Micro-CT evaluation of root filling quality in oval-shaped canals

Effect of the filling technique on the filling removal from oval-shaped canals

OBJECTIVES

This ex vivo study aimed to evaluate the influence of different filling techniques on the filling removal from oval root canals filled with bioceramic sealer.

METHODS

Thirty-six mandibular incisors with single oval canals were filled with bioceramic sealer following the techniques (n = 12): single-cone, modified McSpadden, or continuous wave of condensation, and scanned by micro-computed tomography (micro-CT). The filling was removed using the Clearsonic ultrasound tip and Reciproc system up to the R40 instrument, and the working time was recorded. The teeth were scanned again by micro-CT. Percentage of remnant volume (mm³) of the filling material, dentin thickness, and root canal transportation were measured. The data was analyzed using parametric and non-parametric tests with a significance level of 5%.

RESULTS

It took more time to remove the filling material using the continuous wave of condensation technique (p < 0.05), followed by the modified McSpadden and single-cone techniques. There was no difference (p > 0.05) when comparing the percentage of remaining filling material among the three groups, nor did it among the segments of each tooth. There was also no difference in the analysis of dentin thickness and transportation when comparing the groups (p > 0.05).

CONCLUSIONS

The filling technique did not influence the amount of remaining filling material, dentin thickness, and transportation. The working time was longer with thermoplastic filling techniques.

CLINICAL RELEVANCE

Endodontic retreatment in teeth filled with bioceramic sealers increases with their use. Several techniques are used to fill the root canals, thus, it is important to know whether the filling technique influences the non-surgical endodontic retreatment.

Effectiveness of Sectioning Method and Filling Materials on Roughness and Cell Attachments in Root Resection Procedure

OBJECTIVES

 The purpose of the present study was to investigate the created roughness and cell attachment of intact teeth (C), obturated teeth with bioceramic (BR), or epoxy resin (AH) after root resection using piezoelectric ultrasonic and carbide bur.

MATERIALS AND METHODS

 Three groups of first mandibular premolars were used in the present study: control group (without any preparation or obturation) (C); second group was obturated with an epoxy resin sealer (AH, AH Plus Jet); and finally, the third one was obturated with a bioceramic sealer (BR, BioRoot RCS). All teeth were incubated for 4 months at 37°C. After that, the samples were sectioned using tungsten carbide bur or piezoelectric ultrasonic. Roughness and then cell attachment of periodontal ligament cells on the sectioned surfaces were investigated by profilometer and confocal microscope, respectively.

STATISTICAL ANALYSIS

 Data were statistically analyzed using one-way analysis of variance.

RESULTS

 After root resection, no significant difference was found between the roughness among the three groups sectioned using the piezoelectric technique (p > 0.05). In contrast, concerning the sectioned samples by burs, C demonstrated a rougher surface compared with BR (p < 0.05). There was a significant higher cell attachment in BR compared with AH in the piezoelectric groups (p = 0.047), while no statistically significant difference was found between the groups sectioned with bur (p > 0.05).

CONCLUSION

 Dentists are now focused on the use of calcium silicate-based sealers due to their bioactivity. The present study advises dentists to use bioceramic sealer which could improve the dentin characteristics which ameliorate the cell attachment.

Exploring access cavity through non-carious cervical lesions: Impacts on instrumentation, obturation, and fracture resistance in mandibular incisors

AIM

To compare the effects of Cervical Access Cavity (CervAC) and Traditional Access Cavity (TradAC) on root canal preparation, root canal filling, and fracture resistance in mandibular incisors.

METHODOLOGY

Twenty recently extracted and intact mandibular incisors were initially scanned using a micro-CT device. The specimens were anatomically matched to create two groups (n = 10). A wedge-shaped non-carious cervical lesion (NCCL) was created on the buccal aspect of all teeth using a double-faced segmented diamond disc. In group 1, a TradAC was prepared, whilst in group 2, access was created through the simulated NCCL using a round diamond bur 1012. After root canal preparation with Rotate instruments sizes 15/0.04, 20/0.04, and 25/0.04, the teeth were scanned again and evaluated for root canal volume and surface area, static voxels, volume of removed dental tissue, and dentine thickness. After that, the root canals were filled using the single-cone technique, teeth were restored with composite resin, and subsequently rescanned to calculate the volume of filling materials and voids. Then, the restored teeth were subjected to fracture resistance tests using a universal testing machine. Statistical comparisons between groups were performed with the Mann-Whitney test or the Student's t-test, with a statistical significance level of 5%.

RESULTS

Statistical comparisons indicated no significant differences between groups in terms of root canal volume, surface area, static voxels, removed root dentine, root canal filling volume, percentage of voids, or fracture resistance load (p > .05). Conversely, teeth prepared with TradAC showed a significantly higher percentage of dental tissue removed from the crown (p = .001) and a greater volume of filling material remnants in the pulp chamber (p < .001) compared to the CervAC group. A significantly lower percentage reduction in dentine thickness was observed only on the mesial aspect of root at Level 1 in TradAC group (p = .008).

CONCLUSIONS

CervAC can be considered a viable alternative approach in the presence of NCCL in mandibular incisors.

Reducing apical voids for intra-canal sealer injection using a modified passive deflation needle

The aim of the study was to evaluate the ability of a modified passive deflation needle to reduce the apical voids during the intra-canal iRoot SP sealer injection. A modified passive deflation injection needle was designed. Forty 20°-curved and twenty S-shaped single-canal resin block models were allocated into six groups. Each group was mechanically prepared to #25/04 or #25/06 file; then the root canals were injected with iRoot SP sealer using a modified needle or a normal plastic needle. Radiographs were taken to measure the length of apical void in each specimen. Similarly, twenty single-canal extracted premolars were collected and randomly divided into four groups. Each group was prepared to #25/04 or #25/06 file; then the root canals were injected with iRoot SP sealer using a modified needle or a normal plastic needle. Roots were then scanned using micro-computed tomography (micro-CT), and the volume of voids in root canals was analyzed and compared among groups. Statistical analysis demonstrated that the length and the volumetric percentage of voids were much lower in the modified needle group in both resin block root canal models and extract teeth than the normal plastic needle group (P < 0.05). The modified passive deflation needle can efficiently reduce apical voids during the intra-canal iRoot SP sealer injection.

Solcia AB, Guerreiro-Tanomaru JM, Tanomaru-Filho M, Faria G. Evaluation of Solubility, and Volumetric and Morphological Alterations of Bioceramic Filling Material for Primary Teeth: A New Methodological Approach

Objective

To evaluate the solubility and the volumetric and morphological alterations of bioceramic filling material (Bio-CP) for primary teeth.

Materials and Methods

Bio-CP, Calen thickened with zinc oxide (Calen-ZO), and with zinc oxide eugenol (ZOE) were placed in 1- or 2-mm-diameter polyethylene tubes and immersed in water or phosphate-buffered saline (PBS) for 30 days. The solubility (mass loss) was assessed using methodology modified from ISO 6876. Filling capacity, volumetric changes, and presence of voids were assessed by microcomputed tomography (micro-CT). The surface distribution of the chemical elements and the crystalline phases was evaluated by energy scattering X-ray scanning electron microscopy (SEM-EDX) and X-ray diffraction (XRD) to detect hydroxyapatite precipitate and components. The Shapiro-Wilk, Kruskal-Wallis, and Dunn's or two-way ANOVA and Tukey post hoc test were used (α = 0.05).

Results

The solubility was ZOE > Calen-ZO = Bio-CP. Calen-ZO and Bio-CP were more soluble in water than in PBS. All the materials showed greater solubility in 2-mm tube diameter in both PBS and distilled water, except for Bio-CP in distilled water, which showed no difference between both tube diameters (1 and 2 mm). Only Calen-ZO and ZOE were analyzed by micro-CT, because Bio-CP separated into two phases during scanning. Calen-ZO had greater volumetric loss and presence of voids than ZOE in water, but there was no difference in PBS. The hydroxyapatite precipitate on the surface of Bio-CP and Calen-ZO was detected after immersion in PBS.

Conclusion

Although Bio-CP had acceptable solubility and filling capacity, its composition did not allow a proper volumetric and void assessment. From a clinical perspective, Bio-CP has the potential to become a suitable material for root canal filling in primary teeth. Nonetheless, its composition must first be revised to achieve better chemical stability prior to its recommendation.

