Comparison of the mechanical properties and surface topography of as-received and as-retrieved Copper-Nickel-Titanium arch wires: An ex-vivo study.

AIM: The mechanical and surface characteristics of Copper NiTi wires following intraoral aging in an important topic. This ex-vivo study is designed to assess the three most important mechanical properties; torsional stiffness, 3-point bending and surface hardness of the as-received Copper NiTi orthodontic archwires and compare them to the retrieved ones. MATERIAL AND METHODS: In this study, 50 round CuNiTi (0.016 inch) and 50 rectangular (0.018×0.025 inch) CuNiTi orthodontic wires (American Orthodontics, Tanzo Copper Nickel Titanium, Sheboygan, WI) were tested. The groups were as follow: 25 as-received 0.016 inch round CuNiTi archwires (group 1), 25 as-retrieved 0.016 inch round CuNiTi archwires (group 2), 25 as-received 0.018×0.025 inch rectangular CuNiTi archwires (group 3), and 25 as-retrieved 0.018×0.025 inch rectangular CuNiTi archwires (group 4). The physical properties of all of the samples were examined using Vickers hardness, bending and torsional tests. The Kolmogorov-Smirnov test was applied to assess the normal distribution of data. An independent t-test was used to compare the variables between the groups. RESULTS: The results showed that the hardness does not significantly differ between the as-received and as-retrieved archwires in both 0.016 and 0.018×0.025 inch archwires (P< 0.05). The bending test of the round wires showed that the values of the activation forces in the as-received ones were significantly higher than those of the as-retrieved (P=0.00). The torsional and bending test results of rectangular wires showed that the amounts of forces exerted from the as-retrieved archwires were significantly higher than the new archwires (P=0.00). CONCLUSIONS: Round CuNiTi archwires could be retied in the succeeding visits. However, the bending activation that declines significantly should be took into consideration. On the other hand, since bending and torsion activation of CuNiTi rectangular archwires increased after intraoral use, these wires should be retied cautiously.

Effect of 8% arginine toothpaste on Streptococcus mutans in patients undergoing fixed orthodontic treatment: randomized controlled trial.

OBJECTIVE: To assess the effect of toothpaste containing 8% arginine on Streptococcus mutans (S. mutans) in dental plaque around orthodontic brackets, and to draw a comparison with a regular fluoride toothpaste. TRIAL DESIGN: A single-center, parallel-arm, triple-blind, randomized controlled trial was conducted. METHODS: The clinical trial was conducted at the Orthodontic Clinic, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. Seventy-two patients (age range: 15-30 years) who required fixed orthodontic treatment were recruited and randomly assigned to arginine and fluoride groups. Randomization was performed using RANDOM.ORG online software, and the participants were divided into two parallel groups, with a 1:1 allocation ratio. Patients were requested to brush their teeth twice daily for 30 days with an experimental toothpaste. Plaque sampling was performed at two intervals, namely at the beginning of the study (T0) and 30 days later (T1). Real-time PCR was used to assess plaque samples in terms of the number of S. mutans surrounding stainless steel brackets in orthodontic patients. A triple-blind design was employed. RESULTS: The baseline characteristics (age, sex, and the relative number of S. mutans) between the groups were similar (p>0.05). Only the arginine group showed a significant decrease in the relative number of bacteria between T0 and T1 (p=0.02). CONCLUSION: Arginine is an important prebiotic agent in maintaining healthy oral biofilms, and prevent dental caries during fixed orthodontic treatments. TRIAL REGISTRATION: The trial was registered at the Iranian Registry of Clinical Trials (IRCT20181121041713N2), https://en.irct.ir/user/trial/42409/view.

Effect of 8% arginine toothpaste on Streptococcus mutans in patients undergoing fixed orthodontic treatment: randomized controlled trial

ABSTRACT Objective: To assess the effect of toothpaste containing 8% arginine on Streptococcus mutans (S. mutans) in dental plaque around orthodontic brackets, and to draw a comparison with a regular fluoride toothpaste. Trial design: A single-center, parallel-arm, triple-blind, randomized controlled trial was conducted. Methods: The clinical trial was conducted at the Orthodontic Clinic, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran. Seventy-two patients (age range: 15-30 years) who required fixed orthodontic treatment were recruited and randomly assigned to arginine and fluoride groups. Randomization was performed using RANDOM.ORG online software, and the participants were divided into two parallel groups, with a 1:1 allocation ratio. Patients were requested to brush their teeth twice daily for 30 days with an experimental toothpaste. Plaque sampling was performed at two intervals, namely at the beginning of the study (T0) and 30 days later (T1). Real-time PCR was used to assess plaque samples in terms of the number of S. mutans surrounding stainless steel brackets in orthodontic patients. A triple-blind design was employed. Results: The baseline characteristics (age, sex, and the relative number of S. mutans) between the groups were similar (p>0.05). Only the arginine group showed a significant decrease in the relative number of bacteria between T0 and T1 (p=0.02). Conclusion: Arginine is an important prebiotic agent in maintaining healthy oral biofilms, and prevent dental caries during fixed orthodontic treatments. Trial registration: The trial was registered at the Iranian Registry of Clinical Trials (IRCT20181121041713N2), https://en.irct.ir/user/trial/42409/view.

RESUMO Objetivo: Avaliar o efeito de um dentifrício contendo arginina a 8% no Streptococcus mutans (S. mutans) da placa bacteriana ao redor de braquetes ortodônticos, e compará-lo a um dentifrício fluoretado convencional. Desenho do estudo: Foi conduzido um estudo unicêntrico, com braços paralelos, triplo-cego, controlado e randomizado. Métodos: O ensaio clínico foi conduzido na Clínica de Ortodontia da Faculdade de Odontologia da Universidade de Ciências Médicas de Shiraz, no Irã. Setenta e dois pacientes (com idades variando de 15 a 30 anos) que necessitavam de tratamento ortodôntico com aparelho fixo foram recrutados e alocados aleatoriamente nos grupos arginina ou flúor. A randomização foi feita usando o programa on-line RANDOM.ORG, e os participantes foram divididos em dois grupos paralelos, com proporção de alocação de 1:1. Solicitou-se aos pacientes que escovassem os dentes duas vezes ao dia com a pasta experimental, durante 30 dias. Amostras da placa bacteriana foram coletadas em dois intervalos: ao começo do estudo (T0) e após 30 dias (T1). Um PCR em tempo real foi usado para avaliar as amostras de placa, em termos de números de S. mutans ao redor dos braquetes de aço inoxidável nos pacientes ortodônticos. Um desenho de estudo triplo-cego foi usado. Resultados: As características iniciais (idade, sexo e quantidade relativa de S. mutans) foram semelhantes entre os grupos (p>0,05). Apenas o grupo arginina mostrou uma redução significativa na quantidade de bactérias entre T0 e T1 (p=0,02). Conclusão: A arginina é um agente prebiótico importante na manutenção de biofilmes bucais saudáveis, e previne as cáries dentárias durante o tratamento ortodôntico com aparelho fixo. Registro do ensaio: O ensaio foi registrado no Iranian Registry of Clinical Trials (IRCT20181121041713N2), https://en.irct.ir/user/trial/42409/view.