Assessment of the intrasinusidal volume before and after maxillary sinus augmentation using mri - a pilot study of eight patients

PURPOSE

The purpose of this study was to evaluate the suitability, accuracy, and reliability of a non-invasive 3-Tesla magnetic resonance imaging technique (3 T-MRI) for the visualization of maxillary sinus grafts in comparison to conventional, X-ray-based, established standard imaging techniques.

METHODS

A total of eight patients with alveolar bone atrophy who required surgical sinus floor augmentation in the course of dental implantation were included in this pilot study. Alongside pre-operative cone-beam computed tomography (CBCT), 3 T-MRI was performed before and 6 months after sinus floor augmentation. Two investigators measured the maxillary sinus volume preoperatively and after bone augmentation.

RESULTS

In all cases, MRI demonstrated accurately the volumes of the maxillary sinus grafts. Following surgery, the bony structures suitable for an implant placement increased at an average of 4.89 cm3, corresponding with the decrease of the intrasinusidal volumes. In general, interexaminer discrepancies were low and without statistical significance.

CONCLUSION

In this preliminary study, we could demonstrate the feasibility of MRI bone volume measurement as a radiation-free alternative with comparable accuracy to CT/CBCT before procedures like sinus floor augmentation. Nevertheless, costs and artifacts, also present in MRI, have to be taken into account. Larger studies will be necessary to justify the practicability of MRI bone volume evaluation.

Serial assessment of somatic and cardiovascular development in patients with single ventricle undergoing Fontan procedure

BACKGROUND

The palliation of patients with single ventricle (SV) undergoing Fontan procedure led to improved long-term survival but is still limited due to cardiovascular complications. The aim of this study was to describe the somatic and cardiovascular development of Fontan patients until adolescence and to identify determining factors.

METHODS

We retrospectively assessed somatic growth, vascular growth of pulmonary arteries, and cardiac growth of the SV and systemic semilunar valve from 0 to 16 years of age using transthoracic echocardiography. The Doppler inflow pattern of the atrioventricular valve was quantified by E-, A-wave and E/A ratio. All data were converted to z-scores and analyzed using linear mixed effect models to identify associations with age at Fontan procedure, gender, and ventricular morphology.

RESULTS

134 patients undergoing Fontan procedure at a median age of 2.4 (IQR 2.12 to 2.8) years were analyzed. A catch-up of somatic growth after Fontan procedure until school age was found, with lower body height and weight z-scores in male patients and patients with systemic right ventricles. An early time of Fontan procedure was favorable for somatic growth, but not for vascular growth. Cardiac development indicated a decrease of SV end-diastolic diameter z-score until adolescence. Despite a trend towards normalization, E-wave and E/A ratio z-scores were diminished over the entire period.

CONCLUSIONS

There is a catch-up growth of somatic, vascular and cardiac parameters after Fontan procedure, which in our cohort depends on the time of Fontan procedure, ventricular morphology, and gender. Beside other factors, diastolic function of the SV remains altered.

Dental MRI using wireless intraoral coils

Currently, the gold standard for dental imaging is projection radiography or cone-beam computed tomography (CBCT). These methods are fast and cost-efficient, but exhibit poor soft tissue contrast and expose the patient to ionizing radiation (X-rays). The need for an alternative imaging modality e.g. for soft tissue management has stimulated a rising interest in dental magnetic resonance imaging (MRI) which provides superior soft tissue contrast. Compared to X-ray imaging, however, so far the spatial resolution of MRI is lower and the scan time is longer. In this contribution, we describe wireless, inductively-coupled intraoral coils whose local sensitivity enables high resolution MRI of dental soft tissue. In comparison to CBCT, a similar image quality with complementary contrast was obtained ex vivo. In-vivo, a voxel size of the order of 250 ∙ 250 ∙ 500 μm(3) was achieved in 4 min only. Compared to dental MRI acquired with clinical equipment, the quality of the images was superior in the sensitive volume of the coils and is expected to improve the planning of interventions and monitoring thereafter. This method may enable a more accurate dental diagnosis and avoid unnecessary interventions, improving patient welfare and bringing MRI a step closer to becoming a radiation-free alternative for dental imaging.