Hydraulic (Single Cone) Versus Thermogenic (Warm Vertical Compaction) Obturation Techniques: A Systematic Review

Root canal treatment (RCT) involves cleaning and shaping of the root canal system before filling the canals with obturating materials, often gutta-percha (GP). The two primary obturation techniques are the thermogenic (warm vertical compaction, WVC) and hydraulic (single cone, SC) techniques. The objective of this study is to compare the clinical results and effectiveness of thermogenic and hydraulic obturation procedures in endodontic therapy to provide clinicians with evidence-based recommendations. Search strategies were conducted on February 01, 2024 and involved the databases Web of Science, PUBMED, Google Scholar, Scopus, Medline, Embase, NCBI, and Cochrane Library. The current systematic review included systematic reviews; meta-analyses; cohort studies; randomized controlled trial (RCT) studies; studies involving the comparison between single cone and warm compaction techniques; studies involving outcomes that include advantages, disadvantages, and complications associated with single cone or warm compaction techniques; and studies published within the last seven years. The selected studies were restricted to those with insufficient data, review articles without authentic references, publications in a language other than English, animal studies, and studies not involving SC or WVC. Out of 2300 studies registered, only 12 studies were included in the review. Both WVC and SC techniques showed satisfactory root canal fillings. However, five studies showed differences in the filling quality, four studies assessed the sealing ability and the dentinal tubule penetration of sealers, one study compared dentinal cracks, one study evaluated the amount of debris excluded apically, and one study compared the post-operative pain while using both techniques. The WVC and SC obturation techniques offer advantages and disadvantages in endodontic treatment. SC obturation is a simple and efficient procedure that is particularly suitable for situations with uncomplicated canal structures. The WVC obturation approach provides superior flexibility and sealing capability, especially in the complex root canal system. When choosing the method of treatment, it is important to take into account the patient's preferences, the clinician's experience, and unique considerations related to the situation. This systematic review highlights the important recommendations to healthcare professionals in selecting the most suitable obturation procedure based on the specific requirements of each clinical scenario. Research involving long-term follow-ups is required to get a better understanding of the outcomes of long-term goals. Clinical relevance: ability to educate clinicians regarding the best obturation technique between thermogenic and hydraulic. It directs the treatment decisions to maximize patient's comfort, minimize post-operative complications, and improve efficacy in endodontic practice.

Effects of Access Cavity Design and Placement Techniques on Mineral Trioxide Aggregate Obturation Quality in Simulated Immature Teeth: A Micro-Computed Tomography Study

Background and Objectives: In teeth with open apices, performing single session apexification is a challenging treatment due to the difficulty in handling mineral trioxide aggregate (MTA). Minimally invasive approaches in dentistry have also influenced the cavity designs in endodontics. Until now, different techniques have not been investigated in addition to manual condensation during the process of placing MTA in traditional (TradACs) or conservative (ConsACs) endodontic access cavities. The aim of this in vitro study was to compare and evaluate the obturation quality of MTA apical plugs placed with different techniques in TradACs or ConsACs. Materials and Methods: Sixty upper central teeth were divided into two main groups based on cavity design, and then each main group was further divided into three subgroups according to MTA placement techniques (n = 10): TradAC-manual, TradAC-manual + indirect ultrasonic activation, TradAC-manual + XP-endo Shaper (XPS), ConsAC-manual, ConsAC-manual + indirect ultrasonic activation, and ConsAC-manual + XPS. Subsequently, the porosity percentages in the MTA apical plug were analyzed using micro-computed tomography. The statistical analysis was performed using the Kruskal-Wallis H test and Mann-Whitney U test. Statistical significance was set at p < 0.05. Results: There were differences in volume of porosity percentages (%) according to cavity designs and MTA application techniques (p < 0.05). Except for the XPS group, more porosity was observed in ConsACs compared to TradACs. In TradACs, the significantly lowest open and total porosity was observed in the manual, ultrasonic, and XPS techniques, respectively. In ConsACs, the significantly lowest porosity was observed in the manual, XPS, and ultrasonic techniques, respectively (p < 0.05). Conclusions: In MTA obturation, cavity designs and application techniques had an impact on the MTA porosity. Creating an apical plug in ConsACs may result in more porosity compared to TradACs, especially when manual or indirect ultrasonic activation is preferred. Opting for the manual technique alone may be considered sufficient for controlling porosity for both TradACs and ConsACs.

Flatsonic Ultrasonic Tip Optimizes the Removal of Remaining Filling Material in Flattened Root Canals: A Micro-computed Tomographic Analysis

INTRODUCTION

The aim of this study was to evaluate the effectiveness of the XP-endo Finisher R (XPFR; FKG Dentaire, La Chaux-de-Fonds, Switzerland) or the Flatsonic ultrasonic tip (Helse Ultrasonic, Santa Rosa de Viterbo, SP, Brazil) in removing remaining filling material after the retreatment of flattened root canals using micro-computed tomographic imaging.

METHODS

Twenty-four flattened distal root canals of mandibular molars with a buccolingual diameter 4 or more times larger than the mesiodistal diameter were prepared with Reciproc Blue (RB) R40 (VDW GmbH, Munich, Germany) and filled using the Tagger hybrid technique. All canals were retreated with RB R40, and apical enlargement was performed with RB R50 (VDW GmbH). The specimens were randomly distributed into 2 groups: XPFR or Flatsonic (n = 12). The percentage of remaining filling material after retreatment and centralization ability was evaluated. Data were submitted to Mann-Whitney, Wilcoxon, and unpaired t tests (α = 5%).

RESULTS

Greater capacity to remove remaining filling material in the entire canal and the cervical and middle thirds was observed for the Flatsonic compared with the XPFR (P < .05). However, both supplementary cleaning techniques showed a similar percentage of residual filling material in the apical third (P > .05). No difference was observed in the centralization ability between the techniques (P > .05).

CONCLUSIONS

The Flatsonic promotes greater removal of remaining filling material than the XPFR in the retreatment of flattened root canals. However, both supplementary cleaning approaches were similar in the apical third. The XPFR and Flatsonic were able to maintain root canal centralization.

Micro-computed tomographic evaluation on the quality of single-cone obturation using a modified passive-deflation sealer injection needle: an in vitro study

OBJECTIVES

This study aimed to design a modified passive-deflation sealer injection needle and investigate its ability to improve obturation quality of single-cone technique through assessing the distribution of voids in root canals using micro-computed tomography (micro-CT).

MATERIALS AND METHODS

Forty-eight mandibular incisors were divided into eight groups (n = 6), according to the taper of root canal preparation (0.06 or 0.04), the needle used for sealer injection (modified or commercial iRoot SP injection needle), and the obturation method (iRoot SP sealer-only or single-cone obturation). After obturation, each specimen was scanned by micro-CT. The volumetric percentage and distribution of all voids were first analyzed and compared among groups, then the open and closed voids were separately analyzed and compared among single-cone obturation groups.

RESULTS

Compared to commercial needle groups, modified needle groups showed much less voids, especially in the apical root canal part (P < 0.05). Besides, the modified needle groups produced much less open voids than commercial needle groups despite the root canal taper (P < 0.05).

CONCLUSIONS

The modified passive deflation sealer injection needle could effectively improve the quality of single-cone obturation through reducing intra-canal voids, especially open voids throughout the root canal, thus might possibly be developed as an effective intra-canal sealer delivering instrument.

Comparative Evaluation of Volume and Homogeneity of Obturation with Four Different Obturation Systems Using Micro-Computed Tomography: An In vitro Study

Aim

To evaluate and compare volume and homogeneity of the three different root canal obturation systems.

Materials and Methods

Single-rooted premolar (n = 24) teeth samples were selected, and crowns were removed for standardization. Four groups are divided randomly as (n = 6), namely: For group I (single-cone gutta-percha obturation), group II (Beefill 2 in 1 obturation), group III (GuttaCore obturation), group IV (GuttaFlow bioseal obturation) and the root canal were subjected to prepare till X3 (protaper next) and subjected to micro-CT imaging. After completion of obturation, the image was taken by using micro-CT imaging. This is to evaluate the volume of filled obturation material in the canal space and the voided area sections, viz. the apical, middle, coronal, and third sections.

Results

Group III (GuttaCore obturation) showed the least significant mean of the difference in relation to the volume of the canal obturation (81.148). The least mean significant difference in area of voids in the canal region for apical (0.00133), middle (0.00233), and coronal thirds (0.00533). The most statistically significant difference is in the apical and middle thirds root canal space.

Conclusion

All the experimental groups showed significant differences in volume and voids in the obturation at three different levels, and the GuttaCore obturation systems occupied more of the volume with less voids in the prepared root canal space.

Effect of treatment variables on apical extrusion of debris during root canal retreatment: A systematic review and meta-analysis of laboratory studies

Background

This study aimed to systematically and comprehensively review the effect of various treatment variables on apically extruded debris (AED) during non-surgical root canal retreatment (NSRCRT).

Methods

The study protocol is shared in the Open Science Framework database (https://osf.io/kjtdg/?view_only=17060180705745ec9dae9a01614f3880). An electronic search was conducted up to July 2022 to reveal related studies. Two reviewers critically assessed the studies for eligibility against inclusion and exclusion criteria and data extraction. Quantitative data synthesis was performed, and the risk of bias in the studies was also evaluated.

Results

Forty-six studies were included in the systematic review and 14 in the meta-analysis. Conflicting or limited evidence was found for the effect of sealer type, obturation technique, and solvent use. The manual instrumentation increased the amount of AED compared to rotary instrumentation during the removal of filling materials (P<0.001). There was no significant difference in the amount of AED between the use of rotary and reciprocating files during the removal of filling materials (P=0.181).

Conclusion

Rotary instruments can be recommended instead of manual instruments during the removal of filling materials to control the amount of AED. Further studies with a low risk of bias are needed to clarify the effect of other treatment variables on AED during NSRCRT.

