This study aimed to evaluate the physical-mechanical, chemical, and biological properties of graphene-reinforced glass ionomer cements (GICs).

Different proportions of graphene powder were incorporated into 2 high-viscosity self-curing GIC, Ketac Molar (G_Ketac) and Fuji IX (G_Fuji), in 4 different concentrations: 0.5%, 1%, 2%, and 5%. The control groups included the GICs without graphene. Experiments were performed to analyze linear (Ra) and volumetric roughness (Sa), antimicrobial activity, radiopacity, fluoride release, microhardness, solubility, and water sorption. Data were analyzed using Kruskal-Wallis, Mann-Whitney, Wilcoxon, analysis of variance, and Tukey’s test (p ≤ 0.05).

The G_Ketac 0% and G_Fuji0% groups presented higher Ra (4.05 and 2.72) and Sa (4.76 and 5.16), respectively. No inhibition zone was observed, and the incorporation of graphene reduced radiopacity. Moreover, there was no influence on the solubility and water sorption after 21 days. A greater fluoride release was observed in the period of 7 days for most of the groups. After 21 days, G_Ketac 5%, 2%, and 1% presented higher releasing than 0% and 0.5% (p ≤ 0.05).

The graphene incorporation improved the microhardness of GICs in lower concentrations. Graphene incorporation to GICs modified some physical-mechanical, and chemical, but not affected biological properties.

The aim of this study was to compare the effects of different polymerization strategies and the effectiveness of finishing and polishing procedures of composite resins on color stability.

The samples were divided into 4 main groups according to the polymerization strategy, and all groups except the control group received surface treatment. Each group was subsequently divided into 3 subgroups respectively: Kuraray Clearfil Majesty ES-2 Classic, Premium and Universal. Approximately 24 hours after preparation of the samples, they were immersed for 7 days in a coffee solution. A first color measurement was performed after the preparation of the samples, the second measurement was performed after 7 days in the coffee solution. All measurements were carried out using a dental spectrophotometer to assess the CIE L* a* b* color parameters.

There was a statistically significant difference between ΔE values for different procedures (p = 0.003); in particular, the differences were found only between the groups that received surface treatment and the control group. In addition, a statistically significant difference was observed between the values of ΔE for different composites in the different procedure groups.

Spectrophotometric analysis showed that the additional photopolymerization and oxygen inhibition procedures did not yield better results in relation to color stability. In addition, finishing and polishing provided better color stability compared to not performing these procedures.

The aim of the current study was to evaluate the effect of polishing systems and surface sealant on the color stability and whiteness index of single-shade resin composites after staining and bleaching.

Three single-shade (Omnichroma, Charisma Diamond One, Zenchroma) and one multi-shade (Filtek Z250) materials were tested. From each resin composite, 40 specimens were prepared. The specimens were divided into 4 subgroups (n = 10) according to the surface treatments: 1-step polishing, 1-step + Biscover LV, 2-step polishing, and 2-step polishing + Biscover LV. Color differences (ΔE₀₀) were calculated after being immersed in the coffee solution for 12 days. After the staining, the specimens were immersed in a whitening mouthrinse (Crest-3D White) for 12 hours. Whiteness index differences (∆WI_D = WI_D after staining − WI_D after bleaching) values were recorded. The generalized linear model was used for analysis (p < 0.05).

The lowest and highest ΔE₀₀ values were found for Zenchroma and Charisma Diamond One respectively. Sealed groups indicated higher ΔE₀₀ values than nonsealed groups with significant differences (p = 0.008). The lowest and highest ΔWI_D values were found for Zenchroma and Charisma Diamond One respectively. Sealed groups indicated lower ΔWI_D values than nonsealed groups with significant differences (p = 0.022).

The use of surface sealant increased the discoloration and showed less whiteness change in resin materials. When the 1-step was compared with the 2-step polishing, the effects on the color stability and whiteness index values of the resin materials were similar.

