Traditional Access Cavity Research Articles

Three-dimensional finite element analysis of the impact of access cavity preparation on first molar fracture resistance: A scoping review.

Access cavity preparation represents the initial step in root canal treatment. Minimally invasive approaches have gained increasing attention and involve advancements in the traditional access cavity preparation. Simultaneously, the development of three-dimensional finite element analysis (3D-FEA) has provided a theoretical foundation for evaluating the merits and drawbacks of various access cavity preparations. Studies using static loading 3D-FEA have suggested that conservative access cavity preparation reduces the concentration of stress in the cervical region, thereby strengthening fracture resistance. However, the lack of support from clinical data raises concerns about the validity of this suggestion. Conversely, studies involving cyclic loading 3D-FEA and dynamic loading 3D-FEA have challenged the prevailing perspectives by taking into account additional factors such as filling materials, thus providing a more comprehensive understanding of the impact of access cavity preparation on fracture resistance. Existing research lacks a comprehensive comparison of the different 3D-FEA methods, and this review fills this gap by providing a systematic assessment of different 3D-FEA methods and their applications in access cavity preparation.

Comparative evaluation of different endodontic access cavity designs on canal transportation and centering ability using bondent platinum file system on mandibular molar – An in vitro cone-beam computed tomography study

ABSTRACT 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). Methodology: 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 < 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.

Comparative Evaluation of Three Access Cavity Preparation Techniques on Root Canal Instrumentation Using Micro-CT: An In Vitro Study.

Background Access cavity preparation is a crucial step in nonsurgical root canal treatment. Recent advancements in access cavity designs focus on preserving maximum tooth structure while ensuring sufficient access to canal orifices for effective cleaning and shaping, resulting in minimally invasive procedures. However, there is limited information on the impact of three-dimensional (3D)-guided access cavity preparation in molars. A literature review found no prior studies comparing the effects of various access cavity preparation techniques on apical transportation, untouched surfaces, and debris formation within the canal. Objective The objective of this study is to compare and evaluate the effects of three different access cavity techniques on apical transportation, untouched surfaces, and debris formation within the root canal. Material and methods Thirty extracted permanent mandibular first molars were selected and randomly assigned to three groups for this study: Group I received 3D-printed static guided cavity preparation, Group II underwent conservative access cavity preparation, and Group III was subjected to traditional access cavity (TAC) preparation. The mesial canals in all samples were cleaned and shaped using TruNatomy files. Preoperative and postoperative micro-CT imaging was performed on each sample to assess the effects of the different access cavity preparation techniques on apical transportation, untouched surfaces, and debris formation within the root canal. Results The study found that Group I, which used 3D-printed static guided cavity preparation, exhibited significantly less apical transportation compared to Groups II and III, with mean differences of -0.1677 and -0.2079, respectively. Debris accumulation was similar across all groups, with mean values of 0.928 ± 0.824 for Group I, 0.751 ± 0.495 for Group II, and 0.938 ± 0.681 for Group III, indicating no significant impact of cavity preparation type on debris levels. For untouched canal surfaces, Group III (TAC preparation) had the fewest untouched surfaces, with mean differences of 3.0380 and 3.9020 compared to Groups II and I, respectively. Conclusions While TAC preparation reduces substantial tooth structure, it shows higher instrumentation efficacy and better cleaning of the root canal system. However, in complex cases where tooth structure preservation is crucial, guided access cavity preparation provides an effective balance between structural conservation and adequate canal access. This approach offers a tailored solution, optimizing treatment outcomes based on the specific clinical scenario.

Digital precision meets dentin preservation: PriciGuide™ system for guided access opening

Traumatic injuries to maxillary central incisors often necessitate root canal treatment (RCT). However, traditional access cavity preparation can remove significant dentin, compromising tooth strength and long-term prognosis. This article explores the use of the PriciGuide™ system for minimally invasive access cavity preparation in such cases. PriciGuide™ system is a novel, patented system that utilizes a sleeveless guide technique to enhance accuracy and control during access procedures. This article presents a clinical case demonstrating the application of PriciGuide™ system for access cavity preparation in traumatized necrotic maxillary central incisors. The focus is on preserving dentin while achieving optimal access for successful RCT. By showcasing the effectiveness of PriciGuide™ system in this case, this article contributes to the growing body of evidence supporting its role in minimally invasive endodontics. The approach presented has the potential to improve long-term outcomes for patients with not only traumatized necrotic maxillary central incisors but also in teeth having prosthesis that requires RCT and in teeth with calcifications.

