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Cleidocranial dysplasia – the Jerusalem Approach: part 3

Published: November 2013

Bulletin #26 November 2013

Cleidocranial dysplasia – the Jerusalem Approach: part 3


In part 1 of this short series on the treatment of cleidocranial dysplasia (CCD), which was presented in the September 2013 Bulletin #25 on this website, early orthopedic treatment for the protraction of the maxilla, with the use of a face mask, was discussed and its place in the timing of treatment defined. In the October 2013 Bulletin #26, the need for a two-stage approach for the orthodontically-driven eruption of the multiple tooth impactions was presented and the reasons for directly relating its timing to the stage of development of the different groups of teeth (incisors, canines, premolars and molars) was explained. In that essay, there was a description and illustrated details of the Jerusalem method of achieving the assisted eruption and alignment of the incisors in both jaws.

Given ideal timing of this first eruption stage, it is to be expected that our hypothetical CCD patient should reach the completion of that stage at about the chronologic age of 12 years. At that point, the patient’s erupted dentition should include all four permanent molars and the central and lateral incisors of each side. It should also include incisor alignment, with the teeth proclined to normal labio-lingual angulations which occurs concomitantly with the increase in space in the canine/premolar areas. All of this will have been achieved with the use of coil springs on the long buccal arms of the 2-by-4 appliances used in the first eruption stage.

It was pointed out in both parts 1 and 2 that the dental development of the teeth in CCD affected patients is retarded by approximately 3 years, which means that our 12 year old patient’s dental age will be about 9 years, with the incisor root apices barely closed. At this age, the canine and premolar teeth are typically too immature to permit the commencement of the next stage since they exhibit less than half the expected final root length and wide open apices. A further 1-3 years will need to elapse before the requisite ½ to 2/3 root development is present and treatment should, therefore, be terminated.

In the patient illustrated in last month’s bulletin, treatment of the 1st eruption stage began late, at age 13 and, by the time it was completed, the unerupted premolars and canines had reached the state of development that was expected of an erupting tooth and, therefore, initiation of the second stage of treatment was possible immediately.

The question arises that perhaps we should start all treatment of CCD at age 13, in order to make a single phase of treatment. The answer to this encompasses two principal aspects, each important in itself. In the first place, social and psychological problems occur when a child reaches 8 or 9 years of age and still has no permanent anterior teeth. Most often, the deciduous teeth in CCD affected patients are completely invisible due to relative vertical undergrowth of the bony alveolus and there is a reduced height of the lower third of the face, giving him/her an edentulous appearance. Making that child wait till 12 years of age or later before teeth become visible is grossly unfair to the child. Delaying active eruption of these teeth may also reduce the tissue response to the extrusive forces applied, because the development of their roots will have been completed and any erstwhile intrinsic eruption potential may have been reduced to zero. Secondly, vertical growth of the alveolar bone is a function of the eruption of teeth and, it seems, the earlier this is done the greater is the potential for improving the balance of the face by increasing the height of the lower third. Results from patients treated in their later teens show considerably lesser degrees of growth in the vertical plane.

Setting up the patient for the second eruption stage

T_Fig.1

Fig. 1. August 2009, immediately prior to the second stage surgery. The first eruptive stage of treatment began at age 13 years – 3 years later than the optimum and eruption of the canines was included in that stage. At that time, brackets had been placed on the anterior 6 teeth in both jaws and the mandibular deciduous first molars, for additional archwire support. Alignment of each dental arch is good, although there is a distinct class III skeletal relationship. There are lingual arches soldered to the molar bands.

As we have noted above, treatment results from the first stage will typically feature a dentition with all four permanent molars and the central and lateral incisors of each side, together with the deciduous molars and canines in each quadrant. Incisor alignment and angulation will be normal and there will be adequate space in the buccal areas to accommodate the unerupted premolars and permanent canines (Fig. 1).

In many of these cases, we do not remove the initial appliances in the interim between the first and second stages. The factors that influence this decision are a high level of compliance with oral hygiene and if there is only a relatively short inter-stage time lapse, as seen in the patient illustrated in the October bulletin, who will also be presented here.

