IU Indianapolis ScholarWorks :: Browsing by Subject "Orthodontics, Corrective"

Browsing by Subject "Orthodontics, Corrective"

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A Cephalometric Analysis Comparing Anteroposterior Mandibular Growth of Treated and Non-Treated Cl 1 and Cl II, Patients
(1971) Tillmanns, David V.
This study was conducted to investigate any anteroposterior mandibular growth that occurs after orthodontic treatment is completed and to determine how it might compare with growth in untreated subjects of comparable age. The research sample consisted of 15 males and 23 females who prior to orthodontic treatment had either an Angle Class I or Class 11 division 1 malocclusion. The control group of 14 males and 16 females had normal Class I occlusions. All subjects were Caucasians. A standardized technique for taking lateral cephalometric radiographs was used at the time of debanding and 2 1/2 to 4 1/2 years later for follow up (post-treatment) radiographs. The deband and post-treatment radiographs of each subject were traced and superposed. Measurements were compared to the expected normal values of the control group at a comparable age. With the “t” test, the following significant differences of 0.05 probability or less were found. Effective mandibular length was less than normal in the male Class II treated malocclusion at the time of debanding, and actual mandibular length was greater than normal in the female Class I treated malocclusion at the time of deband and post-treatment periods. Growth was compared between the Class I and Class II treated malocclusion samples within each sex group. No significant differences were observed which suggests that the growth potential of the mandible, with either a Class I or Class II malocclusion, will be the same after treatment.
A Study of the Correlation of Incisive Biting Forces with Age, Sex and Anterior Occlusion
(1971) Kotwal, Navroze Shavak; Standish, S. Miles; Chalian, Varoujan A.; Shanks, James C.
This study was designed to prove or disprove the fact that incisive biting force can be correlated with the variables chosen which were age, sex and anterior occlusion (overjet, overbite and cuspid relation). The amount of linear contact made by the incisal edges of the upper and lower incisors was also included as one of the variables. One hundred and fifty individuals, 80 males and 70 females, between the ages of 10 and 25 were selected for this study. This was a cross sectional study in which four readings of the maximum biting ability were recorded for every individual just once during the study and an average of the four recordings was taken. An intra-oral force transducer using strain gages was employed to record incisive biting forces. The results indicated that age, sex and amount of linear contact were correlated with biting force when considered singly. When the variables were considered jointly through a stepwise regression analysis overbite also entered as a significant predictor of biting force in addition to the three mentioned variables. Multiple correlation coefficient R was 0.54 for the four entered variables (age squared, sex, overbite and linear contact squared) with biting force. The R squared value was 0.29 so that 29 percent of the variation in incisive biting force of this sample was due to these four variables. The correlated R-squared value indicates a large error of prediction and a low degree of precision in estimating biting force from these four variables. Therefore, a regression equation is not demonstrated.
Antero-Posterior Movement of the Maxillae with a Modified Sutural Expansion Device
(1967) Gersh, Gary Paul
It was the purpose of this study to discover if anteroposterior movement of the maxillary bones was possible. Seven cats were used as the experimental animals. An expansion device which produced a diagonal force from one maxillary cuspid to the opposite molar was inserted in five of the animals. Two animals were used as controls. The effects of the lateral and antero-posterior components of the force were studied by means of before and after models, oriented occlusal radiographs, and histologic sections. Antero-posterior movement did occur. The anterior movement was more evident than the posterior movement due to the response evoked in the premaxillary-maxillary and the maxillary-palatine sutures. The sutures which were compressed showed very little response when viewed in horizontal histologic sections as compared to the sutures which were under tension. The sutures under tension showed marked osteophytic production which generally grew parallel to the line of force application. This difference in response allowed one side to remain as an anchorage unit while the opposite side moved anteriorly. The lateral increase in width appeared to be stable. In one animal the force was removed for thirty six days prior to sacrifice. In this animal the stability of the antero-posterior movement was questionable.