This study aimed to investigate the frequency and type of endodontic procedural errors in cases indicated for retreatment through cone-beam computed tomography (CBCT) analysis.

The sample consisted of 96 CBCT scans, encompassing 122 permanent teeth with fully formed roots. Errors included perforation, instrument fracture, canal transportation, missed canals, and inadequate apical limit of filling. Additionally, potential risk factors were analyzed and subjected to statistical modeling.

The most frequent procedural error observed was the inadequate apical limit of filling, followed by canal transportation, perforation, missed canal, and instrument fracture. Statistically significant associations were identified between various procedural errors and specific factors. These include canal transportation and root canal wall, with the buccal wall being the most commonly affected; missed canal and tooth type, particularly the palatine and second mesiobuccal canal canals; inadequate apical limit of filling and root curvature, showing a higher deviation to the mesial direction in severely curved canals; inadequate apical limit of filling and the presence of calcifications, with underfilling being the most frequent; canal transportation and periapical lesion, notably with deviation to the buccal direction; and the direction of perforation and periapical lesion, most frequently occurring to buccal direction.

CBCT emerges as a valuable tool in identifying procedural errors and associated factors, crucial for their prevention and management.

This cross-sectional study evaluated the prevalence of apical periodontitis (AP) and the technical quality of root canal fillings in an adult Kuwaiti subpopulation using cone-beam computed tomography (CBCT) images.

Two experienced examiners analyzed 250 CBCT images obtained from Kuwaiti patients aged 15–65 years who attended government dental specialist clinics between January 2019 and September 2020. The assessment followed the radiographic scoring criteria proposed by De Moor for periapical status and the technical quality of root canal filling. Chi-square and Fisher’s exact tests were used for statistical analysis, with significance level set at p < 0.05.

Among the 2,762 examined teeth, 191 (6.91%) exhibited radiographic signs of AP, and 176 (6.37%) had undergone root canal filling. AP prevalence in root canal-treated teeth was 32.38%, with a significant difference between males and females. Most of the endodontically treated teeth exhibited adequate root canal filling (71.5%).

The study demonstrated a comparable prevalence of AP and satisfactory execution of root canal treatment compared to similar studies in different countries.

This study aimed to evaluate the impact of substrate color and interface distance on the color adjustment of 2 single-shade composites, Vittra APS Unique and Charisma Diamond One.

Dual disc-shaped specimens were created using Vittra APS Unique or Charisma Diamond One as the center composite, surrounded by shaded composites (A1 or A3). Color measurements were taken with a spectrophotometer against a gray background, recording the color coordinates in the CIELAB color space. Illumination with a light-correcting device and image acquisition using a polarizing filter-equipped cell phone were performed on specimens over the same background. Image processing software was used to measure the color coordinates in the center and periphery of the inner composite and in the outer composite. The color data were then converted to CIELAB coordinates and adjusted using data from the spectrophotometer. Color differences (ΔE₀₀) between the center/periphery of single-shade and outer composites were calculated, along with color changes in single-shade composites caused by different outer composites. Color differences for the inner composites surrounded by A1 and A3 were also calculated. Data were analyzed using repeated-measures analysis of variance (α = 0.05).

The results showed that color discrepancies were lowest near the interface and when the outer composite was whiter (A1). Additionally, Charisma Diamond One exhibited better color adjustment ability than Vittra APS Unique.

Color discrepancies between the investigated single-shade composites diminished towards the interface with the surrounding composite, particularly when the latter exhibited a lighter shade.

This study aimed to determine the effects of 1-rooted mandibular second molar (MnSM) teeth on root canal anatomy complexities of the mandibular central incisor (MnCI), mandibular lateral incisor (MnLI), mandibular canine (MnCn), mandibular first premolar (MnFP), mandibular second premolar (MnSP), and mandibular first molar (MnFM) teeth.

