Comparative in vitro study on biomechanical behavior of zirconia and polyetheretherketone biomaterials exposed to experimental loading conditions in a prototypal simulator.

Zirconia and polyetheretherketone (PEEK) are two biomaterials widely investigated as substitute for metals in oral prosthetic rehabilitation. To achieve a proper biomechanical behavior, the prosthetic biomaterials must ensure a good resistance to loads, as this is a crucial characteristic enabling their use in dental applications. The aim of this study was to investigate differences in the fracture resistance of different biomaterials in an experimental environment: fixed partial dentures (FPDs) screwed in a prototype of biomimetic mandible. 10 Samples of FPDs were allocated in 2 groups (A and B): Group A (n=5) involved FPDs in zirconia-ceramic, and Group B (n=5) involved FPDs in PEEK-composite. The samples were loaded by means of a three-point bending mechanical test, and the load to fracture has been evaluated generating a point-by-point graphics (speed/load and time/deformation). The samples were further analyzed by micro-computed tomography (micro-CT) and described under experimental loading conditions. Zirconia-ceramic FDPs were the samples reporting the worst results, showing a lower value of vertical displacement with respect to PEEK-based samples. The micro-CT results have further confirmed the preliminary results previously described. This in vitro study aims to give analytic data on the reliability of PEEK as a reliable and strong biomaterial for prosthetic treatments.

New Strategies and Instruments for Root Canal Shaping Procedure: An Overview.

Cone-beam computed tomography-based three-dimensional analysis of root canal trajectories and shapes have clearly shown that root canals are more complex in 3D, compared to traditional 2D visualization,1-4 and consequently, these findings affect properties of the nickel-titanium (NiTi) files requiring the following factors.

Decellularized Hydrogels in Bone Tissue Engineering: A Topical Review.

Nowadays, autograft and allograft techniques represent the main solution to improve bone repair. Unfortunately, autograft technique is expensive, invasive and subject to infections and hematoma, frequently affecting both donor sites and surgical sites. A recent advance in tissue engineering is the fabrication of cell-laden hydrogels with custom-made geometry, depending on the clinical case. The use of ECM (Extra-Cellular Matrix)-derived Hydrogels from bone tissue is the new opportunity to obtain good results in bone regeneration. Several micro-engineering techniques and approaches are available to fabricate different cell gradients and zonal structures in hydrogels design, in combination with the advancement in biomaterials selection. In this review, we analyse the stereolithografy, the Bio-patterning, the 3D bioprinting and 3D assembly, the Laser-Induced Forward Transfer Bioprinting (LIFT), the Micro-extrusion bioprinting, the promising Electrospinning technology, the Microfluidics and the Micromolding. Several mechanical properties are taken into account for bone regeneration scaffolds. However, each typology of scaffold presents some advantages and some concerns. The research on biomaterials is the most promising for bone tissue engineering: the new biomimetic materials will allow us to obtain optimal results in the next clinical application of basic research.

Altered transcription of inflammation-related genes in dental pulp of coeliac children.

BACKGROUND: Coeliac disease is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten, and possible relationships between coeliac disease and dental pathogenic conditions during childhood have been poorly investigated. AIM: The dental pulp plays a pivotal role in the immune defence against possible entry of pathogens from teeth, and the aim of this work was to investigate quantitative transcription levels of selected genes (IL-9, IL-11, IL-15, IL-18, IL-21, IL-27, MICA, IFN-γ) coding for pro-inflammatory immune innate activities in the pulp of primary teeth from healthy children and children with coeliac disease. DESIGN: The pulp from primary teeth of 10 healthy children and 10 children with coeliac disease was used to extract RNA and prepare cDNA for quantitative PCR transcription analysis employing commercial nucleotide probes for selected genes. RESULTS: In children with coeliac disease, the genes coding for pro-inflammatory cytokines IFN-γ, IL-11, IL-18, and IL-21 were significantly overexpressed, suggesting the possible importance of these cytokines in the relationships between coeliac disease and dental disorders. CONCLUSION: For the first time, we reported in dental pulp of children possible relationships between coeliac disease and modulation in transcription of cytokine-dependent inflammatory activities.

Today prospects for tissue engineering therapeutic approach in dentistry.

In dental practice there is an increasing need for predictable therapeutic protocols able to regenerate tissues that, due to inflammatory or traumatic events, may suffer from loss of their function. One of the topics arising major interest in the research applied to regenerative medicine is represented by tissue engineering and, in particular, by stem cells. The study of stem cells in dentistry over the years has shown an exponential increase in literature. Adult mesenchymal stem cells have recently been isolated and characterized from tooth-related tissues and they might represent, in the near future, a new gold standard in the regeneration of all oral tissues. The aim of our review is to provide an overview on the topic reporting the current knowledge for each class of dental stem cells and to identify their potential clinical applications as therapeutic tool in various branches of dentistry.

