Does continuous chemical disinfection affect mechanical properties of CAD/CAM PMMA?

PURPOSE: This study was aimed at analyzing the effect of disinfectants on the roughness and mechanical properties of computer-aided design/computer-aided manufacturing (CAD/CAM) polymethylmethacrylate (PMMA) dentures. MATERIALS AND METHODS: Two groups of denture base resins were tested: heat-polymerized and milled blocks. The specimens were shaped (n=80) for flexural strength (FS), flexural modulus (FM), and (n=240) for the properties of roughness (Ra) and microhardness alterations (KHN). They were categorized into the following groups based on immersion: control (deionized water), H1 (1% sodium hypochlorite), H05 (0.5% sodium hypochlorite), and C2 (2% chlorhexidine) groups. The immersion periods were 0 (T0), 130 (T1), and 260 (T2) cycles. Statistical analyses were performed for flexural properties using the three-way analysis of variance (ANOVA). Microhardness and surface roughness were analyzed using repeatedmeasures ANOVA. A significance level of 5% was set. RESULTS: CAD/CAM PMMA showed higher FS (P = .001) and FM (P < .001) than conventional PMMA. The KHN value was superior to the conventional PMMA (P < .001). The chemical solution affected the surface roughness of both resins (P = .007). The CAD/CAM PMMA block showed increased Ra values when H1 was used. Cycling separately increased the FS of conventional PMMA (T1 vs. baseline; P < .05). However, the FM of CAD/CAM PMMA was higher (T1 and T2 vs. baseline; P < .05). The time factor increased the microhardness of both resins (T2 vs. baseline; P < .05). CONCLUSION: The CAD/CAM resin showed higher values compared to conventional PMMA in all tests, regardless of the chemical solution used; however, the values obtained for both resins were clinically acceptable. Int J Prosthodont 2023. doi: 10.11607/ijp.8301.

Mast cells exhibit intracellular microbicidal activity against Aggregatibacter actinomycetemcomitans.

BACKGROUND AND OBJECTIVE: Several studies have demonstrated that mast cells are equipped with versatile tools to combat and kill bacteria. Additionally, mast cells produce and secrete a variety of mediators, which either regulate the host's immune system or directly attack bacteria. In this study, the intracellular microbicidal capacity of mast cells against Aggregatibacter actinomycetemcomitans was evaluated. METHODS: Murine mast cells were challenged in vitro with A actinomycetemcomitans for 3, 5, 10, and 24 hours. Subsequently, the colony-forming units were counted. Additionally, the production and release of nitric oxide and hydrogen peroxide were analyzed by DAF-FM diacetate, the Griess reaction, and the Amplex Red kit, respectively. Cell death was evaluated using FITC Annexin V and propidium iodide staining. RESULTS: Mast cells are able to efficiently eliminate periodontopathogen, with best results after 10 hours of intracellular challenge. The production/release of nitric oxide-and to a lesser extent of hydrogen peroxide-by mast cells was in agreement with its microbicidal capacity. Ninety percent of the mast cells  maintained their cellular viability even after 24 hours of bacterial challenge. CONCLUSIONS: This is-to the best of our knowledge-the first report to describe the intracellular microbicidal activity of mast cells against A actinomycetemcomitans, concerning the production and release of potentially bactericidal substances. Further, the low number of cell deaths confirms that the decreased number of colony-forming units was due to the higher antimicrobial activity of mast cells. The results highlight the importance of these cells in the defense mechanisms of biofilm-induced periodontal disease.

Rhizopus-host interplay of disseminated mucormycosis in immunocompetent mice.

