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Browsing by Subject "Tooth Mobility"
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Item A Study of Tooth Rotation in the Macque Speciosa Monkey(1970) Scott, Harry Eugene, Jr.; Barton, Paul; Cunningham, Donald M.; Standish, Miles S.; Jordan, David R.This study was undertaken to observe the effect of light, medium, and heavy couples on multirooted teeth of three young male Macaque speciosa monkeys. Three forces of 82 gm.-mm, 245 gm.-mm, and 2280 gm.-mm. were generated from closed-coil springs for a period of 42 days. The rate of tooth movement varied among all three forces, with the average rates being similar when comparing the three forces over the 42-day period. All three forces produced an initial, lag, and post-lag phase of tooth movement. The center of rotation of the three-rooted tooth appeared to be close to the lingual root while in the two-rooted tooth the center of rotation was close to the center of the tooth. Hyalinization and root resorption were seen with all forces and increased with increased force. Hyalinization and root resorption were more severe in the smaller diverging apical portion than in the cervical portion of the roots.Item Force Values and Rate of Movement in Closure of Space Between Maxillary Central Incisors(1962) Levihn, Henry L.A study was conducted to determine the rate of tooth movement, pain response and tooth mobility when closing the space between the maxillary central incisors. Twenty children age 8 to 18 were selected who had a minimum of two millimeters space between the maxillary centrals. The forces used were 10, 20, 50, 75, 125, and 200 grams. It was found that there was a fast initial movement followed by a latent period of varying lengths of time. In most instances the lag period is from seven to ten days, but in three cases it was as high as eighteen to twenty-five days. The five patients in the 50 gram group had the shortest latent period. The three patients with the extended latent periods happened to be the three oldest patients in the sample. That is, they were from 16 ½ to 18 years of age, while the average age for the entire sample was about 11 years. After the latent period, the rate of movement in the 10 and 20 gram groups was slower than the rate of movement with higher force. When the higher forces in the 125 and 200 gram range were used, the rate did not continue to increase but was comparable to the rates in the 50 and 75 gram groups. What was noticed in the higher range of force was an increase in the amount of pain and mobility. From these observations it was felt that for tipping of the maxillary centrals the optimal range of force to be used would be 50 to 100 grams. At these forces the rate of tooth movement was rapid and the patient’s response to pain was at a minimum.Item A Histologic and Cephalometric Investigation of Premolar Intrusion in the Macaque Speciosa Monkey(1965) Dellinger, Eugene L.It has been debated as to whether teeth may actually be intruded in their alveoli. This study was designed to measure the intrusive movement and histologic response of specific teeth to a known intrusive force. Four Macaque speciosa monkeys were used. The animals corresponded in age to a 12-14 year old human being. Intrusive forces of either 10, 50, 100, or 300 grams were placed on the maxillary first premolars; each force value was held constant during the duration of the experiment, which was 60 days. Maxillary first molars were used as anchorage. Cephalometric headplates proved that all force values were capable of giving intrusion. The 50 gram forces, however, gave the most efficient intrusion. Histologic sections were made on all experimental teeth. 300 and 100 gram forces gave excessive root resorption but the 50 and 10 gram force values elicited only slight root resorption. Root resorption seemed to be directly related to excessive force. The amount of intrusion was not related to a loss of root structure. Bone resorption appeared to allow the intrusion of teeth with minimal tissue damage if proper force values were used.Item A Histologic Investigation of Orthodontic Tooth Movement in Hypothyroid Macaque Speciosa Monkeys(1974) Davis, Steven L.; Garner, LaForrest D.; Barton, Paul; Tomich, Charles E.; Mitchell, David F.; Chalian, VaroujanThis study was undertaken to histologically evaluate orthodontic tooth movement in hypothyroid and in normal Macaque speciosa monkeys. The experimental animals were rendered hypothyroid by radiosurgically altering the thyroid gland. A clinically acceptable orthodontic force was delivered to the anterior teeth of the monkeys. After the desired movement, a histologic investigation was made to correlate tissue responses with pressure, tension and root resorption. There was no significant difference among the three experimental animals. Likewise, there was no significant difference between the control animal and the three experimental animals. Osteoblastic and osteoclastic activity occurred to a comparable degree in both the experimental and control animals and was within normal limits for the amount of orthodontic tooth movement achieved. Root resorption was evident in both orthodontically treated and non-treated teeth in both the experimental and control animals. The root resorption observed was not significantly different, quantitatively or strategically, between the experimental and the control animals. Repair of root resorption was evident in both the experimental and control animals.Item An Investigation of Depressive Root Movement in the Macaque Speciosa Monkey(1973) Clevenger, Victor Reid; Bixler, David; Mitchell, David F.; Tomich, Charles E.The purpose of this study was to investigate the possibility of accomplishing simultaneous intrusion and distal root movement of monkey premolar teeth utilizing the molar teeth as anchorage. Four Macaque speciosa monkeys were used as the experimental specimens. Root springs of the type used in the segmented arch technique were used to apply unequal moments to the premolar and molar teeth. The root movement was accomplished