Comparative surface detail reproduction for elastomeric impression materials: Study on reproducibility performance

For dental impression of a prepared tooth, the goal is a void-free negative representation from which an accurate cast of a tooth and its surrounding tissue can be reproduced. This in-vitro study assessed and compared the reproduction accuracies of surface detail obtained with three different dental elastomeric impression materials: vinyl polysiloxane (VPS), vinyl polyether silicone (VPES), and polyether (PE). A stainless-steel model with two abutments was used, with impressions taken 10 times for each material, for 20 abutment impressions per group, using a two-phase, one-step technique (heavy body/light body). The impressions were removed and assessed for numbers of enclosed voids and open voids visible on the surface. The defect frequency was 95% for impressions with the VPS and VPES materials, and 30% for the PE material. No significant differences were seen for number of impressions with defects for VPS versus VPES. Significant differences were seen for VPS and VPES versus the PE material (P <.05). No significant differences were seen for the defect type distributions across these three impression materials. The PE impression material showed better accuracy for reproduction of surface detail of these dental impressions compared to the VPS and VPES impression materials.

A 10-year retrospective comparative human study on screw-retained versus cemented dental implant abutments

The aim of this 10-year retrospective study was to evaluate the long-term reliability, survival rate and mechanical and biological complications of single-crown implant rehabilitations with two different types of fixture-abutment connections: screw-retained abutments (SRAs) with internal hexagonal connection, and cemented retained abutments (CRAs). A total of 300 single implant-supported crowns were analysed, which had been inserted between 2004 and 2007. Patients were classified according to two groups: the SRA group (n = 150) and the CRA group (n = 150). The primary outcome was marginal bone loss (MBL) on peri-apical radiographs. Bleeding on probing (BOP) and probing depth (PD) were also evaluated. Moreover, prosthetic complications were recorded. Analysis of variance (ANOVA) was used to evaluate the differences between the groups. The overall implant failure rate was 4.2%. The overall positive BOP index was 81.9% of the sites under investigation, as 83.4% for SRA and 80.4% for CRA. Moreover, >5 mm PD demonstrated a rate of 21.0% for CRA, and 13.8% for SRA. The primary outcome of mean MBL was 2.09±1.07 mm for SRA and 1.54±1.20 mm for CRA. Analysis of variance of MBL showed statistical significance for the difference between these two groups (P less than 0.001). For the mechanical aspects, an overall 12.5% of complications occurred. No implant or abutment fractures were recorded. Although complications occurred, the results from this 10-year retrospective study show that these two methods have positive long-term follow-up. With MBL significantly greater for the SRA group than the CRA group, the clinical use of CRA is encouraged in terms of the lower bone resorption rate.

Immunohistochemical study of osteopontin in oral squamous cell carcinoma allied to fractal dimension

The aim of the study was to consider a possible correlation between the intensity of expression of osteopontin and grading established by the pathologist. Furthermore, a correlation was investigated between the increase of fractal dimension and osteopontin in order to use this marker as an early and reliable diagnostic tool for the degree of cell transformation in oral squamous carcinoma. Ten histologically healthy oral samples and sixty-four primary oral squamous cell carcinomas specimens were analysed by a single pathologist. Immunohistochemical analysis and Fulgen stain were performed in order to evaluate intensity of expression of osteopontin and fractal dimension. Data obtained were presented as mean and standard deviation and processed for the statistical analysis. Ostepontin expression revealed a statistical significance between groups (P less than 0.001). Fractal dimension in oral squamous cell carcinoma groups vs controls revealed statistically significant differences (P less than 0.001). The fractal dimension value and the osteopontin expression were compared, using two-dimensional scatter. The correlation was relevant in the G3 group. The results demonstrated a correlation between the growths of osteopontin expression and nuclear abnormality measured by fractal dimension. These results support the hypothesis that the level of osteopontin expression might be used as a marker for the evaluation of oral squamous cell carcinoma differentiation. Osteopontin and fractal dimension could support the histological grading to increase the predictability of the diagnosis, choices of treatment procedure and long-term prognosis.