Importance of fetal MRI in evaluation of craniofacial deformities.

AIM: This retrospective study aims at demonstrating the importance of a correct and detailed early diagnosis of craniomaxillofacial malformations affecting the fetus, which would (1) allow improvement in ultrasonography (US) diagnosis, (2) help in planning the therapeutic-surgical procedure, and (3) improve handling of the pathology by the families. MATERIALS AND METHODS: Between 2008 and 2011, a sample of 28 fetuses was selected, all with an ultrasound diagnosis of cleft lip (cheiloschisis-CL) and cleft lip and palate (palatoschisis-CLP) and craniofacial malformation, whose mothers had all underwent ultrasound diagnostic examinations and nuclear magnetic resonance (MRI). All cases were submitted to US examination between the 12th and 19th week of pregnancy, US-3D examination performed by a specialist radiologist between the 19th and 22nd week, and MRI examination between the 23rd and 33rd week of pregnancy. RESULTS: The MRI confirmed the ultrasound diagnosis of 16/28 cases and added information in 11/28 cases, and in 1 (1/28) case, the MRI denied previous CL-CLP ultrasound diagnosis. Moreover, in this study MRI improved the analysis of the entire morphology of the fetuses in cases when syndromic involvement with the involvement of other organs needs to be determined. CONCLUSIONS: The MRI method in fetal patients allows to obtain more details regarding the CL-CLP studied, allowing the medical-surgical team to plan, before the birth, the type of postnatal assessment and surgery to be performed, thus minimizing the impact on neonatal health and improving quality of life of both the patient and his family.

PReferentially Expressed Antigen in MElanoma (PRAME): preliminary communication on a translational tool able to early detect Oral Malignant Melanoma (OMM).

Oral malignant melanoma (OMM) has a prevalence less than 1% of all melanomas and it commonly develops on the oral mucosa following a slow and unspecific transformation of unstable melanocytic lesions, often resulting in a diagnostic delay. The marker PReferentially Expressed Antigen in MElanoma (PRAME) seems to be a valid tool to investigate the biological and histological nature of cutaneous melanocytic lesions, but to date its use to characterize pigmented lesions in the oral cavity is largely unexplored. The aim of this study was to create preliminary knowledge on the PRAME expression in OMM, and to compare its expression respect to other dysplastic pigmented lesions of the oral cavity. Interestingly, PRAME has been demonstrated to be reliable in the clinical conditions investigated in our pilot study; in fact, it has clearly differentiated the cases of Melanoma, which showed diffuse and intense positivity (score 6+/7+) to PRAME, from the other melanocytic nevi, which resulted to be mainly negative to PRAME. This means a better differential diagnosis, a reliable early diagnosis and a proper clinical/surgical management of the oncological lesions. In conclusion, PRAME can be a valid qualitative marker for differential diagnosis, not only in cutaneous melanomas, but also in malignant melanoma of the entire head and neck area.

Platelet Rich Fibrin (P.R.F.) in reconstructive surgery of atrophied maxillary bones: clinical and histological evaluations.

INTRODUCTION: Maxillary bone losses often require additional regenerative procedures: as a supplement to the procedures of tissue regeneration, a platelet concentrate called PRF (Platelet Rich Fibrin) was tested for the first time in France by Dr. Choukroun. Aim of the present study is to investigate, clinically and histologically, the potential use of PRF, associated with deproteinized bovine bone (Bio-Oss), as grafting materials in pre-implantology sinus grafting of severe maxillary atrophy, in comparison with a control group, in which only deproteinized bovine bone (Bio-Oss) was used as reconstructive material. MATERIALS AND METHODS: 60 patients were recruited using the cluster-sampling method; inclusion criteria were maxillary atrophy with residual ridge < 5mm. The major atrophies in selected patients involved sinus-lift, with a second-look reopening for the implant insertion phase. The used grafting materials were: a) Bio-Oss and b) amorphous and membranous PRF together with Bio-Oss. We performed all operations by means of piezosurgery in order to reduce trauma and to optimize the design of the operculum on the cortical bone. The reopening of the surgical area was scheduled at 3 different times. RESULTS: 72 sinus lifts were performed with subsequent implants insertions.We want to underline how the histological results proved that the samples collected after 106 days (Early protocol) with the adding of PRF were constituted by lamellar bone tissue with an interposed stroma that appeared relaxed and richly vascularized. CONCLUSIONS: The use of PRF and piezosurgery reduced the healing time, compared to the 150 days described in literature, favoring optimal bone regeneration. At 106 days, it is already possible to achieve good primary stability of endosseous implants, though lacking of functional loading.

