Tokyo Dental College Research Articles

Surgical Periodontal Therapy at Tokyo Dental College Suidobashi Hospital: A Statistical Profile in 2010-2011

The aim of the present study was to investigate the profile of surgical periodontal therapy performed at the Suidobashi Hospital of Tokyo Dental College, during the period of April 2010 through March 2011. A total of 112 periodontal surgeries in 69 patients (mean age: 51.4 years; 28 men and 41 women) were registered for the data analysis. The surgical interventions performed by 17 dentists comprised 79 cases of open flap debridement, 27 cases of periodontal regenerative therapy with enamel matrix derivative and 6 cases of periodontal plastic surgery. Eighty percent of the surgical sites were in the molar region and 41 cases had furcation involvement. In these patients, an improvement in oral hygiene status was observed prior to surgery: the mean plaque score of 45% at initial visit was significantly reduced to 31% after initial periodontal therapy (p<0.01). At sites that subsequently received open flap debridement or periodontal regenerative therapy, the mean probing depth and clinical attachment level after initial therapy was 6.4 mm and 7.6 mm, respectively. These values were significantly lower than those at initial visit (p<0.01). Lower prevalence of sites with positive bleeding on probing was observed after initial therapy. The initial periodontal therapy performed was considered to be effective in improving the periodontal condition of the sites prior to surgery. More effort, however, is indicated in improvement of patient oral hygiene status.

Analysis of copy number abnormality (CNA) and loss of heterozygosity (LOH) in the whole genome using single nucleotide polymorphism (SNP) genotyping arrays in tongue squamous cell carcinoma

Chromosomal loss of heterozygosity (LOH) is a common mechanism for the inactivation of tumor suppressor genes in human epithelial cancers. LOH patterns can be generated through allelotyping using polymorphic microsatellite markers; however, owing to the limited number of available microsatellite markers and the requirement for large amounts of DNA, only a modest number of microsatellite markers can be screened. Hybridization to single nucleotide polymorphism (SNP) arrays using Affymetarix GeneChip Mapping 10 K 2.0 Array is an efficient method to detect genome-wide cancer LOH. We determined the presence of LOH in oral SCCs using these arrays. DNA was extracted from tissue samples obtained from 10 patients with tongue SCCs who presented at the Hospital of Tokyo Dental College. We examined the presence of LOH in 3 of the 10 patients using these arrays. At the locus that had LOH, we examined the presence of LOH using microsatellite markers. LOH analysis using Affymetarix GeneChip Mapping 10K Array showed LOH in all patients at the 1q31.1. The LOH regions were detected and demarcated by the copy number 1 with the series of three SNP probes. LOH analysis of 1q31.1 using microsatellite markers (D1S1189, D1S2151, D1S2595) showed LOH in all 10 patients (100). Our data may suggest that a putative tumor suppressor gene is located at the 1q31.1 region. Inactivation of such a gene may play a role in tongue tumorigenesis.

Evaluation of factors associated with the anxiety and depression of female infertility patients

BackgroundBecause the primary aim of infertility treatment is to achieve pregnancy, mental health care during this treatment is often neglected. However, the inability to conceive children is stressful for couples throughout the world. Thus, the purpose of this study was to investigate factors related to the anxiety and depression of female infertility patients.MethodsParticipants included 83 Japanese women who initially visited the Reproduction Center of the Tokyo Dental College Ichikawa General Hospital to undergo testing and receive infertility treatment between February and April 2008. We administered two psychological tests, the Self-rating Depression Scale (SDS) test and the Hospital Anxiety and Depression Scale (HADS) test. We then examined the association of the test results with age, pregnancy and delivery history, employment status, duration of infertility, infertility treatment history, and male infertility.ResultsAs patient age increased, total HADS and depression scores also increased. No correlation was observed between duration of infertility and SDS or HADS scores. Results were similar when the presence and absence of delivery history was compared. Patients who underwent infertility treatment were more likely to have high HADS depression scores compared to patients who had not undergone treatment. Additionally, patients whose husbands were infertile had significantly lower total HADS and anxiety scores than those whose husbands were not infertile.ConclusionsAge and male infertility are factors that influence the presence of anxiety and depression in female infertility patients.

