Does mandibular advancement ortho-surgical procedure cause condyle changes? A case-series analysis

ABSTRACT Introduction: Mandibular advancement surgery corrects bone bases while establishing patients' functional and aesthetic rehabilitation. However, little is known about the results of this procedure in the structures that make up the stomatognathic system, as the condyles. Objective: This study aimed to evaluate the structural and positional changes of mandibular condyles in ortho-surgical patients who underwent mandibular advancement surgery. Material and Methods: A prospective investigation was conducted with cone-beam computed tomography images. Using Dolphin Imaging® software, seven ortho-surgical patients with Angle Class II malocclusion and mandibular deficiency were evaluated. The images assessed were obtained at pre-surgical phase and after, at least, 1 year of the procedure. To study the structural and positional changes of condyles, linear and angular measurements were obtained, and the right and left sides of patients were compared. Descriptive statistical analysis was performed and, in order to verify possible significant differences, normality tests (Kolmogorov-Smirnov) were applied, followed by a paired t-test to define significance. Results: For all measures evaluated in this study, no statistically significant differences were found. Conclusion: The ortho-surgical procedure performed did not change the structure and position of the condyles of patients who underwent surgical mandibular advancement. Right and left mandibular condyles behaved similarly, suggesting stability and condylar adaptation after surgery.

RESUMO Introdução: A cirurgia de avanço mandibular corrige as bases ósseas e estabelece a reabilitação funcional e estética dos pacientes. Entretanto, pouco se sabe sobre os resultados desse procedimento nas estruturas que compõem o sistema estomatognático, como os côndilos. Objetivo: Este estudo teve como objetivo avaliar as alterações estruturais e posicionais dos côndilos mandibulares em pacientes ortodôntico-cirúrgicos submetidos à cirurgia de avanço mandibular. Material e Métodos: Foi realizada investigação prospectiva com imagens de tomografia computadorizada de feixe cônico. Utilizando o software Dolphin Imaging®, foram avaliados sete pacientes ortodôntico-cirúrgicos com má oclusão Classe II de Angle e deficiência mandibular. Foram avaliadas imagens da fase pré-cirúrgica e de, no mínimo, um ano após o procedimento. Para estudar as alterações estruturais e posicionais dos côndilos, foram obtidas medidas lineares e angulares e comparados os lados direito e esquerdo dos pacientes. Foi realizada análise estatística descritiva e, para verificar possíveis diferenças significativas, foram aplicados testes de normalidade (Kolmogorov-Smirnov), seguido de teste t pareado, para definição de significância. Resultados: Para nenhuma das medidas avaliadas nesse estudo foram encontradas diferenças estatisticamente significativas. Conclusão: O procedimento ortodôntico-cirúrgico realizado não alterou a estrutura e a posição dos côndilos dos pacientes submetidos à cirurgia de avanço mandibular. Os côndilos mandibulares direito e esquerdo comportaram-se de forma semelhante, sugerindo estabilidade e adaptação condilar após a cirurgia.

Relação entre desmame precoce, desenvolvimento de hábitos bucais deletérios e maloclusões na infância / Relationship between early weaning, development of harmful oral habits and malocclusions in childhood

Objetivo: o objetivo desta pesquisa foi analisar a associação do tempo de aleitamento materno com a prática de hábitos deletérios e o desenvolvimento de maloclusões na primeira infância. Materiais e Métodos: foram aplicados 171 formulários às mães com 18 anos ou mais que acompanharam o processo de amamentação de seu(s) filho(s) de 4 a 10 anos de idade. O questionário foi composto por 22 perguntas, sendo 15 específicas e relacionadas ao aleitamento, hábitos deletérios da criança (uso de chupeta, sucção de dedo e sucção do próprio lábio) e maloclusões específicas (mordida cruzada posterior, mordida cruzada anterior e mordida aberta). Resultados: a prevalência da amamentação exclusiva por 6 meses ou mais foi de 52%, enquanto 29,8% das crianças foram amamentadas de 0 a 5 meses e 18,2% nunca foram amamentadas no seio exclusivamente. Quanto a alimentação complementar, grande parcela (37,4%) encontrada evidenciou início após os 6 meses; 57,9% das mães relataram algum tipo de dificuldade para amamentar e 34,5% das crianças fizeram uso de chupeta. Em relação aos hábitos deletérios, 10% desenvolveram sucção de dedo. O relato de desenvolvimento de maloclusões foi de 9,4% das crianças com mordida cruzada posterior; 7,6% mordida cruzada anterior e 18,7% mordida aberta anterior. Conclusão: sendo assim, é possível inferir que o tempo preconizado pela Organização Mundial da Saúde para aleitamento materno exclusivo foi fundamental para o não desenvolvimento de hábitos deletérios e maloclusões. Em contrapartida, quanto mais cedo a introdução de alimentos complementares, e a interrupção do aleitamento exclusivo nos seis primeiros meses, maior o risco do desenvolvimento de hábitos e consequentemente maloclusões.

Objective: the objective of this research was to analyze the association of breastfeeding duration with the practice of deleterious habits and the development of malocclusions in early childhood. Materials and Methods: a total of 171 forms were applied to mothers aged 18 years or older who followed the breastfeeding process of their child(ren) between 4 and 10 years of age. The questionnaire consisted of 22 questions, 15 of which were specific and related to breastfeeding, the child's deleterious habits (use of a pacifier, finger sucking and lip sucking) and specific malocclusions (posterior crossbite, anterior crossbite and open bite). Results: the prevalence of exclusive breastfeeding for 6 months or more was 52%, while 29.8% of children were breastfed from 0 to 5 months and 18.2% were never exclusively breastfed. As for complementary feeding, a large portion (37.4%) found to start after 6 months; 57.9% of the mothers reported some type of difficulty in breastfeeding and 34.5% of the children used a pacifier. Regarding deleterious habits, 10% developed finger sucking. The report of development of malocclusions was 9.4% of children with posterior crossbite; 7.6% anterior crossbite and 18.7% anterior open bite. Conclusion: therefore, it is possible to infer that the time recommended by the World Health Organization for exclusive breastfeeding was fundamental for the non-development of deleterious habits and malocclusions. On the other hand, the earlier the introduction of complementary foods and the interruption of exclusive breastfeeding in the first six months, the greater the risk of developing habits and, consequently, malocclusions.

