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Archives of Oral Biology Sep 2023Variation in enamel and dentine mineral concentration and total effective density can be reliably collected using Micro-CT scans. Both variables are suggested to reflect...
OBJECTIVE
Variation in enamel and dentine mineral concentration and total effective density can be reliably collected using Micro-CT scans. Both variables are suggested to reflect mechanical properties such as hardness and elastic modulus in dental tissues, meaning Micro-CT methods allow relative composition and mechanical properties to be collected non-destructively.
DESIGN
16 lower molars from 16 Catarrhine primates were Micro-CT scanned alongside hydroxyapatite phantoms using standardized settings and methods to calculate mineral concentration and total effective density. Mineral concentration, total effective density and thickness of dentine and enamel were calculated for four cusps, representing each 'corner' of the tooth and four lateral crown positions (i.e., mesial, buccal, lingual and distal).
RESULTS
The results show mean mineral concentration and total effective density values were higher in areas of thicker enamel, while the opposite was observed for dentine. Buccal positions had significantly higher mineral concentration and total effective density values than lingual areas. Cuspal positions had higher mean values than lateral enamel, for both dentine (mineral concentration cuspal: 1.26 g/cm; lateral: 1.20 g/cm) and enamel (mineral concentration cuspal: 2.31 g/cm; lateral: 2.25 g/cm). Mesial enamel had significantly lower values than other locations.
CONCLUSIONS
These common patterns across Catarrhine taxa may be linked to functional adaptations related to optimization of mastication and tooth protection. Variation in mineral concentration and total effective density may also be associated with wear and fracture patterns, and can be used as baseline information to investigate the effect of diet, pathological changes and aging on teeth through time.
Topics: Animals; Dentin; Dental Enamel; Molar; Tooth; Primates
PubMed: 37385050
DOI: 10.1016/j.archoralbio.2023.105752 -
Journal of the Mechanical Behavior of... May 2018Bonding to demineralized dentin of a diseased tooth has shown to be a significant clinical issue. This study evaluated the effect of 0.2% NaF-(NaF), MI...
Bonding to demineralized dentin of a diseased tooth has shown to be a significant clinical issue. This study evaluated the effect of 0.2% NaF-(NaF), MI Paste™-(CPP-ACP) and the self-assembling peptide 'P' (Ace-QQRFEWEFEQQ-NH) contained in Curodont™ Repair, have on microtensile bond strength-(µTBS) of two different adhesive systems (Adper™ Single Bond-(SB) or Clearfil™ SE Bond (CSE)) and wettability of demineralized dentin slices after remineralising agents were applied. The highest µTBS were found for the demineralized dentin-(DD) treated with CPP-ACP; both adhesives systems (p < 0.05) did not significantly difference from P treatment associated with SB, and also presented higher values than sound dentin-(SD/SB) (p < 0.01). DD treated with P associated with CSE did not differ from DD/CSE (p > 0.05). The NaF treatment associated with CSE recovered the bond strength values of SD/CSE and associated with CSE demonstrated lower µTBS than other groups, although significantly higher than DD (p < 0.05). P and CPP-ACP increased significantly the wettability of demineralized dentin (p < 0.05); etching acid improved wettability for all groups (p < 0.05), whilst NaF did not affect the wettability of demineralized dentin (p > 0.05). Morphological analysis of the dentin surface and dentin-resin interface revealed unique features of the applied remineralizing agent. The results indicated that self-assembling peptide P associated with SB and CPP-ACP associated with SB or CSE significantly enhanced the bond strength to demineralized dentin (p < 0.05). We conclude that by modifying the dentine surface and restoring conditions found on sound dentin, this can enhance the interfacial bonding.
Topics: Amino Acid Sequence; Biomechanical Phenomena; Calcium Phosphates; Dentin; Humans; Mechanical Phenomena; Minerals; Oligopeptides; Sodium Fluoride
PubMed: 29550716
DOI: 10.1016/j.jmbbm.2018.03.007 -
Journal of Dentistry Aug 2014To evaluate, in vitro, the effects of ionizing radiation on the mechanical and micro-morphological properties of enamel and dentin of permanent teeth. (Comparative Study)
Comparative Study
OBJECTIVES
To evaluate, in vitro, the effects of ionizing radiation on the mechanical and micro-morphological properties of enamel and dentin of permanent teeth.
