Objective: The objective was to compare the shear bond strength (SBS) and the adhesive remnant index (ARI) amongst six orthodontic bracket groups. Materials and Methods: Three-dimensional printed polycrystalline alumina brackets (3DBs), ceramic brackets (CBs), and metal brackets (MBs), divided into six groups, were bonded to bovine incisors using different bonding procedures. The SBSs were obtained using a universal testing machine, and the ARIs were assessed with a stereomicroscope. The statistical analyses included one-way analysis of variance (ANOVA) for SBS differences and Fisher’s exact test to show ARI differences amongst the groups (p < 0.05). Results: No significant differences (p > 0.05) were measured amongst the SBSs of the 3DB groups (12.3 MPa, 12.6 MPa, 12.3 MPa, 11.0 MPa, respectively). The latter four groups generally had significantly lower SBSs (p < 0.001) than the conventional bracket groups, CB and MB (16.9 MPa and 19.3 MPa, respectively). Also, there was no significant difference in SBSs for the CB and MB groups (p > 0.05). A high ARI for CBs and MBs (2) indicated that more than 50% of the adhesive remained on the enamel surface. The four 3DB groups had no residual adhesive or less than 50% adhesive on the enamel surface after debonding (ARI scores 0 and 1). A significant difference in ARI levels existed across the types of brackets (p < 0.05). Conclusion: Three-dimensional printed polycrystalline alumina brackets exhibited adequate SBS values for successful bonding. However, the values were lower compared to those for conventional ceramic and metal brackets. The majority of the adhesive remnant for the 3D-printed brackets was mainly located on the bracket base.

Objective: The purpose of this study was to evaluate the morphologic characteristics of MLD malocclusions using 3D imaging. Materials and methods: MLD characteristics were examined using CBCT data in 40 subjects. A 3D Cephalometric analysis was developed to describe the spatial position of the mandible and temporal bones. Results: Vertical dental heights were shorter and the posterior occlusal plane (POP) presented a steeper sagittal inclination on the shifted side (the side of the laterally displaced bony chin) than on the contralateral side. (p < 0.01). The MLD was related to a superiorly inclined POP Cant in the same direction (r = 0.82; p < 0.01). The shifted side condyle was dislocated medially and was smaller. Temporal bone sagittal inclination showed a more forward and medial inclination on the contralateral side (p < 0.01). Conclusions: A unilateral decrease in the vertical height of the dentition and the subsequent steeper occlusal plane inclinations correlated with (1) mandibular rotational displacement and condylar lateral displacement, (2) mandibular and condylar morphologic changes (3) changes in temporal bone position.

Orthodontic treatment with clear aligners is a quickly growing sector of orthodontic treatment. Both the increase in awareness of esthetics and the increase in orthodontic treatment demand from adults has fueled the demand for a more esthetic orthodontic treatment technique. The public demand for fast and esthetic treatment has been addressed by other dental sectors with approaches such as "instant orthodontics" in which crowns or veneers are used to mask malalignment or with products that claim to use "new techniques" to simply align anterior teeth without addressing other aspects of the occlusion that may need treatment to maintain a healthy dentition. Obviously, these types of approaches raise ethical concerns and the need to educate the public as to the shortfalls of these types of approaches. Fixed appliances have become smaller and more esthetically acceptable with the development of ceramic brackets, but they are still more noticeable than clear aligners. Dozens of companies worldwide now offer some type of clear aligner orthodontic product. While research has been done in the area of clear aligners, much of the early research was focused on trying to discredit the use of aligners as an option for orthodontic treatment except for minor crowding or spacing cases. Even so, there was some research that was done to further improve and progress the clear aligner technique. This is still a rapidly developing area and as a result, much of the literature consists of case reports. (C) 2017 Published by Elsevier Inc.

Retention protocols remain controversial despite the fact that long-term stability is rarely observed in orthodontics. In this review article, we examine current evidence and discuss emerging trends to managing retention which may ultimately improve patient care. Our goal is to provide information that may help overcome the gap between scientific evidence and clinical practice. (C) 2017 Elsevier Inc. All rights reserved.