Multimodal-3D imaging based on μMRI and μCT techniques bridges the gap with histology in visualization of the bone regeneration process

Bone repair/regeneration is usually investigated through X-ray computed microtomography (μCT) supported by histology of extracted samples, to analyse biomaterial structure and new bone formation processes. Magnetic resonance imaging (μMRI) shows a richer tissue contrast than μCT, despite at lower resolution, and could be combined with μCT in the perspective of conducting non-destructive 3D investigations of bone. A pipeline designed to combine μMRI and μCT images of bone samples is here described and applied on samples of extracted human jawbone core following bone graft. We optimized the coregistration procedure between μCT and μMRI images to avoid bias due to the different resolutions and contrasts. Furthermore, we used an Adaptive Multivariate Clustering, grouping homologous voxels in the coregistered images, to visualize different tissue types within a fused 3D metastructure. The tissue grouping matched the 2D histology applied only on 1 slice, thus extending the histology labelling in 3D. Specifically, in all samples, we could separate and map 2 types of regenerated bone, calcified tissue, soft tissues, and/or fat and marrow space. Remarkably, μMRI and μCT alone were not able to separate the 2 types of regenerated bone. Finally, we computed volumes of each tissue in the 3D metastructures, which might be exploited by quantitative simulation. The 3D metastructure obtained through our pipeline represents a first step to bridge the gap between the quality of information obtained from 2D optical microscopy and the 3D mapping of the bone tissue heterogeneity and could allow researchers and clinicians to non-destructively characterize and follow-up bone regeneration.

Anti-inflammatory steroid use in impacted third molar surgery: a systematic review

Oral surgery procedures involve traumatization of mucosal and bony tissues, and lengthy interventions can lead to inflammatory post-operative sequelae. In the bony tissues in particular, the inflammatory processes can affect healing. Modern drug therapies provide valid support for lowering the risk of occurrence of post-operative inflammatory signs. The two main types of agents used are nonsteroidal anti-inflammatory drugs and/or corticosteroids, which act on two different molecular pathways in the inflammatiory process. The aim of this systematic review is to examine the different corticosteroids used in oral surgery procedures, their indications for use, and their route of administration, to provide the clinician with a useful scheme for correct pharmacological management of post-operative inflammation. To identify studies eligible for inclusion in this systematic review, we performed a literature search up to April 2017 of the electronic databases, considering published papers from 2007 to 2017. The search terms included steroids, third molar, oral surgery, RCT [randomized controlled trial], human, and clinical trial. Only articles in English language were considered.

Instant loading with intraoral welding technique and PRAMA implants: a new prosthetic approach

When splinting multiple implants passive fit of the framework should be achieved to avoid excessive force distribution on the implants. Recently, a protocol was suggested for immediate loading of multiple implants by welding a titanium bar to implant abutments directly in the oral cavity so as to create a customized, precise and passive metal-reinforced provisional restoration. The intraoral welding technique subsequently proves to be a successful option in the full-arch immediate restorations of the mandible and maxilla. The aim of this article is to present a case report in which a new prosthetic approach, using trans-mucosal implants, is described. Dental implants are instantly loaded with a provisional prosthesis supported by an intraoral welded titanium framework to obtain a precise passive fit of the immediate loaded prosthesis.

Comparative molecular analysis of bacterial species associated with periodontal disease

Periodontal disease is an inflammatory disorder affecting the supporting teeth structures, including gingiva, periodontal ligament and alveolar bone, causing loss of connective tissue, reabsorption of alveolar bone and formation of periodontal pockets. The aim of this study is to find a correlation between bacterial growth and periodontal disease. Fifty-seven patients aged between 21 and 65 years, median age 46 years, were enrolled. According to gingival pocket depth, ranging from 3 to 7 mm, patients were divided into two groups: the first (30 patients, 53%) with deep pockets ³ 5 mm and the second (27 patients, 47%) less than 5 mm. The samples taken were processed for microbiological analysis by absolute quantitative real-time Taq-Man technique. Patients affected by periodontal disease were 32 (56%) and patients with gingival bleeding were 35 (61%). This data showed that the presence, the type and the bacterial load in gingival pockets were strongly correlated with gingival depth, periodontal disease and gingival bleeding. Quantitative microbiological analysis is a key point to improve patient compliance, allowing to choose the specific antibiotic treatment. avoiding antibiotic resistance and ensuring the successful outcome of therapy for periodontal disease.

