Farah AL-hares Cons sheet #15 16/2/2015

Today we will today about non-carious lesions .

Non-carious lesion : loss of tooth structure (enamel and dentine )due to causes other than caries or trauma loss , it occurs between 31-56% of the population ,, most common teeth that are vulnerable to these lesions are : posterior teeth most commonly premolars ,, the age group is the Old-aged group due to more exposure to whatever was causing the non-carious lesion (there is a long time for exposure) and also elderly have more rescission and more root exposure (the root is more susceptible for these lesions than enamel).

So, what are the non-carious lesion ?

1. Abrasion2. Attrition3. Erosion4. Abreaction5. Non-hereditary enamel hypoplasia6. Hereditary enamel hypoplasia

Erosion :

Loss of tooth structure by chemical process not involving bacterial action.

Etiology :acid exposure.

A. extrinsic : from fluid that you drink like Pepsi , cola , citric juice ,etc.. its found on the labial surface of the upper teeth unless the patient is drinking with a straw it would be on the palatal surface . so a proper history taking is important.

B. Intrinsic : when the palatal surfaces of teeth esp. upper teeth is eroded 1.anoroxia nervosa2.bulimia nervosa3.GIT problems like vomitiyg4.pregnency

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Farah AL-hares Cons sheet #15 16/2/2015

Clinical appearance :-Smooth surface because it’s an acid so there is no sharp edges or sharp v-shape notch.-smooth surface ,rounded ,cupped-out defects , sometimes it starts as increased incisal translucency , sometimes you find amalgam restorations that is raised up with eroded tooth structure around, sometimes we can see pulp exposure in primary teeth.

Abrasion :Loss of tooth structure due to mechanical means of frictional causes (foreign body to tooth contact).Etiology:Incorrect brushing / forceful brushing when using a very hard tooth-brush or very abrasive tooth-paste,, happens most commonly on the left side if the person is right handed and visa versa .>>it’s not found on a single tooth but on multiple teeth (unlike abfraction that can be found on a single tooth).Abnormal habit : eating nuts البزرRemovable appliances : clasp on the tooth do an abrasion lesion (foreign body to a tooth).

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Farah AL-hares Cons sheet #15 16/2/2015

Clinical appearance :A v-shaped notches with sharp line angles , usually affects more than one tooth, the lesions are more wide than deep. Usually occurs at cervical margins because enamel thickness there is minimal ,, premolars and canines are commonly affected .

Attrition :Is a mechanical wear due to tooth to tooth contact at incisal or occlusal surfaces can also be found on proximal surfaces (because we have physiological teeth movement) so it can transfer the small contact area into a large contact area , most commonly in patients with parafunctional habits like bruxism and clinching and old-age people so putting a matrix band between teeth in an elderly person is much more difficult that in a young person because with time the small contact area becomes a large contact area due to the wear that happened inter-proximally.

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Farah AL-hares Cons sheet #15 16/2/2015

Clinical appearance:Matching surfaces : like the occlusal surface of the upper tooth with its opposite tooth in lower arch , both have wear facets , they are formed because once the dentine is exposed it wears easier than enamel .. smooth saucer-shaped facets on cusp tips and can be associated with flat occlusal surfaces , sometimes we can see fractures of cusps or restorations .

Abrfaction :Loss of tooth structure at cervical area caused by tensile and compressive forces during tooth flexure.

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Farah AL-hares Cons sheet #15 16/2/2015

Etiology :

Heavy eccentric occlusal forces resulting in micro-fractures and consequently break-down of cervical enamel then dentine .

Abfraction hypothesis : grippo suggested a hypothesis for abfraction , it stated that : as teeth flex under occlusal loads stresses are transmitted to the cervical area causing cervical enamel rods to dislodge , they are first destructed by allowing water and other small molecules to be transmitted between the rods and prevent their re-bonding , with time a v-shaped notch will develop.

Q: what are the differences between abrasion and abfraction ?

1. In abfraction > lesions are deeper more than wider , however in abrasion they are wider more than deeper.

2. Abfraction is found on a single tooth that has eccentric forces on it , but in abrasion it’s usually on more than one tooth.

3. If a patient come with poor oral hygiene and has a v-shaped notch it’s most probably abfraction not abrasion (cuz there is no forceful brushing) !

**affects buccal cervical area and can affect the lingual also , commonly associated with wear facets , deep narrow v-shaped notch commonly affects single tooth with interferences , dependant on magnitude ,duration ,frequency and location.

**Labial and lingual surfaces of maxillary central incisors are most affected then premolars and then canines ! why ?

Because the incisors are the first to erupt and because forces on the incisors are not with the long access of the tooth so it has heavy lateral forces on it that cause them to flex , the canines are the least affected because are very robust with long roots and good thickness of enamel .

Another cause for abfraction : tongue thrusting , the force from the tongue can cause abfraction lesions sometimes on the lingual surfaces .

If we have a tooth that has heavy eccentric or lateral forces on it it may lead to abfraction.

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Farah AL-hares Cons sheet #15 16/2/2015

Enamel hypoplasia :

Non-hereditary enamel hypoplasia : injury to the ameloblast that form enamel by trauma or infection resulting in turner tooth (enamel hypoplasia). It Looks like a single white spot (opacity) on the tooth and the enamel surface is intact , it can be white or brown spot , pitted or grooved depending on the severity of hypoplasia . >> florosis , high fever , amelogenesis imperfecta causes enamel hypoplasia but AI is a hereditary enamel hypoplasia.