Oxia Planum: The Landing Site for the ExoMars "Rosalind Franklin" Rover Mission: Geological Context and Prelanding Interpretation.

The European Space Agency (ESA) and Roscosmos ExoMars mission will launch the "Rosalind Franklin" rover in 2022 for a landing on Mars in 2023.The goals of the mission are to search for signs of past and present life on Mars, investigate the water/geochemical environment as a function of depth in the shallow subsurface, and characterize the surface environment. To meet these scientific objectives while minimizing the risk for landing, a 5-year-long landing site selection process was conducted by ESA, during which eight candidate sites were down selected to one: Oxia Planum. Oxia Planum is a 200 km-wide low-relief terrain characterized by hydrous clay-bearing bedrock units located at the southwest margin of Arabia Terra. This region exhibits Noachian-aged terrains. We show in this study that the selected landing site has recorded at least two distinct aqueous environments, both of which occurred during the Noachian: (1) a first phase that led to the deposition and alteration of ∼100 m of layered clay-rich deposits and (2) a second phase of a fluviodeltaic system that postdates the widespread clay-rich layered unit. Rounded isolated buttes that overlie the clay-bearing unit may also be related to aqueous processes. Our study also details the formation of an unaltered mafic-rich dark resistant unit likely of Amazonian age that caps the other units and possibly originated from volcanism. Oxia Planum shows evidence for intense erosion from morphology (inverted features) and crater statistics. Due to these erosional processes, two types of Noachian sedimentary rocks are currently exposed. We also expect rocks at the surface to have been exposed to cosmic bombardment only recently, minimizing organic matter damage.

Flapless Cone Beam Computed Tomography-Guided Implant Surgery with Contextual Transcrestal Sinus Lift Augmentation Using New Bone Compactor Tools.

In the present paper, the authors present a case report of premolar edentulism in the upper jaw treated through a guided flapless oral implant surgery with contextual crestal sinus lift, performed with a system of manual screw-tapered bone expanders (B&B Dental, San Benedetto, BO, Italy). The surgery was planned by means of dedicated software, through which the data obtained from the CBCT and from intraoral scanner impression were matched, with consequent production of a surgical template. The proposed surgical procedure is minimally invasive, very simple, and fast and ensures good comfort for the patient by avoiding the elevation of mucoperiosteal flaps and uncomfortable malleting maneuvers. In addition, the presented method shows a good degree of correspondence between the ideal position of the implant in the planning phase and the actual one detectable after the surgery.

Horizontal Ridge Augmentation and Contextual Implant Placement with a Resorbable Membrane and Particulated Anorganic Bovine Bone-Derived Mineral.

Alveolar ridge deficiency is considered a major limitation for successful implant placement. Various approaches have been developed to horizontal augmentation of bone volume. This case report presents the medium-term results of one-stage guided bone augmentation using an anorganic bovine bone (70%) and autologous bone (30%), placed in layers, in association with resorbable collagen membrane for a subsequent implant placement. The patient presented with a localized horizontal ridge defect in the posterior zone of the jaw. The clinical and radiographic presentations, as well as relevant literature, are presented.

Age estimation by the Cameriere's normalized measurements (CNM) of the single permanent mandibular tooth on a panoramic radiograph.

In this study Cameriere's normalized measurements (CNM) of a single mandibular tooth were evaluated for age estimation on a sample of ortopantomographies (OPTs) of 2223 Italian children aged between 4 and 15years. Dental maturity was radiographically evaluated by CNM of the seven left permanent mandibular teeth (CNMi=Ai/Li, i=1,…,7); in monoradicular teeth, the distance (Ai, i=1,…,5) between the inner sides of the open apex was measured while in biradicular teeth (Ai, i=6, 7), the sum of the distances between the inner sides of the two open apices was calculated. Ai was normalized by the tooth length (Li, i=1,…,7). The intra- and inter-observer agreement of CNM measurements was almost perfect. Overall, analyzed mandibular teeth finished their development up to the age of 13, but the distribution of CNM varied among different locations. The final models included a tooth-specific CNM as the independent variable and explained from 76% (second molars) to 39% (first incisors) of the variance in chronological age. The bias and accuracy of these models, when applied to real-life data with no age limitation, were within acceptable range of differences in the forensic anthropology of children. Specifically, in all models mean of absolute differences between estimated and real age was within one year (0.67 for first incisors to 1.00 for canines). In conclusion this study showed that all mandibular teeth do not have equal applicability for age estimation suggesting that further evaluation on different samples is necessary to evaluate the usefulness of a single mandibular tooth for age estimation.