Cone-beam computed tomography images of 600 patients with full lower dentition were examined. Individuals with 1-rooted MnSMs were determined, and the complexity of root canal anatomy of other teeth was compared with individuals without 1-rooted MnSMs (Group-1; subjects with at least one 1-rooted MnSM, Group-2; subjects with more than a single root in both MnSMs). A second canal in MnCIs, MnLIs, MnCns, MnFPs, and MnSPs indicated a complicated root canal. The presence of a third root in MnFMs was recorded as complicated.

The prevalence of 1-rooted MnSMs was 12.2%, with the C-shaped root type being the most prevalent (9%). There were fewer complicated root canals in MnCIs (p = 0.02), MnLIs (p < 0.001), and MnFPs (p < 0.001) in Group 1. The other teeth showed no difference between the groups (p > 0.05). According to logistic regression analysis, 1-rooted right MnSMs had a negative effect on having complex canal systems of MnLIs and MnFPs. Left MnSMs were explanatory variables on left MnLIs and both MnFPs.

In individuals with single-rooted MnSMs, a less complicated root canal system was observed in all teeth except the MnFMs.

This study aimed to compare the effectiveness of a single-file reciprocating system (WaveOne Gold, WOG) and a multi-file rotary system (ProTaper Universal Retreatment, PTUR) in removing canal filling from severely curved canals and to evaluate the possible adjunctive effects of XP-Endo Finisher (XPF), the Self-Adjusting File (SAF), and an erbium, chromium: yttrium, scandium, gallium garnet (Er,Cr:YSGG) laser using micro-computed tomography (μCT).

Sixty-six curved mandibular molars were divided into 2 groups based on the retreatment technique and then into 3 based on the supplementary method. The residual filling volumes and root canals were evaluated with μCT before and after retreatment, and after the supplementary steps. The data were statistically analyzed with the t-test, Mann-Whitney U test, analysis of covariance, and factorial analysis of variance (p < 0.05).

PTUR and WOG showed no significant difference in removing filling materials (p > 0.05). The supplementary techniques were significantly more effective than reciprocating or rotary systems only (p < 0.01). The supplementary steps showed no significant differences in canal filling removal effectiveness (p > 0.05), but XPF showed less dentin reduction than the SAF and Er,Cr:YSGG laser (p < 0.01).

The supplementary methods significantly decreased the volume of residual filling materials. XPF caused minimal changes in root canal volume and might be preferred for retreatment in curved root canals. Supplementary approaches after retreatment procedures may improve root canal cleanliness.

PROSPERO Identifier: CRD42022349891

The formation of new bone by periosteum due to an insult is called periosteal bone reaction (PBR). This study assessed the cone beam computed tomography (CBCT) patterns of periosteal bone reactions associated with periapical inflammatory lesion (apical periodontitis/periapical rarefying osteitis).

Twenty-two small field of view CBCT images of patients with PBR were selected from a database of a private practice limited to endodontics. The volume of the periapical inflammatory lesion, the presence of cortical fenestration, the distance of the root apices to the affected cortex, and the location, pattern, and longest diameter of the periosteal reaction were recorded. Statistical analysis was performed using Wilcoxon Ranksum, Fischer’s exact, Spearman Correlation Coefficient, and paired t-test.

In all cases, periosteal bone reaction manifested as either parallel (90.9%) or irregular (9.1%). No correlation was found between periapical inflammatory lesion volume and the periosteal reaction's longest diameter (p > 0.05). Cortical fenestration was noted in 72.7% of the cases. In addition, the findings showed that periosteal reactions were located mostly on the buccal and were present 53.8% and 100% of the time in the mandible and maxilla, respectively.

The periosteal reactions of endodontic origin had a nonaggressive form (i.e., parallel or irregular), and none of the lesions resulted in a periosteal reaction with an ominous Codman’s triangle or spicule pattern.

The aim of this study was to evaluate the influence of peak kilovoltage (kVp) and a metal artifact reduction (MAR) tool on image quality and the diagnosis of vertical root fracture (VRF) in cone-beam computed tomography (CBCT).

