Level of Anxiety Caused by the Coronavirus (COVID-19) Pandemic among Dentists in Poland.

Background and Objectives: The early information on both the speed and high morbidity rate and, above all, mortality triggered the symptoms of COVID-19-related panic and anxiety. Dentists were listed in the top five professions with the highest risk of transmission of the virus. The aim of the present study was to investigate the correlation between the fear level of COVID-19 and sociodemographic variables in Polish dentists. Materials and Methods: A cross-sectional study was conducted via an online survey questionnaire with seven statements in the COVID-19 Fear Scale (FCV-19S). The online questionnaire was completed by 356 dentists. The SPSS and PQStat were used to analyze, validate, and assess correlations and logistic regression. Results: In the studied population of dentists, the perceived level of anxiety associated with COVID-19 should be considered relatively low. When the respondents had children, lived with the elderly, or looked after them, the observed level of anxiety was higher, and physical symptoms, such as sweating palms and increased heart rate, occurred. Conclusions: Studies concerning the anxiety level related to COVID-19 carried out among Polish dentists ascertained that the tested level of anxiety among dentists was relatively low. The COVID-19 Fear Scale (FCV-19S) adjusted to the Polish language requirements is a reliable tool that can be used effectively for analyzing the impact of any pandemic on the Polish-speaking population.

Knowledge of antibiotics and antimicrobial resistance amongst final year dental students of Polish medical schools-A cross-sectional study.

INTRODUCTION: Antimicrobial resistance has been one of the biggest global concerns. Dentists constitute an important group of antibiotic prescribers, and it was shown that their therapeutic decisions are not always rational. In this paper, we present knowledge of antibiotics prescription rules and antimicrobial resistance amongst graduating dentistry students from all dentistry faculties of medical universities in Poland, who will soon join the group of antibiotics prescribers. MATERIALS AND METHODS: A questionnaire consisting of 28 questions was developed. The survey was conducted in May-June 2015. RESULTS: The study group comprised a total of 752 students. About 54% expressed the opinion that dentists overprescribe antibiotics. One-tenth thought that they can be used for the treatment of flu (7%) and common cold (11%). Respondents pointed to amoxicillin (46%) and clindamycin (44%) as the first-choice treatment of dentoalveolar abscess, if medically indicated. More than half of the students (58%) suggested using doxycycline and metronidazole in aggressive periodontitis in an individual allergic to penicillin. The vast majority of students (97%) indicated that penicillins and cephalosporins were suitable for treatment of dental infections in pregnant women. The majority of participants (82%) said that rheumatic disease, chronic immunosuppression, chronic kidney failure and a history of infective endocarditis required a prophylactic administration of antibiotics before or during endodontic treatment. CONCLUSIONS: The research showed variable levels of understanding of antibiotics use amongst dental students in medical universities in Poland. Our results emphasise the need to educate dental students further regarding antibiotics and risks related to antibiotic misuse, especially in dental practice.

Effectiveness of repeated photodynamic therapy in the elimination of intracanal Enterococcus faecalis biofilm: an in vitro study.

The study aimed to investigate the effectiveness of photodynamic therapy in the elimination of intracanal Enterococcus faecalis biofilm and to analyse how a repeated light irradiation, replenishment of oxygen and photosensitiser affect the results of the photodynamic disinfecting protocol. After chemomechanical preparation, 46 single-rooted human teeth were infected with a clinical strain of E. faecalis and incubated for a week in microaerobic conditions. The experimental procedures included groups of single application of photodynamic therapy, two cycles of PDT, irrigation with 5.25% NaOCl solution and negative and positive control. The number of residing bacterial colonies in the root canals was determined based on the CFU/ml method. In the group of preparations irrigated with NaOCl, bacterial colonies were not observed. A single PDT eliminated 45% of the initial CFU/ml. Repeated PDT eradicated 95% of the intracanal bacterial biofilm. Photodynamic therapy has a high potential for the elimination of E. faecalis biofilm. There is a safe therapeutic window where photoinduced disinfection can be used as an adjuvant to conventional endodontic treatment, which remains the most effective.

An in vitro evaluation of the effect of fluoride products on white spot lesion remineralization.

