Dental implantation: ultrasound transmission velocity to evaluate critical bone quality--an animal model.
OBJECTIVE
In dental implantology, preoperative evaluation of bone quality is an important aspect for the long-term success of the treatment. The insertion of implants into regions with a great portion of poorly mineralised cancellous bone, in particular, increases the risk of subsequent implant failure. The measurement of Ultrasound Transmission Velocity (UTV) proved to be a non-invasive and valid method for the assessment of mechanical properties of bone. The aim of this study was to correlate conventional histomorphometric bone properties with UTV-values from mandibular and iliac crest bone specimens in an animal model.


METHODS
12 native (no sample preparation) porcine specimens from mandibular bone and 14 from iliac crest bone, respectively, were studied both by UTV measurement and by conventional histomorphometry. UTV-values were measured bicortically by three different investigators four times at each site. Bone samples from identical sites were obtained and ground down to a thickness of approx. 50 microm. Transmission light microscopy was used to assess the overall percentage of mineralised bone. Mineral bone density less than 40% was defined as "critical".


RESULTS
The median bone density was 43 % for mandibular bone and 23% for iliac crest bone, respectively. The median UTV values of the mandible (1756 m/sec) were significantly higher than those of the iliac crest specimens (1613 m/sec). Intra-individual correlation testing illustrates a positive, statistically significant correlation between presurgical UTV measurement and the grade of mineralisation (r=0.54). ROC analysis defined a UTV breakpoint of 1767 m/sec to identify critical bone with a sensitivity of 75%.


CONCLUSIONS
In this ex-vivo model, UTV measurements have proven to be a reliable method for identifying critical bone quality prior to implantation.
Al-Nawas
B
B
Department of Oral and Maxillofacial Surgery, University Hospital Mainz, Mainz, Germany. al-nawas@mkg.klinik.uni-mainz.de
Klein
M O
MO
Götz
H
H
Vaterod
J
J
Duschner
H
H
Grötz
K A
KA
Kann
P H
PH
D000818:Animals; D002113:Calcification, Physiologic; D015921:Dental Implants; D007082:Ileum / Q000000981:diagnostic imaging*; D008334:Mandible / Q000166:cytology / Q000000981:diagnostic imaging*; D023421:Models, Animal; D013552:Swine; D016896:Treatment Outcome; D014463:Ultrasonography