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 Table of Contents  
ORIGINAL ARTICLE
Year : 2015  |  Volume : 27  |  Issue : 3  |  Page : 366-371

Correlation of morphological variants of soft palate and types of malocclusion: A digital lateral cephalometric study


Department of Oral Medicine and Radiology, Dasmesh Institute of Research and Dental Sciences, Faridkot, Punjab, India

Date of Submission29-Mar-2015
Date of Acceptance07-Nov-2015
Date of Web Publication25-Nov-2015

Correspondence Address:
Esha Garg
Department of Oral Medicine and Radiology, Dasmesh Institute of Research and Dental Sciences, Faridkot - 151 203, Punjab
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-1363.170451

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   Abstract 

Aims and Objectives: The morphology of soft palate has variable presentations on lateral cephalometry. The aim of our study was to investigate the correlation between various shapes of soft palate and types of malocclusion in different gender groups among North Indian individuals. Materials and Methods: The study sample comprised randomly selected 250 healthy North Indian individuals (125 males and 125 females) seeking orthodontic treatment for malocclusion without any speech abnormality or any other syndromes or diseases and with age ranging from 14 to 28 years. Clinically, in all subjects, the type of malocclusion was examined and categorized according to Angle's classification of malocclusion. The morphological variants of soft palate were also assessed on digital lateral cephalogram and were allocated to one of the six patterns as described by You et al. The differences in the proportion of each type were studied and variation of malocclusion and soft palate morphology between gender groups was also assessed. The results obtained were subjected to a statistical analysis to find the correlation between variants of the soft palate and types of malocclusion in different gender groups. Results: In our study, the frequency of rat tail (37.2%) type of soft palate was seen in highest proportion, whereas the frequency of distorted S-shape (6.80%) was least in both the genders. Angle's class II malocclusion (51.2%) was the most common, followed by class I (43.2%), whereas class III (5.6%) was found to be the least prominent type in both the genders. Patients with Angle's class I malocclusion were most frequently found to have rat tail type soft palate, those with Angle's class II had leaf-shaped soft palate, and those with Angle's class III had crooked shaped soft palate. Angle's class II and class III malocclusions were significantly correlated with soft palate shapes, whereas Angle's class I malocclusion was highly significantly correlated with the shape of soft palate. Conclusion: It was found in our study that there was a significant correlation between variants of soft palate and types of malocclusion.

Keywords: Digital lateral cephalometry, malocclusion, morphology, soft palate


How to cite this article:
Samdani D, Saigal A, Garg E. Correlation of morphological variants of soft palate and types of malocclusion: A digital lateral cephalometric study. J Indian Acad Oral Med Radiol 2015;27:366-71

How to cite this URL:
Samdani D, Saigal A, Garg E. Correlation of morphological variants of soft palate and types of malocclusion: A digital lateral cephalometric study. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2021 Oct 28];27:366-71. Available from: https://www.jiaomr.in/text.asp?2015/27/3/366/170451


   Introduction Top


The soft palate is a mobile flap suspended from the posterior border of the hard palate, sloping down and back between the oral and nasal parts of the pharynx. It is a thick fold of mucosa enclosing an aponeurosis, muscular tissue, vessels, nerves, lymphoid tissue, and mucus glands. [1] It participates in most of the oral functions, especially velopharyngeal closure which is related to the normal functions of sucking, swallowing, blowing, and pronunciation. Soft palate dysfunctions are frequently seen in cleft lip and palate patients, enlarged adenoids, obstructive sleep apnea syndrome (OSAS), snoring, poorly retained maxillary denture, and skeletal craniofacial malocclusion. [2],[3],[4] The palate is formed by the fusion of three components, namely, two palatal processes and the primitive palate, which is formed by the frontonasal process. The intramembranous ossification occurs in the mesoderm of palate to form the hard palate, whereas the soft palate is formed in the posterior region where the ossification does not occur. The most important muscle for velopharyngeal closure is the levator veli palatini (LVP). [3] Often the normal anatomy and any other anomaly of soft palate help in diagnosis and successful treatment of many intricate cases. Apart from evaluation of abnormalities, diversity in radiographic appearance of soft palate morphology has remained unrecognized. Numerous studies have been done in past toward the dimensional analysis of soft palate and its surrounding structures, but little attention has been paid toward the morphological variants of soft palate and configuration. You et al. [2] classified the soft palate into six morphological types (Type 1: Leaf shaped/lanceolate shaped; Type 2: Rat tail shaped; Type 3: Butt-like shaped; Type 4: Straight line shaped; Type 5: S-shaped/distorted soft palate; and Type 6: Crooked shaped) by observing the image of soft palate on lateral cephalograms. Pépin et al. observed that the "hooked or S-shaped" appearance of the soft palate in awake patients indicated a high risk of OSAS. [5],[6]

