جستجوی مقالات مرتبط با کلیدواژه "نفوذ رنگ" در نشریات گروه "پزشکی"

Root canal obturation is an important step in endodontic therapy aiming at achieving a complete three-dimensional seal of the canal and preventing microleakage, reentry or growth of microorganisms in the root canal system. Several techniques and materials are available for root canal filling. Achieving an apical seal is among the most important characteristics of filling materials. This study aimed to compare apical microleakage of three different canal obturation techniques of Thermafil/Adseal, lateral condensation with gutta percha/Adseal and lateral condensation with Resilon/Epiphany using dye penetration method. This experimental study was conducted on 51 anterior single-rooted human teeth. The teeth were sterilized, the crowns were cut and canals were prepared using the crown-down technique. The teeth were randomly divided into 3 groups of 15 each for the three techniques and 6 teeth were assigned to positive and negative control groups. The first group roots were filled with Thermafil/Adseal, the second group received gutta percha/Adseal with lateral condensation technique and group 3 teeth roots were filled with Resilon/Epiphany using lateral condensation technique. Microleakage was measured using dye penetration technique. Data were statistically analyzed using ANOVA. Gutta percha/Adseal had the lowest (6.46±4.27 mm) and Resilon/Epiphany had the highest (13.47±3.03 mm) apical microleakage. Thermafil/Adseal showed higher mean apical microleakage than gutta percha/Adseal (8.43±4.49 mm). Statistical analysis revealed significant differences in apical microleakage among the three groups (P=0.0001). The results showed that gutta percha/Adseal had the lowest and Resilon/Epiphany had the highest mean apical microleakage. The microleakage of Thermafil/Adseal ranked second.

Temporary restorations should be able to seal the access cavity and prevent bacterial leakage. The aim of this study was to evaluate the amount of dye penetration through temporary restorations, namely Zonalin, Zamharir, IRM and Coltosol, into the root canal.Subjects and In this experimental study, 120 sound human premolar teeth were selected. After access cavity preparation, cleaning and shaping were accomplished using step-back technique and obturated by lateral condensation technique using gutta-percha and AH-26 sealer. The teeth were divided into six groups (n=20). In the first to fourth group, the crown was restored with zonalin, zamharir, IRM and coltozol. Group five and six were considered as positive and negative control. After keeping these teeth in 37°C and 100% humidity for 48 hours, samples were immersed in 10% Indian ink for 72 hours. After sectioning the crowns longitudinally the amounts of dye penetration in the two halves of teeth were assessed using stereomicroscope (xlO). Statistical analyses were performed using ANOVA test. Zonalin had minimum and Coltosol had maximum amount of dye penetration. There were not any significant differences between the Zonalin-Zamharir groups and between the IRM- Coltosol groups (p>0.05). Regarding different materials with ZOE base used in this study to treat tooth root, zonal in is the best as a temporary restorative material. However more comprehensive studies need to be performed about Zamharir.

The effect of smear layer on dentinal tubules is remarkable in endodontic treatments. The aim of this study was measuring the range of dye penetration in dentinal tubules with and without smear layer.

Thirty extracted human teeth used in this study. At first, segments e prepared with 5 mm length from each tooth's root and then their canals widened by a 1/4 mm diameter bur, so that the smear layer appeared. The external, superior and inferior surfaces of the segments covered by 2 layers of nail varnish. The segments divided to 2 groups of 15 samples. The first group samples immersed in 17% EDTA for 2 minutes and then in 5.25% NaOCl for 20 minutes to remove the smear layer. After that the samples immersed in 2% basic fushin for 24 hours. The second group samples immersed in 2% basic fushin without removing the smear layer. After water rinse,all samples sectioned horizontally from middle of the root and photographs was taken of each samples surfaces. After transmitting the photographs to a computer, the percentage of the dye penetration into dentinal tubules of each sample calculated by Photoshop software.

Due to results, the range of dye penetration in dentine tubules of the teeth with and without smear layer had no statistically significant difference (P-Value=0.120).

According to the result, smear layer removal have no effect on dentin permeability to dye penetration and dentin sclerosis is an important factor in this subject. Performing studies on the teeth with certain age and using other methods such as microbial permeability evaluation are needed.

