Growth-related changes of skeletal and upper-airway features in bilateral cleft lip and palate patients

Introduction

The craniofacial morphology of subjects with cleft lip and palate differs from that of subjects without clefts. Subjects with bilateral cleft lip and palate tend to have maxillary retrognathism, a smaller mandible with an obtuse gonial angle, greater anterior upper and lower facial heights, and retroclined maxillary incisors. The purposes of this research were to compare the skeletal and upper-airway features of subjects with bilateral cleft lip and palate with the same features in control subjects without clefts and to determine the growth-related changes at different growth stages.

Methods

The sample comprised 212 subjects divided into 2 groups: 68 with bilateral cleft lip and palate, and 144 controls without clefts; each group was further divided into 4 subgroups according to growth stage using the cervical vertebral maturation stage method. The subgroups were defined as early childhood (stage 1), prepubertal (stage 2), pubertal (stage 3), and postpubertal (stage 4). The cephalometric variables were evaluated with 2-way analysis of variance and the Bonferroni test.

Results

Maxillary position showed no significant differences between the male groups. The maxilla was more prognathic at stage 2 and became more retrognathic at stages 3 and 4 in the females. The mandible was more retrusive in the bilateral cleft lip and palate subjects at stage 1 in males and at stages 3 and 4 in females. ANB was larger at stages 1 and 2, and it became similar to the controls at stages 3 and 4 in male and female bilateral cleft lip and palate subjects. Vertical growth was seen in the bilateral cleft lip and palate subjects regardless of sex, and no change was observed with age. Posterior airway space was narrower in all stages (except for stage 1 in females). Middle airway space was wider after stage 1 in the male and female bilateral cleft lip and palate subjects. Inferior airway space was narrower in the male bilateral cleft lip and palate patients at the early childhood and pubertal stages.

Conclusions

Age- and sex-dependent differences in skeletal morphology and upper-airway widths of the bilateral cleft lip and palate subjects were identified when compared with the control subjects without clefts.

Highlights

  • Craniofacial morphology was compared in patients with cleft lip and palate and controls.

  • Age- and sex-dependent differences were identified.

  • With age, the maxilla became more retrusive in the cleft subjects.

  • Bilateral cleft patients had Class II skeletal relationships when young and Class I later.

  • Vertical growth occurred in cleft subjects, regardless of sex.

The craniofacial morphology of subjects with cleft lip and palate differs from that of subjects without clefts. In subjects with bilateral cleft lip and palate (BCLP), maxillary retrognathism, a smaller mandible with an obtuse gonial angle, greater anterior upper and lower facial heights, and retroclined maxillary incisors are observed.

In the sagittal relationships, the positions of the maxilla and the mandible influence the upper-airway space. In healthy subjects, airway dimensions are influenced not only by the position of the jaws but also by age. The volume of the airway increases from 7 to 18 years of age in both female and male subjects, with male patients having a faster rate. In female subjects, the length of the airway increases from 7 to 15 years of age without further lengthening after 15 years of age, whereas it continues to increase up to 18 years of age in male subjects. The upper-airway width increases from 6 to 18 years of age in both sexes.

BCLP is seen less commonly than unilateral cleft lip and palate. Few studies pertain to BCLP, and changes in upper-airway dimensions in subjects with BCLP have not been investigated comprehensively. Studies on airways have focused on either unilateral or mixed samples of patients with cleft lip and palate or adult BCLP patients. Therefore, the purposes of this study were to compare the skeletal and upper-airway features in subjects with operated BCLP with growth-matched control subjects without clefts and to determine whether the growth-related changes occur in the upper airway at different maturation stages. The null hypotheses were that skeletal and upper-airway features of operated BCLP patients do not differ from the controls and do not change with growth.

Material and methods

This study consisted of a total of 212 lateral cephalometric radiographs of patients with BCLP and noncleft control (NCC) patients who had never had orthodontic treatment. The BCLP group included 68 subjects, and the NCC group included 144 subjects. Ethical approval for the study was obtained from Hacettepe University in Ankara, Turkey (reference number GO 13/126-13).

