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Oral health screening is important for maintaining and improving quality of life. The present study aimed to determine whether patients with a certain level of alveolar bone resorption could be screened by salivary bacterial test along with their background information. Saliva samples were collected from 977 Japanese patients, and the counts of each red-complex, that is, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, were measured using quantitative polymerase chain reaction analysis. Mean bone crest levels (BCLs) were measured using a full-mouth periapical radiograph. Multiple logistic regression analysis was used to determine associations between BCLs (1.5–4.0 mm in 0.5 mm increments) and explanatory variables, such as the number of each red-complex bacteria and the patients' age, sex, number of teeth, stimulated saliva volume, and smoking habits. When the cutoff BCL value was set at 3.0 mm, the area under the curve, sensitivity, and specificity values were optimal at 0.86, 0.82, and 0.76, respectively. In addition, all tested explanatory variables, except sex and T. denticola count, were significantly associated with BCLs according to a likelihood ratio test (p < 0.05). Additionally, the odds ratio (OR) was substantially increased when a patient was >40 years old and the bacterial count of P. gingivalis was >107 cells/µL (OR: >6). Thus, P. gingivalis count and patients' background information were significantly associated with the presence of a certain amount of bone resorption, suggesting that it may be possible to screen bone resorption without the need for radiography or oral examination. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Orofacial clefts (OFCs) are common and etiologically complex birth defects. This study explored potential genetic differences in a pair of Japanese monozygotic (MZ) twins with different forms of OFC using whole‐genome sequencing. Subjects and Methods: One co‐twin (MZ‐1) presented with nonsyndromic bilateral cleft lip and palate; the other co‐twin (MZ‐2) had nonsyndromic bilateral cleft lip and unilateral left‐sided cleft alveolus. Neither parent had an OFC. Craniofacial morphologic features and potential genetic differences were compared using standard cephalometry and whole‐genome sequencing, respectively. Results: Morphologically, MZ‐1 had a smaller vertical mandibular height, compared to MZ‐2. However, no discordant genetic differences were detected. Moreover, both twins and their parents harbored rare candidate gene variants (GRHL3; TPM1) considered to be associated with OFCs. Conclusion: The observed differences between MZ‐1 and MZ‐2 in craniofacial morphology assessed by cephalograms might be directly attributable to the effects of the OFC on growth and/or differences in surgical history, given the lack of any differences in genetic background. However, comparisons of discordant MZ twins should continue to identify novel candidates that might control OFC or that might partly explain the missing heritability for this common birth defect, in addition to understanding craniofacial growth and development. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the association between buccal mucosa ridging and oral or occlusal statuses among older people. Subjects and Methods: This cross‐sectional study examined 262 independent older people (mean age, 74.2 ± 5.9 years) who participated in the Kyoto Elderly Physical Fitness Measurement Research Project. The predictor variables were oral statuses (number of present teeth and torus palatinus, torus mandibularis, temporomandibular joint noise, clenching, or grinding) and oral functions (occlusal pressure, cheek pressure, oral diadochokinesis, and tongue pressure). The outcome variable was the buccal mucosa ridging status (presence or absence). Additional variables were age, sex, body mass index, grip strength, and wearing dentures. We compared these variables between participants with and without buccal mucosa ridging using a univariate analysis and multiple logistic regression analysis. Results: Buccal mucosa ridging was present in 177 (67.6%) people. Multiple logistic regression analysis revealed a close association of buccal mucosa ridging with torus mandibularis, tooth clenching and grinding and occlusal pressure, and cheek pressure. Conclusions: Over 50% of the participants showed buccal mucosa ridging; this was significantly associated with higher cheek pressure, lower occlusal pressure, torus mandibularis, and tooth clenching and grinding. [ABSTRACT FROM AUTHOR]

