[Cloning and expression analysis of U6 promoters in Panax quinquefolius].

The U6 promoter is an important element driving sgRNA transcription in the CRISPR/Cas9 system. Seven PqU6 promo-ter sequences were cloned from the gDNA of Panax quinquefolium, and the transcriptional activation ability of the seven promoters was studied. In this study, seven PqU6 promoter sequences with a length of about 1 300 bp were cloned from the adventitious roots of P. quinquefolium cultivated for 5 weeks. Bioinformatics tools were used to analyze the sequence characteristics of PqU6 promoters, and the fusion expression vectors of GUS gene driven by PqU6-P were constructed. Tobacco leaves were transformed by Agrobacterium tumefaciens-mediated method for activity detection. The seven PqU6 promoters were truncated from the 5'-end to reach 283, 287, 279, 289, 295, 289, and 283 bp, respectively. The vectors for detection of promoter activity were constructed with GUS as a reported gene and used to transform P. quinquefolium callus and tobacco leaves. The results showed that seven PqU6 promoter sequences(PqU6-1P to PqU6-7P) were cloned from the gDNA of P. quinquefolium, with the length ranged from 1 246 bp to 1 308 bp. Sequence comparison results showed that the seven PqU6 promoter sequences and the AtU6-P promoter all had USE and TATA boxes, which are essential elements affecting the transcriptional activity of the U6 promoter. The results of GUS staining and enzyme activity test showed that all the seven PqU6 promoters had transcriptional activity. The PqU6-7P with a length of 1 269 bp had the highest transcriptional activity, 1.31 times that of the positive control P-35S. When the seven PqU6 promoters were truncated from the 5'-end(PqU6-1PA to PqU6-7PA), their transcriptional activities were different in tobacco leaves and P. quinquefolium callus. The transcriptional activity of PqU6-7PA promoter(283 bp) was 1.59 times that of AtU6-P promoter(292 bp) when the recipient material was P. quinquefolium callus. The findings provide more ideal endogenous U6 promoters for CRISPR/Cas9 technology in ginseng and other medicinal plants.

Stimulation phosphatidylinositol 3-kinase/protein kinase B signaling by Porphyromonas gingivalis lipopolysacch aride mediates interleukin-6 and interleukin-8 mRNA/protein expression in pulpal inflammation.

BACKGROUND/PURPOSE: The signaling mechanisms for Porphyromonas gingivalis lipopolysaccharide (PgLPS)-induced inflammation in human dental pulp cells are not fully clarified. This in vitro study aimed to evaluate the involvement of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway in PgLPS-induced pulpal inflammation. METHODS: Human dental pulp cells (HDPCs) were challenged with PgLPS with or without pretreatment and coincubation with a PI3K/Akt inhibitor (LY294002). The gene or protein levels of PI3K, Akt, interleukin (IL)-6, IL-8, alkaline phosphatase (ALP), osteocalcin and osteonectin were analyzed by reverse transcription polymerase chain reaction (PCR), real-time PCR, western blotting, and immunofluorescent staining. In addition, an enzyme-linked immunosorbent assay was used to analyze IL-6 and IL-8 levels in culture medium. RESULTS: In response to 5 µg/ml PgLPS, IL-6, IL-8, and PI3K, but not Akt mRNA expression of HDPCs, was upregulated. IL-6, IL-8, PI3K, and p-Akt protein levels were stimulated by 10-50 µg/ml of PgLPS in HDPCs. PgLPS also induced IL-6 and IL-8 secretion at concentrations higher than 5 µg/ml. Pretreatment and co-incubation by LY294002 attenuated PgLPS-induced IL-6 and IL-8 mRNA expression in HDPCs. The mRNA expression of ALP, but not osteocalcin and osteonectin, was inhibited by higher concentrations of PgLPS in HDPCs. CONCLUSION: P. gingivalis contributes to pulpal inflammation in HDPCs by dysregulating PI3K/Akt signaling pathway to stimulate IL-6 and IL-8 mRNA/protein expression and secretion. These results are useful for understanding the pulpal inflammation and possible biomarkers of inflamed pulp diagnosis and treatment.

Physicochemical, functional and antioxidant properties of mung bean protein enzymatic hydrolysates.

