Clinical roles of autophagy-related proteins Beclin-1 and mTOR in smoking and non-smoking patients with oral leukoplakia

Background

To study the expressions of autophagy-related proteins Beclin-1 and mammalian target of rapamycin (mTOR) in smoking and non-smoking patients with oral leukoplakia (OLK).

Methods

A total of 240 patients diagnosed as OLK from January 2017 to December 2017 were enrolled. Beclin-1 and mTOR expressions were detected by immunohistochemistry. Their clinical data were collected. The correlations of smoking with Beclin-1 and mTOR expressions as well as clinical factors were explored by Spearman's analysis.

Results

There were significant differences in gender ratio, age, lesion location, severity and malignancy between smoking and non-smoking OLK patients (P<0.05). The positive expression rate of Beclin-1 in OLK patients with simple hyperplasia and abnormal hyperplasia in the smoking group was significantly lower than that of the non-smoking group (P<0.05). In the abnormal hyperplasia group, the number of cigarettes daily was significantly positively correlated with mTOR expression (r=0.843, P=0.042). After the simple hyperplasia group was included, there was a positive correlation between smoking age and positive expression rate of mTOR (r=0.942, P=0.012). For number of cigarettes and smoking age, the positive expression rates of Beclin-1 and mTOR showed significant negative correlations (r=-0.952, P=0.003, r=-0.953, P=0.002).

Conclusion

Autophagy-related proteins Beclin-1 and mTOR may be involved in the smoking-induced pathogenesis of OLK.

Deep learning-based pathology image analysis predicts cancer progression risk in patients with oral leukoplakia

BACKGROUND

Oral leukoplakia (OL) is associated with an increased risk for oral cancer (OC) development. Prediction of OL cancer progression may contribute to decreased OC morbidity and mortality by favoring early intervention. Current OL progression risk assessment approaches face large interobserver variability and is weakly prognostic. We hypothesized that convolutional neural networks (CNN)-based histology image analyses could accelerate the discovery of better OC progression risk models.

METHODS

Our CNN-based oral mucosa risk stratification model (OMRS) was trained to classify a set of nondysplastic oral mucosa (OM) and a set of OC H&E slides. As a result, the OMRS model could identify abnormal morphological features of the oral epithelium. By applying this model to OL slides, we hypothesized that the extent of OC-like features identified in the OL epithelium would correlate with its progression risk. The OMRS model scored and categorized the OL cohort (n = 62) into high- and low-risk groups.

RESULTS

OL patients classified as high-risk (n = 31) were 3.98 (95% CI 1.36-11.7) times more likely to develop OC than low-risk ones (n = 31). Time-to-progression significantly differed between high- and low-risk groups (p = 0.003). The 5-year OC development probability was 21.3% for low-risk and 52.5% for high-risk patients. The predictive power of the OMRS model was sustained even after adjustment for age, OL site, and OL dysplasia grading (HR = 4.52, 1.5-13.7).

CONCLUSION

The ORMS model successfully identified OL patients with a high risk of OC development and can potentially benefit OC early diagnosis and prevention policies.

Clinicopathological Evaluation of Tobacco-related Oral Mucosal Lesions

AIM

To clinically evaluate the nature of precancerous and cancerous lesions associated with tobacco consumption habit and to correlate clinical profile with the histopathological findings of clinically suspected precancerous and cancerous lesions.

MATERIALS AND METHODS

These included the examination of patients who visited the outpatient department (OPD) of the institute that includes 1,500 patients who had tobacco chewing habits were classified into the following two groups according to their characteristics. The study group comprised 270 patients, of which 170 gave consent for biopsy and 100 patients who not gave consent were counseled for tobacco cessation.

RESULTS

Among 270 patients, the highest number of patients, 146 (54.07%) patients, were found to be smokeless tobacco consumers followed by 65 (24.07%) patients who were smoked tobacco consumers while 59 (21.85%) patients were found to have both the habits. Wide variation was noted in duration and frequency of habit. Most prevalent site was the buccal mucosa affected in 138 (51.11%) patients who consumed both smoked as well as smokeless tobacco. And on clinical examination, 138 (51%) patients had leukoplakia followed by 54 (20%) patients with oral squamous cell carcinoma and 40 (15%) patients with oral submucous fibrosis (OSMF). Other patients were tobacco pouch keratosis 17 (6%), smoker's melanosis 8 (3%), smoker's palate 7 (3%), and erythroplakia 6 (2%). The patients who gave consent (170 patients) were evaluated histopathologically to correlate with clinical findings.

CONCLUSION

Tobacco-related oral lesions are also high, which brings an alarming signal toward the development of cancer. Our contribution as healthcare providers can be made by conducting more oral health education programs and educating the general population about the adverse effects of tobacco. The appropriate clinical assessment and categorization of all these lesions aided us in motivating patients to undergo necessary treatments and also to discontinue their habits in order to prevent deterioration of their conditions.

CLINICAL SIGNIFICANCE

Set up de-addiction centers in dental colleges and help tobacco users in discontinuing their habits. Interestingly, this study also served as a mirror for those patients who were unaware of the lesions they were giving abode to in their oral cavities.

Chewing tobacco may act as a risk factor for dysplastic transformation of squamous cells in Oral leukoplakia- A cytochemistry based approach

The use of chewing tobacco is a severe risk factor for oral mucosa related diseases including cancer in India as well as USA, although its relationship with Oral Leukoplakia (OL) or related carcinogenicity is still not clear. This work chose two oncogenic pathway proteins- the Epidermal Growth Factor Receptor and the WNT pathway among leukoplakia patients and established their correlation with the individuals' tobacco chewing habit. 89 fresh patients with OL were selected for the work. The samples were classified based on the individual's tobacco chewing habit. The divided samples were then immunostained with antibodies for both of the EGFR as well as WNT pathway proteins. The samples were further classified based on their proliferation status and the expression of these oncoproteins was also observed. In order to compare the cytological data with histological data, 30 OL patients undergoing biopsy were chosen and immunohistological analysis was performed for the same pathways. Results showed overexpressing EGFR and WNT pathway proteins in all OL samples. Structurally atypic cells had a tendency to overexpress these oncoproteins. However the immunocytochemistry data could not confirm any positive effect of chewing tobacco on the OL's proliferative state. Statistical data from the immunfluorescence finally revealed the overexpression of both EGFR and WNT pathway proteins on the proliferative population establishing chewing tobacco as a positive risk factor for the onset of OL. Data from biopsy samples followed the same trend of protein expression seen in the cytological samples. Dysplastic zones showed huge overexpression of EGFR and WNT pathway proteins among tobacco chewers. In conclusion, this is the first time report showing the effect of chewing tobacco on the EGFR and WNT pathway in OL and its possible role as a potential risk factor for its proliferative type.

