**Core Concept**
The concept of lingual orthodontic appliances refers to the use of orthodontic devices that are placed on the lingual (tongue) side of teeth, providing a discreet and aesthetic alternative to traditional orthodontic treatments. This approach aims to minimize visibility while achieving effective tooth movement and alignment.

**Why the Correct Answer is Right**
The introduction of lingual orthodontic appliances is attributed to Dr. Kurt (also known as Kurz) in the 1960s. He designed and developed the first lingual orthodontic system, which involved fabricating custom-made appliances that were bonded to the lingual surfaces of teeth. This innovation marked a significant shift in orthodontic treatment, offering patients a more discreet and comfortable option for correcting dental irregularities. The use of lingual appliances involves a unique technique that requires precise craftsmanship and attention to detail to ensure optimal results.

**Why Each Wrong Option is Incorrect**
**Option A:** Atkinson's contributions to orthodontics are notable, but he is not credited with introducing the concept of lingual orthodontic appliances.
**Option B:** Mershon's work in orthodontics has focused on other areas, such as orthognathic surgery and facial growth, but not on lingual appliances.
**Option C:** Johnson has made significant contributions to orthodontic research and education, but is not associated with the development of lingual orthodontic appliances.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that lingual orthodontic appliances require a high degree of craftsmanship and customization to achieve optimal results. This approach is particularly suitable for patients who desire a discreet and aesthetic orthodontic treatment option.

**Correct Answer:**
✓ Correct Answer: D. Kurz