Tensile bond strength of sealants following Er:YAG laser etching compared to acid etching in permanent teeth

The effect of the Er: YAG laser on the clinical success of hydrophilic fissure sealant: a randomized clinical trial

Purpose:

The aim of this study was to assess the effect of the Er:YAG laser on the clinical success of a hydrophilic fissure sealant over 12 months.

Subject and methods:

This study was conducted on 132 permanent first molars from 44 (19 girls and 25 boys) patients aged 7-11 years. The teeth were divided into three groups. The first group (Group A-control) of teeth were etched with phosphoric acid, the second group of teeth (Group L) were etched with an Er:YAG laser, and the third group of teeth (Group A+L) were etched with both the Er:YAG laser and phosphoric acid. Clinical evaluations were performed at baseline and at 3-, 6-, 9- and 12-month follow-up visits. The data were analyzed with Pearson chi-square tests, Cochran Q tests and Kaplan-Meier analysis.

Results:

At the end of the 12 months, total retention rates were 72.7%, 59.1%, and 65.9% in the acid group, the laser group and the laser and acid group, respectively. Although there was no statistically significant difference between group retention rates (p>0.05), the lowest retention rate was found in the laser group at the end of the 12-month follow-up period. No new caries were observed in any group during the study period.

Conclusion:

Etching with the Er:YAG laser, phosphoric acid or a combination of both methods provided similar results for the clinical success of hydrophilic based fissure sealant.

Effect of Erbium Laser on Microtensile Bond Strength of Fissure Sealant in Primary Teeth: An in vitro Study

Background:

Laser etching has several advantages as compared with conventional acid etching. However, results of earlier studies on conditioning surfaces with erbium, chromium:yttrium–scandium–gallium–garnet (Er, Cr:YSGG) before application of the fissure sealant have been inconclusive.

Aim:

The study aimed to evaluate the microtensile strength of resin-based fissure sealant bonded to primary enamel conditioned by Er, Cr:YSGG laser with varying power outputs.

Materials and Methods:

Fifty sound primary first molars were randomized into the following five groups based on pretreatment choice: Group 1: 3.5 W laser etching + acid etching; Group 2: 2.5 W laser etching + acid etching; Group 3: 3.5 W laser etching with no acid; Group 4: 2.5 W laser etching with no acid and Group 5: acid etching with no laser. Acid etch was performed with 35% orthophosphoric acid for 30 s. Laser etching was performed with Er, Cr:YSGG (2780 nm) laser using G6 tips and 600 μm diameter, 2.5 W or 3.5 W power outputs, pulse duration of 140 μs and a repetition rate of 20 Hz. Sealant was applied on the buccal surface followed by an incremental buildup with composite resin. Microtensile bond strength was assessed and compared among the five groups using one- and two-way ANOVA.

Results:

There was no statistical difference in the mean bond strength between groups except in Group 4 (9.66 MPa) (Group 1: 15.57 MPa; Group 2: 14.18 MPa; Group 3: 14.78 MPa; Group 5: 14.63 MPa).

Conclusion:

Pretreatment with 3.5 W Er, Cr:YSGG laser alone results in microtensile bond strengths similar to that produced by acid etching, indicating that enamel etching using 3.5 W Er, Cr:YSGG laser would result in the long-term success of pit and fissure sealants in primary teeth.

Assessment of microleakage of class V restored by resin composite and resin-modified glass ionomer and pit and fissure resin-based sealants following Er:YAG laser conditioning and acid etching: in vitro study

Aim

The aim of this study was to make a comparison between microleakage of conventionally restored class V cavities using acid etchant and the ones conditioned by erbium-doped yttrium aluminum garnet (Er:YAG) laser, and also to assess and compare the effectiveness of enamel surface treatments of occlusal pits and fissures by acid etching and conditioned by Er:YAG laser-etch.

Materials and methods

Seventy-two extracted third molars were used in this study. The samples were divided into two major groups: class V cavities and pit and fissure sealants. Each subgroup was divided into conventional acid etching, Er:YAG laser conditioning and conventional acid etching, and combination with Er:YAG laser conditioning (n=12). The teeth were placed in 2% methylene blue dye solution, were sectioned, and were evaluated according to the dye penetration criteria. Two samples per subgroup were chosen for scanning electron microscopic (SEM) analysis.

Results

There was a significant difference between occlusal and cervical margin groups. Laser conventional composite cementum group showed more microleakage values compared to other groups. There was no significant difference between occlusal margin groups. However, there was a significant difference between cervical margin groups in terms of microleakage. In sealant groups, there was a significant difference between laser and conventional with/without laser treatment groups in terms of microleakage.

Conclusion

Based on the results reported in this study, it can be concluded that the application of the Er:YAG laser beneath the resin composite, the resin-modified glass ionomers (GIs), and the fissure sealant placement may be an alternative enamel and dentin etching method to acid etching.

Effect of Ti:sapphire laser on shear bond strength of orthodontic brackets to ceramic surfaces

BACKGROUND AND OBJECTIVES

With increasing demand for orthodontic treatments in adults, orthodontists continue to debate the optimal way to prepare ceramic surfaces for bonding. This study evaluated the effects of a Ti:sapphire laser on the shear bond strength (SBS) of orthodontic brackets bonded to two ceramic surfaces (feldspathic and IPS Empress e-Max) and the results were compared with those using two other lasers (Er:YAG and Nd:YAG) and 'conventional' techniques, i.e., sandblasting (50 µm) and hydrofluoric (HF) acid.

