Independent Root Canals Research Articles

Evaluation of the Quality of Canal Obturation Using the Continuous Wave Method after Shaping with Different NiTi Rotary Instruments by Micro-CT

Abstract Objective The aim of this article was to evaluate the influence of mesial root canal preparation of mandibular molars with the reciprocal systems (RCP) and self-adjusting file (SAF) in the incidence of voids spaces in endodontic obturation performed by modified continuous wave compaction (MCWC) technique, through images obtained in micro-computed tomography (micro-CT). Materials and Methods Mesial roots of 15 mandibular molars, with two independent root canals, were divided into three groups (n = 5/roots), according to the endodontic instrumentation strategy (RCP, SAF, and twisted file [TWF]). After the root canals (n = 10, for each instrumentation system) were filled with MCWC, images of each specimen were obtained by micro-CT followed by three-dimensional reconstruction. The percentage of voids was obtained (in mm3) in relation of the total volume, cervical–middle, and apical thirds. Statistical Analysis The data obtained were submitted to statistical analysis by Kruskal–Wallis and Dunn tests (p < 0.05). Results With respect to the total volume of root canal, TWF demonstrated a lower percentage in comparison to SAF (p < 0.05). No significant difference was obtained between TWF and RCP or RCP and SAF (p > 0.05). In the apical third, RCP showed a smaller percentage of voids when compared with SAF (p < 0.05); however, TWF demonstrated similarity with RCP and SAF (p > 0.05). The middle–cervical third exhibited no statistically difference between TWF and RCP or RCP and SAF (p > 0.05), whereas TWF was lower than SAF (p < 0.05). Conclusion Root canal preparation of mesial root of mandibular molars with TWF provides a lower incidence of voids in the endodontic filling performed by MCWC.

Effectiveness of three auxiliary irrigation methods for cleaning the internal walls of root canals of curved isolated teeth.

This study aimed to compare the effectiveness of ultrasound and acoustic and laser cleaning of curved root canals. A total of 92 molars with independent root canals with a curvature of 20°-40° were prepared and standardized at 04 25# and stained with gentian violet solution for 72 h. Among them, 52 were randomly divi-ded into four groups for final rinsing (n=13): NI group, PUI group, EDDY group, and PIPS group. Ten samples in each group were cut horizontally along the long axis perpendicular to the root and divided into curved upper, curved, and apical segments. Images were taken with a stereomicroscope and Image J measurements were taken to calculate the depth of rinse penetration. The remaining three samples from each group were split along the long axis of the dentin, photographed by scanning electron microscope to record the dentin tubule exposure and staining layer, and scored for staining layer by double-blind method. SPSS 26.0 software was used to perform statistical analysis and select the best flushing method. An extra 40 samples were randomly divided into four groups for detection of flushing fluid penetration depth (n=10): 10, 20, 30, and 40 s. In the upper part, the mean depth of infiltration was not significantly different between the experimental and control groups (P>0.05). The PIPS group had a significantly lower smear layer score than the control group and the EDDY group (P<0.01). In the curved segment, the mean depth of infiltration was significantly greater in the PUI group than in the control group (P<0.05); the tarnish layer score was lower in each experimental group than in the control group. At the top, the mean depth of infiltration was greater in the PUI and PIPS groups than in the control group (P<0.05), and the smear layer score was lower in the PIPS group than in the other groups (P<0.05). After the time was changed, the depth of infiltration of PUI increased only in the apical segment as the flushing time increased. The PUI and PIPS methods facilitate the penetration of irrigation solution into the dentin canal in curved root canals, especially in the apical segment. The PIPS technique is effective in removing the smear layer in curved root canals.

