Barriers to early detection and management of oral cancer in the Asia Pacific region

Objective

Oral cancer is amenable to early detection but remains a prominent cause of mortality in the Asia Pacific region. This study aimed to identify barriers to early detection and management of oral cancer in the Asia Pacific region.

Methods

A mixed-methods approach was employed triangulating findings from a survey and focus groups. The survey was conducted among seven representative members of the Asia Pacific Oral Cancer Network (APOCNET) across six countries. Focus groups were conducted to gain deeper insights into the findings of the survey.

Results

The identified barriers were a lack of national cancer control strategies and cancer registries and the limited availability of trained health care professionals. Overcoming these challenges in the Asia Pacific region where resources are scarce will require collaborative partnerships in data collection and novel approaches for continuous professional training including eLearning. Further, to overcome the lack of trained health care professionals, innovative approaches to the management of oral potentially malignant lesions and oral cancer including telemedicine were suggested.

Conclusion

The findings of this study should be taken into account when charting national cancer control plans for oral cancer and will form the basis for future collaborative studies in evaluating effective measures to improve oral cancer detection and management in low- and middle-income countries.

The Response of the Tongue Epithelial on Cigarette Smoke Exposure as a Risk Factor for Oral Cancer Development

OBJECTIVE

 The aim of this study is to analyze the tongue epithelial response to cigarette smoke exposure on a number of macrophages, lymphocytes, plasma cells, and matrix metalloproteinase 9 (MMP-9) expression to determine the risk factor of oral cancer development.

MATERIALS AND METHODS

 Thirty Rattus norvegicus will be exposed to two kinds of cigarette smoke by a smoking pump for 4 and 8 weeks. The tongues were collected to analyze the number of macrophages, lymphocytes, and plasma cells with hematoxylin-eosin. The MMP-9 expression was similarly analyzed with immunohistochemical staining and then compared with the control group.

RESULTS

 The number of macrophages, lymphocytes, and MMP-9 expression was higher in the 8-week cigarette smoke exposure compared to the 4-week cigarette smoke exposure and the control group (p < 0.000). The number of plasma cell did not differ in the 8-week cigarette smoke exposure from that of the control group (p > 0.05). The number of plasma cells in the tongue tissue during the 4-week cigarette smoke exposure was not determined.

CONCLUSION

 Cigarette smoke exposure induces the risk of oral cancer development as a result of an increase in the number of macrophages, lymphocytes, and MMP-9 expression in the tongue epithelial.

Establishing and managing a periodontal biobank for research: the sharing of experience

Periodontal bio-repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad-based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders.

Seropositivity of HPV 16 E6 and E7 and the risk of oral cancer

OBJECTIVES

The objective of the study was to determine the prevalence of HPV seropositivity among patients with oral squamous cell carcinoma (OSCC) and healthy individuals and to correlate the association between HPV 16 seropositivity and risk of OSCC.

MATERIALS AND METHODS

HPV 16 E6 and E7 plasmids were constructed for the production of recombinant protein, which was used as the antigen in ELISA. HPV ELISA was performed on serum samples from 50 healthy individuals and 50 patients with OSCC.

RESULTS

Using the HPV ELISA, 30% (OR = 2.25, 95% CI = 0.85-5.93) and 18% (OR = 1.61, 95% CI = 0.53-4.92) of patients with oral cancer were found to be HPV 16 E6 and E7 seropositive, respectively. Significant association was found between HPV 16 seropositivity and increased risk of OSCC in men, but not in male subjects. A similar trend was observed in non-betel quid chewers.

CONCLUSIONS

Potential associations between HPV 16 E6/E7 seropositivity and oral cancer were revealed in men and non-betel quid chewer subjects, suggesting a possible etiological role of HPV 16 in subgroup of patients with OSCC in Malaysia.

Dysregulation of miR-31 and miR-375 expression is associated with clinical outcomes in oral carcinoma

OBJECTIVES

To identify differentially expressed miRNA between oral squamous cell carcinoma (OSCC) and non-cancer (NC) and to associate these with clinico-pathological parameters.

