Clinical evaluation of bone quality of particulate cancellous bone and marrow, and implant prosthetic rehabilitation

This study aimed to subjectively evaluate bone quality in the particulate cancellous bone and marrow (PCBM) graft area and to assess the survival rates of implants. A retrospective review was conducted based on patient age, sex, diagnosis, reconstructed site, number of implants, prosthetic type, and duration of follow-up. Images from computed tomography (CT) before implant insertion were obtained and used in this study. We selected a 4.0-mm diameter × 8.0-mm length region of interest in the implant placement area, and measured the CT attenuation value. No significant correlations were seen between CT attenuation values and implant survival rates in the maxilla and mandible. On the other hand, CT attenuation values and implant survival rates were significantly lower in patients with malignancy than in non-malignant cases. Placing implants in PCBM grafted bone requires a full understanding of bone quality before surgery and drilling to ensure primary stability, along with consideration of soft tissue management and maintenance programs.

Salivary metabolites as potential predictive biomarkers for lung surgery complications: a retrospective cross-sectional study

PURPOSE

Saliva is often used as a tool for identifying systemic diseases because of the noninvasive nature of its collection. Moreover, salivary metabolites can be potential predictive factors for postoperative survival. We conducted the present study to establish whether salivary metabolites can function as predictive biomarkers for lung surgery complications.

METHODS

Unstimulated salivary samples were collected from 412 patients before lung surgery. Salivary metabolites were analyzed comprehensively by capillary electrophoresis mass spectrometry. Clinical data with the discriminatory ability of biomarkers were assessed to predict lung surgery complications using multivariate logistic regression analysis. The primary endpoint was the risk factors for postoperative complications of Clavien-Dindo grade ≥ III.

RESULTS

Postoperative complications of Clavien-Dindo grade ≥ III developed in 36 patients (8.7%). There was no postoperative 30-day mortality. Male sex (odds ratio [OR], 3.852; 95% confidence interval CI 1.455-10.199; p = 0.007) and salivary gamma-butyrobetaine (OR, 0.809; 95% CI 0.694-0.943; p = 0.007) were identified as significant risk factors for postoperative complications of Clavien-Dindo grade ≥ III.

CONCLUSION

Salivary metabolites are potential noninvasive biomarkers for predicting postoperative complications of lung surgery.

Factors influencing delayed referral of oral cancer patients from family dentists to the core hospital

Background/purpose

Most oral cancer (OC) cases are identified by family dentists in Japan. However, a significant number of patients with OC in Japan are referred to core hospitals at advanced stages. Therefore, identifying the factors that contribute to delayed referrals from family dentists to core hospitals is crucial for detecting OC in its earlier stages. The aim of this retrospective study was to identify the risk factors for referral delays from family dentists to core hospitals.

Materials and methods

The study included 63 patients with OC who were referred by family dentists to the Yamagata University Hospital between 2010 and 2022. The clinical parameters related to referral delays were retrospectively investigated using letters of reference provided by the family dentists and patient charts. Backward multiple regression analysis was performed to identify the relationships between the length of referral delay and potential risk factors. Additionally, backward multivariate logistic regression analysis was performed to examine the independent association between referral delays of >4 weeks and several clinical parameters.

Results

Multiple regression analysis revealed that misdiagnosis of malignant lesions by family dentists (P = 0.047) was significantly associated with longer referral delays. Additionally, misdiagnosis of malignant lesions by family dentists was also an independent risk factor for referral delays of >4 weeks (odds ratio, 10.387; P = 0.006).

Conclusion

Misdiagnosis of malignant lesions by family dentists was a significant risk factor for referral delays from family dentists to core hospitals. Our results will motivate family dentists to improve their ability to diagnose OC.

Synergistic effect of zoledronate and compressive force suppresses proliferation and differentiation of human gingival fibroblasts

We investigated the effects of zoledronate (ZA) and compressive force, separately and in combination, on the proliferation and differentiation of human gingival fibroblasts (HGFs) to verify the mechanism underlying medication-related osteonecrosis of the jaw (MRONJ). The addition of 100 µM ZA markedly inhibited cell proliferation. Expression of type I collagen, fibroblast growth factor 2, and connective tissue growth factor genes, was decreased by ZA and compressive force. Similar results were observed for collagen expression by using Sirius red staining. These results, together with clinical findings that MRONJ is more common in cases with excessive mechanical stress on the oral mucosa, suggest that bisphosphonates such as ZA and mechanical stress may act in conjunction as risk factors for the development of MRONJ by affecting homeostasis of the oral mucosal tissues, including HGFs.

Associations between subjective well-being, number of teeth, and self-rated mastication in Japanese adults: A cross-sectional study

This cross-sectional study aimed to investigate the risk factors for low levels of subjective well-being (SWB) in the general population of Japan, specifically, the impact of the number of teeth and self-rated mastication. The surveyed population consisted of individuals aged between 40 and 79 years from Yamagata prefecture, Japan. A postal self-administered questionnaire survey of respondents lifestyles, medical history, oral health, and dietary intake, was conducted from 2017 to 2021. We included 6846 participants to confirm the independent associations between SWB and several parameters using multivariate ordinal logistic regression analysis to estimate adjusted odds ratios and 95% confidence intervals. Individuals with < 20 teeth and poor mastication ability had a 1.3-fold risk for low levels of SWB compared with individuals with ≥ 20 teeth with good mastication ability (adjusted odds ratios = 1.300, 95% confidence intervals = 1.043-1.621, P = .020). There were no differences between individuals with good mastication ability, regardless of the number of remaining teeth. Our study emphasizes not only the importance of having ≥ 20 teeth and good mastication ability for high levels of SWB but also the importance of restoring mastication ability using some form of prosthesis, to facilitate a high level of SWB when the number of remaining teeth is < 20.

Salivary metabolomics for oral leukoplakia with and without dysplasia

PURPOSE

Oral leukoplakia (OL) is a common potentially malignant oral disorder. Therefore, there is a need for simple screening methods for OL before its transformation into oral cancer. Furthermore, because invasive open biopsy is the sole method to determine if an OL lesion is dysplastic, there is also a clinical need for non-invasive methods to differentiate dysplastic OL from non-dysplastic OL. This study aimed to identify salivary metabolites that can help differentiate patients with OL from healthy controls (HC) and also dysplastic OL from non-dysplastic OL.