PURPOSE: To compare the effect of combinations of fluoride (F) products on remineralization of caries-like lesions. METHODS: Demineralized human enamel specimens were assessed by surface microhardness (SMH), stratified and allocated to five treatments groups: (1) Toothpaste containing 1% nano hydroxyapatite (HAP) + 1,450 ppm F; (2) Tooth mousse containing 10% casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) + 900 ppm F plus F toothpaste (1,450 ppm F as NaF); (3) F varnish containing 22,600 ppm F plus F toothpaste (1,450 ppm F as NaF); (4) F toothpaste (1,450 ppm F as NaF); and (5) placebo--distilled water (P). Each group was treated in a 21-day pH-cycling model. Groups 1, 4 and 5 were treated 2x/day. In Group 3, the tooth mousse was administered 1x/day plus 2x/day F toothpaste treatment. In Group 4, F varnish was administered 1x/week plus 2x/day treatment with F toothpaste. After cycling, SMH was re-measured and cross-sectional microhardness measurements were taken. RESULTS: Groups 1-4 produced significant rehardening of enamel. In the superficial layer (25-50 µm deep) significantly higher mineralization (up to 83%, by Volume (V), P < 0.0001) was achieved for Groups 2 and 3. In the area of 75-100 µm deep, the highest mineralization was observed for Groups 1 and 4 (V% = 68-83%).

The effect of nano-hydroxyapatite toothpaste on enamel surface remineralization. An in vitro study.

PURPOSE: To compare, in vitro, the surface remineralization effect of two fluoride dentifrices. METHODS: 90 human enamel specimens, embedded in cylindrical acrylic blocks, washed and polished, served as a study material. The specimens were randomly assigned in equal numbers to the three groups (two test and one control). Initially the microhardness of the enamel surface (SMH) was assessed by Vickers method, while a profilometer was used to evaluate the surface roughness (Ra value). The enamel specimens were subjected to the preliminary demineralization, simulating the initial carious lesion formation. Subsequently, mean SMH and Ra values were re-assessed. Upon demineralization, one half of each specimen was covered with a protective varnish. The exposed fragment underwent the 3-week cycle of pH changes, according to the protocol. The groups were as follows: NHAPF group--toothpaste containing nanohydroxyapatite (nano HAP) and 1,450 ppm F; F group--toothpaste containing 1,450 ppm; and P group (placebo)--distilled water. Upon completion of the treatment period, the enamel microhardness and roughness profile were re-measured. RESULTS: The demineralization procedure resulted in statistically significant reduction of SMH level in all the groups, and the mean post demineralization values were in the range of 49.7 VHN to 51.2 VHN. Remineralization therapies led to statistically significant increase of enamel SMH value (P < 0.0001). None of the groups reached their original baseline level of SMH following the remineralization therapy.

Prevalence of Dental Erosive Wear and Possible Risk Factors among Adolescents and Adults in Poland - A National Survey.

PURPOSE: To investigate the prevalence and severity of erosive tooth wear (ETW) and evaluate the determinants of ETW among adolescents and adults in Poland. MATERIALS AND METHODS: The study covered three age groups of patients: 15 years old, 18 years old, and adults aged 35-44 years. Calibrated examiners measured ETW according to the Basic Erosive Wear Examination (BEWE) scoring system in 6091 patients. The clinical examination of patients was preceded by a socio-medical study based on a questionnaire consisting of items identifying potential risk factors for ETW. RESULTS: In all age groups, erosive lesions were most common in the form of initial enamel damage; more advanced lesions (BEWE 2 and 3) were rarely observed among 15-year-olds, while in the group of older adolescents and adults, the percentages were 13% and 20%, respectively. Acidic diet, gender, level of education, and medical conditions were statistically significantly associated with ETW in the examined population. The analysis showed that, depending on age, multiple and statistically significant risk factors for ETW become most apparent in the 35-44 age group, especially with regard to general health. This suggests that the long-term impact of factors and their cumulative effects are critical to the development of ETW. CONCLUSIONS: This is the first large, representative study of ETW in Central and Eastern Europe among adolescents and adults, which indicates the relatively rare occurrence and severity of erosive lesions. The present findings support other longitudinal studies supporting the use of the BEWE system as a valuable standard for assessing erosive lesions and related risk factors among different populations at different ages.

