Cheilo Gnato Palatoschisis

CHEILO – GNATO - PALATOSCHISIS

Clefts are the congenital defects that may cause severe functional and aesthetic problems. The prevalence of the clefts has increasing tendecy. While at the beginning of this century it was about 1 in 1600, in 1940 it was 1:770 and in 1990 1: 500. The prevalence varies between racial groups. The clefts are very rare among the Negroes and the most frequent are in chinese, japanese and american indian population. There is often a history of clefts within a family but the mode of inheritance is not simple. Many enviromental insults to the embryo ( like an infectious diseases, corticosteroids, mechanical and chemical insults, alkohol, drugs, X-rays ) can produce clefts in animals but whether these are of any significance in human population is uncertain. Many classifications of clefts have been proposed but none is entirely satisfactory. Nowadays the classification based on embryological principles is used. So as to understand the mechanisms of the clefts and the principles of classification more easily it would be helpful to remind you the embryological development of the face and particularly development of the palate.

DEVELOPMENT OF THE FACE : Development of the face starts from ventral part of the head process of an embryo and the first branchial arch. The face develops mainly between the 5th and 8th weeks. By the end of the embryonic period ( eight weeks ) the face has an unquestionably human appearance. The first branchial arch develops two elevations called the “ maxillary prominence” and “mandibular prominence”. In the 4th week the five facial primordia are around the stomodeum ( primitive mouth ). The large “frontonasal prominence” constitutes the cranial boundary of the stomodeum. The paired “maxillary prominences” of the firsth branchial arch form the lateral boundaries and the paired “mandibular prominences” of the same arch constitute the caudal boundary of the stomodeum. Bilateral oval-shaped thickenings of the surface ectoderm, called “nasal placodes”, develop on each side of the caudal part of frontonasal elevation. 2/63 In this slide we could see the state at the beginning of the 4th week. This is the frontonasal prominence, the first branchial arch and the nasal placodes.

2/64 At the end of 4th week the stomodeum is surrounded by: frontonasal prominence the paired maxillary prominences the paired mandibular prominences and these are the nasal placodes

Horseshoe-shaped “medial and lateral prominences” develop at the margins of the nasal placodes. As a result, the nasal placodes lie in depressions called “nasal pits”.

2/65 these are the medial prominences, lateral prominences and nasal pits.

The maxillary prominences grow rapidly and soon approach each other and the medial nasal prominences. During the 6th and 7th weeks the medial nasal prominences merge with each other and the maxillary prominences. As the medial nasal prominences merge with each other, they form an “intermaxillary segment” of the maxilla. This segment give rise to: - the middle portion of the upper lip called the philtrum - the premaxillary part of the maxilla and its associated gingiva - the primary palate The lateral parts of the upper lip, most of the maxilla and the secondary palate form from the maxillary prominences. These prominences merge laterally with the mandibular prominences. The mandibular prominences merge with each other in the fourth week and the groove between them diappears before the end of the fifth week. The mandibular prominences give rise to the mandible, lower lip and the inferior part of the face. The frontonasal prominence forms the forehead and the dorsum and apex of the nose. The sides of the nose are derived from the lateral nasal prominences.

The palate develops from the primary palate and the secondary palate. The primary palate – or median palatine process, develops at the end of the fifth week from the innermost part of the intermaxillary segment of the maxilla. It forms a wedge-shaped mass of mesoderm between the maxillary prominences of the developing maxilla. The primary palate gives rise the part of hard palate anterior to the incisive foramen. The secondary palate – develops from two internal projections from the maxillary prominences, called the lateral palatine processes. These shelflike structures inicially project inferomedially on each side of the tongue. As the jaws develop, the tongue moves inferiorly and the lateral palatine processes gradually grow toward each other and fuse. They also fuse with the primary palate and nasal septum. The secondary palate gives rise the part of hard palate posterior to the incisive foramen and the soft palate. The fusion of the palatal processes begins anteriorly during the 9th week and ends posteriorly in the region of the uvula by the 12th week. The palatine raphe indicates the line of fusion of the lateral palatine processes. The posterior portion of the lateral palatine processes do not become ossified. They extend beyond the nasal septum and form the soft palate and uvula. So the classification that is used nowadays is based on these embryological principles.

