| Abstract|| |
Aim: This study aimed to analyze the prevalence of diseases related to pericoronal follicles, and assess the rate of concordance between clinical and histopathological diagnoses. Methods: Histologically, we analyzed 1,298 tissue samples surrounding the crowns of teeth that were diagnosed clinically as pericoronal follicles. In addition, we determined associations among histopathological diagnosis, patients' age and sex, tissue site, presence of nests of odontogenic epithelium, presence of reduced enamel epithelium, and presence of diffuse inflammation. Results: Odontogenic pathologies were present in 35% of the samples, and rate of concordance between clinical and histopathological diagnoses was 0.54. Probability of developing odontogenic pathologies was high in the mandibular molars (odds ratio: 2.13) and in the tissues with odontogenic epithelial remnants (odds ratio: 1.2), reduced enamel epithelium (odds ratio: 1.3), and diffuse inflammation. (odds ratio: 10.5). Conclusions: The findings of this study highlight the clinical relevance of histopathological examination of the pericoronal tissue in unerupted and partially erupted teeth for early diagnosis of pathologies because this study demonstrated the odontogenic cysts and inflammatory lesions in tissues clinically diagnosed as pericoronal follicles.
Keywords: Dentigerous cyst, diagnosis, odontogenic cysts, oral and maxillofacial pathology, oral, pericoronitis
|How to cite this article:|
da Silva VP, Meyer Gd, Daroit NB, Maraschin BJ, de Oliveira MG, Visioli F, Rados PV. Pericoronal follicles revealing unsuspected odontogenic cysts and inflammatory lesions: A retrospective microscopy study. Indian J Dent Res 2020;31:80-4
|How to cite this URL:|
da Silva VP, Meyer Gd, Daroit NB, Maraschin BJ, de Oliveira MG, Visioli F, Rados PV. Pericoronal follicles revealing unsuspected odontogenic cysts and inflammatory lesions: A retrospective microscopy study. Indian J Dent Res [serial online] 2020 [cited 2021 May 11];31:80-4. Available from: https://www.ijdr.in/text.asp?2020/31/1/80/281813
| Introduction|| |
Unerupted teeth are commonly affected by odontogenic lesions.,,, Pericoronal follicles are tissue that surround the crown of unerupted teeth, which consist of connective tissue containing nests of odontogenic epithelium. These structures are reported to have the potential to proliferate and develop into odontogenic cysts and tumors.,,,
The prevalence rate of the development of odontogenic lesions associated with impacted teeth shows discrepancy among reports in the literature; however, the overall conclusion is that their development is uncommon.,,,, Most studies have analyzed radiographic imaging data alone, including some with long-term follow-up.,,,, It is likely that many odontogenic and inflammatory lesions were not confirmed, due to absence of associated symptoms and radiographic evidence.
In routine clinical practice, tissues are further examined only under radiographic image finding of large radiolucent areas.,,, The aim of this study was to microscopically evaluate the tissues surrounding the crowns of unerupted teeth that were clinically diagnosed as pericoronal follicles.
| Methods|| |
Our institutions' Research Ethics Committee approved the study design. The study was conducted in accordance with the Declaration of Helsinki. All samples that were clinically diagnosed as pericoronal follicles, over an eight-year period, were selected from oral pathology laboratory archives. Patients' age, sex, lesion site, presence of odontogenic epithelial remnants, reduced enamel epithelium, and diffuse inflammation were recorded.
Histopathological diagnosis was established according to the following criteria: Presence of pericoronal follicles composed of fibrous connective tissue surrounding the crown of impacted tooth, possibly with myxoid changes, odontogenic epithelial remnants, and/or reduced enamel epithelium exhibiting a nest or string formation [Figure 1]a; presence of dentigerous cysts showing three or more layers of non-keratinized stratified squamous epithelium surrounding the crown of unerupted tooth, over a capsule of connective tissue of variable density, possibly containing odontogenic epithelial remnants and reduced enamel [Figure 1]b; presence of paradental cysts showing either isolated cystic stratified squamous epithelium surrounding the crown of partially erupted tooth, or in continuity with the sulcular and mucosal epithelium [Figure 1]c; and finally, tissue samples with pericoronitis showing presence of hyperplastic sulcular epithelium with exocytosis and dense, homogenous inflammatory cell infiltration in the entire area [Figure 1]d. In addition, analysis of each slide indicated the presence of reduced enamel epithelium, nests of odontogenic epithelium, and diffuse inflammation.