Evaluation of bone substitute materials: comparison of flat-panel based volume CT to conventional multidetector CT

Over the last decade tissue engineering has emerged as a key factor in bone regeneration within the field of cranio-maxillofacial surgery. Despite this in vivo analysis of tissue-engineered-constructs to monitor bone rehabilitation are difficult to conduct. Novel high-resolving flat-panel based volume CTs (fp-VCT) are increasingly used for imaging bone structures. This study compares the potential value of novel fp-VCT with conventional multidetector CT (MDCT) based on a sheep sinus floor elevation model. Calcium-hydroxyapatite reinforced collagen scaffolds were populated with autologous osteoblasts and implanted into sheep maxillary sinus. After 8, 16 and 24 weeks MDCT and fp-VCT scans were performed to investigate the volume of the augmented area; densities of cancellous and compact bone were assessed as comparative values. fp-VCT imaging resulted in higher spatial resolution, which was advantageous when separating closely related anatomical structures (i.e. trabecular and compact bone, biomaterials). Fp-VCT facilitated imaging of alterations occurring in test specimens over time. fp-VCTs therefore displayed high volume coverage, dynamic imaging potential and superior performance when investigating superfine bone structures and bone remodelling of biomaterials. Thus, fp-VCTs may be a suitable instrument for intraoperative imaging and future in vivo tissue-engineering studies.

Dental MRI: imaging of soft and solid components without ionizing radiation

PURPOSE

To evaluate the ability of conventional and ultra-short or zero echo time MRI for imaging of soft and solid dental components in and ex vivo.

MATERIALS AND METHODS

Turbo spin echo (TSE), ultra-short echo time (UTE), and zero echo time (ZTE) MRI were performed on extracted (human and equine) teeth and in vivo using whole-body and small-bore MR systems at 3 T, 7T, and 9.4T, respectively.

RESULTS

At an isotropic resolution of (600 μm)(3) , strong signal of soft-tissue, e.g., mucosa and nerves with excellent contrast was achieved using TSE at 3T in vivo. No signal, though, was obtained from solid components, e.g., teeth (due to short T(2) ). In contrast, dentin, cementum as well as enamel of extracted teeth were readily depicted using UTE and ZTE at a resolution of ≈ (150 μm)(3) at 7T and 9.4T. In particular, ZTE provided higher signal in enamel.

CONCLUSION

As an alternative to X-ray based methods like cone-beam computed tomography (CT) or conventional CT, the presented results demonstrate the potential of ZTE and UTE MRI as a radiation-free imaging modality, delivering contrast of soft and solid components at the same time.

Stable vertical distraction osteogenesis of highly atrophic mandibles after ablative tumour surgery of the oral cavity--a salvage pathway for mandibular reconstruction prior to oral rehabilitation with dental implants

Mandibular reconstruction is still a challenge for surgeons. Distraction osteogenesis (DO) might contribute in certain instances to solve this problem. A principal advantage of DO is the expansion of the surrounding soft tissues that accompanies the bony regeneration. In addition there is no donor site morbidity when compared with reconstruction by autologous bone grafting. However its application may be limited by the thinness of the mandible and the attendant fracture risk. This article describes a technique that combines stable internal fixation with vertical distraction of the alveolar ridge in six patients with critical mandibular thickness after ablative surgery for cancer of the oral cavity. Prior to implant insertion for further prosthodontic restoration stable vertical mandibular distraction produced an additional 11-20mm. Improvement of the surrounding soft tissues, especially intraorally was achieved and dental implants were inserted after bony consolidation. This method can be a useful salvage technique for the augmentation of the atrophic mandible in patients who are not able or willing to undergo the risks and disadvantages of established methods such as free autologous bone transfer or microsurgical techniques.

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.

The 'Skull from Bangkok': a skull of a betel quid chewer in the anthropological collection of Rudolf Virchow (Berlin)

This report describes the 'Skull from Bangkok', collected by Rudolf Virchow (Berlin, Germany) in the late 19th century. The skull is part of an extensive anthropological collection of skeletons and skulls from all over the world. The skull was probably brought to Berlin during the years 1882-1883. An inscription on the frontal bone gives the name of the skull: 'Skull from Bangkok'. The few remaining teeth of the maxilla show brown black stains because of betel quid chewing. In the collection, there is an extensive number of skulls from South- and Southeast Asia with similar betel stains. Virchow himself was aware of this habit and has described some of the skulls in detail often mentioning the black stains because of betel quid chewing. The Skull from Bangkok is a proof that betel quid chewing was prevalent in Siam of the late 19th century.

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.

