Longitudinal evaluation of the microleakage of dentin bonding agents used to seal resected root apices

Selective Retreatment and Sinus Lift: An Alternative Approach to Surgically Manage the Palatal Roots of Maxillary Molars

Endodontic microsurgery on the palatal root of maxillary molars presents a clinical challenge because of the root position and approximation from the maxillary sinus floor. Attempting a buccal or a palatal approach to address the root is associated with limited accessibility and visibility as well as the risk of injury to the maxillary sinus membrane and/or the greater palatine nerves and vessels. If all the maxillary molar roots require surgical intervention, two flaps may even be needed, which can make the procedure technically more difficult and lengthier. This case report presents 2 clinical cases in which apicoectomy was needed on the palatal roots of maxillary molars. The treatment includes selective nonsurgical retreatment of the palatal root and obturation using a root repair material followed by a surgical intervention from a buccal approach to treat the buccal roots, sinus lift using piezosurgery, and root resection of the palatal root. The approach was successful in both cases without any untoward events. We monitored the radiographic changes using cone-beam computed tomographic imaging immediately after the surgery and at multiple follow-up appointments. The cone-beam computed tomographic images revealed healing of the periapical disease around all the roots up to 14 and 24 months and apical repositioning of the maxillary sinus floor.

Bacterial leakage in root canals filled with AH Plus and dentine bonding agents

OBJECTIVE

The aim of this study was to compare the efficacy of different dentine adhesives in delaying the coronal bacterial leakage of Enterococcus faecalis in filled root canals. Materials and methods. Ninety-five lower incisors of patients >65 years of age were instrumented using the ProTaper system and were irrigated with 1 mL of 2.5% sodium hypochlorite (NaOCl) alternated with 1 mL 17% EDTA between each file change. Final irrigation was performed with 5 mL of 17% EDTA and then flushed with 5 mL of distilled water. The teeth were randomly divided into five experimental groups (n = 15/group) and one of the following dentine adhesives was applied: (1) AdheSE; (2) Excite DSC; (3) Clearfil Protect Bond; (4) One Coat 7.0; or (5) Control group without adhesive. After filling the root canals, the samples were mounted on a double chamber device to evaluate the bacterial filtration of E. faecalis during a period of 240 days. The results underwent non-parametric Kaplan-Meier survival analysis and comparisons among groups were done using the Log-Rank test.

RESULTS

At 240 days, E. faecalis was detected in samples of all groups in the lower chamber. The highest survival value was obtained by One Coat 7.0, giving statistically significant differences from the other groups, whereas Clearfil Protect Bond, AdheSE and Excite DSC showed similar behaviours, likewise similar to the Control group.

CONCLUSIONS

One Coat 7.0 adhesive system provides the longest survival value to delay E. faecalis coronal leakage in filled root canals.

Influence of blood contamination before or after surface treatment on adhesion of 4-META/MMA-TBB resin to root dentin

The purpose of this study was to evaluate the influence of blood contamination before or after surface treatment on adhesion of 4-META/MMA-TBB resin. After bovine root dentin surfaces were contaminated with blood before or after dentin surface treatment with 10-3 solution, the contaminated surface was rinsed with water, air-dried, or re-treated with 10-3 solution. Dye leakage and microtensile bond strength (MTBS) of 4-META/MMA-TBB resin to dentin were measured after storage in water for 24 h. When blood contamination occurred before surface treatment, there was no significant difference in the leakage value and MTBS as compared with that of the uncontaminated group. When blood contamination occurred after surface treatment, the leakage value increased and MTBS significantly decreased (p<0.05) even if the blood was washed away. However, when the surface was re-treated with 10-3 solution after rinsing with water, the leakage value and MTBS were restored to those of the uncontaminated group.

Microleakage of endodontically treated teeth with different dowel systems

STATEMENT OF PROBLEM

Several new esthetic dowel systems are available for the restoration of endodontically treated teeth, but little is known about how effectively these dowels seal the restored teeth.

PURPOSE

The purpose of this in vitro study was to compare microleakage of 3 esthetic, adhesively luted dowel systems with a conventional dowel system.

