Shear bond strength of new and recycled brackets to enamel.

The purpose of this study was to evaluate in vitro the shear bond strength of recycled orthodontic brackets. S2C-03Z brackets (Dental Morelli, Brazil) were bonded to the buccal surfaces of 50 extracted human premolars using Concise Orthodontic chemically cured composite resin (3M, USA). The teeth were randomly assigned to 5 groups (n=10), as follows. In group I (control), the bonded brackets remained attached until shear testing (i.e., no debonding/rebonding). In groups II, III and IV, the bonded brackets were detached and rebonded after recycling by 90-microm particle aluminum oxide blasting, silicon carbide stone grinding or an industrial process at a specialized contractor company (Abzil-Lancer, Brazil), respectively. In group V, the bonded brackets were removed and new brackets were bonded to the enamel surface. Shear bond strength was tested in an Instron machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant difference (p>0.05) between the control brackets (0.52 kgf/mm2), brackets recycled by aluminum oxide blasting (0.34 kgf/mm2) and new brackets attached to previously bonded teeth (0.43 kgf/mm2). Brackets recycled by the specialized company (0.28 kgf/mm2) and those recycled by silicon carbide stone grinding (0.14 kgf/mm2) showed the lowest shear strength means and differed statistically from control brackets (0.52 kgf/mm2) (p<0.05). In conclusion, the outcomes of this study showed that bracket recycling using 90-microm aluminum oxide particle air-abrasion was efficient and technically simple, and might provide cost reduction for orthodontists and patients alike.

Comparative cephalometric study between nasal and predominantly mouth breathers.

AIM: To evaluate the possible correlation between the respiratory pattern in determining the craniofacial dimensions, using as baseline the Tweed-Merrifields cephalometric analysis, added to angle SN-GoGn and to Y axis angle. METHODOLOGY: The selected sample to this study comprised 50 teleradiographies taken in lateral and natural positions of the head in young female patients at the age of 9 to 12 years, presenting mean age of 10 years and 5 months and Class 1 malocclusion. After diagnosis of respiratory pattern, the sample was divided into two groups: control group, 25 teleradiographies of nasal breathers in lateral and natural positions of the head; experimental group, 25 teleradiographies of predominantly mouth breathers in lateral and natural positions of the head. RESULTS: The results were submitted to descriptive analysis (mean and standard deviation), test F and "t" Student test with significance level of 5%. There was no significant difference between the group with nasal breathing and the group with predominantly mouth breathing for any of the studied variables.

Expectations of orthodontic treatment in adults: the conduct in orthodontist/patient relationship.

INTRODUCTION: The high demand for orthodontic treatment, evidenced over the last few decades, has been justified mainly by the greater importance given to facial esthetics, influencing individual's self esteem. However, the professional frequently does not meet all the patient's expectations, for not establishing good communication and not knowing about the critical points during orthodontic treatment. OBJECTIVE: The aim of this study was to elucidate patients' desires and doubts regarding orthodontic treatment, by means of a survey applied to 60 adult patients. RESULTS: The analysis of results revealed that most individuals (38.3%) noticed treatment success after its conclusion. Occlusion deviation was pointed out by 66.7% as the main reason for seeking treatment, and esthetics ranked as second (with 48.3%). Treatment time was considered within the prediction by 46.7% of the interviewees and the results were judged as very good by 43.3%. The social relations of most participants were not affected by treatment (73.3%). Also, 58.3% of the interviewees reported pain as the main complaint and 53.3% found it difficult to use dental floss. Most participants saw the orthodontist as a professional who was concerned about their health (76.7%), and believed that he/she was more able to treat them (96.6%) when compared with the general practitioner. CONCLUSIONS: The orthodontist/patient relationship enables an understanding of the expectations regarding orthodontic treatment, resulting in greater motivation and cooperation, leading to a successful outcome.

Clinical evaluation of the failure rates of metallic brackets.

