Sleep duration and severe periodontitis in middle-aged Japanese workers.

AIM: To evaluate the association between sleep duration and severe periodontitis in Japanese workers. MATERIALS AND METHODS: This cross-sectional study included 1130 workers (mean age 43.0 years) who underwent full-mouth periodontal examinations and health check-ups and completed a self-administered questionnaire that included questions on sleep duration. Logistic regression and a restricted cubic spline model were used to analyse the data. RESULTS: Severe periodontitis was identified in 6.3% of the study population. Those with <5, 5-5.9, 6-6.9, 7-7.9, and ≥8 hr of sleep were 6.7%, 17.4%, 40.3%, 26.3%, and 8.9%, respectively. After adjusting for potential confounders, study participants who slept <5 hr were more likely to have severe periodontitis (adjusted odds ratio = 2.64; 95% confidence interval = 1.06-6.60) than those who slept 7-7.9 hr. The spline model, with a reference value of 399 min (the median sleep duration), showed a non-linear association between sleep duration and severe periodontitis, where an increased prevalence of severe periodontitis was observed only among those with a shorter sleep duration. The prevalence of severe periodontitis did not increase with longer sleep duration. CONCLUSIONS: Short sleep duration was associated with severe periodontitis in this cohort of Japanese adults.

Interruption of regular dental visits during the COVID-19 pandemic due to concerns regarding dental visits was associated with periodontitis in Japanese office workers.

OBJECTIVE: To investigate the interrelationships among concerns regarding dental visits, the status of regular dental visits, and periodontal health during the coronavirus disease 2019 (COVID-19) pandemic. BACKGROUND: Continuous oral health care and regular dental visits are important for maintaining periodontal health. Due to the possibility of contracting COVID-19, individuals have been reluctant to visit medical institutions. It is unclear how the periodontal health of the Japanese population has been affected by the interruption of regular dental visits during the COVID-19 pandemic and how concerns regarding dental visits have affected attendance at regular dental visits. METHODS: This study included 199 Japanese office workers in one municipal office at Fukuoka Prefecture, Japan (average age = 42.6 years; age range = 19-77 years; 123 men and 76 women). Periodontitis was defined based on a full-mouth periodontal examination. The status of regular dental visits during the COVID-19 pandemic and concerns regarding dental visits were obtained via questionnaire. We tested the hypothesis that concerns regarding dental visits would indirectly affect periodontal health through the interruption of regular dental visits during the COVID-19 pandemic. We used mediation analysis, in which concerns regarding dental visits (present or absent) were set as the exposure, periodontitis (present or absent) was set as the outcome, and the status of regular dental visits (continued during the COVID-19 pandemic or not) was set as the mediator. RESULTS: Of the 199 study participants, 108 had a habit of attending regular dental visits. Of these, 31 (28.7%) discontinued regular dental visits during the COVID-19 pandemic. Compared to the individuals who continued regular dental visits, those who discontinued regular dental visits had a higher prevalence of periodontitis (49.4% vs 77.4%, p < 0.05) and concerns regarding dental visits (22.1% vs 64.5%, p < 0.05). Discontinuing regular dental visits significantly mediated the association between concerns regarding dental visits and periodontitis (natural indirect effect: odds ratio = 1.68, 95% confidence interval = 1.02-2.79, proportion mediated = 64.3%). CONCLUSION: The study results showed that individuals who discontinued regular dental visits during the COVID-19 pandemic due to concerns regarding dental visits had relatively poor periodontal health.

A deep transfer learning approach for the detection and diagnosis of maxillary sinusitis on panoramic radiographs.

To investigate the use of transfer learning when applying a deep learning source model from one institution (institution A) to another institution (institution B) for creating effective models (target models) for the detection of maxillary sinuses and diagnosis of maxillary sinusitis on panoramic radiographs. In addition, to determine appropriate numbers of training data for the transfer learning. Source model was created using 350 panoramic radiographs from institution A as training data. Transfer learning was performed by adding 25, 50, 100, 150, or 225 panoramic radiographs as training data from institution B to the source model; this yielded the target models T25, T50, T100, T150 and T225. Each model was then evaluated using test data that comprised 40 images from institution A, 30 images from institution B. The performance indices (recall, precision and F1 score) for detecting the maxillary sinuses by the source model exceeded 0.98 when using test data A from institution A, but they deteriorated when using test data B from institution B. In the evaluation of target models using test data B, model T25 showed improved detection performance (recall of 0.967). The diagnostic performance of model T50 for maxillary sinusitis exceeded 0.9 in sensitivity. Transfer learning, which involves applying a small amount of data to the source model, yielded high performances in detecting the maxillary sinuses and diagnosing the maxillary sinusitis on panoramic radiographs. This study serves as a reference when adapting source models to other institutions.

