Tokyo Dental College Research Articles

The use of concomitant medications on nephrotoxicity associated with teicoplanin: A retrospective observational study

BackgroundTeicoplanin (TEIC) is a nephrotoxic agent. However, little is known about the effects of concomitant medications on nephrotoxicity. In this study, we investigated the effects of concomitant drugs on nephrotoxicity. MethodsA retrospective observational case-control study was conducted on patients (≥18 years) who started TEIC at the Tokyo Dental College, Ichikawa General Hospital, between January 2013 and April 2023. The primary outcome was nephrotoxicity, defined as an increase in serum creatinine levels of ≥50 % or ≥0.5 mg/dL from baseline. Logistic regression analysis was used to determine the risk factors for nephrotoxicity associated with TEIC. In addition, we investigated the relationship between nephrotoxicity and predicted free TEIC concentrations. ResultsOf 305 patients, 43 (14.1 %) developed nephrotoxicity. The multivariate logistic regression analysis identified that serum albumin (odds ratio [OR] = 0.50, 95 % confidence interval [CI] 0.27–0.89, p = 0.02), concomitant use of loop diuretics (OR = 2.22, 95 % CI 1.10–4.59, p = 0.03), antivirals (OR = 3.24, 95 % CI 1.32–7.62, p < 0.01), and vasopressors (OR = 2.57, 95 % CI 1.10–5.78, p = 0.03) were the associated risk factors for nephrotoxicity in patients administered with TEIC. In 216 patients, predicted TEIC concentrations were 3.6 [interquartile range (IQR), 2.6–4.9] μg/mL in the nephrotoxicity group versus 3.6 [IQR, 2.5–4.7] μg/mL in the non-nephrotoxicity group, with no significant difference (p = 0.69). ConclusionOur results indicate the importance of modifying the concomitant use of loop diuretics, antivirals, and vasopressors.

Pathological examination of factors involved in PD-L1 expression in patients with oral tongue squamous cell carcinoma

BackgroundTumor tissues comprise cancer cells and stromal cells, and their interactions form the cancer microenvironment. Therefore, treatments targeting cells other than cancer cells are also actively being developed, and among them, treatment targeting PD-1, an immune checkpoint molecule that is important in tumor immune evasion, has also been indicated for head and neck cancer. PD-L1, a ligand of PD-1, is expressed in both tumor cells and stromal cells, and the scoring system based on the combined positivity rates of both types of cells, the combined positive score (CPS), is used for predicting treatment effect. However, much is unknown regarding the expression of PD-L1. In this study, we histopathologically examined factors controlling the expression of PD-1/PD-L1. This study included 37 patients who underwent resection surgery for tongue squamous cell carcinoma in the Department of Oral and Maxillofacial Surgery at Tokyo Dental College Suidobashi Hospital. The expression levels of PD-L1, α-SMA, and p53 were assessed by immunohistochemical staining.ResultsSeven participants had CPS ≥ 20, twenty-four participants had 1 ≤ CPS < 20, and six participants had CPS < 1. The overall positivity rate of α-SMA, a marker for cancer-associated fibroblasts (CAFs), was 27% (10/37 participants), and the positivity rates of α-SMA for the three CPS groups were 85.7% (6/7 participants), 16.7% (4/24 participants), and 0% (0/6 participants), respectively. In addition, the overall positivity rate of p53 was 37.8% (14/37 participants), and the positivity rates of p53 for the three CPS groups were 71.4% (5/7 participants), 37.5% (9/24 participants), and 0% (0/6 participants), respectively.ConclusionsThe expression of PD-L1 demonstrated an association with α-SMA and p53 positivity. In addition, compared with the expression of p53, the expression of α-SMA demonstrated a higher association with PD-L1 expression in patients with a high CPS. The abovementioned findings suggest that the interactions between CAFs, cancer cells, and immunocompetent cells may regulate the expression of PD-L1.

