Night Guards

Dental procedure
Night guards (occlusal guards) help the dental treatment of TMD and bruxism.

Figure 1: Lab-processed acrylic night guards (occlusal guards) are made to be worn over the upper (maxillary) teeth.

Night guards (also called occlusal guards, splints and bruxing appliances) are made of rigid or semi-rigid materials like laboratory-processed acrylic. They are generally made to be worn over the biting surfaces of either the upper or lower teeth, and are easily inserted and removed by the patient.

Night guards accomplish three main functions:

  • Evenly distribute bite forces to protect the teeth from stresses that can crack or wear them abnormally
  • Protect the temporomandibular joints (TMJs) from excessive bite stress that can produce pain, damage to the jaw joint components, and dysfunction
  • Reduce the heavy forces generated by the jaw-closing muscles.
Night guards (occlusal guards) protect teeth and jaw joints.

Figure 2: Front view of the night guard in Figure 1. Night guards protect teeth and jaw joints.

Night guards can prevent damage to teeth and dental restorations, saving the time, expense and potential discomfort of fixing problems that result from clenching the jaw muscles and grinding the teeth (bruxism). They can also be used to treat patients with temporomandibular joint (TMJ) dysfunction and pain (TMD); and people suffering from jaw/facial muscle discomfort and fatigue (myalgia). It is important to understand how night guards work, to decide whether you are a patient who might benefit from the use of night guards.

In the absence of TMJ problems (TMD) or jaw/facial muscle myalgia, is important to establish that a patient has a current bruxism or jaw clenching habit before prescribing a night guard. Patients who have undergone episodes of clenching or grinding their teeth in the past may have teeth that exhibit significant signs of wear. However, they may no longer have the habit. Prescribing a night guard for such a patient may not be helpful, incurring unnecessary cost for the patient and their dental plan.

What else causes tooth wear?

Bruxism isn’t the only cause of tooth wear (attrition). Malocclusion and factitious habits can also cause tooth wear.

Malocclusion is a term for teeth that are poorly aligned don’t mesh properly. Poorly aligned teeth can wear at an accelerated rate even under normal function. If you have this problem, ask your dentist if orthodontic treatment might be an option. Learn more about malocclusion on

Factitious habits is a dental term for using your teeth for purposes other than chewing food. Repeatedly chewing on hard or abrasive objects, biting your nails, grinding sunflower seed husks and other habits like these can accelerate the formation of flattened planes (wear facets) and chips on your teeth. Night guards won’t help with this, but you may need the chipped or worn teeth repaired with bonding, fillings, or crowns. You should try to quit the habit to avoid the re-occurrence of the resulting dental problems. Learn more about factitious habits on

The process

Having a night guard made is easy. Here are the usual steps:

  • The dentist will sometimes have you rest your front teeth on a tongue depressor for a few moments to de-program your jaw closing muscles and allow them to relax. He/she will be able to tell when the muscles are at rest, because it will be possible for the dentist to move your lower jaw for you.
  • Once the dentist can manipulate your lower jaw, they will gently position it into a stable jaw joint position known as centric relation. In this position, they will use any of several materials (e.g. wax, silicone, etc.) to record the position. The selected material will record the position of the upper and lower teeth (interocclusal record), when your jaw is positioned in the centric relation position.
  • Next, impressions will be made of your teeth, and a dental stone material resembling wet concrete is poured into them. When the dental stone hardens, it produces a very accurate replica of your upper and lower teeth, on which the night guard will be made.
  • The stone casts of your teeth will be mounted onto a jaw simulation tool called an articulator, with the teeth positioned correctly using the interocclusal record.
  • A lab technician will use wax to build the night guard on the stone casts. When complete, the wax model will be surrounded with plaster (investing) in such a way that a two-piece mold of the night guard is formed. The wax is then melted out, and a heat-processed acrylic is placed in the mold and allowed to harden.
  • After trimming any sharp edges and polishing the night guard, it is ready to be delivered to the patient.
  • The dentist will make any adjustments to the night guard that may be necessary, and will provide you with instructions on wearing and caring for the appliance. You may or may not require follow-up appointments to adjust the night guard further, depending on the goals of treatment and other factors.
Advantages and benefits

Night guards protect the teeth by evenly distributing the bite forces, and by introducing a sacrificial element for absorption of the bite stress besides tooth structure. They protect the jaw joints (TMJs) from damage, and the jaw muscles from tenderness and pain by reducing the amount of force the closing muscles are able to generate.

