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Dental Materials : Official Publication... Jun 2024This study aimed to determine the crystalline phase composition of 3-6 mol% yttria-stabilized zirconia (3-6YSZ), specifically investigating the presence of tetragonal...
OBJECTIVES
This study aimed to determine the crystalline phase composition of 3-6 mol% yttria-stabilized zirconia (3-6YSZ), specifically investigating the presence of tetragonal (t), cubic (c), and/or additional yttria-rich tetragonal (t') phase.
METHODS
Laboratory-fabricated specimens comprising 3-5YSZ, resembling translucent dental zirconia ceramics (TZ specimens), and a blend of 3YSZ and 8YSZ, representing a c-phase reference, were prepared. Additionally, 25 dental zirconia products stabilized with 3-6 mol% yttria were analyzed. Whole X-ray diffraction (XRD) patterns were obtained for Rietveld analysis, complemented by fine scanning in the 2θ region from 72º to 76º for qualitative phase analysis. Moreover, yttria concentrations in each specimen were determined using X-ray fluorescence (XRF) spectroscopy.
RESULTS
In the 2θ region from 72º to 76º, TZ and dental zirconia product specimens displayed four peaks attributed to t- and t'-phases, but the c-phase peak was absent. Rietveld analysis of the whole XRD patterns, utilizing a t-t' model, demonstrated the t-phase fraction ranging from 86 mass% in 3YSZ to 11 mass% in 6YSZ. Rietveld analysis appeared reliable, as the yttria contents calculated based on lattice parameters aligned well with those measured by XRF. This study established that dental 3-6YSZ consisted of yttria-lean t- and yttria-rich t'-phases.
SIGNIFICANCE
The present study enhances understanding of the crystalline structure of dental zirconia ceramics. Future crystallographic analyses of these ceramics should consider the presence of t- and t'-phases.
PubMed: 38942711
DOI: 10.1016/j.dental.2024.06.027 -
European Journal of Dentistry Jun 2024The proper closure of the access cavity between appointments during endodontic treatment is paramount and relies on temporary fillings. This systematic review evaluates...
The proper closure of the access cavity between appointments during endodontic treatment is paramount and relies on temporary fillings. This systematic review evaluates the effectiveness of zinc oxide-based materials and glass-ionomer cement (GIC) as temporary coronal sealers after root canal treatment in extracted human teeth. Three databases were searched to identify randomized clinical trials that examined the sealing properties of various temporary sealing materials using dyes or stains as indicators. A total of seven studies that fulfilled the eligibility criteria were critically analyzed. These indicated significant variations in the relative sealing ability of the coronal breach of endodontically treated teeth, either by zinc oxide or GIC-based materials. While GIC-based material (e.g., Fuji IX and Fuji II) exhibited superior sealing of single-rooted teeth, zinc oxide-based material (e.g., Cavit, Coltosol, Caviton) also showed promising attributes. Resin-modified GIC formulations displayed enhanced physical properties, yet challenges related to adhesive failure and shrinkage during polymerization were observed. Zinc oxide-based materials have demonstrated superior coronal sealing effectiveness over certain GIC in controlled settings. Their premixed nature ensures consistent application and hygroscopic properties improve cavity sealing. However, the focus on dye penetration tests for microleakage may not fully represent the risk of bacterial infiltration. Thus, studies are crucial for validating these findings in clinical contexts.
PubMed: 38942056
DOI: 10.1055/s-0044-1782695 -
European Journal of Dentistry Jun 2024This study evaluated surface roughness, biaxial flexural strength, and phase transformation of 5Y-PSZ after grinding and polishing with different protocols.
Effect of Grinding and Polishing Protocols on Surface Roughness, Flexural Strength, and Phase Transformation of High-Translucent 5 mol% Yttria-Partially Stabilized Zirconia.
OBJECTIVES
This study evaluated surface roughness, biaxial flexural strength, and phase transformation of 5Y-PSZ after grinding and polishing with different protocols.
