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Objectives To identify schematic relationships between root canal axis, the cementoenamel junction (CEJ), and the contour of the clinical crown’s facial surface in maxillary central incisors. Materials and Methods 72 radiographic images of extracted maxillary central incisors with previous root canal treatment were collected. Angles (tangent angle) between the root canal axis and lines tangent to fiducial points on the facial surface 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, and 5.5 mm cervical to the incisal edge were measured using ImageJ software. Facial-palatal CEJ widths were measured and divided into facial and palatal CEJ by the root canal axis. Generalized linear models were used to assess any relationship between CEJ widths and the constructed tangent angles. The Paired Difference T-test was performed to determine the ratio of palatal CEJ to facial CEJ widths. Results The correlation between CEJ width and angle measurements was statistically significant except at 3.5 mm (P < .05). The tangent angle values decreased from the most incisal point (22.8°) to the most cervical point (18.4°). The average value of total CEJ widths was 7.44 mm. Palatal CEJ was on average 0.22 mm greater than facial CEJ widths (P = 1.61e-6). Conclusions Using CEJ width and tangent angle of fiducial point, the root canal axis of the maxillary central incisor can be predicted. Clinical relevance Crown morphology can be applied to design a standardized endodontic access stent to aid in root canal therapy in maxillary central incisors when the canal is difficult to identify.

Made available in DSpace on 2021-06-25T12:30:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Introduction: Computer-aided design and manufacturing (CAD-CAM) systems have assisted orthodontists to position brackets virtually. The purpose of this study was to evaluate if a CAD-CAM system could predict the orthodontic treatment outcome of patients with Angle Class I malocclusion with mild crowding or spacing and with no need for orthodontic extraction. Methods: Using the American Board of Orthodontics Cast-Radiograph Evaluation (ABO-CRE) and color map superimposition, the treated occlusion was compared with the virtual final occlusion of 24 young adults with Class I occlusion. Using eXceed software (eXceed, Witten, Germany), we created the final occlusion prediction for each patient (virtual set up group). A digital model of the final occlusion of each patient was created (treated occlusion group). ABO-CRE score was used to compare groups. In addition, a color map was created for all subjects to access the mean and range values between the virtual set up model and treated occlusion model of each patient. Random and systematic errors were calculated. In addition, chi-square and t test were used. Results: Comparisons between virtual set up occlusion and treated occlusion showed statistically significant differences in 3 out of 7 measurements: interproximal contact score was larger for treated than virtual occlusion (0.45 mm and 0.04 mm, respectively), and the treated occlusion showed larger values than the virtual occlusion for occlusal contacts (14.13 mm and 7.62 mm, respectively) and overjet (7.37 mm and 0.66 mm, respectively). Although the treated occlusion showed a larger score than the virtual occlusion (50.41 mm and 34.58 mm, respectively), there is no significant difference between both. Root angulation decreased (from 1.95 +/- 1.29 to 0.65 +/- 0.71) because of the treatment. Conclusion: ABO-CRE overall score presents no difference between groups. In addition, CAD-CAM setup occlusion closely predicts the final teeth alignment and leveling with interarch relationships showing less ABO-CRE score deduction. Sao Paulo State Univ, Sch Dent, Dept Dent Mat & Prosthodont, Araraquara, SP, Brazil Sao Paulo State Univ, Inst Chem, Dept Phys Chem, Araraquara, SP, Brazil Univ Texas Hlth Sci Ctr Houston, Sch Dent, Dept Orthodont, 7500 Cambridge St,Ste 5130, Houston, TX 77030 USA Sao Paulo State Univ, Sch Dent, Dept Dent Mat & Prosthodont, Araraquara, SP, Brazil Sao Paulo State Univ, Inst Chem, Dept Phys Chem, Araraquara, SP, Brazil CNPq: 168131/2017-0

