Iranian Endodontic Journal
Volume:6 Issue: 2, Spring 2011

Diseases of the dental pulp and periapical tissues are chiefly caused by microorganisms. Antibiotics are used in some endodontic cases; however, successful cases can predominantly be achieved by mechanical and chemical cleaning of the canal or surgical intervention. The aim of this study was to determine the knowledge of General Dental Practitioners (GDPs) in Shiraz in respect to antibiotic prescriptions during and after endodontic treatment. A one-page questionnaire was sent to 200 active general dentists. Of the 120 surveys returned, 93 were accepted. The data were analyzed using t-test, Chi-square, ANOVA and Fisher’s Exact Test. Only 29% of dentists had full knowledge (correct answers to all questions) of antibiotic prescription protocols in pulpal and periapical disease. Amoxicillin 500 mg capsule was the drug of choice of dentists. Total of 42% of GDPs had full knowledge of antibiotic prescription protocols for persistent or systemic infections cases. GDPs more recently qualified had slightly greater knowledge compared to GDPs with experience; however, this difference was not significant. Also, there was no significant difference between genders. General practitioners’ knowledge about antibiotics seems inadequate and further education is recommended to update the practitioners.

Blood contamination of the canal during preparation can be a major problem in endodontics; this may result in apical microleakage. The aim of this in vitro study was to evaluate the effect of blood on apical microleakage of a resin-based root canal sealer (AH26) and a polymer-based root canal sealer (Epiphany). In this experimental study, 50 decoronated central incisors and canine teeth were prepared by RaCe rotary system and randomly divided into 4 groups (n=10). Groups A1 and A2 were obturated by Epiphany/Resilon and AH26/Gutta-percha, respectively. The obturations were performed with a single cone technique after drying root canals. In B1 and B2 groups, the test groups, 0.02cc citrated human blood was injected into dried root canals and they were obturated in the same manner. Ten specimens were served as positive and negative controls (n=5).The apical leakage was measured by means of a computerized fluid filtration method after 1 day and 3 weeks. The data was analyzed by One-Sample Kolmogorov-Smirnov, Independent Sample t-test and univariate analysis. Statistical significances were preset at α=0.05. There was no significant difference in apical microleakage of the two sealers after 1 day and 3 weeks in dry and blood environment (P>0.05). Sealer and environment had no interaction (P>0.05). Blood contamination has no significant effect on the apical microleakage of Epiphny and AH26.

Determination of the working length by radiographic method has many drawbacks. Electronic apex locators have been developed to overcome some of these problems. Recently, a newly designed apex locator NovApex has been introduced. All the studies on the accuracy of NovApex have been carried out in vitro on extracted teeth which did not completely simulate the clinical situation. The aim of this study was to evaluate the accuracy of the NovApex in comparison with traditional radiographic method. Twenty-five patients whose lower molar was candidate for extraction were selected. The tooth was accessed, and the radiographic working length was determined by measuring the length of the initial file 0.5 mm short of the radiographic apex. Then, NovApex apex locator was used to measure the electronic working length. After that, the tooth was extracted, and the actual working length was measured by introducing a size 15 k-file into each canal until the file tip was visible at the apex and subtracting one half millimeter. Intraclass correlation coefficient and accuracy were calculated for assessing reliability. The accuracies were compared using Chi-square test. The accuracy of NovApex apex locator and radiographic method in detecting apical constriction within ± 0.5 mm was 74.7% and 68%, respectively which was significantly different

The aim of this in vitro study was to compare the efficacy of two retreatment rotary systems in removal of gutta-percha (GP) and sealer from the root canal walls with and without use of solvent. Sixty single-canalled distal roots of mandibular molars were prepared and root filled with gutta-percha and AH26. Each canal was randomly allocated to receive one of the retreatment techniques, Mtwo R or ProTaper. The groups were further divided into two subgroups: with or without the use of solvent. The cleanliness of canal walls was determined by stereomicroscope and scanning electron microscopy. The results showed that Mtwo R without the use of solvent was more efficient in material removal compared to ProTaper D

