Mechanical properties of 3D-printed prosthetic materials compared with milled and conventional processing: A systematic review and meta-analysis of in vitro studies.

STATEMENT OF PROBLEM: Three-dimensional (3D) additive manufacturing (AM) is an evolving technology in dentistry, proposed as an alternative to subtractive milling manufacture (MM) or conventional processing. However, a systematic review of the use of AM technology instead of milling or conventional processing is lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the mechanical properties of 3D-printed prosthetic materials compared with MM and conventional techniques. MATERIAL AND METHODS: An electronic search of the literature was conducted on the MEDLINE (via PubMed), Scopus, and Web of Science databases. The inclusion criteria were in vitro studies published in the last 5 years, in English or Italian, and with 3D AM printed dental prosthetic materials. Data extraction was focused on dental prosthetic materials (ceramics, polymers, and metals) and their mechanical properties: flexural strength, fracture load, hardness, roughness, removable partial denture (RPD) fit accuracy, trueness, marginal discrepancy, and internal fit. Data considered homogenous were subjected to meta-analysis using the Stata17 statistical software program (95% confidence interval [CI]; α=.05). Since all variables were continuous, the Hedge g measure was calculated. A fixed-effects model was used for I2=0%, while the statistical analysis was conducted using a random-effects model with I2>0%. RESULTS: From a total of 3624 articles, 2855 studies were selected, and 76 studies included after full-text reading. The roughness of AM-printed ceramics generally increased compared with that of conventional processing while the marginal discrepancy was comparable both for ceramics and polymers. The flexural strength, hardness, and fracture load of AM-printed polymers were statistically lower than those of the conventional group (P<.05). No significant difference was detected in terms of hardness, roughness, marginal discrepancy, fracture load, trueness, or internal fit between the AM and MM techniques (P>.05). Milling techniques showed significantly higher values of flexural strength (Hedge g=-3.88; 95% CI, -7.20 to -0.58; P=.02), also after aging (Hedge g=-3.29; 95% CI, -6.41 to -0.17; P=.04), compared with AM printing. CONCLUSIONS: AM is comparable with MM in terms of mechanical properties, in particular with polymeric materials. The flexural strength of AM-printed prostheses is lower than with conventional and MM techniques, as are the parameters of hardness and fracture load, while the marginal discrepancy is similar to that of MM and conventional techniques. AM prostheses are commonly used for interim crowns and fixed partial dentures, as their rigidity and fracture resistance cannot support mastication forces for extended periods. More comparative studies are needed.

Heat-not-burn tobacco (IQOS), oral fibroblasts and keratinocytes: cytotoxicity, morphological analysis, apoptosis and cellular cycle. An in vitro study.

OBJECTIVES: The aim of this work is to investigate the biological effects of IQOS smoking on human gingival fibroblasts and human keratinocytes analysing cell viability, morphology, migration, apoptosis and cell cycle. BACKGROUND: Electronic cigarettes and tobacco heating systems have been marketed to reduce smoking damages caused by combustion. METHODS: Human gingival fibroblasts and human keratinocytes viability was determined by a colorimetric assay measuring mitochondrial dehydrogenase activity (MTT assay); after an in vitro exposure of 24 h, cell morphology was analysed with scanning electron microscope and cell migration was tested by Scratch assay, a method to mimic the migration of the cells during wound healing in vivo. Apoptosis and cell cycle were analysed with flow cytometry, and the expression of related genes (p53, Bcl2, p16 and p21) was indagated using real-time polymerase chain reaction. RESULTS: IQOS extracts increased both cell viability (23%-41% with fibroblasts and 30%-79% with keratinocytes) and migration. No morphological alterations were observed. IQOS extracts did not induced an increase in cell death, but rose the number of S- and G2/M-phase cells. IQOS extracts also significantly increased p53 expression by fibroblasts (undiluted and 6.25% dilution, 2- and 3.6-fold higher, respectively) and reduced both Bcl2 (about two- and fivefold, respectively) and p21 expressions (about twofold with both extracts), while on keratinocytes both undiluted and 6.25% dilution extracts increased Bcl2 expression (about four- and threefold higher, respectively) and reduced p53 expression (about two- and fivefold, respectively). CONCLUSION: IQOS smoke seemed to induce proliferation as highlighted by a viability assay, and migration and cell cycle analysis. The increased cell proliferation induced by IQOS devices must be carefully investigated for its possible clinical effects on oral cell populations.

