The effect of smear layer on bacterial penetration through roots obturated using zinc oxide eugenol-based sealer.

BACKGROUND: Smear layer removal has been shown to reduce bacterial penetration through root canal obturations when resin-based endodontic sealer is used. The purpose of this in vitro study was to test this effect when a non-resin-based sealer is used. MATERIAL AND METHODS: Thirty root segments were assigned to the following groups: Smear layer removed (n = 8); smear layer retained (n = 8); negative controls (n = 10; 5 with smear layer, 5 without); and positive controls (n = 4; 2 with smear layer, 2 without). After rotary instrumentation, smear layers were removed in the treatment group and half of controls using 17% ethylenediamenetetraacetic acid (EDTA) prior to obturation. Each obturated root was affixed into a dual-chamber leakage model employing Streptococcus mutans. Roots were incubated at 37 °C for 120 d. Days until lower chamber turbidity occurred was recorded for each sample, and data were analyzed using Kaplan-Meier survival curve analysis (p = 0.05). RESULTS: No negative controls leaked, while all positive controls were turbid within 1 day. Mean days to leakage for roots with smear layer intact was 82.75 (+/- 33.29, 95% CI), although three never leaked. Mean days to leakage through roots with smear layer removed was 46.25 (+/- 26.67, 95% CI), and all leaked. Treatment survival curves were significantly different (p = 0.048). CONCLUSIONS: Under the conditions and limitations of this study, retaining the smear layer reduced the rate of bacterial penetration through canals which had been obturated using zinc oxide eugenol (ZOE) -based sealer.

The effect of smear layer removal on E. faecalis leakage and bond strength of four resin-based root canal sealers.

BACKGROUND: The aim of the study was to assess bacterial sealability and bonding ability of methacrylate-based Resilon (RS, SybronEndo), Endo Rez (ER, Ultradent Products Inc), and epoxy-based AH Plus (AH, Dentsply/DeTrey), MTA Fill Apex (MTAF, Angelus Soluções Odontológicas) root canal sealers, and the effect of the smear layer removal on the sealability. METHODS: One hundred thirty root segments were instrumented up to apical size #60 and rinsed with 2.5% NaOCl. Half of the roots were rinsed with 5ml 17% EDTA to remove the smear layer. All the roots were filled with AH, ER, MTAF sealers and gutta-percha, or RS with Resilon cones. After storage at 37°C for 7 days the samples were mounted into bacterial leakage assay for 50 days. Another 100 roots were instrumented and rinsed as described above, split longitudinally, cut into the cervical, middle and apical parts. The sealers were injected through the plastic mould on the dentin surface. After 7 days of incubation at 37°C, bond strength was tested using a notched-edge test fixture (Crosshead, Ultradent Products Inc.) and a universal testing machine (Lloyd Instruments). RESULTS: AH revealed the longest mean time for bacterial resistance by 29.4 and 36.8 days (with and without smear layer, respectively) followed by RS (15.1 and 24.7 days, respectively). The difference between materials was significant (p<0.001). Bond strength values ranged from 0.2± 0.1 to 3.5± 0.7 MPa and increased from the apical to the cervical third. In the apical third, AH showed the highest mean (SD) bond values 1.4 (0.4) MPa and 1.7 (0.6) MPa (with and without smear, respectively, followed by RS, 0.5 (0.1) MPa and 0.8 (0.1) MPa, respectively. The difference between materials was significant (p=0.001). CONCLUSION: The effect of the smear layer removal on the sealability was material-dependent.

Comparison of Er,Cr:YSGG Laser Handpieces for Class II Preparation and Microleakage of Silorane- or Methacrylate-Based Composite Restorations.

