ABSTRACT Introduction: Head and neck cancer is considered one of the most common types, and its treatment includes radiotherapy, which can trigger side effects and undesirable sequelae in the oral cavity and dental tissues. Objective: This study aimed to make an in vitro evaluation of the shear strength and failure mode of ceramic orthodontic brackets bonded with two different composites in enamel submitted to ionizing radiation. Methods: After the study was approved by the Research Ethics Committee, 60 healthy human premolars were selected and divided into two groups, based on the absence or presence of ionizing irradiation of the enamel. The fragments were thermocycled and then randomly subdivided into two subgroups, according to the composite used for bonding the ceramic brackets (Inspire Ice - Ormco) to the enamel (n = 15): Transbond XT composite (3M), and Light Bond composite (Reliance). After 24 hours, the specimens were submitted to the shear strength test, and the failure mode was analyzed using a stereomicroscope and confocal microscopy. The shear strength data were submitted to two-way ANOVA, considering a significance level of 5%. Results: The groups submitted to radiation presented lower shear strength values (4.48MPa) than those not irradiated (9.23MPa) (p< 0.001), and the tested composites were not statistically different (p= 0.078). Regarding the fracture mode, all the groups presented mostly adhesive fractures. Conclusion: It was concluded that ionizing radiation negatively affects the adhesion of ceramic brackets, regardless of the composite used for bonding.

RESUMO Introdução: A expansão rápida da maxila assistida cirurgicamente (ERMAC) promove expansão em pacientes esqueleticamente maduros. Essa técnica é efetiva; entretanto, alguns efeitos colaterais ainda são desconhecidos. Objetivos: Avaliar a presença de defeitos alveolares (deiscência e fenestração) em pacientes submetidos à ERMAC. A hipótese nula testada foi que a ERMAC não influenciaria o número de deiscências e fenestrações. Métodos: Foi realizado um estudo quase-experimental de uma amostra de conveniência de 279 dentes superiores, de 29 pacientes que foram avaliados por meio de tomografia computadorizada de feixe cônico (TCFC) em T1 (antes da ERMAC), T2 (após expansão) e T3 (após contenção). Caninos, primeiros e segundos pré-molares, primeiros e segundos molares foram examinados em cortes axiais, coronais e sagitais. As raízes vestibulares desses dentes foram avaliadas da face mesial até a distal. Resultados: Todas as análises estatísticas foram realizadas usando os softwares SAS 9.3 e SUDAAN. O alfa usado no estudo foi de 0,05. Os defeitos alveolares aumentaram significativamente de T1 (69,0%) para T2 (96,5%) e T3 (100%). Deiscências aumentaram 195% (risco relativo de 2,95%) no final da expansão (T2). Após contenção (T3), os pacientes tiveram, em média, 4,34 vezes mais chance de desenvolver deiscência (334% de aumento). As fenestrações não aumentaram de T1 para T2 (p= 0.0162, 7.9%) e diminuíram de T2 para T3 (p = 0.0259, 4,3%). A presença de fenestrações em T1 foi um preditor significativo para o desenvolvimento de deiscências em T2 e T3. Deiscências aumentaram significativamente em todos os dentes, exceto nos segundos molares. Conclusão: A hipótese nula foi rejeitada. Após a ERMAC, o número de deiscências aumentou e o de fenestrações diminuiu. Defeitos alveolares prévios foram preditores de deiscências após a ERMAC.

ABSTRACT Introduction: Surgically Assisted Rapid Palatal Expansion (SARPE) promote maxillary expansion in skeletally mature patients. This technique is effective; however, some side effects are still unknown. Objectives: evaluate the presence of alveolar defects (dehiscences and fenestrations) in patients submitted to the SARPE. The null hypothesis tested was: SARPE does not influence the number of dehiscences and fenestrationss. Methods: A retrospective quasi-experiment study of a convenience sample of 279 maxillary teeth, in 29 patients evaluated with Cone Beam Computed Tomography (CBCT) at T1 (before SARPE), T2 (after expansion) and T3 (after retention), was performed. The examined teeth were: canines, first and second premolars, first and second molars. in axial, coronal, and cross-sectional views. The evaluations involved viewing slices from mesial to distal of the buccal roots. Results: All statistical analyses were performed using SAS 9.3 and SUDAAN softwares. Alpha used in the study was 0.05. Alveolar defects increased statistically from T1 (69.0%) to T2 (96.5%) and T3 (100%). Dehiscences increased 195% (Relative Risk 2.95) at the end of expansion (T2). After retention (T3), individuals were on average 4.34 times more likely to develop dehiscences (334% increase). Fenestrations did not increase from T1 to T2 (p = 0.0162, 7.9%) and decreased from T2 to T3 (p = 0.0259, 4.3%). Presence of fenestrations at T1 was a significant predictor for the development of dehiscences in T2 and T3. Dehiscences increased significantly in all teeth, except second molars. Conclusion: The null hypothesis was rejected. After SARPE the number of dehiscences increased and fenestrations decreased. Previous alveolar defects were predictor for dehiscences after SARPE.

