Final answer:
Lesions under dentures are primarily caused by dental caries and gingivitis due to microbial infections. Poor dental hygiene can lead to tooth decay, inflammation, and gum recession, eventually progressing to periodontal disease which may result in tooth loss.
Step-by-step explanation:
Principal Causes of Lesions Under Dentures
The principal causes of lesions under dentures, such as dental caries and gingivitis, are primarily due to microbial infections that damage the structures of the teeth and gums. Dental caries occur when bacterial biofilms or plaque develop on teeth, producing acids that gradually dissolve tooth enamel and dentin, potentially causing an abscess if it reaches the pulp. In cases of gingivitis, plaque accumulation leads to bacterial colonization and inflammation, causing gum irritation and bleeding. Without proper dental hygiene, gingivitis can progress to periodontal disease, a more serious condition where gums recede and teeth may eventually become loose or be lost. Various bacteria such as Porphyromonas, Streptococcus, Actinomyces, and others contribute to these infections, which may require professional dental cleaning and possibly antibiotics for severe cases.