Barbosa RC*, Aloe F†, Tavares SM†§ , Silva AB‡

*Dentistry School , Universidade de São Paulo - São Paulo-SP-Brazil;

†Sleep-Wake Disorders Center, General Hospital, Universidade de São Paulo, São Paulo-SP-Brazil;

‡Department of Neurology, Universidade Federal de São Paulo, São Paulo-SP-Brazil;

§ Sleep-Wake Disorders Center - Hospital Israelita Albert Einstein, São Paulo-SP-Brazil.

Introduction:
The physiologic spectrum of sleep-disordered breathing ranges from partial airway collapse and increased upper-airway resistance manifested as loud snoring and hypopneas to complete airway collapse and episodes of apnea lasting 60 seconds or more. Obstructive sleep apnea syndrome (OSAS), clinically defined by frequent episodes of apneas and hypopneas and symptoms of functional impairment, can be life-threatening and has been associated with extreme daytime sleepiness, automobile accidents and cardiovascular morbity and mortality1. Reports that snoring is associated with stroke, myocardial infarction, and hypertension suggest that even mild degree of sleep-disordered breathing has negative effects. The estimated prevalence of sleep-disordered breathing among middle-aged adults is 2% for women and 4% for men. Therefore, OSAS demands effective treatment. Although nasal CPAP is therapeutically effective, its compliance rate is poor for mild to moderate OSA. In addition to behavioral therapeutic measures (weight loss, position training, alcohol avoidance), the use of removable intraoral appliances has become a treatment alternative for OSAS. The authors report the evaluation of daytime sleepiness measure by Epworth Sleepiness Scale (ESS)2 in 115 OSAS subjects treated with Mandibular-Lingual Repositioning Device - MLRD4 and its relation with BMI and gender.

Methods:
130 patients (106M/24F), BMI range 20.28 to 55.99 (mean=28.14; SD=4.70). All subjects had their clinical diagnosis polissonographically confirmed as OSAS. Two BMI subgroups were created. Group A (n=26; 19M/7F): BMI 19 to 25, normal group3. Group B (n=104; 87M/17F): BMI > 25, overweight group. ESS was applied before and two months after treatment.

Results:
See table.

			Patient	ESS pre		ESS post		SAT O2 min	BMI	RDI
Fem BMI<25			AVG	10,71		3,71		0,87	22,88	16,11
n = 7			SD	4,77		1,98		0,06	1,27	11,54
Fem.BMI>25			AVG	10,82		4,41		0,83	29,91	21,55
n =17			SD	5,72		2,55		0,12	7,22	18,15
Male BMI<25			AVG	14,26		6,32		0,84	23,56	25,78
n = 19			SD	4,11		3,03		0,10	1,34	20,53
Male BMI>25			AVG	14,46		5,70		0,83	29,21	35,92
n = 87			SD	5,57		2,84		0,10	3,70	23,52
ESS variation X BMI and gender					FEMALE		MALE
		BMI<25			65.3%		55.7%
		BMI>25			69.2%		60.6%

Discussion:
The difference in the pre and post-treatment ESS scores for all 130 subjects suggests a reduction in the RDI. In Johns' original work, the mean ESS for controls was 5.9 +-2.2 and their modal was 6. ESS scores significantly distinguished normal individuals from OSA patients and correlated with mean sleep latencies recorded in the MSLT and with the Respiratory Disturbance Index recorded during overnight PSG. In this report, the mean ESS scores for all 130 patients before and 60 days after the MLRD was in use differed in a statistically significant way.

Conclusion:
The subjective daytime sleepiness improvement induced by the oral appliance (MLRD) is generated by a probable reduction in the RDI independently of the BMI and gender.

Bibliography:

1. Young T, Paita M, Dempsey J, Skatrud J, Webber S, Badr S. The occurance of sleep disordered breathing among middle aged adults. N Engl J Med 1993, 328:1230-1235.
2. Johns MW. A New Method for Measuring Daytime Seleepiness: The Epworth Sleepiness Scale Sleep 1991, 14:540-5.
3. Abernathy RP, Black DR. Healthy body weights: Na alternative perspective. Am J Clin Nutr, 63:3 Suppl, 1996 Mar, 448S-451S.
4. Barbosa RC, Aloe F, Tavares SM, Silva AB. Evaluation of daytime sleepiness in 115 subjects treated with Mandibular Lingual Repositioning Device - MLRD. Sleep Res 1996; V.25 p.191.

Current Claim: Dental appliance-induced subjective improvement is generated by a reduction in the RDI independently of BMI or gender.