Implants in patients with oral manifestations of autoimmune or muco-cutaneous diseases - A systematic review.

BACKGROUND: To give an overview on implant survival rates in patients with oral manifestations of systemic autoimmune (oral Lichen planus (oLp), Pemphigus (Pe)), muco-cutaneous (Epidermolysis bullosa (EB)), autoimmune multisystemic rheumatic diseases (Sjögren's syndrome (SjS), systemic Lupus erythematosus (sLE), or systemic Sclerosis (sSc)). MATERIAL AND METHODS: Systematic literature review (PubMed/Medline, Embase) using MESH and search term combinations, published between 1980 and August 2018 in English language reporting on dental implant-prosthetic rehabilitation of patients with oLp, Pe, EB, SjS, sLE, sSc, study design, age, gender, follow-up period (≥ 12 months), implant survival rate. Implant-related weighed mean values of implant survival rate (wmSR) were calculated. RESULTS: After a mean follow-up period (mfp) of 44.6 months, a wmSR of 98.3 % was calculated from data published for patients with oLp (100 patients with 302 implants). Data of 27 patients (152 implants) with EB revealed wmSR of 98.7 % following mfp of 32.6 months. For 71 patients (272 implants) with SjS, wmSR was 94.2 % following a mfp of 45.2 months, and for 6 patients (44 implants) with sSc, wmSR was 97.7 % after mfp of 37.5 months. One case report on one patient each with Pe (two implants) as well as sLE (6 implants) showed 100 % SR following at least 24 months. CONCLUSIONS: Guidelines regarding implant treatment of patients with oLp, Pe, EB, SjS, sLE or sSc do not exist nor are contraindicating conditions defined. Implant survival rates of patients affected are comparable to those of healthy patients. For implant-prosthetic rehabilitation of patients with Pe and sLE no conclusions can be drawn due to lack of sufficient clinical data. Implant-prosthetic treatment guidelines regarding healthy patients should be strictly followed, but frequent recall is recommended in patients affected with oLp, SjS, EB, SSc, Pe or sLE.

Immunoprofile of the adenomatoid odontogenic tumor.

This study was focused on the immunohistochemical profile of the adenomatoid odontogenic tumor. A Pub/Medline search revealed a number of immunohistochemical studies including cytokeratin profiles, extracellular matrix proteins, Integrins, ameloblast-associated proteins resorption regulators (RANK, RANKL), p53, PCNA, MDM2 protein, cyclin D1, Ki-67, Bcl-2 metallothionein, metalloproteinases, D56 hepatocyte growth factor, c-met, DNA methyltransferase, podoplanin, TGF-ßI, Smad-2/3, Smad-I-5/-8, Smad 4, beta- catenin, calretinin, and clonality. Careful interpretation of the findings indicates that the adenomatoid odontogenic tumor may be more of a hamartomatous than neoplastic nature.

Removal torque evaluation of three different abutment screws for single implant restorations after mechanical cyclic loading.

PURPOSE: The aim of this study was to evaluate the removal torque of three different abutment screws and pull out strength of implant-abutment connection for single implant restorations after mechanical cyclic loading. METHODS: The study was performed in accordance with ISO 14801:2007. Three implant groups (n=15) were used: group A, PW Plus® with flat head screw; group B, PW Plus® with tapered screw; and group C, Conelog® with flat head screw. All groups had the same implant-abutment connection feature: cone with mandatory index. All screws were tightened with manufacturer's recommended torque. Ten specimens in each group underwent cyclic loading (1×106 cycles, 10 Hz, and 250 N). Then, all specimens were un-tightened, measured for the removal torque, and underwent a tensile test. The force that dislodged abutment from implant fixture was recorded. The data were analysed using independent sample t-test, ANOVA and Tukey HSD test. RESULTS: Before cyclic loading, removal torque in groups A, B and C were significantly different (B> A> C, P<.05). After cyclic loading, removal torque in all groups decreased significantly (P<.05). Group C revealed significantly less removal torque than groups A and B (P<.005). Tensile force in all groups significantly increased after cyclic loading (P<.05), group A had significantly less tensile force than groups B and C (P<.005). CONCLUSIONS: Removal torque reduced significantly after cyclic loading. Before cyclic loading, tapered screws maintained more preload than did flat head screws. After cyclic loading, tapered and flat head screws maintained even amounts of preload. The tensile force that dislodged abutment from implant fixture increased immensely after cyclic loading.

