Adhesive Type Research Articles

Creep behaviour of adhesively bonded joints: A comprehensive review

This review paper provides an exploration of various facets of creep behaviour in adhesives and adhesive joints, encompassing experimental procedures, prediction models, influential parameters and strategies to enhance resistance. The discussion extends to the interplay between fatigue and creep, emphasising recent advances over the last two decades. While avoiding redundancy with prior work on temperature and moisture degradation, the paper articulates connections between topics for a better understanding. A critical examination of load levels reveals that small variations significantly impact the creep life of adhesive joints, particularly prominent with epoxy adhesives. The adhesive type, joint geometry and substrate material are scrutinised, revealing distinct impacts on creep behaviour. The study underscores the critical role of adhesive thickness and overlap length, emphasising their relevance in determining the time to failure in bonded joints under creep conditions. Notably, the substrate material’s role is highlighted. As the review delves into unexplored dimensions, it calls for further research to bridge existing gaps and refine our understanding of tertiary creep and time until failure.

The use of wood veneer to beautify wood plastic composites

Wood-plastic composites (WPC) can be regarded as environmentally-friendly materials which are mainly manufactured with recycled wood and thermoplastics. However, it is difficult to decorate WPCs with wood veneer using the types of polar adhesives which are commonly used in the woodworking industry due to the nonpolar and nonporous surfaces of WPCs. In the present study, four kinds of abrasive material, including sanding paper, industrial scouring pad, nylon and steel wire wheels were evaluated as a means of promoting adhesion between a wood fiber/high-density polyethylene (WF/HDPE) board and wood veneer using an isocyanate-crosslinking polyvinyl acetate adhesive. Based on the test results of bonding strength and water resistance, it was found that neither the sanding paper commonly used in the woodworking industry, nor steel wire commonly used in the WPC industry were particularly effective, with the scouring pad approach (nylon substrate entangled with silicon carbide) being the best choice. Scanning electron microscopy, Fourier-transform infrared spectroscopy, contact angle measurements, and roughness tests were used to analyze the surface properties of abraded surfaces. Although all four abrasion materials scraped the surface plastic layer off and exposed the wood fibers, they formed significantly different morphologies and affected surface wettability. A combination of suitable surface roughness and enough fiber exposure was found to be necessary for a WF/HDPE composite to build a good glue line. Abrasion with an industrial scouring pad might be a simple and effective method for removing a surface layer and aiding the application of a decorative layer.

Experimental investigation of the mode I fracture toughness behaviour of timber adhesive joints: The synergistic effect of the adhesive type and the bondline thickness

Timber is a construction material widely used for structural applications. In the last decades, the improvements of both the bonding techniques and the quality of the adhesives enabled to overcome the intrinsic limitations of sawn timber, resulting in a wide spread of engineered wood products (EWPs). Understanding and assessing the bonding quality of structural EWPs has become nowadays a crucial point to assure their load-bearing capacity and even to increase their performance. One of the most revealing properties to assess the bonding quality and behavior is the fracture energy (or toughness), which could be estimated by performing suitable tests. In the present work, the results of an experimental campaign aimed to define the mode I fracture toughness of timber-to-timber adhesive bonding are presented and discussed. The fracture toughness behavior of three different categories of adhesives for structural applications was investigated, namely melamine-urea-formaldehyde (MUF), polyurethane (PU) and phenol-resorcinol-formaldehyde (PRF). In addition, the effect of the adhesive bondline and precrack thickness (0.15 and 0.30 mm) was also investigated. The results revealed different fracture toughness behaviour between the various adhesives and bond line thickness, in terms of both crack initiation and propagation. In fact, the mode-I fracture toughness appears to be highly dependent on the adhesive type, as also seen by the related analysis of variance. The fractured surfaces are also characterized by means of optical microscopy, giving insights about the local failure modes.