MATERIAL & METHODS

Whole unstimulated saliva samples were collected from patients with OL (n = 30) and HCs (n = 29). The OL group included nine patients with dysplastic OL and 20 with non-dysplastic OL. Hydrophilic metabolites in the saliva samples were comprehensively analyzed through capillary electrophoresis mass spectrometry. To evaluate the discrimination ability of a combination of multiple markers, a multiple logistic regression (MLR) model was developed to differentiate patients with OL from HCs and dysplastic OL from non-dysplastic OL.

RESULTS

Twenty-eight metabolites were evidently different between patients with OL and HCs. Finally, three metabolites (guanine, carnitine, and N-acetylputrescine) were selected to develop the MLR model, which resulted in a high area under curve (AUC) of the receiver operating characteristic (ROC) to differentiate patients with OL from HCs (AUC = 0.946, p < 0.001, 95% confidential interval [CI] = 0.889- 1.000). Similarly, two metabolites were evidently different between patients with dysplastic and non-dysplastic OL. Finally, only one metabolite (7-methylguanine) was selected in the MLR model, which revealed a moderate discrimination ability for dysplastic and non-dysplastic OL (AUC = 0761, p = 0.027, 95% CI = 0.551-0.972).

CONCLUSION

Our candidate salivary metabolites showed potential not only to discriminate OL from HC, but also to discriminate dysplastic OL from non-dysplastic OL.

Association of health behaviors, dietary habits, and oral health with weight gain after 20 years of age in community-dwelling Japanese individuals aged 40 years and older: a cross-sectional study

OBJECTIVES

This cross-sectional study investigated the factors associated with weight gain ≥ 10 kg after 20 years of age in the general Japanese population, with a focus on the number of teeth.

MATERIALS AND METHODS

We included individuals aged ≥ 40 years from Yamagata prefecture, Japan from 2017-2021. A postal survey was conducted using a self-administered questionnaire; 5,940 participants were included in the final analysis. The questionnaire included items on lifestyle factors, medical history, physical and mental conditions, oral health, and dietary intake. A multivariate logistic regression analysis was used to identify independent associations between weight gain ≥ 10 kg after 20 years of age and various parameters; adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated.

RESULTS

Less than 20 teeth, male sex, drinking habit frequency, eating very fast or fast, and a higher frequency of eating-away-from-home were significant factors associated with weight gain ≥ 10 kg after 20 years of age; individuals with < 20 versus > 20 teeth exhibited a 1.35-fold higher OR (95% CI 1.15-1.59; p < 0.01).

CONCLUSIONS

Our results suggest that having < 20 teeth may affect weight gain ≥ 10 kg after 20 years of age. However, owing to the cross-sectional study design, causality could not be determined. Therefore, maintaining healthy lifestyle behaviors to avoid tooth loss may also affect weight gain ≥ 10 kg after 20 years of age.

CLINICAL RELEVANCE

Having < 20 teeth has the potential to affect long-term weight gain after 20 years of age.

Usefulness of powdered crown of mandibular first premolars in birth year estimation by radiocarbon dating

BACKGROUND

Radiocarbon (14C), whose levels increased in the atmosphere between 1955 and 1963, accumulates in the enamel of human teeth only during the process of tooth formation and has been applied to estimate the birth year of unidentified corpses. However, enamel isolation from teeth is time-consuming and labor-intensive. Therefore, this study aimed to estimate the birth year using 14C in the crown of a single mandibular first premolar tooth.

MATERIALS AND METHODS

Fourteen mandibular first premolars collected from forensic autopsies were analyzed. For nine teeth, each tooth was cut longitudinally: half of the tooth was enamel, and the other half was crown (1). For the other five teeth, the entire crown was used (2). Thereafter, the 14C concentration in each tooth was measured using accelerator mass spectrometry.

RESULTS

The absolute error between the actual date of birth (DOB) and the estimated DOB was within the range of 1.0-8.8 years in the enamel of five teeth and 0.1-4.0 years in the crown halves of seven teeth (1). For the five teeth with entire crowns, the absolute errors ranged between 0.3 and 3.0 years (2).

CONCLUSION

The absolute error of 14C-based year of birth estimation using the powdered crown of the mandibular first premolar teeth ranged between 0.1 and 4.0 years. Our method, which involves pulverizing an entire crown, eliminates the need for the equipment, time, and labor associated with enamel isolation. Therefore, 14C dating using powdered crowns of mandibular premolars can be useful for birth year estimation.

Measures of oral health-related quality of life in patients with bone graft and implant prosthetic rehabilitation at the anterior of mandible/maxilla among young and middle-aged adults: a retrospective pilot study

OBJECTIVES

Dental implants are believed to contribute to improved masticatory function and oral health-related quality of life (OHRQOL), but the details remain unclear. The aim of this study was to evaluate the clinical outcomes of dental implant prosthetic rehabilitation after bone graft at the anterior mandible/maxilla based on OHRQOL, particularly in young and middle-aged patients.

METHODS

This retrospective study included 11 patients who received bone grafts at the anterior mandible/maxilla and dental implant surgery. Chewing function score and OHRQOL (using the Oral Health Impact Profile-14 questionnaire) were evaluated before and after completion of an implant-retained bridge or removable implant-supported denture.

RESULTS

Chewing function score tended to improve slightly after dental implant prosthetic rehabilitation, but none of the observed differences were significant. In the assessment of OHRQOL, relatively worse domain scores before completion of dental implant prosthetic rehabilitation were seen for Functional limitation, Psychological discomfort, and Psychological disability. Conversely, Social disability seemed relatively unaffected by tooth loss. All domain scores and total scores for items other than Physical disability and Social disability were significantly improved after completion of dental implant rehabilitation.

CONCLUSIONS

Tooth loss in the anterior region may not significantly affect chewing function score, but can have a significant impact on OHRQOL. Bone grafts and dental implant prosthetic rehabilitation can resolve these problems, and the results of this study will benefit both patients and medical professionals in terms of treatment planning and informed consent.

