snoring is caused by vibration of the soft tissue during sleep while breathing within extrathoracal respiratory tract .
pathological reasons for the noise include tension loss in the oropharyngeal muscle due to disturbed innervation , degenerative processes , tumours , and changes in the mucous membranes .   in general ,
the snorer 's sleep profile and the cardiovascular situation are undisturbed , thus snoring does not affect a snorer 's general health situation , but it can significantly impair social life and marital relation .
if , in addition to snoring , the patient complains about clinical symptoms such as excessive daytime sleepiness , reduced efficiency , morning headache , high blood pressure , and arrhythmias , a sleep - related breathing disorder should be suspected .
this disorder has a considerable and even life - threatening medical impact on a patient 's general health .
the correlation between increased morbidity and morality and moderate and severe expression of obstructive sleep apnoea syndrome has been proved .
therefore , the diagnosis must be made according to a differential diagnostic process . in the west , snoring is a common disorder , with an estimated prevalence of 28% in women and 45% in men in the age average of 30 to 60 years ; approximately 5% of these patients suffer from sleep disordered breathing .
the main risks for a sleep breathing disorder are an increased body mass index , increased age , and male sex .
a family predisposition , hormone status , the anatomy of the extrathoracal airway , the neck circumference and general behavioural factors such as alcohol consumption , use of sedatives , sleeping in a supine position , and a lack of general sleep hygiene can also trigger or cause sleep - disordered breathing .
when women go though the hormonal changes they too have a higher incidence of snoring .   with most patients ,
sleep - disordered breathing is caused by partial or complete obstruction of the upper airways .
in rare cases it can also have centrally - placed source of obstruction . a precise , differential diagnosis is required before the onset of oral protrusive appliance treatment , since these devices are effective exclusively in obstructive sleep apnoea syndrome ( osas ) .
the diagnostic process in osas includes taking the medical history , physical examination , and a cardio - respiratory sleep study . in a cardio - respiratory sleep study , parameters such as the peripheral oxygen saturation and desaturation , pulse , oral and nasal flow , sleep position , paratracheal noises ; occasionally additional parameters are recorded . if cardio - respiratory sleep examination fails to provide a precise diagnosis , polysomnography in a sleep laboratory
this entails an electric encephalogram , so that the cardio - respiratory parameters can be analysed together with the patient 's sleep profile .
oral protrusive appliances are increasingly used in primary snoring and mild - to - moderate obstructive sleep disordered breathing .
an anterior and caudal movement of the mandible during sleep reduces the amount of nasopharyngeal obstructions and snoring in mild to moderate osa considerably .
a mandibular advancement enlarges the pharyngeal airway during sleep thus tightening and stabilising the pharyngeal soft tissue .
adjustment of the mandibular protrusion and pharyngeal opening is anatomically restricted to a certain degree .
described the positive effect of a mandibular advancement device , the so - called esmarch - orthese , on the respiratory situation during sleep for the first time .
the esmarch - orthese is designed like a modified function orthodontic appliance , since it moves the mandible into a protruded and fixed position . to date , other appliances , such as tongue - retaining devices , soft palatinal lifters , and functional training devices have not gained medical acceptance because there is still no adequate scientific proof that these appliances treat snoring and obstructive sleep apnoea effectively .
the mandibular protrusive appliances used for treating snoring and osas vary in their effectiveness , manufacture , material , ability to adjust mandibular protrusion , need of dental retention , durability , wearing comfort , expected side effects , efficacy , and expense ( table 1 ( tab .
the efficacy of two splints appliances fixed on the teeth of the upper and lower jaw has been proved .
the connection system should allow minor jaw movements and can be placed in anterior , buccal , interocclusal or palatinal position within the appliance ( figures 1 ( fig .
there is a vital clinical advantage that the patient can adjust the mandible protrusion himself according to need and his subjective tolerance .
to evaluate the efficacy of oral appliance treatment , parameters such as snoring noise , cardiovascular situation , and daytime sleepiness must be considered .