Twenty single-rooted human teeth filled with an intracanal metal post were divided into 2 groups: control (n = 10) and VRF (n = 10). Each tooth was placed into the socket of a dry mandible, and CBCT scans were acquired using a Picasso Trio varying the kVp (70, 80, 90, or 99), and the use of MAR (with or without). The examinations were assessed by 5 examiners for the diagnosis of VRF using a 5-point scale. A subjective evaluation of the expression of artifacts was done by comparing random axial images of the studied protocols. The results of the diagnoses were analyzed using 2-way analysis of variance and the Tukey post hoc test, the subjective evaluations were compared using the Friedman test, and intra-examiner reproducibility was evaluated using the weighted kappa test (α = 5%).

The kVp and MAR did not influence the diagnosis of VRF (p > 0.05). According to the subjective classification, the 99 kVp protocol with MAR demonstrated the least expression of artifacts, while the 70 kVp protocol without MAR led to the most artifacts.

Protocols with higher kVp combined with MAR improved the image quality of CBCT examinations. However, those factors did not lead to an improvement in the diagnosis of VRF.

This study evaluated the efficiency of WaveOne Primary files (Dentsply Sirona) for removing root canal fillings with 2 types of movement: reciprocating (RCP) and continuous counterclockwise rotation (CCR).

Twenty mandibular incisors were prepared with a RCP instrument (25.08) and filled using the Tagger hybrid obturation technique. The teeth were retreated with a WaveOne Primary file and randomly allocated to 2 experimental retreatment groups (n = 10) according to movement type: RCP and CCR. The root canals were emptied of filling material in the first 3 steps of insertion, until reaching the working length. The timing of retreatment and procedure errors were recorded for all samples. The specimens were scanned before and after the retreatment procedure with micro-computed tomography to calculate the percentage and volume (mm³) of the residual filling material. The results were statistically evaluated using paired and independent t-tests, with a significance level set at 5%.

No significant difference was found in the timing of filling removal between the groups, with a mean of 322 seconds (RCP) and 327 seconds (CCR) (p < 0.05). There were 6 instrument fractures: 1 in a RCP motion file and 5 in continuous rotation files. The volumes of residual filling material were similar (9.94% for RCP and 15.94% for CCR; p > 0.05).

The WaveOne Primary files used in retreatment performed similarly in both RCP and CCR movements. Neither movement type completely removed the obturation material, but the RCP movement provided greater safety.

This study evaluated the effects of high-plasticity mineral trioxide aggregate (MTA-HP) on the activity of M1 and M2 macrophages, compared to white MTA (Angelus).

Peritoneal inflammatory M1 (from C57BL/6 mice) and M2 (from BALB/c mice) macrophages were cultured in the presence of the tested materials. Cell viability (MTT and trypan blue assays), adhesion, phagocytosis, reactive oxygen species (ROS) production, and tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β production were evaluated. Parametric analysis of variance and the non-parametric Kruskal-Wallis test were used. Results were considered significant when p < 0.05.

The MTT assay revealed a significant decrease in M1 metabolism with MTA-HP at 24 hours, and with MTA and MTA-HP later. The trypan blue assay showed significantly fewer live M1 at 48 hours and live M2 at 48 and 72 hours with MTA-HP, compared to MTA. M1 and M2 adherence and phagocytosis showed no significant differences compared to control for both materials. Zymosan A stimulated ROS production by macrophages. In the absence of interferon-γ, TNF-α production by M1 did not significantly differ between groups. For M2, both materials showed higher TNF-α production in the presence of the stimulus, but without significant between-group differences. Likewise, TGF-β production by M1 and M2 macrophages was not significantly different between the groups.

M1 and M2 macrophages presented different viability in response to MTA and MTA-HP at different time points. Introducing a plasticizer into the MTA vehicle did not interfere with the activity of M1 and M2 macrophages.

This study evaluated the effect of different nanoparticulated zinc oxide (nano-ZnO) and conventional-ZnO ratios on the physicochemical properties of calcium aluminate cement (CAC).

