Showing 48 results for Leakage
A. Pahlavan , M. Hasani-E-Tabatabaei ,
Volume 14, Issue 2 (8-2001)
Abstract
The purpose of this study was to evaluate the effect of pulsed Nd:YAG laser on the dentin surface by scanning electron microscope (SEM) in order to determine the optimum time and power of radiation to seal the exposed dentinal tubules. Horizontal sections were taken from newly extracted impact third molar teeth. Smear layers from the dentin surfaces were removed by phosphoric acid and all samples were treated with the pulsed Nd:YAG laser in different powers and times. The results of this study showed that the laser pulsed Nd:YAG with power: 1.7 w during 60 seconds was able to seal the exposed dentinal tubules.
E. Yasini , N Mohammadi ,
Volume 14, Issue 4 (1-2002)
Abstract
Posterior composite restorations, due to polymerization contraction, result in microleakage. Different methods have presented to reduce this phenomena. The aim of this study is to evaluate the effects of flowable and condensable composites to reduce microleakage. Seventy extracted human teeth were prepared with proximal class II cavities with gingival margin 1 mm below CEJ. The teeth randomly were divided into 7 groups. Groups I & II were restored with a dentin bonding (DB) agent plus a Prodigy condensable (Kerr Co.) composite, placing incremental or bulky, respectively.. In groups IK IV, V a dentin bonding agent was applied and then cavities were restored with Tetric flow composite resin as a base plus either a hybrid composite (Tetric ceram, Vivadent Co.) or a Prodigy condensable composite (Cond), placing bulky or incremental. Groups VI and VII were restored with a resin modified glass ionomer (GI) (Fuji II Lc Co.) as a base plus either Prodigy condensable or Tetric ceram. Restorations were polished, thermocycled, and immersed in 0.3% basic fushin. After that samples were sectioned and studied under a stereomicroscope to evaluate dye penetration. Results showed that all restorations showed some degree of microleakage and according to kruskall- wallis statistical analysis, there were not any significant differences between all groups (P-0.051). Then fore pair comparison, between groups. Mann-Whitney analysis was used and no statistical difference was observed. However. Gh DB- Tetric group showed the least microleakage and DB+ Cond (bulk) the most one. Due to lack of an" statistical difference among different materials methods, it is concluded that no method or restorative material have been able to eliminate microleakage in margins completely yet, and using a flowable composite resin, in place of resin modified glass ionomer or using a condensable composite, instead of conventional In brid composites, do not have any effect
H. Siyadat , A. mirfazaelian ,
Volume 15, Issue 2 (5-2002)
Abstract
Microkeakage is one of the most important factors in restoration longevity. Microleakage can lead to recurrent caries, marginal fracture, marginal discoloration and tooth sensitivity. Several methods have been used for in-vitro measurement of microleakage. The present study is a review of the articles,from 1967 to 1999, which have been present in Medline.
A. Pahlevan , Sh. Rahebi ,
Volume 15, Issue 3 (6-2002)
Abstract
Dentin bonding agents create stronger bonding between dental composites and dentin. But, none of them can prevent the microleakage. The important factors of progressing microleakage are the stress of polymerization shrinkage of resin composite and removal of smear layer in total-etch technique. The aim of this study was the evaluation of the effect of experimental method (modifying smear layer and etching of enamel margin) and comparison with the total-etch technique. In this experimental method, 60 extracted human molar teeth were disinfected. Then, class 5 cavities were prepared on the buccal surface and 1 mm above CEJ. The specimens were divided randomly to 6 groups with iO samples in each group. The specimens groups were:
1- Scotchbond Muiti- Purpose Plus Adhesive System (S.B.M.P.P) +Tetric composite
2- S.B.M.P.P + Ariston composite
3- Ariston liner + Ariston composite
4- S.B.M.P.P without enamel and dentin etching + Tetric composite + rebonding with Flowable Tetric
5- S.B.M.P.P without enamel and dentin etching + Ariston composite + rebonding with Flowable Tetric
6- S.B.M.P.P without enamel and dentin etching + Tetric composite
After finishing and polishing, the specimens were termocycled, stained with fushin, sectioned within the specimens and evaluated for dye penetration with stereomicroscope. Wilcoxon Sign and Kruskal Wallis tests were used for statistical analysis.
