Home Print this page Email this page Small font size Default font size Increase font size   Users Online: 471
Home About us Editorial board Search Browse articles Submit article Instructions Subscribe Contacts Login 


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 3  |  Issue : 3  |  Page : 74-80

Evaluation of relationship between cranial base angle and maxillofacial morphology in Indian population: A cephalometric study


1 Department of Orthodontics, Government Dental College and Hospital, Ahmedabad, Gujarat, India
2 Department of Orthodontics, College of Dental Sciences and Research Center, Ahmedabad, Gujarat, India
3 Department of Orthodontics, AMC Dental College and Hospital, Ahmedabad, Gujarat, India
4 Department of Orthodontics, Ahmedabad Dental College and Hospital, Ahmedabad, Gujarat, India

Date of Web Publication29-Jul-2014

Correspondence Address:
Dr. Nishit Mehta
1, Gyandip Society, Dhumketu Road, Paldi, Ahmedabad - 380 007, Gujarat
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2278-0203.137691

Rights and Permissions
  Abstract 

Objective : To investigate the role played by the cranial base flexure in influencing the sagittal and vertical position of the jaws in Indian population.
Materials and Methods : Lateral cephalograms of 108 subjects were divided into three categories (Group A: NSAr > 125°, Group B: NSAr-120°-125°, Group C: NSAr < 120°) according to value of NSAr. Measurement of eight angular (SNA, SNB, NPg-FH, ANB, NAPg, SN-GoGn, Y-Axis, ArGo-SN) and seven linear (N-S, S-Ar, Ar-N, Ar-Pt A, Ar-Gn, Wits appraisal, N- Pt A) variables were taken.
Results : Pearson correlation coefficient test was used to individually correlate angular and linear variables with NSAr for the whole sample as well as in individual group. Unpaired t-test was used to analyze the difference in the means of all the variables between the three groups. Significance was determined only when the confidence level was P < 0.05. Several parameters (SNB, NAPg, ANB, Y-Axis, GoGn-SN) showed significant positive correlation while others showed negative correlation (SNA, NPg-FH, N-S) with NSAr.
Conclusions : This study show cranial base angle has a determinant role in influencing the mandibular position and it also affects both the mandibular plane angle and y-axis. Flattening of the cranial base angle caused a clockwise rotation of the mandible. The jaw relation tends to change from class III to class II, with progressive flattening of the cranial base and vice-versa.

Keywords: Cranial base angle, lateral cephalogram, maxilla-mandibular relationship, skeletal pattern, treatment planning


How to cite this article:
Bhattacharya A, Bhatia A, Patel D, Mehta N, Parekh H, Trivedi R. Evaluation of relationship between cranial base angle and maxillofacial morphology in Indian population: A cephalometric study. J Orthodont Sci 2014;3:74-80

How to cite this URL:
Bhattacharya A, Bhatia A, Patel D, Mehta N, Parekh H, Trivedi R. Evaluation of relationship between cranial base angle and maxillofacial morphology in Indian population: A cephalometric study. J Orthodont Sci [serial online] 2014 [cited 2020 May 29];3:74-80. Available from: http://www.jorthodsci.org/text.asp?2014/3/3/74/137691


  Introduction Top


The cranial base area of the craniofacial complex has long been of interest to orthodontists and craniofacial anthropologists. Young, [1] as early as 1916, recognized relationship between cranial base morphology and prognathism of the jaws. After the birth of a child, cranial base angle has a tendency to reduce with age. In their study Moss and Greenberg, [2] Scott, [3] Stramrud, [4] Melson, [5] Ohtsukhi et al. [6] they have found that the measure of cranial base angle stabilizes between 5 and 7 years and there after any change is hardly noticed in its value. The maxilla appears to be attached to the anterior segment and the mandible to the posterior segment of the cranial base. The consensus of different authors such as Renfroe, [7] Bjork, [8] Coben, [9] Moss, [10] and Hopkin [11] proved that the cranial base morphology has considerable influence upon the position of maxilla and mandible, thus determining the skeletal pattern of an individual. The increase in the flexion of the cranial base would increase Class-III tendency, while the reduction in the flexion of the cranial base would increase Class-II tendency. Thus, it should be of great help for an orthodontist to predict the future skeletal pattern of a child from the value of cranial base angle at an early age.

