AN 8 MONTH CLINICAL TRIAL OF BOND FAILUES WITH FOUR DIFFERENT TYPES OF ORTHODONTIC ADHESIVES

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1 AN 8 MONTH CLINICAL TRIAL OF BOND FAILUES WITH FOUR DIFFERENT TYPES OF ORTHODONTIC ADHESIVES G. Basaran 1, T. Özer 1, O. Hamamci 2 Dicle University, Orthodontics Department of Faculty Dentistry, Diyarbakır, Turkey 1 Dicle University, Orthodontics Department of Faculty Dentistry, Diyarbakır, Turkey 2 ABSTRACT In this study the bonding survival of total etching and self etching composite resins (Relya-Bond, Kurasper F, Ideal 1, Prompt L pomp with Transbond XT) for orthodontic purposes were compared. A sample of 20 patients were treated with fixed appliances. The treatment group consisted of 10 girls and 10 boys who were years old. A split mouth technique was used. The patients were followed for a period of 8 months. Bond failures were recorded in each patient s special record, with the time of bond failure identified as the date when bond failure was noticed. Bond failure rates and the corresponding bracket survival curves were plotted using the Kaplan-Meier product limit estimate. Bracket survival distributions were then compared with a student t test. The type of the bonding agent did not influence the bracket survival rate significantly (p >.05). In conclusion, Self etching primers could be used as an alternative to conventional etching adhesive systems. Introduction Orthodontic brackets are routinely bonded to enamel using the acid etch technique in conjunction with a composite type orthodontic adhesive. Conventional orthodontic adhesive systems use three different agents (an enamel conditioner, a primer solution and an adhesive resin). A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single acidic primer solution for simultaneous use on both enamel and dentin(1, 2). In the early 90 s, maleic acid was introduced as an alternative etching material in an attempt to control the depth of the enamel etch. The main feature of the single step etch/primer bonding systems is that no seperate acid etching of the enamel is required; the adhesive agent itself has an acid component (maleic acid) that demineralizes tooth structure in the same manner as the phosphoric acid (3). Barkmeier and Ericson (4) compared the use of maleic acid with phosphoric acid in vitro and reported that the resulting bond strenghs were essentially similar with each other. Scanning electron microscopy of the enamel surfaces treated with maleic acid and phosphoric acid showed similiar morphologic patterns. Bishara et al. (5) suggested that, although the mean shear bond strength of self-etch primer system was significantly less than that of the phosphoric acid group, it was still acceptable. A commonly encountered problem is the bond failure of a bracket during treatment. Various factors can contribute to the likelihood of a bond failure, including operator technique, patient behaviour, variation of the enamel surface and bracket properties. One of the purported advantages of a self etching primer system is the easy application technique. So the bonding failures that 163 Biotechnol. & Biotechnol. Eq. 20/2006/1

2 are caused mainly by the operators or technique are omitted by using self etching techniques (6-8). There are numereous studies (6, 9-12) comparing the bonding strength of total etched and self etched brackets in vitro, but there is a lack of information from in vivo outcome reports. The purpose of this clinical evaluation was to compare four different adhesives for eight months in vivo. Two of these adhesives were self etching and light curing composite resins, the other two were conventional etching systems, except one which was a chemically activated adhesive. Materials and Methods The subjects of this study were patients seeking orthodontic treatment at the department of orthodontics, faculty of dentistry, University of Dicle. 