Michael McCullough

The role of alcohol in oral carcinogenesis with particular reference to alcohol-containing mouthwashes

Worldwide, oral cancer represents approximately 5 per cent of all malignant lesions, with over 800 new intra-oral squamous cell carcinomas registered in Australia each year. Despite recent advances in therapy, the five-year survival rate remains around 50 per cent and the sequelae of treatment can be seriously debilitating. It has been long established that smoking and alcohol consumption are risk factors linked to the development of oral cancer. This review assesses the epidemiological evidence, supportive in vitro studies and mechanism by which alcohol is involved in the development of oral cancer. Further, we review the literature that associates alcohol-containing mouthwashes and oral cancer. On the basis of this review, we believe that there is now sufficient evidence to accept the proposition that alcohol-containing mouthwashes contribute to the increased risk of development of oral cancer and further feel that it is inadvisable for oral healthcare professionals to recommend the long-term use of alcohol-containing mouthwashes.

Candida albicans: a review of its history, taxonomy, epidemiology, virulence attributes, and methods of strain differentiation

The dimorphic yeast Candida albicans has been recognized as an increasingly important human pathogen particularly in immunocompromised hosts because of advanced age, infection or immunosuppressive therapy. This review outlines the history, taxonomy and epidemiology of this medically important yeast as well as discussing some of characteristics which are purported to be related to its virulence. Methods utilized for strain differentiation in the study of the epidemiologic relationship of members of this species are discussed.

Oral yeast carriage correlates with presence of oral epithelial dysplasia

Previous studies have suggested a link between the presence of Candida albicans and the development of oral squamous cell carcinoma (OSCC). The aim of the present study was to assess the presence and level of colonisation of oral yeast in patients undergoing an incisional oral mucosal biopsy in order to assess whether the amount of oral yeast present correlated with the presence and degree of oral epithelial dysplastic or neoplastic change. Two hundred and twenty-three patients who were undergoing an incisional biopsy for the diagnosis of an oral mucosal lesion were enrolled in this study. Mouth swills were obtained from each patient for the presence and amount of oral yeast present. Some of the patients (44.6%) had a histopathological diagnosis of either oral epithelial dysplasia (OED) or OSCC and the frequency of oral yeast carriage was significantly greater (P<0.001) in these patients than those without histopathologically detected dysplastic or neoplastic oral lesions. Furthermore, significantly (P<0.001) more patients with OED or OSCC had a higher number of yeast (over 1000 cfu/ml) in their oral cavity than patients without any evidence of epithelial dysplasia or neoplasia histopathologically. The degree of epithelial dysplasia present in these patients also correlated with higher amounts of yeast in the oral cavity (P=0.017). The results of the present study reveal that there is an interaction between oral carriage of yeast and oral epithelial dysplasia, however it remains unclear how yeast infection influences the development and progression of dysplasia.

Orofacial granulomatosis – a 20-year review

Orofacial granulomatosis (OFG) is the presence of persistent enlargement of the soft tissues of the oral and maxillofacial region, characterized by non-caseating granulomatous inflammation in the absence of diagnosable systemic Crohns disease (CD) or sarcoidosis. Over 20 years have passed since OFG was first described and an extensive review of the literature reveals that there is no consensus whether OFG is a distinct clinical disorder or an initial presentation of CD or sarcoidosis. Furthermore, the precise cause of OFG is still unknown although several theories have been suggested including infection, genetic predisposition and allergy. The clinical outcome of OFG patients continues to be unpredictable. Current therapies remain unsatisfactory. Regular clinical review is indicated to identify the development of gastrointestinal or systemic involvement. The aim of this review was to analyse the developments in our understanding of the aetiology, pathogenesis and treatment protocols, with particular emphasis on management and outcomes of OFG since this entity was first described in 1985.

Oral fungal infections: an update for the general practitioner

Oral candidosis is the most common fungal infection encountered in general dental practice. It manifests in a variety of clinical presentations which may mimic more sinister diseases, and can occasionally be refractory to treatment requiring the attention of an oral medicine specialist. Management of oral candidosis should always include a thorough investigation of underlying predisposing conditions, as the disease often presents when the patient is systemically compromised. This update highlights the pathogenesis, clinical presentation, and management strategies of oral Candidal lesions commonly encountered in dental practice.

Efficacy of tissue autofluorescence imaging (velscope) in the visualization of oral mucosal lesions

Technology that highlights potentially malignant oral lesions in a highly sensitive and specific manner will aid clinicians in early diagnosis of these conditions. This study assessed the efficacy of direct tissue autofluorescence imaging Visually Enhanced Lesion Scope (VELScope) in the detection of oral mucosal lesions.