Incidence of oral, pharyngeal, and laryngeal squamous cell carcinomas among 1515 patients after liver transplantation

The purpose of this study was to evaluate the incidence and basic characteristics of oral, pharyngeal, and laryngeal squamous cell carcinomas (OPLC) in a single-centre series of liver transplantations (LT). The medical records of 1515 LT cases with a median follow-up of 6 years were analysed retrospectively for incident cases of OPLC. Incidence rates for the oral cavity and pharynx (ICD-9: 141-149), and larynx (ICD-9: 161) were assessed separately. OPLC cases and non-cases were evaluated with regard to end-stage alcoholic liver disease (ALD) as LT indication, smoking, and immunosuppression. The cumulative incidence of 13 cases with OPLC was 0.86% in total (n=1515). For 11 cases of OPLC in 307 patients with LT for ALD, it was 3.58%. The estimates for the annual incidence of OPLC (ICD-9: 141-149) were 121.79 for females and 111.65 for males (/100.000 patient-years). For OPLC (ICD-9: 161), the estimate was 37.21 for males, respectively (no female cases). ALD (84.6%) and pre-LT smoking (92.3%) were significantly overrepresented in OPLC cases (p<0.001). Age and gender distribution were comparable to non-cases. The 5-year survival rate after OPLC was 41.5%. OPLC were demonstrated as a late-onset complication of LT with poor prognosis. The impact of pre-, post-LT smoking, and, in particular, ALD as a confounder of OPLC deserves further investigation.

Oral Candida species and betel quid-associated oral lesions in Padaung women of Northern Thailand

Purpose of the present investigation was to study the association between the betel quid chewing (BQC) habits, the oral yeast flora and oral lesions in female Padaung of northern Thailand. Oral swabs were taken from the tongue and palate of 50 Padaung women with and 50 control individuals without BQC habit. The spectrum of oral Candida species in both groups was determined microbiologically. In addition, oral mucosal lesions were registered in both groups. Mean age of BQ chewers was 35.4 years, of non-chewers was 19.2 years. Candida parapsilosis was the most common Candida spp. isolated both in BQ chewers (46%) and non-chewers (44%). Candida albicans was revealed in 24% of BQ chewers and 18% of non-chewers. There was no significant difference in carriage of Candida spp. isolated between both groups. Forty-four per cent of BQ chewers revealed betel chewers mucosa, 10% showed leukoedema. Isolated populations such as the Padaung may reveal different patterns of candidal flora, in this case a predominance of Candida parapsilosis.

[Occurrence of epithelium in the soft tissues associated with routine surgical removal of 150 mandibular third molars]

BACKGROUND

The aim of the study was to classify epithelial structures (ES) and to determine the prevalence of cysts associated with mandibular third molars (M(3)).

MATERIAL AND METHOD

Sections of HE-stained soft tissue specimens and panoramic radiographs of 150 consecutive patients undergoing surgical removal of M(3) were evaluated. ES were classified as islands and/or strands of odontogenic epithelium (OE), reduced enamel epithelium (REE), stratified cyst epithelium (SCE), oral mucosa (OM), and pocket epithelium (PE). The diagnostic criteria were defined as a pericoronal translucency >2.5 mm and SCE for dentigerous cysts (DC) and a distal translucency >2.5 mm, SCE, and inflammation for inflammatory paradental cysts (IPC).

RESULTS

Median age was 24.4 years: 23.0 years for 86 (57.3%) female patients and 25.7 years for 64 (42.7%) male patients (p=0.017). ES were found in 95.3%, classified as OE in 53.3%, REE in 34.7%, SCE in 28%, OM in 30.7%, and PE in 10.7%. Both REE and SCE were found in 6%. The total number of cases with REE and/or SCE was 56.7%. Median age of cases with SCE was 28.7 years compared to 20.7 years in cases with REE (p<0.001). Pericoronal translucencies were found in four M(3), of which three were associated with SCE. Distal translucencies were found in 47 M(3), of which 15 were associated with SCE and inflammation. The prevalence was 2% for DC and 10% for IPC.

CONCLUSIONS

A differentiated application of histological and radiological criteria enables the prevalence of cystic lesions to be more accurately determined than does the use of one criterion alone.

