Microbial species associated with dental caries found in saliva and in situ after use of self-ligating and conventional brackets

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.

Comparing the periodontal clinical effect between conventional and self-ligating brackets: systematic review and meta-analysis

Introduction: orthodontists constantly seek to reduce the duration of their provided treatments and the patient's time in the office. for this reason, different bracket systems are currently used in orthodontics; an example is self-ligating brackets (SLB) which are believed to offer advantages over conventional brackets (CB). objective: to evaluate and compare the clinical periodontal effect of CB and SLB through a systematic review and a meta-analysis. material and method: a search of the literature was carried out until December 2017, in the biomedical databases: PubMed, Embase, SciELO, ScienceDirect, SIGLE, LILACS, BBO, Google Scholar and the Cochrane Central Register of Controlled Trials. the selection criteria of the studies were defined as such: randomized clinical trials, up to 5 years old and that report the clinical effects (probing depth, bleeding on probing, gingival index and plaque index) from the use of CB and SLB. the risk of study bias was analyzed through the Cochrane Handbook of systematic reviews of interventions. results: the search strategy resulted in 12 articles, eight of which reported no difference in the reduction in probing depth, bleeding on probing, gingival index and plaque index (p>0.05) between CB and SLB. conclusion: the literature reviewed suggests that there are no differences in the periodontal clinical effect among patients who received orthodontic treatment with CB or SLB.

Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

RESUMO Introdução: a deposição de filme de polímero a plasma foi criada para modificar as propriedades de superfície dos braquetes ortodônticos metálicos, com o intuito de inibir a adesão bacteriana. Métodos: filmes finos de polímero de hexametildisiloxano (HMDSO) foram depositados em braquetes ortodônticos de aço inoxidável convencionais (n = 10) e autoligáveis (n = 10), utilizando a técnica de radiofrequência PECVD (Plasma-Enhanced Chemical Vapor Deposition). As amostras foram divididas em dois grupos, de acordo com o tipo de braquete, e dois subgrupos após o tratamento de superfície. A microscopia eletrônica de varredura (MEV) foi realizada para avaliar a presença de adesão bacteriana sobre as superfícies das amostras (região de ranhura horizontal e aletas) e a integridade da camada de filme. A Interferometria Confocal (CI) avaliou a rugosidade, e a molhabilidade superficial foi avaliada por goniometria. Para análise de adesão bacteriana, as amostras foram expostas durante 72 horas a uma solução de Streptococcus mutans, para formação de biofilme. Os valores obtidos para a rugosidade da superfície foram analisados pelo teste de Mann-Whitney, enquanto a adesão do biofilme foi avaliada pelos testes de Kruskal-Wallis e SNK. Resultados: observaram-se diferenças estatisticamente significativas (p <0,05) para a rugosidade superficial e redução da adesão bacteriana em braquetes convencionais após o tratamento da superfície, e entre braquetes convencionais e autoligáveis. Não foram observadas diferenças estatísticas significativas entre os grupos autoligáveis (p> 0,05). Conclusão: a deposição de polímero a plasma só foi efetiva na redução da rugosidade superficial e adesão bacteriana em braquetes convencionais. Observou-se, também, que os braquetes convencionais apresentaram menor adesão ao biofilme do que os braquetes autoligáveis, apesar da ausência de filme.

Influence of resin-modified glass ionomer and topical fluoride on levels of Streptococcus mutans in saliva and biofilm adjacent to metallic brackets

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.

Evaluación de la portación de cándida spp en pinzas ortodóncicas post utilización / Evaluation of candida spp carriage on orthodontic pliers, after using them

Objetivo: evaluar el nivel de contaminación por Candida spp, post uso del instrumental de ortodoncia que se utiliza intrabucalmente en pacientesColombianos y Argentinos. Materiales y métodos: Se incluyeron pacientesentre 16 y 65 años, de ambos sexos, con armado de brackets superior e inferior. Criterios de Exclusión: pacientes con brackets de autoligado, con enfermedades autoinmunes, con enfermedades sistémicas con manifestaciones en el periodonto, pacientes fumadores, menores de 16 años y con armado de brackets en un solo maxilar. Se analizaron los alicates de corte distal Hu Friedy luego de ser utilizados para seccionar el arco por distal del último tubo presente enboca. Se estudiaron 80 pacientes agrupados en: Grupo A 40 pacientesColombianos, Grupo B 40 pacientes argentinos. Se realizó una primer tomaintrabucal con un hisopo estéril y se llevó a un tubo con medio de Stuart. Se cortaron las 4 secciones distales de los arcos en boca tardando al menos 1 minuto. Con un segundo hisopo estéril se frota toda la superficie del alicate post uso y se llevaron a otro tubo. Se sembraron en Chromagar Candida y se realizaron pruebas microbiológicas convencionales. Resultados: Las pinzas estériles aparecen contaminadas post corte distal delos alambres en el 95% de los casos en ambos países. Hubo diferencia entrelos pacientes colombianos y los argentinos respecto a las especies, ya que enlos primeros la especie con mayor prevalencia fue Candida tropicalis tanto en lapinza como en la cavidad bucal, mientras que en los argentinos fue Candidaalbicans. Conclusión: las pinzas de ortodoncias se contaminan con Candidaspp post utilización en boca y son un fómite a partir del cual puede generarsediseminación sistémica así como infección cruzada.

