Bone formation in sinus augmentation with different xenograft particle sizes: systematic review and meta-analysis / Formação óssea em levantamento de seio maxilar com diferentes tamanhos de partículas de enxerto xenográfico: revisão sistemática e meta-análise

ABSTRACT The commercial bovine bone mineral most commonly used is available in two particle sizes and studies have demonstrated contradictory results regarding bone formation volume using small or large particles. The aim of this systematic review and meta-analysis was to compare the bone formation volume and residual bovine bone volume in sinus floor augmentation using small and large particles. The following outcome measures were assessed: bone formation volume (%) and residual bovine bone particles volume (%) assessed by histomorphometric analysis. The initial screening resulted in 236 records. After removal of duplicated articles and analysis of titles, abstracts and full texts, three articles were included in the meta-analysis. The bone formation volume and residual bovine bone volume did not differ between small and large particles, with low heterogeneity of studies. The particle size of bovine bone mineral did not influence bone formation percentage; small and large particles of bovine bone graft presented similar residual bone mineral; more randomized clinical trials should be performed to completely confirm that bovine bone mineral particle size does not affect the result of sinus floor augmentation.

RESUMO O enxerto ósseo bovino comercial mais comumente utilizado está disponível em dois tamanhos de partícula, que tem demonstrado resultados contraditórios em relação à formação óssea usando partículas pequenas ou grandes. O objetivo desta revisão sistemática e meta-análise é comparar o volume de formação óssea e o volume de enxerto residual em levantamento de seio usando partículas pequenas e grandes. Os seguintes dados foram comparados: volume de formação óssea (%) e volume residual de partículas de enxerto (%) dados por análise histomorfométrica. A seleção inicial resultou em 236 artigos. Após remoção de artigos duplicados e análise dos títulos, resumos e textos completos, três artigos foram incluídos na meta-análise. Os volumes de formação óssea e de enxerto residual não diferenciam entre os tamanhos de partícula pequeno e grande, com baixa heterogeneidade dos artigos. O tamanho de partícula de enxerto ósseo bovino não influencia o percentual de formação óssea; partículas de enxerto ósseo bovino pequenas e grandes apresentaram enxerto residual similar; mais ensaios clínicos randomizados deveriam ser realizados para confirmar que o tamanho de partícula de enxerto não afeta os resultados de levantamento de seio maxilar.

Láser de baja intensidad en pulpotomía de dientes primarios / Laser de baixa intensidade em pulpotomia de dentes decíduos / Low-level laser in pulpotomy of deciduous teeth

Las altas tasas de lesiones cariosas en niños y adolescentes pueden resultar en la exposición pulpar o incluso en la pérdida temprana del diente primario, situación que requiere una acción mínimamente invasiva por parte del odontólogo, para preservar el diente en la cavidad bucal. La pulpotomía, un tipo de terapia pulpar vital destinada a tratar de forma reversible las lesiones relacionadas con la cámara pulpar, utiliza diferentes técnicas para mantener el diente vital en la cavidad oral hasta la exfoliación. Objetivo: demostrar la efectividad de la técnica de Terapia Láser de Baja Intensidad (LBI) en comparación con el Hidróxido de Calcio en el procedimiento de pulpotomía de dientes primarios. Materiales y Métodos: La investigación fue un ensayo clínico longitudinal con nueve molares primarios de niños de 5 a 12 años. Las evaluaciones clínicas y radiográficas se realizaron después de períodos de 1, 2, 3 y 6 meses. Resultados: Hubo un índice de éxito clínico en cuanto a ausencia de dolor, sensibilidad a la percusión, inflamación y, radiográficamente, ausencia de resorción interna o externa o lesiones de furca en el 100% de los casos. Conclusión: El LBI demuestra beneficios como la ausencia de dolor, el efecto antiinflamatorio y la ausencia de efectos adversos. Por tanto, se sugiere que la LBI puede considerarse una técnica alternativa para la pulpotomía en la práctica clínica. Sin embargo, se recomiendan más estudios clínicos sobre el tema

