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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 11  |  Issue : 1  |  Page : 1-8

Comparative evaluation of perioral soft tissue of skeletal normal Class I and Class II Division 1 subjects: A lateral cephalometric study


Department of Orthodontics and Dentofacial Orthopaedics, CSMSS Dental College and Hospital, Aurangabad, Maharashtra, India

Date of Submission04-Dec-2019
Date of Acceptance13-Mar-2020
Date of Web Publication10-Apr-2020

Correspondence Address:
Dr. Nikita Babasaheb Sanap
CSMSS Dental College, Staff Quarter, Flat No. 6, Kanchanwadi, Aurangabad - 431002, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijor.ijor_43_19

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  Abstract 

Objective: This study aimed to evaluate and compare shape variability of soft-tissue outline of skeletal Class II Division 1 patients with various vertical patterns (low, moderate, and high SN-MP angles) and skeletal normal Class I occlusion patients and to evaluate correlative skeletal and dental variables affecting soft-tissue thickness using cephalometric analysis.
Materials and Methods: Sixty patients were selected with Class I normal occlusion and Class II Division 1 and divided into four groups based on horizontal and vertical skeletal pattern (SN-MP angles) on lateral cephalograms as Group I (normal occlusion), Group II-L (low angle <27°), Group II-N (normal angle 27°–36°), and Group II-H (high angle ≥ 37°). The correlation and multiple linear regression analysis were used to determine skeletal and dental variables influencing soft tissue characteristics.
Results: The skeletal Class II patients with a high mandibular plane angle had significantly greater values than the skeletal Class II patients with a low mandibular plane angle for basic lower lip thickness and lower lip length. The measurements in perioral soft-tissue thickness were correlated with an inclination of the upper and lower incisors along with facial depth and facial length in skeletal Class II Division 1 patients.
Conclusion: Lip strain, lip thickness, and dental inclination must be evaluated based on various skeletal patterns for balanced perioral muscle activity.

Keywords: Perioral soft tissue, SN-MP angles, vertical pattern


How to cite this article:
Khatri JM, Sanap NB. Comparative evaluation of perioral soft tissue of skeletal normal Class I and Class II Division 1 subjects: A lateral cephalometric study. Int J Orthod Rehabil 2020;11:1-8

How to cite this URL:
Khatri JM, Sanap NB. Comparative evaluation of perioral soft tissue of skeletal normal Class I and Class II Division 1 subjects: A lateral cephalometric study. Int J Orthod Rehabil [serial online] 2020 [cited 2020 May 29];11:1-8. Available from: http://www.orthodrehab.org/text.asp?2020/11/1/1/282184


  Introduction Top


Balance and harmony of the soft-tissue facial profile in orthodontic treatment depends mainly on the characteristics of overlying soft tissues according to the horizontal and vertical skeletal patterns. For patient desire, in orthodontic treatment planning, it is necessary to consider facial appearance determined by the soft-tissue analysis as well as underlying skeletal pattern.[1] Facial balance depends on the form, proportion, and position of its various anatomical units. Chin plays a vital role in balancing facial profile in the lower third of the face.[2]

A lot of research showed that soft tissues have a significant factor in determining a patient's final facial profile. Due to the increasing acceptance of shift in paradigm, the diagnosis and orthodontic treatment planning are established predominantly by soft-tissue considerations than skeletal/dental relationships. Hence, the need for soft-tissue consideration is of significant use in orthodontics.[3]

According to studies, about 25% of patients exhibit skeletal Class II malocclusion and soft-tissue discrepancies. Not only skeletal patterns but also dental positions influence the soft-tissue profile, and hence, in this study, the focus is on Class II Division 1 patients with different skeletal patterns.[4]

Class II malocclusion may result from numerous combinations of skeletal and dental disorders. Class II Division 1 malocclusion can be developed due to three reasons such as, protrusive maxilla, retrusive mandible, or combination.[5]

