Efficacy of GLUMA for the Treatment of Dentin Hypersensitivity Compared to Lasers: A Systematic Review.

OBJECTIVE: Dentin hypersensitivity (DH) is characterized by a short, sharp pain in response to a thermal or tactile stimulus. The application of desensitizing agents such as GLUMA and laser is a non-invasive and safe approach to decrease sensitivity. The evidence for the efficacy of GLUMA desensitizer compared to laser desensitization in patients with DH was evaluated for 6 months. DESIGN: In March 2022, an electronic search of PubMed, Scopus, and Web of Science databases was conducted. Articles published in English that compared GLUMA and laser in the treatment of DH with a follow-up of 6 months or more were included. Randomized, non-randomized controlled trials, and clinical trials were included. Risk of bias assessment tools developed by the Cochrane collaboration ROB 2 and ROBINS-I were used to assess the quality of studies. The GRADE assessment method was used to assess the certainty of evidence. RESULTS: About 36 studies were identified in the search results. After applying the predefined eligibility criteria, eight studies with 205 participants and 894 sites were included in this review. Of the eight studies, four were judged to be at high risk of bias, three had some concerns, and one had a serious risk of bias. The certainty of the evidence was graded as low. CONCLUSION: Based on limited evidence, GLUMA and laser appear to be equally effective in providing relief from DH. GLUMA showed an immediate effect and provided pain relief. Over the course of a week, laser showed long-term stable results. GLUMA is effective in providing immediate relief.

pH-Sensitive Polymer-Based Carriers as a Useful Approach for Oral Delivery of Therapeutic Protein: A Review.

There are many proteins and enzymes in the human body, and their dysfunction can lead to the emergence of a disease. The use of proteins as a drug is common in various diseases such as diabetes. Proteins are hydrophilic molecules whose spatial structure is critical to their correct function. There are different ways for the administration of proteins. Protein structures are degraded by gastric acid and enzymes in the gastrointestinal tract and have a slight ability to permeate from the gastrointestinal epithelium due to their large hydrophilic nature. Therefore, their oral use has limitations. Since the oral route for the administration of drugs is one of the best and easiest routes for patients, many studies have been done to increase the stability, penetration, and ultimately, the bioavailability of proteins through oral administration. One of the studied strategies for oral delivery of protein is the use of pH-sensitive polymer-based carriers. These carriers use different pH-sensitive polymers, such as eudragit®, chitosan, dextran, and alginate. The use of pH-sensitive polymer- based carriers by protecting the protein from stomach acid (low pH) and degrading enzymes, increasing permeability and maintaining the spatial structure of the protein, leads to increased bioavailability. In this review, we focus on the various polymers used to prepare pH-sensitive polymer- based carriers for the oral delivery of proteins.

A randomized clinical trial of dentin hypersensitivity reduction over one month after a single topical application of comparable materials.

Dentinal hypersensitivity (DH) is a condition that causes patient discomfort. To evaluate the clinical efficacy of Gluma, fluoride varnish and Tetric N-Bond self-etch system in relieving DH immediately and over 30 days following a single topical application. The present randomized clinical trial was conducted on 55 patients with an age range 20-49 years. 70 teeth in total were incorporated and randomly assigned to the three groups. Parameters examined were: Tactile, air blast, and cold stimuli. VAS was used to assess tactile stimulus whereas the Schiff Cold Scale for air blast and cold stimuli. DH was evaluated immediately, at two weeks and 1 month follow up. Gluma showed a statistically significant reduction in DH scores over other materials. It was concluded that Gluma have statistically significant results over other materials in relieving DH immediately and over 30 days following a single topical application.Trial Registration: Clinical Trials.gov Identifier: NCT04351412, King Abdulaziz University Protocol Record 129-09-19. Registered 17 April 2020 - Retrospectively registered. http://ClinicalTrials.gov/NCT04351412 .

