Virtual bracket removal: a comparative assessment of different software packages.

BACKGROUND: High precision intra-oral scans, coupled with advanced software, enable virtual bracket removal (VBR) from digital models. VBR allows the delivery of retainers and clear aligners promptly following debonding, thus reducing the patients' appointments and minimizing the likelihood of tooth movement. The objective of this study was to compare the enamel surface before bonding and after VBR using three different Computer-aided design (CAD) software and to compare their accuracy. METHODS: Maxillary scans of 20 participants starting orthodontic treatment were selected for inclusion in the study, who exhibited mild to moderate crowding and required bonding of brackets on the labial surface of permanent maxillary teeth (from the maxillary left first molar to the maxillary right first molar). Two intra-oral scans were conducted on the same day, before bonding and immediately after bonding using CEREC Omnicam (Sirona Dental Systems, Bensheim, Germany). The virtual removal of the brackets from the post-bonding models was performed using OrthoAnalyzer (3Shape, Copenhagen, Denmark), Meshmixer (Autodesk, San Rafael, Calif, USA), and EasyRx (LLC, Atlanta, GA, USA) software. The models that underwent VBR were superimposed on the pre-bonding models by Medit Link App (Medit, Seoul, South Korea) using surface-based registration. The changes in the enamel surface following VBR using the three software packages were quantified using the Medit Link App. RESULTS: There was a significant difference among the 3Shape, Meshmixer, and EasyRx software in tooth surface change following VBR. Specifically, EasyRx exhibited lower levels of accuracy compared to the other two VBR software programs (p<.001, p<.001). A significant difference in enamel surface change was observed between tooth segments across all software groups, in both incisors and molars, with VBR of the molars exhibiting the lowest level of accuracy (3Shape p=.002, Meshmixer p<.001, EasyRx p<.001). Regarding the direction of tooth surface changes following VBR, it was observed that all three groups exhibited a significant increase in the percentage of inadequate bracket removal across all teeth segments. CONCLUSIONS: 3Shape and Meshmixer manual VBR software were found to be more accurate than EasyRx automated software, however, the differences were minimal and clinically insignificant.

Airway dimensional changes following bone anchored maxillary protraction: a systematic review.

BACKGROUND: The introduction of skeletal anchorage utilized for maxillary protraction with a face mask or class III elastics has been developed for the management of class III malocclusions with minimal dental effect. The objective of the present review was to evaluate the current evidence regarding airway dimensional changes following bone-anchored maxillary protraction. A search was conducted by two authors (S.A & B.A) in the following databases: MEDLINE via PubMed, Cochrane Library, Web of Science, Scopus, Google Scholar and Open Grey; besides a hand search in references of selected articles and developing a search alert in electronic databases. Selection criteria comprised randomized as well as prospective clinical trials evaluating airway dimensional changes following bone-anchored maxillary protraction. Relevant data were extracted after studies retrieval and selection. The risk of bias was thereafter evaluated using the revised RoB 2 tool for randomized clinical trials and the ROBINS-I tool was used for non-randomized clinical trials. The quality of studies was assessed using the modified Jadad score. After examining (eligibility) full-text articles, four clinical trials were ultimately included. These studies evaluated the airway dimensional changes, following bone-anchored maxillary protraction in comparison to different control study groups. Based on the available evidence, all the bone-anchored maxillary protraction devices used in the eligible studies in the present systematic review resulted in an improvement in the airway dimensions. However, due to the few numbers of studies available and the guarded evidence due to the low quality of evidence of three out of four included articles, there is no strong evidence to support a significant increase in the airway dimensions following bone-anchored maxillary protraction. Therefore, there is a need for more randomized controlled clinical trials with similar bone-anchored protraction devices and similar assessment methods for more valid comparisons, excluding any confounding factors, on airway dimensional changes.

Altering calcium and phosphorus supplementation in pregnancy and lactation affects offspring craniofacial morphology in a sex-specific pattern.