OBJECTIVE: The aim of this study was to evaluate the influence of cavity preparation with different Er,Cr:YSGG laser handpieces on microleakage of different posterior composite restorations. METHODS: Fifty-four extracted intact human premolars were randomly assigned to three groups according to cavity preparation method: Bur Group: high-speed diamond bur (Diatech), MD Group: Er,Cr:YSGG laser Waterlase MD handpiece (Biolase Millennium II), and Turbo Group: Er,Cr:YSGG laser Waterlase MD TURBO handpiece (Biolase Millennium II). One hundred eight Class II slot cavities were prepared on the mesial and distal proximal surfaces of each tooth, and the cavity preparation times required were determined. The groups were then subdivided according to the restorative systems used (n = 12): a conventional methacrylate-based microhybrid composite (Filtek P60+Adper Single Bond 2/3M); a silorane-based resin composite (Filtek Silorane+Silorane System Adhesive/3M); and a nanohybrid methacrylate-based composite (Kalore+G-Bond/GC). The restorative systems were applied according to the manufacturers' recommendations. Following thermocycling (X5000; 5°C-55°C), the teeth were coated with nail varnish except the restoration margins, immersed in 0.5% basic fuchsin dye solution, and sectioned in a mesiodistal direction. Dye penetration was evaluated under a light microscope for occlusal and cervical margins. Data were analyzed with one-way ANOVA and chi-square tests (p < 0.05). RESULTS: The cavity preparation time (mean ± SD) required for Bur, MD, and Turbo group was 31.25 ± 3.82, 222.94 ± 15.85, and 92.5 ± 7.42 sec, respectively, and the differences among the groups were statistically significant (p < 0.05). Comparing the occlusal and cervical microleakage scores, no statistically significant differences were found among the groups and subgroups (p > 0.05). CONCLUSIONS: Er;Cr:YSGG laser cavity preparation with the Turbo handpiece needed shorter time than the MD handpiece, although it needed longer time than the conventional diamond bur. The use of different handpieces of Er,Cr:YSGG laser did not differ from conventional preparation with diamond bur in terms of microleakage with the tested methacrylate- and silorane-based posterior composite restorative systems.

Microleakage of Sealants after Phosphoric Acid, Er: YAG Laser and Air Abrasion Enamel Conditioning: Systematic Review and Meta-Analysis.

PURPOSE: The aim of this systematic review and meta-analysis is to answer the focused question: Does the application of phosphoric acid, Er:YAG laser and air abrasion enamel conditioning methods previous to the oclusal sealant application in human permanent molars influence the microleakage? STUDY DESIGN: A literature research was carried out in the Pubmed Medline, Web of Science, Scopus and Cochrane databases using with the MeSH terms and keyword search strategy. A supplemental hand search of the references of retrieved articles was also performed. Inclusion criteria comprised ex vivo studies (extracted teeth) with permanent human teeth that used chemical (phosphoric acid) or mechanical (Er:YAG laser and air abrasion) conditioning methods previous the sealant application. The studies should evaluate microleakage as an outcome. Meta-analysis pooled plot were obtained comparing the microleakage after pre-treatment with phosphoric acid, Er:YAG and air abrasion enamel conditioning for sealant application using RevMan software. RESULTS: The search resulted in 164 articles, 55 records were excluded because they were duplicated. The analysis of titles and abstracts resulted in the exclusion of 105 studies. Four studies were included in the systematic review and the meta-analysis. According to the risk of bias evaluation, the four studies were considered low risk of bias. The meta-analysis showed that phosphoric acid had lower microleakage than Er:YAG laser (p < 0.001) and air abrasion (p < 0.001), with heterogeinity of I2 = 0% and I2 = 71%, respectively. It was not found statistical difference when compared phosphoric acid and phosphoric acid combined with Er:YAG laser and air abrasion (p > 0.05). CONCLUSION: The evidence supports that the pretreatment with phosphoric acid leads lower microleakage in oclusal sealants than Er:YAG laser and air abrasion.

Aluminum Oxide Sandblasting of Hexagonal Coping and Abutment: Influence on Retention and Marginal Leakage Using Temporary Cements.