Morpho-functional effects of different universal dental adhesives on human gingival fibroblasts: an in vitro study.

To analyze the effects of four universal adhesives (Optibond Solo Plus-OB, Universal Bond-UB, Prime&Bond Active-PBA, FuturaBond M + -FB) on human gingival fibroblasts in terms of cytotoxicity, morphology and function. After in vitro exposure for up to 48 h, fibroblast viability was determined by the MTT assay determined, morphology by phase-contrast microscopy and migration by the scratch wound assay. Expression levels of IL1ß, IL6, IL8, IL10, TNFα and VEGF genes were assessed by RT-PCR and their protein production by Western blot analysis. Apoptosis and cell cycle were analyzed by flow cytometry. OB and UB induced early morphological changes on fibroblasts (3 h) with extended cell death at 24 h/48 h. Gene expression of collagen type I and fibronectin increased fivefold compared with controls, elastin disappeared and elastase increased threefold, indicating gingival tissue tended to become fibrotic. Only UB and OB increased gene expression of inflammatory markers: IL1ß at 3 and 48 h (up to about three times), IL6 and IL8 at 3 h (up to almost four times) which corresponded to the increase of the activated form NF-kB. All adhesives showed an effect on the functionality of fibroblasts with cytotoxic effect time and concentration dependent. Among all the OB and UB adhesives, they showed the greatest cell damage. The in-depth analysis of the effects of universal adhesives and possible functional effects represents an important information for the clinician towards choosing the most suitable adhesive system.

Individual 3-dimensional printed mold for treating hard palate carcinoma with brachytherapy: A clinical report.

This clinical report describes the use of a 3-dimensional (3D) printer to create an individual mold for delivering high-dose-rate interventional radiotherapy for hard palate cancer. The maxillary teeth and palate were scanned with an intraoral scanner (3Shape TRIOS 3). The scan was transformed into a mesh using the standard tessellation language (STL) format and aligned with Digital Imaging and Communications in Medicine (DICOM) computed tomography (CT) images using free Blue Sky Plan 4 planning software. A mold was generated by tracing a guideline around the gingival margins of the maxillary teeth and palate on the scan mesh in accordance with established parameters. All data were imported into computer-aided design (CAD) software. For this patient, 3 parallel 2.2-mm-diameter ducts were placed 10 mm from each other in the mold mesh. A CT scan of the patient's mouth with the mold in place was used for treatment planning. Treatment was delivered by means of microSelectron digital afterloading.

In Vitro effects of alternative smoking devices on oral cells: Electronic cigarette and heated tobacco product versus tobacco smoke.

OBJECTIVE: To investigate the biological effects of electronic cigarette (e-cigarette) and heated tobacco product extracts respect to tobacco smoke extract on human gingival fibroblasts and human oral keratinocytes analysing cell viability, morphology, migration, apoptosis, cell cycle and epithelial-mesenchymal transition (EMT). DESIGN: Human gingival fibroblasts and human oral keratinocytes viability was analysed by MTT assay, cell morphology using scanning electron microscope (SEM) and cell migration by Scratch assay, a method that mimics the cell migration during wound healing in vivo. Apoptosis and cell cycle were analysed with flow cytometry and the related-gene expression of TP53, BCL2, CDKN2A and CDKN1A was indagated using real-time polymerase chain reaction. EMT process was analysed through expression of specific markers: CDH1, SNAI2, TWIST1, MMP2, FN1 and VIM. All investigations were evaluated after 24 h an in vitro exposure. RESULTS: Undiluted tobacco smoke extract induced significant inhibition of cell viability and cell migration, caused morphological alterations and induced an increase in cell death. No alterations or damage were observed after treatment with e-cigarette extracts. Heated tobacco product extract induced proliferation as highlighted by an increase of cell viability, cell migration and alterations of cycle analysis. CONCLUSIONS: Comparing the different cigarette extracts, tobacco smoke turns out to be the most harmful, e-cigarette did not determine morphological and functional alterations and heated tobacco product must be carefully investigated for its possible clinical effects on oral cell populations.

