Traditionally, direct anthropometry, two-dimensional (2D) photogrammetry and cephalometry have served as primary methods to quantify craniofacial characteristics. Stereophotogrammetry, a more recent method, is able to capture a three-dimensional (3D) image of a subjects facial surface almost instantaneously. This image can then later be measured in a variety ways, allowing the calculation of linear distances and the quantification of angles, surface areas and volumes. Several 3D stereophotogrammetric systems are commercially available and although some systems have been independently validated, little is known about how measurement data generated by different systems compare. The objective of this study is to evaluate the accuracy and precision of craniofacial measurements obtained using different 3D stereophotogrammetry systems (3dMDface and Vectra 3D) by comparing their values to each other and to measurements obtained using a Microscribe mechanical digitizer. The study sample consisted of 18 mannequin heads, pre-labeled with 28 anthropometric landmarks. All possible inter-landmark distances (n = 378) were calculated and several error magnitude statistics were used to compare facial measurement techniques: mean absolute difference (MAD), relative error magnitude (REM), technical error of measurement (TEM) and intraclass correlation coefficient (ICC). Overall, measurements across all three facial measurement techniques were highly comparable. Over 99% of MAD values were less than 1 mm and over 99% of REM scores were deemed excellent or very good (REM < 4%). Similarly, 100% of TEM values were less than 1 mm and the average ICC across all 378 measures was above 0.99 for all possible method comparisons. Based on the constructed confidence intervals, none of the observed MAD, REM, TEM or ICC values for any of the 378 variables significantly exceeded our predefined error thresholds (p > 0.05). Thermal maps depicting 3D surface-to-surface comparisons also showed negligible differences, with an average Root Mean Squared value across all 18 3D models of 0.197 mm. Results indicate that measurements derived from the Vectra-3D and 3dMDface imaging systems are virtually identical. Furthermore, both systems demonstrated similarly high levels of accuracy when compared to the Microscribe digitizer. Both imaging systems produce facial measurements sufficiently similar to allow for their data to be combined or compared statistically.

There are many orthodontic cephalometric analyses available. The emphasis in treatment planning has traditionally been hard tissue focused. This study evaluates a Soft Tissue Arc used in treatment planning. 30 profile images were morphed by 5 orthodontic residents and 5 orthodontic faculty. No statistically significant difference was observed between the morphing of the orthodontic faculty and residents. These same images were changed to match ideal values from a Soft Tissue Arc drawn from nasion with the center at center O. The Soft Tissue Arc changed the pictures differently than the orthodontic experts, however, there was no statistical difference in the final placement of soft tissue pogonion. These pairs of images (expert morphing vs Soft Tissue Arc changes) were then rated as more attractive or less attractive on a visual analogue scale by 5 orthodontic residents, 5 dental school faculty and 5 laypersons. Across the board, the images morphed by the experts received better ratings than the images changed by the Soft Tissue Arc. Laypersons were considerably less critical in their judgments, and overall gave higher ratings.

Objective: The objective of this in vitro study was to determine the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on the load-deflection properties of beta-titanium wires, specifically loading and unloading flexural modulus and yield strength. Materials and Methods: Ten 0.017 x 0.025 inch beta-tianium wires each from five companies were tested, using a three-point bend test apparatus, for a total of 50 control and 50 experimental samples. The experimental wires were exposed to MI Paste (CPP-ACP) for nine hours, to simulate three months of six-minute MI Paste application, before bend-testing in a water tank of 37 degrees Celsius, while the control wires were exposed to distilled water for nine hours before testing. A 2x5 multivariate analysis of variance was conducted to analyze the data. Results: There were no statistically significant differences between the control group and experimental group for loading elastic modulus, 0.2% offset yield strength, or unloading 0.2% offset yield strength. There was a statistically significant difference for unloading flexural modulus, but it is most likely not a clinically significant difference, given there was a 1.92% difference between the control and MI paste group. Conclusions: The results of this study suggest that CPP-ACP does not have any clinically significant effects on beta-titanium wires for the load deflection properties tested.

This project proposes to enhance technology aimed at improving osseointegration following dental implant. Specifically, we focus on the delivery of plasmid DNA (pDNA) using nanostructured hydroxyapatite particles coated on titanium surfaces. Our hypothesis is that localized expression of osteoinductive proteins will improve healing time and facilitate osseointegration, as well as enhance the efficacy of placing implants in porous type 4 bone. To evaluate the feasibility of intercellular gene delivery off titanium surfaces, we employed a reporter system of green fluorescent protein (GFP) pDNA-NanoCaP particles coated on a titanium surface. MG63 osteoblast cells were seeded on this surface, and later assayed for GFP expression. Twenty-four substrates were assessed: experimental group 2 (Exp2, 400 µl NanoCaP/ 8 µl pDNA) substrates group, demonstrated significantly higher GFP expression values compared to the control (Ctl, 200 µl of ddH2O and 4 µl of pDNA) and Exp (200 µl of NanoCaP and 4 µl of pDNA) groups. Our data show that the coated NanoCaP/pDNA complex can transfect plated cells and that the applied amount of NanoCaPs is critical. In conclusion, we have successfully shown the feasibility of a non-viral approach to deliver plasmid DNA from titanium surfaces and suggest that further optimization is needed.

Objective: The objective of this in vitro study is to compare measured values of pre-treatment tooth sizes and the Bolton overall and anterior analyses for fast-set plaster dental casts versus computer-based dental models made from a dual pour alginate impression. Materials and Methods: Maxillary and mandibular alginate impressions were made for a sample of thirty-six patients with permanent dentitions from first molar to first molar. Impressions were poured in fast-set orthodontic plaster within one hour and allowed to set for 8-10 minutes. Casts were removed from the impressions, cleaned of any observable plaster and re-examined for quality. Impressions were packaged and sent to OrthoCAD for generation of digital models. Measurements of mesiodistal tooth width were made using digital calipers or OrthoCAD proprietary software. Overall and anterior Bolton analyses were performed for all models. Measurements were repeated no less than two weeks later. Results were statistically analyzed for correlation coefficients and 2 x 2 MANOVA. Results: Correlations showed very high intrarater reliability for measurements made on both plaster and digital casts. Statistical significance was found for differences between plaster and digital casts in mesiodistal measurements of maxillary and mandibular anterior segments and total arch circumference, Bolton overall ratio and Bolton anterior ratio. Values of mean difference between plaster and digital casts for the anterior segment were 0.33 mm in the maxillary arch and 0.70 mm in the mandibular arch. Mean differences over the total arch were 0.68 mm in the maxillary arch and 1.35 mm in the mandibular arch. Value of mean difference between plaster and digital casts was 0.89% for the anterior Bolton ratio and 0.80% for the overall Bolton ratio. Conclusions: The results of this study show statistical differences for tooth size measurements between plaster casts made from the initial pour of alginate impressions and digital casts generated from the second pour. Statistical differences were also demonstrated for both the anterior Bolton ratio and total arch Bolton ratio, indicating differences between measurements were not the result of a uniform distortion occurring between the first and second pour. The small absolute value of mean differences may or may not have clinical significance. Individual practitioners should decide whether the absolute value for these small differences have clinical significance to their practice.

Thesis (M.S.)--University of Tennessee Health Sciences Center, 2005. / Spine title: Effects of sickle cell disease on growth of the craniofacial complexes. Appendices: leaves 162-414 Bibliography: leaves 145-161.