Comparative Analysis of Fracture Strength of Remaining Tooth Structure after Endodontic Treatment with Various Access Cavity Preparation Techniques

Abstract

Background: A perfect balance needs to be maintained between various types of endodontic access cavity preparation designs like - Traditional and conservative designed preparation to have access to the root canal system for proper cleaning and shaping of root canals without compromising the fracture resistance of the tooth structure. Aims and Objectives: We aimed to assess as well as draw comparisons of resistance against fracture of remaining tooth structure post the endodontic treatment after preparing access cavity through a variety of techniques so that we can estimate which type of cavity design technique will help endodontically treated teeth to withstand excessive load without fracture. Methods: Forty-two intact teeth (mandibular molars) were randomly selected and then were assigned to 07 different groups, inclusive of control and test groups. Various designs of access cavity preparation were done on sample teeth. The groups were divided based on different access cavity preparation designs as well as residual walls. The samples were then mounted on a composite cylinder, which was loaded under a mechanical testing machine at 0.5mm/min speed till the tooth structure fractured. This measurement of force was denoted in newton. The later analysis was carried out with the help of two-way Analysis of Variance (ANOVA) as well as Tukey’s post-hoc statistical tests. Results: There was negligible statistically relevant variance in strength towards fracture between traditional and conservative designs in teeth having three remaining walls. However, teeth with only two remaining walls fractured easily. Conclusion: Fracture resistance of teeth with remaining 03 residual walls did not show any significant difference among Traditional (TEC) and Conservative Cavity (CEC) design groups, but increased fracture strength was reported in CEC with 02 residual walls.

Present status and future directions – Minimal endodontic access cavities

“…One of the most important methodological aspects of research design is the creation of a reliable baseline inasmuch as anatomical discrepancies of sampling may have a direct impact on the outcome. Although it seems logical that a proper anatomical pairing of teeth allocated for each experimental group may compromise the final conclusions, several studies performed sample selection based only on two‐dimensional radiographs (Corsentino et al, 2018; Krishan et al, 2014; Moore et al, 2016), external measurement of teeth (Corsentino et al, 2018; Ivanoff et al, 2017; Marinescu et al, 2020; Maske et al, 2021; Özyürek et al, 2017; Plotino et al, 2017; Roperto et al, 2019; Saberi et al, 2020; Sabeti et al, 2018; Spicciarelli et al, 2020) or merely by random allocation into the experimental groups (Chlup et al, 2017; Makati et al, 2018; Mustafa et al, 2020; Reddy et al, 2020). To overcome these sampling limitations, De‐Deus et al (2020) demonstrated that micro‐CT technology is the recommended method to pair‐match extracted teeth based on their anatomical characteristics (Figure 24).…”

“…After using a strict selection criterion, specimen preparation for the fracture test is also a critical step that may affect the experimental results. In some studies, different types of occlusal cavities were prepared prior to accessing the pulp chamber in an effort to simulate a common clinical scenario observed in teeth referred for endodontic treatment (Abou‐Elnaga et al, 2019; Corsentino et al, 2018; Ivanoff et al, 2017; Mustafa et al, 2020; Özyürek et al, 2017; Reddy et al, 2020) (Table 5). Mustafa et al (2020) reported greater fracture resistance of teeth with ConsAC than TradAC only when teeth had two residual walls, while no difference was observed in the presence of three residual walls.…”

“…Consequently, it would be expected that a well‐controlled laboratory study should take into consideration the external and internal morphologies of teeth as sampling criteria to increase the internal validity and reliability of the study. Nevertheless, whilst four studies did not report how sample selection was performed (Chlup et al, 2017; Makati et al, 2018; Mustafa et al, 2020; Reddy et al, 2020), most of them used the external measurement of teeth and/or conventional radiographic examination to select and allocate the specimens into experimental groups (Corsentino et al, 2018; Ivanoff et al, 2017; Karobari et al, 2021; Krishan et al, 2014; Marinescu et al, 2020; Maske et al, 2021; Moore et al, 2016; Özyürek et al, 2017; Plotino et al, 2017; Roperto et al, 2019; Saberi et al, 2020; Sabeti et al, 2018; Santosh et al, 2021; Spicciarelli et al, 2020). Even though it is yet to be proven, this lack of anatomical matching raises questions regarding the trustworthiness of their results.…”

“…Regarding sample preparation before the fracture resistance test, in some studies, root canals were not prepared (Mustafa et al, 2020; Sabeti et al, 2018) or filled (Ivanoff et al, 2017; Krishan et al, 2014; Moore et al, 2016; Mustafa et al, 2020; Sabeti et al, 2018), and the crowns were not restored (Krishan et al, 2014; Mustafa et al, 2020; Sabeti et al, 2018) (Table 5). Notwithstanding the authors' justification that these procedures avoided adding confounding factors to the variables, it was not taken into consideration that the dentine removed by mechanical preparation would also affect the fracture resistance of teeth (Tang et al, 2010), the canal filling might contribute to the re‐establishment of the fracture resistance of teeth (Sandikci & Kaptan, 2014), and the restoration can recover the fracture resistance of root filled teeth by approximately 80% (Hamouda & Shehata, 2011).…”

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

“…A number of ex vivo studies demonstrate poor standardization of the included teeth using either direct external measurement or two‐dimensional radiographic techniques; this prevents appropriate matching of the sample selection in respect of pulp chamber volume or the residual thickness, height and volume of dentine (Corsentino et al, 2018; Ivanoff et al, 2017; Krishan et al, 2014; Marinescu et al, 2020; Maske et al, 2021). Furthermore, some studies fail to describe how the included sample selection were chosen at all (Chlup et al, 2017; Makati et al, 2018; Mustafa et al, 2020; Reddy et al, 2020). To highlight the relevance of this point, studies carried out using micro‐CT for accurate sample selection matching, as well as pre‐ and post‐experimental assessment of pulp chamber volume, dentine thickness, height and volume, consistently show no difference in the fracture resistance of teeth prepared with minimally invasive access cavities (Augusto et al, 2020; Barbosa et al, 2020; Lima et al, 2021; Rover et al, 2017).…”