IU Indianapolis ScholarWorks :: Browsing by Subject "Tooth Movement Techniques"

Browsing by Subject "Tooth Movement Techniques"

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Assessment of Dental Asymmetry Utilizing Orthodontic Study Casts Comparing Tooth Positions to the Midpalatal Raphe and Tooth Size Among Antimeres
(2002) Sprowls, Matthew W.; Hartsfield, James K., Jr.; Baldwin, James; Everett, Eric T.; Hathaway, Ronald; Shanks, James C.; Ward, Richard E.
Several studies have been conducted in relation to the treatment and etiologies of craniofacial and dental asymmetries in the orthodontic scientific literature. However, limited research has attempted to correlate asymmetry in dental traits to each other. The purpose of this research study was to develop a better understanding of the correlations between dental arch asymmetry and dental tooth size asymmetry and their underlying causes. Understanding asymmetries is essential in orthodontic diagnosis and treatment planning. An orthodontist cannot obtain an optimal occlusal and functional result without properly balancing skeletal and dental relationships. Pretreatment dental study casts of 86 sequential patients from the postgraduate orthodontic clinic at the Indiana University School of Dentistry were used for the analysis. Each patient was analyzed in a single blind fashion to minimize bias. The Adobe Photoshop® ruler and Chicago® brand electronic digital calipers accurate to the nearest tenth of a millimeter were used for digital measurements. Measurements were made to determine the amount and direction of asymmetry along the dental midlines relative to the median palatine raphe. Transverse and sagittal measurements were made to record asymmetries in canine and molar positioning. Furthermore, three sets of antimeric maxillary teeth were measured for length and width. These included the central incisors, the canines, and the first molars. Fluctuating asymmetry was present in all measurements, except molar distance to median palatal raphe. This was found to be directional to the left in the entire sample group. Statistical analysis was subsequently performed and the results showed significant correlations in the individuals in the subsample dentition group. Subjects belonging to this group with a measurable degree of fluctuating asymmetry had a greater tendency toward transverse maxillary discrepancies as measured from the canines and first maxillary molars relative to the median palatal raphe. Moreover, individuals in the subsample group with above average total weighted fluctuating asymmetry values according to the parameters analyzed in this study appeared more likely to have decreased developmental stability leading to the clinical expression of more severe malocclusions.
Digital Radiographic Analysis of Mineral Density of Adjacent Alveolar Bone in Relation to the Molar Translation Rate After Use of Retromolar Implant Anchorage
(1997) Sim, Yeongsuk; Roberts, W. Eugene; Analoui, Mostafa; Hohlt, William F.; Katona, Thomas R.; Shanks, James C., Jr.
Molar translation using retromolar implants provides an unique opportunity to measure the rate of orthodontic tooth movement, because implants do not permit any reactive movement from the force. Contrast-corrected digital radiography was utilized to investigate the rate of molar translation related to the mineral density of adjacent alveolar bone. It was hypothesized that the rate of molar translation was inversely correlated with bone mineral density ahead of the moving tooth. Periapical radiographs were obtained every six months during 24 months of active treatment of eight patients (age: 24 to 48 years). Distance from three reference points (crown tip, mid-root, apex) and mineral density of four circular areas in front of the translating molar were analyzed for correlation. The primary method of analysis was the use of Pearson correlation coefficients between rate change and bone mineral density, and between rate change and age. The results showed that rate change of molar translation at the root apex was inversely correlated to the mineral density of adjacent alveolar bone. The correlations were not significant when examining the rate over the first six months; however, the correlations were significant after the second follow-up evaluation at 12 months. The correlation was also significant when using the overall means up to last follow-up visit. However, patient age was not significantly related to the rate of molar translation in this study.
Force Values and Rate of Distal Movement of the Mandibular First Permanent Molar
(1959-11-01) Kuhn, Robert J.