The sensitivity and specificity of the OralCDx technique: evaluation of 103 cases

In this study, we compared 103 OralCDx results with the histological findings of 96 clinical sites in 80 patients (33 females; 64.3+/-13.7 years and 47 males; 53.2+/-11.5 years). The histological findings were classified as follows: compatible with oral leukoplakia (OL; n = 60) or oral lichen planus (OLP; n = 17), both without dysplasia; dysplasia in OL or OLP (n = 9); and oral squamous cell carcinoma (OSCC; n = 17). There were seven (6.8%) specimens with an inadequate cell count. Overall, the sensitivity of the OralCDx technique to detect dysplasia and OSCC was 92.3% (95% CI: 74.9-99.1%), and the specificity was 94.3% (95% CI: 86.0-98.4%). The positive likelihood ratio (LR+) was 16.2 (95% CI: 6.2-42.1) and the negative likelihood ratio (LR-) was 0.08 (95% CI: 0.02-0.31). In conclusion, these figures are in agreement with previously published data and support the use of OralCDx as a screening tool of oral lesions, but further trials are still necessary.

Clinical risk factors of oral leukoplakia in a representative sample of the US population

Studies on the risk factors of oral leukoplakia (OL) are relatively scarce. The objectives of this paper are to assess the clinical risk factors of OL in a representative sample of the US population. Data from the oral mucosal tissue assessment and some other covariates of 15,811 participants in the US National Health and Nutrition Examination Survey (NHANES III) were included. The clinical definition of OL was applied according to the WHO criteria. Tobacco smoking was found as the strongest independent risk factor. The OR were 3.00 (0.77-11.8) for < or =10 cigarettes/day up to 6.01 (2.4-15.0) for >20 cigarettes/day. Diabetes, age and socio-economic status were found as independent predictors of OL. Alcohol consumption, race/ethnicity, years of education and BMI showed no independent association with OL. Females with a history of estrogen use were less likely to have OL with an OR of 0.34 (0.11-1.07). In conclusion, the role of diabetes and estrogen in the pathogenesis of OL should be further investigated.

Hair artefacts in the head and neck region

Three cases illustrating hair artefacts in conventional and panoramic radiography are reported. Hairstyles may create a considerable range of radiopaque patterns, including simple representation of synthetic hair braid extensions or findings that seem inexplicable without thorough reconstruction of the imaging situation. It may be concluded that hair artefacts should be considered in all questionable opacities of the head and neck region.

Low prevalence of oral leukoplakia in a representative sample of the US population

Recent studies reported a tendency towards a lower prevalence of oral leukoplakia (OL), compared with the past. To assess the prevalence of OL in a representative sample of the US population, data from the oral mucosal tissue assessment and some other covariates of 16128 participants in the US National Health and Nutrition Examination Survey (NHANES III) were included. The clinical definition of OL was applied according to the WHO criteria. The weighted prevalence estimates of OL were 0.66+/-0.14% in males, 0.21+/-0.05% in females and 0.42+/-0.08% in total. The age peaks were at 40-49 years in males and at >or=70 years in females. The prevalence estimates were 0.37% for homogeneous OL and 0.06% for non-homogeneous OL. Gingiva (38.8%) and buccal mucosa (30.9%) were the most frequent locations. Compared to previous studies in the USA, a substantial decline of the prevalence of OL was shown.

Is there a natural limit of the transformation rate of oral leukoplakia?

Recent reviews described a cumulative risk of 0-38% of oral leukoplakias (OL) to transform into oral squamous cell carcinoma (OSCC). The annual transformation rate (ATR) of OL into OSCC amounted up to 6.3%. To elucidate epidemiological consequences of varying ATR. Variations of the prevalence (1-2%) and ATR (0.5-4%) of OL were used to compute the proportional incidences of OSCC developing in OL. These were compared to the actual incidences of OSCC excerpted from European cancer registries. A ratio <50% of predicted to actual incidence overall indicated a plausible ATR. With an ATR>or=3%, the predicted incidences of OSCC would exceed the reported incidences in all countries. With an ATR<or=1%, the ratio of OSCC developed in OL to OSCC overall would be always lower than 50%. Based on present data, it was concluded that the ATR of OL into OSCC should not exceed 1%.

[Detection of TP53-mutations in brush biopsies from oral leukoplakias]

OBJECTIVE

The aim of this study was to determine the prevalence of mutations of the tumour suppressor gene TP53 in oral leukoplakias.

MATERIAL AND METHOD

Brush biopsy specimens of 43 oral leukoplakias, 26 oral squamous cell carcinomas (OSCC) for reference, and the oral mucosa of 4 clinically normal volunteers were collected. DNA of the critical exons 5-8 was analysed by temperature gradient gel electrophoresis (TGGE).

