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A posttreatment survey of direct bonding of metal brackets
A posttreatment survey of direct bonding of metal brackets George V. Newman, West Ormge. N. J.
D.D.S.
A
n evaluation of sealant-composite bonding systems employing metal brackets in routine orthodontic treatment and posttreatment should be of interest to the profession. r It is the purpose of this article to report on the use of an autopolymerizing system comparing a liquid-powder material with a paste-paste material formulated and developed by the author. The adhesive systems used were essentially a bisphenol A-glycidyl methacrylate composite material. Success rates are compared when metal brackets are used. Although plastic brackets are also employed, they are usually bonded on the upper anterior teeth for esthetic purposes and are not included in this study.2 The liquid-powder system is called Bondmor I and the paste-paste material is termed Bondmor II.* A primer (sealant) is employed in both systems. BONDING
RESIN
The resin matrix of Bondmor I and II consists of bisphenol A-glycidyl methacrylate and resin diluents (mono- and dimethacrylates). Bisphenol A-glycidyl methacrylate is a thermosetting acrylic resin derived from epoxy resins. It has the fast-setting properties of the acrylics, is highly cross-linked, and possesses the dimensional stability of the epoxies.3 MATERIAL
When the liquid and powder or paste and paste are mixed, free radical polymerization occurs when the catalyst (benzoyl peroxide) and base (accelerator-tertiary amine) react. The paste-paste material contains silane-treated quartz, softer calcium carbonate, and fumed silica, whereas the liquid-powder composite contains a lithium-aluminosilicate, as tillers. The fillers reduce the coefficients of thermal expansion, affect thixotropy, increase thermal shock resistance, and reduce shrinkage, enhancing adhesion.J The primer (sealant) has essentially the same resin system: since it has no filler, it “wets” the tooth enamel more readily. The primer chemically reacts with the composite adhesive. METHOD
The patients in this study were treated by me in my private practice. A total of 2.218 metal brackets were bonded to the teeth of I80 orthodontically treated children, IO to I4 years of age. Treatment time varied from 14 to 32 months, with a mean range of 22 months. The cases treated can be categorized as follows: Class I, 64 cases; Class II, Division I. 90 cases; Class II, Division 2, 23 cases: Class III, 3 cases. There were 110 *General
Orthodontic
0002.9416/7X/0274-0197$01.00/0
Lab.. 0
Box
298,
West
1978 The C. V. Mosb)
Orange. Co.
N. J. 07052.
197
Am. J. Orrhod. Au@sr 1978
Fig. 1. A, Bonded Begg brackets on upper and lower anterior teeth. B, A Class II, Division protl rusion in a four first premolar extraction case. C, Posttreatment intraoral photograph effec :t of adhesive on tooth structures. Excellent gingival health is apparent.
Fig.
2. LetY, Bonded
Begg
Chun-Hoon
brackets.
Right,
Bonded
edgewise
v
1 bimaxilla shows no ill
brackets.
nonextraction and 70 extraction cases. There were 94 cases treated with a modified Begg technique (Begg Chun-Hoon and Begg brackets) (Fig. I); 86 were treated with the edgewise technique. When the edgewise technique was used (Fig. 2), an 0.022 by 0.028 inch (0.559 by 0.71 1 mm.) edgewise slot was employed on the mandibular molars and the maxillary molars had 0.022 by 0.028/0.050 inch (0.559 by 0.71 I/I .270 mm.) double tubes. The canines were retracted with reciprocal coil springs on 0.018 inch (0.457 mm.) arch wires or 0.018 by 0.025 inch (0.457 by 0.635 mm.) Bull loops. Although rotation
Volume 14 Number 2
Direct bonding
Fig. 3. A, Applying surface-treating agent to tooth surfaces. B, Warm air dryer condensation and to accelerate cure of primer and adhesive. C, Positioning placing a small amount of adhesive on the mesh backing. D, Use of bracket against tooth enamel to obtain proper bracket height.