: Os índices elevados de lesões cariosas em crianças e adolescentes podem resultar em exposição da polpa ou até mesmo na perda precoce do dente decíduo, situação que exige atuação minimamente invasiva do cirurgião-dentista, visando preservar o dente na cavidade bucal. A pulpotomia, um tipo de terapia pulpar vital que visa tratar de forma reversível as injúrias relacionadas à câmara pulpar, utiliza diferentes técnicas com a finalidade de manter o dente vital na cavidade bucal até a sua esfoliação. Objetivo: evidenciar a eficácia da técnica de Laser terapia de Baixa Intensidade (LBI) comparada com o Hidróxido de Cálcio no procedimento de pulpotomia de dentes decíduos. Materiais e método: A pesquisa foi um ensaio clínico longitudinal com nove molares decíduos de crianças com idade entre 5 e 12 anos. Foram realizadas avaliações clínicas e radiográficas após os períodos de 1, 2, 3 e 6 meses. Resultados: Observou-se índice de sucesso clínico quanto à ausência de dor, de sensibilidade à percussão, de inchaço anormal e, radiograficamente, de ausência de reabsorção interna ou de externa ou lesão de furca em 100% dos casos. Conclusão: O LBI demonstra benefícios como a ausência de dor, o efeito anti-inflamatório e a ausência de efeitos adversos. Desta forma, sugere-se que o LBI possa ser considerado uma técnica alternativa para pulpotomia na prática clínica. Porém recomenda-se mais estudos clínicos sobre o assunt

The high rates of carious lesions in children and adolescents can result in pulp exposure or even early loss of the primary tooth, a situation that requires minimally invasive action by the dentist, in order to preserve the tooth in the oral cavity. Pulpotomy, a type of vital pulp therapy aimed at reversibly treating injuries related to the pulp chamber, uses different techniques in order to keep the vital tooth in the oral cavity until exfoliation. Aim: to demonstrate the effectiveness of the Low Intensity Laser Therapy (LBI) technique compared to Calcium Hydroxide in the pulpotomy procedure of primary teeth. Materials and methods: The research was a longitudinal clinical trial with nine primary molars of children aged 5 to 12 years. Clinical and radiographic evaluations were performed after periods of 1, 2, 3 and 6 months. Results: There was an index of clinical success regarding the absence of pain, sensitivity to percussion, abnormal swelling and, radiographically, the absence of internal or external resorption or furcation lesions in 100% of the cases. Conclusion: The LBI demonstrates benefits such as the absence of pain, the anti-inflammatory effect and the absence of adverse effects. Thus, it is suggested that LBI can be considered an alternative technique for pulpotomy in clinical practice. However, further clinical studies on the subject are recommended

Boron Nitride Nanotubes as Filler for Resin-Based Dental Sealants.

The aim of this study was to evaluate the influence of boron-nitride nanotubes (BNNTs) on the properties of resin-based light-curing dental sealants (RBSs) when incorporated at different concentration. RBSs were formulated using methacrylate monomers (90 wt.% TEGDMA, 10 wt.% Bis-GMA). BNNTs were added to the resin blend at 0.1 wt.% and 0.2 wt.%. A Control group without filler was also designed. Degree of conversion, ultimate tensile strength, contact angle, surface free energy, surface roughness and color of the RBSs were evaluated for the tested materials. Their cytotoxicity and mineral deposition ability (Bioactivity) were also assessed. A suitable degree of conversion, no effect in mechanical properties and no cytotoxic effect was observed for the experimental materials. Moreover, the surface free energy and the surface roughness decreased with the addition of BNNTs. While the color analysis showed no difference between specimens containing BNNTs and the control group. Mineral deposition occurred in all specimens containing BNNTs after 7d. In conclusion, the incorporation of BNNTs may provide bioactivity to resin-based dental sealants and reduce their surface free energy.

Evaluation of an antibacterial orthodontic adhesive incorporated with niobium-based bioglass: an in situ study.