Bacteriologic Conditions of the Apical Root Canal System of Teeth with and without Posttreatment Apical Periodontitis: A Correlative Multianalytical Approach

INTRODUCTION

This study used a correlative multianalytical approach to investigate the bacteriologic conditions in the apical root canal system of treated teeth with or without apical periodontitis and their correlation with the technical quality of the previous root canal obturation and the presence and volume of apical periodontitis lesions.

METHODS

Root apexes were obtained from recently extracted root canal-treated teeth with (n = 23) and without (n = 22) apical periodontitis lesions as demonstrated by cone-beam computed tomographic examination. The root apexes were sectioned and subjected to micro-computed tomographic (micro-CT) scanning. The specimens were cryopulverized, and DNA extracted from the powder was used as a template in real-time polymerase chain reaction assays to quantify total bacteria and members of the Streptococcus genus and Actinobacteria phylum. The bacteriologic findings were compared between the 2 groups and also evaluated for associations with cone-beam computed tomographic and micro-computed tomographic data.

RESULTS

Bacteria were detected in all apical canal samples except 1. The mean counts of total bacteria, streptococci, and actinobacteria did not differ significantly between teeth with or without apical periodontitis (P > .05). Streptococcus levels were significantly lower by 80% in the apical canals of teeth with small lesions compared with those without lesions (P < .05). The limit of filling >2 mm short was significantly associated with more total bacterial counts compared with canals filled 0-2 mm short (P < .05). An adequate coronal restoration was significantly associated with lesser counts of Streptococcus (P < .05).

CONCLUSIONS

Comparable bacterial loads were observed in the apical canal system of treated teeth with and without apical periodontitis, suggesting that factors other than only the total bacterial levels may also influence the development and progression of apical periodontitis. Bacteria were found in the apical canal in virtually all cases with a high prevalence of streptococci and actinobacteria. Streptococci counts were significantly higher in the apical canal of teeth with inadequate restorations and teeth with no lesions. Underfilled canals showed higher bacterial counts.

A novel simplified approach for endodontic retrograde surgery in short single-rooted teeth

BACKGROUND

High technical thresholds, long operative times, and the need for expensive and specialized equipment impede the widespread adoption of endodontic microsurgery in many developing countries. This study aimed to compare the effects of a simplified, cost-effective, and time-efficient surgical approach involving orthograde obturation using biological ceramic material greater than 6 mm combined with apicoectomy for single-rooted teeth with short lengths with those of the conventional and current standard methods.

MATERIALS AND METHODS

Forty-five premolars equally categorized into three groups: conventional surgery group, standard surgery group, and modified surgery group. A µCT scan was used to calculate the volume of voids. A micro-leakage test and scanning electron microscope (SEM) were performed to assess the sealing effect. Additionally, four cases of chronic periapical periodontitis in the anterior region were selected, and the patients received either the modified approach or the standard surgery for endodontic microsurgery.

RESULTS

The volumes of voids in the apical 0-3 mm of the modified group and the standard group were comparable. The micro-leakage test and SEM examination demonstrated closely bonded fillings in the dentinal walls in both the modified surgery group and standard surgery group. The outcomes of the preliminary application of this modified procedure on patients were successful at the time of the follow-up cutoff.

CONCLUSIONS

The modified surgery group exhibited similar root canal filling and apical sealing abilities with the standard procedure for single-rooted teeth with short lengths (< 20 mm). The preliminary application of this modified surgical procedure achieved favorable results.

Microcomputed tomography (micro-CT) analysis of apical mandibular premolar in relation to clinical sign presentation: An in vitro study

Introduction

Variations in anatomic apex and apical foramina of root canals are common in different teeth types. The sophisticated 3D micro-CT aids researchers in investigating the apical morphology, such as the apical foramen (AF) and constriction (AC).

Objectives

To measure the length between the foramen and the apex and the physiological length to the apex, in lower premolar teeth. Furthermore, a measurement was conducted on the average length from the foramen to the apex of the lower premolar teeth with respect to the presence of clinical and non-clinical signs.

Methods

A total of 80 lower premolar teeth were selected based on the inclusion criteria. All samples were scanned using micro-CT ZEISS X-Radia (17 µm), and the datasets were analysed. The root canal AF and AC were reconstructed using Drishti software (V3.0) by utilising a 4-digit system code in millimetres (mm).

Results

More than half of the lower premolars (n = 47, 58.8 %) demonstrated a clinical signs presentation, while the rest had a non-clinical sign (n = 33, 41.3 %). There was a significant difference (p = 0.013) between the non-clinical and clinical groups in the mean length from the apical foramen to the apex (AFA) at 0.59 mm and 0.47 mm, respectively. Meanwhile, the non-clinical and clinical mean length from apical constriction to apex (ACA) were 0.75 mm and 0.73 mm, and the mean length from AF to AC (AFC) was 0.48 mm and 0.53 mm, respectively. Nonetheless, no significant differences were detected between the ACA and AFC of non-clinical and clinical groups.

Conclusion

The clinical signs presentation observed in lower premolars mainly affected the apical morphology, particularly the position and length of the root AF, and less so the AC position and length. Therefore, the information is useful for clinical purposes.

Evaluation of interfacial adaptation and penetration of bioceramic-based sealers in oval root canals: A confocal laser scanning microscope study

To assess the interfacial adaptation and penetration depth of three different bioceramic-based sealers (CeraSeal, EndoSeal MTA, Nishika Canal Sealer BG) compared to an epoxy resin-based sealer (AH Plus) in oval root canals. Fourty extracted single-rooted mandibular premolar with oval canal were prepared and randomly allocated according to the obturation into; CeraSeal, EndoSeal MTA, Nishika Canal Sealer BG and AH Plus. The roots were sectioned at 3, 6 and 9 mm from the apex. The sealer adaptation and the penetration depth were evaluated under confocal laser scanning microscope. One-way ANOVA and Repeated measure ANOVA were used to statistically analyze the data. Nishika Canal Sealer BG showed significantly higher sealer adaptation than EndoSeal MTA (P < .001) at apical and middle thirds. Meanwhile, AH Plus showed significantly higher sealer adaptation than EndoSeal MTA (P = 0.011) at middle third. For sealer penetration, Nishika Canal Sealer BG showed the longest sealer penetration that was significant compared to AH Plus (P < .001) and EndoSeal MTA (P < .001) whereas CeraSeal was significantly higher than EndoSeal MTA (P = 0.029) at coronal third. For AH Plus, there was a significant less sealer penetration at coronal third compared to apical and middle thirds (P < .05). Whereas for EndoSeal MTA, the coronal third has significant less penetration compared to the middle third (P = 0.032). Endoseal has the lowest adaptation and penetration depth. Nishika Canal Sealer BG has better adaptation and penetration depth using single cone obturation technique in oval canal. RESEARCH HIGHLIGHTS: All the tested root canal sealers have some percentage of gaps and vary in their penetration capability into dentinal tubules. Nishika Canal Sealer BG has significantly better sealer adaptation to root dentinal walls than that of EndoSeal MTA at the apical and middle third but not significantly different from other type of sealers used. Nishika Canal Sealer BG has significantly better penetration depth than AH Plus and EndoSeal MTA at the coronal third of radicular dentin.

The Bond Strength of Root Canal Filling after Calcium Hydroxide Removal with a Simple Apical Negative Pressure Kit in Oval-Shaped Root Canal

Background

The aim of this study was to evaluate the effect of a simple irrigating device, which produced from the apical negative pressure concept, as a final irrigating method after calcium hydroxide (CH) medication on the bond strength of epoxy resin-based sealer in the oval-shaped root canal.

Methods

Forty-eight single-rooted premolars with oval-shaped canals were included in the study. The crown was decoronized and canal instrumented with Mtwo (VDW GmbH, Munich, Germany) up to size 40/04. The specimens were assigned to four groups according to the irrigation protocol after 1 week of CH medication: control group (no medication) and three experimental groups conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI), and simple apical negative pressure kit (sANP). The teeth were obturated with a warm vertical technique using epoxy resin-based sealers. After 1 week, the roots were transversally sectioned at coronal, middle, and apical thirds. A push-out test was performed by a universal testing machine, and statistical analysis was performed using One-Way ANOVA with Duncan's post hoc test.

Results

The bond strength in the control group was significantly higher than the CNI group in all root canal thirds (P < 0.05). At coronal third, sANP showed lower bond strength than PUI group (P < 0.05). However, the bond strength of sANP group was comparable to the control group (P > 0.05) which was significantly higher than the PUI group at apical third (P < 0.05).

Conclusion

A sANP enhanced the bond strength of epoxy resin-based sealer in the apical third of CH-medicated root canal in the oval-shaped canal.

New Ultrasonic Tip for Root Canal Filling of the Mesial Canals of Mandibular Molars with Isthmus: A Laboratory Evaluation Using Computed Microtomography

INTRODUCTION

The obturation quality of the mandibular molar mesial canals and isthmuses with two thermoplastic techniques, ultrasonic vertical condensation (UVC) and continuous wave of condensation (CWC), was evaluated using computed microtomography (μCT).

