Eduardo Silveira Ferreira

SHEAR BOND STRENGTH OF METALLIC BRACKETS: INFLUENCE OF SALIVA CONTAMINATION

Objective: To evaluate the influence of saliva contamination on shear bond strength and the bond failure pattern of 3 adhesive systems (Transbond XT, AdheSE and Xeno III) on orthodontic metallic brackets bonded to human enamel. Material and Methods: Seventy-two permanent human molars were cut longitudinally in a mesiodistal direction, producing seventy-two specimens randomly divided into six groups. Each system was tested under 2 different enamel conditions: no contamination and contaminated with saliva. In T, A and X groups, the adhesive systems were applied to the enamel surface in accordance with manufacturers instructions. In TS, AS and XS groups, saliva was applied to enamel surface followed by adhesive system application. The samples were stored in distilled water at 37°C for 24 h, and then tested for shear bond strength in a universal testing machine (Emic, DL 2000) running at a crosshead speed of 1 mm/min. After bond failure, the enamel surfaces were observed under an optical microscope at 40x magnification. Results: The control and contaminated groups showed no significant difference in shear bond strength for the same adhesive system. However, shear bond strength of T group (17.03±4.91) was significantly higher than that of AS (8.58±1.73) and XS (10.39±4.06) groups (p<0.05). Regarding the bond failure pattern, TS group had significantly higher scores of no adhesive remaining on the tooth in the bonding area than other groups considering the adhesive remnant index (ARI) used to evaluate the amount of adhesive left on the enamel. Conclusion: Saliva contamination showed little influence on the 24-h shear bond strength of orthodontic brackets.

Effect of recycling protocol on mechanical strength of used mini-implants

Purpose. This study evaluated the influence of recycling process on the torsional strength of mini-implants. Materials and Methods. Two hundred mini-implants were divided into 4 groups with 50 screws equally distributed in five diameters (1.3 to 1.7 mm): control group (CG): unused mini-implants, G1: mini-implants inserted in pig iliac bone and removed, G2: same protocol of group 1 followed by sonication for cleaning and autoclave sterilization, and G3: same insertion protocol of group 1 followed by sonication for cleaning before and after sandblasting (Al2O3-90 µ) and autoclave sterilization. G2 and G3 mini-implants were weighed after recycling process to evaluate weight loss (W). All the screws were broken to determine the fracture torque (FT). The influence of recycling process on FT and W was evaluated by ANOVA, Mann-Whitney, and multiple linear regression analysis. Results. FT was not influenced by recycling protocols even when sandblasting was added. Sandblasting caused weight loss due to abrasive mechanical stripping of screw surface. Screw diameter was the only variable that affected FT. Conclusions. Torsional strengths of screws that underwent the recycling protocols were not changed. Thus, screw diameter choice can be a more critical step to avoid screw fracture than recycling decision.

RETRACTED: Selective Use of Hand and Forearm Muscles During Bone Screw Insertion: A Natural Torque Meter

PURPOSE To compare the maximum torque produced by different muscle groups and its influence on mini-implant insertion torque and fracture prevention. MATERIALS AND METHODS Eighty-seven professionals were evaluated for the maximum torque produced on a screwdriver by a combined action between the thumb and index finger (maximum digital torque [MDT]) and by the forearm supination movement (maximum brachial torque [MBT]). Ninety mini-implants distributed among 9 different diameters were fractured to determine the fracture torque (FT). The fracture resistance index (FRI) was obtained from: FRI_MDT = FT/MDT and FRI_MBT = FT/MBT. Analysis of variance and t tests were used to compare the groups. RESULTS The MDT was smaller than the MBT, and the 2 measurements were smaller in female subjects. The FT increased for each 0.1-mm increment in diameter. The FRI_MDT was greater than FRI_MBT for all diameters. An FRI_MDT greater than 1 was found when the diameter was greater than or equal to 1.5 mm. An FRI_MBT greater than 1 occurred with diameters equal to or greater than 1.7 mm for female subjects and 1.8 mm for male subjects. CONCLUSIONS The digital torque was 42% smaller than the brachial torque, and it was mechanically safer and biologically more compatible, allowing the prevention of the fracture of mini-implants with a diameter 1.5 mm or thicker owing to an insertion torque limitation at 15 N-cm.

An interview with Kee-Joon Lee

Dental Press J Orthod. 2017 July-Aug;22(4):28-33 28 How to cite this section: Lee KJ. An interview with Kee-Joon Lee. Dental Press J Orthod. 2017 July-Aug;22(4):28-33. DOI: https://doi.org/10.1590/2177-6709.22.4.028-033.int Submitted: May 05, 2017 Revised and accepted: May 18, 2017 It is a great honor to introduce and conduct the interview with Professor Kee-Joon Lee. I had the opportunity to meet Dr. Kee-Joon in Seoul, in 2015, when we agreed to cooperate in the development of research projects involving the Department of Orthodontics of Yonsei University (Seoul/South Korea) and the Department of Orthodontics of Federal University of Rio de Janeiro (Rio de Janeiro/Brazil). Dr. Lee has world-renowned expertise in biomechanics and miniscrews, which has been published in his numerous articles in the most prestigious scientific journals as well as seen on invitations to lecture in countries worldwide. Dr. Kee-Joon Lee is Professor and Chairman of the Department of Orthodontics of Yonsei University College of Dentistry. He completed the orthodontics specialty training in Yonsei University. He was a visiting scholar at the Department of Biochemistry, University of Pennsylvania School of Dental Medicine in 2002-2004 and at the Division of Plastic Surgery, the Children’s Hospital of Philadelphia in 2010-2011. He was an adjunct professor at the Department of Orthodontics, Temple University, and at the University of Pennsylvania (2010-2011). He has contributed many book chapters on biomechanics of miniscrew-driven orthodontics, non-extraction treatment in adults, up-to-date lingual orthodontic mechanics and surgery-first approached using TADs. He is the first who demonstrated the miniscrew-assisted rapid palatal expander (MARPE) for adults in AJO-DO, which was cited by many other authors. He has published many articles and case reports regarding the treatment of non-eruption, and total arch movement for hyperdivergent face in orthodontic journals including two cover issues in AJO-DO. His research fields include clinical biomechanics regarding TADs application and the suture and bone responses to orthodontic stimulus. He has served as a reviewer in major orthodontic journals, including AJO-DO, Angle Orthodontists and European Journal of Orthodontics. He has been invited to many international orthodontic conferences around the world. We were honored to receive Professor Kee-Joon Lee last year, in October, for the Meeting of Alumni Association of Graduate Course in Orthodontics of Federal University of Rio de Janeiro. It was one more of his outstanding conferences in biomechanics with miniscrews.

Má oclusão de Classe I de Angle, com ausência congênita e impacção de dentes permanentes

This article reports the orthodontic treatment of a 14 year and 6 months old patient that had a Angle Class I malocclusion with an ectopic position and impaction of the tooth 45 and congenitally absence of tooth 35. This case was treated with the extraction of the tooth 45 and space closure in the lower arch. Initial, final and post-treatment orthodontic records will be presented and discussed. This case was presented to the Brazilian Board of Orthodontics and Facial Orthopedics (BBO), representing the category 7, free choice, as part of the requirements for achieving the title of BBO diplomate.