The color improvement of postdebonding white spot lesions after fluoride and casein phosphopeptide- amorphous calcium phosphate application.

White spots are common side effects of orthodontic treatment, and their presence after debonding appears unesthetic. This study aimed to quantify and compare the visual improvement in postdebonding white spot lesions following fluoride and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application. The sample included 42 upper premolars extracted for orthodontic reasons. Universal premolar brackets were bonded to the facial surfaces of the teeth that were exposed to a demineralization solution to create artificial white spot lesions, after which the brackets were debonded. The specimens were randomly allocated to three treatment groups (n = 14, each): acidulated phosphate fluoride (APF) gel application group; CPP-ACP paste application group; and control group. pH cycling was conducted to all groups for 14 days. Quantitative measurements were carried out using a spectrophotometer at the following times: before and after the white spot lesions artificially formed and after treating them. All groups showed significant differences in color change before and after treatment. However, there was no significant difference in the color improvement between the APF gel and CPP-ACP paste application groups. Although CPP-ACP application improved the color of the white spot lesions, it did not differ significantly from that of fluoride application.

The effect of coating chitosan on Porphyromonas gingivalis biofilm formation in the surface of orthodontic mini-implant.

Infection is the main problem for the failure of orthodontic mini-implant. Modern prevention of infection is now focused on local antibacterial coatings on implant devices. Chitosan is biocompatible and has antibacterial properties. Azithromycin is a synthetic antibiotic with immunomodulatory properties in which it has an advantage over the rest of antibiotics. This study aimed to evaluate the effect coating chitosan on the orthodontic mini-implant in Porphyromonas gingivalis biofilm formation. This is an experimental study using 25 orthodontic mini-implants. Five samples were coated with chitosan, 5 samples were coated with chitosan-azithromycin, 5 samples were coated with azithromycin, 5 samples were uncoated, and 5 samples were uncoated and were not exposed to P. gingivalis. P. gingivalis biofilms on the surface of the orthodontic mini-implant were observed after 24 h of incubation. P. gingivalis biofilm mass inhibition was highest in the azithromycin-treated group, followed by chitosan + azithromycin and chitosan only. The one-way ANOVA statistic test and post hoc Bonferroni statistic test of P. gingivalis biofilm mass show a significant difference between and within groups of experiments (P < 0.05). The Pearson correlation test with a value of R = +0.88, indicated that the bacterial viability count and the biofilm mass have a strong positive correlation. In conclusion, orthodontic mini-implant coated with chitosan, chitosan with azithromycin, or azithromycin only effectively suppressed P. gingivalis biofilm formation.

Corrosion Resistance of Stainless Steel Brackets After Thermal Recycling by Direct Flaming

Objective: To determine and compare the corrosion resistance (based on the release of nickel and chromium in artificial saliva) of various brands of stainless steel brackets after thermal recycling by direct flaming. Material and Methods: This research study employed 40 stainlesssteel maxillary premolar brackets from different brands (Ormco, GAC, Versadent, S-Ortho, and Protect), which were divided into 5 groups consisting of 8 brackets. The nickel and chromium content of the metal brackets were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), conducted before immersion. For the first treatment, each group was immersed in artificial saliva without direct flaming (recycling); for the second treatment, each group was immersed in artificial saliva with direct flaming (recycling) for 30 days in a pH-neutral (pH=7) solution. ICP-MS was employed to analyze the nickel and chromium released in saliva. The mean differences were measured with Wilcoxon, Kruskal Wallis test, and Post-Hoc Mann Whitney test. Differences were considered statistically significant when p-value<0.05. Results: The mean corrosion resistance based on the nickel content released by the new brackets was 99.95%, 99.87%, 87.09%, 90.58%, and 90.26% for groups A, B, C, D, and E, respectively. The mean corrosion resistance based on the nickel content released by the recycled brackets was 99.90%, 99.80%, 98.19%, 89.76%, and 72.82%, respectively. There was a significant difference in corrosion resistance among the 5 groups after recycling by direct flaming and between new and recycled brackets in each group. Conclusion: The corrosion resistance of the brackets in groups A (Ormco), B (GAC), D (S-Ortho), and E (Protect) decreased after thermal recycling by direct flaming. The Ormco brackets had the highest corrosion resistance after thermal recycling by direct faming.

