Objectives: The aim of this study is to investigate the impact of multiple factors in the Oral Health Related Quality of Life of patients being treated with Conventional Complete Dentures, including: a) Level of expertise of the dental provider (third year dental student vs. fourth year dental student); b) Length of time edentulous; c) Number of previous prostheses; d) Race; e) Sex; f) Age; g) Systemic conditions; h) Condition of the bone ridge; i) Economic factor and insurance coverage, in patients at the University of Iowa College of Dentistry (D3 and D4 Clinics). Materials and methods: Eighty-one subjects who had been completely edentulous (49 men and 32 women; age range from 23 to 93 years old, mean of 58.9+13) for a minimum of 3 months were recruited. Out of the eighty-one, eleven subjects were not included in the final analysis because their prostheses were not delivered due to various reasons (time, death, discontinued treatment). Subjects were asked to complete the OHIP-EDENT (Oral Health Impact Profile for Edentulous Patients) and the patient satisfaction questionnaire to record data at baseline, at 1-week post-delivery and at 1-month post-delivery of the new prostheses. Additional to these two instruments, the PDI Classification instrument (to assess bone/tissue condition) and the Kapur Index (to assess retention/stability of the new prostheses) were also used. Baseline comparisons of subjects seen at the D3 vs. the D4 clinic were carried out using chi-square tests of association for nominal ordinal variables, and the Wilcoxon-Mann-Whitney test for ordinal and quantitative outcomes. Bivariate analyses were conducted to assess potential relationships between covariates and the primary outcomes (total OHIP-EDENT and total Patient Satisfaction Questionnaire scores at one-week and one-month follow-ups). The Spearman rank correlation was used to identify increasing or decreasing relationships between primary outcomes and quantitative and ordinal variables; the Wilcoxon-Mann-Whitney test was used to assess relationships between primary outcomes and categorical covariates. Results: Overall, there was not enough statistical evidence to conclude that patient satisfaction and quality of life were significantly affected by most of the factors being studied. However, there was suggestive evidence of the presence of higher level of quality of life for patients seen in the D4 clinic (students with higher level of expertise). At the one-month follow-up, the comparison of the total OHIP-EDENT score between the D3 and D4 clinics was significant at the 0.05 level (p=0.018, exact Wilcoxon-Mann-Whitney test). The total OHIP-EDENT scores tended to be lower (indicating greater satisfaction) in the subjects seen in the D4 clinic. Two of the nineteen items from the patient satisfaction questionnaires also suggested a greater level of patient satisfaction for patients seen in the D4 clinic (students with higher level of expertise). Conclusion: 1) Oral health related quality of life at 1-week follow-up was not significantly different between patients treated by D3 and D4 students. 2) Oral health related quality of life at 1-week follow up was significantly better for patients who had been edentulous for a longer period of time than those who were recently edentulous. However, this result can only be considered suggestive due to the need for adjustment for multiple comparisons. 3) Oral health related quality of life at 1-month follow up was significantly better for patients treated by D4 students in comparison to D3 students. However, this result can only be considered suggestive due to the need for adjustment for multiple comparisons. 4) Overall, patient satisfaction at 1-week follow-up was not significantly different between patients treated by D3 and D4 students. However, patients treated in the D4 clinic reported significantly better outcomes in regard to speaking with their new prostheses. 5) Overall, patient satisfaction at 1-month follow-up was not significantly different between patients treated by D3 and D4 students. However, patients treated in the D4 clinic reported that they could chew better with their new prostheses compared to those treated by D3 students.

Objective: An in vitro study to determine the age and gender related changes of dental pulp stem cells in regards to proliferative capacity and lineage dependent effects on differentiation capabilities. Material and Methods: Specimens have been collected from a population ranging from 16 yrs of age to 78 yrs of age. Intact, non-carious teeth were collected from the oral surgery department at College of Dentistry at the University of Iowa. A total of 20 specimens were collected. Teeth were collected, sectioned and pulpal tissue collected from the specimens. The pulpal tissue was cut and stored in phosphate buffered saline. The tissue was then subjected to enzymatic digestion and DPSC isolation. Subsequently cell cultures were grown, percentage of Stro-1+ cells and proliferation rate were measured. The DPSC were subjected to differentiation via osteogenic and adipogenic medium. The cells were assessed for osteogenic and adipogenic characteristics using RT- PCR and also replicative senescence using telomere length ratio measurement. Results: Data suggests that with increasing age, there is a decreased proliferative capacity, decreased osteogenic capacity and shortened telomere length. There is no difference in the adipogenic potential and the percentage of DPSC present. There appears to be no difference in DPSCs in regards to proliferative capacity and differentiation potential with regards to gender. A possible gender related effect was noted in osteogenic potential and telomere length. Conclusion: Increasing age has both a decreased proliferative effect and lineage dependent effects on DPSC differentiation potential. Thus this relationship must be accounted for when developing future regenerative therapies.

