Journal of Dental Medicine
Year:2016 | Volume:29 | Issue:1|Papers Count:11

Background and Aims: In response to esthetic demand and use of zirconia abutments; detection of implant abutment connection misfit is so important. The purpose of this study was to evaluate the sensitivity and specificity of radiographic images in the detection of abutment-implant connection misfit in zirconia and titanium abutments of three different implant connections.Materials and Methods: One regular implant fixture of Branemark, Noble active and Replace systems were mount in acrylic models. Two pieces titanium and zirconium abutments were attached to the implants, once with correct adaptation and once with 0.5 mm spacer. Digital radiographic images were taken of 12 created states with zero degree vertical and horizontal inclination and evaluated by 10 specialists in implant treatment in two different time penods. Data were analyzed using Kappa analysis.Results: Interclass Correlation Coefficients (ICC) of the agreement of answers in the first and second times were 97.4 and 97.5, respectively (P<0.001). Sensitivity of detecting gap in all groups was acceptable (95-100%) except titanium abutment in Noble active which was the lowest value (35%). Specificity of all groups were acceptable (80-95%) except zirconia abutments in Noble active and Replace with 45% and 30% values, respectively, and titanium abutments in Branemark had the highest value (95%).Conclusion: The sensitivity of radiographic images in detection of abutment-implant connection misfit only in Noble active with titanium abutment was not acceptable. Specificity of radiographic images in the absence of gap in titanium abutments was more favorable.

Background and Aims: Slow polymerization rate in early stage of light curing process leads to higher monomers movement and entering in polymer network that cause higher mechanical properties.The aim of this study was to evaluate the effect of light activation methodes (immediate, 5 and 10 minutes delay) on the push-out bond strength of cemented fiber posts in different regions of root canal with two types of resin cements.Materials and Methods: In sixty extracted human single canal, the teeth were decoronated from cement enamel junction and after root canal therapy, FRC postec plus were cemented with two resin cements, Duolink and Variolink 2, in three curing methods; immediate, 5 and 10 minutes of delay. After storing in a dark place for 24 hours, they were cut into three sections: coronal, middle and apical. The push-out bond strength test was performed using a universal testing machine. The failure modes were observed using a stereomicroscope. Data were analyzed using ANOVA and Tukey post hoc test (P<0.05).Results: In Duolink, immediate light curing had significantly higher bond strength than that of two delayed methods (P>0.05). In immediate light curing method, regardless of root region, Duolink had higher push-out bond strength than that of Variolink 2 (P=0.02). In all subgroups, there were reductions in the bond strengths from coronal to apical. Mixed failure at the cement-fiber post interface was predominent in all groups.Conclusion: 5 and 10 minutes delay caused reduction in the push-out bond strength for Variolink 2 but did not have significant effect for Duolink resin cement.

Background and Aims: Estimating the canal length is essential for reaching to a proper endodontic treatment. Any error and miscalculation in estimation of the working length, especially in curved canals, can result in complication during and after root canal therapy. The introduction of digital radiography has enabled us to measure curved canal length. The purpose of this study was to evaluate the calibration tool of Complementary Metal Oxide Semiconductor (CMOS) digital system in estimation of working length.Materials and Methods: In this in-vitro study, 80 extracted molar teeth were selected and randomly divided into three groups based on angle and radius of canal curvature. A 5 mm orthodontic wire was placed on the lateral surface of the root. Conventional radiographs were taken after insertion of endodontic file in the apical third of root canals. Radiographic images were scanned and imported to the software of CMOS digital system. Two observers estimated the file lengths with and without using calibration tool of digital measurement software. The correlation between observers was evaluated and then data were analyzed using Paired T-test with 95% confidence.Results: Overall agreement between observers was good. There was no significant difference between the mean values of calibrated measurement and true file length in the basis of canal curves (P>0.001). However, there was significant difference between the mean values of uncalibrated measurement and true file length in the basis of canal curvature (P<0.001).Conclusion: The calibrated measurement of file length was more accurate than that of the uncalibrated file length measurement.

