IP Indian Journal of Orthodontics and Dentofacial Research

Print ISSN: 2581-9356

Online ISSN: 2581-9364

CODEN : IIJOCV

IP Indian Journal of Orthodontics and Dentofacial Research (IJODR) open access, peer-reviewed quarterly journal publishing since 2015 and is published under the Khyati Education and Research Foundation (KERF), is registered as a non-profit society (under the society registration act, 1860), Government of India with the vision of various accredited vocational courses in healthcare, education, paramedical, yoga, publication, teaching and research activity, with the aim of faster more...


  • Article highlights
  • Article tables
  • Article images

Article statistics

Viewed: 145

PDF Downloaded: 99


Hemanth M, Aamani, Sharmada B K, Kabbur, and Kalladka: A novel method using 3D CBCT to assess anterior malar prominence among native Bangalore population- A descriptive study


Introduction

Orthodontists are concerned with establishing balance in facial profile and occlusion1 of which midface is considered to be of prime importance. Shape of the lateral segment of the middle third of the face is defined by malar prominence.2 Malar prominence differs among various ethnic groups3 and also gender dimorphism exists.4 Many traditional techniques for evaluation of malar symmetry, by palpation, photometry, or cephalometry was done. A major drawback of these techniques is that 2D lines are used to locate a 3D structure.5 In this study, we describe a novel method to locate the malar eminence using 3D-CBCT which will be helpful in orthodontic diagnosis and treatment planning for malar augmentation, camouflage treatment in subjects with midface deficiencies.

Materials and Methods

Study sample includes 42 subjects (Group A-21 males and Group B- 21 females), aged 18 -36 years belonging to Bangalore population. CBCT scans of these subjects were retrieved from the existing data available in Radiology Imaging Solutions, Bangalore.

Inclusion criteria

  1. Native Bangalore population

  2. Balanced facial appearance

  3. Mesoprosopic facial profile

  4. Mesocephalic subjects

  5. Mesomorphic body type

  6. Average growth patterns

  7. Skeletal class I pattern subjects (esthetically pleasing facial profile)

  8. No previous orthodontic or orthognathic treatment

  9. No history of trauma to craniofacial skeleton

  10. No asymmetry

Exclusion criteria

  1. Growing patients

  2. Vertical and horizontal growth patterns

  3. History of orthodontic treatment

  4. History of maxillofacial or plastic surgery

  5. Subjects with craniofacial syndromes

  6. Subjects with craniofacial trauma

  7. Jaw discrepencies.

All scans were obtained from CBCT (J MORITA 3D Accuitomo, Kyoto, Japan) 170, 4th generation, Voxel size 80 um, Field of view (FOV): 170 X 120mm according to the inclusion criteria. The scans were converted into DICOM format data, which will be then reconstructed into 3D images using NEMOCEPH 3D software.

The most reliable landmark as described by Nechala et al.6, 7, 8 is termed as MAXILLOZYGION is the landmark taken to assess the malar prominence in 3 different spatial planes by using other different identified landmark which include FZS-frontozygomatic suture (the most anterior point of the frontozygomatic suture on the orbital rim), Z-the zygion (the most lateral point on the zygomatic arch), ANS-anterior nasal spine (the anterior tip of the sharp bony process of maxilla), ZM- zygomaxillare anterior (lowest point on the zygomaxillary suture) as seen in Figure 1.

Figure 1

Stable landmarks identified as 1. Fzs R(right), 2. ZR(right), 3. ZmR(right), 4,5. Ans, 6. Fzs L(left), 7. ZL(left), 8. ZmL(left)

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/43b59256-e5c5-4f93-bd88-c4207673dbd2/image/03521879-15ea-488d-abda-0f54e1ec1b75-uimage.png

The intersection point formed by Z-zygion, ANS-anterior nasal spine and FZS-frontozygomatic suture, ZM- zygomaxillare anterior is considered to be the constructed Maxillozygion point in this study[my] as shown in Figure 2.