Recurrence rates after surgical removal of oral leukoplakia-A prospective longitudinal multi-centre study

Oral leukoplakia (OL) is a potentially malignant oral disorder. The Gold Standard treatment is to remove surgically the OL. Despite optimal surgery, the recurrence rates are estimated to be 30%. The reason for this is unknown. The aim of this study was to investigate the clinical factors that correlate with recurrence after surgical removal of OL. In a prospective study data were collected from 226 patients with OL. Forty-six patients were excluded due to incomplete records or concomitant presence of other oral mucosal diseases. Overall, 180 patients proceeded to analysis (94 women and 86 men; mean age, 62 years; age range, 28–92 years). Clinical data, such as gender, diagnosis (homogeneous/non-homogeneous leukoplakia), location, size, tobacco and alcohol use, verified histopathological diagnosis, and clinical photograph, were obtained. In patients who were eligible for surgery, the OL was surgically removed with a margin. To establish recurrence, a healthy mucosa between the surgery and recurrence had to be confirmed in the records or clinical photographs. Statistical analysis was performed with the level of significance set at P<0.05. Of the 180 patients diagnosed with OL, 57% (N = 103) underwent surgical removal in toto. Recurrence was observed in 43 OL. The cumulative incidence of recurrence of OL was 45% after 4 years and 49% after 5 years. Fifty-six percent (N = 23) of the non-homogeneous type recurred. Among snuff-users 73% (N = 8) cases of OL recurred. A non-homogeneous type of OL and the use of snuff were significantly associated with recurrence after surgical excision (P = 0.021 and P = 0.003, respectively). Recurrence was also significantly associated with cancer transformation (P<0.001). No significant differences were found between recurrence and any of the following: dysplasia, site of lesion, size, multiple vs. solitary OL, gender, age, use of alcohol or smoking. In conclusion, clinical factors that predict recurrence of OL are non-homogeneous type and use of snuff.

Variants in FAT1 and COL9A1 genes in male population with or without substance use to assess the risk factors for oral malignancy

A number of genetic variants were suggested to be associated with oral malignancy, few variants can be replicated. The aim of this study was to identify significant variants that enhanced personal risk prediction for oral malignancy. A total of 360 patients diagnosed with oral squamous cell carcinoma, 486 controls and 17 newly diagnosed patients with OPMD including leukoplakia or oral submucous fibrosis were recruited. Fifteen tagSNPs which were derived from somatic mutations were genotyped and examined in associations with the occurrence of oral malignancy. Environmental variables along with the SNPs data were used to developed risk predictive models for oral malignancy occurrence. The stepwise model analysis was conducted to fit the best model in an economically efficient way. Two tagSNPs, rs28647489 in FAT1 gene and rs550675 in COL9A1 gene, were significantly associated with the risk of oral malignancy. The sensitivity and specificity were 85.7% and 85.5%, respectively (area under the receiver operating characteristic curve (AUC) was 0.91) for predicting oral squamous cell carcinoma occurrence with the combined genetic variants, betel-quid, alcohol and age. The AUC for OPMD was only 0.69. The predictive probability of squamous cell carcinoma occurrence for genetic risk score without substance use increased from 10% up to 43%; with substance use increased from 73% up to 92%. Genetic variants with or without substance use may enhance risk prediction for oral malignancy occurrence in male population. The prediction model may be useful as a clinical index for oral malignancy occurrence and its risk assessments.

Prevalence of oromucosal lesions in relation to tobacco habit among a Western Maharashtra population

OBJECTIVES

This study was conducted to determine the number and types of oromucosal lesions (OMLs) in relation to tobacco habits in patients who attended the outpatient department.

METHODOLOGY

A total of 1730 patients visiting the Department of Oral Medicine and Radiology were interviewed and screened for tobacco habits (smoking and smokeless). Clinical oral examination was conducted with diagnostic instruments using the Color Atlas of Common Oral Diseases as a guide for diagnosis. When clinical features were not diagnostic, a biopsy was done.

RESULTS

Of the 1730 outpatients, 975 (56.3% ) individuals used tobacco in one or other forms and 687 (70.4%) of these had OMLs.

CONCLUSION

The results of this study provide important information on the prevalence of OMLs in patients seeking dental care. This provides baseline data for future studies on the prevalence of oral lesions in the general population.

Hepatic Angiosarcoma with Dyskeratosis Congenita

Nail dystrophy, oral leukoplakia and abnormal skin pigmentation are the defining features of dyskeratosis congenita. Dyskeratosis congenita is a disorder of poor telomere maintenance and is known to increase the risk of developing multiple types of malignancy. However, there are few reports of liver tumors arising in dyskeratosis congenita patients. We herein report the second case of hepatic angiosarcoma arising from dyskeratosis congenita: a 23-year-old man was introduced to our hospital due to the detection of multiple tumors in the liver. A histological analysis showed angiosarcoma that stained positive for antibodies to both CD31 and blood coagulation factor VIII.

[Papillomavirus in the genesis of oral leukoplakia]

Immunohistochemical examination of the proliferative activity of cells was made investigating the expression of Ki-67 protein and the location of proteins associated with epithelial cell papillomavirus infection involving P16(INK4a) and HPV16 proteins in different cell areas of the intact mucosa, in leukoplakia with the signs of hyperplasia and dysplasia, and in squamous cell carcinoma. There was a positive correlation between the proliferative activity of cells in the parabasal cell areas and the expression of P16(INK4a) protein in oral leukoplakia with the signs of hyperplasia (r(s)=0.397; p=0.018). In oral leukoplakia with dysplastic changes, there was a positive correlation between the proliferation of cells in the parabasal and prickle cell layers and the location of HPV type 16 antigens (r(s)=0.515; p=0.041 and r(s)=0.651; p=0.006). Detection of papillomavirus infection in leukoplakia can solve not only the problems with its genesis, but this is also a morphological basis for the effective prevention and treatment of this common oral mucosal disease.

The prevalence of HIV associated oral lesions among adults in the era of HAART

INTRODUCTION

The overall prevalence of HIV associated oral lesions among adults has decreased since the advent of highly active anti-retroviral therapy (HAART).

AIMS AND OBJECTIVES

This study describes the prevalence and types of oral mucosal lesions in adults, who accepted a dedicated oral and dental programme for HIV-infected patients. The incidence of oral lesions and the CD4 cell counts on those patients, were related to cases receiving HAART and to those who were not.

DESIGN

This was a retrospective, descriptive cross-sectional study.

METHODS

Patients were interviewed, using a structured questionnaire to obtain information regarding medical history, current medications and demographic details. Data relating to CD4 cell counts were extracted from clinical medical records of the patent. In each case, the oral cavity of the sitting patient was examined under artificial light, by a clinician using a mouth mirror. Oral lesions were categorised in accordance with EC-Clearinghouse diagnostic criteria.

RESULTS

The prevalence of HIV-associated oral lesions was significantly reduced (p < 0.001) in patients receiving HAART. There was, however, no significant difference (p = 0.29) in mean CD4 counts between patients receiving HAART and those not receiving HAART. The presence of oral lesions was statistically significantly, associated with both CD4 counts of < 200 cells/mm3 (p < 0.001) and the absence of HAART (p = 0.033).

