Effect of three different conditioning agents on cavosurface microleakage and bond strength of glass ionomer restorations – An in vitro study

Aim: This study aimed to investigate the conditioning effects of phosphoric acid/5.25% sodium hypochlorite (NaOCl) mixture, 2% chlorhexidine (CHX) digluconate, and 10% polyacrylic acid on cavosurface microleakage and bond strength of glass ionomer (GI) restorations. Materials and Methods: Out of 68 extracted premolars, 34 teeth were selected for microleakage and 34 for bond strength evaluation. The samples were divided into the following four groups. Group 1: pretreatment with 50/50 volume% mixture of 5.25% NaOCl solution and 37% phosphoric acid (H3PO4), Group 2:pretreatment with 2% CHX digluconate, Group 3: pretreatment with 10% polyacrylic acid (positive control), and Group 4: no pretreatment (negative control). All the samples were then restored with glass ionomer cement (GIC). Microleakage was evaluated using a stereomicroscope and rhodamine-B dye penetration test. For bond strength, flat dentin surface was exposed and pretreated as mentioned previously and restored with GIC and was evaluated using universal testing machine. Results: Among all the four groups, Group 1 showed least microleakage and highest bond strength when compared with other groups. Whereas the Group 4 samples which were not pretreated with any of the conditioning agent showed the least shear bond strength with greatest cavosurface microleakage when compared to the groups which were pretreated with the conditioning agents. Conclusions: A combination of 50/50 volume % mixture of 37% H3PO4 and 5.25% NaOCl can be a good choice for surface pretreatment of GI restorations.

A comparison of apical sealing ability of different root canal obturation techniques in oval root canals / 口腔疾病防治

Objective@# To investigate the effect of different root canal obturation techniques on apical sealing in oval root canals. @*Methods@#120 recently extracted human premolars with single oval canal were randomly divided into 6 groups, including single point obturation, warm gutta percha vertical condensation, cold lateral condensation obturation method combined with different root canal sealers (iRoot SP or AH-Plus). There're six groups in total, including single point iRoot group, warm gutta percha iRoot group, cold gutta percha iRoot group, single point AH group, warm gutta percha AH group, cold gutta percha AH group. @*Results @#Root depth of dye penetration in warm gutta percha iRoot group and warm gutta percha AH group were significantly lower than group single point iRoot group and single point AH group (P < 0.05), and root depth of dye penetration of warm gutta percha iRoot group, cold gutta percha iRoot group was less than warm gutta percha AH group, cold gutta percha group (P < 0.05), but there was no statistic difference between other groups (P > 0.05). @*Conclusion @#In root canal treatment, warm gutta-percha condensation technology can make the oval canal root achieve better sealing effect, using iRoot SP is better than using AH-Plus.

Microleakage of Different Thickness of Restorative Materials Used in Endodontically Treated Teeth by Dye Penetration

@#This study aimedto evaluate the coronal microleakage of different thickness of different restorative materials (glass ionomer cement (GIC, GC Gold Label 2), composite restoration (SDR, Dentsply Sirona) and (Filtek Z350 XT, 3M ESPE)) used as final restoration in endodontically treated teeth. 72 sound maxillary incisors were used. Following instrumentation, all canals were obturated with gutta-percha (Dentsply Maillefer) and Roth sealer (Roth International Ltd). After 2mm of gutta-percha removal below cemento-enamel junction, the crown was cut until length of 6mm from the gutta-percha to the incisal edge was achieved. The teeth were divided into four experimental groups (n=18) and access restorations were placed in different thickness combinations. Group 1 (G1): 2mm SDR + 4mm Filtek; Group 2 (G2): 4mm SDR + 2mm Filtek; Group 3 (G3): 2mm GIC + 2mm SDR + 2mm Filtek; Group 4 G4): 6mm SDR. All samples were thermocycled (500 thermal cycles between 5o and 55oC and dwell time of 30s), coated with nail varnish leaving 1mm margin around the filling material, immersed in 2% Rhodamine B solution and sectioned longitudinally. The dye penetration was observed under a stereomicroscope (Olympus SZX7) with 1.25x magnification. The data were analysed using Kolmogorov-Smirnov test, ANOVA test and post-hoc Tukey’s HSD test.There was significant difference of microleakage among all groups. G1 showed least microleakage but with no significant difference between G1 and G3 (p=0.513) and G1 and G4 (p=0.477). G2 showed significant microleakage compared to G1, G3 and G4 (p<0.05). In conclusion, sandwich technique between SDR and Filtek reduces microleakage in which the combination of 2mm SDR with 4mm Filtek in G1 had the least microleakage but with additional 2mm of GIC in G3 further reduces the microleakage.

