HSC Section 3 - Trauma, Critical Care and Sleep Medicine

effects described are muscle and joint disorders, changes in salivation, and occlusal changes.

a significantly higher decrease in AHI was observed with the monobloc appliance. This agrees with the stud- ies of Tsuiki et al., 2 Chan et al., 37 and Poon et al. 36 Both devices increased the upper airway dimensions. As regards the effectiveness of MADs in relation to the airways and orofacial muscles, a number of authors have observed that MADs increase airway size. 2,37,40,41 However, the methods they employed vary considerably. Brown et al. 40 found that in the patients whose AHI decreased, a widening of the upper airway accompanied by posteroanterior movement of the tongue took place during mandibular advancement. Tsuiki et al. 2 obtained similar results. Using nasopharyngoscopy, Chan et al. 37 observed an increase in the dimensions of the velophar- ynx. This increase was greater in patients whose AHI fell by > 50%. These authors considered that nasophar- yngoscopy could be useful for predicting the outcome of treating OSAHS with an MAD and improving the selec- tion of patients for this type of treatment. Kurtulmus et al. 41 observed a significant increase in the electromyo- graphic amplitude of the masseter and submental muscles and concluded that activation of these muscles during sleep prevents airway closure. Most of the articles reviewed agree on the short- and long-term adverse effects caused by MADs. Marklund and Franklin 42 observed increased salivation, dry mouth, bad taste, and occlusal changes, which were greater in the patients who had been using a MAD for longer. Zhou and Llu 39 also recorded ulcers, joint pain, muscular pain, and tooth discomfort. Lawton et al. 3 observed a decrease in adverse effects after 4 to 6 weeks of use. Twin Block users reported less muscle and joint discomfort than those using the Herbst device. Similarly, Giannasi et al. 30 stated that the adverse effects did not persist for more than 3 months. Martinez-Gomis et al. 43 did not find any temporomandibu- lar disorders in a 6-year longitudinal study, but did find a significant decrease in overjet, overbite, and the number of posterior occlusal contact points, coinciding with the findings of Doff et al. 44 In relation to the advancement achieved, Aarab et al. 10 observed that the side effects rose considerably from 50% protrusion onward, but the lowest AHI results were obtained with 75% protrusion. As regards the material from which the device is made, some authors have found that acrylic MADs pres- ent frequent problems such as breakage of the acrylic or the wires. 44,45 Ash and Smith 45 observed that chrome- cobalt devices afforded greater retention, stability, and patient acceptance and were also kinder to the soft tissues. MADs do not eliminate sleep apnea completely but they do reduce the AHI to levels that may be considered mild and they do increase oxygen saturation. Regarding the criteria for successful treatment with MADs, defini- tions of treatment success in reports of MADs efficacy also vary. For the present review, the studies in which the AHI fell by 50% or fell from moderate to mild were considered successful. 26 Of the 18 articles that studied the effective- ness of MADs in reducing the sleep AHI, 16 met this crite- rion of success. Moreover, the MADs presented few side effects, good acceptability compared to CPAP, and an

DISCUSSION The evidence collected on using MADs to treat OSAHS was not abundant, as the rigorous selection of methodologically acceptable articles of medium or high quality limited the number of articles included in this systematic review. On comparing the effectiveness of fixed and adjusta- ble MADs (Tables I and II), Lawton et al. 3 observed that the Twin Block (a fixed MAD) and the Herbst (an adjust- able MAD) were equally effective in improving AHI, snor- ing, and oxygen saturation but that the Herbst appliance gave better results for daytime sleepiness. These results coincide with those of Itzhaki et al., 28 who also found improvements in daytime sleepiness with the Herbst appliance. Lettieri et al. 23 obtained satisfactory results with both adjustable and fixed MADs, but the adjustable type gave a greater reduction in AHI and improvements in ESS in a greater number of OSAHS patients. Tsuiki et al. 2 used adjustable MADs and observed a lowering of the AHI in all the patients and an improvement in mini- mum oxygen saturation. Similar results were obtained by Giannasi et al., 29,30 who also noted that adjustable MADs gave a greater reduction in daytime sleepiness and in snoring than the rigid appliances. Duarte et al. 31 also observed the effectiveness of treating patients with adjustable MADs. In this case the device was inserted at a maximum protrusion of 60%, applying 0.5- to 1-mm increments every 2 weeks. Banhiran et al. 32 found a sig- nificant reduction in AHI in 60.9% patients with AHI < 5 (of whom 75% presented moderate OSAHS). These authors used adjustable MADs and applied 0.5- to 1-mm increments every 1 or 2 weeks for 4 to 6 months. In addi- tion to all the above effects, Naismith et al. 33 stated that MADs improve the individual’s reaction time and psycho- motor component, as well as the subjective perception of sleepiness and fatigue levels. In comparisons of custom-made and prefabricated MADs (Tables I and II), Vanderveken et al. 34 compared thermoplastic and custom-made appliances in a controlled study. It must not be forgotten that the patient’s discom- fort and noncompliance with the treatment influence the effectiveness of prefabricated MADs more than that of custom-made appliances. Also, the mandibular advance- ment is greater and better controlled with a custom-made MAD. Dieltjens et al. 35 obtained the same results and, additionally, an improvement in snoring and daytime sleepiness. Poon et al. 36 found a significant improvement in AHI and oxygen saturation with prefabricated MADs, and also an increase in airway space at the nasopharyn- geal level, although not in the velopharynx, contrary to the findings of Tsuiki et al. 2 and Chan et al. 37 Ghazal et al. 38 studied two custom-made MADs. Both improved daytime sleepiness and sleep quality after 6 and 24 months, but the Thornton Adjustable Positioner appliance achieved a higher success rate than the IST device. Zhou et al. 39 compared a duobloc and a monobloc MAD. Both improved sleepiness and snoring levels, but

Laryngoscope 126: February 2016

Serra-Torres et al.: Oral Appliances for Sleep Apnea

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