Nichidai koku kagaku = Nihon University journal of oral science最新文献

The following findings have been obtained as a result of investigating the patients with TM disorder before and after correction of the mandibular repositioning as it was considered that, if the sound transmitting middle ear hearing system which undergoes change along with the morbidity in progress shows reversible changing aspect in response to the ebb and flow of the morbidity, it would serve as quantitative diagnostic criteria regarding the repositioning by means of bite-plane therapy. Changes were observed between before and after repositioning in 3 item measurement. The values of static compliance, impedance and pressure of middle ear were reduced to the level of those in healthy subjects. Consequently, the following conclusions were reached: Impedance audiometry serves as quantitative judging criteria regarding the repositioning of the mandible by means of bite-plane therapy.

Since the dental environment at a living place could potentially become a factor causing a need for dental care, all 33 elderly homes (27 of which responded to the survey) in Tokyo were investigated for the purpose of identifying the present status of dental care service and the problems existing at these homes. The following are the obtained conclusions. 1. The rate of homes with dental care facilities is as low as 19.2%, and cooperation by dental care institutions, including house calls, is ensured only at the low rate of 11.1%. As a result, usually patients visit the dental institutions. 2. The involvement of the dental staff, including part-time, was 44.4%, less than half of the homes surveyed. The homes wishing to employ or receive service from dental staff accounted for 76.9%. The homes also expected them to be engaged in the activities of overall oral hygiene, including not only dental treatment, but also participation in the planning of oral hygienic management. However, 23.1% of the respondents did not wish to employ any dental staff or receive any such service. 3. Specific programs for the guidance and management of oral hygiene were not observed. Homes that conducted dental examination periodically and those that carried out activities related to oral hygiene during Dental Health Week were also lacking. In addition, the homes which had assigned personnel responsibility for oral hygiene represented only 12.0%.(ABSTRACT TRUNCATED AT 250 WORDS)

Of the total of 1,371,122 out patients who received the clinical examination in the department of Clinical Pathology. Dental Hospital, Nihon University School of Dentistry at Mastudo for 12 years during April 1, 1977 to March 31, 1989, their clinical examination data were gathered and evaluated. The following results were obtained. 1) The average number of patients who received examination was 1,582.2 per year. 2) The ratio of male to female of the examined patients was 1 to 1.04 respectively. 3) The largest number of patients examined was in their age of 40's in both sexes. 4) Among the various clinical departments, oral surgery department most frequently requested clinical examination followed by head and neck surgery, pedodontics conservative dentistry and anesthesiology departments. 5) Among 7 major clinical examination including general, hematological, biochemical, serological, bacteriological, physiological, and pathological examinations, biochemical evaluation was most frequently requested. In average, 30.5 different examinations were performed per patient. 6) Recently, among pathological and serological examinations, the request of HBs antigen and syphilis examinations were increased.

The purpose of the present study is to clarify the influence of microflora in plaque of the brackets edge by direct bonding system and the cause of caries that is induced around the bracket during orthodontic treatment. The subjects were selected from the patients undergoing direct bonded orthodontic treatment and from the non-orthodontic patients. They were divided into four groups: those having no orthodontic treatment (control group), those having no caries around the bracket (group A) and those having caries around the bracket (groups B and C). Sample plaques were collected from the initial tooth surface with control group, from the tooth surface around the bracket with group A, from the carious cavity around the bracket with group B and from the non-carious tooth surface around the bracket with group C. The isolation rates of microflora in dental plaque of the four groups were compared, and the following conclusions were obtained. 1. Group A had almost same level with control group as to the proportion of each bacterium examined by shape and gram stain of microbiota. Group B had higher level of gram positive cocci than the other groups. 2. Group A and control group had no difference as to the isolation rates of genera Streptococcus, Actinomyces and Lactobacillus. 3. Group A had low level of S. mutans, was the same as control group. 4. The isolation rate of each genus: 1) The isolation rate of genus Streptococcus was almost same in groups A, C and control group. Group B had higher than the other groups. 2) The isolation rate of genus Actinomyces was the highest in all groups. 3) The isolation rate of genus Lactobacillus was exceedingly low. 4) Groups B and C had significantly higher level of S. mutans group than group A and control group. Group B had significantly lower level of S. mitior than group A and control group. 5. All four groups showed high level of biotype I, and biotype IV was observed in groups B and C. Biotype I was identified as S. mutans serotype c, biotype IV was observed as S. sobrinus serotype d.

Authors have developed a mandibular retraction system in a rat that was constructed by arms having a metal mesh, an incisor metal cap, a pair of closed coil springs and a soft plastic collar. The merit of this system is that the anchor is very stable because it is made on the parietal bones, and the direction and load of the traction are invariable regardless of head position of the rat compared to the previous methods in which the anchor was made on the neck collar of a rat. Seventy of 8-week-old male Wistar rats were divided into five groups that were intact, collar, sham operation, straight-pull and high-pull. The anchor was implanted with a metal mesh into the subperiosteal space of the parietal bones just in front of the lambda suture of a rat. The coil spring attached on the sliding hook on the arm was connected with a hook soldered with an incisor metal cap. Therefore, the mandible was retracted in the TMJ direction (straight-pull) and some were 20 degrees upper than TMJ (high-pull) for 15 days at a tension of 10 g. All operations except for traction by the coil springs were performed on a rat in the sham operation group. Only the plastic collar was set on the neck in the collar group. Mandibular retraction for 15 days showed significant inhibition of the sagittal growth of the mandible in both high- and straight-pull groups. No inhibition of sagittal cranial growth was observed according to morphometrical and microscopical investigations.(ABSTRACT TRUNCATED AT 250 WORDS)

An angular measurement was conducted on 12 cases with cross bite and 18 cases without among the patients who underwent surgical orthodontic treatment for mandibular protrusions (true Class III) and the following results were obtained. 1) An angle measurement for each plane against X axis is helpful for a judgement of facial symmetry. 2) The distortion of each portion (each plane) can be judged from the angular difference of each plane. 3) The angle measurement seems to be useful enough in planning for paper surgery.

