Prediction of root canal lengths and pulp volume of the maxillary permanent first molar based on stature, crown diameters, and facial morphometry

This study purposed to develop statistical models to predict palatal (PRL), mesial (MRL), and distal (DRL) root canal length and pulp volume (PV) of the maxillary first permanent molar using stature, gender, mesiodistal (MD), and buccopalatal (BP) crown diameters and some facial morphometries. 57 individuals were included in the study. Cone beam computed tomography was used to measure root canal lengths and PV. The PV calculation was carried out using the software ITK-SNAP 3.4.0. PRL was positively correlated with BP, stature, middle facial height, interalar distance, and bicommissural distance (BCD) (p < 0.05). DRL was positively correlated with BP, MD, and stature (p < 0.05). MRL was positively correlated with BP, MD, stature, lower face height, bizygomatic distance, and BCD (p < 0.05). PV was negatively correlated with age and BCD (p < 0.05). Although all models have significant predictive power for the root lengths and PV, no model could explain variances greater than 30%. The highest and lowest predictive ability was obtained for PRL and DRL, respectively. While the most significant predictor was BP for PRL and DRL, it was the age for PV.

Endodontic Management of a Maxillary Central Incisor with two Roots: A Case Report and Literature Review

Maxillary incisors are typically straightforward cases for root canal therapy. While it is commonly assumed that maxillary central incisors have a single root canal, they may occasionally exhibit variations in their root canal system anatomy. In this report, we present a case of a maxillary central incisor with multiple root canals and provide a review of relevant literature on this anatomical variation. A 13-year-old female with deep carious lesion in tooth 11 was admitted in Department of Endodontics. Following a precise clinical and radiographic examination, a maxillary central incisor with necrotic pulp and chronic apical periodontitis along with unusual root anatomy was found and considered for non-surgical root canal treatment. Successful treatment results depend on various factors and awareness of root canal system anatomy is one of them. Due to an increasing number of reported cases of maxillary central incisors with different anatomy, it is imperative to consider anatomical variations even in the most routine cases.

Comparison of the Efficacy of NeoNiTi, ProTaper, and Reciproc Files in the Retreatment of Curved Root Canals: a CBCT Assessment

Objective

Effective tools and methods are applied during root canal retreatment to eliminate root canal obturation materials and preserve the initial root canal anatomy. The present study compared the efficacy of Reciproc, Neoniti, ProTaper, and Hedstrom files in the retreatment of curved root canals.

Material and methods

In the present in vitro study, 100 root canals with 25‒45º curvatures were used. After the samples were initially prepared and examined by CBCT, the root canals were obturated with gutta-percha and randomly assigned to four groups (n=25). A retreatment was carried out in each group with NeoNiTi, ProTaper, Reciproc, and Hedstrom files. CBCT examinations were carried out again under the same conditions. The samples were evaluated at 3-, 6-, and 9-mm distances from the apex on the first and the second CBCT image for root canal transportation and remaining gutta-percha in the root canals. The time required for retreating each canal in each sample was recorded. One-way ANOVA and corresponding non-parametric tests were applied for data analysis.

Results

The root canal transportation in the NeoNiTi group was lower than that in the other groups and significantly different from the ProTaper group (P<0.05). There was a remaining gutta-percha after retreatments in all the four groups, which was not statistically significant (P>0.05).

Conclusion

Despite the fact that the NeoNiTi file produced less transportation than other file systems evaluated in the retreatment of curved root canals, all the files were very effective at the clinically acceptable levels.

Historical Perspectives on the Evolution of Root Canal Sealer/Cements

Various forms of sealing cements have been used in root canal procedures since the mid-1800s to create an impervious seal of the root canal system. In the process both entrepreneurs and charlatans have risen to the challenge. During the first half of the 20^th century, significant activity in this realm was realized, which set the standards for the evolution of contemporary materials and applications.

Corrosion resistance assessment of nickel-titanium endodontic files with and without heat treatment

Objectives

The aim of this study was to evaluate the corrosion resistance of heat-treated (Reciproc and WaveOne) and non-heat-treated (ProTaper and Mtwo) superelastic nickel-titanium endodontic files when immersed in a 5.25% sodium hypochlorite solution.