Fluorescence Visualization-Guided Surgery Improves Local Control for Mandibular Squamous Cell Carcinoma

BackgroundLocal recurrence is common in mandibular squamous cell carcinoma. Fluorescence visualization is a non-invasive technology that can detect oral epithelial dysplasia around mandibular squamous cell carcinoma, and it can potentially reduce local recurrence. PurposeThe purpose of this study was to measure and compare local control between fluorescence visualization-guided surgery and conventional surgery for patients with Stages I or II mandibular SCC. Study design, setting, sampleThis retrospective cohort study was conducted at Tokyo Dental College, Chiba Hospital, or Chiba Dental Center. The medical records of mandibular squamous cell carcinoma patients from 2000 to 2021 were analyzed. Patients from any sex and 18 years of age or older with complete records who received surgery for mandibular squamous cell carcinoma in the early stages were included in this study. Predictor variableThe predictor variable was operative treatment and was divided into two groups, conventional or fluorescence visualization-guided surgery. Outcome variablesThe outcome variable is 5-year local control defined as no recurrence at or within 20 mm of the surgical site. CovariatesCovariates included demographic variables of age, sex, clinical and pathological characteristics, forms of resection, lifestyle, and quality of life. AnalysisData analysis was performed by carrying out chi-square tests. Survival outcome was performed by the Kaplan-Meier method, which was used to calculate and stratify the log-rank test.; P-values <0.05 indicated statistical significance. ResultsThis study sample was composed of 56 subjects with a mean age of 68.5 years old (SD 13.7), and 33 (58.9%) were female. There were 36 (64.3%) and 20 (35.7%) subjects in the conventional and fluorescence visualization-guided surgery groups. The characteristics and quality of life did not differ significantly between the two groups. Five-year local control with fluorescence visualization-guided surgery was statistically significantly higher than conventional surgery (P=0.04, 94.4% vs. 77.2%). Multivariate analysis for local control rate only identified fluorescence visualization-guided surgery (P=0.004; hazard ratio=0.11, 95% confidence interval=0.46, 0.88). Conclusions and RelevanceOn mandibular squamous cell carcinoma, local control was 94.4% in fluorescence visualization-guided surgery vs. 77.2% in conventional surgery. For mandibular squamous cell carcinoma at stages I and II, fluorescence visualization-guided surgery was associated with improved local control.

The use of cetuximab for oral cancer and adverse events with different treatment regimens: A single‐center retrospective study over an 11‐year period

AbstractBackgroundThe aim of this retrospective study was to assess the use and safety of cetuximab (C‐mab) monotherapy or combination therapy with various regimens for treating oral cancer in our hospital.MethodsThe study comprised 53 patients diagnosed with oral cancer who underwent chemotherapy with C‐mab between January 2013 and December 2022 at the Oral Cancer Center, Tokyo Dental College. In total, 68 regimens were analyzed. The cumulative rate was determined by analyzing the timing and incidence of adverse events (AEs) with each regimen using a Kaplan–Meier curve.ResultsThe treatment regimens administered included the following: induction C‐mab + paclitaxel + carboplatin (ICT‐PCE, n = 7), C‐mab + radiotherapy (RT) (n = 22), C‐mab + cisplatin + fluorouracil (n = 7), C‐mab + paclitaxel + carboplatin (n = 1), C‐mab + paclitaxel (n = 16), C‐mab maintenance (n = 11), and four other cases. The total number of doses administered was 895.ConclusionsThis retrospective study investigated the effectiveness of treatment regimens containing C‐mab for oral cancer and adverse reactions to these regimens. C‐mab is a crucial component of oral cancer treatment when used in multidrug therapy. C‐mab containing regimens may result in direct or indirect AEs. Ongoing, rigorous monitoring is essential to mitigate these events. Partnering with other departments can help to limit their severity.

Clinical Results of a Trifocal Toric Intraocular Lens Using the Holladay Total Surgically Induced Astigmatism Formula for Correcting Low Corneal Astigmatism in Japanese Patients.

