Influence of the maxillary dimensions and anterior teeth anatomy on the buccal impaction of upper permanent canines: A three-dimensional case-control study.

OBJECTIVE: The diagnosis of impacted upper permanent canines (IUPC) is a relatively common clinical finding. The aim of this study was to investigate the association of the buccal impaction of upper permanent canines with their dimensions and the maxilla bone base. MATERIAL AND METHODS: Cone beam computed tomography files of 66 patients were allocated into: impaction group (ICG/n=33/mean age 15.7±3.9 years), with 44 impacted canines by the buccal side; control group (CG/n=33/mean age 15.66±3.99 years), matched for age and sex, with 66 canines normally erupted. The following measurements were obtained from ICG and CG groups: linear and volumetric canine dimensions, linear measurements of upper permanent central and lateral incisors, measurements of the anterior perimeter and transverse segments of the maxilla. Independent Student's t-test was used for intergroup analysis with correction of Bonferroni (α=0,005). RESULTS: Higher values were found in the means of the variables regarding to the anterior teeth crowns in the ICG group, however, without a significant difference (P<0,005). The upper arch anterior perimeter of the individuals with canine impaction through buccal area was reduced compared to CG (P=0.001). CONCLUSIONS: It can be concluded that individuals with upper buccal impacted permanent canine showed a significantly smaller anterior perimeter of the maxillary arch when compared to the control group. Although greater canine mesiodistal diameter was found in this group, there is no statistical association with the occurrence of this condition.

Influence of the maxillary dimensions and lateral incisor anatomy on the palatal impaction of maxillary permanent canines: A three-dimensional case-control study.

OBJECTIVE: The diagnosis of impacted upper permanent canines (IUPC) is a relatively common clinical finding. The aim of this study was to investigate associations between the upper permanent canines palatal impaction, lateral incisors morphology and the maxilla bone base. MATERIAL AND METHODS: Cone-beam tomography files from 62 subjects were divided into 2 groups: impaction group (ICG/n=31; mean age 14.3±2.4) with 45 canines impacted on the palatal side and age- and sex-matched control group (CG/n=31; mean age 14.3±2.3), with 62 normally erupted canines. Linear and volumetric measurements of the lateral incisors, linear transversal measures and the maxillary anterior perimeter were taken. Independent Student's t-test was used for intergroup analysis with correction of Bonferroni. RESULTS: Significant differences were found for crown length and root diameter (buccal-palatal) (P<0.005). The maxillary anterior perimeter in the ICG was reduced in relation to the GC but not significantly (P=0.008). The transverse skeletal variables of the maxilla were equivalent in the intergroup comparison (P>0.005). CONCLUSION: Smaller dimensions in the crown length and in the upper permanent lateral incisors root buccal-palatal diameter were associated with the impaction of upper permanent canines on the palatal side. The maxillary transverse morphology did not show any association with the occurrence of this condition.

Three-dimensional micromorphology of human midpalatal suture and pterygomaxillary articular complex.

BACKGROUND: Sutures exist in the craniofacial area, and the pattern of maturation and synostosis of facial sutures is largely unknown. METHODS: For a comprehensive understanding of the three-dimensional circummaxillary suture micromorphology, human midpalatal suture (MPS) and pterygomaxillary articular complex from eight subjects' (five males, three females, 72-88 years old) autopsies were longitudinally scanned with microcomputed tomography. Additional histology was performed for hematoxylin and eosin staining. Sutural micromorphology was assessed by interdigitation index (II), obliteration index (OI) and obliteration number. Intergroup comparisons were performed with Kruskal-Wallis and Mann-Whitney U with Bonferroni correction (α = 0.005). Correlation with anteroposterior and craniocaudal gradients was assessed with Spearman's correlation test (α = 0.05). RESULTS: Maxillary region of MPS presented a higher II 1.50 (0.61) and obliteration number per slice 8 (9) (P < 0.005). OI was increased in palatomaxillary 35% (47%) followed by pterygopalatine suture 25% (49%) (P < 0.005). The II and OI of the MPS exhibited only a weak anteroposterior gradient, with relatively low correlations. Obliteration areas were found sporadically along the entire MPS. CONCLUSIONS: Based on these findings, it is conceivable that the success of nonsurgical maxillary expansion largely depends on individual variations in sutural morphology and maturation rather than appliance design.

Response of masticatory muscles to treatment with orthodontic aligners: a preliminary prospective longitudinal study.

