Accelerated silicosis in sandblasters: Pathology, mineralogy, and clinical correlates.

BACKGROUND: With increasing reports of accelerated and acute silicosis, PMF, and autoimmune disease among coal miners and silica-exposed countertop workers, we present previously incompletely-described pulmonary pathology of accelerated silicosis and correlations with mineralogy, radiography, and disease progression in 46 Texas oilfield pipe sandblasters who were biopsied between 1988 and 1995. METHODS: Worker examinations included pulmonary function tests, chest X-ray (CXR), high-resolution computed tomography (HRCT), and Gallium-67 scans. Quantitative mineralogic analysis of pulmonary parenchymal burden of silica, silicates, and metal particles used scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM EDS). RESULTS: Workers had clinical deterioration after <10 years exposure in dusty workplaces. Although initial CXR was normal in 54%, Gallium-67 scans were positive in 68% of those with normal CXR, indicating pulmonary inflammation. The histology of accelerated silicosis is diffuse interstitial infiltration of macrophages filled with weakly birefringent particles with or without silicotic nodules or alveolar proteinosis. Lung silica concentrations were among the highest in our database, showing a dose-response relationship with CXR, HRCT, and pathologic changes (macrophages, fibrosis, and silicotic nodules). Radiographic scores and diffusing capacity worsened during observation. Silica exposure was intensified, patients presented younger, with shorter exposure, more severe clinical abnormalities, higher lung particle burdens, and more rapid progression in a subset of patients exposed to recycled blasting sand. CONCLUSIONS: Accelerated silicosis may present with a normal CXR despite significant histopathology. Multivariable analyses showed silica, and not other particles, is the driver of observed radiologic, physiologic, and histologic outcomes. Eliminating this preventable disease requires higher physician, public health, and societal awareness.

Effect of different surface treatments and adhesive cementation on the surface topography and flexural strength of translucent and ultra-translucent monolithic zirconia.

PURPOSE: To evaluate the effect of different surface treatments and adhesive cementation on the miniflexural strength (MFS) of monolithic zirconia. MATERIALS AND METHODS: Two-hundred and forty (240) sintered bars of translucent zirconia (ZT) and ultra-translucent zirconia (ZUT) were obtained (8 mm ×2 mm ×1 mm). The bars were divided into 16 groups (n = 15) according to the factors "Zirconia" (ZT and ZUT), "Cementation" (Cem) and "surface treatment" (Ctrl:Control, Al:Aluminum oxide/Al2O3 50 µm, Si:Silica/SiO2 coated alumina particles oxide 30 µm, Gl:Glazing+hydrofluoric acid). Half of the bars received an adhesive layer application, followed by application of resin cement and light curing. The surface roughness was measured in non-cemented groups. All the bars were subjected to the MFS test (1.0 mm/min; 100 kgf). Scanning electron microscopy was used for qualitative analyses. MFS data (MPa) and roughness (µm) were statistically evaluated by three-way and two-way ANOVA respectively and Tukey's test (5%). RESULTS: The surface treatment and the interaction were significant for roughness. Glazing promoted less roughness compared to silicatization. Regarding MFS, only the zirconia and surface treatment factors were significant. For ZT, the sandblasted groups had an increase in MFS and glazing reduced it. There was no difference between the groups without cementation for the ZUT; however, ZUT.Si/Cem, and ZUT.Al/Cem obtained superior MFS among the cemented groups. CONCLUSIONS: Sandblasting increases the flexural strength for ZT, while glaze application tends to reduce it. Applying resin cement increases the flexural strength of ZUT when associated with sandblasting. Sandblasting protocols promote greater surface roughness.

Effect of Various Surface Treatments of Zirconia on its Adhesive Properties to Dentin: An In Vitro Study.

