Citation
Effect of Aligner Material, Duration, and Force Level on Tooth Movement

Material Information

Title:
Effect of Aligner Material, Duration, and Force Level on Tooth Movement
Creator:
Patel, Neha Dipakkumar
Place of Publication:
[Gainesville, Fla.]
Florida
Publisher:
University of Florida
Publication Date:
Language:
english
Physical Description:
1 online resource (40 p.)

Thesis/Dissertation Information

Degree:
Master's ( M.S.)
Degree Grantor:
University of Florida
Degree Disciplines:
Dental Sciences
Dentistry
Committee Chair:
WHEELER,TIMOTHY T
Committee Co-Chair:
MCGORRAY,SUSAN P
Committee Members:
NAIR,MADHU K
Graduation Date:
5/3/2014

Subjects

Subjects / Keywords:
Bones ( jstor )
Household appliances ( jstor )
Imaging ( jstor )
Medications ( jstor )
Orthodontics ( jstor )
Orthods ( jstor )
Orthopedics ( jstor )
P values ( jstor )
Teeth ( jstor )
Tooth movement ( jstor )
Dentistry -- Dissertations, Academic -- UF
aligners -- invisalign -- orthodontics
Genre:
bibliography ( marcgt )
theses ( marcgt )
government publication (state, provincial, terriorial, dependent) ( marcgt )
born-digital ( sobekcm )
Electronic Thesis or Dissertation
Dental Sciences thesis, M.S.

Notes

Abstract:
SmartTrackTM, created by Align Technologies, has a lower initial insertion force and a longer working range compared to the older EX30 material to aid orthodontic tooth movement (OTM). OBJECTIVES: To investigate the effect of SmartTrackTM on OTM in-vivo over a 25-day period compared to the EX30 material. METHODS: Aligners made of one of the two materials and programmed for 0.25mm of buccal movement of a maxillary incisor were used in 33 subjects (17 females and 16 males), 18-40 years old, for 22 hours/day for 25 days, in a randomized, blinded manner. Cone beam computed tomography (CBCT) imaging was conducted prior to tooth movement. RESULTS: SmartTrackTM achieved significantly higher mean OTM (73.1%) compared to EX30 (42.8%) by Day 14. No difference in OTM occurred from Day 14-25. Mixed modeling revealed SmartTrackTM and compliance separately provided 16% and 9% higher OTM. No difference between CBCT measurements and tooth movement was noted. CONCLUSION: SmartTrackTM achieved a higher mean OTM with a seemingly shorter lag phase compared to the EX30 material over a 25-day period. A combination of SmartTrackTM effects and compliance play a collective role in achievement optimal OTM. ( en )
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis:
Thesis (M.S.)--University of Florida, 2014.
Local:
Adviser: WHEELER,TIMOTHY T.
Local:
Co-adviser: MCGORRAY,SUSAN P.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2016-05-31
Statement of Responsibility:
by Neha Dipakkumar Patel.

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Embargo Date:
5/31/2016
Classification:
LD1780 2014 ( lcc )

Downloads

This item has the following downloads:


Full Text

PAGE 1

EFFECT OF ALIGNER MATERIAL, DURATION, AND FORCE LE VEL ON TOOTH MOVEMENT By NEHA D. PATEL A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2014

PAGE 2

2014 Neha D. Patel

PAGE 3

To my husband and family for helping me reach for the stars and to God for giving me the strength to reach that high

PAGE 4

4 ACKNOWLEDGMENTS T hank you t o my mentors, Dr. Timothy Wheeler, Dr. Susan P. McGorray, and Dr. Madhu Nair for your support and guidance through this process. Thank you t o my husband and family for their support throughout my entire residency. Thank you to my instructors, Dr. Wellington Rody and Dr. Calogero Dolce for their pearls of wisdom and patience these past three years.

PAGE 5

5 TABLE OF CONTENTS page ACKNOWLEDGMENTS .............................................................................................................. 4 LIST OF TABLES ......................................................................................................................... 6 LIST OF FIGURES ....................................................................................................................... 7 ABSTRACT ................................................................................................................................... 8 CHAPTER 1 INTRODUCTION................................................................................................................... 9 2 MATERIALS AND METHODS ......................................................................................... 14 Study Design........................................................................................................................ 14 Enrollment and Study Participation .................................................................................. 14 Collection of Data ................................................................................................................ 16 Clinical Tooth Movement ............................................................................................ 16 Radiographic Measures .............................................................................................. 16 Statistical Considerations .................................................................................................. 17 3 RESULTS ............................................................................................................................. 22 4 DISCUSSION ...................................................................................................................... 28 5 CONCLUSIONS .................................................................................................................. 34 LIST OF REFERENCES ........................................................................................................... 35 BIOGRAPHICAL SKETCH ....................................................................................................... 40

PAGE 6

6 LIST OF TABLES Table page 2 1 Outline of inclusion and exclusion criteria. ................................................................. 19 2 2 Schedule of Study Events ............................................................................................. 20 3 1 Demographics of subjects ............................................................................................. 24 3 2 Age of subjects ............................................................................................................... 24 3 3 Material differences in average percent of tooth movement at Day 14 (Pct14), Day 25 (Pct25), and time points in between (D iff3514). .......................................... 24 3 4 Material differences in average compliance on Day 14 and Day 25. ..................... 24 3 5 Average percent of tooth movement achieved between the materials and subject composition of movement groups. ................................................................. 25 3 6 Average percent of tooth movement achieved and average compliance scores for accompanying percentage groups. ........................................................... 25 3 7 Differences in average tooth movement achieved between genders. ................... 25 3 8 Comparison of CBCT Measures and Tooth Movement at Day 14 (Pct 14) and Day 25 (Pct 25). .............................................................................................................. 26

PAGE 7

7 LIST OF FIGURES Figure page 2 1 Overview of radiographic measurements of the target tooth. ................................. 21 3 1 Tooth movement (in mm) by material over the 25day study period. .................... 26 3 2 Tooth movement by gender and material over 25 days. ......................................... 27 3 3 Overall tooth movement between previous UF studies and the current study by material. ...................................................................................................................... 27

PAGE 8

8 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science EFFECT OF ALIGNER MATERIAL, DURATION, AND FORCE LEVEL ON TOOTH MOVEMENT By Neha D. Patel May 2014 Chair: Timothy T. Wheeler Major: Dental Sciences Orthodontics SmartTrackTM, created by Align Technologies, has a lower initial insertion force and a longer working range compared to the older EX30 material to aid orthodontic tooth movement (OTM). To investigate the effect of SmartTrackTM on OTM invivo over a 25day period compared to the EX30 material. Aligners made of one of the two materials and program med for 0.25mm of buccal movement of a maxillary incisor were used in 33 subjects (17 females and 16 males), 1840 years old, for 22 hours/day for 25 days, in a randomized, blinded manner. Cone beam computed tomography (CBCT) imaging was conducted prior to tooth movement. SmartTrackTM achieved significantly higher mean OTM (73.1%) compared to EX30 (42.8%) by Day 14. No difference in OTM occurred from Day 1425. Mixed modeling revealed SmartTrackTM and compliance separately provided 16% and 9% higher OTM. No difference between CBCT measurements and tooth movement was noted. SmartTrackTM achieved a higher mean OTM with a seemingly shorter lag phase compared to the EX30 material over a 25day period. A combination of SmartTrackTM effects and compliance play a c ollective role in achievement optimal OTM.

