Evaluation of the antibacterial effect of titanium dioxide nanoparticles combined with acrylic laminates for functional orthodontic appliances: a randomized controlled clinical trial.

BACKGROUND: The objective of this study was to evaluate the antibacterial effect of titanium dioxide nanoparticles incorporated into the acrylic baseplates of the maxillary part of twin block appliances in orthodontic patients during the treatment period. MATERIALS AND METHODS: Twenty-six patients were selected randomly and divided into two groups(n = 13). Test group patients used orthodontic functional appliances containing 1% titanium dioxide nanoparticles in acrylic baseplates. Control group patients used orthodontic functional appliances without titanium dioxide nanoparticles in acrylic baseplates. Swap samples were taken from the palatal gingiva facing the fitting surface of the acrylic component of the maxillary part of a twin block appliance for each patient at five-time intervals (baseline sample, after one, two, four, and six months) and then cultured in blood agar plates to calculate bacterial colony count. The Mann‒Whitney U test and the Friedman test were used to compare data. Bonferroni correction (p value ≤ 0.05) was applied to detect significant differences. THE RESULTS: showed a decrease in the bacterial colony count in the test group compared to the control group. Pairwise comparisons revealed a statistically significant difference in samples after four- and six-month groups (p values = 0.002 and 0.011, respectively) vs. the one-month test group. A higher statistically significant difference was observed in the six-month group (p-value = 0.037) vs. the baseline group in the control group. CONCLUSION: The addition of 1% titanium dioxide nanoparticles to acrylic baseplates of orthodontic functional appliances significantly reduced the bacterial colony count under the base plate after at least four months of application.

Antioxidant effect on shear bond strength of orthodontic brackets after tooth bleaching: A scoping review of in vitro studies.

INTRODUCTION: Tooth bleaching was reported to decrease bond strength of orthodontic brackets. The antioxidant application was investigated to reverse the bleaching effect for immediate bracket bonding. This scoping review of in vitro studies is to assess systematically the effect of antioxidant application on shear bond strength (SBS) before orthodontic bracket bonding after tooth bleaching. MATERIALS AND METHODS: This review was provided according to the Preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews (PRISMA-ScR) guidelines. An electronic literature search was performed for full-text articles in English via Scopus, Web of Science, MEDLINE/PubMed, and Google Scholar databases from 2012 to May 9, 2023. RESULTS: A total of 549 records were retrieved from the electronic search, and 361 after discarding duplicates. According to eligibility criteria, 23 records were included in this study. CONCLUSION: Included studies revealed that antioxidants could increase the SBS of brackets after bleaching. However, there was controversiality whether SBS was just improved or restored to the unbleached level according to various factors, including the antioxidant type, concentration, application time, and form. Most studies reported that 10% sodium ascorbate (SA), ascorbic acid, green tea (GT), and tocopherol solutions restored SBS of metal brackets but not ceramic brackets. The result of 10% SA and GT gel was controversial. Lower concentrations than 10% was effective with pink bark, grape seed, quercetin flavonoid, and chamomile to restore SBS. The included studies revealed that retinol acetate, gooseberry, and dimethyl sulfoxide did not restore SBS.

Can antioxidant treatment replace delay in bracket bonding? An in vitro study.

BACKGROUND: Deterioration in shear bond strength has been reported after immediate bracket bonding following hydrogen peroxide bleaching. This study compared the effectiveness of three antioxidant agents, namely, alpha-tocopherol, green tea extract, and sodium ascorbate, in reversing the bleaching effect and as possible alternatives to delayed bonding. METHODS: A total of 105 extracted human premolars were arbitrarily assigned to 7 groups (n = 15 each), including group 1 as the unbleached control group and six experimental groups, which were bleached with 40% hydrogen peroxide in three sessions of 15 min each. In experimental group 2, bonding was performed immediately after bleaching, whereas in groups 3 and 4, bonding was delayed for 1 and 2 weeks, respectively; meanwhile, the specimens were immersed in artificial saliva at 37 °C. Groups 5, 6, and 7 were treated immediately after bleaching with 10% of alpha-tocopherol, green tea extract, and sodium ascorbate solutions, respectively, for 15 min. Specimens were processed using 500 thermal cycles between 5 and 55 °C, with a dwell time of 30 s after 24 h of bracket bonding, and then tested for shear bond strength. The adhesive remnant index was examined to evaluate fracture mode. One-way analysis of variance, Kruskal-Wallis H, and post hoc Tukey's honestly significant difference tests were used to compare the data. Significant results were subjected to pairwise comparisons with Bonferroni's correction-adjusted of p values ≤ 0.050. RESULTS: Shear bond strength was significantly lower (p < 0.001) in the immediate bonding and 1-week delay groups than in the control group. However, no significant difference was detected among the 2-week delay, antioxidant-treated, and control groups (p > 0.05). CONCLUSIONS: Application of 10% alpha-tocopherol, green tea extract, or sodium ascorbate for 15 min could restore shear bond strength after 40% hydrogen peroxide bleaching as an alternative to delay in bracket bonding.

The effects of micro-osteoperforation on upper first molar root resorption and bone density after distalization by miniscrew-supported Fast Back appliance in adults: A CBCT randomized controlled trial.

OBJECTIVE: To evaluate, primary the effects of Micro-osteoperforation (MOP) on orthodontically induced inflammatory root resorption (OIIRR) of maxillary first molars, and secondary, the density of surrounding alveolar bone during distalization phase with Fast Back distalizer. MATERIALS AND METHODS: Female patients between 16-20 years of age (University of Mansoura), meeting the criteria, were included between March to September 2019. They were randomly, and equally allocated into control and MOP groups. Both of them underwent distalization with Fast Back distalizer. 3MOPs were applied in the intervention group, distal to the first molars using a 3D printed guide. CBCT images were obtained before and after distalization. Apical root resorption maxillary first molars' roots, and alveolar bone density surrounding them were evaluated using independent-samples t-test. Time of distalization phase was assessed using Mann-Whitney U test. Correlation and partial correlation tests were done between resorption of roots, bone density, and time. RESULTS: Screening of 50 patients, and exclusion for 30 of them were done. Only 20 subjects underwent the trial to the end. In MOP group, OIIRR of mesiobuccal roots significantly increased (MD=-0.2 (-0.34 to -0.01), P<0.05), and significantly decreased for disto-buccal roots (MD=0.6 (0.45 to 0.72), P<0.001). The second and third layers of bone density decreased significantly in MOP group (MD=116.7 (50.8 to 182.5), MD=560.4 (327.9 to 792.7) respectively, P<0.001). Time for distalization phase was significantly reduced in MOP group (P<0.001). CONCLUSIONS: MOP decreased OIIRR for nearby distobuccal roots by reduction in surrounding density of bone, and increased OIIRR for the far mesiobuccal roots.