AIM: To assess the effectiveness of various surface treatments and adhesives on the bond strength of zirconia-based ceramic to dentin. MATERIALS AND METHODS: Eighty samples of zirconia were subjected to the four-surface treatment protocols (sandblasting, 48% hydrofluoric acid (HF), 48% hydrofluoric acid + 70% nitric acid (HNO3) and no treatment (control) following which the samples from each group were subdivided into two subgroups (n = 10) based on the resin cement employed for cementation (RelyX U200 and G-Cem Linkforce). The bonded specimens were subjected to shear stress to measure the bond strength using Universal testing machine. To test the difference in bond strength among the eight study groups, the Kruskal-Wallis ANOVA test was applied and for comparison between cements in each group, Mann-Whitney U test was applied. RESULTS: The highest bond strength values were observed for 48% HF group cemented with G-Cem Linkforce resin cement (16.220 ± 1.574) and lowest for control group-RelyX (4.954 ± 0.972). G-Cem cement showed higher bond strength than RelyX for all surface treatments except 48% HF + 70% nitric acid. CONCLUSION: It can be inferred that 48% HF can etch zirconia and generate a porous structure that proves to be beneficial for bonding. CLINICAL SIGNIFICANCE: The increasing demand for esthetics has led to the replacement of metal-ceramic materials with zirconia-based ceramics. However, the chemical inertness of zirconia to various conventional surface treating agents has continuously challenged researchers to discover a new surface treatment protocol that could enhance the bond strength of zirconia. How to cite this article: Yenamandra MS, Joseph A, Singh P, et al. Effect of Various Surface Treatments of Zirconia on its Adhesive Properties to Dentin: An In Vitro Study. J Contemp Dent Pract 2024;25(3):226-230.

In vitro comparative study between adhesion forces obtained on zirconia ceramic micromechanically treated with femtosecond laser (1027 nm), carbon dioxide laser (10,600 nm), and aluminum-oxide particles.

Conventional surface roughening treatments used for silica-based ceramics in order to improve subsequent adhesion become unreliable for zirconia ceramics. Laser conditioning can be a good alternative. The purpose of this in vitro study was to compare conventional (macro) shear bond strength (SBS) values obtained between resin composite and zirconium oxide ceramic samples grouped according to different micromechanical treatments received, and examine differences in surface roughness. One-hundred and fifty disks of sintered zirconia were randomly divided into 5 groups and roughened as follows: (1) Group NOT, no surface treatment; (2) Group APA, abraded with 50-µm aluminum-oxide (Al2O3) particles; (3) Group TBS, abraded with 30-µm aluminum-oxide particles covered with silica; (4) Group CO2, irradiated with a CO2 laser which emitted in continuous wave mode at 3 W of power; and (5) Group FEM, irradiated with a pulsed femtosecond laser, with an incident energy of 10 µJ, a frequency of 1000 Hz, and a fluence of 1.3 kJ/cm2. All surfaces were treated with a MDP-containing adhesive/silane coupling agent mixture upon which were prepared and light polymerized composite resin cylinders. Shear bond strength was measured and samples were observed by scanning electron microscopy (SEM). Statistically significant differences (p < 0.05) were found among all groups, except between CO2 and FEM, which showed the highest adhesion values (15.12 ± 2.35 MPa and 16.03 ± 2.73 MPa). SEM revealed differences in surface patterns. CO2 laser irradiation can be an alternative to sandblasting, although it could also weaken the ceramic. Suitable surface patterns on zirconia ceramics can be obtained with ultrashort pulsed radiation emitted by a pulsed femtosecond laser.

Long-term follow-up of young denim sandblasters in Turkey.

