Msx1 Heterozygosity in Mice Enhances Susceptibility to Phenytoin-Induced Hypoxic Stress Causing Cleft Palate.

OBJECTIVE: Cleft palate is among the most frequent congenital defects in humans. While gene-environment multifactorial threshold models have been proposed to explain this cleft palate formation, only a few experimental models have verified this theory. This study aimed to clarify whether gene-environment interaction can cause cleft palate through a combination of specific genetic and environmental factors. METHODS: Msx1 heterozygosity in mice (Msx1+/-) was selected as a genetic factor since human MSX1 gene mutations may cause nonsyndromic cleft palate. As an environmental factor, hypoxic stress was induced in pregnant mice by administration of the antiepileptic drug phenytoin, a known arrhythmia inducer, during palatal development from embryonic day (E) 11 to E14. Embryos were dissected at E13 for histological analysis or at E17 for recording of the palatal state. RESULTS: Phenytoin administration downregulated cell proliferation in palatal processes in both wild-type and Msx1+/- embryos. Bone morphogenetic protein 4 (Bmp4) expression was slightly downregulated in the anterior palatal process of Msx1+/- embryos. Although Msx1+/- embryos do not show cleft palate under normal conditions, phenytoin administration induced a significantly higher incidence of cleft palate in Msx1+/- embryos compared to wild-type littermates. CONCLUSION: Our data suggest that cleft palate may occur because of the additive effects of Bmp4 downregulation as a result of Msx1 heterozygosity and decreased cell proliferation upon hypoxic stress. Human carriers of MSX1 mutations may have to take more precautions during pregnancy to avoid exposure to environmental risks.

Antimicrobial effects of carbamide peroxide against a polymicrobial biofilm model.

PURPOSE: To investigate the in vitro antimicrobial effects of carbamide peroxide (CP) and CP-based home bleaching agents against polymicrobial (PM) biofilms. METHODS: Using a high-throughput active attachment model, PM biofilms were cultured on glass coverslips by diluting the stimulated saliva of one healthy adult. All experiments were performed anaerobically in McBain medium, which was refreshed twice daily. After biofilm formation for 24 or 72 hours, the biofilms were treated with 0.5%, 2.5%, 5%, or 10% CP, 20-fold dilutions of HiLite Shade Up (HS) or Opalescence Regular (OR), 0.2% chlorhexidine digluconate (CHX), 0.2% NaF, or deionized water (n = 10 each). Biofilms were dispersed and the number of colony forming units (CFU) was measured on tryptic soy agar blood plates. Coverslips containing 72-hour biofilms treated with 0.5% and 10% CP and deionized water were stained and scanned by confocal laser scanning microscopy (CLSM). RESULTS: Treatment of 24- and 72-hour biofilms with HS, OR and CH yielded significantly fewer colonies than treatment with water or 0.2% NaF. No growing colonies were observed after treatment with 10% CP. CLSM showed that the percentage of dead bacteria increased as the concentration of CP increased.

Imaging characteristics of gubernaculum tracts in patients with cleidocranial dysplasia: a computed tomography study.

OBJECTIVES: To elucidate the imaging characteristics of the gubernaculum tract (GT) in patients with cleidocranial dysplasia (CCD) as visualized with computed tomography (CT). STUDY DESIGN: This was a retrospective analysis of the presence and shape of GTs of unerupted permanent teeth and supernumerary teeth on CT in 9 patients with CCD. RESULTS: The overall GT detection rate for unerupted permanent teeth was 83.5% (81/97), with no significant difference between permanent teeth without and with adjacent supernumerary teeth (P = .414). The overall GT detection rate for unerupted supernumerary teeth was 83.1% (49/59). Of the 156 total unerupted teeth analyzed, 83.3% (130/156) were judged to have GTs. No significant difference in detection rate of GTs was found between permanent and supernumerary teeth (P > 0.999). A composite morphology consisted of a single GT for a permanent unerupted tooth with 1 or 2 supernumerary teeth in which the dental follicles of the permanent and supernumerary teeth were confluent. In total, 44 groups consisted of 1 permanent and 1 or 2 supernumerary teeth; 79.5% (35/44) had GTs. CONCLUSIONS: A specific composite structure of GTs and dental follicles may signify that 2 or 3 teeth are derived from a single dental lamina in patients with CCD. In such cases, tooth eruption may fail due to the presence of only 1 GT for multiple teeth.