CLASSIFICATION OF THE CLEFTS : The embryological classification divides clefts in four groups: 1. Clefts of the primary palate: may involve only the lip or the lip and alveolar process as far back as the incisive foramen. 2. Clefts involving both the primary and secondary palate. 3. Clefts of the secondary palate: may involve the soft palate only or the soft palate and hard palate as forwards as the incisive foramen. 4. Special clefts of the face: this group is not based on embryology but on the topography. It involve: medial cleft of the upper lip, medial cleft of the nose, aplasia of the ala nasi, unilateral or bilateral oblique cleft of the face, transverse cleft of the face, cleft of the lower lip, cleft of the mandible. These clefts are very rare.

MECHANISMS OF CLEFT FORMATION : A cleft is formed because the epitelium or the mesoderm failed to unite the various processes. A cleft also may be caused by inadequate mesoderm, or mesoderm that may have had insufficient migrating potential. It is thought that clefts of the primary palate result from failure of mesenchymal consolidation whereas clefts of the secondary palate may arise if the palatal processes fail to come into contact. MORPHOLOGY : Cleft of the primary palate : The deformity varies from notching of the lip to a complete lip cleft with alveolar involvement. It may be unilateral or bilateral. The most striking clinical feature of the unilateral cleft is the distortion that occurs due to the major segment of the alveolus moving away from the cleft side. Thus, the major segment is on the noncleft side, and the minor segment on the cleft side. The lip is distorted, and the nose is always flattened on the cleft side. The orthodontic and dental problems are local ones superimposed on the normal range of malocclusions. The alveolar cleft is in the lateral incisor area with the result that the anomalies of this tooth are often seen : it may be absent or poorly developed and/or malpositioned, or there may be dichotomy of the lateral incisor with one small peg-shaped tooth on either side of the cleft line. The central incisor on the side of the cleft is often rotated and hypoplastic. Normally the arch form is good. In the cases of bilateral cleft there is abnormal position of the primary palate, or premaxilla, which is rotated and everted out of the oral cavity. Thus the two major segments form the lateral aspect of the mouth, and the minor segment protrudes extraorally in the midline.

Clefts involving both the primary and secondary palates : These may be unilateral ( if primary palate involved on one side only) or bilateral ( if primary palate involved on both sides ). In cases of unilateral cleft there if a major segmet that consist of the lip, premaxilla, frontal and one lateral part of alveolar process, one half of the hard palate which is connected with womer and nasal septum. The minor segment comprise of the rest of lip, alveolar process and hard palate. There may be wide gap between the segments or they may collapse. In the cases of bilateral cleft the premaxilla with womer and nasal septum form an independent segment which protrudes extraorally in the midline or wedges inside the oral cavity. These cases present the greatest problems: surgical, dental, orthodontic and speech.

Clefts of the secondary palate : These vary from a submucous cleft of the soft palate to a complete cleft of the soft and hard palate as far forward as the incisive canal. The submucosus cleft means that there is diastasis of the soft palate muscles and space between them is filed by membrane. TREATMENT OF CLEFTS : In order to improve the function and appearance of the various parts of the face and oral cavity that are affected by cleft many different specialists have to work in close collaboration. A great deal of consideration must be given to the parents who may be under severe psychlogical stress and pressure from their family and friends. The mother in particular is often under considerable stress. Parents must be povided with adequate information about the future treatment and management of their child because almost all of them have the same concerns and questions. Before surgery it is helpful to warn parents about how the child will look immediately after surgery. They are then prepared to see the child with tubes and an intravenous drip in place. In addition it is helpful for the parents and the child to attend a clinic where there are other children with similar defects and problems. Couseling should be provided also for the child as he or she grows older.