This in situ study aimed to evaluate the antibacterial and anti-demineralization effects of an experimental orthodontic adhesive containing triazine and niobium phosphate bioglass (TAT) around brackets bonded to enamel surfaces. Sixteen volunteers were selected to use intra-oral devices with six metallic brackets bonded to enamel blocks. The experimental orthodontic adhesives were composed by 75% BisGMA and 25% TEGDMA containing 0% TAT and 20% TAT. Transbond XT adhesive (TXT) was used as a control group. Ten volunteers, mean age of 29 years, were included in the study. The six blocks of each volunteer were detached from the appliance after 7 and 14 days to evaluate mineral loss and bacterial growth including total bacteria, total Streptococci, Streptococci mutans, and Lactobacilli. Statistical analysis was performed using GLM model - univariate analysis of variance for microhardness and 2-way ANOVA for bacterial growth (p<0.05). The 20% TAT adhesive caused no difference between distances from bracket and the sound zone at 10-µm deep after 7 and 14 days. After 14 days, higher mineral loss was shown around brackets at 10- to 30-µm deep for TXT and 0% TAT adhesives compared to 20% TAT. S. mutans growth was inhibited by 20% TAT adhesive at 14 days. Adhesive with 20% TAT showed lower S. mutans and total Streptococci growth than 0% TAT and TXT adhesives. The findings of this study show that the adhesive incorporated by triazine and niobium phosphate bioglass had an anti-demineralization effect while inhibiting S. mutans and total Streptococci growth. The use of this product may inhibit mineral loss of enamel, preventing the formation of white spot lesions.

Antibacterial and Remineralizing Fillers in Experimental Orthodontic Adhesives.

Orthodontic adhesives with antimicrobial and remineralizing properties may be an alternative to control white spot lesions around brackets. The aim of this study is to develop an experimental orthodontic adhesive containing boron nitride nanotubes (BNNT) and alkyl trimethyl ammonium bromide (ATAB). Methacrylate (BisGMA and TEGDMA) monomers were used to formulate the adhesives. Four experimental groups were produced with the addition of 0.1 wt.% BNNT (GBNNT); 0.1 wt.% ATAB (GATAB); and 0.2 wt.% BNNT with ATAB (GBNNT/ATAB); in the control group, no fillers were added (GCtrl). The degree of conversion, cytotoxicity, softening in solvent, contact angle and free surface energy, antibacterial activity, shear bond strength, and mineral deposition were evaluated. Adhesives achieved degree of conversion higher than 50% and cell viability higher than 90%. GBNNT and GATAB adhesives exhibited reduced softening in solvent. Mean free surface energy was decreased in the GBNNT adhesive. Significant reduction in bacterial growth was observed in the GBNNT/ATAB. No statistical difference was found for shear bond strength. Mineral deposition was found in GBNNT, GATAB, and GBNNT/ATAB groups after 14 and 28 days. The addition of 0.2% BNNT/ATAB to an experimental orthodontic adhesive inhibited bacterial growth and induced mineral deposition without affecting the properties of the material.

Evaluation of an antibacterial orthodontic adhesive incorporated with niobium-based bioglass: an in situ study

Abstract This in situ study aimed to evaluate the antibacterial and anti-demineralization effects of an experimental orthodontic adhesive containing triazine and niobium phosphate bioglass (TAT) around brackets bonded to enamel surfaces. Sixteen volunteers were selected to use intra-oral devices with six metallic brackets bonded to enamel blocks. The experimental orthodontic adhesives were composed by 75% BisGMA and 25% TEGDMA containing 0% TAT and 20% TAT. Transbond XT adhesive (TXT) was used as a control group. Ten volunteers, mean age of 29 years, were included in the study. The six blocks of each volunteer were detached from the appliance after 7 and 14 days to evaluate mineral loss and bacterial growth including total bacteria, total Streptococci, Streptococci mutans, and Lactobacilli. Statistical analysis was performed using GLM model - univariate analysis of variance for microhardness and 2-way ANOVA for bacterial growth (p<0.05). The 20% TAT adhesive caused no difference between distances from bracket and the sound zone at 10-µm deep after 7 and 14 days. After 14 days, higher mineral loss was shown around brackets at 10- to 30-µm deep for TXT and 0% TAT adhesives compared to 20% TAT. S. mutans growth was inhibited by 20% TAT adhesive at 14 days. Adhesive with 20% TAT showed lower S. mutans and total Streptococci growth than 0% TAT and TXT adhesives. The findings of this study show that the adhesive incorporated by triazine and niobium phosphate bioglass had an anti-demineralization effect while inhibiting S. mutans and total Streptococci growth. The use of this product may inhibit mineral loss of enamel, preventing the formation of white spot lesions.