To evaluate the effectiveness and safety of the AcrySof IQ PanOptix toric intraocular lens (IOL) with cylinder power of 1.0 D (TFNT20) in a Japanese population with low corneal astigmatism and compare with historical control data for nontoric IOLs. Tokyo Dental College Suidobashi Hospital, Tokyo, Japan. Prospective, single-center study. Patients ≥20 years old received TFNT20 IOL in at least 1 eye based on Alcon Toric calculator (Holladay Total surgically induced astigmatism). Effectiveness endpoints included the percentage of eyes with refractive cylinder ≤0.25 D at 30-60 days after surgery, which was compared with a historical control threshold rate of 29.2% for nontoric IOLs and refractive cylinder ≤0.50 D. Monocular uncorrected distance visual acuity (UDVA; 5 m), uncorrected intermediate visual acuity (UIVA; 60 cm), uncorrected near visual acuity (UNVA; 40 cm), and adverse events were evaluated. Of 41 eyes implanted with TFNT20 IOLs, 37 eyes (90%) achieved refractive cylinder ≤0.25 D at 30-60 days after surgery, demonstrating the superiority of TFNT20 compared with historical data (P<0.0001). Refractive cylinder of ≤0.50 D was achieved by 41 eyes (100%). At 30-60 days, mean ± SD monocular CDVA was -0.15 ± 0.07 logMAR, UDVA was -0.09 ± 0.09 logMAR, UIVA was -0.00 ± 0.07 logMAR, and UNVA was 0.03 ± 0.07 logMAR. Six eyes (15%) had elevated postoperative intraocular pressure, which returned to normal and was not device-related. TFNT20 IOLs successfully reduced postoperative refractive cylinder and provided good distance, intermediate, and near uncorrected VAs in Japanese patients with low corneal astigmatism.

Incidence and Clinical Features of Immunologic Rejection After Deep Anterior Lamellar Keratoplasty.

The aim of this study was to investigate the incidence and clinical features of immunologic rejection after deep anterior lamellar keratoplasty (DALK). This study included 411 patients (464 eyes, median age [interquartile range; IQR] 55.8 years [36.1-69.5]) who underwent DALK at Tokyo Dental College between June 1997 and 2021. Of 411 patients, 24 (24 eyes [5.2%], 51.9 years [IQR 31.6-65.4]) developed immunologic rejection. We characterized the clinical features, risk factors associated with immunologic rejection, and prognosis. The interval between DALK and immunologic rejection was 14.5 (range, 5-78) months. Immunologic rejection occurred after cessation/reduction of topical steroid in 9 (47.4%) and suture removal in 4 eyes (21.1%). The postoperative duration of topical steroid use in eyes with immunologic rejection was significantly shorter (10.0 months, [IQR 6.0-14.0]) than those without immunologic rejection (28.3 [IQR 15.8-42.7], P = 0.001). Immunologic rejection manifested as stromal edema in 19 (100.0%), ciliary hyperemia in 17 (89.5%), keratic precipitates in 13 (68.4%), epithelial edema in 13 (68.4%), infiltration in 9 (47.4%), corneal opacity in 4 (21.1%), and Descemet membrane detachment in 2 eyes (10.5%). After treatment, corneal clarity was restored in 17 eyes (89.5%); however, immunologic rejection led to corneal endothelial decompensation in 2 eyes (10.5%). Endothelial cell density decreased from 1795.7 ± 722.6 to 1651.6 ± 655.6 cells/mm 2 after immunologic rejection ( P = 0.074). Post-DALK immunologic rejection was associated with specific clinical triggers such as reduction/cessation of topical steroids or suture removal.

Characteristics of Mandibular Arch Forms in Patients with Skeletal Mandibular Prognathism.

