Noncarious cervical sclerotic lesions (NCSL) are dental cervical lesions with noncarious sclerotic dentine (NCSD), which appears smooth, hard, and either light yellow or dark brown. Most NCSLs are wedge or dish shaped and commonly occur in canines and premolars, leading to dental hypersensitivity and aesthetic defect. The principal treatment is composite resin restoration; however, many clinical problems, such as retention loss, should not be ignored. NCSL's bonding interface includes NCSD and enamel, and interface pre-treatment can promote the bonding effect. This review summarizes current surface treatment methods and their influence on the bonding effectiveness of NCSL to provide guidance for clinical practice.
Acid Etching, Dental ; Composite Resins ; Dental Bonding ; Dental Restoration, Permanent ; Dentin-Bonding Agents ; Tooth Cervix

OBJECTIVE: To evaluate the microtensile bond strength of resin composite to glass ceramic, and the effect of surface treatment of resin composite and thermal cycling aging on the microtensile bond strength. METHODS: Rectangular blocks were made with dentin of extracted molars, resin composite or feldspathic glass ceramic respectively. The bonding surfaces of these rectangular blocks were sanded by 600-grit silicon carbide paper before luting. A self-etching resin cement was used as luting agent. The specimens were divided into groups according to the types of substrates of adhesion (dentin/glass ceramic or resin composite/glass ceramic), the way of surface treatments and whether thermal cycling aging ocurred. The dentin blocks were adhered to ceramic blocks as controls (group A1 and A2). The resin composite blocks were adhered to the ceramic blocks as experiment groups. The resin composite surfaces were treated by different ways before luting: no extra surface treatment (group B1 and B2), treated by ethyl methacrylate solution (group C1 and C2) or silane coupling agent (group D1 and D2), coarsened by 360-grit silicon carbide paper (group E1 and E2) or polished by 1 200-grit silicon carbide paper (group F1 and F2). After luting, the microtensile bond strength of the specimens were tested before (group A1-F1) or after (group A2-F2) thermal cycling aging. After microtensile bond strength test, the fracture bonding surfaces of the specimens were observed by a scanning electron microscopy to determine the type of bonding failure. The data were statistically analyzed using one-way analysis of variance. RESULTS: The microtensile bond strength of resin composite to glass ceramic with no extra treatment achieved high bond values before and after thermal cycling [B1 (30.02±3.85) MPa, B2 (26.83±3.14) MPa], which were statistically different from those of the control groups [A1 (20.55±4.51) MPa, A2 (12.94±0.69) MPa, P < 0.05]. The microtensile bond strength between the glass ceramic and resin composite did not increase after different surface treatments of resin composite. CONCLUSIONS The microtensile bond strength between resin composite and glass ceramic achieved as similar bond strength as that between dentin and glass ceramic and even better. Surface treatment of resin composite via methyl methacrylate solution, silane coupling agent, coarsening, or polishing did not increase the microtensile bond strength effectually.
Acid Etching, Dental ; Ceramics ; Composite Resins ; Dental Bonding ; Materials Testing ; Resin Cements ; Silanes ; Surface Properties ; Tensile Strength

OBJECTIVE: To compare the bonding durability of three different self-etch adhesives to primary enamel and dentin, and to investigate the effect of mild salivary contamination followed by air drying on the bonding durability. METHODS: Two hundred and forty enamel specimens were divided randomly into 16 groups (n=15/group)according to the adhesive system [self-etch adhesives: Clearfil SE Bond(SE), AdperTM Easy One (EO), Scotchbond Universal (SBU); total-etch adhesive: AdperTM Single Bond Plus(SL)], contamination status (non-contaminated vs. salivary-contaminated) and storage condition (stored in distilled water for 24 h vs. aging mode 5 000 thermal cycles in 5 ℃ and 55 ℃). Two hundred and forty dentin specimens were assigned in the same way. Shear bond strength for 12 specimens in each group were measured. The adhesive interface for the residual specimens in each group was observed by scanning electron microscopy(SEM). Data were analyzed by three-way analysis of variance and Tukey test(P < 0.05). RESULTS: For primary enamel, total-etch adhesive showed higher initial shear bond strength values (28.92±1.83) MPa and shear bond strength values (27.27±3.03) MPa after thermal cycles compared with the other groups, and the difference between the groups was statistically significant (P < 0.01). Shear bond strength values of EO decreased significantly in salivary-treated groups, regardless of storage conditions, and the difference was statistically significant (P < 0.01). For primary dentin, shear bond strength values of EO decreased significantly in salivary-treated groups after 24 h (P < 0.01). After 5 000 thermal cycles, total-etch adhesive showed significantly lower shear bond strength values (14.31±1.97) MPa compared with the other groups, and the difference between the groups was statistically significant (P < 0.01), and shear bond strength values of EO were significantly lower than those in SE and SBU groups (P < 0.01), regardless of contamination status. CONCLUSION Total-etch adhesive SL has better bonding durability to primary enamel. SE and SBU have better bonding durability to primary dentin and have a certain resistance to salivary contamination, while the bonding performance of EO is compromised greatly by mild salivary contamination followed by air drying.
Acid Etching, Dental ; Adhesives ; Dental Bonding ; Dentin ; Dentin-Bonding Agents ; Materials Testing ; Resin Cements ; Shear Strength ; Tooth, Deciduous

