Despite advances in the 21st century, dental caries still remains to be one of the most common infectious diseases. Its prevalence was confirmed by the World Health Organization and affirms dental caries as a major health problem in all over the world. Even though the process of tooth decay is multifactorial, the oral bacteria, mutans streptococci, such as Streptococcus mutans and Streptococcus sobrinus, are considered to be causative agents of dental caries in human. Numerous studies carried out on animals and various categories of vaccines were developed such as whole cell vaccine, subunit vaccine, and synthetic peptides. Irrespective of success from active and passive immunization based on animal trials, it is the phenomenon of human heart reactivity that limited the applicability of these trials in humans. Continuous efforts are being made to overcome these limitations and for further success in human trials. With the advent of various antibodies against antigens of mutans streptococci, local passive immunization has become the safer approach in humans against the colonization of bacteria and caries induction. This review provided insight into epidemiology, active and passive immunization in both animal and human trials, as well as the prospects of caries vaccination.a

Aim: This study aimed to compare the compressive strength, shear bond strength, and microhardness of glass-ionomer cement (GIC) Type IX and Cention N. Materials and Methods: Five samples each of GIC Type IX and Cention N were prepared for testing the shear bond strength, tensile strength, and microhardness. Cylinders of the samples measuring 1 cm diameter and 6 mm height were prepared for compressive strength and shear bond strength. For shear bond strength, these samples were embedded into acrylic blocks of dimensions 2 cm × 2 cm. Testing of shear bond strength and compressive strength was done by mounting the samples in a universal testing machine with a crosshead speed of 1 mm/min. The samples for microhardness were 1 cm diameter and 5 mm height. The samples were mounted on Vickers microhardness testing machine to test the microhardness. Results: The values for shear bond strength of Cention N were statistically highly significant (P < 0.01) as compared to GIC Type IX, whereas the compressive strength and microhardness values of Cention N were statistically significant (P < 0.5) as compared to GIC Type IX. Conclusion: The results suggest significantly higher values for mechanical properties of Cention N as compared to GIC Type IX.

Context: It is essential to know if the immersion in sodium hypochlorite (NaOCl) influences the cyclic fatigue resistance of nickel-titaniumm (NiTi) files. Aim: This study was aimed to evaluate the resistance to the cyclic fatigue of three NiTi systems, as well as the influence of 5.25% NaOCl on their resistance. Methods: Files from the Sequence Rotary File (MK life, Porto Alegre, Brazil), ProTaper Next (PTN) (Dentsply, Maillefer, Baillagues, Switzerland), and HyFlex EDM (Coltène Whaledent, Allstatten, Switzerland) systems were tested and separated into Group 1)-without immersion in NaOCl solution and Group 2 and Group 3-immersed in 5.25% NaOCl solution, for 1 min, and 5 min, respectively. All instruments were submitted to the cyclic fatigue test. Images of the instruments were observed by scanning electron microscopy, to evaluate the type of defect presented on the fractured surface. The test performed for the analysis of two independent factors was a two-way analysis of variance. Results: HyFlex EDM presented a greater number of cycles until fracture when compared to others (P < 0.001). The control group showed a greater number of cycles until fracture than the same instruments submitted to NaOCl (P < 0.001). Sequence instruments showed the lowest values of cycles until fracture (P < 0.001). There was no statistically significant difference between treatments (P = 0.998). PTN, showed intermediate values of fracture resistance when compared to the HyFlex EDM and sequence instruments (P < 0.001), but without intragroup differences (P = 0.437). Conclusions: Hyflex EDM instruments were the most resistant to cyclic fatigue.