Results showed that group 3 had microleakage more than groups of 1, 2 and 5 (P<0.0 5) and this difference was significant. There was no significant difference among the other groups.
M. Hassani Tabatabaei , M. Ataei , H. Safar Charati ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: Recently, investigators have presented new methods to reduce polymerization shrinkage of composite resin restorations. It is claimed that more powerful light cure systems associated with a change in radiation patterns, lead to improved mechanical properties and reduced microleakage.
Purpose: The aim of the present study was to evaluate the effects of two curing systems, known as Soft-Start, Pulse-Delay, on microleakage and degree of conversion of composite resin restorations.
Materials and Methods: To evaluate microleakage, dye penetration method in class V cavities was applied. 30 extracted human molars filled with three different curing techniques, namely conventional, Soft-Start and Pulse-Delay, were compared. Degree of conversion was measured by FTIR Spectroscopy method immediately after sample curing. Kruskal- Wallis and Mann-Whitney test were used to compare groups.
Results: The degree of microleakage in enamel and dentin among three groups was not significantly different, however, microleakage in gingival and occlusal walls showed a significant difference among Pulse-Delay curing (P=0.001) and Soft-Start curing (P=0.28) groups, meaning that leakage gingival in wall was significantly higher than occlusal wall. This difference was not significant in conventional group. Moreover, the degree of conversion was not statistically significant among three groups (P-0.909).
Conclusion: Soft-Start and Pulse-Delay curing systems, with a two intensity start curing light, do not provide better marginal adaptation in class V composite resin restorations. It should be mentioned that polymerization degree is not also reduced in these methods.
S. Arami , M. Ghavam, M. Abbaszadeh ,
Volume 17, Issue 2 (6-2004)
Abstract
Statement of Problem: Considering that the role of collagen fibers in dentin adhesion has not been thoroughly established yet, the removal of exposed collagen fibers with a deproteinization agent such as sodium hypochlorite following etching may facilitate access of adhesive resins to a substrate that is more penetrable and less sensitive to water content which in turn would lead to a more durable bonding system. Furthermore, due to sodium hypochlorite clinical application as a cleanser or canal irrigator, its effects on the surface before etching may influence adhesive bonding strength.
Purpose: The goal of this study was to evaluate the effects of a two-minute 5.25% NaOCL application on composite restorations microleakage, using two different adhesive systems.
Materials and Methods: In this interventional experimental study, on seventy-two extracted boving incisors class V cavities were prepared on dentinal surfaces. The specimens were then randomly divided into six equal groups: A1) Acid etch (AE) dentin bonding Scontchbond Multipurpose Plus (SBMBP), A2) AE/ dentin bonding One Step (OS), B1) NaOCL/ AE/SBMPp, B2) NaOCL/AE/OS, C1) AE/NaOCL/SBMPp, C2) AE/NaOCL/OS. After bonding procedures according to the manufacturer’s instructions, cavities were restored using Z100 composite. Then, the specimens were thermocycled for 500 times in water baths of 5 and 55C. After thermocycling, the specimens were immersed in a 0.2% solution of basic fuchsin for 24 hours. A buccolingual section at the center of each restoration was obtained and examined with a stereomicroscope to evaluate color penetration into cavities. The data were subjected to two-way variance analysis.
Results: The microleakage of group B was significantly less than those of A and C (P<0.001). No significant difference was found between groups A and C (P=0.73). There were also no significant differences within groups A, B and C (P=0.852). No interaction was observered between dentin bondings and surface treatment (P=0.946).