How do night guards reduce muscle forces?

If your jaw joints don’t already hurt, and your front teeth are not heavily restored with fillings, crowns, etc., you can try this simple experiment:

Place a tongue depressor (sucker stick) between your upper front four (incisor) teeth. Make sure that only your four front upper and lower teeth (incisors) can touch the stick. Slowly and carefully, start to contract your jaw muscles to squeeze down on the stick. Stop immediately if you feel any pain. Now remove the stick and close your teeth fully together. Again begin to clench your jaw muscles. You should notice that you can develop a lot more muscle contraction force without the stick in between your front teeth than you can with it in there. It may help to place your fingers over the muscles at the corners of your jaws—you’ll be able to feel more of them contracting when your back teeth can touch.

What you have just observed is a phenomenon called proprioception (or nociception), a feedback mechanism from the nerves that surround your incisor teeth, to your brain, that tells your brain not to let your jaw muscles squeeze too hard. A similar feedback mechanism is what gives you the ability to stand up and maintain your balance, only that proprioception system involves your leg muscles and nerves.

Night guards help to reduce muscle contraction forces by placing the front teeth in function the way you just did.

Disadvantages and risks

Disadvantages and risks of night guards include:

  • Night guards can be relatively expensive; however, they are usually less expensive than even one crown, and can protect teeth from fracturing or wearing excessively.
  • Some people find it difficult to adjust to the bulk of an night guard in the mouth; however, they can usually be adjusted enough to make them comfortable.
  • People who wear night guards during waking hours may notice alterations in speech while wearing the appliance, especially at first. If yours will be worn primarily while you’re awake, it may be a good idea to have one made that covers the lower teeth. That way, speaking sounds that involve the tongue will be less affected.
  • Anterior bite plates (a type of night guard that only covers the front teeth) can produce pain in the jaw joints, and are contraindicated in patients already suffering from joint pain or dysfunction. Anterior bite plates are generally indicated only for reducing tenderness in the jaw closing muscles. Even in patients who find relief with anterior bite plates, the device should not be worn more than eight hours per day, or the unsupported back teeth in each jaw may begin to move toward each other (erupt). Then, when the bite plate is out, the front teeth may no longer touch.
  • Night guards may temporarily increase saliva flow when they are first placed into the mouth. This is because your brain thinks they’re food, and initiates the digestive process. This process is generally short-lived, however, and should not impede the ability to wear the device.
  • Pets (dogs in particular) are attracted to night guards, and will quickly destroy them if they get ahold of them.
Other care that may be needed

Night guards are frequently recommended for patients who have had extensive restorative dentistry (e.g. crowns, bridgework, dental implants), to protect the restorations from damage which may have led to problems with the teeth.

Night guards are often recommended when the natural teeth have been worn extensively, to prevent further wear from occurring. Usually, it will be necessary to repair significantly worn teeth with appropriate restorations—to restore them to proper shape and function. Repairing most, or all of the remaining teeth (and replacing missing ones) is known as full mouth rehabilitation. It commonly involves some combination of fillings, crowns, onlays and veneers. Missing teeth may need to be replaced with fixed bridgework or dental implants.

Night guards may also be used as a diagnostic tool, and/or as a temporary solution. For example, the use of a night guard may allow time for a patient to budget for orthodontic treatment or extensive restorative procedures.

