The effect of porcelain surface conditioning on bonding orthodontic brackets

The purpose of this study was to evaluate the effects of a new self-etching primer/ adhesive used to enhance the shear strength of orthodontic brackets bonded to porcelain surfaces. Forty-five porcelain maxillary central incisor teeth were used in the study. The teeth were divided randomly into three groups: group I (control), the porcelain teeth were etched with 37% phosphoric acid followed by a sealant and the brackets were bonded with a composite adhesive; group II, the porcelain teeth were microetched and hydrofluoric acid and silane applied and metal brackets were then bonded with the composite adhesive; and group III, the porcelain teeth were etched with phosphoric acid and a self-etching primer/adhesive applied before bonding. Brackets precoated with the adhesive were used on all three groups of teeth. All teeth were stored for 24 hours at 37 degrees C before debonding. The results of the analysis of variance (F = 10.7) indicated that there was a significant difference (P = .001) between the three groups. The mean shear bond strengths of conventional bonding using a 37% phosphoric acid and sealant was 4.4 +/- 2.7 MPa, whereas that of microetching followed by the application of hydrofluoric acid and silane was 11.2 +/- 4.7 MPa, and for the new self-etching primer/adhesive it was 10.3 +/- 5.3 MPa. The last two groups had the highest bond strength values and were not significantly different from each other.     

Bonding to porcelain and gold

To test the effectiveness of bonding orthodontic attachments to porcelain, edgewise brackets were bonded to 160 lower incisor, porcelain denture teeth by means of two different resin systems and three different porcelain bonding agents. Bonding to porcelain was found to be not only effective, but the use of a porcelain primer before bonding resulted in shear strengths comparable to those achieved with conventional acid-etch enamel bonding when the same resin was used. Roughening the porcelain surface and bonding with a heavily filled resin without a porcelain primer provided shear strengths (30.6 Ibs) comparable to conventional acid-etch enamel bonding with a lightly filled resin (28.8 Ibs). Roughening the porcelain surface before bonding, adding porcelain primers, and using highly filled resins all added significantly to bond strength, but caused a progressively greater risk of porcelain fracture during debonding. One of three methods to polish porcelain completely restored a roughened porcelain surface to its former appearance. The porcelain bonding primers failed to provide a significant increase in bond strength when bonding to gold. However, a roughened gold surface bonded with a heavily filled resin provided shear strengths (27.3 Ibs) comparable to conventional acid-etch enamel bonding by means of a lightly filled resin (28.8 Ibs). The use of a highly filled resin on an intact, glazed porcelain surface without using a porcelain primer may provide sufficient bond strength clinically. If more bond strength is needed, the use of Reliance porcelain primer on an intact glaze is preferable to Ormco porcelain primer or Fusion. Still greater bond strength can be developed by roughening the porcelain surface before application of a primer and use of a highly filled resin. The potential for porcelain fracture in debonding, however, is much increased and it is questionable whether bond strengths of this magnitude are required clinically.     

Assessing the performance of a methyl methacrylate-based resin cement with self-etching primer for bonding orthodontic brackets

Questions over the usefulness of a self-etching primer with resin adhesive in the bonding of orthodontic brackets remain unsolved. The purpose of this study was to determine the effects of using Multibond, a new methyl methacrylate (MMA)-based resin cement with self-etching primer, on the shear bond strength of orthodontic brackets compared with Superbond C&B, which is a well-known MMA-based resin cement containing phosphoric acid etching. Metal or plastic brackets were bonded to etched or self-etching primed bovine teeth using Superbond C&B or Multibond. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours. Data were analyzed by two-way analysis of variance and Scheffe's test. The surface appearances of the teeth after phosphoric acid etching or self-etching priming were observed by field-emission scanning electron microscopy (FE-SEM). Metal brackets bonded with Multibond had a significantly lower shear bond strength than metal brackets bonded with Superbond C&B. No significant differences in shear bond strength were observed between Multibond and Superbond C&B when plastic brackets were bonded to the enamel. The shear bond strength of metal brackets bonded with Multibond was comparable with that of plastic brackets bonded with Superbond C&B. Adhesive remnant index score showed a tendency of more residual resin cement remaining on the teeth when metal brackets were bonded with Multibond. FE-SEM observation revealed less dissolution of the enamel surface resulting from treatment with Multibond self-etching primer as compared with phosphoric acid. Thus, the Multibond system may be a candidate for bonding orthodontic brackets with the advantage of minimizing enamel loss.     

