Short Notes in Plastic Surgery

January 11, 2016

56. Orthodontics for Children with Clefts

Filed under: Chapter 56 — ravinthatte @ 8:57 am

56. Orthodontics for Children with Clefts

This chapter is a product of an interaction between the compiler of these short notes and Drs. Chintamani and Rupali Kale who reserve two days in a week for treatment of children with clefts. Chintamani is an orthodontist and Rupali, a pediatric dentist. This chapter also has valuable inputs from Heemanshu Dave, orthodontist to the Smile Train project at the Godrej Hospital in Mumbai, India. All three practice in Mumbai.

  1. While general orthodontics, particularly its aesthetic branch can be both rewarding and remunerative, its poor cousin orthodontics for patients with clefts languishes a bit because the burden of care is huge for the parents, many of whom barely rise above the poverty line in India. The following paragraphs give a general outline of the role of orthodontia in children with clefts for the benefit of plastic surgeons who in a sizeable majority are at sea about that science.
  2. The middle-third of the face which includes the maxilla as well as the zygoma and the vertical ramus of the mandible constitute a much smaller part of the head at birth than that of adults.
  3. As the child grows these bones grow rapidly, both by absolute addition as well as sutural deposition and remodeling. The older idea that the growth of the mandible occurs mainly from a growth plate over its condylar head is not considered the whole truth anymore. The attachment of muscles, masseter and the medial pterygoid near the angle of the mandible, the lateral pterygoid on the condyle and the temporalis on the coronoid process exert a strong influence on osteogenesis in the growth of the mandible. The maxilla, though bereft of any strong muscular attachments usually grows by deposition of bone within itself and around the zygomatico-maxillary suture (see pictures below).

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  1. The plastic surgeon needs to be familiar with some basic facts regarding the jaws and the teeth. The primary dentition consists of twenty teeth which appear and fall between the ages of 6 months and twelve years, also called deciduous teeth. When permanent teeth start appearing during this period the phase of mixed dentition is reached. When all the teeth from the period of primary dentition fall away the stage of permanent dentition begins which ends when the jaws become edentulous. Even here the last third permanent molar may never erupt. Teeth in the mandible almost always appear earlier than the corresponding teeth in the maxilla.
  2. The dental development in children with clefts is subject to a variety of abnormalities and this to an extent applies to clefts of the lip as well even with minimal alveolar involvement. In complete clefts the tooth most commonly affected is the lateral incisor. The abnormality is less common during primary dentition because tooth buds are already in place prior to the development of the cleft. Even then the lateral incisor may be missing in about ten percent of cases during primary dentition as compared to almost 50 percent during secondary dentition according to some reports. When present the lateral incisor might be smaller and may erupt on either side of the cleft. Occasionally a supernumerary incisor is present and then the pair erupts on either side of the cleft. The central incisor on the non-cleft side is often narrower and this applies to both primary and secondary dentition. When the incisor tooth bud occupies the area of the cleft it may also get fragmented and fall off in pieces and therefore not erupt. The canine is rarely affected by the formation of the cleft. It is frequently impacted for lack of bone through which it cannot erupt and therefore is abnormally positioned.
  3. Also in patients with clefts, some other unrelated teeth might be missing. They might be smaller or erupt ectopically even through the suture line of a repaired cleft. During primary dentition the teeth may also show considerable delay in eruption in children with clefts.
  4. The development of the jaws depends on the presence of tooth buds or erupted teeth because they occupy space in the jaws around which bone is laid down. Temptation to remove teeth particularly adjacent to the cleft margins which have been affected due to poor oral hygiene and its effects must be avoided to preserve the height of the alveolar bone.
  5. Several reasons for poor oral hygiene in children with clefts are known. Anatomically due to the distortion of the arches because of the cleft, food residue tends to be left behind. Parents tend to indulge in children born with deformities and feed them with excess confectionary particularly chocolates. That is one culprit. Parents also tend to feed the children with pasty food for fear that they may not be able to eat and chew normal food and this food might be stuffed with excess sugar under the mistaken impression that free sugar is health giving. The cleft child is also given several syrupy medications. All this is reflected in a higher incidence of caries and decay in children with clefts due to a cario-genic environment. Also in the post-surgical period meticulous oral hygiene is difficult to maintain because of the wound and the pain that might be present and the fear that the repair might be damaged (please see pictures below).

