Influence of Oral Appliances for Mandibular Advancement on Dentitions Using a Strain Gauge Analysis: A Pilot Study.

Introduction. This study aimed to evaluate the influence of oral appliances (OAs) on dentition using a strain gauge analysis. Materials/Methods. Eight volunteers, who were mild snorers, participated in this study. OAs were individually constructed, and advancement was defined as two-thirds of the maximum mandibular advancement. Strain gauges were mounted on the right first molar and central incisor of both the upper and lower arches. After OA use, two measurement sessions (short- and long-term) were performed. Results. Compressive strain on the labial surface was significantly larger than the stretching strain on the lingual surface on U1. On L1, the stretching strain on the labial surface was significantly larger than the compressive strain on the lingual surface. Comparing the upper and lower teeth, the stretching strain was significantly greater on L1 than on U1 in both test sessions. Moreover, the stretching strain was significantly larger on U6 than on L6. Conclusion. OA side effects, such as forcing on the incisors, might be repeated every night. In this way, permanent occlusal changes, such as labial tipping of L1, may occur, followed by lingual tipping of U1 and buccal and lingual movements of the U6 and L6, respectively.

Enhanced increase in pharyngeal airway size in Japanese class II children following a 1-year treatment with an activator appliance.

OBJECTIVE: The aim of this study was to assess the upper airway soft-tissue structures in Class IIJapanese children following activator treatment by means of cephalometric analysis. STUDY DESIGN: A lateral cephalometric radiograph was taken of each patient at Ti (prior to the placement of the activator; mean age: 11 years, 5 months) and T2 (after 1 year of activator treatment; mean age: 12 years, 5 months). Tracings of the lateral cephalometric radiographs were made on acetate paper, and several soft-tissue points and contours of the tongue, soft palate, hyoid, and pharynx were digitised. RESULTS: The sizes of the oropharynx and hypopharynx were significantly smaller in Class II patients than in Class I patients. Moreover, significant differences were observed in the sizes of the tongue and soft palate between Class I and II patients at the age of 12. In terms of the ratio of change relative to the initial values between the 2 skeletal patterns, the width and dimension of the pharyngeal airway in Class II patients showed considerable increases after activator use. CONCLUSION: The pharyngeal airway soft tissue structures of Class I patients using the activator exceeded normal growth after 1 year. This finding suggests that correction ofskeletal Class II discrepancies by the activator in orthodontic treatment could reduce the risk of respiratory problems, such as severe snoring, obstructive sleep apnoea, and excessive daytime sleepiness in the future.

Short-term change in occlusal function after using mandibular advancement appliance for snoring: a pilot study.

The main aim was to evaluate the influence on occlusal contact area (OCA), maximum bite force (MBF), center of occlusal load (COL), and tooth pain after the nocturnal use of different mandibular advance appliances (MAAs) for snoring. Subjects were consisted of ten adult volunteers with mild snoring in Hiroshima University Hospital. Recordings of occlusal function were performed six times for two hours, that is, immediately and 5, 15, 30, 60, and 120 minutes after the nocturnal use of MAA. The subjects continuously scored their pain intensity on a 10 cm visual analogue scale (VAS) when MBF was measured. Comparing two MAAs, OCA and MBF were significantly larger in two-piece MAA than in one-piece MAA five minutes after removing the appliance. Significant difference in COL and VAS score compared to baseline disappeared more quickly with two-piece MAA than with one-piece MAA. In conclusion, it is shown that two-piece MAA could be superior to the one-piece one in terms of the degree side effect on occlusal function.