Analysis of soft tissue facial profile in white males Christian G. Zylinski, DDS," Ram S. Nanda, DDS, MS, PhD, b and Sunil Kapila, BDS, MS = Oklahonta City, Okla. Three of the integumental variables, namely, the total facial convexity, upper lip to esthetic plane, and lower lip length, showed significant measurement errors in the preadolescent boys. Large standard deviations were also found for several variables in both age groups. This suggests that a range of values, rather than means, should be used in clinical cephalometric evaluations. A table of means, standard deviations, and ranges for the variables evaluated is provided. The nasolabial and the mentolabial angles did not differ significantly between the younger and the older age groups. The total soft tissue facial convexity was noted to have a marginally significant difference between the adults and children. Other variables were significantly different between the two age groups, and indicated that the adults had a relatively straighter facial profile than the children. In addition, the upper and lower lips were more retrusive relative to the esthetic plane in adults. Sagittal proportions relating nasal depth/nose to most protrusive lip/chin to most protrusive lip were found to have a ratio of 2.1:1.0:1.2 in children and 1.8:1.0:0.3 in adults. (AMJ ORTHOD DENTOFACORTHOP 1992;101:514-8.)
F a c i a l harmony and balance are determined by the facial skeleton and its soft tissue drape. The architecture and topographic relationships of the facial skeleton form a "foundation" on which the esthetics o f the face are based. However, it is the structure of the overlying soft tissues and their relative proportions that provide the visual impact of the face. Soft tissue changes because of growth, as well as mechanotherapy, further add to its importance in orthodontic evaluations. Several investigators t7 have noted the importance of the soft tissue integument in the determination of facial esthetics, as well as its growth changes, that behave independently from those of the underlying skeleton. Burstone t noted the existence of sexual dimorphism in the growth trends of the soft tissue areas inferior to the nose, with an overall greater thickness of these tissues in the male subjects. Subtelny 2 demonstrated, in a longitudinal study on 30 subjects, who were equally divided by sex and who were 3 months to 18 years old, that, although the skeletal profile tended to straighten with maturation, the soft tissue profile remained relatively convex. This was attributed to the greater increase in soft tissue thickness over the maxilla than over either the mandible or the forehead. He concluded that soft tissue contours diverge from those of the underlying skeletal structures in certain areas,
=Clinical Assistant Professor, Department of Orthodontics, University of Oklahoma College of Dentistry. ~Professor and Chairman, Department of Orthodontics, University of Oklahoma" College of Dentistry. 'Former Resident and Clinical Instructor, Department of Orthodontics, University of Oklahoma College of Dentistry; presently Adjunct Assistant Professor and doctoral student at University of California, San Francisco. 811128455
514
whereas other areas, such as the lips, show a strong tendency to follow the hard tissue changes. The increase in the soft tissue convexity is consistent with earlier findings of Pelton and Elsasser, s but contrasts with later findings of Mauchamp and Sassouni. 4 Although providing an essential insight into growth changes in soft tissue profile, longitudinal studies have one major limitation, namely, the ability to preselect esthetically pleasing and harmonious faces for investigation. These studies therefore do not provide normative data with which a clinician can adequately compare his patients. The purpose of the present study was to supplement data on normative values of some clinically important soft tissue dimensions for white male patients. The specific objectives of this investigation were to define, for white preadolescent boys and men with esthetically pleasing faces, (1) norms for several integumental variables and to statistically evaluate differences in the mean values of these measurements between the two age groups, and (2) a method for evaluating sagittal proportions of the nose, lips, and chin and to determine norms for these proportions. MATERIALS AND METHODS
Sixty white male subjects, satisfying the criteria of pleasing face, balanced facial profile, competent lips, and normal overjet and overbite relationship, were selected independently by two orthodontists and one lay person by means of standardized frontal and lateral extraoral photographs. Subjects who satisfied this criteria even when they had malocclusions were not excluded from the study. The sample comprised of lateral head cephSlograms of 31 boys aged 5 to 10 years old (mean age = 7.6 ),ears) and 29 men aged 22 to 32 years old (mean age = 26.2 years). All cephalograms were taken with the lips in light contact and teeth in occlusion.
Volume 101 Number 6
Soft tissue profile hi white males 515
O:j
B
Franldorl _ ~
~
J c
D
F~ Horlzonlll .
I~r~
F
Fig. 1. Skeletal and soft tissue landmarks, planes and measurements used in this study. The hard tissue landmarks are nasion (N), porion (P), orbitale (Or), subspinale (A), pogonion (Pg), and menton (Me). Integumental landmarks include soft tissue nasion (N'), pronasale (Pr), subnasale (Sn), labrale superius (Ls), stomion (St), labrale inferius (L0, soft tissue supramentale (B'), and soft tissue pogonion (Pg'). Description of the measurements made are as follows: A, 1, Angle of skeletal convexity (N-APg), 2, angle of soft tissue facial convexity exluding the nose (N'-Sn-Pg'), and 3, angle of total facial convexity (N'-Pr-Pg'). B, 4, Soft tissue facial plane angle (N'-Pg' to FH plane), 5, nasolabia! angle (tangent to collumella of nose-Sn-Ls), 6, mentolabial angle (Li-B'-tangent to chin), and 7, Z angle (Pg'most protrusive lip to FH plane). C, 8, Upper lip (Ls) to esthetic (F:) plane, 9, lower lip (Li) to esthetic (E) plane, 10, upper lip length (Sn-St), and 11, lower lip length (St-Me'). D, 12, Nasal depth (Pr-N'), 13, sagittal nasal tip to lip distance (Pr-most protrusive lip), and 14, sagittal chin to lip distance (Pg'most protrusive lip).