Introduction: The purpose of this study was to examine the relationship of the 3-dimensional (3D) posterior occlusal plane (POP) and the mandibular 3D spatial position. The relationship of the POP to mandibular morphology was also investigated. Methods: Retrospective data from a convenience sample of pretreatment diagnostic cone-beam computed tomography scans were rendered using InVivo software (Anatomage, San Jose, Calif). The sample consisted of 111 subjects (51 male, 60 female) and included growing and nongrowing subjects of different races and ethnicities. The 3D maxillary POP was defined by selecting the cusp tips of the second premolars and the second molars on the rendered images of the subjects. The angles made by this plane, in reference to the Frankfort horizontal plane, were measured against variables that described the mandibular position in the coronal, sagittal, and axial views. The POP was also compared with bilateral variables that described mandibular morphology. Results: There were significant differences of the POP among the different skeletal malocclusions (P < 0.0001). The POP showed significant correlations with mandibular position in the sagittal (P < 0.0001), coronal (P < 0.05), and axial (P < 0.05) planes. The POP also showed a significant correlation with mandibular morphology (P < 0.0001). Conclusions: These findings suggest that there is a distinct and significant relationship between the 3D POP and the mandibular spatial position and its morphology.

OBJECTIVES:To test the following two hypotheses: 1) different types of retainers result in distinct levels of biomarkers in gingival crevicular fluid (GCF) and 2) the retainer bonded to all mandibular anterior teeth induces more detrimental outcomes to the periodontium.SETTING AND SAMPLE POPULATION:The Department of Orthodontics at the University of Florida. The population consisted of individuals in the retention phase of orthodontic treatment.MATERIAL AND METHODS:This was a cross-sectional study that enrolled 36 individuals. Subjects in group 1 had retainers bonded to the mandibular canines only. Group 2 consisted of individuals having retainers bonded to all mandibular anterior teeth. Group 3 included patients using mandibular removable retainers. After clinical examination, GCF was collected from the mandibular incisor and biomarker levels were compared between the groups.RESULTS:Plaque accumulation and gingivitis differed significantly among groups, with the highest median values in group 2 subjects. Pairwise comparison of the groups with respect to gingivitis showed significant differences between groups 1 and 2. Significant differences among groups were detected for RANKL, OPG, OPN, M-CSF, MMP-3, and MMP-9. The ratio RANKL/OPG was significantly higher in group 2 subjects, with pairwise comparisons indicating that groups 1 and 2 differed from group 3.CONCLUSION:An association was found between orthodontic retention groups and GCF biomarker levels, which should be further explored in longitudinal studies. The presence of retainers bonded to all anterior teeth seems to increase plaque accumulation and gingivitis.

White spot lesions and gingivitis represent common, yet challenging, dilemmas for orthodontists. Fluoride has shown some benefit as a protective measure against demineralization; however, this is usually insufficient for orthodontic patients with less than ideal oral hygiene. Dentifrices containing calcium sodium phosphosilicate bioactive glass (NovaMin) have been proposed to aid in prevention of white spot lesions and gingival inflammation. Thus, the purpose of this study was to determine if the use of NovaMin reduces the formation of white spot lesions and improves gingival health in orthodontic patients.

Themostappropriate timing forthetreatment of Class IImalocclusions iscontroversial. Someclinicians advo- cate starting afirst phase inthemixeddentition, followed bya phase 2inthepermanent dentition. Others seenoclear advan- tagetothat approach andrecommend that theentire treat- mentbedoneinthelate mixedorearly permanent dentition. Thisstudy examines howorthodontists, blinded totreatment approach, perceive theimpact ofphase 1treatment onphase 2 needs. Thesample consisted of242Class IIsubjects, aged10to 15,whohadcompleted phase1orobservation inarandom- izedclinical trial (RCT). Foreachsubject, video orthodontic records, aquestionnaire, afact sheet, andacephalometric tra- cing weresenttofive randomly selected reviewing orthodon- tists blinded tosubject groupandstudy purpose. Reviewing orthodontists wereaskedtoassess treatment need, general approach, needforextractions, priority, difficulty, anddeter- minants. Orthodontists agreed highly ontreatment need(95%) andmoderately ontreatment approach (84%) andextraction need(80%). Theydidnotperceive differences inneed, approach, orextractions between treated andcontrol groups. Treated subjects werejudged asless difficult (p=0.0001) and tohavealower treatment priority (p=0.0001) thancontrols. Inranking problems that affect treatment decisions, theortho- dontists ranked dental Class II(p=0.005) andskeletal rela- tionships (p= 0.004) morehighly incontrol thanintreated patients. Thesedataindicate thatorthodontists donotper- ceive phase 1treatment forClass IIaspreventing theneedfor asecond phase orasoffering anyparticular advantage with respect topreventing theneedforextractions orother skeletal treatments inthat second phase. Theydoviewearly Class II treatment asaneffective meansofreducing thedifficulty of andpriority forphase 2.