Comparison of the distribution of the Bartholin and/or Rivinus salivary ducts assessed with magnetic resonance-sialography in patients with ranula and in healthy subjects.

Background: The distribution and drainage of the sublingual gland ducts have various patterns that might be related to sublingual gland-related diseases, including ranula. This study aimed to elucidate the characteristics of the distribution of Bartholin and/or Rivinus ducts in patients with ranula using magnetic resonance (MR) sialography. Methods: In this retrospective cross-sectional study, the distributions and drainage patterns of sublingual gland ducts on MR sialography were classified in 74 subjects without sublingual gland-related disease as confirmed by both medical history and clinical examination and 15 patients with ranula, respectively. All patients had visited Kyushu Dental University Hospital from July 2015 to June 2022 to undergo MR imaging. Data on the distributions and drainage patterns of the sublingual gland ducts, including the characteristics of the Bartholin and/or Rivinus ducts, were then statistically compared between subjects without sublingual gland-related disease and patients with ranula. The images were assessed by an experienced oral and maxillofacial radiology specialist certified by the Japanese Society for Oral and Maxillofacial Radiology. The distributions (five groups) and drainage patterns (three patterns) of the sublingual gland ducts on MR sialography were classified in reference to previous studies, with some modifications in all subjects without sublingual gland-related disease and patients with ranula. Results: A significant difference in the distribution of the ducts (P<0.001), with a low number of patients exposing an undetected canal or Rivinius duct, was found in the group of patients with ranula (P<0.05). Regarding drainage patterns, no patient with ranula presented a Rivinius duct only. A significant difference in the drainage patterns of the sublingual gland ducts on MR sialography was observed between subjects without sublingual gland-related disease and patients with ranula (P=0.001). Conclusions: The present results suggest that the distribution of the sublingual gland ducts, mainly, the Bartholin duct, may be related to ranula formation. These findings also demonstrate that MR sialography contributes well to preoperative evaluation and is effective for assessing the complex excretory distribution of the sublingual gland ducts.

Imaging Characteristics of Embedded Tooth-Associated Cemento-Osseous Dysplasia by Retrospective Study.

BACKGROUND: Since there are many differential diagnoses for cemento-osseous dysplasia (COD), it is very difficult for dentists to avoid misdiagnosis. In particular, if COD is related to an embedded tooth, differential diagnosis is difficult. However, there have been no reports on the characteristics of the imaging findings of COD associated with embedded teeth. The aim of the present study was to investigate the occurrence and imaging characteristics of cemento-osseous dysplasia (COD) associated with embedded teeth, in order to appropriately diagnose COD with embedded teeth. METHODS: The radiographs with or without histological findings of 225 patients with COD were retrospectively analyzed. A retrospective search through the picture archiving and communication system (PACS) of the Division of Oral and Maxillofacial Radiology of Kyushu Dental University Hospital was performed to identify patients with COD between 2011 and 2022. RESULTS: Fifteen COD-associated embedded mandibular third molars were identified in 13 patients. All 13 patients were asymptomatic. On imaging, COD associated with embedded mandibular third molars appeared as masses that included calcifications around the apex of the tooth. On panoramic tomography, COD showed inconspicuous internal calcification similar to that of odontogenic cysts or simple bone cysts, especially in patients with COD only around the mandibular third molar region. Those with prominent calcification resembled cemento-ossifying fibroma, calcifying epithelial odontogenic tumor, calcifying odontogenic cyst, adenomatoid odontogenic tumor, and so on, as categories of masses that include calcifications on panoramic tomography and computed tomography. CONCLUSIONS: The current investigation is the first to report and analyze the imaging characteristics of COD associated with embedded teeth. It is important to consider the differences between COD and other cystic lesions on panoramic tomography, and the differences between COD and masses that include calcifications on CT.

Effect of COVID-19 on dental telemedicine in Japan.