Effect of silver nanoparticles on the physicochemical and antimicrobial properties of an orthodontic adhesive

ABSTRACT Orthodontic treatment with fixed brackets plays a major role on the formation of white spot lesions. Objective This study aimed to incorporate silver nanoparticle solutions (AgNP) in an orthodontic adhesive and evaluate its physicochemical and antimicrobial properties. Material and Methods Silver nanoparticle solutions were added to a commercial adhesive in different concentrations (w/w): 0%, 0.11%, 0.18%, and 0.33%. Shear bond strength (SBS) test was performed after bonding metal brackets to enamel. Raman spectroscopy was used to analyze in situ the degree of conversion (DC) of the adhesive layer. The surface free energy (SFE) was evaluated after the measurement of contact angles. Growth inhibition of Streptococcus mutans in liquid and solid media was determined by colony-forming unit count and inhibition halo, respectively. One-way ANOVA was performed for SBS, DC, SFE, and growth inhibition. Results The incorporation of AgNP solution decreased the SBS (p<0.001) and DC in situ (p<0.001) values. SFE decreased after addition of 0.18% and 0.33% AgNP. Growth inhibition of S. mutans in liquid media was obtained after silver addition (p<0.05). Conclusions The addition of AgNP solutions to Transbond™ XT adhesive primer inhibited S. mutans growth. SBS, DC, and SFE values decreased after incorporation up to 0.33% AgNP solution without compromising the chemical and physical properties of the adhesive.

Does the bracket composition material influence initial biofilm formation.

Context: Orthodontic treatment has been reported to contribute to the development and accumulation of dental biofilm, which is commonly found on bracket and adjacent surfaces. Aims: The aim of this work is to test the hypothesis if there are differences in dental biofilm formation on the surface of orthodontic brackets according to the type of composition material. Subjects and Methods: Three bracket types (metallic, composite, and ceramic) had been evaluated. Subjects wore acrylic palatal orthodontic appliances, containing 6 brackets each, for two 3‑day cycles. On the end of first cycle, the amount of dental biofilm formed on the samples was extracted using 1.0‑M NaOH and analyzed by spectrophotometry for quantification. An additional cycle was carried out to verify the dental biofilm formation using scanning electronic microscope analysis. Statistical Analysis Used: Three‑way ANOVA was used to analyze the difference among the materials (metallic, ceramic and composite) concerning the dental biofilm absorbance spectrum. Multiple comparisons were made using the Tukey’s test (α =0.05). Results: Composite brackets showed greater values concerning biofilm formation, when compared with the metallic and ceramic ones, both of which presented similar scores. The hypothesis is accepted. There are differences on the biofilm formation according to the type of material. Conclusions: The in situ model tested was found to be effective in evaluating the accumulation and development of biofilm on orthodontic brackets. In the quantitative analysis, composite brackets showed greater biofilm adhesion values while metallic and ceramic presented similar biofilm absorbance spectrum.

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 ...

Quantitative analysis of S. mutans and S. sobrinus cultivated independently and adhered to polished orthodontic composite resins

