Occlusal diseases

-Signs of occlusal disease are so easily observed even at the earliest stages when progression of the damage can be intercepted;our duty that find occlusal diseases at earily stages cuze become worser and treatment more difficult.

-Symptome of occlusal disease may not be as obvious;sometimes patients have proxymy and temporomandibulan disorder but no signs and symptoms on teeth and can't seen.

- If therapy is not delayed until the damage is severe the complexity and cost of treatment can be dramatically reduced;fractured cusp we put crown or wear on incisal edges we put composite but if three to quarters of tooth are lost, reduction in facial height and the mandible protruded cuze ICP is lost so we return ICP to RCP and restor whole tooth and that's coasty and take a lot of time to treatment .

Occlusal disease is

-The most common destructive dental disorder .

- Contributing factor to eventual loss of teeth; if the patient has TMJ disorder with excessive wear and we can't restor tooth so we will extracted it Or if he has fracture on the buccal or lingual wall of the tooth and this fracture is subgingival until if try lengthen the crown we can't restore tooth cuze this case is infra bony so we extract it .

- Reason for needing extensive restorative treatment .

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- Factor associated with discomfort of the masticatory system structures, including pain/discomfort in the muscles, the teeth, and area of the TMJs ; if the patient feels pain on one side of arch so he avoids chewing on this side then hypertoincity of muscle on this side later on muscle disorder.

- Factor in instability of orthodontic treatment .

- Reason for tooth soreness and hypersensitivity ;sometimes occlusal disease is chipping of the part of tooth or wear so will be exposed of dentine and that's painfull cuze dentine contains nerve endings.

- Most commonly mis-diagnosed leading to unnecessary endodontics ; if the patient's tooth is painful and no caries and severe pain each time he bites and some dentists don't know and think the patient has inflammation in the nerve of the tooth and do endodontic treatment and that's right but there will be unneseccary access cavity ann unneseccary cutting in the tooth and no pulp at the end tooth become non vital and failure rate increase .

- Most un-diagnosed dental disorder until severe damage becomes too obvious to ignore; because dentist doesn't do agood examination .

Lytle was the first to introduce the term occlusal disease and defined it as the process resulting in the noticeable

loss or destruction of the occluding surfaces of teeth.

Abrahamsen defined different causes for destruction of tooth structure. He showed how combined mechanisms of chemical effects could interact with occlusal overloads to intensify destruction of the tooth surface.

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Sometimes we can't defind occlusal disease by asingle factor it's amultiple factors

Basic mechanisms of tooth surface deformation

According to Grippo et al deformation of tooth structure results from 3 basic physical and chemical mechanisms that can act alone or in combination;

1- stress : results in compression flexure and tension, and this can produce microfracture and abfraction as a dental manifestation. - abfraction; wear on occlusal surface and cervical lesion" non carious lesion " - microfracutre; break in tooth sensitivity that may be noticeable and sometimes non noticeable.

2- friction: includes abraision from exogenous material and attrition which is endogenous and results from empty mouth bruxing and parafuntion(nail biting,lip biting), also occure due to ingestion excessive amount of vegitables and end point of which is wear of the tooth surface.

3-corroison: Due to ingestion a lot amount of citritis food ( high PH ) . OROccupation of the patient ; he works in a factory and there's chemicals and acids and that's affect on the teeth.

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These mechanisms often overlap and interact to accelerate structural damage . This is why deformation of teeth should be considered multi-factorial, though occlusal overload appears to be almost always the dominant factor that must be addressed in treatment planning. **Attrition:Defind as wear due to tooth friction and this occurs in patients who always tighten on their teeth espeically at sleep. This kind of wear results from bruxism and empty mouth parafunction When wear penetrates enamel into dentine wear increases seven times faster.

**Abrasion: Defined as wear due to friction between a tooth and an exogenous agent.this kind of wear come from chewing of food or tobacco chewing. It can also be a result of excessive tooth brushing or improper use of dental floss, tooth picks, pencils, or any foreign object.

**Erosion: It is tooth surface loss due to chemical or electrochemical action, which does not include bacterial activity;(when there's caries bacteria produce acids that demineralize of enamel and dentine then progression of bacterial invasion.

Endogenous erosion: can result from:

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1.Bulemea ; patient eats and vomits intentially due psycosis

2.Gastro-eosophegeal reflux (hydrochloric acid and proteolytic enzyme) ; problems in stomach (food go out stomach to mouth ) 3.Gingival crevicular fluid.

Exogenous erosion : can result from :1. types of food 2. Enviroment

**Abfraction:-The role of occlusal overload on non-carious on cervical lesions.first described by Lee and Eakle as possible consequence of tensile stresses through bending of teeth under occlusal overload . *** The mechanism : occlusal overloading – stress concentration in cervical area and in this area the enamel is thinner so there will be chipping in enamel and then dentine .

- Numerous investigators have claimed that that occlusal loading force do cause flexure of the teeth that produces microfractures and structural loss of the cervical area.

- Acids penetrate the microcracks and undermines tooth surfaces that are then more suceptible to mechanical deformation.

