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THE READERS' CORNER

Topics this month include indirect vs. direct bonding and use of Invisalign appliances.

1. Do you use indirect bonding? What do youfind are the advantages and disadvantages ofindirect bonding?

Only 12% of the respondents indicated thatthey used indirect bonding. Accordingly, most ofthe clinicians believed the disadvantages of thesystem outweighed the advantages. The drawbacksmentioned were that improper seating ofthe indirect tray requires a complete redoing ofthe procedure and possibly a reappointing of thepatient, that the amount of composite flashinvolves extra chairtime to remove, and that excessivelaboratory time is needed for constructionof the indirect setup.

Advantages listed by the respondents whoused indirect bonding were more precise bracketplacement, reduced chairtime and stress in bonding,and the ability to delegate the procedure.

Typical comments included:

  • "The advantage is more precision in bracketplacement. The disadvantage is the possibility ofa disaster if the transfer trays are not seatedfully."
  • "The disadvantages of increased lab costs andsetup time outweigh the advantage of improvedindirect bracket placement. For instance, I stillhave to deal with bonding adhesive thickness, thecomposite flash is less controllable and thereforetakes more chairtime to clean up, and 1st-orderbend adjustments still must be made."
  • "Within my treatment modalities, indirectbonding takes more ancillary time, lab time,chairtime, and patient visits than direct bonding."
  • "The occasional bracket failure is when indirectbonding defeats its purpose."
  • How does indirect bonding compare to directbonding in terms of cost-effectiveness?

    There was a distinct difference of opinionbetween those who used indirect bonding andthose who preferred direct bonding. The indirectbonding advocates believed that reduced chairtimeand delegation of the procedure made itcost-effective. Conversely, the other orthodontistsbelieved that all the steps required for theimpression, cast construction, placement ofbrackets, construction of the transfer tray, andseating of the tray made the technique moreexpensive.

    Some representative comments:

  • "Indirect bonding is more time-consuming andexpensive, but worth it."
  • "When it works well, indirect bonding probablyis more cost-effective for me because it minimizesthe need to reposition brackets and/orplace detail bends. I find the bond strengths areusually equal, or sometimes better, than withdirect bonding."
  • "Considering the time and procedures necessarywith indirect bonding, I find direct bondingto be more cost-effective."
  • If you who use indirect bonding, how do youmake the setups? What transfer tray material doyou use? What bonding material do you prefer?

    Nearly all of the respondents constructedthe indirect setups and transfer trays in theiroffices without using commercial laboratories.The preferred tray material was either a silicone-basedimpression material or a vacuum-formedplastic. Only one respondent used a hot-glue gun.No one reported using a hybrid tray (a siliconecore with a vacuum-formed shell).

    The adhesive preferred by a majority of theclinicians was a two-paste, chemically cured system,but this was closely followed by a light-curedsystem. No respondents used a one-step,chemically cured system or a heat-cured/chemicallycured combination.

    What are the advantages and disadvantages ofyour indirect bonding system compared to othersyou have tried?

    In general, when clinicians changed theirindirect bonding systems, it was because they feltthat a new protocol would be more clinically efficientthan the one it replaced. The primary considerationcited was the best seating of the transfertray with the least chance for distortion orexcessive composite flash.

    Pertinent remarks included:

  • "I have control over bracket position. I personallydo all final positioning. I prefer to use siliconetray material because it's easy to apply, easyto remove, and seats accurately. I have used indirectbonding for 23 years continuously."
  • "Since I have used a light-cured system, thereis less flash. I used to get unfilled bonding resinin my self-ligating bracket bases, which couldprevent opening and closing of the ligating gate.Also, I can seat the transfer tray without timeconstraints and make sure it is seated properlybefore curing."
  • "I use the system exactly as Dr. Anoop Sondhiteaches. The vacuum-formed plastic trays arevery thin and easy to work with. Clinically, thechange in the viscosity of the two-part systemmakes the clinical bonding very accurate andvery rapid. No composite setting takes place untilthe trays are completely seated, and then the setis very rapid--approximately 30 seconds for thepreliminary set."
  • "I am unable to band the first molars on thesame visit because separators move teeth slightlyand the indirect trays don't fit precisely."
  • 2. What percentage of your patients are beingtreated with Invisalign appliances?

    Forty-six percent of the respondents reportedthat they had not incorporated Invisalignappliances into their practices. For the remainder,the percentage of patients treated with Invisalignvaried from .1% to 10%, with the vast majority inthe 1-3% range.

    What percentage of your patients are being treatedwith similar multistage plastic appliances?

    Another 26% of the clinicians used similar(not Invisalign) plastic appliances. The percentageof patients treated with these devices wasbetween 1% and 8%, with most respondentsusing them in 1-2% of their cases.

    What percentage of your practice's gross incomeis attributable to treatment with Invisalign orsimilar appliances?

    For the overwhelming majority, the percentageof gross income attributable to Invisalignor similar appliances ranged from less than 1% to2%. A few clinicians, however, reported percentagesof gross income as high as 6%, 10%, or18%.

    What percentage of your Invisalign cases finishon time?

    There was a wide range of answers, butmost respondents indicated that 80-95% of theirInvisalign cases finished on time. Still, more than13% reported that 50% or fewer of their casesfinished on time, and two clinicians said thatnone finished on time.

    What is the most complicated case you havetreated with Invisalign appliances?

    The most common reply was a Class I casewith moderate upper and lower crowding. A fewclinicians reported using Invisalign appliances intreatment involving lower incisor extractions,upper bicuspid extractions, or space closure, andone reported treating a four-bicuspid extractioncase with Invisalign.