Use of the Er:YAG Laser in Conservative Dentistry: Evaluation of the Microbial Population in Carious Lesions.

The aim of this study is to investigate the Erbium:Yttrio-Aluminum-Granate (Er:YAG) laser photothermal and mechanical effects on cariogenic species concentration and on the microbial load composition of therapeutic cavities, in order to evaluate the possible micro-organisms reduction and make a comparison with manual and rotating conventional therapy (CT). A clinical trial was designed, including adults with active deep carious lesions on permanent teeth who were divided into two groups, i.e., control group and intervention group treated with CT and Er:YAG therapy, respectively. Before and after any conservative treatment, two oral samples were collected using a small sterile microbrush scrubbed within the base of the dentinal cavity tissue. The percentage of reduction and the colony-forming units (CFUs) count after Er:YAG and conventional treatments were compared for total microorganisms, including Candida spp., Streptococcus spp., and Lactobacillus spp. The microbial reduction varied from 90.2% to 100% and was significantly observed for total microorganisms and Streptococcus spp. (p < 0.05). The Er:YAG laser shows the potential for clinical applications, especially with paediatric and complicated patients, thanks to its minimally invasive properties and its effect on the reduction of microbial load.

Systematic Review of the Literature on Dental Caries and Periodontal Disease in Socio-Economically Disadvantaged Individuals.

Dental caries and periodontal disease represent a health problem and a social cost for the entire population, and in particular for socio-economically disadvantaged individuals who are less resistant to disease. The aim of this review is to estimate the prevalence and severity of the two dental pathologies, caries and periodontal disease, in the different classes of socio-economically disadvantaged subjects and to understand which of them are most affected. A systematic search of the literature was performed in MEDLINE (via PubMed), EMBASE and Web of Science after establishing a suitable search strategy for each database, using keywords related to socio-economically vulnerable classes and health outcomes. Socio-economically disadvantaged individuals are more susceptible to tooth decay and periodontal disease (with relative tooth loss) than non-vulnerable people. Additionally, when multiple vulnerabilities are combined in the same subject, these oral diseases worsen. There is no type of vulnerability more affected by caries and periodontitis than others, since overall they all have severe disease indices. The data from this systematic literature review might be useful for health policy makers looking to allocate more resources and services to socially disadvantaged individuals, resulting in making them more resilient to oral disease due to their social marginalization.

Bio-mechanical characterization of a CAD/CAM PMMA resin for digital removable prostheses.

OBJECTIVE: To compare the mechanical and biological features of a polymethylmethacrylate (PMMA) disc for CAD/CAM prostheses (test samples, TG) with a traditional resin (control samples, CG). METHODS: Mechanical analysis was performed using Dynamic Mechanical Analysis (DMA) and Brillouin's micro-spectroscopy. Human keratinocyte morphology and adhesion were analyzed by scanning electronic microscopy (SEM), cytotoxicity by the MTT assay, apoptosis by flow cytometry and p53, p21 and bcl2 gene expression by real time PCR. RESULTS: TG exhibited a higher elastic modulus than CG (range 5100-5500 ± 114.3 MPa vs 3000-3300 ± 99.97 MPa). The Brillouin frequency was found at ωB= (15.50 ± 0.05) GHz for TG and at ωB_1 = (15.50 ± 0.05) GHz and ωB_2 = (15.0 ± 0.1) GHz for CG where two peaks were always present independently of the sample point. SEM analysis revealed that keratinocytes on TG disks appeared to be flattened with lamellipodia. Keratinocytes on CG disks rose above the substrate with cytoplasmatic filaments. MTT viability data at 3 h and 24 h showed TG was significantly less cytotoxic than CG (p < 0.001). No significant differences emerged in apoptosis on CG and TG. Real-time PCR showed p53 expression increased after 3 h by about 9-fold in keratinocytes on TG (p < 0.001) and about 5-fold in those on CG (p < 0.001). High p53 expression persisted after 24 h on both disks. No significant variations were observed in p21 and bcl2 expression at any time-point. SIGNIFICANCE: PMMA resins, as used in CAD/CAM technology, displayed suitable biocompatible and mechanical properties for removable prostheses.

