Comparison of the sealing ability amongst orthograde apical plugs of mineral trioxide aggregate plus, mineral trioxide aggregate repair HP, and Biodentine after root resection: a bacterial leakage study.

This study aimed to analyse the effect of root-end resection on the sealing ability of orthograde apical plugs of three root-end filling materials (MTA Repair HP, Biodentine, MTA Plus) using the bacterial leakage method and compare it with the retrograde root-end filling technique. Eighty-four extracted mandibular premolar teeth with single root and single straight canals were selected and randomly divided into two main experimental groups (n = 36) depending on the apical plug placement technique and a control: Group I: orthograde technique, followed by root-end resection; Group II: retrograde root-end filling technique; one control Group III (n = 12): obturation with gutta-percha, followed by root-end resection. Experimental groups were further subdivided into three subgroups A, B, and C (n = 12) depending on the three different root-end filling materials used. An apical plug of 3 mm thickness was obtained in both the experimental groups. The apical sealing ability was evaluated with the dual-chamber bacterial leakage method. Statistical analysis was performed using the Kaplan-Meier survival analysis test. By the end of 30 days, the occurrence of turbidity indicating bacterial leakage was 75% in MTA Repair HP, 83.3% in Biodentine, and 91.7% in MTA Plus samples. This trend of turbidity was similar in both orthograde and retrograde technique. The control group showed turbidity in all the samples (100%). More MTA Repair HP samples (25%) survived the 30 days observation period with no bacterial leakage compared to Biodentine (16.7%) and MTA Plus (8.3%). The sealing ability of already set root-end filling materials placed through the orthograde technique did not deteriorate after root-end resection. Also among three root-end filling materials, MTA Repair HP presented the lowest bacterial microleakage followed by Biodentine and MTA Plus, respectively.

Radicular dentinal microcracks during biomechanical root canal preparation using four minimally invasive endodontic files.

Aim: The aim of the study was to compare the dentinal microcrack formation on human mandibular molars using 4 different minimally invasive file systems at 3, 6 and 9 mm from apex using a stereomicroscope. Method: 125 mesial roots of mandibular molars were randomly divided into 5 groups and instrumented (n=25). Group 1: Control Group (CG), Group 2: Self Adjusting File (SAF), Group 3: XP-Endoshaper (XP), Group 4: TRUShape (TS), Group 5: V Taper 2H (VT). After instrumentation was completed, the roots were sectioned at 3 mm, 6 mm, and 9 mm from apex using a slow-speed circular saw. Digital images were captured using a 24× stereomicroscope by using a digital camera. Two operators independently checked each specimen for the presence of dentinal defects. Statistical comparison between the file systems was done using Chi-square (p<0.05). Result: There was no statistically significant difference in the frequency of microcracks between the groups of file systems (X2=4.509, p>0.05). VT file system exhibited higher microcracks (25%) but was not statistically significantly higher than XP (12%), TRUShape (12%), and SAF (4%) endodontic file systems. Conclusion: Within the limitations of this study, it can be concluded that all the file systems used in our research are minimally invasive files and produced few dentinal microcracks. VT files produced maximum while SAF produced the least number of micro-cracks.

Reinforcing an immature tooth model using three different restorative materials.

Background: To compare and evaluate the strength rendering capacity of three restorative materials in tooth model simulated as immature teeth. Materials and Methods: In this in vitro study, 80 human maxillary permanent central incisors scheduled for periodontal extraction were collected, and an immature tooth model was prepared using a 3 mm twist drill. To simulate single-visit apical barrier, all the teeth were prepared with peso number 1-6. The teeth were segregated into three experimental and a control group. The experimental groups (n = 20) comprised of fiber-reinforced composite (FRC), Biodentine, and glass ionomer cement. The fracture resistance of all the teeth was tested using universal testing machine. The final reading of the applied load to cause fracture was noted and later was subjected to statistical analysis, P ≤ 0.05 was considered statistically significant, and the level of significance was fixed at 5%. Student's t-test was applied to compare values among experimental groups. Results: There was a significant difference in the values of peak load resulting in fracture among experimental groups which was observed statistically (P ≤ 0.001). FRC exhibited superior reinforcing capacity (mean: 1199.7 N) among the experimental materials followed by Biodentine and Bioglass R. The lowest value to fracture was observed in control group (mean: 236.7 N). Conclusion: The results indicate that FRC could substantially contribute positively in reinforcing the simulated thin-walled immature roots.

Mechanical and antimicrobial property of different surface treated glass ionomer cements under desiccated condition.

BACKGROUND: The purpose of this in vitro study was to evaluate the effect of five different surface treatments on the mechanical property and antimicrobial effect of three desiccated glass ionomer cements. MATERIALS AND METHODS: In this in vitro experimental study, 300 rectangular blocks of three different restorative materials were fabricated using an aluminum mold, Group I (n = 100) Micron bioactive, Group II (n = 100) GC Fuji IX GP Extra, and Group III (n = 100) bioglass R. These blocks were stored in 100% humidity for 24 h and then placed in air to desiccate for another 24 h. These groups were further divided into two major groups (n = 50) for both mechanical (Flexural) and antimicrobial testing. The blocks of mechanical and antimicrobial groups were further divided into five subgroups (n = 10) based on the medias used for surface treatment (senquelNaF, MI varnish, chlorhex plus, kedodent mouthwash, and 100% humidity [control]). Flexural strength (FS) was measured using the universal testing machine. Fracture strength of groups was compared using the one-way analysis of variance and Tukey's post hoc test with P ≤ 0.05 considered statistically significant. Antimicrobial effect was carried out by covering the specimens in a suspension of Streptococcus mutans followed by incubation for 24 h. The blocks were later washed, vortex mixed, serially diluted, and plated. Ccolony-forming unit/ml was calculated after 3 days of incubation. Data were then analyzed using the Kruskal-Wallis and Mann-Whitney U nonparametric test, with P ≤ 0.05 considered statistically significant. RESULTS: Micron bioactive with the surface treatment of MI varnish significantly exhibited highest FS. Surface treatment of desiccated restorative materials with chlorhex plus exhibited no growth of S. mutans. GC Fuji IX GP Extra with surface treatment of MI varnish exhibited highest reduction in S. mutans growth compared to other experimental group. CONCLUSION: Surface treatment of restorative material with MI varnish improved their mechanical and antimicrobial property while among three restorative materials Micron bioactive showed better mechanical property, whereas GC Fuji IX GP Extra exhibited better antimicrobial property.

Radix entomolaris and radix paramolaris in mandibular molars: a case series and literature review.

The success of root canal treatment depends on complete debridement of pulp tissue from the root canals. Therefore, a thorough knowledge of unusual anatomical findings is of utmost importance. Although the majority of mandibular molars present with 2 roots (mesial and distal) and 3 or 4 root canals, the number of roots and root canals in individual molars may vary. An extra root is called a radix entomolaris if it is located distolingually and a radix paramolaris if located mesiobuccally. This article presents a series of 5 cases of radix entomolaris and radix paramolaris in mandibular first, second, and third molars and reviews the literature on these morphologic variations.