Effect of fluoride on mechanical properties of NiTi and CuNiTi orthodontic archwires: an in vitro study

ABSTRACT Introduction: After debonding, white spot may appear on the area below the bracket, which is the early clinical sign of carious lesion. There is increased caries risk underneath and adjacent to orthodontic bands and brackets, which call for maximum use of caries preventive procedures using various fluoride application methods. Objective: The aim of the study was to evaluate alterations in the mechanical properties (modulus of elasticity and yield strength) in loading and unloading phases for different orthodontic archwires (nickel-titanium [NiTi] and copper-nickel-titanium [CuNiTi]) when exposed routinely to fluoride prophylactic agents for a predetermined period of time. Methods: Preformed rectangular NiTi and CuNiTi wires were immersed in fluoride solution and artificial saliva (control) for 90 minutes at 37ºC. After immersion, specimens were tested using a 3-point bend test on a universal testing machine. Results: There is a significant reduction in the unloading yield strength when the NiTi and CuNiTi wires were exposed to APF gel. Conclusion: The result suggests that use of topical fluoride agents affect the mechanical properties of the wires, leading to increase in treatment duration. Fluoride prophylactic agents must be used with caution in patients undergoing orthodontic treatment. Injudicious use of these agents may cause corrosive effects on the orthodontic wire surfaces, with alteration in their mechanical properties.

RESUMO Introdução: Após a remoção dos braquetes, manchas brancas podem aparecer na área embaixo deles, as quais são o sinal clínico inicial da lesão cariosa. Existe um maior risco de cáries embaixo e ao redor das bandas e braquetes ortodônticos, o que exige a máxima utilização de procedimentos preventivos de cárie, usando diferentes métodos com aplicação de flúor. Objetivo: O objetivo do presente estudo foi avaliar alterações nas propriedades mecânicas (módulo de elasticidade e resistência ao escoamento), nas fases de carregamento e descarregamento de diferentes fios ortodônticos (níquel-titânio [NiTi] e níquel-titânio com adição de cobre [CuNiTi]), quando expostos rotineiramente a agentes profiláticos fluoretados, utilizados durante um período de tempo predeterminado. Métodos: Os fios pré-contornados retangulares de NiTi e CuNiTi foram imersos em solução fluoretada e saliva artificial (controle) durante 90 minutos a 37°C. Após a imersão, as amostras foram testadas utilizando-se um teste de flexão em três pontos, em uma máquina universal de testes. Resultados: Houve uma redução significativa na resistência ao escoamento na fase de descarregamento quando os fios de NiTi e CuNiTi foram expostos ao gel fluoretado. Conclusão: O resultado sugere que o uso tópico de agentes fluoretados afeta as propriedades mecânicas dos fios, levando a um aumento na duração do tratamento. Os agentes profiláticos fluoretados devem ser utilizados com cautela em pacientes submetidos a tratamento ortodôntico. O uso indiscriminado desses agentes pode causar efeitos corrosivos na superfície dos fios ortodônticos e consequente alteração das suas propriedades mecânicas.

Comparative Study of Bisphenol A Release from Various Orthodontic Adhesive and Myofunctional Appliances - An In-Vitro Study.

We wanted to compare & evaluate, regularly used orthodontic materials including adhesives & myofunctional appliances for release of Bisphenol A. MethodsBisphenol - A release was assessed from two materials - orthodontic adhesive resin and heat cure acrylic resin [twin block]. Based on materials used, a total of 40 samples was assigned into two groups; Group A and Group B, each containing 20 samples. For Group A [orthodontic adhesive resin], metal brackets were bonded to 20 bicuspid teeth using adhesive resin and cured with LED light. For group B, 20 twin block appliances made from heat cured acrylic resin were used. Then, samples from both the groups were immersed in artificial saliva and then subjecting to thermal treatment from hot (60 ˚C) to cold (4 ˚C) temperatures, followed by shaking for 5 minutes. The samples were again shaken at (37 ˚C) and 1.0-mL aliquots were removed at 24 hours and 7 days after insertion. Gas chromatography / mass spectroscopy was used for the evaluation of leaching of bisphenol A from artificial saliva. ResultsSignificant results were found after 24 hours of analysis in both groups where 70 % samples from group A had bisphenol A release, whereas 80 % samples from group B had bisphenol A release. However, a non-significant result was obtained after 7 days where 20 % samples from group A had bisphenol A release whereas 60% samples from group B had bisphenol A release. The Heat cure acrylic group showed higher Bisphenol - A than that of orthodontic adhesive resin group. It was seen that the levels were lower than the reference dose which were calculated for daily consumption but were statistically significant. CoclusionsBisphenol A is considered as an endocrine disruptor. Degradation of orthodontic materials results in leaching of Bisphenol-A into oral cavity which is a clinical concern.