Effect of cigarette smoke on aesthetic brackets: an in vitro study

ABSTRACT Objective: The objective of this study was to evaluate the effect of cigarette smoke (CS) on physical and mechanical properties of ceramic, polycarbonate and alumina ceramic brackets. The null hypothesis tested was that aesthetic brackets would not be influenced by CS. Methods: Ninety aesthetic brackets were allocated to three groups (n = 30): ceramic (GCE), polycarbonate (GCO) and alumina ceramic (GPS). Ten samples of each group were assigned to color and surface roughness analysis, performed before (T0) and after (T1) exposure to CS; and twenty samples were allocated into control and experimental groups (n = 10) (not exposed and exposed to CS, respectively) for shear bond strength test (SBS). Exposure to CS followed an adaptation of the method described by Le Mesurier. Colorimetric reading, surface morphology and roughness, SBS and adhesive remnant index (ARI) were assessed. Statistical analysis comprised independent and paired t-tests, ANOVA/Tukey and Fisher's exact tests (α = 0.05). Results: Changes were observed in brackets' color (NBS: GCE = 2.4; GCO = 1.9; GPS = 2.1), surface roughness (ΔRa: GCE = 1.1 ± 0.8 µm; GCO = 1.9 ± 1.5µm; GPS = -0.3 ± 0.1 µm / ΔRz: GCE = 1.4 ± 1.0 nm; GPS = -0.5 ± 0.1 nm); and SBS (GPS - experimental = 221.8 ± 48.6 N) after exposure to CS (p< 0.05). Conclusions: Exposure, in vitro, of aesthetic brackets to CS resulted in changes of color to darker and more opaque shades, surface roughness alterations, and higher SBS values. ARI scores were not associated with exposure to CS.

RESUMO Objetivo: O objetivo do presente estudo foi avaliar os efeitos da fumaça do cigarro (FC) nas propriedades físicas e mecânicas de braquetes cerâmicos, de policarbonato e de cerâmica de alumina. A hipótese nula testada foi de que os braquetes estéticos não seriam influenciados pela FC. Métodos: Noventa braquetes estéticos foram alocados em três grupos (n = 30): cerâmica (GCE), policarbonato (GCO) e cerâmica de alumina (GPS). Dez amostras de cada grupo foram designadas para análise de cor e rugosidade superficial, realizada antes (T0) e após (T1) exposição à FC, e vinte amostras foram alocadas nos grupos controle e experimental (n = 10) (não expostos e expostos à FC, respectivamente) para o teste de resistência ao cisalhamento (RC). A exposição à FC foi realizada de acordo com o método descrito por Le Mesurier. Leitura colorimétrica, morfologia e rugosidade de superfície, RC e índice de adesivo remanescente (ARI) foram avaliados. A análise estatística foi realizada por meio dos testes t independente e para amostras pareadas, ANOVA/Tukey e teste exato de Fisher (α = 0,05). Resultados: Foram observadas alterações na cor (NBS: GCE = 2,4; GCO = 1,9; GPS = 2,1), rugosidade superficial (ΔRa: GCE = 1,1 ± 0,8 µm; GCO = 1,9 ± 1,5 µm; GPS = -0,3 ± 0,1 µm / ΔRz: GCE = 1,4 ± 1,0 nm; GPS = -0,5 ± 0,1 nm) e RC (GPS - experimental = 221,8 ± 48,6 N) dos braquetes após exposição à FC (p< 0,05). Conclusões: A exposição in vitro de braquetes estéticos à FC resultou em mudanças na cor, para tons mais escuros e mais opacos; alterações na rugosidade superficial e maiores valores de RC. Os resultados do ARI não foram associados à exposição à FC.

Mapping of supernumerary elements in patients seeking orthodontic treatment

Dimension, number and shape alterations are frequently observed dental anomalies. Objective: The aim of this study was to map the frequency, the preferred location and the most prevalent types of supernumerary teeth, in the studied population. In addition, to assess the interference that supernumerary teeth may cause in the ectopic eruption of the normal dental series teeth. Methods: This is an observational retrospective study. Data collection was performed by evaluation of dental records of patients treated in an orthodontic clinic. Patients' radiographs, photographs and gypsum dental models were analyzed and data recorded in protocol files, by previously trained undergraduate and postgraduate students. Records from 1984 to 2019 were evaluated, and evaluation lasted two months. Data were stored in Microsoft Office Excel (version 2016) for descriptive analysis. Results: From the 920 patients' records analyzed, 2.7% presented at least one supernumerary tooth, with preferred location on the anterior maxillary area and mandibular parapremolar area. The most prevalent type was the supplemental tooth, with normal eruption orientation and normal alveolar location. Conclusion: The supernumerary teeth of the studied population showed little interference in the ectopic eruption of the normal dental series. Most of the supernumerary teeth were impacted, and, approximately one third of the supernumerary teeth showed deviated eruptions.

