Conservative Dentistry and Endodontics

Mobility is due to loss of alveolar bone support.
Pulpotomy is a process designed to remove the infected pulp in the coronal pulp so that vitality of the pulp is maintained in the radicular part. This is not indicated when mobility is already present.

Amalgam alloys can be classified under various headings. One of them is based on the shape of the alloys particles. They can be either Lathe cut or Spherical or Spheroidal.

Other solvents are: methylchloroform, carbon - disulfide, carbon - tetrachloride, benzene, eucalyptol oil, rectified white turpentine.

Irreversible pulpitis can be divided, based on the duration of the illness, into acute and chronic types.

Lactobacilli have both aciduric and acidogenic potential, so they are crucial for progression of caries.

Pins are used in restoration to improve the retention form.
Cemented pins are retained passively in a pin hole which is from 0.001 to 0.002 inches bigger in diameter than the pin.
Hence, there is no stress during the pin placement and that is why this is indicated in RC treated teeth.

Taper angle is intended to approximate the desired occlusal divergence of the lateral wall of the preparation. It does not affect the bur performance.

Discoloration of the teeth can be either extrinsic or intrinsic.
Extrinsic stains are due to dietary sources or by habits.
Intrinsic stains can be due to various causes:

1. Enamel hypoplasia,
2. Fluorosis,
3. Tetracycline staining,
4. Pulpal hemorrhage

Permeability of the dentin depends on the diameter and the length of the tubules.
Convection coefficient relates to the amount heat transferred through the fluids. This convection has no bearing on the permeability.

Enamel hatchet is a chisel. It is similar in design to the ordinary hatchet but blade is larger, heavier and beveled only on one side. It is single plane instrument.
It does not have a curve in the blade. This is seen in the gingival marginal trimmer.

Active carious lesions means bacteria are actively demineralizing enamel/dentin.
The surface would be soft and cheesy, dark in colour and there will be pain on excavation.
In a nonactive lesion, the bacteria and the host will be in the state of equilibrium. The tooth surface will be dark but hard.

In an amalgam restoration, all the internal line angles are rounded because the stress concentration needs to be reduced. This is one of the principles of resistance form.

In a non active lesion, the bacteria and the host will be in the state of equilibrium. The tooth surface will be dark but hard. There is no demineralization at this stage.

GP becomes soft at temperature above 64^oC. Option a, b and d use heat for sterilization. GP can not be heat sterilized, hence it is submerged in 5% solution of NaOCI for one minute.  Then, it should be rinsed with ethyl alcohol to remove crystalline NaOCI before obturation. Otherwise, this will interfere with the seal of obturation.

Even though ultrasonic detection also can help in diagnosis of incipient lesion, digital FOTI is the only dental diagnostic imaging instrument to be approved by the FDA for detection of incipient, frank and recurrent caries.

Porcelain laminates are permanent aesthetic restoration, which mark the progress in acid etch, bonding and aesthetic restorative techniques.
The bond of etched porcelain laminates to enamel is considerably stronger than any other laminate system.

E. faecalis is the most commonly found organism in failed root canal cases. It is rarely found in infected but untreated root canal cases.

A deep cavity to be restored with composite, a calcium hydroxide liner and a resin modified GIC base is placed.

The endodontic instruments commonly used for BMP include the files and the reamers. The files are of 2 types- kerr type and the Hedstroem type.
Files have more flutes per mm as compared to reamers. File: 1.5-2 flutes per mm. reamers: 0.5-1 flute per mm. Also, files have square cross section while reamers have triangular cross section.

Four canals in mandibular first molar will be - mesiobuccal, mesiolingual in the mesial root and distobuccal, distolingual in the distal root.

Beelby's layer is formed once the amalgam is polished.

It was first introduced by Buonocore in 1955. He advocated the use of phosphoric acid to etch the enamel. The concentration used is 37%.

Because the apical pulpal circulation is not disrupted, pulp necrosis in the apical segment is extremely rate. Pulp necrosis develops in the coronal segment owing to the displacement but occurs in only 25% of the cases.

The gel form is preferred over the solution form as it is easier to keep it in one place without spreading.

Dental pulp is in many ways similar to the connective tissues of the body.
It houses a number of tissue elements, including nerves, vascular tissues, CT fibres, ground substance, interstitial fluid, odontoblasts, fibroblasts, immune competent cells and other cellular components.