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BACKGROUND: One of the main factors for the osseointegration of dental implants is the development of an adequate soft tissue barrier, mainly composed by collagen, which protects the implant from bacterial development. The structural features of the peri-implant collagen are influenced by the implant components and, in particular, by the type of the surface. In the clinical practice, healing abutments are characterized by smooth surfaces, named machined. Recently, a new laser technique, Synthegra, has been developed to obtain a topography-controlled surface with micrometric regular pores that seems reducing the risk of peri-implantitis. Based on this background, this study aims investigating the structural organization and spatial distribution of collagen surrounding healing abutments characterized by laser-treated and machined surfaces. METHODS: Gingiva portions surrounding custom-made healing abutments (HA), characterized by alternated laser-treated and machined surfaces, were collected and analyzed by combining Fourier Transform InfraRed Imaging (FTIRI) spectroscopy, a non-invasive and high-resolution bidimensional analytical technique, with histological and multivariate analyses. RESULTS: Masson's trichrome staining, specific for collagen, highlighted a massive presence of collagen in all the analyzed samples, evidencing a surface-related spatial distribution. The nature of collagen, investigated by the FTIRI spectroscopy, appeared more abundant close to the laser-treated surface, with a perpendicular disposition of the bundles respect to the HA; conversely, a parallel distribution was observed around the machined surface. A different secondary structure was also found, with a higher amount of triple helices and a lower quantity of random coils in collagen close to the laser treated surfaces. CONCLUSIONS: FTIRI spectroscopy demonstrates that the use of a laser treated transmucosal surface can improve the morphological organization of the peri-implant collagen, which presents a distribution more similar to that of natural teeth. TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov Identifier: (Registration Number: NCT05754970). Registered 06/03/2023, retrospectively registered, https://clinicaltrials.gov/show/NCT05754970 .
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Implantes Dentários , Colágeno , Gengiva/patologia , Lasers , Osseointegração , Propriedades de Superfície , HumanosRESUMO
BACKGROUND: Today dental implants represent an effective therapy in case of partial or total edentulism, with an excellent success rate. Despite the results obtained, there may be biological or mechanical complications during the therapy, which lead to the loss of the implant. This systematic review aims to evaluate the current state of the art in the literature on techniques used for the removal of dental implants. Various aspects will be analyzed, such as the success of the technique, any complications, and the advantages and disadvantages of their use. METHODS: Two reviewers conducted a literature analysis (PubMed, Embase, Web of Science) of the last 20 years (2003-2023). The main criterion analyzed was the success of the technique, while secondary outcomes such as complications and risks of the technique were also analyzed. 258 articles were identified in the various search databases. 42 eligible articles were subsequently identified after an article screening. Only 18 full texts were subsequently included in the review. RESULTS: A total of 18 articles were selected and 1142 implants and 595 patients were included. The main techniques used were the Counter-Torque Ratchet Technique (CTRT), Piezoelectric bone surgery (PBS), trephine drills, carbide burs, Erbium, Chromium, Yttrium, Scandium, Gallium, Garnett (Er:Cr:YSGG) laser and carbon dioxide (CO2) laser. Combined uses of techniques have been identified such as: PBS and trephine burs or carbide burs, trephine burs with the use of a 3d-printed guide, CTRT and trephine burs. The technique with the highest success rate, less morbidity for the patient, and less removal of bone appears to be the CTRT. CONCLUSIONS: The use of conservative techniques, especially CTRT, in bone removal is useful to allow for immediate implant placement in the removal area. However, further studies with a high sample size are needed to be performed on all techniques, particularly new randomized controlled trials (RCTs) that allow for the analysis of the success of alternative techniques such as Laser and Piezosurgery, which appear to be very promising.