MATERIALS AND METHODS

miRNA microarray profiling was utilized to obtain the expression profile of miRNAs in four OSCC and four NC samples. The expression of miR-31 and miR-375 was further validated in 26 OSCC and three NC samples using real-time-PCR. The association between miRNA expression and clinico-pathological parameters was tested by univariate and multivariate analyses.

RESULTS

Microarray profiling demonstrated that 15 and four miRNAs were up-regulated and down-regulated, respectively, in OSCC as compared with NC. miR-31 and miR-375 were validated as up- and down-regulated miRNAs, respectively. In univariate analyses, expression of miR-31 was significantly elevated in early stage, tumours with no metastatic nodes and those from the buccal mucosa. By contrast, low miR-375 expression was significantly associated with late stage disease, larger tumour size and the non-cohesive type of pattern of invasion in OSCC. The association between miR-31 expression with tumour staging and site and miR-375 with tumour staging remained significant in multivariate analyses.

CONCLUSIONS

This study has identified 19 miRNAs significantly associated with OSCC, and expressions of miR-31 and miR-375 were significantly related with clinico-pathological parameters suggesting they could be important in driving oral tumourigenesis.

Gene expression in human oral squamous cell carcinoma is influenced by risk factor exposure

Oral squamous cell carcinoma (OSCC) is a world health problem and is associated with exposure to different risk factors. In the west, smoking and alcohol consumption are considered to be the main risk factors whilst in India and southeast Asia, betel quid (BQ) chewing is predominant. In this study, we compared the gene expression patterns of oral cancers associated with BQ chewing to those caused by smoking using Affymetrix microarrays. We found that 281 genes were differentially expressed between OSCC and normal oral mucosa regardless of aetiological factors including MMP1, PLAU, MAGE-D4, GNA12, IFITM3 and NMU. Further, we identified 168 genes that were differentially expressed between the BQ and smoking groups including CXCL-9, TMPRSS2, CA12 and RNF24. The expression of these genes was validated using qPCR using independent tissue samples. The results demonstrate that whilst common genes/pathways contribute to the development of oral cancer, there are also other gene expression changes that are specific to certain risk factors. The findings suggest that different carcinogens activate or inhibit specific pathways during cancer development and progression. These unique gene expression profiles should be taken into consideration when developing biomarkers for future use in prognostic or therapeutic applications.

Human telomerase reverse transcriptase expression in oral carcinogenesis--a preliminary report

Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, is strongly associated with telomerase activity implicated in cellular immortalization and tumorigenesis. In situ detection of hTERT will aid in determining the localization of telomerase positive cells. The aim of this study was to detect hTERT protein expression in multistep oral carcinogenesis using paraffin embedded tissue samples, and to study the relationship of hTERT expression with different histological stages in oral carcinogenesis. Normal (n = 4), hyperplastic (n = 4), dysplastic (n = 4) and neoplastic (n = 10) oral epithelia representing different histological stages in oral carcinogenesis were included in the study. hTERT protein detection was done by immunohistochemistry (IHC) technique. Nuclear staining intensities were noted and the hTERT-labelling index was determined. Dysplastic and neoplastic oral epithelia showed an increased percentage of hTERT positive cells (Grade 4: > 50% positive staining nuclei) with intense staining in the basal, parabasal and superficial layers of the epithelia, unlike normal oral mucosa which showed intense staining only in the basal and parabasal cell layers, which are the normal proliferative progenitor compartments. hTERT protein expression was elevated with the corresponding advancement of the histological stages of oral carcinogenesis, from normal to hyperplasia to dysplasia to carcinoma. There seems to be an upregulation of hTERT protein expression during the progression of oral cancer, therefore, this may indicate the feasibility of IHC detection of hTERT protein in oral carcinogenesis as a potential diagnostic or prognostic marker.

Cultural and dietary risk factors of oral cancer and precancer--a brief overview

This is an update on cultural and dietary risk factors for oral precancer and cancer. It is an overview on ethnic differences (where possible) and socio-cultural risk factors (tobacco/areca nut/betel quid, alcohol use and dietary factors) in relation to oral precancer and cancer. While studies were from Western countries, India and China, this update also attempts to include and highlight some studies conducted in the Asia-Pacific region.