Mitochondrial Dysfunction Associates With Acute T Lymphocytopenia and Impaired Functionality in COVID-19 Patients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in rapid T lymphocytopenia and functional impairment of T cells. The underlying mechanism, however, remains incompletely understood. In this study, we focused on characterizing the phenotype and kinetics of T-cell subsets with mitochondrial dysfunction (MD) by multicolor flow cytometry and investigating the association between MD and T-cell functionality. While 73.9% of study subjects displayed clinical lymphocytopenia upon hospital admission, a significant reduction of CD4 or CD8 T-cell frequency was found in all asymptomatic, symptomatic, and convalescent cases. CD4 and CD8 T cells with increased MD were found in both asymptomatic and symptomatic patients within the first week of symptom onset. Lower proportion of memory CD8 T cell with MD was found in severe patients than in mild ones at the stage of disease progression. Critically, the frequency of T cells with MD in symptomatic patients was preferentially associated with CD4 T-cell loss and CD8 T-cell hyperactivation, respectively. Patients bearing effector memory CD4 and CD8 T cells with the phenotype of high MD exhibited poorer T-cell responses upon either phorbol 12-myristate-13-acetate (PMA)/ionomycin or SARS-CoV-2 peptide stimulation than those with low MD. Our findings demonstrated an MD-associated mechanism underlying SARS-CoV-2-induced T lymphocytopenia and functional impairment during the acute phase of infection.

Colon-Targeted Therapy of Tacrolimus (FK506) in the Treatment of Experimentally Induced Colitis.

BACKGROUND/AIMS: Inflammatory bowel disease is a chronic or remitting/relapsing intestinal inflammation, which comprises Crohn's disease and ulcerative colitis (UC). Severe UC is a life-threatening condition that requires corticosteroids (CS) as a first-line rescue therapy. Some patients are refractory to CS and may require alternative immunosuppressive therapy. Oral tacrolimus (FK506), an immunosuppressive agent, has been reported to be effective in the management of severe refractory UC, but it can cause serious adverse effects. This work aims to study the effect of tacrolimus delivered by a colon-targeted delivery system (CTDS) in a dextran sulfate sodium (DSS)-induced animal model of colitis. MATERIALS AND METHODS: We developed and evaluated an oral CTDS of tacrolimus (FK506) loaded pH-dependent polymeric microspheres, composed of Eudragit® S100 as a pH-sensitive polymer using the oil-in-water emulsion method. The physicochemical properties and drug release profiles of these microparticles in gastrointestinal tract (GIT) conditions were examined. A DSS-induced colitis rat model was used to evaluate the potential remedial and in vivo distribution of microspheres. RESULTS: The pH-microspheres prevented a burst drug release in acidic pH conditions and showed sustained release at a colonic pH. The in vivo distribution study in the rat GIT demonstrated that pH-microspheres were successfully delivered to the inflamed colon. Moreover, it also demonstrated a significant decrease of disease activity and expression of proinflammatory cytokines, such as tumor necrosis factor α, interleukin-1ß (IL-1ß), and IL-6, and minimized the histological and morphometric changes. CONCLUSION: The results confirmed the efficacy of tacrolimus (FK506) CTDs in the management of DSS-induced colitis.

Synthesis and in vitro cytotoxicity evaluation of star-shaped polymethacrylic conjugates with methotrexate or acitretin as potential antipsoriatic prodrugs.

Water-soluble polymer-drug conjugates were obtained and analyzed towards their potential use as prodrugs for two hydrophobic antipsoriatic agents, including methotrexate (MTX) and acitretin (AC). The conjugation efficacy of MTX decreased with a decreasing molar ratio of N,N-dimethylaminoethyl methacrylate (DMAEMA) repeating units in the polymethacrylic chains. Cytotoxicity of positively charged (from +5 to +10 mV) nano- and microparticles (3-1500 nm in DMEM at 37 °C) were estimated by in vitro MTT and Annexin-V apoptosis assays on Me45, NHDF, HaCaT and BEAS-2B cell lines. Further, cell cycle analysis revealed arrest in G0/G1 phase in melanoma cells, while neither apoptosis induction nor cell cycle arrest occurred in normal epidermal and epithelial cells. Tested conjugates displayed a novel cytostatic effect in Me45 cells and a pro-apoptotic effect in HaCaT cells. Epithelial BEAS-2B cells were the most sensitive to the tested conjugates and responded via induction of necrosis. Cell line models allowed for characterization of the biologically relevant potential action of pro-drugs. Additionally, a skin in vitro evaluation assay provided the first known evidence of side-effect reduction with pro-drug use. Histological examinations confirmed the lack of negative effects of conjugates on the skin and showed no irritating properties.

Effect of erosive and abrasive stress on sealing ability of different desensitizers: In-vitro study.

