Which region of the median palate is a suitable location of temporary orthodontic anchorage devices? A histomorphometric study on human cadavers aged 15-20 years.

Introduction: Endosseus implants can provide a reliable anchorage during orthodontic treatment. The midpalatal structures around the sutura palatina mediana (SPM) are of special interest due to increasing placement of orthodontic implants in this area. Knowledge about the osseous conditions at this site is necessary to predict the expected degree of implant osseointegration.

Methods: The upper jaws of 10 human cadavers, aged 15-20 years, were decalcified, and cross-sectional specimens were obtained from four anterior-to-posterior palatal regions for histomorphometric analysis. The analyses focused on the amount of bone and the width of the SPM to determine the anatomical requirements for reliable insertion of palatal implants.

Results: Bone density [bone-volume (BV)/ tissue-volume (TV)] in all measured areas was 40-60%. The maximum density was measured at the level of the first premolars (54.9+/-5.9%) and the least values (44.2+/-9.6%) were measured at the level of the interconnecting line of the canines. The mean width of the SPM varies from 1.2 to 0.3 mm in different sections of the palate. In the median sagittal plane, the mean values of bone height to nasal cavity reached >5 mm as far as the level distal of the second premolars. Bone height 2 mm paramedian to the SPM decreased consistently from anterior (4.3+/-0.9 mm) to posterior (2.5+/-0.8 mm).

Conclusions: Our results indicate that the amount and quality of bone along the anterior palatal midline in 15-to-20-year olds is sufficient for orthodontic implantation. Even implantation posterior to the recommended first premolar level, at which orthodontic implants are most often placed, may be suitable. There are some limitations, however, due to small number of samples and variations of anatomical structures.