Dental implants in patients with oral mucosal diseases - a systematic review.

To reveal dental implants survival rates in patients with oral mucosal diseases: oral lichen planus (OLP), Sjögren's syndrome (SjS), epidermolysis bullosa (EB) and systemic sclerosis (SSc). A systematic literature search using PubMed/Medline and Embase databases, utilising MeSH and search term combinations identified publications on clinical use implant-prosthetic rehabilitation in patients with OLP, SjS, EB, SSc reporting on study design, number, gender and age of patients, follow-up period exceeding 12 months, implant survival rate, published in English between 1980 and May 2015. After a mean observation period (mOP) of 53·9 months (standard deviation [SD] ±18·3), 191 implants in 57 patients with OLP showed a survival rate (SR) of 95·3% (SD ±21·2). For 17 patients with SjS (121 implants, mOP 48·6 ± 28·7 months), 28 patients with EB (165 implants, mOP 38·3 ± 16·9 months) and five patients with SSc (38 implants, mOP 38·3 ± 16·9 months), the respective SR was 91·7 ± 5·97% (SjS), 98·5 ± 2·7% (EB) and 97·4 ± 4·8% (SSc). Heterogeneity of data structure and quality of reporting outcomes did not allow for further comparative data analysis. For implant-prosthetic rehabilitation of patients suffering from OLP, SjS, EB and SSc, no evidence-based treatment guidelines are presently available. However, no strict contraindication for the placement of implants seems to be justified in patients with OLP, SjS, EB nor SSc. Implant survival rates are comparable to those of patients without oral mucosal diseases. Treatment guidelines as for dental implantation in patients with healthy oral mucosa should be followed.

A systematic review of medical interventions for oral submucous fibrosis and future research opportunities.

Oral Diseases (2011) 17 (Suppl. 1), 42-57 Oral submucous fibrosis (OSF) is a chronic, insidious disease caused by areca nut use, and is associated with both significant morbidity (including pain and reduced oral opening) and an increased risk for malignancy. This systematic review explored and updated the current medical (i.e., non-surgical) interventions available for the management of OSF. Of the 27 published medical interventions, there were four randomized controlled trials. The overall quality of these randomized controlled studies was assessed using the GRADE approach and significant limitations that challenged the conclusions were found. However, this review was valuable in terms of identifying opportunities to provide recommendations for future research, in terms of the populations to research, the types of interventions needed, the types of outcomes to be measured, the study designs needed, and the infrastructure required to conduct studies. The next step is to initiate a pathway for a low-cost research plan leading to the development of a brief protocol for future clinical trials in this field, with an emphasis on conducting studies in regions of the world where OSF is prevalent.

Betel quid chewing, oral cancer and other oral mucosal diseases in Vietnam: a review.

BACKGROUND: Betel quid chewing (BQC) in Vietnam is still prevalent, however, no detailed information about its association with oral cancer and pre-cancer are available in the English literature. Respective online searches (PubMed, Medline) were negative. METHODS: Relevant publications in Vietnamese were collected by the authors and translated. Visits to cancer centres and institutes of odontology (Ho Chi Minh City, Hanoi) were made and seminars with respective scientists were held. Field excursions to local markets and interviews with betel quid vendors and individual BQ chewers gave further insights. RESULTS: Generally, BQC is on the decline in Vietnam. 6.7% of the female population still seems to indulge in this habit. In an earlier study, a prevalence of 0.06% of oral cancer was reported. In a study of 1084 cases of oral cancer, the male:female ratio was 1.05:1 (1997). The age group between 60 and 75 years is most often affected by oral cancer. In BQ chewing women, the buccal mucosa (27.9%), tongue (23.1%) and lips (22.4%) are most often affected. Verrucous carcinoma is seen in the age group 70-79 years with women most often being affected (male:female ratio 1:3.4). The most important risk factor for oral cancer in women is BQC compared with men where smoking, alcohol drinking or combined smoking and drinking habits are the most common risk factors. Oral leukoplakia in BQ chewers is observed in 3.8%, oral submucous fibrosis in 13%. CONCLUSIONS: BQC in Vietnam is on the decline. Association between BQC and oral cancer in elderly women is still of importance. Eventually, the BQC habit will vanish and only play a role in socio-ritual contexts.