This study aimed to investigate physicochemical, functional and antioxidant properties of mung bean protein (MBP) enzymatic hydrolysates (MBPEHs) by alcalase, neutrase, protamex, flavourzyme and papain. Physicochemical properties were evaluated by SDS-PAGE, particle size distribution, FTIR, ultraviolet visible and fluorescence spectrophotometries. ABTS, hydroxyl scavenging, Fe2+ chelating activity were used to evaluate antioxidant activity. Enzymolysis with five proteases decreased average particle size, α-helix, ß-sheet, surface hydrophobicity of hydrolysates. Alcalase hydrolysate had the highest degree of hydrolysis (23.55%), absolute zeta potential (33.73 mV) and the lowest molecular weight (<10 kDa). Protamex and papain hydrolysates had higher foaming capacities, emulsification activity indexes, emulsion stability indexes (235.00%, 123.07 m2/g, 132.54 min; 200.10%, 105.39 m2/g, 190.67 min) than MBP (135.03%, 20.03 m2/g, 30.88 min). Alcalase hydrolysate demonstrated the lowest IC50 (mg/mL) in ABTS (0.12), hydroxyl (2.98), Fe2+ chelating (0.22). These results provide support for application of MBPEHs as foaming agent, emulsifier and antioxidant in food industry.

Dental technology of Taiwan during the Japanese colonial period.

Background/purpose: During the Japanese colonial period, the Taipei Hospital had already provided complete dental services with a fixed price per treatment. This study tried to compare the differences in the prices of various dental treatments between the Japanese colonial period and today. Materials and methods: This study used the "Dental Treatment Fees in the 27th Annual Report of Taipei Hospital (Taisho 12)" as the study materials to compare the differences in the prices of various dental treatments between the Japanese colonial period and today using the monthly salary of a novice elementary school teacher as an income benchmark. Results: A hundred years ago, the Taipei Hospital had already provided the dental treatments such as scaling and endodontic, operative dentistry, prosthodontic, and orthodontic treatments. Of these treatment items, the prices for prosthodontic and orthodontic treatments were more expensive. After a century of development, the costs of scaling and operative dentistry treatments dropped, while the costs of endodontic, prosthodontic, and orthodontic treatments increased. Conclusion: During the Japanese colonial period, Taiwan's dental treatment technology had already had the forms of modern dentistry with several dental specialties. At that time, the costs of dental treatments are quite expensive. Today's dental treatment items are more detailed and diverse. The health insurance system provides Taiwanese people with convenient and cheap general dental treatments such as scaling and treatments related to operative dentistry, endodontics, periodontics, and oral surgery. However, the costs of prosthodontic and orthodontic treatments increase and have to be paid by the patients themselves.

Influence of ultrasound treatment on the physicochemical and antioxidant properties of mung bean protein hydrolysate.

This study aimed to investigate influence of ultrasonic treatment on physicochemical and antioxidant properties of mung bean protein hydrolysate (MPH). Physicochemical properties of MPH were evaluated by Tricine-SDS-PAGE, particle size distribution, fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy, among others. Radicals scavenging activities of ABTS, hydroxyl, superoxide anion, Fe2+ chelating ability and reducing power characterized antioxidant activities of MPH. MPH contained four bands of 25.6, 12.8, 10.6 and 4.9 kDa, in which 4.9 kDa was the most abundant. Ultrasonic treatment increased the contents of aromatic and hydrophobic amino acids in MPH. Ultrasonic treatment decreased the content of α-helix of MPH and increased ß-sheet and ß-turn compared to MPH. MPH-546 W (ultrasonic treatment 546 W, 20 min) had the lowest average particle size (290.13 nm), zeta potential (-36.37 mV) and surface hydrophobicity (367.95 A.U.). Antioxidant activities of ultrasonicated-MPH increased with the ultrasonic power, achieving the lowest IC50 (mg/mL) of 0.1087 (ABTS), 1.796 (hydroxyl), 1.003 (superoxide anion) and 0.185 (Fe2+ chelating ability) in 546 W power. These results indicated ultrasonic treatment would be a promising method to improve the antioxidant properties of MPH, which would broaden the application scope of MPH as bioactive components in the food industry.

Dental manpower and treated dental diseases in department of dentistry, Taipei Hospital (the predecessor of National Taiwan University Hospital) in 1923.

