A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Purpose: This study will evaluate the influence of different convergence angles and tooth preparation heights on the marginal adaptation and retention of allceramic CAD/CAM crowns. Materials & Methods: Seventy two typodont teeth (Ivorine teeth; Columbia Dentoform Corp, Long Island City, NY) were prepared using milling burs (Brasseler, USA) and a parallometer (PFG 100, Cendres and Metaux, Switzerland) with 1.0 mm rounded shoulder finish lines. Specimens were divided into 3 groups (n=24) according to 3, 4.5 and 6mm occluso-gingival (O-G) heights. The teeth within each group were then subdivided into 3 subgroups (8 in each sub-group) according to total occlusal convergence (TOC) of 8,16 and 22 degrees. Using the intra-oral camera wand of the Cerec AC machine (Sirona, Germany), optical impressions were made of each tooth. This data was then transferred to the Cerec MC XL milling unit for fabrication of all-ceramic crowns using IPS Empress II (Ivoclar Vivadent, US). The crowns were cemented on typodont teeth with glass ionomer cement. The marginal discrepancy was measured at 6 points with optical microscopy. Retention was evaluated by measuring the tensile force required to dislodge or break the crown from the corresponding tooth preparation in a universal testing machine. Data were analysed using Shapiro-Wilke tests for normality and Leven's tests for equal variances. To look for differences between groups, analysis of variance (ANOVA) with Tukey's HSD test was performed. Results: Mean marginal gap was 35.9 ± 18.4ìm to 81.4 ± 61.3ìm. 2- way ANOVA shows no significant difference in marginal gap among the groups (P< 0.05). The height mean retentive force 183.84 ± 27.0 N, was measured for 6mm height and 8° group and lowest force 86.01±10.75 N, was measured for 3 mm and 22° group. 2- way ANOVA with turkey's HSD test shows significant difference among the groups (P > 0.05). Conclusion: Marginal adaptation of the CAD/CAM all-ceramic crowns is comparable to conventional cast crowns. The preparation recommendation for conventional porcelain fused to metal crowns can be applied to CAD/CAM crown restorations. Retention of cemented CAD/CAM crowns is comparable to conventional cast crowns

Background. There are many polishing systems available on the market have been used by many clinicians to improve the color stability, wear resistance and surface smoothness of composite restorations. Several changes have been made in the fabrication of dental resin composites to improve their mechanical strength and esthetic properties. Previous studies have shown that composite resins are susceptible to color instability because of surface roughness and exposure to various staining media, especially red wine, coffee, soda and tea. The purpose of this study was to evaluate the average surface roughness (Ra) and color stability of two direct resin compositespolished with four different polishing systems. Methods. Two resin composites (nanohybrid and nanofill) were evaluated using four polishing systems (Four versus three steps; diamond versus fluted burs). A disk-like specimen of each composite material was fabricated (10 mm in diameter and 2 mm thick). Ten specimens of each composite were randomly assigned to one of four polishing systems. The surface roughness values were measured using the profilometer. In addition, discoloration of the polished composites was evaluated after immersion into different solutions, namely coffee and red wine. The staining of the materials was evaluated using the spectrophotometer. Results. No difference was noted between any of the four different polishing techniques, type of composite and surface roughness (Ra). A one way ANOVA showed that there was a statistical significant difference between color change (ΔE) and polishing techniques, p

May 2008. A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

June 2008. A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

June 2010. A thesis submitted to the College of Dental Medicine of Nova Southeastern University in partial fulfillment of the requirements for the degree of Master of Science [Dental Medicine].

June 2010. A thesis submitted to the College of Dental Medicine of Nova Southeastern University in partial fulfillment of the requirements for the degree of Master of Science [Dental Medicine].

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Abstract ASSESSMENT OF THE ROLE THAT SECOND MOLARS PLAY IN BITE-OPENING DURING ORTHODONTIC TREATMENT IN ADOLESCENTS: A RETROSPECTIVE, CEPHALOMETRIC STUDY DEGREE DATE: DECEMBER 6, 2013 Christopher B. Trockel, D.D.S. COLLEGE OF DENTAL MEDICINE NOVA SOUTHEASTERN UNIVERSITY Thesis Directed By: Shiva Khatami D.D.S., Ph.D, Committee Chair Mark Hall, D.D.S., Committee Member Abraham Lifshitz, Committee Member Objectives: This study aimed to investigate the role that second molars play in increasing the facial vertical dimension by comparing vertical changes experienced in growing patients, who had their second molars incorporated into the orthodontic appliance, with those that did not. The study investigated associations between the vertical changes experienced through treatment and the initial vertical classification of the patients (normo-, hypo-, and hyperdivergent). Background: Many studies have investigated the changes in the vertical dimensions that occur in orthodontic treatment. It has been shown that almost all orthodontic appliances produce extrusion whether desired or not. In theory, this extrusion may lead to an increase of the skeletal vertical dimension. Conventional wisdom says that second molars play a significant role in vertical control during treatment. Therefore, some practitioners advocate viii incorporating the second molars as soon as possible in treatment to help open the bite. It is also thought that it may be wise to not incorporate the second molars during treatment at all in cases with an open bite tendency. Methods: Eighty de-identified pre-treatment cephalometric radiographs (40 with second molars bonded and 40 without second molars bonded) from growing patients treated at the orthodontic clinic at Nova Southeastern University were analyzed and compared to their post-treatment analogs. Twelve linear and angular measurements were made (overbite, maxillary molar to palatal plane, mandibular molar to mandibular plane, upper anterior dentoalveolar height, lower anterior dentoalveolar height, upper anterior facial height, lower anterior facial height, total posterior facial height, lower posterior facial height, UAFH/LAFH ratio, mandibular plane angle, and Y-axis). Results: The results indicated that the vertical dimension was not significantly altered based solely on whether or not the second molars were incorporated into the orthodontic appliance. Changes experienced by both groups (bonded and non bonded) and all three subgroups (hypo-, normo-, and hyperdivergent) were consistent with what would be expected for growth alone. Conclusion: Bonding second molars in a growing population during orthodontic treatment does not significantly affect the vertical dimension, regardless of the patient's initial skeletal vertical classification.

