San-Jun Zhao

Fourth Military Medical University, Xi’an, Liaoning, China

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Publications (13)14.42 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To identify proteoglycans (PGs) and collagen fibrils (CF) within human dentin by means of a dual immunofluorescent labeling technique and to investigate the monomer infiltration of two etch-and-rinse adhesives to tosyl-phenylalanine chloromethyl-ketone (TPCK)-treated trypsin (TRY)-pretreated dentin.
    Dental materials: official publication of the Academy of Dental Materials 06/2014; · 2.88 Impact Factor
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    ABSTRACT: Objectives To identify proteoglycans (PGs) and collagen fibrils (CF) within human dentin by means of a dual immunofluorescent labeling technique and to investigate the monomer infiltration of two etch-and-rinse adhesives to tosyl-phenylalanine chloromethyl-ketone (TPCK)-treated trypsin (TRY)-pretreated dentin. Methods Thirty-micrometer sections of middle coronal dentin were obtained and etched with 37% phosphoric acid gel for 15 s. After preconditioning with or without TRY digestion, the sections were subjected to dual immunofluorescent labeling and observed with a confocal laser scanning microscope (CLSM). Demineralized dentin matrixes treated with or without TRY were observed with field emission scanning electron microscope (FE-SEM). Two etch-and-rinse adhesives, Adper Single Bond 2 (SB) and Prime & Bond NT (PBNT), were applied to the dentin surfaces that were pretreated with or without TRY. The thickness of the hybrid layers was evaluated under confocal micro-Raman spectroscopy and analyzed with a two-way ANOVA. Results Green and red fluorescence was used to represent the PGs and the CF that were colocalized in the same section with different distributions. PGs were localized in the lumens of the dentin tubules and in peritubular dentin, while the type-I collagen fibrils were localized in intertubular dentin and peritubular dentin. After preconditioning with TRY digestion, the red fluorescence decreased or disappeared, the organic filaments in the lumens of the dentin tubules disappeared, the tubules were enlarged, and the hybrid layer thickness for adhesives bonded to the TRY-pretreated dentin surfaces were significantly increased (p < 0.001 for both SB and PBNT). Significance The dual immunofluorescence labeling methodology can be used to study the human dentin matrix without decalcifying the entire dentin fragment. Proteoglycans were localized in the lumens of the dentin tubules and in peritubular dentin, which could depress the infiltration of the adhesive resin monomers. The use of TRY digestion increased the thickness of the hybrid layer created by the tested two-step etch-and-rinse adhesive.
    Dental Materials. 01/2014;
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    ABSTRACT: To evaluate the effect of luting cement and thermomechanical loading on the retention of glass fibre posts in root canals. One hundred and forty-four single-rooted human premolars were endodontically treated and restored with RelyX Fiber Posts. The teeth were divided into four groups according to the cements used (Fuji I, Fuji CEM, RelyX Unicem and RelyX ARC). Each group was further divided into two subgroups according to the method of ageing (immediately-tested and after thermomechanical loading). Bond strength was evaluated using a pull-out test. Microleakage was examined quantitatively with dye penetration. The dentine-cement-post bonding interface was assessed using scanning electron microscopy. Data were analysed with two-way ANOVA (pull-out test) and Kruskal-Wallis analysis (microleakage). The pull-out bond strength and microleakage were significantly affected by the type of cement and ageing. Although RelyX ARC showed the highest bond strength before thermomechanical loading (p<0.05), the sealing ability of this cement was worse than those exhibited in Fuji CEM and RelyX Unicem (p<0.05). After thermomechanical loading, pull-out strengths of Fuji I and Fuji CEM were significantly increased, whereas that of RelyX ARC group significantly decreased (p<0.05). The sealing ability of Fuji CEM was significantly better than the two resin cement groups (p<0.05) after ageing. Fuji CEM demonstrates increased pull-out strength after thermomechanical loading and favourable sealing ability compared with the other cements. Resin-modified glass ionomer cements have the potential benefit of achieving long-term retention when used for luting glass fibre post to root canal dentine. So it may be recommended for the cementation of glass fibre post in clinics.
