Iranian Endodontic Journal

INTRODUCTION: The effectiveness of low power lasers for incisional wound healing, because of conflicting results of previous research studies, is uncertain. Therefore, this study was carried out to evaluate low power laser effects on incisional wound healing. MATERIALS AND METHODS: Incisional wound was produced on thirty-six mature male guinea pigs under general and local anesthesia. In half of the cases, He-Ne laser radiations were used for five minutes and the rest were left untreated. Animals were divided into six groups of six animals each that were killed after 3, 5 and 14 days. After histopathology processing and H&E staining, specimens were examined for acute and chronic inflammations, epithelial cell migration, epithelial seal and barrier formation, fibroblast migration, fibrosis, clot formation and granulation tissue formation. Mann-Whitney U and the Wilcoxon tests were used for statistical analysis. RESULTS: Statistically significant differences were found between fibroblast migration, acute and chronic inflammation of radiated groups and the control group at 5 days interval (p<0.05). There was no statistically significant difference at 3 and 14 days between laser radiated and control groups. CONCLUSION: This study showed that He-Ne laser had beneficial effects on incisional wound healing particularly at 5 days interval; however, further research on chronic ulcers is recommended.

INTRODUCTION: Gutta-Percha, the concrete milky juice of the Sapotaceae family tree, is the most commonly used material for obturation of prepared canal space. Natural 1-4 trans stereochemical structure of Gutta-Percha is taken to a heating- inclusion process of various organic and inorganic elements by manufacturers. The purpose of this study is to detect the presence and percentage of inorganic filler elements and organic phase of various commercial brands and if the locally manufactured brand confonns to standard range of components. MATERIALS AND METHODS: Sample cones, size # 35, from Roeko, Hygienic, DiaDent and AriaDent brands were randomly selected. After burning out in the furnace, organic and inorganic phase percentage and presence of trace elements in each sample were detected and recorded using apparatuses such as SEM, XRF, TGA, IR, NMR, and Ion Chromatography.

RESULTS: With slight differences in polymer / filler ratio, 78% ± 2% for organic phase, no significant difference was recorded among these brands. SEM analysis detected Zinc, Barium, and Sulfur in Hygienic, DiaDent, and AriaDent in descending order; in the last two Silicones was also traced, while Zinc was the only element to be identified in Roeko. CONCLUSION: No significant chemical and structural differences among four commercial brands were detected.

INTRODUCTION: Clinical application of radiography in endodontic practice is affected by reproducibility in the orientation of the x-ray source, image receptor and object. The inability of dentists to locate intra oral films or sensors in appropriate positions in different cases can cause complications in the performance of endodontic therapy. Commercially available film holder (endoray) and conventional imaging methods seem to be insufficient and difficult to perform. The purpose of this investigation was to develop a novel and easily performed device for endodontic radiography and to asses its reproducibility and accuracy in vitro. MATERIALS AND METHODS: The present work surveys and evaluates the design steps of a newly constructed film holder with modified bite block and a beam guiding device, in an attempt to perform a diagnostic study. References wires and balls were attached on the film holder and to the alveolar crest of maxillary molar region inserted in the conventional phantom for measuring the projection errors relative to the film holder and repositioning .One hundred and twenty radiographs of a conventional phantom were taken by one of the authors and by two dental students using the novel device and Endoray. RESULTS: The %95 CI for precision of radiologist and one of the students was less than 8 (7.313 ± 0.1989) .The %95 CI for precision of the other student was less than 12 (10.941 ± 0.4217). There was no significant difference (p= 0.679), regarding the interoperator precision, between radiologist and first student. There was significant difference between second student and the others (p<0.05). No significant difference was noted between the radiographs achieved by the Endoray and new device. CONCLUSION: The novel device appears to be a potential means of obtaining reproducible radiographs in endodontic practice. Further research is needed however, to study in vivo aspects, reproducibility and accuracy.

INTRODUCTION: The purpose of this study was to evaluate the morphologic surface of gutta­percha cones after cutting with different methods. MATERIALS AND METHODS: The apical 3 millimeters of forty standardized, gutta-percha cones size 40 were cut off using scissors or a scalpel against a glass slab. The samples were then examined under scanning electron microscopy (SEM) for topographic deformity. RESULTS: According to results, cutting with scissors produced significant topographic deformity in the standardized gutta-percha cone surface but cutting with sharp surgical instrument against a glass slab allowed the development of a smooth and unmodified gutta­percha cone surface. CONCLUSION: Results of this study recommended that cutting the tip of a gutta­percha point with a sharp scalpel against a glass slab would produce more reasonable surface morphology than using scissor for the same procedure.

