1 Occlusal Splints

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The table below shows some basic occlussal terms; please take a look at them before proceeding with this lecture, most of the concepts depends on it.

When we’re relaxed (mouth is open ) the mandible will  be in its Muco-Skeletal Muco-Skeletal Position Position of the Joint ( MS ) within the glenoid fossa . This position is defined as : “ The most orthopedically stable joint position , it happens when the condyles are in their most superior-anterior   position with with the disk in between between and the head head of the condyle is touching distal slope   of  of the articular emeicne “ or the CR/RCP position . The MS positon of the mandible is considered the most stable position, because on the slope of the glenoid fossae the bone is very thick (1) and it consists of a

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cortical bone (2) which makes it the ideal stable and load-bearing area. ( see figure 1)

So when we’re relaxed (not chewing or doing any function with the mouth) the mandible relaxes, but the muscles will pull the mandible in order to reach the MS  position of the mandible mandible .

 Now what happens happens when we close our mouth (as when we’re eating), the mouth will close and the occlusion for a brief time would be cusp to cusp, now cusp to cusp is not an occlussally stable position but rather considered as an occlussal interference, so here the body is not looking for the Muco-Skeletal position position anymore, but rather it is looking for the most stable occlussal position to solve the  problem of the interference that occurred upon closure of the the mouth . In order for the body to solve this interference and achieve maximum intercusption (MCP/ICP ) ( occlussal occlussal stable position position during function function ) and change the position position to cusp to groove which is occlusally far more stable than cusp to cusp. The muscles will contract ( especially the lateral pyerydoid muscle ) with this action of the muscles the mandible will move a little forward and thus achieving cusp to groove or the MCP/ICP MCP/ICP .

 Now what happens happens when we’re eating eating (functioning) (functioning) , while we chew we don’t eat in the CR but rather we function around the ICP ; meaning that at the end of the mastictory cycle a brief contact between cusps would happen ( this brief contact is essential to incise food ) meaning that we don’t function exactly at the ICP because we don’t eat food by opening and and closure but rather by doing lateral movements , so we’re functioning AROUND ICP .

 Now the above senieros senieros hold true true for 90% of the population, population, meaning that 90% 90% of us will have occlussal interference upon closure and their mandible will move forward a little bit to accommodate and solve those interference by going cusp to grove ( ICP /MCP ) , the other 10% have different screnrieros ; they’re always on

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their MS position because they don’t have occlussal interferences and thus the  body didn’t feel feel the need to need to change positions and move the mandible a little forward; meaning that their ICP is the same as their CR .

 Now a question rises rises , the joint position in 90% of us while closing closing and chewing chewing is not in its orthopedically stable position position ( the MS ) , why didn’t didn’t we develop any  problems in the the TMJs ? here, here, the condyles new position that the body made made which is a little bit forward is still compatible with the health , unless there are unusual movements or loading that’s happening in the joint ( e.g. burixisim , clenching )

Protected d Occlu Occlu sion  There’s a concept called M utu all y Protecte , in simple words this concept means that: “anterior teeth protect the posterior during protrusion and  posterior teeth protect the anterior anterior teeth during during mouth closure closure in maximum maximum intercusption .” .”

The anteriors will prevent the premature contact of the postieror teeth during  protrusioin and and thus protecting protecting them , and the posteriors posteriors are more more vertically placed and have more roots thus the force applied to them would be more than the anterior and thus they’ll protect the anteriors ; they’ll withstand more force than the anteriors. Any interference that disturbs this mutually protected occlusion will lead to tliting and occlusion interference during function and protrusive movements, that’s that’s why most restorations and prosthesis (crowns (crowns and bridges ) are made to conform to  patient’s existing existing ICP , meaning meaning that we must have the maximum number of contacts ( every tooth wither it’s sound or restored must have an opposing contact on the other arch ) in order o rder to preserve this mutually protected occlusion. Consider the following examples:

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A dentist might be presented with single high crown prosthesis; he’ll suggest that trimming this high crown will resolve the case. But what will actually happen is that supra-eruption of the opposing teeth in the other arch will occur. (So the mutually protected occlusion concept is damaged, here when the patient would protruded he’ll have occlussal interference at the back) the back) this might lead to either breakage of the crown or in the most severe cases TMJ  problems. - A dentist who had just finished doing a restoration, he didn’t check to see if it’s high in occlusion (high spot) or not. Now whenever the patient is chewing on that side the muscle will contract to  prevent him from hitting that spot every time, at the long run the muscles will  be tired and TMJ TMJ  problems will will occur (again the mutually protected occlusion is damaged).