Materials and Methods

Anodic polarization curves were obtained with potential sweeps that began at the open circuit potential or corrosion potential (E_corr). The pitting potential (E_pit) was identified on the anodic polarization curve as the potential at which a sudden increase in current was observed. The micromorphology of the 28 tested files was analyzed before and after the electrochemical assay using scanning electron microscope (SEM). The data were analyzed using 1-way analysis of variance with the post hoc Bonferroni test (for E_corr) and the Student t-test for independent samples (for E_pit).

Results

The mean E_corr values were 0.506 V for ProTaper, 0.348 V for Mtwo, 0.542 V for Reciproc, and 0.321 V for WaveOne files. Only WaveOne and Protaper files exhibited pitting corrosion, with E_pit values of 0.879 V and 0.904 V, respectively. On the SEM images of the ProTaper and WaveOne files, cavities suggestive of pitting corrosion were detected.

Conclusions

Signs of corrosion were observed in both heat-treated and non-heat-treated files. Of the evaluated files, WaveOne (a heat-treated file) and ProTaper (a non-heat-treated file) exhibited the lowest corrosion resistance.

Mandibular First Molar with Six Canals: Case Report of Radix Entomolaris and Middle Mesial Canal

The purpose of this article is to report a successful endodontic treatment of a mandibular first molar with six canals; three root canals in the mesial root, two root canals in the distal root, and one radix entomolaris. The incidence of two anatomical variations presented in this report, middle mesial canal and radix entomolaris, is generally low. Knowledge of the internal anatomy of the root canals and their possible variations, and use of magnification, such as the operating microscope or loupes, can increase the chances of finding additional canals, contributing to the success of endodontic treatment.

Difference between the Actual and Labeled Concentrations of Several Domestic Brands of Sodium Hypochlorite

Introduction

Sodium hypochlorite (NaOCl) is extensively used in root canal treatment and its efficacy depends on the concentration of free available chlorine (FAC). This study aimed to assess the chlorine content of 10 domestically manufactured household bleach products available in the Iranian market and evaluate the effect of temperature, time and daily bottle uncapping on FAC concentration and pH of these products.

Methods and Materials

One-liter bottles of 10 available brands of household bleach (n=4 of each brand) were collected and randomly divided into four groups (n=10). Two groups were refrigerated at 4^°C while the remaining two were stored at room temperature. One group of refrigerated and one group of room temperature samples were subjected to daily bottle uncapping followed by agitation and recapping for 3 months (six times a week to simulate weekly office work). The remaining bottles remained untouched and served as controls. The concentration of FAC in each sample was measured using the iodometric titration assay, and the pH was measured using a calibrated pH-meter at baseline and 1, 2 and 3 months. The results were analyzed using the one-way ANOVA and t-test.

Results

The mean concentration of FAC in the solutions was 4.87±0.19% at baseline. The measured concentration of sodium hypochlorite was different from the labeled value. The concentration of FAC decreased over time in all samples; the greatest reduction occurred in room temperature samples subjected to daily uncapping while the smallest reduction occurred in refrigerated, capped bottles (19% and 1.9%, respectively). The pH of all products decreased over time. The mean reduction in pH was 1.1 for the samples stored at room temperature for 3 months and 0.8 for the refrigerated samples.

Conclusion

This in vitro study showed that the expected concentration of sodium hypochlorite solution made of household bleach for endodontic purposes is different from its actual concentration.

Endodontic Treatment of a Mandibular Second Premolar with Type XVII Sert and Bayirli's Canal Anatomy

For a successful root canal treatment, it is critical for the clinician to have a complete knowledge of the root canal morphology, interprets radiographs critically and properly assesses the pulp chamber floor. Anatomical variations are critical in diagnosis and a successful treatment outcome in endodontics. Knowledge of root canal morphology and anomalies is essential to succeed in root canal therapy. Mandibular premolars are famous for their atypical morphology. But the occurrence of type XVII Sert and Bayirli's root canal type is very rare in them. The purpose of this case report is to present treatment of a seldom root canal system in a mandibular second premolar. Reports of unusual cases cause clinicians to do an accurate clinical examination and radiographic interpretation and consider atypical root canal configurations.