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Background. Earlier research evaluated the 3D internal fit of CAD/CAM crowns after direct versus indirect laser scanning. To date, no study has evaluated the marginal integrity of all-ceramic crowns milled with different type of scanning systems via different methods of scanning. The purpose of This study was conducted to assess the marginal integrity of all-ceramic crowns milled with the E4D CAD/CAM system (D4D, Richardson, Texas) using three different scanning methods of a prepared model (direct scanning and indirect scanning of a cast, and scanning of an impression material). Methods. A metal die model of a prepared mandibular first molar was fabricated according to specifications for tooth preparation for the E4D CAD/CAM system. Fifty five all-ceramic crowns were milled using this system: 5 crowns were made from scanning of the metal die; 25 crowns were made from scanning of 5 PVS impressions of the metal die, with each impression scanned 5 times; and 25 crowns were made from scanning stone dies poured from the same previous 5 PVS impressions. Each stone die was scanned 5 times. An internal gap to provide space for cement was kept constant at 25 microns. Marginal integrity of the crowns was assessed using optical microscopy. Results. The overall mean marginal gap and standard deviation for crowns was 78.1&mgr;m (18.9) for scanning the metal dies, 148.9&mgr;m (25.4) for scanning impressions and 126.2&mgr;m (28.2) for scanning the stone casts. ANOVA revealed significant differences in marginal gap between the three different groups. Conclusions. The direct scanning of a metal die produced crowns with significantly smaller marginal gaps than the marginal gap seen from scanning a PVS impression or a stone cast (P<.05). Additionally, it was found that scanning PVS impressions or stone casts, produced crowns with unacceptable mean marginal gaps (over 120&mgr;m). It was also observed that difficulty of scanning PVS impressions and tracing the finish line lead to overhanging margins and larger marginal gaps for both crowns produced via that method.

Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this study was to determine the rate of plaque formation in children and its relationship to their periodontal and caries indices and to evaluate a television area measurement instrument. Plaque formation at 6-, 24-, 48-, and 96-hour intervals was observed in 56 children aged 8 through 12 to establish the rapidity of its reformation after a thorough dental prophylaxis. The plaque was recorded with disclosing agents and oriented Polaroid photographs and measured by newly developed television and electronic area measurement instrumentation which proved to be highly reliable. The presence of caries and periodontal disease was then correlated with the amount of plaque recorded at each observation period. A high correlation was found between the Anterior P-M-A and the Periodontal Index. No significant correlations were found between the periodontal indices and the DMFs scores or with the amount of plaque present and the DMFs scores. Seventy-seven per cent of the children displayed measurable amounts of plaque just 6 hours after a thorough dental prophylaxis. In comparing the amount of plaque formed by these children with results reported from similar studies conducted on adults, it is apparent that children in this age group form more plaque in less time than adults. A significant correlation was found between the amount of plaque present and the periodontal indices at the 48-hour examination.

Indiana University-Purdue University Indianapolis (IUPUI) / The need for a safe but effective agent to sedate dental patients who are severe behavior management problems prompted this investigation of ketamine HCl. Ketamine HCl is a general anesthetic agent with the unique property of selectively depressing the higher centers of the brain without adversely affecting respiration or cardiac output. Sixty behavior problem pedodontic patients were selected at random and placed in one of three groups to receive the following treatments: Treatment I - ketamine HCl and scopolamine; Treatment II - ketamine, scopolamine, and droperidol, and Treatment III - ketamine, scopolamine, and nitrous oxide-oxygen analgesia. Each treatment group received ketamine HCl 2 mg/lb and 0.1 - 0.3 mg scopolamine. The second two treatment groups were supplemented with droperidol .025 mg/lb or nitrous oxide-oxygen (20-50%) to maintain anesthesia. The patients were given a series of pre and post-treatment mental and physical tests and were considered completely recovered when they could equal their pre treatment test scores. Routine dental restorative procedures limited to one and one-half hours were carried out with the use of the ruber dam. Onset of anesthesia was five minutes for all three treatment groups. Treatment III showed a significantly longer working time but recovery times were not significantly different between groups. Ketamine HCl was determined to be a safe, effective agent for use in pedodontic outpatients provided prescribed techniques are followed. Complications were infrequent and minor and parental response was considered satisfactory.