PAGE 9

9 CHAPTER 1 INTRODUCTION Clear orthodontic aligners are actively sought by the public through its thin and easily adaptable nature 1, ideal aesthetic optical properties, ease of proper hygiene, and comfort of wear2 4. Kusy defined ideal archwires as those with properties of high strength, resilience, formability, are springy, biocompatible, have good springback, good range, and are highly esthetic5. Similar ideals are held for orthodontic treatment utilizing aligners. Although the advent of clear aligner therapy sparked interest within the public to seek orthodontic treatment, initial case studies showed that treatment is successfully achieved in minor to moderate crowding. It has been reported that those patients exhibiting crossbites, a deep bite6 7, an anterior open bite or shallow over bite, and those with periodontal problems may all be treated with clear aligner therapy8. Extraction spaces have been shown to be difficult to close with bodily tooth movement since tipping occurs readily as orthodontic force is placed9 11. Newer treatment st rategies have been able to overcome the drawbacks of aligner therapy by being able to treat complex maloccusions7 12, 13, and integration of aligner therapy with fixed treatment in orthognathic su rgery cases and with functional appliances has been able to achieve orthodontic success1417. The aligners tend to function optimally by producing tooth movem ents in an anterior posterior (AP) direction and improving transverse relationships generally by tipping movements11, 18. More difficult movements, such as controlling root position and t ooth rotations have been aided with the advent of Power Ridges and attachments to facilitate movement 2 7 19. Polyurethane is the main e lement in fabrication of the aligners and can be affected by several variables, including heat and moisture. The

PAGE 10

10 prescribed wear to allow for proper aligner prescription expression is at least a twenty hour interval per day for two weeks2. The majority of tooth movement has been proven to occur within the first week of aligner wear, but controversy still remains as to whether the extra week of aligner usage will aid in fulfilling the prescription of the tray 10 20. Vardimon et al found that the distortion energy, or von Mises strain, during maxillary incisor retraction decreased over a fifteen day period, with the highest at day 1, decreasing at day 2, and then maintaining levels from day 2 to day 15 with no complete relapse to the original level21. Due to the decaying forces, it has been suggested to have patients wear aligners for 24 hours for the first two days per aligner and then intermittently up until day 1521. Baldwin et al. had reported of a clear aligner company suggesting a wear pattern of three weeks for full expression of aligner prescription9. Clinical studies previously conducted have shown labial expansion of incisors to achieve only 38% 61.6% of the full aligner prescription expression20, 2224. According to Kravitz et al, retroclining maxillary incisors is two times more predictable in lingual tipping as opposed to than proclination24. Orthodontic tooth movement tends to occur in three general phases of initial, lag, and postlag phases25. In rat models, Arias and Marquez Orozco 26 had reported that the first four days of OTM tended to be in the initial and lag phases. The transition to the postlag phase may take as long as 20 days to complete27, which is after the two week wear pattern for aligners. To facilitate OTM, the coupling of bone resorption and bone regenerati on are necessary in response to the high orthodontic force placed on teeth2729. Accomplishing tooth movement usually requires 20150g of orthodontic force per tooth 30. Light, continuous forces are generally preferred over heavy forces to prevent

PAGE 11

11 hyalinization of the PDL and unstable bone resorption that may occur with heavy forces, which tends to surpass a capillary blood pressure of 2025 gm/cm2 of root surface. Light forces allow for a proper biologic response and allow for stable bone resorption 27. Alveolar bone height concurrent with root length also greatly influence tooth movement and the position of the tooth center of resistance (CRes). Over time, alv eolar bone levels tend to decrease, thus displacing the CRes to a more apical level 31. Since CRes affects how force applied at the coronal level, moments may be greater if alveolar bone levels are decreased. In 2005, a randomized and controlled clinical trial was conducted at UF to assess the effects of recombinant human r elaxin during OTM with clear aligners of a single anterior incisor over an eight week period 23. Although the results of the study found no significant variance between treatment and control groups, other effects were noted. These effects include a higher rate of OTM during the first week compared to the second week of continuous aligner wear during the twoweek prescription cycle, the absolute expression of the aligners was not achieved, the age of subjects had a positive correlation with OTM, and OTM differed greatly between subjects, which also was echoed in previous studies20. Performance of aligner material influences tooth movement. Studies have shown that a hard versus soft aligner material had no statistically significant difference in outcome of extraction space closure9 11, but it has been sh own that a combination of a hard aligner material and a twoweek interval allows for optimal tooth movement10. As with any aligner, working range and initial insertion force are two of the vital traits in performa nce of the aligner material. Initial insertion force is defined as the force

PAGE 12

12 influencing the movement of the teeth according to the prescription expressed in the aligner upon initial insertion. Patients tend to feel more elevated levels of discomfort withi n the initial days after insertion of the appliance 3 32. Working range of an appliance is the difference between the full amount of force imparted by the appliance at initial acti vation until deactivation. Larger working ranges are favorable due to its decreased discomfort perceived by patients and the force influencing tooth movement is able to work over a larger range of distance. An improved material, called SmartTrackTM, developed for Invisalign treatment compared to the existing EX30 material was shown to be superior in both traits. MSDS information procured from Align Technologies reports the material is made from multilayer aromatic thermoplastic polyurethane, and suggests t he material may show improved flexibility and a longer working range similar to the properties reported of a multistranded archwire5. Multistranded stainless steel wires tend to have high springback, moderately low stiffness33, high range, and a dminister a lower force34, which are properties desired in an aligner35. The improved material imparts a force of 4N, compared to the old material force of 4.5N, and also has a working range of 0.20mm, compared to 0.15mm of the old material. The purpose of this study is to investigate the effect of appliance activation force over time on total tooth movement utilizing a human tooth movement model using the standard material (Material S) and an experimental material (Material E). The benefit of utilizing CBCT imaging will also aid in evaluating the alveolar bone relationship to tooth movement. Since the lag phase may last longer than the 2 week prescribed wear period, a longer investigational period from a twoweek wear pattern to a four week we ar pattern will be evaluated to determine if tray prescription expression can be

PAGE 13

13 enhanced. Tooth movement curvatures will also be evaluated to investigate whether Material E may allow for a more linear phase of tooth movement as opposed to the three defined phases25.

