Effect of oral health status and oral function on malnutrition in community-dwelling older adult dental patients: A two-year prospective cohort study.

OBJECTIVES: To survey oral status in detail and clarify the factors associated with nutritional status as evaluated by the Mini Nutritional Assessment. BACKGROUND: Malnutrition is common in older adults and increases the risk of frailty, sarcopenia, and mortality. However, few longitudinal studies have been performed to investigate the causal effect of oral status on malnutrition in detail, and the information reported in those longitudinal studies has been limited to dentition status and swallowing ability. MATERIALS AND METHODS: The participants in this prospective cohort study were patients who visited the Preventive Dentistry Clinic at Okayama University Hospital from November 2017 to January 2021. The number of teeth, periodontal condition, oral function (oral diadochokinesis, masticatory ability, number of bacteria in tongue coating, occlusal force, oral moisture, tongue pressure, swallowing function), nutritional status, the number of comorbidities, and mental health status were examined. These variables were analysed using structural equation modelling (SEM). RESULTS: The final analysis included 141 participants (40 males and 101 females; mean age, 73.5 ± 6.3 years; follow-up rate: 79.7%). The results of the SEM revealed that oral status (number of teeth present and swallowing function) was positively associated with nutritional status 2 years later. In addition, age was negatively associated with oral status. CONCLUSION: In community-dwelling older adult dental patients (age ≥60 years), oral function at baseline was associated with nutritional status two years later.

Association between serum miRNAs and gingival gene expression in an obese rat model.

INTRODUCTION: Recent studies have reported a relationship between periodontitis and obesity; however, the mechanisms of obesity's effects on periodontitis are not well understood. On the other hand, microRNAs (miRNAs) are known to play key roles in the post-transcriptional regulation gene expression by suppressing translation and protein synthesis. We examined the association between obesity-related miRNAs and gene expression in gingival tissue using miRNA-messenger RNA (mRNA) pairing analysis in an obese rat model. METHODS: Sixteen male Wistar rats aged 8 weeks old were divided into two groups: the control group was fed a normal powdered food for 8 weeks, and the obesity group was fed a high-fat diet for 8 weeks. Distance from the cement-enamel junction to the alveolar bone crest of the first molars was measured. miRNA microarray analysis was performed on samples of serum and gingival tissue; the resulting data were used to calculate fold changes in miRNA levels in the obesity group relative to the control group, and miRNA-mRNA pairing analysis was performed to identify mRNAs potentially targeted by miRNAs of interest. RESULTS: Alveolar bone loss in the obesity group exceeded that in the control group (p = .017). miRNA-mRNA pairing analysis identified an association between 4 miRNAs (miR-759, miR-9a-3p, miR-203b-3p, and miR-878) that were differentially expressed in the obesity and control groups and 7 genes (Ly86, Arid5b, Rgs18, Mlana, P2ry13, Kif1b, and Myt1) expressed in gingival tissue. CONCLUSION: This study revealed that several miRNAs play an important role in the mechanism of periodontal disease progression induced by the obesity.

Oral function, nutritional status and physical status in Japanese independent older adults.

OBJECTIVES: To clarify the associations among oral status, nutritional status and physical status in Japanese independent older adults. BACKGROUND: It is important to focus on factors affecting physical status associated with life dysfunction, long-term care and mortality. However, there are very few reports of the associations among oral status, nutritional status and physical status. MATERIALS AND METHODS: Patients who visited the Preventive Dentistry Clinic at Okayama University Hospital from November 2017 to January 2019 participated in this cross-sectional study. Number of teeth, periodontal condition and oral function were recorded. Bacteria counts in tongue dorsum, oral wettability, tongue pressure, tongue and lip movement function [oral diadochokinesis (ODK)], masticatory ability, bite force and swallowing function were measured. Nutritional status was assessed by the Mini Nutritional Assessment. Physical frailty status and Elderly Status Assessment Set were also evaluated. These variables were analysed by structural equation modelling (SEM). RESULTS: Data from 203 patients were analysed (63 males and 140 females). Patients ranged in age from 60 to 93 years. The final model of the path diagram was completed by SEM. ODK was positively associated with nutritional status, and nutritional status was negatively associated with frailty. Age was associated with ODK, nutritional status and frailty. CONCLUSION: Based on the associations among age, ODK, nutritional status and frailty, maintaining tongue movement function may contribute to good nutritional status and physical status in Japanese independent older adults.

