Structure Study of Amalgam III. The Marginal Structure of Class II Amalgam Fillings

Oral leukoplakias, particularly non-homogenous types, are often invaded by yeasts, with Candida albicans being the dominant species. The more advanced precancerous leukoplakia lesions yield more rarely occurring biotypes of C. albicans, suggesting a causal role for these biotypes in the malignant transformation. N-nitroso-benzylmethylamine (NBMA) is a compound able to induce carcinoma of the esophagus and the oral cavity in the rat. The catalytic potential of yeasts, isolated from leukoplakia lesions and from normal mucosa, to produce NBMA from the precursors N-benzyl-methylamine and nitrite was assessed at pH 6.8. The yeast strains differed in nitrosation potential, ranking from 0 to 1.2 μg NBMA/10⁶ cells. C. albicans strains of the more rarely occurring biotypes showed the highest nitrosation potential, whereas C. tropicalis, C. parapsilosis, and Torulopsis glabrata were ranked lower. Strains with high nitrosation potential were generally isolated from lesions with more advanced precancerous changes. Thus, further evidence is provided supporting the hypothesis that yeasts play a causal role in oral cancer by means of endogenous nitrosamine production.     

Yeast species and biotypes associated with oral leukoplakia and lichen planus

Of 36 patients, 17 had oral leukoplakia, including homogeneous and nonhomogeneous types, and 19 had reticular lesions of oral lichen planus. A sample of yeast flora in each patient was taken from the pathologic lesion as well as from normal-appearing mucosa. The isolated yeasts were identified according to species level, and identification was extended beyond the species level for one species, Candida albicans, to reveal the biotype by means of the Odds and Abbott procedure comprising tests for acid and salt tolerance, proteinase production, resistance to 5-fluorocytosine and safranine, and assimilation of urea, sorbose, and citrate. Yeasts were present in the lesions of 82% of leukoplakia patients, compared to 37% of lichen planus patients, a frequency of yeasts corresponding to that in healthy adults. C. albicans was the dominating species in lesions of both diseases, constituting 82% of all yeasts in the leukoplakia lesions. In addition, the following species were identified: Candida tropicalis, Candida pintolopesii, Torulopsis glabrata, and Saccharomyces cerevisiae. Eighteen biotypes of C. albicans were encountered, the most frequently occurring biotypes being 355 and 177. Differences between C. albicans biotypes isolated from pathologic and normal mucosa were encountered in five of eleven leukoplakia patients and in one of three lichen planus patients. This indicates that the oral cavity comprises several ecologic niches for yeasts. As nonhomogeneous leukoplakias are more likely to develop into carcinoma than are homogeneous leukoplakias, it is interesting to note that the C. albicans biotypes isolated from nodular lesions (one type of nonhomogeneous leukoplakia)--biotypes 145, 175, and 575--rarely occur.(ABSTRACT TRUNCATED AT 250 WORDS)     

Biotypes of oral Candida albicans isolates in human immunodeficiency virus-infected patients from diverse geographic locations

Oral Candida albicans isolates from HIV-infected individuals in Hong Kong, Australia, Germany and England were characterised using a biotyping system based on enzyme profiles, carbohydrate assimilation patterns and boric acid resistance of the yeasts. A total of 44 biotypes were found amongst the 117 oral C. albicans isolates examined. The major biotype AIR accounted for 17.9% of all isolates while the second commonest biotype was A1S (11.1% of isolates). Whereas these two biotypes were isolated from all the regions studied, there were a number of other biotypes unique to individual countries. The data indicate that there are many different sub-strains of oral C. albicans in HIV-infected patients, some of which are globally prevalent. However, further work is required to ascertain the diversity of oral C. albicans biotypes, if any, in health and disease.     

Identification of Candida albicans types related to healthy and pathological oral mucosa

This study comprised 100 healthy dentate adults and 53 patients with either chronic crythematous oral candidosis or oral leukoplakic lesions. The presence of yeasts was determined by microscopical examination of PAS–stained smears and by culture. Biopsy material was obtained from all lesions. The isolated yeasts were identified to species level. Strain phenotypes of 147 Candida albicans isolates were determined on the basis of the O dds & A bbott procedure (25, 26). Yeasts were found in the mouth of healthy dentate individuals both by culture and by smears. The identification of hyphae in healthy mucosa indicates that the presence of these structures is not an unequivocal sign of candidal infection. The results support the view that tobacco smoking may be a predisposing factor for candidal infection. Also, the results have shown an association between the occurrence of yeasts and the type of leukoplakic lesions. Finally, the strain differentiation has indicated an oral mycoflora in patients with candidal lesions disappearing after antimycotic treatment which was more homogeneous in composition than in patients with irreversible lesions; furthermore, certain strains may possess properties which may be important in the development of pathological conditions and premalignant changes.     

