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 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 4  |  Issue : 1  |  Page : 18-22

Paramolar tubercle (Parastyle) in primary molars of Davangere (India) children: A retrospective study


1 Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka, India
2 Department of Oral and Maxillofacial Surgery, Bapuji Dental College, Davangere, Karnataka, India

Date of Web Publication18-Feb-2015

Correspondence Address:
N B Nagaveni
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2231-6027.151615

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  Abstract 

Aim: To estimate the prevalence of paramolar tubercle (extra cusp) in primary molars of Indian children. Materials and Methods: A survey was conducted in children aged 2-8 years reporting during the period from 2006 to 2008. For recording paramolar tubercle, the definition given by Scott and Turner was employed. Subjects found with paramolar structure were further subjected to radiographic examination and impressions were made for further analysis of the paramolar tubercle. Results: Paramolar tubercle was noticed in eight patients (five boys and three girls). Among the eight patients, one patient had bilateral presence of paramolar tubercle. In seven patients, it was found on the right side and in two patients, it was found on the left side. We found type I in one case, type II in one case, type III in four cases, type IV in two cases and type V in one patient. Based on the different morphological patterns of paramolar tubercle observed during this study, we propose a new diagnostic classification system for better grading and understanding this rare dental trait, particularly for primary molars. Conclusion: As the frequency of paramolar tubercle is very rare, more studies involving different races have to be performed, rather involving individual cases, to show its unilateral/bilateral presence, sexual predominance and also to analyze the size and pattern of the paramolar tubercle.

Keywords: Accessory cusp, dental trait, paramolar tubercle, primary molar


How to cite this article:
Nagaveni N B, Umashankara K V, Poornima P, Subba Reddy V V. Paramolar tubercle (Parastyle) in primary molars of Davangere (India) children: A retrospective study. Int J Oral Health Sci 2014;4:18-22

How to cite this URL:
Nagaveni N B, Umashankara K V, Poornima P, Subba Reddy V V. Paramolar tubercle (Parastyle) in primary molars of Davangere (India) children: A retrospective study. Int J Oral Health Sci [serial online] 2014 [cited 2019 Nov 12];4:18-22. Available from: http://www.ijohsjournal.org/text.asp?2014/4/1/18/151615


  Introduction Top


A thorough understanding of crown morphology of primary molars is required for achieving a high level of success in restorative, endodontic and prosthodontic treatments. Failure to recognize variation in crown morphology can result in unusual restorative treatment outcomes. Therefore, it is imperative that a dentist be well informed and alerted to the most common possible variations.
"Paramolar tubercle" or "parastyle" or "paramolar cusp" is an accessory cusp-like structure rarely encountered in primary dentition. [1] This trait is a cingulum derivative seen on the buccal surface of the mesiobuccal cusp (paracone) of the upper molars and the buccal surfaces of the upper premolars. [1] Whereas Dahlberg [2] suggested that paramolar cusp is a term applied to any stylar or anomalous cusps, with supernumerary inclusion or eminence occurring on the buccal surfaces of both the upper and the lower premolars and molars. Its significance is not exactly known but it is reported that as paramolar tubercles arise from the buccal cingulum, these structures in the human dentition probably represent the remnants of the cingulum of mammals and the lower primates. [3] Turner and Katich [4] have classified this structure into six types based on its appearance, particularly for permanent molars.

There are no reports citing the prevalence of paramolar tubercle in the primary molars of Indian children. Also, there is no precise classification scheme for grading paramolar tubercle in primary molars. Therefore, the present study was designed and conducted to estimate the prevalence of paramolar tubercle and also to analyze the varied appearance of this structure in the primary molars. Based on different morphological appearances of the paramolar tubercle that were examined during this study, a new classification system has been proposed for grading of variable paramolar tubercle in the primary molars.