Utsuno et al. stated that soft tissue was significantly thicker in Class II patients than Class I patients. Largest differences were observed in Class II with points subnasale, labrale superius, labiomentale, and pogonion. In Class II, soft tissue was thinner than in other skeletal classes in the upper lip region and thicker in the mental region.[6]

The vertical dimension influences orthodontic diagnosis and treatment planning in growing and adult patients. Variations in thickness, length, and tonicity of the soft tissues may affect the position of and the relationships among the facial structures, thereby affecting facial esthetics.[7] According to Kamak, significant differences in soft tissue thickness was greater in men than in women.[8]

The aim of this study was to evaluate and compare extraoral soft-tissue changes in skeletal Class II Division 1 patients with various vertical growth patterns and skeletal Class I patients. Along with the measurements of thickness and vertical length of the perioral soft tissues, a ratio of soft-tissue contour to hard-tissue contour was conceived to comprehend the interrelationship between soft tissues and underlying hard tissues. This study was carried out because no such studies were carried out or available in the past in the local population.


  Materials and Methods Top


This prospective study was carried out to compare and evaluate soft-tissue characteristics of skeletal Class II Division 1 patient s with various vertical patterns with normal skeletal Class I occlusion patients. From the outpatient department of the department of orthodontics and dentofacial orthopedics of the age group of 16–35 years, having Angle's Class I normal occlusion and Class II Division 1 malocclusion, 60 patients were selected. Lateral cephalograms of each patient were obtained.

Prior to commencement, patients were elucidated and their willingness to participate in this study was affirmed. Informed consent/parental permission was obtained from all patients who met inclusion criteria, and information regarding the purpose, procedure, and risks of the study was given to the patients/parents.

Inclusion and extrusion criteria for patient selection were selected as follows:

Inclusion criteria

Each group included patients with:

  1. Patients with the age group of 16–35 years
  2. Full set of permanent teeth excluding the third molars
  3. Bilateral Class I molar relationship and Class I canine relationship with normal overjet (2 mm) and overbite (2 mm). Skeletal Class I, natural dentition, no alteration of facial morphology, no crowding, and no spacing of dental occlusion
  4. Bilateral angle's Class II molar relationship with proclination of anteriors (Division 1), Class II canine relationship, and mild crowding
  5. Healthy patients with no systemic diseases
  6. Patients with healthy periodontal condition.


Exclusion criteria

  1. Patients with facial asymmetry
  2. History of previous orthodontic or orthognathic surgery
  3. Craniofacial anomaly
  4. Patients with large overjet exceeding 10 mm
  5. Anterior open bite
  6. patients with lips open on radiographs
  7. Patients with cysts or tumors of either jaws or other pathology
  8. Patients with unerupted, partially erupted, supernumerary, or over-retained deciduous teeth
  9. Extensive caries with anterior and posterior teeth
  10. Fractured anterior teeth.


The skeletal and dental measurements

These included SNA, SNB, ANB, Wits appraisal (AO-BO), SN-MP, FMA, facial length (S-Gn), Facial depth (N-Go), facial height ratio (S-Go/N-Me), U1 to SN, U1 to NA (in millimeters and degrees), L1 to NB (in millimeters and degrees), IMPA, interincisal angle, maxillary incisor exposure, overjet, and overbite [Figure 1].
Figure 1: Soft-tissue landmarks and definitions of measurement for cephalometric analysis. Linear measurements: 1: Basic upper lip thickness, linear distance from 3 mm below A-point to subnasale, 2: Upper lip thickness, linear distance from the most prominent labial point of the maxillary incisor (U1) to labrale superius (Ls), 3: Upper lip strain, the difference between basic upper lip thickness and upper lip thickness, 4: Lower lip thickness, linear distance from the most prominent labial point of the mandibular incisor (L1) to labrale inferius (Li), 5: Basic lower lip thickness, linear distance from B-point to the deepest point of the labiomental fold, 6: Chin thickness-H, linear distance from pogonion to its sagittal projection on the soft tissue (Pog-Pog'), 7: Chin thickness-V, linear distance from menton to its vertical projection on the soft tissue (Me-Me'), 8: Subnasale to H-line, 9: Lower lip to H-line, 10: Ricketts' E line to the upper lip, 11: Ricketts' E-line to lower lip, 12: Upper lip length, vertical distance from subnasale to the lowest point of the upper lip (Stms) perpendicular to the Frankfort horizontal plane (FH plane), 13: Lower lip length, vertical distance from the highest point of the lower lip (Stmi) to the soft-tissue B-point perpendicular to the FH plane, 14: Soft-tissue contour (red dottedline), total length of lower facial profile (subnasale-Me'), 15: Hard tissue contour (blue dotted line), total length of hard tissue contour (anterior nasal spine-Me), and contour ratio was a percentage ratio of soft-tissue contour to hard-tissue contour, 16: Nasolabial angle, 17: H-angle, angle formed by H-line and soft-tissue nasion-Pog line