Quantitative measurements of the articular areas of mandibular condyles with temporomandibular joint disorders using magnetic resonance imaging.

OBJECTIVE: The authors sought to clarify the variation in the condylar anterior functional surface (AFS) of patients with temporomandibular joint (TMJ) disorders using quantitative measurements by magnetic resonance imaging (MRI). METHODS: MR images of 68 joints (2 males, 32 females) were used. The subjects were classified into three groups: with/without defects of cortical bone groups and a combination group without defects. The AFS was measured as the length between the protrusive point and the apex of the condyle on MRI (4-mm-thick slices), and the quad value of the length was defined as the area on the slice. The summed quad values of all slices were used as the AFS area. Differences in the areas among the three groups were compared by one-way analysis of variance (ANOVA). RESULTS: The non-defect group had significantly larger AFS areas than the defect group. CONCLUSIONS: Quantitative measurement on MR images clarified the changes in the condylar sagittal appearance.

Palatal mucosal measurements in a Japanese population using cone-beam computed tomography.

STATEMENT OF THE PROBLEM: Although assessment of entire palatal mucosal thickness is important in many dental procedures, available data are mostly limited to the lateral aspect of the palate. PURPOSE OF THE STUDY: The objective of this study was to use cone-beam computed tomography (CBCT) to perform a comprehensive analysis of the palatal mucosal thickness from the gingival margin to the mid-palatine suture in a Japanese population. Associations of palatal mucosal thickness with the palatal vault depth were also examined. METHODS/MATERIALS: Measurements on the coronal plane were obtained from 44 adults with 3-mm interval in the canine (Ca), first premolar (P1), second premolar (P2), midpoint between first and second molars (M1d), first molar (M1), and second molar (M2). Furthermore, the location of greater palatine foramen (GPF) and palatine groove (PG) were also investigated. RESULTS: Canine region did not show a significant difference throughout measured points. P1, P2, and all molar regions were thickest at 9, 12, and 12 mm from the gingival margin, respectively. At 3 and 6 mm, Ca, P1, and P2 showed significantly greater thickness than the molar region. At 9 mm, P1 demonstrated a greater thickness than M1d, and P2 was greater than M1 and Mi. At 12 and 15 mm, P1 was thinner than P2, M1, and M2, whereas P2 was thinner than M2. M1 was thinner than M2. The high-vault group showed a significantly greater thickness than the low-vault group. In majority of subjects, GPF and PG were identified in second molar and first premolar to first molar, respectively. CONCLUSION: Palatal mucosa in a Japanese population was the thickest in canine to premolar regions at 9 to 12 mm from the gingival margin. Identification of GPF and PG using CBCT can assist diagnosis of palate seems to minimize surgical complications. CLINICAL SIGNIFICANCE: This study evaluated the thickness of palatal mucosa in a Japanese population using cone-beam computed tomography, covering a wide range. Canine to second premolar regions are the most suitable in harvesting palatal mucosa for the purpose of soft tissue grafts.

Mandibular lingual canals distribute to the dental crypts in prenatal stage.

PURPOSE: To describe configurations of human prenatal mandibular, lingual canals using a limited-field cone beam computed tomography (CBCT) to examine their origin and anatomical significance. MATERIALS AND METHODS: Nine fetal mandibles were examined using a CBCT. Mandibular maturity was assessed according to the mandibular size measured directly and image findings on development of dental crypts. Mandibular, lingual canals and the related foramina (mandibular, mental, and lingual foramina) were observed on axial, sagittal, and cross-sectional images. The horizontal position of mental and lingual foramina was assessed by direct observation using a loupe. RESULTS: In all nine mandibles, CBCT images depicted three separate mandibular canals, which individually occurred at the ramus area. One was a short canal directly connecting to the permanent molar crypt. The other two showed a parallel course, following the mandibular corpus toward the frontal area; the upper one connected to the mental foramen, and the lower one distributed anterior area of canine and incisor crypts. Lingual foramina were observed bilaterally in eight of nine mandibles, whose horizontal position was lingual against the crypt of deciduous canine. The lingual canals occurred from lingual foramina, and connected to the close deciduous tooth crypt or the mandibular canal distributing in the frontal area. CONCLUSIONS: It was suggested human dentition could be developed by plural mandibular and lingual canals.

