Effect of ferric sulfate contamination on the bonding effectiveness of etch-and-rinse and self-etch adhesives to superficial dentin

Aim:

This study investigated the effect of one hemostatic agent on the shear bond strength of self-etch and etch-and-rinse adhesive systems.

Materials and Methods:

Sixty extracted third molars were selected. After preparing a flat surface of superficial dentin, they were randomly divided into six groups. Adhesives were Tetric N-Bond, AdheSE, and AdheSE One F. Before applying adhesives, surfaces were contaminated with ViscoStat for 60 s in three groups and rinsed. Then composite were attached to surfaces and light cured. After thermocycling, the bond strength was calculated and failure modes were determined by stereomicroscope. The data were analyzed by t-test and one-way ANOVA with P < 0.05 as the level of significance.

Results:

ViscoStat had significantly decreased the shear bond strength of AdheSE (P < 0.0001) to dentin. Modes of failures in all groups were mainly adhesive.

Conclusion:

Contamination had an adverse effect on the shear bond strength of AdheSE and reduced it.

The minimum thickness of a multilayer porcelain restoration required for masking severe tooth discoloration

Background:

Materials and Methods:

Results:

Conclusion:

Effect of chlorhexidine on the durability of a new universal adhesive system

Background

The effect of chlorhexidine on bond durability of universal adhesives is not clear. The aim of this study was to evaluate the effect of chlorhexidine on 6-month water storage bond strength of adhesive systems.

Material and Methods

72 freshly sound human extracted molars were selected. In each tooth both buccal and lingual sides were prepared by bur to reach superficial dentin and randomly divided into 6 groups and 12 sub-groups and bonded with Scotchbond Universal (SBU) or Scotchbond Multi-purpose (SBMP) with/without chlorhexidine (CHX) usage. Group 1: SBU, group2: SBU+CHX, group3: Etch+SBU, group4: Etch+CHX+SBU, group5: Etch+SBMP, group6: Etch+CHX+SBMP. After composite curing, water storage and thermocycling was done. Each group was divided into two subgroups. One was tested immediately, and the other was thermocycled for 5000 cycles (5-55 °C) (it was equivalent to 6 months of storage in distilled water). Shear bond strength test was done and failure modes were determined by Stereomicroscope. The data were analyzed by one-way ANOVA, Tukey post-hoc test and Paired Two test with P<0.050 as the level of significance.

Results

Shear bond strength in late SBU (Self etch) was significantly lower than late SBU [Etch and rinse (ER)], P value= 0.0001, also shear bond strength in late SBU [self-etch (SE)] was significantly lower than immediate SBU (SE), P value= 0.01. There were no significant differences between other sub-groups and conditions. The most failure mode was adhesive in all the groups.

Conclusions

Long term bonding durability of SBU(ER) was better than SBU (SE). CHX usage had prevented bond strength decrease in SBU and SBMP in long term. CHX usage did not have any effect on immediate shear bond strength of SBU and SBMP. Immediate and late shear bond strength of SBMP with/without CHX usage was similar to SBU(SE, ER). Key words:Dentin Bonding, Shear Bond Strength, chlorhexidine, 6-month storage.

Effectiveness of Amlexanox and Adcortyl for the treatment of recurrent aphthous ulcers

Background

Recurrent aphthous stomatitis (RAS) is a common condition that affects approximately 20% of the general population. The ulcers can interfere with speech and eating and cause significant pain and discomfort. This study aimed to evaluate the efficacy of Amlexanox and Adcortyl in the treatment of aphthous ulcers.

Material and Methods

In this randomized double blind clinical trial with sequential patient entry, a total of 40 patients who presented with aphthous ulcers were included. Patients were received Amlexanox or Adcortyl four times daily for 7 days. Patients were evaluated for pain, lesion size, and tingling at one day, three days, five days and seven days follow-ups. The treatment effects were then evaluated using the Wilcoxon–Mann–Whitney (WMW) test. Values of p<0.05 were considered significant.

Results

No significant differences in pain score, tingling and lesion size were observed on similar days between Amlexanox and Adcortyl groups. In both groups, reduction in the assessed variables was significant between days 1-3, 3-5, and 5-7 (p < 0.001).

Conclusions

This study indicated that Amlexanox as well as Adcortyl was effective in relieving pain and reducing the lesion size during the treatment of aphthous ulcers.

Key words:Recurrent aphthous stomatitis, Amlexanox, Adcortyl, pain relief.

