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Acta Odontol Scand [journal]
- Chondrogenic potential of stem cells from human exfoliated deciduous teeth in vitro and in vivo. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Mar 3.
Abstract Objective. The aim of this study was to investigate the chondrogenic potential of stem cells from human exfoliated teeth (SHED). Materials and methods. SHED cultures were isolated from human exfoliated deciduous teeth. Colony-forming capacity, odonto/osteogenic and adipogenic potential were measured. SHED were cultured for 2 weeks in chondrogenic differentiation medium containing dexamethasone, insulin, ascorbate phosphate, TGF-β3 and bFGF. Toluidine blue staining and safranin O staining were used for chondrogenesis analysis. The related markers, type II collagen and aggrecan, were also investigated using immunohistochemistry. SHED were seeded onto the β-TCP scaffolds and transplanted into the subcutaneous space on the back of nude mice. The transplants were recovered at 2, 4 and 8 weeks post-transplantation for analysis. Results. SHED showed colony-forming capacity, odonto/osteogenic and adipogenic differentiation capacity. Chondrogenic differentiation was confirmed by toluidine blue staining, safranin O staining, type II collagen and aggrecan immunostaining. After in vivo transplantation, SHED recombined with β-TCP scaffolds were able to generate new cartilage-like tissues. Conclusions. The ﬁndings demonstrate the chondrogenic differentiation capacity of SHED both in vitro and in vivo models, suggesting the potential of SHED in cartilage tissue engineering.
- Effect of different monomer-based composites and acid etching pre-treatment of enamel on the microleakage using self-etch adhesives systems. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Mar 3.
Abstract Objective. To evaluate quantitatively the marginal microleakage of restorations carried out with self-etching adhesives with or without prior phosphoric enamel acid etching of silorane or methacrylate resin-based composite restorations subjected to thermal cycling. Materials and methods. Forty cavities were prepared at the proximal surface of bovine incisors and randomly divided according to the etching of the enamel and restorative system used. The groups were restored with methacrylate [Adper SE Plus adhesive (3M ESPE) + Filtek Z250 (3M ESPE)] or silorane [Filtek LS adhesive (3M ESPE) + Filtek LS composite (3M ESPE)] restorative systems, light-cured using a LED unit (Bluephase 16i, Vivadent). After restorative procedure and thermocycling (1000 cycles), the specimens were immersed in methylene blue for 2 h. The specimens were triturated and the powder was used for analysis in an absorbance spectrophotometer. Data were statistically analyzed by 2-way ANOVA (alpha = 0.05). Results. No statistical difference between the restorative materials tested with or without previous acid etching of enamel in Class II marginal microleakage was observed (p > 0.05). Conclusions. The use of acid etching prior to self-etching adhesives did not interfere on the microleakage of methacrylate- or silorane-based restorations.
- Dental plaque pH and ureolytic activity in children and adults of a low caries population. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Feb 13.
Abstract Objectives. The aim of this study was to evaluate the plaque pH level and ureolytic activity among children and adults of Karen Hill tribes. Methods. Thirty-four children aged 6-10 years and 46 adults aged 20-38 years were interviewed regarding oral hygiene practices, sucrose intake and betel chewing. Caries experience (DMFT and DT), calculus, bleeding on probing (BoP) and Plaque index (PlI) were registered. Ureolytic activity in supragingival plaque was tested at two interproximal sites (11/12 and 41/42) with the rapid urease test (RUT). Registration of plaque pH was performed at two interproximal sites (15/16 and 31/41) before, during and 30 min after rinsing with an urea solution (0.25%). Four interproximal plaque samples (one from each quadrant) per individual were collected to test the bacterial composition using the checkerboard technique. Results. Children and adults had similarly low DMFT and DT values. Children had a higher baseline pH and a higher ureolytic activity in the maxilla (p < 0.05) compared with adults. A significant correlation (r (2) = 0.63) was found between baseline pH and urease activity in the mandibular anterior teeth. Caries-free individuals had a higher baseline pH compared with caries active individuals in the anterior mandibular region (p < 0.01). The microbiological composition was characterized by an anaerobic low acidiogenic microbiota. Conclusions. Dental plaque pH is related to the ureolytic activity, which explains the low acidogenic plaque microflora and the low caries levels in the Karen population.