Hygrothermal ageing of dry gelatine adhesive films: Microstructure-property relationships

Gelatine adhesives, also known as animal glues, are collagen-based water-soluble biopolymers derived from vertebrate connective tissues. One of the various fields in which gelatine adhesives are widely used is the conservation of cultural heritage such as decorated furniture and panel paintings. It is observed that, with time, the failure in these objects often occurs along the adhesive bondlines. Given the moisture and temperature sensitivity of these adhesives, obtaining knowledge of their long-term behaviour, when exposed to climate variations, is pivotal. Here, the influence of hygrothermal ageing (exposure to a combination of elevated temperature and relative humidity (RH) cycling) on the microstructure and macroscopic properties of four different types of gelatine adhesives is investigated. These adhesives were selected from different animal origins namely bovine, rabbit, and fish with different Bloom strengths. It was observed that ageing cycles interfere with the most critical structural feature of protein chains namely triple helices. A clear decay in triple helix content at the micro-scale, determined by Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) techniques, was observed which had implications on the macroscopic properties of these adhesives such as reduction of strain to failure and toughness (strain energy density to failure). The rate of decay in properties was revealed to be the highest in the adhesives with the lowest triple helix content. This study provides a scientific view of microstructure-property relationships in gelatinous adhesives as a function of environmental ageing, and stipulates the underlying mechanism of the degradation of mechanical properties as the loss of structural triple helices, regardless of the animal origin.

Adhesion of Historic Tile Fragments in Outdoor Architectural Settings

Azulejos are part of Portugal’s most important cultural heritage. However, a large part of this heritage is at risk due to lack of or improper conservation treatments. There are, however, not many studies dedicated to the procedures and materials used in their conservation to guide the choices of conservators/restorers. Through this work, the performances of the adhesives commonly used in azulejo conservation are studied considering the extreme conditions they may experience when in an outdoor environment. Three types of adhesives were studied: acrylics, epoxies, and cellulose nitrates. The adhesives were evaluated for their workability and characterized by FTIR, DMA, and bending tests to obtain information on their adhesion effectiveness and compatibility with the azulejo ceramic substrate before and after artificial and natural ageing. When subjected to mechanical loads, the high strength and stiffness of the epoxy resins could lead to the development of new fractures in the previously undamaged ceramic matrix, making them less suitable for the adhesion of historic tile fragments. Cellulose nitrates revealed a high chemical alteration and the highest degradation rate in the mechanical properties with ageing, showing it to be the least stable in the studied conditions. The acrylic resins proved to be the most chemically stable, with less yellowing and with physical properties that revealed to be the most compatible for the adhesion of the studied azulejo fragments in outdoor environments.

Synergistic effect of surface treatment and adhesive type on bonding performance of thin Al6061 joints for automotive applications

The effects of different surface treatments (grinding, plasma surface treatment, and grinding followed by the plasma (GrPl) process) and various adhesives (cyanoacrylate, Bisphenol A (BPA)-based, and Bisphenol A and Bisphenol F (BPA/F)-based adhesive) on the bonding performance of single-lap joints manufactured from thin Al6061-T4 aluminium alloy sheets were investigated in this study. Contact angle measurement was carried out to evaluate the influence of surface treatments on the wettability of the surface of the aluminium alloy adherends. The contact angle on the surface of the untreated sheet was measured to be 71.8°. However, after applying the GrPl process on the ground surface, the contact angle could be reduced to 47° and 25.9° in the parallel and perpendicular directions to the grinding direction, respectively. Shear testing was performed to evaluate the mechanical behaviour of the single-lap joints of aluminium alloy sheets. The shear strengths of BPA/F-based, cyanoacrylate, and BPA-based adhesive-bonded joints produced from ground adherends improved by 47 %, 54 %, and 72 %, respectively. The synergistic impact of GrPl treatment resulted in 126 %, 123 %, and 174 % enhancement in shear strength of BPA/F-based, cyanoacrylate, and BPA-based adhesive-bonded joints, respectively. When the temperature was raised from room temperature to 60 °C, the bonding performances of all single-lap joints deteriorated due to the decrease in the strength of the adhesive. However, the joints treated with plasma had the highest shear strength at 60 °C. While the BPA-based adhesive had the most beneficial impact on improving the shear strength of single-lap joints at room temperature, the opposite result was obtained at 60 °C. All the findings have indicated that the influence of adhesive on the bonding performance of aluminium alloy joints varied significantly depending on the surface treatment and temperature.