Enamel Roughness Changes after Removal of Orthodontic Adhesive.

The aim of this study was to evaluate enamel roughness, quality of the enamel surfaces and time duration comparing different orthodontic adhesive removal protocols. Premolars were used to test three adhesive removal methods (n = 20): five-blade carbide bur, 30-blade carbide bur, and ultrasonic diamond bur. Bracket was bonded using TransbondTM XT adhesive. Roughness with different parameters was measured before bracket bonding and after adhesive remnants removal. Micromorphological analysis of enamel surface (n = 5) was performed by SEM images and categorized in enamel damage index-"perfect"; "satisfying"; "imperfect"; and "unacceptable". Time was measured in seconds. All removal methods caused increased roughness in relation to Ra, Rq, and Rz parameters (X axis) comparing to healthy enamel surface. Enamel surface resulted from removal using five-blade burs was scored as satisfactory. Carbide bur groups decreased the roughness values of Ra, Rq, and Rz parameters on the Y axis and enamel surface was considered unacceptable. The 30-blade group increased symmetry (Rsk) and flattening (Rku) parameters of roughness and surface was scored as unsatisfactory. Diamond bur removed adhesive in 54.8 s, faster than five-blade carbide bur. The five-blade bur group resulted in less enamel roughness than the 30-blade and diamond groups.

Physicochemical and Microbiological Assessment of an Experimental Composite Doped with Triclosan-Loaded Halloysite Nanotubes.

This study is aimed at evaluating the effects of triclosan-encapsulated halloysite nanotubes (HNT/TCN) on the physicochemical and microbiological properties of an experimental dental composite. A resin composite doped with HNT/TCN (8% w/w), a control resin composite without nanotubes (HNT/TCN-0%) and a commercial nanofilled resin (CN) were assessed for degree of conversion (DC), flexural strength (FS), flexural modulus (FM), polymerization stress (PS), dynamic thermomechanical (DMA) and thermogravimetric analysis (TGA). The antibacterial properties (M) were also evaluated using a 5-day biofilm assay (CFU/mL). Data was submitted to one-way ANOVA and Tukey tests. There was no significant statistical difference in DC, FM and RU between the tested composites (p > 0.05). The FS and CN values attained with the HNT/TCN composite were higher (p < 0.05) than those obtained with the HNT/TCN-0%. The DMA analysis showed significant differences in the TAN δ (p = 0.006) and Tg (p = 0) between the groups. TGA curves showed significant differences between the groups in terms of degradation (p = 0.046) and weight loss (p = 0.317). The addition of HNT/TCN induced higher PS, although no significant antimicrobial effect was observed (p = 0.977) between the groups for CFUs and (p = 0.557) dry weight. The incorporation of HNT/TCN showed improvements in physicochemical and mechanical properties of resin composites. Such material may represent an alternative choice for therapeutic restorative treatments, although no significance was found in terms of antibacterial properties. However, it is possible that current antibacterial tests, as the one used in this laboratory study, may not be totally appropriate for the evaluation of resin composites, unless accompanied with aging protocols (e.g., thermocycling and load cycling) that allow the release of therapeutic agents incorporated in such materials.

Long-term stability of dental adhesive incorporated by boron nitride nanotubes.

OBJECTIVE: The aim of this study was to evaluate physicochemical properties, long-term microtensile bond strength and cytotoxicity of methacrylate-based adhesive containing boron nitride nanotubes (BNNTs) as fillers. METHODS: A dental adhesive was formulated using BisGMA/HEMA, 66/33wt% (control). Inorganic BNNT fillers were incorporated into the adhesive at different concentrations (0.05, 0.075, 0.1 and 0.15wt%). Analyses of degree of conversion (DC), polymerization rate [Rp.(s-1)], contact angle (CA) on dentin, after 24h and 6 months microtensile bond strength (µTBS-24h and 6 months) were assessed. Cytotoxicity was performed through viability of fibroblast cells (%) by sulforhodamine B (SRB) colorimetry. RESULTS: DC and max. polymerization rate increased (p<0.05) after incorporating 0.075 and 0.1wt% BNNT. The contact angle on dentin increased (p<0.05) after incorporating 0.15wt% BNNT. The µTBS-24h showed no changes (p>0.05) after incorporating up to 0.15wt% BNNT comparing to control. After 6 months, µTBS decreased (p<0.05) for control and 0.15wt% BNNT and BNNT groups up to 0.15wt% showed higher µTBS than control (p<0.05). No difference of fibroblast growth was found among adhesives (p>0.05) and up to 19% of cell viability was found comparing 0.05wt% BNNT to positive control group (100%). SIGNIFICANCE: Incorporating boron nitride nanotubes up to 0.1wt% into dental adhesive increased the long-term stability to dentin without decreasing viability of fibroblast cell growth. Thus, the use of BNNTs as filler may decrease failure rate of current dentinal adhesives.

