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Introduction: We argue, for studies of growth or treatment changes, superimposed CBCT images ought to be employed routinely. The location of 3D landmarks on curved structures, however, has been complex. In this study, a reliable method of CBCT superimposition was developed with the aid of AMIRA XImage® software. The specific focus was to develop a practical method for cranial base superimpositions at sella turcica in serial CBCT images. Subsequently, evaluations of the anterior curvature of hypophyseal fossa during growth were completed to confirm the stability. Comparisons of surface changes in the superimposed images in different regions were also made. Methods: Samples of pre- and post-orthodontic CBCT data were procured from Case Western Reserve University. Cranial base changes in 10 adolescent patients of Class I and II hypodivergent, normodivergent, and hyperdivergent malocclusions, were observed over an average interval of 2 years and 5 months. Cranial base models were superimposed using a rigid registration technique, and 3D models constructed from manual segmentation in the AMIRA software. Surface distance changes of the entire cranial base were compared to that of the anterior portion of sella turcica. Results: Mean surface distance changes for the entire cranial base and anterior sella were 0.73-1.57 ± 0.71-1.30 mm and 0.37-0.63 ± 0.29-0.43 mm, respectively. The area above a threshold of 0.5 mm was 61.02-74.11% (cranial base) and 40.70-50.94% (anterior sella) as well. Paired t-tests were applied to compare differences between the mean distance and area above the threshold for data of cranial base versus anterior sella. Both illustrated p-values less than 0.0001 and were statistically significant. Intra-rater reliability was evaluated by completing segmentation and registration three consecutive times on each CBCT volume. Mean surface differences were within 0.01 mm with the exception of one patient. In addition, all subjects exhibited less than 1.00% deviation except three patients, which deviated by 1.03%, 1.46%, and 1.64%, respectively. Conclusions: A practical method of superimposition of serial CBCT images was developed. Through production of color maps, the surface distance of the anterior portion of sella turcica was shown to change much less than the clivus and remaining cranial base structures in pre- and post-treatment scans of growing children. Lastly, the method of superimposition developed here may assist future studies of skeletal changes with accuracy. / Oral Biology

Objectives: With increasing utilization of cone beam computed tomography for diagnosis and treatment planning of complex dentomaxillofacial rehabilitation, more incidental findings of pathology in the maxillary sinus have been identified by clinicians. Part one of this article discusses the association between age, gender, ethnicity and dentition status in relation to prevalence of sinus pathology. The aim of this study is to expand the current knowledge base in regards to the prevalence of maxillary sinus pathologies in patients of Temple University Kornberg School of Dentistry and to determine if smoking and allergies have relationship with the prevalence of pathology. Materials and Methods: : Three hundred and sixty-three cone beam computed tomography scans taken were evaluated at Temple University Kornberg School of Dentistry Department of Oral and Maxillofacial Radiology between 2009 to July 31, 2013. Scans were classified into 1 of 5 categories based upon the type of sinus pathology detected. The categories of sinus findings were: healthy, mucosal thickening > 3-4 mm, polypoidal mucosal thickening, partial opacification and complete opacification. Medical health questionnaires were reviewed for patient's social history such as smoking and systemic factors such as allergies. Chi-square statistical analysis using SAS was done to examine the relationship. Results: This study included a total of 363 subjects subdivided by gender into 203 females and 160 males. The subjects were further subdivided by ethnicity into 217 Caucasians, 86 African Americans, 35 Asians, and 25 Hispanics. Also, 129 of the subjects had a history of smoking, 98 had seasonal allergies, and 50 had environmental allergies. In addition 129 of the subjects had at least 1 type of sinus pathology. Chi-square analyses showed that there was no relationship between the prevalence of sinus pathology and allergy or smoking status. History of allergies was marginally higher in females and significantly higher in African Americans (p=0.007). History of smoking was higher in older subjects (p=0.0004), males (p=0.01) and Caucasians (p<0.0001). Conclusions: This CBCT cross sectional study shows that there is no statistically significant correlation between prevalence of sinus pathology and smoking or allergy status. Further cohort studies are needed to determine if smoking or allergies may or may not contribute to sinus pathology. / Oral Biology

