The Impact of Different Access Cavity Designs on the Retreatment Procedure of Single Oval Canals Using Reciprocating File Systems: An Ex-Vivo Study

The aim of the present study was to evaluate the adaptation of a calcium silicate bioceramic (BC) sealer with either BC or conventional gutta-percha compared with that of AH Plus sealer in different root canal sections. Seventy-two extracted mandibular premolars were divided randomly into six groups. After standardised chemomechanical preparation, four groups were obturated with the BC sealer and BC gutta-percha or conventional gutta-percha, and the other two groups were obturated with AH Plus sealer and conventional gutta-percha either in lateral compaction or in a single cone technique. Each root was sectioned into three sections. An impression was made from each section, and replicas were then made for scanning electron microscopy (SEM) analysis. Areas and interfacial gaps were identified using image analysis software. In addition to descriptive and explorative data analyses, linear regression analysis was performed. All specimens had measurable interfacial gaps. Significantly fewer gaps were found between conventional gutta-percha and sealer compared to those observed when using the BC gutta-percha (p<0.001). However, minor interfacial gaps between sealer and dentin were observed with the BC sealer (p=0.04). The technique of obturation in different root canal sections did not significantly affect the sealer adaptability. The type of gutta-percha as well as the sealer had a noticeable impact on the adaptability. Different obturation techniques will result in similar outcomes. However, within the limitations of the study, there seems to be no advantage in using the BC gutta-percha.

Aim: This study aimed to compare the effects of different endodontic access cavity designs on canal transportation (CT) and centering ability (CA) using the bondent platinum file system on mandibular molars, utilizing cone-beam computed tomography (CBCT). Methods: Thirty extracted human permanent mandibular molars which fulfilled the inclusion criteria were divided into three groups, Group 1 (TEC): Traditional endodontic access cavity (control group), Group 2 (CEC): Conservative endodontic access cavity, and Group 3 (TrEC): Truss endodontic access cavity. The teeth were scanned using CBCT initially followed by random allocation into three groups. Root canals were prepared using Bondent platinum file system in mesiobuccal and mesiolingual canals using #25.06 file and in distal canal #30.06 file. Postpreparation, CBCT scans to assess CT and CA at 3 mm, 5 mm, and 7 mm from the apex. Data analysis was performed using a one-way analysis of variance and Tukey’s post hoc test. Results: Significant differences (P &lt; 0.01) in mean CT and CA were observed between Group 1 (TEC) and Groups 2 (CEC) and 3 (TrEC). Dentin removal was highest at 3 mm, followed by 5 mm and 7 mm. The distal canal showed the greatest dentin loss compared to other canals. Conclusion: Minimal access cavity designs (CEC and TrEC) demonstrated less CT and improved CA compared to the traditional access cavity design (TEC). Study limitations acknowledged that conservative access cavity designs result in less deviation (CT) and better centering of the prepared canals compared to the traditional approach (TEC). These results imply the potential benefits of adopting less invasive access cavity designs in endodontic practice to enhance treatment outcomes.

The impact of adding silver nanoparticles (AgNPs) to bioceramic (BC) sealer on their ability to penetrate dentinal tubules is still unknown. Thus, this confocal laser scanning microscopic (CLSM) study aimed to assess the extent of dentinal tubule penetration of BC sealer (TotalFill® Hiflow BC Sealer™, FKG, Switzerland) with and without AgNPs using the single-cone (SC) technique and the continuous-wave condensation (CWC) technique. AgNPs alone as well as in a mixture with the BC sealer were characterized using scanning electron microscopy and transmission electron microscopy. Single-rooted extracted human teeth (N = 100) were selected and prepared, and then divided into four groups (n = 25). Group 1 (BC/SC): BC sealer obturated with the SC technique. Group 2 (BC+AgNPs/SC): BC sealer with AgNPs obturated with the SC technique. Group 3 (BC/CWC): BC Sealer obturated with the CWC technique. Group 4 (BC+AgNPs/CWC): BC Sealer with AgNPs obturated with the CWC technique. After 2 weeks, roots were horizontally sectioned to obtain 1 mm thick dentin slices that were evaluated with CLSM. Sealer dentinal tubule penetration area and the maximum depth of penetration were measured. Data were analyzed with one-way ANOVA and the Tukey multiple comparison tests (p ≤ 0.05). The characterization process demonstrated a spherical-shaped nanoparticles without obvious agglomeration. The results showed that Group 2 (BC+AgNPs/SC) significantly demonstrated the highest mean tubular penetration depth, while group 3 (BC/CWC) had the lowest mean depth. Group 2 (BC+AgNPs/SC) exhibited the significantly highest mean value for the total area of penetration. However, groups 1 (BC/SC) and 3 (BC/CWC) exhibited the lowest mean value of total penetration area, with no statistically significant difference. The integration of AgNPs with BC sealer markedly enhanced penetration into dentinal tubules. The SC technique demonstrated superior penetration relative to the CWC technique.