Aim: To investigate the immune response of disseminated Ryzopus oryzae infection in immunocompetent mice. Methods: C57Bl/6, BALB/c and Swiss wild-type mice were intravenously infected with R. oryzae; the parameters of infection and immune response were determined. Transcriptional signature of Th17 immune response and infection in Il17ra-/- mice were also evaluated. Results: All mouse strains showed an initial spread of R. oryzae in the target tissues; however, after 30 days, C57Bl/6 and BALB/c mice showed an effective fungal clearance associated with specific production of IL-17 and IL-2. We also observed that 60% of Il17ra-/- mice succumbed to infection within 16 days. Conclusion: This study has established an immunocompetent model for disseminated mucormycosis and highlighted the role of IL-17 signaling in immunity against R. oryzae.

Rhizopus-host interplay of disseminated mucormycosis in immunocompetent mice

Aim: To investigate the immune response of disseminated Ryzopus oryzae infection in immunocompetent mice. Methods: C57Bl/6, BALB/c and Swiss wild-type mice were intravenously infected with R. oryzae; the parameters of infection and immune response were determined. Transcriptional signature of Th17 immune response and infection in Il17ra-/- mice were also evaluated. Results: All mouse strains showed an initial spread of R. oryzae in the target tissues; however, after 30 days, C57Bl/6 and BALB/c mice showed an effective fungal clearance associated with specific production of IL-17 and IL-2. We also observed that 60% of Il17ra-/- mice succumbed to infection within 16 days. Conclusion: This study has established an immunocompetent model for disseminated mucormycosis and highlighted the role of IL-17 signaling in immunity against R. oryzae(AU).

CD44 and ALDH1 immunoexpression as prognostic indicators of invasion and metastasis in oral squamous cell carcinoma.

BACKGROUND: Tumour metastasis has been associated with cancer stem cells, a small population with stem-like cells properties, higher rate of migration and metastatic potential compared to cells from the tumour bulk. Our aim was to evaluate the immunoexpression of the putative cancer stem cell biomarkers ALDH1 and CD44 in primary tumour and corresponding metastatic lymph nodes. METHODS: Tumour tissue specimens (n = 50) and corresponding metastatic lymph nodes (n = 25) were surgically obtained from 50 patients with oral squamous cell carcinoma and submitted to immunohistochemistry. CD44 and ALDH1 were semi-quantitatively scored according to the proportion and intensity of positive cells within the invasive front and metastatic lymph nodes as a whole. A combined score was obtained by multiplying both parameters and later dichotomized into a final score classified as low (≤2) or high (>2) immunoexpression. RESULTS: ALDH1 immunoexpression and CD44 immunoexpression were detected in both tumour sites, although the means of ALDH1 (P = .0985) and CD44 (P = .4220) cells were higher in metastasis compared to primary tumours. ALDH1high was positively associated (P = .0184) with angiolymphatic invasion, while CD44high was positively associated (P = .0181) with metastasis (N+). At multivariate analysis, CD44 significantly increased the odds of lymph node metastasis, regardless of T stage (OR = 8.24; 1.64-65.64, P = .0088). CONCLUSIONS: CD44 immunoexpression was a significant predictor of lymph node metastasis, while ALDH1high immunostaining was associated with angiolymphatic invasion. Altogether, it suggests that immunoexpression of CD44 and ALDH1 links the cancer stem cell phenotype with oral squamous cell carcinoma invasion and metastasis.

TLR2-/- Mice Display Increased Clearance of Dermatophyte Trichophyton mentagrophytes in the Setting of Hyperglycemia.

