Copper ion as a new leakage tracer

Statement of Problem: Most failures of root canal treatments are caused by bacteria

Studies showed that the most common cause of endodontic failures were the incomplete obturation of the root canal and the lack of adequate apical seal. Some in-vitro methods are used to estimate sealing quality, generally by measuring microleakage that allows the tracer agent to penetrate the filled canal

Purpose: Conventional methods of evaluating the seal of endodontically treated teeth are complicated and have some drawbacks. We used copper ion diffusion method to assess the leakage and the results were compared to dye penetration method

Materials and Method: The crowns of 21 extracted teeth were cut off at the CEJ level

After preparing the canals, the teeth were placed in tubes containing saline. They were divided randomly into 15 experimental cases; 3 positive and 3 negative controls. Positive controls were filled by single cone without sealer while the experimental and the negative control groups were filled by lateral technique. The coronal portion of gutta was removed and 9mm was left. The external surface of each tooth was coated with nail polish. Two millimeters of apical portion was immersed into 9ml of distilled water and 0.3ml of CuSO4 solution was injected into the coronal portion. After 2 days, copper sulfate was measured by an atomic absorption spectrophotometer. The teeth were then immersed in 2% methylene blue for 24 hours, sectioned and the extent of dye penetration was measured by a stereomicroscope

Results: The maximum and minimum recorded copper ion concentrations for the experimental group were 18.37 and 2.87ppm respectively. The maximum and minimum recorded dye penetrations for the experimental group were 8.5 and 3.5mm respectively

The statistical analysis, adopting paired samples test, showed poor correlation between average recorded results of two methods

Conclusion: Based on our results, there was no significant correlation between the dye penetration and the copper ion diffusion methods

incidence and risk factors of de novo skin cancer in the liver transplant recipients

Liver transplantation [LT] increases the risk of de novo malignancies including skin cancers. However, risk factors for this type of cancers have not been well studied. To determine the incidence of skin cancer in LT recipients, and to identify the risk factors of this type of cancer. We identified all adult patients who underwent LT and developed de novo skin cancer post-LT at our institution between 1996 and 2009. We excluded the patients with history of skin cancer prior to LT. We also studied a control group of patients who underwent LT during the same period but did not develop skin cancer; the control group was matched [1:2] for age, gender and geographical place of residence. Over a median [IQR] follow-up of 41.5 [18.0, 98.6] months, 23 [2.3%] of 998 patients developed skin cancer post-LT, of whom 10 were identified with squamous cell carcinoma, 9 with basal cell carcinoma and 4 with melanoma. After adjusting the confounding variables, subjects who had combined liver/ kidney transplant had 22 [95% CI: 5.1-99] times higher hazard of skin cancer compared to subjects with LT alone. Furthermore, patients who had non-skin cancer prior to LT had 23 [95% CI: 8.6-60] times higher hazard developing skin cancer after the transplant. Patients with history of alcohol consumption, as the underlying etiology of liver disease, had 4 [95% CI: 1.2-12.9] times higher hazard of developing skin cancer after transplantation. Type or duration of immunosuppression was not associated with increased risk of skin cancer post-LT. The post-LT survival outcome was not affected by the development of de novo skin cancer post-LT. Skin cancer is relatively common in LT recipients and should be monitored, particularly in patients with a history of pretransplant malignancy, recipients of combined liver and kidney transplant or having alcoholic cirrhosis as the underlying cause of liver disease

[In vitro microleakage evaluation of total-etch and self-etch bonding systems]

