Bonding brackets on white spot lesions pretreated by means of two methods.

OBJECTIVE: The aim of this study was to evaluate the shear bond strength (SBS) of brackets bonded to demineralized enamel pretreated with low viscosity Icon Infiltrant resin (DMG) and glass ionomer cement (Clinpro XT Varnish, 3M Unitek) with and without aging. METHODS: A total of 75 bovine enamel specimens were allocated into five groups (n = 15). Group 1 was the control group in which the enamel surface was not demineralized. In the other four groups, the surfaces were submitted to cariogenic challenge and white spot lesions were treated. Groups 2 and 3 were treated with Icon Infiltrant resin; Groups 4 and 5, with Clinpro XT Varnish. After treatment, Groups 3 and 5 were artificially aged. Brackets were bonded with Transbond XT adhesive system and SBS was evaluated by means of a universal testing machine. Statistical analysis was performed by one-way analysis of variance followed by Tukey post-hoc test. RESULTS: All groups tested presented shear bond strengths similar to or higher than the control group. Specimens of Group 4 had significantly higher shear bond strength values (p < 0.05) than the others. CONCLUSION: Pretreatment of white spot lesions, with or without aging, did not decrease the SBS of brackets.

Bonding brackets on white spot lesions pretreated by means of two methods

Abstract Objective: The aim of this study was to evaluate the shear bond strength (SBS) of brackets bonded to demineralized enamel pretreated with low viscosity Icon Infiltrant resin (DMG) and glass ionomer cement (Clinpro XT Varnish, 3M Unitek) with and without aging. Methods: A total of 75 bovine enamel specimens were allocated into five groups (n = 15). Group 1 was the control group in which the enamel surface was not demineralized. In the other four groups, the surfaces were submitted to cariogenic challenge and white spot lesions were treated. Groups 2 and 3 were treated with Icon Infiltrant resin; Groups 4 and 5, with Clinpro XT Varnish. After treatment, Groups 3 and 5 were artificially aged. Brackets were bonded with Transbond XT adhesive system and SBS was evaluated by means of a universal testing machine. Statistical analysis was performed by one-way analysis of variance followed by Tukey post-hoc test. Results: All groups tested presented shear bond strengths similar to or higher than the control group. Specimens of Group 4 had significantly higher shear bond strength values (p < 0.05) than the others. Conclusion: Pretreatment of white spot lesions, with or without aging, did not decrease the SBS of brackets.

resumo Introdução: o objetivo do presente estudo foi avaliar a resistência ao cisalhamento de braquetes colados ao esmalte desmineralizado e pré-tratado com uma resina infiltrante de baixa viscosidade (Icon, DMG) ou com um selante ionomérico (Clinpro XT Varnish, 3M Unitek), com e sem envelhecimento. Métodos: setenta e cinco (75) amostras de esmalte bovino foram divididas em cinco grupos (n = 15). No Grupo 1 (controle), a superfície do esmalte não foi desmineralizada. Nos outros quatro grupos, as superfícies foram submetidas ao desafio cariogênico e as lesões de manchas brancas foram tratadas previamente à colagem de braquetes. Nos Grupos 2 e 3, as lesões foram tratadas com a resina Icon; nos Grupos 4 e 5, com o selante Clinpro XT Varnish. Após o tratamento, os Grupos 3 e 5 foram envelhecidos artificialmente. Os braquetes foram colados, sobre as lesões tratadas, utilizando-se o sistema adesivo Transbond XT, e a resistência ao cisalhamento foi avaliada em máquina universal de ensaios. A análise estatística foi realizada por meio da análise de variância e, posteriormente, pelo teste post-hoc de Turkey. Resultados: todos os grupos testados apresentaram resistência ao cisalhamento semelhante ou maior do que o grupo controle. As amostras do Grupo 4 apresentaram valores de resistência ao cisalhamento significativamente maiores (p < 0,05) do que as dos demais grupos. Conclusão: o tratamento das manchas brancas, com ou sem envelhecimento, não diminuiu a resistência ao cisalhamento dos braquetes.

Early vs late orthodontic treatment of tooth crowding by first premolar extraction: A systematic review.

OBJECTIVE: To investigate the body of evidence in the literature about the most favorable time for initiating orthodontic treatment in patients with severe crowding caused by tooth size arch length deficiency (TSALD). MATERIALS AND METHODS: Electronic databases (PubMed, Ovid Medline, Scopus, Virtual Health Library, and The Cochrane Library) were searched for articles published between 1900 and April 2014. Studies were included that evaluated treatment of patients with severe crowding caused TSALD, who were treated with first premolar extraction. The association between the stage of development of occlusion at which treatment was started, and the primary and/or secondary outcomes of early and late treatment were investigated. RESULTS: After application of the eligibility criteria and reading of the full texts, six articles were included in the final review. Of these six articles, all of which were retrospective, four showed that the primary outcome (correction of severe crowding) of the early and late groups was improved, but without statistically significant differences after treatment. Therefore, the findings of secondary outcomes in the literature (postretention crowding relapse, duration of total and active treatment [treatment with appliances], external apical root resorption, and soft tissue profile) were the target of this study. These studies presented low or moderate methodological quality and control of bias. CONCLUSIONS: Both early and late extraction had a similar effect on correction of crowding. Early treatment had two favorable secondary outcomes (less relapse and reduced active treatment time) vs late treatment. However, the levels of evidence were not sufficient to assert which protocol was superior.

