prezentacja

The primary treatment for middle-face tumors is resection with a margin of healthy tissue.

Surgical procedures in the hard and soft palate area lead to tissue defects, which can be closed immediately with surgical reconstruction or prosthetic restorations.

Immediate obturator plates protect the surgical site, separate the oral cavity from the nasal cavity, and restore speech, breathing, and nutrition functions.

They also support soft tissues, and as a result, improve facial aesthetics and the patient's well-being.

The study aimed to assess the accuracy of digital design according to the developed technique and fabrication of immediate postoperative plates using 3D printing technology in patients with planned resection of palatal tissues due to cancer.

10 patients aged 27 to 81 were qualified for the study, 5 women and 5 men.

The study used an intraoral and laboratory scanner, Blue Sky, Meshmixer, and Free CAD virtual design programs, resins for printing denture plates and models, a printer and a lamp for the final plates polymerization, and a flexible material for relining.

Intraoral scans of the maxillary foundation were performed in 3 patients with planned soft tissue resection, 3 patients before partial maxillary resection and 4 patients before total maxillary resection.

In the Blue Sky Plan software, intraoral scans were superimposed on models obtained from computed tomography scans, using the patient's teeth or mucosal level as a reference points.

Intraoral scans on the maxilla models were prepared according to the planned extent of tissue resection.

Then, plates were designed and print-ready files were prepared.

In the case of plates with an extended obturating parts, to reduce the weight of the restoration, the obturators were hollowed out in the Meshmixer program.

Additionally, 2 holes were designed to reduce the pressure inside the empty space during printing and to wash out the unpolymerised resin from inside the obturator.

Obturator plates were printed.

For dentate patients models were also printed to plan the position of the clasps.

Their instalation and the closure of the holes in the obturator were made using the same resin as used for printing.

The restorations were then processed in the dental laboratory using tools and materials for acrylic dentures.

Obturator plates were placed on the foundation immediately after the tissue resection.

From those prepared, two plates were finally not used.

In one case of total maxillary resection, it was decided to surgical reconstruct the defect.

In the other, the increased extent of resection was needed due to cancer progression- from partial one maxilla resection to subtotal resection of both maxillas.

About 2 weeks after resection procedure, the restorations were corrected, relined, and scanned in a laboratory scanner.

In the Blue Sky Plan program, plate designs were combined with scans of the relined plates.

Then the obturating parts were cut off and the material that penetrated the recesses of the resection cavity was removed.

Then the volume of the obturating part before and after relining or correction was measured in the Free CAD software.

and the percentage accuracy of the designed plates was calculated.

The average accuracy for plates before planned total maxillary resection was 93.76 %, before soft tissue resection 92.56 % and before partial maxillary resection 81.97 %

The average accuracy of all plates was 89.43 %

Based on the study, the following conclusions were drawn.

The developed technique may be an alternative method for immediate restorations as the accuracy achieved by the plates prepared for the surgical procedures was high.

Close cooperation between the prosthodontist and the maxillofacial surgeon performing the resection procedure is important.

Further clinical studies of the presented method are necessary.