Search Results (33)

This study evaluated the push-out bond strength (PBS) and failure modes of fiber posts cemented with silane-containing self-adhesive resin cement (SARC) compared with conventional SARC and universal adhesive strategies, considering the effects of root section and aging. Ninety single-rooted human premolars were equally assigned to three cementation protocols: silane-containing SARC (PANAVIA SA Cement Universal), conventional SARC (RelyX Universal), and universal adhesive plus SARC (Scotchbond Universal Plus + RelyX Universal). Each group was divided into two aging subgroups: 24 h water storage and thermal cycling (10,000 cycles between 5 °C and 55 °C, 30 s dwell time; n = 15). After root canal treatment and post space preparation, glass fiber posts were cemented, and each root was sectioned to obtain six slices. PBS was measured using a push-out test, and failure modes were examined under stereomicroscopy. Data were analyzed using three-way ANOVA, post hoc tests, Spearman’s correlation, and logistic regression (α = 0.05). Cement type, root section, and aging significantly influenced PBS (p < 0.001). PBS decreased from coronal to apical sections, and thermal cycling reduced PBS in all groups. The universal adhesive plus SARC achieved the highest PBS, while conventional SARC had the lowest PBS. Cementdentin adhesive failures (FM2) predominated overall, with proportions varying between 43% and 90%, and higher PBS values were associated with fewer FM2 failures. The combination of a universal adhesive with SARC provided superior bonding compared to simplified protocols. Although silane-containing SARC improved bonding relative to conventional SARC, durable adhesion to radicular dentin remains challenging, particularly in apical regions. Full article

Background/Objectives: Among the complications of endodontic treatment, root fractures are the most severe and may require tooth extraction. The objective of this study was to develop virtual models of mandibular molars with different endodontic restorations to assess the stress distribution in tooth structures based on the type of corono-radicular restoration, compared with the model of an intact molar. Methods: Four virtual models of a mandibular molar were created: (1) an intact molar with preserved enamel, dentin, dental pulp and cementum; (2) an endodontically treated molar restored with a composite filling; (3) a molar restored with a fiberglass post and monolithic zirconia crown; (4) a molar restored with a metal cast post and monolithic zirconia crown. External force loads from 0 to 800 N were simulated using Finite Element Method (FEM). Results: The highest displacement, strain and stress values were observed in the molar restored with a composite filling, whereas the lowest values were recorded in the molar restored with a fiberglass post and zirconia crown. Critical stresses were primarily concentrated on the pulp chamber floor. Conclusions: The pulp chamber floor was identified as the most vulnerable area for fracture. This underscores the importance of preserving tooth structure to enhance the strength and durability of molars throughout and beyond endodontic treatment. Full article

This study aims to contribute to the understanding of the dental pulp microbiome through metataxonomic analysis of pulp tissues from clinically healthy impacted third molars in 17 patients. Samples from coronal pulp, outer radicular dentin, and negative controls were included. Each sample was spiked with a known bacterial standard. Sequencing of the 16S rRNA V3–V4 region revealed similarity in bacterial taxonomic profiles. The bacterial DNA was detected in all pulp samples, primarily originating from reagent contaminants. Although some oral taxa appeared more abundant in pulp than in dentin or controls, contaminant species overwhelmingly dominated. Most of the extracted DNA was of human origin, rather than bacterial. Our findings question the concept of a core microbiome in healthy pulp and highlight the critical need for rigorous controls in pulpal microbiome studies. Full article

This study aims to evaluate the stress distribution of polyetheretherketone (PEEK) and high noble alloy materials in a detailed 3D model of a central incisor using finite element analysis (FEA). A comprehensive 3D model incorporated the crown, crown cement, post and core, post cement, central incisor root, periodontal ligament (PDL), and bone. The PEEK and high noble alloy material properties were input into the model, and the FEA was performed using ABAQUS software. The results showed that while the stresses on the bone, root, and crown increased slightly with the PEEK compared to the high noble alloy, the difference was minimal and attributed to the PEEK’s reduced stiffness. This led to a higher load transfer to surrounding regions around the post. The factor of safety decreased from 16 to 10 when using PEEK, but this reduction was still within acceptable limits and reduced stress-shielding effects. In conclusion, while there was no significant difference in stress magnitudes and distributions between the PEEK and high noble alloys, the PEEK exhibited superior stress-shielding properties, which may offer an advantage in preserving the underlying tooth structure in post and core restorations. Full article