This in vitro study examined the sealing ability of different desensitizing agents under a chemo-mechanical stress condition. For the study, a total of 144 extracted, caries-free human third molars were used to produce 1 mm-thick dentin discs. The specimens were divided randomly into four groups: Superseal (SS), Gluma (GL), Gluma Self-etch (GS), and Tooth Coat (TC). For each group, the permeability was measured before and after applying the desensitizer, after being exposed to Coca Cola for 5 minutes, and after 3150 strokes of a brushing abrasion. The decrease in permeability after the erosive and abrasive stress was analyzed by ANOVA and Tukey post hoc test. As a result, the dentin permeability decreased significantly for all desensitizers immediately after application (p < 0.05). SS and GS showed a significant difference in permeability reduction observed immediately after application and after acid action with Coca Cola (p < 0.05). After brushing abrasion, the permeability reduction decreased significantly for all desensitizers tested in this study (p < 0.05). TC showed the largest decrease in dentinal permeability compared to that of the other desensitizers and the differences were significant after brushing abrasion (p < 0.05). All tested desensitizers were effective in reducing dentin permeability. The behavioral characteristics under erosive and abrasive stress varied according to the products used. TC exhibited excellent sealing ability among the other desensitizers.

Effect of free and nano-encapsulated curcumin on treatment and energetic metabolism of gerbils infected by Listeria monocytogenes.

Bacterial infections require special care since the indiscriminate use of antibiotics to treat them has been linked to the emergence of resistant strains. In this sense, phytoterapeutic alternatives such as curcumin and its nanocapsules have emerged as a promising supplement in optimizing availability of bioactives and reducing the development of antimicrobial resistance. Thus, the aim of this study was to verify the effects of pure and nanoencapsulated curcumin in the treatment of experimental listeriosis in gerbils regarding many aspects including antibacterial effect, antioxidant mechanisms involved and the energetic metabolism. Four groups were used containing 6 animals each: T0 (control), T1 (infected), T2 (infected and treated with free curcumin - dose of 30 mg/kg/day) and T3 (infected and treated with nanocapsules containing curcumin - a dose of 3 mg/kg/day). Treated animals received curcumin for 6 consecutive days starting 24 h after Listeria monocytogenes infection. All animals were euthanized on the 12th day after L. monocytogenes infection. Quantitative polymerase chain reaction (qPCR) identified L. monocytogenes DNA in the spleens of all animals of the T1 group, as well as T2 (2 out of 6) and T3 (5 out of 6). The weight of the spleens confirmed the infection, since it was larger in the T1 group, differing statistically from T0, and similarly to T2 and T3. Hepatic histopathological examination showed mild infiltration of neutrophils and macrophages, except for the T3 group (only 1/6). In the liver, the pyruvate kinase activity was higher in T1 and T2 compared to T0 and T3. The adenylate kinase activity did not differ between groups. The Na+/K+ATPase activity was lower in T1 group compared to T0 and T3. Lipoperoxidation was lower in the T3 group compared to groups T0, T1 and T2. The antioxidant capacity against peroxyl radicals was higher in T1, T2 and T3 groups compared to T0. In conclusion, free curcumin showed potent antibacterial effects; however, the nanoencapsulated form was able to minimize the effects caused by L. monocytogenes regarding tissue injury, changes on enzymes of the energetic metabolism, in addition to an antioxidant effect against lipoperoxidation.

Twenty-four-month clinical performance of different universal adhesives in etch-and-rinse, selective etching and self-etch application modes in NCCL - a randomized controlled clinical trial.

OBJECTIVE: The aim of this randomized, controlled, prospective clinical trial was to evaluate the performances of two different universal adhesives and one etch-rinse adhesive for restoration of non-carious cervical lesions (NCCLs). MATERIAL AND METHODS: Twenty patients with at least seven NCCLs were enrolled. Lesions were divided into seven groups according to adhesive systems and application modes: GSE: GLUMA Universal-self-etch, GSL: GLUMA Universal-selective etching, GER: GLUMA Universal-etch-and-rinse, ASE: All-Bond Universal-self-etch, ASL: All-Bond Universal-selective etching, AER: All-Bond Universal-etch-and-rinse, SBE (Control): Single Bond2-etch-and-rinse. A total of 155 NCCLs were restored with a nano hybrid composite (Tetric N-Ceram). Restorations were scored with regard to retention, marginal discoloration, marginal adaptation, recurrent caries and post-operative sensitivity using modified United States Public Health Service (USPHS) criteria after one week, 6, 12 and 24 months. Statistical evaluations were performed using Chi-square tests (p=0.05). RESULTS: The recall rate was 81.9% after the 24-month follow-up. The cumulative retention rates for self-etch groups (GSE: 72.2%, ASE:75%) were significantly lower than other experimental groups (GSL: 93.7%, GER: 100%, ASL: 94.1%, AER: 100%, SBE: 100%) at the 24-month follow-up (p<0.05). Regarding marginal adaptation and marginal discoloration, GSE and ASE groups demonstrated more bravo scores after 6 and 12-month observations but differences were not significant (p>0.05). Only one restoration from ASL group demonstrated post-operative sensitivity at 6 and 12-month observations. No secondary caries was observed on the restorations at any recall. At the end of 24-month observations, no significant differences were detected among groups regarding any of the criteria assessed, except retention. CONCLUSION: GLUMA Universal and All-Bond Universal showed better results in etch-and-rinse and selective etching mode compared to the self-etch mode regarding retention. Etch-and-rinse and selective etching application modes of the current universal adhesives tended to provide better clinical outcomes considering the criteria evaluated at the end of 24-month evaluation.

