Journal of Dental Medicine

Background and Aim: Several materials have been introduced for retrograde fillings, pulp capping and sealing root perforations, but their biological effect on vital tissues and cells is not clear. The purpose of this study was to evaluate the reaction of human periodontal ligament fibroblasts to four root canal filling materials: Pro Root MTA, Root MTA, Portland cement and amalgam.

Materials and Methods: In this experimental study, impacted or semi impacted third molar teeth were extracted in aseptic conditions and tissues around the roots were used to obtain fibroblast cell line. After proliferation, cells were cultured in chamber slides and extracts of materials were added to wells. Fibronectin, type I collagen and TGF-  expression were measured by immunocytochemistry method. Data were analyzed by SPSS 11.0 using one way ANOVA and Tukey test. P<0.05 was considered as the limit of significance.

Results: Collagen I expression was higher in Pro Root MTA group after 24 hours (p<0.05) and in Portland cement group and positive controls after 48  hours. Portland cement group showed the highest expression of collagen after 1 week. There was no significant difference in fibronectin expression after 24 hours. After 1 week the highest expression of fibronectin was seen in Portland cement, Root MTA and Pro Root MTA groups. TGF-  expression was higher in amalgam, Root MTA and Pro Root MTA specimens after 24 hours and was the highest in Pro Root MTA group after 48 hours.

Conclusion: Based on the results of this study, Portland cement and Root MTA are comparable with Pro Root MTA and better than amalgam regarding their effects on human periodontal ligament fibroblasts.

Background and Aim: Three Dimensional obturation of root canal is one of the main goals of root canal therapy to preserve health or reach the regeneration or healing of periapical tissues. Root end filling materials are used in numerous situations to reach the mentioned goals. One of the common root end- filling materials is mineral trioxide aggregate (MTA) which the foreign and Iranian ones are different in their prices. The aim of this study was to compare the rat connective tissue reaction to Iranian and foreign MTA.

Materials and Methods: This was an animal study in which 40 rats were divided into 5 groups of each 8. The polyethylene tubes filled with foreign (Pro Root MTA) and Iranian (Root MTA) white MTA and were implanted in subcutaneous connective tissue. Similarly, the empty tubes were inserted in subcutaneous connective tissue as control group. The samples were examined histologically after 7, 14, 30, 60 and 90 days and were scored as followings: 0, was characterized to samples without inflammatory cells without inflammatory reaction 1, for samples with less than 25 inflammatory cells mild inflammatory reaction. 2, for samples with 25 to 125 inflammatory cells moderate inflammatory reaction and 3, for ones with more than 125 inflammatory cells severe inflammatory reaction. The data were analyzed using Kruskal-Wallis test and p<0.05 was considered as the level of significance.

Results: In general, inflammatory reactions were reduced in all groups. Experimental groups had moderate to severe inflammation in the 7th day which had significant difference with the control group having mild to moderate inflammation (p=0.04). There was not any significant differences between experimental and control group in 14th, 30th, 60th and 90th days (p>0.05).

Conclusion: Based on the findings of this investigation, inflammatory subcutaneous connective tissue reaction to Iranian (Root MTA) and foreign (Pro Root MTA) MTA was the same.

Background and Aim: Elimination of microorganisms and their byproducts from root canal system is one of important aims of root canal therapy. This object is gained by using of many chemomechanical techniques but with noncertain success. A new method is used of nonpathogenic bacteria for growth inhibition of pathogenic bacteria, Antibiosis, in root canal therapy.The aim of this study was in vitro evaluation of antimicrobial effect of probiotics, such as Lactic Acid Bacteria (LAB) on the infected root canal bacteria.

Materials and Methods: Isolated bacteria from infected root canal were grown and then scattered onto the muller Hinton agar plates which contain wells, LAB, extracted from dairy products, were added into these wells, Inhibition effected of LAB was determined. Furthermore the sample taken from the inhibition zone and possible resistant monoclonal bacteria also were identified, then 6 sensitive and 14 resistant samples were selected and E. faecalis species were added to them Then antimicrobial effects of LAB on these samples was reevaluated.