Figure 2

Construction of maxillozygion point(my) by intersection of Z-the zygion, ANS-anteriornasal spine and FZS-frontozygomatic, ZM- zygomaxillare anterior

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/43b59256-e5c5-4f93-bd88-c4207673dbd2/image/199016cd-8471-4ea4-a437-8549aec03d5a-uimage.png

The actual Maxillozygion[mzy] is localized at the most prominent point on the maxillozygomatic suture line below the lateral third of the bony orbit as described by SAMI P. et al6, 7, 9 in their study as shown in Figure 3

Figure 3

Location of maxillozygion point (Mzy)

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/43b59256-e5c5-4f93-bd88-c4207673dbd2/image/6ef919a3-69af-4d9f-aae7-73d1ae517345-uimage.png

Also, for the accuracy of the constructed Maxillozygion point [my], the distance between the actual Maxillozygion [mzy] and constructed Maxillozygion [my] is measured and calculated between left and right side of males and females and the mean is calculated.

In the second part of the study Specific stable skeletal landmarks are taken. Using these landmarks, a patient-oriented axis system is centered to construct 3 different reference planes (X, Y, Z).

Nasion (N) was selected as the origin of the 3D coordinated system. The three reference planes are the mid-sagittal plane (X) passing through the S-N-Ba, the transverse plane (Y) passing through S-N and perpendicular to mid-sagittal plane, and the coronal plane (Z) passing through N and perpendicular to the other two planes. The distance from the maxillozygion [my] to the three reference planes (X, Y, Z) is measured in both the groups and the mean is calculated.

Results

Total Sample size of 42 is calculated by independent t tests (two groups), keeping the Effect size d of 0.70, α err at 0.05, power (1-β err prob)-0.80 and the allocation ratio at 1 (N2/N1).

In the present study there was an equal distribution of males and females with 50% [n=21] were been considered. In the Table 1, the mean values of the constructed anatomical landmark (maxillozygion) coordinated to X,Y,Z planes between right and left sides of the face is compared using student paired T test.

The point coordinates on the mid sagittal plane (X) on the right half of the face was 48.472±3.324mm whereas on the left half of the face was 48.378±3.124mm with a mean difference of 0.093mm and this difference was not statistically significant (p=0.75).

The point coordinates on the Axial plane (Y) on the right half of the face was 19.106±3.933mm whereas on the left half of the face is 19.221±4.354mm with a mean difference of -0.115mm and this difference was not statistically significant (p=0.67).

The point coordinates on the Coronal plane (Z) on the right half of the face was 38.143±4.989mm whereas on the left half of the face was 38.216±4.867mm with a mean difference of -0.073mm and this difference was not statistically significant (p=0.45).

There is no statistically significant differences in the point coordinates of midsagittal(X), Axial(Y) and Coronal(Z) plane for the right and left half of the face.

In the Table 2, the mean distance from Mzy and My between right and left half of the face was compared using student paired t- Test. The mean distance from Mzy and My on the right half of the face is 0.577±0.466mm with a mean difference of -0.039mm and on the left half of the face is 0.616±0.416mm with a mean difference of -0.039mm. There is no significant differences for the mean distance from Mzy and My for the right and left half of the face (p=0.35).

Table 1

Comparison of mean values of different parameters between riht & left sides using Student Paired t Test

Parameters

Sides

N

Mean

SD

Mean Diff

P-Value

Mid Sagittal

Right

42

48.472

3.324

0.093

0.75

Left

42

48.378

3.124

Axial

Right

42

19.106

3.933

-0.115

0.67

Left

42

19.221

4.354

Coronal

Right

42

38.143

4.989

0.073

0.45

Left

42

38.216

4.867

Table 2

Comparison of mean distance from MZY - MY between right & left sides using Student Paired t Test

Parameters

Sides

N

Mean

SD

Mean Diff

P-Value

Distance

Right

42

0.577

0.466

-0.039

0.35

Left

42

0.616

0.416

In the Table 3, the mean values of the constructed anatomical landmark (maxillozygion) coordinated to Mid sagittal(X), Axial(Y) and Coronal(Z) planes for both the genders (males and females) was compared using Independent Student t Test.

The point coordinated to Mid sagittal(X) plane for males was significantly higher (50.157±2.601mm) as compared to females (46.693±2.529mm) with a mean difference of 3.463mm and this difference was statistically significant (p<0.001).