Polymerisation, antibacterial and bioactivity properties of experimental orthodontic adhesives containing triclosan-loaded halloysite nanotubes.

OBJECTIVE: To evaluate the immediate enamel bond strength, in situ degree of conversion and the polymerisation rate of three experimental orthodontic adhesives containing triclosan-loaded halloysite nanotubes. The antibacterial and bioactivity properties of such experimental materials were also assessed. MATERIALS AND METHODS: Three experimental orthodontic adhesives were formulated by incorporating triclosan-loaded halloysite nanotubes (TCN-HNT) at different concentrations (5wt%, 10wt% and 20wt%) into a resin blend (Control). The maximum polymerisation rate of the tested adhesives was evaluated trough FTIR, while Raman was used to analyse the in situ degree of conversion (DC) at the bracket/enamel interface. The shear bond strength (SBS) of the enamel-bonded specimens was assessed at 24h. The antibacterial properties of the experimental materials against S. Mutans were evaluate up to 72h, while, their bioactivity was evaluated after 14days of artificial saliva (AS) storage through SEM-EDS and Raman spectromicroscopy. RESULTS: Incorporation of TCN-HNT increased the polymerisation properties without interfering with the immediate bonding properties of the experimental adhesives. All experimental adhesives containing TCN-HNT inhibited bacterial growth at 24h, and induced mineral deposition after 14days of AS storage. At 72h, only the experimental system containing 20% TCN-HNT maintained such a capability. CONCLUSIONS: Adhesives doped with TCN-HNT present improved polymerisation properties and suitable bonding performance. However, only the adhesives containing TCN-HNT >10% might promote long-term antibacterial activity and reliable mineral deposition. CLINICAL SIGNIFICANCE: The use of adhesives containing triclosan-loaded halloysite represents a promising "smart" approach to bond orthodontic brackets and bands; these might prevent enamel demineralisation and induce enamel remineralisation during the treatment.

Boron nitride nanotubes as novel fillers for improving the properties of dental adhesives.

OBJECTIVE: This study aimed to evaluate the physical-chemical properties of experimental dental adhesives containing boron nitride nanotubes (BNNTs) as inorganic fillers. METHODS: An experimental adhesive resin was prepared using HEMA-BisGMA, 66/33wt% (control). Inorganic BNNT fillers were first analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and then incorporated into the adhesive at different concentration (0.05, 0.075, 0.1, 0.15wt%). Degree of conversion (DC), ultimate strength, contact angle, surface free energy (SFE) microhardness, softening in solvent and bioactivity were assessed. RESULTS: Scanning and transmission electron microscopy (SEM and TEM) showed BNNTs with diameter ranging from 5 to 10nm with close end tips. No changes in DC were observed after incorporating BNNTs up to 0.15wt%. The contact angles of water and α-bromonaphthalene increased (p<0.05) and consequently the SFE decreased after incorporating BNNTs to the polymer matrix. Microhardness and solvent degradation strength increased after incorporation of 0.075, 0.1 and 0.15wt% BNNTs. Mineral deposition was found after 7days of immersion on adhesive specimens after incorporation of BNNT. CONCLUSIONS: The incorporation of BNNTs up to 0.15wt% improved the chemical and mechanical properties of dental adhesives and promoted mineral deposition. CLINICAL SIGNIFICANCE: Incorporation of boron nitride nanotubes into adhesive resin materials improved physical-chemical properties and increased mineral deposition on its surface allowing enhanced properties of the resin-dentin interface. Thus, the novel adhesive material is promising as a dental adhesive and may contribute to the stability of the dentin-resin bonding.

