An automated method to analyze root filling voids and gaps using confocal microscopy images.

This study evaluated the feasibility of an automated method to delimit the required area to quantitatively analyze root filling voids and gaps from cross-sectional confocal laser scanning microscopy (CLSM) images. Root canals of maxillary canines were prepared with rotary instruments and filled by lateral compaction technique using gutta-percha and AH Plus sealer. The roots were stored (100% humidity, 37 °C) for a period of 24 h and then transversally sectioned to obtain 2-mm-thick slices from the apical and middle thirds. The areas corresponding to filling materials, gaps, and voids were manually delimited or automatically demarked by ImageJ software after converting the images to the RGB color system. Based on manual and automatic delimitations, the percentages of voids and gaps were calculated. Data of voids and gaps between middle and apical thirds were individually compared by paired t-test. Pearson`s correlation test was used to assess the correlation of data between the methods. Irrespective of the method of area delimitation, no difference was observed between the root thirds for both voids and gaps, while the p-values calculated for each method were similar. Almost perfect correlations between the methods were observed for both outcomes. The proposed method to automatically delimit the areas corresponding to filling material, voids, and gaps appears to be a valid method to facilitate the quantitative analysis of defects in root canal fillings using topographic CSLM images.

Impact of low-fusion gutta-percha cones used in variations of the continuous wave condensation technique with filling sealers based on bioceramic compounds on the quality of root canal filling.

To evaluate the impact on the quality of filling with of low-fusion and conventional gutta-percha cones. Thirty-six maxillary canines were prepared and divided into three groups: I-conventional cone with Downpack at 200 °C at 4 mm from the WL; II-low-fusion cone with Downpack at 100 °C up to 4 mm from the WL; III-low-fusion cone with Downpack at 100 °C up to 7 mm from the WL. Temperature variations were measured in thirds on the external surface of the root. The bond strength was evaluated using the push-out test. The adhesive interface was analyzed by scanning electron microscopy. The bond strength and the temperature variation data were analyzed using analysis of variance and the failure type using the chi-square test. The low-fusion cone group with 7 mm Downpack showed higher bond strength (4.2 ± 2.7) compared with conventional cones (2.8 ± 1.6) and low-fusion cones with 4 mm Downpack (2.9 ± 1.6) (p < 0.05), with occurrence of a higher number of adhesive failures to the filling material and mixed failures. Relative to temperature variation, there was less temperature change in the apical third, in the low-fusion cone with Downpack 7 mm (1.0 ± 1.0) (p < 0.05). The use of low-fusion cones allowed the continuous wave condensation technique to be performed at a lower depth of Downpack at 100 °C at 7 mm, with less heating in the apical third, without compromising the quality of filling. Using gutta-percha cones with low fusion, which permits a lower condensation temperature and reduced Downpack depth, maintains the quality of filling, in order to minimize possible damage to the periapical tissues.

Identification and classification of pulp calcifications in posterior teeth according to dental condition using digital panoramic radiography and cone beam CT.

OBJECTIVE: To compare digital panoramic radiography (DPR) and cone beam CT (CBCT) in the detection and classification of pulp calcifications in posterior teeth in relation to tooth condition and its location. METHODS: Two hundred and fifty patients with simultaneous DPR and CBCT scans were selected from a dental image bank. For each posterior tooth, its condition was registered (healthy, restored, or decayed). The presence of calcifications was assessed and classified according to location (coronal or radicular) and type (total obliteration, partial obliteration, narrowing, and no calcification). Chi-square and McNemar tests were used to compare DPR and CBCT results, with a significance level of 5%. DPR diagnostic values were calculated using CBCT as reference. RESULTS: Decayed and restored teeth showed a significantly (P < .001) higher prevalence of pulp calcifications than healthy teeth in both imaging exams. There was a significant discrepancy between the imaging modalities in the identification of calcifications (P < .001), especially for radicular calcifications of maxillary teeth (DPR = 55.2%; CBCT = 30.9%). In the case of coronal calcifications, there was a greater discrepancy between CBCT and DPR in the mandibular teeth (10.7%) than in the maxillary teeth (7.7%). Overall, DPR presents higher sensitivity (0.855) than specificity (0.483) for pulp calcifications detection. CONCLUSION: DPR considerably overestimates pulp calcifications in posterior teeth, as compared to CBCT. A higher prevalence of pulp calcifications is related to decayed and restored teeth.