Objective: To propose a better statistical method of predicting postsurgery soft tissue response in Class II patients.Materials and Methods: The subjects comprise 80 patients who had undergone surgical correction of severe Class II malocclusions. Using 228 predictor and 64 soft tissue response variables, we applied two multivariate methods of forming prediction equations, the conventional ordinary least squares (OLS) method and the partial least squares (PLS) method. After fitting the equation, the bias and a mean absolute prediction error were calculated. To evaluate the predictive performance of the prediction equations, a leave-one-out cross-validation method was used.Results: The multivariate PLS method provided a significantly more accurate prediction than the conventional OLS method.Conclusion: The multivariate PLS method was more satisfactory than the OLS method in accurately predicting the soft tissue profile change after surgical correction of severe Class II malocclusions.

Introduction: The management of patients with Class II malocclusion has been an ongoing discussion in orthodontics. The aim of this study was to determine whether orthodontists agree among themselves and with each other about the etiology, timing, and difficulty of treating subjects with Class II malocclusion. Methods: The initial records of 159 Class II subjects were sent to 8 orthodontists. In this sample, duplicate records of 18 subjects were dispersed. A questionnaire was sent with the records. Results: The intrarater consistency values were 65% when determining the type of malocclusion, 60% when deciding which arch was at fault, and 81% when determining the need for immediate treatment. Consistency values were 33% regarding case difficulty and 77% regarding phase 2 treatment need. There was a significant negative correlation between the consistency of the orthodontists' responses and the peer assessment rating score. Conclusions: We found that practitioners had only moderate agreement among themselves when diagnosing a patient's type of malocclusion and which arch was at fault when a skeletal discrepancy was noted. Intrarater agreement improved as the peer assessment rating score increased, but the correlation was weak, and this was not consistent for all examiners. Because of insufficient intrarater agreement, interrater agreement was not examined. (Am J Orthod Dentofacial Orthop 2012;141:17-23)

Purpose: To propose a more accurate method to predict the soft tissue changes after orthognathic surgery.Patients and Methods: The subjects included 69 patients who had undergone surgical correction of Class III mandibular prognathism by mandibular setback. Two multivariate methods of forming prediction equations were examined using 134 predictor and 36 soft tissue response variables: the ordinary least-squares (OLS) and the partial least-squares (PLS) methods. After fitting the equation, the bias and a mean absolute prediction error were calculated. To evaluate the predictive performance of the prediction equations, a 10-fold cross-validation method was used.Results: The multivariate PLS method showed significantly better predictive performance than the conventional OLS method. The bias pattern was more favorable and the absolute prediction accuracy was significantly better with the PLS method than with the OLS method.Conclusions: The multivariate PLS method was more satisfactory than the conventional OLS method in accurately predicting the soft tissue profile change after Class III mandibular setback surgery. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:e553-e562, 2012

Clear aligners provide a convenient model to measure orthodontic tooth movement (OTM). We examined the role of in vivo aligner material fatigue and subject-specific factors in tooth movement. Fifteen subjects seeking orthodontic treatment at the University of Florida were enrolled. Results were compared with data previously collected from 37 subjects enrolled in a similar protocol. Subjects were followed prospectively for eight weeks. An upper central incisor was programmed to move 0.5 mm. every two weeks using clear aligners. A duplicate aligner was provided for the second week of each cycle. Weekly polyvinyl siloxane (PVS) impressions were taken, and digital models were fabricated to measure OTM. Initial and final cone beam computed tomography (CBCT) images were obtained to characterize OTM. Results were compared to data from a similar protocol, where subjects received a new aligner biweekly. No significant difference was found in the amount of OTM between the two groups, with mean total OTM of 1.11 mm. (standard deviation (SD) 0.30) and 1.07 mm. (SD 0.33) for the weekly aligner and biweekly control groups, respectively (P = 0.72). Over eight weeks, in two-week intervals, material fatigue does not play a significant role in the rate or amount of tooth movement.

Introduction: Moving teeth rapidly and avoiding posttreatment relapse are fundamental goals of orthodontic treatment. In-vitro and animal studies suggest that the human hormone relaxin might increase the rate of movement and the stability through its effect on the periodontal ligament. The purpose of this study was to compare relaxin and a placebo with regard to tooth movement and stability in human subjects. Methods: A single-center, blinded, placebo-controlled, randomized clinical trial was used to examine the effect of relaxin on tooth movement and stability. Forty subjects were randomized 1: 1 and received weekly injections of 50 mu g of relaxin or a placebo for 8 weeks. Aligners programmed to move a target tooth 2 mm during treatment were dispensed at weeks 0, 2, 4, and 6. Movement was measured weekly on polyvinyl siloxane impressions that were scanned and digitized. The subjects were followed through week 12 to assess relapse. Results: Tooth movement over the 8-week treatment period did not differ by treatment group (P - 0.995). By using an intent-to-treat analysis, we found that the mean tooth movement for both groups was 0.83 mm (SE, 0.08 for relaxin and 0.09 for the placebo). Relapse from weeks 8 to 12 was the same in both groups (P = 0.986), and the mean was -0.75 (SE, 0.07 for relaxin and 0.08 for theplacebo). Conclusions: No differences in tooth movement over 8 weeks of treatment or relapse at 4 weeks posttreatment were detected when comparing subjects who received weekly injections of relaxin with those who received a placebo. In both groups, an average of less than half of the programmed tooth movement was obtained after 8 weeks of treatment. The local doses of relaxin might have been too low to affect tooth movement or short-term relapse. (Am J Orthod Dentofacial Orthop 2012;141:196-203)

