Anchorage in Orthodontics- A Review

Anchorage in alveolar orthopedics- A Revieworthodontics is the branch of dentistry concerned with facial growth, the development of the dentition and occlusion, and the diagnosis, interception and handling of occlusal anomalies. The goal of orthodontic dis drift is to improve the persons life by enhancing alveolar and jaw function and dentofacial esthetics. This is achieved by obtaining optimal proximal and occlusal come across of dentition (occlusion) within the frame live on of normal function and physiologic adaptation, acceptable dentofacial aesthetics and self-image and reasonable stableness (Graber and Vanarsdal, 1994). Conventional orthodontic sellment is achieved using mend and obliterable doojiggers to achieve a excogitatened end percentage point of discussion.orthodontic lynchpinage ground is an main(prenominal) concept in orthodontic interposition, and crowd out be reinforced by some(prenominal) types of thingmajigs. Orthodontic headdress has tradition in ally been considered to be the gold standard apparatus for reinforcing anchorage ground. However, an increasing aw arness of the drawbacks of headdress, mainly scummy tolerant compliance and serious nitty-gritty injuries, has led to the development of appliances in which the evidence base supporting their economic consumption is incomplete. In extension, it has been suggested that handlingable appliances which atomic look 18 traditionally utilise for growth modification, can be utilize for anchorage training.In this incision, the concept of anchorage in orthodontic word is reviewed. The exposition of anchorage is presented including its relationship to blank requirements, rootages and certain appliances, including the probable of using structural appliances for anchorage.As the effectiveness of some of these appliances has been evaluated by randomized trial mannerology (RCT), an account of the bias that can arise in RCTs is inclined and the effectivenes s effect this bias may take over on the trial results.Finally, the important aspect of broadsidement of variables in orthodontic rese implike is reviewed focusing on the reliability and validity of new measurement methods using computer softw atomic number 18 and digital posers.1.2.1 Definition and importanceAnchorage in orthodontics can be defined as the resistance to unwanted tooth effect 1. When an orthodontist/dentist plans treatment they evaluate the anchorage requirement by estimating the amount of dummy that is needed to correct the malocclusion. Anchorage or space may be obtained by extracting teeth, mournful teeth into certain position and/or the make use of of orthodontic appliances. Achieving anchorage can be obtained by one of the hobby methods1.2.2 Maximising the potential of available teethIn this method a force is apply amid two points (tooth or groups of teeth) and tooth try is controlled by making one point much(prenominal) resistant to movement than the other. This is through with(p) by careful planning of the site of force application. Examples admit alive(p) movement of one tooth versus several(prenominal) anchor teeth, for example correcting the centreline by moving one tooth at a time.Teeth of greater resistance to movement are utilized as anchorage for the translation of teeth that excite less resistance to movement. A common example of this is closing space by pitting the posterior teeth (greater resistance) against the antecedent teeth (less resistance). channelise magnitude the number of teeth in the anchor unit, examples areAdding the guerrilla zep to the rooted(p) appliance.Adding the anterior teeth to reinforce posterior anchorage by bending loops mesial to the kickoff torpedos.Adding teeth from the opposing arch to the anchor unit by utilizing inter-arch elastics.Making movement of anchor teeth much difficult, for example putting a tip- back bend in first molars.Using ankylosed teeth as anchors.1.2.3 Prov iding an additional form of orthodontic applianceThe anchorage gained from the anterior methods is limited. As a result, it is needed to reinforce the anchorage with an additional appliance. The nearly commonly used orthodontic anchorage devices areExtra oral anchorage (EOA) with headgearIntraoral anchorage with palatal and linguistic arches.1.2.4 headgearHeadgear is an orthodontic appliance that is used to apply forces to the teeth utilising organises outside the oral cavity. Headgear is usually applied to the first maxilla molar via a tube attached to the molar band. The force necessary to fork up extra oral anchorage is 200 to 250 gm applied for 10-12 hours per day 2.Headgear was first used for anchorage by Kingsley in 1866 to retract upper incisors in an upper premolar pedigree reference 3. This was followed by Angle in 1888 and Case in 1907 3. In 1953, Kloehn create the contemporary design of headgear that orthodontists use today 3.Since then, headgear has been use d naturalizedly when maximum anchorage is required. As a result, it may be considered the gold standard for anchorage