Print-based self-help interventions for smoking cessation.

BACKGROUND: Many smokers give up smoking on their own, but materials that provide a structured programme for smokers to follow may increase the number who quit successfully. OBJECTIVES: The aims of this review were to determine the effectiveness of different forms of print-based self-help materials that provide a structured programme for smokers to follow, compared with no treatment and with other minimal contact strategies, and to determine the comparative effectiveness of different components and characteristics of print-based self-help, such as computer-generated feedback, additional materials, tailoring of materials to individuals, and targeting of materials at specific groups. SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group Trials Register, ClinicalTrials.gov, and the International Clinical Trials Registry Platform (ICTRP). The date of the most recent search was March 2018. SELECTION CRITERIA: We included randomised trials of smoking cessation with follow-up of at least six months, where at least one arm tested print-based materials providing self-help compared with minimal print-based self-help (such as a short leaflet) or a lower-intensity control. We defined 'self-help' as structured programming for smokers trying to quit without intensive contact with a therapist. DATA COLLECTION AND ANALYSIS: We extracted data in accordance with standard methodological procedures set out by Cochrane. The main outcome measure was abstinence from smoking after at least six months' follow-up in people smoking at baseline. We used the most rigorous definition of abstinence in each study and biochemically validated rates when available. Where appropriate, we performed meta-analysis using a random-effects model. MAIN RESULTS: We identified 75 studies that met our inclusion criteria. Many study reports did not include sufficient detail to allow judgement of risk of bias for some domains. We judged 30 studies (40%) to be at high risk of bias for one or more domains.Thirty-five studies evaluated the effects of standard, non-tailored self-help materials. Eleven studies compared self-help materials alone with no intervention and found a small effect in favour of the intervention (n = 13,241; risk ratio (RR) 1.19, 95% confidence interval (CI) 1.03 to 1.37; I² = 0%). We judged the evidence to be of moderate certainty in accordance with GRADE, downgraded for indirect relevance to populations in low- and middle-income countries because evidence for this comparison came from studies conducted solely in high-income countries and there is reason to believe the intervention might work differently in low- and middle-income countries. This analysis excluded two studies by the same author team with strongly positive outcomes that were clear outliers and introduced significant heterogeneity. Six further studies of structured self-help compared with brief leaflets did not show evidence of an effect of self-help materials on smoking cessation (n = 7023; RR 0.87, 95% CI 0.71 to 1.07; I² = 21%). We found evidence of benefit from standard self-help materials when there was brief contact that did not include smoking cessation advice (4 studies; n = 2822; RR 1.39, 95% CI 1.03 to 1.88; I² = 0%), but not when self-help was provided as an adjunct to face-to-face smoking cessation advice for all participants (11 studies; n = 5365; RR 0.99, 95% CI 0.76 to 1.28; I² = 32%).Thirty-two studies tested materials tailored for the characteristics of individual smokers, with controls receiving no materials, or stage-matched or non-tailored materials. Most of these studies used more than one mailing. Pooling studies that compared tailored self-help with no self-help, either on its own or compared with advice, or as an adjunct to advice, showed a benefit of providing tailored self-help interventions (12 studies; n = 19,190; RR 1.34, 95% CI 1.20 to 1.49; I² = 0%) with little evidence of difference between subgroups (10 studies compared tailored with no materials, n = 14,359; RR 1.34, 95% CI 1.19 to 1.51; I² = 0%; two studies compared tailored materials with brief advice, n = 2992; RR 1.13, 95% CI 0.86 to 1.49; I² = 0%; and two studies evaluated tailored materials as an adjunct to brief advice, n = 1839; RR 1.72, 95% CI 1.17 to 2.53; I² = 10%). When studies compared tailored self-help with non-tailored self-help, results favoured tailored interventions when the tailored interventions involved more mailings than the non-tailored interventions (9 studies; n = 14,166; RR 1.42, 95% CI 1.20 to 1.68; I² = 0%), but not when the two conditions were contact-matched (10 studies; n = 11,024; RR 1.07, 95% CI 0.89 to 1.30; I² = 50%). We judged the evidence to be of moderate certainty in accordance with GRADE, downgraded for risk of bias.Five studies evaluated self-help materials as an adjunct to nicotine replacement therapy; pooling three of these provided no evidence of additional benefit (n = 1769; RR 1.05, 95% CI 0.86 to 1.30; I² = 0%). Four studies evaluating additional written materials favoured the intervention, but the lower confidence interval crossed the line of no effect (RR 1.20, 95% CI 0.91 to 1.58; I² = 73%). A small number of other studies did not detect benefit from using targeted materials, or find differences between different self-help programmes. AUTHORS' CONCLUSIONS: Moderate-certainty evidence shows that when no other support is available, written self-help materials help more people to stop smoking than no intervention. When people receive advice from a health professional or are using nicotine replacement therapy, there is no evidence that self-help materials add to their effect. However, small benefits cannot be excluded. Moderate-certainty evidence shows that self-help materials that use data from participants to tailor the nature of the advice or support given are more effective than no intervention. However, when tailored self-help materials, which typically involve repeated assessment and mailing, were compared with untailored materials delivered similarly, there was no evidence of benefit.Available evidence tested self-help interventions in high-income countries, where more intensive support is often available. Further research is needed to investigate effects of these interventions in low- and middle-income countries, where more intensive support may not be available.