CONCLUSIONS

The study confirmed that the incidence of oral lesions and of pseudo-membranous candidiasis in particular, were statistically significantly reduced in patients receiving HAART.

[A woman with thick nails and a white tongue]

A 22-year-old women visited the dermatologist with hypertrophic finger- and toenails, palmoplantar keratoderma and oral leukokeratosis since her childhood. The diagnosis 'pachyonychia congenita type 1' was made. This is a rare dermatosis with an autosomal dominant inheritance pattern. The treatment is symptomatic.

Interactions between cigarette smoking and polymorphisms of xenobiotic-metabolizing genes: the risk of oral leukoplakia

BACKGROUND

This case-control study investigates the role of xenobiotic-metabolizing genes, including glutathione S-transferases (GSTs) and cytochrome P450 1A1 (CYP1A1) and 2E1 (CYP2E1), in the susceptibility to oral potentially malignant disorders (OPMDs).

METHODS

The genotypes of GSTM1, GSTT1, GSTP1, CYP1A1*2C, and CYP2E1 PstI/RsaI polymorphisms were determined for 217 OPMD cases and 492 age- and sex-matched controls from a Taiwanese penitentiary.

RESULTS

Compared to the GSTM1-present genotype, the GSTM1-null genotype was significantly associated with increased risk of leukoplakia (odds ratio [OR]=1.46, 95% confidence interval [CI]=1.01-2.10). Similarly, compared to the CYP1A1*2C A/G+G/G genotype, the CYP1A1*2C A/A genotype was significantly associated with increased risk of leukoplakia (OR=1.64, 95% CI=1.12-2.40), particularly for smokers consuming > 13 pack-years of cigarettes (OR=2.40, 95% CI=1.40-4.11) (Interaction P=0.039). In addition, participants with 4-5 risk genotypes (OR > 1) experienced higher risks for leukoplakia than those with 0-1 risk genotypes (OR=3.19, 95% CI=1.65-6.15) (Trend test P=0.001).

CONCLUSIONS

Our findings suggest that the CYP1A1*2C A/A genotype may increase the risk of leukoplakia, especially for heavy smokers. Xenobiotic-metabolizing genes may simultaneously modulate this disease risk. These observations require further confirmation with larger samples.

Effect of methylxanthines (coffee/tea consumers) on oral precancer and oral cancer patients with smoking and smokeless tobacco habits

AIM

To study, whether the consumption of regular tea/coffee (methylxanthines) increases the risk of oral cancer in patients with smoking and smokeless tobacco habits.

MATERIALS AND METHODS

This study was conducted on a total of 90 oral cancer and precancerous patients, from western Maharashtra (India) males in the age group of 20 to 45 years who were with smoking and smokeless tobacco habits; also regular tea/coffee consumers were subjected to biochemical parameters such as aspartate transaminase (AST) and alanine transaminase (ALT) from saliva and serum of patients with oral precancer (submucous fibrosis, leukoplakia) and oral cancer patients and compared with 90-age and sex-matched controls. Individuals consent was taken to measure their biochemical parameters, by using Hafkenscheid method in whole saliva and serum. Statistical analysis of variance (ANOVA) with Tukey's correction for multiple group comparisons was performed using Student t-test.

RESULTS

Results show, that a statistically significant increase in value (p < 0.05) in ALT, AST in both saliva and serum was observed in precancerous and oral cancer patients among the study group as compared to the control group.

CONCLUSION

In the present study, there was increase in the levels of ALT, AST enzymes in both saliva and serum levels in the study group as compared to the control group which was statistically significant (p < 0.05) suggesting that long-term exposure of methylxanthines results in impairment of salivary gland antioxidant system which may affect the anticarcinogenic action of saliva.

CLINICAL SIGNIFICANCE

Oral fluids may be utilized effectively to study the variations in the biochemical constituents of saliva of leukoplakia, submucous fibrosis and oral cancer patients.

Significance of cannabis use to dental practice

The illicit use of the three main forms of cannabis-marijuana, hash, hash oil-pose certain obstacles and challenges to the dental professional. There are a number of systemic, as well as oral/head and neck manifestations, associated with cannabis use. Dentists need to be aware of these manifestations in order to take whatever precautions and/or modifications to the proposed treatment that might be necessary.

Attitudes of Italian dental and dental hygiene students toward tobacco-use cessation

OBJECTIVE

The aim of this study was to investigate the smoking habits of Italian dental and dental hygiene students and to assess their knowledge on the health effects of cigarette smoking and their attitudes toward tobacco-use cessation (TUC) in dental practice.

MATERIALS AND METHODS

Data was collected from 220 students attending the Dental and Dental Hygiene Schools (DS and DHS, respectively) at the University of Palermo (Italy).

RESULTS

The percentage of smokers amongst DS and DHS students was similar (32.78% vs. 32.5%) with 67.77% of DS students and 77.5% of DHS agreeing that the damages to health caused by smoking were covered in their didactic course work. A high percentage of DS (63.33%) and DHS (67.5%) students reported the relationship between smoking and a number of associated health conditions. Both DS and DHS students showed poor knowledge of TUC interventions. Both DS and DHS students reported to be conscious of their own role as a counsellor, with DHS students feeling more comfortable in approaching counselling in clinical practice. Although DS and DHS students reported a positive attitude toward TUC interventions, almost half of the students had some concerns about the effectiveness of smoking cessation activities.

DISCUSSION

The introduction of a comprehensive tobacco education curriculum in DS and DHS programs could further improve students' perceptions and attitudes and provide knowledge and clinical experience which would lead to the incorporation of TUC into subsequent professional practice.

Oral health risks of tobacco use and effects of cessation

The purpose of this paper is to review the epidemiologic evidence for the effects of tobacco use and tobacco use cessation on a variety of oral diseases and conditions. Exposures considered include cigarette and bidi smoking, pipe and cigar smoking, and smokeless tobacco use. Oral diseases and disorders considered include oral cancer and precancer, periodontal disease, caries and tooth loss, gingival recession and other benign mucosal disorders as well as implant failure. Particular attention is given to the impact of tobacco use cessation on oral health outcomes. We conclude that robust epidemiologic evidence exists for adverse oral health effects of tobacco smoking and other types of tobacco use. In addition, there is compelling evidence to support significant benefits of tobacco use cessation with regard to various oral health outcomes. Substantial oral health benefits can be expected from abstention and successful smoking cessation in a variety of populations across all ages.

Oral mucosal findings related to tobacco use and alcohol consumption: a study on Swiss army recruits involving self-reported and clinical data

PURPOSE

The aim of the present study was to assess the oral mucosal health status of young male adults (aged 18 to 24 years) in Switzerland and to correlate their clinical findings with self-reported risk factors such as tobacco use and alcohol consumption.