RESULTS

The prevalence of mutations was 57.7% in OSCC, 39.5% in leukoplakias and 0% in controls. The highest frequency of mutations was found in exon 5 (46.2%) in OSCC and in exon 6 (23.3%) in leukoplakia. More than one mutation was detected in 26.9% of OSCC and 7% of leukoplakia specimens. At least one mutation was found in 37.5% of T1 OSCC and 100% of T4 OSCC specimens and in 37.1% of the L1 leukoplakia and 100% of L3 leukoplakia specimens.

CONCLUSIONS

TP53 mutations could be a useful prognostic indicator in precancerous oral lesions. Although the brush biopsy technique appears simple clinically, further investigations are necessary to specify the implications of genetic analysis.

Betel quid-associated oral lesions and oral Candida species in a female Cambodian cohort

BACKGROUND

Betel quid chewing (BQC) is still prevalent among elderly Cambodian women and is associated with a wide variety of oral mucosal lesions. BQC has also been associated with a reduced rate of dental caries and changes in the oral microbiological flora.

METHODS

Since no studies were available on the impact of BQC on the oral carriage of Candida species, in this study oral swabs (Fungiquick, Hain Diagnostika, Germany) were taken from the tongue and palate of 48 Cambodian women with BQC habit (study group) and 13 control subjects without BQC habit (control group) to determine the spectrum of Candida species in these two groups. In addition, we investigated lesions of the oral mucosa likely to be associated with BQC habit in both study and control groups.

RESULTS

The median duration of BQC was 10 years (range 10 months-30 years). The following oral lesions were found in the study group: betel chewer's mucosa (85.4%), oral leukoplakia (8.3%), leukoedema (37.5%) and oral lichen planus (4.2%). Oral candidiasis was seen neither in BQ-chewers nor in controls. Candida spp. were found in 70.8% of the cases (controls 69.2%). Whilst C. albicans was isolated from 27.1% of the study cohort, C. tropicalis was the second most common isolate. One control case was colonised by C. dubliniensis--the first report of this organism from a Cambodian population. There was no significant difference in the candidal carriage rate or the Candida species isolated between the study and the control group.

CONCLUSIONS

Mycological findings from the present study do not indicate that BQC has a significant effect on oral colonisation by Candida species.

Oral manifestations in 101 Cambodians with HIV and AIDS

BACKGROUND

The HIV/AIDS epidemic in Cambodia has become a major problem in the last 7-8 years, mainly because in this formerly war-stricken country the socioeconomic situation is only slowly improving. Since only very few studies have been published to date on the oral health status of Cambodian HIV/AIDS patients, it was the purpose of the present investigation to study oral manifestations in Cambodian patients with HIV disease.

METHODS

One hundred one Cambodian patients with HIV infection or AIDS were examined for the presence of oral manifestations in one medical center in Phomh Penh, Cambodia.

RESULTS

Sixty-three men and 38 women with a median age of 32 years were examined (age range 7.5-63.5 years). Of these patients, 42.6% were smokers, 46.5% of men were heavy drinkers and 90.5% of men were promiscuous compared with 5.3% of women. The most frequent AIDS-defining diseases were wasting syndrome (54.5%), Pneumocystis carinii pneumonia (PcP) (19.8%) and tuberculosis (18.8%). Puritic papular eruption, a common cutaneous manifestation in HIV-infected patients, was seen in 17.8% of patients. Candida-associated infections of the oral cavity were most common. Among the patients, 52.5% revealed pseudomembranous candidiasis and 35.6% had bilateral hairy leukoplakia. Only 10% of patients had no oral lesions. Also common were necrotising ulcerative gingivo-periodontal diseases (27.7%).

CONCLUSION

The general health status of 101 Cambodian patients with HIV infection and AIDS was poor, and they demonstrated a large number of oral manifestations. Antiretroviral therapy is presently not available and only a fraction of patients receives antimycotic treatment (25.7%). HIV infection and the AIDS epidemic in Cambodia have become a serious problem and patients urgently need adequate diagnosis and antiretroviral therapies.

