SINCE 1971 EMPOWERING DOCTORS AND STAFFS TO ATTAIN GREATER SUCCESS THROUGH EDUCATION AND KNOWLEDGE
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SINCE 1971 EMPOWERING DOCTORS AND STAFFS TO ATTAIN GREATER SUCCESS THROUGH EDUCATION AND KNOWLEDGE |
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Two
of the most important advancements in modern orthodontics were the development
of the Straight Wire Appliance by Dr. Larry Andrews and the recent popularity of
early treatment. However, the full
advantages of Straight Wire technique were not realized until the introduction
of bonded brackets in the mid-seventies. Bonding
made the accurate placement of brackets faster and less labor-intensive.
It also improved the predictability of treatment plans, thereby reducing
the need for wire bending. The net
result has been a dramatic improvement in the overall efficiency of orthodontic
treatment. Recent advancements such
as thermal NiTi wires have further improved the productivity of clinicians who
use Straight Wire brackets. Since
the inception of direct bonding, composite resins have been the most widely used
adhesives for orthodontic bonding procedures.
Their impact on improving the efficiency of orthodontic treatment is
undeniable. Yet despite their
widespread use, they possess an inherent “Achilles Heel.”
Their major shortcoming is the series of technique-sensitive steps
required to maintain a completely dry field.
If the enamel bonding surfaces are even inadvertently contaminated with
moisture (e.g., a mouth-breathing patient), successful adhesion to the tooth is
likely to be compromised. Additionally,
the regimen for protecting the teeth from moisture contamination, in many
instances, creates stress on clinician, the staff, and the patient.
Our experience was that after etching, rinsing, and drying the teeth, the
assistant would place a primer. At
this point, the auxiliary had the unenviable job of keeping a squirming patient
from contaminating the teeth while waiting for the arrival of the
bracket-placing dentist. Depending
on the particular patient and the level of activity in the office, bonding with
resin adhesive systems is a potentially “high-stress” procedure. A
relatively recent advancement in orthodontic bonding has been the introduction
of resin modified glass ionomer orthodontic adhesives, Fuji Ortho LC
(light-cured), and Fuji Ortho (self-cured) by GC America.
Many practitioners had already been accustomed to using glass ionomer
materials (both conventional and resin modified) for dental cementation and
restorative procedures. Favorable
characteristics of these materials include self-adhesion to tooth structure and
the ability to bond to teeth in the presence of moisture.
Additionally, their fluoride releasing ability is significantly greater
than that of “fluoride-releasing” composites.1
It has been demonstrated that the fluoride released from glass ionomer
materials has been sufficient both to inhibit demineralization and to promote
remineralization of tooth structure adjacent to glass ionomer restorations.2
Moreover, the fluoride level and subsequent release of fluoride from
these materials increases when they are exposed to fluoride ions from external
sources.3 The sources for this “recharge” can be fluoridated
drinking water, dentifrices, mouth washes etc. Based
on an elementary understanding of glass ionomers and on the manufacturer’s
claims about the benefits of the resin modified glass ionomer adhesives, the
potential advantages of these materials in orthodontic bonding situations were
intriguing. The prospect of bonding
in the presence of moisture without the need for a sealant or a bonding agent
afforded the possibility of bonding a case more quickly and with less stress on
the clinician, the auxiliaries, and the patient.
The claim that the adhesives were easier to remove and clean up at
debonding (through desiccation) than existing adhesives suggested that the
debonding procedure could be accomplished more quickly.
Additionally, the idea that the fluoride release inhibited rather than
promoted decalcification appeared to be a significant advantage. For
many of us, the financial aspect of general orthodontics is an area of concern.
We wish to be compensated fairly for the expense and for time, we
invested obtaining our orthodontic education.
My CE lecture courses emphasize improving efficiency through the
delegation of duties to auxiliaries. Since
incorporating the resin modified glass ionomer adhesives into the practice more
than two years ago, I began immediately seeking ways to utilize its reported
advantages to improve our efficiency. One of these advantages (bonding in a wet field) has improved
our ability to work simultaneously on multiple orthodontic patients.