To evaluate the influence of ultraconservative endodontic access cavities (UEC) on gaps and void formation in resin composite restorations in extracted two-rooted maxillary premolars after root canal treatment. Traditional endodontic access cavities (TEC) were used as a reference for comparison. Two-rooted maxillary premolars were scanned in a micro-computed tomographic (micro-CT) device, matched based on similar anatomical features and allocated into two groups (n=10) according to the design of the access cavity: TEC or UEC. Teeth were mounted on a mannequin head and a single operator performed the treatment, including endodontic access cavity preparation, root canal detection, preparation, filling and restoration procedures, under magnification. For restorative procedure, a bulk fill flowable layer was applied initially followed by an overlaying of regular composite. After restoration procedures, a new micro-CT scan was performed to check the quality of the coronal restoration by analysing the percentage volume of empty spaces present in the tooth-restoration interface (gaps) and inside the restoration (voids). Data were analysed statistically using Shapiro-Wilk and Student's t tests with a significance level of 5%. All specimens had gaps and voids. There were significant differences between the access cavity designs regarding the formation of voids with significantly more voids associated with the UEC (P<0.05). Gap formation did not differ between groups (P>0.05). The access cavity design used during root canal treatment interfered with the adaptation of the restorative material. The minimally invasive access cavity design was associated with a significantly greater number of voids within restorations.

Does the Orifice-directed Dentin Conservation Access Design Debride Pulp Chamber and Mesial Root Canal Systems of Mandibular Molars Similar to a Traditional Access Design?

Introduction: The aim of the study was to evaluate the bacterial leakage of four different bioceramic root canal sealers and to compare it to the conventional epoxy resin-based sealer. Materials and Methods: The study sample consisted of 94 single-rooted human teeth with one round root canal, which were instrumented and randomly distributed into five experimental groups according to the root canal sealer: Group 1: TotalFill bioceramic sealer; Group 2: BioRoot root canal sealer; Group 3: mineral trioxide Aggregate (MTA) Fillapex; Group 4: MTA Plus; Group 5: epoxy resin-based sealer AH Plus and positive and negative control group. The prepared samples were fixed in a model designed for the Enterococcus faecalis leakage evaluation and were sterilized in plasma. The bacterial penetration through the filled root canals was checked by the color change in the lower tube during 60 days. The scanning electron microscopy was used to check the bond between the sealer and the dentine wall. Data were statistically analyzed. Results: Total Fill bioceramic sealer (BCS) group presented significantly lower number of samples that leaked (14.2%) compared to the AH Plus group (78.6%) (P = 0.002) and MTA Plus group (50%) (P = 0.046). There was no statistically significant difference between other groups (P > 0.05). Conclusion: The TotalFill BCS root canal sealer provided better sealing ability compared to the AH Plus and the MTA Plus sealers.

Background: It has been established that several filling techniques can affect apical leakage, which is responsible for 59% of endodontic failures. The primary goal of endodontic therapy is to create a tight seal that aids in repairing the periapical tissues, prevents apical periodontitis, and shields against root canal infection. The study aims to compare the apical sealing ability of epoxy resin based sealer (AH plus), which is an epoxy-resin-based root canal sealer, GuttaFlow 2, which is a silicone-based root canal sealer, GuttaFlow bioseal is a bioactive glass-based root canal sealer, TotalFill HiFlow bioceramic (BC) sealer is a silicate-based root canal sealer (bioceramic sealer) using a single cone technique by spectrophotometric analysis. Methods: This study chose 64 maxillary first molars with a straight palatal root. Following palatal roots sectioning to 11 mm from the root apex, the canals were instrumented up to size X4 using Protaper Next. They were separated into four experimental groups (n = 15) per each group based on the kind of sealer utilized, Group I: AH plus, Group II: GuttaFlow 2, Group III: GuttaFlow bioseal, Group IV: TotalFill BC HiFlow, and two control groups (n =2 for each). After completing obturation, the dye extraction technique was used to evaluate apical leakage. A spectrophotometer was used to measure the optical density of the solution after all the dyes were liberated from the interfacial regions. Result: A statistically non-significant difference between the investigated root canal sealers in apical microleakage P &gt; 0.05 was noted. The highest mean values were observed in group IV (0.08046), group I(0.07731), and group II(0.06209), while the lowest mean value in group III (0.05719) Conclusions: All types of sealers used in this investigation showed various amounts of microleakage. None of the sealants could completely close the apical foramen to provide a fluid-tight seal.