Tooth enamel is a complex mineralized tissue consisting of long and parallel apatite crystals configured into decussating enamel rods. In recent years, multiple approaches have been introduced to generate or regenerate this highly attractive biomaterial characterized by great mechanical strength paired with relative resilience and tissue compatibility. In the present review, we discuss five pathways toward enamel tissue engineering, (i) enamel synthesis using physico-chemical means, (ii) protein matrix-guided enamel crystal growth, (iii) enamel surface remineralization, (iv) cell-based enamel engineering, and (v) biological enamel regeneration based on de novo induction of tooth morphogenesis. So far, physical synthesis approaches using extreme environmental conditions such as pH, heat and pressure have resulted in the formation of enamel-like crystal assemblies. Biochemical methods relying on enamel proteins as templating matrices have aided the growth of elongated calcium phosphate crystals. To illustrate the validity of this biochemical approach we have successfully grown enamel-like apatite crystals organized into decussating enamel rods using an organic enamel protein matrix. Other studies reviewed here have employed amelogenin-derived peptides or self-assembling dendrimers to re-mineralize mineral-depleted white lesions on tooth surfaces. So far, cell-based enamel tissue engineering has been hampered by the limitations of presently existing ameloblast cell lines. Going forward, these limitations may be overcome by new cell culture technologies. Finally, whole-tooth regeneration through reactivation of the signaling pathways triggered during natural enamel development represents a biological avenue toward faithful enamel regeneration. In the present review we have summarized the state of the art in enamel tissue engineering and provided novel insights into future opportunities to regenerate this arguably most fascinating of all dental tissues.
Acid Etching, Dental ; Amelogenin ; Biomimetics ; trends ; Dental Enamel ; metabolism ; Dental Enamel Proteins ; Dentistry ; trends ; Tissue Engineering ; methods ; Tooth Remineralization

OBJECTIVE: To compare the dentin bonding strength evaluation between adult permanent teeth and youth permanent teeth after treatment for different durations by universal adhesives. METHODS: Ten adult permanent teeth and ten youth permanent teeth were selected for this study. The occlusal enamel layer was removed, and each tooth was cut into three pieces along the long axis. In total, 30 pieces of adult and youth teeth were prepared. The adult and youth teeth pieces were randomly divided into three groups and treated by universal adhesives for 10, 20, and 30 s. In this study, Scotchbond Universal (SBU) was selected as the universal adhesive. Slabs were treated by dual-cure resin cements. The specimens were tested by microshear strength test through a universal testing machine. Fracture modes were observed by a stereomicroscope. Other adult teeth and youth teeth were selected, two for each type, and treated and grouped in the same manner. Fluorescein (0.1% Rhodamine B) was dissolved in SBU adhesive, and the specimens were treated by the adhesives for 10, 20, and 30 s. Micromorphology of the resin protrusions on the adhesive surface was observed by laser confocal microscopy (CLSM). RESULTS: For the adult teeth, the highest micro-shear bonding strength was observed in the 20 and 30 s groups, and the values were higher than that of the 10 s group (P<0.05). For the youth teeth, the highest micro-shear bonding strength was observed in the 10 and 20 s groups, and the values were higher than that of the 30 s group (P<0.05). The micro-shear bonding strength in the 10 s youth teeth group was higher than that of the 10 s adult teeth (P<0.05) and was same as the adult teeth treated for 20 s (recommendation time of material instructions) (P>0.05). The main break patterns in different groups comprised adhesive failure fractures and several mixed failure fractures. No resin fracture mode was observed. CLSM revealed very few short resin protrusions in 10 s adult teeth group, whereas the number and length of resin protrusions significantly increased in the 20 s adult teeth group. The resin protrusions of the 30 s group were shorter than those of the 20 s adult teeth group. In different durations, the bonding interface in different youth teeth groups presented the same trend of change as the adult teeth. However, the number and length of resin protrusions in the 10 s group of youth teeth were all higher than those of the 10 s adult teeth group. CONCLUSIONS In clinical practice, the bonding agent treatment duration shall be shortened appropriately for youth permanent teeth, and that for adult permanent teeth shall not be shortened to less than 20 s. On the whole, the bond strength of youth permanent teeth can achieve no significant difference with the adult permanent teeth.
Acid Etching, Dental ; Adult ; Composite Resins ; Dental Bonding ; Dental Cements ; Dental Stress Analysis ; Dentin ; Dentin-Bonding Agents ; Humans ; Materials Testing ; Random Allocation ; Resin Cements