Effect of silver nanoparticles on the physicochemical and antimicrobial properties of an orthodontic adhesive.

OBJECTIVE: This study aimed to incorporate silver nanoparticle solutions (AgNP) in an orthodontic adhesive and evaluate its physicochemical and antimicrobial properties. MATERIAL AND METHODS: Silver nanoparticle solutions were added to a commercial adhesive in different concentrations (w/w): 0%, 0.11%, 0.18%, and 0.33%. Shear bond strength (SBS) test was performed after bonding metal brackets to enamel. Raman spectroscopy was used to analyze in situ the degree of conversion (DC) of the adhesive layer. The surface free energy (SFE) was evaluated after the measurement of contact angles. Growth inhibition of Streptococcus mutans in liquid and solid media was determined by colony-forming unit count and inhibition halo, respectively. One-way ANOVA was performed for SBS, DC, SFE, and growth inhibition. RESULTS: The incorporation of AgNP solution decreased the SBS (p<0.001) and DC in situ (p<0.001) values. SFE decreased after addition of 0.18% and 0.33% AgNP. Growth inhibition of S. mutans in liquid media was obtained after silver addition (p<0.05). CONCLUSIONS: The addition of AgNP solutions to Transbond™ XT adhesive primer inhibited S. mutans growth. SBS, DC, and SFE values decreased after incorporation up to 0.33% AgNP solution without compromising the chemical and physical properties of the adhesive.

Effect of silver nanoparticles on the physicochemical and antimicrobial properties of an orthodontic adhesive

ABSTRACT Orthodontic treatment with fixed brackets plays a major role on the formation of white spot lesions. Objective This study aimed to incorporate silver nanoparticle solutions (AgNP) in an orthodontic adhesive and evaluate its physicochemical and antimicrobial properties. Material and Methods Silver nanoparticle solutions were added to a commercial adhesive in different concentrations (w/w): 0%, 0.11%, 0.18%, and 0.33%. Shear bond strength (SBS) test was performed after bonding metal brackets to enamel. Raman spectroscopy was used to analyze in situ the degree of conversion (DC) of the adhesive layer. The surface free energy (SFE) was evaluated after the measurement of contact angles. Growth inhibition of Streptococcus mutans in liquid and solid media was determined by colony-forming unit count and inhibition halo, respectively. One-way ANOVA was performed for SBS, DC, SFE, and growth inhibition. Results The incorporation of AgNP solution decreased the SBS (p<0.001) and DC in situ (p<0.001) values. SFE decreased after addition of 0.18% and 0.33% AgNP. Growth inhibition of S. mutans in liquid media was obtained after silver addition (p<0.05). Conclusions The addition of AgNP solutions to Transbond™ XT adhesive primer inhibited S. mutans growth. SBS, DC, and SFE values decreased after incorporation up to 0.33% AgNP solution without compromising the chemical and physical properties of the adhesive.

Physicochemical and bioactive properties of innovative resin-based materials containing functional halloysite-nanotubes fillers.

OBJECTIVE: This study aimed to assess the degree of conversion, microhardness, solvent degradation, contact angle, surface free energy and bioactivity (e.g., mineral precipitation) of experimental resin-based materials containing, pure or triclosan-encapsulated, aluminosilicate-(halloysite) nanotubes. METHODS: An experimental resin blend was prepared using bis-GMA/TEGDMA, 75/25wt% (control). Halloysite nanotubes (HNT) doped with or without triclosan (TCN) were first analyzed using transmission electron microscopy (TEM). HNT or HNT/TCN fillers were incorporated into the resin blend at different concentrations (5, 10, and 20wt%). Seven experimental resins were created and the degree of conversion, microhardness, solvent degradation and contact angle were assessed. Bioactive mineral precipitation induced by the experimental resins was evaluated through Raman spectroscopy and SEM-EDX. RESULTS: TEM showed a clear presence of TCN particles inside the tubular lumen and along the outer surfaces of the halloysite nanotubes. The degree of conversion, surface free energy, microhardness, and mineral deposition of polymers increased with higher amount of HNTs. Conversely, the higher the amount (20wt%) of TCN-loaded HNTs the lower the microhardness of the experimental resins. SIGNIFICANCE: The incorporation of pure or TCN-loaded aluminosilicate-(halloysite) nanotubes into resin-based materials increase the bioactivity of such experimental restorative materials and promotes mineral deposition. Therefore, innovative resin-based materials containing functional halloysite-nanotube fillers may represent a valuable alternative for therapeutic minimally invasive treatments.

