Oral plexiform schwannoma with unusual epithelial induction

Rare epithelial structures in benign nerve sheath tumors are almost always glandular in appearance. We describe a case of intraoral plexiform schwannoma with concurrent squamous epithelial hyperplasia. The lesion occurred as a pigmented nodule on the gingiva of a 35‐year‐old woman with no systemic involvement. Histologically, unencapsulated, plexiform fascicular proliferations of schwann cells could be traced from the submucosa to the lamina propria, finally making direct contact with heavily pigmented, elongated rete ridges of the overlying epithelium. Also noted was a schwannian network centered on clustered odontogenic epithelial rests of mature squamous‐type, the number and size of which had markedly increased. Impressive immunoprofiles of periepithelial neural microfascicles included the complete absence of axon and perineurium and the unexpected presence of endoneurial fibroblasts. The repertoire of epithelial changes was in a confined area with no extension beyond, supporting hyperplasia induction by an underlying/surrounding schwannoma.     

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.     

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.     

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.     

The Japanese version of the Oral Health Impact Profile (OHIP)--validation among young and middle-aged adults

OBJECTIVE: To validate the Japanese version of the Oral Health Impact Profile (OHIP-J) for use among young and middle-aged adults. Evaluating the criterion validity was particularly important in this study. METHOD: The original Oral Health Impact Profile (OHIP) was translated into Japanese. Data from 6,079 subjects aged 20-59 were collected by means of a self-administered questionnaire and the oral condition records of a sample of workers. The survey involved items for the OHIP-J and self-rated oral health, denture wearing, number of missing teeth, work type, occupational rank, gender, and age. We adopted a self-rated oral health and number of missing teeth as validity criteria for this analysis. RESULTS: Using multiple linear regression analysis, the adjusted total OHIP-J scores for respondents who rated their oral health as poor were higher than those who did not (46.6 vs. 27.6; p<0.001). The variable of missing teeth was significantly associated with the OHIP-J total and subscale scores independent of gender, age and denture wearing (p<0.001). CONCLUSIONS: These findings suggest that the OHIP-J is suitable for assessing the oral health-related quality of life of young and middle-aged adults in Japan.     

Cigarette smoking, alcohol drinking, and oral and pharyngeal cancer mortality in Japan

Objectives:  To prospectively examine the association of cigarette smoking and alcohol drinking with oral and pharyngeal carcinogenesis, we analyzed data from a nation-wide large-scale cohort study in Japan.
Methods:  A total of 34 136 men and 43 711 women aged 40–79 years were included in the study. The Cox proportional hazard model was used to estimate the relative risk (RR) and 95% confidence interval (95% CI) of oral and pharyngeal cancer for smoking and drinking by sex, while adjusting for age, consumption of green tea, preference for salty foods, and consumption of green yellow vegetables.
Results:  Current smokers were found to have a higher risk of death caused by oral and pharyngeal cancer compared with non-smokers in both sexes: the RR was 2.6 (95% CI: 1.0–6.7) in men and 8.2 (95% CI: 2.1–32.1) in women. Men who drank more than 46 g ethanol per day had an approximately threefold increased risk of oral and pharyngeal cancer. Simultaneous exposure to both factors was significantly associated with an elevated risk of oral and pharyngeal cancer (RR: 3.3, 95% CI: 1.1–9.6).
Conclusions:  The result supports the carcinogenic effect of cigarette smoking and alcohol drinking on the oral cavity and pharynx.