Deep and Open Bites and Maturation Treatment Planning

Fifty-eight percent of the respondents believed the bites would stay open, but 38% felt the stability of bite opening was too difficult to predict. Only two respondents claimed that opened bites do not stay open. A typical comment was:

• "Bites usually stay ideal if incisal torque is slightly exaggerated and overbite/overjet is close to ideal. Relapse usually occurs when these cri­teria are not established."

To what do you attribute the relapse of a correct­ed deep bite?

The majority believed that musculoskeletal factors were involved. This response, however, was often qualified by factors including poor fin­ishing procedures and lack of retainer wear. Also mentioned, but to a much lesser degree, were misdiagnosis, not opening the bite early enough in treatment, and inadequate overcorrection. Comments included:

• "I interpret relapse of a deep bite in mesofacial skeletal patterns as being an instance where treat­ment was compromised, but maintenance of a corrected deep bite in patients with brachyfacial skeletal patterns is simply not as predictable."

What technique do you use for closing open bites?

Again, most respondents used a combina­tion of techniques rather than a single method. By far the most popular procedure (63%) was the use of vertical anterior elastics. More often than not, this was coupled with some sort of habit appliance (tongue crib or spikes) and with swal­lowing and tongue exercises. Many clinicians (18%) said they placed stepbends in the arch­wires or bonded the incisors more gingivally. Posterior highpull headgear and biteplanes were favored by some. Eight percent believed extrac­tions were advisable to help close open bites. Also mentioned were Bioprogressive sectional archwires, the Woodside molar impactor, and transpalatal bars. Two respondents believed the most effective tool might be prayer.

Do the closed bites usually stay closed?

The key word in this question is "usually". The majority of respondents (58%) believed that it's difficult to predict whether a closed bite will stay closed. Twenty one percent thought it would stay closed, but 19% believed it would not. There were many comments indicating that closing an open bite was the treatment procedure most sus­ceptible to relapse.

To what do you attribute the relapse of a correct­ed open bite?

Most respondents ascribed relapse to a combination of tongue and swallowing patterns, closely allied with deviant growth and with mus­cle, airway, and skeletal problems. A few respon­dents implicated poor diagnosis, poor patient cooperation, or not retaining the correction long enough. An interesting comment was:

• "It takes time to alter a neuromusculature pat­tern. We usually get the open bite resolved at the end of treatment and then debond. The correction has only been in place for a few months, while this complex pretreatment problem has been evi­dent for years. To expect the bite to be altered, and remain stable under these conditions, is somewhat naive."

What technique do you use to distalize molars bilaterally? Unilaterally?

Most clinicians listed a combination of techniques. By far the most popular distalization device was headgear, complemented by, in decreasing order of priority, Class II elastics and open-coil springs, the Hilgers Pendulum Appli­ance, and the Distal Jet appliance. Less frequent­ly mentioned were Wilson modular devices, Jasper Jumpers, lip bumpers, Hawleys with jack­screws, and Gianelly distalization mechanics.

The same techniques were generally used to distalize molars unilaterally. Again, the most popular methods were headgear, in conjunction with open-coil springs, the Hilgers Pendulum Appliance, or the Jones Jig.

Do you distalize mandibular molars, and how?

Fewer than 5% of the respondents said they distalized mandibular molars frequently. The majority (65%) did so occasionally, while the remainder reported that they never distalized mandibular molars.

The device most commonly used was the lip bumper. Equal percentages either used open-­coil springs (with or without supporting Class II elastics or headgear) or uprighted the molars through archwire manipulation, such as tipbacks, amplified by coil springs. One response:

• "I am hesitant to distalize lower molars because it causes the end-on or Class II molar relationship to worsen. Then I have to compen­sate for this situation with other mechanics."

Do you use a visualized treatment objective (VTO)?

Sixty-two percent of the respondents never used a VTO, 19% used it routinely, and 19% used it occasionally.

Individual comments were:

• "A VTO is an educated guess and only really helpful in long-face vertical growth patterns. How many orthodontists 10-20 years in practice are really using VTOs in treatment planning? Who has the time?"
• "I routinely use a VTO. I feel I can better antic­ipate growth direction, but I'm reluctant to pre­dict it and will not rely on a VTO to validate an amount of growth."

Can the amount and direction of growth be pre­dicted, and how?

Nearly twice as many clinicians thought the amount and direction of growth could not be pre­dicted as thought it could. Many of the respon­dents believed the direction of growth may be more predictable than the amount.

The most common method of determining growth parameters was the use of a computer data system such as Zero Base or Quick Ceph. This was closely followed by resemblance to par­ents and siblings, and by presuming a continua­tion of the existing growth pattern. Smaller per­centages used the Ricketts analysis or mandibu­lar plane and Y-axis recordings, or simply relied on experience.

Is the pubertal growth spurt an important con­sideration in your treatment plans?

Two-thirds of the clinicians said it was an important factor. A few indicated that the puber­tal growth spurt was a particular consideration in Class III patients.