However, it is noticed that most of the workers had collected and grouped their samples according to the skeletal jaw relationship and then had tried to assess and compare the values of cranial base angle of each skeletal group. Very few studies are carried out to assess the skeletal jaw pattern of individuals having different values for their saddle angle.

Thus in view of above facts, a cephalometric study is conducted with following aims and objectives to explore the relationship between the cranial base angle and the maxillofacial morphology.

  1. To estimate the values of different craniofacial skeletal parameters for individuals having varied range of cranial base angle
  2. To compare and correlate the value of cranial base angle with eight angular and seven linear parameters in different groups
  3. To compare and correlate the value of cranial base angle with eight angular and seven linear parameters for overall data
  4. To find the difference in the values of all the parameters between groups having varied range of cranial base angle.



  Materials and Methods Top


Materials

For this study, sample consisting of 108 lateral cephalograms are collected from the records of the patients reported at the Department of Orthodontics, Government Dental College and Hospital, Ahmedabad, on the basis of following criteria:

  1. None of the subjects had undergone orthodontic treatment in the past
  2. The age range of the subject was between 12 and 16 years
  3. There was no facial disharmony whatsoever due to any systemic problem or any major accident in the past affecting the bones of the facial skeleton.


Methods

Once the lateral cephalograms are collected, estimation of the values of cranial base angle is done for each case. On the basis of their values, the total sample is divided into three categories:

  • Group A: NSAr > 125° (n = 33)
  • Group B: NSAr-120°-125° (n = 30)
  • Group C: NSAr < 120° (n = 45)


In this study, for the purpose of estimating the degree of flexure of the cranial base angle (NSAr), point "Articulare" rather than "Basion" has been used to represent the posterior extent of the cranial base. It is proved by Bhatia and Leighton [12] that the growth patterns studied by use of Basion or Articulare, are very similar.

Further cephalometric points [Table 1] are plotted, lines [Table 2] and angles [Table 3] are drawn. Eight angular (SNA, SNB, NPg-FH, ANB, NAPg, SN-GoGn, Y-axis, ArGo-SN) and seven linear (N-S, S-Ar, Ar-N, Ar-Pt A, Ar-Gn, Wits appraisal, N-Pt A) parameters are recorded for carrying out necessary statistical analysis. The above measurements are selected primarily to investigate the role played by the cranial base flexure in influencing the sagittal and vertical position of the jaws.
Table 1: Points

Click here to view
Table 2: Lines

Click here to view
Table 3: Angles and measurements

Click here to view


Statistical Analysis

We performed statistical analysis using the Microsoft Office Excel 2007 and IBM SPSS version 22 software. Various angular and linear variables were measured and their mean and standard deviations were calculated in all the three groups as shown in [Table 4].
Table 4: Mean and SD of all parameters in three groups

Click here to view


All the variables were then individually correlated with NSAr for the whole sample as well as in individual group using Pearson correlation co-efficient test. Unpaired t-test was then used to analyze the difference in the means of all the variables between the three groups.


