Browsing by Subject "Dental Enamel"
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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 A comparison of neodymium: Yttrium, aluminum, garnet laser effects between primary and permanent enamel of dissaciated teeth(1995) Tleel, Nora Najeeb, 1967-; Dean, Jeffrey A.; Sanders, Brian J.; Schemehorn, Bruce Richard, 1950-; Pruesz, Gerald C.; Avery, David R.While advances in lasers for soft tissue applications have drastically increased its usage in dentistry, laser use for hard tissue still needs development. This study was conducted to determine the difference between permanent and primary enamel after their exposure to the Nd:YAG laser. Four parameters were studied: Surface topography, acid resistance, surface hardness and caries-like lesion depth creation. Differences between lased primary and permanent teeth were seen in two parameters. Calcium disassociation during acid attack was significantly higher for lased primary enamel (p=0.0126), and lased primary enamel became softer while permanent enamel became harder (p=0.0001). While this study adds to the body of knowledge related to hard tissue laser use, further evaluation and research is needed prior to the routine use of the laser on primary enamel.Item Effect of Adherent Contour on Orthodontic Tensile Bond Strength(2001) Alvarez, Edwin; Katona, Thomas R.; Baldwin, James J.; Hohlt, William F.; Moore, B. Keith; Shanks, James C.Many factors may affect orthodontic bond strength study results. An important variant to consider is the bonding surface contour. Contour alters the proximity of adherent surfaces, the surface area available for adhesion, and the stress distribution. It was the purpose of this study to determine if bracket base or enamel contour affect in vitro bond strengths. Orthos Mini-Diamond (ORMCO Corp.) .0 018" slot central incisor brackets with flattened or unaltered curved bases were bonded (System 1 + self cure resin cement by ORMCO, Corp.) to unaltered and flattened bovine central incisors. Bond strengths were determined by debonding on a Bionix 858 (MTS System Corp.) testing machine. The results showed that unaltered bracket bases bonded on unaltered enamel surfaces (the closest approximation to a clinical situation) had the significantly (p< 0.0002) lowest tensile bond strength among the three combinations. The adhesive remnant index evaluation demonstrated that unaltered bracket base/ unaltered enamel surface (Group II) had significantly higher ARI (less adhesive remaining on enamel) than any of the other groups. A negative correlation between ARI scores and mean bond strength was found. There was not a significant difference between flattened bracket base / flattened enamel surface (Group I) and unaltered bracket base/ flattened enamel surface. The results suggest that the surface convexity and texture of enamel are important variables that can affect bond strength tests results. Standardization of testing protocols and control of the different variables that can affect bond strength are important factors in the testing of orthodontic brackets.Item The Effect of Silver Diamine Fluoride on Caries Lesion Remineralization as a Function of Lesion Baseline Mineral Distribution(2022) AlMady, Fahad; Lippert, Frank; Hara, Anderson; Al Dehailan, Laila; Capin, OrianaPurpose: The primary objective of this laboratory study was to investigate whether the ability of SDF to remineralize caries lesion is modulated by their baseline mineral distribution. The exploratory objective was to determine whether the staining caused by SDF is modulated by lesion mineral distribution. Materials and methods: This in vitro study utilized bovine permanent enamel specimens. SDF was compared to the clinical reference standard, 5% sodium fluoride varnish (FV), and deionized water (DIW) was the negative control. By utilizing three lesion creation protocols (methylcellulose [MeC], hydroxyethylcellulose [HEC], Carbopol [C907]), artificial caries lesions with different mineral distributions (n=20 per subgroup) were created in the enamel specimens Interventions were applied and the lesions remineralized using artificial saliva. Changes in mineral loss, lesion depth, mineral density of the surface zone, and lesion mineral distribution were determined using transverse microradiography. Throughout the study, color