|Year : 2019 | Volume
| Issue : 3 | Page : 203-209
Morphometric assessment of soft palate in oral submucous fibrosis using cone beam computed tomography: A cross-sectional study
Pooja Khare1, Ramachandra Reddy1, Anish Gupta2, Vijayta Sharva3, Manoj Gupta4, Pooja Singh5
1 Department of Oral Medicine and Radiology, People's Dental Academy, Bhopal, Madhya Pradesh, India
2 Department of Oral Pathology and Microbiology, People's Dental Academy, Bhopal, Madhya Pradesh, India
3 Department of Public Health Dentistry, People's Dental Academy, Bhopal, Madhya Pradesh, India
4 Public Health Dentistry, Hitkarni Dental College, Jabalpur, Madhya Pradesh, India
5 Oral Medicine and Radiology, Madhya Pradesh, India
|Date of Submission||21-Jun-2019|
|Date of Acceptance||21-Aug-2019|
|Date of Web Publication||30-Sep-2019|
Dr. Pooja Khare
Department of Oral Medicine and Radiology, People's Dental Academy, Bhopal, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Context: Oral submucous fibrosis (OSMF), a chronic disorder, presents with limited mouth opening and fibrosis of the lining mucosa of the upper digestive tract involving the oral cavity, oropharynx, and commonly the upper third of the esophagus. Studies assessing morphological changes of soft palate using cone beam computed tomography (CBCT) may construe functional alterations. Aims: The objective of our study was to assess (1) the morphological variations of soft palate, (2) its comparison with different OSMF grades and control groups by CBCT, and (3) velopharyngeal incompetency. Setting and Design: The study attributed the clinical features of OSMF based on Pindborg's classification. Patients were scanned for morphometric assessment of soft palate. Materials and Method: CBCT images of 45 OSMF patients and 45 control-group patients were analyzed using Statistical Package for the Social Sciences version 20 (SPSS Pvt Ltd. Chicago, IL, USA). Two investigators performed the morphometric analysis, and the average was taken.Statistical Analysis: Independent t-test was applied. Results: A total of 90 patients were imaged. Leaf-type morphology was the most common, and Stage III had the maximum of butt-type morphology. Mean velar width was significantly higher in the OSMF group compared to the control group. Conclusions: The study illustrated three-dimensional soft palate images including the morphology in different OSMF grades, thereby accurately measuring various parameters of soft palate. As OSMF progresses, the morphology of soft palate changes eventually from Type I to other types. Morphological changes can be reversed or arrested from further worsening if assessed in the first phase of OSMF.
Keywords: Cone beam computed tomography, cephalometry, oral submucous fibrosis, velar
|How to cite this article:|
Khare P, Reddy R, Gupta A, Sharva V, Gupta M, Singh P. Morphometric assessment of soft palate in oral submucous fibrosis using cone beam computed tomography: A cross-sectional study. J Indian Acad Oral Med Radiol 2019;31:203-9
|How to cite this URL:|
Khare P, Reddy R, Gupta A, Sharva V, Gupta M, Singh P. Morphometric assessment of soft palate in oral submucous fibrosis using cone beam computed tomography: A cross-sectional study. J Indian Acad Oral Med Radiol [serial online] 2019 [cited 2020 Jan 29];31:203-9. Available from: http://www.jiaomr.in/text.asp?2019/31/3/203/268273
| Introduction|| |
The soft palate is posterior muscular extension of hard palate, together making the oral cavity palate and the nasal cavity floor. The soft palate (velum) aids in phonation, deglutition, and velopharyngeal closure which is achieved by its sphincteric mechanism with pharyngeal walls. It can be clinically identified by change in color, and its can be measured by lateral cephalometry (LC). However, the accuracy of its dimensions including its boundaries is best studied by cone beam computed tomography (CBCT). The CBCT images are of superior quality, can be validated, and are reproducible when compared to other imaging techniques. Oral submucous fibrosis (OSMF), a chronic disorder, presents with limited mouth opening and fibrosis of the lining mucosa of the upper digestive tract involving the oral cavity, oropharynx, and commonly the upper third of the esophagus. With the advent of LC and CBCT, hard and soft palate morphology has been studied in addition to airway area and volume. In OSMF, mucosa of the oral cavity is much adversely affected leading to changes in soft palate morphology and alterations in uvula. This may lead to variation in velopharyngeal closure, thus hampering its function. Literature was searched on PubMed and Google, and soft palate morphology in normal healthy individuals and OSMF by LC was found. Studies have evaluated soft palate by CBCT in healthy individuals and oral sleep apnea by comparing its length with airway volume., However, no study to date has assessed the morphological variations of soft palate and its comparison with different OSMF grades by CBCT. Hence, this study conglomerates the use of CBCT in OSMF patients to discern morphological and functional changes of soft palate using CBCT. CBCT provides clear soft tissue detail and visibility. The objectives of the research were to (1) compare the proportion of soft palate variants between the OSMF and control-group patients, (2) compare the degree of velopharyngeal closure between these two groups, and (3) determine if there were significant correlations between different variations of soft palate morphology and the OSMF stages.
