L-arginine-containing mesoporous silica nanoparticles embedded in dental adhesive (Arg@MSN@DAdh) for targeting cariogenic bacteria.

Dental caries is the major biofilm-mediated oral disease in the world. The main treatment to restore caries lesions consists of the use of adhesive resin composites due to their good properties. However, the progressive degradation of the adhesive in the medium term makes possible the proliferation of cariogenic bacteria allowing secondary caries to emerge. In this study, a dental adhesive incorporating a drug delivery system based on L-arginine-containing mesoporous silica nanoparticles (MSNs) was used to release this essential amino acid as a source of basicity to neutralize the harmful acidic conditions that mediate the development of dental secondary caries. The in vitro and bacterial culture experiments proved that L-arginine was released in a sustained way from MSNs and diffused out from the dental adhesive, effectively contributing to the reduction of the bacterial strains Streptococcus mutans and Lactobacillus casei. Furthermore, the mechanical and bonding properties of the dental adhesive did not change significantly after the incorporation of L-arginine-containing MSNs. These results are yielding glimmers of promise for the cost-effective prevention of secondary caries.

One-year clinical performance of lithium disilicate versus resin composite CAD/CAM onlays.

To compare the 1-year clinical performance of lithium disilicate and resin composite CAD/CAM onlay restorations. Twenty patients that required two restorations in posterior teeth, with at least one cusp to be covered, received two onlays. One was made with IPS e.max CAD (Ivoclar-Vivadent) and the other with Lava Ultimate (3M Oral Care). Two blind observers evaluated the restorations at baseline and 1 year after the onlays were cemented, according to FDI criteria. At each recall, digital photographs, bite-wing radiographs and impressions of the restorations were taken for SEM evaluation of the interface. Results were analyzed by Mann-Whitney U and Wilcoxon tests (p < 0.05). At baseline and in the 1-year recall, both CAD/CAM materials exhibited excellent results in most criteria with similar esthetic, functional and biological properties (p > 0.05). However, deterioration in surface lustre (p = 0.020) and color match/translucency (p = 0.039) were detected for IPS e.max CAD onlays after 1-year. Under SEM evaluation, there were no statistically differences in micromorphological criteria at baseline nor after a year between IPS e.max CAD and Lava Ultimate onlays. Conclusion: After 1 year of clinical service IPS e.max CAD and Lava Ultimate onlays showed a similar clinical performance that needs to be confirmed in long-term evaluations.

Influence of proximal box elevation on bond strength of composite inlays.

OBJECTIVES: The objective of the present study was to evaluate the influence of proximal box elevation on microtensile bond strength (mTBS) of composite inlays to the proximal box floor, using either a total-etch or a self-adhesive resin cement. MATERIALS AND METHODS: Twenty-five human molars were selected, and a class II OM (inlay) cavity preparation was performed in each tooth. Cavities were randomly assigned into four experimental groups, according to the location of the proximal cervical margin (located 1 mm below cementoenamel junction (CEJ), or with proximal box elevation with composite resin) and the resin cement used for luting (a total-etch resin cement RelyX ARC or a self-adhesive resin cement G-Cem). After 1-week water storage, samples were subjected to mTBS test. Results were analyzed by Kruskal-Wallis and Mann-Whitney U tests (p < 0.05). RESULTS: Kruskal-Wallis revealed statistically significant differences among experimental groups (p = 0.007). Both resin cements showed similar bond strength values when cervical margin was located below CEJ. The proximal box elevation improved the bond strength of composite inlays for both resin cements. However, only for G-Cem was this improvement statistically significant. CONCLUSIONS: The proximal box elevation improved the bond strength attained by G-Cem resin cement. For RelyX ARC, the position of the cervical margin did not affect composite inlays bond strength. CLINICAL RELEVANCE: Proximal box elevation does not decline bond strength of composite inlays to the proximal floor when a total-etch or a self-adhesive resin cement is used.

Living and Coping with Olfactory and Taste Disorders: A Qualitative Study of People with Long-COVID-19.