INTRODUCTION: The emergence of orthodontic aligners has provided an aesthetic and comfortable option for orthodontic treatment. However, the encapsulated design of the aligners can influence the masticatory muscles, and might compromise safe treatment. OBJECTIVE: This preliminary longitudinal study aimed to investigate whether the use of orthodontic aligners affects the biting force and myoelectric activity of the superficial masseter and anterior temporal muscles. METHODS: Ten subjects participated in the study and underwent treatment during an 8-month follow-up period. The root mean square (RMS), the median power frequency (MPF) of the surface electromyography (sEMG) signals, and the biting force (kgf) were recorded and normalized relative to the pretreatment condition. The data were analyzed by repeated-measure analysis of variance (ANOVA), with the significance level set at 5%. RESULTS: Both the superficial masseter and the anterior temporal muscles presented an increase in sEMG signal activity during the treatment, with a marked increase in the latter compared to the former (p<0.05). Moreover, a significant decrease in bite force was evidenced (p<0.05). CONCLUSIONS: This preliminary study observed that the orthodontic aligners affected the muscle recruitment pattern of masticatory muscles, and reduced biting performance during the 8-month follow-up period.

Response of masticatory muscles to treatment with orthodontic aligners: a preliminary prospective longitudinal study

ABSTRACT Introduction: The emergence of orthodontic aligners has provided an aesthetic and comfortable option for orthodontic treatment. However, the encapsulated design of the aligners can influence the masticatory muscles, and might compromise safe treatment. Objective: This preliminary longitudinal study aimed to investigate whether the use of orthodontic aligners affects the biting force and myoelectric activity of the superficial masseter and anterior temporal muscles. Methods: Ten subjects participated in the study and underwent treatment during an 8-month follow-up period. The root mean square (RMS), the median power frequency (MPF) of the surface electromyography (sEMG) signals, and the biting force (kgf) were recorded and normalized relative to the pretreatment condition. The data were analyzed by repeated-measure analysis of variance (ANOVA), with the significance level set at 5%. Results: Both the superficial masseter and the anterior temporal muscles presented an increase in sEMG signal activity during the treatment, with a marked increase in the latter compared to the former (p<0.05). Moreover, a significant decrease in bite force was evidenced (p<0.05). Conclusions: This preliminary study observed that the orthodontic aligners affected the muscle recruitment pattern of masticatory muscles, and reduced biting performance during the 8-month follow-up period.

RESUMO Introdução: O surgimento dos alinhadores ortodônticos tem proporcionado uma opção estética e confortável para o tratamento ortodôntico. No entanto, o design encapsulado dos alinhadores pode influenciar os músculos mastigatórios e comprometer a segurança do tratamento. Objetivo: Este estudo longitudinal preliminar teve como objetivo investigar se o uso de alinhadores ortodônticos afeta a força de mordida e a atividade mioelétrica dos músculos masseter superficial e temporal anterior. Métodos: Dez indivíduos participaram do estudo e foram submetidos a tratamento durante um período de acompanhamento de 8 meses. A raiz quadrada média (RMS), a frequência mediana de potência (FMP) dos sinais de superfície da eletromiografia (sEMG) e a força de mordida (kgf) foram registradas e normalizadas em relação à condição de pré-tratamento. Os dados foram analisados por análise de variância para medidas repetidas (ANOVA), com nível de significância estabelecido em 5%. Resultados: Tanto o masseter superficial quanto o temporal anterior apresentaram aumento da atividade do sinal sEMG durante o tratamento, com aumento acentuado desse último em comparação ao primeiro (p<0,05). Além disso, foi evidenciada uma diminuição significativa da força de mordida (p<0,05). Conclusões: Esse estudo preliminar observou que os alinhadores ortodônticos afetaram o padrão de recrutamento muscular dos músculos mastigatórios e reduziram o desempenho da mordida durante o período de acompanhamento de oito meses.

Mechanical Properties of Mini-Implants Used in Extra-Radicular Anchorage

ABSTRACT Objective: To evaluate the mechanical properties of mini-implants (MIs) manufactured from stainless steel and compare them with conventional titanium-aluminum-vanadium alloy MIs. Material and Methods: The following groups were formed: G1 (n=24), 8×1.5 mm steel MIs; G2 (n=24), 12×2.0 mm steel MIs; and G3 (n=24), 10×1.5 mm titanium MIs. The 72 MIs were inserted in the infra zygomatic crest region of the maxilla and retromolar trigone in the jaw of 10 pigs. Pull-out, insertion torque, fracture and percussion tests were performed in order to measure the tensile strength, primary stability and fracture strength of MIs. A digital torque gauge was used to measure insertion and fracture torque, a universal mechanical testing machine was used for pull-out testing and a periotest device was used to measure the micromovement of MIs. For morphological and MI component evaluation, scanning electron microscopy (SEM) was performed. D'Agostino & Pearson, Kruskal-Wallis, and Dunn post-hoc and normality tests were used. Results: G2 insertion and fracture torques were significantly higher than G1 and G3 insertion and fracture torques (p<0.05). The pull-out and percussion tests presented similar values among the groups. SEM revealed that the fracture point was predominantly on the fourth thread for steel MIs (G1 and G2) and on the seventh thread for titanium-aluminum-vanadium MIs (G3). Conclusion: The mechanical properties of stainless steel MIs are superior to those of titanium-aluminum-vanadium alloy MIs.