Casein phosphopeptide-amorphous calcium phosphate and shear bond strength of adhesives to primary teeth enamel

Background:

CPP-ACP (Phosphopeptide-Amorphous Calcium Phosphate) has an important role in caries prevention in pediatric patients. This study was done, because of the great use of CPP-ACP and the need for restoration for teeth treated with CPP-ACP as well as the importance of shear bond strength of adhesives in the success of restorations.

Objectives:

This study aimed to evaluate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on shear bond strength of dental adhesives to enamel of primary teeth molars.

Materials and Methods:

This in vitro study was conducted on 180 extracted primary molars. They were randomly divided into 6 groups and each group was divided into 2 subgroups (treated with CPP-ACP and untreated). In subgroups with CPP-ACP, enamel was treated with CPP-ACP paste 1 h/d for 5 days. Types of adhesives that were evaluated in this study were Tetric N-Bond, AdheSE, AdheSE One F, single Bond 2, SE Bond, and Adper Prompt L-Pop. Shear bond strength was tested with a universal testing machine and mode of failure was evaluated under stereomicroscope. Data were analyzed by T test, 2-way analysis of variance (ANOVA), Tukey and Fisher exact test using SPSS18. P < 0.05 was considered as significance level.

Results:

Shear bond strengths of different adhesive systems to enamel of primary teeth treated and untreated with CPP-ACP showed no significant difference (P > 0.05). Mode of failure in all groups regardless of CPP-ACP administration was mainly adhesive type. Our results indicated that CPP-ACP did not affect shear bond strength of studied adhesives to primary teeth enamel.

Conclusions:

To have a successful and durable composite restoration, having a high strength bonding is essential. Considering the wide use of CPP-ACP in preventing tooth decay and the role of adhesive shear bond strength (SBS) in success of composite restoration, we conducted the present study to evaluate the effect of CPP-ACP on the SBS of adhesives to primary teeth enamel.

Shear Bond Strength of a Multi-Mode Adhesive to Bur-Cut and Er,Cr:YSGG Lased Dentin in Different Output Powers

STATEMENT OF THE PROBLEM

Universal or multi-mode adhesives are new adhesive systems that can be used in both etch-and-rinse (ER) and self-etch (SE) modes. Lesser technical sensitivity and dual use of these adhesives have made them popular among dentists. Studies are being conducted to analyze the advantages and disadvantages these adhesives in different conditions.

PURPOSE

The aim of this study was to compare shear bond strength (SBS) of a multi-mode adhesive in different etching modes to Er,Cr:YSGG laser ablated and bur-cut dentin.

MATERIALS AND METHOD

Buccal and lingual surfaces of 30 sound human molars, randomly divided to three groups, were prepared by bur and Er,Cr:YSGG (4 Watt and 5 Watt, 20 Hz, 96% water, 60% air, and 600-µm spot size) to reach a flat surface in superficial dentin. Each group was randomly divided into 2 subgroups (ER and SE), and then Scotchbond Universal adhesive was applied. Composite cylinders were attached to the surfaces and cured. Specimens were stored in 37 °C water for 24 hours and thermocycled (500 cycles) and were tested for SBS and failure modes were determined by stereomicroscope. Data was analyzed using SPSS19 and one- way ANOVA and Tukey's post hoc tests and p< 0.05 was considered as significance level.

RESULTS

Bur-cut dentin with ER method had the highest mean SBS value (33.80 MPa). SBS in bur-cut and 4Watt laser in ER mode were significantly higher than SE mode (p= 0.002 and p= 0.000 respectively). Highest mean SBS value in lased dentin was achieve in 4 Watt ER mode.

CONCLUSION

SBS of Scotchbond universal adhesive to dentine is highest in bur-cut and ER mode and in 4-Watt lased-dentin is higher than 5-Watt lased-dentin. Moreover, in 4-Watt lased-dentin, SBS of ER mode is more than SE mode.

Antibacterial, physical and mechanical properties of bonding agent containing synthesized Zinc Dimethacrylate

Background

The aim of this study includes synthesis of zinc dimethacrylate ionomer (ZDMA) by a new method, incorporate it into resin bonding and evaluate its antibacterial, physical and mechanical properties.

Material and Methods

Resin adhesives containing 0 to 5% wt of ZDMA was produced and the following tests were accomplished: A: Antibacterial test: 1.Direct contact test. 2.Material aging; in both of them the bacterial colony counting were performed. B: Physical test: 1.Degree of conversion (D.C). 2.Evaluating the amount of released Zinc ion release in aqueous medium. C: Mechanical test: 1.Compressive strength test. 2.Shear bond test (enamel and dentine separately). The obtained results were statistically analyzed using One Way ANOVA and LSD post hoc test (α=0.05).

