Glucose Penetration Research Articles

Combining heterogeneous photocatalysis and enzymatic catalysis via membrane: Conversion of biomass for H2 production from water

Solar reforming cellulosic biomass into hydrogen is an attractive research topic for sustainable biomass waste utilization and renewable energy development. To exert the advantages of enzymatic catalysis and heterogeneous photocatalysis, a glass fiber membrane integrated process that combines enzymatic hydrolysis of cellulose with sacrificial photocatalytic H2 production from water under mild condition has been proposed as an example of integrating enzymatic catalysis and heterogeneous photocatalysis. Specifically, a low−cost Cu0.5Ni0.5−TiO2 photocatalyst has been developed with presenting remarkable H2 production performance even comparable with Pt−TiO2 under UV light irradiation. The synergistic effect of Cu and Ni co−deposition onto TiO2 has been found to improve the photocatalytic H2 production. The condition for enzymatic hydrolysis of cellulose to generate glucose has been optimized in terms of reaction temperature, solution pH, types of cellulase and inorganic ions in order to obtain higher yields of glucose. To integrate the enzymatic catalysis and photocatalysis together, the glass fiber membrane with superior glucose penetration capability has been screened out. Lastly, the coupling of photocatalytic H2 production from water based on the Cu0.5Ni0.5 −TiO2 photocatalyst and enzymatic hydrolysis of cellulose has been quantitively evaluated in both mixed and membrane−separation systems. The membrane−separation system can avoid the depletion of cellulase activity induced by photocatalytic oxidation, and thus presents higher H2 production efficiencies with apparent quantum efficiency of 3.07 % at 365 ± 10 nm irradiation in initial 5 h. This work demonstrates that inorganic membrane integrated enzymatic catalysis and photocatalysis can be a powerful tool for different potential applications.

Apical microleakage in root canals with separated rotary instruments obturated with different endodontic sealers.

Aim:The aim of this study was to evaluate apical microleakage in root canals containing broken rotary instruments obturated with cold lateral condensation and thermoplasticized injectable gutta-percha, with different sealers, using glucose penetration leakage study.Materials and Methods:In this in vitro study, 96 extracted human mandibular premolars were decoronated, and the roots were randomly divided into eight groups (n = 12). Root canals were instrumented with #30 4% taper rotary files. The files were scratched 3 mm from the tip by a high-speed handpiece, and they were intentionally broken in the apical third of the canals. The middle and coronal sections of the canals were obturated by cold lateral condensation and thermoplasticized technique, using ZOE, resin, CaOH, and bioceramic sealers. Apical microleakage was measured using the glucose penetration method.Statistical Analysis:Independent Student's t-test and one-way ANOVA followed by Tukey's post hoc analysis were used for statistical analysis.Results:Bioceramic sealer group showed the least apical microleakage and this was then followed by the resin and CaOH groups demonstrating lesser apical microleakage and the highest microleakage was with the ZOE group. Mean apical microleakage scores between lateral and thermoplastic condensation techniques in each group were statistically significant (P < 0.001).Conclusion:Bioceramic sealer demonstrated the least apical leakage, whereas ZOE seal displayed the highest apical leakage.

Internal mass transfer considerations in biofilms of succinic acid producing Actinobacillus succinogenes

The rumen bacterium Actinobacillus succinogenes is reputable for its high productivity, -yield and -titre fermentative production of succinic acid under biofilm conditions. The paper presents an analysis of internal mass transfer effects in biofilm fermentations of A. succinogenes. Internal mass transfer effects were investigated by batch fermentations using attached- and resuspended biofilms as biocatalysts. In the latter, the biofilms were resuspended after initial development to simulate mass transfer free (free cell) fermentations. Intrinsic kinetics for succinic production obtained from resuspended free cell fermentations predicted faster production rates than for the attached biofilms runs (biofilm thicknesses in the range of 120–200 µm), indicating internal mass transfer restrictions. A developed biofilm reaction diffusion model gave good predictions of attached biofilm batch results by accounting for internal mass transfer in the biofilm. Biofilm effectiveness factors ranged from 75% to 97% for all batches at the inception of batch conditions but increased with progression of batch operation due to increased succinic acid titres which inhibited production rates. Biofilm thickness and succinic acid concentrations were shown to have a significant effect on internal mass transfer. A simplified algorithm was developed to estimate the pseudo-steady state glucose penetration and biofilm effectiveness of A. succinogenes biofilms without the requirement to solve the overall mass transfer model. The results clearly showed that internal mass transfer need to be considered in biofilm fermentations involving A succinogenes as high biomass concentrations may not always equate to increased productivities if mass transfer effects dominate.

