Antimicrobial Activity in Chitosan-Treated Prosthetic Materials: A Systematic Review

OBJECTIVE

The antimicrobial effect of prosthetic materials treated with chitosan was systematically reviewed.

METHODS

The searches were carried out on PubMed/Medline, Scopus, ISI Web of Science, LILACS, Embase, and Open Grey with searches performed in March 2022. Selection of in vitro studies, data extraction and risk of bias analysis were performed following the PRISMA guidelines and registered at the Open Science Framework. The evaluated prosthetic materials corresponded to PMMA and tissue conditioner, treated with chitosan.

RESULTS

After evaluating the eligibility criteria, 11 articles were included for the qualitative synthesis. The evaluated prosthetic materials corresponded to PMMA (n=8) and tissue conditioner (n=3). All studies performed the incorporation of chitosan in the tissue conditioner (n=3). Regarding PMMA, the use of chitosan as a denture cleanser was the most used (n=3), followed by incorporation (n=2), multilayers coating onto PMMA (n=2) and denture adhesive for PMMA (n=1). Chitosan has antimicrobial activity and is effective in the treatment of prosthetic materials in most studies, but it depends on some factors, such as the treatment method, the type and characteristics of the chitosan, the microorganism evaluated, and its form of organization.

CONCLUSION

Chitosan showed highly antimicrobial activity and was effective when used in prosthetic materials.

Idiopathic gingival fibromatosis: description of two cases

Gingival fibromatosis is an enlargement localized or generalized of the gingival tissue characterized by an expansion and accumulation of the connective tissue, predominantly type I collagen, with occasional presence of increased number of cells, supposed fibroblastic proliferation. Gingival fibromatosis can be induced as a side effect of systemic drugs, such as phenytoin, cyclosporin, and nifedipine, or due to hereditary factors. However, in some cases, the gingival overgrowth is idiopathic. This paper reports two cases of idiopathic gingival fibromatosis and discusses the diagnosis, histopathological features, treatment and immunohistochemical evaluation of myofibroblasts of this condition. The tissues removed were fixed in formalin, and sections used for hematoxylin and eosin and Masson tricromic stain. To determine the presence of myofibroblasts, we performed immunohistochemistry against a-SMA protein. Histological examination revealed epithelial hyperplasia with long rete pegs and increase in the dense fibrous connective tissue. The Masson tricromic stain revealed wide bundles of collagen strongly stained. It was showed negative labeling to a-SMA. These results strongly suggest that myofibroblasts are not involved in gingival overgrowth in the cases of IGF reported. Future studies will be necessary to determine the pathogenesis of idiopathic gingival fibromatosis.

Effectiveness of computed tomography to evaluate central giant cell lesion

Central giant cell lesion (CGCL) is a benign disease involving the mandible (70%) more than the maxilla; it tends to be more common in women. Clinically, the lesion may be associated with pain, tooth displacement, facial asymmetry, paraesthesia and ulceration of the mucosa. The radiographic aspect of CGCL is highly variable since it may appear as a unilocular or multilocular radiolucent area with expansion and perforation of the cortical bone. Few previous reports have dealt with the usefulness of CT in the evaluation of this lesion. The purpose of this study is to report the clinical and imaging features of a case, including CT, treated by a conservative method.

Characterization of inflammatory cells in oral paracoccidioidomycosis

Paracoccidioidomycosis (Pmycosis) is one of the most common deep mycoses in many regions of Latin America, particularly in Brazil. Microscopically, it shows granulomatous inflammatory reaction with giant cells, macrophages, lymphocytes, plasma cells, polymorphonuclear neutrophilic leukocytes, and eosinophils. The purpose of this study was to assess the distribution of inflammatory cells in oral Pmycosis. Fifteen cases of oral Pmycosis were studied by immunohistochemistry for the presence of macrophages, CD4(+) and CD8(+) lymphocytes, CD20(+), CD15(+), and S100(+) cells. Macrophages were the main cells in well-organized granulomas and non-granulomatous areas. The CD4 phenotype was predominant in well-organized granulomas and a balance between CD4(+) and CD8(+) cells was observed in non-granulomatous areas. Dendritic, S100(+) cells were found mainly in the epithelium, in subepithelial connective tissue, and at the periphery of organized granulomas. CD15(+) cells were concentrated mainly in areas of intraepithelial microabscess and ulceration. Macrophages and T cells are the predominant cells in oral Pmycosis. Well-organized granulomas contain fewer yeast particles, indicating a more effective host immune response. Better understanding of the histopathological changes in oral Pmycosis might help determine treatment, severity and systemic involvement of the disease.