The point coordinated to Axial (Y) plane for males was significantly higher (20.702±3.896mm) as compared to females (17.624±3.681mm) with a mean difference of 3.078mm and this difference was statistically significant (p=0.01).

The point coordinated to Coronal (Z) plane for males was significantly higher (39.545±5.312mm) as compared to females (35.862±3.524mm) with a mean difference of 3.682mm and this difference was statistically significant (p=0.01).

In the Table 4, the mean distance from Mzy and My between males and females is compared using Mann Whitney Test. The distance from Mzy and My for males was significantly higher (0.730±0.86mm) as compared to females (0.464±0.260mm) with a mean difference of 0.266mm and this difference was statistically significant (p=0.03).

Table 3

Gender wise comparison of mean values of different parameters using Independent Student t Test

Parameters

Gender

N

Mean

SD

Mean Diff

P-Value

Mid Sagittal

Males

21

50.157

2.601

3.463

<0.001*

Females

21

46.693

2.529

Axial

Males

21

20.702

3.896

3.078

0.01*

Females

21

17.624

3.681

Coronal

Males

21

39.545

5.312

3.682

0.01*

Females

21

35.862

3.524

[i] * - Statistically Significant

Table 4

Gender wise comparison of mean distance from MZY - MY using Mann Whitney Test

Parameters

Gender

N

Mean

SD

Mean Diff

P-Value

Distance

Males

21

0.730

0.486

0.266

0.03*

Females

21

0.464

0.260

[i] * - Statistically Significant

Discussion

The goal of any orthodontic treatment should include all the three aspects of jackson’s triad, like 1) structural balance, 2) functional efficiency 3) esthetic harmony.10 In recent years, esthetics has become the primary consideration for the patients seeking orthodontic treatment. Planning the treatment goals in order to achieve this aspect of structural balance should be of prime concern.

A combination of clinical and radiographic examinations is necessary to successfully diagnose and plan the treatment for any malocclusion and dentofacial deformity. Traditionally, many two-dimensional techniques were used to perform analysis, but they have inherent Limitations which include the superimposition of bilateral structural points, the magnification factor, and poor patient positioning.11

In an effort to overcome this limitation, the field of dentistry has evolved to another dimension by the introduction of advance radiological method i.e CBCT which is used to identify and quantify the characteristics of cephalometric variables assists clinicians in obtaining enhanced diagnosis and treatment planning.12

The present study concentrates on Malar prominence which is present on the zygomatic bone as an anterior protuberance. It is defined as maxillozygion which is localized at the most prominent point on the zygomaticomaxillary suture line below the lateral third of the bony orbit as described as SAMI P. et al.9 This landmark adds up to the esthetics of a perfectly balanced ideal face. Locating such a vital structure would help an orthodontist to carry out a perfect treatment planning and achieve ideal results. The present study describes malar prominence location which defines the face and helps in treatment planning of midface deficiencies.

Various two‑ dimensional facial analysis studies have been carried out to evaluate and diagnose malar deficiency. Hinderer13 placed different size malar implants on the plaster cast of a patient’s face to evaluate and determine the level of deficiency. Wilkinson14 drew a line from the outer canthus to the border of the mandible and stated that the malar eminence was located just posterior to that line. This technique was criticized as it could not define the relationship between the vertical line from the canthus and the intersection point with the mandible. In the study of Powell et al15 malar eminence was found to be 2–2.5 cm lateral to the lateral canthus of the eye. They concluded that “in patients with flat cheek bones laterally, or with full cheeks anteriorly, second to buccal fat, the exact eminence was difficult to establish.” In a study by Frey,16 the ideal projection of the cheek prominence was found to be approximately 2 mm beyond the anterior surface of the cornea in the sagittal plane along the Frankfurt horizontal plane. However, all these studies did not specify landmarks to describe the malar eminence and only spoke of these areas in general terms.