[Benign epithelial odontogenic tumors]. / Benigne epitheliale odontogene Tumoren.

The group of benign epithelial odontogenic tumors consists of the four member types of the ameloblastoma family (solid/multicystic, extraosseous/peripheral, desmoplastic, unicystic), squamous odontogenic tumors, calcifying odontogenic tumors, adenomatoid odontogenic tumors, and keratocystic odontogenic tumors, the former "keratocysts" that were recently reclassified by the World Health Organization and are now regarded as tumors. The latter are by far the most frequent tumors in this group, followed by solid/multicystic ameloblastoma. Although the etiology of these lesions is still unknown, a close relationship to normal tooth development is obvious, which is partially imitated by some tumors. Despite some similarities to each other, at least in part, the biological behavior of these lesions is quite different, as are treatment modalities. The diagnosis is essentially based on localization (intraosseous vs. extraosseous/peripheral) and histology, whereupon the correlation of histological findings with radiographic morphology may be of additional diagnostic value. Because of the range of variation, immunohistochemical investigations are not helpful in diagnosing a particular case.

[Malignant odontogenic tumors]. / Maligne odontogene Tumoren.

Malignant odontogenic tumors are extremely rare. As with benign odontogenic tumors, malignant epithelial odontogenic tumors or odontogenic carcinomas are distinguished from the even rarer mesenchymal ones, the odontogenic sarcomas. The existence of odontogenic carcinosarcomas is not yet acknowledged by the World Health Organization. Odontogenic carcinomas comprise ameloblastic carcinoma (AmCa), primary intraosseous carcinoma (PIOC), clear cell odontogenic carcinoma, odontogenic ghost cell carcinoma (OGCC), and the special case of metastasizing ameloblastoma. Odontogenic sarcomas consist of ameloblastic fibrosarcoma and ameloblastic fibrodentinosarcoma and fibroodontosarcoma. Whereas metastasizing ameloblastoma can be diagnosed only after having metastasized, all other malignant odontogenic tumors present with atypia, increased cellularity and mitoses, and invasion. Odontogenic sarcomas are regarded as low-grade tumors that rarely metastasize. Odontogenic carcinomas, however, especially AmCa, OGCC, and PIOC, are more aggressive, with a 5-year survival rate of about 70% for AmCa and OGCC and a 3-year survival rate of about 37% for PIOC. Radical surgery, eventually in combination with radiotherapy, is the treatment of choice.

[Benign odontogenic ectomesenchymal tumors]. / Benigne odontogene ektomesenchymale Tumoren.

The group of odontogenic ectomesenchymal tumors consists of odontogenic fibroma (epithelium-rich and epithelium-poor types), odontogenic myxoma, and cementoblastoma. Whereas odontogenic fibromas and cementoblastomas are very rare lesions, odontogenic myxoma is the fourth common odontogenic tumor, preceded only by keratocystic odontogenic tumor, the odontomas, and ameloblastoma. The diagnosis of cementoblastoma rests on its connection to the root of a tooth. The differentiation of odontogenic fibroma and myxoma from other lesions, especially from normal structures such as dental follicles and papillae, may be challenging if the X-ray appearance (localized osteolysis containing a tooth) is not appreciated and subtle histological clues (remainders of inner enamel epithelium at the surface of the lesion, dentin fragments) are not properly recognized. While odontogenic fibromas have almost no tendency for recurrence and are treated by enucleation or local excision, cementoblastomas and especially odontogenic myxomas have a high percentage of recurrence if intralesional procedures are applied. Hence, complete resection with free margins is recommended--at least for larger odontogenic myxomas and, especially, lesions in the maxilla--to prevent further extension to the orbita or base of the skull.

[Benign "mixed" odontogenic tumors]. / Benigne "gemischte" odontogene Tumoren.

