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Introduction Marginal seal or adequate marginal adaptation of material along the cavity walls should be able to prevent leakage of tissue fluid and consequently bacterial microleakage, terefore, it is considered as significant factor for long term success of endodontic treatment. The aim of this work was to test the marginal microleakage of newly synthesized nanostructured biomaterials based on calcium aluminate, calcium silicate and MTA with a dye penetration test after application the material to the interradicular perforations of extracted teeth. Material and method The study included 48 extracted human maxillary and mandibular molars. Newly synthesized nanostructured materials were tested: material based on calcium aluminate, calcium silicate. Commercial calcium silicate cement (MTA Angelus, Londrina, Brazil) was used as a control material. Marginal microleakage was examined with a dye penetration test six months after application of the material in experimentally prepared interradicular perforations on extracted human molars. Penetration depth measurement was analyzed with a binocular magnifier (Leica DM 500, Leica Byosistems). Results are expressed in millimeters and statistically processed by applying the analysis of variance for repeated measurements with the Sidak test. Results The lowest average penetration (mm) was for MTA (1.40 ± 0.63 mm), and the highest for Ca aluminates (2.10 ± 0.63 mm), while for calcium silicates an average color penetration of 1.73 ± 0, 67mm was recorded. By testing intergroup differences in color penetration between groups, a statistically significant difference between MTA and Ca aluminate was obtained using Sidak's test (t = -0.693; p = 0.036). No statistically significant difference was recorded between MTA and Ca silicate, nor was there a statistically significant difference between Ca aluminate and Ca silicate. Conclusion The lowest marginal microleakage, the best marginal sealing, was recorded with the MTA material. The microleakage of calcium aluminate-based materials was significantly higher compared to calcium silicate and MTA.

Introduction In addition to good biological properties, biomaterials should also possess appropriate physical properties in order to provide stability and longevity at the place of application. The aim of this work was to evaluate physical properties of an experimental nanostructured material based on calcium aluminate (CAL) and calcium silicate (CS). Material and method The research used nanostructured calcium aluminate synthesized by the hydrothermal solgel method from the individual components of calcium aluminate (CaO·Al2 O3 ), calcite (CaCO3 ) and barium sulfate (BaSO4 ) as an X-ray contrast agent and calcium silicate (CS). The prepared material was placed in plastic molds with a diameter of 5 ± 0.1 mm and a height of 2 ± 0.1 mm. After setting time, the materials were left in an incubator at 37°C for 24 hours, and then they were removed from the mold and absorption and solubility of the materials was calculated. MTA (Angelus Londrina, Brazil) was used as a control material. Results The lowest material solubility was recorded with MTA (0.255 mg/mm3 ), followed by calcium silicate (0.267 mg/mm3 ), and the highest with calcium aluminate (0.725 mg/mm3 ). The difference was statistically significant between calcium aluminate and MTA (p = 0.001901) and between calcium aluminate and calcium silicate (p = 0.002550). After 28 days in deionized water, the lowest water sorption was recorded with MTA (0.347 mg/mm3 ), followed by calcium silicate (0.357 mg/mm3 ), and the highest water sorption was measured with calcium aluminate (0.474 mg/mm3 ). Statistically significant differences were observed between calcium aluminate and MTA (p = 0.000283) and between calcium aluminate and calcium silicate (p = 0.001576). Conclusion Material solubility and water absorption of calcium aluminate-based nanostructured material was significantly higher compared to calcium silicate (CS) and MTA.

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Introduction ALBO-HA (Vinca, Serbia) is new nanostructured calcium aluminate cement, synthesized as a potential alternative to mineral trioxide aggregate (MTA). The purpose of this study was to compare the periapical tissue response to new nanostructured calcium aluminate cement ALBO-HA with white MTA (MTA Angelus, Londrina, Brasil) as root-filling material into the root canal of sheep' s teeth. Material and methods Sixteen mandibular incisors from two 24-month-old sheep were used. Root canals were pre pared and filled with ALBO-HA (group 1) or MTA (group 2) (eight teeth per group in each sheep). After four weeks the animals were sacrificed, teeth with surrounding tissue removed, and histologically processed. The sections were analyzed for determination of scores of the following parameters: periapical inflammatory infiltrate, newly mineralized apically formed tissue, apical periodontal ligament space thickness and resorption of dentin, cementum and bone. Data were analyzed statistically (a=0.05) using Mann-Whitney U test. Results Slight inflammatory infiltrate was observed in 75.0% and 62.5% of samples in the group 1 and group 2, respectively (p>0.05). Partial newly mineralized apically formed tissue was found in 75.0% of samples in the group 1, and 87.5% of samples in group 2 (p>0.05). No significant difference was noted for periodontal ligament space thickness (p>0.05). Resorption of dentin, cementum or bone was not observed. Conclusion ALBO-HA and white MTA Angelus had a similar effect on inflammation, newly mineralized apical tissue formation and thickness of periodontal ligament space after root canal filling under the present experimental conditions.

Introduction/Objective. of this study is to use scanning electron microscopy (SEM) analysis to examine surfaces of new and same sets of Ni-Ti instruments after canal preparations, to check their suspectability to corrosion. Methods. In this study, we used five different endodontic Ni-Ti instruments: K3, Mtwo, ProTaper Universal, HyFlex and BioRaCe. Instruments were analyzed before and after preparation of canals of different curvature, using SEM (150–2000 ×). Results. Corrosion of the working part was observed in 5.5% of new Ni-Ti instruments of the K3 system (apical and middle segment), in 5.5% of Mtwo instruments (apical third), and in 11.1% of ProTaper Universal systems (apical and middle third). Corrosion was not observed on the new instruments of the HyFlex and BioRaCe kits. After instrumentation, disinfection, and sterilization, corrosion was observed in all sets of K3 and ProTaper Universal systems and in all HyFlex instruments of the first group. Corrosion was observed in the HyFlex system in the second group in 16.7% of instruments (apical and middle third) and in the third 83.3% in the apical and 66.7% in the middle segment. In the Mtwo set, corrosion was observed in 16.7% of instruments in the first (apical and middle third), in the second group in 33.3% of instruments in the apical part and 50% in the middle third, while in the third group, corrosion was observed in 16.7% of instruments in the middle third of instruments. Conclusion. Rotary Ni-Ti instruments K3 and ProTaper Universal are susceptible to corrosion in a very high percentage. Ni-Ti systems with post-heat treatment of the working part (HyFlex) are somewhat more resistant to corrosion, while in Ni-Ti systems with electropolished surface (BioRaCe), corrosion is not observed.