Hydrogen sulphide induces micro opioid receptor-dependent analgesia in a rodent model of visceral pain.

BACKGROUND: Hydrogen sulphide (H2S) is a gaseous neuro-mediator that exerts analgesic effects in rodent models of visceral pain by activating KATP channels. A body of evidence support the notion that KATP channels interact with endogenous opioids. Whether H2S-induced analgesia involves opioid receptors is unknown. METHODS: The perception of painful sensation induced by colorectal distension (CRD) in conscious rats was measured by assessing the abdominal withdrawal reflex. The contribution of opioid receptors to H2S-induced analgesia was investigated by administering rats with selective mu, kappa and delta opioid receptor antagonists and antisenses. To investigate whether H2S causes mu opioid receptor (MOR) transactivation, the neuronal like cells SKNMCs were challenged with H2S in the presence of MOR agonist (DAMGO) or antagonist (CTAP). MOR activation and phosphorylation, its association to beta arrestin and internalization were measured. RESULTS: H2S exerted a potent analgesic effects on CRD-induced pain. H2S-induced analgesia required the activation of the opioid system. By pharmacological and molecular analyses, a robust inhibition of H2S-induced analgesia was observed in response to central administration of CTAP and MOR antisense, while kappa and delta receptors were less involved. H2S caused MOR transactivation and internalization in SKNMCs by a mechanism that required AKT phosphorylation. MOR transactivation was inhibited by LY294002, a PI3K inhibitor, and glibenclamide, a KATP channels blocker. CONCLUSIONS: This study provides pharmacological and molecular evidence that antinociception exerted by H2S in a rodent model of visceral pain is modulated by the transactivation of MOR. This observation provides support for development of new pharmacological approaches to visceral pain.

Model for Taking Care of Patients with Early Childhood Caries during the SARS-Cov-2 Pandemic.

Pending the availability of vaccines to contain the SARS-CoV-2 pandemic, the current solution is "social distancing" with a reduction of dental treatments to those assessed as urgent and emergency cases. These treatments also involve Early Childhood Caries (ECC) due to the fact that this disease affects preschool children (a vulnerable population) and, in addition, shows a propensity to evolve into more serious complications (dental pain, infections). A narrative review was carried out to support a protocol for treating ECC with efficacious and safe (in terms of SARS-CoV-2 transmission) procedures. Protocol involves criteria for patients' selection remotely (telemedicine), and well-detailed criteria/equipment and hygiene procedures to combat against SARS-CoV-2 transmission. Moreover, the protocol proposes innovative caries treatments, named Minimally Invasive Treatments (MITs), well known in pedodontics for their high level of children's acceptance during dental care. MITs allow for caries removal (particularly in primary teeth) without any high-speed rotating instrument cooled with nebulized air-water spray (with high risk of virus environmental diffusion), usually adopted during traditional treatments. For evaluating MITs effectiveness in caries management, only Systematic Review and Randomized Controlled Trials (RCTs) were included in our study, without any risk of bias assessment. The indications proposed in this protocol could support clinicians for the temporary management of ECC until the SARS-CoV-2 pandemic ends.

Lasers to prevent dental caries: a systematic review.

