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Comparative evaluation of ceramic bracket base design
Volume 102 Number 5
a standard deviation of 2.13%. This ratio and formula can provide information for the ma.rillary and mandibular central and lateral incisors as to whether a tooth size discrepancy e.rists, where the discrepancy is located, and the extent of the discrepancy.
Radiofrequency glow discharge treatment for bonding orthodontic brackets. M. J. Wisniewski, Buffalo, New York: State University of New York at Buffalo, 1992
Currently, acid etching of the enamel surface of teeth is the widely accepted technique for bonding orthodontic brackets. Bond strength must be sufficient to withstand orthodontic and occlusal forces for the duration of therapy and then permit debonding with minimal trauma to the tooth and patient. Radiofrequency glow discharge treatment of inorganic materials has been used for treating metals, certain polymers, and implants. The purpose of this study was to determine whether radiofrequency glow discharge treatment of the enamel surface could provide adequate bond strength for orthodontic brackets. If the plasma applied to the enamel can clean the surface, increase wettability and expose a more reactive layer, the glow discharge treatment may provide an alternative to enamel etching as a pretreatment for bonding orthodontic brackets. Forty-five extracted human premolars were assigned to three groups: (I) pumice only, (2) pumice and 37% phosphoric acid etch for 60 seconds, and (3) pumice and glow discharge treatment. Orthodontic brackets were bonded with a no mix orthodontic adhesive. Shear bond strength was obtained for the three groups. A significant difference was found between the acid etched group, and the pumiced and glow discharged group. No difference in bond strength was found between the pumiced and the glow discharged groups.
Comparative evaluation of ceramic bracket base design. Joseph M. Bordeaux, Lincoln: University of Nebraska, 1991
Since the initial introduction of ceramic brackets, base designs have been modified to eliminate tooth damage during debonding. The purpose of this study was to compare shear and tensile bond strengths and fracture sites of four secondgeneration ceramic brackets: GAC Allure IV (A), TP Ceramaflex (C), Lancer Intrigue (1), and Unitek Transcend 2000 (T), and a foil-mesh base metal bracket (Unitek DynaBond II (D)). Twenty brackets of each type were bonded to 100 mandibular bovine incisor teeth with Concise bonding adhesive. The samples were thermocycled for 24 hours, and the brackets were debonded with an Instron universal testing machine. A Transcend debonding instrument was used for tensile debonding, whereas a chisel was used for shear debonding.
Reviews attd abstracts
489
An analysis of variance was performed with a 0.05 level of confidence. Mean shear strengths (kg/cm'-) necessary to debond were (C) 71.0, (A) 174.0, (D) 160.0, (I) 189.0, and (T) 228.0. Mean tensile strengths (kg/cm 2) were (C) 26.7, (A) 27.0, (D) 48.6, (I) 51.32, and (T) 56.5. Fracture sites examined with a light microscope showed no enamel damage with any of the ceramic brackets. (I) was the only bracket to fracture and had 30% bracket fracture in the tensile mode and 20% bracket fracture in the shear mode. The percentage of fractures at the adhesive-base interface for shear and tensile modes, respectively, were: (c) 100, 90; (A) 80, 100; (D) 90, 80; (1) 10, 60; (T) 60, 90. From the data in this study, it may be concluded that: (1) bracket base designs that allow for increased amounts of adhesive decreases bond strength; (2) plastic wafer bases attached to ceramic brackets have decreased bond strengths; (3) wing design on ceramic brackets is a factor in bracket failure when a tensile load is applied; and (4) a tensile force should be applied to remove ceramic brackets. This study was supported by a grant from the Unitek/3M Corporation.
Frictional properties of metal and ceramic brackets during simulated cuspid retraction. Hamid M. Omana, Lincohz: University of Nebraska, 1991 Ceramic brackets have gained wide popularity with both patients and orthodontists. However, very little has been done to document the frictional force effects of ceramic brackets. The purpose of this study was to test the hypothesis that ceramic brackets have higher frictional forces with sliding mechanics than do conventional metal brackets. The frictional properties of six different types of maxillary right 0.022-inch canine ceramic orthodontic brackets ("A" Company Starfire, Class One Contour Twin, GAC Allure IV, Ormco Lumina, Ortho Organizer Illusion, Unitek Transcend 2000) were co mpared with each other and with a similar metal bracket on straight sections of nickel-titanium and stainless steel wires. Each bracket was mounted in a simulated cuspid retraction device. Static frictional forces were measured with an Instron testing machine. A scanning electron microscope (SEM) was used to analyze the bracket slot surface characteristics of each bracket type. The results of the testing were analyzed statistically and revealed that increasing levels of bracket engagement (loads) resulted in a corresponding increase in friction. Ceramic brackets all exhibited significantly higher frictional forces when compared with the metal standard except for the injection molded Class One bracket. Wire type effects in this study were insignificant. The SEM analysis of the brackets demonstrated no correlation between the slot surface appearance and measured frictional forces. The sliding corners of the ceramic brackets may play a significant role in the frictional differences found among the various ceramic bracket types. This study was supported by a grant from Class One Orthodontics, Inc.
a standard deviation of 2.13%. This ratio and formula can provide information for the ma.rillary and mandibular central and lateral incisors as to whether a tooth size discrepancy e.rists, where the discrepancy is located, and the extent of the discrepancy.
