Iranian Endodontic Journal
Volume:14 Issue: 3, Summer 2019

The number of patients that return for recall appointments has great importance to validate endodontic treatment outcomes. The purpose of this review was to investigate the rate of return on recall and the main factors that influence this rate of return. A literature review was performed in the PubMed database for the years from 1978 to 2017, using the following keywords: recall rate, endodontic treatment, endodontic retreatment, apical surgery. The inclusion criteria were: prospective studies in English, and in vivo research with humans, which included patient return rates. A total of 35 studies that fulfilled the established criteria were selected. The percentage of patients who returned on recall was 56%. More female patients (60%) attended the recall appointments than male (40%). The three main reasons for not returning were: patients did not observe the follow-up appointment (490), not returning due to a lack of interest (99) and   changing their address (222). The age of the patients attending the appointments varied from 28.6 to 62 years old, with the highest percentage of patients that returned ranging from 40 to 52.5 years old. According to the literature the optimal rate of return for follow-up treatment should be greater than 80%, for the validity of the research. However, the reality presented in the studies is far from ideal. Many studies do not even mention these rates of return in their methodologies or in their results, which may mask the true treatment success rates.

Calcium hypochlorite (CH) has been recently suggested as an endodontic irrigant. The aim of this investigation was to evaluate the antimicrobial efficacy of CH compared to sodium hypochlorite (NaOCl) and chlorhexidine (CHX) against multispecies biofilm in surface and deep dentinal tubules. Methods and Materials: Minimal inhibitory concentration (MIC) of irrigant agents was assessed using a microdilution method. One hundred and twenty of human maxillary incisor teeth were prepared and infected with suspension of Entrococcus faecalis, Fusobacterium nucleatum and Prevotella intermedia in an anaerobic jar for 7 days. Depending on irrigation solutions, specimens were divided into 4 groups (n=30); group 1: 2% CHX, group 2: 5.25% sodium hypochlorite, group 3: 5% calcium hypochlorite, group 4: positive control (normal saline (NS)). Fifteen remained specimens were used as negative control. Surviving bacteria were sampled before (S1) and after irrigation from surface (S2) and deep (S3) dentin. The medium turbidity was visualized with spectrophotometry. Data were analyzed using analysis of variance followed by Tukey post hoc test (α=0.05). The MIC of CH against E. faecalis, F. nucleatum and P. intermedia was 25, 8 and 7.5 µg/mL respectively. There were no significant differences in S1 among the test groups. Moreover, 2% CHX and 5% CH had significantly lower medium turbidity at both S2 and S3, in comparison with 5.25% NaOCl (P=0.018 and 0.031, respectively). But there were no significant differences between 2% CHX and 5% CH at both S2 and S3 (P=0.862 and 0.978, respectively). Under the conditions of this ex vivo study, 5% CH and 2% CHX are more effective than 5.25% NaOCl in the reduction of mixed-culture biofilm.

The aim of this study was to evaluate the effect of different water-to-powder (WP) proportions on the microhardness and water solubility of calcium-enriched mixture (CEM) cement. Methods and Materials: One gram of CEM cement powder was mixed with 0.33 mL, 0.4 mL or 0.5 mL CEM liquid. For water solubility, a total of 60 specimens were prepared (n=20 per each ratio) in the disk-shaped stainless-steel molds with a height of 1.5±0.1 mm and internal diameter of 10.0±0.1 mm. The specimens of each WP ratio were randomly divided into two subgroups: half (n=10) were immersed for one day and the other half (n=10), were kept for 21 days in distilled water. The solubility was calculated as a percentage of the weight loss. To measure microhardness, a total of 30 samples were prepared (10 per each ratio, n=10). The mixtures were transferred to metallic cylindrical molds with internal dimensions of 6±0.1 mm height and 4±0.1 mm diameters. After 4 days the specimens were subjected to Vicker's test. The data were analyzed using two-way ANOVA and post-hoc Tukey’s tests at a significance level of 0.05. The 0.33 WP ratio showed significantly greater microhardness value (25.98±2.77) compared to 0.4 and 0.5 proportions (P=0.004 and P<0.001 respectively). Significant differences were observed between water solubility values of different WP ratios at both time intervals (P<0.001). At both time intervals, 0.33 and 0.5 WP ratios exhibited the lowest and highest solubility, respectively. According to the results of this in vitro study, higher WP ratios result in lower microhardness and higher water solubility of the CEM cement. Therefore, the 0.33 WP ratio would be the ideal proportion.