In the above two examples you now realize how important is to maintain this mutually protected  balance, and now you you realize why we we love to have maximum number of contacts on each and every tooth , that’s why most restorations and prosthesis (crowns and bridges ) are made to conform to  patient’s existing existing ICP . for for this to be an appropriate appropriate form of treatment ICP must be stable and occlussal anatomy of all restorations must be carefully shaped to reproduce correct contacts; meaning that we must have the maximum number of contacts (every restorations or prosthesis must not damage the mutually protected occlusion , or in other words , a restoration or a prosthesis in the back must not interfere upon protrusion and a

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prosthesis or restoration in the front must not also interfere upon closure ) . (see figure 2 : A: a contact in the back prevented lead to less stable postion in the articular and thus TMJ problems , B : good crowns/restorations crowns/restorations show no interference and thus good position in the articular was achieved and no problems were found )

The question that rises now is how do we manage those patients who have interferences? interferences? Or how do we restore the mutually protected occlusion? The answer is we give them occlussal splint, consider figure 3 and 4 , in 3 notice how a faulty crown is damaging the mutually protracted occlusion and that the lateral pyerydoid muscle is always contracting contracting and notice in 4 how we added an occlussal occlussal splint or an antieror guidance that relaxed the hyperactive muscle.  After we’ve covered covered the basic concepts of occlusion physiology physiology and mutually mutually  protected occlusion, occlusion, and aft er er we’ve understood the need behind occlussal splints we’ll talk about them for the rest of this lecture.

The definition of the occlussal splints is: “Any removable artificial occlussal surface used for diagnosis   or  or therapy   affecting the relationship of the mandible to  affecting occlu ssal stabil i zation , for tr eatment atment of the maxillae. It may be used for occlu temporomandibul temporomandibul ar disorde disorderr s  ven t wear  wear of the dentition “ GPT-8  , or to pr even GPT-8 Okoson defined it as follows: “ it is a removable device usually made of hard acrylic , that fits over the occlussal and incisal surfaces of the teeth in one arch , creating precise occlussal contact with the teeth of the opposing arch . So, the occlussal splints devices can be used to either stabilize the occlusion, treat TMJ problems or aid in diagnosis. But how exactly can we achieve a diagnosis diagnosis with occlussal splints? splints? Consider the following example, you made a new bridge work for your patient and inserted into his mouth, couple of weeks later the patient is complaining of a pain in his jaws, you’re suspecting that a high spot in your bridge is that cause of this but still you

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need to confirm that. What you’re going to do is that you’re going to make him an occlussal splint (a night guard) and ask him to use it, the patient reported back that he’s now happy and no pain is found, so you concluded that the high spot on that  bridge work was the cause, so here the occlussal splint was used used as a diagnostic diagnostic tool. Occlussal splints can have many different names like (refer to the slides to have the full list ) :         

anteiror reprogramming splint anterior postioning splint annterio repostioing splint flat occlusal splint  bite splint mandibular advancement device muscle deprogramming splint occlusal protecting splint Lucia Gig

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Orthopedic deprogramming device

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Occlussal correcting splint

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Distal push splint

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Buccal separator

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discluding splint

It’s indicated in the following cases : 

Temporomandibular Temporomandibular disorders ( first line of treatment )

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Myofascial pain

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Disc displacement disorders

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Arthritides of the TMJ

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Headache/migrane

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Sleep burxism

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Sleep apnea

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Parckinson’s Parckinson’s disease

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Oral tardive dyskinesia

Its applications are as follow: 

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Occlussal rehabilitation : o Ortothodontics o Periodontics o Prosthodontics  Establishemnt of CR (where we can’t determine CR )  Protection of new restorations ( like in the case of vnerees and all ceramic restorations )  Creating space for restorations restorations o Phantom bite ( where the patient can’t determine a bite ) . o Others :  Diurnal burixism  Sports  Cheek/ fingernail biting  Electroconvulsive Electroconvulsive therapy  Lip commissure burn  Esophageal reflux  Sinusitis  Diagnosis of possible cause of TMD

Splints are indicated to reduce harmful effects : o Teeth : attrition , fractures and mobility or pain o TMJ : pain , traumatic arthritis , degenerative remodeling o Muscles : pain or spasm

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 Note that splints splints can not cure bruxism bruxism because because it is a centrally centrally mediated disorder disorder . Howevere it can reduce its effects through : 

Providing a softer surface to wear ( it’s hard acrylic and it won’t wear teeth )

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Redistribute Redistribute the tramtic forces over larger number of teeth t eeth

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Splinting teeth together and provide ideal occlussal contacts.

