Master of Science, The Ohio State University, 2018, Dentistry

Statement of problem. While the accuracy of digital implant impressions in single unit and short span situations has been demonstrated, the effect of various scan bodies and scan techniques on the accuracy and scan time in completely edentulous situations is not well understood. Purpose. The purpose of this study was to evaluate the effects of 4 different scanning techniques and 5 different commercially available intraoral scan bodies on the trueness (distance and angular deviation), precision (variance amongst the scans) and scan time in a completely edentulous situation with 4 implants. Materials and Methods. Five different intraoral scan body systems were evaluated: AF ( IO-Flo, Atlantis Denstply Implants), NT (Nt-Trading GmbH & Co. KG), DE (Dess-USA), C3D (Core3Dcentres NA), and ZI (Zimmer Biomet Dental), and 4 different scanning techniques were evaluated: unmodified master model (NO), glass fiduciary markers placed on the edentulous ridge (GB), pressure indicating paste brushed over the ridge and palate (PP), and floss tied between the scan bodies (FL). Five identical polyurethane edentulous maxillary models with 4 parallel dental implant analogs (TSV 4.1, Zimmer Biomet Dental) in the first molar and canine positions. The scan bodies were attached to the models and the entire surface was scanned using a calibrated structured blue light industrial scanner (Carl Zeiss Optotechnik GmbH) to generate a master reference model. Five consecutive digital impressions were made of the model using an intraoral scanner (Trios, 3Shape A/S) and 1 of the 4 techniques (n=5) assigned at random. The test scans were superimposed over the master reference model using a best fit algorithm, and then the distance deviation and angular deviation of the scan bodies was calculated. Scan time was also recorded. A two-factor ANOVA was used to examine the effect of scan body and technique on the trueness and on scan time, with subsequent Tukey or Bonferroni-corrected Student's t-tes (open full item for complete abstract)

Committee: Burak Yilmaz DDS, PhD (Advisor); Edwin McGlumphy DDS, MS (Committee Member); Jeremy Seidt PhD (Committee Member); William Johnston MS, PhD (Committee Member) Subjects: Dentistry

Master of Science, The Ohio State University, 2014, Dentistry

Enamel defects in primary teeth predispose children to early childhood caries and are often not detected nor intervened upon until damage from caries has occurred. In this study, we utilized a novel imaging device, the ProScope digital microscope, to assess the enamel quality in vivo of young children ages 9 months -3 years. We also used a parental survey and medical record review to elucidate factors leading to defects in our population. Based on clinical exam, patients were separated into intact and defective enamel groups. The final sample included 45 children with intact enamel and 30 children with enamel defects. ProScope images were captured with a 100x lens during the exam and were later assessed based on the modified Developmental Defects of Enamel index by five raters. We found that children in the defective enamel group had higher dft scores of 1.34 vs. 0.29 (p=0.008), more caregivers who smoke in the home at 50% vs. 26.7% (p=0.04), and more parents reporting soft teeth in their children at 33% vs. 6.7% (p=0.003). The ProScope, when compared to the gold standard of visual clinical exam for detecting enamel defects, had a sensitivity of 82.7% and specificity of 77.3%. We found an inter-rater reliability of 0.438 among the five raters. We concluded that enamel defects in primary teeth might be the missing link between maternal smoking and offspring caries rates as reported in previous studies. Additionally, children with enamel defects and children identified by their parents as having soft teeth had a higher risk of dental caries, and therefore those children should receive increased preventive care and counseling. The ProScope was useful for evaluating enamel defects, but might be best suited for serial evaluation of enamel defects and incipient carious lesions to document progression over time in the same patient.

Committee: Ann Griffen DDS, MS (Advisor); Paul Casamassimo DDS, MS (Committee Member); Robert Rashid DDS (Committee Member) Subjects: Dentistry; Health Care