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Prótese Ancorada no Osso , Implantes Dentários , Lasers de Estado Sólido , Humanos , Implantação Dentária Endóssea/métodos , ÍtrioRESUMO
BACKGROUND: Dental implant is the principal treatment for edentulism and the healthiness of the peri-implant tissue has a pivotal role for its longterm success. In addition, it has been shown that also the topography of the healing abutment can influence the outcome of the restoration. The objective of this human clinical trial was to assess the impact of a novel laser-treated healing abutment on peri-implant connective tissue and extracellular matrix proteins compared to the conventional machined surface, which served as the control group. METHODS: During second surgical stage a customized healing abutment were inserted on 30 single dental implants. Healing abutments were realized with two alternated different surface (two side laser-treated surfaces and two side machined surfaces) in order to be considered both as test and control on the same implant and reduce positioning bias. Following the soft tissue healing period (30 ± 7 days) a 5 mm circular biopsy was retrieved. Immuno-histochemical and quantitative real-time PCR (qPCR) analyses were performed on Collagen, Tenascin C, Fibrillin I, Metalloproteinases (MMPs) and their inhibitor (TIMPs). 15 were processed for qPCR, while the other 15 were processed for immunohistochemical analysis. Paired t-test between the two groups were performed. A value of p < 0.05 was considered statistically significant. RESULTS: Results revealed that the connective tissue facing the laser-treated surface expressed statistically significant lower amount of MMPs (p < 0.05) and higher level of TIMPs 3 (p < 0.05), compared to the tissue surrounding the machined implant, which, in turn expressed also altered level of extracellular matrix protein (Tenascin C, Fibrillin I (p < 0.05)) and Collagen V, that are known to be altered also in peri-implantitis. CONCLUSIONS: In conclusion, the laser-treated surface holds promise in positively influencing wound healing of peri-implant connective tissue. Results demonstrated that topographic nature of the healing abutments can positively influence mucosal wound healing and molecular expression. Previous studies have been demonstrated how laser treatment can rightly influence integrity and functionality of the gingiva epithelium and cell adhesion. Regarding connective tissue different molecular expression demonstrated a different inflammatory pattern between laser treated or machined surfaces where laser treated showed better response. Targeted interventions and preventive measures on peri- implant topography could effectively minimize the risk of peri-implant diseases contributing to the long-term success and durability of restoration. However, new studies are mandatory to better understand this phenomenon and the role of this surface in the peri-implantitis process. TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov Identifier: (Registration Number: NCT05754970 ). Registered 06/03/2023, retrospectively registered.
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Implantes Dentários , Peri-Implantite , Humanos , Implantes Dentários/efeitos adversos , Tenascina , Colágeno , Tecido Conjuntivo , Lasers , Fibrilinas , Metaloproteinases da Matriz , TitânioRESUMO
Background: Squamous cell carcinoma is the most frequent malignant cancer of the oral cavity. Metastasis involvement is one of the most relevant prognostic factors in terms of survival probability. Patients with oral cancers often undergo extensive en bloc resective surgery of the mandible and maxilla, with or without cervical nodal dissection, based on the presence or occult risk of regional metastases. Several factors affect the choice of flap, to recover aesthetics and function. Case Presentation: The case of a 60-year-old man who underwent maxillectomy with neck dissection as well as a reconstruction with a combination of multiple vascularized free flaps is presented. Conclusions: The excellent integration of the free flaps and the total absence of complications led to a high-quality aesthetic and functional performance of the reconstruction obtained through two different flaps. More specifically, the fibular free flap for bone reconstruction allows a two-team approach and maintains an excellent vascularization, even in case of several osteotomies for the maxillary reconstruction as reported. In addition, the use of free radial forearm flap for soft tissue reconstruction permits to obtain long caliber vessels, thus facilitating surgery without repositioning of the patient during surgery and therefore, consequently reducing surgery times.
