Etiology. Contributions to the etiology of dento-maxillo-facial anomalies during the period under review can be discussed, from the standpoint of genetic, systemic, prenatal, postnatal environmental and local causes. Etiologic factors may express themselves indirectly through general constitutional changes or directly on the dento-maxillo-facial area. They may affect structure or its form and function. The anomalies may be symmetrical or asymmetrical and of different degrees of severity. Different etiologic factors may give rise to the same type or classification of malocclusion and, conversely, malocclusion of the same classification may be due in whole or in part to different, unrelated causes. Favorable genetic influences lead to normal growth and development. When they are unfavorable, they may lead to abnormalities of the dento-maxillo-facial area. Environment is frequently the deciding factor in the extent of the manifestation of abnormalities of genetic origin. Although the genetic growth pattern tends to manifest itself during growth and development, it can nevertheless be favorably modified by present orthodontic methods. Congenital abnormalities may or may not be of genetic origin. They may be due to abnormal state of the pregnant mother or to deficiencies in the fetus. Body build presents a new classification of importance to the orthodontist in establishing etiology and in treatment planning. Cephalometrics as a method of establishing the etiology of dento-maxillo-facial anomalies in individual cases cannot be used with a high degree of certainty until ‘base-lines’ are established for the respective mean measurements. Such base-lines must show unique association with specific types of dento-maxillo-facial anomalies, including malocclusion of the teeth. Variations in the morphology, number, time and order of eruption of the teeth are important etiologic factors in the establishment of malocclusion. Maxillary midline diastemas are as a rule normal developmental phenomena due to the pre-eruptive position of the incisors and canines; they may also be indicative of malocclusion. Muscle function, especially the size and function of the tongue, is an important etiologic factor in malocclusion. Muscle balance determines the ‘area of tolerance’ within which teeth will remain after orthodontic treatment. Disease and nutritional disturbances play important roles in dento-maxillo-facial development. Deficiency or over-function of the endocrine glands is associated with disturbances in dental development, eruption and jaw growth, although no specific endocrinopathy is productive of a pathognomonic malocclusion. Prevention. Recognition of etiologic factors is important in the prevention, interception and treatment of dento-maxillo-facial anomalies. Prevention is the basic approach to ‘public health’ orthodontic endeavor. As long as we do not possess definitive knowledge of the etiology of malocclusion, we are limited in instituting preventive measures. However, present knowledge is sufficient to prevent and intercept much of the existing malocclusion. Orthodontic principles and prevention are important in every phase of dental practice, whether it be filling teeth, restoration of lost teeth, space maintenance and removal of overlong retained deciduous teeth, or treatment of the soft tissues of the mouth. The dentist must possess knowledge of normal growth and development of the teeth, jaws and face, and their deviations in order to institute proper measures to obviate the development of malocclusion. Examination of the young child must be made at periodic time intervals using diagnostic aids which lend themselves to comparative analysis of the individual child and not necessarily to arbitrary or ‘average’ standards. Eruption, migration, and physiologic readjustment of the teeth, oro-dental pressure habits, and increase in jaw size and in the tonicity of the masticatory and mimetic musculature must be given due consideration. Thumbsucking is considered a normal activity in infancy and usually disappears about the second year of life. If persisted in later years it is a symptom of emotional disturbance. Treatment involves the pediatrician, psychiatrist, dentist, child and parents. Force is contra-indicated. Nailbiting and ‘open-bite’ swallowing are among the habits responsible for malocclusion. Parents should be encouraged to establish a kindly cooperative relationship rather than be asked to ‘police’ habit breaking with its engendered tensions. Space maintenance is not the simple procedure as usually practised. The entire dentition and the developing occlusion must be taken into consideration.
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Apr 2, 2021
William Timothy Treal Taylor + 1
Open Access