of the lesion and changes thereof were measured using a spectrophotometer. Data were analyzed by using two-way ANOVA. Pair-wise comparisons were performed using Fisher’s Protected Least Significant Differences to control the overall significance level at 5%. Results: For changes in mineral loss, DIW in MeC showed significantly greater change (more remineralization) than both SDF (p<0.01) and FV (p=0.01), which were not different from one another (p=0.13). There were no statistically significant differences between SDF and FV in the other lesions (C907 – p=0.18; HEC – p=0.56). For changes in lesion depth, there was no statistically significant interaction between study factors lesion protocol and treatments (p=0.23) as well as the individual factors lesion protocols (p=0.08) and treatments (p=0.82). For changes in surface zone mineral density, SDF showed significant change in mineral density compared to FV (p=0.02); however, SDF was not different from with DIW (p=0.25). For lesion mineral distribution, MeC exhibited the greater mineral loss in the lesion body and lowest mineral density at the surface zone. HEC lesions were the deepest but exhibited modest differences in mineral loss between the lesion body and the surface zone. C907 lesions were somewhat between MeC and HEC. SDF in MeC had the highest mineral gain in the surface zone, while DIW resulted in the highest mineral gain in the lesion body. SDF in HEC showed the highest mineral gain in the surface area compared to FV and DIW, with all treatments resulting in the largest mineral gain to a similar extent in the lesion body. In C907, SDF showed the most mineral gain in the lesion body compared to DIW and FV, while differences in the surface zone between treatments were less pronounced. For color changes post intervention, SDF showed more darkening in C907 and HEC lesions compared to MeC (p<0.01) and compared to FV and DIW. For post remineralization, SDF treated C907 lesions became significantly whiter (p<0.01) compared to SDF in MeC and HEC which continued to get darker. Conclusion: SDF did exhibit different remineralization abilities and behaviors and the modulation was based on lesion baseline mineral distribution. Staining resulting from SDF treatment varied significantly based on lesion mineral distribution.Item Fluoridated Orthodontic Adhesives' Effect on Enamel Fluoride Content and Demineralization(1995) Lampros, Penny Lynn; Moore, B. Keith; Arbuckle, Gordon R.; Katona, Thomas R.; Shanks, James C.; Swartz, Marjorie L.; Zitterbart, Paul A.Orthodontists are concerned about the high incidence of demineralization and decalcification around appliances. The orthodontic appliances diminish the self-cleansing mechanisms of the oral cavity, and in essence, act as traps for plaque and other debris that often lead to decalcification of the surrounding enamel. Fluoride containing dental restorative cements have been shown to reduce the incidence of secondary caries. The purpose of this study was to compare two fluoride containing orthodontic resin adhesives (a commercial, Phase II F, and an Experimental Adhesive) with a commercial nonfluoridated resin adhesive (Phase II). The resins were compared with respect to fluoride release in water over a 30 day period, hardness, and their effects on enamel fluoride content and enamel demineralization. Resin discs were made from the two fluoridated adhesives and placed in glass distilled water. Fluoride ion concentrations of the water were measured daily, and the accumulated concentrations were calculated for 30 days. Hardness discs were constructed from each adhesive, and Knoop hardness was measured after one hour, one day and one week. Finally, orthodontic brackets were bonded to bovine enamel discs, and two weeks after cementation of the brackets, the specimens were demineralized, and the adjacent enamel was biopsied for fluoride content. Those same specimens were sectioned longitudinally through the bracket and then stained with Rhodamin B. Areas of demineralization extending 500 μm from the bracket edge were measured by a confocal microscope. Depth of demineralization was measured at 250 μm intervals up to 1000 μm. The Experimental Adhesive released fluoride at a significantly higher rate over 30 days than did Phase 11 F. None of the three materials demonstrated any dramatic change in hardness