Assessment of the root filling volume in C-shaped root canal on cone-beam CT and micro-CT in relation to nano-CT.

AIM: To assess the observed volume of filled C-shaped root canals from different CBCT and micro-CT having nano-CT as a reference. MATERIALS AND METHODS: Twelve extracted mandibular molars with C-shaped root canals were endodontically treated using Reciproc Blue R25 (VDW GMBH, Munich, Germany) in a reciprocating system and filled with gutta-percha (Dentsply Maillefer) and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). CBCT scans were performed using 3 units-3D Accuitomo 170 (J. Morita, Kyoto, Japan), ProMax 3D Max (Planmeca, Helsinki, Finland), and NewTom VGi EVO (Cefla QR, Verona, Italy)-at two resolution modes: standard and high. Micro-CT and nano-CT scans were also obtained. The volume of all filled C-shaped root canals was obtained using CTAn software (Bruker, Kontich, Belgium), and the blooming artifact, in relation to nano-CT volume, was calculated. The data were evaluated by the Bland-Altman plots and ANOVA two-way for repeated measures (α = 0.05). RESULTS: All CBCT units and micro-CT showed significantly larger observed volume of root canal filling when compared to nano-CT. The blooming artifact of root canal filling in standard resolution was significantly larger than that in high resolution (p < 0.05) in all CBCT units. CONCLUSIONS: Endodontic filling material with AH Plus sealer causes blooming artifacts in CBCT units and micro-CT. CLINICAL RELEVANCE: Considering the anatomical complexity of C-shaped root canals and the challenges associated with endodontic treatment, CBCT is frequently recommended for follow-up evaluations. However, the presence of endodontic filling material can result in blooming artifacts that may potentially impact the accurate diagnosis of endodontic complications.

Influence of bioceramic cones on the quality of root canal filling relative to bond strength and adaptation of the adhesive interface.

AIM: To evaluate the bond strength (BS) and analysis of the adhesive interface in root canals filled with bioceramic gutta percha sealers and cones. MATERIAL AND METHODS: Ninety-six maxillary canines were divided into eight groups according to the endodontic sealer (AH Plus, AH Plus Bioceramic, Bio-C Sealer or Bio-C Sealer Ion+ and gutta percha cones (conventional or bioceramic) tested. They were analyzed using the BS test, failure pattern, analysis of the adhesive interface by scanning electron microscopy and confocal laser scanning microscopy. The BS data were compared between groups using the analysis of variance test with the Turkey post-test. The chi-square test was used to assess the type of failure and the non-parametric Mann-Whitney and Kruse-Wallis tests (P < 0.05). RESULTS: Analysis of variance showed higher BS values for the groups of bioceramic gutta percha cones in Bio-C Sealer Ion+ (8.38 ± 4.27), AH Plus Bioceramic (6.19 ± 3.28), Bio-C Sealer (5.70 ± 3.18), AH Plus (4.61 ± 2.11) and for conventional gutta percha cones in AH Plus sealers (4.26 ± 2.35), Bio-C Sealer Ion + (3.63 ± 2.29), Bio-C Sealer (2.94 ± 2.32) and AH Plus Bioceramic (1.19 ± 0.89) (P < 0.05). Relative to the type of failure and adaptation of the types of filling material, a higher percentage of mixed failures was observed (gaps between 1 µm-10 µm) for the group with bioceramic gutta percha cones (P < 0.001). CONCLUSION: The bond between sealers and bioceramic gutta percha cones showed higher bond strength values and greater penetration into the dentin tubules. CLINICAL RELEVANCE: The filling the root canal system with bioceramic sealers should be associated with bioceramic gutta percha cones.

Impact of several NiTi-thermally treated instrumentation systems on biomechanical preparation of curved root canals in extracted mandibular molars.