Rx : morphology of the pulp is normal , radiographs can help you differentiate between Amelogenesis imperfect and dentinogenesis imperfect >

If a patient came with no enamel on his teeth it would be DI because of the improper adhesion between enamel and dentine that leads to premature loss of enamel (which was normal) /DEJ is disrupted , but if there were traces of enamel on the teeth or the enamel is pitted or grooved it would be AI.

DI :hereditary condition in which only the dentine is defective due to defective ododontoplastic activity , the enamel is weakly attached and lost early , the pulp chamber becomes obliterated(no pulp chamber) , the color of the teeth bocomes abnormal (brownish) and the roots are short .

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Farah AL-hares Cons sheet #15 16/2/2015

What are the predisposing factors for non-carious lesions ??

1. Dental anomalies: AI , DI 2. Malocclusion: certain malocclusions particularly involving anterior teeth might

bring the teeth into abnormal functional contacts such as edge to edge or other relationships or very deep bites or cause eccentric tooth contacts. >> causes abfraction and attrition .

3. Posterior tooth loss : when we have posterior tooth loss this will increase the load on anterior teeth so this will cause wear and abfraction lesion etc ..

4. Parafunctional habits : bruxism , pipe somking cause abrasion lesions.5. Restorative materials :like when we have porcelain verses natural tooth it will

wear it .6. Diet : like acidic drinks and citric acid .7. Systemic diseases : anorexia nervosa , bulimia nervosa and GIT diseases.

**Non carious lesion are related to modern life habit , diet and most importantly our stressful life .Tertiary dentine, obliterated tubules and sclerotic dentine are formed in non-carious lesions because it’s a long process so many patients don’t have sensitivity although the occlusion of the tooth is lost ! the lesion that might develop sensitivity is Erosion because it’s a rapid process which acidic dissolution and demineralization of tooth happen.

-TreatmentBefore any treatment, a proper diagnosis and recognition of the causes of the cervical lesions is important and will influence your long term success of the restoration ,like when a tooth has eccentric or lateral interference you should eliminate this interference before putting the restoration because if you don’t , the restoration will fall.

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Farah AL-hares Cons sheet #15 16/2/2015

To restore or not to restore ??!! ~We restore when :1. Aesthetic concern.2. If severe and we are afraid on tooth structure (structural durability).3. If there are signs and symptoms like pain and sensitivity(dentine

hypersensitivity).4. Cervical lesions resulting from carious incident should be restored.5. If we have secondary caries.6. Loss of occlusal stability (functional problem).

Many cervical lesions if they are small cavities with no signs and symptoms ,do not need restorations and require only preventive measures.

**We said we restore if we have dentine hypersensitivity but sometimes we don’t have to put a restoration and we can use other methods to treat hypersensitivity like desensitizing agents , fluoride application ,etc...

--Stages of treatment :

We have pre-restorative management and active treatment (which is any direct or indirect restoration).

Pre-restorative management like when we have occlusal interferences we do occlusal adjustments as in abfraction lesions. ( we try to remove the cause of the non-carious lesion) , otherwise the restoration will dislodge or will fall. Also elimination of habits (occlusal splints for bruxism) , and teach the patient about brushing techniques , and tell the patient to reduce consumption of citric juices , partial dentures for replacing missing teeth , orthodontic correction and surgical interventions sometimes (like doing surgical crown lengthening for sub-gingival lesions ).

Active treatment : we either put direct restoration or indirect restoration , but when do we put a direct or an indirect restoration ? according to the amount of remaining tooth structure for example a young patient came complaining from severe attrition on a posterior tooth then we would go for an indirect restoration like onlay ( gold onlay for exp.)

>>So when we have a localized area of hypominrelization or small cervical lesions and isolated lesions we go for a direct restoration (amalgam , composite , RMGI , compomer ) .

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Farah AL-hares Cons sheet #15 16/2/2015

>> Indirect restoration like veneer , onlay , crown when we have a large area or a very big aesthetic problem or when we have areas with high occlusal forces on them.

SO choosing the type of restoration will depend on severity of the case , the age of the patient (for young patients we go for veneers ,crowns and full mouth rehab. , for older patients we go for removable appliances etc..) and location inside the pateint’s mouth ( when the tooth is affected cervicaly ,a direct restoration would be enough ) .

Requirements of an adequate restorative material :

When we talk about non-carious cervical lesion we should have a restoration that has the ability to FLEX (low modulus of elasticity) with the tooth esp if the lesion is abfraction .>> like microfilled composite , GI .

We can use GI on root surface because of the fluoride release , biocompatible , easy to use but the disadvantags are aesthetic (it’s very white) , we can’t put it in high-stress areas , limited shades and high dissolution rate , high progressive water uptake leades to staining and decrease the hardness and wear resistance of the material.

>>We have to know the differences between RMGI and compomers .

RMGI & GI >> RMGI has better physical properties . conventional GI has high rate of dissolution and water uptake. Studies showed that both GI & RMGI release fluoride.

Composite is a highly technique sensitive . why don’t we have a good proximal contact with composite in comparison with amalgam ? because of shrinkage and we can’t do condensation to composite, so we use sectional matrix (it will do extra wedging effect and it’s very thin) for a posterior class 2 composite, also we do incremental build up to minimize shrinkage.

** problems of non-carious class 5 cervical lesions are marginal deterioration and loss of retention , so failure of composite in class 5 is because of the minimal thickness of enamel there , sclerotic dentine and the isolation cervically is very difficult .

In severe cases of attrition caused by heavy bruxism the occlusal contacts between upper and lower indirect restorations should always be casted in metal to be able to withstand the heavy abrasive load of occlusion in those patients , so If a patient with parafunctional habit came to you , you have to put the posterior occlusal surfaces in metal if you can .

GooD LucK \^o^/

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Farah AL-hares Cons sheet #15 16/2/2015

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