|Year : 2012 | Volume
| Issue : 4 | Page : 343-348
Paradental cyst of the first molar: Report of a rare case with bilateral presentation and review of the literature
AE Borgonovo, P Reo, GB Grossi, C Maiorana
Department of Oral Surgery, University of Milan, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
|Date of Web Publication||19-Mar-2013|
Via Wildt 14, 20131 Milan
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The paradental cyst is a lesion classified and recognized by World Health Organization quite recently, which is related to an inflammatory process, especially pericoronitis, involving a tooth in eruption. The aim of this article is to report a rare bilateral case of paradental cyst. An 8-year-old boy presented to the Oral Surgery Department, Dental Clinic, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Fondazione Ospedale Maggiore Policlinico, University of Milan, with the complaint of swelling over the buccal gingiva of his unerupted lower left first molar. Radiographs revealed a radiolucency involving the bifurcation and root area of teeth 36 and 46. The cysts were enucleated, maintaining the affected teeth in site; microscopic evaluation revealed a chronically inflamed cyst lined by a non-keratinized stratified squamous epithelium; the histopathology associated with macroscopic and radiographic examinations permitted the definitive diagnosis of a paradental cyst on the mandibular left and right first molars. The most recent literature shows the rarity of the paradental cyst occurring with bilateral localization. Because the paradental cyst can present variable clinical and radiographic signs, it is mandatory to correlate all clinical, radiographic, and histological data to obtain a definitive diagnosis.
Keywords: Bilateral cyst, mandibular disease, oral surgery, paradental cyst
|How to cite this article:|
Borgonovo A E, Reo P, Grossi G B, Maiorana C. Paradental cyst of the first molar: Report of a rare case with bilateral presentation and review of the literature. J Indian Soc Pedod Prev Dent 2012;30:343-8
|How to cite this URL:|
Borgonovo A E, Reo P, Grossi G B, Maiorana C. Paradental cyst of the first molar: Report of a rare case with bilateral presentation and review of the literature. J Indian Soc Pedod Prev Dent [serial online] 2012 [cited 2020 Feb 28];30:343-8. Available from: http://www.jisppd.com/text.asp?2012/30/4/343/108940
| Introduction|| |
The first clinical and histological description of a paradental cyst was reported by Main  in 1970. The condition was initially described as an inflammatory collateral cyst, but the diagnosis has caused many controversies in the literature. The current nomenclature was suggested by Craig  in 1976.
According to the World Health Organization (WHO) histological typing of odontogenic tumors, the paradental cyst is defined as "a cyst occurring near to the cervical margin of the lateral aspect of a root as a consequence of an inflammatory process in a periodontal pocket. A distinctive form of the paradental cyst occurs on the buccal and distal aspects of erupted mandibular molars, most commonly the third molars, where there is an associated history of pericoronitis." 
The etiology of these cysts is still debated, but it is believed that they originate from the reduced epithelium of enamel , or from the inflammatory proliferation of epithelial rests of Malassez , that come from the superficial mucosa of a tooth in eruption (pericoronitis).  They represent beyond 5% of all odontogenic cysts. ,
The major clinical feature of the paradental cyst is the presence of a recurring inflammatory periodontal process, usually a pericoronitis. Apart from acute episodes, this cyst presents only a few signs and mild symptoms, including discomfort, tenderness, moderate pain, and in some cases, suppuration through the periodontal sulcus. ,,
The aim of this work is to present a rare case of bilateral paradental cyst in a young patient affecting the buccal aspect of lower first molars, discussing diagnosis, treatment, and radiographic findings of the case.
| Case Report|| |
An 8-year-old boy was referred to Oral Surgery Department, Dental Clinic, IRCCS Fondazione Ospedale Maggiore Policlinico, University of Milan, Italy, with the complaint of swelling over the buccal gingiva of his unerupted lower left first molar. Clinically, there was mild edema in the overlaying mucosa distal to the second deciduous molar, showing a bluish color [Figure 1]. The evaluation of the panoramic radiography [Figure 2] disclosed a well-defined semilunar-shaped radiolucency, demarcated by a fine radiopaque line, on the buccal aspect of the unerupted lower left first molar [Figure 3]. Observing closely the radiograph, a second lesion was evident on the buccal aspect of the partially erupted right lower first molar, but less defined than the previous.
|Figure 2: Panoramic radiograph shows a well-defined semilunar-shaped radiolucency, demarcated by a fine radiopaque line on the buccal aspect of the left and right lower first molars|
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Computed tomography showed and confirmed the presence of bilateral lesions to the lower first molars [Figure 4]; in both cases, the margins of radiolucent lesions were delimited by a thin layer of denser bone on the buccal aspects, revealing the presence of the cysts and their relations to both first and right lower first molars; the cysts were extended from the cement-enamel junction to the lower root margins, measuring about 10 mm in the largest extension.
|Figures 4: Computed tomography shows that the margins of radiolucent lesion were delimited by a thin layer of denser bone on the buccal aspect|
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Electric pulp test for left lower first molar, partially erupted, was positive.