- Characteristics of the early stages of intravenous bisphosphonate-related osteonecrosis of the jaw in patients with breast cancer. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Feb 12.
Abstract Objective. The clinical features of the early stages of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in patients with breast cancer remain unclear. A retrospective cohort study was conducted of patients with breast cancer who received intravenous bisphosphonate (BP) treatment in a single center in order to clarify the status of the early stages of BRONJ. Materials and methods. A BRONJ oral monitoring program was established in 247 breast cancer patients given intravenous BP treatment at the institution. The differences in age, BP treatment period, number of remaining teeth, oral hygiene status, presence of regular oral monitoring and the existence of suspected BRONJ (stage 0) among eight BRONJ and 36 non-BRONJ subjects who completed oral examinations were then compared. Results. BRONJ was observed in 0.4% of subjects on the first visit to the oral surgery clinic and in 3.2% of subjects during the follow-up period. Logistic regression analysis revealed that the odds ratio for identifying patients with BRONJ during follow-up by the presence of stage 0 at first visit was 24.0 (95% confidence interval [CI] = 3.6-161.7). The area under the receiver operating characteristic curve for identifying subjects with BRONJ by the presence of stage 0 was 0.82 (95% CI = 0.63-1.00). Conclusion. The results suggest that patients with stage 0 BRONJ on the first visit may progress to advanced BRONJ during the follow-up period. The oral monitoring program may contribute to the early detection of BRONJ.
- Radiographic display of carious lesions and cavitation in approximal surfaces: Advantages and drawbacks of conventional and advanced modalities. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Feb 10.
Abstract Background. Treatment strategies have changed with efforts on arresting carious lesions suspected to have an intact surface sparing operative treatment for cavitated lesions. Radiography is still the most recommended adjunct method in the diagnosis of clinically inaccessible approximal surfaces. Bitewing radiography. The major drawback of bitewing radiography for caries diagnosis is that the clinical state of the surface cannot be determined; i.e. if cavitation has developed or the demineralized surface is still intact. Based on studies of the relationship between radiographic lesion depth and clinical cavitation in approximal surfaces, a threshold for operative treatment decision has been suggested when a lesion is observed radiographically more than one-third into dentine. However, the results from previous studies are contradictory and the majority of studies are ∼25 years old. In addition, there are few longitudinal observational studies on the behaviour of dentinal carious lesions, particularly in adults. Cone beam computed tomography. Cone beam CT is an advanced 3-dimensional radiographic modality, which seems much more accurate than intra-oral modalities for displaying cavitation in approximal surfaces. Nonetheless, there are several drawbacks with CBCT, such as radiation dose, costs and imaging artefacts. Therefore, CBCT cannot be advocated at current as a primary radiographic examination with the aim of diagnosing cavitated carious lesions. Conclusions. Bitewing radiography is, thus, still state-of-the-art as an adjunct in diagnosing carious lesions in clinically inaccessible approximal surfaces. The risk for cavitation is related to lesion depth, but new studies are needed in both child and adult populations to validate current thresholds for the operative treatment decision based on the radiographic lesion depth.
- Direct effect of chlorine dioxide, zinc chloride and chlorhexidine solution on the gaseous volatile sulfur compounds. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Feb 10.
Abstract Objective. This study focused on the ability of aqueous anti-volatile-sulfur-compound (VSC) solutions to eliminate gaseous VSCs by direct contact in a sealed space to describe possible mode of action of anti-VSC agents. Materials and methods. Twenty milliliters of each experimental solution, 0.16% sodium chlorite, 0.25% zinc chloride, 0.1% chlorhexidine and distilled water, was injected into a Teflon bag containing mixed VSCs, hydrogen sulfide, methyl mercaptan and dimethyl sulfide and mixed vigorously for 30 s. The VSC concentration was measured by gas chromatography before, immediately after, 30 min and 60 min after mixing. Results. The sodium chlorite solution reduced the VSC concentration remarkably. After mixing, nearly all VSCs were eliminated immediately and no VSCs were detected at 30 and 60 min post-mixing. However, in the other solutions, the VSC concentration decreased by ∼30% immediately after mixing and there was no further decrease. Conclusion. The results suggest that sodium chlorite solution has the effect of eliminating gaseous VSCs directly. This must be because it can release chlorine dioxide gas which can react directly with gaseous VSCs. In the case of other solutions that have been proved to be effective to reduce halitosis clinically, it can be proposed that their anti-VSC effect is less likely due to the direct chemical elimination of gaseous VSCs in the mouth.