Taste and smell disorders are common symptoms of SARS-CoV-2 acute infection. In post-COVID-19 condition, symptoms can persist leading to disruption in patients' lives, to changes in their coping skills, and to the need to develop strategies for everyday life. This study aimed to describe the perspective of a group of patients with Long-COVID-19, a condition where loss of taste and/or smell was the most predominant symptom. A qualitative descriptive study was conducted. Participants who had suffered SARS-CoV-2 infection and had Long-COVID-19 loss of taste and/or smell were recruited. Purposive sampling was applied, and participants were recruited until data redundancy was reached. In-depth interviews were used for data collection and thematic analysis was applied. Twelve COVID-19 survivors (75% women) were recruited. The mean age of the participants was 55 years, and the mean duration of post-COVID-19 symptoms was 25 months. Three themes were identified: (a) Living with taste and smell disorders, describing the disorders they experience on a daily basis, how their life has changed and the accompanying emotions, (b) Changes and challenges resulting from the loss of taste and smell, changes in habits, self-care and risk in certain jobs or daily activities, (c) Coping with taste and smell disorders, describing the daily strategies used and the health care received. In conclusion, Long-COVID-19 taste and/or smell disorders limit daily life and involve changes in habits, meal preparation, and the ability to detect potentially dangerous situations.

Impact of COVID-19 on the work of Spanish dentists: An early response to the pandemic.

BACKGROUND: This study aimed to assess the quality of the information about COVID-19 that Spanish dentists felt they were provided; their opinion about the actions by Health Institutions; their perception of the risk infection at work; and the security measures implemented to prevent contagion. MATERIAL AND METHODS: A specific questionnaire was developed and made available online from March 18th to 20th 2020. Dentists working in Spain were invited to answer. Questions were divided in 4 sections: demographic data and professional activity; specific information on COVID-19 and opinion about the decisions taken by Dental Councils and Health Authorities; risk assessment for SARS-CoV-2 in dental practices; and implementation of new ways of working. Chi-square tests were computed (p<0.05). 873 dentists answered the survey. RESULTS: A majority of dentists considered that Health Authorities did not take right decisions during the outbreak (86.37%), and were concerned both about getting infected at work (83.16%) and being a potential carrier to their patients (72.97%). Due to COVID-19, 59.11% of the dentists incorporated new protective measures in the dental practice, 60.17% began dealing with emergencies only and 39.18% stopped working. CONCLUSIONS: Most dentists were worried about infection in their workplaces, particularly women and dentists from the most affected regions by COVID-19. Almost 90% of the participants considered that this pandemic will change the way they provide dental care in the future. Key words:COVID-19, pandemic, disease transmission, dentists´ behavior, dental practice.

The influence of irrigation solutions in the inorganic and organic radicular dentine composition.

The aim of this study was to analyse changes in radicular dentine composition after different irrigation regimes using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Dentine slices from human single-root teeth were immersed in: (i) 5.25% sodium hypochlorite (NaOCl) for 1, 5 and 20 min; (ii) 17% EDTA for 1 min; and (iii) 5.25% NaOCl for 20 min, and 17% EDTA and 5.25% NaOCl, both for 1 min. Carbonate/mineral, Amide I/mineral and Amide III/CH2 ratios were determined using ATR-FTIR before and after immersion in the irrigation solutions tested. Results showed that 5.25% NaOCl significantly decreased carbonate/mineral, Amide I/mineral and Amide III/CH2 ratios (P < 0.05). Application of 17% EDTA produced no change in carbonate/mineral ratio (P = 0.120), while an increase in Amide I/mineral in apical third (P = 0.002) and Amide III/CH2 (P < 0.001) was observed. The combination of NaOCl, EDTA and NaOCl increased carbonate/mineral ratio in coronal third (P = 0.037), and Amide I/mineral (P = 0.003) and Amide III/CH2 (P = 0.001) ratios. In conclusion, irrigation solutions tested significantly affected radicular dentine composition.