Bonded restorations have a number of advantages over traditional, non-adhesive methods. Adhesion reduces the microleakage at the restoration-tooth interface. Prevention of microleakage, or the ingress of oral fluids and bacteria along the cavity wall, reduces the clinical problems such as postoperative sensitivity, marginal staining, and recurrent caries, all of which may jeopardize the clinical longevity of restorative efforts. The aim of this study was to evaluate the microleakage in class V composite restoration with total-etch and self-etch adhesive systems. In this in-vitro study, 48 standard class V cavities were prepared in the buccal surface of human extracted premolars so that the occlusal margins of the cavities were in the enamel and the gingival margins in the dentin [cementum]. The teeth were divided into two groups of 24. In the first group, the cavities were restored with total-etch system [Excite] and composite. The teeth in the second group were restored with self-etch system [Prompt L-Pop] and the same composite. The teeth were thermocycled 500 times between 5 - 55°C and then were covered with nail-polish and adhesive wax axcept for 1 mm around cavities, and all teeth were immersed into the 2% methylene blue for 10 hours. The samples were mounted in polyester blocks, sectioned longitudinally at the middle of the cavities, and evaluated for microleakage under a stereomicroscope at 40x magnification. Dye penetration was scored between 0-3. Data were analyzed with Mann Whitney and Wilcoxon tests. In the enamel and dentin margins, microleakage for the total-etch group was found to be less than the self-etch group [p < 0.05]. A significant difference in the microleakage mean rank of the enamel and dentin margins was observed [p< 0.05]. Microleakage in the enamel margins was less than that in the dentin margins. Total-etch adhesive system showed a significant difference on the microleakage of class V composite restorations especially in the enamel margin

Effect of flowable composite on Microleakage of packable resin composites in class II cavities

Polymerization shrinkage is one of the most common causes of microleakage in packable composites. Various methods are recommended to reduce polymerization shrinkage and the application of flowable composites is one of these methods. The aim of the current study was to evaluate the effect of flowable composite on the microleakage of packable resin composite in class II cavities. This experimental study was performed at Dental School of Shahid Sadoughi University, Yazd [Iran] in 2006. On 32 recently extracted upper premolar teeth, the mesial and distal class II cavities with the same dimensions were created. The teeth were randomly assigned into two groups: the distal surfaces of the first group were restored with P60 while in the other group restoration was accomplished with Solitaire resin composite. The mesial aspects of the teeth were filled with Filtekflow flowable composite and other composites mentioned above. After thermocycling, the samples were soaked in 2% methylene blue solution followed by sectioning in mesiodistal direction. The degree of microleakage was evaluated by stereomicroscope with 25 X magnification. Data were subjected to the chi-square and Exact tests, statistically. The flowable composite failed to reduce the degree of microleakage in axial wall and gingival floors [p>0.05]. The application of flowable resin composite caused no effect on microleakage of class II packable resin composite restorations

[Assessment of correlation between dye penetration and electrochemical methods on apical microleakage]

The most important failure factor of root canal treatment is lack of proper seal of root canal, which leads to leakage and penetration of microorganism in to the canals. Different methods have been used to determine the apical seal This study was aimed at comparing the apical leakage using dye penetration and electrochemical methods successively used on the same teeth. For this experimental study, 31 freshly extracted anterior single root human teeth with straight root canals were selected. The specimens were randomly divided into experimental, positive and negative control groups. Root canals of the experimental and negative group were filled, and positive group were left unfilled. The external surface of each tooth was coated with two layers of the nail polisher, except for the apical 2mm and coronal portion. Leakage of the teeth were measured using electrochemical me thud. Two copper wires were used as electrodes and normal saline solution was used as electrolyte. Then coronal portions of the roots were filled using ZOE cement and coated with two layers of the nail polisher. The teeth were immersed in 2% basic Fuchsine for 48 hours and were washed in tap water. The roots were then split longitudinally and dye penetration was assessed for each tooth. The data were analyzed using t-test and Pierson correlation coefficient test. The obtained results in electrochemical methods varied from 3.1 to 54.7 Micro amper, while in dye penetration method the observed leakage was 2.5 to 6.8 mm. The coefficient correlation between the two methods was found to be 0.204 [r = 0.204, p 0.5] Since no correlation was found among the results obtained with the two methods, it is concluded that, for assessment of the marginal leakage of dental materials, various methods should be considered

[ effect of light-curing time to adhesive layer on shear bond strength of composite to dentin]

