Special Forms of Splint Therapy
Respiratory disorders with partial or complete displacement of the upper airways during sleep are associated with snoring noises that arise from vibration of the soft palate (Figs 11-28 and 11-29). Snoring is normally not harmful to health and does not require treatment. However, health may be impaired if respiratory arrest occurs for more than 10 seconds, despite breathing effort, because the upper airways are displaced. This arrest causes a decrease in oxygen saturation of the blood and triggers a waking reaction (Fig 11-30). Depending on the severity of this disorder, such respiratory arrest events followed by a waking reaction may occur between 5 and 40 times an hour (up to 100 times a night).The repeated waking reactions and interruption of sleeping phases cause increased drowsiness during the day. This condition is known as obstructive sleep apnea (OSA).
Snoring is a sign of this condition if it happens constantly and not sporadically. Sufferers are older, usually overweight adults. Abnormal anatomical proportions in the area of the upper airways may also be responsible for airway displacement, such as a long soft palate, an extended root of the tongue, or a mandibular dental arch that is too narrow.
Treatment of particularly severe OSA cases involves positive pressure ventilation during sleep or surgical measures. Less severe cases can be treated with intraoral appliances that keep the upper airways open.These appliances include:
- Tongue retainers to pull the tongue forward
- Appliances to lift the soft palate
- Occlusal splints to pull the mandible forward
Tongue retainers are hollow bodies that encompass the tongue like a low-pressure chamber and hold it in an anterior position. As well as the body of the retainer, breathing tubes are attached. The retainer is fitted to the dentition and lies passively in the mouth.
Appliances to raise the soft palate are palatal plates fixed to the teeth with Adams clasps, and they carry a pelotte (a small, specially designed curved plate) on a spring loop. As a result, the soft palate is gently pressed upward, and snoring is prevented. The appliance is unsuitable for patients who exhibit a gag reflex to the appliance and is ineffective as a treatment method in OSA.
Anti-snoring mouthpieces are occlusion rims that pull the mandible downward and forward to widen the airways (Fig 11-31). The opening width and the protrusive position are determined individually and connected in a fixed-value device (mandibular protrusive splint). Split occlusion rims can also be fabricated with which the most effective protrusive position can gradually be found and adjusted.
An anti-snoring mouthpiece can be made in the form of two thick vacuum-formed sheets that are anchored to the teeth by a tight fit. They are connected via screws, linking arms (adjustable), or by a rigid acrylic block (fixed appliance). A rigid mouthpiece may also comprise a silicone block that holds the advanced mandibular position; it can be fabricated by the dentist directly in the mouth.
Aligners are transparent orthodontic splints, spring wires, or screws. Correction of tooth position is accomplished with a series of removable acrylic splints that initiate individual regulating thrusts. The initial orthodontic status is recorded three-dimensionally and developed in separate phases by computer-aided design technology, or even an analog technique, until the treatment objective is achieved. Individual splints to be worn for about 2 weeks are prepared in small correction steps. Orthodontic tooth movement occurs during this period, and the next modified splint is inserted until the projected treatment goal is attained.The splints are designed so that individual regulating thrusts are applied with defined force within the second level of biologic intensity and for a defined period of time. Different teeth or groups of teeth defined in the treatment plan are moved in each treatment phase. Therefore, long enough recovery phases for tissue adaptation are maintained before the next regulating thrust takes place.
Aligner splints are worn day and night, but they can be taken out to allow unimpeded eating and drinking as well as cleaning. They are transparent and therefore invisible, and they function without wires so that there is no rubbing on the teeth.The wearing characteristics are good, without longterm phonetic impairment. Wearers must maintain thorough oral hygiene.
The Drum Miniplast splint is a removable, universal occlusal splint that is made from a transparent 0.5- to 2-mm-thick vacuum-formed sheet for both the mandible and the maxilla. The term Miniplast splint can be regarded as a nonspecific synonym for a dental splint with a wide variety of treatment objectives.
Modified forms of the Miniplast splint can be described in relation to the specific application:
- A smooth, thick vacuum-formed splint that is not ground in is used as a bruxism splint to remove parafunctional movements.
- A thick vacuum-formed splint that is ground in centric occlusion aims to achieve a splinting effect and serves as a relaxation splint to reduce muscle tone.
- A thick vacuum-formed splint reinforced with biting surfaces that are based on a construction bite can compensate for faults of occlusal position.
- A thin, elastic vacuum-formed splint can be used as a carrier splint for a gel to bleach the teeth or can be coated with fluoride gel for fluoridation of the teeth.
- A thick, stiff vacuum-formed splint can be used to stabilize teeth loosened after trauma or gingival treatment (Fig 11-32).
- A thick vacuum-formed splint that encompasses both dentitions and is reinforced with elastic material acts as a mouthguard to protect against sports injuries.
- A stiff vacuum-formed splint that encompasses both arches and offers fixation can be used to stabilize the tooth position after an orthodontic measure; this splint can be interpreted as a positioner or retainer.
Retainers are used after an active orthodontic treatment phase to maintain the corrected tooth position until restructuring of the tissues affected by the orthodontic measures is completed. No teeth are moved any further in this treatment phase, which is known as the retention phase because it is intended to stop a return (recurrence or relapse) to the malposition of the teeth. If the retention period, which is almost as long as the active treatment period, is not adhered to, a relapse may occur and further treatment may become necessary. In extreme cases, lifelong retention will be required. After treatment with multiband appliances, the retention phase generally lasts longer. Retainers are rigid, thin, transparent acrylic plates that lie against the teeth lingually, are retained by an archwire running in the vestibular area, and permit unimpeded intercuspation. They should be worn all day; they do not interfere with phonetics and are almost invisible due to the clear plastic.
Lingual retainers or bonded retainers are fixed appliances that consist of a flexible wire that is fixed to the lingual surfaces by plastic adhesive. They are preferably inserted in the mandibular anterior region because the risk of relapse is greatest there. After treatment with removable appliances, the last appliance can be used as a retainer; none of the activatable parts (screws, springs, bars) are readjusted any further.
Mouthguards are intended to reduce injuries during contact and strength sports and are constructed or designed in keeping with the type of sport or the nature of the anticipated physical contact.The mouthguard can be fabricated in several layers; a hard base layer, extending over the whole palate and covering all the teeth occlusally, lies between two acrylic layers that remain soft and fit closely to the teeth and jaws. The vestibular pad is applied to a thickness of 9 to 10 mm and extends into the vestibular fornices.
The term positioners denotes appliances that are made of elastic material and, where necessary, still allow fine correction of tooth position. After completion of treatment, the dental arch is sawn apart on the individual model, and the m od el teeth are pl aced i n the i deal posi ti on. An elastic vacuum-formed splint is pulled onto this setup and represents this ideal position. The patient's teeth are gently pushed into the final position. After fine correction is performed with the positioner, a retainer is inserted that fixes the final tooth position.