Guided Endodontics in Complex Scenarios of Calcified Molars

This study aimed to report a case series and describe the use of guided endodontics in complex symptomatic cases of mandibular and maxillary molars; presenting calcification of all three root canals. The arches of the referred patients were scanned, and high-resolution cone-beam computed tomography (CBCT) imaging was performed. Then, the taken CBCT and tooth scans were aligned and processed using software. A virtual copy of a drill was superimposed onto the scans and evaluated in 3 dimensions. Subsequently, a 3-dimensional (3D) template was designed and printed. Drilling was performed and a radiograph was taken to confirm its position. The canals were reached and endodontic treatment was performed. At the 12-month follow-up, the teeth were completely asymptomatic. The use of guided endodontics _in cases of calcification in molars_ was demonstrated to be a viable and reliable alternative treatment. The technique was based on 3D planning.Keywords: Access Opening; Apical Periodontitis; Dental Trauma; Guided Endodontics; Pulp Canal Calcification

Cyclic flexural fatigue resistance of NiTi Controlled Memory and Blue Technology instruments after torsional preloading

Objective: The aim of this study was to evaluate the influence of torsional preloading on the cyclic flexural fatigue resistance of thermally treated NiTi instruments. Material and Methods: Ten new instruments New Hyflex CM (HF 30.06; Coltene/Whaladent Inc.), Typhoon CM (TYP 30.06; Clinician's Choice Dental Products) and Vortex Blue (VB 30.06; Dentsply Tulsa Dental) were chosen, based on geometry and specific characteristics of the manufacturing process. The new instruments of each system were tested in a bench device to determine their fatigue resistance through mean value of number of cycles to failure (Nf) (Control Group – CG). Another group of 10 new HF, TYP and VB instruments were submitted to 20 cycles of torsional straining between 0° and 180° (Experimental Group – EG) and then submitted to fatigue until rupture under the same conditions of the CG. Tested instruments were examined by scanning electron microscopy (SEM). Data were analyzed using one-way analysis of variance and post hoc Tukey’s test (α=.05). Results: Higher fatigue resistance was accomplished by HF instruments, followed by VB and TYP (p<0.05). During the torsional preloading, the lowest mean torque value was observed for TYP instruments (p<0.05). The torsional preload caused a significant reduction in the Nf values (p<0.05) of about 20%, 39% and 45% for instruments HF, VB and TYP, respectively. Longitudinal cracks, generated during the torsional preloading, were present in VB files, but were not observed in the CM instruments (HF and TYP). Conclusions: In conclusion, the flexural fatigue resistance of thermally treated instruments is diminished after cyclic torsional loading

Behavior of nickel-titanium instruments manufactured with different thermal treatments.

INTRODUCTION: The purpose of this study was to investigate if nickel-titanium instruments with similar designs manufactured by different thermal treatments would exhibit significantly different in vitro behavior. METHODS: Thirty-six instruments each of ProTaper Universal (PTU F1; Dentsply Maillefer, Ballaigues, Switzerland), ProFile Vortex (PV; Dentsply Tulsa Dental Specialties, Tulsa, OK), Vortex Blue (VB, Dentsply Tulsa Dental Specialties), and TYPHOON Infinite Flex NiTi (TYP; Clinician\u27s Choice Dental Products, New Milford, CT) (all size 25/.06) were evaluated. Bending resistance, torsion at failure, and dynamic torsional tests were performed with the instruments (n = 12). Analysis of variance and Tukey post hoc tests were applied. RESULTS: Flexibility was significantly higher for TYP compared with the other 3 groups (P \u3c .0001). With respect to the maximum torque at failure, PV group showed the highest resistance to twisting (torsional strength) among the analyzed instruments followed by VB, TYP, and PTU. The TYP group exhibited greater angular deflection at failure compared with the other groups (P \u3c .0001). The mean dynamic torque scores during simulated canal preparation were highest for TYP (3.01 ± 0.71 Ncm) and lowest for PV (1.62 ± 0.79 Ncm). However, no significant differences were observed comparing groups PTU with TYP and VB and VB with PV (P \u3e .05). The highest mean forces were recorded with PTU (7.02 ± 2.36 N) and the lowest with TYP (1.22 ± 0.40 N). CONCLUSIONS: TYP instruments were significantly more flexible than the other instruments tested. The PV group had the highest torsional strength and TYP, despite being the most flexible, showed similar torsional moments to the other instruments, whereas its angular deflection was the highest among the groups

Cyclic flexural fatigue resistance of NiTi Controlled Memory and Blue Technology instruments after torsional preloading

Abstract Objective The aim of this study was to evaluate the influence of torsional preloading on the cyclic flexural fatigue resistance of thermally treated NiTi instruments. Material and Methods Ten new instruments New Hyflex CM (HF 30.06; Coltene/Whaladent Inc.), Typhoon CM (TYP 30.06; Clinician's Choice Dental Products) and Vortex Blue (VB 30.06; Dentsply Tulsa Dental) were chosen, based on geometry and specific characteristics of the manufacturing process. The new instruments of each system were tested in a bench device to determine their fatigue resistance through mean value of number of cycles to failure (Nf) (Control Group – CG). Another group of 10 new HF, TYP and VB instruments were submitted to 20 cycles of torsional straining between 0° and 180° (Experimental Group – EG) and then submitted to fatigue until rupture under the same conditions of the CG. Tested instruments were examined by scanning electron microscopy (SEM). Data were analyzed using one-way analysis of variance and post hoc Tukey’s test (α=.05). Results Higher fatigue resistance was accomplished by HF instruments, followed by VB and TYP (p<0.05). During the torsional preloading, the lowest mean torque value was observed for TYP instruments (p<0.05). The torsional preload caused a significant reduction in the Nf values (p<0.05) of about 20%, 39% and 45% for instruments HF, VB and TYP, respectively. Longitudinal cracks, generated during the torsional preloading, were present in VB files, but were not observed in the CM instruments (HF and TYP). Conclusions In conclusion, the flexural fatigue resistance of thermally treated instruments is diminished after cyclic torsional loading

Guided tissue regeneration in class IV external cervical resorption: A case report

External cervical resorption (ECR) is a type of dental resorption that originates from the loss of the cementum's protective layer. The direct exposure of dentin to the periodontal ligament may lead to the invasion of clastic cells through an entry point on the external root surface into the dentinal tissue, causing resorption. Depending on the extension of ECR, different treatments are proposed. Although the literature presents distinct materials and methods for restoring ECR areas, an existing gap is related to care in the treatment of the supporting periodontal tissue. Guided tissue regeneration/guided bone regeneration (GTR/GBR) includes the stimulation of bone formation in bone defects using different types of membranes (resorbable and non-resorbable), regardless of its association with bone substitutes or grafts. Despite the benefits of guided bone regeneration, the application of this method in cases of ECR is still under-explored in the literature. Thus, the present case report uses GTR with xenogenic material and polydioxanone (PDO) membrane in a case of class IV ECR. The success of the present case is related to the correct diagnosis and treatment plan. Complete debridement of resorption areas and restoration with biodentine were effective in tooth repair. GTR contributed to the stabilization of supporting periodontal tissues. The association of the xenogeneic bone graft with the PDO membrane proved to be a viable option for restoring the health of the periodontium