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The soft-tissue measurements

These included upper lip thickness, lower lip thickness, chin thickness, subnasale to H-line, lower lip to H-line, Ricketts' E-line to the upper lip and to lower lip, upper lip length, lower lip length, soft-tissue contour (subnasale-Me), hard-tissue contour (anterior nasal spine-Me), nasolabial angle, and H-angle.

As per inclusion and exclusion criteria, 15 patients were selected for each group which were grouped as follows:

  1. Group I – Class I normal occlusion – 15 samples


  2. Group II – Angle's Class II Division 1 malocclusion.


    1. Group II – Low angle: Angle's Class II Division 1 with SN-MP <27° – 15 samples
    2. Group II – Normal angle: Angle's Class II Division 1 with SN-MP – 27°–36° – 15 samples
    3. Group III – High angle: Angle's Class II Division 1 with SN-MP >37° – 15 samples.


Statistical analysis

The data were collected, tabulated, and statistically analyzed using the SPSS 20 version software to get their interpretation. The mean, standard deviation, and P value were calculated for each parameter in each group. To find the significant differences between the groups, ANOVA test was used. Post hoc Scheff's test was used for the comparison between the groups. To determine dental and skeletal variables affecting soft-tissue characteristics, Pearson correlation analysis and multiple linear regression analysis were carried out.P < 0.05 was considered statistically significant.


  Results Top


The average intraclass correlation coefficient of the cephalometric analysis was 0.93 (range, 0.89–0.99) for the linear and angular measurements. The error of the method was measured according to Dahlberg's formula 26: 0.45 mm for linear measurements and 1.2 for angular measurements. Kolmogorov–Smirnov normality tests showed that the data had a normal distribution.

Upper lip thickness was less in Group II-N and II-H. Subnasale to H-line and H-angle was also increased in Group II-N and II-H. Chin thickness was less in II-N and II-H. Lower lip length was less in Group II [Table 1].
Table 1: Soft-tissue measurements (mean and standard deviation) for all patients

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In our study, on comparison of soft-tissue measurements in Group I and Group II-L, II-N, and II-H, upper lip thickness was significantly less in Group II-N and II-H compared to Group I. Upper lip strain was significantly present in Group II compared with Group I. Group II-H had more upper lip strain values than Group II-L and II-N [Table 1].

Upper lip strain was significantly present in Group II-H with a significant value of 0.06 compared to Group II-N and II-L. Upper lip thickness was found to be less in Group II-H and II-N than II-L. Lower lip length was significantly short in Group II-H than Group II-L and II-N. Nasolabial angle was found to be more acute in high-angle cases [Table 1].