BACKGROUND: Denim sandblasting-induced silicosis is a recently identified occupational disease. AIMS: In this study, we aimed to evaluate pulmonary and radiological changes in the long-term follow-up of former denim sandblasters. METHODS: Ninety former denim sandblasters were followed from 2007 to 2018. Chest X-rays were evaluated according to the International Labour Organization (ILO) classification. Baseline and final data were compared. Silicosis prevalence, radiological progression and pulmonary dysfunction were evaluated. RESULTS: All of the sandblasters were men. Their mean age was 34 ± 5 years, mean follow-up time was 9 ± 2 years (mean time since initial exposure: 17 ± 2 years) and mean duration of exposure was 34 ± 25 months. Rates of radiological progression and decline in pulmonary during follow-up were 63% and 39%, respectively. During follow-up, all patients were diagnosed with silicosis. All workers who were ILO category 0 at baseline (n = 26, 29%) progressed to higher categories. The number of patients in Category 2 doubled and the number of patients in Category 3 increased by 2.5-fold. Eleven patients developed new large opacities and the number of patients with category C opacity increased from 4 to 13. Exposure time was an independent determinant of radiological progression (OR: 1.0, P = 0.036) and decline in pulmonary function (OR: 1.3, P = 0.019). CONCLUSIONS: The prevalence of silicosis in denim sandblasters increases steadily even after exposure is discontinued. Radiological progression was observed in a higher proportion of workers than a decline in lung function. Duration of exposure was the major determinant of disease progression in our study.

Effect of sandblasting and/or priming treatment on the shear bond strength of self-adhesive resin cement to CAD/CAM blocks.

The aim of this study was to investigate the effect of two different priming agents and/or sandblasting on the shear bond strength of self-adhesive resin cement to the resin composite for core build-up to CAD/CAM blocks. A CAD/CAM ceramic block (GN I CERAMIC BLOCK, GC) and a CAD/CAM resin composite block (CERASMART 270, GC), a self-adhesive resin cement (G-CEM ONE, GC) and two different primers, i.e., a multipurpose primer (MP; G-Multi Primer, GC) and a ceramic primer (CP; Ceramic Primer II, GC), were examined. Five different surface treatments with priming and/or sandblasting and no surface treatment (control) were performed on the block. Disk specimens (6 mm in diameter and 4 mm in thickness) made from core composites were cemented to the blocks after the surface treatments. Then, the 24-h shear bond strength of the resin cement between the block and the resin composite core was determined (n = 15). Sandblasted specimens had greater bond strength than controls for both blocks (p < 0.05). Priming to both blocks significantly increased the bond strength of resin cement compared to that of controls (p < 0.05). Although Weibull moduli were not significantly changed among all surface treatments for both blocks, the strengths with 5% and 95% failure probability of sandblasted and/or primed blocks were estimated to be greater than those of controls. The combination of priming and sandblasting to the CAD/CAM composite and ceramic surface was effective in increasing the bond strength of the resin cement.

Comparative Analysis of Three Surface Treatments on the Bond Strength of Zirconia to Resin-luting Agents: An In Vitro Study.

AIM: To study the impact of three different surface treatments namely sandblasting, silane-coupling agent, and laser on the retention of zirconia prosthesis and bond strength of zirconia to a resin-luting agent. MATERIALS AND METHODS: Sixty zirconia crowns were fabricated and were divided into four groups of 15 samples each on the basis of surface treatments. A control group with no surface treatment (group A), laser-treated (group B), treatment with silane-coupling agent (group C), and sandblasting with aluminium oxide (Al2O3) particles (group D). Testing was then carried out using a universal testing machine (0.5 mm/min crosshead speed). At a point where the crown got separated from the tooth, the reading in kilogram force (kgF) was recorded. The data were collected and analyzed statistically. RESULTS: Group D produced the highest mean bond strength (17.5233 kgF) followed by group B (10.0067 kgF), group C (8.6907 kgF), and group A (3.3773 kgF). One-way ANOVA test showed a p-value more than 0.05, concluding no significant difference among the groups. Tukey's HSD post hoc test gave the p-value corresponding to the F-statistic of one-way ANOVA lower than 0.01 when intergroup comparison was done confirming a significant difference among the groups. CONCLUSION: The bond strength significantly increased in the samples treated by sandblasting compared with those treated with laser and silane-coupling agents. CLINICAL SIGNIFICANCE: The success of a zirconia prosthesis lies on its bonding with the tooth structure. Bond failure leads to loss of function and hence ends up in failure. Selection of the proper surface treatment will not only improve the bond strength but also amplify the retention of zirconia-based prosthesis, thereby reducing the failure of the final prosthesis. It also improves the longevity of the prosthesis and restores the lost function which is the basic clinical aim of a prosthodontic treatment.