Effectiveness of Calvital®, a Calcium Hydroxide Formulation, on Persistent Apical Periodontitis Caused by Over-enlargement of Apical Foramen

This study aimed to evaluate the effectiveness of Calvital(®), which is a calcium hydroxide formulation, on persistent apical periodontitis caused by over-enlargement of the apical foramen. The study included patients referred to the Department of General Dentistry at Tokyo Dental College Suidobashi Hospital on a diagnosis of persistent apical periodontitis at an external dental clinic. Of them, 20 showing considerable enlargement of the apical foramina were included in the study. Complete disappearance of symptoms was observed in all patients after intracanal application of Calvital(®). We believe that this was due to effective wound-healing brought about the strong alkaline nature of this formulation. We regard Calvital(®) as a highly effective agent for root canal treatment of teeth with persistent apical periodontitis.

The Effects of Calcified Seaweed on Remineralization of Artificially Demineralized Dentin

The study investigated the remineralization effect of calcified seaweed with large amounts of calcium (Ca), magnesium (Mg), sodium (Na), fluorine (F) and phosphorus (P). Human third molars were used in the experiment with the approval of the Ethics Committee of Tokyo Dental College. Cementum was removed from the cervical area around the teeth exposing the dentin. Small dentin blocks were prepared and immersed in acetic acid-sodium acetate buffer for 24 hours. Samples were immersed in remineralized liquid or saliva solution with or without calcified seaweed for 2 weeks. Structural changes in remineralization, depth of demineralization and loss in mineral volume were evaluated by contact microradiogram (CMR). Qualitative analysis was carried out with electron probe microanalyzer (EPMA). Morphology of crystal was observed using high-resolution transmission electron microscopy (HR-TEM). CMR image analysis revealed that part of the samples immersed in the solutions underwent remineralization. However, there was no significant difference in the degree of remineralization. EPMA observation of dentin partly detected Ca and P but not Mg or F. HR-TEM analysis revealed changes in crystal structure caused by Mg and F, which influenced remineralization in a small amount.

Periodontal Conditions in Patients Requesting Dental Implant Treatment

Periodontal disease is considered a risk factor in dental implant treatment. The purpose of this study was to investigate the periodontal conditions in patients requesting dental implant therapy. A total of 169 patients visiting Department of Oral and Maxillo-Facial Implantology at Tokyo Dental College Chiba Hospital were targeted. The following intraoral parameters were measured in each patient: Community Periodontal Index (CPI) score, probing pocket depth (PPD), clinical attachment level (CAL) and bleeding on probing (BOP). Prevalence of patients with periodontal pockets was high: 38% and 28% of patients had a CPI score of code 3 and 4, respectively. Prevalence of teeth with one or more sites with PPD≥4mm was 27%. Moreover, clinical signs suggestive of periodontitis (PPD, CAL≥4mm) were found in 10-15% of tooth sites. Prevalence rates at sites with severe periodontal breakdown (PPD, CAL≥7mm) were 2-5%. These results further emphasize the importance of thorough periodontal assessment in patients prior to dental implant treatment.

Character Traits of Malodor Patients

Many patients visit oral malodor clinics because of malodors which are brought to their attention by friends and family, or because they note the behavior of people around them, they suspect a problem and develop a fear of having an oral malodor. However, only around 30% of such patients actually have levels of malodor high enough to bother other people. Many patients exhibit halitophobia symptoms, which present as self-perception of malodor, and thus have a strong obsession about their smell which results in distress. Here, we carried out a study on 300 outpatients who visited the Tokyo Dental College Chiba Hospital Odor Clinic. We used the Tokyo University Egogram (TEG) to elucidate character traits of affected outpatients and compared the occurrence of TEG types in these patients with those of normal individuals. We discovered that 10.4% of patients were A-dominant type, which was 10.6% lower than the 21.0% of normal individuals. On the other hand, 18.4% of patients were N-type (NP high, FC low), which was 9.9% higher than the 8.5% of normal individuals. Results revealed that very few of the malodor outpatients exhibited the trait that shows intelligence, calm judgment, and self-affirmation, and as a result enjoy their life. Instead, many of these patients tended to show high levels of kindness and appeared to be holding themselves back and exercising patience.