In our study, on comparison of dental and skeletal measurements in Group I and Group II-L, II-N, and II-H, significantly more values were found with U1-SN, U1-NA, L1-NB, IMPA, overjet, overbite, ANB, AO-BO, FMA, and facial height ratio in Group II-L, II-N, and II-H than Group I. Upper and lower incisors were more proclined in Group II compared to Group I. The mandible was more retruded in Class II cases than Class I. Facial height ratio was significantly more in Group II-L [Table 2].
Table 2: Skeletal and dental measurements (mean and standard deviation) for all patients

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On comparison of dental and skeletal measurements in Group II-L with Group II-N and II-H, significant values were found between the Groups II-L and II-H. High-angle cases showed more proclined upper incisors than low-angle and normal-angle cases [Table 2].

In our study, in multiple linear regression analysis, independent variables used in each regression group were selected according to the correlation test. Lower lip thickness was influenced by overbite, FMA, and facial depth. Subnasale to H-line was significantly affected by L1-NB, facial length, and facial depth. Lower lip to H-line was dependant on L1-NB, IMPA, overbite, facial length, facial depth, and facial height ratio. Upper and lower lip lengths were affected by U1-NA, upper incisor exposure, and facial depth. Soft-tissue contour was influenced by the facial depth and hard-tissue contour was affected by overbite and facial depth. Overbite and ANB angle influenced the nasolabial angle. H-angle was dependant on U1-NA and upper incisor exposure [Table 3]. Comparison of soft tissue measurements with dental measurements showed that lower lip thickness was correlated with overbite. Subnasale to H line was correlated with L1-NB. Lower lip to H line was correlated with L1-NB, IMPA and overbite. Rickett's E line to upper lip was correlated with U1-NA. Rickett's E line to lower lip was correlated with U1-NA, L1-NB, IMPA and overbite. Upper lip length was correlated with U1-NA and U1 exposure. Lower lip length was correlated with overbite. Hard tissue contour and nasolabial angle were also correlated with overbite. H angle was correlated with U1-NA and U1 exposure [Table 4].
Table 3: Results of multiple linear regression

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Table 4: Pearson correlation coefficients of Group II between soft-tissue thickness and skeletal and dental variable

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  Discussion Top


It has been reported that soft tissue more closely determines therapeutic modifiability. Thus, soft-tissue analysis is a critical part of orthodontic decision-making, and this can be accomplished by recognizing the differences in soft-tissue thickness in each skeletal classification.[2]

Soft-tissue cephalometric values are as important as hard-tissue values when assessing the success of treatment. One of the predominant goals of orthodontic treatment is to improve facial esthetics.[9] Sometimes, the esthetic result is more important to the patient than the occlusal changes. Hence, good occlusion and improved facial appearance are distinct yet parallel objectives of orthodontic treatment.[4]

In our study, when the assessment of soft-tissue measurements in Class I normal occlusion was carried out, and Class I normal occlusion patients showed normal mean values of upper lip thickness, lower lip thickness, upper lip strain, chin thickness, subnasale to H-line, lower lip to H-line, Rickett's E-line to upper lip, and Rickett's E-line to lower lip, and nasolabial angle and H-angle in accordance with normal values of 15, 15, 2, 10–12, 12, 0, −4, and − 2 mm, and 90°–110° and 7°–15°, respectively.

Studies reported that upper and lower lips were retruded according to Rickett's E-line to the upper lip and Rickett's E-line to the lower lip with mean values of −5.4 and −4.1 mm, respectively, in Class I normal occlusion patients.[10]

In our study, when the assessment of soft-tissue measurements in Group II-L, II-N, and II-H (Class II Division 1 low angle, normal angle and high angle) was carried out, it was observed that upper lip thickness was less in Group II-N and II-H. Subnasale to H-line and H-angle was also increased in Group II-N and II-H. Upper and lower lips were found to be protruded in Group II-L, II-N, and II-H in relation to Rickett's E-line. Chin thickness was less in II-N and II-H. Lower lip length was less in Group II.

