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Introduction The aim of this study was to determine whether the orthopedic forces of rapid maxillary expansion cause significant quantitative changes in the cranial and the circummaxillary sutures. Methods Twenty patients (mean age, 12.3 ± 1.9 years) who required rapid maxillary expansion as a part of their comprehensive orthodontic treatment had preexpansion and postexpansion computed tomography scans. Ten cranial and circummaxillary sutures were located and measured on one of the axial, coronal, or sagittal sections of each patient’s preexpansion and postexpansion computed tomography scans. Quantitative variables between the 2 measurements were compared by using the Wilcoxon signed rank test. A P value less than 0.05 was considered statistically significant. Results Rapid maxillary expansion produced significant width increases in the intermaxillary, internasal, maxillonasal, frontomaxillary, and frontonasal sutures, whereas the frontozygomatic, zygomaticomaxillary, zygomaticotemporal, and pterygomaxillary sutures showed nonsignificant changes. The greatest increase in width was recorded for the intermaxillary suture (1.7 ± 0.9 mm), followed by the internasal suture (0.6 ± 0.3 mm), and the maxillonasal suture (0.4 ± 0.2 mm). The midpalatal suture showed the greatest increase in width at the central incisor level (1.6 ± 0.8 mm) followed by the increases in width at the canine level (1.5 ± 0.8 mm) and the first molar level (1.2 ± 0.6 mm). Conclusions Forces elicited by rapid maxillary expansion affect primarily the anterior sutures (intermaxillary and maxillary frontal nasal interfaces) compared with the posterior (zygomatic interface) craniofacial structures.

The purpose of this study was to evaluate whether the home care of noncompliant adolescent orthodontic patients with "poor" oral hygiene could be improved through the use of a deception strategy designed to intentionally induce the Hawthorne effect. This effect is often cited as being responsible for oral health improvements of control groups that receive placebo treatments. It is thought that participating in and fulfilling the requirements of a study alters subjects' behavior, thereby contributing to the improvement. Forty patients with histories of poor oral hygiene were assigned, in a quasi-random fashion, to two groups. Experimental subjects (n = 20) were presented with a situation that simulated participation in an experiment. These included the use of a consent form; distribution of tubes of toothpaste labeled "experimental"; instructions to brush twice a day for two minutes using a timer; and a request to return unused toothpaste. Control subjects (n = 20) had no knowledge of study participation. Tooth surface area covered with plaque was used as a proxy measure of home care behavior. It was measured at baseline, three months, and six months. Mean percentages of tooth surface covered with plaque for the experimental and control groups were 71 (+/-11.52) and 74 (+/-11.46) at baseline; 54 (+/-13.79) and 78 (+/-12.18) at three months; and 52 (+/-13.04) and 79 (+/-10.76) at six months. No statistically significant difference (p > .05) was obtained between groups at baseline. Statistically significant differences (p < .05) were found between groups at three and six months. Significant differences (p < .05) were also found only for the experimental subjects between baseline and each of the two subsequent observation periods. The efficiency and potential effectiveness of this strategy suggest that additional research be conducted to assess oral health improvements and possible applications to the private practice setting.

The purpose of the present study was to evaluate the accuracy and reliability of airway volume digital measurements of cone-beam computed tomography (CBCT) compared with the manual measurements of an airway model. An acrylic airway model was constructed and attached to a human dry skull in the natural position of the airway passage. The total and internal airway volumes, as well as the most constricted airway area, were measured manually on the model and on the CBCTs taken after the model was attached to the skull. The CBCT images were analysed using the Dolphin3D (Dolphin Imaging & Management solutions, Chatsworth, California, USA) software. Reliability and accuracy were assessed by using intraclass correlation and Student's t-test. A P ≤ 0.05 was considered statistically significant. No significant statistical difference was found between the total, the internal airway volume, and the most constricted airway area measured on CBCTs compared with the manual measurements. The intra-examiner reliability was high for all measurements recorded from both methods (r ≥ 0.90). These results suggested that the three-dimensional CBCT digital measurements of the airway volume and the most constricted area of the airway are reliable and accurate. The use of CBCT imaging for the assessment of the airway can provide clinically useful information in orthodontics.

Surface-based and voxel-based superimposition methods using the anterior cranial base as a reference structure were accurate and reliable in detecting changes in landmark positions when superimposing. Landmark-based superimposition method was reliable but less accurate than the other methods.

Tricho-dento-osseous syndrome (TDO) Genet 1998;35:825-828)