Introdução: Alterações de dimensão, número e forma são anomalias dentárias comumente observadas. Objetivo: O objetivo foi mapear a frequência de dentes supranumerários na população estudada, sua localização preferida e os tipos mais prevalentes. Além disso, avaliar a interferência que os dentes supranumerários podem causar na erupção ectópica da série dental normal. Métodos: A pesquisa possui desenho retrospectivo observacional. A coleta de dados foi realizada pela avaliação de prontuários odontológicos dos pacientes atendidos em uma clínica ortodôntica. Foram analisados radiografias, fotografias e modelos de gesso dental dos pacientes e as informações foram registradas em arquivos de protocolo do estudo. A coleta de dados foi realizada por uma estudante de graduação e uma da pós-graduação, previamente calibradas. A coleta durou dois meses e foram avaliados registros de 1984 a 2019. Os dados foram tratados no programa Microsoft Office Excel (version 2016) com análise descritiva dos dados. Resultados: Dos 920 prontuários analisados, 2,7% apresentavam pelo menos um dente supranumerário, com localização preferida na área superior anterior e na área parapremolar mandibular. O tipo mais prevalente foi o dente suplementar, com orientação de erupção normal e localização alveolar normal. Conclusão: Os dentes supranumerários da população estudada neste estudo mostraram pouca interferência na erupção ectópica da série dental normal. A maioria dos dentes supranumerários estava em posição de impactação. E, aproximadamente um terço dos dentes supranumerários apresentaram desvios de erupção.

Anterior open bite treated with palatine crib: a case report with cephalometric, speech and electromyography analyses

This case report describes an interceptive treatment of anterior open bite (AOB) with fixed palatine grid using clinical, cephalometric, electromyographic and speech analysis data. Case report: An 8-year-old girl, Angle Class I malocclusion presenting AOB. The complete orthodontic documentation was obtained and the perioral muscles were evaluated using the electromyography during blowing, sucking and smiling activities, before and after treatment. Speech acoustic evaluation was performed through the frequencies of the formants to assess the position of the tongue. Results: The AOB was corrected in six months with reduction of vertical transpass, decrease of cephalometric Angles 1: NA and 1: NB and increase of interincisal angle. During the smile movement, it was possible to observe the decrease of the muscular activity of the superior orbicularis muscle and the increase of the muscular activity of the inferior orbicularis. In the blow movement, there was a tendency to decrease muscle activity. Opposite directions were observed at the time of installation of the grid in the frequencies of the formants. When the grid was removed, the tongue was lowered and posteriorized in relation to the installation time. When compared the final and initial moments, it was noted a predominance of tongue lower position, besides posteriorization in some vowels and anteriorization in others. Conclusion: After the use of the fixed palatine crib as an interceptive treatment for AOB, the bite was closed and it was possible to observe an harmony in the patient profile and improvement in periorbital musculature and tongue positioning.

Objetivo: Este relato de caso descreve um tratamento interceptivo da mordida aberta anterior (MAA) com grade palatina fixa usando dados clínicos, cefalométricos, eletromiográficos e de fala. Relato do caso: Menina de 8 anos de idade apresentando maloclusão Classe I de Angle e MAA. A documentação ortodôntica completa foi obtida e os músculos periorais foram avaliados pela eletromiografia durante as atividades de sopro, sucção e sorriso, antes e após o tratamento. A avaliação acústica da fala foi realizada através das frequências dos formantes para avaliar a posição da língua. Resultados: O MAA foi corrigida em seis meses com redução do transpasse vertical, diminuição dos ângulos cefalométricos 1: NA e 1: NB e aumento do ângulo interincisivo. Durante o movimento do sorriso, foi possível observar a diminuição da atividade muscular do músculo orbicular superior e o aumento da atividade muscular do orbicular inferior. No movimento do sopro, houve uma tendência a diminuir a atividade muscular. Direções opostas foram observadas no momento da instalação da grade nas frequências dos formantes. Quando a grade foi removida, a língua foi abaixada e posteriorizada em relação ao tempo de instalação inicial do aparelho. Quando comparados os momentos final e inicial, observou-se predomínio da posição inferior da língua, além de posteriorização em algumas vogais e anteriorização em outras. Conclusão: Após o uso da grade palatina fixa como tratamento interceptivo para a MAA, a mordida foi fechada e foi possível observar harmonia no perfil da paciente e melhora da musculatura periorbital e posicionamento da língua.

Impaction of mandibular third molars after orthodontic treatment by the edgewise method: a retrospective study

Abstract This study aimed to determine the incidence of mandibular third molar (M3) impaction after orthodontic treatment by edgewise appliances, and identify possible determinant factors of M3 impaction. A retrospective cohort study was conducted with 1154 patients. Complete orthodontic records were analyzed pretreatment and posttreatment, considering the following variables: type of Angle malocclusion, treatment with or without extraction of first premolars, overbite, stage of dentition, M3 prior angulation and duration of orthodontic treatment. Impaction was determined after radiographic evidence of total closure of the root apex. The chi-square test and Poisson regression (p < 0.05) were used for statistical analysis with a hierarchical approach. Rate ratios (RR) and 95% confidence intervals (CI) were calculated. Mandibular M3 impaction incidence was 17%. Overbite equal to or greater than 4 mm (RR = 1.23, 95%CI: 1.11-1.26, p < 0.001), prior mesial angulation of M3 (RR = 0.59, 95%CI: 0.52-0.68, p < 0.001), non-extraction of first premolars (RR=1.06, 95%CI: 1.01-1.12, P=0.019) and orthodontic treatment time equal to or less than three years (RR = 0.94. 95%CI: 0.90-0.99, p < 0.014) were significantly associated with impacted M3. There was no correlation between the type of Angle malocclusion and the risk of impaction. In conclusion, the incidence of mandibular M3 impaction was considered low. The main pretreatment factors directly involved in impaction were mesioangulation of M3 and overbite equal to or greater than 4 mm. Orthodontic treatment with extraction of first premolars and treatment time greater than 3 years reduce the risk of impaction.