PURPOSE: One critical step in routine orthognathic surgery is to reestablish a desired final dental occlusion. Traditionally, the final occlusion is established by hand articulating stone dental models. To date, there are still no effective solutions to establish the final occlusion in computer-aided surgical simulation. In this study, we consider the most common one-piece maxillary orthognathic surgery and propose a three-stage approach to digitally and automatically establish the desired final dental occlusion. METHODS: The process includes three stages: (1) extraction of points of interest and teeth landmarks from a pair of upper and lower dental models; (2) establishment of Midline-Canine-Molar (M-C-M) relationship following the clinical criteria on these three regions; and (3) fine alignment of upper and lower teeth with maximum contacts without breaking the established M-C-M relationship. Our method has been quantitatively and qualitatively validated using 18 pairs of dental models. RESULTS: Qualitatively, experienced orthodontists assess the algorithm-articulated and hand-articulated occlusions while being blind to the methods used. They agreed that occlusion results of the two methods are equally good. Quantitatively, we measure and compare the distances between selected landmarks on upper and lower teeth for both algorithm-articulated and hand-articulated occlusions. The results showed that there was no statistically significant difference between the algorithm-articulated and hand-articulated occlusions. CONCLUSION: The proposed three-stage automatic dental articulation method is able to articulate the digital dental model to the clinically desired final occlusion accurately and efficiently. It allows doctors to completely eliminate the use of stone dental models in the future.

Purpose A facial reference frame is a 3-dimensional Cartesian coordinate system that includes 3 perpendicular planes: midsagittal, axial and coronal. The order in which one defines the planes matters. The purposes of this study were to determine: 1) what sequence (axial-midsagittal-coronal versus midsagittal-axial-coronal) produced more appropriate reference frames, and 2) whether orbital or auricular dystopia influenced the outcomes. Materials and Methods This was an ambispective cross-sectional study. Fifty-four subjects with facial asymmetry were included. The facial reference frames of each subject (outcome variable) were constructed using 2 methods (independent variable): axial-plane-first and midsagittal plane-first. Two board-certified orthodontists together blindly evaluated the results using a 3-point categorical scale based on their careful inspection and expert intuition. The covariant for stratification was the existence of orbital or auricular dystopia. Finally, Wilcoxon signed rank tests were performed. Results The facial reference frames defined by the midsagittal plane-first method was statistically significantly different from ones defined by the axial-plane-first method (P=0.001). Using midsagittal plane-first method, the reference frames were more appropriately defined in 22 (40.7%) subjects, equivalent in 26 (48.1%) and less appropriately defined in 6 (11.1%). After stratified by orbital or auricular dystopia, the results also showed that the reference frame computed using midsagittal plane-first method was statistically significantly more appropriate in both subject groups regardless of the existence of orbital or auricular dystopia (27 with orbital or auricular dystopia and 27 without, both P Conclusion The midsagittal plane-first sequence improves the facial reference frames compared with the traditional axial-plane-first approach. However, regardless of the sequence used, clinicians need to judge the correctness of the reference frame prior to diagnosis or surgical planning.

Objectives: To investigate the canine retraction rate and anchorage loss during canine retraction using self-ligating (SL) brackets and conventional (CV) brackets. Differences between maxillary and mandibular rates were computed. Materials and Methods: Twenty-five subjects requiring four first premolar extractions were enrolled in this split-mouth, randomized clinical trial. Each patient had one upper canine and one lower canine bonded randomly with SL brackets and the other canines with CV brackets but never on the same side. NiTi retraction springs were used to retract canines (100 g force). Maxillary and mandibular superimpositions, using cephalometric 45° oblique radiographs at the beginning and at the end of canine retraction, were used to calculate the changes and rates during canine retraction. Paired t-tests were used to compare side and jaw effects. Results: The SL and CV brackets did not show differences related to monthly canine movement in the maxilla (0.71 mm and 0.72 mm, respectively) or in the mandible (0.54 mm and 0.60 mm, respectively). Rates of anchorage loss in the maxilla and in the mandible also did not show differences between the SL and CV brackets. Maxillary canines showed greater amount of tooth movement per month than mandibular canines (0.71 mm and 0.57 mm, respectively). Conclusions: SL brackets did not show faster canine retraction compared with CV brackets nor less anchorage loss. The maxillary canines showed a greater rate of tooth movement than the mandibular canines; however, no difference in anchorage loss between the maxillary and mandibular posterior segments during canine retraction was found.