Analgesic effect of a lidocaine-ropivacaine mixture for extraction of impacted mandibular third molars: a randomized controlled trial

OBJECTIVES

The painless postoperative period can be significantly prolonged by using long-acting local anesthetics such as ropivacaine, though these local anesthetics are known for their slower onset of action. To compensate for this, a mixture of short-onset (e.g., lidocaine) and long-acting local anesthetics is used. However, the efficacy of such an anesthetic cocktail has not been elucidated in the field of oral and maxillofacial surgery.

MATERIALS AND METHODS

To address the research purpose, this prospective randomized controlled trial included 56 patients scheduled for impacted mandibular third molar extraction. All patients received the inferior alveolar nerve block (IANB) using either 2% lidocaine with epinephrine or a 1:1 mixture of 2% lidocaine with epinephrine and 0.75% ropivacaine.

RESULTS

Patients anesthetized using the lidocaine-ropivacaine mixture showed significantly prolonged postoperative analgesia and pain control than those anesthetized using lidocaine only.

CONCLUSIONS

IANB using a lidocaine-ropivacaine mixture can provide prolonged postoperative anesthesia and pain control with extraction of mandibular third molars.

CLINICAL RELEVANCE

This method can be a noteworthy addition to existing methods of local anesthesia for the extraction of mandibular third molars. Trial registration number University Hospital Medical Information Network (No. UMIN000044315).

Evaluation of radiographic characteristics and surgical removal of 147 mesiodens

The aim of this study was to evaluate the radiographic characteristics and surgical removal of mesiodens among patients who had attended the Department of Dentistry, Oral and Maxillofacial-Plastic and Reconstructive Surgery of the Faculty of Medicine, Yamagata University. This study included 121 patients in the final analysis. We retrospectively reviewed medical records including patient age, sex, mesiodens number, direction, position, opportunity for detection, surgical approach and operating time. The 121 patients comprised 82 males and 39 females. Mean age was 7.6 ± 3.1 years (range, 4-35 years). The total number of mesiodens among these 121 patients was 147. Ninety-six patients had one mesiodens, 24 patients had two mesiodens and 1 patient had 3 mesiodens. Seventy-nine mesiodens were detected while taking X-rays for routine dental examination and/or orthodontic treatment at their family dental/orthodontic clinic. Mean operating time for removal of the 147 mesiodens was 32.2 ± 18.1 min. Among the 96 patients with one mesiodens, mean operating time for removal of the mesiodens was 30.7 ± 16.5 min. Operating time for removal of a mesiodens tended to be prolonged with increased distance from the alveolar crest. Early detection of mesiodens on routine radiographic check-ups and surgical planning considering patient age, crown direction, position of the mesiodens will contribute to improved treatment of mesiodens.

Reconstruction After Hemimandibulectomy With a Plate and Soft-Tissue Free Flap Followed by a Titanium Mesh and Particulate Cancellous Bone and Marrow Harvested From Bilateral Posterior Ilia: A Case Report

A particulate cancellous bone and marrow (PCBM) graft combined with titanium (Ti-) mesh tray has become one of the most popular mandibular reconstruction methods. The technique has been applied to the mandibular discontinuity defects after segmental mandibulectomy. To the best of our knowledge, there are no reports on using the technique after hemimandibulectomy, during which a wide mandibular resection, including the condyle, is performed. Here, we first report a case of mandibular reconstruction after hemimandibulectomy, using a plate and soft-tissue free flap, followed by a Ti-mesh and PCBM harvested from the bilateral posterior ilia, which was successful. This case report first revealed how bone resorption occurred clinically in mandibular reconstruction using PCBM and Ti-mesh tray after hemimandibulectomy. We also revealed the high predictability of the mandibular reconstruction using PCBM and Ti-mesh tray after hemimandibulectomy. Our report also provides a guiding principle to overcome the limitation of mandibular reconstruction using PCBM and Ti-mesh tray after hemimandibulectomy. However, our manuscript has limited evidence, being a case report.

Association between the duration of antibiotic prophylaxis and surgical site infection after orthognathic surgery in Japan

PURPOSE

This study aimed to evaluate the risk factors for surgical site infection (SSI) after orthognathic surgery, focusing on the duration of prophylactic antibiotic administration in Japan.

STUDY DESIGN

The study included 181 patients who underwent orthognathic surgery at the Department of Oral and Maxillofacial Surgery of Yamagata University Hospital between 2012 and 2021. The clinical parameters of SSI were retrospectively investigated using patient charts. Logistic regression analysis was used to estimate the odds ratios (ORs) with 95% confidence intervals (CIs) for risk factors for SSI after orthognathic surgery.

RESULTS

Nineteen patients (10.5%) were complicated with SSI. Male sex (OR, 3.638; 95% CI, 1.316-10.058) and an antibiotic prophylaxis duration ≤3 days (OR, 12.718; 95% CI, 1.639-98.673) were independent risk factors for SSI after orthognathic surgery.

CONCLUSION

Extended-term antibiotic prophylaxis was more effective for prevention of SSI after orthognathic surgery than short-term in this study.

Protocol for a multicentre, prospective observational study of elective neck dissection for clinically node-negative oral tongue squamous cell carcinoma (END-TC study)

INTRODUCTION

In early-stage oral tongue squamous cell carcinoma (OTSCC), elective neck dissection (END) is recommended when occult lymph node metastasis is suspected; however, there is no unanimous consensus on the risks and benefits of END in such cases. The management of clinically node-negative (cN0) OTSCC remains controversial. This study, therefore, aimed to evaluate the efficacy of END and its impact on the quality of life (QoL) of patients with cN0 OTSCC.

METHODS AND ANALYSIS

This is a prospective, multicentre, nonrandomised observational study. The choice of whether to perform END at the same time as resection of the primary tumour is based on institutional policy and patient preference. The primary endpoint of this study is 3-year overall survival. The secondary endpoints are 3-year disease-specific survival, 3-year relapse-free survival and the impact on patient QoL. Propensity score-matching analysis will be performed to reduce selection bias.

ETHICS AND DISSEMINATION

This study was approved by the Clinical Research Review Board of the Nagasaki University. The protocol of this study was registered at the University Hospital Medical Information Network Clinical Trials Registry. The datasets generated during the current study will be available from the corresponding author on reasonable request. The results will be disseminated internationally, through scientific and professional conferences and in peer-reviewed medical journals.