Transverse effects on the nasomaxillary complex one year after rapid maxillary expansion as the only intervention: A controlled study

The aim of this study was to assess by means of cone-beam computed tomography (CBCT) scans the transverse effects on the nasomaxillary complex in patients submitted to rapid maxillary expansion (RME) using Haas expander in comparison to untreated individuals. This prospective controlled clinical study assessed 30 subjects (18 boys and 12 girls) with mixed dentition and during pubertal growth. The treated group was submitted to RME with Haas expander, retention for six months and a six-month follow-up after removal. The control group matched the treated group in terms of age and sex distribution. CBCT scans were taken at treatment onset and one year after the expander was activated. Maxillary first molars (U6) width, right and left U6 angulation, maxillary alveolar width, maxillary basal width, palatal alveolar width, palatal base width, right and left alveolar angulation, palatal area, nasal base width, nasal cavity width and inferior nasal cavity area on the posterior, middle and anterior coronal slices were measured with Dolphin Imaging Software(r) 11.5, except for the first two variables which were performed only on the posterior slice. All transverse dimensions increased significantly (P < 0.05) in the treated group in comparison to the control, except for alveolar angulation and inferior nasal cavity area (P > 0.05). Results suggest that increase of molar, maxillary, palatal and nasal transverse dimensions was stable in comparison to the control group one year after treatment with RME.

OBJETIVO: avaliar, por meio de tomografias computadorizada de feixe cônico (TCFC), as dimensões transversais do complexo nasomaxilar de pacientes submetidos à expansão rápida da maxila (ERM) e sem intervenção. MÉTODOS: este estudo clínico prospectivo e controlado avaliou 30 indivíduos (18 meninos e 12 meninas) durante o período de crescimento puberal e dentição mista. O grupo tratado foi submetido à ERM com expansor de Haas, permanecendo 6 meses em contenção e sendo acompanhados por mais 6 meses após a remoção. O grupo controle foi acompanhado durante o mesmo tempo. Foram realizadas TCFC ao início e um ano após a fase ativa. Com o programa Dolphin Imaging 11.5, a largura entre os primeiros molares superiores (U6), angulação dos U6 direito e esquerdo, largura maxilar alveolar, largura maxilar basal, largura alveolar do palato, largura basal do palato, angulação alveolar direita e esquerda, área palatina, largura da base nasal, largura da cavidade nasal e área da cavidade nasal inferior foram obtidas em cortes coronais posterior, médio e anterior, com exceção das duas primeiras medidas, que foram obtidas apenas no corte coronal posterior. RESULTADOS: todas as medidas foram significativamente (p < 0,05) maiores no grupo da ERM, com exceção da angulação alveolar e da área da cavidade nasal, as quais não foram significativas (p > 0,05) entre os grupos. Os resultados sugerem que, um ano após a ERM, a dimensão transversal na cavidade nasal, maxila, palato e região dos molares são maiores do que em indivíduos não tratados. O protocolo de ERM utilizado foi eficaz na manutenção da dimensão transversal durante período de acompanhamento. .

Are self-ligating brackets related to less formation of Streptococcus mutans colonies? A systematic review

OBJECTIVE: To verify, by means of a systematic review, whether the design of brackets (conventional or self-ligating) influences adhesion and formation of Streptococcus mutans colonies. METHODS: Search strategy: four databases (Cochrane Central Register of Controlled Trials, Ovid ALL EMB Reviews, PubMed and BIREME) were selected to search relevant articles covering the period from January 1965 to December 2012. Selection Criteria: in first consensus by reading the title and abstract. The full text was obtained from publications that met the inclusion criteria. Data collection and analysis: Two reviewers independently extracted data using the keywords: conventional, self-ligating, biofilm, Streptococcus mutans, and systematic review; and independently evaluated the quality of the studies. In case of divergence, the technique of consensus was adopted. RESULTS: The search strategy resulted in 1,401 articles. The classification of scientific relevance revealed the high quality of the 6 eligible articles of which outcomes were not unanimous in reporting not only the influence of the design of the brackets (conventional or self-ligating) over adhesion and formation of colonies of Streptococcus mutans, but also that other factors such as the quality of the bracket type, the level of individual oral hygiene, bonding and age may have greater influence. Statistical analysis was not feasible because of the heterogeneous methodological design. CONCLUSIONS: Within the limitations of this study, it was concluded that there is no evidence for a possible influence of the design of the brackets (conventional or self-ligating) over colony formation and adhesion of Streptococcus mutans. .

OBJETIVO: verificar, por meio de uma revisão sistemática, se o design dos braquetes (convencionais ou autoligáveis) apresenta influência na aderência e formação de colônias de Streptococcus mutans. MÉTODOS: quatro bases de dados (Cochrane Central Register of Controlled Trials; Ovid ALL EMB Reviews; PubMed e BIREME) foram selecionadas para a busca por artigos relevantes, do período de janeiro de 1965 a dezembro de 2012. Os critérios de seleção foram inicialmente aplicados aos títulos e abstracts e o texto integral foi obtido de publicações que cumprira os critérios de inclusão. Dois revisores, de forma independente, extraíram os dados utilizando as palavras-chave "convencionais", "autoligados", "biofilme", "Streptococcus mutans" e "revisão sistemática" e avaliaram a qualidade metodológica dos estudos incluídos. No caso de divergência, foi adotada a técnica do consenso. RESULTADOS: a estratégia de busca resultou em 1.401 artigos. A classificação da relevância científica revelou alta qualidade dos 6 artigos elegíveis, cujos desfechos não foram unânimes em relatar a influência do design dos braquetes (convencionais ou autoligáveis) sobre a aderência e a formação de colônias de Streptococcus mutans, e que outros fatores como características dos tipos de braquetes, o nível de higiene bucal individual, colagem e idade dos indivíduos, podem ter maior influência. O tratamento estatístico foi inviável por causa do desenho metodológico heterogêneo. CONCLUSÕES: dentro das limitações do presente estudo, concluiu-se que não há evidência de uma possível influência do design dos braquetes (convencionais ou autoligáveis) sobre a aderência e a formação ...

