Retrospective radiographic assessment of marginal bone level changes and peri-implant trabecular bone patterns around...

This study aimed to describe changes in marginal bone levels (MBL) and peri-implant trabecular radiomorphometric patterns during the osseointegration period in posterior mandibular implants healed with either healing abutments or cover screws.

This retrospective radiographic cohort study included 53 posterior mandibular implants in 36 patients, classified into the healing abutment group (n = 22) and the cover screw group (n = 31), based on the immediate postoperative panoramic radiographs. Digital panoramic radiographs obtained before implant placement (T0), immediately after implant placement (T1), and after a 3-month osseointegration period (T2) were analyzed. Marginal bone level (MBL) changes and radiomorphometric indices, including fractal dimension (FD), lacunarity, bone area fraction (BAF), and mean gray value (MGV), were calculated.

MBL values decreased significantly from T1 to T2 in both groups (p < 0.05). No statistically significant between-group difference in MBL change was detected at either the mesial or distal surface (p > 0.05). In the overall cohort, mean lacunarity decreased, whereas mean FD, BAF, and MGV increased. Group-based analyses showed significant longitudinal changes in all radiomorphometric parameters in the cover screw group, while only FD changed significantly in the healing abutment group (p < 0.05). For the overall mean radiomorphometric values, no statistically significant between-group differences were detected at T2 (p > 0.05).

Posterior mandibular implants showed MBL reductions and radiomorphometric changes during the 3-month osseointegration period. MBL changes did not differ significantly between groups, while radiomorphometric trajectories differed descriptively. These findings provide descriptive radiographic information on early peri-implant bone changes and should be interpreted within the limitations of the retrospective cohort design.