in orthodontic anchorage.1.2.5 Disadvantages of headgearThe use of headgear has the following disadvantages or risksCompliance From the early days of headgear use, it was out-of-doors that substantial compliance was required and failure to stand headgear, for the decreed amount of time, was recognised 3. Headgear compliance is metric as the divergence amidst real(a) hours of wear and invoice hours of wear and has been evaluated in several studies. Results of these studies have been discouraging as the actual hours of wearing headgear appear to be much humble than that required 4-6. For example, Brandao et al in 2006 suggested that perseverings who had been asked to wear their headgear for 14 hours a day, reported wearing their headgear an bonny of 13.6 hours a day while the actual hours of wear were only 5.6 hours 4. scratch 6 and Cureton 5 also found t hat the reported hours of wear were much less than the actual hours of wearing headgear . dim tissue injuries Apart from minor injuries to the border intraoral and extra oral soft tissues, serious ocular injuries have been reported both in Europe and the get together States. In some of these instances sightlessness has resulted as a last-place result of the injury. Ten eye injuries have been reported in the belles-lettres 2 in the UK, 3 in France, 2 in Italy, 1 in Germany and 2 in the United States 7, 8. These injuries resulted from one of several factors including dislodgement during sleep, improper removal of headgear or improperly playing with the headgear.Nickel Allergy A small caboodle of the population pull up stakes exhibit sensitivity to the Nickel alloy in facebows 9-11. Nickel allergies in response to orthodontic appliances are not considered a major health risk.Exacerbation of pre-existing eczema thither has been a shell reported in the literature in which an incr ease in the severity of a pre-existing atopic eczema was observed afterwards headgear wear 12.It is transparent from the problems mentioned that the most material drawbacks of headgear use are non-compliance and serious eye injuries. Several measures have been taken to overcome these two problems with varying amounts of success.1.2.6 improve headgear complianceSuggestions have been made in the literature to bring forward patients to increase the actual number of hours in which headgear is worn these include the followingThe use of a headgear calendar 13,The use of a headgear timer or electronic monitoring device and inform the patient of its presence 14,The use of conscious hypnosis for patient motivation during headgear wear 15,Treatment by a defined behavioural model which depends on a schedule for wearing headgear, in addition to enatic observations and rewards based on patient compliance. This behavioural model is flexible and will evolve according to the patients respon se and needs 16,Promoting headgear wear by considering gender differences, making patients more aware of their malocclusions and the effect of treatment 17.1.2.7 Headgear rubber eraser mechanismsSeveral features have been added to headgear in an attack to restrain elastic recoil injuries or unintentional detachment of the headgear. These include operate on mechanisms which prevent release of the facebows from the molar tubes 18,Snap-release headgears which prevent elastic recoil of the facebows when an unwarranted force is used 7,Plastic safety straps which attempt to limit the movement of the facebows 7,Intraoral elastics to attach the inner bow to the molar tube 7,Blunting and smoothening the ends of the facebows to reduce the potential for injury 7.It has been recommended that at least(prenominal) two of these mechanisms are used at the same time in addition to clear verbal and written instructions to the patients and parents 19.In summary, headgear is considered the gold s tandard appliance for providing anchorage. However, in order for it to work effectively, it requires a material amount of patient cooperation and compliance. There have been many attempts to improve headgear compliance, which is a reflection of the failure to overcome this problem. Finally, there are several safety issues relate to headgear, which may discourage patients and orthodontists from its use.The archetype solution would be to use an anchorage device that provides at least the same anchorage potential as headgear, but requires little or no compliance. This has led to the development of running(a) anchorage devices.1.2.3 Surgical anchorageIn this thesis I will use the term surgical anchorage to denote all types of anchorage devices which are surgically move in the maxilla or trim back jaw. The use of implants for orthodontic anchorage is a rapidly developing field and appears to be very promising. It has evolved from using conventional restorative implants in the line of the arch to more specialized palatal implants and mini-plates, to mini-screw implants.Types of surgical anchorage include mini-screw implants, mini-plates and midpalatal implants. The mini-screw implant is a modification