Rotary nickel-titanium (NiTi) instruments are thought to allow shaping of narrow, curved root canals more efficiently and more effectively than stainless steel hand instruments. However, the continued search for even more effective and safer instruments has resulted in new rotary systems being introduced on a regular basis. The aim of this study was to compare shaping parameters of RaCe and Mtwo NiTi rotary files with stainless steel K-Flexofile hand instrument. A total of 60 mandibular first molars with 20-40 degree of curvature in mesial root were divided in to three groups and each was prepared with one kind of instrument (RaCe, Mtwo, stainless steel K-Flexofile). Using pre and post-radiographs, canal curvature was measured, with the Schneider technique. Preparation time was recorded. For evaluating canal centering and transportation, the tooth was sectioned 3, 6 and 9 mm from the apex. Pre and postpreparation photographs were taken from mesiolingual canal. Data was statistically analyzed usingOne-way ANOVA and Chi-Square tests. RaCe and Mtwo maintained canal curvature better than K-Flexofile (P<0.001). Mtwo prepared the canal in a shorter time (P<0.001). Significant statistical difference was not found in the three canal sections between the various systems. RaCe resulted in significantly fewer canal aberrations and better centering ability.

This study investigated the fatigue and fracture modes of RaCe and ProTaper rotary instruments. Fatigue resistance was evaluated by rotating the files 30° or 60° and with 2 or 5mm radius of curvature. RaCe taper 06 size 25 and ProTaper F1 files (n=40) were used. The number of rotations to failure was analyzed by two-way ANOVA and independent sample t-test. Fracture surfaces were examined under a scanning electron microscope. Both files exhibited significantly more resistance to fracture when angle severity was reduced and increase in curvature radius (P=0.000). ProTaper demonstrated higher number of cycle of failure (P=0.0029) in one group (r=5mm, 60º). SEM observation revealed fatigue mark/features in 17 specimens, shear characteristics in 37 samples, and tensile overload in 26 samples. Radius of curvature was the main factor in torsional and fatigue. failures

Apexification with calcium hydroxide is associated with certain difficulties, such as requirement of longer treatment time, the possibility of tooth fracture and incomplete calcification of bridge. Use of mineral trioxide aggregate (MTA) is an alternative treatment for open apices because it is biocompatible, nonmutagenic, nonneurotoxic, can induces hard tissue formation and has good sealing properties. Here we report a case where MTA apical plug and anatomic post and core were used for reconstruction of maxillary central incisor. The patient was recalled after six months and no complications were noted. A periapical radiographs demonstrated that anatomical post and core remained well adapted to post space and complete healing of periapical lesion. This new technique is particularly advantageous in cases which have open apex, teeth whose root canals are not perfectly round, wide canals and thin radicular dentin and patients who want to complete the treatment in few visits, with each one as quick and easy as possible.

Inflammatory external root resorption (IERR) is a pathological phenomenon of microbial origin. This study reports a case of external apical inflammatory root resorption of maxillary incisors associated with periradicular lesions in a 22 year old female, which was successfully treated by one-visit root canal therapy (RCT). Radiographic investigation revealed periapical radiolucencies in the upper incisors associated with varying degrees of external inflammatory root resorption of teeth 12, 21 and 22. One-visit RCT of all involved teeth was carried out. Access cavities were permanently restored after 1 week. Clinical and radiographic examinations at 1 day, 1 week and 14 month follow-up demonstrated complete resolution of patient's signs/symptoms. The incisors were fully functional, and complete bone healing of the apical radiolucencies had taken place. The treatment outcomes demonstrated that IERR associated with periradicular lesions can respond successfully to one-visit RCT when conducted with adequate disinfection and a satisfactory coronal seal. Hence, one-visit RCT may be a good alternative to multiple-visit RCT involving intra-canal medicaments.