Influence of endodontic access cavity design on mechanical properties of a first mandibular premolar tooth: a finite element analysis study

ObjectivesThis study aimed to investigate the influence of access cavity designs on the mechanical properties of a single-rooted mandibular first premolar tooth under various static loads using a finite element analysis.Materials and methods3-dimensional FEA designs were modeled according to the access cavity designs: an intact tooth (control), traditional access cavity (TEC-I), traditional access cavity with Class-II mesio-occlusal cavity design (TEC-II), conservative access cavity (CEC), ninja access cavity (NEC), caries-driven access cavity (Cd-EC), buccal access cavity (BEC) and bucco-occlusal access cavity (BOEC). After the simulated access cavity preparations, root canal treatment was simulated and three different static loads which mimicked oblique and vertical mastication forces were applied to the models. The stress distribution and maximum Von Misses stress values were recorded. The maximum stress values were obtained on both enamel and dentin under multi-point vertical loads.ResultsThe maximum stress values were obtained on both enamel and dentin under multi-point vertical loads. Under all load types, the minimum stress distribution was observed in the control group, followed by CEC, NEC and BEC designs. The highest stress concentration was detected in Cd-EC and TEC-II designs. Under single-point vertical loading, the stress was mostly concentrated in the lingual PCD area, while under multi-point vertical loading, the entire root surface was stress-loaded except for the lingual apical third of the root.ConclusionPreserving tooth tissue by simulating CEC, NEC and BEC access cavities increased the load capacity of a single-rooted mandibular first premolar following simulated endodontic treatment.

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

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

Do Ultraconservative Access Cavities Hinder Endodontic Reintervention in Mandibular Incisors? A Laboratory Investigation.

This study assessed the influence of the type of endodontic access cavity on endodontic reintervention. Twenty mandibular central incisors were distributed into two groups (n = 10): TradAC group-traditional access cavities and UltraAC.Inc group-ultraconservative access cavities. After endodontic access, the root canals were prepared and obturated by the single cone technique. The filling material was removed with the Reciproc R25 instrument, followed by reinstrumentation with the R40 instrument. Images acquisition of each root canal hemisection was performed in a stereomicroscope to quantify the amount of remaining filling material. The amount of remaining filling material attached to the root canal walls was expressed in square millimeter (mm2). Data were statistically analyzed (one-way ANOVA and post hoc Student's t-tests). There was no statistically significant difference between TradAC and UltraAC.Inc groups (p > 0.05). None of the tested endodontics' access showed root canal walls completely free of filling material. Ultraconservative access cavities in mandibular incisors had no negative impact on the filling material removal.

Reciprocation and rotation nickel-titanium file systems’ cyclic fatigue and centering ability in premolars accessed by ultraconservative and traditional access cavities: An in vitro study

Introduction: With the importance of restricted access cavities, this study aimed to compare the cyclic fatigue and the centering ability of TruNatomy rotary file versus R-motion reciprocating file systems in premolars accessed by traditional versus ultraconservative access cavity preparations. Materials and Methods: Forty extracted intact maxillary first premolars were divided into two groups (n = 20/group) according to the access cavity design (traditional or ultraconservative). Each group was then subdivided according to the type of file used for instrumentation (TruNatomy [26/0.04] or R-motion [30/0.04] [n = 10 teeth/subgroup]). Cone-beam computed tomography (CBCT) scans were obtained for all the teeth before and after instrumentation. The teeth were accessed and instrumented by three in-and-out pecking motions repeated two times until the instrument reached the working length. Every instrument was only used to prepare one canal. For cyclic fatigue assessment, the used files, in addition to 10 brand-new TruNatomy and R-motion files that were used as control groups, were tested in stainless-steel artificial canals, and the time to fracture was used to determine the number of cycles to fracture (NCF). After obtaining and analyzing the before and after instrumentation CBCT images, the centering ability of the buccal roots was calculated at 3, 5, and 7 mm from the apex. Data were statistically analyzed. Results: There were no differences in NCF and centering ability of each file in both access cavities (P &gt; 0.05). There were higher NCF values of the R-motion file compared to the TruNatomy file (P &lt; 0.05). The R-motion file showed significantly higher centering than the TruNatomy file in the traditional access cavity at the 3 and 5 mm levels and the 3 mm level in the ultraconservative access cavity (P &lt; 0.05). Conclusion: The R-motion file had significantly higher cyclic fatigue resistance and centering ability than the TruNatomy file. The ultraconservative access cavity had no unfavorable influence on the cyclic fatigue resistance and the centering ability of R-motion and TruNatomy files.