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Numerous technological solutions in recent years have significantly improved the cleaning and shaping of canals and made canal instrumentation simpler, more efficient and safer. Significantly faster and less stressful canal instrumentation for the therapist is enabled by the specific design of the file working part and a special thermal modification of NiTi alloy with a change in the movement dynamics of the file in the canal. Research has shown that the problem of cyclic fatigue and torsional stress of the file during canal preparation can be solved by changing usual continuous rotation of the file. Dental technology has introduced the technique of reciprocal movements as an alternative to full file rotation. This change in file rotation direction during instrumentation, based on the technique of balanced forces, significantly reduces contact surface with the canal wall, eliminates the effect of screwing, extends the life of the file and further increases safety of instrumentation of different canal systems. An important advantage of changing the usual dynamics of file movements is that the concept of reciprocal movements is based on the use of only one file, which in addition to shortening treatment time also makes this intervention safer and with significantly lower percentage of defects and fractures of NiTi files. The aim of this paper was to present the concept of canal instrumentation with NiTi files with reciprocal movements as well as development, properties and possibility of application of these files in different clinical situations.

Introduction/Objective. Lead exposure represents one of the most important factors that affect the general health, including oral health and it is associated with enamel and dentin tooth defects. The aim of this paper was to determine expression of the fibronectin in the pulp of rats with experimentally induced diabetes mellitus (DM), after lead exposure, by using immunohistochemical analysis. Methods. The study was conducted on 42 rats of Wistar strain. Intoxication of rats with lead-acetate was done via drinking water ad libitum. The first group (Exp_14) consisted of 16 rats, which received lead in water for 14 days, the second group (Exp_30) consisted of 16 rats which received lead in water for 30 days at the same concentration (1500 ppm), while the control consisted of 10 healthy rats. Groups Exp_14 and Exp_30 were induced into DM, by using the Alloxan intraperitoneally. Pathohistological and immunohistochemical analysis determined fibronectin expression in pulp, odontoblasts, predentin and dentine of the teeth. Results. High diffuse positivity of fibronectin in group Exp_14 was noticed in 63.6% of rats, in group Exp_30 in 24% of rats, while in the control group it was noticed in 50% of rats. There was no statistically significant difference in the expression of fibronectin between the examined groups. Conclusion. Lead intoxication through drinking water, for a period of 14 and 30 days, had effect on the expression of fibronectin in the pulp, odontoblasts, predentin and dentin of the teeth of animals experimentally induced DM.

In this paper viruses are considered as very efficient nano-machines that produce numerous copies of them. Observing these nano-architectures, the question arises: which molecular forces and processes make up the set of such structures, given that they are extremely inspiring for development of new technologies at the nano level. There is a need for deep understanding of individual molecular building blocks and their structures, properties of their assemblies and dynamic behavior.

More certain therapeutic and significantly facilitated solution of everyday endodontic problems are provided by the introduction of NiTi rotary files in endodontic practice and their proper application. However, their widespread use has caused more and more frequent fractures and has become a significant frustrating factor that diminishes their numerous benefits. Torsional stress and cyclic fatigue are the main reasons for the occurrence of a fracture, and the frequency of NiTi file fractures is exactly proportional to the degree of bending of the canal, knowledge of the features of the file, ie. the skill and expertise of the therapist. The most dominant factor for the occurrence of fractures is the dentist who, in addition to manual dexterity, must have a good knowledge of the anatomy of various canal systems and file design in order to make the best choice for each individual case. Properly formed access cavity and knowledge of the working part of NiTi files enable maximum realization of endodontic skills, increased efficiency of intervention and reduced possibility of error during canal instrumentation. The special treatment of NiTi alloy and new solutions related to the design of the working part have significantly increased file flexibility and resistance to cyclic fatigue. Specific design (reduced number of threads, change of conicity, interruption of blade continuity), reduced engagement of file, ie. change of dynamics of movement in the canal (full rotation, reciprocal, eccentric, transaxial), as well as reduced number of processing files, have also significantly influenced the reduction of fracture risks. The aim of this paper was to analyze the most common reasons for the fracture of NiTi files and emphasize measures and factors that can increase their safe use and reduce complications during canal instrumentation.

Introduction This review aims to investigate modern methods of applying artificial intelligence to diagnose SARS Cov-2 and predict the development of potential emergencies. Methods The most commonly used electronic databases, such as Scopus and Medline during 2020, were searched. A narrative approach was used to synthesize the extracted data. Results In this review paper, it has been shown that the application of artificial intelligence plays a significant role in virus diagnosis and prognosis in clinical trials. It allows resources to be used much more rationally, such as respirators , in hospitals, during the treatment of SARS Cov-2 and the prediction of possible mortality. The obtained results are from the analysis performed on 120 papers and studies that were electronically taken from papers published on Scopus and Pub Med line. Most commonly used artificial intelligence techniques are convolutional neural networks and machine learning. Conclusions Included studies showed that artificial intelligence can significantly improve the treatment of SARS Cov-2, although many of the proposed methods have not yet been clinically accepted. In addition, more effort is needed to develop standardized reporting protocols or guidelines on applying artificial intelligence into conventional clinical practice. This technology is suitable for fast and accurate diagnosis, prediction and monitoring of current patients and prognosis of disease development in future patients.