OBJECTIVES: The aim of this study was to evaluate in vivo the bonding of metallic orthodontic brackets with different adhesive systems. MATERIAL AND METHODS: Twenty patients (10.5-15.1 years old) who had sought corrective orthodontic treatment at a University Orthodontic Clinic were evaluated. Brackets were bonded from the right second premolar to the left second premolar in the upper and lower arches using: Orthodontic Concise, conventional Transbond XT, Transbond XT without primer, and Transbond XT associated with Transbond Plus Self-etching Primer (TPSEP). The 4 adhesive systems were used in all patients using a split-mouth design; each adhesive system was used in one quadrant of each dental arch, so that each group of 5 patients received the same bonding sequence. Initial archwires were inserted 1 week after bracket bonding. The number of bracket failures for each adhesive system was quantified over a 6-month period. RESULTS: The number of debonded brackets was: 8--Orthodontic Concise, 2--conventional Transbond XT, 9--Transbond XT without primer, and 1--Transbond XT + TPSEP. By using the Kaplan-Meier methods, statistically significant differences were found between the materials (p=0.0198), and the Logrank test identified these differences. Conventional Transbond XT and Transbond XT + TPSEP adhesive systems were statistically superior to Orthodontic Concise and Transbond XT without primer (p<0.05). There was no statistically significant difference between the dental arches (upper and lower), between the dental arch sides (right and left), and among the quadrants. CONCLUSIONS: The largest number of bracket failures occurred with Orthodontic Concise and Transbond XT without primer systems and few bracket failures occurred with conventional Transbond XT and Transbond XT+TPSEP. More bracket failures were observed in the posterior region compared with the anterior region.

Comparação in vitro da resistência ao cisalhamento na interface "PAD" de resina/esmalte dentário / Shear strength in vitro comparison in the "PAD" interface of dental resin/enamel

Objetivo: o presente estudo comparou a resistência ao cisalhamento na interface ?pad? de resina/esmalte dentário em três materiais comumente utilizados para a colagem de bráquetes linguais. Materiais e método: foram elaborados 45 corpos de prova com incisivos bovinos inclusos em resina composta Transbond XT (3M Unitek, Monrovia, USA) para simulação dos ?pads?, os quais foram divididos em três grupos: Grupo I ? a colagem com a resina Sondhi Rapid Set (3M Unitek, Monrovia, USA); Grupo II - a colagem com o selante Maximum Cure (Reliance Orthodontics Products, Itasca, USA); Grupo III ? a colagem com a resina Natural Flow (Dfl, Ind e Com., Rio de Janeiro, Brasil). Após a colagem, os corpos de prova foram armazenados em água destilada em uma temperatura média de 37 °C por 24 horas. Em seguida, foram submetidos a ensaio de resistência ao cisalhamento em máquina universal de ensaios a uma velocidade de 0,5mm/minuto. Os dados foram submetidos à Análise de Variância, e as médias ao teste de Tukey (5%). Resultados: os valores médios de resistência ao cisalhamento foram 17,28 Mpa para o Grupo I, 18,63 Mpa para o Grupo II e 24,33 Mpa para o grupo III. Os resultados encontrados para o Grupo III foram estatisticamente superiores aos grupos I e II, que não apresentaram diferenças estatísticas entre si. Conclusões: a resina Natural Flow apresentou a maior resistência ao cisalhamento entre os três materiais testados, seguida pelo selante Maximum Cure e a resina Sondhi Rapid Set respectivamente; todos os materiais testados apresentaram resistência ao cisalhamento adequada para suprir as necessidades clínicas.

Expectations of orthodontic treatment in adults: the conduct in orthodontist/patient relationship

INTRODUCTION: The high demand for orthodontic treatment, evidenced over the last few decades, has been justified mainly by the greater importance given to facial esthetics, influencing individual's self esteem. However, the professional frequently does not meet all the patient's expectations, for not establishing good communication and not knowing about the critical points during orthodontic treatment. OBJECTIVE: The aim of this study was to elucidate patients' desires and doubts regarding orthodontic treatment, by means of a survey applied to 60 adult patients. RESULTS: The analysis of results revealed that most individuals (38.3 %) noticed treatment success after its conclusion. Occlusion deviation was pointed out by 66.7 % as the main reason for seeking treatment, and esthetics ranked as second (with 48.3 %). Treatment time was considered within the prediction by 46.7% of the interviewees and the results were judged as very good by 43.3 %. The social relations of most participants were not affected by treatment (73.3 %). Also, 58.3 % of the interviewees reported pain as the main complaint and 53.3 % found it difficult to use dental floss. Most participants saw the orthodontist as a professional who was concerned about their health (76.7 %), and believed that he/she was more able to treat them (96.6 %) when compared with the general practitioner. CONCLUSION: The orthodontist/ patient relationship enables an understanding of the expectations regarding orthodontic treatment, resulting in greater motivation and cooperation, leading to a successful outcome.