There are numerous examples in the literature of time-dependent changes in the proper-ties of sands, or aging effects. Most of these aging effects are of increases in the cone penetration resistance. Time-dependent increases in penetration resistance have been measured in hydraulically placed fills and freshly densified deposits, with the largest in-creases following the use of ground modification techniques such as vibrocompaction, dynamic compaction, and blast densification. It is not known what causes these increases in penetration resistance to occur. The objective of this research was to gain an understanding of the possible mechanisms responsible for aging effects in sands. Current hypotheses to explain what causes aging effects in sands include increased interlocking of particles, internal stress arching, and precipitation of silica or carbonate minerals at the contacts between grains. To date, no unambiguous evidence has been presented to support these hypotheses. A laboratory testing program was developed to study the influence of different variables on the pres-ence and magnitude of aging effects. Three different sands were tested in rigid wall cells and buckets. Samples were aged under different effective stresses, densities, tempera-tures, and pore fluids. In every rigid wall cell, three independent measurements were made to monitor property changes during the aging process: small strain shear modulus using bender elements, electrical conductivity, and mini-cone penetration resistance. At the end of each test, detailed mineralogical tests were performed to assess changes in the chemistry of the samples and pore fluids. A total of 22 tests in rigid wall cells were per-formed with periods of aging ranging from 30 to 118 days. Mini-cone penetration resis-tances were measured in the buckets before and at various times during the aging process. Increases in the small strain shear modulus were measured with time. It was found that sand type and pore fluid composition greatly influenced the amount of increase in small strain shear modulus. Density was also found to influence the amount of increase in small strain shear modulus. Temperature was found to have little influence on the in-crease in small strain shear modulus with time. Changes in the chemistry of the samples were also measured with time. The dissolution and precipitation of minerals in solution was monitored with electrical conductivity measurements. In most of the tests, there was continual dissolution of minerals with time. Mineralogical studies and conductivity measurements indicated precipitation of carbonates and silica in two of the tests; however, scanning electron micrographs showed no visible evidence of precipitation. Despite the measured increases in small strain shear modulus and evidence of mineral precipitation, there were no increases in the mini-cone penetration resistance with time. This finding is significant and suggests that small-scale laboratory experiments do not capture the mechanism(s) that are responsible for time-dependent increases in penetration resistance in the field. / Ph. D.

The current approach for using cone penetration test data to estimate soil behavior during seismic loading involves the comparison of the seismic stresses imparted into a soil mass during an earthquake to the penetration resistance measured during an in-situ test. The approach involves an indirect empirical correlation of soil density and other soil related parameters to the behavior of the soil during the loading and does not involve a direct measurement of the dynamic behavior of the soil in-situ. The objective of this research was to develop an approach for evaluating the in-situ behavior of soil during dynamic loading directly through the use of a vibrating piezocone penetrometer. Cone penetration tests were performed in a large calibration chamber in saturated sand samples prepared at different densities and stress levels. A total of 118 tests were performed as part of the study. The piezocone penetrometer used in the investigation was subjected to a vibratory load during the penetration test. The vibratory units used in the investigations were mounted on top of a 1m section of drill rod that was attached at the lower end to the cone penetrometer. Pneumatic impact, rotary turbine, and counter rotating mass vibrators were used in the investigation. The vibration properties generated by the vibratory unit and imparted into the soil were measured during the penetration test by a series of load cells and accelerometers mounted below the vibrator and above the cone penetrometer, respectively. The tip resistance, sleeve friction and pore water pressure were also measured during the test by load cells and transducers in the cone itself. The vibration and cone data were compiled and compared to evaluate the effect of the vibration on the penetration resistance and pore water pressure in the soil mass. The results of the testing revealed that the influence of the vibration on the penetration resistance value decreased as the density and the mean effective stress in the soil increased, mainly because the pore water pressure was not significantly elevated throughout the entire zone of influence of the cone penetometer at the elevated stress and density conditions. An analysis of the soil response during the testing resulted in the generation of a family of curves that relates the soil response during the vibratory and static penetration to the vertical effective stress and density of the soil. The data used to generate the curves seem to agree with the proposed values estimated through the empirical relationship. An evaluation of the effects of the frequency of vibration was also performed as part of the study. The largest reduction in penetration resistance occurred when the input vibration approximated the natural frequency of the soil deposit, suggesting that resonance conditions existed between the input motion and the soil. An energy-based approach was developed to compare the energy imparted into the soil by the vibrator to the energy capacity of the soil. The input energy introduced into the soil mass prior to the reduction in penetration resistance agrees well with the energy capacity of the soil, especially in tests at the low effective stress level where a high excess pore water pressure was observed. / Ph. D.