New methodology for evaluating osteoclastic activity induced by orthodontic load

Orthodontic tooth movement (OTM) is a dynamic process of bone modeling involving osteoclast-driven resorption on the compression side. Consequently, to estimate the influence of various situations on tooth movement, experimental studies need to analyze this cell. Objectives The aim of this study was to test and validate a new method for evaluating osteoclastic activity stimulated by mechanical loading based on the fractal analysis of the periodontal ligament (PDL)-bone interface. Material and Methods The mandibular right first molars of 14 rabbits were tipped mesially by a coil spring exerting a constant force of 85 cN. To evaluate the actual influence of osteoclasts on fractal dimension of bone surface, alendronate (3 mg/Kg) was injected weekly in seven of those rabbits. After 21 days, the animals were killed and their jaws were processed for histological evaluation. Osteoclast counts and fractal analysis (by the box counting method) of the PDL-bone interface were performed in histological sections of the right and left sides of the mandible. Results An increase in the number of osteoclasts and in fractal dimension after OTM only happened when alendronate was not administered. Strong correlation was found between the number of osteoclasts and fractal dimension. Conclusions Our results suggest that osteoclastic activity leads to an increase in bone surface irregularity, which can be quantified by its fractal dimension. This makes fractal analysis by the box counting method a potential tool for the assessment of osteoclastic activity on bone surfaces in microscopic examination. .

Influence of exogenous pigmentation on the optical properties of orthodontic elastic ligatures

OBJECTIVES: The aim of this study was to assess the optical properties of orthodontic elastic ligatures under the influence of exogenous pigments contained in the daily diet. MATERIAL AND METHODS: For the analysis, colorless (clear) elastic segments (ORTHO Organizers, lot 660625A10) were used as received from the manufacturer, and were divided into 8 groups of 3 segments each. Each group was immersed in 200 mL of a solution containing a determined substance, as follows: distilled water (control group), Coca-Cola®, Pomarola brand tomato sauce (Cica®), açai, Jasmine® brand green tea, Royal Blend® black tea brand, Pilão® brand coffee and Palmares® wine brand. All test specimens were immersed in the solutions and kept in an appropriate receptacle for 7 days at 37°C14. After the staining session, the test specimens were washed with distilled water in an ultrasonic vat for 5 min and dried with paper tissues6. The portable digital spectrophotometer Vita Easyshade Compact was used to assess if there was color variation of the test specimens. This variation was quantified and qualified at the initial time (T0) and after staining (T1). RESULTS: These results were analyzed statistically using the software SPSS version 18.0. The Shapiro-Wilk test of normality was applied followed by the one-way analysis of variance and the Tukey's post hoc test. The level of significance adopted was 5%. CONCLUSIONS: From the substances evaluated in this study, those with higher staining potential on esthetic elastic ligatures were black tea, coffee and wine, respectively. Knowing this information, the dentist may advise their patients to avoid certain foods because of elastic staining may occur thus decreasing the aesthetics of the material.

Liberação de flúor dos compósitos Superbond® e Ultrabond®: estudo in vitro / Release of fluoride composites Superbond® and Ultrabond®: study in vitro

O objetivo do presente trabalho foi verificar a hipótese que não há diferença no desempenho de compósitos ortodônticos entre si quanto à liberaçãode flúor. Foram analisados dois compósitos ortodônticos: Grupo SB (Superbond, OrthoSource) e Grupo UB (Ultrabond, Aditek) e um cimento de ionômero de vidro (CIV) convencional ortodôntico: Grupo S (Sumo, OrthoSource), como controle. A liberação de flúor foi medida durante 28 dias (1h, 24h, 1, 3, 7, 14, 21 e 28 dias), através de eletrodo íon seletivo conectado. Houve diferença estatística entre os grupos SB e UB com o grupo S em todos os tempos avaliados (p < 0.05). Pode-se concluir com a realização desse trabalho que os compósitos Superbond e Ultrabond apresentaram um desempenho semelhante entre si, porém pouco expressiva comparado ao CIV.

