Access Cavity Design Research Articles

Effect of different access cavity designs on fracture toughness of endodontically treated teeth: a systematic review and network meta-analysis.

Objective To compare the effect of different endodontic access cavities on fracture toughness of extracted endodontically treated human teeth.Data/sources An electronic literature search was performed in seven databases as well as hand search until September 2020. Risk-of-bias tool was used to evaluate the quality of included studies. Random effects frequentist network meta-analysis was performed, with mean difference (MD) and 95% confidence interval (CI) as the effect measure. Confidence in the documented evidence was assessed through the newly fuelled Confidence in Network Meta-analysis (CINeMA) framework based on the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.Study selection A total of 844 articles were obtained in the electronic and hand search. After the application of the eligibility criteria and duplicate removal, 14 studies were included in this systematic review. All included studies were in vitro that evaluated the influence of conservative endodontic cavities (CECs) on fracture toughness in extracted endodontically treated human teeth and compared to traditional endodontic cavities (TECs). In total, ten studies (n = 456) were included in the network meta-analysis for molars. The overall risk of bias was moderate.Results The results showed that when compared to intact teeth, the greatest reduction in fracture resistance was reported for TEC (MD: -927.52; 95% CI [-1304.80; -550.24]) and CEC showed least reduction in fracture resistance (MD: -365.59; 95% CI [-759.02; 27.83]). The surface under the cumulative ranking curve (SUCRA) value for intact teeth was highest (85.4% probability of being ranked as first), followed by CEC (51.4% probability of being ranked as second), with CEC presenting the highest probabilities to be the most effective access cavity design, according to the RANK (receptor activator of NF-kappaB) table. Level of confidence varied from low to moderate across all formulated comparisons.Conclusion Overall, based on the included in vitro studies in this systematic review, CEC was the most favourable access cavity design when compared to other (truss access cavities, TEC and ninja cavities) and TEC was the least favourable for fracture resistance; however, the level of evidence was moderate.

The Effect of Different Access Cavity Designs in Combination with WaveOne Gold and TruNatomy Instrumentation on Remaining Dentin Thickness and Volume

IntroductionThe purpose of this study was to evaluate and compare 2 different access cavity designs in combination with 2 popular single-file preparation systems to see which combination preserves dentin, more specifically pericervical dentin, best. The minimum remaining dentin thickness and dentin volumes were evaluated pre- and postinstrumentation. MethodsSixty extracted human mandibular molars were selected and randomly divided into 2 different access cavity design preparation groups: traditional access cavities (n = 30) and conservative access cavities (n = 30). Within each cavity preparation design group, the 30 teeth were divided into 2 instrumentation groups (WaveOne Gold Primary; Dentsply Sirona, Ballaigues, Switzerland [n = 15] and TruNatomy Prime, Dentsply Sirona [n = 15]). Samples were scanned using micro–computed tomographic imaging before and after access cavity preparation as well as after final endodontic instrumentation. The pericervical remaining dentin thickness and dentin volume changes were evaluated and compared. ResultsConservative access cavity designs resulted in more favorable remaining dentin thickness. The least amount of mean dentin volume loss was also recorded in the conservative access cavity preparation groups regardless of the preparation instrumentation. ConclusionsIn terms of the remaining pericervical dentin thickness and dentin volume reductions, the authors conclude that conservative access cavity designs preserve dentin best.

Traditional and Conservative Molar Endodontic Access Cavity Designs: A Classification and Overview

Minimally invasive endodontics' specific focus on dentine preservation is gaining popularity. Before deciding on the appropriate endodontic access cavity design, clinicians should investigate the advantages and disadvantages associated with different treatment modalities. The purpose of this article is to provide a summary of possible advantages and disadvantages of different endodontic access cavity designs with the focus on traditional, conservative and ultra-conservative endodontic access cavities, specifically in molar teeth. No conclusive evidence is found in the literature favouring one access cavity design above another and clinicians are advised to evaluate each case individually when deciding on the appropriate access cavity design for that specific case. Fracture resistance, proper shaping in order to facilitate irrigation and disinfection, as well as canal location and orifice detection are some of the contributing factors in selecting an appropriate access cavity design that will be highlighted in this article.