INTRODUÇÃO: a elevada procura por tratamentos ortodônticos, evidenciada nas últimas décadas, justifica-se principalmente pela maior importância à estética facial, influenciando a autoestima do indivíduo. Entretanto, muitas vezes o profissional não atinge todas as expectativas esperadas pelo paciente, por não estabelecer uma correta comunicação e conhecer os pontos críticos durante o tratamento ortodôntico. OBJETIVO: esse estudo objetivou elucidar os anseios e dúvidas de pacientes em relação ao tratamento ortodôntico por meio da aplicação de questionário a 60 pacientes adultos. RESULTADOS: a análise dos resultados revelou que a maioria dos indivíduos (38,3%) percebeu êxito após a finalização da terapêutica. O desvio da oclusão foi apontado por 66,7% como principal motivo de procura pelo tratamento, e, em segundo lugar, 48,3% pela estética. O tempo de tratamento foi considerado dentro do previsto por 46,7% dos entrevistados e os resultados foram julgados como muito bons para 43,3%. As relações sociais da maioria dos participantes não foram afetadas pelo tratamento (73,3%), sendo que 58,3% dos entrevistados relataram a dor como queixa principal, e 53,3% encontraram dificuldades no uso do fio dental. A maioria dos participantes vê o ortodontista como um profissional preocupado com sua saúde (76,7%), e acredita que é mais apto em relação ao clínico-geral para tratá-los (96,6%). CONCLUSÃO: o vínculo entre profissional e paciente possibilita compreender as expectativas em relação ao tratamento ortodôntico, resultando em maior motivação, cooperação e sucesso do tratamento.

Jarabak 's cephalometric analysis of Brazilian black patients.

The treatment of skeletal disharmonies presents better results when performed during the growth period. The physical changes that occur in every individual express growth, which is ruled by genetic, general and environmental factors. In order to identify such disharmonies and hence concentrate the clinical actions during treatment and influence facial growth, cephalometrics appears as a useful a diagnostic tool for identifying facial growth patterns or growth direction. Jarabak's cephalometric analysis is used to assess facial growth pattern of subjects with normal occlusion or malocclusions. The purpose of this study was to obtain mean values for cephalometric measurements from Jarabak's cephalometric analyses of black Brazilian subjects resident in the city of Piracicaba, São Paulo state, Brazil and vicinities, who presented Class I molar relationship with normal overjet and overbite, mild or no tooth crowding or spacing, and no history of orthodontic treatment. A sample of 37 stone plaster casts and 37 lateral teleradiographs from both male and female individuals aged 10 to 14 years was evaluated. Data were analyzed statistically by Student's t-test at 5% significance level. There was no significant differences between genders. The cephalometric measurements obtained in this study were similar to the Jarabak's standards, except for S-N mean value in females (66.50 mm +/- 3.16), which was significantly lower than the standard.