Resumo O objetivo do estudo foi avaliar a resistência de união ao cisalhamento da colagem (RCC), o índice de remanescente de adesivo (IRA) e o modo de fratura de bráquetes cerâmicos com retenção química e mecânica colados com diferentes compositos e irradiados com laser de CO2. A hipótese nula testada foi que bráquetes colados com diferentes compósitos e irradiados com laser de CO2 apresentam valores semelhantes de RCC. Noventa pré-molares humanos foram divididos em 6 grupos (n=15): 2 controles e 4 experimentais que se diferenciaram pelo tipo de bráquete ceramic (Fascination and Mystique) e pelo compósito de fixação (Transbond XT e Z 250). Nos quatro grupos experimentais, os bráquetes foram irradiados com laser de CO2 com 10W por 3 segundos anteriormente ao teste de RCC. O IRA das superficies de esmalte foram avaliados após a descolagem e submetidos a análise em microscopia electrônica de varredura (MEV). Para análise estatística foram utilizados ANOVA e o teste de mann-Whitney. Os grupos laser mostraram valores de RCC menores que os grupos não irradiados (controles) (p<0.05). Os bráquetes com retenção mecânica (Mystique) mostraram alta RCC (p<0.05) e o compósito Z 250 obteve os mais baixos valores de RCC após irradiação com laser. Os grupos colados com o compósito Z 250 apresentaram os mais altos escores do IRA. O modo de fratura mais prevalente foi a adesiva. A hipótese nula foi rejeitada. O laser de CO2 foi eficaz para diminuir os valores de RCC e facilitou a descolagem dos bráquetes cerâmicos de retenção química e mecânica

Abstract This study evaluated shear bond strength (SBS), adhesive remnant index (ARI) and fracture mode of chemically and mechanically retained ceramic brackets bonded with different composite resins and irradiated with CO2 laser. The null hypothesis was that ceramic brackets bonded with different composite resins and irradiated with CO2 laser would have similar SBS values. Ninety human premolars were divided into four experimental groups according to the combination of type of composite resin (Transbond XT and Z 250) and type of ceramic bracket (Fascination and Mystique), and two control groups (n=15). In the four experimental groups, the brackets were irradiated with CO2 laser at 10 W for 3 seconds before SBS testing. Enamel surface ARI was calculated after debonding under electron microscopy scanning. ANOVA and the Mann-Whitney test were used for statistical analysis. The laser groups had lower SBS values than the non-irradiated groups (control) (p<0.05). The mechanically retained brackets (Mystique) had the higher (p<0.05) and Z250 had the lower SBS values after CO2 laser irradiation. The groups bonded with Z250 had the highest ARI. Adhesive fractures were the most prevalent. The null hypothesis was rejected. CO2 laser decreased SBS efficiently and facilitated debonding of mechanically and chemically retained ceramic brackets.

RESUMO Introdução: Embora os braquetes autoligados presumivelmente proporcionem melhores condições de higiene, nenhum consenso foi alcançado até o momento. Objetivo: O objetivo do presente estudo foi avaliar, em um delineamento experimental in vitro, a aderência de Streptococcus mutans em braquetes autoligados e convencionais de diferentes fabricantes e tipos de ligaduras. Métodos: Quatro marcas comerciais de braquetes metálicos de pré-molares superiores foram testadas (Abzil®; Morelli®; 3M Unitek®; e GAC®). Cada marca foi subdividida em três grupos, que variaram de acordo com o tipo de ligadura e o modelo do braquete (metálico, elástico e autoligado), totalizando doze grupos, compostos por seis braquetes cada. Os braquetes previamente esterilizados foram, inicialmente, imersos em saliva por uma hora, sendo posteriormente lavados e adicionados em uma suspensão bacteriana, mantida em aerobiose por 72 horas. As bactérias aderidas foram, então, separadas e quantificadas por contagem de unidades formadoras de colônias (UFC/mL) após 48 horas de crescimento. Os grupos foram comparados pelos testes post-hoc de Kruskal-Wallis e Dunn (p< 0,05). Resultados: Independentemente da marca comercial, os braquetes autoligados apresentaram significativamente menos UFC/mL. Porém, de acordo com as comparações realizadas dentro de cada marca comercial, apenas os modelos autoligados Abzil® apresentaram adesão de biofilme significativamente menor. Entre todos os modelos autoligados, os braquetes GAC® apresentaram a maior taxa de adesão bacteriana. Conclusões: Os braquetes autoligados provavelmente apresentam menores taxas de adesão do biofilme. Particularmente, os braquetes autoligados Abzil® e GAC® têm menor probabilidade de acumular biofilme. Embora tais resultados sejam derivados de um estudo in vitro, os clínicos podem reconhecer os achados relativos à adesão bacteriana como uma das características relevantes a serem consideradas durante a seleção dos braquetes.

