A root implant (1) includes a body portion (11), a drilling portion (12) formed thereon, a positioning hole (13) formed opposite to the drilling portion (12), and a threaded portion (14) spiraled on the body portion (11). The body portion (11) and the coarse thread (141) have respective first openings (111) and second openings (1411) processed by a high-energy optothermal method to be spaced apart by equal distance. The first openings (111) and the second openings (1411) accommodate accretions grown from the alveolar bone when the root implant (1) interfaces with the alveolar bone (2). Between the first openings (111) and between the second openings (1411) are respectively defined first joint sections (112) and second joint sections (1412) whereby the accretions can climb and link together for providing a tight combination between the root implant (1) and the alveolar bone, preventing the loosening problem caused by external forces and increasing a positioning effect of the root implant (1).