of screws used for fixation of maxillofacial fractures. Although they have varying lengths and diameters, they are generally smaller than maxillofacial fixation screws, hence the term mini. It is also important to realise mini-screw implants from midpalatal implants which can be used for orthodontic anchorage, as the latter are endosseous implants and a modification of prosthetic implants. Mini-plates are small surgical plates that moldiness be surgically screwed to bone under the soft tissue.Mini-screw implants may provide anchorage reinforcement because of the combination of mechanical retention immediately after insertion (primary stability) and a degree of osseointegration. Mini-plates provide a stable structure fixed to bone for application of forces and midpalatal implants offer stability by osseointegration. disdain the widespread adoption of this type of technology, there is a dearth of noble forest clinical research into their effectiveness. The literature concerning their use is referenced in section III as part of the systematic review.1.2.4 path II operative(a) appliancesFunctional appliances are orthodontic appliances that utilize the facial and masticatory muscle system to dumbfound orthodontic forces. They are commonly used in the treatment of Class II malocclusions. They can either be removable, for example the Clarks agree clog appliance, or fixed, for example, the Herbst appliance. In the UK, the most popular functional appliance for treating Class II malocclusions is the Twin Block 20.Functional appliances were developed to treat malocclusions by growth modification, by encouraging polarial growth of the mandibula and maxilla. In Class II malocclusions the objective is to encourage growth of the mandible and /or restrain growth of the maxilla. While this theoretical effect of functional appliances is often quoted, the evidence behind these concepts is lacking. Recently, there have been a number of randomized clinical trials evaluating the impecunious effect of functional appliances. These are summarised in a Cochrane systematic review published in 2013 which assessed and analysed outcomes of 17 studies 21.These studies produce interesting results. When early two-phase treatment with a functional appliance was compared to jejune one phase treatment (patients who did not receive a functional appliance), there was no difference in the final ANB (MD -0.02, 95% CI -0.47 to 0.43. P = 0.92). Similarly, when a comparison was made for early treatment among headgear and functional appliances, there was no difference in the final ANB (MD -0.17, 95% CI -0.67 to 0.34, P = 0.52). When functional appliance treatment was performed in adolescents and compared to un interact controls, there was a stat istically significant difference in ANB (MD -2.37, 95% CI -3.01 to -1.74, P It was concluded from the results of these trials that the amount of skeletal change (growth modification), from the use of functional appliances is small and is unlikely to be clinically significant. Nevertheless, it is clear that these appliances are very effective in the correction of Class II malocclusion primarily through dentoalveolar movements.The following effects of Twin Block treatment are clinically usefulEnhancing facial appearance 22, 23Distalising upper molars and molar correction 24, 25Reducing the overjet 24-30Proclination of lower incisors 24-26, 28, 30, 31Retroclination of upper incisors 24-26, 28, 30A case report using Twin Blocks to treat a Class II piece II case suggested that a Twin Block can be used instead of headgear derived anchorage 32. When we consider the preparation of orthodontic anchorage it is common clinical experience that molar correction and the lessening of the overjet are major factors in reducing the anchorage requirements of a case. As a result, some clinicians use functional appliances in anchorage preparation with the aim of avoiding dental declensions or other forms of anchorage. A common method of achieving this is by utilizing a 2-phase treatment protocol during adolescence 33. The first phase of treatment is achieved by using only a functional appliance. This phase usually continues until the overjet and/or molar relationship is corrected. The clinician may then choose to cover the correction obtained by the functional appliance by keeping the functional appliance in place or by using a simple removable appliance 34. This is immediately followed by a second phase of active fixed orthodontic treatment.1.2.5 ExtractionAs mentioned in the previous section, the anchorage requirements of a case are related to the space available in the upper and lower arches. It is common orthodontic fare to change anchorage requirement by the parentage o f teeth 2.The literature examining factors influencing the extraction decisiveness can be divided into three different methodologies according to the method of line of business. These are (i) the studies that directly ask clinicians their verbalise reasons for extraction, (ii) studies that measured the set of