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The team approach to attachment bonding
ОглавлениеIt is appropriate to note that the development of the team approach to the bonding of an attachment was exemplified in the cooperation, expertise and forbearance of two (now retired) senior oral and maxillofacial surgeons in Jerusalem, Professors Arye Shteyer and Joshua Lustmann. The approach primarily represents an adjunctive surgical procedure, whose aim is to provide a small area of exposed enamel of the impacted tooth for the application of an orthodontic force‐delivery system. Accordingly, it should be carried out on the surgeon’s territory, rather than in the orthodontic clinic.
Before the surgical exposure is attempted, orthodontic treatment will have been initiated and, in most cases, will have reached the stage where levelling and alignment will have been prepared. More substantial steel archwires will have been used during space preparation and a heavier base arch will usually be in place to combine all the teeth into a composite anchor unit.
Those orthodontic procedures that remain to be carried out during the surgical episode are few and relatively simple and can all be performed in the oral surgeon’s operatory. If they are properly prepared in advance, these procedures will not be time‐consuming and will not disturb the surgeon’s patient flow. Practical experience will dictate that the orthodontist should prepare a small tray of instruments and materials that are not normally available in the operating room. In addition, the orthodontist will have prepared an auxiliary device, which will have been chosen or customized at a previous visit, for the purpose of applying a directional force to the impacted tooth. This may take the form of a prepared and individualized ballista spring, or a flexible palatal arch or an auxiliary labial arch (see Chapter 7). The instrument tray should contain the items listed in Table 5.2.
In the treatment of an impacted palatal canine or of almost any other impacted tooth and immediately prior to the surgical exposure, it has been the author’s practice to tie the labial auxiliary arch or other auxiliary into the orthodontic brackets. In its passive mode, the active loop will stand well away from the immediate surgical field and will not interfere with the work of the surgeon. As a poorer alternative, these auxiliaries may be placed on the instrument tray, in readiness for placement at the end of the surgical procedure.
Table 5.2 An instrument tray for a team approach.
Instruments |
---|
Fine wire bending plier (e.g. Begg plier) |
Fine wire cutter |
Reverse‐action bracket‐holding tweezers, which are closed when not held and release when handles lightly squeezed |
Ligature director |
Mosquito or Matthieu forceps |
Fine scaler |
Materials |
Etching gel |
Composite bonding material, preferably a light‐curing material |
Applicators (sponge buds, fine brushes, etc.) |
Attachments |
Eyelets welded to thin band material, backed with stainless steel mesh; these should be cut and trimmed into patches of various sizes, but no larger than the base of a small bracket |
Cut lengths of dead soft stainless steel ligature wire of gauge 0.012 in. or 0.014 in. |
Elastic thread and elastic chain |
In the first stage of the treatment, the surgeon reflects the palatal soft tissue flap over the impacted tooth and removes the intervening bone, which is usually very thin and easy to peel with a scalpel blade. If a supernumerary tooth or odontome is present, this will be removed first. The dental follicle is then cut open in the target area, immediately overlying the crown, and the resultant exposure is widened. The increase of the width of the exposure should not be more than is necessary to satisfy two basic requirements: (a) to provide enough enamel surface to accept a small attachment; and (b) to do so in an area wide enough for adequate haemostasis to enable the bonding procedure to take place, without fear of contamination.
The next stage requires the surgeon to move to the other side of the operating table in order to be positioned to concentrate on maintaining the enamel surface, free of blood and saliva, throughout the critical bonding phase. In this function, and under these conditions of exposed and oozing soft tissue and bone surfaces, the surgeon will generally need to use a regular suction tip and a second and very fine tip in the form of a canula no. 14 or 16, in order to maintain a blood‐free field of operation for the bonding procedure. Occasionally, the surgeon may be required to attend to a persistent bleeding point from the bone surface and may apply pressure from a blunt instrument or use bone wax to occlude the tiny vessel. In the case of soft tissue bleeding, electro‐cautery may be employed, or a hot burnisher or even ligation of the vessel. Bleeding does not occur in the follicular space, but seepage from adjacent areas may happen and is best arrested with the use of light pressure from a strip of gauze, which may be left in place until suturing is ready to begin – but it must not be forgotten! Then, holding a retractor in one hand and alternating the suction tips as necessary with the other, the surgeon will be able to maintain the access and haemostasis to the immediate area of the newly exposed and impacted tooth.