ABSTRACT Introduction: Although self-ligating brackets presumably provide better hygiene conditions, no consensus has been reached so far. Objective: Therefore, the objective of this study was to evaluate, in an in vitro experimental design, the adherence of Streptococcus mutans (SM) in self-ligating and conventional brackets of different manufacturers and ligature types. Methods: Four commercial brands of maxillary premolar metal brackets were tested (Abzil®; Morelli®; 3M Unitek®; and GAC®). Each one was subdivided into three groups, which varied according to the type of ligature and bracket model (metallic, elastic, and self-ligating), totalizing twelve groups, composed of six brackets each. Previously sterilized brackets were initially immersed in saliva for one hour, and subsequently washed and added in a bacterial suspension, maintained in aerobiosis for 72 hours. The adhered bacteria were then separated and quantified by colony forming units (CFU/mL) counting after 48 hours of growth. The groups were compared by Kruskal-Wallis and Dunn post-hoc tests (p< 0.05). Results: Regardless of the commercial brand, self-ligating brackets had significantly less CFU/mL. However, according to comparisons performed within each commercial brand, only Abzil® self-ligating brackets had significantly lower biofilm adhesion. Among all of the self-ligating models, GAC® brackets presented the highest bacterial adhesion rate. Conclusions: Self-ligating brackets are likely to present lower rates of biofilm adhesion. Particularly, Abzil® and GAC® self-ligating brackets are less likely to accumulate biofilm. Although such results are derived from an in vitro study, practitioners might acknowledge findings concerning bacterial adhesion as one of the relevant features to be considered during bracket selection.

RESUMO Introdução: A mordida cruzada posterior esquelética (MCPE) apresenta etiologia multifatorial, podendo ser causada por hábitos parafuncionais, posição atípica da língua, perdas dentárias e assimetrias esqueléticas transversais da maxila ou da mandíbula. Alterações faciais podem estar presentes quando há envolvimento esquelético, levando a estética desfavorável. O tratamento da MCPE, quando diagnosticada no paciente adulto, requer abordagem correta, com identificação do fator etiológico. Entre as técnicas utilizadas para correção da MCPE em pacientes esqueleticamente maduros, cita-se, em especial, a Expansão Rápida de Maxila Assistida Cirurgicamente (ERMAC). Essa modalidade tem se mostrado bastante eficiente na correção dos problemas transversais, apresenta estabilidade e pode ser realizada em ambiente ambulatorial ou hospitalar. Objetivo: O objetivo do presente trabalho será discutir os resultados da ERMAC assimétrica para correção da MCPE unilateral associada a assimetria transversal da mandíbula. Conclusão: A alternativa de tratamento utilizada no caso relatado mostrou-se bastante eficiente. Ao fim do tratamento, o paciente apresentou adequada oclusão e boa estética facial.

ABSTRACT Introduction: Skeletal posterior crossbite (SPCB) has a multifactorial etiology, as it may be caused by parafunctional habits, atypical position of the tongue, tooth losses and maxillary or mandibular transverse skeletal asymmetries. Skeletal involvement may lead to facial changes and an unfavorable aesthetic appearance. The treatment of SPCB diagnosed in an adult patient should be correctly approached after the identification of its etiologic factor. Surgically-assisted rapid maxillary expansion (SARME), one of the techniques used to correct SPCB in skeletally mature individuals, is an efficient and stable procedure for the correction of transverse discrepancies that may be performed in the office or in a hospital. Objective: This study discusses the results of asymmetrical SARME used to correct unilateral SPCB associated with transverse mandibular asymmetry. Conclusion: The treatment alternative used in the reported case was quite effective. At the end of the treatment, the patient presented adequate occlusion and facial aesthetics.