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Carcinoma de Células Escamosas , Retalhos de Tecido Biológico , Neoplasias Bucais , Procedimentos de Cirurgia Plástica , Carcinoma de Células Escamosas/cirurgia , Humanos , Masculino , Mandíbula/cirurgia , Pessoa de Meia-Idade , Neoplasias Bucais/cirurgiaRESUMO
The health of peri-implant soft tissues is important for the long-term success rate of dental implants and the surface topography is pivotal in influencing it. Thus, the aim of this study was to evaluate, in human patients, the inflammatory mucosal microenvironment in the tissue surrounding a new, nanoscale, laser-treated healing abutment characterized by engineered nanopores versus a standard machined-surface. Analyses of anti- and pro-inflammatory markers, cytokeratins, desmosomal proteins and scanning electron microscopy were performed in 30 soft-tissue biopsies retrieved during second-stage surgery. The results demonstrate that the soft tissue surrounding the laser-treated surface was characterized by a lower grade of inflammation than the one facing the machined-surface, which, in turn, showed a disrupted epithelium and altered desmosomes. Moreover, higher adhesion of the epithelial cells on the laser-treated surface was detected compared to the machined one. In conclusion, the laser-treated surface topography seems to play an important role not only in cell adhesion, but also on the inflammatory makers' expression of the soft tissue microenvironment. Thus, from a clinical point of view, the use of this kind of topography may be of crucial importance not only on healing abutments but also on prosthetic ones.
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Dente Suporte , Implantes Dentários , Gengiva/fisiologia , Idoso , Adesão Celular , Feminino , Gengiva/citologia , Gengivite/etiologia , Gengivite/metabolismo , Humanos , Molécula 1 de Adesão Intercelular/metabolismo , Queratinas , Terapia a Laser/métodos , Masculino , Metaloproteinase 9 da Matriz/genética , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Nanoporos , Inibidor Tecidual de Metaloproteinase-1/genética , Fator de Necrose Tumoral alfa/genéticaRESUMO
Objective: To investigate the therapeutic and prophylactic use of antibiotics in dentistry in two countries. Methods: This study used questionnaires to examine the prescribing habits of dentists in Italy (9th country in Europe for systemic antibiotic administration) and Albania an Extra European Union Country. A total of 1300 questionnaires were sent to Italian and Albanian dentists. Results: In total, 180 Italian and 180 Albanian dentists completed the questionnaire. Penicillin use was higher in Italy (96.6 %) than Albania (82.8 %). Only 26.1 % of Italian dentists and 32 % of Albanian dentists followed the national guidelines for antibiotic administration. Conclusions: Dentists tend to overprescribe antibiotics for treating existing conditions or as prophylaxis. They also highlighted a lack of adherence to established guidelines for antibiotic use. In addition, factors such as age, nationality, and sex appeared to influence the choice of antibiotics. Clinical significance: Recently, the growth of antibiotic-resistant bacteria has become a global concern. The authors of this article highlight how dentists often prescribe antibiotics without a real need. Limiting the use of antibiotics in this category may help mitigate antibiotic resistance.
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Clinical outcomes of dental restorations depend primarily on the choice of materials used, and nowadays, dental CAD-CAM (Computer-Aided Design Computer-Aided Manufacturing) materials have strongly changed daily clinical practice. The aim of this systematic review is to analyze CAD-CAM dental materials according to their mechanical properties and in relation to their clinical applications. A literature review was performed on PubMed, Scopus, Web of Knowledge, and the Cochrane Library. Articles addressing at least one of the following topics regarding dental materials for CAD-CAM systems: manufacturers, mechanical features, materials' composition, optical properties, clinical indications, and/or outcomes were included in the review. A flowchart was performed as described in the PRISMA guidelines. Among the 564 articles found, 63 were analyzed and evaluated. Within the limitations of this systematic review, it can be concluded that CAD-CAM materials present a wide range of clinical applications due to their improved mechanical properties. Specifically, in addition to materials that have been in use for a long time (such as feldspathic ceramics), resin block composites can also be used for permanent restorations.
