Original Article

Effect of Smear Layer on the Push-Out Bond Strength of Two Endodontic Biomaterials to Radicular Dentin

Mehrdad Lotfi, Negin Ghasemi, Saeed Rahimi, Mahmood Bahari, Sepideh Vosoughhosseini, Mohammad Ali Saghiri, Vahid Zand

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 41-44

Introduction: This in vitro study was designed to evaluate the effect of smear layer removal on push-out bond strength of white mineral trioxide aggregate (WMTA) and calcium-enriched mixture cement (CEM). Materials and Methods: Dentin discs with 3 mm thicknesses were divided into 4 groups (n=15): group 1: irrigation of the canal with normal saline and filling with WMTA; group 2: irrigation with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA), and then filling with WMTA; group 3: same as group 1 but the lumens were filled with CEM; group 4: same as group 2 but the lumens filled with CEM. The samples were incubated at 37°C for 3 days after wrapping in gauze pieces moistened with distilled water. The push-out bond strengths were then measured by the universal testing machine and the failure modes were examined under a stereomicroscope at 40× magnification. Data were analyzed using two-way ANOVA and post-hoc Tukey’s test for bond strength. Statistical significance was set at P<0.05. Results: The greatest and lowest mean standard deviation for push-out bond strength were observed for groups 4 (3.13±1.46 MPa) and group3 (1.44±0.96 MPa), respectively. The effect of smear layer removal on push-out bond strength of CEM was significant (P=0.01), however, it was not significant for WMTA (P=0.52). The failure mode for all the groups was of mixed type. Conclusion: Under the limitations of this study, smear layer removal is recommended for CEM in order to gain higher push-out strength.

Mineral Trioxide Aggregate Mixed with Normal Saline, Calcium Chloride or KY Jelly as Apical Plug in Simulated Open Apices: An In vitro Microleakage Study

Payman Mehrvarzfar, Hengameh Akhavan, Sara Ghasemi, Fatemeh Khodaei, Sohrab Tour Savadkouhi, Omid Dianat

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 45-49

Introduction: Mineral trioxide aggregate (MTA) mixed with normal saline has short working time, delayed setting time, and poor consistency when used as an apical plug. A preliminary study suggested that substituting normal saline with KY Jelly or 5% calcium chloride (CaCl2) as a vehicle expedites the setting time of MTA. The present in vitro study compared the microleakage of ProRoot MTA mixed with normal saline (MS) to that of ProRoot MTA mixed with KY Jelly and/or 5% CaCl2 in simulated canals with open apices. Materials and methods: Thirty six single-rooted extracted human teeth were cleaned and shaped with ProTaper rotary system to make 36 standardized artificially created open apices. Teeth were randomly divided into three experimental groups (n=10) and two control groups (n=3). In group 1, MTA was mixed with normal saline (MS) and placed into the canals to form 4 to 5 mm apical plugs. In group 2, MTA was mixed with 5% CaCl2 (MC) and in group 3, MTA was mixed with KY Jelly (MK). The other two groups served as positive and negative controls. The remaining canal spaces in the experimental groups were backfilled with thermoplasticized gutta-percha without sealer. Dye penetration and clearing was used to evaluate the sealing ability of each group. The samples were then examined under stereomicroscope to measure the microleakage of different MTA mixtures in mm. Data were statistically analyzed using One-Sample Kolmogorov-Smirnov test for determination of normal distribution and then by one-way ANOVA and Tukey’s tests to detect any significance. Results: Positive and negative controls responded as expected. The MS group showed the least mean dye penetration value. There was a significant difference between MS with other groups (P<0.05) but no difference was found between MC and MK groups. Conclusion: Within the limitations of this in vitro study, we can conclude that among these three vehicles, normal saline mixed with ProRoot MTA has the least amount of microleakage in canals with open apices.