Immediate dentin sealing: effect of sandblasting on the layer thickness.

OBJECTIVES: The objective of this study was to observe and to measure the impact of corundum sandblasting on the thickness of the Immediate dentin sealing layer. METHODS: 20 recently extracted molars were collected and divided randomly into two groups. A standardized preparation was performed on each tooth and the Optibond FL dentin bonding agent (Kerr, Orange, USA) was applied on the prepared surface according to the manufacturer's instructions. The surface was then partially sandblasted. RONDOflex plus 360 (KaVo, Bieberach an der Riss, Germany) and Airsonic Mini-Sandblaster (Hager et Werken, Duisburg, Germany) were used. Microscope observations were made. RESULTS: The arithmetic mean of the Optibond FL dentin bonding agent film thickness was 48.72 µm (Group 1=45.55 µm and Group 2=51.88 µm). The dentin bonding agent layer thickness was reduced to the average value of 17,12 µm by RONDOflex plus 360 sandblasting (Group 1). The zero value was recorded in 16 % of the locations. The Airsonic Mini-Sandblaster sandblasting changed the average thickness of the dentin bonding agent layer to 13.25 µm with 31 % of zero values (Group 2). CONCLUSION: The results of this research lead to a reflection on modifications of the immediate dentin sealing procedure (Tab. 4, Fig. 3, Ref. 28).

Repair potential of a bulk-fill resin composite: Effect of different surface-treatment protocols.

This study evaluated the effect of different surface-treatment protocols on the repair bond strength of a bulk-fill resin composite. One-hundred and forty specimens (Filtek Bulk-fill) were created (5 mm diameter, 4 mm depth) and allocated to one of 14 groups according to surface treatment (no treatment, tribochemical silica coating, sandblasting with aluminum oxide), adhesive application (no adhesive, total-etch, self-etch), and type of repair resin (bulk-fill, universal resin) (n = 10 per group). Twenty specimens were selected for measuring the cohesive strengths of non-aged resin composites and used as reference. Other specimens were thermocycled. Shear bond-strength testing was performed. Data were analyzed using linear regression of bond strength as a function of the surface treatment, type of adhesive and whether or not adhesive was applied, and type of repair resin. The failure modes were analyzed using logistic regression of failure mode (cohesive failure vs. other types, or adhesive failure vs. other types) on the type of surface treatment, adhesive application, and repair resin used. Surface treatment, regardless of whether this was tribochemical silica coating (mean difference = 5.44 MPa; 95% CI = 4.77-6.11) or sandblasting with aluminum oxide (mean difference = 4.22 MPa; 95% CI = 3.55-4.88), resulted in higher shear bond strength than no treatment. Application of adhesive resulted in a substantial and statistically significant decrease of shear bond strength (by 8.77 MPa, for self-etch and by 7.26 MPa for total-etch) relative to no adhesive. Conversely, the type of repair resin did not influence the shear bond strength to any appreciable extent.

The lingual enamel morphology and bracket shear bond strength influenced by Nd:YAG laser and aluminum oxide sandblasting preconditioning.

OBJECTIVES: This study aimed to investigate the influence of Nd:YAG laser and aluminum oxide sandblasting on the shear bond strength (SBS) of lingual brackets and to optically analyze the behavior of the enamel morphology. MATERIALS AND METHODS: Thirty-five bovines' incisors teeth were divided into 5 groups (n = 7), according to the surface preconditioning: G1, control group; G2, Nd:YAG laser; G3, laser + aluminum oxide sandblasting (Al2O3); G4, Al2O3; and G5, Al2O3 + laser. All groups had lingual brackets bonded and shear debonded after 72 h. SBS values were analyzed, and the enamel morphology was evaluated by optical coherence tomography (OCT) and scanning electron microscope (SEM), before and after preconditioning surface. The optical attenuation coefficient (α) analysis was obtained from OCT images. Data analysis used the ANOVA test, followed by post hoc Tukey, Kruskal Wallis, and post hoc Dunn tests (significance of 5%). RESULTS: The SBS values presented similarly among groups, but the value of α showed statistical difference (p-value = 0.0124) between G3 and G5 with the others. Optical analyses indicated a melting on the enamel that suffered laser irradiation for G2 and G5 and crystal surface disorganization for G4. Sandblasting partially removes the melting of the laser effect (G3). CONCLUSION: The sandblasting is a dispensable step for bonding lingual brackets, and the melting of the enamel after laser irradiation does not compromise the bracket adhesive resistance. CLINICAL RELEVANCE: The Nd:YAG laser became an interesting tool to prevent caries and decrease prevalence of white spot lesions in orthodontic treatments, without systemic effects in patients with genetic high risks of caries.