METHODS

Thirty-six human mandibular molars had been previously scanned and analyzed using μCT for mesial roots with morphologically similar isthmuses for this study. Coronal access and confirmation of foraminal patency were performed, and the actual length of the teeth was established using a clinical microscope (40X magnification). The canals were prepared using ProTaper Gold instruments up to #F3, with 2.5% sodium hypochlorite as the irrigant solution, followed by a passive ultrasonic irrigation protocol. The specimens were randomly divided into the UVC and CWC groups based on the obturation technique to be used. Obturation was performed with #F3 gutta-percha cones cemented using AH Plus Jet sealer. The μCT scans were performed after 15 days, and the images were evaluated by a calibrated examiner blinded to the experimental groups to determine the filling rate of the entire canal area, including the main canal and isthmus. Student's t-test was used for statistical analysis; P values ≤0.05 were considered significant.

RESULTS

Neither of the thermoplastic obturation techniques achieved complete filling of the canals (86.3% for UVC and 91.4% for CWC), with a statistically significant difference between them (P = .029).

CONCLUSIONS

Under the conditions of the study, it can be concluded that none of the techniques completely filled the canal/isthmus of the mandibular molars; however, the CWC exhibited better performance.

Comparative volumetric analysis of three different obturating materials in primary molars under cone beam computed tomography: an in-vitro study

BACKGROUND

To increase the success rate of the endodontic treatment in primary teeth various, obturating materials have been introduced to meet the specific requirements for deciduous dentition and to create a three-dimensional (3D) seal to prevent recurrence of bacterial infection. This study was conducted to compare and evaluate the three-dimensional seal and volumetric filling of primary canals obturated with different medicaments using cone beam computed tomography (CBCT).

METHODS

In-vitro cross sectional study was designed with sample size of 108 specimens. Thirty-six extracted primary molars were selected for the study and randomly divided into 3 groups A (Metapex; Meta Biomed, Osong-eup, Korea), B (Endoflas; Sanlor Laboratories, Cali, Colombia) and C (Zinc oxide eugenol; DPI India Ltd., Mumbai, India). After access opening, canals were prepared up to 30 no k- file followed by obturation with Metapex, Endoflas and Zinc oxide eugenol in respective groups. CBCT was done before and after the obturation for volumetric analysis. The data obtained were analyzed to attain POV (percentage of obturated volume) and PVV (percentage volume of voids).

RESULTS

The percentage of obturated volume (POV) was highest for Endoflas group (88.87) followed by Metapex (83.58) and ZnO (72.78) and the difference was statistically significant. Whereas the percentage volume of voids (PVV) was more in Zinc oxide eugenol group (27.22) followed by Metapex (16.42) and least voids were seen in Endoflas group (11.14).

CONCLUSIONS

Voids were found in all three obturating materials. Endoflas showed superior three-dimensional (3D) sealing capability whereas ZnO eugenol having least sealing capacity.

Efficacy of Endoscope and Periapical Radiography to Detect Residual Root Canal Filling Using Micro-CT as Reference

INTRODUCTION

To evaluate the efficacy of examinations by endoscope of root canals to determine residual root canal filling materials by comparison with microcomputed tomographic (micro-CT) images as reference.

METHODS

Thirty maxillary second premolars with oval canals received root canal treatment. Then D-Race retreatment files were used to remove the root canal fillings supplemented by XP-endo Finisher. Samples were scanned to reconstruct micro-CT reference images. Images were obtained of all samples from the mesiodistal and buccolingual directions by digital radiography. Then the root canals of specimens mounted in manikins were assessed by endoscope. The radiographic and endoscopic results were scored following comparison with the micro-CT images, which served as a reference, by 2 blinded observers. The interexaminer reliability of the assessments was evaluated by kappa test and the accuracy of endoscopic visualization according to the presence of residual root canal filling materials was compared using Kruskal-Wallis H test and Spearman's rank order correlation with the level of significance set at 5%.

RESULTS

The efficiency of the periapical radiography and endoscopy to determine residual root canal filling material was similar in every third of the root canal (P > .05).

CONCLUSIONS

The endoscope detected residual root canal filling material as efficiently as periapical radiography.

A Micro-CT Analysis of Initial and Long-Term Pores Volume and Porosity of Bioactive Endodontic Sealers

The evaluation of the porosities within the interface of root canals obturated with endodontics materials is extremely important for the long-term success of endodontic treatments. The aim of this study was to compare initial and long-term volume of pores (total, open, closed) and porosity (total, regional) of three bioactive endodontic sealers: GuttaFlow Bioseal, Total Fill BC Sealer, and BioRoot RCS. Root canals were obturated with three “bioactive” sealers using the single-cone technique. The volume of open and closed pores and porosity were calculated using a micro-computed tomography (MCT) method. The measurements were performed after 7 days (initial) and after 6 months (long-term) of incubation. Statistical significance was considered at p < 0.05. The total volume of pores remained unchanged after the 6-month storage. GuttaFlow Bioseal exhibited significantly higher long-term volume in open pores than Total Fill BC Sealer. The total porosity in all the tested sealers presented no statistically significant change after the 6-month storage, except for BioRoot RCS. The total porosity values of this latter material significantly increased after long-term incubation, especially in the apical region. In conclusion, the use of bioactive sealers with excessive tendency to create porosities both in shorth- and long-term periods of storage may compromise the long-term success of endodontic treatments.

A critical analysis of research methods and experimental models to study root canal fillings

Canal filling materials and techniques have been one of the most studied topics in Endodontics. A simple search using the mesh term "root canal filling" in PubMed revealed more than 11,000 articles, an impressive number that is much higher than "root canal disinfection" (5,544 articles) or even the popular "root canal preparation" (8,527 articles). The overriding importance attributed to root filling procedures is not merely intuitive. It derived from the appealing relevance given by the appearance of the white lines in common radiographs grounded on retrospective clinical data that had identified the quality of a root filling as one of the major causes of treatment failure (lack of healing). Since the publication of the Washington study, impressive efforts have been made for the release of new materials and techniques, as well as, for the development of a plethora of laboratory methods to assess the quality of root filling procedures. This narrative review aims to address and discuss the most relevant laboratory methods to assess the root canal filling. Since filling quality improvements have not translated into higher success rates, as reported in longitudinal clinical studies, more than to deliver a simple methodology-based review, this paper aims to present an in-depth critical view on the assessment of laboratory methods used to study the filling materials and techniques. Recent data indicate that the long-term dimensional stability/degradation over time of endodontic sealers plays a central role in the treatment outcome. In this context, laboratory methods should be developed focusing on predicting, at least to some degree, the long-term clinical behaviour of root canal fillings, rather than simply ranking different materials or techniques.

The dentine-sealer interface: modulation of antimicrobial effects by irrigation

AIM

Assess whether sodium hypochlorite (NaOCl) or chlorhexidine (CHX) and two irrigation protocols may alter the antibacterial properties of dentine and three endodontic sealers using a novel ex vivo tooth model.

METHODOLOGY

Prior to antibacterial testing, the tooth model was validated by means of scanning electron microscopy (SEM) to evaluate the separation between dentine and sealer surfaces. Root blocks prepared from extracted human roots were pretreated with 17% EDTA + 0.9% saline and subsequently treated with 1% NaOCl (G1), 2% CHX (G2) or no irrigant (G3). Two irrigation protocols were further investigated, "1% NaOCl + 17% EDTA" (P1) and "1% NaOCl + 17% EDTA + 2% CHX" (P2). Following irrigation, the root blocks were either filled with AH Plus, BioRoot RCS and Pulp Canal Sealer (PCS), or left empty. All groups were incubated for 1, 7 and 28 days. Direct contact tests for planktonic E. faecalis and 48 hours E. faecalis biofilms were performed at the level of dentine and sealer surfaces. Statistical analysis was performed on the bacterial survival between irrigants (G1, G2 and G3) and between irrigation protocols (P1 and P2) (p<0.05).

RESULTS

The model was considered reproducible as SEM examination of dentine samples indicated consistent separation between dentine and sealer surfaces. Irrigation with CHX (G2) and irrigation protocol (P2) enhanced the antibacterial properties of dentine without sealer application as well as dentine in contact with all three sealers tested, especially against planktonic E. faecalis. G2 and P2 also improved the antibacterial effect of AH Plus surfaces for all three incubation times. No irrigation groups (G1, G2) or irrigation protocols (P1, P2) altered the antibacterial properties of BioRoot RCS surfaces against planktonic bacteria or biofilms. Only BioRoot RCS surfaces eliminated the planktonic E. faecalis in all irrigation groups (G1, G2, G3) and protocols (P1, P2) investigated while PCS surfaces eliminated E. faecalis in biofilms in all groups up to 7 days.

CONCLUSIONS

The tooth model was reproducible. CHX improved the antibacterial activity upon both sealer and dentine surfaces. Among sealers, BioRoot RCS was less affected by NaOCl and CHX, and exhibited high antibacterial properties regardless the irrigation applied.