Background and Aims: Nowadays lasers are used as alternatives to the tooth preparation because of reducing pain and bloodshed. The aim of this study was to observe the effect of ArF laser on the dental hard tissues.Materials and Methods: For this research human molar teeth with no caries or dental restoration and enamel cracks were used. Irradiation laser energies were taken 95, 70 and 50 mJ for enamel and 80, 70 and 50 mJ for dentine. Then, for each of energy values pulse numbers (repetition rate) were adjusted at 200, 400, 600, 800, 1000 and 1500. Ablation was carried out without water spray on both enamel and dentine. Finally, the dimensions of ablated areas were measured by using a camera connected to the computer and results were applied in graphs.Results: For each energy value, the ablation dimension increased by increasing pulse numbers. Ablation depth in dentine was more than that of for enamel. Trends of graphs for dentine and enamel were the same. SEM images of ablations by 95 mJ energy on enamel and 80 mJ energy on dentine showed sharp edges.Conclusion: Ablation depths increased by increasing pulse numbers, for each energy level. However, this increase was not that as expected, because the lack of water spray while irradiating.

Background and Aims: Debonding at the cement-dentine interface is the main reason of failure in restoration of endodentically treated teeth with fiber posts. The aim of this study was to compare the effect of Starfill 2B danville and Panavia F2 kuraray cements on the retention of fiber posts to root canal dentin.Materials and Methods: Twenty extracted mandibular premolar teeth which had single root canal were endodentically treated and decoronated. Teeth were randomly divided into 2 groups, (n=40). Fiber posts were cemented using 2 dual cure resin cements. Group A was cemented with Starfill 2B Danville and group B was cemented with Panavia F2 Kuraray. Each root was mounted in acrylic resin and then sliced in 2 parts. The retention strength of each specimen was determined using push-out test using a universal testing machine. Data was analyzed using T-test.Results: The retentive strength for groups A and B were 48.16±12.11 and 61.44±9.16 MPa, respectively. There was significant difference in the retentive strength between group A and B (P<0.05).Conclusion: It seems that type of cement had effect on the retention of fiber posts. Panavia F2 Kuraray resin cement significantly provided higher retention than that of Starfill 2B Danville cement.

Background and Aims: Micro leakage is one of the most common problems in bonding systems, which cause different clinical shortcomings such as post operative sensitivity, marginal discoloration and pulp necrosis that can decrease those using bonding systems. The aim of this study was to compare the micro leakage of three self etch bonding agents (generation 6 and 7) in class 5 composite cavities.Materials and Methods: In this experimental study, 30 facial class 5 cavities were prepared in 30 human premolar teeth which were freshly extracted for orthodontic purposes. Cl V cavities were prepared in 2*3*2 mm dimensions. Occlusal margins were in enamel and gingival ones in cementum and randomly divided into 3 groups of 10 each. Then the cavities were treated by clearhil SE Bond (Kuraray, Japan), G Bond (GC, Japan), and Opti Bond Solo Plus (Kerr, USA), according to the manufacturers’ insductions. Then the cavities were filled using Z100 resin composite. The specimens were then immersed in a 50% AgNo solution for 24 hrs. Then, the teeth were cut buccolingually to be evaluated for dye penetration with stereomicroscope. Data were analyzed using Kruskal-Wallis test.Results: This study revealed that Opti bond solo plus had type1 micro leakage (dye penetration up to 1.3 of cavity) in 80% of specimen, and type 4 micro leakage (along axial wall) in 10%. Clearfil SE bond had no leakage in 50%, type1 in 40% and type 2 (up to 2.3 of cavity) in 10%. But there was no significant difference in the micro leakage at the gingival margins between 3 groups (P>0.05).Conclusion: Clearfil SE Bond and G bond could prevent micro leakage more effectively than that of Opti Bond Solo Plus on the occlusal margins. However, no difference in the micro leakage on the gingival surfaces was found.