The conventional-ZnO and nano-ZnO were added to the cement powder in the following proportions: G1 (20% conventional-ZnO), G2 (15% conventional-ZnO + 5% nano-ZnO), G3 (12% conventional-ZnO + 3% nano-ZnO) and G4 (10% conventional-ZnO + 5% nano-ZnO). The radiopacity (R_ad), setting time (S_et), dimensional change (D_c), solubility (S_ol), compressive strength (C_st), and pH were evaluated. The nano-ZnO and CAC containing conventional-ZnO were also assessed using scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Radiopacity data were analyzed by the 1-way analysis of variance (ANOVA) and Bonferroni tests (p < 0.05). The data of the other properties were analyzed by the ANOVA, Tukey, and Fisher tests (p < 0.05).

The nano-ZnO and CAC containing conventional-ZnO powders presented particles with few impurities and nanometric and micrometric sizes, respectively. G1 had the highest R_ad mean value (p < 0.05). When compared to G1, groups containing nano-ZnO had a significant reduction in the S_et (p < 0.05) and lower values of D_c at 24 hours (p < 0.05). The C_st was higher for G4, with a significant difference for the other groups (p < 0.05). The S_ol did not present significant differences among groups (p > 0.05).

The addition of nano-ZnO to CAC improved its dimensional change, setting time, and compressive strength, which may be promising for the clinical performance of this cement.

This study investigated the prevalence and characteristics of external cervical resorption (ECR) regarding sex, age, tooth, stages of progression, and portal of entry, using cone-beam computed tomography (CBCT) scans.

CBCT scans of 1,313 patients from a Brazilian subpopulation comprising 883 female and 430 male patients (mean age, 55.2 years), acquired using a PreXion 3D CBCT unit, were evaluated. All permanent teeth included in the scans were evaluated for the presence of ECR according to the 3-dimensional classification and the portal of entry. The association between the presence of ECR and the factors studied was assessed using the χ² test. Intra-observer agreement was analyzed with the kappa test (α = 0.05).

In total, 6,240 teeth were analyzed, of which 84 (1.35%) were affected by ECR. A significant association was found between the presence of ECR and sex, with a higher prevalence in male patients (p = 0.002). The most frequently affected teeth were the mandibular and maxillary central incisors. The most common height was the mid-third of the root. For the portal of entry, 44% of cases were on the proximal surfaces, 40.5% on the lingual/palatal surface and 15.5% on the buccal surface. Intra-observer agreement was excellent.

The prevalence of ECR was 1.35%, with a higher prevalence in male patients and a wide age distribution. The mandibular and maxillary central incisors were the most commonly affected teeth, and cases of ECR most frequently showed a height into the mid-third of the root and proximal entry.

This study investigated the cytotoxicity, radiopacity, pH, and dentinal tubule penetration of a paste of 1.0% calcium-doped zinc oxide nanocrystals (ZnO:1.0Ca) combined with propylene glycol (PRG) or polyethylene glycol and propylene glycol (PEG-PRG).

The pastes were prepared by mixing calcium hydroxide [Ca(OH)₂] or ZnO:1.0Ca with PRG or a PEG-PRG mixture. The pH was evaluated after 24 and 96 hours of storage in deionized water. Digital radiographs were acquired for radiopacity analysis and bubble counting of each material. The materials were labeled with 0.1% fluorescein and applied to root canals, and images of their dentinal tubule penetration were obtained using confocal laser scanning microscopy. RAW264.7 macrophages were placed in different dilutions of culture media previously exposed to the materials for 24 and 96 hours and tested for cell viability using the MTT assay. Analysis of variance and the Tukey test (α = 0.05) were performed.

ZnO:1.0Ca materials showed lower viability at 1:1 and 1:2 dilutions than Ca(OH)₂ materials (p < 0.0001). Ca(OH)₂ had higher pH values than ZnO:1.0Ca at 24 and 96 hours, regardless of the vehicle (p < 0.05). ZnO:1.0Ca pastes showed higher radiopacity than Ca(OH)₂ pastes (p < 0.01). No between-material differences were found in bubble counting (p = 0.0902). The ZnO:1.0Ca pastes had a greater penetration depth than Ca(OH)₂ in the apical third (p < 0.0001).

