Dental Implants: Adjacent Tooth Proximity and Contact

During the osteotomy and placement of dental implants, anatomical positions of adjacent natural teeth to a dental implant site may be very close or in actual contact. This can be due to anatomy, the size of the implant site, a misguided osteotomy, drifting, or migration of the adjacent tooth. The implant surgeon needs to be aware of the position of adjacent teeth to avoid root damage from the implant drill or the implant itself. The dimension of 1.5-mm space has been discussed, but it is an arbitrary speculative dimension. There is no agreed-upon "safe" proximity to adjacent tooth roots. Theoretically, a large displacement size of an implant may inhibit bone remodeling and cause bone loss if placed close to an adjacent tooth. A small diameter or mini-implant may not significantly affect bone remodeling when placed in close proximity or even in contact with an adjacent tooth root. Many factors dictate "safe" proximity, including the implant diameter, tooth root displacement, periodontal ligament, bone quality, and patient physiologic factors, including diseases and medications. The degree of root contact by an implant or implant drill may be graded by the contact depth. Grade 1 is contact with periodontal ligament, Grade 2 is contact with periodontal ligament and cementum, Grade 3 is contact with periodontal ligament, cementum, and dentin penetration, and Grade 4 is contact with periodontal ligament, cementum, root dentin, and pulpal penetration. This discussion highlights the need for further research on dental implant proximity and contact with adjacent teeth.