Clinical, radiographic, and anamnestic findings suggested an initial diagnosis of paradental cyst.
We decided for a surgical removal of the cysts under general anesthesia, planning to maintain the affected teeth.
The surgical approach was a full-thickness trapezoidal flap, with gingival crevicular incision and vertical releasing incisions; buccal ostectomy was done, care was taken to preserve a sufficient band of cortical bone in the coronal aspect. The cysts have been exposed and then enucleated trough the access previously created [Figure 5]. Having done an irrigation with sterile saline, the suture was carried out with silk 4/0.
Histologically, the cyst capsule was lined by a proliferating, non-keratinized, stratified squamous epithelium, showing as arcading. The cystic wall consisted of a dense, mature fibrous connective tissue, with an intense chronic inflammatory reaction mainly near the epithelium [Figure 6].
The histopathology associated with macroscopic and radiographic examinations permitted the definitive diagnosis of a paradental cyst on the mandibular left and right first molars.
Follow-up is still ongoing, but the panoramic radiography and clinical examinations, performed about 1 year after surgery, evidence the complete regression of the lesion and the correct eruption of the mandibular permanent left and right first molars [Figure 7], [Figure 8].
|Figure 7: Panoramic radiograph 1 year after surgery, indicating a complete regression of the two lesions and the correct eruption of the mandibular left and right first molars|
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|Figures 8: Intraoral view 1 year after surgery, showing the correct eruption of mandibular left and right first molars|
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| Discussion|| |
An inflammatory etiopathogenic nature of paradental cysts has been widely discussed in the literature. Initially, all reported cysts involved lower third molars with inflammatory processes  and when the lower first permanent molars of children aged between 6 years and 8 years were involved, these cysts were called mandibular infected buccal cysts.  This type of cystic lesion was considered a distinct clinical entity by some authors, , but this concept was never fully accepted. 
The paradental cyst is considered a rare lesion; it was included in the WHO histological typing of odontogenic tumors for the first time in 1992, although it has been described in several clinicopathological studies in specialized journals since 1970. ,,, The relatively recent characterization of this cyst can be a contributing factor to its non-recognition; on the other hand, it has been speculated that this lesion has been underdiagnosed. Lindh and Larsson  believe that the paradental cyst has been misdiagnosed as a dentigerous cyst, lateral radicular cyst, or merely as pericoronitis or some other entity related to inflammatory conditions of the dental follicle. Another fact that could result in the underdiagnosis of paradental cysts is that histopathological analysis of extirpated follicular sacs is rarely done.
The prevalence of paradental cysts is low compared to other cysts, representing 3-5% of all odontogenic cysts. ,,, In the mandible, this lesion was detected in only 26 (0.9%) of the 2700 cyst cases studied by Magnusson and Borrman,  who ascribed the low prevalence to several possible misdiagnoses. Specifically in regard to the lower third molars, this can be considered the second most frequent cyst, representing up to 25% of the cystic lesions associated with these teeth, although they represented only 1.6% of the cystic lesions analyzed by Colgan et al. 
The paradental cyst is localized exclusively in the mandibular region, almost always on the distal or vestibular side of a completely or partially erupted molar, but always vital. Although the mesial surface could be involved very rarely, , the lingual aspect is never interested. More than 60% of the cases of paradental cysts are associated with the lower third molars. 
Since the radiological features are different according to the tooth involved,  we can distinguish the paradental cysts developed on the first and second inferior molars, also called as "juvenile paradental cysts,"  from those involving the inferior third molar.
The medium age of the patients with paradental cyst localized at the lower first molar is 8-9 years, whereas cysts localized to the second molar appear between 13 years and 20 years of age. Bilateral localizations are marked in 23.6% of the cases. 
The clinical symptoms and signs are those of the periodontitis and are common to both localizations, while the onset of a vestibular swelling seems to be associated exclusively to the paradental cysts that involved the first molar. 
Since the lesion is localized on vestibular aspect of the roots, the involved molar is usually tilted so that the root apices are adjacent to the lingual cortex with the crown showing buccal tipping. 
The nearly exclusive involvement of the vestibular surface would be explained by the fact that the mesio-buccal cuspids are the first to perforate the oral mucosa during the eruption, and therefore, the first to be exposed to the oral ambient, as described by Stoneman et al.