Histomorphometry and immunohistochemical features of grade I (WHO) oral radiomucositis

AIMS

The aims of this study were to describe the immunohistopathological and morphometric features of oral mucositis grade I (WHO).

MATERIAL AND METHODS

Ten samples of oral mucositis were biopsied and submitted to histopathological, morphometric and immunohistochemical analyses (CD68, Ki-67 and p53). The samples were compared with the buccal mucosa of head and neck cancer patients before radiotherapy (NMCP), normal buccal mucosa (NM) and oral dysplasia (OD).

RESULTS

Epithelial thickness, area and perimeter were decreased in oral mucositis and inflammatory components, increased when compared with NMCP. CD68 immunoreactivity, near to the epithelium, was more evident in oral mucositis than in NMCP (P = 0.01). The Ki-67 counts were higher in oral mucositis than in NM and NMCP (P = 0.001 and P = 0.043, respectively), but without any difference with OD (P = 0.284). The p53 staining was present in all cases of mucositis and oral dysplasia, but negative in NMCP and NM.

CONCLUSIONS

Oral mucositis grade I (WHO) presented epithelial atypia and atrophy, increased inflammatory response, with relevant Ki-67 count and positiveness for p53.

Cytokeratin expression in pseudoepitheliomatous hyperplasia of oral paracoccidioidomycosis

Paracoccidioidomycosis (Pmycosis) is one the most prevalent deep systemic mycoses in Latin America. It is characterized by granulomatous inflammation and pseudoepitheliomatous hyperplasia. Cytokeratins (CKs) are a group of intermediate filaments of epithelial cells and their expression varies according to the epithelium type, differentiation and pathological processes. This study describes cytokeratin expression as examined by immunohistochemistry, in 28 cases of oral Pmycosis involving the buccal mucosa, lip, gingiva and hard palate. Expression of CKs in the basal layer of the epithelium in pseudoepitheliomatous hyperplasia of Pmycosis was similar to that in normal oral mucosa (NOM), but in Pmycosis CK1 and CK10 were not expressed in the spinous and superficial layers of the lip, gingiva or hard palate, and, in the spinous and superficial layers of the lip and buccal mucosa, CK14 was positive in contrast to NOM where it was negative. In Pmycosis, CK6 was more frequently expressed in the spinous layer of the lip, gingiva and hard palate, but nevertheless CK16 expression was decreased in the spinous and superficial layers of the gingiva and hard palate. We conclude that pseudoepitheliomatous hyperplasia in oral Pmycosis shows a different pattern of CK expression, particularly CKs 1, 10 and 14, compared with NOM.

Cell proliferation and p53 expression in pseudoepitheliomatous hyperplasia of oral paracoccidioidomycosis

Paracoccidioidomycosis (PCMycosis) is a systemic mycosis frequently found in many regions of Latin America. Microscopically, it is characterised by granulomatous inflammation and pseudoepitheliomatous hyperplasia (PEH). This work describes the proliferation index and p53 expression by immunohistochemistry in PEH of PCMycosis, normal oral mucosa (NOM) and mild oral epithelial dysplasia (ED). Ki67 positive cells were present in the basal and parabasal layers in NOM and PEH, while in ED it was also observed in the spinous layer. Percentage of ki67 positive cells was 7.7, 28.2 and 46.0 in NOM, PEH and ED respectively. p53 was negative in NOM and in PEH it was expressed by few cells in the basal layer of only three cases. However, it was expressed in all cases of ED, in basal and parabasal layers. Although histologically PEH mimics well-differentiated squamous cell carcinoma, its proliferative pattern and p53 expression are more similar to NOM than to dysplasia. These findings, confirm PEH as a reactive process probably associated with the underlying chronic inflammation.

Denture stomatitis and salivary Candida in Brazilian edentulous patients

Denture stomatitis (DS) is frequently associated with high levels of Candida in saliva and deficient denture hygiene. In order to analyse the incidence of DS and its pre-disposing factors, we evaluated 77 edentulous patients before and 6 months after the placement of new complete dentures. Denture stomatitis was observed in 50.6 and 18.2% of the patients at the first and second evaluation, respectively. Salivary flow, Candida counts in saliva and Candida species were similar in both evaluations. Denture stomatitis and Candida in saliva were more common in females. Our results showed that denture replacement and denture hygiene improvement were useful for DS resolution, particularly types I and II. However, oral and denture hygiene must be continuous, inasmuch as salivary Candida counts remained high and it is considered an important pre-disposing factor for DS.