Lactoperoxidase (LPO) present in saliva are an important element of the nonspecific immune response involved in maintaining oral health. The main role of this enzyme is to oxidize salivary thiocyanate ions (SCN−) in the presence of hydrogen peroxide (H2O2) to products that exhibit antimicrobial activity. LPO derived from bovine milk has found an application in food, cosmetics, and medical industries due to its structural and functional similarity to the human enzyme. Oral hygiene products enriched with the LPO system constitute an alternative to the classic fluoride caries prophylaxis. This review describes the physiological role of human salivary lactoperoxidase and compares the results of clinical trials and in vitro studies of LPO alone and complex dentifrices enriched with bovine LPO. The role of reactivators and inhibitors of LPO is discussed together with the possibility of using nanoparticles to increase the stabilization and activity of this enzyme.

Secondary caries is a disease associated with the formation of biofilm on the border of the tooth and dental filling. Its development is strongly influenced by the dietary sweet foods and the type of dental material. The aim of the study was to assess the effect of sweeteners on the ability of clinical Streptococcus mutans strains to form biofilm on dental materials. Strains were isolated from plaque samples from 40 pediatric patients from the 3–6 ICADS II group. The ability to form biofilm was tested on composite and glass ionomer dental materials used for milk teeth filling in the presence of sucrose, xylitol, sorbitol, and erythritol. The bacterial film mass after 12, 24, 48, and 72 h and the number of bacterial colonies significantly decreased (p < 0.01) compared to the initial value for 5% erythritol and sorbitol on examined materials. A greater inhibitory effect was noted for glass ionomers compared to composites. Sucrose and xylitol supported biofilm formation, while erythritol had the best inhibitory effect. The use of fluoride-releasing glass ionomers exerted an effect synergistic to erythritol, i.e., inhibited plaque formation and the amount of cariogenic S. mutans. Selection of proper type of dental material together with replacing sucrose with polyols can significantly decrease risk of secondary caries development. Erithritol in combination with glass ionomer seems to be the most effective in secondary caries prevention.

Lactoperoxidase (LPO) together with its (pseudo)halogenation cycle substrates, H2O2 and thiocyanate ions oxidized to hypothiocyanite ions, form one of the main systems involved in antimicrobial defense within the oral cavity. In bacterial diseases such as dental caries, lactoperoxidase is oxidized to a form known as Compound II, which is characterized by its inability to oxidize SCN–, resulting in a decreased generation of antimicrobial products. Reynoutria sp. rizome extracts, due to their high polyphenol content, have been tested as a source of compounds able to regenerate the antimicrobial activity of lactoperoxidase through converting the Compound II to the native LPO state. In the presented study, acetone extracts of R. japonica, R. sachalinensis, and R. x bohemica, together with their five fractions and four selected polyphenols dominating in the studied in extracts, were tested toward lactoperoxidase reactivating potential. For this purpose, IC50, EC50, and activation percentage were determined by Ellman’s method. Furthermore, the rate constants for the conversion of Compound I–Compound II and Compound II–native-LPO in the presence of extracts, extracts fractions, and selected polyphenols were determined. Finally, the ability to enhance the antimicrobial properties of the lactoperoxidase system was tested against Streptococcus mutans. We proved that Reynoutria sp. rhizome is the source of lactoperoxidase peroxidation cycle substrates, which can act as activators and inhibitors of the antimicrobial properties of that system. The presented study shows that the reactivation of lactoperoxidase could become a potential therapeutic target in prevention and treatment support in some infectious oral diseases.

Objective: Dental caries is the most prevalent chronic disease in childhood. It is a social disease, which causes search for effective methods of its prevention. Due to its inhibitory action on Streptococcus mutans, xylitol is a readily used supplement. The purpose of the study was a determination of the effect of 0.01% concentration of xylitol on monospecies S. mutans biofilm formation.Design: Clinical strains were acquired from 64 children aged 4.7 ± 0.81 years. The study group included children with caries and patients without carious lesions. The isolates identified using a MALDI-TOF mass spectrometer. The effect of 0.01% xylitol on monospecies biofilm formation after 8, 24, 48 and 72 h of culturing was evaluated. The produced biofilms were evaluated by determining the biofilm biomass, microorganism concentration and analyzing structure in a scanning electron microscope. Results:The biofilm biomass treated with xylitol was, at every time point, significantly lower (p < 0.001), in both study groups of children compared to the biofilm not treated with xylitol. A statistically significant decrease in the biofilm-forming capacity with xylitol in CFU/mL was obtained after 48 h in both groups. Conclusions:The anti-biofilm efficacy of xylitol at low concentrations, justifies its use in caries prevention in children.

One strategy in caries prevention is to inhibit the formation of cariogenic biofilms. Attempts are being made to develop oral hygiene products enriched with various antimicrobial agents. One of them is lactoperoxidase—an enzyme that can oxidise (pseudo)halide ions to reactive products with antimicrobial activity. Currently, commercially available products utilise thiocyanate as a substrate; however, several alternatives that are oxidised to products with greater antimicrobial potential have been found. In this study, toxicity against human gingival fibroblasts of the lactoperoxidase system was evaluated using four different (pseudo)halide substrate systems—thiocyanate, iodide, selenocyanate, and a mixture of thiocyanate and iodide. For this purpose, cells were treated with the systems and then apoptosis, cell cycle, intracellular glutathione concentration, and mitochondrial superoxide production were assessed. The results showed that each system, after generating 250 µM of the product, inhibited cell divisions, increased apoptosis, and increased the percentage of dead cells. It was concluded that the mechanism of the observed phenomena was not related to increased superoxide production or the depletion of glutathione concentration. These findings emphasised the need for the further in vitro and in vivo toxicity investigation of the modified lactoperoxidase system to assess its safety and the possibility of use in oral hygiene products.