Skeletal and alveolar changes in conventional rapid palatal expansion (RPE) and miniscrew-assisted RPE (MARPE): a prospective randomized clinical trial using low-dose CBCT.

BACKGROUND: This prospective randomized clinical trial aimed to evaluate the immediate and short-term skeletal, dentoalveolar, and periodontal effects of rapid palatal expansion (RPE) and miniscrew-assisted RPE (MARPE) in adolescent and young adult patients. METHODS: This study followed a two-arm, parallel, randomized clinical trial design that recruited patients with transverse maxillary deficiency in a 1:1 allocation ratio. Forty patients (14 men and 26 women) requiring maxillary expansion were randomly allocated to the RPE (n = 20, age = 14.0 ± 4.5) or MARPE (n = 20, age = 14.1 ± 4.2) groups. The assignment was performed via computer-generated block randomization, with a block size of four. Upon identical (35 turns) amount of expansion, low-dose cone-beam computed tomography images were taken before treatment (T0), immediately after expansion (T1), and after a 3-month consolidation period (T2). The primary outcome of this study comprised the assessment of midpalatal suture separation. Secondary outcomes included, skeletal, dentoalveolar, and periodontal measurements, which were performed at each time point. RESULTS: The frequency of midpalatal suture separation was 90% (18/20) and 95% (19/20) for the RPE and MARPE groups, respectively. A greater increase in nasal width in the molar region (M-NW) and greater palatine foramen (GPF) was observed immediately after the expansion (T1-T0) and consolidation periods (T2-T0) in the MARPE group compared to the RPE group (P < 0.05). The MARPE and RPE groups showed similar dentoalveolar changes except for the maxillary width (PM-MW, M-MW). The MARPE group presented greater bilateral first premolar (PM-MW) and molar (M-MW) maxillary width in relation to the RPE group (P < 0.05). Through the expansion and consolidation periods (T2-T0), lesser buccal displacement of the anchor teeth was observed in the MARPE group (PM-BBPT, PM-PBPT, M-BBPT [mesial and distal roots], and M-PBPT)( P < 0.05). CONCLUSIONS: Midpalatal suture separation was observed in 90% and 95% of patients in the RPE and MARPE groups, respectively. Both RPE and MARPE groups exhibited significant triangular basal bone expansion and skeletal relapse during consolidation. Under identical amounts of expansion, the MARPE group showed lower decrease in the skeletal, dentoalveolar and periodontal variables after consolidation. The reinforcement of RPE with miniscrews contributes to the maintenance of the basal bone during consolidation period. Trial registration WHO Institutional Clinical Trials Registry Platform (IRB No. KCT0006871 / Registration date 27/12/2021).

A clinical approach to managing open-bite malocclusion associated with severe crowding.

Open bite has been identified as one of the most challenging malocclusions in orthodontics. The treatment approach is complex, the resulting esthetics may not meet the patient's expectations, and the chance of recurrence is high. A 13-year-old girl presented a skeletal Class II malocclusion associated with anterior and posterior open bite, maxillary transverse deficiency, severe anterior crowding, and a hyperdivergent facial pattern. Orthodontic treatment was performed with a Haas expander and subsequent standard edgewise appliances, and the 4 first premolars were extracted. The vertical control of facial growth was undertaken with vertical pull chincap therapy, mini-implants associated with a titanium-molybdenum alloy cantilever on the right and left buccal sides, and a stainless steel alloy transpalatal arch. Posttreatment records showed a bilateral Class I molar relationship, ideal overbite and overjet, and improved facial profile and gingival health. The cephalometric analysis revealed a good balance of the skeletal pattern and facial profile, with an appropriate inclination of the maxillary and mandibular incisors. After a 7-year retention period, the outcome was pleasant facial esthetics and smile and stability of the dental occlusion. This case shows that the clinical approach was adequate, with treatment outcomes achieving positive aspects of function, esthetics, and stability.

Characteristics of patients seeking orthodontic retreatment.