A mussel inspired polyvinyl alcohol/collagen/tannic acid bioadhesive for wet adhesion and hemostasis

Bioadhesives are useful in surgery for hemostasis, tissue sealing and wound healing. However, most bioadhesives have limitations such as weak adhesion in wet conditions, insufficient sealing and poor clotting performance. Inspired by the adhesion mechanism of marine mussels, a novel bioadhesive (PCT) was developed by simply combining polyvinyl alcohol (PVA), collagen (COL) and tannic acid (TA) together. The results showed that the adhesion, sealing and blood coagulation properties boosted with the increase of tannic acid content in PCT. The wet shear adhesion strength of PCT-5 (the weight ratio of PVA:COL:TA=1:1:5) was 60.8 ± 0.6 kPa, the burst pressure was 213.7 ± 0.7 mmHg, and the blood clotting index was 39.3% ± 0.6%, respectively. In rat heart hemostasis tests, PCT-5 stopped bleeding in 23.7 ± 3.2 s and reduced bleeding loss to 83.0 ± 19.1 mg, which outperformed the benchmarks of commercial gauze (53.3 ± 8.7 s and 483.0 ± 15.0 mg) and 3 M adhesive (Type No.1469SB, 35.3 ± 5.0 s and 264.0 ± 14.2 mg). The as-prepared bioadhesive could provide significant benefits for tissue sealing and hemorrhage control along its low cost and facile preparation process.

Mechanical behavior investigation of fused deposition modeling joints by using different bonding geometry with variable adhesive thickness

PurposeAdhesively bonded joints are used in many fields, especially in the automotive, marine, aviation, defense and outdoor industries. Adhesive bonding offers advantages over traditional mechanical methods, including the ability to join diverse materials, even load distribution and efficient thermal-electrical insulation. This study aims to investigate the mechanical properties of adhesively bonded joints, focusing on adherends produced with auxetic and flat surfaces adhered with varying adhesive thicknesses.Design/methodology/approachThe research uses three-dimensional (3D)-printed materials, polyethylene terephthalate glycol and polylactic acid, and two adhesive types with ductile and brittle properties for single lap joints, analyzing their mechanical performance through tensile testing. The adhesion region of one of these adherends was formed with a flat surface and the other with an auxetic surface. Adhesively bonded joints were produced with 0.2, 0.3 and 0.4 mm bonding thickness.FindingsResults reveal that auxetic adherends exhibit higher strength compared to flat surfaces. Interestingly, the strength of ductile adhesives in auxetic bonded joints increases with adhesive thickness, while brittle adhesive strength decreases with thicker auxetic bonds. Moreover, the auxetic structure displays reduced elongation under comparable force.Originality/valueThe findings emphasize the intricate interplay between adhesive type, bonded surface configuration of adherend and bonding thickness, crucial for understanding the mechanical behavior of adhesively bonded joints in the context of 3D-printed materials.

Adhesive Cementation of CAD/CAM Silica-based Ceramics: Effect of Adhesive Type and Long-term Aging on the Bond Strength to Composite Cement.