TRIAL REGISTRATION NUMBER

UMIN000027875.

Salivary Metabolomics for Prognosis of Oral Squamous Cell Carcinoma

This study aimed to identify salivary metabolomic biomarkers for predicting the prognosis of oral squamous cell carcinoma (OSCC) based on comprehensive metabolomic analyses. Quantified metabolomics data of unstimulated saliva samples collected from patients with OSCC (n = 72) were randomly divided into the training (n = 35) and validation groups (n = 37). The training data were used to develop a Cox proportional hazards regression model for identifying significant metabolites as prognostic factors for overall survival (OS) and disease-free survival. Moreover, the validation group was used to develop another Cox proportional hazards regression model using the previously identified metabolites. There were no significant between-group differences in the participants’ characteristics, including age, sex, and the median follow-up periods (55 months [range: 3–100] vs. 43 months [range: 0–97]). The concentrations of 5-hydroxylysine (p = 0.009) and 3-methylhistidine (p = 0.012) were identified as significant prognostic factors for OS in the training group. Among them, the concentration of 3-methylhistidine was a significant prognostic factor for OS in the validation group (p = 0.048). Our findings revealed that salivary 3-methylhistidine is a prognostic factor for OS in patients with OSCC.

Differential diagnosis of lung cancer and benign lung lesion using salivary metabolites: A preliminary study

Background

Saliva is often used as a biomarker for the diagnosis of some oral and systematic diseases, owing to the non‐invasive attribute of the fluid. In this study, we aimed to identify salivary biomarkers for distinguishing lung cancer (LC) from benign lung lesion (BLL).

Materials and Methods

Unstimulated saliva samples were collected from 41 patients with LC and 21 with BLL. Salivary metabolites were comprehensively analyzed using capillary electrophoresis mass spectrometry. To differentiate between patients with LCs and BLLs, the discriminatory ability of each biomarker was assessed. Furthermore, a multiple logistic regression (MLR) model was developed for evaluating discriminatory ability of each salivary metabolite.

Results

The profiles of 10 salivary metabolites were remarkably different between the LC and BLL samples. Among them, the concentration of salivary tryptophan was significantly lower in the samples from patients with LC than in those from patients with BLL, and the area under the curve (AUC) for discriminating patients with LC from those with BLL was 0.663 (95% confidence interval [CI] = 0.516–0.810, p = 0.036). Furthermore, from the MLR model developed using these metabolites, diethanolamine, cytosine, lysine, and tyrosine, were selected using the back‐selection regression method. The MLR model based on these four metabolites had a high discriminatory ability for patients with LC and those with BLL (AUC = 0.729, 95% CI = 0.598–0.861, p = 0.003).

Conclusion

The four salivary metabolites can serve as potential non‐invasive biomarkers for distinguishing LC from BLL.

Therapeutic effect of a novel curcumin derivative GT863 on a mouse model of amyotrophic lateral sclerosis

The present study investigated the therapeutic effects of the curcumin derivative 3-[(1E)-2-(1H-indol-6-yl)ethenyl]-5-[(1E)-2-[2-methoxy-4-(2-pyridylmethoxy)phenyl]ethenyl]-1H-pyrazole (GT863) in amyotrophic lateral sclerosis (ALS). The inhibitory effect of GT863 on superoxide dismutase 1 (SOD1) aggregation was evaluated in cell-free assays. GT863 interfered with the conformational changes of the SOD1 protein and later, oligomeric aggregation. Furthermore, its antioxidant, anti-inflammatory, and neuroprotective effects were evaluated in cell-free and cultured cell assays. GT863 inhibited H₂O₂- and glutamate-induced cytotoxicity and activated an antioxidant responsive element pathway. Additionally, in vivo effects of GT863 in the ALS mice model were evaluated by its oral administration to H46R mutant SOD1 transgenic mice. Rotarod test showed that GT863 administration significantly slowed the progression of motor dysfunction in the mice. In addition, GT863 substantially reduced highly-aggregated SOD1, further preserving large neurons in the spinal cord of GT863-treated mice. Collectively, these results indicated that GT863 could be a viable therapeutic agent with multiple vital actions for the treatment of ALS.

Bone marrow space volume of the mandible influencing intraoperative blood loss in bilateral sagittal split osteotomy: A pilot Study

The aim of this study was to investigate whether the bone marrow space volume of the mandible affects blood loss during bilateral sagittal split osteotomy (BSSO). Sixteen patients who underwent BSSO in our hospital were included in this study. Bone marrow space volume of the mandible was measured by analyzing images from computed tomography. Blood loss during BSSO was measured by weighing gauze, measuring suctioned blood, and adjusting for the volume of irrigation solution used during BSSO. Mean blood loss during BSSO for the 16 patients was 200.5 ml, and patients were divided into: Group I, with less than mean blood loss; and Group II, with greater than mean blood loss. Total bone marrow space volume was significantly greater in Group II (12,450.7 ± 2644.3 mm³) than in Group I (9130.3 ± 3005.8 mm³; P<0.05). A correlation between bone marrow space volume and blood loss during BSSO was suggested, and these results are beneficial for surgeons planning and preparing the orthognathic surgery.

Identification of Salivary Proteomic Biomarkers for Oral Cancer Screening

BACKGROUND/AIM

The current study aimed to identify biomarkers for differentiating between patients with oral cancer (OC) and healthy controls (HCs) on the basis of the comprehensive proteomic analyses of saliva samples by using liquid chromatography-mass spectrometry (LC-MS/MS).

PATIENTS AND METHODS

Unstimulated saliva samples were collected from 39 patients with OC and from 31 HCs. Proteins in the saliva were comprehensively analyzed using LC-MS/MS. To differentiate between patients with OC and HCs, a multiple logistic regression model was developed for evaluating the discriminatory ability of a combination of multiple markers.

RESULTS

A total of 23 proteins were significantly differentially expressed between the patients with OC and the HCs. Six out of the 23 proteins, namely α-2-macroglobulin-like protein 1, cornulin, hemoglobin subunit β, Ig k chain V-II region Vk167, kininogen-1 and transmembrane protease serine 11D, were selected using the forward-selection method and applied to the multiple logistic regression model. The area under the curve for discriminating between patients with OC and HCs was 0.957 when the combination of the six metabolites was used (95% confidence interval=0.915-0.998; p<0.001). Furthermore, these candidate proteins did not show a stage-specific difference.