Evaluation of Salivary Biomarkers and Spirometry for Diagnosing COPD in Non-Smokers and Smokers of Polish Origin.

Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory condition with global implications. Accurate and timely diagnosis is critical; however, traditional diagnostic methods (based on spirometry) show limitations, prompting the search for predictive biomarkers and modern diagnostic techniques. This study explored the validation of COPD-related biomarkers (C-reactive protein, procalcitonin, neutrophil elastase, and alpha-1 antitrypsin) in saliva. A diverse cohort, including healthy non-smokers, healthy smokers, and COPD patients of Polish origin, underwent spirometry and marker analysis. The data correlated with clinical factors, revealing noteworthy relations. Firstly, salivary biomarker levels were compared with serum concentrations, demonstrating notable positive or negative correlations, depending on the factor. Further analysis within healthy individuals revealed associations between biomarker levels, spirometry, and clinical characteristics such as age, sex, and BMI. Next, COPD patients exhibited an enhanced concentration of biomarkers compared to healthy groups. Finally, the study introduced a breathing assessment survey, unveiling significant associations between self-perceived breathing and spirometric and tested parameters. Outcomes emphasized the relevance of subjective experiences in COPD research. In conclusion, this research underscored the potential of salivary biomarkers as diagnostic tools for COPD, offering a non-invasive and accessible alternative to traditional methods. The findings paved the way for improved modern diagnostic approaches.

[Evaluation of biocidal properties of silver nanoparticles against cariogenic bacteria]. / Ocena bakteriobójczej aktywnosci koloidalnego roztworu nanoczastek srebra w stosunku do bakterii próchnicotwórczych.

INTRODUCTION: Antimicrobial properties of silver nanoparticles (SNP's) have been recentl well evaluated, and now are being considered as excellent candidates for therapeutic purposes. It is confirmed, that various solutions of colloidal SNP's possess significant antibacterial properties against such species as: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa even at low concentrations, although there have been so far only a few researches evaluating antimicrobial activity of SNP's against cariogenic bacteria: Streptococcus mutans, Streptococcus salivarius and Streptococcus mitis responsible for initiation of dental carries. Tooth decay is infectious disease an worldwide, which may occur in patients of every age. Nanotechnology creates a new approach of designing of medical devices preventing or reducing bacterial colonization. METHODS: Colloidal silver solution (CSS) of concentration 350 ppm was used in this research. Nanoparticles size, shape and solution stability were evaluated. 16 strains of cariogenic bacteria, 4 isolates of each species: S. mutans, S. salivarius, S. sanguinis and S, mitis were obtained from plaque swabs of 7 patients treated for dental carries at Department of Conservative Dentistry, Medical University of Warsaw. MIC and MBC values for CSS's were evaluated. RESULTS: CSS used in this research is of good stability. No agglomeration or coalescence was observed during 24 hours of experiment. Silver nanoparticles were of round shape and had mean size of 67 nm. MIC values were: 12-25 ppm for S. salivarius, 25 ppm for S. sanguinis, 50-100 ppm for S. mitis and 50 ppm for S. mutans, while MBC values after 1 hour of bacterial contact with nanoparticles were 200-350 ppm for all cariogenic bacterial species. After 24 hours of contact MBC values were: 25-50 ppm for S. salivarius and S. sanguinis, 100-200 ppm for S. mitis and 200 ppmfor S. mutans. CONCLUSIONS: Antimicrobial properties of CSS depend on nanoparticles concentration and interaction time with bacteria. The susceptibility of cariogenic oral streptococci to silver nanoparticles is diversified. Sufficient concentration which inhibited all cariogenic bacteria in our research was 200 ppm after long (24 hours) period of silver nanoparticles interaction with bacteria.

Oral changes in patients with psoriasis.