The radiographs were traced, and several hard and soft tissue landmarks were defined (Fig. I). The skeletal landmarks were determined as described by Thurow. tl All soft tissue landmarks, except soft tissue menton, were determined according to the definitions of Chacanos and Bartroff. 5 Soft tissue menton was a point constructed where a line perpendicular to the Frankfort horizontal plane, passing through menton, intersects the integumental outline. The angular measurements made are depicted in Figs. 1, A and B and included: 1. Angles of skeletal convexity (N-A-Pg). 2. Angle of soft tissue facial convexity excluding the nose (N'-Sn-Pg'). 3. Angle of total facial convexity (N'-Pr-Pg'). 4. Soft tissue facial plane angle (N'-Pg' to Frankfort horizontal plane). 5. Nasolabial angle (tangent to columella of nose-SnLs).
6. Mentolabial angle (Li-B'-tangent to chin). 7. Z angle (Pg'-most protrusive lip to Frankfort horizontal plane). All sagittal and vertical linear dimensions were measured parallel and perpendicular to the FIt plane respectively. Esthetic plane measurements were made on a perpendicular to the E plane (Figs. 1, C and D). The linear variables determined were: 8. Upper lip distance to esthetic plane (Ls-E). 9. Lower lip distance to esthetic plane (Li-E). 10. Upper lip length (Sn-St). 11. Lower lip length (St-Me'). 12. Nasal depth (Pr-N'). 13. Sagittal nasal tip to lip distance (Pr to most protrusive lip). 14. Sagittal chin to lip distance (Pg' to most protrusive lip). A positive sign was ascribed to this variable when the lip lay anterior to the chin; a negative value
516
Zylinski, Nanda, and Kapila
Am.
J. Orthod.Dent~ac. Orthop. June 1992
Table I. M e a n s , standard deviations, and ranges for 1 skeletal and 13 soft tissue variables in white preadolescent boys and m e n with well-balanced and esthetically pleasing faces
Preadolescent boys (N = 31) Variable
Means
Angle of skeletal convexity Soft tissue facial convexity excluding the
+6.5
l (SD) I
Men (N = 29) l (SD) l
Min
I
p
,fin
Ma.~
Means
(4.4)
- 1.7
+ 15.5
+2. I
(4.6)
-4.6
+ 15.0
0.0004
+ 16.7
(3.9)
+ 9.1
+ 25.8
+ 14.0
(4.9)
+ 4. !
+ 26.6
0.026
47.5
(2.7)
41.9
53.0
49.6
(5.4)
38.5
63.9
NS
89.5
(3.2)
83.8
97.5
94.2
(2.4)
88.8
100.0
0.0001
I I 1.5 127.2 71.1 -0.1
(7.8) (15.9) (4.4) (1.3)
93.5 91.8 61.9 -2.6
125.0 157.2 79.6 + 1.9
110.8 124.3 82.7 -7.1
(7.6) (13.1) (6.1) (2.9)
96.7 95.9 70.0 - 11.5
125.6 151.3 96.0 +0.6
NS NS 0.0001 0.0001
-0.0
(1.7)
-3.3
-i-3.0
-5.2
(3.0)
-9.1
+0.3
0.0001
20.7
(1.4)
17~8
23;7
23.7
(2.3)
19.7
30.5
0.0001
43.5
(3.4)
37.3
52.4
57.5
(3.0)
52.0
63.2
0.0001
17.8
(2.5)
12.8
23.0
28.8
(3.1)
22.3
35.5
0.0001
8.4
(2.2)
1.5
13.4
15.6
(3.5)
4.4
20.4
0.0001
10.0
(2.5)
3.5
14.2
4.9
(4.1)
-4.0
23.5
0.0001
M~
nose
Angle of total facial convexity Soft tissue facial plane angle Nasolabial angle Mentolabial angle Z angle Upper lip to isthetic plane (mm) Lower lip to isthetic plane (mm) Upper lip length (mm) Lower lip length (mm) Nasal depth (mm) Sagittal nasal tip to lip distance (mm) Sagittal chin to lip distance (mm)
p is the probability values showing the significance of differences between the two age groups.
