IU Indianapolis ScholarWorks :: Browsing by Subject "Bonding, Dental"

Browsing by Subject "Bonding, Dental"

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A Study of the Effectiveness of Topical Fluoride Treatment Following the Removal of Direct Bonded Brackets
(1976) Short, Steven T.; Garner, LaForrest D.; Kasle, Myron J.; Cunningham, Donald M.; Shanks, James C., Jr.; Barton, Paul; Phillips, Ralph W.
In this investigation an attempt was made to determine what effect direct bonded attachments have on the posttreatment uptake of topically applied fluoride. Thirty-two freshly extracted mandibular central and lateral incisors were used. The teeth were cleaned, labeled and an adhesive tape window applied to the crown exposing a circular area one quarter inch in diameter on the labial surface. An initial enamel biopsy was performed to determine the fluoride content of the labial surface. Fifty percent phosphoric acid was applied for one minute to condition the teeth for bonding. A polycarbonate orthodontic bracket was then bonded with Sevriton resin and each tooth was stored for one week in water. After storage, the brackets were then removed and residual resin was cleaned off with a dental scaler. Half of the teeth were pumiced with flour of pumice for ten seconds. The teeth were observed microscopically to determine the condition of the labial surface. A 2% solution of sodium fluoride was applied to the teeth for eight minutes and the samples were then individually stored in water for one week. An enamel biopsy was performed and analyzed for fluoride, calcium, and phosphorus. A great deal of fluoride was taken up by the enamel surface on all the specimens. It was found that pumicing the teeth prior to the application of topical fluoride results in a significantly greater uptake of fluoride by the enamel surface. The results of this investigation indicate that a pumice wash following bracket removal facilitates a greater and more uniform uptake of topically applied fluoride on the surface of the teeth.
Clinical Evaluation of Glass Ionomer Cement as an Adhesive for the Bonding of Orthodontic Brackets
(1988) Miller, James R.; Garner, LaForrest D.; Moore, B. Keith; Shanks, James C., Jr.; Barton, Paul; Potter, Rosario H.
Glass ionomer cement has been shown in previous studies to retard decalcification and caries formation. This cement would be valuable in orthodontics if it proved to have adequate adhesive properties. Therefore, this study was designed to determine if there is a significant difference in the failure rate of brackets attached to teeth using a glass ionomer cement, Ketac-fil, and the failure rate of brackets attached to teeth using a conventional orthodontic adhesive system, Rely-a-bond. Six patients in the Department of Orthodontics at Indiana University School of Dentistry participated in this study. Each patient had 16 to 20 teeth available for bracketing. Direct-bond orthodontic brackets were attached to one-half of each participant's available teeth using Ketac-fil. Rely-a-bond was used to bond brackets to the remaining half of the teeth. Fifty-three brackets were placed with Ketac-fil, and 53 with Rely-a-bond. This study lasted a minimum of ten weeks for each patient. The following observations were made: 1) The failure rates for brackets attached with Ketac-fil and those attached with Rely-a-bond. 2) The type of bracket failure for brackets bonded with Ketac-fil. 3) Pre-study and post-study decalcification patterns of teeth with brackets attached with Ketac-fil. The bracket failure rate was 3.77% for the Ketac-fil group and 5.66% for the Rely-a-bond group. There was no significant difference between the failure rates of these two groups at the alpha = 0.05 level when tested with the Fisher Exact Probability Test. Of the two brackets that failed in the Ketac-fil group, only one was available for examination and it demonstrated a definite adhesive type of bracket failure. With respect to decalcification patterns, no obvious change in pattern occurred for teeth in the Ketac-fil group. There was no statistical difference between the failure rates of brackets attached with Ketac-fil and those attached with Rely-a-bond. Previous studies have shown that glass ionomer cements release fluoride and that this may retard decalcification and caries formation. Decalcification and caries formation around the margins of orthodontic brackets have been identified as potential risks of orthodontic treatment. Thus, the use of a glass ionomer cement as a bonding agent in orthodontics might reduce these potential risks without compromising the attachment of the brackets to teeth. This study provides the basis for more extensive clinical trials of glass ionomer cements as bonding agents for direct-bond orthodontic brackets.