CONCLUSION

The results of the current study showed that six salivary proteins are potential non-invasive biomarkers for OC screening.

High Parity Is an Independent Risk Factor for Tooth Loss in Women: A Community-Based Takahata Study in Japan

Risk factors for tooth loss have been widely examined previously. However, no previous study has comprehensively investigated the risk factors, including lifestyle-related specific factors (parity, oral health habits, and socioeconomic status), for fewer than 20 teeth among women in the general population in Japan. This cross-sectional study explored the association of these risk factors, especially parity, with having fewer than 20 teeth among Japanese women. A self-reported questionnaire including items on lifestyle-related risk factors (parity, oral health, diet [e.g., alcohol and sucrose consumption]) and socioeconomic status was sent by post to female residents (age ≥ 40 years) of Takahata town, Yamagata Prefecture, in 2005. Multivariate logistic regression analysis including 3,854 eligible participants was performed to investigate the association between various factors (including parity) and having fewer than 20 teeth. The results indicated that, compared with nulliparous women, women with two, three, and four completed pregnancies had 2.485-, 2.844-, and 4.305-fold increased risk of having fewer than 20 teeth, respectively. Our study is the largest-scale study of the general female population in Japan and the first study to comprehensively investigate risk factors (parity, oral health status, and socioeconomic status) for fewer than 20 teeth. We thus found that higher parity, especially, two or more, was independent risk factors for having less than 20 teeth among Japanese women. In conclusion, the present study emphasizes the importance of good oral health habits in women, especially, during pregnancy and in the postpartum period, to maintain 20 or more teeth.

Association between presence of 20 or more natural teeth and all-cause, cancer-related, and cardiovascular disease-related mortality: Yamagata (Takahata) prospective observational study

BACKGROUND

Several studies have surveyed the relationship between the presence of ≥ 20 natural teeth and mortality. However, very few have evaluated this association over a long-term follow-up of more than ten years within a large population in Japan. This study aimed to prospectively confirm the associations between mortality and the presence of ≥ 20 natural teeth within a community-based population in Japan.

METHODS

A prospective observational study including 2208 participants aged ≥ 40 years was conducted in Takahata Town, Japan, between May 2005 and December 2016. All participants answered a self-administered questionnaire to provide their background characteristics, including their number of teeth. The participants were classified into two categories based on their self-reported number of teeth (< 20 and ≥ 20 teeth). Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional-hazards regression model to assess risk factors for all-cause, cancer-, and cardiovascular disease-related mortality.

RESULTS

The total follow-up period was 131.4 ± 24.1 months (mean ± SD). After adjusting for covariates, the risk of all-cause mortality was significantly higher in the group with < 20 teeth than in those with ≥ 20 teeth (HR = 1.604, 95% CI 1.007-2.555, p = 0.047). However, the risk of cancer- and cardiovascular disease-related mortalities was not statistically significant between the two groups.

CONCLUSION

In this study, participants with < 20 teeth had a significantly higher risk of all-cause mortality, although the difference was borderline significant. These results emphasize the importance of having ≥ 20 natural teeth for a healthy life expectancy.

A case of myeloid sarcoma of the mandibular gingiva as extramedullary relapse of acute myeloid leukemia

PURPOSE

Myeloid sarcoma (MS) is defined as a tumorous mass of myeloblasts or immature myeloid cells involving an extramedullary anatomic site. MS occurs in 3 to 8% of patients with acute myeloid leukemia. The overwhelming majority of MS occurs in the skin, bones, and gastrointestinal tract; intraoral MS (IMS) is extremely rare.

METHODS

We describe a case of MS of the mandibular gingiva in a patient with acute myeloid leukemia that was in remission. We also present a review of the English and Japanese literature with a special focus on the management and prognosis of intraoral MS.

RESULTS

The patient was discharged while in remission 8 months after the initial examination.

CONCLUSION

The prognosis of IMS is extremely poor in general, and a diagnostic delay can prevent adequate therapy by hematologists and oncologists. All dental clinicians must keep the possibility of IMS in mind and carefully examine all patients with AML.

Clinical study of octacalcium phosphate and collagen composite in oral and maxillofacial surgery

Octacalcium phosphate and its collagen composite have been recognized as bone substitute materials possessing osteoconductivity and biodegradation properties. We evaluated the effectiveness of octacalcium phosphate and its collagen composite used for bone augmentation in major oral and maxillofacial surgeries in a clinical trial. Octacalcium phosphate and its collagen composite were used in cases of sinus floor elevation in 1- and 2-stage, socket preservation, cyst, and alveolar cleft procedures. A total of 60 patients were evaluated for effectiveness after the implantation of octacalcium phosphate and its collagen composite. Although sinus floor elevation in 1-stage, cyst, and alveolar cleft cases met the criteria for the judgment of success, sinus floor elevation in 2-stage and socket preservation groups did not meet the criteria in the initial evaluation. However, an additional evaluation for reconfirmation revealed the effectiveness of octacalcium phosphate and its collagen composite in those groups, and all evaluation results ultimately indicated the success of this clinical trial. Therefore, this clinical trial suggested that application of octacalcium phosphate and its collagen composite for oral and maxillofacial surgery was safe and effective and that octacalcium phosphate and its collagen composite could be a bone substitute candidate instead of autologous bone.

Evaluation of a Semi-Solidifying Liquid Formula for Nasogastric Tube Feeding After Oral and Maxillofacial Surgery

PURPOSE

The aim of this retrospective study was to evaluate a semi-solidifying liquid formula for nasogastric tube (NGT) feeding after oral and maxillofacial surgery.

MATERIALS AND METHODS

In total, 42 patients who underwent oral and maxillofacial surgery for malignant tumors, benign tumors, jaw reconstruction, or jaw fractures received postoperative NGT feeding for nutritional control between 2013 and 2019. Of these patients, 21 received a liquid diet (liquid group; administration rate, 100 mL/hour) and 21 received a semi-solidifying liquid formula (semisolid group [SSG]; administration rate, 400 mL/hour; Mermed Plus; Terumo, Tokyo, Japan). We retrospectively evaluated the complications of NGT feeding in both groups.