Fluoride varnish versus glutaraldehyde for hypersensitive teeth: a randomized controlled trial, meta-analysis and trial sequential analysis.

OBJECTIVE: Reports indicate Gluma and Duraphat are commonly used in-office agents to treat hypersensitive teeth. Considering this, the aim of this paper is to compare Gluma and Duraphat using a randomized controlled trial, meta-analysis collating evidences from previous studies and trial sequential analysis. MATERIALS AND METHODS: Thirty-eight participants were randomized. Hypersensitivity and visual analog scale (VAS) scores were recorded at baseline, 5 min and 7 days. Oral health-related quality of life (OHIP) questionnaire was administered at baseline and 7 days. Statistical analysis was performed to identify significant differences between the variables. For the meta-analysis, electronic data bases were searched and eligible data was extracted and analysed using RevMan 5.0. Trial sequential analysis was performed using O'Brien-Fleming boundary approach for the primary outcome. RESULTS: Both agents caused significant reduction in hypersensitivity and VAS score at 5 min and 7 days in the randomized trial with no superiority. The quality of life significantly improved in patients treated with both the agents. Four studies including the present trial in meta-analysis and trial sequential analysis indicated that Gluma produced significant reduction in VAS scores at 7 days. CONCLUSION: Gluma produces significant reduction in hypersensitivity at 7 days post treatment compared with Duraphat. There is definite lack of evidence on the long-term effect of these agents. CLINICAL RELEVANCE: This paper provides strong evidence on the use of Gluma for hypersensitive teeth. This also is a way forward to future research on long-term effects, adverse effects and cost-effectiveness studies.

Biological and Mechanical Evaluation of Novel Prototype Dental Composites.

The breakdown of the polymeric component of contemporary composite dental restorative materials compromises their longevity, while leachable compounds from these materials have cellular consequences. Thus, a new generation of composite materials needed to be designed to have a longer service life and ensure that any leachable compounds are not harmful to appropriate cell lines. To accomplish this, we have developed concurrent thiol-ene-based polymerization and allyl sulfide-based addition-fragmentation chain transfer chemistries to afford cross-linked polymeric resins that demonstrate low shrinkage and low shrinkage stress. In the past, the filler used in dental composites mainly consisted of glass, which is biologically inert. In several of our prototype composites, we introduced fluorapatite (FA) crystals, which resemble enamel crystals and are bioactive. These novel prototype composites were benchmarked against similarly filled methacrylate-based bisphenol A diglycidyl ether dimethacrylate / triethylene glycol dimethacrylate (bisGMA/TEGDMA) composite for their cytotoxicity, mechanical properties, biofilm formation, and fluoride release. The leachables at pH 7 from all the composites were nontoxic to dental pulp stem cells. There was a trend toward an increase in total toughness of the glass-only-filled prototype composites as compared with the similarly filled bisGMA/TEGDMA composite. Other mechanical properties of the glass-only-filled prototype composites were comparable to the similarly filled bisGMA/TEGDMA composite. Incorporation of the FA reduced the mechanical properties of the prototype and bisGMA/TEGDMA composite. Biofilm mass and colony-forming units per milliliter were reduced on the glass-only-filled prototype composites as compared with the glass-only-filled bisGMA/TEGDMA composite and were significantly reduced by the addition of FA to all composites. Fluoride release at pH 7 was greatest after 24 h for the bisGMA/TEGDMA glass + FA composite as compared with the similarly filled prototypes, but overall the F- release was marginal and not at a concentration to affect bacterial metabolism.