Impact of Access Cavity Design on Fracture Resistance of Endodontically Treated Maxillary First Premolar: In Vitro.

This study was designed to investigate the impact of access cavity designs on fracture resistance of endodontically treated maxillary first premolars. The study sample consisted of 72 intact maxillary first premolars, randomly divided into six groups (n = 12). A standardized proximal cavity preparation was prepared for all samples using standard bur. Groups I: control group with only standard proximal cavity and no endodontic access, group II: Truss access cavity, group III: Separated access to buccal and palatal canals without removal of dentine in between, group IV: Access to buccal and palatal canals with removal of dentine in between, group V: Traditional access cavity, group VI: Mesio-occlusal-distal cavity (MOD). For groups I and VI, only composite restoration was used to restore the proximal cavity, while for groups II- V, the access was prepared and endodontic treatment was performed on all teeth, then composite restoration was placed. The root canals were instrumented using nickel-titanium files, irrigated with sodium hypochlorite, and filled with AH plus sealer and gutta-percha using warm vertical condensation. All samples were then placed in an acrylic mold and underwent thermal aging for 10,000 cycles between 5 and 55°C. The samples were fixed in a universal testing machine with the long axis of the roots positioned at 20° to a load applied at a crosshead speed of 1 mm/min using a stainless steel semi-spherical indenter (Ø = 3 mm) until fracture occurred to determine the fracture resistance force in Newton. The normality test (Shapiro-Wilk) showed that data are normally distributed. Group II exhibited the highest mean fracture resistance, and group VI was the least likely to resist the fracture. No statistically significant differences between tested groups (p-value = 0.237). The MOD group showed a more unfavorable mode of fracture compared to other groups. No significant difference in fracture resistance between conservative and traditional access cavities. The missing marginal ridges, such as in MOD cavities played an important role in decreasing the fracture resistance of endodontically treated teeth.

Influence of Cavity Designs on Fracture Resistance: Analysis of the Role of Different Access Techniques to the Endodontic Cavity in the Onset of Fractures: Narrative Review.

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.

The Effect of the Conservative versus the Traditional Access cavity on microhardness of Nickel Titanium Rotary Files

The Effect of the Conservative versus the Traditional Access cavity on microhardness of Nickel Titanium Rotary Files

The Effect of Restoration of Endodontically Treated Teeth with Different Restorations in Both Modern and Traditional Access Cavity Preparations

The Effect of Restoration of Endodontically Treated Teeth with Different Restorations in Both Modern and Traditional Access Cavity Preparations

The efficacy of a novel SWEEPS laser-activated irrigation compared to ultrasonic activation in the removal of pulp tissue from an isthmus area in the apical third of the root canal.

This study aimed to evaluate the efficacy of Shock Wave Enhanced Emission Photoacoustic Streaming (SWEEPS) in the removal of remaining pulp tissue from the root canal isthmus area in lower molars and compare it with ultrasonically activated irrigation (UAI) and conventional needle irrigation (NI). Forty-one lower molars with isthmuses between mesial canals were included in the study. The teeth were randomly distributed into experimental groups (n = 12/each) based on the final irrigation protocol (SWEEPS, UAI, or NI) and a control group (C) (n = 5). The traditional access cavity of the mesial part of each tooth was made in all samples. The mesial root canals in the experimental groups were instrumented with a Wave One Gold Primary (25/.07) file using 3% sodium hypochlorite (NaOCl) while the distal canal served as a control for the presence of pulp tissue. No treatment was performed in the C group. Sections from the isthmus region were processed for histopathology to measure the remaining pulp tissue (RPT). The results were analyzed using analysis of variance and the Kruskal-Wallis test (α = 0.05). There were no significant differences in the relative surface area of root canals and isthmus among the groups (p > 0.05). Samples in the SWEEPS group had significantly less RPT than UAI, NI, and C (p = 0.003, 0.014, 0.003, respectively). There were no significant differences between the UAI and NI (p = 0.583). SWEEPS was the most efficient in debridement of the root canal isthmus area. UAI and NI showed similar but lower efficiency.