Sphingomyelin phosphodiesterase 3 ( Smpd3), which encodes neutral sphingomyelinase 2 (nSMase2), is a key molecule for skeletal development as well as for the cytodifferentiation of odontoblasts and alveolar bone. However, the effects of nSMase2 on the cytodifferentiation of periodontal ligament (PDL) cells are still unclear. In this study, the authors analyzed the effects of Smpd3 on the cytodifferentiation of human PDL (HPDL) cells. The authors found that Smpd3 increases the mRNA expression of calcification-related genes, such as alkaline phosphatase (ALPase), type I collagen, osteopontin, Osterix (Osx), and runt-related transcription factor (Runx)-2 in HPDL cells. In contrast, GW4869, an inhibitor of nSMase2, clearly decreased the mRNA expression of ALPase, type I collagen, and osteocalcin in HPDL cells, suggesting that Smpd3 enhances HPDL cytodifferentiation. Next, the authors used exome sequencing to evaluate the genetic variants of Smpd3 in a Japanese population with aggressive periodontitis (AgP). Among 44 unrelated subjects, the authors identified a single nucleotide polymorphism (SNP), rs145616324, in Smpd3 as a putative genetic variant for AgP among Japanese people. Moreover, Smpd3 harboring this SNP did not increase the sphingomyelinase activity or mRNA expression of ALPase, type I collagen, osteopontin, Osx, or Runx2, suggesting that this SNP inhibits Smpd3 such that it has no effect on the cytodifferentiation of HPDL cells. These data suggest that Smpd3 plays a crucial role in maintaining the homeostasis of PDL tissue. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to examine experimental tooth movement into regenerated bone in alveolar cleft with mesenchymal stem cells and a granulated carbonated hydroxyapatite scaffold. Design: An artificial bone defect was created bilaterally in upper incisor regions of beagle dogs to simulate alveolar clefts in patients with cleft palate. The mesenchymal stem cells derived from the iliac bone marrow were cultured and transplanted with carbonated hydroxyapatite into the bone defect area. Carbonated hydroxyapatite alone was transplanted on the control side. Six months after the transplantation, multi-bracket appliances were attached to the lateral incisors and canines on both sides of the maxilla to exert an orthodontic force of 100 x g using an elastic chain. The distance between lateral incisor and canine was measured, and standardized x-ray images were taken every month. The tissue after tooth movement was evaluated by histological observation. Results: The experimental tooth movement, accompanied by resorption of regenerated bone and new bone formation, was achieved on the experimental and control sides. Although there was no difference in the amount of tooth movement obtained on the experimental and control sides during the 6-month experimental period, the rate of tooth movement varied on the control side; whereas, the rate was consistent on the experimental side. Root resorption of the tooth was observed on the control side in one dog. Conclusion: It is suggested that mesenchymal/carbonated hydroxyapatite transplantation therapy has great potential as a new treatment modality for bone regeneration in patients with cleft palate. [ABSTRACT FROM AUTHOR]

Background and Objective Factors such as vascularization of the periodontium, inflammatory reactions and immune response affect the oral environment and ecology, decreasing host resistance and promoting the development of symptoms and the advancement of periodontal disease. Fatigue also influences the hypothalamic-pituitary-adrenal axis and reports relate it to systemic resistance. The aim of this study was to evaluate whether fatigue is a modifying factor for periodontal disease in rats. Material and Methods We divided 24 3-wk-old male Sprague-Dawley rats randomly into the following four groups: control; fatigue (deep sleep deprivation for 7 d); infection (rats inoculated with carboxymethyl cellulose containing periodontopathic bacteria); and compound (combined fatigue and infection conditions). Weight, serum corticosterone levels, serum albumin levels, interleukin-1β and tumor necrosis factor-α expression levels and distance from the cement-enamel junction to the alveolar bone crest were measured at baseline, and on the 36th (before sleep deprivation), 43rd (immediately after sleep deprivation) and 57th d (end of experiment). Results Immediately after sleep deprivation and at the end of the experiment, weight gain in the fatigue and compound groups was significantly lower than in controls ( p < 0.05). Immediately after sleep deprivation, serum corticosterone levels were significantly higher in the fatigue and compound groups than in controls ( p < 0.05). Moreover, serum albumin levels were significantly lower in the fatigue and compound groups than in controls ( p < 0.05). Immediately after sleep deprivation, gene expression of interleukin-1β was significantly higher in the infection and compound groups than in controls ( p < 0.05). Moreover, gene expression of tumor necrosis factor-α was significantly higher in the compound group than in controls ( p < 0.05). At the end of the experiment, the distance from the cement-enamel junction to the alveolar bone crest was significantly higher in the infection and compound groups than in controls ( p < 0.05). Moreover, the distance was significantly higher in the compound group than in the infection group. Conclusions Fatigue worsened systemic health in rats and increased gingival inflammation and alveolar bone loss in experimental periodontitis. In conclusion, our results suggest that fatigue is a modifying factor for periodontal disease in rats. [ABSTRACT FROM AUTHOR]