Biocompatibility of orthodontic adhesives in rat subcutaneous tissue

ABSTRACT OBJECTIVE: The objective of the present study was to verify the hypothesis that no difference in biocompatibility exists between different orthodontic adhesives. MATERIAL AND METHODS: Thirty male Wistar rats were used in this study and divided into five groups (n=6): Group 1 (control, distilled water), Group 2 (Concise), Group 3 (Xeno III), Group 4 (Transbond XT), and Group 5 (Transbond plus Self-Etching Primer). Two cavities were performed in the subcutaneous dorsum of each animal to place a polyvinyl sponge soaked with 2 drops of the respective adhesive in each surgical loci. Two animals of each group were sacrificed after 7, 15, and 30 days, and their tissues were analyzed by using an optical microscope. RESULTS: At day 7, Groups 3 (Transbond XT) and 4 (Xeno III) showed intense mono- and polymorphonuclear inflammatory infiltrate with no differences between them, whereas Groups 1 (control) and 2 (Concise) showed moderate mononuclear inflammatory infiltrate. At day 15, severe inflammation was observed in Group 3 (Transbond XT) compared to other groups. At day 30, the same group showed a more expressive mononuclear inflammatory infiltrate compared to other groups. CONCLUSION: Among the orthodontic adhesive analyzed, it may be concluded that Transbond XT exhibited the worst biocompatibility. However, one cannot interpret the specificity of the data generated in vivo animal models as a human response.

Avaliação da liberação de flúor de alginatos odontológicos / Evaluation of fluoride release of dental alginates

Introducao: O proposito do presente trabalho e avaliar a liberacao de fluor de alginatos de uso odontologico. Materiais e Metodos: Foram avaliadas cinco marcas de alginatos divididos em cinco grupos: Jeltrate, Alga Gel, Printer Gel,Ava Gel e New Print. Os alginatos foram manipulados seguindo as orientacoes dos fabricantes. Apos isso, seguiu-se a confeccao dos corpos de prova, utilizando-se moldes de silicone nas dimensoes de 4mm de diametro e 4mm de altura. Apos geleificacao, os corpos de prova foram removidos dos moldes e inseridos em recipiente com 10ml de agua milliQ, por 2min. A liberacao de fluor foi medida, atraves de eletrodo ion seletivo conectado a um analisador de ions. Resultados: O Ava Gel liberou menorquantidade de fluor e foi diferente estatisticamente dos grupos Alga Gel e New Print (P<0,05). O New Print que liberou mais apresentou similaridade estatistica apenas com o grupo Alga Gel que por sua vez foi similar estatisticamente ao Jeltrate e Printer Gel (P> 0.05). Conclusoes: Pode-se concluir com a realizacao deste trabalho que todos os alginatos testados liberaram fluor, um em mais e outros em menor quantidade.

Introduction: The purpose of this study is to evaluate the release of fluoride from alginate for dental use. Materials and Methods: Seventy-five brands of alginate divided into five groups: Jeltrate, Alga Gel, Printer Gel, Ava Gel and New Print. The alginate were handled following the guidelines of the manufacturers. After that begin the making of the specimes using silicone molds of the dimensions of 4 mm in diameter and 4mm in height. After cured the samples were removed from the molds and placed in container with 10 ml of water milliQ, for 2 min. The release of fluoride was measured by ion selective electrode connected to an analyzer of ions. Results: The Ava Gel smaller amount of fluoride released and was statistically different groups of Alga and New Gel Print (P <0.05). The New Print that released more statistics showed similarity only to the group Alga Gel which in turn was statistically similar to Jeltrate and Gel Printer (P> 0.05). Conclusions: All alginate tested released fluoride, and one more in a lesser amount.

Liberação de flúor de alginatos ortodônticos: estudo in vitro / Fluoride release of orthodontics alginate: study in vitro

O propósito do presente trabalho foi avaliar a liberação de flúor de alginatos de uso ortodôntico. Foram avaliadas quatro marcas de alginatos divididos em cinco grupos: Jeltrate, Jeltrate Chromatic Ortho, Cavex Orthotrace e Orthoprint. Os alginatos foram manipulados seguindo as orientações dos fabricantes. Após isso, seguiu-se a confecção dos corpos de prova utilizando moldes de silicone nas dimensões de 4 mm de diâmetro e 4mm de altura. Após geleificação, os corpos de prova foram removidos dos moldes e inseridos em recipiente com 10 ml de água milliQ, por 2 min. A liberação de flúor foi medida, através de eletrodo íon seletivo conectado a um analisador de íons. O Jeltrate foi o material que menos liberou flúor e o Orthoprint o que mais liberou, esses grupos foram estatisticamente diferentes dos demais (P<0.05). Todos os moldes de alginatos liberaram flúor durante o ato de moldagem. O alginato da marca Orthoprint liberou uma quantidade muito alta de flúor.