Thus, the appliances will consist of molar bands linked by soldered lingual arches and the practitioner’s usual orthodontic brackets on the incisors. The presence of single soldered round buccal tubes of 0.036” gauge on the first molars will later need to be substituted by rectangular tubes for the final alignment of the teeth, but the presence of the rigid lingual arches is very important to prevent buccal “rolling” of the molars secondary to the vertical eruption of the premolars and canines. Prior to the surgery now needed in the posterior areas, the labial archwire should be fairly heavy. Continuing the use of a Johnson arch, consisting of long round buccal tubes or 0.020” gauge and which slide easily in the round molar tubes has the advantage of rigidity in the posterior region while permitting a lighter anterior section of 0.018” or 0.020” in the incisor brackets. Alternatively, the use of a continuous 0.020” wire has the advantage of some flexibility in the long unsupported span between lateral incisors and molars, relying on the lingual arch to hold the molars from tipping mesially. Superelastic NiTi wires are unsuitable, since their vertical deflection cannot provide enough extrusive force to encourage eruption of 3 teeth together.

The orthodontist will also need to prepare a number of eyelet attachments threaded with soft ligature wire of 0.012” or 0.014” gauge ahead of time and these will take their place on the sterile tray that will be taken into the operating theatre, together with bonding materials and orthodontic instruments to be used in the placement and ligation of the eyelets to the traction mechanism. The soldered lingual archwire is not usually an impediment for the surgeon, although the labial archwire should be removed by the orthodontist on the day of surgery, either in or just before the patient enters the theatre.

Second stage surgery

The aims of surgery at this stage are to extract the deciduous canines and molars and any remaining supernumerary teeth. New radiographs at this point will confirm the further development of supernumerary teeth that had been diagnosed on the initial radiographs, but signs of development of additional extra teeth may sometimes be seen. Whether or not to perform a CBCT is very much a decision that must be taken by the orthodontist and surgeon involved, but they should both be cognizant of the number, frequency and dosage of past and future exposure to ionizing radiation to which these patients have been or will be subject in the future – and not just from the present episode of treatment.

We have performed second stage surgery under local anesthesia on conscious patients, but this approach must be carefully weighed in light of experience with the specific patient thus far and in consultation between orthodontist, oral and maxillofacial surgeon and patient. While there are advantages working on a cooperative conscious patient, this may involve more than one surgical session because 4 quadrants of the mouth are implicated and the patient’s own tolerance for these long sessions may be overtaxed. For the most part, general anesthesia is indicated.

The deciduous teeth should be extracted and a buccal flap elevated. The permanent premolars and canines of the normal series and the supernumerary teeth are recognized and the latter carefully removed. In the event that there are lingually located supernumerary teeth, the molar bands and soldered archwire will need to be removed and re-cemented later, following completion of the surgery for that jaw.

The orthodontist has a crucial role in the operating theatre and needs to be present to answer the surgeon’s questions regarding the aspect of each tooth to be exposed and the degree of exposed tooth surface needed for bonding. Bonding of the attachment to this site is best performed by the orthodontist who must dictate the location and direction that the pigtail ligature needs to exit the re-sutured flap at the end. The orthodontist’s strategy is not always understood by the surgeon and, if any of these tasks is left totally to the surgeon to decide and to perform, there will be occasions when a pigtail ligature will need to be subsequently re-directed, through a more suitable alternative exit through the ridge mucosa in order for forces to be applied to it in the appropriate direction. This would require further, albeit minor, surgical correction.

T_Fig.2 T_Fig.2cT_Fig.2d

Fig. 2. a. The maxillary left side after extraction of the deciduous teeth, a supernumerary tooth and exposure of the premolars.

b. eyelet attachments have been bonded to the two teeth. Note the extreme displacement of the second premolar whose apex is also displaced palatally and distally.

c. The maxillary right side after exposure and eyelet bonding and following extraction of a supernumerary tooth and the deciduous predecessors. The second premolar is grossly displaced palatally and mesially as on the left side.

d. Eyelet bonding completed on each side of the lower jaw.

