Root-end Preparation Research Articles

Outcome of Periapical Surgery in Molars: A Retrospective Analysis of 424 Teeth

IntroductionThe objective of this retrospective study was to assess the outcome of periapical surgery in a large number of molars in order to identify possible variables that might affect the outcome. MethodsThe healing outcome of patients undergoing periapical surgery of molars from October 1999 to October 2019 was retrospectively evaluated. Outcome was dichotomized into “healed” and “nonhealed” using well-established clinical and radiographic healing criteria. The potential influence of patient-, tooth-, and treatment-related parameters on the healing outcome was analyzed. ResultsA total of 424 molars in the same number of patients (45.5% male and 54.5% female) were evaluated. Three hundred seventy-two molars were classified as healed (87.7%). Three significant outcome predictors were identified: 1-year follow-up versus >1–5 years, >5–10 years, and >10 years (95.3% vs 82.2%, 76.3%, and 76.5% healed, respectively; P < .0001); root end filling material with bioceramic root repair material versus mineral trioxide aggregate (96.9% vs. 86.3% healed, respectively; P = .001); and preoperative evaluation based on cone-beam computed tomographic imaging versus 2-dimensional radiography (90.2% vs 81.4% healed, respectively; P = .02). Sex, age, tooth location, type of restoration, attachment level, presence of a post, quality of the root canal filling, technique of root end preparation, administration of antibiotics, and type of surgery had no significant impact on the healing outcome. ConclusionsThe healed rate for the concave (Retroplast) and cavity (mineral trioxide aggregate, SuperEBA [Staident International, Staines, UK], and bioceramic root repair material) root end preparation technique over all follow-up periods was 84% and 88.5%, respectively. The follow-up period, root end filling material, and preoperative evaluation based on cone-beam computed tomographic imaging had a significant influence on the healing outcome.

Effect of Heat Softening versus Ultrasonic Removal of Root-End Gutta-Percha on the Quality of Root-End Preparation for Endodontic Microsurgery.

This study is aimed at comparing the efficacy of heat softening and ultrasonic removal of root-end gutta-percha during retrograde preparation for root apical microsurgery. Recently extracted single-rooted premolars (n = 40) were prepared with standardized endodontically treated and root-end resection and then randomly divided into four groups that received root-end cavity preparation using four different instruments: a diamond-coated ultrasonic tip (AS3D; SACTEON, Paris, France), AS3D with the modified plugger of cordless heat carrier (MSE; B&L Biotech, Bala Cynwyd, PA, USA), stainless steel ultrasonic tip (Jetip-2; B&L Biotech, Bala Cynwyd, PA, USA), or Jetip-2 with MSE. The time required for root-end preparation was recorded. The root apex samples were examined by scanning electron microscopy to assess root surface microcracks and marginal integrity. The remnants of gutta-percha on the cavity walls were evaluated using a stereomicroscope. Statistical analysis was performed using Student's t-test and Wilcoxon rank-sum test (P < 0.05). Usage of MSE with Jetip-2 significantly reduced preparation time from 99.8 ± 6.8 s to 32.4 ± 1.0 s (P = 0.009), the number of microcracks from 42 to 13 (P = 0.036), and the remnants of gutta-percha from 80% to 20% (P = 0.041). Similar results were observed for AS3D with MSE. The heat softening of MSE was effective in cleaning gutta-percha, thus greatly improving the efficiency of the root-end preparation, thereby producing a root-end cavity with fewer microcracks and better marginal integrity.

Marginal gaps and internal voids after root-end filling using three calcium silicate-based materials: A Micro-CT analysis.