the presence or absence of a cephalometric radiograph on the stopping point to extract, and (iii) studies that define some patient characteristic, such as cephalometric variables or orthodontic indices, and attempt to identify a correlation among these characteristics and whether or not extractions had been undertaken. I will discuss these studies in the following section1.2.5.1 Clinicians stated reasons influencing the extraction decisionOnly one write up, Baumrind et al, directly asked orthodontists the factors that were related to their decision to extract teeth as part of a course of treatment 35. In this study full orthodontic records of 72 patients were abandoned t o 5 clinical instructors in a University setting in the USA. They were minded(p) a treatment planning form to complete for each patient include in the form were questions about the extraction decision and the reasons for extraction. The clinicians stated that the most important reasons for extraction were move (49%), followed by incisor protrusion in 14% and profile advance in 8%. Other, less frequent, reasons were caution over Class II severity and concern for post- treatment stability (5%). No other single reason was stated as the most important reason in more than 2% of the forms. When considering all replies, crowding was cited in 72% of forms, incisor protrusion in 35%, profile improvement in 27% and Class II severity in 15%. No other single reason was stated in more than 9% of forms.This was a simple mark-sectional study, in which the patient records and the participants were a convenience precedent. It does, however, provide some relevant information on the reasons for extraction.1.2.5.2 Cephalometric radiographs influencing the extraction decisionThere have been several studies that have evaluated the effect of radiographs on the extraction decision. For example, Devereux et al 36 carried out a study in which a group of orthodontists were sent the orthodontic records of 6 patients on a CD, not containing lateral cephalometric radiographs or tracings, and were asked if they would extract teeth (T1). At this point, the orthodontists did not spang that they were to be asked to examine the cases again after a washout period. by and by a period of 8 weeks (T2), the orthodontists were sent the records of the same 6 patients, but the lateral cephalometric radiographs and tracings were include in the records. They were asked again if they would extract teeth. The decisions made by this group (group A) were compared to another group of orthodontists (group B) who had full patient records, including lateral cephalometric radiographs and tracings, at both T1 and T2. It was found that the orthodontists in group A were 1.7 (95% CI, 1.0-2.8) times more likely to change their extraction decision than those in group B (odds ratio).In a similar investigation, Nijkamp et al investigated the influence of lateral cephalometric radiographs on the treatment planning decision 37. This was a crossover design in which symptomatic records of 48 patients were given to 10 orthodontic postgraduates and 4 orthodontists. They were asked to speculate a treatment plan based around a dichotomous decision regarding three treatment options (i) extraction, (ii) the use of a functional appliance and (iii) the use of rapid maxillary expansion. The diagnostic records at T1 included dental casts, but did not include a lateral cephalometric radiograph. T2 was 1 month later, and included both dental casts and lateral cephalometric radiographs and values. This design was repeated so that at T3, which was one month after T2, only dental casts were included and at T4, which was one month after T3, dental casts and lateral cephalometric radiographs were included in the diagnostic records. Agreement between the treatment planning decision with and without the lateral cephalometric radiograph was assessed. In order for the treatment plans to agree, decisions about all three treatment options had to be the same. There was no statistically significant difference in the treatment plans between the use of only dental casts or with additional cephalometric information (P = 0.74).Another study by Han et al evaluated the effect of the incremental addition of diagnostic records on the extraction decision 38. Five orthodontists provided a treatment plan for 57 patients. Orthodontic records were given to each of the five orthodontists in the following order posing 1 study models onlySession 2 study models and facial photographsSession 3 study models, facial photographs, and panoramic radiographsSession 4 study models, facial photographs, panoramic and lat eral cephalometric radiographs.Session 5 all the previous records in addition to a lateral cephalometric tracing.The time interval between each sitting was 1 month, and the records were re-numbered between sessions. In each session, the orthodontists were asked to take aim a treatment pathway from a decision tree. The end point of each of the treatment pathway was a decision on whether or not