Final answer:
Sterilization of carious dentin without pulp injury is achieved through safe and effective antiseptics. While historical comparisons used phenol as a standard, it is no longer preferred due to toxicity. Safer alternatives like 4-hexylresorcinol in some mouthwashes and 70% ethyl alcohol are commonly used, but 4-hexylresorcinol is not listed, leading to 'None of the above' being the correct answer.
Step-by-step explanation:
The sterilization of carious dentin without pulp injury can be achieved through the application of certain chemical agents that have antiseptic properties. The effectiveness of these agents is historically compared to phenol, which was used extensively in the past but is no longer preferred due to its toxicity and potential to cause severe burns and systemic poisoning. One of the safer alternatives to phenol that is powerful in germicidal activity and has fewer side effects is 4-hexylresorcinol, often found in some mouthwashes and throat lozenges.
Regarding alcohols, they work by denaturing proteins and disrupting membranes, leading to cell lysis. A 70% aqueous solution of ethanol is commonly used as a disinfectant and antiseptic, as it is more effective in the presence of water which permits deeper penetration into cells. Absolute alcohol, or 100% ethanol, is less effective for microbial control on tissues because its rapid coagulation of surface proteins hinders effective penetration of cells.
Therefore, in the context of treating carious dentin, it is critical to choose an agent that will disinfect without harming the delicate pulp tissue underneath. Given the requirements for effectiveness and safety, 4-hexylresorcinol, an alcohol-based antiseptic, maybe a suitable choice even though it is not listed among the options provided in the question. So the correct answer would be 'None of the above' (E).