Faculty Bibliography

The purpose of this study was to compare soft tissue prediction accuracy of model surgery combined with computer software prediction with that of computer software prediction alone and to assess surgical accuracy by comparing the immediate postsurgical cephalogram with the planned movement of skeletal hard tissue. The predicted and actual soft tissue changes and the corresponding skeletal changes of 16 patients were compared using the Quick Ceph Image cephalometric treatment simulation software. A custom analysis was created to measure the hard tissue and soft tissue changes that occurred as a result of the surgical procedure. On average, the predictions were not significantly different from the actual postsurgical profile changes. Surgical changes of hard tissues from presurgery to postsurgery were accurate as planned except for the position of N-ANS. All lower soft tissue points moved significantly during treatment. Quick Ceph Image offers a rapid and reliable method of profile prediction that does not require artistic skill. If predictions are interpreted with caution and transferred accurately to the model surgery, they can provide an excellent visual aid during presurgical treatment planning and patient presentation

PURPOSE: This study was performed to compare the dimensions of the nasopharynx, oropharnynx, and hypopharynx of persons with hyperdivergent and normodivergent facial types, and to determine whether any variations exist. PATIENTS AND METHODS: Lateral cephalometric records of a population with a normodivergent facial pattern (n = 23) and a group with a hyperdivergent facial pattern (n = 27) as evidenced by increased mandibular plane angle were used to compare the soft tissue airway dimensions. Statistical analysis consisted of Student's t-tests, Wilcoxon rank sums, and chi2. Statistical significance was set .05. RESULTS: Overall the hyperdivergent group had a narrower anteroposterior pharyngeal dimension than the normodivergent control group. This narrowing was specifically noted in the nasopharynx at the level of the hard palate and in the oropharynx at the level of the tip of the soft palate and the mandible. In addition, the posterior pharyngeal wall had a thinning at the level of the inferior border of the third cervical vertebrae, and there was a more obtuse palatal angle. The tongue was also positioned more inferiorly and posteriorly in the hyperdivergent group, as evidenced by the increased distance between the hyoid bone and the mandibular plane and the increased distance between the soft palate tip and the epiglottis. The hyperdivergent group had more retruded maxillary and mandibular apical bases and a higher Class II skeletal discrepancy. CONCLUSIONS: The narrower anteroposterior dimension of the airway in hyperdivergent patients may be attributable to skeletal features common to such patients, that is, retrusion of the maxilla and the mandible and vertical maxillary excess. Other features, such as an obtuse soft palate and low-set hyoid, also may be contributory factors. The relatively thin posterior pharyngeal wall observed in hyperdivergent patients might be a compensatory mechanism

PURPOSE: Manufacturers commonly provide information on the physical properties of dental materials, but information on their antibacterial properties is often missing. This study determined the antibacterial properties of four currently used orthodontic band cements against three different strains of Streptococcus mutans. METHODS: The cements utilized were Durelon, Ketac, Mizzy Zinc Phosphate, and Band-Lok, a recently introduced, resin-based, dual-cure glass ionomer cement. Disk diffusion assay methodology was used to test for zones of bacterial inhibition around cement samples. Zones of inhibition were measured in millimeters using an electronic caliper. In addition to cured cement plugs and freshly mixed cement samples, a new variation, in the form of a cement plug surrounding a stainless-steel band, was tested. Twelve combinations resulted from the four cement types and three forms. RESULTS: Of the variables studied, the mix forms of Durelon, Ketac, and Mizzy Zinc Phosphate cement showed the greatest bacterial inhibition (Kruskal-Wallis, P < 0.05). Among the cements tested, Mizzy Zinc Phosphate showed the largest zones of inhibition, with Durelon and Ketac having comparable zones of inhibition (Kruskal-Wallis, P < 0.05). Band-Lok did not exhibit an inhibitory effect against any of the three strains of S. mutans tested. CONCLUSION: A 'containment effect' of no bacterial inhibition was observed in the cement samples surrounded by the stainless-steel band material