Aim The purpose of this article was to report the orthodontic treatment of a growing patient with Angle Class II malocclusion, without teeth extraction and/or orthognathic surgery. Methods The Herbst mandibular protractor, associated with miniscrew implants (MSIs) installed in the mandible, was used for the correction of Class II malocclusion. The use of skeletal anchorage was aimed to reduce lower incisor proclination. Results Restriction of maxillary growth, distalization of maxillary molars, and control of the lower incisor proclination were observed. Conclusion The association of MSIs with mandibular protractor device allowed minimization of side effects as well as enhancement of skeletal and dental effects with excellent predictability and minimal patient collaboration.

Fabrication of orthodontic aligners directly via 3-dimensional (3D) printing presents the potential to increase the efficiency of aligner production relative to traditional workflows; however tunable aspects of the 3D-printing process might affect the dimensional fidelity of the fabricated appliances. This study aimed to investigate the effect of print orientation on the dimensional accuracy of orthodontic aligners printed directly with a 3D printer.A digitally designed aligner of 500 μm thickness was printed in 3D in Grey V4 (Formlabs, Somerville, Mass) resin at 8 angulations at 45° intervals (n = 10 per angulation) using a stereolithography 3D printer. Each aligner was scanned with an optical scanner, and all but the intaglio surface of each scan was digitally removed. Each resultant scan file was superimposed onto the isolated intaglio of the designed master aligner file. The dimensional deviation was quantified with Geomagic Control software (3D Systems, Rock Hill, SC), and data were analyzed using R statistical software (version 2018; R Core Team, Vienna, Austria) (P 0.05).Print angle showed a statistically significant effect on standard deviation, average positive deviation, absolute average negative deviation, and percentage of points out of bounds (tolerance bounds defined as ±250 μm) (P 0.05). Qualitative analysis of the 3D surface deviation maps indicated that the 0° and 90° groups showed less deviation and appeared to be the most accurate in the anterior regions. Overall, the majority of the print angle groups studied were not printed within clinically acceptable tolerance ranges, with the major exception being the 90° group, which printed nominally within clinically acceptable tolerance ranges.With the workflow applied, print orientation significantly affects the dimensional accuracy of directly 3D-printed orthodontic aligners. Within the limitations of this study, printing at the 90° angulation would be advised as it is the group with the most accurate prints relative to the 7 other orientations investigated, although not all differences were statistically significant.

Objective: To evaluate differences in discomfort levels between patients treated with aligners and traditional fixed orthodontic appliances. Materials and Methods: This blinded, prospective, randomized equivalence two-arm parallel trial allocated 41 adult Class I nonextraction patients to either traditional fixed appliance (6 males and 12 females) or aligner (11 males and 12 females) treatment. Patients completed daily discomfort diaries following their initial treatment appointment, after 1 month and after 2 months. They recorded their levels of discomfort at rest, while chewing, and while biting, as well as their analgesic consumption and sleep disturbances. Results: Both treatment modalities demonstrated similar levels of initial discomfort. There were no significant sex differences. Patients in the traditional fixed appliances group reported significantly (P < .05) greater discomfort than patients in the aligner group during the first week of active treatment. There was significantly more discomfort while chewing than when at rest. Traditional patients also reported significantly more discomfort than aligner patients after the first and second monthly adjustment appointments. Discomfort after the subsequent adjustments was consistently lower than after the initial bonding or aligner delivery appointments. A higher percentage of patients in the fixed-appliance group reported taking analgesics during the first week for dental pain, but only the difference on day 2 was statistically significant. Conclusions: Patients treated with traditional fixed appliances reported greater discomfort and consumed more analgesics than patients treated with aligners. This trial was not registered.

