Cone Beam Computed Tomography evaluation of palatal bone thickness for miniscrew placement in Down's syndrome.

OBJECTIVES: To quantify palatal bone thickness (PBT) in Down's syndrome (DS) patients in order to identify the best areas for miniscrew placement.

DESIGN: The study group was formed of 40 DS patients (25 male and 15 female) with a mean age of 18.4±6.3 years (range, 9-40 years). A control group of 40 non-syndromic age- and sex-matched individuals was selected. Maxillary CBCT images were available for all participants. Coronal sections of the hard palate were selected at 4, 8, 16 and 24mm posterior to the distal wall of the incisive foramen. PBT measurements were performed at 20 selected points on these coronal sections at the midline and at 3 and 6mm to right and left of the suture.

RESULTS: Overall, PBT was similar in DS and controls and it was not affected by age or sex. In both groups PBT decreased progressively with increasing distance from the posterior wall of the nasopalatine foramen in an anteroposterior direction, except along the median palatal suture. PBT along the suture was lower in DS than in controls in all the paracoronal image planes (P=0.02, 0.007, 0.01 and 0.02 at 4mm, 8mm, 16mm and 24mm, respectively, from the incisive foramen). PBT at the most anterior paramedian locations was also lower in DS than in controls (P=0.02 and 0.03, respectively, 3mm to the right and left of midline).

CONCLUSIONS: In DS individuals, the most suitable area for miniscrew placement in terms of bone volume is the median palatal suture, irrespective of age or sex, as occurs in the general population, followed by the paramedian sites closest to the incisive foramen.