Incidence of symptomatic venous thromboembolism in oncological oral and maxillofacial operations: retrospective analysis.

We retrospectively analysed the incidence of symptomatic venous thromboembolism (VTE) and associated risk factors in operations under general anaesthesia for cancer of the oral cavity. To identify symptoms related to deep venous thrombosis (DVT) and pulmonary embolism (PE), together with associated risk factors, we reviewed medical records of patients operated on in the department of oral and maxillofacial surgery at the Queen Elizabeth Hospital, Birmingham, United Kingdom, between June 2007 and October 2012. All patients were categorised according to their level of risk of VTE. The incidence of VTE was calculated with univariate associations and odds ratios with related 95% confidence intervals, where possible. In total, 233 patients were included, comprising 244 operations (mean (SD) age at operation 60.9 (13) years). Almost all patients (97%) were classified as having the highest risk of VTE. Swelling of an extremity, expectoration of blood, and tightness of the chest were the most common symptoms for suspected cases. An incidence of 0.41% was found for symptomatic VTE; one man developed a PE 2 days after operation. Associations between the analysed factors and symptomatic VTE were not significant. The development of the complication in oncological oral and maxillofacial operations seems to be rare, even in patients with a high risk. We cannot recommend the use of routine thromboprophylaxis, but it could be advocated in patients with obvious serious risk factors.

Enamel pits in hamster molars, formed by a single high fluoride dose, are associated with a perturbation of transitional stage ameloblasts.

Excessive intake of fluoride (F) by young children results in the formation of enamel subsurface porosities and pits, called enamel fluorosis. In this study, we used a single high dose of F administered to hamster pups to determine the stage of ameloblasts most affected by F and whether pit formation was related to F-related sub-ameloblastic cyst formation. Hamster pups received a single subcutaneous injection of either 20 mg or 40 mg NaF/kg body weight, were sacrificed 24 h later, and the number of cysts formed in the first molars were counted. Other pups were sacrificed 8 days after F injection, when the first molars had just erupted, to score for enamel defects. All F-injected pups formed enamel defects in the upper half of the cusps in a dose-dependent way. After injection of 20 mg NaF/kg, an average of 2.5 white spots per molar was found but no pits. At 40 mg NaF/kg, almost 4.5 spots per molar were counted as well as 2 pits per molar. The defects in erupted enamel were located in the upper half of the cusps, sites where cysts had formed at the transition stage of ameloblast differentiation. These results suggest that transitional ameloblasts, located between secretory- and maturation-stage ameloblasts, are most sensitive to the effects of a single high dose of F. F-induced cysts formed earlier at the pre-secretory stage were not correlated to either white spots or enamel pits, suggesting that damaged ameloblasts overlying a F-induced cyst regenerate and continue to form enamel.