A method is described for the distal replacement of mesially tipped mandibular first permanent molars in children nine to thirteen years of age. The study was designed to determine the rate of movement and pain response of this tooth when relatively light specified forces were applied for distal movement. This study was undertaken in the light of recent evidence which suggests that forces many times lighter than those currently employed may enhance rate of movement, diminish the amount of root and periodontal damage, and practically eliminate pain usually associated with tooth movement. The sample was composed of children who had prematively lost deciduous mandibular second molars with resultant mesial tipping of the first permanent molar. There were eighteen cases in the sample of fifteen children, three of the children exhibiting bilateral loss. The method of movement employed a sine loop helical torsion spring attached to a soldered lingual appliance to effect distal molar movement. This appliance was so fabricated to utilize all of the teeth anterior to the primary second molar space as anchorage. Extensive records were taken before treatment began, during active treatment, and at the time of retention. These included models, lateral headplates, periapical radiographs, oriented occlusal radiographs, and direct divider measurement in the mouth. The children were routinely examined every four to ten days and appropriate records and measurements taken at these appointments. It was found in those cases in which under 80 grams had been applied to the teeth there was one pattern of movement while in those above 100 grams another general type was observed. In the below 80 gram group there was a relatively large (0.69 mm.) initial increment of space opening in the first week followed by a one – two week latent period of non-movement. Movement then continued at an average of 0.22 mm/week. The 100 gram group exhibited a very small initial movement (0.27 mm) followed by a two-three week latent period. Movement then continued at a rather rapid rate, (0.39 mm/week). Flaring of the anchorage united was noted in all but one case. The amount ranged between 1 and 2 mm. in four to six weeks. The cases above 100 grams appeared to show the largest amount of flaring. Pain usually associated with tooth movement was non-existent in the patients where below 70 grams of force was applied. The intensity of the pain response in the cases above 70 grams (70 – 194) appeared generally to coincide with the magnitude of force application. The many difficulties and variables associated with distal mandibular molar movement are discussed in detail. These include tooth inclination, occlusion and interlocking, relationship of the second permanent molar, and root configuration. Based on the results of this study, it is suggested that threshold forces for tooth movement may be non-existent and that any force if allowed to remain on a given tooth for a sufficient length of time will elicit tooth movement. The evidence shown both in this study and by other investigators point to the possibility of an optimal range of force for tooth movement.
Fractal Analysis to Detect Surface Roughness Changes After Fatique Loading in the Canine Mandibular Incisor - A Pilot Study
(2006) Hayes, Andrew M.; Katona, Thomas R.; Baldwin, James J.; Hohlt, William F.; Platt, Jeffrey A.; Shanks, James C.
A common occurrence resulting from orthodontic treatment is iatrogenic root resorption. Experimentally, histological sections are usually employed to study root resorption utilizing special staining techniques. Although this has been shown effective for decades, results are limited to extracted teeth. Clinically, root resorption is detected and evaluated with standard radiography. This technique is limited to evaluating the 3-dimensional phenomenon of root resorption with 2-dimensional films. Quantifying these results has proven to be cumbersome if not impossible. Recent advances in computed tomography are allowing researchers to evaluate changes in the skeleton, including dental movements in three dimensions. CT reconstructions could be used to evaluate the changes in tooth composition through the volumetric data obtained. Fractal analysis techniques have become irreplaceable in the understanding of many phenomena in various scientific fields such as astrophysics, economy, geology, ecology and agriculture. Recently, a significant amount of literature has been published describing the expansion of this technique into the fields of bio-medicine, including dentistry. The logic behind fractals is derived by observing an object through successive scales. Fractal analysis can be used to measure an object's space filling properties. Simply put, the more space the object occupies, the higher the fractal dimension. The purpose of this study is to utilize fractal analysis to quantify morphological changes in ex vivo root structure from fatigue loaded mandibular central incisors of canine (hound) specimens. After fatigue loading experimental teeth, microcomputed tomography, was used to obtain 3-dimensional data of both the experimental and control teeth. Computer software was used to develop 3-dimensional models of each specimen and fractal analysis was performed on specific regions of each tooth. To obtain the specific regions, the root was divided into 5 planes or slices horizontally, beginning with the most cervical portion to the apical portion, then further divided into a buccal and lingual portion. These can be systematically evaluated using a coordinate system of numbering from 1-10, starting with the cervical-buccal region of the root (zone 1) to apical-buccal (zone 5). The numbering then follows to the opposite side of the tooth with the cervical-lingual region (zone 10). Changes in surface roughness were detected through the fractal analysis and compared between the control and experimental animals. Statistical analysis showed that the mean roughness of the experimental group was significantly smaller than in the control group for two of the ten zones tested in each tooth.