Purpose: the purpose of this study was to evaluate the effect of annealing heat treatment on biaxial flexural strength and reliability of 3Y-TZP, sintered at various temperatures. Materials & methods: 3Y-TZP blanks were pre-sintered at 850°C for 2 hours and sliced into discs (20x1.2mm). Specimens were randomly assigned to 5 groups and subsequently sintered at various temperatures ranging from 1350°C to 1650°C for 2 hours. For each sintering temperature, specimens were divided into three treatment groups. One group (n=20) was left as-sintered as control. One group was air-abraded with 50 micron aluminum oxide powder (n=20). The last group was air-abraded and heat-treated at 1250°C for 20 minutes (n=20). In addition, polished specimens (n=5 per sintering temperature) were prepared to study microstructure, grain size and indentation crack patterns. The mean density was measured by helium pycnometry. The percent porosity was calculated from measured and theoretical density. The mean grain size was determined by the linear intercept method on atomic force micrographs. Crystalline phases were analyzed by x-ray diffraction (XRD). Biaxial flexural strength (BFS) was tested according to ISO standard 6872 using a Universal Testing Machine. Polished specimens were thermally etched, gold coated and Vickers indentations were produced under a 98N load. Indentation crack patterns were analyzed by Scanning Electron Microscopy (SEM) on digital images. The length ratio of trans-granular to inter-granular fracture was determined. Results were analyzed by Kruskal-Wallis test and Turkey's adjustment for multiple comparisons. A 0.05 level of segnificance was used. Reliability was evaluated by weibull analysis. Results: There was an inverse relationship between density and sintering temperature Spearman rank correlation r = -0.982, p<0.0001). Statistically significant differences were found between all the groups (p<0.0001, exact Kruskal-Wallis test). There was strong evidence of an increase in the percentage of porosity with increasing sintering temperature Spearman rank correlation r=1.00, exact p = 0.017). The mean real grain size increased with sintering temperature. Analysis of XRD data showed that the monoclinic phase as well as ferro-elastic domain switching were present for all air-abraded groups. A small amount of monoclinic phase was also present in groups sintered at 1600°C and 1650°C. In The mean BFS was higher for all air-abraded groups compared to as-sintered or air abraded and heat-treated groups. Air-abraded groups sintered at 1350, 1450, 1550, and 1600°C showed the highest mean BFS (1552.97±200.85, 1502.29±102.36, 1391.4±108.3, 1258.5±114.8 MPa), respectively. The highest Weibull moduli (reliability) were obtained with the heat-treated group sintered at 1550°C (19.8), air-abraded group sintered at 1450°C (17.6) and heat-treated group sintered at 1350°C (15.4). The group sintered at 1650°C was the least reliable, independently of treatment state. Based on the data analysis of both the biaxial flexural strength and Weibull modulus, it was found that, the optimal treatment combination was obtained for the air-abraded group sintered at 1450°C, followed by the air-abraded group sintered at 1550°C. Crack patterns analyses showed that the proportion of trans-granular fracture increased with sintering temperature. Conclusions: Annealing heat treatment is not recommended after any adjustments, as it does not improve the reliability of the material. Crack patterns and flexural strength are strongly influenced by the crystalline phase composition of the material. Sintering at 1600°C and 1650°C is not recommended due to the corresponding decrease in mechanical properties independently of treatment. Air-abrasion of zirconia sintered at 1450°C or 1550°C led to the best combination of high strength and reliability.