| Subjects and Methods|| |
The cross-sectional study was carried out in our institution, after procedural clearance from institutional ethics committee and research advisory committee (PDA/IEC/100/Misc/20th August). Detailed case history was obtained, and patients with other palatal defects and those undergoing treatment were excluded. A total of 45 patients, clinically diagnosed as OSMF, were included. In addition, 45 patients formed the control group. An informed consent was obtained from each of them. The hazards of radiation were explained to the patients, and preventive measures were taken. CBCT was done once, and the patients were not advised CBCT during follow-up visits considering the concepts of ALARA. Study duration was approximately 6 months. Based on Pindborg's classification, OSMF patients were graded into three stages:
Stage I: Stomatitis includes erythematous mucosa, vesicles, mucosal ulcers, melanotic mucosal pigmentation, and mucosal petechiae.
Stage II: Fibrosis occurs in healing vesicles and ulcers, which is the hallmark of this stage.
- Early lesions show blanching of the oral mucosa.
- Older lesions include vertical and circular palpable fibrous bands in the buccal mucosa and around the mouth opening or lips.
- Findings include a reduction of mouth opening, stiff and small tongue, blanched and leathery floor of the mouth, fibrotic and depigmented gingiva, rubbery soft palate with decreased mobility, blanched and atrophic tonsils, shrunken budlike uvula, and sunken cheeks, not commensurate with age or nutritional status.
Stage III: The sequels of OSMF are as follows:
- Leukoplakia is found in more than 25% of individuals with OSMF.
- Speech and hearing deficit may occur because of the involvement of tongue and the Eustachian tube More Details.
The CBCT images of OSMF and control-group patients were recorded by the digital radiographic machine Sirona Orthophos SL CBCT, 90 Kv, 10 mA, exposure time of 10 s. The patients were asked to sit up straight with the Frankfort horizontal line parallel to the floor and breathe through their nose with teeth in maximum intercuspation. Images were stored in the Digital Imaging and Communications in Medicine (DICOM) format. The soft palate morphology was observed and categorized into six types as suggested by You et al.—Type I: leaf type [Figure 1], Type II: rat-tail type [Figure 2], Type III: butt type [Figure 3], Type IV: straight-line type, Type V: s-shaped type [Figure 4], Type VI: crook shape [Figure 5]. The critical ratio between soft palate length (VL) and nasopharyngeal depth (PD), known as Need's ratio (NR), is used to ascertain velopharyngeal incompetency (VPI) if it is more than 0.7. Morphological categorization of soft palate and determination of NR was carried out. The VL was measured as a linear distance from the posterior nasal spine (PNS) to the tip of the uvula of the resting soft palate [Figure 6]. The thickest section of velum is known as velar width (VW) [Figure 7]. The PD was taken as a linear measurement from the PNS to the posterior pharyngeal wall along the palatal plane [Figure 8]. The NR was calculated for all the subjects by dividing the PD with VL. The morphometric analysis was conducted by two experienced investigators independently, and the average was considered to avoid bias. The statistical analysis was done using Statistical Package for the Social Sciences version 20 (SPSS Pvt Ltd. Chicago, IL, USA). Independent t-test was applied. The results were considered statistically significant if P was ≤ z0.05.