Effects of laser vs ultrasound on bone healing after distraction osteogenesis: A histomorphometric analysis.

OBJECTIVE: To assess the effects of low-level laser irradiation vs ultrasound irradiation on bone healing after distraction osteogenesis. MATERIALS AND METHODS: Distraction osteogenesis was performed with rapid maxillary expansion devices (Hyrax-Morelli, Sorocaba, São Paulo Brazil) in 24 rabbits (Oryctolagus cuniculus). After a 2-day latency period, the distraction devices were activated for 10 days at a rate of 1 mm/d. Four groups of six animals were treated as follows: (1) control, (2) laser irradiation on the right side, (3) ultrasound irradiation on the right side, and (4) laser irradiation on the right side and ultrasound on the left side. Histomorphometric analysis was used to assess the bone healing area. Analysis of variance was used to perform the statistical analyses. RESULTS: The influence of low-intensity laser associated with ultrasound irradiation on bone healing was statistically significant. The analyses showed the greatest amount of bone healing in the jaws of animals in group 4, which received treatment with both ultrasound and laser. CONCLUSION: This study concluded that bone healing is accelerated with the application of laser irradiation. The greatest effects were observed with combined ultrasound and laser treatment.

In situ evaluation of orthodontic elastomeric chains.

The hypothesis tested in this study was that intraoral exposure of elastomeric chains alters their tensile strength. For such purpose, it was evaluated the in situ behavior of different elastomeric chains stretched for 3 weeks. Three kinds of elastomeric chains, Plastic chain (PC), Memory chain (MC) and Super slick chain (SSC), were randomly placed in 3 quadrants of 13 patient in a fixed distance of 16 mm and mean initial force of 180 g. Tensile testing was performed in an universal testing machine at different intervals: initial, 1 h, 24 h, 1 week, 2 weeks and 3 weeks. A two-way ANOVA test was performed to identify the influence of both material and time on the force decrease. A subsequent one-way ANOVAtest with the Tukey's post hoc test was used to identify statistically significant intragroup and intergroup remaining force (g and %) differences at 5% significance level. The effect of both the material and the time factors were significant. All groups showed significant force decrease after the 1-h period (23% for PC and 14% for MC and SSC). At the end of the 3-week period, the remaining force was 57% (96 g), 67% (129 g) and 71% (125 g) for PC, MC and SSC, respectively. In conclusion, intraoral exposure of elastomeric chains altered their tensile strength. In general, the greater force decrease occurred within the first hour. The remaining force of the enhanced chains measured at each time interval was greater than the conventional one (PC). After 3 weeks, only the enhanced chains maintained the force applied over 100 g.

Bone mineral density.

OBJECTIVE: To verify whether bone mineral density (BMD) of cortical bone, trabecular bone, and total bone influence the primary stability of orthodontic miniscrews and to verify whether there is a correlation between the measurement of BMD by cone-beam computed tomography (CBCT) and central dual-energy x-ray absorptiometry (DEXA). MATERIALS AND METHODS: Twenty bovine bone sections were extracted from the pubic and iliac bones from regions with cortical thicknesses of approximately 1 mm. The BMD of the total bone block was evaluated using two methods: CBCT and DEXA. The BMD of cortical, trabecular, and total bone in the region of interest (ROI) were also evaluated by CBCT. After scanning the bone blocks, 20 self-drilling miniscrews (INP®) 1.4 mm in diameter and 6 mm long were inserted into them. The peak implant insertion torque (IT) was registered. After this, the pull-out test (PS) was performed and the maximum force registered. The Pearson correlation test was applied to verify the correlations between variables. RESULTS: The BMD of the total bone block verified by CBCT and DEXA showed a positive and strong correlation (r  =  0.866, P  =  .000). The BMD of the ROI for cortical bone influenced the IT (r  =  0.518, P  =  .40) and the PS of miniscrews (r  =  0.713, P  =  .001, Table 2). However, the total bone BMD (verified by CBCT and DEXA) and trabecular bone BMD presented weak and not statistically significant correlations with primary stability. CONCLUSIONS: There was a positive correlation between total bone block BMD measured by DEXA and CBCT. The cortical BMD influenced the IT and PS.