Background The domesticated legume, Canavalia gladiata (commonly called the sword bean), is known to contain canavanine. The fruit is used in Chinese and Japanese herbal medicine for treating the discharge of pus, but its pharmacological mechanisms are still unclear. Objectives This study examined the effect of sword bean extract ( SBE) on (i) oral bacteria and human oral epithelial cells in vitro, and (ii) the initiation and progression of experimental Porphyromonas gingivalis-induced alveolar bone resorption in rats. Material and Methods A high-performance liquid chromatography/ ultraviolet method was applied to quantitate canavanine in SBE. By assessing oral bacterial growth, we estimated the minimum inhibitory concentration and minimum bactericidal concentration of SBE, canavanine, chlorhexidine gluconate ( CHX) solution. The cytotoxicity of SBE, canavanine, CHX, leupeptin and cystatin for KB cells was determined using a trypan blue assay. The effects of SBE, canavanine, leupeptin and cystatin on Arg-gingipain (Rgp) and Lys-gingipain (Kgp) were evaluated by colorimetric assay using synthetic substrates. To examine its effects on P. gingivalis-associated periodontal tissue breakdown, SBE was orally administered to P. gingivalis-infected rats. Result Sword bean extract contained 6.4% canavanine. SBE and canavanine inhibited the growth of P. gingivalis and Fusobacterium nucleatum. The cytotoxicity of SBE, canavanine and cystatin on KB cells was significantly lower than that of CHX. Inhibition of Rgp with SBE was comparable to that with leupeptin, a known Rgp inhibitor, and inhibition of Kgp with SBE was significantly higher than that with leupeptin at 500 μg/ mL ( p < 0.05). P. gingivalis-induced alveolar bone resorption was significantly suppressed by administration of SBE, with bone levels remaining comparable to non-infected animals ( p < 0.05). Conclusion The present study suggests that SBE might be effective against P. gingivalis-associated alveolar bone resorption. [ABSTRACT FROM AUTHOR]

Objective: Synthetic octacalcium phosphate and porcine atelocollagen composites significantly enhanced bone regeneration more than p-tricalcium phosphate collagen composite and hydroxyapatite collagen composite in a rat cranial defect model. However, the long-term stability and quality of octacalcium phosphate collagen (OCP/Col) composites-derived regenerated bone, when implanted in a canine alveolar cleft model, have yet to be elucidated. The present study investigated the longterm stability and quality of bone regenerated by OCP/Col. Design: Disks of OCP/Col or collagen were implanted in a canine alveolar-cleft model (n = 6). Then, bone regeneration in the implanted areas was investigated macroscopically, radiograph-ically, and histologically at 10 months after implantation. In addition, three-dimensional quantitative images of regenerated bone were analyzed by microcomputed tomography. Results: Macroscopically, the OCP/Col treated alveolus was clearly augmented, and radio-opacity in the OCP/Col implanted area was comparable to that of the original alveolus bone. On histological analysis, the area was mostly filled with newly formed bone, and a few granules of implanted OCP/Col were enclosed in it. In the microcomputed tomography analysis, the regenerated bone volume in the OCP/Col group was larger than that in the collagen group. OCP/ Col-derived bone consisted of outer cortical and inner cancellous structure with dense trabeculae and seemed like the original bone structure. Conclusions: OCP/Co composites could be a useful bone regenerative material to substitute for autogenous bone because their implantation could elicit high bone regeneration and active structural reconstitution. [ABSTRACT FROM AUTHOR]

Background and Objective T and B cells are known to be involved in the disease process of periodontitis. However, the role of natural killer T cells in the pathogenesis of periodontitis has not been clarified. Materials and Methods To examine the role of these cells, C57 BL/6J (wild-type), CD1d−/− and α-galactosylceramide (α GC)-stimulated wild-type mice were orally infected with Porphyromonas gingivalis strain W83. Results Apart from CD1d−/− mice, the level of alveolar bone resorption was elevated by the infection and was further accelerated in α GC-stimulated mice. The infection induced elevated levels of serum amyloid A and P. gingivalis-specific IgG in the sera, although the degree of elevation was much smaller in the CD1d−/− mice. Infection-induced RANKL elevation was only observed in α GC-stimulated mice. Although the cytokines produced by splenocytes were mainly T-helper 1 type in wild-type mice, those in α GC-stimulated mice were predominantly T-helper 2 type. In the liver, the infection demonstrated no effect on the gene expression for interferon-γ, interleukin-4 and RANKL except α GC-stimulated mice in which the infection upregulated the gene expressions. Conclusion This study is the first to show that natural killer T cells upregulated systemic and local inflammatory responses induced by oral infection with P. gingivalis, thereby contributing to the progression of alveolar bone resorption. [ABSTRACT FROM AUTHOR]