RESULTS

During the course of NGT feeding, the incidence of abdominal pain (P = .022), rate of probiotic prescription for diarrhea (P = .012), and Bristol stool form scale score (P = .014) were significantly lower in the SSG than in the liquid group. The maximum defecation frequency per day was also lower in the SSG, although the difference was not significant (P = .069).

CONCLUSIONS

Overall, the semi-solidifying formula was associated with a higher administration rate and a lower incidence of gastrointestinal complications. These findings will help oral and maxillofacial surgeons in the selection of appropriate diets for postoperative NGT feeding.

Discrimination of oral squamous cell carcinoma from oral lichen planus by salivary metabolomics

OBJECTIVE

This study was conducted to distinguish salivary metabolites in oral squamous cell carcinoma (OSCC) from those in oral lichen planus (OLP) to identify practical biomarkers for the discrimination of OSCC from OLP.

SUBJECTS AND METHODS

Whole unstimulated saliva samples were collected from patients with OSCC (n = 34) and OLP (n = 26). Hydrophilic metabolites in the saliva samples were comprehensively analysed by capillary electrophoresis mass spectrometry. To evaluate the discrimination ability of a combination of multiple markers, a multiple logistic regression (MLR) model was developed to differentiate OSCC from OLP.

RESULTS

Fourteen metabolites were found to be significantly different between the OSCC and OLP groups. Among them, indole-3-acetate and ethanolamine phosphate were used to develop the MLR model. The combination of these two metabolites showed a high area under the receiver operating characteristic curve (0.856, 95% confidential interval: 0.762-0.950; p < .001) for discriminating OSCC from OLP.

CONCLUSIONS

We identified salivary metabolites for discerning between OSCC and OLP, which is clinically important for detecting the malignant transformation of OLP by both dentists and oral surgery specialists. Our candidate salivary metabolites show potential for non-invasive screening of OSCC versus OLP.

Tooth Loss-associated Cognitive Impairment in the Elderly: A Community-based Study in Japan

Objective Dementia is a major cause of disruption for a healthy life expectancy in Japan. It has been suggested that the number of teeth is a modifiable risk factor for cognitive impairment and dementia. We therefore examined the possible association between the cognitive function and the number of natural and artificial teeth in community-dwelling Japanese elderly individuals. Methods Among the participants in our prospective, community-based study, 210 elderly individuals (103 men and 107 women; 78.1±4.9 years; mean age±standard deviation) underwent both dental examinations and a Mini-Mental State Examination (MMSE), as well as various medical checkups, in 2016 and 2017. Results The number of natural teeth was significantly associated with an individual's MMSE score. The percentage of cognitively normal subjects (MMSE scores: 27-30) decreased significantly with a decrease in the number of natural teeth. Among the MMSE items, the calculation ability was significantly and independently associated with the number of natural teeth. Regression was calculated as the predicted score of MMSE =21+0.3× (years of schooling) +0.1× (number of natural teeth). Among individuals with 19 or fewer natural teeth, those who had a total of 20 teeth or more, including both natural and artificial teeth, had significantly higher MMSE scores than those who had 19 or fewer natural and artificial teeth combined. Conclusion The number of natural teeth was significantly associated with the cognitive function, especially the calculation ability, and the use of artificial teeth was associated with the preservation of the cognitive function in community-dwelling elderly individuals.

Estimation of birth year by radiocarbon dating of tooth enamel: Approach to obtaining enamel powder

Atmospheric radiocarbon (¹⁴C) levels increased from 1955 to 1963 due to atmospheric nuclear weapon tests, and then decreased. As ¹⁴C accumulates in human tooth enamel while the enamel is being formed, ¹⁴C can be used to estimate the birth year of unidentified bodies. Measurement results of ¹⁴C content in tooth enamel using accelerator mass spectrometry vary depending on the enamel's sample site. To address this problem, a method for equalizing samples using a pulverizer was considered in this study. Regarding the tube and cone used as the pulverizer, (1) a polycarbonate tube and stainless steel cone, (2) a stainless steel tube and cone, and (3) a tungsten carbide tube and cone, were compared. In (1), the modern carbon ratio was approximately half that of the normal ratio of 100 pMC, with which accurate dating was impossible, and in (2), a high background value was obtained for IAEA-C1, which was pulverized using a reusable tube and cone. In (3), the ¹⁴C content for IAEA-C1 pulverized using reusable tube and cone, which was washed with quartz sand, was 0.31 ± 0.01 pMC. This result did not show any problems regarding background value. Therefore, the use of tungsten carbide products and washing with quartz sand is recommended for ¹⁴C measurement of pulverized teeth.

A case of multiple osseous choristomas arising on the medial side of the lateral pterygoid muscle

Osseous choristoma is a rare entity in the oral and maxillofacial region. The most common site is the tongue, followed by the buccal mucosa. Osseous choristoma of the muscle is unusual and few cases have been described in the literature. No reports have described osseous choristoma arising on the medial side of the lateral pterygoid muscle. Herein, we report the first such case. A 61-year-old woman was referred to our facility for treatment of temporomandibular joint disorder. Computed tomography (CT) revealed two osseous lesions on the medial side of the lateral pterygoid muscle. Preoperatively, a three-dimensional (3D) life-sized model of the skull was fabricated from the CT imaging data. The 3D skull model was used to clarify the 3D positional relationships of the osseous lesions relative to the surrounding anatomical structures. Surgery to remove the osseous lesions was performed under general anesthesia. Unfortunately, only the larger of the two masses was able to be resected because of the risk of nerve and vascular injury. Histological examination revealed that the resected lesion comprised mature lamellar bone with regular osteocytes and no atypia. The diagnosis was multiple osseous choristomas based on the histological and clinical findings.

Fewer teeth are a risk factor for being underweight in community-dwelling Japanese aged 40 years and older: The Yamagata (Takahata) Study

OBJECTIVE

The aim of the present study was to investigate comprehensively, the risk factors for underweight in cross-sectional study in the general population of Japan.

METHODS

The survey population was the general population of individuals aged >40 years in Takahata town, Japan in 2005. A postal survey in the form of a self-administered questionnaire was distributed, and 6084 individuals were entered into the final statistical analysis. The self-administered questionnaire contained items regarding lifestyle, oral health status, socio-economic status and dietary intake. To examine the independent relationships between an underweight status and several parameters, a multivariate logistic regression analysis was used to estimate adjusted odds ratios (ORs).