Arch forms in orthodontics are considered to affect occlusal stability. This study's subjects were 47 patients (Class III S group) who visited the Chiba Dental Center of Tokyo Dental College and were surgical orthodontic cases, and 60 patients with Class I malocclusion were selected as the control group. A mandibular model of each subject was plotted with each tooth on a digitizer. The clinical bracket points of each tooth were plotted, and intercanine and intermolar measurements were taken. The least squares method was used to fit a quartic equation, and the arch form was drawn. The Class IIIS group was divided by Wits appraisal and facial pattern into a dolichofacial or brachyfacial pattern, and arch forms were compared. The results show that the Class IIIS group had a significantly smaller intermolar width, canine depth, and molar depth and a significantly larger canine W/D ratio. In those with a dolichofacial pattern, the anterior curve of the arch form tended to be flat and the posterior curve narrower. This is because, in skeletal mandibular prognathism, the mandibular anterior shows lingual tipping, and the molars show palatal tipping due to dental compensation, and it was inferred that this tendency was higher in high-angle cases.

Morphological Evaluation of Cranium Facial Asymmetry in Class III Malocclusion Patients

The maxillofacial region of patients with facial asymmetry is deformed not only in the mandible but also in the maxilla, suggesting that the head region may also be deformed. Therefore, in this study, skeletally originated mandibular prognathism with facial asymmetry was evaluated in relation to cranial morphology. The cranial morphology of patients who visited the Chiba Dental Center of Tokyo Dental College and were diagnosed with skeletal mandibular prognathism with facial asymmetry (asymmetry group: ANB 0° or less; Menton deviation 4 mm or more; 30 subjects) and without facial asymmetry (symmetry group: ANB less than 0°; Menton deviation less than 3 mm) was measured and evaluated. As a method, the length and area of the cranium were measured using axial cephalometric radiographs. In the asymmetry group, there was a significant difference in the left–right difference in the long diameter of the posterior part of the cranium compared to the symmetry group (p = 0.009). The asymmetry group also had significant differences in the central and occipital areas of the cranium on the left and right sides compared to the symmetry group (p &lt; 0.001). In the asymmetry group, the direction of Menton deviation and the direction of head region deviation coincided in about 70% of the cases. There was also a positive correlation between head deviation and the amount of Menton deviation. The results of this study suggested that patients with facial asymmetry had greater head deformity than patients without facial asymmetry.

Intraoral Minor Salivary Gland Tumors: A Retrospective, Clinicopathologic, Single-Center Study of 432 Cases in Japan and a Comparison with Epidemiological Data.

Intraoral minor salivary gland tumors are relatively rare lesions with histological subtypes not commonly found in major salivary glands. This study aimed to retrospectively evaluate the clinicopathologic features of intraoral minor salivary gland tumors from the Tokyo Dental College Hospital, Japan, and compare them with findings from other epidemiological studies. We conducted a retrospective clinicopathologic evaluation of 432 cases of intraoral minor salivary gland tumors [161 male (37.3%) and 271 female (62.7%) patients; mean age: 52.5 and 48.6years for males and females, respectively; age at diagnosis: 7-87 (mean: 50.1) years] from the Tokyo Dental College Hospital between 1975 and 2022, including 283 benign tumors (65.5%) and 149 malignant tumors (34.5%). The most common benign tumor was pleomorphic adenoma (n = 239), whereas mucoepidermoid carcinoma was the most common malignant tumor (n = 74). The mean age of patients with benign and malignant tumors was 48.4 and 53.2years, respectively, with patients with malignant tumors being significantly older (P = 0.0042). The mean age of patients with malignant tumors was significantly higher in males (56.7years) than in females (50.9years) (P = 0.0376), although the mean age of patients with benign tumors did not differ by sex. Tumors were commonly located in the palate [250 cases (57.9%)]. Benign tumors were more frequent in the palate, upper lip, and buccal mucosa, whereas malignant tumors were more frequent in the palate, floor of the mouth, buccal mucosa, and retromolar area. Understanding the features of intraoral minor salivary gland tumors is useful for diagnosis. Our study provides important epidemiological data (patient differences in age at occurrence, sex, and site of origin) that will inform clinicians and researchers.