Conclusion: The findings of this study revealed that NaOCL application after etching, for hybrid layer removal, did not make any difference on microleakage as compared with conventional bonding systems. However, its application before etching improved the seal of restoration. Additionally, there was not any significant difference between two different dentin bondings.
M. Zarabian , M. Aligholi , N. Shokouhi Nejad ,
Volume 18, Issue 3 (5-2005)
Abstract
Background and Aim: Today several materials have been used for root- end filling in endodontic surgery. Optimal properties of Pro Root MTA in in-vitro and in-vivo studies has been proven. On the other hand, based on some studies, Root MTA (Iranian Pro Root MTA) and Portland cement are similar to Pro Root MTA in physical and biologic properties. The aim of this study was to evaluate bacterial leakage (amount and mean leakage time) of four root- end filling materials.
Materials and Methods: In this experimental in-vitro study, seventy six extracted single- rooted human teeth were randomly divided into six groups for root-end filling with gray Pro Root MTA, white Pro Root MTA, Root MTA (Iranian Pro Root MTA), Portland Cement (type I) and positive and negative control groups. Root canals were instrumented using the step- back technique. Root- end filling materials were placed in 3mm ultra sonic retro preparations. Samples and microleakage model system were sterilized in autoclave. The apical 3-4 mm of the roots were immersed in phenol red with 3% lactose broth culture medium. The coronal access of each specimen was inoculated every 24h with a suspension of Streptococcus sanguis (ATCC 10556). Culture media were observed every 24h for colour change indicating bacterial contamination for 60 days. Statistical analysis was performed using log- rank test with P<0.05 as the limit of significance.
Results: At the end of study 50%, 56.25%, 56.25% and 50% of specimens filled with Gray Pro Root MTA, White Pro Root MTA. Root MTA and Portland Cement (type I) had evidence of leakage respectively. The mean leakage time was 37.19±6.29, 36.44±5.81, 37.69±5.97 and 34.81±6.67 days respectively. Statistical analysis of data showed no significant difference among the leakage (amount and mean leakage time) of the four tested root- end filling materials (P=0.9958).
Conclusion: Based on the results of this study, there were no significant differences in leakage among the four tested groups at 60 days. The results suggest that Root MTA and Portland Cement can be used as less expensive root filling materials.
A. Makarem , M. Ghavam Nassiri , M. Esmaili ,
Volume 19, Issue 4 (1-2007)
Abstract
Background and Aim: Nanoleakage can cause discoloration around restoration margins, secondary caries, postoperative sensitivity and finally loss of restoration, thus adequate hybrid layer is of primary importance in prevention of nanoleakage in adhesive restorations. Because of structural differences between primary and permanent dentin, evaluation of nanoleakge in primary teeth is very important. The aim of this study was to evaluate the nanoleakage in composite restorations following application of self -etch and total-etch adhesives in primary and permanent teeth.
Materials and Methods: In this experimental study, Cl V cavities were prepared in buccal surfaces of 20 extracted primary molars and 20 extracted premolars. Each group was divided into 2 subgroups: In group (A), Gluma One Bond and in group (B), iBond adhesive materials were applied. After silver nitrate staining, specimens were mesiodistally sectioned and polished and then SEM examination was carried out to measure the nanoleakage .Data were analyzed statistically using, ANOVA and Duncan tests with p<0.05 as the limit of significance.
Results: Factors tested had no significant effect on each other. Primary teeth showed more nanoleakage than permanent teeth (P<0.05). Mean nanoleakage was significantly higher in cervical than occlusal margins (P<0.05) and also in iBond than in Gluma One Bond in primary teeth (P<0.05). In permanent teeth, the lowest nanoleakage was observed in Gluma One Bond.
Conclusion: The result of this study indicates that the use of total etch dentin adhesives (Gluma One Bond) in bonded restorations results in less nanoleakage in primary and permanent teeth.
M. Khoroushi , A. Abedini ,
Volume 20, Issue 1 (5-2007)
Abstract
Background and Aim: 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.
Materials and Methods: 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.