Parafunctional masseter muscle activity during waking is related to periodontitis progression: A pilot prospective cohort study.

AIM: The purpose of this pilot prospective cohort study was to investigate the effects of parafunctional masseter muscle activity on periodontitis progression among patients receiving supporting periodontal therapy (SPT). MATERIALS AND METHODS: We collected data of patients treated at Okayama University Hospital from August 2014 to September 2018. The progression group was defined as patients with ≥2 teeth demonstrating a longitudinal loss of proximal attachment of ≥3 mm during the 3-year study period and/or at least one tooth extraction due to periodontitis progression. Surface electromyography of masseter muscles at baseline was continuously recorded while patients were awake and asleep. RESULTS: We analysed 48 patients (36 females) aged 66.8 ± 9.1 years (mean ± SD). The rate of parafunctional masseter muscle activity during waking hours and sleeping hours at baseline was 60.4% and 52.1%, respectively. Cox's proportional hazards regression model showed that the incidence of periodontitis progression was significantly associated with number of teeth present (p = 0.001) and parafunctional masseter muscle activity during waking hours (p = 0.041). CONCLUSION: Our results suggest that parafunctional masseter muscle activity during waking hours is a risk factor for periodontitis progression among patients receiving SPT.

Oral diadochokinesis is related to decline in swallowing function among community-dwelling Japanese elderly: a cross-sectional study.

BACKGROUND: Since oral organs function in the first stage of the swallowing process, it is possible that decline in swallowing function can be partly related to oral frailty. AIMS: The purpose of this study was to investigate the association between swallowing function and oral function among community-dwelling elderly Japanese and to propose cut-off values for screening of decline in swallowing function. METHODS: A total of 188 participants were included in the analysis. The number of present teeth and functioning teeth were counted. Bacteria counts in tongue coat, oral wettability, tongue pressure, oral diadochokinesis (ODK), masticatory ability and bite force were examined. Swallowing function was assessed using the 10-item Eating Assessment Tool (EAT-10). Receiver operating characteristic curves were used to determine the cut-off points of each oral function parameter. A logistic regression model was performed to determine the combination of parameters with the highest accuracy for differentiating decline in swallowing function from normal. RESULTS: Subjects with ODK /pa/ sound < 6.2 times/second had higher prevalence of swallowing problems than those with 6.2 times/second or more. EAT-10 scores of one or more were significantly related to older age (≥ 71 years old; odds ratio [OR] 4.321) and reduced ODK /pa/ sound (< 6.2 times/second; OR 2.914). CONCLUSIONS: Among community-dwelling elderly Japanese, those who were suspected of having decline in swallowing function had lower oral function than those who did not, and the cut-off values were 71 years of age and ODK /pa/ sound 6.2 times/s.

Association between the incidence of early childhood caries and attending childcare among toddlers in a rural area of Japan: a prospective cohort study.

OBJECTIVE: The purpose of this study was to investigate the association between the incidence of early childhood caries (ECC) and factors of the daytime childcare environment among toddlers in a rural area of Japan. MATERIAL AND METHODS: This was a prospective cohort study. Data collected from 2011 to 2015 were obtained for initially caries-free, 18-month-old toddlers (N = 640). Dentists recorded the numbers of decayed, missing and filled teeth (caries incidence) of toddlers at baseline (age 18 months) and follow-up (age 3 years). In addition, a questionnaire survey was conducted on guardians at baseline to record data on lifestyle. RESULTS: In total, 159 (24.8%) toddlers had newly identified ECC at follow-up. Logistic regression analyses indicated that the incidence of ECC was significantly associated with receiving daytime care at a nursery school (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.05-2.30; p = .029), prolonged breastfeeding (OR, 1.71; 95%CI, 1.15-2.55; p = .008), and snacking ≥3 times a day (OR, 2.39; 95%CI, 1.53-3.74; p < .001). CONCLUSION: These findings suggest that receiving daytime care at a nursery school, prolonged breastfeeding, and frequent snacking are associated with an increased risk of ECC among Japanese toddlers in rural areas.

A Validation Study of the National Database of Health Insurance Claims and Specific Health Checkups of Japan Regarding the Annual Number of Tooth Extractions Performed Across the Entire Japanese Population.

