Tunc Kutoglu

The position of the mandibular canal and histologic feature of the inferior alveolar nerve

The inferior alveolar nerve is the one of the large branches of the mandibular division of the trigeminal nerve. It is vulnerable during surgical procedures of the mandible. Despite its importance, no anatomical and histological examination has been conducted to provide a detailed cross‐sectional morphology of the mandibular canal according to dental status. Therefore, the present study aimed to identify the position of the mandibular canal through direct measurement and to determine the branches of the inferior alveolar nerve through histologic examination. The area between the anterior margin of the third molar and the anterior margin of the second premolar of dentulous, partially dentulous, and edentulous hemimandible specimens (n = 49) from 26 human cadavers was serially sectioned into seven segments, and specific distances were measured using digital calipers. Following this, 5‐μm cross‐sections were prepared along the mandibular canal and mental foramen, and examined by fluorescence microscopy. The mandibular canal was located at a mean distance of 10.52 mm above the inferior margin of the mandible. The mean maximum diameters of the mandibular canal, inferior alveolar nerve, inferior alveolar artery, and inferior alveolar vein were 2.52, 1.84, 0.42, and 0.58 mm, respectively. This study found that the inferior alveolar nerve often gives rise to several branches at each level (range 0–3). To minimize the risk of injury, knowledge of the small branches of the nerve and of the detailed findings regarding the position of the mandibular canal reported here should be considered when planning mandibular surgery, especially during implant placement. Clin. Anat. 23:34–42, 2010.

Effect of formaldehyde inhalation on rat livers: a light and electron microscopic study.

It is well known that formaldehyde (FA) is cytotoxic and potentially carcinogenic. Although the individual effects of this reactant on cells has been investigated, the cytotoxicity exerted by the coexistence of FA is poorly understood. The aim of this study was to investigate the effects of FA on the liver in rats, by light and electron microscopic level. We used 18 Wistar albino rats divided into three groups, exposed to 0 (control), 19.7 ppm FA gas for a total of 4 weeks, 8 h/day, 5 days a week (subacute) and 20.3 parts per million (ppm) FA gas for a total of 13 weeks, 8 h/day, 5 days a week (subchronic). After the completion of the exposure period, they were sacrificed by decapitation and their liver tissue samples were taken in order to be processed for light and electron microscopic studies. Light microscopic evaluation of liver tissue samples of FA-exposed rats revealed enlarged sinusoids filled with blood and mononuclear cell infiltration in the portal areas and around the central veins. In addition, some of the hepatocytes showed loss of cytoplasm, and some had a hyperchromatic nucleus. The cells of FA-exposed livers, on the other hand, showed an electron-lucent ground-cytoplasm and a hypertrophy of the smooth-surfaced endoplasmic reticulum. In conclusion, we observed that exposure FA caused diverse histopathological changes indicating the destruction in the liver tissue and this destruction has direct relationship with the length of the exposure period.