MATERIAL AND METHODS
Two commercial 5Y-PSZ, Lava Esthetic (L) and Cercon xt (C), were used and divided into 3 groups: LC and CC represented unpolished control groups; LE and CE were polished with protocol I (EVE DIASYNT® PLUS HP following with EVE DIACERA RA); and LJ and CJ were polished with protocol II (Superfine diamond bur following with Jota ZIR Gloss polishing kit). Surface roughness was evaluated after polishing step-by-step with a contact-type profilometer. After high-gross polishing, the specimens were subjected to biaxial flexural strength test, crystallographic microstructure analysis using an X-ray diffractometer (XRD), and surface micro-topography using scanning electron microscopy (SEM).
STATISTICAL ANALYSIS
Surface roughness differences after each step and biaxial flexural strength between groups were evaluated with one-way ANOVA, followed by Bonferroni post-hoc analysis. Changes in surface roughness across four different time points within groups were assessed using one-way repeated measures ANOVA, followed by Bonferroni post-hoc analysis.
RESULTS
After high-gross polishing, both polishing protocols showed significantly lower surface roughness than the grinding group ( < 0.05). The LE and CE groups exhibited the highest surface roughness values, which were significant differences from the LJ and CJ groups ( < 0.05). The LE group showed significantly lower biaxial flexural strength compared to the LC group ( < 0.05). However, there was no statistically significant difference in the CE and CJ groups compared to the control group ( > 0.05). Furthermore, all polishing protocols did not change the phase transformation of zirconia.
CONCLUSION
Polishing protocol II provided a smoother surface than the protocol I after high-gross polishing, while the biaxial flexural strength of materials remained unaffected.
PubMed: 38942054
DOI: 10.1055/s-0044-1787001 -
European Journal of Dentistry Jun 2024This study aims to investigate DSM 17938's antibiofilm effects on and , common causes of alveolar osteitis. It seeks topical alternatives to prevent this condition...
OBJECTIVES
This study aims to investigate DSM 17938's antibiofilm effects on and , common causes of alveolar osteitis. It seeks topical alternatives to prevent this condition posttooth extraction. The secondary objective is to assess these effects under different pH conditions (pH 4.5 and pH 7), mimicking oral cavity saliva pH dynamics.
MATERIALS AND METHODS
Ethical approval was secured for the saliva collection process involving five healthy adult participants who had undergone wisdom tooth extraction. Saliva samples were diligently collected on the 7th day post-surgery. The unstimulated saliva underwent a series of treatments, including the addition of phenylmethylsulfonyl fluoride (PMSF), pH adjustments, centrifugation, and filtration. The pH levels were re-measured, and subsequent adjustments were made to achieve pH values of 4.5 or 7. DSM 17938, with a concentration of 1×10 colony-forming units (CFU) per 5 drops, was utilized in the study. Biofilm testing involved incubating saliva samples with varying pH (4.5 or 7) alongside bacterial suspensions (, or a mixed species). The Interlac suspension was introduced, and plates were anaerobically incubated for 24 hours. Biofilm results were obtained using a spectrometer. The test is conducted in triplicate.
STATISTICAL ANALYSIS
To scrutinize the impact of pH on biofilm development, the acquired data underwent a two-way ANOVA test in SPSS as part of the statistical analysis. A significance level of <0.05 was used to determine statistical significance.
RESULTS
DSM 17938 significantly reduced biofilm formation across bacterial strains ( = 0.000). Statistical analysis indicated a significant impact of pH on biofilm development ( = 0.000) compared to no saliva samples, with higher formation observed under acidic conditions (pH 4.5). However, the pH levels of 4.5 and 7 did not result in significantly different bacterial biofilm formation ( = 0.529).
CONCLUSION
This research highlights DSM 17938's potency in inhibiting biofilm formation of and . Salivary pH variations significantly influence biofilm development, emphasizing the need to consider pH when assessing probiotic effectiveness. Despite limitations in saliva sample sterilization, this study provides valuable insights into alternative approaches for preventing alveolar osteitis. Further research should explore clinical applications and refine sterilization methods for more accurate results.