Benign "mixed"odontogenic tumors consist of an epithelial and ectomesenchymal tumor component, distinguishing them from pure epithelial and pure ectomesenchymal odontogenic tumors. In addition, they may have the ability to produce dentin, enamel or cementum. Therefore, they can sometimes already be differentiated radiologically from epithelial odontogenic tumors. Some of the mixed odontogenic lesions are regarded as true tumors (ameloblastic fibroma, odontoameloblastoma, dentinogenic ghost cell tumor), while others are assumed to represent hamartomatous lesions (complex and compound odontoma, probably also ameloblastic fibrodentinoma and ameloblastic fibroodontoma). Preceded by keratocystic odontogenic tumor, complex and compound odontomas are the second most common odontogenic tumors, while other members of the "mixed" odontogenic tumor group are far less frequently diagnosed. Odontoameloblastoma and dentinogenic ghost cell tumors are locally aggressive lesions that require total resection. All other lesions of this group are treated by local excision. Since ameloblastic fibrosarcoma may evolve from ameloblastic fibroma, patients with ameloblastic fibroma should remain in long-term follow-up.

[Adenomatoid odontogenic tumor (AOT) of the mandible: a surgical follow-up]. / Chirurgische Verlaufsbeobachtung eines adenomatoid odontogenen Tumors (AOT) im Unterkiefer: Ein Fallbericht.

The AOT is a relative rare benign odontogenic tumor. It most often appears in the canine region of the maxilla and mandible in young patients. Radiolucencies in the region of non-erupted or vital teeth may produce diagnostic problems. The histological diagnosis of AOT is characterised by odontogenic epithelium, ductlike structures, amyloid-like material and calcifying areas. Case report A female patient of eleven years and ten months was referred for surgical exposure of the left mandibular canine by an orthodontist. This tooth was retained and root formation was incomplete. Radiologically, a radiolucency was seen, extending distally from the crown of the tooth towards the root. The deciduous tooth 73 was extracted and the retained left mandibular canine was surgically exposed. Healing was without result and the tooth was moved orthodontically. Two years later the tooth was seen in regular position and occlusion. Vitality tests were positive, distally to the tooth a 1.5[Symbol: see text]mm periodontal pocket was disclosed. A large radiolucency around the root of the tooth was seen. Supposing a cystic lesion a surgical intervention was performed without removal of the tooth. Histopathologically, an AOT was revealed. Conclusions In the sequence of surgical interventions it is highly likely that already at the first operation an AOT was present, however, went unnoticed clinically. The histological diagnosis of an AOT was only revealed after a second operation including tumor removal. In spite of surgical removal of the AOT the involved tooth found its position in the dental arch.

Prevalence of oral Candida species in leprosy patients from Cambodia and Thailand.

BACKGROUND: Leprosy is a chronic bacterial infection which may lead to significant orofacial morbidity. However, reports on the oral mycotic flora of leprosy patients are rare. The aim of the current study was to explore the oral yeast carriage in two groups of leprosy patients. METHODS: 40 Cambodian (seven men, 33 women) and 48 Thai (14 men, 34 women) leprosy patients from Leprosy Rehabilitation Centre Khien Kleang, Phnom Penh, Cambodia and McKean Rehabilitation Center, Chiangmai, Thailand were randomly selected and their demographic data and clinical history were recorded. Tongue and palatal swabs of each patient were collected using sterile Fungi-Quick swabs (Hain Diagnostika, Nehren, Germany) and they were cultured aerobically on Sabouraud's dextrose agar and CHROMAgar (CHROMagar, Paris, France). Yeast were identified by germ tube, chlamydospore production, and assimilation tests (API 20C AUX, Bio-Merieux, Marcy l'Etoile, France) and reconfirmed using APILAB Plus system (Bio-Merieux). RESULTS: Two groups (Cambodian and Thai) had median age of 35 and 64 years. They had been with leprosy for median durations of 17.7 and 38.9 years (P<0.05), respectively. Overall yeast carriage in two cohorts were 80% and 93.75%. Candida albicans had highest carriage rate in either group (65.6%, 44.4%). Candida krusei and C. glabrata existed as second-line colonizers after C. albicans. Candida glabrata carriage was significantly higher in Thai patients (P<0.05). Multispecies carriage was seen in three Cambodian (9.4%) and five Thai (11.5%) patients. CONCLUSIONS: This study indicates high oral yeast carriage in leprosy patients. Candida albicans remains predominant while C. krusei and C. glabrata are second-line oral colonizers. Co-inhabitation of multiple yeast species is also noted in these patients' oral mycotic flora.