Factors affecting the shear bond strength of orthodontic brackets to porcelain

The aim of this investigation was to establish a regime for orthodontic bonding to feldspathic porcelain, which ensures adequate bond strength (6-8 MPa) with minimal damage on debond and consisted of an ex vivo investigation measuring the effects of porcelain surface preparation and thermocycling on shear bond strength of orthodontic brackets. One-hundred-and-twenty feldspathic porcelain bonded crown surfaces were divided into 12 equally-sized groups to assess the effects of: (1) glaze removal, (2) application of hydrofluoric acid, phosphoric acid, or omission of acid treatment, and (3) silane priming upon the bond strength of premolar brackets bonded with Right-on (TM) composite resin adhesive. Specimens were subjected to thermocycling and then to shear debonding forces on an Instron machine. Removal of the porcelain glaze, or use of hydrofluoric acid, prior to bonding were found to be unnecessary to secure the target bond strength. Hydrofluoric acid application was associated with increased porcelain surface damage. Thermocycling caused a significant reduction in shear bond strength to porcelain (P < 0*001). The best regime for orthodontic bonding to feldspathic porcelain was to apply phosphoric acid for 60 seconds, and prime with silane prior to bonding. Usually the porcelain surfaces could be repolished. Refereed Paper     

The B.S.S.O. M. Orth. Prize of the Royal College of Surgeons of England 1996.

Abstract

The aim of this investigation was to establish a regime for orthodontic bonding to feldspathic porcelain, which ensures adequate bond strength (6–8 MPa) with minimal damage on debond and consisted of an ex vivo investigation measuring the effects of porcelain surface preparation and thermocycling on shear bond strength of orthodontic brackets.

One-hundred-and-twenty feldspathic porcelain bonded crown surfaces were divided into 12 equally-sized groups to assess the effects of: (1) glaze removal, (2) application of hydrofluoric acid, phosphoric acid, or omission of acid treatment, and (3) silane priming upon the bond strength of premolar brackets bonded with Right-on ? composite resin adhesive. Specimens were subjected to thermocycling and then to shear debonding forces on an Instron machine.

Removal of the porcelain glaze, or use of hydrofluoric acid, prior to bonding were found to be unnecessary to secure the target bond strength. Hydrofluoric acid application was associated with increased porcelain surface damage. Thermocycling caused a significant reduction in shear bond strength to porcelain (P < 0?001). The best regime for orthodontic bonding to feldspathic porcelain was to apply phosphoric acid for 60 seconds, and prime with silane prior to bonding. Usually the porcelain surfaces could be repolished.

Refereed Paper     

The effect of saliva on shear bond strengths of hydrophilic bonding systems.

Failure of orthodontic bonded attachments and brackets is mostly attributed to contamination of the enamel surface. To overcome this problem, materials have been developed that purportedly overcome the moisture and contaminants present in the oral environment. This study compared the shear bond strengths of 2 lightcured hydrophilic bonding systems, Transbond XT with MIP (3M/Unitek, Monrovia, Calif) and Assure (Reliance Orthodontics, Itasca, Ill) with a hydrophobic bonding system, Transbond XT with XT primer (3M/Unitek). Comparison tests were conducted under 4 enamel surface conditions: (1) etched and dried; (2) etched and moistened with artificial saliva; (3) etched, primed, and moistened with artificial saliva; and (4) etched, primed, moistened with artificial saliva, and reprimed. In addition, an adhesive remnant index score was used to determine the amount of adhesive remaining on the tooth. Stainless steel brackets with mesh-backed pads (n = 144) were bonded to bovine teeth. Bond strength was then tested in shear using an Instron mechanical testing instrument. There were significant differences in the bond strengths among the products (P <.05), within surface treatments (P <.05), and among the different bonding materials in combination with various surface treatments (P <.05). Treatments 1 and 4 showed the highest mean bond strengths adhesive remnant index scores, whereas treatments 2 and 3 showed the lowest mean bond strengths and scores.     

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.     

Shear bond strength of silicoated bonded orthodontic attachments

The shear bond strength of bonded orthodontic attachments, coated with a silicon oxide layer to enhance adhesion, was tested and compared to that of untreated attachments. Twenty buttons for direct bonding (test group) were "silicoated" and bonded to surgically removed, unerupted human third molars, using "Right-On" adhesive. The control group consisted of 20 similar teeth to which untreated buttons were bonded. Half of the specimens in each group were then thermocycled to stress the bonds. Shear strength was tested with the use of the Instron Universal testing machine. The mean shear bond strength of the silicoated attachments was found to be higher than that of the untreated attachments. This was a highly significant finding (p less than 0.005). The bond strength after thermocycling decreased in both the test and control groups, although this decrease was only significant at the level p less than 0.01. The results obtained from this study indicate that silicoating of orthodontic attachments prior to bonding significantly increases their shear bond strength to dental enamel.     

