[Evaluation of the effect of patient's age on the tooth response to electric pulp test]

Electric pulp tester is a valuable instrument to examine tooth's pulp vitality. There is no agreement about the response of immature teeth to electric pulp tester and the reason is expressed as the failure of nerve fibers' development. The aim of this study was to investigate the effect of patient's age on the tooth response to electric pulp tester. In this cross-sectional study, 300 maxillary central permanent teeth in 150 volunteers were examined by using electric pulp tester. The volunteers were classified in 5 age groups of 7-8, 9-10, 11-12, 13-4, and 30-35; and teeth lacking sound and healthy pulp were excluded. Data were analyzed using SPSS-16 software, one-way analysis of variance, and Tukey post hoc test. The average response to electric pulp tester in age groups of 7-8, 9-10, 11-12, 13-4, and 30-35 years old were 2.9 +/- 0.1, 2.8 +/- 0.1, 2.3 +/- 0.1, 2.2 +/- 0.1 and 1.8 +/- 0.1 Respectively. This indicated that by increasing teeth age, they responded to lower level of electric pulp tester. In subjects less than 14 years old, there was no significant difference between neighboring groups [P=0.3]; however, a significant difference was observed between subjects less than 14 years old and adults [P<0.001]. This study showed that immature teeth responded at higher levels to electric test; however, all teeth responded to electric pulp tester

[Effect of thermal changes on tooth response to the electric pulp tester]

The vitality pulp tests are necessary for diagnosis of pulpal disease and differentiation between endodontic and non-endodontic diseases. Thermal and electrical tests are conventional methods for evaluation of pulp vitality. The purpose of this study was to evaluate the effect of thermal changes on the tooth response to the electric pulp tester. In this study, 160 intact maxillary central incisors of 40 voluntaries were evaluated. After isolation, electric pulpal response threshold in patients were recorded. After heat and cold tests, the electrical pulp test was repeated. The degree of response was recorded. The data were analyzed using pair T-test and independent T-test. The result of this study demonstrated that the average of teeth response to the electric pulp tester before and after cold test was 1.3 and 1.7, respectively. The average was 1.4 and 1.7 before and after heat test, respectively. There was no significant difference [P<0.001] between the pulpal response before and after thermal tests [heat and cold tests]. In addition, no significant difference was found between pulpal response after heat and cold tests [P=0.25]. The response of tooth to the electric pulp tester was influenced by heat and cold tests

Effects of 810nm diode laser irradiation on flexural strength of dentin: an in vitro study

Thermal changes in laser assisted root canal therapy with the use of diode laser can predispose tooth structure to the fracture. This study evaluated the changes in flexural strength of dentin blocks after diode laser irradiations [810 nm]. A total of 60 dentinal blocks were prepared from freshly extracted teeth in three different thicknesses [300, 500 and 1000 micro m] and 20 sections in each of these thicknesses were divided randomly to the test and control groups. Samples in the test groups were irradiated at 2W power setting by scanning movement of 2mm/s of diode laser, and the controls were stored in normal saline. The flexural strength of samples was evaluated by UTM [Universal Testing Machine]. Data analysis was done with the SPSS Software 11.5. Samples of 300 micro had the lowest flexural strength [mean: 71/65 mpa] followed by 500 [116.64 mpa] and 1000 micro [217.56 mpa]. Statistical analyses showed that after laser irradiation, the flextural strength in the samples of 300 micro was significantly lower than that in the other groups [500 micro, 1000 micro] [P= 0.017]. Within the limits of this study, diode laser irradiation in laser assisted root canal therapy has no significant effect on flexural strength of root dentinal walls with the thickness of more than 500 micro. Although in areas with critical dentinal width [

[Effect of pulp tester probe placement site on the response of maxillary anterior teeth]

Electric pulp testing is used for diagnosis of the pulp status. This test is technique sensitive and hence may elicit positive or negative false response in case of inaccurate use. The optimal site for placement of the probe tip has not been determined. The aim of this study was to evaluate the effect of pulp tester probe placement site on the response of maxillary teeth. A total of 378 teeth [126 central incisors, 126 lateral incisors and 126 canines] in 67 voluntary 20-35 year-old patients were selected. Three sites on each tooth [incisal edge, labial and lingual surfaces] were tested with an electrical pulp tester and responses were recorded. Data were analyzed by Repeated Measure ANOVA test. The central incisor teeth showed significantly lower sensation threshold than lateral incisor and canine teeth [P<0.001]. The incisal edge of tooth were significantly more sensitive compared to labial and lingual surfaces [P=0.008]. This study showed that the optimum site for placement of pulp tester probe was incisal edge.