|Figure 1: Leaf type velar morphology showing middle portion of the soft palate elevated to both the naso- and the oro-side|
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|Figure 2: Rat-tail type velar morphology showing inflated anterior portion and the free margin with obvious coarctation|
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|Figure 3: Butt type velar morphology showing shorter and fatter velum appearance and no distinct difference in width from the anterior portion to the free margin|
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|Figure 4: S-shaped velar morphology as depicted by a distorted morphology|
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|Figure 5: Crook shaped velar morphology showing posterior portion of the soft palate crooked anterosuperiorly|
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|Figure 6: Velar length (VL): linear distance from the posterior nasal spine (PNS) to the tip of the uvula|
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|Figure 8: Pharyngeal depth (PD): linear measurement from the posterior nasal spine (PNS) to the posterior pharyngeal wall along the palatal plane|
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| Results|| |
This study attested a dominant male predilection. Out of 90 subjects (cases and controls), there were 64.4% males (n= 58) and 35.5% females (n= 32). The age range was 20–58 with a mean of 36.14 ± 8.9. Following Pindborg's classification, there were 15 patients in each of the 3 stages in the study group. Morphological analysis revealed that leaf type was the most common form 40% (n= 18), followed by rat-tail type 20% (n= 9), and butt type 17.8% (n= 8). Leaf type was commonly seen in Stage I of OSMF 22.2% (n= 10), whereas rat-tail type was seen equally in Stage I and II 8.9% (n= 4). Stage III showed a maximum of butt type morphology 11.1% (n= 5). Importantly, crook type was only seen in Stage III 6.7% (n= 3). These results were statistically significant (P< 0.05) [Table 1]. [Table 2] shows the distribution of soft palate in the two groups (OSMF and control group), where both had higher prevalence of Type I–III soft palates compared to Type IV–VI, but this was not significant (P > 0.05). S-shaped and crook type were seen in only 6.7% OSMF patients each (n= 3). These results were not significant (P > 0.05).
|Table 1: Distribution of soft palates according to the stages of OSMF in study group|
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|Table 2: Distribution of different types of soft palate in study and control group|
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Both groups were compared within the first four types of soft palate. VW, PD, and NR comparisons in leaf-type and straight-line type pattern showed statistically significant results (P< 0.05). VL in straight-line type pattern showed statistically significant results (P< 0.05). None of the other types showed statistically significant results.
Leaf type (Type I): Out of 18 patients, 10 had Stage I OSMF, followed by 5 and 3 grouped under Stage II and III, respectively. VL in study group was 35.402 mm and 35.555 mm in control group. PD was 24.085 mm in study group and 24.450 mm in control group. These results were not significant. VW was 8.801 mm in study group and 8.540 mm in control group. NR was 0.679 in study group and 0.690 in control group. The results for VW and NR were significant (P< 0.05) [Table 3].
|Table 3: Comparison of soft palate Type I and various measurements in cases and controls|
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Rat-tail type (Type II): Out of 9 patients, 4 had Stage I OSMF, followed by 4 and 1 grouped under Stage II and III, respectively. VL in study group was 34.160 mm and 34.694 mm in control group. PD was 24.560 mm in study group and 25.161 mm in control group. VW was 8.741 mm in study group and 8.460 mm in control group. NR was 0.724 in study group and 0.720 in controls. These results were not significant [Table 4].
|Table 4: Comparison of soft palate Type II and various measurements in cases and controls|
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Butt type (Type III): Out of 8 patients, 1 had Stage I OSMF, followed by 2 and 5 grouped under Stage II and III, respectively. VL in study group was 33.080 mm and 33.105 mm in control group. PD was 23.250 mm in study group and 23.304 mm in control group. VW was 9.401 mm in study group and 9.560 mm in control group which was statistically significant. NR was 0.713 in study group and 0.720 in control group which was not significant [Table 5].
|Table 5: Comparison of Soft palate Type III and various measurements in cases and controls|
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Straight-line type (Type IV): Out of 4 patients, 3 had Stage II OSMF and only 1 patient had Stage III OSMF. Though there were few cases in this morphological pattern, the results were significant for VL, VW, PD, and NR. VL was 33.727 mm in study group and 33.320 mm in control group. PD was 24.027 mm in study group and 23.500 mm in controls. VW was 8.415 mm in cases and 8.370 mm in controls. NR was 0.710 in study group and 0.700 in controls [Table 6].
|Table 6: Comparison of soft palate Type IV and various measurements in cases and controls|
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Comparisons in s-shaped and crook type could not be made due to scarcity of cases in those morphological patterns.
While comparing the VL, VW, PD, and NR in two groups it was seen that mean VW was significantly higher (P< 0.05) in OSMF group compared to the control group [Table 7].