A micro-computed tomographic assessment of oval-shaped root canals obturated with bioceramic sealer using different obturation techniques

Background/Aim: To evaluate void volumes in oval-shaped root canals obturated with three different obturation systems using microcomputed tomography (micro-CT). Material and Methods: Twenty-four distal roots of mandibular molar teeth canals were prepared and randomly divided into three groups (n = 8 in each group). The canals were obturated using single cone (SC), GuttaCore (GC), and warm vertical compaction (WVC) techniques. Each specimen was scanned using a micro-CT device. The volumes of the voids were calculated, and the data were statistically analyzed using a one-way analysis of variance and post hoc Tukey's (P < .05). Results: The void volumes in the WVC group were significantly lower than those in the other groups (P < .05). When different root canal parts were examined, the void volumes increased significantly from the apical to the coronal level in the GC and SC groups (P < .05). In the WVC group, most voids were observed in the middle part (P < .05), whereas there was no significant difference in void volumes in the coronal and apical parts (P > .05). Conclusions: None of the systems provided void-free root filling. However, the void volume using the WVC system was significantly lower than that observed using the other systems.

Comparison of Obturation Quality between Calcium Silicate-Based Sealers and Resin-Based Sealers for Endodontic Re-treatment

BACKGROUND

The objective of this micro-computed tomography (micro-CT)-based study was to compare the filling quality of endodontic treatment and endodontic Re-treatment between two sealers with matched obturation techniques: calcium silicate-based sealer (Endoseal TCS) with a single-cone technique (SCT) and resin-based sealer (AH Plus) with a continuous wave technique (CWT).

METHODS

Forty maxillary premolars were selected and assigned into four groups, according to the obturation methods of the first endodontic treatment and Re-treatment (n = 10). The AP/AP group was first treated with AH Plus/CWT, then re-treated with AH Plus/CWT. The AP/ET group was first treated with AH Plus/CWT, then re-treated with Endoseal TCS/SCT. The ET/AP group was first treated with Endoseal TCS/SCT, then re-treated with AH Plus/CWT, and the ET/ET group was first treated with Endoseal TCS/SCT, then re-treated with Endoseal TCS/SCT. The specimens were scanned using micro-CT at three time points: after the first endodontic treatment, after gutta-percha (GP) cone removal, and after Re-treatment. The void volume of root canal obturation and the volume of the remaining filling materials were calculated. Data were analyzed using Student's t-tests and ANOVA.

RESULTS

The Endoseal TCS groups (ET/AP and ET/ET) showed a lower percentage of voids than the AH plus groups (AP/AP and AP/ET) on the whole canal and the apical third, after first obturation (p < 0.05). The AH plus group showed significantly fewer remnants than the Endoseal TCS group after GP removal (p < 0.05). Re-treated canals and initially treated canals had similar void volumes (p > 0.05). There was no significant difference in void volume after Re-treatment, regardless of whether the same or different sealers were used for the first treatment and Re-treatment (p < 0.05).

CONCLUSIONS

Endoseal TCS sealer and AH Plus sealer had a similar Re-treatment efficacy, regardless of which sealer was used in the previous treatment.

Dens invaginatus: clinical implications and antimicrobial endodontic treatment considerations

Dens invaginatus or dens in dente is a developmental dental anomaly resulting from an invagination of the enamel organ into the dental papilla during odontogenesis. Radiographically, it is usually seen as a radiolucent invagination surrounded by a radiopaque area (enamel) limited to the tooth crown or extending into the root. Because the invagination is opened to the oral cavity, it can retain saliva, food remnants, and bacteria. In conditions that the enamel lining of the invagination is naturally absent or lost due to caries, bacterial cells and products can diffuse from the invagination through the dentin tubules to reach the pulp and cause disease. Management of teeth with dens invaginatus include preventive sealing or filling of the invagination, or, if the pulp is affected, therapeutical options include vital pulp therapy, nonsurgical root canal treatment, apexification or regenerative endodontic procedures, periradicular surgery, intentional replantation, or extraction. It is recommended that the invagination be always approached, regardless of the type of dens invaginatus. The root canal should be treated whenever the pulp is irreversibly inflamed or necrotic. Endodontic management of teeth with dens invaginatus is often tricky because of its anatomical complexity, and special and customized strategies should be devised. This review discusses the endodontic implications of this anomaly and the current treatment recommendations based on anatomic, pathologic, and technologic considerations.

Micro-computed Tomographic Evaluation of the Quality of Root Canal Fillings in Mandibular Molars after Obturation for 54 Months

INTRODUCTION

The present study evaluated the percentage volume of voids in root canals of mandibular molars that had been obturated for 54 months.

METHODS

Thirty extracted human mandibular molars were instrumented and debrided. The teeth were assigned to 3 groups (n = 10) according to the filling technique and sealer used: the single-cone technique using AH Plus sealer (AHS; Dentsply Sirona Endodontics, Tulsa, OK) or EndoSequence BC sealer (BCS; Brasseler USA Dental LLC, Savannah, GA) and the warm vertical compaction technique using AH Plus sealer (AHW). The specimens were stored at 37°C and 100% humidity. Micro-computed tomographic imaging was used to scan each specimen 1 day 54 months after obturation. Data were analyzed using 1-way analysis of variance and the paired t test.

RESULTS

The percentage volume of voids in the teeth 1 day after obturation in the AHS group was higher than in the BCS group and the AHW group (P < .05). After 54 months, the proportion of voids decreased in all groups (P < .05). No significant difference was observed between the AHS group and the BCS group after 54 months. Teeth in the AHW group contained fewer voids than the AHS group (P < .05).

CONCLUSIONS

Voids in root canal filling were reduced 54 months after obturation. The warm vertical compaction technique achieved better root canal filling quality in mandibular molars than the single-cone technique when using AHS after long-term storage at 100% humidity.

Comparison of Various Root Canal Filling Materials and Obturation Techniques for Primary Teeth Using Microcomputed Tomography

Aim:

The aim of this study was to compare the effectiveness of different filling materials and obturation techniques for root canal obturation in primary teeth.

Materials and Methods:

Eighty maxillary primary incisors were included in this in vitro study. After biomechanical preparation, all samples were scanned using microcomputed tomography (micro-CT) and root canal volumes were calculated. Samples were grouped according to filling materials and obturation techniques, with ten samples in each group. The samples were filled with zinc oxide eugenol (ZOE) and Vitapex using four different obturation techniques (local anesthesia syringe, lentulo spiral, pastinject, and lentulo spiral–ultrasonic activation). After filling, samples were scanned a second time using micro-CT and root canal volumes were calculated. The statistical analysis was performed using SPSS version 24.0. Data were analyzed by Kruskal–Wallis and Mann–Whitney U tests.

Results:

When the ZOE and Vitapex were compared, it was observed that there were no significant differences between their postobturated volumes, percentage obturated volume (POV), internal void (IV), and percentage of internal void volume (PIV) ( P > .05). The local anesthesia syringe group had a significantly lower postobturated volume and POV, and a significantly higher IV and PIV for both filling materials than that by the other groups ( P < .05). There was no significant difference between the other obturation techniques ( P > .05). For the local anesthesia syringe group, postobturated volume and POV were significantly higher and IV and PIV were significantly lower with Vitapex than with ZOE ( P < .05). There was no significant difference between the other obturation techniques filled either with ZOE or Vitapex ( P > .05).

Conclusion:

Except for the syringe technique, no difference was observed between the ZOE and Vitapex materials. The syringe technique used in the primary root canal filling was less effective than the other techniques, which had similar efficacy, and in this technique, more effective canal filling was achieved with Vitapex.

Long-term porosity and retreatability of oval-shaped canals obturated using two different methods with a novel tricalcium silicate sealer

OBJECTIVE

To evaluate the percentage volume of voids and gaps in oval-shaped canals obturated using two different methods with a tricalcium silicate-based sealer after short- or long-term storage. The long-term effect of storage on the efficiency of removing filling material was also investigated.

MATERIALS AND METHODS

Forty premolar teeth with oval-shaped canals were instrumented to Reciproc R25 and obturated using single cone obturation (SCO) or warm vertical compaction (WVC) techniques with gutta-percha and HiFlow sealer. The specimens were stored at 100% humidity and 37°C for 2 weeks or 6 months and scanned using micro-computed tomography. Initial retreatment was performed up to a Reciproc R40, and the operating time was recorded. The residual material in the canal received a supplementary procedure using XP-endo Finisher R (XPFR) files. After each retreatment procedure, the specimens were rescanned.

RESULTS

The percentage volume of voids and gaps in the SCO group was higher than that of the WVC group at both 2 weeks and 6 months (P < 0.05). The percentage volume of the filling material removed after initial retreatment and XPFR cleaning was significantly higher in the 6-month group than in the 2-week groups (P < 0.05). The proportion of the residual material decreased significantly when XPFR files were used, compared to the initial retreatment group (P < 0.05) in both storage times.

CONCLUSION

The efficiency of retreatment in the oval-shaped canal was closely related to the storage time rather than the filling technique using a tricalcium silicate sealer. The XPFR instrument proved effective in the removal of the remaining materials from the oval-shaped canal.

CLINICAL RELEVANCE

Obturation of the oval-shaped canal with TSBS using the SCO technique in the coronal area needs to be optimized. The retreatment was less efficacious in freshly filled canals than aged filled canals.