Results

The anti-bacterial test revealed that all the ZDMA containing groups significantly reduced the amount of Streptococcus Mutans bacteria. Moreover, the D.C in all ZDMA groups was enhanced. Furthermore, ion release analysis revealed noticeable stability of Zn2+ in samples, as in the 5wt.% group it was even after nine cycle of 24h wash. On the other hand, the compressive strength was significantly reduced just in the 5% ZDMA group while the other groups were superior comparing to the control. In addition, there was no significant difference among the enamel shear bond strength of the groups. However, about the dentine shear bond strength, only the 5% ZDMA group was significantly higher than the control.

Conclusions

Low percentages of ZDMA in adhesive could impart anti-bacterial efficacy without challenging its mechanical and physical properties.

Key words:Dental Resin Bonding, Zinc, Streptococcus mutans, Degree of conversion, Compressive strength.

Sealing of adhesive systems in ferric sulfate-contaminated dentinal margins in class V composite resin restorations

Background. Hemostatic agents are applied to prepare an isolated bleeding-free condition during dental treatments and can influence adhesive restorations. This study evaluated the effect of a hemostatic agent (ViscoStat) on microleakage of contaminated dentinal margin of class V composite resin restorations with three adhesives. Methods. Sixty freshly extracted human molars were selected and class V cavities (3×3×1.5 mm) were prepared on buccal and lingual surfaces. Gingival margins of the cavities were placed below the cementoenamel junction. The teeth were divided into six groups randomly. The adhesives were Excite, AdheSE and AdheSE One. In three groups, the gingival walls of the cavities were contaminated with ViscoStat and then rinsed. The cavities were restored with composite resin and light-cured. After storage in distilled water (37°C) for 24 hours and polishing, the samples were thermocycled and sealed with nail varnish. Then they were stored in 1% basic fuchsin for 24 hours, rinsed and mounted in self-cured acryl resin, followed by sectioning buccolingually. Dye penetration was observed under a stereomicroscope and scored. Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U tests. P<0.05 was set as the level of significance. Results. Only in the Excite group, contamination did not have adverse effects on dentin microleakage (P > 0.05). In the contaminated groups, Excite had significantly less microleakage than the others (P = 0.003). AdheSE and AdheSE One did not exhibit significant difference in microleakage (P > 0.05). Conclusion. ViscoStat hemostatic agent increased dentinal microleakage in AdheSE and AdheSE One adhesives with no effect on Excite.

In vitro evaluation of casein phosphopeptide-amorphous calcium phosphate effect on the shear bond strength of dental adhesives to enamel

BACKGROUND

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is applied for remineralization of early caries lesions or tooth sensitivity conditions and may affect subsequent resin bonding. This in vitro study investigated the effect of CPP-ACP on the shear bond strength of dental adhesives to enamel.

MATERIALS AND METHODS

Sixty extracted human molar teeth were selected and randomly divided into three groups and six subgroups. Buccal or lingual surfaces of teeth were prepared to create a flat enamel surface. Adhesives used were Tetric N-Bond, AdheSE and AdheSE One F. In three subgroups, before applying adhesives, enamel surfaces were treated with Tooth Mousse CPP-ACP for one hour, rinsed and stored in 37°C temperature with 100% humidity. This procedure was repeated for 5 days and then adhesives were applied and Tetric N-Ceram composite was adhered to the enamel. This procedure was also fulfilled for the other three subgroups without CPP-ACP treatment. After 24 hour water storage, samples were tested for shear bond strength test in a universal testing machine. Failure modes were determined by stereomicroscope. Data were analyzed by t-test and one-way analysis of variance with P < 0.05 as the level of significance.

RESULTS

In comparison between applied and non-applied CPP-ACP subgroups, there was no significant decrease in the shear bond strength to enamel only in Tetric N-Bond (P > 0.05). In non-applied CPP-ACP subgroups, there were statistically significant differences among all subgroups. Tetric N-Bond had the highest and AdheSE One F had the lowest shear bond strength.

CONCLUSION

CPP-ACP application reduces the shear bond strength of AdheSE and AdheSE One F to enamel but not Tetric N-Bond.

Peripheral giant cell granuloma: a review of 123 cases

BACKGROUND

Peripheral giant cell granuloma is one of the reactive hyperplastic lesions of the oral cavity, which originates from the periosteum or periodontal membrane following local irritation or chronic trauma. The purpose of this study was to present the clinical characteristics of peripheral giant cell granuloma in a group of Iranian population.