Effects of sealant conditioners on occlusal surface bacteria: a clinical study
(1976) Johns, Michael R. (Michael Reed), 1946-
This clinical study evaluated the effects of conditioning agents for pit and fissure sealants on the bacteria present in occlusal grooves and fissures in permanent molars. The conditioning agents, 50 percent phosphoric acid and 50 percent phosphoric acid attenuated with 7 percent zinc oxide, with distilled sterile water being used as a control, were compared for their ability to kill bacteria in carious occlusal lesions. Eighty-six teeth from children eight to twelve years of age were conditioned with one of the randomly assigned agents using a blind method to prevent bias. The teeth were then cultured with a method that measured results as to growth or no growth after incubation. The culturing was done at both the occlusal surface and the depth of the lesion. A chi square test demonstrated that there were no significant differences between the conditioners on either the occlusal or depth of the lesion cultures (x2 = .31, df = 2, a = .05). The two conditioners did not totally kill the bacteria in occlusal lesions often enough to justify their use as bactericidal agents before sealants are applied.
An Evaluation of the Bond Strength and Failure Site of Composite Resin and Glass Ionomer in Identical Orthodontic Direct Bonding Systems
(1989) Fryar, Brian C.; Garner, LaForrest D.; Moore, B. Keith; Newton, Carl W.; Shanks, James C.; Koerber, Leonard G.
Glass ionomers offer several advantages for orthodontic cementation of brackets including no etching of enamel, fluoride release, and ease of debonding. This study compared in vitro bond strengths of glass ionomers with a composite resin. Two luting glass ionomers, (Ketaccem and Fuji I), two restorative ionomers, (Ketac-fil and Fuji II), and an orthobonding resin, (System 1 +), were used. Extracted human maxillary premolars were selected for a sample of 22 per cement. The teeth were pumiced prior to bonding. Ormco minimesh bicuspid brackets were bonded following manufacturer's directions. Only the teeth bonded with resin cement were etched. After bonding the teeth were stored in water at 37 C for 7 days and thermocycled 2500 times through a 40° c differential. Tensile bond strengths were measured at a crosshead speed of 0.5mm/min. Debonded specimens were examined to record failure modes. System 1+ had a bond strength of 103 +/- 21 kg/cm2 with 80% cohesive failure in the cement. Ketac-fil, Ketaccem and Fuji II were not significantly different and had strengths of 32.6 +/- 6.4, 31.9 +/- 7.1 and 33.7 +/- 8.5 respectively. Failure was 93% cohesive in the cements. Fuji I had a strength of 26. 6 +/- 4. 7 with 89% cohesive failure and was significantly weaker than the others. Although the strengths of the glass ionomers studied were substantially lower than the resin, they failed consistently in cohesive fracture through the cement with relatively small deviations. Since the minimum bond strength required for clinical success is not known, only a controlled clinical study can determine the ultimate effectiveness of glass ionomers as orthodontic bonding adhesives.
A Study of Microleakage in Orthodontic Direct Bonding Adhesive Systems
(1976-06) Ackerman, Gerald Lee; Garner, LaForrest D.; Shanks, James C., Jr.; Barton, Paul; Dickey, David M.; Swartz, Marjorie L.
