Implant failure due to titanium hypersensitivity/allergy?--Report of a case.

Six titanium implants were placed in the mandible between the left and right mental foramen of a 49-year old female patient. The implants were all constructed of the same grade IV titanium. Three types of implants were used, namely LIBB compression implant, cylindrical implant and Brånemark-like implant. These three types of implants were placed as part of a research project, which received approval from the ethics committee. The patient developed a severe reaction to all the implant units, with both clinical and radiological features of complication. The localised tissue reaction was severe enough to warrant removal of all the implants. The surrounding soft tissue was submitted for histological analysis, which revealed a chronic inflammatory response with concomitant fibrosis around all the implants as well as foreign body giant cell reaction around two implants. Following implant removal the patient recuperated well and the soft and hard tissue healed satisfactorily.

Nicotine delivery capabilities of smokeless tobacco products and implications for control of tobacco dependence in South Africa.

OBJECTIVES: Smokeless tobacco (SLT) use is popular among black South African women and children. The study sought to determine the nicotine delivery capability of popular industrialised and traditional SLT brands in South Africa, and to provide information for policy action by regulatory authorities. DESIGN: Laboratory chemical analysis of four industrialised and one traditional SLT products commercially available, using previously published analytical methods. Potential for dependence was inferred from nicotine delivery capabilities determined by the percentage free base nicotine. MEASUREMENTS: Moisture, pH, total nicotine, and percentage free base nicotine. RESULTS: Total nicotine content was between 6-16 mg/g. The pH varied between 7-10 and this correlated with percentage free base nicotine, which ranged between 10-99%. The nicotine delivery capability of the traditional product was lower than that of the industrialised products except for the recently introduced portion bag snus, which had comparable total nicotine but the lowest pH and percentage free base nicotine. The most popular SLT brands showed the highest percentage free base nicotine ever reported for any industrialised SLT or cigarette brands. Small cans contained higher nicotine than the large cans of the same brand tested. Findings from the study support a potential for limited "product graduation" by users. CONCLUSIONS: South African SLT users are mostly exposed to potentially very highly addictive levels of nicotine that may favour tobacco dependence and its consequent health risks. The increasing use of SLT by women of childbearing age support the need for intensified policy action to control its use.

Thermal coagulation caused by different power settings of CO2 laser surgery.

The aim of this clinical research project was to evaluate histopathologically the zone of thermal effects along the cut margin of tissue specimens with the use of CO2 laser surgery regarding laser artifacts and diagnostic biopsy.

The suitability of paraffin-embedded material to predict metastatic potential of oral squamous cell carcinoma.

BACKGROUND: The presence of regional metastasis in oral squamous cell carcinoma (OSCC) is an important prognostic factor. This study was undertaken to identify histological features and biological markers from paraffin-embedded primary OSCC that may predict the presence of regional metastases. MATERIALS AND METHODS: Fifty-three en-bloc primary OSCC resections were divided into two groups, 26 with lymph node metastases and 27 without metastases. The pattern of infiltration, presence of vascular or perineural infiltration and tumour necrosis were evaluated while expression of p53, p21 and Rb were assessed in the two groups. DNA ploidy status was also determined with a flow cytometer. RESULTS: The presence of DNA aneuploidy was found to be the only statistically significant predictor of regional metastases. Seventy-seven per cent of the primary OSCC with lymph node metastases showed DNA aneurploidy. CONCLUSION: DNA flow cytometry obtained from archival material could be used as a parameter to predict regional metastases.

Fhit protein expression in oral epithelium: immunohistochemical evaluation of three antisera.

BACKGROUND: A number of studies have shown that the Fhit tumour suppressor protein is abundantly expressed in normal epithelial cells of human organs and that this expression is lost or reduced in the majority of cancers arising in these epithelial tissues. A variety of antiFhit sera have been used but a systematic comparison of the different antisera has not yet been reported. MATERIALS AND METHODS: We compared the Fhit expression pattern in the epithelium of fibrous epuli, oral lichen planus, oral epithelial dysplasia and oral squamous cell carcinomas (OSCC) using three different Fhit antisera. RESULTS: The antigstFhit sera from two sources gave very similar results for all types of oral lesions except for lichen planus and showed that about 60% of OSCCs have lost Fhit expression. CONCLUSION: Although different staining patterns were found for the three antisera, all three could be used for evaluation of Fhit expression in OSCC.

FHIT RNA and protein expression in oral squamous cell carcinomas.

BACKGROUND: To investigate the possible role of FHIT, a possible tumour suppressor gene, in oral carcinogenesis, we examined 17 oral squamous cell carcinomas (OSCCs) for genetic alterations. MATERIALS AND METHODS: Fresh tissue was obtained during surgery, snap-frozen in liquid nitrogen and stored at -70 degrees C. Nested PCR amplification to examine the integrity of FHIT mRNA was performed on the reverse transcribed complementary DNA obtained from the frozen normal and tumour tissue. Immunohistochemistry was done on formal in-fixed paraffin-embedded tissue protein from the same cases using a polyclonal antiserum against the full length Fhit. RESULTS: Twelve out 17 (71%) OSCCs showed reduced or absent Fhit protein and half of the cases with reduced Fhit protein exhibited aberrant RT-PCR products. CONCLUSION: Immunohistochemical detection of Fhit protein expression in OSCCs is the more sensitive method to determine the status of Fhit in these tumours, in agreement with previous studies of other tumour types.

Epstein-Barr virus strain characterisation in South African patients with nasopharyngeal carcinomas.

