|Year : 2021 | Volume
| Issue : 1 | Page : 20-27
Orthognathic cephalometric norms for a sample of Sudanese adults
Wadie Magdi Gilada, Amal Hussien Abuaffan, Marwa Mahmoud Hamid
Department of Orthodontics, Pedodontics and Preventive Dentistry, Faculty of Dentistry, University of Khartoum, Khartoum, Sudan
|Date of Submission||17-Feb-2021|
|Date of Decision||20-Feb-2021|
|Date of Acceptance||23-Feb-2021|
|Date of Web Publication||29-Jun-2021|
Marwa Mahmoud Hamid
Department of Orthodontics, Pedodontics and Preventive Dentistry, Faculty of Dentistry, University of Khartoum, P. O. Box: 11115, Khartoum
Source of Support: None, Conflict of Interest: None
Background: With the recent global increase in the number of adult patients seeking orthodontic treatment in general and orthognathic surgery in specific, the need for population-specific cephalometric norms emerges. This is essential in diagnosing and formulating more optimum treatment plans. Aim: To establish orthognathic cephalometric standard values for an sample of Sudanese Adults. Design: Cross-sectional observational analytical study. Materials and Methods: A total of 106 cephalometric radiographs of Sudanese adults aged between 17 and 25 years (48 males and 58 females) were digitally traced and analyzed using Burstone's Cephalometric for Orthognathic Surgery analysis (COGS). Statistical Analysis: Descriptive statistics, means, and standard deviations were used to present Sudanese standard values. Paired sample t-test was used to test for significant differences between Sudanese and Caucasian norms. Results: When compared to European–Americans, Sudanese adults, in general, had a shorter cranial base, lower values of some vertical height measurements, shorter maxillae, and larger mandibular plane angle. In addition, Sudanese females had a more convex profile and more protrusive maxillae in comparison to their European–Americans counterparts. Regarding dental measurements, Sudanese males had statistically significant lower values of upper and lower anterior and posterior dental heights, steeper occlusal plane, and more proclined incisors. Moreover, Sudanese females had steeper occlusal plane as well as more proclination of the anterior teeth when compared to their European–American counterparts. Conclusions: Considerable differences in skeletal and dental configuration exist between Sudanese and European-American adults. These variations must be considered during treatment planning. This study can provide a useful database for orthognathic surgery treatment planning for Sudanese adults.
Keywords: Norms, orthognathic, Sudanese
|How to cite this article:|
Gilada WM, Abuaffan AH, Hamid MM. Orthognathic cephalometric norms for a sample of Sudanese adults. J Head Neck Physicians Surg 2021;9:20-7
|How to cite this URL:|
Gilada WM, Abuaffan AH, Hamid MM. Orthognathic cephalometric norms for a sample of Sudanese adults. J Head Neck Physicians Surg [serial online] 2021 [cited 2021 Jul 27];9:20-7. Available from: https://www.jhnps.org/text.asp?2021/9/1/20/319741
| Introduction|| |
Angle defined malocclusion as the deviation from ideal occlusion, which can be treated by orthodontic removable or fixed appliances.
However, some malocclusions have a large skeletal component in their etiology and cannot be properly managed by dental camouflage alone. In these circumstances, the proper management is by growth modification for growing patients or by a combined orthodontic surgical approach for nongrowing patients. Orthognathic surgery aims to achieve the best functional, anatomical, and esthetic results.,,
Recent dramatic advancements in the field of orthognathic surgery have raised the possibility for many sever problems, that were untreatable a few years back to be solved surgically, these include modern equipment, technology, and hospital facilities.
Burstone et al. developed a cephalometric analysis specifically for European–American patients undergoing orthognathic surgery.