This study evaluated the 3D quality of root-end filling, assessing the presence (volume and percentage) of marginal gaps and internal voids formed after retro-filling with three calcium silicate-based materials: MTA Angelus (Angelus Soluçoes Odontologicas, Londrina, PR, Brazil), Biodentine (Septodont Ltd., Saint Maur-des-Faussés, France) and Neo MTA Plus (Avalon Biomed Inc., Bradenton, Florida, US). Thirty human, extracted, single rooted teeth were used. Orthograde root canal treatment, root resection (3mm shorter than the apex) and retrograde cavity preparation with ultrasonic tips were performed. Teeth were divided into 3 groups (n =10 each) following a stratified randomization according to the initial volume of the root-end cavity. After retrofilling, samples were stored for 7 days. Then, two rounds of micro-CT scans were performed: soon after root-end preparation (with the cavity still empty) and 7 days after root-end filling. Marginal gaps, internal voids volume (mm3 and %), as well as, the overall defects (sum of gaps and voids) were evaluated. Statistics compared the three groups in relation to those defects. There was not statistical difference between groups regarding the marginal gaps (P≥ 0.05), the internal voids (P≥ 0.05), and the overall defects (P≥ 0.05). Median (mm3) and % of overall air-entrapment defects (gaps and/or voids) was: 0.004mm3 and 1.749% for MTA Angelus, 0.018mm3 and 6.660% for Biodentine, and 0.012mm3 and 4.079% for Neo MTA Plus. All materials had gaps and/or voids. No differences were found between MTA Angelus, Biodentine and Neo MTA Plus.

Effect of Irrigating Agitation after Root End Preparation on the Wall Cleaning and Bond Strength of Calcium Silicate Material in Retrograde Obturation.

Objective This study aimed to evaluate the cleaning efficacy of irrigant activation with a new ultrasonic tip in root-end preparations and to determine its influence on the bond strength of calcium silicate-based material. Materials and Methods Maxillary canines were prepared and filled, and their root ends resected. Root-end cavities were ultrasonically prepared and randomly distributed into four groups according to the final irrigation protocols: G1 (ultrasonic irrigation [UI] + saline solution [SS]), G2 (syringe irrigation [SI] + SS), G3 (UI + ethylenediaminetetraacetic acid [EDTA]), and G4 (SI + EDTA). Cleaning efficacy analysis employed 72 specimens ( n = 18) split longitudinally for imaging of the same areas by scanning electron microscopy (SEM). The percentage of dentinal tubules opened before and after irrigation was used as evaluation parameter. Push-out testing employed 40 specimens ( n = 10) sectioned apical region perpendicularly, which slice was placed on a testing machine for the bond strength measurement and failure mode was assessed by SEM. The data were statistically analyzed (α ≤ 0.05). Results G3 (UI + EDTA) removed the smear layer more effectively, showed the best tubule opening ( p < 0.05), and presented the highest mean bond strength values ( p < 0.05). Failure modes were predominantly adhesive, except for the G3 (UI + EDTA) group, in which they were mainly mixed (80%). Conclusion The results of this study suggest that EDTA 17% agitation promoted better cleaning and smear layer removal, improving the push-out bond strength of calcium silicate material in retrograde obturation.

Comparative evaluation of marginal adaptation of two root end filling materials in root end preparation done with diamond points and ultrasonics - An in vitro SEM study

The aim of the present study was to evaluate the marginal adaptation of two bioceramic root end filling materials in root end preparation done with diamond points and ultrasonics under scanning electron microscope.: 56 single rooted extracted human teeth were collected and decoronated to create a standardized length of 14mm and were then endodontically treated. The treated tooth were resected 3mm from the apex at 90 degree angle to long axis of the tooth.The samples were then randomly divided into two groups, group I and group II of 28 samples each. Group I and group II were further divided into subgroup A and subgroup B of 14 samples each. Root end preparations in subgroup A of both the groups were done using ultrasonic tips and in subgroup B of both the groups root end preparations were done using diamond points and In Group I all the root end preparation were filled with MTA(Angelus) and in group II with Biodentine.The apical portions of the roots were then sectioned to obtain 1mm thick transversal sections, scanning electron microscopy was used to determine the adaptations of the root end filling materials with the dentin. Two way Anova and Tukeys Multiple Posthoc test was used for statistical data analysis.: Lowest mean marginal gap of 0.46 micron meter seen with Group II (a) and highest marginal gap of 0.83micron meter seen with Group I (b), which were statistically significant (P&amp;#60;0.05).: Biodentine group, root end preparation done using ultrasonics showed best marginal adaptation than all the other tested groups.