Clinical and magnetic resonance imaging findings in patients with and without improvement after mandibular manipulation and conservative physical therapy for temporomandibular joint disorders.

OBJECTIVE: This study compared clinical and magnetic resonance imaging (MRI) findings in patients with anterior disk displacement without reduction (ADDWOR) who improved to anterior disk displacement with reduction (ADDWR) vs. patients who did not improve after mandibular manipulation (MM) and conservative self-administered physical therapy (CSAPT). STUDY DESIGN: Of 15 patients diagnosed with ADDWOR by MRI, 7 improved to ADDWR (WOR-WR) and 8 did not improve (WOR-WOR). The clinical and MRI findings before and after therapy were compared in each group. RESULTS: Significant differences between the groups included age, period of awareness of trismus, and maximum mouth opening (MMO). The MRI findings revealed significant differences in the degree of ADD and morphology of the disk and condyle. MMO significantly improved in the WOR-WR group between initial and follow-up visits. CONCLUSION: Patients who were successfully treated with MM and CSAPT tended to be <30 years old, with a longer period of awareness of trismus, MMO <40 mm, a slight or moderate degree of ADD, no deformity of the disk, and no morphologic change in the condyle. Patients with ADDWOR who are treated with MM and CSAPT require an accurate clinical examination and MRI before treatment.

The Association between Tannerella forsythia and the Onset of Fever in Older Nursing Home Residents: A Prospective Cohort Study.

Background: Periodontal pathogens are related to the incidence of systemic diseases. This study aimed to examine whether periodontal pathogen burden is associated with the risk of fever onset in older adults. Methods: Older adults in nursing homes, aged ≥65 years, were enrolled. The study was set in Kitakyushu, Japan. The body temperatures of participants were ≥37.2 °C and were recorded for eight months. As periodontal pathogens, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia were qualified by a real-time polymerase chain reaction at the baseline. For statistical analysis, the number of bacterial counts was logarithmically conversed to 10 as a base. Results: Data from 56 participants with a median age of 88 (62−98) years were available for analysis. The logarithmic-conversed bacterial counts of T. forsythia, but not P. gingivalis or T. denticola, were associated with the onset of fever in older residents. The Kaplan−Meier method revealed that the group with <104 of T. forsythia had significantly less cumulative fever incidence than the group with ≥104 of T. forsythia. The group with ≥104 of T. forsythia was associated with an increased risk of fever onset (hazard ratio, 3.7; 98% confidence interval, 1.3−10.2; p = 0.012), which was adjusted for possible confounders. Conclusions: Bacterial burden of T. forsythia in the oral cavity was associated with the risk of the onset of fever in older nursing homes residents.

The Ability of a Novel Trypsin-like Peptidase Activity Assay Kit to Detect Red-Complex Species.

The trypsin-like peptidase activity assay kit measures the trypsin-like protease produced by three red-complex species, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola, causing periodontitis, and detects the presence of these bacteria in samples. The purpose of this study was to investigate the relationship between the detection of TLPs by a novel TLP-AA, ADCHECK and the detection of red-complex pathogens by real-time PCR using tongue swabs from patients with periodontitis. The detection limit of trypsin-like protease activity by ADCHECK was validated using the culture supernatants of two different Porphyromonas gingivalis bacterial strains. Real-time PCR was performed to determine the number of red-complex species in the tongue coatings of patients with periodontal disease. Trypsin-like protease activity in tongue-swab samples was scored using ADCHECK. ADCHECK successfully detected trypsin-like protease activity in 103 Porphyromonas gingivalis bacterial strains. The specificity, positive predictive value, negative predictive value, and accuracy of ADCHECK for the presence of red-complex pathogens determined by real-time PCR were 90%, 97%, 98%, and 92%, respectively. ADCHECK is an effective tool for the detection of red-complex pathogens.