PURPOSE: To compare the tensile strength and marginal leakage of prefabricated abutments/copings, with or without surface sandblasting with aluminum oxide, luted with a calcium hydroxide-based temporary cement (CH, Dycal; Dentsply, Petrópolis, RJ, Brazil) or a noneugenol zinc oxide cement (ZO, Temp Bond NE; Kerr, Orange, CA). MATERIALS AND METHODS: A total of 48 CeraOne abutment analogs and respective copings were divided into 6 groups (n = 8) according to the component that was sandblasted: the coping only, coping + abutment or no sandblasting and the temporary cement used: CH or ZO. After cementation, the samples underwent 500 thermal cycles (5°C ± 2°C and 55°C ± 2°C) and were subsequently immersed in an aqueous solution of 0.5% basic fuchsine dye for 24 hours. Next, the tensile test was performed, and microleakage was assessed qualitatively. Data were analyzed using Mann-Whitney, Kruskal-Wallis tests, followed by the Student-Newman-Keuls test (α = 0.05). RESULTS: CH cement showed a tensile strength (245.6 N) significantly higher than that of the ZO (18.1 N). Sandblasting both abutment and coping increased tensile strength by 1.7 times. Marginal leakage was not influenced by sandblasting; however, CH presented less microleakage. CONCLUSION: Aluminum oxide sandblasting of the coping and abutment favored the tensile strength of temporary cements and the CH showed a higher tensile strength and less microleakage than did the ZO cement.

Effect of proanthocyanidin treatment on the bonding effectiveness of adhesive restorations in pulp chamber.

OBJECTIVE: To analyze the effect of proanthocyanidin (PA) treatment of the pulp chamber dentin after NaOCl and EDTA irrigation on the microleakage and interfacial morphology of adhesive restorations. STUDY DESIGN: Pulp chambers of 66 extracted permanent molars were exposed. In half of the samples, pulp chamber dentin was bonded with Clearfil S3 after irrigation with normal saline (Group1a); 1% NaOCl and 17% EDTA (Group1b) or 1% NaOCl, 17% EDTA and 30% PA (Group1c) and in other half samples, pulp chamber dentin was bonded with Futurabond NR after irrigation with normal saline (Group 2a); 1% NaOCl and 17% EDTA (Group 2b) or 1% NaOCl, 17% EDTA and 30% PA (Group 2c). After adhesive procedures, Filtek Z 250 restorations were placed in the pulp chambers. Microleakage assessment was done in ten samples from each group and scanning electron microscopic examination was done in one sample from each group. Statistical analysis was done using Mann-Whitney and Kruskal Wallis tests at a significance level of P<0.05. RESULTS: Both the adhesives showed extensive microleakage. NaOCl and EDTA irrigation had no significant effect on the microleakage of both the adhesives. PA treatment of the pulp chamber dentin after NaOCl and EDTA irrigation significantly reduced microleakage in both the adhesives. CONCLUSION: It was concluded that 1 minute application of 30% proanthocyanidin solution in the pulp chamber after NaOCl and EDTA irrigation improved the subsequent bonding of self-etch adhesives to pulp chamber dentin.

The efficacy of a cervical barrier in preventing microleakage of Enterococcus faecalis in endodontically treated teeth.

The clinical failure of coronal restorations can compromise the healthy periapical status of endodontically treated teeth. The purpose of the present ex vivo study was to assess the effectiveness of the cervical barrier in preventing bacterial microleakage in the eventual loss of the coronal restoration. Following removal of the smear layer and obturation to the cementoenamel junction using gutta-percha, 70 single-rooted mandibular premolars were randomly divided into five different groups: Group 1 received no additional treatment; Groups 2 and 3 had 2 mm and 3 mm of the obturation removed, respectively, followed by placement of a cervical barrier that was the same thickness as the obturation. In Group 4 (positive control), the root canals were filled only with gutta-percha, while in Group 5 (negative control), the root canals were completely impermeabilized following obturation. The filled root canals were incorporated into a split-chamber model system using Enterococcus faecalis as a microbial marker. The apices were suspended in the lower chambers. Leakage was determined daily for 60 days and evaluated for turbidity. According to Fisher's exact test, the cervical barrier in Groups 2 and 3 prevented the microleakage of E. faecalis into the root canals when compared with Groups 1 and 4. This result was similar to that for the completely sealed samples in Group 5 (p = 0.001).