ZnO:1.0Ca medicaments presented higher penetrability, cell viability, and radiopacity than Ca(OH)₂. Higher values of cell viability and pH were present in Ca(OH)₂ than in ZnO:1.0Ca.

This study aimed to evaluate the prevalence of apical periodontitis (AP) in the mesiobuccal roots of root canal-treated maxillary molars.

One thousand cone-beam computed tomography images of the teeth were examined by 2 dental specialists in oral radiology and endodontics. The internal anatomy of the roots, Vertucci’s classification, quality of root canal treatment, and presence of missed canals were evaluated; additionally, the correlation between these variables and AP was ascertained.

A total of 1,000 roots (692 first molars and 308 second molars) encompassing 1,549 canals were assessed, and the quality of the root canal filling in the majority (56.9%) of the canals was satisfactory. AP was observed in 54.4% of the teeth. A mesiolingual canal in the mesiobuccal root (MB2 canal) was observed in 54.9% of the images, and the majority (83.5%) of these canals were not filled. Significant associations were observed between the presence of an MB2 canal and the quality of the root canal filling and the presence of AP.

AP was detected in more than half of the images. The MB2 canals were frequently missed or poorly filled.

This study aimed to evaluate the influence of inorganic composition and filler particle morphology on the mechanical properties of different self-adhesive resin cements (SARCs).

Three SARCs including RelyX Unicem-2 (RUN), Maxcem Elite (MAX), and Calibra Universal (CAL) were tested. Rectangular bar-shaped specimens were prepared for flexural strength (FS) and flexural modulus (FM) and determined by a 3-point bending test. The Knoop microhardness (KHN) and top/bottom microhardness ratio (%KHN) were conducted on the top and bottom faces of disc-shaped samples. Sorption (Wsp) and solubility (Wsl) were evaluated after 24 hours of water immersion. Filler morphology was analyzed by scanning electron microscopy and X-ray energy dispersive spectroscopy (EDS). FS, FM, %KHN, Wsp, Wsl, and EDS results were submitted to 1-way analysis of variance and Tukey’s post-hoc test, and KHN also to paired t-test (α = 0.05).

SARC-CAL presented the highest FS value, and SARC-RUN presented the highest FM. SARC-MAX and RUN showed the lowest Wsp and Wsl values. KHN values decreased from top to bottom and the SARCs did not differ statistically. Also, all resin cements presented carbon, aluminum, and silica in their composition. SARC-MAX and RUN showed irregular and splintered particles while CAL presented small and regular size particles.

A higher mechanical strength can be achieved by a reduced spread in grit size and the filler morphology can influence the KHN, as well as photoinitiators in the composition. Wsp and Wsl can be correlated with ions diffusion of inorganic particles.

This study aimed to evaluate in vitro the effects of the self-adhesive resin cements RelyX U200 (3M ESPE) and seT PP (SDI Limited) on murine macrophages and the interference of the photoactivation.

Cell viability assays, cell adherence, yeast phagocytosis of Saccharomyces boulardii and production of reactive oxygen species (ROS) were performed in the presence of capillaries containing the respective self-adhesive cement when photoactivated or not.

After long periods of contact, both types of cements, when not photoactivated, are more cytotoxic for macrophages. The seT PP cement when only chemically activated seems to interfere more negatively in the process of phagocytosis of yeasts S. boulardii. Both types of cements interfere in the cell adhesion process, independent of photoactivation. None of the types of cements tested was able to induce the production of ROS.

Our results highlight the great importance of the photoactivation of self-adhesive resin cements in the dental clinic, since RelyX U200, when photoactivated, presented the best results within the evaluated parameters.

The aim of this study was to evaluate and compare the apical constriction (AC) and apical canal morphology of maxillary first and second molars, using micro-computed tomography (micro-CT).

