Mouthguards and splints: explained

Mouthguards and splints: explainedNick Coller breaks down the merits of the humble mouthguard – a simple appliance, but when done well, one with a host of indications.

Mouthguards coverings used over the teeth protect the hard and soft tissues of the mouth from sports injury, or worn at night to counter the effects of clenching and grinding, sleep apnoea and snoring.

There are several types of mouthguard available.

Stock mouthguards

Stock mouthguards are preformed mouthguards usually bought in sports shops. Worn on the maxillary arch and designed for use without any modification, they must be held in place by clenching the teeth together to provide a protective benefit (CDHA, 2005).

Mihalik et al (2007) highlighted that ‘they cannot be prepared to mimic the mouth, they fit poorly and look bulky’. Clenching a stock mouthguard in place can also ‘interfere with breathing and speaking’ (CDHA, 2005). Stock guards are thus considered to be less protective in nature compared to other forms of mouthguard (especially custom made).

Boil-and-bite mouthguards

Made from thermoplastic material, boil-and-bite mouthguards can be customised to the user’s teeth. This is done by placing the guard into boiling water until it softens and then placing it over the maxillary teeth and biting down.

However, boil-and-bite mouthguards tend to be thinner than custom-made mouthguards. One should therefore take care that they don’t bite through.

Custom-made mouthguards

Prescribed and custom-made by a dental professional, custom-made mouthguards provide a personalised fit to the patient’s dentition, making them more comfortable and harder to accidentally dislodge when sleeping or playing sport.

Uses of mouthguards and splints:

Dental/orofacial trauma prevention

Gum shields were originally developed in 1890 by Woolf Krause, a London dentist, as a means of protecting boxers from lip lacerations. They are still highly recommended for those who play contact sports (such as rugby and boxing) or sports where there is a high risk of injury to teeth and other structures of the mouth (such as skateboarding).

As Mantri et al (2014) noted: ‘The mouth guard acts as a buffer by moving the soft tissues in the oral cavity away from the teeth preventing lacerations, bruising of lips, cheeks, and tongue during an impact.

‘It is supposed to prevent tooth fractures or dislocations by cushioning the teeth from direct frontal blows while redistributing the force of the blow over all the teeth’.

Concussion prevention

Limited evidence shows that sports guards can assist in concussion prevention. Nonetheless, Stenger et al (1964) highlighted that ‘with a mouth guard in situ, there was an altered mandibular position on lateral skull radiographs, so that the condyles were distracted from their fossae’.

In contradiction however, Scott et al (1994) concluded that, ‘mouth guard use does not result in any difference in neurocognitive test performance after concussion’.


Wearing guards and splints can manage a number of sleep-related conditions.

After an initial stage of adaption where the patient might feel self-conscious wearing the device at night in the presence of a partner or experience temporomandibular joint soreness or dental soreness, most patients find little issue wearing a nightguard. Indeed, in the case of sleep apnoea and snoring, such guards afford an alternative to continuous positive airway pressure treatment, which many patients find hard to adapt to.

Nonetheless, sleep-related guards and splints do have some notable disadvantages. These include:

Tooth movement (normally noted in the first two months of wearing the guard) (Sutherland et al, 2014)

Change in dental occlusion or in jaw relations

Excessive salivation.

Sleep bruxism

Bruxism is a movement disorder of multifactorial aetiology, characterised by grinding and clenching of teeth when the individual is not chewing or swallowing. Bruxism can lead to a variety of issues including tooth damage and jaw pain.

Some believe that night guards and occlusal splints help in the management of the signs and symptoms of bruxism, rather than treat its causes (Behr et al, 2012; Dao and Lavigne, 1998). Such splints can help guide movement, reduce tooth damage and tone muscle.

Made from hard or soft material, the splint usually covers all of the maxillary or mandibular teeth.

Hard night guards normally get prescribed for severe bruxers. This is because they are more durable. Further, one should note that soft splints potentially increase clenching behaviour in some patients (Lal and Weber, 2020).

Sleep apnoea

Obstructive sleep apnoea (OSA) is a condition of multifactorial aetiology. It’s caused by partial or complete obstruction of the airway while sleeping. This can lead to a drop in oxygen levels in the blood circulating around the body (Lal and Weber, 2020).

For those with mild sleep apnoea, a custom-made mandibular advancement splint is available to push the lower jaw and tongue forward, thus keeping the airway open.

However, Sutherland et al (2014) noted that: ‘Sleep apnoea devices are not efficacious for all, with approximately one-third of patients experiencing no therapeutic benefit.’


Vibrations of soft tissue in the upper airway causes snoring. Indeed, habitual snoring can also be a symptom of OSA.

Anti-snoring devices tend to work like those for sleep apnoea; pulling the lower jaw forward to keep the airway open.


Stock and boil-and-bite mouthguards are relatively inexpensive and are favoured by those playing sports. However, such guards do not tend to fit effectively and therefore often fall out or the user takes them out due to discomfort. This evidently greatly reduces the protection they afford.

While more expensive, custom-made guards afford greater comfort and fit. However, they cost more as they are in a laboratory.

Custom-made guards provide superior protection for those playing sports as well as being the go-to type of guard for bruxism, sleep apnoea and snoring.

Guards for night time use often require an initial period of user adjustment. In one third of cases, a guard for sleep apnoea is non-effective, offering no therapeutic benefit (Scott et al, 1994). 


Behr M, Hahnel S, Faltermeier A, Bürgers R, Kolbeck C, Handel G (2012) The two main theories on dental bruxism. Ann Anat 194: 216-9

CDHA (2005) CDHA Position paper on sports mouthguards. Canadian Journal of Dental Hygiene 39(6): 1-18

Dao TT, Lavigne GJ (1998) Oral splints: the crutches for temporomandibular disorders and bruxism? Crit Rev Oral Biol Med 9: 345-61

Lal SJ, Weber KK (2020) Bruxism management. [Updated 6 Feb 2020]. Statpearls Publishing (internet)

Mantri SS, Mantri SP, Deogade S, Bhasin AS (2014) Intra-oral mouth-guard in sport related oro-facial injuries: prevention is better than cure! J Clin Diagn Res 8(1): 299-302

Mihalik JP, McCaffrey MA, Rivera EM, Pardini JE, Guskiewicz KM, et al (2007) Effectiveness of mouthguards in reducing neurocognitive deficits following sports-related cerebral concussion. Dent Traumatol 23(1): 14-20

Scott J, Burke FJ, Watts DC (1994) A review of dental injuries and the use of mouthguards in contact team sports. Br Dent J 176(8): 310-14

Stenger JM, Lawson EA, Wright JM, Ricketts J (1964) Mouth guards: protection against shock to head, neck and teeth. J Am Dent Assoc 69: 273-81

Sutherland K, Vanderveken O, Tsuda H, Marklund M, Gagnadoux F, Kushida C (2014) Oral appliance treatment for obstructive sleep apnea: an update. J Clin Sleep Med 10(2): 215-227


Nick qualified with an MA (Oxon) from St Catherine’s College Oxford, in French and German. He worked for 10 years in marketing, communication and business strategy before changing careers into dentistry. He received the Tutor’s Award from King’s College Hospital where he studied a Diploma in Dental Hygiene and Therapy. Nick was recently accepted as the first UK hygienist to qualify as a hygieniker (senior hygienist) in Hessen, Germany.

Nick currently works across a variety of specialist private and mixed practices in central and south west London. He also runs his own facial aesthetics business, and is a passionate writer and oral health educator.

This article first appeared in Oral Health magazine. You can read the latest issue here. 

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