Introduction/Objective. Irrigation has an important role in root canal cleaning and its efficiency depends on the type of irrigants, the amount, the technique and the irrigation protocol. The aim of this work was to estimate the efficiency of cleaning of the canal walls by using scanning electron microscope analysis after the instrumentation by rotary NiTi instruments with the use of three different irrigation solutions and two final irrigation protocols. Methods. Sixty extracted human incisors were divided into two groups after the rotary instrumentation with the iRace instruments. In both groups, the same amount (1.5 ml) of three solutions (2% sodium hypochlorite solution, 2% chlorhexidine solution, and 10% citric acid solution) and total final irrigation time (90 seconds) was the same. The final irrigation in the first group was accomplished using the technique of continuous irrigation and in the second group it was done using the intermittent protocol. The roots were cut longitudinally and analyzed by thirds (coronal, middle, and apical) on a scanning electron microscope (JSM 6460LV, JEOL Ltd., Tokyo, Japan) with 1,000× magnification. Results. The most efficient cleaning of the root canal walls in both groups was seen after the use of citric acid with the intermittent protocol of the final irrigation (90.7% clean walls), while the least efficient was the final irrigation by chlorhexidine with continuous irrigation (80.3%). The most efficient cleaning of the canal walls in both groups was observed in the coronal third and the largest amount of the smear layer in the apical third. Conclusion. The most efficient cleaning of the canal was achieved by the use of citric acid and the intermittent protocol of the final irrigation. In all tested solutions, the intermittent protocol of irrigation was more efficient than continuous irrigation.

Introduction/Objective. The objective of this study is to use scanning electron microscopy (SEM) to analyze working surfaces of new manual and rotary endodontic instruments and to check possible existence of manufacture dirt particles or defects on the working surface. Methods. In this study, we used three sets of new manual instruments: K-File, KF (Dentsply Maillefer, Switzerland) and Hedstorm Files, HF (SybronEndo Co, USA) and three sets of mechanical Ni-Ti instruments – type K3 (SybronEndo Co, USA) and BioRaCe (FKG DENTAIRE Swiss Dental Products, Switzerland). The instruments were analyzed using SEM method at 170 × magnification while semi-quantitative energy dispersive x-ray analysis was used to determine chemical composition of dirt particles. Fisher test (p < 0.05) was applied in statistical analysis. Results. Results showed that none of the instruments were defect-free. The most common defect type was the presence of metal strips, which were noticed at the surface of all tested instruments. Debris was present on all manual and only one type of mechanical instruments, K3 (39% in the apical and 33% in the middle third). Fretting was noticed in all manual KF and all mechanical instruments of the K3 group. Pitting was common in all manual instruments, KF (33% in the apical and 39% in the middle third) and HF (11% in the apical and 6% in the middle third). Corrosion of the working surface, metal flash, and disruption of the cutting edge were marked only in the KF group. Conclusion. Manufacture defects were noticed in all instruments and the most common type of irregularity were metal strips. Electropolished surface of BioRaCe instruments showed no debris of organic origin.

Introduction/Objective. The application of nickel–titanium (NiTi) instruments in cleaning and shaping of the root canal system is a standard and a precondition for the success of endodontic treatment. The objective of this study was to use scanning electron microscopy (SEM) analysis in order to examine the efficiency of cleaning the apical third of the root canal system using two different NiTi systems with reciprocating movements. Methods. The study included 20 single-rooted teeth (premolars) divided into two groups. In group 1, the canal preparation was realized with a single file UNICONE with reciprocating movements (MEDIN, Inc., Nove Město na Moravě, Czech Republic), and in group 2, with а RECIPROC BLUE instrument with reciprocating movements (VDW GmbH, Munich, Germany). The same quantities of 2% NaOCl solution and 17% EDTA solution were used as irrigation solutions. The samples prepared for SEM analysis of the smear layer in the apical third were evaluated on a scale of 1–5 and at a magnification of 1,000×. Results. SEM analysis pointed to mostly clean canal walls in the apical segment in both tested groups. Slightly cleaner walls were observed after the application of the UNICONE file (78%) compared to the samples of the second group, where the instrumentation was realized by the RECIPROC BLUE file (76%), but without statistically significant differences. Conclusion. Single-file reciprocating systems do not remove the smear layer completely, but provide efficient cleaning of the apical region of the canal.

Introduction The aim of this study was to analyze working surfaces of new hand endodontic instruments and to check possible existence of dirt or defects on working surface that resulted from manufacturing process using SEM. Material and methods Three sets of new hand instruments: K-File (KF), (18 instruments) (Dentsply Maillefer, Switzerland) and Hedstorm Files (HF), (18 instruments) (SybronEndo Co, USA) were used. Instruments were analyzed by SEM method at 170× magnification while semi-quantitative EDS analysis was used to determine chemical composition of dirt particles. Fisher test (p < 0.05) was applied in statistical analysis. Results Results showed that none of the instruments was defect-free. The most common defects were metal strips and fretting noticed at the surface of all tested instruments. Debris was present on all KF (100% in apical and middle third) and HF (56% in apical and 56% in middle third) instruments. Pitting was noticed in KF (33% in apical and 39% in middle third) and HF (11% in apical and 6% in middle third) instruments. Corrosion of working surface, metal flash and disruption of cutting edge were marked only in KF group. Conclusion Manufacturing defects were noticed in all instruments and the most common type of irregularity were metal strips and fretting.

Introduction Materials used for root canal obturation and root perforation are expected to have, in addition to preventing apical, lateral and coronary leakage, antimicrobial effects on microorganisms that are not accessible to chemomechanical instrumentation and intra-canal medications. The aim of this study was to evaluate the antimicrobial effect of a novel calcium aluminate-based endodontic nanostructured biomaterial (ALBO-MCCA) using agar diffusion test. Material and methods the two materials were tested in the study. The nanostructured calcium aluminate was synthesized by the hydrothermal sol-gel method from individual components of calcium aluminate (CaOxAl2 O3 ), calcite (CaCO3 ) and barium sulfate (BaSO4 ) as radiocontrast agent in the ratio of 2:2:1 according to V. Jokanovic's recipe. The other used material was calcium silicate MTA Angelus (Londrina, Brazil). The antimicrobial effect was assessed using agar diffusion test. Standard strains of Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, cultured on blood Mueller-Hinton agar and Candida albicans cultivated on Sabouraud Dextrose Agar, were used as test microorganisms. Results the best antimicrobial effect after 24 h both materials showed against S. aureus. The mean values of the growth inhibition zone for ALBO MCCA were 5.7 ± 0.25 mm and MTA 6.2 ± 0.4 mm. The ALBO MCCA material showed slightly stronger antibacterial effect against E. coli compared to MTA (p < 0.05), whereas none of the materials showed antibacterial effect against E. faecalis. Conclusion the ALBO MCCA material showed certain antibacterial effect on Escherichia coli, Staphylococcus aureus and Candida albicans that was comparable to antibacterial effect of MTA.