Dermatophytosis is one of the most common human infections affecting both immunocompetent individuals and immunocompromised patients, in whom the disease is more aggressive and can reach deep tissues. Over the last decades, cases of deep dermatophytosis have increased and the dermatophyte-host interplay remains poorly investigated. Pattern recognition molecules, such as Toll-like receptors (TLR), play a crucial role against infectious diseases. However, there has been very little research reported on dermatophytosis. In the present study, we investigated the role of TLR2 during the development of experimental deep dermatophytosis in normal mice and mice with alloxan-induced diabetes mellitus, an experimental model of diabetes that exhibits a delay in the clearance of the dermatophyte, Trichophyton mentagrophytes (Tm). Our results demonstrated that inoculation of Tm into the footpads of normal mice increases the expression of TLR2 in CD115+Ly6Chigh blood monocytes and, in hypoinsulinemic-hyperglycemic (HH) mice infected with Tm, the increased expression of TLR2 was exacerbated. To understand the role of TLR2 during the development of murine experimental deep dermatophytosis, we employed TLR2 knockout mice. Tm-infected TLR2-/- and TLR2+/+ wild-type mice exhibited similar control of deep dermatophytic infection and macrophage activity; however, TLR2-/- mice showed a noteworthy increase in production of IFN-γ, IL-10, and IL-17, and an increased percentage of splenic CD25+Foxp3+ Treg cells. Interestingly, TLR2-/- HH-Tm mice exhibited a lower fungal load and superior organization of tissue inflammatory responses, with high levels of production of hydrogen peroxide by macrophages, alongside low TNF-α and IL-10; high production of IL-10 by spleen cells; and increased expansion of Tregs. In conclusion, we demonstrate that TLR2 diminishes the development of adaptive immune responses during experimental deep dermatophytosis and, in a diabetic scenario, acts to intensify a non-protective inflammatory response.

Effect of denture-coating composite on Candida albicans biofilm and surface degradation after disinfection protocol.

INTRODUCTION: Denture stomatitis is the most common pathology affecting denture wearers and its main cause is colonisation of dentures with Candida albicans. OBJECTIVE: This study investigated the effectiveness of two commercial composite surface sealants (Biscover(®) LV and Surface Coat(®)) to reduce C. albicans biofilm colonisation on denture resin, as well as their surface integrity after disinfection cycles with 1% sodium hypochlorite solution. METHODS: Heat-cured acrylic resin specimens were manufactured (10 mm × 10 mm × 1 mm). The specimen surfaces were mechanically polished to simulate rough or smooth denture surfaces. Four surface-treatment groups were tested: smooth surfaces [0.3 µm of mean roughness (Ra)]; rough surfaces (3 µm of Ra); rough surfaces treated with Biscover(®) LV; and rough surfaces treated with Surface Coat(®). Specimens of each group were randomly divided to undergo immersion in distilled water or 1% sodium hypochlorite for 30 or 90 cycles each. Specimens of all groups in each immersion solution were tested using a crystal violet (CV) staining assay for biofilm quantification and by scanning electron microscopy for visual analyses of surface integrity and biofilm structure. CV assay data were analysed using one-way analysis of variance (ANOVA) followed by Tukey's multiple comparison test (P < 0.05). RESULTS: The effectiveness and surface integrity of Biscover(®) LV-treated surfaces were similar to those of smooth surfaces, whereas Surface Coat(®) -treated surfaces presented a similar performance to rough surfaces in all solutions and cycles. CONCLUSION: These results suggest the possibility of clinical use of Biscover(®) LV for denture coating on surfaces in which mechanical polish is not indicated, such as the fitting surface.

The Beneficial Effect of Equisetum giganteum L. against Candida Biofilm Formation: New Approaches to Denture Stomatitis.

Equisetum giganteum L. (E. giganteum), Equisetaceae, commonly called "giant horsetail," is an endemic plant of Central and South America and is used in traditional medicine as diuretic and hemostatic in urinary disorders and in inflammatory conditions among other applications. The chemical composition of the extract EtOH 70% of E. giganteum has shown a clear presence of phenolic compounds derived from caffeic and ferulic acids and flavonoid heterosides derived from quercitin and kaempferol, in addition to styrylpyrones. E. giganteum, mainly at the highest concentrations, showed antimicrobial activity against the relevant microorganisms tested: Escherichia coli, Staphylococcus aureus, and Candida albicans. It also demonstrated antiadherent activity on C. albicans biofilms in an experimental model that is similar to dentures. Moreover, all concentrations tested showed anti-inflammatory activity. The extract did not show cytotoxicity in contact with human cells. These properties might qualify E. giganteum extract to be a promising alternative for the topic treatment and prevention of oral candidiasis and denture stomatitis.