was ascribed when the lip was placed posterior to the chin. The tracing and measurement error was determined by retracing 10 randomly selected cephalograms for each age group. The initial and repeat measurements were compared with the paired t test to determine the significance of any errors. Those dimensions found to have a significantly high error were remeasured for the entire sample, and an average of the first and second readings was used for this investigation. A comparison of the mean values obtained for all variables for adults and children was made with a two group t test. RESULTS T h e analysis for error of method revealed three dim e n s i o n s with a statistically significant error that occurred only in preadolescent boys. These were the total soft tissue facial convexity (p < 0.01), u p p e r ' l i p t0" esthetic plane (p < 0.01), and lower lip length (p < 0.01). All other variables showed an insignificant error at the 5% level o f confidence. The means, standard deviations, and ranges for the
14 variables for both age groups are reported in Table I. T h e significance (p values) of any differences in the m e a n s of these variables between preadolescent boys and m e n are also indicated. Means o f all variables, except total soft tissue facial convexity, nasolabial angle and mentolabial angle, were significantly different between the two age groups. DISCUSSION Previous investigations ~3ts on the reliability of integumental l a n d m a r k location and m e a s u r e m e n t s indicate that soft tissue d i m e n s i o n s display the same degree of error as c o r r e s p o n d i n g hard tissue variables. Wisth and Boe, t4 however, pointed out that lip structure influences the reproducibility of reference points in children with i n c o m p e t e n t lips, but children and adults with competent lips did not show significant m e a s u r e m e n t errors. A l t h o u g h the present investigation was restricted to subjects who had balanced facial profiles and c o m petent lips, it revealed three variables with significant
rob,me tOI
Soft tissue profile in white males
Number6
517
Table II. Comparison of means of several soft tissue profile measurements in white males of this study with those found by other investigators* (Ages at which the comparisons are made are indicated at the foot of the table.)
Variable Angle of skeletal convexity Soft tissue convexity excluding the nose Angle of total facial convexity Soft tissue facial plane angle Nasolabial angle Mentolabial angle Z angle Upper lip tO esthetic plane (mm) Lower lip to esthetic plane (mm)
*1. 2. 3. 4.
Data Data Data Data
from from from from
I
Age group
Present study
Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult
+ 6.5 + 2. I + ! 6.7 + 14.0 47.5 49.6 89.5 94.2 111.5 I 10.8 127.2 124.3 71.1 82.7 - 0.1 -7.1 • 0.0 -5.2
Subteln)~ +6.4 + 1.0 + 18.7 + 16.5 41.6 47.0
I
Bishara et al. ~
Other studies
+ 11.2 +7.0 34.5 39.8 88.1 ~6
68.3 75.5 -0.64 -5.18 - 0.22 -3.98
108.77 105.87 125.97 125.17 78 * 80 ~ -0.46 ~ -4.257 + 0.057 -2.757
Subtelny2 and Kapila' are for preadolescent boys at 8 )'ears and men at 18 33'ears. Bishara6 et al. are for preadolescent boys at 8 ],'ears and men of unspecified age. Merrifield* are for a pooled sample of both sexes of adolescents 11 to 15 ],'ears of age and for adults of unspecified age. Neger t6 are for a tx:~oled sample of both sexes with an age range of 9 to 16 years.
measurement errors. These errors were noted only in the preadolescent boys and included the total soft tissue facial convexity (N'-Pr-Pg'), upper lip to esthetic plane (Ls-E), and lower lip length (St-Me'). This was possibly due to lack of full definition of facial contours in preadolescent boys and the inherent error in locating the landmarks. Several variables were found to have large standard deviations relative to their means (Table 1). These included the skeletal convexity, soft tissue convexity excluding the nose, mentolabial angle, upper and lower lips to esthetic plane, nasal depth, as well as sagittal nose to lip, and chin-to-lip distances in both age groups. The large standard deviations indicate that these measurements display a great degree of individual variability. This implies that when clinical cephalometric evaluations are completed for these variables, comparisons should be made with a normal range of values rather than with just the mean. A comparison of the means for all variables between the two age groups indicated that the face of a man is significantly different from that of a child (Table I). All variables, except the nasolabial and mentolabial angles, showed a statistically significant difference between the two samples. A third variable, the total soft tissue facial convexity, was found to have a marginally significant difference at p < 0.056. Angles of convexity of the facial skeleton and soft
tissue excluding the nose tended to be smaller in the adults, indicating a relatively straighter facial profile in adults. The soft tissue facial plane angle and the Z angle were greater in the adults than the children possibly due to a larger chin resulting in a less convex facial profile in the adult sample. The upper and lower lips receded relative to the E line from the younger to the older age groups. This could be attributed to the greater sagittal depth of the nose and chin than the lips in the adult sample. Further proof of the differential changes in the relationship of the nose, lips, and chin in the sagittal direction is provided when the nasal depth, nose-to-lip and chin-to-lip measurements are compared for the two samples. These anteroposterior dimensions, measured parallel to the Frankfort horizontal plane, indicate that nasal depth increases relative to the soft tissue nasion and the most protrusive lip from the preadolescent to the adult group. The tneans for these two variables were greater in the men over the preadolescent boys by 11 mm and 7.2 mm, respectively. In addition, the chin was placed an average of 5.1 mm further anteriorly relative to the most protrusive lip in the adult sample as compared with the preadolescent sample. The vertical heights of the upper and lower lips were also significantly greater in the adults. The means for upper and lower lip lengths were larger in the adults than in the preadolescents by 3.0 mm and 14.0 mm, respectively.
51 8
_=..