after one week in water. Enamel exposed to the Experimental Adhesive had the highest fluoride content followed by that associated with Phase II F. The lowest fluoride content was found in the nonfluoridated Phase 11 adhesive. The extent of enamel demineralization, in area and depth, was inversely related to the fluoride pattern, although these differences were not statistically significant. A definite trend was noted for increased fluoride content and decreased demineralization of enamel due to increased fluoride released by the Experimental Adhesive.Item The Impact of Mouthrinses on the Efficacy of Fluoride Dentifrices in Preventing Enamel and Dentin Erosion/ Abrasion(2018) Albeshir, Ebtehal; Lippert, Frank; Cook, Norman B.; Hara, AndersonObjective: Toothbrushing with fluoride toothpaste followed by rinsing with mouthwash is a routine procedure to maintain good oral hygiene. It is unknown to what extent these rinses can modulate the effect of fluoride in its ability to prevent erosion/abrasion.The aim of this in-vitro study was to investigate and compare the impact of chlorhexidine (CHX), essential oils (EO) and cetylpyridinium chloride (CPC) mouthrinses on erosive tooth wear protection afforded by conventional fluoride toothpastes. Materials and Methods: The following experimental factors were considered: five rinses: CHX, EO, CPC, a fluoride rinse, and deionized water, two fluoride toothpastes: stannous fluoride (SnF2) or sodium fluoride (NaF) and two models: (erosion/ erosion+abrasion). Slabs of bovine enamel and dentin were prepared and embedded in resin blocks and generated 10 enamel and dentin testing groups (n = 8). UPVC tapes were placed on the sides of each slab leaving 1mm area exposed in the center. The blocks were subjected to a five-day cycling model. Then, the blocks were placed in a brushing machine and exposed to fluoride toothpaste slurry (one side was brushed and the other wasn’t). The blocks were then exposed to rinse treatments. Artificial saliva was used to remineralize the specimens after erosions and treatment challenges, and as storage media. After the fifth day of cycling, surface loss (in micrometers) was determined by profilometer. Data were analyzed using ANOVA (α = 0.05). Results: There was no interaction among the three factors (type of toothpaste, mouthrinse and abrasion or not (dentin p = 0.0520, enamel p = 0.4720). There were no significant two-way interactions as SL was only affected by toothpaste and mouthrinse. NaF caused less SL than SnF2 (4.60 vs. 5.83 μm; p < 0.0001) in dentin, whereas the opposite was found in enamel (5.20 vs. 3.56 μm; p < 0.0001). Toothbrushing abrasion caused comparatively more SL in enamel (6.53 vs. 2.23 μm; p < 0.0001) than in dentin (6.06 vs. 4.38 μm; p < 0.0001). None of the tested mouthrinses affected SL. Conclusion: Commonly used mouthrinses containing antimicrobial agents or additional fluoride, do not impair the erosion/abrasion protection afforded by fluoride toothpastes. Tested SnF2 dentifrice offered greater protection against enamel surface loss and NaF dentifrices showed more protection for the dentin surface. Clinical relevance: The understanding of the interaction between commonly used rinses and fluoride dentifrices will help dentists provide better recommendations to patients with erosive lesions.Item The influence of baseline hardness and chemical composition on enamel demineralization and subsequent remineralization(2017-05-09) Alkattan, Rana; Ando, Masatoshi; Lippert, Frank; Cook, Norman BlaineBACKGROUND Several studies have reported that harder enamel with higher contents of calcium (Ca), phosphorus (P) and fluorine (F) coupled with lower contents of carbonate (C), magnesium (Mg) and nitrate (N) was found to be more resistant to demineralization. Additionally, the hardness of dental enamel was found to have a strong correlation with its chemical content. However, yet to be established is the relation between the physical and chemical structure of enamel and its response to de- and remineralizing conditions. OBJECTIVES The aims of this laboratory study were: 1) To investigate the hardness and chemical content of sound enamel and their influence on demineralization; 2) To investigate these properties in demineralized enamel and their influence on remineralization; and 3) To investigate these properties in sound