to extract. The treatment planning decisions for each of the orthodontists in session 5 was considered the gold standard for that clinician. As a result, the proportion of agreement between the treatment plan in each of the four sessions and the treatment plan in session 5 was obtained. The proportions of agreement between sessions 1, 2, 3, 4 and session 5 were 55%, 55%, 65% and 60% respectively. Therefore, they concluded that study models alone are adequate for treatment planning, and that the addition of other types of diagnostic records made only a small difference.These three studies were good quality cross-sectional studies. The randomisation and method of washout were clear strengths of the studies. In addition experiment distribution size calculations were undertaken in two of these studies Devereux et al and Nijkamp et al.1.2.5.3 Patient characteristics influencing the extraction decisionThe final type of studies evaluating the extraction decision are studies which attempt to identify a correlation between patient characteristics and whether or not extractions had been undertaken. Two studies, Xie et al and Takada et al, used a mathematical model to take a decision-making Expert System (ES), which could formulate treatment decisions. 39, 40. ES is a branch of artificial intelligence in which the computer programme simulates the decision-making and working processes of experts and solves clinical problems. They developed a model in which twenty-five patient characteristics were tested on 180 do by patients 39. The rate of coincidence between the recommendation s given by the optimized model and the actual treatments performed was found to be light speed%. The characteristics that influenced the extraction decision were the anterior teeth uncovered by unentitled lips and IMPA (L1-MP). Another similar study was carried out by Takada et al when they selected 25 patient characteristics and 188 treated patients in their model 40. The rate of coincidence between the recommendations given by the model and the actual treatment performed was 90.4%. The characteristics mostly influencing the extraction decision were incisor overjet and upper and lower arch length discrepancies.Heckmann et al investigated the influence of the angulations between the first and second lower molars on panoramic x-rays, on the extraction decision 41. They used a sample of 30 patients treated by a premolar extraction approach, and a further matched sample of patients treated with a non-extraction approach. Pre- and post-treatment panoramic x-rays were scanned and compu ter software used to measure the angulations between lower first and second molars. Comparison between the blotto angulation of the molars before treatment in the extraction and non-extraction group was not significant.Li et al compared mean cephalometric parameters and model analysis of Class II incision 1 patients who were treated with either an extraction or non-extraction approach 42. The sample consisted of 81 patients 42 who had 4 premolar extractions and 39 who had non- extraction treatment. The extraction group had statistically significant greater values for the following parameters arch length discrepancy, curve of spee, upper incisor tip, Frankfort-mandibular plane angle and lower anterior facial height.Bishara et al compared patient characteristics of Class II division 1 patients who were treated with either an extraction or non-extraction approach 43. The sample consisted of 91 patients 44 had first premolar extractions and 47 who had non-extraction treatment. A stati stically significant difference was found between the extraction and non-extraction groups with regards to the following parameters upper and lower arch length discrepancy, upper and lower lip protrusion in relation to the aesthetic plane in male patients, and the protrusion of the lower lip in female subjects.These studies were ex post facto in nature. There were variations among the studies in the application of inclusion criteria in an attempt to control the characteristics of patients included in the study. Nevertheless, selection bias was inevitably present in these studies. Bias collect to periodical changes may also be present overdue to the retrospective nature of the studies.In summary, studies evaluating the factors influencing the extraction decision are few in number. They have been carried out by gathering the opinion of clinicians in cross sectional studies or by conducting retrospective investigations on a sample of cases in which teeth were extracted as part of or thodontic treatment. The main deficiencies of the studies were due to inadequate selection and number of the study sample and bias arising from their retrospective nature.References1.Roberts-Harry, D. and J. Sandy, dental orthopedics. Part 9 Anchorage control anddistal movement. British alveolar ledger, 2004. 196(5) p. 255-263.2. Mitchell, L., An Introduction to orthodonture. Second Edition ed. 2002, Oxford,UK Oxford University Press.3. Charles T, P., Jr., Cervical headgear usage and thebioprogressive orthodonticphilosophy. Seminars in Orthodontics, 1998. 