It has been stated that the radiographic image of the paradental cyst involved the first or second molar, and is always characterized by a well-defined radiolucency associated with the roots on the buccal aspect. ,
The medium age of the patients with paradental cysts localized at the lower third molar is approximately 25-30 years, with a distal or disto-vestibular localization to the affected tooth; bilateral localizations are marked just in 4.1% of the cases.  In these cases of paradental cyst, usually a history of recurrent pericoronitis is reported and there is often the presence of a communication between the periodontal pocket and the cyst. The cortical expansion of the bone is not so frequent like in the forms previously described, and the majority of lesions do not exceed 15 mm of diameter. 
The etiology of paradental cysts is of an inflammatory nature, as shown by the histological findings of odontogenic epithelium proliferation, presence of an inflammatory infiltrate, and occasional hyaline changes in blood vessel walls. ,,,, However, there are controversies surrounding the origin of the lining epithelium. According to Souza et al.,  most cases of paradental cysts stem from the proliferation of reduced epithelium of the enamel organ, probably caused by inflammatory stimuli originating from the junction of the epithelium of the cystic capsule with the gingival epithelium. Colgan et al.  and Lim and Peck  also believe that this cyst arises from reduced epithelium of the enamel organ. The epithelial remnants of Malassez seem to be the most unlikely origin, although they may unreasonably explain cysts located near the roots. 
In this article, the authors present a case of bilateral paradental cyst involving both the left and right mandibular first molar. In both cases, the radiographic image of these lesions revealed a well-defined radiolucency associated with the roots on their buccal aspect.
The differential diagnosis included the radicular cyst, odontogenic keratocyst, lateral periodontal cyst, gingival cyst, dental follicles, and the dentigerous cyst.
The most recent literature shows the rarity of the paradental cyst occurring with bilateral localization; some authors  report only seven cases of bilateral involvement, including lesions occurring on first, second, and third molars; a more detailed analysis on 342 cases carried out by Philipsen et al.  reveals only 23.6% of bilateral occurrence for paradental cysts on first and second mandibular molars and 4.1% for those involving third molars. Considering the low prevalence of the paradental cyst (3-5% of all odontogenic cysts), we can assert that the bilateral occurrence is very rare.
In our case, the second lesion on the right side was noted on radiographs (and confirmed only by computed tomography); for this reason, it is generally recommended that the contra-lateral tooth should be carefully evaluated for a second lesion.
Most studies ,,,, report that a positive electric pulp test is a diagnostic criterion for paradental cyst. The diagnosis would be a lateral radicular cyst if the associated tooth is non-vital. 
The initial diagnosis of paradental cyst was made considering the anamnestic, clinical, and radiological features. Only the enucleation of cyst without extraction of the adjacent tooth was done in both the cysts. Most reports ,,,, show that if the tooth involved is the first or the second molar, the treatment of choice is enucleation of the cyst without the extraction of the tooth, whereas surgical removal of the tooth and the paradental cyst has been considered the best case solution when the involved tooth is a third molar. ,, Pompura et al.  presented 44 cases treated by enucleation without extraction. Packota et al.  successfully treated five cases of paradental cyst involving the mandibular first molar with enucleation of the cyst without extraction. In Wolf and Hietanen's report,  of all the cases of mandibular infected buccal cyst (paradental) associated with the first molar (three cases) and the second molar (three cases), four were treated without extraction. In Vedtofte and Praetorius's  series involving the mandibular first and second molars, 11 of the 13 cases treated with preservation of the involved tooth had successful outcome. In all cases, recurrence is rare, provided that the lesion has been completely removed. ,,,,
The histopathological features of the paradental cyst are identical to the radicular cyst and to those of other inflammatory odontogenic cysts; microscopic examination shows a fibrous connective tissue capsule invaded by a lymphocytic inflammatory infiltrate, lined by a hyperplastic, non-keratinized, stratified squamous epithelium; in the case that we described, both the cysts capsule were lined by a proliferating, non-keratinized, stratified squamous epithelium, showing as arcading. The cystic wall consisted of a dense, mature fibrous connective tissue, with an intense chronic inflammatory reaction mainly near the epithelium, supporting a definitive diagnosis of a paradental cyst.
The paradental cyst can present variable clinical and radiographic signs,  in addition to being confounded with the radicular cyst at the microscopic level; for these reasons, it is mandatory to correlate all clinical, radiographic, and histological data to obtain a definitive diagnosis. Surgical findings, such as bony cavitation, cystic content, and location of lesion adherence, can give some important clues. Enucleation of the lesion with the maintenance of the associated tooth can be indicated when the first or second molars are involved. ,,,,
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
|This article has been cited by|
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| ||Borgonovo, A.E., Grossi, G.B., Maridati, P.C., Maiorana, C. |
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