BACKGROUND: The aim of this cross-sectional study was to investigate patients' experiences with previous orthodontic treatment for those seeking retreatment, and their expectations and motivation for doing so. METHODS: A total of 72 patients were invited to answer an anonymous questionnaire. Of these, 36 (13 men and 23 women, mean age 26.3 ± 5.8 years) were seeking retreatment (study group), and 36 (13 men and 23 women, mean age 25.5 ± 6.8 years) were seeking treatment for the first time (control group). Casts from both groups were assessed with the index of complexity, outcome, and need (ICON) score, to objectively determine the treatment need and complexity. Student`s t test for independent samples, and paired Student`s t test, were performed for comparisons between the retreatment and control groups, and between retreatment and previous treatment, respectively. RESULTS: There was no statistically significant difference between retreatment patients` motivation for the previous treatment and motivation for the retreatment. However, the mean visual analog scale (VAS) scores for motivation differed significantly between the retreatment and control groups (73.8 ± 23.9 and 87.5 ± 14.5, respectively). The mean ICON score of the retreatment group was lower than that for the control group (25 ± 14 and 31 ± 16, respectively). CONCLUSIONS: Patients seeking retreatment were less motivated for treatment, and tooth irregularity was the chief reason for seeking treatment in both groups. Although an objective treatment need was not observed in the 2 groups, all of them had some occlusal traits that clinically justified the orthodontic treatment.

Escolha de attachment para alinhadores "in office" / Choosing attachment for "in office" aligners

Resumo A escolha de attachments é uma das estratégias disponíveis para aumentar a área de pressão do alinhador com o dente, criando maior retenção e gerando vetores de força adicionais na direção do movimento desejado no planejamento virtual com alinhadores "in office" (AIO). Devem ser considerados como importantes elementos auxiliares desta modalidade ortodôntica, gerando maior previsibilidade e segurança ao tratamento ortodôntico. Dessa forma, o objetivo desse artigo é fornecer informações sobre o uso dos attachments mais comumente utilizados para o planejamento virtual de AIO, de acordo com a movimentação dentária. O alinhador recobre toda a superfície dentária, com isso, este dispositivo apresenta uma capacidade única de aplicar forças compressivas em todas as direções. Porém observando sua desvantagem de tensão e deformação do material plástico, constata-se a necessidade de incluir attachments com pré-requisitos distintos e conceitos biomecânicos variados. Foram realizadas simulações ilustrativas no software Archform (San Jose, EUA), de acordo com os tipos de attachments e respectivas características para favorecer o movimento planejado. Pontos cruciais como o formato, tamanho, localização, orientação e anatomia dentária influenciam a eficiência do alinhador, e foram abordados para a respectiva conduta de escolha dos attachments frente aos movimentos variados. Desta forma, para maior assertividade por parte do ortodontista na movimentação dentária que se deseja aplicar, torna-se imprescindível conhecer os tipos de attachment e suas principais indicações clínicas. (AU)

Abstract Choosing attachments is one of the available strategies to increase the pressure area of the aligner with the tooth, creating greater retention and generating additional force vectors in the direction of the desired movement in the virtual planning with "in office" aligners (IOA). They should be considered as important auxiliary elements of this orthodontic modality, obtaining greater predictability and security for the orthodontic treatment. Thus, the aim of this article is to provide information on the use of the most commonly used attachment for virtual IOA planning, according to the desired tooth movement. The aligner covers the entire tooth surface and, with that, this device has a unique ability to apply compressive forces in all directions. However, observing its disadvantage of tension and deformation of the plastic material, it is verified the need to include an attachment with pre-adjustment different requirements and biomechanical concepts. Illustrative simulations were carried out in the Archform software (San Jose, USA), according to the types of attachmentes and their characteristics to favor the planned movement. Crucial points such as format, size, location, orientation, and dental anatomy influence the efficiency of the aligner, and were addressed for the respective conduct of choosing the attachmentes in varied movements. Thus, in order for the orthodontist to be more assertive with the desired tooth movement, it is essential to know the types of attachment and their main clinical indications. (AU)

Dentofacial and skeletal pattern in African descendants from southeastern Brazil: clinical prospective study.