A clinico-statistical study of factors associated with intraoperative bleeding in orthognathic surgery

BackgroundExcessive bleeding is a major intraoperative risk associated with orthognathic surgery. This study aimed to investigate the factors involved in massive bleeding during orthognathic surgeries so that safe surgeries can be performed. Patients (n=213) diagnosed with jaw deformities and treated with bimaxillary orthognathic surgery (Le Fort I osteotomy and bilateral sagittal split ramus osteotomy) in the Department of Oral and Maxillofacial Surgery at the Suidobashi Hospital, Tokyo Dental College between January 2014 and December 2016 were included. Using the patients’ medical and operative records, the number of cases according to sex, age at the time of surgery, body mass index (BMI), circulating blood volume, diagnosis of maxillary deformity, direction of maxillary movement, operative duration, incidence of bad split, injury of nasal mucosa, and blood type were analyzed.ResultsThe results revealed that BMI, circulating blood volume, nasal mucosal injury, and operative time were associated with the risk of intraoperative massive bleeding in orthognathic surgeries. Chi-square tests and binomial logistic regression analyses showed significant differences in BMI, circulating blood volume, direction of maxillary movement, operative duration, and injury to the nasal mucosa. Operative duration emerged as the most important risk factor. Furthermore, a >4-mm upward migration of the posterior nasal spine predicted the risk of massive bleeding in orthognathic surgery.ConclusionsThe upward movement of the maxilla should be recognized during the preoperative planning stage as a risk factor for intraoperative bleeding, and avoiding damage to the nasal mucosa should be considered a requirement for surgeons to prevent massive bleeding during surgery.

Japanese Maxillary First Molar Root Canal Morphology: An Ultrastructural Study Using Micro-Computed Tomography

The present study used ultra-high-resolution micro-computed tomography (CT) to clarify the classification of root canal morphologies and the incidence of accessory canals in the maxillary first molar mesiobuccal (MB) root. Aspects of the relationship with root canal reinfection during or after molar endodontic treatment were also investigated. Molar three-dimensional structure, pulp cavity, and accessory canals were examined on micro-CT images of 100 Japanese maxillary first molars from the collection at the Department of Anatomy, Tokyo Dental College. The most common Vertucci’s classification of the main root canal of the Japanese maxillary first molar mesial root canal was Type I, followed by Type V. Accessory canal incidence was 75.0%, which was higher than previously reported; however, the majority of such canals were within the apical 3 mm. Many accessory canals were observed even with the single canals of Type I, suggesting that the existence of accessory canals should always be considered even if diagnostic imaging clearly shows a Type I classification.

Frequency of Odontogenic Tumors: A Single Center Study of 1089 Cases in Japan and Literature Review

Several attempts have been made to classify odontogenic tumors; however, the need for a uniform international classification system led the World Health Organization (WHO) to present a classification of odontogenic tumors in 1971. We aimed to evaluate the number and types of odontogenic tumors examined at the Tokyo Dental College Hospital in Japan to determine the frequency and types of odontogenic tumors, based on the 2017 WHO classification system, as this information has not been reported previously in Japan. We also compared the results of our evaluation with those reported in previous studies. We conducted a clinicopathological evaluation of odontogenic tumors examined at the Tokyo Dental College Hospital between 1975 and 2020. This included an analysis of 1089 cases (malignant, n = 10, 0.9%; benign, n = 1079, 99.1%) based on the 2017 World Health Organization Classification of Head and Neck Tumors. We identified 483 (44.3%), 487 (44.7%), and 109 (10.0%) benign epithelial odontogenic, mixed odontogenic, and mesenchymal tumors, respectively. The most common tumor types were odontoma (42.5%) and ameloblastoma (41.9%). Of the 1089 cases, 585 (53.7%) and 504 (46.3%) were male and female patients, respectively. Ameloblastoma and ameloblastic fibroma occurred more commonly in male patients, whereas odontogenic fibroma and cemento-ossifying fibroma affected female patients primarily. The age at diagnosis ranged from three to 87 (mean, 29.05) years. In 319 (29.3%) patients, the age at diagnosis ranged from 10 to 19years. Ameloblastoma and odontoma were the most common tumor types among patients in their 20s and those aged 10-19years, respectively. In 737 (67.7%) and 726 (66.7%) patients, the tumors were located in the mandible and posterior region, respectively. Ameloblastoma was particularly prevalent in the posterior mandible. Odontogenic tumors are rare lesions and appear to show a definite geographic variation.

