Immune Dysfunction in Medication-Related Osteonecrosis of the Jaw.

The pathogenesis of medication-related osteonecrosis of the jaw (MRONJ) is multifactorial and there is a substantial consensus on the role of antiresorptive drugs (ARDs), including bisphosphonates (BPs) and denosumab (Dmab), as one of the main determinants. The time exposure, cumulative dose and administration intensity of these drugs are critical parameters to be considered in the treatment of patients, as cancer patients show the highest incidence of MRONJ. BPs and Dmab have distinct mechanisms of action on bone, but they also exert different effects on immune subsets which interact with bone cells, thus contributing to the onset of MRONJ. Here, we summarized the main effects of ARDs on the different immune cell subsets, which consequently affect bone cells, particularly osteoclasts and osteoblasts. Data from animal models and MRONJ patients showed a deep interference of ARDs in modulating immune cells, even though a large part of the literature concerns the effects of BPs and there is a lack of data on Dmab, demonstrating the need to further studies.

Flexibility of Bayesian generalized linear mixed models for oral health research.

Many outcome variables in oral research are characterized by positive values and heavy skewness in the right tail. Examples are provided by many distributions of dental variables such as DMF (decayed, missing, filled teeth) scores, oral health impact profile score, gingival index scores, and microbiologic counts. Moreover, heterogeneity in data arises when more than one tooth is studied for each patient, due to the clusterization.Over the past decade, linear mixed models (LMEs) have become a common statistical tool to account for within-subject correlation in data with repeated measures. When a normal error is reasonably assumed, estimates of LMEs are supported by many statistical packages. Such is not the case for skewed data, where generalized linear mixed models (GLMMs) are required. However, the current software available supports only special cases of GLMMs or relies on crude Laplace-type approximation of integrals. In this study, a Bayesian approach is taken to estimate GLMMs for clustered skewed dental data. A Gamma GLMM and a log-normal model are employed to allow for heterogeneity across clusters, deriving from the patient-operator-tooth susceptibility typical of this clinical context. A comparison to the frequentist framework is also provided. In our case, Gamma GLMM fits data better than the log-normal distribution, while providing more precise estimates compared with the likelihood approach. A key advantage of the Bayesian framework is its ability to readily provide a flexible approach for implementation while simultaneously providing a formal procedure for solving inference problems.

A new coping for overdentures. Part 1: A pilot study of the marginal precision.

The aim of this study was to investigate the marginal precision of new chairside copings prepared on 20 extracted teeth. The marginal fit was examined microscopically through 360-degree external observations. Subsequently, 10 new copings were adapted in vivo on 10 teeth that were planned for extraction. After extraction, the marginal fit was evaluated using the same protocol. The mean values of the marginal gap for the 2 groups (20 and 10 copings) were 24.1 and 32.6 microm, respectively. The marginal precision of the new copings was within the clinically accepted limits.

Dimensional contour stability of acrylic resin bases for complete dentures before and after water sorption.

PURPOSE: To evaluate the dimensional contour variations of acrylic resin denture bases before and after storage in water. MATERIALS AND METHODS: The fit of 40 bases was evaluated by measuring the thickness of a layer made with silicone placed between the bases and the casts. The measurements were repeated on a new set of silicone layers after having stored the bases in water for 42 days. RESULTS: Significant differences were found both for the maxillary and the mandibular bases. CONCLUSION: Water sorption had an important effect on the contour of the prosthetic bases.