The Effect of Traditional and Ultraconservative Access Cavities On the Increase in Surface Area of Root Canal After Instrumentation: An in Vitro Study

Introduction: In this study, we aimed to evaluate the impact of ultraconservative and traditional endodontic access cavities on the total percentage increase in the surface area of root canals. Methods: Endodontic instrumentation was performed on 30 simulated maxillary first premolars with two roots using traditional and ultraconservative access cavities via ProTaper Next rotary files. The pre- and postinstrumentation photographs of the root canals were analyzed blindly using Fiji software to determine the percentage increase in surface area. Results: A significant increase in the surface area of the root canal was observed with an ultraconservative endodontic access cavity compared to a traditional access cavity. The difference between the palatal and buccal roots was not significant, but there was a significant difference among the coronal, middle, and apical thirds of the root canal. Conclusion: Ultraconservative access cavities have a significant impact on the increase in surface area of the root canal after instrumentation.

Minimally invasive access cavities in endodontics

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.

Effect of Traditional and Conservative Endodontic Access Cavities on Instrumentation Efficacy of Two Different Ni–Ti Systems: A Micro-CT Study

This study aims to compare the shaping efficiency of the nickel–titanium instrument systems, One Reci and ProTaper Ultimate, using micro-CT (micro-computed tomography) in traditional and conservative endodontic access cavities. The experimental groups were formed according to the type of access cavity and Ni–Ti file system to be used. Sixty mandibular molar teeth were randomly divided into two main groups, the conservative access cavity (CAC) group and the traditional access cavity (TAC) group, and randomly divided into two subgroups according to the file system. The groups were compared with a two-way ANOVA analysis in terms of volume change, surface area, non-instrumented area transportation, and thickness of the dentin in the danger zone area after root canal preparation. The groups showed no statistically significant differences in terms of volume change, surface area, or the thickness of the dentin in the danger zone area after root canal preparation (p &gt; 0.05). However, in the percentage of non-instrumented areas post-instrumentation between groups, the percentage of non-instrumented areas was statistically higher in specimens with CAC compared to TAC (p &lt; 0.05). Canal transportation was higher in CAC at all distances from the apical region (p &lt; 0.05). Within the limitations of this study, CAC can also be used with some precautions as an alternative to TAC.

Which endodontic access cavity is best? A literature review.

The preparation of an access cavity is the first part of endodontic treatment and is a key stage in the healing of both periapical and pulpal infections. It should allow endodontists to remove obstructions in the pulp chamber, locate all canal orifices and clean the entire root canal system with minimum coronal tooth structure removed. This has been done traditionally through establishing straight line access. The development of minimally invasive endodontics aimed to preserve as much of the natural tooth structure as possible, particularly dentine, while undertaking root canal treatment, resulting in the development of other access cavity preparations. This includes conservative, ultra conservative (ninja), truss, guided access, caries-orientated and restorative access cavities. These access cavity preparations also gained popularity due to increased magnification and enhanced lighting, allowing practitioners to visualise the pulpal space in greater detail throughout treatment.Our current recommendation is to conduct access cavities traditionally rather than conservatively. Ideally, conservative access cavities need magnification, which might not be available for all clinicians. With traditional access cavity, the procedure takes less time and it is more predictable to locate the canal orifices, deliver irrigation effectively, avoid iatrogenic damage with biomechanical preparation and achieve better obturation.

Assessment of minimally invasive file systems on resistance to fracture using traditional and contracted access cavity designs in the maxillary first and second molars.

