HIPERSENSIBILIDADE AO NÍQUEL E O APARELHO ORTODÔNTICO: ASPECTOS BIOLÓGICOS E CLÍNICOS

O níquel é um elemento responsável por até 17% dos casos de hipersensibilidade em pacientes sob tratamento ortodôntico. Apesar de ser uma preocupação recorrente, não há um consenso sobre a influência das taxas de níquel, liberadas dos aparelhos ao longo do tratamento ortodôntico, e da resposta imune inflamatória capazes de causar reações alérgicas ao paciente. O objetivo do presente estudo é apresentar uma revisão da literatura sobre os aspectos biológicos e clínicos envolvidos nas reações de hipersensibilidade ao níquel durante o tratamento ortodôntico. A coleta de dados ocorreu por meio de busca bibliográfica, nas seguintes bases de dados: Pubmed, Periódicos Capes, BVS e SciELO, utilizando os descritores “Ortodontia corretiva”, “Hipersensibilidade tardia”, e “Níquel”.  Foram selecionados 128 trabalhos publicados entre 1929 a 2019. Considerando que a utilização de dispositivos metálicos é muito frequente dentro da Ortodontia, os autores abordam quais são as implicações do uso de aparelhos com níquel na prática clínica do ortodontista. Em seguida, apresentam um dos principais problemas causados pelo íon níquel: a hipersensibilidade. Por fim, são discutidos os aspectos epidemiológicos e fatores de risco da doença, como ela se desenvolve, como se manifesta, através dos sinais e sintomas, nos indivíduos alérgicos e como é realizado o diagnóstico e o melhor tratamento para as reações. Os resultados do presente estudo podem ajudar a desenvolver estratégias eficientes e seguras para a prevenção e o tratamento dessa condição, além de contribuir para uma conduta adequada durante a terapia ortodôntica dos indivíduos

Dentoskeletal and soft tissue changes in class II subdivision treatment with asymmetric extraction protocols

Abstract Background This study cephalometrically compared the dentoskeletal and soft tissue changes consequent to one and three-premolar extraction protocols of class II subdivision malocclusion treatment. Methods A sample of 126 lateral cephalometric radiographs from 63 patients was selected and divided into two groups. Group 1 consisted of 31 type 1 class II subdivision malocclusion patients treated with asymmetric extractions of two maxillary premolars and one mandibular premolar on the class I side, with an initial mean age of 13.58 years. Group 2 consisted of 32 type 2 class II subdivision malocclusion patients treated with asymmetric extraction of one maxillary first premolar on the class II side, with an initial mean age of 13.98 years. t test was used for intergroup comparison at the pre- and posttreatment stages and to compare the treatment changes. Results Group 1 had greater maxillomandibular sagittal discrepancy reduction and greater maxillary first molar extrusion. Group 2 had mandibular incisor labial inclination and protrusion, and group 1 had mandibular incisor lingual inclination and retraction. Maxillary molar asymmetry increased in group 2, while mandibular molar asymmetry increased in group 1. Conclusions The treatment changes produced by these two class II subdivision protocols are different to adequately satisfy the different needs for types 1 and 2 class II subdivision malocclusions

Radiographic evaluation of orthodontic treatment by means of four different cephalometric superimposition methods

INTRODUCTION: Despite discussion on the merit of various cephalometric superimposition methods, there remains a need to assess which one can be used in daily practice with reasonably accuracy and less working time. OBJECTIVE: The aim of this study was to investigate four methods of cephalometric superimposition by means of assessing the longitudinal changes in craniofacial morphology caused by growth and response of adolescents with Class I malocclusion to orthodontic treatment involving first premolar extraction. METHODS: Pretreatment (T1) and post-treatment (T2) standardized lateral cephalometric radiographs of 31 adolescents (20 females and 11 males), with Angle Class I malocclusion and indication of premolar extraction, participated in this study. Radiographs were digitized, traced and had structures identified by means of a cephalometric software. Four superimposition methods were used: Bj&#246;rk structural method, Steiner/Tweed SN line, Ricketts N-Ba line at N-point and Ricketts N-Ba line at CC-point. Positional changes were quantified by horizontal and vertical linear changes in the following cephalometric landmarks: anterior/posterior nasal spine (ANS and PNS), gnathion (Gn), Gonion (Go), Pogonion (Pog), A-point and B-point. Differences between T1 and T2 in horizontal and vertical positional changes for all superimposition methods were assessed by one-way analysis of variance (ANOVA) and Bonferroni correction (p < 0.05). RESULTS: There were no statistically significant differences among the cephalometric superimposition methods or when patients' sex was considered. CONCLUSION: Bj&#246;rk structural method, Steiner/Tweed SN line, Ricketts N-Ba line at N-point and Ricketts N-Ba line at CC-point methods were reliable and presented similar precision when the overall facial changes due to active growth and/or orthodontic treatment were examined

Influence of ceramic surface treatment on shear bond strength of ceramic brackets

Objective: To compare four different surface treatment methods and determine which produces adequate bond strength between ceramic brackets and facets of porcelain (feldspathic), and evaluate the Adhesive Remnant Index (ARI) scores. Materials and Methods: Ten facets of porcelain specimens with glazed surfaces were used for each group. The specimens were randomly assigned to one of the following treatment conditions of the porcelain surface: (1) no surface treatment (control group), (2) fine diamond bur + orthophosphoric acid gel 37%, (3) hydrofluoric acid (HFL) 10%, and (4) HFL 10% + silane. Ceramic brackets were bonded with the adhesive cement Transbond XT. The shear bond strength values were measured on a universal testing machine at a crosshead speed of 0.5 mm/min. Results: There was a significant difference (P<0.05) between the control group and all other groups. There was no significant difference (P<0.05) between treated porcelain surface with diamond bur + orthophosphoric acid gel 37% (4.8 MPa) and HFL 10% (6.1 MPa), but the group treated with HFL 10% had clinically acceptable bond strength values. The group treated with HFL 10% + silane (17.5 MPa) resulted in a statistically significant higher tensile bond strength (P<0.05). In group 4, 20% of the porcelain facets displayed damage. Conclusion: Etching of the surface with HFL increased the bond strength values. Silane application was recommended to bond a ceramic bracket to the porcelain surface in order to achieve bond strengths that are clinically acceptable