Abstract Objectives: Miniscrew has been frequently used, considering that anchorage control is a critical point in orthodontic treatment, and its failure, the main adverse problem. Using two groups of stable (successful) and unstable (failed) mini-implants, this in vivo study aimed to quantify proinflammatory cytokines IL-1 α, IL-6, IL-17, and TNF-α and osteoclastogenesis marker RANK, RANKL, and OPG in gingival tissue, using the real-time polymerase chain reaction technique. Methodology: Thirteen patients of both sexes (11-49 years old) under orthodontic treatment were selected, obtaining 11 successful and 7 failed mini-implants. The mini-implants were placed and removed by the same surgeon, in both jaws. The mean time of permanence in the mouth was 29.4 months for successful and 7.6 months for failed mini-implants. At removal time, peri-mini-implant gingival tissue samples were collected and processed for quantification of the proinflammatory cytokines and osteoclastogenesis markers. Nonparametric Wilcoxon rank-sum test considering the clusters and Kruskal-Wallis test were used for statistical analysis (α=0.05). Results: No significant difference (p>0.05) was observed between the groups for either quantification of cytokines or osteoclastogenesis markers, except for IL-6 (p<0.05). Conclusions: It may be concluded that the expression of IL-1α, IL-17, TNF-α, RANK, RANKL, and OPG in peri-implant gingival tissue were not determinant for mini-implant stability loss, but the higher IL-6 expression could be associated with mini-implant failure.

Abstract Objectives Enamel demineralization is among the main topics of interest in the orthodontic field. Self-ligating brackets have been regarded as advantageous in this aspect. The aim of this study was to evaluate the break homeostasis in the oral environment and the levels of microorganisms associated with dental caries among the different types of brackets. Material and Methods Twenty patients received two self-ligating brackets: In-Ovation®R, SmartClipTM, and one conventional GeminiTM. Saliva was collected before bonding (S0), 30 (S1) and 60 (S2) days after bonding. One sample of each bracket was removed at 30 and 60 days for the in situ analysis. Checkerboard DNA-DNA Hybridization was employed to evaluate the levels of microbial species as-sociated with dental caries. Data were evaluated by nonparametric Friedman and Wilcoxon tests at 5% significance level. Results The salivary levels of L. casei (p=0.033), S. sobrinus (p=0.011), and S. sanguinis (p=0.004) increased in S1. The in situ analyses showed alteration in S. mutans (p=0.047), whose highest levels were observed to the In-Ovation®R. Conclusions The orthodontic appliances break the salivary homeostasis of microorganisms involved in dental caries. The contamination pattern was different between self-ligating and conventional brackets. The In-Ovation®R presented worse performance considering the levels of cariogenic bacterial species.

RESUMO Objetivo: avaliar se a adição de radiografias interproximais verticais (IV) e/ou oclusais (OC) pode alterar o julgamento inicial sobre a posição final dos mini-implantes ortodônticos (MI) baseado somente na radiografia periapical (PA). Métodos: foram realizadas análises subjetivas e objetivas. Imagens radiográficas de 26 regiões contendo MI foram divididas em quatro grupos: PA, PA+IV, PA+OC e TODAS (PA+IV+OC). Na análise subjetiva, cinco observadores foram convidados a avaliar se a posição do MI era favorável para o seu sucesso, utilizando questionários com uma escala de quatro pontos para respostas: 1 = definitivamente não favorável; 2 = provavelmente não favorável; 3 = provavelmente favorável; ou 4 = definitivamente favorável. Cada grupo contendo conjuntos de imagens foi apresentado aos observadores em quatro sessões diferentes. Adicionalmente, uma avaliação objetiva comparou as distâncias horizontais entre a ponta do MI e a raiz dentária mais próxima ao dispositivo na PA e IV. Resultados: a maioria dos observadores (3 de 5) mudou seu julgamento inicial sobre a posição do MI baseado na PA quando radiografias adicionais foram analisadas. Diferenças entre os grupos (ou seja, PA vs PA+IV; PA vs PA+OC; e PAvsTODAS) foram estatisticamente significativas para esses observadores. Para aqueles que mudaram seu julgamento sobre a posição do MI, o nível de confiança das respostas aumentou, diminuiu ou foi mantido, não indicando um padrão. Houve diferença estatisticamente significante entre as distâncias da ponta do MI para a raiz mais próxima ao dispositivo na PA e IV. Conclusão: considerando-se as limitações desse estudo, concluiu-se que imagens radiográficas adicionais podem alterar o julgamento sobre a posição final de MI sem, necessariamente, aumentar o grau de certeza de tal julgamento.