Endodontic Treatment of a Maxillary Lateral Incisor with Two Canals: A Case Report

Variations in the number of roots and canals have been extensively reported in endodontic literature. One rare variation is presence of two separate root canals in maxillary lateral incisors. This study reports a maxillary lateral incisor with two canals. Although rare, knowledge about this anatomical variation can help in successful endodontic treatment of such teeth.

The Effect of Gaseous Ozone in Infected Root Canal

OBJECTIVES

During the treatment of chronic apical periodontitis and pulp necrosis the main role is to irrigate the root canal.

AIM

The aim of this in vivo study was to irrigate with 0.9% NaCl (Natrium Chloride), 2.5 % NaOCl (Sodium Hypochlorite Solution, Sigma Aldrich - Germany) and 2% CHX (Chlorhexidine Digluconate Solution, Sigma Aldrich - Spain) combined with Gaseous Ozone (Prozone WH, Austria).

MATERIAL AND METHODS

This study was realised in the University Dentistry Clinical Centre of Kosovo (UDCCK), respectively in the Department of Endodontic and Dental Pathology, Dental Branch, Faculty of Medicine, Prishtina, Kosovo. The 40 subjects involved in this study belonged to both genders, in age between 15 -65 years. The sample selection was randomised. The retroalveolar radiography for each patient was taken in the suspected tooth. As a therapeutic plan the authors decided to disinfect the root canal with the irrigants, as follows: 2.5 % NaOCl, 2 % CHX and gaseous ozone.

RESULTS

The statistical analyses were based on Kruskal - Vallis test, X - test, DF = 3, r < 0.01. In the isolated average number of the aerobe and anaerobe bacteria colonies, when gaseous ozone was used, there was the significant statistical difference.

CONCLUSIONS

When gaseous ozone was combined with irrigants 0.9%, 2.5 % NaOCl and 2% CHX, it was concluded that the number of colonies of aerobic and anaerobic bacteria was reduced.

Intra-manufacture Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometre

INTRODUCTION

Manufacturers offer gutta-percha (GP) cones matched with different sizes of endodontic files as an attempt to simplify the obturation process and create a tight seal in the canal. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different levels using laser micrometre.

METHODS AND MATERIALS

Twenty files and corresponding GP master cones of Reciproc R40 (40/0.06) (VDW, Munich, Germany), WaveOne Large(40/0.08)(Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo 40/0.06 (VDW, Munich, Germany) were examined using laser micrometre (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D₀, D₁, D₃ and D₆. The data was analysed using the independent t-test. The differences were considered at 0.05.

RESULTS

The diameter of GP master cones was significantly larger than that of the corresponding files at all levels in all brands. ProTaper GP diameter was closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, File=0.49).

CONCLUSION

Within the same manufacturer, GP cone diameters do not match the diameters of their corresponding files. Clinicians are advised to use a GP gauge to cut the tip so as to appropriate the diameter from a smaller sized GP cone.

Incidence of Dentinal Defects and Vertical Root Fractures after Endodontic Retreatment and Mechanical Cycling

Introduction:

The aim of this study was to evaluate the incidence of dentinal defects and vertical root fractures (VRFs) after endodontic retreatment and mechanical cycling (MC).

Methods and Materials:

Two hundred mandibular premolars were selected. Forty teeth were left unprepared (control group). The remaining 160 root canals were prepared with ProTaper instruments and filled by using two different techniques [eighty with lateral compaction (LC) and eighty with single-cone (SC)]. Forty canals from each group (LC and SC) received no further treatment. The remaining eighty teeth were divided into two groups (LCR and SCR) (n=40) in order to undergo the removal of the root filling, re-preparation and refilling with lateral compaction and single-cone, respectively. All of the teeth were subjected to MC (1000000 cycles, 130 N, 2.2 Hz and 37^°C). The roots were sectioned at 3, 6 and 9 mm from the apex and observed under 20× magnification. The defects were classified as: no defect, VRF and other defects. Statistical analysis was performed using the Fisher’s Exact test and the Chi-Squared tests (α=0.05).

Results:

MC alone did not promote any other defects or VRFs. Experimental groups presented higher dentinal defects than the control group (P=0.021). Retreatment groups did not present a higher amount of dentinal defects than the groups that were subjected to the first treatment (P>0.05).