Complete Obturation-Cold Lateral Condensation vs. Thermoplastic Techniques: A Systematic Review of Micro-CT Studies

To prevent re-infection and provide a hermetic seal of the root canal system, an endodontist must aim to produce a void-free obturation. This review aimed to compare the completeness of root canal obturation between the two most prevalent methods-cold lateral condensation and warm gutta-percha techniques-using micro-CT (PROSPERO reg no. 249815).

MATERIALS AND METHODS

A search of Scopus, Embase, PubMed (Medline via PubMed), and Web of Science databases was done without any time restriction according to the PRISMA protocol. Articles that compared both techniques and were published in English were included. Data was extracted and the risk of bias was assessed using an adapted tool based on previous studies.

RESULTS

A total of 141 studies were identified by the search. Following the screening and selection of articles, 9 studies were included for review. Data was extracted manually and tabulated. Most studies had a moderate risk of bias. None determined operator skill in both methods before comparison. The data extracted from the included studies suggests that both techniques produce voids in the obturation. The thermoplasticized gutta-percha techniques may result in fewer voids compared to cold lateral condensation.

CONCLUSION

Considering the limitations of the included studies, it was concluded that neither technique could completely obturate the root canal. Thermoplasticized gutta-percha techniques showed better outcomes despite a possible learning bias in favor of cold lateral condensation. Establishing operator skills before comparison may help reduce this bias.

Calcium Silicate-Based Root Canal Sealers: A Narrative Review and Clinical Perspectives

Over the last two decades, calcium silicate-based materials have grown in popularity. As root canal sealers, these formulations have been extensively investigated and compared with conventional sealers, such as zinc oxide-eugenol and epoxy resin-based sealers, in in vitro studies that showed their promising properties, especially their biocompatibility, antimicrobial properties, and certain bioactivity. However, the consequence of their higher solubility is a matter of debate and still needs to be clarified, because it may affect their long-term sealing ability. Unlike conventional sealers, those sealers are hydraulic, and their setting is conditioned by the presence of humidity. Current evidence reveals that the properties of calcium silicate-based sealers vary depending on their formulation. To date, only a few short-term investigations addressed the clinical outcome of calcium silicate-based root canal sealers. Their use has been showed to be mainly based on practitioners' clinical habits rather than manufacturers' recommendations or available evidence. However, their particular behavior implies modifications of the clinical protocol used for conventional sealers. This narrative review aimed to discuss the properties of calcium silicate-based sealers and their clinical implications, and to propose rational indications for these sealers based on the current knowledge.

Volume Percentage of Filling Voids in Root Canals Prepared by a Novel Nickel-Titanium Rotary System (TruNatomy) Using Two Different Obturation Techniques

This study aimed to compare the volume percentage of filling voids in root canals prepared with a newly introduced rotary system, TruNatomy (Dentsply Maillefer), and obturated by the modified continuous wave (CW) or single cone (SC) filling technique. Plastic tooth models with four canals were enlarged by using TruNatomy files and randomly allocated into either the CW or SC group. The volume percentage of filling voids at 1–6 mm from the apex was analyzed by using microcomputed tomography; mean values were compared by using independent two-sample t-tests (p < 0.05). The mean volume percentages of the filling voids were 2.81 ± 1.11% and 1.77 ± 0.82% in the CW and SC groups, respectively. In the apical area (1–4 mm), volume percentages in the palatal were significantly different between the CW and SC groups; in the middle area (4–6 mm), volume percentages in the palatal and the second mesiobuccal canals were significantly different (p < 0.05). The SC group showed lower volume percentages of filling voids than the CW group. The canals prepared by the TruNatomy system can be obturated well by both the SC and CW techniques. The SC technique showed a lower number of voids, especially in the palatal canals.

Ultrasonic vibration and thermo-hydrodynamic technique for filling root canals: Technical overview and a case series

AIM

To present a novel root canal filling technique: Ultrasonic Vibration & Thermo-Hydrodynamic Obturation (VibraTHO), and its rationale with a series of cases.

SUMMARY

The VibraTHO technique was used to fill the root canals of three clinically challenging cases: A C-shaped mandibular molar with complex anatomy, a C-shaped mandibular molar with an infected root canal system and a periapical lesion that required retreatment, and apically bifurcating mesiobuccal canals with a common orifice in a maxillary second molar. The cases were followed up for 15, 7 and 37 months, respectively. After follow-up, normal periapical status was observed without any noticeable radiographic change in the root canal fillings in each case. Periapical radiographs revealed complete healing of the periapical area in cases with pre-operative periapical lesions.

Micro-computed tomographic evaluation of single-cone obturation with three sealers

Objectives

This study used micro-computed tomography (µCT) to compare voids and interfaces in single-cone obturation among AH Plus, EndoSequence BC, and prototype surface pre-reacted glass ionomer (S-PRG) sealers and to determine the percentage of sealer contact at the dentin and gutta-percha (GP) interfaces.

Materials and Methods

Fifteen single-rooted human teeth were shaped using ProTaper NEXT size X5 rotary files using 2.5% NaOCl irrigation. Roots were obturated with a single-cone ProTaper NEXT GP point X5 with AH Plus, EndoSequence BC, or prototype S-PRG sealer (n = 5/group).

Results

The volumes of GP, sealer, and voids were measured in the region of 0–2, 2–4, 4–6, and 6–8 mm from the apex, using image analysis of sagittal µCT scans. GP volume percentages were: AH Plus (75.5%), EndoSequence BC (87.3%), and prototype S-PRG (94.4%). Sealer volume percentages were less: AH Plus (14.3%), EndoSequence BC (6.8%), and prototype S-PRG (4.6%). Void percentages were AH Plus (10.1%), EndoSequence BC (5.9%), and prototype S-PRG (1.0%). Dentin-sealer contact ratios of AH Plus, EndoSequence BC, and prototype S-PRG groups were 82.4% ± 6.8%, 71.6% ± 25.3%, and 70.2% ± 9.4%, respectively. GP-sealer contact ratios of AH Plus, EndoSequence BC, and prototype S-PRG groups were 65.6% ± 29.1%, 80.7% ± 25.8%, and 87.0% ± 8.6%, respectively.

Conclusions

Prototype S-PRG sealer created a low-void obturation, similar to EndoSequence BC sealer with similar dentin-sealer contact (> 70%) and GP-sealer contact (> 80%). Prototype S-PRG sealer presented comparable filling quality to EndoSequence BC sealer.

The effect of different confluence confirmation strategies on the obturation of Vertucci type II canal: micro-CT analysis

Objectives

The present study aims to compare the obturation quality of 2 confluence confirmation techniques in artificial maxillary first premolars showing Vertucci type II root canal configuration.

Materials and Methods

Thirty artificial maxillary premolars having Vertucci type II root canal configuration were made. They were divided into 3 groups according to the confluence confirmation technique as follows. Gutta-percha indentation (GPI) group (confluence confirmation using a gutta-percha cone and a K file); electronic apex locator (EAL) group (confluence confirmation using K files and EAL); and no confluence detection (NCD) group. In the GPI group and the EAL group, shaping and obturation were performed with the modified working length (WL). In the NCD group, shaping was performed without WL adjustment and obturation was carried out with an adjusted master cone. Micro-computed tomography was used before preparation and after obturation to calculate the percentage of gutta-percha occupied volume (%GPv) and the volume increase in the apical 4 mm. Data were analyzed using 1-way analysis of variance and post hoc Tukey's test.

Results

Statistically significant difference was not found in terms of the %GPv from the apex to apical 4 mm. However, the NCD group showed a statistically significant volume increase compared with the EAL group (p < 0.05).

Conclusions

In terms of gutta-percha occupied volume, no significant difference was observed among the 3 groups. Confluence confirmation using an EAL in teeth with Vertucci type II configuration showed less volume increase during canal shaping compared with no confluence confirmation.

Microcomputed Tomographic Assessment of the Single Cone Root Canal Fillings Performed by Undergraduate Student, Postgraduate Student and Specialist Endodontist

The present study evaluated the obturation quality of root canals filled with BioRoot RCS sealer and single gutta-percha point by undergraduate student (US), postgraduate student (PS) and endodontist (ED). Twenty-one plastic models of upper premolars were enlarged with HyFlex EDM instruments to a size 40/0.04 taper and randomly divided into three groups (7 teeth/14 canals per group): US, PS and ED. After the obturation of root canals with BioRoot RCS and one HyFlex EDM size 40 gutta-percha point, plastic models were scanned using micro-computed tomography scanner (µCT) SkyScan 1272 at isotropic resolution of 10 µm. The porosity distribution was evaluated separately for the apical, middle and coronal thirds. The Kruskal–Wallis, Mann–Whitney, Friedman and Wilcoxon tests with the significance level set at 5% were used for data analysis. The µCT evaluation revealed open pores being the dominant type of porosity in all experimental groups and root canal thirds, with the highest percentage of pores in the apical third of root canal fillings. The quality and homogeneity of single cone root canals fillings remained similar between the groups in the apical and middle thirds (p > 0.05). Significant differences were observed only in the coronal third (p < 0.05).

