Both "Zähne putzen" and "Zähne bürsten" are commonly used in German to refer to the act of brushing teeth. "Zähne putzen" directly translates to "cleaning teeth," while "Zähne bürsten" translates to "brushing teeth." Both phrases are widely understood and used interchangeably in everyday language. **

Good oral hygiene involves maintaining a routine of daily practices to keep your mouth clean and healthy. This includes brushing your teeth at least twice a day with fluoride toothpaste, flossing daily to remove plaque and food particles between teeth, and using mouthwash to kill bacteria. Regular dental check-ups and cleanings are also important to prevent and detect any oral health issues early on. Additionally, avoiding tobacco products and maintaining a balanced diet can contribute to good oral hygiene. **

Private health insurance typically does not cover teeth whitening procedures, as they are considered to be cosmetic treatments rather than medically necessary. However, some dental insurance plans may offer coverage for teeth whitening as part of a broader dental care package. It's important to check with your insurance provider to understand what specific dental treatments are covered under your plan. **

Based on the information provided, it is not possible to determine if the friend has poor oral hygiene. The fact that the friend has not visited a dentist in several years could indicate poor oral hygiene, but it could also be due to other reasons such as fear of the dentist, financial constraints, or simply not feeling the need to go. Without more information, it would be unfair to make assumptions about the friend's oral hygiene. **

Multipurpose solutions are designed to clean, disinfect, rinse, and store contact lenses. They are all-in-one solutions that can be used for various functions. Saline solutions are primarily used for rinsing and storing contact lenses, but they do not clean or disinfect them. Storage solutions are specifically designed for storing contact lenses and do not clean or disinfect them. **

The solution set within the solution set refers to a subset of solutions that satisfy additional constraints or conditions beyond the original problem. For example, if the original problem is to find all solutions to an equation, the solution set within the solution set could be the solutions that are positive integers. This subset is a more specific set of solutions that meet both the original criteria and the additional conditions. **

The choice of perm solution depends on the desired outcome and the hair type. For fine or color-treated hair, a gentle or acid perm solution may be recommended to minimize damage. For coarse or resistant hair, a regular or alkaline perm solution may be more effective in achieving long-lasting curls. It is best to consult with a professional stylist to determine the most suitable perm solution for your hair. **

A diluted solution is a mixture in which the concentration of the solute is reduced by adding more solvent. This results in a less concentrated solution with a lower amount of solute per unit volume. Diluted solutions are commonly used in various applications, such as in chemistry experiments, medical treatments, and industrial processes, where a less concentrated solution is required for specific purposes. The process of dilution is often achieved by adding a specific amount of solvent to the original solution to achieve the desired concentration. **