When to Extract

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Dr. Raphael L.

Greenfield

D.D.S., M.Sc.D.

About Dr. Greenfield

(An excerpt from Dr. Raphael L. Greenfield’s new textbook: 98.5% Nonextraction Treatment using Coordinated Arch Development)

Webster’s Dictionary1 defines “stability” as the capacity of an object to return to equilibrium or to its original position after having been displaced. As Hemley2 stated, our ultimate goal is to “establish a relationship of the teeth to each other and their supporting structures and surrounding musculature which permits them to best perform their functions and is most conducive to their continued health.” Once functioning teeth have been extracted, the dental arches lose their capacity to return to their original morphologic state. Teeth are moved into areas normally occupied by other teeth. Consequently, extensive functional adaptation must occur for the masticatory system to survive. If not, a functional disorder may occur to one or more of the three components of the system; the occlusion, the cranial mandibular articulation and/or the neuromuscular system. Since the cranium is integrated with the spinal column, introducing these new variables may also affect other systems. Also, can we regularly predict how extraction treatment will affect aesthetics, posture, mastication, degluition, respiration, speech and psyche. From the volumes of published research, it is still generally unclear how clinicians reach these critical treatment decisions.3

Prior to specializing in orthodontics, most of us spent a minimum of four years learning the goal of general dentistrythe preservation of the dentition! Countless hours were dedicated to restorative dentistry, periodontia, prosthodontia, endodontia, oral surgery, Temporomandibular Dysfunction, implantology, cosmetic dentistry, nutrition, etc. These disciplines afforded us the required knowledge to attain our treatment goals.

Why as orthodontists are we the only specialty that seeks to alter the logical morphology of the dental arches when we were taught the consequences? Does cephalometrics drive our decision to extract? Maybe we should heed Salzman4 when he stated, “the use of cephalometric standards drawn from individuals with excellent occlusion as a means of deciding treatment objectives has no scientific justification! Morphologic deviation from a mean, however large it may be, cannot per say be looked upon as a condition requiring orthodontic treatment. The only thing one can be certain about cephalic measurements is that they will vary from patient to patient. The range of variation is more important than the mean of which the so called standards are based.”

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This late mixed dentition mesocephalic male presented with blocked maxillary cuspids and a blocked mandibular left cuspid, (Images A-C,G,H). Due to the space requirements in both arches, and the necessity to preserve the cephalometric standards of a modified Steiner analysis, the decision was made to extract the maxillary 1st bicuspids and the mandibular 2nd bicuspids. In the final result, optimal function, and ideal dental esthetics were achieved, (Images D-F,I,J). Ideal facial esthetics and a radiant smile were also produced in the final result. However, 5 years post retention painted quite a different picture. The patient’s beautiful smile disappeared behind extensive counterclockwise growth – a factor not considered or predictable during diagnosis and treatment planning. This may have been avoided if the additional variables of extraction therapy had not been introduced, and more attention had been given to the transverse dimension during diagnosis.

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Consider this scenario. What if our so called “normal” standards aren’t so normal. What if during the critical stages of growth and development, allergies or disease causes an extended period of mouth breathing? Several studies have shown a strong correlation between mouth breathing and facial form, (ie./Long Face Syndrome). 5-9 If mouth breathing produces varying degrees of contracture in the dental arch, should the resultant morpholopgy still be considered within the normal range? By what standards? This may seem dogmatic to most, but with the ongoing pollution of our environment, could the above concept be far from the truth? In one 1989 study,10 an environmental economist at Brigham Young University in Provo, Utah took advantage of a labor dispute that shut down a steel mill, the major source of air pollution in the area. From the valley’s three hospitals, he collected counts of admissions for respiratory illness before, during, and after the plant shut down.

The results were striking. When the mill was in operation, admissions were 40% higher for bronchitis and 17% for pneumonia. Especially startling was the effect on preschool children; twice as many admissions for bronchitis and asthma! And let us not forget, 60% of cranial development is completed by the age of four. Also, Provo’s air was only slightly dirtier than North American Standards when the mill was operating!