Mandibular third molar displaced in the sublingual space: clinical management and medicolegal considerations

This paper describes the management of a failed mandibular third molar extraction, resulting in tooth displacement in the sublingual space, the discussion of the diagnosis, surgery and medico-legal considerations. A 28-year-old male patient underwent an unsuccessful attempt of the 4.8 tooth extraction. The clinician lost visual contact after luxation and the patient was not recalled for post-operative follow-up. After 24 hours, a severe trismus started. Ortopantomography and cone beam computer tomography revealed the displacement in the sublingual space. The tooth was removed under general anaesthesia with intraoral approach. The follow-up was uneventful and the paraesthetic area on the tongue did not enlarge after the retrieval. The displaced mandibular third molar is a rare but potentially serious complication of extraction. This event should be avoided with correct diagnosis and surgical technique. Cone beam computed tomography was useful to determine the three-dimensional position of the displaced tooth.

A cytotoxic analysis of a sardinian plant extract cream on human oral primary cell cultures: an in vitro study

Wound healing agents support the natural healing process, reduce trauma and likelihood of secondary infections and hasten wound closure. The aim of this work was to evaluate the effect of different concentration of a new Sardinian plant cream (RD7) on two human primary cultures: Periodontal Ligament Stem Cells (hPDLSCs) and Gingival Fibroblasts (hGFs) derived from oral tissues in terms of morphological changes, cell proliferation and wound healing properties. RD7, is an interactive dressing containing phytocomplex derived from Sardinian endemic or not, medicinal plant extracts, with an important anti-radical, anti-inflammatory and antiseptic activity finalized to rapidly promote tissue regeneration and the formation of granulation tissue. hPDLSCs and hGFs were seeded at different concentrations (0.5, 1, 2.5 and 5 mg/ml) of RD7. The cell proliferation and viability was evaluated using colorimetric assays (MTT assay) and trypan blue exclusion test. Meanwhile, the morphological cell changes were evaluated by means of optic (OM) and scanning electronic microscopes (SEM). The induction of the migratory properties was evaluated by means of wound healing assay. In vitro results, using hPDLSCs and hGFs, showed a decrease of cell growth starting at 24 h of incubation, at high concentrations (2.5 mg/ml and 5 mg/ml). This cell growth reduction was associated to evident morphological changes, whilst, at low concentrations (0.5 and 1 mg/ml) a typical unchanged morphology of both hPDLSCs and hGFs was shown. Wound healing assay showed a complete wound full closure occurring after 24 h of treatment in samples treated with low concentration of RD7. The results of the present work indicate that low concentrations of RD7 have no cytotoxicity effect, stimulate cell proliferation and contribute to induce the migratory properties in hPDLSCs and hGFs, therefore it could be considered a new product for use in clinical practice.

Use of Oral Chroma™ in the assessment of volatile sulfur compounds in patients with fixed protheses

Prosthetic rehabilitation improves the patient's quality of life and oral health. The purpose of the present study was to assess the production of volatile sulfur compounds (VSCs) using Oral Chroma™ in patients wearing provisional and permanent fixed prosthesis, who were treated or not, with supportive non-surgical periodontal therapy. A total of 10 healthy patients not affected by periodontal disease and who needed the restoration of at least two edentulous single sites were included in the present study. Registrations of VSCs were carried out with a Gas Chromatograph OralChroma™ (Oral Chroma™, Abimedical, Abilit Corp., Osaka, Japan) one month after placement of the provisional restoration (group 1) and one month after placement of the final restoration (group 3). After each measurement, professional oral hygiene was carried out both on patients with provisional (group 2) and permanent prostheses (group 4) and VSC values were registered. The results showed that there were no statistical significant differences in the VSC quantity between groups with temporary or permanent prostheses. Meanwhile, statistically significant differences were found in VCS values between groups before and after the professional health care session (p less than 0.05). Also it was observed that dimethyl sulphide (CH3)2S was present in all the study groups. The present preliminary study suggests that OralChroma™ produce a comprehensive assessment of VSC in the clinical diagnosis of halitosis and that professional oral hygiene seems to influence VSC production. However, further clinical long-term studies with a larger sample size are necessary for a better understanding of halitosis manifestation in patients wearing provisional and permanent fixed prosthesis.

