Mouth shield to minimize airborne transmission risk of COVID-19 and other infectious diseases in the dental office.

Transmission of coronavirus disease (COVID-19) and other infectious diseases is a significant risk during dental procedures because most dental interventions involve aerosols or droplets that could contaminate the surrounding environment. Current protection guidelines to address the high risk of droplets, aerosols, and airborne particle transmission of COVID-19 in the dental office recommend minimizing aerosol-generating procedures. In this paper, an innovative mouth shield is presented that should minimize water backsplash from the air-water syringe during dental treatment. The mouth shield can be added to the personal protective equipment to provide the dental team with extra protection. It can be made of different materials, is straightforward, inexpensive, and safe to fabricate, and is easy to use.

COVID-19 Vaccine Hesitancy Associated With Vaccine Inequity Among Healthcare Workers in a Low-Income Fragile Nation.

Objectives: Preventing severe disease and acquiring population immunity to COVID-19 requires global immunization coverage through mass vaccination. While high-income countries are battling vaccine hesitancy, low-income and fragile nations are facing the double dilemma of vaccine hesitancy and lack of access to vaccines. There is inadequate information on any correlation between vaccine hesitancy and access to vaccines. Our study in a low-income nation aimed to fill this gap. Methods: In the backdrop of a severe shortage of COVID-19 vaccines in Yemen, a low-income fragile nation, we conducted a nation-wide cross-sectional survey among its healthcare workers (HCWs), between 6 July and 10 August 2021. We evaluated factors influencing agreement to accept a COVID-19 vaccine and any potential correlation between vaccine acceptance and lack of access to vaccines. Results: Overall, 61.7% (n = 975) of the 1,581 HCWs agreed to accept a COVID-19 vaccine. Only 45.4% of the participants agreed to have access to a COVID-19 vaccine, with no sex dependent variations. Although several determinants of vaccine acceptance were identified, including, having a systemic disease, following the updates about COVID-19 vaccines, complying with preventive guidelines, having greater anxiety about contracting COVID-19, previous infection with COVID-19, believing COVID-19 to be a severe disease, and lower concern about the side effects of COVID-19, the strongest was access to vaccines (OR: 3.18; 95% CI: 2.5-4.03; p-value: 0.001). Conclusion: The immediate and more dangerous threat in Yemen toward achieving population immunity is the severe shortage and lack of access to vaccines, rather than vaccine hesitancy, meaning, improving access to vaccines could lead to greater acceptance.

The effect of thermocycling on the adhesion of self-etching adhesives on dental enamel and dentin.

AIM: The aim of the present study was to investigate the effectiveness of one total-etch self-priming adhesive and two one-step self-etching adhesive systems on the adhesion of a resin composite to both dentin and enamel. The effect of thermocycling on the adhesion was also investigated. The null hypothesis tested was thermocycling would not affect bond strengths to enamel and dentin treated with self-etching adhesives or a total-etch adhesive. METHODS AND MATERIALS: Two single-step self-etching adhesives [Xeno III (XE3) and Prompt L-Pop (PP)] and one two-step total-etch adhesive system (Prime & Bond NT) (P&B NT) were used in this study. Thirty caries-free unrestored human third molars were used to make specimens of enamel and dentin. Different adhesives were applied on enamel and dentin surfaces according to the manufacturer's instructions then hybrid composite restorative material was condensed on the surface using a mold. The bonded specimens were stored in distilled water at 37 masculineC for 24 hours before being tested. Half of the bonded specimens were tested for shear bond strength without thermocycling. The other half of the test specimens were thermocycled using a thermocycling apparatus in water baths held at 5 masculineC and 55 masculineC with a dwell time of one minute each for 10,000 cycles prior to shear testing. The mean shear bond strength before and after thermocycling was calculated, and the results were subjected to two-way analysis of variance (ANOVA) and repeated measure design to show the interaction between different materials and different times. RESULTS: The results showed shear bond strength on both enamel and dentin of the total-etch adhesive and the self-etching adhesives decreased after the specimens were subjected to thermocycling. CONCLUSIONS: The null hypothesis tested "thermocycling would not affect bond strengths treated with self-etching adhesives" was rejected. Furthermore, the study revealed the following: 1. The shear bond strength to both enamel and dentin of the total-etch adhesive and the self-etching adhesives decreased after the specimens were subjected to thermocycling. 2. XE3 achieved the highest bond strength to both enamel and dentin (26.994+/-1.17 and 25.22+/-1.26, respectively). 3. XE3 showed even better bonding after thermocycling to enamel and dentin than the total-etching system or PP. 4. Although PP bonded to enamel showed lower shear bond strength value than XE3, it has durable bond strength even after thermocycling.

Immediate and 24-hour bond strengths of two dental adhesive systems to three tooth substrates.

Bond strengths of bonded composite resins to tooth substrates vary depending on when they were measured. Most bond strengths reported in the literature are a result of one hour, 24-hour, or longer periods of time that do not simulate actual clinical practice when occlusal adjustment and finishing and polishing procedures are performed within seconds after restoration placement. There are many different ways to measure the bond strength of direct esthetic restorations to various dental substrates. This research uses a method published previously that compares immediate and 24-hour bond strengths of a single-bottle dental adhesive and a self-etching primer adhesive to prepared enamel, unprepared enamel, and prepared dentin substrates. Significant differences were found between immediate and 24-hour bond strengths, but there were essentially no differences between substrates or adhesives.

Method for immediate measurement of in vitro bond strength of bonded direct esthetic restorations.

There are many different ways to measure the bond strength of direct esthetic restorations to various dental substrates. Unfortunately, most methods cannot measure bond strengths immediately after a restoration has been placed. This lack of clinically-relevant information seriously affects the clinician's ability to select and use various bonding agents and procedures. The aim of this article is to provide a very detailed method for immediate measurement of in vitro bond strengths of direct bonded esthetic restorations. It focuses on the steps that should be taken to select and prepare various tooth substrates for bond strength testing, the steps to "restore" various tooth substrates, and to measure the immediate in vitro bond strength. A fundamental understanding of a standardized testing protocol should provide clinicians with a clearer appreciation of bond strengths associated with various bonding procedures.

Influence of timing of coronal preparation on retention of cemented cast posts and cores.

PURPOSE: This study investigated the effect of coronal preparation by high-speed handpiece on the retention of cemented cast posts and cores. MATERIALS AND METHODS: Cast posts and cores were fabricated for 90 extracted single-rooted human teeth cemented with zinc-phosphate cement and randomly divided into six groups of 15 specimens each. The six groups were matched randomly two by two, such that one of each of the matched groups was subjected to a 4-minute period of high-speed preparation of the cores. Castings from the first pair (1 and 2) were subjected to an axially directed removal force using a universal testing machine 15 minutes from the start of cement mixing; castings from the second (3 and 4) and third (5 and 6) pairs were tested at 1 hour and 24 hours, respectively, having been stored in water at 37 degrees C for the waiting periods. The forces required for dislodgment of posts from their prepared spaces were recorded. Data were statistically analyzed using two- and one-way ANOVA and the Student's t test. RESULTS: The results showed increased mean retentive strengths of posts as the time to testing increased for both unprepared and prepared groups. Significantly higher mean retentive strengths of posts were recorded for unprepared compared to prepared groups tested at 15 minutes and 1 hour after cementation. CONCLUSION: High-speed preparation had a significant negative effect on the retentive strengths of posts tested at 15 minutes and 1 hour after cementation, but not on those tested at 24 hours.