MATERIALS AND METHODS

Data on the oral health status of 615 Swiss Army recruits were collected using a standardised self-reported questionnaire, followed by an intraoral examination. Positive clinical findings were classified as (1) common conditions and anatomical variants, (2) reactive lesions, (3) benign tumour lesions and (4) premalignant lesions. The main locations of the oral mucosal findings were recorded on a topographical classification chart. Using correlational statistics, the findings were further associated with the known risk factors such as tobacco use and alcohol consumption.

RESULTS

A total of 468 findings were diagnosed in 327 (53.17%) of the 615 subjects. In total, 445 findings (95.09%) were classified as common conditions, anatomical variants and reactive soft-tissue lesions. In the group of reactive soft-tissue lesions, there was a significantly higher percentage of smokers (P < 0.001) and subjects with a combination of smoking and alcohol consumption (P < 0.001). Eight lesions were clinically diagnosed as oral leukoplakias associated with smokeless tobacco. The prevalence of precursor lesions in the population examined was over 1%.

CONCLUSIONS

Among young male adults in Switzerland, a significant number of oral mucosal lesions can be identified, which strongly correlate with tobacco use. To improve primary and secondary prevention, young adults should therefore be informed more extensively about the negative effects of tobacco use on oral health.

[Analysis of risk factors for carcinogenesis of oral leukoplakia]

OBJECTIVE

To investigate the risk factors for malignant transformation of oral leukoplakia.

METHODS

A total of 409 cases with oral leukoplakia was retrospectively analyzed. Single factor test was first performed to examine the associations between oral leukoplakia's histopathological classification and each of risk factors including sex, age, systemic diseases, course of disease, clinical classification, site, size, numbers of lesion, alcohol and tobacco consumption, and symptom. Then the association of these selected factors with oral leukoplakia's histopathological classification was evaluated using multiple logistic regression analysis.

RESULTS

Fifty-two cases of all 409 patients with oral leukoplakia (including 9 severe dysplasia) developed oral cancer. The ratio of malignant transformation was 12.7%. Sex, age, clinical type, site and symptom were chosen as risk factors incorporated into the multiple logistic regression models. The risk of mild-moderate dysplasia in female was 2.40 times as high as that in male. The risk of mild-moderate dysplasia of speckled leukoplakia was 2.81 times as high as that of homogeneous leukoplakia. The risk of mild-moderate dysplasia of dangerous site was 1. 98 times as high as that non-dangerous site. The risk of mild-moderate dysplasia with symptom was 1.84 times as high as that without symptom. The risk of severe dysplasia and oral cancer in female was 3.11 times as high as that in male. The risk of severe dysplasia and oral cancer of speckled (4.50 times), ulcerative (5.63 times), verrucous leukoplakia (4.09 times) were much higher than that of homogeneous leukoplakia. The risk of severe dysplasia and oral cancer in dangerous site was 2.79 times as high as in non-dangerous site. The risk of severe dysplasia and oral cancer in leukoplakia with symptom was 4.38 times as high as without symptom.

CONCLUSIONS

The malignant transformation of oral leukoplakia is correlated to sex, clinical type, site and symptom.

Variant haplotypes at XRCC1 and risk of oral leukoplakia in HPV non-infected samples

BACKGROUND

One of the mechanisms in human papillomavirus (HPV)-related carcinogenesis is inhibition of DNA repair by HPV oncoprotein. In this study, we investigated whether polymorphisms at XRCC1, one of the DNA repair loci, could modulate the risk of tobacco-related leukoplakia and cancer in HPV-infected individuals.

METHODS

Tissue DNA from 83 oral cancer, 91 leukoplakia and 100 healthy controls were screened for HPV 16/18 infection and polymorphisms at XRCC1 by PCR-RFLP to estimate the risk of diseases independently and jointly.

RESULTS

Human papillomavirus infection was significantly associated with increased risk of leukoplakia and cancer (OR = 2.8, 95% CI = 1.2-6.5 and OR = 5.5, 95% CI = 1.6-19, respectively). Independently, genotypes at three polymorphic sites on XRCC1 did not modulate the risk of diseases but pooled variant haplotypes increased the risk of leukoplakia in overall and HPV non-infected (OR = 1.8, 95% CI = 1.2-2.8; OR = 2.2, 95% CI = 1.2-4.0, respectively) samples but not that of cancer.

CONCLUSION

The association between variant haplotypes at XRCC1 and risk of leukoplakia is pronounced in non-infected individuals since HPV oncoprotein could inhibit directly the DNA repair activity of XRCC1. But more samples of leukoplakia and cancer are essential to validate these results.

[Smokeless tobacco: a new risk factor for oral health? A review]

Due to migration of different ethnic groups, mainly from Africa and Asia, into Switzerland, many traditional products and habits that have not been seen before were also introduced. Smokeless tobacco (ST)--as one of those habits--is a product of increased use in Switzerland, although no sound epidemiological data are presently available. Numerous studies from North-America, Sweden, Asia and Africa could verify the carcinogenic potency of smokeless tobacco and its effects in the developement of oral cancer and different systemic disorders. For dental professionals and their team it is important to detect ST-associated lesions, and to tell the patients about the potential harmful sequelae of ST products. The present review focusses on the different types of RT products and their effects on oral health.

Betel quid not containing tobacco and oral leukoplakia: a report on a cross-sectional study in Papua New Guinea and a meta-analysis of current evidence

Leukoplakia is an asymptomatic, potentially malignant change in the oral mucosa. Previous studies have reported that smoking and betel quid chewing are associated with increased risk of leukoplakia; few studies have reported on these associations in populations where betel quid does not contain tobacco. We conducted a case-control study nested in a cross-sectional study in Papua New Guinea and a systematic review of studies that included chewers of betel quid without tobacco. Our study recruited 1,670 adults. We recorded betel quid chewing and smoking. The prevalence of leukoplakia was 11.7%. In the nested case-control study of 197 cases and 1,282 controls, current betel chewing was associated with increased risk of leukoplakia with an adjusted odds ratio for current chewers of 3.8 (95% CI 1.7, 8.4) and in the heaviest chewers of 4.1 (95% CI 1.8, 9.1) compared to non-chewers. Current smoking was associated with an increased risk of leukoplakia with an adjusted odds ratio for current smokers of 6.4 (95% CI 4.1, 9.9) and amongst heaviest smokers of 9.8 (95% CI 5.9, 16.4) compared to non-smokers. The systematic review identified 5 studies examining risk of leukoplakia associated with betel quid chewing in populations where betel quid did not contain tobacco and that controlled for smoking. In studies that adjusted for smoking, the combined random effect odds ratio was 7.9 (95% CI 4.3, 14.6) in betel quid chewers. The results of this study and systematic review of similar studies provide evidence of the role of betel quid not containing tobacco and leukoplakia.