瓷面处理对金属托槽与瓷面粘接性能的影响

目的　研究瓷表面不同处理方法对金属托槽与瓷修复体的粘接强度及去粘接后瓷面完整性的影响。方 法　根据使用粘接剂和表面处理方法的不同,将80个瓷面随机分为8组,每组10个瓷面。分别用京津釉质粘接剂 和光固化复合树脂粘接,表面处理分别行37%磷酸酸蚀、9·6%氢氟酸酸蚀、打磨去釉、瓷面涂硅烷偶联剂4种表面 处理法。试件粘接托槽后经37℃恒温水浴24 h后测定抗剪切强度,记录去粘接后的瓷面破裂情况。对磷酸酸蚀, 氢氟酸酸蚀、打磨去釉的瓷面进行扫描电镜观察。结果　采用氢氟酸酸蚀、打磨去釉、硅烷偶联剂组的粘接抗剪切 强度明显高于磷酸酸蚀组(P<0·01)。打磨去釉后用光固化复合树脂粘接及氢氟酸酸蚀或瓷表面涂硅烷处理后使 用任意一种粘接材料粘接均取得有效的粘接强度。各组去粘接后的瓷破裂率无显著性差异(P>0·05)。结论　氢 氟酸酸蚀、打磨去釉、瓷面涂硅烷偶联剂均可以明显增加金属托槽与瓷面之间的粘接抗剪切强度。瓷面涂硅烷偶 联剂是金属托槽与瓷面粘接时良好的表面处理剂。     

Glass ionomer cements used as bonding materials for metal orthodontic brackets. An in vitro study

The forces required to debond orthodontic brackets on human teeth were studied in vitro. The brackets were bonded with different glass ionomer cements (GICs), and a composite resin (Concise). The shear force required to remove the brackets was recorded at different time intervals after bonding. The bond strength was considerably lower for the GICs compared with brackets bonded with the composite resin, at all time intervals that were studied. Moreover, the bond strength increased more slowly for the GICs compared with the resin. Different GICs displayed a varying setting time. The bonding strength of GICs increased more than 50 per cent between 10 and 20 minutes setting time.     

The effect of repeated bonding on the shear bond strength of different orthodontic adhesives.

One problem clinicians face during treatment is bracket failure. In a busy orthodontic practice, a significant number of teeth will need to be rebonded. The purpose of this study was to evaluate the effect of repeated bonding with 2 different adhesives, a composite and a cyanoacrylate, on the shear bond strength of orthodontic brackets. Thirty-one freshly extracted human molars were collected. Brackets were bonded with 1 of the orthodontic adhesives according to the manufacturer's instructions. In group I, the teeth were etched with 37% phosphoric acid, a sealant was applied, and the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and light cured for 20 seconds. In group II, the teeth were etched with 35% phosphoric acid, and the brackets were bonded with SmartBond (Gestenco International, G?thenburg, Sweden). In each group, the teeth were bonded and debonded 3 times with the same adhesive. At each sequence, the brackets were removed within 30 minutes after bonding to simulate the clinical condition at which a newly bonded bracket is tied to the archwire. Student t tests and the analysis of variance repeated measure were used to compare the shear bond strength between adhesives and within each adhesive at different debonding sequences. The results indicated that, at the first debonding sequence, the 2 adhesives did not have significantly different shear bond strengths. Between debonding sequence 1 and 2, there was a significant (P 相似文献   