The inclusion criteria for the BCLP group were (1) bilateral cleft lip and palate, (2) no other associated craniofacial anomalies, (3) no previous orthodontic treatment, and (4) primary surgical interventions by the same operator. The radiographs, which were insufficient in terms of landmark identification, were not included. All patients had received cheiloplasty and palatoplasty. Lip repair was done at approximately 3 months of age with Mulliken and modified Millard procedures. The hard palate was repaired at approximately 12 months of age with a 2-flap palatoplasty.

All patients selected for the BCLP group were of Turkish origin. The group was divided into 4 subgroups according to their growth level. The growth maturation levels of patients were expressed on the lateral cephalograms using the cervical vertebral maturation (CVM) method, determined by Franchi et al. The subgroups were then defined as early childhood, prepubertal, pubertal, and postpubertal to place the patients in their correct CVM stage. Patients younger than 7 years of age were assigned to the early childhood stage, and the remaining patients were assigned to the prepubertal, pubertal, and postpubertal stages. The early childhood stage (stage 1) included 16 subjects (<7 years old), the prepubertal stage (stage 2) comprised 25 subjects (CVM stages 1 and 2), the pubertal stage (stage 3) included 13 subjects (CVM stages 3 and 4), and the postpubertal stage (stage 4) consisted of 14 subjects (CVM stages 5 and 6).

The NCC group consisted of the lateral cephalometric radiographs of 144 subjects without clefts; 124 of them, who were selected from the archives of the Department of Orthodontics at Hacettepe University, were of Turkish origin. Because of the lack of files of subjects without clefts at early childhood ages, 20 lateral cephalograms of Class I subjects without clefts were obtained from several growth studies (Michigan, Forsyth, and Iowa) in the Craniofacial Growth Legacy Collection of the American Association of Orthodontists Foundation. All radiographs were sent to the primary investigator (B.A.-G.) as encoded high-resolution JPEG files.

The inclusion criteria for the NCC group were (1) Class I skeletal pattern (ANB, 2° to ≤6° for patients at stage 1; ANB, 1° to ≤4° for patients at other stages), (2) Class I molar relationship, and (3) no previous orthodontic treatment. The radiographs, which were low quality, were not included.

The NCC group was also divided into subgroups using the CVM method. The control group included 20 subjects in stage 1, 37 subjects in stage 2, 45 subjects in stage 3, and 42 subjects in stage 4 according to their maturation levels.

The male and female compositions of the BCLP and the NCC groups were evaluated separately. Age and sex distributions for both groups are presented in Table I .

Table I
Age and sex distributions of the groups
Study sample CVM stage BCLP NCC
n = 68 Age (y) n = 144 Age (y)
Males
1 11 4.8 ± 0.9 7 4.9 ± 0.7
2 19 8.7 ± 1.7 22 11.1 ± 2
3 9 14.1 ± 1.6 26 14.1 ± 1.3
4 10 19.2 ± 3.5 19 20.2 ± 4.7
Total 49 11 ± 5.5 74 13.9 ± 5.3
Females
1 5 4.6 ± 0.9 13 5.2 ± 0.9
2 6 9.3 ± 1.6 15 10 ± 1.6
3 4 11.8 ± 1.3 19 12.7 ± 1.2
4 4 23.3 ± 5.7 23 18.5 ± 3.6
Total 19 11.5 ± 7.2 70 12.6 ± 5.4

Values are mean ± SD.