Papillary Cystadenoma of Minor Salivary Glands: Report of 11 Cases and Review of the English Literature.

Papillary cystadenoma is a rare, benign salivary gland tumor which is well-circumscribed, containing cystic cavities with intraluminal papillary projections. Only 19 cases arising within minor salivary glands (MnSG) from the oral cavity sites have been reported in the English literature (PubMed 1958-2014). We report 11 new cases of MnSG papillary cystadenomas in conjunction with a review of the literature. Demographic information, clinical and histologic features, treatment and prognosis are compiled and discussed for all 30 cases reported in the English literature.

Mast cells act as phagocytes against the periodontopathogen Aggregatibacter actinomycetemcomitans.

BACKGROUND: Evidence to date shows that mast cells play a critical role in immune defenses against infectious agents, but there have been no reports about involvement of these cells in eliminating periodontopathogens. In this study, the phagocytic ability of mast cells against Aggregatibacter actinomycetemcomitans compared with macrophages is evaluated. METHODS: In vitro phagocytic assays were conducted using murine mast cells and macrophages, incubated with A. actinomycetemcomitans, either opsonized or not, with different bacterial load ratios. After 1 hour, cells were stained with acridine orange and assessed by confocal laser-scanning electron microscopy. RESULTS: Phagocytic ability of murine mast cells against A. actinomycetemcomitans was confirmed. In addition, the percentage of mast cells with internalized bacteria was higher in the absence of opsonization than in the presence of opsonization. Both cell types showed significant phagocytic activity against A. actinomycetemcomitans. However, the percentage of mast cells with non-opsonized bacteria was higher than that of macrophages with opsonized bacteria in one of the ratios (1:10). CONCLUSIONS: This is the first report about the participation of murine mast cells as phagocytes against A. actinomycetemcomitans, mainly in the absence of opsonization with human serum. Our results may indicate that mast cells act as professional phagocytes in the pathogenesis of biofilm-associated periodontal disease.

Salivary immunity in elderly individuals presented with Candida-related denture stomatitis.

OBJECTIVES: Elderly individuals with Candida-related denture stomatitis (DS) present with a reduced defence against Candida albicans. This study evaluated levels of antimicrobial mediators in the elderly DS saliva and salivary neutrophils' activation characteristics compared with elderly and young without DS. METHODS: Salivary peroxidases (SPO) and elastase activities (ELA), nitric oxide (NO), transforming growth factor beta (TGF-ß), IL-6 and CCL3 production were determined in saliva from elderly with or without DS, and young control individuals. TLR4, CXCR1, CD11b, CD16 and CD32 expression on salivary neutrophils were evaluated. Correlations between number and apoptosis rate of salivary neutrophils, enzymatic activities and cytokine levels were determined. RESULTS: Elderly DS individuals exhibited the lowest SPO and ELA activities. Also, the activity of both enzymes was low in elderly without DS. Although both elderly groups showed higher salivary NO and TGF-ß levels compared to young control groups, elderly DS presented the highest salivary NO, TGF-ß, IL-6 and CCL3 levels. Decreased percentages of salivary TLR4(+) and CD16(+) neutrophils were detected in both elderly groups. Although these damages could influence the establishment and persistence of DS, the highest levels of salivary IL-6 and CCL3 in elderly DS could be preventing more serious complications.

Early diagnosis of Gorlin-Goltz syndrome: case report.

The Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome (NBCCS), is an infrequent multisystemic disease inherited in a dominant autosomal way, which shows a high level of penetrance and variable expressiveness. It is characterized by keratocystic odontogenic tumors (KCOT) in the jaw, multiple basal cell nevi carcinomas and skeletal abnormities. This syndrome may be diagnosed early by a dentist by routine radiographic exams in the first decade of life, since the KCOTs are usually one of the first manifestations of the syndrome. This article paper reports the case of a patient, a 10-year-old boy with NBCCS, emphasizing its clinical and radiographic manifestations. This study highlights the importance of health professionals in the early diagnosis of NBCCS and in a preventive multidisciplinary approach to provide a better prognosis for the patient.

Dendritic cells in immunosenescence: [review]

The term immunosenescence usually refers to the aging of the immune system. Aging isassociated with the progressive decline in immune function, resulting in an increasing susceptibility of the bodyto infection, taking into account the specific changes in T- cells, macrophages, neutrophils and dendritic cells.Dendritic cells (DCs) are play a key role in the induction of both innate and adaptive immunity. There areimmature and mature forms located in the non-lymphatic organs and lymph nodes, respectively. DCs initiateand regulate the highly pathogen-specific adaptive immune responses, and are central to the development ofimmunologic memory and tolerance. In this text, we will briefly review DCs and changes associated withhuman aging, such as cytokine secretion, antigen capture, migration and priming of T cells. This functionaldecline would lead to major morbidity associated with infections such as influenza and pneumonia, whichaffect mucosal surfaces; in addition the increased incidence of cancer in the elderly is associated with thepotential role of DCs.

Immunolocalization of matrix metalloproteinases-2 and -9 during apical periodontitis development.

OBJECTIVE: The objective of this study was to determine the expression of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) during apical periodontitis development. METHODS: Using an experimental design of induced periapical lesions in rats and immunohistochemistry assay as investigative tool, the MMP-2 and MMP-9 expression and distribution were evaluated at 3, 7, 14, 21, 30, 60 and 90 days after coronary access and pulp exposure of the first left mandibular molar to the oral environment. Two blind observers scored the immunoreactivity. A semi-quantitative analysis was performed. RESULTS: Except at day 3, MMP-2 and MMP-9 immunostaining was observed in all experimental periods. The MMP-2 (p=0.004) and MMP-9 (p=0.005) immunostaining was higher in the period between 7 and 21 days. They were mainly observed in cells surrounding the apical foramen and adjacent periapical areas. Cells into the hypercementosis areas were strongly stained while both osteoblasts and osteoclasts presented discrete staining along of this study. No staining was observed on epithelial walls. At 30, 60 and 90 days, the subjacent connective tissue presented intense MMP-2 and MMP-9 immunostaining in mononuclear cells (suggestive of fibroblasts, macrophages, infiltrating neutrophils and lymphocytes). CONCLUSION: The results observed in this study suggest that MMP-2 and MMP-9 play a critical role in the development of inflammatory periapical lesions, probably involved in the extracellular matrix (ECM) degradation during the initial phase of the lesion development.

Expression of bone resorption regulators (RANK, RANKL, and OPG) in odontogenic tumors.

OBJECTIVE: To investigate the expression of bone resorption regulators (receptor activator of nuclear factor kappa B [RANK], RANK ligand [RANKL], and osteoprotegerin [OPG]) in calcifying cystic odontogenic tumor (CCOT), adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), odontogenic myxoma (OM), and ameloblastic fibroma (AF). STUDY DESIGN: The expression of these mediators was evaluated by means of immunohistochemistry. RESULTS: All specimens demonstrated positive immunoreactivity to RANK, RANKL, and OPG. The quantification of these mediators in epithelium revealed a similar pattern of expression for RANKL and OPG in CCOT, AOT, CEOT, and AF. With regard to stromal/mesenchymal cells, the majority of AOT and CCOT cases showed a higher content of OPG than RANKL, whereas CEOT, OM, and especially AF had a tendency to present a greater content of RANKL than OPG. CONCLUSION: Our data indicate that the CCOT, AOT, CEOT, OM, and AF cell constituents express key regulators of bone metabolism that might locally modulate tumor-associated bone resorption.