Psoriasis is one of the most frequent skin diseases. The cause of psoriasis is not fully expained as there are many factors (infectious, traumatic, hormonal, and chemical) that may play a role in the manifestation of its symptoms. One of the factors that may contribute to the appearance of psoriatic lesions may be the lesions in the oral cavity. The occurrence of lesions in the oral cavity is defined as rare, what can be explained by their nonspecific clinical image, and also by the possibility of being overlooked. Most characteristic symptoms of psoriasis occurring in the oral cavity are the geographic tongue and fissured tongue. It is also believed that there is a correlation between psoriasis and oral health- the periodontal and teeth condition as well as changes in saliva secretion. The psoriasis arthritis changes can also affect temporomandibular joint and impair the function of stomatognathic system. Because of these reports, cooperation of dermatologists and dentists in psoriasis care seems to be necessary.

Effect of the Abutment Rigidity on the Wear Resistance of a Lithium Disilicate Glass Ceramic: An In Vitro Study.

Lithium disilicate (LDS) glass ceramics are among the most common biomaterials in conservative dentistry and prosthodontics, and their wear behavior is of paramount clinical interest. An innovative in vitro model is presented, which employs CAD/CAM technology to simulate the periodontal ligament and alveolar bone. The model aims to evaluate the effect of the abutment rigidity on the wear resistance of the LDS glass ceramic. Two experimental groups (LDS restorations supported by dental implants, named LDS-on-Implant, or by hybrid ceramic tooth replicas with artificial periodontal ligament, named LDS-on-Tooth-Replica) and a control group (LDS-Cylinders) were compared. Fifteen samples (n = 15) were fabricated for each group and subjected to testing, with LDS antagonistic cusps opposing them over 120,000 cycles using a dual axis chewing simulator. Wear resistance was analyzed by measuring the vertical wear depth (mm) and the volume loss (mm3) on each LDS sample, as well as the linear antagonist wear (mm) on LDS cusps. Mean values were calculated for LDS-Cylinders (0.186 mm, 0.322 mm3, 0.220 mm, respectively), LDS-on-Implant (0.128 mm, 0.166 mm3, 0.199 mm, respectively), and LDS-on-Tooth-Replica (0.098 mm, 0.107 mm3, 0.172 mm, respectively) and compared using one-way-ANOVA and Tukey's tests. The level of significance was set at 0.05 in all tests. Wear facets were inspected under a scanning electron microscope. Data analysis revealed that abutment rigidity was able to significantly affect the wear pattern of LDS, which seems to be more intense on rigid implant-abutment supports compared to resilient teeth replicas with artificial periodontal ligament.

A novel power toothbrush with multi-directional, triple zone cleaning technology.

PURPOSE: Numerous laboratory and clinical studies have proven that certain power toothbrush technologies are more effective in removal of dental plaque and reduction of gingivitis than regular manual toothbrushes. Regardless of this evidence, there is still a large group of individuals who prefer the experience of a manual-like toothbrush. Recently a novel multi-directional power brush has been developed as an alternative for those people who favor the traditional size and shape of a manual toothbrush and prefer the manual brushing technique, but would benefit from the greater cleaning efficiency of the power brush. METHODS: This unique multi-directional power toothbrush with triple-zone cleaning technology has been tested in multiple clinical trials. This special issue introduces the technical features of the brush and presents four clinical investigations conducted with this power toothbrush versus manual and sonic controls. RESULTS: The studies described in this issue demonstrate the superior efficacy of the multi-directional brush in plaque and gingivitis reduction relative to control brushes, even in the hard-to-reach interdental spaces and marginal areas.

A 4-week clinical comparison of a novel multi-directional power brush to a manual toothbrush in the reduction of gingivitis and plaque.