..;Z,.linski, N a n d a , a n d .._,.__Kaoila
The findings of this study were compared with those of Subtelny, 2 Bishara et al.,6 as well as selected relevant measurements from other authors. 7'9't6 These comparisons are summarized in Table II. The three angles of convexity assessed in previous investigations were the internal angles formed between two lines intersecting at pronasale, subnasale, or A point. For comparison with findings of the present study these angles were converted into the superior angle by subtracting the means obtained by the previous investigators from 180 ~ The means found by Subtelny'- for skeletal convexity and soft tissue convexity excluding the nose in both age groups, as well as the total soft tissue convexity in adults, were similar to those determined in the present investigation. On the other hand, values defined by Bishara et al. 6 for the total soft tissue convexity, soft tissue convexity excluding the nose and Z angle, diffei'cd from those found in this study. Variation in Z angle values found by Merrifield 9 in adolescents ages 11 to 15 years old and the findings in preadolescent boys o f the present investigation can be attributed tO the fact that his subjects had been treated t o specific dentoalveolar standards and also to the age differences o f the two samples. Similarly, growth of ihe nose-and chin could explain the differences in estheiic plane values in the adult male subjects o f the present study at a mean age of 26.2 years as compared with those at age 18 years observed by Kapila 7 and Nanda et al. 19 Some o f the variations between the present investigation and the other studies may have arisen because o f differences in the selection and ages of samples evaluated and the landmarks used. The combined male and female data provided by Merrifield9 and Neger 16 may have attributed to further variations between their findings and those o f this investigation. Although the present study did not include a female sample, it is reasonable to expect sex differences in soft tissue facial contours, rendering the normative values on the basis o f pooled samples unreliable.
Sagittal facial p r o p o r t i o n s Ratios or proportions are an effective method for defining balanced facial dimensions as they compensate for extremes in sizes and do not rely on absolute millimetric measurements for establishing norm values. Several vertical and transverse proportions have been proposed previously m'lT'ts and have become an accepted method for evaluation o f facial balance. In this study three sagittal variables were determined for the specific purpose of defining proportions of an esthetic and harmonious face in the anteroposterior plane. The nasal depth, nose to most protrusive lip, and chin to most protrusive lip ratios were found to be 2 . 1 : 1 . 0 : 1 . 2 in preadolescent boys and 1 . 8 : 1 . 0 : 0 . 3 in men (Fig. 1, D). The difference in the two ratios also indicates
Am. J. Orthod. Dentofac. Orthop. June 1992
the variation in soft tissue profiles between children and adults. SUMMARY
Lateral head cephalograms of 31 preadolescent boys and 29 men, who had well-balanced and esthetic facial profiles, were evaluated to define norms for several integumental variables. In addition, analysis to determine age differences in these variables was performed with a two group t test. A method for evaluating sagittal proportions o f the nose, lips, and chin was also proposed. REFERENCES I. BurstoneCJ. lntegumentalcontourandextensionpatterns. Angle Orthod 1959;29:93-104. 2. Subtelny JD. A longitudinal study of soft tissue facial structures and their profile characteristics defined in relation to underlying skeletal structure. AM J OR'moP 1959;45:481-507. 3. Subtelny JD. The soft tissue profile, growth and treatment changes. Angle Orthod 1961;31:105-22. 4. Mauchamp O, Sassouni V. Growth and prediction of skeletal and soft tissue profiles. AM J ORTIIOD1973;64:83-94. 5. Chaconas SJ, Bartroff JD. Prediction of normal soft tissue facial changes. Angle Orthod 1975;45:12-25. 6. Bishara SE, ttession TJ, Peterson LC. Longitudinal soft tissue profile changes. AM J OR'atoP 1985;88:209-23. 7. Kapila S. Lip profile growth changes: a longitudinal cephalometric study from 7 to 18 years. [Thesis] Oklahoma City: University of Oklahoma, 1986. 8. pelion WJ, Elsasser WA. Studies of dentofacial morphol~y IV. Profile changes among 6,829 white individuals according to age and sex. Angle Orthod 1955;25:199-207. 9. Merfifield LL. Tile profile line as an aid in critically evaluating facial esthetics. A.',IJ OR'troD 1966;52:804-22. 10. Ricketts RM. Esthetics, environment, and the law of lip relation. A.',t J ORvlIOD1968;54:272-89. 11. Thurow RC. Atlas of orthodontic principles. St. Louis: CV Mosby, 1970:30-89. 12. Downs WB. Variations in facial relationships: their significance in treatment and prognosis. AM J ORTIIOD1948;34:811-40. 13. Wisth PJ. Changes of the soft tissue profile during growth. Trans Europ Orthod Soc 1972:123-31. 14. Wisth PJ, Boe OE. The reliability of cephalometrie soft tissue measurements. Archs. Oral Biol 1975;20:595-99. 15. ttillesund E, Fjeld D, Zachrisson BU. Reliability of soft tissue profile in cephalometrics. AM J O~THOD1978;74:537-50. 16. Neger M. A quantitative method for the evaluation of soft tissue profile. AM J OR'I-ItOD1959;45:738-51. 17. Legan ilL, Burstone CJ. Soft tissue cephalometric analysis for ortho,gnathic surgery. J Oral Surgery 1980;38:744-51. 18. Ricketts RM. The divine proportion. A new movement in orthodontics. In: Balbach DR, ed. Proceedings of the foundation for orthodontic research, 1980-81. Ann Arbor: ELS Lithographics, 1982:29-43. 19. Nanda RS, Meng HP, Kapila S, Goorhuis Y. Growth changes in the soft tissue facial profile. Angle Orthod 1990;60:177-90. Reprint requests to:
Dr. Ram S. Nanda College of Dentistry" The University of Oklahoma P.O. Box 26901 1001 Shanton L. Young Blvd. Oklahoma City, OK 73190
F a c i a l harmony and balance are determined by the facial skeleton and its soft tissue drape. The architecture and topographic relationships of the facial skeleton form a "foundation" on which the esthetics o f the face are based. However, it is the structure of the overlying soft tissues and their relative proportions that provide the visual impact of the face. Soft tissue changes because of growth, as well as mechanotherapy, further add to its importance in orthodontic evaluations. Several investigators t7 have noted the importance of the soft tissue integument in the determination of facial esthetics, as well as its growth changes, that behave independently from those of the underlying skeleton. Burstone t noted the existence of sexual dimorphism in the growth trends of the soft tissue areas inferior to the nose, with an overall greater thickness of these tissues in the male subjects. Subtelny 2 demonstrated, in a longitudinal study on 30 subjects, who were equally divided by sex and who were 3 months to 18 years old, that, although the skeletal profile tended to straighten with maturation, the soft tissue profile remained relatively convex. This was attributed to the greater increase in soft tissue thickness over the maxilla than over either the mandible or the forehead. He concluded that soft tissue contours diverge from those of the underlying skeletal structures in certain areas,
=Clinical Assistant Professor, Department of Orthodontics, University of Oklahoma College of Dentistry. ~Professor and Chairman, Department of Orthodontics, University of Oklahoma" College of Dentistry. 'Former Resident and Clinical Instructor, Department of Orthodontics, University of Oklahoma College of Dentistry; presently Adjunct Assistant Professor and doctoral student at University of California, San Francisco. 811128455
514
whereas other areas, such as the lips, show a strong tendency to follow the hard tissue changes. The increase in the soft tissue convexity is consistent with earlier findings of Pelton and Elsasser, s but contrasts with later findings of Mauchamp and Sassouni. 4 Although providing an essential insight into growth changes in soft tissue profile, longitudinal studies have one major limitation, namely, the ability to preselect esthetically pleasing and harmonious faces for investigation. These studies therefore do not provide normative data with which a clinician can adequately compare his patients. The purpose of the present study was to supplement data on normative values of some clinically important soft tissue dimensions for white male patients. The specific objectives of this investigation were to define, for white preadolescent boys and men with esthetically pleasing faces, (1) norms for several integumental variables and to statistically evaluate differences in the mean values of these measurements between the two age groups, and (2) a method for evaluating sagittal proportions of the nose, lips, and chin and to determine norms for these proportions. MATERIALS AND METHODS
Sixty white male subjects, satisfying the criteria of pleasing face, balanced facial profile, competent lips, and normal overjet and overbite relationship, were selected independently by two orthodontists and one lay person by means of standardized frontal and lateral extraoral photographs. Subjects who satisfied this criteria even when they had malocclusions were not excluded from the study. The sample comprised of lateral head cephSlograms of 31 boys aged 5 to 10 years old (mean age = 7.6 ),ears) and 29 men aged 22 to 32 years old (mean age = 26.2 years). All cephalograms were taken with the lips in light contact and teeth in occlusion.
Volume 101 Number 6
Soft tissue profile hi white males 515
O:j
B
Franldorl _ ~
~
J c
D
F~ Horlzonlll .
I~r~
F
Fig. 1. Skeletal and soft tissue landmarks, planes and measurements used in this study. The hard tissue landmarks are nasion (N), porion (P), orbitale (Or), subspinale (A), pogonion (Pg), and menton (Me). Integumental landmarks include soft tissue nasion (N'), pronasale (Pr), subnasale (Sn), labrale superius (Ls), stomion (St), labrale inferius (L0, soft tissue supramentale (B'), and soft tissue pogonion (Pg'). Description of the measurements made are as follows: A, 1, Angle of skeletal convexity (N-APg), 2, angle of soft tissue facial convexity exluding the nose (N'-Sn-Pg'), and 3, angle of total facial convexity (N'-Pr-Pg'). B, 4, Soft tissue facial plane angle (N'-Pg' to FH plane), 5, nasolabia! angle (tangent to collumella of nose-Sn-Ls), 6, mentolabial angle (Li-B'-tangent to chin), and 7, Z angle (Pg'most protrusive lip to FH plane). C, 8, Upper lip (Ls) to esthetic (F:) plane, 9, lower lip (Li) to esthetic (E) plane, 10, upper lip length (Sn-St), and 11, lower lip length (St-Me'). D, 12, Nasal depth (Pr-N'), 13, sagittal nasal tip to lip distance (Pr-most protrusive lip), and 14, sagittal chin to lip distance (Pg'most protrusive lip).