Results: 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.
Conclusion: None of the methods in this study could seal the amalgam/composite-resin interface.
H. Safarcherati , H. Alaghehmand , R. Arianfar ,
Volume 20, Issue 2 (5-2007)
Abstract
Background and Aim: An important purpose of adhesive dentistry is restriction of cavity preparation to carious dentin removal and conservation of sound dentin. Application of caries disclosing agents and cavity disinfectants can help achieving this goal. The aim of this study was to evaluate the effect of caries disclosing agents and cavity disinfectants on microleakage of composite resin restorations.
Materials and Methods: This experimental in-vitro study was performed on class V cavities in 48 extracted human sound premolars. The teeth were randomly divided into four equal groups. In group 1 caries detector dye (Seek, Ultradent, USA) and in group 2 cavity disinfectant (Consepsis, Ultradent, USA) were applied on dentinal surfaces. In group 3 both mentioned materials were applied. Group 4 was considered as control group. PQ1 bonding agent and Amelogen composite were used to restore the cavities. Gingival microleakage was assessed by dye penetration. Data were analyzed by Kruskall Wallis and Dunn tests. P<0.05 was the level of significance.
Results: Group 2 showed the least and group 4 showed the highest microleakagehowever no statistical significant difference was found among the groups.
Conclusion: The use of caries disclosing agent (Seek) and cavity disinfectant (Consepsis Liquid) did not adversely affect the sealing ability of dentin bonding resins.
M. Saatchi , L. Etesami ,
Volume 20, Issue 2 (5-2007)
Abstract
Background and Aim: The final objective of root canal therapy is to create a hermetic seal along the length of the root canal system from the coronal opening to the apical termination and to accomplish the best adaptation of obturation material with canal walls. The purpose of this study was to compare the microleakage during lateral condensation of 0.04 and 0.02 tapered gutta-percha master cones.
Materials and Methods: In this experimental in vitro study, seventy two single canal teeth were selected and the crowns were removed. Canals were prepared using a step-back technique. Patency of the apical foramen was maintained and the teeth were divided into two experimental groups of 31 each Ten teeth were used as control group, out of which five served as negative and five as positive controls. The first and second groups were obturated with 0.02 and 0.04 tapered master cones respectively. All the teeth were obturated using lateral condensation technique. The teeth were placed in 100% humidity and 37oc for three days. The roots were coated with two layers of nail varnish and one layer of stick wax except for the apical 2 mm. Teeth were placed in Pelikan ink for one week and sectioned vertically. The maximum depth of dye penetration for each tooth was recorded by two evaluators with stereomicroscope. The results were statistically analyzed using t-test with p<0.05 as the level of significance.
Results: The mean linear dye penetration for the first and second groups was 2.53 0.88mm and 4.89 1.20 mm respectively. The difference was statistically significant (P<0.001).
Conclusion: The results of this study showed that 0.02 tapered gutta-percha master cone, provided a significantly better apical seal than 0.04 tapered gutta-percha master cone.
M. Tabrizizadeh , H. Zandi , Z. Mohammadi , A. Molana ,
Volume 20, Issue 3 (6-2007)
Abstract
Background and Aim: Incomplete root development caused by trauma ,caries, or pulpal pathosis requires special attention and treatment . Although calcium hydroxide apexification has been used successfully for years but it requires patient cooperation and multiple appointments . Single visit apexification with MTA has been used in recent years. The purpose of this study was to compare bacterial microleakage of two types of MTA (Made in Iran and Brazil) applied as apical barrier in open apex teeth.
Materials and Methods: 48 single root teeth were used in this experimental in vitro study. Teeth apices were prepared as open apex teeth. For canal obturation the 4mm of root end was filled with 2 types of MTA (white Iranian MTA salami co. Iran and Angelus MTA Angelus Brazil) from coronal access. Teeth were mounted in self-cured acryl and put in BHI microbial culture. A suspension of Staphylococcus epidermidis was injected from coronal area into the root canals.The teeth were incubated and examined every 24 hours for microbial microleakage, indicated as turbidity in culture. Data were analyzed using Fisher exact test with p<0.05 as the level of significance.