Clinical evaluation of the failure rates of metallic brackets

OBJECTIVES: The aim of this study was to evaluate in vivo the bonding of metallic orthodontic brackets with different adhesive systems. MATERIAL AND METHODS: Twenty patients (10.5-15.1 years old) who had sought corrective orthodontic treatment at a University Orthodontic Clinic were evaluated. Brackets were bonded from the right second premolar to the left second premolar in the upper and lower arches using: Orthodontic Concise, conventional Transbond XT, Transbond XT without primer, and Transbond XT associated with Transbond Plus Self-etching Primer (TPSEP). The 4 adhesive systems were used in all patients using a split-mouth design; each adhesive system was used in one quadrant of each dental arch, so that each group of 5 patients received the same bonding sequence. Initial archwires were inserted 1 week after bracket bonding. The number of bracket failures for each adhesive system was quantified over a 6-month period. RESULTS: The number of debonded brackets was: 8- Orthodontic Concise, 2- conventional Transbond XT, 9- Transbond XT without primer, and 1- Transbond XT + TPSEP. By using the Kaplan-Meier methods, statistically significant differences were found between the materials (p=0.0198), and the Logrank test identified these differences. Conventional Transbond XT and Transbond XT + TPSEP adhesive systems were statistically superior to Orthodontic Concise and Transbond XT without primer (p<0.05). There was no statistically significant difference between the dental arches (upper and lower), between the dental arch sides (right and left), and among the quadrants. CONCLUSIONS: The largest number of bracket failures occurred with Orthodontic Concise and Transbond XT without primer systems and few bracket failures occurred with conventional Transbond XT and Transbond XT+TPSEP. More bracket failures were observed in the posterior region compared with the anterior region.

Abordagem ortodôntica na correção da classe III com mordida aberta anterior com osteotomia sagital mandibular e mentoplastia – caso clínico / Orthodontic approach in class III correction associated to open bite with sagittal mandibular osteotomy and mentoplasty – case report

O presente trabalho tem a finalidade de relatar um caso orto-cirúrgico de uma paciente com má oclusão do tipo Classe III associada a uma mordida aberta anterior. O plano de tratamento foi estabelecido em quatro fases, a pré-cirúrgica, a transcirúrgica, a pós-cirúrgica e a fase de contenção. Após o diagnóstico, todas as metas do tratamento foram estabelecidas e discutidas de maneira conjunta entre o ortodontista e o cirurgião bucomaxilofacial. Na fase pré-cirúrgica foram feitos todos os procedimentos para a descompensação dentária em ambos os maxilares. O procedimento cirúrgico consistiu na rotação anti-horária da mandíbula por meio da osteotomia sagital do ramo mandibular juntamente com mentoplastia. Na fase transoperatória foi conseguida a intercuspidação dentária com obtenção de um trespasse vertical e horizontal adequados pelo ato cirúrgico e por procedimentos fisioterápicos até que fosse retomada a função ideal do sistema estomatognático. Após esta fase, a paciente retornou à clínica ortodôntica para que fosse submetida aos procedimentos de finalização. Foi colocada uma contenção superior e inferior.

The present study aims to report an ortho-surgical case of a patient with Class III malocclusion associated with an anterior open bite. The treatment plan was established in four phases, the pre-surgical, trans-surgical, post-surgical and the retention phase. After the diagnosis, all treatment goals were established and discussed jointly between the orthodontist and maxillofacial surgeon. At pre-surgical phase all procedures for dental decompensation were performed in both jaws. The surgical procedure consisted on a counterclockwise rotation of the mandible by sagittal osteotomy of the mandibular ramus with mentoplasty. At transoperative dental intercuspation was achieved through vertical and horizontal overlap suitable for surgery and physiotherapy procedures until this resume optimal function of the stomatognathic system. After this phase, the patient returned to the clinic to complete the procedure. An upper and lower retainer was placed.

Resistência ao cisalhamento da colagem com compósitos utilizando potencializador de adesão / Shear bond strength of composites using an adhesion booster

