Oral, hand and nail hygiene

Plaque is not simply dirt. It is a living film, a structured community of bacteria often called a biofilm, that sticks to the tooth and cannot be rinsed off with water. Its main offenders include Streptococcus mutans and Lactobacillus species. When sugar enters the mouth, these bacteria ferment it within seconds and release organic acids. The pH at the tooth surface can fall from about 7 to below 5, and below roughly pH 5.5 the mineral of enamel, hydroxyapatite, begins to dissolve. Saliva then buffers the acid and supplies calcium and phosphate, so the mineral can partly grow back: this is remineralisation. Whether a cavity forms depends on the balance between the two processes. That is why the frequency of sugar matters more than the total amount: every snack starts a new acid attack that lasts twenty to thirty minutes, and repeated attacks eventually win. Nursing applications follow directly. Many medicines are sweetened, and many, such as antihistamines and antidepressants, dry the mouth by reducing saliva, which removes the natural buffer. Patients who are sedated, confused, tube-fed or receiving oxygen cannot clean their own mouths. A nurse who cleans the mouth twice a day and checks for white patches is doing infection prevention, not cosmetic care.

Plaque that is not removed begins to mineralise within about forty-eight hours, taking calcium and phosphate from saliva. The result is calculus, or tartar: a hard deposit that cannot be brushed away. Its rough surface is itself a trap, so more plaque settles on it and the deposit grows, which is why professional tartar removal is one step and not a cure. Around the gum margin the plaque causes gingivitis: the gums become red, swollen and bleed easily. If the process continues, the inflammation extends below the gum line to the tissues that hold the tooth — the periodontal ligament and the alveolar bone — and this is periodontitis, which destroys the attachment of the tooth and can eventually loosen it. The same bacteria explain halitosis. Anaerobic bacteria living at the back of the tongue and in periodontal pockets break down sulphur-containing proteins from food and saliva, releasing volatile sulphur compounds such as hydrogen sulphide and methyl mercaptan, which smell of rotten eggs and cabbage. Brushing the tongue and cleaning between the teeth therefore helps the breath. For a nurse, the practical lesson is that oral care is part of daily hygiene for every dependent patient, and that red or bleeding gums and persistent bad breath are findings to record and report, not to accept as normal.

Removing microorganisms from hands works by chemistry plus physics. Soap molecules have a water-loving head and a grease-loving tail; the tails bury themselves in the oily dirt and the heads face the water, so the dirt and the microbes trapped in it are lifted off the skin and suspended in the rinsing water. Friction supplies the physics: it reaches into the ridges of the skin and around the fingertips, where a still hand cannot. This is why soap and water beat water alone, and why the whole hand must be rubbed — palms, backs, between fingers, thumbs, fingertips, nails — for at least twenty to thirty seconds. Alcohol-based hand rub works differently: it denatures microbial proteins and acts faster, but it is not effective when the hands are visibly soiled or soiled with body fluids, when soap and water must be used instead. The World Health Organization reduces the health-care list to five moments: before touching a patient, before a clean or aseptic procedure, after a body fluid exposure risk, after touching a patient, and after touching a patient’s surroundings. The framework is not a memory game; it names the point where transmission happens. Nails are part of the same rule. The subungual space under a long nail holds far more organisms than the flat of the hand, is poorly reached by hand rub, and is almost impossible to clean. Artificial nails and chipped polish increase the load further. That is why health workers keep their nails short and clean, and why a shared nail cutter or razor blade is treated as a sharp: microscopic traces of blood can carry hepatitis B, hepatitis C or HIV.