Evaluation of microcrack formation after root-end preparation with two different types of ultrasonic retrotips and conventional bur: A stereomicroscopic study

Introduction: The aim of this in vitro study is to evaluate and compare the root-end cavities for the presence of microcracks after cavity preparation using two different ultrasonic (US) retrotips and conventional bur.Materials and Method: Thirty single-rooted teeth were instrumented and obturated. Three millimeters of apices were resected. Retrograde Class I cavities 3 mm deep were prepared on resected surfaces of ten teeth with diamond-coated US retrotip (Group 1), ten teeth with zirconium-nitride-coated US retrotip (Group 2), and ten teeth with conventional bur (Group 3). The root-end surfaces were examined under a stereomicroscope and the resected root surfaces were evaluated for the presence of microcracks on microphotographs.Results: Statistically significant difference was detected between diamond-coated and zirconium-nitride-coated US retrotips and also significant difference was detected when the same were compared with conventional bur for the presence of microcracks.Conclusion: Within the limitations of the study, it can be concluded that both zirconium-nitride- and diamond-coated retrotips produce more dentinal crack formation compared to conventional bur, but none of them produce a complete crack. Moreover, the diamond-coated retrotips produce less debris formation and minimal dentinal crack compared to zirconium-nitride-coated retrotips.

Role of Microscope in Endodontics

Microscope is used in medical field to run over the limitations of human vision. Over the years many magnification devices are invented to achieve the goal. Quote given by Prof Syngcuk Kim that states “You can only treat what you can see”. If the right tools are available many things can be visualized. They are endoscopes, intraoral camera, magnifying glass, surgical loupes, surgical microscope. Surgical loupes and Dental Operating Microscope are most convenient and practical to use in endodontics. By increasing the image size, fine details can be visualized. Hence to increase the image size, magnification is necessary. The invention of microscopes in modern endodontics helps in visually guided and sensory aided endodontic procedure. Magnification helps visualise finer details of the area to be treated. Dental microscope is used for diagnostic and clinical procedures (non-surgical ) as well as endodontic surgical procedures. The microscope as a diagnostic tool may be used in caries detection, fracture line and craze evaluation, crown margins or restorations that are deficient, in caries elimination, access preparation, calcifications removal. It is also helpful in orifice detection and treating internal resorptions. All procedure are performed under various magnification grades. They are flap surgery, cutting of bone, root apex identification, apicoectomy, removal of inflamed tissue, observe resected end of root, root end preparation, retrograde filling, and suturing, surgical correction of unsuccessful RCT. Also, Cervical resorption and External resorption and perforation repairs can be done using Microscope. The invention of microscopes in modern endodontics helps in visually guided and sensory aided endodontic procedure. Furthermore the role of microscopes in endodontics is reviewed.

Occurrence of Vertical Root Fractures after Apical Surgery: A Retrospective Analysis

IntroductionVertical root fractures (VRFs) are among the most frequent causes of tooth loss, mainly of endodontically treated teeth. However, very few data is available about the occurrence of VRFs following apical surgery. MethodsPatient charts from 864 patients with 1058 teeth treated with apical surgery (September 1999 to December 2018) were retrospectively evaluated, if a VRF had occurred after surgery. The following, possibly influencing factors were analyzed: sex and age, type of treated tooth, primary versus resurgery, technique of root-end preparation, and timepoint of VRF diagnosis. Endpoints were either tooth extraction or the last follow-up. ResultsThe study cohort (55% women, 45% men) had a mean age of 52.00 ± 13.97 years (range 9–93 years). The overall rate of VRFs after apical surgery was 4% (42 of 1058 teeth). Among these 42 teeth, 33.3% were mandibular first molars and 26.2% were maxillary second premolars. The most frequently affected root was the mesial root of mandibular first molars (28.6%). With regard to the study parameters, significant differences of VRF rates were observed only for the type of tooth treated. ConclusionsA low VRF rate of 4% was observed in this study. VRFs commonly occurred in maxillary premolars and mandibular molars, with the mesial root of mandibular first molars affected most frequently. This is in line with previous reports about VRFs in endodontically treated teeth without additional apical surgery.