Assessment of the coronal root canal morphology of permanent maxillary first molars using digital 3D-reconstruction technology based on micro-computed tomography data

The design of minimally invasive access has become a hotspot. This study aimed to evaluate the coronal root canal morphology of permanent maxillary first molars to facilitate the design of endodontic access cavities for minimally invasive linear access. A selection of 91 permanent maxillary first molars was evaluated. Three-dimensional tooth models were reconstructed using micro-computed tomography data. Root canal prevalence and coronal root canal landmarks were recorded. The positional coordinates of landmarks in the horizontal plane and the angles and directions of coronal root canal curvature in the horizontal and axial planes were also assessed. The detection rates of the mesiobuccal (MB), distobuccal (DB), and palatal (P) canals were 100%, whereas that of the second mesiobuccal (MB2) canals was 68.1%. All landmarks were located near the central fossa. In the axial plane, the average angles of coronal root canal curvature were DB (27.05°)>MB (25.43°)>P (20.71°) in teeth with three canals, and MB2 (33.20°)>MB (29.61°)>DB (28.40°)>P (23.69°) in teeth with four canals. In the horizontal plane, the average angles were P (78.15°)>DB (42.34°)>MB (32.41°) in teeth with three canals, and P (81.26°)>DB (43.44°)>MB (41.22°)>MB2 (9.41°) in teeth with four canals. In maxillary first molars, coronal root canals tend to converge towards the occlusal surface. The results of this study could be applied to improve the precision of endodontic access cavity designs of minimally invasive access.

Influence of Access Cavity Design on the Fracture Strength of Endodontically Treated Teeth Restored Using Short Fiber-Reinforced Composite and High Strength Posterior Glass Ionomer Cement.

Aim: This in vitro study aimed to determine the influence of access cavity design and residual tooth structure and to compare the fracture resistance of the teeth post endodontically restored with short fiber-reinforced composite (GC everX Posterior; GC, India) and conventional posterior high-strength GIC (Glass Ionomer Cement) (GC Gold Label IX; GC, India).Methods: Ninety extracted human mandibular molars were classified into five groups, i.e., one control group (n = 10) and four test groups based on the access cavity design (n = 20): Traditional access cavity (TAC), Conservative access cavity (CAC), Ninja access cavity (NAC), and Truss access cavity (TRAC). Then 80 teeth in test groups were endodontically treated and further subdivided (n = 10) based on post-endodontic restorative materials, i.e., short fiber-reinforced composite (SFC) and Type 9 GIC. Samples were then subjected to fracture resistance under a universal testing machine and fracture loads were compared statistically.Results: The fracture resistance of various access cavity designs (TAC, CAC, NAC, and TRAC) varied significantly (P < .05). Regardless of access cavity design, teeth restored with SFC had higher fracture resistance than teeth restored with high strength posterior GIC (P = .001).Conclusion: Using newer access cavity designs like (CAC, NAC, and TRAC) and reinforcing the teeth with a post-endodontic restoration such as SFC, fracture resistance of endodontically treated teeth can be improved notably.

Comparison of Fracture Resistance of Endodontically Treated Teeth With Traditional Endodontic Access Cavity, Conservative Endodontic Access Cavity, Truss Endodontic Access Cavity, and Ninja Endodontic Access Cavity Designs: An In Vitro Study

Introduction: Endodontic access cavity preparation plays a vital role as preservation of enamel structure is of utmost importance for a tooth's strength to be maintained. As teeth become fragile after a root canal therapy, this study was designed to compare in vitro the fracture resistance of root-filled and restored teeth with traditional endodontic access cavity, conservative endodontic access cavity (CEC), ninja endodontic access cavity (NEC), and truss endodontic access cavity (TEC).Materials and methods: Control (intact teeth) and traditional endodontic access cavity as well as CEC, NEC, and TEC groups were each given a new human mandibular molar that was freshly removed. Cone beam computed tomography (CBCT) scans of the cone beam showed the values of CEC, NEC, and TEC. After that the teeth were endodontically treated and repaired. To test the specimens, universal testing equipment was used. In order to avoid tooth breakage, the maximum load was determined. Statistical analysis was used in the form of Kolmogorov-Smirnov and Levene tests, which were used to examine data for typical dispersion and consistency in change.Results: Intact teeth showed the highest resistance to fracture compared with other groups. TEC showed significantly higher resistance to fracture compared to the CEC design.Conclusions: It is possible, within the restrictions of this research, to infer that the TEC design enhanced tooth fracture strength in comparison with the CEC design.