METHODS
Enamel and dentin microhardness (n=12 hemi-sections) was evaluated at three depths (superficial, middle and deep) prior to (control) and after every 10Gy radiation dose up to a cumulative dose of 60Gy by means of longitudinal microhardness. Data were analyzed using two-way analysis of variance and Tukey's test at a significance level of 5%. Enamel and dentin morphology was assessed by scanning electron microscopy (SEM) for semi-quantitative analysis (n=8 hemi-sections). Data were analyzed using Kruskal-Wallis and Dunn's or Fisher exact tests at a significance level of 5%.
RESULTS
The application of ionizing radiation did not change the overall enamel microhardness, although an increase in superficial enamel microhardness was observed. The micro-morphological analysis of enamel revealed that irradiation did not influence rod structure but interprismatic structure became more evident. Dentin microhardness decreased after 10, 20, 30, 50 and 60Gy cumulative doses (p<0.05) compared with non-irradiated dentin, mainly in the middle portion of the tissue. The micro-morphological analysis revealed fissures in the dentin structure, obliterated dentinal tubules and fragmentation of collagen fibers after 30 and 60Gy cumulative doses.
CONCLUSIONS
Although ionizing radiation did not affect the enamel microhardness of permanent teeth as a whole, an increase in superficial enamel microhardness was observed. Dentin microhardness decreased after almost all radiation doses compared with the control, with the greatest reduction of microhardness in the middle depth region. The morphological alterations on enamel and dentin structures increased with the increase of the radiation dose, with a more evident interprismatic portion, presence of fissures and obliterated dentinal tubules, and progressive fragmentation of the collagen fibers.
CLINICAL SIGNIFICANCE
This study shows that irradiation affects microhardness and micro-morphology of enamel and dentin of permanent teeth. The effects of gamma irradiation on dental substrate might contribute to increased risk of radiation tooth decay associated with salivary changes, microbiota shift and high soft and carbohydrate-rich food intake.
Topics: Cobalt Radioisotopes; Collagen; Dental Enamel; Dentin; Dose Fractionation, Radiation; Hardness; Humans; In Vitro Techniques; Microscopy, Electron, Scanning; Molar; Radiotherapy Dosage; Radiotherapy, High-Energy
PubMed: 24887361
DOI: 10.1016/j.jdent.2014.05.011 -
Acta Biomaterialia Sep 2014Dentin contains 1-2μm diameter tubules extending from the pulp cavity to near the junction with enamel. Peritubular dentin (PTD) borders the tubule lumens and is...
Dentin contains 1-2μm diameter tubules extending from the pulp cavity to near the junction with enamel. Peritubular dentin (PTD) borders the tubule lumens and is surrounded by intertubular dentin (ITD). Differences in PTD and ITD composition and microstructure remain poorly understood. Here, a (∼200nm)(2), 10.1keV synchrotron X-ray beam maps X-ray fluorescence and X-ray diffraction simultaneously around tubules in 15-30μm thick bovine and equine specimens. Increased Ca fluorescence surrounding tubule lumens confirms that PTD is present, and the relative intensities in PTD and ITD correspond to carbonated apatite (cAp) volume fraction of ∼0.8 in PTD vs. 0.65 assumed for ITD. In the PTD near the lumen edges, Zn intensity is strongly peaked, corresponding to a Zn content of ∼0.9mgg(-1) for an assumed concentration of ∼0.4mgg(-1) for ITD. In the equine specimen, the Zn K-edge position indicates that Zn(2+) is present, similar to bovine dentin (Deymier-Black et al., 2013), and the above edge structure is consistent with spectra from macromolecules related to biomineralization. Transmission X-ray diffraction shows only cAp, and the 00.2 diffraction peak (Miller-Bravais indices) width is constant from ITD to the lumen edge. The cAp 00.2 average preferred orientation is axisymmetric (about the tubule axis) in both bovine and equine dentin, and the axisymmetric preferred orientation continues from ITD through the PTD to the tubule lumen. These data indicate that cAp structure does not vary from PTD to ITD.
