Fracture rate of monolithic zirconia restorations up to 5 years: A dental laboratory survey

AbstractStatement of problemThe demand for ceramic restorations has increased over the past years because of their esthetic properties and the high cost of noble metals. However, the lack of long-term clinical studies and the difficulty of interpreting in vitro studies have placed the durability of ceramic restorations in doubt.PurposeThe purpose of this study was to determine the failure rate of monolithic zirconia restorations due to fracture up to 5 years of clinical performance.Material and methodsData were collected over 5 years from 2 commercial dental laboratories. Restorations that were returned to the laboratory for remake because of catastrophic failure (fracture) were identified and included. Restorations were categorized as anterior or posterior. Each category was further divided into complete-coverage single crowns (SCs) and multiple-unit fixed dental prostheses (FDPs). Fracture rates were compared and analyzed using a chi-square test (α=.05).ResultsA total of 39827 restoration records were reviewed and included 3731 anterior restorations (1952 SC; 1799 FDP) and 36096 posterior restorations (29808 SC; 6288 FDP). The overall fracture rate of up to 5 years for all restorations (anterior and posterior) was 1.09%. Fracture rates were 2.06% for all anterior restorations and 0.99% for all posterior restorations. Fracture rates were 0.97% for anterior SCs and 0.69% for posterior SCs, and the combined fracture rate (anterior and posterior) was 0.71%. For FDPs, 3.26% restorations fractured anteriorly and 2.42% fractured posteriorly, and the combined fracture rate (anterior and posterior) was 2.60%.ConclusionWithin the relative short-term evaluation of 5 years, restorations fabricated from monolithic zirconia material displayed relatively low fracture rates. Anterior restorations fractured at a slightly higher rate than posterior restorations, and FDPs fractured at a rate double that of SCs

Oral health-related quality of life changes after placement of immediately loaded single implants in healed alveolar ridges or extraction sockets : a 5-year prospective follow-up study

Objectives: The impact of single implants on oral health-related quality of life (OHRQoL) is scarcely investigated, especially when combined with immediate placement and loading in extraction sockets. The aim was to describe prospectively the changes of OHRQoL with single implants placed in the esthetic zone in healed ridges or in extraction sockets after 5 years. Material and Methods: Ninety-six patients, enrolled at three clinical centers, received 102 single implants placed in a healed ridge (n = 54 implants/50 patients) or in extraction sockets (n = 48 implants/46 patients). Implants were immediately provisionalized, and permanent crowns were cemented after 12 weeks. Oral health impact profile questionnaires (OHIP-14) were completed before surgery, after 1 (provisional crown), 6 (permanent crown), 12 and 60 months, respectively. The overall OHIP-14 score pertains to seven domains with two items each and was assessed on a Likert scale of 0–4 (0 = never and 4 = very often). The evolution of the total OHIP-14 score and changes within all OHIP domains over time and between groups were assessed with a linear mixed-effect model analysis. Results: After 5 years, overall implant survival was 98%. The total OHIP-14 score for both groups combined decreased from 0.50 at baseline to 0.17 at 6 months (P < 0.001), indicative of improvement. For both groups, this remained stable up to 5 years (P = 0.41). However, after 5 years, the total OHIP-14 score revealed a statistically significantly higher improvement in the healed group compared with the extraction group (P = 0.027). Conclusion: Missing a single tooth in the maxillary esthetic zone leads to limited OHRQoL problems as reflected by a low overall OHIP score. However, OHRQoL improves less in the extraction group, reflecting that replacing a missing tooth is perceived as more beneficial than replacing a present tooth

Detecting automorphic orbits in free groups

We present an effective algorithm for detecting automorphic orbits in free groups, as well as a number of algorithmic improvements of train tracks for free group automorphisms.Comment: 24 pages, 2 figure

Proliferation of preosteoblasts on TiO 2 nanotubes is FAK/RhoA related

Model for FAK/RhoA modulation of topography-regulated proliferation

RhoA-Mediated Functions in C3H10T1/2 Osteoprogenitors Are Substrate Topography Dependent: TOPOGRAPHY-DEPENDENT RhoA MEDIATED FUNCTIONS