although oral appliances reduce habitual snoring considerably in some cases , snoring can persist during appliance use cause for this it are body position , alcohol , weight gain , and allergies . the data presented in the literature reveals great divergence regarding the therapeutic effectiveness of oral appliances .
treatment improvement varies from 40% to 83% when one considers the reference parameter rdi ( respiratory disturbance index ) and/or ahi ( apnea -hypopnea index ) .
the difference can be sufficiently explained by different patient selection , inclusion criteria , indications , and the polygraphic and polysomnographic control examinations employed .
oral protrusive appliances affect daytime systolic blood pressure and the diastolic pressure during 24-hour blood pressure recording .
the consistent application of an oral protrusive appliance during sleep reduces those blood pressure values significantly in patients with osas .
there has so far been present no systematically - controlled study examining the specific influence of the treatment modality in affecting in daytime sleepiness and sleep profile .
concerning side - effects caused by oral appliances , we must differentiate between discomfort and long term effects . at the beginning of treatment , patients may complain about increased salivation , tenderness in the masticatory muscle and temporomandibular joint , and occlusion disturbances .
these forces can lead to a retrusion of the upper front teeth and a protrusion of the lower front teeth as well as to an anterior and lateral bite opening .
in general , the extent of dental - side effects depends mainly on the extent of mandibular protrusion , the dental and periodontal situation at the onset of the treatment , and the length of time the appliance is used by the patient .
although side - effects appear frequently during oral appliance treatment ; they are usually mild and clinically acceptable .
if side - effects do occur , continuation of the treatment must be re - evaluated .
two splint appliances covering the entire dental arch of the clinical crowns seem to be superior to those fixed with clamps because of fewer dental side - effects .
dental side - effects can be reduced significantly via functional load on the teeth , e.g. by chewing hard chewing gum . to date , structural changes in the temporomandibular joint by mandibular protrusion during sleep have not been described in the literature .
removable dentures , periodontal diseases , acute infections , temporomandibular dysfunction , as well as epilepsy are regarded as contraindications for this kind of treatment .
a dental based contraindication was diagnosed in about 30% of those patients revered from the sleep - laboratory to a dentist for oral appliance therapy , .
the main advantages of oral appliances are the relative simplicity of the treatment , its non - invasiveness , its reversibility , and cost - effectiveness .
an appliance is easy to transport , to clean and maintain , and it require no electricity . in comparative studies of oral appliances and cpap ( continuous positive airway pressure ) ,
in summary , mandibular protrusive appliances remove or fundamentally reduce snoring 's frequency and volume . prior to initiating oral appliance use ,
however , the presence of characteristic of sleep apnoea syndrome must be examined by performing a sleep study .
oral appliances are indicated in snoring and mild - to - moderate osas only . from the dental point of view , adequate dental anchorage and a healthy stomatognathic situation
is required to guarantee adequate mandibular protrusion during sleep and to reduce dental side effects .
treatment efficacy should be evaluated in regular sleep studies with the patient wearing the appliance .
dental follow - ups are necessary with permanent use to monitor occlusion , the bite , and to ensure correct appliance fit . other less invasive treatment such as better sleep hygiene , positioning training , and weight reduction must be considered to minimise side - effects .
 oral appliances have long been used to treat snoring and mild to moderate obstructive sleep apnoea . 
 this kind of treatment is considered an alternative , non - invasive treatment option . 
 mandibular protrusive appliances enlarge and stabilise the oro- and hypo - pharyngeal airway space by advancing the mandible , and stretching the attached soft tissue , in particular the tongue , soft palate , uvula , and the pharyngeal tissues . 
 this article summarises the indications , contraindications , and possible side - effects of using oral appliances . 
 therapeutic efficacy is influenced by multiple parameters that are clinically difficult to control . 
 one major parameter is the patient`s stomatognathic situation of the patient . 
 thus oral appliances are restricted to patients whose dental retention is adequate for permanent treatment and who do not suffer from temporomandibular joint dysfunction . 
 regular follow - up sleep studies and dental evaluations are necessary to ensure adequate permanent treatment . 
1. Introduction
2. Treatment with oral appliances
3. Efficacy of mandibular protrusion appliances
4. Side-effects
5. Summary