PURPOSE: To evaluate the efficacy of a novel multi-directional power toothbrush in reducing plaque and gingivitis relative to a standard manual toothbrush control. METHODS: This 4-week, randomized and controlled, single-center, parallel group, examiner-blinded clinical study enrolled adults with mild-to-moderate gingivitis. At baseline, pre-treatment gingivitis and plaque levels were assessed via the Lobene Modified Gingival Index (MGI), the Gingival Bleeding Index (GBI), and the Rustogi Modified Navy Plaque Index (RMNPI). Subjects qualifying were assigned randomly to one of two toothbrush groups: a novel multi-directional power toothbrush (Oral-B Professional Deep Sweep TRICLEAN 1000, also marketed as Oral-B TriZone) or a standard soft manual control toothbrush. Aside from a supervised brushing at baseline on-site, subjects brushed at home twice daily with their assigned test brush. After 1 week, subjects returned for RMNPI plaque evaluations. At Week 4, subjects were again recalled to evaluate toothbrush efficacy, and received MGI and GBI gingivitis and RMNPI plaque evaluations. RESULTS: 119 evaluable subjects completed the study. Both the novel power and manual control toothbrushes yielded statistically significant (P < 0.001) mean plaque reductions compared to baseline at Weeks 1 and 4 (except Week 1 manual brush gingival margin) and significant mean MGI and GBI gingivitis reductions (P < 0.001). Comparing the relative effectiveness of the test brushes, the novel multi-directional power brush produced significantly superior anti-gingivitis and anti-plaque reductions compared to pre-treatment relative to the manual control brush in every analysis at both time points. The Week 4 adjusted mean relative reductions favoring the multi-directional power brush were 3 and 1.49 times greater for whole mouth MGI and GBI, respectively (P < 0.001); and were 2.1, 4.7 and 2 times greater for the RMNPI whole mouth, gingival margin and interproximal regions, respectively (P < 0.001). Both toothbrushes were well-tolerated.

Influence of Instrument Lubrication on Properties of Dental Composites.

Resin composites are one of the most commonly used materials in restorative dentistry. To improve their handling and facilitate restoration sculpting, clinicians began to lubricate modeling instruments with various substances like alcohol, unfilled resins, or even bonding agents. Although the technique is commonly present in daily clinical practice, it has not been precisely described in the literature and both application methods and lubricating materials vary across the available studies. This study aims to summarize the currently available knowledge about influence of instrument lubrication on properties of dental composites. Literature selection was conducted within MEDLINE, SCOPUS, and EBSCO databases. Instrument lubrication seems not to be indifferent for composite mechanical and optical properties. Moreover, various lubricants can differently affect the composite material, so the choice of lubricating agent should be deliberate and cautious. Available in vitro studies suggest possible incorporation of lubricant into the composite structure. Unfilled resins based on bisphenol A-glycidyl methacrylate (Bis-GMA) seem to be the best choice for the lubricant, as bonding agents containing hydrophilic molecules and alcohols carry a bigger risk of altering the composite properties. Further research is necessary to evaluate lubricants' influence in clinical practice conditions.

Dental Implant Healing Screws as Temporary Oral Drug Delivery Systems for Decrease of Infections in the Area of the Head and Neck.

Background: Periimplantitis is continuously one of major threats for the uneventful functioning of dental implants. Current approaches of drug delivery systems are being more commonly implemented into oral- and maxillofacial biomaterials in order to decrease the risk of implant failure due to bacterial infection. Silver nanoparticles and their compounds have been proven in eradicating oral bacteria responsible for peri-implant infections. Nevertheless, their evaluation as coating for implant abutments has not been extensively evaluated so far. This article describes a novel coating consisting of zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs). This coating was used to modify healing abutments that could be used as drug delivery systems in oral implantology. Materials and Method: Nanoparticles with a ZnO + 0.1% Ag composition were produced by microwave solvothermal synthesis and then incorporated into the surface of titanium healing abutments by high-power ultrasonic deposition. Surface morphology, roughness, wettability were evaluated. Ability of biofilm formation inhibition was tested against S. mutans, S. oralis, S. aureus and E. coli. Results: ZnO+0.1%Ag NPs were sufficiently deposed on the surface of the abutments creating nanostructured coating which increased surface roughness and decreased wettability. Modified abutments significantly decreased bacterial biofilm formation. Bacteria present in SEM studies were unlikely to settle and replicate on the experimental abutments as their cells were rounded, insufficiently spread on the surface and covered with released NPs. Conclusion: Experimental nanostructured abutments were easily manufactured by high-power ultrasonic deposition and provided significant antibacterial properties. Such biomaterials could be used as temporary drug delivery abutments for prevention and treatment of intra- and extraoral peri-implant infections in the area of the head and neck.

[Pasta quality in view of its elemental composition]. / Jakosc makaronów w swietle ich skladu pierwiastkowego.