In situ evaluation of orthodontic elastomeric chains

The hypothesis tested in this study was that intraoral exposure of elastomeric chains alters their tensile strength. For such purpose, it was evaluated the in situ behavior of different elastomeric chains stretched for 3 weeks. Three kinds of elastomeric chains, Plastic chain (PC), Memory chain (MC) and Super slick chain (SSC), were randomly placed in 3 quadrants of 13 patient in a fixed distance of 16 mm and mean initial force of 180 g. Tensile testing was performed in an universal testing machine at different intervals: initial, 1 h, 24 h, 1 week, 2 weeks and 3 weeks. A two-way ANOVA test was performed to identify the influence of both material and time on the force decrease. A subsequent one-way ANOVAtest with the Tukey's post hoc test was used to identify statistically significant intragroup and intergroup remaining force (g and %) differences at 5% significance level. The effect of both the material and the time factors were significant. All groups showed significant force decrease after the 1-h period (23% for PC and 14% for MC and SSC). At the end of the 3-week period, the remaining force was 57% (96 g), 67% (129 g) and 71% (125 g) for PC, MC and SSC, respectively. In conclusion, intraoral exposure of elastomeric chains altered their tensile strength. In general, the greater force decrease occurred within the first hour. The remaining force of the enhanced chains measured at each time interval was greater than the conventional one (PC). After 3 weeks, only the enhanced chains maintained the force applied over 100 g.

A hipótese testada foi que a exposição dos elásticos em cadeia ao meio bucal altera sua força de tensão. Portanto, o objetivo deste estudo foi avaliar o comportamento, in situ, de diferentes cadeias elastoméricas quando tensionadas durante 3 semanas. Três tipos de elásticos em cadeia Plastic Chain (PC), Memory Chain (MC) e Super Slick Chain (SSC) foram inseridos aleatoriamente em 3 dos quadrantes de 13 pacientes com distância fixa de 16 mm e força inicial de 180 g. Foi realizado ensaio de tração em uma máquina de ensaio universal EMIC nos seguintes intervalos: inicial, 1 h, 24 h, 1 semana, 2 semanas e 3 semanas. O teste ANOVA a dois critérios foi aplicado para verificar a influência do material e do tempo na degradação da força. Subsequentemente, foi utilizado o teste ANOVA a um critério e pós-teste de Tukey para identificar diferenças estatísticas (p<0,05), intra-grupo e inter-grupo, na força remanescente (g e %). Tanto o material quanto o tempo tiveram efeito significativo na degradação da força. Todos os grupos mostraram diminuição significativa da força depois de 1 h sob tensão (23% para o PC e 14% para o MC e SSC). Ao final do período de 3 semanas, a força remanescente foi de 57% (96 g), 67% (129 g) e 71% (125 g) para o PC, MC e SSC, respectivamente. A exposição dos elásticos em cadeia ao meio bucal alterou a força de tensão. No geral, a maior diminuição da força ocorreu na primeira hora. A força remanescente testada em cada intervalo foi maior para os elásticos reforçados (MC e SSC) do que para o elástico convencional (PC). Após 3 semanas, apenas os elásticos reforçados mantiveram a força acima de 100 g.

Shear bond strengths of orthodontic brackets with a new LED cluster curing light.

OBJECTIVE: To evaluate the shear bond strength of orthodontic brackets bonded to bovine enamel using a new curing appliance composed of an LED cluster. DESIGN: In vitro, laboratory study. MATERIALS AND METHODS: Standard edgewise maxillary central incisor metal brackets (0.022'' slot) were bonded to 60 bovine incisors which were arranged in a parabola, simulating the dental arch. The arches were randomly allocated to one of five groups: three experimental groups in which a half arch was cured using the Whitening Lase Ortho LED Cluster light for 10, 20 and 40 s (EG10s, EG20s, EG40s) and two control groups. Control group 1 (CGH) were cured using a halogen light for 20 s and control group 2 (CGL) were cured using a conventional LED light for 20 s per tooth. A shear debond test was performed using an EMIC machine and the results were analyzed by ANOVA and post hoc Tukey multiple comparisons. The Adhesive Remnant Index (ARI) was determined at 10x magnification. RESULTS: The one-way ANOVA showed a statistically significant difference between the groups (P<0.001). The post hoc Tukey comparison showed that the bond strength for group EG10s was significantly lower than both the control groups CGH (P<0.001) and CGL (P<0.001). There was no significant difference between the bond strengths for groups EG10s and EG20s (P = 0.100). Neither were there any statistically significant differences detected between groups EG20s, EG40s, CGL and CGH (P>0.05).The ARI analysis revealed a higher frequency of score 2 for groups CGL, EG10s, EG20s, a higher frequency of score 0 and 1 for the CGH group and a score of 1 was most frequent for the EG40s group. CONCLUSION: The Whitening Lase Ortho LED Cluster light shows promise when bonding a half dental arch with a curing time of 40 s.