Repair bond strength and surface topography of resin-ceramic and ceramic restorative blocks treated by laser and conventional surface treatments

Do different protocols affect the success rate or bond strength of glass-ceramics repaired with composite resin? A systematic review and meta-analysis

STATEMENT OF PROBLEM

Intraoral repair techniques prevent unnecessary replacement of ceramic restorations, thereby increasing the survival rate. However, adhesion between ceramics and the composite resin is challenging and how different protocols influence adhesion is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to analyze the influence of different protocols on repairing glass-ceramic surfaces with composite resins.

MATERIAL AND METHODS

PubMed, Scopus, ISI Web of Science, and Embase electronic databases were searched to select studies comparing bond strength values or survival rates of glass-ceramic repaired with composite resins using different surface treatment protocols. No publication year or language restriction was applied. Data sets were extracted from all included studies, and the mean differences calculated. A 95% confidence interval was calculated by using the random effect model (Rev Man 5.4).

RESULTS

The search identified 5037 studies, and 165 were assessed for eligibility. Finally, 123 in vitro studies were included in the systematic review and 48 in the meta-analysis. Considering different glass-ceramics, bond strength tests, and aged or not aged specimens, 37 meta-analyses found the effect of repair protocols: only adhesive, silane plus adhesive alone or preceded by hydrofluoric (HF) acid, airborne-particle abrasion (APA) with Al2O3 particles, silica-coated APA (SCAPA), diamond rotary instrument (DRI), and laser irradiation (LI).

CONCLUSIONS

For feldspathic porcelain, HF acid, APA, SCAPA, or DRI improved the repair micromechanical retention; applying silane is essential to HF-conditioned surfaces but the use of adhesive is optional when silane is applied. Results for leucite and lithium disilicate were inconclusive in terms of suggesting a treatment other than HF acid plus silane and adhesive applications.

The impact of various surface treatments and Er-YAG laser irradiation on the bond strength of resin matrix CAD/CAM ceramics to resin cement

PURPOSE

The aim of the study was to assess the impact of various surface treatments, including an Er: YAG laser with different power outputs, on the shear bond strength (SBS) of different resin matrix CAD/CAM ceramic materials to resin luting cement.

MATERIALS AND METHODS

Specimens from Lava Ultimate (LU) and Vita Enamic (VE) were categorized based on the surface treatment: no treatment, sandblasting (Sb), 10% hydrofluoric acid (Ac) etching, sandblasting followed by acid etching (Sb + Ac), and Er: YAG laser irradiation at 2 W and 3 W (L1, L2). Scanning electron microscopy (SEM) evaluation and roughness measurement of the samples were performed. Silane was applied to half of the specimens, resin cement was bonded and SBS testing was performed.

RESULTS

The SBS did not differ depending on the material (P = 0.081), but varied according to the surface treatment (P < 0.001). The highest mean SBS value was observed in the Sb + Ac (15.20) group. The highest roughness median was in Sb of VE, which was similar to Sb + Ac and Sb of all materials.

CONCLUSION

Applying Sb and Ac together was more effective than applying them separately. Although 2 W and 3 W Er-YAG applications were ineffective for treating VE's surface, 2 W Er-YAG applications can be suggested for LU.

CLINICAL RELEVANCE

The combined application of Sb and Ac is more effective than their individual applications and laser irradiation in terms of resin matrix CAD/CAM ceramics retention.

Effect of surface treatments on the bond strength of resin-repaired resin matrix CAD-CAM ceramic: A scoping review

OBJECTIVE

To evaluate the existing evidence on surface treatment techniques employed in the repair of resin matrix CAD-CAM ceramics and their effects on short- and long-term bond strength.

METHODOLOGY

This scoping review was conducted following the PRISMA-ScR guidelines for scoping reviews and was registered on the Open Science Framework platform. Based on the PCC concept, where P: Resin matrix CAD-CAM ceramic blocks for CAD-CAM, C: Bond strength, and C: Surface treatments, a search was conducted in the PubMed, Embase, Web of Science, Scopus, and Lilacs (grey literature) databases until October 2024, with no language or date restrictions.

RESULTS

In vitro studies comparing mechanical and/or chemical surface treatments on the bond strength of resin composite repairs were included. A total of 47 studies were included in the qualitative analysis, of which 45 used both mechanical and chemical treatments, and 29 used chemical treatments alone.

CONCLUSION

The combination of chemical and mechanical treatments is the appropriate option. Alumina blasting and silica coating are the most commonly used mechanical surface treatments, either alone or in conjunction with chemical treatments. Laser irradiation may serve as an alternative to conventional treatments.

CLINICAL SIGNIFICANCE

The studies revealed variability among protocols for repairing resin matrix CAD-CAM ceramics, with the combined use of chemical and mechanical treatments being the most effective approach.

Optical properties of repaired additively manufactured resin composites and zirconia and subtractively manufactured ceramics: a comparative study of composite resins

OBJECTIVE

This study aims to examine color properties of repairs made with various composites on restorations produced through additive-manufactured resin composites (AM-RC) and zirconia (AM-Z) or subtractive manufacturing (SM) after coffee thermocycling (CTC).