[Oral erythroplakia and erythroleukoplakia: red and red-white dysplastic lesions of the oral mucosa--part 1: epidemiology, etiology, histopathology and differential diagnosis]

Oral erythroplakia (OE) and oral erythroleukoplakia (OEL; synonym: speckled leukoplakia) are working diagnoses for red and red-white lesions of the oral mucosa after exclusion of all other possible diagnoses for lesions with a similar clinical appearance. A good knowledge of oral medicine and possible differential diagnoses of oral mucosal pathologies is mandatory to correctly detect OE and OEL on this exclusion basis. In the present review article in a series of two, epidemiologic data, etiologic factors, possible differential diagnoses, and the histopathologic characteristics of OE and OEL will be presented and discussed regarding the current literature. A thorough histopathologic examination of these epithelial precursor lesions is mandatory to recognise the presence and the severity of epithelial dysplasia, which is a decisive factor for the subsequent treatment planning.

Dose-response relationships of oral habits associated with the risk of oral pre-malignant lesions among men who chew betel quid

Betel quid, cigarettes and alcohol are well-recognized risk factors for oral cancer. However, the combined effect of the frequency and duration of these oral habits on the risk for developing oral pre-malignancies among betel quid users has not been fully addressed. In this study, an oral screening programme for men chewing betel quid was carried out by well-trained dentists for early detection of oral pre-malignancy lesions. Using generalized logit model and proportional odds model, we found that, compared with the occasional user, the adjusted odds ratios of developing leukoplakia for men chewing one to 10 pieces of betel quid, 11-20 pieces, and more than 20 pieces per day were estimated as 2.14 (95% confidence interval [CI] 1.62-2.81), 2.99 (95% CI 2.06-4.27), and 5.37 (95% CI 3.76-7.47), respectively. The corresponding figures for erythroleukoplakia were 3.69 (95% CI 1.55-8.79), 13.78 (95% CI 5.76-32.98), and 36.64 (95% CI 15.94-84.16), respectively. Similar results were found while the duration was considered. The dose-response relationships were not as noteworthy for cigarette and alcohol drinking.

Oral cancer

Five percent of all tumors occur in the head and neck, and approximately half of those occur specifically in the oral cavity. Of the 615,000 new cases of head and neck [corrected] tumors reported worldwide in 2000, 300,000 were primary oral cavity squamous cell carcinomas. Recent data from the Surveillance, Epidemiology, and End Results Program suggest that 28,900 new cases of oral cancer will be identified and 7400 deaths attributed to oral cancer each year in the United States. The sixth leading cause of cancer-related mortality, oral cancer accounts for 1 death every hour in the United States. However, despite advances in screening tools, imaging technology, and access to primary care physicians, a considerable percentage of patients present with advanced-stage disease. Clinical signs and symptoms of head and neck tumors are often nonspecific and may be mistaken for other common ailments. Primary care physicians must be aware of the possibility of oral cancer, particularly the increasing incidence in young patients without traditional risk factors of alcohol and tobacco abuse. To improve survival, all patients should be routinely and vigilantly screened for oral mucosal lesions.

Oral lesions in HIV-positive dental patients--one more argument for tobacco smoking cessation

OBJECTIVE

To determine the prevalence of oral lesions associated with human immunodeficiency virus (HIV) in a population of dental patients and analyze its association with psycho-social variables and biological markers.

STUDY DESIGN

The dental charts of 415 dental patients consecutively treated between May and July 2005 in a dedicated HIV dental clinic were reviewed. Oral soft tissue examinations, psycho-social and medical variables were extracted and recorded for each patient. Ethnicity, gender, HIV treatment, peripheral CD(4) counts and tobacco usage were analyzed in correlation with oral lesions associated with HIV.

RESULTS

Fifty-five percent of all subjects had at least one oral lesion associated with HIV, with oral candidiasis, salivary gland enlargement and oral hairy leukoplakia being the most commonly observed conditions. Gender and ethnicity did not correlate with a higher prevalence in lesions. However, tobacco smoking correlated significantly with a higher prevalence of oral lesions, independent of CD(4) counts.

CONCLUSIONS

These findings suggest that oral lesions remain commonly observed morbidities among HIV-infected dental patients independent of gender and ethnicity and that tobacco usage is a major and often underestimated risk factor for those lesions.

Polymorphisms at XPD and XRCC1 DNA repair loci and increased risk of oral leukoplakia and cancer among NAT2 slow acetylators

Polymorphisms at N-acetyl transferase 2 locus (NAT2) lead to slow, intermediate and rapid acetylation properties of the enzyme. Improper acetylation of heterocyclic and aromatic amines, present in tobacco, might cause DNA adduct formation. Generally, DNA repair enzymes remove these adduct to escape malignancy. But, tobacco users carrying susceptible NAT2 and DNA repair loci might be at risk of oral leukoplakia and cancer. In this study, 389 controls, 224 leukoplakia and 310 cancer patients were genotyped at 5 polymorphic sites on NAT2 and 3 polymorphic sites on each of XRCC1 and XPD loci by PCR-RFLP method to determine the risk of the diseases. None of the SNPs on these loci independently could modify the risk of the diseases in overall population but variant genotype (Gln/Gln) at codon 399 on XRCC1 and major genotype (Lys/Lys) at codon 751 on XPD were associated with increased risk of leukoplakia and cancer among slow acetylators, respectively (OR = 4.2, 95% CI = 1.2-15.0; OR = 1.6, 95% CI = 1.1-2.3, respectively). Variant genotype (Asn/Asn) at codon 312 on XPD was also associated with increased risk of cancer among rapid and intermediate acetylators (OR = 1.9, 95% CI = 1.2-2.9). Variant C-G-A haplotype at XRCC1 was associated with increased risk of leukoplakia (OR = 1.7, 95% CI = 1.2-2.4) but leukoplakia and cancer in mixed tobacco users (OR = 3.1, 95% CI = 1.4-7.1, OR = 2.4, 95% CI = 1.1-5.4, respectively) among slow acetylators. Although none of the 3 loci could modulate the risk of the diseases independently but 2 loci in combination, working in 2 different biochemical pathways, could do so in these patient populations.

[Changes in oral mucosa of the partially edentulous who wear removable partial dentures ]

PURPOSE

to confirm or infirm structural modification of oral mycosis at the summit after fifteen days of wearing removable resin partial dentures.

METHODS

our study took place at the health center of Rufisque in Senegal from January to July 1998, involved fourteen patients divided into two groups according to sex: seven males and seven females who came for removable resin partial dentures. The macroscopic examination was conducted through to inspection and touching of mycosis at the level of toothless summit before the wearing of the denture. A biopsy was conducted on each patient before and after the wearing of the resin dentures. Tissue reaction was appreciated qualitatively through morphological analysis.

RESULTS

Before the wearing of the removable resin partial dentures 92.9% of patients had epithelial hyperplasia; 7.1% epithelial hypoplasia and 85.7% keratosis at the level of the chorion the number of collagen fibbers (28.6% discrete, 50% moderate, 21.4% important), fibroblasts (35.7% discrete; 42.9% moderate ; 21.4% important), inflammatory cells (71.4% discrete; 28.6% moderate; 0% important) and for blood vessels (64% discrete; 35.70% moderate; 0% important) after fifteen days of wearing partial denture. After fifteen days of the wearing removable resin partial dentures: 85.7% of patients had epithelial hyperplasia; 14.3% normal epithelial and 100% de keratosis at the level of the chorion the number of collagen fibbers (14.3% discrete; 21.4% moderate; 64.3% important), fibroblasts (42.9% discrete; 42.90% moderate; 14.3% important), inflammatory cells (50% discrete, 35.7% moderate: 14.3% important), blood vessels (43% discrete; 28.6% moderate; 28.6% important).