Evaluation of the leakage of bleaching materials through different bases into the root canal filling: an invitro study

AIM: The purpose of this study was to evaluate the leakage of bleaching agents through 3 different bases into the obturated pulp space and dentinal tubules in intra coronal bleaching. MATERIAL AND METHODS: Fifty-five freshly extracted, intact non-carious single rooted teeth were collected and stored in formalin until used. The specimen divided into experimental and control group. Experimental group were further subdivided into 3 subgroups on the base of cervical base materials. Group I was Type II GIC, Group II was Fuji II LC and Group III was Hybrid composite. The control groups was divides into negative group (received the bleaching agent and received complete external coating including access cavity) and positive control group (did not receive any external coating). The obturated pulp space were removed at a level of 3 mm below the cemento enamel junction and filled with dry cotton pellets and temporized with temporary cement, stored at ± 37°C and 100% relative humidity for five days, the bleaching material were placed in the pulp chamber (a paste of sodium perborate i.e. 0.15g and 30% hydrogen peroxide 0.05ml), and then stored for 3 days in an incubator. Later on the teeth were immersed in India ink dye and stored at ± 37°C and 100% relative humidity for 5 days. Specimens were examined under binocular microscope with a stage micrometer to analyze the degree of dye penetration. RESULTS: The minimal leakage values were observed with type II glass ionomer cement followed by light cure glass ionomer cement and lastly by hybrid composite. CONCLUSION: The present invitro investigation evaluated the microleakage observed with different cervical base materials during non-vital bleaching procedures.

Sealing ability of different versions of GuttaFlow2 in comparison to GuttaFlow and AH Plus

Introduction and objective: GuttaFlow2 is a further development of the silicone sealer GuttaFlow, exhibiting a stiffer consistency. This is intended to overcome possible problems regarding retention of the apical part of the root canal filling when preparing for a fiber post. GuttaFlow2 is delivered within a capsule, like GuttaFlow, or within an automix syringe. This study compared apical dye leakage of GuttaFlow2 in comparison to GuttaFlow and AH Plus. The null hypothesis tested was that different sealers exhibited similar microleakage. Material and methods: Seventy extracted human lower premolars with fully mature apices were root canal prepared to 45/.04 and divided into seven groups: group 1: AH Plus sealer, group 2: "normal" setting GuttaFlow, group 3: "fast" setting GuttaFlow, group 4: GuttaFlow2 within a capsule, group 5: GuttaFlow2 within an automix syringe, group 6: positive control, group 7: negative control (n = 10 each). Root canals were filled with sealer (except group 7) and a master gutta-percha cone size 40/.04 using the non-compaction technique. A dye penetration test was carried out by centrifugation for 3 min at 30 G within 5 % methylene blue dye. Linear dye penetration was recorded. Statistical evaluation was carried out with IBM SPSS 19.0 (α = 0.05). Results: The positive control was significantly different from all other groups (ANOVA, p < 0.001; Student-Newman-Keuls post-hoc test p < 0.05). When the control groups were disregarded, no significant differences were apparent. Groups 1 to 5 showed low leakage values when compared with results of earlier studies using a similar methodology. Conclusion: All sealers tested exhibited low dye leakage values.

Comparing the sealing properties of mineral trioxide aggregate and an experimental ceramic based root end filling material in different environments.