Evaluation of Root-End Preparation with Two Different Endodontic Microsurgery Ultrasonic Tips.

The aim of this study is to compare root-end preparation performed with two different ultrasonic tips—CVDentus and NSK—and respective time requirements. After root-end resection, 32 teeth were randomly divided in two groups, according to the ultrasonic tip used for root-end preparation. Preparation time was recorded. Photomicrographs were taken to assess the following parameters: root surface microcracking, marginal integrity and presence of debris. One ultrasonic tip from each group was analyzed through scanning electron microscopy before and after root-end preparation. The significance level was set at α = 0.05. Incidence of microcracks in both groups was 12.5%. Solely intracanal microcracking was found, consistently positioned within the widest side of the remaining dentine. No statistically significant differences were verified between both experimental groups regarding marginal integrity (p = 0.102) and preparation time (p = 0.780), whereas statistical differences (p = 0.003) were found concerning the presence of debris (the minimum registered score was mostly verified in CVDentus group). NSK tips showed major morphological changes, with extensive surface wear and noticeable loss of particles, which was not verified on CVDentus tips. Our findings suggest significant differences regarding root-end preparation walls quality, with CVDentus tips showing better results. Concerning microcracking, as well as preparation time and marginal integrity, both ultrasonic tips showed similar results. Qualitative analysis exposed NSK tips major morphological changes and wear after use, which was not verified on CVDentus tips.

The Effect of Root End Cavity Preparation Using Er,Cr:YSGG Laser, Ultrasonic Retrotip, and Bur on the Apical Microleakage of Retrograde Cavity Filled with MTA Plus.

ABSTRACTAim:The sealing ability of the retrograde material is greatly affected by the technique used for root end preparation. Advances in retrograde preparation techniques such as lasers has shown to provide an efficient outcome. The study was to evaluate and compare the effect of various techniques of retrograde cavity preparation on apical microleakage.Materials and Methods:Forty-five single rooted teeth were decoronated. Biomechanical preparation was carried out up to size F2 ProTaper system and obturated. Glass–ionomer cement was used as an access restorative material. The apical root resection was done at 3 mm from the apex at angulation of 90° to the long axis of the root. The allocation of the samples was done into three groups of 15 each. Group A: Retrograde cavities prepared using conventional round bur; Group B: Retrograde cavities prepared using ultrasonic retro preparation diamond tip; and Group C: Retrograde cavities prepared using “Erbium, chromium: yttrium, scandium, gallium, garnet” (Er,Cr:YSGG). The retrograde cavities hence prepared were filled with MTA Plus. Nail varnish was used to coat the samples except at the apical end. Samples were immersed in methylene blue for 24h. Stereomicroscope was used for examination of the sectioned teeth. The data were analyzed using one-way analysis of variance (ANOVA) and post hoc Tukey test.Results:Results showed very highly significant difference between laser and bur (P value = 0.001).Conclusion:Retrograde preparation with Er,Cr:YSGG showed significantly less microleakage when compared to the use of ultrasonic retrotip and burs.

Evaluation of Crack Formation and Propagation with Ultrasonic Root-End Preparation and Obturation Using a Digital Microscope and Optical Coherence Tomography.