Objective: One of the suggested methods for lowering polymerization shrinkage and improving the marginal sealing of restorations is the simultaneous light polymerization of the adhesive system and the first layer of the composite material, i.e., the co-curing method. This study investigates how different adhesive polymerization techniques, adhesive systems, tooth section depths, tooth types, and sample aging affect dentin bond strength. Methodology: This experiment tests three adhesive systems, G-Premio Bond (GC), Clearfil SE Bond 2 (Kuraray), and Adper Single Bond 2 (3M ESPE), using two polymerization techniques, namely, separate composite polymerization and simultaneous curing of the composite (“co-curing”). A total of 480 dentin samples are prepared and assigned to 24 groups (3 adhesives × 2 curing methods × 4 aging times). The shear bond strength is measured after one month, three months, six months, and one year, using an UltraTester. The statistical analyses include an ANOVA and Weibull analysis. Results: The separate polymerization of the adhesive and composite shows a significantly higher bond strength than that achieved through co-curing. Significant differences (p < 0.001) exist among adhesives, with Clearfil SE Bond 2 showing the highest bond strength. The bond strength decreases over time. Occlusal dentin has a higher bond strength than radicular dentin. There is no statistically significant difference in the bond strength between the maxillary and mandibular third molars. After one and three months of aging, the experimental groups with the highest average bond strength do not show the highest level of material reliability. Conclusion: The co-curing technique consistently results in a lower bond strength across all the adhesive systems compared to conventional separate polymerization. Full article

Dental infections can disrupt root development in immature permanent teeth, making traditional endodontic treatment challenging. Apexogenesis, a regenerative approach that promotes natural root development, offers a potential solution. However, issues related to disinfection and material biocompatibility still remain. The objective of this study was to evaluate the synergistic antimicrobial and antibiofilm properties of double and triple antibiotic combinations against common oral pathogens, and to incorporate the most effective combination into a thermosensitive hydrogel, to develop an alternative intracanal medication. Antibiotics were tested alone and in combination in planktonic and biofilm conditions of oral bacteria and Candida albicans. The antibiotic combinations with potential antimicrobial synergy were tested on Enterococcus faecalis biofilms in radicular dentin by confocal microscopy. Metronidazole (ME), ciprofloxacin (CI), and fosfomycin (FO) were incorporated into poly(N-vinylcaprolactam) (PNVCL) hydrogels, and their antibiofilm activity was compared to PNVCL hydrogels containing chlorhexidine (CHX) or calcium hydroxide (CH). The cytotoxicity of the hydrogels was assessed on MDPC-23 odontoblast-like cells using metiltetrazolium assays. A statistical analysis was performed using ANOVA followed by Tukey’s test (p < 0.05). The combination of ME + CI + FO showed superior antibiofilm effects in mono- and dual-species biofilms and on biofilms inside dentinal tubules, comparable to CHX. PNVCL hydrogels with ME + CI + FO significantly reduced E. faecalis biofilms in dentinal tubules, exhibiting a higher efficacy than PNVCL + CH. Cytotoxicity tests revealed minimal effects on cell viability for both PNVCL hydrogels with and without antibiotics. In conclusion, ME + CI + FO showed potent antimicrobial synergy and, when loaded in thermosensitive PNVCL hydrogel, demonstrated significant antibiofilm activity and low cytotoxicity. These findings emphasize the potential of this formulation as an effective and biocompatible endodontic medication, especially for the treatment of immature permanent teeth. Full article