Conclusion:

Endodontic treatment and retreatment, regardless of the filling technique and MC, did not influence the occurrence of dentinal defects or VRFs in the human premolars.

Efficacy of Enamel Matrix Derivative in Vital Pulp Therapy: A Review of Literature

Introduction:

Vital pulp therapy (VPT) aims to preserve the health and maintain life of the tooth pulp which has been compromised by caries, trauma or restorative procedures. Recently, enamel matrix derivative (EMD) has been introduced as a material for vital pulp therapy. The aim of this review is to critically analyze and summarize the available literature on EMD for VPT.

Methods and Materials:

Online databases (PubMED/MEDLINE, Google Scholar, ISI Web of Science, and Wiley-Online) were searched by using the following keywords in various combinations: Enamel Matrix Derivative, Emdogain, ‘Vital Pulp Therapy, ‘Apexogenisis’, Apexification, Pulp Capping, Endodontics, Dentine and Pulpotomy for studies indexed from January 1949 to April 2016. We used an English-limited search in Google.co.uk for the missing grey literature. All studies fulfilling the selection criteria were carefully reviewed for the focused question: “Does using EMD in VPT, compared with other materials, result in better clinical, radiographic and histological outcomes?”.

Results:

The primary search resulted in 18 articles of which, 14 articles (including 6 animal studies and 6 clinical trials and 2 case reports) met the inclusion criteria for this review and hence were included. The number of teeth tested in the animal studies ranged from 8 to 144 including pigs, rats and dogs teeth. A number of studies used EMD in the experimental group in comparison with calcium hydroxide, propylene glycol alginate (PGA) and MTA as a control. The observation period ranged from 1 to 2 months and 4 out of 6 animal trials reported more favorable outcomes with EMD while two studies reported comparable outcomes.

Conclusion:

Although EMD has potential for various applications in endodontics, studies conducted to date have failed to demonstrate any significant advantage of EMD over conventional VPT materials. Additionally, the 5-year and 10-year survival rate of EMD-treated teeth is not yet known. Hence, studies with a longer follow-up periods are required to deduce the long-term viability of teeth treated with EMD.

Evaluation of Capacity of Essential Oils in Dissolving ProTaper Universal Gutta-Percha points

PURPOSE

Solvents may be used to remove the filling materials. The purpose of this in vitro study was to evaluate and compare the efficacy of formulated orange oil, orange oil and formulated eucalyptol in dissolving F3 ProTaper Universal Gutta-percha points.

MATERIAL AND METHODS

200 samples were used and divided into four groups, further divided in fifty samples for each solvent. The samples were weighed on an analytical balance before being subjected to the action of solvents. Subsequently, they were put onto watch glasses, 7X45mm in length, and immersed into solutions for the following times: 5, 10, 20, 25 and 30 minutes. The loss of mass was recorded by weighing samples after every minute of action of the solvent on the points. Data were statistically analyzed by Kruskal-Wallis test at a significance level of 5%.

RESULTS

All solvents showed that the first five minutes of action was the period of greatest dissolving power. In terms of immersion time, xylol (control group) exhibited a markedly superior ability in dissolving the gutta-percha points compared to other solvents and, also, showed statistically significant differences. A continuous dissolution was observed in all groups. Formulated orange oil presented a markedly superior solvent effect on filling materials compared to orange oil and formulated eucalyptol; however, there were no statistically significant differences.

CONCLUSION

Considering the results obtained and methodology employed, it can be concluded that xylol was the most effective solvent in dissolving gutta-percha points, followed by formulated orange oil, orange oil and formulated eucalyptol oil.

Root Canal Morphology of Permanent Mandibular Premolars in Iranian Population: A Systematic Review

INTRODUCTION

It is essential for clinicians to have knowledge about root canal configuration, although its morphology varies largely in different ethnicities and even in different individuals within the same ethnic group. The current study reviewed the root canal configuration of root canals in mandibular first and second premolars among Iranian population based on independent epidemiological studies.

METHODS AND MATERIALS

A comprehensive search was conducted on retrieved articles related to root canal configuration and prevalence of each types of root canal in mandibular premolars based on Vertucci's classification. An electronic search was conducted in Medline, Scopus and Google Scholar from January 1984 to September 2015.