Recently, the ion-implantation process has been applied to orthodontic wires. By altering the surface composition of a wire, the ion-implantation process supposedly decreases the frictional forces produced during tooth movement. The purpose of this study was to compare the amount of tooth movement produced by different orthodontic wire compositions, under identical conditions, by using an in vitro model. The wires tested were stainless steel, nickel-titanium (control and ion implanted), and beta-titanium (control and ion implanted). The amount of tooth movement was measured and compared. Results demonstrate that, stainless steel produced the least frictional force during in vitro tooth movement, followed by ion-implanted nickel-titanium, ion-implanted beta-titanium, untreated nickel-titanium, and finally, untreated beta-titanium. A Wilcoxon rank sum test showed statistically significant differences in the amount of movement seen with the ion-implanted wires when compared with their untreated counterparts

This study investigated the effect of the palatal crib appliance used in the correction of open bite malocclusions secondary to fingersucking. Twelve experimental and 12 control subjects were studied for an average of 3.9 months. The sample consisted of patients who were both growing and not growing. Study models taken before and after the study period were analyzed for changes in the following dimensions: overbite, overjet, arch perimeter, arch length, and incisor angulation. Data were analyzed with student t-tests to determine statistical significance. Partial or complete closure of the open bite was achieved averaging 3.7 mm +/- 1.9 mm during the observation period in the experimental group treated with palatal crib therapy. In contrast, the control group displayed a mean bite opening of 0.4 mm +/- 0.8. These values were statistically significant at the P < 0.001 level. Open bite decreased as incisor angulation (P < 0.02), arch length (P < 0.05), and arch perimeter (P < 0.01) decreased. Overjet changes were minimal and statistically insignificant

The purpose of this study was to test and compare the accuracy and reliability of soft tissue profile predictions generated from two computer software programs. The presurgical and postsurgical cephalometric radiographs of 28 patients were digitized onto each computer program. A customized analysis was created to determine the amount of surgical movement, as well as to compare the actual postsurgical soft tissue profile with the computer-generated prediction. The results demonstrated that, on the average, the predictions were not significantly different from the actual postsurgical profile changes. While each program generated statistically similar prediction results, marked variability was noted. There was no significant difference found in the prediction errors between patients who had one-jaw surgery and those who had two-jaw surgery. This study found that a linear relationship existed between the surgical movement and the prediction error. In general, the greater the magnitude of the surgical movement, the larger the prediction error

Cephalometric radiography is an important diagnostic aid in orthodontics. Mesh analysis is a proportionate cephalometric method of graphically assessing disharmonies of the craniofacial complex. Original norms for this analysis were created from a white, European American sample. Norms for black Americans of African descent were developed in another study. The purposes of this investigation were: (1) to develop a standard mesh diagram from a Puerto Rican American population; (2) to compare the diagram with previously established data from the white sample; (3) to develop linear and angular means for the Legan, Burstone, Ricketts, DiPaolo, and Steiner analyses for a Puerto Rican American population; and (4) to assess the use of a panel for selecting esthetically pleasing faces. The subjects in the study had no previous orthodontic treatment, had Class I occlusion with 6 mm or less of crowding per dental arch, and had two parents and two sets of grandparents who were were born in Puerto Rico. Sixty-nine patients met the study criteria, and 50 of those patients (20 males and 30 females) were selected as having esthetically pleasing faces by the panel. Male and female norm diagrams were created and these were compared with those developed previously. Linear and angular measurements were also compared. Significant differences between the ethnic groups were found in the dentoalveolar region. Similarities were noticed in the upper face height and anterior cranial base length. The panel selection results showed no agreement within the sexes, occupations, or ethnic groups

Orthodontic patients have reported the use of analgesics during therapy. However, common anti-inflammatory analgesics, such as aspirin and ibuprofen, have been shown to slow the rate of tooth movement. Acetaminophen, another common analgesic, does not possess anti-inflammatory properties. The effect of acetaminophen on tooth movement was studied using New Zealand white rabbits. Experimental animals were matched to a control animal of the same sex and weight. Under anesthesia, springs were ligated between the lower first molar and incisor, resulting in approximation of these teeth. Under blinded conditions, seven of the rabbits received 1000 mgs of acetaminophen daily. Seven control animals received water. The animals were sacrificed after 21 days. The movement of incisors and molars was measured. Results showed considerable movement within both the experimental and control groups, but no significant difference in tooth movement between them. Acetaminophen has no effect on the rate of tooth movement in rabbits undergoing orthodontic treatment