This histological study analyzed silk sericin as a potential direct pulp capping biomaterial in contact with pulp and comparing its response to calcium hydroxide. Methods and Materials: Twenty maxillary first molars from Wistar male rats were used, with 60 days of age, between 200 and 300 gr, which were divided in 4 groups (n=5): G1 and G3, controls, capped with calcium hydroxide in 7 and 30 days, respectively; G2 and G4, capped with silk sericin in 7 and 30 days, respectively. Circular cavities were prepared for pulp exposure, where capping materials were applied, being posteriorly restored with glass ionomer cement. After completion of each observation period, the animals were sacrificed and molars were histologically processed for analysis in light microscopy to evaluate presence of necrosis in pulp tissue, inflammatory cells infiltration and tertiary dentin formation. Data analysis was carried out using Kruskal-Wallis and Dunn’s post hoc tests. After 7 days, there was less necrosis and inflammatory cells infiltration in G1 when compared to G2 (P=0.007 and P=0.008, respectively). After 30 days, a sample of G3 induced tertiary dentin formation and G4 showed decrease in inflammation (P=0.041) compared to G2. Among the determined experiment conditions, it was concluded that contact between silk sericin and pulp tissue showed improved inflammatory response throughout treatment and new cells proliferation. However, silk sericin adhibition in pure form did not show capability for induction of tertiary dentin formation.

The aim of this study was to evaluate the effect of addition of nano-silica (SiO2) to mineral trioxide aggregate (MTA) on its setting time and porosity. Methods and Materials: The concentration 8% of nano-silica were prepared and added to the MTA powder. After mixing with water the setting time and porosity were evaluated and compared with pure MTA. Statistical analysis was performed using the t-test. The level of significance was set at 0.001. The mean setting time of MTA+8% nano-silica (9.8±0.78) was significantly lower than MTA (23.3±2.16) (P<0.001). Also the mean porosity by imbibition method in MTA+8% nano-silica (23.49±0.48) was significantly higher than MTA (15.69±2.10) (P<0.001). There was no significant difference in mean porosity by scanning electron microscope (SEM) method in MTA+8% nano-silica (31.26±10.73) and MTA (32.74±5.26) (P>0.001). This in vitro study showed us an addition of 8% of nano-silica to MTA reduced the setting time. Although evaluation by imbibition test showed increasing of porosity in nano-silica MTA compared with pure MTA.

Relining fiber posts using composite resins helps the posts adapt to the anatomical space of the root canals. The aim of this study was to evaluate the effect of composite resin type on the push-out bond strength of anatomical fiber posts to intra canal dentin. Methods and Materials: Forty-eight bovine upper incisors were prepared for post space after root canal therapy and randomly divided in to six groups. Five different types of composite resin (GrandioSO, GrandioSO Heavy Flow, X-tra Fil, X-tra base and everX Posterior) were used for relining the prepared fiber posts. In the control group, the prepared post was cemented into the post space without relining. Cervical, middle and apical cross-sections were achieved from each root and push-out test was conducted at a crosshead speed of 0.5 mm/min. One sample from each group was scanned using a micro-CT scanner which provided views from the apical, middle and coronal thirds. Data were analyzed using Kolmogorov-Smirnov test, repeated measures ANOVA and post hoc tests using SPSS 17 (P<0.05). Statistical analysis showed significant differences in terms of mean push-out bond strengths between different composite resin types and cross-sections (P<0.001). The mean push-out bond strength of the samples relined with Grandio SO composite resin (15.48±2.32) and X-tra Fil Bulk-fill composite resin (14.09±1.98) were significantly higher than that of other groups (P<0.05). The unrelined group had a mean push-out bond strength (5.94±1.45) which was significantly lower than that in other groups (P<0.05). In addition, there was a relationship between cross-sections and composite resin types (P<0.05). This in vitro study showed that the composite resins used for relining can affect the push-out bond strength to intra canal dentin based on their physical and mechanical properties.