MATERIAL AND METHODS

The root canals of 41 human intact single-rooted extracted teeth were prepared using a step-back technique. The teeth were randomly divided into 4 experimental groups (n=10), and 1 tooth served as a positive control. The decoronated roots were obturated with gutta-percha using lateral condensation. Roots were restored with 1 of the following dowel systems according to the manufacturer's instructions: (1) stainless steel dowels (ParaPost), (2) glass fiber dowels (Snowpost), (3) resin-supported polyethylene fiber (Ribbond) dowels, or (4) zirconia dowels (Cosmopost). Using a fluid filtration method, coronal leakage of the specimens along the dowel space and root canal restorative material was measured. Fluid movement measurements were made at 2-minute intervals for 8 minutes to measure the presence of voids existing in the obturated canals, at 1 week, 3 months, and 6 months following dowel insertion. A repeated-measures analysis of variance (ANOVA) was used to analyze logarithmic transformations of data (time and dowel material) for significant differences. The Tukey HSD test and paired 2-tailed tests were used to perform multiple comparisons (alpha=.05).

RESULTS

The data indicated that the leakage values varied according to the dowel system used (P<.01). There was significant interaction between dowel systems and time of testing (P<.01). The sealing ability of zirconia dowels decreased over time (P<.01), but sealing abilities of stainless steel and resin-supported polyethylene fiber dowels remained constant (P>.05). The sealing ability of glass fiber dowels increased at 3 months (P=.032) and remained constant over the next 3 months (P=.758). Statistically, resin-supported polyethylene fiber and glass fiber dowels showed the lowest coronal leakage when compared with stainless steel and zirconia dowels at all time periods (P<.01). There were no significant differences between resin-supported polyethylene fiber and glass fiber dowels at any time period. The initial leakage measurement in zirconia dowel and stainless steel dowels were similar (P=.914), but became significantly different at 3 and 6 months (P<.01).

CONCLUSION

Resin-supported polyethylene fiber dowels and glass fiber dowels tested exhibited less microleakage compared to zirconia dowel systems. The latter system should be further evaluated because of its unacceptable level of leakage.

Use of Self-Etching Adhesives to Seal Resected Apices

The purpose of this study was to evaluate the sealing ability of four self-etching adhesives placed over blood-contaminated/uncontaminated resected root apices without root-end preparation. Extracted maxillary incisors and canines were randomly divided into four groups of 10 teeth each. After canal preparation and resection of the apex, four self-etching adhesives (Clearfil SE Bond, One-Up Bond F, Unifil Bond, and ABF) were applied over the control and contaminated surfaces. The roots were then subjected to 15 cm of water pressure to simulate periapical microleakage stress. Data were analyzed using a two-way repeated measures, ANOVA. Positive and negative controls responded as expected. Statistical analysis indicated that there were no significant differences in the sealing effectiveness among the adhesives applied to contaminated or uncontaminated groups. All contaminated groups had significantly higher leakage (p < 0.003) than their uncontaminated pairs.

The effectiveness of compomer as a root-end filling: a clinical investigation

OBJECTIVE

This study investigates the treatment outcome of a root-end filling technique that uses a light-cured compomer combined with a light-cured dental adhesive.

STUDY DESIGN

The study used 34 single-rooted teeth restored with post, core, and crowns. A shallow concave apical preparation was filled with a light-cured compomer with a light-cured dental adhesive. As a control, a chemically cured glass ionomer was used with a conventional root-end preparation. A follow-up clinical and radiographic evaluation of the treatment result was conducted after 1 year.

RESULTS

A significantly higher success rate (P<.015) was observed in the treatment group that used a compomer (89% complete healing) compared to glass ionomer (44% complete healing).

CONCLUSIONS

When used as a retrograde root filling in a shallow concave preparation, a light-cured compomer and a dental adhesive improves healing regardless of the quality of the remaining root filling.

Blood contamination and dentin bonding--effect of anticoagulant in laboratory studies

OBJECTIVE

To investigate the influence of heparinized blood vs. native blood on the marginal adaptation of dentin bonded composite resin restorations.