Malocclusion can present itself in numerous ways and is also frequently seen in patients with cleft lip and palate, enlarged adenoids, OSAS, and snoring. Angle classified malocclusion as follows:

  1. Class I (neutral occlusion): Alteration of tooth position in which there is a normal anteroposterior relationship between the maxilla and the mandible. The triangular ridge of the mesiobuccal cusp of the upper first permanent molar occludes in the mesiobuccal groove of the first lower permanent molar. Therefore, a person who has the aforementioned molar relationship and shows one or more of the characteristics such as rotation, diastema, crossbite, open bite, deep bite, and/or dental arch atresia is considered as having class I.
  2. Class II (Distocclusion): Malocclusion in which a "distal relationship" of the mandible is observed in respect to the maxilla. The first lower permanent molar mesiobuccal groove occludes posterior to the mesiobuccal cusp of the upper first permanent molar, where division 1 is the distocclusion in which the upper incisors are typically projected and division 2 is the distocclusion in which the upper central incisors are nearly in their anteroposterior normal position or present a mild retroclination, while the upper lateral incisors have a labial and mesial inclination.
  3. Class III (mesiocclusion): Malocclusion presenting the mandible "mesial" to the maxilla.


The mesiobuccal groove of the lower first permanent molar occludes anterior to the upper first permanent molar mesiobuccal cusp. [7] The purpose of present study was to investigate the correlation between various shapes of soft palate on lateral cephalogram and types of malocclusion in different gender groups of North Indian individuals who came for orthodontic treatment and whose age ranged from 14 to 28 years.


   Materials and Methods Top


Two hundred and fifty North Indian subjects (125 males and 125 females) who came to the Department of Oral Medicine and Radiology with the complaint of malocclusion and sought orthodontic treatment for the same from June 2014 to January 2015 were randomly selected and included in this study. Firstly, the type of malocclusion was examined clinically in all the subjects and was categorized according to Angle's classification of malocclusion. Informed written consent was obtained from each subject, and ethical clearance was obtained from the Institutional Ethics Committee (FSDCRI/IEC/2013/009; dated: 10.08.2013). Later, digital lateral cephalograms were obtained by using Allengers-Alldent HF machine. Then, lateral cephalometric analysis was performed to evaluate the morphology of soft palate, as it is a relatively inexpensive method and provides a good assessment of the soft-tissue elements. All the lateral cephalograms were taken with the patients standing upright in a natural head position and they were instructed to occlude their molars and breathe through their nose, so as to allow the same observation of the mobile sites of the soft palate and the upper airway, by one trained radiographer using the same digital radiographic machine. A tube potential of 72-76 kV, a tube current of 10 mA, and an exposure time of 2 s were used to optimize the contrast of the digital images. The digital radiographs were processed and viewed by using dental imaging software (FCR PRIMA Console Software V1.1). All the radiographs were analyzed and categorized into six types according to the soft palate morphology [Figure 1]. Various shapes of soft palate were traced by using Windows 7 paint software. All the collected data were analyzed using the IBM SPSS Statistics 20.0 Data Editor software (Microsoft Corporation Inc., Chicago, IL, USA). A cross-tab was composed by dividing the subjects based on (1) the type of malocclusion and (2) the shape of soft palate, in order to compare the correlation between various shapes of soft palate and types of malocclusion. Pearson's correlation and t-test (2-tailed) were used to evaluate the relationship among variables in the cross-tabs.
Figure 1: Various shapes of soft palate: (a) Type 1: Leaf shaped; (b) Type 2: Rat tail shaped; (c) Type 3: Butt-like shaped; (d) Type 4: Straight line shaped; (e) Type 5: Distorted S-shaped; (f) Type 6: Crooked shaped

