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

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.

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.

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.

Invitro Study of the Effect of Different Samples of Water Used for Washing the Etchant on Bracket Bond Strength.

BACKGROUND: Bonding is a very important step in the orthodontic treatment planning. Effective bonding enhances the treatment by reducing the bond failure and thereby reducing the treatment duration and also increases efficiency in orthodontic mechanics. The success of the bonded brackets is negatively affected by contamination with oral fluids such as blood and saliva. AIM: The aim of the present study was to evaluate the effect of hardness of water used in removing the etchant on the bracket bond strength. MATERIALS AND METHODS: Seventy five extracted premolars were divided in three groups of 25 each. The teeth in all the three groups were etched with 35% phosphoric acid. The etchant in each of the group I, II and III was removed using distilled water (soft), corporation water (moderately hard) and hard water respectively. Stainless steel brackets were attached using light cure bonding agent (transbond XT, 3M UNITEK) and cured for 10sec with a light cure unit. The shear bond strength was evaluated by mechanical testing machine. Statistically significant differences were defined for p < 0.05. RESULT: The results showed significant increase in bond strength in samples where in soft water was used for cleaning the etchant on the bonding surface. CONCLUSION: Hardness of water used for washing the etchant affects the bracket bond strength. Shear bond strength of soft water is significantly increased compared to moderately hard and very hard water.

Effect of fluoride prophylactic agents on the surface topography of NiTi and CuNiTi wires.

AIM: The aim of this study was to see the effect of topical fluoride on surface texture on nickel-titanium and copper-nickel-titanium orthodontic archwires. MATERIALS AND METHODS: Preformed rectangular NiTi and CuNiTi wires were immersed in in fluoride solution and artificial saliva (control) for 90 minutes at 37°C. after immersion optical microscope was used to see the fluoride effect on the wire topography. RESULTS: The acidulated fluoride agents appeared to cause greater corrosive effects as compared to the neutral fluoride agents. CONCLUSION: The result suggest that using topical fluoride agents leads to corrosion of surface topography indirectly affecting the mechanical properties of the wire that will lead to prolonged orthodontic treatment. CLINICAL SIGNIFICANCE: The use of topical fluoride agents has to be limited in patients with prolonged orthodontic treatment as it causes the corrosion of the NiTi and CuNiTi wires.

To determine the prevalence rate of malocclusion among 12 to 14-year-old schoolchildren of urban Indian population (Bagalkot).

AIM: To determine the prevalence rates of different occlusal characteristics of permanent dentition in 12 to 14 years old children in Bagalkot city and to determine the differences in occlusal characteristics in the same children by age and sex. MATERIALS AND METHODS: A total of 1000 school going children between the age group of 12 to 14 years were selected in the study from Bagalkot city of India. All the occlusal parameters, such as molar relation, canine relation, overjet, overbite and crowding and spacing were recorded in a record sheet. The gender and sex difference was evaluated using Chi-square test. RESULTS: According to the classification of Angle, the prevalence of class I, II and III malocclusions was 17.8, 30.1 and 1.6%, respectively. Ideal occlusion was 3.2% where as normal occlusion was 46.8%. An overjet of at least 4 mm or more was present in 15.2 and 7.2% had a reverse overjet. A total of 9.2 had an increased overbite and 10.6% had open bite. CONCLUSION: Highly significant (p < 0.001) age differences were found for overjet, overbite and highly significant (p < 0.001) gender differences were found for crowding and spacing. CLINICAL SIGNIFICANCE: The study gives the prevalence of malocclusion amongst 12 to 14 years old in urban Indian population. The data can be used for may research projects and gives us a better understanding of malocclusion in urban Indian population.