Modern versus Traditional Endodontic Access Cavity Designs.

By creating a precise access cavity (AC) and finishing the pulp chamber, less invasive endodontic therapy attempts to improve conventional endodontic therapy. The cingulum, oblique ridge, and roof of the pulp chamber, which all play a vital role in functional activity, might be preserved to increase fracture resistance. To reduce tooth structure loss, endodontic new ACs have recently been created. The preparation of the conservative access opening had advanced to a new level with the advent of microscopes and improved root canal equipment. The conservation of the cervical dentin is the most essential factor in preserving the restored tooth's normal function and lifespan. In recent years, minimally invasive endodontics has posed a challenge to the traditional method.

Impact of endodontic access cavity design and thermo-cycling on fracture strength of root canal treated mandibular molar teeth

Aim: Aim of study is to evaluate the fracture resistance of the root canal treated Mandibular 1st and 2nd molar teeth with Conventional(TEC) access design and Truss(TREC) access design restored with composite resin and subjected to thermocycling. Method: 60 human 1st and 2nd molar (mandibular) teeth were randomly categorised into six (6) groups: CON (GroupI), TEC (GroupIII), TREC(GroupV) not subjected to thermocycling whereas CONTC (GroupII),TECTC(GroupIV) and TRECTC(GroupVI) subjected to thermocycling. Biomechanical preparation of the canals were done upto #F3 of Protaper gold rotary files (Dentsply) and obturated using gutta-percha points and restored using SDR bulk-fill composite(Dentsply). All samples were then subjected to thermo-cycling for 5000cycles between 15°C and 45°C for different time intervals and their fracture toughness tested under an Universal Tester with steel ball of diameter 5mm at a constant 1mm/min speed. Two-way and one-way ANOVA test employed for statistical analysis. Result: The fracture strength of teeth in TREC group had no notable variation with the control group (P&gt;0.05) without thermocycling. Both TEC and TREC designs notably reduced the fracture toughness after thermocycling (P&lt;0.05). The least fracture resistance was noted in TECTC group. Conclusion: TREC ought to increase the fracture resistance of root canal treated teeth after thermocycling.

Influence of access cavity design, sodium hypochlorite formulation and XP-endo Shaper usage on apical debris extrusion - A laboratory investigation.

This study assessed the amount of apically extruded debris during root canal preparation using XP-endo shaper and the supplemental use of XP-endo finisher comparing the use of traditional endodontic access or conservative endodontic access cavities and liquid or gel-based formulations of 5.25% sodium hypochlorite or distilled water as supplemental agents. Maxillary first premolar teeth (N= 148) were randomly divided based on their access cavity design and sub-grouped according to the supplemental agent used. The amount of extruded debris was analysed based on the dry weight of the debris collected using a previously established laboratory methodology. Debris extrusion occurred in all groups. Overall, the traditional endodontic access cavity design was associated with more debris extrusion compared to the conservative type. The use of sodium hypochlorite solution showed higher debris extrusion than the gel, whilst distilled water had intermediate values.

Present status and future directions: vertical root fractures in root filled teeth.