Differential diagnosis between calcifying odontogenic cyst and adenomatoid odontogenic tumor by computed tomography images.

OBJECTIVES: Calcifying odontogenic cysts (COC) and adenomatoid odontogenic tumors (AOT) have similar radiographic findings. We examined the radiographic and computed tomography (CT) images of patients histologically diagnosed with COC or AOT and identified their characteristic findings. METHODS: The subjects included 12 patients histologically diagnosed with COC or AOT (one female and five males per group), who underwent CT at our hospital between Nov 1998 and Jun 2019. The location of the lesion, impacted tooth, bone expansion, root resorption, tooth migration, calcified body, and presence or absence of a high-intensity zone in the marginal area of the lesion were examined. RESULTS: In patients with COC, five patients with COC exhibited bone expansion toward the buccal side. The lesion encompassing the crown was attached to the cement-enamel junction and contained a radiopaque lesion with a calcified body. In 6 patients with COC, irregularly shaped calcified bodies were observed with small tooth-like structures. In patients with AOT, all six patients with AOT exhibited bone expansion toward the buccal and lingual sides. The lesion encompasses a part of the tooth root or the entire tooth. Punctate calcification was observed within the lesion and the marginal area in three patients, and a high-intensity zone was observed in the marginal area of the lesion in two patients. CONCLUSION: We report imaging findings that may be characteristic of COC and AOT, suggesting that CT findings may be useful for differentiating between COC and AOT.

Automatic segmentation of the temporomandibular joint disc on magnetic resonance images using a deep learning technique.

OBJECTIVES: The aims of the present study were to construct a deep learning model for automatic segmentation of the temporomandibular joint (TMJ) disc on magnetic resonance (MR) images, and to evaluate the performances using the internal and external test data. METHODS: In total, 1200 MR images of closed and open mouth positions in patients with temporomandibular disorder (TMD) were collected from two hospitals (Hospitals A and B). The training and validation data comprised 1000 images from Hospital A, which were used to create a segmentation model. The performance was evaluated using 200 images from Hospital A (internal validity test) and 200 images from Hospital B (external validity test). RESULTS: Although the analysis of performance determined with data from Hospital B showed low recall (sensitivity), compared with the performance determined with data from Hospital A, both performances were above 80%. Precision (positive predictive value) was lower when test data from Hospital A were used for the position of anterior disc displacement. According to the intra-articular TMD classification, the proportions of accurately assigned TMJs were higher when using images from Hospital A than when using images from Hospital B. CONCLUSION: The segmentation deep learning model created in this study may be useful for identifying disc positions on MR images.

Detection of buccal perimandibular neurovascularisation associated with accessory foramina using limited cone-beam computed tomography and gross anatomy.

PURPOSE: To investigate buccal perimandibular neurovascularisation associated with the mandibular accessory buccal foramina (ABF) which were detected using a limited cone-beam computed tomography (limited CBCT). METHODS: Five Japanese cadaveric mandibles had been examined using helical CT to investigate the presence or absence of ABF. Two mandibles indicating the presence of AMF were examined more minutely using a limited CBCT. Following the three-dimensional radiological observation of ABF, the mandibles were removed from the cadavers and dissected with referring to the findings of AMF on the limited CBCT images. RESULTS: Four ABF of the three mandibular sides, which were depicted with limited CBCT, had different perimandibular neurovascularisation. Three accessory foramina were associated with the following arteries: a branch of the submental, facial, and buccal artery, and one was associated with a branch of the mental nerve. A branch of the mental nerve re-entered the mandible through the accessory foramen after it exited from a mental foramen. CONCLUSION: Limited CBCT is useful for pre-operative three-dimensional assessment of mandible since high-resolution analysis demonstrates not only the skeletal conditions but also the assessment and suggestions of perimandibular neurovascularisation.

Evaluation of the ability of the trypsin-like peptidase activity assay to detect severe periodontitis.