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   Results Top


By examining the oral cavity intraorally, we classified the malocclusion into three categories: Angle's class I, class II, and class III. We preferred primary classification only for easy understanding, as further classification (i.e. division 1, division 2, and subdivision) is based on proclination and retroclination of anterior teeth, which have no effect on the shape of soft palate. Shape of soft palate depends on the posterior teeth positioning, molar relation, and jaw positioning. Angle's class II malocclusion (51.20% of cases) was the most common among both genders, followed by class I (43.20% of the cases), whereas class III (5.60% of cases) was found to be least prominent type [Table 1]. By observing the shapes of soft palate on digital lateral cephalogram, we employed the classification of soft palate given by You et al. to categorize the soft palate into six types, on the basis of radiographic appearance. In our study, the following were observed: Type 1: leaf shaped/lanceolate shaped in which the middle portion of the soft palate was elevated to both the naso- and the oro-sides (23.60% of cases); Type 2: Rat tail shaped in which the soft palate showed inflated anterior portion and free margin with an obvious coarctation (37.20% of cases); Type 3: Butt-like soft palate which showed a shorter and fatter velum appearance with no distinct difference of width of the anterior portion to the free margin (8.40% of cases); Type 4: Straight line shaped (13.20% of cases); Type 5: S-shaped/distorted soft palate (6.80% of cases); and Type 6: Crooked appearance in which the posterior portion of the soft palate appeared crooked anterio-superiorly (10.80% of cases). Distribution and proportion of these are presented in [Table 2].
Table 1: Gender distribution of patients with different malocclusions and intergroup correlation

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Table 2: Distribution of shapes of soft palate among both the genders and intergroup correlation

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The correlation between both the genders with the shapes of soft palate and types of malocclusion was done using t-test. The shapes of soft palate were insignificantly correlated (P > 0.05) among both the genders. Rat tail type of soft palate was most frequently found in both the genders, whereas the frequency of distorted S-shape was least in both the genders. Angle's classification of malocclusion was also insignificantly correlated (P > 0.05) among both the genders. Comparison between the type of malocclusion and the frequency of shapes of soft palate revealed that butt-like, distorted S-shaped, and leaf-shaped soft palate were found to be most frequent in Angle's class II malocclusion, whereas crooked and rat tail were found mostly in class I malocclusion. The straight line shape was found frequently in class I and II types. To assess the significance between Angle's malocclusion and shapes of soft palate, Pearson's correlation was applied. The shape of soft palate was significantly correlated with (P = 0.010) Angle's malocclusion types. Crooked shaped, leaf-shaped, and straight line soft palates were significantly (P < 0.05) correlated, whereas distorted S-shape showed a highly significant correlation (P = 0.000) with the types of malocclusions [Table 3]. Patients with class I malocclusion were most frequently found to be associated with rat tail type, class II malocclusion with leaf-shaped soft palate, and class III malocclusion with crooked shaped soft palate. Class II and class III malocclusion were significantly correlated with soft palate shapes, whereas class I malocclusion was highly significantly correlated with the shapes of soft palate.
Table 3: Distribution of patients with different malocclusions according to shapes of soft palate and their intergroup correlations