Two-year follow-up after implantation of diffractive aspheric silicone multifocal intraocular lenses

To evaluate the stability of visual performance after implantation of a diffractive aspheric silicone multifocal intraocular lens (MIOL). Thirty eyes of 15 patients received the Tecnis MIOL ZM900 (Abbot Medical Optics) after cataract extraction at Tokyo Dental College Suidobashi Hospital. The uncorrected and best-corrected distance visual acuities (UCDVA, BCDVA); uncorrected, distance-corrected and best-corrected near VAs (UCNVA, DCNVA and BCNVA); spherical equivalent refraction, spectacle independence, contrast sensitivity and posterior capsule opacification (PCO) were measured at 1 week; 1, 3 and 6 months; and 1 and 2 years postoperatively. Two years postoperatively, the UCDVA was 0.01 logMAR, BCDVA -0.09 logMAR, UCNVA 0.19 logMAR, DCNVA 0.1 logMAR and BCNVA 0.04 logMAR. There was no significant change from 1 week through 2 years. The percent of spherical equivalent refraction error within ± 0.5 diopter was 63.4% at 2 years. No patient required spectacles for reading; two patients have used spectacles for intermediate vision when necessary. One eye underwent Nd:YAG laser posterior capsulotomy because of PCO. The visual performance after implantation of the Tecnis MIOL was stable for 2 years. A low rate of PCO contributed to the long-term visual performance.

Development and Status of e-Learning Program at Tokyo Dental College

This article reports the development and current status of an e-Learning system (hereafter, referred to as "ELS") at Tokyo Dental College. The ELS was developed to promote self-study. In order to achieve this, all new students were encouraged to use a notebook PC, and an intramural IT environment providing full, wireless LAN Web access was established. One key aspect of the ELS is the inclusion of a series of organically integrated lectures. This system represents a new departure in the development of fully technology-integrated dental education, providing a program which allows the student to select "unified themes" which incorporate those tackled in the standard curriculum as "systematic subjects". Integrated learning is further enhanced, as the system contains "topic spaces" which allow access to all related topics and information throughout the entire system in order to support cross-sectional learning by each student. The system was developed based on the following 2 criteria: 1) there must be relevance to the standard syllabus; and 2) the contents must be relevant to problem-based training. The results have indicated that the ELS is effective and helpful to the students, and there are plans to expand the contents of the system. Further refinements of the system should make it even easier to use for both students and teachers.

Color Differences between Artificial and Natural Teeth in Removable Partial Denture Wearers

The purpose of this study was to investigate differences between natural tooth color and that selected for artificial teeth in partial dentures at our department with a view to establishing criteria for obtaining greater harmonization between colors. The participants in this study comprised partial denture wearers visiting the Department of Prosthodontics, Tokyo Dental College Chiba Hospital, in whom both artificial teeth and natural teeth were present in the maxillary anterior tooth area. Natural tooth color was measured according to VITA classical shade guide number using a dental color measurement apparatus. Artificial tooth color in partial dentures produced at our department was investigated by referring to medical records. Color of 28 participants' natural teeth and 345 participants' artificial teeth was investigated. Differences in color distribution between the natural and artificial tooth were analyzed using the Fisher exact test. The most frequent color of natural tooth was C-type, accounting for 39%, followed by D- at 32%, A-at 22% and B-type at 7%. In terms of artificial tooth color, A-type was the most common (97%). The color distribution of natural teeth differed significantly from that of artificial teeth in partial dentures. These results suggest that artificial tooth color did not harmonize with the color of the natural teeth in partial denture wearers.

