prepubertal trauma and mandibular asymmetry in orthognathic surgery and orthodontic patients. Am J Orthod Dentofacial Orthop 1994;105:73-7.  Back to cited text no. 17
    
18.
Lund K. Mandibular growth and remodelling processes after condylar fracture. A longitudinal roentgencephalometric study. Acta Odontol Scand Suppl 1974;32:3-117.  Back to cited text no. 18
    
19.
Leake D, Doykos J 3rd, Habal MB, Murray JE. Long-term follow-up of fractures of the mandibular condyle in children. Plast Reconstr Surg 1971;47:127-31.  Back to cited text no. 19
    
20.
Berraquero R, Palacios J, Gamallo C, de la Rosa P, Rodriguez JI. Prenatal growth of the human mandibular condylar cartilage. Am J Orthod Dentofacial Orthop 1995;108:194-200.  Back to cited text no. 20
    
21.
Cook JT. Asymmetry of the cranio-facial skeleton. Br J Orthod 1980;7:33-8.  Back to cited text no. 21
    
22.
Hohl TH, Shapiro PA, Moffett BC, Ross A. Experimentally induced ankylosis and facial asymmetry in the macaque monkey. J Maxillofac Surg 1981;9:199-210.  Back to cited text no. 22
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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