Aim: This study aimed to evaluate the effect of a laser-activated bleaching agent containing titanium dioxide (TiO₂) nanoparticles on enamel roughness and hardness. Materials and Methods: Twenty human premolars were randomized into two groups according to the bleaching treatments performed: HP – 35% hydrogen peroxide and HP + TiO₂ – 30% hydrogen peroxide containing TiO₂ light-activated by diode laser (980 nm). It was performed two bleaching sessions with an interval of 7 days. Microhardness and roughness of the enamel were assessed at three times: T0 – Before 1^st appointment, T1 – after 2^nd appointment, and T2–7 days after 2^nd appointment. Results: The HP + TiO₂ did not cause changes on enamel roughness and hardness and presented the same effects of the HP. Conclusions: Both bleaching agents showed no difference between them. Then, it is possible to conclude that both are viable for clinical use during in-office dental bleaching technique regarding the microstructural changes that they might cause.

Objective: The aim of the study was to evaluate the prevalence of root canal isthmus (RCI) and measure the interorifice distance (IOD) between the root canals. Additionally to correlate IOD with the RCI in human permanent teeth using cone-beam computed tomography (CBCT) in an Indian sub-population (Chennai). Materials and Methods: A total of 5881 teeth from 280 CBCT full mouth scans were analyzed. The presence or absence of complete and incomplete RCI of each tooth was identified using the map-reading strategy. IOD was calculated by measuring the distance between the center of each root canal orifice to that of the center of the adjacent orifice at the level of the cementoenamel junction using the axial and sagittal sections. Chi-square analysis and correlation statistics using Spearman's rank-order test was done (P < 0.05). Results: High prevalence of RCI was found in maxillary first premolars, mesial root of mandibular molars, and mesiobuccal root of maxillary first molars, while its prevalence was low in maxillary canines and mandibular premolars and absent in maxillary incisors. RCI was predominantly seen in the cervical and middle third of the root canal in all the teeth evaluated. A weak negative correlation was established between the IOD and RCI for maxillary premolars, whereas a weak positive correlation was seen in maxillary first molars and mandibular second molars. Conclusion: The prevalence of RCI was high in the posterior teeth in comparison to the anterior teeth in the present study. There was no strong correlation between IOD and RCI in all the teeth evaluated.

Aim of the Study: The purpose of this study is to compare and analyze the antimicrobial activity of three different root canal sealers. Materials and Methods: In this study, the antimicrobial activity of three different root canal sealers were compared against two strains of bacteria Enterococcus faecalis which is known to be common isolates of necrotic pulp and endodontic lesions. This test was done at various time intervals (1, 6, 15, and 60 min) using agar diffusion test and direct contact test. Results: Bioceramic showed the best antimicrobial activity against E. faecalis among the three groups of sealers used. Moreover, the results were statistically analyzed. Conclusion: Within the limitations of this study, it can be concluded that Bioceramic sealer showed the best antimicrobial activity followed by MTA Fillapex and Apexit.

Aim: The present study aimed to individually evaluate and compare the aerobic and anaerob?ic antibacterial activity of Allium sativum extract, aqueous ozone, diode laser, and 3% sodium hypochlorite (NaOCl) as root canal irrigants. Materials and Methods: Forty-eight patients were selected and randomly allocated to one of the four groups (n = 12 each) according to the irrigant to be used in each group. For each included tooth, the preirrigation and postirrigation (after irrigation with the test solution) samples were collected through sterile paper points and microbial culturing was done by swabbing on blood agar plates followed by incubation for aerobic and anaerobic bacteria. Statistical Analysis: Manual colony-forming units counting were done, and statistical analysis was performed. Analysis of variance (one-way) followed by post hoc test was performed as a parametric test to compare the difference between the groups for both aerobic and anaerobic bacteria. Results: All the groups showed a statistically significant reduction in bacteria (P < 0.05). However, between the groups, the maximum reduction was seen with 3% NaOCl followed by diode laser, A. sativum extract, and least by aqueous ozone. Conclusion: A. sativum extract, aqueous zone, diode laser, and 3% NaOCl showed significant antibacterial activity against aerobic and anaerobic bacteria.