OBJECTIVES: N-benzoyl-DL-arginine peptidase (trypsin-like peptidase) is specifically produced by certain strains of periodontitis-associated bacteria. We aimed to examine the effectiveness of an objectively quantified trypsin-like peptidase activity assay (TLP-AA) for detecting severe periodontitis. METHODS: The study population included 347 adults (108 men and 239 women; average age, 43.3 years) who underwent a full-mouth periodontal examination. Specimens for the TLP-AA were obtained using tongue swabs. Using a color reader, the TLP-AA results were obtained as a* values, with higher positive a* values indicating an increased intense enzymatic activity. The predictive validity of the TLP-AA results for severe periodontitis was assessed using receiver operating characteristic curve analysis and the periodontitis case definition provided by the Centers for Disease Control and Prevention/American Academy of Periodontology as the gold standard. Furthermore, multivariable logistic regression analyses were performed to predict severe periodontitis using the TLP-AA results and health characteristics, as the exposure variables. RESULTS: Severe periodontitis was observed in 5.2% of the participants. TLP-AA had high diagnostic accuracy for severe periodontitis, with an area under the curve of 0.83 (95% confidence interval [CI]: 0.75-0.92). The cut-off score for the a* value that best differentiated individuals with severe periodontitis was 0.09, with a sensitivity of 83% and specificity of 77%. Multivariable logistic regression analyses revealed that the TLP-AA results were significantly associated with severe periodontitis after adjusting for health characteristics (adjusted odds ratios: 1.90 [95% CI: 1.37-2.62] for the a* value). CONCLUSIONS: Objectively quantified TLP-AA results are potentially useful for detecting severe periodontitis in epidemiological surveillance.

Validation of a self-report questionnaire for periodontitis in a Japanese population.

We aimed to assess the validity of the self-report questionnaire for periodontitis in a Japanese population. A Japanese 9-item self-report questionnaire, developed by translating English-version questions that were used to detect periodontitis, was validated against full-mouth clinically-assessed periodontitis in 949 Japanese adults (average age = 43.2 years). Multivariable logistic regression modeling was used to calculate the area under the receiver operating characteristic curve (AUC), wherein the periodontitis case definition of the Centers for Disease Control and Prevention/American Academy of Periodontology was considered the gold standard. Severe, moderate, and mild periodontitis were identified in 6.2%, 30.0%, and 6.7% of the study population, respectively. Self-reported oral health questions combined with socio-demographic and health-related variables had an AUC > 0.70 (range, 0.71-0.87) for any periodontitis category. Four oral health questions ("have gum disease," "loose tooth," "lost bone," and "bleeding gums") were selected in the parsimonious model for severe periodontitis. The periodontitis screening score generated by the responses to these four questions had an AUC, sensitivity, and specificity of 0.82, 73.1%, and 74.3%, respectively, where the cut-off was set at 2 points. In conclusion, a locally adapted version of the self-report questionnaire had an acceptable diagnostic capacity for the detection of periodontitis in this study population.

Effect of exposure parameters and gutta-percha cone size on fracture-like artifacts in endodontically treated teeth on cone-beam computed tomography images.

OBJECTIVES: To ascertain the effects of exposure parameters (tube current and tube voltage) and the gutta-percha cone (GPC) size on root fracture-like artifacts obtained with cone-beam computed tomography (CBCT). METHODS: Fracture-like artifacts appearing on CBCT images of nine extracted human mandibular premolars filled with GPCs of size #50 or #80 were analyzed using six exposure factors: two tube voltages (80 kV and 110 kV); and three tube currents (4 mA, 7 mA, and 10 mA). On axial images, the gray value (GV) was recorded at three points: the mesiobuccal portion (MBP) as the sound dentin, the mesial portion (MP) as the artifact line, and the water area (WA). The rate of decrease in the GV (RDGV) of the artifact line was calculated using the formula: RDGV (%) = (GV of MBP - GV of MP) × 100/(GV of MBP - GV of WA). RESULTS: Comparison of the #80 group and the #50 group with equal tube voltages and tube currents shows that artifact lines in the #80 group were more obvious than those in the #50 group. The artifact lines with 80 kV were markedly more visible than those with 110 kV for each tube current and GPC size. Tube current changes did not affect the artifact line for any tube voltage or GPC size. CONCLUSIONS: For the reduction of artifacts, we recommend selection of higher tube voltages and lower tube currents when taking CBCT images of teeth with each GPC size.

Anatomical characteristics of the mandibular lingual foramina observed on limited cone-beam CT images.