Other treatment options
  • Over-the-counter night guards may be effective for some patients. They seldom fit ideally, and may not evenly distribute the biting forces. If they are made of soft materials, the patient may chew on them and actually make their jaw muscles more fatigued. There may be little harm in trying an over-the-counter guard, because they’re usually inexpensive and can be discarded if they aren’t effective.
  • Composite resin filling material can be bonded to the biting surfaces of the teeth in certain patients, to help re-establish the proper bite relationship, provide a wear-resistant surface (full time), lengthen the jaw closing muscles (if needed), and support the jaw joints.
  • Occlusal adjustments (equilibration), which involves adjusting the shape of the biting surfaces of one to several teeth, can improve the way your teeth mesh when your jaws are closed. The goal is to achieve even contacts with the jaw muscles at rest, and the jaws positioned in a relationship that is stable for the jaw joints (balanced occlusion). Sometimes creating a balanced occlusion in this way will eliminate a patient’s bruxing habit. Limited occlusal equilibration normally involves adjusting just a few teeth. Complete equilibration involves adjusting most or all of the teeth. Complete equilibration is generally done on stone casts of the teeth (diagnostic equilibration) to determine how much tooth structure would need to be removed, prior to performing the procedure on the teeth.
  • If excessive wear is developing on some of the teeth due to improper position of the teeth or jaws, orthodontic treatment (tooth movement with braces, aligners, etc.) might be an option.
  • If one of the jaw bones is abnormally large, abnormally small, or abnormally positioned, jaw (orthognathic) surgery may be recommended. Frequently, this will require preliminary or concurrent orthodontic treatment as well. Your dentist can help you understand the indications for surgery, as well as the procedures and timing involved.
What if I do nothing?

Left untreated, a jaw muscle clenching habit can lead to jaw joint dysfunction and pain, The name of the jaw joint is the temporomandibular joint, abbreviated as TMJ. Dysfunction in this joint is typically known as TMD. TMD may also cause cracked teeth, notched teeth (abfractions) and severe jaw/facial muscle pain.

An untreated tooth grinding habit (bruxism) can lead to broken and worn teeth (attrition), broken dental restorations (fillings, crowns, onlays, bridges, etc.); jaw joint pain and dysfunction, and jaw/facial muscle pain.

If the chewing surfaces of the teeth are extensively worn (attrition), it may lead to bite collapse (loss of vertical dimension of occlusion); chapping and cracking at the corners of the mouth (angular cheilitis), reduced lower face height, an “upside-down” smile, and cosmetically unappealing teeth. Ultimately, multiple teeth may be lost, leading to potential problems with chewing and nutrition.

It can cost tens of thousands of dollars to repair the damage caused by a serious bruxing habit.

Author: Thomas J. Greany, D.D.S.
Editor: Ken Lambrecht
This page was reviewed by members of our review board.

This page was last updated on June 3, 2016.

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Related pages on

Abfractions and Abrasions
Abfractions and Abrasions
Cracked Teeth
Cracked Teeth
Dental Implants
Dental Implants
Factitious Habits
Factitious Habits
Fillings and Core Buildups
Fillings and Core Buildups
Loss of Vertical Dimension of Occlusion
Loss of Vertical Dimension of Occlusion
Missing Teeth
Missing Teeth
Removable Dentures
Removable Dentures
TMJ Disorders
TMJ Disorders

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Background information

Occlusion, TMDs, and dental education

Ash, Major M. Jr.

Head & Face Medicine

2007 3 (1)

Photogrammetric Technique For Teeth Occlusion Analysis in Dentistry (PDF, 373K)

Kynaz, V.A. and Zheltov, S. Yu.

Image Engineering and Vision Metrology; International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences

2006: 25-27

Notes: From the Proceedings of the ISPRS Commission V Symposium, Dresden, Germany, 25–27 SEP 2006.

Editor’s notes: This study overlooks two essential elements in the establishment of proper occlusion—resting position of the jaw closing muscles, and stable position of the jaw joints; however, it is included because it presents a viable method of reproducing the stable, resting muscle position once established on the patient. Economic viability of performing the analysis as demonstrated seems questionable.

The treatment of painful temporomandibular joint clicking with oral splints—A randomized clinical trial

Conti, Paulo Cesar Rodrigues, DDS, et al.