Dentistry has come a long way from its humble beginnings. Like all other healthcare specialties, dentistry has evolved through the years. The understanding of physiology of dental health and disease has evolved allowing us to treat dental diseases much more efficiently. However not all dental problems are fully understood. Diseases that affect the bone and soft tissue around teeth and dental implants, also known as “periodontal” and peri-implant” diseases respectively, have proven to be among the least understood and challenging dental diseases to treat. Recent advancements in microbiology and immunology have revealed that periodontal and peri implant disease have a plethora of interactions between the invading bacteria, the defensive human cells, and signaling micro molecules that control inflammation. Those interactions have opened up a new frontier for researchers in dentistry, microbiology, immunology, pharmacology and dental materials to understand these interactions and explore possible new treatments. Simvastatin is a commonly prescribed drug used to control blood cholesterol. Recent research has revealed that simvastatin also possesses potent anti-inflammatory properties, and research has shown that topical application simvastatin is effective at controlling inflammation around teeth with periodontitis. However it has not yet been tested around dental implants with peri-implant disease. Thus the purpose of the current study is to investigate the effect of topical simvastatin on implants with peri-implant inflammation

Thesis (MSD) --Boston University, Henry M. Goldman School of Dental Medicine, 2009 (Department of Periodontology and Oral Biology). / Includes bibliographic references: leaves 52-59. / Platelet-rich plasma (PRP) is a concentrated gel of platelets that contains several growth factors. Growth factors have been recognized as the part of PRP that play role in regeneration of the bone. It is not clear how these growth factors in PRP affect the bone regeneration. Resolvin El (RvEl; 5S,12R,18R-trihydroxyeicosapentaenoic acid) is an pro-resolving lipid mediator derived from omega-3 fatty acid eicosapentaenoic acid and shown to have potent effects on the resolution of inflammation. The purpose of this study was to analyze the action of PRP and RVEl on the proliferation and behavior of osteoblasts and osteoclasts in vitro. PRP was prepared from 14 healthy donors. Osteoblast cultures were from a cell line (Saos2) of osteosarcoma cells. Osteoclasts were differentiated from primary human peripheral blood monocytes. Osteoclastic morphology was studied and activity was analyzed via resorption on dentin discs using SEM. PRP and RVE 1 were added at different doses and time-points. Osteoblast function was analyzed by osteocalcin expression and release. Osteoclast activity was assessed by resorption and cathepsin K expression. PRP and RvEl comparably increased the osteoblastic activity and suppressed the osteoclast differentiation and function. These results suggest that multiple tools are available to reverse the inflammation and restore the lost bone architecture as a result of periodontal disease.

Dental caries is a common childhood disease and important health problem in the United States and throughout the world. Most studies that have assessed risk factors for dental caries focused on non-modifiable risk factors such as previous caries experience and socioeconomic status. It is also important to investigate modifiable risk factors that can be used in developing guidelines for risk assessment and prevention. The present dissertation assessed mainly the associations between dental caries and modifiable factors, including dietary factors, water fluoride levels and toothbrushing frequency in children, while adjusting for non-modifiable factors. Data were obtained from subjects who were participants in the Iowa Fluoride Study. Dietary data were collected using 3-day dietary diaries from 1.5 months to 8.5 years and detailed questionnaires from 9 years to 13 years. Dental caries examinations were conducted at about 5, 9 and 13 years of age. There are three main analyses. The first analysis assessed risk factors for a 4 group primary dentition caries experience variable: the caries-free (reference group), the d1, the d2+f, and the d1d2+f groups. The dietary consumption frequencies (from ages 3 to 5 years) for the children in the 4 caries groups were compared using multivariable multinomial regression analyses. Lower consumption frequency of milk at meals and greater consumption frequency of pre-sweetened cereal at meals significantly increased the likelihood of being in the d1 group. Greater consumption frequency of regular soda pop at snacks significantly increased the likelihood of being in the d1d2+f group. Greater consumption frequency of added sugars at snacks significantly increased chance to be in the d2+f group and the d1d2+f group. The second manuscript assessed risk factors for new mixed dentition cavitated caries determined based on surface-specific transitions from the primary to mixed dentition exams on 16 teeth using logistic regression analysis. Greater consumption frequency of processed starch at snacks significantly increased the likelihood of having new cavitated caries (p = 0.04 for the model excluding previous caries experience). The third manuscript used negative binomial regression with the Generalized Linear Mixed Models procedure to assess separately the longitudinal associations of 1) new non-cavitated caries and 2) new cavitated caries with modifiable risk factors. Surface-specific counts of new non-cavitated caries and cavitated caries at each of the primary, mixed and permanent dentition examinations were used as outcome variables. Greater consumption frequency of 100% juice was significantly associated with fewer non-cavitated and fewer cavitated caries surfaces. In this study, some factors were associated with caries at one age only, while others were associated with caries across childhood. Consumption of foods or beverages at meals generally decreased their cariogenicity. Previous caries experience is strongly associated with other independent variables in the regression models that examined risk factors for new cavitated caries. Thus modifiable factors that usually have weaker associations with caries might not be retained in the models due to collinearity issues. Future researchers are encouraged to present results both ways so that scientific communities can best interpret the complex results. Also, repeated measures analysis might be more appropriate for variables that are common in all age groups, such as toothbrushing frequency and fluoride exposures. More studies of the complex relationships between diet and caries are needed, including additional studies that place more emphasis on investigation of modifiable risk factors for both non-cavitated and cavitated caries.