|Figure 1: Photomicrographs of representative cases of different histopathological diagnosis. (a) Pericoronal follicle showing reduced enamel epithelia and odontogenic epithelial remnants. (b) Dentigerous cyst showing hyperplastic non-keratinized stratified epithelium lining. (c) Paradental cyst showing cystic stratified squamous epithelium with cord-like anastomoses of intense inflammatory cells continuous with parakeratinized stratified mucosal epithelium. (d) Pericoronitis showing mucosal tissue lined by parakeratinized stratified squamous epithelium and chronic inflammatory infiltrate (H/E)|
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From a total of 7,228 specimens registered in the pathology laboratory, 1,326 samples (18.34%) were clinically diagnosed as pericoronal follicles. We excluded 28 samples either because of nonavailability of slides/blocks or because of insufficient material for further analysis. Diagnoses other than those described above were categorized as other (fragments of mucosa, giant cell lesions, blood clots, chronic non-specific inflammation). We classified the lesion site into following five categories: Mx-ICP (maxillary incisors, canines, and premolars); Mx-M (maxillary molars); Md-ICP (mandibular incisors, canines, and premolars); Md-M (mandibular molars); and SUPER (supernumerary teeth). Patients' age was classified into following four categories: 0-10, 11-20, 21-30, and 31-59 years.
Slides were assessed by two previously calibrated examiners (VPS, MGO), intra-examiner kappa values were calculated, and results >0.7 were considered as acceptable. Rate of agreement between clinical and histopathological diagnoses was calculated using prevalence-adjusted and bias-adjusted kappa (PABAK-OS) test. Other analyses such as Chi-square test, Yates' correction for continuity, Fisher's exact test, and logistic regression were performed. Results were analyzed using Statistical Package for the Social Sciences (SPSS) version 19 (Armonk, NY: IBM Corp.). Statistical significance was set at P < 0.5%.
| Results|| |
The final sample comprised of 1,298 specimens, of which, 35% had final diagnosis based on microscopy finding that differed from initial clinical diagnosis. Rate of concordance between clinical and histopathological diagnoses was 0.54 (PABAK-OS). Distribution of the five histopathological diagnostic categories is shown in [Table 1].
|Table 1: Correlation of histopathological diagnostic category with patients' sex and lesion site|
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Statistically significant association was found between patients' sex and diagnosis of paradental cysts, with female predilection (54% of female patients vs 46% of male patients). Pericoronitis was diagnosed in 52% of male patients and 48% of female patients. Pericoronal follicles and dentigerous cysts were more prevalent among women, with diagnosis in 71% of female patients and 29% of male patients [Table 1].
With regard to lesion site, 72% of patients had lesions in the mandibular third molars; whereas, at other sites, pericoronal follicle was the most frequent diagnosis. There were no cases of pericoronitis or paradental cysts in the Mx-ICP, Md-ICP, and SUPER groups [Table 1]. Analysis of age distribution showed that pericoronal follicles were more prevalent in the 11-20 years' age group, whereas, paradental cysts and pericoronitis were more common in the 21-30 years'age group [Figure 2]. Significant associations were observed between pathological diagnoses and presence of reduced enamel epithelium, odontogenic epithelial remnants, and diffuse inflammation [Figure 3].
|Figure 2: Distribution of cases based on histopathological diagnosis and age|
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|Figure 3: Correlation between diagnoses and specific histopathological findings. PF, pericoronal follicle; DC, dentigerous cyst; PC, paradental cyst; PERI, pericoronitis; REE, reduced enamel epithelium; OER, odontogenic epithelial remnants|
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Odds ratio analysis revealed that likelihood of developing pathologies was 1.13-fold higher when the tissues originated from the mandibular molar (odds ratio: 2.13); in addition, the likelihood of developing pathologies increased in the presence of reduced enamel epithelium, odontogenic epithelial remnants, and diffuse inflammation (odds ratio: 1.3, 1.2, and 10.5, respectively).
| Discussion|| |
In clinical practice, histopathological examination of pericoronal follicles is usually neglected in cases with normal radiographic findings and absence of symptoms.,, Sample size in our study (approximately 1000) was similar to those in another study regarding odontogenic lesions related to pericoronal follicles. In this study, 35% of tissue samples collected from around the crowns of unerupted teeth showed histopathological abnormalities and were diagnosed as dentigerous cysts, paradental cysts, or pericoronitis, despite absence of radiographic abnormalities, indicative of need for histopathological examination in confirmed diagnosis of clinically unsuspected lesions.