PubMed: 38942052
DOI: 10.1055/s-0044-1786846 -
The Lancet. Rheumatology Jun 2024Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a proinflammatory cytokine overproduced in several inflammatory and autoimmune diseases, including axial...
Granulocyte-macrophage colony-stimulating factor neutralisation in patients with axial spondyloarthritis in the UK (NAMASTE): a randomised, double-blind, placebo-controlled, phase 2 trial.
BACKGROUND
Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a proinflammatory cytokine overproduced in several inflammatory and autoimmune diseases, including axial spondyloarthritis. Namilumab is a human IgG1 monoclonal anti-GM-CSF antibody that potently neutralises human GM-CSF. We aimed to assess the efficacy of namilumab in participants with moderate-to-severe active axial spondyloarthritis.
METHODS
This proof-of-concept, randomised, double-blind, placebo-controlled, phase 2, Bayesian (NAMASTE) trial was done at nine hospitals in the UK. Participants aged 18-75 years with axial spondyloarthritis, meeting the Assessment in SpondyloArthritis international Society (ASAS) criteria and the ASAS-defined MRI criteria, with active disease as defined by a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), were eligible. Those who had inadequately responded or had intolerance to previous treatment with an anti-TNF agent were included. Participants were randomly assigned (6:1) to receive subcutaneous namilumab 150 mg or placebo at weeks 0, 2, 6, and 10. Participants, site staff (except pharmacy staff), and central study staff were masked to treatment assignment. The primary endpoint was the proportion of participants who had an ASAS ≥20% improvement (ASAS20) clinical response at week 12 in the full analysis set (all randomly assigned participants). This trial is registered with ClinicalTrials.gov (NCT03622658).
FINDINGS
From Sept 6, 2018, to July 25, 2019, 60 patients with moderate-to-severe active axial spondyloarthritis were assessed for eligibility and 42 were randomly assigned to receive namilumab (n=36) or placebo (n=six). The mean age of participants was 39·5 years (SD 13·3), 17 were women, 25 were men, 39 were White, and seven had previously received anti-TNF therapy. The primary endpoint was not met. At week 12, the proportion of patients who had an ASAS20 clinical response was lower in the namilumab group (14 of 36) than in the placebo group (three of six; estimated between-group difference 6·8%). The Bayesian posterior probability η was 0·72 (>0·927 suggests high clinical significance). The rates of any treatment-emergent adverse events in the namilumab group were similar to those in the placebo group (31 vs five).
INTERPRETATION
Namilumab did not show efficacy compared with placebo in patients with active axial spondyloarthritis, but the treatment was generally well tolerated.
FUNDING
Izana Bioscience, NIHR Oxford Biomedical Research Centre (BRC), NIHR Birmingham BRC, and Clinical Research Facility.
PubMed: 38942047
DOI: 10.1016/S2665-9913(24)00099-7 -
Journal of the Mechanical Behavior of... Jun 2024Tooth extraction is a common clinical procedure with biomechanical factors that can directly influence patient outcomes. Recent development in atraumatic extraction...
BACKGROUND AND OBJECTIVE
Tooth extraction is a common clinical procedure with biomechanical factors that can directly influence patient outcomes. Recent development in atraumatic extraction techniques have endeavoured to improve treatment outcomes, but the characterization of extraction biomechanics is sparse. An axisymmetric inverse finite element (FE) approach is presented to represent the biomechanics of vertical atraumatic tooth extraction in an ex-vivo swine model.
METHODS
Geometry and boundary conditions from the model are determined to match the extraction of swine incisors in a self-aligning ex vivo extraction experiment. Material parameters for the periodontal ligament (PDL) model are determined by solving an inverse FE problem using clusters of data obtained from 10 highly-controlled mechanical experiments. A seven-parameter visco-hyperelastic damage model, based on an Arruda-Boyce framework, is used for curve fitting. Three loading schemes were fit to obtain a common set of material parameters.
RESULTS
The inverse FE results demonstrate good predictions for overall force-time curve shape, peak force, and time to peak force. The fit model parameters are sufficiently consistent across all three cases that a coefficient-averaged model was taken that compares well to all three cases. Notably, the initial modulus ,u, converged across trials to an average value of 0.472 MPa with an average viscoelastic constant g of 0.561.