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Guided implant surgery can enhance implant placement positioning, increasing predictability and decreasing postoperative complications., To date, the best protocol to be used for template realization is still unknown. Thus, the aim herein was to clinically compare the accuracy of two different protocols. A total of 48 implants were divided into Group A (24 implants), in which a stereolithographic template was realized using the digital imaging and communications in medicine (DICOM) data arrived from cone beam computer tomographies (CBCTs) (patients and prothesis alone), and Group B (24 implant), in which a standard intraoral stent with a standardized extraoral support was used for patients' intraoral impressions and CBCT. The preimplant virtual planning and postsurgery CBCT images of both groups were superimposed, and differences were registered in terms of average deviations at the platform (a) and implant apex (b), mean depth change (c), and angular deviation (d). The results demonstrated that there were no statistically significant differences between groups (p = 0.76) for the parameters measured. However, statistically significant differences (p < 0.05) were found between maxillary and mandible implant surgery, as the latter showed greater accuracy. Additional studies are necessary to further reduce discrepancies between planning and surgical procedures.
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The literature highlights differences in the dental conditions of people with disabilities compared with the general population. The aim of this study was to provide an overview of the dental health of people with disabilities in order to understand if their needs are met and to identify their most critical issues as per dentists. A paper and a Google Form platform were used in conducting a survey in Central Italy (the Abruzzo region), by performing an analysis on different points of view as reported by people with disabilities and dentists. The results showed that only 69.2% of dentists treat persons with disabilities. Of these, 73.5% treat less than 10 patients with physical disabilities per year. However, 54% of dentists do not treat people with cognitive impairment and a poor ability to collaborate during treatment. More than 80% of respondent dentists report that people with disabilities do not have good oral hygiene. On the other hand, 49.1% of people with disabilities (or their caregivers in cases where the patient was unable to answer) report that they rarely or never go to the dental office. Moreover, when they do go, it is mainly for emergencies. Despite this, respondents are well aware of their dental problems. However, they have difficulties in communicating their dental problems to their dentist. The 50% of dentists who treat people with cognitive impairment do not include them in follow-up, while only 20% of these patients reported being regularly recalled. This illustrates the importance of the implementation of follow-up. In addition, training courses could help clinicians to reduce this gap and create barrier-free dental offices.
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Cuidadores , Pessoas com Deficiência , Assistência Odontológica , Odontólogos , Humanos , Itália , Inquéritos e QuestionáriosRESUMO
The novel Coronavirus Disease 2019 (COVID-19) pandemic has renewed attention to aerosol-generating procedures (AGPs). Dental-care workers are at high risk of contamination by SARS-CoV-2. The aim of this study was to evaluate the efficacy of standard saliva ejectors and natural ventilation in reducing particulate matter (PM) concentration during different routine dental procedures in the pandemic period. The DustTrak monitor was used to measure PM1, PM2.5, PM10, and breathable (<4 microns) total dust during 14 procedures performed with and without the presence of natural ventilation in a dental unit. Moreover, measurements were performed near the practitioners or near the standard saliva ejectors during the different procedures. In the latter condition, reduced levels of PM10 were recorded (82.40 ± 9.65 µg/m3 vs. 50.52 ± 0.23 µg/m3). Moreover, higher levels of PM (53.95 ± 2.29 µg/m3 vs. 27.85 ± 0.14 µg/m3) were produced when the dental unit's windows were open. At the same time, the total level of PM were higher during scaling than during other procedures (data suggest not to adopt natural ventilation-both window and door opened-during dental procedures). It was also demonstrated that the use of standard saliva ejectors can considerably reduce the total released amount of PM10.