Based on previous reports, odontogenic epithelial remnants and reduced enamel epithelium that are present in pericoronal follicles have potential to develop into odontogenic cysts or tumors under exposure to certain stimuli. This was described in two cases of pericoronal follicles with histopathological diagnosis of ameloblastoma that did not show clinical or radiographic signs of disease prior to microscopic examination.
In this study, dentigerous cyst was the most frequent histopathological diagnosis. Reports lack consensus regarding criteria for differentiation of pericoronal follicles and dentigerous cysts. Currently, diagnosis of dentigerous cyst requires combined presence of clinical, surgical, radiographic, and histological characteristics compatible with the condition; in the absence of any of these features, diagnosis of pericoronal follicle should be established.,,, Alternatively, presence of stratified squamous epithelium on microscopic examination is a characteristic sign of cell activation and proliferation. This morphologic finding is sufficient for diagnosis of dentigerous cyst.,, These events could be interpreted as the initial stage of cystic development, which does not produce radiographic evidence of bone resorption. da Silva Baumgart et al. showed that the proliferative potential of reduced enamel epithelium may be similar to that of normal mucosa.
Paradental cysts and pericoronitis are more commonly associated with partially erupted molars. They result from accumulation of bacteria in periodontal tissues surrounding the crown of the tooth, causing inflammatory reactions and thus, triggering disease progression. We detected diffuse inflammation in 70.5% of samples diagnosed with paradental cysts, and in 100% of those diagnosed with pericoronitis. In addition, we observed that in the presence of inflammation, tissues surrounding the crowns of unerupted teeth had 10.5% higher probability of developing pathologies, compared with those without signs of inflammation (odds ratio: 10.5). Thus, inflammatory process is a potential influencing factor in pathogenesis of the lesions.
In our study, pathologies were more frequently found in tissue samples from patients aged 11–30 years, which is in accordance with previously reported findings.,, Moreover, with increasing age, dentigerous cysts showed higher frequency of occurrence than that of pericoronal follicles. This corroborates the hypothesis of positive correlation between duration in situ of the epithelial remnants and possibility of odontogenic lesions' development.,,,
Further evidence included finding of increase in number of inflammatory odontogenic lesions, such as pericoronitis and paradental cysts, with increase in patients' age [Figure 2], possibly due to presence of semi-erupted teeth and consequently, biofilm accumulation. In our study, paradental cyst was more prevalent in female patients. This result is in accordance with that of de Souza et al. and in contrast to that of others studies,, possibly because the study population in the former was Brazilian, as was our study.
Access to results of radiographic examination was not possible in our study; instead, this information was provided by the surgeon. In future analysis, such data would be important to correlate with histopathological aspects; moreover, use of molecular markers as immunohistochemistry, can be effective to elucidate etiopathogenesis to improve understanding of these lesions.
| Conclusions|| |
In summary, there is evident gap in knowledge of management of soft tissue surrounding the crowns of unerupted teeth, under absence of characteristic radiological findings, including proliferative potential and treatment approach. Finding of high percentage rate of lesions observed in our sample suggests that tissues surrounding the crowns of unerupted teeth are highly likely to develop into pathological forms including odontogenic lesions. Based on our findings, diseases of odontogenic origin are under-diagnosed; pathologies of odontogenic origin may be diagnosed early and managed adequately by combined clinical, radiographic, and microscopic information.
School of Dentistry of Universidade Federal do Rio Grande do Sul and the financial support of the Coordination and Improvement of Higher Level or Education Personnel (CAPES). The authors wish to specially acknowledge Dr. Manoel Sant'Ana Filho for her contribution in histopathological diagnostics.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Pantelis Varvaki Rados
Faculdade de Odontologia, Universidade Federal Do Rio Grande Do Sul., R. Ramiro Barcelos, 2492 Porto Alegre, RS
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]