Fracture Resistance of Zirconia Oral Implants In Vitro: A Systematic Review and Meta-Analysis

Various protocols are available to preclinically assess the fracture resistance of zirconia oral implants. The objective of the present review was to determine the impact of different treatments (dynamic loading, hydrothermal aging) and implant features (e.g., material, design or manufacturing) on the fracture resistance of zirconia implants. An electronic screening of two databases (MEDLINE/Pubmed, Embase) was performed. Investigations including > 5 screw-shaped implants providing information to calculate the bending moment at the time point of static loading to fracture were considered. Data was extracted and meta-analyses were conducted using multilevel mixed-effects generalized linear models (GLMs). The Šidák method was used to correct for multiple testing. The initial search resulted in 1864 articles, and finally 19 investigations loading 731 zirconia implants to fracture were analyzed. In general, fracture resistance was affected by the implant design (1-piece > 2-piece, p = 0.004), material (alumina-toughened zirconia/ATZ > yttria-stabilized tetragonal zirconia polycrystal/Y-TZP, p = 0.002) and abutment preparation (untouched > modified/grinded, p < 0.001). In case of 2-piece implants, the amount of dynamic loading cycles prior to static loading (p < 0.001) or anatomical crown supply (p < 0.001) negatively affected the outcome. No impact was found for hydrothermal aging. Heterogeneous findings of the present review highlight the importance of thoroughly and individually evaluating the fracture resistance of every zirconia implant system prior to market release

Response of osteoblast-like cells cultured on zirconia to bone morphogenetic protein-2

Purpose: The aim of this study was to compare osteoblast behavior on zirconia and titanium under conditions cultured with bone morphogenetic protein-2. Methods: MC 3T 3-E1 cells were cultured on sandblasted zirconia and sandblasted/etched titanium discs. At 24 hours after seeding MC 3T 3-E1, the demineralized bone matrix (DBM) gel alone and the DBM gel with bone morphogenetic protein-2 (BMP-2) were added to the culture medium. The surface topography was examined by confocal laser scanning microscopy. Cellular proliferation was measured at 1, 4, and 7 days after gel loading. Alkaline phosphatase activity was measured at 7 days after gel loading. The mRNA expression of ALPase, bone sialoprotein, type I collagen, runt-related transcription factor 2 (Runx-2), osteocalcin, and osterix were evaluated by real-time polymerase chain reaction at 4 days and 7 days. Results: At 1, 4, and 7 days after loading the DBM gel alone and the DBM gel with BMP-2, cellular proliferation on the zirconia and titanium discs was similar and that of the groups cultured with the DBM gel alone and the DBM gel with BMP-2 was not significantly different, except for titanium with BMP-2 gel. ALPase activity was higher in the cells cultured with BMP-2 than in the other groups, but there was no difference between the zirconia and titanium. In ALPase, bone sialoprotein, osteocalcin, Runx-2 and osterix gene expression, that of cells on zirconia or titanium with BMP-2 gel was much more highly increased than titanium without gel at day 7. The gene expression level of cells cultured on zirconia with BMP-2 was higher than that on titanium with BMP-2 at day 7. Conclusions: The data in this study demonstrate that the osteoblastic cell attachment and proliferation of zirconia were comparable to those of titanium. With the stimulation of BMP-2, zirconia has a more pronounced effect on the proliferation and differentiation of the osteoblastic cells compared with titanium. ⓒ 2011 Korean Academy of Periodontology

Tooth Reduction Guide Using Silicone Registration Material Along with Vacuum-Formed Thermoplastic Matrix

Adequate tooth reduction is a prerequisite for function, esthetics, and longevity of fixed restorations. A tooth reduction guide may be useful for establishing the proper angulation of the tooth and maximizing periodontal health and restorative success. This article describes a simple and versatile technique for an accurate evaluation of tooth reduction for fixed restorations by using a color-contrasting positive guide of a silicone occlusal registration material processed inside a vacuum-formed clear thermoplastic matrix.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73355/1/j.1532-849X.2009.00506.x.pd

Identification of Zirconia Particle Uptake in Human Osteoblasts by ToF-SIMS Analysis and Particle-Size Effects on Cell Metabolism

As the use of zirconia-based nano-ceramics is rising in dentistry, the examination of possible biological effects caused by released nanoparticles on oral target tissues, such as bone, is gaining importance. The aim of this investigation was to identify a possible internalization of differently sized zirconia nanoparticles (ZrNP) into human osteoblasts applying Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and to examine whether ZrNP exposure affected the metabolic activity of the cells. Since ToF-SIMS has a low probing depth (about 5 nm), visualizing the ZrNP required the controlled erosion of the sample by oxygen bombardment. This procedure removed organic matter, uncovering the internalized ZrNP and leaving the hard particles practically unaffected. It was demonstrated that osteoblasts internalized ZrNP within 24 h in a size-dependent manner. Regarding the cellular metabolic activity, metabolization of alamarBlue by osteoblasts revealed a size- and time-dependent unfavorable effect of ZrNP, with the smallest ZrNP exerting the most pronounced effect. These findings point to different uptake efficiencies of the differently sized ZrNP by human osteoblasts. Furthermore, it was proven that ToF-SIMS is a powerful technique for the detection of zirconia-based nano/microparticles that can be applied for the cell-based validation of clinically relevant materials at the nano/micro scale

