Objective To provide a comprehensive and systematic analysis of demographic characteristics, clinical symptoms, laboratory findings and imaging features of coronavirus disease 2019 (COVID‐19) in pediatric patients. Methods A meta‐analysis was carried out to identify studies on COVID‐19 from December 25, 2019 to April 30, 2020. Results A total of 48 studies with 5829 pediatric patients were included. Children at all ages were at risk for COVID‐19. The main illness classification ranged as: 20% (95% CI: 14 to 26%, I 2 =91.4%) asymptomatic, 33% (95% CI: 23 to 43%, I 2 =95.6%) mild and 51% (95% CI: 42 to 61%, I 2 =93.4%) moderate. The typical clinical manifestations were fever 51% (95% CI: 45 to 57%, I 2 =78.9%) and cough 41% (95% CI: 35 to 47%, I 2 =81.0%). The common laboratory findings were normal white blood cell 69% (95% CI: 64 to 75%, I 2 =58.5%), lymphopenia 16% (95% CI: 11 to 21%, I 2 =76.9%) and elevated creatine‐kinase MB (CK‐MB) 37% (95% CI: 25 to 48%, I 2 =59.0%). The frequent imaging features were normal images 41% (95% CI: 30 to 52%, I 2 =93.4%) and ground‐glass opacity 36% (95% CI: 25 to 47%, I 2 =92.9%). Among children under 1‐year old, critical cases account for 14% (95% CI: 13 to 34%, I 2 =37.3%) that should be of concern. In addition, vomiting occurred in 33% (95% CI: 18 to 67%, I 2 =0.0%) cases that may also need attention. Conclusions Pediatric patients with COVID‐19 may experience milder illness with atypical clinical manifestations and rare lymphopenia. High incidence of critical illness and vomiting symptoms reward attention in children under 1‐year old. This article is protected by copyright. All rights reserved.

Giomer restoratives, like other direct and indirect composites, are softened by foodsimulating liquids, especially citric acid and ethanol. They are also roughened by citric acid. SUMMARYThis study examined the effects of food-simulating liquid (FSL) on the hardness and roughness of giomer restoratives based on prereacted glass ionomer (PRG) technology. The materials investigated included a regular (Beautifil II [BT]) and a recently introduced injectable (Beautifil Flow Plus F00 [BF]) hybrid PRG composite. A direct hybrid composite (Filtek Z250 [ZT]) and an indirect hybrid composite (Ceramage [CM]) were used for comparison. The materials were placed into customized square molds (5 mm 3 5 mm 3 2.5 mm), covered with Mylar strips, and cured according to manufacturers' instructions. The materials were then conditioned in air (control), distilled water, 50% ethanol solution, and 0.02 N citric acid at 378C for seven days. Specimens (n=6) were then subjected to hardness testing (Knoop) and surface profilometry. Data were analyzed using one-way analysis of variance and post hoc Scheffe test (p,0.05). Mean Knoop hardness values for the control group (air) ranged from 53.4 6 3.4 (BF) to 89.5 6 5.2 (ZT), while mean surface roughness values values ranged from 0.014 6 0.002 (ZT) to 0.032 6 0.001 (BT). All materials were significantly softened by FSL. The degree of soften-

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Abstract. Increasing evidence suggests that aberrant