Objectives: The retromolar foramen (RMF) is an anatomical structure on the alveolar surface of the retromolar area. This foramen runs consecutive to the retromolar canal (RMC), which diverges from the mandibular canal. It is important to confirm the RMF and canal locations prior to surgical procedures, such as extraction of an impacted molar and bone harvesting as a donor site for bone graft surgery. This aim of this study was to investigate the RMF in Japanese cadaver mandibles using cone-beam computed tomography (CBCT) images and anatomical observations. Methods: Ninety sides of 46 cadaver mandibles were investigated in this study. CBCT images around the retromolar region were acquired for all of the mandibles. The frequency and anteroposterior and buccolingual locations of the RMF were examined on these images. Subsequently, four sides of three mandibles were dissected to confirm the contents of the RMC/RMF. Results: In 24 of 46 (52%) mandibles and 34 of 90 (37%) sides, at least one RMF was observed in the images. In 26 dentate mandibles, 12 (48%) mandibles and 14 (33%) sides presented at least one RMF. The average location of the RMF was 14.4 mm posterior from the distal edge of the second molar. The buccolingual location was 3.0 mm lingual from the mandibular canal. Observations made during the cadaver dissections confirmed that the vessels and nerves diverged from the mandibular canal. Conclusions: The findings suggest that the RMF is not a rare anatomical structure and that practitioners should take this foramen into account in all anesthetic and surgical procedures involving the retromolar area. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The people of the Yayoi period (5th C b.c.–3rd C a.d.), who were the first wet-rice agriculturalists in ancient Japan, had carious lesions that were most frequently located on the root surfaces of their teeth. Root surface exposure is a prerequisite for this type of decay, and alveolar bone loss is the main cause of such exposure. Therefore, we identify the factors associated with root caries, and examine the relationship between root caries and alveolar bone loss in the people of the Yayoi period. Materials and methods: This study was performed using 263 sets of ancient skeletal remains that are believed to be from the Yayoi period and that were excavated at 49 archaeological sites in western Japan. Using 5010 teeth found among the remains, we analysed the relationship between the prevalence of root caries and the cemento-enamel junction–alveolar crest (CEJ–AC) distance. Results: The prevalence of root caries and the mean number of teeth with root caries per person were significantly correlated with age, the presence of coronal caries and the mean CEJ–AC distance per person. We also found that as the mean CEJ–AC distance per tooth surface increased, the percentage of the root surface affected by caries increased. Moreover, after excluding the lingual (palatal) side, the mean CEJ–AC distance per surface was significantly greater for those tooth surfaces with root caries. Conclusion: We present the first evidence that the occurrence of root caries correlated with the CEJ–AC distance in the Yayoi people of Japan. [Copyright &y& Elsevier]

Background: The treatment of periodontal disease in diabetic patients is reported to have a beneficial effect on their glucose control. A recent study indicated that having deep pockets is significantly associated with past development of glucose intolerance in non-diabetic individuals using an oral glucose tolerance test (OGTT). These findings suggest that periodontal disease is a risk factor for diabetes, although more evidence is needed. Methods: A total of 193 Japanese men aged 50 to 54 years with at least 10 teeth were examined as part of a comprehensive health examination before retirement from the Japan Self-Defense Force. Alveolar bone loss of the posterior teeth was measured on a panoramic x-ray film. An OGTT was administered and impaired glucose tolerance (IGT) and diabetes were defined. The relationships between the mean ratio of alveolar bone loss to root length and OGTT results were analyzed after adjusting for known risk factors for diabetes. Results: The proportion of subjects with IGT increased significantly in the subjects with higher tertiles of alveolar bone loss (P <0.05). In the multivariate logistic regression analysis excluding diabetic subjects, the adjusted OR for IGT to normal glucose tolerance (NGT) increased in subjects with higher tertiles of alveolar bone loss (P for trend = 0.03). In the subjects with the highest tertile of alveolar bone loss, the adjusted OR for IGT to NGT was 4.27 (95% confidence interval [CI]: 1.41 to 12.9; P = 0.01). Conclusion: The degree of alveolar bone loss is significantly associated with IGT, suggesting that periodontitis with alveolar bone loss is associated with impaired glucose tolerance. [ABSTRACT FROM AUTHOR]

