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Browsing by Author "Diefenderfer, Kim E."
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Item Ability of Caries Detection Methods to Determine Caries Lesion Activity(2019-12) Aldawood, Fatma; Ando, Masatoshi; Hara, Anderson T.; Diefenderfer, Kim E.Background: Non-cavitated caries lesions form due to acid diffusion and demineralization of enamel subsurface with an intact surface layer (SL). Caries lesions progress when the outcome of demineralization and remineralization processes over time is net mineral loss. Lesions that continue to demineralize are called active, while those that display no evidence of further demineralization are called inactive. Micro-computed-tomography (µCT) analysis provides objective non-destructive measurements of the thickness of the surface layer (SL) and severity of caries lesions. Aims: 1) To investigate if visual/tactile suspected active non-cavitated early white spot lesions present a thinner surface layer than inactive ones; 2) To investigate if there is an association between the thickness of the surface layer (SLT) and caries activity, as determined by QLF during dehydration (△QD); 3) To determine lesion severity by comparing lesion volume and maximum depth correlation with △Q value at 15 s from QLF during dehydration. Materials and Methods: Thirty extracted human premolars exhibiting non-cavitated approximal white spot early lesions stored in 0.1.-percent thymol/4C and treated with 5.0-percent NaOCl/30 min were included in the study. Fifteen active and 15 inactive lesions were determined by visual/tactile examinations by consensus of two experienced examiners. Roughness measurements (Ra) were acquired using non-contact optical profilometry. Two-dimensional minimum (2D-min), maximum (2D-max), average (2D-avg) SL and three-dimensional (3D) analyses, volume and depth of lesions were determined from µCT image analysis. A series of fluorescence images were acquired at baseline (hydrated), at 1 s, at 5 s, at 10 s and at 15 s by QLF. During image acquisition, surfaces were dehydrated with continuous-compressed-air. △Q and △Q/s (△QD) were calculated. Data were analyzed using two-sample t-tests and Pearson correlation coefficients (p < 0.05). Results: Surface roughness of active and inactive lesions was not significantly different (p > 0.08). Overall lesion volume and depth in dentin were significantly larger in active lesions (p = 0.022, p = 0.009). SL thickness of active and inactive lesions was not significantly different (2D = 0.121, 3D = 0.080, 2D-avg = 0.446, 2D-min = 0.197, 2D-max = 0.122). △QD at 1s was significantly larger for active lesions (p = 0.046). ΔQ at 15 s of dehydration had a moderate positive association with lesion volume (r = 0.56). △QD had a weak negative association with SL thickness (2D-avg) and (2D-min). Conclusions: 1) Active and inactive non-cavitated lesions show no difference in SL thickness; 2) QLF during dehydration (△QD) does not correlate well with SL thickness; 3) ΔQ at 15 s of dehydration correlates moderately well with lesion volume and is consistent with caries activity assessed by visual/tactile examination.Item Comparison of Internal Adaptation of Bulk-fill and Increment-fill Resin Composite Materials(2019-01) Alqudaihi, Fatema Sabri; Cook, N. Blaine; Diefenderfer, Kim E.; Bottino, Marco C.; Platt, Jeffrey A.; Cariology, Operative Dentistry and Dental Public Health, School of DentistryObjectives: To evaluate 1) the internal adaptation of a light-activated incremental-fill and bulk-fill resin-based composite (RBC) materials by measuring the gap between the restorative material and the tooth structure and 2) the aging effect on internal adaptation. Methods and Materials: Seventy teeth with class I cavity preparations were randomly distributed into five groups; four groups were restored with bulk-fill RBCs: Tetric EvoCeram Bulk Fill (TEC), SonicFill (SF), QuiXX Posterior Restorative (QX), and X-tra fil (XF); the fifth group was restored with incremental-fill Filtek Supreme Ultra Universal Restorative (FSU). One-half of the specimens of each group were thermocycled. Each tooth was sectioned, digital images were recorded, and the dimensions of any existing gaps were measured. Data were analyzed using analysis of variance (α=0.05). Results: FSU had the smallest gap measurement values compared with the bulk-fill materials except QX and TEC (p≤0.008). FSU had the smallest sum of all gap category values compared with the bulk-fill materials, except QX (p≤0.021). The highest gap incidence and size values were found at the composite/adhesive interface. All aged groups had greater gap values in regard to the gap measurement and the sum of all gap categories compared with non-aged groups. Significance: The incrementally placed material FSU had the highest internal adaptation to the cavity surface, while the four bulk-fill materials showed varied