Presurgical management of clefts : Although the tissue defects can be repaired and the functional problems can be minimized, careful management of the neonate is important for presurgical preparation. Because feeding is a major physical problem, it is essential to establish a satisfactory feeding technique as soon after birth as possible. It must be remembered that these babies take longer to feed than normal childs. The mother should be encouraged to breast feed the child whenever possible. However, sometimes the baby may not be able to generate adequate physiological reflexes to stimulate mother milk to flow. Bottle feeding may be difficult too because of inability to generate adequate suction. To overcome this problem, a long nipple or nipple with a flange is used. It has the effect of filling the cleft and directing the milk into the pharynx. If a large hole is made in the nipple, there will be a continuous flow of milk, which the child cannot control. A diagonal cross cut in the nipple prevents milk flowing unless the nipple is squeezed. Throughout bottle feeding the child should be in a semiupright position to prevent choking. Although spoon feeding is effective, it is very slow, which frustrates some babies and quickly tires others. Spoon feeding is espetialy useful immediately following repair of the lip, because it eliminates the change of damaging the lip. In order to cover the roof of the mouth and fill the space a feeding plate can be made. It fills the defect so that food and liquids do not enter the nasal cavity. At first an impression of the palate is taken using a specially constructed impression tray made from the cast of another baby with a similar type of defect and similar-sized mouth. After taking impression and making a study cast the area of the defect is filled and hard acrylic plate is fabricated on the model. The plate should de checked immediately after fitting and regurarly afterward at approximately 4-week intervals to see if major growth changes have occurred. If the jaws have grown we replace it. After any type of feeding, the mouth should be cleaned using sterile water and cotton-tipped applicators. In some cases a presurgical orthopaedic treatment is necessary to make surgery treatment easier. In the infant with a unilateral cleft of lip and palate the greater and lesser segments may be malrelated : they may be widely separated or over-lapping or somewhere in between. In bilateral cases the premaxilla is often far forwards of the lateral segments. Some surgeons consider that the surgical repair is easier to do if the segments are aligned before surgery. Presurgical orthopaedic treatment is performed by fitting either a hard or a soft acrylic plate. The hard plate is designed to mould the gum pads into right position and is usually supported by a headcap. In bilateral cases, the headcap may be used to apply distal traction to the protruding premaxilla. Soft acrylic plates are trimmed (eased) on the palatal surfaces to allow the segments to aline as growth takes place.

Surgical management of cleft lip and palate : Surgery usually begins at approximately 3 month of age and involves repair to the lip. The alveolar defects may also be repared at this time. Clefts of the hard and soft palate are usually repared at about 18 months of age. Surgical treatment is performed not only to improve appearance but also to facilitate eating and drinking without nasal spillage. Futhermore, surgery should reduce the likelihood of recurrent middle ear infections, which may lead to deafness and reduction in speech quality. Some surgeons prefer to operate at an earlier age (6-12 months) before the child develops adaptive speech habits. Others repair the soft palate at 18 months but delay the hard palate repair until further maxillary growth has taken place. The correction of the cleft defect is not simply. There is a total absence of tissue in the cleft region. Hence, any attempt to repair the defect by directly uniting the edges will cause distortion and a reduction in the overall size of the arch. Closure of the defect must be made on both the oral and nasal sides with the minimum of tension. Soft tissue flaps are raised and mobilized from the regions lateral or posterior to the cleft. The greater palatine vessels are the major source of blood to the palate, and they should not be damaged. The denuded areas of the palate are then left to epitelialize. When the tissue available on the palate is insufficient, an alternative source of tissue for the repair is the dorsum of the tongue. Even with the best surgical techniques available, the scar tissue that result from the repair may adversely affect the anteroposterior and transverse development of the palate and whole maxilla. Where the hard palate has been repaired, the upper arch is often narrow with the result that some crowding and a crossbite ( uni- or bilateral ) may be present. The anteroposterior deficiency of the maxilla gives rise to a Class III skeletal pattern and often to a Class III incisor relationship. The skeletal malrelationships become more severe as the child grows. For adolescents with severe discrepancies in jaw sizes in the anteroposterior plane, major facial surgery can significantly improve the aesthetics and function. This is a major decision and requires great care to assess for lack of anterior development of maxilla or mandibular prognathism. Surgery may take the form of maxillary advacement, mandibular osteotomy, or reduction of the chin. Such treatment is usually conducted after growth has finished and in conjuction with orthodontic therapy. Repairs of the lip and palate are the two major surgical procedures. However, as the child grows other problems must be solved. Often small or even large oronasal fistula develops. The nose is frequently distorted and needs surgical revision. Scar tissue in the lip gives it an uneven appearance. So the child often has to undergo secondary operations to the nose, lip or palate. This must be taken into account in planning the dental management.