Apical Sealing Ability of Different Endodontic Sealers Using Glucose Penetration Test: A Standardized Methodological Approach

Objectives: To compare the apical sealing ability of four endodontic sealers based on glucose penetration method and validate the uses of contralateral teeth to provide a well-balanced experimental group. Materials and methods: One-hundred-and-twenty (sixty pair) extracted contralateral lower premolars were selected and undergone strict radiographic protocol. Root canal anatomy of each pair contralateral teeth was matched buccolingually and mesiodistally according to inclusion criteria (single canal, mature apical foramen, canal type, canal width, length, and curvature). Matched-pair contralateral teeth were then reevaluated using CBCT and divided into right and left sides (n=60, each side). Next, all canals were instrumented up to size 30, taper 0.06. Subsequently, teeth were subdivided into five groups for each side and obturated with single cone gutta-percha (GP) and various sealers: Group 1 - GP only (control); Group 2 - EndoRez; Group 3 - Sealapex; Group 4 - EndoSeal MTA and Group 5 - BioRoot RCS. All samples were placed in an incubator at 37°C, 100% humidity for 72 hours. Four matched-pair teeth from each group were then subjected to thermocycling for 100 cycles, 1000 cycles and 10000 cycles, respectively. After that, they were decoronated, coated with three layers of nail varnish, and used for glucose penetration test. The concentrations of glucose (mmol/L) were measured after 24 hours. Data analyzed using One-way ANOVA complemented by post hoc Dunnett T3 Test and Paired sample T-Test. Results: EndoSeal MTA demonstrated statistically significant (p&amp;lt;0.05) lowest glucose penetration followed by BioRoot RCS, Sealapex, EndoRez, and lastly control group. Apical sealing ability decreased as the number of thermocycles increased. No significant difference (p&amp;gt;0.05) was found between matched-pair contralateral teeth. Conclusions: Bioceramic sealers demonstrated better sealing ability than resin and calcium hydroxide sealers. Using matched-pair contralateral teeth provided a well-balanced experimental group.

Effect of root canal wall moisture and filling techniques on the sealability of iRoot sp

To study the effect of root canal wall moisture and filling techniques on the sealability of iRoot sp. Sixty-two undamaged extracted human single-rooted teeth with fully developed apex were selected and prepared by crown-down technique. Two teeth were selected randomly to observe dentin tubules, opening, the residual teeth were randomly assigned to 3 groups: group A (wet), group B (slightly moist),group C(dry).The roots were further divided into 4 subgroups, group a: iRoot sp sealer without a core material (bulk-fill); group b: iRoot sp sealer with single cone obturation techniques; group c: iRoot sp sealer with heated gutta-purcha vertical pressure; group d: iRoot sp sealer with cold gutta-percha lateral compression technique. Glucose microleakage were measured in each group by glucose oxidase method. The differences in distribution of each group were analyzed with SPSS 19.0 software package. Group A and group B always showed the maximum and minimum amount of glucose penetration in the whole experimental process, and the difference was statistically significant at 28d (P<0.05). Under the same degree of moisture of root canal wall, glucose leakage of subgroup Aa was significantly higher than that of subgroup Ab and Ac at 15 d; and significantly higher than Ab, Ac, Ad at 21 d and 28 d(P<0.05). In group B and C, the subgroups a, b, c, d had no significant difference from each other during the experimental process(P>0.05). iRoot sp sealer has the best sealing effect when root canals were slightly moist. When the root canal wall is completely dry or slightly moist, the sealability of iRoot sp bulk-fill is similar to that of iRoot sp sealer with gutta-percha filling technique.