Various magnetron-sputtering methods for surface modification of shape memory alloys (SMA) are described in this paper. These methods belong to the most effective methods, which enable mechanical reinforcing of the SMA, showing numerous advantages over conventional methods of electro-polishing. In addition, surface modified SMA, particularly with equiatomic TiNi coatings, is crucial for further development of various endodontic instruments; wires and brackets used for orthodontic teeth movements. Active coatings with bactericide properties and coatings that can be used as barrier for release of toxic Ni ions from the bulk body of SMA obtained by various magnetron-sputtering methods can be successfully combined. Therefore, the review of these methods is given in this paper, with their main characteristics and drawbacks. Magnetron sputtering deposition involves surface modification of SMA in a single-layer, multilayer, graded layers, and nanocomposite thin coatings for obtaining systems with superior "functional" characteristics. These are hardness, scratch, abrasion, and erosion resistance, improved adhesion to various technologically important substrate materials such as polymers, hydrophobicity or hydrophilicity, long-term chemical, thermal, and environmental stability, gas and vapor impermeability, and others. This paper is critical review of the advances in the development of magnetron sputtering modified SMA products in dentistry, with in advance predictable physicochemical, structural and antimicrobial properties.

Introduction/Objective. The aim of this paper was to verify the biocompatibility of the newly synthesized nanostructured material based on calcium aluminate after implantation into the subcutaneous tissue of rats. Methods. The study included 18 rats aged 10–11 weeks, divided into two experimental groups (n = 9). In all animals, incision took place on the back and two pockets of 15 mm in depth were made, in which sterile polyethylene tubes with test materials [calcium aluminate cement (ALBO-CA), calcium silicate cement with the addition of hydroxyapatite (ALBO-CSHA), and mineral trioxide aggregate (MTA) for the control group) were implanted. Six rats of each group were sacrificed in three observational periods (seven, 15, 30 days). Pathohistological analysis included inflammation, bleeding, fibrous capsule, and tissue integrity around the implanted material. Results. After seven days of treatment, ALBO-CA and ALBO-CSHA showed better tissue response compared to MTA, with a statistically significant difference in inflammation intensity (p = 0.2781). The difference in vascular congestion and thickness of the fibrous capsule after implantation of ALBO-CA material compared to MTA was also statistically significant (p = 0.5567). At the end of the 30-day evaluation period, an identical inflammatory response of connective tissue at the site of implanting ALBO-CA, ALBO-CSHA, and MTA (score of 0.7) was recorded. The formation of thick or moderately thick fibrous capsule was found to be the thickest in ALBO-CA (grade 3.7). There were no statistically significant differences between the parameters analyzed after 30 days. Conclusion. Newly synthesized ALBO-CA showed a satisfactory tissue response and confirmed biocompatibility after implantation in subcutaneous tissue of rats.

Introduction/Objective. This study determined the 12 months clinical and radiographic periapical healing of teeth with apical periodontitis treating with different formulations of calcium hydroxide (CH): paste (CHpaste) and gutta-percha points (CH-GP), and chlorhexidine (CHX): gel (CHX-gel) and gutta-percha points (CHX-GP). Methods. Eighty patients with chronic apical periodontitis were randomly allocated to 4 different treatment groups according to the intracanal medicament used: CH-paste, CH-GP, CHX-gel and CHX-GP group. Seventy eight patients were analyzed clinically and radiographically 12-month postoperatively. The Periapical index (PAI) was used for radiographic evaluation of treatment success. Results. Overall outcome was classified according to radiographic evaluation only, because in all patients clinical success was observed. In all groups significant reduction in PAI scores were observed (p < 0.001). The proportions of healed teeth (PAI ≤ 2) were 73.7%, 60.0%, 68.4% and 65.0% in CH-paste, CH-GP, CHXgel and CHX-GP group, respectively, with no significant differences between the groups. Conclusion. The results suggested that there are no differences between investigated CH- and CHXdelivery systems regarding treatment outcome of teeth with apical periodontitis.

Introduction the main objective of endodontic treatment is to eliminate infection from root canal and prevent re-infection by three-dimensional hermetic obturation of the canal system. Endodontic failure can occur due to inability of complete control and elimination of infection from the root canal. The aim of this study is to investigate, by PCR technique, microbiological status of previously endodontically unsuccessfully treated teeth immediately after the removal of obturation material. Material and Methods the analysis included 30 teeth indicated for endodontic retreatment. After removing previous root canal filling material, the bacteriological sample was taken by sterile instrument (# 15) and paper points. Standard PCR technique was used to analyze the incidence of E.faecalis, P.micros, P.intermedia, P. endodontalis and a.actinomycetemcomitans. Results Positive bacteriological findings were registered in 80% of cases, while bacteria were not identified in 20% of all samples (all taken from the root canals without significant changes in periapical tissue). From 24 canals with identified bacteria, 17 had affected apical periodontium. The most dominant microbe in root canals with positive bacteriological finding was E.faecalis (83.3% of the canals) and P.intermedia (75%). In case of teeth with chronic periapical changes, the most common was E. faecalis (94%) and P.intermedia (82.3%). Conclusion the presence of periapical lesions significantly affects microbiological status of endodontically treated teeth. The presence of bacteria was confirmed in most teeth with periapical lesions, while the most frequently identified bacteria were E. faecalis, P.intermedia and P.micros.