INTRODUCTION: The effects on offspring craniofacial bone morphology and accretion because of altered maternal exposure to dietary components such as calcium (Ca) and phosphorus (P) are unclear. The objective of this study was to investigate the changes in offspring skull morphology and tissue mineral density (TMD), including sex-specific changes, with exposure to a maternal diet high in Ca-to-P levels during gestation and lactation in mice. METHODS: Time-mated FVB wild-type mice were fed a normal or experimental diet during gestation until weaning. The experimental diet contained a 3-fold increase in Ca and a 3-fold decrease in P (Ca:P molar ratio, 10.5) compared with normal mouse chow (Ca:P molar ratio, 1.5). The heads of 6-week-old control and experimental offspring mice were collected and scanned using microcomputed tomography. Three-dimensional geometric morphometric analysis was performed to analyze changes in craniofacial morphology. TMD measurements were also analyzed. RESULTS: We observed subtle changes and no significant differences between offspring control and experimental skulls when we compared all samples. However, when we separated skulls by sex, we discovered significant differences in craniofacial morphology and TMD. Experimental female offspring possessed skulls that were smaller, narrower transversely, taller vertically, and decreased in TMD. Experimental male offspring possessed skulls that were larger, wider transversely, shorter vertically, and increased in TMD. CONCLUSIONS: Maternal exposure to diet and increased Ca:P molar ratio during gestation and lactation led to significant, sex-specific morphologic and TMD changes in 6-week-old mouse skulls.

Chlorhexidine versus organoselenium for inhibition of S. mutans biofilm, an in vitro study.

BACKGROUND: Chemical Plaque control by antimicrobial agent application can defend the teeth against caries. S. mutans is considered the main etiologic factor for caries. This was an in vitro study to compare between the efficacy of chlorhexidine diaceteate varnish, and an organoselenium sealant, to prevent S. mutans biofilm formation on human teeth. METHODS: Fourty five premolars extracted for orthodontic purposes were randomly divided into 3 groups of 15 teeth each. One control group and two test groups, chlorhexidine diaceteate varnish and an organoselenium sealant. The teeth were autoclaved before S. mutans biofilm was induced on to each in their respective groups. The reading T1 was taken for each tooth to assess the number of S. mutans attached in order to compare for differences in surface area among the 3 groups. The respective test materials were applied onto the teeth and biofilm induced onto them in their respective groups. The reading T2 was taken for the 2 test groups. The 3 groups were then subjected to aging for a period equivalent to 5 months before the biofilm was induced to take the reading T3 for the number of S. mutans. We used vortexing of the teeth to disrupt the biofilm at time points T1, T2 and T3. S. mutans count was then done using PCR. RESULTS: There were significantly lower S. mutans counts in the control group as compared to the chlorhexidine diacetate group at T3.There were no other statistically significant differences found. CONCLUSION: Both organoselenium and Chlorhexidine diacetate do not inhibit S. mutans biofilm attachment onto the teeth.

Digital model superimpositions: are different software algorithms equally accurate in quantifying linear tooth movements?

BACKGROUND: To evaluate the accuracy of three different 3D digital model registration software packages for linear tooth movement measurements, with reference to a 3D digital virtual setup (DS). METHODS: Twenty maxillary and mandibular pre-treatment scans of patients undergoing clear aligner therapy were used. Digital Setups were generated from pre-treatment scans using OrthoAnalyzer software. Both the pretreatment digital scans (T1) and Digital Setups (T2) were converted to STL files to be imported to the three studied software packages: Geomagic, OrthoAnalyzer and Compare. Linear changes in tooth positions were calculated for all the registered pairs. RESULTS: The change in tooth position was compared between the calculated tooth movement using each of the registration software packages versus the actual generated tooth movement from the Digital Setups. Continuous data was expressed as mean and standard deviation. Intraclass Correlation Coefficients for agreements between Digital Simulation and each software was used. Intra and Inter-examiner reliabilities were also assessed using Intraclass Correlation Coefficients. Significance of the obtained results was expressed at p ≤ 0.01. Geomagic software showed agreements > 0.90 for maxillary linear tooth movements and between 0.75 and 0.90 for mandibular measurements. OrthoAnalyzer software showed agreements between 0.50 and < 0.75 for maxillary and mandibular measurements. Compare software showed agreements > 0.90 for maxillary and mandibular linear tooth movements, indicating the best consistency. CONCLUSIONS: Compare and Geomagic software packages consistently showed maximum accuracy in measuring the amount of tooth movement in the maxillary arch compared to the reference standard. Compare software showed the highest agreements in the mandibular arch. None of the three studied software packages showed poor agreement with the Digital Setup across all tooth movement measurements. Buccolingual tooth movements showed the highest agreements amongst linear measurements.