of metal brackets
199
is used to prevent vapor left lateral bracket after aligner to press bracket
was a problem, it was usually solved by using loops, lingual cleats, or off-setting of the brackets. When the Begg technique was used, all the stages and techniques were the same as those advocated by Begg and Kesling for the maxillary arch; however, at the end of the second stage the mandibular arch wire was inserted in the edgewise slot to effect arch symmetry and axial control. A double tube-O.002 by 0.028 inch (0.559 by 0.711 mm.) over 0.036 inch (0.914 mm.)-was used on the lower first molars; the upper molars had 0.036/O.OSO inch (0.914! I.270 mm.) double tubes. Headgear was employed where indicated, particularly to aid in depression and lingual root torque of the maxillary anteriors. An edgewise arch wire with labial root torque was inserted, when indicated, in the mandibular edgewise slot on the finishing stage.“, B The criterion for selection of these patients was that they had at least six teeth bonded. They were not selected for ease of bonding. It was difficult to bond the teeth of several patients because of a small oral aperture and excessive salivation. In addition, partially erupted premolars and second molars were difficult to bond. No drugs were used to
200
Am. J. Orrhod. Augurr 1978
NeMwml
decrease salivation. The bonding areas were maintained dry with Dri-Angles,* cotton rolls, hygoformic saliva ejectors,? and lip retractors. Maxillary second molars were not bonded and only 40 mandibular second molars were bonded. The bonding procedure was as follows: the maxillary arch was bonded first and then the mandibular arch was bonded. Occasionally the maxillary arch was bonded, the patient was dismissed, and the mandibular arch was bonded at another visit. In some patients the maxillary arch only, was completely bonded, whereas in others the maxillary and mandibular anterior teeth were bonded while the posterior teeth were not bonded. TECHNIQUE
FOR BONDING
For simplicity’s sake, let us assume that the maxillary anterior teeth were bonded first. The teeth were given a thorough proplylaxis with a coarse pumice and a bristle brush. The teeth were then isolated with Dri-Angles, cotton rolls, hygoformic saliva ejectors, and lip retractors, and air dried. The enamel surfaces were treated with 50 per cent phosphoric acid for 1 minute (Fig. 3). The etched surfaces were rinsed with water from a rubber bulb syringe and air dried until the surfaces took on a dull, frosty, whitish appearance. Two drops of promoter and two drops of catalyst were mixed with a foam pellet on a polyethylene-coated mixing pad or cold glass slab for 5 to 10 seconds. This primer was painted on the entire tooth surface with the foam pellet for both adhesives. A warm air dryer was then used. When the liquid-powder system was used, one scoop of powder was dispensed on a cold slab or mixing pad and 3 drops of liquid were added to bond two or three teeth. When the paste-paste composite material was used, equal parts of catalyst and base material were placed on a mixing pad or cold slab$ and mixed for I5 seconds. Four to six teeth could be bonded with a mix about 5 mm. in diameter and 1 mm. in height. The brackets for both materials were held with a tweezer and the adhesive was placed on the base of the bracket. The brackets were then pressed into the desired position. A bracket aligner was used to align and press the bracket against the tooth for a few seconds. The author prefers to use a warm air dryer which the patient holds while “playing” the warm air over the bonded surfaces. This prevents moisture condensation and accelerates cure. Arch wires can be inserted 5 to 10 minutes after bonding.7 Use of disposable mixing pads requires more frequent small mixes to bond, whereas a cold slab allows for one mix for six or more brackets. Refrigeration increased the shelf life of Bondmor II. One advantage of Bondmor I (liquid-powder) is that shelf life is not a problem. It should be noted that the maxillary anterior teeth had the highest success rate, since they were readily accessible, which made it easier to maintain dryness (Table I). The premolars, when partially erupted, had to be bonded near the gingiva. Cervical fluids from the pulp and gingival fluids make bonding difficult, since it is difficult to dry these areas. After two repeated bondings of the premolars and molars, bands were cemented with Cementex (a composite dental cement).8’ ’ When deep bites are present it is advisable to use a bite plate to open the bite prior to bonding the lower anteriors. Headgear forces against the upper molars eventually broke *Theta tNorth #Appco
D&Angles, Dental Health Products, Inc., Niagra Falls, Pacific Dental, Inc., Kirkland, Wash. Mfg. Co., Mini-Cold Station, Chula Vista, Calif.
N. Y.
Volume 14
Number
Table
Direct
2
I. Number
of brackets
bonded
to 2,218
Bondmor No.
teeth
and percentage
I liquid-powder
bonded
% success
bonding
oj’metal
of posttreatment Bondmor No. bonded
brackets
201
success
II paste-paste % success
Maxilla:
First molars Second premolars First premolars Canines Lateral incisors Central incisors
46 98 82 174 180 180
76.6 77.3 87.0 94.2 95. I 96.4
38 94 98 156 150 152
78.6 77.3 89.8 93.0 94.4 95.3
22 58 80 60 88 104
73.4 75.0 78.2 88.0 90.5 89.6
18 40 52 60 94 94
70.0 72.3 80.4 87. I 89.2 88.8
Mandible:
Second molars First molars Second premolars First premolars Canines Incisors
the bonds, due to the peel and cleavage forces. However, high-pull headgear with hooks soldered anteriorly on round or edgewise arches did not tend to break the adhesive joints. The attachments primarily used had mesh backings. Their curvatures were adapted to the teeth prior to bonding. Perforated brackets were also employed and were not as satisfactory clinically. The new mesh/pad brackets seem quite promising and bond well, since they are well adapted to the curvature of the teeth, which enhances bonding.*? With experience, direct bonded brackets can be placed fairly accurately by sighting the middle third of the crown or using a measuring gauge. When tying edgewise brackets with ligatures it was found that using lighter ligature wire-O.007 inch (0.178 mm.) instead of 0.010 inch (0.254 mm.)-bracket failure was decreased. Excessive force in tying and pinning arch wires should be avoided. Although I used pretorqued brackets, 1 prefer the ARTS torquing arch for the edgewise technique and the von der Heydts torquing auxiliary for the Begg technique. Uprighting of maxillary canines seemed slower for bonded attachments than banded canines in the Begg technique. Corrections of rotations are more difficult to accomplish with bonded brackets than with bands. RESULTS Table I indicates the results obtained after treatment and removal of brackets. There seems to be no significant difference in the success rate between the liquid-powder and paste-paste materials; additionally, the results are comparable to Zachrisson’s.’ The success rate was the highest in the maxillary anterior teeth and decreased progressively posteriorly. The mandibular anteriors had the second highest percentage of success. The posterior teeth had the lowest success rate because of difficulty in maintaining dryness in these areas and excessive forces exerted by appliances and mastication. *American Orthodontics, Sheboygan, tOrmco Corp., Glendora, Calif. $Atlanta Orthodontics, Atlanta, Ga. IRocky Mountain, Denver, Colo.