Since there is no need to place a primer after conditioning the teeth and
inasmuch as a moist environment enhances the bond, the auxiliaries are able to
work more quickly. The resin modified glass ionomer adhesives have dramatically
improved our efficiency in treating orthodontic patients.
We have increased the number of patients we treat, and at the same time,
we have reduced our level of stress. The
ability to increase the delegation of duties has made orthodontics a significant
profit center in the practice. Whereas
many of the tasks involved in bonding with composites can be delegated to
auxiliaries, patient-control procedures, as previously discussed, sometimes
create stress in a busy practice. We
initially used the resin modified glass ionomer adhesives strictly for bonding
brackets and bands. Today we use
these materials not only for brackets and bands (including surgically exposed
impacted teeth), but also for bonding Rapid Palatal Expanders, as direct
occlusal temporary splints, and for bonding lingual retainers.
They have greatly improved our overall efficiency with both the Straight
Wire appliance and early treatment. Their
ability to perform effectively in the presence of moisture has eliminated the
need for the stressful, time-consuming moisture-control activities that were
once a necessary part of all of our bonding procedures. As a result, we have less technique-sensitive, “high
pressure” procedures to perform. We
consistently bond cases more quickly than we did with composite resin adhesives.
Quite simply, we have increased our earning potential without increasing
overhead. Bracket PlacementIn
the course of practicing and/or teaching orthodontics, there have been numerous
occasions in which I was faced with explaining to parents, at case completion,
why their child would now have decalcification lesions on perfectly straightened
teeth. Despite the fact that we
have always been careful to document poor oral hygiene, there have invariably
been a few patients who have “fallen through the cracks.”
In these situations, we always explained that the child’s poor brushing
caused the decalcification. However,
even though we have been able to document and rationalize to the parents that
the result was the child’s fault, case-completion in this type of scenario has
always been an unpleasant experience for the patient, the parents, and the
clinician. Unlike
the specialist, the general dentist might continue treating the results of the
decalcification and continue seeing the patient for many years into the future. Our practice currently treats the children of children that
we treated in the past. We use the
resin modified glass ionomer adhesives knowing that regardless of the extent of
the patient’s noncompliance, we will not be faced with explaining to parents
why their “perfect child” has developed ugly spots on the teeth.
Unquestionably, all of us providing orthodontic treatment value the
referral that comes via observation of a completed patient.
Anterior teeth that have been scarred by poor oral hygiene will most
likely rule out the possibility of a referral, despite a perfect occlusal
result. It therefore behooves us to
use bonding materials that will augment our efforts to create “perfect
smiles.” We
have developed a technique that allows us to maximize the number of brackets we
can place safely with one capsule. Our
initial experience with encapsulated Fuji Ortho LC was that only a limited
number of brackets could be placed with each capsule, thereby making it a
relatively expensive adhesive. Although
the material is ultimately light-activated, its self-curing mechanism can limit
the adhesive’s working time. The
potential result is that the practitioner will not be able to use all the
material in the capsule. It should
be noted that once the material has begun its self-curing process (the
“glossy” appearance has disappeared), its ability to bond to enamel becomes
dramatically decreased. It
therefore should not be used when its appearance becomes “dull.” The
technique first developed to extend
the working time was simply to refrigerate the
capsules. Refrigeration allowed us
to place brackets on half of an arch. We
then discovered that if we expressed all the material onto a frozen glass slab
and applied the adhesive to the bonding surfaces of the brackets with a Dycal
type of instrument, we were able to place an entire arch. To prevent possible moisture condensation on the slab, a
piece of paper mixing pad is placed over the glass.
This procedure has proven to be a winner! We consistently place a full arch of brackets without any
sign of the material setting up on its own. The
following procedure is recommended for efficient light-cured bracket placement: After
pumicing, the teeth are treated with 10% polyacrylic acid (GC Ortho Conditioner)
for 20 seconds. The teeth are
rinsed and kept moist. Using a
Dycal instrument, the assistant places just enough adhesive on the bonding
surface of the bracket to provide a slight excess.
