Non-extraction treatment in Class III malocclusion by using improved superelastic NiTi wire / 대한치과교정학회지

Nonextraction camouflage treatment in mild Class III malocclusion is achieved by backward movement of the lower dentition and forward movement of the upper dentition. Many camouflage treatment modalities have been used for distal tipping and distal movement of mandibular posterior teeth. The amount of distal movement of mandibular dentition can be improved in cases of severe crowding, even without the patient's cooperation, by using miniscrews for anchorage. However, miniscrew insertion may be unsuccessful, and it may contact the adjacent root because of the distal movement of dentition. Distal tipping of mandibular dentition can be achieved using multiloop edgewise archwires and intermaxillary elastics. However, the complexity of this wire design causes discomfort to patients. Recently, a new treatment using improved superelastic NiTi wires (ISWs) and intermaxillary elastics has been introduced. ISWs can deliver orthodontic force more effectively, and their use with molar tip-back treatment has several advantages-this approach is effective, simple, and easy to use and reduces patient discomfort. The aim of this study was to report a case of camouflage treatment using ISW with tip-back and intermaxillary elastics for distal tipping of mandibular posterior dentition and to evaluate the effectiveness of this treatment in a clinical setting.

The effect of thickness and deflection of orthodontic thermoplastic materials on its mechanical properties / 대한치과교정학회지

OBJECTIVE: The purposes of this study were to evaluate the force and stress depending on the type, deflection and thickness of the materials and to evaluate the mechanical properties of thermoplastic materials after repeated loading. METHODS: Four types of thermoplastic products were tested. Force until the deflections of 2.0 mm and the stress when the materials were restoring to its resting position were evaluated. The mechanical properties of thermoplastic materials evaluated after 5 repeated loading cycles. RESULTS: The interaction was observed between the thickness and the deflection (p < 0.05) from the regression equation. Thickness and amount of deflection rather than products and materials showed the largest effect on force and stress. In all products, at least 159 gf of force was required for more than 1.0 mm deflection or when materials with 1.0 mm thickness were deflected. The stress recorded was more than 19 gf/mm2. During repeated loading, each group showed significant difference on the force and the stress p < 0.01), 10 - 17% reduction of force and 4 - 7% reduction of stress in average. CONCLUSIONS: Proper thickness of thermoplastic materials and deflection level of tooth movement should be decided for the physiologic tooth movement. Force decay after repeated loading should be considered for the efficient tooth movement.

Studies on the Cellular Transfer of Autoimmune Uveitis

After the immunization of pigmented guinea pigs with bovine rod outer segments in complete Freund's adjuvant, the regional lymph nodes were excised, teased and sedimented by centrifugation. These fresh lymphocytes were injected intravitreally (a single injection of 10 X 10 cells in 50 micro l) in 18 eyes. The involvement of the ciliary body and the choroid with polymorphonuclear leucoytes and later with round cells was noted in 16 eyes. Destructions of the visual cells of the retina were demonstrated in 8 eyes. When the fresh lymphocytes were injected subconjunctivally (50 X 10 cells in 30 micro l) four times. four of the 8 eyes showed slight infiltrations of the ciliary body and the choroid with round cells. No retinal lesion was found. Following repeated freezing and thawing of the lymphocytes. transfer experiments wereperformed with the nonviable cells and their extracts respectively. In 8 eyes injected intravitreally with nonviable cells. 2 eyes showed the infiltration of the uvea with round cells, whereas. of 6 eyes injected subconjunctivally, only one eye showed such changes. The extracts of lymphocytes were injected intravitreally in 8 eyes of which 5 eyes demon-strated moderate degree of infiltration of the uvea. Of 2 eyes injected subconjunctivally, 2 eyes. showed slight histological changes. As control experiments, lymphocytes taken from animals immunized. only with the adjuvant were treated as before and transferred to normal animals. Only one eye of 3 eyes received single intravitreal injection of fresh cells showed slight degree of infiltration of the uvea. Thus it can be concluded that the experimental autoimmune uveitis in guinea pigs could be transferred to normal animals by the transfer of non-viable lymphocytes and especially by their extracts.

A Case of Unsuspected Malignant Melanoma of the Choroid

The authors presented a case of malignant melanoma of the choroid which had been unsuspected clinically. The patient, 38-year-old female, came to Korea General Hospital on Dec. 5-1973 because of blind painful eye and white pupil in the left side. And she was told at local clinic that she had retinal detachment in that eye about 3 years ago. We thought of this case as secondary glaucoma due to swollen lens behind at first. Therefore cryoextraction of the lens was performed for relieving the ocular pain, on Dec. 5-1973. Increased I.O.P., however, had been persisted and ocular pain had not been improved until the patient entered this hospital again on Jan. 25-1974. Enucleation was performed and choroidal malignant melanoma (spindle type) was proven by histopathological study. The patient was instructive to us that we should always remind the possibilities of intraocular tumor behind the opaque media, in cases of unilateral glaucomatous blind eye with shallow anterior chamber.

Efects of Diathermy and Cryoapplication on the Seleral Shrinkage in Rabbits

In order to investigate the effects of diathermy and cryosurgery on the scleral shrinkage, nonperforating surface diathermy and cryocautery were applied in rabbits eyes. The premarked scleral segments were measured by corneal microscope with micrometer, and the resultant elevation of the intraocular pressures was pressures was measured by Schiotz tonometer. In the eyes treated by 10 diathermy in 5 X 3mm area, average 20.1% of scleral shrinkage was observed. There was no significant difference between shrinkages in the meridional and latitudinal directions. In the eyes treated by cryopencil no significant changes were found. Diathermy applications in 3 X 10mm area in the sclera induced 36.9% increase in the intraocular pressure which lasted about 9 minutes. On the other hand, cryoapplication did not produce such an elevation in ocular tension.

A Case of Glaucomatocyclitic Crises

A case, 25-year-old male student who is thought to have been suffered from glaucomatocyclitic crises in the left eye, is presented. Authors have followed this patient for about one and a half years. During the time, 10 times of recurrent unilateral attacks of ocular hypertension have been noted with assoicated mild iridocyclitis. An attempt was made to evaluate the clinical pictures and review the literatures.

The Effect of Normal Ocular Tension on Vitreous Loss in Cataract Operation

From 39 eyes of 31 cases which received the cataract operation performed under the surface anesthesia by 2 specialists, 2 senior, 1 third and 1 first year residents at Red cross Society, the following results were obtained. 1. The maximal value of intraocular pressure was 19.0mmHg, minimal value, 11.5mmHg and the average, 14.9mmHg just before the cataract operation. 2. The rupture of the capsule was 21.4% and the loss of vitreous body, 7.1% in intraocular lens extrations. 3. The degree of anteior projetion of the eyes had not direct relationship with the intracapsular lens extraction. 4. All patients who received the cataract operation were required sufficient akinesia sedation. 5. Within normal intraocular pressure, the intraocular pressure didn't seem to have any effect to the loss of vitreous body.