Background: An apical seal is an important factor in achieving success in surgical endodontics. Aim: The purpose of this study was to compare the sealing properties of mineral trioxide aggregate (MTA) with a new ceramic based root end filling material (Cold Ceramic) in different environments. Materials and Methods: One hundred teeth were selected. The root canals were instrumented and obturated. Except for the apical 2 mm, the root surfaces were sealed. After root resection, 3 mm depth root-end cavities were prepared. For each material, roots were divided into 3 equal subgroups and the root-end filling was done in different environments (dry, saliva contaminated, blood contaminated). Five roots served as positive and 5 roots as negative controls. Samples were immersed in 2% methylene blue dye. Roots were sectioned longitudinally and examined under stereomicroscope to record the extension of dye penetration. Results: All experimental groups demonstrated dye penetration. The lowest linear leakage was seen in Cold Ceramic blood contaminated group while the highest leakage was observed in MTA blood contaminated group. The linear dye penetration of both MTA and Cold Ceramic (CC) groups did not show any significant differences among different environments. Also, the difference between MTA and CC was not significant in dry and saliva contaminated subgroups. Only the difference between dye penetration of MTA and CC in blood contaminated subgroups showed significant difference ( P = 0.008). Conclusion: The sealing property of this ceramic based root end filling material (Cold Ceramic) is better than MTA in blood contaminated condition and at least similar to MTA in other conditions.

Secondary protective seal of root canal fillings performed under simulated clinical conditions

Objective: This study evaluated sealing properties of root canal fillings with an additional composite barrier. The null hypothesis tested was that different sealers and different methods of sealer removal did not influence microleakage. Material and methods: Eighty extracted human molars with fully mature apices had root canal prepared to size 60 taper .02 and divided into eight groups: three experimental groups for each sealer and negative/positive control (n = 10 each). Teeth of experimental groups were mounted into the molar region of a training puppet to simulate clinical conditions. Root canals were filled with AH Plus or GuttaFlow and gutta-percha. Excess sealer was removed with: ethanol-moistened foam pellet only, additional preparation with a water-cooled diamond bur or additional etch-and-rinse procedure (37% phosphoric acid gel). All procedures were carried out until clean as judged by the naked eye. In all groups except the positive control Syntac was applied to the access cavity. Tetric flow was applied in two increments of 1 mm each. A dye penetration test was carried out by centrifugation for 3 min at 30 G within 5% methylene blue dye. Statistical evaluation was carried out with PASW 18.0 (α = 0.05). Results: Although the two sealers had different chemical composition, sealer exhibited no influence on the results, whereas technique of sealer removal did (Two-way-ANOVA, p < 0.001). Groups with "foam pellet" or "bur preparation" showed significantly more leakage than groups with "etch-and rinse" (SNK, p < 0.05). Conclusion: Applying an etch-and-rinse procedure prior to Syntac may be beneficial for the adhesive seal over root canal fillings.

Microleakage of resilon: Effects of several self-etching primer / 대한치과보존학회지

The purpose of this study was to compare the apical microleakage in root canal filled with Resilon by several self-etching primers and methacrylate-based root canal sealer. Seventy single-rooted human teeth were used in this study. The canals were instrumented by a crown-down manner with Gate-Glidden drills and .04 Taper Profile to ISO #40. The teeth were randomly divided into four experimental groups of 15 teeth each according to root canal filling material and self-etching primers and two control groups (positive and negative) of 5 teeth each as follows: group 1 - gutta percha and AH26(R) sealer; group 2 - Resilon, RealSeal(TM) primer and RealSeal(TM) sealer; group 3 - Resilon, Clearfil SE Bond(R) primer and RealSeal(TM) sealer group 4 - Resilon, AdheSe(R) primer and RealSeal(TM) sealer. Apical leakage was measured by a maximum length of linear dye penetration of roots sectioned longitudinally by diamond disk. Statistical analysis was performed using the One-way ANOVA followed by Scheffe's test. There were no statistical differences in the mean apical dye penetration among the groups 2, 3 and 4 of self-etching primers. And group 1, 2 and 3 had also no statistical difference in apical dye penetration. But, there was statistical difference between group 1 and 4 (p < 0.05). The group 1 showed the least dye penetration. According to the results of this study, Resilon with self-etching primer was not sealed root canal better than gutta precha with AH26(R) at sealing root canals. And there was no significant difference in apical leakage among the three self-etching primers.