Occlusal Splints can Splints can be classified according to :

1- Material of construction: 

Hard

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Soft

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Bilaminar

2- Coverage: 

They could be full coverage or partial coverage

3- Function : 

Stabilization

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Repositioning

4- Position : 

They could be maxillary

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or mandibular

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acryli li c  1- H ard acry  is the most common used  is material, which is:

1- chemically cured or heat/pressure heat/pressure  processed 2- hard on both occlusal and fitting surface 3- Durable 4- Easy to repair 5- More retentive 6- Less prone to change in color & plaque accumulation.

Other properties mentioned in the slides:

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Vacumformed vinyl splint

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Soft on both surfaces

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 Not durable

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Cannot maintain stable occlusion

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Helpful in emergencies but might lead to increased muscle activity

2- Soft or resilient plastic night guard : Giving a patient with tempomandibular disfunction (TMD) a soft night guard is  just like giving giving him/her a chewing chewing gum and ask him to chew it!! Thus; Thus; instead of making the muscles relaxed you're making the condition worse ! So ,what is the use of soft night guard ?! They're just used in emergency cases, if someone has acute pain and you want something to open his bite to relax the muscles , you should give him soft night guard for few days then make him a full hard night guard ….. JUST in Emergency cases 3- Bilaminar ( dual laminated) : - The side toward the teeth is soft soft ,and the one toward the occlusal side side is hard . - Can maintain a stable occlusion

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Partial coverage coverage :1- Anterior bite plane 2- Posterior bite plane. Anything you wear for more then 4-6 weeks with  partial coverage will will lead to irreversible irreversible changes in the occlusion, that's occlusion, that's why full coverage is  preferable. If a patient uses a posterior bite plane and wear it continuously for 4-6 weeks ,there will be supra eruption for anterior teeth ,and ends up with posterior openbite. And the same with anterior bite plane where you will end up with anterior openbite within 4-6 weeks. These are types of irreversible damage, that’s why that’s why we hate partial coverage splint !!

Other examples of partial coverage splints include 1- Lucia Gig 2-  Nociceptive Trigeminal Trigeminal Inhibition Inhibition Tensin Supression System (NTI). 3- The Anterior Medline Point Stop (AMPS) devices.  If

you used them you have to strictly tell the patients not to wear them continuously, otherwise we’ we’ll have supra-eruption and end up with an openbite .

Lucia Gig

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1- Stabelization (permissive) ,the one we will fabricate in the clinic which is called (Michigan or stabilization appliance) (figure 6 : A) It has flat occlussal surface with the opposing teeth ,doesn't have indentation ,it's called stabilization because it puts the mandible in a muscoskeletal stable (MS) (MS) position ,it ,it puts the condyle in its anterior superior position. Repositioning device,, it has indentations, I 2-Repositioning will take the bite in anterior position , in order to unload the disk, the idea is unload the disk if I have the loading loading on the retrodiscal retrodiscal tissue tissue and the  patient has extensive extensive pain I’ll ask the patient to  protrude and take take a bite and make make an anterior  bite plane for him him which will relieve relieve that pain (figure 6 : B) B) 

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Can be used as first line emergency treatment only to reduce acute pain , so it’ it’s only used in short periods of time Can lead to irreversible change in occlusion which will cause a disaster after a while.

3-Pivoting concept : they thought that putting a  partial coverage posteriorly by using a bite plane ( the pivot ) , that it will bring the condyle downward upon clenching on the pivot thus reliving the traumatic load and allowing the disc to resume the normal position . But it has proven that this concept is not true.(figure 7)

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Could be maxillary or mandibular. 1- Maxillary appliances : 

have more coverage  less likely to break

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more stable

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 better retention retention

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More versatile

2- Mandibluar appliance : 

are used for class class III occlusion occlusion &posterior crossbite

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they have minimal show on the patient

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easier to speak with

The splint therapy is effective in reducing the pain in 70-90 % of the TMD  patients, although they do work their true mechanism mechanism of action is still not known, known, there are some proposed “theories” theories” concerning their mechanism of action: The table below summarizes these theories : Dental reasons for efficacy

Nondental reasons for efficacy

Alteration of the occlusal condition

Cognitive awareness

Alteration of the condylar position

Placebo effect

Increase in the vertical dimension of occlusion

Increased peripheral input to the central nervous system decreases motor activity Regression to the mean(natural fluctuation of symptoms)

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(nondental), when you give The most convincing one is cognitive awareness (nondental), a patient a night guard you remind him not to chew , to reduce bruxism . - Placebo effect ,whenever you put anything between his teeth he feels that you care for him this why he will feel better , there’ there ’s a dentist who did a research on three different groups . The first one had a real night guard that the sample wore for 2 hrs , the second sample had a fake one where the night guard only covered the palatal surface and the last sample didn’ didn’t recive and night guards  but instead they were treat with a compasinte compasinte and a caring way way via the dentist . Surprisingly all the three groups showed decreased TMD symptoms. - Increased peripheral input to the central nervous system so decrease motor activity - regression to the mean (natural fluctuation of symptoms) : Which means that if a person has a stressful life event in a specific period of time he will suffer from TMJ problems ,but when this stress goes away his condition will be resolved and the TMJ will come back to the natural relaxed state.