Radiofrequency glow discharge treatment for bonding orthodontic brackets. M. J. Wisniewski, Buffalo, New York: State University of New York at Buffalo, 1992
Currently, acid etching of the enamel surface of teeth is the widely accepted technique for bonding orthodontic brackets. Bond strength must be sufficient to withstand orthodontic and occlusal forces for the duration of therapy and then permit debonding with minimal trauma to the tooth and patient. Radiofrequency glow discharge treatment of inorganic materials has been used for treating metals, certain polymers, and implants. The purpose of this study was to determine whether radiofrequency glow discharge treatment of the enamel surface could provide adequate bond strength for orthodontic brackets. If the plasma applied to the enamel can clean the surface, increase wettability and expose a more reactive layer, the glow discharge treatment may provide an alternative to enamel etching as a pretreatment for bonding orthodontic brackets. Forty-five extracted human premolars were assigned to three groups: (I) pumice only, (2) pumice and 37% phosphoric acid etch for 60 seconds, and (3) pumice and glow discharge treatment. Orthodontic brackets were bonded with a no mix orthodontic adhesive. Shear bond strength was obtained for the three groups. A significant difference was found between the acid etched group, and the pumiced and glow discharged group. No difference in bond strength was found between the pumiced and the glow discharged groups.
Comparative evaluation of ceramic bracket base design. Joseph M. Bordeaux, Lincoln: University of Nebraska, 1991
Since the initial introduction of ceramic brackets, base designs have been modified to eliminate tooth damage during debonding. The purpose of this study was to compare shear and tensile bond strengths and fracture sites of four secondgeneration ceramic brackets: GAC Allure IV (A), TP Ceramaflex (C), Lancer Intrigue (1), and Unitek Transcend 2000 (T), and a foil-mesh base metal bracket (Unitek DynaBond II (D)). Twenty brackets of each type were bonded to 100 mandibular bovine incisor teeth with Concise bonding adhesive. The samples were thermocycled for 24 hours, and the brackets were debonded with an Instron universal testing machine. A Transcend debonding instrument was used for tensile debonding, whereas a chisel was used for shear debonding.
Reviews attd abstracts
489
An analysis of variance was performed with a 0.05 level of confidence. Mean shear strengths (kg/cm'-) necessary to debond were (C) 71.0, (A) 174.0, (D) 160.0, (I) 189.0, and (T) 228.0. Mean tensile strengths (kg/cm 2) were (C) 26.7, (A) 27.0, (D) 48.6, (I) 51.32, and (T) 56.5. Fracture sites examined with a light microscope showed no enamel damage with any of the ceramic brackets. (I) was the only bracket to fracture and had 30% bracket fracture in the tensile mode and 20% bracket fracture in the shear mode. The percentage of fractures at the adhesive-base interface for shear and tensile modes, respectively, were: (c) 100, 90; (A) 80, 100; (D) 90, 80; (1) 10, 60; (T) 60, 90. From the data in this study, it may be concluded that: (1) bracket base designs that allow for increased amounts of adhesive decreases bond strength; (2) plastic wafer bases attached to ceramic brackets have decreased bond strengths; (3) wing design on ceramic brackets is a factor in bracket failure when a tensile load is applied; and (4) a tensile force should be applied to remove ceramic brackets. This study was supported by a grant from the Unitek/3M Corporation.
Frictional properties of metal and ceramic brackets during simulated cuspid retraction. Hamid M. Omana, Lincohz: University of Nebraska, 1991 Ceramic brackets have gained wide popularity with both patients and orthodontists. However, very little has been done to document the frictional force effects of ceramic brackets. The purpose of this study was to test the hypothesis that ceramic brackets have higher frictional forces with sliding mechanics than do conventional metal brackets. The frictional properties of six different types of maxillary right 0.022-inch canine ceramic orthodontic brackets ("A" Company Starfire, Class One Contour Twin, GAC Allure IV, Ormco Lumina, Ortho Organizer Illusion, Unitek Transcend 2000) were co mpared with each other and with a similar metal bracket on straight sections of nickel-titanium and stainless steel wires. Each bracket was mounted in a simulated cuspid retraction device. Static frictional forces were measured with an Instron testing machine. A scanning electron microscope (SEM) was used to analyze the bracket slot surface characteristics of each bracket type. The results of the testing were analyzed statistically and revealed that increasing levels of bracket engagement (loads) resulted in a corresponding increase in friction. Ceramic brackets all exhibited significantly higher frictional forces when compared with the metal standard except for the injection molded Class One bracket. Wire type effects in this study were insignificant. The SEM analysis of the brackets demonstrated no correlation between the slot surface appearance and measured frictional forces. The sliding corners of the ceramic brackets may play a significant role in the frictional differences found among the various ceramic bracket types. This study was supported by a grant from Class One Orthodontics, Inc.