Final answer:
Chemically induced changes in hair that alter the natural texture, curl, or wave pattern are considered permanent, as they involve the restructuring of disulfide bonds within the hair. Temporary methods, affecting hydrogen bonds, do not create lasting changes.
Step-by-step explanation:
Chemically infused services that alter the natural texture, curl, or wave pattern in the hair are considered permanent. This is due to the fact that such services disrupt and reconfigure the disulfide bonds within the hair strands, which are responsible for the hair's structure.
These permanent changes can be achieved through thermal or chemical means. In a chemical method, specific chemicals are applied to the hair, which is subsequently shaped around forms, either to produce curls (as in perming) or to straighten it. The chemical reaction involved may result in the hair being permanently curled or straightened, as the newly-formed disulfide bonds set the hair in its new shape.
Temporary methods also exist and work by disrupting hydrogen bonds when hair comes in contact with water. However, once the hair dries or is washed, these changes disappear and the hair returns to its natural texture due to the temporary nature of hydrogen bond disruptio