[Study on the effectiveness of silicon dust prevention and control of small sandblasting cabinet type water curtain exhaust hood].

Objective: To explore the effect of cabinet type water curtain exhaust hood applied to small sandblasting machine to prevent and control silicon dust, and put forward a new idea of dust ventilation protection facilities to effectively protect the occupational health of workers. Methods: From August to October 2018, the cabinet type water curtain exhaust hood of sandblasting room in a research institute was selected as the research object, and the methods of occupational health survey, on-site detection and physical simulation of air distribution were used to conduct on-site detection and smoke emission test on the local exhaust facilities, silica dust concentration, control wind speed and air distribution before and after the transformation line analysis and evaluation. Results: The air distribution simulation experiment showed that the air distribution of the cabinet type water curtain exhaust hood was reasonable and could effectively control the whole range of silica dust emission during the cleaning process. After modification, the capture velocity was increased from 0.01 m/s to 0.53 m/s, and the capture velocity was increased by 98.1%. The time weighted average allowable concentration (C(TWA)) of silicon dust (total dust) during sand blasting, cabin opening and cleaning was reduced from 7.00 mg/m(3) to 0.50 mg/m(3). The C(TWA) of silica dust (exhalation dust) was decreased from 3.36 mg/m(3) to 0.27 mg/m(3), and the C(TWA) dust reduction rates of total dust and respirable dust were 92.9% and 92.0%, respectively. Conclusion: The combination of cabinet type exhaust hood and water curtain dedusting optimizes the combination mode of dust prevention and control. It has the advantages of high efficiency of dedusting and purification, energy saving and environmental protection, and can be popularized and used in enterprises of the same nature.

Debranching-first and proximal arch replacement for an innominate artery aneurysm: a case study.

The aneurysms of the innominate artery represent a rare form of aneurysmal disease. Management in an early elective basis is recommended due to the risk of stroke and rupture. Treatment options include open surgery, which is the gold standard, and endovascular repair. We describe the debranching-first technique and proximal arch replacement for a huge innominate artery aneurysm and discuss the surgical strategy for cannulation, perfusion and organ protection.

Bond Strength Durability of Adhesive Cements to Translucent Zirconia: Effect of Surface Conditioning.

PURPOSE: To evaluate the influence of airborne particle abrasion, Piranha acid and hot acid etching on bond strength of zirconia with self-adhesive resin cements after aging. Also, the effect of Silano-Pen treatment on the bond strength of zirconia to resin cements. MATERIALS AND METHODS: Thirty-six zirconia blocks were cut, sintered and divided into three groups (n=12); Airborne particle abrasion, Piranha acid, and hot acid etching were then treated with Silano-Pen. Each zirconia block was bonded to its corresponding composite block utilizing either Panavia SA, TheraCem or Panavia F2.0. 360 micro -tensile test bars were obtained and half of them were subjected to 10000 thermal aging cycles. Each microtensile test bar was subjected to microtensile force until debonding. Scanning Electron Microscopic evaluation was performed. RESULTS: There was a significant difference between the surface treatments. Hot acid showed the highest mean bond strength and the lowest was Piranha acid. Panavia SA significantly improved the bond strength compared to TheraCem and Panavia F2.0. The interaction between cement and Silano-Pen was non-significant (p=.067). Under SEM analysis, hot acid treatments showed homogenous granular texture with wide distribution of porous network. CONCLUSIONS: Pre-treatment, resin cement, and aging influences the effectiveness of bonding of zirconia. Silano-Pen after hot acid improved the bonding of zirconia.