OBJETIVO: avaliar a resistência ao cisalhamento dos compósitos Transbond XT e Concise Ortodôntico utilizando o potencializador de adesão Ortho Primer. MÉTODOS: a amostra consistiu de 90 incisivos bovinos divididos em seis grupos (n=15). Todos os dentes receberam profilaxia com pedra-pomes e condicionamento do esmalte com ácido fosfórico. No Grupo I, utilizou-se Transbond XT de maneira convencional. O Grupo II foi semelhante ao I, porém, aplicou-se o Ortho Primer ao invés do XT Primer. No Grupo III, após condicionamento, o esmalte foi contaminado com saliva, aplicou-se o Ortho Primer e colagem com Transbond XT. No Grupo IV, utilizou-se o Concise Ortodôntico de maneira convencional. O Grupo V foi semelhante ao IV, porém, utilizou-se o Ortho Primer ao invés da resina fluida. No Grupo VI, após condicionamento, o esmalte foi contaminado com saliva, aplicou-se o Ortho Primer e colagem com Concise. Os corpos de prova foram armazenados em água destilada em estufa a 37ºC por 24h e submetidos ao ensaio de resistência ao cisalhamento. Os dados foram submetidos à ANOVA e ao teste de Tukey (5 por cento). RESULTADOS: a resistência da colagem no Grupo IV foi estatisticamente superior à dos Grupos II, III e VI (p<0,05). Entre os Grupos I, IV e V; e entre os Grupos I, II, III e VI não foram encontradas diferenças estatísticas significativas (p>0,05). O Transbond XT e o Concise utilizados convencionalmente obtiveram os maiores valores adesivos. O Ortho Primer em esmalte seco atuou efetivamente como agente de união dos compósitos avaliados. Em esmalte contaminado, a colagem com Concise obteve baixa resistência adesiva.

OBJECTIVE: To evaluate the shear strength of two composites (Transbond XT and Concise) using an adhesion booster (Ortho Primer).METHODS: The sample consisted of 90 bovine incisors divided into six groups (n=15). All teeth were subjected to prophylaxis with pumice and enamel etching with phosphoric acid. Transbond XT was used conventionally in Group I. Group II was handled similarly to Group I, except that Ortho Primer was applied instead of XT Primer. After etching, the enamel in Group III was contaminated with saliva, Ortho Primer was then applied and bonding performed using Transbond XT. In Group IV, Concise was used conventionally. Group V was handled similarly to Group IV, except that Ortho Primer was applied instead of the fluid resin. After etching, the enamel in Group VI was contaminated with saliva, Ortho Primer was then applied and bonding performed using Concise. The specimens were stored in distilled water at 37 ºC for 24 hours and subjected to shear strength testing. Data were analyzed with ANOVA and Tukey's test (5%).RESULTS: Bond strength in Group IV was statistically higher than in Groups II, III and VI (p<0.05). No statistically significant differences were found among Groups I, IV and V, and between I, II, III and VI (p>0.05). When used conventionally, both Transbond XT and Concise yielded the highest bond strength values. When applied to dry enamel, Ortho Primer acted effectively as a bonding agent for the composites under evaluation. When applied to contaminated enamel, Concise yielded low bond strength.

Tratamento da mordida aberta anterior com a utilização do gancho J / Treatment of open bite using J hook

O presente artigo tem a finalidade de relatar um caso clínico de uma paciente afro-brasileira, dolicofacial, 18 anos de idade, com mordida aberta anterior (MAA) dentoalveolar associada ao hábito de sucção digital. O tratamento ortodôntico consistiu na colocação de um aparelho ortodôntico fixo com bráquetes Edgewise e controle vertical com o uso do Gancho J com puxada alta somente na arcada inferior, com a finalidade de rotação anti-horária da mandíbula e o consequente fechamento da mordida. Simultaneamente, a paciente foi encaminhada para tratamento fonoaudiológico. O tratamento foi finalizado com êxito ao final de 36 meses com a correção da MAA havendo melhora das relações vertical e sagital entre a maxila e a mandíbula, obtenção de estética, equilíbrio e harmonia facial, além das características oclusais e funcionais. Assim, foi possível concluir que após a remoção do hábito de sucção digital é necessário que seja feita uma intervenção multidisciplinar que, neste caso, consistiu numa intervenção ortodôntica associada a um acompanhamento fonoaudiológico. Além disto, o uso de um extrabucal, colocado diretamente no aparelho ortodôntico na arcada inferior (Gancho J) foi primordial no fechamento da mordida, pois houve um controle vertical, o que proporcionou uma rotação mandibular no sentido anti-horário e o consequente fechamento da mordida.