  Results Top


[Table 5] shows the frequency of observations for each values of angle NSAr in the total sample and corresponding mean values of angle SNA. The co-efficient correlation value for their comparison reveals a highly significant negative correlation between the two angles (r = −0.3667/P < 0.001). When similar comparison is carried out group wise, as shown in [Table 6], a negative correlation is seen in all the groups, however it is statistically significant for Groups A (r = −0.2907/P = 0.023) and C (r = −0.5590/P = 0.001), but not for Group B (r = −0.1641/P = 0.386). [Table 5] shows co-efficient correlation value for comparison between angles SNB and angle NSAr in the overall data. It shows a highly significant negative correlation between the two angles (r = −0.6483/P < 0.001). The cranial base angle seemed to influence the mandible more than the maxilla as revealed by a stronger negative correlation between angle SNB and NSAr than with angle SNA in the overall sample. [Table 6] which is showing comparison between the two angles in individual groups, show a significant negative correlation in Groups A (r = −0.3803/P = 0.003) and C (r = −0.4196/P = 0.022) but not in Group B (r = −0.1903/P = 0.314), which might be due to the small range of angle NSAr for this group. A correlation of greater significance level, between the two angles, is seen in Group A. [Table 6] suggests significant negative correlation between NPg-FH and NSAr in the overall data (r = −0.308/P = 0.001). However, comparison between the individual groups revealed a nonsignificant negative correlation between the two angles as shown in [Table 6]. From [Table 5], (correlating angle ANB with angle NSAr), [Table 5] (correlating angle NAPg with angle NSAr) and [Table 5] (correlating Wits appraisal with angle NSAr); each reveals highly significant positive correlation of each of these parameters when compared with angle NSAr for the overall sample (r = −0.308/P = 0.001), (r = 0.5059/P < 0.001), (r = 0.5430/P < 0.001). From [Table 6] one can assess the behavior of individual parameters within the different groups when compared to angle NSAr. It shows significant positive correlation between angle NSAr and these three parameters, suggesting sagittal positioning of the jaws in Group B only (r = 0.4785/P = 0.006), (r = 0.3885/P = 0.011), (r = 0.4574/P = 0.002). In this study as shown in [Table 5], the mandibular plane angle as well as Y-axis angle shows a positive correlation with angle NSAr in the overall sample (r = 0.1863/P = 0.041), (r = 0.2713/P = 0.003), however the level of significance of correlation is much higher for Y-axis angle than for GoGn-SN angle. The same relationship when assessed in between the groups, as shown from [Table 6], no significant correlation is found at any level. However when values of Y-axis angle and GoGn-SN angle were compared for different groups by t-test, no differences are found when Group B is compared with Groups A and C, but when compared to Group A, Group C differs significantly for Y-axis only. The anterior cranial base (N-S) shows a negative nonsignificant correlation with angle NSAr in the overall sample as well as when compared in individual group [Table 5] and [Table 6]. Similar are the finding for the posterior cranial base (S-Ar) [Table 5] and [Table 6]. Furthermore, differences in the values of the above parameters between groups are not significant as per t-test [Table 7]. However as shown from, [Table 5], the total cranial base length (Ar-N) have significant positive correlation with angle NSAr in the overall sample (r = 0.268/P = 0.003). Furthermore, [Table 6] shows significant positive correlation between the two parameters in Group A, (r = 0.3749/P = 0.004). When mean values for length Ar-N is compared by t-test, [Table 7], significant difference is found between Groups A and C. As shown in [Table 5], Maxillary length showed a significant positive correlation with cranial base angle in the overall sample (r = 0.2853/P = 0.002). The maxillary length progressively increases with an increase in the cranial base angle [Table 4] thus compensating for increase in its value. This increase in the maxillary length was significant between the Groups A and C, [Table 7]. Now when the maxillary position is evaluated by the method suggested by McNamara (measuring the linear distance of point A, from a perpendicular dropped from nasion to FH plane) and is correlated with NSAr, then no significant correlation is established [Table 5] and [Table 6]. Thus changes in NSAr do not affect N-pt A in this study. When mandibular length (Ar-Gn) is correlated with NSAr angle [Table 5] and [Table 6], an insignificant negative correlation is seen both in the overall data and in the individual groups. The inclination of the posterior border of the ramus (ArGo-SN) is correlated with angle NSAr [Table 5] and [Table 6] where no significant correlation is found.
Table 5: Reltionship between NSAr and other parameters in total sample

Click here to view
Table 6: Relationship between angle NSAr and various parameters in individual groups

Click here to view
Table 7: t-test to find significance of difference in the values of all the variables in the three groups

Click here to view



  Discussion Top


In this study, lateral cephalograms of 108 subjects were divided into three categories according to the values of angle NSAr of each subject as studies, which have found the skeletal pattern based on the cranial base angle are few. [13],[14],[15],[16] This study shows that as the cranial base angle reduces, the maxilla tends to protrude and angle SNA increases [Table 4], [Table 5] and [Table 6]. This is in agreement with the studies by Hopkin et al., [13] Varjanne and Koski, [14] Järvinen, [15] Moyers, [17] Enlow, [18] Profitt and Fields, [19] Kasai et al. [16] However, from [Table 7], when differences in the values of angle SNA were compared between Groups A, B and C; significant differences were not seen at any level. This concludes that though a significant negative correlation exists between these two angles, the sagittal position of maxillary apical base as described by point A is not highly affected.