The influence of enamel sandblasting on the shear bond strength and fractography of the bracket-adhesive-enamel complex tested in vitro by the DIN 13990:2017-04 standard.

OBJECTIVES: This study was conducted in order to investigate whether enamel sandblasting as an adjunct or substitute to the acid-etch technique has an effect on the shear bond strength (SBS) and fractography of the bracket-adhesive-enamel complex using the DIN 13990:2017-04 standard. MATERIALS AND METHODS: Upper central incisor brackets (discovery®, Dentaurum, Germany) were bonded using Transbond XT™ (3M Unitek, Germany) on bovine incisors prepared by four different methods (15 samples each): sandblasting with 27 µm Al2O3 at 1.2 bar (s), acid etching with 37.4% phosphoric acid (a), sandblasting with 27 µm Al2O3 at 1.2 bar followed by acid etching (s1a), and sandblasting with 50 µm Al2O3 at 5.7 bar followed by acid etching (s2a). The SBS and adhesive remnant index (ARI) were measured, followed by one-way analysis of variance and Fisher's exact tests at 5%. RESULTS: The SBS in groups s (5.6 ± 2.2 MPa), a (17.1 ± 4.3 MPa), s1a (18.3 ± 4.3 MPa), and s2a (18.5 ± 4.6 MPa) indicated that the s group was significantly inferior to all the other groups (p < 0.001). Likewise, the ARI analysis indicated a different performance of the s group (mostly ARI of 0) compared to the other groups (p < 0.001) and a tendency for different ARI between the a and s1a/s2a groups. CONCLUSIONS: In vitro enamel sandblasting could not substitute acid etching and did not offer improved SBS when used before acid etching, regardless of air pressure and powder granulation. Sandblasting without acid etching produced less residual resin on the tooth after debonding. CLINICAL RELEVANCE: The clinical use of adjunct enamel sandblasting prior to etching to enhance SBS has to be questioned.

Effect of selective infiltration etching on the bond strength between zirconia and resin luting agents.

OBJECTIVE: To evaluate the shear bond strength of resin cements to zirconia treated with the selective infiltration etching technique (SIE). MATERIALS AND METHODS: Forty-seven zirconia specimens were prepared with a sequence of silicon carbide abrasives, cleaned in an ultrasonic bath. Three samples were separated for atomic force microscope (AFM) analyses (one nontreated for control, one sandblasted, and one selective infiltration etched) and the remaining were randomly distributed in four groups, according to the combination of surface treatment and resin cement: group 1a (sandblasting + Variolink II), group 1b (sandblasting + Panavia SA Plus), group 2a (SIE + Variolink II), group 2b (SIE + Panavia SA Plus). A composite resin cylinder (3 mm × 3 mm) was cemented to the zirconia surface, as per each group's specific protocol. After storing 24 hours in distilled water at 37°C, the specimens were tested for shear bond strength and the results were subjected to statistical analysis. RESULTS: At 24 hours, the highest SBS values were observed in group 2b, where the SIE technique was used in conjunction with Panavia SA Plus. Lowest values were found in group 1a. Increased surface roughness was observed with SIE. CONCLUSIONS: SIE significantly enhanced the resin bond strength to zirconia. However, cement selection was also an important factor, for both surface treatments tested. CLINICAL SIGNIFICANCE: Use of SIE method combined with MDP monomer containing resin cement can provide clinically acceptable bond strength between zirconia and resin cement.

Microtensile Bond Strength of CAD/CAM Resin Blocks to Dual-Cure Adhesive Cement: The Effect of Different Sandblasting Procedures.