So if our normal standards aren’t as normal as we choose to believe, how can we establish a proper treatment plan – especially when there is great variability in the growth of each individual and wide variation in the response of patients to the same treatment? This answer is quite simple. We must pay more attention to individual variation!

Individual Variation

Johnson11 defined individual variation best when he said, “we must at all times attempt to find the normal for the individual, and then we will then have the condition of occlusal relations which is the most effective in maintaining in its most stable form the equilibrium expressed in the life phenomena of the individual organism. It may or may not approximate the species normal. It is not an artificial creation built upon an ideal plan. It is the most perfect condition of occlusion that the nature of the tissues and the functional activities of the organism as a whole will permit.”

Thirty five years later, Brodie12presented his observations stating, “we may have precocious eruption associated with an average rate of growth, or a normal eruption associated with a slow rate of growth, both of which would lead to temporary disharmonies in the tooth-jaw ratio.”

In 1992, Thilander13discussed the complexity of the subject at the American Association of Orthodontists National Meeting when she said, “a fully developed cranium is the sum of the separate parts, in which growth is highly differentiated and occurs at different rates and in different directions.”

Spanning the entire century, it is clearly apparent that the importance of individual variation still occupies a very significant role in diagnosing and treatment planning. An example of an individualized treatment plan is this bimaxillary protrusive adolescent dentition. With a 6.7 mm. arch length deficiency, a popular computer service recommended the extraction of four 2nd premolars for this 13 year 2 month female. The photographs that follow illustrate that a successful long term stable result was achieved without extractions!

A hyrax/cervical gear tandem was used for 6 months, followed by a RMD (Removable Molar Distalizer or Cetlin Appliance), in the maxillary arch, and a Level II lip bumper in the mandibular arch. Enough space was obtained to resolve the arch length discrepancy, and eliminate the bimaxillary protrusion. A cervical gear was utilized to torque the maxillary 1st molar roots distally underneath the tipping crowns, (Images A-M). The natural arch forms “developed” in phase 1 were maintained during the fixed appliance (brackets & archwires) phase 2, (Images N,O).

In the final result, the posterior segments have been uprighted transversely and sagittally simultaneously, creating maximum intercuspation with the forces of occlusion through the long axes of the posterior teeth, (Images P-T).

By placing the teeth well within cancellous bone and within the “neutral zone” of the surrounding musculature, function has maintained the result for 7 years without any retainers, (Images U-DD).

Function is the best retainer when it can optimally perform its duties.

The following study model analysis reveals the transverse and sagittal changes that took place during the course of treatment.

Although the intercanine width lost 1.04 mm. long term from the final result, the net gain was +4.33 mm., (Images A-C). This goes against the general concensus in the literature that the intercanine dimension in the mandibular arch usually cannot be violated. However, in the CAD technique, the canines are distalized divergently into a wider dimension of the arch from the pull of the transeptal fibers. Thus they are unintentionally expanded simultaneously during distalization from the lip bumper, but remain well within cancellous bone at all times!

The transverse dimension in the bicuspid area appears to have the greatest response to the lip bumper, (Image D). However, the posterior teeth must be discluded (e.g./ maxillary bite plate), to to achieve this dramatic effect, (Images E-F).

Uprighting the posterior segments sagittally and transversely simultaneously, while controlling the vertical dimension, allows the forces of occlusion to be transmitted through the long axes of the teeth. This provided exceptional stability in the result, (Images G-I). Even with no retainers for 7 years, the 1st molars remained in their final position, (Image I). Optimum function is your best retainer!!

Note the dramatic change in the axial inclination of the 1st molars from the original malocclusion to 7 years post retention.

The arch length decreased 0.5 mm. long term.   But remember, when arches are contracted in the original malocclusion from noxious habits, there is a significant increase in the sagittal dimension.   Therefore, when the transverse dimension is recaptured, the sagittal dimension will logically decrease.   This effect is desirable to reduce the bimaxillary protrusion, and return the anterior teeth into the “neutral zone.”