Oral lesions in children born to HIV–1 positive women

A cohort of 69 children born to HIV-1 positive women was studied to evaluate types, prevalences and relationships to clinical stages of HIV-1-related oral lesions. In addition, relationships among C. albicans biotypes, clinical features of oral candidiasis and HIV-1 disease were investigated. C. albicans biotypes did not correlate with clinical features of oral lesions, disease stages and CD4⁺ lymphocyte count. Of 8 patients with recurrent oral candidiasis. 4 changed clinical features and 5 changed biotype. Our study pointed out the high frequency (28.9%) of oral lesions, especially caused by fungi and the importance of the examination of the oral cavity in children born to HIV-1 positive women.     

Candida albicans in leukokeratotic lesions of oral mucosa

The potential presence of Candida albicans in oral leukokeratotic lesions, also entailing the need of additional antimiotic therapy, has been quite extensively discussed in literature. Therefore, the aim of this study was to assess the prevalence of Candida albicans isolates in subjects with oral leukoplakia as well as of candidal leukoplakia according to oral mucosa regions. The study included 60 subjects, mean age 46 years. A study group had 28 subjects with oral leukoplakia, whereas a control group comprised subjects free of any pathological alterations of oral mucosa. In all subjects, a clinical oral examination was performed and material for microbiological analysis taken. Following cultivation and incubation, tests of identification and microbiological analysis were carried out on the material thus grown. Results of the study revealed that Candida albicans was present in 67.9% of subjects with oral leukoplakia, which is the highest percentage reported on so far, and in 28.1% of subjects without any pathologic alterations of oral mucosa. The prevalence of candidal leukoplakia was found to be highest in oral mucosa, followed by lips, tongue and sublingual mucosa. Thus, these findings appear to clearly confirm the need of additional use of antimicotics, along with antikeratotic therapy of leukoplakia.     

Sj?gren's syndrome sufferers have increased oral yeast levels despite regular dental care.

AIM: To investigate the prevalence and quantity of oral yeasts and their association with oral candidiasis in Sj?gren's syndrome (SS) patients receiving regular dental care. MATERIALS AND METHODS: Yeasts in oral rinse and full-mouth supra-gingival plaque samples from 25 primary SS, 27 secondary SS and 29 control subjects were selectively cultured. All yeasts except single-species isolates were genotyped using pulsed field gel electrophoresis (PFGE). RESULTS: Ten (19%) SS sufferers had symptomless candidiasis. SS subjects had a higher prevalence (73%vs 7%) and quantity of yeasts than controls in both oral rinse and plaque samples (P < 0.05). The prevalence of yeasts in plaque was associated with candidiasis regardless of denture wearing (P < or = 0.04). Candida albicans was the predominant yeast isolated. PFGE showed 20 (66% of total) C. albicans isolate pairs, i.e. C. albicans species isolated from plaque and oral rinse samples of the same individual, were of closely related genetic clonal types (P < 0.01). CONCLUSIONS: Despite effective oral hygiene, more SS subjects than controls had detectable levels of oral yeasts and their presence in supra-gingival plaque was associated with candidiasis. Candida albicans colonized supra-gingival biofilm even in well-maintained SS individuals, posing a challenge to the control of oral candidiasis.     

Candida biotypes in human adult periodontitis

Fifty-five Candida isolates from human periodontal pockets were biotyped using the API 20C micromethod kit system. Candida albicans (11 biotypes) constituted 81.8% of all yeast isolates. A single biotype accounted for 57.8% of the subgingival C. albicans strains. The biotype distribution of C. albicans in human periodontal pockets appears to follow a selectivity pattern similar to that of other oral surfaces.     

