Cone-beam Computed Tomographic and Micro–computed Tomographic Evaluations of the Root Apexes of Teeth with Posttreatment Apical Periodontitis

IntroductionThis study evaluated the association of different variables that may influence the outcome of root canal treatment through cone-beam computed tomographic (CBCT) and micro–computed tomography (micro-CT) assessments of root apexes obtained by endodontic microsurgery of teeth with posttreatment apical periodontitis (AP), the agreement between CBCT and micro-CT findings, and the association of these variables with symptoms or lesion size.MethodsClinical and CBCT records and root apexes obtained by endodontic microsurgery from 11 cases of symptomatic AP and 22 cases of asymptomatic AP were available. Apical root specimens were further scanned using micro-CT imaging. CBCT parameters included periapical radiolucency size, apical extent/density of root canal filling, and occurrence of procedural errors. Micro-CT images evaluated the same parameters plus the presence of filling material in lateral canals and ramifications, the volume of the filled/nonfilled apical root canal, and the percentage of the nonfilled canal space. The agreement between CBCT/micro-CT observations was evaluated.ResultsMandibular teeth, a lesion size <5 mm, a nonfilled volume <0.04 mm³, and the decreased percentage of the nonfilled canal volume were significantly associated with symptomatic AP. Maxillary teeth and inadequate apical filling density were significantly associated with larger lesions. Agreement between CBCT/micro-CT scores varied from fair (procedural errors) to satisfactory (extent/density of filling).ConclusionsTooth location, lesion size, the nonfilled apical canal volume, and the percentage of the nonfilled apical canal volume were associated with symptomatic AP. In addition, lesion size was significantly associated with tooth location and apical root canal filling density. CBCT imaging may not provide a reliable evaluation of procedural errors associated with posttreatment disease.     

The quality of root canal treatment and periapical status of permanent teeth in Turkish children and teens: a retrospective CBCT study

Objective

This study aimed to assess the quality of root canal fillings and the prevalence of periapical radiolucencies in the permanent teeth of 6–18 year-old Turkish children.

Methods

CBCT images of 150 patients’ 235 teeth with a mean age of 16.0?±?2.06 years were included. Root development stage, quality of root canal filling, the presence and severity of periapical radiolucencies, and their relationship with anatomical structures were recorded. Correlations between the quality of root canal filling, periapical lesion, and lesion size were assessed using regression analyses.

Results

A total of 235 teeth (528 root canals) were evaluated. 65.5% of root canals had periapical lesions. Immature roots and mandibular teeth had the highest prevalence and the largest size of periapical radiolucencies (p?<?0.05). Overfilling (n?=?52), underfilling (n?=?93), unfilled (n?=?46), inhomogeneously filled (n?=?113) root canals and poor coronal restoration (n?=?85 teeth) were observed in terms of technical failures of endodontic treatment. The quality of endodontic treatment was associated with the presence of periapical lesion and lesion size (p?<?0.05). Teeth with under-filled, overfilled or inhomogeneously filled root canals and poor coronal restoration had a periapical lesion larger than 5 mm (p?<?0.05). Immature teeth were most associated with the presence of lesion (OR?=?4.07) and the lesion size?>?5 mm (OR?=?3.71).

Conclusion

The prevalence of periapical radiolucencies in young permanent teeth showed an increase when the tooth was an incisor, had incomplete root development, or the root filling had technical errors.

     