An investigation into the bonding of orthodontic attachments to porcelain

This study assessed bonding of orthodontic brackets to porcelain teeth using two different surface preparation techniques and comparing two bonding systems, Fuji Ortho L.C. and Transbond. Four groups of 20 porcelain premolar teeth were bonded with metal orthodontic brackets (0.022 inch Minitwin, 3M Unitek) according to the following protocol: Transbond with a phosphoric acid etch (group 1), Transbond with a hydrofluoric acid etch (group 2), Fuji Ortho L.C. with a hydrofluoric acid etch (group 3), and Fuji Ortho L.C. with a phosphoric acid etch (group 4). All groups were bonded with a silane coupling agent. The teeth were debonded with an Instron universal testing machine. Bond strength, site of bond failure and adhesive remnant index (ARI) were recorded for each group. Differences between groups were analysed statistically. The composite resin groups (groups 1 and 2) had the highest mean bond strength values at 7.9 and 9.7 MPa, respectively. The resin-modified glass ionomer cement groups (RMGIC; groups 3 and 4) had the lowest mean bond strength values at 6.3 and 1.8 MPa, respectively. The mean bond strength of group 3 was significantly lower than all other groups (P < 0.0001). The Fuji groups had also significantly (P < 0.001) lower ARI scores than the composite groups (groups 1 and 2). Most samples experienced porcelain surface damage, except group 4. In conclusion, the highest bond strength levels were achieved with a conventional composite resin cement (groups 1 and 2). No significant differences in bond strength were found between the hydrofluoric and phosphoric acid etch technique.     

Indirect versus direct bonding: bond strength and failure location

Bond strengths and failure locations in direct and indirect bonding of orthodontic brackets with foil-mesh bonding pads were compared in an in vitro study that used extracted human premolars. The direct technique comprised bonding the attachments directly to the premolars with composite resin. The indirect technique comprised bonding the attachments to die-stone models of the teeth with composite resin, making silicone positioners to transfer the attachments from the models to the teeth, and bonding to the teeth with the use of two-part unfilled resin. One part of the unfilled resin was applied to the teeth and the other part to the composite resin that was already bonded to the attachments. Placing the positioners on the teeth brought the two parts together to initiate setting. Inspection after bonding disclosed marginal voids in two thirds of the indirect bonds. Of these, two thirds were then sealed with unfilled resin and one third were left defective. There were no significant differences in strength among direct, void-free indirect, and sealed indirect bonds. Indirect bonds with voids were only half as strong. This seems to indicate that sealing around brackets immediately after positioner removal might be a worthwhile clinical routine. Forty-four percent of the direct bonds fractured predominantly at the bracket-adhesive interface, whereas 72% of the indirect bonds failed mainly at the enamel-resin interface. Grouping the data according to failure location showed no difference in bond strength between those that failed at the enamel and those that failed at the bonding pad. Thus the indirect bonding promised similar bond strength and easier debonding because less resin was left on the teeth.     

Effects of potassium nitrate and oxalate desensitizer agents on shear bond strengths of orthodontic brackets

OBJECTIVE: To evaluate the effects of potassium nitrate and oxalate desensitizer agents on shear bond strengths of orthodontic brackets. MATERIALS AND METHODS: Forty-five extracted human premolar teeth were randomly assigned to three groups of 15 each. UltraEZ potassium nitrate desensitizer was applied on teeth in the first group, while BisBlock oxalate desensitizer was applied on teeth in the second group. The third group served as a control. Orthodontic brackets were bonded with a light cure composite resin and cured with a halogen light. After bonding, the shear bond strength of the brackets was tested with a universal testing machine. RESULTS: The highest shear bond strengths were measured in Group III. The shear bond strength in Groups I and II was significantly lower than in Group III (P < .001). Significant difference was also found between Group I and Group II (P < .01). CONCLUSIONS: Orthodontic brackets bonded to enamel treated with potassium nitrate and oxalate desensitizers showed significantly lower bond strengths than did brackets bonded to untreated enamel.     

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.     

Bonding brackets to porcelain--in vitro study

The aim of this research was to verify, in vitro, the effect of various porcelain surface treatment on the shear strength of orthodontic brackets bonded to porcelain and the mode of fracture after debonding. Eighty-eight samples of metallic supported feldspathic porcelain were randomly divided into four groups according to their surface preparation as follows: the porcelain was maintained intact (GI), roughened with a diamond bur (GII), etched with 10% hydrofluoric acid (GIII), or sandblasted with aluminum oxide (GIV). The specimens were treated with silane (Scotchprime) and brackets were bonded with Concise. Each sample was subjected to a shear load at a crosshead speed of 1 mm/min and a recording was made at the point of failure. Bond strengths, adequate to withstand the application of orthodontic forces, were achieved in all groups. The Kruskal-Wallis statistical test showed no significant differences in bond strength between the groups (p > 0.05). However, many more porcelain fractures occurred on deglazed porcelain. This study indicates that with the appropriate material selection, the silane/composite procedure alone may be adequate for bonding.     

Shear bond strength comparison between direct and indirect bonded orthodontic brackets.

