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Masatoshi Nakajima - One of the best experts on this subject based on the ideXlab platform.
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Smear Layer-Deproteinization: Improving the Adhesion of Self-Etch Adhesive Systems to Caries-Affected Dentin
Current Oral Health Reports, 2018Co-Authors: Keiichi Hosaka, Taweesak Prasansuttiporn, Ornnicha Thanatvarakorn, Richard M Foxton, Junji Tagami, Sitthikorn Kunawarote, Masahiro Takahashi, Masatoshi NakajimaAbstract:Purpose of review This paper reviews a new method of dentin surface modification, Smear Layer-deproteinization for self-etch adhesive systems, particularly in relation to improving the adhesion to caries-affected dentin. Recent Findings Remnants of Smear debris, which forms hybridized Smear Layer with self-etch adhesives, can prevent monomer infiltration and interfere with the chemical interaction of adhesive monomers and the underlying dentin. The hybridized Smear Layer weakens the physical and chemical properties of the resin-dentin hybridized complex both immediately and over time. Smear Layer-deproteinization with NaOCl and HOCl solutions can improve the quality of resin-dentin interface of self-etch adhesives through elimination of the hybridized Smear Layer, development of monomer infiltration, and enhancement of the chemical interaction of adhesive monomers with hydroxyapatite due to an increase in the mineral/organic ratio on the dentin surface. These positive effects are influenced by the types of oxidizing solution and their application time and also depend upon the adhesive materials used because compromising effects of residual oxidized-byproducts at the dentin surface on the polymerization behavior of the adhesives are different between the materials. However, applying antioxidant/reducing agents can eliminate this problem. Summary Smear Layer-deproteinization is more effective for improving the bonding efficacy of self-etch adhesives to caries-affected dentin than normal dentin because caries-affected dentin produces a thicker organic-rich Smear Layer. Smear Layer-deproteinization with HOCl solution, which has a rapid and broad-spectrum antimicrobial activity with less irritating and sensitizing properties, along with the subsequent application of antioxidant/reducing agents could enhance the longevity of composite restoration with self-etch adhesives.
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Smear Layer deproteinization improving the adhesion of self etch adhesive systems to caries affected dentin
Current Oral Health Reports, 2018Co-Authors: Keiichi Hosaka, Taweesak Prasansuttiporn, Ornnicha Thanatvarakorn, Richard M Foxton, Junji Tagami, Sitthikorn Kunawarote, Masahiro Takahashi, Masatoshi NakajimaAbstract:This paper reviews a new method of dentin surface modification, Smear Layer-deproteinization for self-etch adhesive systems, particularly in relation to improving the adhesion to caries-affected dentin. Remnants of Smear debris, which forms hybridized Smear Layer with self-etch adhesives, can prevent monomer infiltration and interfere with the chemical interaction of adhesive monomers and the underlying dentin. The hybridized Smear Layer weakens the physical and chemical properties of the resin-dentin hybridized complex both immediately and over time. Smear Layer-deproteinization with NaOCl and HOCl solutions can improve the quality of resin-dentin interface of self-etch adhesives through elimination of the hybridized Smear Layer, development of monomer infiltration, and enhancement of the chemical interaction of adhesive monomers with hydroxyapatite due to an increase in the mineral/organic ratio on the dentin surface. These positive effects are influenced by the types of oxidizing solution and their application time and also depend upon the adhesive materials used because compromising effects of residual oxidized-byproducts at the dentin surface on the polymerization behavior of the adhesives are different between the materials. However, applying antioxidant/reducing agents can eliminate this problem. Smear Layer-deproteinization is more effective for improving the bonding efficacy of self-etch adhesives to caries-affected dentin than normal dentin because caries-affected dentin produces a thicker organic-rich Smear Layer. Smear Layer-deproteinization with HOCl solution, which has a rapid and broad-spectrum antimicrobial activity with less irritating and sensitizing properties, along with the subsequent application of antioxidant/reducing agents could enhance the longevity of composite restoration with self-etch adhesives.
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Smear Layer deproteinizing improves bonding of one step self etch adhesives to dentin
Dental Materials, 2017Co-Authors: Ornnicha Thanatvarakorn, Taweesak Prasansuttiporn, Shizuko Ichinose, Richard M Foxton, Junji Tagami, Suppason Thittaweerat, Keiichi Hosaka, Masatoshi NakajimaAbstract:Abstract Objectives Smear Layer deproteinizing was proved to reduce the organic phase of Smear Layer covered on dentin surface. It was shown to eliminate hybridized Smear Layer and nanoleakage expression in resin–dentin bonding interface of two-step self-etch adhesive. This study aimed to investigate those effects on various one-step self-etch adhesives. Methods Four different one-step self-etch adhesives were used in this study; SE One (SE), Scotchbond™ Universal (SU), BeautiBond Multi (BB), and Bond Force (BF). Flat human dentin surfaces with standardized Smear Layer were prepared. Smear Layer deproteinizing was carried out by the application of 50 ppm hypochlorous acid (HOCl) on dentin surface for 15 s followed by Accel® (p-toluenesulfinic acid salt) for 5 s prior to adhesive application. No surface pretreatment was used as control. Microtensile bond strength (μTBS) and nanoleakage under TEM observation were investigated. The data were analyzed by two-way ANOVA and Tukey’s post-hoc test and t-test at the significant level of 0.05. Results Smear Layer deproteinizing significantly improved μTBS of SE, SU, and BB (p Significance Smear Layer deproteinizing by HOCl and Accel® application could enhance the quality of dentin for bonding to one-step self-etch adhesives, resulting in the improving μTBS, eliminating hybridized Smear Layer and preventing reticular nanoleakage formation in resin–dentin bonding interface.
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effect of Smear Layer deproteinizing on resin dentine interface with self etch adhesive
Journal of Dentistry, 2014Co-Authors: Ornnicha Thanatvarakorn, Taweesak Prasansuttiporn, Shizuko Ichinose, Masatoshi Nakajima, Richard M Foxton, Junji TagamiAbstract:Abstract Objectives This study aimed to investigate deproteinizing effect of sodium-hypochlorite (NaOCl) and mild acidic hypochlorous-acid (HOCl) pretreatment on Smear Layer-covered dentine and to evaluate their effects on morphological characteristics of resin–dentine interface with self-etch adhesive. Methods Human coronal-dentine discs with standardized Smear Layer were pretreated with 6% NaOCl or 50 ppm HOCl for 15 s or 30 s. Their deproteinizing effects at the treated Smear Layer-covered dentine surfaces were determined by the measurement of amide:phosphate ratio using ATR-FTIR analysis. In addition, using TEM, micromorphological alterations of hybridized complex and nanoleakage expression were evaluated at the interface of a self-etch adhesive (Clearfil SE Bond) to the pretreated dentine surface with or without subsequent application of a reducing agent ( p -Toluenesulfinic acid salt; Accel ® ). Results Both pretreatments of NaOCl and HOCl significantly reduced the amide:phosphate ratio as compared with the no-pretreated group ( p Conclusions NaOCl and HOCl solutions could remove the organic component on the Smear Layer-covered dentine, which could eliminate the hybridized Smear Layer created by self-etch adhesive, leading to the reduction of nanoleakage expression within hybrid Layer. Clinical significance Smear Layer deproteinizing could modify dentine surface, giving an appropriate substrate for bonding to self-etch adhesive system.
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Effect of Smear Layer deproteinizing on resin–dentine interface with self-etch adhesive
Journal of Dentistry, 2013Co-Authors: Ornnicha Thanatvarakorn, Taweesak Prasansuttiporn, Shizuko Ichinose, Masatoshi Nakajima, Richard M Foxton, Junji TagamiAbstract:Abstract Objectives This study aimed to investigate deproteinizing effect of sodium-hypochlorite (NaOCl) and mild acidic hypochlorous-acid (HOCl) pretreatment on Smear Layer-covered dentine and to evaluate their effects on morphological characteristics of resin–dentine interface with self-etch adhesive. Methods Human coronal-dentine discs with standardized Smear Layer were pretreated with 6% NaOCl or 50 ppm HOCl for 15 s or 30 s. Their deproteinizing effects at the treated Smear Layer-covered dentine surfaces were determined by the measurement of amide:phosphate ratio using ATR-FTIR analysis. In addition, using TEM, micromorphological alterations of hybridized complex and nanoleakage expression were evaluated at the interface of a self-etch adhesive (Clearfil SE Bond) to the pretreated dentine surface with or without subsequent application of a reducing agent ( p -Toluenesulfinic acid salt; Accel ® ). Results Both pretreatments of NaOCl and HOCl significantly reduced the amide:phosphate ratio as compared with the no-pretreated group ( p Conclusions NaOCl and HOCl solutions could remove the organic component on the Smear Layer-covered dentine, which could eliminate the hybridized Smear Layer created by self-etch adhesive, leading to the reduction of nanoleakage expression within hybrid Layer. Clinical significance Smear Layer deproteinizing could modify dentine surface, giving an appropriate substrate for bonding to self-etch adhesive system.
Markus Haapasalo - One of the best experts on this subject based on the ideXlab platform.
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effect of Smear Layer against disinfection protocols on enterococcus faecalis infected dentin
Journal of Endodontics, 2013Co-Authors: Ya Shen, Zhejun Wang, Markus HaapasaloAbstract:Abstract Introduction This study examined the effect of the Smear Layer on the antibacterial effect of different disinfecting solutions in infected dentinal tubules. Methods Cells of Enterococcus faecalis were forced into dentinal tubules according to a previously established protocol. After a 3-week incubation period of infected dentin blocks, a uniform Smear Layer was produced. Forty infected dentin specimens were prepared and subjected to 3 and 10 minutes of exposure to disinfecting solutions including sterile water, 2% and 6% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 17% EDTA, and QMiX (Dentsply Tulsa Dental, Tulsa, OK). The following combinations were also included: 2% NaOCl + 2% CHX, 2% NaOCl + QMiX, 6% NaOCl + QMiX, and 6% NaOCl + 17% EDTA + 2% CHX. Four other dentin specimens similarly infected but with no Smear Layer were subjected to 3 minutes of exposure to 2% CHX and 6% NaOCl for comparison. Confocal laser scanning microscopy and viability staining were used to analyze the proportions of dead and live bacteria inside the dentin. Results In the presence of a Smear Layer, 10 minutes of exposure to QMiX, 2% NaOCl + QMiX, 6% NaOCl + QMiX, and 6% NaOCl + 17% EDTA + 2% CHX resulted in significantly more dead bacteria than 3 minutes of exposure to these same disinfecting solutions ( P P > .05); 6% NaOCl + QMiX and 6% NaOCl + 17% EDTA + 2% CHX showed the strongest antibacterial effect. In the absence of a Smear Layer, 2% CHX and 6% NaOCl killed significantly more bacteria than they did in the presence of a Smear Layer ( P Conclusions The Smear Layer reduces the effectiveness of disinfecting agents against E. faecalis in infected dentin. Solutions containing 6% NaOCl and/or QMiX showed the highest antibacterial activity.
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antibacterial and Smear Layer removal ability of a novel irrigant qmix
International Endodontic Journal, 2012Co-Authors: Sonja Stojicic, Ya Shen, Wei Qian, B Johnson, Markus HaapasaloAbstract:Stojicic S, Shen Y, Qian W, Johnson B, Haapasalo M. Antibacterial and Smear Layer removal ability of a novel irrigant, QMiX. International Endodontic Journal, 45, 363–371, 2012. Abstract Aim To assess in a laboratory experimental model the efficacy of a novel root canal irrigant, QMiX, against Enterococcus faecalis and mixed plaque bacteria in planktonic phase and biofilms. In addition, its ability to remove Smear Layer was examined. Methodology Enterococcus faecalis and mixed plaque bacteria were exposed to QMiX, 2% chlorhexidine (CHX), MTAD and 1% sodium hypochlorite (NaOCl) for 5 s, 30 s and 3 min. Following exposure, samples were taken, serially diluted and grown aerobically and anaerobically on tryptic soy agar (TSA) plates or on blood agar plates for 24 and 72 h, respectively, to measure killing of bacteria. E. faecalis and plaque biofilms were grown for 3 weeks on collagen-coated hydroxyapatite or dentine discs and exposed for 1 and 3 min to QMiX, 2% CHX, MTAD, 1% and 2% NaOCl. The amount of killed bacteria in biofilms was analysed by confocal laser scanning microscopy using viability staining. Dentine blocks were exposed to QMiX and 17% EDTA for 5 min. The effectiveness of Smear Layer removal by the solution was evaluated using scanning electron microscopy. For statistical analysis, one-way analysis of variance and comparison of two proportions were used. Results QMiX and 1% NaOCl killed all planktonic E. faecalis and plaque bacteria in 5 s, while 2% CHX and MTAD were unable to kill all plaque bacteria in 30 s, and some E. faecalis cells survived even 3 min of exposure. QMiX and 2% NaOCl killed up to 12 times more biofilm bacteria than 1% NaOCl (P < 0.01), 2% CHX (P < 0.05; P < 0.001) and MTAD (P < 0.05; P < 0.001). QMiX removed Smear Layer equally well as EDTA (P = 0.18 × 10−5). Conclusion QMiX and NaOCl were superior to CHX and MTAD under laboratory conditions in killing E. faecalis and plaque bacteria in planktonic and biofilm culture. Ability to remove Smear Layer by QMiX was comparable to EDTA.
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Irrigation: beyond the Smear Layer
Endodontic Topics, 2012Co-Authors: Markus Haapasalo, Wei Qian, Ya ShenAbstract:Traditionally, much of the attention placed on irrigation in endodontics has focused on Smear Layer removal. While the Smear Layer continues to be a relevant topic, other areas related to irrigation and irrigants have emerged that also require a more in-depth analysis and understanding. This review starts with the Smear Layer, partially from a new angle, and expands into other topics such as uninstrumented root canal areas, and effect of irrigation in lateral canals and dentin canals. Advanced microbiological models for irrigation research will be presented and discussed. The effect of sodium hypochlorite and decalcifying solutions on dentin structure and dentin strength has become an important topic, which is related to the possible harmful effects of irrigation such as dentin erosion and even vertical root fracture. The impact of irrigant sequence and time of exposure will also be discussed, and recommendations for irrigation protocols will be made
Jesus Djalma Pecora - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Smear Layer removal by edtac and sodium hypochlorite with ultrasonic agitation
International Endodontic Journal, 2002Co-Authors: Danilo Mathias Zanello Guerisoli, Melissa Andreia Marchesan, A D Walmsley, P J Lumley, Jesus Djalma PecoraAbstract:Aim To evaluate Smear Layer removal by different irrigating solutions under ultrasonic agitation. Methodology Twenty recently extracted mandibular incisors with a single root canal were divided into four equal groups. Three groups were instrumented using the modified double-flared technique, the fourth remained unprepared. Each group was irrigated with either distilled water, 1.0% sodium hypochlorite alone or associated with 15% EDTAC between each file size. The final group was not instrumented but irrigated with 1.0% sodium hypochlorite and 15% EDTAC. A size 15 file energised by ultrasound was used with small amplitude filing movements against the canal walls in all groups. The teeth were split longitudinally and the roots measured to provide three sections of the same size (cervical, middle and apical). Samples were examined under the scanning electron microscope and assessed for the amount of Smear Layer by three independent and calibrated examiners. The scoring system ranged from 1 (no Smear Layer) to 4 (all areas covered by Smear Layer). Due to the non-parametric nature of the data, Friedman’s test was used for statistical analysis. Results Canal walls were covered with Smear Layer in the group irrigated with 1% sodium hypochlorite alone and the group irrigated with distilled water. Canals irrigated with 1.0% sodium hypochlorite associated with 15% EDTAC had less Smear Layer throughout the canal (P < 0.001). There were no statistical differences for the amount of Smear Layer found on the cervical, middle and apical thirds when each group was analysed separately. Conclusions Under ultrasonic agitation, sodium hypochlorite associated with EDTAC removed the Smear Layer from root canal walls, whereas irrigation with distilled water or 1.0% sodium hypochlorite alone did not remove Smear Layer.
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Evaluation of Smear Layer removal by EDTAC and sodium hypochlorite with ultrasonic agitation
International endodontic journal, 2002Co-Authors: Danilo Mathias Zanello Guerisoli, Melissa Andreia Marchesan, A D Walmsley, P J Lumley, Jesus Djalma PecoraAbstract:Aim To evaluate Smear Layer removal by different irrigating solutions under ultrasonic agitation. Methodology Twenty recently extracted mandibular incisors with a single root canal were divided into four equal groups. Three groups were instrumented using the modified double-flared technique, the fourth remained unprepared. Each group was irrigated with either distilled water, 1.0% sodium hypochlorite alone or associated with 15% EDTAC between each file size. The final group was not instrumented but irrigated with 1.0% sodium hypochlorite and 15% EDTAC. A size 15 file energised by ultrasound was used with small amplitude filing movements against the canal walls in all groups. The teeth were split longitudinally and the roots measured to provide three sections of the same size (cervical, middle and apical). Samples were examined under the scanning electron microscope and assessed for the amount of Smear Layer by three independent and calibrated examiners. The scoring system ranged from 1 (no Smear Layer) to 4 (all areas covered by Smear Layer). Due to the non-parametric nature of the data, Friedman’s test was used for statistical analysis. Results Canal walls were covered with Smear Layer in the group irrigated with 1% sodium hypochlorite alone and the group irrigated with distilled water. Canals irrigated with 1.0% sodium hypochlorite associated with 15% EDTAC had less Smear Layer throughout the canal (P
Matthias Kern - One of the best experts on this subject based on the ideXlab platform.
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does endodontic post space irrigation affect Smear Layer removal and bonding effectiveness
European Journal of Oral Sciences, 2009Co-Authors: Caiyun Mao, Cong Liang, Huiming Wang, Matthias KernAbstract:The effect of different post space irrigants on Smear Layer removal and dentin bond strength was evaluated. Sixty-six extracted sound maxillary central incisors were endodontically treated. After post space preparation, the teeth were assigned to three groups of 22 teeth each. The teeth of these three groups were irrigated for 1 min with 17% ethylenediaminetetracetic acid (EDTA) (group 1), 5.25% sodium hypochlorite (NaOCl) (group 2), or 0.9% sodium chloride (NaCl) (group 3). In each group, eight specimens were split longitudinally for Smear Layer evaluation, and the other fourteen specimens were filled with a self-etching adhesive system (Panavia F). Four of 14 specimens of each group were prepared for evaluation of the resin-dentin interdiffusion zone (RDIZ) and resin tags, and the other 10 specimens were serially sectioned for push-out test analysis. Smear Layer removal and bond strength were affected by different post space irrigants. EDTA removed the Smear Layer extremely effectively and, as a result, improved the bond strength at each region (apical, middle, and coronal) of the roots. Resin tag formation and the RDIZ were also affected by different irrigants and in accordance with bond strength. Therefore, removal of the Smear Layer use a self-etching luting system plays an important role in bonding effectiveness.
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effect of different irrigation on Smear Layer removal after post space preparation
Journal of Endodontics, 2009Co-Authors: Caiyun Mao, Matthias KernAbstract:The purpose of this study was to evaluate the effect of different irrigating solutions on Smear Layer removal and dentinal tubule opening on root canal surfaces after post space preparation and to study whether additional ultrasonic irrigation has any effect on Smear Layer removal. Forty-eight anterior teeth were treated endodontically. After post space preparation, they were assigned to six groups: group 1, EDTA; group 2, EDTA with ultrasonic activation; group 3, sodium hypochlorite (NaOCl); group 4, NaOCl with ultrasonic activation; group 5, sodium chloride (NaCl); and group 6, NaCl with ultrasonic activation. Specimens were examined under a field-emission scanning electron microscope and scored for debris removal and dentinal tubule opening at the coronal, middle, and apical thirds of the root canal. The results showed that EDTA performed significantly better than NaCl and NaOCl in Smear Layer removal and dentinal tubule opening. Additional ultrasonic irrigation did not improve Smear Layer removal significantly.
Ya Shen - One of the best experts on this subject based on the ideXlab platform.
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effect of Smear Layer against disinfection protocols on enterococcus faecalis infected dentin
Journal of Endodontics, 2013Co-Authors: Ya Shen, Zhejun Wang, Markus HaapasaloAbstract:Abstract Introduction This study examined the effect of the Smear Layer on the antibacterial effect of different disinfecting solutions in infected dentinal tubules. Methods Cells of Enterococcus faecalis were forced into dentinal tubules according to a previously established protocol. After a 3-week incubation period of infected dentin blocks, a uniform Smear Layer was produced. Forty infected dentin specimens were prepared and subjected to 3 and 10 minutes of exposure to disinfecting solutions including sterile water, 2% and 6% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 17% EDTA, and QMiX (Dentsply Tulsa Dental, Tulsa, OK). The following combinations were also included: 2% NaOCl + 2% CHX, 2% NaOCl + QMiX, 6% NaOCl + QMiX, and 6% NaOCl + 17% EDTA + 2% CHX. Four other dentin specimens similarly infected but with no Smear Layer were subjected to 3 minutes of exposure to 2% CHX and 6% NaOCl for comparison. Confocal laser scanning microscopy and viability staining were used to analyze the proportions of dead and live bacteria inside the dentin. Results In the presence of a Smear Layer, 10 minutes of exposure to QMiX, 2% NaOCl + QMiX, 6% NaOCl + QMiX, and 6% NaOCl + 17% EDTA + 2% CHX resulted in significantly more dead bacteria than 3 minutes of exposure to these same disinfecting solutions ( P P > .05); 6% NaOCl + QMiX and 6% NaOCl + 17% EDTA + 2% CHX showed the strongest antibacterial effect. In the absence of a Smear Layer, 2% CHX and 6% NaOCl killed significantly more bacteria than they did in the presence of a Smear Layer ( P Conclusions The Smear Layer reduces the effectiveness of disinfecting agents against E. faecalis in infected dentin. Solutions containing 6% NaOCl and/or QMiX showed the highest antibacterial activity.
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antibacterial and Smear Layer removal ability of a novel irrigant qmix
International Endodontic Journal, 2012Co-Authors: Sonja Stojicic, Ya Shen, Wei Qian, B Johnson, Markus HaapasaloAbstract:Stojicic S, Shen Y, Qian W, Johnson B, Haapasalo M. Antibacterial and Smear Layer removal ability of a novel irrigant, QMiX. International Endodontic Journal, 45, 363–371, 2012. Abstract Aim To assess in a laboratory experimental model the efficacy of a novel root canal irrigant, QMiX, against Enterococcus faecalis and mixed plaque bacteria in planktonic phase and biofilms. In addition, its ability to remove Smear Layer was examined. Methodology Enterococcus faecalis and mixed plaque bacteria were exposed to QMiX, 2% chlorhexidine (CHX), MTAD and 1% sodium hypochlorite (NaOCl) for 5 s, 30 s and 3 min. Following exposure, samples were taken, serially diluted and grown aerobically and anaerobically on tryptic soy agar (TSA) plates or on blood agar plates for 24 and 72 h, respectively, to measure killing of bacteria. E. faecalis and plaque biofilms were grown for 3 weeks on collagen-coated hydroxyapatite or dentine discs and exposed for 1 and 3 min to QMiX, 2% CHX, MTAD, 1% and 2% NaOCl. The amount of killed bacteria in biofilms was analysed by confocal laser scanning microscopy using viability staining. Dentine blocks were exposed to QMiX and 17% EDTA for 5 min. The effectiveness of Smear Layer removal by the solution was evaluated using scanning electron microscopy. For statistical analysis, one-way analysis of variance and comparison of two proportions were used. Results QMiX and 1% NaOCl killed all planktonic E. faecalis and plaque bacteria in 5 s, while 2% CHX and MTAD were unable to kill all plaque bacteria in 30 s, and some E. faecalis cells survived even 3 min of exposure. QMiX and 2% NaOCl killed up to 12 times more biofilm bacteria than 1% NaOCl (P < 0.01), 2% CHX (P < 0.05; P < 0.001) and MTAD (P < 0.05; P < 0.001). QMiX removed Smear Layer equally well as EDTA (P = 0.18 × 10−5). Conclusion QMiX and NaOCl were superior to CHX and MTAD under laboratory conditions in killing E. faecalis and plaque bacteria in planktonic and biofilm culture. Ability to remove Smear Layer by QMiX was comparable to EDTA.
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Irrigation: beyond the Smear Layer
Endodontic Topics, 2012Co-Authors: Markus Haapasalo, Wei Qian, Ya ShenAbstract:Traditionally, much of the attention placed on irrigation in endodontics has focused on Smear Layer removal. While the Smear Layer continues to be a relevant topic, other areas related to irrigation and irrigants have emerged that also require a more in-depth analysis and understanding. This review starts with the Smear Layer, partially from a new angle, and expands into other topics such as uninstrumented root canal areas, and effect of irrigation in lateral canals and dentin canals. Advanced microbiological models for irrigation research will be presented and discussed. The effect of sodium hypochlorite and decalcifying solutions on dentin structure and dentin strength has become an important topic, which is related to the possible harmful effects of irrigation such as dentin erosion and even vertical root fracture. The impact of irrigant sequence and time of exposure will also be discussed, and recommendations for irrigation protocols will be made