METHODS

A series of 123 consecutive confirmed cases of peripheral giant cell granuloma after biopsy were evaluated. Age, sex, anatomic location, consistency, etiologic factor, pain and bleeding history, color, surface texture, and pedicle situation were recorded and were analyzed by chi-square test and values were considered to be significant if P < 0.05.

RESULTS

Age ranged from 6 to 75 years (mean 33 years). Women affected more than men (M/F 1:1.1). Peripheral giant cell granuloma was seen in the mandible more than in the maxilla and in the anterior region more than in the posterior region. In most cases, lesions were pink, pedunculated and had non-ulcerated surface. In less than half of the cases, there was no history of bleeding and also pain was rarely reported. Calculus was the most common etiologic factor.

CONCLUSION

The results confirmed that the clinical features of peripheral giant cell granuloma in a group of Iranian population are almost similar to those reported by other investigators.

The minimum thickness of a multilayer ceramic restoration required for masking dark background

Background

Masking dark tooth structure or darkness of oral cavity with ceramic restorations is an important concern. The aim of this study was to determine the minimum thickness of a multilayer all-ceramic restoration (IPS-emax Press) required for a proper masking in these situations.

Materials and Methods

In this experimental in vitro study, 36 multilayer ceramic disks of IPS e.max Press (IvoclarVivadent, Schaan, Liechtenstein) with the diameter of 13 mm were prepared and allocated in six groups of different core/veneer thicknesses: 0.4/0.4 mm (G1), 0.5/0.5 mm (G2), 0.6/0.6 mm (G3), 0.8/0.7 mm (G4), 1.0/0.8 mm (G5), and 1.1/0.9 mm (G6). For backgrounds, the standard black tile of spectrophotometer (B) was used to stimulate the darkness of oral cavity, and an opaque ceramic (OC) of IPS-emax Press (OC) was fabricated to determine the masking ability. CIELAB values of all disks on B and OC backgrounds were measured, and ΔE was calculated between two backings. One-way ANOVA and post hoc tukey test were used to analyze the data. ΔE ≤3.3 and P < 0.05 were considered, respectively, as the clinically acceptable limit and the level of statistical significancy.

Results

The mean ΔE between B and OC of groups 4 (2.83 ± 0.80) and 5 (1.46 ± 0.36) were within the range of the clinically acceptable color difference (ΔE ≤3.3); thus these groups could properly mask the black background. A trend was existed in the results as by increasing the thickness, ΔE was decreased.

Conclusion

A thickness of 1.5 mm of a multilayer ceramic restoration (IPS e.max Press) is required to mask a dark discoloration.

Effect of polymerization mode of two adhesive systems on push-out bond strength of fiber post to different regions of root canal dentin

BACKGROUND

A few studies have investigated the effect of the activation mode of adhesive systems on bond strength of fiber posts to root canal dentin. This study investigated the push-out bond strengths of a glass fiber post to different root canal regions with the use of two adhesives with light- and dual-cure polymerization modes.

MATERIALS AND METHODS

In this in vitro study, 40 maxillary central incisors were decoronated at cement-enamel junction with 15 ± 1 mm root length. After root canal therapy and post space preparations, they were randomly divided into four groups. Post spaces were treated with four different adhesives: Excite, Excite Dual cure Single Component (DSC), self-etch adhesive (AdheSE), and AdheSE dual-cure. Then the fiber-reinforced composite (FRC) post, Postec Plus, was cemented with dual-cure resin cement, Variolink II. The roots were cut into three 2-mm-thick slices. Push-out tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min. The mode of failures was determined under a stereomicroscope. Data were analyzed by three-way analysis of variance (ANOVA) and Tukey test was conducted to compare post hoc with P < 0.05 as the level of significance.

RESULTS

The highest bond strength was obtained for AdheSE dual-cure (15.54 ± 6.90 MPa) and the lowest was obtained for Excite light-cure (10.07 ± 7.45 MPa) and only the bond strength between these two adhesives had significant difference (P = 0.02). Bond strength decreased from the coronal to the apical in all groups and this was significant in Excite (group 1) and AdheSE (group 3) (P < 0.001). In apical regions, bond strength of dual-cure adhesives was significantly higher than light-cure adhesives (P < 0.001).

CONCLUSION

Push-out bond strength of fiber post to different regions of root canal dentin was affected by both adhesive systems and their polymerization modes.