Correlation among Root Canal Configuration, Quality of Filling, and Its Sealability

Objective  This study aimed to evaluate the existence of possible correlations among root canal configuration, quality of filling, and its sealability.

Materials and Methods  Sixty human mandibular central incisors were selected for this study. The teeth were prepared with the Profile 04 system up to instrument 35/0.04 and irrigated with 2.5 mL of 2.5% sodium hypochlorite at each instrument change. Root canal filling was performed by the lateral compaction technique, using gutta-percha and an epoxy resin-based sealer (AH Plus) labeled with 0.1% Rhodamine B dye. Afterward, the specimens were submitted to fluid filtration tests to assess the sealability of the filling. Cross-sections were obtained at −3, −6, and −8 mm from the root apex and submitted to a metallographic treatment to determine the root canal configuration and the percentage of gutta-percha filled areas. The data were statistically analyzed by the Grubbs test. Pairs of correlations were analyzed by applying the Spearman test at a level of significance of 5%.

Results  No correlation was observed among the analyzed variables as follows: root canal configuration versus filling quality (Spearman’s rho = 0.031); filling quality versus sealability (Spearman’s rho = 0.219); and root canal configuration versus sealability (Spearman’s rho = 0.184).

Conclusion  The root canal configuration did not affect the quality of the filling and its sealability.

Effect of obturation technique using a new bioceramic sealer on the presence of voids in flattened root canals

The aim of this study was to evaluate the filling ability of a new ready-to-use calcium silicate-based sealer using thermoplastic or single-cone technique in flattened root canals. Twenty-four flattened distal canals of mandibular molars with a buccolingual diameter 4 or more times larger than the mesiodistal diameter were selected. The root canals were prepared and filled (n = 12), according to the following techniques: thermoplastic or single-cone technique using Bio-C Sealer. The teeth were scanned using Skycan 1176 micro-computed tomography (micro-CT) - voxel size 8.74 µm, before and after filling the root canal. The percentage of voids in the filled root canals was evaluated, and the data were statistically analyzed using the unpaired t-test (α = 0.05). The root canals filled using the thermoplastic technique created a smaller percentage of voids in the cervical/middle thirds than those filled using the single-cone technique (p < 0.05). There was no difference in the percentage of voids using either technique in the apical third (p > 0.05). The flattened root canals in the cervical/middle thirds were better filled using the ready-to-use calcium silicate-based sealer associated to the thermoplastic technique, compared with the single-cone technique. In the apical third, the techniques showed similar filling ability.

Influence of obturation technique on penetration depth and adaptation of a bioceramic root canal sealer

Aim:

Evaluation of the impact of three different obturation techniques on the penetration depth and adaptation of a bioceramic root canal sealer(BioRoot RCS) to root dentin using scanning electron microscope and confocal laser scanning microscope.

Materials and Methods:

Recently extracted ninety mandibular premolar teeth of similar dimensions (±0.2 mm) with single canals and straight roots were segregated into three experimental groups (n = 30 each) based on the method of obturation used, i.e., lateral compaction technique, warm vertical compaction technique, and injectable thermoplasticized technique. After obturation, half of the root samples (n = 15) in each group were sectioned horizontally by hard tissue microtome at 3, 6, and 9 mm, respectively, from root apex for measuring sealer penetration depth with a confocal laser scanning microscope. Longitudinal sections of the samples (n = 15) were used for measuring the adaptation of sealers to radicular dentin using a scanning electron microscope.

Statistical Analysis:

Intergroup comparison of sealer penetration depth and adaptation to root dentin was analyzed using one-way ANOVA, and pairwise comparisons were made using Tukey's post hoc test.

Results:

Warm vertical condensation technique showed deeper root dentin penetration of the sealer. Better adaptation of the sealer to apical root dentin with minimal voids (P ≤ 0.05) was achieved with warm vertical condensation in comparison to the injectable gutta-percha method and lateral condensation obturating techniques.

Conclusion:

At all three root levels (coronal, middle, and apical), warm vertical condensation technique exhibited more sealer penetration with minimum gaps, whereas lateral condensation technique exhibited more gaps and less sealer penetration.

Quality of Root Canal Filling Using a Bioceramic Sealer in Oval Canals: A Three-Dimensional Analysis

Objectives  The oval canals may be associated with inadequate debridement, which can affect the quality of the root canal filling, thus the treatment outcome. The aim of the present work was to compare the quality of oval canals fillings using EndoSequence BC sealer with the single-cone technique or cold lateral compaction.

Materials and Methods  Thirty-eight human single-rooted premolars with oval canals were instrumented to 1 mm from the apical foramen with hand nickel–titanium files, followed by circumferential filing with Hedstrom files. Teeth were paired into two groups based on their micro-computed tomography (CT) morphological parameters. Both groups were filled using EndoSequence BC sealer. The first used a single cone and the other with the cold lateral compaction technique. The voids volume was evaluated by micro-CT and the percentage was calculated for the total length and for the apical 5 mm of each canal. The Mann–Whitney U test was used to assess whether the surface area and obturation length differed significantly between the groups and to compare the percentage of voids for each technique.

Results  Both techniques resulted in less than 16% voids, with no statistically significant difference between them for the total canal length and for the apical 5 mm ( p > 0.05).

Conclusions  The quality of the obturation performed with the single-cone technique was similar to that achieved with lateral compaction using EndoSequence BC sealer in oval canals.

Comparison between immediate and delayed post space preparations: a systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis compared the effects of immediate and delayed post space preparation on apical sealing.

MATERIALS AND METHOD

Two independent authors conducted a systematic search (PubMed/Medline, Cochrane Library, and other databases, until February 2020) and a risk of bias evaluation. Only in vitro studies that compared the effects of immediate and delayed post space preparations on apical filling and adhesion of the post were eligible.

RESULT

Of the 742 articles retrieved, 32 were included. Most of the studies used single-rooted human teeth and rotary files for root canal preparation, a single-cone technique for the filling protocol, and rotary instruments for post space preparation. Various delayed preparation times were evaluated: 8-72 h, 5-30 days (mainly 7 days), and 4 months. In nine studies, the delayed groups showed more apical leakage, while four studies reported more leakage in the immediate groups; ten studies found no significant difference. One study found more bacterial penetration in the delayed group, whereas three studies showed no significant difference. One study reported more voids in the delayed group, while another found no such difference. Three studies showed better post-bond strength in the delayed group, one in the immediate group, whereas three found no significant difference in post-bond strength. Three studies employing varied sealers for root canal fillings were considered for meta-analysis. Two subgroup analyses were also performed (one concerning the use of resin-based sealers (AH Plus), another for zinc oxide-eugenol-based sealers). The results of the meta-analysis showed that a delayed post space preparation led to a significantly higher apical leakage than an immediate preparation (mean difference = 0.41 mm, confidence interval = 0.24-0.59, p < 0.001).

CONCLUSION

Delayed post space preparation seems to negatively influence apical sealing; however, further studies are needed to determine the influence of the timing of post space preparation on the other parameters.

CLINICAL RELEVANCE

Immediate post space preparation may be the safest clinical choice to prevent apical leakage.

Micro-CT evaluation of filling of flattened root canals using a new premixed ready-to-use calcium silicate sealer by single-cone technique

The aim of this study was to evaluate the filling ability of a new premixed ready-to-use calcium silicate-based sealer, in comparison with an epoxy resin-based sealer by the single-cone technique in flattened root canals. Thirty-two flattened root canals of maxillary second premolars with buccal-lingual diameter 4 or more times larger than the mesio-distal diameter at 9 mm from the radiographic apex were selected. Root canals were prepared using Hyflex EDM 25/0.08 and additional preparation with ultrasonic tip Flatsonic and ProDesign Logic 25/0.03. After preparation, the root canals were filled with two root canal sealers (n = 16): Bio-C Sealer or AH Plus using the single-cone technique. Scanning was performed before and after root canal obturation using a Skycan 1176 micro-computed tomography (micro-CT) with an isotropic voxel size of 8.74 μm. The percentage of voids was analyzed in the cervical/middle thirds and in the apical third. Data were submitted to the Mann-Whitney test at a significance level of 5%. There was no statistical difference between Bio-C Sealer and AH Plus (p > .05). The percentage of voids in the cervical/middle thirds was 8.94% (1.33-39.95) for Bio-C Sealer and 9.30% (1.19-18.00) for AH Plus (p > .05). In the apical third, this percentage was 11.84% (4.85-27.00) for Bio-C Sealer and 9.21% (1.34-28.78) for AH Plus (p > .05). By using the single-cone technique, neither Bio-C Sealer nor AH Plus provided a voids-free root canal filling. Both sealers had similar filling ability in flattened root canals.

Microscopic and chemical evaluation of the filling quality of five obturation techniques in oval-shaped root canals

OBJECTIVES

The aim of this study was to assess the filling quality of five obturation techniques in oval-shaped root canals.