How orthodontic research can be enriched and advanced by the novel and promising evolutions in biomedicine.

Recent advances in developmental, molecular and cellular biology as well as biomedical technologies show a promising future for crossing the gap between biomedical basic sciences and clinical orthodontics. Orthodontic research shall utilise the advances and technologies in biomedical fields including genomics, molecular biology, bioinformatics and developmental biology. This review provides an update on the novel and promising evolutions in biomedicine and highlights their current and likely future implementation to orthodontic practice. Biotechnological opportunities in orthodontics and dentofacial orthopaedics are presented with regards to CRISPR technology, multi-omics sequencing, gene therapy, stem cells and regenerative medicine. Future orthodontic advances in terms of translational research are also discussed. Given the breadth of applications and the great number of questions that the presently available novel biomedical tools and techniques raise, their use may provide orthodontic research in the future with a great potential in understanding the aetiology of dentofacial deformities and malocclusions as well as in improving the practice of this clinical specialty.

Altering calcium and phosphorus levels in utero affects adult mouse mandibular morphology.

OBJECTIVES: The purpose of our study was to determine morphological changes and bone mineral density (BMD) differences in the adult mandible of offspring exposed to high calcium, low phosphorus diets in utero until weaning age. MATERIALS AND METHODS: Time-mated FVB wild-type mice were fed normal or experimental diet during gestation and until weaning of offspring. Experimental diet contained 3-fold increase in calcium and 3-fold decrease in phosphorus compared to normal diet. Adult mandibles of offspring exposed to experimental diet were sacrificed and heads scanned using micro-computed tomography. Three-dimensional 3D geometric morphometric analysis GMA was utilized to detect morphological changes to the mandible including the condyle. RESULTS: Experimental females showed the greatest morphological differences including shortened mandibular ramus width and height, shortened mandibular body length and height, a wider but shortened condylar neck and a wider condylar head in the lateral-medial direction. Experimental male mandibles trended towards increased mandibular body height and length, opposite the changes observed in experimental female mandibles, whereas condyles were similar to that observed in experimental females. Bone mineral density (BMD) was lowered in experimental females. CONCLUSION: Increased calcium and decreased phosphorus levels led to a retrognathic mandible associated with lowered BMD in experimental females, whereas experimental showed partly opposite effects. Further studies are required to understand the mechanism underlying diet- and gender-specific differences in mandibular morphology.

Orthodontically induced osteocyte apoptosis under different force magnitudes in rats: an immunohistochemical study.

We investigated the effect of different force magnitudes on osteocyte apoptosis in a model of orthodontic tooth movement. Forty-nine male Sprague Dawley rats (7-9 wk of age) were divided into light- and heavy-force groups (n = 21 each group) and a control group (n = 7). A coil spring delivered pressure (either 10-15 g or 20-25 g) to the left maxillary first molar. The rats were sacrificed 1, 3, or 5 d after placement of the appliance. Sections of the maxillary first molars were immunostained for caspase-3. Upon force application, the number of apoptotic osteocytes significantly increased in the pressure side at 1 d and remained the same at 3 d and 5 d. However, there was no significant difference in the number of apoptotic osteocytes between the two force groups. We conclude that osteocyte apoptosis appears to increase under orthodontic loading, reaching a plateau after 1 d. However, osteocyte apoptosis seems to be independent of the magnitude of orthodontic forces tested.

Global scholarly output on orthodontic temporary anchorage devices (TADs): A silver jublee scientometric analysis.

OBJECTIVES: This study aimed to analyze the global scholarly production of articles related to temporary anchorage devices (TADs) from 1998-2023 in peer-reviewed dental journals indexed in the Web of Science. MATERIALS AND METHODS: A database of TADs-related articles was created via a Web of Sciences structured search. The bibliometric characteristics of the studies, including the number of citations, publication year, journal title, journal impact factor (IF), authorship, contributing institutions and countries, thematic field, and study design, were extracted. Keyword co-occurrence network analyses and the correlation between the number of citations and the article age, journal IF, and journal quartile of each article were performed. RESULTS: The top 50 cited articles were published from 1999-2016, and the total number of citations ranged from 82-602, with 160.36 citations/paper on average. Most of the articles originated from Japan (n = 12), with the most remarkable contributions from Nihon and Okayama Universities, Japan (n = 5, each). The American Journal of Orthodontics and Dentofacial Orthopedics had the most cited articles, with 196.57 citations/paper on average. A significant positive correlation occurred between the number of citations and publication age (rho = 0.392, P = 0.005). CONCLUSION: Our scientometric analysis reported the characteristics of TADs-related articles published over 25 years. Most highly-cited articles were published between 2005 and 2008. The positive correlation between articles' publication date and the number of citations might impact the top 50 within the next 5-10 years.

