Mário Vasconcelos

Granules of osteopatite and glass-reinforced hydroxyapatite implanted in rabbit tibiae

Granules of a modified hydroxyapatite, glass-reinforced hydroxyapatite composite and commercial hydroxyapatite were implanted in rabbit tibiae. Histological studies were carried out after 1 and 2 months implantation periods using light and fluorescence microscopy. A much higher percentage of bone contact was developed for both the glass-reinforced hydroxyapatite composite and the modified hydroxyapatite when compared to commercial hydroxyapatite (89–91% versus 66%) after 2 months implantation. The mechanism of bone formation and growth around implants is discussed in terms of the influence of elements incorporated into these novel materials which are commonly found in bone tissues, such as Na, K and Mg, and the presence of a soluble β-tricalcium phosphate phase in the microstructure of the composite.

An in vitro and in vivo investigation of the biological behavior of a ferrimagnetic cement for highly focalized thermotherapy

The cancer treatment by local hyperthermia, using a high frequency electromagnetic field is an extensively studied subject. For this propose it was developed a ferrimagnetic cement (FC) to be injected directly into the tumor. In this study it was determined the FC injectability, its capability to generate heat when placed within a magnetic field and its interaction with a modified simulated body fluid using SEM/EDS and XRD. The FC biological response was assessed by the intramuscular implantation in rats and histological analysis of the surrounding tissues. The results suggest that FC can be injected directly into the tumor, its temperature can be increased when exposed to a magnetic field and the surface of the immersed samples quickly becomes coated with precipitate denoting its ionic change with the surrounding medium. The histological analysis revealed a transient local inflammatory reaction, similar to the control material, only slightly more abundant during the first weeks, with a gradual decrease over the implantation time. Based on these results, we concluded that FC might be useful for highly focalized thermotherapy, with a good potential for clinical use.

Highly focalised thermotherapy using a ferrimagnetic cement in the treatment of a melanoma mouse model by low temperature hyperthermia

Purpose: Evaluation of the effectiveness of highly focalised thermotherapy (HFT) in a melanoma mouse model, using a ferrimagnetic cement (FC) and repeated low hyperthermia treatments. Materials and methods: A melanoma mouse model was induced with B16F10 cells in C57BL6 mice. The FC, injected into the tumour, was used as the magnetic vehicle for HFT. FC location within the tumour was assessed by radiography and its capability to generate heat, when exposed to an external high frequency magnetic field (HFMF), monitored by thermal camera. The HFT treatment consisted of three HFMF exposures, with 48-h intervals, each one lasting 30 min, with a 5–6°C tumour temperature increase. At the end of the experiment, FC samples were characterised by scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS). The presence of iron contents was analysed in the tumour, lungs, liver and spleen. Histological evaluation and immunohistochemical staining for caspase-3 were performed. Tumour growth was monitored during the experiment. Results: Surface analysis showed FC stabilisation within the tumour, and iron was absent. The thermal camera confirmed the localised temperature increase in the tumour. HFT treatments inhibited the tumour growth by ∼70% compared to controls. This was due to cell destruction by necrosis and apoptosis. Conclusions: The HFT, using the FC, proved to be a minimally invasive technique that statistically inhibited tumour growth. Results suggested that this methodology seems to be a promising technique for the treatment of solid tumours, allowing repeated low hyperthermia treatments, which can be easier and less traumatic than other hyperthermia techniques.

GUIDED BONE REGENERATION USING OSTEOPATITE GRANULES AND POLYTETRAFLUOROETHYLENE MEMBRANES

Granules of a modified hydroxyapatite, Osteopatite®, were implanted in the right posterior tibiae of adult rabbits. We studied the extent of bone regeneration in bone holes. In the right tibiae, that were filled with granules of this biomaterial covered with a polytetrafluoro-ethylene (PTFE) membrane using, as a control, uncovered granules. In the left tibia, an empty hole was covered with PTFE membrane and a second hole was left empty to be used as a control. A histomorphometric study was carried out using light microscopy, four and eight weeks after the surgery. The covered granules presented a higher percentage of bone contact than the uncovered ones, and it was also possible to observe a better bone tissue organization, mainly produced by the immobilization action of the PTFE membrane. Empty bone defects covered with PTFE membranes, two months after implantation, presented large areas of Haversian bone and direct bone contact to the PTFE membrane.