The purpose of this study was to compare the shear bond strength of orthodontic brackets bonded to teeth with either an indirect bonding technique and a new adhesive resin or a direct bonding technique and a light-activated adhesive. Fifty-four extracted premolars were mounted in acrylic blocks and randomly divided into 2 groups (n = 27). In one group, orthodontic brackets were bonded to premolars with an indirect bonding adhesive system; in the other, brackets were bonded with the direct method. Seventy-two hours later, the brackets were placed in a testing machine and subjected to a shear force with a crosshead speed of 1 mm/minute. The mean shear bond strengths for the indirect and direct groups were 11.2 and 10.9 MPa, respectively, both exceeding the minimum shear bond strength range of 5.9 to 7.8 MPa often cited in the literature for clinical success. Data were analyzed with Student t tests. No significant difference in shear bond strength between the 2 groups was detected (P =.76). Resin remnants on orthodontic bracket pads were observed with a dissecting microscope at 30x magnification and scored with a modified adhesive remnant index. There was no significant difference between groups (P >.05). There was also no correlation between shear bond strength and the percentage of adhesive resin remnants left on the orthodontic bracket. Under the conditions of this study, no evidence suggests a difference in shear bond strength of orthodontic brackets bonded to tooth enamel, whether they are bonded with the direct or indirect technique.     

Shear bond strength of a new high fluoride release glass ionomer adhesive

OBJECTIVE: To determine the shear bond strength of a new resin glass ionomer adhesive with higher fluoride release properties when bonding orthodontic brackets. MATERIALS AND METHODS: Sixty freshly extracted human molars were collected and stored in a solution of 0.1% (weight/volume) thymol. The teeth were cleaned and polished. The teeth were randomly separated into three groups according to the enamel conditioner/etchant and adhesive used. Group I: 20 teeth conditioned with 10% polyacrylic acid and brackets bonded with the new glass ionomer adhesive. Group II: 20 teeth conditioned with 37% phosphoric acid and brackets bonded with the new glass ionomer adhesive. Group III (control): 20 teeth etched with 37% phosphoric acid and brackets bonded with a composite adhesive. RESULTS: The results of the analysis of variance comparing the three experimental groups (F = 10.294) indicated the presence of significant differences between the three groups (P = .0001). The shear bond strengths were significantly lower in the two groups bonded with the new glass ionomer adhesive whether conditioned with polyacrylic acid ( x = 3.2 +/- 1.8 MPa) or phosphoric acid (x = 2.3 +/- 1.1 MPa), while the mean shear bond strength of the composite adhesive was 5.2 +/- 2.9 MPa. CONCLUSIONS: Although the increased fluoride release from the new glass ionomer has the potential of decreasing decalcification around orthodontic brackets, the shear bond strength of the material is relatively low.     

Office reconditioning of stainless steel orthodontic attachments

An investigation was conducted to determine a simple, effective method for reconditioning stainless steel orthodontic attachments in the orthodontic office. In total, 100 new brackets were bonded to premolar teeth, then debonded and the bond strength recorded as a control for the reconditioning process. The debonded brackets were divided into six groups and each group reconditioned using different techniques as follows: attachments in four groups were flamed and then either (1) sandblasted, (2) ultrasonically cleaned, (3) ultrasonically cleaned followed by silane treatment, (4) rebonded without further treatment. Of the two remaining groups, one was sandblasted, while the brackets in the other were roughened with a greenstone. The brackets were rebonded to the premolar teeth after the enamel surfaces had been re-prepared, and their bond strengths measured.The results indicated that sandblasting was the most effective in removing composite without a significant change in bond strength compared with new attachments. Silane application did not improve the bond strength values of flamed and ultrasonically cleaned brackets. Attachments that had only been flamed had the lowest bond strength, followed by those that had been roughened with a greenstone.     

Direct bonding to porcelain: an in vitro study.

Three different force strengths were tested to investigate the effect of Fusion in direct bonding of brackets to porcelain. The resistance values of shear, tensile, and rotation strength forces are acceptable in the range of forces commonly used in orthodontics. The mean shear strength had greater resistance values to breaking than two other groups. The roughness of glazed porcelain and the fit of brackets to contoured porcelain teeth seems to be of great importance in the bonding effects. The role of Fusion in direct bonding is comparable to that of other sealants which are commonly being used in direct-bonding systems. It is claimed that Fusion creates a chemical bond with acrylic or composite resins to porcelain. The technique could be summarized as follows: (1) Glaze is removed in the area which is supposed to be bonded directly. (2) Fusion is applied over the roughened surface. (3) Acrylic or composite resin is mixed and applied on the mesh part of brackets. (4) The bracket is pressed against the porcelain teeth by moderate pressure until final polymerization.