Nanoleakage of apical sealing using a calcium silicate-based sealer according to canal drying methods.

Objectives: This study investigated the nanoleakage of root canal obturations using calcium silicate-based sealer according to different drying methods. Materials and Methods: Fifty-two extracted mandibular premolars with a single root canal and straight root were selected for this study. After canal preparation with a nickel-titanium rotary file system, the specimens were randomly divided into 4 groups according to canal drying methods (1: complete drying, 2: blot drying/distilled water, 3: blot drying/NaOCl, 4: aspiration only). The root canals were obturated using a single-cone filling technique with a calcium silicate-based sealer. Nanoleakage was evaluated using a nanoflow device after 24 hours, 1 week, and 1 month. Data were collected twice per second at the nanoscale and measured in nanoliters per second. Data were statistically analyzed using the Kruskal-Wallis and Mann-Whitney U-tests (p < 0.05). Results: The mean flow rate measured after 24 hours showed the highest value among the time periods in all groups. However, the difference in the flow rate between 1 week and 1 month was not significant. The mean flow rate of the complete drying group was the highest at all time points. After 1 month, the mean flow rate in the blot drying group and the aspiration group was not significantly different. Conclusions: Within the limitations of this study, the canal drying method had a significant effect on leakage and sealing ability in root canal obturations using a calcium silicate-based sealer. Thus, a proper drying procedure is critical in endodontic treatment.

A Study on Nanoleakage of Apical Retrograde Filling of Premixed Calcium Silicate-Based Cement Using a Lid Technique.

This study aimed to compare the nanoleakage of retrograde fillings with premixed calcium silicate-based putty and mineral trioxide aggregate (MTA), using two different techniques (traditional and Lid). Sixty-four extracted human teeth were decoronated, then root canals and ends were instrumented for retrograde filling and divided into four groups according to the retrograde filling technique: the traditional and the Lid technique. Each group (n = 15) was filled with Ceraseal + Well-Root putty, Well-Root putty, Ceraseal + ProRoot MTA, and ProRoot MTA. The nanoleakage was evaluated using the Nanoflow device (IB Systems) on days 1, 3, 7, 15 and 30. Data were collected twice per second at the nanoscale (nL/s) and calculated after archiving the stabilization of fluid flow. The Kruskal-Wallis and Mann-Whitney U-tests were used for statistical analysis. All groups showed enhanced sealing ability over time. Regardless of filling materials, the Well-Root putty, Ceraseal+Well-Root putty, and Ceraseal+ProRoot MTA groups indicated less nanoleakage than the ProRoot MTA group in the first week of evaluation (p < 0.05). Although all groups did not show significant differences after 2 weeks, the Ceraseal+ProRoot MTA group leaked less than ProRoot MTA on Days 3 and 7 (p < 0.05). The scanning electron microscopic examined good adaptation to the cavity wall, which was similar to nanoleakage results. Premixed calcium silicate-based putty retrograde filling material alone and using the "lid technique" were shown to be faster and less prone to nanoleakage when compared to MTA.

Patient discomfort levels during instrumentation procedure using nickel-titanium files with different kinetic movements.

This study evaluated the perceived vibration, noise and discomfort levels associated with two nickel-titanium file systems with different kinetics; reciprocating motion (REC) using WaveOne Gold and continuous rotation motion (CON) using ProTaper NEXT. Forty roots with two canals from maxillary premolar and molar of 40 patients were included. Root canals were instrumented using each system for each canal. Patients were surveyed about the vibration, noise and discomfort experienced using visual analogue scale, and their preference. The responses were statistically analysed using Wilcoxon Signed-Rank test, Mann-Whitney U test and Spearman's rank correlation test at the 95% of significance level. The vibration, noise and discomfort experienced were significantly greater in REC than CON (P < 0.05). In REC, male subjects reported significantly higher vibration than female (P < 0.05). Majority respondents (72.5%) preferred the CON method. The perceived vibration, noise and discomfort were less apparent from the CON than the REC.

A cone-beam computed tomography study of the prevalence and location of the second mesiobuccal root canal in maxillary molars.