This report describes a validation study of data in the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) obtained by nationwide surveys on tooth extractions. The following 3 data sources on tooth extractions in Japan were compared: (1) the Nationwide Survey of the Reasons for Permanent Tooth Extractions in Japan (a previous survey conducted by the present authors); (2) the Statistics on Medical Care Activities in Public Health Insurance; and (3) the 4th NDB Open Data Japan. Source 1 was a nationwide survey conducted in 2018; sources 2 and 3 comprised data that are freely available for use by the public. In Source 1, 2,345 of 5,250 dentists approached responded to the questionnaire (recovery rate: 44.8%). The number of extracted teeth among younger age groups (aged 25-50 years) reported in Source 1 was lower than that in the other two sources. In contrast, the number of extracted teeth among older age groups reported in Source 1 was higher than that reported in the other two sources. However, when stratified by age group, all differences across the 3 sources regarding the mean annual number of tooth extractions were <0.05 teeth/year. The present results suggest that the NDB is a reliable resource for data on tooth extractions performed across the entire Japanese population.

Association of dental occlusal support with the Prognostic Nutritional Index in patients with esophageal cancer who underwent esophagectomy.

BACKGROUND: The Prognostic Nutritional Index is useful for predicting surgical risk and overall survival based on preoperative immunological and nutritional status in patients undergoing digestive organ cancer surgery. The purpose of this study was to examine the association between the Prognostic Nutritional Index and dental status in patients with esophageal cancer who underwent esophagectomy. METHODS: This retrospective case-control study included 73 patients who underwent resection of esophageal cancer (69 males, 4 females; age 36-83). General and dental status were evaluated. The Prognostic Nutritional Index was calculated based on the serum albumin concentration and the total lymphocyte count, and subjects were divided into two groups based on index scores: a higher group, characterized by scores ≥ 45 (n = 54); and a lower group, characterized by scores < 45 (n = 19). Univariate analysis and multiple logistic regression analyses were used to compare between groups. RESULTS: Total protein, C-reactive protein, the number of sound and total decayed, missing and filled teeth, and the rate of patients with poor dental occlusal support showed significant differences between the lower and higher Prognostic Nutritional Index groups (p < 0.05). Stepwise logistic regression analysis by backward selection approach showed that low total protein, few sound teeth, and poor status of dental occlusal support were significantly associated with the lower Prognostic Nutritional Index (p = 0.007, 0.042, and 0.009, respectively). CONCLUSION: Dental status, especially dental occlusal support and the number of sound teeth, showed a positive relationship with the Prognostic Nutritional Index in esophageal cancer patients who underwent esophagectomy.

Association between intensive health guidance focusing on eating quickly and metabolic syndrome in Japanese middle-aged citizens.

PURPOSE: The purpose of this intervention study was to investigate whether intensive health guidance focusing on eating quickly can prevent metabolic syndrome (MetS) more effectively than standard routine guidance in Japanese citizens living in rural areas. METHODS: This controlled, non-randomized, intervention study analyzed 141 participants with MetS at baseline. Participants in the intervention group received health guidance focusing on eating quickly and standard health guidance about MetS in accordance with the guidelines of the Ministry of Health, Labour and Welfare in Japan, whereas participants in the control group received only standard health guidance about MetS. The primary study outcome was the prevalence of MetS at a 1-year follow-up. RESULTS: At 1-year follow-up, the prevalence of MetS in the intervention group was significantly lower than that in the control group (p = 0.003). The decreases in body weight, body mass index, waist circumference and triglycerides from baseline to 1 year were significantly greater in the intervention group than in the control group (p < 0.05). CONCLUSION: Intensive health guidance focusing on eating quickly is more effective for improving MetS than standard Japanese health guidance alone. LEVEL OF EVIDENCE: Level II, Evidence obtained from well-designed controlled trials without randomization. TRIAL REGISTRY NAME, REGISTRATION IDENTIFICATION NUMBER, AND URL FOR THE REGISTRY: UMIN, UMIN000030600, http://www.umin.ac.jp/ctr/index-j.htm.

Structural equation modeling to detect predictors of oral health-related quality of life among Japanese university students: a prospective cohort study.