Vertical root fracture (VRF) is a common reason for the extraction of root filled teeth. The accurate diagnosis of VRF may be challenging due to the absence of clinical signs, whilst conventional radiographic assessment is often inconclusive. However, an understanding of the aetiology of VRFs, and more importantly, the key predisposing factors, is crucial in identifying teeth that may be susceptible. Thorough clinical examination with magnification and co‐axial lighting is essential in identifying VRFs, and although CBCT is unable to reliably detect VRFs per se, the pattern of bone loss typically associated with VRF can be fully appreciated, and therefore, increases the probability of correct diagnosis and management. The prevalence of VRFs in root filled teeth is significantly greater than in teeth with vital pulps, demonstrating that the combination of loss of structural integrity, presence of pre‐existing fractures and biochemical effects of loss of vitality is highly relevant. Careful assessment of the occlusal scheme, presence of deflective contacts and identification of parafunctional habits are imperative in both preventing and managing VRFs. Furthermore, anatomical factors such as root canal morphology may predispose certain teeth to VRF. The influence of access cavity design and root canal instrumentation protocols should be considered although the impact of these on the fracture resistance of root filled teeth is not clearly validated. The post‐endodontic restoration of root filled teeth should be expedient and considerate to the residual tooth structure. Posts should be placed ‘passively’ and excessive ‘post‐space’ preparation should be avoided. This narrative review aims to present the aetiology, potential predisposing factors, histopathology, diagnosis and management of VRF and present perspectives for future research. Currently, there are limited options other than extraction for the management of VRF, although root resection may be considered in multi‐rooted teeth. Innovative techniques to ‘repair’ VRFs using both orthograde and surgical approaches require further research and validation. The prevention of VRFs is critical; identifying susceptible teeth, utilizing conservative endodontic procedures, together with expedient and appropriate post‐endodontic restorative procedures is paramount to reducing the incidence of terminal VRFs.

The Effect of Different Molar Access Cavity Designs on Root Canal Shaping Times Using Rotation and Reciprocation Instruments in Mandibular First Molars

IntroductionThe aim was to compare the glide path and final preparation times of WaveOne Gold and TruNatomy in conjunction with two different endodontic access cavity designs in extracted human molar teeth. Methods60 extracted human mandibular molars with mesiobuccal canals were selected and randomly divided into two different access cavity design preparation groups (n = 30). Traditional access cavities (TAC) and conservative access cavities (CAC). Within each cavity design group, the 30 teeth were divided in to two instrumentation groups (WaveOne Gold Primary (n = 15) and TruNatomy Prime (n = 15)). Group 1: TAC, #10 stainless steel manual K-file followed by WaveOne Gold Glider and WaveOne Gold Primary. Group 2: CAC, #10 stainless steel manual K-file followed by WaveOne Gold Glider and WaveOne Gold Primary. Group 3: TAC, #10 stainless steel manual K-file followed by TruNatomy Orifice Modifier and Glider and TruNatomy Prime. Group 4: CAC, #10 stainless steel manual K-file followed by TruNatomy Glider and TruNatomy Prime. Glide path and final preparation times were recorded. ResultsShaping time with TruNatomy Glider in combination with TruNatomy Prime instruments were faster compared to the WaveOne Gold Glider/ WaveOne Gold Primary instruments regardless of the type of access cavity preparation. TAC design yielded faster preparation time (38.2 ± 4.57 seconds) compared to the CAC (55.6 ± 6.91 seconds) in the WaveOne Gold Glider/ WaveOne Gold Primary instrumentation group. No difference was found between the different access cavity design groups in combination with TruNatomy Glider/TruNatomy Prime preparation. ConclusionPreparation time with TruNatomy Glider and Prime instruments was significantly faster than WaveOne Gold Glider/WaveOne Gold Primary, regardless of the access cavity design. TAC design in combination with WaveOne Gold Glider/ WaveOne Gold Primary instrumentation resulted in faster preparation time compared to WaveOne Gold Glider/WaveOne Gold in combination with the CAC design.

Morphometric analysis of three-rooted mandibular first molars in a Slovene population: a macroscopic and cone-beam computed tomography analysis.

This study examined the root morphology of mandibular first molars (MFMs) with radix entomolaris (RE), which presents diagnostic and therapeutic challenges for clinicians. A total of 17 three-rooted MFMs were taken from a collection of extracted teeth. Root lengths and levels of furcations were measured with a digital calliper. The pulp floor configuration, root canal systems, and RE canal curvatures were evaluated using the cone-beam computed tomography scans. Radix entomolaris was either located disto-lingually, with its coronal portion fixed to the distal root (n = 16) or mid-lingually (n = 1). A literature search identified four additional cases of MFMs with RE located mid-lingually. In the present study, RE was significantly (p ≤ 0.001) shorter than the distal root (DR) and the mesial root, on average by 2.04 mm and 3.15 mm, respectively. The level of the distal furcation was significantly (p = 0.003) lower than that of the mesiodistal furcation, on average by 1.39 mm. The average divergence angle formed by the cervical portions of the RE and DR canals was 53.14°. All RE canals were severely curved (> 25°) in buccolingual direction. The RE orifice was located slightly disto-lingually to considerably mesio-lingually from the DR orifice. The traditional assumption of a disto-lingually located RE needs to be changed, even though this is the most prevalently found variant of this anatomy. The additional variant includes the presence of a mid-lingually located RE, which has implications for the endodontic access cavity design.