Statement of Problem: Complete root canal seal is one of the most important aims of root canal treatment. Elimination of smear layer plays an important role in this regard. The purpose of this study was to compare the apical microleakage of Tubliseal sealer when 17% EDTA, 7% citric acid, or 20% citric acid was used to remove the smear layer. In this experimental study, 80 single rooted teeth were selected. The crowns were removed from cemento enamel junction (CEJ). Instrumentation of the canal was performed by the step back method. The teeth were randomly divided into 3 experimental groups of 20 and 2 control groups of 10 (positive and negative groups). Final irrigation was implemented as follows: group1; EDTA17%+NaOCl, group2; 7% citric acid + NaOCl and group3; 20% citric acid + NaOCl. Then, the groups were obturated with gutta percha and Tubliseal sealer. Lateral condensation technique was carried out in all groups. The teeth were stored in 100% humidity and 37ºC for 48 hours. The root surfaces other than the apical 2mm were covered with 2 layers of nail polish. After that, the teeth were placed in metylene blue dye for 72 hours. Then, the teeth were sectioned longitudinally with a diamond disk and the degree of dye penetration was measured. The results were statistically analyzed by one-way Variance and Post Hoc Tukey tests. A statistically significant difference was found between the groups (p < 0.05). The least amount of dye penetration (2.59mm) was belonged to 17% EDTA group and the highest mean dye penetration occurred in the group in which 20% citric acid was used (3.59mm). The results of this in vitro study indicates that when a ZOE-based sealer is used for obturation of the root canal system, EDTA is recommended to remove the smear layer. Furthermore, it can be concluded that the main purpose of removing the smear layer is not only to clean the dentinal tubules from organic and inorganic debris, but also to create a dentinal surface structure that best fits the characteristics of the sealer used for root canal obturation.

The use of proper temporary restorative materials between appointments is critical in successful root canal treatment. The purpose of this study was to compare the coronal microleakage of four temporary restorative materials including Zonalin, Zamherir, Coltosol and IRM. In this in vitro study, standard access cavities were prepared in 120 intact extracted maxillary and mandibular human first molars. Canal preparation was carried out by the step-back technique, and obturation was performed with gutta-percha and AH26 sealer using the lateral condensation technique. Teeth were randomly divided into 4 experimental groups of 25 teeth each and two positive and negative control groups, each containing 10 teeth. In each experimental group the access cavity was restored with one of the tested materials (Zamherir, Zonalin, IRM and Coltosol). In the negative control group the access cavity was filled entirely with sticky wax and in the positive control group no restorative material was applied. Dye penetration technique was used to evaluate microleakage which was measured under a stereomicroscope. Data were analyzed with one way ANOVA and post hoc Tukey tests. P<0.05 was considered as the limit of significance. Dye penetration was observed in all groups. Zonalin and Coltosol had the highest and the lowest dye penetration respectively, with a statistically significant difference (p<0.001). There was no significant difference in dye penetration between IRM, and either Coltosol or Zamherir (p>0.05). The results of this study showed that using Coltosol as a temporary restorative material can provide a better coronal seal in endodontic treatments

One of the great challenges in dental practice is root perforation sealing. At present time, there are two therapeutic methods for perforation, filling and surgical removal of affected area. In this in vitro study, we compared the sealing ability of two implanted materials, Iranian domestic Mineral Trioxide Aggregate (Root MTA) and foreign (Pro root MTA). In this experimental study, 58 selected maxilary and mandibular molar teeth were assigned into four experimental groups of 13 teeth and 2 groups of three teeth as control. Availability of the cavities was assessed prior to perforating of the furcal areas utilizing a No. 2 round bur. The defects were then filled using foreign MTA (Pro root) and Iranian MTA. All of the subjects were incubated for 72 hours. In the next step, nail polish was applied in two layers to the surfaces of the teeth, except for the perforation areas and coronal portions which were filled with Amalgam. Once the nail polish dried, they were placed into 2% fuchsine solution for 12 hrs. The teeth were then mesio-distally resected using 72mm disk and evaluated separately by two endodontists using a stereomicroscope with a magnificantion of × 20. Data were analysied by T-test and ANOVA. Results indicated that there was a significant difference between the two groups regarding dye leakage (p=0.025). Pro MTA showed a lower leakage compare to Iranian MTA (root MTA). The quality of Root MTA as a filling material may need to be improved in order to gain enough qualification as an alternative to Pro root MTA.

Patients always complain about metallic color of amalgam restorations. Covering amalgam by composite can solve this problem. Since polymerization shrinkage is a serious shortcoming in composites, application of the combined amalgam and composite restoration is one of the methods to reduce leakage in the cervical margins of posterior restorations. The aim of this invitro study was to evaluate the microleakage of amalgam/composite interface when Rely-X ARC adhesive resin cement was used in the joint. Twenty-four sound extracted premolars were chosen. Mesial and distal class II conventional cavities were prepared and the samples were divided into 4 groups of 12. In all groups, the bases of the cavities were restored with amalgam and then the remaining part was filled by composite resin. Specimens in groups 1 and 2 were restored with composite-resin, immediately after condensing amalgam without or with application of Rely-X ARC (3M, ESPE) respectively. In groups 3 and 4, composite resin were applied 24 hours after condensation of amalgam, without or with application of Rely-X ARC respectively. After polishing and thermocycling, all specimens were prepared for dye penetration and the degree of leakage was scored and analyzed using Kruskall Wallis test with p<0.05 as the level of significance. The frequency of dye penetration in different groups was obtained. The most and the least scores were observed in groups 3 and 4 respectively. No statistically significant difference was observed in different methods. None of the methods in this study could seal the amalgam/composite-resin interface.