OBJECTIVE: To assess the effectiveness of lasers (at sub-ablative parameters) in reducing caries incidence compared with traditional prophylactic interventions (TPIs) when used alone or together with other TPIs such as pits and fissures sealant or fluoride gels or varnishes. DESIGN: A systematic review. Data sources include Medline (via PubMed), Embase, Web of Science and the Cochrane Library (December 2019). ELIGIBILITY CRITERIA: Only randomised trials (RCTs) and controlled clinical trials (CCTs) dealing with prophylactic lasers use (vs TPI or untreated teeth) were considered as eligible. We excluded in vitro and ex vivo studies. DATA EXTRACTION: Eligible studies were selected and data extracted independently by two reviewers. Risk of bias was assessed adopting the Cochrane Risk of Bias tool. Data on caries incidence, sealant retention, fluoride uptake, adverse events, treatment duration, patients' discomfort and cost-effectiveness ratio was extracted. DATA ANALYSIS: Extracted data were presented narratively due to the heterogeneity of included studies. RESULTS: Seven RCTs and two CCTs, all with an evident risk of bias, met inclusion criteria, pooling together 269 individuals and 1628 teeth. CO2, neodymium-doped yttrium aluminium garnet, erbium-doped yttrium aluminum garnet (Er:YAG), erbium, chromium: yttrium scandium gallium garnet (Er,Cr:YSGG) and Argon lasers were used. In the permanent dentition, lasers only when used in combination with TPIs were effective in reducing caries when compared with untreated teeth (risk ratio (RR)=0.44 (0.20-0.97); Er:YAG laser) or with TPIs used alone (RR=0.39 (0.22-0.71); CO2 laser). Moreover, Argon laser significantly improved the fluoride uptake into the enamel surfaces (ANalysis Of VAriance (ANOVA) tests: 95%, p<0.0001). Likewise, sealant retention improved when acid etching was performed on previously irradiated enamel fissures by CO2 laser (RR=0.63 (0.38-1.04)) or Er:YAG laser (RR=0.54 (95% CI: 0.34 to 0.87)). In addition, laser resulted safe and well tolerated by patients. CONCLUSION: Despite some positive indications, an inadequate level of evidence was found in the included studies concerning the lasers' effectiveness in preventing caries. Further studies with a higher methodological quality level are required.

Oral Health Knowledge Level of Nursing Staff Working in Semi-Intensive Heart Failure Units.

PURPOSE: Critical care units, such as heart failure units, house inpatients with a compromised general health status that requires rigorous prevention of further complications. Oral health infections that gain access through the bloodstream or airway might represent such potential complications (eg, endocarditis pneumonia). Avoiding these critical occurrences requires that adequate oral health care be provided by nursing personnel. Here we assessed the knowledge of oral health care practices by nurses working in three Italian heart failure units in Umbria, Italy. DESIGN: This was a cross-sectional study. METHODS: Forty-four nurses were interviewed using a six-item modified Adams' questionnaire on the topic of oral health care. A multidisciplinary panel of experts established the criteria for answer correctness based on the most relevant dentistry literature evidence and judged each reply. The expected percentage of correctly replying nurses was 75%, and significant differences from this expected probability were calculated with one-sided binomial probability tests. Cronbach's α method was used to establish the questionnaire's internal consistency (reliability). RESULTS: For five out of six questionnaire items, the percentage of nurses who correctly answered was significantly lower than the expected value of probability. Lack of knowledge was found for usefulness of checking the patients' mouths (p=0.003), the most relevant lesions affecting the mouth (p=0.0001), the tools/solutions for cleaning the mouth and dentures (p= 0.0416), and drugs that affect the mouth and their side effects (p<0.0001). CONCLUSION: In this study, few nurses working in heart failure units showed both an adequate willingness to check inpatients and a good knowledge of oral health care (significantly lower than the expected 75%). Further studies that use validated questionnaires and include more participants should be conducted to confirm and elaborate on our preliminary data.

Biological effects of Cannabidiol on normal human healthy cell populations: Systematic review of the literature.