The radiographs were traced, and several hard and soft tissue landmarks were defined (Fig. I). The skeletal landmarks were determined as described by Thurow. tl All soft tissue landmarks, except soft tissue menton, were determined according to the definitions of Chacanos and Bartroff. 5 Soft tissue menton was a point constructed where a line perpendicular to the Frankfort horizontal plane, passing through menton, intersects the integumental outline. The angular measurements made are depicted in Figs. 1, A and B and included: 1. Angles of skeletal convexity (N-A-Pg). 2. Angle of soft tissue facial convexity excluding the nose (N'-Sn-Pg'). 3. Angle of total facial convexity (N'-Pr-Pg'). 4. Soft tissue facial plane angle (N'-Pg' to Frankfort horizontal plane). 5. Nasolabial angle (tangent to columella of nose-SnLs).
6. Mentolabial angle (Li-B'-tangent to chin). 7. Z angle (Pg'-most protrusive lip to Frankfort horizontal plane). All sagittal and vertical linear dimensions were measured parallel and perpendicular to the FIt plane respectively. Esthetic plane measurements were made on a perpendicular to the E plane (Figs. 1, C and D). The linear variables determined were: 8. Upper lip distance to esthetic plane (Ls-E). 9. Lower lip distance to esthetic plane (Li-E). 10. Upper lip length (Sn-St). 11. Lower lip length (St-Me'). 12. Nasal depth (Pr-N'). 13. Sagittal nasal tip to lip distance (Pr to most protrusive lip). 14. Sagittal chin to lip distance (Pg' to most protrusive lip). A positive sign was ascribed to this variable when the lip lay anterior to the chin; a negative value
516
Zylinski, Nanda, and Kapila
Am.
J. Orthod.Dent~ac. Orthop. June 1992
Table I. M e a n s , standard deviations, and ranges for 1 skeletal and 13 soft tissue variables in white preadolescent boys and m e n with well-balanced and esthetically pleasing faces
Preadolescent boys (N = 31) Variable
Means
Angle of skeletal convexity Soft tissue facial convexity excluding the
+6.5
l (SD) I
Men (N = 29) l (SD) l
Min
I
p
,fin
Ma.~
Means
(4.4)
- 1.7
+ 15.5
+2. I
(4.6)
-4.6
+ 15.0
0.0004
+ 16.7
(3.9)
+ 9.1
+ 25.8
+ 14.0
(4.9)
+ 4. !
+ 26.6
0.026
47.5
(2.7)
41.9
53.0
49.6
(5.4)
38.5
63.9
NS
89.5
(3.2)
83.8
97.5
94.2
(2.4)
88.8
100.0
0.0001
I I 1.5 127.2 71.1 -0.1
(7.8) (15.9) (4.4) (1.3)
93.5 91.8 61.9 -2.6
125.0 157.2 79.6 + 1.9
110.8 124.3 82.7 -7.1
(7.6) (13.1) (6.1) (2.9)
96.7 95.9 70.0 - 11.5
125.6 151.3 96.0 +0.6
NS NS 0.0001 0.0001
-0.0
(1.7)
-3.3
-i-3.0
-5.2
(3.0)
-9.1
+0.3
0.0001
20.7
(1.4)
17~8
23;7
23.7
(2.3)
19.7
30.5
0.0001
43.5
(3.4)
37.3
52.4
57.5
(3.0)
52.0
63.2
0.0001
17.8
(2.5)
12.8
23.0
28.8
(3.1)
22.3
35.5
0.0001
8.4
(2.2)
1.5
13.4
15.6
(3.5)
4.4
20.4
0.0001
10.0
(2.5)
3.5
14.2
4.9
(4.1)
-4.0
23.5
0.0001
M~
nose
Angle of total facial convexity Soft tissue facial plane angle Nasolabial angle Mentolabial angle Z angle Upper lip to isthetic plane (mm) Lower lip to isthetic plane (mm) Upper lip length (mm) Lower lip length (mm) Nasal depth (mm) Sagittal nasal tip to lip distance (mm) Sagittal chin to lip distance (mm)
p is the probability values showing the significance of differences between the two age groups.
was ascribed when the lip was placed posterior to the chin. The tracing and measurement error was determined by retracing 10 randomly selected cephalograms for each age group. The initial and repeat measurements were compared with the paired t test to determine the significance of any errors. Those dimensions found to have a significantly high error were remeasured for the entire sample, and an average of the first and second readings was used for this investigation. A comparison of the mean values obtained for all variables for adults and children was made with a two group t test. RESULTS T h e analysis for error of method revealed three dim e n s i o n s with a statistically significant error that occurred only in preadolescent boys. These were the total soft tissue facial convexity (p < 0.01), u p p e r ' l i p t0" esthetic plane (p < 0.01), and lower lip length (p < 0.01). All other variables showed an insignificant error at the 5% level o f confidence. The means, standard deviations, and ranges for the
14 variables for both age groups are reported in Table I. T h e significance (p values) of any differences in the m e a n s of these variables between preadolescent boys and m e n are also indicated. Means o f all variables, except total soft tissue facial convexity, nasolabial angle and mentolabial angle, were significantly different between the two age groups. DISCUSSION Previous investigations ~3ts on the reliability of integumental l a n d m a r k location and m e a s u r e m e n t s indicate that soft tissue d i m e n s i o n s display the same degree of error as c o r r e s p o n d i n g hard tissue variables. Wisth and Boe, t4 however, pointed out that lip structure influences the reproducibility of reference points in children with i n c o m p e t e n t lips, but children and adults with competent lips did not show significant m e a s u r e m e n t errors. A l t h o u g h the present investigation was restricted to subjects who had balanced facial profiles and c o m petent lips, it revealed three variables with significant
rob,me tOI
Soft tissue profile in white males
Number6
517
Table II. Comparison of means of several soft tissue profile measurements in white males of this study with those found by other investigators* (Ages at which the comparisons are made are indicated at the foot of the table.)