A Comparison of Frictional Forces During Simulated Cuspid Retraction on a Continuous Edgewise Archwire
(1982) Allai, W. Wesley; Garner, LaForrest D.; Sondhi, Anoop; Shanks, James C.; Swartz, Marjorie L.; Barton, Paul
This investigation was designed to compare the force (grams) required to overcome a simulated cuspid retraction assembly capable of three dimensional control during the retraction process. It was hypothesized that a significant difference in the mean retraction values exists between the newer orthodontic alloys of Nitinol, Beta-Titanium, as well as Stainless Steel. One hundred eighty bracket and archwire combinations were examined as follows: Sample # Wire Cross-section Wire Material 30 .016”x.022” Stainless Steel 30 .017”x.025” ” 30 .016”x.022” Nitinol 30 .017”x.025” ” 30 .016”x.022 Beta-Titanium (TMA) 30 .017”x.025” ” A statistically significant difference was shown to exist between all six groups examined regarding the variables of wire size and wire material. The statistical analysis revealed that increasing rectangular archwire cross-sectional size from .016"x.022" to .017"x.025” rectangular wire when simulating canine retraction using an .018" slotted Lewis bracket will lead to significantly greater functional forces. The analysis of wire materials indicated that a significant difference (p=.01) exists between rectangular Beta-Titanium (TMA), Nitinol, and stainless steel during simulated cuspid retraction utilizing a narrow .018" Lewis bracket ligated with A-lastik ligatures. The least frictional force was observed with the .016"x.022" stainless steel test cells. The largest frictional force was found in the .017”'x.025" Beta-Titanium retraction specimens. Nitinol revealed force data intermediate between stainless steel and Beta-Titanium. The maximum resistance assembly developed 2.3 times the minimum frictional force observed. The mean grams of frictional force within these test cells ranged from 55.03 grams for the .016"x.022" retraction assembly to 132.68 grams for the .017"x.025" Beta-Titanium assembly. A topographical scanning electron microscope survey of the brackets and archwires utilized was included to provide qualitative insights into the quantitative results described.
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.
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.
Three-dimensional image analysis for quantification of tooth movements and landmark changes
(2013-12-11) Li, Shuning; Chen, Jie; Christopher, Lauren; Bajaj, Anil K.; Katona, Thomas R.; Adams, Douglas E.; Anderson, David C. (David Carleton), 1948-
Quantification of treatment outcomes (tooth displacement and bony changes) is the key to advance orthodontic research and improve clinical practices. Traditionally, treatment outcome were quantified by using two-dimensional (2D) cephalometric analysis. However, there are problems inherent in 2D analysis, such as tracing errors and inability to detect side-effects. Thus, a reliable three-dimensional (3D) image analysis method for treatment outcome quantification is of high interest. Systematic 3D image analysis methods were developed for digital dental cast models and Cone-Beam Computed Tomography (CBCT) models. A typical analysis procedure includes image reconstruction, landmarks identification, coordinate system setup, superimposition, and displacement or change calculation. The specified procedures for maxillary teeth displacements and anatomical landmarks movements were presented and validated. The validation results showed that these procedures were accurate and reliable enough for clinical applications. The 3D methods were first applied to a human canine retraction clinical study. The purposes of this study were to quantify canines and anchorage tooth movements, and to compare two commonly used canine retraction strategies, controlled tipping and translation. The canine results showed that (1) canine movements were linear with time; (2) the initial load system was not the only factor that controlled the canine movement pattern; and (3) control tipping was significantly faster than translation. The anchorage tooth results showed that (1) anchorage losses occurred even with transpalatal arch (TPA); (2) there was no significant difference in anchorage loss between the two treatment strategies; and (3) compared with removable TPA, fixed TPA appliance can significantly reduce the amount of anchorage loss in the mesial-distal direction. The second clinical application for the 3D methods was a mandibular growth clinical trial. The purposes of this study were to quantify skeletal landmark movements, and compare two widely used appliances, Herbst and MARA. The results showed that (1) the Herbst appliance caused mandibular forward movement with backward rotation; and (2) the treatment effects had no significant differences by using either Herbst or MARA appliances. The two clinical applications validated the methods developed in this study to quantify orthodontic treatment outcomes. They also demonstrated the benefits of using the 3D methods to quantify orthodontic treatment outcomes and to test fundamental hypotheses. These 3D methods can easily be extended to other clinical cases. This study will benefit orthodontic patients, clinicians and researchers.
Threshold Force Values for Anterior Retraction
(1959) Groves, Murray H., Jr.