Objective This study is aimed at determining (1) the effect of root-end resection, ultrasonic root-end preparation, and root-end filling on the incidence of crack formation and propagation by using a digital microscope (DM) and optical coherence tomography (OCT) and (2) the performance of OCT on the detection of cracks by comparing with microcomputed tomography (micro-CT) as a reference standard. Methodology Thirty extracted lower incisors were endodontically treated and subjected to root-end resection and ultrasonic root-end cavity preparation. Then, the teeth were divided into three groups (n = 10, each), and the root-end cavity was either left unfilled or filled with mineral trioxide aggregate (MTA) or super-EBA. The resected surface was observed with OCT and DM after the root-end resection, ultrasonic root-end preparation, and root-end filling, and the frequency of incomplete and complete cracks were recorded. The observation was repeated after two weeks, one month, and two months, and micro-CT scans after two months were taken as the gold standard. Results The DM results show dentinal crack formation in 47% of the samples following root-end resection and in 87% following ultrasonic preparation. After the ultrasonic preparation, no existing crack propagated to a complete crack, but new cracks were formed. MTA and super-EBA had no effect on crack formation. The Spearman correlation coefficient between OCT and DM was 0.186 (very weak correlation; p = 0.015). Sensitivity and specificity in comparison to micro-CT were 0.50 and 0.55 in OCT and 1.00 and 0.35 in DM, respectively. McNemar's test showed a significant difference between OCT and DM (p < 0.05). Conclusion Apical resection and ultrasonic preparation could form dentinal cracks. OCT and DM showed different detection frequencies of cracks with very weak correlation. DM showed superior sensitivity compared with OCT.

Intentional Replantation with a 2-segment Restoration Method to Treat Severe Palatogingival Grooves in the Maxillary Lateral Incisor: A Report of 3 Cases

The palatogingival groove is a developmental anomaly that typically starts near the cingulum of the maxillary incisors and extends along the roots at varying lengths and depths. Severe grooves that extend to the root apex often lead to complex combined periodontal-endodontic lesions. There are various therapeutic options available for these cases; however, the prognosis is unfavorable. Here, we report the successful surgical treatment of 3 cases of maxillary lateral incisors with severe palatogingival grooves using intentional replantation with a 2-segment restoration method. The teeth were gently extracted, resulting in minimal damage to the periodontal ligament. Under a dental operating microscope, 3 mm of the root end was resected. The palatogingival groove was removed, and root-end preparation was performed with a #700 fissure bur. The groove cavity was connected with root-end cavity to form a class II cavity. The cavity was then filled using a 2-segment restoration method (ie, dividing the cavity into 2 parts by the cementoenamel junction, the coronal portion was filled with a flowable composite while the radicular portion, including the root-end cavity, was filled with bioceramics). The tooth was then replanted into its alveolar bone and splinted with a flexible splint for 7 days. The sinus tract was closed at the 1-week postoperative visit. During subsequent recalls, the teeth showed almost complete periapical healing. In summary, intentional replantation with a 2-segment restoration method is a viable treatment modality for single-rooted teeth with a severe palatogingival groove that extends to the root apex.

Marginal Adaptation of a new Formulation of MTA Material used as Root-End Filling: A Scanning Electron Microscopy (SEM) Study

Introduction Achieving a hermetic apical seal is mandatory to prevent ingress of any microorganisms or periapical fluids into the root canal system. Therefore it is essential to develop new materials having favorable physical, chemical and biological properties. Aim the purpose of this study was to use scanning electron microscopy to compare the marginal adaptation of new formulation of MTA (Harvard MTA), MTA flow and glass ionomer as root end filling materials using ultrasonic root-end preparation. Methodology Thirty-nine extracted single rooted human teeth were prepared using Protaper Next file system (Dentsply/Sirona) and filled with gutta-percha and MTA fillapex sealer (MTA Fillapex; Angelus, Londrina, Brazil) and obturated using cold lateral compaction technique. The apical 3 mm of the roots were sectioned perpendicular to the long axis of the roots. A 3-mm depth root-end cavity was prepared with ultrasonic tips powered by an Enac ultrasonic device. The teeth were randomly allocated into three groups of 13 teeth each according to filling materials tested. Group I the samples were filled with Harvard MTA (Universal, Handmix, Germany, Harvard), Group II filled with MTA Flow (Ultradent Products Inc., South Jordan,UT, USA), group III filled with glass ionomer (Fuji II, GC gold label 2, GC International, Japan). Using SEM the distance between the tested materials and the surrounding dentin was measured at different points.Results According to the results of Kruskal-Wallis, there was significant difference between the three experimental groups at P value 0.01. The Man Whitney test was used for two-by-two comparison of the groups which revealed no statistical significant difference between MTA flow and MTA Harvard group however; there was statistically significant difference in Glass Ionomer group. Conclusion SEM results showed the presence of gaps in the root-end filling materials in all groups. MTA flow has the best marginal adaptation followed by MTA Harvard while the Glass Ionomer showed the least marginal adaptation.