CONCLUSION

Biopsies of the summit are reliable contribution; they provide precise information on the quality of tissue supporting resin partial dentures. This tissues may seem healthy appearance (inspection and touching) but show sign of suffering at this anatomy-pathological examination.

A review of premalignant oral conditions

The value of mass oral cancer screenings has come under scrutiny, as a consequence of a lack of improvement in the long-term outcomes associated with oral carcinoma over the past several decades. However, it is generally accepted that most oral carcinomas are preceded by visible changes to the mucosa and certain high risk lesions have been identified. The responsibility to evaluate the mucosal tissues of the oral cavity clearly falls under the purview of the dentist. The dentist must clearly grasp the distinction between reactive lesions which usually change in 7 to 14 days and malignant and premalignant lesions which do not. Therefore, appropriate diagnostic procedures (i.e., biopsy of the lesion) must be implemented as a matter of course in the evaluation of any lesion that does not respond to usual therapy in 7 to 14 days.

Oral cancer education in dental schools: knowledge and experience of Nigerian undergraduate students

The objective of this study was to determine the knowledge and experiences of clinical dental students of the College of Medicine, University of Lagos, Nigeria related to the management and prevention of oral malignancy and premalignancy. A self-administered questionnaire was distributed to all clinical dental students. Most of the students (87.7 percent; n=57) had witnessed at least a patient with oral malignancy, while 61.5 percent (n=40) had witnessed or examined a patient with oral premalignancy. While 61.5 percent of the students had observed biopsies of malignant and premalignant lesions, only 13.8 percent (n=9) had ever performed one under supervision. All the respondents believed that oral malignancy is always or sometimes associated with pain, and most of the students were more familiar with the late signs of oral malignancy than the early signs. Almost two-thirds (64.6 percent) of the respondents believed that oral screening programs were effective for early diagnosis and management of oral malignancies. This study revealed a need for a more structured teaching program with increased emphasis on the early signs and symptoms of oral malignancies and involvement of the students in the examination and biopsies of malignant and premalignant lesions.

Long-term treatment outcome of oral premalignant lesions

The purpose of the present retrospective study was to learn the long-term outcome of oral premalignant lesions, leukoplakia and erythroplakia, with or without surgical intervention and to relate the outcome to factors supposed to be significant for malignant development including clinical type, demarcation, size, site, presence of epithelial dysplasia, smoking and surgery. A total of 269 lesions in 236 patients were included. Ninety-four lesions were surgically removed, 39 lesions (41%) being homogenous and 46 (49%) non-homogenous leukoplakias whereas nine (5%) were erythroplakias. Seventy-three percent of the lesions were associated with tobacco habits. The mean size of the lesions was 486 mm(2), and 71% of the lesions showed a degree of epithelial dysplasia. After excision the defects were closed primarily by transposition of mucosal flaps or they were covered by free mucosal or skin grafts. A few defects were left for secondary healing. After surgical treatment the patients were followed (mean 6.8 yrs, range 1.5-18.6 yrs), and new biopsies taken in case of recurrences. One hundred and seventy five lesions had no surgical intervention, 149 lesions (85%) being homogenous and 20 (11%) non-homogenous leukoplakias, and 6 (3%) erythroplakias. Eighty-one percent of the lesions were associated with smoking. The mean size of the lesions was 503 mm(2) and 21 of the lesions (12%) exhibited epithelial dysplasia. Sixty-five lesions were not biopsied. These patients were also followed (mean 5.5 yrs, range 1.1-20.2 yrs), and biopsies taken in case of changes indicative of malignant development. All patients were encouraged to quit smoking and candidal infections were treated. The possible role of different variables for malignant development was estimated by means of logistic regression analysis. Following surgical treatment 11 lesions (12%) developed carcinoma after a mean follow-up period of 7.5 yrs. Non-homogenous leukoplakia accounted for the highest frequency of malignant development, i.e. 20%, whereas 3% of the homogenous leukoplakias developed carcinomas. Surgically treated lesions with slight, moderate, severe and no epithelial dysplasia developed carcinoma with similar frequencies, i.e. 9-11%. Without surgical intervention 16% of the 175 lesions disappeared whereas seven lesions (4%) developed carcinoma after a mean observation period of 6.6 yrs. The highest frequency of malignant development (15%) was seen for non-homogenous leukoplakias, this figure being 3% for homogenous leukoplakias. Fourteen percent of lesions with slight epithelial dysplasia developed malignancy and 2% of lesions with no dysplasia showed malignant transformation. Logistic regression analysis showed a seven times increased risk (OR = 7.0) of non-homogenous leukoplakia for malignant development as compared with homogenous leukoplakia and a 5.4 times increased risk for malignant development for lesions with a size exceeding 200 mm(2). No other examined variables including presence of any degree of epithelial dysplasia, site, demarcation, smoking and surgical intervention were statistically significant factors for malignant development.

Oral cancer and pre-cancer in Myanmar: a short review

Cancer in Myanmar is one of the 10 leading causes of morbidity and mortality. In 1974, the Yangon Cancer Registry was established. From 1974 to 2001 a total of 85 298 cancer cases were registered. From 1963 to 1972 the average annual incidence rate of oral cancer was calculated to be 363 per 100 000 population. The tongue was mostly affected (31.2%). In one study, the prevalence of oral leukoplakia was 1.7%, erythroplakia 0.1%, and submucous fibrosis 0.1%. No epidemiologic studies of the prevalence of betel quid chewing (BQC) in Myanmar have been performed. One study showed that among 773 individuals over the age of 6 years, 46.4% were habitual smokers. A recent symposium on oral health stressed the necessity to introduce concepts of prevention, focusing on BQC habits and smoking as high-risk factors for oral cancer and pre-cancer in Myanmar.

Proliferative verrucous leukoplakia and field cancerization: report of a case

Proliferative verrucous leukoplakia (PVL) is a multi-focal oral pre-malignant lesion, proliferative in nature, with a tendency to recur despite adequate therapy, and a high rate of malignant transformation. The field cancerization phenomenon may explain the characteristic behaviour of PVL. A case of PVL is presented and the field cancerization concept is discussed.

Kindler syndrome

Kindler syndrome is a rare autosomal recessive disorder associated with skin fragility. It is characterized by blistering in infancy, photosensitivity and progressive poikiloderma. The syndrome involves the skin and mucous membrane with radiological changes. The genetic defect has been identified on the short arm of chromosome 20. This report describes an 18-year-old patient with classical features like blistering and photosensitivity in childhood and the subsequent development of poikiloderma. The differential diagnosis of Kindler syndrome includes diseases like Bloom syndrome, Cockayne syndrome, dyskeratosis congenita, epidermolysis bullosa, Rothmund-Thomson syndrome and xeroderma pigmentosum. Our patient had classical cutaneous features of Kindler syndrome with phimosis as a complication.

