Immediate Subcrestal Morse-Taper Implant in a Fresh Extraction Socket, with Management of an Early Interdental Septal Complication Using Platelet-Rich Fibrin: A 56-Month Case Report

Background: Immediate implant placement in the anterior maxilla shortens treatment time, but has long been associated with marginal bone loss, most often reported for equicrestal, internal-hex systems. Laboratory studies of Morse taper connections report reduced abutment micromovement and, for some assemblies, reduced microbial leakage, which has been proposed to make deep subcrestal placement biologically acceptable. Methods: We report a 62-year-old healthy man with a vertical root fracture of the maxillary right central incisor, treated with flapless extraction and immediate placement of a 4.5 × 15 mm Morse taper implant, 2 mm subcrestal to the mid-buccal bony crest (insertion torque 45 N·cm; implant stability quotient 72), with freeze-dried bone allograft in the jump space and an immediate non-functional provisional restoration. Early healing was complicated by wound breakdown with a probeable defect at the distal interdental septum (probing depth 5 mm from the adjacent soft tissue margin to exposed bone at its base), interpreted clinically as suspected localized septal osteonecrosis (no biopsy or culture was obtained) and presenting in a manner resembling alveolar osteitis. This complication was managed conservatively with six weekly applications of platelet-rich fibrin, after which healing was uneventful. A definitive cement-retained porcelain-fused-to-zirconia crown on a zirconia–titanium abutment was delivered 5 months after implant placement. Results: The first radiographic bone-to-implant contact lay 1.5 mm (mesial) and 2.0 mm (distal) apical to the platform at 15 months, at the level of the first implant thread, and 2.0 mm on both aspects at 56 months. The total early bone change could not be quantified because no comparable baseline measurement exists. Between 15 and 56 months, the non-standardized periapical radiographs showed no evidence of progressive resorption (distal level unchanged; mesial 0.5 mm difference of uncertain significance). After resolution of the early complication, the peri-implant tissues remained clinically healthy, and the esthetic result, documented with an adapted, clinician-assessed application of the pink and white esthetic score, was stable (17/20 at 15 and 56 months); the patient, himself a dentist, reported being satisfied with the outcome. Conclusions: In this well-selected patient, immediate placement and non-functional provisionalization of a subcrestal Morse taper implant were followed by an early septal complication that resolved after conservative management including platelet-rich fibrin, and subsequently by clinically healthy peri-implant tissues and no radiographic evidence of progressive crestal resorption between 15 and 56 months. As an uncontrolled single case with several concurrent favorable factors, this report documents the clinical course of the complication and its management and cannot attribute the outcome to any individual treatment component.