Results: Microleakage appeared after 15 days in all Iranian and after 17 days in Angelus MTA samples.There was no significant difference between microleakage of two types of MTA (P = 0.48).
Conclusion: Based on the results of this study, there was no significant difference between microleakage of Iranian and Angelus MTA. If further studies confirm other physical, chemical, biological and sealing properties of Iranian MTA, it could be recommended for clinical application
S. Khedmat , M. rezaeifar ,
Volume 20, Issue 3 (6-2007)
Abstract
Background and Aim: Complete obturation of the prepared root canal is an essential step in endodontic treatment. Combination of gutta-percha and a sealer is widely used in clinical practice for root canal obturation, thus microleakage studies on sealing properties of these materials constitute an important part of endodontic researches. The aim of this study was to evaluate the microleakage of three root canal sealers: Apexit, AH26 and Dorifill by electrochemical method.
Materials and Methods: In this experimental study, 55 extracted human maxillary and mandibular cuspids were used. The coronal part of teeth were removed and the root canals were prepared using the step-back technique. The specimens were randomly divided into 3 groups of 17 samples each. Teeth in each group were filled with one of the sealers and gutta-percha by lateral condensation technique. 4 specimens served as positive and negative controls. An electrochemical method was used for evaluation of apical leakage with the electrical source potential of 10 V. Measurements of current flow through the test system were recorded every 72 hours. Data were analyzed by Kruskall Wallis and Mann Whitney tests. P<0.05 was considered as the level of significance.
Results: All specimens of the three groups showed low initial leakage that increased during the test period. The mean leakage in Apexit group was higher than AH26 and Dorifill groups. The lowest mean leakage was related to Dorifill group. Although no statistically significant difference was observed between this sealer and AH26.
Conclusion: The results of this study revealed that the best apical seal was obtained using Dorifill and AH26 sealers. The poorest result was observed in Apexit.
M. Tabrizizadeh , Z. Mohammadi , Mj. Barzegar Bafruyi ,
Volume 20, Issue 4 (1-2008)
Abstract
Background and Aim: Sealing the root canal system is of great importance in endodontic treatment especially in infected teeth. Several materials have been introduced for this purpose. The aim of the present study was to evaluate the sealing ability of MTA as an orthograde root filling material and compare it with laterally condensed gutta-percha with sealer.
Materials and Methods: Thirty-six extracted human maxillary central and canine teeth were used in this experimental study. After preparation and surface disinfection with 1% NaOCl solution, the crowns of the teeth were cut at cemento-enamel junction.Roots were randomly divided into four groups: two experimental groups of 15 roots each (gutta-percha with AH26 sealer and MTA) and two control groups of 3 roots each (positive and negative). After root canal preparation and filling, the sealing ability of each technique was assessed by immersion in 1% methylene blue dye for 72 hours. Then the teeth were cleared and the extent of dye penetration was measured with a stereomicroscope. Data were analyzed by T-test with P<0.05 as the level of significance.
Results: The results showed that the mean microleakage was 1.1mm (SD=2.1) in the gutta percha group and 3.4mm (SD= 2.1) in the MTA group.This difference was statistically significant (P=0.013).
Conclusion: Based on the results of this study, canal obturation with gutta-percha and AH26 sealer may provide a better apical seal compared with MTA. However, further studies on microbial leakage are needed for more precise evaluation of the sealing ability of MTA.
A. Pahlavan, M. Ghavam, S. Arami, E. Yasini, M. Mirzaie, H. M.kermanshah, M. Hasani Tabatabaie, M. Bayrami,
Volume 21, Issue 1 (10-2008)
Abstract
Background and Aim: Because of polymerization shrinkage and high viscosity of posterior composites, there are some difficulties in using them in posterior restorations. Several methods have been represented to reduce the effect of shrinkage. The aim of this study was to investigate the effect of curing flowable composites under condensable ones in adaptation and microleakage reduction of posterior composite restorations.