Estimation of relation between techniques of dye penetration for microleakage and SEM evaluation for marginal adaptation of the restoration / 대한치과보존학회지

The purpose of this study was to estimate the relation between techniques used for microleakage from dye penetration and for marginal adaptation from SEM evaluation of the restoration. Using high speed #330 bur, class V cavities (4 x 3 x 1.5 mm around CEJ) were prepared on the buccal surface of 20 extracted human molars. Six dimples as reference points for SEM and dye penetration evaluation were made with 1/2 round bur. Cavity was bulk filled with microhybrid composite resin (Esthet X) and all-in-one adhesive (Xeno III). Teeth were stored in saline solution for one day, after then, they were finished and polished using Sof-Lex system. Fifty percent silver nitrate dye solution was used for the evaluation of microleakage and resin replica was used for marginal adaptation. All of these were done after 1000 times thermocycling between 5 and 55degrees C. Vertical sections were made through three dimples of restoration to obtain samples for the evaluation of dye penetration and inner marginal adaptation. Outer adaptational estimation was done with an intact restoration before sectioning. Dye penetration was determined in three degrees and percentage of outer and inner leaky margin was estimated from SEM image. The data were analysed statistically: Spearman's rho test were used to check relationships between two methods. The result were as follows: 1. There were significant relationships between degree of dye penetration and inner and outer marginal adaptations each (p < 0.01). 2. However, there was no significant relationship between the results of inner and outer marginal adaptation. Within the results of this study, relationship between the percentage of marginal adaptation and microleakage shows significant relationship. However, inner and outer marginal adaptation did not show any significant relationship mutually.

Marginal microleakage of single step adhesives / 대한치과보존학회지

This study evaluated the marginal microleakage of five single step adhesives. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on both buccal and lingual surfaces of extracted human molar teeth. Prepared teeth were randomly divided into five groups and restored using one of the single step adhesives and composite resins: Prompt L-Pop/Filtek Z-250 (Group 1), AQ Bond/Metafil CX (Group 2), One-Up Bond F/Palfique Toughwell (Group 3), Futurabond/Admira (Group 4), Xeno III/Spectrum TPH (Group 5). The restored teeth were thermocycled. Microleakage was assessed by dye penetration using 2% methylene blue dye solution. The teeth were bisected buccolingually and evaluated for microleakage under steromicroscope. The data were statistically analysed by Kruskal-Wallis test and Mann-Whitney tests. The results of this study were as follows; 1. Microleakage of enamel margins in group 3 was statistically higher than that in groups 1, 2, 4, 5 (p < 0.05). 2. Microleakage of dentin margins in group 1 was statistically higher than that in groups 2, 5, and that in group 3 was statistically higher than that in groups 2, 4, 5 (p < 0.05). 3. Dentin marginal microleakage was higher than enamel marginal microleakage in all experimental groups. In conclusion, Prompt L-Pop showed the least leakage at enamel margin, and AQ Bond showed at dentin margin in this study. Marginal miroleakage in dentin was higher than that in enamel.

The effect of calcium hydroxide removal and the seal ability of root canal using different irrigation methods / 实用口腔医学杂志

Objective:To evaluate the ability of calcium hydroxide removal using different irrigation methods and the effect on canal sealing.Methods:200 human single root canal premolar teeth were prepared.Divided the teeth randomly into 2 groups(each group 96 teeth,8 as control),one group filled with chemical calcium hydroxide and another filled with finished product calcium hydroxide.7 days after,divided each groups randomly into 6 subsets and remove the calcium hydroxide in the root canal(table1).Then each subset group choose 8 teeth randomly,observed by scanning electron microscope.Other specimens were obturated by lateral condensation of cold gutta-percha with a AH-Plus sealer,stained by Indian ink and then made into transparent teeth model.Results:At the same condition,there was no significant difference between group A and group B;the results of groups associated with ultrasonic were better than groups with injection syringe.The rinse solution EDTA was the best,distilled water was the worse.Dye penetration showed that the length of dye staining was no significant difference among all groups.Conclusion:Ultrasonic and sodium hypochlorite associate EDTA is the best method to remove the calcium hydroxide.But none of the methods and rinse solution used in this experiment can remove all of the calcium hydroxide.The calcium hydroxide remained influence on the root canal sealer is not predominance.