It is clear as the cranial base angle reduces, the mandible tends to protrude, and angle SNB increases [Table 4], [Table 5] and [Table 6]. Moreover, as the cranial base angle reduces, the chin tends to protrude [Table 4], [Table 5] and [Table 6]. Further, differences in the values of angle SNB and NPg-FH when compared between the Groups A, B and C [Table 7], shows that significant differences exist in the measure of these angles between the groups with extreme ranges of the cranial base angle (Groups A and C). It can be concluded that mandibular position is affected to a great extent by the changes in the cranial base angle.

The above correlation suggests a relationship between the magnitude of the cranial base flexure and mandibular position. The smaller the cranial base angle, the more forward the mandibular position which increases the tendency to a Class-III jaw relationship and larger the cranial base angle, the more backward the position of the mandible, which increases the tendency to a Class-II jaw relationship. Also in contrast to maxilla, the mandible is affected more by changes in the cranial base angle. The above findings are in agreement with those of Kasai et al. [16] and Bjork, [20] who demonstrated the relationship between the cranial base angle and mandibular position and Baccetti et al., [21] who showed that the temporomandibular joint position was more posterior in skeletal Class-II than skeletal Class-III.

In order to assess the influence of saddle angle on maxillo-mandibular relationship, three parameters were studied, the ANB angle, Wits appraisal and angle of convexity (N-A-Pg). The observed correlation between the cranial base angle and the above parameters suggest that the opening of the cranial base flexure can result in a skeletal Class-II jaw relation and the closing of the cranial base flexure can result in a skeletal Class-III jaw relation. In this study the mean values of angle ANB, wits and angle N-A-Pg in the three groups support the above contention [Table 4]. When the values of ANB angle, wits, NAPg angle were compared in individual groups using the t-test, significant differences were seen between Groups A and C. The above findings support the work of Kerr and Hirst [22] who suggested that the cranial base angle at 5 years of age determines the fundamental jaw relationship and is an accurate predictor of ultimate facial type at 15 years of age. Anderson and Popovich [23] found more Class-II occlusions in large cranial base angle subjects. Kerr and Adams [24] concluded that the size and shape of the cranial base influences mandibular position by determining the anterioposterior position of the condyles relative to the facial profile. Enlow, [18] Harris et al., [25] Bacon et al. [26] have reported that the cranial base angle to be larger in Class-II subjects. However, according to Varrela, [27] early characteristics of a sample of Class-II occlusion patients found no cranial base etiology in the Class-II group. Kerr et al. [28] compared the cranial base in Class-I and Class-II skeletal patterns and found no significant differences between the skeletal classes for any of the cranial base measurements.

In this study subjects with most closed cranial base angle had a skeletal Class-III jaw relationship [Table 4]. This supports the findings of Enlow [18] but contradicts the findings of Anderson and Popovich [23] According to Anderson and Popovich [23] Class-III occlusion in subjects do not have the most closed cranial base angles.

To study the influence of cranial base angle on the rotation of the mandible, angle NSAr was correlated with Y-axis and mandibular plane angle (SN-GoGn). Correlation suggest that increase in the cranial base flexure can cause a clockwise rotation of the mandible [Table 5] and [Table 6]. The above findings are in agreement with those of Klocke et al. [29]

In this study, it is found that changes in the cranial base angle are independent of anterior as well as posterior cranial base length [Table 5], [Table 6] and [Table 7]. However, increase in the cranial base angle has high association with increase in the overall cranial base length and this tendency is greater near the upper extremities of cranial base angle [Table 5], [Table 6] and [Table 7]. Weidenreich [30] stated that the deflection of the cranial base shortened the nasion-basion line (overall cranial base), this correlates well with the present study in which the total cranial base length decreased significantly with a decrease in the cranial base angle [Table 5] and [Table 6].

An interesting association is seen between the cranial base angle and maxillary length. The maxillary length progressively increases with an increase in the cranial base angle [Table 4], thus compensating for increase in its value. This increase in the maxillary length was significant between the Groups A and C [Table 7]. Now when the maxillary position is evaluated by the method suggested by McNamara (measuring the linear distance of point A, from a perpendicular dropped from nasion to FH plane) and is correlated with NSAr, then no significant correlation is established [Table 7]. Thus changes in NSAr do not affect N-pt A in this study.