The purpose of this study was to investigate factors related to Iowa dentists’ management of initial caries lesions for low, moderate and high-risk patients and their agreement with the International Caries Classification and Management System (ICCMS) Guidelines. A survey with three patient scenarios (low, moderate and high-risk) was electronically sent to 916 University of Iowa alumni dentists who were in active practice. Information on dentists’ demographics and practice characteristics were also collected in the survey. Descriptive statistics were conducted to profile the variables of interest. Bivariate analyses were performed to assess the factors associated with the management of initial caries lesions for each scenario. 138 (response rate=15%; male=83 and female=55) practicing dentists in Iowa completed the survey. Of these (mean age= 48.3±12.3 years, mean years of clinical practice= 21.4±12.5), 30.4% completed a formal post-graduate training program, and 35.5% were solo practitioners. Agreement with ICCMS guidelines regarding the management of initial caries lesions for low, moderate and high-risk scenarios was approximately 73%, 59%, and 51% respectively. Odds of having agreement with ICCMS in the low risk scenario for those who frequently dry the tooth was 3.56 times that of those who don’t dry the tooth for caries detection (p=0.0468). Odds of having agreement with ICCMS in the moderate risk for those who graduated < 20 years ago was 6 times that of those who graduated >20 years ago (p=0.0024). Odds of having agreement with ICCMS in the moderate risk scenario for those who practiced in public health setting was 14 times that of those who practiced in solo or group practices (p=0.0089) and for those who frequently used magnification was 2.9 times that of those who don’t use magnification (p=0.0225). Odds of having agreement with ICCMS in the high risk scenario for those who frequently performed CRA was 2 times that of those who don’t perform CRA (p=0.0262). The majority of Iowa dentists agreed with ICCMS guidelines in the non-surgical management of initial caries lesions regardless of patient risk level. Iowa dentists had the highest agreement with the ICCMS guidelines for low-risk scenario and agreement was associated with routinely drying teeth for caries detection. Evidence based decisions individualized for a patients’ risk status are essential for determining the best management of dental caries lesions.