AIM: To evaluate the shaping ability of several heat-treated nickel-titanium systems used to prepare root canals with moderate and severe curvature, in extracted mandibular molars, by micro-computed tomography, considering their variation in kinematics and design. METHODOLOGY: Curved-mesial roots of mandibular molars were randomly selected and assigned into 4 balanced experimental groups (n = 10), established by determining homogeneous 3D parameters of volume and surface area: R-Motion (RM) size 30, 0.04 taper (RM; FKG Dentaire), Reciproc Blue (RCB) size 25, 0.08 taper (RCB; VDW GmbH), HyFlex CM (HFX) size 30, 0.04 taper (HFX; Coltène Whaledent) and XP-endo Shaper size (XPS) 30, 0.01 taper (XPS; FKG Dentaire). The volume of irrigation was established at 10 ml of 2.5% NaOCl. Throughout the entire root canal preparation procedures, the samples were fixed in a vice submerged in a container with water monitored at 37°C. Dimensional cross-sectional measures of area, perimeter, roundness, major/minor diameters and 3-dimensional (volume, surface area, structure model index - SMI) parameters as well as the smallest dentine thickness along the cervical and middle root thirds were evaluated by micro-CT. Data were analysed using analysis of variance and post hoc Tukey tests (α = 5%). RESULTS: Reciproc Blue and XPS had significantly greater mean increases in cross-sectional area measurements, only in the middle third, when compared with RM and HFX (p < .05). RM, RCB and XPS had a similar increase in measurements of length and width of perimeter (p > .05), and HFX had significantly lower mean increases in perimeter values only when compared with XPS (p < .05). RCB and XPS had significantly greater mean increases in volume when compared with RM and HFX (p < .05). RM had a significantly lower difference in SMI after preparation, compared with RCB, HFX and XPS (p < .05). The smallest dentine thickness was observed after the use of RCB (p < .05), in the danger and safety zones. CONCLUSIONS: XP-endo Shaper and RM had a shaping ability similar to that of instruments with larger tapers, achieved with less dentine removal in danger and safe zones in curved-mesial canals of extracted molar teeth treated on a laboratory benchtop.

Is the quality of root canal filling obtained by cone-beam computed tomography associated with periapical lesions? A systematic review and meta-analysis.

AIM: To evaluate the influence of root canal filling quality on periapical lesion status using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: The bibliographic search was conducted in electronic databases of PubMed, Embase, Scopus, and Web of Science without restrictions related to the year of publication and language. Inclusion criteria were prospective or retrospective cohort studies that followed periapical pathosis for, at least, 1 year. Three reviewers independently evaluated the eligibility for inclusion, extracted data, and assessed the risk of bias. The quality of the studies was based on the Newcastle-Ottawa Scale. This meta-analysis was performed to evaluate the quality of treatment by the homogeneity and apical extension of the filling. RESULTS: Of the 1179 studies initially recovered, six cohort studies were included, out of which four were considered with a low risk of bias. The results showed that the absence of gaps in the filling reduced the chance of unhealed periapical lesions by 2.39 times (RR = 2.39; 95% CI: 1.62-3.53; p < 0.00001; I2 = 55%). An apical filling extension of 0-2 mm below the apex also contributed significantly to the absence of unhealed periapical lesions (RR = 1.49; 95% CI: 1.15-1.94; p = 0.003; I2 = 2%). CONCLUSION: The homogeneity and apical extension of the filling influenced the presence of unhealed periapical lesions in endodontically treated teeth evaluated using CBCT. CLINICAL RELEVANCE: Apical extension of the filling ranging between 0 and 2 mm short of the apical foramen and the homogeneity of the filling without gaps are directly related to the success rate of root canal treatment.

Effect of a chitosan final rinse on the bond strength of root canal fillings.