Wis
202
Am. J. Orthod. AuguFt 1978
Newmutt
Fig. 4. Scanning electron photomicrograph. enamel. Note peaks, valley, and microporosities extensive bonding surface. (x 10,000.)
Surface-treated (50 per cent phosphoric acid) tooth where adhesive can flow and polymerize, creating
DEBONDING
Removal of brackets was accomplished by squeezing the mesial-distal comers of the bracket at the adhesive joint and twisting (peel and cleavage forces) gently with a ligature cutter. The adhesive remnants were removed with a sickle-scaler, band remover (ETM* No. 348 or Rocky Mountain No. 347), and/or Cavitroni machine. Pumicing with a prophylaxis paste was sufficient to bring the teeth back to their normal appearance”, I1 (Figs. 4 to 6). For experimental purposes, attachments were bonded with Protect0 and Concise. It was more difficult to remove adhesive remnants from the tooth surfaces with these adhe*ETM, Monrovia, Calif. tL. D. Caulk Co., Milford,
Del
Volume 14 Number 2
Direct bonding of metal brackets
203
Fig. 5. Scanning electron photomicrograph. Bondmor I adhesive remnant on mesh surface after removal of metal bracket. Note tags of adhesive that flowed into tooth surface microporosities. (x 2,000.)
sives than with Bondmor I and II. This may be attributable to several factors: Bondmor I and II are less chemically cross-linked, have less filler percentagewise, and are less viscous. The fillers in Concise* and Protectot contribute to hardness, abrasion resistance and tensile and compressive strengths; however, these mechanical properties make debonding more difficult and apparently do not contribute to bond strength. Bondmor I and II were formulated to promote bonding and to concomitantly allow for ease of removal of the adhesive remnants, because of the possibility of damaging the enamel surface, which can be viewed in scanning electron photomicrographs.12* l3 The possibility of “latent” erosion’* before and after debonding is a factor that requires additional study and is difficult to predict prior to bonding. *3M tLee
Co., St. Paul, Pharmaceuticals,
Minn. South
El Monte.
Calif.
204
Am. J. Orthod. Augwt 1978
Newman
Fig. 6. Scanning Bondmor pattern.
electron photomicrograph I adhesive remnant with a scaler, This is the stage prior to prophylaxis
ORAL
HYGIENE
showing tooth surface immediately after the Cavitron, and light pumicing. Note characteristic and acquisition of the salivary tooth pellicle.
removal of prism end (22,000.)
