Explore the vast range of titles available.

Univariate continuous distributions are one of the fundamental components on which statistical modelling, ancient and modern, frequentist and Bayesian, multi-dimensional and complex, is based. In this article, I review and compare some of the main general techniques for providing families of typically unimodal distributions on ℝ with one or two, or possibly even three, shape parameters, controlling skewness and/or tailweight, in addition to their all-important location and scale parameters. One important and useful family is comprised of the 'skew-symmetric' distributions brought to prominence by Azzalini. As these are covered in considerable detail elsewhere in the literature, I focus more on their complements and competitors. Principal among these are distributions formed by transforming random variables, by what I call 'transformation of scale'—including two-piece distributions—and by probability integral transformation of nonuniform random variables. I also treat briefly the issues of multi-variate extension, of distributions on subsets of ℝ and of distributions on the circle. The review and comparison is not comprehensive, necessarily being selective and therefore somewhat personal.

Bayesian variable selection often assumes normality, but the effects of model misspecification are not sufficiently understood. There are sound reasons behind this assumption, particularly for large p: ease of interpretation, analytical, and computational convenience. More flexible frameworks exist, including semi- or nonparametric models, often at the cost of some tractability. We propose a simple extension that allows for skewness and thicker-than-normal tails but preserves tractability. It leads to easy interpretation and a log-concave likelihood that facilitates optimization and integration. We characterize asymptotically parameter estimation and Bayes factor rates, under certain model misspecification. Under suitable conditions, misspecified Bayes factors induce sparsity at the same rates than under the correct model. However, the rates to detect signal change by an exponential factor, often reducing sensitivity. These deficiencies can be ameliorated by inferring the error distribution, a simple strategy that can improve inference substantially. Our work focuses on the likelihood and can be combined with any likelihood penalty or prior, but here we focus on nonlocal priors to induce extra sparsity and ameliorate finite-sample effects caused by misspecification. We show the importance of considering the likelihood rather than solely the prior, for Bayesian variable selection. The methodology is in R package 'mombf.'  Supplementary materials for this article are available online.

Background/objectives: Zirconia dental implants are increasingly recognised as an alternative to titanium implants due to their biocompatibility and aesthetics. Initially developed as one-piece systems, zirconia implants have evolved into two-piece designs with different platform levels; however, comparative data on their primary and secondary stability– particularly as assessed by resonance frequency analysis (RFA)—and marginal bone dynamics remain limited. This case series aimed to evaluate the implant stability and marginal bone changes of two-piece zirconia implants with bone-level (BL) and tissue-level (TL) platforms in patients missing maxillary premolars. Methods: Thirteen zirconia implants (n = 13; 7 BL, 6 TL; Z5-TL/Z5-BL, Z-Systems, Switzerland) were placed in 11 patients with healed ridges. The implant stability quotient (ISQ) was measured immediately after insertion and before prosthetic loading. Lithium disilicate crowns were cemented after four months, and follow-ups were conducted for an average of 35 months (SD = 12). Results: Initial ISQ values ranged from 73 to 79, increasing to 76–84 at 3–4 months, indicating high implant stability for both BL and TL implants. The extent of marginal bone loss (MBL) after two years was greater around BL implants (mean 0.46 mm) compared to TL implants (mean 0.2 mm), although probing depths and bleeding on probing remained minimal in both groups, with only one TL implant showing gingival recession. Conclusions: Over a short observation period, two-piece zirconia implants with tissue-level platforms appeared to demonstrate superior marginal tissue stability. Further, larger-scale controlled studies are required to confirm these preliminary observations.