The orthodontist, who has been waiting patiently for the surgeon to achieve the required state, will now step in and proceed directly to rinse the tooth surface with atomized water spray. This will be done from a standard triple syringe (or, if preferred, with sterile saline from a large syringe) through a wide‐bore needle, in order to disperse any blood from the tooth surface. The saline is evacuated through the broad suction tip, operated by the surgeon. The fine suction tip then takes over and is made to hover over the entire exposed crown, close to the tooth surface, with the aim of achieving an air flow over the clean enamel. This produces and maintains effective drying, while the use of sterile saline as a rinsing agent does not appear to undermine the reliability of the bonded union.
Liquid etchants should not be used in the exposed surgical field [5, 25, 45], since it is difficult to limit their spillage and dispersal onto the exposed soft tissues and bone surfaces and, even more important, to prevent their spreading to the area of the CEJ, the PDL and cementum. There is mounting clinical evidence that excessive orthophosphoric acid etchant, which seeps onto the exposed root areas, will damage the cementum cover of the root. It may also enable the osteoclasts of the PDL to attack the naked dentinal root surface and thereby create a focus of invasive cervical root resorption. The etchant should be applied by the orthodontist in gel form on the end of a fine sponge bud or fine instrument. It should be left in place for 15 seconds and thereafter drawn off by the surgeon through the fine suction tip, before the surface is rinsed again with saline to remove the last traces of acid.
Continued use of the fine tip for a few more seconds will draw air over the surface of the crown of the tooth, until it is dry and the typical white matt appearance of the etched surface becomes apparent. The surface is now ready for bonding. Many practitioners may feel concern about the adequacy of the desiccation and may also prefer to be sure that no salt crystals remain from the dried saline. Experience shows that this concern is without foundation. Nevertheless, to allay these doubts, a final rinse with atomized water from the triple syringe may be carried out and followed by a fine compressed air stream, thereby doubly ensuring the appropriate degree of dryness of the enamel surface. Care must be taken that the compressed air stream be very gentle, in order to avoid splashing up blood from the surgical area, contaminating the enamel and causing bond failure. Oddly enough, the use of a suitably adapted electric hair dryer has the advantage of providing a gentle and waterless stream of warm air, which may be more effective in drying the etched enamel surface and is a method favoured by some clinicians.
The prepared eyelet attachment has a pliable base. An attachment of appropriate size should be selected and manually adapted by the orthodontist with pliers to conform to the target bonding site. A cut length of 0.012 in. (0.3 mm) or 0.014 in. (0.35 mm) soft stainless steel ligature wire is threaded through the eyelet and, with the use of mosquito or Matthieu forceps, is twisted into a medium‐tight and firm pigtail, which should swing freely in the eyelet. Although any type of bonding agent may be used, we have found that light‐activated systems are easier to handle in these circumstances than chemically activated systems.
The subject of attachments is discussed in more detail in Chapter 2. Nevertheless, one or two points are pertinent in the present context regarding bonding under conditions of surgical exposure.
The choice of the appropriate implement to be used, to carry the attachment to its place and to hold it there until setting has occurred, is also important. Many operators prefer to use mosquito or Matthieu forceps; however, freeing the instruments from the attachments is only possible to achieve by changing the hand grip and unlocking the ratchet that holds the beaks closed. These manoeuvres produce considerable jolting and jarring of the attachment and could cause loss of the delicate control needed for successful, accurate placement. Experience has shown that it is better to use reverse‐action bonding tweezers, which, once the attachment has been placed, may be much more gently disengaged, to be left unsupported during the curing process.
The viscosity of the bonding paste should be adequate to prevent any ‘floating’ movement. However, if continuous pressure is desired during the setting period, one may place a ligature director, with its notch engaged, astride the eyelet loop and under light pressure. The freeing of the ligature director, once setting is complete, is achieved simply by merely withdrawing the instrument in the direction of its long axis, without generating any undue lateral jarring. It is always advisable, before requesting the surgeon to re‐suture the flap, to test the strength of the newly bonded attachment by giving the pigtail ligature a firm tug.
As part of the original orthodontic treatment plan, an accurate radiographic assessment of the position of the impacted tooth will have been made and an approach to its orthodontic resolution formulated. With the impacted tooth in full view during the exposure procedure, the orthodontist must re‐evaluate the earlier assessment and confirm or revise the traction direction accordingly. If the traction is to be directed in line with the prepared place in the dental arch, then the pigtail ligature will be swivelled on the eyelet until it points in that direction. The surgeon will then suture the flap back over the wire, leaving its end freely protruding through the cut and sutured edges.
