Teeth preparation
calculus
DENTAL PLAQUE
The selected teeth root lengths were measured from the cervical line of teeth to the apex using Digital caliper (Sedradent, TDV Co. Pomerode, Santa Catarina, Brazil); they were more or less 13 mm long (± 0.5 mm). Teeth were then mechanically cleaned with aid of hand scaler (Nordent Manufacturing Inc., 610 Bonnie Lane, Elk Grove Village, IL 60007, T: 800.966.7336 US & Canada)to remove remaining dental plaque, calculus, and periodontal tissues [Eighteeth curing pen (Changzhou Sifary Medical Technology Co., Ltd.) was used to transilluminate the specimens at light intensity of 600 mW/cm2 and wavelength of 385 nm–410 nm to ensure they were devoid of any internal or external crack lines [Teeth were embedded in auto-polymerizing acrylic resin blocks, in cylindrical metallic molds, along with their vertical long axis; leaving 2 mm coronal structure out of each block. Teeth were then removed, light-body ZHERMACK Elite HD+(Zhermack S.p.A., Via Bovazecchino, 100 | 45,021 Badia Polesine (RO) ITALY) was injected all around the roots of specimens and inside their corresponding acrylic blocks and each specimen was repositioned into its specific block. Excess material was removed before complete setting. That step allowed the simulation of the periodontal ligament space in a thickness of 0.5 mm [Specimens held in acrylic resin blocks