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Scientific Reports Jun 2024Notum is a direct target of Wnt/β-catenin signaling and plays a crucial role as a Wnt inhibitor within a negative feedback loop. In the tooth, Notum is known to be...
Notum is a direct target of Wnt/β-catenin signaling and plays a crucial role as a Wnt inhibitor within a negative feedback loop. In the tooth, Notum is known to be expressed in odontoblasts, and severe dentin defects and irregular tooth roots have been reported in Notum-deficient mice. However, the precise expression pattern of Notum in early tooth development, and the role of Notum in crown and root patterns remain elusive. In the present study, we identified a novel Notum expression in primary enamel knot (EK), secondary EKs, and dental papilla during tooth development. Notum-deficient mice exhibited enlarged secondary EKs, resulting in broader cusp tips, altered cusp patterns, and reduced concavity in crown outline. These alterations in crown outline led to a reduction in cervical tongue length, thereby inducing root fusion in Notum-deficient mice. Overall, these results suggest that the secondary EK size, regulated by the Wnt/Notum negative feedback loop, has a significant impact on the patterns of crown and root during tooth morphogenesis.
Topics: Animals; Mice; Gene Expression Regulation, Developmental; Mice, Knockout; Molar; Odontogenesis; Receptors, G-Protein-Coupled; Tooth Crown; Tooth Root; Wnt Signaling Pathway
PubMed: 38871845
DOI: 10.1038/s41598-024-64340-w -
Archives of Oral Biology Sep 2024Tooth growth and wear are commonly used tools for determining the age of mammals. The most speciose order of marsupials, Diprotodontia, is characterised by a pair of...
OBJECTIVE
Tooth growth and wear are commonly used tools for determining the age of mammals. The most speciose order of marsupials, Diprotodontia, is characterised by a pair of procumbent incisors within the lower jaw. This study examines the growth and wear of these incisors to understand their relationship with age and sex.
DESIGN
Measurements of mandibular incisor crown and root length were made for two sister species of macropodid (kangaroos and wallabies); Macropus giganteus and Macropus fuliginosus. Histological analysis examined patterns of dentine and cementum deposition within these teeth. Broader generalisability within Diprotodontia was tested using dentally reduced Tarsipes rostratus - a species disparate in body size and incisor function to the studied macropodids.
RESULTS
In the macropodid sample it is demonstrated that the hypsodont nature of these incisors makes measurements of their growth (root length) and wear (crown length) accurate indicators of age and sex. Model fitting finds that root growth proceeds according to a logarithmic function across the lifespan, while crown wear follows a pattern of exponential reduction for both macropodid species. Histological results find that secondary dentine deposition and cementum layering are further indicators of age. Incisor measurements are shown to correlate with age in the sample of T. rostratus.
CONCLUSIONS
The diprotodontian incisor is a useful tool for examining chronological age and sex, both morphologically and microstructurally. This finding has implications for population ecology, palaeontology and marsupial evolution.
Topics: Animals; Incisor; Marsupialia; Female; Male; Tooth Root; Macropodidae; Tooth Crown; Dental Cementum; Age Determination by Teeth; Tooth Wear; Dentin
PubMed: 38870611
DOI: 10.1016/j.archoralbio.2024.106018 -
BMC Oral Health Jun 2024Surface tension and contact angle properties, which play a crucial role in determining the effectiveness of irrigation solutions in penetrating dentin surfaces and... (Comparative Study)
Comparative Study
BACKGROUND
Surface tension and contact angle properties, which play a crucial role in determining the effectiveness of irrigation solutions in penetrating dentin surfaces and dentin tubules, are highly important for the development of new irrigation solutions and their preferences. The aim of the current study was to compare the surface tension and contact angle properties of different irrigation solutions used in endodontics, both on the dentin surface and within dentin tubules.
METHODS
In this study, the contact angles and surface tensions of 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), 5% boric acid (BA), 0.02% hypochlorous acid (HOCl), 0.2% chlorine dioxide (ClO), Biopure MTAD, QMix solutions, and distilled water (control group) were measured. Measurements were conducted using a goniometer device (Attension Theta Lite Tensiometer, Biolin Scientific, USA), employing the sessile drop method for contact angle measurements on pre-prepared dentin surfaces, and the pendant drop method for surface tension.