OBJECTIVE: The aim of this study was to evaluate characteristics of African-Brazilians young adults with excellent dental occlusion, including bimaxillary protrusion; compare them to European-American Caucasian standards, and determine whether there is sexual dimorphism in the display of this phenotype. METHODS: Lateral cephalometric radiographs were obtained from 43 African-Brazilians within military personnel (28 males and 15 females, average age 22.4 ± 3.4 years) with normal occlusion, selected from a group of 394 volunteers. Thirty-one angular and linear measurements were evaluated. Student's t-test for independent samples was used to compare results with those established by European-American standards, previously described in the literature. RESULTS: Considering the dentoalveolar pattern, seven angular and six linear measurements showed statistically significant differences (p< 0.001) when compared to Caucasian cephalometric standards. African-Brazilians' subjects showed lower cranial base angle (SNAr = 119.87 ± 5.66º) and anterior cranial base length (SN-distance = 68.63 ± 4.50 mm) (p< 0.001). The maxilla (SNA = 88.51 ± 3.23º) and the mandible (SNB = 85.06 ± 3.24º) were protruded in relation to the SN line (p< 0.001). Sexual dimorphism was significant for L1.NB (degrees) (p< 0.01), and interincisal angle (U1.L1) (p< 0.05). CONCLUSION: African-Brazilian young adults presented differences regarding dental and craniofacial characteristics, when compared to European-American norms. It can be stated that Caucasian cephalometric norms should not be applied to African-Brazilian faces.

Reasons influencing the preferences of prospective patients and orthodontists for different orthodontic appliances.

OBJECTIVE: To evaluate the reasons influencing the preferences for a certain type of orthodontic appliance over another among prospective patients (PP) and orthodontists. METHODS: A total of 49 PP and 51 orthodontists were asked about their preferences for the following appliances: clear aligners (CA), lingual metallic brackets (LMB), polycrystalline and monocrystalline ceramic brackets, and buccal metallic brackets (BMB). The participants rated the importance of 17 potential reasons that would explain their choices. The reasons that contributed most to these preferences were identified. Non-parametric tests (Fisher's exact, χ2 and Mann-Whitney tests) and multivariate analyses (regression and discriminant analysis) were used to assess the data (α = 0.05). RESULTS: CA and BMB were the most chosen appliances by PP and orthodontists, respectively. LMB was the most rejected option among both groups of participants (p < 0.001). Rates of the importance of pain/discomfort, smile esthetics, finishing details, and feeding/speech impairment showed the highest differences between PP and orthodontists (p < 0.0005). Discriminant analyses showed that individuals who considered treatment time and smile esthetics as more important were more likely to prefer CA, while those who prioritized finishing details and cost were more likely to choose BMB (p < 0.05). CONCLUSIONS: Reasons related to comfort and quality of life during use were considered as more important by PP, while those related to the results and clinical performance of the appliances were considered as more relevant by orthodontists.

Dentofacial and skeletal pattern in African descendants from southeastern Brazil: clinical prospective study

ABSTRACT Objective: The aim of this study was to evaluate characteristics of African-Brazilians young adults with excellent dental occlusion, including bimaxillary protrusion; compare them to European-American Caucasian standards, and determine whether there is sexual dimorphism in the display of this phenotype. Methods: Lateral cephalometric radiographs were obtained from 43 African-Brazilians within military personnel (28 males and 15 females, average age 22.4 ± 3.4 years) with normal occlusion, selected from a group of 394 volunteers. Thirty-one angular and linear measurements were evaluated. Student's t-test for independent samples was used to compare results with those established by European-American standards, previously described in the literature. Results: Considering the dentoalveolar pattern, seven angular and six linear measurements showed statistically significant differences (p< 0.001) when compared to Caucasian cephalometric standards. African-Brazilians' subjects showed lower cranial base angle (SNAr = 119.87 ± 5.66º) and anterior cranial base length (SN-distance = 68.63 ± 4.50 mm) (p< 0.001). The maxilla (SNA = 88.51 ± 3.23º) and the mandible (SNB = 85.06 ± 3.24º) were protruded in relation to the SN line (p< 0.001). Sexual dimorphism was significant for L1.NB (degrees) (p< 0.01), and interincisal angle (U1.L1) (p< 0.05). Conclusion: African-Brazilian young adults presented differences regarding dental and craniofacial characteristics, when compared to European-American norms. It can be stated that Caucasian cephalometric norms should not be applied to African-Brazilian faces.

