Background:Noncarious cervical lesions (NCCLs) are rarely described in the periodontal literature, perhaps because no direct link between NCCLs and periodontal lesions has been demonstrated.Aim:The aim of this study is to determine the stress and displacement produced in the tooth at different bone levels under different occlusal load using finite element model (FEM) study.Materials and Methods:Four FEMs of maxillary incisor were designed consisting of the tooth, pulp, periodontal ligament, and alveolar bone at the various level of bone height (25%, 50%, and 75%). Different occlusal load (5 kg, 15 kg, 24 kg, and 29 kg) at an angle of 50° to the long axis of the tooth was applied on the palatal surface at the level of middle third of the crown. All the models were assumed to be isotropic, linear and elastic, and the analysis was performed on a Pentium IV processor computer using the ANSYS software.Results:The maximum stress in the tooth was seen in the cervical region and to a greater extent at the apex for all models. The maximum tooth displacement for all the occlusal loads applied in this study was at the incisal edge with the minimum tooth displacement at the cervical third of the root which shifted apically with the reduction of alveolar bone support.Conclusion:The cumulative effect of increased stress and displacement at the cervical region of the tooth would result in abfraction as the age advances along with other wasting diseases.
BACKGROUND: Intra Ocular Pressure (IOP) can be altered by changing body position. Very few studies are available in the Indian subjects. AIM: To study the effect of changes in the body position from upright posture to supine to head down tilt of-60 0. MATERIALS AND METHODS: The study group consisted of 60 subjects, 35 boys and 25 girls in the age group of 18 to 24 years, with no ocular pathology were chosen. Independent measurements of the IOP of each eye were obtained. Keelar Pulsair air impulse tonometer was used in all the subjects for IOP measurement. IOP was measured in the department of Ophthalmology, Teaching Hospital between 10AM to 12 Noon. STATISTICAL ANALYSIS: were done using Student's paired 't' test. RESULTS: The change of IOP (Increased) induced by the change of position between the means of IOP's for the sitting and supine positions was 2.789±1.03 mm Hg of all subjects, 2.825±0.226 mm Hg in males and 2.739±0.089 mm Hg in females and between the supine and inclined-60⁰ position was 4.971±0.914 mm Hg of all subjects, 4.703±0.816mm Hg in males and 5.346±1.098 mm Hg in females. CONCLUSION: It is apparent that, the IOP is significantly higher in the supine than in the sitting and in the inclined than in the supine positions. The difference was statistically significant (P<0.001).
BACKGROUND: Intra Ocular Pressure (IOP) changes following dynamic (Isotonic or Isokinetic) and static (Isometric) exercise. AIM: To study the effect of dynamic and static exercises on IOP and blood pressure in the same subject following each type of exercise and to correlate the changes in BP to the changes in the IOP. MATERIALS AND METHODS: The study group consisted of 55 volunteers, visually normal as subjects, 30 boys and 25 girls in the age group of 18 to 20 years. Independent measurements of the IOP of each eye were obtained and BP was also measured in the resting state. Keelar Pulsair air impulse tonometer was used in all the subjects for IOP measurement. IOP was measured in the department of Ophthalmology, Teaching Hospital between 08AM to 10 AM on two consecutive mornings in a randomized manner. The subject undertook static exercise using the hand grip dynamometer and towards the end of the test, IOP and BP were measured. The next morning, resting IOP and the BP were measured and the subject undertook the dynamic exercise using the bicycle ergometer and the IOP's and the BP were measured at the end of the test. STATISTICAL ANALYSIS: were done using Paired 't' test. RESULTS: IOP decreased by 2.58±0.16 mmHg(R) eye & 2.64±0.09 mmHg (L) eye during exercise using Hand grip dynamometer and the systolic and diastolic blood pressures increased by 14.73±0.87 & 12.98±1.01 mmHg respectively. The changes were statistically significant (P<0.001). IOP decreased by 2.55±0.07 mmHg(R) eye & 2.49±0.1 mmHg(L)eye following exercise using bicycle ergometer and the systolic increased by 15.73±1.71 mmHg and the diastolic decreased by 10.83±2.46 mmHg. The changes were statistically significant (P<0.001). There was no correlation between the changes in BP to the changes in IOP. CONCLUSION: IOP decreased in both static and dynamic exercises. There was no correlation between the changes in BP to the changes in IOP.
BACKGROUND: Intra ocular Pressure (IOP) changes during Valsalva manoeuver (VM). AIM: To study the effect of Valsalva manoeuvre on IOP and the heart rate response. MATERIALS AND METHODS: The study group consisted of 55 volunteers, visually normal as subjects, 30 boys and 25 girls in the age group of 18 to 20 years. Independent measurements of the IOP of each eye were obtained with the subject in the upright position. ECG recorded continuously before, during and after the Valsalva manoeuvre. Keelar Pulsair air impulse tonometer was used in all the subjects for IOP measurement. IOP was measured in the department of Ophthalmology, Teaching Hospital between 08AM to 10 AM. STATISTICAL ANALYSIS: were done using Paired 't' test. RESULTS: The mean IOP increased by 5.53±2.138 mmHg during VM. The changes were statistically significant (<0.001). Mean IOP decreased by 2.085±0.367 mmHg during VM in a small proportion of subjects (12%) which was not statistically significant. Mean recovery IOP was also lower than the resting IOP which was statistically significant (<0.001). The Valsalva ratio is calculated as the ratio of the longest RR interval (ms) after the maneuver divided by the shortest RR interval (ms) during the test. Mean Valsalva ratio was normal at 1.687 (range 1.2-2.6). CONCLUSION: IOP increased during Valsalva manoeuvre in a large number of subjects (88%). Recovery IOP was also lower than the resting IOP during the period of measurement, post VM (over a period of 5 minutes).
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