BACKGROUND/PURPOSE: In Japan, medical and dental care is provided by the universal health insurance system. The Ministry of Health, Labour, and Welfare (MHLW) in Japan sets the rules for health care services provided by health insurance. The MHLW issued a notice in 2020 permitting telemedicine and dental telemedicine for the first visit and for follow-up visits to prevent the spread of COVID-19 infection. We conducted this study to clarify the status of dental telemedicine during 2020. MATERIALS AND METHODS: We used data from lists obtained on the MHLW website in the analysis. We investigated the number of dental institutions conducing dental telemedicine for the first visit and for follow-up visits by prefecture. RESULTS: In each prefecture, fewer dental institutions conducted telemedicine for the first visit than for follow-up visits. Regions with large metropolitan areas had higher numbers of dental institutions conducting dental telemedicine for the first visit and follow-up visits. Private dental clinics provided the largest proportion of dental telemedicine for the first visit, and general hospitals provided the largest proportion for follow-up visits. CONCLUSION: Our study findings indicated that many dental institutions in Japan made efforts to provide dental services via dental telemedicine using the telephone or online with video to help prevent the spread of COVID-19 infection. Dental telemedicine can help patients to access dental services and dental care, thereby expanding the potential of dental telemedicine in Japan.

New vertebral compression fractures after prophylactic vertebroplasty in osteoporotic patients.

OBJECTIVE: Previous studies have shown the possible efficacy of prophylactic cement injection for nonfractured vertebrae during percutaneous vertebroplasty for compression fractures. The purpose of this study was to investigate risk factors for subsequent fractures after prophylactic percutaneous vertebroplasty. MATERIALS AND METHODS: This retrospective study included 116 patients with osteoporotic compression fractures who underwent prophylactic percutaneous vertebroplasty. The patients were monitored with physical examinations and radiographs at 1 day and at 3 and 12 months after percutaneous vertebroplasty, and if back pain recurred. We analyzed the following multiple covariates to determine whether they were associated with recurrence: age, sex, steroid use, and the preoperative number of unhealed or chronic compression fractures. RESULTS: Subsequent fractures in any vertebra occurred within 3 months after the procedure at 26 vertebrae in 21 patients (18.1%), and 36 occurred in 28 patients (24.1%) within 12 months. The occurrence of subsequent fractures within 12 months depended on the preoperative number of unhealed vertebrae: the occurrence rate was 16.9% (11/65) for one vertebra, 27.0% (10/37) for two vertebrae, and 50.0% (7/14) for three or more vertebrae. The incidence of subsequent fractures was significantly higher in patients with three or more fractures than in those with one fracture (p < 0.05). There were no statistically significant differences for the other factors. CONCLUSION: Patients with three or more fractures tended to have subsequent fractures, despite undergoing prophylactic percutaneous vertebroplasty. However, there was no increased risk of subsequent fractures related to prophylactic percutaneous vertebroplasty.

Imaging peculiarities of gubernaculum tracts in molars as accessional teeth on CT.

OBJECTIVES: The shapes of gubernaculum tracts (GTs) in molars as accessional teeth remain unidentified. To elucidate imaging peculiarities of GTs in molars with aging on multidetector-row computed tomography (MDCT). MATERIAL AND METHODS: This retrospective study was conducted using CT images, including maxillary and mandibular molars, with no abnormal findings from 239 patients. Shapes of alveolar bone, GTs, and dental sacs of the maxillary and mandibular molars were analyzed multi-sectionally. Correlations between 2- and 3-dimensional imaging figures of GTs in molars and chronological age or stage of molar formation were analyzed. RESULTS: Some forms of GTs in maxillary and mandibular third molars were observed. In the early stage, GTs were visualized as bone defect lines on the dentition and grooves on the mesial alveolar crest continuous with the dental sac to mesial tooth bud. GTs of the third molar formed a J-shape in maxillary teeth and Y-shape in mandibular teeth in the middle stage, as alveolar bone around the GT developed. In the mature stage, the course of the GT changed to straight and perpendicular. Some GT forms were also identified in first and second molars. Significant correlations were found between GT alterations and chronological age or stage of molar formation. Moreover, tracts continuing from the distal side of mandibular third molars were detected. CONCLUSIONS: This paper describes the peculiarities and process of progression for GTs in molars, and the existence of tracts continuing from the distal side of mandibular third molars, unlikely dentition with deciduous predecessors. These preliminary data should prove beneficial for studies focusing on GTs in molars.