Background: Adhesion within endodontic obturation material and root canal walls improves the efficacy of the endodontic treatment by establishing a barrier that inhibits reinfection and entombs residual bacteria. This study evaluates the push-out bond strength (POBS) of calcium silicate sealers compared to an epoxy-resin-based sealer. Methods: A total of 36 extracted mono-radicular teeth were prepared with Pro Taper Ultimate and irrigated with 5.25% sodium hypochlorite and 17% EDTA. The specimens were randomly split into three groups (n = 12) according to the endodontic sealer and filling technique used as follows: Ah Plus with the continuous wave condensation technique (CWC), Ah Bioceramic (Ah Bio) with the single-cone technique, and Total Fill Hi-Flow (FKG Hi-Flow) with the CWC technique. The material was allowed to set for 4 weeks, and afterwards, the roots were placed in acrylic resin and sectioned into 1 mm transverse slices. A POBS test was conducted using a universal testing machine, and the mode of bond failure was assessed at 4× magnification using a stereomicroscope. Six specimens from each group were selected for SEM-EDX examination to evaluate dentinal tubule penetration. The data were analysed using analysis of variance and Tukey and Bonferroni post hoc tests. Results: The POBS tests revealed higher values for Ah Plus in comparison to both calcium silicate sealers (p < 0.001), while FKG Hi-Flow showed superior results to Ah Bio (p < 0.001). The cohesive mode of failure was prevalent in all three groups. Conclusions: In conclusion, the resin-based sealer showed higher bond strength and better dentinal tubule penetration than the two calcium silicate sealers tested, while FKG Hi-Flow outperformed AH Bio. Full article

Introduction: Root dentin is a porous and complex dental surface that may have irregularities and deposits of organic material. To achieve an effective bond between restorative materials and root dentin, it is necessary that the restorative materials adhere intimately to the dentin surface. Metalloproteinases (MMPs) are a group of proteolytic enzymes that perform an important role in degrading the extracellular matrix and remodeling connective tissue. The aim of this research was to determine the scientific evidence available on the role played by MMPs in adhesion to root dentin and their putative inhibitors. Materials and Methods: Several techniques have been used to evaluate the presence of MMPs in the root dentin of human and bovine teeth, such as Western blot, immunohistochemistry, immunofluorescence, and zymography, the latter also being used together with the EnzCheck assay to evaluate the inhibitory effect of adhesion protocols on the activity of root MMPs in vitro. Results: When analyzing the databases, 236 articles were found, 12 of which met the selection criteria. The variables analyzed were articles that evaluated different MMP inhibitors in root dentin. Conclusions: In the adhesion to radicular dentin, MMPs have a crucial role in the degradation of the extracellular matrix of dentin and the remodeling of the dentin surface because excessive MMP activity can be harmful to dental health, since excessive degradation of the extracellular matrix of dentin can weaken the tooth structure and decrease fracture resistance. Therefore, it is important to monitor MMP activity during root dentin bonding procedures. Full article

The aim of this study was to evaluate the effects of mechanized final irrigation protocols (XPE, XP-Endo Finisher; XPC, XP-Clean; and ECL, Easy Clean) compared to PUI (passive ultrasonic irrigation) on the debris incidence and open dentinal tubules, and their effects on the adhesion interface after 48 h and 6 months. One hundred twenty maxillary central incisors were submitted to chemical–mechanical preparation using a rotary instrument and 2.5% sodium hypochlorite. Specimens were distributed in 4 groups (n = 30) in accordance with the mechanized final irrigation protocol: XPE, XPC, ECL, or PUI. Forty specimens (n = 10/group) were submitted to SEM analysis to evaluate the residue incidence and dentin open tubules. The other specimens were obturated using Bio-C Sealer and submitted to push-out bond strength and adhesive failure mode evaluations in the cervical, middle, and apical thirds after 48 h or 6 months (n = 10/group). Only in the apical third, ECL presented the highest residue incidence and fewer open dentinal tubules when compared to the XPE, XPC, and PUI groups (p < 0.05). In the cervical and middle root thirds, no significant differences were observed regardless of the group evaluated (p > 0.05). After 48 h, ECL resulted in the lowest bond strength only in the apical third (p < 0.05), while the XPE, XPC, and PUI groups remained similar in the cervical and middle thirds (p > 0.05). At 6 months, all groups showed lower bond strength values regardless of the root third evaluated, but ECL showed the lowest bond strength in the apical and middle root thirds when compared to the other groups (p < 0.05). The ECL protocol did not provide adequate residue removal on the apical radicular third and negatively affected the longevity of endodontic obturation using a calcium silicate-based sealer. Full article

