SUMMAR Y Various types of mandibular protrusive appliances have revealed different treatment success in mild-to-moderate obstructive sleep apnoea (OSA). The present study compared the long-term effect of two different appliances in the treatment of OSA. A total of 103 patients with OSA were randomized and treated with an IST Ò or Thornton Anterior Positioner (TAP Ô ) appliance. They were followed-up after a short-term treatment period of 6 months and long-term treatment period of over 24 months. Sleep studies in the sleep laboratory were conducted with and without the appliances, and various questionnaires assessing subjective daytime sleepiness, sleep quality, quality of life and symptom scores were administered at each time interval. Quality of life, sleep quality, sleepiness, symptoms and sleep outcome showed significant improvement in the short-term evaluation with both appliances, but the TAP Ô appliance revealed a significantly greater effect. After more than 2 years of treatment, sleep outcomes revealed an equal effect with both appliances. The subjective benefits achieved initially lessened significantly. This study illustrates that both the IST Ò and the TAP Ô appliances are effective therapeutic devices for OSA after a period of over 24 months. Lack of compliance may be due to insufficient improvement in anticipated subjective symptoms and ⁄ or a recurrence of symptoms over time.

Mandibular advancement appliances (MAAs) are accepted as a treatment option for snoring and mild obstructive sleep disorders. In the present clinical study two differently designed devices were examined for their effectiveness in treating obstructive sleep apnoea (OSA). The study was based on an assessment of 26 patients with a polysomnographic diagnosis of mild OSA [22 men, four women; mean body mass index 27.3 kg/m2 (SD 3.1); mean age 56.8 years (SD 5.2); mean respiratory disturbance index (RDI): 16.0 events/hour (SD 4.4)]. After insertion of the first MAA and a 6-8-week habituation period, a cardio-respiratory home-sleep study was carried out. Following a 2-3-week period with no treatment, the second appliance was inserted. The sequence of the devices was randomized. Once the patients had become accustomed to the second appliance, another somnographic registration was carried out. Daytime sleepiness, snoring, and sleep quality were assessed subjectively on a visual analogue scale. The results showed that a statistically significant improvement in the respiratory parameters was achieved with both appliances (P < 0.01). However, the activator [RDI: 5.5 events/hour, SD 3.3; apnoea index (AI): 3.4 events/hour, SD 2.1] was significantly more effective (P < 0.01) than the Silencor (RDI, 7.3 events/hour, SD 5.3; AI: 5.8 events/hour, SD 3.2). No difference was recorded in the subjective assessment of the therapeutic effects. Both appliances reduced daytime sleepiness and snoring and improved sleep quality, and both influenced the treatment outcome.

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Ultrasound transmission velocity (UTV) in isotropic material as a measure for the modulus of elasticity was correlated to mechanical properties. Changes in micromechanical properties of radiated teeth and influence of the oral cavity were to be evaluated nondestructively. UTV was measured in extracted teeth after 36 Gy and 62 Gy of in situ (enorally, with no contact to the oral cavity) and in vitro irradiation. Relative to controls, teeth subjected to 62 Gy in vivo showed higher UTV values for dentine and enamel. Sound teeth irradiated with 60 Gy in situ also showed higher UTV values for enamel, whereas dentine values were not significantly different from those of control. The mechanical properties of teeth irradiated in vitro were affected only after high experimental doses of up to 500 Gy. The difference between in vivo and in vitro mechanical properties may be due to radioxerostomia-induced damages as well as the status of dentine vitality. This supports the concept of direct radiation-induced damage in synergy with radioxerostomia-induced caries.

A cross-sectional study was undertaken in order to assess the dental age of healthy Southwest German boys and girls between the ages of 2 and 20 years by evaluating 1,003 panoramic radiographs. Dental age was assessed according to the method of Demirjian et al. All permanent teeth of the lower left jaw except the third molar were rated, the development of each tooth was divided into 8 defined stages. Statistical evaluation revealed a correlation between the parameters chronological age and score sum of r = 0.85 for girls and r = 0.89 for boys. The values of the score sum in relation to chronological age were distributed as in a logistic function. Two gender-specific equations for calculating dental age were devised and a marked sexual dimorphism was found. With the beginning of root formation, the girls showed accelerated development. The fact that dental age distribution in Southwest Germany is not significantly correlated to that of a French-Canadian collective underlines Demirjian's demand for regional standards of dental development to be calculated using his score system.