Overview of Radiological Studies on Visualization of Gubernaculum Tracts of Permanent Teeth.

The eruption pathway from the dental follicle to the gingiva for permanent teeth is known as the gubernaculum tract (GT), a physiologic structure thought to play a role in tooth eruption. Cone beam computed tomography and multi-detector computed tomography have recently been used to visualize the GT, with the results indicating that this structure might be related to the normal eruption of teeth. By contrast, curved and/or constricted GTs may lead to abnormal tooth eruption. In addition, complex odontomas have been reported from within the GT or dental sac of unerupted permanent teeth. If an odontoma occurs within the GT, the tooth will not erupt normally. Moreover, the imaging characteristics of the GT from the top of the odontogenic mass to the alveolar crest are extremely useful for making a differential pathological diagnosis and for differentiating between odontogenic and non-odontogenic masses. Therefore, radiological studies on the GT have been attracting increasing attention. Given this background, the present review aims to clarify the imaging characteristics and review recent studies on the GT considering the importance of the research.

Effects of stellate ganglion block on postoperative trigeminal neuropathy after dental surgery: a propensity score matching analysis.

This study aimed to evaluate the effects of stellate ganglion block (SGB) on postoperative trigeminal neuropathy (TNP) after dental surgery. This was a retrospective study based on the medical records of all patients with postoperative TNP at Kyushu Dental University Hospital from 2014 to 2019. Patients were divided into the SGB group (received SGB) and non-SGB group (did not receive SGB). We evaluated the severity of TNP at 3 months after surgery and the incidence rate of abnormal sensations. Abnormal sensations were counted using patients' reports of uncomfortable symptoms during the treatment, including dysaesthesia, allodynia, and hyperalgesia. A propensity score (PS) matching analysis was performed to evaluate these data. After PS matching, amongst others, the force equivalent values of the Semmes-Weinstein test at 3-months post-treatment were significantly lower in the SGB group than in the non-SGB group (2.00 ± 0.44 vs 2.30 ± 0.48; p < 0.05). In addition, after PS matching, the incidence rate of abnormal sensations during the treatment was significantly lower in the SGB group than in the non-SGB group (10 cases [4.7%] vs 22 cases [10.3%]; p < 0.05). Collectively, the findings support that SGB may improve the recovery from postoperative TNP and reduce the incidence rate of abnormal sensations after dental surgery.

Frequency of Daily Tooth Brushing and Development of any Type of Malignancy.

BACKGROUND/AIM: The aim of this study was to evaluate the association between the frequency of daily tooth brushing and the development of any type of malignancy. PATIENTS AND METHODS: We conducted a retrospective longitudinal study, including all adult participants who underwent health check-ups. Primary outcome was the development of any type of malignancy, compared to the frequency of daily tooth brushing, adjusting for potential confounders. RESULTS: A total of 71,449 participants were included and 5,025 participants developed a certain type of malignancy. Not brushing everyday (Odds Ratio (OR)=1.52, 95% Confidence Interval (CI)=1.03-2.25) and brushing once a day (OR=1.25, 95%CI=1.16-1.35) had significantly higher ORs for the outcome than brushing after every meal, although those who brushed once to twice a day had significantly lower OR (OR=0.78, 95%CI=0.72-0.83). CONCLUSION: As the frequency of daily tooth brushing increased, except for brushing after every meal, the development of all types of malignancies decreased.

Epidermal growth factor receptor-targeted sonoporation with microbubbles enhances therapeutic efficacy in a squamous cell carcinoma model.