In recent years, new endodontic access techniques have been proposed with the aim of preserving as much dental tissue as possible for subsequent prosthetic rehabilitation. It has indeed been demonstrated that the success of this therapy is essential and dependent on the proper execution of endodontic cavity access. The main objective is to provide a comprehensive and up-to-date overview of the new access techniques in endodontics in order to guide clinical practice toward a more precise and qualitative approach. As of today, there is still no universally standardized and recognized taxonomy for the different access cavity designs described in the literature. It has been observed that there are various nomenclatures in the literature. The cavity access designs described mainly in the literature can be categorized into six groups: Traditional Access Cavity (TradAC), Conservative Access Cavity (ConsAC), Ultra-Conservative Access Cavity (UltraAC), Truss Access Cavity (TrussAC), Caries-Guided Access Cavity (CariesAC), and Restoration-Guided Access Cavity (RestoAC). The drafting of this narrative review followed the indications of the SANRA (Scale for the Assessment of Narrative Review Articles). A search for scientific articles was conducted on the PubMed and SCOPUS databases, using the following search query: ((truss) OR (conservative) OR (ninja) OR (traditional)) AND access AND endodontic. The initial search yielded a total of 941 articles. After removing duplicates using EndNote X8 software, the number of articles decreased to 785. By applying the inclusion and exclusion criteria, a total of 64 articles were obtained. Among these, 20 articles were finally selected for the purposes of this review, 11 literature reviews and 9 ex-vivo studies. Studies on fracture resistance have yielded heterogeneous results. For anterior teeth, studies do not find a significant relationship between different endodontic access cavities and fracture resistance. However, in the posterior sector, there is more discrepancy and many positive results for minimally invasive access cavities seem to relate to molars. Therefore, it can be concluded that the evidence supporting the influence of endodontic preparations on dental fracture resistance is still limited. Research on new endodontic access techniques holds significant clinical relevance in contemporary endodontics. The evolution of dental technologies, including cone beam computed tomography (CBCT) and computer-guided cavity preparation, has ushered in the era of minimally invasive endodontics. This shift aims to enhance the precision and quality of endodontic treatments while preserving maximum healthy dental tissue for subsequent prosthetic rehabilitation. The success of endodontic therapy is closely tied to the proper execution of access to the endodontium, influencing all phases of endodontic treatment and playing a role in determining fracture resistance for subsequent rehabilitation phases. The dichotomy between traditional and minimally invasive approaches has spurred clinical investigations. Specifically, within the scientific community, doubts have been raised about the potential limitations of minimally invasive access cavities. Concerns include their impact on canal orifice localization and raise questions about their influence on the overall success of endodontic treatment. This review holds clinical significance as it sheds light on the evolving landscape of endodontic access techniques, analyzing the anatomical trajectory, carefully examines the transition to minimally invasive approaches, and critically assesses existing scientific evidence and concerns surrounding these developments, contributing to an informed decision-making process in clinical practice.