This study was designed to evaluate the effect of a final rinse with 0.2% chitosan solution on the adhesion in roots filled with gutta percha and an epoxy resin based sealer. Thirty extracted human maxillary canines selected to ensure specimen standardization were used in the study. After the coronal portion of each tooth was removed, the roots were instrumented and irrigated with 1% sodium hypochlorite (NaOCl). Roots were distributed into 3 groups according to the final rinsing solution (n = 10): 0.2% chitosan, 17% ethylenediaminetetraacetic acid (EDTA), or 1% NaOCl. The canals were irrigated with 5 mL of each solution for 5 minutes and then filled with gutta percha cones and the resin based sealer. Ten roots in each group were prepared, sectioned, and submitted to push-out testing. Data were analyzed with analysis of variance and Tukey test (P < 0.05). In the push-out test, final irrigation with chitosan (mean, 0.37 [SD, 0.12] MPa) or EDTA (0.38 [0.11] MPa) resulted in significantly greater bond strength of the sealer to the root canal (P < 0.05) than did irrigation with 1% NaOCl (0.13 [0.04] MPa). The cervical third had greater bond strength than the other thirds (P < 0.05). Adhesive failure was the most frequent type in all groups. A final rinse with 0.2% chitosan or 17% EDTA resulted in greater bond strength of root fillings to the root canal than did 1% NaOCl.

Optical coherence tomography and gray scale digital analysis as noninvasive techniques for evaluating molar-incisor hypomineralization severity: A comparative study with microcomputed tomography.

Molar-incisor hypomineralization (MIH) is a qualitative defect of dental enamel characterized by demarcated opacities present in permanent first molars and other teeth. It is considered a major clinical challenge in dentistry because it makes affected teeth more susceptible to fractures and dental caries. Its diagnosis is mainly clinical and there are few technological resources that allow for a more accurate diagnosis, especially with respect to the depth of the defect in the dental enamel. In this context, optical coherence tomography (OCT), which is routinely used in ophthalmology, can produce images of the depth of the dental enamel, making it a promising method. In this study, 33 teeth with different MIH severities were evaluated using OCT and microcomputed tomography (microCT). Semi-quantitative methods of grayscale pattern analysis were used to compare images obtained from different severities of MIH with the mineral density obtained through microCT. MicroCT evaluation revealed that hypomineralized enamel had a significantly lower mineral density than intact enamel. However, this difference was not observed between the mild and severe MIH lesions. In the OCT evaluation, significant differences were observed between the intact and hypomineralized enamel, and the gray value comparison provided a method for quantitative differentiation between the two. This study suggests that OCT could be a useful adjunct to traditional diagnostic methods for MIH, offering a noninvasive approach to evaluate enamel defects. RESEARCH HIGHLIGHTS: Combining optical coherence tomography with grayscale digital analysis shows potential as a promising method for diagnosing molar-incisor hypomineralization and assessing its level of severity.

Physicochemical properties of calcium silicate cement based endodontic sealers.

AIM: To mensure the physicochemical properties of three ceramic cement endodontic sealers AH Plus Bioceramic, Bio-C Sealer and Bio-C Sealer Ion+ with an epoxy resin sealer, AH Plus. MATERIAL AND METHODS: These properties were measured: hardening time (HT), dimensional change (DC), solubility (SL), flow (FL) and radiopacity (RD). The distilled water obtained from the SL test was analyzed with atomic absorption spectrometry. A sample calculation was made considering n = 5 repetitions for each experimental sealer evaluated. Statistical analysis was performed using one-way ANOVA and post hoc Tukey tests (p < 0.05). RESULTS: For the HT, AH Plus (484 ± 2.76 min) and AH Plus Bioceramic (424 ± 1.23 min) set more slowly than of Bio-C Sealer (370 ± 4.50 min) and Bio-C Sealer Ion+ (380 ± 1.42 min) (p < 0.05). AH Plus Bioceramic (12.56 ± 2.71 %) was more soluble than Bio-C Sealer (6.69 ± 1.67 %), Bio-C Sealer Ion+ (5.67 ± 2.16 %) and AH Plus (0.15 ± 0.01 %) (p < 0.05). AH Plus (0.03 ± 0.01 %) had slight expansion while the cement-based sealers had shrinkage: AH Plus Bioceramic (-1.60 ± 0.63 %) and Bio-C Sealer (-1.38 ± 0.69 %), Bio-C Sealer Ion+ (-5.19 ± 1.23 %) (p < 0.05). Bio-C Sealer Ion+ (59.80 ± 0.86 mm) and Bio-C Sealer (58.60 ± 0.98 mm) had the highest flow compared with AH Plus (56.90 ± 0.56 mm) and AH Plus Bioceramic (49.50 ± 0.63 mm) (p < 0.05). AH Plus (9.17 ± 0.06 mmAl) and AH Plus Bioceramic (8.27 ± 0.84 mmAl) showed radiopacity values when compared with those of Bio-C Sealer (4.90 ± 0.08 mmAl) and Bio-C Sealer Ion+ (4.14 ± 0.05 mmAl) (p > 0.05). CONCLUSION: Ion release is inhered to these cement-based sealers and this result in calcium ion release.