Electrostimulating device in the management of xerostomia.

INTRODUCTION: The present study was undertaken to evaluate the safety and effectiveness of a recently developed electrostimulating device mounted on an individualized intra-oral removable appliance. MATERIALS AND METHODS: The device, containing electrodes, a wetness sensor, an electronic circuit and a power source, was tested on patients with xerostomia in a crossover, randomized, sham-controlled, double-blinded, multicenter study. Electrical stimulation and also sham were delivered during 10 min to the oral mucosa, in the mandibular third molar region. Oral dryness was measured by the sensor. As the primary outcome, sensor dryness and xerostomia symptom changes as a result of device wearing were assessed, and compared between active and sham modes. In addition, side-effects were recorded. RESULTS: Electrostimulation resulted in a significant decrease in sensor dryness, leading to a beneficial effect on patients' subjective condition. No significant side-effects were observed.

Prevalence of oral cancer and potentially malignant lesions among shammah users in Yemen.

The purpose of this study was to assess the prevalence of oral precancerous lesions and squamous cell carcinoma (OSCC) in Yemeni users of shammah, a traditional smokeless tobacco habit known in the Arabian Peninsula. The study group comprised 199 male and one female shammah users who were interviewed via a standardised questionnaire and clinically examined in 48 Yemeni villages and cities. Cases with oral leukoplakia (OL) or mucosal burns (MB) were compared with users without any lesion. MB were detected in 31%, of which 46.8% were located on the tongue or floor of the mouth, and OL in 27%, of which 59.2% were located in the same region. In addition, two cases (1%) of apparent OSCC were identified. Statistically significant increased OR (95% CI) of OL were (a) 6.91 (2.66-17.95) for an average duration of the respective shammah application >5min.; (b) 4.90 (1.99-12.08) for a daily frequency of those applications >10; and (c) 4.22 (1.43-12.43) for a daily duration >6h of chewing qat, also a traditional habit in Yemen. Likewise, decreased OR were (a) 0.39 (0.18-0.85) for rinsing the mouth after the shammah application; (b) 0.36 (0.17-0.78) for successful attempts to stop the use in the past; and (c) 0.26 (0.09-0.72) for existing knowledge about the carcinogenicity of shammah that was present in only 19% overall. In conclusion, evidence was shown for a significant association between the prevalence of OL and the daily duration of shammah application in a dose-dependent manner. An appropriate public health program might help to reduce this potential OSCC burden in shammah users.

Herpes zoster in HIV infection with osteonecrosis of the jaw and tooth exfoliation.

BACKGROUND: Herpes zoster (HZ) infection of the trigeminal nerve is associated with complications such as postherpetic neuralgia, facial scarring, loss of hearing ability and conjunctivitis. Until 2005, postherpetic alveolar necrosis and spontaneous tooth exfoliation have been described in 20 cases unrelated to HIV infection. OBJECTIVE: The aim of this study was to describe HIV infection in patients (two women, two men, average age 30 years) who suffered from HZ attacks to their trigeminal nerves. MAIN OUTCOME MEASURES: None of the patients had received antiherpetic medications or antiretroviral therapy. HIV infection was only diagnosed after the development of HZ. Facial scarring with depigmentation and hyperesthesia (postherpetic neuralgia) was diagnosed in all four patients. Oral findings consisted of spontaneous loss of both maxillary or mandibular teeth. Osteonecrosis of varying extent was also found. Treatment consisted of extractions of teeth and administration of antibiotics and analgesics. Healing of alveolar wounds was unremarkable. CONCLUSION: Complications affecting the alveolar bone and teeth seem to be rare in HIV-infected patients.

Unusual foreign metallic object (nail) in the dentition of a skull from the anthropological collection of Rudolf Virchow (Berlin).