Kehittämispolku iäkkäiden palvelujen henkilöstömitoitus -seurannan tiedonkeruun uudistamiselle

Ikääntyneen väestön toimintakyvyn tukemisesta sekä iäkkäiden sosiaali- ja terveyspalveluista annettu laki (980/2012, ns. vanhuspalvelulaki) uudistui 1.10.2020. Yksi uudistuksista oli iäkkäiden henkilöiden ympärivuorokautisen palveluasumisen (entisen tehostetun palveluasuminen) ja pitkäaikaisen laitoshoidon toimintayksiköissä noudatettavan vähimmäishenkilöstömitoituksen kirjaaminen lakiin. Tähän asti henkilöstömitoitusta oli ohjattu laatusuosituksella. Terveyden ja hyvinvoinnin laitos (myöhemmin THL) on seurannut vuodesta 2013 alkaen lain toimeenpanoa ja toteutumista Vanhuspalvelujen tila -seurannalla käyttäen erillistiedonkeruuta. Tiedonkeruulla on seurattu sekä ympärivuorokautisen palveluasumisen että kotihoidon henkilöstörakennetta ja -määrää, asiakkaiden määrää ja henkilöstömitoitusta toimintayksikkötasoisesti. Henkilöstömitoituksen kirjaaminen lakiin edellytti intensiivisempää seurantaa. Tiedonkeruun syklin tiivistyessä erillistiedonkeruu ei ole mahdollista. Ratkaisuna on siirtyä kertakirjaamisperiaatteella toimivaan tietojärjestelmistä tapahtuvaan tiedonkeruuseen. Tässä työpaperissa kuvataan henkilöstömitoitusseurannan tiedonkeruun tulevien vuosien kehityspolku. Kehityspolun tarkoituksena on ohjata henkilöstömitoituksen tiedonkeruun uudistamisen toimeenpanoa. Kehityspolku on laadittu osana Valtava-hanketta, jossa uudistetaan kansallista sote-tietotuotantoa

Non-Precious Metal Alloy Double Crown-Retained Removable Partial Dentures: A Cross-Sectional In Vivo Investigation.

(1) Background: An alternative material to precious metal alloys are non-precious metal alloys. The material properties of these are different and, therefore, their clinical, biological and mechanical behaviors may also differ. Hence, the purpose of this in vivo investigation was to analyze the clinical and patient-reported outcomes of patients restored with non-precious metal alloy double crown-retained removable partial dentures (NP-D-RPDs). (2) Methods: Partially edentulous patients were restored with non-precious metal alloy partially veneered NP-D-RPDs. Survival rates, success rates, failures and patient-reported outcomes were investigated and statistically evaluated. (3) Results: A total of 61 patients (65.6 ± 10.8 years) were included and clinically and radiographically examined. The mean follow-up time was 25.2 ± 16.5 months. In total, 82 NP-D-RPDs and 268 abutment teeth were examined. The overall survival rate of the NP-D-RPDs was 100% after a mean follow-up time of 2.1 years. The overall success rate was 68.3%. The overall satisfaction with the NP-D-RPDs was 94.3%. (4) Conclusions: Non-precious metal alloy partially veneered NP-D-RPDs seem to be an efficient alternative to precious metal alloy RPDs with excellent patient-reported outcomes

Clinical Outcomes of Zirconia Dental Implants: A Systematic Review

To determine the survival rate and marginal bone loss (MBL) of zirconia dental implants restored with single crowns or fixed dental prostheses. An electronic search was conducted up to November 2015 (without any restriction regarding the publication time) through the databases MEDLINE (PubMed), Cochrane Library, and EMBASE to identify randomized controlled clinical trials and prospective clinical trials including >15 patients. Primary outcomes were survival rate and MBL. Furthermore, the influence of several covariates on MBL was evaluated. Qualitative assessment and statistical analyses were performed. This review was conducted according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines for systematic reviews. With the applied search strategy, 4,196 titles could be identified. After a screening procedure, 2 randomized controlled clinical trials and 7 prospective clinical trials remained for analyses. In these trials, a total of 326 patients received 398 implants. The follow-up ranged from 12 to 60 mo. Implant loss was mostly reported within the first year, especially within the healing period. Thereafter, nearly constant survival curves could be observed. Therefore, separate meta-analyses were performed for the first and subsequent years, resulting in an implant survival rate of 95.6% (95% confidence interval: 93.3% to 97.9%) after 12 mo and, thereafter, an expected decrease of 0.05% per year (0.25% after 5 y). Additionally, a meta-analysis was conducted for the mean MBL after 12 mo, resulting in 0.79 mm (95% confidence interval: 0.73 to 0.86 mm). Implant bulk material and design, restoration type, and the application of minor augmentation procedures during surgery, as well as the modes of temporization and loading, had no statistically significant influence on MBL. The short-term cumulative survival rates and the MBL of zirconia implants in the presented systematic review are promising. However, additional data are still needed to confirm the long-term predictability of these implants