results. Thermocycling influenced the existing gap area magnitudes. The findings suggest that the incremental-fill technique produces better internal adaptation than the bulk-fill technique.Item A Direct Refractory Die Technique for Cast Gold Restorations(2017-03) Smith, Cleveland T.; Diefenderfer, Kim E.; Cariology, Operative Dentistry and Dental Public Health, School of DentistryFabricating accurate cast gold restorations can be challenging for both clinicians and laboratory technicians. Removing the wax pattern from the master die often distorts the pattern, which, in turn, compromises the overall fit and marginal adaptation of the casting. This article demonstrates a laboratory technique in which the final restoration is cast directly on the refractory die without removing the wax pattern. Thus, distortion of the wax pattern is avoided, enabling the production of superbly fitting gold castings for both intracoronal and extracoronal restorations. Used by permission. © Operative Dentistry, Inc. Transmission or reproduction of protected items beyond that allowed by fair use requires the written permission of Operative Dentistry, IncItem Influence of curing-light beam profile non-uniformity on degree of conversion and micro-flexural strength of resin-matrix composite(2016-10-05) Eshmawi, Yousef Tariq; Platt, Jeffrey A.; Hara, Anderson T.; Diefenderfer, Kim E.; Cook, Norman B.Background. Beam profile non-uniformity of light-curing units (LCUs) may result in suboptimal properties of resin-matrix composite (RMC) restorations. Objectives: The objective of this study was to evaluate the effect of curing-light beam profile of multiple light curing units (LCUs) on the degree of conversion (DC) and micro-flexural strength (μ-flexural strength) of RMC. Methods: Forty-five nano-filled hybrid RMC (Tetric EvoCeram, Ivoclar Vivadent, Amherst, NY) specimens were fabricated. Quartz tungsten halogen (QTH) (Optilux 401) (O), multiple emission peak (VALO Cordless) (V) and single emission peak (Demi Ultra) (DU) light-emitting-diode (LED) LCUs were investigated at different light-curing locations (LCLs): 1) the center of the LCU tip; 2) 1.5 mm to the left of the center of the LCU tip; and 3) 1.5 mm to the right of the center of the LCU tip. Specimens were stored wet in deionized water at 37C for 24 hours. The DC was measured on top and bottom surfaces using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Micro-flexural strength testing was performed using a universal mechanical testing machine at crosshead speed of 1 mm/min. Multi-factorial ANOVAs were used to analyze the data (α = 0.05). Results: All LCUs exhibited significant differences in DC between top and bottom surfaces at the different LCLs. Micro-flexural strength varied with LCL for DU. Conclusions: The non-uniform curing-light beam profile could have a significant effect on μ-flexural strength and DC on top and bottom surfaces of RMC specimens cured at different LCLs.Item Longevity of Crown Margin Repair Using Glass Ionomer: A Retrospective Study(International Association for Dental Research, 2020) Watson, Justin; Tang, Qing; Patel, Jay; Diefenderfer, Kim E.; Thyvalikakath, Thankam; Cook, N. BlaineObjectives: Repair of crown margins may extend the functional life of existing crowns. However, the longevity of such treatment is unknown. This study determined the survival time of crown margin repairs (CMR) with glass-ionomer (GI) and resin-modified glass-ionomer cements. Methods: We queried axiUm (Exan Group, Coquitlam, BC, Canada) database for permanent teeth that underwent CMR in the Graduate Operative Dentistry Clinic, Indiana University School of Dentistry (IUSD), Indianapolis, Ind., USA, from January 1, 2006 through January 1, 2018. Since there is no CDT code for the CMR procedure, CDT codes for resin-composite and GI restorations (D23XX) were queried; these patients also had treatment notes that indicated CMR. The final data set included patient ID, birth date, gender, dates of treatments, CDT codes, tooth type, tooth surface and existing findings. Two examiners developed guidelines for record review and manually reviewed the clinical notes of patient records to confirm CMR. Only records that were confirmed with the presence of CMR were retained in the final dataset for survival analysis. Survival time was calculated by Kaplan-Meier statistics and a Cox Proportional Hazards model was performed to assess the influence of selected variables (p < 0.05). Results: 214 teeth (115 patients) with CMR were evaluated. Patient average age was 69.4 11.7 years old. Posterior teeth accounted for 78.5 percent (n = 168) of teeth treated. CMRs using GI had a projected 5-year survival rate of 62.9 percent (K-M Analysis) and an 8.9 percent annual failure rate. Cox Proportional Hazards Regression analysis revealed that none of the factors examined (age, gender, tooth type) affected time to failure. Conclusion: CMRs may extend the longevity of crowns