PAGE 14

14 CHAPTER 2 MATERIALS AND METHODS Study Design The basis of the study design is echoed off of previous aligner research20, 23. IRB approval had been obtained to conduct a single center clinical trial at the University of Florida Graduate Orthodontic Clinic. Participating subjects were between and including the ages of 1840, had minor incisor misalignment, and would undergo orthodontic treatment. Five groups of subjects with five to seven participants in each group were randomized to a material (S or E) with a standar d activation schedule of 0.250 mm over a twenty five day study period. Study clinicians were blinded to the aligner material and an equal number of subjects were randomized to each material group. Enrollment and Study Participation Each subject was initially phone screened and then scheduled for the first of two preliminary visits. The inclusion and exclusion criteria are outlined in Table 21 The first visit is the Eligibility Visit, which is to distinguish potential study subjects with minor maxil lary incisor malalignment and to exclude those falling under the exclusion criteria. The following procedures will be performed. The informed consent form, completed medical history, and intraoral clinical examination were completed. Those who are deemed eligible based on this preliminary visit were then allowed to proceed to the Screening Visit. The goal of this visit was to determine if the subject is fully eligible for completion of the study according to the Cadent iTero digital impression scans, which were sent to Align Technology for fabrication of Invisalign appliances, intraoral and extraoral photographs, and a conebeam computed tomography radiograph (CBCT). A CBCT is standard protocol before orthodontic treatment at the University of Florida.

PAGE 15

15 Wom en were required to undergo a urine pregnancy test to ensure a negative reading before any imaging procedures. Those who are deemed eligible for completion of the study had digital impression scans sent to Align Technology for Invisalign appliance fabrication, given a study number, and enrolled in the study. An outline of data collected at each s tudy visit is depicted in Table 2 2 Once a participant was accepted into the study, one central incisor, the right or left, was chosen for activation through th e aligners and termed as the target tooth. The target tooth had to follow proper criteria, such as no adjacent teeth to block tooth movement and must have been able to move a 0.50mm in an AP direction. The maxilla was the only arch receiving an aligner, which was fabricated using either Material S or Material E and had an activation prescription in the anteroposterior (AP) direction of 0.250mm. Instead of utilizing polyvinyl siloxane (PVS) impressions as in previous studies20, 23, digital scans were taken with an iTero optical scan ner for each subject. The iTero optical scanner is reliable in replication of the dentition and an alternative to the conventional PVS impressions36. The single maxillary aligner was delivered on a Monday, and scans were taken on days 1, 2, 3, 4, 7, 9, 11, 14, 16, 18, 21, 23, and 25. The study terminated at day 25, and final data collection was taken. A total of 33 subjects were enrolled in the study after initial screening. If a subject missed more than 2 s tudy visits, they were involuntarily dropped from the study. One subject was dismissed midway through treatment due to the lack of follow up with study visits. Data was utilized from the terminated subject since the last study visit. Subjects were required to wear the aligners full time except for brushing their teeth, drinking, and eating. Compliance with aligner wear was documented through a daily diary distributed

PAGE 16

16 to study subjects at the initial delivery of aligners. A completed medical and dental histo ry was also taken at the initial visit and routinely checked along with the daily diary at every visit to monitor any excessive medication intake. At the end of data collection, study subjects were given the opportunity to be treated at the University of Florida Graduate Orthodontic Clinic for routine orthodontic treatment using the Invisalign appliances. Collection of Data Clinical Tooth Movement The measurement of the AP movement of the target tooth was done using iTero digital impression scans and a Bite Matching algorithm, a proprietary software developed by Align Technologies to superimpose scans more efficiently and effectively. Radiographic Measures Each cone beam radiograph was sliced with a 0.4mm and 3.6mm thickness to include the full length of the target tooth for each subject with accompanying apical bone, making sure to account for the incisive canal. Sliced images were then flattened to an 8bit TIF image, minimizing any compression. ImageJ software was used to magnify the image without ch anging the innate properties of the initial file. A fractal analysis (FA) was conducted to quantify bone by evaluating the organization and complexity of bone structure using the TACT workbench. This analysis was used to qualitatively and quantitatively assess bone in the apical region of the tooth prescribed for movement. A FA is advantageous compared to gray level analysis in that it is independent of projection geometry or exposure parameters. Digital subtraction techniques require multiple images with reproducible projection geometry to yield

PAGE 17

17 meaningful results and is, thus, impractical in the clinical scenario. Independent of other extraneous variables, FA utilizes the range of signal intensities, converts the intensities into a frequency plot in order to plot the intensities to a 2D regression plot. All images were normalized by utilizing a reference image and a 32 by 32 region of interest (ROI) within the apical bone of the target tooth. The FA was conducted for each ROI using a power spectrum method within the Tuned Aperture Computed Tomography (TACT) workbench. Following a 2D fast Fourier transformation (FFT), the log of the magnitude was plotted against the log of frequencies created by the FFT. The slope of the regression line generated the fract al dimension for each specific ROI 37. Measurements of t he target tooth mimic that of previous studies20 and are summari zed in Figure 21 All measurements were done using InVivo Anatomage Software, version 5, and included measurements of tooth length, root length, crown length, crown to root ratio, the distance of the root apex to the buccal plate, and the widest buccolingual dimension of the target tooth at the crest of the alveolus was done at three different timepoints by one researcher (NDP) and averaged. Statist ical Considerations Statistical assessments were able to utilize a parametric analysis due to the normal distribution of the data. The outcomes of interest were to observe tooth movement from baseline to Day 14 and to Day 25. Primary comparisons were done between treatment groups and the outcomes as well as correlations of CBCT measures and the outcomes. Additional variables such as age, gender, and compliance were also taken into consideration. Analyses conducted included twosample t tests and P earson correlation coefficients with a p value less than 0.05 considered statistically significant. With the addition of multiple data points in this study, we had the advantage of using mixed

PAGE 18

18 modeling to test interactions between radiographic measures, material, compliance, gender, age, and tooth movement.