  Materials and Methods Top


The purpose of this investigation was to study the crown morphology of primary maxillary molars, with special emphasis on the prevalence of extra cusp (paramolar tubercle) on the buccal surface of the maxillary first molar. The children who reported to the outpatient department of Pedodontics and Preventive Dentistry during the period from August 2006 to November 2008 were subjected to detailed clinical examination. Age of the patients ranged from 2 to 8 years. For assessment of paramolar tubercle, the definition given by Scott and Turner [1] was employed. Patients found with paramolar tubercle were further subjected to radiographic examination and impressions were taken for detailed evaluation of the extra cusp. Based on the different paramolar tubercle appearance, a new classification system has been proposed for better grading of this structure [Table 1]. The detailed description of patients associated with paramolar tubercle is presented in [Table 2].
Table 1: Classification system for grading paramolar tubercle in the primary molars


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Table 2: Description of patients with paramolar tubercle


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  Results Top


From the survey conducted during the period from 2006 to 2008, paramolar tubercle was found in only eight patients (five boys and three girls). Among the eight patients, one had bilateral paramolar tubercle. In seven patient, the paramolar tubercles were present on the right side [Figure 1] and in two patients, the paramolar tubercles were present on the left side. One patient had other anomalies like cusp of Carabelli (bilateral). According to the new classification system, we found type I paramolar tubercle in one case [Figure 1], type II in one case [Figure 2], type III in four cases [Figure 3], type IV [Figure 4] in two cases and type V in one patient [Figure 5]. In six patients, prophylactic sealing of the developmental groove was carried out. [Figure 6] shows the overall pictures of paramolar tubercles found in our patients.
Figure 1: Type 1 paramolar tubercle in the primary right first molar (arrow)

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Figure 2: Type 2 paramolar tubercle (arrow)

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Figure 3: Cast showing Type 3 paramolar tubercle from both buccal and occlusal views

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Figure 4: Picture showing type 4 paramolar tubercle (arrow)

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Figure 5: Type 5 paramolar tubercle in 65 (arrow)

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Figure 6: Pictures showing paramolar tubercles in different patients

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  Discussion Top


As the permanent dentition succeeds the deciduous teeth, the pathologic characteristics of the permanent teeth must be more frequent and evolution must be more rapid than in the deciduous dentition. To recapitulate, and with the exception of some morphologic and number peculiarities, the primary dentition shows more stability in its characteristics and is less evolutionary than the permanent dentition. At present, pertaining to the increase of anomalies, it is often difficult to distinguish what is caused by evolution and what is the result of heredity, rare and sex. In a limited number of instances, some anomalies of permanent dentition follow those of primary dentition. For all these reasons, it is desirable that dental anthropologists take more interest in the primary dentition. [5]

Unfortunately, there are no studies that have been performed to ascertain the rare anomalies like paramolar tubercles that occur in the primary molars. Brabent [5] compared the characteristics and anomalies of the deciduous and permanent dentition. He reported that this structure was rare on the deciduous second molar. Ooshima et al. [6] studied the prevalence of paramolar tubercle and other developmental anomalies like microdontia, macrodontia, peg-shaped teeth, Carabelli's tubercle and protostylid in primary dentitions of 1650 Japanese children. They found paramolar tubercle in 2.5% (12 boys and 12 girls) of primary dentitions and 1.6% (seven males and five females) of permanent dentitions. No sex difference was demonstrated in either dentition. It was most common in the permanent dentition on the maxillary second molar and on the maxillary first molar in the primary dentition. They confirmed that the tooth with paramolar tubercle appeared to be partly related to the mesio-distal dimension of the remaining teeth, i.e., they tended to be associated with the increased tooth size.

Kustaloglu [3] analyzed the pattern and frequency of this structure for the upper primary and permanent molars in different populations. He stated that south-western Indians showed a higher occurrence in both primary and permanent molars compared with other populations like Negros, Whites, Melanesians, Filipinos, Hawaiians, Kish, Peruvians and North-western Indians. Recently, Simratvir et al. [7] studied the buccal bulge of the deciduous molars in 2016 children. Unfortunately, they have not clearly mentioned which primary molars were studied and what was the prevalence found from this study.