Influence of Iatrogenic Gaps, Cement Type, and Time on Microleakage of Cast Posts Using Spectrophotometer and Glucose Filtration Measurements.

To determine the influence of iatrogenic gaps, type of cement, and time on microleakage of cast posts using spectrophotometer and glucose filtration measurements. Forty-eight single-rooted teeth were divided into eight groups of six teeth each. Teeth were instrumented and obturated, and a cast post was fabricated. In addition to two control groups (positive and negative), a total of six groups were prepared: In four groups, an artificial 2- to 3-mm gap was created between post and residual gutta percha (GP), and two groups were prepared with intimate contact between post and residual GP. Posts were cemented with either zinc phosphate cement or resin cement. Leakage through the post after 1, 8, 14, and 20 days was measured using a glucose penetration model with two different reading methods. Mixed analysis of variance tests were performed to analyze the data. The presence of a gap between the apical end of the post and the most coronal portion of the GP remaining in the root canal after post space preparation increased microleakage significantly. However, microleakage was significantly less when the gap was refilled with GP compared to no gap. There was no difference in leakage between luting cements used. It was concluded that none of the cements were able to prevent microleakage. However, the addition of GP to residual GP did increase the sealing ability.

In-vitro model for assessing glucose diffusion through skin

Pig ear skin membrane-covered glucose biosensor based on oxygen electrode has been assessed as a tool to evaluate glucose penetration through skin in-vitro. For this, glucose oxidase (GOx) was immobilised on oxygen electrode and covered with the skin membrane. Exposing this electrode to the solution of glucose resulted in glucose penetration though skin membrane, its oxidation catalysed by GOx, consumption of O2 and decrease of the current of the oxygen electrode. By processing the biosensor responses to glucose, we found that glucose penetration through 250 µm thick skin membrane is slow; 90% of steady-state current response was reached in 32( ± 22) min. Apparent diffusion coefficient for glucose in skin was found to be equal to 0.15( ± 0.07)* 10−6 cm2 s−1. This value is 45 times lower than glucose diffusion coefficient in water. Tape-stripping of stratum corneum (SC) allows considerably faster glucose penetration. The electrodes covered with tape-stripped skin reached 90% of steady-state current response in 5.0(± 2.7) min. The theoretical estimate of glucose flux through SC was considered exploiting four-pathway theory of transdermal penetration. Theoretical flux values were more that three orders lower than measured experimentally. This high discrepancy might indicate that glucose penetration through healthy human skin could be even slower, allowing much lower flux, than it was found in our study for skin membranes from pig ears.

Effect of methods of evaluation on sealing ability of mineral trioxide aggregate apical plug

Aim:The purpose of the study was to evaluate and compare the sealing ability of mineral trioxide aggregate (MTA) with three different methods.Materials and Methods:Forty single canal teeth were decoronated, and root canals were enlarged to simulate immature apex. The samples were randomly divided into Group MD = MTA-angelus mixed with distilled water and Group MC = MTA-angelus mixed with 2% chlorhexidine, and apical seal was recorded with glucose penetration method, fluid filtration method, and dye penetration methods and compared.Results:The three methods of evaluation resulted differently. The glucose penetration method showed that MD sealed better than MC, but difference was statistically insignificant (P > 0.05). The fluid filtration method resulted that Group MC was statistically insignificant superior to Group MD (P > 0.05). The dye penetration method showed that Group MC sealed statistically better than Group MD.Conclusion:No correlation was found among the results obtained with the three methods of evaluation. Addition of chlorhexidine enhanced the sealing ability of MTA according to the fluid filtration test and dye leakage while according to the glucose penetration test, chlorhexidine did not enhance the sealing ability of MTA. This study showed that relying on the results of apical sealing by only method can be misleading.