RESULTS
Contact angle measurements revealed no statistically significant differences between the contact angle values of MTAD, ClO, and CHX or between NaOCl, QMix, BA, and HOCl (p > 0.05). However, EDTA exhibited a significantly greater contact angle than did MTAD, ClO, CHX, NaOCl, QMix, BA, and HOCl (p < 0.05). Furthermore, the contact angle of dentin with distilled water was greater than that with all other solutions tested (p < 0.05). Surface tension measurements revealed that the surface tension values of QMix and MTAD were statistically similar (p > 0.05). CHX exhibited lower surface tension than distilled water and HOCl (p < 0.05), and it also had lower surface tension than ClO, NaOCl, and BA (p < 0.05). Additionally, the surface tension of the samples treated with EDTA was greater than that of all other solutions tested (p < 0.05).
CONCLUSION
The direct linear relationship between the surface tension of liquids and contact angles on different surfaces may not always hold true, and these values should be considered independently for each solution on various surfaces. Considering the contact angles and surface tension properties of irrigation solutions with root canal dentin, it can be suggested for clinical use that ClO could be recommended over NaOCl, and similarly, BA could be recommended over EDTA.
Topics: Root Canal Irrigants; Dentin; Surface Tension; Humans; Sodium Hypochlorite; Edetic Acid; Hypochlorous Acid; Surface Properties
PubMed: 38867263
DOI: 10.1186/s12903-024-04453-w -
Cureus May 2024Silver amalgam, glass ionomer, resin-modified glass ionomer, compomers, light polymerized hybrid composite resin, and hybrid glass ionomer are among the most frequent...
INTRODUCTION
Silver amalgam, glass ionomer, resin-modified glass ionomer, compomers, light polymerized hybrid composite resin, and hybrid glass ionomer are among the most frequent restorative materials used as cavity-based or post-endodontics. Thus, to meet the needs of both patients and dentists, Cention N reimagines the traditional filling by integrating bulk placement, ion release, and durability into a dual-curing, aesthetically pleasing solution. Hoewver, we do not have enough information from studies comparing this hybrid restorative material's shear bond strengths to dentin to draw any firm conclusions. Cention N, zirconomer, and Vitremer are three hybrid tooth-colored restorative materials that were evaluated for their shear bond strength to dentin. This research aimed to compare and evaluate these materials.
METHODOLOGY
The purpose of this research was to use a universal Instron machine to measure the shear bond stress of three distinct hybrid tooth-colored restorative materials in relation to dentin. The research samples consisted of 45 extracted lower first premolars from humans. The teeth were then assigned into three groups of 15 samples each according to different color acrylic resin blocks, namely, group A (pink acrylic blocks), which had Cention in cement; group B (white acrylic blocks), which has zirconomer cement; and group C (violet acrylic blocks), which had Vitremer cement.
RESULTS
There was no statistically significant difference between the three groups and the normal distribution, as shown by the negligible values in the tests involving the three groups. Put simply, each of the three categories exhibits data that follows a normal distribution. This allows for further data analysis to be conducted using the parametric test of significance.
CONCLUSION
The shear bond strength of hybrid glass ionomer restorative materials has to be further investigated in both laboratory and living organism settings.
PubMed: 38864074
DOI: 10.7759/cureus.60123 -
Frontiers in Cell and Developmental... 2024Epigenetics refers to the mechanisms such as DNA methylation and histone modification that influence gene expression without altering the DNA sequence. These epigenetic... (Review)
Review
Epigenetics refers to the mechanisms such as DNA methylation and histone modification that influence gene expression without altering the DNA sequence. These epigenetic modifications can regulate gene transcription, splicing, and stability, thereby impacting cell differentiation, development, and disease occurrence. The formation of dentin is intrinsically linked to the odontogenic differentiation of dental pulp stem cells (DPSCs), which are recognized as the optimal cell source for dentin-pulp regeneration due to their varied odontogenic potential, strong proliferative and angiogenic characteristics, and ready accessibility Numerous studies have demonstrated the critical role of epigenetic regulation in DPSCs differentiation into specific cell types. This review thus provides a comprehensive review of the mechanisms by which epigenetic regulation controls the odontogenesis fate of DPSCs.
PubMed: 38863943
DOI: 10.3389/fcell.2024.1394582 -
Clinical Oral Investigations Jun 2024Fixed orthodontic appliances may increase the risk for caries and white spot lesions. The aim of this retrospective study was to determine the long-term associations...
OBJECTIVES
Fixed orthodontic appliances may increase the risk for caries and white spot lesions. The aim of this retrospective study was to determine the long-term associations between both in orthodontic patients.