The imaging of root canal obturation using micro-CT

AIM: To examine the potential and accuracy of micro-computed tomography (micro-CT) for imaging of filled root canals. METHODOLOGY: The root canals of five extracted maxillary teeth were shaped manually with K-files. After irrigation and drying, the root canals were filled by lateral condensation using gutta-percha cones and AH plus (Dentsply Maillefer, Ballaigues, Switzerland) as sealer. The filled root canals were examined by micro-CT at resolutions <11 microm. Three-dimensional reconstructions of the root canal fillings were made. The roots were sectioned histologically and standard photographs of the sectioned surfaces were taken. Digitized photographic images and the corresponding micro-CT sections were correlated qualitatively by superimposition. Quantitative morphometric data were obtained with respect to the surface area of the root canal filling and the individual gutta-percha points of the histological and the micro-CT sections. Pearson correlation coefficients were calculated. RESULTS: There was a good qualitative correlation between the images from the histological and the micro-CT sections. The fillings were clearly differentiated from the root canal walls. Individual gutta-percha cones and sealer were discernable. Pearson correlation coefficients showed a highly significant correlation between the two methods (P < 0.001) with respect to the area of the complete root canal filling (r = 0.992) and the gutta-percha cones (r = 0.968). CONCLUSIONS: The micro-CT technique was a highly accurate and nondestructive method for the evaluation of root canal fillings and its constituents. Qualitative and quantitative correlation between histological and micro-CT examination of root canal fillings was high.     

Evaluation of different root canal filling techniques in severely curved canals by micro-computed tomography

AimTo fill the severely curved root canals with different filling techniques and to compare these techniques using micro-computed tomography (micro-CT).Materials and methodsSixty extracted mandibular first molars (degree of root canal curvature >25°) were selected. All samples were divided into four groups and filled with one of the following techniques: lateral condensation, single-cone, continuous-wave obturation, and core carrier. After they were scanned by micro-CT, the total area, filled area and void area of the root canal were calculated. The Mann–Whitney U and Kruskal–Wallis tests were used for statistical analysis (p < 0.05).ResultsIt was shown that significantly more filling material was used in the lateral condensation and core carrier technique groups at 2 and 5 mm than in the single-cone and continuous-wave obturation technique groups (p < 0.05). It was observed no statistically significant difference at 8 mm (p > 0.05).ConclusionNo technique could completely fill in root canal. Regarding the coronal part, all techniques can be used for more effective filling as long as a good condensation is achieved. The use of a plugger with an optimal size according to the localisation of root canal curvature and the choice of a heat-resistant root canal sealer affects the success of the treatment in the thermoplastic techniques.     

The Influence of Missed Canals on the Prevalence of Periapical Lesions in Endodontically Treated Teeth: A Cross-sectional Study

IntroductionUntreated root canals may have a direct impact on the prognosis of root canal treatment. The objective of this cross-sectional study was to evaluate the association of missed canals with periapical lesions in endodontically treated teeth.MethodsOne thousand one hundred sixty preexisting cone-beam computed tomographic scans from 8 different health centers were assessed between January 2018 and December 2018 by 5 independently calibrated observers. Two thousand three hundred five endodontically treated teeth were identified in a sample of 20,836 teeth (27,046 roots). All endodontically treated teeth were evaluated for the presence or absence of missed root canals and periapical lesions. The z test for proportions was used to analyze differences between groups, and an odds ratio was calculated in order to analyze the association between missed canals and lesions. P < .05 was considered statistically significant.ResultsThe prevalence of missed canals was 12.0%, and teeth with untreated canals were associated with periapical pathology in 82.6% of the cases. The root presenting with the highest percentage of missed canals (62.8%) was the mesiobuccal root of the maxillary first molar, being associated with periapical lesions in 75.2% of cases. Maxillary molar mesiobuccal roots presenting with a missed canal were 3.1 times more likely to be associated with periapical pathology than maxillary molars with all canals identified and treated.ConclusionsThe association between untreated root canals and the presence of periapical lesions noted in the present study shows that missed canals have a significant impact on treatment prognosis.     

Comparative evaluation of cone beam CT and micro-CT on blooming artifacts in human teeth filled with bioceramic sealers

Aim

To assess blooming artifacts caused by root canal sealers in CBCT images compared with those that appeared in micro-CT scan images used as references.

Materials and method

Thirty freshly extracted human mandibular central incisors were used. Root canals were prepared with nickel titanium files with an ISO size 40/0.06 taper and filled with a single cone (40/0.06 taper) and three different sealers. The samples were divided into the following three groups with 10 roots each: (I) AH Plus sealer; (II) Sure Seal Root; and (III) Total BC sealer. Teeth were scanned with the same voxel sizes (0.2 mm) in different CBCT devices and the micro-CT images were acquired as reference images.