ObjectiveThis study aims to assess the efficacy of bioceramic (BC) sealer when applied using the single cone technique (SCT), in comparison to AH Plus sealer applied with the cold lateral condensation technique (LCT), concerning their impact on the healing of large-sized periapical lesions in both untreated and retreatment cases.Materials and methodsA randomized controlled trial was conducted on 41 patients who had 60 permanent teeth in the maxillary incisors that were accompanied by large-sized periapical lesions. The included teeth were radiographed with cone beam computed tomography (CBCT) images and divided equally into two groups according to the endodontic treatment statute (30 untreated previous cases and 30 retreated cases). Subsequently, teeth received uniform preparation, irrigation, and dressing procedures. Then each group was divided equally according to the used sealer (15 teeth obturated using AH plus sealer with LCT and 15 teeth obturated using BC sealer with SCT). All cases were followed up after 6 and 12 months with CBCT images. Subsequently, the change in periapical lesion diameter (PLD) was observed as an indicator to determine the treatment outcome score. One-way ANOVA and Mann–Whitney U test were used to analyze the PLD changing and scoring the treatment outcome during the follow-up periods. The significance level was set at α = 0.05.ResultsThere were no statistically significant differences between untreated and retreatment cases neither using AH plus sealer with LCT nor BC sealer with SCT regarding changes in PLD in the follow-up periods. Moreover, there were no significant differences between groups regarding treatment outcome scores in the follow-up periods. All groups showed a high success rate.ConclusionsSuccessful treatment was achieved for untreated or retreatment maxillary incisor cases accompanied by large-sized periapical lesions using either BC sealer with the SCT or AH Plus sealer with LCT with a similar high success rate up to 12 months follow-up period.

Background: Mineral trioxide aggregate (MTA) is the most widely used material in endodontics, and recently, it has been used as an endodontic sealer. Bioceramic (BC) is a newly developed material based on calcium silicate, which is already used as a biocompatible root canal obturation material to overcome the weakness of MTA. However, there have been no studies comparing the materials used to seal the root canal. Objective: This study aimed to determine the apical leakage differences between BC and MTA sealers with BC-coated gutta-percha (GP) and conventional GP. Methods: In total, 40 mandibular premolars were cut coronally to 14 mm of working length. All samples were randomized and sorted into four groups: BC sealer with BC-coated GP, bioceramic sealer with conventional GP, MTA sealer with BC-coated GP, and MTA sealer with conventional GP. The samples were stored in an incubator, and nail varnish was applied to all root surfaces except for a 1 mm area from the apex. The samples were also soaked in methylene blue for 72 h before undergoing diaphanization. A stereomicroscope was used to measure the methylene blue penetration. All data were analyzed using analysis of variance. Results: There were significant differences in apical leakage between the BC and MTA sealers (P < 0.05). Conclusion: The BC sealer prevented apical leakage better than MTA. The BC-coated GP had better results than the conventional GP, but the differences were not significant, indicating that the choice of sealer is more important in preventing the apical leakage.

Effective sealing of root canal systems is paramount in achieving favorable and enduring prognosis of root canal treatments (RCTs). Root canal sealers play a pivotal role in sealing the canal system. To date, there is a scarcity of clinical research investigating the implications and long-term performance of bioceramic (BC) sealers. This study aims to compare the treatment outcome of resin-based (RB) and BC root canal sealers. Retrospective data comparing clinical outcomes of 248 endodontically treated teeth was performed utilizing dental records and radiographic assessments. Clinical outcome of the RCTs using both types of sealers were measured by percentages of success rates. Chi square statistical test was used to analyze data at 0.01 and level of significance via SPSS software. Success rate of RCTs was not influenced by patient’s age, gender, tooth type and number of visits. There were no significant differences in the success rate amongst treatment types, obturation techniques, quality of restoration and the sealer type. BC and RB sealers revealed comparable clinical and radiographic outcomes with high success rates. The choice between BC and RB sealers should be guided by case-specific factors, including tooth’s anatomical considerations, patient’s dental health status, obturation techniques and clinician’s skills.

The present study evaluated the retreatability of canals obturated using AH Plus sealer and Bioceramic (BC) sealers, employing Cone beam computed tomography (CBCT) and Scanning Electron Microscope (SEM). A group of 90 extracted premolars was classified into two main categories based on whether they were sealed with AH Plus or BC Sealer. Each of these categories was then divided into two subcategories according to the retreatment technique applied. CBCT and SEM were used to assess the residual filling material within the canals. The findings showed that there was no marked statistical variation in the retreatment success of canals sealed with BC and AH Plus sealers. The diode laser was the most effective modality for eliminating root canal filling materials in the least amount of time. None of the retreatment modalities used removed the obturating material completely.