The antibacterial efficacy of photon-initiated photoacoustic streaming in root canals with different diameters or tapers

BackgroundIn recent years, the concept of minimally invasive endodontics has been proposed, which could be described as preventing or treating diseases by preserving more dental tissue and creating minimal damage. In the process of root canal preparation, it was recommended to use instruments with a smaller taper to preserve more tooth tissue and improve the preservation rate of the affected teeth. Photon-induced photoacoustic streaming (PIPS) was a new type of laser-activated irrigation technology, which was now widely used in endodontic treatment. The purpose of this article was to evaluate the bactericidal effect of PIPS with NaOCl in root canals with different widths or tapers.MethodsTwenty-three maxillary first molars with three independent root canals were included in this study. The mesiobuccal (MB), distobuccal (DB), and palatal (P) root canals were prepared at sizes of #10/.02, #25/.02, and #25/.06, respectively. After being incubated with a bacterial suspension for 4 weeks, the specimen were irrigated with 2% NaOCl activated by conventional needle irrigation (CNI) (n = 10) or PIPS (n = 10). Three specimen were not treated (control group). Before and after irrigation, the presence of bacteria was assessed with an adenosine 5'-triphosphate (ATP) assay kit and biofilms were assessed using confocal laser scanning microscopy and scanning electron microscopy.ResultsIn specimen prepared using PIPS irrigation, the ATP was reduced by more than 98%. When the root canal taper was 0.02, the size #25 root canals had a higher percentage of dead bacteria than the size #10 root canals in all regions (P < 0.05) in the PIPS group. When the root canal width was #25, the 0.02 taper group had a higher percentage of dead bacteria than the 0.06 taper group in the apical region (P < 0.05), except coronal and middle regions (P > 0.05). PIPS irrigation results in a greater percentage of dead bacteria and reduction of ATP in size #10/.02 root canals than CNI in size #25/.06 root canals in three regions (P < 0.05).ConclusionIncreasing the width from #10 to #25 improves the bactericidal effect of PIPS in the root canal. Increasing the taper of the root canal from 0.02 to 0.06 at size #25 did not affect the bactericidal effects of PIPS. PIPS resulted in more dead bacteria in specimen with smaller tapers and root canal widths than CNI. PIPS can be used to clean the smear layer in the coronal region and open the dentin tubules.Clinical significance: Activation of irrigants with PIPS brought about significant bacterial reduction smaller tapers and width root canals compared to CNI, which was beneficial to prevent excessive loss of tooth tissue and conserve the structural integrity of teeth.

Use of 3-dimensional–Printed Guide in Hemisection and Autotransplantation of a Fusion Tooth: A Case Report

Three-dimensional (3D)-printed guides have been used in endodontics to prepare a conservative access, locate calcified or missing canals, and perform precisive osteotomy in apicoectomy. Here, we present the treatment of a fusion tooth by combining 3D printing technology and endodontic intervention in a 10-year-old patient. The bifid crown of a maxillary right lateral incisor #7 had caused esthetic concerns and malocclusion. Clinical and radiographic examinations showed that #7 is fused with a supernumerary tooth with 2 independent root canals. The fusion involved the entire crown and the coronal and middle roots. Because of financial constraints, a multidisciplinary approach involving endodontic, orthodontic, and prosthodontic treatment was excluded. We hemisectioned the tooth intraorally with a 3D-printed guide, extracted the supernumerary tooth, and transplanted tooth #7 to a position with improved esthetics and occlusion. A 3D-printed tooth replica was used to prepare the recipient site for autotransplantation. At the 6-month follow-up, tooth #7 was diagnosed with pulp necrosis and asymptomatic apical periodontitis. Root canal treatment of tooth #7 was completed, and osseous healing was observed 8 months later. The patient had no clinical symptoms and was satisfied with the outcome 14 months after hemisection and transplantation. The open space between teeth #7 and #8 was closed without orthodontic treatment. We present an alternative option to treat a fusion tooth in young patients who do not opt for other treatment options because of their stage of development or for socio-economic reasons. Techniques in modern endodontics, such as cone-beam computed tomographic imaging and 3D printing, should be adapted when it is beneficial to patients.