Evaluating the quality of seal of root canals in the presence of separated rotary instrument when obturated with different obturation techniques using liquid photospectrometry

Introduction: Complete sealing of the root canal system is essential for the successful outcome of the endodontic treatment. unfortunately instrument may separate during biomechanical preparation and achieving a fluid tight seal may be difficult. Three dimensional obturation thus plays an important role in achievement of fluid tight in presence of separated rotary instruments. To evaluate the quality of seal of root canals in the presence of separated rotary instrument when obturated with different obturation techniques using liquid photospectrometry. Materials and Methods: One hundred and twenty freshly extracted mandibular human premolars with straight and single root canal were selected. The preparations of canal were completed by single file system with primary file size 25/08 (WaveOne system, Dentsply Maillefer, Switzerland). The roots were randomly assigned into two groups: Group I (n = 60) and Group II (n = 60). Group I (n = 60) was subdivided into three subgroups A, B, and C. Group A (n = 20): Roots were obturated with lateral condensation technique without sealer placement and without instrument being separated at apical third. Group B (n = 20): Roots were obturated with lateral compaction technique using epoxy resin based sealer (AH Plus) placed in canals without instrument being separated at apical third. Group C (n = 20): Roots were obturated with lateral compaction technique using epoxy resin-based sealer (AH Plus) placed along the root canals with instrument being separated at apical third. Group II (n = 60) was also subdivided into three subgroups A, B, and C with twenty roots in each subgroup. In subgroups A, B, and C of Group II, the same methodology was used, except obturation was done using thermoplasticized Gutta-percha (Calamus, Dentsply Maillefer, Switzerland). The modified glucose penetration setup was used and samples were then analyzed with a spectrophotometer (ELICO SL 244-double beam ultraviolet-visible) at 340 nm wavelength. Statistical analysis was done using descriptive and inferential statistics using Student's paired and unpaired t-test and softwares used in the analysis were SPSS 17.0 version and GraphPad Prism 5.0 version and P Results: Significant variation was found in mean glucose leakage in groups obturated with lateral condensation and thermoplasticized Gutta-percha (t = 2.10, P = 0.042). Conclusions: Leakage observed with thermoplasticized obturation was less when compared to lateral condensation. Three-dimensional obturation plays a crucial role than the separated instrument during endodontic therapy.

EVALUATION OF TWO DIFFERENT MATERIALS FOR PRE-ENDODONTIC RESTORATION OF BADLY DESTRUCTED TEETH

Abstract: Introduction: Pulpal and periradicular diseases develop when microorganisms and/or their by-products contaminate these tissues. Therefore, the major goal of endodontic restoration is to prevent the penetration of microorganisms into the coronal pulpal space and root canal system. Objectives: To evaluate and compare the sealing ability of two intermediate temporary filling materials in badly destructed teeth reinforced with stainless steel bands and to evaluate the adaptation of these materials upon application of clamps and rubber dam material. Materials and methods: 65 mature maxillary premolar teeth were used in this study. This study was divided in two parts. Part I: evaluation of coronal leakage by glucose penetration model and spectrophotometer. Teeth were randomly divided into two experimental groups (n=10) and a control group (n=15). Access cavities and stimulation of loss of tooth structure were done. Instrumentation till apical size # 35 and reinforcement with stainless steel bands were done. Group I: teeth were filled with Cavit-G (3M ESPE, Seefeld, Germany); Group II: teeth were filled with CLIP (Voco, Cuxhaven, Germany); Group III: used as positive and negative control group. Measurement of coronal leakage was performed at the 3rd, 7th and 15th day. Part II: evaluation of adaptation of coronal restoration by using 2.5x magnifying loupes and USPHS criteria, grouping was done as before but ten teeth were used as positive controls. Results: Part I; CLIP (group II) showed the least glucose leakage with median change of leakage (1052.45) mg/dl followed by Cavit-G (Group I) with median change of (2828.55) mg/dl. The difference was statistically significant (P= 0.001). In part II; results were statistically significant (p=0.001), where the CLIP group showed better adaptation than Cavit-G group. Conclusions: CLIP seals against marginal leakage better than Cavit-G. CLIP provides better adaptation than Cavit-G on application of clamps and rubber dam. Keywords: Endodontics, temporary filling materials, coronal leakage, Cavit-G, CLIP.