Context: Dental hypersensitivity and loss of dental tissues are commonly observed in patients, and most of the problems are caused due to total or partial exposure of dentinal tubules. Aims: The purpose of this study is to evaluate the performance of 45S5 bioactive glass and niobophosphate (NbG) associated with neodymium: yttrium-aluminum-garnet (Nd:YAG) laser for the reduction of dentin permeability. Materials and Methods: Fifty bovine dentin discs were made and distributed randomly into five groups (n = 10). The Nd:YAG laser was applied with the bioactive glasses using the energy parameters (60 and 80 mJ), forming the groups; NbG_60: NbG + Nd:YAG (60 mJ); NbG_80: NbG + Nd:YAG (80 mJ), 45S5_60: 45S5 + Nd:YAG (60 mJ); 45S5_80: 45S5 + Nd:YAG (80 mJ) and C: control (untreated dentin). The permeability was measured with a split chamber device. The samples were subjected to the erosive challenge and a new permeability measurement was done. Furthermore, the dentin was analyzed by scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Statistical Analysis Used: The data were analyzed using Kruskal–Wallis and Dunn's tests (α = 0.05). Results: Greater reduction in dentinal permeability was observed for 45S5 bioactive glasses (45S5_60 and 45S5_80) followed by NbG_80 and NbG_60 (P < 0.05). The SEM/EDS analysis showed the formation of a barrier after the dentin treatment. Conclusions: Bioactive glasses with Nd:YAG laser on the dentin surface may be a promising alternative for the reduction of dentin permeability.

Aim of the Study: We aimed to compare stress distribution in a tooth restored with fiber post and dentin post after applying the orthotropic properties using three-dimensional finite element analysis (3D-FEA). Materials and Methods: Two 3D-FEA models were constructed. The material properties were assigned, and a load of 100 N was applied at 45° to the long axis of the model onto the lingual surface incisal to the cingulum. The FEA was done by applying orthotropic properties of dentin and fiber post. The maximum stresses produced in the tooth and post referred to as von Mises stress were recorded. The Ansys software was used which depicts the stress concentrations. Results: Von Mises values showed that glass fiber post (331 MPa) and dentin post (338 MPa)-restored tooth models presented similar stress values. Conclusion: Although both fiber post and dentin post presented similar von Mises stress values, the pattern of stress distribution is more favorable in dentin post. More favorable fracture could be expected in case of dentin post. Thus, the dentin post is a promising alternative post material for rehabilitating endodontically treated teeth. Clinical Significance: Ascribing the orthotropic properties in a FEA study means that the computational simulation was similar to that of clinical scenario, and hence simulates the dynamic intraoral conditions, thereby giving the accurate results.

Aims: This study aims to evaluate the bond strength (BS) and microleakage (ML) of the newer bonding agents to enamel and dentin. Objective: (1) To analyze the BS between self-etch and total-etch adhesives. (2) To analyze the depth of ML between self-etch and total-etch adhesives. Materials and Methods: Sixty mandibular premolars were fabricated and randomly divided into three groups: Group I (n = 20)-bonded with self-etch adhesive + nanohybrid, Group II (n = 20) with total-etch adhesive + micro hybrid and Group III (n = 20) with total-etch adhesive + nanocomposite. Teflon ring molds were used to make composite resin cylinders bonded to the buccal surface. Class II box cavity was prepared on the samples' proximal surface and condensed with composite resin with each group's specific bonding protocol. Shear BS and ML testing were conducted, and data analyzed. Statistical Analysis: Kruskal–Wallis analysis was done to statistically differentiate the BS and ML between the three experimental groups; the P < 0.05, it showed a statistically significant difference. Intergroup comparison was made using the Mann–Whitney U test. Conclusions: Within this study's limitation, resin bonded with self-etch G-Premio Bond used in selective etch technique showed the highest BS and resistance to ML.