Clinical and radiological assessment of the anatomical and topographic structure of the root canals of teeth in patients of different age groups

Was to identify the features of the anatomical structure of the root canals of teeth according to CBCT data in patients in different age groups. Patients of europeoid race, both sexes, who have indications for endodontic treatment (60 people), were divided into three groups: group 1 (young) 20 people aged 18 to 44 years, group 2 (middle age) 20 people - from 45 to 60 years, group 3 (elderly) 20 people - from 61 to 75 years old. To assess the root canal anatomy, all patients underwent x-ray examination (CT) on a Vatech computed tomography and analyzed with the Ez3D plus program before beginning endodontic treatment. The object of study was the first molars of the lower jaw (distal root canal). The analysis of axial, sagittal, coronal sections of the first molar of the lower jaw revealed that patients belonging to the 1st group, the distal root canal often had an oval shape all over (95%) and over a wide apical opening, in only one case out of 20 (5%) were identified at slit-like form of the distal root canal, probably due to malocclusion or as a consequence of increased abrasion of teeth. In group 2, two independent root canals were identified in the distal root of the first lower molar (in 65%), extending from the tooth cavity to the apex.in 35% of cases, the distal root canal began with a single entrance in the oral part and bifurcated into two separate channels at about the level of 2 /3 canals, then re - joined into a single apical opening, in group 3, in 75% of cases, a slit-like form of the distal root canal was observed. The obtained CLCT data (taking into account the image error) were confirmed in the clinic at the stage of endodontic treatment using optical magnification (microscope). CBCT and operation microscopy with x40 magnification data showed clear age-dependent variations of first lower molar distal root canal anatomy.

Palatal Radicular Groove Morphology of the Maxillary Incisors: A Case Series Report

IntroductionTeeth with a palatal radicular groove are challenging to diagnose, treat, and save. We classified this condition using cone-beam computed tomographic (CBCT) cross-sectional configurations combined with radiographic and morphologic observations during an intentional replantation procedure to identify and analyze the characteristics of palatal radicular grooves comprehensively as a reference for diagnosis, treatment planning, and prognosis evaluation of this condition. MethodsEight cases with palatal radicular grooves present in permanent maxillary incisors were investigated by radiography and CBCT imaging before intentional replantation. ResultsThe palatal radicular grooves were classified into 3 types based on groove depth and cross-sectional shape on CBCT images: type I, with a shallow groove depth, corresponding to a normal, simple, and single root canal; type II, with a medium groove depth, corresponding to a C-shaped canal system; and type III, with a deep groove depth, almost bisecting the root of the tooth, simultaneously present with 2 independent root canals and an apex with normal shape, corresponding to a labial groove connecting with a palatal groove. The extracted teeth and their radiographic images showed corresponding characteristics. ConclusionsThe CBCT cross-sectional images allowed the best visualization of the depth of the grooves and highlighted the difficulties entailed in treating such teeth. Intentional replantation is an effective therapeutic decision for this type of deformity and can provide better prognosis estimation, especially in teeth with type II and III grooves.

Prevalence of Root Fusions and Main Root Canal Merging in Human Upper and Lower Molars: A Cone-beam Computed Tomography In Vivo Study