Superficial morphology and mechanical properties of in vivo aged orthodontic ligatures

INTRODUCTION: The degradation of elastic ligatures in the oral environment results in the need of periodic replacement to maintain the optimal force during the orthodontic treatment. The purpose of this study was to perform a clinical prospective randomized study of the degradation of orthodontic elastomeric ligatures in the oral environment by scanning electron microscopy (SEM) and tensile strength test. METHOD: Two hundred elastic ligatures were randomly selected and placed around the brackets of 5 volunteers and removed in groups of 10, at different times (1, 2, 3, and 4 weeks). The control group was performed by another fifty ligatures which were not submitted to the oral degradation. The analyses were done by scanning electron microscopy (SEM) and strength mechanical test. RESULTS: The tensile strength test results showed reduction in the ultimate strength values after four weeks ageing in the oral environment and no statistical difference in the yield strength values (p < 0.05). The orthodontic elastomeric ligatures surface was significantly degraded in the oral cavity after four weeks. The elastomeric degradation began in the first week when the increase in the roughness could be detected just in some areas. Afterwards, the surface became gradually rougher and, after 4 weeks, it was totally rough with some crack areas. CONCLUSIONS: The elastic ligatures aged in the oral environment showed higher superficial degradation and lower loss of mechanical properties after the maximum experimental period.

INTRODUÇÃO: a degradação das ligaduras elásticas no ambiente bucal resulta na necessidade de substituição periódica para manter-se a força ótima durante o tratamento ortodôntico. OBJETIVO: a proposta desse trabalho foi realizar um estudo clínico prospectivo randomizado da degradação de ligaduras elásticas ortodônticas envelhecidas no ambiente bucal por microscopia eletrônica de varredura e por ensaio de tração. MÉTODOS: duzentas ligaduras foram randomicamente selecionadas e inseridas ao redor dos braquetes de 5 pacientes voluntários e, então, removidas, em grupos de 10, após diferentes tempos (1, 2, 3 e 4 semanas). O grupo controle foi formado por outras 50 ligaduras que não foram submetidas à degradação intrabucal. RESULTADOS: o ensaio mecânico demonstrou diminuição no limite de resistência à fratura após 4 semanas de degradação e não demonstrou diferença estatisticamente significativa no limite de elasticidade. A análise por microscopia eletrônica de varredura revelou que a superfície dos elastômeros tornou-se significativamente degradada após 4 semanas. A degradação teve início na primeira semana, quando o acréscimo de rugosidade superficial pôde ser detectado em algumas áreas. Posteriormente, a superfície tornou-se gradativamente mais rugosa, sendo que após 4 semanas toda a região apresentou-se rugosa e com algumas fraturas superficiais. CONCLUSÕES: as ligaduras elásticas envelhecidas no ambiente bucal apresentaram maior degradação superficial e menor perda das propriedades mecânicas após o período experimental máximo.

Influence of certain tooth characteristics on the esthetic evaluation of a smile

OBJECTIVE: To assess the influence of certain dental characteristics on the perception of smile esthetics by undergraduate dentistry students. METHODS: Ten digital photographs of a woman's smile were modified using Adobe Photoshop software. The following changes were performed: stain removal; incisal edge straightening; gingival leveling; closure of black triangles. A group of 60 undergraduate dental students evaluated the original photograph and the altered images using a visual analog scale to evaluate smile esthetics. Intraexaminer agreement was checked for 30 examiners using the Student t test; for casual error, the Dahlberg formula was used. Data were described as means and standard deviations, and reported in tables. RESULTS: There were no statistically significant differences between the first and second scores assigned by examiners (p>0.05) in any of the comparisons made. The results of systematic error for the method indicated that the measures obtained were reliable. ANOVA was used to test equality of means, and the level of significance was set at 5%. Equality of variances was evaluated using Levene's test, and results revealed that variances were equal. Multiple comparisons using the Tukey's test revealed statistical significance at a 5%level for the presence of black triangular space. No significant values were found for other comparisons. CONCLUSIONS: Some dental characteristics were perceived by undergraduate students, and the black triangular space was classified as the most unfavorable characteristic.

Immunosuppressants: implications in Orthodontics

INTRODUCTION: There are medications capable of affecting bone metabolism and the rate of tooth movement. Among these medications are the immunosuppressants, which act by repressing the action of T lymphocytes, however they can cause bone loss and consequently lead to osteoporosis. Osteoporosis is a common complication following kidney, heart, liver or lung transplantation. The immunosuppressant treatment for preventing organ rejection after transplantation, in general, includes glucocorticoids, cyclosporine, tacrolimus, and sirolimus. All these drugs can have jeopardizing effects on bone mineral homeostasis and consequently influence tooth movement. In recent years, however, the increasing use of immunosuppressants has raised questions about their effects on bone metabolism in patients undergoing orthodontic treatment. OBJECTIVE: The objective of this review study was to inform orthodontists about the influence of immunosuppressants on bone metabolism and tooth movement.

In situ evaluation of orthodontic elastomeric chains

The hypothesis tested in this study was that intraoral exposure of elastomeric chains alters their tensile strength. For such purpose, it was evaluated the in situ behavior of different elastomeric chains stretched for 3 weeks. Three kinds of elastomeric chains, Plastic chain (PC), Memory chain (MC) and Super slick chain (SSC), were randomly placed in 3 quadrants of 13 patient in a fixed distance of 16 mm and mean initial force of 180 g. Tensile testing was performed in an universal testing machine at different intervals: initial, 1 h, 24 h, 1 week, 2 weeks and 3 weeks. A two-way ANOVA test was performed to identify the influence of both material and time on the force decrease. A subsequent one-way ANOVAtest with the Tukey's post hoc test was used to identify statistically significant intragroup and intergroup remaining force (g and %) differences at 5% significance level. The effect of both the material and the time factors were significant. All groups showed significant force decrease after the 1-h period (23% for PC and 14% for MC and SSC). At the end of the 3-week period, the remaining force was 57% (96 g), 67% (129 g) and 71% (125 g) for PC, MC and SSC, respectively. In conclusion, intraoral exposure of elastomeric chains altered their tensile strength. In general, the greater force decrease occurred within the first hour. The remaining force of the enhanced chains measured at each time interval was greater than the conventional one (PC). After 3 weeks, only the enhanced chains maintained the force applied over 100 g.

