(74) Clinical Evaluation of Patient-Specific 3D-Printed PCL/β-TCP Scaffolds for Alveolar Ridge Augmentation: A Pilot Case Report

Abstract: The rehabilitation of atrophic alveolar ridges in post-traumatic and long-standing edentulous sites remains a significant challenge, particularly in elderly patients. Vertical and horizontal bone augmentation techniques include autologous bone block grafting, titanium scaffolds, and sinus lift procedures, while alternative solutions such as zygomatic and subperiosteal implants are also utilized. Recently, the application of customized three-dimensional (3D) printed bioceramic and polymer scaffolds for guided bone regeneration (GBR) has gained attention due to their bioresorbability and elimination of the need for secondary removal. This pilot study evaluates the clinical outcomes of customized 3D-printed polycaprolactone/β-tricalcium phosphate (PCL/β-TCP) scaffolds in vertical and horizontal bone defects in two patients.

A 37-year-old male presented with a severe atrophic defect in the upper right maxilla at the site of previously extracted teeth (#4 and #5), measuring 5.3 mm in height and 3.9 mm in width from the crestal base of the maxillary sinus. Similarly, a 59-year-old female exhibited a comparable defect in the edentulous region of teeth #3 and #4, with a ridge height of 1.8 mm and a width of 2.4 mm from the sinus base. Both cases demonstrated significant alveolar ridge resorption following traumatic extractions, resulting in knife-edge ridges unsuitable for implant placement. Patient-specific scaffolds (ASBONE, Omid Afarinan Baft Ayandeh) were designed using cone-beam computed tomography (CBCT) scans and advanced 3D modeling software (3-Matic and Mimics, Materialise). The scaffolds, featuring a 0.6 mm layer thickness and 30% porosity, were positioned with a 1.5 mm safety margin from adjacent teeth, targeting a horizontal bone increase of 6 mm and vertical gains of 3 mm and 2.2 mm for the respective cases. Cortical-cancellous bone powder (150–1000 µm, Kish Tissue Regeneration Corp.) was used in conjunction with the scaffolds, which were fixated with one screw in the buccal plate, respectively. Platelet-rich fibrin (PRF) was incorporated to support soft tissue healing, and primary closure was achieved.

Postoperative follow-up was conducted at 1 week, 2 weeks, 1 month, and 3 months. Both patients experienced moderate to severe inflammation and swelling during the first week without significant pain. Poor oral hygiene was noted, necessitating consistent reinforcement of hygiene protocols. From the 1st to the 3rd month, progressive scaffold exposure, crestal ridge dehiscence, and flap release were observed. Secondary closure and irrigation were performed; however, relapse of exposure and increased probing depths (7–8 mm) indicated a lack of soft-tissue integration with the scaffold. Ultimately, scaffold explantation was necessary due to the absence of bone integration.

In conclusion, despite initial healing, progressive scaffold exposure and failure of tissue integration necessitated removal. The compromised soft-tissue environment due to prolonged resorption posed a significant challenge to achieving tension-free primary closure, leading to dehiscence and subsequent scaffold exposure. Additionally, poor oral hygiene may have further contributed to delayed healing and soft-tissue instability. These findings underscore the critical role of both bone and soft-tissue management in guided bone regeneration. Future research should explore modifications in scaffold design, fixation techniques, and biomaterial composition to enhance stability and osseointegration, ensuring long-term success in alveolar ridge augmentation.

1. Park JY, Jeon SH, Lee JY, Park JM, Cha JK. Vertical and horizontal ridge augmentation using customized three-dimensionally printed polycaprolactone mesh in atrophic posterior maxillae: a case report. J Oral Implantol. 2023 Feb 16. doi: 10.1563/aaid-joi-D-22-00007. Epub ahead of print. PMID: 36796059.

2. Clinical application of 3D-printed patient-specific polycaprolactone/beta tricalcium phosphate scaffold for complex zygomatico-maxillary defects. Polymers. 2022;14(4):740.
Figure 1. Second Patient-specific Scaffold Design Buccal View Figure 2. First Patient-specific Scaffold Design Palatal and Coronal View Figure 3. Graft Site after Fixation of Scaffold ( Second Patient)