Pleomorphic adenoma（PA）is the most common benign tumor in salivary glands. There are many reports of clinical and histopathological studies of PA, although the majority of these are studies of PA of the parotid gland. Although PA is a benign tumor, there is a risk of recurrence or malignant transformation, which can make clinical treatment difficult. Clarifying the differences in tumor characteristics depending on the site of occurrence may aid clinical management. In this study, to understand the detail histopathological characteristics of this tumor having various histological features, the previous cases of minor salivary gland, parotid gland, and submandibular gland were subclassified according to Seifert’s classification, and then occurrent attitude of the parenchyma and stromal component were analyzed. This retrospective study included 104 cases that had been diagnosed with PA and treated from 1985 to 2019. The cases were clinically and histopathologically analyzed by two oral pathologists for a definite diagnosis. The PAs were classified according to the classification described by Seifert et al. Our analysis showed 31.7% of the cases were subtype 1, 17.3% were subtype 2a, 1% were subtype 2b, 11.5% were subtype 2c, 25% were subtype 2e, 10.6% were subtype 3, and 2.9% were subtype 4. No cases of subtype 2d were found. Significant differences in the frequencies of occurrence of subtypes were found between the major and minor salivary glands. Differences were observed in the stromal components and their composition（subtypes）between the major and minor salivary glands. The histological differences between PAs from minor and major salivary glands may be partially explained by the anatomical differences between these two sites.

This study aimed to measure the physical properties of 13 marketed foods and gummy jelly（as a control）to comprehend their physical properties and reproducibility, with the goal of using marketed foods in a new testing method to assess consecutive masticatory and swallowing ability. Gummy jelly（UHA Mikakuto, Japan, Nara）and 13 frequently consumed marketed foods were used to assess the food texture and reproducibility of maximum compressive force. The compressing load and speed were set to 500N at 9.88 mm/s to simulate adults’ occlusal force and jaw closing speed during chewing. The pushrod jig pressed the test food 1 mm above the compression plate, and the maximum compressive force was recorded. The means of maximum compressive force were compared between the test foods using a one-way analysis of variance followed by Bonferroni-adjusted multiple comparisons. Hierarchical clustering analysis was conducted with 14 foods using maximum compressive force to interpret relationships between the foods. The reproducibility of foods was assessed by the coefficient of variation（CV）. The results suggested that traditional test foods used for assessing masticatory ability, such as gummy jelly and peanuts, exhibited significantly higher maximum compressive force than commonly marketed foods. Hierarchical clustering analysis further indicated dissimilar physical properties between traditional test foods and marketed foods. The foods’ reproducibility revealed that gummy jelly exhibited better reproducibility than peanuts. Almonds, kamaboko, and chocolate were identified to have acceptable reproducibility for the new testing method.

This study investigates the reliability and inter-day reproducibility of consecutive sounds from chewing to swallowing under standardized conditions, aiming to establish convergent validity with occluding force and the glucose elution method. Seven males and four females, aged 28.3±2.4 years, participated. Baseline measurements included occlusal force and masticatory performance. In a soundproof room, participants chewed almonds at a set rhythm, with sounds recorded continuously from chewing onset to swallowing. Recordings were processed using time series analysis software, extracting the first 10 seconds for frequency analysis and dB sum of squares calculation. The process was replicated three times, and the average was used. Inter-day reliability was assessed by replicating the entire procedure on day-1 and day-2. Intraday reliability for the dB sum of squares was evaluated using the intraclass correlation coefficient（ICC: 1, 3）separately for each day, with a paired t-test. Simple regression analysis explored associations between dB sum of squares, occlusal force, and glucose elution. Results demonstrated excellent agreement and high reliability across data sets within and between days（day-1: 0.97, day-2: 0.91）. A significant negative linear association was observed between the dB sum of squares and occlusal force two, thus, convergent validity was confirmed with occlusal force but not with masticatory performance. These findings suggest potential targets for therapeutic interventions in patients with impaired masticatory function. Future studies will extend examinations across age groups and oral health levels, following the established protocol.