ABSTRACT Objective: This study aimed to assess if additional vertical bitewing (VBW) and/or occlusal (OC) radiographs may change initial judgment based only on periapical radiograph (PAR) about the final position of orthodontic mini-implants (OMI). Methods: Subjective and objective analyses were performed. Radiographic images of 26 OMI were divided into four groups: PAR, PAR+VBW, PAR+OC and ALL (PAR+VBW+OC). For subjective analysis, five observers were asked to assess if the position of OMI was favorable to its success, using questionnaires with a four-point scale for responses: 1= definitely not favorable, 2= probably not favorable, 3= probably favorable, or 4= definitely favorable. Each group containing sets of images was presented to them in four different viewing sessions. Objective evaluation compared horizontal distances between OMI tip and the root nearest to the device in PAR and VBW. Results: Most of observers (3 out of 5) changed their initial judgment based on PAR about OMI position when additional radiographs were analyzed. Differences between groups (i.e. PAR vs. PAR+VBW; PAR vs. PAR+OC; and, PARvs.ALL) were statistically significant for these observers. For those that changed their judgment about OMI position, confidence level could significantly increase, decrease or even be maintained, not indicating a pattern. There was no agreement for distances between OMI tip and the root nearest to the device in PAR and VBW. Conclusion: Considering the limitations of the study, it is concluded that additional radiographic images may change the judgement about OMI final position without necessarily increasing the degree of certainty of such judgment.

Resumo Pacientes submetidos a tratamento radioterápico apresentam maior suscetibilidade à cárie dentária e o uso de aparelho aumenta esse fator de risco devido ao acúmulo de biofilme dental ao redor dos bráquetes. Assim, o objetivo deste estudo foi avaliar a resistência ao cisalhamento de bráquetes ortodônticos colados com cimento de ionômero de vidro convencional (CIV) e o modificado por resina (CIVMR), devido à capacidade de liberação de flúor desse material em dentes permanentes irradiados. Noventa pré-molares humanos foram divididos em 6 grupos (n=15), de acordo com o materila de colagem e com o uso ou não de radiação: RC: Transbond XT; CIVMR: Fuji Ortho LC; RMGIC: Ketac Cem Easymix. Os grupos for irradiados (I) ou não-irradiados (NI) previamente à colagem dos bráquetes. Os espécimes foram submetidos a doses fracionadas de radiação de 2 Gy/dia, durante 5 dias consecutivos, por 6 semanas. Depois da termociclagem e radioterapia, os bráquetes foram colados sobre os espécimes com Transbond XT, Fuji Ortho LC e Ketac Cem Easymix. Depois de 24 h, os espécimes foram sumetidos ao teste de resistência ao cisalhamento. A imagem da superfície do esmalte (classificado pelo Índice de Remanescente Adesivo-IRA) também foi avaliada. O IRA foi distribuido em tabelas de contingência e analisado quanto à frequência entre grupos/subgrupos. O teste de resistência ao cisalhamento foi avaliado por ANOVA e pós-teste de Tukey. CIVMR apresentou os menores valores de adesão entre os grupos (p<0,05). Entre os grupos irradiados e não-irradiados não houve diferença estatística significante (p>0,05). Quanto ao IRA, RC-I apresentou maior retenção de compósito na superfície do esmalte do que os demais subgrupos. CIVMR pode ser utilizado para colagem de bráquetes metálico e apresentou IRA aceitável para práticas clínicas.