Objective: The objective of this study was to measure and assess the implant education received by graduates from the University of Iowa College of Dentistry and Dental Clinics. This study measured the self-reported competency levels of dental practitioners with regards to providing and maintaining dental implants as treatment modalities to their patients. The study assessed dental graduates’ willingness to practice and perform dental implant procedures, including both surgical and prosthetic treatments. Additionally, the study identifies challenges that face practicing dentists treating patients with dental implants and identifies the preferred way practitioners seek future training after completing dental school. Methods: A 36-item electronic survey was created and distributed to 737 dentists who graduated from the University of Iowa College of Dentistry and Dental Clinics. Dentists’ demographics, practice characteristics, and detailed self-reported competency in implant dentistry were collected. Statistical analysis of the responses consisted of descriptive statistics and bivariate analysis, and nonparametric Wilcoxon rank-sum test and Spearman’s rank correlation test along with a chi-square test were used for detecting the differences, correlations and associations under different conditions. Results: 154 dentists completed the survey (21% response rate), while only 143 subjects who fulfilled the inclusion criteria were included for the statistical analysis. The survey consisted mostly of males (56.6%). The mean age of respondents was 34.2 years old with a mean practice time of 6.2 years. Of the responding dentists, 21.7% completed a postgraduate training program and 51% of the respondents were in group practice. 66% of the respondents practice in the Midwest region of the US and 71.3% of the respondents took continuing educational courses in implant dentistry and the mean cumulative hours of CE courses in implant dentistry was 33.8 hours. The mean average of implant restorations provided per year was 11.7 and the mean average of implant placements per year was 19.6. There was a significant correlation between cumulative hours of Continuing Education courses and number of implant units on average placed or restored. 64.3% of the dentists are not satisfied with the implant education given at the dental student level. 95.8% of the dentists reported that dental school training is not adequate to surgically place dental implants in their practice. Only 32.4% reported that dental school training was not adequate to restore dental implants in their practice. The preferred way to receive additional training about dental implants is short-term CE courses and workshop courses conducted by implant companies. 23.6% of the dentists reported they are competent at surgically placing dental implants in their practice. 79.1% reported they are competent at restoring dental implants in the dental office. Only 28.4% reported that they feel dental implants are more difficult than other dental treatments. Conclusions: Graduate dentists from the University of Iowa are not expected to be competent in all components of implant dentistry without further postgraduate training. Respondents stated that their dental school training in surgical placement of implants was inadequate. To build upon their dental school training, the two main preferred education pathways as reported by respondents were short-term continuing education courses and workshops courses conducted by implant companies. Within the parameters of this study, we can conclude the following: 1.Age, GPA, number of CE hours in dental implant therapy, specialty status, and time since graduation did not influence undergraduate education satisfaction in dental implant therapy. 2.There is a positive correlation between the number of CE course hours and the number of implant units restored or placed by general dentists. 3.Male dentists, those who practice in group practice settings, and those who have graduated six or more years ago reported a greater number of CE course hours in dental implant therapy. 4.Those who graduated with GPAs less than or equal to 3.4, general dentists, and those who enrolled in a high number of CE courses were more confident in restoring dental implants. 5.Those who graduated with a GPA greater than or equal to 3.5, specialist dentists, and those who enrolled in a high number of CE courses were more confident in surgically placing dental implants. 6.Males, general dentists, those who practice in a group practice setting, and those who graduated six years or more ago restored more implants on average per year. 7.Males, specialist dentists, those who practice outside the Midwest US, and those who graduated six years or more ago surgically place more implants on average per year.

Matrix metalloproteinases (MMP) are zinc- or calcium-dependent proteinases involved in the normal maintenance of the extracellular matrix. When elevated, MMPs degrade matrix components contributing to tissue destruction in infected periodontal sites. The objectives of this study were two-fold: first to assess the ability of Porphyromonas gingivalis hemagglutinin B (HagB) to induce MMP responses in human myeloid dendritic cells and second, to assess the effect of host defense peptide human β defensin 3 (HBD3) to regulate and attenuate the MMP response of HagB treated dendritic cells. HBD3 (0.2, 2.0, or 20.0 µM) was given to primary dendritic cells pre-, co-, or post-treatment to HagB (0.02 or 0.2 µM). At 16 hours, MMP concentrations were determined. There were no significant differences in concentrations for all 3 replications for MMP-2 and -13. There were few significant differences in some of the replications for MMP-3, -7, and -9. There were more pronounced differences in MMP-1, -10, and -12 expression, which were significantly influenced by both the concentration of HBD3 and the timing of administration. Chemokine and cytokine responses were inversely related to MMP production. While MMP responses decreased in a dose related manner, chemokine responses were increased. Concentrations of MIP-1α were high and there were no differences in response to 0.02 and 0.2 M HagB with or without 20.0 M HBD3. However, the MIP-1β and TNFα response to 0.2 M HagB were only attenuated. HagB induces the production of MMPs in dendritic cells and treatment of dendritic cells with HBD3 can alter the profile of HagB-induced MMPs. Such a finding may have importance in the pathogenesis of periodontal disease.

CAD/CAM technology had evolved extensively from the time when it was first used clinically in the 1980s. Today, CAD/CAM technology can be used to fabricate crowns, design and mill fixed partial denture frameworks, set teeth and fabricate complete dentures as well as to mill interim restorations. An extensive literature review found many research studies on the evaluation of the accuracy of the CAD/CAM ceramic crowns as compared to other ceramic crowns but little research had been done to evaluate the accuracy of interim restorations. This article describes the method in which CAD/CAM as well as conventional interim crowns were fabricated, cemented onto their dies, dye stained, thermocycled as well as sectioned with their marginal discrepancies investigated.