Topics: Animals; Calcium; Cattle; Crystallography, X-Ray; Dentin; Fluorescence; Horses; Radiography; X-Ray Absorption Spectroscopy; Zinc
PubMed: 24911530
DOI: 10.1016/j.actbio.2014.05.027 -
BMC Oral Health Dec 2019Dentin hypersensitivity is a frequent finding especially in periodontitis patients. Conventional treatment aims for obstruction of dentin tubules by disabling liquid and... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Dentin hypersensitivity is a frequent finding especially in periodontitis patients. Conventional treatment aims for obstruction of dentin tubules by disabling liquid and osmotic fluctuation to and from the pulpal chamber. A novel bioglass-based desensitizer was shown to obstruct tubules and to resist periodic exposure to lactic acid. Whether this obstruction is resistant to brushing had not been tested so far. Accordingly, the present study aimed to assess dentin tubule obstruction after repeated acid exposure and brushing.
METHODS
Sixty dentin discs were cleaned with 17% EDTA, mounted into a pulp fluid simulator and randomly divided into 3 groups: No surface treatment in Group A, Seal&Protect® in group B and DentinoCer in group C. Discs were exposed to 0.1 M non-saturated lactic acid thrice and standardized brushing twice a day for 12 days. At baseline and after 2, 4 and 12 d samples were removed from the setting and prepared for top-view SEM analysis to assess tubule obstruction using the Olley score. Discs were then vertically cut and the section surface morphologically assessed using backscatter imaging. For both vertical and sectional surfaces EDX analysis was used to characterize the surface composition in the tubular and inter-tubular area.
RESULTS
Group A showed clean tubular lumina at all time points. From day 2 onwards dentin showed exposed collagen fibers. Group 2 initially showed a complete surface coverage that flattened out during treatment without ever exposing tubules. At baseline, samples of Group C displayed a complete homogeneous coverage. From day 2 on tubules entrances with obstructed lumen became visible. While on day 4 and 12 the dentin surface exposed collagen fibers the lumina remained closed. EDX analysis of the vertical and horizontal views showed that P and Ca were predominant elements in both the inter- and tubular dentin while Si peaks were found in the tubule plugs.
CONCLUSION
While group B displayed a packed layer on the surface during the whole investigation time group C samples lost their superficial layer within 48 h. Tubule plugs containing considerable Si proportions indicated previous presence of DentinoCer, while high Ca and P proportions suggest obturation by dentin-like material.
Topics: Biocompatible Materials; Ceramics; Dentin; Dentin Desensitizing Agents; Dentin Permeability; Dentin Sensitivity; Humans; Microscopy, Electron, Scanning
PubMed: 31805922
DOI: 10.1186/s12903-019-0962-7 -
Folia Biologica 2021Prematurely erupted teeth are rare in fullterm neonates and extremely rare in prematurely delivered infants. The aim of this study was to present macroscopic and...
Prematurely erupted teeth are rare in fullterm neonates and extremely rare in prematurely delivered infants. The aim of this study was to present macroscopic and scanning electron microscopy (SEM) investigations of prematurely erupted primary teeth of preterm very low birthweight (VLBW) and extremely low birthweight (ELBW) infants. Three preterm VLBW and ELBW infants with prematurely erupted lower incisors were examined. The dental examination assessed the type, location, clinical appearance, and degree of mobility of the prematurely erupted teeth. The structural appearance of enamel and dentin of three extracted and longitudinally sectioned prematurely erupted teeth was investigated with scanning electron microscopy (SEM). Lower incisors were rootless with hypermobility. The surface of enamel of the prematurely erupted primary teeth was hypoplastic and hypomineralized and had a typical "honeycomb" appearance in SEM. The aprismatic type of enamel was visible in some regions. The neonatal line separating the layer of prenatal enamel from postnatal enamel was observed. The enamel prisms were interconnected by interprismatic substances, and cross-striations of prisms were visible. Dentin presented a typical tubular character. The dentinal layer near the enamel dentin junction had Y-shaped branching of dentinal tubules. On the pulpal side, dentin had a globular character. The macroscopic and SEM investigations particularly revealed alterations in enamel, while the dentin of neonatal teeth had a nearly normal appearance.
Topics: Dentin; Humans; Incisor; Infant; Infant, Newborn; Infant, Premature; Microscopy, Electron, Scanning
PubMed: 35151238
DOI: No ID Found -
Dental Materials Journal Jun 2024This study investigates the effects of dentin's drying time, roughness, and curing modes of resin cement on bond strength. Forty human teeth were divided into eight...