with defective margins. Larger EHR studies or case control studies are needed to investigate other variables, such as the caries risk status or the severity of defects that may affect the survival rate of CMR.Item Longevity of Crown Margin Repairs Using Glass Ionomer: A Retrospective Study(2020) Watson, Justin I.; Cook, N. Blaine; Thyvalikakath, Thankam; Diefenderfer, Kim E.; Capin, OrianaObjectives: Repair of crown margins may extend the functional life of existing crowns. However, the longevity of such treatment is unknown. This study determined the survival time of crown margin repairs (CMR) with glass-ionomer (GI) and resin-modified glass-ionomer cements. Methods: We queried axiUm (Exan Group, Coquitlam, BC, Canada) database for permanent teeth that underwent CMR in the Graduate Operative Dentistry Clinic, Indiana University School of Dentistry (IUSD), Indianapolis, Ind., USA, from January 1, 2006 through January 1, 2018. Since there is no CDT code for the CMR procedure, CDT codes for resin-composite and GI restorations (D23XX) were queried; these patients also had treatment notes that indicated CMR. The final data set included patient ID, birth date, gender, dates of treatments, CDT codes, tooth type, tooth surface and existing findings. Two examiners developed guidelines for record review and manually reviewed the clinical notes of patient records to confirm CMR. Only records that were confirmed with the presence of CMR were retained in the final dataset for survival analysis. Survival time was calculated by Kaplan-Meier statistics and a Cox Proportional Hazards model was performed to assess the influence of selected variables (p < 0.05). Results: 214 teeth (115 patients) with CMR were evaluated. Patient average age was 69.4 11.7 years old. Posterior teeth accounted for 78.5 percent (n = 168) of teeth treated. CMRs using GI had a projected 5-year survival rate of 62.9 percent (K-M Analysis) and an 8.9 percent annual failure rate. Cox Proportional Hazards Regression analysis revealed that none of the factors examined (age, gender, tooth type) affected time to failure. Conclusion: CMRs may extend the longevity of crowns with defective margins. Larger EHR studies or case control studies are needed to investigate other variables, such as the caries risk status or the severity of defects that may affect the survival rate of CMRs.Item Shear Bond Strengths Of A Two-Step Self-Etch Adhesive And A Three-Step Etch-And-Rinse Adhesive In Artificial Dentin Caries Lesions Of Various Depths: An In Vitro Study(2024-07) Buechele, Ryan W.; Cook, Norman B.; Diefenderfer, Kim E.; Capin, Orian R; Sochacki, Sabrina F.; Strother , James M.Background: Minimally invasive caries management philosophy advocates leaving carious dentin as a substrate for adhesive bonding. However, the performance of current resin adhesives in incompletely excavated caries lesions is unknown. Understanding the limitations of bonding to carious dentin is critical for the restoring clinician. Objective: To compare the shear bond strengths of a two-step self-etch adhesive and a three-step etch-and-rinse adhesive to moderate and severe artificial dentin caries. Methods: 96 bovine incisors were prepared and assigned to experimental groups of moderate or severe artificial dentin caries lesions or control groups (sound dentin). Specimens were randomly assigned to a two-step self-etch (Clearfil SE Bond 2) or three-step etch-and-rinse (OptiBond FL) adhesive for bonding to a nanohybrid composite resin. TMR analysis determined lesion depth. Specimens were stored for 30 days in Millipore water (5oC), shear bond strengths were measured, and failure modes observed. Two-way ANOVA with interactions evaluated the effects of adhesive type and demineralization severity on shear bond strength. Failure modes were compared using ordinal logistic regression. A two-sided 5% significance level was used for all tests. Results: Clearfil SE performed significantly better than Optibond FL in both moderate and severe lesions. Both adhesives performed adequately on sound dentin, but poorly in severe lesions. For OptiBond FL, bond strengths were lowest in moderate lesions; failures were predominantly mixed or cohesive within composite resin in both moderate and severe lesions, as well as in sound dentin specimens. For Clearfil SE, bond strengths were lowest in severe lesions; failures were predominantly adhesive in moderate lesions, cohesive within composite resin in severe lesions, and mixed adhesive/cohesive in sound dentin specimens. Discussion: Bonding to demineralized dentin was highly variable for both adhesives. Bonding to sound dentin yielded higher bond strengths. Conclusions: A three-step etch-and-rinse adhesive did not perform better than a two-step self-etch adhesive in this study. A self-etch adhesive may be the better choice when bonding to demineralized dentin. Either adhesive may be acceptable when bonding to sound dentin.