8-Nitroguanine formation in oral leukoplakia, a premalignant lesion

Oral leukoplakia is a premalignant lesion associated with development of oral cancer. To clarify the mechanism of development of oral carcinogenesis from leukoplakia, we examined DNA damage in oral epithelium of biopsy specimens of patients with leukoplakia by immunohistochemical methods. Histological changes, such as epithelial dysplasia and infiltration of inflammatory cells were observed in oral tissues of leukoplakia patients. A double immunofluorescence labeling study demonstrated that the accumulation of mutagenic 8-nitroguanine, an indicator of nitrative DNA damage, and 8-oxo-7,8-dihydro-2'-deoxyguanosine, an indicator of oxidative DNA damage, was apparently observed in the oral epithelium of patients with leukoplakia, whereas little or no immunoreactivity was observed in normal oral mucosa. Expression of inducible nitric oxide synthase (iNOS) was also observed in oral epithelium of leukoplakia patients. Immunoreactivity of 3-nitrotyrosine, an indicator of nitrative stress, was observed in oral epithelial cells and colocalized with 8-nitroguanine. Moreover, proliferating cell nuclear antigen and p53 were expressed in 8-nitroguanine-positive epithelial cells in the basal layer. These results suggest that iNOS-mediated nitrative stress contributes to development of oral carcinogenesis from leukoplakia through DNA damage as well as oxidative stress.

A stochastic model of cancer initiation including a bystander effect

A stochastic model of cancer initiation is considered. The model is used to evaluate whether a bystander effect may be important in the pre-malignant and malignant stages of carcinogenesis, and furthermore, on the basis of epidemiological data, to estimate the mutation rates of genes involved in the development of oral leukoplakias. The bystander effect is defined here as the capability of oncogenic mutations to increase the mutation probability of neighbouring (bystander) cells, thus leading potentially to a cascade of neighbouring mutated and neoplastic cells as a pre-stage in the development to leukoplakias and cancer. We find that incidence data for oral cancer are indeed in accordance with a significant bystander effect, operating either alone or in combination with genomic instability in the early stages of carcinogenesis, i.e. the development of neoplasia. Simulations performed gave a picture of how mutations and neoplasia may spread in a tissue, to form characteristic leukoplakias with a core of neoplastic cells. The model also showed that the probability of finding at least one neoplastic cell in the tissue after a given number of years is more sensitive to changes in genomic instability within the cell itself than to changes in a bystander effect. Based on epidemiological data we also calculate the maximum number of oncogenic genes that may be involved in the bystander effect and development of genomic instability. Even if capable of explaining the initial development of oncogenic mutations towards neoplastic cells, the bystander model could not reproduce the observed incidence rates of leukoplakia without assuming a carcinogen mutation probability per cell per year of neoplastic cells practically equal to one. This means that the bystander effect, to be of substantial importance in the final development of neoplastic cells towards leukoplakias, requires a very significant increase in mutation probabilities for bystanders to neoplastic cells. Alternatively, additional mechanisms such as abnormal cell differentiation and uncontrolled proliferation and apoptotis in the neoplastic stage may be of major importance during the development to cancerization.

Risk of oral nonmalignant lesions associated with human papillomavirus infection, betel quid chewing, and cigarette smoking in Taiwan: an integrated molecular and epidemiologic study

CONTEXT

In contrast to previous studies about the association of oral squamous cell carcinoma with human papillomavirus (HPV) 16/18, the associations between nonmalignant oral lesions (chronic inflammation, submucous fibrosis, leukoplakia, and squamous papilloma) and HPV are much less well understood.

OBJECTIVE

We conducted this study using an in situ polymerase chain reaction in situ hybridization assay, which is one of the most sensitive methods for in situ viral detection. Other known oral cancer risk factors, including betel quid chewing and cigarette smoking, were also analyzed.

DESIGN

Oral specimens from 23 patients with submucous fibrosis, 36 patients with leukoplakia, 22 patients with squamous papilloma, and 21 patients without significant lesions were analyzed for the presence of HPV DNA. Their betel quid chewing and cigarette smoking histories were reviewed.

RESULTS

HPV-16 and HPV-18 were frequently identified in all 3 oral lesions (61.5% and 42.1%), while HPV-6 and HPV-11 were seen only in squamous papilloma (21.1% and 5.0%). HPV-18, betel quid chewing, and smoking were significantly associated with leukoplakia and squamous papilloma, while only betel quid chewing and smoking were significantly associated with submucous fibrosis. Multivariate analysis showed that the betel quid chewing habit remained an independent factor for leukoplakia and squamous papilloma.

CONCLUSIONS

Our data indicated that betel quid chewing and smoking habits are 2 important risk factors for these nonmalignant or premalignant oral lesions, while for high-risk HPV, only HPV-18--not HPV-16--is a significant risk factor for leukoplakia and squamous papilloma.

Carcinoma and dysplasia in oral leukoplakias in Taiwan: prevalence and risk factors

OBJECTIVES

The issue of existence of malignancy within oral leukoplakia has seldom been addressed in Taiwan. The aims of this study were to investigate the prevalence of carcinoma and dysplasia within oral leukoplakia at the time of clinical diagnosis and to identify the associated risk factors in Taiwan.

STUDY DESIGN

The prevalence rate of malignancy and dysplasia in 1046 oral leukoplakias at a university hospital was calculated. Univariate and multivariate analyses by the Mantel-Haenszel method and multiple logistic regression model were performed to examine risk factors associated with the presence of carcinoma and dysplasia within the lesions.

RESULTS

The prevalence rate of carcinoma was 12.9%. The relative risks for the presence of malignancy in leukoplakias on the tongue/floor of mouth and with nonhomogeneous appearance were 2.72- and 28.13-fold by multivariate logistic regression analysis, when compared with those on buccal mucosa and lesions having homogeneous surface (both P < .05). In contrast, patients who both smoked and chewed betel quid had a significantly lower risk for carcinoma than the abstainers (P < .05). A synergistic effect between the 2 major risk factors of clinical appearance and lesion site was evident. Nonhomogeneous leukoplakia on tongue/floor of mouth had a 43.10-fold higher risk compared to homogeneous lesions located on buccal mucosa or other sites (P < .05). However, homogeneous leukoplakia in buccal mucosa or other sites of the oral cavity still had the possibility of having carcinoma within the lesion. The prevalence of dysplasia was 45.6% among the noncancerous leukoplakias with risk factors similar to those for carcinoma.

CONCLUSIONS

Our results demonstrate that some leukoplakias contain a malignant component. Lesions with certain features are more prone to carcinoma, but no clinical attributes can bring certitude. Therefore, all oral leukoplakias should be submitted to microscopic analysis before any definite treatment or long-term follow-up.