    What problems have you encountered with Invisaligntreatment?

    Numerous problems were listed, the mostprevalent being the precision of final detailing.Finishing issues included residual spacing,occlusal difficulties, uncorrected rotations andintrusion, inadequate vertical control, and posterioropen bite, as well as the need to retakeimpressions for a finishing set of aligners. Otherproblems involved poor patient compliance withwearing the aligners as directed and a lack ofeffective communication with the laboratory.

    Specific comments included:

  • "There is limited finishing control. Althoughthe appliance is an excellent method for"straightening teeth", achieving functionalocclusal results, in my opinion, is pot luck, especiallyfor those whose goal is to treat to a seatedcondylar position."
  • "Occasionally aligners have stopped fitting.This is almost always due to poor cooperation,and we have to do a midcourse correction."
  • "Results at the end of aligner use do not matchthe ClinCheck diagnostic workup. This has beena recurring problem."
  • "I have problems correcting retroclinedincisors and difficult rotations. I have had to retreata few cases with conventional orthodontictreatment because the Invisalign appliance couldnot get the results that I wanted."
  • "I just feel I can do a better job with conventionalbraces. I think the technology behindInvisalign is intriguing, but I don't like to pass itsexpense along to the patient."
  • Have you treated adolescents with Invisalign? Ifso, how would you describe their cooperation?

    Of those who reported using Invisalignappliances, twice as many clinicians had treatedadolescents as had not. A distinct majority ofthose who had used the aligners in adolescentsreported that their level of cooperation was generallygood, excellent, or fair. Only two cliniciansreported poor cooperation, attributing thisto lost appliances.

    If you encounter relapse, do you restart with theappropriate appliance in the sequence?

    Seventy percent of those who usedInvisalign appliances said they would restart withthe appropriate appliance in the sequence. Someclinicians, however, reported that patients hadeither thrown away or lost all their used aligners,or that no previous aligner fit the existing archform.A typical answer was, "If the patient hasstopped wearing their aligners, we return to theappropriate aligner, if it can be found, and startagain."

    Do you charge for retreatment with Invisalign orextra Invisalign appliances?

    Two-thirds of the respondents did notcharge for retreatment or additional aligners.These clinicians usually purchased the insurancefrom the Align Corporation to cover such a contingency.Several respondents noted that a chargewould not be applied unless the retreatment weredue to the patient's negligence or lack of cooperation.Interesting individual comments were:

  • "I don't charge for retreatment because I purchasethe $50 insurance to absorb this cost ifretreatment is necessary."
  • "If the patient was compliant and the results donot match the ClinCheck, I don't feel that I canrecharge the patient. If the relapse is from lack ofretainer wear, I would charge a fee."
  • "If Invisalign does not reach my expectations,I absorb the fee for the finishing details."
  • JCO would like to thank the following contributorsto this month's column:

    Dr. Manijeh Askarieh, Washington, DC

    Dr. Bruce A. Baker, Evansville, IN

    Dr. Joel J. Beaman, Fairfield, CT

    Dr. Mark F. Bellard, Beaumont, TX

    Dr. Timothy J. Damon, Pittsford, NY

    Dr. Ralph J. De Domenico, Tampa, FL

    Dr. Keith B. Dressler, Chattanooga, TN

    Dr. Donald L. DuVall, Richmond, VA

    Dr. Carol P. Edwards, Cedartown, GA

    Dr. Rebecca A. Faunce, Palm Coast, FL

    Dr. Robert J. Gange, Windsor, CT

    Dr. Mark Hall, Miami, FL

    Dr. Robert D. Helmholdt, Fort Lauderdale, FL

    Dr. Steven J. Hoagburg, Fort Wayne, IN

    Dr. C. Joel Hodge, Ashland, OR

    Dr. James V. Martuccio, Warren, OH

    Dr. Michael T. McKee, Burlington, NC

    Dr. Paul E. Miller, Quincy, IL

    Dr. Elliott M. Moskowitz, New York, NY

    Dr. Greg C. Nalchajian, Fresno, CA

    Dr. Leon Nehmad, Northfield, NJ

    Dr. Christopher A. O?Rourke, Knoxville, TN

    Dr. J. Greg Osborne, Gardendale, AL

    Dr. Donna Panucci, South Charleston, WV

    Dr. John B. Pardini, Jr., Downingtown, PA

    Drs. Clayton T. Parks and Jason L. Schmit, Cedar Rapids, IA

    Dr. Thomas G. Peters, Los Gatos, CA

    Dr. Arnie Rozental, Toms River, NJ

    Dr. Keith T. Sellers, Charlotte, NC

    Dr. Nancy F. Shackleton, Louisville, KY

    Dr. Tony L. Skanchy, Sandy, UT

    Dr. William B. Snipes, Dalton, GA

    Dr. Lee Souweine, Jr., Bangor, ME

    Dr. M.E. Steen, DeLand, FL

    Dr. William P. Swetlik, Shawano, WI

    Drs. James W. Tinnemeyer and Thomas D. Forrest, Pittsburgh, PA

    Dr. Andrew P. Trapani, West Dundee, IL

    Dr. Howard F. Vincent, Jr., Charleston, SC

    Dr. M.A. Vorhies, Greenwood, IN

    JOHN J. SHERIDAN, DDS, MSD

    JOHN J. SHERIDAN, DDS, MSD
    Dr. Sheridan is an Associate Editor of the Journal of Clinical Orthodontics and a Professor of Orthodontics, Louisiana State University School of Dentistry, 1100 Florida Ave., New Orleans, LA 70119.

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