Orthodontic treatment : The objectives of treatment are the same as those of surgery : that appearance, speech and function should be as good as the circumstances allow. No orthodontic treatment is advised until the permanent incisor erupt. The extent of a malocclusion is usually less apparent in the primary dentition and the level of cooperation that can be expected from child of this age is fairly limited. The child should be seen at regular intervals for routine dental checks and treatment. Discrepanties in arch alignment and relationships are beginning to worsen by the mixed dentition phase. Anterior teeth are frequently malformed, hypoplastic, erupt in ectopic positions or they may even be missing. It is difficult to be sure if these problems have been caused by the cleft defect only or also by the surgical repair. At this stage should be carried out : 1. Correction of lingually placed permanent incisors 2. Supernumerary or malposed teeth may have to be removed surgically. Lateral expansion of the narrow upper arch should not be undertaken at this stage as it will not be stable. At early permanent dentition stage a full diagnosis and treatment plan must be formulated. The chil´s general dental condition, cooperation, traveling difficulties, and the limits set by the skeletal pattern and soft tissues must be taken into consideration. Treatment varies according to the severity of the case. 1. Where there are reasonable arches with minimal anteroposterior and transversal discrepanties , orhtodontic treatment, ideally followed by bridgework to replace missing or malformed teeth, is indicated. 2. Where the discrepancy in arch relationship is moderate or the patient is not suitable for complex appliance treatment, it is often best to remove poorly formed and malpositioned teeth and to fit a metal denture to give a reasonable appearance without damaging the soft tissues. 3. In severe cases where orthodontic and prosthetic techniques alone will not give a satisfactory aesthetic result, surgery to improve the patient´s profile may be indicated. This will usually involve the maxilla and sometimes a combined maxillary/mandibular operation. Surgery may be preceded or followed by the orthodontic treatment and finaly restorative procedures. Rapid expansion of the upper arch is sometimes indicated in order to improve the arch form and buccal segment relationship with the lower teeth. It is undertaken using cast cap splints cemented to the teeth and a large screw activated two or three times each day. The expansion is rapid so that the maxillary segments, rather than the teeth, are moved. However, the expansion is rapidly achieved, it will not be stable unless it is permanently retained.

Restorative treatment : The long term restorative plan should be considered before orthodontic treatment is begun. It may be possible to simplify orthodontic treatment, if for example a rotated tooth is to be incorporated as an abutment in a bridge. In addition, in some cleft patient longterm permanent retention may required using a fixed retainer or a prosthesis. Any prosthesis must be designed carefully because it must not damage the abutment teeth, induce pathologic changes in oral mucosa or compromise the oral hygiene. Consequently, a prosthesis with a metal rather than acrylic base is more desirable to maintain a high level of oral hygiene. Speech therapy : Cleft palate patients have also speech problems, in part because the soft palate tends to be rather short and lacking in mobility, so that during the speech there is a nasal escape of air. Many also have hearing defects due to middle ear infections. Speech therapy is an important part of the total treatment. Despite their difficulties, a remarkably high proportion of these children have quite good speech.

Conclusion : The surgical, orhtodontic and speech problems of cleft palate children are treated by a team of specialists. The general dental practitioner should also be part of that team. He must concentrate on preventive dental measures and early treatment of carious lesions. Only if the child is dentally motivated and enjoys a high standard of dental care can the best be done for him by other members of the team.