OBJECTIVES: To investigate the canine retraction rate and anchorage loss during canine retraction using self-ligating (SL) brackets and conventional (CV) brackets. Differences between maxillary and mandibular rates were computed. MATERIALS AND METHODS: Twenty-five subjects requiring four first premolar extractions were enrolled in this split-mouth, randomized clinical trial. Each patient had one upper canine and one lower canine bonded randomly with SL brackets and the other canines with CV brackets but never on the same side. NiTi retraction springs were used to retract canines (100 g force). Maxillary and mandibular superimpositions, using cephalometric 45° oblique radiographs at the beginning and at the end of canine retraction, were used to calculate the changes and rates during canine retraction. Paired t-tests were used to compare side and jaw effects. RESULTS: The SL and CV brackets did not show differences related to monthly canine movement in the maxilla (0.71 mm and 0.72 mm, respectively) or in the mandible (0.54 mm and 0.60 mm, respectively). Rates of anchorage loss in the maxilla and in the mandible also did not show differences between the SL and CV brackets. Maxillary canines showed greater amount of tooth movement per month than mandibular canines (0.71 mm and 0.57 mm, respectively). CONCLUSIONS: SL brackets did not show faster canine retraction compared with CV brackets nor less anchorage loss. The maxillary canines showed a greater rate of tooth movement than the mandibular canines; however, no difference in anchorage loss between the maxillary and mandibular posterior segments during canine retraction was found.

Accurately establishing a desired final dental occlusion of the upper and lower teeth is a critical step in orthognathic surgical planning. Traditionally, the final occlusion is established by hand-articulating the stone dental models. However, this process is inappropriate to digitally plan the orthognathic surgery using computer-aided surgical simulation. To date, there is no effective method of digitally establishing final occlusion. We propose a 3-stage approach to digitally and automatically establish a desired final dental occlusion for 1-piece maxillary orthognathic surgery, including: (1) to automatically extract points of interest and four key teeth landmarks from the occlusal surfaces; (2) to align the upper and lower teeth to a clinically desired Midline-Canine-Molar relationship by minimization of sum of distances between them; and (3) to finely align the upper and lower teeth to a maximum contact with the constraints of collision and clinical criteria. The proposed method was evaluated qualitatively and quantitatively and proved to be effective and accurate.

This experimental study was designed to (1) produce buccal translation of maxillary premolars and (2) evaluate the effects on the buccal alveolar bone.A randomized split-mouth study was designed based on 7 adult male beagle dogs. The experimental side received a custom cantilever appliance fabricated to produce a translatory force through the maxillary second premolar's center of resistance. The contralateral second premolar received no appliance and served as the control. The premolars underwent 6-7 weeks of buccal translation, followed by 3 weeks of fixed retention. Biweekly tooth movements were evaluated using intraoral and radiographic measurements. Pretreatment and posttreatment models were measured to assess tipping. Three-dimensional microscopic tomography was used to quantify the amount and density of buccal bone. Bone formation and turnover were assessed using fluorescent labeling, hematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, and bone sialoprotein immunostaining.The applied force (100 g of force) translated (1.4 mm) and minimally tipped (4°) the experimental teeth. Lateral translation produced dehiscences at the mesial and distal roots, with 2.0 mm and 2.2 mm loss of vertical bone height, respectively. Bone thickness decreased significantly (P 0.05) at the apical (∼0.4 mm), midroot (∼0.4 mm), and coronal (∼0.2 mm) levels. Fluorescent imaging, hematoxylin and eosin staining, and immunostaining for bone sialoprotein all showed new bone formation extending along the entire periosteal surface of the second premolar's buccal plate. Tartrate-resistant acid phosphatase staining demonstrated greater osteoclastic activity on the experimental than that of control sections.New buccal bone forms on the periosteal surface during and after tooth translation, but the amount of bone that forms is less than the amount of bone loss, resulting in a net decrease in buccal bone thickness and a loss of crestal bone.

Orthodontists have long been aware that mandibular rotation takes place during growth, but most have underestimated its importance. This is so because the distinction between the true rotation and the rotation of the mandibular plane is typically not made. Traditionally, orthodontists have focused on the mandibular plane, which changes little because modeling on the lower mandibular border largely hides the true rotation that occurs. Furthermore, orthodontists must understand that changes in tooth position—over which they have great control—play an important role in determining the true rotational changes that occur. Such an appreciation is of particular importance when evaluating Class II cases, for which true rotation is critically important, in terms of both the development and solution of the problem. Clinically, they must be aware of and able to use the various centers of rotation to prevent deleterious changes from occurring and to orthopedically correct the problems that have developed. Orthodontists must understand that true rotation is the primary determinant of chin position and a major determinant of condylar growth direction, mandibular modeling, and dentoalveolar compensations. They must learn how to take advantage of the mandible's capacity to adapt to rotational changes.

