Iranian Endodontic Journal
Volume:14 Issue: 4, Fall 2019

It has been shown that the mechanical and physical properties of Calcium Enriched Mixture (CEM) cement are influenced by the mixing methods. Despite several studies conducted on different mixing methods of CEM cement, there is no systematic review to summarize the results. This systematic review was conducted to investigate the effect of different mixing techniques on mechanical and physical characteristics of CEM cement. Methods and Materials: A professional librarian with skills in informatics conducted a systematic search by searching electronic databases PubMed/MEDLINE and Scopus and Ovid for English language peer-reviewed articles published between 1992 and April 2019.

Initial searches from all sources identified 1175 references. Two of the authors examined the titles, abstracts of these articles and the full reports of 20 studies were obtained, and data extraction was performed. Seven studies satisfied the eligibility criteria for the review. The effect of different mixing methods was investigated on bacterial microleakage, push-out bond strength, flow rate, compressive strength, solubility, pH, film thickness, dimensional changes, working time, setting time and quality of the apical plug.

Based on the results of this systematic review, some of the important properties of CEM cement were affected by different mixing methods. Although none of these mixing methods could improve all the properties, mechanical and manual methods were more effective compared to ultrasonic method.  

Phentolamine mesylate (OraVerse) is mostly used to reverse soft tissue anesthesia after dental procedures. The aim of the present study was to evaluate the effect of the injection of OraVerse on postoperative pain after root canal treatment in patients with symptomatic irreversible pulpitis. Methods and Materials: In this randomized single-blind clinical trial study, 100 patients (50 per group) with symptomatic irreversible pulpitis in the first or second mandibular molars, randomly received either OraVerse or sham treatment after a single-visit root canal therapy. Each patient recorded their pain score, using a Heft Parker visual analogue scale, before and after 6, 12, 24, 36, 48, and 72 h of the treatment. They also monitored their soft-tissue anesthesia every 15 min for 5 h. Data were analyzed by t-test and repeated measured ANOVA statistical tests. The level of significance was set at 0.05.

Patients who received phentolamine had significantly higher pain scores at 6- and 12-h postoperative intervals compared with those receiving sham treatment (P=0.01 and P=0.00 respectively). Consumption of analgesics in OraVerse group was significantly higher than that of the sham group (P=0.48).

Although phentolamine accelerated the reversal of normal soft tissue sensation after the dental visit, it increased postoperative pain in patients suffering from symptomatic irreversible pulpitis, which may limit phentolamine administration in this group.

Successful outcome of pulp capping treatment using mineral trioxide aggregate (MTA), often leads to tooth discoloration. This study aimed to compare the efficacy of external bleaching technique with three bleaching agents naming hydrogen peroxide, carbamide peroxide and sodium perborate for correction of tooth discoloration caused by MTA. Methods and Materials: This in vitro, experimental study used 36 tooth blocks prepared from 12 bovine central incisors. White ProRoot MTA was applied in cavities; drilled in blocks for 40 days to cause discoloration. Then, the blocks were assigned to three experimental groups (n=12). Following application of hydrogen peroxide, carbamide peroxide and sodium perborate, the color parameters were determined at baseline and at 1, 7 and 14 days, using a spectrophotometer. Data were analyzed using repeated measure ANOVA and Tukey’s test.

No significant difference was noted in color change (∆E) immediately after bleaching with hydrogen peroxide and carbamide peroxide (P>0.05). However, these two groups had significant differences in ∆E with the sodium perborate group (P=0.001). Hydrogen peroxide group showed significantly higher ∆E at 1 week compared with other groups (P=0.01). The three groups were significantly different in ∆E at 2 weeks after bleaching (P=0.001). Pairwise comparisons revealed no significant difference between sodium perborate and carbamide peroxide in ∆E but they both had a significant difference with hydrogen peroxide (P=0.01).

The three bleaching agents bleached the discoloured teeth effectively. Hydrogen peroxide had the highest efficacy whilst sodium perborate and carbamide peroxide had lower but similar efficacy.

Health of periapical tissues has been considered as an index for the evaluation of endodontic outcomes. The present study sought to assess the pattern of periapical lesion extension in anterior teeth using cone-beam computed tomography (CBCT). Methods and Materials: In this descriptive study‚ 199 CBCT images belonged to patients aging from 15 to 79 were assessed according to periapical lesion extension in the regions of maxillary and mandibular anterior teeth. Maximum periapical lesion extensions in three orthogonal planes were measured and recorded in millimeters and were assessed according to age‚ gender‚ dental arch and tooth type. Statistical analysis was performed using percentages‚ repeated measure ANOVA and Bonferroni tests. The significant level was set at 0.05.