Oral recurrent aphthous ulcers/stomatitis: prevalence in Malaysia and an epidemiological update

One of the objectives of this short communication was to add to the literature on the prevalence of oral recurrent aphthous stomatitis (ORAS). This research is based on a total of 11,697 randomly selected Malaysian subjects with an age range of 25-115 years and a mean age of 44.5 +/- 13.9 years who were examined for oral mucosal lesions (ORAS). The prevalence of ORAS detected during the oral examination (average point prevalence) was found to be 0.5% (64 subjects). ORAS formed 5.7% of all lesions detected during the survey. The average point prevalence of ORAS was highest in the indigenous people of Sabah and Sarawak (1.2%), followed by the Chinese (0.7%), the Malays (0.5%) and the Indians (0.1%). This difference was statistically significant (p < 0.001). A review of the English literature on the prevalence of ORAS revealed different prevalence types used by different researchers, namely average point prevalence (APP), self reported life-time prevalence (SLP) and self reported two-year prevalence (STP). The other objective of this paper was to present the different types of prevalence that have been reported in the literature and to discuss the usefulness of such prevalence types in relation to using epidemiology in deriving certain possible etiological associations.

Clinicopathologic study of odontogenic keratocysts in Singapore and Malaysia

This was a retrospective study of odontogenic keratocysts in people from the Singapore-Malaysian region. The purpose of this study was to present the clinicopathologic features of odontogenic keratocysts in the Oriental population and to compare these data with those from other reported studies. Biopsy records from 1981 to 1992 of 61 cases of odontogenic keratocysts from patients in Malaysia and Singapore showed that 42.6% of patients were female and 57.4% of patients were male. Among patients with cysts, 75.4% were Chinese, 6.6% were Malays, 9.8% were Indians and 8.2% were other ethnic groups. The mean age of these patients was 26.98 +/- 15.38 years with a peak incidence occurring in the second to fourth decades. The location of the lesions was more often in the mandible (65.5%) than the maxilla (31.0%). There was a marked predilection for lesions to occur in the posterior mandible. Histologically, 90.2% of the cysts were lined with a para-keratinized stratified squamous epithelium while only 3.3% of the cysts were lined with orthokeratinized stratified squamous epithelium. Mixed para-keratinized and orthokeratinized epithelial linings were observed in 4 cases (6.5%). The cyst linings were mainly uninflamed (95.1%). Inflammation of the cyst wall was found in 42 cases (68.8%). Twelve (19.7%) cases contained keratin in the lumen. A satellite cyst was observed in only 6 cases (9.8%). In conclusion, most clinical and histological features seen in this study were similar to those found for Caucasians. The only clinical feature that was different was the peak age incidence, that ranged from the second to fourth decades, with an absence of a second peak. Odontogenic keratocysts presenting at the site of the dentigerous cyst were observed in 7 cases (11.5%).

Prevalence of oral precancerous and cancerous lesions in elderly Malaysians

A house to house survey on elderly subjects aged 60 years old and above was undertaken in a large district in Malaysia. A total of 486 subjects in randomly selected Enumeration Blocks were interviewed and examined. The prevalence of oral precancerous lesions was recorded at 3.3%, of which leukoplakia was the most common. When the ethnic distribution of these oral precancerous and cancerous (OPC) lesions was compared, 72% of those inflicted were Indians. Oral cancer was detected in two subjects (0.4%), both of whom were of Indian origin. Among subjects with OPC lesions, 4.2% were smokers, 12.7% were betelquid chewers, 11.8% had indulged in both habits, whilst one subject had not practised any of the oral habits of interest (0.4%). The findings suggest the occurrence of OPC lesions to be related to betelquid chewing.