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Stable with no rocking Ease of placement Smooth with no sharp edges Reasonable esthetics The contact should be - Balanced in the centric relation; every single tooth has to have centric stop. when you put the night guard in the patient mouth let him bite and put a horseshoe articulating paper , every single tooth in the lower should have a mark on its occlusal surface, if there are marks on the posterior teeth but nothing on the anterior; supra eruption of the anterior will result .If there is anterior contact without

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 posterior contact supraeruption supraeruption of the posterior posterior will happen. happen. If all teeth have a contact except one tooth ,this tooth will supraerupt alone and you will notice in those patients with night guard when they wake up in the morning they will said that they bite on one tooth ,why ? due to t o supra eruption. -

Occlusal surface should be flat Immediate posterior disclusion on protrusion and lateral excrusion 0.5 mm freedom in centric

1- Take a full upper upper and lower alginate alginate impression all teeth should should be recorded. 2- Bite registration on RCP preferably with facebow record ,take precentric occlusal registration. registration. Upper and lower teeth should not touch when I take the bite ,, there should be 2 mm mm separation posteriorly posteriorly and about 3-4 mm separation separation  between the incisors incisors anteriorly. 3- Mounting the casts using facebow record and the bite provided. 4- After the mounting do block out (very important ) If you do block out before mounting you can't mount the cast because the cast will not stick to the bite . Mount first then block out Where you should put the plaster ?

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in pits and fissures, the embrasure area in the lingual side and cover the lingual gingival margins. do not block out labial undercuts because you will use the labial undercuts for the retention of your appliance .

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Draw a line to determine the extent of the splint ,4-6 mm of the palatal gingival margins ,2-3 mm from the labial surface of teeth. 5- Then do wax up using two layers of wax ,adapt them on the surface ,this will  produce indentations indentations which you have to remove remove them later ,you just just need a flat surface. 6- Use an articulating paper to produce dots on all the occlussal surfaces there must be marks marks ( contacts ) the dots showed be : a. All teeth must show  contacts in ICP  b. Only the canines  contacts in lateral extrusions c. Anterior guidance component  showed be only on the canines (  preferable ) or canines and lower incisors 7- Add wax labial and mesial to lower canines to establish a Canine ramp or  just on one canine canine ,every doctor has has his own way way and both are correct correct 8- Then do flasking 9- Packing in heat cured acrylic

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Inspect the appliance for sharp margins

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Check for sever undercuts.

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Carefully place the appliance in the mouth and don't force it into place and don't allow the patient to insert it at this stage.

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The splint should have a light comfortable pressure pressure with a soft click.

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Make sure that it's fully seated before you start adjusting the occlusion.

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If the appliance is not stable or rocking or not retentive - check for undercuts - consider relining - consider remaking Use an articulating paper to check for occlusion ,first establish even contact on all teeth at RCP,then check for canine guidance on lateral excursions and  protrusion, if you do the opposite opposite it won't work work . Always check RCP first.

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give post operative instructions , the splint should be worn as recommended recommended  by the dentist. saliva flow will increase in the first two weeks ,which is normal of artificial appliance.

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It's normal to feel tightness for the first 2 minutes of wearing.

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If it's not worn keep it in water (very important)

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Regular check up is mandatory

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Do Not wear the splint for more more than 4-6 months without review review

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Brush the appliance with soap after meals Don’t bite or clench continuously on the appliance ,it's there to make you relax

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Review after 7 days to recheck the occlusal contacts. Remember that if the patient is suffering from TMD it will be difficult to establish centric relation record correctly from the first appointment so you have to repeat it again .the patients will have pain on the first appointment appointment and their muscles are contracted so the RCP won't be correct at the  beginning ,so what what to do ? First fabricate the splint on RCP, then after one week if the muscles improved the mandible will get backward a little bit, then test it another time, till the signs and symptoms symptoms of muscular tenderness goes away .

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If I want to use the position of the mandible for restorative purposes purposes ,the occlusion shouldn’t be changed for at least two consecutive appointments appointments  before I can go ahead.

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