Search

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.

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.

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.

OBJECTIVE: The aim of this randomized clinical trial was to evaluate the dental, dentoalveolar, and skeletal changes occurring right after the rapid maxillary expansion (RME) and slow maxillary expansion (SME) treatment using Haas-type expander. METHODS: All subjects performed cone-beam computed tomography (CBCT) before installation of expanders (T1) and right after screw stabilization (T2). Patients who did not follow the research parameters were excluded. The final sample resulted in 21 patients in RME group (mean age of 8.43 years) and 16 patients in SME group (mean age of 8.70 years). Based on the skewness and kurtosis statistics, the variables were judged to be normally distributed and paired t-test and student t-test were performed at significance level of 5%. RESULTS: Intermolar angle changed significantly due to treatment and RME showed greater buccal tipping than SME. RME showed significant changes in other four measurements due to treatment: maxilla moved forward and mandible showed backward rotation and, at transversal level both skeletal and dentoalveolar showed significant changes due to maxillary expansion. SME showed significant dentoalveolar changes due to maxillary expansion. CONCLUSIONS: Only intermolar angle showed significant difference between the two modalities of maxillary expansion with greater buccal tipping for RME. Also, RME produced skeletal maxillary expansion and SME did not. Both maxillary expansion modalities were efficient to promote transversal gain at dentoalveolar level. Sagittal and vertical measurements did not show differences between groups, but RME promoted a forward movement of the maxilla and backward rotation of the mandible. RESUMO OBJETIVO: o objetivo do presente ensaio clínico randomizado foi avaliar as transformações dentárias, dentoalveolares e ósseas que ocorrem imediatamente após o tratamento com expansão rápida da maxila (ERM) e lenta (ELM) usando expansores do tipo Haas. MÉTODOS: todos os indivíduos foram submetidos a tomografias computadorizadas de feixe cônico (TCFC) antes da colocação dos expansores (T1) e imediatamente após a estabilização do parafuso (T2). Os pacientes que não seguiram os parâmetros da pesquisa foram excluídos. A amostra final constou de 21 pacientes no grupo ERM (idade média de 8,43 anos) e 16 no grupo ELM (idade média de 8,7 anos). Com base em estatística de assimetria e curtose, as variáveis foram consideradas de distribuição normal, e os testes t pareado e t de Student foram realizados, com nível de significância de 5%. RESULTADOS: o ângulo intermolares mudou significativamente devido ao tratamento, e o grupo ERM apresentou maior inclinação vestibular do que o grupo ELM. O grupo ERM mostrou alterações significativas em outras quatro medidas devido ao tratamento: a maxila apresentou deslocamento anterior e a mandíbula, rotação posterior; no nível transversal, houve tanto alterações ósseas quanto dentoalveolares significativas, devido à expansão maxilar. O grupo ELM apresentou alterações significativas devido à expansão maxilar. CONCLUSÕES: apenas o ângulo intermolares apresentou diferença significativa entre as duas modalidades de expansão maxilar, com maior inclinação vestibular no grupo ERM. A ERM resultou, também, em expansão maxilar óssea, ao contrário da ELM. As duas modalidades de expansão maxilar promoveram, de forma eficiente, um ganho transversal em nível dentoalveolar. As medidas sagitais e verticais não apresentaram diferenças entre os grupos, mas a ERM promoveu o deslocamento anterior da maxila e a rotação posterior da mandíbula.

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.

Made available in DSpace on 2015-08-06T16:14:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-01-01. Added 1 bitstream(s) on 2015-08-06T16:44:26Z : No. of bitstreams: 1 S2176-94512014000100019.pdf: 212204 bytes, checksum: b284b5b63ba9f451049d7874185b5f28 (MD5) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) INTRODUÇÃO:devido ao número reduzido de estudos que distinguem entre as mudanças dentoalveolares e ósseas produzidas pelo aparelho de Thurow, esse estudo clínico, conduzido pelo departamento de Ortodontia da Faculdade de Odontologia de Araraquara, foi proposto para avaliar as mudanças dentárias e esqueléticas induzidas pelo aparelho de Thurow modificado.MÉTODOS:a amostra incluiu um grupo experimental de 13 indivíduos, entre 7 e 10 anos de idade, com má oclusão Classe II e mordida aberta anterior, e um grupo controle de 22 indivíduos, com idades, plano mandibular e má oclusão similares. Com base em 14 pontos cefalométricos, 8 ângulos (S-N-ANS, SNA, PPA, S-N-Pog, SNB, MPA, PP/MPA, ANB) e 3 medidas lineares (N-Me, ANS-Me, S-Go), foram avaliados movimentos maxilares e mandibulares horizontais e verticais dentários e esqueléticos (ANS, PNS, U1, U6, Co, Go, Pog, L1, L6).RESULTADOS:o tratamento produziu diminuição significativamente maior no ângulo entre o plano palatino e o plano mandibular do grupo controle, devido ao aumento do ângulo do plano palatino. Os ângulos A-N-B, S-N-A e S-N-ANS diminuíram significativamente mais no grupo tratado. A PNS sofreu remodelação superior. A altura facial inferior (ANS-Me) diminuiu no grupo tratado, ao passo que aumentou no grupo controle.CONCLUSÕES:o aparelho controlou deslocamento vertical e horizontal da maxila, rotacionou a maxila para melhorar a mordida aberta e diminuiu a altura facial inferior. INTRODUCTION:Due to the lack of studies that distinguish between dentoalveolar and basal changes caused by the Thurow appliance, this clinical study, carried out by the School of Dentistry - State University of São Paulo/Araraquara, aimed at assessing the dental and skeletal changes induced by modified Thurow appliance.METHODS:The sample included an experimental group comprising 13 subjects aged between 7 and 10 years old, with Class II malocclusion and anterior open bite, and a control group comprising 22 subjects similar in age, sex and mandibular plane angle. Maxillary/mandibular, horizontal/vertical, dental/skeletal movements (ANS, PNS, U1, U6, Co, Go, Pog, L1, L6) were assessed, based on 14 landmarks, 8 angles (S-N-ANS, SNA, PPA, S-N-Pog, SNB, MPA, PP/MPA, ANB) and 3 linear measures (N-Me, ANS-Me, S-Go).RESULTS:Treatment caused significantly greater angle decrease between the palatal and the mandibular plane of the experimental group, primarily due to an increase in the palatal plane angle. ANB, SNA and S-N-ANS angles significantly decreased more in patients from the experimental group. PNS was superiorly remodeled. Lower face height (ANS-Me) decreased in the experimental group and increased in the control group.CONCLUSIONS:The modified Thurow appliance controlled vertical and horizontal displacements of the maxilla, rotated the maxilla and improved open bite malocclusion, decreasing lower facial height. Texas A&M Baylor College of Dentistry State University of São Paulo School of Dentistry Texas A&M Baylor College of Dentistry Department of Orthodontics

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.

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.