Oral mucosal lesions associated with betel quid, areca nut and tobacco chewing habits: consensus from a workshop held in Kuala Lumpur, Malaysia, November 25-27, 1996

A variety of betel/areca nut/tobacco habits have been reviewed and categorized because of their possible causal association with oral cancer and various oral precancerous lesions and conditions, and on account of their widespread occurrence in different parts of the world. At a recent workshop in Kuala Lumpur it was recommended that "quid" be defined as "a substance, or mixture of substances, placed in the mouth or chewed and remaining in contact with the mucosa, usually containing one or both of the two basic ingredients, tobacco and/or areca nut, in raw or any manufactured or processed form." Clear delineations on contents of the quid (areca nut quid, tobacco quid, and tobacco and areca nut quid) are recommended as absolute criteria with finer subdivisions to be added if necessary. The betel quid refers to any quid wrapped in betel leaf and is therefore a specific variety of quid. The workshop proposed that quid-related lesions should be categorized conceptually into two categories: first, those that are diffusely outlined and second, those localized at the site where a quid is regularly placed. Additional or expanded criteria and guidelines were proposed to define, describe or identify lesions such as chewer's mucosa, areca nut chewer's lesion, oral submucous fibrosis and other quid-related lesions. A new clinical entity, betel-quid lichenoid lesion, was also proposed to describe an oral lichen planus-like lesion associated with the betel quid habit.

A national epidemiological survey of oral mucosal lesions in Malaysia

The prevalence of oral mucosal lesions in Malaysia was determined by examining a representative sample of 11,707 subjects aged 25 years and above throughout the 14 states over a period of 5 months during 1993/1994. A two-stage stratified random sampling was undertaken. A predetermined number of enumeration blocks, the smallest population unit in the census publication, was selected from each state. With the selected enumeration block, a systematic sample of living quarters was chosen with a random start. The survey instrument included a questionnaire on sociodemographic characteristics and a clinical examination. The clinical examination was carried out by 16 specially trained dental public health officers and the diagnosis calibrated with a final concordance rate of 92%. The age in the sample ranged from 25 to 115 years with a mean of 44.5+/-14.0. The sample comprised 40.2% males and 59.8% females; 55.8% were Malays, 29.4% Chinese, 10.0% Indians and 1.2% other ethnic groups. Oral mucosal lesions were detected in 1131 (9.7%) subjects, 5 (0.04%) had oral cancer, 165 (1.4%) had lesions or conditions that may be precancerous (leukoplakia, erythroplakia, submucous fibrosis and lichen planus) and 187 (1.6%) had betel chewer's mucosa. The prevalence of oral precancer was highest amongst Indians (4.0%) and other Bumiputras (the indigenous people of Sabah and Sarawak) (2.5%) while the lowest prevalence was amongst the Chinese (0.5%).

Training examiners for a national epidemiological survey of oral mucosal lesions

Ensuring the validity and reliability of data collected in epidemiological surveys is an important consideration. The purpose of the present report is to describe a training and calibration programme for 16 examiners taking part in a national survey of oral mucosal lesions and to present an evaluation of the results. The programme included the distribution of a pictorial manual to participants and a series of lectures followed by three diagnostic sessions, two using slides and the last involving patients. At the final session, the trainees classified 88 per cent of 16 patients correctly in comparison with the definitive diagnoses of the trainer, and their sensitivity on recording oral carcinoma, leukoplakia and lichen planus was at least 0.88. However, correctly classifying submucous fibrosis on the basis of slides alone proved problematic. At the conclusion, the diagnostic accuracy of two examiners for all types of lesion remained appreciably lower than the majority. Training strategies for various types of study are discussed. The method reported is considered to represent a model approach to training and calibrating examiners for this type of survey work.

Proliferating cell nuclear antigen (PCNA) and p53 in epithelial dysplasia and squamous cell carcinoma of oral mucosa--a marker for poor tumor differentiation, increasing nuclear atypia and invasiveness?

