Flexural Strength of an Indirect Composite Modified with Single-Wall Carbon Nanotubes

OBJECTIVES

 The low resistance to fracture has limited the use of indirect composite resins for dental restorations, particularly in regions that are exposed to strong occlusal forces. To overcome this issue, different types of reinforcement for composites have been proposed, one of which is carbon nanotubes (CNTs). The aim of this study was to evaluate the flexural resistance of one commercial indirect composite resin (Sinfony, 3M/ESPE) after incorporation of single-wall carbon nanotubes (SWCNTs; Sigma-Aldrich, Inc., St. Louis, Missouri, United States) with or without the silanization form.

MATERIALS AND METHODS

 Specimens of composite resin were fabricated in a Teflon mold. The composite resin was prepared according to the manufacturer's instructions (n = 10 for each group), with SWCNTs in three concentrations.

STATISTICAL ANALYSIS

 The SWCNTs and SWCNT/SiO2-ATES specimens were evaluated by transmission electron microscopy, and a flexural test was conducted according to the ISO 4049/2009. Flexural strength data in MPa were submitted to one-way ANOVA following Tukey (p < 0.05).

RESULTS

 The SWCNTs did not improve the flexural strength of indirect composite resin when compared with the control, independent of the concentration added (p > 0.05). However, when SWCNTs and SWCNTs/SiO2-ATES were compared, the SWCNTs/SiO2-ATES showed higher values than the three concentrations of SWCNTs (p < 0.05).

CONCLUSION

 The silanization process improves the SWCNTs strength proprieties, but the modification of chemical bonding between SWCNT and SWCNT/SiO2-ATES modified resins, in different concentrations, did not improve the composite resin flexural strength.

Oral pigmentation as an adverse effect of chloroquine and hydroxychloroquine use: A scoping review

BACKGROUND

Chloroquine and hydroxychloroquine are 2 medications used to treat some systemic diseases.

OBJECTIVE

The aim of this scoping review was to assess the occurrence of oral pigmentation induced by chloroquine or hydroxychloroquine and to understand the pathogenic mechanism behind this phenomenon.

METHODS

The review was performed according to the list of PRISMA SrC recommendations and the JBI Manual for Evidence Synthesis for Scoping Reviews. MEDLINE (PubMed), Scopus, EMBASE, SciELO, Web of Science, Lilacs, and LIVIVO were primary sources, and "gray literature" was searched in OpenThesis and Open Access Thesis and Dissertations (OATD). Studies that screened the occurrence of oral pigmentation associated to the use of chloroquine or hydroxychloroquine were considered eligible. No restrictions of year and language of publication were applied. Study selection and data extraction were performed by 2 independent reviewers. The risk of bias was assessed through the JBI tool, depending on the design of the selected studies.

RESULTS

The initial search resulted in 2238 studies, of which 19 were eligible. Sixteen studies were case reports, 2 had case-control design and 1 was cross-sectional. Throughout the studies, 44 cases of oral pigmentation were reported. The hard palate was the anatomic region most affected with pigmentation (66%). According to the case reports, most of the lesions (44%) were bluish-gray. The minimum time from the beginning of treatment (chloroquine or hydroxychloroquine) to the occurrence of pigmentation was 6 months. The mean treatment time with the medications was 4.9 years, and the mean drug dosage was 244 mg. Most of the studies (63.1%) had low risk of bias (high methodological quality).

CONCLUSIONS

The outcomes of this study suggest that hyperpigmentation depend on drug dosage and treatment length. Hyperpigmentation was detected after a long period of treatment with chloroquine or hydroxychloroquine.

Preemptive use of intravenous ibuprofen to reduce postoperative pain after lower third molar surgery: a systematic review of randomized controlled trials

This study aimed to systematically review the literature to assess the effect of preemptive intravenous ibuprofen on pain reduction after lower third molar surgery. Nine databases (PubMed, Scopus, LILACS, SciELO, Embase, Web of Science, Cochrane, Open Gray, and Open Thesis) were used as sources of research, including "grey literature." The protocol was registered in PROSPERO. Only randomized clinical trials evaluating the effects of preemptive intravenous ibuprofen on pain during and immediately after the extraction of lower third molars were included, without restrictions of year and language. Two reviewers independently performed the study selection, data extraction, and assessment of the risk of bias. The "Joanna Briggs Institute for Randomized Controlled Trials" tool was used to assess the risk of bias. Each study was categorized according to the percentage of positive responses to the questions corresponding to the assessment instrument. The results were measured narratively/descriptively. The initial search resulted in 3,257 records, of which only three studies (n=150 participants) met the eligibility criteria and were included in the qualitative analysis. All studies were published in 2019. The risk of bias ranged from low to moderate. Two studies found significant pain reduction within 48 h after the procedure. In conclusion, the use of preemptive intravenous ibuprofen for extracting third molars reduces pain and analgesic consumption after the surgical procedure.

Combination of toothbrushing and chlorhexidine compared with exclusive use of chlorhexidine to reduce the risk of ventilator-associated pneumonia: A systematic review with meta-analysis

This study aimed to compare the effectiveness of 0.12% chlorhexidine alone and 0.12% chlorhexidine in combination with toothbrushing to prevent ventilator-associated pneumonia (VAP) in mechanically ventilated patients. The Embase, Latin American and Caribbean Health Science Literature, PubMed, Scientific Electronic Library Online, Scopus, LIVIVO, Web of Science, Cochrane Library, OpenThesis, and Open Access Thesis and Dissertations databases were used. Only randomized controlled trials without restrictions on the year or language of publication were included. Two reviewers assessed the risk of bias using the Joanna Briggs Institute Critical Appraisal Tool. A meta-analysis using a random-effects model estimated the combined relative risk (RR). The Grading of Recommendations, Assessment, Development and Evaluations approach was used to assess the certainty of the evidence. Initially, 2,337 studies were identified, of which 4 were considered in the systematic review and 3 in the meta-analysis (total sample: 796 patients). The studies were published between 2009 and 2017. All eligible studies had a low risk of bias. The meta-analysis revealed that the risk of VAP was 24% lower in patients receiving chlorhexidine combined with toothbrushing than in those receiving chlorhexidine alone (RR: 0.76; 95% confidence interval: 0.55-1.06), with moderate certainty of evidence and without statistical significance. In conclusion, considering the limitations of this study, a standard protocol for the prevention of VAP is not yet recommended. More studies with larger sample sizes are needed to draw strong conclusions. However, considering that toothbrushing is a simple intervention, it should be a common practice in mechanically ventilated patients, especially among patients with coronavirus disease.