At every visit an explorer was inserted and “wiped” between the interproximal spaces of the patient’s incisors to dislodge bacterial plaque and prevent caries. Toothbrush instruction with a fluoride tooth paste was stressed and fluoride oral rinse prescriptions were given to the patients. Surprisingly, little caries was found interproximally. Premolars and molars that were difficult to bond because of inaccessibility, excessive salivation, severe rotations, and poor patient cooperation were banded with Cementex” (containing 5 per cent sodium monofluorophosphate). l5 Decalcifications were rarely seen after removal of bands when Cementex was used. *General
Orthodontic
Labs.,
West
Orange,
N. J
Vo6ume 74 Number 2
Direct bonding
of metal brackets
205
Severely rotated and short-crowned mandibular anterior teeth were difficult to bond and interproximal bonding occasionally occurred. Dental floss or an interproximal tooth stripper was helpful in opening contacts. In several individual children there was a high percentage of loose attachments, confirming previous in vitro and in vivo studies that there was a great deal of individual variation. A controlled research survey conducted by the West Orange Health Department, in which children in a fluoride-rinsing group rinsed daily with a 0.1 per cent solution of sodium fluoride at night after toothbrushing, showed a 35 per cent decrease in caries. Consequently, a fluoride rinse should be used daily by all patients after bonding and banding.* Although not shown in the Table I statistics, it was clinically noted that there were fewer decalcifications in patients who had the primer applied to the tooth surfaces prior to application of the adhesive than when the adhesive alone was used. Furthermore, bond strength was increased and removal of adhesive remnants was facilitated.16 The increase in bond strength when the primer was used was confirmed in in vitro tests as well. l’, I8 SUMMARY
A posttreatment evaluation of 180 orthodontically treated patients having 2,218 bonded brackets was made with a sealant and liquid-powder and paste-paste, chemically polymerized composite materials. All brackets were bonded by the author employing edgewise, Begg, and Begg ChunHoon brackets. By lightly tying 0.007 (0.178 mm.) inch ligatures and lightly pinning, less force was exerted on the brackets, tending to prolong the adhesive bond. Esthetics and gingival conditions were improved by using minimal amounts of adhesive material. The use of the primer (sealant) tended to enhance adhesion and decrease decalcifications. The liquid-powder success percentages were similar to the paste-paste composite material and compared favorably to Zachrisson’s findings. The data from Table I indicate that clinically, the greatest percentage of bonding success is primarily in the six maxillary anterior teeth and secondarily in the six mandibular teeth and premolars. Bonding of the first molars that may require headgear, lingual arches, lingual buttons, and cleats, or bumpers is not practical in many cases over a 2- to 3-year treatment period. Peel and cleavage forces are created by these appliances tending to break the adhesive bonds. Consequently, from a practical, clinical standpoint, the author prefers to band the posterior teeth with an anticariogenic composite cement such as Cementex. Severely rotated and partially erupted second premolars are difficult to bond, since excessive salivation and poor visibility limit posterior bonding with direct bonding techniques. Reduction of dental caries and decalcifications can be accomplished with bonded attachments supplemented by sealants, fluoride mouth rinses. and the use of fluoride gels on the bonded teeth during treatment. Debonding with Bondmor I and II is facilitated by having a lower percentage of fillers, less hardness, tensile and compressive strengths, and less cross-linking than most commercial composite adhesives. *Phos-Flur,
Hoyt
Laboratories,
Needham
Heights,
Mass,
206
Am. J. Orthod. Augw 1918
Newwxm
REFERENCES 1. Zachrisson. B. V.: A posttreatment evaluation of direct bonding in orthodontics, AM. J. ORTHOD. 71: 173-189, 1977. 2. Brandt, S., Servosa, J. M., and Wolfson, J.: Practical methods of bonding, direct and indirect, J. Clin. Orthod. 9: 6 10-636, 1975. 3. Bowen, R. L.: Use of epoxy resin in restorative material, J. Dent. Res. 35: 360-369, 1956. 4. Newman, G. V.: Adhesion and orthodontic plastic attachments, AM. J. ORTHOD. 56: 583, 1969. 5. Mulie, R. M., and Hoeve, A. T.: The limitations of tooth movement within the symphysis, studied with laminagraphy and standardized occlusal films, J. Clin. Orthod. 10: 899, 1976. 6. Newman, G. V.: A biomechanical analysis of the Begg light arch wire technique, AM. J. ORTHOD. 10: 737, 1963. 7. Newman, G. V.: Current status of bonding attachments, J. Clin. Orthod. 7: 425-449, 1973. 8. Newman, G. V.: Cementex: An insoluble caries preventive cement, J. Clin. Orthod. 8: 524-527, 1974. 9. Sadowsky, P. L., and Retief, D. H.: A comparative study of some dental cements used in orthodontics, Angle Orthod. 46: I7 I - 18 I, 1976. IO. Newman, G. V., and Facq, J. M.: The effects of adhesive systems on tooth surfaces, AM. J. ORTHOD. 5% 67-75, 1971. 1 I. Silverstone, L. M.: Fissure sealants: The susceptibility to dissolution of acid-etched and subsequently abraded enamel in vitro, Caries Res. 11: 46-S I, 1977. 12. Caspersen, I.: Residual acrylic adhesive after removal of plastic orthodontic brackets: A scanning electron microscopic study, AM. J. ORTHOD. 71: 637-650, 1977. 13. Gwinnett, A. J., and Gorelick: Microscopic evaluation of enamel after debonding: clinical application, AM. J. ORTHOD. 71: 651-665, 1977. 14. Mannerberg, F.: Appearance of tooth surface as observed in shadowed replicas, Odont. Revy. Supp. 6: I IO, 1960. 15. Newman, G. V., and Cimasoni, G.: In viva uptake of fluoride by enamel from an adhesive system, Angle Orthod. 41: 236-240, 1971. 16. Newman, G. V.: Bonding plastic attachments to tooth enamel, J. New Jersey Dent. Sot. 35: 346-358, 1964. 17. Mitchem, J. C., and Turner, L. R.: The retentive strength of acid etched retained resins, J. Am. Dent. Assoc. 89: I 107. I I IO, 1974. 18. Meurman, J. H., and Nevaste, M.: The intermediate effect of low-viscous fissure sealants on the retention of resin restorative in vitro, Proc. Finn. Dent. Sot. 71: 96-101, 1975. 659 Eagle
Rock
Ave.