Potential Use of Human Periapical Cyst-Mesenchymal Stem Cells (hPCy-MSCs) as a Novel Stem Cell Source for Regenerative Medicine Applications.

Mesenchymal stem cells (MSCs) are attracting growing interest by the scientific community due to their huge regenerative potential. Thus, the plasticity of MSCs strongly suggests the utilization of these cells for regenerative medicine applications. The main issue about the clinical use of MSCs is related to the complex way to obtain them from healthy tissues; this topic has encouraged scientists to search for novel and more advantageous sources of these cells in easily accessible tissues. The oral cavity hosts several cell populations expressing mesenchymal stem cell like-features, furthermore, the access to oral and dental tissues is simple and isolation of cells is very efficient. Thus, oral-derived stem cells are highly attractive for clinical purposes. In this context, human periapical cyst mesenchymal stem cells (hPCy-MSCs) exhibit characteristics similar to other dental-derived MSCs, including their extensive proliferative potential, cell surface marker profile and the ability to differentiate into various cell types such as osteoblasts, adipocytes and neurons. Importantly, hPCy-MSCs are easily collected from the surgically removed periapical cysts; this reusing of biological waste guarantees a smart source of stem cells without any impact on the surrounding healthy tissues. In this review, we report the most interesting research topics related to hPCy-MSCs with a newsworthy discussion about the future insights. This newly discovered cell population exhibits interesting and valuable potentialities that could be of high impact in the future regenerative medicine applications.

Childhood overweight-obesity and periodontal diseases: is there a real correlation?

OBJECTIVE: The association between obesity and periodontitis has been extensively investigated in adults but not in young people. The aim of this study was to examine the association between overweight-obesity and periodontal disease in pediatric subjects. METHODS: Controlled cross-sectional study involving 100 school children of both gender (50 M and 50 F) between 7 and 12 years of age (mean age 9,19±1,57). Two groups were formed based on Body Mass Index value: test group with BMI ≥ 25 Kg/m2 and control group with BMI ≤ 24 Kg/m2. Diet intake and oral hygiene habits were recorded by a specific questionnaire and the periodontal clinical parameters were evaluated. RESULTS: The periodontal examination in the control group revealed a full-mouth plaque score (FMPS) value equal to 21.86% against 50.08% in the group of patients overweight/obese; the full-mouth bleeding score (FMBS) in the control group amounted to 12.7% against 26.24% of test group. No patient in either group included in the study presented a probing pocket depth (PPD) ≥3, so a significant difference regarding this value was not found. Regarding the frequency and quantity of food consumption, the number of obese patients who did not follow a balanced diet largely exceeded the number of normal-weight patients (70 versus 20%). CONCLUSIONS: These results focus the attention on the negative impact of obesity on gingival health in young subjects, probably due to a combination of metabolic and inflammatory profiles and the result of a careless attitude towards prevention diseases of the oral cavity.

Third molar development by measurements of open apices in an Italian sample of living subjects.

The aim of this study is to analyse the age-predicting performance of third molar index (I3M) in dental age estimation. A multiple regression analysis was developed with chronological age as the independent variable. In order to investigate the relationship between the I3M and chronological age, the standard deviation and relative error were examined. Digitalized orthopantomographs (OPTs) of 975 Italian healthy subjects (531 female and 444 male), aged between 9 and 22 years, were studied. Third molar development was determined according to Cameriere et al. (2008). Analysis of covariance (ANCOVA) was applied to study the interaction between I3M and the gender. The difference between age and third molar index (I3M) was tested with Pearson's correlation coefficient. The I3M, the age and the gender of the subjects were used as predictive variable for age estimation. The small F-value for the gender (F = 0.042, p = 0.837) reveals that this factor does not affect the growth of the third molar. Adjusted R(2) (AdjR(2)) was used as parameter to define the best fitting function. All the regression models (linear, exponential, and polynomial) showed a similar AdjR(2). The polynomial (2nd order) fitting explains about the 78% of the total variance and do not add any relevant clinical information to the age estimation process from the third molar. The standard deviation and relative error increase with the age. The I3M has its minimum in the younger group of studied individuals and its maximum in the oldest ones, indicating that its precision and reliability decrease with the age.

Surgical Management of Compound Odontoma Associated with Unerupted Tooth.

