Comparative long-term augmentation stability of L- and I-shaped guided bone regeneration techniques for maxillary anterior region

Background: This study evaluated the efficacy of L- and I-shaped collagenated block bone substitutes (BBS) compared with particulate bone substitutes (PBS) in guided bone regeneration (GBR) of maxillary anterior peri-implant dehiscence defects. It focused on radiographic, profilometric, esthetic, and patient-reported outcomes over a 4-year follow-up period. Methods: Fifty-one peri-implant defects were treated with L-shaped (GBR-L, n = 16), I-shaped (GBR-I, n = 14), and PBS (GBR-P, n = 21) grafts. Hard and soft tissue profiles based on cone beam computed tomography (CBCT) and oral scans, esthetic outcomes based on pink and white esthetic scores (WES) and Mucosal Scar Index (MSI), and patient-reported measures based on the Oral Health Impact Profile-14 (OHIP-14) were evaluated. Statistical analyses (chi-squared, Mann–Whitney U, Kruskal–Wallis tests) compared groups at baseline, implant surgery, re-entry, and 4-year follow-up. Results: At early follow-up, significant differences in hard and soft tissue profiles were observed at the implant shoulder and 45° positive angles between the GBR-L, GBR-I, and GBR-P groups (p < 0.05). However, these differences diminished over time, and no statistically significant differences remained at the 4-year follow-up. Similarly, esthetic and patient-reported outcomes showed no significant differences among the groups. Conclusions: Within the limitations of this study, the use of L- or I-shaped collagenated BBS in GBR showed no significant radiographic, profilometric, esthetic, or patient-related differences compared to GBR with PBS over 4 years of long-term follow-up. In particular, the significant volumetric shrinkage observed with collagenated BBS may affect the long-term stability of the GBR procedure. Plain language summary: This study focused on improving the success of dental implants in the maxillary anterior region, a challenging region due to esthetic and structural requirements. The researchers compared three methods of guided bone regeneration (GBR) using different types of bone graft substitutes: L-shaped, I-shaped, and particulate materials. They monitored bone and gum stability, appearance, and patient satisfaction over 4 years. Initial results showed slight differences in bone and gum support between the methods, but these differences disappeared by the end of the study. All approaches produced similar results in terms of long-term stability, esthetic appearance, and patient satisfaction. The results provide guidance to dentists in their choice of GBR techniques for dental implants, emphasizing that different methods can achieve comparable long-term success when used carefully.