Similar changes are reflected in the maxillary arch, (Images J-R).

The bimaxillary protrusion was resolved by the significant decrease in arch length.

Note that the positive changes in the mandibular arch “coordinated” with the positive changes in the maxillary arch – hence the term “Coordinated Arch Development.”

Although long term incisor position experienced significant improvement, one cannot judge the overall changes of a malocclusion by simply analyzing serial 2-dimensional radiographs.  All three dimensions must be reviewed concurrently to determine the true efficacy of a specific treatment approach.

Seven years post retention displayed a significant reduction in the profile and a beautiful radiant smile, (Images A-G).  Facial esthetics, function and periodontal health were optimized, and long term stability was achieved using the nonextraction Coordinated Arch Development approach.

We therefore may be misdiagnosing if we simply treatment plan our cases based on sagittal and vertical discrepancies such as arch length deficiencies, bimaxillary dentoalveolar protrusions, and/or high angle patterns.  No matter how sophisticated the cephalometric analysis, without incorporating the transverse dimension, the diagnosis may not reflect the true cause-effect relationships of the malocclusion. The treatment plan may only be addressing a portion of the problem.

Despite the implications of individual variations, Tweed14 in 1946 proposed that virtually all cases with a Frankfort mandibular plane angle between 28 and 35 degrees required the removal of teeth.  More than 50 years later, Little15 did a ten year post retention study on extraction vs. nonextraction cases, comparing the instability of lower incisor position. The results showed relatively equal amounts of crowding long term. He thus deduced that, “enlargement of the mandibular length in the mixed dentition phase to accommodate arch length deficiency offers no better solution (than extraction treatment).  In fact, this method of treatment may yield the poorest stability.  Patients treated early by enlargement or by “development of the arches,” as it has recently been dubbed, respond after retention as do other treated and untreated groups, and demonstrate similar changes.  The most distressing finding, is the degree of relapse noted after treatment with this (nonextraction) strategy.  In fact, patients treated by this strategy show greater relapse than other samples we have collected.  In most cases of arch enlargement or “development,” such treatment results in relapse and crowding beyond acceptable limits.  Patients and their parents should be aware of the high potential for relapse if such a plan is adopted.”  However, Woodside16 recently compared transverse changes in premolar extraction with nonextraction groups and found that intercanine width decreased three times faster in premolar extraction cases than in nonextraction cases.

Regardless, Little’s study, and the conclusions drawn are flawed.  The sample used for nonextraction treatment included patients treated by fixed edgewise appliances, active lingual arches, lip bumpers, and removable appliances.  That is similar to baking a cake that tastes horrible and blaming all the ingredients!  For the study to be valid, each method must be evaluated separately before drawing any conclusion.  Second, the method must be used properly.17  In the chapters that follow, each method utilized in the “Coordinated Arch Development” approach to nonextraction treatment will be explained in great detail. Also, long term results will be profusely illustrated to support these methods.

Maybe sagittally and/or transversely there are similarities, as implied by Little, but we must remember we are treating a three dimensional patient. Clearly, changes in one dimension will affect the other two.  To be considered valid, our future studies must evaluate the changes in all three dimensions.  We have the capabilities to do that now with the introduction of 3D scanned study models, and CBCT (cone beam computed tomography) scans.  Until these studies are commonplace, higher resolution AP and lateral cephalometric views, coupled with 3-dimensional study model scans, offer the clinician an acceptable degree of analysis, (Images A-C).

Serial cephalometric x-rays may be used to predict growth pattern but we must recognize that these patterns may change at any time due to one or more variables, (i.e./vectors, increments, duration, etc.).  The allotted time that we have to treat our patients, (about 10% of the growth cycle), may not afford us the opportunity to witness all these variables. However, it certainly paints a more vivid picture than one point in time. The CAD approach to nonextraction treatment attempts to include the pubertal growth spurt.  Although it may or may not require additional treatment time, this is a critical period where some of the greatest incremental growth and developmental changes take place. Why not use it to our advantage?  As Graber18 stated, “I am confident that with our dependence on pattern, growth, and development, we must turn to a longer period of orthodontic management in many cases.”

