Antibacterial, Antibiofilm, and Tooth Color Preservation Capacity of Magnesium Oxide Nanoparticles Varnish (in vitro Study).

Purpose: Antibacterial and antibiofilm properties of magnesium oxide nanoparticles (MgONPs) mixture assessed against Streptococcus mutans (S. mutans), in addition to examining MgONPs varnish impact on the preservation of the tooth color and inhibition of methylene blue diffusion to the enamel. Methods: MgONPs mixture was prepared in deionized water (DW), absolute ethanol (E), and rosin with ethanol (RE), named varnish. The antibacterial and antibiofilm capacities of MgONPs mixtures were tested by agar well diffusion, colony-forming unit (CFU), and biofilm inhibition microtiter methods in triplicate and compared to sodium fluoride varnish (NaF) and chlorhexidine mouthwash (ChX). A spectrophotometer was used to record basic tooth color. The artificial demineralization was initiated for 96 h. Then, experimental materials were applied to the corresponding group, and 10-day pH cycles proceeded. Then, the color was recorded in the same ambient environment. The methylene blue diffusion was evaluated by staining the samples for 24 h. After that, the diffusion test was calculated by a digital camera attached to the stereomicroscope. Results: The agar well diffusion test expressed a significant inhibition zone with all MgONPs mixtures (p = 0.000), and maximum inhibition zone diameter associated with MgONPs-RE. The same finding was observed in the CFU test. Additionally, 2.5%, 5%, and 10% MgONPs-RE varnish showed strong biofilm inhibition capacity (p = 0.039) compared to NaF and ChX groups that inhibit biofilm formation moderately (p = 0.003). The study shows that the 5% MgONPs-RE varnish maintains basic tooth color with minimal methylene blue diffusion compared to NaF varnish (p = 0.00). Conclusion: Evaluating MgONPs as a mixture revealed antibacterial and antibiofilm capacity against S. mutans with a higher effect of MgONPs-RE varnish. Also, examining the topical effect of MgONPs-RE varnish on the preservation of the tooth color after pH cycle challenges and methylene blue diffusion to enamel confirmed the high performance of MgONPs-RE varnish at 5%.

Association of dental and gingival health status with level of salivary characteristics and Streptococcus mutans in children.

BACKGROUND/PURPOSE: Caries and periodontal diseases are the most common oral diseases that lead to teeth loss. The aim of this study is to assess the association of combination of salivary characteristics, Streptococcus mutans levels and clinical parameters to the dental and gingival health statuses of children. MATERIALS AND METHODS: Saliva samples were collected from 89 children. Children were allocated to the low caries group (45 children: mean DMFT/dmft ≤ 2) or high caries group (44 children: mean DMFT/dmft ≥ 5) according to WHO method and criteria. Additionally, gingival health status was assessed as fair (gingival index and plaque index < 2) or bad (gingival index and plaque index ≥ 2). Each participant's resting saliva hydration (RSH), viscosity (RSV), pH (RSpH), stimulated saliva flow rate (SSFR), buffering capacity of saliva (BCSS) and level of S. mutans (SSM) were determined by chair side test kits. RESULTS: The result showed statistically significant differences in all salivary characteristics and SSM levels for both types of dentition between the low and active caries groups as well as between fair and bad gingival health status (except for RSH for permanent teeth and RSH plus SSFR for primary teeth). Logistic regression showed that combination of plaque index (PI), RSH, RSV, RSpH and SSM provided accurate association (permanent teeth: 92.1%, primary teeth: 100%) of caries status and PI plus BCSS provided accurate association (permanent teeth: 92.1%, primary teeth: 93%) of gingival health status. CONCLUSION: This study has suggested that combination of salivary characteristics, PI and SSM levels could provide significant association of caries and gingival health statuses of children.