The Journal of the American Dental Association

2006 137 (8): 1108-1114

Minimally invasive dentistry

Murdoch-Kinch, Carol Anne, DDS, PhD, and McLean, Mary Ellen, DDS

The Journal of the American Dental Association

2003 134: 87-95

Relationship Between Dental Occlusion and Physical Fitness in an Elderly Population

Takayuki Yamaga, et al.

The Journals of Gerontology, Biological Sciences and Medical Sciences

2002 57: 616-620

Study shows link between antidepressants, bruxism

The Journal of the American Dental Association

2000 131 (3)

Editor’s notes: Article in JADA’s “News” column.

Case Report: Antidepressant-induced bruxism successfully treated with Gabapentin

Brown, E. Sherwood MD, PhD and Sunhee C. Hong, DDS

The Journal of the American Dental Association

1999 130 (10): 1467-1469

Diagnosis and Management of Dental Erosion

Gandara, Beatrice Kay, DDS, MSD and Truelove, Raymond L., DDS, MSD

The Journal of Contemporary Dental Practice

1999 1 (1): 16-23

Dental erosion and bruxism. A tooth wear analysis from South East Queensland (PDF, 177K)

Khan, F., et al.

Australian Dental Journal

1998 43 (2): 117-127

Dental Splint Prescription Patterns: A Survey

Pierce, Calvin J. DMD, PhD, et al.

The Journal of the American Dental Association

1995 126 (2): 248-254

Aetna® Clinical Policy Bulletin: Temporomandibular Joint Syndrome (TMJ) and Temporomandibular Disorders (TMD)

Aetna Inc. web site

Last viewed: 9/23/2010

Editor’s notes: Clinical Policy Bulletin: Temporomandibular Joint Syndrome (TMJ) and Temporomandibular Disorders (TMD). Describes one major insurer’s position on the assessment and management of these disorders.

Bruxism/Teeth grinding web site

Last viewed: 9/23/2010

Occlusion in the New Millennium: The Controversy Continues, Part 1 (PDF, 429K)

Spear, Frank, DDS, MSD

Spear Perspective—The art and science of exceptional esthetic and restorative dentistry

3 (2)

Editor’s notes: Great Lakes Orthodontics web site.

Occlusion in the New Millennium: The Controversy Continues, Part 2 (PDF, 112K)

Spear, Frank, DDS, MSD

Spear Perspective—The art and science of exceptional esthetic and restorative dentistry

3 (2)

Editor’s notes: Great Lakes Orthodontics web site.

The Politics and Science of Neuromuscular Dentistry 1965–1999; One Man Versus the Establishment—1965–1987

Jankelsion, Robert

Myotronics Australasia web site

Last viewed: 9/23/2010

Editor’s notes: Manufacturer’s web site

The TMJ Association

The TMJ Association web site

Last viewed: 9/23/2010

Information you may wish to read before making a decision on treatment

Electromyographic activity of the temporal and masseter muscles at different occlusal positions

Petrovic, D. and Horvat-Banic S.

Medicinski Pregled (Novi Sad)

2007 60: 134-139

Occlusal splints for treating sleep bruxism (tooth grinding)

Macedo CR, et al.

Cochrane Database of Systematic Reviews

2007 4

Notes: Art. No.: CD005514

Editor’s notes: This review found insufficient evidence in the literature to conclude that occlusal guards reduce sleep bruxism; however, the study design was not intended to evaluate whether they reduce wear on the teeth, and was not suggesting that they are ineffective for that purpose.

Treatment of localized anterior tooth wear with a glass-fiber-reinforced composite resin: A clinical report

Akar, Gulcan Coskun, DDS, PhD and Dundar, Mine, DDS, PhD

The Journal of Prosthetic Dentistry

2007 97 (3): 133-136

Is there an association between occlusion and periodontal destruction?

Harrel, Stephen K. DDS, et al.