Odontomas represent the most common type of odontogenic benign jaws tumors among patients younger than 20 years of age. These tumors are composed of enamel, dentine, cementum, and pulp tissue. According to the World Health Organization classification, two distinct types of odontomas are acknowledged: complex and compound odontoma. In complex odontomas, all dental tissues are formed, but appeared without an organized structure. In compound odontomas, all dental tissues are arranged in numerous tooth-like structures known as denticles. Compound odontomas are often associated with impacted adjacent permanent teeth and their surgical removal represents the best therapeutic option. A case of a 20-year-old male patient with a compound odontoma-associated of impacted maxillary canine is presented. A minimally invasive surgical technique is adopted to remove the least amount of bone tissue as far as possible.

How accurate is CBCT in measuring bone density? A comparative CBCT-CT in vitro study.

PURPOSE: Recently, cone beam computed tomography (CBCT) has become widely used for oral and maxillofacial imaging. Twenty dry mandibles were CBCT and conventional multislice CT scanned to evaluate if there is a statistically significant difference between the bone density values they produce, defined as gray density values, and to determine any correlation between them. MATERIALS AND METHODS: Using software and a radiographic template, the CT and CBCT scan images were overlapped, and two data sets were created, each one giving the respective gray values (voxel value [VV] or Hounsfield unit [HU]) of the same area with the same spatial coordinates. For the statistical analysis, t-test, Pearson's correlation, and Pearson's r were used. RESULTS: The differences between the CBCT (VV) and CT (HU) gray density values were statistically significant (p ≤ .05), whereas the Pearson's correlation coefficients and Pearson's r-values demonstrated a statistically significant linear correlation between VV and HU gray density values. CONCLUSION: The lower radiation dose and reduced costs of CBCT make this a useful substitute for CT; however, this study has shown that, in order to more accurately define the bone density with CBCT, a conversion ratio needs to be applied to the VV.

Dental and maxillofacial alterations in patients affected from odontochondrodysplasia: a rare case report and review of literature.

INTRODUCTION: This paper has evaluated the dental and or facial disorders associated to Goldblatt syndrome, also known as odontochondrodysplasia. AIM: We report the analysis performed on a female young patient affected by this disease. We analyzed her dental and or facial features. MATERIALS AND METHODS: We adopted several diagnostic criteria: firstly, we performed radiographic investigations, followed by rhinomanometric measurements and by clinical analysis performed in order to determine the salivary flow in this typology of patients. The evidences obtained after a careful clinical, anamnestic, and radiographic analysis of our female patient allowed us to identify a number of odontostomatologic features, which are very likely to be related to this syndrome. Our patient showed some pathognomonic signs of odontochondrodysplasia already identified in the literature, that is, pectus carinatum, joint hyperextensibility, coxa valga and genu valgum, upper and lower limb asymmetry, and vertebral abnormalities. Moreover, we focused our attention on those odontostomatologic aspects that had never been analyzed by other reports in the literature: dentinogenesis imperfecta, ligamentous hyperlaxity of all joints and of temporomandibular joints in particular, poor lip competence, ogival palate, and oral respiration. Besides these, dental crowding and other important elements were identified through cephalometric measurements. DISCUSSION AND CONCLUSIONS: In the light of all these elements and of their comparison with the existing literature, it is possible to stereotype a few recurrent odontostomatologic and systemic-generalized features in patients with odontochondrodysplasia, which can be considered as closely associated with this syndrome.

Use of dermal-fat grafts in the post-oncological reconstructive surgery of atrophies in the zygomatic region: clinical evaluations in the patients undergone to previous radiation therapy.

INTRODUCTION: Grafting of autologous adipose tissue can be recommended in some cases of facial plastic surgery. Rhabdomyosarcoma is a type of cancer that can also affect the orbit. Enucleation of the eye can cause atrophy of the corresponding hemiface and decreased orbital growth. CASE REPORT: We report a case of a female patient with a medical history of surgical enucleation of the right eyeball, who had received rhabdomyosarcoma radiation therapy in her youth. The patient presented with a depression in the right zygomatic region. We took a dermal-fat flap from the abdominal region, which had been previously treated. RESULTS: The surgical outcome, 48 hours, and much clearly 31 days after the surgery, revealed that the right zygomatic region had returned to its proper anatomical shape, although there were still signs of postoperative edema. DISCUSSION: Very damaged tissues, like those exposed to radiation therapy, are generally not suitable for grafting of adipose tissue. CONCLUSIONS: In the described case, we achieved a technically and aesthetically satisfying result despite the patient's medical history involving several perplexities about the use of autologous dermal-fat tissues, because of prior radiation therapy exposure. The clinical case shows that even a region exposed to radiation therapy can be a valid receiving bed for dermal-fat grafting.