Cephalometric variables representing skeletal pattern were assessed by the cephalometric analysis of Steiner. Analysis of pharyngeal airway size was based on the method of Mochida et al. All lateral cephalometric radiographs were traced manually, and all angular and linear measurements were done by 1 author (B.A.-G.) and reviewed by the senior investigator (M.A.) to check the accuracy of landmark identification. Magnification of the cephalometric images was adjusted according to the appropriate enlargement factor for each lateral cephalometric film. Both skeletal and pharyngeal airway size measurements are presented in Figure 1 . For the upper-airway measurements, the Frankfort horizontal plane was used as the horizontal reference plane. All measurements were made between the posterior pharyngeal wall and designated landmarks parallel to the Frankfort horizontal plane. Posterior airway space (PAS) was defined as a line that passed through the posterior nasal spine, superoposterior airway space (SPAS) was defined as a line passing through the middle of the line from the posterior nasal spine to the tip of the soft palate, middle airway space (MAS) was defined as a line passing through the tip of the soft palate, inferior airway space (IAS) was defined as a line that passed through the most anteroinferior point on the body of the second cervical vertebra, and epiglottic airway space (EAS) was defined as a line that passed through the tip of the epiglottis.

Fig 1
Skeletal measurements: 1 , SNA, angle between the SN and NA planes; 2 , SNB, angle between the SN and NB planes; 3 , ANB, angle between the NA and NB planes; 4 , FMA, angle between the Frankfort horizontal and mandibular planes. Upper-airway measurements: 5 , PAS, the anteroposterior depth of the pharynx measured between the posterior pharyngeal wall and the posterior nasal spine on a line parallel to the Frankfort horizontal plane that runs through the posterior nasal spine; 6 , SPAS, the anteroposterior depth of the pharynx measured between the posterior pharyngeal wall and the dorsum of the soft palate on a line parallel to the Frankfort horizontal plane that runs through the middle of the line from the posterior nasal spine to the tip of the soft palate; 7 , MAS, the anteroposterior depth of the pharynx measured between the posterior pharyngeal wall and the dorsum of the tongue on a line parallel to the Frankfort horizontal plane that runs through the tip of the soft palate; 8 , IAS, the anteroposterior depth of the pharynx measured between the posterior pharyngeal wall and the surface of the tongue on a line parallel to the Frankfort horizontal plane that runs through the most anteroinferior point on the body of the second cervical vertebra; 9 , EAS, the anteroposterior depth of the pharynx measured between the posterior pharyngeal wall and the surface of the tongue on a line parallel to the Frankfort horizontal plane that runs through the tip of the epiglottis.

Statistical analysis

Descriptive statistics were expressed as means and standard deviations. The independent variables were stages (1-4) and cleft (BCLP, NCC). The dependent variables were skeletal measurements (SNA, SNB, ANB, FMA) and upper-airway measurements (PAS, SPAS, MAS, IAS, EAS). Two-way analysis of variance (ANOVA) was used to evaluate the main effects of the groups and the interaction effects between them for the skeletal and upper-airway variables ( Table II ). After analyses, the main effect that involved each independent variable and the interaction effect of that factor on the other factor was examined. Group effects were cleft type (BCLP, NCC) and stage (1-4). All 2-way ANOVA tests were performed separately by sex (male, female). When there was a significant difference among the means, the Bonferroni test was performed as post hoc multiple comparisons. P values <0.05 were considered significant.

Table II
Two-way ANOVA results for the skeletal and upper-airway variables
P value
Stage Cleft Stage-cleft
Male subjects
Skeletal variables
SNA (°) 0.057 0.878 0.306
SNB (°) 0.222 0.005 0.020
ANB (°) 0.000 0.001 0.010
FMA (°) 0.590 0.000 0.104
Upper-airway variables
PAS (mm) 0.002 0.000 0.514
SPAS (mm) 0.266 0.001 0.411
MAS (mm) 0.038 0.000 0.011
IAS (mm) 0.000 0.009 0.021
EAS (mm) 0.011 0.004 0.534
Female subjects
Skeletal variables
SNA (°) 0.000 0.038 0.001
SNB (°) 0.142 0.000 0.160
ANB (°) 0.000 0.000 0.000
FMA (°) 0.897 0.000 0.119
Upper-airway variables
PAS (mm) 0.071 0.000 0.478
SPAS (mm) 0.375 0.119 0.690
MAS (mm) 0.189 0.000 0.337
IAS (mm) 0.001 0.697 0.411
EAS (mm) 0.066 0.547 0.428

P <0.01.