Introduction Efficient cleaning and canal design present a basic precondition for successful endodontic treatment. The aim of this study was to evaluate, using SEM analysis, the efficacy of cleaning the apical third of the canal with one instrument in both reciprocating motion and full rotation systems. Materials and methods Thirty (30) single-rooted teeth (upper incisors), extracted due to periodontal problems, were used and selected in 2 groups. In the group 1, instrumentation was done with a single instrument UNICONE with reciprocal movements (MEDIN, Czech Republic), while in the group 2, a single instrument XPS endo SHAPER (XPS) (FKG, Dentaire, Swiss) with full rotation was used. 2% solution of NaOCl and 17% EDTA solution were used as irrigation agents in both groups. SEM analysis of the smear layer in the apical third was done at standard magnification of 1000x and presented on a scale of 1-5. Results showed mostly clean canal walls and no smear layer in the apical region in both tested groups. Canal walls were somewhat cleaner after using UNICONE with reciprocal movements (80%) compared to the canals instrumented with XPS ENDO SHAPER (76%), but this difference was not statistically significant. Conclusion Single-file NiTi systems did not remove smear layer completely, but provided efficient cleaning in the api-cal part of the canal. UNICONE file with reciprocal movements was somewhat more efficient in removing the smear layer compared to the full rotation XPS ENDO SHAPER file.

Introduction Cytokine network plays an important role in pathogenesis of chronic periapical lesions. The aim of this study was to determine the concentration of interleukin-6 (IL-6) in tissue homogenates of human periapical lesions and correlate its levels with symptomatology and size of the lesions. Materials and Methods 93 samples of chronic periapical lesions were obtained after extraction of teeth. Samples were divided according to the clinical presentation as symptomatic and asymptomatic, and according to the size as large and small. The concentration of IL-6 was analyzed using ELISA. Results Statistically significant difference in IL-6 concentration was observed in symptomatic lesions compared to asymptomatic (p

Introduction The aim of this study was to compare compressive strength (Cs) of new nanostructural calcium silicate based cement (nCS) with commercial calcium silicate cement and conventional GIC. Methods Four nanostructural materials were tested: nanostructural calcium silicate based cement (nCS) (Jokanović et al.), MTA Plus (Cerkamed, Poland), Fuji IX (GC Corporation, Japan) and Ketac Universal Aplicap (3M ESPE, USA). Five samples of each material were mixed in accordance with manifecturer's guidelines and positioned in metal moulds (ϕ4mm and 6mm). Compressive strength (Cs) expressed in MPa was determined after 24 hours, 7 days and 28 days respectively. Measurements were performed on universal testing equipment (Tinius Olsen, USA) at a crosshead speed of 1mm/min. For processing the results one-way ANOVA and post-hoc test were used. Results The highest values of compressive strength after 24h was found in conventional GIC Fuji IX (mean 38.56±13.31) and Ketac Universal (mean 40.77±7.96). Calcium silicate cements after 24h showed low values of compressive strength (MTA Plus 5.91±0.28 MPa, nCS 1.35±0.36 MPa). After 7 days, FUJI IX 47.42±9.33 MPa and Ketac Universal 35.25±10.60 MPa showed higher value of compressive strength than MTA Plus (15.09±2.77 MPa) and nCS (11.06±0.88 MPa). After 28 days the Cs value for conventional GIC Fuji IX was 48.03±7.82 MPa and Ketac Universal 36.65±11.13 MPa while for calcium silicate cements it was 16.47±1.89 MPa and nCS 14.39±1.63 MPa. There was statistically significant difference (p

Introduction/Objective. Development of materials which could be used as biological bone substitutes is one of the most valuable and active fields of biomaterial research. The goal of the study was to research the reaction of tissue on calcium silicate- (CS) and hydroxyapatitebased (CS-HA) newly synthesized nanomaterials, after being implanted into the subcutaneous tissue of a rats and direct pulp capping of rabbit teeth. Methods. The tested materials were implanted in 40 Wistar male rats, sacrificed after seven, 15, 30, and 60 days. The direct pulp capping was performed on the teeth of rabbits. Cavities were prepared on the vestibular surface of the incisors. The animals were sacrificed after 10 and 15 days. The control material was mineral trioxide aggregate (MTA). Histological analysis covered the tracking of inflammatory reaction cellular components, presence of gigantic cells, and necrosis of the tissue. Results. Seven days after the implantation, the strongest inflammatory response was given by the MTA (3.3 Ѓ} 0.48), while CS and CS-HA scored 3 ± 0.71. After 60 days, the rate of inflammatory reactions dropped, which was the least visible with CS-HA (0.2 ± 0.45). The least visible inflammatory reaction of the rabbits’ pulp tissue was spotted with the CS (1.83 ± 0.75), than with the MTA and CS-HA (2.67 ± 1.53, 3 ± 0.63). Conclusion. The newly synthesized materials caused a slight reaction of the subcutaneous tissue. CS-HA showed the best tissue tolerance. Nanostructural biomaterials caused a slight to moderate inflammatory reaction of the rabbits’ pulp tissue only in the immediate vicinity of the implanted material.

There is growing need for synthetic tissue replacement materials designed in a way that mimic complex structure of tissues and organs. Among various methods for fabrication of implants (scaffolds), 3D printing is very powerful technique because it enables creation of scaffolds with complex internal structures and high resolution, based on medical data sets. This method allows fabrication of scaffolds with desired macro- and micro-porosity and fully inter- connected pore network. Rapid development of 3D printing technologies has enabled various applications from the creation of anatomical training models for complex surgical procedures to the printing of tissue engineering constructs. The aim of current investigations was to develop compatible printers and materials (bioinks) to obtain biomimetic scaffolds, which allow printing of living cells without significant loss of cell viability. The advanced level of such printing assumes “in situ” printing, i.e. printing cells and biomaterials directly onto or in a patient that will reduce recovery time.

