Journal of Dental Medicine

Background and Aims: Although composite resin restorations have many advantages, they can lead to several clinical problems. The primary reason for these problems is microleakage. The aim of this study was to compare the rebonding effect on microleakage of class V composite restorations using two low viscosity resins.
Materials and Methods: In this in vitro study, 60 class V composite restorations were performed in buccal and lingual surfaces of human extracted premolars with the occlusal margin in enamel and the gingival margin in dentin/cementum. The teeth were randomly divided into 3 groups: (I) restorations with no rebonding, (II) restoration margins rebonded with an enamel adhesive (Margin Bond), (III) restoration margins rebonded with a specific unfilled resin. The specimens were then thermocycled and immersed in 0.5% fuchsin dye solution. The samples were sectioned longitudinally and observed under a stereomicroscope for assessment of microleakage. The data were analyzed by Kruskal-Wallis, Wilcoxon and Mann-Whitney tests. P<0.05 was considered as the level of significance.
Results: Statistical analysis showed a significant difference in the microleakage of gingival margins (P<0.0001), but not in enamel margins (P=0.148). Microleakage at the gingival margins of group (III) was significantly less than that of group (II). Group (I) showed the highest amount of microleakage.
Conclusion: Rebonding by a low viscosity resin reduces microleakage at the gingival margins of class V composite restorations, but has no significant effect on the occlusal margins.

Background and Aims: Discoloration of resin composites is considered to be the major factor in esthetic restoration failures. The aim of this study was to evaluate the color stability of resin composites after rebonding with two different adhesive materials.

Materials and Methods: Forty five composite disc samples were divided into three groups (n=15). The surface of specimens was finished by polishing disc and rubber. In group 1, any additional phase was not performed. In group 2, composite discs were etched by %37 orthophosphoric acid, then Margin- bond was used for rebonding. In group 3, the etching procedure was in the same manner used for group 2, but Permaseal was used after etching. After the first phase of spectrophotometric measurement, the specimens were dipped in coffee mix for 3 weeks for aging the specimens. Then the second phase of spectrophotometric evaluation was performed. Collected data was analyzed using one-way ANOVA test followed by Tukey test. P<0.05 was considered as the level of significance.

Results: The mean total color difference (∆E) observed in groups 1 to 3 were 1.4±0.34, 5.24±1.51, and 7.44±1.34, respectively. Statistical significant differences were shown between the groups (P<0.001).

Conclusion: Rebonding with adhesive materials used in this study did not increase the color stability of composite restorations.

  Background and Aims: The ability of composite restorations to prevent microleakage needs desirable bonding material for proper sealing . The purpose of this study was to evaluate class V composite restorations microleakage in premolars with/without electric current while applying variant dentin bonding in vitro.

  Materials and Methods: 120 non-carious human premolars were used for this study and standardized class v cavities were prepared. The tooth roots were cut by discs at a distance of 5 mm from CEJ and pulp tissue was removed. The teeth were divided into six groups of 20. In the first group, electric current was applied, Single bond (3M ESPE, St Paul, MN, USA) with a broom motion attached to the cathode and a sponge containing bonding was used as anode. The used current was 15µA and the Single bond in the second group was used without electricity. Then two bondings PQ1 (Ultradent, Germany) and Optibond solo plus (Kerr, USA) were used with and without electricity. After adhesive application and curing the bonding agents, cavities were restored by a composite (Valux Plus). The root ends were sealed by wax and all teeth surfaces, except 1 mm around the restorations were covered with a nail varnish. The specimens were thermocycled for 1000 cycles and placed in fushin for 24 hours and were then sectioned vertically and examined under a stereomicroscope. Data were scored on a 0-4 scale based on microleakage at the gingival margins and analyzed using Kruskal-Wallis and Mann-whitney test.

  Results: Based on the results, the extent of microleakage in the groups of electric current was significantly less than the groups without using the electric current (P=0.05). The lowest degree of microleakage was found in PQ1 group, and the greatest difference between the groups with and without electricity was also found in PQ1 group. Single bond and Optibond Solo Plus with electric current showed a lower degree of microleakge.

  Conclusion: The result showed that use of electric current during the application of dental adhesives could reduce the extent of microleakage.

  Background and Aims: It is crucial to verify the relationship between root apices and maxillary sinus floor in some surgical procedures like extraction and implant placement or in orthodontic movements like intrusion. Protrusion of roots into the sinus increases the risk of post extraction pneumatization which in turn decreases the available bone at the implant or denture sites. The aim of this study was to determine the panoramic radiology accuracy for defining the relationship between posterior root apices and the maxillary sinus floor by Cone Beam CT (CBCT).

  Materials and Methods: Paired panoramic radiographs and CBCT images of 117 subjects were examined. 452 posterior maxillary roots including second premolar, first and second molar were classified by the means of the relationship with maxillary sinus floor. CBCT was used as Gold standard method, and the agreement of panoramic findings with CBCT was examined statistically. Data were analyzed using Chi-square and Multiple logistic regressions.

  Results: Agreement of the panoramic and CBCT results were seen in 57.7% of all cases. Roots which had no contacts with the sinus floor (class 0) showed a high agreement of 89.5% between two imaging techniques. Roots in contact with sinus floor (class 1) showed 58.8 % and cases with root protrusion into sinus cavity (class 3, 4) showed 50% of agreement (P<0.001). Also in 36% of cases with no protrusion into the sinus cavity (class 0, 1, 2), panoramic showed protrusion. The agreement for the premolar was higher than molars (P<0.001)

  Conclusion: The majority of roots which their images were projected on the sinus cavity had no vertical protrusion in CBCT cuts. Considering the results, in these cases CBCT can be recommended.

  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.