Introduced by Newell in 1912. The oral screen is used for the correction of the following conditions:-1. Thumb sucking, lip biting and tongue thrust2. Mouth breathing3. Mild distoclusions with premaxillary protrusion and open bite in deciduous and mixed dentition.4. Flaccid orofacial musculature.
Mechanism of action If the upper incisors are proclined and spaced and there is an increase in overjet and the oral screen is made so that it touches only the proclined incisors and is not in contact with the teeth in the buccal segments, the pressure of the lips and cheeks which lie in contact with the smooth divergent lateral wings of the oral screen will all be concenterated on the labial surfaces of the proclined incisors near the incisal edges. Oral screen also keeps the perioral musculature away from exerting its force during functional movements on the buccal aspect of posteriors. The lingual force (tongue) acting on the posterior teeth is no longer counteracted by forces of perioral musculature resulting in buccal drifting of posteriors or the expansion of arches.
In a Mixed dentition Class II, Divison I type malocclusion with mouth breathing are often associated with excessive epipharyngeal lymphoid tissue. A vestibular screen may prove to be a psychological hazard in those cases. As nasal breathing seems difficult, small holes ( 3 small holes) may be made in the screen, as recommended by Krauss.
These are cut in the appliances when it is first given to the pateint and the holes may be gradually reduced in size with acrylic as the patient becomes accustomed to the wearing of the appliance GRABER AND NEUMANN Removable Orthodontic Appliances
Difference between oral screen andvestibular screen Krauss limited the term “oral screen” to those appliances with the objective of controlling tongue function. In his version of the vestibular screen, the material extended into the vestibule in contact with the alveolar process but did not touch the teeth at all. Other variation of Krauss is the combine oral and vestibular screen to make a “double oral screen” for eliminating mouth breathing, tongue thrusting, and dental protrusion. GRABER AND NEUMANN Removable Orthodontic Appliances
Adenoidectomy Hypernasality occur after removal of adenoids from children whose soft palate is insufficent to close the nasopharynx during speech Injury to eustachian tube opening. Nasopharyngeal stenosis Logan Turner’s Disease of the Nose, Throat & Ear 10th edition