Introduction Development of inflammatory lesions or their persistence after primary treatment is considered endodontic failure. The reason for failure can be complex anatomy of the canal system and numerous iatrogenic factors. The objective of this study was to analyze, clinically and radiographically, the causes of primary endodontic treatment failure and assess possibilities for retreatment of teeth with failed endodontic treatment. Method The study included 79 teeth (36 multirooted and 43 singlerooted tooth) indicated for repeated endodontic treatment. Based on the radiographic assessment of the status of periapical structures, teeth were divided into two groups. The first group included teeth without periapical lesions, i.e. the healthy periodontal tissues (PAI score of 1 and 2) in which retreatment was required for prosthodontic reason due to the poor quality of obturation (28 teeth), and the second group included teeth with visible signs of periapical tissue damage (PAI scores 3, 4 and 5) (51 teeth). In both groups, quality of obturation, coronal sealing and the presence or absence of clinical symptoms was analyzed. Results The most common radiographic finding of definitive obturation was short filling (65.8% of cases); “forgotten” canals (25.3%); non-homogeneous obturation with correct length (5.1%) and fractured instrument (3.8%). There was significant difference between healthy periodontal ligament and adequate restoration (P < 0.001). In 95% of patients with symptoms, changes in the periapical tissue were observed. Also, there was significant difference in the presence of symptoms after primary treatments, between the teeth with healthy apical periodontal tissue and teeth with periapical lesions (P = 0.019). Conclusion The outcome of the root canal treatment is significantly affected by the quality (density) of obturation and the presence and quality of coronal restoration. In patients with symptoms there were changes in the periapical tissue.

Introduction The aim of this study was to evaluate the efficacy of new rotary NiTi instrument XP endo SHAPER (XPS) used with conventional irrigation protocol on the root canal cleaning in the apical area. Material and methods The research was conducted in vitro on 40 extracted single-rooted teeth divided into the four groups. Instrumentation in the first group was performed using iRa Ce NiTi rotary instruments, in the second group the same instruments were used plus XP endo FINISHER (XPF) for smear layer removal. In the third group, canal instrumentation was done using new instrument XPS, and in the fourth XPS instruments plus XPF was used. During the instrumentation 2% NaOCl solution was used for rinsing canals. The SEM analysis of the cleaning quality in the apical third of the canal was performed on longitudinal root cross-sections and standardized microphotography with a 2000x magnification. Results The thickest smear layer in the apical third was recorded in the first group (iRa Ce) NiTi instruments (2.12), and somewhat less in the group with the new XPS instrument (1.95). An identical and somewhat smaller amount of smear layer was registered in the second and fourth groups where XPF was used with the final irrigant (1.64) (p

Introduction. Biodegradable porous scaffolds are found to be very promising bone substitutes, acting as a temporary physical support to guide new tissue regeneration, until the entire scaffold is totally degraded and replaced by the new tissue. Objective. The aim of this study was to investigate cytotoxicity of a synthesized calcium hydroxyapatite based scaffold, named ALBO-OS, with high porosity and optimal topology. Methods. The ALBO-OS scaffold was synthesized by the method of polymer foam template. The analysis of pore geometry and scaffold walls’ topography was made by scanning electron microscope (SEM). The biological investigations assumed the examinations of ALBO-OS cytotoxicity to mouse L929 fibroblasts, using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidefor (MTT) and lactate dehydrogenase (LDH) tests and inverse phase microscopy. Results. The SEM analysis showed high porosity with fair pore distribution and interesting morphology from the biological standpoint. The biological investigations showed that the material is not cytotoxic to L929 cells. Comparison of ALBO-OS with Bio-Oss, as the global gold standard as a bone substitute, showed similar results in MTT test, while LDH test showed significantly higher rate of cell multiplication with ALBO-OS. Conclusion. The scaffold design from the aspect of pore size, distribution, and topology seems to be very convenient for cell adhesion and occupation, which makes it a promising material as a bone substitute. The results of biological assays proved that ALBO-OS is not cytotoxic for L929 fibroblasts. In comparison with Bio-Oss, similar or even better results were obtained. [Projekat Ministarstva nauke Republike Srbije, br. 172026]

Introduction. Endodontic retreatment is a complex intervention that requires detailed analysis of possible reasons for failure, and flawless practical execution of the procedure. Objective. The aim of the study was to assess the outcome of endodontic retreatment based on clinical and radiographic criteria after a two-year observation period. Methods. Clinical study included 49 teeth indicated for endodontic retreatment based on periapical index (PAI). All teeth were divided into two groups. Group I comprised teeth without any periapical lesion (PAI score of 1 and 2) while Group II consisted of teeth with visible periapical radiolucency (PAI score of 3, 4, and 5). Endodontic retreatment was completed in two visits with inter-appointment medication of 2% chlorhexidine and calcium hydroxide for two weeks. Outcome of endodontic retreatment was evaluated 12-24 months after final obturation. Results. Endodontic retreatment was successful in 93.3% in Group I after 24 months. In Group II, successful treatment and complete healing was found in 52.9% of teeth, whereas 14.7% of teeth showed only partial healing. However, clinical symptomatology was not present in any of the cases. Considering the absence of clinical signs and subjective symptoms, retreatment was successful in 67.6% of cases where chronic periapical inflammation was present. Conclusion. Endodontic retreatment was successful in high percentage in teeth with and without periapical lesions.

Introduction During endodontic treatment smaller or larger areas of root canal wall remain non-instrumented. This can affect prognosis of endodontic treatment as some bacteria may be left behind. The purpose of this study was to evaluate the morphology of non-instrumented areas of the root canal wall using scanning-electron-microscopy (SEM) after completed instrumentation and various irrigation regiments. Materials and Methods Eighteen single-rooted extracted teeth were divided into the six groups. One tooth in each group represented a control sample. In all samples only one half of the canal was instrumented using ISO 40 hand files. Control samples were subjected to an irrigation protocols without instrumentation. Irrigants used were physiological saline, 3% sodium hypochlorite and 15% of ethylene-diamine-tetra-acetate. Irrigation protocol included using each of these irrigants alone, or a combination of NaOCl and EDTA, as well as their combination with final irrigation using NaOCl or chlorhexidine. Then after, roots were sectioned longitudinally and prepared for SEM. Results Saline irrigation left pulpal debris on uninstrumented areas of the canal wall. Irrigation with 3% NaOCl left behind canal wall with different forms of calcospherites. However, after EDTA irrigation dentin appeared as an undulating surface with open tubules without a smear layer. The combination of NaOCl and EDTA showed remnants of calcospherites and open slightly widened dentinal tubules. Final irrigation with NaOCl on the uninstrumented areas showed enlarged dentinal tubules along with dentinal erosion, while after final irrigation with CHX clean dentin and open dentinal tubules without smear layer were noted. Conclusion From the morphological point of view, the most favorable effect of irrigation on both uninstrumented and uninstrumented canal walls was achieved after irrigation with NaOCl and EDTA or NaOCl, EDTA and chlorhexidine as the final irrigant.