Quantifying maxillary anterior tooth movement in digital orthodontics: Does the choice of the superimposition software matter?

BACKGROUND: To compare the agreement between predetermined angular and linear tooth movement measurements processed with three digital model registration software packages. METHODS: Twenty maxillary intraoral pretreatment scans of patients undergoing clear aligner therapy were randomly selected. Digital setups were generated using OrthoAnalyzer Clear Aligner Studio software to serve as the reference standard. Both pretreatment scans and setups were converted to STL files and exported to Geomagic, OrthoAnalyzer-Model Set Compare, and Compare model registration software packages. The amount of tooth movement of the maxillary incisors and canines was calculated in six degrees of freedom. RESULTS: Statistical significance of the obtained results was expressed at P < 0.01 to account for multiple comparisons. The maxillary central incisors showed the highest agreement for torque and rotation as measured by all software programs. Lateral incisors showed the least agreement in linear movements as measured by Geomagic and Compare, and for tip as measured by Geomagic and OrthoAnalyzer. Maxillary canines had the highest agreement for all linear movements as measured by Geomagic and Compare, and tip as measured by Geomagic and OrthoAnalyzer. Geomagic showed excellent agreement for all measurements except for torque, whereas Compare showed excellent agreement only for rotation and linear measurements. OrthoAnalyzer showed moderate agreement for all measurements except for rotation, which showed good agreement. CONCLUSIONS: Maxillary central incisor measurements showed higher agreement compared with measurements of the maxillary lateral incisors and canines. Although none of the software showed poor agreement, Geomagic seemed to have the highest accuracy.

World Federation of Orthodontists guidelines for postgraduate orthodontic education.

Advanced dental education programs in orthodontics and dentofacial orthopedics require an extensive and comprehensive evidence-based experience, which must be representative of the current didactic and technical advancements. Over the past 25 years, the World Federation of Orthodontists (WFO) has placed emphasis in the support for the recognized orthodontic specialty training programs in every region of the world. In its early years, the WFO developed general principles for specialty education that culminated in the first comprehensive curriculum recommendations, i.e., the WFO Guidelines for Postgraduate Orthodontic Education, which was published in February 2009. In view of the significant changes in the specialty of orthodontics, the WFO has revised and updated its previous document to reflect the expanded scope and demands of current orthodontic education and practice. The members of the task force participated in a thorough revision of the guidelines and created a new document that takes into consideration the didactic, clinical, and the appropriate physical facilities to provide clinical care, study, and research areas. Although it is recognized that there will be variations in teaching and faculty assets, as well as facilities, access to materials, and equipment, the aim of the WFO Educational Guidelines is to provide the minimum program requirements necessary to provide orthodontic specialty residents the educational experience that prepares them to deliver the best level of orthodontic treatment for their patients. It is recommended that these guidelines be used universally by orthodontic specialty program educators and related educational, scientific, and administrative institutions to evaluate and compare their curriculum to a world standard.

Enamel colour changes after debonding using various bonding systems.

OBJECTIVE: To test the possible association between enamel colour alteration and resin tag depth. DESIGN: In vitro laboratory study. SETTING: Department of Orthodontics, Alexandria University, Egypt. MATERIALS AND METHODS: Fifty freshly extracted human premolar teeth were equally divided randomly into a control and four experimental groups. Teeth in group I received only enamel prophylaxis. Teeth in groups II and III were etched with 35% phosphoric acid for 15 and 60 seconds, respectively. Teeth in group IV were conditioned with Prompt L-pop self-etching primer and in group V with Xeno III self-etching primer, according to the manufacturer's instructions. Orthodontic brackets were bonded to the teeth in all experimental groups using Transbond XT composite. Following bracket debonding, finishing and polishing were performed. Enamel colour was evaluated spectrophotometrically at baseline and then after debonding, with the corresponding colour differences ΔE calculated. Resin tags lengths were measured on sectioned teeth in each experimental group under scanning electron microscope. RESULTS: All experimental groups showed clinically perceivable colour change after debonding and finishing as all values were exceeded the clinical colour detection threshold of ΔE = 3.7 units. Significant differences (P<0.05) in resin tag length were found in all experimental groups. Significant moderate correlation was found between colour change and resin tags length when all teeth were combined and tested, irrespective of group. CONCLUSIONS: Moderate evidence exists that shorter resin tag penetration produces less change in enamel colour following clean-up and polishing. Self-etch primers produce less resin penetration and these systems may produce less iatrogenic colour change in enamel following orthodontic treatment.