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  1. Counseling therefore needs to begin very early. As it is, the first three or four months after the birth of the child with a cleft appear to be filled with a vacuum for the parents, the surgeon having pronounced that surgery can be undertaken at the end of that period. In an ideal clinic this time is used for counseling (as early as possible) and if this clinic is attended by several children with clefts at various ages together with their parents, a healthy interaction takes place in the waiting room and as a consequence they can reassure each other. The time is also used to fabricate a feeding plate which then can be fitted with nasal prongs and strapping of the lips can begin if possible (please see section on naso-alveolar moulding in chapter 53). The counseling about feeding is also undertaken during this period. Serial photographs as well as dental models of older patients can also be shown to the new arrivals. Such an ideal integrated clinic should be filled with pictorials and an alphabetical chart as well as books. This goes a long way in creating a spontaneous camaraderie amongst the parents of these children (see pcitures below).

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Photographs courtesy Chintamani and Rupali Kale, Mumbai

  1. The nature of deposition of bone has already been briefly mentioned in paragraph 3. Soon after birth the maxilla as well as the vertical ramus of the mandible grow forwards and downwards giving the face its convex appearance as well as height to the middle third of the face. The alveolar arches also expand centrifugally. And the opposition of the mandible to the corresponding part of the maxilla by way of the milk teeth produce a buttressing effect on each other leading to development of the alveolar ridges leading to normal occlusion (see picture below).

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  1. In children with maxillary clefts, growth may be affected partly because of the inherent mesenchymal deficiency which originally led to the cleft. What is more there is an assault of sorts (albeit well meaning) on the bone as the surgeon closes the cleft which may require some stripping of the oral and nasal periosteum over and under the palatine process of the maxilla as well as the palatine bone. Some dissection might also be needed around the maxillary tuberosity, the tuberosity being generally accepted as a growth centre. This leads to scarring. A congenitally crippled maxilla is therefore now strapped down by a scar (see following illustration).

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  1. The recent popularity of the one layer closure of the maxillary cleft with the vomerine flap has undoubtedly reduced raw areas as well as scarring (please see chapter 53 for technique of Vomer flap) but the jury is still out as to whether the procedure will reduce the vertical height of the middle third of the face over a period of time. As the face develops following surgery which nowadays is performed before the age of one year to allow development of good speech, the orthodontist is literally left holding the baby, the surgeon having removed his gloves and washed his hands off the case. The following paragraphs are about what happens in children with clefts after surgery. The paragraph immediately below also includes several technical terms which a plastic surgeon must be familiar with.
  2. Nisheet Agni, a maxillofacial surgeon attached to the Smile Train project at Godrej Hospital, Mumbai has provided the following figures.

Normal Occlusion:

Angle’s classification system is a method commonly used to classify various occlusal relationships.   This system is based upon the relationship between the permanent maxillary and mandibular first molars.

Class I (neutrocclusion) : In this normal relationship, the maxillary first molar is slightly posterior to the mandibular first molar:  the mesiobuccal cusp of the maxillary first molar is directly in line with the buccal groove of the permanent mandibular first molar.  The facial profile is termed mesognathic (please see illustration below).

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Class II (distocclusion): The maxillary first molar is either even or anterior to the mandibular first molar:  the buccal groove of the mandibular first molar is distal to the mesiobuccal cusp of the maxillary first molar.  The facial profile is termed retrognathic (please see illustration below).

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Class III (mesiocclusion): The maxillary first molar is more posterior to the mandibular first molar than normal:  the buccal groove of the mandibular first molar is mesial to the mesiobuccal cusp of the maxillary first molar.  The facial profile is termed prognathic (please see illustration below).