MATERIALS AND METHODS

In total, 150 ceramic discs were prepared and divided into two groups. In each group, the following five subgroups were prepared: Ti:sapphire laser, Nd:YAG laser, Er:YAG laser, sandblasting, and HF acid. Mandibular incisor brackets were bonded using a light-cured adhesive. The samples were stored in distilled water for 24 hours at 37°C and then thermocycled. Extra samples were prepared and examined using scanning electron microscopy (SEM). SBS testing was performed and failure modes were classified. ANOVA and Tukey's HSD tests were used to compare SBS among the five subgroups (P < 0.05).

RESULTS

Feldspathic and IPS Empress e-Max ceramics had similar SBS values. The Ti:sapphire femtosecond laser (16.76 ± 1.37 MPa) produced the highest mean bond strength, followed by sandblasting (12.79 ± 1.42 MPa) and HF acid (11.28 ± 1.26 MPa). The Er:YAG (5.43 ± 1.21 MPa) and Nd:YAG laser (5.36 ± 1.04 MPa) groups were similar and had the lowest SBS values. More homogeneous and regular surfaces were observed in the ablation pattern with the Ti:sapphire laser than with the other treatments by SEM analysis.

CONCLUSIONS

Within the limitations of this in vitro study, Ti:sapphire laser- treated surfaces had the highest SBS values. Therefore, this technique may be useful for the pretreatment of ceramic surfaces as an alternative to 'conventional' techniques.

Microtensile bond strength of a resin-based fissure sealant to Er,Cr:YSGG laser-etched primary enamel

The aim of this study was to evaluate the effect of Er,Cr:YSGG laser pre-treatment alone, or associated with acid-etching, on the microtensile bond strength of a resin-based fissure sealant to primary enamel. Twenty-five human primary molars were randomly divided into five groups including (1) 35 % acid etching, (2) 2.5-W laser etching, (3) 3.5-W laser etching, (4) 2.5-W laser etching + acid etching, and (5) 3.5-W laser etching + acid etching. Er,Cr:YSGG laser was used at a wavelength of 2.780 nm and pulse duration of 140-200 μs with a repetition rate of 20 Hz. Following surface pre-treatment, the fissure sealant (ClinPro™, 3M Dental Products) was applied. Each tooth was sectioned and subjected to microtensile testing. Kruskal-Wallis test was used for statistical analysis. The level of significance was set at p < 0.05. The microtensile bond strength values of group 1 were significantly higher than those of group 2, while no statistically significant difference was detected between groups 1, 3, 4, and 5. It was concluded that 3.5-W laser etching produced results comparable to conventional acid etching technique, whereas 2.5-W laser etching was not able to yield adequate bonding performance.

Self-etch bonding agent beneath sealant: Bond strength for laser-irradiated enamel

OBJECTIVES

This study evaluated the in vitro shear bond strength (SBS) of a resin-based pit-and-fissure sealant (Fluroshield [F], Dentsply/Caulk) associated with either an etch-and-rinse (Adper Single Bond 2 [SB], 3M/ESPE) or a two-step self-etch adhesive system (Adper SE Plus [SE], 3M/ESPE) on Er: YAG laser-irradiated enamel.

MATERIALS AND METHODS

Seventeen sound third molar crowns were embedded in acrylic resin, and the mesial-distal enamel surfaces were flattened. The enamel sites were irradiated with a 2.94-μm wavelength Er: YAG laser (120 mJ, 4 Hz, noncontact mode/17 mm, 20 s). The specimens were randomly assigned to three groups according to the bonding technique: I - 37% phosphoric acid etching + SB + F; II - SE + F and III - F applied to acid-etched enamel, without an intermediate layer of bonding agent. In all of the groups, a 3-mm diameter enamel-bonding site was demarcated and the sealant cylinders were bonded. After 24 hours in distilled water, the shear bond strength was tested at a crosshead speed of 0.5 mm/minute. The data were analyzed by one-way ANOVA and Tukey's test. The debonded specimens were examined with a stereomicroscope to assess the failure modes.

RESULTS

The mean SBS values in MPa were I = 6.39 (±1.44); II = 9.50 (±2.79); and III = 5.26 (±1.82). No statistically significant differences were observed between groups I and III; SE/F presented a significantly higher SBS than that of the other groups (P = 0.001). With regard to the failure mode, groups I (65%) and II (75%) presented adhesive failures, while group III showed 50% adhesive failure. Cohesive failure did not occur.

CONCLUSION

The application of the two-step self-etch bonding agent (Adper SE Plus) beneath the resin pit-and-fissure sealant placement resulted in a significantly higher bond strength for the Er:YAG laser-irradiated enamel.

Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser

CONTEXT

Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching.

AIMS

Evaluate shear bond strength (SBS) values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG) laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values.

SUBJECTS AND METHODS

One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15) and to enamel morphology analysis (n = 5) after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA)+ ExciTE(®); Group II - ExciTE(®); Group III - AdheSE(®) self-etching; Group IV - FuturaBond(®) no-rinse. NR; Group V - Xeno(®) V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min.

STATISTICAL ANALYSIS USED

One-way ANOVA and post-hoc tests (P < 0.05). For the morphology evaluation, specimens were immersed in Ethylenediamine tetraacetic acid (EDTA) and the etching pattern analyzed under Scanning Electron Microscope (SEM).

RESULTS

Mean bond strengths were Group I - 47.17 ± 1.61 MPa (type I etching pattern); Group II - 32.56 ± 1.64 MPa, Group III - 29.10 ± 1.34 MPa, Group IV - 23.32 ± 1.53 MPa (type III etching pattern); Group V - 24.43 MPa ± 1.55 (type II etching pattern).

CONCLUSIONS

Different adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE(®) and ExciTE(®) without condition with PA. FuturaBond(®) NR and Xeno(®) V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.