Gifu Shika Gakkai zasshi = The Journal of Gifu Dental Society最新文献

On a 23-year-old woman who came to our hospital for anterior teeth crowding accompanied with severe periodontal tissue disease, from which she wanted to be recovered within 2 years, as cc, treatment of the paradental disease was performed for a year, then 55/44 were extracted and length discrepancy was improved in a year according to the edgewise method. Both these treatments removed all of the inflamatory symptoms such as local bleeding, drainage, etc, which had been noted before treatment, leading to normally functional occlusion. X-ray didn't reveale alveolar crest and or root resorption following the orthdontic tooth movement but, there is rather a considerable elevation of the alveolar line of the 2 1 1 2 region.

We studied the possibility of estimating the root surface area from measurements of various points on extracted teeth using multiple regression analysis, and found that this method might be applied clinically.

In this study, apatite coated subperiosteal and endosseous implants were prepared by the build-up technique, that is, dental alloy was cast in the required shape, and a covering of glass was fused onto it. Then hydroxyapatite powder was coated on the surface of the glass coat and hydrostatically pressed to form a compact layer which was then heated. These implant materials were tested by animal experiment to evaluate the applicability for clinical use. The results suggested that endosseous subperiosteal implants are available for maxillary molar parts.

A cephalometric study of reversed occlusion in the rest position was performed. Materials consisted of cephalograms which were taken from 20 Japanese with reversed occlusion Study was made of the 2 dimensional changes in cephalograms before and after treatment, in order to determine its value for the estimation of the mandibular position after treatment of reversed occlusion, for therapeutic purposes, and also its value as a rotational element in preparation of Ricketts' V.T.O. Superimposed cephalometric tracings were made in the pretreatment and posttreatment rest positions. Using these, the method was evaluated for current use in analysis. The superimposition of tracings enabled estimation of the mandibular position and habitual position with an accuracy of 80% (16/20 cases). Coincidence of posttreatment mandibular position and pretreatment rest position was obtained in all adult cases. Utilization of the rest position for preparation of Ricketts' V.T.O. made it possible to estimate the growth direction and the mandibular position with an accuracy of 65%. Superimposition of pretreatment rest position and posttreatment habitual occlusal position led to coincidence of V.T.O. 84% of the time. Case analysis by means of Rákosi's functional analysis was effective for the determination of the relative therapeutic difficulty and the therapeutic approach. Utilization of the rest position, in addition to Kim's ODI and APDI values proved to be capable of determining the exact therapeutic plan at a probability of 70%. The above results revealed that the preoperative rest position was effective, not only for functional analysis, but also for the estimation of the therapeutic goal for adult cases and of the first stages-completion (at the overjet correction) for young cases.

The wear facets produced 10 years ago were compared with the present ones in a 35-year old patient with bruxism. The electromyographic data of 10 years ago were also compared with the current data. Current mandibular kinesiograph data were also measured. The total area of the present wear facets was increased approximately 2.3 times those of 10 years ago in the upper teeth, and approximately 2 times in the lower teeth. However, the number of current wear facets of the upper and lower teeth was reduced, compared to that of 10 years ago. The Gothic arch tracing revealed a difference of about 1 mm between the centric occlusion and the centric relation. The patient had a unilateral balanced occlusion and a grinder-type chewing pattern. The free-way space, was in a normal range, approximately 2 mm. The raw electromyographs during sponge chewing 10 years ago differed from the present findings, although the chewing rhythm was the same.

In this study, in order to determine a method for obtaining a good reaction, the reactive products of 3.8% Ag (NH3)2F, using formalin as a reducing agent, were studied. Saforide RC was used as the 3.8% Ag (NH3)2F solution and 10% neutral formalinsolution was used as a reducing agent. The silver mirror test and reaction products on the root canal wall were investigated under the scanning electron microscope, along with observation of dye penetration using a stereoscopic microscope. Reaction of periapical tissue to the materials was studied histologically in dogs. In the natural reduction group, less amounts of reactive products were seen, and sealing of the dentinal tubules of the root canal wall was inadequate. In the formalin reduction group, large amounts of reactive products were found, and the dentinal tubules of the root canal wall were sealed. CaF2, Ag3PO4, Ag2O and Ag were identified as reactive products. In the natural production groups, obstruction was present but incomplete. In Formalin groups, dye osmosis obstruction was recognized. No harmful action of the solution on the surrounding tissue of the dog's tooth was recognized.