The Journal of the American Dental Association

2006 137 (10): 1380-1392

The clinical usefulness of surface electromyography in the diagnosis and treatment of temporomandibular disorders

Klasser, Gary D. DMD, and Okeson, Jeffrey P., DMD

The Journal of the American Dental Association

2006 137 (6): 763-771

Is occlusion becoming more confusing? A plea for simplicity

Christensen, Gordon J., DDS, MSD, PhD

The Journal of the American Dental Association

2004 135 (6): 767-770

Physiologic vertical dimension and centric relation

Shanahan, Thomas E. J.

The Journal of Prosthetic Dentistry

2004 91 (3): 206-209

Occlusion-Based Treatment Planning for Complex Dental Restorations: Part 1

Keough, Bernard, DMD, CAGS

The International Journal of Periodontics & Restorative Dentistry

2003 23 (3): 237-247

Occlusion-Based Treatment Planning for Complex Dental Restorations: Part 2

Keough, Bernard, DMD, CAGS

The International Journal of Periodontics & Restorative Dentistry

2003 23 (4): 325-335

Prosthetic rehabilitation of extremely worn dentitions: Case reports

Cura, Cenk, DDS, PhD, et al.

Quintessence International

2002 33 (3): 225-230

The Effect of Increasing Occlusal Vertical Dimension on Face Height

Gross, Martin D., BDS, LDS, RCS, MSca, et al.

International Journal of Prosthodontics

2002 15 (4): 353-357

A common-sense approach to splint therapy

Dylina, Tim J., DDS

The Journal of Prosthetic Dentistry

2001 86 (5): 539-545

Now is the time to observe and treat dental occlusion

Christensen, Gordon J., DDS, MSD, PhD

The Journal of the American Dental Association

2001 132 (1): 100-102

The speaking method in measuring vertical dimension

Silverman, Meyer M.

The Journal of Prosthetic Dentistry

2001 85 (5): 427-431

Widespread pain and the effectiveness of oral splints in myofascial face pain

Raphael, Karen G., PhD and Marbach, Joseph J., DDS

The Journal of the American Dental Association

2001 132 (3): 305-316

Clinical Indications for Altering Vertical Dimension of Occlusion

Harper, Richard P., DDS, PhD, FRCD(C) and Misch, Carle E., DDS, MDS

Quintessence International

2000 31 (4)

Notes: Quintessence Publishing

Tooth wear treated with direct composite restorations at an increased vertical dimension: Results at 30 months

Hemmings, Kenneth W., BDS, MSc, et al.

The Journal of Prosthetic Dentistry

2000 83 (3): 287-293

Treating Bruxism and Clenching

Christensen, Gordon J., DDS, MSD, PhD

The Journal of the American Dental Association

2000 131 (2): 233-235

Integrated Electromyography of the Masseter on Incremental Opening and Closing with Audio Biofeedback: A Study on Mandibular Posture

Gross, MD, et al.

International Journal of Prosthodontics

1999 12 (5): 419-425

Restoration of the Severely Worn Dentition Using a Systematized Approach for a Predictable Prognosis


The International Journal of Periodontics & Restorative Dentistry

1998 18 (1): 47-57

Abnormal occlusal conditions: a forgotten part of dentistry

Christensen, Gordon J., DDS, MSD, PhD

The Journal of the American Dental Association

1995 126 (12): 1667-1668

Pain Control During Nonsurgical Periodontal Therapy

Kumar, Purnima S., BDS, MDS, PhD and Leblebicioglu, Binnaz, DDS, MS, PhD

Compendium of Continuing Education in Dentistry

Treating Bruxism and Clenching (Letter #1)

The Journal of the American Dental Association

Editor’s notes: Editorial comment re: Dr. Christensen’s recommended treatments for bruxing- discusses mandibular rest and isokinetic stretching, used successfully for 40 years, by Dr. James H.Quinn, DDS.

Treating Bruxism and Clenching (Letter #2)

The Journal of the American Dental Association

Editor’s notes: Editorial comment re: Dr. Christensen’s recommended treatment for bruxing in young patients- discusses possible orthodontic complications from splint use in growing patients, by David J. Harnick, DDS, MSD (orthodontist).