20 consecutive patients (10 male, 10 female; age range: 16-19) requiring orthodontic treatment by means of fixed appliances were selected and treated by the first author who was an experienced orthodontist. All of the patients had required non-extraction treatment. Enamel surfaces presenting with caries, fillings, gingival hyperplasia or congenital enamel defects were excluded from the study. Another selection criteria was the absence of occlusal interferences on any of the bonded brackets, to eliminate the influence of trauma on failure rate. The adhesives were randomly allocated using the split mouth design. The oral cavities of each patient were divided into four quadrants. The bonding pattern of each patient was randomly alternated for each patient in order to assure an equal distribution of adhesives in each quadrants. Patients were randomly divided into four groups. In the first group upper right quadrant was bonded with the first adhesive, upper left quadrant with the second adhesive, lower right quadrant with the third adhesive, lower left quadrant with the fourth adhesive. In the other groups, the adhesive used for the quadrants were rotated in a clockwise direction. This randomly alternated split mouth design was used in order to eliminate any bias that have been introduced from the clinician being right handed. All teeth, except the molars, were bonded directly. The first quarter of the brackets were bonded using a conventional etching nomix chemical cured composite resin (Relya-Bond, Reliance Orthodontic Products Inc., Itasca, Illinois, USA), the second quarter were bonded with a conventional etching light cured composite resin (Kurasper F, Kuraray Medical Inc.,Okayama, Japan). The other quarters were bonded using two step self etching light cured composite resins. The third quarter was bonded with the same adhesive and composite (Ideal 1,GAC International, Inc, Islandia, USA) but the fourth quarter was bonded with a different adhesive and a composite resin which were Adper Prompt L-Pop (3M Espe AG, Seefeld, Germany) and Transbond XT as a composite resin (3M Unitek, Monrovia, USA). Stainless steel foil mesh based brackets were used for all of the patients (Straight-line, G&H wire company, Indiana, USA). A standardized protocol of tooth preparation and bracket bonding was adopted for all patients. After fitting and cementing molar bands on the first molars, all teeth were isolated and cleansed with a mixture of water and pumice using a rubber polishing cup in a low speed hand piece. The teeth were rinsed with water and dried with an oil-free air syringe. The first operator carried out all of the bonding procedures in order to standardize the operator variables. For conventional acid etch quadrants, 37 percent phosphoric acid gel was applied to the enamel surface and left in place for 15 to 30 seconds before rinsing with water and air dried until the enamel was frosty white. Then etched enamels were coated with adhesive primers via a microbrush. When all Biotechnol. & Biotechnol. Eq. 20/2006/1 164

3 the teeth in one arch were primed a gentle air burst to each tooth was directed and light cured for 10 seconds. After applying adhesive to the bracket base, the bracket was positioned on the tooth, flash composite was removed and it was light cured for 20 seconds from the mesial, 20 seconds from the distal of the tooth. While using chemically cured adhesive material, the same acid etching and priming procedures were used, but light curing was not needed. After applying a thin layer of primer, composite resin was placed onto the bracket base, and the brackets were positioned onto the tooth with fingertip pressure within 15 seconds. Flash composite was then removed with an explorer. For self etching primer quadrants, one self etching primer had a brush on the tube and it was applied to the tooth by means of this brush. The other one had seperate packages containing self etching components. They were mixed into each other with applying finger pressure on the packages. Both of them were agitated onto the enamel surface for three seconds and air dried for one second. After applying adhesive to the bracket base, the bracket was positioned on the tooth, flash composite was removed and it was light cured for 20 seconds from the mesial, 20 seconds from the distal of the tooth. For each case a similar treatment approach (e.g. archwire sequence) was adopted in the context of the straight wire technique. The patients were followed for a period of 8 months. All patients received the same instructions and were controlled at 3-4 week intervals. Bond failures were recorded in each patient s special record, with the time of bond failure identified as the date when bond failure was noticed. If the bond failure had not been noticed by the patient, then the appointment day was noted as the bracket failure day. The second bond failures were not considered because the bond strength could be affected due to some other factors. Patients were instructed to brush teeth with a manuel toothbrush using a fluoride containing toothpaste. Statistical analysis Bond failure rates during a period of 8 months were estimated for each adhesive system and the corresponding bracket survival curves were plotted