The effect of different preparation and etching procedures on the microleakage of direct composite veneer restorations.

OBJECTIVES: The aim of this in vitro study was to compare the microleakage of direct composite veneer restorations prepared by a conventional dental bur or Er,Cr:YSGG (erbium, chromium doped yttrium scandium gallium garnet) laser and etched with different procedures. METHODS: Fifty maxillary incisor teeth prepared for direct veneers with gingival margins in dentin and incisal margins in enamel were randomly divided into five groups (n = 10): group 1 (control), prepared with diamond bur and etched with phosphoric acid; group 2, prepared with diamond bur and etched with Er,Cr:YSGG laser (Waterlase MD/Biolase); group 3, prepared with laser and not etched; group 4, prepared with laser and etched with phosphoric acid; and group 5, prepared and etched with laser. After the application of the etch and rinse adhesive system (Prime & Bond NT/Dentsply), teeth were restored with the nano ceramic restorative material (Ceram X Duo/Dentsply), subjected to thermocycling and immersed in 0.5% basic fuchsin dye for 24 h. The teeth were sectioned longitudinally and dye penetration was evaluated by a binocular stereomicroscope equipped with a measuring device. Data were analyzed by Kruskal-Wallis and Wilcoxon signed ranks tests. The level of significance was set at p = 0.05. RESULTS: Significant differences were observed in enamel of the five groups (p < 0.05). Minimal microleakage was observed in groups 1 and 3. The highest microleakage was evaluated in group 5 (p < 0.05). No significant differences were found among the five groups in dentin (p > 0.05). No differences were recorded between the microleakage values in enamel and dentin within each group and this was valid for all groups (p > 0.05). CONCLUSIONS: The results confirmed that enamel and dentin surfaces prepared with Er,Cr:YSGG laser for direct composite veneer restorations may provide comparable sealing.

Novel methodology to evaluate the effect of residual moisture on epoxy resin sealer/dentine interface: a pilot study.

AIM: To evaluate the sealer/dentine interface associated with an epoxy resin sealer using the combination of Goldner's trichrome stain (GTS) and scanning electron microscopy (SEM) to verify the use of the experimental methodology. METHODOLOGY: Extracted human maxillary incisors (6) were subjected to root canal treatment. Subsequent to pulp removal, canal instrumentation and smear layer removal using EDTA and NaOCl, teeth were randomly and equally assigned to a 'wet' or 'dry' group. The 'dry' group was desiccated (95% ethanol/suction/paper points/air-drying), whilst the 'wet' group was treated with a saline rinse/suction/single paper point. Canals were then filled with an epoxy-based resin sealer and warm vertical gutta-percha compaction. After 7-day storage at 37°C, roots from each group were sectioned into apical, middle and coronal horizontal subsections that were cut and split into paired halves and evaluated with GTS or SEM. With GTS sections, hybrid layer and sealer tubular penetration were measured (n=15 measurements/intracanal location/condition) and evaluated using a two-factor repeated measures analysis of variance. The SEM qualitative analysis of paired sections was included as a complementary confirmation of GTS analyses. RESULTS: In dry and wet groups, there was no conspicuous sealer/dentine interface hybrid layer, irrespective of canal location. However, dry specimens exhibited more uniform sealer distribution with deeper tubular penetration in the coronal and middle third (P<0.05). In contrast, there was decreased sealer distribution and tubule penetration in the apical third, regardless of moisture condition (P<0.05). CONCLUSIONS: The experimental methodology (combination of GTS and SEM) can be used to evaluate the intracanal resin sealer/dentine interface. The pilot data indicated that thorough drying of the root canal system may result in improved epoxy resin sealer distribution and deeper resin sealer tubular penetration, especially in the coronal and middle thirds of root canals.