MATERIALS AND METHODS

Disk-shaped specimens (Ø10 × 2 mm; N = 120) were fabricated using six different material groups: additively manufactured resin composite (AM-RC) materials (Crowntec [C], NextDent [ND]), additively manufactured zirconia (AM-Z) materials (Lithoz [LI], INNI-Cera [IN]), and subtractively manufactured (SM) materials (CEREC Tessera [ALD], Vita Enamic [EN]). Subsequently, each group was further subdivided into two subgroups (n = 10) based on the type of repair using two different composites resins: Clearfil Majesty Posterior (CL) (n = 60) and Filtek Z350 (FZ) (n = 60). Specimens underwent thermal cycling (CTC), consisting of 10,000 cycles between 5 °C and 55 °C. Color measurements were performed both before and after thermal cycling for all materials. Color discrepancies (ΔE00) and relative translucency parameters (RTPs) were calculated. Statistical analyses were conducted at a significance level of α = 0.05.

RESULTS

A one-way ANOVA of ΔE00 values between CL and FZ revealed a significant difference (P = 0.007), with FZ exhibiting higher ΔE00 values. Significant differences in ΔE00 values were also observed among IN, C, and ND after CTC (P < 0.05). ALD demonstrated the lowest amount color change (P < 0.05). LI and EN colors showed no significant difference (P = 0.75). Following CTC, C, ND, and IN colors matched CL. In contrast, ALD, EN, and L colors exhibited significant differences (P ≤ 0.050). FZ showed a poor color match with all AM and SM materials. Furthermore, significant differences in RTP values were identified for all specimens (P < 0.001), with LI having the highest RTP and IN the lowest (P < 0.001).

CONCLUSION

The optical properties of composite and ceramic materials, as well as their stability over time, are crucial for their durability. ALD demonstrated the most consistent color stability. While the CL repair composites experienced some color changes, these changes remained within acceptable limits. Additionally, the LI (AM-Z) material exhibited the highest level of translucency.

Repair protocols for indirect monolithic restorations: a literature review

Despite the advancements in indirect monolithic restorations, technical complications may occur during function. To overcome this issues, intraoral repair using resin composite is a practical and low-cost procedure, being able to increase the restoration's longevity. This review aimed to evaluate the need for repair and suggest a standardized repair protocol to the main indirect restorative materials. For this, studies were surveyed from PubMed with no language or date restriction, to investigate the scientific evidence of indirect monolithic restoration repair with direct resin composite. A classification to guide clinical decisions was made based on the FDI World Dental Federation criteria about defective indirect restorations considering esthetic and functional standards, along with the patient's view, to decide when polishing, repairing or replacing a defective restoration. Based on 38 surveyed studies, different resin composite intraoral repair protocols, that included mechanical and chemical aspects, were defined depending on the substrate considering resin-based, glass-ceramic or zirconia restorations. The presented criteria and protocols were developed to guide the clinician's decision-making process regarding defective indirect monolithic restorations, prolonging longevity and increasing clinical success.

The Effect of Laser Irradiation to Surfaces of Computer-Aided Design/Computer-Aided Fabrication Resin Blocks Coated with a Silane Coupling Agent on Bond Strength between the Resin Blocks and Composite Resin

The aim of this study was to investigate the effect of laser irradiation to computer-aided design/computer-aided fabrication (CAD/CAM) resin blocks coated with a silane coupling agent on the bond strength between resin blocks and composite resin. The CAD/CAM resin blocks used in this study were Cerasmart 300 (GC) and Vita Enamic (Vita); they were cut into plates and then subjected to a series of treatments. After processing with a silane coupling agent, treatment with a semiconductor laser was performed at 3.0, 5.0, and 7.0 W, followed by bonding procedures. The control group included those exposed to silane and bonded without laser application. After bonding, a mold with a simulated cavity was formed on the specimen and filled with flowable composite resin, and they were stored for 24 h or stressed by thermal cycling for subsequent testing that assessed the shear bond strength (n = 10). The results revealed that the bond strength was significantly enhanced by laser irradiation after applying a silane coupling agent (p < 0.03), whereas significant increase was not detected between the materials (p > 0.05). Particularly, 7 W laser irradiation had a significant increase on the bond strength between the composite resin and Cerasmart block after thermal cycling (p = 0.009). The SBS of the composite resin to CAD/CAM resin blocks was significantly enhanced by laser irradiation after silane coupling agent application.