    Journal of dentistry 11/2013; · 3.20 Impact Factor
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    ABSTRACT: Purpose: To introduce a new fixation method for stick-shaped specimens for use in microtensile tests and to evaluate the effect of this new method on microtensile bond strength, failure modes, and stress distribution. Materials and Methods: Flat mid-coronal dentin surfaces were prepared on 12 caries-free human third molars and randomly divided into two groups for testing with two dental adhesives (Adper Single Bond 2 [SB2] and Clearfil SE Bond [SEB]). Following adhesive application and composite buildups, the bonded teeth were sectioned into beams. Sticks from each tooth were then equally divided into two subgroups for microtensile bond testing according to the utilized gripping devices (a flat Ciucchi's jig and the experimental setup). Failure modes were examined with a field-emission scanning electron microscope (FESEM). Three-dimensional models of each gripping device and specimen were developed, and stress distributions were analyzed by finite element analysis (FEA). Statistical significance was set at α = 0.05 Results: Compared to those fixed using a flat Ciucchi's jig, sticks fixed with the experimental setup yielded lower bond strength values (p = 0.021 for SB2 and p = 0.007 for SEB) and more mixed failure patterns (p = 0.036 for both SB2 and SEB). In addition, the experimental setup guaranteed a uniaxial tensile force that was perpendicular to the bonding interface and produced a more uniform stress distribution at the bonding interface. Conclusion: An experimental setup for fixing microtensile sticks was proposed that was designed to provide a uniform stress distribution at the adhesive interface. FEA and failure mode analysis confirmed such uniform distribution, thus supporting the validity of the bond strength results obtained with this new fixture design.
    The journal of adhesive dentistry 04/2013; · 0.91 Impact Factor
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    ABSTRACT: To investigate the potential effect of proanthocyanidins (PA), a natural cross-linker, on the stability of resin-dentin bonds against thermal cycling. Ten percent, 15% PA-based preconditioners, and 5% glutaraldehyde were prepared for the transient pretreatment of demineralized dentin before bonding. Specimens without pretreatment were used as negative controls (n = 4 teeth for each group). Microtensile bond strength, failure mode, micromorphologies of resin-dentin interface and the collagen degradation of bonded specimens after thermal cycling were evaluated. After thermal cycling, the microtensile bond strength values of resin-dentin bond in groups pretreated with 15% PA for 120 s and 60 s [(23.09 ± 3.19) and (21.88 ± 3.49) MPa] were significantly higher than that in control group [(15.47 ± 3.78) MPa] (P < 0.05). Mixed fractures were the most prevalent failure mode. Specimens with pretreatment presented compact hybrid layer, while some narrow gaps were found in hybrid layer of non-treated specimens. Collagen biodegradation rates in groups with pretreatment were significantly lower than that in control group (P < 0.05). Among them, specimens pretreated by 15% PA preconditioner for 120 s exhibited the lowest biodegradation rates [(0.316 ± 0.019) mg/g]. The application of natural cross-linker PA on demineralized dentin reduced the bond degradation against aging by thermal cycling, and can be helpful to create more durable bonds to dentin.
    Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology 05/2012; 47(5):268-72.
  • San-Jun Zhao, Jian-Wei Sun, Ji-Hua Chen
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    ABSTRACT: To evaluate the dentin and enamel bonding strength and resin-dentin interfaces of four resin cements. Twenty-four sound freshly extracted molars were sectioned with low-speed saw under running water. Two mesial-distal enamel disc and two buccal-lingual dentin discs were sectioned from each molar. Four resin cements (A group: Panavia(TM) F; B group: RelyX(TM) ARC; C group: RelyX(TM) Unicem; D group: Clearfil(TM) SA Cement) were applied to the surface of these enamel and dentin discs according to manufacturers' guidance. The bonded specimen were prepared for shear bond strength test and sectioned occluso-gingivally into two slabs for scanning electron microscopy (SEM) observation. The bonding strength between resin and enamel in B group [(29.38 ± 6.28) MPa] was higher than that in D group [(27.25 ± 7.03) MPa], and both of them were significantly higher than those in A [(22.92 ± 7.13) MPa] and C group [(10.92 ± 3.41) MPa] (P < 0.05). The highest dentin bonding strength was shown in B group [(27.28 ± 6.79) MPa], followed by A [(14.23 ± 6.39) MPa], D [(10.09 ± 3.26) MPa] and C group [(6.43 ± 1.60) MPa, P < 0.05]. The four resin cements have different enamel or dentin bonding properties.
    Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology 01/2011; 46(1):38-41.