Due to the skeletal complexity of the problem, hyperdivergent retrognathic patients are among the most difficult for orthodontists to treat. It is imperative to treat these patients for both esthetic and functional reasons. Hyperdivergent growth patterns are generally established early and most do not improve over time. The etiology appears to be environmental, due to postural adjustments related with compromised airways and weak masticatory musculature. If a lowered mandible posture is maintained in growing subjects, the dentition, dentoalveolar complex, and the mandible should be expected to compensate. Dentoalveolar heights should be expected to be excessive (i.e., supraeruption of the teeth), the ramus is shorter, the gonial angle is larger, the mandibular symphysis is taller and thinner, the mandibular plane is steeper, the mandible is retrognathic, and anterior lower face height is increased. Moreover, the jaws, especially the upper, are narrow. The most important factor underlying these developmental adaptations is true mandibular rotation. Rotation is important because it is the major determinant of the anteroposterior (AP) chin position. The detrimental skeletal changes that characterize hyperdivergent patients are ultimately due to backward or less than average true forward rotation. Theoretically, a therapeutic treatment that mimics normal growth (i.e., one that builds in true forward rotation) is desirable because it might be expected to correct not only the anteroposterior (AP) and vertical position of the chin, but also many of the other morphological maladaptations associated with the hyperdivergent retrognathic phenotype.

This article describes the orthodontic treatment of a young adult with a skeletal Class III malocclusion. The treatment consisted of mandibular molar distalization using miniscrew implants (MSIs). MSIs were placed between the mandibular second premolars and mandibular first molars. Mandibular molars were distalized using open nickel-titanium coil springs, and indirect anchorage was provided by the MSIs. The lower anterior segment was distalized with direct anchorage using closed nickel-titanium coil springs and the same MSIs. The active treatment period was 28 months (it took 4 months to distalize the lower molars). Normal occlusion was obtained and facial balance was improved.

Background: The aim of this study was to determine if miniscrew implants (MSIs) can be used to control vertical development and improve the facial profile of Class II growing hyperdivergent patients. Methods: The sample includes 18 hyperdivergent patients (12.3 � 1.8 years of age) who were consecutively treated using MSIs to intrude the maxillary and mandibular molars. They were matched to untreated controls based on age, sex, and the mandibular plane angle. Lateral cephalograms were taken immediately before and after treatment (2.5 � 0.9 years treatment duration). Growth and treatment changes of 11 linear and angular measurements, as well as the horizontal and vertical movements of 6 landmarks, were described using cranial base, maxillary, and mandibular superimpositions. Results: The upper molars of the treated patients were held in place vertically (0.3 mm), whereas they erupted significantly in the control group (1.5 mm). In contrast, the lower molars erupted significantly more (1.8 mm) in the treated patients than control group. The sella-nasion-pogonion and sella-nasion-B angles increased significantly more (0.5 � and 0.7� , respectively) in the treated patients than in the control

Introduction Because of limited available reference data, this study described the vertical growth changes that occur in untreated adolescents 10 to 15 years of age and evaluated the validity of measurements commonly used to classify patients’ vertical growth tendencies. Methods The sample consisted of 228 subjects (119 boys, 109 girls) between 10 and 15 years of age with normal occlusions or malocclusions who had lateral cephalograms (n = 1303) taken annually. Based on 6 landmarks, 3 angles (PPA, MPA, PP/MPA) and 2 proportions (PFH:AFH and UFH:LFH) were calculated. To reduce errors, each subject’s growth curve was estimated by using multilevel modeling procedures, and the estimated values were analyzed. Results Growth changes between 10 and 15 years for each of the 5 measurements followed relatively simple (linear or quadratic) polynomial models. On average, PPA and PFH:AFH increased, and MPA and PP/MPA decreased. The UFH:LFH ratio increased during the first few years and then decreased. MPA, PP/MPA, and PFH:AFH showed moderately high intercorrelations; PPA displayed moderate to moderately low correlations with UFH:LFH; UFH:LFH showed a moderate correlation with PP/MPA. Approximately 75% to 86% of the subjects classified as hyperdivergent or hypodivergent at 10 years maintained their classification. Subjects classified as hyperdivergent at 15 years of age showed significantly greater growth changes than did those classified within normal limits, who, in turn, showed greater changes than did the hypodivergent subjects. Conclusions Measurements typically used to classify vertical growth tendencies changed significantly during adolescence, with boys generally showing greater changes than girls. Although MPA, PFH:AFH, and PP/MPA measured the same phenotypic attribute, PPA and UFH:LFH were relatively independent of the other 3 measurements. Most subjects maintained their vertical facial types, but some worsened, and others improved.