BACKGROUND/PURPOSE: In 1906, there was a dental treatment room established in the department of surgery of Taipei Hospital to introduce modern dental services to Taiwan. It is undoubtedly the earliest hospital dentistry in Taiwan. This study tried to assess the dental manpower and treated dental diseases in Taipei Hospital, and hence to explore the appearance of Taiwan's early hospital dentistry. MATERIALS AND METHODS: This study utilized the secondary data analysis to evaluate the dental manpower and treated dental diseases of dental outpatients in the 27th Annual Report of Taipei Hospital (Taisho 12th year or 1923). RESULTS: Our results found that there were 3 dentists and one dental technician in the dental department of Taipei Hospital in 1923. These 3 dentists totally treated 3 inpatients and 1759 outpatients with 4511 outpatient visits (1959 for male patients and 2552 for female patients) in that year. Dental caries and retained root were the two most common dental diseases in Japanese and Taiwanese dental outpatients, and followed in a descending order by missing tooth, pulp necrosis, and pulpitis for Japanese outpatients as well as pulpitis, suppurative periodontitis, and acute or chronic periodontitis for Taiwanese outpatients. CONCLUSION: We conclude that the dentistry of Taipei Hospital in 1923 does have a modern form of dentistry with 3 dentists and one dental technician. Its dental patients are mainly Japanese and minorly Taiwanese. Moreover, the treated dental diseases are mainly tooth diseases for Japanese outpatients and both tooth and periodontal diseases for Taiwanese outpatients.

Physicochemical properties and antioxidant activities of tree peony (Paeonia suffruticosa Andr.) seed protein hydrolysates obtained with different proteases.

The physicochemical and antioxidant properties of tree peony seed protein (TPSP) hydrolysates by Alcalase, Neutrase, Papain, Protamex, and Flavourzyme were investigated in this study. The physicochemical properties were characterized by SDS-PAGE, particle size distribution, fourier transform infrared and fluorescence spectroscopy etc. The antioxidant activities were determined by DPPH radical, ABTS radical, Fe2+ chelating, and reducing power. The results showed five proteases produced hydrolysates with a significantly reduced average particle size, α-helices, and surface hydrophobicity compared to TPSP. Alcalase and Neutrase hydrolysis enhanced the nutritional value of the hydrolysates. Alcalase hydrolysates possessed the highest degree of hydrolysis (27.97%) and lowest molecular weight (<13 kDa) with average particle size (231.33 nm). Alcalase hydrolysate displayed the highest radical scavenging (DPPH IC50 = 0.18 mg/mL, ABTS IC50 = 1.57 mg/mL), Fe2+ chelating activity (IC50 = 0.99 mg/mL), and reducing power (0.594). These results provide the fundamentals for TPSP hydrolysates as antioxidants to be employed in food industry or pharmaceutical industry.

Association of initial mucogingival status with clinical outcome of non-surgical periodontal therapy: A retrospective analysis of 204 patients.

BACKGROUND/PURPOSE: This study was conducted to evaluate the influence of mucogingival parameters, including keratinized mucosa (KM) and attached gingiva (AG), on the outcome of non-surgical periodontal therapy (NSPT). METHODS: A total of 204 non-smoking patients with generalized chronic periodontitis who received NSPT between 2012 and 2014 were included. The Mantel-Haenszel chi-square test was used to assess the associations between initial mucogingival parameters and initial clinical parameters on the buccal aspect, and the associations between initial mucogingival parameters and outcome clinical parameters on the buccal aspect of the sites with severe periodontal destruction. The generalized liner model was used to evaluate the contribution of initial clinical parameters to the outcome of NSPT. RESULTS: KM ≥ 3 mm was associated with greater probing pocket depth (PD), less gingival recession (REC), and less clinical attachment level (CAL), and AG < 1 mm was associated with greater PD, REC, and CAL before NSPT. At the sites with severe periodontal destruction, KM ≥ 3 mm was associated with greater PD reduction (0.25 ± 0.08 mm) and CAL gain (0.25 ± 0.09 mm), and AG < 1 mm was associated with greater CAL gain (0.15 ± 0.08 mm) after NSPT. Initial PD ≥ 7 mm and non-molar teeth showed greater contribution to the outcome of NSPT. CONCLUSION: Less AG (<1 mm) was associated with greater periodontal destruction at baseline. At the sites with severe periodontal destruction, greater KM (≥3 mm) and less AG (<1 mm) resulted in better outcomes of NSPT.

Curcumin inhibits TGF-ß1-induced connective tissue growth factor expression through the interruption of Smad2 signaling in human gingival fibroblasts.