RESUMO Objetivo: O objetivo do presente estudo foi avaliar características de jovens adultos afro-brasileiros com oclusão excelente, incluindo protrusão bimaxilar, e compará-los com os padrões caucasianos europeu-americanos, para determinar se há dimorfismo sexual na exibição desse fenótipo. Métodos: Radiografias cefalométricas laterais foram obtidas de 43 afro-brasileiros militares (28 homens e 15 mulheres, idade média de 22,4 ± 3,4 anos) com oclusão normal, selecionados de um grupo de 394 voluntários. Foram avaliadas 31 medidas angulares e lineares. O teste t de Student para amostras independentes foi utilizado para comparar os resultados com os estabelecidos pelos padrões caucasianos europeu-americanos, descrito previamente na literatura. Resultados: Considerando o padrão dentoalveolar, sete medidas angulares e seis lineares apresentaram diferenças estatisticamente significativas (p< 0,001) quando comparadas aos padrões cefalométricos caucasianos. Sujeitos afro-brasileiros apresentaram menor ângulo da base do crânio (SNAr = 119,87 ± 5,66º) e comprimento da base craniana anterior (distância SN = 68,63 ± 4,50 mm) (p< 0,001). A maxila (SNA = 88,51 ± 3,23º) e a mandíbula (SNB = 85,06 ± 3,24º) estavam protruídas em relação à linha SN (p< 0,001). O dimorfismo de sexo foi significativo para L1.NB (graus) (p< 0,01) e ângulo interincisal (U1.L1) (p< 0,05). Conclusão: Jovens adultos afro-brasileiros apresentaram diferenças em relação às características dentárias e craniofaciais, quando comparados às normas europeias-americanas. Pode-se afirmar que as normas cefalométricas caucasianas não devem ser aplicadas às faces de indivíduos afro-brasileiros.

Cephalometric profile norms for southeastern african-brazilian adults according to the Legan-Burstone analysis: a pilot study

The aim of this pilot study was to determine cephalometric profile norms for a sample of African-Brazilian young adults with excellent occlusion and compare them to Caucasian standards. Methods: Lateral cephalograms of 43 individuals of both genders (28 male and 15 female), with average age of 22.40 ± 3.40 years, were used to evaluate 13 variables proposed by the Legan-Burstone analysis. Student´s independent t-test was used to compare resulting values with those set by European-American standards. Results: Significant differences were found (p < 0.001) between African-Brazilians and Caucasians as for: maxillary and mandibular prognathism, vertical height ratio, lower face-throat angle, lower vertical height-depth ratio, nasolabial angle, upper and lower lip protrusion, mentolabial sulcus and vertical lip-chin ratio. Facial convexity angle, maxillary incisor exposure and interlabial gap did not present statistical differences when ethnic groups were compared. Males displayed increased lower face-throat angles and vertical lip-chin ratios (p <0.05) while females presented increased maxillary incisor exposures (p <0.05). Conclusion: Caucasian cephalometric norms do not apply to African-Brazilian young adults. Therefore, morphological differences in the faces of such individuals should be taken into account during diagnosis and orthodontic treatment planning stages.

Objetivo: O objetivo deste estudo piloto foi determinar as normas do perfil cefalométrico para uma amostra de jovens adultos afro-brasileiros com oclusão excelente e, compará-las com os padrões caucasianos. Métodos: Cefalogramas laterais de 43 indivíduos de ambos os sexos (28 homens e 15 mulheres), com idade média de 22,40 ± 3,40 anos, foram utilizados para avaliar 13 variáveis propostas pela análise de Legan-Burstone. O teste t independente de Student foi utilizado para comparar os valores resultantes com os estabelecidos pelos padrões euroamericanos. Resultados: Foram encontradas diferenças significativas (p <0,001) entre afro-brasileiros e caucasianos quanto a: prognatismo maxilar e mandibular, razão vertical da altura, menor ângulo face-pescoço, menor razão vertical altura profundidade, ângulo nasolabial, protrusão labial superior e inferior, sulco mentolabial e razão vertical lábio-mento. O ângulo de convexidade facial, a exposição dos incisivos superiores e o gap interlabial não apresentaram diferenças estatísticas quando comparados os grupos étnicos. Os homens apresentaram maiores ângulos face-pescoço e razões verticais lábio-queixo (p<0,05), enquanto as mulheres apresentaram maior exposição dos incisivos superiores (p <0,05). Conclusão: As normas cefalométricas caucasianas não se aplicam a jovens adultos afro-brasileiros. Portanto, diferenças morfológicas nas faces desses indivíduos devem ser levadas em consideração durante as etapas de diagnóstico e planejamento do tratamento ortodôntico.

Mandibular buccal shelf and infrazygomatic crest thicknesses in patients with different vertical facial heights.