Impact of Different Access Cavity Designs and Ni–Ti Files on the Elimination of Enterococcus faecalis from the Root Canal System: An In Vitro Study

The present research aimed to reveal the in vitro effects of different endodontic file systems utilizing different endodontic access cavity designs on the elimination of Enterococcus faecalis from root canal systems. One hundred and fifty mandibular molar teeth were separated into three groups with respect to the access cavity design: traditional endodontic cavity (TEC), conservative endodontic cavity (CEC), and truss access cavity (TAC) (n = 50). After access cavity preparation, inolulation of teeth with E. faecalis was undertaken for 21 days. Following the first sampling (S1), further division of the groups into five subgroups (n = 10) was performed: ProTaper Gold, 2Shape, TruNatomy, Reciproc Blue, and WaveOne Gold. After instrumentation, bacterial sampling (S2) was performed. Bacterial reduction was evaluated in colony-forming units/mL, and statistical analysis was carried out. The E. faecalis count decreased significantly in all groups (p &lt; 0.05). The range of mean values for a decrease in E. faecalis in log numbers was lowest in the TAC and Reciproc Blue groups, while the highest values of bacterial reduction were detected in the TEC and ProTaper Gold groups. The highest level of antibacterial action was obtained with the use of ProTaper Gold compared to the other file systems tested.

Influence of the endodontic access cavity design and restorative technique on hard tissue removal and fracture resistance of mandibular premolars

This study assessed the influence of traditional (TradAC) and conservative access (ConsAC) with different restorative techniques on the percentage of hard tissue removed (%HTR) and on the fracture resistance of mandibular premolars. 45 premolars were scanned in a micro-computed tomography and assigned into four groups according to access (TradAC or ConsAC) and restorative technique: composite resin (CR) or fiber post (FP) + CR. After post preparation, the teeth were rescanned to determine the volume enlargement and %HTR from the crown and root canal. After restoration, the load at fracture was recorded. Data were analyzed statistically by one-way ANOVA and Tukey’s post-hoc test, ANOVA repeated measure, and chi-square tests (P&lt;0.05). TradAC (RC or FP) resulted in the increase (Δ%) of root canal volume and hard tissue removed up to 14 mm (%) in comparison with ConsAC (RC or FP). TradAC + FP removed a greater percentage of hard tissue from the crown when compared to TradAC + CR. The percentage of hard tissue removed in the crown in the ConsAC groups was statistically lower than in the TradAC groups. The control group showed higher fracture resistance than all experimental groups, with no differences among the latter. Restorable fracture patterns were more prevalent. Traditional endodontic access cavities removed a higher percentage of dentine than conservative endodontic access cavities. However, no differences in fracture resistance were observed. Restorations using composite resin or fiber post associated with composite resin showed similar results of fracture resistance.

Comparative evaluation of different access cavity designs on intracoronal bleaching of endodontically treated teeth using two different agents – An in vitro study

Aim: The present in vitro study was designed to determine the effect of different access cavity designs on intracoronal bleaching of endodontically treated teeth with two different agents.Materials and Methods: Fifty selected permanent maxillary central incisors were stained. Traditional and contracted access cavity designs and two types of bleaching agents, i.e., 35% carbamide peroxide and 35 percent hydrogen peroxide were used for the study. Color measurements were performed with a spectrophotometer: before staining (T1), after staining (T2), at 7 and 14 days (T3 and T4) post bleaching. The values were calculated and subjected to the statistical analysis.Results: The results of our study showed that teeth in which traditional access cavity (TAC) was prepared had statistically significant better bleaching results with both 35% carbamide peroxide and 35% hydrogen peroxide than contracted access cavity design. Carbamide peroxide showed better results than hydrogen peroxide irrespective of the access cavity design, but difference was statistically nonsignificant.Conclusion: The present study concluded that TAC design showed better results than contracted access with both carbamide peroxide and hydrogen peroxide. Whereas, when bleaching agents were compared 35% carbamide peroxide is better than 35% hydrogen peroxide irrespective of access cavity design used.