enamel and their influence on remineralization. MATERIALS AND METHODS Incipient subsurface caries lesions were created in 94 bovine enamel specimens using Carbopol C907 using three demineralization times. The specimens were then pH-cycled and treated using either 367 ppm F sodium fluoride or a placebo. Knoop surface microhardness (SMH), Energy dispersive X-ray spectroscopy (EDS) and Transverse microradiography (TMR) were performed on the specimens at all stages and compared between them. TMR variables included integrated mineral loss (ΔZ), Lesion depth (L) and maximum mineral density of the surface zone (SZmax). Data were analyzed using three- and four-way ANOVA and Pearson correlation coefficients were calculated. RESULTS SMH, ΔZ, L and SZmax were significantly different among stages, demineralization times and treatment. The weight% of F at the surface was significantly affected by treatment, irrespective of demineralization time. A statistically significant moderate correlation was found between SZmax and ΔZ and SZmax and L after pH cycling. SMH also correlated weakly to moderately with TMR data. CONCLUSIONS SMH and SZmax decreased while ΔZ and L increased with increased demineralization time. Both fluoride and non-fluoride specimens were able to remineralize, which emphasizes the role of saliva in mineralization. The Ca:P ratio remained stable at various stages, indicating the stoichiometric dissolution and redeposition of minerals. The greatest deposition of F was at the surface and its increase led to an increase in SMH and SZmax. SMH values showed that harder specimens at baseline and after demineralization remained hard after demineralization and pH-cycling, respectively, although this correlation was weak. Additionally, harder lesions showed less L and ΔZ and greater SZmax. RELEVANCE This in-vitro study will help better understand the caries process and the impact of physical and chemical characteristics of enamel on de- and remineralization challenges.Item Investigations of the anti-caries potential of fluoride varnishes(2015-11-12) Al Dehailan, Laila Adel; Martinez-Mier, Esperanza Angeles; Lippert, Frank; Soto-Rojas, Armando E.; González-Cabezas, Carlos; Stelzner, SarahThe majority of currently marketed fluoride varnishes (FV) have not been evaluated for their effectiveness in preventing dental caries. Fundamental research on FVs and how different formulations affect adherence to teeth, fluoride release into saliva and uptake by teeth is virtually non-existent. The objective of this work was to investigate the anti-caries potential, measured as fluoride release into saliva, change in surface microhardness of early enamel caries lesions, and enamel fluoride uptake, of multiple commercially available FVs. We have found that FVs differed in their release characteristics, rehardening capability, and ability to deliver fluoride to demineralized lesions. In addition to our in vitro work, we have conducted a clinical study that aimed to compare saliva and plaque fluid fluoride concentrations following the application of three commercially available FV treatments at predetermined post application time points. We also investigated the change in fluoride concentration in saliva and plaque fluid fluoride from baseline to each post application predetermined time point. We found that FVs varied in their release of fluoride into saliva and plaque fluid but shared common trends in release characteristics. The outcomes of our in vitro and in vivo investigations demonstrate a great variation in anti-caries potential of FVs. This may be attributed to different compositions and physical properties of the tested FVs.Item Longitudinal In Vitro Effects of Silver Diamine Fluoride on Early Enamel Caries Lesions(2020) Thompson Alcorn, Alice-Anne; Lippert, Frank; Al Dehailan, Laila; Cook, N. BlaineObjective: This study aimed to evaluate surface microhardness changes in early, incipient, non-cavitated white-spot, enamel caries lesions treated with silver diamine fluoride (SDF) longitudinally. The utilization of silver nitrate and potassium fluoride test groups served as additional controls to assist in evaluating if the remineralization effects were due to the silver or fluoride component in SDF. Hypotheses: 1. SDF treatment will result in increased surface microhardness of early, incipient, non-cavitated white-spot, enamel caries lesions compared to all other tested interventions. 