Variable Angle of skeletal convexity Soft tissue convexity excluding the nose Angle of total facial convexity Soft tissue facial plane angle Nasolabial angle Mentolabial angle Z angle Upper lip tO esthetic plane (mm) Lower lip to esthetic plane (mm)
*1. 2. 3. 4.
Data Data Data Data
from from from from
I
Age group
Present study
Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult Preadolescent Adult
+ 6.5 + 2. I + ! 6.7 + 14.0 47.5 49.6 89.5 94.2 111.5 I 10.8 127.2 124.3 71.1 82.7 - 0.1 -7.1 • 0.0 -5.2
Subteln)~ +6.4 + 1.0 + 18.7 + 16.5 41.6 47.0
I
Bishara et al. ~
Other studies
+ 11.2 +7.0 34.5 39.8 88.1 ~6
68.3 75.5 -0.64 -5.18 - 0.22 -3.98
108.77 105.87 125.97 125.17 78 * 80 ~ -0.46 ~ -4.257 + 0.057 -2.757
Subtelny2 and Kapila' are for preadolescent boys at 8 )'ears and men at 18 33'ears. Bishara6 et al. are for preadolescent boys at 8 ],'ears and men of unspecified age. Merrifield* are for a pooled sample of both sexes of adolescents 11 to 15 ],'ears of age and for adults of unspecified age. Neger t6 are for a tx:~oled sample of both sexes with an age range of 9 to 16 years.
measurement errors. These errors were noted only in the preadolescent boys and included the total soft tissue facial convexity (N'-Pr-Pg'), upper lip to esthetic plane (Ls-E), and lower lip length (St-Me'). This was possibly due to lack of full definition of facial contours in preadolescent boys and the inherent error in locating the landmarks. Several variables were found to have large standard deviations relative to their means (Table 1). These included the skeletal convexity, soft tissue convexity excluding the nose, mentolabial angle, upper and lower lips to esthetic plane, nasal depth, as well as sagittal nose to lip, and chin-to-lip distances in both age groups. The large standard deviations indicate that these measurements display a great degree of individual variability. This implies that when clinical cephalometric evaluations are completed for these variables, comparisons should be made with a normal range of values rather than with just the mean. A comparison of the means for all variables between the two age groups indicated that the face of a man is significantly different from that of a child (Table I). All variables, except the nasolabial and mentolabial angles, showed a statistically significant difference between the two samples. A third variable, the total soft tissue facial convexity, was found to have a marginally significant difference at p < 0.056. Angles of convexity of the facial skeleton and soft
tissue excluding the nose tended to be smaller in the adults, indicating a relatively straighter facial profile in adults. The soft tissue facial plane angle and the Z angle were greater in the adults than the children possibly due to a larger chin resulting in a less convex facial profile in the adult sample. The upper and lower lips receded relative to the E line from the younger to the older age groups. This could be attributed to the greater sagittal depth of the nose and chin than the lips in the adult sample. Further proof of the differential changes in the relationship of the nose, lips, and chin in the sagittal direction is provided when the nasal depth, nose-to-lip and chin-to-lip measurements are compared for the two samples. These anteroposterior dimensions, measured parallel to the Frankfort horizontal plane, indicate that nasal depth increases relative to the soft tissue nasion and the most protrusive lip from the preadolescent to the adult group. The tneans for these two variables were greater in the men over the preadolescent boys by 11 mm and 7.2 mm, respectively. In addition, the chin was placed an average of 5.1 mm further anteriorly relative to the most protrusive lip in the adult sample as compared with the preadolescent sample. The vertical heights of the upper and lower lips were also significantly greater in the adults. The means for upper and lower lip lengths were larger in the adults than in the preadolescents by 3.0 mm and 14.0 mm, respectively.
51 8
_=..