Twenty-four-month clinical performance of different universal adhesives in etch-and-rinse, selective etching and self-etch application modes in NCCL - a randomized controlled clinical trial

Abstract Objective The aim of this randomized, controlled, prospective clinical trial was to evaluate the performances of two different universal adhesives and one etch-rinse adhesive for restoration of non-carious cervical lesions (NCCLs). Material and Methods Twenty patients with at least seven NCCLs were enrolled. Lesions were divided into seven groups according to adhesive systems and application modes: GSE: GLUMA Universal-self-etch, GSL: GLUMA Universal-selective etching, GER: GLUMA Universal-etch-and-rinse, ASE: All-Bond Universal-self-etch, ASL: All-Bond Universal-selective etching, AER: All-Bond Universal-etch-and-rinse, SBE (Control): Single Bond2-etch-and-rinse. A total of 155 NCCLs were restored with a nano hybrid composite (Tetric N-Ceram). Restorations were scored with regard to retention, marginal discoloration, marginal adaptation, recurrent caries and post-operative sensitivity using modified United States Public Health Service (USPHS) criteria after one week, 6, 12 and 24 months. Statistical evaluations were performed using Chi-square tests (p=0.05). Results The recall rate was 81.9% after the 24-month follow-up. The cumulative retention rates for self-etch groups (GSE: 72.2%, ASE:75%) were significantly lower than other experimental groups (GSL: 93.7%, GER: 100%, ASL: 94.1%, AER: 100%, SBE: 100%) at the 24-month follow-up (p<0.05). Regarding marginal adaptation and marginal discoloration, GSE and ASE groups demonstrated more bravo scores after 6 and 12-month observations but differences were not significant (p>0.05). Only one restoration from ASL group demonstrated post-operative sensitivity at 6 and 12-month observations. No secondary caries was observed on the restorations at any recall. At the end of 24-month observations, no significant differences were detected among groups regarding any of the criteria assessed, except retention. Conclusion GLUMA Universal and All-Bond Universal showed better results in etch-and-rinse and selective etching mode compared to the self-etch mode regarding retention. Etch-and-rinse and selective etching application modes of the current universal adhesives tended to provide better clinical outcomes considering the criteria evaluated at the end of 24-month evaluation.

Chemical and Mechanical Properties of Experimental Dental Composites as a Function of Formulation and Postcuring Thermal Treatment.

This study evaluated the influence of formulation and thermal treatment on the degree of conversion, fracture toughness, flexural strength, and elastic modulus of experimental composites. Six composites were analyzed at BisGMA : TEGDMA molar ratios of 1 : 1 and 7 : 3 with filler at 30, 50, and 70 wt%. The degree of conversion was analyzed by Fourier transform infrared spectroscopy, fracture toughness was measured using the single-edge notched beam, and flexural strength and elastic modulus were measured with the 3-point bend test. For all tests, one-half of the specimens received thermal treatment at 170°C for 10 min. Data were analyzed by the Kruskal-Wallis or ANOVA/Tukey's test (α = 5%). The 1 : 1 BisGMA : TEGDMA ratio showed higher properties than the 7 : 3 ratio. Although the material with 70% filler had a conversion lower than the one with 50%, it showed higher mechanical properties. The thermal treatment improved all properties in all materials. Therefore, the use of an equimolar ratio of BisGMA : TEGDMA can be paired with 70 wt% filler to design dental composites that possess increased advantageous physical and chemical properties. Furthermore, the simple and low-cost method of thermal treatment proposed for use in clinical dentistry has been shown to effectively improve the properties of all evaluated materials.

Eighteen-month Clinical Study of Universal Adhesives in Noncarious Cervical Lesions.