Ingestion of a foreign object, including a dental object, can lead to a trip to the emergency room. This article describes the accidental swallowing of a key that was used to activate a rapid maxillary expander. An orthodontic patient swallowed the key while trying to activate the appliance at home. The object's trajectory was followed on radiographs until it was eliminated. Possible clinical complications, legal implications of this situation, and practices for prevention are described.

INTRODUCTION: Although lip bumpers (LBs) provide significant clinical gain of mandibular arch perimeter in mixed-dentition patients, orthodontists are reluctant to use them due to the possibility of permanent second molar eruptive disturbances.OBJECTIVE: The present study was conducted to assess second molar impaction associated with the use of LBs, and to investigate how they can be solved.MATERIAL AND METHODS: Lateral and panoramic radiographs of 67 patients (34 females and 33 males) were assessed prior (T1) and post-LB treatment (T2). LB therapy lasted for approximately 1.8 ± 0.9 years. Concomitant rapid palatal expansion (RPE) was performed in the maxilla at LB treatment onset. Impaction of mandibular second molars was assessed by means of panoramic radiographs in relation to the position of first mandibular molars. Horizontal and vertical movements of first and second molars were assessed cephalometrically on lateral cephalometric radiographs based on mandibular superimpositions.RESULTS: Eight (11.9%) patients had impacted second molars at the end of LB therapy. Two patients required surgical correction, whereas five required spacers and one patient was self-corrected. Mandibular first molar tip and apex migrated forward 1.3 mm and 2.3 mm, respectively. Second molar tip showed no statistically significant horizontal movement.CONCLUSION: Although LB therapy increased the risk of second molar impaction, impactions were, in most instances, easily solved. INTRODUÇÃO: embora placas labioativas (PLAs) promovam um ganho clínico significativo no perímetro da arcada inferior em pacientes com dentição mista, ortodontistas são relutantes em usá-las devido a possibilidade de problemas eruptivos dos segundos molares.OBJETIVO: o presente estudo avaliou a impacção dos segundos molares associada ao uso das PLAs e como a impacção pôde ser resolvida.MÉTODOS: radiografias cefalométricas lateral e panorâmica de 67 pacientes (34 do sexo feminino e 33 do masculino) foram avaliadas antes (T1) e após (T2) o tratamento com PLAs, que durou aproximadamente 1,8 ± 0,9 anos. Expansão rápida do palato (ERP) foi usada na maxila no início do uso da PLA. Usando as radiografias panorâmicas, a impacção dos segundos molares inferiores foi avaliada relativamente à posição dos primeiros molares mandibulares. Os movimentos horizontais e verticais dos primeiros e segundos molares inferiores foram avaliados com base em sobreposições de estruturas estáveis da arcada inferior por meio das radiografias laterais.RESULTADOS: oito (11,9%) pacientes apresentaram impacção dos segundos molares mandibulares ao final do tratamento com PLA; dois pacientes tiveram de recorrer à intervenção cirúrgica para a correção da impacção, cinco tiveram a correção da impacção usando apenas espaçadores e um apresentou autocorreção da impacção. A coroa e o ápice do primeiro molar inferior migraram 1.3mm e 2,.3mm, respectivamente, para mesial. O segundo molar não mostrou movimento horizontal significativo.CONCLUSÃO:embora o tratamento com PLA aumente o risco de impacção do segundo molar mandibular, as impacções, na maioria das vezes, podem ser facilmente corrigidas.