Clinical evaluation of periodontal pathogen levels by real-time polymerase chain reaction in peri-implantitis patients

ObjectiveThe mechanisms underlying the onset and progression of peri-implantitis are similar to those of periodontitis, and the causative bacteria are believed to similar. Previous studies support an association between peri-implantitis and periodontal pathogen. Thus, we investigated the bacterial flora of peri-implantitis patients in comparison to those of healthy implant and periodontitis patients.Materials and methodsIn total, 70 patients visiting Tokyo Dental College Chiba Hospital were divided into four groups: healthy, periodontitis, healthy implant, and peri-implantitis. For each group, the following five periodontal pathogens were detected using real-time polymerase chain reaction: Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, and Prevotella intermedia.ResultsThe average copy number of total bacteria was significantly higher in the periodontitis group than in the other groups. P. gingivalis was detected in the periodontitis and peri-implantitis groups at levels as high as 18.92% and 12.29%, respectively, and P. intermedia was found in the peri-implantitis group at a rate of 2.06%. Nevertheless, periodontal pathogens were generally detected at lower levels in the peri-implantitis group than in the periodontitis group.ConclusionWe found lower bacterial counts in the peri-implantitis group relative to the periodontitis group. Our results suggest that the peri-implant tissue is less resistant to bacteria, so even a small number of bacteria can be a risk factor for peri-implantitis and the causative agent of peri-implantitis can be bacteria other than periodontal pathogen.

Communicating Branch of the Mental Nerve and Facial Nerve

As peripheral branches of the mandibular nerve, the mental nerve and facial nerve communicate with each other. However, investigations have not always been described in the classic anatomical texts. It remains unknown how nerve fibers of this communicating branch converge at the micro level. Thus, the objective of the present study was to observe in detail the macro and micro levels of the communicating branch of mental and facial nerves. We used five cadavers (10 samples) to conduct experiments in anatomical practice at Tokyo Dental College. A macroscopic observation was made, and the communicating branch of the mental and facial nerves was removed as a single mass. We created serial sections of this branch using the standard method and observed communicating branches of these two nerves under microscopy. As a result, the communicating branch of the mental and facial nerves was completely fused at the perineurium level. It has been reported that the mental nerve includes a small amount of autonomic nerve fiber. As for these findings, similar findings were observed for all 5 bodies and 10 sides. Thus, we believe that autonomic nerve fibers derived from the facial nerve converge with the mental nerve via this communicating branch.

Comparative Study of Morphology and Distribution of Valves in Human Retromandibular Vein.

The objective of this study was to analyze the distribution and morphology of the valves in the human retromandibular vein. The retromandibular, internal thoracic, azygos, femoral, and brachial veins were harvested from 46 cadavers donated to the Department of Anatomy at Tokyo Dental College for dissection. The frequency of the valves in each vein, the length of the cusps, and the thickness of the vein itself were measured. Valves were present at high frequency (92.1%) in the veins of the limbs and had cusps at least twice as long as the internal diameter of the vein. Veins in the trunk contained a lower frequency of valves, with cusps that tended to be shorter (1.60±0.77) than those of the venous valves in the limbs (2.12±0.60). The valves of the retromandibular vein tended to resemble venous valves in the trunk in terms of both frequency and morphology. The main function of venous valves in the limbs is to prevent retrograde flow. Conversely, valves in the veins of the trunk and retromandibular vein play a role in retaining blood in the veins, and their relationship to other veins means that they can cause major hemorrhage.