Results

Significantly different results in terms of blooming artifacts were detected between CBCT and micro-CT images, as well as among the CBCTs images. The canals filled with AH Plus sealer showed more blooming artifacts than those filled with bioceramic sealers (p < 0.05). Additionally, the worst blooming artifact was observed when the images were acquired with lower kilovoltage peak.

Conclusion

The appearance of blooming artifacts is dependent on sealer and CBCT, and their effects are significantly worse than they are in micro-CT images. The differential effect of different sealers and distinct CBCT protocols should be further investigated to enable the use of bioceramic sealers without a significant impact on post-treatment imaging.

Clinical relevance

Root canal sealers showed a different extent of blooming artifact in CBCT images. Hence, researchers and clinicians should be aware of these artifacts before conducting endodontic evaluations using CBCT images.

     

An Automated Measurement Method for the Endodontic Working Width of Lower Molars by Means of Parametric Models Using Cone-beam Computed Tomographcy and Micro–Computed Tomography

IntroductionA new method for the approximation of the root canal's cross-sectional shape and its working width using cone-beam computed tomographic (CBCT) or micro–computed tomographic (micro-CT) imaging was introduced.MethodsScanned data from 29 extracted human mandibular first and second molar distal root canals without instrumentation were reconstructed and analyzed with a self-developed measurement algorithm. The 3-dimensional volume models were sliced perpendicular to the vertical axis. Using different 2-dimensional parametric models, the contour of each root canal slice was approximated and used to determine the canal's cross-sectional dimensions. The measurements of minor width, major width, and the root canal's conicity were statistically analyzed using analysis of variance.ResultsThe measured minor and major widths of the investigated root canals were significantly higher (probability value P < .05) when evaluated by CBCT images than the results obtained from micro-CT data. Both dimensions increased starting from the apical foramen (P < .01). The narrowest measured canal widths were 0.19–0.24 mm for CBCT imaging and 0.09–0.21 mm for micro-CT imaging in the apical part. The maximum values for conicity were between 13% and 17% in the cervical third.ConclusionsThe 3-dimensional imaging data from CBCT and micro-CT imaging enabled a valuable anatomic assessment of the root canal's cross-sectional working width along the canal up to the physiological foramen in order to determine an adequate apical diameter as well as the correct measured taper in the cervical and medial part.     

Influence of Length of Root Canal Obturation on Apical Periodontitis Detected by Periapical Radiography and Cone Beam Computed Tomography

IntroductionThe verification of the best length of root canal instrumentation and obturation still is controversial theme in endodontics. The purpose of this study was to determine the influence of length of root canal obturation on apical periodontitis (AP) detected by periapical radiography and cone beam computed tomography (CBCT).MethodsA total of 503 root canal obturations were evaluated by using periapical radiography and CBCT. Distances from the radiographic apex to the tip of filling material were measured and classified as close to 2 mm, 1 mm short or beyond apex, and at the apex. Obturations at the apex were associated with AP. Odds ratio, confidence intervals, and χ² test were used for statistical analyses.ResultsPeriapical radiographs showed that root canal obturations were 1–2 mm short of the apex in 88%, 89.3%, and 95% of the anterior teeth, premolars, and molars, respectively. CBCT images showed obturations had the same length in 70%, 73.7%, and 79% of anterior teeth, premolars, and molars, respectively. The frequency of AP was significantly greater in molars than in the other tooth groups, regardless of diagnostic method. AP was detected more frequently when CBCT was used.ConclusionsAP was detected at all lengths of root canal obturation. The analyses of diagnostic methods showed that AP was detected more frequently when CBCT was used.     