UNLABELLED: Epstein-Barr virus (EBV) has been implicated in various diseases, among others, nasopharyngeal carcinoma (NPC). In this study we investigated the frequency and subtype distribution of EBV in 39 NPCs. The presence of EBV was detected by using a nested PCR to amplify the Bam Hl W-fragment of the genome. Two regions were targeted for subtype analysis, namely the EBNA-2A and EBER regions. PCR was used to amplify these regions, and the EBER region was sequenced to detect subtype specificity. The results showed that EBV could be detected in 82% (31/38) of the tumours. In 15 of these, EBNA subtypes could be identified of which 14 were subtype A and one tumour had both subtypes A and B present. The EBER region was amplified in 21 samples. The majority of cases (18/21) demonstrated a mutation profile which consisted of 5 type B and one type A mutations. The consensus type is therefore type B. IN CONCLUSION: a strong association was found between EBV and NPCs in our group of patients and their "consensus" genotype was A/B based on the two genome areas investigated.

Prevalence and pattern of snuff dipping in a rural South African population.

The contradictory results of earlier studies on the role of snuff in the aetiology of oral cancer may be due to the heterogeneous composition of snuff and to regional and cultural differences in its use. The aim of this study was to determine the prevalence and pattern of use of oral snuff in a rural South African adult population, and to report on associated oral lesions. A structured questionnaire was administered by means of face-to-face interviews with a population of 30 randomly selected households (125 adults over the age of 30 years). Of the respondents, 20.8% were active oral snuff-dippers and 80.8% of them had never visited a dentist before. There was no significant difference between the genders of the dippers (P > 0.05). The mean age of dippers was 62.7 years. None of the snuff-dippers chewed or smoked tobacco, but 38.5% used alcohol. Mean dipping period was 21.5 years, for about 2 hours per day and an average of 35 minutes per dip. Of the snuff-dippers, 84.6% place their snuff in the lower labial sulcus and 15.4% in the lower buccal sulcus, 80.8% of the dippers demonstrated keratotic lesions at the site of placement. The clinical severity of the lesions was significantly associated with the brand of snuff used (P < 0.01). The high prevalence of snuff dipping and associated lesion in many of the elderly that had never visited a dentist before highlights the importance of regular screening of this group at risk.

Comparison of bitemarks left in foodstuffs with models of the suspects' dentitions as a means of identifying a perpetrator.

In a recent court case, a comparison was made between an impression of marks left in cheese at a murder scene and a set of study models of one of the suspects. The court was reluctant to accept the validity of the pattern-associated comparison that was used in the identification. This study compared marks made in cheese, butter and cooked potato with study models taken from volunteers. Pattern-associated comparison was the method used. Eighty pair-wise comparisons were made by two odontologists. The examiners correctly identified all the true matches from among the eighty comparisons as well as selecting the dental models for which there were no corresponding silicone impressions. In the absence of identifiable fingerprints or DNA samples, the method can be employed for matching left in foodstuffs to the dentitions of suspects.

Immunohistochemical evaluation of Fhit protein expression in oral squamous cell carcinomas.

The expression of Fhit (fragile histidine triad) protein in oral squamous cell carcinoma (OSCC) and adjacent oral epithelium was evaluated by immunohistochemistry on formalin-fixed paraffin-embedded blocks of 32 cases of OSCC. Rabbit polyclonal anti-GST-Fhit antiserum at 1:600 was used, after antigen enhancement in a microwave pressure cooker, in a saturated lead thiocyanate solution. This antiserum has been shown specifically to detect human Fhit by immunohistochemistry at dilutions up to 1:10,000. The Fhit protein expression was evaluated using both the intensity and extent of staining. Normal stratified squamous epithelium showed strong positivity, especially in the stratum spinosum and areas of keratinisation. Basal and parabasal cells were negative or expressed low levels of Fhit relative to the squamous epithelium. Mild and moderate epithelial dysplasia showed Fhit expression in the superficial layers, while Fhit expression was absent from severely dysplastic lesions. A reduction or loss of Fhit expression was found in 21 (66%) of the OSCC. The alterations in Fhit protein expression in OSCC, and not in normal tissues, are consistent with the proposal that Fhit inactivation plays a role in oral carcinogenesis.

Warthin's tumour is not an Epstein-Barr virus related disease.

BACKGROUND: The histogenesis of Warthin's tumour (WT) is controversial. A possible role for Epstein-Barr virus (EBV) has been suggested. MATERIALS AND METHODS: Twenty formaldehyde-fixed, paraffin-embedded blocks of WT from the parotid gland were examined for the presence of EBV. In situ hybridisation was performed using EBV encoded small nuclear RNAs (EBER1/2) probes labelled with fluorescein isothiocyanate. An EBV-positive P3HR-1 cell line processed to paraffin wax was used as a positive control and a brain section as negative control. RESULTS: EBER1/2 could not be found in the neoplastic epithelial cells in any of the tumours nor in the adjacent normal parotid tissues. Individual positive lymphocytes were present in 7 tumours. CONCLUSIONS: These results indicated that EBV is not involved in the pathogenesis of WT.

Densitometric evaluation of intra-oral radiographic film-processing solution combinations.

In order to determine the effect of seven film processing solutions on the quality of the radiographic image produced on three intra-oral speed group D radiographic films, an aluminium step-wedge was used as a phantom and the films exposed under standardized conditions. Processing was carried out, using each of the seven processing solutions in strict accordance with the manufacturers' recommendations. The processed films were subsequently subjected to densitometric evaluation and the data pertaining to base plus fog, radiographic contrast, density and relative film speed, for each film-processing solution combination, were tabulated. The best combination proved to be that of Flow X-ray film and Kolchem processing solution.