The highest average of lesion extension, in both maxilla and mandible, was in vertical dimension‚ followed by horizontal buccolingual and horizontal mesiodistal dimensions‚ respectively. There were significant differences between the vertical and mesiodistal (P=0.004) and also mesiodistal and buccolingual (P=0.010) periapical lesion extension dimensions. In addition, there were significant differences in maxilla and mandible (P=0.012). In maxilla, there were no significant differences between the three tooth types (P=0.346) but in the mandibular arch, there were significant differences between central-canine (P=0.004) and lateral-canine (P=0.026). According to independent variables, only gender had a significant effect on the lesion extension in anterior regions of maxilla and mandible (P=0.001). The periapical lesion extensions were significantly higher in men compared with women.

The bone destruction_as a consequence of periapical inflammatory process_ was greatest in the vertical, and lowest in the horizontal mesiodistal dimensions. That way, the extension in buccolingual dimension, which could not be detected in the 2-D imaging techniques, was rather high in the present study. Thus CBCT, as a 3-D imaging technique, could be recommended for the precise evaluation of lesion extension in the periapical area.

Mineral trioxide aggregate (MTA) is extensively used in endodontics. However, it has limitations such as long setting time, low compressive strength and poor handling properties. Our study aimed to compare the setting time and surface microhardness of MTA and fluoride-doped MTA (FMTA) using gel-like polymer (GLP) or distilled water (DW) as liquid. Methods and Materials: An MTA-like cement was prepared by mixing Portland cement, bismuth oxide and gypsum (75%, 20% and 5%, respectively). FMTA (1% and 5%) was made by substituting 1% and 5% of MTA powder with fluoride. GLP, composed of methyl cellulose (MC) and propylene glycol (PG), was used as the hydrating liquid and compared with distilled water. Six experimental groups (n=10) were examined for each test. The samples were subjected to Vickers surface microhardness test after 4 and 28 days. Setting time was measured using ANSI/ADA standards. Data was analyzed using two-way and repeated measured ANOVA and the Tukey HSD tests.

The MTA-like cement hydrated with GLP showed a significantly reduced setting time (P<0.05); 1% FMTA, mixed with GLP, had the shortest initial and final setting times. The microhardness values of all samples increased at different rates during 28 days (P<0.00001). The microhardness significantly decreased by addition of fluoride to MTA (P<0.001).

The results of the present in vitro study suggested that using GLP as the hydrating liquid enhances the setting time with no adverse effect on the surface microhardness. However, adding fluoride can negatively affect the microhardness of MTA.

Knowledge about root canal anatomy improves the long-term prognosis of endodontic treatment. This study aimed to investigate the accuracy of cone-beam computed tomography (CBCT) in assessment of morphology of root canal and apex in mandibular canines compared with the clearing technique. Methods and Material: In this in vitro study, 33 extracted mandibular canines were subjected to CBCT with 0.1 mm voxel size. Number and type of canals, prevalence of accessory canals, anastomosis, apical delta and distance from apical constriction (AC) to apical foramen (AF) and to anatomic apex (AA) and also distance from AF to the AA were determined on CBCT scans. After access cavity preparation, a #8 K file was passed through the main apical foramen. Its direction and distance from anatomic apex was determined under a stereomicroscope. After clearing and staining of teeth, other criteria were determined with stereomicroscope under 16× magnification and served for comparison with CBCT data. The agreement of two methods were evaluated by intra-class correlation and kappa coefficients for quantitative and qualitative data, respectively.

Most (93.9%) canine teeth were Vertucci’s type I, followed by type III configuration in both CBCT and clearing techniques. The results of both techniques were not in agreement for assessment of accessory canals, however acceptable agreement was noted between them for detection of apical delta and also assessment of apical foramen deviation in buccolingual and mesiodistal directions. Both of two techniques had excellent agreement for evaluating the distances from AF to AA, AC to AF and AC to AA.

CBCT is a reliable tool in assessment of root canal and apical topography in mandibular canines, however its use in accessory canal detection is not recommended.

Apex locators are important devices that can be used to determine working length during root canal treatment. However, it is not known whether electronic devices with various wave length frequencies influence the accuracy of apex locators. The aim of this study was to determine whether a cordless phone set, MP4 player, FM radio, asymmetric digital subscriber line (ADSL), or a mobile phone could influence the accuracy of working length determination by the Dentaport ZX apex locator. Methods and Materials: In this study, twenty-four sound intact single-rooted extracted human teeth were used. After determining the root canal length with a file and a microscope, the canals were measured with three separate Dentaport ZX apex locators while one of the test devices (ADSL, MP4, FM radio, mobile phone, and cordless phone) was used at a distance of 50 cm from the apex locator. Bland–Altman plots was used for reliability and consistency.

Except for the FM radio, all other devices showed significant difference with actual working length (P<0.05). ADSL and MP4 player showed the least consistency compared to the other devices.