A Histological Comparison of a New Pulp Capping Material and Mineral Trioxide Aggregate in Rat Molars

Fariborz Moazzami, Yasmin Ghahramani, Ali Mohammad Tamaddon, Ali Dehghani Nazhavani, Alireza Adl

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 50-55

Introduction: Recent investigations have attempted to improve regenerative endodontics with the help of stem cell therapy. In vitro studies have shown the ability of different agents to stimulate the differentiation of dental pulp stem cells (DPSC) into odontoblast-like cells. A combination of dexamethasone, β-glycerophosphate and Vitamin D has been proven to induce a successful differentiation. The aim of this animal study was to evaluate the effect of this combination, named odontoblastic differentiating material (ODM), on pulp tissue when used as a capping material. Materials and Methods: Sixty maxillary right and left molars of 30 Sprague-dawley rats were selected for this study. The teeth were exposed under sterile condition. Half of the teeth were capped with mineral trioxide aggregate (MTA) and the other half with ODM. All cavities were restored with glass ionomer. The rats were sacrificed at post-operative intervals of 2 weeks and 2 months. Samples were histologically evaluated for the degree of inflammation and reparative dentin formation. Finally the data was analyzed with Mann-Whitney and Chi-Square tests. Results: Reparative dentin formed in all groups within both time periods and there was no statistically significant difference between the groups in the mentioned time periods. The MTA group, however, showed a statistically significant reduction in inflammation at both time intervals (P<0.05). Compared to MTA, ODM samples showed a greater amount of inflammation in the pulp tissue. Conclusion: ODM, as a pulp capping material, can induce dentinal bridge formation.

Sample Size Calculation of Clinical Trials Published in Two Leading Endodontic Journals

Arash Shahravan, Ali-Akbar Haghdoost, Maryam Rad, Maryamalsadat Hashemipoor, Maryam Sharifi

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 56-60

Introduction: The purpose of this article was to evaluate the quality of sample size calculation reports in published clinical trials in Journal of Endodontics and International Endodontic Journal in years 2000-1 and 2009-10. Materials and Methods: Articles fulfilling the inclusion criteria were collected. The criteria were: publication year, research design, types of control group, reporting sample size calculation, the number of participants in each group, study outcome, amount of type I (α) and II (β) errors, method used for estimating prevalence or standard deviation, percentage of meeting the expected sample size and considering clinically importance level in sample size calculation. Data were extracted from all included articles. Descriptive analyses were conducted. Inferential statistical analyses were done using independent T-test and Chi-square test with the significance level set at 0.05. Results: There was a statistically significant increase in years between 2009 and 10 compared to 2000-1 in terms of reporting sample size calculation (P=0.002), reporting clinically importance level (P=0.003) and in samples size of clinical trials (P=0.01). But there was not any significant difference between two journals in terms of reporting sample size calculation, type of control group, frequency of various study designs and frequency of positive and negative clinical trials in different time periods (P>0.05). Conclusion: Sample size calculation in endodontic clinical trials improved significantly in 2009-10 when compared to 2000-1; however further improvements would be desirable.

The Effect of Size and Taper of Apical Preparation in Reducing Intra-Canal Bacteria: A Quantitative SEM Study

Nahid Mohammadzadeh Akhlaghi, Nahid Rahimifard, Amirabbas Moshari, Mehdi Vatanpour, Soheila Darmiani

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 61-65

Introduction: Bacteria and their byproducts are major etiologic factors in endodontic diseases. Prevention or reduction of root canal bacterial contamination is the main aim of endodontic treatment. The purpose of this in vitro study was to evaluate the effect of size and taper of master apical file (MAF) in reducing bacteria from the apical third of the curved canals using a quantitative scanning electron microscope (SEM) study. Methods and Materials: Eighty-nine human mandibular first molars with curved MB canals (20º-35º) were divided into one control group (n=5) (without rotary instrumentation) and 6 experimental groups (n=14). The canals were prepared using RaCe rotary files to the MAF sizes 25/0.04, 25/0.06, 30/0.04, 30/0.06, 35/0.04 and 35/0.06, in groups 1 to 6, respectively. All the experimental groups were finally rinsed with 2 mL of 17% EDTA followed by 3 mL of 5.25% NaOCl. The mesial roots were split longitudinally. Remaining bacteria in the apical third of MB canals were evaluated using SEM (2000×). Data analysis was performed using one way ANOVA with Tukey’s post hoc test. The level of significance was set at 0.05. Results: All the experimental groups showed significant bacterial reduction (P<0.001). Although the greater size and/or taper resulted in decrease in bacteria, differences between the groups were not significant. Conclusion: Based on this in vitro study the MAF #25/0.04 had no significant difference compared to other groups with greater apical size/taper; all groups could effectively reduce intra-canal bacteria.