PAGE 19

19 Table 21. Outline of inclusion and exclusion criter ia. Inclusion criteria 1. Males or females between and including the ages of 18 and 40 years old, desiring correction of minor incisor malalignment using the Invisalign appliance. Subjects may have had previous orthodontic treatment. 2. Adult dentition with all upper anterior teeth present. 3. At least one maxillary central incisor that has sufficient space between it and adjacent teeth to allow AP movement of 0.5mm (crown tipping only). 4. Normal pulp vitality and healthy periodontal tissues as determined by intraoral exam. 5. Good health as determined by medical history. 6. Willingness and ability to comply with study procedures, attend study visits, and complete the study. 7. The ability to understand and sign a written informed consent form, which must be signed pri or to initiation of the study procedures. Exclusion Criteria 1. Significant periodontal disease (>3mm pocket depth or >1mm of recession on maxillary anterior teeth). 2. Active dental disease not under care of either a dentist or periodontist. 3. Chronic daily use of any nonsteroidal anti inflammatory medication, estrogen, calcitonin, or corticosteroids. 4. History of use or current use of any bisphosphonate medication or other medication for treatment of osteoporosis. 5. Current smoker (must not have sm oked in the last six months). 6. Fibroblast function is necessary for proper conservation of periodontal structures. Nicotine has been shown to be destructive to periodontal elements such as periodontal ligament fibroblast growth in a dose dependent manner and can inhibit cell proliferation and diminish protein synthesis58. Tobacco products may also be a major factor in the development of periodontal disease. 7. Women must not be pregnant. Negative urine pregnancy tests prior to exposure to cone beam computed tomography (CBCT) imaging is require to verify pregnancy status. Dental x ray exposure with pregnant women has been questioned in potential associat ion to pituitary and thyroid disorders and low birth weight in infants59. 8. Any condition or use of medication which in the opinion of the investigator interferes with the biology of tooth movement. 9. Any condition which in opinion of the investigator results in increased risk to the subject.

PAGE 20

20 Table 22. Schedule of Study Events Event Prelim 1 Prelim 2 Day 0 Days 1, 2, 3, 4, 7, 9, 11, 14, 16, 18, 21, 23 Day 25 Informed Consent 1 X Inclusion/Exclusion X X Medical History X Pregnancy Test X Intraoral Exam X X X X Maxillary occlusal and frontal photos X X X Cadent iTero digital impression scan X X X Intraoral photos (complete set) X Extraoral photos X Cone beam imaging 2,3 X Dispense aligners and daily diary X Collect aligners and daily diary X Begin planned orthodontic treatment X 1Informed consent must be given before any subject can progress further within the study. 2Cone beam imaging is a usual protocol for orthodontic treatment at the University of Florida. 3Women will be required to take urine pregnancy tests immediately prior to exposure to verify they are not pregnant.

PAGE 21

21 Tooth Length Measured from incisal tip to apex of the target tooth Crown Length Measured from incisal tip perpendicular to a line connecting the buccal and lingual cortical plates. Root Length Measured from a line connecting the buccal and lingual cortical plates to the root apex. Crown to root ratio The division of the crown length into the root length. Distance from apex to buccal cortical plate The measurement of the perpendicular distance from the apex to the buccal cortical plate Widest buccolingual width of tooth at crest of alveolus The measurement of the buccolingual thickness of the tooth at the alveolar crest. Figure 21. Overview of radiographic measurements of the target tooth.

PAGE 22

22 CHAPTER 3 RESULTS An outline of the subject demographic in f ormation is displayed in Table 31 and Table 32 An equal number of males (48.48%) and females (51.52%) participated in this study with an average age of 26.95 ( 5.31) years. Orthodontic tooth movement between materials was stati stically significant at Day 14 (p=0.02) and Day 25 (p=0.02), and values are depicted in Table 3 3 Material E was able to achieve a higher average percentage of tooth movement at Day 14 (73.06%) and Day 25 (77.38%) compared to Material S (42.75% and 50.07%, respectively). A diagrammatic representation of the average amount of tooth movement achieved at all time points between the materials is displayed in Figure 3 1 The term Diff2514 is defined as the percentage of tooth movement achieved at Day 14 subtracted from the percentage of tooth movement achieved at Day 25 to evaluate tooth movement between th e time points. No significant difference was noted in tooth movement between the materials and over time from Day 14 to Day 25 (p=0.18). In comparing a twoweek aligner protocol versus a four week aligner protocol, no difference was noted (p=0.23) in tooth movement achieved between Day 14 and Day 25. Material S noted 9.73% of tooth movement from Day 14 to Day 25, as defined by the Diff3514 variable, while Material E was 0.47%, thus showing that the majority of tooth movement was achieved by Day 14 with M aterial E while Material S still allowed for a residual amount tooth movement to occur past Day 14. Average percentage of tooth movement in relation to age was not significant at Day 14 (r= 0.05, p=0.78), Day 25 (r= 0.03, p=0.86), or time points in between (r= 0.08, p=0.67).

PAGE 23

23 Compliance between the materials at Day 14 and Day 25 showed no significant differences in the average number of hours of reported aligner wear (p=0.65; p=0.61) as shown in Table 34 Thus, compliance was similar between the materials with accompanying similar maximum and minimum hours of wear. Table 3 5 shows 10 subjects had of average tooth movement achieved at Day 14, and 9 out of those 10 subjects were assigned to Material E. Table 36 shows that of those 10 subjects, the ho urs of compliance were slightly higher than the other percentage groups. Thus, slightly higher compliance may point towards higher amounts of tooth movement. Gender and tooth movement is depicted in Table 3 7 No significant relationship can be seen in tooth movement between the genders at Day 14 (p=0.39), Day 25 (p=0.65), and time points in between (p=0.69). Females and males had higher average percentages of tooth movement with Material E than Material S, as seen in Figure 3 2 Males tended to have higher percentages of tooth movement than women at all time points of average percentages of tooth movement. Radiographic measures had no significant relationships to tooth movement as displayed in Table 1 8 Marginal significance was noted with tooth length in relation to tooth movement achieved at Day 14 (r=0.33, p=0.07) and Day 25 (r=0.31, p=0.09), and root length had marginal significance at Day 14 (r=0.33, p=0.07). Mixed model analyses between all variables noted significant interactions between tooth movem ent with compliance (p=0.0001) and Material E (p=0.0017). Overall average tooth movement in millimeters between the materials is displayed in Figure 3 3. The average tooth movement achieved at Day 14 and Day 25