Context: This study focuses on the marginal adaptation of a calcium silicate-based cement to the root dentin after retrieval of different intracanal medicaments. Aim: This study compared the marginal adaptation of a calcium silicate-based cement to radicular dentin in the apical third of the root canal following the use of three different intracanal medicaments. Materials and Methods: Forty single-rooted premolar teeth (n = 40) were decoronated 13 mm above the root apices; then, 3 mm of the root tips were resected to standardize the root length. Orthograde cleaning and shaping were done using the rotary files and apical enlargement using peeso reamers. Depending on the intracanal medicament used, the samples were equally divided into four groups: Group 1 - control, Group 2 - Metapex, Group 3 - triple antibiotic paste (TAP), and Group 4 - calcium hydroxide with Propolis. Subsequently, the medicament was removed and a 3 mm apical barrier of Biodentine^TM was placed and later scanned using an ex vivo micro-computed tomography scanner. Statistical Analysis Used: One-way ANOVA F-test and Tukey's post hoc test were used. Results: Maximum adaptation was seen in control group (0.65) > Propolis (1.47) > TAP (4.37) > Metapex (5.25); a high statistically significant difference between the four groups was found (P < 0.001) with regard to the external voids between Biodentine^TM and radicular dentin. Conclusion: On comparison of the marginal adaptation of Biodentine to root canal dentin following the use of three different intracanal medicaments, maximum adaptation was seen in Group 1, followed by Group 4, Group 3, and Group 2.

Background: The principles of minimally invasive dentistry clearly tells us the need for clinically effective measures to remineralize the early enamel caries lesions. Aims and Objectives: The aim of this study was to evaluate the remineralisation potential of four different remineralisation agents used quantitatively by surface microhardness and qualitatively by energy dispersive X ray analysis. Materials and Methods: Artificial enamel lesions were created on the buccal surfaces of 60 extracted mandibular second premolar. Specimens were randomly assigned to four groups (n=15) according to the remineralisation agents used: Group 1-Nano Hydroxyapatite, Group 2-Fluoride, Group 3-CPP ACP, Group 4-Chitosan 5mg. All products were applied according to the manufacturer's instructions and specimens were stored in daily renewed artificial saliva. Surface microhardness was assessed using Rockwell hardness test and change in mineral content was evaluated using Energy Dispersive X ray analysis. Statistical Analysis: One way analysis of Variance test and post-hoc Tukey test were conducted for multiple group comparison. Results: There was remarkable remineralisation in Hydroxyapatite treated comparatively to the other three groups. Conclusion: All remineralising agents showed improved surface remineralisation. However complete remineralisation did not occur within 7 days. Nanohydroxyapatite showed the highest potential for remineralisation followed by CPP-ACP, Chitosan and Fluoride.

Aim: The purpose of this study is to evaluate and compare the effect of different access cavity designs on root canal instrumentation efficacy using micro-computed tomography (CT) scan and resistance to fracture evaluated using the universal testing machine on maxillary central incisor. Materials and Methodology: Forty extracted human permanent maxillary central incisors were divided into four groups for each access cavity. The access cavities were prepared according to predefined criteria and were further assessed under Micro-CT to evaluate pre and postoperative instrumentation efficacy. After biomechanical preparation and obturation, the teeth were wrapped with tin foil to maintain a thickness of 0.2–0.3 mm as periodontal ligament. Then, the silicon impression material was applied in the acrylic alveolus, to maintain and simulate the thickness of periodontal ligament and fracture resistance was checked using the universal testing machine. Statistical Analysis: Data were analyzed using one-way analysis of variance test. Pair-wise comparison was made using post hoc multiple comparison (Tukey) test. Results: Fracture resistance was highest (1272 N) for the control group followed by the Lingual Conventional Access Group (1153.90 N). Fracture resistance for Lingual Cingulum Access Group was 1130.70 N and least for the Lingual Incisal Straight-Line Access Group (1022.80 N). This difference in fracture resistance among all the groups was significant (P = 0.001). Overall comparison showed that dentin volume reduction (DVR) for Group II was 22.45 mm³, for Group III was 17.37 mm³ and for Group IV was 28. 41 mm³. This difference in DVR among the three groups was significant (P = 0.001). Conclusion: The most effective instrumentation efficacy was obtained in lingual incisal straight-line access group, followed by lingual cingulum access group, followed by lingual conventional access group. The most effective fracture resistance was obtained in the lingual conventional access group, followed by the lingual cingulum access group, followed by the lingual incisal straight-line access group.