Quantitative microleakage analysis of root canal filling materials in single-rooted canals.

The purpose of this study was to analyze the sealing ability of different root canal filling materials over a 6-week period using a glucose penetration model. Forty-six recently extracted human premolars were used in this study. The root canals were enlarged to 40/0.06. Prepared canals were randomly assigned into four groups (n = 10) as follows: Group 1, Gutta-Percha (GP)/AH Plus with cold lateral compaction; Group 2, GP/AH Plus with continuous wave compaction; Group 3, RealSeal SE obturation system; and Group 4, OrthoMTA. The remaining specimens were used as positive and negative controls, and all specimens underwent thermocycling (10,000; 5-55 °C). The sealing ability of all samples was evaluated at 24 h, 1, 2, 4, and 6 weeks using a quantitative glucose leakage model, and scanning electron microscope (SEM) images were taken. A mixed effect analysis using R statistical language was performed. Groups 1, 2, and 4 showed low leakage levels during experimental periods. Group 3 showed low leakage levels for the first 2 weeks; however, the leakage level was significantly increased after 2 weeks compared to negative control group (p < 0.05). In the SEM results, Group 3 showed imperfect dentin bonding, whereas Group 4 showed calcium silicate hydrate short tags, which are formed at the access of the dentin tubules. GP/AH Plus and OrthoMTA showed less microleakage than RealSeal SE obturation system when used as root canal filling materials. Traditional GP/AH Plus sealer and the newly developed OrthoMTA are more appropriate for ideal sealing of the root canals.

Quantitative microleakage analysis of endodontic temporary filling materials using a glucose penetration model

Objective. The purpose of this study was to analyze the sealing ability of different temporary endodontic materials over a 6-week period using a glucose penetration model. Materials and methods. Standardized holes were formed on 48 dentin discs from human premolars. The thicknesses of the specimens were distributed evenly to 2 mm, 3 mm and 4 mm. Prepared dentin specimens were randomly assigned into six groups (n = 7) and the holes in the dentin specimens were filled with two kinds of temporary filling materials as per the manufacturers’ instructions as follows: Caviton (GC Corporation, Tokyo, Japan) 2 mm, 3 mm, 4 mm and IRM (Dentsply International Inc., Milford, DE) 2 mm, 3 mm, 4 mm. The remaining specimens were used as positive and negative controls and all specimens underwent thermocycling (1000; 5–55°C). The sealing ability of all samples was evaluated using the leakage model for glucose. The samples were analyzed by a spectrophotometer in quantitative glucose microleakage test over a period of 6 weeks. As a statistical inference, a mixed effect analysis was applied to analyze serial measurements over time. Results. The Caviton groups showed less glucose penetration in comparison with the IRM groups. The Caviton 4 mm group demonstrated relatively low glucose leakage over the test period. High glucose leakage was detected throughout the test period in all IRM groups. The glucose leakage level increased after 1 week in the Caviton 2 mm group and after 4 weeks in the Caviton 3 mm and 4 mm groups (p < 0.05). Conclusions. Caviton had better sealing ability than IRM in the glucose penetration model during 6 weeks. Temporary filling of Caviton to at least 3 mm in thickness is necessary and temporary filling periods should not exceed 4 weeks.

Effects of ultrasonic root-end cavity preparation with different surgical-tips and at different power-settings on glucose-leakage of root-end filling material

Aim:The aim of this in vitro study was to evaluate the effects of different ultrasonic surgical-tips and power-settings on micro-leakage of root-end filling material.Materials and Methods:The root canals were instrumented using rotary-files and were filled with tapered gutta-percha and root canal sealer using a single-cone technique. The apical 3 mm of each root was resected and the roots were divided into six experimental groups; negative and positive control groups. Root-end cavities were prepared with diamond-coated, zirconum-nitride-coated and stainless-steel ultrasonic retro-tips at half-power and high-power settings. The time required to prepare the root-end cavities for each group was recorded. Root-end cavities were filled with Super-EBA. Leakage values of all samples evaluated with glucose penetration method on 7, 14, 21 and 28th days. The results were statistically analyzed with Kruskal-Wallis and Hollander-Wolfe tests.Results:The mean time required to prepare retro cavities using diamond-coated surgical tip at high-power setting was significantly less than other groups (P < 0.01). There were no statistically significant differences in the glucose penetration between the groups at first and second weeks (P > 0.01). Diamond-coated surgical tip showed the least leakage at high-power setting at 3rd and 4th weeks (P < 0.01).Conclusions:Under the conditions of this study, cavity preparation time was the shortest and the leakage of the root-end filling was the least when diamond-coated retro-tip used at high-power setting.