Abstract Patients undergoing radiotherapy treatment present more susceptibility to dental caries and the use of an orthodontic device increases this risk factor due to biofilm accumulation around the brackets. The objective of this study was to evaluate the shear bond strength to irradiated permanent teeth of orthodontic brackets bonded with conventional glass ionomer cement and resin-modified glass ionomer cement due to the fluoride release capacity of these materials. Ninety prepared human premolars were divided into 6 groups (n=15), according to the bonding material and use or not of radiation: CR: Transbond XT composite resin; RMGIC: Fuji Ortho LC conventional glass ionomer cement; GIC: Ketac Cem Easymix resin-modified glass ionomer cement. The groups were irradiated (I) or non-irradiated (NI) prior to bracket bonding. The specimens were subjected to a fractioned radiation dose of 2 Gy over 5 consecutive days for 6 weeks. After the radiotherapy, the brackets were bonded on the specimens with Transbond XT, Fuji Ortho LC and Ketac Cem Easymix. After 24 h, the specimens were subjected to shear bond strength test. The image of enamel surface (classified by Adhesive Remnant Index - ARI) was also evaluated and its frequency was checked among groups/subgroups. The shear bond strength variable was evaluated with ANOVA and Tukey’s post-hoc test. GIC group showed the lowest adhesion values among the groups (p<0.05). There was no statistically significant difference among non-irradiated and irradiated groups (p>0.05). As for the ARI, the CR-I group showed the highest material retention on enamel surface among the irradiated groups. RMGIC group showed the highest values for shear bond strength and presented ARI acceptable for clinical practices.

Abstract Bacterial endotoxin (LPS) adhesion to orthodontic brackets is a known contributing factor to inflammation of the adjacent gingival tissues. Objective The aim of this study was to assess whether LPS adheres to orthodontic adhesive systems, comparing two commercial brands. Material and Methods Forty specimens were fabricated from Transbond XT and Light Bond composite and bonding agent components (n=10/component), then contaminated by immersion in a bacterial endotoxin solution. Contaminated and non-contaminated acrylic resin samples were used as positive and negative control groups, respectively. LPS quantification was performed by the Limulus Amebocyte Lysate QCL-1000™ test. Data obtained were scored and subjected to the Chi-square test using a significance level of 5%. Results There was endotoxin adhesion to all materials (p<0.05). No statistically significant difference was found between composites/bonding agents and acrylic resin (p>0.05). There was no significant difference (p>0.05) among commercial brands. Affinity of endotoxin was significantly greater for the bonding agents (p=0.0025). Conclusions LPS adhered to both orthodontic adhesive systems. Regardless of the brand, the endotoxin had higher affinity for the bonding agents than for the composites. There is no previous study assessing the affinity of LPS for orthodontic adhesive systems. This study revealed that LPS adheres to orthodontic adhesive systems. Therefore, additional care is recommended to orthodontic applications of these materials.

Resumo Este estudo teve como objetivo testar a hipótese de que os níveis de contaminação de Streptococcus mutans diferem de acordo com o tipo de ligadura ortodôntica. Treze pacientes foram selecionados. Cada quadrante foi submetido aleatoriamente a um dos seguintes protocolos de uso de ligadura: I) ligadura elastomérica, II) ligadura de aço trançada sobre o arco, III) ligadura de aço trançada sob o arco e IV) ligadura de aço em um padrão de “oito” sob o arco. Após sete dias, os dispositivos foram removidos e a contagem das unidades formadoras de colônia de S. mutans por mg de peso de biofilme foi determinada. Doze espécimes (n = 3) também foram processados para análise por microscopia eletrônica de varredura. Análise de variância e teste de Tukey-Kramer foram utilizados para comparações a fim de avaliar as diferenças de níveis de S. mutans entre os grupos com significância de 5%. Não houve diferença estatisticamente significante em níveis detectáveis de S. mutans entre os grupos (p = 0,294). Os resultados da microscopia eletrônica de varredura mostraram biofilmes abundantes e contaminação microbiana em todos os grupos. Em conclusão, os níveis de contaminação de S. mutans são semelhantes nas diferentes ligaduras ortodônticas.

Abstract This study aimed to test the hypothesis that Streptococcus mutans contamination levels differ according to the type of the orthodontic ligature. Thirteen patients were selected. Each quadrant was randomly subjected to one of the following ligature-use protocols: I) elastomeric chain, II) steel ligature crossed over the archwire, III) steel ligature crossed under the archwire, and IV) steel ligature in a figure-eight pattern under the archwire. After seven days, the devices were removed and the Streptococcus mutans colony-forming unit count per mg of biofilm weight was determined. Twelve specimens (n=3) were also processed for scanning electron microscopy analysis. ANOVA and Tukey-Kramer test were used for comparisons to assess S. mutans differences between groups at a 5% significance level. There was no statistical difference in detectable levels of S. mutans among the groups (p=0.294). Scanning electron microscopy results showed abundant biofilms and microbial contamination in all groups. In conclusion, S. mutans contamination levels are similar in the different orthodontic ligatures.