The individual permanent canine and premolar teeth are minimally exposed on their buccal surfaces, as with the incisors in the first stage (Fig. 2a-d). Bone is not removed superiorly or mesiodistally, even if these teeth are deeply embedded in the basal bone. The surgeon isolates the teeth using retractors and sterile swabs, together with a fine suction tip. The area is rinsed with sterile saline and dried using suction rather than compressed air. The individual enamel surfaces of the teeth are etched using gel etchant to avoid spillage, rinsed off and the area dried again with the suction tip and, using light-cure bonding material, an eyelet oriented in line with the long axis of the tooth is attached.

T_Fig.3T_Fig._4

Fig. 3. The maxillary and mandibular right sides showing full closure of the surgical flaps over the teeth. In the mandibular arch, the soldered lingual arch was accidentally detached from the band on the left side and had to be removed, with the right molar band. This was reinstated a month later in the orthodontic office. In the mandible, the twisted stainless steel pigtail ligatures have been shortened and turned into closed loops close to the tissues. In the maxilla, they were turned into open hooks and used to ensnare the main arch in an active extrusionary mode.

Fig. 4. A panoramic view of the immediate post-surgery situation. Unfortunately, a supernumerary tooth escaped detection as the result of the superimposition of several teeth on the mandibular right side and remains in place. It was assessed that it would not prevent eruption of the premolars and was left in place.

It is important that both sides of the same jaw should be completed before proceeding to the second jaw. Once eyelets are bonded to the two sides of the same jaw, the archwire is re-inserted and re-ligated to the incisor brackets. Several options of applying forces to the impacted teeth are available and, whichever is chosen, they should ideally be completed before the surgical flaps are re-sutured to their former places to close off the surgical area as completely as the tissue will allow, leaving only the twisted soft steel ligature wire vertically exiting the sutured edges of the flaps (Fig. 3, 4).

Manipulation of the pigtail ligatures and application of extrusive forces are functions that may often transfer considerable force to the newly bonded eyelets and one or more may fail under the conditions prevailing in the theatre. With the excellent cooperation that we have developed with our collaborating surgeons, this is a rare occurrence. Nevertheless, it is preferable to apply the extrusive forces before suturing is done. Always remember: in the event of eyelet detachment, sutured flaps will need to be re-opened before bonding may be repeated!

Once the four quadrants are completed, archwires are slotted into the molar tubes and re-ligated in the anterior brackets. The application of extrusive forces to the premolars and canines should all be completed before the patient is wheeled out of the operating theater.

As noted in relation to the immediate post-surgery period following the exposure of the incisors, activation of the extrusive mechanism at the time of surgery permits the patient a month or so of healing to occur and for pain and discomfort to disperse before a new activation is needed. In some cases this single activation alone will bring a more superficial tooth to the surface.

The eruption mechanism

In the premolar area, the scope for designing an extrusion mechanism is very limited. Essentially there are just 2 principal possibilities.

1. The twisted steel pigtail ligatures exiting through the sutured edges of the replaced flap are turned over into small loops, as close as possible to the tissues. Elastic thread can be tied between the rigid side tubes of the 2-by-4 labial arch and these small loops, to provide an extrusion force of small range and of limited control in terms of the force applied, depending on the distance between the two.

2. If the archwire used is a stainless steel round wire of 0.020”, this offers a moderate degree of flexibility in the long span between lateral incisor bracket and molar tube. The twisted steel pigtail ligature is left fairly long and is used directly to entrap that section of archwire which has been pressed under finger pressure towards the replaced flap. The pigtail is turned over the archwire in the form of a hook, to hold it in its now activated mode. This has the advantage of simplicity in not requiring an additional tie and of providing a wider range of action.

A basic principle is that traction should be applied by ligating a flexible mechanism, such as a spring auxiliary or elastic thread, to a rigid archwire or TAD. The alternative is to tie a non-flexible steel ligature to a flexible archwire. There is no sense in using elastic thread on a flexible archwire or steel ligature on a rigid archwire.

Progress will be measured by the degree with which the twisted steel ligature lengthens supragingivally at the next visit. At that visit, the loop used as the point of application of the elastic thread is rolled up on itself, with a spring-former plier, until it is once again in tight contact with the healing soft tissue flap. It is then re-ligated with elastic thread in the same manner as before. In the second method, the hooked pigtail is shortened and again turned over the depressed archwire to reactivate. In both cases, the presence of the soldered lingual arch helps to prevent any mesial tipping of the molars that would otherwise occur. It is emphasized, as with the first stage concerning incisor eruption, the use of vertical intermaxillary elastics is most beneficial in encouraging the eruption of the teeth, in generating greater vertical growth of the bony ridges and in enhancing the usually reduced lower third of the face.