When mandibular length (Ar-Gn) was correlated with NSAr angle [Table 5] and [Table 6], an insignificant negative correlation is seen both in the overall data and in the individual groups. This suggest that the increase in the value of saddle angle, which has the tendency to cause retrusion of mandible is not being compensated by the mandibular length and this is the cause that the values of angle SNB and angle NPg-FH is influenced to a greater extent as compared to the values of angle SNA and N-PtA.

No significant correlation was found between inclination of the posterior border of the ramus (ArGo-SN) and NSAr, [Table 5]. This suggests that with increase in cranial base angle, which tends to position the head of the condyle more posteriorly, there is no compensation from the slope of the ascending ramus to bring the angle of mandible, or body, or chin forward.


  Conclusion Top


It has been known for a long time that the cranial base angle influences the craniofacial morphology. Based on this study, following conclusions are drawn:

  • The cranial base has definite influence on the maxilla. As the cranial base angle reduces, the maxilla tends to protrude and angle SNA increases.
  • The mandibular position is influenced to a greater extent by the cranial base angle than maxillary position. Cranial base angle has a determinant role in influencing the mandibular position.
  • The flattening of the cranial base angle causes a clockwise rotation of the mandible.
  • The jaw relation tends to change from Class-III to Class-II, with progressive flattening of the cranial base and vice-versa.


 
  References Top

1.Young M. A contribution to the study of Scottish skull. Trans R Soc Edin 1916;51:347-453.  Back to cited text no. 1
    
2.Moss M, Greenberg SN. Post natal growth of the human skull base. Angle Orthod 1955;25:77-84.  Back to cited text no. 2
    
3.Scott JH. The cranial base. Am J Phys Anthropol 1958;16:319-48.  Back to cited text no. 3
[PUBMED]    
4.Stramrud L. The pattern of craniofacial associations. Acta Odontol Scand 1959 ;24 Suppl 46:1-174.  Back to cited text no. 4
    
5.Melson B. The cranial base. The postnatal development of the cranial base studied histologically on human autopsy material. Acta Odontol Scand 1974;32 Suppl 62:1-126.  Back to cited text no. 5
    
6.Ohtsukhi F, Mukherjee D, Lewis AB, Roche AF. Growth of the cranial base and vault dimensions in children. J Anthropol Soc Nippon 1982;90:239-58.  Back to cited text no. 6
    
7.Renfroe E. Study of facial pattern associated with class I, class II div I and class II div II malocclusions. Angle Orthod 1948;18:12-5.  Back to cited text no. 7
    
8.Bjork A. Some biological aspects of prognathism and occlusion of the teeth. Acta Odontol Scand 1950;9:1-40.  Back to cited text no. 8
[PUBMED]    
9.Coben SE. The integration of facial skeletal variants. Am J Orthod 1955;41:407-34.  Back to cited text no. 9
    
10.Moss ML. Correlation of cranial base angulation with cephalic malformations and growth disharmonies of dental interest. NY State Dent J 1955;24:452-4.  Back to cited text no. 10
    
11.Hopkin GD. The growth factor in the prognosis of treated case of angle class III malocclusion. Trans Eur Orthod Soc 1965;41:353-65.  Back to cited text no. 11
    
12.Bhatia SN, Leighton BC. A Manual of Facial Growth. Oxford: Oxford University Press; 1993.  Back to cited text no. 12
    
13.Hopkin GB, Houston WJ, James GA. The cranial base as an aetiological factor in malocclusion. Angle Orthod 1968;38:250-5.  Back to cited text no. 13
[PUBMED]    
14.Varjanne I, Koski K. Cranial base, sagittal jaw relationship and occlusion. A radiological-craniometric appraisal. Proc Finn Dent Soc 1982;78:179-83.  Back to cited text no. 14
[PUBMED]    
15.Järvinen S. Saddle angle and maxillary prognathism: A radiological analysis of the association between the NSAr and SNA angles. Br J Orthod 1984;11:209-13.  Back to cited text no. 15
    