PURPOSE: This prospective cohort study of Japanese university students aimed to identify factors that might affect oral health-related quality of life (OHRQoL) and longitudinal relationships over a period of 3 years. METHODS: Students (n = 487) provided complete data before entering and 3 years later (before university graduation) participated in the present study. Decayed, missing, and filled teeth (DMFT) scores, community periodontal index, ratios (%) of teeth with bleeding on probing, and malocclusion were determined during oral examinations. The questionnaire addressed age, sex, self-rated oral health, oral health behavior, subjective oral symptoms, and OHRQoL determined using the oral health impact profile (OHIP)-14. Associations were analyzed using structural equation modeling (SEM). RESULTS: The OHRQoL significantly worsened according to OHIP-14 total score (p = 0.001). The final model in the symptoms of SEM analysis showed that OHRQoL at follow-up positively correlated with OHRQoL at baseline. Self-rated oral health was directly associated with the OHRQoL at baseline (p < 0.05). CONCLUSIONS: This study determined that OHRQoL at baseline was a direct predictor, and that self-rated oral health were indirect predictors of OHRQoL at follow-up among Japanese university students.

Efficacy of Oral Care Provided by Interprofessional Collaboration for a Patient with Esophageal Cancer Associated with Post-polio Syndrome during Neoadjuvant Chemotherapy.

Preoperative oral care is helpful to prevent postoperative complications in patients who are undergoing esophagectomy. Here, we report the case of an 81-year-old Japanese man with an upper limb disability caused by post-polio syndrome who was receiving neoadjuvant chemotherapy for esophageal cancer. He had poor oral health status and developed oral complications as a side effect of chemotherapy. He could not brush his teeth by himself. However, infection control by oral care provided by an interprofessional collaboration successfully improved his oral hygiene, and his follow-up involved no severe complications. Interprofessional collaboration is useful especially for patients with upper limb disability.

Detection of Salivary miRNAs Reflecting Chronic Periodontitis: A Pilot Study.

The purpose of this cross-sectional pilot study was to find salivary microRNAs (miRNAs) reflecting periodontal condition in chronic periodontitis. One hundred and twenty chronic periodontitis patients (mean age, 68.4 years) participated in the study, from whom unstimulated whole saliva was collected. A multiphase study was conducted to explore salivary miRNAs as biomarkers of periodontitis. At first, a polymerase chain reaction (PCR) array was performed to compare salivary miRNAs profiles in no and mild (no/mild) and severe periodontitis patients. Next, the relative expression of salivary miRNAs on individual samples was assessed by real-time reverse transcription-PCR. The numbers (%) of patients were 26 (21.6%, no/mild), 58 (48.3%, moderate) and 36 (30.0%, severe), respectively. Among 84 miRNAs, only the relative expression of hsa-miR-381-3p in the severe periodontitis group was significantly higher than that of the no/mild periodontitis group (p < 0.05). Among the 120 patients, there was also a significant correlation between the relative expression of hsa-miR-381-3p and the mean probing pocket depth (PPD) (r = 0.181, p < 0.05). Salivary hsa-miR-381-3p was correlated with periodontitis condition in chronic periodontitis patients.

Change in tongue pressure and the related factors after esophagectomy: a short-term, longitudinal study.

BACKGROUND: Dysphagia is a prominent symptom after esophagectomy and may cause aspiration pneumonia. Swallowing evaluation after esophagectomy can predict and help control the incidence of postoperative pneumonia. The aim of this study was to clarify whether the change in tongue pressure was associated with any related factor and postoperative dysphagia/pneumonia in patients with esophageal cancer after esophagectomy. METHODS: Fifty-nine inpatients (41 males and 18 females; 33-77 years old) who underwent esophagectomy participated in this study. Measurement of tongue pressure and the repetitive saliva swallowing test (RSST) was performed before esophagectomy (baseline) and at 2 weeks postoperatively. The general data were collected from patients' medical records, including sex, age, type of cancer, cancer stage, location of cancer, operative approach, history of previous chemotherapy, surgical duration, amount of bleeding during surgery, incidences of postoperative complications, intubation period, period between surgery and initiation of oral alimentation, and intensive care unit (ICU) stay, blood chemical analysis, and lifestyle. RESULTS: Tongue pressure decreased significantly after esophagectomy (p = 0.011). The decrease of tongue pressure was significantly associated with length of ICU stay and preoperative tongue pressure on multiple regression analysis (p < 0.05). The decrease of tongue pressure in the RSST < 3 or postoperative pneumonia (+) group was significantly greater than in the RSST ≥ 3 (p = 0.003) or pneumonia (-) group (p = 0.021). CONCLUSIONS: The decrease in tongue pressure was significantly associated with the length of ICU stay, preoperative tongue pressure, and the incidence of dysphagia and pneumonia among inpatient after esophagectomy.

Commensal Microbiota Enhance Both Osteoclast and Osteoblast Activities.

