PubMed · 6932895
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M A Burley. 1980-10-21. The activator.. https://doi.org/10.1038/sj.bdj.4804494
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The mode of action of the activator appliance is still unclear. Apart from a possible mandibular growth enhancing effect, some investigators believe that orthopedic forces may be applied to the maxilla, contributing to Class II correction by inhibition of maxillary growth. In addition, orthodontic forces may arise that produce dentoalveolar changes. The purpose of this study was to measure the magnitude of anteroposterior intermaxillary forces during wear of the activator appliance. Ten consecutive patients with Class II dental and skeletal relationships were treated with a modified activator appliance. The appliance had maxillary and mandibular segments that could be detached from each other during the measuring session. A force transducer was placed at the anterior part of the maxillary segment, and the anteroposterior force exerted by the mandibular segment was measured. Measurements were taken in the upright and reclined position at every patient visit for a period of 6 months. Results indicated that intermaxillary forces were generally in the orthodontic range (median values of 100 gf at the upright position and 123 gf at the reclined position). A wide variation in force levels was noted, both between patients and for the same patient during the experimental period. No statistically significant change in force levels was observed during the 6 month period and no difference was noted between upright and reclined posture.
Anterior mandibular positioning devices are seldom used at present in the treatment of obstructive sleep apnoea syndrome (OSAS). The aim of our study was to evaluate the efficiency, the side-effects and the patient compliance with one type of device made in Switzerland, the Serenox. This device is designed to keep the mouth closed with the mandible forward, avoiding the vibration of the soft palate. Between January 1996 and October 1997, 15 patients with OSAS were treated using a Serenox. One of them stopped using the device after 6 weeks due to the persistence of temporomandibular joint pain. Serenox was successful in 13 of the remaining 14 patients. The median pretreatment apnoea/hypopnoea index (AHI) of 36.25/h was decreased to 5.5/h after treatment (P < 0.002). Snoring and daytime sleepiness were notably reduced. The side-effects were frequent but mild and disappeared after a few weeks of adaptation. In conclusion, 87% (13/15) of the patients were treated successfully. Indications for the use of a mandibular positioning device include snoring, upper airway resistance syndrome and light to mild OSAS without severe obesity.
OBJECTIVE: The present study was undertaken to document whether mandibular length could be increased by distraction osteogenesis in children and what happens to the mandibular position 1 year after the distraction. METHODS: Five patients with hemifacial microsomia (four unilateral, one bilateral) had distraction osteogenesis performed to lengthen the mandible. All patients had cephalometric and panoramic radiographs obtained before and 3, 6, and 12 months after the distraction osteogenesis. RESULTS: The total mandibular length (Co-Gn) on the affected side was increased by 11.2 mm after the distraction and remained stable during a 1-year observation period. However, the increased mandibular length tended to move the chin downward (8 mm) more than forward (2 mm) during the same period. CONCLUSIONS: Distraction osteogensis can be used to lengthen the hypoplastic mandible. However, most of the increased mandibular length moved the chin downward more than forward.