Aim To evaluate the effectiveness of five instruments used for irrigant agitation during the removal of calcium hydroxide [Ca(OH)2] paste in simulated internal root resorption (IRR) cavities created in extracted maxillary central incisors. Methodology Seventy maxillary central incisors with a single canal were selected. The canals were accessed and instrumented with Reciproc R50, then the roots were split in the bucco‐lingual direction and the halves separated. Simulated IRR cavities were created, in both halves of the roots, 5 mm from the apex with a spherical bur. The specimens were reconstructed with cyanoacrylate glue and allocated into seven groups: negative control – no treatment; positive control – filled with Ca(OH)2 without performing any irrigation protocol; the other groups were divided according to the instrument used for irrigant agitation, namely: Ultrasonic, EndoActivator®, EDDY®, XP‐endo® Finisher and XP‐endo® Shaper. The specimens were cleaved and analysed using optical microscopy and scanning electron microscopy, to compare the Ca(OH)2 remnants between them. Then, the IRR cavities created by the burs were cleaned and subjected to a protocol of demineralization with 20% nitric acid, the roots reconstructed, and the irrigant agitation methods, as well as the microscopic analysis was repeated. Analysis of the images of Ca(OH)2 remaining in the simulated IRR cavities after irrigation was performed by two calibrated examiners based on a previously established scoring system. The data were statistically compared by Kruskal–Wallis test, Mann–Whitney U‐test and Wilcoxon tests, with the significance level set at 5%. Results There was a significant difference in the effectiveness of the instruments in relation to the cavity creation method (bur vs. bur/acid) and evaluation method (optical microscopy and scanning electron microscopy) (P < 0.05). The XP‐endo® Finisher and EDDY® groups were associated with significantly more effective removal of Ca(OH)2 when the IRR cavities were created using the acid protocol and analysed by scanning electron microscopy. Conclusion None of the instruments tested were able to completely remove the Ca(OH)2 paste from the simulated IRR cavities; however, the EDDY® and XP‐endo® Finisher removed more Ca(OH)2 in the bur/acid cavity creation method analysed by scanning electron microscopy.

This article reports an uncommon case of talon cusp on a geminated permanent maxillary central incisor, including details of the clinical and radiographic findings and treatment. A 28-year-old woman presented at the university dental clinic, and intraoral examination revealed a maxillary central incisor of abnormal size with a prominent accessory cusp on the lingual aspect. The case was diagnosed as talon cusp on a geminated tooth. Early diagnosis of this anomaly is important since it may cause clinical problems such as esthetic concerns, caries and tooth crowding. In the present case, these anomalies did not complicate the subsequent endodontic treatment.

The success of endodontic therapy is based on good endodontic access, correct cleaning and shaping, and adequate root canal obturation. However, endodontic treatment is also dependent on a sound knowledge of the internal anatomy of human teeth, especially when anatomical variations are present. Certain anatomical changes may be present to varying degrees, and it is important to report these to improve the understanding and expertise of endodontic specialists. With this aim in mind, this study reports an example of a maxillary first molar showing unusual anatomy (four roots and six root canals) and describes the endodontic treatment that was employed.

This article describe a rare case of multiple taurodontism involving all molars in a 17-year-old male. Volumetric cone-beam computed tomography was used to investigate internal and external root morphology, including that of a maxillary first molar which required endodontic treatment and retreatment. Medical history was not contributory; however, Klinefelter syndrome was the diagnostic hypothesis in this case.

This paper presents a case report of a maxillary lateral incisor affected by invasive cervical resorption. The tooth was submitted to a 21-day treatment with calcium hydroxide followed by root canal filling. The area of resorption was sealed with MTA followed by glass ionomer cement and restored with composite resin. Two-year radiographic follow-up showed stability of the resorption site and normal coronal colour and depth of gingival sulcus.

The aim of this study was to evaluate the performance of undergraduates in their first contact with manual and rotary root canal instrumentation. Forty-two students who had never worked on a root canal before instrumented 42 extracted lower-incisors. Participants were assigned to one of two groups: Rotary instrumentation or manual instrumentation. Pre-and post-operative computed tomography scans were obtained with a 3-dimensional dental imaging system. Starting and finishing times of preparation were recorded. The cross-sectional area of the root canal was analyzed with 2-mm-belowthe-apex initial and final transverse images recorded through a digital imaging system and analyzed with software to measure the initial and final area of the root canal in mm 2 . Data from the cross-sectional area of the root canal and time spent were subjected to the Mann-Whitney's U-test (p<0.05). The rotary instrumentation group showed smaller time for preparation (p=0.0204). No differences between rotary and manual instrumentation regarding the cross-sectional area of the root canal were observed (p=0.25). No accidents occurred. Undergraduate students showed good performance in their first contact with the manual and rotary instrumentation with regard to time spent and cross-sectional area of the root canal, with no operative accidents.

This study investigated, if genetic variants in BMP2, BMP4 and SMAD6 are associated with variations in the palatal rugae pattern in humans. Dental casts and genomic DNA from 75 patients were evaluated. Each patient was classified as follows: total amount of rugae; bilateral symmetry in the amount, length and shape of the palatal rugae; presence of secondary or fragmentary palatal rugae; presence of unifications; predominant shape; and predominant direction of the palatal rugae. The genetic variants in BMP2 (rs1005464 and rs235768), BMP4 (rs17563) and SMAD6 (rs2119261 and rs3934908) were genotyped. Genotype distribution was compared between palatal rugae patterns using the chi-square test (alpha = 0.05). The allele A was associated with the presence of secondary or fragmentary rugae for rs1005464 (OR = 2.5, 95%CI 1.1–6.3; p = 0.014). Secondary or fragmentary rugae were associated with the G allele in rs17563 (OR = 2.1, 95%CI 1.1–3.9; p = 0.017). rs17563 was also associated with rugae unification (p = 0.017 in the additive model). The predominant shape (wavy) was associated with rs2119261 (p = 0.023 in the additive model). The left–right symmetry of the length of primary rugae was associated with rs3934908 in the recessive model (OR = 3.6, 95%CI 1.2–11.7; p = 0.025). In conclusion, genetic variants in the BMP pathway impacted on palatal rugae pattern.

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