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A cross-bite defines a mode of occlusion where the maxillary molar is displaced medially or laterally to its corresponding molar in the mandible. This can either occur in the posterior or the anterior part of the arch. When the whole of the maxillary arch is accommodated within the mandibular arch then the bite is called a ‘scissor bite’. Please see illustrations below:

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  1. In children with clefts,

a.  The lesser segment or the part of the palatine process of the maxilla on the cleft side bears the brunt of the abnormality that is going to develop as the child grows.

b.  The normal horse-shoe shaped teeth bearing maxilla loses that shape mainly on the cleft side and tends to assume the shape of a triangle due to a collapse of the cleft segment because it is not joined to the opposite side (floats freely) or because of scarring.

c.  The normal side is usually less affected by the closure of the cleft and its growth as compared to the cleft side may mean that the incisors on that side cross the midline.

d.  The teeth particularly on the cleft side usually have a palatal inclination due to scarring produced by palatal surgery. The scarring can also lead to rotational deformities of the teeth.

e.  The cleft alveolar segment is smaller, may fail to grow adequately leading to crowding of teeth and impaction.

f.  The palatine inclination of the incisors as well as the poor alignment of the lesser alveolar segment with the pre-maxilla can lead to anterior cross bites.

g.  Both the downward and forward descent of the maxilla might be affected more so in its anterior half allowing adequate molar occlusion but an anterior open bite.

h.  And lastly maxillary abnormality and cross bites may affect the mandibular development as well because in the normal course the opposition of teeth of the two bones leads to a mutually coordinated development (please see pictures below).

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i.  The deformity of the cleft often superimposes upon the genetically ordained occlusal appearance.

15. Active orthodontic treatment can usually begin at around 8 years of age when the first permanent molar erupts and is mainly undertaken to either prevent a future collapse and more frequently for correction of deformation that has already occurred. The most popular appliance used for this purpose is called a quad-helix which is glued to the teeth. This has an inherent spring in it which expands the shape of the jaw slowly in the transverse direction. It is easy to maintain, not expensive and after some expansion occurs, when it becomes loose it can be changed or charged for further expansion. In case the expansion is adequate, it is retained to avoid future collapse till alveolar bone grafting is done (please see para 19). However when individual teeth or smaller segments need treatment, for e.g. to derotate them, brackets are put on the teeth and a wire is passed through the bracket, both on the larger and the smaller segment. The brackets can also accept elastic bands. This way the lesser arch as well as individual teeth can be pulled in specific directions in order to get them into good alignment. Occasionally these brackets will also help pull the teeth down to improve occlusion (see sequential photographs of a case).

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Some other examples of orthodontic correction of deformities in patients with clefts are presented below.

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All photographs courtesy Chintamani Kale, Mumbai

  1. Another method to expand the arch involves a transverse bar mounted on or glued to the molars on either side of the cleft and fashion a screw in the centre of the bar which can be turned to slowly increase the inter-molar distance. This method is less popular because it might cause some pain and turning the screw is not always easy for the parents. Should the screw get impacted or its holes are not properly seen, a visit to the orthodontist becomes essential. In severely deformed arches a quad-helix may need to be substituted with a tri-helix (see examples below).

