Histologic effects of intentional-socket-assisted orthodontic movement in rabbits / 대한치과교정학회지

OBJECTIVE: This study aimed to evaluate the effect of an intentionally created socket on bone remodeling with orthodontic tooth movement in rabbits. METHODS: Eighteen male rabbits weighing 3.8 - 4.25 kg were used. An 8-mm deep and 2-mm wide socket was drilled in the bone 1 mm mesial to the right mandibular first premolar. The left first premolar was extracted to serve as an extraction socket. A traction force of 100 cN was applied to the right first premolar and left second premolar. Sections were obtained at the middle third of the moving tooth for both the drilled and extraction sockets and evaluated with hematoxylin and eosin staining and immunohistochemical analyses. The amount of tooth movement and tartrate-resistant acid phosphatase (TRAP)-positive cell count were compared between the 2 groups using the Mann-Whitney U test. RESULTS: At week 2, the distance of tooth movement was significantly higher in the intentional socket group (p < 0.05) than in the extraction socket group. The number of TRAP-positive cells decreased in week 2 but increased in week 3 (p < 0.05). However, there were no significant differences between the groups. Furthermore, results of transforming growth factor (TGF)-beta staining revealed no significant differences. CONCLUSIONS: The intentional socket group showed greater distance of tooth movement than did the extraction socket group at week 2. Osteoclast counts and results of immunohistochemical analyses suggested elevated bone remodeling in both the groups. Thus, osteotomy may be an effective modality for enhancing tooth movement in orthodontic treatment.

Vestibular Evoked Myogenic Potential Generated by 500 Hz Tone Burst in Unilateral Peripheral Vestibulopathy

BACKGROUND AND OBJECTIVES:Vestibular evoked myogenic potential (VEMP) has become a valuable diagnostic tool evaluating the integrity of sacculocollic reflex and has been done using click sound in most previous clinical trials. This study aims to investigate VEMP responses generated by 500 Hz tone burst in unilateral peripheral vestibulopathy and compare the response with caloric test and subjective visual vertical (SVV). MATERIALS AND METHOD:Clinical records of 37 patients (18 men and 19 women, aged 14-80 years) with unilateral peripheral vestibulopathy were reviewed. Diagnoses were Meniere's disease (n=13), vestibular schwannoma (n=4) and acute peripheral unilateral vestibulopathy (n=20). They underwent 500Hz tone burst VEMP, caloric test and SVV test. Thirteen healthy volunteers (26 ears, 8 men and 5 women, 25~41 years) with normal hearing were enrolled as control group. RESULTS:VEMP response was present in every control ear using 500 Hz tone burst stimuli. In Meniere's disease, VEMPs were positive in 57% (4/7) of patients with abnormal caloric response group and 83% (5/6) with normal caloric response. In acute peripheral vestibulopathy, VEMPs were positive in 47% (9/19) of patients with abnormal caloric response, 0% (0/1) with normal caloric response. The average of CP (canal paresis) in positive VEMP group was 62.4% and that in negative VEMP group was 48.2% (P>0.05). CONCLUSION:Reliable and reproducible test results can be obtained using 500 Hz tone burst stimuli. VEMP results were not in concordance with other vestibular tests, which reflects the dynamic process of dizziness and variable extent of pathology in each case.

Treatment with Botulinum Toxin A in Continuous Facial and Neck Myokymia: A case report

Myokymia is a clinical phenomenon characterized by undulating, vermicular, rippling and wavelike movements spreading across the muscle surface. Facial myokymia is an unusual complication of brainstem hemorrhage. It tends to occur in brainstem tumor or multiple sclerosis. We report a 51-year-old man with continuous facial and neck myokymia after brainstem hemorrhage, who revealed focal myokymic discharges in face, neck and pharyngolaryngeal muscles in-nervated by cranial nerve V, VII, X, and XI. After injection of 20-80 units of Botulinum toxin type A (Dysport ) to the left orbicularis oris, mentalis, mylohyoid and posterior belly of digastric muscles, amplitude of continuous myokymic discharges was markedly reduced. We recommend Botulinum toxin injection as a very effective therapeutic method in managing focal movement disorders.

Working Posture and Muscle Tension according to Screen Position during VDT Operation

OBJECTIVE: To evaluate working condition in way of measuring working posture and muscle tension using the desktop personal computer and notebook personal computer having different screen height. METHOD: Seventeen healthy men performed wordprocessing task in three workstation: desktop PC on the conventional computer table (DPC (on)); desktop PC under the 'inside' type computer table (DPC (under)); notebook PC on the table (NPC). The viewing distance and angle, head and neck angle, thoracic bending and trunk inclination were measured. Muscle tension of right posterior neck muscle, upper trapezius, sternocleidomastoid (SCM), and upper back muscle was also measured by integrated electromyogram (IEMG). RESULTS: 1) The viewing distance was the longest in DPC (under). 2) The lower the screen height, the more downward viewing angle and more flexed position in upper neck. 3) The posterior neck muscle tension was the lowest in DPC (on). 4) Stooped position was most frequently seen in NPC and the highest tension of posterior neck muscle and upper back muscle was shown in NPC. 5) In relation between postural analysis and muscle tension, muscle tension decreased with increasing backward reclining position, and the neck and thorax became more erect with increasing in viewing distance. CONCLUSION: These results suggest that the stooped posture was worst and most frequently seen in NPC. If neck flexion is avoided, DPC (under) position could lessen the visual and musculoskeletal problem. More Ergonomical study would be needed about working posture using computer.

Relationship between Nocturnal Polyuria and Antidiuretic Hormone in Chronic Spinal Cord Injury

OBJECTIVE: To delineate the role of antidiuretic hormone (ADH) in relation to nocturnal polyuria, and to identify the factors influencing on the diurnal antidiuretic hormone level. METHOD: The ADH was measured by radioimmuoassay at daytime (2:00 PM) and at nighttime (2:00 AM) with nocturnal polyuria group (11) and without nocturnal polyuria group (8). Urine volume, serum osmolarity, urine osmolarity, and blood pressure were also measured at the same time. RESULTS: 1) The ADH at 2:00 AM did not increase in nocturnal polyuria group, although it increased in no-symptom group. 2) There was a statistically significant correlation between wheelchair ambulation time and daytime ADH level. 3) The difference of ADH level between daytime and nighttime showed decrease in orthostatic hypotension group. CONCLUSION: There was relationship between nocturnal polyuria and diurnal variation of ADH level. The ADH concentration seems to be influenced by the postural factors and sympathetic factors.