A hipótese testada foi que a exposição dos elásticos em cadeia ao meio bucal altera sua força de tensão. Portanto, o objetivo deste estudo foi avaliar o comportamento, in situ, de diferentes cadeias elastoméricas quando tensionadas durante 3 semanas. Três tipos de elásticos em cadeia Plastic Chain (PC), Memory Chain (MC) e Super Slick Chain (SSC) foram inseridos aleatoriamente em 3 dos quadrantes de 13 pacientes com distância fixa de 16 mm e força inicial de 180 g. Foi realizado ensaio de tração em uma máquina de ensaio universal EMIC nos seguintes intervalos: inicial, 1 h, 24 h, 1 semana, 2 semanas e 3 semanas. O teste ANOVA a dois critérios foi aplicado para verificar a influência do material e do tempo na degradação da força. Subsequentemente, foi utilizado o teste ANOVA a um critério e pós-teste de Tukey para identificar diferenças estatísticas (p<0,05), intra-grupo e inter-grupo, na força remanescente (g e %). Tanto o material quanto o tempo tiveram efeito significativo na degradação da força. Todos os grupos mostraram diminuição significativa da força depois de 1 h sob tensão (23% para o PC e 14% para o MC e SSC). Ao final do período de 3 semanas, a força remanescente foi de 57% (96 g), 67% (129 g) e 71% (125 g) para o PC, MC e SSC, respectivamente. A exposição dos elásticos em cadeia ao meio bucal alterou a força de tensão. No geral, a maior diminuição da força ocorreu na primeira hora. A força remanescente testada em cada intervalo foi maior para os elásticos reforçados (MC e SSC) do que para o elástico convencional (PC). Após 3 semanas, apenas os elásticos reforçados mantiveram a força acima de 100 g.

Is miniscrew primary stability influenced by bone density?

Primary stability is absence of mobility in the bone bed after mini-implant placement and depends on bone quality among other factors. Bone quality is a subjective term frequently considered as bone density. The aim of this preliminary study was to evaluate bone density in two bovine pelvic regions and verify the primary stability of miniscrews inserted into them. Forty bone blocks were extracted from bovine pelvic bones, 20 from iliac and 20 from pubic bone, all of them containing cortical bone about 1 mm thick. Half of the sections extracted from each bone were designated for histological evaluation of bone density (trabecular bone area - TBA) and the other half for bone mineral density (BMD) evaluation by means of central dual-energy X-ray absorptiometry (DEXA). Then, twenty self-drilling miniscrews (INPÒ, São Paulo, Brazil) 1.4 mm in diameter and 6 mm long were inserted into the bone blocks used for BMD evaluation. Peak implant insertion torque (IT) and pull-out strength (PS) were used for primary stability evaluation. It was found that iliac and pubic bones present different bone densities, iliac bone being less dense considering BMD and TBA values (P > 0.05). However, the miniscrew primary stability was not different when varying the bone type (P < 0.05). IT and PS were not influenced by these differences in bone density when cortical thickness was about 1 mm thick.

Efeitos transversais da expansão rápida da maxila em pacientes com má oclusão de Classe II: avaliação por Tomografia Computadorizada Cone-Beam / Transverse effects of rapid maxillary expansion in Class II malocclusion patients: A Cone-Beam Computed Tomography study

OBJETIVO: avaliar por meio de Tomografia Computadorizada Cone-Beam (TCCB) os efeitos transversais, imediatos e após o período de contenção, da expansão rápida da maxila (ERM) em pacientes com má oclusão de Classe II. MÉTODOS: dezessete crianças (idade inicial média de 10,36 anos) com má oclusão de Classe II e deficiência transversal esquelética da maxila foram submetidas ao protocolo de ERM com aparelho expansor de Haas. TCCBs foram realizadas antes dos procedimentos clínicos (T1), imediatamente após a estabilização do parafuso expansor (T2) e após completados 6 meses de contenção e removido o aparelho (T3). Com o software Dolphin, foram possíveis a manipulação das imagens e as mensurações. O teste t de Student pareado foi utilizado para identificar significância estatística (p<0,05) entre os intervalos T2 e T1, T3 e T2, e T3 e T1. RESULTADOS: imediatamente após a ERM, ocorreu aumento significativo da largura maxilar basal, alveolar e dentária de 1,95mm, 4,30mm e 6,89mm, respectivamente, e inclinação vestibular dos primeiros molares direito (7,31º) e esquerdo (6,46º). Ao final do período de contenção, o aumento transversal foi mantido e a inclinação dentoalveolar retornou ao valor inicial. CONCLUSÕES: a ERM foi efetiva no aumento da dimensão transversa da maxila, tanto esquelético quanto dentário, sem causar inclinação dos molares de ancoragem em pacientes com má oclusão de Classe II.

OBJECTIVE: The aim of this study was to evaluate by Cone-Beam Computed Tomography (CBCT) transversal responses, immediately and after the retention period, to rapid maxillary expansion (RME), in Class II malocclusion patients. METHODS: Seventeen children (mean initial age of 10.36 years), with Class II malocclusion and skeletal constricted maxilla, underwent Haas´ protocol for RME. CBCT scans were taken before treatment (T1), at the end of the active expansion phase (T2) and after the retention period of six months (T3). The scans were managed in Dolphin software, where landmarks were marked and measured, on a coronal slice passing through the upper first molar. The paired Student´s t-test was used to identify significant differences (p<0.05) between T2 and T1, T3 and T2, and T3 and T1. RESULTS: Immediately after RME, the mean increase in maxillary basal, alveolar and dental width was 1.95 mm, 4.30 mm and 6.89 mm, respectively. This was accompanied by buccal inclination of the right (7.31°) and left (6.46°) first molars. At the end of the retention period, the entire transverse dimension increased was maintained and the dentoalveolar inclination resumed. CONCLUSIONS: The RME therapy was an effective procedure to increase transverse maxillary dimensions, at both skeletal and dentoalveolar levels, without causing inclination on anchorage molars in Class II malocclusion patients with skeletal constricted maxilla.