Lower Incisor Position

Is the position of the lower incisors the determining factor?  Certainly Tweed was an advocate of placing special emphasis on lower incisor position.19, 20  Tweed maintained that + 5º to a tangent of the lower border of the mandible was the range of normalcy, with the incisors oriented on the “ridge” of basal bone. In 1944, Speidel and Stoner21 disproved Tweed’s concepts in their study on the variation of the angle formed by the lower incisors to a tangent of the lower border of the mandible, and to the occlusal plane in normal untreated occlusions. The range was 28º for the mandibular plane and 27º for the occlusal plane. Also, in 1944, Brodie22 in a study of 104 untreated cases determined that, “the axial inclination of the lower incisors is an individual characteristic which shows a great range of variability in any sample of normal and abnormal.”

Cephalometric Analysis

As stated earlier, the efficacy of cephalometric analysis lies in its ability to measure changes resulting from growth and/or orthodontic treatment. Projecting a three-dimensional object onto a one-dimensional surface sometimes makes it difficult to separate the two. Even with its inherent limitations, cephalometrics can clarify the anatomical basis of the malocclusion. This is certainly an important adjunct in establishing our treatment objectives. But as Ackerman and Profitt23 stated, “knowledge of the key factors required for successful treatment comes only as a treatment itself proceeds.”

Baumrind24 added, “the clinician must be in a position to see and optimally respond to the continuously altering state of the patient as treatment proceeds…..growth prediction is not accurate enough to address individual variation in the relatively short time we treat our patients.”  The bottom line is, cephalometric analysis is only one component of our diagostic criteria – not the determining factor!

Muscle Reeducation

Coordinated Arch Development,” as the title implies, is coordinated with individual growth and development. The soft tissue envelope is also reeducated to accept morphological changes in individual arch forms. As Thilander13 indicated, “ a stable post treatment result is hard to expect if malocclusions caused by muscular or other soft tissue dysfunction has been only morphologically corrected without any alteration in the muscle behavior.”  Positions of the teeth in the arch are significantly affected by the constantly changing soft tissue environment. Protracting posterior teeth into a different soft tissue environment without muscle reeducation may result in a narrower archform – forcing the incisors to flare or crowd, (Image A).

Occlusal Stability

Nonextraction enhances occlusal stability by providing and positioning a maximum number of dental unites to ideally perform their intended functions.  Distributing occlusal forces to a maximum number of teeth, over the life span of an individual enhances their longevity.

First molars must be situated well within cancellous bone.  Their normal position in the arch should not be disturbed.  Attempts to protract the molars into a narrower portion of the arch may lead to serious consequences.  First, the molar will resist mesial movement resulting in loss of anterior anchorage and compromised facial esthetics.  Second, extraction sites may tend to reopen long term.  Third, expansion of mesially positioned first molars may result in loss of periodontal support.  Thus, the clinician should first distalize molars into a wider dimension of cancellous bone prior to expansion, or expand and distalize simultaneously in equal proportions.

The requirements of occlusal stability are as follows:

  1. Maximum and ideal intercuspation
    1. Proper axial inclinations
    2. Roots well within cancellous bone
  2. Vertical control (occlusal plane)
    1. Overbite i harmony with the slope of the eminence (ie/posterior guidance in harmony with anterior guidance)
  3. Neuromuscular balance
    1. Absence of soft tissue dysfunction
    2. Elimination of noxious habits
  4. Functional Equilibrium
    1. Compatibility of functional forces transmitted through articulating buccal and lingual incline plane relationships through varying degrees and ranges of mandibular movements. Failure to do so will place the teeth at a mechanical disadvantage – producing excessive horizontal torquing forces resulting in long term instability.

Occlusal stability should be regarded as a dynamic rather than static interrelationship between facial structures. Therefore, if we refer to instability as strictly dentoalveolar changes following orthodontic intervention, we have not focused on the entire problem.

Arch Form

To know when the form of a dental arch is normal for a particular individual is a difficult problem to resolve. Hrdlicka25 suggested that, “there s no such thing in existence, in any race that we know of, as one single normal dental arch; that in every race and even under most normal conditions, we find a variety of arches which must be considered as normal arches; and it will be the duty, it seems, of the dental surgeon of the future to pay close attention to these facts because they cannot but have a direct bearing on the intelligent treatment of his patients.” Graber18,almost a half century later, reaffirmed the above sentiment when he stated, “with all the studies that we have on growth and development, we still have a long way to go before we can routinely predict ultimate arch size with precision.”

Mathematical models have also been utilized to approximate arch forms.26, 27 However, individuality still to this day remains an issue in orthodontics.

Arch forms must also be in harmony with root apices as well as crowns.  Anterior root apices will converge in a narrow tapering arch form, (Image A).  Using the same archwire reshaped to a broader arch form, the root apices will diverge – enhancing periodontal health and functional stability, (Image B).  It would appear that a broader arch form may be more conducive to an optimal periodontal environment than a narrower arch form.

Functionally generated lateral jaw movements appear to be related to the arrangement of cusps as well as condyles.28 The implication being improperly oriented cusps could lead to interferences.

Comparing a narrower extraction arch form with a broader nonextraction arch form in two ten year post retention cases, one can readily see the heavier contact of the right canines during a right lateral working excursion in the extraction case, (Image A).  The lighter contact of the same excursion in the nonextraction case also recruits the lateral and central incisor as well, (Image B).

Equally important is that a narrower arch form increases the sagittal dimension of the arch.  This increase in arch length requirement may not be conducive to long term stability since Morrees’29,30 studies indicated that this dimension significantly decreased with age.

From a clinical standpoint, how does one determine individual arch forms? Obviously, there are many factors that ultimately determine the arch form. However we must realize that we cannot restrict our thoughts to hard tissue. The soft tissue environment clearly has an effect on arch form.  If we reeducate the soft tissue environment as well as correct the dentoalveolar morphology, we may be getting closer to individualized arch forms. Therefore, the original form can be used as a reference, but not an end point.

Different growth patterns have a decisive influence on the spacial relationships of the teeth within the dentoalveolar complex and the direction of tooth eruption.31, 32  For these reasons, I purposely leave approximately 2 mm. of interdental space for each arch in the final result to allow the teeth to “settle” into their desired positions based upon the hard and soft tissue requirements that are unique to that patient.

I do not believe in permanent retention because it restricts the normal physiological changes of aging. Certainly the morphogenesis of teeth, the development of the dentition, growth of the craniofacial skeleton, and functional aspects of the soft tissue complex must be considered. Nothing in nature is permanent except death of the organism.  As Mershon stated in 1926, “we can put the teeth where we think they belong, but nature will eventually place them where they actually belong.” We certainly will need more data specific for racial and facial types, growth, appliance and technique, age at initiation of orthodontic treatment, extraction vs. nonextraction, and neuromuscular balance, before we can better define a specific arch form.  In the absence of noxious habits, neuromuscular problems, or aberrations in growth, I normally retain my cases until the eruption or extraction of the third molars.

Function is the best retainer we have, and failure to realize this will only postpone the inevitable.

When Do We Extract?

Certainly there is a place for extraction in orthodontics.  You cannot treat every case using a nonextraction approach. If that were true, there would hardly be a circumstance for diagnosis.  That said, extraction should be viewed only as a last resort – when all other methods cannot satisfy our treatment goals.  Our primary focus is the 1st molar position.  If one chooses an extraction approach, every effort must be made to avoid protracting the molar into the extraction site.  If a significant amount of extraction space remains mesial to the 1st molar (i.e./ ≥20%), after satisfying the alignment and profile requirements, one should expect a high degree of long term instability. To summarize our criteria for extraction, the following is presented;

Requirements for Extraction

  1. ≥ 8 mm. of crowding in the mandibular arch.
  2. A severe profile requirement is present.
    1. Bimaxillary dentoalveolar protrusion
  3. 1st molar position must not be disturbed after satisfying requirements #1 & #2 above.
  4. High angle pattern
  5. All teeth are upright sagittally and transversely in the original malocclusion.
  6. Incisor anglulation is periodontally compromised, (i.e./ severe protrusion).
  7. Molars are initially in a Class I relationship.
  8. Noncompliant patient

When all or most of these criteria are present, we could then entertain the possibility of extracting permanent dental units.

In the latter part of his illustrious career, even Tweed33 appeared to have softened his stance on extraction therapy when he stated in 1963, “…and in the not too distant future, the vast majority of orthodontic treatment will be carried out during the mixed dentitionperiod of growth and development, prior to the difficult age of adolescence.”

 

Bibliography

  1. Miriam Webster, Inc.:  Webster’s Ninth New Collegiate Dictionary, 1985
  2. Hemley, S.:  Occlusion – The Orthodontic Point Of View, Journal Of Dental Medicine, Vol. 5:59, 1950
  3. Duterloo, H.S.:  Extraction Vs. Nonextraction: 8-18. Sid Publisher, 1995
  4. Salzman, J.A.:  Limitations Of Roentgenograhic Cephalometrics, Amer. J. Orthod. 52:331-352
  5. Quinn, G.W.:  Airway Interference And Its Effect Upon The Growth And Development Of The Face, Jaws, Dentition And Associated Parts:  North Carolina Dental Journal 1978; 60:  28-31
  6. McNamara, J.A., Jr.:  influence of respiratory pattern on craniofacial growth.  Angle orthod. 1981; 51:  269-299
  7. Bushey, R.S.:  Alterations In Certain Anatomical Relations Accompanying The Change From Oral To Nasal Breathing;  Mesis. University Of Illinois, Chicago, 1965
  8. Harold, E.P.;  Chierici, G, Varqervik, K:  Experiments On The Development Of Dental Malocclusions. Amer. J. Orthod. 1972:  61: 38-44
  9. Linder – Aronson, S; Woodside, D.:  The Channelization Of Upper And Lower Anterior Face Heights Compared To Population Standards In Males Between Ages 6-20 Years.  Eur. J. Orthod. 1979; 1:  25-40
  10. Is Our Air Clean Enough; Consumer Reports, P. 36, August, 1997
  11. Johnson, A. Leroy:  The Individual Normal – The Problem Of Orthodontia; Int. J. Of Orthod. And Oral Sjurg., C.V. Mosby Co., 5:  306-327, 1919
  12. Brodie, A.G.:  Read Before The Extraction Panel Of The Meeting Of The American Assoc. Of Orthod., Chicago, April 26, 1944 This One Is A
  13. Thilander, Birgit:  Read Before The Amer. Assoc. Of Orthod., 1992
  14. Tweed, C.H.:  Frankfort – Mandibular Plane Angle In Orthodontic Diagnosis, Classification, Treatment Planning And Prognosis, Amer. J. Orthod. And Oral Surg., 32: 175-221. 1946
  15. Little, R.M.:  Mandibular And Arch Length Increase During The Mixed Dentition:  Postention Evaluation Of Stability And Relapse.  Amer. J. Orthod. And Dentofacial Orthopedics, May 1990
  16. Woodside, D.G., Rossouw, P.E., Shearer,D: Postretention mandibular incisor stability after premolar serial extractions. Seminars in Orthodontics, (5):3, Pages 181-190, September 1999
  17. Cetlin, N, Ten Hoeve, A.:  Nonextraction Treatment, Jour. Clin. Orthod. 17:  396-413, 1983
  18. Graber, T.M.:  Postmortems In Post Treatment Adjustments, Amer. J. Orthod. 52: 331-352
  19. Tweed, C.H,:  The Appliance Of The Principles Of The Edgewise Arch In The Treatment Of Class II Division I Malocclusion, Angle Orthod, 6: 198-208, 255-257, 1936
  20. Tweed, C.H,:  The Appliance Of The Principles Of The Edgewise Arch In The Treatment Of Malocclusion, Angle Orthod, 11: 567, 1941
  21. Spiedel And Stoner:  Variation Of Mandibular Incisor Axis In “Normal Occlusion,” Amer. J. Orthod., And Oral Surg., 30: 536-542, 1944
  22. Brodie, A.G.:  Read Before The Extraction Panel Of The Meeting Of The American Assoc. Of Orthod. Chicago, April 26, 1944
  23. Ackerman, J.L., Profit, W.R.:  Treatment Response As An Aid In Diagnosis And Treatment Planning.   Amer. J. Orthod.  57:  490-496, 1970
  24. Baumrind, S.:  Clinical Judgment Versus Prediction Towards A New Paradigm For Orthodontic Research, In:  Science And Clinical Judgment In Orthodontics.  Vig, P.S. And Ribbens, K.A. Ed. (Pp.149-162), Craniofacial Growth Series. Mon. 19 CHGD, Univ. Of Michigan, Ann Arbor, 1986
  25. Hrdlicka, A.:  Anthorpometry, Philadelphia, Westor Inst. Of Anatomy And Biology, 1920
  26. Brader, A.C.:  Dental Arch Form Related With Intraoral Forces:  Pr=C. Amer. J. Ortho. 61: 541-561, 1972
  27. Neilaus, L.C.:  A Computerized Analysis Of Human Dental Arch Forms As Compared To The Catenary Curve.  Philadelphia, 1968, Temple University, Master’s Thesis.
  28. Jordan, R.E., Abrams, L. Kraus, B.S.:  Dental Anatomy And Occlusion, 2nd Ed. St. Louis: Mosby Books, 1992, 243-249
  29. Moorrees, C.F.A. And Chada, J.M.:  Available Space For The Incisors During Dental Development – A Growth Study Based On Physiological Age.  Angle Orthod.  35: 12-22, 1965
  30. Moorrees, C.F.A. And Reed, R.B.:  Changes In Dental Arch Dimensions Expressed On The Basis Of Tooth Eruption As A Measure Of Biologic Age. J. Dent. Research. 44:  129-141, 1965
  31. Mitanz, H. Sato, K.:  Comparison Of Mandibular Growth And Other Variables During Puberty.  Angle Orthod. 1992, 62:  217-222
  32. Nanda, R.S. , Ghosh, J.  Longitudinal Growth Changes In The Sagittal Relationship Of Maxilla And Mandible.  Amer. J. Orthod. Dentofac. Othop. 1995, 107: 79-90
  33. Tweed, C.H.:  Treatment Planning And Therapy In The Mixed Dentition, Am. J. Orthod. 49:  900, 1963

“Excellent clinical presentation with long term results”Dr. Thomas GraberFormer Editor-In-Chief,World Journal of Orthodontics 

“An outstanding clinician”Dr. Norman Cetlin
“Must read – will transform your approach to orthodontics”Dr. Rohit SachdevaCo Founder & Chief Clinical OfficerOrametrix, Inc. (SureSmile) 


Using more than 7,000 photographs and illustrations, and 1100 pages, Dr. Greenfield reveals the principles and methods necessary to properly diagnose and treat the most difficult nonextraction cases with the utmost confidence. If properly timed, the clinician will possess the knowledge to treat greater than 90% of his cases with a time tested (60 years), nonextraction approach.

Dr. Greenfield has combined his clinical expertise obtained from treating more than 10,000 nonextraction cases in 30 years of private practice using the Coordinated Arch Development® philosophy & technique, along with his extensive research and exposure to hundreds of Dr. Norman Cetlin’s successfully treated nonextraction cases more than 25 years out of retention.

The textbook includes a reference library of 48 nonextraction cases with flowcharts, emphasizing the versatility, stability, and optimal dental and facial esthetics of this philosophy.

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