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  1. A recent advance is the introduction of a nickel-titanium expander. The expander of the required dimension is first chosen, is compressed by hand and is fitted on the molars. Over a period of time the natural memory of the nickel-titanium expander causes the required movement of the segments. As compared to the stainless steel expander (quad-helix) this requires fewer adjustments and therefore fewer visits to the clinic. The appliance is however quite expensive.
  2. As normalcy is restored what in fact happens is the recreation of the original bony defect in the alveolar area. The stage is now set between the ages of 10 and 16 to find out which of the permanent teeth are missing and which are impacted and cannot erupt because of lack of bony support. In the past the recreated gap was ultimately bridged with a bridge (or a denture) sometimes extracting the uninterrupted canine or an abnormal lateral incisors to create conditions to mount the denture. The major change in the last quarter century has been to fill the recreated bony defect with cancellous bone grafts to allow consolidation and ideally to create a bony bridge between the opposing maxillary segments. This helps impacted teeth (particularly the canine) to erupt which can then be manipulated to get into its proper position. The unified consolidated maxillary segments can also be pulled forward to improve occlusion to as near to the class one position as possible. If the lateral incisor is missing, it is easier to move the canine in its place when maxillary consolidation or ossification is complete. This gives a normal appearance to the upper jaw.
  3. The decision as to when to perform bone grafting in the bony cleft with teeth on either side of the segment is decided by the orthodontist usually around ten years of age. In very narrow clefts or in clefts where some bony unison has occurred naturally through abutment, a bone graft may not be necessary. But when the bony defect has been fully recreated by the orthodontic work and a bone graft is advised the surgeon must keep the following in mind:

a.  The alveolar space where the bone graft is to be placed must be surrounded by healthy tissue. At the end of surgery this tissue should have been closed in a water tight manner.

b.  Towards that end oro-nasal fistulae must be closed in advance or should be securely closable at the time of bone grafting.

c.  Anteriorly flaps must be raised beginning with the gingiva going up to the sulcus and then incorporating the labial mucosa on either side of the cleft. These flaps should either close easily or if required, they should receive back cuts to convert them into advancement flaps. This is easier on the lateral side than the medial side.

d.  After the flaps are raised the periosteum of the opposing bony surfaces of the clefts must be raised by sharp dissection to expose the maxillary bone up to the apex of the defect.

e.  If this step inadvertently opens in to the nasal cavity, that hole must be securely closed by mobilizing local tissue.

f.  The bone grafts usually acquired from the iliac crest should be allowed to remain in their natural state even with some blood on them and are preferably not washed in saline. Pieces measuring 2-5 mm are cut preserving the cancellous part and removing as much of the cortical part as possible

g.  The pieces of the bone grafts are then picked individually with a plain forceps and placed in the alveolar gap. After the gap is filled some of these pieces will overlie the bare bone. They should be packed as closely as possible and hemostasis is checked again so that a haematoma does not form post-operatively.

h.  The flaps are then closed with some form of unabsorbable or long-duration sutures (please see below a photoshopped image followed by a clinical case).

i.  Post-operatively the patient is given to some form of liquid diet for 3-4 days semi-solid and normal diet can be started in stages.

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  1. While the concept of alveolar bone grafting is rational and scientific and aims to unite the maxillary bone across alveolar clefts, there are very few actual documented radiological photographs in the literature showing bony union. The failure of the first bone grafting procedure to create such a union has meant that a second bone grafting might need to be done within a year or two as shown in another case below. The severity of the maxillary retrusion in this case meant that a repeat bone grafting was essential to bridge the alveolar gap so that the maxilla could be pulled as a single unit (please see photographs below).

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Photographs courtesy Bharati Khandekar and Nisheet Agni, Mumbai

  1. What probably happens in many cases is there comes about some form of non-osseous fibrous union which holds the segments together enough for manipulating the maxilla to bring it forwards in the pubertal years. Even at this stage and later what is known as secondary bone grafting may be needed but these are known to fare even worse than the primary bone grafting. These procedures probably need more validation from the practitioners of this art with more convincing photographs of a bony union. It should be noted here that historically bone grafting in infancy as well as the technique of periosteoplasty (boneless bone grafting) have not succeeded and in fact led to deformities.
  2. What orthodontics cannot do has then to be corrected surgically. This branch of surgery is called Orthognathic surgery which will be covered in the next chapter and will be specifically about deformities in clefts.

Acknowledgments:

The illustrations in this chapter are photoshopped with the use of colour from Management of Cleft Lip and Palate, ed. by Watson, Sell and Grunwell, Whurr Publishers, 2001. The same book has been a source for some information contained in this chapter.

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