Results: The results showed that 66.7% of the samples were sensitive at least to one type of LAB, and 33% were resistant to all kind of LAB. Meanwhile the outgrowing anaerobic bacteria inside the inhibition zone were from the low frequency oral bacterial flora. Furthermore, adding E. faecalis to the samples caused more sensitivity of them to LAB. Mc-Neamar test recognized the difference significant.

Conclusion: This study showed that the LAB inhibit growth of the pathogenic root canal bacteriae. Furthermore, presence of E. faecalis reinforces the antimicrobial effect of LAB. It seemed that LAB maybe have potential to use in endodontic practice for elimination of root canal infections.

Background and Aim: Several agents were used for pulpotomy in primary molars. Formocresol is the most common drug in this procedure. In some studies it has been shown that, this material has potential some side effects, so it is essential to find other alternatives. The aim of this study was to evaluate clinical and radiographic success rates of mineral trioxide aggregate and formocresol.

Materials and Methods: In this randomized clinical trial study, 70 carious primary teeth of 4 to 7-year-old children were pulpotomized, and remaining pulp was dressed with Root MTA and formocresol. The clinical and radiographic follow up evaluations were performed at 6, 12 months by a blind dentist. The data were analyzed by Fisher's exact test.

Results: At the end of 1-year follow-up period, in formocresol group sinus tract and tenderness to percussion were seen in 2 teeth, internal resorption was seen in 1 tooth, and furcation radiolucency was seen in 2 teeth. Clinical and radiographic signs of failure were not seen in any case of (Iranian) Root MTA group.

Conclusion: Based on the results of this study, Iranian MTA can be used for pulpotomy in primary molars.

Background and Aim: Several surgical approaches have been used to achieve root coverage. The Subepithelial Connective Tissue Graft (SCTG) procedure has been shown to be a predictable means to treat gingival recession. Semilunar Coronally Positioned Flap (SCPF) is a simple mucogingival surgery to cover the exposed root surface without harvesting the palatal connective tissue. The purpose of this study is to compare the outcome of gingival recession therapy using SCTG and SCPF.

Materials and Methods: Forty Miller class I buccal gingival recessions (≥2mm) were selected. Recessions were randomly assigned to receive either the SCPF or SCTG. Recession Height (RH), Recession Width (RW), Width of Keratinized Tissue (WKT), Probing Depth (PD), Clinical Attachment Level (CAL), were measured at baseline, 1, 3, and 6 months after surgery. The data were analyzed using independent t-test and Repeated Measure ANOVA.

Results: The average percentages of root coverage for SCPF and SCTG were 88% and 71%, respectively and the complete root coverage observed were 55% and 45%, respectively. There were no significance differences between the two groups with regard to RW, PD, CAL, WKT (except in the third month after surgery which was slightly greater in SCPF group). RH was significantly decreased from 2 to 6 months after surgery in SCPF group.

Conclusion: The findings from this study indicate that if the tissue thickness and initial width of keratinized tissue are sufficient, SCPF may be a good substitute for SCTG in treatment of Miller class I gingival recessions.

Background and Aims: Considering advantages and disadvantages of mineral trioxide aggregate (MTA), Calcium Enriched Mixture (CEM) cement has been developed recently. The purpose of this study was to compare the apical microleakage of the root-end cavities prepared by ultrasonic or Er,Cr:YSGG laser and filled with MTA or CEM cement.

Materials and Methods: Eighty single-rooted, extracted human teeth were instrumented and obturated. Root-end resection was made by removing 3 mm of the apex. The teeth were randomly divided into two experimental (n=30) and two positive and negative control (n=10) groups. After that, the retrograde cavities were prepared using ultrasonic or Er,Cr: YSGG Laser. According to the root-end filling materials (MTA or CEM cement), each group was then divided into two subgroups. Finally, specimens were cleared for assessing the amount of apical dye (Indian ink) penetration. The data were analyzed using Kruskall-Wallis and Dunn tests.