- Some suggest that those wedge shaped lesions with sharp edges are a result of tooth paste( vigorous tooth brushing )

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Examples of occlusal disease :

Attritional wear:

-This type of wear on the lower anterior teeth ( mainly central incisor) – localized wear -is one of the most common untreated problems. -localized wear due to crowns aren't polished on maxillary arch- ceramic crowns- harder than enamel so if they aren't polished cause wear.- it is also a typical sign of two prevalent causes of such wear -** The first place is to look at the posterior teeth (post interference and that's make the patient to avoid this interference by pushing mandible forward against upper ant.teeth so wear in lower ant.teeth).- Or in other words-- where deflective incline interferences to centric relation are so often the cause of a forward slide of the mandible during closure into maximum inter-cuspation. - This forces the lower anterior teeth forward into a collision with the upper anterior teeth. - The muscles try to erase the colliding tooth surfaces

through bruxing or para-functional rubbing.

**The second place is most common cause for this type of wear is direct interference of the anterior teeth to complete closure in centric relation; either do filling or

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crown is over contouring and high contact on them then wear on ant.teeth.This will always be the result of improper restorations on the anterior teeth or improper positioning of the anterior teeth.

-Interferences to the mandibular envelope of function is also a trigger of attrional wear.

-Correct diagnosis requires the complete understanding of occlusal principles.

Erosion of enamel - A combination of acid from fruit, abraision from mulling the fruit between end to end anterior contacts;(Abrasion in addition to Erosion )- Erosion's shape; dentine inside and shap enamel on edging .- attrition from bruxing resulting in an invagination of the incisal enamel. - Evidence of erosion is obvious because cupped out dentine areas can’t be contacted by opposing teeth.

Splayed teeth:

-The teeth will move toword labial change their angulation due to posterior bite collapse no centric stops on

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post.teeth so the mandible pushed forward easily changing the postion of ant.teeth . -The same type of mandibular deflection that causes wear problem can in a different patient force the upper anterior teeth forward; post.interfernce will cause splayed on ant.teeth so the mandible try to runaway from the interference posteiorly and move forward pushing against maxillary incisors that move to avoid pressure on ant.lower teeth . OR another patient has waer on ant.lower teeth .

- which determines what happened we don't know and weakest point that has destruction so if the teeth are the weakest point wear of the teeth will occur , periodontium is weakest movment of the teeth , muscle is weakest pain on muscle , TMJ is weakest pain in TMJ .

- Spaying of teeth is a common sign of occlusal disease that should be diagnosed and treated early by eliminating the deflective interferences that force the mandible forward.

- Other signs of the same problem are fremitus and soreness of the anterior teeth at early stages.

-Improperly contoured restorations that are too thick on the lingual of the upper anterior teeth or overcontoured lower restorations are common causes of splaying .

Destroyed dentition :

This is a result of not intercepting occlusal disease early.

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-Signs of severe wear, fractured anterior teeth and elongated alveolar processes.

-the wrost patient to treatment is dentinoalveolar compansation ; teeth will be smaller and to keep vertical dimension the maxilla and mandible will be lowered and compensate lost area of the teeth by bone ,it's a nightmare ( sometimes we need to extract the teeth or implant to change the relation )

- Treatment is comples and results are compromised.

Advanced occlusal disease :

This results from a combination of attritional wear and moved teeth.

Anterior Guidance Attrition :

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-This occurs when anterior teeth either interfere with centric relation closure or with functional jaw movement patterns (envelope of function)

-develop early signs of attritional wear of the lingual surface enamel of upper anterior teeth

-this type often goes undiagnosed until the incisal edge is too thin and transparent that starts chipping and fractures.

Sensitive teeth:

-One of the most missed diagnosis is failure to know that a common cause of hypersensitivity is occlusal overload.

-sometimes the patient feel pain on his teeth duo to biting or cold- hot drink.

-The sensitivity can result from pulpal hyperemia(inflammation in the pulp ) or the effect of non carious cervical cracks.

Sore teeth:

-Compression of periodontal ligament can be combined with pulpal hyperemia to cause considerable soreness or pain upon biting.

-if any empty mouth clenching causes discomfort in any teeth this indicate occlusal interference.

- if the patient is painful when bites on one of his teeth and the dentist examines him and no caries ,the most probable cause is occlusal interferences that cause pulpal hyperemia and pain on

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-How diagnose it ??? -By using clench test ;hard,chewy material ,put it on the tooth

and ask the patient to bite then examine at which tooth is painful to patient when bites and if we find this tooth we examine it if has crack,fracture areas and why cause soreness.

Hypermobility:

-some of teeth that undergo occlusal truma that cause hyper whiting of membrane surrounding the root and bone loss occured is revesible ,cuze if we remove occlusal truma it will heal in contrast to periodontal disease the bone loss is permanent(irreversible ).

Splet teeth and fractured cusp;

Occlusal overloading is severe until part of the tooth is broken or from the center is broken and without any caries,sometimes the patient comes with lingual cusp of upper teeth and buccal cusp of lower are affecte on the restoration cuze tooth is intact and no any type of filling will bind with tooth

-so sometimes we put pins but it isn't effective so we do elective root canal treatment , why is elective ??? because tooth don't need root canal treatment and we require it inorder to put sth inside the canal to return permanent retoration.

Painful muscles: -a sign of occlusal disease is painful muscle cuse muscle are the

weakest strucrues in the joint.-muscle spasm ,muscle splinting , myositis

**So it's important to understand diagnosis and treatment of all forms of occlusal disharmony and dependent on clenching's knowledge of the total masticatory,design and function.

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