Foreign bodies in the dentition of present day patients are frequently diagnosed. They are more rare in mediaeval and anthropological specimens. Rudolf Virchow, the doyen of pathology in Germany formed a huge collection of anthropological specimens in the 19th century. Among these specimens one skull from Tiflis (Tbilisi, Georgia) found its way into the collection of Virchow in 1881. The skull is that of a prisoner of war who died in 1877 due to dysentery. The skull is remarkable in that a metallic nail was adapted around the second right maxillary molar. Both radiological and clinical findings indicate that the nail was adapted to the tooth while the individual was still alive. In particular, erosion of the cortical bone plate in the affected area and osseous healing between the first and second maxillary molar may be taken as proof of adaptation of the nail in vivo. The reasons why the nail was applied, however, are difficult to explain. The authors assume that the nail was applied not by the individual himself. Probably, the nail was adapted as an amulet to protect the individual from injury or death.

[Oral EBV-associated diffuse large B-cell lymphomas in HIV-negative immunocompromised patients]. / Orale Epstein-Barr-Virus-assoziierte diffuse grosszellige B-Zell-Lymphome bei HIV-negativen immunsupprimierten Patienten.

BACKGROUND: Diffuse large B-cell lymphomas (DLBCL) are non-Hodgkin's lymphomas (NHL) and with a prevalence of 30-40% they comprise the most frequent NHL in adults. Although their etiology is still unknown, a virus induction, especially by the Epstein-Barr-virus (EBV), is the subject of discussion. Patients with congenital or acquired immunodeficiency are primarily afflicted. PATIENT 1: A 39-year-old female patient developed an EBV-associated DLBCL of the plasmablastic subtype in the maxillary alveolar ridge in the region of teeth 11 and 21 after 24 years of immunosuppressive therapy with azathioprine due to myasthenia gravis. Clinically the lesion presented as a localized acute necrotizing periodontitis that was resistant to symptomatic therapy. After polychemotherapy the disease is in complete remission until today. PATIENT 2: A 56-year-old male patient developed an EBV-associated DLBCL of immunoblastic variant of the right maxillary edentulous alveolar ridge in the posterior region 7 weeks after heart transplantation and immunosuppressive therapy with azathioprine and cyclosporine A. Clinically, a soft, nonpainful, swelling measuring 1.5x0.5x0.5 cm with a central ulceration was evident. The tumor was excised followed by local radiation therapy. No recurrence was noted during a 15-year-follow-up. DISCUSSION: The presented clinical cases demonstrate the increased risk of occurrence of oral malignant B-cell lymphomas as adverse effects of immunosuppressive therapy. The demonstration of EBV in the tumor cells in both cases underlines the involvement of this virus in the pathogenesis of oral DLBCL arising in the setting of an immunodeficiency as has been shown previously in patients with HIV. CONCLUSIONS: Due to the varying and often nonspecific clinical appearance of oral DLBCL, an early biopsy and work-up by an institute specialized in hematopathology is essential for diagnosis, because these tumors may disseminate in early stages.

(B2) Periodontal diseases and other bacterial infections.

The workshop addressed the following questions with respect to periodontal diseases and bacterial infections seen in HIV infection: (1) What is linear gingival erythema? Is it prevalent only in HIV disease? A crude Delphi technique was used to ascertain whether LGE existed, but a consensus could not be reached. It was agreed that a diagnosis of LGE should be considered only if the lesion persists after removal of plaque in the initial visit. (2) Do periodontal pockets contribute to viremia in HIV infection? At present, the data are not available to answer this question. (3) Do anti-viral drugs reach the sulcular fluid in significant concentrations? No one at the workshop was aware of data that could answer this question. (4) Does concurrent tuberculosis infection modify the oral manifestations of HIV infection? Though analysis of data from the developing countries does suggest an association between tuberculosis and oral candidiasis, more data and multivariate analysis considering immunosuppression as a confounding factor are necessary, for any conclusions to be derived. (5) What pathogens are involved in periodontal diseases in HIV infection? Periodontal disease may be initiated by conventional periodontal pathogens. But the progression and tissue destruction depend upon the presence of typical and atypical micro-organisms, including viruses, their by-products, increased secretion of potentially destructive inflammatory mediators, and overwhelming host response. (6) How can we diagnose the diseases seen in HIV infection? The answer can be obtained only with data from controlled and blinded studies. It is necessary to design collaborative multi-center longitudinal studies. The results obtained from such large sample sizes can contribute eventually to interpretation of the outcome.

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.