..;Z,.linski, N a n d a , a n d .._,.__Kaoila
The findings of this study were compared with those of Subtelny, 2 Bishara et al.,6 as well as selected relevant measurements from other authors. 7'9't6 These comparisons are summarized in Table II. The three angles of convexity assessed in previous investigations were the internal angles formed between two lines intersecting at pronasale, subnasale, or A point. For comparison with findings of the present study these angles were converted into the superior angle by subtracting the means obtained by the previous investigators from 180 ~ The means found by Subtelny'- for skeletal convexity and soft tissue convexity excluding the nose in both age groups, as well as the total soft tissue convexity in adults, were similar to those determined in the present investigation. On the other hand, values defined by Bishara et al. 6 for the total soft tissue convexity, soft tissue convexity excluding the nose and Z angle, diffei'cd from those found in this study. Variation in Z angle values found by Merrifield 9 in adolescents ages 11 to 15 years old and the findings in preadolescent boys o f the present investigation can be attributed tO the fact that his subjects had been treated t o specific dentoalveolar standards and also to the age differences o f the two samples. Similarly, growth of ihe nose-and chin could explain the differences in estheiic plane values in the adult male subjects o f the present study at a mean age of 26.2 years as compared with those at age 18 years observed by Kapila 7 and Nanda et al. 19 Some o f the variations between the present investigation and the other studies may have arisen because o f differences in the selection and ages of samples evaluated and the landmarks used. The combined male and female data provided by Merrifield9 and Neger 16 may have attributed to further variations between their findings and those o f this investigation. Although the present study did not include a female sample, it is reasonable to expect sex differences in soft tissue facial contours, rendering the normative values on the basis o f pooled samples unreliable.
Sagittal facial p r o p o r t i o n s Ratios or proportions are an effective method for defining balanced facial dimensions as they compensate for extremes in sizes and do not rely on absolute millimetric measurements for establishing norm values. Several vertical and transverse proportions have been proposed previously m'lT'ts and have become an accepted method for evaluation o f facial balance. In this study three sagittal variables were determined for the specific purpose of defining proportions of an esthetic and harmonious face in the anteroposterior plane. The nasal depth, nose to most protrusive lip, and chin to most protrusive lip ratios were found to be 2 . 1 : 1 . 0 : 1 . 2 in preadolescent boys and 1 . 8 : 1 . 0 : 0 . 3 in men (Fig. 1, D). The difference in the two ratios also indicates
Am. J. Orthod. Dentofac. Orthop. June 1992
the variation in soft tissue profiles between children and adults. SUMMARY
Lateral head cephalograms of 31 preadolescent boys and 29 men, who had well-balanced and esthetic facial profiles, were evaluated to define norms for several integumental variables. In addition, analysis to determine age differences in these variables was performed with a two group t test. A method for evaluating sagittal proportions o f the nose, lips, and chin was also proposed. REFERENCES I. BurstoneCJ. lntegumentalcontourandextensionpatterns. Angle Orthod 1959;29:93-104. 2. Subtelny JD. A longitudinal study of soft tissue facial structures and their profile characteristics defined in relation to underlying skeletal structure. AM J OR'moP 1959;45:481-507. 3. Subtelny JD. The soft tissue profile, growth and treatment changes. Angle Orthod 1961;31:105-22. 4. Mauchamp O, Sassouni V. Growth and prediction of skeletal and soft tissue profiles. AM J ORTIIOD1973;64:83-94. 5. Chaconas SJ, Bartroff JD. Prediction of normal soft tissue facial changes. Angle Orthod 1975;45:12-25. 6. Bishara SE, ttession TJ, Peterson LC. Longitudinal soft tissue profile changes. AM J OR'atoP 1985;88:209-23. 7. Kapila S. Lip profile growth changes: a longitudinal cephalometric study from 7 to 18 years. [Thesis] Oklahoma City: University of Oklahoma, 1986. 8. pelion WJ, Elsasser WA. Studies of dentofacial morphol~y IV. Profile changes among 6,829 white individuals according to age and sex. Angle Orthod 1955;25:199-207. 9. Merfifield LL. Tile profile line as an aid in critically evaluating facial esthetics. A.',IJ OR'troD 1966;52:804-22. 10. Ricketts RM. Esthetics, environment, and the law of lip relation. A.',t J ORvlIOD1968;54:272-89. 11. Thurow RC. Atlas of orthodontic principles. St. Louis: CV Mosby, 1970:30-89. 12. Downs WB. Variations in facial relationships: their significance in treatment and prognosis. AM J ORTIIOD1948;34:811-40. 13. Wisth PJ. Changes of the soft tissue profile during growth. Trans Europ Orthod Soc 1972:123-31. 14. Wisth PJ, Boe OE. The reliability of cephalometrie soft tissue measurements. Archs. Oral Biol 1975;20:595-99. 15. ttillesund E, Fjeld D, Zachrisson BU. Reliability of soft tissue profile in cephalometrics. AM J O~THOD1978;74:537-50. 16. Neger M. A quantitative method for the evaluation of soft tissue profile. AM J OR'I-ItOD1959;45:738-51. 17. Legan ilL, Burstone CJ. Soft tissue cephalometric analysis for ortho,gnathic surgery. J Oral Surgery 1980;38:744-51. 18. Ricketts RM. The divine proportion. A new movement in orthodontics. In: Balbach DR, ed. Proceedings of the foundation for orthodontic research, 1980-81. Ann Arbor: ELS Lithographics, 1982:29-43. 19. Nanda RS, Meng HP, Kapila S, Goorhuis Y. Growth changes in the soft tissue facial profile. Angle Orthod 1990;60:177-90. Reprint requests to:
Dr. Ram S. Nanda College of Dentistry" The University of Oklahoma P.O. Box 26901 1001 Shanton L. Young Blvd. Oklahoma City, OK 73190