RESULTS

The number of teeth, age, alcohol consumption, hypertension, spousal status, smoking habit, appetite, body weight at 20 years of age, habit of going out and physical activity were independently associated with an underweight status compared with the normal weight group. Individuals with fewer than 10 teeth were especially more likely to be underweight than individuals with more than 20 teeth (OR = 1.956, 95% CI = 1.261-3.035).

CONCLUSION

This study showed an independent association between the number of teeth and an underweight status, indicating that fewer teeth can increase the risk of being underweight.

Comparison of Complications With Semisolid Versus Liquid Diet Via Nasogastric Feeding Tube After Orthognathic Surgery

PURPOSE

The aim of this retrospective study was to compare the effectiveness of nasogastric tube (NGT) feeding of a semisolid diet versus a liquid diet after orthognathic surgery.

PATIENTS AND METHODS

The orthognathic surgery patients were relatively young and generally healthy, without severe medical disease. Of the patients, 26 received liquid feeding (liquid diet group [LG], with an administration rate of 100 mL/hour), 30 received semisolid feeding at a high administration rate (semisolid diet-rapid administration group [SSRAG], 200 to 500 mL/hour), and 33 received semisolid feeding at a slower rate (semisolid diet-slow administration group [SSSAG], 100 mL/hour). We retrospectively investigated the complications of NGT feeding in each group.

RESULTS

The incidence of diarrhea was clearly lower in the SSRAG than in the LG. Among patients with lower-gastrointestinal tract symptoms, stool form scale scores and maximum defecation frequency per day were significantly lower in the SSRAG than in the LG (P = .001 for both). Rapid administration of a semisolid diet via an NGT resulted in fewer complications and shorter feeding times for orthognathic surgery patients.

CONCLUSIONS

The rapid administration of a semisolid diet via an NGT should decrease the complications of NGT feeding and improve the quality of the perioperative period for patients. The findings of this study will help clinicians select NGT diets for relatively young, healthy patients, such as orthognathic surgery patients.

DGKζ ablation engenders upregulation of p53 level in the spleen upon whole-body ionizing radiation

The tumor suppressor gene product p53, which coordinates the cellular response to various stresses, is subject to tight regulation by a complex network of signal transduction. The DGK family metabolizes lipidic second messenger diacylglycerol to produce phosphatidic acid. Our earlier studies showed that one isozyme, DGKζ, is involved in the regulatory mechanism of p53. In a cellular model of doxorubicin-induced DNA damage, overexpression of wild-type DGKζ suppresses p53 protein induction and reduces apoptosis, whereas knockdown of DGKζ upregulates p53 protein level and promotes apoptosis. Further examination reveals that DGKζ facilitates p53 degradation via ubiquitin-proteasome system in the cytoplasm. However, it remains undetermined whether the regulatory mechanism of DGKζ on p53 function found in cell-based experiments is also functional at the animal level. This study was conducted to elucidate this point using an experiment with DGKζ-KO mice under DNA damage induced by whole-body ionizing radiation. Our results reveal that p53 protein is induced robustly in the spleen of DGKζ-KO mice upon exposure to ionizing radiation, thereby promoting apoptosis in this organ. Taken together, the results demonstrate that DGKζ plays a sentinel role in p53 expression at the cellular and organismal levels after DNA damaging stress conditions.

Three-Dimensional Printing Model as a Tool to Assist in Surgery for Large Mandibular Tumour: a Case Report

Objectives

Recently, three-dimensional printing models based on preoperative computed tomography and magnetic resonance imaging images have been widely used in medical fields. This study presents an effective use of the three-dimensional printing model in exploring complex spatial relationship between the tumour and surrounding tissue and in simulation surgery based planning of the operative procedure.

Material and Methods

The patient was a 7-year-old boy with ameloblastic fibro-odontoma. Prior to surgery, a hybrid three-dimensional printing model consisting of the jaw bone, the tumour and the inferior alveolar nerve was fabricated. After the simulation surgery based on this model, enucleation of the tumour, leaving tooth 46 intact (Universal Numbering System by ADA) safe, was planned.

Results

Enucleation of the tumour was successfully carried out. One year later, healing was found to be satisfactory both clinically and radiographically.

Conclusions

The study presented an effective application of a novel hybrid three-dimensional printing model composed of hard and soft tissues. Such innovations can bring significant benefits, especially to the field of oncological surgery.

Acute septic arthritis of the temporomandibular joint derived from otitis media: a report and review of the English and Japanese literature

Septic arthritis of the temporomandibular joint (SATMJ) is an extremely rare disease with characteristic features of preauricular pain, swelling, redness, and malocclusion. The present report describes a case of SATMJ derived from otitis media, which resulted in a good outcome. We also reviewed the English and Japanese literature with special interest in etiology. It is generally agreed that contiguous or distant infection and trauma are common etiological factors of SATMJ. So far, these etiological factors are mainly discussed based on hypotheses rather than sufficient evidence. Therefore, in many past cases, accurate causes were not identified. To our knowledge, our case is the third report of SATMJ following otitis media. In addition, this is the first case in which the pathogenic bacterium responsible for the otitis media was the definite cause of the SATMJ. Cases of SATMJ are sometimes misdiagnosed with otitis media, and SATMJ derived from otitis media is extremely rare. Dentists and otolaryngologists should collaborate for the management of this disease as needed.

Effect of timing of collection of salivary metabolomic biomarkers on oral cancer detection

The aim of this study is to evaluate the effect of duration after meals for saliva collections for oral cancer detection using metabolomics. Saliva samples were collected from oral cancer patients (n = 22) and controls (n = 44). Saliva from cancer patients was collected 12 h after dinner, and 1.5 and 3.5 h after breakfast. Control subjects fasted >1.5 h prior to saliva collection. Hydrophilic metabolites were analyzed using capillary electrophoresis mass spectrometry. Levels of 51 metabolites differed significantly in controls vs. oral cancer patients at the 12-h fasting time point (P < 0.05). Fifteen and ten metabolites differed significantly at the 1.5- and 3.5-h time points, respectively. The area of under receiver operating characteristic curve for discriminating oral cancer patients from controls was greatest at the 12-h fasting time point. The collection time after meals affects levels of salivary metabolites for oral cancer screening. The 12-h fasting after dinner time point is optimal. This study contributes to design of saliva collection protocols for metabolomics-based biomarker discovery.