CONCLUSIONS
The presented model is found to have consistent parameters across loading cases. The capability of this model to represent the fundamental mechanical characteristics of the dental complex during vertical extraction loading is a significant advancement in the modelling of extraction procedures. Future work will focus on verifying the model as a predictive design tool for assessing new loading schemes in addition to investigating its applications to subject-specific problems.
PubMed: 38941913
DOI: 10.1016/j.jmbbm.2024.106641 -
Clinical Oral Investigations Jun 2024The purpose of this prospective cohort study is to evaluate the effect of peri-implant phenotype (PPh) on the severity of peri-implant diseases and the results of...
OBJECTIVES
The purpose of this prospective cohort study is to evaluate the effect of peri-implant phenotype (PPh) on the severity of peri-implant diseases and the results of non-surgical mechanical treatment (NSMT), along with calprotectin (CLP) and MMP-8(matrix metalloproteinase-8) levels.
MATERIALS AND METHODS
77 implants from 39 patients were included. The implants were categorized Group-1(peri-implant mucositis), Group-2(peri-implantitis).Baseline (0. Month-PrT) clinical parameters (PD, GI, PI, BOP, CAL) and radiographic bone loss were documented, and peri-implant crevicular fluid (PICF) samples were collected. Various intruments and methodologies were employed to assess PPh components (mucosa thickness, supracrestal tissue height, keratinized mucosa) and peri-implant attached mucosa (AM). NSMT was applied to diseased implant sites. All clinical parameters were reassessed again by taking PICF samples at the 6th month-after treatment (PT). In PICF samples obtained from both groups, MMP-8 and CLP levels were evaluated using the ELISA test.
RESULTS
PrT-PD,PrT-GI,PrT-CAL and PrT-BOP percentage values in Group-2 were significantly higher than Group-1.PrT-PD,PrTPI scores are significantly higher in thin biotype implants. All components of the PPh and AM were significantly lower in thin biotype. Intra-group time-dependent changes of MMP-8 and CLP were significant in both groups (p < 0.05). When the relationship between thin and thick biotype and biochemical parameters was evaluated, the change in PrT-PT didn't show a significant difference (p > 0.05).
CONCLUSIONS
PPh plays a role in influencing the severity of peri-implant diseases. However, the impact of phenotype on NSMT outcomes was similar in both groups.
CLINICAL RELEVANCE
The PPh should be considered when planning implant surgery.
Topics: Humans; Matrix Metalloproteinase 8; Female; Prospective Studies; Peri-Implantitis; Male; Middle Aged; Phenotype; Gingival Crevicular Fluid; Leukocyte L1 Antigen Complex; Dental Implants; Enzyme-Linked Immunosorbent Assay; Biomarkers; Stomatitis; Periodontal Index; Adult; Aged
PubMed: 38940878
DOI: 10.1007/s00784-024-05798-w -
Journal of the Korean Association of... Jun 2024This study identifies factors for differential diagnosis among lesions by retrospectively comparing panoramic and cone-beam computed tomography images and analyzing the...
OBJECTIVES
This study identifies factors for differential diagnosis among lesions by retrospectively comparing panoramic and cone-beam computed tomography images and analyzing the characteristics of lesions associated with impacted mandibular third molars (IMTs).
MATERIALS AND METHODS
A retrospective cohort study was conducted in patients who simultaneously underwent IMT extraction surgery and related benign tumor resection or cyst enucleation at our institution from 2017 to 2021. To compare the characteristics of each group, two comparative analyses were conducted. The first comparison considered the most frequently observed lesions associated with IMTs: dentigerous cysts, odontogenic keratocysts (OKCs), and ameloblastoma. The second comparison involved placing dentigerous cysts, which have a relatively low recurrence rate, into group A and placing OKC, ameloblastoma, and odontogenic myxoma, which have high recurrence rates, into group B.
