The Effect of Sealer Application Methods on Voids Volume after Aging of Three Calcium Silicate-Based Sealers: A Micro-Computed Tomography Study.

During obturation, air voids are undesirable as they may provide shelter for microorganisms or passage for fluids. This study aimed to compare the occurrence of voids between three calcium silicate-based sealers (CSBSs) (MTA-Fillapex, BioRoot-RCS, Bio-C) and the change in their volume after aging. In addition, we aimed to compare voids when using two sealer application methods: lentulo-spiral (LS) and gutta-percha (GP) cone. Thirty extracted mandibular premolars (n = 30) were endodontically prepared and obturated using single GP cone (SGPC) technique. Each sealer was applied to 10 teeth (n = 10) using LS or GP. Micro-computed tomography (micro-CT) was used to quantify the volume of root filling and voids before and after 8-week storage in a phosphate-rich medium. The percentage of root filling and voids were compared between the groups using a Mann-Whitney U test and Kruskal-Wallis test with a Bonferroni correction. Before aging, the percentages of root filling volume after obturation were comparable with no significant differences between sealers (p = 0.325) or application methods (p = 0.950). After aging, the voids' volume increased significantly in all sealers (p ≤ 0.05). However, no significant differences were found between sealers (p = 0.302). In conclusion, voids in CSBSs may not reduce in size with aging; hence, SGPC should be carefully selected for suitable cases.

The Bond Strength of a Universal Adhesive System with Silane to Lithium Disilicates in Comparison with an Isolated Silane Coupling Agent.

PURPOSE: The aim of this in vitro study was to evaluate the effects of different durations of silane coupling agent application compared to a universal adhesive system regarding the shear bond strength of two ceramic materials. MATERIALS AND METHODS: A total of 120 human molars were ground to the dentinal coronal third and then fixed into an acrylic resin holder. Lithium disilicate specimens were divided into two main groups according to the ceramic type: computer-aided design/computer-aided manufacturing IPS e.max CAD and heat-pressed Initial LiSi Press GC (dimensions of 4 × 3× 3 mm). Each main group was subdivided into 6 subgroups (n = 10) according to the duration of the silane and universal adhesive system application (20, 60, or 120 seconds) on the ceramic surface before cementation; then, the cementation procedures were performed. All specimens were subjected to 5000 thermal cycles at 5 and 55°C before testing. The shear bond strength was measured using a universal testing machine. ANOVA and Scheffe post hoc test multiple comparisons tests were conducted (α = 0.05). RESULTS: The shear bond strength increased as the duration of the silane and universal adhesive system application increased. The highest bond value for each material was found for the silane application at 120 seconds, with a significant difference between 120 and 60, and 20 seconds for both e. max CAD and Initial LiSi materials (p = 0.029 and p ˂ 0.001, respectively). No significant difference was found between 60 and 20 seconds when silane and universal adhesive system were applied for both e. max CAD and Initial LiSi materials (p = 0.169 and p = 0.120, respectively). All groups treated with the silane primer showed significantly higher values than the universal adhesive system for each application time (p ˂ 0.001). CONCLUSION: Increasing the duration of the silane coupling agent and universal adhesive system application to 120 seconds on the ceramic surface before cementation improved the shear bond strength of the ceramic-cement interface. Ceramic pretreatment with silane could be an essential step for bonding ceramic to dentin regardless of silane presence in the universal adhesive system.

Pattern of dental needs and advice on Twitter during the COVID-19 pandemic in Saudi Arabia.

AIM: To compare and evaluate the influence of the COVID-19 outbreak on tweets related to dental treatment needs and advice of Saudi Twitter users in 2020 by comparing them to the same time-period in 2019. METHODS: Eight independent searches based on dentistry related keywords: "teeth, mouth and gingiva" were carried out within the timeframe between the 23rd of March and the 21st of June for the years 2020 and 2019. Extracted tweets were analyzed by two calibrated examiners as tweets containing expressed dental needs and tweets for dental advice, while spam tweets were excluded. Descriptive analysis was performed to present the overview of the findings using SPSS. Bivariate analysis was performed with Pearson's Chi Square, Fisher's Exact test and Mann-Whitney U test. Statistical significance was set at p ≤ 0.05. RESULTS: A total of 595 tweets from the year 2019 and 714 tweets from the year 2020 were obtained. Overall, combined dental needs and advice tweets, retweets, likes, and replies were higher in 2020 compared to 2019. Dental needs tweets were higher in 2020 compared to 2019, while dental advice tweets were lower in 2020 compared to 2019. Statistically significant differences were found between 2020 and 2019 with regards to dental needs well as with dental advice (p < 0.05). In addition, statistically significant differences were found between 2019 and 2020 with presence of pain, urgency of the dental need and type of advisor (p < 0.05). CONCLUSION: An obvious impact of the pandemic can be seen in the form of increased self-reported dental needs, pain and urgency among the public in Saudi Arabia. This study highlights the importance of social media, specifically Twitter, in expressing the public needs and utilizing it as a platform for education and advice.

Dental Care in the Arab Countries During the COVID-19 Pandemic: An Infodemiological Study.

BACKGROUND: Twitter is a powerful platform which could be used to reflect on the demand and supply of dental services during a pandemic. The aim of this study was to examine the nature and dissemination of COVID-19 information related to dentistry on Twitter platform Arabic database during the COVID-19 pandemic. METHODOLOGY: One hundred and fifty independent searches with a combination of keywords for both COVID-19 and dentistry from a preselected Arabic keyword were carried out for the period from the 2nd of March (first confirmed cases of COVID-19) to the 6th of July 2020. Tweets were filtered to remove duplicate and unrelated tweets. The suitable tweets were 1,150. After calibration, two examiners coded the tweets following two main themes: COVID-19 and oral health-related information. Tweets were then compared with COVID-19 daily events in the Arab countries as reported by the World Health Organization (WHO). Descriptive analysis was performed to present the overview of the findings using Microsoft Excel. RESULTS: The most retweeted information was the help with urgent consultation or emergency dental treatment during COVID-19 tweeted by a dentist. There were 673 retweets and 1,116 likes of this tweet. The most common tweets related to oral health were needs of dental treatment (n=462, 39.5%) of which, toothaches or wisdom tooth problems constituted 48% of the related tweets. CONCLUSION: Based on the results of this study, it is obvious that social media users reacted to the COVID-19 threat to dental practices. Twitter as one of the social media platforms served as a connection between dental health professionals and patients.