In our study, on comparison of soft-tissue measurements in Group I and Group II-L, II-N, and II-H, upper lip thickness was significantly less in Group II-N and II-H compared to Group I. Upper lip strain was significantly present in Group II compared with Group I. Group II-H had more upper lip strain values than Group II-L and II-N. Upper and lower lips in relation to Rickett's E-line were significantly protruded in Group II-H, II-N, and II-L compared to Group I.

Upper and lower lips were observed more protruding in Class II Division 1 cases in Chinese and European population.[5],[11] Upper and lower lips in relation to E-line were also found to be protruded in Class II Division 1 with low, medium, and high angle patients studied by Mobarak et al.,[12] with more value in Class II Division 1 low-angle (2.18 mm) patients than medium-angle (1.63 mm) and high-angle (1.74 mm) patients.

In our study, H-angle was significantly increased in Group II compared to Group I, and lower lip length was significantly decreased in Group II-N and II-H compared to Group I with values of 11.43 mm in II-N, 11.27 mm in II-H, and 14.23 mm in Group I.

Upper lip strain, soft tissue subnasale to H-line, upper lip thickness and H-angle were found to be more among the Lucknow population.[13]

Other studies concluded that H-angle was significantly larger in Class II Division 1 patients than Class I patients, and the upper lip was more protrusive in Class II Division 1 patients.[11],[14]

We found that the characteristics of soft-tissue measurements according to vertical patterns (SN-MP) were distinct, with statistical differences in upper lip strain and lower lip length. Upper lip strain was significantly present in Group II-H with a significant value of 0.06 compared to Group II-N and II-L. Upper lip thickness was found to be less in Group II-H and II-N than II-L. Lower lip length was significantly short in Group II-H than Group II-L and II-N. Nasolabial angle was found to be more acute in high-angle cases.

In our study, dental and skeletal measurements in Class I normal occlusion showed significantly normal values with slight proclination of lower incisor and decreased interincisal angle with normal overjet and overbite. Group II-L, II-N, and II-H cases showed proclined upper and lower incisors, increased overjet and overbite, prognathic maxilla, and retrognathic mandible.

In our study, on comparison of dental and skeletal measurements in Group I and Group II-L, II-N, and II-H, significantly more values were found with U1-SN, U1-NA, L1-NB, IMPA, overjet, overbite, ANB, AO-BO, FMA, and facial height ratio in Group II-L, II-N, and II-H than Group I. Upper and lower incisors were more proclined in Group II compared to Group I. Mandible was more retruded in Group II than Group I. Facial height ratio was significantly more in Group II-L. Young Joo Lee[1] found that L1-NB value was statistically lower in Group I than Group II-N and II-H.

On comparison of dental and skeletal measurements in Group II-L with Group II-N and II-H, significant values were found between the Groups II-L and II-H. Upper incisors were found to more proclined in high-angle cases than low-angle and normal-angle cases. Proclined lower incisors were found with II-L and II-H patients.

In our study, in multiple linear regression analysis, independent variables used in each regression group were selected according to the correlation test. Lower lip thickness was influenced by overbite, FMA, and facial depth. Subnasale to H-line was significantly affected by L1-NB, facial length, and facial depth. Lower lip to H-line was dependant on L1-NB, IMPA, overbite, facial length, facial depth, and facial height ratio. Upper and lower lip lengths were affected by U1-NA, upper incisor exposure, and facial depth. Soft-tissue contour was influenced by the facial depth and hard-tissue contour was affected by overbite and facial depth. Overbite and ANB angle influenced the nasolabial angle. H-angle was dependant on U1-NA and upper incisor exposure.

Upper and lower lip thickness was influenced by L1-NB and overjet, and upper lip strain was associated with U1-NA and overjet according to other studies.[1] The measurements of perioral soft tissue were correlated with inclination and anteroposterior position of incisors along with the facial length and facial depth.

In this study, the sample size was too small to achieve statistical power to test each male and female group separately. Further comparative studies with larger samples and more additional skeletal classification could be conducted to increase statistical power. Different racial comparisons can also be studied.