Cusp deflection and fracture strength of root canal filled premolars with two access cavities designs (Conservative vs Traditional).

BackgroundThis study evaluated two endodontic access designs (Conservative (Cons) vs Traditional (Trad)) of class I and class II cavities on cusp deflection (CD) and fracture strength (FS) of root canal filled maxillary premolars. Material and MethodsSeventy-two sound maxillary first premolars were included in this study; Teeth were randomly assigned into nine groups (n=8), a positive control group where teeth left sound and the other eight according to the access cavity designs (Cons class I, Trad class I, Cons class II and Trad class II). After access preparation, teeth were endodontically-treated. Four groups were restored with FiltekTM Bulk-Fill composite. While the other four groups were left without coronal restoration as negative controls for fracture strength. Following thermocycling (500 cycles), CD values were recorded for the restored teeth at the following intervals, after cavity preparation, 15 min after restoration and after thermocycling. The samples were then subjected to fracture using a universal testing machine. The data were analyzed using one-way ANOVA and Tukey Post-Hoc. Statistical significance was set at p<0.05. ResultsThere was a significant difference between groups at 15 min after restoration (p<0.000) and there were no differences after cavity preparation and after thermocycling (p>0.05). At 15 min after restoration, the CD value was significantly higher in Trad class II than in other types of cavities (p<0.05) and there was no difference between Cons and Trad class I (p>0.05). In each group, the CD value was significantly higher 15 min after restoration compared to that after cavity preparation and after thermocycling in all groups. The highest FS was recorded for the control group (1240 N), while the lowest was for the Trad class II not restored group (472.8 N). One-way ANOVA test showed a highly significant difference between groups (p<0.000) and there were no significant differences in FS between the Cons vs Trad access cavity designs in class I and class II cavities, respectively. ConclusionsCusp deflection increased by the increase in the size of cavity preparation and stress relaxation tends to occur after thermocycling. Moreover, the conservation of the endodontic access cavity could improve the resistance of the tooth to fracture compared to its traditional counterpart but not to a statistically significant point. Key words:Conservative, traditional, endodontic access cavity, cusp deflection, fracture strength.

Effect of guided conservative endodontic access and different file kinematics on debris extrusion in mesial root of the mandibular molars: An in vitro study.

Guided conservative endodontic access is a novel technique and the influence of such access cavities on apical debris extrusion (ADE) can have a significant effect on postoperative pain. This study compared ADE and preparation time (PT) in the mesial canals of the mandibular first permanent molars in different access cavity designs and the amount of sodium hypochlorite in the extruded debris using attenuated total reflection-Fourier transform infrared spectrometer (ATR-FTIR). Human mandibular first permanent molars (N = 72) were selected and randomly divided into six groups (n = 12) based on type of cavity design and files used: Group 1, Conservative Access Cavity [ConsAC])-WaveOne Gold; Group 2, ConsAC-Mtwo; Group 3, ConsAC-XP-endo shaper; Group 4, Traditional Access Cavity [TradAC])-WaveOne; Group 5, TradAC-Mtwo; and Group 6, TradAC-XP-endo shaper. All the ConsAC were prepared with a customized template fabricated using cone beam computed tomography. ADE evaluation was done using the Myers and Montgomery set up. All the instruments were used according to the manufacturers' instructions, followed by a final irrigation using Endoactivator. The time taken for preparation was calculated using a digital watch. Five samples in each group was taken and subjected to ATR-FTIR analysis. There was no significant difference between the groups with respect to ADE (P > 0.05). Whereas, a statistically significant difference was seen in PT between the TradAC and ConsAC (P < 0.05). Using ATR-FTIR, it was found that all the samples of extruded debris had the presence of sodium hypochlorite. All instrumentation systems produced ADE irrespective of access cavity design. The time taken for preparation of canals in ConsAC was significantly longer compared to TradAC. ADE can translate clinically as postoperative pain. Assessing the ADE in ConsAC could shed light on the type of file systems that can be used in such cavities in order to minimize postoperative pain clinically.