For reducing light exposure time of tooth-colored restorations, and chair time reduction, different experiments have been conducted. The purpose of this study was to determine the effect of different light exposure times to adhesive layers [Excite and Prompt L-pop] on the shear bond strength of dentincomposite interface. In this in-vitro study, 72 human intact premolar teeth were mounted in acrylic casts and enamel buccal surfaces were removed. The bonding surfaces were equalized using a surface index. Teeth were divided into six equal groups each of 12 [A, B, C, D, E, and F]. According to the manufacturer instructions, Excite adhesive in groups A, B and C, and prompt L-pop in groups D, E and F was used. A and D groups were not exposed to light, but the exposure time in groups B, E and C, F was 20s, and 40s respectively. After one week of storage in 37 degree C water, synergy composite resin was applied and then was exposed to light. The specimens were loaded by shear force with 1 mm/min cross head speed. Data were analyzed by two-way analysis of variance [ANOVA]. The means shear bond strength of groups A,B,C,D,E, and F were 3.9, 13.45, 18.1, 8.3, 24.81, 24.99 Mpa, respectively. The differences between shear bond strength of groups A, B and C and between groups B, D were statistically significant [p=0.0001]. However, the differences between groups E, F were not statistically significant. In all exposure times, the bond strength of Prompt L-pop was significantly higher than that of Excite. According to the results of this study, increase in the light exposure led to the higher bond strengths in Excite groups. In Prompt L-pop groups, 20s exposure time was adequate and by increasing the light exposure time, shear bond strength was not affected. Without light exposure in both materials, the least bond strength for the composite resins was not attainable

[ effect of ibuprofen premeditation on pulp tester responses]

The electric pulp test [EPT] is an important diagnostic aid in evaluation of pulpal vitality. It was postulated that premedication with analgesics can decrease tooth sensitivity to electric stimulation. The purpose of this study was to evaluate the effect of premeditation with ibuprofen on the responses of vital central teeth to electric pulp tester. This clinical trial study was performed on 88 intact maxillary central and lateral incisors. After taking medical and dental histories and clinical examinations, electric pulp testing was done using tooth paste as conducting medium and the results were recorded. Afterwards, each subject received a 400mg ibuprofen tablet and one hour later, electric pulp testing was conducted again. The data were statistically analyzed using t-test to compare pre- and post-medication records. The mean EPT scale of teeth before ibuprofen administration was 2.5, whereas after drug administration the mean EPT scale of the teeth was 2.7. Statistical analysis showed significant differences. This investigation showed that, although ibuprofen decreased the tooth sensitivity to electrical stimulation, but with proper attention in using pulp tester, it could still be a valuable aid in clinical practice for patient's receiving Ibuprofen

[Effectiveness of ibuprofen administration on the depth of anesthesia in inflamed teeth]

Incomplete anesthesia of inflamed teeth is a well known clinical occurrence and the purpose of this study was to evaluate the effectiveness of Ibuprofen as a premedication in improving the quality of anesthesia in patients with inflamed teeth pulps. Forty patients with the diagnosis of irreversible pulpitis in one mandibular tooth were selected. Two other teeth in the same quadrant were selected as controls. Electric pulp tester [EPT] was used in this study to evaluate the quality of anesthesia. The subjects were divided into two groups randomly, and after recording of pulp tester response in each group, one of the two drugs; ibuprofen or placebo was administered 1 hour prior to anesthesia injection. After injection, EPT measurement was recorded. The reversed EPT scale was used for evaluation of the depth of anesthesia. Data was analyzed to statistically compare the results before and after anesthesia and drug administration in cases and control group .Significantly lower TSLs were observed in the ibuprofen group [P value= 0.001]. This study concluded that preoperative administration of ibuprofen [if not contraindicated] 1 hour before local anesthesia injection is an effective method for achieving deep anesthesia during RCT of teeth with irreversible pulpitis

[In vitro comparison of the apical microleakage of laterally condensed gutta percha after using calcium hydroxide or cold ceramic as apical plug in open apex teeth]