The landmarks referred in the present study for the location of malar prominence using CBCT are FZS, Z, ANS and ZM. FZS- Since the frontozygomatic suture is bilateral and the length of the bony projections is greatest near the center of the suture, in the present study, the centre of the suture is taken as a stable landmark.17 Z- It is the most commonly defined landmark on the temporal bone, also named the lateral or midzygomatic on the maximum horizontal and vertical outer curvature of the zygomatic arch Aulsebrook et al 18 (1996), so, this stable landmark was chosen for the present study to locate the malar eminence. ANS- The reason for using this landmark was the convenience in locating the anterior nasal spine in living subjects, thus resulting in a better clinical application of the data, thereby making the data derived by using this landmark would be more applicable to clinical settings.19, 20 ZM- it is the lowest point on the zygomaxillary suture by Hanihara21/Iscan and Steyn22 2013. Since the point lies inferior to zygomaticomaxillary suture, it is chosen as another stable landmark for this study.

In the study conducted by Sami P et al9 the anatomical landmark maxillozygion was identified and selected using CT by landmarks including fzs, zyg, and orbitale. But in the present study, the landmark was located using CBCT using the stable landmarks as shown in Figure 1. Three skeletal landmarks were used to produce a patient coordinated axis system in their study were: the nasion, subspinale and the basion. Where as in the present study, the orthogonal planes were constructed using Nasion (N) which was selected as the origin of the 3D coordinated system. The three reference planes are the mid-sagittal plane (X) passing through the S-N-Ba, the transverse plane (Y) passing through S-N and perpendicular to mid-sagittal plane, and the coronal plane (Z) passing through N and perpendicular to the other two planes. Erkan et al 23 studied the reliability of four different computerized cephalometric analysis programs and concluded that there is no statistically significant difference between the studied cephalometric analysis programs. Nemoceph software was used in the present study to analyse the CBCT data. The identified prevalence of constructed maxillozygion in the present study (p=0.35), is similar to the prevalence identified in the study by Nechela et al.8

When the comparision of mean values of parametres in all three orthogonal planes was done on both right and left half of the face, we have found most of the samples are symmetrical for midsagittal, axial and coronal planes and it is found to be not significant (Table 2). The present study results are similar to the study conducted by Nechela P et al.,8 where reliability of locating the landmark on both the sides of the face and he found that there was no difference on determining the data for position of the maxillozygion bilaterally.

In the study conducted by Jose J et al.,24 for validity of visual vector relationship for the clinical assessment of malar prominence, there was no statistically significant sexual dimorphism between the positive or negative vector groups, where as in the present study, there exists a sexual dimorphism, where the point coordinates on Mid sagittal plane(X), Axial(Y) and Coronal(Z) planes in males is higher than females and it is found to be statistically significant and also the mean distance between the Mzy and My is also higher in males when compared to females and its found to be statistically significant (p=0.03) (Table 4). In the study of Bozic M et al.,25 for facial morphology of Slovenian and welsh populations using 3-dimensional imaging concluded that there exists a morphological difference between Slovenian and welsh faces. So, the current study limited to bangalore population. There are no previous studies to localize the malar prominence using CBCT. Thus, an attempt has been made by using a novel method to localize the hard tissue maxillozygion using 3D CBCT for the defined population which will be helpful in orthodontic diagnosis and treatment planning for malar augmentation, camouflage treatment in subjects with midface deficiencies.

Source of Funding

None.

Conflict of Interest

None.

Acknowledgement

Department of orthodontics and dentofacial orthopaedics, Dayananda Sagar College of Dental Sciences, Bangalore, Karnataka Principal: Dr.Hemanth M. (Professor and Head of department) Department of Orthodontics & Dentofacial Orthopaedics. CBCT centre: Radiology Imaging Solutions, Bangalore, Karnataka.