METHODS

Cylindrical dentin cavities were prepared in 40 extracted human incisors. After acid-etching four groups (n=10) were contaminated with either fresh capillary blood (FCB), heparinized venous blood (HPB), saline (SAL) or heparinized saline (HPS) and bonded and filled with Scotchbond 1/Z 100. After water storage for 21 days and thermocycling (2000 x, 5-55 degrees C), replicas were produced for evaluation of marginal adaptation by means of quantitative marginal analysis in the SEM. Statistical analysis was performed with the Kruskal-Wallis-test and the Bonferroni correction for multiple comparisons at p<0.05.

RESULTS

There were no differences between groups SAL, HPS and HPB. Contamination with fresh capillary blood resulted in significantly higher amounts of marginal openings compared to all other groups.

SIGNIFICANCE

Freshly drawn blood has to be used for blood contamination experiments in laboratory studies.

In vitro bacterial penetration of endodontically treated teeth coronally sealed with a dentin bonding agent

This study evaluated the effectiveness of a dentin bonding agent as a barrier to prevent coronal microleakage and examined the effect of a eugenol-based sealer on the sealing ability of this resin adhesive. Fifty-one extracted human mandibular molars were incorporated in a model system using an oral streptococci as a microbial marker. Group 1 consisted of 15 teeth that were obturated with only gutta-percha and received a coronal barrier of Clearfil Liner Bond 2V. Group 2 was identical to group 1, but included the use of a eugenol-based sealer in the obturation. Group 3 consisted of 15 teeth that were obturated with gutta-percha and sealer, but did not receive a coronal barrier. Six teeth served as controls. Bacterial penetration was monitored for 90 days. Results were analyzed after 30, 60, and 90 days with Fisher's exact test (p < 0.05). All controls behaved as expected. Neither group 1 nor group 2 exhibited any bacterial leakage. Eleven of the 15 specimens in group 3 leaked between 15 and 76 days. The coronal barriers in group 1 and group 2 were significantly better in preventing coronal microleakage at 60 days (p = 0.002) and 90 days (p = 0.00005). The presence of eugenol in the sealer had no significant effect on the sealing ability of Clearfil Liner Bond 2V (p = 1).

A comparative evaluation of three root-end filling materials: an in vitro leakage study using Prevotella nigrescens

This study used Prevotella nigrescens to evaluate the sealing ability of Geristore, Super-EBA, and ProRoot when used as root-end filling materials. One hundred single-canal, extracted, human teeth were cleaned and shaped with Gates-Glidden burs and .04 Taper (ProFile Series 29) rotary instruments. The root-ends were resected, and a 3-mm deep root-end preparation was made with ultrasonic tips. After steam sterilization, the teeth were randomly divided into three groups of 30. Each group was root-end-filled with a different material. Five root-end cavities were left open and served as positive controls; another five root-end cavities filled with sticky wax and covered with two layers of nail polish acted as negative controls. The teeth were attached to presterilized snap-on plastic caps; the root-ends submerged into 12-ml vials of chopped meat carbohydrate broth and placed in an anaerobic chamber. Twice a week, a sterile micropipette was used to inoculate 0.1 ml of a broth culture of Prevotella nigrescens into the root canal of each tooth. Results after 47 days indicated there were no significant differences between the three root-end filling materials against penetration of Prevotella nigrescens.

Considerations in the selection of a root-end filling material

Surgical root canal treatment often includes the placement of a root-end filling material. New materials have recently emerged to challenge the long-standing position of amalgam as the root-end filling material of choice. This review discusses several of the commonly used root-end filling materials, with emphasis on indications and contraindications for the use of each.

In vitro sealing ability of dentin bonding agents and cavity varnish with amalgam as retrofills

The aim of this study was to test the effect on the seal produced by an amalgam retrofill of two dentin bonding agents (Amalgambond and All-Bond) and a cavity varnish (Copalite). The three materials were tested when placed before the retrofill (group I) and before and after the retrofill (group II). Ninety teeth distributed into three groups were prepared for the retrofilling. Each group was divided into subgroups of I and II. Linear apical leakage was measured by a stereomicroscope after 1 month in dye. All materials permitted dye leakage around the retrofill, regardless of the application type. No statistical difference was found between the Amalgambond subgroups or between the All-Bond subgroups. There was less leakage in varnish group I than group II. Amalgambond group I leaked significantly less than All-Bond group I.