MATERIALS AND METHODS

A total of 212 mandibular first molars with one distal oval canal were selected. Distal canals, shaped with WaveOne Gold Primary, were randomly divided in five groups (n = 40) for obturation: continuous wave condensation, GuttaCore, Thermafil, single cone with AH plus, and single cone with BioRoot RCS. The proportions of gutta-percha-filled areas (GPFA), sealer-filled areas (SFA), void areas (VA), and the sealer/gutta tags into dentinal tubules at 4 mm and 2 mm from the apex were analyzed by an optical numeric microscope, SEM, and energy-dispersive X-ray (EDX). Data were then compared by Kruskal-Wallis one-way ANOVA on ranks (α = 0.05).

RESULTS

At 4 mm, a statistically significant higher GPFA and lower SFA were observed in the GuttaCore and Thermafil groups compared with the 3 other groups. A statistically significant lower VA was observed in the continuous wave condensation, GuttaCore, and Thermafil groups than in the two single-cone groups. At 2 mm, there were a statistically significant higher GPFA and lower SFA and VA in GuttaCore and Thermafil groups than in the 3 other groups. At the two levels investigated, the presence of gutta-percha tags was clearly demonstrated for GuttaCore and Thermafil groups; no tags were observed in the 3 other groups.

CONCLUSIONS

Obturation quality was overall improved in GuttaCore and Thermafil groups.

CLINICAL RELEVANCE

Carrier-based techniques may significantly improve the filling quality compared to continuous wave condensation and single-cone technique. The single-cone technique might have inherent limitations especially in oval root canals regardless of the sealer used.

Filling Ability and Flow of Root Canal Sealers: A Micro-Computed Tomographic Study

This study evaluated by micro-computed tomography (μCT) the filling ability in curved root canals, besides the flow of AH Plus (AHP) and Neo MTA Plus (NMTAP) sealers using different methodologies. Mandibular molars mesial roots with two root canals and degree of curvature between 20° and 40° were selected. The specimens were prepared with the ProDesign R system up to size 35.05 and were filled with the sealers by a continuous wave of condensation technique, Thermo Pack II (n=12). The teeth were scanned using μCT after root canal preparation and obturation. The volumetric percentage of filling material and voids were calculated. Flow was evaluated based on ISO 6876/2012 (n=10). Flow and filling were also evaluated in μCT using a glass plate with a central cavity and four grooves from the central cavity (n=6). Flow was linearly calculated into the grooves. The central cavity filling (CCF) and lateral cavity filling (LCF) were calculated in mm³. Data were submitted to non-paired t test with a significance threshold at 5%. The percentage of filling and voids between the root canals filled with AHP or NMTAP was similar (p>0.05). NMTAP presented the lowest flow in conventional test (p<0.05). Using μCT, sealers had similar CCF, LCF and linear flow (p>0.05). In conclusion, NMTAP and AHP had similar filling ability in curved mesial root canals of mandibular molars without presence of isthmus. Although AHP presented better flow than NMTAP using ISO methodology, there was no difference between these materials regarding volumetric filling when evaluated by μCT.

Physicochemical and Antibacterial Properties of Novel, Premixed Calcium Silicate-Based Sealer Compared to Powder-Liquid Bioceramic Sealer

The aim of this study was to compare the physicochemical properties, filling ability, and antibacterial activity of a premixed calcium silicate-based sealer to those of a powder–liquid bioceramic sealer. Ceraseal (CS) and BioRoot (BR) materials were analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy at 7 and 14 d of immersion in distilled water. The filling ability of the two sealers as well as the water contact angle, solubility, flow, roughness, crystalline microstructure, pH, and compressive strength were also evaluated. The antibacterial activity was assessed through an agar diffusion as well as through direct tests. All the results were statistically analyzed using one-way or two-way analysis of variance tests. Statistically significant lower void percentages were observed for CS at 2 and 8 mm from the working length (WL) compared to those for the BR group, whilst no significant difference was observed at 5 mm from the WL. BR sealer showed higher alkaline pH, rougher surface, lower water contact angle values, lower flowability, and higher solubility compared to CS. BR showed globular and needle-like crystalline microstructure, whilst CS had globular and flower-like crystalline microstructure up to 72 h. No statistical difference was found for the compressive strength between the two sealers. BR and CS showed no antibacterial effect against Enterococcus faecalis after 3 h, whilst both sealers showed antibacterial capacity after 24 and 72 h. BR demonstrated higher antibacterial activity after 24 h. In conclusion, the use of bioceramic sealers may play an important role in controlling bacterial growth. Moreover, CS may have superior filling ability and lower solubility than the BioRoot sealer due to its specific chemical composition and mixing method.

Micro-computed tomography evaluation of root canal filling quality with apical negative pressure

OBJECTIVES

The objective of the present study was to compare, using micro-computed tomography (micro-CT), the location and volume percentage of voids in root canals that were obturated with a premixed tricalcium silicate sealer and a single gutta-percha master cone, in the presence or absence of apical negative pressure.

METHODS

Twenty extracted human mandibular premolars were cleaned and shaped. The teeth were assigned to 2 groups (n = 10) according to the filling technique: apical negative pressure sealer application combined with the single-cone technique (NPS) or syringe-assisted sealer application combined with the single-cone technique (SS). Each specimen was scanned using micro-CT at 10 μm resolution. The percentages of voids were calculated from segmental regions of interest. Data were analysed using nonparametric statistical methods, with statistical significance pre-set at α = 0.05.

RESULTS

Significant difference was identified (p < 0.05) in the overall percentage of voids between the NPS group (0.33 %; interquartile range 0.25 %) and the SS group (6.29 %; interquartile range 5.57 %). In the NPS group, the percentages of voids in the coronal-third or middle-third of the canal space were statistically lower than that in apical-third (p < 0.0167, Bonferroni adjustment), with no significant difference between the former two groups. In the SS group, no significant difference in the percentages of voids was identified among the coronal-third, middle-third and apical-third of the canal space.

CONCLUSIONS

Apical negative pressure sealer application combined with the single-cone technique produces fewer voids in root canal fillings than the conventional single-cone technique.

CLINICAL SIGNIFICANCE

The apical negative pressure sealer application technique combined with single-cone filling constitutes a novel root canal obturation technique that improves the quality of root canal filling by minimising the volume of voids within the three-dimensional canal space.

Effect of ultrasonic cleaning on the bond strength of fiber posts in oval canals filled with a premixed bioceramic root canal sealer

Objective

This study aimed to evaluate the effect of ultrasonic cleaning of the intracanal post space on the bond strength of fiber posts in oval canals filled with a premixed bioceramic (Bio-C Sealer [BIOC]) root canal sealer.

Materials and Methods

Fifty premolars were endodontically prepared and divided into 5 groups (n = 10), based on the type of root canal filling material used and the post space cleaning protocol. A1: gutta-percha + AH Plus (AHP) and post space preparation with ultrasonic cleaning, A2: gutta-percha + BIOC and post space preparation with ultrasonic cleaning, B1: gutta-percha + AHP and post space preparation, B2: gutta-percha + BIOC and post space preparation, C: control group. Fiber posts were cemented with a self-adhesive luting material, and 1 mm thick slices were sectioned from the middle and cervical third to evaluate the remaining filling material microscopically. The samples were subjected to a push-out test to analyze the bond strength of the fiber post, and the results were analyzed with the Shapiro-Wilk, Bonferroni, Kruskal-Wallis, and Mann-Whitney tests (p < 0.05). Failure modes were evaluated using optical microscopy.

Results

The results showed that the fiber posts cemented in canals sealed with BIOC had lower bond strength than those sealed with AHP. The ultrasonic cleaning of the post space improved the bond strength of fiber posts in canals sealed with AHP, but not with BIOC.

Conclusions

BIOC decreased the bond strength of fiber posts in oval canals, regardless of ultrasonic cleaning.

Root canal obturation materials and filling techniques for primary teeth: In vitro evaluation in polymer-based prototyped incisors

BACKGROUND

Achieving a void-free root canal filling is a challenge in current clinical pulpectomy practice.

AIM

To compare filling effectiveness and internal voids of root filling materials and obturation techniques in resin-prototyped primary incisors by micro-CT.

DESIGN

Fifty prototypes were instrumented and randomly divided (n = 10) according to the filling materials (Vitapex^® , ZOE, Calcicur^® , Feapex, and Calen^® -ZO) and obturation technique: lentulo or pressure syringe (n = 5). The specimens were micro-CT scanned (pixel size = 7.83 μm) and reconstructed, and the total volume of filled canal (%FC) and internal voids (%IV) of the bulk filling material was calculated. Kruskal-Wallis and Mann-Whitney tests were used to detect differences and interactions among groups.

RESULTS

Calen^® -ZO, Vitapex^® , and ZOE showed similar %FC. Calcicur^® showed lower %FC compared with Calen^® -ZO, Vitapex^® , and ZOE (P < .05) but similar to Feapex. No statistically significant differences in %FC between lentulo or pressure syringe were disclosed. Regarding %IV, Vitapex^® , and Calen^® -ZO performed better with syringe, although Calcicur^® was better with lentulo. The number of voids in the obturation bulk was similar among materials, but always lower (P < .05) in syringe filled specimens.

CONCLUSION

Vitapex^® , Calen^® -ZO, and ZOE outperformed Calcicur^® and Feapex in %FC and if the syringe technique is used, %IV of the obturation bulk and presence of defects was lower.