This study investigates the effects of dentin's drying time, roughness, and curing modes of resin cement on bond strength. Forty human teeth were divided into eight groups based on three experimental factors: dentin's roughness by 240-or 600-grit SiC paper (coarse or fine), dentin wetness with air-drying time (5-s or 10-s), and Single Bond Universal adhesive's curing mode by co-curing with RelyX Ultimate cement or light-curing separately (co-curing or light-curing). The micro-tensile bond strength of fifteen resin-dentin stikcs per groups was measured. Failure mode and adhesive layers were observed using stereoscopic and confocal laser scanning microscopy, respectively. The curing mode of the adhesive layer affected the bond strength of the dentin-resin cement (p<0.05). In particular, the light-curing mode exhibited a significantly higher bond strength than the co-curing one (p<0.05). The bond strength between the resin cement and dentin was improved in the 5-s drying groups than in the 10-s drying groups.
Topics: Humans; Dentin; Surface Properties; Resin Cements; Tensile Strength; Dental Bonding; Materials Testing; Dentin-Bonding Agents; Microscopy, Confocal; Bisphenol A-Glycidyl Methacrylate; Dental Stress Analysis; Light-Curing of Dental Adhesives; Time Factors
PubMed: 38719583
DOI: 10.4012/dmj.2023-287 -
Journal of Indian Prosthodontic Society 2023To compare the effect of polymerization of resin-modified glass ionomer cement and dual-cure resin cement on the crystalline structure and to correlate it clinically...
Comparison and evaluation of the effect of polymerization of resin-modified glass ionomer cement and dual-cure resin cement on the crystalline structure of dentin using synchrotron X-ray diffraction and its clinical correlation with postoperative sensitivity.
AIM
To compare the effect of polymerization of resin-modified glass ionomer cement and dual-cure resin cement on the crystalline structure and to correlate it clinically with postoperative sensitivity.
SETTINGS AND DESIGN
The evaluation of crystalline strain in the dentin slabs was done using Synchrotron X-ray diffraction. The post operative sensitivity was measured clinically using Schiff's sensitivity scale.
MATERIALS AND METHODS
A total of 44 extracted and noncarious premolars were collected. Dentin slabs of dimensions 2 mm × 2 mm × 1.5 mm were prepared from the buccal aspect of the extracted teeth. The dentin slabs were then divided into two groups, Group A dual-cured resin cement and Group B resin-modified glass ionomer cement was applied. The dentin slabs first underwent synchrotron X-ray diffraction before and after the application of cement. Forty-two patients who were undergoing complete metal fixed prostheses on vital posterior abutments were selected. In this, 21 vital abutments were included in each group. Tooth preparation and fabrication of complete metal prostheses were done in the conventional manner and cemented using the 2 luting cements in Groups A and B, respectively. Dentinal hypersensitivity was measured using Schiff 's scale, postcementation, after 1 week and 1 month.
STATISTICAL ANALYSIS
Independent t-test was done for comparing the two cements in two cements in terms of lattice strain. Mann-Whitney U-test was done for comparing the cements with respect to dentinal hypersensitivity. Spearman's correlation coefficient was used for clinical correlation between dentinal hypersensitivity and crystalline strain.
RESULTS
The lattice strain generated in dual cure resin cement was higher than that in resin-modified glass ionomer cement and was statistically significant. Postcementation hypersensitivity was higher in dual-cured resin than resin-modified glass ionomer cement but was not statistically significant in the follow-up visits. Spearman's correlation coefficients did not reveal any significant clinical correlation between lattice strain and dentinal hypersensitivity.
CONCLUSION
Dual cure resin cements generate greater lattice strain as compared to resin modified glass ionomer cements.
Topics: Humans; Glass Ionomer Cements; Resin Cements; Polymerization; Synchrotrons; X-Ray Diffraction; Resins, Plant; Dentin
PubMed: 37102536
DOI: 10.4103/jips.jips_84_22 -
TheScientificWorldJournal 2021This study evaluated the influence of bioactive plant extracts as dentin biomodifying agents to improve the longevity of bonded restorations. For that, plant extracts...