Results: Laser/CEM cement group showed significantly the lowest mean apical dye penetration. There were no statistically significant differences between Laser/MTA, ultrasonic/MTA and ultrasonic/CEM cement groups.

Conclusion: Based on the findings of this study, CEM cement demonstrated lower rate of apical leakage compared with MTA, when the root-end cavities prepared with Er,Cr:YSGG Laser. The sealing ability of MTA was not different following root-end preparation by ultrasonic or Er,Cr:YSGG Laser.

 The goal of each root canal therapy is cleaning and obturating the entire root canal system. A thorough knowledge of root and root canal morphology and a good anticipation of their possible morphologic variations are essential and will help to reduce endodontic failure caused by incomplete root canal preparation and obturation. In this study, one case of maxillary molar with two palatal roots has been reported in a a 40-year-old woman is reported..

Background and Aims: Nowadays, calcium hydroxide is used as a dressing for canal sterilization and repair progression of apical lesions. The aim of this study was to investigate the effect of calcium hydroxide as an intracanal medicament on the apical microleakage of root filling.
Materials and Methods: In this experimental study, 46 extracted single-rooted human teeth were instrumented with step-back technique to master apical file (MAF) size 35. Specimens were randomly divided into 2 groups (n = 20). In group 1, the specimens were treated with calcium hydroxide intracanal medication and in group 2, the samples did not receive any medication. The teeth were incubated in 100% humidity at 37°C for one week. After that, calcium hydroxide was removed using irrigation with normal saline and reaming with MAF. The root canals were obturated with gutta- percha and AH26 sealer using lateral compaction technique. Specimens were incubated in 100% humility at 37°C for 72 hours and then immersed in India ink for 1 week. Finally, the teeth were cleared and the maximum linear dye penetration was measured under a stereomicroscope at 4X magnification. The data were analyzed by T-test and Chi-square.
Results: There was no significant difference between the two experimental groups (P=0.068).
Conclusion: The findings of this study indicated that using calcium hydroxide as an intracanal medicament did not influence the apical microleakage after final obturation of the root canal system.

Background and Aims: The seal provided by a root canal filling may be compromised by post space preparation. The aim of this study was to compare coronal microleakage around cast posts and prefabricated pins.

Materials and Methods: Thirty-eight extracted single-rooted, maxillary human teeth were prepared with step back method and filled with gutta-percha and sealer. After removing 8 mm of coronal gutta-percha with peeso-reamer drills #2 in twenty canals, the teeth were divided into three groups: cast post & core, prefabricated pin,  and gutta-percha (without any post or pin). After thermocycling, the samples were immersed in India ink for seven days. Finally, the specimens were cleared and the coronal microleakage of dye was then measured by the stereomicroscope. The data were analyzed by One-way ANOVA and Tukey HSD tests.

Results: According to the results, the mean dye penetration in cast posts, pins, and group without post or pin was 3.3 (0.39), 5.2 (0.47), and 7.2 (0.15) mm, respectively. There was no statistically significant difference between the groups (P>0.05).

Conclusion: Considering the importance of adequate filling of crown for prevention of microleakage, the method for coronal filling must be selected with caution. According to the results of this study, no significant difference between microleakage of cast posts and prefabricated pins was observed.

Background and Aims: Working length determination and remaining this length is of great importance in root canal therapy. Recently, electronic apex locators are being used to determine working length and decrease the number of radiographs. The purpose of this study was to compare the sensitivity of Root ZX and Novapex electronic apex locators with radiography in a clinical study.

Materials and Methods: In this study, 73 single-canalled teeth of the patients referred to the endodontic department of the Yazd Dental School were evaluated. The access cavity was prepared and working length of the root canals were measured by using the apex locators: Root ZX and Novapex. The file was placed in the root canal and a periapical radiograph was taken using parallel technique. The working lengths obtained by apex locators were recorded and compared with those of radiographs. The data were analyzed by Pearson's correlation coefficient, Wilcoxon test and paired t-test.

