Journal of Dental Medicine

Background and Aim: Maintaining the original canal path and safety of canal preparation during instrumentation in curved canals have been subjected to many challenges. The aim of this study was to compare several parameters of root canal preparation using flexmaster rotary and hand used Nickel-Titanium instruments.

Materials and Methods: In this experimental study, sixty extracted human teeth with root canal curvatures between 10 and 42 degress were devided into two similar groups with equal mean curvatures. Root canals in one group were prepared using flexmaster rotary instruments and the other with NiTi hand files.After canal preparation, different parameters such as straightening of curved root canal, loss of working length, fracture rate, perforation and working time, were evaluated and compared between the two groups. Data were analyzed by t student test with p<0.05 as the limit of significance.

Results: Results showed that both instruments maintained the original canals' curvature. No loss of working length, instruments fracture or perforation was recorded. Working time was significantly shorter for flexmaster than hand files.

Conclusion: Both systems under investigation respected original root canal curvature and were safe to use. Therefore the rotary techniques could be successfully introduced to undergraduate endodontic programmes.

Background and Aim: Lead is one of the most dangerous metallic poisons which can lead to acute and chronic poisoning with a broad range of systemic and oral signs. The aim of this study was to evaluate the relationship between the prevalence of oral complications and blood lead level in workers employed in Koushk lead mines, Yazd province.

Materials and Methods: This analytical study was conducted on 70 subjects employed in Koushk lead mines and 70 workers in Yazdbaf textile factory as control group. A questionnaire including demographic information and medical questions was completed for each case and oral manifestations were recorded, as well. Blood samples were taken from subjects and blood lead level was measured by atomic absorption spectrophotometer. Data were analyzed using t, Chi-Square and Mann Whitney tests with p<0.05 as the limit of significance.

Results: The mean lead level was 7.06 µg/dl in case group and 4.97µg/dl in control group (P= 0.039). In case group, 3 subjects had blood lead level more than 20µg/dl. Statistical analysis showed significant differences regarding neurologic disorder, chronic fatigue, existence of lead line, mucous pigmentation, gingivitis, tongue burning, taste sense reduction and DMF between case and control groups (P<0.05).

Conclusion: Based on the results of this study, since the mean blood lead level in mine workers was in normal limits, the observed symptoms were not related to systemic poisoning. Direct contact of the oral mucosa with the lead in breathing air or other factors related to overall health problems in mine workers may be responsible for the present findings. Further studies are recommended on similar subjects working in different conditions.

Background and Aim: Incomplete root development caused by trauma ,caries, or pulpal pathosis requires special attention and treatment . Although calcium hydroxide apexification has been used successfully for years but it requires patient cooperation and multiple appointments . Single visit apexification with MTA has been used in recent years. The purpose of this study was to compare bacterial microleakage of two types of MTA (Made in Iran and Brazil) applied as apical barrier in open apex teeth.

Materials and Methods: 48 single root teeth were used in this experimental in vitro study. Teeth apices were prepared as open apex teeth. For canal obturation the 4mm of root end was filled with 2 types of MTA (white Iranian MTA salami co. Iran and Angelus MTA Angelus Brazil) from coronal access. Teeth were mounted in self-cured acryl and put in BHI microbial culture. A suspension of Staphylococcus epidermidis was injected from coronal area into the root canals.The teeth were incubated and examined every 24 hours for microbial microleakage, indicated as turbidity in culture. Data were analyzed using Fisher exact test with p<0.05 as the level of significance.

Results: Microleakage appeared after 15 days in all Iranian and after 17 days in Angelus MTA samples.There was no significant difference between microleakage of two types of MTA (P = 0.48).

Conclusion: Based on the results of this study, there was no significant difference between microleakage of Iranian and Angelus MTA. If further studies confirm other physical, chemical, biological and sealing properties of Iranian MTA, it could be recommended for clinical application

Background and Aim: Sealing the root canal system is of great importance in endodontic treatment especially in infected teeth. Several materials have been introduced for this purpose. The aim of the present study was to evaluate the sealing ability of MTA as an orthograde root filling material and compare it with laterally condensed gutta-percha with sealer.

Materials and Methods: Thirty-six extracted human maxillary central and canine teeth were used in this experimental study. After preparation and surface disinfection with 1% NaOCl solution, the crowns of the teeth were cut at cemento-enamel junction.Roots were randomly divided into four groups: two experimental groups  of 15 roots each (gutta-percha with AH26 sealer and MTA) and two control groups of 3 roots each (positive and negative). After root canal preparation and filling, the sealing ability of each technique was assessed by immersion in 1% methylene blue dye for 72 hours. Then the teeth were cleared and the extent of dye penetration was measured with a stereomicroscope. Data were analyzed by T-test with P<0.05 as the level of significance.