Glass Reinforced Hydroxyapatite Composites: Physical Properties and Preliminary Histological Studies in Rabbits

ABSTRACT Glass reinforced hydroxyapatite composites were fabricated by a liquid phase sintering process. These composites showed to have much higher fracture toughness than sintered hydroxyapatite, 1.2 compared to 0.5 MPa m1/2. “In vitro” tests in simulated physiological solution indicated potential bioactive behaviour, with formation of an apatite layer after 1 week immersion. Preliminary “in vivo” studies in rabbits showed a very close contact between bone and implanted materials.

Dental stem cells Characterization and Bone Regenerative Potential in oral Medicine

C l i n M e d International Library Citation: Rodrigues R, Viana B, Vieira I, Tavares J, Lobo R, et al. (2015) Dental Stem Cells Characterization and Bone Regenerative Potential in Oral Medicine. Int J Stem Cell Res Ther 2:009 Received: April 30, 2015: Accepted: May 31, 2015: Published: June 02, 2015 Copyright:

Modified Hydroxyapatite Granules and Plaster as Binder: In Vitro and Clinical Tests

ABSTRACT Hydroxyapatite (HA), produced by chemical precipitation is normally used as a bone graft. Hydroxyapatite modified (HAM), allows the fabrication of granules of a different material with HA structure. The aqueous medium that involves HAM particles has higher pH than the particles of HA, improving the conditions of formation of new bone. In this work the chemical and physical properties of this new HAM granules were studied. A clinical test in dental alveolus in 10 patients, using plaster as binder was carried out. Microradiographic results and histological cuts, retrieved from experimental surgery in dogs, showed the useful behaviour of the association HAM/plaster.

The effect of a biphasic calcium phosphate on bone healing: a pilot study in rats.

PURPOSE The primary objective of this pilot study was to evaluate the effectiveness of biphasic calcium phosphate (BCP) covered with a polyethylene glycol (PEG) membrane in the regeneration of 5-mm-diameter defects created in the calvaria of Wistar rats and compare this with the regeneration of defects covered only with the PEG membrane. MATERIALS AND METHODS Two 5-mm-diameter parietal defects were created in seven Wistar rats. The control defect in the left parietal bone was covered with an experimental PEG membrane (Straumann MembraGel); the test defect in the right parietal bone was filled with BCP (Straumann BoneCeramic) and covered with the same membrane. After a healing period of 2 months, the animals were sacrificed, and the samples were processed for histologic and histomorphometric analysis. RESULTS The test defects regenerated with BCP and covered with the PEG membrane had a percentage of new bone formation area of 61.7% ± 14.6%, and the control defects obtained mean new bone area of 57.3% ± 21.8%. The difference between groups was not statistically significant. The BCP did not reveal osteoconductive properties, and few particles were fully incorporated into the newly formed bone. The BCP maintained the space, and there was extremely low particle resorption during the healing period. The PEG membrane remained intact. CONCLUSION There were no statistically significant differences between the test and control groups. BCP did not exhibit osteoconductive properties.

Thermographic Evaluation of the Saxophonists’ Embouchure

The orofacial complex is the primarily link between the instrument and the instrumentalist when performing the musician’s embouchure. The contact point is established between the saxophonist lower lip, the upper maxillary dentition and the mouthpiece. The functional demands of the saxophone player and consequent application of forces with an excessive pressure can significantly influence the orofacial structures. A thermographic evaluation was performed to an anatomical zone vital for the embouchure, such as the lip of the saxophonist. Substantial temperature changes occurred before and after playing saxophone. The specificity of the embouchure regarding the position of the lower lip inside the oral cavity, the anatomy and position of the central lower incisors can be some of the factors involved in the origin of the existing temperature differences on the thermographic evaluation.

