Direct orthodontic bonding to porcelain: an in vitro study.

The shear/peel and tensile/peel bond strengths of mesh-backed orthodontic brackets bonded to porcelain, using a highly filled composite and four different silane bonding agents were determined. Sites of failure were recorded for each method of testing. A method of debonding ane restoring the porcelain surface to its original state after debonding was also investigated. All silane bonding systems tested provided adequate bond strength for clinical use. Fusion produced significantly higher force values to failure in shear testing. There was no significant difference between the bond strengths obtained in tensile testing. Patterns of failure differed in each mode of testing, suggesting that a shear mode of debonding is more likely to cause porcelain fracture and that the possibility of porcelain fracture during function or debonding cannot be excluded. The use of a Lift-Off plier is recommended in debonding brackets from porcelain where a silane bonding agent has been used. Diamond polishing paste was better at restoring the procelain surface to its original appearance than Shofu polishing stones.     

In vitro orthodontic bracket bonding to porcelain

This in vitro study investigated the influence of using different combinations of bracket, adhesive, and light-curing source on the tensile bond strength to porcelain and on failure patterns at debonding. Tensile tests were performed using: one ceramic bracket versus one metal bracket, two orthodontic composites; type bisphenol A-glycidyldimethacrylate and urethane dimethacrylate (UDMA), and four light-curing units with the same range of emission spectrum but various light intensities: three light-emitting diode (LED) units and one halogen-based unit. One hundred and sixty porcelain samples were randomly divided into 16 equal groups. The porcelain surface was conditioned with 9 per cent hydrofluoric acid before silane application. The composite was photo-polymerized for 40 seconds. After storage in water at 37°C for 24 hours, the samples were subjected to tensile force until bond failure. Bond strength and bond failure mode were recorded; results were analysed (α = 0.05) using R language; linear model with constant variance for the bond strength and multinomial distribution for the failure mode. The bond strength in all groups was sufficient to withstand orthodontic treatment (>6 MPa). There was no statistical difference between the adhesives, but comparing bracket × light interaction, it was significantly higher with the ceramic bracket. No significant differences were seen between the metal bracket groups, but for the ceramic bracket, the results were significantly higher with the LED light. No fracture was observed in porcelain with the metal bracket but it occurred in 35 per cent of the ceramic bracket samples and the risk was higher when using UDMA composite and lower with LED high intensity light.     

Direct bonding of orthodontic brackets to porcelain veneer laminates

The forces required to debond orthodontic attachments from porcelain veneer laminates were studied in vitro. Brackets were bonded to 160 veneered bovine incisor teeth before the determination of the debond force. The independent variables studied were resin type, priming agent, porcelain surface preparation, and debonding time. The average debond forces were compared with those obtained by debonding brackets bonded to natural teeth by means of the acid-etch technique. The bond between the resin and the porcelain surface was found to be satisfactory for direct bonding of orthodontic attachments. Roughening the porcelain surface and using a silane primer required an average debond force comparable to that of the acid-etched enamel bond at 24 hours. However, it increased the risk for porcelain fracture during debonding. Roughened surfaces and surfaces with micro-fractures could be satisfactorily finished and polished with either a series of graded Ceramiste points or a diamond-impregnated polishing wheel followed by a diamond polishing paste.     