Recent studies suggest that the commensal microbiota affects not only host energy metabolism and development of immunity but also bone remodeling by positive regulation of osteoclast activity. However, the mechanism of regulation of bone cells by the commensal microbiota has not been elucidated. In this study, 8-week-old specific pathogen-free (SPF) and germ-free (GF) mice were compared in terms of alveolar bones and primary osteoblasts isolated from calvarias. Micro-CT analysis showed that SPF mice had larger body size associated with lower bone mineral density and bone volume fraction in alveolar bones compared with GF mice. Greater numbers of osteoclasts in alveolar bone and higher serum levels of tartrate-resistant acid phosphatase 5b were observed in SPF mice. Tissue extracts from SPF alveolar bone showed higher levels of cathepsin K, indicating higher osteoclast activity. SPF alveolar extracts also showed elevated levels of γ-carboxylated glutamic acid⁻osteocalcin as a marker of mature osteoblasts compared with GF mice. Polymerase chain reaction (PCR) array analysis of RNA directly isolated from alveolar bone showed that in SPF mice, expression of mRNA of osteocalcin, which also acts as an inhibitor of bone mineralization, was strongly enhanced compared with GF mice. Cultured calvarial osteoblasts from SPF mice showed reduced mineralization but significantly enhanced expression of mRNAs of osteocalcin, alkaline phosphatase, insulin-like growth factor-I/II, and decreased ratio of osteoprotegerin/receptor activator of nuclear factor-kappa B ligand compared with GF mice. Furthermore, PCR array analyses of transcription factors in cultured calvarial osteoblasts showed strongly upregulated expression of Forkhead box g1. In contrast, Gata-binding protein 3 was strongly downregulated in SPF osteoblasts. These results suggest that the commensal microbiota prevents excessive mineralization possibly by stimulating osteocalcin expression in osteoblasts, and enhances both osteoblast and osteoclast activity by regulating specific transcription factors.

Expression of Salivary miR-203a-3p Was Related with Oral Health-Related Quality of Life in Healthy Volunteers.

Oral health-related quality of life (OHRQoL) is a multidimensional construct that involves subjective evaluation of an individual's oral health. Although it is difficult to evaluate OHRQoL biologically, recently, it has been reported that circulating microRNAs (miRNAs) in several body fluids could reflect various health conditions. The aim of this pilot study was to investigate whether salivary miRNAs expression differs according to OHRQoL in healthy volunteers. Forty-six volunteers (median age, 23.0 years) were recruited, and their OHRQoL was assessed using the Japanese version of the Oral Health Impact Profile (OHIP-J). Then, we compared salivary microRNA profiles of the high-OHRQoL group (≤25th percentile score of OHIP-J) and the low-OHRQoL group (≥75th percentile score of OHIP-J) using the polymerase chain reaction (PCR) array and the quantitative real-time PCR. There were no significant differences between the two groups in terms of oral health status. In the PCR array, miR-203a-3p and miR-30b-5p were significantly more expressed in the low-OHRQoL group (p < 0.05). Quantitative real-time PCR assay also showed that miR-203a-3p was more highly expressed in the low-OHRQoL group than in the high-OHRQoL group (p < 0.05). These observations suggest that expression of salivary miR-203a-3p was related with OHRQoL in healthy volunteers.

School-Based Fluoride Mouth-Rinse Program Dissemination Associated With Decreasing Dental Caries Inequalities Between Japanese Prefectures: An Ecological Study.

BACKGROUND: Dental caries inequalities still severely burden individuals' and society's health, even in countries where fluoride toothpastes are widely used and the incidence of dental caries has been decreasing. School-based fluoride mouth-rinse (S-FMR) programs, a population strategy for dental caries prevention, might decrease dental caries inequalities. This study investigated the association between S-FMR and decreasing dental caries prevalence and caries-related inequalities in 12-year-olds by Japanese prefecture. METHODS: We conducted an ecological study using multi-year prefecture-level aggregated data of children born between 1994 and 2000 in all 47 Japanese prefectures. Using two-level linear regression analyses (birth year nested within prefecture), the association between S-FMR utilization in each prefecture and 12-year-olds' decayed, missing, or filled permanent teeth (DMFT), which indicates dental caries experience in their permanent teeth, were examined. Variables that could explain DMFT inequalities between prefectures, such as dental caries experience at age 3 years, dentist density, and prefectural socioeconomic circumstances, were also considered. RESULTS: High S-FMR utilization was significantly associated with low DMFT at age 12 (coefficient -0.011; 95% confidence interval, -0.018 to -0.005). S-FMR utilization explained 25.2% of the DMFT variance between prefectures after considering other variables. Interaction between S-FMR and dental caries experience at age 3 years showed that S-FMR was significantly more effective in prefectures where the 3-year-olds had high levels of dental caries experience. CONCLUSIONS: S-FMR, administered to children of all socioeconomic statuses, was associated with lower DMFT. Utilization of S-FMR reduced dental caries inequalities via proportionate universalism.

