Survival of different caries managements in children with autism and unaffected peers: a retrospective cohort study.

AIM: Dental caries is a common oral disease in children with special needs such as those with autism spectrum disorders (ASDs). The aim is to assess whether the type and survival of three caries management, conventional resin restorations (CR), ART technique (ART) and SDF application without caries removal (SDF), in primary teeth carried out at the Pediatric Dentistry Department of San Paolo Hospital (University of Milan) differed between children with ASDs and unaffected peers. METHODS: Data from a convenience sample of children with and without ASDs, who have received dental care for caries in primary teeth from January 2019 to June 2022, were analysed. Medical history, age, sex, teeth treated, and type of treatment were collected from dental charts. Data on success and minor and major failures of each treatment were also collected. Two survival analysis were performed, one considering both major and minor failures, a second considering only major failures. Cox Proportional Hazards multivariate logistic models were run to assess factors associated with failures. The statistical significance was set at 5% (p< 0.05). CONCLUSION: In children with autism, the different techniques for approaching caries lesions seem to have the same probability of success. Therefore, the choice of treatment should be patient-oriented rather than lesion-oriented. In unaffected children, the gold standard always seems to be traditional restorative treatment.

A new urinary catheter design reduces in-vitro biofilm formation by influencing hydrodynamics.

AIM: To evaluate the performance of a new catheter design based on different hydrodynamics aiming to reduce the development of biofilm, and compare it with a conventional Foley catheter (FC). METHODS: The new proposed design (NPD) catheter is a modification of the FC, based on asymmetric positioning of the balloon and additional drainage holes allowing continuous urine drainage and complete voiding of the bladder. A first experiment was undertaken to assess drainage capability, and a second experiment was performed using a bioreactor with a set-up simulating the bladder and using the test catheter as a flow-through system. The biofilm formation of five bacterial species associated with catheter-associated urinary tract infection (CAUTI) was determined after 24 h of incubation using an MTT assay. Morphological evaluation was performed using scanning electron microscopy. In-vitro determination of residual fluid, and quantitative and morphological data on biofilm formation on the intravesical and intraluminal parts of the tested catheters were assessed. RESULTS: Residual fluid was significantly higher in the FC (5.60 ± 0.43 mL) compared with the NPD catheter (0.2 ± 0.03 mL). The NPD catheter showed significantly less biofilm formation (P<0.0001) than the FC. Catheter design had a variable effect on biofilm formation depending on the bacterial strain tested. There was significantly less intraluminal biomass compared with intravesical biomass in both catheters (P<0.0001). Multi-layered biofilms that covered the FC surfaces completely were seen for all tested strains, while the NPD catheter surfaces showed reduced biofilm formation. CONCLUSIONS: Modifications of the hydrodynamic characteristics of a catheter can significantly reduce bacterial colonization. Integrated design approaches combining chemical, mechanical and topographical elements can help to reduce the occurrence of CAUTI.

Antibacterial and antibiofilm effects of radioactive thermal water.

OBJECTIVE: Most of the infections of the upper respiratory tract are caused by biofilm-forming microorganisms belonging to the Pseudomonas, Streptococcus, Staphylococcus, and Enterobacter genus. Many of these microorganisms also show antibiotic resistance, partly related to biofilm formation. The treatment of these affections may include inhalation of radioactive thermal water (RTW). The present study aimed to evaluate the in vitro antibiofilm effect of RTW collected from Merano springs, Italy. MATERIALS AND METHODS: A series of experiments were performed evaluating the effect of RTW against planktonic cultures (1 h exposure) and on biofilms (10 min and 1 h exposure) formed by Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. Viable biomass was assessed using a colorimetric assay. A model based on the infection by the same strains of a reconstituted human respiratory epithelium (RHRE) was used to morphologically evaluate the antibiofilm effect of RTW. RESULTS: RTW decreased the viability of S. aureus and S. pneumoniae planktonic cultures by about 20%. RTW also decreased biofilm viability by all strains except for E. coli at both time points. In the RHRE model, bacterial adherence and colonization occurred in all specimens, showing a particular affinity for the epithelium's cilia. Bacterial infections caused significant alterations in the epithelium structure, showing enlargement of the intercellular spaces, and damage to the cell structure. Specimens infected with S. aureus showed slightly lower colonization levels after RTW treatment. CONCLUSIONS: Results of this in vitro study showed a significant effect of RTW against Gram-positive planktonic bacterial cells as well as a significant antibiofilm activity.

Silver-polysaccharide antimicrobial nanocomposite coating for methacrylic surfaces reduces Streptococcus mutans biofilm formation in vitro.

OBJECTIVES: The aim of this study was to determine the in vitro microbiological performances of a lactose-modified chitosan (Chitlac) coating inside which silver nanoparticles were embedded (Chitlac-nAg) for BisGMA/TEGDMA methacrylic specimens. METHODS: Different concentrations of nAg inside Chitlac coating were tested (1 mM, 2 mM, 5 mM). Specimen surface was analyzed by means of field-emission scanning electron microscopy (FEISEM) and energy-dispersive X-ray spectroscopy (EDS). A 48 h monospecific Streptococcus mutans biofilm was developed over the specimen surfaces using a modified drip-flow bioreactor; adherent viable biomass was assessed by MTT test and biofilm was imaged by confocal laser-scanning microscopy (CLSM). RESULTS: The presence of finely dispersed nanoparticles inside the Chitlac coating was confirmed by FEISEM and EDS analysis. All nanoparticles were embedded in the Chitlac coating layer. Chitlac-nAg coatings were able to significantly decrease biofilm formation depending on the nAg concentration, reaching a -80% viable biomass decrease when the 5 mM nAg-Chitlac group was confronted to non-coated control specimens. CLSM analysis did not provide evidence of a contact-killing activity, however the antibacterial Chitlac-nAg coating was able to alter biofilm morphology preventing the development of mature biofilm structures. CONCLUSIONS: The microbiological model applied in this study helped in assessing the antibacterial properties of a coating designed for methacrylate surfaces. CLINICAL SIGNIFICANCE: A microbiological model based on a bioreactor-grown biofilm is useful for preliminary in vitro tests of dental materials. In translational terms, an antibacterial nanocomposite coating based on Chitlac-nAg and designed to be applied to methacrylic surfaces may be a promising way to obtain dental materials able to actively prevent secondary caries.