The literature review showed no studies to estimate the prevalence of paramolar tubercles in primary molars of the Indian population. In 2009, Nagaveni et al. [8] reported the paramolar tubercle in the maxillary primary first molars in two Indian patients. The present study is the pioneer study to show the prevalence of paramolar tubercle in the primary molars of Indian children. In this study, eight patients were found to have paramolar tubercle: Five were found in boys and three in girls. This finding was found to be in agreement with the Ooshima et al. [6] study.

An extensive review of the literature revealed no information on the grading of paramolar tubercle in primary teeth. Turner and Katich [4] have given scoring of paramolar tubercle as score 0 to 6, particularly for permanent dentition. The present study also analyzed the varying morphology of paramolar tubercle and proposed a new classification system for grading of this structure. This is the highlight of the current study, and might help in future studies involving this rare dental trait. In cases classified as types 4 and 5, further radiographic examination was carried out to assess the pulpal extension into the paramolar tubercle that revealed absence of definite pulpal space in all types 4 and 5 cases examined [Figure 7].
Figure 7: Radiographic examination revealed absence of pulp in the paramolar tubercle (arrows)

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Clinical significance of paramolar tubercle

Paramolar tubercle may present as an asymptomatic and incidental dental finding during routine dental examination. If it is of significant size, with sharp and prominent cusp, they may irritate the buccal mucosa or interfere with esthetics. Associated grooves may predispose to plaque retention and early carious lesion. No treatment is required if the paramolar tubercle is of small size and can be easily maintained. If grooves are found, prophylactic sealing can be performed, to prevent caries occurrence. Other major clinical problems that may be encountered with the paramolar tubercle in primary molars is difficult in band and stainless steel crown adaptation because of its pronounced prominence. According to Simratvir et al., [7] the type C morphological pattern can be reduced without the fear of pulpal exposure during crown adaptation. While the other type, the Type CO pattern that exhibits formatio supradentalis pattern, requires endodontic treatment before placement of crowns to facilitate proper reduction. Or, if the paramolar tubercle is very prominent, the larger crown may be required.


  Conclusion Top


Finally, it was concluded from this study that the frequency of paramolar tubercle in primary molars is very rare and, if it occurs, shows varied morphological appearance. Therefore, more studies involving different races have to be performed rather than involving individual cases to show its unilateral/bilateral prevalence and sexual and racial predominance, and also to analyze the size and pattern of the paramolar tubercle.

 
  References Top

1.
Scott GR, Turner CG. The anthropology of modern human teeth. In: Dental morphology and its variation in recent human populations. Cambridge, England: Cambridge University Press; 2000. p. 53-4.  Back to cited text no. 1
    
2.
Dahlberg AA. The paramolar tubercle (Bolk). Am J Phys Anthropol 1945;3:9-103.  Back to cited text no. 2
    
3.
Kustaloglu OA. Paramolar structures of the upper dentition. J Dent Res 1962;41:75-83.  Back to cited text no. 3
    
4.
Turner CG, Katich JF. ASU dental anthropology system. Scoring procedures for key morphological traits of the permanent dentition. Available at: http://www.archaeology.asu.edu/library/lab/chapter-nine.pdf. [Last accessed on 2013 Dec 20].  Back to cited text no. 4
    
5.
Brabant H. Comparison of the characteristics and anomalies of the deciduous and the permanent dentition. J Dent Res 1967;46:897-902.  Back to cited text no. 5
[PUBMED]    
6.
Ooshima T, Ishida R, Mishima K, Sobue S. The prevalence of developmental anomalies of teeth and their association with size in the primary and permanent dentitions of 1650 Japanese children. Int J Paediatr Dent 1996;6:87-94.  Back to cited text no. 6
    
7.
Simratvir M, Moghe G, Singh D, Dhillon K. Variation in buccal surface morphology of deciduous first molars. J Indian Soc Pedod Prev Dent 2012;30:192-4.  Back to cited text no. 7
[PUBMED]  Medknow Journal  
8.
Nagaveni NB, Umashankara KV, Radhika NB, Garewal RS. "Paramolar tubercle" in the primary dentition: Cases reports and literature review. Inter J Dent Anthropol 2009;14:12-8.  Back to cited text no. 8
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
 
 
    Tables

  [Table 1], [Table 2]



 

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