(07052)
D.D.S.
A
n evaluation of sealant-composite bonding systems employing metal brackets in routine orthodontic treatment and posttreatment should be of interest to the profession. r It is the purpose of this article to report on the use of an autopolymerizing system comparing a liquid-powder material with a paste-paste material formulated and developed by the author. The adhesive systems used were essentially a bisphenol A-glycidyl methacrylate composite material. Success rates are compared when metal brackets are used. Although plastic brackets are also employed, they are usually bonded on the upper anterior teeth for esthetic purposes and are not included in this study.2 The liquid-powder system is called Bondmor I and the paste-paste material is termed Bondmor II.* A primer (sealant) is employed in both systems. BONDING
RESIN
The resin matrix of Bondmor I and II consists of bisphenol A-glycidyl methacrylate and resin diluents (mono- and dimethacrylates). Bisphenol A-glycidyl methacrylate is a thermosetting acrylic resin derived from epoxy resins. It has the fast-setting properties of the acrylics, is highly cross-linked, and possesses the dimensional stability of the epoxies.3 MATERIAL
When the liquid and powder or paste and paste are mixed, free radical polymerization occurs when the catalyst (benzoyl peroxide) and base (accelerator-tertiary amine) react. The paste-paste material contains silane-treated quartz, softer calcium carbonate, and fumed silica, whereas the liquid-powder composite contains a lithium-aluminosilicate, as tillers. The fillers reduce the coefficients of thermal expansion, affect thixotropy, increase thermal shock resistance, and reduce shrinkage, enhancing adhesion.J The primer (sealant) has essentially the same resin system: since it has no filler, it “wets” the tooth enamel more readily. The primer chemically reacts with the composite adhesive. METHOD
The patients in this study were treated by me in my private practice. A total of 2.218 metal brackets were bonded to the teeth of I80 orthodontically treated children, IO to I4 years of age. Treatment time varied from 14 to 32 months, with a mean range of 22 months. The cases treated can be categorized as follows: Class I, 64 cases; Class II, Division I. 90 cases; Class II, Division 2, 23 cases: Class III, 3 cases. There were 110 *General
Orthodontic
0002.9416/7X/0274-0197$01.00/0
Lab.. 0
Box
298,
West
1978 The C. V. Mosb)
Orange. Co.
N. J. 07052.
197
Am. J. Orrhod. Au@sr 1978
Fig. 1. A, Bonded Begg brackets on upper and lower anterior teeth. B, A Class II, Division protl rusion in a four first premolar extraction case. C, Posttreatment intraoral photograph effec :t of adhesive on tooth structures. Excellent gingival health is apparent.
Fig.
2. LetY, Bonded
Begg
Chun-Hoon
brackets.
Right,
Bonded
edgewise
v
1 bimaxilla shows no ill
brackets.
nonextraction and 70 extraction cases. There were 94 cases treated with a modified Begg technique (Begg Chun-Hoon and Begg brackets) (Fig. I); 86 were treated with the edgewise technique. When the edgewise technique was used (Fig. 2), an 0.022 by 0.028 inch (0.559 by 0.71 1 mm.) edgewise slot was employed on the mandibular molars and the maxillary molars had 0.022 by 0.028/0.050 inch (0.559 by 0.71 I/I .270 mm.) double tubes. The canines were retracted with reciprocal coil springs on 0.018 inch (0.457 mm.) arch wires or 0.018 by 0.025 inch (0.457 by 0.635 mm.) Bull loops. Although rotation
Volume 14 Number 2
Direct bonding
Fig. 3. A, Applying surface-treating agent to tooth surfaces. B, Warm air dryer condensation and to accelerate cure of primer and adhesive. C, Positioning placing a small amount of adhesive on the mesh backing. D, Use of bracket against tooth enamel to obtain proper bracket height.
