No abstract

Fractures of polymer material are one of the most frequent reasons for the repair of removable dental prostheses. Therefore, there is a constant endeavor to strengthen them, and polymer materials with high resistance to fracture are being developed. The aim of this study was to determine the flexural strength of polymer materials and their reinforcements and thus give preference to their clinical use. Specimens with dimensions 18 x 10 x 3 mm were tested after polymerization, immersion in water at a temperature 37 degrees C for 28 days, and thermocycling by using the "short-beam" method to determine the flexural strength. Microscopic examination was performed to determine the quality of bonding between the glass fibers and matrix. Common polymer materials (control group) demonstrated the lowest flexural strength, although, when reinforced with fibers they showed higher flexural strength, matching that of the tested high-impact strength resin. Thermocycled specimens had the highest flexural strength, whereas there was no difference (p > 0.05) between specimens tested after polymerization and immersion in water.

Adresa za dopisivanje doc. dr. sc. Predrag Knežević Sveučilište u Zagrebu Stomatološki fakultet Klinika za kirurgiju lica, čeljusti i usta Klinička bolnica Dubrava,

Aplastic anemia is a hematological disorder characterized by pancytopenia. This case report presents a young patient with untreated periodontitis associated with hematological disorders, and cyclosporine therapy. During 2 consecutive days, periodontal therapy which consisted of nonsurgical therapy supplemented with an antibiotic treatment and antifibrinolytic therapy was performed. Commercial microbiological PCR tests and periodontitis IL-1 polymorphism risk test were performed. Following the periodontal therapy, the inflammation was resolved and the patient's occlusion was restored by means of removable partial dentures. After the 5 year follow-up, the patient still remained with shallow probing depths although there was inadequate compliance during the maintenance phase. Aplastic anemia increases the risk of onset of severe forms of periodontitis that can be additionally complicated with cyclosporine therapy. In such patients, periodontal therapy must be supplemented with antibiotics.

A new bonding system named Kevloc has been introduced. It is based on acrylization of the metal surface with the goal of preventing the occurrence of a marginal gap between the metal and the resin. The purpose of this investigation was to determine the values of the shear bond strength achieved using the Kevloc technique on Ag-Pd (Auropal SE) and Co-Cr (Basil S) alloys and to compare them with those obtained with the OVS technique. The shear bond strengths were measured with the Smitz-Schulmayer shear test in a universal testing machine for polymer materials. A microscope image analyzer was used to measure the thickness of bonding layers and to reveal the possible occurrence of the marginal gap with both techniques. No marginal gap was detected with either technique. Kevloc provided better results than OVS only in a group of specimens tested after polymerization. Immersion in water and thermocycling reduced the initially high bond strength values of Kevloc specimens, whereas the bond strength values of OVS specimens remained unchanged regardless of which aging treatment was used. Microscopic examination did not reveal the existence of the marginal gap for either bonding system. According to the results obtained, it can be concluded that the Kevloc bonding system does not provide better shearing bond strength than the OVS bonding system.

Background : Maxillary alveolar ridge resorption with a consequential width reduction and limitation of drilling into an atrophic ridge present a frequent problem in implantology. In such cases bone expansion and bone condensation, prior to dental implant placement, make additional surgical augmentation unnecessary especially in patients who refuse augmentation. D-shaped bone expanders, with an increasing diameter, push the alveolar cortical bone laterally by separating the labial and palatal lamellae.Aim/Hypothesis : To show advantages and disadvantages of bone expansion and condensation in gaining the horizontal dimension of the maxillary alveolar ridge on four patients. The purpose was to show how the bone condensers, due to the rounded profile, after bone expansion, adjust the bed for implant placement.Material and Methods : Dental implant bed was prepared in all patients using bone expanders and bone condensers. Case 1-a year after tooth 24 was extracted, alveolar width and height was 3 and 17 mm. Case 2-teeth 24 and 25 were extracted after several apicoectomies. The gap between implants and between implants and bone was filled with a particulated xenograft. Case 3-socket preservation was performed after the extraction of a fausse-routed tooth 22. During the healing period, a temporary Maryland bridge was provided. Case 4-the bilateral sinuslift was performed and bone-grafts placed due to insufficient alveolar width. Six months later, bone showed low resistance during pilot drilling.During the implant bed preparation the graft had detached. Nevertheless, six implants were inserted and bone graft was fixed by screws. In all patients Ankylos implants (Dentsply Sirona, Germany) were inserted, and resorbable membranes and particulated xenograft were used (Bio-Gide® and Bio-Oss®, Geistlich, Switzerland Results : In all patients a poorly structured bone showed low resistance during pilot drilling. All the implants were inserted six months after teeth extractions and implant beds were prepared using bone expanders and bone condensers. All implants were loaded six months after insertion. After a five-year follow-up period, satisfactory functionality and esthetics were observed in all four cases. Conclusion and Clinical Implications: Bone expansion and condensation are valuable alternative techniques for implant insertion into maxillary alveolar ridge with compromised width. Poorly structured bone shows low resistance during pilot drilling. Thereby, instead of drilling, bone expanders can provide adequate bone width allowing that the implant bed is created by condensation. Both procedures can ensure bone dimensions to the adequate diameter of the planned implant. The healing phase should last up to six months (after these procedures).