BACKGROUND/PURPOSE: Many fibrotic processes are associated with an increased level of transforming growth factor-ß1 (TGF-ß1). TGF-ß1 can increase synthesis of matrix proteins and enhance secretion of protease inhibitors, resulting in matrix accumulation. Connective tissue growth factor (CTGF) is a downstream profibrotic effector of TGF-ß1 and is associated with the fibrosis in several human organs. Curcumin has been applied to reduce matrix accumulation in fibrotic diseases. This study was aimed to evaluate whether curcumin could suppress TGF-ß1-induced CTGF expression and its related signaling pathway involving in this inhibitory action in primary human gingival fibroblasts. METHODS: The differences in CTGF expression among three types of gingival overgrowth and normal gingival tissues were assessed by immunohistochemistry. Gingival fibroblast viability in cultured media with different concentrations of curcumin was studied by MTT assay. The effect of curcumin on TGF-ß1-induced CTGF expression in primary human gingival fibroblasts was examined by immunoblotting. Moreover, the proteins involved in TGF-ß1 signaling pathways including TGF-ß1 receptors and Smad2 were also analyzed by immunoblotting. RESULTS: CTGF was highly expressed in fibroblasts, epithelial cells and some of endothelial cells, smooth muscle cells, and inflammatory cells in phenytoin-induced gingival overgrowth tissues rather than in those of hereditary and inflammatory gingival overgrowth tissues. Moreover, CTGF expression in the epithelial and connective tissue layers was higher in phenytoin-induced gingival overgrowth tissues than in normal gingival tissues. Curcumin was nontoxic and could reduce TGF-ß1-induced CTGF expression by attenuating the phosphorylation and nuclear translocation of Smad2. CONCLUSION: Curcumin can suppress TGF-ß1-induced CTGF expression through the interruption of Smad2 signaling.

Summative objective structured clinical examination as a reference of learners' need before entering their internship.

BACKGROUND/PURPOSE: Objective structured clinical examination (OSCE) has found increasingly wide use in the education of clinical dentistry in recent years. The objectives of this study were to find the predictability of OSCE in representing a student's actual ability in a clinical environment and to provide instructors with better ideas to guide an individual student in a certain field. MATERIALS AND METHODS: Thirty-one dentistry students' qualification OSCE scores were obtained after the conclusion of their dental clerkship in December 2014. The OSCE scores were compared with the various scores given by instructors from different departments during their internship a year later. The correlation was investigated between these two scores. RESULTS: The scores of the first station of OSCE-explaining a treatment plan for the restoration of a missing tooth-were correlated with the scores of prosthodontics in the internship. The scores of the fourth station of OSCE-explaining to a mother regarding the obtainment of a radiograph of her child's tooth-were correlated with the scores of orthodontics. In addition, the total score of the six OSCE stations was correlated with the scores of orthodontics, oral surgery, and pediatric dentistry during dental internship. CONCLUSION: The results of clerkship qualification OSCE could provide instructors with insights into the needs of the students before their entering internship.

Significant association of rheumatoid arthritis-related inflammatory markers with non-surgical periodontal therapy.

BACKGROUND/PURPOSE: Chronic periodontitis (CP) and rheumatoid arthritis (RA) are the most common chronic inflammatory diseases and their immunopathogenesis is similar. The aim of this study was to evaluate the effect of non-surgical periodontal treatment on the serum levels of RA-related inflammatory markers in patients with chronic periodontitis. METHODS: Thirty-one Taiwanese adults with CP were included. Demographics and periodontal parameters, including probing depth, clinical attachment level, and number of remaining teeth in the oral cavity, were recorded. All subjects received non-surgical periodontal treatment such as scaling and subgingival root planing. Serum samples were collected before and after the treatment. Serum levels of anti-citrullinated protein antibodies (ACPA), rheumatoid factor, tumor necrosis factor-α (TNF-α), C-reactive protein, interleukin-1ß (IL-1ß), and Interleukin-6 (IL-6) were measured using an enzyme-linked immunosorbent assay. RESULTS: Non-surgical periodontal treatment significantly reduced the serum ACPA (p = 0.015) and TNF-α levels (p = 0.026) in CP patients, particularly in patients with generalized CP. Furthermore, there was a significant and positive correlation between the number of extracted teeth and the reduction in the serum ACPA (p = 0.05) and IL-1ß levels (p = 0.029) after non-surgical periodontal treatment. CONCLUSION: Non-surgical periodontal therapy may aid in the control of RA-related inflammatory markers in patients with CP. A large-scale study with well-defined populations is needed to clarify the benefit of non-surgical periodontal therapy.