OBJECTIVES: This study aimed to investigate the incidence and location of the second mesiobuccal root (MB2) canal in maxillary molars with the aid of various measuring points and lines using cone-beam computed tomography (CT). MATERIALS AND METHODS: A total of 205 images of patients who underwent cone-beam CT examinations between 2011 and 2015 as part of their dental diagnosis and treatment were included. There were 76 images of the maxillary first molar and 135 images of the maxillary second molar. Canal orifices were detected at -1 mm from the top of the pulpal floor on cone-beam CT images. Image assessment was performed by 2 observers in reformatted image planes using software. Assessments included measurement of the distance between the MB1 and MB2 canals, and the angles between the lines connecting the MB1-MB2 and distobuccal (DB)-palatal (P) canals. The data were analyzed using the student's t-test. RESULTS: The prevalence of the MB2 canal was 86.8% in the first molar and 28.9% in the second molar. The angle between the lines connecting the MB1-MB2 and DB-P canals was 2.3° ± 5.7° in the first molar and -3.95° ± 7.73° in the second molar. The distance between the MB1 and MB2 canals was 2.1 ± 0.44 mm in the first molar and 1.98 ± 0.42 mm in the second molar. CONCLUSIONS: The angles between the lines connecting the MB1-MB2 and DB-P canals was almost parallel. These findings may aid in the prediction of the location of the MB2 canal orifice.

Comparison of vibration characteristics of file systems for root canal shaping according to file length.

OBJECTIVES: No studies have yet assessed vibration characteristics according to endodontic file length. Accordingly, the objective of the present study was to examine the vibration characteristics according to nickel-titanium file length and to compare these characteristics between different file systems. MATERIALS AND METHODS: A total of 45 root canal models were divided into 3 experimental groups (n = 15 each) based on the file system used (ProTaper Gold [PTG], ProTaper Next, or WaveOne Gold [WOG]). Each experimental group was further divided into 3 subgroups according to file length (21, 25, or 31 mm). An electric motor (X-SMART PLUS) was used in the experiment. For each file system, vibrations generated when using a size 25 file were measured and used to calculate the average vibration acceleration. The differences in vibrations were analyzed using 1-way analysis of variance and the Scheffé post hoc test with a confidence interval of 95%. RESULTS: In the PTG file system, significantly lower vibration acceleration was observed when using a 21-mm file than when using a 31-mm file. In the WOG file system, significantly stronger vibration acceleration was observed when using a 31-mm file than when using 21- or 25-mm files. Regardless of the file length, the WOG group exhibited significantly stronger vibration acceleration than the other 2 experimental groups. CONCLUSIONS: In clinical practice, choosing a file with the shortest length possible could help reduce vibrations. Additionally, consideration should be given to vibrations that could be generated when using WOG files with reciprocating motion.

Fiber-reinforced composite resin bridges: an alternative method to treat root-fractured teeth.

The replacement of missing teeth, especially in the anterior region, is an essential part of dental practice. Fiber-reinforced composite resin bridges are a conservative alternative to conventional fixed dental prostheses or implants. It is a minimally invasive, reversible technique that can be completed in a single visit. The two cases presented herein exemplify the treatment of root-fractured anterior teeth with a natural pontic immediately after extraction.

Plugger temperature of cordless heat carriers according to the time elapsed.

OBJECTIVE: The purpose of this study was to measure the temperature of the plugger tip of 3 cordless heat carriers set at 200°C. MATERIALS AND METHODS: Pluggers of the same taper (0.06, 0.08, 0.10) and similar tip sizes (sizes of 50 and 55) from 3 cordless heat carriers, namely SuperEndo-α2 (B & L Biotech), Friendo (DXM), and Dia-Pen (Diadent), were used and an electric heat carrier, System B (SybronEndo), was used as the control. The plugger tips were covered with customized copper sleeves, heated for 10 seconds, and the temperature was recorded with a computerized measurement system attached to a K-type thermometer at room temperature (n = 10). The data were analyzed with 2-way analysis of variance at a 5% level of significance. RESULTS: The peak temperature of the plugger tips was significantly affected by the plugger taper and by the heat carrier brand (p < 0.05). The peak temperature of the plugger tips was between 177°C and 325°C. The temperature peaked at 207°C-231°C for the 0.06 taper pluggers, 195°C-313°C for the 0.08 taper pluggers, and 177°C-325°C for the 0.10 taper pluggers. Only 5 of the 12 plugger tips showed a temperature of 200°C ± 10°C. The time required to reach the highest temperature or 200°C ± 10°C was at least 4 seconds. CONCLUSION: When using cordless heat carriers, clinicians should pay attention to the temperature setting and to the activation time needed to reach the intended temperature of the pluggers.