The effect of bulk-fill composites: Activa and Smart Dentin Replacement on cuspal deflection in endodontically treated teeth with different access cavity designs.

Aim:The aim was to evaluate the effect of bulk-fill composites – Activa and Smart Dentin Replacement (SDR) on cuspal deflection in endodontically treated teeth with different access cavity designs.Materials and Methods:Forty-two maxillary first premolar teeth were randomly divided into three experimental groups based on different access designs as Group I – conservative endodontic cavities (CECs), Group II – traditional endodontic cavities, and Group III – CECs with diverging walls and two subgroups, based on the different access cavity restorations subgroup A-Activa and subgroup B-SDR with n = 7 per group. Root canal treatment was completed under the dental operating microscope. Cuspal deflection was assessed by measuring the distance between the glass beads using an optical microscope and micrometer immediately after a Root canal treatment and final measurements after access restorations. Data were statistically analyzed and tabulated.Results:Results showed that the access cavity restored with Activa showed the highest cuspal deflection than SDR in all the groups (P < 0.05). Conservative access designs showed the least cuspal deflection among other groups.Conclusion:CEC designs showed lesser cuspal deflection than traditional endodontic cavity designs. SDR can be considered as a choice of material for access restorations.

Impact of Access Cavity Design and Root Canal Taper on Fracture Resistance of Permanent Mandibular Molars: An In-vitro Study

Introduction: Minimal invasive endodontics in the form of conservative access designs and minimal root canal taper preparation have been devised to preserve tooth structure and increase fracture resistance. Aim: To assess the influence of two different access cavity designs and two different final preparation tapers on fracture resistance of mandibular molars. Materials and Methods: In this in-vitro study, performed over a period of two months, a total of 54 extracted human permanent mandibular first and second molar teeth with completely formed apices were selected and for infection control, the teeth were stored in 10% buffered formalin solution for two weeks before the experiment. The teeth were then randomly allocated into three groups, Group C where no tooth preparation was carried out, Group TAC in which traditional access cavity design was performed and Group TREC where Truss access cavity was performed. The groups TAC and TREC were further subdivided into subgroup A and B with two different tapers 0.04 and 0.06 taper preparations. Mesial canals of the teeth were chosen for testing the minimal root canal taper preparations. After apical gauging the distal canals, obturation and postendodontic restoration was carried out in all teeth of both the test groups. The teeth in all three groups were subjected to fracture testing in a universal testing machine. The data were recorded. Oneway Analysis of Variance (ANOVA) and Tukey Post-hoc test were used for statistical analysis. Results: The fracture resistance between group C and groups TAC and TREC and their subgroups were found to be statistically significant (p&lt;0.05). However, there was no statistically significant difference (p&gt;0.05) observed between the two test groups TAC and TREC and their subgroups. Conclusion: The conservative truss access design in combination with a reduced root canal taper preparation has shown to have produced better fracture resistance values in comparison to other groups and their subgroups although the results were not statistically significant.

A Literature Review of Minimally Invasive Endodontic Access Cavities - Past, Present and Future.

Minimally invasive endodontic access cavities have gained popularity in academic discussions for their clinical applications in recent years. Although some studies showed an improved fracture resistance of endodontically-treated teeth accessed with a minimally invasive access cavity design, the resulting effectiveness and efficiency of subsequent root canal treatment procedures may be impaired. Aspects that may be impaired are canal detection and negotiation, chemomechanical debridement of the root canal system, quality of the obturation. These are potentially complicated by the increased incidence of procedural mishaps and compromised aesthetic outcomes. In addition, the inherent flaws presented in the methodology of some in vitro studies and the lack of a universal classification system are also of concern. This literature review aims to present a comprehensive overview of the development of the minimally invasive endodontic access cavity and summarise the currently available from a clinical context.