Marginal Sealing of Bulk Fill versus Conventional Composites in Class II Composite Restorations: An In Vitro Study

Objectives: Bulk fill composites are preferred to conventional composites with time-consuming incremental application technique, given that they have good mechanical properties and low microleakage. The aim of this study was to evaluate and compare the dentinal marginal microleakage of bulk fill (in two viscosities) and conventional composites in class II cavities in maxillary premolars. Materials and Methods: In this in vitro studyˏ 42 class II cavities were prepared in the mesial and distal surfaces of 21 maxillary premolars extending 1 mm below the cementoenamel junction, and restored with Grandio composite with 2-mm increments, and X-tra fil and X-tra base with 4-mm increments. After 24 h of storage at 37oC and 100% humidity, they were thermocycled (500 cyclesˏ 5-55oC), stored in basic fuchsine, sectioned, and evaluated under a stereomicroscope (×40). The microleakage scores of the gingival margin were recorded. Statistical analysis was done by SPSS 21 via the Kruskal-Wallis and Mann-Whitney U tests at P≤0.05 level of significance. Results: No statistically significant differences were noted among the groups in marginal microleakage (P=0.47). No statistically significant difference was noted between bulk and incremental application techniques in this respect either (P=0.23). Conclusion: There was no difference in marginal microleakage between the bulk fill and conventional composites.

Parameters affecting degree of conversion of dual-cure resin cements in the root canal: FTIR analysis

OBJECTIVE

To evaluate the degree of conversion of dual-cured resin cements applied for luting of translucent and opaque fibre posts.

METHODS

Two dual-cured resin cements, RelyX ARC and Nexus 2, were used to cement 2 types of tooth-coloured fibre posts, D.T. Light-Post (translucent) and D.T. White-Post (opaque). The degree of conversion for each resin cement was measured. Post-curing polymerization and chemical curing of the cements were also measured. The degree of conversion was measured at various distances (4, 6 and 8 mm) from the tip of the light-curing unit by Fourier transform infrared spectroscopy. The data were analyzed with analysis of variance and post hoc tests (α = 0.05).

RESULTS

The degree of conversion of the dual-cure cements was significantly higher with the D.T. Light-Posts than with the D.T. White-Posts (p < 0.05). No significant difference was observed in the degree of conversion at different depths for the RelyX ARC resin cement in conjunction with the D.T. Light-Posts (p > 0.05). The overall degree of conversion decreased linearly with increasing distance from the light-curing tip. Monitoring of post-curing polymerization and chemical curing revealed no further increase in degree of conversion after 5 minutes (p > 0.05).

CONCLUSION

The translucent fibre posts (D.T. Light-Posts) allowed a significantly higher degree of conversion with dual-cure resin cements than the opaque fibre posts (D.T. White-Posts) because of the light-transmitting property of their optical fibres.

The effect of silane-containing universal adhesives on the immediate and delayed bond strength of repaired composite restorations

BACKGROUND

The repair of composite restorations is considered as a conservative treatment for avoiding the risk of pulp injury, the enlargement of cavity preparation, and excess removal of sound dental structure. The aim of this study was to evaluate the effect of silane-containing adhesives on immediate and delayed shear bond strength (SBS) of repaired composite restorations.

MATERIALS AND METHODS

In this in vitro study, 132 discs of Z350 composite were fabricated and divided into fresh (10 min water storage) and aged (6-month water storage + 2000 thermal cycling). All composite surfaces were roughened and etched, and each group was divided equally into six subgroups: 1 (Single Bond 2), 2 (Single Bond Universal), 3 (Clearfil Universal Bond), 4 (silane + Single Bond 2), 5 (silane + Single Bond Universal), and 6 (silane + Clearfil Universal Bond). The specimens were restored with the same composite, thermocycled, and tested for SBS in a universal testing machine. Data were analyzed using one- and two-way ANOVA, t-test, and post hoc Tukey's tests. P < 0.05 was set as the level of significant.

RESULTS

The highest and lowest SBS (in both fresh and aged groups) were related to Single Bond 2 with silane and Clearfil Universal Bond with silane, respectively. The delayed SBS of Single Bond 2 was significantly higher than universal adhesives (in both with and without silane application) (P < 0.05). Silane had no significant effect on the repair bond strength of Single Bond 2 and Single Bond Universal (P > 0.05), while silane application significantly decreased the delayed SBS of Clearfil Universal Bond.

CONCLUSION

The SBS of Single Bond 2 was significantly better than two other universal adhesives. The SBS of Single Bond Universal was not affected by silane application, while silane had a negative effect on delayed SBS of Clearfil Universal Bond.