Impression taking for treatment is indispensable in dental practice. Many types of impression materials have been researched and developed in the past, with the advantages of convenience, high precision, and accurate impression. In recent years, digital imaging devices have become smaller, and their image quality has improved with the development of digital technology. This technology has been applied for development of an intraoral scanner (IOS), which captures the state of the intraoral region in three dimensions. Therefore, optical impressions using IOSs have been attracting attention. The use of IOS is expected to reduce the risk of various errors and infections compared to the use of conventional techniques using alginate and silicone. Furthermore, not using impression materials has many advantages, such as eliminating the risk of aspiration, cost reduction by not using materials such as gypsum, convenience of data exchange due to the use of digital data, and ease of use with dental computer-aided design/computer-aided manufacturing systems. In contrast, the precision and accuracy of IOS are comparable to those of silicone impression material in the posterior segment, but they are inferior in the cross arch. Training for effective use and capital investment is required to use IOSs. Further research on IOSs is warranted as it is a developing technology.

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Purpose: Palatal augmentation prosthesis (PAP) is used on patients with dysphagia and dysarthria. While several studies have evaluated the effects of PAP, evidence regarding the adaptation criteria, effects, and limitations of PAP are not well organized. This review aims to summarize its functions, limitations, and applications.
Procedure: To investigate the adaptation criteria, effects, and limitations of PAP, we searched the English language literature published in PubMed from its inception through April 20, 2022. The leading search terms included "palatal augmentation prosthesis."
Main findings: The primary search used keywords that reflected 31 studies. Finally, nine crosssectional studies and nine case reports were selected for full-text assessment after applying the inclusion criteria. Eleven studies described the efficacy of speech function: two for motility factors and nine for organic factors (with overlap). Thirteen studies described the effectiveness of swallowing function, four related to motility factors, and ten for organic factors (with overlap). Several studies have demonstrated that PAP effectively restores articulation and swallowing in patients with impaired tongue function after glossectomy for oropharyngeal cancer, sequelae of cranial nerve disease, or neuromuscular disease. However, few papers describe the scope of glossectomy and tongue movement restrictions, so it is impossible to describe the adaptation criteria, effects, and limitations. In this review, most case reports and cross-sectional studies did not provide information on the fabrication methods of PAP or the dentists' experience. Thus, the effect of bias on palatal morphology in PAP patients remains unclear.
Conclusions: The number of patients with dysarthria and dysphagia is increasing worldwide, similar to what is already occurring in Japan. Therefore, additional high-quality studies on the effects of PAP are required.

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Tongue coating consists of desquamated epithelium of the tongue, saliva, blood components such as leukocytes, and various oral bacteria; it is strongly related to the occurrence of oral malodor. Additionally, the tongue coating contains several oral bacteria (such as Streptococcus, Fusobacterium, Porphyromonas, and Prevotella) that not only cause oral malodor but are also associated with the risk of aspiration pneumonia in older adults. In this paper, I have explained the significance and method of tongue cleaning in oral hygiene maintenance.

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Intravenous administration of conditioned medium from stem cells of human exfoliated deciduous teeth (SHED-CM) effectively restores mechanically injured osteochondral tissues in mouse temporomandibular joint osteoarthritis. However, the underlying therapeutic mechanisms remain elusive. Here, we investigated the direct therapeutic effects of SHED-CM on inflamed primary condylar chondrocytes in vitro. Immunofluorescence staining revealed that interleukin-1β-stimulated chondrocytes showed increased expression of the catabolic marker inducible nitric oxide synthase (iNOS) and reduced expression of the anabolic marker aggrecan (ACAN). We found that SHEDCM treatment, but not conditioned medium from bone marrow mesenchymal stem cells (BMSCCM), effectively suppressed iNOS expression and elevated ACAN levels, indicating that SHEDCM converted the catabolic phenotype of inflamed chondrocytes to an anabolic phenotype. Liquid chromatography with tandem mass spectrometry analysis of SHED-CM and BMSC-CM identified eight proteins enriched in SHED-CM that are related to anti-inflammatory and/or chondrogenic processes. Of these proteins, the Wnt signal inhibitor secreted frizzled-related protein 1 (SFRP1) was the most abundantly enriched in SHED-CM. We found that treatment with the selective SFRP1 inhibitor WAY-316606 abolished the anti-catabolic and pro-anabolic effects of SHED-CM. Collectively, our study suggests that SHED-CM directly suppresses catabolism and promotes anabolic responses of inflamed primary condylar chondrocytes, which partially rely on SFRP1 function in SHED-CM. The direct action of SHED-CM may be useful to treat inflammatory cartilage diseases.