P <0.05.

P <0.001.

Results

Comparisons of the skeletal and upper-airway measurements at each stage between the BCLP and NCC groups are presented in Tables III and IV . Comparisons of the measurements among the stages in the male and female BCLP and NCC groups are presented in Tables V-VIII , respectively.

Table III
Comparison of skeletal and upper-airway variables at 4 growth periods: early childhood (stage 1), prepubertal (stage 2), pubertal (stage 3), and postpubertal (stage 4) between the BCLP and NCC groups in males
Stage 1 Stage 2 Stage 3 Stage 4
BCLP NCC P BCLP NCC P BCLP NCC P BCLP NCC P
Skeletal variables
SNA (°) 81.7 ± 6.2 81.8 ± 1.2 0.977 81 ± 6.3 78.9 ± 3 0.125 77.5 ± 4.8 79.5 ± 3 0.236 78.9 ± 4.4 78.4 ± 3.4 0.774
SNB (°) 70.5 ± 7.6 77.4 ± 0.5 0.001 74.9 ± 4.8 76.1 ± 2.8 0.359 74.2 ± 3.3 76.9 ± 3 0.098 77.3 ± 6.4 76.1 ± 3.3 0.469
ANB (°) 11.3 ± 5.4 4.4 ± 1.3 0.000 6 ± 6.1 2.8 ± 0.9 0.008 3.3 ± 6.7 2.5 ± 0.7 0.613 1.6 ± 6.3 2.3 ± 0.7 0.613
FMA (°) 33.8 ± 5.9 26 ± 5.1 0.001 31.4 ± 5.5 30.3 ± 4.9 0.468 31 ± 4.2 27.4 ± 3.8 0.054 32.3 ± 4.6 27.7 ± 4.7 0.015
Upper-airway variables
PAS (mm) 15.3 ± 3.8 21.9 ± 3.2 0.000 14.4 ± 3.8 20.8 ± 3.6 0.000 18.5 ± 2.8 22.5 ± 3.2 0.003 17.3 ± 4.9 23.6 ± 2.9 0.000
SPAS (mm) 7.6 ± 2.7 9.3 ± 3.1 0.188 8.1 ± 2.5 9.4 ± 2.7 0.157 9.1 ± 4.5 10.1 ± 1.8 0.345 8.1 ± 2.6 11.4 ± 2.9 0.003
MAS (mm) 11.9 ± 2.6 11.1 ± 4.6 0.616 12.9 ± 2.5 8.6 ± 2.6 0.000 13.6 ± 5.1 8.6 ± 2.3 0.000 16.7 ± 4.8 9.3 ± 2.6 0.000
IAS (mm) 9.1 ± 1.9 13.2 ± 4 0.008 8.6 ± 2.9 9.2 ± 2.1 0.535 6.6 ± 2.7 9.7 ± 3 0.011 11.8 ± 4 10.7 ± 3.9 0.357
EAS (mm) 9.3 ± 2.2 12.2 ± 3.7 0.060 8.7 ± 2.9 9.2 ± 2.3 0.633 8.6 ± 2.8 10.6 ± 3.1 0.099 10.6 ± 4.9 12.5 ± 3.9 0.127
Values are mean ± SD.

P <0.001.

P <0.01.

P <0.05.