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   Discussion Top


The lateral cephalogram is the most common diagnostic radiograph used in clinical orthodontics. Cephalometric analysis is a commonly accepted technique for evaluation of soft palate in both normal individuals and in those with cleft palate and OSAS because of its easy availability, cost effectiveness, and relatively good assessment of soft tissue and its surrounding structures. [7],[8],[9],[10] Radiologic studies of soft palate morphology may greatly facilitate to diagnose a variety of neurologic, inflammatory, and neoplastic disorders of the adult soft palate. The dimensional analysis of the soft palate and its surrounding structures, especially the velar length and width, has been studied; nevertheless, the variety of velar morphology which is the most logical cause of different dimensions on the soft palate has been frequently overlooked. Even after closure of the soft tissue defect in cleft patients, normal function of the soft palate is frequently not achieved and velopharyngeal insufficiency (VPI) with hypernasal speech ensues in 30% or more of patients. [9],[11],[12] Cohen et al. suggested that one of the several explanations for this surgically successful, yet functionally compromised repair may be the difference in morphology of the soft palate and other associated structures in these patients from that of normal subjects. Hence, presurgical evaluation of soft palate morphology will aid in the success of surgery. [13],[14],[15],[16] In our study, type 2 (rat tail shaped) soft palate was the most frequent type (37.20% of the cases). But a previous study by You et al. described leaf-shaped soft palate to be the classic velar morphology. This variation may be due to the fact that most of our study cases had malocclusion requiring orthodontic treatment. Obstructive sleep apnea (OSA) is characterized by the recurrent occlusion of the upper airways resulting from the inspiratory collapse of the pharyngeal walls during sleep. Etiological or predisposing factors for OSA are still debated. There is an increased incidence of OSA in middle-aged adults. It was found that pharyngeal morphology is not immutably established during childhood and adolescence, but changes throughout adult life. There is a tendency toward longer and thicker soft palate and narrower oropharynx during adulthood, which may explain the possible increased incidence of OSA and related disorders occurring later in life. Pépin et al. found "hooked" appearance of the soft palate in awake patients, which indicated a high risk for OSAS. [5] You et al. found that the hooked appearance of the soft palate corresponded to S-shaped soft palate according to their classification. In our study, the type 5 S-shaped soft palate was found only in few cases (6.80%). [2],[17],[18],[19] Pépin et al. described hooking of soft palate as angulations of about 30° between the distal part of the uvula and the longitudinal axis of the soft palate. They hypothesized that soft palate hooking results in a sudden and major reduction in oropharyngeal dimensions, thus increasing upper airway resistance and transpharyngeal pressure gradient resulting in pharyngeal collapse. They also suggested that a hooked appearance of soft palate on images in awake patients indicates a strong possibility of OSA. The success rate of uvulopalatopharyngoplasty in patients with OSA has been variable. Pépin et al. believed that the differentiation of patients with particular anatomic features in upper airway may be important for any future developments in successful surgical therapy for OSAS. [5],[20]

Like soft palate dysfunctions, malocclusion is also frequently seen in patients with cleft lip and palate, enlarged adenoids, OSAS, and snoring. As discussed earlier, Angle classified malocclusion into class I, class II, and class III malocclusion. [7] In the current study, Angle's class II malocclusion [60 males and 68 females (128)] was the most common among both the genders, followed by class I malocclusion [60 males and 48 females (108)], whereas class III malocclusion [5 males and 9 females (14)] was found to be the least prominent type. Rat tail type of soft palate [44 males and 49 females (93)] was most frequently found in both the genders, whereas the frequency of distorted S-shape [10 males and 7 females (17)] was least in both the genders. Other variants of soft palate including leaf-shaped soft palate [31 males and 28 females (59)], straight line shaped soft palate [13 males and 20 females (33)], crooked shaped soft palate [13 males and 14 females (27)], and butt-like shaped soft palate [14 males and 7 females (21)] were found. Patients with class I malocclusion were most frequently found to be associated with rat tail type (63 of 108), class II malocclusion with leaf shape (47 of 128), and class III malocclusion with crooked shaped soft palate (5 of 14). Class II and class III malocclusions were significantly correlated with soft palate shapes (P < 0.05), whereas class I malocclusion was highly significantly correlated with the shapes of soft palate (P = 0.00).


   Conclusion Top


There was a significant correlation between the variants of soft palate and the types of malocclusion in North Indian subjects. The knowledge of morphological variants of the soft palate helps to get a better understanding of the velopharyngeal closure and also helps the clinician in successful functional and structural repair in cases of cleft palate and in the etiological study of OSAS, snoring, and other conditions. But the pattern of soft palate does not play any role in the management of different malocclusions.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
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    Tables

  [Table 1], [Table 2], [Table 3]



 

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