Surface topography broadly influences cellular responses. Adherent cell activities are regulated, in part, by RhoA, a member of the Rho-family of GTPases. In this study, we evaluated the influence of surface topography on RhoA activity and associated cellular functions. The murine mesenchymal stem cell line C3H10T1/2 cells (osteoprogenitor cells) were cultured on titanium substrates with smooth topography (S), microtopography (M), and nanotopography (N) to evaluate the effect of surface topography on RhoA-mediated functions (cell spreading, adhesion, migration, and osteogenic differentiation). The influence of RhoA activity in the context of surface topography was also elucidated using RhoA pharmacologic inhibitor. Following adhesion, M and N adherent cells developed multiple projections, while S adherent cells had flattened and widespread morphology. RhoA inhibitor induced remarkable longer and thinner cytoplasmic projections on all surfaces. Cell adhesion and osteogenic differentiation was topography dependent with S < M and N surfaces. RhoA inhibition increased adhesion on S and M surfaces, but not N surfaces. Cell migration in a wound healing assay was greater on S versus M versus N surfaces and RhoA inhibitor increased S adherent cell migration, but not N adherent cell migration. RhoA inhibitor enhanced osteogenic differentiation in S adherent cells, but not M or N adherent cells. RhoA activity was surface topography roughness dependent (S < M, N). RhoA activity and -mediated functions are influenced by surface topography. Smooth surface adherent cells appear highly sensitive to RhoA function, while nano-scale topography adherent cell may utilize alternative cellular signaling pathway(s) to influence adherent cellular functions regardless of RhoA activity

Effects of titanium surface anodization with CaP incorporation on human osteoblastic response

In this study we investigated whether anodization with calcium phosphate (CaP) incorporation (Vulcano®) enhances growth factors secretion, osteoblast-specific gene expression, and cell viability, when compared to acid etched surfaces (Porous®) and machined surfaces (Screw®) after 3 and 7 days. Results showed significant cell viability for Porous and Vulcano at day 7, when compared with Screw (p=0.005). At the same time point, significant differences regarding runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and bone sialoprotein (BSP) expression were found for all surfaces (p0.05). Although no significant correlation was found for growth factors secretion and Runx2 expression, a significant positive correlation between this gene and ALP/BSP expression showed that their strong association is independent on the type of surface. The incorporation of CaP affected the biological parameters evaluated similar to surfaces just acid etched. The results presented here support the observations that roughness also may play an important role in determining cell response

Removable partial dentures: The clinical need for innovation

Statement of problem: The number of partially dentate adults is increasing, and many patients will require replacement of missing teeth. Although current treatment options also include fixed partial dentures and implants, removable partial dentures (RPDs) can have advantages and are widely used in clinical practice. However, a significant need exists to advance materials and fabrication technologies because of the unwanted health consequences associated with current RPDs. Purpose: The purpose of this review was to assess the current state of and future need for prosthetics such as RPDs for patients with partial edentulism, highlight areas of weakness, and outline possible solutions to issues that affect patient satisfaction and the use of RPDs. Material and methods: The data on treatment for partial edentulism were reviewed and summarized with a focus on currently available and future RPD designs, materials, means of production, and impact on oral health. Data on patient satisfaction and compliance with RPD treatment were also reviewed to assess patient-centered care. Results: Design, materials, ease of repair, patient education, and follow-up for RPD treatment all had a significant impact on treatment success. Almost 40% of patients no longer use their RPD within 5 years because of factors such as sociodemographics, pain, and esthetics. Research on RPD-based treatment for partial edentulism for both disease-oriented and patient-centered outcomes is lacking. Conclusions: Future trials should evaluate new RPD materials and design technologies and include both long-term follow-up and health-related and patient-reported outcomes. Advances in materials and digital design/production along with patient education promise to further the application of RPDs and improve the quality of life for patients requiring RPDs

Groups, Graphs, Languages, Automata, Games and Second-order Monadic Logic

In this paper we survey some surprising connections between group theory, the theory of automata and formal languages, the theory of ends, infinite games of perfect information, and monadic second-order logic