Lab 35: Oral Microbiota

Oral microbiota=normal flora found in the oral cavity 

-these organisms colonize the teeth, gums, tongue, cheek mucosa, and salivary glands where warm, moist, nutrient-rich and diverse oxygen environments are present 

-most common oral bacteria= streptococci, but hundreds of different species are present, including yeasts  

-since bacteria are firmly attached in the oral cavity, they resist removal by the abrasive actions of the teeth, tongue and food, and by the flow of saliva

-the main method of removal is sloughing of mucosa, something teeth can’t do, bc of this, the teeth harbor a great abundance of bacteria

-teeth form biofilms= plaque

-inside each gram of plaque- billions of bacteria, esp. in pits and crevices

-plaque resists penetration of saliva, which contains lysozyme and other antimicrobial factors 

-plaque build up is important in 2 oral diseases:

1. dental caries (cavities)

2. Periodontal disease 

In this lab= we gram stain smears of plaque from a tooth surface and from gingival crevice (where gums meet teeth) to examine diversity of oral microbiota 

Note* 

your teeth should have less bacteria then your gingival crevice

-How to Identify slides from the mouth, they will contain:

          1. Diversity- rods/cocci, gram +/- etc.

           2. Cheek cells= large purple epithelial cells from mouth

Here are some examples of Gram Stained Oral microbiota (note presence of cheek cells)