OBJECTIVE: To evaluate the clinical performance of Scotchbond Universal (3M Oral Care) and Prime & Bond Elect (Dentsply Sirona) in the restoration of noncarious cervical lesions (NCCLs). METHODS AND MATERIALS: This was a randomized controlled clinical trial involving 63 subjects. Two hundred and three NCCLs were restored using Scotchbond Universal and Prime & Bond Elect using both an etch-and-rinse and a self-etch technique. Lesions were notch-shaped NCCLs, and the restorations were placed without any mechanical retention. Restorations were finished immediately after placement and scored with regard to retention, marginal discoloration, marginal adaptation, and secondary caries. Similar assessment of the restorations was performed 18 months after placement. Logistic regression was performed for each outcome separately with a compound symmetric variance-covariance structure assumed to consider a correlation of restorations within subjects. All analyses were conducted using SAS version 9.4 (SAS Inc). RESULTS: One hundred and fifty-eight teeth (77.8% of the restorations placed) in 46 subjects (73% of subjects enrolled) were available for the 18-month follow-up. A statistically significant difference was reached only for the comparison Scotchbond Universal/self-etch (SU_SE) and Prime & Bond Elect/etch-and-rinse (PBE_E&R) groups ( p=0.01), where a restoration with SU_SE was 66% less likely to maintain a score of Alpha for marginal discoloration than a restoration performed with PBE_E&R. CONCLUSIONS: Scotchbond Universal and Prime & Bond Elect presented acceptable clinical performance after 18 months of clinical service. However, Scotchbond Universal, when applied with a self-etch approach, did demonstrate a relatively high level of marginal discoloration when compared to the other groups.

Preventive Use of a Resin-based Desensitizer Containing Glutaraldehyde on Tooth Sensitivity Caused by In-office Bleaching: A Randomized, Single-blind Clinical Trial.

OBJECTIVE: To evaluate the risk and intensity of bleaching-induced tooth sensitivity (TS) after in-office bleaching following topical application of a resin-based glutaraldehyde desensitizer. METHODS: Thirty-three patients were randomly assigned to the experimental (Gluma Desensitizer Liquid, Heraeus Kulzer, Hanau, Germany) and placebo groups. The placebo or Gluma Desensitizer Liquid was applied for one minute prior to application of an in-office bleaching gel. Bleaching was performed with 35% hydrogen peroxide gel (three applications × 15 minutes each) over two sessions, one week apart. The color of the anterior teeth was evaluated before and 21 days after treatment using the VITA Classical shade guide, Bleachedguide 3D, and Easyshade spectrophotometer. TS during and after the bleaching was recorded according to the visual analog (VAS) and numerical rating (NRS) scales. All data were submitted to statistical analysis (α=0.05). RESULTS: There was no significant difference in absolute risk or intensity of TS between the two groups (risk and VAS, p=0.93 and 0.31, respectively; NRS, p≥0.45). At the end of the bleaching protocol, tooth whitening was observed in both groups, as evident from color change in shade guide units (ΔSGU, 4.1-7.1; both guides) and overall color change (ΔE, 7.4-9.3 units); however, there were no significant differences in whitening between the two groups ( p>0.11). CONCLUSION: Gluma Desensitizer Liquid was not able to reduce the risk or intensity of TS. Bleaching efficacy was not affected by application of the desensitizer.

Dental Restorative Materials Based on Thiol-Michael Photopolymerization.

Step-growth thiol-Michael photopolymerizable resins, constituting an alternative chemistry to the current methacrylate-based chain-growth polymerizations, were developed and evaluated for use as dental restorative materials. The beneficial features inherent to anion-mediated thiol-Michael polymerizations were explored, such as rapid photocuring, low stress generation, ester content tunability, and improved mechanical performance in a moist environment. An ester-free tetrafunctional thiol and a ultraviolet-sensitive photobase generator were implemented to facilitate thiol-Michael photopolymerization. Thiol-Michael resins of varied ester content were fabricated under suitable light activation. Polymerization kinetics and shrinkage stress were determined with Fourier-transform infrared spectroscopy coupled with tensometery measurements. Thermomechanical properties of new materials were evaluated by dynamic mechanical analysis and in 3-point bending stress-strain experiments. Photopolymerization kinetics, polymerization shrinkage stress, glass transition temperature, flexural modulus, flexural toughness, and water sorption/solubility were compared between different thiol-Michael systems and the BisGMA/TEGDMA control. Furthermore, the mechanical performance of 2 thiol-Michael composites and a control composite were compared before and after extensive conditioning in water. All photobase-catalyzed thiol-Michael polymerization matrices achieved >90% conversion with a dramatic reduction in shrinkage stress as compared with the unfilled dimethacrylate control. One prototype of ester-free thiol-Michael formulations had significantly better water uptake properties than the BisGMA/TEGDMA control system. Although exhibiting relatively lower Young's modulus and glass transition temperatures, highly uniform thiol-Michael materials achieved much higher toughness than the BisGMA/TEGDMA control. Moreover, low-ester thiol-Michael composite systems show stable mechanical performance even after extensive water treatment. Although further resin/curing methodology optimization is required, the photopolymerized thiol-Michael prototype resins can now be recognized as promising candidates for implementation in composite dental restorative materials.