TIP, TORQUE & ROTATIONS: How accurately do digital superimposition software packages quantify tooth movement?

BACKGROUND: To investigate the accuracy of three different 3D digital model registration software for tip, torque and rotation measurements, with reference to a 3D digital virtual setup. Twenty maxillary and mandibular pre-treatment scans of patients undergoing clear aligner therapy were used. Digital setups were generated from pre-treatment scans using a tooth movement software. Both the pretreatment digital scans (T1) and digital setups (T2) were converted to STL files to be exported to the 3 studied software that employed: (1) Semiautomatic best fit registration (S-BF), (2) Interactive surface-based registration (I-SB), and (3) Automatic best fit registration (A-BF) respectively. Changes in tip, torque and rotation were calculated for all the registered pairs. RESULTS: The change in tooth position was compared between the calculated tooth movement using each of the registration software packages versus the actual generated tooth movement from the digital setups. Continuous data was expressed as mean and standard deviation. Intra Class Correlation Coefficient for agreement between digital simulation and each software was used. Intra and Inter-examiner reliabilities were also assessed using Intra Class Correlation Coefficient. Significance of the obtained results was expressed at p ≤ 0.01. Semiautomatic best fit registration software showed excellent agreement (> 0.90) for all tooth movements, except for good agreement for torque (0.808). Interactive surface-based registration software showed moderate agreement for all measurements (0.50 and < 0.75), except for good agreement for rotation (0.783). Automatic best fit registration software demonstrated excellent agreement (> 0.90) for rotation, good agreement for tip (0.890) and moderate agreement for torque (0.740). CONCLUSIONS: Overall, semiautomatic best fit registration software consistently showed excellent agreement in superimpositions compared to other software types. Automatic best fit registration software consistently demonstrated better agreement for mandibular superimpositions, compared to others. Accuracy of digital model superimpositions for tooth movements studied in superimposition studies, can be attributed to the algorithm employed for quantification.

Robotic Applications in Orthodontics: Changing the Face of Contemporary Clinical Care.

The last decade (2010-2021) has witnessed the evolution of robotic applications in orthodontics. This review scopes and analyzes published orthodontic literature in eight different domains: (1) robotic dental assistants; (2) robotics in diagnosis and simulation of orthodontic problems; (3) robotics in orthodontic patient education, teaching, and training; (4) wire bending and customized appliance robotics; (5) nanorobots/microrobots for acceleration of tooth movement and for remote monitoring; (6) robotics in maxillofacial surgeries and implant placement; (7) automated aligner production robotics; and (8) TMD rehabilitative robotics. A total of 1,150 records were searched, of which 124 potentially relevant articles were retrieved in full. 87 studies met the selection criteria following screening and were included in the scoping review. The review found that studies pertaining to arch wire bending and customized appliance robots, simulative robots for diagnosis, and surgical robots have been important areas of research in the last decade (32%, 22%, and 16%). Rehabilitative robots and nanorobots are quite promising and have been considerably reported in the orthodontic literature (13%, 9%). On the other hand, assistive robots, automated aligner production robots, and patient robots need more scientific data to be gathered in the future (1%, 1%, and 6%). Technological readiness of different robotic applications in orthodontics was further assessed. The presented eight domains of robotic technologies were assigned to an estimated technological readiness level according to the information given in the publications. Wire bending robots, TMD robots, nanorobots, and aligner production robots have reached the highest levels of technological readiness: 9; diagnostic robots and patient robots reached level 7, whereas surgical robots and assistive robots reached lower levels of readiness: 4 and 3, respectively.

Tooth transposition: a review and clinical considerations for treatment.