References

1 

GM Doddamani PV Swathi KF Tan Assessment of anterior malar projection using visual photographs and lateral cephalograms: A comparative studyJ Orthod Sci201871510.4103/jos.JOS_30_18

2 

J Jomin N Nelivigi SS Pai V Pai AE Vishwanath M Prasad Validity of Visual Vector Relationship for the Clinical Assessment of Anterior Malar Projection and the Changes Observed in Facemask Therapy Patients - A Retrospective StudyIOSR J Dent Med Sci20161571438

3 

NO Wesley Anthropometric measurements of beauty and ethnic variationsJ Aesth Plast Surg200327397402

4 

M Bozic CH Kau S Richmond N Ihan Hren A Zhurov M Udovič Facial morphology of Slovenian and Welsh white populations using 3-dimensional imagingAngle Orthod20097946405

5 

B Trpkova P Major N Prasad B Nebbe Cephalometric landmarks identification and reproducibility: a meta-analysisAm J Orthod Dentofacial Orthop1997112216570

6 

A Muramatsu H Nawa M Kimura K Yoshida M Maeda A Katsumata Reproducibility of maxillofacial anatomic landmarks on 3-dimensional computed tomographic images determined with the 95% confidence ellipse methodAngle Orthod2008783396402

7 

ST Frey New diagnostic tenet of the esthetic midface for clinical assessment of anterior malar projectionAngle Orthod20138357904

8 

P Nechala J Mahoney LG Farkas Maxillozygional anthropometric landmark: a new morphometric orientation point in the upper faceAnn Plast Surg19984144029

9 

SP Moubayed F Duong C Ahmarani A Rahal A novel technique for malar eminence evaluation using 3-dimensional computed tomographyArch Facial Plast Surg2012146403710.1001/archfacial.2012.510.

10 

MB Asbell A brief history of orthodonticsAm J Orthod Dentofacial Orthop199098217683

11 

S Kapila RS Conley WE Harrell The current status of cone beam computed tomography imaging in orthodonticsDentomaxillofac Radiol2011401243410.1259/dmfr/12615645

12 

WC Scarfe B Azevedo S Toghyani AG Farman Cone beam computed tomographic imaging in orthodonticsAust Dent J2017623350

13 

UT Hinderer Malar implants for improvement of the facial appearancePlast Reconstr Surg1975561576510.1097/00006534-197508000-00007

14 

TS Wilkinson Complications in aesthetic malar augmentationPlast Reconstr Surg1983715643910.1097/00006534-198305000-00011

15 

NB Powell RW Riley DR Laub A new approach to evaluation and surgery of the malar complexAnn Plast Surg19882020614

16 

ST Frey New diagnostic tenet of the esthetic midface for clinical assessment of anterior malar projectionAngle Orthod20138357904

17 

VG Kokich Age changes in the human frontozygomatic suture from 20 to 95 yearsAm J Orthod197669441130

18 

WA Aulsebrook PJ Becker MY İşcan Facial soft-tissue thicknesses in the adult male ZuluForensic Sci Int19967983102

19 

S Damas O Cordón O Ibáñez Relationships Between the Skull and the Face for Forensic Craniofacial SuperimpositionHandbook on Craniofacial Superimposition2020115010.1007/978-3-319-11137-7_3

20 

GB Hopkin Hypoplasia of the middle third of the face associated with congenital absence of the anterior nasal spine, depression of the nasal bones, and angle class III malocclusionBr J Plast Surg19631614653

21 

T Hanihara Frontal and facial flatness of major human populationsAm J Phys Anthropol2000111110534

22 

MY Iscan M Steyn The human skeleton in forensic medicineCharles C Thomas Publisher20131

23 

M Erkan HG Gurel M Nur B Demirel Reliability of four different computerized cephalometric analysis programsEur J Orthod201234331821

24 

J Jose Validity of Visual Vector Relationship for the Clinical Assessment of Anterior Malar Projection and the Changes Observed in Facemask Therapy Patients - A Retrospective StudyIOSR J Dent Med Sci20161571438

25 

M Bozic Facial Morphology of Slovenian and Welsh White Populations Using 3-Dimensional ImagingAngle Orthod2009796405



jats-html.xsl

© This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Article type

Original Article


Article page

223-228


Authors Details

Hemanth M, Sanda Aamani*, Sharmada B K, Karthik J Kabbur, Goutham Kalladka


Article History

Received : 23-06-2021

Accepted : 07-09-2021

Available online : 22-10-2021


Article Metrics


View Article As

 


Downlaod Files

   








Open Abstract (Increase article citation) Wiki in hindi