Resumo A mordida aberta anterior apresenta uma etiologia multifatorial causada pela interação entre hábitos de sucção e fatores genéticos. O objetivo deste estudo foi avaliar a associação entre mordida aberta anterior e polimorfismo nos genes que codificam as metaloproteinases da matriz (MMPs) e seus inibidores teciduais (TIMPs). Foram avaliadas 472 crianças que apresentvam pelo menos um hábito de sucção. As crianças foram clinicamente examinadas para avaliar a presença de mordida aberta anterior. DNA genômico foi extraído da saliva. A genotipagem dos polimorfismos selecionados em MMP2, MMP3, MMP9, TIMP1 e TIMP2 foi realizada por PCR em tempo real, usando o método de TaqMan. As frequências alélicas e genotípicas foram comparadas entre os grupos com e sem mordida aberta anterior usando o software PLINK®. Duzentas e dezenove crianças apresentavam mordida aberta anterior enquanto 253 não a apresentavam. O polimorfismo rs17576 em MMP9 estava significativamente associado com mordida aberta anterior (p=0,009). No modelo recessivo (GG versus AG+AA) o genótipo GG foi um fator protetor para mordida aberta anterior (p=0,014; OR 4,6; 95%CI 1,3- 16,2). Concluindo, o polimorfismo rs17576 (substituição de glutamina por arginina) em MMP9 está associado com mordida aberta anterior. Os resultados obtidos suportam a hipótese de que fatores genéticos estão envolvidos com a etiologia da mordida aberta anterior.

Abstract Anterior open bite (AOB) has a multifactorial etiology caused by the interaction of sucking habits and genetic factors. The aim of this study was to evaluate the association between AOB and polymorphisms in genes that encode Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). Four hundred and seventy-two children that presented at least one sucking habit were evaluated. Children were examined clinically for the presence of AOB. Genomic DNA was extracted from saliva. Genotyping of the selected polymorphisms in MMP2, MMP3, MMP9, TIMP1 and TIMP2 was carried out by real-time PCR using the TaqMan method. Allele and genotype frequencies were compared between the groups with and without AOB using the PLINK® software in a free and in a recessive model using a chi-square test. Logistic regression analysis was implemented (p≤0.05). Two hundred nineteen children had AOB while 253 did not. The polymorphism rs17576 in MMP9 was significantly associated with AOB (p=0.009). In a recessive model GG genotype was a protective factor for AOB (p=0.014; OR 4.6, 95%CI 1.3-16.2). In the logistic regression analysis, none of the genes was associated with AOB. In conclusion, the polymorphism rs17576 (glutamine for arginine substitution) in MMP9 was a protective factor for AOB.

Abstract Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM) in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC) (Fuji ORTHO LC) and a light cured composite resin (Transbond XT), and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF) on SM counts. In a parallel study design, two groups (n=14/15) were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.

RESUMO OBJETIVO: o objetivo deste estudo foi avaliar in vitro a influência do laser de CO2 sobre a resistência ao cisalhamento da colagem (RCC) no esmalte dentário, usando diferentes tipos de braquetes cerâmicos. MÉTODOS: no total, 60 superfícies de esmalte de incisivos bovinos foram obtidas e aleatoriamente divididas em dois grupos, de acordo com o braquete cerâmico utilizado: Allure (A) e Transcend (T). Cada grupo foi dividido em dois subgrupos (n = 15): L, laser (10W, 3s); C, sem laser, ou controle. Vinte e quatro horas após a colagem dos braquetes com o sistema Transbond XT, foi realizado o teste de resistência ao cisalhamento, com velocidade de 0,5 mm/min, em máquina universal de ensaios mecânicos. Após a descolagem, o Índice de Remanescente de Adesivo (IRA) foi avaliado com aumento de 10X e comparado entre os grupos. Os dados foram analisados pelo ANOVA one-way, testes de Tukey’s, Mann-Whitney’s e Kruskal-Wallis (α = 0,05). RESULTADOS: as médias da RCC em MPa foram: AL = 0,88 ± 0,84; AC = 12,22 ± 3,45; TL = 12,10 ± 5,11; TC = 17,71 ± 6,16. A análise do IRA mostrou que 73% dos corpos de prova apresentaram todo o compósito remanescente aderido à superfície do esmalte (escore 3). O grupo TC apresentou valor significativamente maior de RCC do que os outros grupos. Os corpos de prova dos grupos com laser obtiveram valores adesivos significativamente menores do que os corpos de prova dos grupos sem laser, com ambos os tipos de braquetes. CONCLUSÃO: a irradiação com laser de CO2 diminuiu os valores de RCC dos braquetes policristalinos testados, principalmente do Allure.