A method was devised and described to study the tissue response as demonstrated by tooth movement to measured force loads in the range of from 25 to 150 grams force a side or from 50 to 300 grams distributed over the maxillary central and lateral teeth. Investigation was initiated in an attempt to establish the existence or non-existence of threshold force values for anterior tooth movement. Threshold forces are defined in this study as that force necessary to retract the maxillary central and lateral teeth one millimeter. Secondary objectives were to determine whether there is similar tooth movement demonstrated by individuals at given force values, the relation of force and pain response at low force values, whether there is movement of the anchor teeth and whether there is an optical range force for anterior retraction. An optimal range of force would be a range where there was maximum tooth movement with a minimum of pain response. Before and after records were taken on twenty-two children which consisted of models, lateral cephalometric radiographs and before treatment photographs. All the children possessed maxillary protrusions with space distal to the lateral teeth as a criterion for selection for the study. The maxillary central and lateral teeth were branded and brackets were placed at a determined distance from the incisal edge of the central teeth so as to standardize the force at the alveolar crest regardless of root length. The maxillary molar teeth were banded and a soldered lingual bar constructed to extend from light to left molar. Eyelets were welded to the buccal surface of these molar bands as fixed points of reference for measurement of the amount of movement of the maxillary four anterior teeth in relation to the molars. Measurement was made with a Korkhaus Three Dimensional Orthodontic caliper and by superimposition of lateral cephalometric headplates. Measurements were taken at seven, twelve, seventeen, twenty-two and twenty-seven days after activation of .008 X .030 closed coil springs in tension on the right and left side of the appliance. The load deflection of the coil springs was 13 grams per millimeter. The range of forces from 25 to 150 grams a side are termed low force values in this study. At these low force values there is similar tooth movement demonstrated by all individuals in the study. Threshold force values appear to be a range of force values of from 14 to 24 grams distributed to the four maxillary anterior teeth. These low force values of from 25 to 150 grams on the right and left side create no severe or prolonged problems for the patient. In no case was pain described as more than a slight soreness. There appears to be no movement of the anchor teeth as determined by the method used in this study. An optimal range of force values for the retraction of the four anterior teeth is in the range of from 50 to 75 grams a side or from 100 to 150 grams distributed over four teeth.
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.
Understanding mechanical environment changes and biological responses to canine retraction using t-loop
(2015-05) Jiang, Feifei; Chen, Jie; Bajaj, Anil; El-Mounayri, Hazim; Katona, Thomas; Nauman, Eric
Predictability of tooth displacement in response to specific orthodontic load system directly links to the quality and effectiveness of the treatment. The key questions are how the tooth’s environment changes in response to the orthodontic load and how the biological tissues respond clinically. The objectives of this study are to determine the mechanical environment (ME) changes and to quantify the biological tissues’ response. Eighteen (18) patients who needed maxillary bilateral canine retractions were involved in the study. A method was developed to quantify the 3D load systems on the canine, which allowed the treatment strategies to be customized in terms of orthodontic loading systems to meet either translation (TR) or controlled tipping (CT) requirement. Dental casts were made before and after each treatment interval, and the Cone Beam Computed Tomography (CBCT) scans were taken prior to and following the entire treatment for control of treatment strategy and post treatment evaluations. Finite element method (FEM) was applied to calculate the location of center of resistance (CRes) for tooth movement control. The location and variation of CRes were recorded and compared with previous studies. A quick CRes assessment method that locates CRes by calculating the centroid of the contact surface (CCS) and the centroid of the projection of root surface (CPCS) in certain direction was also tested and compared with the results from FEM. Customized T-loop spring, a kind of orthodontic appliance, was designed, fabricated, and calibrated on a load measuring system to ensure that the load met the clinician’s prescription. The treatment outcomes in terms of tooth displacement and root resorption characterized by the changes of tooth length and volume as well as the bone mineral density (BMD) represented by the Hounsfield units (HU) change were recorded and analyzed. The ME in terms of stress were also calculated by using FEM. Paired t-test and mixed model ANOVA methods were used to analyze the relationships between the mechanical inputs (quantified and customized load, and corresponding stress) and clinical outcomes (root resorption and BMD change). It was found that the overall root resorption is not significant for canine retraction, but apical root resorption does occur, meaning that orthodontic load is not a sufficient factor. Also, it was observed that HU distribution changed significantly in both root and alveolar bone. The maximum reduction was on the coronal level in the direction perpendicular to the direction of movement in root, and in the direction of the tooth movement at the coronal level in bone. In addition, it was determined that the locations of the CRes in the MD and BL directions were significantly different. The locations of the CRes of a human canine in MD and BL directions can be estimated by finding the CPCSs in the two directions. Finally, it was shown that the stress invariants can be used to characterize how the osteocytes feel when ME changes. The stress invariants in the alveolar bone are not significantly affected by different M/F. The higher bone modeling/remodeling activities along the direction of tooth movement may be related to the initial volumetric increase and decrease in the alveolar bone.

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