PAGE 24

24 with Material S is similar to the previous st udies done at the University of Florida20, 22, 23. Material E outperformed the previous studies at each time point. Table 31 Demographics of subjects Variable N Material E Material S P Value Total 33 17 16 p=0.87 (NS) Females 17 9 8 Males 16 8 8 Table 32 Age of subjects N Mean (yrs) SD Min (yrs) Max (yrs) P Value Total 33 26.95 5.31 20.06 40.07 p=0.74 (NS) Material E 17 26.65 5.44 22.05 40.07 Material S 16 27.72 5.32 20.06 38.08 Table 33 Material differences in average percent of tooth movement at Day 14 (Pct14), Day 25 (Pct25), and time points in between (Diff3514) Variable N Mean SD Min Max P Value Material E Pct 14 16 73.06% 37.98% -18.00% 133.00% Pct 14 p=0.02** Pct 25 p=0.02** Diff2514 p=0.18 (NS) Pct 25 16 77.38% 30.36% 17.00% 130.00% Diff2514 15 0.47% 19.96% 35.00% 39.00% Material S Pct 14 16 42.75% 30.93% -31.00% 103.00% Pct 25 15 50.07% 31.06% 4.00% 120.00% Diff2514 15 9.73% 20.62% 27.00% 42.00% Table 34 Material differences in average compliance on Day 14 and Day 25. Variable Mean (hrs) SD (hrs) Min (hrs) Max (hrs) P Value Material E Meanwear 14 21.40 1.73 15.89 22.81 Meanwear 14 p=0.65 (NS) Meanwear 25 p=0.61 (NS) Meanwear 25 21.44 1.36 17.69 22.84 Material S Meanwear 14 21.17 0.87 19.39 22.42 Meanwear 25 21.21 0.99 18.74 22.63

PAGE 25

25 Table 35 Average percent of tooth movement achieved between the materials and subject composition of movement groups. Percentage of Tooth Movement Achieved at Day 14 Material E (N) Material S (N) Total (N) 2 7 9 36 79% 5 8 13 9 1 10 Table 36 Average percent of tooth movement achieved and average compliance scores for accompanying percentage groups. Percentage of Tooth Movement Achieved at Day 14 Mean (hrs) SD Min (hrs) Max (hrs) Mean Wear 14 20.76 0.84 19.39 22.10 36 79% 20.90 1.68 15.89 22.42 22.21 0.63 20.89 22.81 Table 37 Differences in average tooth movement achieved between genders Variable Mean SD Min Max P Value Females Pct 14 52.1% 42.5% -31.0 119.0 Pct 14 p=0.39 (NS) Pct 25 p=0.65 (NS) Diff2514 p=0.69 (NS) Pct 25 61.3% 36.7% 4.0% 108.0% Diff2514 6.3% 21.6% -35.0% 39.0% Males Pct 14 63.7% 31.8% 20.0% 133.0% Pct 25 66.9% 30.6% 9.0% 130.0% Diff2514 3.2% 20.3% -35.0% 42.0%

PAGE 26

26 Table 38 Comparison of CBCT Measures and Tooth Movement at Day 14 (Pct 14) and Day 25 (Pct 25) Variable Mean SD Pct 14 P Value Pct 25 P Value Tooth Length 23.66mm 1.45mm 0.07 0.09 Crown Length 11.93mm 0.81mm 0.66 0.49 Root Length 11.35mm 2.38mm 0.07 0.12 Crown to Root Ratio 1.03 0.13 0.20 0.24 Fractal Analysis 1.83 0.32 0.78 0.80 Distance from apex to buccal cortical plate 2.40mm 1.19mm 0.21 0.16 Widest Buccolingual Width of Tooth at Crest of Alveolus 6.63mm 1.57mm 0.89 0.62 Figure 31 Tooth movement (in mm) by material over the 25day study period. Tooth Movement Achieved (mm)

PAGE 27

27 Figure 3 2 Tooth movement by gender and material over 25 days. Figure 3 3 Overall tooth movement between previous UF studies and the current study by material Tooth Movement Achieved (%) Tooth Movement Achieved (%)

PAGE 28

28 CHAPTER 4 DISCUSSION Orthodontic tooth movement (OTM) is the product of intricate cellular mechanisms. These delicate mechanisms are the foundation of which exogenous pharmacologic influences, endogenous influences, and vitamin supplements tend to affect the rate of OTM. Studi es have shown that the exogenous use of estrogen, bisphosphonates, corticosteroids, and nonsteroidal anti inflammatory drugs can affect the rate of OTM26, 3840. As orthodontic treatment begins, discomfort may ensue, resulting in patients reaching for pain relief medications. Miller et al.3 compared a fixed appliance treatment group to an Invisalign treatm ent group and has shown that at every time point over a 7day period, Invisalign treatment was perceived as more comfortable and m anageable than fixed treatment. Although both treatment groups experienced a decrease in quality of life at the beginning of treatment, the quality of life scores for those undergoing fixed appliance treatment decreased as treatment progressed and experien ced decreases in various aspects of their daily lives. Analgesic usage was highest among the fixed appliance subjects, but became insignificant after the third day3. Shalish et al. compared a lingual fixed treatment group, buccal fixed treatment group, and an Invisalign treatment group and reported 0% of analgesic usage among Invisalign subjects by the 6th day of treatment32. The lingual and buccal fixed treatment groups on average were not able to completely recover from initial declines in food consumption until the 5th10th day of treatment, while the Invisalign treatment subjects had recovered by the 4th day at most32. Although this study did not specifically track analgesic usage over the 25day experimental period, the effec ts of an analgesic may

PAGE 29

29 not have had a significant effect on tooth movement since the amount of tooth movement achieved is similar to previous studies20, 22, 23. Tooth movement with clear al igners over a 14day period has been shown to produce less than 100% of prescription expression20, 2224. The results found in this study tend to echo similar sentiments As the data shows, tooth movement over a 14day period provides a similar amount of tooth movement as a 25day period. This is the first study to take such minute time points, which proved that tooth movement with clear aligners still follows the three ph ases previously described25, but the SmartTrackTM material possibly exhibits a short lag phase of 23 days and completes the majority of tooth movement by the 14thday of wear. The SmartTrackTM material also proved to achieve a higher mean percentage of tooth movement at Day 14 and Day 25, which was significantly higher than the standard EX30 material. When aligners are worn, there are short term and longterm forces involved. Short term forces are when an ali gner is fitted initially in the mouth and longterm forces are after initial fitting of aligner, forces are placed on teeth through the prescription in the tray and occlusal loading35, 41. Modes of def ormation pertinent to aligners are tension, bending, and torsion. The elastic property of aligners allow the aligners to adapt to the prescribed movement when strain occurs in the aligners, but the viscoelastic property of aligners causes the fatigue of force over time. Longterm moisture exposure of 48 hours may affect align er performance after strain placement and tensile properties tend to decrease35. Stress relaxation of the aligner decreases the ability of the material to produce the appropriate amoun t of force for an appropriate amount of tooth movement42. Mimicking of an intraoral environment in a water bath of 37.0oC and

