Stereomicroscopic Aspects of Non-Carious Cervical Lesions.

Non-carious cervical lesions (NCCLs) represent a form of tooth wear, characterized by the irreversible loss of dental hard tissues at the enamel-cement junction, without the involvement of caries and dental trauma. The aim of this study was to highlight the morphological elements of NCCLs via their stereomicroscopic examination and to confirm the role of this examination in the diagnosis of early lesions. In addition, the association between the morphological aspects identified during the stereomicroscopic examination of NCCLs and their etiological factors was determined. For this study, extracted teeth with NCCLs were examined with a stereomicroscope. The morphological aspects of NCCLs were evaluated at magnifications up to 75×. In wedge-shaped NCCLs, the stereomicroscopic examination allowed the identification and measurement of scratches, furrows and cracks. In saucer-shaped NCCLs, the stereomicroscopic examination highlighted the smooth appearance of the walls. The presented study highlighted the role of stereomicroscopic examination in the assessment of NCCL morphology and in their early diagnosis. The study confirmed, in particular, the role of occlusal overloads and tooth brushing in determining the morphology of NCCLs.

Osseointegration evaluation of an experimental bone graft material based on hydroxyapatite, reinforced with titanium-based particles.

Bone graft materials are more and more frequently used in dentistry for improving the periodontal support and for creating a bone support favorable for the insertion of dental implants. The experimental study carried out on laboratory animals aimed to evaluate the biocompatibility and the manner of integration of an experimental bone augmentation material, based on hydroxyapatite (HAp), reinforced with titanium-based particles by comparison with a commercial synthetic graft material already existing on the profile market, also based on HAp. We noticed a common pattern of evolution, although there were differences related to the speed of new bone tissue formation and implicitly the morphological elements captured at the two moments of time. In the presence of both synthetic materials, ossification also begins from the center of the cavity at distance from the margins of the bone defect, with a common pattern with an appearance with the presence of osteon-like structures. The experimental material generally determined a more intense initial inflammatory reaction, followed by the generation of a repair bone tissue with a denser appearance but with a less uniform structure and a greater number of residual particles.

Calcium fructoborate coating of titanium-hydroxyapatite implants by chemisorption deposition improves implant osseointegration in the femur of New Zealand White rabbit experimental model.

BACKGROUND: The identification of biocomposites that improve cell adhesion and reduce bone integration time is a great challenge for implantology and bone reconstruction. AIM: Our aim was to evaluate a new method of chemisorption deposition (CD) for improving the biointegration of hydroxyapatite-coated titanium (HApTi) implants. CD method was used to prepare a calcium fructoborate (CaFb) coating on a HApTi (HApTiCaFb) implant followed by evaluation of histological features related to bone healing at the interface of a bioceramic material in an animal model. METHODS: The coating composition was investigated by high-performance thin-layer chromatography/mass spectrometry. The surface morphology of the coating was studied by scanning electron microscopy (SEM), before and after the in vitro study. We implanted two types of bioceramic cylinders, HApTi and HApTiCaFb, in the femur of 10 New Zealand White (NZW) rabbits. RESULTS: The release of CaFb from HApTiCaFb occurred rapidly within the first three days after phosphate-buffered saline immersion; there was then a linear release for up to 14 days. SEM analysis showed similar morphology and particle size diameter for both implants. Around the porous HApTiCaFb implant, fibrosis and inflammation were not highlighted. CONCLUSIONS: Easily applied using CD method, CaFb coatings promote HApTi implant osseointegration in the femur of NZW rabbits.

A microscopic insight of the morphological changes induced by dental zirconia prosthetic structures.

As zirconia is today probably the dental material with the largest increase in the frequency of use in dental prosthetics, the reason for this study was based on a series of clinical observations made following its use in clinical prosthetics. Thus, we were interested in two aspects: the histological evaluation of the response of the oral soft tissues to the presence of the prosthetic structures in zirconia, and the microscopic evaluation of the abrasion lesions that appeared in the hard dental tissues of the zirconia prostheses antagonists. For the first part, samples from three zirconia-based dental prosthetics commercial products were implanted submucosal in the oral cavity of male Wistar rats. After six weeks, the oral soft tissue reaction was clinically and then histologically investigated. For the second part, we made two study groups to investigate the influence of the zirconia-glazed surface vs. polished surface to the wear pattern of the antagonist enamel, using a tribological equipment and a dedicated software. Our study showed a good clinical response of the oral soft tissues surrounding the inserted zirconia samples, with subclinical, only histological revealed, signs of inflammation, of a foreign body reaction, while polished zirconia samples determined abrasion surfaces, with a different pattern and significantly smaller dimensions, compared to zirconia glazed samples, at the level of the hard dental tissues of the antagonist teeth. Despite the generally good response of the biological structures to the presence of zirconia prosthetic structures in the oral environment, more scientifically proved information is needed to obtain the desired biological responses in all clinical situations.

A correlation between thermodynamic properties, thermal expansion and electrical resistivity of Ag-28% Cu nanopowders processed by the mechanical alloying route.

Thermodynamic properties, thermal expansion and electrical resistivity of the Ag-28% Cu nanopowders processed by the mechanical alloying route have been investigated in the temperature range from ambient to 1048 K. The thermodynamic properties represented by the relative enthalpy, the specific heat capacity, the relative entropy and the Gibbs energy function obtained from drop calorimetric measurements have been used to reveal the occurrence of the micro-relaxation process, as well as of the correlative effects of decomposition and growth processes. On the basis of the results, the parameters that favour stable nanostructured systems in Ag-28% Cu powders synthesized by the mechanical alloying route have been identified. The correlation of the energetic parameters with thermal expansion and electrical resistivity in mechanical alloyed nanocrystalline powders with the eutectic composition is discussed.