Orthodontic bonding to porcelain: a comparison of bonding systems

STATEMENT OF PROBLEM: Direct bonding of orthodontic brackets to porcelain surfaces has been plagued by failure. PURPOSE: The purpose of this study was to compare the bond strengths of several different bonding systems when bonding orthodontic brackets to porcelain-fused-to-metal surfaces. MATERIAL AND METHODS: Fifty natural glazed feldspathic porcelain-fused-to-noble metal disks 6 mm in diameter and 3 mm in height (1 mm metal and 2 mm porcelain) were fabricated and divided into 5 groups of 10. A different bonding system (GC America Fuji LC, American Ortho Spectrum, 3M Transbond, TP Orthodontics Python, and Kerr Herculite) was assigned to each group, and 50 identical orthodontic brackets were bonded (with the above mentioned systems) to each disk according to each manufacturer's instructions. Each system except TP Orthodontics Python conditioned with phosphoric acid (35% to 37.5%) and all systems were primed with silane before bonding. The specimens were subjected to gradual shear forces up to 123 N in a universal testing machine (Instron Corp, Canton, Mass.) until fracture. The shear bond strength of the bonding systems between the porcelain surface and the bracket was measured in megapascals (MPa). Failures were observed via a Zeiss optical microscope (10x); Tukey's HSD Test and analysis of variance were used to determine significance between the bonding systems at P<.05 level of significance. RESULTS: Failure of all of specimens was adhesive between the porcelain surface and the bonding agents. On the basis of a current literature review, bonding systems were categorized as clinically acceptable if they had a shear bond strength of 6 to 8 MPa. The 3M Transbond Bonding System, American Orthodontics Spectrum Bonding System, and GC America Fuji Ortho LC Bonding System performed within this clinically acceptable range (6 to 8 MPa), whereas Kerr Herculite Bonding System and TP Orthodontics Python Bonding System did not (2 to 4 MPa). The bond strengths of GC America Fuji Ortho LC, 3M Transbond, and American Orthodontics Spectrum were significantly greater (mean = 2.3 times) than TP Orthodontics Python or Kerr Herculite bonding systems. CONCLUSION: Within the limitations of this study, the results reaffirm the regimen of conditioning with phosphoric acid and priming with silane before bonding orthodontic brackets to feldspathic porcelain fused to noble metal. All products indicated for this purpose may not achieve satisfactory bond strengths; however, because they do not all include the critical steps of conditioning with phosphoric acid and priming with silane. The 3M Transbond Bonding System, American Orthodontics Spectrum Bonding System, and GC America Fuji Ortho LC Bonding System performed within the clinically acceptable range (6 to 8 MPa), whereas Kerr Herculite Bonding System and TP Orthodontics Python Bonding System did not (2 to 4 MPa).     

Orthodontic bonding using glass ionomer cement: an in vitro study.

The aim of this study was to investigate the in vitro 24-hour tensile/peel bond strength of glass ionomer cement (GIC) together with the amount of cement left attached to the enamel surface after bond failure. The effect of contamination with moisture during setting/hardening and changing the powder/liquid mixing ratio of the GIC was also studied. Five GIC's (Intact, Fuji II, Orthocem B, ChemFil II, and Ketac Fil[capsulated]) and one composite resin (Concise) were tested by bonding GAC eyelets, with a curved photo-etched base, to the buccal surface of human premolars. Bond strength testing was performed on an Instron 1185 testing machine and the amount of cement left attached to the enamel surface quantified using the ARI index. The tensile/peel bond strengths achieved with all the GIC's were significantly lower than the composite resin (P less than 0.0002). Increasing the powder/liquid ratio resulted, in general, in higher bond strengths, the increase being significant for Intact and Orthocem B (P less than 0.05). Protection from moisture did not significantly affect the bond strength with the exception of Fuji II, for which, there was a significant decrease when the material was mixed at the recommended powder/liquid ratio.     

Self-etching vs. traditional bonding systems in orthodontics: an in vitro study

The need for a bonding system that is consistently reliable, biocompatible, and most of all, easy to use and is unaffected by saliva contamination, has led to the development of products that did not require the initial step of etching the enamel surface. In these new systems elements of etching, priming and bonding are all in one component. The aim of this study was to compare the bonding strength of brackets with a traditional technique to the Prompt L-Pop (monocomponent adhesive) using the same composite resin. The results showed no statistical differences in detachment values of these two groups.     

The marginal fit of porcelain veneers on titanium copings: an in vitro study.

