Night Guard Types – Different classes of Night Guards
Night guard or occlusal appliance classifications. Some are to treat or manage TMD some are simply to protect teeth wear.
1. Anterior midline stop device or anterior midline point stop (AMPS)
This appliance is a small one that only contacts in the anterior. Care needs to be taken that in protrusive and excursives the posteriors never can hit and the patient can not lock in front of or off the appliance. There are many common names and many clinicians will slightly modify this and name one after themselves. The most common is the NTI; other types are Hawley bite plane=Kois, Sved appliance, Best Bite Discluder, and the numerous spinoffs named after different clinicians.
The slight differences with these are how many teeth they cover, how many anterior teeth are in occlusion, and whether incisal edges are covered or not. I prefer the NTI except on deep bite/class II, then I go B-splint. AMPS can be constructed on the maxillary or mandibular teeth. Depending on style, can be great to use in conjunction with occlusal equilibration as one reduces the bite plane until IPC and then continues adjusting both bite plan and teeth until all MI=CR.
2. Full coverage night guard in CR with anterior guidance
Maxilla or mandible. Fabricated to coincide at patient’s CR. An anterior ramp and some adjusting ensure there are no posterior occlusal contacts in protrusive and lateral movements. Typically only the canines touch in left and right lateral movements, and the incisors in protrusive movements. Should be stable enough to not move during CR closure or any eccentric movement. Most wold consider a Michigan appliance a maxillary version of this and Tanner as a mandibular example of this. MAGO is another common name and stands for Maxillary Anterior Guided Orthotic. There is some variance on whether the appliance can have protrusive on just the canines, just the anteriors, or share the movement.
3. Full coverage night guard in CR with a flat plane
Same as above but lacks anterior guidance. Appliance is flat and usually has some posterior contacts during excursive movements (think group function).
4. Full coverage night guard not in CR with anterior guidance
Same as #2 but fabricated in MI (maximum intercuspation) usually. If patient is a bruxer they will likely turn this into #2 IMHO. I also believe the difficulty with obtaining and maintaining true CR results in most appliances being in this category that are attempting to be #2.
5. Full coverage night guard not in CR with a flat plane
Same as #3. This is probably what a store bought one will likely be. A bruxer will possibly be worse off in this.
6. Posterior only appliances
Posterior occlusal contacts only. Out of favor by almost everyone. “Gelb” appliance or a Posterior Pivot are common names.
7. Mandibular anterior repositioning appliances
Put the mandible in a specific anterior position. Some allow some amount of movement in a protrusive or lateral direction from the directed position. Often cover both the maxillary and mandibular arches. Almost exclusively used for snoring or sleep apnea.
8. Soft appliances
Typically full coverage on either the maxillary or mandibular arch. Their occlusion varies as they are compressible and therefore the occlusal contacts change with bite force. Not for long term use and not for grinders or clenchers but rather acute pain. Most common use we see is temporarily to relieve pain or for protection, like an athletic mouth-guard or Aqualizer. Aqualizer review from a patient that I think is pretty accurate. Classic Okeson study on soft splints vs hard splints is that they increase the muscle activity which is usually the opposite of what we want. Okeson JADA 1987
“Dr Bryan Bauer gave me an Aqualizer Ultra temporary oral split, medium volume, and asked me for my opinion. I used it for 3-4 non-consecutive nights. My jaw hurt a little the next day, probably because my bite is deep and this split is very thin. However, it was very easy to position, with clear instructions. (Don’t try to talk with it in, as it might move!) The water-filled part provides nice cushion. This split would be great for grinders because it’s very cushiony. As a clencher, I have no problems with it, but I wonder how durable it would be after lots of pressure on the seals. I will definitely keep it as a backup in case my hard splint has problems.”
Another cheap version a friend shared with me is the Plackers night guard. It costs only about $1.
Some tips on the using soft appliances for diagnosis
Posterior occlusal contacts significantly reduce joint loading. This means posterior-only appliances work as well as full coverage appliances in this particular aspect.
- If the joint hurts when the condyles are going into a seated position, the appliance will need to provide posterior occlusion and be adjusted to provide an intercuspal occlusion with the mandible in an anterior or protruded position.
- If the joint hurts with the mandible moving, the appliance will need to provide posterior occlusion when the mandible moves to the painful location. This often means removing any anterior guidance from the appliance if the pain is in the joint on the same side the mandible is moving towards. If the joint on the side the mandible is moving away from experiences pain, it may be necessary to create non-working contacts in the occlusion of the appliance to support the joint.
Contacts on anterior teeth will load the joint. If this decreases the pain, our diagnosis begins to lean towards an origin of muscle. However, if this increases the pain then we lean towards the joint. If contacts are on just the posterior teeth – like a posterior pivot or aqualizer – and the pain decreases, our diagnosis begins to lean towards that of joint origin.
Designs and purpose Occlusal Device (OD) 1
Night guard fabrication checklist questions to use prior deciding on a design.
- Perio issues?
- Class II Div 1?
Anterior guidance Class 1 night guard
Class 1 night guards use lateral excursion on canines only and protrusive on centrals only.
Anterior guidance Class 2 night guard
Class 1 night guards use lateral excursion on canine first then centrals or the class 2 night guard uses protrusive on canine first then centrals.
- Use a class 2 when periodontally involved tooth (teeth) to decrease load on those teeth.
- If a patient has sore tooth from bruxism use class 2.
- Also use class 2 if patient is Class II Div 1, but this is a mandibular occlusal device.
Class 3 night guard is also known as a Michigan splint.
A class 3 night guard has all excursions on canines. However, I have seen prominent individuals showing Michigan splints with anterior guidance as well.
- Use class 3 if patient has an AOB and leave space for the teeth to erupt.
- Great appliance for patients with perio involving the anterior teeth.
Class 4 night guard is just wrong.
A class 4 has missing posterior contacts and/or posterior excursives.