OBJECTIVE: To investigate influence of setting time on bond strength of different bioactive pulp capping materials with self-etch or etch-and-rinse adhesive. METHODS: Sixty specimens were prepared for each of the three tested capping materials, namely mineral trioxide aggregate (MTA), iRoot BP Plus (BP) and iRoot FS (FS). Specimens of each material were divided into three groups and bonded at three setting time points of the materials respectively: initial setting time (4 h for MTA, 2 h for BP and 20 min for FS), 24 h after application and 7 d after application. The specimen surfaces of each group were treated with self-etch mode or etch-and-rinse mode of one universal adhesive (Single Bond Universal, SBU) (n=10). The bonding area was restricted to a round area with 3 mm diameter, on which composite cylinders were build up with flowable composite and light cured completely. The shear bond strength was tested immediately with a shear strength tester and fracture mode was observed under stereo microscope and recorded. The mean shear bond strength for each group was analyzed with SPSS 19.0 software ANOVA method. The surface morphology of each material was observed after setting and acid treatment under scanning electron microscope. RESULTS: There was no significant difference among the three tested materials at either initial setting point or 7 d after application (P<0.05). The bond strength of MTA was significantly higher than those of BP and FS 24 h after application in both bonding modes (P<0.05). For all the three tested materials, shear bond strength was significantly higher for complete setting group than for initial setting group of the same material (P<0.05). Under scanning electron microscope, the characteristic crystal patterns could be observed on the three bioactive materials surfaces after complete setting, the size of which was bigger for MTA than for BP and FS. These features were lost to some extent after self-etch primer application or phosphoric acid etching. CONCLUSION Based on the present results, adequate bond strength can be obtained for FS at initial setting time, which is comparable with BP and MTA. This implies that clinically composite restoration can be placed over bioactive direct capping materials after shortened initial setting process in one visit.
Acid Etching, Dental ; Composite Resins ; Dental Bonding ; Dental Cements ; Dental Materials ; Dental Pulp Capping ; Dental Stress Analysis ; Dentin-Bonding Agents ; Materials Testing ; Resin Cements ; Shear Strength

Continuing advances in dentin bonding technology and adhesives revolutionized bonding of resin-based composite restorations. However, hybrid layers created by contemporary dentin adhesives present imperfect durability, and degradation of collagen matrix by endogenous enzymes is a significant factor causing destruction of hybrid layers. Bond durability can be improved by using enzyme inhibitors to prevent collagen degradation and to preserve integrity of collagen matrix. This review summarizes progress on matrix metalloproteinase inhibitors (including chlorhexidine, ethylenediaminetetraacetic acid, quaternary ammonium salt, tetracycline and its derivatives, hydroxamic acid inhibitors, bisphosphonate derivative, and cross-linking agents) and suggests prospects for these compounds.
Acid Etching, Dental ; Bisphenol A-Glycidyl Methacrylate ; Collagen ; Dental Bonding ; Dentin ; Dentin-Bonding Agents ; Humans ; Matrix Metalloproteinase 2 ; Matrix Metalloproteinase Inhibitors

OBJECTIVETo investigate the effect of epigallocatechin-3-gallate (EGCG) on biomodification of demineralized dentine substrate, in its permeability, hydrophobicity, and inhibition ability to collagen enzymatic degradation.

METHODSThe dentine substrates were treated with simulated pulpal pressure created by mixtures of 0.02%, 0.1% EGCG/bovine serum albumin (BSA) in acidic environment (pH4.4) for 48 h. A fluid-transport model was used to measure the fluid permeability through demineralized dentine substrate. Positive replicas of dentine substrate were fabricated before and after being subjected to acidic environment for scanning electron microscope (SEM) examination. The blank group contained no EGCG and the positive group were treated with Gluma desensitizer. Static contact angle measurements on demineralized dentin and 0.1% EGCG primed dentin were performed by contact angle analyzer. The priming time were 60 s, 120 s, 0.5 h, 1 h. Dentine specimens bonded with Adper single bond 2 were subjected to 100 mg/L collagenase and observed under SEM. Resin-bonded specimens (with 0.02%, 0.1%, 0.5% EGCG priming, or without EGCG priming) were created for micro-tensile bond strength evaluation (MTBS). Resin-bonded specimens after thermol cycling were created for MTBS evaluation.