PAGE 30

30 placement of 5% strain upon thermoplastic material has shown to quicken the stress relaxation of the material. Fu rthermore, only about 42.366.6% of the initial forces was delivered after the immersion in the water bath42. As thermoplastic polyurethane materials age, a process called plasticization occurs in which water is absorbed as the material rel axes. The absorption of water may play a role in the breakup of Hydrogen bonds present within the composition of the material, and the hygroscopic expansion of the material may possibly accelerate further degradation43. A study by Ryokawa et al. compared the Invisalign EX30 material to various other thermoplastic materials by submerging the material in a distilled water bath at 37.0oC and reported the highest water absorption by the Invisalign material after 24 hours and 336 hours of immersion44. This may be due to the amorphous polymer composition, allowing for more free space to be utilized by the water absorption. It is interesting to note that the Invisalign material did not have the highest hygroscopic expansion rate when compared to other thermoplastic materials after immersion in the water bath, possibly due to previous water absorption and hygroscopic expansion at room temperature44. This combina tion of water absorption and the temperature of the oral cavity may play a role in the continued degradation of the aligner material43. The oral cavity exhibits a more complicated nature and temperature differences and the intermittent pressures plac ed on the teeth with aligner removal and reinsertion may also play an additive role in the fatigue of force levels. As temperatures rise, the amount of water absorption also increases43 and oxidation of methylene diphenylene units within the composition of the thermoplastic polyurethane material can lead to degradation of the elastic properties45. With a plastic device in the oral cavity, the use of Invisalign appliances has been shown

PAGE 31

31 to be chemically stable46 and not induce any cytotoxic effects on human gingival fibroblasts and lack any estrogenic effects of the material eluents47. A noticeable amount of wear has been proven evident in the aligners after the recommended two week interval. Calcification, distortion, cracking, and development of biofilms within the aligner material have been shown46, 48, 49. Plaque accumulation may interfere with the surface contour of the aligner50. Buccal aspects of worn appliances have also shown an increase in hardness from mastication induced cold working 49. A randomized and controll ed clinical trial performed at UF in 200920 studied the eff ects and efficiency of OTM by inserting a fresh aligner after one week of wear, replacing the worn aligner. The results showed that there is no added benefit of placing a fresh aligner with the same prescription after one week of wear instead of utilizing the same aligner for the two week period. This finding suggests that material fatigue and deactivation is not the ratelimiting factor in the event of tooth movement. In terms of force application, the SmartTrackTM material imparts an overall force of 4.0 N to the maxillary incisor, but studies have shown that even a 1.80N (183.5g) force with a SentalloyTM wire for intrusion or extrusion of a single tooth may be too high and may contribute to root resorption over a 4 week period51. Although there is no scientific evidence of specific numeric force values necessary for tooth movement52, the force levels of thermoplastic appliances with an activation of 0.50mm may range from 2.91N to 5.10N24, 53. A recent study showed that a lower aligner activation of 0.50mm tended to impart a higher level of force than a 1.0mm activation, and thinner aligner materials delivered lower forces overal l than thicker materials53. The higher force level of the lower activation may be due to possible slippage of the material from the tooth

PAGE 32

32 due to a high activation distance. Invisalign utilizes a thin material of 0.30 inches, which is easily adaptable in the mouth and cause minimal posterior intrusion1. The high forces imparted upon the teeth from clear aligners may dissipate through stretching of the aligner material from repeated removal and insertion thus reducing the high impact of the overall force. Although Invisalign may use a higher force range than usual fixed appliance therapy, root resorption is usually not a cause for concern for treatment with Invisalign appliances54. Recent data shows that 100 consecutively treated Invisalign patients had little to no root resorption. On the other hand, 10% of patients treated with fixed appliances had root resorption of at least 3mm7. Our findings have shown that a lower activation of 0.25mm with a low initial insertion force and longer working range with the new SmartTrackTM material were able to achieve a higher average percentage of tooth m ovement achieved than previous studies with 0.50mm of activation per aligner after 14 days20, 23. Tipping within the periodontal ligament (PDL) space was achieved during the initial phase since the PDL space is generally 0.150.20mm55 from Day 0 Day 2, and the lag phase of tooth movement seemed to be limited to Day 2 to Day 4. This finding suggests that the low er millimeter activation coupled with a more adaptable material may have imparted a much more operational force on the incisor compared to higher millimeter activation with the standard material. Since proclination of maxillary incisors is a difficult movement compared to retroclination24, overcorrection of maxillary buccal tipping movements may aid in achieving the desired measurement1. As previous studies have shown3 20, 22, 23, 32, a larger percentage of female subjects partook in Invisalign studies, but this study had an approximately equal

PAGE 33

33 distribution of males and females. No difference in the average percent of tooth movement achieved was noted between age groups or genders, compared to In evaluating the data, some subjects were able to experience more than 100% of tooth movement prescribed. Occlusal factors and lack of intra arch contacts were analyzed and found that even those patients with a proximal contact in place, tooth movement may be affects by the opposing occlusion. Although it has been found that intra and inter arch contacts may negatively affect tooth movement56, the opposite situation may ha ve been shown in this study with the added effect of the lower anterior occlusion affecting the excessive positive outcome of the maxillary incisor AP movement. Future studies investigating tooth movement with clear aligners may include the use of cyclical force devices, local delivery of exogenous molecules such as inflammatory cytokine IL1 for stimulation of osteoclasts, and low level laser therapy57. Animal studies conducted so far show promising results, but human clinical trials with defined methods and durations are necessary to help implement a proper treatment protocol to achieve exceptional tooth movement in an efficient and effective manner.

PAGE 34

34 CHAPTER 5 CONCLUSIONS The SmartTrackTM material with a lower initial insertion force and a longer working range had an increased mean percentage of tooth mov ement compared to the standard EX30 Invisalign material. The SmartTrackTM material was more effective at tooth movement over a 14day span than the EX30 material, but the amount of average residual tooth movement from Day 14 to Day 25 between the material s is not statistically significant. A higher percentage of tooth movement was achieved over a 25day period compared to a 14day period, but this difference is not statically significant. Initial decrease of strain in the SmartTrackTM aligner may deliver a more physiologic force on the maxillary incisor to allow for more optimal tooth movement. No statistical difference was noted between tooth movement and gender, age, or CBCT measurements. Our study echoed previous studies, showing that 100% of aligner pre scription was not achieved. The SmartTrackTM material had a higher mean percentage of tooth movement at Day 14 and Day 25 compared to previous studies done at UF. Orthodontic tooth movement still follows the three phases of tooth movement, even with a decr ease in initial insertion force and an increase in working range.