210例根管治疗失败病例的根尖X线片和锥形束CT的影像学分析

[摘要]目的：比较根尖X线片（periapical radiograph, PR）与锥形束CT（cone-beam computed tomography, CBCT）在诊断根管治疗（root canal treatment, RCT）失败病例时的差异。方法：回顾性分析RCT失败患牙的影像学资料,比较PR与CBCT诊断RCT失败病例的病因和病情时的差异。结果：共分析210颗RCT失败患牙的PR和CBCT资料,根管欠填和遗漏根管是导致RCT失败的主要原因。CBCT能更准确的判断根管充填质量和根折类型,CBCT对遗漏根管的检出率比PR高14.8%,对根折的检出率比PR高5.7%。结论：CBCT对RCT失败病例的病因和病情分析优于PR,能为根管再治疗的方案制定提供更有意义的参考。     

Effect of the Periapical “Inflammatory Plug” on Dental Pulp Regeneration: A Histologic In Vivo Study

IntroductionIn the current study, we investigate the effect of the inflammation occupying the apical foramen—a phenomenon we refer to as “inflammatory plug”—on the regenerative potential of a root canal therapy.MethodsWe performed root canal treatment (RCT) in 12 canine root canals while aseptically instrumenting the apex to a 0.5-mm-wide foramen and obturating the canals with the following materials: collagen sponge, platelet-rich fibrin, and blood clot (no material introduced).ResultsWe were successful in maintaining the integrity of the periapical tissue in 8 of 12 RCTs. Injury to the periapical tissue occurred during the remaining 4 RCTs, which initiated inflammation accompanied by bone and dentin resorption. Our histologic analyses showed that the resulting inflammatory plug contained abundant M1 macrophages and was associated with an absence of intracanal cellular infiltration. On the contrary, noninflamed samples showed signs of repair, as indicated by the migration of periapical cells throughout the root canal.ConclusionsWe conclude that controlling periapical inflammation is key while attempting to achieve dental pulp regeneration.     

自固化磷酸钙根管充填材料治疗成人根端开放恒牙的疗效评价

目的 评价自固化磷酸钙根管充填材料治疗成人根端开放伴根尖周病恒牙的临床疗效。方法 选择39颗成人根端开放伴慢性根尖周炎的患牙,在完成根管预备和消毒后,将自固化磷酸钙根管封闭剂充填于根管内,至根尖完全封闭后进行永久根充,治疗后每隔3个月复查1次,随访1年进行疗效评价,将患者年龄、根尖发育程度与预后进行统计学分析。结果 39颗患牙治疗后随访1年,总有效率为87.2%,患者年龄大,患牙病变持续时间长、根尖发育程度差,则根尖达到生理性封闭越困难。结论 自固化磷酸钙可以作为根尖诱导技术的一种可选材料,用于治疗成人根端开放伴慢性根尖周炎的恒牙有一定疗效,但远期疗效有待进一步观察。     

Evaluation of Passive Ultrasonic Irrigation and GentleWave System as Adjuvants in Endodontic Retreatment

IntroductionNonsurgical endodontic retreatment continues to be a challenge in endodontics, particularly when dealing with a complex tooth anatomy. This study evaluated the efficacy of passive ultrasonic irrigation (PUI) and the GentleWave system as supplementary techniques to remove remaining filling materials from oval-shaped root canals.MethodsTwenty distal roots of human mandibular molars with single and oval-shaped canals were shaped with R40 (40.06) instrument and filled with gutta-percha and AH Plus sealer using warm vertical obturation. Initial filling material removal was performed with R50 (50.05) instrument, followed by the use of PUI (n = 10) or GentleWave system (n = 10). Micro-computed tomographic images were obtained after obturation, initial material removal, and after the use of PUI and GentleWave. The volume of remaining filling material was calculated for the entire canal as well as for the coronal, middle, and apical thirds. Statistical analyses were performed by using analysis of variance, Kruskal-Wallis and Mann-Whitney tests. P ≤ .05 was considered significant.ResultsThe use of PUI and GentleWave as supplementary techniques significantly reduced the volume of remaining filling material after initial instrumentation (P < .05). However, none of these techniques was able to render canals free from filling materials. PUI showed better performance by removing 18% of the remaining filling material, whereas the GentleWave system was able to remove approximately 10% (P = .02).ConclusionsThe use of supplementary techniques optimized filling material removal after initial instrumentation. PUI enhanced the overall cleaning of the root canal system during endodontic retreatment in oval-shaped canals.     

