Full Coverage Mandibular Advancement One-Piece Appliance for the Management of Snoring and Obstructive Sleep Apnea

Abstract

Obstructive sleep apnea (OSA) is a prevalent disorder, marked by recurring partial or complete obstruction of upper airway during sleep leading to oxyhemoglobin desaturation and arousal. Associated symptoms such as snoring, dry mouth, daytime sleepiness, witnessed apneas can lead to social, marital, emotional, and occupational impairment. Oral appliance therapy for such sleep apneas represents a relatively simple alternative for the traditional positive pressure and surgical treatments. This article presents clinical and laboratory steps to fabricate a mandibular advancement one-piece appliance to treat a patient suffering from chronic obstructive sleep apnea .

INTRODUCTION

Obstructive sleep apnea syndrome (OSAS) is characterized by repetitive apnea and hypopnoea that disrupt sleep and cause daytime sleepiness1,2. It is characterized by the absence of airflow in the presence of continuous respiratory effort. This cessation of airflow is related to the anatomic narrowing and collapse of the pharynx during sleep, a situation not encountered when awake because of muscle compensation3. Continuous positive airway pressure (CPAP), introduced by Sullivan et al, has become the standard of care for treating moderate to severe OSA4,5. However, it is not universally tolerated by all the patients because of its bulky nature, noise, air leakage from the mask, noncompliance during travelling and mask being objectionable to the partner6. Oral appliance therapy for sleep-related breathing disorders such as sleep apnea and snoring represents a relatively simple alternative7. Oral appliances attach to the maxillary and mandibular dental arches to protrude and retain the mandible in a forward position. The main objective is to prevent the repetitive collapse of the upper airway during sleep. It has been demonstrated that oral appliances increase upper airway closing pressure, or in other words reduce collapsibility8. This article describes fabrication of a mandibular advancement appliance to treat a case of obstructive sleep apnea syndrome.

CASE REPORT

A forty five year old male patient reported to the Department of prosthodontics, Government Dental College, Trivandrum with chief complaint of loud snoring and intermittent cessation of breathing leading to frequent awakening at night. He also complained of dry mouth and acid regurgitation causing disturbed sleep affecting his psychological and social life. Medical history revealed the problem of sleep apnea since past five years for which he had undergone nasal CPAP therapy. The patient showed poor tolerance to CPAP therapy and a subjective feeling of poor quality of life was noted. He also gave history of allergic rhinitis and frequent episodes of loud sneezing. Extraoral examination revealed a concave profile with class II tendency and a retruded chin. Upon intraoral examination enlarged adenoids and a bulky tongue were noticed. Full complement of teeth was present. Other than mild recession on few anterior teeth, other teeth were apparently normal. Vertical dimension of occlusion ( VDO) and centric relation of the patient were also recorded.

Maxillary and mandibular impressions were made by using irreversible hydrocolloid impression material (Zhermeck , neocolloid). Casts were poured in Type III Dental stone (Elite model, zhermack). Facebow transfer was done to mount maxillary cast onto the Hanau wide vue, semiadjustable articulator. A lucia jig was made with maxillary and mandibular anterior teeth in edge to edge position. The jig was made to deprogramme the muscles of mastication facilitating their relaxation to obtain greater accuracy in record taking. A wax interocclusion record was obtained at the planned protrusive jaw relation position. The mandibular cast was mounted on the articulator using this protrusive record. This is the anteroposterior relationship that was used in the fabrication of appliance. A protrusion of about 5mm was achieved from the centric relation position.

The One-piece mandibular advancement appliance was fabricated in the laboratory using poly vinyl vacuum formed thermoplastic stiff blanks and with the full teeth coverage in both the arches. To increase retention greater palatal extension was given, also the flanges extended till the gingival margins. The appliance had an anterior open space for adequate air flow. The prosthesis was disinfected and inserted in patient’s mouth and the patient was instructed about its use and maintenance. The patient was reviewed after 2 days and 1week, and the prosthesis was evaluated for retention, stability and support. The fit and comfort was found to be satisfactory. Patient complained of mild lower anterior teeth soreness which got resolved in a period of 15 days as the prosthesis was relieved from inner surface. After 2 months the patient revealed decrease in snoring and comfortable sleep without any midnight arousals.

Fig 1 : Preoperative extraoral view	Fig 2 : Preoperative Intraoral view
Fig 3 : Facebow transfer	Fig 4 : Interocclusal records in predetermined edge to edge position
Fig 5 : Advanced position 5mm anterior to centric occlusion position	Fig 6 : Mounting on a semiadjustable articulator
Fig 7 : Vacuum pressed thermoplastic single piece appliance	Fig 8 : Final prosthesis with an anterior window for adequate airflow

DISCUSSION

Obstructive Sleep Apnoea (OSA) is a disorder characterised by repetitive closure of the upper airway during sleep, resulting in sleep fragmentation and nocturnal oxygen desaturation, leading to daytime sleepiness and neurocognitive impairment. Long-term consequences of OSA include increased risk of cardiovascular morbidity and all cause mortality9. As over the last decade oral appliances have emerged as a viable alternative for CPAP therapy. Patients who have had the opportunity to use both treatment modalities often tend to prefer the oral appliances over CPAP10. There are two main types of oral devices used to treat OSAS, i.e those that advance the mandible (MAA) and those that hold the tongue via suction (TRD). Mandibular advancing appliance (MAA) are further of two types i.e those which are custom made for each patient and those which are prefabricated commonly known as “ boil and bite” appliance11. Oral appliances find their greatest success when utilized for simple snoring, upper airway resistance syndrome and mild-to-moderate obstructive sleep apnea. A large literature review by Lowe showed that, as group’s oral appliances were effective in mild-to-moderate OSA with 75% compliance rate12. The advantages of oral appliances over other sleep apnea treatment options include relatively low cost, good success rates, good compliances, rapid effect and being a minimum invasive technique13. Currently, the Centers for Medicare and Medicaid Services requirements for a custom appliance are as follows14:

• Have a mechanism that is hinged or jointed at the sides, front or palate;
• Have a mechanism that allows the mandible to be advanced;
• Are able to protrude the mandible beyond the front teeth at maximum protrusion; and
• Are adjustable by the beneficiary in increments of one mm or less; and
• Retain their adjustment setting when removed.

CONCLUSION

Use of mandibular advancement and tongue retaining devices is a less invasive and effective treatment modality to treat patients suffering from snoring and sleep related breathing disorders. They have a good patient compliance and are especially suitable in those cases where surgical procedures are either contraindicated or not feasible. Though CPAP continues to be the gold standard of care for patients suffering from moderate to severe sleep apnea, oral appliance therapy has proved to be efficacious. In the management of cases suffering from either sleep apnea or snoring, the physician and dentist should come together in providing the most comprehensive and effective treatment to the patients.

REFERENCES