Objectives: The aim of this retrospective study was to evaluate the long-term clinical and radiographic performance of zirconia dental implants with one-piece and two-piece configurations supporting single-tooth restorations. The primary outcome was implant survival, while the secondary outcome was the assessment of interproximal marginal bone loss (MBL) over time. Materials and methods: A total of 67 implants placed in 55 patients were included, with a mean follow-up of 60.6 months. Forty-five implants were one-piece systems and twenty-two were two-piece systems. All surgical and prosthetic procedures were performed by the same operator, following the manufacturer’s recommendations. Final restorations were delivered three months after implant placement. Marginal bone levels were assessed radiographically at the time of definitive prosthesis delivery (T0) and at the last follow-up examination (T1). Statistical significance level was set at 5% (α = 0.05). Results: The overall implant survival rate was 100% in both groups. One-piece implants showed higher initial MBL values than two-piece implants; however, bone level changes over time were limited in both configurations, with no significant intra-group differences between T0 and T1. Conclusions: Both implant configurations showed excellent clinical and radiographic outcomes, with a 100% survival rate and limited marginal bone loss during long-term follow-up. Marginal bone levels appeared to be influenced more by implant neck design than by implant configuration, suggesting that zirconia implants with a smooth transmucosal design may represent a reliable metal-free option for single-tooth rehabilitation in properly selected patients.

Background Correct choice of the implant design and the occlusal scheme is important for the success of implant supported restorations. So, the aim of the current study was to find out the difference in the stresses induced by the one piece dental implants designed to be used in the All-on-4® concept and the conventional two piece ones under simulated lateral occlusal schemes using nonlinear finite element analysis. Methods Two finite element models of the maxilla, implants, and prostheses were designed according to the All-on-4® concept. In the model TP, two piece dental implants were placed while in the model OP one piece dental implants were used. Two loading scenarios were applied to each model; the first one simulated a group function occlusal scheme while the second scenario simulated a canine guided one. Results The highest stress value was recorded in the model TP with the group function occlusion and the lowest stress value was in the model OP with the canine guidance occlusion. Conclusion The one-piece dental implants can be concluded to induce less stress compared to the two piece dental implants when used in the All-on-4® implant supported prosthesis in the different lateral occlusal schemes. Canine guided occlusion can be concluded to cause lower stress values in comparison to the group function occlusal scheme.

The study aimed to evaluate a temperature increase in, and damage to, titanium implants during flapless laser debridement. The study analyzed 15 implants with various implant–abutment connections: a two-piece implant (n = 4) with a screw abutment (IA—Implant–Abutment) and a one-piece implant with a ball type fixture (BTF, n = 4) or fix type fixture (FTF, n = 4). The implants were placed in porcine mandibles 2 mm over a bone crest to imitate a peri-implantitis. The implants were debrided in contact mode for 60 s with a Er:YAG laser at fluence of 9.95 J/cm2 (G1 group: 50 mJ/30 Hz); 19.89 J/cm2 (G2 group: 100 mJ/30 Hz); 39.79 J/cm2 (G3 group: 200 mJ/30 Hz), or a scaler with a ceramic tip (G4 control group: 4 W/20 Hz). The temperature was measured with thermocouples at implant and abutment levels. The damage in the titanium surface (n = 3, non-irradiated implants from each type) was assessed using SEM (Scanning Electron Microscopy). The temperature increase at the implant level for the laser was higher at IA in contrast with FTF and BTF. (p < 0.05) The temperature change at the abutment level was lower for the scaler in contrast to Er:YAG laser at FTF. (p < 0.0002) Er:YAG laser didn’t increase the temperature by 10 °C at 100 mJ/30 Hz and 50 mJ/30 Hz. Based on SEM analysis, cracks occurred on the surface of two-piece implants and were more pronounced. Cracks and the melting of the titanium surface of two-piece implants cleaned with Er:YAG laser at 100 or 200 mJ were observed. The specimens treated with the ultrasonic scaler with a plastic curette showed the remaining dark debris on the titanium surface. We recommend using Er:YAG laser at 50 mJ/30 Hz during flapless implants debridement.