Since Sudanese adults have different facial characteristics from Caucasians, the need to have cephalometric standards specific to Sudanese emerges. In the previous literature, numerous studies had been carried out to establish the normal cephalometric measurement for orthognathic surgery among different populations.,,,,,,, However, no such study had been conducted among the Sudanese population. Therefore, this study is intended to establish cephalometric measurements for orthognathic surgery in a sample of Sudanese adults.
| Materials and Methods|| |
A hundred and six lateral cephalometric radiographs of Sudanese adults with normal occlusion (48 males and 58 females) aged between 17 and 25 years were selected. The inclusion criteria were as follows: (1) Sudanese nationality adults, (2) Class I normal occlusion with average horizontal and vertical overbite, (3) well-aligned teeth with less than 2 mm irregularity, and (4) no current or previous history of facial deformity or orthodontic treatment. Data were collected from the orthodontic department archive of a public university. Ethical approval was obtained from the Ethics Research Committee of the university.
All lateral cephalograms were taken in the natural head position with maximum intercuspation and relaxed lips.
All radiographs were digitally traced according to Burstone's et al. Cephalometric for Orthognathic Surgery Analysis (COGS) using (vistaDent OCTM–version 4.2.61 (177) ©2006–GAC International, Inc.) computer software program.
Reference landmarks and planes used are listed in [Table 1] and described in [Figure 1].
|Table 1: Landmarks and reference planes used in cephalometric for orthognathic surgery|
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|Figure 1: Landmarks and reference planes: N: Nasion, S: Sella, A: Subspinale, B: Supramentale, ANS: Anterior nasal spine, PNS: Posterior nasal spine, PTM: Pterygomaxillary fissure, Ar: Articulare, Go: Gonion, Me: Menton, Gn: Gnathion, Pg: Pogonion, SN: SN plane, HP: True horizontal plane, NF: Nasal floor, OP: Occlusal plane, MP: Mandibular plane|
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The collected data were analyzed using the Statistical Package for Social Sciences (SPSS, version 21.0 for Windows, SPSS Inc., Chicago, Illinois, USA). For determining intraclass reliability, a paired sample t-test was performed on two sets of measurements recorded 2 weeks apart for 20% of the sample carried out by the main investigator.
Differences between Sudanese sample and Burstone et al. sample and also between Sudanese males and females were studied by applying Independent sample t-test. P value was set at the 0.05 level for all tests.
| Results|| |
Intraclass reliability testing showed no statistically significant difference between the two readings for all study variables [Table 2]. The results of the descriptive statistics for the cephalometric values of Sudanese adults compared to European–Americans are shown in [Table 3] and [Table 4]. The comparison between Sudanese males and females' measurements is in [Table 5].
|Table 3: Comparison of cephalometric norms between sudanese and caucasian males group using cephalometric for orthognathic surgery|
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|Table 4: Comparison of cephalometric norms between Sudanese and Caucasian female group using cephalometric for orthognathic surgery|
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|Table 5: Comparison of cephalometric values of Sudanese males and females using cephalometric for orthognathic surgery|
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| Discussion|| |
Recently, the demand for orthodontic treatment is on the rise, with orthognathic surgery becoming an option for many patients with severe malocclusion, that requires proper diagnosis and treatment planning, where cephalometric analysis acts as an important tool in planning orthognathic surgery.
This is a cross-sectional descriptive study carried out on Sudanese adults with normal occlusion (17–25 years) cephalometric radiographs, for establishing standard values required for orthognathic surgery planning.
Burstone's hard tissue analysis (COGS) was chosen in this study because it depends on linear and angular measurements essential for the diagnosis and treatment planning of the orthognathic surgery, describes the size and position of facial bones and associated structure. Most surgeons think in terms of millimeters. Therefore, it is a practical and accurate analysis.
The measurements in this analysis are discussed in five main categories: Cranial base, horizontal measurements, vertical measurements, maxillary and mandibular measurements, and dental measurements.