SUMMARY The purpose of the study is to determine whether the various aspects of the craniofacial complex exhibit female adolescent growth spur ts. Multilevel polynomial models were used to estimate the growth curves of a mixed-longitudinal sample of 111 untreated females 10–15 years of age. To evaluate the horizontal and vertical movements of the individual landmarks relative to stable structures, the tracings were superimposed on the natural reference structures in the anterior cranial base. The horizontal and vertical growth changes of four landmarks and the changes of three traditional linear measurements were evaluated. Posterior nasal spine (PNS) moved posteriorly at a constant rate of approximately 0.12 mm/ year. Fi ve measures showed changes in growth velocity (i.e. quadratic growth curves) but not adolescent growth spurts, including the anterior movements of anterior nasal spine (ANS) and pogonion (Pg), the inferior movements of gonion (Go), and the increases in ANS–PNS and condylion to pogonion (Co–Pg). Five measurements, including the inferior movements of ANS, PNS and Pg, the posterior movements of Go, and the increases of Go–Pg exhibited adolescent growth spurts. Peak growth velocities were attained between 11.4 and 12.8 years of age, approximately 0.7–1.4 years earlier in the maxilla than mandible. While the vertical aspects of craniofacial growth exhibit distinct female adolescent growth spurts, with peak rates occurring earlier in the maxilla than mandible, most horizontal aspects of craniofacial growth do not exhibit an adolescent spurt.

OBJECTIVE: To systematically review the scientific evidence pertaining to the effectiveness of high-pull headgear in growing Class II subjects. METHODS: A literature survey was performed by electronic database search. The survey covered the period from January 1966 to December 2008 and used Medical Subject Headings (MeSH). Articles were initially selected based on their titles and abstracts; the full articles were then retrieved. The inclusion criteria included growing subjects between 8 to 15 years of age, Class II malocclusion treatment with high-pull headgear, and a control group with Class II malocclusion. References from selected articles were hand-searched for additional publications. Selected studies were evaluated methodologically. RESULTS: Four articles were selected; none were randomized controlled trials. All of the articles clearly formulated their objectives and used appropriate measures. The studies showed that high-pull headgear treatment improves skeletal and dental relationship, distal displacement of the maxilla, vertical eruption control and upper molars distalization. One of the studies showed a slight clockwise rotation of the palatal plane; the others showed no significant treatment effect. The mandible was not affected by the treatment. CONCLUSION: While there is still a lack of strong evidence demonstrating the effects of high-pull headgear with a splint, other studies indicate that the AP relations improve due to distalization of the maxilla and upper molars, with little or no treatment effects in the mandible. Greater attention to the design should be given to improve the quality of such trials. OBJETIVO: fazer uma revisão sistemática das evidências científicas mostrando a efetividade do aparelho extrabucal com cobertura oclusal associado à tração alta em pacientes com má oclusão Classe II em crescimento. MÉTODOS: um levantamento na literatura foi realizado por meio de pesquisa em bancos de dados eletrônicos, cobrindo o período de janeiro de 1966 a dezembro de 2008, utilizando o Medical Subject Headings (MeSH). Inicialmente, a seleção foi baseada em títulos e resumos; após essa etapa, os artigos potencialmente selecionados foram integralmente observados. Os critérios de inclusão apresentaram pacientes em crescimento, entre 8 e 15 anos de idade, má oclusão de Classe II tratada com aparelhos extrabucais com cobertura oclusal e tração alta, tendo grupo controle também com má oclusão de Classe II. Os estudos selecionados foram avaliados metodologicamente. RESULTADOS: quatro artigos foram selecionados. Nenhum foi estudo controlado randomizado. Os artigos claramente formularam seus objetivos e usaram medidas apropriadas. Os estudos mostraram que houve melhora nas relações esqueléticas e dentárias, deslocamento da maxila distalmente, controle da erupção vertical e distalização dos molares superiores. Um estudo mostrou uma suave inclinação horária do plano palatino. A mandíbula não foi afetada. CONCLUSÃO: embora exista falta de forte evidência mostrando os efeitos do aparelho extrabucal com cobertura oclusal, estudos realizados indicaram que a relação anteroposterior melhorou devido à distalização da maxila e dos molares superiores, com pequeno ou nenhum efeito na mandíbula. Uma maior preocupação quanto ao desenho deveria ser dada para melhorar a qualidade de pesquisas com esse tipo de abordagem.