IntroductionComplex root canal systems appear regularly on fused roots. The aim of this observational study was to evaluate the prevalence of fused roots and root canal merging in the first and second upper and lower permanent molars by using cone-beam computed tomography technology. MethodsA large sample of cone-beam computed tomography examinations was accessed. Maxillary and mandibular molars were classified according to number of roots, root fusions, types of root canal system configurations, merging positions, and merging levels. The Z test for proportions was used to analyze the differences in independent groups. A value of P < .05 was considered significant. ResultsThis study included 4120 molars. The prevalence of root fusions was 7.1% and 25.2% for the first and second upper molars, respectively; for the first and second lower molars, the prevalence was 0.7% and 12.6%, respectively. In addition, 8.6% and 10.1% of the second upper and lower molars, respectively, had fused roots with canal merging; moreover, 7.1% and 2.1% of the second upper and lower molars had single or 2 non-merging root canals, respectively. The most usual merging position for the first upper molars is between the distobuccal root and palatal root canals; for the second upper molars, the most usual merging position is between the mesiobuccal root and distobuccal root canals. Merging appears more commonly at the apical level. Significant differences were found between the teeth and gender groups. ConclusionsWhen approaching the second upper and lower molars, the clinician should be aware of uncommon morphologies. In our sample, 15.7% and 12.2% of the second upper and lower molars, respectively, had fused roots, which did not present the usual configurations with independent root canals.

Micro-Computed Tomographic Evaluation of 2 Nickel-Titanium Instrument Systems in Shaping Root Canals

IntroductionCleaning and shaping without making procedural errors have always been a challenge in endodontics, particularly when the root canals are curved. Several rotary instruments have been developed to minimize such errors. The purpose of this study was to compare the shaping ability of 2 rotary file systems, BioRace (BR; FKG, La Chaux-de-Fonds, Switzerland) and ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), during the preparation of curved root canals in extracted teeth using micro–computed tomographic imaging. MethodsA total of 20 first and second human mandibular molars with 2 separate mesial canals were scanned before and after root canal preparations using the SkyScan 1176 X-ray microtomograph (Bruker microCT, Kontich, Belgium) at a resolution of 17.42 μm. Canals were prepared using the BR and PTN systems. The percentage of dentin removed after preparation, root canal volume increase, untreated canal walls, structure model index, degree of canal transportation, and centering ability were also measured. ResultsThere were no significant differences between the 2 groups in the removed dentin after preparation and determination of the root canal volume, percentage of untreated canal walls, structure model index, degree of canal transportation, and centering ability (P > .05). ConclusionsIn conclusion, within the limitations of this ex vivo study, instrumentation of moderately curved mesial roots with 2 independent root canals and foramina using the BR and PTN rotary file systems were equally effective. Both instrumentation systems caused negligible procedural errors with minimal apical transportation.

A Central Incisor with 4 Independent Root Canals: A Case Report

The maxillary central incisor is the tooth with the least anatomic variations. Despite the fact that several studies have reported a prevalence of 100% for the presence of a single canal, root canal aberrations of maxillary central incisors with up to 3 canals have also been reported. Such cases represent both a diagnostic and technical challenge to the clinician. The present case describes root canal treatment performed in a maxillary central incisor with 4 canals. The detection of all canals was achieved by examination of the pulp chamber floor with the help of the dental operating microscope as well as careful examination of intraoral radiographs. The canals were prepared with hand and rotary instruments and obturated with a warm gutta-percha technique. The present report is the first to describe a maxillary central incisor with 4 canals in a tooth with no developmental abnormalities. It stresses the importance of using a dental operating microscope during endodontic treatment as well as questioning the routine use of cone-beam computed tomographic imaging for similar cases.

Accumulated Hard Tissue Debris Produced during Reciprocating and Rotary Nickel-Titanium Canal Preparation