Cranial base [Figure 2]
|Figure 2: Cranial base measurements are made parallel to HP: Posterior cranial base length (Ar-PTM), anterior cranial base length (PTM-N)|
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Cranial base length, especially the posterior component signifies the position of the mandible in relation to the maxilla; greater values denote the more posterior position of the mandible. Sudanese males had shorter anterior and posterior cranial base lengths (49.74 mm and 31.19 mm), respectively, when compared to European–American males. While females had similar anterior cranial base length to European–American females and shorter posterior cranial base length when compared to European–American females. These differences may be due to ethnic and genetic variations.
No statistically significant difference was detected in cranial base length between Sudanese males and females.
Horizontal skeletal measurement [Figure 3]
|Figure 3: Horizontal skeletal measurements: (1) facial convexity angle: The angle between the NA line and APg line.(2), (3) and (4) maxillary, mandibular, and chin protrusion: Distance from A, B, and Pg to N measured parallel to HP, respectively|
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The present study did not reveal any significant difference between Sudanese and European American males in any of the horizontal parameters; convexity angle, maxillary, mandibular, and chin protrusion. On the contrary, Sudanese females had more convex profiles than their Caucasian counterparts (7.4° and 2.6°), respectively. This variation can be partially attributed to the difference in Point A position or soft tissue thickness between the two samples.
Sudanese males and females had more or less similar horizontal configuration except in chin protrusion where it was larger in males than females (−3.23 mm and − 6.2 mm) respectively.
Vertical skeletal measurement [Figure 4]
|Figure 4: Vertical skeletal measurement: N-ANS: Upper anterior facial height, ANS-Gn: Lower anterior facial height, N-PNS: Upper posterior facial height, MP-HP angle: Mandibular plane angle|
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The vertical dimensions of Sudanese males were significantly different from that of European–Americans. Sudanese had shorter upper anterior, lower anterior, and upper posterior facial heights (49.1 mm, 64.5 mm, and 49.11 mm), respectively. However, Sudanese males had a steeper mandibular plane angle (25.1°) compared to (23°) in Burstone's sample.
In the female groups, Sudanese had shorter upper posterior facial height (48.6 mm) compared to (50.6 mm) in Caucasian. In addition, Sudanese females had a larger mandibular plane angle than Caucasian females (28.5°, 24°), respectively.
In the current results, the horizontal plane mandibular plane angle was increased significantly in females than males (P = 0.006).
These differences in results might be due to ethnic background which affects the position of Nasion, downward upward rotation of the maxilla, and short posterior facial height as explained by Alcalde et al.
Maxillary and mandibular measurements [Figure 5]
|Figure 5: Maxilla and Mandible measurements: ANS-PNS measured parallel to HP: Maxillary length. Ar-Go: Mandibular ramus length. Go-Pg: Mandibular body length. B-Pg: Chin depth measured as the distance from B to a line perpendicular to MP and passing through Pg. Ar-Go-Gn: Gonial angle|
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Most of the parameters in this group showed a significant difference between Sudanese and European Americans in both gender groups. Sudanese males had lower values of maxillary length, ramus length, mandibular body length, and chin depth (49.6 mm, 44.1 mm, 77.1 mm, and 4.9 mm), respectively, when compared to European-Americans (57.5 mm, 52 mm, 83.7 mm, and 8.9 mm), respectively.
On the other hand, Sudanese females had shorter maxillae and mandibular rami and shallower chins (50 mm, 42.6 mm, and 4.9 mm) when matched to Burstone's females (52.5 mm, 46.8, and 7.2 mm), respectively. However, Sudanese females had longer mandibular bodies (77.2 mm) compared to European-American females (74.3 mm).
In the current study, no statistically significant difference was detected between males and females in all of the maxillary and mandibular measurements.