Background: The access cavity is a critical stage in root canal therapy and it may influence the subsequent steps of the treatment. The new minimally invasive endodontic access cavity preparation concept aims to preserve sound tooth structure by conserving as much intact dentine as possible including the pulp chamber's roof, to keep the teeth from fracturing during and after endodontic treatment. While there is great interest in such access opening designs in numerous publications, still there is a lack of scientific evidence to support the application of such modern access cavity designs in clinical practice. This review aims to critically examine the literature on minimal access cavity preparations, explain the effect of minimally invasive access cavity designs on various aspects of root canal treatment, and identify areas where additional research is required. Data: An electronic search for English-language articles was performed using the following databases: Google Scholar, PubMed, and Research Gate. The following keywords were used: "minimally invasive access cavity", "conservative endodontic cavity ", and "classification of access cavity". Study selection: 64 papers that were the most relevant to the topics in this review were selected between 1969 to 26 February 2022. Conclusions: Minimally invasive access cavities can be classified into conservative, ultraconservative, truss access, caries and restorative-driven cavities. There is a deficiency of proof that a minimally invasive access cavity maintains the resistance to fracture of endodontically treated teeth greater than traditional access cavities. There was no difference in the percentage of untouched walls and debris removal in teeth with conservative vs traditional access cavities, however, truss and ultraconservative access cavities resulted in poor irrigation efficacy compared to traditional ones. Also, the lower cyclic fatigue resistance of rotary instruments and root canal obturation with voids were associated with minimally invasive access cavities. The studies about minimally invasive access cavities still have a wide range of methodological disadvantages or register unsatisfactory or inconclusive results. Therefore, further research on this topic is needed especially with the everyday advancement of techniques and armamentarium used in endodontics.

Aims:The study aimed to evaluate and compare the efficacy of xylene in dissolving newer bioceramic sealers versus an epoxy resin-based sealer during endodontic retreatment.Subjects and Methods:Comparing AH Plus to gutta-percha (GP) and CeraSeal (Meta Biomed), Prashanti Bioceramic Sealer, and MTA-Fillapex (Angelus), a total of 72 (n = 18) extracted human permanent teeth with a single root and a single canal were prepared to size F3 and obturated. The ProTaper Universal Retreatment technology was then used to retreat the canals. The percentage volume of remaining filling material was determined by measuring the amount of residual material following retreatment using cone-beam computed tomography.Statistical analysis used:The Tukey’s post hoc test and one-way ANOVA were used to analyze the data.Results:Dissolving sealers with xylene showed varying degrees of efficiency. The results showed statistically significant difference between resin sealer and bioceramic sealers but no statistical difference among bioceramic sealers in the amount of residual after retreatment (P < 0.05). MTA Fillapex had the greatest retrievability, whereas AH Plus had the lowest.Conclusions:Bioceramic sealers were more easily dissolved by xylene than epoxy resin-based sealers. The variability among bioceramic sealers suggests that their composition significantly influences their retreatability to consider in endodontic retreatment planning.

Aim: The aim of this study was to evaluate the efficacy of self-adjusting files (SAFs) and the E18 isthmus ultrasonic tip as supplementary instruments following the use of neoendo retreatment files for removing gutta-percha (GP) and bioceramic (BC) sealer during the retreatment of oval canals using cone-beam computed tomography (CBCT). Methods: Forty-five extracted mandibular premolars with oval canals were prepared to a length of 16 mm after decoronation. Canals were prepared with the Neoendo flex rotary system up to size #40, followed by obturation with GP and BC sealer (Ceraseal) by cold lateral compaction. CBCT scans of all the samples were taken to analyze the volume of the filling material. Retreatment was then performed in all the samples with the neoendo retreatment file system. The samples were divided into three groups (n = 15) based on the supplementary instruments to be used in removing the remaining filling material as follows: GROUP I: no supplementary instrument, GROUP II: SAF, and GROUP III: E18 Isthmus Ultrasonic tip. CBCT scans were taken after the use of supplementary instruments, and the volume of residual filling material was measured. Results: GROUP II (SAF) exhibited the lowest mean percentage of remaining filling material, followed by GROUP III (E18 ultrasonic tip) and GROUP I (no supplementary instrument). The differences in the mean percentage of residual filling material among the three groups were statistically significant (P &lt; 0.001). Conclusion: None of the supplementary instruments eliminated GP and BC sealer completely from the canals. However, the use of supplementary instruments enhanced the removal of filling material following the primary retreatment. SAF proved to be more effective than the E18 isthmus ultrasonic tip in removing GP and BC sealer during the retreatment of oval canals.