Materials and Methods: In this experimental in vitro study, forty class II MO cavities were prepared on extracted intact molar and premolar human teeth. Gingival margins were placed 1 mm apical to CEJ. The teeth were divided into two groups. In group 1, flowable composite (Filek Flow, 3M, ESPE, USA) with 0.5-1 mm thickness was applied and cured following application of bonding agent (Single Bond, 3M, ESPE, USA). The rest of the cavity was filled by condensable composite (p60, 3M, ESPE, USA). In group 2 the flowable composite was not cured, and the condensable composite was applied in two increments. After light curing of composites, all the specimens were thermocycled and then immersed in 0.3% basic fuschin. Specimens were sectioned and evaluated for degree of dye penetration under a stereomicroscope. Data were analyzed by Mann-Whitney test with p<0.05 as the level of significance.
Results:. There was no significant difference between the two studied groups regarding microleakage.
Conclusion: Based on the results of this study, neither cured nor uncured flowable composite under condensable composite can omit microleakage in posterior composite restorations.
Sh. Shahi, A. Molaee Asl,
Volume 21, Issue 1 (10-2008)
Abstract
Background and Aim: 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.
Materials and Methods: 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.
Results: 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).
Conclusion: The results of this study showed that using Coltosol as a temporary restorative material can provide a better coronal seal in endodontic treatments
H. Moosavi, S. Sadeghi,
Volume 21, Issue 1 (10-2008)
Abstract
Background and Aim: Application of varnish and dentin bonding agents can effectively reduce microleakage under amalgam restorations. Also rebonding may show some effects on microleakage and its complications. The aim of this study was to evaluate the effect of liner/ adhesives on microleakage of Class V amalgam restoration with or without rebonding.
Materials and Methods: In this in vitro study Class V cavities were prepared on sixty sound human maxillary premolars with the gingival floor 1mm below the CEJ. Cases were divided into six groups of ten teeth each. Specimens in group 1 and 2 were lined with Copalite and Scotchbond Multi-Purpose (SBMP) respectively. In the third group (control) no liner was applied. The teeth were then restored with spherical amalgam. Specimens in group 4 to 6 received the same treatments but after filling, the interfaces of restorations and teeth were etched with 37% phosphoric acid gel, rinsed and dried. Adhesive resin of SBMP was applied over amalgam and tooth margins and polymerized (rebonding). Specimens were thermocycled, exposed to dye and sectioned. Microleakage was graded (0-3) using a stereomicroscope at X40 magnification. Data were analyzed with Kruskal-Wallis, Mann-Whitney and Wilcoxon pair wise statistical tests. P<0.05 was considered as the limit of significance.
Results: The groups lined with SBMP showed the lowest and the groups without liner the highest microleakage (p= 0.001). Significant difference was observed in microleakage mean rank of enamel and dentin margins (p=0.048). Rebonding with resin did not improve the seal (p> 0.05).
Conclusion: Based on the results of this study, total etch adhesive system had significant effect on microleakage of Class V amalgam restorations especially in cervical margin. Rebonding did not show a significant effect on microleakage.
H. Afshar, J. Mahmoodian, P. Motahhary, A. Khanlarpoor,
Volume 21, Issue 2 (11-2008)
Abstract
Background and Aim: Pit and fissure sealant therapy, is one of the most effective methods, in prevention of occlusal caries. Saliva contamination before curing the resin can increase the risk of failure in this method. The purpose of this study was to evaluate the effect of saliva contamination prior to curing on microleakage of pit and fissure sealants.