RESULTS
Significant differences in the size of the lesion were found in the order of ameloblastoma, OKC, and dentigerous cyst ( <0.05). The buccolingual width of ameloblastoma differed significantly from that of the other groups, with no significant difference observed between the OKCs and dentigerous cysts (=0.083).
CONCLUSION
Patient age and lesion size differed significantly among lesion types associated with IMTs, with younger age and larger lesions for OKCs and odontogenic tumors. OKCs are likely to have a larger mesiodistal width than dentigerous cysts. The buccolingual width of ameloblastomas was larger than those of dentigerous cysts and OKCs.
PubMed: 38940652
DOI: 10.5125/jkaoms.2024.50.3.153 -
Journal of the Korean Association of... Jun 2024The necessity of retrograde filling after apicoectomy is controversial in cases of non-inflammatory cysts as opposed to bacteria-related periapical abscesses. This study...
OBJECTIVES
The necessity of retrograde filling after apicoectomy is controversial in cases of non-inflammatory cysts as opposed to bacteria-related periapical abscesses. This study aims to investigate whether the presence or absence of retrograde filling during apicoectomy has differential long-term prognostic implications between inflammatory and non-inflammatory cysts.
MATERIALS AND METHODS
This retrospective study included patients who underwent tooth apicoectomy during jaw cyst enucleation between 2013 and 2022, and who underwent follow-up cone-beam computed tomography for at least 6 months. The prognosis of the tooth was evaluated during the follow-up period according to the cyst type, the presence or absence of retrograde filling, mandible or maxilla, and location.
RESULTS
A total of 147 teeth was included in this study. All the operated teeth underwent preoperative root canal treatment by an endodontic specialist. Apicoectomy was performed for 119 inflammatory cysts and 28 non-inflammatory cysts. Retrograde filling was performed on 22 teeth with inflammatory cysts and 3 teeth with non-inflammatory cysts. All teeth survived the 3.5-year follow-up (range, 1.0-9.1 years). However, 1 tooth with an inflammatory cyst developed complications 1 year after surgery that required re-endodontic treatment.
CONCLUSION
The prognosis of a tooth treated by apicoectomy without retrograde filling during cyst enucleation is favorable, regardless of the cyst type.
PubMed: 38940650
DOI: 10.5125/jkaoms.2024.50.3.140 -
Annals of Ibadan Postgraduate Medicine Apr 2024A number of challenges are being faced by children in orphanages, a major one being their oral health as a common unmet need. Studies have shown high prevalence of...
BACKGROUND
A number of challenges are being faced by children in orphanages, a major one being their oral health as a common unmet need. Studies have shown high prevalence of dental caries and oro-facial trauma. This has been attributed to overcrowding, lack of adequate staff, poor oral hygiene, improper dietary habits, inadequacies in the orphanage system, as well as inadequacies in the healthcare system.This study aimed at assessing the prevalence and factors affecting dental caries and trauma among children in orphanages in Ibadan.
MATERIALS AND METHOD
All the children within the age group (7 - 15 years) in all the 18 registered orphanages in the 5 Local Government Areas within Ibadan metropolis were recruited into the study. Intra-oral examination was done under natural light and caries detection was done using tactile and visual method. Sterile mouth mirrors and CPI probes were used for this purpose. Dental caries status and the predisposing factors in each child were assessed. Presence of dental trauma and the predisposing factors were also assessed. Data processing was carried out with the aid of SPSS version 21.
RESULTS
One hundred and forty-six children participated in the study, 51.4% of them were males while 48.6% were females. The age range and the mean age of the children were 7 - 15 years 9. 69 ± 3.78 respectively. The prevalence of dental caries among the children was 17.8% while that of dental trauma was 7.5%. The mean DMFT/dmft was found to be 0.42 ± 1.06. Gender and the presence of deep pits and fissures were the statistically significant predictors of dental caries.
CONCLUSION
Oral health is of utmost importance across all ages, much more pertinent among institutionalized children who are prone to dental caries and trauma as revealed by this study. An average child in an orphanage may be affected by both dental caries and trauma, but appears to be more prone to dental caries in this environment.
PubMed: 38939878
DOI: No ID Found