Chapter 34 Clear Aligners Daljit S. Gill BDS (Hons), BSc (Hons), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), Daljit S. Gill BDS (Hons), BSc (Hons), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.)Search for more papers by this authorFarhad B. Naini BDS (Lond.), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), GCAP (KCL), FHEA, Farhad B. Naini BDS (Lond.), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), GCAP (KCL), FHEASearch for more papers by this author Daljit S. Gill BDS (Hons), BSc (Hons), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), Daljit S. Gill BDS (Hons), BSc (Hons), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.)Search for more papers by this authorFarhad B. Naini BDS (Lond.), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), GCAP (KCL), FHEA, Farhad B. Naini BDS (Lond.), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), GCAP (KCL), FHEASearch for more papers by this author Book Editor(s):Daljit S. Gill BDS (Hons), BSc (Hons), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), Daljit S. Gill BDS (Hons), BSc (Hons), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.)Search for more papers by this authorFarhad B. Naini BDS (Lond.), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), GCAP (KCL), FHEA, Farhad B. Naini BDS (Lond.), MSc (Lond.), FDS RCS (Eng.), MOrth RCS (Eng.), FDS (Orth) RCS (Eng.), GCAP (KCL), FHEASearch for more papers by this author First published: 30 September 2011 https://doi.org/10.1002/9781118785041.ch34 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Orthodontics: Principles and Practice RelatedInformation

Introduction: Our objective was too assess the effectiveness of 3 analgesics (ibuprofen, naproxen sodium, and acetaminophen) and a placebo administered before and after the placement of separators in reducing the severity of postseparator placement pain. We also examined the impact of treatment on chewing efficiency at 24 hours after separator placement. Methods: Twenty-four subjects participated in the study. Each subject received 3 of 4 treatments: ibuprofen, naproxen sodium, acetaminophen, or placebo in random order at monthly intervals. The dosing times were 1 hour before separator placement and 3 and 7 hours after separator placement. Before placement, the subjects completed a masticatory efficiency test and a visual analog scale (VAS) for expected pain and pain experienced. A VAS pain diary was kept for 24 hours. Subjects returned to the clinic after 1 week for separator removal. Results: VAS pain summary scores after separator placement were significantly affected by the administration of ibuprofen (P = 0.0298) and the time after separator placement (P < 0.0001). Administering ibuprofen before and after separator placement significantly reduced pain compared with the placebo. The analgesic effects diminished by day 2, resulting in peak pain levels and decreased chewing efficiency. The expected pain after separator placement also played a role in experienced pain; subjects expecting more pain experienced more pain. Conclusions: Ibuprofen was superior to the placebo in relieving postseparator pain as measured by the VAS pain summary scores, whereas acetaminophen and naproxen sodium did not significantly differ from the placebo. (Am J Orthod Dentofacial Orthop 2011; 139:e53-e58)

Introduction: The aim of this study was to propose a method to classify dental arch forms of subjects with normal occlusion into several types that can ensure both goodness of fit and clinical application. Methods: We selected 306 subjects with normal occlusion from 15,836 young adults, recorded 14 reference points that defined the distance between 2 arch forms as the area between 2 arches, and then classified the dental arch forms by using the partitioning around medoids clustering and silhouette method. We measured tooth size, arch width, basal arch width, arch depth, mesiodistal angulations, and buccolingual inclinations. Results: We identified 3 types of arch forms, and cross-classification of the maxillary by mandibular arch forms showed a more frequent distribution in the diagonal elements than in the off-diagonal elements. The 3 arch forms showed differences in tooth size, arch width, basal arch width, and inclination of the posterior teeth. Conclusions: By defining area discrepancies as distance measures and applying them to the cluster method by using medoids, the dental arch form can be classified keeping control for the extremes without bias. It is hoped that this method will have possible clinical applications in determining the shape and number of preformed orthodontic arch forms. (Am J Orthod Dentofacial Orthop 2011;140:87-96)