OBJECTIVES: The study aimed to investigate the regional frequency and anatomical properties of mandibular lingual foramina. MATERIAL AND METHODS: The regional frequency of the lingual foramina was investigated using limited cone-beam computed tomographic images of mandibles obtained from 190 examinations of 181 patients. The mesio-distal position of the lingual foramina was classified into 17 areas of the midline area and each tooth area. The vertical position was assessed from the positional relationship between the lingual foramina and mandibular canals. Additionally, anastomoses of the lingual canals from the lingual foramina to mandibular canals were observed on the images. RESULTS: One hundred and fifty-four lingual foramina were observed. The highest regional frequency was recognized in the midline area followed by second premolar and canine area. Plural lingual foramina were observed only in the midline areas. No lingual foramina were observed in the superior area of the mandibular canals. Thirty-one lingual foramina showed anastomoses between the lingual canals and mandibular canals. CONCLUSION: Information on the high regional frequency of lingual foramina in the second premolar area would be clinically significant to avoid life-threatening incidents because of the possible presence of an artery. It is therefore important to confirm the location of lingual foramina.

A case of venous malformation of the mandible.

OBJECTIVE: Vascular malformations occur more rarely in bones than in soft tissue, with 0.5-1.0% of all intraosseous tumors occurring in the mandible. We report a diagnostically challenging case of unilocular venous malformation of the mandible. CASE REPORT: A 76-year-old man presented with a heterogeneous, unilocular, radiolucent lesion with a well-defined border. Panoramic radiography and computed tomography imaging revealed a continuous white line on the cortical bone at the inferior border of the left mandibular molar region. A spherical lesion with a well-defined border and a clear round region in the left mandible were revealed on magnetic resonance imaging. The lesion had the same signal intensity as muscles on T1-weighted imaging, a homogeneous high-intensity signal on short T1-inversion recovery imaging, and a well-defined low-signal intensity region surrounded by a high-intensity signal region on T2-weighted imaging. Pathological findings indicated that the lesion was a venous malformation. DISCUSSION: Although many studies have reported that venous malformations have a multilocular appearance, few have described the occurrence of unilocular lesions. Future investigations using magnetic resonance imaging and computed tomography are needed to increase the diagnostic accuracy for unilocular central vascular malformations of the jaw bone.

Dental fiberscope with navigation system for endodontic treatments.

We developed a dental fiberscope with a navigation system. The aim of this study is to direct the position of the tip of the endoscope fiber in the root canal via our navigation system. The distinguishing characteristic of our system is that it could be particularly practical in narrow spaces, such as those involving endodontic treatment typical of root canals. We were subsequently able to precisely indicate the relation of the position between the device and the teeth on the 3D model on the monitor. We inspected our navigation system using both the phantom model and the reconstructed 3D model. From this we could comprehend the relation of the position between the teeth and the device, and aim precisely at the lesion. If we are able to realize the correct position of the endoscope, we can safely and accurately deliver laser irradiation to the lesion. Consequently, the application of the endoscopic navigation system could increase the success rate for root canal treatments with recalcitrant lesions.

Balloon-occluded retrograde transvenous obliteration of varices: focusing on the portal hemodynamics and the recent techniques.

PURPOSE: To evaluate the recent topics of Ballloon-occluded retrograde trasnvenous obliteration(B-RTO). METHOD: We overviewed the recent scientific papers regarding B-RTO. RESULT: B-RTO is a treatment method for occluding varices retrogradely using a sclerosing agent under balloon occlusion of a major draining vein. It has been recognized as an effective treatment method for gastric varices. Hepatic function reserve is improved and liver volume is increased after B-RTO. In recent years, various technical options, such as plug-assisted retrograde transvenous obliteration, coil-assisted retrograde transvenous obliteration, or foam B-RTO, have also been reported. In performing B-RTO, portal hemodynamics must be thoroughly examined radiologically. Judging the classification of the grade of collateral venous hemodynamics is important to select the appropriate embolization technique of B-RTO and to successfully occlude varices. Finally, the word "portosystemic shunt syndrome" has been proposed and the condition should be considered while selecting a treatment for gastric varices. CONCLUSION: B-RTO is effective for gastrointestinal varices and portosystemic shunts.