ABSTRACT OBJECTIVE: The aim of this study was to assess in vitro the influence of the CO2 laser and of the type of ceramic bracket on the shear bond strength (SBS) to enamel. METHODS: A total of 60 enamel test surfaces were obtained from bovine incisors and randomly assigned to two groups, according to the ceramic bracket used: Allure (A); Transcend (T). Each group was divided into 2 subgroups (n = 15): L, laser (10W, 3s); C, no laser, or control. Twenty-four hours after the bonding protocol using Transbond XT, SBS was tested at a crosshead speed of 0.5 mm/min in a universal testing machine. After debonding, the Adhesive Remnant Index (ARI) was evaluated at 10 x magnification and compared among the groups. Data were analyzed by one-way ANOVA, Tukey’s, Mann-Whitney’s and Kruskal-Wallis tests (α = 0.05). RESULTS: Mean SBS in MPa were: AL = 0.88 ± 0.84; AC = 12.22 ± 3.45; TL = 12.10 ± 5.11; TC = 17.71 ± 6.16. ARI analysis showed that 73% of the specimens presented the entire adhesive remaining on the tooth surfaces (score 3). TC group presented significantly higher SBS than the other groups. The lased specimens showed significantly lower bond strength than the non-lased groups for both tested brackets. CONCLUSION: CO2 laser irradiation decreased SBS values of the polycrystalline ceramic brackets, mainly Allure.

Resumo O objetivo desse estudo foi avaliar a associação entre os polimorfismos no gene TCN2 (rs1801198) e no gene MTRR (rs1801394) com fissura de lábio e/ou palato não sindrômica (NSFL/P) em uma população brasileira. DNA genômico foi extraído de células bucais. Os polimorfismos nos genes TCN2 (rs1801198) e MTRR (rs1801394) foram genotipados através do PCR em tempo real pelo método Taqman. O teste do qui-quadrado foi utilizado para determinar a associação entre a frequência alélica e genotípica e NSFL/P e nos subtipos (fissura de lábio, fissura de lábio com palato e fissura de palato). Oitocentos e sessenta e sete indivíduos não aparentados (401 casos com NSFL/P e 466 indivíduos sem fissura) foram avaliados. A distribuição dos genótipos dos polimorfismos de TCN2 e MTRR estavam em equilíbrio de Hardy-Weinberg. O genótipo polimórfico GG do gene TCN2 foi identificado em 16,7% do grupo com NSFL/P e em 14,1% do grupo sem fissura (p>0,05). Da mesma forma, a freqüência do genótipo GG do gene MTRR foi bastante semelhante entre o grupo com NSFL/P (15,5%) e o grupo controle (17,8%). A análise multivariada mostrou associação entre o gene MTRR e o subgrupo que apresentou tabagismo materno durante a gestação (p=0,039). Nossos resultados mostraram que não há associação entre os polimorfismos nos genes TCN2 e NSFL/P, entretanto sugerem uma associação entre MTRR e a etiologia de NSFL/P.

The aim of this study was to evaluate the association of the polymorphisms in TCN2 (rs1801198) gene and in MTRR (rs1801394) gene with nonsyndromic cleft lip and/or palate (NSCL/P) in a Brazilian population. Genomic DNA was extracted from buccal cells. The polymorphisms in TCN2 (rs1801198) and MTRR (rs1801394) genes were genotyped by carrying out real-time PCR and Taqman assay. Chi-square test was used to determine the association between genotype and allele frequencies with NSCL/P and NSCL/P subgroups (cleft lip only, cleft lip and palate, and cleft palate only). Eight hundred and sixty seven unrelated individuals (401 cases with NSCL/P and 466 individuals without cleft) were evaluated. Genotype distributions of TCN2 and MTRR polymorphisms were in Hardy-Weinberg equilibrium. The TCN2 polymorphic genotype GG was identified in 16.7% of the NSCL/P group and in 14.1% of the non-cleft group (p>0.05). Similarly, the frequency of MTRR genotype (GG) was similar in NSCL/P group (15.5%) and control group (17.8%) (p>0.05). Multivariate analysis showed an association between MTRR and the subgroup that the mother smoked during pregnancy (p=0.039). Our findings did not demonstrate an association between TCN2 polymorphisms and NSCL/P, however suggests an association between MTRR and NSCL/P etiology