Planned Apical Preparation Using Cone-Beam Computed Tomographic Measures: A Micro-Computed Tomographic Proof of Concept in Human Cadavers

IntroductionThis study assessed the amount of unprepared surface areas at the apical 4-mm segment of the root canal after a planned preparation based on cone-beam computed tomography (CBCT) measurements.MethodsEighteen posterior mandible segments were obtained from cadavers and scanned using CBCT and micro-computed tomographic (micro-CT) imaging. CBCT images were used to measure the largest initial canal diameter from 29 root canals of premolars at 1, 2, 3, and 4 mm short of the apical foramen. Each measurement was used to select a master apical instrument with size/taper that was 1 diameter larger to prepare the apical 4 mm of each particular root canal. A post-preparation micro-CT scan was obtained, and the unprepared canal areas were calculated.ResultsA very high amount of surface areas over the apical 4 mm of the root canal was included in the final preparation (mean >90%). The unprepared areas ranged from as low as 3.7% to a maximum of 14.6% (mean and median, 9.2% and 9.1%, respectively).ConclusionsThe proposed planned apical root canal preparation resulted in optimized root canal shaping with a substantial amount of prepared surface areas. The protocol used also resulted in a conservative canal enlargement using final instruments that were 1 size larger than the initial largest canal diameter.     

华东地区汉族人下颌第一前磨牙根管弯曲度的测量

目的 采用显微CT精确测量下颌第一前磨牙根管的弯曲度,为临床根管治疗提供依据。方法 收集华东地区汉族人154颗离体下颌第一前磨牙并进行显微CT扫描,采用Mimics 10.01（Materialise,Leuven,比利时）对牙齿及根管系统进行三维重建,在平行投照模式下,采集根管系统颊面观及邻面观的影像并测量根管的弯曲度。结果 下颌第一前磨牙单根管在颊面观上初次弯曲的平均角度仅为11.1°（Schneider法）,二次弯曲出现率较低,在颊面观出现6例,邻面观出现4例。下颌第一磨牙双根管时,重度弯曲（>20°）主要位于邻面观,颊、舌根管初次弯曲的平均角度分别为17.5°和28.7°,二次弯曲的发生率分别为19.1%（9/47）和85.1%（40/47）。舌侧副根管的弯曲半径和圆心角均值分别为6.6 mm和54.2°;舌侧根管的根管口离根尖的平均距离为6.6 mm。结论 下颌第一前磨牙舌侧根管多出现在根中及根尖1/3,在邻面观常有重度弯曲。     

Retreatment of Root Canals Filled with BioRoot RCS: An In Vitro Experimental Study

IntroductionThe purpose of this study was to compare the speed of removal of root canal filling material and re-establishment of apical patency in root canals filled with a tricalcium silicate–based sealer (BioRoot RCS [BRCS]; Septodont, Saint-Maur-des-Fossés, France) versus a zinc oxide–eugenol sealer (Pulp Canal Sealer [PCS]; Sybron Endo Kerr, Orange, CA) and to analyze the effect of the operator’s experience.MethodsOne hundred twenty root canals of 40 Dentalike dental simulators (Dentsply Sirona, York, PA) were shaped with a WaveOne (Dentsply Sirona) reciprocating file using short 3-mm strokes. Root canals were obturated using a single gutta-percha cone and either BRCS or PCS. Samples treated either with BRCS or PCS were equally dispatched between experienced practitioners and junior practitioners. The time required to remove root filling material and establish apical patency was recorded for each root canal. Samples were compared according to the sealer used and the practitioner’s experience (Mann-Whitney test).ResultsOne hundred fifteen root canals were successfully retreated. No differences in the time required to remove the filling material were observed between the 2 materials for mesiobuccal or distobuccal canals (P > .05). In contrast, the procedure was longer for palatal canals filled with BRCS compared with PCS (79.10 vs 182.45 seconds, P < .01). Experienced practitioners took significantly less time than junior practitioners (P < .05).ConclusionsBRCS can be successfully removed from root canals as quickly as a zinc oxide–eugenol sealer in both mesiobuccal and distobuccal canals but not in palatal ones. The duration of the procedure was affected by the operator’s experience independent of the filling material used or the canal type.     