Context: The polymerization quality of composite resin can be measured by measuring the cure depth. Vickers hardness ratio is an indirect method of measuring the depth of cure of the composite resin. Aims: This study aimed to compare the effect of composite resin type and material thickness on the depth of cure of sonically activated bulk-fill composite resin (SonicFill, Kerr), low viscosity (Surefill SDR bulk-fill, Dentsply), and high viscosity (Tetric N Ceram bulk fill, Ivoclar Vivadent). Settings and Design: The research is experimental laboratory. Materials and Methods: The research samples were 36 cylindrical composite resin blocks with a thickness of 2 mm and 4 mm, which were divided into six groups (n = 6) based on sonically activated bulk-fill composite resin, low viscosity, and high viscosity. All samples were put in an incubator for 24 h. The microhardness ratio was performed using a Vickers microhardness tester with a weight of 100 g for 15 s, which calculated by the formula: Vickers hardness number bottom/top. Statistical Analysis Used: The two-way ANOVA with Tukey post hoc test was used for statistical analysis (P < 0.05). Results: The results of the two-way ANOVA test showed an effect of the type of composite resin on the depth of cure of the composite resin (P < 0.05); there was no effect of material thickness on the depth of cure of composite resin (P > 0.05). There was no interaction of composite resin type and material thickness to a resin composite depth (P > 0.05). Conclusions: The depth of cure of sonic-activated and high-viscosity bulk-fill composite resin was greater than low-viscosity bulk-fill composite resin.

Introduction: Dental caries is a multifactorial disease with the main causative organism being Streptococcus mutans and Lactobacillus spp. “Probiotics” are defined as living microorganisms, principally bacteria, which are safe for human consumption and when ingested in sufficient quantities, have beneficial effects on human health, beyond basic nutrition. These can be used to replace the pathogenic strains of bacteria with the nonpathogenic type in the oral cavity thus can help prevent dental caries. Aims: To evaluate and compare the role of probiotic milk and lozenges on S. mutans and Lactobacillus spp. count on patients who are exposed to probiotics continuously for 7 days. Materials and Methods: Sixty volunteers who were prone to caries were divided into three equal groups. Experimental groups were given probiotics daily for 7 days. In Group A, patients were given milk without any probiotics (control); in Group B, probiotic milk is given; and in Group C, probiotic lozenges are given. Saliva samples were assessed on the 1^st day and after 7 days of intervention. The collected saliva samples were inoculated on the selected culture media and estimation was done by measuring the colony-forming unit. Statistical Analysis Used: Statistical analysis was performed using Student's paired t-test and multiple comparisons by Tukey's honest significant difference test. Results: There was a significant reduction in salivary S. mutans level in both experimental groups after 7 days (P < 0.05). However, there was no significant difference in Lactobacillus count before and after the intervention. Conclusions: Probiotics have a role in reducing salivary S. mutans count. Probiotics lozenges showed greater efficacy in reducing salivary S. mutans count than probiotic milk.

Purpose: The aim of this in vitro study was to investigate the effectiveness of a novel charcoal-containing whitening toothpaste and a mouthwash on tooth color change and the alterations of enamel that may be induced after toothbrushing, corresponding to a 90-day period. Materials and Methods: Forty human canines were used, stained with coffee, and divided into four groups (n = 10) as follows: Group 1 (control) submitted to toothbrushing with deionized water, Group 2 with a regular toothpaste, Group 3 with a whitening toothpaste (1% charcoal), and Group 4 with the same whitening toothpaste in combination with a mouthwash (1% charcoal and 0.5% H₂O₂). After the treatments, ΔE of the teeth was evaluated using an ultraviolet/Vis spectrophotometer, whereas the changes in surface morphology were observed by means of a confocal microscope. Results: The whitening toothpaste increased significantly ΔE (40.5%) compared to the control group (P < 0.001). In addition, the tested whitening toothpaste also increased ΔE (17.7%) compared to the regular toothpaste (P = 0.023). The whitening toothpaste presented smoother surfaces after toothbrushing, but more heterogeneous with numerous large craters, whereas the whitening mouthwash did not influence surface morphology changes. Conclusions: Charcoal-containing toothpastes may enhance the whitening of the teeth, but they should be used carefully due to changes that may induce on enamel. The patients should consult a dental professional for proper use. A charcoal-containing mouthwash in combination with whitening toothpastes probably cannot offer additional whitening effect.