RESULTS

In eleven studies conducted in eight provinces, 1644 mandibular first premolars and 1268 second premolars were investigated. Within mandibular first premolars, 70.9% were Vertucci's type I, followed by 10.4% type III, 7.18% type IV, 5.23% type II and 5.16% type V. In addition, among mandibular second premolars, 82.86% were type I, 6.25 type III, 5.32% type II, 4.27% type IV, and 0.69% type V.

CONCLUSION

These results highlight the necessity of searching for additional possible root canals by clinicians. Moreover, these results indicated the ethnical characteristics of Iranian population regarding the morphology of mandibular premolars compared to other populations.

Comparison of Antibacterial Effects of 810 and 980- nanometer Diode Lasers on Enterococcus Faecalis in the Root Canal System -An in vitro study

Background and aim: Use of laser technology in endodontics has greatly increased in the recent years due to the introduction of new wavelengths and methods and optimal antimicrobial and smear layer removal properties of lasers. This in vitro study aimed to compare the antibacterial effects of diode lasers of 810 nm and 980 nm wavelength on Enterococcus faecalis (E. faecalis) biofilm in the root canal system. Materials and methods: Fifty single-canal human anterior teeth were cleaned, shaped, sterilized and randomly divided into four groups namely two experimental, one positive and one negative control group. The experimental and positive control groups were inoculated with E. faecalis and incubated for two weeks. The experimental group one (n=20) received 810 nm diode laser irradiation (1.5W) while the experimental group two (n=20) was subjected to 980 nm diode laser irradiation (1.5W). The E. faecalis colony forming units (CFUs) were counted in each root canal before and after laser irradiation. Results: Laser irradiation significantly decreased the bacterial colony count in both experimental groups. The reduction in microbial count was significantly greater in 810 nm laser group compared to 980 nm laser group. Conclusion: Irradiation of both 810 and 980 nm lasers significantly decreased the E. faecalis count in the root canal system; 810 nm laser was more effective in decreasing the intracanal microbial load.

A Digital Stereomicroscopic Study of the Radicular Wall Thickness of Two-Canal Mandibular Incisors

OBJECTIVES

This study aimed to assess the radicular wall thickness in mandibular incisors with two canals and find the maximum and minimum thickness to prevent root canal treatment (RCT) procedural errors.

MATERIALS AND METHODS

A total of 160 extracted mandibular incisors were selected and radiographed; out of which, 55 had two canals. Three parallel transverse sections were made in each tooth at 1mm below the cementoenamel junction (CEJ), mid-root and 1 millimeter to the apex. Specimens were evaluated under a stereomicroscope and the thickness of radicular walls in each section was determined for the buccal, lingual and proximal surfaces. Data were statistically analyzed using Pearson's correlation coefficient test.

RESULTS

The thickness of radicular wall decreased from the cervical towards the apex. In all three sections (cervical, mid-root and apical), the thickness of lingual wall was significantly greater than the buccal wall. Also, the thickness of buccal and lingual walls was significantly higher than that of the proximal walls.

CONCLUSION

The lingual radicular wall had the highest thickness in two-canal mandibular incisors. Therefore, in these teeth, the lingual canal is a better choice for post placement.

Management of pulp canal obliteration using the Modified-Tip instrument technique

The incidence of pulp canal obliteration following dental trauma has been reported to be approximately 4 - 24% and its management can be quite challenging for the practitioner. Locating the canal and negotiating it to full working length may lead to iatrogenic errors such as fractured instrument and perforation. This case report deals with such a case using the modified tip instrument technique to gain access and negotiate the canal to the apex followed by conventional root canal preparation and obturation.

Antibacterial Efficacy of Aqueous Ozone in Root Canals Infected by Enterococcus faecalis

BACKGROUND

In endodontics, the elimination of resistant bacteria such as Enterococcus faecalis plays an important role for treatment success in root canals. Therefore, new alternative irrigants (instead of sodium hypochlorite) have been researched to achieve ideal endodontic treatment.

OBJECTIVES

The aim of the present study was to evaluate and to compare the antibacterial effect of aqueous ozone with different concentrations and techniques of application (manual and ultrasonic) against E. faecalis in human root canals.