We investigated the effectiveness of commercially available silane coupling agents on the adhesion between the composite resin and the porcelain. As silane coupling agents, we used Cosmotech primer. Clearfil porcelain bond. Porcelain liner M, and Scotchprime. As porcelain, we used Cosmotech porcelain DA2 which was etched either with hydrofluoric acid or with phosphoric acid gel. The tensile bond strengths between composite resin and the porcelain treated with silane coupling agents were measured after one day immersion in 37 degrees C water. Among the silane coupling agents, Clearfil porcelain bond gave the highest bond strength of about 175 kgf/cm2. When any of these silane coupling agents were used, the bond strengths were increased more by hydrofluoric acid etching than by phosphoric acid etching. Especially in the case of Scotchprime treatment, hydrofluoric acid etching was remarkably effective on the increase in the bond strengths. The value in hydrofluoric acid etching was 3 times higher than that in phosphoric acid etching. From SEM observation, hydrofluoric acid etching gave greater roughness to the porcelain surface, which resulted in greater mechanical interlocking of the resin. In the case of Cosmotech primer treatment, the combination with GC bonding agent did not increase the bond strengths, while combination with Clearfil new bond did. The phosphoric acid ester monomer in Clearfil new bond, which is known as strong acid, was supposed to catalyze the activation of silane coupling agent.

Tympanometric measurement has been made on centric relation and working side and non-working side in 19 healthy subjects (12 males and 7 females aged 23-27) and the following conclusions have been obtained: 1. The Tympanogram in the healthy subjects showed a symmetrical pattern, being of type A bilaterally, in all the cases, and no lateral or sexual difference was seen any item of measurement. 2. S. C. value increased in order of centric relation, working side and non-working side, but decreased in IMP., PRS. and EAC.. 3. Significant differences were observed in the items of measurement regarding S. C. and IMP. all between centic relation and working side, centric relation and non-working side, working side and non-working side. These findings show a correlation between the function of middle ear and the horizontal mandibular position. Therefore these findings suggest the possibility of tympanometric measurement becoming one of the parameters as the method for objective evaluation of the mandibular position as the change in the function of the middle ear.

Hydroxyapatite (HAP) is currently utilized as biomaterials for implantation or reconstruction of bone defect in dentistry. In order to obtain better physical properties and biocompatibility, we have developed cylindrical sintered porous HAP which has longitudinal internal tubules. We measured compressive strength and specific surface area of cylindrical HAP. In the results, compressive strength was more 300MPa on average and specific surface area was 1.7-2.4 folds as HAP ceramics commercially available. This result indicates new bone formation. Cylindrical HAP used was subsequently applied to lower premolars and molars of male beagle dogs (1.5 years). We have implanted cylindrical HAP to bone defect of postextraction of tooth followed to sacrifice six months after. Specimens of bone block were stained with Villanueva bone stain and observed with fluorescence microscope and scanning electron microscope. New tissue formation was observed invading into tubules of 27 microns diameter of cylindrical HAP particles. This new tissue was confirmed to be bone tissue because the proportion of Ca to P was 1.616 obtained by energy dispersive X-ray analyzer.

We divided lymph nodes into three groups, those that are normal, those with lymphadenitis, and those that are metastatic. We analyzed these groups based on their ultrasonographic images by measuring maximum cross-section, L/T ratio, coutour, internal echo images, and posterior echo images, and examined the results statistically. In this study, especially for images relevant to internal echoes, the sound wave reflected from the interior of the lymph nodes was taken as aggregate of bright spots, which were analyzed in terms of the following aspects: texture or size, distribution pattern, and brightness. The results are as follows. (1) The size of the lymph nodes is 7.1 +/- 1.7 mm (mean +/- S.D.) for normal, 10.6 +/- 3.8 mm for lymphadenitis, and 13.1 +/- 7.3 mm for metastatic. (2) The L/T ratio is 0.55 +/- 0.16 for normal, 0.64 +/- 0.21 for lymphadenitis, and 0.83 +/- 0.15 for metastatic. (3) The increment of the lymph node size and the variation in L/T ratio are plotted in the disperation diagram. It was concluded that differential diagnosis would be difficult only based on the size and L/T ratio of the lymph nodes under study. (4) The contour appears indistinct in normal lymph nodes, especially in their lateral aspect, while it is distinct around the whole circumference in lymph nodes with inflammation or metastatic cancer. (5) From the analysis based on texture, distribution, and brightness of the echo images of the interior of lymph nodes, it was concluded that in metastatic lymph nodes, aggregated echoes are distributed unevenly, and their brightness is similar to that of adjacent tissues. 6. Posterior echo images were unique findings that showed acute lymphadenitis. Those analytical results based on the three types of findings were rated and submitted to T-tests, which showed that there is a significant difference at a level of 5% among normal lymph nodes, those with inflammatory changes, and those with metastases.(ABSTRACT TRUNCATED AT 250 WORDS)