Background; Moderate elevation of C-reactive protein (CRP) is thought to predict type 2 diabetes and cardiovascular disease (CVD), both of which are associated with periodontitis. Recent studies indicate that periodontal disease is associated with moderate elevation of CRP; however, the relationship between alveolar bone loss (ABL) and CRP elevation is unclear. Methods: A total of 179 Japanese men aged 50 to 34 years old, with at least 10 teeth, were examined as part of a comprehensive health examination before retirement from the Japan Self-Defense Force. ABL was measured at proximal sites of posterior teeth on a panoramic x-ray film. The relationship between the mean ratio of ABL to root length and serum CRP level and other variables was analyzed. Results: ABL was significantly correlated with serum CRP level (P = 0.008), alkaline phosphatase (P = 0.008), high-density lipoprotein (HDL) cholesterol (P = 0.04, inversely), white blood cell count (P <0.001), erythrocyte sedimentation rate (P = 0.002), age (P = 0.03), and smoking history (P <0.001). In a multiple logistic regression model adjusted for age, smoking history, systolic blood pressure, body-mass index, triglyceride, and HDL cholesterol, subjects in the highest tertile of ABL had an increased risk for CRP elevation ≥1.3 mg/l (odds ratio [OR] = 8.20; 95% confidence interval [CI], 1.6 to 40.7; P= 0.01) when compared to the lowest tertile of ABL. Conclusion: ABL around posterior teeth was associated with elevated CRP in Japanese men, suggesting an association between periodontal disease and increased risk of type 2 diabetes and CVD. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse anatomical characteristics of the most posterior alveolar canal (PAC) on computed tomography (CT) images and the posterior superior alveolar foramen (PSAF) physically identified in cadaveric samples, to avoid injuring the posterior superior alveolar artery (PSAA) during surgery in the maxillary tuberosity region. The study included 125 hemi-heads of 64 Japanese cadavers. Simple CT data of the maxillary bone region of the samples were obtained and analysed using measurement software. The alveolar crest (AC) and the PAC were identified to calculate the shortest distance between the AC and the PAC (AC-PAC). Then the samples were dissected to measure physically the shortest distance between the AC and the PSAF (AC-PSAF). The data were analysed statistically. The mean value and standard deviation were 20.7±4.2mm for AC-PAC and 20.7±4.3mm for AC-PSAF. The intraclass correlation coefficient between AC-PAC and AC-PSAF was 0.98. The CT-measured PAC locations were found to be almost identical to the PSAF positions identified physically in the samples. Preoperative CT localization of the PAC aids in avoiding injury to PSAA, while preoperative CT evaluation is important for each case due to significant individual variability in the anatomical PAC and PSAF locations., (Copyright © 2019 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

The purpose of this study was to investigate whether resilient denture liners has the potential to decrease problems affecting the alveolar ridge mucosa during the first adjustment session following the initial fitting of the denture. Interventions were complete denture treatment with permanent acrylic resilient denture liner dentures (RLD) in mandibles and conventional heat-activated acrylic resin dentures (ARD) in mandibles. Maxillary dentures were fabricated with conventional heat-activated ARD. Seventy-four subjects were randomly allocated to the RLD and ARD groups by random permuted blocks within the strata method after obtaining written informed consent. A randomized controlled parallel clinical trial with two hospital centres was conducted from April 2004 to July 2006. The problems were comprehensively evaluated by three outcomes with subjective and objective factors as follows: (i) numbers of sore spots, (ii) duration of wearing dentures and (iii) pain perception with 100 mm Visual Analog Scale. The numbers of sore spots in the mandibular support and border areas for the RLD group were significantly less than those for the ARD groups (P < 0.05). The RLD wearers were able to wear their dentures an additional day longer than the ARD wearers (P < 0.05). The maxillary and mandibular pain ratings for the RLD group were significantly lower than those for the ARD group (P < 0.05). Application of resilient denture liners to mandibular complete dentures provided edentulous patients with fewer problems affecting the alveolar during the first adjustment session following the initial fitting of the denture when compared with conventional denture treatments.

Cleavage lines were experimentally reproduced in the oral mucosa of Japanese cadavers. They were investigated macroscopically and histologically. The reproduced cleavage lines showed little directional variation by sex or age. From the histological findings, the mucosal cleavage lines were interpreted to represent cleavage split along the direction of connective tissue fibres in the lamina propria.