Age-related acquisition of oral and nasopharyngeal yeast species and stability of colonization in young children

The occurrence and stability of colonization of oral yeast species and strains was determined from 40 healthy children during a 22-month follow-up at the ages 2, 6, 12, 18 and 24 months. In addition, salivary samples were obtained from the mothers at baseline (2 months) to study the role of the mother as the source of yeasts for the child. Yeasts were recovered at least once from 17/40 (43%) children by the age of 2 years. Of the 40 children, 11 (28%) were yeast-positive at multiple sampling occasions. No significant differences were found in recovery frequency of yeasts at different ages. Candida parapsilosis was isolated in 18/33 (55%) yeast-positive samples, and it predominated (share of positive findings 76%) at ages 12 to 24 months. The same yeast species was rarely detected in successive follow-up samples and thus on species level yeasts were transient colonizers in the developing oral flora of the children. Of the mothers 20/40 (50%) harbored yeasts. Candida albicans was recovered from 19/20 (95%) of the yeast-positive mothers and C. parapsilosis from none. Only 7/20 (35%) of the mothers with a yeast-positive finding had a yeast-positive child. In 5/7 (71%) of these mother-child pairs, both harbored the same yeast species (C. albicans) and in 3/5 (60%) of the pairs the AP-PCR profiles of the yeast isolates were identical suggesting possible transmission. In children, significant relationships (Fisher's exact-test, P < 0.05) were found between recovery of yeasts and use of pacifier at age over 12 months, eruption of first teeth at age over 6 months, mother cooling the child's food by blowing and mother cleaning the child's pacifier in her own mouth. In mothers, a significant relationship existed between recovery of yeasts and use of antibiotics.     

Oral precancerous disorders associated with areca quid chewing, smoking, and alcohol drinking in southern Taiwan

OBJECTIVE: To investigate the prevalence and the associated risk factors of oral precancerous disorders in southern Taiwan. METHODS: We conducted a cross-sectional community survey interviewing 1075 adult subjects, 15 years of age and over, gathered from randomly selected 591 households, and spanning five villages in southern Taiwan. The study protocol included a visual oral soft tissue examination and a questionnaire-based interview. The chi-square test was used to test the differences in prevalence of oral precancerous lesions and conditions by different "life styles" relating to current risk habits of current areca quid chewing, smoking, and alcohol drinking. To control for possible confounding, a logistic regression model was used to estimate the Odds Ratios (OR) for leukoplakia and oral submucous fibrosis (OSF). RESULTS: 136 precancerous lesions and conditions were detected among 1075 subjects (12.7%). The analysis of the spectrum of oral precancerous disorders detected, leukoplakia (n = 80), OSF (n = 17) and verrucous lesions (n = 9), demonstrated an association with gender (P < 0.001). There were statistically significant associations among leukoplakia (P < 0.01), OSF (P < 0.0001), and verrucous lesions (P < 0.0001) and the life style of current areca quid chewing, smoking, and alcohol drinking. The synergistic effect of smoking and areca quid chewing habit on leukoplakia and OSF was demonstrated. CONCLUSION: This study reinforces the association of current areca quid chewing without tobacco, cigarette smoking, and alcohol drinking to leukoplakia, OSF, and verrucous lesions in Taiwan.     

Sjögren's syndrome sufferers have increased oral yeast levels despite regular dental care

Aim:  To investigate the prevalence and quantity of oral yeasts and their association with oral candidiasis in Sjögren's syndrome (SS) patients receiving regular dental care.
Materials and methods:  Yeasts in oral rinse and full-mouth supra-gingival plaque samples from 25 primary SS, 27 secondary SS and 29 control subjects were selectively cultured. All yeasts except single-species isolates were genotyped using pulsed field gel electrophoresis (PFGE).
Results:  Ten (19%) SS sufferers had symptomless candidiasis. SS subjects had a higher prevalence (73% vs 7%) and quantity of yeasts than controls in both oral rinse and plaque samples ( P  < 0.05). The prevalence of yeasts in plaque was associated with candidiasis regardless of denture wearing ( P  ≤ 0.04). Candida albicans was the predominant yeast isolated. PFGE showed 20 (66% of total) C. albicans isolate pairs, i.e. C. albicans species isolated from plaque and oral rinse samples of the same individual, were of closely related genetic clonal types ( P  < 0.01).
Conclusions:  Despite effective oral hygiene, more SS subjects than controls had detectable levels of oral yeasts and their presence in supra-gingival plaque was associated with candidiasis. Candida albicans colonized supra-gingival biofilm even in well-maintained SS individuals, posing a challenge to the control of oral candidiasis.     

