1. HARD TOOTH
TISSUE
REDUCTION
Prepared by:
Dr. Rea Corpuz

2. Hard Tooth Tissue
Reduction
 (1) Attrition
 (2) Abrasion
 (3) Erosion
 (4) Abfraction

3. Attrition
 loss of tooth structure
 caused by tooth-to-tooth
contact during occlusion +
mastication
 comes from Latin verb attritum
 action of rubbing against
another surface

4. Attrition
 some degree of attrition
is physiologic
 process becomes noticeable
with age
 pathologic
 begins to affect esthetic
appearance + function

5. Attrition
 following factors can
accelerate tooth destruction
 poor- quality or absent
enamel
• fluorosis
• environmental or
hereditary enamel hypoplasia
• premature contacts
(edge-to-edge occlusion)

6. Attrition
• intraoral abrasives
• erosion
• grinding habits

7. Attrition
 occur both in deciduous
+ permanent dentition
 most frequently
 incisal + occlusal surface
 lingual surface of anterior
maxillary teeth
 labial surface of anterior
mandibular teeth

8. Attrition
 Clinically:
 Large
 Flat
 Smooth
 Shiny Wear Facet

9. Attrition

10. Abrasion
 pathologic wearing away
of tooth structure
 restoration secondary to
mechanical action of an
external agent

11. Abrasion
 comes from the Latin verb
abrasum
 to scrape off
 implies wear or partial
removal through mechanical
process

12. Abrasion
 Etiology
 toothbrushing
• combines abrasive
toothpaste
• heavy pressure
• horizontal tooth
brushing stroke

13. Abrasion
 Etiology
 pencils
 toothpicks
 pipe stems
 bobby pins (hair grips)
 chewing tobacco
 cracking nuts
 biting fingernails

14. Abrasion
 Clinically:
 (tooth brush abrasion)
horizontal cervical
notches on buccal surface
of exposed radicular
cementum + dentin
 sharply defined margins
 hard smooth surface

15. Abrasion
 Clinically:
 (thread biting or use of
pipes or bobby pins)
rounded or V-shaped
notches in incisal edges of
anterior teeth

16. Abrasion
 Clinically:
 degree of lost is greatest
on prominent teeth
• cuspids
• bicuspids
• teeth adjacent to edentulous
area
 ocassionaly more advanced
on the side of arch opposite
dominant hand

17. Erosion
 loss of tooth structure
 caused by non bacterial
chemical process
 comes from Latin verb erosum
 to corrode
 gradual destruction of
surface by chemical or
electrolytic process

18. Erosion
 Acidic source:
 foods or drinks
 involuntary regurgitation
 voluntary regurgitation
(eg bulimia)

19. Erosion
 Clinically
 facial + palatal surfaces
of maxillary anterior teeth
 facial + occlusal surfaces
of mandibular posterior teeth
 (maxillary anteriors)
shallow spoon-shaped
depressions in cervical portion
of crown

20. Erosion
 Clinically
 (posterior teeth)
extensive loss of occlusal
surface

21. Abfraction
 loss of tooth structure
from occlusal stresses
 create repeated tooth flexure
with failure of enamel +
dentin at a location away
from point of loading

22. Abfraction
 derived from Latin words
ab + fractio
 away + breaking
 dentin is able to withstand
greater tensile stress than enamel

23. Abfraction
 when occlusal forces are
applied eccentrically to a
tooth
 tensile stress is concentrated
at cervical fulcrum
 leads to flexure
 produce disruption in chemical
bonds of enamel crystals in
cervical areas

24. Abfraction
 once damaged, the cracked
enamel can be lost or more
easily removed by erosion
or abrasion

25. Abfraction
 Clinically
 wedge-shaped defects
limited to cervical area
of teeth
 deep, narrow + V-shaped

26. Abfraction
 Clinically
 occasionally lesions are
subgingival
• site typically protected
from abrasion + erosion

27. Abfraction
 Clinically
 predominantly affects
• bicuspids facial
• molars surfaces
 greater prevalence in those
with brusixim

28. References:
 Books
Neville, et al: Oral and Maxillofacial Pathology
3rd Edition
• (pages 61-65)