Quality of Root Canal Obturation Performed by Senior Undergraduate Dental Students

Saeed Moradi, Maryam Gharechahi

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 66-70

Introduction: There is a direct relationship between the quality of root canal obturation and success of endodontic therapy. The aim of the present study was to assess the quality of canal obturation performed by undergraduate dental students at the Faculty of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran. Materials and Methods: Records of 200 endodontically treated teeth from patients who were visited by undergraduate students between 2009 and 2010, at the Endodontic department, Faculty of Dentistry, Mashhad University of Medical Sciences, were randomly selected for evaluation. Periapical radiographs of all treated teeth were assessed in terms of canal obturation quality (i.e. adequate density and length). Statistical analysis of data was carried out using SPSS software and chi-square test. The Statistical significance level was set at P=0.05. Results: Forty-five percent of teeth fulfilled the criteria of an acceptable root canal obturation. Adequate length and density of root filling was found in 89% and 34% of teeth, respectively. There was a significant difference between maxillary and mandibular teeth regarding the length of root canal obturation (P=0.004). A significant difference was observed between molars and other tooth types. The frequency of root canals with an acceptable filling was significantly greater in the anterior teeth compared to premolars or molars. Conclusion: The technical quality of root canal treatment performed by undergraduate dental students was found to be less than ideal.

Case Report

Indications and Case Series of Intentional Replantation of Teeth

Saeed Asgary, Laleh Alim Marvasti, Alireza Kolahdouzan

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 71-78

This case series aims to comprehensively introduce intentional replantation with a focus on its indications and case selection in endodontics. In all represented cases, calcium enriched mixture (CEM) cement is used for root-end filling. This case series demonstrates twenty cases of IR and extraoral root-end resection and filling with CEM cement. All the selected teeth had a failed endodontic treatment and required surgical/nonsurgical endodontic (re)treatment or extraction. Subsequent to gentle tooth extraction, an appropriate root-end cavity was prepared and filled with CEM cement. Then the tooth was replanted; maximun procedure time was 15 min. A total of 18 cases (90%) were successful over a mean follow-up period of 15.5 months. It can be concluded that intentional replantation with careful case selection can have a high success rate over 2 years. Intentional replantation may be a suitable treatment option for both trained general practitioners and specialists provided that the extraction is simple and straightforward.

Repair of an Extensive Furcation Perforation with CEM Cement: A Case Study

Mohammad Jafar Eghbal, Mahta Fazlyab, Saeed Asgary

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 79-82

Iatrogenic perforation of the furcation area in multi-rooted molars during preparation of the access cavity can potentially lead to tooth extraction. The present case report describes the nonsurgical endodontic management of an extensive pulp chamber floor perforation in a first mandibular molar with calcium enriched mixture (CEM) cement. The perforation was chemically cleaned and then physically sealed with CEM cement. Root canal therapy was completed and the tooth was then restored with amalgam. A one-year follow-up revealed the absence of symptoms of infection/inflammation as well as clinical and radiographic signs/symptoms and therefore, can be interpreted as a favorable treatment outcome.

