Dental anatomy note book ... / by Douglas Gabell.

  • Gabell, Douglas Phillimore.
Date:
1909
Catalogue details

Licence: In copyright

Credit: Dental anatomy note book ... / by Douglas Gabell. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    11/76
    ENAMEL Is very hard, brittle, bluish-white, and semi-translucent. And composed of Caleified Prisms in a Calcified Matrix. CHEMICAL COMPOSITION. Organic Matter, (mucin :>) NONE. Calcium phosphate \ Salts Calcium carbonate 1 Calcium tiuoride / ^ Magnesium phosphate } Water, (chemically combined with the salts) 5 % THE MATRIX Is very small in amount, absolutely calcified, but is more easily dissolved by acids than the prisms. THE PRISMS Ai'e long hexagonal varicose rods, solid, and absolutely calcified, but the centre is usually more easily dissolved by acids than the external part. In the Eel . Manatee Sciuridse Beaver . Porcupine Leporidse Muridse . Man . No structure is visible. Straight prisms. Lamellate thus:— Lamellate and liexuous prisms thus Lamellate and spiral prisms. No lamellae, only flexuous prisms. Serrated prisms. Straight or slightly flexuous prisms. The Transverse Strise of prisms are due to either:—1. Varicosity of the prisms. 2. Intermittent calcification. 3. Decussation of the prisms. 4. Boedecker's thorns. or 5. The action of acids (balsam). In all Marsupials (bar the Wombat), some Rodents (Jerboa), some Inseetivora (Sorieidse), Hyrax, and some Fishes (Barbel, Porbeagle Shark), the central portions of the prisms remain Unealcifled, i.e., Tubular Enamel. Sometimes this happens at the inner parts of the enamel only, sometimes at the outer part (Sargxis) ; often this condition is irregularly distributed. LEARN TO RECOGNISE and explam : BROWN STRI/E OF RETZIUS. SCHREGER'S LmES. TOMES' LINES. BOEDECKER'S THORNS.' PIGMENT IN THE ENAMEL. IRREGULAR FISSURES NEAR THE DENTINE. DISTRIBUTION OF ENAMEL. Absent from Edentata, Narwal, some Cetaeians, Reptiles, and Fish. Tip only in Hake, Eel, Elephant's tusk. All over crown in Man and most Mammalia. ■c , • T 1 r- , ^1 ) Rodents' incisors, l^ront or sides only of tooth m ■] ■ „ I uanmes of Sumae, Iguanodon. LEARN HOW TO SHOW:- ENAMEL PRISMS, TRANSVERSE STRI/E, STRI/£ OF RETZIUS, SCHREGER'S LINES. /i