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.

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.

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.