Review Article

Various Strategies for Pain-Free Root Canal Treatment

Masoud Parirokh, Paul V. Abbott

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 1-14

Introduction: Achieving successful anesthesia and performing pain-free root canal treatment are important aims in dentistry. This is not always achievable and therefore, practitioners are constantly seeking newer techniques, equipments, and anesthetic solutions for this very purpose. The aim of this review is to introduce strategies to achieve profound anesthesia particularly in difficult cases. Materials and Methods: A review of the literature was performed by electronic and hand searching methods for anesthetic agents, techniques, and equipment. The highest level of evidence based investigations with rigorous methods and materials were selected for discussion. Results: Numerous studies investigated to pain management during root canal treatment; however, there is still no single technique that will predictably provide profound pulp anesthesia. One of the most challenging issues in endodontic practice is achieving a profound anesthesia for teeth with irreversible pulpitis especially in mandibular posterior region. Conclusion: According to Most investigations, achieving a successful anesthesia is not always possible with a single technique and practitioners should be aware of all possible alternatives for profound anesthesia.

New Approaches in Vital Pulp Therapy in Permanent Teeth

Jamileh Ghoddusi, Maryam Forghani, Iman Parisai

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 15-22

Vitality of dental pulp is essential for long-term tooth survival. The aim of vital pulp therapy is to maintain healthy pulp tissue by eliminating bacteria from the dentin-pulp complex. There are several different treatment options for vital pulp therapy in extensively decayed or traumatized teeth. Pulp capping or pulpotomy procedures rely upon an accurate assessment of the pulp status, and careful management of the remaining pulp tissue. The purpose of this review is to provide an overview of new approaches in vital pulp therapy in permanent teeth.

Health Technology Assessment of CEM Pulpotomy in Permanent Molars with Irreversible Pulpitis

Shahram Yazdani, Mohammad-Pooyan Jadidfard, Bahareh Tahani, Ali Kazemian, Omid Dianat, Laleh Alim Marvasti

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 23-29

Introduction: Teeth with irreversible pulpitis usually undergo root canal therapy (RCT). This treatment modality is often considered disadvantageous as it removes vital pulp tissue and weakens the tooth structure. A relatively new concept has risen which suggests vital pulp therapy (VPT) for irreversible pulpitis. VPT with calcium enriched mixture (VPT/CEM) has demonstrated favorable treatment outcomes when treating permanent molars with irreversible pulpitis. This study aims to compare patient related factors, safety and organizational consideration as parts of health technology assessment (HTA) of the new VPT/CEM biotechnology when compared with RCT. Materials and Methods: Patient related factors were assessed by looking at short- and long-term clinical success; safety related factors were evaluated by a specialist committee and discussion board involved in formulating healthcare policies. Organizational evaluation was performed and the social implications were assessed by estimating the costs, availability, accessibility and acceptability. The impact of VPT/CEM biotechnology was assessed by investigating the incidence of irreversible pulpitis and the effect of this treatment on reducing the burden of disease. Results: VPT/CEM biotechnology was deemed feasible and acceptable like RCT; however, it was more successful, accessible, affordable, available and also safer than RCT. Conclusion: When considering socioeconomic implications on oral health status and oral health-related quality of life of VPT/CEM, the novel biotechnology can be more effective and more efficient than RCT in mature permanent molars with irreversible pulpitis.

Tissue Engineering Considerations in Dental Pulp Regeneration

Ali Nosrat, Jong Ryul Kim, Prashant Verma, Priya S. Chand

Iranian Endodontic Journal, Vol. 9 No. 1 (2014), 24 December 2013 , Page 30-40

Regenerative endodontic procedure is introduced as a biologically based treatment for immature teeth with pulp necrosis. Successful clinical and radiographic outcomes following regenerative procedures have been reported in landmark case reports. Retrospective studies have shown that this conservative treatment allows for continued root development and increases success and survival rate of the treated teeth compared to other treatment options. Although the goal of treatment is regeneration of a functional pulp tissue, histological analyses show a different outcome. Developing predictable protocols would require the use of key elements for tissue engineering: stem cells, bioactive scaffolds, and growth factors. In this study we will review the evidence based steps and outcomes of regenerative endodontics.