Aim: The aim of the study was to compare the canal transportation, centering ability, and dentin removal of Profit S3 (PS3), One Curve (OC), and ProTaper Gold (PTG) systems using cone-beam computed tomography (CBCT). Materials and Methods: Thirty extracted human single-rooted premolars were used in the present study. Preinstrumentation scanning of all the teeth in arch form was taken using CBCT. To increase standardization, crowns were removed and only teeth measuring 16 mm were included in the study. The samples were randomly divided into three groups, with ten samples in each group; Group I was instrumented with PS3, Group II was instrumented with OC, and Group III – PTG. Postinstrumentation scans were performed, and the two scans were compared to determine canal transportation, centering ability, and dentin removal at 3, 6, and 9 mm, from the apex. Statistical Analysis: One-way-ANOVA and the independent t-test were done for the pairwise comparison. The significance level was set at P = 0.05; statistical analysis was performed with SPSS statistics version 20.0 (SPSS Inc., Chicago, IL, USA). Results: The mean canal centering ratio and canal apical transportation for PS3, OC and PTG show no statistical difference (P > 0.05)?. The mean value of dentin removal showed a statistically significant difference between the three groups (P < 0.05)?. PS3 and OC rotary file showed less removal of dentin compared to PTG (P < 0.00). Conclusion: It was evident that PS3, OC, and PTG had no statistically significant difference when analyzed based on canal transportation and canal centering ratio. However, there was a significant difference among the three groups comparing the removal of dentin. PS3 and OC rotary file showed less removal of dentin compared to PTG.

Aim: The aim of this preliminary study was to compare outcomes of two regenerative endodontic protocols in necrotic teeth with open apices. Methodology: Forty teeth with open apices in patients with an age range of 15-54 were randomly distributed in two groups: group 1, with whole blood clot in the canal (n=20) and group 2, whole blood with Platelet rich plasma (PRP) in the canal (n=20). Clinical and radiological follow up assessments were undertaken over a period ranging from 6 months to one year. Radiographic Root Area (RRA) was measured using the freeware ImageJ. Statistical analysis was performed using the independent samples t test and the Chi-squared test, the significance level was set at p=0.05. Results: There was no difference in the percentage change in RRA between the PRP group and whole blood-clot + PRP group. Conclusion: Whole blood clot and PRP are comparable on the grounds of percentage change in RRA and there is no statistically significant difference between the two in a follow-up period of up to one year.

Restoring extensively damaged endodontically treated posterior teeth is always a challenge in dentistry. The use of endocrowns has gained popularity in restoring severely damaged endodontically treated teeth (ETT) in recent years. In this clinical report, a structurally compromised mandibular second molar with symptomatic irreversible pulpitis and normal apical tissue was endodontically treated. Surgical crown lengthening was attempted thereafter to increase the crown height. However, marginal periodontal tissue re-growth occurred after surgical crown lengthening. The tooth was subsequently restored with endocrown which was fabricated using computer-aided design and computer-aided manufacturing-based hybrid-ceramic. In conclusion, endocrown can be a viable restorative modality for ETT with compromised clinical crown height.

Conservative endodontics has been introduced about a decade ago. Since then, it has been demonstrated that less canal preparations lead to more dentin preservation resulted in decreased stress on tooth structure, mainly in the coronal third of the root, and potentially a higher resistance to fracture. In addition, smaller and larger canal preparations were comparable with regard to the cleanliness of the root canal. The purpose of this case series was to report on the outcome of root canal treatments following a conservative canal preparation, followed by three-dimensional cleaning technique (intracanal heating and ultrasonic activation of NaOCl).