A dental implant drill-guide system comprising: a plurality of two-part orthodontic screws , a coronal part of each two-part orthodontic screw having a screw-thread which is receivable within an apical part of the two-part orthodontic screw ; and a dental implant drill-guide , the dental implant drill-guide having a guide body which is complementarily-shaped to an edentulous maxillary or mandibular arch of a patient, a plurality of first apertures (34; 56) through the guide body each having an orthodontic screw-seat associated therewith which is engagable with the apical part of one said two-part orthodontic screw , and at least one second aperture (36; 58) which is oriented and sized to form a drill-guide through which a dental drill for drilling a dental-implant cavity in the edentulous maxillary or mandibular arch can pass; and wherein the apical part of the two-part orthodontic screws includes an apical flange and a collar extending upwardly from the apical flange , each two-part orthodontic screw-seat being formed as a flat surface on a base of the guide body (34; 54) at a respective first aperture , the coronal part of the two-part orthodontic screws abuttably engaging with a top of said first aperture (34; 54) to apply a clamping force onto the dental implant drill-guide when threaded into the apical part of the two-part orthodontic screws . a plurality of two-part orthodontic screws , a coronal part of each two-part orthodontic screw having a screw-thread which is receivable within an apical part of the two-part orthodontic screw ; and a dental implant drill-guide , the dental implant drill-guide having a guide body which is complementarily-shaped to an edentulous maxillary or mandibular arch of a patient, a plurality of first apertures (34; 56) through the guide body each having an orthodontic screw-seat associated therewith which is engagable with the apical part of one said two-part orthodontic screw , and at least one second aperture (36; 58) which is oriented and sized to form a drill-guide through which a dental drill for drilling a dental-implant cavity in the edentulous maxillary or mandibular arch can pass; and a guide body which is complementarily-shaped to an edentulous maxillary or mandibular arch of a patient, a plurality of first apertures (34; 56) through the guide body each having an orthodontic screw-seat associated therewith which is engagable with the apical part of one said two-part orthodontic screw , and at least one second aperture (36; 58) which is oriented and sized to form a drill-guide through which a dental drill for drilling a dental-implant cavity in the edentulous maxillary or mandibular arch can pass; and wherein the apical part of the two-part orthodontic screws includes an apical flange and a collar extending upwardly from the apical flange , each two-part orthodontic screw-seat being formed as a flat surface on a base of the guide body (34; 54) at a respective first aperture , the coronal part of the two-part orthodontic screws abuttably engaging with a top of said first aperture (34; 54) to apply a clamping force onto the dental implant drill-guide when threaded into the apical part of the two-part orthodontic screws . <EOS>