Histologic Tissue Rearrangement Following a Circumferential Supracrestal Fiberotomy on Orthodontically Rotated Teeth in Dogs
(1987) Powell, Mark L. M.; Garner, LaForrest D.; Sondhi, Anoop; Kafrawy, Abdel; Standish, S. Miles; Shanks, James
The purpose of this study was to determine whether a circumferential supracrestal fiberotomy has a biologic basis in the management of rotational relapse. The maxillary second incisors of seven beagle dogs, approximately two years of age, were rotated orthodontically from nine to 52 degrees. The incisors were retained. A circumferential supracrestal fiberotomy was performed twice unilaterally on the maxillary left second incisor of six dogs by incising through the gingival crevice parallel to the long axis of the tooth. The seventh dog was sacrificed and used for comparison of the tissue rearrangement after rotation but before fiberotomy and/or retention. The remaining dogs were paired for retention periods of one, three, and six months. Ten days before sacrifice all seven dogs were injected intraperitoneally with procion brilliant red H-8BS to determine appositional activity. At the end of the respective retention periods, the dogs were sacrificed and the specimens were fixed, decalcified, and serially sectioned horizontally, perpendicular to the long axis of the teeth. Sections were stained with H and E for histologic examination using light microscopy. Some sections were left unstained for evaluation of procion labelling using fluorescent light microscopy. The rearrangement of the subcrestal periodontal ligament fibers was determined by whether they produced a force capable of causing an increased alveolar and/or cemental apposition and not by their angulation to the root surface. The results failed to support a biologic basis for performing circumferential supracrestal fiberotomies on orthodontically rotated teeth. The supracrestal fiberotomy combined with retention had no additional effect on increasing the rearrangement of the supracrestal tissues compared to retention alone. Six months of retention, with and without a supracrestal circumferential fiberotomy, was sufficient for the supracrestal tissues to rearrange. Some of the subcrestal periodontal fibers in the tension and pressure areas at six months in retention may play a role in relapse. Undermining root resorption was evident in some pressure areas. Neither the angulation of the subcrestal and supracrestal periodontal fibers to the tooth surface nor the angulation of the epithelium was an accurate measure of the amount of tissue rearrangement. The circumferential supracrestal fiberotomy caused a cemental hyperplasia adjacent to areas nicked by the scalpel blade.
Testing of Orthodontic Springs Using Geometric Variables
(1995) Markham, David; Chen, Jie; Katona, Thomas R.; Arbuckle, Gordon R.; Baldwin, James J.; Shanks, James C.
A common method of space closure utilizes loops formed in orthodontic arch wires. The loops must provide adequate force characteristics to maintain controlled tooth movement. Generally, a moment-to-force (M/F) ratio of 10 mm is considered effective. The 1/2 Baldwin Spring is an effective loop, but it is difficult to fabricate and potentially irritating in the oral cavity. T- and L-loops are commonly used in orthodontics. They are conceivably less effective for controlled tooth movements but are simple to fabricate and relatively more comfortable in the oral cavity. This study demonstrates how altering the vertical and horizontal dimensions of the T- and L-loops affects their force characteristics. The vertical dimensions were 6 mm and 7 mm for the T- and L-loop. The horizontal dimensions were 6 mm, 7 mm, and 8 mm for the T-loop and 4 mm, 5 mm, and 6 mm for the L-loop. The experimental groups were named according to loop shape, vertical dimension, and horizontal dimension: T66, T67, T68, T76, T77, T78; L64, L65, L66, L74, L75, L76. Specimens were fabricated from 0.016 in x 0.022 in stainless steel and tested at 1 mm, 2 mm, and 3 mm horizontal activation distances (dx). Then they were preactivated by 30° gable bends, heat-treated (30°-htx), and tested again. Experimental data collection included the moment about the z axis (Mr) and the force along the x axis (Fx). TheMr/ Fx ratio was calculated. The T-loop with 30°-htx provided the highest M/F ratios at 1 mm dx and ranged from 5.15 mm (T68) to 6.67 mm (T67) (p<0.05). The T77 with 30°-htx exhibited the most consistent M/F ratios at 1 mm, 2 mm, and 3 mm dx: 6.09 mm, 6.01 mm, 6.04 mm consecutively (p~.6309). The L-loop provided scattered data ranging from -0.50 mm (L65) to 4.15 mm (L75). In general, 30°-htx increased the M/F ratio in all groups. T6* loops provided higher M/F ratios than TT* loops at small dx. T*8 loops provided consistently low M/F ratios ranging from 4.92 mm (T68) to 5.18 mm (T78). Altering the vertical and horizontal dimensions of the Tand L-loop significantly affects their force characteristics (p<0.05). None of the geometrically altered T- and L-loop designs provided ideal M/F ratios. These data suggest that the best T-loop designs for space closure are T66,T67, and T77.