Impact of root canal preparation size and taper on coronal-apical micro-leakage using glucose penetration method.

Objectives: The purpose of this in vitro study was to assess the effect of root canal preparation size and taper on the amounts of glucose penetration. Material and Methods: For conducting this experimental study, eighty mandibular premolars with single straight canals were divided randomly into 2 experimental groups of 30 samples each and 2 control groups. Using K-files and the balance force technique, canals in group 1 were prepared apically to size 25 and coronally to size 2 Peesoreamer. Group 2 were instrumented apically and coronally to size 40 and size 6 Peesoreamer, respectively. Rotary instrumentation was accomplished in group 1; using size 25 and .04 tapered and in group 2, size 35 and .06 tapered Flex Master files. Canals were then obturated by lateral compaction of cold gutta-percha. Glucose penetration through root canal fillings was measured at 1, 8, 15, 22 and 30 days. Data were recorded as mmol/L and statistically analyzed with Mann-Whitney U test (P value=. 05). Results: In comparison to group 1, group 2 showed significant glucose leakage during the experimental period (P value < .0001). Also, in each experimental group, the amount of micro-leakage was significantly increased at the end of the study. Conclusions: Under the condition of this study, the amounts of micro-leakage through root canal fillings are directly related to the size and taper of root canal preparation and reducing the preparation size may lead to less micro-leakage. Key words:Dental leakage, root canal preparation, endodontics.

Similar Sealability Between Bioceramic Putty Ready-To-Use Repair Cement and White MTA

This study was designed to assess the ability to prevent glucose penetration of a bioceramic putty ready-to-use repair cement comparing to white mineral trioxide aggregate (WMTA). After root canal instrumentation, the apical 3 mm of maxillary incisors were resected and root-end cavities with depth of 3 mm were prepared with ultrasound and filled with the tested materials (15 roots per group). All roots were mounted in a double chamber system to assess glucose penetration using 15 psi pressure application. After 1 h, glucose concentrations in the lower chamber were measured following an enzymatic reaction. Four roots were used as controls. The Mann-Whitney test verified differences in glucose leakage between groups and the Tukey's test was used for multiple comparisons. Significance level was set at 5%. There was no significant difference in glucose leakage between iRoot BP Plus and White MTA groups. iRoot BP Plus had a similar ability to that of white MTA in preventing glucose leakage as a root-end filling material.

In vitro comparative evaluation of sealing ability of root canal sealers using glucose penetration test

In vitro comparative evaluation of sealing ability of root canal sealers using glucose penetration test

Lack of correlation between sealer penetration into dentinal tubules and sealability in nonbonded root fillings

To determine the correlation between leakage and sealer penetration into dentinal tubule. The root canal of 60 mandibular central incisor teeth were prepared and filled under standardized conditions. Teeth were placed into a device to assess glucose penetration using 15 psi pressure application. After 1 h, glucose concentrations in the lower chamber were measured using an enzymatic reaction. Each specimen was then sectioned horizontally at 3, 6 and 8 mm from the apex, and a standard metallographic preparation was performed. The coronally facing surface of each slice was examined in a high-resolution stereomicroscope and under Confocal Laser Scanning Microscope. For each slice, the external outline of the root canal, the internal circumference of the root canal walls and the areas along the canal walls where the sealer had penetrated into the dentinal tubules (sealer tags) were outlined and measured. Afterwards, the percentage of the sealer penetration in each section was calculated. The Spearman correlation test was used to verify the correlation between the variables studied (glucose leakage and sealer penetration into dentinal tubules). The means and standard deviations of glucose leakage were 0.744 g L(-1) (±0.5), and the percentage of the dentinal tubule sealer penetration varied between teeth from 5.6% to 42.21%, with an average of 13.7 ± 17.2%. The Spearman correlation test revealed no significant correlation between the two factors analysed (P = 0.082). The r(2) value was equal to 0.12. There was no significant correlation between sealability sealer penetration into dentinal tubules. The lack of correlation reported is of relevance as sealer penetration into dentinal tubules has been used as an advantageous property during the launch of new root filling materials and techniques.