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COVID-19 , Pandemias , Aerossóis , Odontologia , Humanos , SARS-CoV-2 , SalivaRESUMO
Obstructive sleep apnea syndrome (OSAS) is a sleep breathing disorder that often remains undiagnosed and untreated. OSAS prevalence is increasing exponentially. Starting on the dentist's role as an epidemiological and diagnostic "sentinel", the purpose of this study was to assess the prevalence of OSAS. The clinical diaries of 4659 patients were reviewed through a single-center retrospective analytic study. Descriptive statistical analysis was performed. Only 0.26% of patients reported to suffer from sleep apnea and were then diagnosed with OSAS. It was found that, out of 4487 patients, 678 suffered from hypertension (14.80%), 188 from gastro-esophageal-reflux-disease (GERD = 4.10%) and 484 from gastritis (10.78%). These results could be related to a difficult diagnosis of OSAS and to the absence of a dedicated section on sleep disorders in medical records. Therefore, the introduction of a question dedicated to sleep disorders, the administration of questionnaires (such as the STOP-BANG questionnaire) for early diagnosis, a multidisciplinary approach and pneumological examination could support the dentist in identifying patients at risk of OSAS.
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Síndromes da Apneia do Sono , Apneia Obstrutiva do Sono , Humanos , Prevalência , Estudos Retrospectivos , Apneia Obstrutiva do Sono/epidemiologia , Inquéritos e QuestionáriosRESUMO
Oral health care can be a difficult experience for a child with Autism Spectrum Disorder (ASD), for their family and for the dentist. The purpose of this study is to provide an understanding of the challenges experienced by the three aforementioned figures during oral care treatment. A cohort of 275 parents of typical development children (TD), 57 parents of children with ASD (3-15 years old) and by 61 dentists, completed two different multiple choices questionnaires. The data obtained show a great difficulty in the treatment of children with ASD as seen by the dentists and by the parents. This is due to: caregivers' demographic issues; difficulties encountered before and during the dental examination; scarce presence of experts in ASD treatment.
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Transtorno do Espectro Autista/psicologia , Assistência Odontológica/psicologia , Odontólogos/psicologia , Pais/psicologia , Adolescente , Criança , Pré-Escolar , Feminino , Serviços de Saúde para Pessoas com Deficiência , Humanos , Itália , Masculino , Inquéritos e QuestionáriosRESUMO
Adhesive restorations have been shown to guarantee excellent performance and longevity, although this comes with some disadvantages. Among these, the vulnerability of dentine to different agents has been widely evaluated. The aim of this study was to evaluate the possible penetration of impression materials into freshly cut dentine. Dentine from 27 teeth was impressed with polyether (Impregum Penta L) (nine teeth) and with polyvinyl siloxane (Aquasil Ultra LV) (nine teeth). The surface of nine teeth after the impressions were used as the control. Specifically, the extroflections caused by the imprinting of the dentinal tubules on the impression material, the so-called impression tags, were measured. Furthermore, the presence of the material inside the tubules was examined. Scanning electron microscopy analysis showed material tags for all of the experimental groups. The mean lengths (±SD) were 22.6 (±11.0) µm for polyether, 21.8 (±12.8) µm for polyvinyl siloxane and 11.3 (±7.0) µm for the tooth control, with mean diameters (±SD) of 2.8 (±0.5), 2.4 (±0.7) and 3.1 (±0.7) µm, respectively. Fractal analysis showed fractal dimensions of 1.78 (±0.03), 1.77 (±0.03) and 1.71 (±0.03), respectively. These data demonstrated that the impression materials can remain inside the dentinal tubules, which can adversely affect the adhesive procedures.
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The COVID-19 pandemic has affected lives and professions worldwide. We aimed to determine the behavior of dentists during the lockdown in Central Italy through an online survey. We demonstrated that the most frequent of urgencies, not otherwise manageable through telemedicine, was dental pulp inflammation. Although a statistically significant increase in the use of some of the personal protective equipment (PPE) from pre to during lockdown was shown, dentists were afraid of being infected during the dental procedures. Moreover, we showed that digital dentistry, telemedicine, use of the rubber dam, distancing of the appointments and further structural changes at the dental office are necessary to reduce the contagion among dentists and patients. No significant differences were shown between gender.