The Relation between Force Magnitude and the Center of Rotation in the Maxillary Incisor
(1962) Kulis, LeRoy Howard
When a tooth is tipped, it moves about a center of rotation, but the exact location of this center has been the subject of much discussion and confusion. This study was designed to locate the centers of rotation of upper central incisors by application of known forces to the teeth of fourteen patients. Records were taken to ascertain the rate of movement and pain threshold, and the axis of rotation was located by superposing accurate periapical films. The results show that there is no significant difference in the centers of rotation when forces of 51 and 121 gms. were used. The teeth tipped about points located apically at 1.2 and 1.2 mm. from the centroid of the root for groups studied. The teeth moved most rapidly immediately following the first application of force, and then a lag period followed with no tooth movement. This was followed by a steady small incremental rate until the space closed. The pain threshold dropped greatly during the first day of tooth movement. The direction and type of tooth movement were able to be observed on the films. Both the rate of movement and the pain response recorded concurred with observations made daily in the clinic. This study was designed to test the validity of the Moment/ Force Ratio used to locate the centers of rotation. The results obtained were very close to those found using this ratio, and therefore gave clinical support to this theory. The conclusion reached by this study indicates that the procedure was able to accurately locate the center of rotation, found to be just apical by 1.2 to 1.3 mm. from the centroid of the root.
Trabecular Adaptation to Continuously Loaded Endosseous Implants
(1993) Bailey, Grant S.; Roberts, W. Eugene; Garetto, Lawrence P.; Baldwin, James J.; Nelson, Charles; Shanks, James C.
Several studies have shown endosseous implants placed in areas of thick cortical bone to be an effective means of anchorage in complex orthodontic cases. The purpose of this study was to examine the viability of endosseous implants as orthodontic/orthopedic anchorage when placed in this cancellous bone. Eighteen 6-month-old male rabbits were used and stratified into three groups of six animals. Two implants placed (bilaterally) in the dorsal surface of the nasal bones. After a 12-week healing period, the control group (C) had a passive spring placed between the implants, and the 1 Newton constant group (1 NC) received a spring that delivered a constant compressive load of 1N. A 1N load was applied to the progressive load group (3NP) and sequentially increased to 3N over the course of the study. Bone labels were administered throughout the experiment at designated time intervals to provide quantification of the physiologic activity. Following histologic processing, analyses were conducted on midfrontal sections using microradiography and fluorescent microscopy. The implants were divided into three regions: supraflange, coronal, and apical. Within each region the percent woven and lamellar bone was recorded as well as the percent bone in contact with or near the implant surface. Remodeling activity was observed by using fluorescent bone labels. In the sections analyzed using fluorescent microscopy, the regions were further subdivided into zones. Using the bone label data, bone was categorized as old bone, new woven bone, new lamellar bone and marrow space. Within animal, paired t tests revealed no significant difference between right/left implants. Data was pooled and an ANOVA run to test for difference between groups. Few significant differences were seen. Student Newman-Keuls sequential range tests were used to test between region and zone. The coronal region showed trends of more bone overall in the 1NC and the 3NP load groups p < 0.10. The apical region had less bone overall. The fluorescent data showed few significant differences between groups; however, the coronal region showed trends of more bone overall. A RAP effect was observed in the zonal analysis for new lamellar bone. Sutural remodeling was observed at the cortical plate over the nasal suture. A significant trabecular response was not seen in this study; however, the implants in the experimental groups remained stable throughout the study possibly due to the implant design. It was concluded that implants placed in thin cancellous bones are suitable for use as orthodontic/orthopedic anchorage.

Browsing by Subject "Tooth Movement Techniques"

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