The anatomical features of 313 root canals from 41 maxillary first molars and 57 maxillary second molars of patients with known age and sex were evaluated using micro-CT, with a resolution of 26.7 µm. The factors evaluated were the presence or absence of AC, the morphotypes, bucco-lingual dimension, mesio-distal dimension, and the profile (shape) of AC and the apical root canal. The apical root canal dimensions, location of the apical foramen (AF), AC to AF distance, and presence of accessory canals in the apical 5 mm were also assessed. Descriptive and analytical statistics were used for data evaluation.

AC was present in all 313 root canals. Patients’ age and sex did not significantly impact either AC or the apical canal dimensions. The most common AC morphotype detected was the traditional (single) constriction (52%), followed by the parallel (29%) morphotype. The mean AC dimensions in maxillary first molars were not significantly different from those in maxillary second molars. Sixty percent of AF were located within 0.5 mm from the anatomic apex.

The most common morphotype of AC detected was the traditional constriction. Neither patients’ age nor sex had a significant impact on the dimensions of the AC or the apical root canal. The majority of AF (60%) were located within 0.5 mm from the anatomic apex.

This study evaluated the efficacy of 3 reciprocating systems and the effects of 2 instruments for irrigant activation on filling material removal.

Forty mesiobuccal roots of maxillary molars were prepared up to size 25.06 and obturated. Micro-computed tomography (micro-CT) examination #1 was performed. Teeth were then divided into 4 groups (n = 10), according to the retreatment protocol: (1) manual, (2) Reciproc Blue, (3) WaveOne Gold, and (4) X1 Blue. Micro-CT examinations #2 and #3 were performed after filling removal and repreparation, respectively. Next, all teeth were divided into 2 new groups (n = 20) according to the irrigant activation protocol: XP Clean (XP Clean size 25.02) and Flatsonic (Flatsonic ultrasonic tip). Micro-CT examination #4 was performed after irrigant activation. Statistical analysis was performed with a significance level set at 5%.

WaveOne Gold removed a significantly greater amount of filling material than the manual group (p < 0.05). The time to reach the WL was similar for all reciprocating systems (p > 0.05). X1 Blue was faster than the manual group (p < 0.05). Only manual group improved the filling material removal after the repreparation stage (p < 0.05). Both activation protocols significantly improved the filling material removal (p < 0.05), without differences between them (p > 0.05).

None of the tested instruments completely removed the filling material. X1 Blue size 25.06 reached the working length in the shortest time. XP Clean and Flatsonic improved the filling material removal.

This study aimed to investigate the color stability, solubility, and surface characteristics of 3 calcium silicate-based cements (CSCs) after immersion in different solutions.

ProRoot white mineral trioxide aggregate (MTA), Biodentine, and Endosequence Root Repair Material (ERRM) were placed in cylindrical molds and stored at 37°C for 24 hours. Each specimen was immersed in distilled water, 5% sodium hypochlorite (NaOCl), 2% chlorhexidine, or 0.1% octenidine hydrochloride (OCT) for 24 hours. Color changes were measured with a spectrophotometer. Solubility was determined using an analytical balance with 10⁻⁵ g accuracy. The surface characteristics were analyzed using scanning electron microscopy and energy-dispersive spectroscopy. Data were analyzed using 2-way analysis of variance, the Tukey test, and the paired t-test.

MTA exhibited significant discoloration in contact with NaOCl (p < 0.05). White precipitation occurred on the surfaces of Biodentine and ERRM after contact with the solutions, and none of the materials presented dark brown discoloration. All materials showed significant solubility after immersion in the solutions (p < 0.05), irrespective of the solution type (p > 0.05). The surface topography and elemental composition of the samples showed different patterns of crystal formation and precipitation depending on the solution type.

All materials presented some amount of solubility and showed crystal precipitation after contact with the solutions. Biodentine and ERRM are suitable alternatives to ProRoot MTA as they do not exhibit discoloration. The use of OCT can be considered safe for CSCs.