Thai dental students' knowledge of the betel quid chewing habit in Thailand

385 questionnaires submitted by volunteer Thai dental students on the betel quid chewing habit in Thailand were evaluated. Questions related to the composition of the betel quid, general and oral effects as well as sociological aspects. Only 62.6% considered the habit as typical for Thailand. Knowledge about the composition of the betel quid showed that 30% of the students were poorly informed. Only 58.4% thought slaked lime to be part of the quid. Similar results were obtained for some of the questions relating to physiological and oral effects and the percentage of "do not know" answers was about 30%. It was widely accepted that betel quid chewing is more common in the provinces (83.6%) and that it is a habit of older people (92.2%); particularly women (70.7%). 71.2% of the students did not know where to buy a betel quid. The decline of the habit was monitored by the fact that 96.1% of the students' parents did not indulge in chewing the betel quid compared to 38.7% of grandparents who did. 70% of the students were convinced that the habit will totally disappear. The knowledge of the betel quid chewing habit of Thai dental students indicated a number of deficits showing that these do not come in close contact with this habit anymore in their families or societies. Since elderly people still indulge in chewing betel quid, dental education still has to focus on oral and general effects and side-effects such as oral precancer, oral cancer and oral submucous fibrosis.

[Oral leukoplakia in manifest squamous epithelial carcinoma. A clinical prospective study of 101 patients]

OBJECTIVE

The Uppsala-definition of leukoplakia has recently redefined oral leukoplakia. Based on this definition, the aim of our study was to reevaluate the prevalence of oral leukoplakia in patients with histologically proven primary oral cancer.

DESIGN

A total of 101 in-patients in four tumor centers in Berlin were interviewed and clinically examined just prior to surgery of an oral squamous cell carcinoma (OSCC).

RESULTS

The prevalence of leukoplakia immediately adjacent to the carcinoma was 15.8%. Additional leukoplakias without relation to the carcinoma were found in 4% of the patients. There were no significant differences in age- or sex-distribution, history of tobacco habits or diet between patients with or without leukoplakia. T1 carcinomas were found in 62.5% of patients with, and 24.4% of patients without associated leukoplakia, whereas a balanced distribution was found for the pre-operative staging of the tumor.

CONCLUSIONS

The prevalence of oral leukoplakia in patients with OSCC was low, compared to retrospective studies. The presence or absence of leukoplakia indicated no influence on the prognosis of the tumor, except of tumor size. The results emphasize that most OSCC develop from healthy appearing oral mucosa.

Khmer dental and medical students' knowledge about the betel quid chewing habit in Cambodia

95 of 144 questionnaires submitted by volunteer Khmer medical and dental students on the betel quid chewing habit in Cambodia were evaluated (58 medical, 37 dental). Questions related to the composition of the betel quid, the physiological and oral effects as well as traditional and sociological aspects. Statistical tests showed that there were differences between dental and medical students, particularly relating to the knowledge about oral effects. While 81.1% of dental students knew that betel quid chewing causes oral cancer, only 31.0% of the medical students were adequately informed. Similarly, 51.4% of the dental students knew about the relation between betel quid chewing and submucous fibrosis compared to 8.6% of the medical students (P < 0.001). In contrast, only 18.9% of the dental students thought that betel quid chewing strengthens the gum, while 56.9% of the medical students believed that betel quid chewing would have this effect (P < 0.001). The answers also showed that students do not indulge in the betel quid habit. The decline of the betel quid chewing habit was also indicated by the fact that while 5.3% of students had parents chewing betel quid, in contrast 40% of students reported grandparents with this habit. There are deficiencies of knowledge about the most important effects of betel quid chewing, particularly in medical students. Since both medical and dental students will in their future professional life have an enormous impact on health and health education, it seems justified that the dental and medical curricula should focus on these traditional habits. Proper health education starting in the dental and medical school is warranted in Cambodia and probably also in other South and Southeast Asian countries where the betel quid chewing habit is prevalent so as ultimately to improve public knowledge on the oral and other effects of this habit.

Betel chewer's mucosa in elderly Cambodian women

A total of 102 rural Cambodian women with a mean age of 60 +/- 8.5 years (range 39 to 80 years) who chewed betel quid were examined for oral mucosal lesions, in particular betel chewer's mucosa. The average duration of betel quid chewing was 15.5 +/- 12.8 years. The average number of daily betel quids was 5.4 +/- 2.9. Forty women (39.2%) used betel quids overnight. Thirty-eight (37.3%) did not show any oral mucosal lesion. Sixty-two (60.8%) showed betel chewer's mucosa. Homogeneous leukoplakia was found in three women (2.9%). Out of 130 sites affected by chewer's mucosa, the buccal mucosa was the most frequently involed (n = 68). In thirty-two subjects (31.4%) more than one location was affected. The presence of a lesion was significantly associated with the duration of the habit (P < 0.01) and the number of betel quids per day (P < 0.001). Betel chewing seems to be prevalent in elderly Cambodian women, while younger people do not seem to have taken up this habit. The risk for oral cancer in the Cambodian population is presently unknown.