Alrabiah M, et al. J Periodontal Implant Sci. 2020 Apr;50(2):97-105. https://doi.org/10.5051/jpis.2020.50.2.97

Coronavirus disease 2019 (COVID 19) is a major threat to the health and prosperity of human life at present. It has resulted in loss of thousands of lives globally and has brought countries to the brink of economic, social, and health collapse. A major issue of this infection is the ease with which it transmits through salivary droplets and its survival for long durations outside the body. Therefore, its early detection is critical in prevention, diagnostic, and management efforts of COVID-19 patients. Loss of taste and smell is one of the early symptoms reported in these patients and the virus is abundantly found in the salivary secretion of the infected symptomatic and asymptomatic patients. Infection and inflammation of salivary glands are common among viral infections, particularly in the early stages, which lead to salivary composition changes. Chemosensory sensation of taste is critically dependent on the salivary flow rate and its inorganic constituents, protein levels, specific 3′,5′-cyclic adenosine monophosphate and 3′,5′-cyclic guanosine monophosphate levels, ghrelins, pH levels, and enzymes. Therefore, the question arises, “Does COVID-19 infection alter the salivary components and composition leading to early transient symptoms of Ageusia and hypogeusia?” This review shows association of the COVID-19 and Ageusia, in addition to the early viral infection of salivary glands and possible changes in salivary flow and content. Therefore, suggesting a potential association between early ageusia in COVID-19 infection and salivary compositional changes.

Objective. This in vitro study was designed to evaluate the influence of an Er,Cr:YSGG laser on the bond strength of zirconia and glass fiber posts with root dentin. Materials and methods. Ninety extracted single-rooted human teeth were randomized into 6 groups (n = 15/group) on the basis of different posts (zirconia/glass fiber) and Er,Cr:YSGG laser tips (axial and radial). Specimens were prepared for push-out testing with the help of a cutting machine; six slices (2 on each cervical, middle, and apical) of approximately 1 mm thickness were sectioned for all roots on a plane perpendicular to the long axis of the post. All specimens were placed into a universal testing machine with a defined 0.5 mm/min crosshead speed until the maximum failure load was obtained. Results. The highest mean push-out bond strength of the glass fiber and zirconia groups was achieved with laser treatment. The highest push-out bond strength was achieved with the axial fiber tip (7.63 ± 1.22 MPa), and the lowest was achieved with a radial fiber tip of the glass fiber group (6.98 ± 0.96 MPa). ANOVA showed a statistically significant difference between the groups (p=0.041). The mean push-out bond strength was found to be higher with an axial fiber tip for both cervical and apical segments in the glass fiber and zirconia groups (p<0.05). The independent t-test resulted in the overall highest mean push-out bond strength in the apical segments (p=0.026). Conclusion. Within the limits of the present in vitro research study, an enhancement in the push-out bond strength of resin cement, mainly in the cervical region of the root canal, was achieved after irradiation with an Er,Cr:YSGG laser using an axial fiber tip.