Effect of Fiber Post Cementation Timing on the Bond Strength of Resin Cements in Epoxy Resin-Obturated Canals.

This study evaluated the influence of timing after endodontic treatment and type of resin cement used on the bond strength of fiber posts to epoxy resin-obturated canals. A total of 80 bovine incisor roots were divided into four groups (n = 20). Glass fiber posts were cemented at two different times, immediately or 7 days after endodontic treatment, using either a dual-curing resin cement (RelyX ARC, 3M ESPE) or a self-adhesive resin cement (RelyX U200, 3M ESPE). Following post cementation, the samples were cross-sectioned into slices containing root dentin, cement, and fiber post at the cervical, mid, and apical root thirds. The push-out test was performed on a universal testing machine. Three-way analysis of variance for randomized blocks showed no significant effect within the triple interaction (P = .394) or between the double interactions cement-timing (P = .395), cement-root thirds (P = .996), and timing-root thirds (P = .331). The main factor cement revealed a significant effect, showing that regardless of the timing and root third, RelyX ARC provided significantly higher bond strength values than U200. Regardless of root third and timing, the dual-curing resin cement showed higher bond strength to root dentin when the canals were filled with epoxy resin-based cement.

Short- and Long-Term Bond Strength Between Resin Cement and Glass-Ceramic Using a Silane-Containing Universal Adhesive.

This study aimed to evaluate the effect of various silane-containing solutions on bonding between resin cement and glass ceramic after 24 hours and after six months of water storage. Glass-ceramic plaques (IPS e.max CAD) were sandblasted with aluminum oxide, etched with 10% hydrofluoric acid (HF), and divided into five "silane treatment" groups: RelyX Ceramic Primer (RCP), RelyX Ceramic Primer and Single Bond Plus (RCP+SB), Scotchbond Universal (SBU), Clearfil Ceramic Primer (CP), and no solution (HF-only control). Each group was divided into two "storage time" subgroups: 24 hours or six months in 37°C water. Eighteen resin cement cylinders (RelyX Ultimate) were bonded to each treatment group substrate (n=18) and then subjected to microshear testing. Failure mode was analyzed using scanning electron microscopy. Debond data were analyzed using a two-way analysis of variance and the Tukey post hoc test (α=0.05) as well as Weibull distributions. The factors "silane treatment," "storage time," (p<0.0001), and their interaction were statistically significant (p<0.0010). Group means (MPa±SD), RCP (24 hours: 27.2±3.1; six months: 18.0±4.9), and HF-only control (24 hours: 21.1±3.4; six months: 15.7±5.8) showed a reduced bond strength after six months of water storage, while RCP + SB (24 hours: 23.4±4.4; six months: 22.2±5.4), SBU (24 hours: 18.8±3.0; six months: 17.2±3.6), and CP (24 hours: 21.7±4.3; six months: 17.4±4.8) remained constant. Weibull analysis revealed that more reliable bond strengths were obtained after six months for SBU and RCP + SB. Evaluation by scanning electron microscopy revealed that all groups demonstrated hydrolytic degradation at six months of storage, but RCP + SB and SBU indicated less. Use of a separate application of silane and adhesive system improved short and long-term ceramic/resin cement bond strength.

Longevity of metal-ceramic crowns cemented with self-adhesive resin cement: a prospective clinical study

Resin cements are often used for single crown cementation due to their physical properties. Self-adhesive resin cements gained widespread due to their simplified technique compared to regular resin cement. However, there is lacking clinical evidence about the long-term behavior of this material. The aim of this prospective clinical trial was to assess the survival rates of metal-ceramic crowns cemented with self-adhesive resin cement up to six years. One hundred and twenty-nine subjects received 152 metal-ceramic crowns. The cementation procedures were standardized and performed by previously trained operators. The crowns were assessed as to primary outcome (debonding) and FDI criteria. Statistical analysis was performed using Kaplan-Meier statistics and descriptive analysis. Three failures occurred (debonding), resulting in a 97.6% survival rate. FDI criteria assessment resulted in scores 1 and 2 (acceptable clinical evaluation) for all surviving crowns. The use of self-adhesive resin cement is a feasible alternative for metal-ceramic crowns cementation, achieving high and adequate survival rates.