The immunohistochemical expression of proliferating cell nuclear antigen (PCNA) and p53 was investigated in 9 cases of epithelial dysplasia and 38 cases of squamous cell carcinoma of the oral cavity. The intensity of immunoreactivity for each marker was assessed using a semiquantitative grading system, and was correlated with tumor differentiation, nuclear atypia and the patterns of invasive margins in the underlying connective tissue. PCNA expression, in dysplastic epithelium, was observed in the suprabasal and lower spinous layers; and the labeling grade and intensity of staining increased along with the degree of cellular atypia. In 2 cases of dysplasia, weak positive immunoreactivity for p53 could be seen in a few isolated cells of the basal layer. In squamous cell carcinoma, PCNA expression was correlated with the degree of tumor differentiation and nuclear atypia in well and moderately differentiated carcinoma, but not with the invasive pattern of tumor growth. Immunoreactivity for p53 was positive in 30 cases and showed a distribution pattern very similar to PCNA but with fewer positive cells. Three distinct categories of expression for PCNA and p53 were observed, among them a combination of intense reactivity for both markers was indicative of poor differentiation, higher nuclear atypia and more invasive growth of tumor cells.

Oral pyogenic granuloma (excluding pregnancy tumour)--a clinical analysis of 304 cases

A clinical analysis of 304 cases of pyogenic granuloma (excluding pregnancy tumour) were obtained from the clinical evaluations submitted by clinicians while sending specimens for biopsy. The average age of the patients with pyogenic granuloma was 28.9 years with a peak age incidence in the second decade. More female patients were affected and the lesions present mainly in the Chinese. The majority of the lesions were ulcerated and pedunculated. The lesions had a mean diameter of 10.8 mm with a mean lesion duration of 6.0 months. The gingiva was the prevalent site for these lesions with a greater number being located in the maxilla. The recurrence rate was found to be 14.1%.

An epidemiological survey of oral mucosal lesions among elderly Malaysians

A house to house random survey on elderly subjects was undertaken in the District of Klang in Malaysia. The objective of this study was to investigate the prevalence of oral mucosal lesions (OML) among the elderly in this area. The primary units in the sampling frame were the Enumeration Blocks (EBs) as defined under the population census. All households of the selected EBs were considered as sampling units and members aged 60 and above were considered as respondents. There was a slight preponderance of females, with the Malays comprising the majority of the subjects. Of the 486 respondents, mean aged 69.1 +/- 7.3 yr, 111 had at least one oral mucosal lesion, a prevalence of 22.8%. A total of 145 lesions were detected. The prevalence of OML was highest among Indians and least among the Chinese. The most common finding was tongue lesions, recording a prevalence of 10.7%, followed by oral pigmentation (4.9%) and white lesions (4.3%). Denture related lesions were comparatively low at 2.5%. Two cases of oral cancer if representative would give a relatively high prevalence of 0.4%.

Proliferating cell nuclear antigen (PCNA) expression in oral squamous cell carcinoma - an aid to conventional histological grading?

Proliferating cell nuclear antigen (PCNA) is a well known marker for cell proliferation. It tends to accumulate in the late G1 and S-phase of the cell cycle. A monoclonal antibody (MoAb) against PCNA is now available and it can react with paraffin-embedded specimens. In the present study, PCNA immunohistochemical staining of 36 cases of oral cancer specimens obtained from surgery were investigated. The results showed differing nuclear staining patterns for PCNA in normal, hyperplastic and dysplastic epithelium, early cancer and 3 levels of differentiation for squamous cell carcinoma of the oral cavity. It appears that PCNA can be a useful marker in delineating normal epithelium and hyperplastic epithelium from dysplasia in the oral cavity. The use of PCNA staining may further emphasize the conventional histopathological grading of well-differentiated, moderately-differentiated and poorly-differentiated oral squamous cell carcinoma but is still dependent on basic criteria as observed without immunostaining. PCNA expression for all grades of squamous cell carcinoma are present at the deep, infiltrative margins.

Bullous pemphigoid--management of a patient with oral and skin lesions

A case of bullous pemphigoid with extra-oral and intraoral lesions in a 60-year-old female is reported. Diagnosis is based on histopathology and direct immunofluorescence, and the treatment regime described included oral prescription of prednisolone and topical application of a mixture of fluocinonide ointment and triamcinolone acetonide in Orabase on the oral lesions.