Matching System within Clinical Training Facilities Group of Clinical Dental Training in Tokyo Dental College Chiba Hospital

Since clinical dental training became mandatory in April 2006, Tokyo Dental College Chiba Hospital has been offering the following two types of training system: 1. a single system, and 2. a clinical training facilities group system. The clinical training facilities group system consists of program B, in which residents are trained in a cooperation-type clinical training facility for 3-4 months, and program C, in which residents are trained in two cooperation-type clinical training facilities for 7-8 months. A matching system within the clinical training facilities group is applied to select and decide on the cooperation-type clinical training facility for residents. In this system, the ranking of resident candidates that a cooperation-type clinical training facility would like to accept, and the ranking of training facilities that candidates choose are matched. The present study investigated the matching system within the clinical training facilities group in 2006, 2007, and 2008. The rate of matching to their third choice was more than 90% in program B and about 80% in program C in each year, suggesting a high matching rate. The percentage of cooperation-type clinical training facilities accepting dental residents dropped due to a decrease in the number of such residents. The distribution of accepted cooperation-type clinical training facilities is concentrated in Chiba Prefecture where our hospital, the management-type clinical training facility, is located, and the neighboring prefectures.

Survey of Accidental Ingestion and Aspiration at Tokyo Dental College Chiba Hospital

The occurrence of accidental ingestion/aspiration and preventive measures were investigated at Tokyo Dental College Chiba Hospital. In addition, the characteristics of accidents at our hospital were analyzed by surveying the awareness of accidental ingestion/aspiration to utilize the data for prevention. Accidental ingestion accounted for about 30% of accidents that occurred at our hospital in fiscal 2008, but all ingested items were naturally excreted, and no accidental aspiration occurred. Accidental ingestion most frequently occurred when dental restorations were removed. Inlays and crowns were most frequently ingested, and dentists with 5 to less than 10 years of clinical experience tended to be involved in these accidents. According to the results of the questionnaire, removal of restorations was perceived as the treatment least likely to cause accidental ingestion/aspiration. Moreover, dentists who always took preventive measures against accidental ingestion/aspiration accounted for only 40% or less on average. To avoid accidental ingestion/aspiration, repeated courses and individual instruction for repeaters and the establishment of a surveillance system along with manuals to manage the violation should be emphasized.

Clinical Study of Temporary Anchorage Devices for Orthodontic Treatment

The aim of this retrospective study was to determine factors that might cause complications in use of temporary anchorage devices (TADs) for orthodontic anchorage. We investigated 904 TADs in 455 patients. Clinical diagnoses requiring orthodontic treatment were malocclusion, jaw deformity, various syndromes, cleft lip and palate and impacted teeth. All patients underwent surgery at Tokyo Dental College Chiba Hospital between November 2000 and June 2009. Three kinds of titanium screw of different diameter and length were used: self-drilling mini-screws (Dual Top Autoscrew® and OSAS®), pre-drilling micro-screws (K1 system®) and palatal screws (PIAS®). Mini-plates fixed with 2 or 3 screws (SAS system®) were also used for skeletal anchorage. Patients were aged between 8 and 68 years (25.7±9.8 years). A total of 460 screw-type and 444 plate-type TADs were used. These comprised the following: mini-plates, 444; self-drilling mini-screws, 225; pre-drilling micro-screws, 83; and palatal screws, 152. Each type of implant had a high success rate of over about 90%. Failure rates were as follows: micro-screws, 7%; mini-screws, 6%; palatal implants, 11%; and mini-plates, 6%. Inflammation rate occurring in soft tissue surrounding TADs was follows: plate-type, 7.6%; mini-screws, 1.3%; micro-screws, 0%; and palatal implants, 2.5%. Inflammation frequencies depended on degree of mucosal penetration. Granulation rate in soft tissue surrounding TADs occurred as follows: micro-screws, 5.7%; self-drilling mini-screws, 0%; palatal screws, 0.6%; plate-type, 0.9%. Both plate- and screwtype orthodontic implants showed excellent clinical performance.