Analysis of mechanical properties and forces produced by transpalatal bars made from low-nickel alloy

Aim: This study evaluated assess the mechanical properties and forces produced by transpalatal bars made from low-nickel alloy. Methods: Using a template, a single operator made all transpalatal bars from 0.032" and 0.036" wires of two different alloys, thus originating four groups, namely: A8 (0.032" conventional stainless steel), B8 (0.032" low-nickel stainless steel), A9 (0.036" conventional stainless steel), and B9 (0.036" low-nickel stainless steel). The bars were then activated and mounted onto a device developed to serve as a support for mechanical assay in a universal testing machine (Emic DL 10.000). The values of resilience and ductility were obtained using the Origin 8 software. Results: No statistically significant differences (P > 0.05) were observed between Groups A8 and B8 neither between A9 and B9 for 0.5-, 1.0-, and 5-mm deformations. However, statistically significant differences (P < 0.05) were found in all groups for 15-mm deformation. Groups B8 and B9 showed greater ductility and resilience compared to groups A8 and A9, respectively. Conclusions: Low-nickel stainless steel transpalatal bars release the same amount of force for activations less than 10 mm compared to those made from conventional stainless steel. Mechanically, the low-nickel stainless steel bars are more ductile and resilient.

Long-term fluoride release from resin-reinforced orthodontic cements following recharge with fluoride solution

The aim of this study was to test the hypothesis that there is no difference in the fluoride release behavior of resin-reinforced glass ionomer cements before or after fluoride recharge. The materials were divided into 5 groups: 2 resin-reinforced glass ionomer cements used for attaching orthodontic bands, that is, group FOB (Fuji Ortho Band) and group MCB (Multi-Cure Glass Ionomer Orthodontic Band Cement); 2 resin-reinforced glass ionomer cements and a composite used for bonding orthodontic brackets, that is, group OGLC (Ortho Glass LC), group FOLC (Fuji Ortho LC), and group TXT (Transbond XT), respectively. Fluoride release was measured during a 60-day period by using selective ion electrodes connected to an ionic analyser. After 4 weeks, the samples were exposed to 0.221 percent sodium fluoride solution. The results showed that cements achieved a maximum fluoride release 24 h after initial setting. No statistically significant differences were observed between groups FOB and OGLC regarding the amount of released fluoride following fluoride recharge from day 31 to day 36 (p>0.05). In conclusion, FOB and OGLC cements showed a higher capacity of capturing and releasing fluoride compared to the other cements studied.

O objetivo deste estudo foi testar a hipótese que não há diferença no desempenho dos cimentos de ionômero de vidro reforçados com resina entre si quanto à liberação de flúor antes e após recarga com flúor. Os materiais foram divididos em 5 grupos: 2 cimentos de ionômero de vidro reforçados com resina utilizados para cimentação de bandas ortodônticas: Grupo FOB (Fuji Ortho Band) e Grupo MCB (Multi-Cure Glass Ionomer Orthodontic Band Cement); 2 cimentos de ionômero de vidro reforçados com resina e 1 compósito utilizados para colagem de bráquetes ortodônticos: Grupo OGLC (Ortho Glass LC), Grupo FOLC (Fuji Ortho LC); e Grupo TXT (Transbond XT), respectivamente. A liberação de flúor foi medida durante 60 dias, através de eletrodo íon seletivo conectado a um analisador de íons. Após 4 semanas, os corpos de prova foram expostos a solução de fluoreto de sódio à 0,221 por cento. Os resultados evidenciaram que os cimentos atingiram o pico máximo de liberação de flúor com 24 h após presa inicial. Não houve diferença estatisticamente significante entre a quantidade de flúor liberado após as recargas de fluoreto de sódio entre os grupos FOB e OGLC do 31° ao 36° dia (p>0.05). Concluindo os cimentos FOB e OGLC apresentaram maior capacidade de captação e liberação de flúor comparada aos outros CIVRRs.

Avaliação por tomografia computadorizada helicoidal dos efeitos da expansão rápida da maxila no posicionamento condilar em pacientes com mordida cruzada posterior funcional / Evaluation with helicoidal computed tomography of rapid maxillary expansion effects in the condylar position of patients with functional posterior crossbite

OBJETIVO: este estudo clínico avaliou, por meio da tomografia computadorizada helicoidal, os efeitos da expansão rápida da maxila no posicionamento condilar de pacientes com mordida cruzada posterior funcional na fase da dentadura mista. MÉTODOS: dez pacientes com faixa etária entre os 7 anos e 2 meses e os 11 anos e 2 meses - apresentando mordida cruzada posterior funcional, com desvio da linha média de pelo menos 2,5mm para o lado do cruzamento - foram tratados com expansão rápida da maxila. Após a obtenção de cortes tomográficos sagitais da articulação temporomandibular, as medidas dos espaços articulares anterior, posterior e superior foram realizadas e o posicionamento relativo do côndilo foi calculado. Utilizando-se cortes tomográficos axiais, avaliou-se o posicionamento anteroposterior e transversal dos côndilos em relação às estruturas da base craniana. RESULTADOS: foram identificadas diferenças significativas, antes do tratamento, entre os espaços articulares posteriores, na posição relativa do côndilo e um posicionamento mais anterior e mais próximo ao plano sagital mediano do côndilo do lado não-cruzado. Após o tratamento, não foram evidenciadas diferenças significativas nessas medidas. CONCLUSÕES: após a expansão rápida da maxila, um posicionamento mais centralizado dos côndilos nas fossas articulares foi observado, além de uma maior simetria anteroposterior e transversal entre os mesmos.

