Effects of the mandibular protruding device
Fransson AM, Kowalczyk A, Isacsson G. A prospective 10-year follow-up dental cast study of patients with obstructive sleep apnoea/snoring who use a mandibular protruding device. Eur J Orthod 2017;39:502-8
Patients suffering from obstructive sleep apnea seek treatment from their physician. The most commonly recommended treatments are continued positive airway pressure, mandibular advancement device (MAD), and mandibular protruding device (MPD). The MPD is recommended by American College of Physicians as an alternative therapy for those who suffer adverse effects from continuous positive airway pressure or the mandibular advancement device. Even though MPDs can lead to significant improvement in sleep apnea and snoring, previous studies have shown adverse dentoskeletal effects. The aim of this prospective observational study was to measure and evaluate the positions of teeth and occlusion on dental casts after 10-year nocturnal use of MPDs in subjects with OSA or snoring. For this study, 77 subjects diagnosed with obstructive sleep apnea or snoring were treated with an MPD. These subjects had enough teeth to retain the device and good dental health. Dental casts with jaw registration at maximum intercuspation were fabricated. The MPDs were made with heat-cured methyl methacrylate resin (Microdent, Forshaga, Sweden). The mandible was positioned a minimum of 5 mm forward and as much as 75% of maximum forward position. The MPD was designed as a monobloc appliance with full occlusal coverage. At the 10-year follow-up, 60 of the 77 participants returned; of them, 41 still used the MPD, and 19 had discontinued using it. Analysis of casts obtained at the 10-year follow-up showed significant decreases in overjet (1.8 mm) and overbite (1.5 mm) in the MPD users compared with minimal decreases in ovejer (0.3 mm) and overbite (0.6 mm) in those who had ceased usage. The MPD users also demonstrated increased posterior infra-occlusion and mesio-occlusion of the mandible. The authors concluded that long-term use of MPDs can adversely affect occlusion mostly in the anterior region (by reducing overjet and overbite) and in some cases may lead to posterior infra-occlusion. They also suggested that Class III patients may not be suitable for MPD usage because of the potential for mesial drift of the mandibular teeth.
Reviewed by Pardis Parizadeh
Timing of expansion treatment
Masucci C, Cipriani L, Defraia E, Franchi L. Transverse relationship of permanent molars after crossbite correction in deciduous dentition. Eur J Orthod 2017;39:560-6
The purpose of this retrospective study was to evaluate the effects of the correction of posterior crossbites during the deciduous dentition with 2 expansion protocols on the transverse relationships of the permanent first molars in the mixed dentition. Ninety patients (40 boys, 50 girls) with posterior unilateral or bilateral crossbite in the deciduous dentition were selected from 5000 patients treated at the Unit of Orthodontics of the University of Florence in Italy from 1975 through 2014. Sixty patients were treated with a removable expansion plate, and the remaining 30 were treated with a rapid maxillary expander. Dental casts were evaluated at pretreatment (mean age, 5.1 ± 0.7 years) and posttreatment (when the permanent first molars were fully erupted (mean age, 7.7 ± 1.0 years). The prevalence rates for posterior crossbite on the permanent first molars in the 2 groups were compared with the chi-square test with the Yates correction. At posttreatment, 34.4% of the patients demonstrated posterior crossbites on the permanent first molars: 28.3% in the removable expansion plate group and 46.6% in the rapid maxillary expansion group. No significant predictors for the “presence/absence of posterior crossbite on the first permanent molars” at posttreatment were found, even when evaluating sagittal skeletal relationship or sex distribution or posterior transverse interarch discrepancy. The authors recommended that expansion treatment should be delayed until after the permanent first molars had fully erupted.
Reviewed by Inessa Kandov
Timing of expansion treatment
Masucci C, Cipriani L, Defraia E, Franchi L. Transverse relationship of permanent molars after crossbite correction in deciduous dentition. Eur J Orthod 2017;39:560-6
The purpose of this retrospective study was to evaluate the effects of the correction of posterior crossbites during the deciduous dentition with 2 expansion protocols on the transverse relationships of the permanent first molars in the mixed dentition. Ninety patients (40 boys, 50 girls) with posterior unilateral or bilateral crossbite in the deciduous dentition were selected from 5000 patients treated at the Unit of Orthodontics of the University of Florence in Italy from 1975 through 2014. Sixty patients were treated with a removable expansion plate, and the remaining 30 were treated with a rapid maxillary expander. Dental casts were evaluated at pretreatment (mean age, 5.1 ± 0.7 years) and posttreatment (when the permanent first molars were fully erupted (mean age, 7.7 ± 1.0 years). The prevalence rates for posterior crossbite on the permanent first molars in the 2 groups were compared with the chi-square test with the Yates correction. At posttreatment, 34.4% of the patients demonstrated posterior crossbites on the permanent first molars: 28.3% in the removable expansion plate group and 46.6% in the rapid maxillary expansion group. No significant predictors for the “presence/absence of posterior crossbite on the first permanent molars” at posttreatment were found, even when evaluating sagittal skeletal relationship or sex distribution or posterior transverse interarch discrepancy. The authors recommended that expansion treatment should be delayed until after the permanent first molars had fully erupted.
Reviewed by Inessa Kandov
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