Is it important to know the stage of skeletal mat­uration in a growing patient? Why or why not?

Three-fourths of the respondents believed skeletal maturation was an important considera­tion. Their reasoning was that there was a win­dow of opportunity in which to take advantage of the possibility of altering growth potential. Many clinicians mentioned that the stage of skeletal maturation was more important in Class III and potential surgery cases, while 10% of the sample thought it more pertinent in Class II cases. Those who thought skeletal maturation was unimpor­tant in treatment planning tended to believe that "you can't do much about it" or "it's just a guess".

More specific comments included:

• "Growth modification efforts result in only minimal skeletal changes. Most change is dental. Patients and parents need to understand what small changes can be effected, and clinicians need to face up to our limitations in this area."
• "If you believe in growth modification, it's cru­cial to the outcome--also timing of treatment. Early treatment may be undone by the resump­tion of an unfavorable posttreatment growth pat­tern."

Are wrist x-rays valid measurements of the skele­tal maturity of the jaws?

Fifty-two percent thought wrist x-rays were valid, 38% felt they were not, and the remainder were unsure. A typical remark:

• "It's another contributing factor in diagnosis, but I rarely rely on them except in the timing of surgical cases."

Do you rely on cervical vertebrae to determine skeletal maturity?

Fully 95% of the clinicians did not use the cervical vertebrae to assess skeletal maturity. There was little elaboration on this question, although one orthodontist mentioned that such an assessment eliminated the need for an extra radi­ograph, since the cervical vertebrae can be eval­uated from the lateral cephalometric film.

Two of the respondents who valued the analysis of cervical vertebrae quoted the litera­ture to justify their opinion: Lamparski's Milo Hellman award-winning thesis (Skeletal age assessment utilizing cervical vertebrae, Univer­sity of Pittsburgh, 1972), and Hassel and Far­man's article (Skeletal maturation evaluation using cervical vertebrae, Am. J. Orthod. 107:58-­66, 1995).

What are the effects of post-pubertal growth on treatment?

About half of the respondents directed their focus toward Class III cases. This was distantly followed by the effect on the stability of finished cases. There were more than a few responses indicating that post-pubertal growth was more of a concern in males than in females. An interest­ing comment:

• "Don't treat on opinion or guesswork, treat to the specifics of the case at the time. If post­-pubertal growth severely affects the finished case, then it may have to be retreated, but this is practically impossible to predict. If post-treat­ment growth causes some incisor malalignment, then a simple strip-and-align touchup usually resolves the problem."

JCO would like to thank the following contribu­tors to this month's column:
Dr. Bruce A. Baker, Evansville, IN
Drs. Ronald S. Branoff and James G. Gordon, Pikesville, MD
Dr. Paul M. Broadwater, Salt Lake City, UT
Dr. George E. Cantu, Austin, TX
Dr. Morton Cohen, Jenkintown, PA
Dr. William A. Cole, Margaretville, NY
Dr. John A. Colgan, Paducah, KY
Dr. L. David Curtis, Tempe, AZ
Dr. James R. Dee, Jr., Munhall, PA
Dr. P. Jack Feller, Rock Springs, WY
Dr. Albert T. Foy, Jr., Montgomery, AL
Dr. Gerald M. Francati, St. Petersburg, FL
Dr. Barry J. Glaser, Cortlandt Manor, NY
Dr. Jo E. Hansen, Lee's Summit, MO
Dr. Waldo B. Harshberger, Frederick, MD
Dr. Richard B. Hirsch, Tampa, FL
Dr. G.W. Hubbard, Stephenville, TX
Dr. Alan W. Kaplin, Franklin Park, IL
Dr. Kenneth Kaplin, Arlington Heights, IL
Dr. James R. Karpac, Dublin, OH
Dr. M.C. Kastrop, Billings, MT
Dr. Robert A. Kay, Marshfield, WI
Dr. Elizabeth M. Kellogg, Rochester, MN
Dr. Brian P. Loftus, Williamsport, PA
Dr. Arnold J. Malerman, Dresher, PA
Dr. Susan B. McBeth, Rogers, AR
Dr. M.R. McCorkle, Jr., Roanoke, VA
Drs. Robert W. McMinn and William R. LeDoux, Bay St. Louis, MS
Dr. Edward A. Myers, Middletown, NY
Dr. George L. Nadler, Tucson, AZ
Dr. Roger C. Nettune, Basking Ridge, NJ
Dr. Casey O'Conor, North Ridgeville, OH
Dr. Charles T. Pavlick, Jr., York, PA
Dr. Richard A. Perkins, Iowa City, IA
Dr. Phillip B. Powell, Knoxville, TN
Dr. Barry Raphael, Clifton, NJ
Dr. E.G. Righellis, Oakland, CA
Dr. S. Everett Rushing, Jackson, MS
Dr. David L. Skibell, Houston, TX
Dr. Shelley A. Tretter, Cincinnati, OH
Dr. Jeffrey W. Vecere, Cape May Court House, NJ
Dr. Stanley J. Wolfe, West Haven, CT