Results: The results showed that the mean microleakage was 1.1mm (SD=2.1) in the gutta percha group and 3.4mm (SD= 2.1) in the MTA group.This difference was statistically significant (P=0.013).

Conclusion: Based on the results of this study, canal obturation with gutta-percha and AH26 sealer may provide a better apical seal compared with MTA. However, further studies on microbial leakage are needed for more precise evaluation of the sealing ability of MTA.

Background and Aim: Extracted teeth used in preclinic should be disinfected. The aim of this study was to evaluate the effects of some disinfectants on microorganisms cultured from pulp chamber of extracted teeth.
Materials and Methods: In this experimental study 54 intact human teeth were collected. After access cavity preparation, 10 8 B. streothermophillus endospors were inoculated into pulp chamber. Then cavities were sealed with a temporary restorative material. Teeth were divided into 5 groups of 10 each. The teeth were then stored in these disinfectants: 5.25% hypochlorite sodium, 5% Microten, 5% Deconex, 2% Glutaraldehyd, and 10% Formalin for 48 hours. Two teeth were autoclaved as negative controls and two were stored in normal saline as positive controls. The teeth were then sectioned in cervical area and cultured in Trypticase Soy Broth. After three days turbidity in tubes was evaluated. Statistical analysis was done by Fisher's exact test.
Results: None of these solutions were able to prevent microorganism growth in all samples however, Formalin was better in six cases than that of other disinfectants. Differences between these five groups were not statistically significant (P=0.384).
Conclusion: Sterilization of the teeth with autoclave is the only absolute method for disinfecting the root canals of extracted teeth and disinfectants are not reliable for this purpose.

Background and Aims: Insolubility has been stated as one of the important characteristics of the materials which are used as sealers in the endodontic treatments. The aim of this study was to evaluate the solubility of four endodontic sealers (ZOE, Dorifill, AH26 and Tubliseal).

Materials and Methods: Five specimens from each sealer with similar size were prepared. After first weighing, the samples were stored individually in bottles containing 50 ml of distilled water at 37ºC. After 7 days, the specimens weighed and changes in the weight of each sample recorded with a digital scale. The data were analyzed by ANOVA and Post-hoc Tukey HSD tests.

Results: The results of this study indicated that Dorifill had the maximum solubility among all sealers with weight loss of 2.8%. Tubliseal and ZOE showed the weight loss of 1.4% and 2.3%, respectively. AH26 showed weight gain of 1.9% during 7 days. There were no significant differences in the mean weight changes between Dorifill, Tubliseal and ZOE groups (P>0.05). A significant difference was found between the mean weight changes of AH26 and that of the other groups (P=0.000).

Conclusion: From the results of this study, all tested sealers were in the standard limit of solubility, and thus, it could confirm this physical property of sealers for clinical applications.

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: Calcium hydroxide has a pronounced antimicrobial activity against most of the bacterial species found in infected root canals and endodontic infections. It is one of the most frequently used intracanal medications in endodontic therapy. The objective of this study was to determine the antimicrobial efficacy of six calcium hydroxide formulations (mixed with saline, lidocaine 2%, chlorhexidine 2%, chlorhexidine 0.2%, Iodine Potassium iodide (IKI) 2%, and glycerin) on Enterococcus faecalis using agar diffusion test.
Materials and Methods: Twelve culture plates were incubated with Enterococcus faecalis. Five cavities were made in each plate with 5 mm diameter and 4 mm depth. Two plates were randomly considered for each calcium hydroxide formulation and filled completely with creamy mixture of tested materials. The plates were incubated at 37ºC for 48 hours. The diameter of inhibition zone around each well was recorded in millimetres and data were submitted to ANOVA and Tukey tests.
Results: The results of this study showed that all tested calcium hydroxide pastes had good antimicrobial activity. The antimicrobial activity of calcium hydroxide mixed with lidocaine, chlorhexidine 2% and IKI 2% were significantly greater than that of calcium hydroxide mixed with saline (P<0.001). No significant differences in the antimicrobial  were found between the other groups (P>0.01).
Conclusion: Considering the results of this study, lidocaine 2%, chlorhexidine 2% and IKI 2% are suggested to be used for preparation of calcium hydroxide paste. Further studies with different methods are needed for confirming these results.

  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.