Next, the doctor places the bracket, cleans the
excess with a scaler, and then “tacks” (light cures) the adhesive for
10 seconds. After all the brackets
in the arch have been placed, the assistant completes
the light-curing (40 seconds per bracket).
As an aside, our efficiency in bracket placement improved noticeably when
the assistants mastered the technique of placing the
proper amount of adhesive on the bonding surfaces of the brackets.
We have virtually eliminated the time and effort involved in removing
excess adhesive immediately after bracket placement. Bonded Appliance PlacementEarly
treatment is recognized as a crucial aspect of modern orthodontic treatment. Rondeau recently wrote that general and pediatric dentists
are in a unique position to be experts in this phase of orthodontics.4
Perhaps the most important and versatile orthopedic appliance for the
first phase of early treatment is the bonded Rapid Palatal Expander (RPE).
It is extremely useful in the following situations: Correction
of tooth size/ arch width discrepancies Maxillary
development in Class II skeletal problems with retrognathic mandibles Class
III treatment with the Protraction headgear Posterior
and anterior crossbites Dr.
Jim McNamara is a strong proponent of using this appliance.
His research has shown that the bonded acrylic appliance is extremely
useful in treating cases with high mandibular plane angles and in closing
anterior open bites.5 Placement
of the bonded RPE has commonly utilized composite resins as the bonding
material. Although composites have
a proven record of accomplishment, a dry field is necessary to ensure that the
bonded teeth remain isolated from oral fluids.
In more than twenty years of using this appliance, maintaining a dry
field at best has been an elusive goal. The
classic early mixed patient who requires the bonded RPE often has some form of
airway problem. This patient is the
least likely to enjoy having his or her mouth open for a long period of time
while the maxillary teeth are etched and sealed prior to placement of the
appliance. Although many expanders
are successfully placed with composites, a certain tension exists during these
procedures for the clinician, the assistant, and of course the patient. For
the past two years, we have used the resin modified glass ionomer adhesives for
bonding acrylic RPE’s. Upon
removal and under magnified examination, the maxillary teeth have always
appeared to be in excellent condition. In
several cases, the duration of treatment exceeded nine months.
In most of these longer-term cases, the teeth visually have looked better
then they did before appliance placement. When
we bonded RPE’s with composite adhesives, I occasionally found myself in the
most unfortunate position of having to restore permanent teeth following RPE
removal. An improper seal at
placement and subsequent leakage, at times, caused carious lesions, generally on
first molars. Depending on the
severity of the decay, the restorations ranged from sealants to large amalgam or
composite restorations. Decay
or decalcification issues notwithstanding, the procedure for bonding RPE‘s
with composite resins can be stressful. Since
switching to the resin modified glass ionomer (more than 100 appliances placed
and debonded), placement has become a much more relaxed procedure. When the clinician and the staff develop confidence in the
principle that not only should the teeth not be dry, but in fact, they must be
moist, the procedure becomes much easier for all involved.
We no longer need to make certain that our patients took their
antisialogoge. There
are a few important differences between bonding acrylic RPE’s with composites
and resin modified glass ionomers. Although
the Fuji Ortho adhesives bond easily to enamel, they will not bond, as
composites will, to the inside of acrylic appliances; they must be retained
mechanically. The bonding surfaces
of the RPE’s are micro-etched and retention holes are placed with a round bur.
After pumicing and plaque removal, the bonding surfaces of the enamel are
conditioned for 20 seconds. To
facilitate removal of the appliance, petroleum jelly is placed on the occlusal
surfaces of the teeth. Both
Fuji Ortho (self-cured) and Fuji Ortho LC (light-cured) are available.
I recommend using the light-cured version for the first ten appliances
and then switching to the self-cured product.
The light-cured material offers a longer working time, thereby allowing
beginners more time to clean up the excess material immediately after placement.
When the practice develops confidence in the placement and clean-up
procedures, it becomes more efficient to switch to the self-cured product.
For both materials, a clear acrylic is mandatory to monitor any possible
leakage. No loss of seal has been
observed since we switched to the resin modified glass ionomer materials.