Sonoporation is a drug and gene delivery system using ultrasonication that allows the intracellular delivery of foreign molecules that cannot enter cells under normal conditions. We previously reported that sonoporation with microbubbles (MBs) could achieve effective intracellular drug delivery to human gingival squamous carcinoma Ca9-22 cells. In this study, we developed anti-epidermal growth factor receptor (EGFR) antibody-conjugated MBs (EGFR-MBs) and evaluated their capacity to enhance anti-cancer drug toxicity in vitro and in vivo. We first assessed the effect of sonoporation with EGFR-MBs on Ca9-22 cells by the WST-8 assay, flow cytometry and Hoechst's staining in vitro. Sonoporation and EGFR-MB had a strong cytotoxic effect on Ca9-22 cells with low-dose bleomycin. Furthermore, bleomycin delivery using sonoporation with EGFR-MBs remarkably increased the number of apoptotic cells. We next examined the effect of EGFR-MBs in a murine squamous cell carcinoma model. Bleomycin delivery by sonoporation with EGFR-MBs exhibited remarkable antitumor activity. Together, our results show that EGFR-MBs and ultrasound treatment increases the efficacy and specificity of intracellular drug uptake, suggesting this could be a novel drug-targeting modality for oral squamous cell carcinoma chemotherapy treatment.

A Study of the Maxillary Sinus Volume in Elderly Persons Using Japanese Cadavers.

In this paper, using full-body CT images of elderly and advanced elderly Japanese cadavers, we measure maxillary and other paranasal sinus volumes in order to examine the effects of age, sex, presence or absence of maxillary molars, and other factors on changes to maxillary sinus volume. The research subjects consisted of 77 of 95 cadavers donated to the Kanagawa Dental University between 2012 and 2014, which average age was 82.6 ± 10 years (33 were male, average age 79.3 ± 8.3 years, and 44 were female, average age 85.1 ± 11.7 years). Sinus volume was measured from full-body CT images on the horizontal plane and computed using the 3D volume rendering software. The average maxillary sinus volume was 31.3 ± 13.2 cm3 (average value ± one standard deviation; hereafter the same), with values of 32.9 ± 13.2 cm3 (6.7 cm3 ～ 55.7 cm3) for males and 29.6 ± 12.5 cm3 (5.5 cm3 ～ 52.9 cm3) for females. In this report, we studied the effects of aging, sex, and state of remaining molars on changes to paranasal sinus volume in the maxillary sinus. These results give additional information about maxillary sinus volume of Japanese oldest-old peoples.

Reactive oxygen species production in mitochondria of human gingival fibroblast induced by blue light irradiation.

In recent years, it has become well known that the production of reactive oxygen species (ROS) induced by blue-light irradiation causes adverse effects of photo-aging, such as age-related macular degeneration of the retina. Thus, orange-tinted glasses are used to protect the retina during dental treatment involving blue-light irradiation (e.g., dental resin restorations or tooth bleaching treatments). However, there are few studies examining the effects of blue-light irradiation on oral tissue. For the first time, we report that blue-light irradiation by quartz tungsten halogen lamp (QTH) or light-emitting diode (LED) decreased cell proliferation activity of human gingival fibroblasts (HGFs) in a time-dependent manner (<5 min). Additionally, in a morphological study, the cytotoxic effect was observed in the cell organelles, especially the mitochondria. Furthermore, ROS generation induced by the blue-light irradiation was detected in mitochondria of HGFs using fluorimetry. In all analyses, the cytotoxicity was significantly higher after LED irradiation compared with cytotoxicity after QTH irradiation. These results suggest that blue light irradiation, especially by LED light sources used in dental aesthetic treatment, might have adverse effects on human gingival tissue. Hence, this necessitates the development of new dental aesthetic treatment methods and/or techniques to protect HGFs from blue light irradiation during dental therapy.

Association between periodontitis and systemic bone mineral density in Japanese community-dwelling postmenopausal women.

