Selective Removal of Necrotic Dentin in Primary Teeth Using Laser Irradiation: One-Year Clinical Evaluation of Composite Restorations

Effect of green tea-loaded chitosan nanoparticles on leathery dentin microhardness

The purpose of this study was to assess the effect of a chitosan-based nanoformulation containing green tea on leathery (remaining) dentin subsurface microhardness. Size distribution, polydispersity index (PDI) and zeta potential (mV) of nanoformulations were previously determined by dynamic light scattering (DLS). Human dentin specimens were exposed to Streptococcus mutans for 14 d. Soft dentin were selectively removed by Er:YAG laser (n = 30) or bur (n = 30). Remaining dentin was biomodified with chitosan nanoparticles (Nchi, n = 10) or green tea-loaded chitosan nanoparticles (Gt + Nchi, n = 10) for 1 min. Control group (n = 10) did not receive any treatment. Subsurface microhardness (Knoop) was evaluated in hard (sound) and soft dentin, and then, in leathery dentin and after its biomodification, at depths of 30, 60 and 90 μm from the surface. Nchi reached an average size of ≤ 300 nm, PDI varied between 0.311 and 0.422, and zeta potential around + 30 mV. Gt + Nchi reached an average size of ≤ 350 nm, PDI < 0.45, and zeta potential around + 40 mV. Soft dentin showed significantly reduced microhardness at all depths (p > 0.05). The subsurface microhardness was independent of choice of excavation method (p > 0.05). At 30 µm from the surface, Gt + Nchi increased the leathery dentin microhardness compared to untreated group (p < 0.05). Nchi promoted intermediate values (p > 0.05). Both nanoformulations showed an average size less than 350 nm with nanoparticles of different sizes and stability along the 90-day period evaluated. Subsurface microhardness of bur-treated and laser-irradiated dentin was similar. At 30 µm, the biomodification with Gt + Nchi improved the microhardness of leathery dentin, independently of caries excavation method used.

Use of the Er:YAG Laser in Conservative Dentistry: Evaluation of the Microbial Population in Carious Lesions

The aim of this study is to investigate the Erbium:Yttrio-Aluminum-Granate (Er:YAG) laser photothermal and mechanical effects on cariogenic species concentration and on the microbial load composition of therapeutic cavities, in order to evaluate the possible micro-organisms reduction and make a comparison with manual and rotating conventional therapy (CT). A clinical trial was designed, including adults with active deep carious lesions on permanent teeth who were divided into two groups, i.e., control group and intervention group treated with CT and Er:YAG therapy, respectively. Before and after any conservative treatment, two oral samples were collected using a small sterile microbrush scrubbed within the base of the dentinal cavity tissue. The percentage of reduction and the colony-forming units (CFUs) count after Er:YAG and conventional treatments were compared for total microorganisms, including Candida spp., Streptococcus spp., and Lactobacillus spp. The microbial reduction varied from 90.2% to 100% and was significantly observed for total microorganisms and Streptococcus spp. (p < 0.05). The Er:YAG laser shows the potential for clinical applications, especially with paediatric and complicated patients, thanks to its minimally invasive properties and its effect on the reduction of microbial load.

Efficacy and Patient's Acceptance of Alternative Methods for Caries Removal-a Systematic Review

Dental caries is a disease of dental hard tissues, considered the most common non-communicable disease worldwide. Conventional treatments for caries removal are often associated with pain and fear, so different therapeutic approaches have been developed towards more conservative and pleasant treatments. This systematic review aimed to assess the efficacy and patient's acceptance of alternative methods for caries removal compared to conventional methods. The Cochrane Library, Embase, Medline/Pubmed, Web of Science, and Clinical Trials databases were searched. Clinical trials of primary dental caries treated with alternative methods were included. The last search was performed on 5 August 2020. The Population, Intervention, Comparison, and Outcome (PICO) strategy was followed. Thirty-seven clinical trials were included, reporting caries removal using alternative (chemomechanical-Brix 3000, Carie-care, Carisolv and Papacarie, laser-Er:YAG (Erbium-doped Yttrium Aluminium Garnet) and Er,Cr:YSGG (Erbium, Chromium-doped Yttrium, Scandium, Gallium and Garnet), and a system combining air and sono-abrasion-Vector^® System) and conventional methods. Alternative methods tended to prolong treatment time and lessen anesthesia need. All treatments were effective in reducing cariogenic flora, and the restoration's performance did not differ significantly. Chemomechanical solutions seemed to be the best option towards minimally invasive treatments, with good control during application and action and good treatment experiences for patients. Papacarie was demonstrated to be an effective method for caries removal with less pain, and superior acceptance by patients when compared to conventional treatments.