Accuracy of Magnetic Resonance Imaging in Clinical Endodontic Applications: A Systematic Review.

INTRODUCTION: The development of dedicated coils and new magnetic resonance imaging (MRI) sequences has led to an increase in image resolution and a reduction in artifacts. Consequently, numerous studies have demonstrated the utility of MRI as a nonionizing alternative to cone-beam computed tomographic imaging. The aim of this systematic review was to evaluate the accuracy of MRI in clinical applications in endodontics. METHODS: A literature search was conducted using PubMed, Embase, Scopus, and Web of Science. The inclusion criteria encompassed studies evaluating MRI applications in endodontics, covering tooth and root canal anatomy, root canal working length, pulp vitality and regeneration, the effect of caries on dental pulp, guided endodontics, periapical lesions, and root cracks/fractures. The selected studies examined both ex vivo and in vivo human teeth using clinical MRI units. Two researchers independently screened the studies, applied the eligibility criteria, and assessed the potential risk of bias using the revised QUADAS-2 tool (Bristol Medical School, University of Bristol, UK). RESULTS: A total of 18 studies were included in this systematic review, demonstrating that the use of MRI has a high diagnostic value in endodontics. In the evaluation of tooth and root canal anatomy, pulp vitality and regeneration, the effect of caries on dental pulp, periapical lesions, and root cracks/fractures, MRI's accuracy is comparable to or even higher than reference standards such as cone-beam computed tomographic imaging, micro-computed tomographic imaging, and histology. CONCLUSIONS: MRI has high potential accuracy for diagnosing various clinical endodontic tasks, except for root canal length, size of caries, and periapical lesion dimensions, which are overestimated in MRI.

Could Low-dose Cone-beam CT be Used for Endodontic Intraoperative Diagnosis?

INTRODUCTION: Cone-beam computed tomography (CBCT) allows three-dimensional evaluation and has high diagnostic accuracy of endodontic conditions. Considering that the most indicated protocol for endodontics should have smaller field-of-view and higher spatial resolution, a higher radiation dose may be associated. Thus, this study evaluated the accuracy of an optimized CBCT protocol for the detection of intraoperative endodontic complications. METHODS: An image phantom was custom-made with a human mandible covered with Mix-D and forty mandibular first molars. The teeth were subdivided into 4 groups of endodontic complications which were simulated. All teeth were individually inserted into the left second molar socket of the phantom and CBCT images were acquired with OP 300 unit adjusted to a field-of-view of 6 × 4 cm, 90kVp, and 2 dose protocols: low and high. Furthermore, a titanium implant, a tooth with endodontic treatment, and a cobalt-chromium post were inserted into the empty sockets adjacent to the teeth of interest and additional images were acquired. Four endodontists evaluated the images and indicated the presence of endodontic complications on a 5-point scale. Sensitivity, specificity, and area under the receiver operating characteristic curve were obtained. The different groups were compared by ANOVA and Tukey tests (α = 0.05). RESULTS: In most conditions, irrespective of the presence of metallic materials, the values of accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve did not differ significantly (P > .05) between the dose protocols. CONCLUSIONS: Optimized CBCT protocols should be considered for the detection of intraoperative endodontic Diagnostic complications.