Differential diagnosis of periapical cyst using collagen birefringence pattern of the cyst wall.

OBJECTIVES: Periapical lesions, including periapical cyst (PC), periapical granuloma (PG), and periapical abscess (PA), are frequently affected by chemical/physical damage during root canal treatment or severe bacterial infection, and thus, the differential diagnosis of periapical lesions may be difficult due to the presence of severe inflammatory reaction. The aim of this study was to make differential diagnosis among PC, PG, and PA under polarizing microscope. MATERIALS AND METHODS: The collagen birefringence patterns of 319 cases of PC (n = 122), PG (n = 158), and PA (n = 39) obtained using a polarizing microscope were compared. In addition, 6 cases of periodontal fibroma (PF) were used as positive controls. RESULTS: Collagen birefringence was condensed with a thick, linear band-like pattern in PC, but was short and irregularly scattered in PG, and scarce or absent in PA. PF showed intense collagen birefringence with a short, palisading pattern but no continuous band-like pattern. The linear band-like birefringence in PC was ascribed to pre-existing expansile tensile stress of the cyst wall. CONCLUSIONS: In this study all PCs (n = 122) were distinguishable from PGs and PAs by their characteristic birefringence, despite the absence of lining epithelium (n = 20). Therefore, the authors suggest that the presence of linear band-like collagen birefringence of the cyst wall aids the diagnostic differentiation of PC from PG and PA.

Vibrations Generated by Several Nickel-titanium Endodontic File Systems during Canal Shaping in an Ex Vivo Model.

INTRODUCTION: This study aimed to compare the vibration generated by several nickel-titanium (NiTi) file systems and transmitted to teeth under 2 different motions (continuous rotation motion and reciprocating motion). METHODS: Sixty J-shaped resin blocks (Endo Training Bloc-J; Dentsply Maillefer, Ballaigues, Switzerland) were trimmed to a root-shaped form and divided into 2 groups according to the types of electric motors: WaveOne motor (WOM, Dentsply Maillefer) and X-Smart Plus motor (XSM, Dentsply Maillefer). Each group was further subdivided into 3 subgroups (n = 10 each) according to the designated file systems: ProTaper Next (PTN, Dentsply Maillefer), ProTaper Universal (PTU, Dentsply Maillefer), and WaveOne (WOP, Dentsply Maillefer) systems. Vibration was measured during the pecking motion using an accelerometer attached to a predetermined consistent position. The average vibration values were subjected to 2-way analysis of variance as well as the t test and Duncan test for post hoc comparison at the 95% confidence interval. RESULTS: Both motor types and instrument types produced significantly different ranges of average vibrations. Regardless of the instrument types, the WOM group generated greater vibration than the XSM group (P < .05). Although PTN and PTU did not show significant differences, the WOP group showed significantly greater vibration than the other groups regardless of motor types (P < .05). CONCLUSIONS: Under the limitations of this study design, the reciprocating NiTi file system may generate greater vibration than the continuous rotation NiTi file systems. The motor type also has a significant effect to amplify the vibrations.

A comparison of dimensional standard of several nickel-titanium rotary files.

OBJECTIVES: The aim of this study was to compare the dimensional standard of several nickel-titanium (Ni-Ti) rotary files and verify the size conformity. MATERIALS AND METHODS: ProFile (Dentsply Maillefer), RaCe (FKG Dentaire), and TF file (SybronEndo) #25 with a 0.04 and 0.06 taper were investigated, with 10 in each group for a total of 60 files. Digital images of Ni-Ti files were captured under light microscope (SZX16, Olympus) at 32×. Taper and diameter at D1 to D16 of each files were calculated digitally with AnalySIS TS Materials (OLYMPUS Soft Imaging Solutions). Differences in taper, the diameter of each level (D1 to D16) at 1 mm interval from (ANSI/ADA) specification No. 101 were statistically analyzed using one-way ANOVA and Scheffe's post-hoc test at 95% confidence level. RESULTS: TF was the only group not conform to the nominal taper in both tapers (p < 0.05). All groups except 0.06 taper ProFile showed significant difference from the nominal diameter (p < 0.05). CONCLUSIONS: Actual size of Ni-Ti file, especially TF, was different from the manufacturer's statements.

