Scope of Preparation of Oval and Long-Oval Root Canals: A Review of the Literature

Abstract

Successful endodontic treatment depends on cleaning and disinfecting the root canals, in order to provide conditions for three-dimensional filling, which should prevent root canal reinfection. However, anatomical complexities pose a challenge during endodontic treatment. The present study was a literature review carried out in the following databases: PubMed, SciELO, and MEDLINE, which were searched for articles published from 2017 to 2021. Micro-CT studies published in English, which analysed the capacity for preparation of oval and long-oval root canals, were included. The following keywords were used: “oval-shaped canals,” “long-oval-shaped canals,” “endodontics,” and “micro-CT.” The aim of this study was to carry out a literature review of micro-CT studies on the scope of the capacity for preparation performed in oval and long-oval root canals with rotary and reciprocating instruments.

The Effect of Combined Ultrasonic Tip and Mechanized Instrumentation on the Reduction of the Percentage of Non-Instrumented Surfaces in Oval/Flat Root Canals: A Systematic Review and Meta-Analysis

“…According to the literature classification, canals with a buccolingual diameter less than twice the mesiodistal diameter are considered "round or slightly oval". Canals with a buccolingual diameter two to four times greater than the mesiodistal diameter are defined as "long oval or flattened canals", which may vary along the thirds of the tooth [10,27]. The instrumentation of these oval or flattened canals is an anatomical challenge since they have flattened areas that are difficult to access, and difficult in modeling and instrument choice [16].…”

Assessing Percentage of Touched Surfaces and Changes in Cross-sectional Area in Oval Shaped Root Canals after XP-endo Shaper, IRaCe and HyFlex CM Instrumentation Using AutoCAD Software

“…Due to the difficulty of the anatomical configuration of the oval root canal surfaces, where the buccolingual canal diameter was at least twice the mesiodistal diameter so lower permanent mandibular premolars with a single oval canal were included [19], [20]. Many studies have found that after hand and rotary instrumentation, buccal and lingual extensions of oval-shaped canals were untouched, potentially harboring necrotic pulp tissue, bacterial biofilms, and dentin debris [21], [22], [23].…”

“…This helped the evaluator easily detect canal areas that had been touched by the rotary instrument, which ensured reliable calculations while minimizing bias. AutoCAD was used to study different parameters, such as measuring root canal curvature, calculating the number of touched canal walls, determining the instrument's cross-sectional measurements, assessing instrument shaping ability, and during root canal retreatment to evaluate efficacy of various instruments in removing gutta-percha and sealer [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33].…”

Morfología inusual de raíz y canales del primer molar mandibular, como indicación de tomografía computarizada de haz cónico: A propósito de un caso endodóntico "fronterizo"

“…Todo esto conlleva un desafío implícito para el endodoncista quien deberá realizar una correcta planificación del caso. Los canales ovales son complejos de tratar endodónticamente, especialmente durante la preparación quimiomecánica, debido a que tienen zonas de difícil acceso las cuales favorecen la acumulación de detritus y dificultan la eliminación de microorganismos (19) . Además, los instrumentos tienden a centrarse en el canal impidiendo una correcta conformación y desinfección, especialmente en sentido bucolingual (20) .…”