Background: Using endodontic sealers with long-term antimicrobial properties can increase the success of endodontic treatment. This study aimed to assess the antimicrobial activity over time of two calcium silicate (CS)-based sealers, AH Plus Bioceramic and BioRoot RCS, and to compare them with an epoxy resin-based sealer, AH Plus Jet, against mature polymicrobial biofilms grown on human radicular dentin. Methods: The antimicrobial activity of the sealers was tested using a direct contact test after 1 and 6 weeks of contact with the biofilms. Cell viability was determined by the adenosine triphosphate (ATP) method and flow cytometry (FC). The results of the ATP test were analyzed using an ANOVA with Welch’s correction, followed by the Games–Howell test. The number of cells with damaged membranes obtained by FC in each period was compared by means of an ANOVA and Duncan’s test. For the comparison between times, a Student’s t-test was used. Results: Globally, after a week of contact, the epoxy resin-based sealer obtained the best results. However, at 6 weeks, the two CSs showed the highest antimicrobial efficacy, with a significant increase in this activity over time. Conclusions: Calcium silicate-based sealers exert long-term antimicrobial activity against endodontic biofilms. Full article

This study aimed to assess the adaptability and penetration depth capacity of recent bioceramic systems, including regular EndoSequence (BC) versus HiFlow (BCH) sealers in the presence of BC points. A total of 54 single-rooted teeth were instrumented and obturated with either the cold or warm compaction technique (n = 9), using either BC, BCH, or AH Plus (AHP) combined with BC points. The adaptation, film thickness, and gaps/voids were evaluated by scanning electron microscopy. The sealer/dentin interface was evaluated by Raman spectroscopy, and depth penetration was evaluated by a confocal laser scanning microscope. According to the normality test, the data were statistically analyzed by ANOVA or Kruskal–Wallis and Mann–Whitney U tests at p < 0.05. BCH sealer showed the significantly thinnest film with the greatest flow (p > 0.001), with further improvement when subjected to the warm compaction technique. Moreover, it exhibited close adaptation with deep penetration into radicular dentin, forming a tag-like structure. The Raman spectra also indicated close contact with the dentin surface. The use of BC sealer with BC points exhibited homogenous, single-unit obturation, either with a cold or warm technique. Furthermore, the use of the warm compaction technique with BCH sealer achieved a gap-free interface associated with tag-like structures, which exhibit the monoblock phenomenon. Full article

(1) Background: The objective of this in vitro study was to evaluate the impact of different etching times and ethanol pre-treatments on the immediate bond strength of a hydrophilic multi-mode universal adhesive (Clearfil Universal Bond Quick, Kuraray, UBQ) and on the consequent gelatinolytic activity of metalloproteinases (MMPs) on radicular dentin. (2) Methods: Sixty single-root teeth were selected and divided into four groups according to the adhesive protocol applied for fiber post cementation: (G1) 15 s H₃PO₄ application + UBQ; (G2) 30 s H₃PO₄ application + UBQ; (G3) 15 s H₃PO₄ application + ethanol pre-treatment + UBQ; (G4) 30 s H₃PO₄ + ethanol pre-treatment + UBQ. After adhesive procedures, fiber posts were luted into the post space with a dual-curing cement (DC Core, Kuraray) and light-cured for 40 s. To perform the push-out test and nanoleakage analyses for both coronal end apical areas, 1 mm slices were prepared, following a 24 h storage period in artificial saliva. Additionally, an in situ zymographic assay was conducted to explore endogenous MMP activity within the radicular layer. Results were statistically analyzed with ANOVA and Tukey post hoc tests. Statistical significance was set at p < 0.05. (3) Result: ANOVA revealed a statistically significant difference in push-out bond strength related to the pre-treatment variable but did not highlight any significance of etching time. Specimens pre-treated with ethanol wet bond application showed higher bond strength (p < 0.01). In situ zymography quantification analyses revealed that all tested groups, independently of etching time end ethanol pre-treatment, activated MMP gelatinolytic activity. A significant increase in MMP activity was detected for the 30 s etching time. However, ETOH pre-treatment significantly reduced MMP activity within the adhesive interface (p < 0.01). (4) Conclusions: The tested adhesive showed similar results regardless of the etching time protocol. The gelatinolytic activity of MMPs was observed in all the groups. Further investigations and extended follow-ups are required to validate the results of the present study in vivo. Full article