Dimensional alterations and solubility of new endodontic sealers.

This study evaluated the dimensional alterations and the solubility of two experimental endodontic sealers based on Copaifera multijuga oil-resin (Biosealer) and castor oil bean cement (Poliquil), maintained in different storage solutions. Twenty specimens (3 mm diameter and 2 mm height) of each sealer were assigned to 2 groups (n=10) according to the storage solution: simulated tissue fluid (STF) or distilled water (DW). The specimens were stored in these solutions during 90 days, being removed every 30 days for weighting. The solutions were renewed every 15 days. The results were subjected to statistical analysis by Dunn's and Mann-Whitney tests (a=0.05). The solubility of Poliquil was higher in STF (38.4 ± 36.0) than in DW (28.4 ± 15.0), while Biosealer showed higher solubility in DW (34.61 ± 6.0) than in STF (18.59 ± 8.0). The storage solution influenced the behavior of sealers in relation to the weight variation (p=0.0001). Poliquil presented higher variation of weight independent of the solution (p=0.239). Biosealer also presented higher variation of weight regardless of the solution (p=0.0001). The solubility of Biosealer was different from that of Poliquil, but both sealers showed low solubility in STF. Under the tested conditions, neither of the materials were according to the ADA'S specification.

Investigation of coronal leakage of root fillings after smear-layer removal with EDTA or Nd:YAG lasing through capillary-flow porometry.

OBJECTIVE: This study investigates the effects of Nd:YAG laser irradiation combined with different irrigation protocols on the marginal seal of root fillings. BACKGROUND DATA: Limited information exists regarding the effects of morphologic changes to root canal (RC) walls after Nd:YAG laser irradiation after smear-layer removal with EDTA on the sealing ability of root fillings. METHODS: The 75 root-filled teeth (5 × 15 teeth) were analyzed for through-and-through leakage by using capillary flow porometry (CFP). The RC cleaning procedure determined the assignment to a group: (1) irrigation with NaOCl 2.5% and EDTA 17% or standard protocol (SP), (2) SP + Nd:YAG lasing (dried RC), (3) NaOCl 2.5% + Nd:YAG lasing (dried RC), (4) SP + Nd:YAG lasing (wet RC), or (5) NaOCl 2.5% + Nd:YAG lasing (wet RC). Groups 1r to 5r consisted of the same filled teeth with resected apices up to the most apical point of the preparation length. Resection was performed after the first CFP measurement. Roots were filled with cold lateral condensation. CFP was used to assess minimum, mean flow and maximum pore diameters after 48 h, and immediately after these measurements, including root resection. Statistics were performed by using nonparametric tests (p > 0.05). An additional three roots per group were submitted to SEM of the RC wall. RESULTS: Through-and-through leakage was observed in all groups. Statistically significant differences were observed in maximum pore diameter: 1r > 3r, and 1r > 5r; in mean flow pore diameter: 1r > 2r, 2r < 4r (p < 0.05). Typical Nd:YAG glazing effects were observed when the smear layer was present and exposed to the laser fiber (i.e., in the groups without use of EDTA) or when the fiber tip made direct contact with a smear-layer free RC wall. CONCLUSIONS: The reduction in through-and-through leakage is significantly higher with the Nd:YAG laser as smear-layer modifier than when smear layer is removed with an EDTA rinsing solution.

The effect of erbium, chromium:yttrium-scandium-gallium-garnet laser etching on marginal integrity of a resin-based fissure sealant in primary teeth.

