Browsing by Author "González-Cabezas, Carlos"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Age effect on presence, susceptibility and treatment of erosive tooth wear
    (2018) Algarni, Amnah Abdullah; Hara, Anderson T.; Lippert, Frank; Platt, Jeffrey A.; González-Cabezas, Carlos; Ungar, Peter
    Erosive tooth wear (ETW) is a growing dental condition often associated with aging. This in-vitro project comprised three studies aiming to investigate the impact of tooth age on ETW susceptibility and prevention. In the first study, un-identified extracted premolars were collected and had their ages estimated using validated dental forensic methods. The premolars were examined to investigate the relationship between age and presence and severity of ETW, as well as other main dental-hard tissues conditions. ETW, dental caries, fluorosis, extrinsic staining and tooth color were evaluated using established clinical indices. In the second study, the tooth age impact on ETW susceptibility and response to preventive treatments (Sn+F, NaF, and de-ionized water control) were evaluated using representative samples from the initial study. Enamel and dentin specimens were prepared and subjected to daily erosion-treatmentremineralization cycling procedure. Surface loss (SL) was determined during and after the cycling, by optical profilometry. Similar protocol was adopted in the third study with the addition of toothbrushing abrasion to the model, in order to explore the interplay between age and toothpaste abrasivity on erosion-abrasion development. SL was measured during and after the erosion-toothbrushing-remineralization cycling. The relationships between age and the investigated variables were assessed using linear regression models. In conclusion: 1. The presence and severity of ETW, dental caries, and extrinsic staining increased with age, while of enamel fluorosis decreased. Tooth also showed to be darker with age. 2. Susceptibility of enamel and dentin to demineralization increased with age. Sn+F showed the highest anti-erosive efficacy, and was not affected by age. NaF showed lower efficacy on dentin, which increased with age. 3. Enamel and dentin SL increased with toothpaste abrasivity level. Dentin SL also increased with age. Age effect on enamel SL was observed only with low abrasive toothpaste. Age-related changes on enamel and dentin affected ETW development.
  • Thumbnail Image
    Item
    Effect of toothbrushing duration and dentifrice quantity on enamel remineralisation: An in situ randomized clinical trial
    (Elsevier, 2016-12) Creeth, J. E.; Kelly, Sue A.; González-Cabezas, Carlos; Karwal, R.; Martinez-Mier, Esperanza A.; Lynch, R. J. M.; Bosma, M.; Zero, Domenick T.; Department of Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    Objectives The influence of toothbrushing duration and dentifrice quantity on fluoride efficacy against dental caries is poorly understood. This study investigated effects of these two oral hygiene factors on enamel remineralisation (measured as surface microhardness recovery [SMHR]), enamel fluoride uptake (EFU), and net acid resistance (NAR) post-remineralisation in a randomized clinical study using an in situ caries model. Methods Subjects (n = 63) wore their partial dentures holding partially demineralised human enamel specimens and brushed twice-daily for two weeks, following each of five regimens: brushing for 120 or 45 s with 1.5 g of 1150 ppm F (as NaF) dentifrice; for 120 or 45 s with 0.5 g of this dentifrice; and for 120 s with 1.5 g of 250 ppm F (NaF) dentifrice. Results Comparing brushing for 120 s against brushing for 45 s, SMHR and EFU increased by 20.0% and 26.9% respectively when 1.5 g dentifrice was used; and by 22.8% and 19.9% respectively when 0.5 g dentifrice was used. Comparing brushing with 1.5 g against brushing with 0.5 g dentifrice, SMHR and EFU increased by 35.3% and 51.3% respectively when brushing for 120 s, and by 38.4% and 43.0% respectively when brushing for 45 s. Increasing brushing duration and dentifrice quantity also increased the NAR value. The effects of these two oral hygiene factors on SMHR, EFU, and NAR were statistically significant (p < 0.05 in all cases). Conclusion Brushing duration and dentifrice quantity have the potential to influence the anti-caries effectiveness of fluoride dentifrices. Study NCT01563172 on ClinicalTrials.gov. Clinical significance The effect of two key oral hygiene regimen factors – toothbrushing duration and dentifrice quantity – on fluoride’s anticaries effectiveness is unclear. This 2-week home-use in situ remineralisation clinical study showed both these factors can influence fluoride bioactivity, and so can potentially affect fluoride’s ability to protect against caries.
  • Thumbnail Image
    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, Sarah
    The 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.