This article aims to report a case of an Afro-Brazilian patient, dolicofacial, 18 years of age, with open bite dentoalveolar associated with digit sucking habit. Orthodontic treatment consisted on a fixed orthodontic appliance with edgewise brackets and vertical control using the J hook with high pull only in the lower jaw for the purpose of anti-clockwise rotation of the mandible and the consequent closing of the bite. Simultaneously, the patient was referred for speech therapy. The treatment was completed successfully at the end of 36 months with the correction of open bite with an improvement of vertical and sagittal relations between the maxilla and the mandible obtaining facial aesthetics and harmony besides the occlusal and functional characteristics. Thus, it was concluded that after breaking digit habit, a multidisciplinary intervention is required.In this case it consisted on an orthodontic intervention associated with a speech therapist. In addition, the use of a headgear placed directly on the archwire, the lower arch in the case was the J hook, was paramount in closing the bite because there was a vertical control which provided a mandibular rotation in a counterclockwise direction and the consequent closing of the bite

Analysis of the coefficient of variation in shear and tensile bond strength tests.

The coefficient of variation is a dispersion measurement that does not depend on the unit scales, thus allowing the comparison of experimental results involving different variables. Its calculation is crucial for the adhesive experiments performed in laboratories because both precision and reliability can be verified. The aim of this study was to evaluate and to suggest a classification of the coefficient variation (CV) for in vitro experiments on shear and tensile strengths. The experiments were performed in laboratory by fifty international and national studies on adhesion materials. Statistical data allowing the estimation of the coefficient of variation was gathered from each scientific article since none of them had such a measurement previously calculated. Excel worksheet was used for organizing the data while the sample normality was tested by using Shapiro Wilk tests (alpha = 0.05) and the Statistical Analysis System software (SAS). A mean value of 6.11 (SD = 1.83) for the coefficient of variation was found by the data analysis and the data had a normal distribution (p>0.05). A range classification was proposed for the coefficient of variation from such data, that is, it should be considered low for a value lesser than 2.44; intermediate for a value between 2.44 and 7.94, high for a value between 7.94 and 9.78, and finally, very high for a value greater than 9.78. Such classification can be used as a guide for experiments on adhesion materials, thus making the planning easier as well as revealing precision and validity concerning the data.

Alterações nas dimensões dos arcos dentários em pacientes com classe II, primeira divisão, tratados com AEB / Changes in dental arch dimensions in patients with class II, division 1, malocclusion treated with headgear

O objetivo deste estudo foi avaliar as possíveis alterações nas larguras intercaninos e intermolares, e no comprimento dos arcos dentários, em modelos de gesso, de pacientes submetidos ao tratamento ortodôntico com aparelho extrabucal (AEB). Para isso, foram selecionados 12 pares de modelos em gesso de pacientes com classe II, primeira divisão, antes e após o tratamento com AEB, totalizando 24 pares de modelos. As medidas da distância intermolares e intercaninos foram obtidas por meio de um paquímetro digital com precisão de 0,000 mm. Os resultados demonstraram aumento estatisticamente significante nas distâncias intermolares superiores. Não ocorreram diferenças estatisticamente significantes nas distâncias intercaninos e nos comprimentos dos arcos dentários. Concluiu-se que no tratamento ortodôntico com AEB em pacientes classe II, primeira divisão, na dentição mista, pode-se esperar um aumento significativo nas distâncias intermolares superiores...

The aim of this study was to evaluate possible changes in the intermolar distance, intercanine distance and arch length, through dental casts, of patients undergoing orthodontic treatment with headgear. To that end, we selected 12 pairs of dental casts of patients with class II, division 1 before and after treatment with headgear, totaling 24 pairs of dental casts. The measures of intermolar and intercanine distances were performed on casts with digital calipers accurate to 0.000 mm. The results showed a statistically significant increase in the upper intermolar distances. There were no statistically significant differences in the intercanine distances and dental arches lengths. It was concluded that orthodontic treatment with headgear in class II, division 1 patients, in mixed dentition we can expect a significant increase in the upper intermolar distances...

Craniofacial analysis of the Tweed Foundation in Angle Class II, division 1 malocclusion.