The aim of this in vitro study was to evaluate the effect of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser pretreatment alone, or associated with acid etching, on the quality of marginal integrity (microleakage and marginal gap) of a resin-based fissure sealant in primary teeth. Fifty sound primary molar teeth were randomly assigned to one of five study groups, pretreated as follows: (1) 35% orthophosphoric acid etching; (2) 2.5 W laser etching; (3) 3.5 W laser etching; (4) 2.5 W laser + 35% orthophosphoric acid etching; (5) 3.5 W laser + 35% orthophosphoric acid etching. After surface pretreatment, a resin-based sealant (ClinPro) was applied to the fissures. Sample teeth were then subjected to thermocycling and stored thereafter in distilled water at 37 degrees C for 1 month. Following immersion in 0.5% basic fuchsin solution for 24 h, three bucco-lingual slices of each sample tooth were scored under a stereo-microscope. Statistical analysis was performed with Kruskal-Wallis one-way analysis of variance (ANOVA) and Pearson chi-square tests. The level of significance was set at P < 0.05. Microleakage scores of group 1 were significantly less than those of groups 2 and 3 (P < 0.05), whereas no statistically significant difference was observed between groups 1, 4 and 5 (P > 0.05). In terms of marginal gap formation, no significant difference was observed between groups (P > 0.05). It was concluded that Er,Cr:YSGG laser etching did not eliminate the need for acid etching. When combined with acid etching, Er,Cr:YSGG laser seems to be as effective as conventional acid etching.

A three-dimensional evaluation of microleakage of class V cavities prepared by the very short pulse mode of the erbium:yttrium-aluminium-garnet laser.

The aim of this study was to evaluate microleakage along resin restoration in cavities prepared with an erbium:yttrium-aluminium-garnet (Er:YAG) laser, with and without acid etching, and to compare it with that in diamond-drilled cavities. Thirty intact molars were divided into three equal groups. In the teeth in group I, class V cavities were prepared with a diamond drill. Cavities in groups II and III were prepared with an Er:YAG laser (400 mJ/15 Hz for enamel and 250 mJ/10 Hz for dentine). The cavities in groups I and II were acid-etched and adhesive and flowable composite were applied to all cavities. The specimens were first immersed in dye for 24 h and then in 5% nitric acid for 72 h for softening. The fillings were extracted and photographed through a dissecting microscope. The leakage area was measured with specially designed software. The Kruskal-Wallis test showed that the best ranking was group II [mean range (m.r.) = 27.46], followed by group I (m.r. = 33.48) and, lastly, group III (m.r. = 45.15). The differences between groups I and III (P = 0.023) and between groups II and III were statistically significant (P = 0.080). The least microleakage was found in those cavities prepared by Er:YAG laser and subsequently acid-etched, whereas the most leakage was in the lased cavities that had not been etched; the traditional diamond-drilled acid-etched cavities produced medium leakage.

The influence of erbium:yttrium-aluminum-garnet laser ablation with variable pulse width on morphology and microleakage of composite restorations.

The objective of this study was to evaluate the influence of various pulse widths with different energy parameters of erbium:yttrium-aluminum-garnet (Er:YAG) laser (2.94 mum) on the morphology and microleakage of cavities restored with composite resin. Identically sized class V cavities were prepared on the buccal surfaces of 54 bovine teeth by high-speed drill (n = 6, control, group 1) and prepared by Er:YAG laser (Fidelis 320A, Fotona, Slovenia) with irradiation parameters of 350 mJ/ 4 Hz or 400 mJ/2 Hz and pulse width: group 2, very short pulse (VSP); group 3, short pulse (SP); group 4, long pulse (LP); group 5, very long pulse (VLP). All cavities were filled with composite resin (Z-250-3 M), stored at 37 degrees C in distilled water, polished after 24 h, and thermally stressed (700 cycles/5-55 degrees C). The teeth were impermeabilized, immersed in 50% silver nitrate solution for 8 h, sectioned longitudinally, and exposed to Photoflood light for 10 min to reveal the stain. The leakage was evaluated under stereomicroscope by three different examiners, in a double-blind fashion, and scored (0-3). The results were analyzed by Kruskal-Wallis test (P > 0.05) and showed that there was no significant differences between the groups tested. Under scanning electron microscopy (SEM) the morphology of the cavities prepared by laser showed irregular enamel margins and dentin internal walls, and a more conservative pattern than that of conventional cavities. The different power settings and pulse widths of Er:YAG laser in cavity preparation had no influence on microleakage of composite resin restorations.