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Objectives: This study examined the characteristics of healthy teeth by analyzing the pulse transit time (PTT) and factors influencing the PTT of teeth to diagnose dental pulp using transmitted-light plethysmography (TLP).
Design: The PTT was measured in 58 healthy maxillary central incisors in 34 healthy subjects. The PTT values in earlobes (ears), fingertips, and toes were also measured for comparison purposes. In addition, the optical density of the teeth was measured. Data were analyzed using a one-way analysis of variance followed by Dunnettʼs test. Pearsonʼs correlation was performed to determine the relationship between the tooth PTT and mean blood pressure, systolic blood pressure, diastolic blood pressure, and heart rate.
Results: The average PTT of toes was significantly longer than the other three measurement sites, including the teeth. Additionally, the toes had a significantly longer average PTT among subjects in their 20s than in other age groups. There were no significant differences in the average PTT by age at the measurement sites of the teeth, ears, and fingertips, but the average PTT for the teeth and ears tended to decrease with age. The PTT of the teeth negatively correlated with the heart rate and tended to decrease with an increasing heart rate. Furthermore, the PTT of the teeth in females was significantly longer than in males.
Discussion: The average PTT of the toes was significantly longer than that at other measurement sites, possibly due to the distance from the measurement site to the heart. The average PTT of teeth tended to decrease with age, but there were no significant differences by age. The decrease in the pre-ejection period (PEP) with an increasing heart rate might have been due to the decrease in the PTT with an increasing heart rate. The loss of vascular elasticity caused by progressive atherosclerosis increases the pulse wave velocity (PWV) and decreases the PTT of teeth. Finally, the gender difference in the average PTT of teeth might have been due to the blood pressure and presence of female hormones.
Conclusion: We found that the PTT of teeth was influenced by the heart rate and elasticity of the systemic blood vessels. The PTT is useful for evaluating the blood flow in teeth and is promising for future applications in the diagnosis of dental pulp, such as in cases of chronic caries and trauma to teeth.

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Objectives: Maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) is considered the useful treatment; however, its wide effectiveness is unclear. Thus, this study aimed to explore factors affecting the efficacy of MMA for OSA using a 3-D morphological and computed fluid dynamics (CFD) analysis of the upper airway (UA).
Design: Retrospective study
Settings and participants: Twenty consecutive patients (six women, mean age 34.2 ± 12.4 years) who underwent MMA because of persistent OSA at our center.
Main outcome measures: Cone-beam computed tomography images were captured before and after MMA. We assessed the maxilla and mandibular positions, cross-sectional areas of the nasal airway (NA) and pharyngeal airway (PA), and PA space (PAS). The negative pressure of the PA, NA, and UA were measured at inspiration using CFD. We performed paired t-tests and Wilcoxon signed-rank test to compare values before and after MMA. The relationship between the airway size and pressure was evaluated using Spearman correlation coefficients and a non-linear regression analysis.
Results: PAS significantly expanded from 6.5 ± 3.4 mm to 12.2 ± 3.8 mm. NA obstruction significantly improved from -312.6 ± 265.0 Pa to -76.2 ± 129.0 Pa. Moreover, the patients were divided into four types according to the PAS size and presence of NA obstruction, namely narrow PAS with NA obstruction, narrow PAS, NA obstruction, and wide PAS and without NA obstruction.
Conclusions: We identified variations in the OSA types. However, MMA substantially improved NA obstruction and PA expansion. Thus, we considered that MMA for OSA was effective for various types.

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The reproducibility of 3D facial bone measurements was examined using CBCT images of a dry human skull model. In addition, CBCT images of 38 adult female patients diagnosed with jaw deformity and temporomandibular joint disorder were used to perform 3D facial bone measurements and were compared with the results of cephalometric analysis of the same subject group. Then, changes in craniofacial, facial cranial, and lower facial volumes due to orthognathic surgical treatment were examined in patients with Class II and Class III jaw deformities. Patient consent was obtained for this study.
1. Measurement points were set four times a day on CBCT images of human dry skulls, and another four times by the same orthodontist on different days. Using a method based on spatial vectors, the volumes of 5 tetrahedrons in the neurocranium, of 6 tetrahedrons in the facial cranium, and 8 tetrahedrons in the lower face were calculated. The reproducibility of the measurements was examined by two-way analysis of variance and intraclass correlation coefficient, which confirmed the reproducibility of the 3D measurements of the facial bones.
2. Subjects were classified into Class I group, Class II group and Class III group by the value of angle ANB of lateral roentgen cephalometric measurements. There was no significant difference in the volume of the neurocranium among three groups. The volume of the facial cranium in Class III group was tended to be smaller than Class I and Class II groups. The volume of the lower face in Class III group was significantly (p < 0.05) larger than Class II. Whereas the volume of the lower face in Class II group tended to have smaller than Class I.
3. The changes of the volume of the neurocranium, facial cranium and lower face by the orthognathic surgical treatment was examined in two cases with Class II and Class III skeletal deformity. They have coincided with the findings of facial photos, plaster models and lateral roentgen cephalograms. For the correction of the cant of occlusal plane by upward displacement of the posterior teeth could be indicated with the difference in the volume of right and left tetrahedrons.
 Since we can evaluate the volume of maxillofacial structures using the spatial vector coordinates of measurement points set on the 3D CBCT image, which allows us to evaluate more detailed 3D information by setting measurement points according to the purpose and significance.

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A girl, aged 7 years 1 month, had an anterior crossbite, crowding, and a skeletal Class I jaw-base relationship. At phase 1 treatment, anterior crossbite and crowding were improved by using a quad-helix for the maxillary arch and an expansion plate for the mandibular arch. At age of 13 years and 1 month, she had a diagnosis of anterior crowding with excessive posterior discrepancy and labially-inclined maxillary incisors. Following extraction of bilateral maxillary and mandibular second premolars, multibracket treatment was initiated. The treatment period with multibracket appliances was 2 years and 10 months. The resultant occlusion was stable throughout a 5-year retention period. Our results suggest the importance of evaluation of available space for not only anterior but also posterior teeth alignment for long-term posttreatment stability.

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