This paper analyzes mechanisms of fluorapatite mechanochemical synthesis and its structural characteristics. Several studies of Jokanovic et al. published in appropriate journals and the book 'Nanomedicine, the biggest challenge of the 21st century' are the base for this article. Characteristics of obtained materials show numerous biological advantages associated with the specific structural design of material during the process of synthesis. X-ray diffraction (XRD) and infrared spectroscopy with Fourier transform (FTIR) were used for studying the processes of fluorapatite synthesis.

The application of irrigating solutions is essential in chemomechanical treatment of tooth root canal. However, chemical and electrochemical aggressiveness of the solutions, which directly act on instruments, may damage their surface. The aim of this study was to investigate the sensitivity of the nickel-titanium (Ni-Ti) and stainless steel endodontic files to corrosive action of the sodium hypochlorite (NaOCl), chlorhexidine gluconate (CHX) and ethylenediamine tetraacetic acid (EDTA). Testing of sensitivity to corrosion of the instruments was performed by dynamic potentiometric method. Measurements were made in 5.25% NaOCl, 0.2% CHX and 17% EDTA. Ni-Ti instruments immersed in 5.25% NaOCl showed the most intensive corrosive changes and the lowest value of pitting potential of 1.1V. Stainless steel instruments immersed in 5.25% NaOCl showed higher value of pitting potential of 1.5V. Stainless steel instruments immersed in 0.2% CHX showed lower corrosive surface changes and higher value of pitting potential of 1.6V, whereas Ni-Ti instruments immersed in 0.2% CHX showed the pitting potential of 1.9V. The corrosion was not observed in both types of instruments after immersion in 17% EDTA. The use of 5.25% NaOCl and 0.2% CHX may cause severe surface corrosion of Ni-Ti and stainless steel endodontic files. [Projekat Ministarstva nauke Republike Srbije, br. 175102]

Introduction Direct pulp capping is an important therapeutic method that has goal to provide formation of dentin bridge and healing process of the pulp. The aim of this study was to investigate the effects of new nanostructural materials based on calcium silicate systems and hydroxyapatite on exposed dental pulp in Vietnamese pigs. Material and Methods The study was conducted on 30 teeth of two Vietnamese pigs (Sus scrofa verus). On buccal surfaces of incisors, canines and first premolars, class V cavities were prepared with a small round bur and pulp horn was exposed. In the first experimental group (10 teeth) the perforation was covered with new nanostructural material based on calcium silicate systems (CS). In the second experimental group, the perforation was covered with compound of calcium silicate systems and hydroxyapatite (HA-CS) (10 teeth). In the control group, exposed pulp was covered with Pro Root MTA® (Dentsply Tulsa Dental, Johnson City, TN, USA) (10 teeth). All cavities were restored with glass ionomer cement (GC Fuji VIII, GC Corporation, Tokyo, Japan). Observation period was 28 days. After sacrificing the animals, histological preparations were done to analyze the presence of dentin bridge, inflammatory reaction of the pulp, pulp tissue reorganization and the presence of bacteria. Results Dentin bridge was observed in all teeth (experimental and control groups). Inflammation of the pulp was mild to moderate in all groups. Neoangiogenesis and many odontoblast like cells responsible for dentin bridge formation were detected. Necrosis was not observed in any case, neither the presence of Gram-positive bacteria in the pulp. Conclusion Histological analysis indicated favorable therapeutic effects of new nanostructural materials based on calcium silicate systems and hydroxyapatite for direct pulp capping in teeth of Vietnamese pigs.

Introduction. The study included application of liners and dental composites in to cavities of six experimental animals - rabbits (Oryctolagus cuniculus). Objective. The aim of the study was to investigate rabbit dental pulp response to different liners. Methods. Cavity preparation for class V were made on the maxillary central incisors and one lower incisor, while the second lower incisor served as a control tooth. These teeth were restored with the use of one of the following liners - Calcimol LC, ANA Liner and Fuji II LC Improved, and Ceram-X mono dental composite. After an observation period of five days animals were sacrificed and prepared for histological analysis. The existence and degree of the pulp inflammation was determined by using a light microscope. Results. Results showed that the used liners do not cause distortion of the structure and continuity of the odontoblastic layer. Inflammation was not registered in the control group, while in each group of tested materials one tooth with mild signs of hyperemia was registered. Results showed that all three tested liners demonstrated favorable effects on the pulp of the tooth and did not lead to inflammatory reactions. Conclusion. Histological analysis of the dental pulp of experimental animals suggests that the liners used in this study do not compromise the integrity of the odontoblastic layer, if it is applied over a thin layer of dentin. In each group of tested materials one tooth with mild signs of hyperemia and vasodilation was registered.

Introduction. Direct pulp capping procedure is a therapeutic application of a drug on exposed tooth pulp in order to ensure the closure of the pulp chamber and to allow the healing process to take place. Objective. The aim of this study was to examine the histological effects of Emdogain® on exposed tooth pulp of a Vietnamese pig (Sus scrofa verus). Methods. The study comprised 20 teeth of a Vietnamese pig. After class V preparation on the buccal surfaces of incisors, canines and first premolars, pulp was exposed. In the experimental group, the perforations were capped with Emdogain® (Straumann, Basel, Switzerland), while in the control group pulp capping was performed with MTA® (Dentsply Tulsa Dental, Johnson City, TN, USA). All cavities were restored with glass-ionomer cement (GC Fuji VIII, GC Corporation, Tokyo, Japan). The observational period was 28 days, after which the animal was sacrificed and histological preparations were made. A light microscope was used to analyze dentin bridge formation, tissue reorganization and inflammation, and the presence of bacteria in the pulp. Results. The formation of dentin bridge was observed in the experimental and control groups. Inflammation of the pulp was mild to moderate in both groups. Angiogenesis and many odontoblast-like cells, responsible for dentin bridge formation, were observed. Necrosis was not observed in any case, nor were bacteria present in the pulp. Conclusion. Histological analysis indicated a favorable therapeutic effect of Emdogain® Gel in direct pulp capping of Vietnamese pigs. Pulp reaction was similar to that of MTA®. [Projekat Ministarstva nauke Republike Srbije, br. ON172026]