Lasers in minimally invasive periodontal and peri-implant therapy.

Laser therapy has the potential to be an effective, minimally invasive procedure in periodontal therapy. The aim of the present review was to survey the relevant literature on the clinical application of lasers as a minimally invasive treatment for periodontitis and peri-implant disease. Currently, there are a large number of published clinical studies and case reports that evaluate the adjunctive use of diode, carbon dioxide, neodymium-doped yttrium aluminium garnet (Nd:YAG), erbium-doped yttrium aluminium garnet (Er:YAG) and erbium, chromium-doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) lasers or antimicrobial photodynamic therapy for nonsurgical and minimally invasive surgical treatment of periodontal pockets. These procedures are expected not only to control inflammation but also to provide biostimulation effects with photonic energy. Recent meta-analyses did not show statistically significant differences in pocket reduction and clinical attachment gain compared with mechanical debridement alone, although limited positive effects of adjunctive laser therapy were reported. At present, systematic literature approaches suggest that more evidence-based studies need to be performed to support the integration of various laser therapies into the treatment of periodontal and peri-implant diseases. The disparity between previous statistical analyses and individual successful clinical outcomes of laser applications might reveal the necessity of developing optimal laser-treatment modalities of different wavelengths and better-defined indications for each protocol.

Light-emitting diode irradiation promotes donor site wound healing of the free gingival graft.

BACKGROUND: This study aims to evaluate the effect of light-emitting diode (LED) light irradiation on the donor wound site of the free gingival graft. METHODS: Rat gingival fibroblasts were chosen to assess the cellular activities and in vitro wound healing with 0 to 20 J/cm(2) LED light irradiation. Seventy-two Sprague-Dawley rats received daily 0, 10 (low-dose [LD]), or 20 (high-dose [HD]) J/cm(2) LED light irradiation on the opened palatal wound and were euthanized after 4 to 28 days; the healing pattern was assessed by histology, histochemistry for collagen deposition, and immunohistochemistry for tumor necrosis factor (TNF)-α infiltration. The wound mRNA levels of heme oxygenase-1 (HO-1), TNF-α, the receptor for advanced glycation end products, vascular endothelial growth factor, periostin, Type I collagen, and fibronectin were also evaluated. RESULTS: Cellular viability and wound closure were significantly promoted, and cytotoxicity was inhibited significantly using 5 J/cm(2) LED light irradiation in vitro. The wound closure, reepithelialization, and collagen deposition were accelerated, and sequestrum formation and inflammatory cell and TNF-α infiltration were significantly reduced in the LD group. HO-1 and TNF-α were significantly upregulated in the HD group, and most of the repair-associated genes were significantly upregulated in both the LD and HD groups at day 7. Persistent RAGE upregulation was noted in both the LD and HD groups until day 14. CONCLUSION: LED light irradiation at 660 nm accelerated palatal wound healing, potentially via reducing reactive oxygen species production, facilitating angiogenesis, and promoting provisional matrix and wound reorganization.

Osseous wound repair under inhibition of the axis of advanced glycation end-products and the advanced glycation end-products receptor.

BACKGROUND/PURPOSE: Blockade of advanced glycation end-products (AGE) is able to reduce diabetic complications and control periodontitis. This study aimed to determine whether the application of aminoguanidine (AG), an AGE inhibitor, or N-phenacylthiazolium bromide (PTB), an AGE breaker, facilitates the healing of an osseous wound in non-diabetic animals. METHODS: 2.6 mm diameter full-thickness osseous wounds were created bilaterally in 54 healthy Sprague-Dawley rats. Rats received daily normal saline, AG, or PTB injections respectively and were euthanized after 7 days, 14 days, or 28 days (n = 6). The wound healing pattern was assessed by micro-computed tomography, histology, histochemistry for the fiber arrangement, and the gene expression levels of AGE receptor, tumor necrosis factor-α, type I collagen, and fibronectin. RESULTS: Under the AG and PTB administration, osteogenesis was apparently promoted in the early stages of healing, but the union of the osseous wound and the fibril re-arrangement was apparently retarded. No significant difference was found in any of the micro-computed tomography parameters as compared to the control in the first 14 days, whereas the relative bone volume was significantly higher in the control at Day 28. AGE receptor and tumor necrosis factor-α were depressed in the PTB group, but only temporarily at Day 14 in the AG group. Therefore, at Day 14, type I collagen was significantly upregulated in the PTB group, and fibronectin was significantly increased in the AG group. CONCLUSION: Anti-AGE agents reduced inflammation but did not apparently facilitate osteogenesis during the osseous wound repair.