To investigate the effect of adhesive type and long-term aging on the shear bond strength (SBS) between silica-based ceramics and composite cement (CC). Lithium-silicate (LS), feldspathic (FD) and polymer-infiltrated ceramic (PIC) blocks were sectioned (10 x 12 x 2 mm) and divided into 24 groups considering the factors: "ceramics" (LS, FD, and PIC), "adhesive" (Ctrl: without adhesive; 2SC: 2-step conventional; 3SC: 3-step conventional; 1SU: 1-step universal), and "aging" (non-aged or aged [A]). After the surface treatments, CC cylinders (n = 15, Ø = 2 mm; height = 2 mm) were made and half of the samples were subjected to thermocycling (10,000) and stored in water at 37°C for 18 months. The samples were submitted to SBS testing (100 kgf, 1 mm/min) and failure analysis. Extra samples were prepared for microscopic analysis of the adhesive interface. SBS (MPa) data was analyzed by 3-way ANOVA and Tukey's test (5%). Weibull analysis was performed on the SBS data. All factors and interactions were significant for SBS (p<0.05). Before aging, there was no significant difference between the tested groups and the respective control groups. After aging, the LS_1SU (22.18 ± 7.74) and LS_2SC (17.32 ± 5.86) groups exhibited significantly lower SBS than did the LS_Ctrl (30.30 ± 6.11). Only the LS_1SU group showed a significant decrease in SBS after aging vs without aging. The LS_1SU (12.20) group showed the highest Weibull modulus, which was significantly higher than LS_2SC_A (2.82) and LS_1SU_A (3.15) groups. No type of adhesive applied after silane benefitted the long-term adhesion of silica-based ceramics to CC in comparison to the groups without adhesive.

Glulam beams adhesively bonded by birch plywood plates in moment-resisting beam-to-beam connections

The design of timber connections is of vital importance in timber structures. Bonded connections exhibit the advantages of lower cost, higher load-bearing capacity, and higher stiffness compared to conventional mechanical connections. However, the potential of the bonded connections has yet to be fully exploited, not only due to their sensitivity to the adhesive types and process-related parameters but also due to the lack of studies regarding the structural performance of the bonded connection in various loading conditions. In this paper, birch plywood plates were utilized to adhesively connect two glulam beam halves to create a longer span. Plywood made of birch was chosen because birch is highly resourced on the Eurasian continent, with its mechanical properties better than most softwoods. Specifically, glulam beams were connected by birch plywood plates at mid-span and then loaded in four-point bending. Four test series with two different bonding areas and birch plywood face grain orientations were carried out. The bonded region was designed as the weakest part to investigate the failure modes, moment capacity, bending stiffness, and moment-rotation angle relationships. Furthermore, numerical models were developed to predict the structural behaviors in the linear elastic stage, while analytical models were proposed and subsequently modified to predict the moment-carrying capacities. Both numerical and analytical models displayed satisfactory agreement with the test results.

Effect of Pyrolysis Temperature and Adhesive Type on the Quality of Biobriquette from Coffee Stem Biomass

Biobriquette is organic waste charcoal printed in such a way that has a high energy density and calorific value. The biobriquette quality is influenced by several factors, including the pyrolysis temperature and the adhesive type. This research aims to evaluate the effect of pyrolysis temperature (250°C, 300°C, and 350°C) and adhesive type (tapioca, molasses, and a tapioca-molasses mixture) on the quality of biobriquette from coffee stem. This research steps include pyrolysis of coffee stem, biobriquette production, and quality analysis of biobriquette. The biobriquette quality described refers to SNI No. 01-6235-2000, including water content, ash content, volatile matter, calorific value, and additional analysis, including fixed carbon, density, compressive strength, and combustion rate. This research shows that increasing the pyrolysis temperature will increase the charcoal yield. Pyrolysis temperature and adhesive type affect the quality of biobriquette. All biobriquette produced at a pyrolysis temperature of 350°C met SNI No. 01-6235-2000, in terms of water, ash, volatile, and heating values. The best biobriquette was obtained with a pyrolysis temperature of 350°C and tapioca adhesive, with water content of 2.45%, ash content of 2.35%, volatile matter of 1.24%, density of 1,345 g/cm3, compressive strength of 91.775 kg/cm2, and a calorific value of 7,463.957 cal/g.

The possibility of application of bonded joints on different facade systems

Bonded joints in the construction industry have a rich history dating back to ancient civilisations, where they were mainly used to join materials such as wood or stone. In particular, natural materials such as bitumen or natural resins were used for this purpose. In the present modern era, with the development of adhesive technologies and synthetic adhesives, they have become an essential part of construction industry practice. Within facade cladding, bonded joints are becoming key to achieving high thermal insulation performance and overall building energy efficiency. The correct design of the building envelope is increasingly relevant in the context of the geopolitical situation starting with the global pandemic COVID-19 and the two conflicts between Russia and Ukraine and between Israel and Palestine that resulted in energy crises [1]. The paper summarizes the potential applications of adhesive bonded joints on facades, the types of adhesives used at different joints and their ability to provide strong and durable joints when exposed to different climatic conditions during summer and winter months.

Experimental Study of Physical Properties of Laminated Veneer Lumber Made by Three Cameroonian Hardwoods with Two Adhesives

This work deals with the determination of some properties of laminated veneer lumber (LVL) made from tropical hardwoods, specifically focusing on Cameroonian woods. The LVL samples are manufactured using veneer from three tropical wood species: Ayous, Ilomba, and Bete. Two types of adhesives are used: a neoprene contact adhesive (Magpow) and a white vinyl adhesive (Nemo). The specimens have undergone multiple drying cycles, and hundreds of samples from each species have been selected with dimensions of 1 cm × 1 cm × 1 cm. These samples are then machined according to the specific wood grain of each species. The experiments conducted aim to determine properties such as moisture content, densities, volume swelling, shrinkage coefficients, and the hygroscopic point of equilibrium of the samples. Swelling and shrinkage measurements allow for the visualization of sample dimensions in relation to humidity levels, and the hysteresis of the adsorption phenomenon of the LVL is also obtained. The results show that regardless of the type of adhesive or veneer used, LVLs are denser than the wood they are made from. For each type of LVL, the ratio between the mass of a sample saturated in water and the mass of the dried sample remains constant. The rule of mixture is investigated, and the density properties of materials and the vacuum rates of LVL samples are compared with experimental data.

Influence of Application Modes on Increasing Bond Strength Longevity of Self-etching and Universal Adhesive Systems to Enamel.

The present study aimed to evaluate the influence of application mode on the short-term microshear bond strength longevity of self-etching and universal adhesive systems to enamel, the failure mode, and the resulting enamel surface micromorphology. Ninety enamel surfaces were obtained from sound third molars, planed, and randomly assigned to nine groups, according to the application mode and the adhesive system (n=10). There were three primer application modes: according to the manufacturer's recommended application time (control), using double the application time recommended for the primer and selective enamel etching. The adhesive systems used were: Clearfil SE Bond (Kuraray), FL-Bond II (SHOFU), and Futurabond U (Voco). At least two resin-bonded composite cylinders (Grandioso Light Flow, Voco) were placed on each enamel surface, and then evaluated for microshear bond strength at 24 hours and 180 days of storage in solution body fluid (SBF) at pH 7.4. Failure modes were evaluated with a stereoscopic microscope at 20× magnification. A micromorphological analysis of the enamel surface was performed under a scanning electron microscope at 5000× magnification before and after the treatments. Mixed models for repeated measures over time showed significant interaction among application modes, adhesive systems, and time periods (p=0.0331). The bond strength of FL-Bond II adhesive to enamel observed after performing selective enamel etching was significantly higher than that observed after applying the control treatment (p=0.0010) at both 24 hours and 180 days. However, no significant difference was observed between the application of this same adhesive at double the time recommended by the manufacturer and the other two application modes (p>0.05). There was also no significant difference in the microshear bond strength for the enamel treatments applied using Clearfil SE Bond and Futurabond U (p>0.05). A significant reduction in bond strength to enamel was observed at the 180-day storage time for all the adhesive systems when selective enamel etching was performed (p<0.0001). No significant association was observed between the adhesive system failure mode and the enamel treatments (p=0.1402 and p=0.7590 for 24 hours and 180 days, respectively). The most prevalent failure was the adhesive type.

Study of different initiation and propagation criteria in the XFEM modelling of scarf adhesive joints

Scarf adhesive joints, characterized by an end-to-end connection between tapered adherents at a given scarf angle (α), are applicable in structural applications, e.g., fiber-reinforced structures, owing to their efficiency. This work presents an analysis on the tensile strength of scarf adhesive joints, considering a and the adhesive type as design parameters. A detailed numerical evaluation is presented, based on the eXtended Finite Element Method (XFEM), following the technique validation with experimental data, for adhesives with different characteristics. The XFEM technique was tested with varying damage initiation and propagation criteria. The XFEM technique was positively validated for specific damage initiation and propagation criteria.

Peripheral Neuropathy Resembling CIDP Following Exposure to Toxic Fumes in Shoe Factory: A Case Report

Abstract Different types of solvents and adhesives are used in a shoe factory. The toxic chemicals can cause acute and chronic effects on the central and peripheral nervous system. Here, we report a case of a 25-year-old young man working as a coloring and gluing worker in a shoe factory, who presented with progressive quadriparesis following exposure of six months. Some of his coworkers also developed a similar illness. Nerve conduction velocity studies of the patient showed combined sensory and motor demyelinating and axonal polyneuropathy. Cerebrospinal fluid (CSF) analysis was normal. With conservative management and physiotherapy, there is a gradual improvement of the condition in the patient who can ambulate independently now.

Evaluation of Type III Adhesive Mortar (ACIII) and Gypsum as Precipitating Agents of Copper and Lead

Heavy metals exhibit characteristics such as nonbiodegradable nature, toxic character, bioaccumulation capability, and ability to transit over long distances. The widespread application of these metal ions in various industrial sectors has led to an increase in their release into the environment. Chemical precipitation has been one of the technologies used to remove heavy metals from wastewater, involving a process in which chemical agents are added to wastewater with dissolved toxic metal ions, which react with the metals, forming insoluble precipitates. Therefore, the present study aimed to assess the potential of gypsum and adhesive mortar type III (ACIII) as precipitating agents for lead (Pb) and copper (Cu) ions, as well as to evaluate the toxicity of precipitation products on Drosophila melanogaster. Experiments using ACIII mortar waste as a precipitating agent for Cu ions were obtained using a glass filter composed of 04 chambers and 04 antechambers, while the potential of gypsum as a Pb ion precipitant was evaluated by adding gypsum powder to a beaker containing a Pb ions solution. The toxicity of the precipitation products was evaluated by observing the mortality and negative geotaxis parameters on D. melanogaster. In the tests using ACIII mortar as a precipitating agent for Cu, retention percentages progressively varied, obtaining 98.82% at a concentration of 30 mg/L. Meanwhile, gypsum obtained retention percentages that varied from 32.83 to 98.61% for Pb. It was found that the precipitates of Cu and Pb resulted in alterations in the survival and locomotion rates of D. melanogaster only at the highest evaluated concentrations. In conclusion, the results obtained indicated that geomaterials such as ACIII mortar and gypsum have potential for the removal of Cu and Pb from aqueous solutions. Moreover, the precipitation stages by these materials also impact in decreasing the toxicity of metal ions to the evaluated model organism.

Analyzing the effects of multiple adhesives on elastic collisions and energy loss in a Newton’s Cradle

The energy conservation in a system of objects in collision depends on the elasticity of the objects and environmental factors such as air resistance. One system that relies heavily on elasticity is the Newton’s Cradle. The elasticity of the spheres is what allows prolonged movement, but these spheres also excessively collide, causing more energy to be lost. Were an adhesive to be added to these spheres, then the elasticity would decrease, and so too would the chaotic movements that cause loss of energy. We aimed to determine the extent to which these adhesives serve to mitigate or worsen the chaotic movements and elastic collisions. Knowing the extent to which adhesives may mitigate radical interactions could allow for the building of more efficient procedures reliant upon elastic collisions, such as an elastic and inelastic collision apparatuses. We hypothesized that for all tested types/levels of adhesives, the final sphere would travel a shorter distance than the control. We also hypothesized that the rate at which the distance traveled decreased would increase as more adhesives were added. Although the maximum distance reached for all trials with adhesives was less than the control, each adhesive type varied in its effect on how the maximum distance reached changed. Results also varied pertaining to the correlation between the layers of adhesives and decreased rate of swings. Our findings display complex effects of multiple adhesives on elasticity and confounding movements within a system that relies heavily upon these characteristics to perpetuate motion in the system.

Effect of at-home and in-office bleaching on microleakage of class V composite resin restorations using different types of universal adhesives: An in vitro study.

When bleaching agents contact dental structures, they act on restorative materials and adhesive interfaces. This study investigated the effect of "at-home" and "in-office" bleaching on the microleakage of composite resin restorations performed with different universal adhesives in self-etch and etch-and-rinse modes. Class V cavities were prepared in 132 premolars. The samples were divided into four groups (n=33). All Bond Universal adhesive was used in the first and second groups, and G-Premio Bond adhesive was used in the third and fourth groups. The total-etch mode was used in the first and third groups, and the self-etch mode was used in the second and fourth groups. The samples were divided into three subgroups (n=11). In the first subgroup, home bleaching was used, and in the second subgroup, office bleaching was used. In the third subgroup, bleaching was not performed. The specimens were examined under a stereomicroscope for microleakage. Ordinal regression analysis was applied (P<0.05). The adhesive type, application method, and margin type significantly affected microleakage (P<0.05). The amount of microleakage in All Bond Universal adhesive was significantly higher than in G-Premio Bond adhesive. The chance of microleakage in the self-etch mode was almost twice as high as in the etch-and-rinse mode. The bleaching method did not significantly affect microleakage (P>0.05). Based on the results of the microleakage test, bleaching after composite resin restorations did not significantly affect the microleakage of Class V restorations.

Effect of Different Protocols on The Microleakage of A Fissure Sealant Applied During Saliva Contamination

Statement of the problem: Saliva contamination during sealant application has negative consequences that affects long-term success including retention and caries progression. Objective: The effect of different protocols to minimize the effect of saliva contamination on the microleakage of a resin based fissure sealant material (3M Clinpro™ Sealant) was investigated. Materials &amp; Methods: Extracted human third molars (n=160) were used: Group A. Etch-and-rinse adhesive (Prime &amp; Bond One Select); Group B. Selfetching adhesive (Clearfil SE Bond). These comprised eight paired subgroups where enameloplasty was done (or not), saliva contamination occurred before (or after) the polymerization of the bonding agent and the entire procedure was repeated (or not) following saliva contamination before the sealant application. Following thermocycling, the samples were immersed in basic fuchsin, sectioned, and dye penetration was quantitatively assessed with ImageJ. The data were statistically analyzed (α=0.05). Results: Significantly less microleakage was observed in Group A (P=0.000). Intergroup differences with respect to the effect of adhesive type, enameloplasty, saliva contamination occurred after the polymerization of the bonding agent and repeating the entire procedure following saliva contamination were significant (p&lt;0.05, each). Enameloplasty reduced microleakage in subgroups of A and B (P=0.002 and P=0.014, respectively). Saliva contamination after the polymerization of the bonding agent resulted in less microleakage in subgroups of A and B (P=0.01 and P=0.002, respectively). Less microleakage was observed in subgroups of A and B where the entire procedure was repeated following saliva contamination (P=0.000, both). Conclusions: The use of etch-and-rinse adhesive, enameloplasty, saliva contamination occurring after the polymerization of the bonding agent and repeating the entire procedure reduced microleakage of the fissure sealant applied during saliva contamination.