MicroRNAs as serum biomarkers for periodontitis.

AIM: Studies demonstrated that periodontitis modulates microRNA (miRNAs) expression rates in periodontal tissue. However, the relationship between periodontitis and miRNAs profile in circulation remains unclear. In this study, we investigated the effects of periodontitis on serum miRNAs profile in a rat model. MATERIAL AND METHODS: Male Wistar rats (n = 32, 8 weeks old) were divided into four groups of eight rats each. The control groups received no treatment for 2 or 4 weeks. In the other two groups, periodontitis was ligature induced for 2 or 4 weeks. Serum miRNAs expression profiles of each group were compared. RESULTS: Ligation around teeth induced periodontal inflammation at 2 weeks and periodontal tissue destruction at 4 weeks. Microarray results showed that 25 miRNAs were expressed with a <0.5 or >2 difference between the control and periodontitis groups at 4 weeks. Results of real-time PCR revealed that the periodontitis group up-regulated expression rates of serum miR-207 and miR-495 at 2 weeks, and miR-376b-3p at 4 weeks (p < 0.05). CONCLUSION: Serum miRNAs (miR-207, miR-495, and miR-376b-3p) could be valuable biomarkers for periodontitis.

Visualization of Oxidative Stress Induced by Experimental Periodontitis in Keap1-Dependent Oxidative Stress Detector-Luciferase Mice.

The aim of this study was to investigate whether a Keap1-dependent oxidative stress detector-luciferase (OKD-LUC) mouse model would be useful for the visualization of oxidative stress induced by experimental periodontitis. A ligature was placed around the mandibular first molars for seven days to induce periodontitis. Luciferase activity was measured with an intraperitoneal injection of d-luciferin on days 0, 1, and 7. The luciferase activity in the periodontitis group was significantly greater than that in the control group at seven days. The expressions of heme oxygenase-1 (HO-1) and malondialdehyde in periodontal tissue were significantly higher in the periodontitis group than in the control group. Immunofluorescent analysis confirmed that the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) occurred more frequently in the periodontitis group than in the control group. This study found that under oxidative stress induced by experimental periodontitis, the Nrf2/antioxidant defense pathway was activated and could be visualized from the luciferase activity in the OKD-LUC model. Thus, the OKD-LUC mouse model may be useful for exploring the mechanism underlying the relationship between the Nrf2/antioxidant defense pathway and periodontitis by enabling the visualization of oxidative stress over time.

Associations among oral health-related quality of life, subjective symptoms, clinical status, and self-rated oral health in Japanese university students: a cross-sectional study.

BACKGROUND: The present study aimed to elucidate the associations among self-rated oral health, clinical oral health status, oral health behaviors, subjective oral symptoms, and oral health-related quality of life (OHRQoL) in a group of Japanese university students. METHODS: Of 2051 participants, 2027 (98.83%) students received an optional oral examination and answered a questionnaire including items regarding age, sex, self-rated oral health, oral health behaviors, subjective oral symptoms, and OHRQoL [The Oral Health Impact Profile (OHIP)-14]. On oral examination, the decayed, missing, and filled teeth (DMFT) score, Community Periodontal Index (CPI), the percentage of teeth showing bleeding on probing (%BOP), and malocclusion were recorded. Structural equation modelling (SEM) analysis was used to test associations. RESULTS: The mean score (± SD) of OHIP-14 was 1.92 ± 5.47. In the SEM analysis, the final model showed that self-rated oral health, oral pain, malocclusion, and the DMFT score were directly associated with the OHRQoL, and subjective symptoms of temporomandibular disorders (TMD) and recurrent aphthous stomatitis were both directly and indirectly associated (p < 0.05). CPI, %BOP, and oral health behaviors were excluded from the final model. CONCLUSIONS: OHRQoL was associated with self-related oral health, subjective symptoms of TMD, oral pain and stomatitis, DMFT, and malocclusion in this group of Japanese university students.