Marginal adaptation and internal porosity characteristics of root-end filling materials are important factors determining their clinical performance. The aim of this study was to quantitatively evaluate the marginal adaptation to radicular dentin (interfacial void volume) and internal porosity volume of a novel mineral trioxide aggregate brand using micro-CT analysis. Ten extracted upper central incisors were selected, instrumented, and obturated. Roots were resected at the apical 3 mm, and root-end cavities were prepared ultrasonically and filled with Harvard MTA. SkyScan 1272 micro-CT equipment was used to scan the specimens at a resolution of 6 μm, and three-dimensional images were reconstructed. All volumetric porosity parameters of the tested material were calculated in absolute (mm³) and relative values (%), as follows: open porosity volume (OPV), closed porosity volume (CPV), and total porosity volume (TPV). The mean OPV and OPV% found for Harvard MTA were 0.0268 mm³ and 0.91%, respectively. The mean CPV and CPV% were 0.0283 mm³ and 0.94%, respectively. The TPV and TPV% were 0.0569 mm³ and 1.85%. There was no significant difference between the OPV% and CPV% (p < 0.05). In conclusion, when applied as a retrofilling material, Harvard MTA exhibited excellent marginal adaptation to the dentin with minimal interfacial voids and internal microporosity. Therefore, this new calcium silicate brand may be considered an efficient alternative to conventional products. Full article

The aim of this study is to assess and analyze the intratubular penetration of the intracanal medications nitrofurantoin (Nit), triple antibiotic paste (TAP), and calcium hydroxide (CH). Sixty freshly extracted single-rooted teeth were acquired and decoronated to a standard length of 15 mm. To prepare specimens up to size F3, rotary ProTaper instrumentation was employed. The prepared teeth were divided into three groups, each of which received one of the tested intracanal medicaments: Group I (calcium hydroxide), Group II (triple antibiotic paste), and Group III (nitrofurantoin). Using a size #30 Lentulo spiral, a freshly prepared therapeutic paste was placed into the canals, and the intracanal medicaments were allowed to set in the incubator at 100% humidity. The samples were subsequently sliced perpendicularly to their long axis using a precision saw and assessed under a scanning electron microscope to assess the depth of penetration of intracanal medicaments at the coronal, middle, and apical portions of the root canal dentin. The data were analyzed using one-way ANOVA and Tukey’s post hoc test. The statistical analysis revealed a significant difference between the experimental groups in the quantity and depth of sealer penetration (p < 0.05). In particular, as compared to the Nit group, both the CH and TAP groups had significantly smaller penetration areas (p < 0.05). In conclusion, this ongoing investigation indicates that nitrofurantoin penetrated dentinal tubules better than calcium hydroxide or triple antibiotic paste. Full article

This investigation aimed to assess, through a systematic review, the effect of non-thermal plasma treatments on root canal sealers’ adhesion to dentin. This study followed the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A literature search was undertaken without limits on time or language, until May 2023, in PubMed–MEDLINE, Scopus, Web of Science, OpenGrey, and three endodontic journals. The included studies underwent quality assessment and data extraction. Out of an initial 188 articles, 4 studies were included. Three of these studies based the adhesion ability on the push-out test in human extracted teeth, while the other used bovine dentin samples to measure the contact angle with the sealer (wettability). While there was no consensus about the effect of non-thermal plasma (NTP) on the AH Plus sealer’s adhesion to radicular dentin, NTP seemed to positively influence the adhesion ability of BioRoot RCS and Endosequence BC. The findings of the present review should be interpreted cautiously due to the scarcity of studies on the topic. The NTP parameters should be optimized to obtain a stronger evidence base in endodontics on its role as an adjuvant tool to increase sealers’ adhesion to dentin. Full article