Concentrations of iron, zinc, copper and manganese were determined in 13 different kinds of pasta available in sale. The concentrations of chemical elements were analysed, after wet mineralization, by flame atomic absorption spectrometry - AAS with deuterium background correction. Reliability of the procedure was checked by analysis of certified reference materials. The average concentrations (mg/100 g) of minerals in pasta were as follows: 16.3 for calcium; 159 for potassium; 1.93 for iron and 1.35 for zinc. These measurements allowed to estimate the realisation of the recommended daily intake of bioelements with the analysed products for an adult person. The highest percentage of realisation was estimated for wholewheat pasta. Statistical analysis has shown a strong influence of the flour type (wholemeal, semolina, wheat) used in pasta production on elements concentrations.

A comparison of the remineralizing potential of dental restorative materials by analyzing their fluoride release profiles.

BACKGROUND: The accessibility of the remineralizing ions in teeth's environment is essential for their incorporation into caries-affected dentin. Novel bioglass-reinforced materials capable of releasing fluoride, calcium and phosphates may be particularly useful in the tissue remineralization process. A novel restorative material, ACTIVA BioActive-Restorative (Pulpdent Corp., Watertown, USA), is a hydrophilic resin-modified glassionomer cement (RMGIC) enriched with bioglass particles and fortified with a patented rubberized polymer resin. Its application in restorative dentistry may be significant, promoting remineralization of carious lesions. OBJECTIVES: The aim of the study was to compare the fluoride ion release profiles from a bioglass-reinforced RMGIC, a conventional glass-ionomer cement (GIC) and a nanohybrid restorative polymer resin. MATERIAL AND METHODS: The quantity of fluoride ions released from ACTIVA, Ketac Molar Quick Aplicap and Tetric EvoCeram was assessed using a fluoride-specific electrode. The surface characteristics of the preand post-experimental specimens were studied using a scanning electron microscope (SEM) and confocal microscope. An X-ray powder diffraction (XRD) analysis was additionally used to examine the chemical compositions of the dental materials. RESULTS: The greatest quantity of fluoride ions was freed from the GIC specimens (20.698-54.118 ppm), followed by the bioglass-reinforced RMGIC (from 1.236 to 15.552 ppm) and nanohybrid polymer resin (0.370-1.148 ppm). The pre-experimental specimens of the bioglass-reinforced RMGIC were porous, while the post-experimental specimens were smoother with visible micro-cracks. The XRD analysis of the bioglass particles confirmed that the material was composed mainly of fluoride (27.70 mass%), silicon (15.62 mass%), aluminum (5.91 mass%), and calcium (5.40 mass%). CONCLUSIONS: The fluoride ion release profile of ACTIVA was lower than the GIC Keta Molar Quick Aplicap, but significantly higher than the nanohybrid restorative polymer resin Tetric EvoCeram.

Quantitative assessment of the rotation and twist of the left ventricle during dobutamine stress echocardiography: a comparison of patients with and without significant coronary artery disease.

BACKGROUND: The rotation and twist of the left ventricle (LV) have been comprehensively evaluated at rest. However, little is known about rotational mechanics during dobutamine stress echocardiography (DSE). AIMS: We aimed to quantify and compare the basal and apical rotation and twist of the LV at rest as well as at the peak and recovery stages of DSE in patients with and without coronary artery disease (CAD). METHODS: We enrolled 91 patients, including 48 patients with CAD and 43 patients without CAD (mean [SD] age, 62 [9] years and 61 [10] years, respectively). Coronary artery disease was defined as the presence of stenoses of 50% or more in the left main coronary artery and/or stenoses of 70% or more in other epicardial arteries. Rotation was measured by 2­dimensional speckle­tracking echocardiography, and twist was calculated as the difference between the basal and apical rotation. RESULTS: Neither rotation nor twist differed between patients with and without CAD at rest, although apical rotation was significantly greater in the CAD group at peak DSE (mean [SD], 5.43° [3.45°] vs 3.71° [3.52°], P = 0.01) and at recovery (mean [SD], 5.05° [3.65°] vs 2.87° [2.73°], P <0.01). On the contrary, the absolute value for basal rotation at recovery was higher in patients without CAD (mean [SD], 3.87° [3.37°] vs 2.63° [2.43°], P = 0.03). In both groups, the rotation and twist did not change significantly during the dobutamine challenge. CONCLUSIONS: During DSE, we observed differences in LV rotation between patients with and without CAD, revealing the effect of ischemia on deformation parameters.