Once the teeth have erupted sufficiently for the eyelets to become visible, the distance between the attachments and the archwire becomes markedly reduced and, with it, a loss in the extrusive potential of the system. At this juncture, elastic thread will no longer be useful and pigtail ligatures will no longer displace the archwire vertically. The existing archwires are therefore discarded and substituted by a round nickel-titanium archwire of 0.014” or 0.016” gauge which is threaded directly through the vertically-oriented eyelets on the canines and premolars. Within 3-4 weeks, the teeth will erupt those last couple of millimetres and most of the existing rotations will be corrected.

T_Fig._5

Fig. 5. As the teeth erupt, their eyelets are substituted with regular orthodontic brackets. Note the loss of antero-posterior control with incisor retroclination.

The eyelets must now be removed and replaced by regular orthodontic brackets of the type used by the orthodontist concerned in any of his/her regular orthodontic cases (Fig. 5). The molar bands with the round tubes and soldered lingual arches are also removed and replaced by bands with the tubes and attachments favored by the orthodontist. The patient has now entered the routine orthodontic “ball park” and essentially becomes a run-of-the-mill orthodontic patient, like any other. What remains is to level and align, rotate, upright and torque the teeth in the manner normally carried out for any other orthodontic patient.

In common with a good proportion of CCD patients, the period of adolescence is often accompanied by a relatively rapid differential growth of the mandible and a lessened growth potential in the maxilla. This was seen in the case illustrated here and the reader is encouraged to compare the present records with the pre-treatment facial and intra-oral photographs of the patient displayed in last month’s bulletin (bulletin #26 October 2013) on this website.

Extreme tooth movement

In the illustrated case, the maxillary second premolars were severely ectopic. The crowns of these teeth were palatally displaced to a considerable degree, between 12 and 15mm from the labial archwire. Their roots were even more displaced towards the palatal midline, thus placing their apices about 20mm palatal from the line of the arch – their intended final resting place. How is it possible to move impacted teeth to that degree?

T_Fig._6

Fig. 6. The second premolars have been drawn from the palatal side and have been erupted buccally (arrows), across the line of the arch. They are rotated, their roots are markedly palatally displaced and buccal root torque is required.

With that degree of displacement, the angulation of the tooth in the maxilla was perhaps 45 degrees to the horizontal. By drawing the tooth towards the labial archwire, it was being drawn in the line of its own long axis. Thus, as the crown of the tooth came closer to the archwire, the apex was also drawn buccally, in a manner suggestive of being dragged along behind! The angulation of the tooth did not change. The crowns of these two premolars were drawn out buccally beyond their normal bucco-lingual positions, highish in the buccal sulcus, to erupt through the attached gingiva above the archwire (Fig. 6). The eyelets were then replaced by orthodontic brackets and the teeth torqued so that their crowns tipped inferiorly and their roots buccally and superiorly, causing them to upright into the alveolar bone.

Ortho-surgical jaw correction

T_Fig._7a T_Fig.7b_1

Fig. 7a, b. The achieved quality of alignment in light of the initial degree of ectopy of many of the teeth and the excellent state of health of the gingivae at the end of the second stage of treatment are difficult to see. This is because lip retraction in CCD patients is poor due to the typically reduced alveolar height and shallow sulci. Closed surgical exposure of the teeth, good directional traction and the use of small eyelets were largely responsible for the quality of the result.

Once all the permanent teeth have been mechanically erupted and aligned (Fig. 7), an evaluation must be made regarding the skeletal relationship between the two jaws. Does the skeletal relationship permit the orthodontist to think in terms of a purely dental correction? Perhaps a mild skeletal class III relation will justify aiming for a dental compensation. In the case illustrated here, the relationship is strongly class III and no amount of dental compensation can suffice to produce an acceptable result. For this to be corrected, surgical modification of the sizes and relative locations of both jaws vis-a-vis each other, the base of the skull and the facial profile, will be undertaken.