A systematic review was performed to evaluate the biological effects of Cannabidiol (CBD), one of the major components of Cannabis Sativa, on normal human healthy cell populations in terms of cell viability, proliferation, migration, apoptosis and inflammation. Inclusion criteria were: studies on cell lines and primary cell culture from healthy donors, CBD exposure as variable, no CBD exposure as control and published in English language. Quality assessment was based on ToxR tool, with a score of reliability ranging from 15 to 18.Following the PRISMA statement, three independent reviewers performed both a manual and an electronic search using MEDLINE via PubMed, Scopus, Web of Science and Cochrane. From a total of 9437eligible articles, 29 studies have been selected. The average quality assessment score was 16.48.Theresults showed heterogeneous CBD concentration exposure (0.01-50 µM or 0.1 nmol/mL-15 mg/mL). The definition of a threshold limit would allow the identification of specific effects on expected outcomes. From the data obtained CBD resulted to inhibit cell viability in a dose-dependent manner above 2 µM, while in oral cell populations the inhibitory concentration is higher than 10 µM. Moreover, it was observed a significantly inhibition of cell migration and proliferation. On the contrary, it was highlighted a stimulation of apoptosis only at high doses (from 10 µM).Finally, CBD produced an anti-inflammatory effect, with a reduction of the pro-inflammatory cytokine gene expression and secretion. CBD down-regulated ROS production, although at high concentrations (16 µM) increased ROS-related genes expression. The diffusion of CBD for therapeutic and recreational uses require a precise definition of its potential biological effects. A thorough knowledge of these aspects would allow a safe use of this substance without any possible side effects.

Evaluation of the Accuracy of Four Digital Methods by Linear and Volumetric Analysis of Dental Impressions.

The quality of dental arch impression has a substantial role in the precision of the intervention. It is traditionally acquired with resins that solidify when in contact with the air. Compared to that method, digital impression gives great advantages and, together with three-dimensional (3D) digitization devices, allows a simplification of the digital impression process. The growing adoption of such systems by a large number of dental clinics determines the need for an in-depth evaluation of the accuracy and the precision of the different systems. The aim of this work is to define a methodology for the evaluation of the accuracy and precision of 3D intraoral and desktop scanning systems, by using volumetric and linear methods. The replica of a tooth was realized with zirconium; afterward, high-accuracy point clouds of the master model were acquired by a coordinate measurement machine (CMM). In this way, the dimensions of the replica were accurately known. An intraoral scanner (I) and three desktops (D1, D2, D3) were then used to scan the replica. The geometry resulting from the CMM was compared with the ones derived from the scanners, using two different commercial programs (Geomagic and 3-Matic) and a custom-developed algorithm (MATLAB). Geomagic showed the mean values to be in a range from 0.0286 mm (D1) to 0.1654 mm (I), while 3-Matic showed mean values from -0.0396 mm (D1) to 0.1303 mm (I). MATLAB results ranged from 0.00014 mm (D1) to 0.00049 mm (D2). The probability distributions of the volumetric error of the measurements obtained with the different scanners allow a direct comparison of their performances. For the results given by our study, the volumetric approach that we adopted appears to be an excellent system of analysis.

Biological, thermal and mechanical characterization of modified glass ionomer cements: The role of nanohydroxyapatite, ciprofloxacin and zinc l-carnosine.

The study evaluated the effects of 4 wt% nanohydroxyapatite (HA), 6 wt% zinc l-carnosine (MDA) and 1.5 wt% Ciprofloxacin (AB) on the mechanical, thermal and biological properties of glass ionomer cements (GIC). Filler and additive concentrations were selected after a previous study had tested single components and different percentages. Specimens included five silicon molds of each GIC cement for all tests. They were stored at room temperature for 24 h from specimen collection to analysis. Mechanical tests, calorimetric analysis, morphological investigation, antibacterial and cell viability assays were conducted. One-way analysis of variance (ANOVA) was used for data analysis with significance set at p < 0.05. Adding HA, MDA and AB to GICs modified their thermal, mechanical and microbiological properties. Polymerization increased. A slight decrease in the compressive strength of modified GICs was observed in dry condition (p < 0.05). Cement extracts affected cell viability in relation to extract dilution. Mechanical behavior improved in modified glass ionomer cements, especially with the powder formulated antibiotic. Overall cytotoxicity was reduced. Therefore adding nanohydroxyapatite, antibiotic and a mucosal defensive agent to conventional glass ionomer cement in special need patients could improve the clinical, preventive and therapeutic performance of the cements, without altering their mechanical properties.

