A simplified two-piece mandibular advancement appliance for obstructive sleep apnea

doi:10.4236/ojst.2011.14024

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Open Journal of Stomatology, 2011, 1, 165-167

doi:10.4236/ojst.2011.14024 Published Online December 2011 (http://www.SciRP.org/journal/ojst/ OJST

Published Online December 2011 in SciRes. http://www.scirp.org/journal/OJST

A simplified two-piece mandibular advancement appliance for

obstructive sleep apnea

Hiroshi Ueda1, Masato Ueno2, Genki Watanabe1, Atsushi Horihata1, Teruaki Seo2, Kazuo Tanne1

1Department of Orthodontics and Craniofacial Developmental Biology, Graduate School of Biomedical Sciences, Hiroshima Univer-

sity, Hiroshima, Japan;

2Chugokushiken Dental Laboratory Co., Hiroshima, Japan.

Email: [email protected]

Received 21 July 2011; revised 23 August 2011; accepted 2 September 2011.

ABSTRACT

Nowadays mandibular advancement appliances (MA-

As) are available and distributed widely in the field

of dentistry for the treatment of snoring and ob-

structtive sleep apnea (OSA). However, a few stud-

ies discussed temporomandibular joint (TMJ) discom-

fort and masticatory muscle stiffness during wearing

MAAs are found. A new appliance that we introduced

in this pilot study has shown significant jaw move-

ment and could diminish TMJ and masticatory side

effects.

Keywords: Obstructive Sleep Apnea; Snoring; Mandi-

bular Advancement Appliances; Jaw Movement; Masti-

catory Muscle Stiffness

1. INTRODUCTION

Currently, numerous mandibular advancement applian-

ces (MAAs) are available and distributed widely in the

field of dentistry for the treatment of snoring and ob-

structive sleep apnea (OSA) [1]. It is well known that

MAAs are classified roughly into two different types.

One is one-piece type and the other is two-piece one. Es-

pecially, the latter is widely used to improve temporo-

mandibular joint discomfort and masticatory muscle stif-

fness during wearing MAAs [2]. However, some conven-

tional two-piece type builds in thick springs or tube-and

piston assemblies lingually to the cheeks. OSA patients

may have difficulty tolerating this kind of two-piece MA-

As.

This article is aimed to describe a simplified and com-

fortable two-piece MAA for OSA patients.

2. APPLIANCE DESIGN

Basically, for the most part, the design of oral appliances

for OSA patients is derived from functional orthodontic

appliances to enhance mandibular growth in growing

patients with small and/or distally-located mandible. This

appliance consists of two occlusal splints held together by

an orthodontic wire (Figures 1). The splints are cons-

(a)

(b)

(c)

Figure 1. (a) Mandibular position shifted to the right

with MAA; (b) Mandibular rest position with MAA; (c)

Mandibular position shifted to the left with MAA.

H. Ueda et al. / Open Journal of Stomatology 1 (2011) 165-167

166

tructed of a 0.75 mm thick acrylic resin that provides full

occlusal coverage of teeth. A 0.0175 multi-stranded and

twist wire is attached on the buccal sides of the lower

splint (Figure 2). Patients can connect the lower splint

easily with the hook attached on the front portion of the

upper splint. The initial mandibular advancement was

defined as two-thirds of maximum mandibular forward

position with a 3 - 4 mm vertical opening at the anterior

teeth. This appliance can permit patients to freely move

the jaw horizontally (approximatel y 10 mm in the lateral

direction) and at the same time prevent the mandible to

move downward within 2 mm in the supine position by

means of an optoelectric jaw-tracking system with six

degrees of freedom (Gnathohexagraph system II, Ono-

sokki Co., Yokohama, Japan) (Table 1).

The mandibular position can also be titrated forward

from its initial position by adjusting the wire length on

the appliance.

Figure 2. Upper and lower plates of MAA.