16.Kasai K, Moro T, Kanazawa E, Iwasawa T. Relationship between cranial base and maxillofacial morphology. Eur J Orthod 1995;17:403-10.  Back to cited text no. 16
    
17.Moyers RE. Hand Book of Orthodontics. IV th ed. London: Mosby Publishers; 1988.  Back to cited text no. 17
    
18.Enlow DH. Facial Growth. 3 rd ed. Philedelphia: W.B Saunders; 1990.  Back to cited text no. 18
    
19.Profitt W, Fields HW. Contemporary Orthodontics. 2 nd ed. St Louis: Mosby Year Book; 1993.  Back to cited text no. 19
    
20.Bjork A. Cranial base development. Am J Orthod 1955;41:198-225.  Back to cited text no. 20
    
21.Baccetti T, Antonini A, Franchi L, Tonti M, Tollaro I. Glenoid fossa position in different facial types: A cephalometric study. Br J Orthod 1997;24:55-9.  Back to cited text no. 21
    
22.Kerr WJ, Hirst D. Craniofacial characteristics of subjects with normal and postnormal occlusions - A longitudinal study. Am J Orthod Dentofacial Orthop 1987;92:207-12.  Back to cited text no. 22
[PUBMED]    
23.Anderson D, Popovich F. Relation of cranial base flexure to cranial form and mandibular position. Am J Phys Anthropol 1983;61:181-7.  Back to cited text no. 23
[PUBMED]    
24.Kerr WJ, Adams CP. Cranial base and jaw relationship. Am J Phys Anthropol 1988;77:213-20.  Back to cited text no. 24
    
25.Harris JE, Kowalski CJ, Walker SJ. Dentofacial differences between "normal" sibs of Class II and Class III patients. Angle Orthod 1975;45:103-7.  Back to cited text no. 25
[PUBMED]    
26.Bacon W, Eiller V, Hildwein M, Dubois G. The cranial base in subjects with dental and skeletal Class II. Eur J Orthod 1992;14:224-8.  Back to cited text no. 26
    
27.Varrela J. Early developmental traits in class II malocclusion. Acta Odontol Scand 1998;56:375-7.  Back to cited text no. 27
[PUBMED]    
28.Kerr WJ, Miller S, Ayme B, Wilhelm N. Mandibular form and position in 10-year-old boys. Am J Orthod Dentofacial Orthop 1994;106:115-20.  Back to cited text no. 28
    
29.Klocke A, Nanda RS, Kahl-Nieke B. Role of cranial base flexure in developing sagittal jaw discrepancies. Am J Orthod Dentofacial Orthop 2002;122:386-91.  Back to cited text no. 29
    
30.Weidenreich F. Some particulars of skull and brain of early hominids and their bearing on the problem of the relationship between man and anthropoids. Am J Phys Anthropol 1947;5:387-427.  Back to cited text no. 30
[PUBMED]    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]


This article has been cited by
1 Cone-Beam Computed Tomography of Osteogenesis Imperfecta Types III and IV: Three-Dimensional Evaluation of Craniofacial Features and Upper Airways
Natalie Reznikov,Didem Dagdeviren,Faleh Tamimi,Francis Glorieux,Frank Rauch,Jean-Marc Retrouvey
JBMR Plus. 2019;
[Pubmed] | [DOI]
2 CBCT analysis of pharyngeal airway volume and comparison of airway volume among patients with skeletal Class I, Class II, and Class III malocclusion: A retrospective study
Mandovi Nath,Junaid Ahmed,Ravikiran Ongole,Ceena Denny,Nandita Shenoy
CRANIO®. 2019; : 1
[Pubmed] | [DOI]
3 Farkli Maloklüzyonlar ile Kafa Tabani Açilanmalari Arasindaki Iliskinin Üç Boyutlu Degerlendirilmesi
Ilhan Metin Dagsuyu
SDÜ Tip Fakültesi Dergisi. 2018;
[Pubmed] | [DOI]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Materials and Me...
Results
Discussion
Conclusion
References
Article Tables

 Article Access Statistics
    Viewed3104    
    Printed80    
    Emailed0    
    PDF Downloaded507    
    Comments [Add]    
    Cited by others 3    

Recommend this journal