PAGE 35

35 LIST OF REFERENCES 1. Vlaskalic V, Boyd R. Clinical evoluation of the Invisalign appliance. J Calif Dent Assoc 2002;30(10):76976. 2. Joffe L. Invisalign: early experiences. J Orthod 2003;30(4):34852. 3. Miller KB, McGorray SP, Womack R, Quintero JC, Perelmuter M, Gibson J, et al. A comparison of treatment impacts between Invisalign aligner and fixed appliance therapy during the first week of treatment. Am J Orth od Dentofacial Orthop 2007;131(3):302 e19. 4. Chenin DA, Trosien AH, Fong PF, Miller RA, Lee RS. Orthodontic treatment with a series of removable appliances. J Am Dent Assoc 2003;134(9):12329. 5. Kusy RP. A review of contemporary archwires: their propert ies and characteristics. Angle Orthod 1997;67(3):197207. 6. Giancotti A, Mampieri G, Greco M. Correction of deep bite in adults using the Invisalign system. J Clin Orthod 2008;42(12):71926; quiz 28. 7. Boyd RL. Complex orthodontic treatment using a new protocol for the Invisalign appliance. J Clin Orthod 2007;41(9):52547; quiz 23. 8. Wheeler TT. Invisalign material studies. Am J Orthod Dentofacial Orthop 2004;125(3):19A. 9. Baldwin DK, King G, Ramsay DS, Huang G, Bollen A M. Activation time and material stiffness of sequential removable orthodontic appliances. Part 3: Premolar extraction patients. American Journal of Orthodontics and Dentofacial Orthopedics 2008;133(6):83745. 10. Bollen A M, Huang G, King G, Hujoel P, Ma T. Activation time and material stiffness of sequential removable orthodontic appliances. Part 1: Ability to complete treatment. American Journal of Orthodontics and Dentofacial Orthopedics 2003;124(5):496501. 11. Clements KM, Bollen AM, Huang G, King G, Hujoel P, Ma T. Activation time and material stiffness of sequential removable orthodontic appliances. Part 2: Dental improvements. Am J Orthod Dentofacial Orthop 2003;124:502 8. 12. Boyd RL. Esthetic orthodontic treatment using the invisalign appliance for moderate to complex malocclusions. J Dent Educ 2008;72(8):94867. 13. Giancotti A, Di Girolamo R. Treatment of severe maxillary crowding using Invisalign and fixed appliances. J Clin Orthod 2009;43(9):5839; quiz 82.

PAGE 36

36 14. Eckhart JE. Sequential MARA Invisalign treatment. J Clin Orthod 2009;43(7):43948; quiz 59. 15. Boyd RL. Surgical orthodontic treatment of two skeletal Class III patients with Invisalign and fixed appliances. J Clin Orthod 2005;39(4):24558. 16. Womack WR, Day RH. Surgical orthodontic treatment using the Invisalign system. J Clin Orthod 2008;42(4):23745. 17. Marcuzzi E, Galassini G, Procopio O, Castaldo A, Contardo L. Surgical Invisalign treatment of a patient with Class III malocclusion and multiple missing teeth. J Clin Orthod 2010;44(6):37784. 18. Crosby D, Lee J. A patient classification system for Invisalign cases. J Clin Orthod 2009;43(8):5026. 19. Castroflorio T, Garino F, Lazzaro A, Debernardi C. Upper incisor root control with Invisalign appliances. J Clin Orthod 2013;47(6):34651; quiz 87. 20. Drake CT, M cGorray SP, Dolce C, Nair M, Wheeler TT. Orthodontic tooth movement with clear aligners. ISRN Dent 2012;2012:657973. 21. Vardimon AD, Robbins D, Brosh T. In vivo von Mises strains during Invisalign treatment. American Journal of Orthodontics and Dentofacial Orthopedics 2010;138(4):399409. 22. McGorray SP, Chisari JR, Wheeler TT. Variables affecting orthodontic tooth movement with clear aligners. Am J Orthod Dentofacial Orthop. 23. McGorray SP, Dolce C, Kramer S, Stewart D, Wheeler TT. A randomized, placebocontrolled clinical trial on the effects of recombinant human relaxin on tooth movement and short term stability. Am J Orthod Dentofacial Orthop 2012;141(2):196203. 24. Kravitz ND, Kusnoto B, BeGole E, Obrez A, Agran B. How well does Invisalign work? A prospective clinical study evaluating the efficacy of tooth movement with Invisalign. Am J Orthod Dentofacial Orthop 2009;135(1):27 35. 25. Roberts Harry D, Sandy J. Orthodontics. Part 9: anchorage control and distal movement. Br Dent J 2004;196(5):25563. 26. Arias OR, Marquez Orozco MC. Aspirin, acetaminophen, and ibuprofen: their effects on orthodontic tooth movement. Am J Orthod Dentofacial Orthop 2006;130(3):36470. 27. Krishnan V, Davidovitch Z. Cellular, molecular, and tissuelevel reactions to orthodontic force. Am J Orthod Dentofacial Orthop 2006;129(4):469 e132.

PAGE 37

37 28. Toms SR, Lemons JE, Bartolucci AA, Eberhardt AW. Nonlinear stress strain behavior of periodontal ligament under orthodontic loading. American Journal of Orthodontics and Dentofacial Ort hopedics 2002;122(2):17479. 29. Baloul SS, Gerstenfeld LC, Morgan EF, Carvalho RS, Van Dyke TE, Kantarci A. Mechanism of action and morphologic changes in the alveolar bone in response to selective alveolar decortication facilitated tooth movement. Am J Orthod Dentofacial Orthop 2011;139(4 Suppl):S83101. 30. Mao JJ, Wang X, Kopher RA. Biomechanics of craniofacial sutures: orthopedic implications. Angle Orthod 2003;73(2):12835. 31. Burstone CJ, Pryputniewicz RJ. Holographic determination of centers of rotation produced by orthodontic forces. Am J Orthod 1980;77(4):396409. 32. Shalish M, Cooper Kazaz R, Ivgi I, Canetti L, Tsur B, Bachar E, et al. Adult patients' adjustability to orthodontic appliances. Part I: a comparison between Labial, Lingual, and Inv isalign. Eur J Orthod 2012;34(6):72430. 33. Kapila S, Sachdeva R. Mechanical properties and clinical applications of orthodontic wires. Am J Orthod Dentofacial Orthop 1989;96:1009. 34. Kusy RP, Dilley GJ. Elastic property ratios of a triplestranded stai nless steel arch wire. American Journal of Orthodontics 1984;86(5):17788. 35. Tricca R, Li C. Properties of aligner material Ex30. In: OC. T, editor. The invisalign system. Philadelphia: Quintessence; 2006. p. 17786. 36. Garino F, Garino B. The iOC intra oral scanner and Invisalign: a new paradigm. J Clin Orthod 2012;46(2):11521; quiz 24. 37. Nair MK, Seyedain A, Webber RL, Nair UP, Piesco NP, Agarwal S, et al. Fractal analyses of osseous healing using tuned aperture computed tomography images. Eur Radiol 2001;11(8):15105. 38. Bartzela T, Turp JC, Motschall E, Maltha JC. Medication effects on the rate of orthodontic tooth movement: a systematic literature review. Am J Orthod Dentofacial Orthop 2009;135(1):1626. 39. Fujimura Y, Kitaura H, Yoshimatsu M, Eg uchi T, Kohara H, Morita Y, et al. Influence of bisphosphonates on orthodontic tooth movement in mice. The European Journal of Orthodontics 2009;31(6):57277. 40. Kalia S, Melsen B, Verna C. Tissue reaction to orthodontic tooth movement in acute and chroni c corticosteroid treatment. Orthod Craniofac Res 2004;7(1):2634.