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    ABSTRACT: To evaluate the effect of etching time on the nanoleakage and microtensile bond strength (microTBS) at the interface between etch-and-rise adhesives and dentin. Eighty molars were sectioned to expose the superficial dentin and randomly divided into four groups according to the adhesives used: OptiBond Solo (OB), Single Bond (SB), One-Step (OS), and Prime&Bond NT (PB). Within each group, a total-etching technique was applied, and the dentin surfaces were etched for 0, 15, 30 or 60 seconds. Each treated tooth was then sectioned into sticks. A non-trimming microTBS test and TEM observation for nanoleakage were sequentially performed. The degree of nanoleakage increased as etching time increased (P < 0.05). For the OS and PB groups, the highest microTBS values were achieved with 15 seconds of etching, followed by 30, 60 and 0 seconds. For the OB and SB groups, the microTBS values for 15- and 30-second etching times were similar and were both significantly higher than those of 0 and 60 seconds (P < 0.05).
    American journal of dentistry 12/2010; 23(6):335-40. · 1.06 Impact Factor
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    ABSTRACT: Antibacterial activities have been demonstrated on oral bacteria with inorganic antibacterial agents (ABAs) after their incorporations into an experimental self-etching primer (ESP) before curing. This study was to assess their biocompatibility and antibacterial activity after curing. Six ABAs were incorporated respectively into ESP for treating specimens. After curing, their bactericidal activities on Streptococcus mutans and influences to the early bacterial colonization were assessed by direct contact and viable count. Systemic toxicity in rats after short-term oral exposure and direct contact cytotoxicity with NIH3T3 fibroblasts were tested. Incorporation of ZnOw AT-83, Longbei antibiotic, Antim-AMS2 or IONPURE-H significantly enhanced the antibacterial effect of ESP after curing, even after 1 month aging. Specimens treated by ESP with ZnOw AT-83, Longbei antibiotic or Antim-AMS2 showed slightly less bacterial adhesion than control. Animal experiments revealed neither toxic signs nor significant differences in body weight gain between control and other groups. Cell vitality or proliferation rates were ranged from 76% to 100% with respect to controls. Basic magnesium hypochlorite, ZnOw AT-83 and ZnOw AT-88 were less toxic. Toxicity only observed in areas beneath the specimens and/or in the direct vicinity of the specimen edge. From microbiological and biocompatibility aspects, the tested ABAs can be effectively incorporated in ESP to provide antibacterial activity against S. mutans. ZnOw AT-83 was the most promising one.
    Biomolecular Engineering 12/2007; 24(5):483-8. · 3.17 Impact Factor
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    ABSTRACT: To measure the spectral transmittance of Cerinate porcelain veneer and enamel in different color and different thickness. Samples of Cerinate porcelain veneers were prepared in different thickness (0.50 mm, 0.75 mm, 1.00 mm) and different Vita shade (A1, A2, A3). Enamel samples in shade A2 were made with three thickness (0.50 mm, 0.75 mm, 1.00 mm). A spectrophotometer with spectra range (380-800 nm) was employed to measure the spectral transmittance. Spectral transmittance decreased with the increasing in the thickness of specimens and decreasing in the color darkness. The transmittance of Cerinate porcelain veneer material and enamel in the same color and same thickness hadn't significant difference. The key factor to spectral transmittance of porcelain veneer materials is veneer's thickness, and the color of the materials has also some influence on it. Cerinate porcelain veneers can properly recover the transparency of teeth.
    Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology 01/2007; 24(6):513-5.
  • San-jun Zhao, Ji-hua Chen, Wei Wu, Yu Xiong
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    ABSTRACT: To evaluate the nanoleakage appearance in 6 dentin adhesives. Superficial occlusal dentin of 12 human molars without caries extracted freshly was exposed with 600-grit SiC papers under running water. Six adhesives were applied to dentin surfaces according to the manufacturers' instructions. The bonded teeth were sectioned occluso-gingivally into 0.9-mm-thick serial slabs that were stored in ammoniacal silver nitrate solution in the dark for 24 h and prepared for transmission electron microscope. The extent of nanoleakage among 6 dentin adhesives was measured and compared using one-way ANOVA. The nanoleakage was observed obviously at the dentin-resin interfaces of all 6 adhesives. The average dentin nanoleakage values of Group A [BangDuo, (16.09 +/- 2.08)%], Group B [Single Bond, (13.39 +/- 1.81)%], and Group C [Prime&Bond NT, (11.27 +/- 1.94)%] were all significantly different (P < 0.05). There was no significant difference in the dentin nanoleakage between Group D [B(1), (12.13 +/- 2.11)%] and Group E [Clearfil SE Bond, (12.35 +/- 2.60)%], but both of them were lower than Group F [Adper Prompt, (14.93 +/- 2.67)%]. The nanoleakage phenomena at the dentin-resin interface were all observed diversely in the contemporary dental adhesives.
    Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology 11/2005; 40(6):500-3.
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    ABSTRACT: The purpose of this study was to evaluate the clinical result of 546 tetracycline-stained teeth restored with a porcelain laminate veneer system (Cerinate, Den-Mat, USA) for aesthetic reasons. Tetracycline-stained teeth (546) were restored with a porcelain veneer system, and bonded with Ultra Bond resin cement. The restorations were recalled after 0.5, 1.5 and 2.5 years, respectively. Modified Ryge criteria were used to evaluate the veneers marginal adaptation, interfacial staining, secondary caries, postoperative sensitivity and the patients' satisfaction of the colour of the restorations. This study found that 99% veneers had excellent marginal adaptations; and less than 1% veneers required rebonding in the first 6 months; the colour of the veneers was stable and no evident staining was found. Almost all patients were satisfied with the colour match of their restorations 1 year after placement. The research indicated that the porcelain veneer restoration system under investigation provided a reliable and highly satisfactory choice for the aesthetic restoration of tetracycline-stained teeth.
    Journal of Dentistry 02/2005; 33(1):3-8. · 3.20 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the clinical result of 546 tetracycline-stained teeth corrected with Cerinate porcelain laminate veneer system for esthetic purpose. 546 tetracycline-stained teeth were corrected with Cerinate porcelain veneer system, and bonded with Ultra Bond resin cement. The restorations were recalled after 0.5 year, 1.5 years and 2.5 years, respectively. modified Ryge criteria were used to evaluate the veneers marginal adaptation, interfacial staining, secondary caries, postoperative sensitivity and the patients' satisfaction with the shade of the restorations. this study found that 99% veneers had excellent marginal adaptations; and less than 1% veneers were rebonded after debond in the first half year application; the color of the veneers was stable and no evident staining was found. Almost all patients were satisfied with their restoration color after 1 year's application. The research indicated that Cerinate porcelain veneer restoration system is a reliable and ideal choice for the correction of tetracycline-stained teeth.
    Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology 06/2003; 38(3):199-202.
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    ABSTRACT: Purpose: To observe the effect of acid etching time on nanoleakage and microtensile bond strength (µTBS) of the adhesive-dentin bond with different total-etch adhesive systems. Materials and Methods Eighty human molars, whose occlusal enamel was removed to expose the dentin surfaces, were conditioned with phosphoric acid for 0 (control), 15, 30 or 60 s (n=20). Resin-dentin bonded specimens were produced using four one-bottle adhesives respectively; OptiBond Solo (OB), Single Bond (SB), One-Step (OS), and Prime & Bond NT (PB). Each specimen was then sectioned perpendicularly to the adhesive interface into eight beams. Four were used to measure the nanoleakage of adhesive-dentin interface by transmission electron microscope and four to conduct the µTBS test. The data was collected and statistically compared with analysis of variance and post-hoc test. Results: Nanoleakage increased with increasing etching time (0, 15, 30, and 60 s; p<0.05). For the OS and PB groups, the highest µTBS were achieved after 15 s of etching, followed by 30, 60, and 0 s. For the OB and SB groups, the µTBS between 15 and 30 s etching time subgroups were not significantly different between them but significantly higher than those of 0 and 60 s etching time subgroups (p<0.05). Conclusion: Increasing etching time demineralized the dentin surface to a depth greater than adhesives can penetrate, resulting in more nanoleakage and lower µTBS. (Int Chin J Dent 2006; 6: 29-37.) Key Words: dentin, etching time, nanoleakage, microtensile bond strength.

Publication Stats

27 Citations
14.42 Total Impact Points

Institutions

  • 2005–2014
    • Fourth Military Medical University
      • • Department of Prosthodontics
      • • School of Stomatology
      Xi’an, Liaoning, China