If orthodontic direct bonding adhesives are to be successful, they must withstand the destructive influences of the oral environment and form a durable bond with enamel. Investigators have noted that moisture may be the greatest deterrent to an adhesive bond and water may have the ability to penetrate the adhesive-enamel interface, destroying this bond. An in vitro investigation was undertaken to determine whether moisture and other oral debris can penetrate this adhesive-enamel interface. Four commercially available orthodontic direct bonding systems were tested for microleakage using radioisotope45 calcium chloride (45Ca). Adhesives tested included Orthomite IIS, Directon, Unitek, and Genie. Polycarbonate brackets were bonded to freshly extracted human premolar teeth using the respective adhesive systems. Specimens were stored in 37.5°c water baths for periods of thirty days and ninety days before being tested. All specimens were thermal cycled 2500 cycles to provide a more heroic test. The thermal stressing was carried out at 15°c and 45°c with a 30 second dwell at each temperature. A total of eighty specimens were evaluated. The results of this study suggest that two of the orthodontic adhesives evaluated are susceptible to amounts of microleakage. Storage in water did affect the rate of leakage among the specimens. Generally, more specimens in the groups tested at ninety days showed leakage than at the thirty-day testing period. This study suggests that orthodontic adhesives may be susceptible to microleakage and that this may present problems clinically. However, long-term, well controlled investigations must be undertaken before more definite conclusions can be drawn concerning the effect on bond strength and enamel integrity.
A Study of Tensile Bond Strengths of Three Bracket Base Surfaces
(1984) Avant, Daniel A.
The present study was designed to test the tensile bond strength of two new bracket base designs and compare the results with those of the study by Higgins using Ormesh brackets. It was hypothesized that the visible increase in surface roughness of the two new bracket bases over the conventional (Ormesh) mesh would increase the tensile bond strength of the bracket. Sixteen DuraLingual mesh brackets and the acid-etched bracket bases were fabricated and bonded to human maxillary bicuspid teeth with a Bis-GMA compound adhesive as described by Higgins. After 24 hours, the bases were subjected to tensile bond strength testing until failure in tension and 10 brackets tested from each group were used to calculate the results. The following results were recorded: (1) The mean tensile bond strength of DuraLingual mesh and acid-etched bracket bases were significantly greater than the Ormesh wire mesh. (2) The mean tensile bond strength of the acid-etched base was significantly greater than the DuraLingual mesh. The visually apparent surface roughness and intricate microscopic voids and pits created by electrolytically-etching a smooth bracket base surface may have contributed to greater mechanical retention in this bracket compared to a smooth wire mesh bracket base (Ormesh) and a cast mesh (DuraLingual).
Tensile Bond Strength of Light-Activated Composite for Bonding Metal and Ceramic Brackets
(1989) Shepherd, Jeffrey Dean; Roberts, W. Eugene; Moore, B. Keith; Shanks, James C.; Hennon, David K.; Nelson, Charles L.
Visible light-activated composite adhesives offer several advantages over conventional autopolymerizing adhesives such as extended working time, immediate ligation and easier cleanup. This study compared in vitro tensile bond strength and site of failure of a new light-activated adhesive and a commonly used two-paste adhesive for bonding ceramic and metal brackets. Manufacturer recommended light-activation times were evaluated using hardness as an indicator of cure. Light-activated composite specimens 0.3 mm in thickness were cured beneath metal brackets for 30 seconds and ceramic brackets for 10 seconds. Knoop hardness values were determined at various time intervals over a seven-day period. An evaluation of the hardness testing data indicated that manufacturer recommended cure times for both brackets were adequate. A significant increase in hardness over time also was noted for all specimens. Mean tensile bond strength comparisons were determined by dividing 88 human maxillary premolars into four groups of 22 specimens each. Each group had either metal or ceramic brackets bonded with either two-paste or light-activated adhesive. After bonding, specimens were thermocycled and stored in a humidor set at 37°C for seven days. Ceramic bracket specimens underwent further preparation to decrease bracket failures during debonding. At the end of seven days specimens were subjected to tensile stress using an Instron mechanical testing machine until failure occurred. No significant differences in tensile bond strength were found between light-activated and two-paste adhesives when similar brackets were used. Ceramic brackets bonded with either adhesive had significantly higher bond strengths than metal brackets bonded with the same adhesive. Nineteen ceramic brackets failed during debonding; however, tensile bond strengths of these specimens were not significantly different from those specimens where adhesive failure occurred. Specimens were viewed by light microscopy to determine percent bond failure at enamel surface. Groups using ceramic brackets tended to have a higher percent bond failure at enamel surface than did metal bracket groups. High bond strengths demonstrated by ceramic brackets coupled with the brittleness of the bracket itself requires special attention during debonding to avoid enamel damage. Early light-cured adhesives were not practical due to slow setting times plus their inability to cure beneath metal brackets. The adhesive tested in this study appears to have overcome these problems when manufacturer's recommended cure times are used.