Molecular Epidemiology of Blastomyces dermatitidis

The inhalation of conidia of Blastomyces dermatitidis, a fungus found in soil, causes disease in humans and animals. We studied the genetic diversity of this pathogen by extracting DNA yeasts and analyzing them with a polymerase chain reaction (PCR)-based typing system we developed, which used restriction fragment analysis of amplicons from the regions between the rDNA repeats and allowed us to class isolates into 3 major groups. Strains were further differentiated by use of PCR fingerprinting with 3 different primers. Fifty-nine isolates collected over 35 years from 15 regions (United States, India, Africa, Canada) were analyzed. Genotypic groups A, B, and C contained 17, 23, and 19 isolates, which were divided into 5, 15, and 12 types, respectively. All 16 isolates from North America in group A were from the upper midwestern United States or Canada, whereas 0 of 20 isolates from the southeastern United States were in group A. Studies of the largest collection from 1 locale (Eagle River, WI), revealed that the soil isolates studied were not responsible for the majority of cases in this outbreak, as previously proposed, and that >1 strain was present in the environment and in patients. Overall, these results provide a tool for the epidemiological study of blastomycosis and illuminate the genetic and geographic diversity of this important pathogen.

Genotype and phenotype of oral Candida albicans from patients infected with the human immunodeficiency virus.

Candida albicans has been shown to vary in its phenotypic expression with the progression of human immunodeficiency virus (HIV) infection. Isolates of C. albicans were obtained from 45 patients with HIV infection during the progression of their disease and differentiated using two methods. The first utilized the morphological characteristics of colonies, and the second method utilized a small portion of C. albicans DNA as a probe on Southern-transferred, EcoRI-digested C. albicans genomic DNA. In 67% of the patients a single strain of C. albicans, as determined by the DNA analysis, was isolated from each individual. The phenotypic expression of the genetically identical strains varied considerably over the experimental period with one morphotype being predominant. These results showed that the genotype of C. albicans persisted in the majority of HIV-infected individuals, but that the phenotypical expression of this strain changed. A novel finding in this study was that 18 strains of C. albicans had DNA which did not hybridize to the probe used.

Oral Human Papillomavirus in Men Having Sex with Men: Risk-Factors and Sampling

Background Human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma is becoming more common. We examined prevalence and risk factors for oral HPV among men who have sex with men (MSM) and compared sampling and transport methods. Methods In 2010, 500 MSM (249 HIV-positive) attending Melbourne Sexual Health Centre answered a questionnaire, swabbed their mouth and throat and collected a gargled oral rinse sample. Half the oral rinse was transported absorbed in a tampon (to enable postage). HPV was detected by polymerase chain reaction, and genotyped by Roche Linear Array®. Men with HPV 16 or 18 were retested after six months. Results Any HPV genotype was detected in 19% (95% confidence intervals (CI) 15–25%) of HIV-infected men and 7% (95% CI 4–11%) of HIV-negative men (p<0.001), and HPV 16 was detected in 4.4% (95% CI 2–8%) of HIV-infected men and 0.8% (0.1–2.8%) of HIV-negative men. Oral HPV was associated with: current smoking (adjusted odds ratio (aOR) 2.2 (95%CI: 1.2–3.9)), time since tooth-brushing (aOR per hour 0.87, 95%CI: 0.8–0.96) and number of lifetime tongue-kissing partners aOR 3.2 95%CI: (1.2–8.4) for 26–100 partners and 4.9 95%CI: (1.9–12.5) for>100 partners. Lifetime oral-penile sex partner numbers were significantly associated in a separate model: aOR 2.8(1.2–6.3) for 26–100 partners and 3.2(1.4–7.2) for>100 partners. HPV 16 and 18 persisted in 10 of 12 men after a median six months. Sensitivities of sampling methods compared to all methods combined were: oral rinse 97%, tampon-absorbed oral rinse 69%, swab 32%. Conclusions Oral HPV was associated with HIV infection, smoking, recent tooth-brushing, and more lifetime tongue-kissing and oral sex partners. The liquid oral rinse sample was more sensitive than a tampon-absorbed oral rinse or a self-collected swab.

Oral mucosal malignancy and potentially malignant lesions: an update on the epidemiology, risk factors, diagnosis and management

An oral examination for the assessment for malignant and potentially malignant oral mucosal lesions is routine in general dental practice. It may be uncommon for general dental practitioners to encounter oral cancer, with anecdotal reports suggesting that this occurs about once every 10 years in a busy general dental practice. However, potentially malignant oral mucosal lesions are relatively common, occurring in about 2.5% of the population. This update highlights the epidemiology, risk factors, diagnosis and management of these oral mucosal lesions.