9. Tooth Wear.pdf

8/16/2019 9. Tooth Wear.pdf

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Teeth WearEtiology and Management

SDS 320


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Definition:

Wear is a natural process that occurswhenever two or more surfaces move in

contact. It is, therefore, considered thatwear of human natural dentition, to acertain extent, is a predictable

physiological process result fromcontinuous sliding contact betweenopposing teeth.


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Acceptable and pathological levels of wear.

Tooth wear can be regarded as pathological in the followingconditions:

1 Loss in vertical dimension

2 Pulpal symptoms or pulp exposure.

3 Change in appearance of teeth.

5 Accelerated and high wear rate relative to age.

6 Loss in posterior occlusal stability resulting in

a- Increased tooth wearb- Mechanical failure of teeth restorations

c- Hypermobility and drifting


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EtiologyThe terms “ tooth surface loss” and “toothwear” are interchangeable and embrace all theetiological conditions that cause tooth wearwhich occur in the absence of dental plaqueand caries and trauma. Conditions that causetooth wear include attrition, abrasion, erosionand abfraction.


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AttritionAttrition is defined as the loss/wear of tooth structureor restoration caused by mastication or contact

between occluding or a proximal surfaces (tooth totooth contact).

Predisposing factors:1- Parafunctional habits

2 –Developmental defects

3- Coarse diet

4- Coarse porcelain restorations

5- Lack of posterior support


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Attrition of lower incisor teeth that match palatalsurfaces of maxillary incisors in excursive

movements


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AbrasionAbrasion is the wear of tooth substance through

biomechanical friction process other than tooth contact .Predisposing factors

1- Vigorous horizontal tooth brushing

2- Nail biting, pen biting and pipe smoking.

4- Abrasive tooth pasts and powders

3- Denture clasps in RPD.5- Hard tooth brushes


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Clinical appearance Angular “V” shaped cervical lesion.May affect teeth with prominent in the left side ofright handed patients and vice versa.Affect labial surfaces of prominent teeth ….canines


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Occlusal stresses (Abfraction )

Defined as non carious cervical lesionscaused by tensile stress generated fromocclusal loading, and micro fracture ofcervical enamel rods


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• Flexure and ultimate fatigue of enamel and dentine

of susceptible teeth away from the point of loading.Occlusal stresses explain why cervical lesion not

present on teeth adjacent to primary site whichseem to discount tooth-brushing abrasion orchemical erosion as sole causes of tooth loss.

• The loss of tooth substance may depend on thedirection, magnitude, frequency, duration andlocation of the force on the teeth.

Mechanism (Stress corrosion theory)


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• If occlusion is not ideal or if heavy occlusaltrauma is present, significant lateral forces aregenerated, which cause the tooth to bend andcreate compressive and tensile stresses on tooth

structure. The region under greatest tensilestresses is the fulcrum located around thecementoenamel junction. Tensile forces disruptchemical bonds between hydroxyapatite crystalsin enamel.


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Erosion

Erosion is the progressive loss of hard dentaltissues by chemical process not involving bacterialaction.

Factors that cause erosion:1- Dietary

2- Regurgitation

3- Environmental4- Flow of saliva

5- Medications


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Dietary Erosion:

• Citric acid in soft drinks and fruit juices.

• Slimness: acidic sugar free drinks

• “healthy eating”: fruits

Regurgitation:

• Involuntary regurgitation :

1- Gastrointestinal problems

2- Chronic alcoholism

• Voluntary regurgitation

1- Anorexia nervosa

2- Bulimia nervosa


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Chemicl pH


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Environmental• Tooth wear caused by acid exposure in the

environment or under occupationcircumstances such as battery-making workers,

picklers, miners

• Usually affect labial surfaces of maxillary andmandibular incisors


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Saliva flow rate• Saliva has a buffering and lubricating effect

• Reduced flow and rate: Xerostomia, Sogrensyndrom, radiotherapy


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Clinical Features

• Rounded less well defined margins than attrition

• Enamel has matted surface

• Dentine may be exposed with continuous erosion(Cupping)

• Palatal erosion related to intrinsic and extrinsic acids

• Increase in translucency of anterior teeth

• Cervical surfaces may be more prone to erosion because these areas close to the gingiva are less self-cleaning and food and beverages may be harbored onthe tooth surface for longer periods of time


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Clinical Problems associated with tooth wear

• Aesthetics

• Conservation of tooth structure

• Sensitivity and pain

• Inter-occlusal space: dento-alveolar compensationoccurs in 80% of patients with tooth wear. i.e, free

way space and resting facial height unaltered

• Patient compliance and expectations


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Management Immediate Therapy

Aimed to:

1. Relieve sensitivity and pain

2. Identify etiological factors

3. Protect remaining tooth tissue


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Clinical Indications for Restorative management :

• Biological

- Loss of tooth substance leading to irregular margins

- Pulpal exposure

- Weakening of tooth structure

• Functional

- Reduced masticatory function

• Aesthetic

- Aesthetically unacceptable


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Cervical Tooth Wear Management

• Not all lesions require restorations.• Restore if esthetic, sensitivity or structural concerns

prevail.

•

Composite vs. glass ionomer.• Lesion margins in enamel-microfine composite.• Lesion margins involve cementum or dentine-Dentine

bonding with composite or GI.

•

Deep cervical lesion-layered technique (GI andcomposite)


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9. Tooth Wear.pdf

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