of metal brackets
199
is used to prevent vapor left lateral bracket after aligner to press bracket
was a problem, it was usually solved by using loops, lingual cleats, or off-setting of the brackets. When the Begg technique was used, all the stages and techniques were the same as those advocated by Begg and Kesling for the maxillary arch; however, at the end of the second stage the mandibular arch wire was inserted in the edgewise slot to effect arch symmetry and axial control. A double tube-O.002 by 0.028 inch (0.559 by 0.711 mm.) over 0.036 inch (0.914 mm.)-was used on the lower first molars; the upper molars had 0.036/O.OSO inch (0.914! I.270 mm.) double tubes. Headgear was employed where indicated, particularly to aid in depression and lingual root torque of the maxillary anteriors. An edgewise arch wire with labial root torque was inserted, when indicated, in the mandibular edgewise slot on the finishing stage.“, B The criterion for selection of these patients was that they had at least six teeth bonded. They were not selected for ease of bonding. It was difficult to bond the teeth of several patients because of a small oral aperture and excessive salivation. In addition, partially erupted premolars and second molars were difficult to bond. No drugs were used to
200
Am. J. Orrhod. Augurr 1978
NeMwml
decrease salivation. The bonding areas were maintained dry with Dri-Angles,* cotton rolls, hygoformic saliva ejectors,? and lip retractors. Maxillary second molars were not bonded and only 40 mandibular second molars were bonded. The bonding procedure was as follows: the maxillary arch was bonded first and then the mandibular arch was bonded. Occasionally the maxillary arch was bonded, the patient was dismissed, and the mandibular arch was bonded at another visit. In some patients the maxillary arch only, was completely bonded, whereas in others the maxillary and mandibular anterior teeth were bonded while the posterior teeth were not bonded. TECHNIQUE
FOR BONDING
For simplicity’s sake, let us assume that the maxillary anterior teeth were bonded first. The teeth were given a thorough proplylaxis with a coarse pumice and a bristle brush. The teeth were then isolated with Dri-Angles, cotton rolls, hygoformic saliva ejectors, and lip retractors, and air dried. The enamel surfaces were treated with 50 per cent phosphoric acid for 1 minute (Fig. 3). The etched surfaces were rinsed with water from a rubber bulb syringe and air dried until the surfaces took on a dull, frosty, whitish appearance. Two drops of promoter and two drops of catalyst were mixed with a foam pellet on a polyethylene-coated mixing pad or cold glass slab for 5 to 10 seconds. This primer was painted on the entire tooth surface with the foam pellet for both adhesives. A warm air dryer was then used. When the liquid-powder system was used, one scoop of powder was dispensed on a cold slab or mixing pad and 3 drops of liquid were added to bond two or three teeth. When the paste-paste composite material was used, equal parts of catalyst and base material were placed on a mixing pad or cold slab$ and mixed for I5 seconds. Four to six teeth could be bonded with a mix about 5 mm. in diameter and 1 mm. in height. The brackets for both materials were held with a tweezer and the adhesive was placed on the base of the bracket. The brackets were then pressed into the desired position. A bracket aligner was used to align and press the bracket against the tooth for a few seconds. The author prefers to use a warm air dryer which the patient holds while “playing” the warm air over the bonded surfaces. This prevents moisture condensation and accelerates cure. Arch wires can be inserted 5 to 10 minutes after bonding.7 Use of disposable mixing pads requires more frequent small mixes to bond, whereas a cold slab allows for one mix for six or more brackets. Refrigeration increased the shelf life of Bondmor II. One advantage of Bondmor I (liquid-powder) is that shelf life is not a problem. It should be noted that the maxillary anterior teeth had the highest success rate, since they were readily accessible, which made it easier to maintain dryness (Table I). The premolars, when partially erupted, had to be bonded near the gingiva. Cervical fluids from the pulp and gingival fluids make bonding difficult, since it is difficult to dry these areas. After two repeated bondings of the premolars and molars, bands were cemented with Cementex (a composite dental cement).8’ ’ When deep bites are present it is advisable to use a bite plate to open the bite prior to bonding the lower anteriors. Headgear forces against the upper molars eventually broke *Theta tNorth #Appco
D&Angles, Dental Health Products, Inc., Niagra Falls, Pacific Dental, Inc., Kirkland, Wash. Mfg. Co., Mini-Cold Station, Chula Vista, Calif.
N. Y.
Volume 14
Number
Table
Direct
2
I. Number
of brackets
bonded
to 2,218
Bondmor No.
teeth
and percentage
I liquid-powder
bonded
% success
bonding
oj’metal
of posttreatment Bondmor No. bonded
brackets
201
success
II paste-paste % success
Maxilla:
First molars Second premolars First premolars Canines Lateral incisors Central incisors
46 98 82 174 180 180
76.6 77.3 87.0 94.2 95. I 96.4
38 94 98 156 150 152
78.6 77.3 89.8 93.0 94.4 95.3
22 58 80 60 88 104
73.4 75.0 78.2 88.0 90.5 89.6
18 40 52 60 94 94
70.0 72.3 80.4 87. I 89.2 88.8
Mandible:
Second molars First molars Second premolars First premolars Canines Incisors
the bonds, due to the peel and cleavage forces. However, high-pull headgear with hooks soldered anteriorly on round or edgewise arches did not tend to break the adhesive joints. The attachments primarily used had mesh backings. Their curvatures were adapted to the teeth prior to bonding. Perforated brackets were also employed and were not as satisfactory clinically. The new mesh/pad brackets seem quite promising and bond well, since they are well adapted to the curvature of the teeth, which enhances bonding.*? With experience, direct bonded brackets can be placed fairly accurately by sighting the middle third of the crown or using a measuring gauge. When tying edgewise brackets with ligatures it was found that using lighter ligature wire-O.007 inch (0.178 mm.) instead of 0.010 inch (0.254 mm.)-bracket failure was decreased. Excessive force in tying and pinning arch wires should be avoided. Although I used pretorqued brackets, 1 prefer the ARTS torquing arch for the edgewise technique and the von der Heydts torquing auxiliary for the Begg technique. Uprighting of maxillary canines seemed slower for bonded attachments than banded canines in the Begg technique. Corrections of rotations are more difficult to accomplish with bonded brackets than with bands. RESULTS Table I indicates the results obtained after treatment and removal of brackets. There seems to be no significant difference in the success rate between the liquid-powder and paste-paste materials; additionally, the results are comparable to Zachrisson’s.’ The success rate was the highest in the maxillary anterior teeth and decreased progressively posteriorly. The mandibular anteriors had the second highest percentage of success. The posterior teeth had the lowest success rate because of difficulty in maintaining dryness in these areas and excessive forces exerted by appliances and mastication. *American Orthodontics, Sheboygan, tOrmco Corp., Glendora, Calif. $Atlanta Orthodontics, Atlanta, Ga. IRocky Mountain, Denver, Colo.