Cytotoxicity of universal dental adhesive systems: Assessment in vitro assays on human gingival fibroblasts.

Universal adhesives are the most important innovation in restorative dentistry. They are composed of different monomers, solvents and fillers. The potential cytotoxic effect of these materials is an important scientific aspect in recent literature. The aim of this study was to determine, using different in vitro techniques, the cytotoxicity evaluation of seven universal enamel-dental adhesives on human gingival fibroblasts. For this purpose, seven universal dental enamel adhesives have been evaluated by in vitro cytotoxicity tests using direct contact tests (an unpolymerized and a polymerized method) and an indirect contact test: preparation of extracts. The polymerized method showed a cytotoxicity range from 36% (G-PremioBond, GPB) to 79% (FuturaBond M+, FB). With the unpolymerized direct methods the range was from 4% (Prime&Bond Active, PBA) to 40% (Ibond Universal, IB) for undiluted adhesives; generally passing to the major dilutions the test showed a strong inhibitory activity by all the adhesives. Whereas with the indirect method by diluting the extracts of all dental adhesives the cell viability increased. The data obtained from the work has shown a lower cytotoxic effect of Optibond Solo Plus (OB) and Adhesive Universal (AU) with more reliable results with the extracts technique. The choice of reliable in vitro cytotoxic technique could represent, in dental practice, an important aid for clinical procedures in the use of adhesive systems.

Sonic and ultrasonic oscillating devices for the management of pain and dental fear in children or adolescents that require caries removal: a systematic review.

OBJECTIVES: To evaluate the effectiveness and degree of acceptance by children and adolescents of the use of oscillating tips compared with rotating drills. DESIGN: Systematic review. DATA SOURCES: PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Library and Web of Science (October 2017). ELIGIBILITY CRITERIA: Controlled randomised or non-randomised trials that evaluated sonic and ultrasonic oscillating devices versus rotating drill. DATA EXTRACTION: Eligible studies were selected and data extracted independently by two reviewers. Risk of bias was assessed using the Cochrane Method. RESULTS: Two controlled clinical trials comprising 123 children aged 2-12 years old were identified. Both trials were at high risk of selection bias and unclear risk of detection bias. In one trial, pain due to the use of oscillating drill resulted lower than employing rotating drill (Verbal Hochman Scale: RR 0.64 (95% CI 0.41 to 1.00); Visual Facial Expression Scale: RR 0.64 (95% CI 0.44 to 0.94)). In another study, compared with traditional drill ultrasonic tip was associated with a lower level of patient's discomfort (RR 0.40 (95% CI 0.20 to 0.79)) but not with dental anxiety (RR 1.29 (95% CI 0.97 to 1.71)). The effectiveness of the removal of caries as well as fillings durability were only considered in one study, but no statistically significant differences were found between the two interventions. CONCLUSIONS: The evidence based on two low-quality studies was insufficient to conclude that the use of oscillating tips for the management of pain and dental fear in children or adolescents compared with rotating drills was more effective.

Evidence of pharmacological and non-pharmacological interventions for the management of dental fear in paediatric dentistry: a systematic review protocol.