Table IV
Comparison of skeletal and upper-airway variables at 4 growth periods: early childhood (stage 1), prepubertal (stage 2), pubertal (stage 3), and postpubertal (stage 4) between the BCLP and NCC groups in females
Stage 1 Stage 2 Stage 3 Stage 4
BCLP NCC P BCLP NCC P BCLP NCC P BCLP NCC P
Skeletal variables
SNA (°) 80.6 ± 7.2 81 ± 3.1 0.846 83.8 ± 2.7 80.3 ± 3 0.049 76.5 ± 1.7 80.5 ± 1.7 0.049 72 ± 9.9 79.2 ± 3.2 0.000
SNB (°) 73.2 ± 5.5 76.2 ± 2.4 0.085 75.8 ± 3.8 77 ± 3.5 0.432 72.9 ± 2.8 78 ± 1.8 0.006 70.5 ± 7 76.8 ± 3.1 0.001
ANB (°) 7.4 ± 2.1 4.8 ± 1.8 0.006 8 ± 4.5 3.3 ± 1 0.000 3.6 ± 3.4 2.5 ± 0.5 0.250 1.5 ± 3.4 2.4 ± 0.6 0.366
FMA (°) 32.2 ± 12.3 27.5 ± 4.2 0.075 31.9 ± 5 28.7 ± 4.4 0.183 34 ± 4.5 25.8 ± 3.1 0.003 36.8 ± 11 25.5 ± 2.6 0.000
Upper-airway variables
PAS (mm) 16.2 ± 5.7 18.6 ± 4.4 0.223 16 ± 2.6 20.6 ± 3.5 0.012 16.5 ± 2.7 22.9 ± 3.6 0.002 17.9 ± 3.9 23.7 ± 3.1 0.004
SPAS (mm) 9.6 ± 1.8 17.4 ± 20.3 0.070 7.4 ± 3.3 9.7 ± 2.3 0.544 9.6 ± 0.8 11 ± 1.6 0.748 8.8 ± 2.8 10.5 ± 2.3 0.685
MAS (mm) 12.6 ± 4.7 10.4 ± 2.4 0.165 12.4 ± 4.1 8.1 ± 1.8 0.003 15.7 ± 3.5 9.5 ± 1.8 0.000 14.2 ± 7.9 9 ± 2.5 0.002
IAS (mm) 13.6 ± 4 11.8 ± 3.3 0.326 8.2 ± 3.1 7.7 ± 2.9 0.773 8.2 ± 2.5 10.3 ± 3.6 0.284 7.9 ± 3.2 9.5 ± 3.7 0.381
EAS (mm) 11.9 ± 3.8 10.7 ± 3.8 0.474 7.6 ± 1.9 8.9 ± 2.6 0.424 9.1 ± 2.4 11.6 ± 3.8 0.166 10.6 ± 0.8 10.2 ± 3.3 0.794
Values are mean ± SD.

P <0.05.

P <0.01.

P <0.001.

Table V
Statistical analysis of the skeletal changes among the males in early childhood (stage 1), prepubertal (stage 2), pubertal (stage 3), and postpubertal (stage 4) in the BCLP and NCC groups
Skeletal variables Group Stage 1–2 Stage 2–3 Stage 3–4
Mean difference SE P Mean difference SE P Mean difference SE P
SNA (°) BCLP −0.8 1.6 1.000 −3.4 1.7 0.286 1.4 2.0 1.000
NCC −2.9 1.8 0.716 0.6 1.2 1.000 −1.0 1.3 1.000
SNB (°) BCLP 4.5 1.6 0.036 −0.7 1.7 1.000 3.1 1.9 0.687
NCC −1.3 1.8 1.000 0.8 1.2 1.000 0.0 1.3 1.000
ANB (°) BCLP −5.2 1.5 0.003 −2.7 1.6 0.490 −1.7 1.8 1.000
NCC −1.6 1.7 1.000 −0.2 1.1 1.000 −0.2 1.2 1.000
FMA (°) BCLP −2.4 1.8 1.000 −0.4 1.9 1.000 1.3 2.2 1.000
NCC 4.3 2.1 0.255 −2.9 1.4 0.240 0.3 1.4 1.000
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Apr 6, 2017 | Posted by in Orthodontics | Comments Off on Growth-related changes of skeletal and upper-airway features in bilateral cleft lip and palate patients
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