Cristian Ratiu

Titania versus Ceria Alumina/Zirconia Composites: Structural Aspects and Biological Tolerance

The aim of our study is to compare the structural and biological tolerance of novel Al2O3/3Y-TZP composites with ceria respectively titania addition (5 wt%). Scanning electron microscopy, X-ray diffraction, infrared spectroscopy and XPS results are reported for structural characteristics and surface modifications upon different fluoride treatments. The biocompatibility of the samples was evaluated using an animal model (rabbit). The explants were analyzed at a specific period (6 weeks).The sections of implanted bone area were subjected to histological evaluation. Upon correlating the structural properties and in vivo evaluation, we concluded that the addition of both TiO2 and CeO2 to Al2O3/3Y-TZP implies similar properties and satisfactory biological tolerance. With respect to the surface treatment, qualitative and quantitative results show that the alumina/zirconia with titania addition are more sensitive to fluoride treatment.

Correlation between Structural Properties and In Vivo Biocompatibility of Alumina/Zirconia Bioceramics

The aim of our study is the characterization and comparison of structural properties of two novel alumina/zirconia ceramics prepared by Spark Plasma Sintering and biocompatibility evaluation by using an animal model (Wistar rats). SEM, XRD and FTIR spectroscopic results are reported for structural characteristics. In vivo tests demonstrated the biocompatibility and osseointegration of the composites by complementary SEM and histological analysis of the defects in rat femur respectively the connective tissue.

The Assessment of Acrylic Infantile Overdenture during the Treatment of Anodontia in Children: A Case Study

Anodontia or dental agenesis in children is difficult to treat, as the child is smaller. The treatment of anodontia is a complex one, it is important to mention that the children’s body is upgrowing and, also, the psychological implications that could appear in children without teeth. The materials used in acrylic infantile overdenture must be non-toxic and shouldn’t have any negative influence in upgrowing children. The base of acrylic infantile overdenture is made of acrylic resin. The aim of the present study is to highlight the changing of regular acrylic infantile overdenture, at the age of 1 and a half, in order to allow the physiological growth of the children’s bones.

The Assessment of Ceramic Dental Materials during the Treatment of Severe Adult Cleft Palate: A Case Study

The materials used in the treatment of an adult patient with severe cleft palate need to be choose very carefull, according with the biological aspects. First of all, is mandatory to choose a proper material for endodontic treatment and use a correct technique. Second, the cement used in order to fix a RPD (rapid palatinal disjunctor) has to be glass-ionomer cement, because the oral and nasal cavity are still communicating. On the other hand, the dental ceramic material used in the prosthetic treatment has to be a special one, pink-colored in those regions where cleavage is present. For this reason, the cases with cleavage need a complex treatment, usually during a few years and several steps. They need a good collaboration between doctors of different specialities: maxillo-facial surgery, orthodontics, prosthetics and plastic surgery. The aim of the present study is to underline the assessment of ceramic dental materials during the laborious treatment in the case of an adult with cleft palate, in order to obtain the best results.

Immediate Loading of Dental Implants - A Case Study

The ability to achieve predictable results in oral implantology depends on indepth knowledge of all factors affecting bone healing, as well as on implant characteristics and the mechanical forces involved in immediate loading. The success of the immediate loading protocol relies on three main factors: (1) primary stability, which limits micromotion of the implant, (2) secondary biologic stability, resulting in osteogenesis in the peri-implant area, and (3) the control of bone resorption caused by deleterious loading forces that lead to implant instability during healing. Activated platelets play a crucial role in peri-implant healing and the use of Plasma Rich in Growth Factors (PRGF) in association with immediate implant placement could be a viable therapeutic option for the reabilitation of postextraction sockets. In our case-study, the implants and the abutments were welded with a titanium bar in order to provide predictable fixation and immobility of implants in early stages of bone healing. The implants have been properly integrated at both the bone and gingiva levels allowing the patient to resume both esthetic and masticatory functions from the very day the implants are inserted.

Zirconia Neck Implants vs Bone Augmentation

Different graft materials and techniques are suggested based on the number of bony walls that remain after the tooth is removed. If the implant can’t be inserted within the bone contours, bone augmentation must be performed, and the graft must be stabilized with a membrane or a thin bone block graft. In the present study, two cases are presented both with small bone defects on the buccal plate. Bone augmentation with autogenous bone graft was performed in one case, respectively titanium implants with zirconia necks were used in the second case. It was demonstrated that titanium implants with zirconia necks are a good choice in some cases where small parts of the buccal plate are missing.

STRUCTURAL PARTICULARITIES OF THE EPITHELIUM LINING THE LAMB EPIGLOTTIS

Epiglottis presents a central axis covered by mucosa. The aim of this study was highlighting the type of epithelium lining the lamb epiglottis. Thus, we histologically processed the epiglottis from 3 lambs. The epithelium lining the whole epiglottis surface is non-keratinized stratified squamous, with different thickness from one side to the other. Hence, on the pharyngeal side the epithelium is twice as thick as the one found on the laryngeal side.

Alternative Approaches Using Animal Model for Implant Biomaterials: Advantages and Disadvantages

This study presents some aspects regarding the evaluation of bone-implant interactions using two animal models (rabbit and rat). The proposed implants are new alumina/zirconia bioceramics designed for hard tissue replacement (oral implantology or arthroplasty). The animal selection was made based on the number and size or design of implants to be tested as these factors influence directly the species of animal chosen for this study. The correct placement and stability of the implants were evaluated by radiographic images. SEM micrographs were recorded on the bone/implant area along with the elemental composition of the sheared implant surfaces at different time intervals after the surgery. Calcium/phosphate ratio was considered as an indicative of the surface implant coverage for a successful osseointegration. Histological examination of the bone and bone marrow in direct contact with the implants was performed to detect any immunological or inflammatory responses. Each of the animal species (rat or rabbit) demonstrated unique advantages and disadvantages as a model for demonstrating the response of bone tissue to an implant material. The size and design of the implants also influenced the bone turnover as demonstrated histologically.

Autologous Bone vs. Allograft Bone in Ridge Augmentation

Most of edentulous areas need reconstructive procedures of hard tissues for an ideal implant position. In this perspective, guided bone regeneration with semi-permeable membranes or onlay bone grafts harvested from intra-or extra-oral sites is indicated. Establishment of well regulated tissue banks allows surgeons use of allograft bone. This study compares two clinical cases, where a relevant horizontal deficit was present: first one reconstructed with allograft bone + titanium mesh and the other one with onlay graft + autogenous cortico-spongiosa bone particles, harvested from ramus. In both cases plasma rich in growth factors and fibrin membranes were used in order to enhance graft vascularization and osseous regeneration, as well as faster healing.

Grafting Materials for Major Sinus Lift

The materials used for major sinus lift varies from autogenous or allogenous bone, to animal origin (xenograft) bone or synthetic (alloplastic) materials. A combination of bone substitutes, alloplastic graft with allogenic or xenogenic bone seems to give satisfactory results in terms of new bone formation and the long-term implant success rate. On the other hand, using PRP (Platelet Rich Plasma) mixed with bone substitutes seems to enhance graft vascularization and osseous regeneration, as well as faster healing. The novel sinus lift technique with PRGF (Plasma rich in Growth Factors) has demonstrated significant development of new bone, minimizing any complications in the event of Scheneiderian membrane perforation. The present study compares two clinical cases where major sinus lifts were performed using as regenerative material xenograft bone and porous titanium mixed with PRGF.