using the Kaplan- Meier product limit estimate. Bracket survival distributions with respect to adhesive material, tooth location (upper-lower, anterior-posterior, right-left side) and patient s gender were then compared with student t test. Results and Discussion A total of 23 bond failures of 400 teeth were registered during the 8 months of the observation period. Failure rates were 5% for Rely-a-bond, 5% for Kurasper F, 7% for Ideal 1 and 6% for Prompt L Pop and Transbond XT (Table 1). The corresponding bracket survival curves were plotted using the Kaplan-Meier product limit estimate (Figure). The bond failure rates with respect to time can be seen (Table 2). The bond failures occured especially in the posterior region for all kinds of adhesives (Table 3). There were no statistically significant differences between right and left sides, upper and lower arches (Tables 4, 5). Also no difference was found in the frequency of bond failures with respect to the patient s gender (Table 6). In vitro investigation of bond strength plays an important role in evaluating the bonding efficiency of newly introduced orthodontic bonding materials (6, 9-12). While it is true that certain aspects of physical and chemical adhesive properties may be clarified by in vitro studies, the actual performance of the system can only be evaluated in the enviroment where it was intended to function. Therefore, the most reliable method to illustrate the clinical efficiency of new bonding materials is the evaluation of clinical bond failure rate 165 Biotechnol. & Biotechnol. Eq. 20/2006/1

4 TABLE 1 Bond failure rates for the orthodontic adhesives Promt L Pop +Transbond Ideal 1 Kurasper Rely-a-bond p n Failure n Failure n Failure n Failure TABLE 2 Bond failure percentage as a function of time Failure/month Promt L Pop+Transbond Ideal Kurasper Rely-a-bond Figure. Bracket survival distribution of all orthodontic adhesives plotted against time. using randomized controlled clinical trial methodology. So this in vivo study is usefull to evaluate the clinical success of three different light curing adhesives (two self etching and one conventional etching system) in comparison with a conventional etching chemical curing material. This conventional etching chemical curing material served as a control group. There are challenging reports about the bonding strengths of self etching and conventional etching systems. Some studies have found no significant difference (6, 13), but others have reported better results with conventional acid etching systems (5, 14). Studies which indicate better results with conventional acid etch systems, also report that self etching primers show lower but clinically acceptable results (5, 15). Failure rate of a bonding material is often used to indicate the clinical performance of bonding adhesives and it allows comparisons to be made between studies. Reported failure rates for orthodontic brackets in vivo range from 0.5 percent to 16 percent; the average reported clinical bond failure Biotechnol. & Biotechnol. Eq. 20/2006/1 166

5 TABLE 3 Bond failure rates anterior vs. posterior teeth Anterior Posterior p n Failure n Failure * * p<0.05 TABLE 4 Bond failure rates right vs. left side of the dental arch UR UL LR LL p n Failure n Failure n Failure n Failure rate of all orthodontic bonds is approximately 6 percent (13, 14, 16). In our study overall failure rates for both self etching and conventional etchings systems were essentially similiar and it was ranging from 5 percent to 7 percent. The relationship between bond failure and region of the dental arch has not received much attention in previously published clinical studies. The few reports available are contradictory since they found more bond failures in the left (16) or the right side of the dental arch (17). There are several possible factors in determining the difference of bond failure rate between the two regions: the clinicians being righthanded could make access, bracket placement and moisture control easier on the right side, the habitual side during mastication and the difference in pressure exerted during toothbrushing (18). In our study, there were no differences between the right and left sides as it has been published in some studies before (15) (Table 4). The gender of the patient did not influence the bond failure rates obtained in the present study (Table 6) confirming the results of previous clinical reports (17, 19, 20). There are reports of statistically significant differences between the operators in terms of bracket survival time (19-21). In our