Chronic maxillary sinusitis caused by root canal overfilling of Calcipex II.

This is a case report of chronic maxillary sinusitis caused by root canal overfilling of Calcipex II (Techno-Dent). A 60 year-old male complained of dull pain in the right maxillary molar area after complicated endodontic treatment using Calcipex II paste and was finally diagnosed with a chronic maxillary sinusitis through a clinical and radiological observation. In the biopsy examination, the periapical granuloma contained a lot of dark and translucent Calcipex II granules which were not stained with hematoxylin and eosin. They were usually engulfed by macrophages but rarely resorbed, resulting in scattering and migrating into antral mucosa. Most of the Calcipex II granules were also accumulated in the cytoplasms of secretory columnar epithelial cells, and small amount of Calcipex II granules were gradually secreted into sinus lumen by exocytosis. However, chronic granulomatous inflammation occurred without the additional recruitment of polymorphonuclear leukocytes (PMNs) and lymphocytes, and many macrophages which engulfed the Calcipex II granules were finally destroyed in the processes of cellular apoptosis. It is presumed that Calcipex II granules are likely to have a causative role to induce the granulomatous foreign body inflammation in the periapical region, and subsequently to exacerbate the chronic maxillary sinusitis in this study.

Accuracy of Root ZX in teeth with simulated root perforation in the presence of gel or liquid type endodontic irrigant.

OBJECTIVES: To evaluate the accuracy of the Root ZX in teeth with simulated root perforation in the presence of gel or liquid type endodontic irrigants, such as saline, 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine liquid, 2% chlorhexidine gel, and RC-Prep, and also to determine the electrical conductivities of these endodontic irrigants. MATERIALS AND METHODS: A root perforation was simulated on twenty freshly extracted teeth by means of a small perforation made on the proximal surface of the root at 4 mm from the anatomic apex. Root ZX was used to locate root perforation and measure the electronic working lengths. The results obtained were compared with the actual working length (AWL) and the actual location of perforations (AP), allowing tolerances of 0.5 or 1.0 mm. Measurements within these limits were considered as acceptable. Chi-square test or the Fisher's exact test was used to evaluate significance. Electrical conductivities of each irrigant were also measured with an electrical conductivity tester. RESULTS: The accuracies of the Root ZX in perforated teeth were significantly different between liquid types (saline, NaOCl) and gel types (chlorhexidine gel, RC-Prep). The accuracies of electronic working lengths in perforated teeth were higher in gel types than in liquid types. The accuracy in locating root perforation was higher in liquid types than gel types. 5.25% NaOCl had the highest electrical conductivity, whereas 2% chlorhexidine gel and RC-Prep gel had the lowest electrical conductivities among the five irrigants. CONCLUSIONS: Different canal irrigants with different electrical conductivities may affect the accuracy of the Root ZX in perforated teeth.

Overfilling of calcium hydroxide-based paste Calcipex II produced a foreign body granuloma without acute inflammatory reaction.

A patient, a 62-year-old man, received endodontic treatment of the lower left canine complicated by apical overfilling of Calcipex II. At the second day after the root canal filling, the 14th day after placement of Calcipex II intracanal medication, he complained of a gingival swelling in the treated area. The incisional biopsy of the gingival swelling revealed a foreign body granuloma infiltrated with macrophages engulfing the fine Calcipex II granules but with polymorphonuclear leukocytes (PMNs). However, the gingival swelling was healed uneventfully, and the tooth was free of symptoms at 4 months' follow-up. This study first reports the Calcipex II-induced reaction in human periodontium. In the immunohistochemistry using antisera of lysozyme, CD31, CD68, interleukin-8 (IL-8), and poly(ADP-ribose) polymerase 1 (PARP-1), the granule-laden cells are positive for lysozyme, CD31, CD68, and PARP-1, but negative for IL-8. Thus, it is presumed that the granule-laden cells belong to the macrophages/monocytes rather than the PMNs, and that they gradually undergo the apoptotic processes. These data suggest that the canal dressing material, Calcipex II, is able to be widely dispersed into the periodontal tissues, primarily engulfed by macrophages, and resulted in the foreign body granuloma in the absence of acute inflammatory reaction.