The purpose of this study was to compare the high resolution cone-beam computed tomography (CBCT) and standard mode CBCT diagnostic accuracy in internal root resorption with different sites and sizes. Methods and Materials: Eighty single rooted human teeth with visible pulps in periapical radiography were split mesiodistally along the coronal plane. Internal resorption like lesions were created in three areas (cervical, middle and apical) in labial wall of the canals in different diameters. High resolution CBCT (CBCT-H) and standard mode CBCT (CBCT-C) were taken from each tooth. Two observers examined the high resolution CBCT and standard mode CBCT to evaluate the presence of resorption cavities. The data were statistically analyzed and degree of agreement was calculated using Cohen’s kappa (k) values. Data were analyzed by SPSS 20 software and sensitivity, specificity and positive and negative predictive value for both methods were calculated. Data were analyzed using the Mac-Nemar and chi-square tests. The positive predictive value and negative predictive value in CBCT-H was higher than that of CBCT-C, all of which indicates that the CBCT-H diagnostic test is more sensitive and more accurate than CBCT-C. Kappa statistics showed that there is a strong and complete agreement between the CBCT high resolution and reality (kappa: 0.72) and in the Standard CBCT method, a moderate agreement has been obtained with reality (Kappa: 0.45). According to our in vitro study CBCT high resolution has a higher diagnostic accuracy than conventional CBCT.

For a successful root canal treatment, it is critical for a clinician to have complete knowledge of the root canal morphology. There are numerous cases in literature concerning the unusual anatomy of mandibular first molars. This report presents a case of a mandibular first molar with three distal canals. An overview of the types and numbers of the common anatomic forms of this tooth also is presented, as is a summary of published anomalies.Key words: Distal Root; Mandibular First Molar; Root Canal Anatomy

Cervicofacial subcutaneous emphysema (CFSE) is a rare complication. CFSE may happen following some dental procedures including root canal therapy and is caused by unintentional entry of air into potential spaces of head and neck. In the current report, a case of extensive bilateral subcutaneous emphysema -following the root perforation of a maxillary anterior tooth- is presented. A 26-year-old woman was referred for further consultation concerning her right maxillary lateral incisor; for which a poor prognosis was considered following an endodontic treatment. There was a history of sudden facial swelling during root canal therapy. With the exacerbation of the problem and experiencing other symptoms, she was hospitalised. CT scan showed bilateral extension and penetration of air into submandibular, peri-orbital and parapharyngeal spaces. Clinical and radiographic evaluations of the maxillary lateral incisor revealed mid-root perforation on its buccal side, which was sealed by MTA. Eventually, the tooth was successfully restored.

Having a thorough knowledge of root canal configuration is essential for a successful endodontic treatment. Clinicians should always pay attention to the unusual canal configuration so as to avoid missing extra canals. This paper describes a non-surgical retreatment of a maxillary second molar with two missing root canals; diagnosed by cone-beam computed tomographic (CBCT) imaging. The tooth had three roots and five canals: a C-shaped buccal root fused by mesiobuccal (MB) and distobuccal (DB) roots with three canals (CBCT scanning showed that the second MB canal was closer to the palatal than the buccal side), a mesiopalatal root with one canal, and a distopalatal root with one canal. The purpose of this case report is to remind clinicians of the importance of anatomical variations, and thus, detection of extra canals.

This article describes the diagnosis and treatment of bilaterally maxillary first molars with two canals in their distobuccal roots. A 13-year-old male came to the clinic with a severe pain of tooth #14. In the first session, after access and finding the main canals and the second mesio-buccal (MB2) canal, another canal was noticed in the distobuccal root. All teeth were examined and a severe decay was observed in the left maxillary first molar. After preparing the access cavity, another orifice was found between the palatal and distobuccal canals. The presence of the second distobuccal canal was confirmed using an apex locator and radiography.

The failures in endodontic treatments are often related to anatomical variations. Some anatomical changes in anterior teeth occur in patients with cleft lip and palate. This paper aims to report the endodontic retreatment of a maxillary central incisor with two roots and two canals on a patient who presents cleft lip and palate. A male patient, 11-year-old, reported pain when chewing related to the left maxillary central incisor tooth (tooth 21) which featured a sinus tract after primary endodontic treatment. In periapical radiograph, it was observed an alteration on the anatomy of the root on the tooth 21, which featured a radiolucent area on the dental apex and had been properly endodontically treated. In cone-beam computed tomography (CBCT) images the presence of an accessory root in the palatal region was observed, that had not been prepared, or filled. Thus, the non-treated accessory canal was instrumented with the crown-down technique and filled with gutta-percha and endodontic sealer. After 1 year of follow-up, the patient presented the tooth with a normal masticatory function and no painful symptoms. Therefore, it can be concluded that the additional root canals may be present and the CBCT is an important tool to evaluate the internal root morphology. In cleft lip and palate patients, the root canals morphology should be carefully analyzed due to high prevalence of dental anomalies which may influence the success in endodontic treatment