Evaluation of rotary instruments with whipping motion in the biomechanical preparation of large root canals of young permanent teeth.

Shaping ability evaluation of taper ./01 instruments in large root canals, by microcomputed tomography (micro-CT) and scanning electron microscopy (SEM). Maxillary central incisors with large diameter root canals were divided into two groups (n = 10): XP-Endo Shaper (FKG-Dentaire, Switzerland) and manual instrumentation (FKG-Dentaire). Two- and three-dimensional parameters from cervical to apical root thirds were evaluated by micro-CT. Apical stop was evaluated by SEM images. Data were analysed by ANOVA and Tukey tests (α = 5%). XP-Endo Shaper allowed a regular biomechanical preparation with less dentinal wear compared with manual instrumentation, which showed excessive wear of the thin root canal walls (p < 0.05). Roundness and SMI showed similarity between both protocols (p > 0.05). XP-Endo Shaper SEM showed a regular and well-defined shape of the apical foramen suggesting the formation of the apical stop. Reduced diameter and taper instruments promoted a conservative wear and a well-defined apical stop formation in large root canals.

Evaluation of 2- and 3-dimensional anatomic parameters of C-shaped root canals with cone beam computed tomography, microcomputed tomography, and nanocomputed tomography.

OBJECTIVE: The objective of this study was to evaluate 2-dimensional (2D) and 3D morphometric parameters of C-shaped root canals on cone beam computed tomography (CBCT) and microcomputed tomography (microCT) images using nanocomputed tomography (nanoCT) as the reference standard. STUDY DESIGN: Sixty mandibular molars with C-shaped canals were individually scanned using nanoCT and microCT. Cone beam computed tomography acquisitions were then performed with 4 CBCT systems, using high and standard resolutions. The 2D parameters of roundness and major and minor diameters were obtained in the cross sections of the root canals at 1, 2, and 3 mm from the root apex. The 3D parameters of surface area, volume, and structure model index were measured considering the entire extension of the root canals. Absolute error (AE) in measurement was calculated against the nanoCT values. Data were statistically analyzed with the Shapiro-Wilk test and analysis of variance (α = 0.05). RESULTS: No significant differences in AE were discovered for the 2D parameters among microCT and the CBCT scans. The AE values for the 3D parameters of volume and surface area were significantly smaller in microCT compared to all CBCT units (P < .05). Significantly lower AE values for surface area were observed in high resolution compared to standard resolution for all CBCT units (P < .05). Structure model index did not differ significantly among microCT and all CBCT protocols. CONCLUSIONS: Cone beam computed tomography images showed accuracy for evaluating 2D parameters and over- and underestimation for 3D parameters.

Canal Drying Protocols to Use with Calcium Silicate-based Sealer: Effect on Bond Strength and Adhesive Interface.

INTRODUCTION: The aim of this study was to evaluate the influence on bond strength and interface quality of different canal drying protocols in roots filled with Bio-C Sealer (BCS; Angelus, Londrina, Paraná, Brazil). METHODS: Ninety-six roots of upper canines were prepared with an R50 file (Reciproc; VDW GmbH, Munich, Germany) and irrigated with 2.5% sodium hypochlorite and 17% EDTA under ultrasonic agitation. Roots were divided according to the drying protocol as follows: dry, the White Mac tip (Ultradent, Indaiatuba, SP, Brazil) for 5 seconds followed by aspiration with a capillary tip for 5 seconds and paper points; slightly moist, the White Mac tip followed by capillary aspiration without paper points; wet, the White Mac tip followed by a single paper point. The roots were filled with BCS or AH Plus (AHP; Dentsply Maillefer, Ballaigues, Switzerland) (n = 16) and sectioned for the push-out test after 3 months. Failure modes were assessed, and the interface morphology was analyzed under scanning electron microscopy. After 6 months, the other half of the roots were evaluated. Data were analyzed by analysis of variance/Tukey test at 5%. The chi-square test was used in the failure analysis and the Kruskal-Wallis/Dwass-Steel-Critchlow-Fligner for interface analysis. RESULTS: The AHP-filled roots had the highest bond strength when the canal was dried (P < .05). No difference was found for periods (P > .05). For BCS, the highest bond strength was found in the slightly moist canals (P < .05). A predominance of adhesive failures was observed. The dried canals filled with AHP had the highest percentage of good adaptation, whereas BCS had no difference. CONCLUSIONS: The best drying protocol for AHP is using the White Mac tip followed by capillary tip aspiration and paper points until complete dryness, and for BCS, it is using the White Mac tip followed by capillary aspiration without paper points.