- Determination of canal orifice co-ordinates and MB2 incidence of maxillary first molars in a Turkish sub-population. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Feb 4.
Abstract Objectives. To measure the co-ordinates of the root canal orifices and to determine the incidence of mesiobuccal-2 (MB2) in maxillary first molars in a Turkish sub-population. Materials and methods. Standard digital photographs were taken under a stereomicroscope from the occlusal aspect of each tooth (n = 176) before and after crown removal. Canal orifices were negotiated under moderate magnification using dental loupes. The coordinates of the orifices and the distances of each from the central fossa were measured by using geographic software. Intensity maps of the orifice locations were created by using the co-ordinates of all canal orifices. A representative map was drawn using the mean values of orifice locations and access projection area. Results. In the right maxillary first molars, the mean values for the (X, Y) co-ordinates were (0.67, 2.68) for mesiobuccal-1 (MB1), (0.81, 0.84) for MB2, (-1.12, 1.26) for distobuccal-1 (D1), (-0.89, 0.23) for distobuccal-2 (D2) and (0, -2.50) for palatinal (P); the corresponding mean values in the left maxillary first molars were (-0.78, 2.56), (-0.98, 0.90), (0.99, 1.18), (0.69, 0.78) and (0.00, -2.53), respectively. The average MB1-MB2 distance was 1.97 mm. Distobuccalcanal orifices were localized at the distal side of the center in 98.3% of teeth. The incidence of MB2 was 46.02%. Conclusions. The distobuccal canal orifice is mostly located on the distal side of the central fossa. Thus, it should be considered that the access cavity of the maxillary molars may not be always limited mesially. The incidence of MB2 in this sub-population was 46.02%, which is of great importance clinically.
- Preparation and properties of calcium-silicate filled resins for dental restoration. Part II: Micro-mechanical behaviour to primed mineral-depleted dentine. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Feb 4.
Abstract Objective. Evaluating microtensile bond strength (μTBS) and Knoop micro-hardness (KHN) of resin bonded-dentine interfaces created with two methacrylate-based systems either incorporating Bioglass® 45S5 (3-E&RA/BG) or MTA (3-E&RA/WMTA). Materials and methods. Solvated resins (50% ethanol/50% co-monomers) were used as primers while their neat counterparts were filled with the two calcium-silicate compounds. Application of neat resin adhesive with no filler served as control (3-E&RA). μTBS, KHN analysis and confocal tandem scanning microscopy (TSM) micropermeability were carried out after 24 h and 10 months of storage in phosphate buffer solution (DPBS). Scanning electron microscopy (SEM) was also performed after debonding. Results. High μTBS values were achieved in all groups after 24 h of DPBS storage. On the contrary, solely the specimens created using 3-E&RA/BG and 3-E&RA/WMTA agents showed no significant reduction in terms of μTBS even after 10 months in DPBS; similarly, they did not restore the average superficial micro-hardness to the level of sound dentine, but maintained unchanged KHN values, and no statistical decrease was found following 10 months of DPBS storage. The only statistically significant changes occurred in the resin-dentine interfaces bonded with 3-E&RA that were subjected to a reduction of both μTBS and KHN values with ageing. In terms of micropermeability, adverse results were obtained with 3-E&RA while 3-E&RA/BG and 3-E&RA/WMTA demonstrated a beneficial effect after prolonged DPBS storage. Conclusion. Calcium-silicate filled composite resins performed better than a current etch-and-rinse adhesive and had a therapeutic/protective effect on the micro-mechanical properties of mineral-depleted resin-dentine interfaces. Clinical significance. The incorporation of calcium-silicates into dental restorative and bonding agents can create more biomimetic (life-like) restorations. This will not only enable these materials to mimic the physical characteristics of the tooth structure, but will also stabilize and protect the remaining dental hard tissues.