Based on this in vitro study, the use of ADSL, MP4 player, mobile phone, and cordless phone during root canal treatment may influence working length determination with the Dentaport ZX apex locator.

Adequate knowledge about the anatomy of the roots and canals of mandibular third molars is imperative for a successful treatment. This study aimed to use cone-beam computed tomography (CBCT) to evaluate the morphology of the roots and canals of mandibular third molars and their symmetry. Methods and Materials: Totally, 110 CBCT images of bilateral mandibular third molars were evaluated in terms of the number of roots and canals, canal type, isthmus location, location of accessory canals, degree of root curvature and its direction, age and sex of patients and the symmetry of variables in the right and left sides of the mandible. The descriptive statistics, t-test and chi-square test were applied to analyze data.

Of all, 71.36% of mandibular third molars had two roots, 20.9% had one single root and 7.72% had three roots. The distal root had one single canal in 89.08%. The mesial root had one single canal in 44.25% and two canals in 49.42%. The Vertucci’s types I (45.40%) and IV (34.48%) had the highest frequency in the mesial root while type I (91.95%) had the highest frequency in the distal root. The deviation of mesial root was towards the distal while distal roots were mainly straight.

The symmetry between the right and left mandibular third molars was significantly high. In case of encountering anatomical complexities in dental treatment of a mandibular third molar, dental clinicians should consider the high possibility of presence of the same condition in the contralateral mandibular third molar.

This study aimed to compare the effects of different agitation techniques of sodium hypochlorite (NaOCL) as the final irrigation with XP-Finisher file, passive ultrasonic irrigation (PUI), Er:YAG laser and irrigation with conventional syringes, on penetration of Sure Seal Root bioceramic sealer into dentinal tubules. Methods and Materials: Forty freshly extracted single-rooted human teeth were included in the present in vitro study. All the teeth were prepared up to #40 (4%) with Bio Race rotary file system, using crown-down technique. After chemomechanical preparation, the teeth were randomly assigned to 4 groups based on the agitation protocol: conventional needle irrigation (CNI) with a 30-G needle in a syringe, PUI, Er:YAG laser and XP-Finisher file, Subsequent to the agitation procedure, the root canals were obturated with tapered bioceramic-covered gutta-percha point and, bioceramic sealer, using the single-cone technique. The maximum penetration of the sealer into the dentinal tubules was determined in the coronal, middle and apical thirds using the scanning electron microscope (SEM) technique. After confirmation of the normal distribution of data with Shapiro-Wilk test, Data were analyzed using the one-way ANOVA and Tukey tests.

The mean penetration depth of the bioceramic sealer into the dentinal tubules in the PUI group was greater than that of other groups; however, the difference between the two PUI and Er:YAG laser groups in the apical third was not significant (P=0.078). Er:YAG laser, PUI and XP-Finisher file agitation techniques resulted in significantly greater penetration of the bioceramic sealer into the dentinal tubules compared to the CNI (P<0.001). The XP-Finisher file technique in the apical (P=0.752) and middle thirds (P=0.339) and the Er:YAG laser technique in the apical thirds (P=0.086) were not significantly different from the conventional irrigation technique.

The PUI technique resulted in significantly deeper penetration of the Bioceramic sealer into the dentinal tubules compared to the three other techniques. 

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. Methods and Materials: 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.

The management of necrotic immature permanent teeth, with blunderbuss root anatomy, is a treatment challenge. Treatment protocols include root canal apexification, creation of an apical plug and recently, regeneration and revascularization protocol (RRP). The latter may have the advantage of continued root development. The main purpose of this case series was to describe the RRP of three necrotic immature permanent mandibular molars with open apices. RRP involved accessing the pulp chamber, disinfecting the root canal system with copious irrigation using 2.5% sodium hypochlorite, applying triple antibiotic paste/calcium hydroxide as an intracanal medicament and sealing the access cavity. After three weeks, the medicament was removed and the apex was irritated with a K-file to induce blood-clot formation inside the pulp canal space; which would provide a suitable matrix for new tissue in-growth. Mineral trioxide aggregate was employed to seal the canal orifices before final restoration. During follow-up sessions, patients were asymptomatic and root development seemed to be in progress. Therefore, it seems that with proper case selection, regeneration and revascularization can be considered as a suitable alternative for the apexification of necrotic immature teeth.

This study aimed to present a case series of refractory endodontic treatment leading to persistent apical periodontitis. All cases were submitted to scanning electron microscopic/energy-dispersive X-ray analysis (SEM/EDS) of the external surface of the surgically removed samples and identification of the elements present in the specimens. Carbon, oxygen and calcium were elements present in all of the cases in this study. The presence of microorganisms in close contact with the periapical surrounding tissues induced the perpetuation of the inflammation process. Despite the presence of other elements different from those normally expected in the tissues, we may not attribute any interference in the periapical response to them.