by a couple generated by the unequal moments. The results were analyzed cephalometrically and histologically. It was found that it is possible to accomplish distal root movement and intrusion of the monkey premolars when the anchorage is restrained from eruption. When the anchorage is not restrained intrusion is minimal. Root resorption was found to be associated with the magnitude of the difference in the moments applied and the amount of tooth movement.Item Orthodontic Movement and Return of the Root Apex Through the Cortical Plate in the Macaque Speciosa Monkey(1970) Wainwright, W. Michael; Garner, LaForrest D.; Shafer, William G.; Cunningham, Donald M.; Norman, Richard D.During orthodontic therapy, the apices of teeth are sometimes moved or tipped against and even through the cortical plate of bone. This may be a final tooth position or the root may then be brought back into cancellous bone. The purpose of this study was to observe histologically the effects of these movements and of retaining the root in these positions. Four Macaque Speciosa monkeys were used. Their ages corresponded to late adolescence in the human. The force system used to achieve the desired tooth movement on the animals' teeth was calculated from a force system which from clinical experience is considered to be optimal in root movement in humans. This force system was kept constant. Procion Brilliant Red H-8BS was used as a vital marking agent and was administered once to each animal prior to the last stage of movement in each case. As the root apex penetrated the cortical plate, the buccal surface was the only root surface that became devoid of bone. There was considerable proliferation of cortical plate which "followed" the root and maintained its relationship to bone on the remaining root surfaces. During a four month retention period there was continued osteogenesis of the buccal surface of the cortical plate, but the root apex was not completely covered. Bone apposition also occurred on the lingual surface of the buccal plate and there was remodeling of the osteophytes. As the root was moved back and retained, there was complete repair of the perforation site with further slight thickening of the cortical plate. Root resorption was present on the buccal surface when it was under pressure, and the lingual surface on reversal of the force system. The resorption was increasingly severe towards the root apex. Although the tooth movement was 50 percent faster on the reversal movement, the severity of resorption was comparable on buccal and lingual surfaces. Cellular cemental repair was considerable and was most marked at sites of greatest recent root resorption and on the tension side of the tooth in movement. Less cemental deposition occurred on the mesial and distal root surfaces. Since the appliances were reactivated monthly, areas of hyalinization were rare. There was no inflammation due to tooth movement and the pulp tissue was normal in all cases.Item Tooth Mobility and Instantaneous Centers of Rotation(1964) Christiansen, Richard LouisTooth mobility as it relates to orthodontics has not been thoroughly explored. The immediate aim of this project was to develop and test instrumentation to measure both tooth mobility and instantaneous centers of rotation under forces applied perpendicular to the tooth long axis. Two identical dial micrometers were selected and modified to allow variability in range, calibration, and contact pressure. All forces were delivered by mechanical force meters. A holding device was constructed to permit rigid positioning of a micrometer perpendicular to the long axis of any tooth in the arch and measure mobility at one point on the tooth. With an applied force of 500 gm., mobility measurements were made with the instrument on 44 teeth of six orthodontic patients. By repeating the analyses the instrument reproducibility was demonstrated. The pattern of tooth movement to applied force was explored and related to possible stress levels in tipping movements. A second holding device allowed both micrometers to contact a dental extension which was fixed to a maxillary central incisor. An incisor from each of four preorthodontic and two postorthodontic patients was analyzed. Over 200 clinical centers of rotation were calculated from measurements of tooth movements at two points on the tooth's long axis. Results from the first three patients were erratic. The rotation centers of the last three patients generally remained at midroot and also near the theoretical center of the tooth for all forces applied over 50 gm. More comprehensive studies on tooth mobility are recommended.Item Translation of Premolars in the Dog by Controlling the Moment to Force Ration on the Crown(1968) Fortin, Jean Marc; Norman, R.; Cunningham, D.; Shafer, W.The main purpose of this investigation was to produce bodily tooth movement. A force system based on the moment to force ratio (m/p ratio) was developed and applied to the teeth by means of springs similar to those used in segmented arch technique. An histologic investigation followed the experimentation. The sample consisted of five adult dogs and a relatively young one, all males. On these dogs, light forces of 165 and 147 gms were used for a period of 17, 30 and 35 days. and heavy forces of 490, 450 and 455 gms were used for a period of 120, 107 and 106 days. An intraperitoneal injection of a vital dye, procion red H8BS, was made before placing the appliance in the mouth and used as a marker between old and new bone. Bodily tooth movement was assessed by measuring new bone apposition on the tension side. Most of the teeth did show pure bodily movement, however, slight tipping was noticed in some instances. Direct bone resorption was recorded in all the teeth moved with light and heavy forces with the exception of very few small areas of hyalinization. The only difference between light and heavy forces was in the severity of root resorption. It was found that the heavier the force, the greater was the anchorage loss. The rate of tooth movement was continuous but not constant.