Effect of ultrasonic root-end cavity preparation on dentinal microcrack formation: A micro-computed tomography study.

Background:Root-end preparation during surgical endodontics may produce dentinal microcrack formation and/or propagation, leading to vertical root fractures.Aim:This study aimed to evaluate and compare the microcrack formation and propagation during ultrasonic root-end cavity preparation, with diamond- and zirconium nitride-coated tips using micro-computed tomography (CT).Methodology:Twenty-eight extracted, mature, free-of-defect, mandibular premolars were decoronated and micro-CT scanned for the presence of preexisting microcracks. Samples were prepared till F4, were obturated, and were re-scanned to determine an increase in the number of microcracks. After 3 mm of root-end resection, the samples were randomly divided for ultrasonic root-end preparation into Group 1 (n = 12): preparation was done with ProUltra Surg tip, Group 2 (n = 12): preparation was done with KiS tip, and Group 3 (n = 4): no preparation was done. The samples were rescanned, and data collected were analyzed using ANOVA and Student's t-test. The level of significance was set at 5%.Results:Preexisting microcracks were observed in few samples. The mean percentage number increase of microcracks after root-end preparation in ProUltra Surg group was 1.25 and in KiS group, it was 0.5. The difference in mean percentage increase for the number of microcracks after root-end cavity preparation using ProUltra Surg tip and KiS tip was 0.75. However, this difference was not statistically significant (P = 0.34).Conclusion:Both diamond- and zirconium nitride-coated ultrasonic tips resulted in more number of dentinal crack formation and propagation when preexisting cracks were present.

Comparative evaluation of the sealing ability of filling materials on root end cavities treated with smear layer removing agents: A confocal laser scanning microscopic study.

Aim:This study aims to evaluate and compare the sealing ability of Biodentine™ and mineral trioxide aggregate (MTA) plus® on root end cavities treated with 17% ethylene diamine tetraacetic acid (EDTA), 0.2% Chitosan and 1% Phytic acid using Confocal Laser Scanning Microscope (CLSM)-An in vitro study.Materials and Methods:Sixty extracted single rooted teeth were instrumented and obturated with gutta-percha. The apical 3 mm of each tooth was resected and 3 mm root-end preparation was made using ultrasonic tip. 17% EDTA (n = 20), 0.2% Chitosan (n = 20) and 1% Phytic acid (n = 20) was used as a smear layer removing agent and each above group was further subdivided and restored with a root end filling material, Biodentine (n = 10) and MTA Plus (n = 10). The samples were coated with varnish except at the root end and after drying, they were immersed in Rhodamine B dye for 24 h. The teeth were then rinsed, sectioned longitudinally, and observed under CLSM.Results:In the present study, MTA Plus® treated with 1% Phytic acid showed the least microleakage followed by Biodentine™ treated with 1% Phytic acid which was statistically not significant. MTA Plus® treated with 17% EDTA showed the highest microleakage when compared to other tested groups. There was a significant difference in microleakage between MTA Plus® and Biodentine™ when treated with 17% EDTA and 0.2% Chitosan. However, more microleakage was seen with Biodentine™ group than MTA plus® group.Conclusion:Root end cavities restored with MTA plus and treated with Phyitc acid showed superior sealing ability. Furthermore, smear layer removing agents will aid in better adaptability of root end filling material.