MATERIALS AND METHODS
103 patients aged 36.6 ± 6.5 years whose fixed appliance orthodontic treatment had finished at least 15 years ago were included. Current clinical data and photographs (T3), panoramic x-ray and photographs from before treatment (T0), after debonding (T1) and at 2-year follow-up (T2) were available. Parameters of interest were dentine caries, "Missing/Filled Teeth" (MFT), "White Spot Lesion" (WSL) index and "Periodontal Screening and Recording" index (PSR; T3 only).
RESULTS
At T0, 30.4% had no caries experience decreasing to 25.6%, 22.4% and 6.8% at T1, T2 and T3 resp. The median MFT (95% CI) at T0, T1, T2 and T3 was 2 (1;3), 3 (2;4), 3 (2;4) and 7 (6;9) resp. increasing significantly at each time point (p < 0.001 each); 30.1% had WSL at debonding. Patients with caries experience at T0 had a 2.4-fold increased risk of WSL at debonding. Dentine caries, caries experience and WSL at T1 were significantly associated with incident caries at T2, but not at T3. PSR at T3 had a significant association with previous caries incidence and WSL.
CONCLUSIONS
Caries experience prior to orthodontic treatment may constitute a risk indicator for WSL, and caries experience and WSL at its end for caries incidence in the near term.
CLINICAL RELEVANCE
Present caries and WSL may help identifying orthodontic patients with special need for prevention and counselling.
Topics: Humans; Dental Caries; Retrospective Studies; Male; Female; Adult; Radiography, Panoramic; Risk Factors; Orthodontic Appliances, Fixed; DMF Index
PubMed: 38861170
DOI: 10.1007/s00784-024-05752-w -
BMC Oral Health Jun 2024This systematic review aims to comparatively analyse the amount of dentin removal by free hand and static guided endodontics with dynamic navigation system (DNS) in...
OBJECTIVE
This systematic review aims to comparatively analyse the amount of dentin removal by free hand and static guided endodontics with dynamic navigation system (DNS) in endodontic access cavity preparation.
METHODS
The systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Based on the structured PICO framework of "Comparative evaluation of dynamic navigation system (I) to freehand (C) and static guided endodontics (C) in endodontic access cavity preparation on the preservation of tooth structure (O) when assessed on permanent human teeth (P)", the keywords were formulated and the articles were retrieved from three databases namely PubMed, Scopus and Embase, based on the keywords from the time of inception of DNS till June 2023. The risk of bias assessment was done using a modified Joanne Briggs Institute checklist, which evaluated domains such as randomisation, sample size, image acquisition using CBCT, angulation, accuracy and time taken. As the data was heterogenous, a quantitative meta-analysis was not performed.
RESULTS
Initially, 174 articles were retrieved from the three databases, 30 duplicates were removed, after title check 108 articles were excluded and following abstract check only 10 articles qualified for full text analysis. On reviewing the 10 full text articles, 5 articles were excluded and the remaining 5 articles were subjected to the risk of bias analysis which showed that 2 articles displayed low risk of bias and three articles showed high risk of bias. The RoB analysis revealed that only 2 studies evaluated the preservation of dentin in terms of accuracy, angulation and time taken proving the increased precision with minimal loss of tooth structure using DNS. In both the studies, DNS proved to be superior to free hand technique in terms of precision, accuracy and efficiency in locating the canals during access cavity preparation with maximal preservation of tooth structure.
CONCLUSION
With the minimal literature evidences, the present systematic review highlights maximal preservation of dentin using DNS. However, further invitro and invivo studies comparing the free hand, static guided endodontics to DNS must be carried out for its translation into clinical practice.
CLINICAL SIGNIFICANCE
Dynamic navigation system provides maximal preservation of dentin during access cavity preparation.
Topics: Humans; Dentin; Root Canal Preparation
PubMed: 38858636
DOI: 10.1186/s12903-024-04450-z -
Scientific Reports Jun 2024The purpose of this study was to evaluate the fatigue survival of 5Y-PSZ zirconia infiltrated with an experimental glass and bonded onto dentin analogues. Disc-shaped...
