Effect of the carbon dioxide 10,600-nm laser and topical fluoride gel application on enamel microstructure and microhardness after acid challenge: an in vitro study

Abstract

The aim of this in-vitro study was to evaluate positive effects of the carbon dioxide laser (CO₂, 10,600 nm) with acidulated phosphate fluoride (APF) gel on enamel acid resistance. Twenty extracted human third molars (40 surfaces) were randomly assigned into four groups: group C, untreated control; group L, CO₂ laser alone group; group F, APF 1.23% fluoride gel; and group FL, APF 1.23% gel and laser. Samples from group L were irradiated with a CO₂ laser for 30s. The parameter settings used were average power, 0.73 W; time on, 100 μs; time off, 40 ms; tip-to-tissue distance, 20 mm; tip diameter 700 μm; and energy density with movements, 5 J/cm². Samples from group F were treated with the APF gel for 4 min, and the gel was washed off with distilled water. The enamel samples from group FL were treated with APF gel for 4 min and then irradiated with the CO₂ laser for 30s without removing the gel. Each enamel sample was placed in 50 ml soft drink (pH = 2.75) for 10 min then rinsed with deionized water and stored in artificial saliva at 37 °C for 1 h. Samples were assessed for Vickers hardness number (VHN) before and after treatments and subjected to SEM analysis. Data were analyzed using a one-way analysis of variance (ANOVA) and Tukey's test (α < 0.05). After the acid challenge, the untreated C group was demineralized to a great extent and the enamel surface was with the lowest mean score of microhardness. The observed VHN in the control (C group) had a mean value of 176.13, the scores in the CO₂ laser group (L group) were with mean value of 238.40, the F group with a mean value of 218.45, and the fluoride-treated and laser-irradiated FL group—with a mean of 268.28 VHN. Paired t test performed to compare groups C, L, F, and FL has shown that group FL has greater resistance to decrease in microhardness of dental enamel (P ≤ 0.05) on exposure to acidic protocol. After the acid challenge, the fluoride-treated and laser-irradiated samples (group FL) showed the least diminution in enamel surface microhardness. The sub-ablative carbon dioxide laser irradiation in combination with fluoride treatment is more effective in protecting enamel surface and resisting demineralization than CO₂ laser irradiation or fluoride alone.

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Breaking paradigms in severe epistaxis: the importance of looking for the S-point

Publication date: Available online 20 January 2018
Source:Brazilian Journal of Otorhinolaryngology
Author(s): Eduardo Macoto Kosugi, Leonardo Balsalobre, João Mangussi Gomes, Miguel Soares Tepedino, Daniel Marcus San da Silva, Erika Mucciolo Cabernite, Diego Hermann, Aldo Cassol Stamm
IntroductionSince the introduction of nasal endoscopy into the field of Otorhinolaryngology, the treatment paradigm for cases of severe epistaxis has shifted toward early and precise identification of the bleeding site. Although severe epistaxis is usually considered to arise from posterior bleeding, an arterial vascular pedicle in the superior portion of the nasal septum, around the middle turbinate axilla projection, frequently has been observed. That vascular pedicle was named the S-point.ObjectiveThe aim of this study was to describe the S-point and report cases of severe epistaxis originating from it.MethodsA retrospective case series study was conducted. Nine patients with spontaneous severe epistaxis, where the S-point was identified as the source of bleeding, were treated between March 2016 and March 2017.ResultsMale predominance (77.8%) with age average of 59.3 years old were reported. Most cases presented comorbidities (88.9%) and were not taking acetylsalicylic acid (66.7%). A predominance of left sided involvement (55.6%) anteroposterior bleeding being the principal initial presentation (77.8%) was seen. Six patients (66.7%) presented with hemoglobin levels below 10g/dL, and four (44.4%) required blood transfusion. Cauterization of S-point was performed in all patients, with complete resolution of bleeding. No patient experienced recurrence of severe epistaxis.ConclusionThe S-point, a novel source of spontaneous severe epistaxis, is reported, and its cauterization was effective and safe. Otolaryngologists must actively seek this site of bleeding in cases of severe epistaxis.



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Intratidal Analysis of Intraoperative Respiratory System Mechanics: Keep it Simple

No abstract available

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The Syringe Driver: Continuous Subcutaneous Infusions in Palliative Care, 4th ed.

No abstract available

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Alkalinized Lidocaine Preloaded Endotracheal Tube Cuffs Reduce Emergence Cough After Brief Surgery: A Prospective Randomized Trial

BACKGROUND: Alkalinized lidocaine in the endotracheal tube (ETT) cuff decreases the incidence of cough and throat pain on emergence after surgery lasting more than 2 hours. However, alkalinized lidocaine needs 60–120 minutes to cross the ETT cuff membrane; therefore, its usefulness in shorter duration surgery is unknown. This prospective double-blind randomized controlled trial tested the hypothesis that alkalinized lidocaine would reduce the incidence of emergence cough after surgeries lasting 90 minutes before intubation with either 2 mL of 2% lidocaine and 8 mL of 8.4% bicarbonate (group AL) or 10 mL of normal saline (group S). Cuffs were emptied immediately before intubation. After intubation, either 2 mL of 2% lidocaine (AL) or 2 mL of saline (S) were injected into the cuff. Additional 8.4% bicarbonate (AL) or saline (S) was injected into the cuff until there was no air leak. Anesthesia was maintained using desflurane, rocuronium, and either fentanyl or sufentanil to maintain vital signs within 20% of baseline values. Opioids administered in prophylaxis of extubation cough were proscribed. A standardized "no touch" emergence technique was used. A blinded assessor noted any cough above 0.2 minimum alveolar concentration (MAC) of expired desflurane. At 0.2 MAC, once every 30 seconds, the patient was instructed to open his eyes and extubation occurred once a directed response was noted. RESULTS: A total of 213 patients were randomized and 100 patients in each group completed the experimental protocol. The incidence of extubation cough in group AL was 12%, significantly lower (1-sided P = .045) than the 22% incidence in group S. The 1-tailed risk ratio for cough in group AL was 0.55 (0–0.94, P = .045). Total amount of opioids administered (P = .194), ETT cuff preloading times (P = .259), and extubation times (P = .331) were not significantly different between groups. The average duration of surgery was 59 ± 28 minutes in group AL and 52 ± 29 minutes in group S (P = .057). CONCLUSIONS: Alkalinized lidocaine in the ETT cuff significantly decreased general anesthesia emergence cough after surgeries with an average duration of slightly

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“Mirror, Mirror on the Wall”: Learning From Reflections on Quality

No abstract available

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A Novel Approach to Synthesize the Evidence on Analgesic Adjuvants for Postoperative Pain

No abstract available

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