Clinical Evaluation and Laboratory Wear- Testing Methods - Dental Biotribology - page 35

Table 2.7 Classifi cation of wear situations in dentistry

Type of
wear Interoral wear event Lubricant Substrate Opponent Abrasive

Physiological
causes of wear
Noncontact wear

Three-body Saliva/food Tooth/restoration — Food

Direct contact
wear

Two- body Saliva Tooth/restoration Tooth/restoration —

Sliding contact
wear

Two- body Saliva Tooth/restoration Tooth/restoration —

Pathological causes
of wear
Bruxism Two- body Saliva Tooth/restoration Tooth/restoration —

Xerostomia Two- body — Tooth/restoration Tooth/restoration —

Erosion — Saliva Tooth/restoration — —

Unusual habits Two- body Saliva Tooth/restoration Foreign body —

Prophylactic causes
of wear
Toothbrush and
dentifrice

Three-body Water Tooth/restoration Toothbrush Dentifrice

Prophylactic
pastes

Three-body Water Tooth/restoration Polishing cup Pumice

Scaling and
cleaning

Two- body Water Tooth/restoration Instrument —

Cutting, fi nishing,
polishing
Cutting burrs/
diamonds

Two- body Water Tooth/restoration Burr —

Finishing burrs Two- body Water Tooth/restoration Burr —

Polishing pastes Three-body Water Tooth/restoration Polishing cup Abrasive

slurry

Source : From Crothers [ 8 ]

clinical problem, with various epidemiologic studies suggesting prevalence estimates
of up to 97 %, with around 7 % of the population showing pathological wear requir-
ing treatment [ 6 ]. The main categories of wear that contribute to the destruction of
natural teeth and artifi cial materials are classifi ed as follows [ 7 ]: physiological wear
(vital life functions); pathological wear (disease and abnormal conditions); prophy-
lactic wear (preventive conditions); and fi nishing procedure wear. An overview is
provided in Table 2.7 .
Physiological wear, inevitably due to the function of mastication [ 8 - 11 ], is sur-
face degradation that results in a progressive, very slow loss of the convexity of
tooth cusps, which manifests as a fl attening of both cusp tips on the posterior teeth
and incisal edges on the anterior teeth for mammals. Compared with physiological
wear, some pathological factors can cause excessive wear of teeth and restorations
[ 9 ]. Clinical reports show that wear usually becomes signifi cantly severe due to ero-
sion, bruxism, xerostomia, and so on. Pathological wear can also be caused by