A dental implant is provided that has a proximal-most part, a lateral external surface, and a distal implant portion that extends from a distal implant end along up to 50% of a longitudinal length of the implant. The implant is shaped so as to define a lumen therethrough (a) having at least one distal opening through a distal external surface of the distal implant portion, (b) having a lateral opening through the lateral external surface, and (c) not open to a proximal external surface of the implant within 2 mm of the proximal-most part of the implant. Other embodiments are also described.