To Evaluate the Shear Bond Strength of Bondable Molar Tubes by Two Enamel Conditioning Techniques

Shear Bond Strength (SBS) is considered to be the main factor in the evolution of bonding. The bracket bond strength should withstand the forces during the orthodontic tooth movement. The commonly used technique by Orthodontists is to attach the brackets to the enamel surface is the acid-etch bonding technique along with 37 % phosphoric acid as etchant. With time, a new technique emerged in orthodontics which is used before bonding for the primary preparation of teeth as well as for the purpose of increasing bond strength known as Sandblasting. This study was done to compare the shear bond strength of acid etching and air abrasion technique used in orthodontic practice. MethodsA total of 100 extracted human first molar teeth were selected and segregated into 4 groups of 25 teeth. Group I: bonding without enamel preparation, Group II: using acid etching with 37 % phosphoric acid, Group III - sandblasting with 50 μ aluminium oxide, Group IV - sandblasting with 100 μ aluminium oxide. These 100 samples were then subjected to the measurement of the shear bond strength with an Instron machine and was measured in Newtons. ResultsGroup 1 showed a mean shear bond strength of 7.21 ± 0.29; for group II it was 7.77 ± 0.53; for group III it was 8.3 ± 0.3 and for group IV it was 10.04 ± 0.45. Groups 2 and 3 and groups 2 and 4 showed statistically significant difference. Shear bond strengths of both the groups 3 and 4 showed highly statistically significant difference. Conclusions100 µ aluminium oxide group showed the highest Shear Bond Strength. On inter group comparison, sandblasting with aluminium oxide was found to have better shear bond strength compared to conventional acid etching techniques.

Awareness of orthodontic treatment among school teachers in Karad Taluka

Introduction: Health is defined as a state of complete physical, mental, and social well-being. Awareness of orthodontic treatment varies in different regions. Undergoing orthodontic treatment to correct malocclusion would be very beneficial to children as it could help eliminate bullying by peers regarding facial appearance. This kind of bullying by peers could affect the child psychologically. Materials and Methods: A questionnaire survey was conducted in Karad Taluka in Maharashtra. A total of 378 subjects were selected. The schools were randomly selected. A questionnaire including general information, knowledge, and awareness of orthodontic treatment was prepared, and the teachers were given 15 min to fill it. Since it was a short period of time to gather information from other sources, the participants answered the questionnaire using their own knowledge. The purpose of this questionnaire, which consisted of 12 questions in both English and Marathi was to evaluate the level of knowledge the teachers had about orthodontic treatment. The purpose of the study and questionnaire forms were explained by the examiner. The responses of the teachers to the questions were recorded on a 2-point Likert scale {YES or NO}. Results: Simple descriptive statistics was applied to describe the study variables. A Chi-square test of independence was performed to check independence between answers and gender for each question. Conclusion: Within limits of this study, it may be concluded that knowledge of available treatments was more in males compared to females in rural areas.

Anthropometric Evaluation of Facial Dimensions in Population of Western Maharashtra

Objective The present study was carried out to evaluate an average ratio between specific soft tissue parameters of the face among the young adult population of Karad, Maharashtra. The soft tissue parameters gauged in the present study are inner canthal distance, outer canthal distance, alar base width and distance between the corners of the mouth. Rationale The average ratio of soft tissue parameters of the face can act as a guideline for effective treatment of teeth and dento facial structures as well as soft tissue outlines. Materials and Methods 1,786 young adults aged between 18 and 20 years from Karad city were initially screened, out of which 1,000 were selected on the basis of the inclusion criteria. The fronto-facial photographs of the selected subjects were captured using a digital camera. The selected facial soft tissue parameters were digitally measured, and the data were subjected to statistical analysis. Result The values of the parameters measured were marginally more in males; however, the ratio among the parameters was similar in both the sexes. The average ratio between the inner canthal distance, alar base width and distance between corners of the mouth was found to be 1:1.3:1.7, and the average ratio between the outer canthal distance, alar base width and distance between the corners of the mouth was found to be 2.3:1:1.3. Conclusion The different parts of the human face exist in certain proportions. Establishing the ratio between these parameters is important to facilitate proper diagnosis and treatment planning for the specific population.