IntroductionThis study compared the amount of hard tissue debris produced after different apical enlargement with single-file reciprocating systems (WaveOne [Dentsply Maillefer, Baillaigues, Switzerland] and Reciproc [VDW, Munich, Germany]) and a conventional multifile rotary system (BioRaCe [FKG Dentaire, La-Chaux-de-Fonds, Switzerland]) using micro–computed tomographic imaging. MethodsThirty moderately curved mesial roots of mandibular molars presenting 2 independent root canals were selected and scanned at an isotropic resolution of 14.16 μm. The sample was assigned to 3 groups (n = 10) with respect to the root length and degree of curvature of the mesial root according to the system used for the root canal preparation: Reciproc, WaveOne, and BioRaCe. Second and third scans were taken after the root canals were prepared up to ISO sizes 25 and 40, respectively. The matched images of the mesial canals, before and after preparation, were examined from the furcation level to the apex to evaluate the amount of hard tissue debris (%). Data were statistically compared using a general linear model for repeated-measures with a significance level set at 5%. ResultsInstrumentation systems per se did not influence the amount of hard tissue accumulation (P > .05), whereas a significant reduction in the percentage of hard tissue debris was observed after sequential enlargement in all groups (P < .05). ConclusionsNone of the systems yielded root canals completely free from packed hard tissue debris. The increased final apical size resulted in significantly less debris accumulation for both reciprocating and rotary systems.

A fused maxillary central incisor and its multidisciplinary treatment: an 18-year follow-up.

Fused teeth may cause aesthetic, spacing, periodontal, eruption, and caries problems. The present case report describes a 7-year-old boy patient with a chief complaint of unerupted maxillary incisor. Radiographic examination indicated a fused tooth which had two fused roots but two independent root canals. A complex management of a fused tooth is really difficult to standardize. In this case an orthodontic, endodontic, and surgical treatment (intentional replantation) allowed the tooth to be retained until 18 years following intervention. Maintenance of the root and alveolar bone in young adults at least until full skeletal maturation should be the main treatment objective.

Root canal treatment of bilateral three-rooted maxillary first premolars

In endodontics, several anatomic variations occur in teeth, both externally and in the internal root morphology, which play a very significant role in the diagnosis and treatment outcome. A thorough knowledge of the root canal anatomy, careful interpretation of the angled radiographs, proper endodontic access cavity preparation, and exploration of the root canal are the prerequisites for endodontic success. In a maxillary first premolar, it is rare to find extra roots and canals, and the aim of the present article is to report a case about the successful diagnosis and clinical management of bilateral three-rooted maxillary first premolars, with three independent root canals.

Identification of Independent Middle Mesial Canal in Mandibular First Molar Using Cone-Beam Computed Tomography Imaging

Introduction The root canal treatment of a mandibular molar with aberrant canal configuration can be diagnostically and technically challenging. Methods This case report presents the clinical management of a mandibular first molar with three separate mesial canals including middle mesial canal, which was confirmed by cone-beam computed tomography (CBCT) images. Results Posttreatment images revealed three independent root canals in the mesial root obturated efficiently to the accepted lengths in all three canals. Conclusion This case report highlights the usefulness of CBCT imaging for accurate diagnosis and management of the unusual canal morphology.

Gingival abscess occurring in maxillary primary central incisor fused to supernumerary tooth

A 5Y7M-old girl was referred to our clinic by a general dentist for detailed examination of a recurrent gingival abscess in the maxillary left primary central incisor region. An intraoral examination revealed a diffuse swelling in the palatal gingiva area of the affected tooth. A periapical radiograph showed that the affected tooth was actually the primary central incisor and a supernumerary tooth, which had fused and been filled with composite resin at the juncture of the 2 tooth crowns. Removal of the filling induced severe bleeding and root canal treatment was performed. Radiographic examinations revealed 2 independent root canals, thus an additional access cavity to the mesial pulp cavity was produced for further root canal treatment. After the lesion had disappeared, root canal filling was performed using iodoform-calcium hydroxide paste and the affected tooth was restored with composite resin to fashion a single crown. However, the canal filling paste was later observed to be resorbed in the cervical area of the root. At 6Y0M, the patient received a traumatic injury in the anterior teeth region and the fused tooth was drastically displaced in a palatal direction, thus we extracted it under infiltration anesthesia. The root was observed to be wide in the mediodistal direction, and a histopathological examination revealed only dentin between 2 independent root canals. Our findings showed that the fused tooth was composed of 2 crowns and 1 root with 2 independent canals, and indicate that each crown and canal should have been treated separately.