Wis
202
Am. J. Orthod. AuguFt 1978
Newmutt
Fig. 4. Scanning electron photomicrograph. enamel. Note peaks, valley, and microporosities extensive bonding surface. (x 10,000.)
Surface-treated (50 per cent phosphoric acid) tooth where adhesive can flow and polymerize, creating
DEBONDING
Removal of brackets was accomplished by squeezing the mesial-distal comers of the bracket at the adhesive joint and twisting (peel and cleavage forces) gently with a ligature cutter. The adhesive remnants were removed with a sickle-scaler, band remover (ETM* No. 348 or Rocky Mountain No. 347), and/or Cavitroni machine. Pumicing with a prophylaxis paste was sufficient to bring the teeth back to their normal appearance”, I1 (Figs. 4 to 6). For experimental purposes, attachments were bonded with Protect0 and Concise. It was more difficult to remove adhesive remnants from the tooth surfaces with these adhe*ETM, Monrovia, Calif. tL. D. Caulk Co., Milford,
Del
Volume 14 Number 2
Direct bonding of metal brackets
203
Fig. 5. Scanning electron photomicrograph. Bondmor I adhesive remnant on mesh surface after removal of metal bracket. Note tags of adhesive that flowed into tooth surface microporosities. (x 2,000.)
sives than with Bondmor I and II. This may be attributable to several factors: Bondmor I and II are less chemically cross-linked, have less filler percentagewise, and are less viscous. The fillers in Concise* and Protectot contribute to hardness, abrasion resistance and tensile and compressive strengths; however, these mechanical properties make debonding more difficult and apparently do not contribute to bond strength. Bondmor I and II were formulated to promote bonding and to concomitantly allow for ease of removal of the adhesive remnants, because of the possibility of damaging the enamel surface, which can be viewed in scanning electron photomicrographs.12* l3 The possibility of “latent” erosion’* before and after debonding is a factor that requires additional study and is difficult to predict prior to bonding. *3M tLee
Co., St. Paul, Pharmaceuticals,
Minn. South
El Monte.
Calif.
204
Am. J. Orthod. Augwt 1978
Newman
Fig. 6. Scanning Bondmor pattern.
electron photomicrograph I adhesive remnant with a scaler, This is the stage prior to prophylaxis
ORAL
HYGIENE
showing tooth surface immediately after the Cavitron, and light pumicing. Note characteristic and acquisition of the salivary tooth pellicle.
removal of prism end (22,000.)