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Infecções por Coronavirus/epidemiologia , Consultórios Odontológicos/organização & administração , Consultórios Odontológicos/estatística & dados numéricos , Pneumonia Viral/epidemiologia , Betacoronavirus , COVID-19 , Controle de Doenças Transmissíveis/organização & administração , Doenças da Polpa Dentária/epidemiologia , Medo , Humanos , Itália/epidemiologia , Pandemias , Equipamento de Proteção Individual/provisão & distribuição , SARS-CoV-2 , Inquéritos e Questionários , Telemedicina/organização & administraçãoRESUMO
Dentine pretreatment through sandblasting procedures has been widely studied but no curve test results are currently available. Thus, the aim herein was to in vitro compare the adhesive strength in sandblasted or not samples using a universal testing machine. Thirty -two bovine teeth were divided into two groups, namely test (n = 16 bars), sandblasting with aluminum oxide particles (50 µm) was performed before the adhesion procedures), and control (n = 16 bars), where no sandblasting procedure was performed. A bi-material curve test was used to evaluate the characteristics of the dentine pretreatment in terms of tensile stress and fracture strength. A scanning electron microscope (SEM) was used to analyze the fracture topography in the composite, bonding, dentin, and at the relative interfaces. The results demonstrated a statistically significant difference between the two groups in terms of tensile stress at maximum load showing values of 84.300 ± 51.342 MPa and 35.071 ± 16.609 MPa, respectively for test and control groups (p = 0.033). Moreover, a fracture strength test showed values of 18.543 ± 8.145 MPa for test and 8.186 ± 2.833 MPa for control group (p = 0.008). In conclusion, the sandblasting treatment of the dentine significantly influenced the mechanical resistance of the adhesion in this in vitro study.
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Marginal bone loss (MBL) is a key factor in long-term implant success rate. Among the different factors that influence MBL, it is the different implant shoulder designs, such as scalloped or non-scalloped, which have been widely studied on screw retained but not on cemented retained implants. Thus, the aim of the present study was to evaluate the MBL around scalloped and non-scalloped cemented retained dental implants after 4 years of loading, in humans. A total of 15 patients were enrolled in the present study. A radiographic and clinical examination was performed after implant placement (T0) and after 4 years from it (T1). The results demonstrated a differential MBL (T1-T0) of 2.436 ± 1.103 mm and 1.923 ± 1.021 mm, respectively for test (scalloped) and control (non-scalloped) groups with a statistically significant difference between them. On the other hand, no statistically significant differences were found between the groups in terms of prosthetic complication and abutment decementation, whilst ceramic crowns chipping was shown in both groups. In conclusion, the use of a scalloped platform did not provide better results on the maintenance of MBL after 4 years follow-up. In this study, this probably was determined by multiple factors, among which was the subcrestal insertion of scalloped implants.
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Although, the high success rate of implant rehabilitation treatment, the biological complications such as bone loss and peri-implantitis are still present. The creation of a coronal biological seal between the implant and the oral tissues seems to be a crucial point on preserving dental implants. The objective of this study was to immunohistochemically analyze the behavior of peri-implant soft tissues around a new implant healing-abutment surface on humans. A total of 30 soft tissue biopsies were collected after a healing period of 30 (±7) days, to analyze the expression of inflammatory (cluster of differentiation 63 (CD63), human neutrophil peptides 1-3 (HPN1-3)) and junctional (E-cadherin, occludin, and ß-catenin) markers, on soft tissues around laser treated and machined alternated healing abutments. The evaluation demonstrated the whole area of the soft tissues adherent to the laser treated surface with a regular morphology. While several stress hallmarks in correspondence of machined surfaces were shown such as: a) An irregular, disrupted, and discontinued basal membrane with an increased inflammation evident both the epithelial and connective tissues; b) the absence or defective proper keratinization process of the external layer, and c) damages in the cell to cell interaction. In conclusion, the laser treated surface is preferable to maintain the integrity and functionality of the gingiva epithelium.