PAGE 38

38 41. Zhang N, Bai Y, Ding X, Zhang Y. Preparation and characterization of thermoplastic materials for invisible orthodontics. Dental Materials Journal 2011;30(6):95459. 42. Fang D, Zhang N, Chen H, Bai Y. Dynamic stress relaxation of orthodontic thermoplastic materials in a simulated oral environment. Dental Materials Journal 2013;32(6):94651. 43. Boubakri A, Haddar N, Elleuch K, Bienvenu Y. Impact of aging conditions on mechanical properties of thermoplastic polyurethane. Materials & Design 2010;31(9):4194201. 44. Ryokawa H, Miyazaki Y, Fujishima A, Miyazaki T, Maki K. The mechanical properties of dental thermoplastic materials in a simulated intraoral environment. Orthodontic Waves 2006;65(2):64 72. 45. Servay T, Voelkel R, Schmiedberger H, Lehmann S. Thermal oxidation of methylene diphenylene unit in MDI TPU. Polymer 2000;41(14):524756. 46. Gracco A, Mazzoli A, Favoni O, Conti C, Ferraris P, Tosi G, et al. Short term chemical and physical changes in invisalign appliances. Aust Orthod J 2009;25(1):3440. 47. Eliades T, Pratsinis H, Athanasiou AE, Eliades G, Kletsas D. Cytotoxicity and estrogenicity of Invisalign appliances. American Journal of Orthodontics and Dentofacial Orthopedics 2009;136(1):10003. 48. Low B, Lee W, Seneviratne CJ, Samaranayake LP, Hagg U. Ultrastructure and morphology of biofilms on thermoplastic orthodontic appliances in 'fast' and 'slow' plaque formers. Eur J Orthod 2011;33(5):57783. 49. Schuster S, Eliades G, Zinel is S, Eliades T, Bradley TG. Structural conformation and leaching from in vitro aged and retrieved Invisalign appliances. American Journal of Orthodontics and Dentofacial Orthopedics 2004;126(6):72528. 50. Eliades T, Bourauel C. Intraoral aging of orthodontic materials: The picture we miss and its clinical relevance. American Journal of Orthodontics and Dentofacial Orthopedics 2005;127(4):40312. 51. Fuck L M, Drescher D. Force Systems in the Initial Phase of Orthodontic Treatment a Comparison of Different Leveling Archwires. Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopdie 2006;67(1):618. 52. Ren Y, Maltha JC, Kuijpers Jagtman AM. Optimum force magnitude for orthodontic tooth movement: a systematic literature review. Angle Orthod 2003; 73(1):8692.

PAGE 39

39 53. Kohda N, Iijima M, Muguruma T, Brantley WA, Ahluwalia KS, Mizoguchi I. Effects of mechanical properties of thermoplastic materials on the initial force of thermoplastic appliances. Angle Orthod 2013;83(3):476 83. 54. Brezniak N, Wasserstei n A. Root resorption following treatment with aligners. Angle Orthod 2008;78(6):111924. 55. Wolf HF, Rateitschak KH. Periodontology: Thieme; 2005. 56. Dudic A, Giannopoulou C, Kiliaridis S. Factors related to the rate of orthodontically induced tooth movement. Am J Orthod Dentofacial Orthop 2013;143(5):61621. 57. Nimeri G, Kau CH, Abou Kheir NS, Corona R. Acceleration of tooth movement during orthodontic treatment a frontier in Orthodontics. Prog Orthod 2013;14(42). 58. Chang YC, Huang FM, Tai KW, Yang LC, Chou MY. Mechanisms of cytotoxicity of nicotine in human periodontal ligament fibroblast cultures in vitro. J Periodontal Res 2002;37(4):27985. 59. Ludlow JB, Ivanovic M. Comparative dosimetry of dental CBCT devices and 64slice CT for oral and maxill ofacial radiology. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 2008;106(1):10614.

PAGE 40

40 BIOGRAPHICAL SKETCH Neha D. Patel was born in Chicago, Illinois to Doctors Dipak and Neela Shah. Her fath er is an i nterventional r adiologi st and her mother is a retired p ediatric d entist. Neha has one sibling, Akash Shah, wh o is a dual fellowship trained r adiologist. Nehas family moved from Chicago to Galesburg and finally to Moline, Illinois, where the rest of her childhood was spent. Upon graduation from Moline Senior High School, Neha attended the University of Illinois at Urbana Champaign and received a BS in p sychology. After her undergraduate training, Neha was awarded her DDS at the Uni versity of Michigan in Ann Arbor, Michigan. Fresh from dental school, Neha applied for residency in o rthodontics and matched at the University of Florida. After her first year of residency, Neha was married in Moline, Illinois to Pratik S. Patel. In May of 2014, Neha will graduate from the University of Florida with a certificate in o rthodontics and a Master of Science Neha and her husband will move to Indianapolis, Indiana in June of 2014 to begin their lives together. Neha is a member of the Omicron Kappa Upsilon dental honor fraternity, Delta Sigma Delta dental fraternity, The National Scholars Honor Society, and Phi Kappa Phi. During her dental training, she was given the International College of Dentists Award, Comprehensive Care Award, and Russell W. Bunting Award in Periodontics. Neha has published one article in the Journal of Public Health Dentistry, titled Pediatric patients' orthodontic treatment need, quality of life, and smiling patterns an analysis of patient, parent, and pr ovider responses Neha has many hobbies, including travelling, rock climbing, running, baking, and Indian classical dancing.


xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID E1OZX83DD_1MOP5S INGEST_TIME 2014-10-03T22:15:45Z PACKAGE UFE0046725_00001
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES