JCO Interviews Robert M. Ricketts

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DR. BRANDT: All right, Rick, I want to change the subject now and discuss your article in the January 1969 Angle Orthodontist in which you listed twenty-four points which were generally accepted tenets in orthodontics at one time. You now find every one of these unacceptable and I believe that a discussion of these points may reflect much of your treatment philosophy and your office philosophy and be of extreme interest to our readers. Let us begin with point one. You do not accept the belief that the growth pattern is established by the first year and thereafter is stable. Are you suggesting that a child at eight years of age with a short ramus and a steep mandibular plane angle may change that pattern significantly by age fourteen or thereabouts?

DR. RICKETTS: Let's say I have seen it change but I think that the element here is one of interpretation of what is meant by stability. This is the challenging part-- the interpretation of the word stable. What do you really mean by stability? There seems to be a strong tendency for proportions in faces to remain essentially constant in natural growth. This is the whole thesis of forecasting. But, I believe that we have something else to consider. We talk very loosely about cranial growth as a function of the neurocranium, which is the brain case. The brain and stem usually have developed by the time the mixed dentition starts. It is not by accident that a child begins to attend school at age six; this is the time usually when the brain has matured. But, from then on, his soma or his body and skeleton and face continue to grow. This is the reason we have what is called a 'hafting zone' for the face, or the division between the neural skeleton and the splanchnoskeleton. At this particular time, some growth patterns start to express themselves in different directions. The stability which was present in the first five or six years of life no longer is revealed as the basicranial structures are employed for superimposing. The direction may become altered as some develop facial length, while others grow more in facial depth.

Certain of these growth expressions seem to be related to the overall type of body growth of the individual. For instance while you do see it, it is a rather rare experience to see a long, narrow face on a short, squat person. By the same token, how often have you observed a very tall individual with a short heavy neck and a square face Therefore, a part of the facial development must tend to be an expression of the height increase of the whole individual. Don't forget that the mandible is a bony member of the face which is suspended in musculature alone. Even the ligaments can't hold the mandible in place if the muscles are lost. For some reason, orthodontists started thinking of the face as having its own isolated directives and forgot that it is subject to its environment in any way. You may say that patterns going in a direction continuously are still stable changes in that one consistent direction. This is not to take issue with men who held this thought of constancy, but I cannot accept the fact that the face is not subject to environment. You and I both have seen different reactions to the same therapy. Kinesiology cannot be left out and kinesiologic phenomenon is subject to neurologic and psychologic input.

DR. BRANDT: Question number two. Yog do not accept that the rest position is constant and unchangeable. How can the rest position be influenced?

DR. RICKETTS: If you will go back in the literature, you will find that the hypothesis that was set forth by Thompson was that the mandible was a function of the postural system and therefore was independent of the influence of the teeth, that the normal mandible closed from the rest position in an upward and forward position through a distance of about two to three millimeters and that position was not influenced by the presence or absence of teeth. Now, the rest position of the mandible is a position that is dictated by musculature and, it must be remembered that the mandible is located in a kinetic chain and occupies its position in a muscular sling. This kinetic chain starts from in back, through the supporting and cantilevering of the head; it encircles the head and comes down through the muscles of mastication and the lower jaw and is therefore suspended together with the hyoid bone. Brodie has described this apparatus repeatedly in many of his physiologic talks about this mechanism. The other factor, though, that is of importance here is to realize that the mandible is influenced by two functions in a vegetative system. One is food preparation or mastication and perhaps deglutition and the other is respiration. Now, if the airway is obstructed by the presence of adenoids or tonsils or allergies, there tends to be an adaptation forward to help nature open up the airway so that the child can breathe with greater facility. If he doesn't breathe through his mouth he must breathe through his nose, either of which means that the mandible must be brought forward to open up the airway passages in back. We have seen, therefore, as patients have grown and as lymphoid tissue is involuted, a relative proportional change in rest position as the respiratory apparatus goes through a modification. Number two, we have also seen changes in the position of the mandible without orthodontic treatment following the removal of tonsils and adenoids, and we've even seen a change in the habitual posture of the hyoid bone and the tongue from a low position to one that is up in the mouth almost immediately, at least within the healing process of the tonsillectomy and adenoidectomy. This is not always the case, but nevertheless we have observed these changes with a high enough consistency to expect changes to occur rather than not to expect them, especially when the position of the mandible is incorrect to begin with.

Now, in addition to that, the mandible is positioned in the interest of economy because the mandible will be held into a compensatory position so that it can go either way for the number of functions that it must perform. For instance, if the patient has a deep bite, he may reach forward for the function of incision. If a wide overjet is present, instead of holding the mandible fully retracted at physiologic rest, he will position it somewhere into a compensatory neutral position forward. He can therefore move it forward to incise and to speak or he can move it backward in a convenient manner rather than having to move it the full distance.

So you see, we've introduced a number of factors. It must be remembered that mandibular posture is responsive to the entire neurologic pool which brings into significance all the proprioceptive mechanisms that influence the kinetic chain as these are functioning. As long as these conditions remain stable, there is a likelihood that the mandibular posture-- rest postion-- will remain unchanged. But, given these changes, then, in sequence changes tend to occur.

DR. BRANDT: I am going to cover points three and four together. You do not accept that orthodontics is limited to alveolar bone nor the idea that the maxilla is fixed and cannot be altered.

DR. RICKETTS: Here is a question for which I simply cannot understand the resistance. I suppose that my initial questioning of these axioms goes back to our days of treatment of cleft palate at the University of Illinois in 1949. We were treating many cleft patients on the deciduous dentition by widening the arch with the old Coffin type of appliance and we saw the permanent teeth moving together with the segments of the bone. From the frontal cephalometric projection, it was noted that the permanent crypts and bone moved in the transverse plane. We thought perhaps this was due to the fact that the palate already was split in these cleft palate individuals. But then we saw the same thing occurring in patients who possessed hard scar tissue between these elements or in effect a fixed maxilla. There began to be a question as to whether or not this statement that orthodontics is limited to alveolar bone was appropriate . Theoretically, the permanent canines were completely above the level of the palatal plane and certainly this was not alveolar bone. This was up in the body of the maxilla. If these skeletal members were moved apart, we were making changes beyond the alveolus primarily in the maxillary denture.

We also recognized that in ordinary orthodontic treatment nothing seemed to change beyond the root apices. This goes back to a presentation that I made in the Tweed Society in 1950 when Ben Herzberg asked a question from the floor regarding changes with treatment, based on our studies at that particular time. I answered that I thought, on the basis of our evidence, that we were limited to the level of the palatal plane in the upper and the mandible in the lower, and that as far as I was concerned, based on what I saw, we were still limited to that. In retrospect now, we believe that the reason for that observation was because we were using only light intermaxillary elastics. We recognized at that time that there were alterations in the vertical position of the mandible as a result of traction of intermaxillary elastics, and extrusion of the posterior teeth, but we passed these off as minor adjustments which were temporary alterations in function and which would be recovered with natural growth. At that time these observations were passed off as influences which would not affect the basic bone proper.

To continue the story, however, in 1952 (the year I went to California) a thesis was sent to me by Dr. Watson, who was a graduate student from St. Louis University. He had observed a change in the angulation of the palatal plane from the SN plane with the pull of cervical extraoral traction. Instead of accepting the changes he described, I'm afraid I discounted them as his inability to make correct tracings or locating nasion. This study sowed the seed for the future work which showed that alteration could indeed occur as a result of orthodontic-orthopedic forces.

By 1960, however, we had conducted a controlled study of growth and treatment changes. By comparing, over a period of three years, 100 non-treated patients to 100 patients treated with extraoral traction, we found maxillary alteration to be quite conclusive. We now believe that extraoral traction in the magnitude and the duration of orthopedic force affects maxillary alteration and can indeed be expected and changes can be forecast.

DR. BRANDT: The next idea that you do not accept is that the growth of the mandible is not influenced by teeth. I'd like to ask you how is the growth of the mandible influenced by teeth?

DR. RICKETTS: There are two parts to the question and this has to do with whether or not you're going to call the behavioral characteristics of the mandible a part of the growth pattern of the mandible, because the growth pattern of the mandible is reflected in two categories. One is its relationship to the calvarium and to the rest of the skull since, as we mentioned before, the mandible is a suspended member. If there is something that, through the meeting of the teeth, influences its posture relative to the face, then indeed you have altered its growth pattern, as we understand patterns of the mandible, because a part of the mandibular characteristics is the manner in which it is canted into the skull. For instance, you can observe high mandibular plane angles with square mandibles. You can also see high mandibular plane angles with obtuse mandibles. The mandibular plane angle is not directly determined by the form of the mandible specifically. Tuverson in 1962 at the University of Southern California, pointed out that the Frankfort mandibular plane angle was not due to the total influence of the form of the mandible alone but was a combination of its forms plus the manner in which it was cocked into the face.

So you may find either square mandibles with high mandibular planes or obtuse, open gonial angles with high mandibular planes. These two, while they'll give you identical readings of mandibular plane angles, are as different as day and night. This means if the teeth of either arch are extruded, if props are placed in the back of the mouth, or a wedge is placed in the occlusal plane, the mandible is thus prevented from being closed. If this wedge of teeth becomes a permanent kind of a situation, then the extrusion of the teeth themselves indeed effected this mandibular posture.

It could be argued semantically as to whether or not this is really a true alteration of the mandible. But there is a phenomenon that is occurring which is not well known and not well recognized but for which we now have pretty good evidence. By headgear traction on the upper

molar or extrusion of the teeth of both arches by intermaxillary elastics, the mandible may be stopped in an open position by the teeth. As a compensatory action, the whole head changes its tilt on its cervical axis. The facial height increases anteriorly in the anterior part of the kinetic chain and it is non-reversible by ordinary function. It is therefore a permanent alteration of the posturing of the head on the cervical axis as a part of the phenomenon that was introduced by the teeth. This then becomes an alteration of not only the mandible but of the entire kinetic chain and the entire head.

Furthermore, as stated in my publication of 1966 where we talked about the influence of occlusion on the temporomandibular joint, you will see that there was a strong case built for the fact that occlusal trauma of the right magnitude could break down the condyle head. If this phenomenon occurs during the growth stages, it is my hypothesis at this time that pathologic occlusion can develop in the child. Factors of bruxism and other problems in the early ages, even in the deciduous dentition, can alter the growth pattern of the mandible by its influence on the condyle head. This is a phenomenon that I can confirm with numerous clinical patient records. This means that there is a pathologic influence in the growth of the mandible, due quite possibly to the malocclusion.

DR. BRANDT: Point six has been quite controversial. You do not agree with the statement that molars cannot be moved distally. Can you move maxillary and mandibular molars distally? And how far?

DR. RICKETTS: You will see that due to some of the recent techniques we have developed, particularly for the computer, we now have yardsticks enabling us to evaluate the upper molar completely independently from the maxilla. We measure it from the pterygoid vertical plane which is a true distal landmark or a plane of reference which gets away from the maxilla or the upper jaw complex altogether. Normally, and this occurs with a high degree of regularity, the upper molar on average will move forward very slightly more than a millimeter a year in a normal growth pattern. If in fact you have only held the molar where it is, you have prevented this yearly increment of one millimeter movement. So, if you held it back for two years you have subtracted two millimeters from where it would have been. But it is not this inhibition to which I am referring. In fact we have records of cases in which we have moved the molar backward toward the pterygoid plate almost a full centimeter in three years' time. This means that we actually have altered its position thirteen millimeters from where it would have been, which is more than the width of the molar. The argument says, but you didn't permanently move it back. Well, of course not. The patient doesn't die. When you release it, it's going to express its normal tendency to come forward again, but not to the place of its previous location. It will then go on and perhaps reflect its normal 1 mm a year, or a little more. If you don't have bicuspids in front of it to hold it back, then it will drift back into a forward position, but usually it will not if you have the whole denture in position. Thus we have permanently moved the upper molar backward. The key is cooperation. Now, what about the lower molar? One of the factors which has been learned very recently from Bjork's work is that we can no longer trust the mandibular plane for reference and it becomes a problem in the mandible as to what the lower is related to in determining its behavior. All the references that have been traditional as reference lines in the mandible have been shot down by the findings of Bjork. Since 1950 it has

been my position that pogonion has been a stable reference. Either I was a good guesser some years ago or I had a correct sense of the development of the mandible. I based my conclusions on some earlier work of DuBrul who studied phylogenetic mandibular development and authored "The Adaptive Chin". I was blessed with a good intellectual experience with Dr. DuBrul who was the head of the anatomy department and an anthropologist. So, I conjectured that pogonion was the stable point and that as buttons developed on the chin, what was indeed happening was that the mandibular denture was receding on its denture base rather than apposition occurring on the bony chin. This was my position 'way back in 1950 and it was based on the earlier comparative anatomy studies. This became a part of the development of my belief, around 1950-1952, in the A-pogonion plane as a relationship for the lower incisor. Since that time Bjork has confirmed a stable pogonion and has shown that the mandible in many instances actually resorbs on its lower border with normal growth. Much of the change we frequently were calling eruption or change of teeth from the mandibular plane was, in fact, nothing more than a resorption of the lower border of the mandible. This meant that we had to reexamine a great many of the erupting characteristics of the lower molar and its mesiodistal change because we could no longer accept practically any of the work that had been done previously on a longitudinal basis. Any study which employed the mandibular plane or the lower border as the plane of reference had to be questioned.

One of the best keys to determine whether or not a lower molar moved backward is to see whether or not there is a space developed between it and the second deciduous molar. You have an excellent clinical guide already built in and we have records of several cases in which the lower molar can also be moved distally. One of the best proofs of this phenomenon is the use of a "bumper" which is nothing more than molar bands on the lower molars stopping a .045" wire with a polyethylene tube around the labial bar as this arch is bumped up against the lower lip. Now, in the beginning we used this as a technique to "reverse the flow", the tide of the lower lip working under the upper incisor against the lower incisor. We placed this into a position where the lower lip would be pushed forward so that it would extend around the labial surface of the upper incisors and reverse the influence of the lip on the upper incisors. Well, lo and behold, after we had used these for a while in some individuals we found that sometimes up to three and four millimeters of space would open up between the first molar and the second deciduous molar. We checked these changes cephalometrically and we could corroborate the fact that this indeed was not the second deciduous molar moving forward, but that the lower lip was pushing back the molars. Nothing more than the lip pressure alone in a constant fashion was moving the molars backward. Because it was a constant force, it was more effective than Class III elastics or an extraoral headgear operating against the lower molars. Thus, the first molar can be moved backward if given a continuous force of a sufficiently high magnitude.

DR. BRANDT: When you move these lower molars back, are they apt just to tip or will they go back bodily?

DR. RICKETTS: It can be moved bodily but will usually tip, depending on the mechanics. Instead of using a bumper, we frequently now will apply a force against the lower incisors to intrude them and move them downward against the lower lip. In this instance, the four lower

incisors are placed against the lower lip and, in some individuals, the lip and labial bone will then cause the molar and buccal teeth to be moved backward. Even the utility wire, which is an .016" blue Elgiloy square wire with a buccal vertical step, is strong enough to move the lower molar backward.

[show_img]330-jco-img-2.jpg[/show_img]Because we are trying also to intrude the lower incisor as well as bring it forward, we introduce a tip back bend against the lower molar. It operates to tip the molar as well as to push it backward, but a bumper will produce direct bodily movement without tipping. Furthermore, we have had some cleft palate cases that were so hard to treat that I ended up locking the mandibular and maxillary teeth together as you would treat a fracture case. It is in effect just an orthopedic forcing of the maxillary segment forward into a position with the mandible. In a few of these situations, I have not only moved the lower molar backward but also we have indications, from intraoral and cephalometric x-rays, that the usual pattern of new bone laid down has been positively reversed. New bone was observed in intraoral x-ray all across the anterior side of the tooth just as you usually see on the distal side during space closure of extraction cases.

Furthermore, to extend this into even a deeper context, we have new references for evaluating the molar movement. A corpus-axis plane is established which is a line from the geographic center of the ramus to pogonion as a reference. We now have found strong suggestion in some individuals that, with just natural growth, the lower molar is moving posteriorly with development all on its own, with no orthodontic treatment at all.

DR. BRANDT: Now, let's wind up this discussion about molar movement with Point seven. You do not agree that the first molar always moves forward to take up the leeway of the second deciduous molar.

DR. RICKETTS: Yes, because in many individuals, particularly when you put headgear on the upper arch, the lower molar will stay there positively without moving anywhere. As the second deciduous molar is lost, the space is taken up by distal drift of the premolars into that space. This is a beautiful phenomenon and is a part of our conviction that interceptive treatment is really the way to go in most of these patients because you don't have to mechanically move the teeth. All you are doing is holding and inviting nature to take over. This is one of the reasons for my feeling that I can treat four times the number of patients ("in the chair" time) that I once could treat. Now I am taking advantage of known qualities and quantities.

DR. BRANDT: Now, Number 8. You do not agree that the intercanine width cannot be permanently increased. When and how do you decide that the intercanine width can be increased ? What are the criteria ?

DR. RICKETTS: This is an interesting phenomenon and the one, of all of these under present discussion, about which I am the most unsure. I recall some conversations with Hayes Nance some years ago. He got up at a meeting and challenged this ability to expand cuspids. He'd never seen a canine which had been moved wider than three millimeters and observed it to hold. This is a very strong statement. He believed, as I recall, that even when you took out premolars and moved the cuspids back, you had to respect canine width increase. In a way, this simply means to me that there must be a muscular limitation in this area. The canine teeth do not have their own particular restricted position and we can see such a wide variety in arch form and types of arches, sometimes almost completely independent of the structural morphology, or the bony morphology of the face. This has led me to believe that the real factors which determine the arch width are probably connected in some way with the interangular dimension of the soft tissue of the mouth (one corner of the mouth to the other). The complex of the caninus-triangularis muscle mass in this area may have something to do with this phenomenon.

Not only do I believe that canine width can be increased, but my experience has shown that in some individuals you don't even have to put an orthodontic appliance directly on the lower arch to

witness an increase. If, by virtue of the treatment for a Class II Division 1 case, you have placed a headgear on the upper arch and have retracted the upper incisors without banding, and the upper canines have been expanded without even an appliance being placed on them, the treatment influences the lower arch in a direct manner also. You may see widening of the intercanine width in the lower arch without ever treating that arch directly. This means that the key to the determination of this is understanding the behavior of the soft tissue in function. We haven't studied well the corner complex of the mouth.

Another factor of recent concern is the behavior of the lower arch when palatal splitting is done. Rapid expansion seems to be here to stay and has been studied extensively by Haas, Wirtz, Iverson and others. Dr. Ruel W. Bench, my partner in our office, has been studying this particular phenomenon in detail with frontal laminagraphy. Many orthodontists now are paying attention to this treatment. Some of the lower arches are seen to improve with the palatal split in the mixed dentition to the extent that patients never need any orthodontic treatment in the lower arch. Some unquestionably would have been four-bicuspid extraction cases with full hookups at a later age.