Dental measurements [Figure 6] and [Figure 7]
|Figure 6: Dental height measurements: (1) Upper anterior dental height: Perpendicular distance from upper incisor crown tip to the nasal floor NF. (2) Lower anterior dental height: Perpendicular distance from lower incisor crown tip to the mandibular plane MP. (3) Upper posterior dental height: Perpendicular distance from upper first molar mesiobuccal cusp tip to the nasal floor NF. (4) Lower posterior dental height: Perpendicular distance from lower first molar mesiobuccal cusp tip to the mandibular plane MP|
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|Figure 7: (1) Occlusal plane angle: The angle between the occlusal plane OP and horizontal plane HP. (2) Upper incisor inclination: The angle between the long axis of the upper incisor and nasal floor NF. (3) Lower incisor inclination: The angle between the long axis of the lower incisor and mandibular plane MP|
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Upper anterior dental height evaluates the total vertical dimensions of premaxilla from the nasal floor perpendicularly to the tip of the maxillary incisor crown. Whereas the posterior dental height aims to evaluate the posterior dental maxillary vertical height, i.e., the extent of the molar eruption.
Both of these values are significantly lower in Sudanese males (27.96 mm and 22.74 mm), respectively, when compared to Caucasian males (30.5 mm and 26.2 mm), respectively. This can be partially attributed to the increased dental protrusion of Sudanese males in relation to their Caucasian counterparts. However, Sudanese females had longer upper anterior dental height than Caucasians (28.7 mm and 27.5 mm), respectively, and shorter upper posterior dental height than Caucasians (22.4 mm and 23 mm), respectively.
Lower anterior dental height represents the total vertical dimension of anterior mandible from the mandibular plane perpendicularly to the tip of the lower incisor crown. It denotes how far the incisor has erupted in relation to their basal bone. It is remarkably shorter in Sudanese males (41.72 mm) than Caucasians (45 mm).
The lower posterior dental height measures the degree of lower molars eruption in relation to the mandibular plane. Similarly, it was less in Sudanese males (32.78 mm) compared to (35.8 mm) in Caucasians.
The occlusal plane angle is the angle between the occlusal plane and the horizontal plane. It signifies the steepness of the occlusal plane. The increase in occlusal plane angle can be associated with skeletal open bite, lip incompetence, increased facial height, and mandibular retrognathia. On the other hand, the decrease in this angle could result in a deep bite, decreased facial height, and lip redundancy. In the current sample, both males and females had larger values (8.5° and 10.6°), respectively, in relation to European males and females (6.1° and 7.1°). The variation in these results could be attributed to the variation of locating the occlusal plane or to the difference of the extent of molars and incisors eruption.
Upper incisor inclination is the angle formed between the upper incisor long axis and the nasal floor it is a useful measure to assess the procumbence of upper incisor as well as the long term stability of dentition. Sudanese males and females had more proclined upper incisors (118° and 116.4°), respectively, in comparison to Caucasian males and females (100.7° and 99.5°), respectively.
Similarly, lower incisor inclination is the angle formed between the lower incisor long axis and the mandibular plane. It signifies the procumbence of the lower incisor and the long term stability of tooth movement. Sudanese males and females had more proclined, lower anterior (107° and 99.5°), respectively, in comparison to Caucasian males and females (95.9° and 95.9°), respectively. These findings are consistent with the results of a previous study of Sudanese facial and dental characteristics using Arnett's soft-tissue cephalometric analysis.
When comparing the results of Sudanese males and females' cephalometric standards, it was found that the only statistically significant difference was in the occlusal plane angle. Males had a steeper occlusal plane (10.6°) compared to females (8.5°).
| Conclusions|| |
- The studied sample had its own unique facial characteristics that are significantly different from that of European–American adults in many skeletal parameters. Namely: Posterior cranial base length, upper posterior facial height, mandibular plane angle, maxillary length, ramus length, mandibular body length, and chin depth. Moreover, statistical significant differences were detected between Sudanese and European–American adults in all dental measurements
- Sudanese males had remarkably more prominent chin, more acute mandibular plane angle, and steeper occlusal plane in comparison to females
- Racial and ethnic differences in the skeletal and dental configuration of individuals must be taken into account when planning orthognathic surgery.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
This material has never been published and is not currently under evaluation in any other peer reviewed publication.
The permission was taken from Institutional Ethics Committee prior to starting the project. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]