Copper-zinc superoxide dismutase activity in dental pulp after dental preparation

The superoxide dismutases (SODs) are the major enzymatic defence mechanism against toxic reactive oxygen species generated during normal oxidative metabolism and during the respiratory burst associated with inflammation. To further clarify the potential role of copper-zinc (Cu/Zn)-SOD during inflammation of pulp tissue in humans, the aim was to determine whether significant changes in Cu/Zn-SOD activity occur in healthy dental pulp after dental preparation. The condition of the pulp was assessed using clinical and radiographic evaluation. Thirty systemically healthy patients were the source of the pulp tissue, which was collected by longitudinally grooving and splitting teeth that were matched between the control dental pulp and the prepared tooth (test) dental pulp. Cu/Zn-SOD activity was determined through spectrophotometric methods, with Mann-Whitney tests used to assess the significance of the differences between the groups. The Cu/Zn-SOD activity was 168.2+/-46.4 mU.mg−1 total protein (range: 96-212 mU.mg−1) in the control group, and 328.2+/-84.2 mU.mg−1 total protein (range: 280-420 mU.mg−1) in the test group. The difference between the groups was statistically significant, at P <0.001. These results demonstrate a potential role for Cu/Zn-SOD during dental pulp inflammation in humans after dental preparation.

Influence of titanium laser surface geometry on proliferation and on morphological features of human mandibular primary osteoblasts

The aim of this study is to assess in vitro the proliferation and the morphological changes of primary osteoblast-like cells (HOst) seeded on titanium dish grade 4 and 5 with different roughness and different titanium grade: machined (M), sandblasted (SBT), laser-treated with pitches of 20-microm diameter and 30-microm interpore distance. The titanium disks were divided into two groups: group A (titanium grade 4) and Group B (titanium Grade 5), respectively. Proliferation rate of attached cells was evaluated at different time (24, 48, 72 h and 1 week) by the quantitative colorimetric MTT assay. Our results showed a cell growth decrease evident in M titanium surfaces in both Groups A and B, while the cells seeded on the STB and laser disks displayed an increase of cells growth, more evident in laser titanium surfaces in groups A and B. Morphological changes of the biocomplex cells/titanium was assessed by light, scanning and confocal microscopy. In fact, the microscopic analysis helped to clarify the behavior of the cells in contact with the titanium surfaces, in particular the M surface induced significant morphological changes, which were less evident in the SBT surfaces. Laser-engineered porous titanium surfaces promoted viability and proliferation of the osteoblasts. In particular, hemispherical porosity of 20 microm could be responsible for the higher HOst activation, in terms of cells proliferation, adhesion and morphological features.

Two-step impression/ injection, an alternative putty/ wash impression technique: case report

We here describe a new technique for making a definitive impression that we refer to as the two-step impression/injection technique. This technique initially follows the classical one-step putty/ light-body impression technique with the polymerization of the putty and the light-body compound. This is then followed by the second step: injection of extra-light-body compound into the preparation through a hole in the metal stock tray. The aim of this additional step is to control the wash bulk and minimize the changes that can produce unfavorable impression results. This new two-step impression/injection technique allows displacement of soft tissues, such as the tongue, during the first seating of the putty and wash materials, while in the second step, the extra-light-body compound records all of the finer details without being compressed.

Comparison of the primary stabilities of conical and cylindrical endosseous dental implants: an in-vitro study

The aim of this study is to determine the differences in primary stability between conical and cylindrical dental implants. The insertion and removal torques were the parameters used to measure the primary stability of the implants. Ten conical and cylindrical dental implants were positioned in polyurethane foam blocks to simulate bone density classes D1, D2, D3 and D4. The insertion and removal torques were quantified using a digital torque gauge. The maximum insertion torque and the maximum removal torque measured for the D1 and D4 synthetic bone were significantly higher for the conical implants than the cylindrical implants. In this in-vitro model, conical implants show significantly higher primary stability than cylindrical implants for the D1 and D4 synthetic bone classes.