No abstract available.
Periodontal Ligament

The purpose of this study was to investigate the effects of load on root that was applied to edentulous area in three simulated situation, in each case the guiding planes of abutment were right vertical, 95 degrees, or 100 degrees to residual ridge. The 2-dimensional finite element method was used and the finite element model was prepared as follows. Right mandibular 1st and 2nd molar was lost and the 2nd premolar with distal rest was used as primary abutment which had three different degrees of guiding plane. Then 150N of compressive force was applied to central fossae of the 1st and 2nd molars and von Mises stress and displacement was measured. The results were as follows; 1. Irrespective of slopes of guiding planes, the stress was concentrated on mesial side of root apex and distal side of coronal portion of root, in particular on junction with distal alveolar bone. As slopes of guiding planes were increased, stress on root and compact bone surrounding abutment was increased but no considerable effect was seen on compact bone of residual ridge. 2. Distal side of coronal portion of root limited by periodontal ligament was displaced distally and mesial side of apical portion was mesially. With slope of guiding plane increasing, the pattern of displacement was similar with one another but the quantity was increased. 3. Both abutment &alveolar bone were displaced downward and root of abutment, especially distal side of coronal portion, was displaced severely. As the guiding plane was tiffed more mesially over 90degree, the degree of displacement was also increased.
Bicuspid ; Molar ; Periodontal Ligament

No abstract available.
Nicotine* ; Periodontal Ligament*

No abstract available.
Animals ; Periodontal Ligament* ; Phosphotransferases* ; Rats*

The purpose of this study was to analize the initial stress distribution around apex and the alveolar bone of the upper anterior teeth when applying intrusive force by the use of utility archwire, Burstone 3-piece intrusion archwire, and "J" hook headgear which is usually used in clinical practice. By the use of the polarization plate, initial stresses were analized when 80g and 150g force applied. The results were as follows. 1. With the utility archwire, moderate levels of stress were evenly distributed on the apical areas of the anterior teeth and concentrated on the apical areas of the first molars. 2. With the Burstone's 3-piece intrusion archwire, moderate levels of stress were evenly distributed on the apical areas of the anterior and posterior teeth. 3. With the "J" hook headgear, severe levels of stress were widely distributed on, the alveolar- bone and apical areas of the upper anterior teeth, and concentrated on the apical area between the central and the lateral incisors. Especially. weak levels of stress appeared along the periodontal ligament space of all teeth.
Incisor ; Molar ; Periodontal Ligament ; Tooth*

Periostin, a kind of matricellular protein highly expressed in periodontal ligament and periosteum, is an important regulator of the integrity of periodontal ligament and periodontitis processes. Periostin has been shown to play a positive role in the recovery of periodontitis. This paper reviews relevant literature about the role of periostin in periodontal tissue and periodontitis.
Humans ; Periodontal Ligament ; Periodontitis ; Periosteum

The propose of this study was to evaluate the effect of cellular activity of PDL cells dependent on intermittent and continuous compressive force by determining the alkaline phosphatase activity. An intermittent and continuous compressive forces were applied on PDL cells at the confluent stage. The alkaline phosphatase activity was measured on control and experimental groups every 24, 48, 72hours. The experimental group were consist of continous and intermittent compressive group which were compressed by 300g/cm2 of diaphragm pump. The intermittent compressive group was connected by timer which was worked on 10 minutes and off 10minutes. The results were as follow; 1. The alkaline phosphatase activity of intermittent compressive group was lower than control group at 24 hours(P<0.05). 2. The alkaline phosphatase activity between each groups showed no significant difference at 48hours. 3. The alkaline phosphatase activity of continuous compressive group was significantly higher than control group at 72 hours(P<0.01).
Alkaline Phosphatase* ; Diaphragm ; Periodontal Ligament*

The purpose of this study was to evaluate the effect of high glucose on prostaglandin E2 production in human gingival fibroblasts and periodontal ligament cells in vitro. In control group, the cells(5x10(4) cells/ml) were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum, 45mg/dl glucose. In experimental groups, glucose was added to the above culture condition at the final glucose concentrations of 100mg/dl(Test group 1), 200mg/dl (Test group 2) and 400mg/dl(Test group 3). Then each group was tested for the cell proliferation rate, protein levels, and prostaglandin E2 production at 1/2, 1, 2, 5 days. The results were as follows ; 1. As glucose concentration increased, cell proliferation rate decreased significantly at 1, 2, 5 days in human gingival fibroblasts and periodontal ligament cells(P<0.01). 2. In human gingival fibroblasts, test group 2 and 3 showed significantly decreased protein levels as compared to control group at 5 days(P<0.01). 3. In human periodontal ligament cells, as glucose concentration increased, protein levels decreased significantly at 2 days and 5 days(P<0.01). 4. Prostaglandin E2 production in human gingival fibroblasts and human periodontal ligament cells significantly increased as glucose concentration increased(P<0.01). The results at 5 days showed obvious difference as compared to those at 2 days. From the above results, high glucose appeared to affect cellular activities including cell proliferation rate, protein levels and enhance prostaglandin E2 production. It was assumed that prostaglandin E2 production by high glucose enhances inflammatory reaction and has a toxic effect on human gingival fibroblasts and human periodontal ligament cells. This study suggests that periodontal disease in diabetic patient is related to prostaglandin E2 production.
Cell Proliferation ; Dinoprostone* ; Fibroblasts* ; Glucose* ; Humans* ; Periodontal Diseases ; Periodontal Ligament*

This study was designed to examine the effect of polyP on the periodontal ligament fibroblasts. The cells were incubated for 24 and 48 hours with various concentrations (0.001%, 0.002%, 0.005%, 0.010%, 0.020%, 0.040%) of polyP. Cell activity, alkaline phosphatase activity, and protein synthesis activity of the cells were examined. The results were as follows: 1. Twenty four hours after incubation with polyP, the cell activity of the periodontal ligament fibroblasts was increased. Forty eight hours after polyP application, the activity of the cells was similar to that of control group. 2. Twenty four or forty eight hours after incubation with polyP, the alkaline phosphatase activity of the periodontal ligament fibroblasts was increased. 3. The protein synthesis of the periodontal ligament fibroblasts was not changed after polyP application. These results suggest that, polyP may increase the cell activity and alkaline phosphatase activity of periodotal ligament fibroblasts and polyP may not affect the protein synthesis of the cells.
Alkaline Phosphatase ; Fibroblasts ; Ligaments ; Periodontal Ligament* ; Polyps

No abstract available.
Cell Cycle* ; Humans* ; Periodontal Ligament* ; Stress, Mechanical*