Orthodontic bracket bonding without previous adhesive priming: A meta-regression analysis.

OBJECTIVE: To determine the consensus among studies that adhesive resin application improves the bond strength of orthodontic brackets and the association of methodological variables on the influence of bond strength outcome. MATERIALS AND METHODS: In vitro studies were selected to answer whether adhesive resin application increases the immediate shear bond strength of metal orthodontic brackets bonded with a photo-cured orthodontic adhesive. Studies included were those comparing a group having adhesive resin to a group without adhesive resin with the primary outcome measurement shear bond strength in MPa. A systematic electronic search was performed in PubMed and Scopus databases. RESULTS: Nine studies were included in the analysis. Based on the pooled data and due to a high heterogeneity among studies (I(2)  =  93.3), a meta-regression analysis was conducted. The analysis demonstrated that five experimental conditions explained 86.1% of heterogeneity and four of them had significantly affected in vitro shear bond testing. The shear bond strength of metal brackets was not significantly affected when bonded with adhesive resin, when compared to those without adhesive resin. CONCLUSIONS: The adhesive resin application can be set aside during metal bracket bonding to enamel regardless of the type of orthodontic adhesive used.

Effect of surface treatment of brackets and mechanical cycling on adhesion to enamel.

This in vitro study sought to evaluate how surface conditioning from bracket and mechanical cycling aging affected the bond strength between metallic brackets and bovine enamel, and to determine the adhesive remnant index. Eighty bovine incisors were embedded in acrylic resin using polyvinyl chloride rings and divided into 4 groups based on surface treatment (n = 20). Group 1 (control) received no surface treatment, Group 2 specimens were sandblasted with aluminum oxide particles, Group 3 specimens were sandblasted with silicon oxide and treated with a tribochemichemical silica coupling agent, and Group 4 specimens were primed with a multidomain protein-based agent. Half of the specimens were submitted to shear bond testing, while the others were subjected to mechanical cycling. ANOVA showed that mechanical cycling did not have a significant influence on bond strength (P = 0.9244), while surface conditioning of the brackets did (P = 0.0001). Tukey's test results were similar for mechanical cycling, and indicated that only Group 3 significantly improved the resin bond to the brackets; however, this group also demonstrated the highest percentage of enamel failure.

Influence of dental erosion on the shear bond strength of orthodontic brackets: an in vitro study / Influência da erosão dentária sobre a resistência adesiva ao cisalhamento de bráquetes ortodônticos: um estudo in vitro

Objective: evaluate the shear bond strength of metallic brackets bonded with two adhesive systems to eroded enamel surfaces. Methods: sixty bovine incisors were used and divided into four groups (n = 15). The bonding procedures were performed with metallic brackets and 37% phosphoric acid etching, and divided as follows: Group 1, healthy enamel with Transbond XT adhesive system (3M Unitek, Monrovia, USA); Group 2, eroded enamel with Transbond XT adhesive system; Group 3, healthy enamel with Orthoprimer/Orthobond adhesive system (Dental Morelli Ltda, Sorocaba, Brazil); and Group 4, eroded enamel with Orthoprimer/Orthobond adhesive system. Teeth erosion was performed with Classic CokeTM during 14 days. After 24 h of bonding procedures, specimens were subjected to shear loading using a universal machine for mechanical testing at a crosshead speed of 1 mm/min. Results: the shear bond strength means were: Group 1, 19.04(3.24) MPa; Group 2, 18.6(4.25) MPa; Group 3, 12.76(2.78) MPa; and Group 4, 13.01(3.22) MPa. No statistically significant differences were found between groups 1 and 2, and between groups 3 and 4. Statistically significant differences were found between groups 1 and 3, and between groups 2 and 4. The adhesive remnant index (ARI) scores indicated no significant differences among the tested groups. Conclusions: acid erosion did not change shear bond strength of metallic brackets bonded with both adhesive systems. Transbond XT adhesive system showed higher shear bond strength than Orthoprimer/Orthobond adhesive system.