The use of a radiopaque contrast medium in endodontic radiography

A series of in vitro studies were carried out to investigate the use and application of a radiopaque contrast medium in conventional periapical dental radiography for the diagnosis and evaluation of root canal systems. The water-soluble radiopaque contrast medium was introduced into the root canals of 30 first permanent maxillary and 30 first permanent mandibular molar teeth. The radiographic images of these teeth with and without radiopaque contrast medium in the root canal systems were compared and contrasted. Further comparisons were made with the same teeth rendered transparent. The results indicate that by standardizing the diagnostic criteria the inter-examiner reliability was in good agreement; it was independent of the radiographic technique used. The validity of the radiographs was enhanced by the use of the radiopaque contrast medium. The results confirm that, with the use of a radiopaque contrast medium, images of root canal systems are easier to read and interpret than plain radiographic images of root canal systems. The use of radiopaque contrast medium in endodontic radiography may be a valuable aid in the diagnosis and evaluation of root canal systems. This system would complement rather than replace plain radiography.     

Development and Validation of a Visually Explainable Deep Learning Model for Classification of C-shaped Canals of the Mandibular Second Molars in Periapical and Panoramic Dental Radiographs

IntroductionThe purpose of this study was to develop and validate a visually explainable deep learning model for the classification of C-shaped canals of the mandibular second molars in dental radiographs.MethodsThe periapical and panoramic images of 1000 mandibular second molars were collected from 372 patients. The diagnostic performance of the deep learning system using periapical and panoramic radiographs was investigated in respect to its ability to determine whether the second mandibular molar showed a C-shaped canal configuration. The assessment of the canal configuration of cone-beam computed tomographic volumes from 372 patients (740 mandibular second molars) was used as a gold standard.ResultsThe deep convolutional neural network algorithm model showed high accuracy in predicting the C-shaped canal variation among mandibular second molars in both periapical and panoramic images. The model demonstrated best results when using image patches including only the root portion of the tooth and when using both periapical and panoramic images for training (area under the curve [AUC] = 0.99). The model's diagnostic performance using only the root portion of the tooth (AUC: periapical = 0.98 and panoramic = 0.95) was similar to a specialist (AUC: periapical = 0.95 and panoramic = 0.96) and better than a novice general clinician (AUC: periapical = 0.89 and panoramic = 0.91). Both the specialist and general clinician showed better diagnostic performance when reading panoramic radiographs compared with periapical images.ConclusionsWith further optimization of the test data using a larger data set and improvements made in the model, a deep learning system may be expected to effectively diagnose C-shaped canals and aid clinicians in practice and education.     

Association between the Root Canal Configuration,Endodontic Treatment Technical Errors,and Periapical Hypodensities in Molar Teeth: A Cone-beam Computed Tomographic Study

IntroductionThis study aimed to evaluate the association between the root canal configuration (RCC), endodontic technical errors, and periapical hypodensities in molars using cone-beam computed tomographic (CBCT) images.MethodsTwo hundred twenty-one roots were assessed from 79 patients referred for CBCT examination because of symptomatology in endodontically treated molars. Two oral and maxillofacial radiologists classified the RCC of each dental root according to Vertucci's classification. Root canals were assessed for the presence of technical errors from endodontic treatment. The presence of periapical hypodensity for each dental root and the coronal sealing condition of each tooth were also recorded.ResultsFor RCC type I, the most prevalent technical error was underfilling (17.4%). For types II and VIII, nonfilled canals were found in 54% and 100% of the cases, respectively. For type III, underfilling, nonhomogeneous filling, and nonfilled canals were equally frequent (33.3%), whereas for type IV underfilling and nonfilled canals had a prevalence of 42%. In general, there was a higher prevalence of apical hypodensities among roots with technical errors. It was also observed for type I, with an increase from 41.2%–62.9% when a technical error was present.ConclusionsThe prevalence of different endodontic technical errors varies depending on the RCC for molars. A greater complexity of RCC is related to a higher occurrence of errors and a higher prevalence of periapical hypodensity.     

