This keeps the oxygen levels in the mouth at a semi-stable homeostatic condition, which allows the bacteria to survive. Consequences of plaque build-up
Gingivitis
Gingivitis is an inflammatory lesion, mediated by host-parasite interactions that remains localised to the gingival tissue, it is a common result of plaque build-up around the gingival tissues. The bacteria found in the biofilm elicit a host response resulting in localized inflammation of the tissue. This is characterized by the cardinal signs of inflammation including a red, puffy appearance of the gums and bleeding due to brushing or flossing. Gingivitis due to plaque can be reversible by removal of the plaque. However, if left for an extended period of time, the inflammation may begin to affect the supporting tissues, in a progression referred to as periodontitis. : 96–97  The gingivitis response is a protective mechanism, averting periodontitis in many cases. Periodontitis
Periodontitis is an infection of the gums which leads to bone destruction around the teeth in the jaw. Periodontitis occurs after gingivitis has been established, but not all individuals who have gingivitis will get periodontitis. : 111  Plaque accumulation is vital in the progression of periodontitis as the bacteria in plaque release enzymes which attack the bone and cause it to break down, and at the same time osteoclasts in the bone break down the bone as a way to prevent further infection. This can be treated with strict oral hygiene such as tooth brushing and cleaning in between the teeth as well as surgical debridement completed by a dental professional.
There have been calls to reclassify sickle cell trait as a disease state, based on its malignant clinical presentations. Significance may be greater during exercise. Association with other medical conditions
Malaria
The sickle cell trait provides a survival advantage against malaria fatality over people with normal hemoglobin in regions where malaria is endemic. The trait is known to cause significantly fewer deaths due to malaria, especially when Plasmodium falciparum is the causative organism. This is a prime example of natural selection, evidenced by the fact that the geographical distribution of the gene for hemoglobin S and the distribution of malaria in Africa virtually overlap. Because of the unique survival advantage, people with the trait become increasingly numerous as the number of malaria-infected people increases. Conversely, people who have normal hemoglobin tend to succumb to the complications of malaria.The way in which sickle cell protects against malaria is attributed to several different things. One of the more common explanations is that the sickle hemoglobin inhibits the plasmodium parasite from infecting the red blood cells which reduces the number of malaria parasites to infect the host. Another factor is the production of heme oxygenase-1 (HO-1) enzyme, which is highly present in the sickle hemoglobin. This enzyme produces carbon monoxide which has been proven to protect against cerebral malaria. Established associations
Hematuria
Hyposthenuria
Renal medullary carcinoma, a cancer affecting the kidney, is a very rare complication seen in patients with sickle cell trait. Renal papillary necrosis (only considered "possible" by some sources)
Splenic infarcts at high altitude. Surgery may not always be necessary.