Background
This study compared natural root caries lesions with artificial root caries lesions prepared with one of the two demineralising solutions.
Methods
Twelve natural root caries lesions on ...upper incisors and 24 artificial root lesions were prepared on sound root surfaces using 50 mM acetic acid, 1.5 mM CaCl2, 0.9 mM KH2PO4 at pH 5.0 or 80 mL/L Noverite K‐702 polyacrylate solution, 500 mg/L hydroxyapatite, 0.1 mol/L lactic acid at pH 4.8 (n = 12/group) for 96 hours. Lesions were scanned using micro‐CT. Inciso‐gingival oriented images were analysed and mineral density calculated at 7.5 μm increments from the surface to 225‐μm deep. Sectioned lesions were analysed by Knoop microhardness up to 250 μm from the lesion surface. Data were analysed by the Dunn's test with Bonferroni correction.
Results
Natural and artificial lesion mean mineral densities were not statistically different (P > 0.05). Mineral density from the surface to 75 μm was greater in natural lesions and from 150 to 225 μm was greater in artificial lesions (P < 0.05). Microhardness values were statistically higher in artificial lesions (P < 0.05); no difference was found among artificial lesions produced by the two solutions (P > 0.05). Mineral density and microhardness of natural and artificial root caries are different from each other. A greater mineralized surface layer existed on natural lesions.
Abstract Objectives This study compared the effect of three flavonoids: proanthocyanidin, naringin and quercetin on the modulus of elasticity (MOE) and ultimate tensile strength (UTS) of ...demineralised dentine. Methods Thirty teeth were sectioned into 0.5 mm × 1.7 mm × 7 mm beams for MOE measurement. Another 30 non-carious molars were sectioned into 0.5 mm × 0.5 mm thick dentine beams for UTS testing. Demineralised specimens were divided into three groups according to treatments: 6.5% proanthocyanidin, 6.5% quercetin and 6.5% naringin. Specimens were kept in their respective solutions and tested at baseline, 10 min, 30 min, 1 h and 4 h. The MOE of each specimen was determined using a three-point bending test at a crosshead speed of 0.5 mm/min. For UTS evaluation, each specimen was tested in tension until failure using a crosshead speed of 1 mm/min. Means and standard deviation were calculated. Two-way ANOVA and Tukey test were used to evaluate the effect of flavonoid treatment and treatment duration on MOE and UTS. Results Both MOE and UTS were significantly affected by flavonoid treatment ( p < 0.001) and treatment duration ( p < 0.001). Interaction of the two factors was significant for MOE ( p < 0.001), but not for UTS ( p > 0.05). Flavonoid treatment improved the mechanical properties of demineralised dentine in the order: proanthocyanidin > quercetin > naringin. It took a longer time for the flavonoids to produce a significant change in UTS, when compared to MOE. Conclusion Proanthocyanidin was more effective than quercetin and naringin in improving biomechanical properties of dentine matrix, thereby enhancing preventive and reparative dental therapies. Clinical Significance Despite its larger molecular size, proanthocyanidin was more effective than quercetin and naringin, in enhancing the biomechanical properties of demineralised dentine.
Glass ionomer cements (GICs) are considered the material of choice for restoration of root carious lesions (RCLs). When bonding to demineralized dentin, the collapse of dentinal collagen during ...restorative treatment may pose challenges. Considering its acidic nature and collagen biomodification effects, proanthocyanidin (PAC) could be potentially used as a dentin conditioner to remove the smear layer while simultaneously acting to biomodify the dentinal collagen involved in the bonding interface. In this study, 6.5% w/v PAC was used as a conditioner for sound (SD) and laboratory demineralized (DD) root dentin before bonding to resin-modified GIC (FII), casein phosphopeptide–amorphous calcium phosphate (CPP-ACP)–modified GIC (FVII), or a high-viscosity GIC (FIX). Root dentin conditioned with deionized distilled water (DDW) or polyacrylic acid (PAA) served as controls. Results indicated FII showed higher shear bond strength (SBS) on SD than the other 2 GICs, especially in PAA-conditioned samples; FIX showed significantly higher SBS than FII and FVII on PAA- or PAC-conditioned DD. In each category of GIC, PAA and PAC did not have a significant influence on SBS in most cases compared to DDW except for a significant decrease in PAC-conditioned SD bonded to FII and a significant increase in PAA-conditioned DD bonded to FIX. The bonding interface between GIC and SD was generally more resistant to the acid-base challenge than DD. Although the alterations in failure modes indicated a compromised interfacial interaction between GICs and PAC-treated root dentin, biomodification effects of PAC on dentin were observed from Raman microspectroscopy analysis in terms of the changes in mineral-to-matrix ratio and hydroxyproline-to-proline ratio of dentin adjacent to the bonding interface, especially of DD. Results from this study also indicated the possibility of using in situ characterization such as Raman microspectroscopy as a complementary approach to SBS test to investigate the integrity of the bonding interface.