Results: The exact measurement without any fault was 46.6% for Root ZX and 20.5% for Novapex compared to radiography. In the range of 0.5 mm fault, the results were 91.8% for Root ZX and 64.4% for Novapex compared to radiographic measurements. The difference between the average of the measured lengths by Root ZX and radiography was not significant (P=0.17). On the other hand, the results showed significant difference between the average of the measured lengths by Novapex and radiography (P=0.017). The difference between two apex locators was not significant (P=0.061).

Conclusion: Root ZX and Novapex with high accuracy are useful for determining working length of the root canals in pregnant patients with special anatomic conditions and patients with muscle disharmony. Therefore, the use of these apex locators combined with radiography is recommended in root canal treatment.

Background and Aims: Apical root resorption is an adverse side effect of fixed orthodontic treatment which cannot be repaired. The aim of this study was to use panoramic radiographs to compare the root resorption before and after the orthodontic treatment with standard edgewise .018 appliance.

Materials and Methods: The before and after treatment panoramic views of sixty-three patients needed fixed orthodontic treatment included 1520 teeth were categorized into 3 Grades (G0: without resorption, G1: mild resorption with blunt roots or ≤ 1/4 of root length, G2: moderate to severe resorption or > 1/4 to 1/2 of root length. Relationship between root resorption and sex and treatment duration was analyzed with Mann-whitney and  Spearman's correlation coefficient, respectively.

Results: The findings showed that 345 teeth were categorized as Grade 1.  Grade 2 of root resorption was not found in this study. The highest amount of root resorption was recorded for the mandibular lateral incisor. In both gender, the root resorption of the mandible was more than that of the maxilla. The males showed significantly higher rate of resorption than the females (P<0.05). Root resorption was not significantly related to the treatment duration and the side of the jaws (P>0.05).

Conclusion: The mandible and male patients showed higher amount of root resorption. In addition, root resorption was not related to the treatment duration and the side of the jaws.

  Background and Aims: Successful root canal therapy requires knowledge of tooth anatomy and root canal morphology. For permanent mandibular premolars, great variety in size, shape and number of roots and root fusion expression has been reported in the literature. There is a wide variety of methods used in studies for evaluating the root canal morphology. One of these methods is Cone-beam Computed tomography (CBCT) that reduces the limitations of two-dimensional X-ray imaging, with less exposure in comparison with other 3D radiographies. Thus, this study was designed to evaluate the differences in the root and canal morphology of permanent mandibular premolars in an Iranian population by means of CBCT images.

  Materials and Methods: We searched a database of CBCT scans and evaluated 400 (20-60 years old) patients who met the inclusion criteria and teeth in this images (CBCT) were evaluated in three dimensions (Axial, Coronal and Sagital). Tooth length, number of roots, number of canals, canal type, root curvature and the effect of gender on any of the items mentioned were evaluated. Data were analyzed using T-test.

  Results: The average length of the first premolar of mandibular was 22.27 mm and second premolar was 22.28 mm. 98.4% of the first premolar and 98.2% of the second premolar were single root., and 87.3% and 93.1% were single channel. The incidence of number of canals based on vertochy divisions were:type 1: 90.7% and 90.8%, type 0: 2.2% and 2.8%, type 4: 3.3% and 3.1%, type 6: 1.4% and 2.1% and type 3: 2.5% and 1.5% respectively. In any case, there was no significant difference between males and females (P<0.001).

  Conclusion: Results indicate that dentists can obtain valuable information about the anatomy and morphology of the root canals using CBCT.

  Background and Aims: Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to root resorption of the adjacent tooth. The purpose of this study was to determine this resorption using panoramic and periapical radiographs.

  Materials and Methods: In this cross-sectional descriptive study 54 patient (28 men, 26 women) above 15 years old with the average of 22 years in Oral and Maxillofacial Department of Tehran University were studied. A periapical radiography from the third molar and a panoramic radiograph were taken from each patient (Because of their routine use and evaluation of accuracy of panoramic compared with periapical), and the magnitude of the root resorption for the second molar was determined by 2 observers and written in a questionnaire. Data were analyzed using Fisher test.