PATIENTS AND METHODS

Eighty single-root mandibular premolar teeth were selected, prepared and sterilized. E. faecalis was incubated in the root canals and kept at 37°C for 24 h. The teeth were divided into four main groups each has 20 members: NaOCl (positive control) group; 8 ppm aqueous ozone group; 12 ppm aqueous ozone group; and 16 ppm aqueous ozone group. While half of the specimens were disinfected with aqueous ozone by manual technique, the other half was disinfected with the aqueous ozone by ultrasonic technique. Conventional irrigation technique was simultaneously applied with ultrasonic vibration that was produced by VDW.ULTRA device. The disinfection procedures were performed for 180 s to ensure standardization of all the working groups. Paper points (placed in the root canals before and after the disinfection procedures) were transferred to Eppendorf tubes containing 0.5 mL of brain heart infusion broth. Then, 50 μL of the suspension was inoculated onto broth agar media. Microbial colonies were counted, and the data were evaluated statistically using 2-way analysis of variance (ANOVA) and Tukey tests.

RESULTS

Although the antibacterial effect of 16 ppm aqueous ozone using a manual technique had an insufficient effect, its ultrasonic application technique resulted in complete disinfection in the root canals.

CONCLUSIONS

The bactericidal activity of high concentration of aqueous ozone combined with ultrasonic application technique showed efficacy similar to that of 5.25% NaOCl in root canals.

Push-Out Bond Strength of Dorifill, Epiphany and MTA-Fillapex Sealers to Root Canal Dentin with and without Smear Layer

INTRODUCTION

The aim of the present experimental study was to evaluate the push-out bond strength of Dorifill, Epiphany and MTA-Fillapex sealers to root canal dentin in presence and absence of smear layer (SL).

METHODS AND MATERIALS

Sixty human single-rooted teeth were selected and divided into six groups (n=10). The canal irrigation protocol in groups 1, 3 and 5 consisted of 2.5% NaOCl during instrumentation and normal saline at the end of preparation plus a 5-min irrigation with 17% ethylenediaminetetraacetic acid (EDTA). In the remaining groups, normal saline was used for canal irrigation. The root canals were filled with Epiphany/Resilon (groups 1 and 2), Dorifill/gutta-percha (groups 3 and 4) and MTA-Fillapex/gutta-percha (groups 5 and 6). After two weeks of storage in 95% relative humidity at 37(º)C, 2 mm-thick dentin disks were prepared from coronal third of each root. The push-out bond strength test was carried out using a universal testing machine. Data were analyzed with the two-way ANOVA and post hoc Tukey's tests. Statistical significance was defined at 0.05.

RESULTS

The highest (3.06±0.38 MPa) and lowest (1.16±0.32 MPa) push-out bond strength values were recorded in Epiphany/Resilon-NaOCl/EDTA and Dorifill/gutta-percha/normal saline groups, respectively. There were significant differences in the bond strength of sealers (P<0.05). In addition, elimination of the SL significantly increased the bond strength of all sealers (P<0.05).

CONCLUSION

The Epiphany/Resilon group exhibited the highest push-out bond strength in the presence and absence of the SL. Elimination of the SL resulted in a significant increase in the bond strength of all the sealers to dentin.

Various strategies for pain-free root canal treatment

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.

An update on the management of endodontic biofilms using root canal irrigants and medicaments

Microbial biofilm is defined as a sessile multicellular microbial community characterized by cells that are firmly attached to a surface and enmeshed in a self-produced matrix of extracellular polymeric substances. Biofilms play a very important role in pulp and periradicular pathosis. The aim of this article was to review the role of endodontic biofilms and the effects of root canal irrigants, medicaments as well as lasers on biofilms A Medline search was performed on the English articles published from 1982 to 2013 and was limited to papers published in English. The searched keywords were "Biofilms AND endodontics", "Biofilms AND sodium hypochlorite", "Biofilms AND chlorhexidine", "Biofilms AND MTAD", "Biofilms AND calcium hydroxide", "Biofilms AND ozone", "Biofilms AND lasers" and "Biofilms AND nanoparticles". The reference list of each article was manually searched to find other suitable sources of information.