- Influence of ceramic thickness and type on micromechanical properties of light-cured adhesive bonding agents. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Feb 4.
Abstract Objective. The aim of this study was to evaluate the micromechanical properties of different adhesive bonding agents when polymerized through ceramics. Materials and methods. Sixty sound extracted human third molars were selected and the crowns were sectioned perpendicular to the long axis in order to obtain dentin slices to be bonded with one of the following adhesives: Syntac/Heliobond (Ivoclar-Vivadent) or Adper-Scotchbond-1XT (3M-ESPE). The adhesives were cured by using a LED-unit (Bluephase®, Ivoclar Vivadent) with three different curing times (10 s, 20 s and 30 s) under two ceramics (IPS-e.max-Press, Ivoclar-Vivadent; IPS-Empress®CAD, Ivoclar-Vivadent) of different thicknesses (0 mm, 0.75 mm, 2 mm). Thirty groups were included, each containing 60 measurements. Micromechanical properties (Hardness, HV; indentation modulus, E; and creep, Cr) of the adhesives were measured with an automatic microhardness indenter (Fisherscope H100C, Germany). Data were statistically analyzed by using one-way ANOVA and Tukey's post-hoc test, as well as a multivariate analysis to test the influence of the study parameters (SPSS 18.0). Results. Significant differences were observed between the micromechanical properties of the adhesives (p < 0.05). The ceramic type showed the highest effect on HV (Partial-eta squared (η (2)) = 0.109) of the tested adhesives, while E (η (2) = 0.275) and Cr (η (2) = 0.194) were stronger influenced by the adhesive type. Ceramic thickness showed no effect on the E and Cr of the adhesives. Conclusions. The adhesive bonding agents used in this study performed well by curing through different thicknesses of ceramics. The micromechanical properties of the adhesives were determined by the adhesive type and were less influenced by ceramic type and curing time.
- Preparation and properties of calcium-silicate filled resins for dental restoration. Part I: chemical-physical characterization and apatite-forming ability. [JOURNAL ARTICLE]
- Acta Odontol Scand 2014 Feb 4.
Abstract Objective. The aim of this study was to measure dimensional changes due to hygroscopic expansion and the bioactivity of two experimental methacrylate-based dental adhesives either incorporating Bioglass® 45S5 (3-E&RA/BG) or MTA (3-E&RA/WMTA). Materials and methods. 3-E&RA/BG, 3-E&RA/WMTA and a control filler-free resin blend (3-E&RA) were formulated from commercially available monomers. Water sorption (WS) and solubility (SL) behaviour were evaluated by weighing material disks at noted intervals; the relationship between degree of hydration and the glass transition temperature (Tg) was investigated by using differential scanning calorimetry (DSC). In vitro apatite-forming ability as a function of soaking time in phosphate-containing solutions was also determined. Kruskal-Wallis analysis of variance (ANOVA) was used to evaluate differences between groups for maximum WS, SL, net water uptake and the percentage change in Tg values. Post-ANOVA pair-wise comparisons were conducted using Mann-Whitney-U tests. Results. 3-E&RA/BG and 3-E&RA/WMTA exhibited values of maximum WS and net water uptake that were significantly higher when compared to 3-E&RA. However, no statistically significant differences were observed in terms of SL between all the adhesives. The addition of the Bioglass® 45S5 and MTA to the 3-E&RA showed no reduction of the Tg after 60 days of storage in deionized water. ATR Fourier Transform Infrared Spectroscopy (ATR-FTIR) of the filled resin disks soaked in DPBS for 60 days showed the presence of carbonate ions in different chemical phases. Conclusion. Dentine bonding agents comprising calcium-silicates are not inert materials in a simulated oral environment and apatite formation may occur in the intra-oral conditions. Clinical significance. A bioactive dental material which forms apatite on the surface would have several benefits including closure of gaps forming at the resin-dentine interface and potentially better bond strength over time (less degradation of bond).