Effect of dentin bonding agents on the secretion of inflammatory mediators from macrophages

Dentin bonding agents (DBAs) have been proposed as substitutes for amalgam as root-end filling materials. The current study tested the hypothesis that certain components of DBAs could alter the secretion of cytokines from macrophages. Such alteration would likely be undesirable for healing of the periapical tissues. Human THP-1 macrophages were exposed to 2-hydroxyethyl methacrylate, 4-methacryloxyethyl trimelliate anhydride, bisphenol-gycidylmethacrylate, and urethane dimethacrylate. The secretion of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) were measured with or without challenge by lipopolysaccharide (LPS). Results showed that all DBA components completely suppressed LPS-induced IL-1 beta and TNF-alpha secretion at concentrations that suppressed mitochondrial activity by 50%. In addition, 4-methacryloxyethyl trimelliate anhydride induced secretion of IL-1 beta, but not TNF-alpha, without the LPS challenge. These results indicate that DBA components may alter normal macrophage-directed inflammatory responses if the macrophages are exposed to sufficiently high concentrations of these components.

Effects of dentin bonding agents on macrophage mitochondrial activity

Dentin bonding agents (DBA) have been considered for use as root-end fillings. Previous studies have documented the release of DBA components in vivo and in vitro, but the biological implications are not clear. The macrophage is important in wound healing, and likely to be important in any inflammatory response. Therefore, this study determined the concentrations of the components of DBAs that suppress the mitochondrial activity of human macrophages in vitro. THP-1 macrophages were cultured in the presence of four DBA components (2-hydroxyethyl methacrylate (HEMA), 4-methacryloxyethyl trimellitate anhydride (4-META), bisphenol-glycidylmethacrylate (Bis-GMA), and urethane dimethacrylate (UDMA)) at various concentrations and for varying durations. Residual effects were also measured after the resins were removed. Controls received only the vehicle solution, ethanol or water. THP-1 mitochondrial activity was estimated using the MTT assay, and the 50% toxicity concentrations (TC50) were determined graphically. Resin components suppressed the mitochondrial activity of macrophages at different concentrations (TC50 values for HEMA (10,000 mumol/L), 4-META (3,800 mumol/L), Bis-GMA (130 mumol/L), and UDMA (110 mumol/L) at 24 h, and the effect was time-dependent. Residual effects were observed for all resins.

A new single-step technique for apical retrofilling that significantly reduces microleakage

One of the properties of an ideal retrofilling material is little or no microleakage. A new dentin bonding agent based on polyacrylic acid (PAA) is ideally suited to the moist apical environment because of its hydrophilic nature. PAA as a dentin bonding agent for apical retrofillings was tested in an in vivo leakage study using single canal roots of extracted human teeth. Bonding was attained by pretreatment of the dentin in apical retrofilling preparations with a solution of PAA, followed by placement of a nonaqueous restorative material. Using PAA as dentin bonding agent reduced apical leakage at statistically significant levels with Super EBA as a restorative material. In vivo testing is required to validate these findings.

Review of dental materials citations: Part B, July to December 1995

OBJECTIVE

A lag of many months occurs between journal issue publication and updates to electronic databases. The objective of this literature analysis was to identify and categorize all of the dental materials citations in biomedical journals that were published from July 1995 through December 1995.

METHODS

Seventeen primary and 51 secondary journals were searched using their tables of contents to detect and record dental materials publications from July to December of 1995. Those journals that were typically rich in dental materials articles were classified as primary ones. Citations were categorized into 17 topics and divided into subsections. The review excluded case reports, most literature related primarily to dental implants, and most articles on biomedical materials used outside of the field of general dentistry.

RESULTS

The greatest number of citations was related to topics of dentin bonding and resin-based restorative filling materials (composites and glass ionomers). There was no major change in the number of dental materials publications per year reported from 1993 (n = 786) to 1995 (n = 751).

SIGNIFICANCE

This citation list provides a comprehensive resource for use by academicians and researchers to bridge the gap between initial publication and access to electronic searching methods for major databases.