Shaping ability of nickel-titanium rotary instruments in curved root canals

INTRODUCTION

Disinfection and subsequent obturation of the root canal space require adequate mechanical enlargement of the canals. The purpose of this in vitro study was to compare the shaping ability of Mtwo, RaCe and Medin rotary instruments during the preparation of curved root canals.

MATERIALS AND METHODS

Sixty mesiobuccal root canals of mandibular molars with severe curvatures between 25-35(°) and radius of 4-9 mm were randomly divided into three groups of 20 canals each. Using pre- and post-instrumentation radiographs, straightening of the canal and the apical transportation were determined with AutoCAD software. The data were analyzed using Chi square, analysis of variance, and post-hoc tests and the significance level was set at P<0.05.

RESULTS

Mtwo instruments maintained the canal curvature significantly better than Race and Medin instruments (P<0.05). There was significant difference between the rotary instruments for iatrogenic transportation of the major foramen (P>0.05).

CONCLUSIONS

Under the conditions of this in vitro study, Mtwo instruments seemed superior to the two other rotary instruments.

Management of single-rooted maxillary central incisor with two canals: a case report

The aim of this study was to report the endodontic management of right maxillary central incisor having two canals with type IV Vertucci canal configuration. Internal morphology of root canals is variable and often complex. Therefore, to achieve a technically satisfactory endodontic outcome, the clinician must have adequate knowledge of the internal canal morphology and its variations in order to debride and obturate the root canal system thoroughly.

Mandibular first premolar with three roots: a case report

Anatomy of the root canal system always effects endodontic treatment outcome. Mandibular premolar teeth show extreme variations in root canal morphology. First premolars usually exhibit basic one root and one canal anatomy. The occurrence of three roots in mandibular first premolar has not been commonly reported in literature. This article reports a case of successful nonsurgical endodontic management of mandibular first premolar with three canals and three different apical foramina.

Propolis: a new alternative for root canal disinfection

INTRODUCTION

This study evaluated and compared colony forming units (CFUs) and minimum inhibitory concentrations (MICs) of calcium hydroxide and propolis as intracanal medicaments.

MATERIALS AND METHODS

Eighty human single-root and caries-free teeth were selected and divided into five groups. Crowns were removed. Root canals were then prepared in a step-back manner. The samples were then inoculated by Enterococcus (E.) faecalis and incubated for 21 days. Intracanal medications were applied including, calcium hydroxide (n=20), propolis (n=20), and ethanol (n=20). Two groups of 10 teeth were also used as the positive and negative controls. Microbiological sampling was performed utilizing a piezo-reamer drill after one week of incubation. The samples were plated and CFUs were counted after 48 hours. MICs of calcium hydroxide and propolis were measured by serial dilution and agar dilution methods, respectively. The statistical tests of ANOVA and Duncan post-hoc were used to compare different medications.

RESULTS

MICs and CFUs of propolis were dramatically less than calcium hydroxide. The difference between the groups was statistically significant (P<0.001).

CONCLUSION

Our results reveal that propolis is an effective antimicrobial intracanal agent.

Root canal treatment of maxillary and mandibular three-rooted premolars: case reports

Familiarity with the normal and abnormal anatomy of the root canal system is essential for successful root canal treatment. The possibility of concomitant three-rooted and three- canalled maxillary and mandibular premolars are extremely rare. The purpose of this paper was to report a case with a three-rooted maxillary first premolar and two three-rooted mandibular premolars.

Direct digital radiography versus conventional radiography for estimation of canal length in curved canals

Purpose

The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars.

Materials and Methods

Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-15°, 15-30°, >30°). After the placement of a 15 K-file, radiographs were taken with a conventional film (F-speed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence.

Results

There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves.

Conclusion

The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.

Evaluation of the Doxycycline Release from AH26 Sealer-Doxycycline Combination: An ex vivo Study

INTRODUCTION

The purpose of this ex vivo study was to determine the releasing characteristics and doxycycline dentinal diffusion of AH26 sealer-doxycycline combination from apical 3mm of tooth root and apical foramen.