Oral lesions of 500 habitual psychoactive substance users in Chennai, India

The aim of this study was to ascertain the prevalence of oral lesions among 500 psychoactive substance users in a hospital-based population. The study group consisted of 500 consecutive patients attending TTK Hospital, a non-governmental organisation involved in rehabilitation of substance users. Patient history was recorded in a pre-determined format and clinical findings were recorded by a trained physician and dental surgeons. Psychoactive substances used by the patients were alcohol (97%), tobacco (72%), arecanut (57.2%), narcotics (6.8%), cannabis (3.2%) and benzodiazipines (1.8%). Ninety-one percent of patients had one or more oral lesions: dental caries (39%), gingivitis (37.6%), extrinsic stains (24%), oral submucous fibrosis (OSF) (8%), periodontitis (7.4%), leukoplakia (6.6%), melanosis (5.2%), nicotina palatini (2.2%) and erythroplakia (0.6%). For OSF, those using arecanut and alcohol had an odds ratio (OR) of 2.4 [95% confidence intervals (CI) 1.23-4.69, P=0.009], smokers using arecanut products and alcohol had an OR of 3.07 (95% CI 1.59-5.91, P=0.000), and smokers who chewed arecanut products and used drugs had an OR of 23.1 (95% CI 2.05-260, P=0.001) compared with the general population. Those who smoked and used alcohol, arecanut and drugs had a 20.67-fold higher risk of developing leukoplakia compared with those who did not engage in these habits. In conclusion, 91% of patients had one or more oral lesions that needed dental treatment, and most patients were not aware of their oral lesions. The high prevalence of OSF and leukoplakia in substance abusers compared with the general population emphasises the need for regular dental assessments in these patients.

Association between diabetes mellitus and pre-malignant oral diseases: A cross sectional study in Kerala, India

Recent studies have suggested role of diabetes mellitus in the development of periodontal diseases, oral inflammatory and neoplastic lesions. We analysed data from randomised oral cancer screening trial in Kerala, India, to study the association between chronic diseases in general, diabetes mellitus in particular, and pre-malignant oral lesions and conditions. A total of 927 subjects with oral leukoplakia, 170 with oral submucous fibrosis, 100 with erythroplakia lesions and 47,773 apparently healthy subjects constituted the cases and controls respectively for our present study. The odds ratio (OR) for oral leukoplakia among women with a history of diabetes mellitus was found to be 2.0 (95% confidence interval (CI) = 1.4-2.9) whereas that for erythroplakia was 3.2 (95% CI = 1.3-7.9), after adjusting for potential confounders. No statistically significant association between diabetes mellitus and oral submucous fibrosis and pre-cancerous lesions/conditions in men was found. An association between diabetes mellitus and pre-malignant oral lesions among women has been observed in our study, although the underlying mechanisms are not clear. This needs to be further evaluated in other settings.

[Tobacco-associated lesions of the oral mucosa]

Consumption of tobacco can result not only in a multitude of different general health problems like carcinoma of the lung, ischaemic cardiac diseases, peripheral vascular diseases, stroke, chronic-obstructive pulmonary diseases or peptic ulcers, but also in pathologic lesions of the oral mucosa. Benign oral lesions from smoking or consumption of smokeless tobacco are the so-called smoker's palate and smoker's melanosis. On the other hand, tobacco-associated lesions like oral leukoplakia or oral squamous cell carcinoma are already potentially life-threatening diseases that in general require active treatment. The following review article will present and discuss the typical lesions of the oral mucosa that result from chronic tobacco consumption. The aim of this article is to demonstrate dental health care providers the needs and benefits of tobacco use cessation in a dental setting, especially regarding stomatologic sequelae and consequences. The present article is the first in a series of articles from the Swiss task force "Smoking - Intervention in the private dental office" on the topic "tobacco use and dental medicine".

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.

Increased Risk of Oral Leukoplakia and Cancer Among Mixed Tobacco Users Carrying XRCC1 Variant Haplotypes and Cancer Among Smokers Carrying Two Risk Genotypes: One on Each of Two Loci, GSTM3 and XRCC1 (Codon 280)

An individual's susceptibility to oral precancer and cancer depends not only on tobacco exposure but also on the genotypes/haplotypes at susceptible loci. In this hospital-based case-control study, 310 cancer patients, 197 leukoplakia patients, and 348 controls were studied to determine risk of the disease due to polymorphisms at three sites on XRCC1 and one site on XRCC3. Independently, variant genotypes on these loci did not modulate risk of leukoplakia and cancer except for the XRCC1 (codon 280) risk genotype in exclusive smokeless tobacco users with leukoplakia [odds ratios (OR), 2.4; 95% confidence intervals (CI), 1.0-5.7]. But variant haplotypes, containing one variant allele, on XRCC1 increased the risk of leukoplakia (OR, 1.3; 95% CI, 1.0-1.7). Among stratified samples, mixed tobacco users, carrying variant haplotypes, also had increased risk of both leukoplakia (OR, 2.2; 95% CI, 1.3-3.9) and cancer (OR, 1.9; 95% CI, 1.2-3.1). In a previous study on this population, it was shown that the GSTM3 (A/A) genotype increased the risk of oral leukoplakia and cancer among smokers, which has also been substantiated in this study with expanded sample sizes. The simultaneous presence of two risk genotypes in smokers, one on each of two loci, GSTM3 and XRCC1 (codon 280), increased the risk of cancer (OR, 2.4; 95% CI, 1.0-5.8). Again, smokers carrying two risk genotypes, one on each of two loci, GSTM3 and XRCC1 (codon 399), were also overrepresented in both leukoplakia and cancer populations (P(trend) = 0.02 and 0.04, respectively) but enhancement of risks were not observed; probably due to small sample sizes. Therefore, the presence of variant haplotypes on XRCC1 and two risk genotypes, one on each of two loci, GSTM3 and XRCC1, could be useful to determine the leukoplakias that might progress to cancer in a group of patients.

Tobacco cessation for the dental team: a practical guide part I: background & overview

Dental professionals are strategically placed to be the leaders in tobacco prevention and cessation as they provide preventive and therapeutic services to a basically healthy population on a regular basis. By expanding the dental exam, diagnosis, and treatment to include tobacco cessation, a potentially life saving element of care is added to an established service. In addition periodontal disease and the potential for oral cancer mandate the inclusion of tobacco cessation services into dental care. Though dental professionals are aware of the health issues associated with tobacco use, they often feel ill prepared or uncomfortable presenting patients with a clear cessation message. In this, the first of a two-part article, the purpose is to provide dental professionals with the foundational knowledge necessary to provide effective tobacco cessation as a normal part of patient care.

Dyskeratosis congenita: its connections with oral and maxillofacial surgery

Dyskeratosis congenita is characterised by abnormal pigmentation of skin, dystrophy of nails, and mucosal leukoplakia mainly on the tongue. Bone marrow failure, pulmonary complication, and premalignant leukoplakia of the tongue are serious complications of the disease.