Countermeasure and opportunistic screening systems for oral cancer.

Tokyo Dental College started oral cancer screening in cooperation with a local dental association in 1992. Reveal the usefulness of Countermeasure and Opportunistic Screening Systems for Oral Cancer. The actual results of countermeasure and opportunistic oral cancer screening systems are reported. Countermeasure screening for the public was performed in each region, and opportunistic screening was performed in a general dental clinic of a cooperating physician. In countermeasure screening, 19,721 persons were checked from 1992 to 2018; the gender ratio was 1:3. The close examination rate was 4.45%. The detection rates of oral cancer and oral potentially malignant disorders were 0.13% and 1.85%, respectively. In opportunistic screening, 29,912 persons were checked from 2006 to 2018; the gender ratio was 2:3. The close examination rate was 2.33%. The detection rates of oral cancer and oral potentially malignant disorders were 0.08% and 2.15%, respectively. The close examination rate was significantly lower in opportunistic screening than in countermeasure screening. The oral cancer detection rates and the positive predictive value for cancer were equivalent. In addition, the detection rate of oral potentially malignant disorders was significantly higher in opportunistic screening than in countermeasure screening. Oral cancer detection rates were equivalent between countermeasure and opportunistic screenings, and opportunistic screening were more effective on number of participants and the close examination rate, and the detection rate of oral potentially malignant disorders.

Ten-year adherence to continuous positive airway pressure treatment in patients with moderate-to-severe obstructive sleep apnea

PurposeThis study aimed to evaluate the 10-year adherence to and identify the predictors of dropout from continuous positive airway pressure (CPAP) treatment for patients with moderate-to-severe obstructive sleep apnea (OSA).MethodsWe retrospectively analyzed the continuity, dropout, or other behaviors of 181 patients who initiated CPAP treatment at the Tokyo Dental College Ichikawa General Hospital from January 2003 to June 2005.ResultsAmong a total of 181 patients, 56 (30.9%) dropped out of the treatment. Among the 125 patients who did not dropout, 54 continued CPAP treatment for > 10 years, 16 completed the treatment with OSA improvement, and 7 could not complete the treatment owing to unavoidable reasons such as death, dementia, hospitalization for serious illness, or migration to other countries. Further, 47 patients moved to another facility, whereas 1 patient purchased a CPAP device and stopped visiting our facility. Among the 56 patients who dropped out, approximately 50% of the patients dropped out within a year, and all dropped out within 76 months. Comparing demographics, OSA parameters, and CPAP parameters between the patients who did and did not drop out of the treatment, Cox regression analysis indicated that body mass index (BMI) and the first-month utilization rate were clinical variables that were independently associated with discontinuation of CPAP treatment.ConclusionThe results of this study show that BMI and the first-month utilization rate of CPAP treatment are the predictors of the long-term adherence to this treatment.

Survey on Condition and Orthodontic Treatment of Maxillary Lateral Incisors in Patients with Cleft Lip and Palate.

The aim of this study was to investigate the condition of the maxillary lateral incisors and evaluate the methods used for cleft closure in patients with cleft lip and palate, including the treatment of the maxillary lateral incisors. A total of 214 patients (260 clefts) with alveolar clefts who had started Phase II treatment and entered the maintenance period at the Department of Orthodontics at Tokyo Dental College, Chiba Hospital, between 1975 and 2014 were included. Panoramic, intraoral, and occlusal radiographs, as well as intraoral photographs and medical records, were used to investigate cleft classification, the presence or absence and location of maxillary lateral incisors, and frequency and treatment method for peg lateral incisors in the cleft region. There were more unilateral cleft cases (78.5%) than bilateral cleft cases. The prevalence of congenital absence of the maxillary lateral incisors was similar between unilateral (53.0%) and bilateral cases (53.3%). Peg laterals occurred frequently, with 89.9% occurring in unilateral cases. The maxillary lateral incisors were more commonly found in the secondary than in the primary palate. The number of non-extraction cases was larger than that of extraction cases, regardless of cleft type or the location of the peg laterals. In many cases, the peg laterals were treated with non-extraction and space closure or crown modification. These results suggest that, depending on their condition, the peg laterals should be preserved as much as possible in devising a treatment plan.