INTRODUCTION: Several techniques have been proposed to manage dental fear/dental anxiety (DFA) in children and adolescents undergoing dental procedures. To our knowledge, no widely available compendium of therapies to manage DFA exists. We propose a study protocol to assess the evidence regarding pharmacological and non-pharmacological interventions to relieve dental anxiety in children and adolescents. METHODS AND ANALYSIS: In our systematic review, we will include randomised trials, controlled clinical rials and systematic reviews (SRs) of trials that investigated the effects of pharmacological and non-pharmacological interventions to decrease dental anxiety in children and adolescents. We will search the Cochrane Database of Systematic Reviews, the Cochrane Database of Abstracts of Reviews of Effects=, the Cochrane Central Register of Controlled Trials, PubMed, PsycINFO, Cumulative Index to Nursing and Allied Health Literature and the Web of Science for relevant studies. Pairs of review authors will independently review titles, abstracts and full texts identified by the specific literature search and extract data using a standardised data extraction form. For each study, information will be extracted on the study report (eg, author, year of publication), the study design (eg, the methodology and, for SRs, the types and number of studies included), the population characteristics, the intervention(s), the outcome measures and the results. The quality of SRs will be assessed using the A Measurement Tool to Assess Reviews instrument, while the quality of the retrieved trials will be evaluated using the Cochrane Handbook for Systematic Reviews of Interventions criteria. ETHICS AND DISSEMINATION: Approval from an ethics committee is not required, as no participants will be included. Results will be disseminated through a peer-reviewed publications and conference presentations.

Effect of fibre posts, bone losses and fibre content on the biomechanical behaviour of endodontically treated teeth: 3D-finite element analysis.

The aim of this work was to evaluate the stress distribution inside endodontically treated teeth restored with different posts (glass fibre, carbon fibre and steel posts) under different loading conditions by using a 3D-finite element analysis. The effect of masticatory and impact forces on teeth with different degrees of bone loss was analysed. The model consists of: dentine, post, cement, gutta-percha, core and crown. Four simulations were conducted with two static forces (170N horizontal and 100N oblique) and two sections constrained: 1mm (alveolar bone position in a normal periodontium) and 6mm (middle of root) below the crown. Von Mises and the principal stresses were evaluated and analysed with a 3-way ANOVA and Tukey test (α=0.05) and the effect of fibre percentage analysed. Significant differences were found among the stress values for all conditions (p<0.05). Impact load was always responsible for the most critical situation especially when the bone loss was more evident. The system with steel posts showed the highest principal stresses at the post-cement interface with horizontal load and top constraints (compressive stress of 121MPa and tensile stress of 115MPa). The use of glass posts provides a more homogeneous behaviour of the system with lower stresses. Higher fibre percentages gave higher stress in the posts. Moreover, larger bone losses are responsible for important increase in stress. Thus, this work demonstrated that periodontal disease has an important role in the success of tooth restoration after endodontic therapy, influencing the choice of post material and depth.

Association between periodontal disease and left ventricle mass in essential hypertension.

Chronic periodontitis has been associated with an increased risk for cardiovascular disease. Left ventricular mass is an established independent predictor of cardiovascular disease. In the present cross-sectional study, we tested the association between periodontitis and left ventricular mass in subjects with essential hypertension. One hundred four untreated subjects with essential hypertension underwent clinical examinations, including echocardiographic study, laboratory tests, and assessment of periodontal status according to the community periodontal index of treatment needs (CPITN). With increasing severity of periodontitis, there was a progressive increase in left ventricle mass. Mean values (g/height2.7) were 39.0 (+/-2.7) in CPITN 0 (periodontal health), 40.2 (+/-6.4) in CPITN 1 (gingival bleeding), 42.7 (+/-6.8) in CPITN 2 (calculus), 51.4 (+/-11.7) in CPITN 3 (pockets 4 to 5 mm), and 76.7 (+/-11.3) in CPITN 4 (pockets > or =6 mm) (overall F 51.2; P<0.0001). Body surface area (P=0.04), systolic (P<0.0001) and diastolic (P<0.01) blood pressure, and left ventricular mass (P<0.0001) were determinants of a composite of CPITN 3 and 4. In a multivariate logistic analysis, left ventricular mass was the sole determinant (P<0.0001) of CPITN stages 3 and 4. Our findings suggest a direct association between severity of periodontitis and left ventricular mass in subjects with essential hypertension. Periodontal evaluation might contribute to refine cardiovascular risk assessment in hypertensive subjects.