Current strategies for conservative endodontic access cavity preparation techniques—systematic review, meta-analysis, and decision-making protocol

Abstract

Objectives To assess related studies and discuss the clinical implications of endodontic access cavity (AC) designs. Materials and methods A systematic review of studies comparing the fracture resistance and/or endodontic outcomes between different AC designs was conducted in two electronic search databases (PubMed and Web of Science) following the PRISMA guidelines. Study selection, data extraction, and quality assessment were performed. Meta-analyses were undertaken for fracture resistance and root canal detection, with the level of significance set at 0.05 (P = 0.05). Results A total of 33 articles were included in this systematic review. The global evaluation of the risk of bias in the included studies was assessed as moderate, and the level of evidence was rated as low. Four types of AC designs were categorized: traditional (TradAC), conservative (ConsAC), ultraconservative (UltraAC), and truss (TrussAC). Their impact on fracture resistance, cleaning/disinfection, procedural errors, root canal detection, treatment time, apical debris extrusion, and root canal filling was discussed. Meta-analysis showed that compared to TradAC, (i) there is a significant higher fracture resistance of teeth with ConsAC, TrussAC, or ConsAC/TrussAC when all marginal ridges are preserved (P < 0.05), (ii) there is no significant effect of the type of AC on the fracture resistance of teeth when one or two marginal ridges are lost (P > 0.05), and (iii) there is a significantly higher risk of undetected canals with ConsAC if not assisted by dental operating microscope and ultrasonic troughing (P < 0.05). Conclusions Decreasing the AC extent does not necessarily present mechanical and biological advantages especially when one or more surfaces of the tooth structure are lost. To date, the evidence available does not support the application of Trus-sAC. UltraAC might be applied in limited occasions. Clinical relevance Maintaining the extent of AC design as small as practical without jeopardizing the root canal treatment quality remains a pragmatic recommendation. Different criteria can guide the practitioner for the optimal extent of AC outline form which varies from case to case.

Influence of minimally invasive access cavities on load capacity of root‐canal‐treated teeth: A systematic review and meta‐analysis

“…Our review also differentiated the groups based on the type of teeth and restorative materials. This approach was in opposition to the fairly new systematic reviews published on this matter [26,27] and therefore yielded more specific results that are more appropriate for intervention treatment decisions. In addition the aforementioned potential sources of heterogeneity, age of specimen teeth and extraction and storage conditions should be considered due to their potential effect on their microstructural properties [16].…”

“…Over time, additional ex vivo studies have been conducted with results that are contradictory to the previously published systematic review [14, 18]. Some other recent systematic reviews [26, 27] have also concluded non‐significant differences between access cavities regarding the load capacity of the tested teeth. However, the main shortcomings of these newer studies were not taking account the biomechanic differences between the types of teeth and restorative materials [26] or the absence of premolars and anterior teeth their discussions [27].…”

Regenerative Endodontics and Minimally Invasive Dentistry: Intertwining Paths Crossing Over Into Clinical Translation

“…Starting from the access cavity design, CEC for non-decayed traumatized teeth and caries-driven-access cavity for decayed teeth, would represent more suitable tooth preserving designs, where the volume of dentin and enamel removal in case of CEC designs was found to be less than 15% which was significantly less than enamel and dentin removal in TEC ( Isufi et al, 2020 ). Additionally, according to a recent systematic review and meta-analysis, a significant increase in fracture resistance was noted when CEC preparation was performed with preservation of tooth marginal ridges ( Ballester et al, 2021 ). Thus this approach, accompanied by minimal mechanical preparation of root canal walls ( El-Kateb et al, 2020 ), would offer a chance to preserve the coronal tooth structure and maximize the release of growth factors sequestered within the pericervical dentin ( Tziafas et al, 2019 ).…”

Guided Endodontics: A Literature Review

“…In the study by Gambarini G et al [ 21 ], ultra-conservative access (comparing DGE and manual) consisting of linear access to the teeth was performed with the aim of minimizing tooth weakness, preserving as much tooth tissue as possible, and reducing instrument stress during treatment. Endodontic access cavities are a controversial subject; the terminology is inconsistent [ 82 ], and there are multiple classifications for these accesses [ 47 ]. They could be broadly classified as: traditional (the pulp chamber roof is removed, and the coronal third of the canals are accessed directly), conservative (the access is made in the central fossa and expanded just enough to locate the canals), ultra-conservative (minimal access in the deepest center of the tooth), and truss access cavities (oval cavities guided by micro-CT imaging where the pulp chamber roof is preserved between the accesses and depending on the diameter of the rotary instruments subsequently used) [ 83 ].…”