A Case of Fibrolipoma of the Hard Palate

An extremely rare case of fibrolipoma in the hard palate is presented and discussed with reference to the literature. An 85-year-old woman visited the Tokyo Dental College Chiba hospital in September 2016 with the chief complaint of a mass in the hard palate. The patient had first become aware of this mass several years earlier. An examination at another hospital in June 2009 resulted in a clinical diagnosis of lipoma. Regular examinations followed every 6 months until September 2014, at which time she stopped attending these appointments because there was no change. In August 2016, however, the patient realized that the tumor was increasing in size. Although there was no pain, awareness of a foreign body in the oral cavity when eating or talking was increasing, so she decided to visit our clinic for detailed examination and treatment. At this point, the mass extended from the center to the left side of the hard palate. It measured 15 mm along the major axis, and had a clear border; nearly spherical, its surface was smooth and glossy, and was of a slightly yellowish color. The mass was painless, elastic, and soft. Computed tomography and magnetic resonance imaging revealed a tumorous lesion. Based on a clinical diagnosis of lipoma, it was subsequently excised under general anesthesia in January 2017. The tumor lay under the palatal mucosa, extending from the center to the left side of the hard palate. It was surrounded by a single-layered membranous structure, and had not adhered to the surrounding tissues. Healthy palatal mucosa and periosteum were also removed en bloc with the tumor within a safety margin of approximately 5 mm. No pressure absorption of palatine bone was seen. Histopathologically, proliferation of mature adipose tissue was observed. This was surrounded by a thin, single-layer membrane within the subepithelial connective tissue, which was covered by stratified squamous epithelium. Proliferation of fibrotic connective tissue was seen between the adipocytes. The final diagnosis was fibrolipoma. To date, at 18 months postoperatively, no recurrence has been observed and progress has been satisfactory.

FREQUENCY OF HEPATITIS B VIRUS AND HEPATITIS C VIRUS IN PATIENTS UNDERGOING VARIOUS DENTAL PROCEDURES

Objective: To determine the frequency of hepatitis B virus and hepatitis C virus in patients undergoing various dental procedures at Tokyo Yaesu Dental Clinic and Tokyo Dental College Japan. Materials &amp; Methods: In this descriptive study, we determined the frequency of HBV and HCV by screening the patients for HBs antigen and HCV antibody in blood serum before going for any dental procedures. Data were recorded from December 1999 to 2009(9 years &amp; 8 months) in the Tokyo Yaesu Dental Clinic whereas in Tokyo Dental College Japan from October 2006 up to May 2008 (1 year and 8 months).&#x0D; Results: In this study, we assessed 2,181 patients for HBs, out of which 13 (0.60%) cases were found positive for HBs at Tokyo Yaesu Dental Clinic, and out of 3216 patients 33 (1.02%) patients were found positive for HBs antigen at Tokyo Dental College. On another hand 31 (1.42%) patients out of 2181 were found positive of HCV antibody at Tokyo Yaesu Dental Clinic and 45 numbers of cases (1.43%) were found positive for HCV antibody at Tokyo Dental College. Most of the patients were found to be in the 6th and 7th decade of life.&#x0D; Conclusion: Screening for HBV and HCV should be mandatory for every patient going through any invasive and non- invasive dental procedures. Furthermore, sterilizations and standard precautionary protocols must also be observed at Dental clinics and hospitals.&#x0D;