Line 5: bone resorption (mesial and distal measurements) around each implant; line 4: time of loading goes from 54 months (implants numbers 1 and 2) up to 22 months (implants numbers 10 and 11). Lines 1 and 2: implants are located in intermediate (Int., number 3-4-7-8), mesial (Mes., number 10), and distal (Dis., number 1-2-5-6-9) positions; one implant is a single-unit implant (S, number 11). Line 3: element(s) with which the extrashort implants are directly connected: implant (I), natural tooth (T), or both (I + T); in those cases, the teeth are always located distally. Line 6: C/I ratio: crown-to-implant ratio; measurement concerns the anatomic ratio (fulcrum located at the implant shoulder). Line 7: pocket depth: mean pocket depths around the ESI (test group, in bold) or around the contralateral teeth or implants (control group, in italic).