Long-Term Bone Dimensional Changes Following Flapless Immediate Implant Placement

Long-Term Bone Dimensional Changes Following Flapless Immediate Implant Placement With or Without Bone Grafting: A 5 Years Follow up of a Randomized Clinical Trial

Nowadays, achieving long-term hard tissue stability is the definitive goal of a successful immediate implant placement and has become the optimal challenge for clinicians over the past few decades. It is wellestablished that the dimensional changes and remodeling of the alveolar ridge represent a physiologic sequela of tooth extraction and is inevitable especially the labial bone wall. This creates an unfavorable labio-palatal discrepancy and produces the "fixture-socket gap" around the coronal portion of the implant, known as the labial gap especially in sockets with thin bone.Although this gap has the potential to repair spontaneously in some cases, still previous studies reported that this gap cannot be completely filled without using a regenerative material. It has been claimed that buccal/labial gap augmentation contributes to the final esthetic success of the dental implant, where the regenerative material acts as a scaffold to maintain the blood clot, promote bone formation, compensate for the postextraction socket remodeling and maintain the buccal bone thickness and thereby preventing the buccal contour collapse. Nevertheless, this would add an additional cost and prolong the surgical procedure. Meanwhile, there is a controversy in the existing literature regarding the actual benefit of using bone grafts in the buccal gap. Previous systematic reviews concluded that there is not sufficient evidence to prove that immediate implant placement with grafting the labial gap, would comprise an additional benefit in preventing alveolar ridge reduction and contour collapse. Furthermore, previous controlled clinical trials reported that evidence for this additional treatment is still unclear.

Patients who completed the initial trial and received a single immediate implant in a fresh extraction socket would be invited for reassessment at 5 years after implant placement. The intervention group would comprise patients treated with flapless immediate implant placement combined with grafting of the peri-implant gap using the same bone-substitute material and protocol applied in the original study, while the control group would comprise patients treated with flapless immediate implant placement without bone grafting. The primary outcome would be the change in peri-implant marginal bone level and three-dimensional alveolar ridge dimensions, assessed by standardized periapical radiographs and, where ethically and clinically justified, limited-field cone-beam computed tomography, compared with baseline and the earlier follow-up measurements. Secondary outcomes would include implant survival and success, peri-implant probing depth, bleeding on probing, plaque accumulation, mucosal recession, width of keratinized mucosa, facial soft-tissue profile, biological complications, prosthetic complications, patient satisfaction, and esthetic outcomes. Assessments should be performed by calibrated, blinded examiners using standardized imaging and clinical protocols. The study would analyze all eligible participants according to their original randomized allocation, report reasons for loss to follow-up, and compare the long-term dimensional stability and clinical performance of grafted versus nongrafted sites. The principal hypothesis would be that bone grafting may reduce long-term horizontal ridge resorption and improve preservation of the facial contour without adversely affecting implant survival or peri-implant health over the 5-year observation period.

Inclusion Criteria:

• Adult (>20 years) with nonrestorable maxillary teeth in the esthetic zone, thick gingival phenotype, intact but thin labial plate of bone extending 7 mm (≤1 mm) and intact palatal bone extending at least 6 mm apically, sufficient apical bone to attain implant primary stability (a minimum of 35 N cm insertion torque) and labio-palatal socket dimension measured from the CBCT axial cut at mid-crestal part ≥5 mm.

Exclusion Criteria:

• Smokers, pregnant women, patients with systemic disease, patients with parafunctional habits such as bruxism or clenching, infected socket, periapical pathosis and history of radiotherapy or chemotherapy within the past 2 years.