Fibrous lesions of the gingiva: a histopathologic analysis of 204 cases

Two hundred four cases of fibrous lesions of the gingiva were studied histologically for the presence of calcified tissue, the nature of the connective tissue, the type of keratinization, and the degree of epithelial thickness. Initially these lesions were subcategorized into four specific entities, namely fibrous epulis, fibroepithelial polyp, calcifying fibroblastic granuloma, and ossifying fibrous epulis. It was found that 46.5% of the lesions contained calcifications. The connective tissue was represented predominantly by either the collagenous type (50.5%) or the mixed (cellular and collagenous) type (44.6%). It was also found that 36% of the lesions were ulcerated, and, of these, 79.5% were associated with the cellular type of connective tissue and calcifications. In an attempt to subcategorize the fibrous lesions into specific entities, it was found that 32 cases (15.7%) had mixed features. This fact supports the suggestion that these lesions are stages in the spectrum of a single disease process and should collectively be termed fibroblastic gingival lesions. However, it is also suggested that the two terms, namely peripheral fibroma and fibrous epulis with and without ossification, should be retained whereas the usage of other terminologies should be avoided.

Peripheral fibroma/fibrous epulis with and without calcifications. A clinical evaluation of 204 cases in Singapore

Peripheral fibroma/fibrous epulis accounts for the great majority of localised gingival swellings as was substantiated by various reports in the literature. A study was undertaken to investigate the clinical features of a series of 204 localised fibrous gingival swellings received by the Histopathology Laboratory, Department of Oral Surgery, National University of Singapore. The female patients were more affected than the male patients and the lesions occurred predominantly among the Chinese. The lesions were mainly pedunculated and most commonly occurred in anterior maxilla. The recurrence rate was about 10.3%. In conclusion the results obtained in this study were overall in agreement with those of other authors.

Prevalence of oral soft tissue lesions in out-patients at two Malaysian and Thai dental schools

At the Faculties of Dentistry in Chiang Mai, Thailand (CM), and Kuala Lumpur, Malaysia (KL), 234 and 233 consecutive out-patients of mean ages 33.8 and 31.0 yr, respectively, were examined for the presence of oral mucosal lesions. Tobacco in some form was regularly used by 31.7% and 27.5% of the study populations in CM and KL, respectively. Cigarette smoking was the predominant habit. In CM three persons chewed betel quids and nine smoked banana leaf cigars daily. In addition, there were 24 habitual chewers of tea leaves (miang). In KL six persons chewed betel quids daily. In CM and KL three cases each (1.3%) of tobacco-associated leukoplakias were found. In KL an additional idiopathic leukoplakia was registered. One and three cases of betel related lesions were found in CM and KL, respectively. One case of a squamous cell carcinoma was found in a 45-yr-old Indian woman in KL who had been chewing betel with tobacco daily for many years. High prevalence figures were found for lichen planus, 3.8% in CM and 2.1% in KL, and an extremely high one, 48.3%, in CM for episodes of aphthous ulcers experienced during the last 2 yr. Comparatively low prevalence figures were found for herpes labialis. As could be expected melanin pigmentation was prevalent while only low figures were encountered for denture-related lesions and amalgam tattoos.

The social impact of oral and facial pain in an industrial population

The aim of this study is to determine the social impact of oral and facial pain in a sample involving an industrial population. Out of a total of 355 subjects interviewed, nearly one-half claimed to have oral and facial pain in the previous one month prior to the survey. The most common type of pain was that related to hot or cold fluids or sweet things followed by toothache. On the average, the pain lasted for 4.2 days (SD = 4.9) per person in the past one-month. About one in five persons with pain reported that it was severe enough to disrupt sleep. About one in ten persons reporting pain had to take sick leave because of the pain. However, only one in four persons with pain consulted a doctor or dentist. More than one-third tried to cope with the pain and did nothing while the rest tried various means of self-cure. It is therefore postulated that in this population, pain per se is a poor predictor of utilisation of dental services. Further research into pain coping behaviour and how this affects of pattern of utilisation of dental services is indicated in order to formulate a strategy to encourage the habit of seeking prompt dental care by the target population.