MATERIALS AND METHODS

One-hundred and two recently extracted single-rooted human teeth were decoronated and prepared with #3 and #4 Gates-Glidden drills and rotary Mtwo files. Smear layer was removed; all surfaces except for apical 3mm of each root were sealed with two coats of nail polish. To quantify the release and diffusion of the doxycycline at different time intervals (30 min, 48 and 72 h) after root canal obturation, the samples were randomly divided into three groups (n=30; 0.5 h, 48 h, 72 h). To evaluate the release of doxycycline from AH26 sealer-doxycycline combination at six concentrations of antibiotic including 0.5%, 1%, 2%, 5%, 10% and 20%; each experimental group was divided into six equal subgroups (n=5). Root canals were filled with gutta-percha and AH26-doxycycline combinations and then were placed in vials containing 1.25mL of phosphate buffer saline solution (PBS). After 30 min, 48 and 72 h, the amount of doxycycline released from specimens into PBS were determined by measuring the absorbance values using UV spectrophotometry at λ(max)=350 nm. Data were analyzed using two-way ANOVA.

RESULTS

The findings of this study revealed that AH26 sealer-doxycycline combination released variable measures of antibiotic at each time interval and in the various concentrations. At 30 min, no statistically significant differences were obtained between the results of subgroups, but at 48 and 72 h these differences were significant (P<0.001). The results also showed that differences between 0.5 h, 48 h and 72 h were significant within subgroups (P<0.01).

CONCLUSION

Under the conditions of this ex vivo study, doxycycline can be released from AH26 sealer-antibiotic combination through 3mm of apical root and apical foramen at 30 min, 48 and 72 h after mixing the sealer with doxycycline at concentrations of 0.5% up to 20%.

Nonsurgical endodontic treatment of a maxillary central incisor with two separate roots: a case report

The success of endodontic therapy requires knowledge of the internal and external dental anatomy and its variations in presentation. This case report involves endodontic treatment of a traumatized maxillary central incisor with two separate roots.

A comparative study on the shaping ability of k3, profile and protaper instruments in simulated curved root canals

INTRODUCTION

The objective of this study was to compare the shaping ability of three rotary filing systems; constant taper K3 instruments, constant taper ProFile instruments and progressive taper ProTaper rotary instruments in clear resin blocks with simulated curved root canals.

MATERIALS AND METHODS

Forty five resin blocks were divided into three groups. Group A preparation was conducted with K3, Group B with ProFile and Group C with ProTaper instruments. Pre and post instrumentation images were superimposed and assessment of the canal shape was completed with a computer image analysis program at 14 levels of the root canal system.

RESULTS

Group A inner and outer curvature pre and post instrumentation values were significantly different (P<0.05) at levels 3; at level 13 only the outer curvature and levels 6, 7, 8 the inner curvature had significantly different values between pre and post instrumentation. Group C had significant P values (P<0.05) at levels 2, 3, 4, 12, 13 in the outer curvature and at levels 6, 7, 8 of the inner curvature.

CONCLUSION

Overall, all three rotary instruments maintained root canal curvatures well. ProTaper instruments significantly removed more resin material from outer canal curvature in the apical third when compared to the other two groups.

An In Vitro Study of the Number of Distal Roots and Canals in mandibular First Molars in Iranian Population

INTRODUCTION

The purpose of this study was to evaluate the number of distal roots and canals in mandibular first molars and their internal anatomy radiographically within Iranian population.

MATERIALS AND METHODS

A total of 310 distal roots of mandibular first molars were incorporated in this study and evaluated in terms of number of roots and number and types of canals. Root canal systems were studied in vitro by means of radiography and based on Vertucci's classifications.

RESULTS

It was shown that 4.5% of the teeth in this study had two distal roots, of which, 100% indicated type I for both distobuccal and distolingual roots. Among all the teeth, 43.2% had two canals, 24.2% two apical foramina, and 38.7% two orifices in their distal roots. According to Vertucci's classification 54.9% of the teeth were type I, 19% type II, 1.9% type III, 14.2% type IV, 4.2% type V, 1% type VI, 0.3% type VII and 0% type VIII.

CONCLUSION

In as many as 43.2% of all teeth assessed in this study, bicanaled distal roots were observed, dentists are always recommended to search for the second canal in distal roots of mandibular first molars. In case the second canal in the distal root is missed, failure of endodontic treatment will be anticipated. A rectangular type access cavity design allows better visualization and negotiation of the probable second canals within the distal roots of mandibular first molars.