As will be discussed in Chapter 7 with regard to a palatally impacted maxillary canine, sometimes the direction of the traction cannot be pointed straight to the labial archwire, due to the proximity of the roots of adjacent teeth. In such a case, the wire may initially need to be drawn vertically downwards towards the tongue, or posteriorly towards the molars. To achieve this, the pigtail, which cannot be drawn through the sutured edges of the flap, will rather be taken through the middle of the palatal area. This means that the reflected flap will need to be divided into two, one on each side of the pigtail (Figure 5.6g). A better alternative, prior to the replacement and suturing of the flap, is to pass the pigtail through a small pierced pinhole in the palatal flap mucosa. When suturing is finished and the palatal area completely closed off, the orthodontist should shorten the pigtail and turn it up into a hook or a circle, to be attached to an active palatal arch, ballista, auxiliary archwire or elastomeric chain, according to preference and suitability.
The replacement of the flap will once again conceal the impacted tooth. However, before it is hidden by the closure, it is prudent to photograph the tooth and its attachment (Figure 5.6d, e). This will be appreciated at a later stage, when the patient returns for routine orthodontic adjustment and further activation of the traction mechanism. It will enable subsequent decisions related to the direction of orthodontic traction to be made with greater reliability.
Traction should be applied immediately after the closure has been achieved and regardless of which traction method is used. This will help to reduce later manipulation of the ligature pigtail, which is very helpful, particularly during the first couple of post‐surgical months. Such manipulation is unpleasant and even painful for the patient as the pigtail passes through the soft tissues.
There is much to be said for the first adjustment being fully exploited, with the application of appropriate traction while a local anaesthetic is still operational, i.e. at the time of surgical exposure. Subsequent manipulation may then only be necessary for two or three additional adjustment visits, before the tooth is erupted and before the pigtail becomes free from the soft tissue. If, prior to the surgery, an auxiliary labial archwire or a ‘ballista’ spring in its passive mode has been tied into the arch, as already recommended, then lightly pushing the loop from its vertical, inactive position towards the mid‐palate and turning the pigtail ligature around it will provide appropriate light and continuous extrusive force. This will be active over a wide range of movement and will remain active for many weeks. Similarly, an auxiliary palatal arch may be slotted into the palatal horizontal molar tubes then raised, to be held by the pigtail ligature. Whichever of these devices is used, this orthodontic manoeuvre should take no more than a minute or two and can be done while the surgical instruments are being cleared away.
With the procedure described, and attachment placement performed by the orthodontist and with moisture control under the care of the surgeon, the bonding has been shown to be very reliable [3]. However, this has not always been the prevailing opinion. In the past, bonding in the presence of an open and bleeding wound, involving both soft and hard tissues, was strenuously resisted, since it was thought to be inconsistent with the attainment of a dry and uncontaminated field. This mistaken opinion on the part of the orthodontist was probably born more out of a reluctance to be present at the surgical episode than out of any experience of a high incidence of failure in attachment bonding in these circumstances.
From the discussion here, it will be abundantly clear that the presence of the orthodontist at the surgical intervention has multiple positive aspects:
The orthodontist is able to see the exact position of the crown, the direction of the long axis and the deduced location of the root apex.
The height of the tooth and its relation to adjacent roots may be noted and the orthodontist will be able to confirm the strategic plan for its resolution by direct visualization.
The orthodontist will be in a position to decide, from the mechano‐therapeutic aspect, exactly where he or she would like to see the attachment placed and will bond it there.
The orthodontist is also the best person to fabricate, place and activate a suitable and efficient auxiliary to apply a directional force of optimal magnitude and range of movement and to do so at the time of actual surgery.
It is not fair to expect oral surgeons to be aware of how the different attachment locations may affect the orthodontic or periodontic prognosis; nor should they be expected to be sufficiently experienced with the bonding technique to do it themselves. Bonding is not a procedure that oral surgeons routinely carry out. The presence of the orthodontist allows for bonding to be performed efficiently, while the surgeon and the nursing attendant maintain haemostasis and the necessary dry field.
Some surgeons may take exception to the presence of the orthodontist at the exposure and may even use expressions like ‘even the lowliest oral surgeon can place a bracket’ or that it is ‘a waste of time’ [52]. It will then be quite apparent that the oral surgeon had sorely missed the point and had not understood the wider context of ensuring quality care and overall treatment success.
The ultimate responsibility for the success of the case rests firmly on the shoulders of the orthodontist, from the initiation of orthodontic treatment up to the point where the impacted tooth is brought into full alignment and, almost invariably, until the overall malocclusion is resolved. It would be irresponsible to abrogate the management of this crucial stage of the treatment to another party, when there is force to be applied to the newly exposed impacted tooth and where so much is at stake that will affect the future of the case. If, as has been advocated by many orthodontists and surgeons alike, orthodontists absent themselves and leave surgeons to make orthodontic decisions for which they are not equipped, they will be endangering the outcome and inviting legal proceedings, from which the orthodontist involved will not be immune.