Adhesive systems: antimicrobial agents

Nowadays a trend to shift toward metal-free restorations has been observed in the dental field because from a purely cosmetic standpoint, the value of the appearance of one’s teeth has taken on a greater importance in today’s society therefore, all ceramic restoration has became the mainstay of aesthetic dentistry in the last few years offering superior aesthetics combined with high bio-compatibility, ever increasing strength and long-lasting restorations. Therefore several types of all ceramic systems have been developed [1-4]. Among them, In-Ceram Zirconia (VITA Zahnfabrik) which developed as a modification of the original In-Ceram Alumina system, with an addition of 35% partially stabilized zirconia oxide to the slip composition to strengthen the ceramic [5]. The available fixed dental prosthesis (FDP) treatment options for missing anterior tooth include implant supported crown, traditional and resin-bonded teeth supported FDP. Every treatment modality offers some advantages and disadvantages but still the golden role for the dentist and patient is that, whenever possible conservation of tooth structure is a goal during teeth preparation.Background: Despite the growing tendency toward tooth-colored restorations in dentistry, polymerization shrinkage and subsequent marginal microleakage remains a problem. The aim of this in vitro study was to compare microleakage between silorane-based and methacrylate-based composite resins at different time intervals and with different restorative techniques. Materials and Methods: In this in vitro study, 108 sound extracted human molar teeth were used. Mesial and distal proximal class II boxes with dimensions of 1.5 mm depth and 4 mm width were prepared. The gingival margins of all cavities were 1 mm below the cement enamel junction. The teeth were randomly divided into three groups based on test materials. In the first group, the teeth were restored by a nanocomposite (Filtek Z350XT, 3MESPE) and SE Bond adhesive (Kuraray, Japan), in the second group, the teeth were restored with a silorane-based (Filtek P90, 3MESPE) and Filtek P90 Adhesive (3M ESPE, USA) and in the third group, the teeth were restored with a microhybrid posterior composite resin (Filtek P60, 3MESPE) and SE Bond adhesive (Kuraray, Japan). Half of the proximal cavities in each of these three groups were restored in two horizontal layers and the other half in four horizontal layers. After a period of aging (24-h, 3-month and 6-month) in water and then application of 500 thermal cycles, the teeth were immersed for 24-h in 0.5% fuchsin and evaluated under a stereomicroscope at ×36 magnification to evaluate leakage in gingival margin. Data was statistically analyzed using Kruskal-Wallis and Mann-Whitney U-tests. P ≤ 0.05 was considered as significant. Results: In Z350XT statistically significant differences were observed in microleakage in comparison of 24-h and 6-month intervals (P = 0.01) that was higher in 6-month. Comparison of microleakage in P90 and P60 composite resins was also statistically significant and was less in P90. Microleakage was not significantly different between P90 and Z350XT at 24-h. However, this difference was significant at 3-month and 6-month intervals. Differences in microleakage of P60 and Z-350XT composite resins were not statistically significant in all intervals (P = 0.38). P90 showed the lowest microleakage during storage in water. Z350XT had microleakage similar to P90 within 24-h, but after 6-month of storage in water, it showed the highest microleakage among all the groups. The number of layers (2 layers vs. 4 layers) did not result in any differences in microleakage scores of the composite resins (P = 0.42). Conclusion: Water storage times did not result in any significant effect on microleakage of P90 and P60.A dental procedure should always combine aesthetics, function (chewing, swallowing), neuromuscular balance and phonetics. Besides the tongue, anterior teeth help with production of friction in some sounds like [s] and [z]. The most influenced sound by the positioning of anterior teeth is [s]. This is the sound that undergoes more changes and it is more difficult to reproduce in patients with any type of oral rehabilitation involving the anterior sector (upper and lower).R infiltration is a novel technology providing an intermediary treatment option between prevention and restorative therapy. The concept was introduced as a micro-invasive approach for the management of smooth surface and proximal non-cavitated caries lesions. It also holds great potential in the management of non-caries demineralization problems.The purpose of this lecture is to present the scientific basis and principles of the usage of resin infiltration technique and relate the available knowledge to clinical practice. The lecture will also include presentation of clinical cases in which resin infiltration technique was used in the management.A veneers became an interesting treatment option for the patient offering high esthetic profile with minimal tooth reduction. However, these thin shells are very challenging and require meticulous clinical management and careful laboratory handling in order to produce the required shade and appearance. All-ceramic veneers are required to mask the shade of underlying teeth, provide vital of translucency, resist forces of mastication, and compensate for malpositioningoffront teeth.