  Conclusion Top


  1. Class II Division 1 malocclusion patients with various vertical pattern were found to have more soft-tissue imbalance than normal Class I occlusion patients
  2. Lower lip thickness and lower lip length were found to be significantly greater in skeletal Class II Division 1 patients with high mandibular plane angle compared to low mandibular plane angle
  3. Class II Division 1 patients had significantly protruded upper and lower lips and H-angle was significantly greater
  4. Upper lip strain was evident in all Class II Division 1 cases
  5. The inclination of upper and lower incisors with facial depth and facial length significantly affected perioral soft-tissue measurements in skeletal Class II Division 1 patients.


Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Lee YJ, Park JT, Cha JY. Perioral soft tissue evaluation of skeletal Class II Division 1: A lateral cephalometric study. Am J Orthod Dentofacial Orthop 2015;148:405-13.  Back to cited text no. 1
    
2.
Subramaniam S, Karthi M, Kumar KP, Raja S. Comparison of soft tissue chin prominence in various mandibular divergence patterns of Tamil Nadu population. J Indian Acad Dent Spec Res 2016;3:39.  Back to cited text no. 2
  [Full text]  
3.
Yelampalli MR, Rachala MR. Timely management of developing class III malocclusion. J Indian Soc Pedod Prev Dent 2012;30:78-84.  Back to cited text no. 3
  [Full text]  
4.
Hoffelder LB, de Lima EM, Martinelli FL, Bolognese AM. Soft-tissue changes during facial growth in skeletal Class II individuals. Am J Orthod Dentofacial Orthop 2007;131:490-5.  Back to cited text no. 4
    
5.
Rana N, Qu YY, Wei Y, Liu L. Comparison of cephalometric hard and soft tissues of adolescents with angle Class II Division 1 malocclusion between Northern Chinese population and Northern Indian population. Chin J Dent Res 2017;20:33-42.  Back to cited text no. 5
    
6.
Utsuno H, Kageyama T, Uchida K, Yoshino M, Oohigashi S, Miyazawa H, et al. Pilot study of facial soft tissue thickness differences among three skeletal classes in Japanese females. Forensic Sci Int 2010;195:165.e1-5.  Back to cited text no. 6
    
7.
Macari AT, Hanna AE. Comparisons of soft tissue chin thickness in adult patients with various mandibular divergence patterns. Angle Orthod 2014;84:708-14.  Back to cited text no. 7
    
8.
Kamak H, Celikoglu M. Facial soft tissue thickness among skeletal malocclusions: Is there a difference? Korean J Orthod 2012;42:23-31.  Back to cited text no. 8
    
9.
Holdaway RA. A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part I. Am J Orthod 1983;84:1-28.  Back to cited text no. 9
    
10.
Hwang HS, Kim WS, McNamara JA Jr. Ethnic differences in the soft tissue profile of Korean and European-American adults with normal occlusions and well-balanced faces. Angle Orthod 2002;72:72-80.  Back to cited text no. 10
    
11.
Bishara SE, Jakobsen JR, Vorhies B, Bayati P. Changes in dentofacial structures in untreated Class II division 1 and normal subjects: A longitudinal study. Angle Orthod 1997;67:55-66.  Back to cited text no. 11
    
12.
Erbay EF, Caniklioǧlu CM, Erbay SK. Soft tissue profile in Anatolian Turkish adults: Part I. Evaluation of horizontal lip position using different soft tissue analyses. Am J Orthod Dentofacial Orthop 2002;121:57-64.  Back to cited text no. 12
    
13.
Hassan AH. Cephalometric characteristics of Class II division 1 malocclusion in a Saudi population living in the western region. Saudi Dent J 2011;23:23-7.  Back to cited text no. 13
    
14.
Subtelny JD. A longitudinal study of soft tissue facial structures and their profile characteristics defined in relation to underlying skeletal structures. Am J Orthod 1959;45:481-507.  Back to cited text no. 14
    


    Figures

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    Tables

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



 

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