The Study Of Palatal Bone Thickness And Cortical Bone Density For Mini-Implant Placement In Adults By Cone Beam Computed Tomography

Objective To evaluate the bone thickness and cortical bone densities of the palatal area using cone beam computed tomography (CBCT).Methods CBCT scans of 103 adults (49 men, 54 women, 20 to 40 years old) were selected and the measurements of palatal bone thickness were made at 28 sites. CBCT scans of 107 adults (51 men, 56 women, 20 to 40 years old) were selected and palatal cortical bone density was measured in Hounsfield units (HU) at 28 sites. Repeated measures analysis of variance was used to test the intragroup differences of bone thickness and cortical bone density. The relationship between gender were analyzed by t-test, and correlations between palatal bone thickness and cortical bone density were analyzed by using Pearson correlation coefficients.Results1. Bone thickness:The maximum value of palatal bone thickness was (11.90 ± 2.73) mm, and the minimum value was (1.53 ± 0.98) mm. Significant differences were seen between the male and female groups in 21 sites (P<0.05). The thickness of palatal bone tended to decrease posteriorly, except the midpalatal suture. The safe zones of the palate for mini-implant insertion were located at the midpalatal suture and the anterior region of the paramedian palate.2. Cortical bone density:The maximum value of palatal cortical bone densities was (976.24 ± 138.66) HU, and the minimum value was (460.45 ± 183.33) HU. There were significant differences between the male and female groups in 20 sites (P<0.05). Palatal cortical bone densities showed a tendency to decrease posteriorly (P=0.000). The cortical bone densities at locations that 3 mm from the midpalatal suture to lateral side were greater than at midpalatal suture in the anterior palate (P<0.05).3. There were no significant correlations between palatal bone thickness and cortical bone density (P>0.05).Conclusion The distribution of palatal bone thickness and cortical bone densities in adults are obtained by CBCT. These data might provide valuable information for selecting sites to place mini-implants in the palate.