  • Thumbnail Image
    Item
    Monitoring of Simulated Erosive Tooth Wear by Cross-Polarization Optical Coherence Tomography
    (2019-06) Alghilan, Maryam Abdulkareem; Hara, Anderson T.; Lippert, Frank; Platt, Jeffrey A.; González-Cabezas, Carlos; Fried, Daniel
    Erosive tooth wear (ETW) is an emerging dental condition manifested clinically as tooth surface loss, eventually impairing the teeth’s structural integrity, function, and esthetics. Both research and practice are in need of a quantitative, non-destructive method to monitor ETW. Cross-polarization optical coherence tomography (CP-OCT), an advanced imaging tool, shows great potential to fulfill this need, but its feasibility and shortcomings remain unclear. In this dissertation, I explored the capability of CP-OCT to monitor ETW in three in vitro studies, one per chapter. Chapter 2 investigated the effects of enamel surface roughness and dental erosion severity on CP-OCT dental surface loss measurements. Chapter 3 tested the effects of enamel surface roughness and dental erosion on CP-OCT enamel thickness measurements at different simulated wear levels. Chapter 4 explored the ability of CP-OCT to quantify the thickness of natural and wornout enamel surfaces and to estimate longitudinally the wear depths resulting from simulated wear. I concluded: (1) enamel surface roughness did not affect CP-OCT measurements of enamel surface loss, however, the estimated error limited the appropriate assessment of the initial stages of dental erosion surface loss using CP-OCT; (2) enamel surface roughness and dental erosion did not affect CP-OCT enamel thickness measurements, and the CP-OCT differentiated the simulated enamel wear levels; and (3) CP-OCT quantified thickness of natural enamel before, during, and after the tooth wear simulation and allowed wear depth estimation following the simulated wear.
  • Thumbnail Image
    Item
    A novel approach to aesthetically treat arrested caries lesions
    (2017) Alangari, Sarah Sultan A.; Hara, Anderson T.; Lippert, Frank; Platt, Jeffrey A.; González-Cabezas, Carlos; Li, Yiming
    In this thesis, we proposed and investigated the efficacy and safety of dental bleaching as a non-invasive aesthetic treatment option for stained arrested caries lesions (s-ACLs). Chapter 1 reports the suitability of this approach in extracted human teeth, as well as in a selected clinical case. Visual improvement in the color lighteness of the s-ACLs was observed and reported in photographs. In order to systematically study the impact of dental bleaching on the s-ACLs, we developed in vitro models simulating the development of metallic and non-metallic s-ACLs (Chapter 2). Human dental specimens were submitted to incipient caries-like lesion formation, followed by a 5-day cycling protocol based on remineralization and staining episodes. The created lesions were then bleached (simulating in-office/40% hydrogen peroxide). Color change was measured spectrophotometrically at baseline, after lesion creation, staining/remineralization cycling and bleaching; while mineral loss and lesion depth were quantified by transversal microradiography after staining/remineralization cycling. Metallic s-ACLs were darker, more remineralized and more difficult to bleach, compared to the non-metallic ones (p<0.05). In Chapter 3, we tested the efficacy and safety of different dental bleaching systems (simulating at-home/15% carbamide peroxide and in-office/40% hydrogen peroxide) using the in vitro models previously developed. Similar methods and outcomes were used, with the addition of demineralization after bleaching to simulate and test changes in caries susceptibility. At-home bleaching showed greater efficacy in color improvement compared to in-office (p<0.05), but also increased susceptibility to further demineralization (p<0.05), regardless of the type of stain. Overall, bleached non-metallic s-ACLs were more susceptible to demineralization compared to metallic ones (p<0.05). Within the limited laboratory testing conditions, we concluded that dental bleaching can improve the aesthetics of s-ACLs, with efficacy being dependent on the nature of the stain. At-home bleaching presented greater efficacy, but also raised some potential safety concerns, which should be further investigated in clinical conditions. In-office bleaching protocol showed to be an effective and safe procedure for the aesthetic treatment of stained arrested caries lesions.
  • Thumbnail Image
    Item
    Trend-analysis of dental hard-tissue conditions as function of tooth age
    (Elsevier, 2018-07) Algarni, Amnah A.; Ungar, Peter S.; Lippert, Frank; Martinez-Mier, E. Angeles; Eckert, George J.; González-Cabezas, Carlos; Hara, Anderson T.; Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    Objective This retrospective in-vitro study investigated tooth age effect on dental hard-tissue conditions. Methods Unidentified extracted premolars (n = 1500) were collected and their individual age was estimated (10–100 (±10) years old (yo)) using established dental forensic methods Dental caries, fluorosis and tooth wear (TW) were assessed using the International Caries Detection and Assessment System (ICDAS; 0–5 for crown and 0–2 for root), Thylstrup-Fejerskov (TFI; 0–9) and Basic Erosive Wear Examination (BEWE; 0–3) indices, respectively. Staining and color were assessed using the modified-Lobene (MLI) (0–3) and VITA shade (B1-C4) indices, respectively. Relationships between indices and age were tested using regression models. Results Starting at age ∼10yo, presence of caries increased from 35% to 90% at ∼50yo (coronal), and from 0% to 35% at ∼80yo (root). Caries severity increased from ICDAS 0.5 to 2 at ∼40yo and from ICDAS 0 to 0.5 at ∼60yo for coronal and root caries, respectively. Presence of TW increased from 25% (occlusal) and 15% (smooth-surfaces) to 100% at ∼80yo. TW severity increased from BEWE 0.5 to 2 at ∼50yo (occlusal) and ∼0.3 to 1.5 at ∼50yo (smooth-surfaces). Percentage and severity of fluorosis decreased from 70% to 10% at ∼80yo, and from TFI 1 to 0 at ∼90yo, respectively. Percentage of extrinsic staining increased from 0% to 85% at ∼80yo and its severity increased from MLI 0 to 2 at ∼70yo. Color changed from A3 to B3 at ∼50yo (crown), and from C2 to A4 at ∼85yo (root). Conclusions Aging is proportionally related to the severity of caries, TW, staining, and inversely to dental fluorosis. Teeth become darker with age