study, the bond failures were distributed equally. This could be attributed to the Bond failure rates upper vs. lower arch TABLE 5 Upper Lower p n Failure n Failure Bond failure rates female vs. male TABLE 6 Female Male p n Failure n Failure clinician s experience, treatment approach or the mechanics used in our study. Although some authors reported more failures in the lower dental arch (21-23). There were no statistically significant differences between upper and lower jaws in our research which was an aggreement with previous clinical studies (16, 24, 25). The position of the bracket in the dental arch had an influence on the failure rates of the brackets. As it has been reported in most previous studies, the highest failure rate of orthodontic brackets occurred in the posterior region when compared with the anterior region (16, 21, 23). The high incidence of bracket failures in the posterior teeth could be associated to a number of factors, such as poor moisture control, (21, 23, 26) the partial eruption of second premolars (27, 28), the heavier occlusal forces exerted on the posterior teeth during mastication (16, 29) and the larger amount of aprismatic enamel on premolars affecting the quality of micromechanical bond (21). By reducing the number of steps during bonding, clinicians are able to save time and reduce the potential for error and contamination during the bonding procedure. Different commercially available self etching primers have the potential to successfully bond orthodontic brackets. The results of this present comparative clinical study encourages the usage of self etching primers for routine orthodontic bonding as 167 Biotechnol. & Biotechnol. Eq. 20/2006/1

6 a viable alternative to the conventional two stage bonding systems. Conclusions Different commercially available self etching primers can be used in daily orthodontic practice as an alternative method to conventional etching and priming systems. REFERENCES 1. Chigira H., Koike T., Hesegawa T., Itoh K., Wakumoto S., Hyakawa T. (1989) Dental Materials Journal., 8, Nishida K., Yamauchi J., Wada T., Hosada H. (1993) Journal of Dental Research, 72, p Miller R.A. (2001) Journal of Clinical Orthodontics, 35, Barkmeier W.W., Ericson R.L. (1994) American Journal of Dentistry, Bishara S.E., VonWald L., Laffoon J.F., Warren J.J. (2001) American Journal of Orthodontics and Dentofacial Orthopedics, 119, Arnold R.W., Combe E.C., Warford J.H. (2002) American Journal of Orthodontics and Dentofacial Orthopedics, 122, Richter D.D., Nanda R.S., Sinha P.K., Smith D.W. (1998) Angle Orthodontist., 68, Pashley D.H., Tay F.R. (2000) Dental Materials, 17, Larmour C.J., Stirrups D.R. (2001) Journal of Orthodontics, 28, Linklater R.A., Gordon P.H. (2001) Journal of Orthodontics, 28, Cacciafesta V., Sfondrini M.F., Melsen B., Scribante A. (2004) European Journal of Orthodontics, 26, Sunna S., Rock W.P. (1999) British Journal of Orthodontics, 26, Aljubouri Y.D., Millett D.T., Gilmour W.H. (2004) European Journal of Orthodontics, 26, Ireland A.J., Knight H., Sherriff M. (2003) American Journal of Orthodontics and Dentofacial Orthopedics, 124, Mavropoulos A., Karamouzos A., Kolokithas G., Athanasiou A.E. (2003) Journal of Orthodontics, 30, Sunna S., Rock W.P. (1998) British Journal of Orthodontics, 25, Kinch A.P., Taylor H., Warltier R., Oliver R.G., Newcombe R.G. (1998) American Journal of Orthodontics and Dentofacial Orthopedics, 94, White L. (1983) American Journal of Orthodontics, 83, Millet D.T., Hallgren A., Cattanach D., Mc Fadzean R., Pattison J., Robertson M., Love J. (1998) Angle Orthodontist, 68, Hitmi L., Muller C., Mujajic M., Attal J.P. (2001) American Journal of Orthodontics and Dentofacial Orthopedics, 120, Lovius B.B.J., Pender N., Hewage S., O Dowling I., Tomkins A. (1987) British Journal of Orthodontics, 14, Linklater R.A., Gordon P.H. (2003) American Journal of Orthodontics and Dentofacial Orthopedics, 123, Trimpeneers L.M., Dermaut L.R. (1996) American Journal of Orthodontics and Dentofacial Orthopedics, 110, Cacciafesta V., Bosch C., Melsen B. (1998) Clinical Orthodontics and Research, 1, O Brien K.D., Read M.J., Sandison R.J., Roberts C.T. (1989) American Journal of Orthodontics and Dentofacial Orthopedics, 95, Zachrisson B.U. (1977) American Journal of Orthodontics, 71, Mizrahi E. (1982) Angle Orthodontist, 52, Underwood M.L., Rawls H.R., Zimmerman B.F. (1989) American Journal of Orthodontics and Dentofacial Orthopedic, 96, Gorelick L., Geiger A.M., Gwinnett A.J. (1984) American Journal of Orthodontics, 86, Biotechnol. & Biotechnol. Eq. 20/2006/1 168