Influence of residual bacteria on periapical tissue healing after chemomechanical treatment and root filling of experimentally infected monkey teeth

The purpose of this study was twofold: first, to determine the influence on the healing of the periapical tissues when selected bacterial strains and combinations thereof remain after root canal treatment; and, second, the relationship to healing of the quality of the root filling. In eight monkeys, 175 root canals, previously infected with combinations of four or five bacterial strains and with radiographically verified apical periodontitis, were endodontically treated, bacteriologically controlled, and permanently obturated. After 2-2.5 yr, the periapical regions were radiographically and histologically examined. Of these teeth, 48 root canals were also examined for bacteria remaining after removal of the root fillings. When bacteria remained after the endodontic treatment, 79% of the root canals showed non-healed periapical lesions, compared with 28% where no bacteria were found. Combinations of residual bacterial species were more frequently related to non-healed lesions than were single strains. When no bacteria remained, healing occurred independently of the quality of the root filling. In contrast, when bacteria remained, there was a greater correlation with non-healing in poor-quality root fillings than in technically well-performed fillings. In root canals where bacteria were found after removal of the root filling, 97% had not healed, compared with 18% for those root canals with no bacteria detected. The present study demonstrates the importance of obtaining a bacteria-free root canal system before permanent root filling in order to achieve optimal healing conditions for the periapical tissues.     

Quality of Root Filling after Obturation with Gutta-percha and 3 Different Sealers of Minimally Instrumented Root canals of the Maxillary First Molar

IntroductionThe aim of this study was to compare the quality of root fillings completed by a modified single-cone (MSC) technique with 3 different sealers after minimal instrumentation and multisonic cleaning of root canals of maxillary first molars.MethodsRoot canals of 18 maxillary first molars were instrumented to size 15/.04 taper using rotary files. Sodium hypochlorite 5.25% was used during instrumentation; the final cleaning was performed by the GentleWave System (Sonendo Inc, Laguna Hills, CA). The specimens were allocated into 3 groups and root filled by the MSC technique using a size fitted gutta-percha master cone and GuttaFlow Bioseal (Coltene Whaledent GmBH + Co KG, Langenau, Switzerland), GuttaFlow 2 (Coltene Whaledent GmBH + Co KG), and MTA Fillapex (Angelus Industria de Produtos Odontológicos S/A, Londrina, PR, Brazil) sealers. Micro–computed tomographic scans were obtained before and after instrumentation, post-GentleWave, and after obturation. Reconstructed images were analyzed for the volumetric percentage of filling materials. Mesiobuccal roots of the selected teeth were sectioned at 0.5-mm increments starting at the apex of the root. The cross sections were further examined using a light microscope.ResultsThe 3 groups had 90%–99% of the canal space filled with the root filling material. The mean volume of the filling material was higher in the GuttaFlow Bioseal and GuttaFlow 2 groups than in the MTA Fillapex group (P < .05). There was no significant difference among the apical, middle, and coronal thirds. The cross-sectional images showed no obvious gaps or voids in the GuttaFlow groups. After instrumentation, 49 of the 189 canal thirds (25.9%) had hard tissue debris in the root canal system. After GentleWave cleaning, only 4 of 63 canals (6.3%) and 4 of the 189 canal thirds (2.1%) still had debris.ConclusionsThe MSC method with GuttaFlow 2 and GuttaFlow Bioseal sealers after multisonic cleaning of minimally instrumented molar canals resulted in high-quality root fillings. Multisonic cleaning of minimally instrumented molars seems to be effective in debris removal.