OBJECTIVE: The purpose of this cross-sectional study was to evaluate the association between loss of attachment (LA) which is clinical index of periodontitis and bone mineral density (BMD) of the lumbar vertebrae and femur measured with dual energy X-ray absorptiometry (DXA) in Japanese community-dwelling postmenopausal women. SUBJECTS AND METHODS: Subjects were 374 [corrected] women aged 55-74. The oral cavity was divided into 6 areas according to the WHO's method for the determination of the clinical attachment level score (CALscore); the LA was measured at 6 sites using a WHO probe in 17, 16, 11, 26, 27, 37, 36, 31, 46, and 47, and the values were recorded in mm. Then, we assessed BMD of the lumbar vertebrae (L2-L4) and femur (femoral neck, proximal part) by DXA. Based on these data, analysis of covariance was used to estimate relation between periodontitis and systemic BMD status excluding effect of age. Multiple linear regression analysis was used to estimate relation between periodontitis and BMD adjusted for 17 variables. RESULTS: Significant differences were observed in the mean value between the mean CALscore=0 and CALscore≥1 groups in the Z value in lumbar vertebrate (106.9±18.7 vs. 102.3±1.0, p<0.05, t-test). Multiple regression analysis was conducted using the mean LA as dependent variable. Lumbar vertebral BMD (regression coefficient: B=-1.039±0.379, p=0.007), femoral neck BMD (B=-1.332±0.627, p=0.034), and proximal femoral BMD (B=-1.329±0.536, p=0.014) all exhibited a significant negative correlation with the mean LA. CONCLUSION: A significant negative correlation was observed between periodontal disease and truncal bone BMD in this study.

Prophylactic vertebroplasty: cement injection into non-fractured vertebral bodies during percutaneous vertebroplasty.

RATIONALE AND OBJECTIVES: We investigated the efficacy of prophylactic cement injection into the vertebral body adjacent to fractured vertebra to prevent new fractures after percutaneous vertebroplasty (PV). MATERIALS AND METHODS: Between February 2002 to August 2004, PV was performed for osteoporotic compression fractures in 89 consecutive patients. All patients underwent PV for only fractured vertebrae. Between September 2004 and October 2006, we performed prophylactic cement injection for 155 patients, with cement injected into the non-fractured vertebra adjacent to the fractured vertebra, immediately above the fractured vertebra in the same procedure. We evaluated the frequency of new vertebral fractures and the efficacy of prophylactic therapy. RESULTS: In the non-prophylactic group, 15 of 89 patients (16.8%) developed new fractures within 3 months and 20 of 89 patients (22.4%) developed new painful compression fractures within a year after the first PV. These fractures occurred mostly in adjacent vertebra, particularly in the vertebra immediately superior to the treated one and occurred in the lower thoracic and upper lumbar spine. In the prophylactic group, 7 of 155 patients (4.5%) developed new compression fractures within 3 months and 15 of 155 patients (9.7%) developed new compression fractures within 1 year. Statistical analysis showed that fewer new fractures developed in the prophylactic group than in the non-prophylactic group at both 3 months (P = .0020, Fisher's exact test) and 1 year (P = .0079). CONCLUSIONS: Prophylactic cement injection into non-fractured vertebrae adjacent to fractured vertebrae may prevent new compression fractures after vertebroplasty for osteoporotic patients.

A quantitative approach for measuring crowding in the dental arch: Fourier descriptors.

Dental crowding is defined as a discrepancy between tooth size and jaw size that results in a misalignment of the tooth row. Proposed reasons for crowding include excessively large teeth, small jaws, and a combination of both. Nevertheless, the parameters that would allow the prediction of crowding have not been identified. This study compared the shape of crowded and uncrowded dental arches, matched for size and sex. The application of elliptical Fourier functions (EFFs) provided an accurate numeric description of the dental arch form. Dental casts from the Nihon University School of Dentistry at Matsudo, Chiba, Japan, were studied. Group I, the control group, consisted of 118 dental cast pairs (49 female, 69 male, aged 20.40 +/- 1.68 years [mean +/- SD]) with little or no crowding. Group II, which exhibited crowding, consisted of 78 dental cast pairs (64 female, 14 male, aged 19.67 +/- 4.95 years). From photographs, a set of 24 homologous points describing the tooth row was identified. These points were then fitted with EFFs. Each maxillary and mandibular outline was subsequently standardized for size by scaling the bounded area to a constant 10,000 mm(2). These "shape only" data were used to assess differences between arches in the 2 groups. By multivariate analysis of variance, statistically significant shape differences between groups I and II were obtained for both arches. Patients with crowding exhibited more variability than did the controls. This variability was illustrated with canonical axes derived from discriminant function analysis.