Tab le 1. The distance of mandib ular movement with MAA dur-

ing maximum voluntary effort.

Jaw movement mm

Right-left direction Shift to the right

Shift to the left 11.9 +/– 1.99

11.4 +/– 1.82

Antero-posterior

direction Maximum jaw opening

Lateral jaw movement 1.63 +/– 0.95

0.77 +/– 0.25

(N = 5)

3. CASE REPORT

A 38-year-old male with a chief complaint of sleep frag-

mentation from OSA was referred to our clinic from a

cardiac physician. The patient’s weight, height and BMI

were 73 kg, 171 cm and 25 kg/m2, respectively.

The molar relationship on both sides was Angle’s

Class I, and mild crowding was found in the upper and

lower anterior teeth (Figure 3). Periodontal problems

and tem po romandibular joi nt disorders were not found.

Cephalometric analysis of the patient revealed a ske-

letal class II tendency (ANB = 5.5 degree) with large

mandibular pl ane angle (FMA = 42 degree) (Figure 4).

His apnea-hypopnea index (AHI) was 16.1 (Table 2).

Four months after using the two-piece MAA, the patient’s

initial symptoms were disappeared. Then, the physician

repeated PSG examination with the MAA in use. AHI

after the use of MAA was 9.2, substantially decreased

than 16.1, the initial value. Interestingly, one important

result of this case was the MAA therapy exerted a bene-

ficial effect on cardiac rhythm. This patient reported

much improvement in the number of events of high and

low heart rate according to the heart rate analysis (Table

2). In addition, after the treatment, he has no complaints

of temporomandibular joint pain and myofacial discom-

fort.

Figure 3. An initial occlusion.

Figure 4. An initial lateral cephalogram.

H. Ueda et al. / Open Journal of Stomatology 1 (2011) 165-167

167

Polysomnographic data

Table 2. Polysomnographic results before and after the use of

MAA. permits to move the mandible greatly in the lateral direc-

tion, not so much in the backward direction. Therefore,

undesirable side effects such as temporomandibular joint

disorders and masticatory dysfunction are less during

wearing.

Before After

AHI (/hr)

Hypopnea (/hr)

Obstructive apnea (no.)

Central apnea (no.)

Mixed apnea (n o.)

Min imu m SaO2

Snoring (no.)

Mean Pulse B.P.M.

Number of events of high heart rate

Number of events of low heart rate

16.1

14.5

835

156

143

9.2

8.7

51.4

This appliance is efficient, inexpensive, breaking hardly

and friendly to intra- and extra-oral tissues. A further in-

vestigation focusing on the long-term effect of this ap-

pliance in more OSA patients should be attempted.

REFERENCES

[1] US Food and Drug Administration (1999) Oral devices

cleared for treatment of snoring and/or obstructive sleep

apneas of 1/7/99. Food and Drug Administration, Wash-

ington, DC.

4. CONCLUSIONS [2] Lowe, A.A. (2000) Dental appliances for the treatment of

snoring and/or obstructive sleep apnea. Principles and

Practice of Sleep Medicine, 3rd Edition, M. H. Kryger, T.

Roth, W. C. Dement, W. B. Saunders Co., Philadelphia.

The materials used for the appliance are easy to obtain

and the fabrication is extremely simple. This appliance

APPENDIX Central apnea: absence of airflow due to lack of brea-

thing effort.

Apnea: cessation of ventilation for 10 seconds or longer. Mixed apnea: combination of obstructive and central

apnea with a central pattern evolving into an obstructive

pattern.

Hypopnea: decreased airflow for 10 seconds or longer

and oxygen desaturation greater than 4%.

AHI (/hr): average number of apneas plus hypopneas

per hour of sleep. Minimum SaO2: minimum oxygen saturation level.

Mean Pulse B.P.M.: mean heart rate beats per minute.

Obstructive apnea: absence of airflow despite of per-

sistent breathing efforts.