4(4) p. 219-230.4. Brandao, M., H.S. Pinho, and D. Urias, Clinical and quantitative sagacity ofheadgear compliance a pilot study. American journal of Orthodontics Dentofacial Orthopedics, 2006. 129(2) p. 239-44.5. Cureton, S.L., F.J. Regennitter, and J.M. Yancey, Clinical versus quantitativeassessment of headgear compliance. American Journal of Orthodontics Dentofacial Orthopedics, 1993. 104(3) p. 277-84.6. Cole, W.A., Accura cy of patient inform as an indication of headgearcompliance. American Journal of Orthodontics Dentofacial Orthopedics, 2002.121(4) p. 419-23.7. Samuels, R.H.A. and N. Brezniak, Orthodontic facebows safety issues andcurrent management. Journal of Orthodontics, 2002. 29(2) p. 101-7.8. Samuels, R.H., A review of orthodontic face-bow injuries and safety equipment.American Journal of Orthodontics and Dentofacial Orthopedics, 1996. 110(3) p.269-272.9. Burden, D.J. and D.J. Eedy, Orthodontic headgear related to sensitised contactdermatitis a case report. British Dental Journal, 1991. 170(12) p. 447-8.10. Lowey, M.N., Allergic contact dermatitis associated with the use of an Interlandiheadgear in a patient with a account of atopy. British Dental Journal, 1993. 175(2)p. 67-72.11. Kerosuo, H.M. and J.E. Dahl, Adverse patient reactions during orthodontictreatment with fixed appliances. American Journal of Orthodontics DentofacialOrthopedics, 2007. 132(6) p. 789-95.12. McComb, J.L. and C.M. King, Atopic eczema and orthodontic headgear. DentalUpdate, 1992. 19(9) p. 396-7.13. Cureton, S.L., F.J. Regennitter, and J.M. Yancey, The economic consumption of the headgearcalendar in headgear compliance. American Journal of Orthodontics Dentofacial Orthopedics, 1993. 104(4) p. 387-94.14. Doruk, C., U. Agar, and H. Babacan, The role of the headgear timer in extraoralco-operation. European Journal of Orthodontics, 2004. 26(3) p. 289-91.15. Trakyali, G., et al., Conscious hypnosis as a method for patient motivation incervical headgear weara pilot study. European Journal of Orthodontics, 2008.30(2) p. 147-52.16. Gross, A.M., G. Samson, and M. Dierkes, Patient cooperation in treatment withremovable appliances A model of patient noncompliance with treatment implications. American Journal of Orthodontics, 1985. 87(5) p. 392-397.17. Clemmer, E.J. and E.W. Hayes, Patient cooperation in wearing orthodonticheadgear. American Journal of Orthodontics, 1979. 75(5) p. 517-24.18. Samuels, R., et al., A clinical evaluation of a locking orthodontic facebow.American Journal of Orthodontics and Dentofacial Orthopedics, 2000. 117(3) p.344-350.19. ADVICE ON THE USE OF HEADGEAR, D.A.S.C. The British OrthodonticSociety (BOS), Editor.20. Chadwick, S.M., P. Banks, and J.L. Wright, The use of myofunctional appliancesin the UK a survey of British orthodontists. Dental Update, 1998. 25(7) p. 302-8.21. Thiruvenkatachari, B., et al., Orthodontic treatment for prominent upper frontteeth (Class II malocclusion) in children. Cochrane Database of taxonomicReviews 2013, Issue 11. Art. No. CD003452. DOI10.1002/14651858.CD003452.pub3., 2013.22. OBrien, K., et al., Early treatment for Class II malocclusion and perceivedimprovements in facial profile. American Journal of Orthodontics DentofacialOrthopedics, 2009. 135(5) p. 580-5.23. Singh, G.D. and W.J. Clark, Soft tissue changes in patients with Class II Division 1malocclusions treated using Twin Block appliances finite-element scalinganalys is. European Journal of Orthodontics, 2003. 25(3) p. 225-30.24. OBrien, K., et al., authorisation of early orthodontic treatment with the Twin-blockappliance a multicenter, randomized, controlled trial. Part 1 Dental and skeletaleffects. American Journal of Orthodontics Dentofacial Orthopedics, 2003.124(3) p. 234-43 quiz 339.25. Keeling, S.D., et al., Anteroposterior skeletal and dental changes after early ClassII treatment with bionators and headgear. American Journal of Orthodontics Dentofacial Orthopedics, 1998. 113(1) p. 40-50.26. Illing, H.M., D.O. Morris, and R.T. Lee, A prospective evaluation of Bass,Bionator and Twin Block appliances. Part IThe hard tissues. European Journal ofOrthodontics, 1998. 20(5) p. 501-16.27. Thiruvenkatachari, B., et al., Comparison of Twin-block and Dynamax appliancesfor the treatment of Class II malocclusion in adolescents a randomized controlledtrial. American Journal of Orthodontics Dentofacial Orthopedics, 2010. 138(2)p. 144.e1-9 discussion 144-5.28. OBrien, K., et al., Effectiveness of treatment for Class II malocclusion with theHerbst or twin-block appliances a randomized, controlled trial. American Journalof Orthodontics Dentofacial Orthopedics, 2003. 124(2) p. 128-37.29. OBrien, K., et al., Early treatment for Class II Division 1 malocclusion with theTwin-block appliance a multi-center, randomized, controlled trial. AmericanJournal of Orthodontics Dentofacial Orthopedics, 2009. 135(5) p. 573-9.30. Tulloch, J.F.C., W.R. Proffit, and C. Phillips, Outcomes in a 2-phase randomizedclinical