The prevalence of oral leukoplakia in 138 patients with oral squamous cell carcinoma

OBJECTIVES: To determine the relationship between oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC), and to evaluate possible differences between those carcinomas with and without associated leukoplakia. MATERIAL AND METHODS: A total of 138 patients were studied at the Stomatology Service of the University General Hospital, Valencia, Spain. These patients were divided into two groups: group 1, patients with oral cancer and leukoplakia, and group 2, patients with OSCC but with no associated premalignant lesions. The relationship between this precancerous lesion and the OSCC was evaluated, as well as the possible clinical and histological differences between the tumours of the two groups. RESULTS: Leukoplakia was detected in 27 (19.56%) patients with OSCC. No differences were found between the two groups regarding age and tumour location. However, statistically significant differences were observed with respect to the form, tumour stage and the presence of adenopathies in the cancers with and without leukoplakia; in that the tumours associated with leukoplakia were diagnosed as being at a more initial stage. CONCLUSIONS: Those patients with OL associated with oral cancer presented with tumours at a less advanced stage than those where no associated leukoplakia existed.     

Mixed Candida albicans and Candida glabrata populations associated with the pathogenesis of denture stomatitis

Introduction:  Oral yeasts are an important component of the resident microbial ecology of the oral cavity, but they are also associated with various forms of oral candidosis, such as denture stomatitis. Although Candida albicans is the predominant oral fungal pathogen, other species may also play an integral role in pathogenesis. The aim of this study was to examine the mycological ecology in patients with denture stomatitis, using an improved sampling technique, to determine whether species diversity and species quantity were related to oral pathology.
Methods:  Thirty-seven patients attending the Glasgow Dental Hospital were enrolled in this study following informed consent. A full clinical history was obtained, including details of their oral hygiene practices and the levels of erythema based on Newton's classification scale. Oral rinse, denture sonicate, and swab samples were taken, which were processed for quantitative and qualitative analysis of oral yeasts.
Results:  The proportion of patients with no inflammation or Newton's Types I, II, and III were 31, 33, 25, and 14%, respectively. Denture sonication was a superior sampling procedure, with statistically greater quantities of yeasts isolated using this methodology ( P  < 0.01). The predominant oral yeasts isolated were C. albicans (75%) and Candida glabrata (30%), which were isolated in higher proportions in patients with the highest grades of inflammation (100 and 80%), and in combination from 80% of these patients.
Conclusions:  This study has demonstrated that mixed C. albicans and C. glabrata biofilms may play an important role in the pathogenesis associated with severe inflammation in denture wearers.     

口腔白色念珠菌的PCR ITS1-ITS2基因分型法的建立及应用

目的：建立口腔白色念珠菌的PCRITS1-ITS2基因分型方法，并探讨其型别在口腔黏膜病中的流行病学意义。方法：提取21株临床菌株的DNA，PCR扩增ITS1-ITS2区域，并依据该区域核苷酸序列的差异进行基因分型。结果：用PCRITS1-ITS2方法将21株白念分为13型。结论：PCRITS1-ITS2基因分型法可作为一种有用的流行病学调查的工具以预防和监测口腔白念感染。     

Oral epithelium-Candida glabrata interactions in vitro

BACKGROUND: Oropharyngeal candidiasis is a common opportunistic infection and Candida glabrata is the second or third most frequently isolated species from oropharyngeal candidiasis lesions, after Candida albicans. The aim of this study was to study the cytokine-inducing and cell-damaging potential of C. glabrata in oral epithelial cells and compare this to C. albicans. METHODS: Oral epithelial cell lines and primary gingival epithelial cells were cocultured with C. glabrata strains GDH2269 and 94-11 or C. albicans strains SC5314 and ATCC28366. Supernatants were analysed for the presence of interleukin-1alpha (IL-1alpha), IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) by enzyme-linked immunosorbent assay. The cytotoxity of different strains was determined using the CytoTox-96 assay. RESULTS: Compared to C. albicans, C. glabrata induced different proinflammatory cytokine responses in oral epithelial cells; a high level of GM-CSF induction was only detected in C. glabrata-infected cells and not in C. albicans-infected cells, regardless of the origin of these cells (cell lines or primary cells) or the strain used. Like C. albicans, C. glabrata induced an IL-1alpha response by oral epithelial cells, but this response was both strain-dependent and epithelial cell origin-dependent. Unlike C. albicans, C. glabrata failed to induce a strong IL-8 response in any of the cell systems studied. Finally, in these studies C. glabrata showed lower cytotoxicity than C. albicans. CONCLUSIONS: C. glabrata is less cytotoxic than C. albicans and induces different proinflammatory cytokine responses in oral epithelial cells.     

