골창 재위치를 이용한 측방접근 상악동골 이식술의 조직학적, 조직형태계측학적 평가

Abstract

Objectives: The maxillary sinus augmentation has become an important pre-prosthetic surgical procedure in the atrophic maxillary posterior edentulous ridge. Many researchs and clinical experiences focused on two most important subjects: bone replacement grafts and surgical approachs which are simpler and the least chance for complications. The aim of this study is to evaluate the histologic and histomorphometric effect of the bony window repositioning without barrier membranes.

Materials and Methods: A total of nine patients who had a residual bone height under the maxillary sinus lower than 5 mm and who don't have a systemic medical contraindications to implant surgery were included. After initial examination, cone-beam computerized tomography scan was obtained per patient to evaluate radiographic reference parameters: residual bone height, lateral window thickness and bucco-palatal sinus width. All the patients were treated with sinus floor augmentation via a lateral approach. Outfracture osteotomy for repositioning bone window was performed using piezoelectric device (Mectron®, Carasco, Italy). Membrane elevation curettes were used to raise the sinus membrane, and all the sinuses were grafted with allograft (Puros®; Zimmer, USA). After grafting, bone window harvested from lateral wall was replaced. After 6 months at the time of implant placement, clinical examinations to evaluate soft tissue invasion on lateral windows were performed. Bone core biopsies were harvested each of the maxillary augmentated sinus from the crest. For excluding residual bone from bone biopsies, point drill was firstly used at the residual bone height and then trephine bur was used with an inner diameter of 2 mm and depth of 8 mm. Sections of bone core biopsies were obtained and stained with hematoxylin and eosin. Histologic and histomorphometric analyses were performed to evaluate the proportion of newly formed bone, residual graft material and connective tissue.

Results: Clinically, in all the lateral walls, there was no soft tissue invasion sign. The gap between the repositioned bony window and the intact maxillary lateral wall was well healed by newly formed tissue. At the histologic examination, new bone formation was found in all biopsy samples. Histomorphometric examination showed that newly formed bone was 40.6 ± 14.3% of the total volume. Residual graft material was 4.8 ± 5.9%. The mean percentage of connective tissues was 54.6 ± 12.2%.

CONCLUSION: The results suggest that maxillary sinus augmentation with the use of replaceable bony window using piezoelectric device is a reasonable treatment choice without using barrier membrane. Further studies about implant survival rate with a long-term follow-up time after functional loading are needed for the confirmation of the stability of this procedure.