RESULTSThe fluid permeability in the blank control group increased ([151.3±22.3]%), the fluid permeability in 0.1% EGCG/BSA group decreased ([23.7±6.3]%). Compared to the blank control group, the contact angle of 120 s, 0.5 h, 1 h groups increased by 31.0%, 53.5%, 57.8% in deep dentin and 37.4%, 59.3%, 62.4% in shallow dentin. The SEM examination showed that 0.1% and 0.5% EGCG priming for 120 s significantly increased dentin collagen's resistance to collagenase. The immediate MTBS of 0.1% and 0.5% EGCG groups were (29.4±4.8) and (19.8± 4.9) MPa. After thermol cycling, the MTBS of 0.1% and 0.5% EGCG groups were (19.9±5.1) and (15.3± 6.3) MPa.

CONCLUSIONSUnder acidic environment (pH4.4), the 0.1% EGCG can reduce dentine permeability under acidic environment. The 0.1% EGCG can increase hydrophobicity of dentin substrate, and strengthen dentin substrate's resistance to collagenase hydrolysis, thus increased the resin-dentin bonding durability.

Acid Etching, Dental ; Catechin ; analogs & derivatives ; pharmacology ; Collagen ; chemistry ; drug effects ; Collagenases ; pharmacology ; Composite Resins ; Dental Bonding ; Dental Cements ; Dental Pulp ; Dentin ; chemistry ; drug effects ; Dentin Permeability ; drug effects ; Dentin-Bonding Agents ; Glutaral ; pharmacology ; Hydrogen-Ion Concentration ; Hydrolysis ; Methacrylates ; pharmacology ; Microscopy, Electron, Scanning ; Pressure ; Resin Cements ; Serum Albumin, Bovine ; pharmacology ; Tensile Strength ; Time Factors

Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium (Ti), titanium-zirconium (TiZr) alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.
Acid Etching, Dental ; methods ; Alloys ; chemistry ; Bacterial Adhesion ; physiology ; Bacteriological Techniques ; Biofilms ; Cell Adhesion ; physiology ; Cell Culture Techniques ; Cell Line, Tumor ; Cell Movement ; physiology ; Ceramics ; chemistry ; Coculture Techniques ; Dental Alloys ; chemistry ; Dental Etching ; methods ; Dental Implants ; microbiology ; Dental Materials ; chemistry ; Dental Polishing ; methods ; Humans ; Osseointegration ; physiology ; Osteoblasts ; physiology ; Porphyromonas gingivalis ; physiology ; Prevotella intermedia ; physiology ; Surface Properties ; Titanium ; chemistry ; Yttrium ; chemistry ; Zirconium ; chemistry

OBJECTIVETo investigate the effectiveness of different surface treatments that could promote the bond strength of composite resin to commercially pure titanium.

METHODSThe 24 casting pure titanium specimen were randomly divided into four groups: Smooth group, rough group, acid etching smooth group, acid etching rough group. Each group had six specimens. In the different groups, the specimens were treated respectively under different surface treatments. The specimens of rough group was sandblasted, the acid etching smooth group was treated by acid etching, the acid etching rough group was treated by acid etching after sandblasting, the smooth group had no treatment. After surface treatment, the casting pure titanium specimens that were veneered by composite resin became titanium-composite resin specimen. Then the bond strengths were evaluated by universal testing machine and the surfaces were observed by scanning electron microscope including titanium surface appearance and titanium surface appearance of different groups after shear test.

RESULTSThe bond strengths of smooth group, rough group, acid etching smooth group, acid etching rough group were (3.08 +/- 0.45), (6.05 +/- 0.74), (6.27 +/- 0.80), (10.16 +/- 0.82) MPa, respectively. The statistical analysis showed that the bond strengths in rough group, acid etching smooth group, acid etching rough group were higher than in smooth group (P < 0.01). The highest bond strength was the acid etching rough group. There were no significant differences in the bond strength between rough group and acid etching smooth group (P > 0.05). There were some different titanium surface appearances in each group before and after testing.

CONCLUSIONTitanium surface treatment of sandblasting and etching can improve the bond strength between titanium and composite resin. The pre-treatment of sandblasting before etching is an effective modification method of titanium for bonding to composite resin.

Acid Etching, Dental ; Composite Resins ; Dental Bonding ; Dental Porcelain ; Materials Testing ; Shear Strength ; Surface Properties ; Titanium