Search

Purpose: Implant geometry has a major impact on insertion torque values and primary stability, and bone engagement during implant insertion differs according to implant morphology. Primary stability of straight-walled and tapered implants was compared using insertion torque monitoring. Materials and Methods: A total of 57 implants (36 straight-walled OSSEOTITE and 21 tapered OSSEOTITE NT) were inserted in 20 patients. Implant torque values and insertion times were recorded, and the data were processed and interpolated to determine torque as a function of time. Results: Tapered implants required less insertion time and a higher insertion torque than straight-walled implants; this provided better primary stability, although the success rate was 86% for tapered and 100% for straight-walled implants. Conclusions: Tapered implants showed better primary stability than straight-walled implants but had a lower success rate. The authors suggest that in low-density bone, in which only a thin dense cortical layer can contribute to primary stability, a higher insertion torque can lead to the destruction of peri-implant bone, compromising osseointegration. [ABSTRACT FROM AUTHOR]

This study aimed to (1) devise a standardized method of polishing and finishing acrylic resins, (2) eliminate the variable linked to the single operator, and (3) guarantee the reproducibility of the conditions in which smoothness surface values are obtained for comparative purposes. Twenty acrylic resin samples were fabricated (Lucitone, Dentsply). Samples in group 1 were manually polished by a single experienced operator, while samples in group 2 were polished using an isoparallelometer. Surface roughness was measured for both groups with a +/- 0.01-microm resolution profilometer (Mahr, GD25). Data analysis showed that mechanical polishing results in a more uniform surface quality. This preliminary investigation underscores the merits of a standardized method for polishing dental acrylic resins. This approach can eliminate the effect of human factors, thereby making it possible to assess and compare the inherent features of each polished dental material. [ABSTRACT FROM AUTHOR]

PURPOSE: Obstructive sleep apnea syndrome (OSAS) is a sleep disorder characterized by repetitive episodes of upper airway obstruction. Recently, it has been suggested that edentulism worsens sleep apnea; sleeping without dentures is associated with a significant increase in the apnea-hypopnea index. OSAS is also related to depression. The aim of this study was to assess, in a group of elderly occupants in residential homes in the Turin district of Italy, (1) the prevalence of key symptoms and indicators of OSAS and the prevalence of depressive feelings; (2) how the reduction of vertical dimension of occlusion (VDO) influenced the onset of OSAS; and (3) whether a relationship between OSAS and depression was present. MATERIALS AND METHODS: The sample population consisted of 403 people (77% men, 23% women; age range, 65 to 90 years). The subjects underwent the Italian version of the Mini Mental State Examination (MMSE) to assess their mental condition. The remaining collaborating subjects completed 2 questionnaires to assess the risk of OSAS (Berlin Questionnaire) and depressive feelings (Beck Depression Inventory). RESULTS: Of the 403 elderly residents initially evaluated with the MMSE, 97 were excluded from the study, reducing the sample size to 306 subjects (75% women, 25% men; mean age +/- standard deviation, 83.12 +/- 11.10 years).The analysis of these data revealed a statistically significant association between the risk for sleep apnea and the VDO (P < .0001), and between sleep apnea and depressive feelings (P < .05). CONCLUSION: This study revealed that inadequate VDO is closely associated with the risk of OSAS, and that depressive feelings are more present if there is a high risk for OSAS. [ABSTRACT FROM AUTHOR]

Silicon nitride (SiN) has been introduced clinically as an orthopedic biomaterial for interbody fusion devices and in joint replacements. However, the production of complex shapes through conventional mechanical machining is difficult and expensive and limits interesting applications. Thus, several electrically conductive reinforcements to the SiN matrix, like TiN, have been proposed, generating composites suitable to be wrought by electrical discharge machining (EDM). In this study, SiN-TiN with high strength, low density, and good electric conductivity wrought by EDM was studied. The role of surface finishing was investigated comparing the interface generated during the EDM process to that resulting from further polishing. The different topographical features were assessed by electron microscopy, energy dispersive X-ray spectrometry, and profilometry. Surface wettability was also determined based on the measurement of the OCA of water and diiodomethane. The biological responses induced in MC3T3 cells, a widely diffused osteoblast model, were correlated with the surface pattern. The unpolished samples could promote better cell viability, with a more relevant effect on the cytoskeleton arrangement as highlighted by numerous cytoplasmic extensions and filopodia-like structures and the high number of focal adhesions, while MC3T3 cells grown on polished SiN-TiN specimens displayed a flat morphology. In addition, the unpolished SiN-TiN increased osteocalcin production and calcium deposition. Taken together, these data support the biocompatibility and in vitro osteogenic properties of the electroconductive SiN-TiN investigated. Further in vivo studies are required to explore the possible use of bone implants directly obtained by EDM. [ABSTRACT FROM AUTHOR]

Bone plays several physiological functions and is the second most commonly transplanted tissue after blood. Since the treatment of large bone defects is still unsatisfactory, researchers have endeavoured to obtain scaffolds able to release growth and differentiation factors for mesenchymal stem cells, osteoblasts and endothelial cells in order to obtain faster mineralization and prompt a reliable vascularization. Nowadays, the application of osteoblastic cultures spans from cell physiology and pharmacology to cytocompatibility measurement and osteogenic potential evaluation of novel biomaterials. To overcome the simple traditional monocultures in vitro, co-cultures of osteogenic and vasculogenic precursors were introduced with very interesting results. Increasingly complex culture systems have been developed, where cells are seeded on proper scaffolds and stimulated so as to mimic the physiological conditions more accurately. These bioreactors aim at enabling bone regeneration by incorporating different cells types into bio-inspired materials within a surveilled habitat. This review is focused on the most recent developments in the organomimetic cultures of osteoblasts and vascular endothelial cells for bone tissue engineering. [ABSTRACT FROM AUTHOR]