Implant-Guided Volumetric Analysis of Edentulous Maxillary Bone With Cone-Beam Computerized Tomography Scan. Maxillary Sinus Pneumatization Classification

摘要

The primary goal of this anatomic study was to measure the average bone volume of thenedentulous maxilla with a cone-beam computerized tomography (CBCT) scan and tondetermine its suitability for implant treatment without additional bone grafting. Thensecondary goal of the study was to estimate the degree of sinus pneumatization (SP) innreviewed CBCT scans, assess the sinus-to-maxillary bone interrelationship in edentulism, andnattempt to classify maxillary sinuses based on the degree of their pneumatization. Thisnretrospective radiographic quantitative study consisted of the analysis of CBCT scans of 30nrandomly selected maxillary edentulous patients who presented in 2008–2010 to thenUniversity of the Pacific, Arthur A. Dugoni School of Dentistry, for evaluation and treatmentnof their edentulism. A volume of edentulous maxillary bone mesial to the maxillary sinusesn(intersinal region) that can be used for a full-arch implant treatment was evaluated based onnspecifically selected and clinically relevant measurement criteria. There were 30 CBCT scansnof maxillary edentulous patients reviewed (9 men, 21 women) with a mean age of 67.3 yearsn(range, 41 to 92 years). The total mean maxillary bone volume (MMBV) suitable fornimplantation was 4 408.1 mm3 and ranged from 1489.7 to 7263.1 mm3. The MMBV in thenstudy was higher than an assumed or hypothetical bone volume minimally suitable for 4-nimplant treatment as proposed by the authors for comparative purposes (3500 mm3). Thendegree of SP as seen on a CBCT scan (60 sinuses analyzed on panoramic images of 30 CBCTnscans) had the following results in the study: SP0 (clear: not interfering with implantntreatment in cases of high/small sinus), 2 sinuses or 3.3%; SP1 (mild sinus enlargement), 29n1 Private practice, San Francisco, Calif.n2 Department of Oral and Maxillofacial Surgery, University of the Pacific, Arthur A. Dugoni School of Dentistry,nSan Francisco, Calif.n3 University of California San Francisco, School of Dentistry, San Francisco, Calif.n4 General dentistry private practice, San Francisco, Calif.nCorresponding author, e-mail: tolstunov@yahoo.comnDOI: 10.1563/AAID-JOI-D-11-00212nJournal of Oral Implantology 377nCLINICALnsinuses or 48.3%; SP2 (moderate SP), 16 sinuses or 26.7%; SP3 (severe SP), 9 sinuses or 15.0%;nand SP4 (extreme), 4 sinuses or 6.7%. Most analyzed maxillary sinuses (47 of 60, or 78.3%)nwere in the clear, mild, or moderate categories of SP (SP0, SP1, and SP2), which have ansufficient amount of maxillary bone beneath the maxillary sinuses to allow a full-arch implantntreatment. An inverse correlation between SP and MMBV was observed. Although manynother clinical criteria are important (bone quality, alveolar crest anatomy, etc), the results ofnthis CBCT radiographic study indicate that in many maxillary edentulous cases, the existingnbone quantity (volume) can be sufficient for a full-arch maxillary implant treatment with atnleast 4 implants without the additional trauma or expense of bone grafts and sinus lifts. Anvariety of implant treatment options can be proposed based on maxillary bone availabilitynand bone-to-sinus interrelationship. It appears that with age and edentulism, the amount ofnavailable maxillary bone is steadily decreasing.