This article reviews the literature on tooth transposition. Several cases with various types and combinations of tooth transposition are presented and treatment management and options are discussed. Indications, advantages, and disadvantages of correcting versus maintaining tooth order are shown.

Treatment of various degrees of white spot lesions using resin infiltration-in vitro study.

BACKGROUND: This study was conducted to evaluate the efficiency of resin infiltration to improve the color of white spot lesions (WSLs) and to estimate the effect of different numbers of etching and resin infiltrant applications on the color change of WSLs with various depths. Ninety-six sound extracted premolars were subjected to acid attack inducing different depths of WSLs. Using a DIAGNOdent, teeth were divided into four main groups according to the depth of the WSLs: shallow enamel, deep enamel, shallow dentine, and deep dentine without cavitation. Then each of the main groups was subdivided into four groups: six teeth each with different protocols of resin infiltration as follows: 1 etching + 1 infiltrant application (EA), 1 etching + 2 infiltrant applications (EAA), 2 etchings + 1 infiltrant application (EEA), 2 etchings + 2 infiltrant applications (EEAA). Spectrophotometric analysis was measured at baseline (T0), after inducing the WSLs (T1), and following resin infiltration application (T2) for each group. RESULTS: In shallow enamel, EA produced the least mean color difference (1.62 ± 0.85), with high significant difference (P < 0.001), when compared with the clinically detectable threshold (ΔE = 3.7). While in deep enamel, EAA showed the least mean color change (1.95 ± 0.4), with P < 0.001 when compared with the critical value. Also, in shallow dentine, the least mean change was noticed with EAA (3.0 ± 0.45), with P < 0.001 when compared with the clinical color detection threshold. Furthermore, in deep dentine, EAA had the least mean difference (3.76 ± 0.6) but with no significant difference, when compared with the clinically detectable threshold. CONCLUSIONS: As the WSL got deeper, the color of the lesion became more clinically visible. In shallow enamel, the best treatment option was one etching with one resin infiltrant application. For deep enamel and shallow dentine, one etching with two applications of infiltrant gave the best lesion masking. In deep dentine, it is advisable to perform one etching with two infiltration steps, taking in consideration that all deep dentine lesions without cavitation were partially masked, remained clinically detectable, and might require more invasive restorative procedures.

Sclerostin Modulation Holds Promise for Dental Indications.

Sclerostin modulation is a novel therapeutic bone regulation strategy. The anti-sclerostin drugs, proposed in medicine for skeletal bone loss may be developed for jaw bone indications in dentistry. Alveolar bone responsible for housing dentition share common bone remodeling mechanisms with skeletal bone. Manipulating alveolar bone turnover can be used as a strategy to treat diseases such as periodontitis, where large bone defects from disease are a surgical treatment challenge and to control tooth position in orthodontic treatment, where moving teeth through bone in the treatment goal. Developing such therapeutics for dentistry is a future line for research and therapy. Furthermore, it underscores the interprofessional relationship that is the future of healthcare.

Anchorage loss during canine retraction using intermittent versus continuous force distractions; a split mouth randomized clinical trial.

OBJECTIVES: The aim of this study was to evaluate the anchorage loss, amount and time of canine retraction, and canine tipping concomitant with periodontal ligament distraction (PLD) using intermittent and continuous forces. MATERIALS AND METHODS: This was a split mouth randomized clinical trial involving 30 patients in need of first premolar extraction. For each patient, one side was randomly allocated to receive a screw-based dental distractor, and the other side a continuous force coil spring distractor. Molar and canine movements were recorded on study casts using the rugae as reference. Changes in the long axis of the canines were evaluated from pre- and post distraction panoramic radiographs. RESULTS: On the screw side, molars moved mesially 2.5±0.9 mm. The canine tipped distally a mean of 10.5°±3.1°. The average time needed for canine retraction was 5.3±1.3 weeks. In the coil side, the molar mesial movement was not statistically different from the screw group (2.8±1.5 mm). The canine moved bodily with a mean distal tip of 0.27°±1.75° in a period of 27.8±6.6 weeks. CONCLUSIONS: Anchorage loss occurs with dental distraction using either intermittent or continuous force. No significant difference in anchorage loss was found with either type of force. The surgical intervention did not shorten the time needed for canine retraction using the continuous force. Continuous force leads to slow bodily retraction of the canine unlike the intermittent force which leads to rapid tipping of the canine.