Pacinian neuroma in adipose herniation of the buccal mucosa

An interesting case of a trauma-induced tender mass of the buccal mucosa in a 45-year-old man was presented. Following surgery, the patient was relieved from pain. Microscopically, the mature adipose tissue is unique in that it contained a single enlarged Pacinian corpuscle near the deep margin. This is the hitherto undescribed intraoral lesion of Pacinian neuroma in the herniated buccal fat pad.     

Relationship between large tubules and dentin caries in human deciduous tooth

The purpose of this study was to elucidate the relationship between large tubules and dentin caries by using human deciduous incisors that showed various levels of attrition but no macroscopical lesions resulting from caries. The teeth were cut longitudinally in the mesio-distal direction and the exposed surfaces observed with a high-resolution field emission scanning electron microscope. The inside of each large tubule showed dense collagen fibers running parallel to its long axis and small spherical bodies of aggregated crystals, but no marked attrition. In teeth where attrition had exposed dentin at the incisal edge, oral bacteria had infiltrated the large tubules. Furthermore, in teeth with advanced attrition, it was difficult to distinguish between the large tubules and the surrounding dentin matrix, and numerous bacteria were observed in both areas. These findings support the hypothesis that large tubules play a role in the pathway of caries formation in coronal dentin when incisal dentin is exposed by attrition. This suggests that early treatment of exposed dentin surfaces might be effective in preventing dental caries.     

Keratocystic odontogenic tumor: a retrospective study of 183 cases

In 2005, the WHO Working Group considered odontogenic keratocyst (OKC) to be a tumor and recommended the term keratocystic odontogenic tumor (KCOT), separating the lesion from the orthokeratinizing variant, which is now considered an odontogenic cyst. We analyzed the clinicopathological features of KCOTs encountered over a period of 28 years at Meikai University Hospital. The diagnosis was confirmed by reevaluation of hematoxylin and eosin-stained slides on the basis of the 2005 WHO Classification. Clinical history was also taken into consideration. A total of 183 KCOTs were found, and the two genders were affected almost evenly (51.3% male; 48.7% female; male to female ratio 1.05 to 1). Patient age at the time of diagnosis ranged from 6 to 78 years, with a peak in the third decade of life (mean age: 32.8 years). The mandible was the site of occurrence of 70.5% of tumors; 16.4% occurred in the maxilla and 13.1% in both. Association with the nevoid basal cell carcinoma syndrome (NBCCS) was found in 6.0% of all tumors, and recurrence was found in 13.1% of patients. We found that tumors that initially appeared in the maxilla alone had a higher recurrence rate than those that first appeared in the mandible alone. Pathological examination of KCOT is important to avoid misdiagnosis and provide appropriate treatment and follow-up.     

Three-dimensional analysis of pulp chambers in maxillary second deciduous molars

OBJECTIVE: The purpose of this study was to clarify the positional relationship between the crown contour and the pulp chamber using micro-CT system for restorations of maxillary second deciduous molar. METHODS: Five maxillary second deciduous molar teeth each from the deciduous dentition and the mixed dentition periods were used. The positional relationship between the crown contour and pulp chamber was three-dimensionally observed by micro-CT. In addition, the thickness of the dentin at each of the pulp horns and the volume ratio of the pulp chamber against the whole crown were measured. RESULTS: In relationship to the crown contour and the pulp chamber, the pulp horn of the mesiobuccal cusp showed greatest protrusion and eminent swelling of its mesial wall in both the deciduous dentition and the mixed dentition periods. Furthermore, the pulp chamber was shifted to the mesial side. The volume ratio of the pulp chamber to the whole crown, the ratio in the mixed dentition period showed to be significantly smaller than in the deciduous dentition period. The dentin thickness at the mesiobuccal pulp horn was the thinest. CONCLUSIONS: These results suggest that in preparation of cavities in maxillary second deciduous molars, care is necessary not to expose of the mesiobuccal pulp horn. Especially, the mesial wall of the mesiobuccal pulp horn should be noted.     

Electrochemical properties of a gold electrode modified with a mixed monolayer

The electrochemical properties of a gold electrode modified with a mixed thiol monolayer containing both a polar and a non-polar head group have been investigated in aqueous Fe(CN)^4?₆, flavin adenine dinucleotide (FAD) and ubiquinone-0 (2,3-dimethoxy-5-methyl-1,4-benzoquinone, UQ₀) solutions. The cyclic voltammetric current—potential (i — E) response of Fe(CN)^4?₆ was found to be affected considerably by the polarity of the head group contained in the mixed monolayer assembly, as compared with those of FAD and UQ₀. It was also found that in the cases of UQ₀ and FAD the i — E responses for the modified electrode were affected by their own molecular size rather than the polarity of the mixed monolayer head group. Furthermore, compared with Fe(CN)^4?₆ ion, these biologically related molecules are able to permeate readily into the well-organized and hydrophobic alkyl chains of the monolayer assembly. The voltammetric profile of UQ₀ was improved by the modification of aminoethanethiol, as compared with those of bare gold and the electrode modified with other polar thiols. Further, two different permeation paths of the electrode species into the mixed monolayer are suggested from the variation of the i — E response with the cycle of the potential scan.     

Experimental device for detecting laryngeal movement during swallowing

It has been reported that swallowing is a rhythmic movement, in which the onset of the oro-pharyngeal stage of swallowing starts from the mylohyoid muscle, followed by movement of the oral and pharyngeal muscles, and reaching the superior esophageal sphincter muscle. This is defined as the oro-pharyngeal stage of swallowing. It has also been reported that along with this movement, the larynx elevates in an antero-superior direction. To investigate the swallowing movement, it would be useful to be able to detect the start of swallowing movements from the body surface. Such a device was designed in this study to investigate the relationships between the onset of laryngeal movement and the EMG initiation of the anterior digastric muscle. Although experimental conditions must be further examined, we were able to record the reproducible movement and the position of larynx using our device provides another tool for studying the swallowing movement.