Effects of Surface Charges on Dental Implants: Past, Present, and Future

Osseointegration is a major factor influencing the success of dental implantation. To achieve rapid and strong, durable osseointegration, biomaterial researchers have investigated various surface treatment methods for dental subgingival titanium (Ti) implants. This paper focuses on surface-charge modification on the surface of titanium dental implants, which is a relatively new and very promising methodology for improving the implants’ osseointegration properties. We give an overview on both theoretical explanations on how surface-charge affects the implants' osseointegration, as well as a potential surface charge modification method using sandblasting. Additionally, we discuss insights on the important factors affecting effectiveness of surface-charge modification methods and point out several interesting directions for future investigations on this topic

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

The role of liquid resin in orthodontic bonding : toxicological, bond strength and clinical aspects

Dental acrylic composites are rarely fully polymerized in situ. Their unpolymerized components are related to undesirable occupational exposure to dental, particularly orthodontic, personnel. The aim of this study was to design a simple, compatible and reproducible cytotoxicity test which allows the evaluation of the cytotoxicity of orthodontic bonding composites. Based on these data, an alternative bracket bonding technique, which possibly reduces the dose of the irritants in these composites, was studied. Four experimental designs of cell/material exposure patterns were evaluated. Standardized sterile glass slices were placed directly above, directly below and in a tissue culture insert above cell cultures of human oral fibroblasts (HOFs). The vitalities and viabilities of these designs were compared to that of the control HOFs by tetrazolium bromide reduction (MTT) and 3H-thymidine uptake (TdR) assays for up to six days. The reproducibilities of all the designs were compared to that of HOFs. The effects of six commercial acrylic resins on the vitalities and viabilities of HOFs were assessed by MTT and TdR assays over a 6-day period. The use of tissue culture insert in our experimental design, assessed by MTT assay, was shown to be a simple, compatible and reproducible test for cytotoxicity screening of dental acrylic resins. To compare the cytotoxic properties of the oxygen inhibited layer (OIL) and other leachable components of orthodontic bonding composites, seven commercial products were tested. In the absence of OIL, orthodontic bonding composites were not significantly cytotoxic. The presence of OIL caused an average of 33% reduction in the vitalities of HOFs. In the absence of OIL, light cured and chemically cured 2-paste materials were not cytotoxic in vitro. However, chemically cured liquid-paste materials significantly reduced the average vitalities of HOFs. An alternative bonding technique, which possibly reduces the occupational exposure of orthodontic personnel to the cytotoxic liquid resin, was studied. Two orthodontic bonding composites were used in an in vitro mechanical test. In the control group, metal brackets were bonded to extracted healthy human premolars with these materials according to the manufacturers' instructions. In the test group, the liquid resins supplied with these products were not used to bond orthodontic brackets. The specimens were tested for shear bond strength after a standardized storage procedure. Enamel adhesions produced by these two commercial materials with and without the use of liquid resins were similar in their early in vitro shear bond strength. The relevance of the in vitro mechanical data was substantiated by a retrospective clinical study. In the control group, bonding composite and its liquid resin were used to bond fixed appliances onto patients' upper teeth. In the test group, bonding composite without liquid resin was used. The duration of appliance survival was statistically analyzed. Supra-gingival orthodontic metal brackets seemed to bond to and work on healthy enamel surfaces equally well in both test and control groups

Effects of surface charges on dental implants: past, present, and future

Osseointegration is a major factor influencing the success of dental implantation. To achieve rapid and strong, durable osseointegration, biomaterial researchers have investigated various surface treatment methods for dental subgingival titanium (Ti) implants. This paper focuses on surface-charge modification on the surface of titanium dental implants, which is a relatively new and very promising methodology for improving the implants&apos; osseointegration properties. We give an overview on both theoretical explanations on how surface-charge affects the implants&apos; osseointegration, as well as a potential surface charge modification method using sandblasting. Additionally, we discuss insights on the important factors affecting effectiveness of surface-charge modification methods and point out several interesting directions for future investigations on this topic

How does mandibular advancement with or without maxillary procedures affect pharyngeal airways? An overview of systematic reviews

<div><p>Background</p><p>Mandibular advancement surgery may positively affect pharyngeal airways and therefore potentially beneficial to obstructive sleep apnea (OSA).</p><p>Objective</p><p>To collect evidence from published systematic reviews that have evaluated pharyngeal airway changes related to mandibular advancement with or without maxillary procedures.</p><p>Methodology</p><p>PubMed, EMBASE, Web of Science, and Cochrane Library were searched without limiting language or timeline. Eligible systematic reviews evaluating changes in pharyngeal airway dimensions and respiratory parameters after mandibular advancement with or without maxillary surgery were identified and included.</p><p>Results</p><p>This overview has included eleven systematic reviews. Maxillomandibular advancement (MMA) increases linear, cross-sectional plane and volumetric measurements of pharyngeal airways significantly (p<0.0001), while reducing the apnea-hypopnea index (AHI) and the respiratory disturbance index (RDI) significantly (p<0.0001). Two systematic reviews included primary studies that have evaluated single-jaw mandibular advancement, but did not discuss their effect onto pharyngeal airways. Based on the included primary studies of those systematic reviews, single-jaw mandibular advancement was reported to significantly increase pharyngeal airway dimensions (p<0.05); however, conclusive long-term results were lacking.</p><p>Conclusion</p><p>MMA increases pharyngeal airway dimensions and is beneficial to patients suffering from OSA. However, more evidence is still needed to draw definite conclusion related to the effect of single-jaw mandibular advancement osteotomies on pharyngeal airways.</p></div

Funnel plot for primary studies of mandibular setback with maxillary advancement surgeries.

<p>Funnel plot for primary studies of mandibular setback with maxillary advancement surgeries.</p

Funnel plot for primary studies of mandibular setback surgeries.

<p>Funnel plot for primary studies of mandibular setback surgeries.</p

Results from multiple meta-analyses of MMA procedures reported by included systematic reviews.

<p>Results from multiple meta-analyses of MMA procedures reported by included systematic reviews.</p

Quality assessment for primary studies of included systematic reviews.

<p>Quality assessment for primary studies of included systematic reviews.</p

Anteroposterior (AP) changes of OP airway at multiple measurement locations (based on meta-analyses results reported by Mattos <i>et al</i>[18]).

<p>Anteroposterior (AP) changes of OP airway at multiple measurement locations (based on meta-analyses results reported by Mattos <i>et al</i>[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0185951#pone.0185951.ref018" target="_blank">18</a>]).</p