The aim of this literature review is to explore the treatment methods for root caries in laboratory and clinical research in the last decade. A systematic search of publications in PubMed and Web of ...Science databases was performed. The timespan was limited to the last 10 years and English language. Further retrieval was conducted using the search terms of specific therapies or treatments. Eighty‐two articles were included in this systematic review and full texts were retrieved. Types of studies included laboratory studies and clinical trials. Therapeutic approaches for root caries without risk of pulp exposure can be categorized into non‐invasive and restorative treatment. Non‐invasive treatments which targeted different causative factors of root caries have been developed in the last decade. Accordingly, several artificial caries model systems have been proposed for the study of root caries in the laboratory. Carious tissue excavation techniques and restorative materials and procedures have been modified to improve the prognosis of invasive treatment. It is of importance to determine the most appropriate therapy for root caries and further clinical trials are needed to draw firm conclusions concerning the efficacy and consistency of the various treatment methods proposed.
The aim of this review was to assess the methodologies used in previously published prospective randomized clinical trials on chemomechanical caries removal and to conduct a meta-analysis to quantify ...the differences in the excavation time between chemomechanical and conventional caries removal methods.
An electronic search was performed using Scopus, PubMed, EBSCO host, and Cochrane Library databases. The following categories were excluded during the assessment process: non-English studies published before 2000, animal studies, review articles, laboratory studies, case reports, and nonrandomized or retrospective clinical trials. The methodologies of the selected clinical trials were assessed. Furthermore, the reviewed clinical trials were subjected to meta-analysis for quantifying the differences in excavation time between the chemomechanical and the conventional caries removal techniques.
Only 19 randomized clinical trials fit the inclusion criteria of this systematic review. None of the 19 reviewed trials completely fulfilled Delphi's ideal criteria for quality assessment of randomized clinical trials. The meta-analysis results revealed that the shortest mean excavation time was recorded for rotary caries excavation (2.99±0.001 minutes), followed by the enzyme-based chemomechanical caries removal method (6.36±0.08 minutes) and the the hand excavation method (atraumatic restorative technique; 6.98±0.17 minutes). The longest caries excavation time was recorded for the sodium hypochlorite-based chemomechanical caries removal method (8.12±0.02 minutes).
It was found that none of the current reviewed trials fulfilled all the ideal requirements of clinical trials. Furthermore, the current scientific evidence shows that the sodium hypochlorite-based (Carisolv) chemomechanical caries removal method was more time consuming when compared to the enzyme-based (Papacarie) chemomechanical and the conventional caries removal methods. Further prospective randomized controlled clinical trials evaluating the long-term follow-up of papain-treated permanent teeth are needed.
Background
Curriculum reforms are being driven by globalization and international standardization. Although new information technologies such as dental haptic virtual reality (VR) simulation systems ...have provided potential new possibilities for clinical learning in dental curricula, infusion into curricula requires careful planning.
Methods
This study aimed to identify current patterns in the role and integration of simulation in dental degree curricula internationally. An original internet survey was distributed by invitation to clinical curriculum leaders in dental schools in Asia, Europe, North America, and Oceania (Australia and New Zealand).
Results
The results (N = 62) showed Asia, Europe and Oceania tended towards integrated curriculum designs with North America having a higher proportion of traditional curricula. North America had limited implementation of haptic VR simulation technology but reported the highest number of scheduled simulation hours. Australia and New Zealand were the most likely regions to incorporate haptic VR simulation technology.
Conclusions
This survey indicated considerable variation in curriculum structure with regionally‐specific preferences being evident in terms of curriculum structure, teaching philosophies and motivation for incorporation of VR haptic simulation into curricula. This study illustrates the need for an improved evidence base on dental simulations to inform curriculum designs and psychomotor skill learning in dentistry.
Background
Restorative materials have varying surface characteristics from natural tooth, which may affect oral‐bacterial surface attachment/growth. This study examined 48‐h Streptococcus mutans (Sm) ...or Actinomyces naeslundii (An) growth on various restorative materials and tooth surfaces.
Methods
The quantity and viability of 48‐hour‐old Sm and An growth on polished (180‐ or 1200‐grits), saliva‐coated resin composite (RC), glass ionomer cements (GIC), resin‐modified GIC (R‐GIC), GIC containing casein phosphopeptide–amorphous calcium phosphate (3% (w/w), CPP‐ACP GIC), amalgam or tooth blocks (5 × 5 × 1 mm3) were examined.