AIM: This clinical study evaluated, through helicoidal computed tomography (CT), the effects of rapid maxillary expansion in the condylar position of patients with functional posterior crossbite in mixed dentition stage. METHODS: Ten patients aged between 7 years and 2 months and 11 years and 2 months were selected. This patients which presented functional unilateral posterior crossbite with mandibular midline deviation of at least 2.5mm to the crossbite side were submitted to rapid maxillary expansion. After obtaining sagittal CT slices of the temporomandibular joints, measurements of the anterior, posterior and superior joint spaces were carried out and the relative positioning of the condyle was calculated. Axial slices of the temporomandibular joint were also used to evaluate the anteroposterior and transversal position of the condyles in relation to the cranial base structures. RESULTS: Before treatment, significant differences were observed in the posterior joint spaces, in the relative positioning of the condyle and with the non-crossbite side condyle displaced more anteriorly and medially in relation to midsagittal line. After treatment there was no statistically significant difference. CONCLUSION: After the rapid maxillary expansion, a more centralized position of the condyles in the joint cavities was observed, and a greater anteroposterior and transverse symmetry between them.

Evaluation of palatal arches made from low-nickel stainless steel wire

Aim: To test the hypothesis that there is no difference between stainless steel wires and low-nickel stainless steel ones regarding their mechanical behavior. Force, resilience and elasticity modulus produced by Coffin, “W” arch, and Quad-helix appliances made of 0.032-inch and 0.036-inch wires were evaluated. Methods: Fifteen appliances of each type (Coffin, “W” arch, and Quad-helix) were made according to metal alloy and wire thickness. All arches (12 groups of 15 appliances each) were submitted to mechanical compression test by using an EMIC DL-10000 machine simulating activations of 5, 8, 10, and 12 mm. Analysis of variance with multiple comparisons and Tukey’s test were used (P < 0.05) for analyzing statistically force and resilience data. Results: The results showed that mechanical properties depended on shape of the appliance, diameter of the wire, amount of activation, and metal alloy. Conclusions: Appliances made from lownickel stainless steel alloy had higher release of force, resilience and elasticity modulus compared to those made of stainless steel alloy.

Influência dos imunossupressores no metabolismo ósseo e movimento dentário: revisão de literatura / Influence of immunosuppressants on bone metabolism and tooth movement: a literature review

O objetivo desta revisão de literatura é discutir a influência dos imunossupressores no metabolismo ósseo e movimento dentário em Ortodontia. O movimento dentário ocorre em função do processo de remodelação do tecido ósseo e do ligamento periodontal. Existem medicamentos capazes de afetar o metabolismo ósseo e a taxa de movimento dentário, tais como os imunossupressores. Os imunossupressores agem reprimindo a ação dos linfócitos T, podem causar perda óssea e levar a um quadro de osteoporose, a qual é uma complicação comum após os transplantes de rim, coração, fígado e pulmão. Os esquemas imunossupressores para evitar a rejeição do órgão enxertado após o transplante frequentemente incluem glicocorticóides, ciclosporina A, tacrolimus e sirolimus, os quais podem causar efeitos danosos sobre a homeostase mineral óssea. O movimento dentário é dependente da força ortodôntica, dose e duração da terapia imunossupressora, além da resposta individual de cada indivíduo. Assim, todos os pacientes transplantados e usuários de imunossupressores deveriam ser submetidos a monitoramento e prevenção de perda óssea antes e durante o tratamento ortodôntico.

The objective of this literature review is to discuss the influence of immunosuppressants on bone metabolism and tooth movement in Orthodontics. Tooth movement occurs as a result of bone and periodontal ligament remodeling. Some medications such as immunosupressants can affect bone metabolism and the rate of tooth movement. Immunosupressants act by repressing the action of T lymphocytes, may cause bone loss, and lead to osteoporosis, which is a common complication following kidney, heart, liver, or lung transplantation. The use of immunosuppressants to prevent rejection after organ transplantation includes glucocorticoids, cyclosporine A, tacrolimus, and sirolimus, which may cause damaging effects on the bone mineral homeostasis. Tooth movement depends on orthodontic force, dosage, and duration of immunosuppressive therapy, and individual response of each patient. Therefore, all patients who have received transplants should be closely monitored to prevent bone loss before and during orthodontic treatment.

Histomorphometric study of alveolar bone after therapy with immunosuppressant FK506

Aim: Several medications affect bone metabolism and the rate of tooth movement. The objective of the present study was to test the hypothesis that treatment with immunosuppressant tacrolimus (FK506) can interfere with bone turnover, decreasing the rate of tooth movement. Methods: Sixty male Wistar rats were divided into four groups of 15 animals each: Group 1: rats subjected to orthodontic movement plus treatment with saline solution vehicle; Group 2: rats subjected to orthodontic movement plus treatment with FK506; Group 3: rats treated with FK506 only; and Group 4: rats treated with saline solution vehicle only. The FK506 dose was 2 mg/kg/day. The treatment was initiated 14 days before the appliance installation and then kept for up to 14 days. In addition to the administration of the immunosuppressive drug, 10 mg/kg of oxytetracycline were injected at intervals of three days in order to show osteoblastic activity and bone growth at a histological level. Results: Histomorphometrical measurements showed greater tooth movement in Group 1 than in Group 2 at all periods (days 3, 7 and 14), though significant difference (p < 0.05) was observed only on days 7 and 14. Conclusions: FK506 significantly influenced the rate of tooth movement in rats subjected to the application of this medication.