The treatment of immature teeth with open apex by Gutta percha in one visit apexification requires an optimum material as apical barrier. One of the desirable properties of the apical barrier material is its sealing ability. This study was performed to compare the sealing ability of calcium hydroxide and a new experimental material [cold ceramic] when used as an apical barrier. Fifty extracted single canal human teeth were collected and stored in saline solution. The crowns were resected and by conventional step back method, canals were instrumented and then extended by Piso Reamer, so that, root ends were formed divergently. Samples were divided into two group including 23 teeth as study and 4 teeth as positive and negative control groups and then all teeth were mounted in a plaster cast. The two experimental materials [Cold ceramic and calcium hydroxide] were placed in the root ends for producing apical barrier, and canals were obturated with Gutta percha. The teeth in the positive and negative groups were obturated with Gutta percha, and in the negative group, cavit was placed at the end of root. In the 3 groups [calcium hydroxide, cold ceramic and positive group], all surfaces of the teeth were covered by two layers of the nail polish except 2 to 3 mm of the roots end and in the negative control group, samples were covered completely by two layers of the nail polish. Then, photographs of teeth were scanned and amount of leakage was calculated with the Photoshop software. The data were analyzed by t-test. Amount of cold ceramic leakage was less than calcium hydroxide and this difference was statistically significant [p=0.0001]. showed that apical plug with cold ceramic was more resistant than the apical plug with calcium hydroxide. The results of this study confirmed optimum sealing ability of the new experimental material for creating of apical barrier in one appointment apexification

[Effects of depression on myocardial perfusion scintigraphy]

The relationship between depression and coronary artery disease is well established; however assessment of this relationship using functional and semi-quantitative imaging [myocardial perfusion scintigraphy] was lacking. The aim of this study was to assess the relationship between the severity of depression and the severity of myocardial perfusion abnormality. Patients were assessed with rest/stress 99mTc-MIBI myocardial perfusion scintigraphy using Single Photon Emission Computed Tomography [SPECT] and Beck Depression Inventory [BDI-II]. Visual and semi-quantitative assessment of myocardial perfusion score [MPS] in a five-scale measurement for standard 20-segment-model were used. When all patients [n=167] were evaluated, no correlation was found between MPS and BDI-score. Considering only those with significant perfusion abnormality [MPS<90, n=38], negative correlation was found between MPS and BDI score [r= -0.641, p=0.017]. Also higher BDI scores were recorded for patients with inferior wall infarction when compared with those with normal or near-normal MPS [MPS>95] [p=0.097], but other myocardial walls failed to show such association. In patients with significant perfusion abnormality, the greater is this abnormality the more severe is the depression. Also patients with inferior wall infarction, have a higher BDI-score as compared with normal subjects

[Risk factors of root resorption in orthodontic patients treated with fixed appliance]

Orthodontic treatment is associated with a risk of root resorption. The aim of this study was to determine the risk of moderate and severe root resorption in orthodontic patients treated with fixed orthodontic appliance. A case-control study was performed on 70 orthodontic treated patients with moderate and severe root resorption and 70 controls matched for age, sex, duration of treatment, ANB index and headgear application. Data were gathered via patients records, pretreatment lateral cephalometry, pre and post treatment panoramic radiography and analyzed by SPSS 13, chi-square, Fischer exact and odds ratio tests. Seventy patients out of 140 have had root resorption. There was no difference in age, sex, headgear application, ANB difference and duration of treatment between case and control groups. In case group, 35 and 10 cases [50%-14.3%] and in control group 12 and 1 cases had respectively a history of asthma and allergy which was statistically significant.[P-value=0.000 and 0.005 respetively]. The odds ratio for the association between moderate to severe root resorption and history of allergy was 4.83 [95% C.I 2.217 to10.526] and history of asthma was 11.494[95% C.I 1.430 to 1.956]. This case- control study showed an association between the history of allergy and asthma and increased risk of moderate to severe root resorption. But, in order to confirm these findings, other studies including well controlled experimental studies are needed