Potential Toxicity Evaluation for a Nano-modified Veneering Ceramic System. Experimental Study in Dogs

Abstract

Statement of problem: Although feldspathic porcelain is esthetic and biocompatible, it's considered a weak point in zirconia restorations. Researches are necessary to improve its flexural strength without affecting biological properties. Purpose: to evaluate the possible toxic effects of incorporating ZrO 2 Nanoparticles into conventional veneering ceramic system. Materials and Methods: Four veneering ceramic systems [Ex0, Ex5, Ex10&Ex20] were formulated by incorporating zirconia NPs into feldspathic powder [0%, 5%,10% & 20% wt.] respectively. Twenty dogs were grouped into 4 groups to receive the 4 experimental ceramic systems. The 3rd mandibular premolar for each dog was prepared for zirconia crowns. Impressions were taken for production of zirconia copings, veneered with experimental ceramics & delivered. After 3& 6 months gingival specimens were collected& subjected to Real-time PCR test to assess genotoxicity of the 4 experimental veneering ceramics. Results: No genotoxicity was recorded for all groups in both 3& 6 months. However, appoptic genes recorded in Ex0: 0.64±0.01 &0.65±0.02, Ex5: 0.67±0.02& 0.67±0.01, Ex10:0.72±0.01 &0.73±0.02 and in Ex20: 0.88±0.01& 0.89±0.01 compared to control (housekeeping gene) 0.96± 0.01 & 0.99±0.01 for3&6 months respectively. From clinical perspective; No local biological reactions were recorded. Conclusion: No genotoxic effect was recorded in all groups. whereas, appoptic genes expressed higher level in proportional to NPs ratio. Generally, a satisfactory soft tissue response was observed.

Sustainable nanotechnology based wastewater treatment strategies: achievements, challenges and future perspectives

“…The properties such as shape, sizing (dimension), reactivity, etc. can make them harmful to living organisms, although these are the properties that actually make them useful (Hillie andHlophe 2007, Eldessouky andAli 2021). Nanoparticle introduction into the bloodstream or through skin, inhalation, ingestion, etc.…”

“…This results in damage to membranes, DNA and proteins due to oxidative stress and inflammation due to generated ROS (Nel, Xia et al 2006, Eldessouky andAli 2021). When absorbed on the body surface, nanoparticles can alter enzyme mechanisms and certain proteins (Hubbs, Mercer et al 2011).…”