  Results: The prevalence of the root resorption of the second molar adjacent to the impacted third molar in the panoramic and the periapical radiographies, with respect to the limitation of the sample size were 46.3% and 31.5%, respectively, with 95% confidence(P>0.05). Most of these resorptions were in the cervical third of the second molar roots and in cases in which the third molars were mesially oriented or horizontal. There was also no significant difference between panoramic and periapical radiographs.

  Conclusion: Due to the increased risk of the resorption of the second molar adjacent to the third molar, extraction of the impacted third molars, especiall y mesially oriented or horizontal ones are recommended.

  Background and Aims: Root canal therapy is one of the most important parts of a general dentist's profession. The aim of this study was to evaluate the radiographic quality of root canal therapy performed by under graduated students at Yazd dental school.

  Materials and Methods: Records of patients, who were referred to the endodontic department during 2010-2012 and treated by undergraduated students, were divided into three groups by the numbers of canals and 80 specimens from each group were randomly evaluated. For the assessment, the quality of accomplished treatments, the indices: length, taper, and density of obturation were used and the errors during root treatment were recorded. Data were analyzed using Fisher's exact test and Chi-square.

  Results: According to the results, 155 (64.6%) records had appropriate filling length, whereas 55 (22.9%) were underfilled and 30 (12.5%) were overfilled. The acquired difference was statistically significant among three groups. (P<0.001). 187 (77.9%) records had adequate taper and 157 (65.4%) records had adequate density. The difference in the evaluating of taper (P=0.976) and density (P=0.879) was not significant. Totally, 39.2% of specimens had all the properties of an appropriate root canal treatment.

  Conclusion: The results of the present study can be used to identify weaknesses in the treatment of different educational groups and help them to achieve a proper planning to improve the quality of endodontic treatments.

  Background and Aims: Considering the complications of root canal system, debridement would not be effective only by mechanical instrumentation. Therefore, root canal irrigants with the antimicrobial effect that can eliminate more microorganisms during treatment, becomes important. The aim of this study was to compare the antimicrobial effects of 2% thyme essence, 2.5% sodium hypochlorite (NaClO), and normal saline as root canal irrigants for primary molar teeth.

  Materials and Methods: This study was performed on 34 primary molars. Subjects were randomly divided into three groups (N=10). The root canals of the teeth were prepared up to the file #35 and all of the specimens were sterilized, and were then contaminated with entrococccus faecalis suspension (Enterococcus Faecalis ATTC 29212). After 48 hours of incubation, the specimens of each group were irrigated with corresponding irrigants. Then, the microbial specimens were collected with sterile paper points. After incubation, the numbers of Colony Forming Units (CFU) were counted using colony counter. Data were analyzed using Smirnov-Kolmogorov, Kruskal-Wallis and Mann-Whitney tests.

  Results: Sodium hypochlorite showed the highest antimicrobial effect and showed significant differences compared with normal saline (P<0.001). However, the differences were not significant with thyme essence 2% (P=0.3).

  Conclusion: Thyme essence could be considered as a natural irrigator with a comparable antiseptic effect to sodium hypochlorite.

  Background and Aims: Postoperativee endodontic pain is an outstanding problem for dental patients. Therefore, a successful management of endodontic pain has become as one of the main dental objectives. The aim of the present study was to compare the postoperative endodontic pain in patients under general anesthesia versus local anesthesia.

  Materials and Methods: For conducting this clinical trial study, 50 patients having mandibular molars candidate for root canal therapy were selected. Twenty-five patients treated under general anesthesia because of their fear, anxiety or gag reflex. Other 25 patients treated under local anesthesia. All teeth were prepared using engine-driven rotary system in a crown-down technique and filled using lateral condensation technique. Heft- parker visual analog scale was used to measure the degree of pain at 6, 12, 24, and 48 hours after the treatment. Mann-Whitney, Chi-square, and T-tests were used to compare the intensity of postoperative pain between the groups.

  Results: The mean intensity of postoperative pain in local and general anesthesia groups at 6, 12 and 24 hours had statistically significant difference (P<0.05).

  Conclusion: Postoperative pain in patients who treated under general anesthesia was significantly less than the patients who treated under local anesthesia.