Dimensional alterations and solubility of new endodontic sealers

This study evaluated the dimensional alterations and the solubility of two experimental endodontic sealers based on Copaifera multijuga oil-resin (Biosealer) and castor oil bean cement (Poliquil), maintained in different storage solutions. Twenty specimens (3 mm diameter and 2 mm height) of each sealer were assigned to 2 groups (n=10) according to the storage solution: simulated tissue fluid (STF) or distilled water (DW). The specimens were stored in these solutions during 90 days, being removed every 30 days for weighting. The solutions were renewed every 15 days. The results were subjected to statistical analysis by Dunn's and Mann-Whitney tests (a=0.05). The solubility of Poliquil was higher in STF (38.4 ± 36.0) than in DW (28.4 ± 15.0), while Biosealer showed higher solubility in DW (34.61 ± 6.0) than in STF (18.59 ± 8.0). The storage solution influenced the behavior of sealers in relation to the weight variation (p=0.0001). Poliquil presented higher variation of weight independent of the solution (p=0.239). Biosealer also presented higher variation of weight regardless of the solution (p=0.0001). The solubility of Biosealer was different from that of Poliquil, but both sealers showed low solubility in STF. Under the tested conditions, neither of the materials were according to the ADA'S specification.

O presente estudo avaliou a alteração dimensional e solubilidade de 2 cimentos experimentais (à base de resina do óleo de Copaíba - Biosealer e cimento do polímero da mamona - Poliquil), mantidos em diferentes meios de armazenamento. Foram confeccionados 20 espécimes de cada cimento com 3 mm de diâmetro e 2 mm de altura os quais foram divididos em 2 grupos (n=10) de acordo com o meio de armazenamento (fluido tissular simulado ou água destilada). Os espécimes foram atidos nas soluções durante 90 dias, sendo removidos a cada 30 dias para pesagem das amostras, no entanto as soluções foram trocadas a cada 15 dias. Os resultados foram submetidos aos testes de Dunn (5 por cento) e Mann-Whitney. Os meios de armazenamento causaram influência no comportamento dos cimentos em relação ao peso (p=0,0001). Poliquil apresentou alta variação de peso independente da solução (p=0,239). Biosealer também apresentou alta variação de peso independente da solução (p=0,0001). A solubilidade do Biosealer foi diferente do Poliquil, entretanto, ambos cimentos mostraram baixa solubilidade no fluido tissular simulado. Nas condições do experimento, nenhum cimento está de acordo com a especificação da ADA.

Evidenced-based review of clinical studies on non-surgical endodontic treatment.

Non-surgical endodontic treatment represents a cornerstone of contemporary endodontic care. Reflecting the central importance of this therapy, there is a high number of studies that address issues related to this treatment. Unfortunately, many of these studies are preclinical "bench top" studies with largely undefined clinical implications. Given its high level of importance, we encourage others to conduct high-quality endodontic studies in this area. The following represents an analysis of recent clinical studies on nonsurgical endodontic treatment.

