Thickness of labial alveolar bone overlying healthy maxillary and mandibular anterior teeth.

AIM: This study aimed to measure the thickness of labial bone overlying maxillary and mandibular anterior teeth and the distance between cementoenamel junction and bone crest in a Persian population. MATERIALS & METHODS: Two calibrated examiners evaluated tomographic data of 152 maxillary and 200 mandibular anterior teeth. Labial bone width was assessed at levels 1.0 to 5.0 mm apical to bone crest. Moreover, the distance between cementoenamel junction and bone crest was measured for both maxillary and mandibular teeth and its potential effect on the amount of labial bone thickness was assessed. RESULTS: One hundred-twenty nine maxillary central incisors, 77 lateral incisors, 70 canines, 105 mandibular central incisors, 103 lateral incisors and 81 canines were included for measurements. In maxilla, width of bone averaged 1.08mm, 1.11mm, and 1.3mm for central incisors, lateral incisors, and canines, respectively. Corresponding numbers for mandibular central incisors, lateral incisors, and canines were 0.74mm, 0.66mm and 0.40mm. High variation of cementoenamel junction to bone crest distance (range 0.5 to 5.15 mm) was detected. The mean amount of labial bone width was not statistically different in patients with different distances between cementoenamel junction and bone crest; except for mandibular lateral incisors. CONCLUSION: The mean thickness of the labial alveolar bone overlying maxillary anterior teeth was found to be between 1 to 1.2 mm and between 0.5 to 0.8 mm for mandibular anterior teeth at the first 5 mm from bone crest in a Persian population.

Healing of extraction sockets and augmented alveolar defects following 1-year treatment with bisphosphonate.

To assess the effect of bisphosphonates on healing of extraction sockets and augmented alveolar defects, 12 adult female mongrel dogs were assigned to 2 experimental groups and a control group. The experimental groups received oral alendronate (ALN, 3.5 mg/kg/wk) or IV pamidronate (PAM, 1 mg/kg/wk) for 12 months. Animals were randomly tested for serum C-terminal telopeptide of collagen I (CTx). The right first and second premolars were extracted. After 8 weeks, extraction sites were evaluated for healing. Subsequently, 3-wall defects were created in ridges and filled with human mineralized cortical particulate bone. Two months post-augmentation, animals were sacrificed and mandibles were collected for cone-beam computed tomography (CBCT) and histomorphometric appraisal. The obtained data were compared using 1-way ANOVA test. CTx test results in both experimental groups were comparable (<10 pg/mL) but lower than that of the control group (minimum 159.2 pg/mL). Two months post-extraction, bone sequestra were noticed in extraction sites in BP-treated groups, involving the entire alveolar bone in the PAM group and the upper rim of the alveoli in the ALN group. Histologically, bone sequestra from the PAM group demonstrated empty osteocyte lacunae, while in the ALN group areas of necrotic bone along with evidence of active bone remodeling was distinguished. Eight weeks post-augmentation, the experimental groups showed no evidence of bone formation in the augmented area, while bone formation ratio was measured to be 18.32% in the control group. The mean amount of pixel intensity calculated from the CBCT images of the ALN, PAM, and control group was 113.69 ± 11.04, 124.94 ± 4.72, and 113.69 ± 6.63, respectively. Pixel intensity in PAM-treated group was significantly higher than both other groups. This study demonstrated that 1-year treatment with ALN/PAM was associated with impairment of post-extraction and post-augmentation bone healing in dogs.

Accuracy of linear measurement using cone-beam computed tomography at different reconstruction angles.

PURPOSE: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., 0°), +10°, +12°, -12°, and -10° with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. RESULTS: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of -12°, -0.66 to -0.11 at -10°, -0.51 to +0.19 at 0°, -0.64 to +0.08 at +10°, and -0.64 to +0.1 at +12°. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. CONCLUSION: Changing the slice orientation in the range of -12° to +12° reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.