INTRODUCTION: The purpose of this study was to use cone-beam computed tomography (CBCT) to determine bone thickness in the mandibular buccal shelf (MBS) and the infrazygomatic crest (IC) in individuals with different vertical facial heights for ultimate placement of miniscrews. METHODS: The sample consisted of 100 individuals aged at least 16 years, of whom 58 were women, and 42 were men. The mean age was 19.18 years (± 5.5 standard deviation). The patients' facial height was determined by the gonial angle. Cross-sectional slices of the MBS and IC were obtained with CBCT to evaluate bone thickness for the insertion of miniscrews in these extra-alveolar sites. Spearman's nonparametric test was used to correlate the gonial angle with MBS and IC thickness. The level of significance was 5%. RESULTS: The gonial angle ranged from 102.4° to 143.2°. Bone thickness in the MBS increased posteriorly, whereas bone thickness in the IC decreased posteriorly. There was an inversely proportional correlation between the gonial angle and the MBS. There was no correlation between the IC and the gonial angle. CONCLUSIONS: Short-faced individuals had higher bone thickness values in the MBS than long-faced ones. There was no correlation between the patients' vertical face height and the bone width in the IC. The best site to install miniscrews in the MBS is buccal to the second molar distal root, whereas in the IC, it is buccal to the first molar mesiobuccal root. CBCT may be necessary to install extra-alveolar miniscrews correctly, especially in the IC.

The influence of cigarette smoke on colour stability and friction property of aesthetic orthodontic wires-In vitro study.

OBJECTIVE: To evaluate the colour stability and friction property of aesthetic orthodontic wires when exposed to cigarette smoke. MATERIALS AND METHODS: Forty-eight samples of aesthetic orthodontic wires (0.019″×0.025″) were allocated to three experimental groups according to their brand (n=8): GAD (Aditek™); GTP (TP Orthodontics™); GRM (Rocky Mountain™) and their respective control groups (GC) (n=8). Samples were exposed to 2 cycles of smoke in a hermetic chamber while GCs were stored in artificial saliva at 37°C. Colour analysis (CIEL*a*b* colour space and NBS units) was performed on 5mm wire segments with the Vita Easyshade Compact spectrophotometer. The friction analysis was performed in a universal test machine, in segments of 5cm wires tied to ceramic brackets with maximum values recorded in N/cm. The comparison between groups was performed with the ANOVA/Tukey test (a=0.05) and the effect of the time evaluated with ANOVA-MR with Bonferroni correction (a=0.016). RESULTS: GTP and GRM did not show significant colour and friction property variations and did not differ from GC during the study (P>0.05). However, GAD was significantly sensitive to colour changes (T1-T0-L*: -4.09±1.06; a*: 2.25±0.39; b*: 1.70±0, (T2-T0-L* 0.66±0.92; a*: 2.76±0.35) and friction (T2-T0: 2.07±1.00N/cm) (P<0.016). CONCLUSION: Exposure to cigarette smoke may alter the mechanical and optical properties of aesthetic orthodontic wires.

Influence of orthodontic loading on biomarkers levels around miniscrews.

OBJECTIVE: The aim of this study was to evaluate the levels of Interleukin-1α (IL-1α), Interleukin-1ß (IL-1ß), Interleukin-1 receptor antagonist (IL-1Ra), Interleukin-10 (IL-10), Interleukin-13 (IL-13), Vascular endothelial growth factor (VEGF), Granulocyte-colony stimulating factor (G-CSF), and Growth related oncogene (GRO) in the peri-miniscrew implant crevicular fluid (MICF) under orthodontic loading. DESIGN: The study sample comprised 14 miniscrews immediately loaded and 17 unloaded ones. A load of 200gF was immediately applied to the miniscrews in the loaded group after the placement surgery. Peri-miniscrew implant crevicular fluid was collected at baseline, at day 7, and at day 21. The levels of the biomarkers were measured using a multiplexed bead immunoassay. Intergroup comparisons were made using Mann-Whitney test. Friedman and Dunn's multiple comparison tests were used to evaluate intragroup differences over time. RESULTS: Although no statistical differences were observed between the groups at any time point for any of the 8 biomarkers evaluated, there was a statistically significant increase (p < 0.02) in the levels of all the biomarkers over time on both groups. CONCLUSIONS: An immediate loading of 200gF does not alter the balance in the inflammatory response in peri-miniscrew tissues.

Macroscopic and microscopic evaluation of flapless alveolar perforations on experimental tooth movement

Abstract Objective: The aim of this study was to evaluate a flapless surgical technique as an alternative to traditional alveolar corticotomy used to accelerate orthodontic tooth movement (OTM). Methods: To induce OTM in Wistar rats, 40 cN of orthodontic force were applied to the maxillary left first molars. Forty rats were distributed into control groups (CG1, CG3, CG7 and CG14) and experimental groups (n= 5), in which alveolar perforations were made using a spear-shaped guide bur (EG1, EG3, EG7, EG14). Euthanasia dates were set at 1, 3, 7 and 14 days, respectively, after tooth movement began. The amount of OTM was measured with a caliper, and osteoclasts present in the periodontal ligament of the mesial root of the moved tooth were counted by means of histological evaluation (tartrate-resistant acid phosphatase staining, TRAP). Results: Although there was no difference in the amount of OTM within subgroups of corresponding experimental periods (p> 0.05), when EG14 and CG14 were compared, a larger number of osteoclasts was counted in the experimental group (p< 0.00). Conclusion: The authors concluded that flapless cortical alveolar perforations led to more intense osteoclastic activity on the fourteenth day; nevertheless, no evidence of accelerated OTM could be noted.

