Three-dimensional evaluation of interproximal contacts of permanent dentition: a cone beam computed tomography study.

PURPOSE: To assess the various patterns of the inter-proximal contact areas of the permanent dentition using the available cone beam computed tomography (CBCT) images. METHODS: A retrospective cross-sectional study was performed on existing CBCT images from a University hospital and teaching department. Three thousand two hundred and fifty inter-proximal contacts were assessed from 125 existing CBCT scans of patients (age range: 14 years 3 months-29 years 9 months) who had matched the eligibility criteria. The types of inter-proximal contacts of the permanent dentition were scored at occlusal, middle, and cervical thirds, according to the OXIS inter-proximal contacts classification. Chi-square test was used to assess the contacts and gender/arches. RESULTS: The most prevalent contact was type I for the posterior teeth contacts, and types S1 and S2 for the anterior teeth contacts. Statistical significance was not observed between the contacts on the left and right sides (P > 0.05), while statistical significance was observed between the inter-proximal contacts of the maxilla and mandible (P < 0.05). CONCLUSION: The CBCT-based three-dimensional assessment of the inter-proximal contact areas of the permanent dentition is representative of the OXIS classification. The occlusal level contact was predominantly representative of the overall type of the contact.

Evaluation of the accuracy of linear measurements on spiral computed tomography-derived three-dimensional images and its comparison with digital cephalometric radiography.

OBJECTIVES: The aim of the study was to evaluate the accuracy of linear measurements obtained from reconstructed spiral CT images of human dry skulls in three planes by comparing them with direct skull measurements, and then to compare these with measurements made on photostimulable phosphor cephalograms. METHODS: Using a Siemens Somatom Sensation spiral CT scanner (Munich, Germany), CT images of six human dry skulls were imported into imaging software (Mimics 11.02 Materialise, Leuven, Belgium) and the measurements made were compared to the direct measurements made using a digital calliper (500-171, CD-6C, Mitutoyo, Kawasaki, Japan). The measurements were also compared to those made on frontal and lateral cephalograms taken using a digital cephalostat (Planmeca Oy, Helsinki, Finland). The mean of the 15 linear measurements obtained were compared using the paired Student's t-test. RESULTS: CT measurements did not show a significant difference from the direct skull measurements (P < 0.05) in all three planes except for two midsagittal measurements in the anteroposterior plane. Cephalometric measurements were comparable to direct skull measurements for midsagittal measurements in the anteroposterior plane, but showed a significant difference when bilateral measurements were considered. Cephalometric measurements also showed a significant difference in the transverse plane from direct measurements and CT measurements; however, they did not display a significant difference between direct skull measurements and CT measurements for most parameters in the vertical plane. CONCLUSION: Linear measurements on the spiral CT were comparable to anatomical measurements and were more reliable than cephalometric measurements. Cephalometric measurements were acceptable for midsagittal measurements in the anteroposterior plane, but showed a significant variation from anatomical and CT measurements in most other parameters.

Controlled clinical assessment of astemizole in the treatment of chronic idiopathic urticaria and angioedema.

Astemizole, one of the newer generation of nonsedating antihistamines, was evaluated in a double-blind study of forty-six patients who had chronic idiopathic urticaria with or without angioedema; most had severe disease. Nineteen of twenty-three patients who were on placebo discontinued treatment because of lack of response compared to only five of twenty-three astemizole-treated patients (p less than 0.0001). Fourteen of twenty-two astemizole-treated patients and two of twenty-two placebo-treated patients considered the results to be good or excellent (p less than 0.0001). Blinded assessment by the investigators yielded similar results (p less than 0.0001). Therapeutic response was the same in patients with and without angioedema in addition to urticaria and in those requiring corticosteroids. Duration of urticaria also did not influence the results. Increased appetite and weight gain were the main side effects reported more frequently in the astemizole-treated than in the placebo-treated group, and no significant toxicity was noted. Follow-up after terminating the drug study indicated a high frequency of remissions during the subsequent year.