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Orthodontic Management of Unilateral Cleft Lip and Palate KARIN

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Orthodontic Management of Unilateral Cleft Lip and Palate KARIN Orthodontic Management of Unilateral Cleft Lip and Palate KARIN VARGERVIK, D.D.S. San Francisco, California 94143 Experimental and clinical findings indicate that unfavorable adaptations of normal structures occur in children with clefts. It is postulated that these deviations from normal development are reversible and can be corrected or prevented by properly designed treatment. On this basis, five hypotheses were formulated and tested on the data from the subjects included in this study. The subjects consisted of 1) 16 children without clefts, 2) eight children who had complete unilateral clefts of the lip and palate but who had not received orthodontic treatment, and 3) 16 children who had complete unilateral clefts of the lip and palate and who had been treated by the described orthodontic procedures. The mean age for each group was 16 years. It was concluded that orthodontic treatment can be designed to: 1) counteract the forces which inhibit development of the maxillary alveolar process horizontally and vertically, 2) partially prevent the reduction in the forward growth of the maxilla, 3) provide adequate jaw and dental arch relationships, and 4) establish and maintain correct position of the maxillary segments. KEY WORDS: Cleft palate, cleft lip, orthodontics Introduction should be brought into positions that mini- mize the effect of their inadequacies. Craniofacial growth and development in A clear distinction between the primary individuals with clefts of the lip and palate and secondary effects of clefts on the facial are influenced by irregularities in embryonic skeleton and soft tissues cannot be made in development, which cause tissue deficiencies, children. An experimental model was, there- and by lip and palate surgery, which results fore, developed in our Center and has been in scar tissue and contractures. These influ- used in a series of experiments. A cleft condi- ences on growth may act directly on devel- tion was produced surgically in normal rhesus oping structures or may indirectly affect monkeys. A complete cleft of the bony palate growth patterns through deviant muscle ac- and alveolar process was made, and one cen- tivity. The commonly observed findings of tral and one lateral incisor were removed. The irregularities in the nose, palate, and pharynx maxillary segments were moved medially in may affect speech, mastication, respiration, order to collapse the maxilla and to prevent and the positioning and movements of the healing of the bony cleft. The effects of these tongue. changes on the adjacent structures were stud- Appropriate treatment planning requires ied. The findings showed that the structural that distinctions be made between embryonic deviations which developed were comparable defects and subsequent adaptations of normal to those that occur in children with unilateral structures to their altered environment. Ther- clefts (Chierici et al., 1973, a,b). This indicates apy should focus on providing conditions for that structures with normal growth potential optimum development of structures that have may develop abnormally in a cleft environ- normal potential for development. Those ment. structures which cannot develop sufficiently Background Staces or DEVELOPMENT IN UNILATERAL Dr. Vargervik is Associate Professor in Residence, CiiErts. Clinical studies have demonstrated Center for Craniofacial Anomalies, University of Califor- that the characteristic abnormalities vary nia, San Francisco, San Francisco, California. among individuals and change significantly Presented in part at the 36th Annual Meeting of The American Cleft Palate Association, San Diego, Califor- during growth. The following developmental nia, 1979. stages should be distinguished: 1) infancy, 256 Vargervik, ORTHODONTICS IN CLEFT PALATE 257 before surgical closure of the lip, 2) post-sur- further medial movement of the segments gical closure of the lip and palate until the unless teeth and subsequent bone in the cleft shedding of the primary deciduous incisors, 3) are lost. The degree of maxillary width reduc- early mixed dentition, and 4) adolescent tion is consequently closely related to the growth period. development of the alveolar processes; and this, in turn, is determined to a large extent Stage 1: Infancy, before surgical closure of by the number, position, size, and shape of the lip the teeth in that area (Harvold, 1954). Early The characteristic defects in the infant are removal of teeth in the cleft is, therefore, primarily localized in areas bordering the contraindicated. cleft. These include the nose, lip, hard and The deciduous dentition is usually com- soft palates, and alveolar processes adjacent plete. Supernumerary teeth in the cleft occur to the cleft. more frequently than congenital absence of The nasal septum, vomer, and alae are the teeth. The alveolar processes are generally severely distorted in unilateral clefts. The na- well developed and stable as long as the