The study reviewed the state of the art of the clinical use of a convergent-neck-designed Prama implant. This implant was introduced approximately 10 years ago and was characterized by a specific and unique convergent neck with a microtextured surface (UTM surface) and Zirconium Titanium (ZirTi) implant body surface. The neck design was developed to adopt the biologically oriented preparation technique (BOPT). A critical analysis of the published clinical studies and an evaluation of the adopted clinical protocols were performed. A total of forty-six articles were eligible to be reviewed. Only sixteen clinical studies reported clinical outcomes on Prama implants, and nine of these were selected having the longest follow-up from different research groups. The clinical follow-up/duration of the studies ranged from 12 months to 6 years. The initially proposed protocols explored neck supracrestal–transmucosal placement and gained interest due to its minimally invasive concept and the ability to proceed without a pre-prosthesis second surgery. The following investigations dedicated attention to the subcrestal or equicrestal implant placement with the conventional flap approach. The clinical studies characterized by the transmucosal exposed neck approach reported high survival rates with a stable bone morphology and reduced bone loss during the follow-up. Further recent implementations included the introduction of different convergent neck heights that need to be evaluated. The use of intraoral scanner technologies and digital workflow resulted in a simpler methodology with control of the marginal crown morphology. The studies support the concept that the hard tissue parameters (such as marginal bone level, MBL) and soft tissue parameters (such as pink esthetic score, PES) were stable or improved during the follow-up. Definitive crowns, designed with low invasiveness for soft tissues, were possible thanks to the morphology of the neck. The clinical studies support the use of the Prama implant with the different neck positions, demonstrating hard tissue preservation and optimal esthetic results in the first years following insertion. However, the current body of evidence is not robust enough to draw definitive conclusions, especially in the long term, and further high-quality research (long-term randomized trials) is required to consolidate these early observations.

We construct a flexible dynamic linear model for the analysis and prediction of multivariate time series, assuming a two-piece normal initial distribution for the state vector. We derive a novel Kalman filter for this model, obtaining a two components mixture as predictive and filtering distributions. In order to estimate the covariance of the error sequences, we develop a Gibbs-sampling algorithm to perform Bayesian inference. The proposed approach is validated and compared with a Gaussian dynamic linear model in simulations and on a real data set.

PurposeFully formed knitting technology is a cutting-edge technology in the design and production of knitted apparel. Using this technology and its supporting design system, a new development mode of fully formed knitted apparel with double-layer structure and fake two-piece knitwear is proposed.Design/methodology/approachBased on the upper body structure feature points of human body characteristics and single-layer knitted garment prototype, a double-layer structure knitted garment pattern was established by pattern expansion method. The model was introduced into SDS-APPEX3 design system for process design, including three aspects consists: the inner vest, the outer blouse and double-layer joint part, analysis of the process and forming principle. Weaving on four-needle bed computerized flat knitting machine of MACH-2XS, through the setting of the machine parameters. Finally, a full-shaped fake two-piece knitted blouse was formed.FindingsOn the basis of single-layer knitted garment pattern, a double-layer garment pattern is constructed, and the design and weaving are completed on the four-needle bed computerized knitting machine of MACH-2XS and its supporting SDS-APPEX3 design system through the fake two-piece double-layer garment style design. The double-layer joint model is an effective reference for the construction of this kind of fake two-piece fully formed knitted clothing.Originality/valueIn this paper, a design and knitting method of fully formed double-layer structure fake two-piece knitted garment is proposed. The integrated knitting of fully formed double-layer structure sweater is realized for the first time, which provides ideas for the development of fully formed double-layer structure knitted clothing style and enriches the fully formed clothing style.

The O-rings in ball retained overdentures deteriorate with time and need replacement to restore the retentive quality. We evaluated retrospectively the mechanical properties of O-rings after 3 years in function in 1 and 2-piece implant-supported overdentures. The O-rings were retrieved from one-piece (Myriad snap, Equinox-Straumann, 3.3 × 13 mm) and 2-piece (Neo Biotech, 3.3 × 13 mm) implant-supported overdenture patients. A total of 16 pairs of matrices were tested for wear, type of damage, and elasticity using Pin on Disc method, USB Digital Camera in 30× zoom and Universal Tensile Machine, respectively. The statistical analysis for independent groups were done with the Mann-Whitney U test. Assessment of used O-rings showed 84% more wear in the 2-piece system with an abrasive type of damage while 46% wear in the 1-piece system with a compressive type of damage. The O-rings in 1-piece system showed increase in elongation and maximum displacement to 2% and 7%, respectively, whereas the 2-piece system showed decrease in elongation and maximum displacement by 13% and 6%, respectively. In 1-piece system, the loss of retention was more with slow wear rate, and in 2-piece system, the wear resistance of O-rings decreased due to increased stiffness. Further studies to evaluate the changes in O-ring with increased sample size and at interval 1 year will pave way for insight into the progressive changes in the mechanical properties of an O-ring.