A quantitative analysis of EMG activity in temporal and masseter muscle and of mandibular movement was performed in prognathia (n = 20) and normal (n = 30) occlusion. EMG recordings were analyzed during rest position, maximal clenching and maximal clenching with a cotton-roll. Mandibular movement was examined for path of closure, amount of freeway, maximal velocity of jaw opening and closing, condylar test and amount of maximal vertical jaw opening. The results of the investigation revealed the following. Normal occlusion and prognathia were classified into two groups by path of closure. One group was going toward the upper front and another toward the upper back. The former was indicated in 77% of normal occlusion and 65% of prognathia cases examined. Amount of freeway space was the same in both groups. Maximal velocity of jaw was significantly (p less than 0.05) faster for prognethia than for normal occlusion. Condylar test was significantly (p less than 0.05) greater for prognathia than for normal occlusion. Temporal muscle activity was greater for normal occlusion than for prognathia. During maximal clenching, temporal muscle activity was greater than masseter activity in the normal occlusion. A tendency toward negative correlation was found between temporal muscle activity during maximal clenching and the mandibular plane angle, facial height and gonial angle. The same tendency was found between masseter muscle activity and the mandibular plane angle, facial height, ramus-height and gonial angle. These results prove that it is important to examine muscle activity and mandibular movement to make treatment planning.

This study examined the characteristics of masticatory motion path using multivariate analysis. Principal component analysis was selected as the method and various important results were revealed as follows; Approximately 70% of the information describing gum chewing motion was explained by three principal components. From factor loading, the first principal component explains back and forth movement from the end of the opening phase to the closed position, the second principal component explains left to right movement at the onset of the mouth opening phase, and the third principal component explains left and right movement at about the position of maximum opening. Using scatter diagrams combining the first and second principal components, as well as the first and third principal components, we were able to recognize delicate differents among the subjects, but to the different strokes of any subject, characteristic patterns were emerged.

The purpose of this investigation was to understand how the mandibular movement and myofunction in reversed occlusion, approach to normal occlusion after the correction of over jet. The experiment was carried out in 30 normal and 26 reversed occlusion school children patients who were classified into 3 groups by morphological analysis. A K6 diagnostic system was used. It recorded muscle activity of maximum clenching, free way space, path of closure, and the maximum velocity of opening and closing mandibular. And recorded a condylar test at the same time. Reversed occlusion classified 3 groups: upper and lower incisor had improper inclinations (D group, 19%), construction bite possible but recognized back and forth discrepancy between maxilla and mandibular (FS group, 50%), discrepancy larger than FS group and construction bite not possible (S group, 31%). Toward upper forth group indicated 77% and toward upper back group indicated 23% in normal occlusion. As for reversed occlusion the former indicated 92% and the latter indicated 8%. Differences in connection with orthodontic appliance and period of treatment were not so large. Back and forth mandibular movement, as measured by a condylar test, was greater for reversed occlusion than for normal occlusion, but this value tended to decrease after orthodontic treatment. In reversed occlusion, maximum opening, free way space, maximum velocity of opening and closing and muscle activity of rest position didn't show significant difference (p less than 0.05) among each group before and after the correction of over jet. Temporalis and masseter activity of maximum clenching, except temporalis among the D group, approached the values for normal occlusion. In the S group, muscle activity of maximum clenching with a cotton-roll, was lower before treatment, but approached to data in normal occlusion. These results prove that improvement of over jet in reversed occlusion, by ordinary orthodontal diagnosis and treatment plan, quasi-normalizes mandibular movement and muscle activity in reversed occlusion.