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Microbial contamination could compromise the stability of dental implants increasing the risk of inflammatory reactions in the surrounding soft tissues. In this human, randomized, double-blind, clinical study, the presence of Porphyromonas gingivalis on the healing abutment and the inflammatory infiltrate surrounding peri-implant soft tissues were investigated. Experiments were done in order to clarify the effect of 0.20% chlorhexidine (CHX) versus placebo, applied during each rehabilitation stage. Thirty patients (15 per group) were included. The load of adhering P. gingivalis on the healing screw were quantified by quantitative Polymerase Chain Reaction (qPCR) Taq-Man. Immunohistochemical analysis was carried out on the gingival biopsy. Moreover, clinical data were recorded. Analysis of variance and the Holm-Sidak test was used to evaluate differences between groups. The results showed a significant low presence of P. gingivalis load in healing abutments belonging to the 0.20% CHX group. Overall, the differences in terms of P. gingivalis DNA copy number between two groups were statistically significant (p < 0.01). All implants showed very low plaque and bleeding scores, but the placebo group appeared to have the highest expression of inflammation markers for T Lymphocytes, B Lymphocytes and macrophages Cluster definitions (CD3, CD20 and CD68). The use of 0.20% CHX could be recommended in all clinical procedures as it reduces significantly P. gingivalis load and host inflammatory response around implants.
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In recent years, Zirconia-reinforced Lithium Silicate ceramic (ZLS), combining lithium-silicate and zirconia features, has shown to have excellent mechanical and aesthetic characteristics. Thus, the aim of this study was to compare the fracture strength of ZLS single crowns cemented with two different cementation techniques. Twenty crowns were realised and cemented on teeth replicas achieved from an extracted premolar human tooth. The samples were divided into two groups of 10 specimens each, Glass-ionomeric cement (GIC) group and Self-Adhesive Resin Cement (ARC) group. The mechanical test was performed using a universal testing machine. The specimens were then evaluated with a scanning electron microscope (SEM) to identify for all crowns and related abutments the pattern of fracture after the breaking point. The data obtained were statistically analysed. The mean fracture toughness values and standard deviations (±SD) were 2227 ± 382 N and 3712 ± 319 N respectively for GIC and ARC groups. In fact, t-test showed a statistically significant difference between the two groups (p < 0.001). Moreover, the SEM results demonstrated portions of abutments still attached to the crown fragments in the ARC group, whilst these were not present in the GIC group. Within the limitations of this study, these results suggest the use of adhesive cementation for ZLS crowns, which significantly increase the compressive strength of ZLS restorations compared to GIC.
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Immediate dentin sealing (IDS) is an advantageous approach for realizing adhesive restorations, but it interferes with the polymerization of impression material due to the oxygen-inhibition layer (OIL), which leaves residues of impression material on the teeth. The aim of this study is to identify a clinical surface cleaning protocol after IDS in order to achieve defect-free impressions. Sixty extracted human teeth were cut to expose fresh dentin and the IDS protocol was performed. Samples were divided into six groups where different surface cleaning protocols were made before taking impressions: G1S and G1P groups, IDS and silicone (S) or polyether (P) impressions; G2S and G2P, treatment with prophy paste and impressions; G3S and G3P, final cleaning phase with surfactant agent and impressions. Teeth were evaluated with a scanning electron microscope to identify the areas (expressed in mm2) where residual impression material was present. The results demonstrate a reduction of residues in the G2 groups and the total disappearance in G3 groups with statistically significant differences between them. Superficial cleaning protocols with the prophy paste and surfactant agent lead to the elimination of the interaction with impression materials and OIL. These results suggest a safe clinical protocol for obtaining defect-free impressions after IDS.