Comparative evaluation of sealing properties of different obturation systems placed over apically fractured rotary NiTi files

Aim:To evaluate sealing properties of different obturation systems placed over apically fractured rotary NiTi files.Materials and Methods:Forty freshly extracted human mandibular premolars were prepared by using Protaper (Dentsply-Maillefer, Ballaigues, Switzerland) or the RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) systems (n=20 for each), after which half of the specimens were subjected to instrument separation at the apical level. Roots with and without apically separated instruments (n=5) were filled with the two obturation systems i.e. Thermafil and lateral compaction technique. The modified glucose penetration setup was used to assess the microleakage. The leakage data was statistically analyzed.Results:The amount of leakage was significantly lower in specimens containing fractured instruments, regardless of the obturation method used. Roots obturated with Thermafil displayed significantly less leakage than cold lateral compaction technique, both, in the presence and absence of separated instruments. There was no significant difference among specimens prepared with ProTaper and RaCe when Thermafil obturation was done. But with cold lateral compaction technique, RaCe system showed less leakage as compared to ProTaper system.Conclusion:The type of obturation may play more important role than the type of instrument or retained/non-retained instrument factor.

Coronal microleakage of four temporary restorative materials in Class II-type endodontic access preparations

Objectives: The purpose of this study was to evaluate the microleakage of 4 temporary materials in teeth with Class II-type endodontic access preparations by using a glucose penetration model. Materials and Methods: Glucose reaction test was performed to rule out the presence of any reaction between glucose and temporary material. Class II-type endodontic access preparations were made in extracted human premolars with a single root (n = 10). Each experimental group was restored with Caviton (GC), Spacer (Vericom), IRM (Dentsply-Caulk), or Fuji II(GC). Microleakage of four materials used as temporary restorative materials was evaluated by using a glucose penetration model. Data were analyzed by the one-way analysis of variance followed by a multiplecomparison Tukey test. The interface between materials and tooth were examined under a scanning electron microscope (SEM). Results: There was no significant reaction between glucose and temporary materials used in this study. Microleakage was significantly lower for Caviton and Spacer than for Fuji II and IRM. SEM observation showed more intimate adaptation of tooth-restoration interfaces in Caviton and Spacer than in IRM and Fuji II. Conclusions: Compared to IRM and Fuji II, Caviton and Spacer can be considered better temporary sealing materials in Class II-type endodontic access cavities.

Comparison of the root-end seal provided by bioceramic repair cements and White MTA

To compare the ability of Ceramicrete, BioAggregate and white ProRoot MTA (mineral trioxide aggregate) to prevent glucose leakage through root-end fillings. After root canal instrumentation, the apical 3 mm of maxillary incisors were resected and retropreparations, 3 mm in depth, were created with ultrasound. Root-end cavities were filled with the tested materials (15 roots per group). All roots were mounted in a double-chamber system to assess glucose penetration using 15 psi pressure application. After 1 h, glucose concentrations in the lower chamber were measured following an enzymatic reaction. Four roots were used as controls. One-way anova verified differences in glucose leakage between groups and Tukey test performed multiple comparisons. Significance was set at α = 5%. There was a significant difference between the three materials (anova, P < 0.05). Ceramicrete had significantly lower glucose penetration than BioAggregate (Tukey, P < 0.05). There was no difference between the two bioceramic cements and white MTA (P > 0.05). Both endodontic bioceramic repair cements displayed similar leakage results to white MTA when used as root-end fillings materials. Ceramicrete had significantly lower glucose penetration.