DENTAL EROSION

Erosion is the irreversible loss of tooth substance brought about by a chemical process that does not involve bacterial action. 

There have been some disagreements in dental field pertaining to “Dental Erosion”. Grippo and Simring have decried the use of this term. They suggest that erosion refers to loss of material from the action of fluids against a structure, as in beach erosion from water, and that no such mechanism exists in the mouth.  So, it is inappropriate terminology, and the term erosion should be discarded from the dental literature. Abrahamsen and others disagree, and properly point out that Webster defines erosion as a “wearing away as acid erodes metal.” Gould Medical Dictionary defines it as “superficial destruction of a surface area by inflammation or trauma.” Gould also describes dental erosion as “loss of tooth surface due to a chemical process.”

In material science, erosion is viewed as wear caused by flow of fluid with abrasive particles. “Corrosion” is a physico-chemical or electrochemical process.  Hence, erosion is also called  “corrosive wear”.

Enamel dissolves in distilled water,  but not in saliva, which, at pH 7, is supersaturated with respect to the teeth, unless chelation takes place, i.e. organic molecules bind calcium ions bicovalently.  At a pH ∼5.5 (or <6) saliva is undersaturated and dissolves the enamel: the more acidic the environment, the greater is the enamel surface loss and softening.

Rinsing with 2% citric acid (pH 2.1) makes the saliva undersaturated for 2 minutes. As the acid is washed away and neutralized by the saliva the oral environment returns to a state of supersaturation.

 The clinical pattern of tooth wear often suggests the source of acid as either intrinsic, extrinsic or occupational (environmental):

• Intrinsic acid is caused by gastric acid arising from gastro-oesophageal reflux disease (GORD),  recurrent vomiting in alcoholism,  eating disorders or food regurgitation. Tooth surface loss is commonly seen on the palatal surfaces of the upper teeth and the occlusal surfaces of posterior teeth, particularly in the lower arch.

• Extrinsic acids are largely of dietary origin, mainly from carbonated drinks, citrus fruit, fruit juices and acidic foodstuffs (e.g. vinegar/pickles). Tooth surface loss is commonly seen on the buccal and occlusal surfaces.

 

• Occupational erosion is now less common due to stringent health and safety legislation but historically occurred in chemical engineering, e.g. battery acid manufacture.

Management

The first stage in management of tooth wear is to identify the aetiology and, where possible, modify or preferably eliminate the causative factor(s). This may involve education of the patient and provision of:

• Dietary counselling.
• Oral hygiene advice.
• General medical and occasionally psychiatric advice and treatment (eating disorders).

Thereafter, intervention is governed by the extent of the damage sustained by the dentition. Simple maintenance and monitoring are often the best policy where limited damage has occurred, and may include: 

• Analysis of accurate study casts and/or simple silicone indices.
• Provision of protective appliances (soft vinyl or hard acrylic mouth guards).
• Adhesive restorations applied to the worn surfaces.
• Treatment of sensitivity, topical fluoride application and oral hygiene advice.

Active treatment requires careful planning, looking at all aspects of the dentition and its prognosis. It may involve:

• Conventional or adhesive intracoronal restorations .
• Extracoronal restorations, ranging from veneers/ onlays/shims to full coverage crown and bridge- work.
If significant loss of tooth substance has occurred and dentoalveolar compensation has occurred, a reorganised approach may be considered.

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References: 

1. Restorative Dentistry, Paediatric Dentistry and Orthodontics. Volume TWO  (3rd edition) Peter Heasman. Edinburgh London New York Oxford Philadelphia St Louis Sydney Toronto 2013

2. Functional Occlusion: From TMJ to Smile Design. 2007 by Mosby, Inc., an affiliate of Elsevier Inc.Peter. E. Dawson. St. Louis, Missouri. 

3. Dugmore CR, Rock WP. The prevalence of tooth erosion in 12-year-old children. Br Dent J. 2004;196(5):279-282.

4.“Quintessentials of Dental Practice – 34 Clinical Practice – 4 Dental Erosion. R Graham Chadwick. R Graham Chadwick. “ 2006 Quintessence Publishing Co. Ltd., London”

5. Pathology of the Hard Dental Tissues. Albert Schuurs. ACTA (Academic Center for Dentistry Amsterdam) Amsterdam. John Wiley & Sons, Ltd, 2013 

6. Dental Erosion From Diagnosis to Therapy. Adrian Lussi Bern.2006 by S. Karger AG, P.O. Box, CH–4009 Basel (Switzerland)