INTRODUCTION: Perforations of the pulpal floor create problems during endodontic treatment and often results in secondary periodontal involvement with eventual loss of teeth. The purpose of this study was to evaluate the ability of mineral trioxide aggregate (MTA), Amalgam, zinc oxide and eugenol (ZOE) and Portland cement to seal furcal perforations in extracted human molars using dye penetration. MATERIALS AND METHODS: This Microleakage study was conducted on 70 human permanent mandibular molars with well developed, non-fused roots. Access openings and furcation perforations were prepared in the pulp chamber floor. Ten teeth were assigned as controls and divided into two groups of five teeth each as positive and negative control. The positive group were accessed and perforated similar to experimental groups but the negative controls were not prepared. The rest of the teeth were divided in four experimental groups of 15 teeth in each group. Experimental groups comprised groups Al to A4, group Al was repaired with MTA, group A2 with Amalgam, group A3 with Coltozol (ZOE) and group A4 was repaired with Portland cement. The teeth were submerged in solution of 2% fucshin dye for 24 hours. Finally, the samples were sectioned and evaluated for linear dye leakage at X25 magnification and analyzed statistically. RESULTS: The results showed that MTA had significantly less leakage than Amalgam, Portland cement and Coltozol (P<0.05). CONCLUSION: Maximum dye penetration was observed in Coltozol followed in decreasing order by Portland cement and Amalgam.

INTRODUCTION: Prefabricated metal and ceramic posts can be used with different kinds of core materials as an alternative to the conventional casting post and cores. It is unclear how these post and core systems can withstand different kind of forces in the mouth. The purpose of this study was to compare the fracture strength of endodontically treated, crowned maxillary incisors restored with casting post and cores and glass- fiber post with composite core and to evaluate their mode of fractures. MATERIALS AND METHODS: Thirty caries free, human maxillary central incisors with incisoapical length of 23 ± 1 mm were divided into two groups. After root canal treatment procedures and decronation of teeth 2mm above cementoenamel junction, Grope 1 was restored with glass- fiber posts and composite cores and group 2 received casting post and cores. Teeth were prepared with a circumferential shoulder including a 1-2 mm ferrule and 0.5 mm bevel; all posts were cemented with an adhesive resin and teeth were restored with complete coverage crowns. Loads were applied at an angle of 135 degrees using a universal testing machine. Compression force was applied until the specimens fractured. RESULTS: The median fracture strengths of groups 1 and 2 were 459 and 686 respectively (p<0.05). In group I, all fractures occurred in incisal third of roots. In groups II, 40% of fractures were in apical third and middle of roots. CONCLUSION: Within the limitation of this study, the results suggested that glass fiber with composite cores can be used as an alternative to cast posts and cores in anterior teeth when creating 2mm ferrule effect was possible in normal occlusion. Clinical trial is required to verify these in vitro results.

INTRODUCTION: The purpose of the present study was to quantify and compare the amount of extruded debris from apical foramen after instrumentation of the root canal system with hand and rotary instruments. MATERIALS AND METHODS: Root canals of forty five fresh extracted single rooted human teeth with mature apexes and less than 15 degree of root curvature were instrumented in group A with stainless steel K-Type files, in group B with rotary NiTi Flex Master files, and in group C with rotary NiTi ProTaper files and followed weighting the extruded debris by a digital scale to within 0.0001 gram accuracy. RESULTS: In all groups, the mean weight of extruded debris was not more than 5 mg (P=0.0l) and was ranked as: Group A>Group B>Group C. There were statistically significant differences among three groups (p=0.0l). The mean value of extruded debris in the ProTaper and Flex Master groups were 0.652 and 0.788 mg, respectively. CONCLUSION: The study revealed that the amount of extruded debris from the apical foramen was minimal when ProTaper files were used.

INTRODUCTION: This article describes the diagnosis and treatment of two symmetrical maxillary first molars with two canals in their distobuccal roots. A 32-year-old female had an emergency treatment because of the pain in tooth #16. On the second visit after accessing the pulp chamber and detecting three major canals (MB, DB, and P) and exploring the 4th canal (MB₂), we noted that there was a 5^th canal in the distobuccal root. Also, necrosis was found in the same patient after examining the tooth #26 which was severely decayed. Then after preparing the access cavity, the same order of orifices was found in tooth #16. An electronic apex locator was utilized to ensure that a perforation of the pulpal floor had not occurred. Working films confirmed the presence of an additional canal in distobuccal root.