Evaluation of cytotoxicity and corrosion resistance of orthodontic mini-implants

ABSTRACT Objective: To evaluate and compare in vitro cytotoxicity and corrosion resistance of mini-implants from three different commercial brands used for orthodontic anchorage. Methods: Six mini-implants (Conexão(tm), Neodent(tm) and SIN(tm)) were separately immersed in artificial saliva (pH 6.76) for 30 and 60 days. The cytotoxicity of the corrosion extracts was assessed in L929 cell cultures using the violet crystal and MTT assays, as well as cell morphology under light microscopy. Metal surface characteristics before and after immersion in artificial saliva were assessed by means of scanning electron microscopy (SEM). The samples underwent atomic absorption spectrophotometry to determine the concentrations of aluminum and vanadium ions, constituent elements of the alloy that present potential toxicity. For statistical analysis, one-way ANOVA/Bonferroni tests were used for comparisons among groups with p < 0.05 considered significant. Statistical analysis was carried out with Graph Pad PRISM software Version 4.0. Results: No changes in cell viability or morphology were observed. Mini-implants SEM images revealed smooth surfaces with no obvious traces of corrosion. The extracts assessed by means of atomic absorption spectrophotometry presented concentrations of aluminum and vanadium ions below 1.0 µg/mL and 0.5 µg/mL, respectively. Conclusion: Orthodontic mini-implants manufactured by Conexão(tm), Neodent(tm) and SIN(tm) present high corrosion resistance and are not cytotoxic

Utilização de documentação ortodôntica na identificação humana

OBJETIVO: o objetivo deste trabalho é relatar um caso pericial onde um indivíduo encontrado carbonizado foi identificado utilizando-se as informações presentes na sua documentação ortodôntica. MÉTODOS: um indivíduo do sexo masculino foi encontrado carbonizado no interior de um automóvel. Após a realização dos exames periciais no local, exames necroscópicos e radiográficos no Instituto Médico-Legal, identificou-se que a vítima utilizava aparelho ortodôntico fixo, possuía dentes supranumerários nas quatro hemiarcadas, terceiros molares semi-inclusos e restaurações de amálgama em determinadas faces de diversos dentes. Como os tecidos moles do indivíduo apresentavam-se bastante destruídos, uma identificação pela análise das impressões digitais tornou-se inviável. Após a entrega da documentação ortodôntica pela família, foi feita a análise do prontuário clínico, radiografias, fotografias intra e extrabucais e modelos de gesso - confrontando-se essas informações com as obtidas anteriormente. RESULTADOS E CONCLUSÕES: o confronto odontolegal revelou 20 pontos concordantes do exame necroscópico e da documentação ortodôntica, permitindo a determinação de uma correlação positiva entre o cadáver examinado e a identidade da pessoa desaparecida, tornando-se desnecessária a realização de outros exames para a identificação da vítima (exame de DNA)

Use of orthodontic records in human identification

OBJECTIVE: This study describes a forensic case of incinerated remains of a man that were identified using information found in his orthodontic records. METHODS: Incinerated remains of a man were found inside a car. After forensic crime scene investigation and postmortem and radiographic exams in the Forensic Department, forensic experts found that the victim had a fixed orthodontic appliance, supernumerary teeth in all quadrants, partially erupted third molars and amalgam restorations in some surfaces of several teeth. As the individual's soft tissues were substantially destroyed, identification using fingerprints was not the ideal choice. After orthodontic records were handed in by the family, his clinical chart, radiographs, intra- and extraoral photographs and impressions were analyzed, and these data were compared with previously collected information. RESULTS AND CONCLUSIONS: Forensic dentistry examination revealed 20 concordant points in specimen examination and orthodontic records, which enabled the establishment of a positive correlation between the cadaver under examination and the missing person and eliminated the need for further analyses (DNA tests) to identify the victim.OBJETIVO: o objetivo deste trabalho é relatar um caso pericial onde um indivíduo encontrado carbonizado foi identificado utilizando-se as informações presentes na sua documentação ortodôntica. MÉTODOS: um indivíduo do sexo masculino foi encontrado carbonizado no interior de um automóvel. Após a realização dos exames periciais no local, exames necroscópicos e radiográficos no Instituto Médico-Legal, identificou-se que a vítima utilizava aparelho ortodôntico fixo, possuía dentes supranumerários nas quatro hemiarcadas, terceiros molares semi-inclusos e restaurações de amálgama em determinadas faces de diversos dentes. Como os tecidos moles do indivíduo apresentavam-se bastante destruídos, uma identificação pela análise das impressões digitais tornou-se inviável. Após a entrega da documentação ortodôntica pela família, foi feita a análise do prontuário clínico, radiografias, fotografias intra e extrabucais e modelos de gesso - confrontando-se essas informações com as obtidas anteriormente. RESULTADOS E CONCLUSÕES: o confronto odontolegal revelou 20 pontos concordantes do exame necroscópico e da documentação ortodôntica, permitindo a determinação de uma correlação positiva entre o cadáver examinado e a identidade da pessoa desaparecida, tornando-se desnecessária a realização de outros exames para a identificação da vítima (exame de DNA).525