OBJECTIVE
This study evaluated the influence of bioactive plant extracts as dentin biomodifying agents to improve the longevity of bonded restorations. For that, plant extracts were applied to the dentin surface prior to the adhesive system.
MATERIALS AND METHODS
Bovine incisors were ground flat to obtain 2 mm thick slices in which conical preparations were made ( = 10). Tannin-containing plant extracts were applied to dentin before the application of the restorative system, as follows: control group (untreated, CTL), chlorhexidine 0.12% (CHX), mastruz ( MTZ), cat's claw ( CTC), guarana (, GUA), galla chinensis (, GCH), and tannic acid (extracted from , TNA). The push-out bond strength test was conducted (0.5 mm/min). Dentin biomodification was assessed by the modulus of elasticity and mass change in bovine tooth sections (0.5 × 1.7 × 7.0 mm). The dentin staining after extract treatments of dentin slices was compared. The dentin surface wettability was also evaluated by means of the contact angles of the adhesive system with the dentin surface and compared with the untreated control group. Data were subjected to ANOVA/Tukey's test ( = 0.05).
RESULTS
The bond strength of the restoratives to dentin was not significantly improved by the plant extracts, irrespective of the evaluation time ( > 0.05). Except for TNA, the elastic modulus of demineralized dentin significantly reduced after treatment with the plant extracts ( < 0.05). The dentin staining correlated with the tannin content of the extracts. The contact angle was significantly reduced when treated with CTC, GCH, and TNA.
CONCLUSIONS
The tannin-containing extracts had a questionable effect on the longevity of bonded restorations. The dentin modulus was negatively affected by the extract treatments. Although some of the extracts changed the contact angle, which seems to improve the adhesive monomer permeation, the tannin-rich plant extract application prior to adhesive application was proven to be clinically unfeasible due to dentin staining.
Topics: Dental Bonding; Dentin; Humans; Plant Extracts; Tannins
PubMed: 34220363
DOI: 10.1155/2021/1614643 -
Antimicrobial Efficacy of Triple Antibiotic-eluting Polymer Nanofibers against Multispecies Biofilm.Journal of Endodontics Sep 2017The elimination of microbial flora in cases of immature permanent teeth with necrotic pulp is both key and a challenging goal for the long-term success of regenerative...
The elimination of microbial flora in cases of immature permanent teeth with necrotic pulp is both key and a challenging goal for the long-term success of regenerative therapy. Recent research has focused on the development of cell-friendly intracanal drug delivery systems. This in vitro study aimed to investigate the antimicrobial action of 3-dimensional (3D) tubular-shaped triple antibiotic-eluting nanofibrous constructs against a multispecies biofilm on human dentin. Polydioxanone polymer solutions, antibiotic-free or incorporated with metronidazole, ciprofloxacin, and minocycline, were electrospun into 3D tubular-shaped constructs. A multispecies biofilm consisting of Actinomyces naeslundii, Streptococcus sanguinis, and Enterococcus faecalis was forced inside the dentinal tubules via centrifugation in a dentin slice in vitro model. The infected specimens were exposed to 2 experimental groups (ie, 3D tubular-shaped triple antibiotic-eluting constructs and triple antibiotic paste [TAP]) and 2 control groups (7-day biofilm untreated and antibiotic-free 3D tubular-shaped constructs). Biofilm elimination was quantitatively analyzed with confocal laser scanning microscopy. Confocal laser scanning microscopic (CLSM) analysis showed a dense population of viable (green) bacteria adhered to dentin and penetrated into the dentinal tubules. Upon 3D tubular-shaped triple antibiotic-eluting nanofibrous construct exposure, nearly complete elimination of viable bacteria on the dentin surface and inside the dentinal tubules was shown in the CLSM images, which was similar (P < .05) to the bacterial death promoted by the TAP group but significantly greater when compared with both the antibiotic-free 3D tubular-shaped constructs and the control (saline). The proposed 3D tubular-shaped antibiotic-eluting construct showed pronounced antimicrobial effects against the multispecies biofilm tested and therefore holds significant clinical potential as a disinfection strategy before regenerative endodontics.
Topics: Anti-Bacterial Agents; Biofilms; Ciprofloxacin; Dentin; Metronidazole; Minocycline; Nanofibers; Polymers
PubMed: 28778504
DOI: 10.1016/j.joen.2017.06.009