Evaluation of repair bond strength of a dental CAD/CAM resin composite after surface treatment with two Er,Cr:YSGG laser protocols following artificial aging

The aim of the present study was to evaluate the impact of two Er,Cr:YSGG laser surface treatments on the repair bond strength of a dental CAD/CAM resin composite (Brilliant Crios) after artificial aging. Twenty-four resin-based CAD/CAM blocks were cut and 48 rectangular slabs (3 x 12 x 14 mm) were prepared. Preliminary SEM observations indicated the most favorable laser settings regarding surface modification of the tested restorative material. The CAD/CAM specimens were then divided into 4 groups (n=12) based on their surface pretreatment: no treatment, air abraded with 50-μm Al2O3 particles, and laser irradiated with two different protocols using Er,Cr:YSGG laser with average power 3.5 and 4.5 W, pulse repetition rate 35 and 50 Hz, and pulse energy 100 and 90 mJ, respectively. After surface treatments each group followed a bonding protocol with silane and a flowable resin composite was used to prepare 48 microrods. Half of the microrods of each group were subjected on shear bond strength (SBS) test (chisel-shaped blade, load cell of 500 N, crosshead speed of 1 mm/min) after 24 h, while the other half underwent artificial aging (15,000 cycles, 5-55 °C) and then SBS test. The debonded specimens were examined under an optical microscope to determine the failure mode. All specimens were also evaluated using SEM to assess the surface topography after the treatments. The results showed that SBS significantly decreased after thermocycling in all the experimental groups (p<0.05). Control group presented much lower SBS values than the other groups after both 24 h and thermocycling (p<0.05). The highest values of SBS exhibited air-abrasion group (p<0.05), followed by the two laser groups, which did not differ to each other (p>0.05). The results of the current study indicated that Er,Cr:YSGG laser irradiation can be an alternative treatment for repairing the tested resin-based CAD/CAM restorative material.

Hybrid ceramic repair strength, surface roughness, and bond failure, using methylene blue-activated low-level laser therapy, Carbon dioxide, and Ti: Al2O3 laser

AIMS

To evaluate the impact of various pretreatment regimes (LLLT, Ti-sapphire laser, CO2, and HFA-S) on hybrid ceramics, specifically focusing on their ability to enhance repair strength and minimize surface roughness (Ra).

MATERIAL AND METHODS

Discs were made from hybrid ceramics and after disinfection were randomly divided into four groups based on different surface conditioning techniques. Each group consisted of 15 discs, resulting in a total sample size of 60. dics in group 1 was surface treated with Low-level laser therapy (LLLT) using methylene blue (MB), Discs in group 2 with Ti-sapphire laser, Discs in group 3 with CO2 laser, and discs in group 4 with HFA-S. Five samples from each group were assessed for Ra. The remaining 10 samples from each group underwent repair using a porcelain repair kit in adherence to the planned instructions. The bond strength of each sample in all groups was measured using a universal testing machine. Following the bond strength testing, the specimens from all study groups were analyzed to determine the mode of failure. To evaluate the data, a two-way analysis of variance (ANOVA) was used, followed by post hoc multiple comparisons.

RESULTS

The highest repair bond strength was observed in group 4 hybrid ceramics pretreated with HFA-S (19.05±0.79 MPa). The lowest repair bond scores were observed in group 1 hybrid ceramics preconditioned with LLLT in the presence of Photosensitizer (13.41±0.36 MPa). The highest Ra scores were exhibited in group 2 surface treated with Ti-sapphire laser (0.0515±0.16 µm) and the lowest Ra scores were observed in Group 4 HFA-S (0.0311±0.79 µm). Predominant bond failure among different investigated groups was cohesive.

CONCLUSION

The current gold standard for hybrid ceramic conditioning is the use of hydrofluoric acid (HFA) combined with a silane coupling agent. Low-level laser therapy with methylene blue photosensitizer is not recommended for the treatment of hybrid ceramics.

Effect of Different Surface Treatments on Repair Bond Strength of CAD/CAM Resin-Matrix Ceramics

The purpose of this study was to investigate the influence of different surface treatment methods on the micro-tensile bond strength (μTBS) of resin-matrix ceramic (RMC) blocks repaired with resin composite. Three different prefabricated RMC blocks including Lava Ultimate (LU), Grandio Blocs (GB), and Shofu Block HC (HC) were thermo-cycled and divided into five surface treatment groups: Control (C), bur grinding (G), airborne particle abrasion (APA), Er,Cr:YSGG laser irritation (LI), and APA combined with LI (APA+LI). After surface treatments, topographic alterations were examined by scanning electron microscopy. Then, Universal Adhesive (Single Bond Universal) was applied and repair was simulated with nanohybrid composite (Grandio SO). Bonded specimens were cut into 1 mm2 sized beams (n = 16) and a μTBS test was conducted by using a universal test machine. Fracture types were evaluated by using a stereomicroscope. The bond- strength data was evaluated by two-way ANOVA and Tukey post-hoc test (α = 0.05). The μTBS values were significantly affected by the surface treatment variable and the interaction terms of the variables (p ≤ 0.001). However, no significant effect of RMC type was detected (p > 0.05). Among all materials, GBAPA+LI indicated the highest µTBS value. Except for the GBC, all surface treatments showed clinically acceptable bond-strength values. However, the surface treatments applied to GB and LU before the repair processes increased the repair bond-strength values while causing a negative effect for HC. In addition, LI and APA+LI can be applied as an alternative route compared to other procedures recommended by the manufacturer for surface preparation in intraoral RMC repair.