Tensile Bond Strength of Light-Activated Glass Ionomer for Bonding Metal and Ceramic Brackets
(1990) Wentz, Todd Zane; Roberts, W. Eugene; Moore, B. Keith; Shanks, James C.; Hennon, David K.; Garetto, Lawrence P.; Simmons, Kirt E.
Visible light-activated glass ionomer offers several advantages over conventional autopolymerizing adhesives, such as extended control of working time, immediate ligation, fluoride release, and a chemical bond to enamel. This study compared in vitro tensile bond strength of a new light-activated glass ionomer with that of a chemically-cured glass ionomer for bonding ceramic and metal orthodontic brackets. The manufacturer's recommended light-activation time of 30 seconds was evaluated by Knoop hardness testing. Specimens cured for 30 and 60 seconds were evaluated with Knoop hardness testing at various time intervals over a 24-hour period. An evaluation of the data indicated that the manufacturer's recommended cure time was adequate. Human maxillary premolars were divided into six groups of 20. Each group was bonded with either light-activated glass ionomer or a chemically-cured glass ionomer utilizing either metal or ceramic brackets. After bonding, specimens were thermocycled and stored in water at 37°C for 14 days. After the 14-day storage period specimens were tested in the tensile mode of an lnstron testing machine until failure. Ceramic brackets were found to have a significantly greater mean tensile bond strength than metal brackets when light-activated glass ionomer was used as the bonding agent. Mean tensile bond strength of metal brackets bonded with light-activated glass ionomer were significantly greater than metal brackets bonded with a chemically-cured glass ionomer. Ceramic brackets had a negligible bond strength when bonded with a chemically-cured glass ionomer. The light-activated glass ionomer tested in this study appears to have an adequate in vitro mean tensile bond strength to be considered for an orthodontic bonding adhesive.
The Use of an Adhesion Promoter in the Bonding of Orthodontic Brackets
(1987) Roberts, Larry Don; Garner, LaForrest D.; Shanks, James C., Jr.; Moore, B. Keith; Baldwin, James J.; Detamore, Robert J.
This study was designed to determine whether the use of a proprietary adhesion promoter would increase the bond strength of an orthodontic BIS-GMA direct bonding adhesive system to tooth enamel. Another purpose was to determine whether use of the promoter would allow a decrease in the traditional etch time of 60 seconds, while maintaining adequate bond strength. Such a reduction would result in less damage to the tooth. A total of 150 bicuspid teeth were mounted in a testing jig, and orthodontic brackets were bonded according to their testing group. The teeth were divided into two groups, one group bonded with the adhesion promoter and one without. Each group was subdivided into three subgroups of 25 samples each, with etching times of 60, 30, and 15 seconds. After bonding, the samples were stored in water at 37°C 24 hours before being thermocycled 2500 cycles. Thermocycling range was 15-55°C. The samples were then returned to the 37°C storage until testing. One week after bonding the samples were tested in tension using an Instron testing machine. The location and force required to produce bond failure were recorded. Only two samples of the 136 samples tested had bond failure other than at the resin-bracket interface. These two fractures were cohesive in nature. All groups were compared using a two-way analysis of variance. There was no significant difference in bond strength between 15, 30 and 60-second etch times. This study indicates that etch times can be reduced from the traditional 60-second etch time and still maintain adequate bond strength. Many resin manufacturers continue to recommend 60-second etch times in their directions for use. The findings of this study indicate that this practice is no longer necessary. The adhesion promoter has been shown by other means to increase bond strength. However, this study failed to prove that the adhesion promoter increases the bonding strength when tested with orthodontic brackets, since all but two samples failed at the resin-bracket interface.

Browsing by Subject "Bonding, Dental"

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