The Simultaneous Effect of Apical Resection Angle and Depth of Retrograde Cavity on Apical Microleakage via Fluid Filtration Method.

The goal of apical surgery is to eliminate the root apex, apical lesions and promote tissue repair. In apical surgery, the root is resected at an angle of 45, 60 or 90 degree. In many cases, it is not possible to resect the root at 90-degree bevel and prepare a root-end cavity with 4-mm depth. The aim of this study was to evaluate the simultaneous effect of apical resection angle and depth of the retrograde filling with mineral trioxide aggregate (MTA) on apical microleakage. Root ends were resected at 45 degree, 60 degree and 90 degree bevels in 110 extracted human single root permanent teeth. For each apical surgery, root-end cavities were filled with MTA to depths of 2 mm, 3 mm and 4 mm. Root end-filled teeth were mounted in fluid filtration device. The evaluation was conducted after 24-h, 1 week, 1 month, 2 months and 3 months. Each group included 10 samples. Also 20 roots were used as positive and negative control samples, in the negatives the entire root surface was coated with 2 layers of nail varnish and positives were unfilled root-end preparation. Statistical analysis consisted of the Kruskal-Wallis test and Pairwise comparison. There were no significant differences in apical microleakage after 24 h and 1 week in the experimental groups. In the 3rd month, samples with 90° bevel and 4-mm-thick MTA showed significant statistical differences with all samples with 45° and 60° bevels and depths of 2- and 3-mm-thick MTA (P<0.05). This in vitro study showed that when the resection angle is 90°, retrograde depth does not affect microleakage, but resection angles other than 90°, require 4 mm-retrograde depth to be sealed.

Targeted Endodontic Microsurgery: A Novel Approach to Anatomically Challenging Scenarios Using 3-dimensional–printed Guides and Trephine Burs—A Report of 3 Cases

Endodontic microsurgery (EMS) techniques have increased success rates over traditional approaches. Despite surgical advances, anatomically challenging scenarios can preclude EMS in certain cases. The aim of this article was to introduce targeted EMS, which uses 3-dimensional–printed surgical guides (3DSGs) and trephine burs to achieve single-step osteotomy, root-end resection, and biopsy in complex cases. In each of 3 cases, a 3DSG with a trephine port was printed using computer-aided design/computer-aided manufacturing implant planning software. The osteotomy site, angulation, and depth of preparation were defined preoperatively to avoid sensitive anatomic structures. The 3DSG was inserted at the target site to achieve precise osteotomy and root-end resection during surgery. A hollow trephine rotated within the 3DSG port produced single-step osteotomy, root-end resection, and biopsy. Root-end preparation and fill were accomplished, and tissues were sutured in place. Targeted EMS potentiated successful surgical treatment in 3 anatomically challenging scenarios: (1) a palatal approach to the palatal root of a maxillary second molar, (2) a facial approach to a fused distofacial-palatal root of a maxillary first molar, and (3) a mandibular second premolar in close proximity to the mental foramen. Trephine burs guided by 3DSGs produce efficient targeted osteotomies with a predictable site, angulation, and depth of preparation. Apical surgery in challenging anatomic cases such as the palatal root of the maxillary second molar, fused molar roots, and root ends in approximation to the mental nerve are possible with targeted EMS.