At every visit an explorer was inserted and “wiped” between the interproximal spaces of the patient’s incisors to dislodge bacterial plaque and prevent caries. Toothbrush instruction with a fluoride tooth paste was stressed and fluoride oral rinse prescriptions were given to the patients. Surprisingly, little caries was found interproximally. Premolars and molars that were difficult to bond because of inaccessibility, excessive salivation, severe rotations, and poor patient cooperation were banded with Cementex” (containing 5 per cent sodium monofluorophosphate). l5 Decalcifications were rarely seen after removal of bands when Cementex was used. *General
Orthodontic
Labs.,
West
Orange,
N. J
Vo6ume 74 Number 2
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205
Severely rotated and short-crowned mandibular anterior teeth were difficult to bond and interproximal bonding occasionally occurred. Dental floss or an interproximal tooth stripper was helpful in opening contacts. In several individual children there was a high percentage of loose attachments, confirming previous in vitro and in vivo studies that there was a great deal of individual variation. A controlled research survey conducted by the West Orange Health Department, in which children in a fluoride-rinsing group rinsed daily with a 0.1 per cent solution of sodium fluoride at night after toothbrushing, showed a 35 per cent decrease in caries. Consequently, a fluoride rinse should be used daily by all patients after bonding and banding.* Although not shown in the Table I statistics, it was clinically noted that there were fewer decalcifications in patients who had the primer applied to the tooth surfaces prior to application of the adhesive than when the adhesive alone was used. Furthermore, bond strength was increased and removal of adhesive remnants was facilitated.16 The increase in bond strength when the primer was used was confirmed in in vitro tests as well. l’, I8 SUMMARY
A posttreatment evaluation of 180 orthodontically treated patients having 2,218 bonded brackets was made with a sealant and liquid-powder and paste-paste, chemically polymerized composite materials. All brackets were bonded by the author employing edgewise, Begg, and Begg ChunHoon brackets. By lightly tying 0.007 (0.178 mm.) inch ligatures and lightly pinning, less force was exerted on the brackets, tending to prolong the adhesive bond. Esthetics and gingival conditions were improved by using minimal amounts of adhesive material. The use of the primer (sealant) tended to enhance adhesion and decrease decalcifications. The liquid-powder success percentages were similar to the paste-paste composite material and compared favorably to Zachrisson’s findings. The data from Table I indicate that clinically, the greatest percentage of bonding success is primarily in the six maxillary anterior teeth and secondarily in the six mandibular teeth and premolars. Bonding of the first molars that may require headgear, lingual arches, lingual buttons, and cleats, or bumpers is not practical in many cases over a 2- to 3-year treatment period. Peel and cleavage forces are created by these appliances tending to break the adhesive bonds. Consequently, from a practical, clinical standpoint, the author prefers to band the posterior teeth with an anticariogenic composite cement such as Cementex. Severely rotated and partially erupted second premolars are difficult to bond, since excessive salivation and poor visibility limit posterior bonding with direct bonding techniques. Reduction of dental caries and decalcifications can be accomplished with bonded attachments supplemented by sealants, fluoride mouth rinses. and the use of fluoride gels on the bonded teeth during treatment. Debonding with Bondmor I and II is facilitated by having a lower percentage of fillers, less hardness, tensile and compressive strengths, and less cross-linking than most commercial composite adhesives. *Phos-Flur,
Hoyt
Laboratories,
Needham
Heights,
Mass,
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Newwxm
REFERENCES 1. Zachrisson. B. V.: A posttreatment evaluation of direct bonding in orthodontics, AM. J. ORTHOD. 71: 173-189, 1977. 2. Brandt, S., Servosa, J. M., and Wolfson, J.: Practical methods of bonding, direct and indirect, J. Clin. Orthod. 9: 6 10-636, 1975. 3. Bowen, R. L.: Use of epoxy resin in restorative material, J. Dent. Res. 35: 360-369, 1956. 4. Newman, G. V.: Adhesion and orthodontic plastic attachments, AM. J. ORTHOD. 56: 583, 1969. 5. Mulie, R. M., and Hoeve, A. T.: The limitations of tooth movement within the symphysis, studied with laminagraphy and standardized occlusal films, J. Clin. Orthod. 10: 899, 1976. 6. Newman, G. V.: A biomechanical analysis of the Begg light arch wire technique, AM. J. ORTHOD. 10: 737, 1963. 7. Newman, G. V.: Current status of bonding attachments, J. Clin. Orthod. 7: 425-449, 1973. 8. Newman, G. V.: Cementex: An insoluble caries preventive cement, J. Clin. Orthod. 8: 524-527, 1974. 9. Sadowsky, P. L., and Retief, D. H.: A comparative study of some dental cements used in orthodontics, Angle Orthod. 46: I7 I - 18 I, 1976. IO. Newman, G. V., and Facq, J. M.: The effects of adhesive systems on tooth surfaces, AM. J. ORTHOD. 5% 67-75, 1971. 1 I. Silverstone, L. M.: Fissure sealants: The susceptibility to dissolution of acid-etched and subsequently abraded enamel in vitro, Caries Res. 11: 46-S I, 1977. 12. Caspersen, I.: Residual acrylic adhesive after removal of plastic orthodontic brackets: A scanning electron microscopic study, AM. J. ORTHOD. 71: 637-650, 1977. 13. Gwinnett, A. J., and Gorelick: Microscopic evaluation of enamel after debonding: clinical application, AM. J. ORTHOD. 71: 651-665, 1977. 14. Mannerberg, F.: Appearance of tooth surface as observed in shadowed replicas, Odont. Revy. Supp. 6: I IO, 1960. 15. Newman, G. V., and Cimasoni, G.: In viva uptake of fluoride by enamel from an adhesive system, Angle Orthod. 41: 236-240, 1971. 16. Newman, G. V.: Bonding plastic attachments to tooth enamel, J. New Jersey Dent. Sot. 35: 346-358, 1964. 17. Mitchem, J. C., and Turner, L. R.: The retentive strength of acid etched retained resins, J. Am. Dent. Assoc. 89: I 107. I I IO, 1974. 18. Meurman, J. H., and Nevaste, M.: The intermediate effect of low-viscous fissure sealants on the retention of resin restorative in vitro, Proc. Finn. Dent. Sot. 71: 96-101, 1975. 659 Eagle
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