Although the manufacturer claims that final strength is not achieved for
24 hours, immediate activation of the appliance has not been a problem.
Parents are instructed in the use of a key to turn the screw immediately
following insertion of the RPE. Activation
of the appliance begins at bedtime the same night. Temporary SplintsTemporary
splints are a useful adjunct for efficient orthodontics.
They are used both to treat TMD symptoms that develop in the course of
treatment and as an aid to correct anterior crossbites.
They can also be used in vertical development in deep bite cases.6
Fuji Ortho LC is the material of choice for these applications.
It is easy to place and it is a safe substance to occlude against natural
teeth. The continual fluoride
release provides protection to the tooth structure that is being covered, very
much like a fluoride-releasing sealant. Our
most common application is a vertical opening build up on the lower first
molars. The occlusal surfaces are pumiced and then conditioned for
twenty seconds. After thoroughly
rinsing away the conditioner, “puddles” of water are removed with a
moistened cotton pellet. The enamel
bonding surfaces are kept moist. The
adhesive is injected on the occlusal surfaces to an approximate height of 2mm.
Following light-activation, the material is equilibrated and then
polished. This technique is useful
both for opening the bite for lower bracket placement and for passive eruption
of the second molars. It is also
useful for building up the lingual surfaces of the upper incisors to create a
“tripodding” effect. Likewise,
we use it on lower second deciduous molars to stimulate eruption of the
permanent first molars. Additionally,
build-ups in upper permanent first bicuspid are helpful in controlling and
treating TMD problems. Fixed Lingual RetainersThe
mandibular arch is generally retained with a fixed retainer bar that is bonded
on lingual surfaces of the lower anterior teeth.
This retainer has metal pads bonded to the cuspids and composite pads on
the incisors. Fuji Ortho LC is used
as the bonding adhesive. Inasmuch
as the retainer is expected to be in place for several years after bracket
removal, the adhesive is a good “insurance policy” against decalcification
or decay. The bonding procedure
involves scaling and pumicing the lingual surfaces of the teeth.
The conditioner is placed for twenty seconds and then thoroughly rinsed
away. The adhesive is placed on the
retainer and held in place with dental floss while the material is light-cured. Prior
to the availability of Fuji, we had always used composite resin adhesives to
bond lingual retainers. Although
the bonding procedure is not particularly difficult, the fact that we need not
worry about maintaining a dry field is certainly an advantage.
Furthermore, we have not noticed any increase in bond failures since we
switched to the resin modified glass ionomer.
Considering its ease of use and its ability to inhibit enamel
demineralization,7 the practitioner using fixed lingual retention
should strongly consider the benefits of the resin modified glass ionomer
adhesives for long term use. After
using many different types of orthodontic adhesives, I am convinced that we are
indeed close to having the ideal product. By
consistently preventing decalcification, we are satisfying the dictum of not
harming our patients with the procedures we use to straighten their teeth.
Additionally, we are maximizing the efficient use of auxiliaries, which
has increased productivity and earnings. References
1. Rasmussen
TE, Froerer JJ, Hollis RA, Christensen RP. Long term fluoride release from
compomers and flowable resins. J Dent Res 1997;76:241. 2. Donly
KJ. Enamel and dentin demineralization inhibition of fluoride-releasing
materials. Am J Dent 1994;7:275-8. 3. Wistrom
DW, Diaz-Arnold AM, Swift, Jr. E. Fluoride release/uptake of glass ionomer
restoratives. J Dent Res 1995;74:107. 4. Rondeau
B. Early treatment in mixed dentition, J Gen Orthod 1998;10:9-20. 5.
McNamara JA. Orthodontic and orthopedic treatment in the mixed dentition,
Needham Press 1993. 6. Carter
RN. Glass ionomer orthodontic splints J Clinical Orthod 1996;30(2):106-9. 7. Vorhies AB, Donly KJ, Staley RN, Wefel JS. Demineralization adjacent to orthodontic brackets bonded with hybrid glass ionomer cements: An in vitro study. Am J Orthod Dentofac Orthop 1999;114:668-74.
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