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TYPES OF DENTITION Veterinary dental nursing procedures TYPES OF DENTITION.

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Presentation on theme: "TYPES OF DENTITION Veterinary dental nursing procedures TYPES OF DENTITION."— Presentation transcript:

1 TYPES OF DENTITION Veterinary dental nursing procedures TYPES OF DENTITION

2 5888H - Veterinary Dental Nursing

3 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Function of teeth Defence Acquiring food –Picking up –Catching –Killing Holding food Breaking down food –Cutting (shearing) –Crushing (grinding)

4 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Evolution of teeth From skin From fish scales? All vertebrates have evolved from toothed ancestors (except Agnatha)

5 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Shark teeth – new rows

6 TYPES OF DENTITION 5888H - Veterinary Dental Nursing In the mammalian embryo Bud forms in oral mucosa –First completely buried then resurfaces

7 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Evolutionary classifications tooth location anchorage number form number of replacement sets cycles of replacement

8 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Tooth location Fish –on most jaw/palate bones Mammals –Premaxilla-Maxilla –Mandible

9 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Side of jaw (pleurodont) –eg sharks Crest of jaw (aerodont) Tooth socket (thecodont) –attached in a socket with a projecting crown Tooth location

10 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Number of teeth Many (polyodont) – primitive vertebrates Several (oligodont) – trends towards this. Toothless vertebrates became toothless by either loss in number of teeth or by progressive reduction in the size of each tooth. For example, groups such as birds, turtles, and some anurans result from reduction in tooth size as evidenced by presence of teeth in the embryos of these groups. None (aphyodonty) – no teeth erupt, e.g. armadillos and anteaters.

11 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Tooth Variation Single shape (homodonty) –The primitive condition,with teeth of a uniform, conical appearance –Most non-mammalian vertebrates (Crocodilians have some variation) 2 or More shapes (heterodonty) –The teeth may be modified for crushing (bunodont), grinding (selenodont, lophodont ), slashing (canine), shearing (secodont), poison conducting. Mammals

12 TYPES OF DENTITION 5888H - Veterinary Dental Nursing No. of Sets of Teeth per Lifetime Many –primitive vertebrates were characterised with continual replacement of teeth eg sharks (polyphyodont) Several –several sets of temporary teeth before a final set of permanent teeth eg crocodiles (oligophyodont) Two –eg cat /dogs/humans (In all mammals molars are by definition permanent teeth. Premolars may be deciduous) (biphyodont) One –eg moles (monophyodont)

13 TYPES OF DENTITION 5888H - Veterinary Dental Nursing How to make a tooth last For carnivores – short crown –brachydont shape For herbivores – long crown –hypsodont shape –Either Continual growth, or Slow growth & slow eruption (horse)

14 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Closed & Open Roots Closed Open

15 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Open & Closed Roots Open root = continued growth –Enamel extends all way into socket (elodont) Closed root = ceased growth –Enamel extends only over crown Closed slowly with continued eruption throughout life –Long crown but shortens as tooth worn down and erupts

16 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Closed Roots (e.g. cat, dog, man)

17 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Open Roots (rabbit)

18 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Replacement patterns Vertical –e.g. horse Horizontal –e.g. elephant

19 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Elephant Horizontal replacement

20 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Horse Vertical replacement

21 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Snakes

22 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Snakes

23 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Snakes

24 TYPES OF DENTITION 5888H - Veterinary Dental Nursing Upper Pads Sheep & Cattle

25 TYPES OF DENTITION 5888H - Veterinary Dental Nursing The End


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