This study has defined the cephalometric values of the Craniofacial Analysis of the Tweed Foundation for a sample of Brazilian subjects. The sample consisted of 211 cephalometric radiographs from subjects aged 12-15, which were divided into two groups: Class II group, with 168 lateral teleradiographs (cephalograms) of white Brazilian subjects, with Angle Class II, division 1 malocclusion, of both genders (82 males and 86 females); and the Control Group, with 43 lateral teleradiographs (cephalograms) of subjects whose occlusion was clinically excellent, and also of both genders (21 males and 22 females). The teleradiographs were selected from the files of the Department of Orthodontics, School of Dentistry of Piracicaba, State University of Campinas, previously to the orthodontic treatment. The results demonstrated no sexual dimorphism for each group, as attested by the Student's t-test. The exploratory analysis (+/- 0.5 standard deviation) enabled the tolerance limits to be determined and a Craniofacial Analysis Table to be constructed using the respective cephalometric intervals. In addition, the difference between the two groups was not statistically significant according to the maxilla position. The maxilla was in a good position in relation to the cranial base. On the other hand, the mandible was retruded in relation to the cranial base in the Class II cases. The skeletal pattern was not defined because only the Facial Height Index (FHI) showed a vertical pattern in Class II subjects, while the Y Axis, SN.PlO, SN.GoMe and FMA values did not show any statistically significant difference between the groups. The Class II division 1 subjects showed lower incisors more labially tipped and a convex facial profile.

Aplicações do “gancho J” durante o tratamento ortodôntico / Use of “J-hook” during orthodontic treatment

O gancho “J” auxilia no redirecionamento das forças resultantes em sentido anti-horário, geradas durante o tratamento ortodôntico e pode ser aplicado diretamente sobre os dentes ou sobre ganchos soldados nos arcos metálicos, conforme a indicação ou a fase do tratamento ortodôntico. O objetivo do aparelho extrabucal gancho “J” é controlar rotações dos planos palatino, oclusal e mandibular que podem ocorrer durante o tratamento ortodôntico corretivo. O gancho “J” possui também aplicações clínicas específicas, tais como controle e correção do trespasse vertical, distalização de molares e caninos, retração em massa dos incisivos superiores e/ou inferiores, fechamento de mordida e/ou manutenção da posição dos incisivos mandibulares. Dentro deste contexto, o presente trabalho mostrará as possibilidades ortodônticas da utilização do gancho “J”, bem como as etapas para a sua elaboração.

The “J-hook” assists the redirection in anti-clockwise direction of resultant forces generated during orthodontic treatment, and can be applied directly on the teeth or hooks welded on the metal arches according to prescription or stage of the orthodontic treatment. The goal of the “J-hook” headgear is to control rotations of palatal occlusal and mandibular plans that may occur during orthodontic treatment. The “J-hook” also has specific clinical applications, such as control and correction of overbite, distalization of molars and canines, mass retraction of the upper/lower incisors, closing bite, maintenance of the position of mandibular incisors. Within this context, this work will present orthodontic possibilities of using “J-hook” and the steps for its preparation.

Assessment of the nasolabial angle in young Brazilian black subjects with normal occlusion.

Black individuals present craniofacial characteristics which differ from those of other races, especially the white race, whose cephalometric analyses are usually considered as the standard in routine orthodontic diagnosis and treatment planning. Further studies are therefore needed to enable more accurate and specific diagnoses for this ethnic group. The present study was conducted in order to assess average values for the nasolabial angle in young Brazilian black individuals with normal occlusion, and to assess the occurence of sexual dimorphism. Thirty-six lateral skull, extraoral radiographs from Brazilian black individuals were selected from the archives of the Scientific Recordings Department, Orthodontics Graduate Program, School of Dentistry of Piracicaba, State University of Campinas (UNICAMP). The patients' ages varied from 10 to 14 years, they presented normal occlusion upon clinical examination, and had not been submitted to orthodontic treatment. The cephalometric landmarks from which the nasolabial angle was obtained and measured were traced by a single researcher. Statistical analysis and evaluation of the results led to the conclusion that the nasolabial angle of young Brazilian black individuals is sharper, i.e., the soft tissue profile is more protruded. The average value for the whole sample was 88.14 degrees +/- 12.52 degrees. The nasolabial angle was statistically smaller among females (p < 0.05), demonstrating the occurrence of sexual dimorphism.