PURPOSE: To investigate the effect of sandblasting powder particles on microtensile bond strength (µTBS) of dual-cure adhesive cement to CAD/CAM blocks. MATERIALS AND METHODS: CAD/CAM blocks (Cerasmart, VITA, and LAVA) were cut in slabs and divided into groups: group 1, no sandblasting; group 2, sandblasted with 27-µm Al2 O3 ; group 3, sandblasted with 30-µm CoJet; group 4, sandblasted with 50-µm Al2 O3 . After sandblasting, all specimens were silanized and luted using dual-cure adhesive cement (G-CEM LinkForce). After 24 hours, bonded specimens were cut into 1 ± 0.2 mm2 sticks, and µTBS values were obtained (N = 30). Additionally, 132 CAD/CAM block sections were prepared for surface roughness testing and scanning electron microscopy (SEM) evaluations. Results were analyzed using Kruskal-Wallis One-way ANOVA and Dunn's Post Hoc Test (p < 0.05). RESULTS: Group 1 exhibited significantly lower µTBS than the other groups (p < 0.05). The highest bond strength values were obtained from group 4 (p > 0.05). For LAVA, µTBS values of specimens that were sandblasted with 50-µm Al2 O3 powder were significantly higher than 30-µm-SiO2 and 27-µm Al2 O3 (p < 0.05). CONCLUSIONS: The sand particles investigated (27-µm Al2 O3 , 30-µm SiO2 , or 50-µm Al2 O3 ) did not significantly affect µTBS results of CAD/CAM blocks for Cerasmart and VITA, although the results changed significantly for LAVA. The ideal bond protocol for CAD/CAM blocks is specific to the material used.

Effect of Surface Pretreatment and Thermal Activation of Silane Coupling Agent on Bond Strength of Fiber Posts to Resin Cement.

INTRODUCTION: For the restoration of grossly decayed root canal treated teeth, posts are used frequently to retain core for the definitive restoration. Therefore, it is necessary to create adequate adhesion at the post-root-cement interface for long-term performance of a post retained restoration. AIM: To establish the outcome of surface pretreatments such as silanization, sandblasting, and silanization followed by thermal activation of fiber posts on bonding with a dual-cured adhesive resin-based cement. MATERIALS AND METHODS: Eighty radiopaque, No #2 glass fiber-reinforced epoxy resin posts (Hi-Rem Posts, Overfibers, Switzerland), posts were wiped with alcohol (surgical spirit, 90% alcohol) for 5 seconds in a single stroke. A cylindrical plastic cap of diameter 10 mm and length of 15 mm, which is closed on one side, was selected. This was duplicated to form molds and fiber posts embedded perpendicularly in the polyester resin, and samples were made. Samples were randomly distributed into four groups based on the pretreatment done and each group contains 20 samples, group I-(control), group II-(silanization), group III-(sandblasting), and group IV-(thermal treatment of silane). After surface treatment, exposed post surface was uniformly coated with dual-cured resin cement. Cement was cured for 40 seconds with a halogen lamp. The samples are subjected to load in a universal testing machine (UTM) at a crosshead speed of 1.0 mm/minutes to evaluate the bonding failure at the interface. RESULTS: Group IV resulted in the highest bond strength values followed by group III. Group II showed a comparatively higher value than group I but less than groups III and IV. CONCLUSION: Surface treatment procedure, on fiber post by silanization and sandblasting significantly improved adhesion between post and luting cement interface. CLINICAL SIGNIFICANCE: The surface pretreatment, such as sandblasting, silanization, thermal activation of silane coupling agents significantly improved, the retention of the post within in the root canal system. How to cite this article: Archana CH, Raju SMK, Yadhav SS, et al. Effect of Surface Pretreatment and Thermal Activation of Silane Coupling Agent on Bond Strength of Fiber Posts to Resin Cement. J Contemp Dent Pract 2019;20(11):1293-1296.

Efficiency of self-adhering flowable resin composite and different surface treatments in composite repair using a universal adhesive.

