Introduction. While there are many root morphology classification systems with their own distinct advantages, there are many shortcomings that come along with each system. 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 Vertuccis 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. Vertuccis 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.

Introduction. The main aims of root canal instrumentation are to provide an environment that will lead to healing and to provide a root canal shape that is comfortable to clean and seal. When working with rotary endodontic instruments, the most significant concerns are that the instrument might fracture in the root canal, thus affecting the treatment outcome. Hence, it is of immense importance to know which file systems have more cyclic fatigue resistance. Methodology. This study evaluated the effect of the curved segment length of the artificial canal (the arch), and the number of cycles necessary in fracture of Hyflex EDM, Twisted files, and ProTaper Gold were recorded. Sixty NiTi rotary instruments of 25mm length (Hyflex EDM (20), Twisted files (20), and ProTaper Gold (20)) were tested in a metal block with simulated canal having 90° angle of curvature. The study was performed with a specific radius and degree of curvature, i.e., 8mm radius and 90 angle of curvature, and data obtained were subsequently subjected to statistical evaluation using one-way analysis of variance and Tukeys post hoc test. Result. The Hyflex EDM (774.29) exhibited the maximum cyclic fatigue resistance compared to Twisted files (654.875) and ProTaper Gold (375.575). A statistically significant difference was observed between the tested groups. Conclusion. The Hyflex EDM files showed the highest cyclic fatigue resistance, followed by Twisted files and ProTaper Gold files.

Aim: This study compares the microhardness, water sorption and solubility of nano-zirconia-reinforced biodentin groups to commercially available biodentine. Materials and Methods: Samples were prepared by adding different percentages of nano zirconia to biodentin. Four groups were categorized as follows: group 1 used Biodentin as the control group, group 2 used 10% nano zirconia and 90% Biodentine, group 3 used 20% nano zirconia and 80% Biodentine, and group 4 used 30% nano zirconia and 70% Biodentine. A Vickers microhardness tester was used to measure the microhardness of the groups according to ISO 4049/2000. The water sorption and solubility of the divided groups were assessed using disk-shaped molds. The second weight was measured on an electronic weight machine after two weeks, and values were recorded. FTIR analysis was performed. Vickers microhardness, water sorption and solubility were analyzed using a one-way ANOVA, and for multiple comparisons, a post hoc Tukey’s HSD test with a significance level of p < 0.05 was performed. Group 3 had the highest mean microhardness measurement among all groups. The microhardness values for all groups in descending order are as follows: group 3, group 2, group 1 and group 4 (p = 0.008). Group 2 showed the lowest mean of water sorption compared among all groups. Group 2 has the lowest mean of water sorption, followed by group 3, group 1 and group 4 (p = 0.002). Group 4 showed the highest water sorption among all groups. Group 4 exhibited the highest solubility mean among all groups. Group 1 had the lowest mean of solubility, followed by group 2, group 3 and group 4 (p = 0.000). The FTIR spectra of different types of biodentin showed the absorbance peaks of the precipitates of each modified biodentin. The absorbance peaks fell between 474.63 cm⁻¹ and 3438.33 cm⁻¹. Conclusion: Biodentin is a competitive biomimetic material, but it lacks hardness and has more solubility. Thus, adding nano zirconia improved microhardness and reduced water sorption. The solubility of 20% nano zirconia added to biodentin was almost close to biodentin but with no significance. The 20% nano-zirconia-modified biodentin showed overall better properties compared to biodentin. The 20% nano-zirconia-modified biodentin can be used in deep cavities as a single restorative material instead of multi-layered restorations to increase longevity without microleakage and failure of restoration.

The successful outcome of endodontic treatment is dependent on complete cleaning, shaping as well as three dimensional obturation of the root canal system. A conventional radiograph is a two-dimensional replication of a three-dimensional object and does not provide any conclusive evidence for canal curvatures. An accurate knowledge of the tooth anatomy and curvature is essential to avoid procedural errors. 100 freshly extracted human teeth were used in this study. Digital images were obtained using the plywood JIG and Schneider’s technique. These images were analyzed using the VixWin Pro digital image analyzing software (Gendex system). Statistical analysis was done using paired t test. The canal curvature average values measured using Jig method and Schneider method for mandibular teeth are 28.23° (±9.96) and 22.07° (±9.46) respectively. The smallest/largest curvature angles measured using Jig method and Schneider technique are 12/52° and 8/44° respectively. Canal curvature average values measured using Jig method and Schneider method for maxillary teeth were 23.40° (±11.36) and 19.23° (±11.94) respectively. The smallest/largest average curvature angles measured using Jig method, Schneider technique were 9/70° and 5/72° respectively. The values of the canal curvature angle obtained during routine radiographs in clinics have lower curvature angle and higher radius values as compared to the values obtained by this innovative JIG technique. Therefore, a clinician should always keep in mind the difference while measuring the curvature angle on radiographs during root canal treatment.

To evaluate the percentage of gutta-percha filled areas (PGFA) in canals obturated with guttacore system, single cone, and lateral compaction techniques. A total of 60 single-rooted mandibular premolars were selected and randomly divided into three equal groups depending on the type of obturation technique used. After the obturation, the samples were marked at 2, 4, 6, and 8 mm distance from the apex and sectioned horizontally, and viewed under a stereomicroscope at 25×. The area of the canal and of the filling material was recorded, and the percentage of filling material on the canal wall was calculated. Guttacore showed the highest percentage of root-filled areas followed by single cone and lateral compaction techniques at 2, 4, 6, and 8 mm from the apex. None of the filling techniques used in the study was completely able to fill the root canals with gutta-percha and sealer. The guttacore system had a maximum area of root canals filled as compared to the single cone and lateral compaction system. Root canals are mostly oval, elongated, or irregularly shaped rather than being completely round. Hence, the obturation technique that fills the maximum area of the root canal must be selected according to the given clinical circumstances.

Self-adhesive dual-cure resin cements (DCRC) simplified clinical application to a single-step procedure. Studies reported inferior mechanical properties compared to conventional resin cements. This study evaluated and compared the compressive strength (CS) and flexural strength (FS) of commercial DCRC against its modification using 10 vol% nanozirconia and 10 vol% nanodiamond. Three groups were prepared: Group 1 (commercial resin cement), Group 2 (nanozirconia-modified), and Group 3 (nanodiamond-modified), with 10 samples per group. 3-(Trimethoxysilyl) propyl methacrylate was used as coupling agent. Specimens were prepared according to manufacturer instructions and tested for CS and FS using a Universal Instron testing machine. Data was analysed using one-way ANOVA and Tukey’s post hoc test. Compressive strength values were Group 2 = 132.18 ± 27.93 MPa, Group 3 = 126.21 ± 12.54 MPa, Group 1 = 121.12 ± 19.35 MPa. Flexural strength values were Group 2 = 72.5 ± 10.4 MPa, Group 3 = 71.06 ± 6.3 MPa, Group 1 = 66.92 ± 5.27 MPa. Both nanozirconia and nanodiamond incorporation showed improvements in CS and FS compared to the control group. Within the limitations of this study, nanozirconia modified dual cure resin cement showed higher values compared to nanodiamond modified dual cure resin. These results support further research to optimize nanofiller-reinforced luting cements.