OBJECTIVES: To compare the cervical microleakage of titanium copings veneered with 3 porcelain-based materials with that of titanium copings veneered with 2 indirect polymeric materials. METHOD AND MATERIALS: Commercially pure, grade 2 titanium was veneered with 3 porcelain systems specially designed for fusing on titanium: Ti22 (Noritake), Triceram (Esprident), and Vitatitankeramik (Vita). Additionally, 2 polymeric materials were used for veneering titanium: Chromasit and Targis (Ivoclar). Four veneer crowns for each titanium-veneer combination were obtained. After storing the specimens in basic fuchsin, the microleakage between titanium and veneer in the cervical area was assessed by measuring the extent of dye penetration within the interface. ANOVA and post hoc statistics were used to analyze the data. RESULTS: Chromasit exhibited the highest mean microleakage score (3 +/- 0.816). The least mean microleakage at the interface was recorded for Ti22 porcelain (0 +/- 0.0), followed by Triceram (0.25 +/- 0.50), Vitatitankeramik (0.75 +/- 0.957), and Targis (1.5 +/- 1.732). Only the differences between each porcelain system and Chromasit were significant (P <.05). CONCLUSION: Within the limitations of this in vitro study, there was no significant microleakage between titanium copings and the porcelain veneers, regardless of the porcelain system. The microleakage between titanium and the polymeric materials depended on the veneering material. Leakage was significantly higher when Chromasit was used.     

Orthodontic bonding to porcelain: A systematic review

Objective:To use a systematic review to determine which materials and technique/protocol present the highest success rate in bonding brackets to porcelain surfaces.Materials and Methods:Different databases were searched without limitations up to July 2013. Additionally, the bibliographies of the finally selected articles were hand searched to identify any relevant publications that were not identified earlier. In vitro and in vivo articles were included.Results:No in vivo articles were found that fulfilled the inclusion criteria. A total of 45 in vitro articles met all inclusion criteria. They were published between 2000 to July 2013.Conclusions:The best protocol described in this review is the etching of 9.6% hydrofluoric acid for 1 minute, rinsed for 30 seconds, and then air-dried. The etching of hydrofluoric acid should be followed by an application of silane. Considering the harmful effects of etching with hydrofluoric acid, another appropriate suggestion is mechanical roughening with sandblasting followed by an application of silane.     

Use of a bonding agent to reduce sealant sensitivity to moisture contamination: an in vitro study.

Moisture contamination of etched enamel during application of sealant is the most frequently cited reason for sealant failure. In preliminary studies, a dentin bonding agent (Scotchbond Dual Cure, 3M, St. Paul, MN) has been shown to bond adequately to etched enamel after salivary contamination. This study investigated bond strength in vitro, when a bonding agent was used beneath sealants under varied conditions of contamination. Five hundred bovine incisor crowns were separated randomly into eight groups. The enamel samples, etched for 60 sec with a 37% phosphoric acid gel, were contaminated with: 1) fresh whole saliva, air dried, 2) fresh whole saliva, left wet, or 3) moisture from a humidity chamber. All contamination conditions were tested for sealant bond strength with and without the bonding agent as an intermediate layer under the sealant. As controls, both sealant and bonding agent under sealant also were applied to clean etched enamel. Bond strength was measured using a universal testing machine. Data were analyzed using a two-way ANOVA. Under conditions of humidity or intact saliva, sealant alone showed significant reduction in bond strength (P less than 0.001). Bonding agent under sealant on wet contamination yielded bond strengths equivalent to the bond strength obtained when sealant was bonded directly to clean, etched enamel. Bonding agent used without contamination yielded bond strengths significantly greater than the bond strength obtained when using sealant alone without contamination (P less than 0.001). When the saliva was air dried onto the surface, there was no significant difference in bond strengths whether or not a bonding agent was used under the sealant.     

A visible light-activated direct bonding material: an in vitro comparative study

This paper reports on the mechanical performance of a visible light cured orthodontic bonding agent. It is concluded that this type of material is as effective as other commercial adhesives and offers certain advantages in handling. Resistance to 4 kg of force in the shear/peel mode within the first 5 minutes of its application is expected from a clinically usable adhesive.     

