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Tooth wear
Definition
Tooth wear is usually due to a combination of processes, the triumvirate of
abrasion, attrition and erosion with one of these predominating.
Abrasion is a loss of tooth substances from the friction of foreign body often
from a tooth brush.
Attrition is a loss of tooth substance due to tooth to tooth contact ex.
parafunctional activity nocturnal bruxism is the most common.
Erosion is the loss of tooth structure by chemical means usually acidic and
not associated with mechanical or traumatic factors.
Abfraction is defined as wedge shaped defect observed at the cement enamel
junction, as axial forces of the tooth tend to concentrate stress in this region and
cause microfractures and tooth tissue loss (must be distinguished from cervical
abrasion).
Prevalence in adults
According to many studies, up to 97% of all adults are affected, only 7%
was considered a pathological wear, tooth wear increases with age and a certain
amount is considered to be normal (physiological) due to ageing process.
Prevalence in children
According to many studies, children aged 5-15 years showed evidence of
tooth wear, 50% of children aged 5-6 years had evidence of tooth wear (erosion),
25% having dentin involvement.
Assessment
Measurement of tooth wear in general and erosion in particular is difficult,
mostly used in vitro and cannot be translated to the clinical environment, it can be
assessed by either physical or chemical methods, physical include scanning
electron microscope, digital image analysis, microradiography, profilometry
ultrasonography and laser scanning. Chemical methods include calcium and
phosphorus dissolution and hydroxyl apatite dissolution. Most analytic systems are
Preventive Dentistry
أ.م. ساهر سامي
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accurate but they must be done in vitro and are time consuming and are not
practical to be done clinically.
In vivo studies, the most popular index used is the Tooth Wear Index (TWI)
of Smith and Knight (1984), it scores from 0-4 on specified index teeth.
Abrasion
Most abrasion is located in cervical area of teeth associated with tooth
brushing. Incorrect or over vigorous brushing with abrasive tooth paste is the
etiological factor. Brushing force, bristle stiffness, frequency and time spent in
tooth brushing are all important factors.
There is strong evidence that abrasion increases if teeth are exposed to an
acidic erosive challenge and then brushing is undertaken shortly afterwards, also
different foreign objects can cause abrasion like pipe smoking, pen chewing or
bagpipes.
Attrition
Wear caused due to tooth to tooth contact during the normal function of
eating should be minimal, unless the diet is very abrasive, or other reasons as
bruxism, which is considered to be the most significant parafunctional activity of
the stomatognathic system. It can be defined as a habitual grinding, clenching,
gritting and gnashing of the teeth during the day or the night for nonfunctional
purpose (conscious or subconscious grinding can occur).
Another important thing put in mind is that the pattern of wear is used to
determine the age of the individuals in forensic dentistry, this can sometimes be
inaccurate due to absence of reliable data about diet which can play an important
role in wear.
Erosion
Erosion is a multifactorial in etiology, could be either intrinsic or extrinsic
factors.
Intrinsic source of acids:
1/ Gastro-esophageal reflux. Which due to:
1.
Increase gastric pressure:
a.
Obesity
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b.
Ascetic
2.
Increase gastric volume:
a.
After heavy meal
b.
Obstruction
c.
Spasm
3.
Sphincter incompetence:
a.
Hiatus hernia
b.
Diet
c.
Drugs as diazepam
d.
Neuromuscular ex. cerebral palsy
e.
Oesophagitis
2/ Vomiting due to:
1.
Psychosomatic:
a.
Stress induced psychogenic
b.
Eating disorders
c.
Bulimia nervosa
d.
Anorexia nervosa
2.
Metabolic and endocrine
a.
Uraemia
b.
Diabetes
3.
Gastro-intestinal disorders
a.
Peptic ulcer, gastritis
b.
Obstruction
c.
Nervous system disorders
d.
Cerebral palsy
4.
Drug induced
a.
Primary, ex. cytotoxics
b.
Secondary to gastric irritation e.g. alcohol, aspirin, non-steroidal anti-
inflammatory drugs
c.
Drug-induced xerostomia over an extended period may also influence
erosion
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Extrinsic sources of acid
There are many sources of acid from outside the body, which may affect the
dental tissues. Dietary practices are changing from the traditional three meals per
day to habits of ‘grazing’ and ‘snacking’. There has been an enormous increase in
soft drink consumption in children and adults. A significant association has been
shown between soft drink consumption and dental erosion, particularly, the bed-
time consumption of fruit-based drinks. There are also acidic foods and practices
that may be implicated such as high consumption of fruit, pickles, and sauces.
It is not only the pH of the food and drink that is important in the
development of erosion, but also the titratable acidity. This is the amount of alkali
that needs to be added to an acid to bring it up to a neutral pH. It, therefore,
represents the amount of available acid, and is an indication of strength and erosive
potential (grape fruit juice, apple juice, orange juice cause the most erosion
compared with cola and carbonated orange drinks).
Another extrinsic source is the life style influence, as encouragement to take
regular exercise may lead to increased consumption of acidic drinks and some of
the sports individuals not only consume acidic beverages, but also those that
contain much sugars, ex. swimmers and cyclists have been reported to show high
level of dental erosion, an unhealthy life style implicated in the dental erosion
include uses of drugs ex. methamphetamine which reduces salivary flow and
increase dental erosion.
Prevention of tooth wear
Prevention of abrasion
If the main etiology is incorrect tooth brushing and/ or the use of overly
abrasive tooth brush, then the technique and paste can be changed. Sometimes
abrasion can be a problem if it is related to professional activity ex. wind
instruments player.
Prevention of attrition
If related to parafunctional activity, it has been proved to be impossible to
totally stop nocturnal bruxism activity. Also construction of a mouth guard or
occlusal splint, which prevent tooth to tooth contact that cause attrition. Occlusal
adjustment is not effective in treatment.
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Prevention of erosion
Loss of tooth surface is a multifactorial process and education is the first
step in the line of defense. Diet history can be taken from the patient.
After analysis of the diet, Give appropriate dietary counseling:
limit acids and drinks to meal times.
Reduce frequency.
Avoid acidic substances last thing at night.
Do not hold or swish acidic drinks in your mouth.
Avoid sipping acidic drinks, use a straw.
Avoid tooth brushing immediately after an erosive challenge
(vomiting, acidic diet).
Avoid tooth brushing immediately before an erosive challenge, as the
acquired pellicle provides a protection against erosion.
Use a soft tooth brush.
Use a low abrasive fluoride-containing tooth paste, since high
abrasive tooth paste may destroy the pellicle.
Avoid tooth pastes or mouth washes with too low pH.
After acid intake, stimulate saliva flow with chewing gum or
lozenges.
Use chewing gum to reduce post prandial reflux.
Refer patients or advise them to seek appropriate medical attention
when intrinsic causes are involved.
Finish meal in something alkaline like piece of cheese.
If reflux or vomiting are occurring, then rinsing the mouth with water and
sodium bicarbonate helps to neutralize the oral environment. People who have
vomited often rush off to clean their teeth. This is quite the wrong thing to do and
should be advised against. It has been shown that if teeth have been subjected to an
acidic attack and are then brushed, up to five times as much enamel is removed. If
reflux is occurring during sleep then an occlusal guard containing sodium
bicarbonate can be used in adults or teenagers.
The effects of tooth wear that require treatment are esthetic, tooth sensitivity,
prevention of pulp exposure, fractured teeth restoration and crowning.