Nanoparticles And Human Saliva: A Step Towards Drug Delivery Systems For Dental And Craniofacial Biomaterials.

AIM: The aims of this study were to investigate new nano-formulations based on ZnO and Ag nanoparticle (NP) compounds when used against clinical strains of oral gram-positive and gram-negative bacteria, and to examine the stability and behaviour of nano-formulation mixtures in saliva based on different compositions of Ag NPs, ZnO NPs and ZnO+x·Ag NPs. Methods: ZnO NPs with and without nanosilver were obtained by microwave solvothermal synthesis. Then, antibacterial activity was evaluated against bacteria isolated from human saliva. Behavior and nanoparticle solutions were evaluated in human saliva and control (artificial saliva and deionized water). Results were statistically compared. RESULTS: The NP mixtures had an average size of 30±3 nm, while the commercial Ag NPs had an average size of 55±5 nm. The suspensions displayed differing antibacterial activities and kinetics of destabilisation processes, depending on NPs composition and fluid types. CONCLUSION: The present study showed that all NPs suspensions displayed significant destabilisation and high destabilisation over the 24 h of the analyses. The agglomeration processes of NPs in human saliva can be reversible.

The effect of strip, tray and office peroxide bleaching systems on enamel surfaces in vitro.

UNLABELLED: Improvement of the appearance of teeth by whitening systems is one of the goals of modern esthetic dentistry. Vital tooth bleaching is administered in a variety of forms including trays, strips and paint-on gels. The concentrations and conditions of bleaching systems vary considerably between these treatment forms. OBJECTIVES: This study compared surface changes associated with exposure of human premolar teeth to topical cycling treatments with three different bleaching systems: Opalescence X-Tra Boost (OPXB), Opalescence 20% PF (OP20PF) and Crest Whitestrips Supreme (CWSS), respectively. METHODS: Extracted human premolars were prepared in Durabase blocks and measured for tooth color, surface microhardness and roughness. Teeth were cycled in a regimen including a pre-test period, test bleaching treatment and 7 days post-bleach period. Bleaching was segmented to 0 h for untreated control group (UC); 42 h for CWSS, 42 h for OP20PF and 45 min with OPXB. Following treatment specimens were re-measured as before. RESULTS: Bleaching treatments produced significant tooth lightening (yellow reduction). Hardness of enamel specimens from control and bleaching groups were unchanged during cycling: Delta Vickers hardness number (VHN): UC (18+/-11S.D.) a; CWSS (7.0+/-29nsd) a; OP20PF (19+/-15S.D.) a; OPXB (25+/-13S.D.) a (nsd = non-significant difference post-cycle-treat vs. initial Student's t; ANOVA p<0.05 a not equal b between group comparison post-treat). With respect to surface roughness, two-dimensional analysis showed no changes with bleaching: DeltaR(a) (roughness) 2D = UC (0.06+/-0.06nsd) a; CWSS (0.02+/-0.07nsd) a; OP20PF (-0.14+/-0.08nsd) a; OPXB (0.00+/-0.12nsd) a. CONCLUSION: Office administered, prescribed and OTC/prescribed bleaching systems were demonstrated as similarly safe to enamel surfaces including maintenance of both hardness and roughness in vitro.

Nanomaterials in dentistry: a cornerstone or a black box?

AIM: The studies on tooth structure provided basis for nanotechnology-based dental treatment approaches known as nanodentistry which aims at detection and treatment of oral pathologies, such as dental caries and periodontal diseases, insufficiently being treated by conventional materials or drugs. This review aims at defining the role of nanodentistry in the medical area, its potential and hazards. MATERIALS & METHODS: To validate these issues, current literature on nanomaterials for dental applications was critically reviewed. RESULTS: Nanomaterials for teeth restoration, bone regeneration and oral implantology exhibit better mechanical properties and provide more efficient esthetic outcome. However, still little is known about influence of long-term function of such biomaterials in the living organism. CONCLUSION: As application of nanomaterials in industry and medical-related sciences is still expanding, more information is needed on how such nano-dental materials may interfere with oral cavity, GI tract and general health.