Browsing by Subject "Dental"
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Item Cost-effectiveness analysis of dental sealant using econometric modeling(2009-05) Ouyang, WeiDental sealants have been shown to be effective in reducing caries. Most believe sealants are still underused, particularly among children who need sealants the most. Because the caries prevalence continues to decline, and the disparities in children's dental heath and dental care still exist, more efficient sealant placement strategies should be implemented based on the scientific information from cost-effectiveness analysis (CEA) of dental sealant at the community level. Previous CEAs of sealant using observational datasets were unreliable because they did not address the self-selection problem. The objectives of this study are to examine the utilization of dental sealants and its determinants, evaluate the incremental effectiveness and expenditure associated with sealant placement after correcting the potential selection issue, and explore the differences in sealant's cost-effectiveness among subpopulations. This study mainly utilized enrollment data and encounter data from a large Health Maintenance Organization in Minnesota. The study sample included 3,700 children aged 6 to 17 years during 1997 to 2001 and were continuously enrolled for 5 years. They all had a caries risk assessment (CRA), which was conducted at the beginning of the observation period, and no prior caries record for their included first permanent molars (FPMs). The CRAs were classified into three scores: low, moderate and high risk. Information on the 64 dentists who participated in the study was linked to the encounter data to identify those who conducted CRAs. Outcome variables included discounted effectiveness, as measured by the duration of caries-free state (healthy months) of a FPM, and the discounted cost associated with caries treatments, within the study period. The key independent variables included demographic variables (e.g., age, gender, race), caries risk level, socio-economic status, sealant placement, and preventive care utilization. Bivariate analysis and logistic analysis were performed to examine the pattern of sealant utilization and identify the determinants affecting sealant placement decision. Econometric models including classic Tobit model, selectivity-corrected Tobit model, classic two-part model, and selectivity-corrected two-part model were used to examine the selection issue and obtain unbiased marginal effects of sealant on caries-free duration and caries-related treatment cost. The working experience of the dentists who conducted the initial CRAs was used as the instrumental variable. The bootstrap method was used to obtain standard errors and confidence intervals for the incremental cost-effectiveness ratios. Sensitivity analysis and subgroup analysis were performed. In this study, approximately 77% of the sample had one or more FPM sealed during the entry period, more than half of them had all four FPMs sealed. Children aged 6 to 8 were more likely to receive sealant than children aged 9 or older. Children at relatively high caries risk, as well as children who visited dentists for preventive care more than once a year, had greater odds of receiving sealants. Non-white children or those from families with low incomes or low education level were more likely to receive sealant. This study also identified some dentists' characteristics, such as age, gender, and working experience as the good predictors of sealant decision. After 5 years, the sealant group had more individuals (83.9%) and more FPMs (94.3%) that stayed healthy compared with the non-sealant group in which 83.1% of the sample individuals and 91.8% of FPMs stayed healthy. A sealed FPM was associated with $56.84 expenditure (initial sealant charge was $39.00) over 5 years, and an unsealed FPM was associated with $13.13 expenditure. The sample-average incremental cost-effectiveness ratio (ICER) was $38/caries-free month for each FPM. Based on the results from econometric models, sealants were associated with a lower probability of having any caries, longer caries-free duration, an increased probability of using any resource, and less resources consumption. The final ICER indicates that sealant cost $42.16 more than non-sealant treatment to get one more caries-free month for each FPM. The 95% CI was $22.64 to $85.40 per one more caries-free month for each FPM. Significant selection or endogeniety issue was not found in either the effectiveness or cost analysis based on the whole sample, but it existed when analyzing sealant effects among certain subgroup children. The results from subgroup analysis show that sealing children at high risk for caries appears to be highly cost effective. In contrast, sealing children at low risk for caries would be much less cost effective. Sealing the FPMs of infrequent utilizers of preventive care appears to be more cost effective than frequent utilizers of preventive care. There is no significant difference in ICERs between sealing younger children and sealing older children. In conclusion, sealant application is not always cost effective. A uniform and fixed sealant utilization goal may not be appropriate. Sealant application should be increased among the high risk populations, such as those with previous caries or low dental care utilizers, or those directly deemed at high caries risk by dentists. The caries risk assessment procedure can improve clinical decisions on sealant application and increase efficient sealant delivery.Item Evaluation of implant restoration retention on various custom abutment materials and surfaces(2018-05) McMillan, KalePurpose: Clinical use of cement-retained implant crowns requires selecting the appropriate abutment materials, surface characteristics, and cement type, based on finding the right balance between the desired level of retention form and the potential need for retrievability for each patient case. The purpose of this study was to evaluate the forces needed to vertically displace a cement-retained implant crown, using a provisional cement and five different combinations of abutment materials and surface characteristics. Material & Methods: A clinical master cast with an implant analog in the maxillary right central incisor site was fabricated and facilitated the design and manufacturing of 25 implant custom abutments planned for cement-retained restorations. Although all 25 implant custom abutments were designed to be identical in contour, each group of five abutments was fabricated from different materials or had different surface characteristics. The five different implant abutment groups were titanium smooth surface (Ts), titanium with retentive grooves (Tr), titanium with a nitride coating and smooth surface (Gs), titanium with a nitride coating and retentive grooves (Gr), and zirconia (Z). A total of 25 lithium disilicate crowns were fabricated and each crown was cemented to its corresponding abutment with non-eugenol temporary resin cement. With the use of a universal testing machine, the maximum tensile strength needed to dislodge the crown from the abutment was recorded and evaluated. Results: The mean tensile force needed to decement the lithium disilicate crowns within each implant abutment group was 31.58 N for titanium smooth surface (Ts), 29.29 N for titanium with retentive grooves (Tr), 32.90 N for titanium with nitride coating with smooth surface (Gs), 28.75 N for the titanium with nitride coating with retentive grooves (Gr), and 139.49 N for zirconia (Z). The titanium abutment groups did not differ significantly (P=.92); however, the zirconia abutment group required a statistically significant higher tensile force to decement the lithium disilicate crowns cemented with non-eugenol temporary resin cement compared to the titanium abutment groups (P<.05) Conclusion: Surface characteristics of the titanium implant abutments, including retentive grooves and nitride coating, did not increase the tensile force required to decement the crowns compared to a smooth titanium surface. The fabrication of zirconia abutments has the potential to generate discrepancies in the size and shape of the zirconia abutments, especially compared to the milled titanium abutments. The possible discrepencies in the zirconia abutments, including larger surface areas and need for nonstandardized crowns to fit the zirconia abutments may contribute more significantly to the increased retention compared to the interaction of the abutment material and provisional cement.Item Investigating the Cytocompatibility of a Novel Flipped Ester Group Design Polymer Composites against Oral Keratinocytes(2022-05-09) Kumar, Dhiraj; Bolskar, Robert D; Mutreja, Isha; Jones, Robert S; rsjones@umn.edu; Jones, Robert S; Minnesota Dental Research Center for Biomaterials and Biomechanics, Isha Mutreja; B-A-M (Biofilm-Apatite-Microbiome) Lab, Robert S Jones, Dhiraj Kumar; TDA Research Inc, Robert D BolskarThe methacrylate based polymeric materials have been widely used in dentistry because of the ease in tuning the physico-mechanical properties along with their ability to polymerize at room temperature in a period of seconds without causing deleterious exothermal effects. However, these materials are susceptible to hydrolysis of functional ester groups in the polymer backbone which prompted the development of a novel designer polymer with ester groups present in the side chain instead of the polymer backbone. Previously we have compared the physico-mechanical and stability profile of the new polymer with traditional EGDMA using accelerated aging, esterase, and bacterial incubation models. Another important parameter for polymer design in biological systems, such as use in dentistry, is polymer biocompatibility. The goal of this pilot investigation was to assess the cytocompatibility of novel design polymer EGEMA compared to EGDMA, a diluting agent in dental formulations, and a commercially available formulation Helioseal® (Ivoclar Vivodent). Material discs of the EGEMA, EGDMA, and Helioseal® were test in the presence of oral keratinocytes (TERT-2/OKF-6). After assessing oral keratinocytes cellular metabolic activity and cell morphology, the investigation suggested EGEMA and EGDMA showed comparable cytocompatibility that was statistical more favorable than Helioseal®.Item A Novel Methacrylate Derivative Polymer That Resists Bacterial Cell-Mediated Biodegradation Data Sharing Archive(2021-11-22) Kumar, Dhiraj; Ghose, Debarati; Mutreja, Isha; Bolskar, Robert; Jones, Robert S; rsjones@umn.edu; Jones, Robert S; B-A-M (Biofilm-Apatite-Microbiome) Lab, Robert S Jones DDS PhD, School of Dentistry, University of Minnesota; TDA Research, Inc.We studied biodegradation resistance of a custom synthesized (by TDA Research Inc) novel ethylene glycol ethyl methacrylate (EGEMA) with ester bond linkages that are external to the central polymer backbone when polymerized. Experiments were designed to compare degradation resistance with Ethylene glycol dimethacrylate (EGDMA) with internal ester bond linkages. The data has been published in an article titled "A Novel Methacrylate Derivative Polymer That Resists Bacterial Cell-Mediated Biodegradation" in the Journal of Biomedical Materials Research: Part B - Applied Biomaterials. The data in this record supports the figures in the published manuscript.