Sealing ability of castor oil polymer as a root-end filling material

OBJECTIVE: The purpose of this study was to evaluate the sealing ability of castor oil polymer (COP), mineral trioxide aggregate (MTA) and glass ionomer cement (GIC) as root-end filling materials. Forty-five single-rooted human teeth were cleaned and prepared using a step-back technique. The apical third of each root was resected perpendicularly to the long axis direction. All teeth were obturated with gutta-percha and an endodontic sealer. After, a root-end cavity with 1.25-mm depth was prepared using a diamond bur. The specimens were randomly divided into three experimental groups (n=15), according to the root-end filling material used: G1) COP; G2) MTA; G3) GIC. The external surfaces of the specimens were covered with epoxy adhesive, except the root-end filling. The teeth were immersed in rhodamine B dye for 24 hours. Then, the roots were sectioned longitudinally and the linear dye penetration at the dentin/material interface was determined using a stereomicroscope. ANOVA and Tukey's tests were used to compare the three groups. The G1 group (COP) presented smaller dye penetration, statistically different than the G2 (MTA) and G3 (GIC) groups (p<0.05). No statistically significant difference in microleakage was observed between G2 and G3 groups (p>0.05). The results of this study indicate that the COP presented efficient sealing ability when used as a root-end filling material showing results significantly better than MTA and GIC.

Sealing ability of castor oil polymer as a root-end filling material.

OBJECTIVE: The purpose of this study was to evaluate the sealing ability of castor oil polymer (COP), mineral trioxide aggregate (MTA) and glass ionomer cement (GIC) as root-end filling materials. Forty-five single-rooted human teeth were cleaned and prepared using a step-back technique. The apical third of each root was resected perpendicularly to the long axis direction. All teeth were obturated with gutta-percha and an endodontic sealer. After, a root-end cavity with 1.25-mm depth was prepared using a diamond bur. The specimens were randomly divided into three experimental groups (n=15), according to the root-end filling material used: G1) COP; G2) MTA; G3) GIC. The external surfaces of the specimens were covered with epoxy adhesive, except the root-end filling. The teeth were immersed in rhodamine B dye for 24 hours. Then, the roots were sectioned longitudinally and the linear dye penetration at the dentin/material interface was determined using a stereomicroscope. ANOVA and Tukey's tests were used to compare the three groups. The G1 group (COP) presented smaller dye penetration, statistically different than the G2 (MTA) and G3 (GIC) groups (p<0.05). No statistically significant difference in microleakage was observed between G2 and G3 groups (p>0.05). The results of this study indicate that the COP presented efficient sealing ability when used as a root-end filling material showing results significantly better than MTA and GIC.

In vitro evaluation of the sealing ability of MTA used for the repair of furcation perforations with and without the use of an internal matrix.

OBJECTIVE: To evaluate the effect of matrix on mineral trioxide aggregate (MTA) when used to repair furcal perforations. STUDY DESIGN: Forty-five human molars with furcal perforations were randomly divided into 3 groups and repaired with MTA either alone or over a barrier (calcium sulfate or Collaplug). Eight teeth without perforations provided negative control samples. After assessing repair quality, 1 mol/L glucose solution was used as the tracer to detect the leakage. The concentration of leaked glucose was measured after 1, 2, 4, 7, 15, and 20 days using a glucose oxidase method. RESULTS: No significant difference in either leakage or overfilling was found between the groups with Collaplug and MTA alone (P > .05). Although no overfilling was detected in the group with calcium sulfate, that group had the most leakage (P < .05). CONCLUSIONS: Neither of the 2 internal matrices improved the sealing ability and reduced the incidence of overfilling simultaneously.

Comparison of preparation design and material thickness on microbial leakage through Cavit using a tooth model system.

Few studies have compared Cavit thickness and access design as factors in microbial leakage. The present study used an acrylic tooth model to measure leakage of Streptococcus mutans. Pilot studies confirming the sterility of Cavit showed it will inhibit microbial growth for 2 days. The experiments compared class I preparations where Cavit thickness was 4 mm with class II preparations where thickness was 2-3 mm. Accesses sealed with cotton pellets were compared with those without cotton. Results of the study showed no bacterial contamination in any of the class I samples (up to 14 days). Some class II samples showed contamination at day 1 (3 out of 14), with all contaminated at day 7 (14 of 14), yet only 1 contaminated at day 14 (1 out of 14). The results suggest that a 4-mm thickness of Cavit should prevent bacterial ingress for at least 2 weeks, but microbial leakage may occur if temporary thickness is less than 3 mm or in a complex access preparation.