AIMS: The aim of this in vitro investigation was to evaluate the efficiency of self-adhering flowable resin composite (Vertise Flow, Kerr, Orange, CA, USA) and different surface treatments in the repair microtensile bond strength (µTBS) of aged nanofill resin composites using a universal adhesive. MATERIALS AND METHODS: Aged substrates (×5000 thermocycling) were prepared using a nanofill (Filtek Ultimate; 3M ESPE) resin composite and randomly assigned to different surface treatments: (1) no treatment (control), (2) acid etching with 37% phosphoric acid, (3) Al2O3sandblasting, and (4) sandblasting with CoJet (3M ESPE). After surface treatment, specimens were further divided into two groups: no universal adhesive application and universal adhesive application. Vertise Flow was added to the substrates at 2-mm layer increments to a height of 5 mm and light cured. Restored specimens were sectioned to obtain 1.0-mm2 beams for µTBS testing. Data were analyzed with two-way analysis of variance and Tukey's honest significant difference tests (P < 0.05). RESULTS: The lowest µTBS values were recorded in the control and acid etching groups with no universal adhesive application (P < 0.05). Universal adhesive application significantly increased the repair µTBS values of all surface treatments (P < 0.05), except CoJet treatment. There were no significant differences between Al2O3sandblasting, CoJet application, and acid etching groups with the universal adhesive application (P > 0.05). CONCLUSION: Vertise Flow can be used effectively in the repair of old nanofill resin composites. The usage of universal adhesive with prior acid etching to obtain acceptable repair performance would be the practical choice under clinical conditions.

[Effect of sandblasting on the microroughness of ceramic restorations]. / Vliianie aéroabrazivnoi obrabotki na mikrosherokhovatost' konstruktsii iz stomatologicheskoi polevoshpatnoi keramiki.

The influence of aero-abrasive technology on the microroughness of the ceramic samples standardized in shape, structure, and manufacturing method was studied by comparing the results obtained from the action of alumina particles of 27 and 50 µm size under a pressure of 0.5 and 2 atm for 5 seconds at a distance of 3 cm. To objectify the features of the treated surface relief its micro-roughness has been studied. With the help of a scanning electron microscope the morphology of studied samples was visualized. The data confirming the reliable absence of differences in the microroughness between the sandblasting methods under the given conditions was obtained. Microphotographs of samples surface obtained using the mode of reflected electrons detection showed no significant structural differences between all groups of samples. Thus, sandblasting can be integrated into the general algorithm as a stage of ceramics preparation for adhesive fixation since it does not cause mechanical damage to the surface, does not fundamentally change its structure and cleans the surface from contamination.

Influence of Ambient Air and Different Surface Treatments on the Bonding Performance of a CAD/CAM Composite Block.

PURPOSE: To evaluate the bond strengths of time elapsed after sandblasting with alumina particles on a CAD/CAM composite block treated with different surface conditioning methods. MATERIALS AND METHODS: A CAD/CAM composite block (CCB) was cut into 72 slices of approximately 2 mm thickness. The CCB slices were divided into three groups according to sandblasting pressure (0.1 MPa, 0.2 MPa, or untreated), and then divided into two subgroups according to the time elapsed after sandblasting: same-day or one-week dry storage under controlled laboratory conditions before cementation. Surface roughness was observed by confocal laser microscopy (CLSM) (n = 20); then the wettability of the CCB surfaces was examined using a contact angle (CA) measuring device on a droplet of deionized water (n = 12). Next, CCB slices were divided into three subgroups according to the surface treatment: Clearfil Ceramic Primer (CP), Clearfil Universal Bond (UB), or a mixture of Clearfil Porcelain Bond Activator and Clearfil tri-S Bond ND Quick (NDP). All CCB slices were then cemented with Panavia V5 and stored at 37°C in distilled water for 24 h and cut into sticks (n = 10). The sticks were subjected to microtensile bond strength (µTBS) testing, and failure mode analysis was performed using scanning electron microscopy. The µTBS results were subjected to 3-way and 2-way ANOVA (α = 0.05). RESULTS: All groups showed a statistically significant increase in wettability accompanied by decreased µTBS after one week; however, the UB group exhibited stable performance after one week. CONCLUSION: The time elapsed after sandblasting with alumina particles affects the bond strength, but it had no significant effect on the UB group.