Histological and Histomorphometric Assessment With Inflammatory Profile Analysis of Bone Tissue After Horizontal Ridge Augmentation Using Customized Porous Zirconia Shell

Horizontal bone loss in the posterior mandible often prevents dental implant placement. The Khoury technique uses thin autogenous cortical bone plates to rebuild the ridge, but harvesting these plates causes donor-site morbidity, is technically demanding, and is limited by available bone. Zirconia is biocompatible, mechanically strong and osteoconductive, and has shown low inflammatory response. However, it has not been studied as a shell replacing autogenous bone plates.

In this single-arm study, 10 adults with Seibert Class I defects in the posterior mandible will first receive non-surgical periodontal therapy. Compliance will be checked after 1 month. A zirconia shell with 1.5 mm pores will be digitally designed from each patient's CBCT scan, milled on a 5-axis machine, then cleaned and sterilized.

Under local anesthesia, buccal and lingual full-thickness flaps will be raised and the recipient bone decorticated. Autogenous bone chips will be harvested from the mandibular body with a bone chip maker and mixed 1:1 with xenograft. The shell will be fixed over the graft with 3-4 buccal screws. The flaps will be advanced and closed with a double-layer suture.

After 6 months, the shell will be removed, a core biopsy will be taken, and an implant will be placed. The biopsies will be fixed in 10% formalin and analyzed histologically, histomorphometrically and for tissue inflammatory response.

Inclusion criteria

• Adults older than 21 years
• Horizontal bone defect (Seibert Class I) in the posterior mandible
• Enough inter-arch space for an implant-supported prosthesis
• Motivated to receive the treatment
• Good oral hygiene

Exclusion criteria

• Systemic conditions that could interfere with healing
• Pregnancy
• Smoking
• Poor oral hygiene