METHODS: This narrative review was undertaken to address two main questions - why remove vital pulp tissue in teeth with complex canal anatomy when it can be preserved? And why replace the necrotic pulp in teeth with mature roots with a synthetic material when we can revitalize? This review also aims to discuss anatomical challenges with pulpotomy and revitalization procedures.
RESULTS: Maintaining the vitality of the pulp via partial or full pulpotomy procedures avoids the multiple potential challenges faced by clinicians during root canal treatment. However, carrying out pulpotomy procedures requires a meticulous understanding of the pulp chamber anatomy, which varies from tooth to tooth. Literature shows an increased interest in the application of RPs in teeth with mature roots; however, to date, the relation between the complexity of the root canal system and outcomes of RPs in necrotic multi-rooted teeth with mature roots is unclear and requires further robust comparative research and long-term follow-up.
CONCLUSIONS: Whenever indicated, pulpotomy procedures are viable treatment options for vital teeth with mature roots; however, comparative, adequately powered studies with long-term follow-up are needed as a priority in this area. RPs show promising outcomes for necrotic teeth with mature roots that warrant more evidence in different tooth types with long-term follow-ups. CLINICAL RELEVANCE: Clinicians should be aware of the pulp chamber anatomy, which is subject to morphological changes by age or as a defensive mechanism against microbial irritation, before practicing partial and full pulpotomy procedures. RP is a promising treatment option for teeth with immature roots, but more evidence is needed for its applications in teeth with mature roots. A universal consensus and considerably more robust evidence are needed for the standardization of RPs in teeth with mature roots.
Objectives: The aim of this review was to compare the various root and root canal morphology classifications, their advantages, limitations, and clinical and research implications. Data Sources and Selection. An extensive literature search was conducted on PubMed and Scopus to identify the published data on root and root canal classification systems published until 1 May 2020 using keywords, root canal classification system, classification systems for root canals, and root morphology. The related literature was reviewed and then summarized. Data Synthesis. Several studies have analysed and detailed root and root canal classifications and further added new subsystems, works of Weine et al. (1969) and Vertucci et al. (1974). Besides, Sert and Bayirli (2004) added supplementary types to Vertucci's classification system. A new classification was most recently introduced by Ahmed et al. (2017) involving the use of codes for tooth numbering, number of roots, and canal configuration.
Conclusions: Weine et al. classified only single-rooted teeth, without considering multirooted teeth and complex configurations. Vertucci's classification included complex configurations, with Sert and Bayirli adding further complex supplemental types. Ahmed et al.'s classification simplifies classifying root and canal morphology while overcoming the limitations of several previous classification systems making it beneficial for implementation in dental schools.
METHODS: One PowerPoint presentation describing two classification systems for root canal morphology (Oral Surgery Oral Medicine Oral Pathology, 1974 38, 456 and its supplemental configurations, International Endodontic Journal 2017, 50, 761) was delivered to final year undergraduate dental students in eight dental schools in Malaysia by two presenters (each presented to four schools). To examine students' feedback on the utility of each system, printed questionnaires consisting of six questions (five multiple choice questions and one open-ended question) were distributed and collected after the lecture. The questionnaire was designed to compare the classification systems in terms of accuracy, practicability, understanding of root canal morphology and recommendation for use in pre-clinical and clinical courses. The exact test was used for statistical analysis, with the level of significance set at 0.05 (P = 0.05).
RESULTS: A total of 382 (out of 447) students participated giving a response rate of 86%. More than 90% of students reported that the new system was more accurate and more practical compared with the Vertucci system (P 0.05). The students' responses for all questions were almost similar for both presenters (P > 0.05).
CONCLUSIONS: The new system of International Endodontic Journal 2017, 50, 761 for classifying root and canal morphology was favoured by final year undergraduate dental students in Malaysia. The new system has the potential to be included in the undergraduate endodontic curriculum for teaching courses related to root and canal morphology.
METHODS: Root canal preparation was performed using stainless steel K-files™ and F4 size protaper with irrigation protocols of 6% NaOCl + 2% CHX; 3.5% QIS; 2% QIS and sterile saline. Biofilms were prepared using E. faecalis adjusted and allowed to grow for 3 days, treated with irrigants, and allowed to grow for 7 days. AFM was performed and surface free energy calculated. MC3T3 cells were infected with endo irrigant treated E. faecalis biofilms. Raman spectroscopy of biofilms were performed after bacterial re-growth on root dentine and exposed to different irrigation protocols and collagen fibers analysed collagen fibers using TEM. Antimicrobial potency against E. faecalis biofilms and cytoxicity against 3T3 NIH cells were also. Resin penetration and MitoTracker green were also evaluated for sealer penetration and mitochondrial viability. Data were analysed using One-way ANOVA, principal component analysis and post-hoc Fisher's least-significant difference.
RESULTS: Elastic moduli were maintained amongst control (5.5 ± 0.9) and 3.5% QIS (4.4 ± 1.1) specimens with surface free energy higher in QIS specimens. MC3T3 cells showed reduced viability in 6%NaOCl+2%CHX specimens compared to QIS specimens. DNA/purine were expressed in increased intensities in control and 6% NaOCl + 2% CHX specimens with bands around 480-490 cm-1 reduced in QIS specimens. 3.5% QIS specimens showed intact collagen fibrillar network and predominantly dead bacterial cells in confocal microscopy. 3.5% QIS irrigant formed a thin crust-type surface layer with cytoplasmic extensions of 3T3NIH spread over root dentine. Experiments confirmed MitoTracker accumulation in 3.5% treated cells.
SIGNIFICANCE: Novel QIS root canal irrigant achieved optimum antimicrobial protection inside the root canals facilitating a toxic effect against the Enterococcus faecalis biofilm. Root dentine substrates exhibited optimum mechanical properties and there was viability of fibroblastic mitochondria.