[Accuracy of single periapical radiography in diagnosis of horizontal root fracture]

Radiographic examination is a necessary step in diagnosis of horizontal root fracture. The purpose of this study was to determine the sensitivity and specificity of single radiograph for detection of horizontal root fracture. In this analytical-descriptive study, 30 human freshly extracted teeth were used. Using a hammer and clamp, the teeth were divided into two sections accidentally and then sections were attached together by cyanoacrylate glue. Two radiographs were taken; with and without a piece of human mandibular bone. Afterward, radiographs were analyzed by three expert dentists using a slide show device. The diagnostic sensitivity and specificity of single radiograph for detection of horizontal root fracture without bone was 100%, but in radiographs of teeth with bone was 82.7% and 100%, respectively. Based on the results of this study, in most cases, the horizontal root fractures can be detected by a single periapical radiograph

Cytotoxicity of cold ceramic compared with MTA and IRM

Biocompatibility is a desirable feature for root-end filling materials. In this study we aimed to compare a new material called cold ceramic [CC] with intermediate restorative material [IRM] and mineral trioxide aggregate [MTA] using Methyl-tetrazolium bromide [MTT] assay. The materials were tested in fresh and set states: [n=108]. The cytotoxicity was compared using L929 fibroblasts as an indicator; tested materials were eluted with culture medium according to ISO: 109935 standard. Distilled water and culture medium served as positive and negative controls, respectively [n=36]. The results were evaluated at 1, 24 hours and 7 days. Data were statistically analyzed by one-way ANOVA for each time interval and material status and t-tests. The cytotoxicity of the tested materials were statistically different at the various time intervals [P<0.001]. IRM was the most cytotoxic root-end filling material [P<0.001], MTA demonstrated the least cytotoxicity followed by CC. Despite displaying the greatest cytotoxicity, IRM is approved by the American Food and Drug Administration [PDA]. Cold ceramic had significantly lower cytotoxicity compared to IRM, in all but one subgroup. Further investigations are required to assess the clinical applicability of this novel material

Comparison of bond strength of different restorative materials in mandibular anterior teeth class V restorations

The aim of the present study was to determine the effect of different restorative materials on fracture resistance of mandibular teeth with class V restorations. One hundred intact mandibular incisors were selected and divided into ten groups with 10 samples in each. Three types of restorative materials; Tetric flow composite [Vivadent Ets, Schaan/Liechtenstein], Compoglass [Vivadent Ets,Schaan/Liechtenstein] and light curing glass ionomer [GC Corporation Tokyo JAPAN] were used in our study. Each of these materials were applied in cavities with 2, 3 and 4 mm widths. Group 10 was considered as the control group in which no restorations was done. All teeth were mounted in cold cure acrylic resin [Tray Resin II, Shofu Inc, Kyoto, Japan] and the samples were tested by applying shear force with cross head speed of 5mm/min in a universal testing machine [Instron corp., Canton, MA,USA]. Data were analyzed with two way ANOVA and Dunnet multiple comparisons test using SPSS 10 software package. Regardless of the types of materials, cavities with 4mm width had less bond strength than those with 2 and 3 mm widths [P-value=0.555]. In the Compoglass and glass ionomer L.C. groups, cavities with 2 and 3mm widths had significant greater strength than cavities with 4mm width [P-value=0.0002]. In groups with Tetric flow restorative material no significant difference in shear force among different widths of cavities were detected [P-value=0.4948]. The mean shear force in this group was comparable with the control group [P-value=0.0001]. In cavities 2 and 3 mm widths, there was not any significant difference in shear force between Tetric flow and compoglass restorative materials. Glass ionomer and Tetric flow had the least and the highest shear bond strength ,respectively. The results showed that although all the restorations need an average load more than masticatory forces in the mouth to fail, but Tetric flow composite with combination of chemical adhesion properties and optimum elastic characteristics was proven to be the restorative material of choice for cervical Defects with different widths

Comparison of flare-ups incidence between single and two visit endodontic treatment

The purpose of this clinical study was to find the incidence of post treatment flare-ups following single and two visit endodontic treatment procedures in teeth with vital pulps. One hundred twenty two cases with diagnosis of irreversible pulpitis were included in the study. The pulp vitality was determined by an electric pulp tester and cold test, The teeth in the single visit group were obturated a the first appointment by using AFT 26 sealer and laterally condensed gutta-percha, and those m the two visit group were medicated with calcium hydroxide then closed with a temporary filling material and obturated about 7 to 14 days later. One week after the obturation appointment, patients were asked about the occurrence of postoperative pain The level of discomfort was rated as no pain, mild pain moderate pain, or severe pain Flare-ups were defined as either patient's report of moderate to severe pain or increasing swelling Fight endodontic. flare-ups [13%] were recorded in the two visit group compared to six [9 8%] flare-ups for the single visit group.. We did not find higher incidences of post-obturation pain and flare-tips following the single visit procedures. Single visit endodontic therapy seems to be a safe and effective alternative to multiple visit treatment in teeth with vital pulps