de- sal septum is usually curved over the cleft, ciduous dentition is intact. Crossbite of one or and the conchae on the side of the cleft are more teeth on the cleft side is the most usual smaller than on the noncleft side. deviation from normal dental arch form dur- The orbicularis oris musculature is inter- ing this stage. rupted, and muscle mass and fiber direction Stage 3: Early mixed dentition vary considerably (Fara, 1968). There is much individual variation in width and position of The transition from deciduous to mixed the shelves of the hard palate (Garber, 1949; dentition is characterized by an increase in Coupe and Subtelny, 1960). The soft palate discrepancy between maxillary and mandib- also demonstrates wide variation in the extent ular sizes and dental arches (Harvold, 1954; and direction of muscle fibers (Ruding, 1964; Ross, 1970; Bergland and Sidhu, 1974; Bis- Kriens, 1969; Latham et al., 1980). The an- hana et al., 1979). The permanent lateral terior part of the large maxillary segment is incisor on the side of the cleft is frequently usually protrusive and deflected to the non- missing, and there is a high incidence of con- cleft side (Harvold, 1954; Pruzansky, 1955). genital absence of bicuspids (Bohn, 1963). The alveolar processes in the cleft margins are The central incisor on the cleft side is on an usually somewhat deficient in vertical height. average 10% narrower than the other central incisor, and its shape is often abnormal (Har- Stage 2: Post-surgical closure of the lip and vold, 1947). The path of eruption of the cen- palate until the shedding of the deciduous tral incisors is lingual and toward the cleft, incisors _ and these teeth are usually severely rotated as The surgically closed lip and palate ap- well (Subtelny, 1966). Further medial dis- proximate normal lip and palate morphology. placement of the alveolar process on the cleft However, the repaired lip and palate will not side and an increased incidence of anterior necessarily continue to develop favorably in crossbite usually occur during this stage. either morphology or function because of neu- When the maxillary segments are displaced -romuscular abnormalities and scar tissue. The medially, the tongue cannot be accommo- molding effect of the surgically restored lip on dated in its normal position in the palate. The the protruding large maxillary segment has position that the tongue acquires becomes been well documented (Harvold, 1954; Pru- decisive for the pattern of further develop- zansky, 1955). ment of the maxilla as well as of the mandible. Medial movement of the lateral segments, If nasal respiration is adequate, the tongue particularly the lesser segment, subsequent to may be positioned below and in contact with lip and palate closure, is also a consistent the occlusal surfaces of the maxillary teeth finding. The maxillary segments usually con- during rest. When this occurs, alveolar height tact each other in the alveolar region by ages is inhibited even in the absence of restrictive four to five (Harvold, 1947; Pruzansky and scar tissue. If nasal respiration is impeded, the Aduss, 1964, 1967). This contact counteracts tongue may assume a low posture in order to 258 Cleft Palate Journal, October 1981, Vol. 18 No. 4 facilitate oral respiration. If the tongue in this movement of the cleft segment. The ala nasi low position does not rest under the occlusal move laterally and become flattened on the surfaces of the maxillary teeth, the alveolar cleft side. The ridge of the nose and the nasal height will increase and result in a progressive septum, which, at the onset of the experiment, lowering of the mandible, a more open gonial were straight, curve over the cleft, and the angle, and a more retruded position of the conchae on the side of the septum convexity chin (Harvold, 1954; Harvold et al., 1972). become smaller. The maxillary incisors tilt Studies on skeletal morphology and size in lingually and deviate toward the cleft, result- unilateral cleft lip and palate have shown few ing in an anterior crossbite (Chierici et al., differences from average values for normals in 1973a) (Figure 1). In the mandible, the inci- the late deciduous and early mixed dentition sors become more upright and have a tend- stages (Mazaheri et al., 1967; Aduss, 1971; ency to become crowded; the anterior alveolar Nakamura, 1972; Mapes et al., 1974; Krog- height increases, and the gonial angle is more man, 1975). However, at this age, retrusive- open (Chierici et al., 1973b). ness of the anterior part of the maxilla as well These findings led to the conclusion that as progressive retrusiveness occurring during the palatal tilting of the maxillary incisors later growth have been reported (Harvold, and the mandibular changes were adapta- 1954; Lande, 1970; Hayashi et al., 1976). tions to a lowered postural position of the mandible and tongue. This lowered position Stage 4: Adolescent growth period was necessitated by tongue displacement, In non-cleft children, the average yearly which was caused by the induced reduction increase in mandibular length from six to 16 of the palatal vault and arch width.
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