Morphological changes in taste buds of the fungiform papillae after a single dose of x-ray irradiation in rats

The qualitative and quantitative changes occurring in the taste buds of the fungiform papillae of male Sprague-Dawley rats (aged 51-125 days old) after x-ray irradiation were studied. A single dose of 2000 Roentgen (R) was delivered and observations were made at 0, 3, 7, 14, 21 and 30 days after x-ray irradiation. The changes in taste bud morphology were interpreted first as degenerative and then as regenerative at various stages of the study. The degenerative process appeared at about the third day and reached a peak at 7 days. Regeneration then began after a further week and the taste buds appeared mature at about 30 days. While the number of fungiform papillae remained constant throughout the study, there was a marked loss of taste buds on these papillae at 7 days. At 14 days, the number of taste buds increased from this low level, and by 30 days the number approached the control values. Initial taste bud loss could be attributed to a direct irradiation damage leading to taste bud cell desquamation combined with a concomitant mitotic inhibition of the stratum germinativum.

Oral lichenoid reactions during antimalarial prophylaxis with sulphadoxine-pyrimethamine combination

The prevalence of clinically observed oral lichenoid reaction in 186 Malay army personnel using Fansidar for 9 weeks was found to be 4.8%. The prevalence was found to be 0.5% in 186 army personnel who had stopped using Fansidar for 2 months and 0% in 143 army personnel (control group) who had not used Fansidar for at least 4 months. The lesion showed a higher prevalence for the gingiva. There was no correlation between cigarette smoking and the occurrence of these lesions in each group.

Association between cigarette smoking and prevalence of oral mucosal lesions among Malaysian army personnel

The association between cigarette smoking and the prevalence of oral mucosal lesions was examined in 495 Malaysian army personnel. No associations between cigarette smoking and recurrent aphthous ulcerations, pre-leukoplakia and frictional keratosis could be obtained in this study. Positive associations were found between cigarette smoking and leukoedema as well as denture stomatitis. There was a negative association between cigarette smoking and the presence of coated tongue.

The cracked tooth syndrome--crown root vertical fracture

A case of an incomplete tooth fracture followed by a complete fracture was presented. The difficulty of diagnosing this condition was discussed as well as the possible histological explanation of the symptoms experienced by the patient. It once again points out to practising dentists, that whilst deep pockets can give rise to severe periodontal pain, intense and excruciating pain should be investigated with the cracked tooth in mind.

Oral lichenoid drug reaction

This is a case report of an oral lichenoid drug reaction of the buccal sulci in a female diabetic patient who was on an anti-hypertensive drug, alpha-methyldopa (Aldomet) and an oral hypoglycaemic drug, chlorpropamide (Diabinese). The clinical features, histological findings and management are presented.

The dental health of factory workers in Pasir Gudang, Johor (Malaysia)

A study on the oral health status of 198 factory workers (in Antara Steel, Pasir Gudang, Johor) was carried out in November 1986. The subjects were predominantly male (94%) and Malay (91%) with an average age of 27.4 years. The prevalence of caries was 87.4% with a mean DMFT of 7.1 + 5.4. There were 3 subjects with full upper, lower dentures and 16 subjects with partial dentures. Two subjects examined needed dentures but were not wearing them. Thirty five (17.7%) of those examined needed urgent extractions, and 8 needed emergency treatment for fillings. Enamel opacities were found in 141 subjects (75.6%) but only 9 were aware of these defects. Dental health was very poor with 72% examined needing scaling. Seventeen (9%) had gross supra and subgingival calculus. There was a total of 107 (54%) smokers and heavy nicotine stains were found in 41 (20.7%), of the population examined. Examination of soft tissues showed 111 (56%) subjects with recurrent aphthous ulcers whilst 15 (7.6%) suffered from herpes labialis. Five subjects (2.5%) suffered from denture stomatitis whilst the prevalence of other soft tissue lesions was very low.