Evaluation of Quality and Preparation Time of Retrograde Cavities in Root Canals Filled with GuttaCore and Cold Lateral Condensation Technique

IntroductionThe aim of this study was to measure the time consumed preparing retrograde cavities in root canals of maxillary molars filled using the GuttaCore (Dentsply Tulsa Dental Specialties, Tulsa, OK) technique and the cold lateral condensation technique (CLC) and to examine the quality of the root-end cavity preparation by ultrasonic tips using micro–computed tomographic (micro-CT) scanning. MethodsA total of 24 maxillary molars were included; distobuccal and palatal canals were instrumented to size #40 and size #50, respectively. Teeth were randomly distributed into 2 experimental groups; half of the samples were filled with CLC, and half were filled with the GuttaCore technique. After 2 months, the apical 3 mm of each root apex was resected. A retrograde cavity was then prepared 3 mm deep into the root-end–filled canals using ultrasonic tips. The quality of the preparation was first confirmed by a surgical stereomicroscope, and the time required for the root-end preparation was recorded. After root-end cavity preparation, all samples were scanned by micro-CT scanning. ResultsThere was no significant difference between the palatal and distobuccal canals in the time required to prepare a retrograde cavity. Less time was required in the GuttaCore group to remove all root filling material and finish the cavity preparation than in the CLC group (P < .05), especially in the palatal canals. Micro-CT results confirmed that all material was removed from the root-end cavities and the absence of microcracks. ConclusionsGuttaCore was removed in less time from root-end cavities than root filling performed with the CLC technique. No damage to the surrounding dentin was detected by micro-CT scanning in the 2 groups.

Comparison of Gap Volume after Retrofilling Using 4 Different Filling Materials: Evaluation by Micro–computed Tomography

IntroductionThe purpose of this study was to evaluate the gap volume between dentin and root-end filling materials. MethodsFour root-end filling materials were compared in the present study: ProRoot MTA (PRM; Dentsply Tulsa Dental, Tulsa, OK), MTA Angelus (MAG; Angelus, Londrina, Brazil), EndoCem MTA (ECM; Maruchi, Wonju, Korea), and RetroMTA (RTM; BioMTA, Seoul, Korea). Forty-eight single-rooted, extracted human teeth were instrumented with nickel-titanium instruments and oburated with gutta-percha. The apical 3 mm of the root tip was resected, and root-end preparation was performed with a diamond bur. The root-end cavity was filled with the experimental filling materials for the 4 designated groups (n = 10). Then, the samples were scanned with micro–computed tomographic (micro-CT) imaging. Three-dimensional images of the samples were reconstructed, and the volume of the gap between the tooth surface (dentinal wall) and the root-end filling materials was measured. The percentage volume of the gap between the tooth structure and the root-end filling material (VG%) was calculated. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests at a significance level of 95%. ResultsThe median VG% values for the PRM, MAG, ECM, and RTM groups were 0.00472, 0.00134, 0.00014, and 0.00071, respectively. The ProRoot MTA group showed the greatest gap volume percentage among the experimental groups with a significant statistical difference (P < .05). ConclusionsFrom the micro-CT analysis, ProRoot MTA had a greater gap volume percentage than other root-end filling materials.

The alignment of ultrasonic root-end cavity preparations using an in situ cadaver model

Aim: This study aims to compare the alignment of root-end cavities prepared with ultrasonic tips with the root canal outline in teeth with and without root canal fillings using an in situ cadaver model. Materials and Methods: Twenty-eight bilaterally matched pairs of human teeth from five cadavers were equally divided into two groups: teeth with root canal fillings (RCF) and teeth without root canal fillings (NRCF). The resected root surface was stained with methylene blue and examined under magnifying loops; then, the root-end cavities were prepared in both groups using ultrasonic tips and filled with amalgam. The teeth were carefully extracted, mounted in resin blocks, radiographed from two angles, and then sectioned at 3 mm from the root end. The alignment of root-end cavities in both groups was compared using defined criteria. Results: The RCF group had a significantly higher incidence of centered root-end preparations than NRCF group on the buccolingual (79% vs. 64%) and mesiodistal (64% vs. 24%) directions. However, both groups showed high incidence of deviated cavities at the horizontal cross-section and the difference between them was not significant. Conclusions: The presence of root canal filling improved the alignment of root-end cavities prepared with ultrasonic tips.