Introduction Calcium silicate cements can be successfully used for the treatment of root perforations due to their exceptional biological and sealing properties. The aim of this study was to test, using dye penetration method, marginal microleakage of newly synthesized nanostructured biomaterials based on calcium silicate system and hydroxyapatite after their application in interradicular perforation of extracted teeth. Material and Methods The study included 34 extracted human molars. Newly synthesized nanostructured materials: one based on calcium silicate system (CS), and the other one based on hydroxyapatite and active calcium silicate system (HA-CS) were tested. Mineral trioxide agreaggate (MTA; Angelus, Londrina, Brazil) was used as control. Marginal microleakage was evaluated using dye penetration test 6 months after the application of materials in experimentally prepared inter-radicular perforations in extracted human molars. Dye penetration was analyzed using light microscope at 30X magnification, a method of quantifying visual information in computer software for image processing (Adobe Photoshop CS5 Extended, version 12.0 x 32). The values were expressed in millimeters, and the results statistically analyzed using one-way ANOVA and Tukey post-hoc test (α=0.05). Results The shortest dye penetration was measured for calcium silicate system (0.44 mm), while slightly higher values were found for MTA (0.54 mm). Dye penetration for hydroxyapatite and active calcium silicate system (2.00 mm) was longer than for the other two materials (p

Introduction The aim of this study was to evaluate using SEM analysis the effectiveness of a new instrument XP-endo Finisher in cleaning root canal walls after instrumentation with BioRaCe NiTi rotary instruments. Material and Methods This in vitro study was conducted on 30 extracted single rooted teeth divided in two groups. Instrumentation of all canals was done using basic BioRaCe NiTi rotary instruments with copious irrigation of 2% NaOCl. In the first group, after complete instrumentation smear layer was removed using XP-endo Finisher, while the other group served as negative control. The roots were then after longitudinally cut and SEM analysis was performed. The presence of smear layer in the coronal, middle and apical third was assessed. The data were statistically analyzed using Mann-Whitney U-test (p

Introduction Separation (fracture) of endodontic instruments in the root canal during chemomechanical instrumentation is a complication that can compromise the final outcome of endodontic treatment. One of the most common factors that cause fatigue of endodontic instruments and consequent fracture is surface corrosion. The aim of this study was to investigate the ultrastructure of surface corrosion of endodontic instruments made of stainless steel and nickel-titanium after immersion in the most commonly used root canal irrigants. Material and Methods The study included 48 nickel-titanium and stainless steel endodontic hand files. All instruments were immersed in 5.25% sodium hypochlorite, 0.2% CHX and 17% EDTA. Surface corrosion was analyzed using a scanning electron microscope (SEM). Results Nickel-titanium instruments showed significantly higher susceptibility to corrosion after immersion in 5.25% sodium hypochlorite compared to stainless steel instruments (p

Bioactive glasses are often used nanomaterials in tissue engineering of bone and soft tissue. Many newly synthesized materials for applications in medicine and dentistry are based on these bioactive substances. Bioactive glass is usually used as a scaffold or as an implant coating on implants and it allows fast formation of apatite layer with positive effect on osteoblasts proliferation. These biomaterials play an important role in dentistry and endodontics. This study is mostly part of the monograph titled 'Nanomedicine, the Greatest Challenge of the 21st Century', that for two years has received attention from professional and scientific community in various fields. Information presented in this paper highlight structural characteristics of bioactive glasses that have a significant role in bone tissue engineering.

Introduction. Because apical periodontitis is recognizably an infectious disease, elimination or reduction of intracanal bacteria is of utmost importance for optimum treatment outcome. Objective. The prevalence of Enterococcus faecalis and Porphyromonas gingivalis in infected root canals was studied Also, the effect of endodontic therapy by using intracanal medicaments, calcium hydroxide paste (CH) or gutta-percha points containing calcium hydroxide (CH-GP) or chlorhexidine (CHX-GP) on these microorganisms was assessed by polymerase chain reaction (PCR) assay. Methods. Fifty-one patients with chronic apical periodontitis were randomly allocated in one of the following groups according to the intracanal medicament used: CH, CH-GP and CHX-GP group. Bacterial samples were taken upon access (S1), after chemomechanical instrumentation (S2) and after 15-day medication (S3). PCR assay was used to detect the presence of selected bacteria. Results. E. faecalis was detected in 49% (25/51) and P. gingivalis in 17.6% (9/51) of the samples. Samples which showed no bacterial presence at S1 were excluded from further analysis. Overall analysis of all 29 samples revealed significant differences between S1 and S2 (p

Introduction. Bonding between composite and hard dental tissue is most commonly assessed by measuring bonding strength or absence of marginal gap along the restoration interface. Marginal index (MI) is a significant indicator of the efficiency of the bond between material and dental tissue because it also shows the values of width and length of marginal gap. Objective. The aim of this investigation was to estimate quantitative and qualitative features of the bond between composite resin and enamel and to determine the values of MI in enamel after application of two techniques of photopolymerization with two composite systems. Methods. Forty Class V cavities on extracted teeth were prepared and restored for scanning electron microscope (SEM) analysis of composite bonding to enamel. Adhesion to enamel was achieved by Adper Single Bond 2 - ASB (3M ESPE), or by Adper Easy One - AEO (3M ESPE). Photopolymerization of Filtek Ultimate - FU (3M ESPE) was performed using constant halogen light (HIP) or soft start program (SOF). Results. Quantitative and qualitative analysis, showed better mikromorphological bonding with SOF photopolymerization and ASB/FU composite system. Differences in MI between different photopolymerization techniques (HIP: 0.6707; SOF: 0.2395) were statistically significant (p