The objective of the study was to evaluate the effect of access cavity design on fracture resistance of the extracted maxillary first and second molars prepared with three minimally invasive files. One hundred and twelve extracted human maxillary molars were selected for the study and divided randomly into three groups according to different minimally invasive files used (self-adjusting files [SAF], XP-endo Shaper [XP], and 4 V-Taper 2H [VT]) and one control group (CG). All experimental groups were subdivided into two subgroups, i.e., conservative access cavity (CAC) and traditional access cavity (TAC). All the canals in different experimental groups were enlarged up to apical size 30. The data were analyzed using the analysis of variance and Post hoc Tukey tests (P < 0.05). The highest mean fracture resistance of teeth with CAC was of the CG (1399.957), followed by teeth with CAC instrumented by SAF (1378.314) and XP-endo Shaper (1202.929). The least value was of the V-Taper file system (937.157). Furthermore, the highest mean fracture resistance value of teeth with TAC was of the CG (1143.171), followed by teeth with TAC instrumented by SAF (1150.607) and then XP-endo Shaper (998.150). The least value was of the V Taper file system (757.050). Conservative endodontic access (CAC) in the maxillary molars had shown significantly increased fracture resistance over TAC. SAF showed the maximum fracture resistance, while V-Taper files showed the least fracture resistance among the experimental groups compared.

Polymicrobial biofilm disinfection in maxillary and mandibular molars with varying access designs: A microbiological study

ABSTRACT Aim: The aim of the study is to evaluate and compare the effect of access cavity designs on the polymicrobial biofilm disinfection of root canal system. Methods: One hundred and twenty molar teeth were selected and randomly divided into four groups (n = 30) on the basis of access cavity design: traditional access cavity (TEC), contracted access cavity (CAC), truss access cavity (TAC), and caries-driven access cavity (CDAC). After access preparation, the samples were contaminated for 2 weeks to grow polymicrobial mature biofilm. Microbial sampling from the root canals was performed with sterile paper points before and after instrumentation to determine the bacterial load. The bacterial reduction was counted as CFU/ml and analyzed statistically. Results: Both maxillary and mandibular molars with different cavity designs showed significant decreased in the number of Enterococcus faecalis, Staphylococcus aureus, and Candida albicans postinstrumentation. TEC group showed significantly higher microbial reduction for all tested microorganisms than TAC and CDAC groups (P &lt; 0.05). However, insignificant difference (P &gt; 0.05) was observed between TEC and CAC and TAC and CDAC. Conclusion: In both maxillary and mandibular molars, complete elimination of microbes (E. faecalis, C. albicans, and S. aureus) could not be achieved with any access cavity design. Highest microbial reduction was achieved with TEC and lowest in CDAC. Both TEC and CAC resulted in equal microbial reduction and were superior to TAC and CDAC.

The Biomechanical Behaviour and life span of a Three-Rooted Maxillary First Premolar with Different Access Cavity Designs: A Finite Element Analysis.

The present study aimed to evaluate the influence of different access cavity designs on the biomechanical behaviour of a three-rooted maxillary first premolar using finite element analysis (FEA). Three experimental FEA models were generated: the intact tooth (IT) model, the traditional access cavity (TAC) model, and the conservative access cavity (CAC) model. In both TAC and CAC models, root canals preparation was simulated as follows: the mesiobuccal and distobuccal canals with a final tip size of 30 and taper of 0.04 and the palatal canal with a final tip size of 35 and taper of 0.04. Cyclic loading of 50 N was simulated on the occlusal surface of the three models. The number of cycles until failure (NCF), the location of failure, stress distribution patterns, maximum von Mises (VM), and maximum principal stress (MPS) were all evaluated and compared. Both types of access cavity preparation caused a reduction in the lifelog of the tooth; when compared to the IT model the TAC model had a lifelog of 94.82% while the CAC model had a lifelog of 95.80%. The maximum VM stresses value was registered on the occlusal surface of the TAC model (7 MPa), while the minimum was on the occlusal surface of the IT (6.2 MPa). MPS analysis showed that the highest stress value was recorded on the occlusal surface of the CAC model (7.71 MPa), while the least was recorded on the occlusal surface of the TAC model (3.77 MPa). Radicular stresses were always of minimal value regardless the model. The relation between the access cavity margins and the functional load points is a deciding factor that influences the biomechanical behaviour and fatigue life of endodontically treated teeth. (EEJ-2023-01-03).