Materials and Methods: In this experimental in vitro study 21 sound human pre molars were selected and two standardized V-Shaped fissures were prepared on both buccal and lingual surfaces, then they were randomly divided into two equal groups. In the control group, the sealant was cured without any saliva contamination and in the case group, the sealed teeth were immersed in artificial saliva for ten seconds before curing. After thermocycling the samples were immersed in 2% fouchsin solution for 24 hours and then sectioned longitudinally in bucco - lingual direction. The specimens were then fixed and assessed under stereomicroscope to determine microleakage and dye penetration using paired student t. test. P<0.05 was considered as the level of significance.
Results: Analysis of data showed no significant differences in microleakage, between the two groups (p=0.178).
Conclusion: According to the results of this study saliva contamination of uncured sealant had no influence on microleakage.
F. Shirani, Mr. Malekipoor, P. Mirzakoochaki, M. Eravani,
Volume 21, Issue 2 (11-2008)
Abstract
Background and Aim: Microleakage has been always a major concern in restorative dentistry. The curing contraction of composites still presents a problem with controlling microleakage and postoperative sensitivity. The aim of this study was to investigate the effect of flowable and dual-cure resin composite liners on gingival microleakage of packable resin composite restorations.
Materials and Methods: Sixty Class II cavities with cervical margins 1 mm below the CEJ were prepared in 30 extracted human molars. The teeth were randomly divided into five groups of 12 each. In control group, each tooth was restored incrementally with Tetric Ceram composite without applying any liner. In the second and forth groups, flowable materials- Tetric Flow and dual-cure composite resin cement Relay X ARC were placed respectively as a 1-mm thick gingival increment and cured before the resin composite restoration, whereas, in the third and fifth groups liners were cured with the first increment of packable composite.The restored teeth were stored for one week in distilled water at 370C, and thermocycled between 50C and 550C, sealed with nail varnish except the tooth - composite interface in cervical restoration margins and immersed in 2% basic fuchsin for 24 hours. Dye penetration was evaluated using a stereomicroscope with 28x magnification. The data were analyzed by Kruskal-Wallis and Mann-Whitney U-tests with p<0.05 as the level of significance.
Results: The results of this study indicated that there were significant statistical differences between control - cured flowable liner, control-flowable liner without separately curing, control-cured dual cure composite resin cement groups.However there were no significant differences between dual-cure composite resin cement without separately curing-control,cured flowable liner-cured dual cure composite resin cement, flowable liner without separately curing-dual cure composite resin cement without separately curing groups.
Conclusion: The results of this study indicated that none of techniques could thoroughly eliminate microleakage in gingival floor, however the effect of flowable or a dual-cure liner on reducing the gingival microleakage was found to be statistically significant in tested restorative material.
E. Yasini, M. Mirzaei, A. Pahlavan, M. Ghavam, M. Hasani Tabatabaie, S. Arami, H. Kermanshah, Sh. Tabatabaie,
Volume 21, Issue 2 (11-2008)
Abstract
Background and Aim: Amalgam is one of the mostly used restorative materials, but has some disadvantages. Microleakage is one of the short comings of amalgam which may lead to sensitivity and recurrent caries. The aim of this study was to evaluate the effect of three dentin bonding systems on reduction of microleakage in amalgam restorations.
Materials and Methods: Class II amalgam restorations were made in 40 noncarious molar and premolar teeth. Then the specimens were divided into four equal groups. Scotch Bond Multi Purpose, Single bond,
iBond, were used as liner in groups one to three respectively and in group four no liner was used. The teeth were restored with high copper spherical amalgam. After thermocycling for 500 cycles at 50C and 550C, the specimens were immersed in basic fuchsin for 24 hours, bisectioned mesiodistally and evaluated under stereomicroscope at X25 for dye penetration. The data were analyzed by Kruskal-wallis and Scheffe. P<0.05 was considered as the level of significance.
Results: The groups showed significant difference (p=0.003). The group four had significantly less microleakage than the first and second groups (p<0.05). The second and third groups showed significantly different microleakage (p=0.038).
Conclusion: Based on the results of this investigation applying dentin bonding agents has no effect on reducing microleakage in amalgam restorations, however more studies are recommended.