The detailed three-dimensional（3D）surface structures in the maxillary first premolar （P¹）and second premolar（P²）obtained by calculating the distances between landmarks were analyzed to clarify the differences among maxillary premolars, especially structures related to distinguishing between the right and left sides. The study population included 27 boys at the elementary and junior high schools from Chiba Prefecture, Japan. Plaster casts were collected, and the 3D coordinates were recorded. Linear measurements between 9 landmarks were calculated using the 3D coordinates. The absolute and relative sizes of the outer and inner slopes of the buccal cusp were larger in P¹ than in P². The absolute sizes of the lingual cusp were similar between P¹ and P², but the relative size of the lingual cusp in P² was larger. In P¹, the curvature features were often opposite, with the buccal most prominent point located mesially. Most of P² exhibited no curvature features, and the most buccal prominent point was situated centrally. The buccal cusp tip was located more distally in P¹ than in P². Since the cusp tips in the crown structures are formed the earliest ontogenetically, P¹ may be adopt a pattern in which the mesiodistal positional relationship of the cusp differs from those of other teeth in the early developmental stages. The developmental process may produce P¹ with unique characteristics in the fully developed crown not found in other teeth.

Orthodontic root resorption（ORR）is an incident in orthodontic treatment. Previous, we reported that heavy orthodontic forces applied to cementoblast increased the development of apoptosis and root resorption. Wnt signaling is important for homeostasis and promotes differentiation of mesenchymal stem cells in the periodontal ligament into bone and cementum. Moreover, Wnt7a has involved in the apoptosis of chondrocytes, which are cementum-like cells. However, the relationship between the ORR, Wnt7a, and apoptosis of cementoblast is unknown. We examined the expression of Wnt7a, Caspase-3, and Dickkopf1（Dkk1）. Rats were divided 3 groups: Control, Optimal force（OF）, Heavy force（HF）. Then, the effects of the CF and Dkk1 on production were investigated using human cementoblast-like cells（HCEM）by real-time polymerase chain reaction（Real-time PCR）. Wnt7a-positive cells was significantly the most increased in the OF on days 5 and 7, and the Caspase-3-positive cells was significantly increased in the OF and HF. Dkk1-positive cells was significantly increased in OF and HF on day 3, and significantly increased in HF group on days 5 and 7. Compared to HF without Dkk1, Caspase-3 gene expression was significantly increased in HF with Dkk1 at 6 h and RANKL gene expression was significantly increased at 9 and 12 h. Wnt7a was highly expressed at OF, whereas Wnt7a decreased and Caspase-3 and Dkk1 increased at HF, suggesting that Caspase-3 were increased by Dkk1. Wnt7a is inhibited by Dkk1 and Caspase-3 is increased, resulting in apoptosis of cementoblast and increased ORR.

Maxillary lateral expansion is often the treatment of choice for narrowing of the dental arch width during the mixed dentition period. Although morphological changes in the maxilla and oral function before and after maxillary expansion treatment have been reported, few studies have focused on natural adaptation of the mandibular dental arch. Therefore, we investigated the relationship between the adaptation of the mandibular dentition and oral function in maxillary expansion treatment. Nineteen patients（9 boys and 10 girls; mean age, 8.9±1.1 y）diagnosed with narrow maxillary and mandibular dental arches were enrolled. Evaluations were performed at the initial examination（T1）and 3 and 6 months after the start of expansion（T2 and T3, respectively）. Oral morphology and function were compared before and after treatment. The masticatory patterns were divided into gliding and chopping types, and the amount of change in morphology and function before and after treatment was compared. Significant lateral expansion was observed in the mandibular dentition without the appliance. The maxillary first molar width increased significantly with expansion treatment. The mandibular first molar width increased for adapting to the maxillary dental arch expansion. Additionally, a positive correlation was observed between the width of the masticatory pathway at T1 and the amount of change in the width of the mandibular molars before and after treatment.　Thus, natural adaptation of the mandibular dentition after slow expansion treatment of the maxilla could have been influenced by the masticatory motion.