In Orthodontics, fixed appliances placed in the oral cavity are colonized by microorganisms. OBJECTIVE: The purpose of this study was to quantitatively determine the independent bacterial colonization of S. mutans and S. sobrinus in orthodontic composite resins. MATERIAL AND METHODS: Seven orthodontic composite adhesives for bonding brackets were selected and classified into 14 groups; (GIm, GIs) Enlight, (GIIm, GIIs) Grengloo, (GIIIm, GIIIs) Kurasper F, (GIVm, GIVs) BeautyOrtho Bond, (GVm, GVs) Transbond CC, (GVIm, GVIs) Turbo Bond II, (GVIIm, GVIIs) Blugloo. 60 blocks of 4x4x1 mm of each orthodontic composite resin were made (total 420 blocks), and gently polished with sand-paper and ultrasonically cleaned. S. mutans and S. sobrinus were independently cultivated. For the quantitative analysis, a radioactive marker was used to codify the bacteria (³H) adhered to the surface of the materials. The blocks were submerged in a solution with microorganisms previously radiolabeled and separated (210 blocks for S. mutans and 210 blocks for S. sobrinus) for 2 hours at 37ºC. Next, the blocks were placed in a combustion system, to capture the residues and measure the radiation. The statistical analysis was calculated with the ANOVA test (Sheffè post-hoc). RESULTS: Significant differences of bacterial adhesion were found amongst the groups. In the GIm and GIs the significant lowest scores for both microorganisms were shown; in contrast, the values of GVII for both bacteria were significantly the highest. CONCLUSIONS: This study showed that the orthodontic composite resin evaluated in the GIm and GIs, obtained the lowest adherence of S. mutans and S. sobrinus, which may reduce the enamel demineralization and the risk of white spot lesion formation.

Influence of lingual bracket position on microbial and periodontal parameters in vivo

OBJECTIVE: Lingual orthodontics is becoming more popular in dental practice. The purpose of the present investigation was to compare plaque formation on teeth bonded with the same bracket onto buccal or lingual surface, with non-bonded control teeth, via an in vivo growth experiment over a 30-day period. MATERIAL AND METHODS: A randomized controlled trial with split-mouth design was set up enrolling 20 dental students. Within each subject sites with buccal and lingual brackets and control sites were followed. Clinical periodontal parameters (periodontal pocket depth: PPD; bleeding on probing: BOP) were recorded at baseline and on days 1, 7 and 30. Microbiological samples were taken from the brackets and the teeth on days 1, 7 and 30 to detect colony-forming units (CFU). Total CFU, streptococci CFU and anaerobe CFU were measured. RESULTS: No significant differences (P>0.05) were found between buccal and lingual brackets in terms of clinical periodontal parameters and microbiological values. Conclusion: Bracket position does not have significant impact on bacterial load and on periodontal parameters.

Avaliação da aderência de biofilme bacteriano em bráquetes metálicos, plásticos e cerâmicos / Evaluation of the adhesion of bacterial biofilm in metallic, plastic and ceramic brackets

As diferentes superfícies dos acessórios ortodônticos podem demonstrar impacto microbiológico distinto quando expostos à cavidade bucal. Esse trabalho discute os aspectos relacionados à aderência de biofilme em bráquetes de diferentes composições estruturais e com os tipos de amarração normalmente empregados na rotina clínica. Quarenta voluntários tiveram amostras salivares colhidas para avaliação dos microorganismos presentes e 15 destes foram selecionados dentro de faixas específicas de padrão de colonização bacteriana. Foram utilizados 6 grupos distintos de bráquetes afixados em duplicata a placas de acetato individualizadas, que foram utilizadas por um período de vinte e quatro horas para permitir a formação de biofilme. Os dispositivos foram removidos e submetidos a meios de cultura microbiana específicos para crescimento de Streptococcos mutans e Lactobacillus sp. e para avaliação do crescimento de microrganismos totais. Os resultados foram expressos com relação ao número de unidades formadoras de colônia por miligrama de placa aderida (UFC/mg) e posteriormente submetidos ao teste de Friedman para comparação dos grupos. As eventuais diferenças foram avaliadas pelo teste de Wilcoxon, com correção de Bonferroni, com poder de 80% e nível de significância de 5%. Na análise de microorganismos totais, não houve diferença estatística detectável que pudesse estabelecer diferenças entre os bráquetes avaliados. Para Streptococcos mutans, foi possível observar diferença estatística significativa (p=0,032) e os dados obtidos indicaram menor tendência de aderência microbiana aos bráquetes cerâmicos dos três tipos avaliados (monocristalino, policristalino e autoligável). Não houve crescimento suficiente de colônias de Lactobacillus sp. que possibilitasse a devida comparação entre os grupos.