|Table 7: Independent t-test showing the comparison of mean and SD in OSMF and control groups|
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| Discussion|| |
OSMF, first described by Schwartz in 1952, is commonly seen in young and adults and is prevalent in Southeast Asia and Indian subcontinent. It is characterized by juxtaepithelial inflammatory reaction followed by fibroelastic changes in the lamina propria. Ranganathan et al. reviewed various classifications and histopathological evaluation in OSMF. Some of the noted findings include that of Su, who reported acanthosis, Sirsat, and Khanolkar about dense collagen aggregations in submucosa with a characteristic hyaline degeneration in the connective tissue., Gupta et al. found atrophy of the muscle fibers in 9.4%, a loss of cross-striations in 13.2%, and edematous infiltration of the muscle fibers. Despite these findings, the morphological patterns of soft palate play a crucial role in velopharyngeal closure and functions which can be best analyzed by imaging techniques. The fundamental objective of OSMF treatment, whether medicinal or surgical, is to achieve functional competency. LC and CBCT have been most commonly used to assess soft palate morphology. However, CBCT provides a three-dimensional image of structures, closely representing actual or direct measurements. This is one of the premier studies evaluating morphological patterns of soft palate in OSMF and comparing them with different OSMF stages by CBCT. In our study, we observed that leaf type (also known as classic velar morphology) was most common 40% in OSMF patients, followed by rat-tail type 20%, and butt type 17.8%. Our results for leaf-type variant (the most prevalent) in study group and control group were consistent with the findings of Shankar et al. (2014), You et al. (2008) and Raja Lakshmi et al. (2016).,, Shankar et al. also observed straight-line type to be the least common and no cases in s-shaped type, whereas in our study crook type and s-shaped type were least common. Yet, More et al. (2015) concluded that butt type of morphology in normal individuals was most common, whereas Agrawal et al. found rat-tail shape to be more common in OSMF patients., These variations could be attributed since we had 15 cases in each of the stages of OSMF, whereas in other studies there was no such equal distribution. Another reason could be geographical variations.
The other interesting observations in our study were that Stage I OSMF showed maximum leaf-type pattern, followed by rat tail and straight. S and crook shaped were not seen in Stage I. This may be due to the fact that according to Pindborg's classification (1989) there is no fibrosis in Stage I, and hence the most common type is Type I, the classic velar morphology, which is also commonly seen in normal individuals. In addition, we observed that straight-line type were maximum in Stage II OSMF compared to other stages, although leaf and rat-tail type predominated. Stage III OSMF showed maximum of Butt type followed by Leaf and Crook type each. These results were similar to other studies ,, and prove that as the OSMF stage progresses, the morphology of soft palate changes eventually from Type I to other Types. Mohan et al. (2014) concluded that in the initial stages of OSMF Types I and II were more common, and with the progression of disease increased frequency of Type III and IV is noted.
As pointed out by Chaturvedi, such morphological changes may be due to:
- differential fibrosis between oral and pharyngeal surface of uvula,
- fibrosis of the mucosa overlying the soft palate and the oral surface of uvula pulling the tip of the uvula in the forward direction.
You et al. concluded that in normal individuals increase in age from preadult to adult Type III (butt type) will be transformed to Types I and II. Type III has the shortest VL. In other words, Type I and Type II are seen in normal healthy individuals or in cases where fibrosis has not extended to soft palate. When fibrosis affects soft palate and uvula, especially in Stage II and III, uvula may appear shrunken and budlike. This causes reduction in VL, leading to faulty approximation of velum and lateral and pharyngeal walls. We thus hypothesize that progression in fibrosis leads to VPI. This is the first study which assessed soft palate morphology by CBCT along with the estimation of VL, VW, PD, and NR in OSMF patients. Mean VL and mean PD reduced gradually from Type I to other variants. There was not much difference in VW among the variants. Our results were in accordance with Agrawal et al. for VL and PD but not for VW. Agarwal found least VW in butt type, whereas in our study butt type showed maximum thickness. This may be due to three-dimensional picture of shrunken soft palate and fibrosis occurring in submucosa causing it to increase in width. It was slightly more than 0.7 in all other types. Subtenly inferred that NR (PD/VL) between 0.6–0.7 is optimum for velopharyngeal function. A value above 0.7 results in VPI. We observed that the NR was within the normal range only in Type I variant. In all the other variants, it was above 0.7, thus causing difficulty in swallowing and deglutition. Overall NR was 0.7062 in OSMF patients. The results for Type I and IV were statistically significant.
The patients were treated with biweekly intralesional injection of corticosteroid and hyaluronidase, but no CBCT was advised following the principles of ALARA. There were improvements in the clinical signs and symptoms in Stage I and II patients. Few patients from Stage III showed minimal improvement and were advised surgical intervention.
This study is a hallmark, assessing three-dimensional morphological alterations in soft palate among OSMF patients. The amount of fibrosis affecting oral mucosa and the pharynx will eventually depend on whether the patient swallows or spits the juice of areca nut, and hence the results of this study need to be correlated to the same. These morphological changes can be reversed or arrested from further worsening if assessed in the first phase of OSMF. There are researches with a plethora of details on the duration and frequency of areca nut consumption and OSMF progression. This study illustrates three-dimensional images of soft palate including its morphology in different OSMF grades, thereby accurately measuring various parameters of soft palate. We believe that CBCT gives a more lifelike image compared to LC, making it a correct choice for assessing functional competencies.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published, and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]