自制镍铬烤瓷合金剪切结合强度的比较研究

目的探讨镍铬烤瓷合金中添加钛（Ti）、稀土金属以及不含铍（Be）对金瓷结合性能的影响。方法选用中国科学院金属研究所研制的镍铬烤瓷合金,按照是否含铍和稀土金属分为3个实验组（R1、R2、R3组）;以HI BONDNi-Cr烤瓷合金作为对照组（R4组）。对金瓷结合试件行剪切结合强度测试和金瓷界面的扫描电镜观察与能谱分析。结果R1、R2、R3、R4组剪切结合强度间差异无统计学意义（P＞0.05）。扫描电镜观察金瓷界面形貌可见,合金与瓷紧密接触,无裂缝。各组界面元素种类接近。结论自制镍铬烤瓷合金的金瓷结合良好,剪切结合强度可以达到临床应用的要求。在镍铬烤瓷合金中加入Ti和稀土金属且不含Be可作为临床使用的更好推荐。     

The role of diffusible ionic species in the bonding of polycarboxylate cements to dentine: an in vitro study.

Treatment of freshly-cut dentine with fluoride ions or high concentrations of metal ions produced changes ranging from mineralization of tubule contents to precipitation of adherent surface layers. Combinations of these treatments with application of fluoridated and non-fluoridated polycarboxylate cements and glass ionomer cements produced both increases and reductions in bond strength which are explained by ionic diffusion at the interface prior to setting.     

Investigation of a hydrophilic primer for orthodontic bonding: an in vitro study

A common reason for bond failure is moisture contamination. This study investigates the in vitro bond strength of brackets bonded using a new hydrophilic primer, designed to be insensitive to moisture, and compares it with a conventional primer. Using a standardized technique, the in vitro bond strength of brackets bonded with the hydrophilic primer was compared to identical brackets bonded with a conventional primer. Although designed to be moisture insensitive, the directions for use stipulate drying the teeth before bonding. Therefore, for the purposes of comparison with a conventional primer the experiment was conducted under dry conditions. The results were analysed using the Weibull distribution modelling. The median bond strength with the hydrophilic primer (6.43 MPa, 95 per cent C.I. 7.69-9.50) was significantly lower (P = 0.0001) than the conventional primer (8.71 MPa, 95 per cent C.I. 5.89-7.59). The Weibull distribution modelling showed that brackets bonded with the hydrophilic primer were 3.96 times more at risk of failure (95 per cent C.I.: 2.39-6.56; P <0.0001). The bond strength at which 5 per cent of the brackets failed was also lower for the hydrophilic primer. The bond strengths obtained with the hydrophilic primer were significantly lower than with the conventional primer. Although the median bond strength values were promising, the laboratory results for this particular hydrophilic primer were disappointing when using the Weibull analysis, where the whole distribution of bond strength is taken into account.     

The bonding of an adhesive resin cement to single and combined adherends encountered in resin-bonded bridge work: an in vitro study.

Although resin-bonded bridges should ideally be bonded to enamel, abutment teeth may present with dentine or restorations at the bonding sites. This study assessed the influence of bonding to such adherends on bridge retention by using tensile bond strength measurements as the criteria for judgement. An adhesive resin cement (Panavia Ex) was bonded to single adherends of enamel, dentine, composite resin, glass ionomer or amalgam, and to combined adherends of enamel/dentine or enamel/restorative material. The bond strength to enamel (28 MPa) was comparable with that to composite resin (25 MPa), but significantly higher than to dentine (8 MPa), amalgam (8 MPa) and glass ionomer (13 MPa). When the bonding area was half enamel and half restorative material, the bond strength was only equivalent to that obtained when the entire bonding area consisted of restorative material, the less favourable adherend. A similar trend was observed with specimens of enamel/dentine. This indicated that the magnitude of the bond between the resin cement and combined adherends was limited by the strength of the bond to the less favourable adherend. It appears that extending a bridge retainer to cover exposed dentine, a glass-ionomer filling or an amalgam filling, could adversely affect the bridge retention.