Different surfaces of orthodontic accessories can demonstrate distinct microbiological impact when exposed to the oral cavity. This paper discusses aspects related to the biofilm adherence in brackets of different compositions and structural types and with the most commonly used ligation methods. Forty volunteers had salivary samples taken for microbiological assessment and 15 of them were selected within specific patterns of bacterial colonization. We used six different duplicate sets of brackets affixed to individual acetate plates which were used for a twenty-four hours period to allow biofilm formation. The devices were removed and placed in specific microbial culture media for growth of total bacteria, Streptococcos mutans and Lactobacillus sp. Results were expressed as the number of colony forming units per miligram of plaque attached (CFU/mg) and then submitted to the Friedman test to compare groups. Differences were evaluated using the Wilcoxon test with Bonferroni correction, with 80% power and significance level of 5%. In the analysis of total bacteria, there was no detectable statistical difference that could make distinctions between the brackets evaluated. To Streptococcos mutans, we observed a statistically significant difference (p=0,032) and the data obtained showed a lower trend of microbiological adherence to the three types of ceramic brackets tested (monocrystalline, polycristalline and self-ligating). There was not enough growth of Lactobacillus sp. colonies that would allow proper comparison between groups.

Streptococcus mutans counts in plaque adjacent to orthodontic brackets bonded with resin-modified glass ionomer cement or resin-based composite

This study investigated the number of Streptococcus mutans CFU (colony forming units) in the saliva and plaque adjacent to orthodontic brackets bonded with a glass ionomer cement - GIC (Fuji Ortho) or a resin-based composite - RC (Concise). Twenty male and female patients, aged 12 to 20 years, participated in the study. Saliva was collected before and after placement of appliances. Plaque was collected from areas adjacent to brackets and saliva was again collected on the 15th, 30th, and 45th day after placement. On the 30th day, 0.4 percent stannous fluoride gel was applied for 4 minutes. No significant modification in the number of Streptococcus mutans CFU in saliva was observed after placement of the fixed orthodontic appliances. On the 15th day, the percentage of Streptococcus mutans CFU in plaque was statistically lower in sites adjacent to GIC-bonded brackets (mean = 0.365) than in those adjacent to RC-bonded brackets (mean = 0.935). No evidence was found of a contribution of GIC to the reduction of CFU in plaque after the 15th day. Topical application of stannous fluoride gel on the 30th day reduced the number of CFU in saliva, but not in plaque. This study suggests that the antimicrobial activity of GIC occurs only in the initial phase and is not responsible for a long-term anticariogenic property.

[Effect of mixed chlorhexidine fluoride gel made in Iran on the level of Mutans Streptococci around orthodontic brackets]

Patients with fixed orthodontic appliances often experience an increase in the rate of dental caries. Appling chlorhexidine and fluoride is known to be an effective method to solve this problem since Mutans Streptococci is described as the most important bacteria related to the etiology of dental caries. The aim of this study was to evaluate clinically the application of a chlorhexidine-fluoride gel made in Iran on the level of Mutans Streptococci in plaque adjacent to bonded orthodontic brackets. In this double blind clinical trial 37 patients were selected. The patients were divided into 2 groups: those treated with chlorhexidine-fluoride gel five times with one week interval [group A] and those treated with placebo gel [group B]. The level of Mutans Streptococci in the plaque of canine and second premolar of Maxilla before and after treatment was evaluated and compared by Wilcoxon Signed Rank test. The range of changes in group A was compared with group B by Mann-whitney test. Statistical analysis showed a significant difference between baseline and final colony count results in group A [P<0.0001] but no significant difference in group B and also Mann-Whitney test showed a significant difference between the 2 groups [P<0.0001]. Chlorhexidine-fluoride significantly decreased the level of Mutans Streptococci in plaque around the orthodontic brackets

Avaliaçäo das propriedades anticariogênicas do cimento de ionômero de vidro utilizado na fixaçäo de braquetes ortodônticos: estudo in vivo / Anticaries properties evaluation of glass ionomer cement used to orthodontic brackets retained: in vivo study

A proposta deste trabalho foi avaliar clinicamente se a quantidade de flúor liberada pelo cimento de ionômero de vidro utilizado na fixaçäo de braquetes ortodônticos, bem como a capacidade de reincorporaçäo deste íon após tratamento com agentes fluoretados e sua posterior liberaçäo, ocorre em concentraçöes capazes de exercer efeito cariostático local, nas áreas mais vulneráveis à ocorrência de lesöes de mancha branca durante a terapia ortodôntica. O grupo estudado consistiu de 20 adolescentes que foram divididos aleatoriamente em dois grupos: "F" - braquetes fixados com o cimento de ionômero de vidro Fuji Ortho LC (GC), e "C" a fixaçäo foi realizada com a resina composta Concise (3M). Trinta dias após, os dentes foram extraídos, e as análises de microdureza realizadas em secçäo longitudinal em microdurômetro com penetrador tipo Knoop. Para a avaliaçäo da concentraçäo de flúor na placa e contagem de bactérias cariogênicas, os braquetes foram retidos com resina ou ionômero de vidro ao acaso, em quadrantes opostos na maxila e mandíbula...