Removal torque and bone formation of orthodontic miniscrew implant / 대한치과보철학회지

STATEMENT OF PROBLEM: An orthodontic miniscrew implant has been used as a skeletal anchorage for orthodontic treatment. However, any relation among the influence of the cortical bone, morphologic differences of orthodontic miniscrew implants and new bone formation hasn't been made clear yet. PURPOSE: The purpose of this study was to evaluate whether the orthodontic miniscrew implant could work as an intraoral skeletal anchorage immediately and stably for orthodontic treatment after insertion of it. MATERIAL AND METHODS: Two types of orthodontic miniscrew implants were used in this experiment; tapered type and straight type. One hundred and sixty eight orthodontic miniscrew implants were inserted into the tibiae of 21 rabbits and sacrificed on 3, 7, 11, 14, 21 and 28days later after insertion of them to study removal torque values and histologic and histomorphometric analyses. RESULTS: The results were as follows. 1. The removal torque values of the tapered type were higher than those of the straight type in all groups(p<0.05). 2. There wasn't any distinguishing differences between the tapered type and the straight type about the new bone formation percentage. 3. The removal torque values for both the tapered type and the straight type were gradually decreased at early stages of the test but started to increase at the 7 days group of the straight type and the 11 days group of the tapered type. 4. New bone formation percentage was increased gradually for both the tapered and the straight types as time passed(p<0.05). 5. It was found that the tapered type showed lower values in the cortical bone about both the maximum equilibratory stress distribution and the maximum principal stress distribution than the straight type in linear finite elements analysis. CONCLUSION: According to the research, the removal torque values were decreased at 7 days group of the tapered type and 11 days group of the straight type after the insertion of the orthodontic miniscrew implants in tibiae of rabbits. Considering the human bone activity, it is better to apply the orthodontic force 3.4 weeks later than to apply it immediately after the insertion of orthodontic miniscrew implants. Considering that general orthodontic force is about 250.500 grams, the tapered type can be worked as a stable skeletal anchorage in an orthodontic treatment even if the orthodontic force is applied on it immediately after the insertion of it.

Mandibular clinical arch forms in Koreans with normal occlusions / 대한치과교정학회지

The purpose of this study was to clarify morphologic characteristics between mandibular clinical arch forms in Koreans with normal occlusions. The study included data from 102 Koreans. The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. The dental arches were classified into ovoid, square and tapered forms. The frequency distributions of the three mandibular arch form classifications were determined and compared between male and female subjects. No significant differences in arch form size were found between the sexes. However, there were a few differences in molar width. It was useful to classify mandibular clinical arch forms present in normal occlusion samples into ovoid, square and tapered categories. The frequency of the ovoid form was the highest, and that of the square form was the second highest. The tapered arch form was found in less than 10 percent of subjects. No significant differences in their frequency distributions and dimensions were shown between males and females.

Temporal Lobe Volume in Geriatric Depressive Patients: A Magnetic Resonance Imaging Study

OBJECTIVE: The purpose of this study was to measure and compare temporal lobe volumes of geriatric depressive patients and normal controls. Temporal lobe volume was measured with computerized volumetric technique using brain MRI films. METHOD: We studied 15 patients of 50 years or older with major depressive disorder (MDD) and 14 normal control subjects, measured temporal lobe volumes and cerebral volumes of both groups using semi-automated imaging analysis program from brain MRI films. A statistical analysis was done to compare right and left volumes in both groups and to compare right and left volumes in each group. The comparison of right and left volumes between early-onset MDD group and late-onset one and correlation with duration of illness of MDD group were taken too. RESULTS: There was no difference in right and left temporal volumes between MDD group and normal control (right p=.760, left p=.219) but there was statistically significant difference between right and left volume in normal controls who have larger right temporal lobe volume than left temporal lobe volume (p=.002) compared to MDD patients who have no difference between right and left temporal lobe volume (p=.644). In MDD patients, there were no difference between early-onset MDD group and late-onset one and no correlation of volume with duration of illness. CONCLUSION: This study aiming at identifying the structural change of brain in geriatric depressive patients did not reveal any difference of temporal lobe volume between MDD patients and normal controls, and between right and left temporal lobe in geriatric MDD patients. The loss of laterality in patients was partially identical with the previous results of other studies, so it needs further following studies which have larger size of subjcets with various implicated variables and more fine brain structures.

Sleep Habits and Insomnia-associated Factors in the Urban Elderly: Demographic, Health and Psychobehavioral Correlates / 신경정신의학

OBJECTIVES: The purpose of this study is to analyze sleep habit and investigate the association between insomnia and demographic, health and psycho-behavioral symptomatology in Korean urban elderly. METHOD: A total of 723 community residents aged 65 years or older were surveyed by two stage, random cluster sampling method. The response rate was 76.2%. Interviewers performed door to door visits and administered a questionnaire about sleep, past medical history, and several scales as the Psychogeriatric Assessment Scale (PAS), the short form Quality of Life Scale (SF-36) and etc. RESULTS: The mean scores are as follows: retiring time was ten-sixteen p.m., wake-up time was five twenty two a.m., duration of sleep was seven hours and six minutes. Among the elderly, 11.6% and 14.8% of the subjects reported chronic and intermittent difficulty in sleeping, respectively. The patients with back pain and history of stroke complained of more insomnia symptoms in univariate analysis. In ANCOVA analysis, insomnia symptoms were associated with an old age, depressive symptoms in male. Bodily pain and history of dermatologic disease were additional risk factors in female. CONCLUSIONS: The data suggest insomnia is one of most common health problems among elderly Koreans living in the community. Strong positive relationship between depressive symptoms and insomnia were found. Further research is needed to explore the causal relationship between insomnia and risk factors.

The Effect of Zolpidem on the Psychomotor Performance in Healthy Volunteers / 신경정신의학

OBJECTIVES: Zolpidem is known to have fewer cognitive side effects than older hypnotics. To confirm this objectively, we compared the effects of zolpidem on the psychomotor performance with those of placebo in 10 healthy volunteers. METHOD: Zolpidem and placebo were administered orally in a double-blind, two-way, single dose, cross-over design. Assessments of psychomotor performances were carried out before (1 hour) and 1.5 and 6 hours after the administration of single dose of zolpidem (10mg) or placebo. Each treatment day was separated by 1 week of washout period. The psychomotor performances were measured using Vienna Determination Unit, Vienna Reaction Unit, Vienna Signal Detection, Grooved Pegboard Test and Finger Tapping Test. The data were analyzed using two-way, repeated measures ANOVA on a crossover model. RESULTS: The results showed that 1.5 hours after the administration, zolpidem 10mg produced markedly impaired psychomotor performance but 6 hours after, produced no significant psychomotor performance decrements on most of the psychomotor tests. CONCLUSION: This study confirmed previous findings that zolpidem is generally devoid of adverse side effects on psychomotor performance at the next day after administration.