56th Annual Meeting of the American Academy of Implant Dentistry and the World Congress of Oral Implantology 7 Abstracts, 2007

56th Annual Meeting of the American Academy of Implant Dentistry and the World Congress of Oral Implantology 7 Abstracts, 2007

Age estimation based on three-dimensional measurement of mandibular central incisors in Japanese

The purpose of this study was to investigate an age estimation method that considers gender as well as three-dimensional measurement of the components, specifically enamel and dentin. A total of 155 mandibular central incisors aged 12–79 years old which was chosen from the collection stored at the Department of Anatomy in Tokyo Dental College and had no opened apex, caries or restorative treatment, were examined. Samples were scanned using micro-CT HMX225 ACTIS4. Based on the sliced image data, three-dimensional structures were obtained and the volumes of enamel, dentin, and pulp cavity were measured. Regression equations for age estimation were then determined. The accuracy of age estimation equations for each region, volume ratio, and sex was assessed using the determination coefficient R 2 as well as the standard errors of estimated values. The root region alone had a comparable accuracy to that of the whole tooth and the crown region had a relatively lower accuracy. In the whole tooth and the crown region, slightly higher correlations were observed for pulp/tooth volume ratios in which enamel was excluded. Females tended to have higher accuracy compared to males. The estimated age was higher in males compared to females for the same volume ratio of the pulp cavity. The highest correlation in both genders with age was observed for the volume ratio of the pulp cavity to the whole tooth excluding the enamel (males, R 2 = 0.67; females, R 2 = 0.76). The 95% confidence intervals for the population regression showed different distributions for each sex. In the 95% prediction intervals for age estimation, females tended to have narrower intervals and higher accuracy compared to males. Therefore, the use of gender-specific equations is recommended for age estimation.

Root Coverage Technique with Enamel Matrix Derivative

Various periodontal plastic surgical techniques are employed in obtaining root coverage. Recently, the use of an enamel matrix derivative (EMD) has been reported in such treatment. We report 2 cases of root coverage surgery with a coronally positioned flap in combination with EMD (CPF+EMD) and connective tissue graft in combination with EMD (CTG+EMD). Case 1: The patient was a 25-year-old woman referred to Suidobashi Hospital, Tokyo Dental College for root coverage surgery on the lower right first premolar. Gingival recession was classified as Miller Class II, as no alveolar bone loss or loss of attachment was observed in the interdental area, although recession had progressed to the mucogingival junction. The patient was diagnosed with local gingival recession caused by excessive tooth brushing. Primary conservative treatment failed to reduce the gingival recession. Subsequently, root coverage surgery with CPF+EMD was carried out. As observation at the 1-year follow-up revealed complete root coverage and no recurrence of root exposure or subjective symptoms, the postoperative course was considered to be favorable. Case 2: The patient was a 39-year-old woman referred to Suidobashi Hospital, Tokyo Dental College for root coverage surgery on the lower left canine. Gingival recession was classified as Miller Class II. Root coverage surgery with CTG+EMD was carried out. As observation at the 2-month follow-up revealed complete root coverage and no recurrence of root exposure, the postoperative course was considered to be favorable. These 2 cases indicate the effectiveness of root coverage surgery with CPF+EMD and CTG+EMD.

Clinical Care Provided on Post-graduate Dental Clinical Training Course at Tokyo Dental College Chiba Hospital, Department of General Dentistry

Number of patients assigned to dental residents, course of treatment and number of various technical tasks performed as described in the Reports on Clinical Training of Dentists published by the Department of General Dentistry, Tokyo Dental College Chiba Hospital since its establishment in 2002 were compared between before (2003-2005) and after (2006-2007) clinical training was made mandatory, and the state of clinical residency evaluated. Number of patients assigned generally increased, and mean number of patients treated by each resident in 2007 (15.08) was approximately 2 times higher than that in 2003 (8.47). Total number of treatments was 1.38 times higher in 2007 than in 2003, and periodontal treatment accounted for approximately 40% of all treatment both before and after clinical training became mandatory. Number of technical tasks in 2004-2007 was less than half the peak in 2003. To further improve clinical training, evaluation and implementation of effective approaches is necessary to secure an adequate number of patients, widen the variety of cases and increase the number of technical tasks.