The aim of this study was to compare the color change of the Giomer resin composite (Beautifil-Bulk) by using photographs obtained with a smartphone (iPhone 6S) associated with Adobe Photoshop software (digital method), with the spectrophotometric method (Vita Easyshade) after immersion in different pigment solutions.

Twenty resin composite samples with a diameter of 15.0 mm and thickness of 1.0 mm were confectioned in A2 color (n = 5). Photographs and initial color readings were performed with a smartphone and spectrophotometer, respectively. Then, samples were randomly divided and subjected to cycles of immersion in distilled water (control), açai, Coke, and tomato sauce, 3 times a day, 20 minutes for 7 days. Later, new photographs and color readings were taken.

The analysis (2-way analysis of variance, Holm-Sidak, p < 0.05) demonstrated no statistical difference (p < 0.005) between the methods in all groups. Similar color changes were observed for all pigment solutions when using the spectrophotometric method. For the digital method, all color changes were clinically unacceptable, with distilled water and tomato sauce similar to each other and with statistical differences (p < 0.005) for Coke and açai.

Only the tomato sauce produced a color change above the acceptability threshold using both methods of color assessment. The spectrophotometric and digital methods produce different patterns of color change. According to our results, the spectrophotometric method is more recommended in color change assessment.

This study investigated the internal morphology of mesiobuccal (MB) roots of maxillary molars with a second mesiobuccal (MB2) canal.

Forty-seven maxillary first or second molars from Brazilians were scanned using micro-computed tomography. The following measurements were obtained from the MB roots: root thickness, root width, and dentin thickness of the buccal aspect of the first mesiobuccal (MB1) canal, between the MB1 and MB2 canals, and the palatal aspect of the MB2 and MB1 canals at 3 mm from the root apex and in the furcation region. For statistical analysis, the Student’s t-test and analysis of variance with the post-hoc Tukey test were used (α = 0.05).

In maxillary molars with an MB2 canal, MB roots were significantly thicker (p = 0.0014) and narrower (p = 0.0016) than in maxillary molars without an MB2 canal. The dentin thickness of the palatal aspect of the MB1 canal was also significantly greater than that of MB roots without an MB2 canal at 3 mm from the root apex (p = 0.0007) and in the furcation region (p < 0.0001). In the furcation region of maxillary molars with an MB2 canal, the dentin thickness between the MB1 and MB2 canals was significantly smaller than that in the buccal and palatal aspects (p < 0.0001).

The internal morphology of MB roots of maxillary molars with an MB2 canal revealed differences in dentin thickness, root diameter, and distance between the canals when compared with maxillary molars without an MB2 canal.

This study investigated the impact of micro-computed tomography (micro-CT)-based voxel size on the analysis of material/dentin interface voids and thickness of different endodontic cements.

Following root-end resection and apical preparation, maxillary premolars were filled with mineral trioxide aggregate (MTA), Biodentine, and intermediate restorative material (IRM) (n = 24). The samples were scanned using micro-CT (SkyScan 1272; Bruker) and the cement/dentin interface and thickness of materials were evaluated at voxel sizes of 5, 10, and 20 µm. Analysis of variance and the Tukey test were conducted, and the degree of agreement between different voxel sizes was evaluated using the Bland and Altman method (p < 0.05).

All materials showed an increase in thickness from 5 to 10 and 20 µm (p < 0.05). When evaluating the interface voids, materials were similar at 5 µm (p > 0.05), while at 10 and 20 µm Biodentine showed the lowest percentage of voids (p < 0.05). A decrease in the interface voids was observed for MTA and IRM at 20 µm, while Biodentine showed differences among all voxel sizes (p < 0.05). The Bland-Altman plots for comparisons among voxel sizes showed the largest deviations when comparing images between 5 and 20 µm.

Voxel size had an impact on the micro-CT evaluation of thickness and interface voids of endodontic materials. All cements exhibited an increase in thickness and a decrease in the void percentage as the voxel size increased, especially when evaluating images at 20 µm.