• failure to diagnose the need for endodontic treatment, including failure to evaluate radiographically and failure to per form appropriate tests; • failure to refer to an endodontist for treatment, either initially or after difficulties were encountered; • incorrect performance of the procedure, including failure to treat all canals, obturation that is unacceptably long, short or poorly condensed, and perforations of the root or pulp chamber; • failure to take reasonable precautions (usually failure to use a rubber dam); and • failure to inform the patient of a separated instrument left in the canal Quick recognition and good judgment can reduce the chance of a malpractice claim arising from an endodontic complication. Be objective about your ability to manage these complications and keep your patient’s best interests in mind.The decrease in bond strength of adhesive interface occurs due to degradation of the hybrid layer. The chlorhexidine is a stable antibacterial molecule and a potent inhibitor of MMPs. DMAE-CB is, as MDPB, a monomer with antibacterial properties. This article review aims to evaluate the antimicrobial capacity of adhesive systems. Chlorhexidine is able to inhibit bacterial activity in dental treatments without interfering in the mechanical properties of the interface dentin/adhesive. The monomers MDPB and DMAE-CB have an important role in the antimicrobial ability of adhesive systems because it maintains this property after polymerization. Apart from its antimicrobial activity, all incorporated agents chlorhexidine, MDPB and DMEA-CB, have shown ability to inhibit MMPs.I prostheses have become the treatment of choice in an increasing number of patients, however, this model of treatment remains controversial under which conditions retaining a tooth may be futile and replacing a tooth with an implant-supported prosthesis may be considered over-treatment.Decision making is an essential part of oral health care. A model for the factors influencing decision in healthcare was described in 2000 by Chapman and Sonnenberg and has been adapted to discuss decision making in implant dentistry. This model describes two major components, the normative and the descriptiveapproach, which are involved in decision making. The normative aspect relies on quantitative information derived from systematic reviews and predictive models on the probabilities of treatment outcomes. The descriptive aspect in decision making involves cognitive processes and biases of both providers and patients that translate the normative information into clinical action.In implant dentistry, the evidence based and decision analysis constitutes two major approaches in treatment planning. Recently, a number of systematic reviews have been published regarding the success and survival rates of teeth following periodontal and endodontic treatments and of dental prostheses supported by teeth or implants. This review does not intend to replicate these systematic reviews; instead this presentation will focus on building upon the complied information, synthesize the provided data and apply them in a clinical context to establish the decision making process at the provider-patient level to assess which may offer greater benefits, namely treating diseased teeth with the goal of retaining them or extracting diseased teeth and replacing them with an implant-supported fixed dental prostheses.T explosive development of new technology in endodontic therapy, as well as innovative solutions to unanswered questions of the past in the field of Endodontics, will continue at an exponential rate well into this millennium. Although the latest tools for performing endodontics, such as rotary instrumentation and thermoplastic obturation techniques, have elevated the specialty to a level of sophistication never before attained, a number of areas remain that require significant advancement. Diagnosis is one of the areas of main concern. While medicine has catapulted itself in the areas of prevention and diagnosis, endodontics is lagging behind in these areas. Pulpal diagnosis may no longer be strictly based upon ice application or tapping a tooth with the end of a mirror handle but we still continue to use this as the main tool. Scenarios such as these are not too far off in the distant future and that’s why Supporters of Dental Implants keep on threating the unconquered regime of Endodontics.