Pupil sizes in different Japanese age groups and the implications for intraocular lens choice

To observe pupil sizes with near and distance vision under different lighting conditions in different Japanese age groups. Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital, Tokyo, Japan. Using an open view-type infrared video pupillometer, the horizontal and vertical pupil sizes were measured prospectively with subjects gazing at 30 cm or 3 m targets under photopic (illumination 500 lux) and mesopic (illumination 5 lux) conditions. The results were analyzed by age, and the benefits with various multifocal IOLs were evaluated. The study comprised 140 eyes (70 subjects; 14 to 94 years). The mean +/- standard deviations of photopic vertical pupil sizes when gazing far/near decreased from 3.77 +/- 0.23/3.50 +/- 0.33 mm (<20 years) to 2.20 +/- 0.30/1.95 +/- 0.20 mm (over 80 years), with pupil sizes stabilizing after 60 years. The mesopic vertical pupil sizes when gazing far/near decreased from 6.35 +/- 0.11/6.27 +/- 0.14 mm (<20 years) to 3.42 +/- 0.30/3.21 +/- 0.28 mm (over 80 years). The pupil sizes decreased with age until 60 years and stabilized (1-way analysis of variance, P<.05). Fewer than 50% of subjects over 60 years of age had pupil sizes conducive to the near zone of refractive multifocal intraocular lenses. Photopic and scotopic pupil sizes decreased with age up to 60 years. The pupil was smaller when gazing at a near target than previously reported.

Relationship Between Antimicrobial Protein Levels in Whole Saliva and Periodontitis

Antimicrobial proteins are abundant in saliva. The purpose of this study was to determine and compare the amounts of two types of antibacterial protein, cystatin and lysozyme, in saliva between healthy persons and subjects with periodontitis. Forty subjects with periodontitis visiting Tokyo Dental College Chiba Hospital, Chiba, Japan, and 27 healthy persons were evaluated. Whole saliva was collected by requiring all subjects to expectorate into a sterile tube. Salivary levels of cystatin SA, cystatin C, and lysozyme were determined by enzyme-linked immunosorbent assay or immunoblot assay. Cystatin SA levels in saliva from the periodontally diseased group showed a mean value of 0.063 +/- 0.026 mg/ml, statistically lower than that in the healthy group (P <0.05). The average cystatin C level in the periodontally diseased group was 2.27 +/- 1.20 ng/ml, markedly lower than that in the healthy group (3.79 +/- 1.28 ng/ml; P <0.05). Average lysozyme levels in the periodontitis and healthy groups were 16.75 +/- 15.31 microg/ml and 30.03 +/- 15.03 microg/ml, respectively. The lysozyme level in the periodontitis group was significantly lower than in the healthy group (P <0.05). Specific monoclonal antibodies are useful for the detection of family 2 cystatins in saliva samples, and the amount of antibacterial protein in saliva offers a potential indicator of the risk for periodontitis.

Clinical Statistical Investigation of Cleft Lip and Palate Patients Aged Over 18 Years at Department of Orthodontics, Suidobashi Hospital, Tokyo Dental College

Since the fee for orthodontic treatment of malocclusion caused by cleft lip and palate (CLP) became covered by national health insurance in 1982, orthodontic treatment from school age has become the norm. However, in some CLP patients, orthodontic treatment is commenced in adulthood. A number of studies have reported on orthodontic treatment in adult CLP patients. The purpose of this study was to clarify the number and age of new patients, chief complaint, referral status, cleft type, malocclusion, history of orthodontic treatment, and acceptance and planning of orthodontic treatment. The study investigated new CLP patients aged over 18 years who visited the Department of Orthodontics, Suidobashi Hospital of Tokyo Dental College, between April 1, 2001 and March 31, 2006. During the investigation period mentioned above, 235 new CLP patients visited our department. Among them, 23 were aged over 18 years, accounting for 9.8% of the 235 CLP patients. In terms of chief complaint, occlusion-related complaints and occlusal dysfunction accompanying malocclusion were noted in 14 cases (61%). Eighteen patients were referrals. Unilateral CLP was the most prevalent cleft type. In terms of malocclusion type, reversed occlusion was noted in 13 cases (57%), accounting for over half of all cases. Patients with a previous history of orthodontic treatment accounted for half of all cases. Ten patients accepted orthodontic treatment. In terms of treatment plan, surgical orthodontic treatment was planned in 10 cases.