Evaluation of the push-out bond strength of an adjustable fiberglass post system to an endodontically treated oval root canal.

To evaluate the push-out bond strength of the adjustable fiberglass post system to dentin. Twenty maxillary canine roots were endodontically treated and divided into two groups (n=10): conventional fiberglass posts (CFPs) and with single adjustable post (SAP) system. Two slices of each third were subjected to the push-out and failure pattern test and the most apical slice was subjected to analysis of the adhesive interface by scanning electron microscopy (SEM). Data were analyzed by the three-way analysis of variance, Tukey, and Friedman tests, and linear regression (α=0.05). The results showed higher push-out bond strength in the initial time interval for SAP (10.3±5.3, p<0.01). After 6 months, there was reduction in push-out bond strength for both (p<0.001). A higher percentage of adhesive and cohesive failures to dentin. After 6 months areas of maladaptation were noted (p=0.000). The SAP is completed to the promissory root canal in relation to alternative CFP.

Influence of bioceramic intracanal medication on the bond strength of bioceramic root canal sealer.

To investigate the influence of the remaining volume of a new intracanal medication based on bioceramic compounds on the bond strength (BS) and formation of an adhesive interface between calcium silicate-based and epoxy resin-based root canal sealers. For this purpose, the specimens were distributed according to the intracanal medication (n = 26): Bio-C Temp (BCT) and Ultracal XS (UXS). The roots were scanned in microCT, and after 7 days, the medication was removed. Then a new scan was performed to evaluate the volume of medication remaining. Subsequently, 40 specimens were redistributed into 2 subgroups (n = 10) and filled according to the sealer used: AH Plus (AHP) and Bio-C Sealer (BCS), to assess the bond strength by using the push-out test, and the adhesive interface by confocal laser fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The t test showed a smaller remainder of BCT (1.77 ± 0.86) compared with UXS (10.47 ± 5.78), irrespective of the root third evaluated. The BS showed that teeth with BCT + BCS had higher bond strength values (3.70 ± 1.22) when compared to the other groups: BCT + AHP (2.15 ± 1.07), UXS + BCS (3.18 ± 1.09) and UXS + AHP (2.11 ± 1.02) (p<0.001). The cervical third had higher BS when compared with the middle and apical thirds (p < 0.001), and higher number of adhesive failures. The adhesive interface in SEM and CLSM images showed better adaptation for the association between BCT + BCS. Intracanal medication and silicate-based endodontic sealer appeared to interact chemically by forming a biomineralizing layer, allowing for an increase in the bond strength and forming an adhesive interface between the materials, with no or less gap formation.

Prevalence and morphological analysis of dens invaginatus in anterior teeth using cone beam computed tomography: A systematic review and meta-analysis.

OBJECTIVES: To evaluate the prevalence and morphological characteristics of DI using CBCT. METHODS: A literature search was performed in PubMed, Embase, Scopus, and Web of Science. Inclusion criteria were randomized clinical trials, cross-sectional studies, and prospective and retrospective cohort studies evaluating the morphological characteristics of DI in anterior teeth using CBCT. Three reviewer authors independently screened the studies, applied the eligibility criteria, assessed the risk of bias, and extracted until September (2022). The risk of bias was evaluated using the Joanna Briggs Institute criteria. Meta-analyses of proportions were used for estimate the prevalence DI according to factors at participant and tooth levels. RESULTS: Six studies were included in the meta-analysis. Among 7373 individuals, a prevalence of 7.45 % of DI was observed (n = 258; τ2 = 0.0096; CI of 4.51-11.3; p < 0.05), with no significant influence of sex. Regarding laterality, unilateral DI showed higher mean prevalence (4.30 %; CI of 2.03-7.33). Among the 382 anterior teeth with DI (0.72 %), the most affected tooth was the upper lateral incisor (5.12 %; n = 329; CI of 2.35-8.86; p < 0.001), type I was the most prevalent (0.59 %; CI of 0.24-1.08) and the presence of open apex and periradicular pathology ranged from 4.3 % to 22.72 % and 3.5-77.92 %, respectively. CONCLUSIONS: The prevalence of individuals with dens invaginatus was 7.45 %, the most affect tooth was the upper lateral incisor with a prevalence of 5.12 % unilaterally and type I was the most prevalent morphology.

