Microorganisms

Question 1

Bacteria

Answer 1

single celled organisms which are only visible under a light microscope. They also have rigid outer walls which helps to determine their shape. Also, they favour undesirable conditions and when they are not favourable, they survive as spores. The types are Bacilli - rod shaped with pointed ends
Lactobacilli - rod shaped with round ends
Spirochetes - spiral shaped
and Cocci -circular (staphylococci live in clusters and Streptococci live in chains)

Question 2

diseases they produce

Answer 2

Bacteria reproduce rapidly by fission and collect in colonies which may be seen by the naked eye. For example, dental caries and periodontal disease are caused by a bacterial infection. They are only killed by sterilisation within the dental environment.

Question 3

Fungi

Answer 3

Fungi is larger than bacteria but only visible under a light microscope. It is a type of microscopic plant similar to mushrooms and is reproduced by budding or by spore production. They grow by producing extensive branching network across tissues (hyphae)

Question 4

diseases they produce

Answer 4

Candida albicans is a fungus which grows well beneath poorly cleaned dentures and in the mouths of patients with ill health. This is the only fungal infection of importance to dental as it causes oral thrush, denture stomatitis and angular cheilitis.

Question 5

Viruses

Answer 5

Viruses are very small (ultramicroscopic) and are only visible under an electron microscope. They must live within a host cell and exist as a protein capsule containing necessary chemicals to reproduce.

Question 6

diseases they produce

Answer 6

It is this protein capsule that causes our body to react against them and is unique to each virus. Examples include Hepatitis, Measles and Mumps however, vaccinations have been developed of immunity against these. Furthermore, they are unaffected by antibiotics, but some can be treated using antiviral drugs.

Question 7

Spores

Answer 7

Spores are an organism that remains inactive throughout unfavourable conditions and it can then merge into its pathological state.

Question 8

diseases they produce

Answer 8

Similar to bacteria, fungi and viruses, but it remains inactive until thriving in favourable conditions and then can cause diseases relating to bacteria, viruses and fungi. Spores are not easily killed other than by dry heat, autoclaving, ethylene oxide gas or gamma irradiation.

Question 9

Direct transmission

Answer 9

One route of transmission is direct contact with blood or bodily fluids. This includes a sharp injection with a contaminated instrument therefore diseases are transmitted by this wound.

Question 10

Indirect transmission

Answer 10

indirect contact with contaminated instruments as pathogenic microorganisms have thrived on an instrument, equipment or environmental surface.

Question 11

Droplet transmission

Answer 11

which spray or spatter containing microorganisms travels a short distance before settling on the mucous membrane of the eyes, nose or mouth but can also include ingestion and inhalation.

Question 12

Airborne transmission

Answer 12

inhalation of evaporated microorganisms that can remain airborne for extended periods of time as aerosols such as from ultrasonic equipment and hand pieces.

Question 13

Pathogenic

Answer 13

Pathogens are microorganisms that are harmful to human health as they are disease carrying. These are the type of microorganisms that cause the risk of cross contamination of items and people as they can cause serious harm including many occupational diseases.

Question 14

Non-pathogenic

Answer 14

Non-pathogenic microorganisms live in the body without causing any diseases, so they are not containing great risk to human health within the dental environment and do not pose a risk of cross contamination of infection.