The purpose of this study was to evaluate the fatigue survival of 5Y-PSZ zirconia infiltrated with an experimental glass and bonded onto dentin analogues. Disc-shaped specimens of a 5Y-PSZ (Katana UTML Kuraray Noritake) were cemented onto dentin analogs (NEMA G10) and divided into four groups (n = 15): Zctrl Group (control, without infiltration); Zglz Group (Glaze, compression surface); Zinf-comp Group (Experimental Glass, compression surface); Zinf-tens Group (Experimental Glass, tension surface). Surface treatments were varied. Cyclic fatigue loading, oblique transillumination, stereomicroscope examination, and scanning electron microscopy were performed. Fatigue data were analyzed (failure load and number of cycles) using survival analysis (Kaplan-Meier and Log-Rank Mantel-Cox). There was no statistically significant difference in fatigue survival between the Zglz, Zctrl, and Zinf-comp groups. The Zinf-tens group presented a significantly higher failure load when compared to the other groups and exhibited a different failure mode. The experimental glass effectively infiltrated the zirconia, enhancing structural reliability, altering the failure mode, and improving load-bearing capacity over more cycles, particularly in the group where the glass was infiltrated into the tensile surface of the zirconia. Glass infiltration into 5Y-PSZ zirconia significantly enhanced structural reliability and the ability to withstand loads over an increased number of cycles. This approach has the potential to increase the durability of zirconia restorations, reducing the need for replacements and save time and resources, promoting efficiency in clinical practice.
Topics: Zirconium; Glass; Dentin; Materials Testing; Humans; Microscopy, Electron, Scanning; Surface Properties
PubMed: 38858417
DOI: 10.1038/s41598-024-64110-8 -
Biomedical Optics Express May 2024Polarized light microscopy (PLM) is an established method in dental histology for investigating the ultrastructure and carious process of teeth. This study introduces a...
Polarized light microscopy (PLM) is an established method in dental histology for investigating the ultrastructure and carious process of teeth. This study introduces a novel approach for measuring the degree of polarization (DOP) in a modified PLM setup and uses the DOP to assess the changes of the optical properties of enamel and dentin due to caries. The validation is provided by a comparison with complementary imaging methods, i.e. standard PLM and µCT. The results show that demineralization is reliably displayed by the DOP in accordance with the common imaging methods, and that this quantitative analysis of depolarization allows the characterization of the different pathohistological zones of caries.
PubMed: 38855694
DOI: 10.1364/BOE.514904 -
The Journal of Prosthetic Dentistry Jun 2024Although bonding is important for long-term clinical success, studies on the bonding of additively manufactured ceramics are sparse.
STATEMENT OF PROBLEM
Although bonding is important for long-term clinical success, studies on the bonding of additively manufactured ceramics are sparse.
PURPOSE
The purpose of this in vitro study was to determine the influence of manufacturing methods, additive (LCM) versus subtractive (CAM). and ceramic materials, zirconia (ZrO) and lithium disilicate (LiSi), on the tensile bond strength (TBS), failure mode, and surface roughness of ceramics.
MATERIAL AND METHODS
A total of 240 ceramic specimens (n=60/group; 2×2×10 mm) were prepared. Two additively manufactured (LCM-printed) ceramics, LiSi and ZrO (Lithoz), subtractively manufactured LiSi (IPS e.max CAD), and subtractively manufactured ZrO (KATANA Zirconia HTML PLUS) were evaluated. From each material, 40 specimens were bonded together (n=20 ceramic-ceramic specimens/group), and 20 specimens were bonded to equally sized human dentin specimens (n=20 ceramic-dentin specimens/group). The ZrO specimens were airborne-particle abraded (AlO, 50 µm, 0.1 MPa), and the LiSi specimens were etched with hydrofluoric acid. Then, a universal primer (Monobond Plus) was applied. After the dentin was coated with an etch-and-rinse adhesive (Syntac Classic), the specimens were bonded with luting composite resin (Variolink Esthetic DC), light polymerized for 40 seconds, thermally aged (10 000 cycles between 5 °C and 55 °C), tested for TBS, and statistically analyzed (1- and 3-way ANOVA and Weibull analysis). The ceramic surface was examined with scanning electron microscopy, and surface roughness was measured with digital microscopy before and after surface pretreatment.
RESULTS
TBS varied between 5.88 ±2.22 MPa and 6.34 ±2.26 MPa in the ceramic-dentin groups and 12.40 ±1.56 MPa and 18.82 ±5.92 MPa in the ceramic-ceramic groups. No significant difference was observed regarding the manufacturing method and material for different bonding conditions (P>.05). Additive and subtractive LiSi showed the highest reliability with m=18.27. The ceramic-ceramic specimens failed cohesively in the luting composite resin, whereas the ceramic-dentin specimens failed adhesively.
CONCLUSIONS
The manufacturing method and material used had little effect on bond strength values or surface properties. The recently introduced printed materials performed similarly to conventionally milled materials.
PubMed: 38853056
DOI: 10.1016/j.prosdent.2024.04.002