Report of a case of acinic cell carcinoma of the upper lip and review of Japanese cases of acinic cell carcinoma of the minor salivary glands

Acinic cell carcinoma (ACC) is a malignant tumor of the salivary glands. The majority of ACCs occur in the parotid gland, and ACCs of the minor salivary glands (MSGs) are relatively infrequent. We describe here a patient with ACC of the upper lip. The patient was a 31-year-old male who presented with a nodular mass on the left upper lip. The preoperative diagnosis was benign tumor or cyst, and the lesion was surgically excised. The histological diagnosis was ACC. The postoperative course was uneventful. No recurrence or metastasis was detected at 13 months postoperatively. In addition, we retrospectively reviewed 21 reported Japanese patients with ACC of the MSGs. In 7 of the 21 patients, the preoperative diagnosis was benign tumor, and the tumors were resected without preoperative biopsy. Kaplan–Meier analysis showed that disease-free survival was worse in patients who underwent resection with a preoperative diagnosis of benign tumor than in patients who underwent resection with a preoperative diagnosis of malignant tumor. The rate of recurrence was higher for ACCs assumed to be benign lesions on a purely clinical basis, or without an accurate preoperative biopsy. ACCs of the MSGs are easy to be misdiagnosed for benign lesions such as mucous cysts or hemangiomas. Correct preoperative diagnosis and initial therapy may therefore be the most important prognostic factors.

Key words:Acinic cell carcinoma, Kaplan-Meier analysis, minor salivary glands, prognosis, upper lip.

Circulating miR-223 in Oral Cancer: Its Potential as a Novel Diagnostic Biomarker and Therapeutic Target

Circulating microRNAs (miRNAs) have been detected in various types of cancer and have been proposed as novel biomarkers for diagnosis and treatment. Until recently, however, no studies had comprehensively examined circulating miRNAs in oral cancer. The current study used an ultra-sensitive genome-wide miRNA array to investigate changes in circulating miRNAs in plasma from five patients with oral cancer and ten healthy individuals. Results indicated that there were only a few circulating miRNAs, including miR-223, miR-26a, miR-126, and miR-21, that were up-regulated in patients with oral cancer. A subsequent validation test indicated that circulating miR-223 levels were significantly higher (~2-fold, P< 0.05) in patients with oral cancer (n = 31) than in those without cancer (n = 31). Moreover, miR-223 was found to be up-regulated in tumor-adjacent normal tissue compared to tumor tissue from patients with oral cancer. A gain-of-function assay was performed to explore the potential roles of circulating miR-223 in the development of oral cancer. Results revealed that miR-223 functions as a tumor suppressor by inhibiting cell proliferation and inducing apoptosis. In conclusion, this study suggested that circulating miR-223 may serve as a potential biomarker for diagnosis and that it may represent a novel therapeutic target for treatment of oral cancer.

Nuclear Translocation of p65 is Controlled by Sec6 via the Degradation of IκBα

Nuclear factor-κB (NF-κB) is an inducible transcription factor that mediates immune and inflammatory responses. NF-κB pathways are also involved in cell adhesion, differentiation, proliferation, autophagy, senescence, and protection against apoptosis. The deregulation of NF-κB activity is found in a number of disease states, including cancer, arthritis, chronic inflammation, asthma, neurodegenerative diseases, and heart disease. The 90 kDa ribosomal S6 kinase (p90RSK) family, which is serine/threonine kinases, is phosphorylated by extracellular signal-regulated kinase1/2 (ERK1/2) and is related to NF-κB pathways. Our previous studies revealed that Sec6, a component of the exocyst complex, plays specific roles in cell-cell adhesion and cell cycle arrest. However, the mechanism by which Sec6 regulates the NF-κB signaling pathway is unknown. We demonstrated that Sec6 knockdown inhibited the degradation of IκBα and delayed the nucleus-cytoplasm translocation of p65 in HeLa cells transfected with Sec6 siRNAs after treatment with tumor necrosis factor alpha (TNF-α). Furthermore, the binding of p65 and cAMP response element binding protein (CREB) binding protein (CBP) or p300 decreased and NF-κB related genes which were inhibitors of NF-κB alpha (IκBα), A20, B cell lymphoma protein 2 (Bcl-2), and monocyte chemoattractant protein-1 (MCP-1) were low in cells transfected with Sec6 siRNAs in response to TNF-α stimulation. Sec6 knockdown decreased the expression of p90RSKs and the phosphorylation of ERK or p90RSK1 at Ser380 or IκBα at Ser32. The present study suggests that Sec6 regulates NF-κB transcriptional activity via the control of the phosphorylation of IκBα, p90RSK1, and ERK.

Downregulation of diacylglycerol kinase ζ enhances activation of cytokine-induced NF-κB signaling pathway

The transcription factor NF-κB family serves as a key component of many pathophysiological events such as innate and adaptive immune response, inflammation, apoptosis, and oncogenesis. Various cell signals trigger activation of the regulatory mechanisms of NF-κB, resulting in its nuclear translocation and transcriptional initiation. The diacylglycerol kinase (DGK) family, a lipid second messenger-metabolizing enzyme in phosphoinositide signaling, is shown to regulate widely various cellular processes. Results of recent studies suggest that one family member, DGKζ, is closely involved in immune and inflammatory responses. Nevertheless, little is known about the regulatory mechanism of DGKζ on NF-κB pathway in cytokine-induced inflammatory signaling. This study shows that siRNA-mediated DGKζ knockdown in HeLa cells facilitates degradation of IκB, followed by nuclear translocation of NF-κB p65 subunit. In addition, DGKζ-deficient MEFs show upregulation of p65 subunit phosphorylation at Serine 468 and 536 and its interaction with CBP transcriptional coactivator upon TNF-α stimulation. These modifications of p65 subunit might engender enhanced NF-κB transcriptional reporter assay of DGKζ knockdown cells. These findings provide further insight into the regulatory mechanisms of cytokine-induced NF-κB activation.