Tooth Discoloration

• University of Texas Health Science Center at San Antonio — San Antonio, Texas, United States

• Hellman Dermatology clinic — New York, United States

• Yara Attia — Cairo, Egypt

• Zeliha Gonca Bek Kürklü — Adana, Sarıcam, Turkey (Türkiye)

• Arizona School of Dentistry & Oral Health — Mesa, Arizona, United States

• University of New England — Portland, Maine, United States

• Salus research — Fort Wayne, Indiana, United States

Not specified

• Fujian Medical University — Fuzhou, Fujian, China

• Universidade Federal de Sergipe — Aracaju, Sergipe, Brazil