Resumo Objetivo: o objetivo do presente estudo foi avaliar a técnica cirúrgica sem retalho como alternativa à tradicional corticotomia alveolar utilizada para acelerar o movimento dentário experimental. Métodos: para induzir a movimentação dentária experimental em ratos Wistar, foram aplicados 40 cN de força ortodôntica aos primeiros molares superiores esquerdos. Quarenta ratos foram distribuídos nos grupos (n = 5) controles (GC1, GC3, GC7 e GC14) e experimentais (GE1, GE3, GE7, GE14), nos quais foram realizadas perfurações alveolares com uma ponta lança. As datas de eutanásia foram estabelecidas em 1, 3, 7 e 14 dias, respectivamente, após o início do movimento dentário. A quantidade de deslocamento dentário foi medida com um paquímetro e os osteoclastos presentes no ligamento periodontal da raiz mesial do dente movimentado foram contados por meio de avaliação histológica (coloração por fosfatase ácida resistente ao tartarato, TRAP). Resultados: embora não tenha havido diferença na quantidade de deslocamento dentário dentro dos subgrupos dos períodos experimentais correspondentes (p> 0,05), quando GC14 e GE14 foram comparados, um número maior de osteoclastos foi contado no grupo experimental (p< 0,00). Conclusão: os autores concluíram que as perfurações alveolares corticais sem retalho levaram a uma atividade osteoclástica mais intensa no décimo quarto dia; entretanto, nenhuma evidência de movimento dentário acelerado pôde ser notada.

Mini-implant selection protocol applied to MARPE.

INTRODUCTION: Rapid maxillary expansion (RME) is the therapy of choice to correct skeletal transverse dimension in children and adolescents, associating orthopedic and dental effects. In an attempt to prevent the undesirable dentoalveolar effects and optimize the potential of skeletal expansion in individuals in advanced stages of skeletal maturation, the miniscrew-assisted rapid palatal expander (MARPE) was proposed by Lee et al. in 2010. OBJECTIVE: This paper presents a systematized protocol for selection of miniscrews indicated for MARPE, by the evaluation of cone-beam computed tomographies (CBCT). Variables related with the bone and soft tissue thicknesses at the palatal regions of interest, as well as in relation to the fixation rings of miniscrews of the palatal expander are analyzed and discussed to provide better performance in the clinical practice.

Mini-implant selection protocol applied to MARPE

Abstract Introduction: Rapid maxillary expansion (RME) is the therapy of choice to correct skeletal transverse dimension in children and adolescents, associating orthopedic and dental effects. In an attempt to prevent the undesirable dentoalveolar effects and optimize the potential of skeletal expansion in individuals in advanced stages of skeletal maturation, the miniscrew-assisted rapid palatal expander (MARPE) was proposed by Lee et al. in 2010. Objective: This paper presents a systematized protocol for selection of miniscrews indicated for MARPE, by the evaluation of cone-beam computed tomographies (CBCT). Variables related with the bone and soft tissue thicknesses at the palatal regions of interest, as well as in relation to the fixation rings of miniscrews of the palatal expander are analyzed and discussed to provide better performance in the clinical practice.

Resumo Introdução: a expansão rápida da maxila (ERM) é a terapia de escolha para a correção da dimensão transversa esquelética em crianças e adolescentes, associando-se efeitos ortopédicos e dentários. Com a finalidade de prevenir os efeitos dentoalveolares indesejáveis e otimizar o potencial de expansão esquelética em indivíduos com estágios avançados de maturação esquelética, a técnica de expansão rápida da maxila assistida por mini-implantes (MARPE) foi proposta por Lee e colaboradores em 2010. Objetivo: o presente estudo apresenta um protocolo sistematizado para seleção de mini-implantes indicados para a MARPE, mediante avaliação de imagens de tomografia computadorizada de feixe cônico (TCFC). Variáveis relacionadas à espessura de tecido ósseo e tecido mole nas regiões de interesse do palato, bem como em relação ao anel de fixação dos mini-implantes do parafuso expansor, são analisadas e discutidas para proporcionar melhor desempenho na prática clínica.