2. Specimen storage for 2-weeks in artificial saliva will result in greater surface rehardening in lesions treated with SDF compared to other tested interventions. Design: This laboratory study had 5 intervention groups (SDF, silver nitrate (AgNO3), potassium fluoride (KF), 5.0-percent sodium fluoride varnish (FV), deionized water (DI)) × 2-time intervals after intervention (immediate & delayed pH-cycling), resulting in 10 groups (n = 18). Early, incipient, non-cavitated white-spot, enamel caries lesions were created in bovine enamel and extent of demineralization was determined using Vickers surface microhardness (VHNlesion). Intervention treatments were applied. Half the specimens from each group underwent immediate 5-day pH-cycling and half were stored in an incubator with artificial saliva for two weeks before undergoing 5-day pH-cycling. After pH-cycling, lesion hardness was evaluated using VHNpost. Specimens were then exposed to a second demineralization challenge and lesion softening was evaluated using VHNsecdem. Surface rehardening was calculated: ΔVHN =VHNpost - VHNlesion. Surface softening was calculated: ΔVHNsecdem =VHNsecdem – VHNpost. Data was analyzed using two-way ANOVA. Results: Immediately cycled, SDF had significantly (p < .0001) greater remineralization than DI, AgNO3, and FV. All delayed cycling groups had significantly (p < .0001) greater remineralization than FV. Significantly greater remineralization was noted in delayed AgNO3 (p < .0001), DI (p = .0003), and FV (p = .0006) compared to immediately cycled. After the second demineralization challenge, FV had significantly less surface softening than AgNO3 (p = 0.0002), DI (p = 0.0003), KF (p = 0.0225), and SDF (p = 0.0388) intervention groups. No significant difference was found between the pH-cycle timings. Conclusion: Based on our findings, FV maybe better suitable than SDF to treat early, incipient, non-cavitated white-spot, enamel caries lesions. Longitudinally, SDF exhibited greater remineralization than both FV and DI groups, though not statistically significant. However, upon a second demineralization challenge, FV significantly outperformed SDF in preventing surface softening.Item Monitoring of sound and carious surfaces under sealants over 44 months(SAGE Publications, 2014-11) Fontana, M.; Platt, J. A.; Eckert, G. J.; González-Cabezas, C.; Yoder, K.; Zero, D. T.; Ando, M.; Soto-Rojas, A. E.; Peters, M. C.; Department of Restorative Dentistry, IU School of DentistryAlthough there is strong evidence for the effectiveness of sealants, one major barrier in sealant utilization is the concern of sealing over active caries lesions. This study evaluated detection and monitoring of caries lesions through a clear sealant over 44 mo. Sixty-four 7- to 10-year-old children with at least 2 permanent molars with International Caries Detection and Assessment System (ICDAS) scores 0-4 (and caries less than halfway through the dentin, radiographically) were examined with ICDAS, DIAGNOdent, and quantitative light-induced fluorescence (QLF) before sealant placement and 1, 12, 24, and 44 mo (except QLF) after. Bitewing radiographs were taken yearly. DIAGNOdent and QLF were able to distinguish between baseline ICDAS before and after sealant placement. There was no significant evidence of ICDAS progression at 12 mo, but there was small evidence of minor increases at 24 and 44 mo (14% and 14%, respectively) with only 2% ICDAS ≥ 5. Additionally, there was little evidence of radiographic progression (at 12 mo = 1%, 24 mo = 3%, and 44 mo = 9%). Sealant retention rates were excellent at 12 mo = 89%, 24 mo = 78%, and 44 mo = 70%. The small risk of sealant repair increased significantly as baseline ICDAS, DIAGNOdent, and QLF values increased. However, regardless of lesion severity, sealants were 100% effective at 12 mo and 98% effective over 44 mo in managing occlusal surfaces at ICDAS 0-4 (i.e., only 4 of 228 teeth progressed to ICDAS ≥ 5 associated with sealants in need of repair and none to halfway or more through the dentin, radiographically). This study suggests that occlusal surfaces without frank cavitation (ICDAS 0-4) that are sealed with a clear sealant can be monitored with ICDAS, QLF, or DIAGNOdent, which may aid in predicting the need for sealant repair.