Shear bond strength of metallic brackets bonded with a new orthodontic composite

Aim: The aim of this study was to assess the shear bond strength of orthodontic brackets in different enamel surfaces using the Transbond Plus Color Change composite (TPCC-3M Unitek), and to analyze the Adhesive Remnant Index (ARI). Methods: Seventy-two human premolars were divided into six groups (n = 12), as follows: Group 1(control) - Transbond XT conventional; in Groups 2 to 6, TPCC was used under the following enamel treatment conditions: phosphoric acid and XT-primer; Transbond Plus Self-Etching Primer (TPSEP); phosphoric acid only; phosphoric acid, XT-primer and saliva; and TPSEP and saliva, respectively. Twenty-four hours after bonding, the brackets were debonded with an Instron machine at a crosshead speed of 0.5 mm/min, and ARI was evaluated by using a stereoscopic magnifying glass. Results: The mean shear strength values (MPa) for Groups 1 to 6 were 24.6, 18.7, 17.5, 19.7, 17.5 and 14.8, respectively. Data were submitted to ANOVA and Tukey's test (α = 0.05). Group 1 had significantly higher shear bond strength values than Groups 3, 5, and 6 (p < 0.05), but did not differ significantly from Groups 2 and 4 (p > 0.05). No statistically significant differences (p > 0.05) were found between Groups 2, 3, 4, 5 and 6. Conclusions: Bracket bonding using TPCC showed adequate adhesion for clinical use, and the type of enamel preparation had no influence.

Prevalence of malocclusion in a Brazilian schoolchildren population and its relationship with early tooth loss

The purpose of this study was to evaluate the prevalence of malocclusion in a Brazilian schoolchildren population in the mixed dentition, assessing its relationship with early tooth loss. The study population consisted of 1,014 7-11-year-old children of both genders, with low socioeconomic backgrounds and multiracial characteristics, living in the city of Jequié, in the Northeast region of Brazil. The clinical examination was carried out by an adequately calibrated orthodontist in the children’s classrooms. Data were analyzed statistically by either chi-square or Fisher’s exact test (a=0.05). Angle’s classification revealed that 22.3% of the population had normal occlusion. Class I malocclusion was observed in 47.6%, Class II division 1 in 21%, Class II division 2 in 0.9% and Class III in 8.2% of the children. Excluding the subjects (n=199) with early tooth loss, which is a condition that can modify malocclusion status, the distribution was as follows: Class I (36.2%), Class II division 1 (17.5%), Class II division 2 (0.7%) and Class III (3.7%). Early tooth loss was more commonly observed in boys (Class I, Class III left side, and both sides simultaneously). Anterior crossbite was observed in 5.7% of the subjects, posterior crossbite in 8.4%, anterior and posterior crossbite simultaneously in 2.6%, open bite in 13% and crowding in 49.6%. In conclusion, Class I malocclusion was the most prevalent alteration. The occlusal pattern of Class III was more common than Class II division 2, among the examined individuals.

The effect of repeated bracket recycling on the shear bond strength of different orthodontic adhesives

Aim: The aim of this study was to evaluate the effect of two consecutive recycling procedures on the shear bond strength of different orthodontic adhesives. Methods: Edgewise brackets were bonded to the buccal surfaces of 40 bovine incisors using the following bonding materials: Concise (group I), Transbond XT (group II), Smart Bond (group III) and Fuji Ortho (group IV). The teeth were stored in water at 37°C for 24 h, thermocycled between 5 and 55°C, and debonded using an Instron machine at a crosshead speed of 0.5 mm/min. In all groups, the bonded brackets were detached and rebonded after recycling by 50-µm particle aluminum oxide blasting. After the second recording of retentive strengths, the recycling procedure, the rebonding and the shear bond strength test were repeated. Data were analyzed statistically by ANOVA and Tukey’s test at 5% significance level. Results: The results showed that repeated recycling did not interfere in retention of brackets, regardless of the adhesive used. The highest shear bond strength values were obtained after bonding with Transbond XT, independent of the recycling procedure. Conclusion: Repeated bracket recycling using 50-µm aluminum oxide particle air abrasion did not affect the shear bond strength of metallic brackets bonded with different orthodontic adhesives.