Background and Aims: Cleaning and shaping is one of the most important stages in endodontic treatment. Single-file systems save time and reduce the risk of transmission of pathogens. This in vitro study was aimed to compare the rate of canal transportation after the preparation of the stimulated resin root canal with two single-file systems, namely Wave one and Reciproc.Materials and Methods: Thirty stimulated resin root canal blocks with size 8.0. 02 K file were randomly divided into two study groups. The preparation in Group A and Group B was performed using Reciproc and Wave one files, respectively. Pre and post- preparation photographs were taken and the images were superimposed to evaluate the inner and outer wall’s curvature tendency at three points (apical, middle and coronal) using AutoCad pragram. Data were analyzed using T-test.Results: Based on the results, the degree of transportation in the inner and outer walls of the canal was less at the level of 3 millimeters (P<0.001) and there was no significant difference between the two groups regarding the deviation at the levels of 1 and 5 millimeters (P>0.05).Conclusion: Wave one showed better performance in the middle third of canal and this system maybe recommended.

Background and Aims: The zirconia coated FRC posts (Ice light) is the next generation of aesthetic posts , ice light features 70% fill of zirconia enriched, parallel glass fiber for exceptional strength. Its flexibility is close to dentine so stress is distributed. The aim of this study was to evaluate the effect of post type (FRC post and the zirconia coated FRC post) on the retention to the root canal wall.Materials and Methods: 20 extracted human premolar teeth with 14 mm length were selected. After post space preparation, the teeth were randomly divided into two groups: Group1: the zirconia coated FRC post (Danville, USA) Group2: FRC post (RTD DT light post, France). All posts were cemented with a dual-cure resin cement (Panavia, Kuraray, Japan). All specimens were mount in acrylic cylinders, and the push-out test was done using a universal testing machine (Instron 5500 R, USA) at 1 mm/min speed. Data were analyzed using T-test.Results: The retentive strengths were in coronal (75.27+14.81 MPa), in middle (64.38+15.29 MPa) and in apical (51.46+13.29 MPa) for the zirconia coated FRC post, and also were in Coronal (59.16+1.91 MPa), in middle (66.83+12.32 MPa) and in apical (67.88+17.47 MPa) for the FRC post. There was no significant difference in mean retentive strength between two groups in each region (P=0.07).Conclusion: The FRC post and zirconia coated FRC post had similar retention to the root canal walls.

Background and Aims: The aim of this study was to assess the oral health behaviors in women with addiction history.Materials and Methods: A cross-sectional study was carried out in women drug treatment centers under the supervision of Welfare Organization of Tehran province in Iran. Data collection process was conducted in three centers including a questionnaire with an interview format, clinical examination, and Chi-Square test and MANOVA for statistical analysis.Results: The mean age of 95 women participating in this study was less than forty, whereas the age of starting drugs was twenty two. A majority of the patients were unemployed (71%) and more than that of two-third did not have a diploma education. Almost half of dentate participants had never or rarely brushed their teeth. Most of them had never used dental floss, while more than half had three or more times snacks or sweet drinks and more than three-fourth were daily smokers. The MANOVA analysis showed that the type of clinic to be visited, age, used stimulant, drug dependency length, the last time a dentist being visited and the brushing period had a statistically significant relationship with Decayed Teeth (DT), Missing Teeth (MT) and Filled Teeth (FT) (P<0.05).Conclusion: Women with the prior drug addiction history had an unpromising oral health status which was obvious in their self-perceived oral health. Taking the appropriate preventive and therapeutic actions aiming for promoting oral health status of them seems to be necessary.

Background and Aims: Despite advances in trauma management, treatment of the consequent infections has remained a major challenge. Antibiotic prophylaxis has been widely applied to reduce such infections. Although bacteria are present in most body parts, severe infections after treatment are less frequent in the head and neck of healthy individuals. The aim of the present study was to review the reasonable application of antibiotic prophylaxis in maxillofacial trauma.Materials and Methods: In this review article, PubMed and Google Scholar databases were searched for studies on antibiotic prophylaxis in maxillofacial trauma published during 2000-2014.Conclusion: Antibiotics were not prescribed for tears and small clean wounds in the face and mouth. However, prophylaxis was applied for extensive mouth injuries which involved the facial skin. In case of maxillofacial fractures, 24-hour administration of antibiotics sufficed for compound fractures of the mandible and other parts of the face. Antibiotics were not required in other types of fractures. Prophylaxis should be applied over short pre- or post-operative periods based on the severity and complexity of maxillofacial fractures and their relations with intra- and extraoral environments. Apparently, more detailed studies are warranted to further clarify the subject.