小鼠对口腔念珠菌感染的体液免疫应答

目的建立敏感株和阻抗株小鼠口腔念珠菌感染模型，揭示两种小鼠对口腔念珠菌感染的体液免疫反应。方法雌性BALB／c和CBA／CaH小鼠及白色念珠菌3630用于本研究。1×10^8念珠菌／20μl接种于小鼠的口腔黏膜，建立口腔念珠菌感染模型；SDS—PAGE和Western—Blotting用于检测血清抗体。结果念珠菌敏感株鼠CBA／CaH的口腔感染比阻抗株鼠BALB／c严重（P〈0．05）；CBA／CaH小鼠在口腔免疫后5周产生了IgG1、IgG2a、IgM，而BALB／c小鼠仅产生IgG1。结论念珠菌敏感鼠CBA／CaH的口腔念珠菌感染比念珠菌阻抗鼠BALB／c感染更为严重；抗白色念珠菌抗体IgM可能对宿主的口腔念珠菌感染起保护作用。     

口腔鳞癌和癌前病变中端粒酶活性的检测

目的 探讨端粒酶活化在口腔粘膜鳞癌、癌前病变中的表达状况以及癌变过程中的作用。方法 采用端粒酶（ｔｅｌｏｍｅｒａｓｅ）聚合酶链反应（ｐｏｌｙｍｅｒａｓｅ ｃｈａｉｎ ｒｅａｃｔｉｏｎ,ＰＣＲ）、酶联免疫吸附法和端粒重复放大（ｔｅｌｏｍｅｒｅ ｒｅｐｅａｔ ａｍｐｌｉｆｉｃａｔｉｏｎ ｐｒｏｔｏｃｏｌ,ＴＲＡＰ）电泳法对２０例口腔粘膜鳞癌、１０例口腔粘膜白斑、２０例口腔粘膜扁平苔藓和１０例正常口腔粘     

光动力治疗口腔黏膜癌及癌前病变的临床进展

口腔癌是发生在口腔的恶性肿瘤之总称,严重影响人类生命和生活,发病率高,致残率和病死率高.许多口腔癌由癌前病变发展而来,最常见的是口腔黏膜白斑、扁平苔藓等.目前针对口腔癌一线治疗方案分为:手术切除、放射线治疗、化学治疗以及联合治疗.特别是高龄口腔癌症患者,传统治疗尚有一定的局限性和毒副作用.针对癌前病变常用药物和手术治疗...     

MAGE-A antigens in lesions of the oral mucosa

Oral squamous cell carcinoma develops continuously out of predamaged oral mucosa. For the physician and pathologist, difficulties arise in distinguishing precancerous from cancerous lesions. MAGE-A antigens are tumor antigens that are found solely in malignant transformed cells. These antigens might be useful in distinguishing precancerous from cancerous lesions. The aim of this study was to verify this assumption by comparing MAGE-A expression in benign, precancerous, and cancerous lesions of the oral mucosa. Retrospectively, biopsies of different oral lesions were randomly selected. The lesions that were included are 64 benign oral lesions (25 traumatic lesions (oral ulcers), 13 dental follicles, and 26 epulis), 26 oral lichen planus, 123 epithelial precursor lesions (32 epithelial hyperplasia found in leukoplakias, 24 epithelial dysplasia found in leukoplakias, 26 erythroplasia with oral epithelial dysplasia, and 41 carcinomas in situ in erythroleukoplakias). The lesions were immunohistochemically stained with the poly-MAGE-A antibody 57B, and the results were compared. Biopsies of oral lichen planus, oral ulcers, dental follicles, epulis, and leukoplakia without dysplasia showed no positive staining for MAGE-A antigens. Leukoplakia with dysplasia, dysplasia, and carcinomata in situ displayed positive staining in 33%, 65%, and 56% of the cases, respectively. MAGE-A antigens were not detectable via immunohistochemistry in benign lesions of the oral mucosa. The staining rate of dysplastic precancerous lesions or malignant lesions ranged from 33% to 65%. The MAGE-A antigens might facilitate better differentiation between precancerous and cancerous lesions of the oral mucosa.     

Prevalence of oral leukoplakia in Havana City, Cuba

Abstract A survey related to the detection of precancerous lesions of the oral cavity has been done in Cuba for the first time. The sample comprised 749 randomly selected workers from Havana City Province, taking into account the censal records of the Cuban population up to 1979. Prevalence of lesions and their relation to age, sex and predisposing factors, such as smoking, alcohol habits and mechanical trauma were studied. 4.4% of leukoplakia and preleukoplakia considered together and 2.1 % leukoplakia alone, and two cases of oral lichen planus and leukokeratosis nicotina palati (0.1 % of each) were found. The former lesions were more frequently encountered in people above 50 years old, specially in males and specifically among those who had smoked for more than 10 years. Sites of location most frequently encountered were the buccal mucosa and the labial commissures.