Half-molar sodium-lactate solution has a beneficial effect in patients after coronary artery bypass grafting.

OBJECTIVE: To compare two solutions for fluid resuscitation in post-coronary artery bypass grafting (CABG) surgery patients: Ringer's lactate (RL) versus a new solution containing half-molar sodium-lactate (HL). DESIGN: Prospective randomized open label study. SETTING: The first 12 h post-CABG surgery in an intensive care unit (ICU). PATIENTS: There were 230 patients enrolled in the study: 208 were analyzed, with 109 from the HL group and 99 from the RL group. INTERVENTIONS: Patients received over the first 12 h post-CABG 10 ml kg BW(-1) HL solution in the HL group versus 30 ml kg BW(-1) of RL solution in the RL group. MEASUREMENTS AND RESULTS: Hemodynamic status, body fluid balance and inotrope utilization were compared in the two groups. Post-operative cardiac index increase was significantly higher in HL than in RL (P = 0.02), while mean arterial pressure and other hemodynamic parameters were comparable together with urinary output, indicating similar tissue perfusion in both the groups despite a much lower fluid infusion in the HL group. Therefore, a significant negative fluid balance was achieved in the HL but not in the RL group (-790 +/- 71 vs. +43 +/- 115 mL 12 h(-1), P < 0.0001 for HL and RL, respectively). None of the enrolled patients exhibited side effects related to the treatment. CONCLUSION: Half-molar lactate solution is effective for fluid resuscitation in post-CABG patients. Compared to Ringer's Lactate, its use results in a significantly higher cardiac index with less volume being infused, resulting in a very negative post-operative body fluid balance.

Effect of cardiopulmonary bypass on lactate metabolism.

OBJECTIVE: We have investigated the role of cardiopulmonary bypass on lactate metabolism in patients undergoing uncomplicated surgery for elective coronary artery bypass grafting (CABG). DESIGN: Prospective non-randomized observational study. SETTINGS: National Cardiovascular Center. PATIENTS. Three independent groups were studied: preoperative ( n=20), postoperative with bypass (CPB, n=20) and postoperative without bypass (NO-CPB, n=20). INTERVENTIONS: Lactate metabolism was investigated with the use of an exogenous lactate challenge test (2.5 mmol Na-lactate/kg body weight in 15 min). Blood lactate was sequentially determined after the end of infusion. Lactate clearance and endogenous production were estimated from the area under the curve, and a bi-exponential fitting permitted modeling the lactate-decay into two compartments. MEASUREMENTS AND MAIN RESULTS: Lactate metabolism parameters (basal lactate, clearance, endogenous production and half-lives [HL] I and II) were not different between the NO-CPB and preoperative groups. In the CPB group, as compared to the other two groups, basal lactate and endogenous production were not significantly affected while lactate clearance (CPB: 6.02+/-0.97 versus preoperative: 9.41+/-0.93 and NO-CPB: 9.6+/-0.8 ml/kg per min) and HL-I (CPB: 10.6+/-1.4 versus preoperative: 17.2+/-2.3 and NO-CPB: 18.8+/-2.5 min) were decreased ( p<0.001) and HL-II was increased (CPB: 171+/-41 versus preoperative: 73+/-12 and NO-CPB: 48+/-2.9 min, p<0.01). CONCLUSION: While surgery and anesthesia per se do not seem to alter lactate metabolism, CPB significantly decreased lactate clearance, this effect being possibly related to a mild liver dysfunction even in uncomplicated elective surgery.