Impact of access cavities on root canal preparation, restorative protocol quality, and fracture resistance of teeth.

The survival of endodontically treated teeth depends on the remaining tooth structure. The aim of this study was to evaluate the impact of different access cavities on root canal preparation, restorative protocol, and fracture resistance of endodontically treated teeth. Fifty-six mandibular molars were divided into control (n=8) and experimental (n=16) groups according to access cavity: Traditional, Conservative, and Truss; and redistributed (n=8) according to instrumentation protocols: Reciproc Blue and R-motion. After, teeth were scanned in micro-CT and then filled and redistributed according to composite resin restoration (n=8): Filtek One BulkFill and Filtek Z350. A new micro-CT scan was performed to analyze the restorative material. Then, samples were submitted to fracture resistance testing and the failure pattern was determined. Data were analyzed using paired T-test, ANOVA, Tukey, and chi-square tests (α=0.05). In Truss, R-Motion promoted less transportation in different thirds of root canals. Higher percentages of voids (5.05%) and filling material (11.7%) were observed in Truss. Fracture resistance values were higher for the control group, followed by Truss, Conservative, and Traditional. The predominant failure pattern was type-II. In Truss, reciprocating instruments with smaller taper showed less canal transportation. Also, Truss provided higher values of fracture resistance, although it presented a higher percentage of voids and remaining filling material. Thus, in Truss, reciprocating files with smaller taper showed less canal transportation, and these cavities provided higher values of fracture resistance, although it presented a higher percentage of voids and remaining filling material.

Influence of different calcium hydroxide removal protocols on the bond strength of epoxy resin-based sealer in long oval root canals.

This study evaluated the effect of different protocols for Ca(OH)2 removal on the bond strength (BS) of epoxy resin-based sealer in long oval root canals. Forty-eight mandibular incisors with long oval root canals were selected by CBCT. Biomechanical preparation was performed, the samples were filled with Ca(OH)2 paste and distributed in four groups (n = 12): G-without Ca(OH)2 paste (C); G2-syringe/needle (SN); G3-SN + XP-Endo® Finisher (XPF); G4-SN + passive ultrasonic irrigation (PUI). After 7 days, Ca(OH)2 was removed and teeth were filled using AHPlus and guttapercha. In four samples from each group, the sealer was manipulated with 0.1% rhodamine to assess sealer penetration by fluorescent laser confocal microscopy (FLCM). Samples were sectioned in slices for BS, scanning electron microscopy, and FLCM analysis. The BS data were analyzed by ANOVA and Tukey tests (α = 0.05). The lowest BS values were found for the SN group (12.89 ± 4.36) compared to C (35.55 ± 10.05), while PUI group presented intermediate values (28.57 ± 9.35) and the XPF group (31.34 ± 9.8) showed values that were sometimes similar to C group and sometimes similar to PUI group (p > .05). The analysis of the adhesive interface showed evident gaps, with the presence of residues between the dentin and the filling material for the SN group, and for C, XPF and PUI groups juxtaposed adhesive interface. FLCM images showed sealer penetration in the dentinal tubules along the entire perimeter for C, XPF, and PUI groups. Ca(OH)2 removal with XPF and PUI from long oval root canals resulted in higher bond strength values compared to SN, besides better sealer penetration on dentinal tubules and juxtaposed adhesive interface.