Results
Rough‐polished (arithmetical mean deviation of the assessed surface roughness profile (Ra): 1.50–1.75 µm) material surfaces revealed relatively higher proportion of inorganic, positively charged surface components ((Si + Al)/C) and greater quantity of surface attached bacteria than smooth polished (Ra: 0.20–0.35 µm) material groups (P < 0.001). Less Sm and An were observed on tooth, and smooth polished GIC and CPP‐ACP GIC surfaces than on resin‐based materials (RC, R‐GIC) and amalgam (P ≤ 0.003). Viability of Sm was found to be lower on amalgam surfaces (P < 0.001), whereas that of An appeared lower on both amalgam surfaces and rough CPP‐ACP GIC surfaces (P ≤ 0.033).
Conclusion
Surface roughness exerted a pronounced effect on in vitro growth/attached Sm/An quantity but may not have an impact on bacteria viability. Interestingly, despite smoother surfaces of various materials tested, fewer Sm/An were observed attaching on tooth surfaces.
Background
This study evaluated the ability of a CPP‐ACP‐modified Glass–ionomer cement (GIC) to inhibit demineralization around the margins of cervical cavities in natural teeth in comparison with a ...Giomer and conventional GIC with and without coating.
Methods
Thirty‐two sound human molars were used. Box‐shaped cavities were prepared along the CEJ. Teeth were randomly divided into four groups and restored with Equia Forte Fil, Coated Equia Forte Fil, Fuji VII EP or Beautifil II. Teeth were subjected to pH cycling. Micromorphological and elemental analyses were done using SEM and EDX. Polarized light microscope analysis and microhardness tests were also performed.
Results
Microhardness tests on enamel showed a significant difference between the coated Equia group, Equia and Beautifil II groups (P < 0.05). Dentine results showed significant differences between the coated Equia group and all other groups (P < 0.05). Elemental analysis showed significant differences in calcium weight percentage among the first and second observation levels in all groups (P < 0.05). A significant difference was found between the coated Equia group and the other three groups (P < 0.05).
Conclusions
All tested materials showed some ability to resist demineralization at the restoration margins. The coated GIC restoration showed better outcomes compared with the other tested materials.
This aim of this review is to explore the current research related to crosslinking agents used on dentine. A systematic search of publications in PubMed and Web of Science databases was performed. ...Further retrieval was conducted using the search terms of specific names of crosslinkers. Reviews, conference abstracts, dissertation and theses, non-English articles, studies of intrinsic crosslinking of dentine, studies of adhesives without specific crosslinker components, studies of crosslinker applications in other collagenous tissues or tooth-like structures and irrelevant studies were excluded. Manual screening was conducted on the bibliographies of remaining papers to identify other relevant articles. One hundred and one articles were included in this systematic review and full texts were retrieved. Both synthetic and naturally derived crosslinkers have been found to exhibit significant effects in biomodification of dentine via their multiple interactions with the dentine matrix. A stable matrix network or a durable hybrid layer in dentine bonding could be achieved, where the dentine collagen fibrils show improved biochemical and biomechanical properties and enzymatic biodegradation is reduced. Although no crosslinkers have been tested in clinical trials, extensive research has been conducted in laboratory studies to investigate their potential applicability for inhibition of demineralisation and/or promotion of remineralisation, caries prevention as well as improvement of bonding performance of adhesive systems. Further studies are needed to develop the feasibility for clinical use, reduce side effects as well as explore mechanisms of action and long-term effectiveness.
In this laboratory study, the microtensile bond strengths (μTBS) of resin-modified glass ionomer cement (RM-GIC) to sound and artificial caries-affected bovine root dentin (ACAD) using three ...different conditioning agents were evaluated after 24 hours and three months. The fractured interface was examined with a scanning electron microscope (SEM). Specimens were created on bovine root dentin that was embedded in epoxy resin. For the ACAD specimens, artificial carious lesions were created. The RM-GIC (Fuji II LC) was applied either directly (no treatment), after application of self conditioner, cavity conditioner, or 17% ethylenediamine tetraacetic acid (EDTA) applied for 60 seconds, on sound dentin and ACAD, then light cured. They were stored in artificial saliva for 24 hours or three months. Following this, the specimens were cut into sticks for the μTBS test, and the failure mode of the debonded specimens was examined by using SEM. Pretest failures were excluded from the statistical analysis of the μTBS values because of their high incidence in some groups. Results showed that the μTBS values were significantly affected by the dentin substrate as well as the conditioning agent. Self conditioner provided the highest and most stable μTBS values, while cavity conditioner showed stable μTBS values on sound dentin. Both self conditioner and cavity conditioner had significantly higher μTBS values than the no treatment groups. EDTA conditioning reduced the μTBS after three months to sound dentin, while it showed 100% pretest failure with ACAD for both storage periods.
PDF