Combination of LED light and platelet-derived growth factor to accelerate dentoalveolar osteogenesis.

AIM: This study aimed to evaluate the adjunctive effect of LED light in platelet-derived growth factor (PDGF)-aided dentoalveolar osteogenesis. MATERIAL AND METHODS: Full-thickness osseous wounds were created on rat maxillae and were either unfilled or filled with poly-(D,L-lactide) and poly-(D,L-lactide-co-glycolide) microspheres encapsulating PDGF. Animals received daily 660 ± 25 nm LED light irradiation at 0, 10 (LD), or 20 (HD) J/cm(2) , were killed at days 4-28 (n = 6/group/time) and evaluated by microcomputed tomography (micro-CT), histology, and the expressions of osteopontin and tartrate-resistant acid phosphatase (TRAP). RESULTS: Greater osteogenesis was noted in the PDGF-treated defects at day 14. Under the LED light irradiation, osteogenesis was significantly greater in both LD and HD groups of the non-PDGF-treated defects, but only in the LD group of the PDGF-treated defects. No significant differences in osteogenesis among groups were noted at day 28. Greater bone marrow space was noted in the LED light-irradiated specimens, especially in the PDGF-treated defects at both time points. Osteopontin was significantly promoted in the LD group at both time points, and TRAP was significantly promoted in all LED light-irradiated groups at day 28. CONCLUSION: LED light could an adjunct to promote early PDGF-aided dentoalveolar osteogenesis by facilitating the osteoblast-osteoclast coupling.

Epigallocatechin-3-gallate inhibits lysophosphatidic acid-stimulated connective tissue growth factor via JNK and Smad3 suppression in human gingival fibroblasts.

BACKGROUND/PURPOSE: Connective tissue growth factor (CTGF/CCN2) is involved in the development and progression of fibrotic diseases, including gingival overgrowth (GO). Recent studies indicate that lysophosphatidic acid (LPA) is also significantly involved in wound healing and the development of fibrosis. This study investigated whether epigallocatechin-3-gallate (EGCG) can inhibit LPA-induced CCN2 expression in human gingival fibroblast (GF) and its mechanism. METHODS: Western blot analyses were used to study the signaling pathways of LPA-induced CCN2 expression in human GFs and the effects of EGCG on this pathway. RESULTS: LPA stimulated CCN2 synthesis in human GFs. This effect can be significantly inhibited bytransforming growth factor-ß type I receptor/ALK5, Smad3, and JNK inhibitors but not ERK, P38, and MAPK inhibitors. EGCG completely inhibited LPA-induced CCN2 expression through attenuating the LPA-induced JNK and Smad3 phosphorylation in human GFs. CONCLUSION: LPA produced at the surgical wound may contribute to the recurrence of GO by upregulating CCN2 expression in human GFs. This effect was mediated by Smad3 and JNK activation and ALK5 transactivation. EGCG could be a useful agent for reducing the recurrence of GO after surgery through suppression of JNK and Smad3 activations.

Influence of etching ability of one-step self-etch adhesives on bonding to sound and non-carious cervical sclerotic dentin.

The purpose of this study was to evaluate influence of etching ability of one-step self-etch adhesives on bonding to non-carious cervical sclerotic lesion. Forty-eight human maxillary premolars with and without natural non-carious cervical sclerotic lesions at buccal surfaces were used in this study. Artificial wedge-shaped lesions were prepared in sound premolars. All lesions were bonded with Bond Force (BF; pH=2.3) or G-Bond Plus (GBA; pH=1.5) according to the manufacturers' instructions. After water storage for 24 hours at 37°C, bonded specimens were subjected to microtensile bond test to measure bond strength to the gingival wall in each lesion. The µTBS of BF to the natural lesion was significantly lower than that of artificial lesion (p<0.05), while for GBA, there is no significant difference (p>0.05). There was no difference in µTBS to artificial lesion between these two adhesives, however in case of non-carious cervical sclerotic lesion, the µTBS of GBA was statistically higher than that of BF.