Transnational health protection strategies and other health-seeking behavior among undocumented and indigenous dairy workers in a rural new immigrant destination.

Latin American immigrants in new immigrant destinations (NIDs) experience numerous barriers that negatively impact their access to healthcare. Yet the wide range of health-seeking behaviors deployed in response to these barriers-particularly among those who are undocumented and indigenous-are not well understood. Further, studies of immigrant health in NIDs tend to take place in those locations, rather than using a multi-sited design.

Sutural growth restriction and modern human facial evolution: an experimental study in a pig model.

Facial size reduction and facial retraction are key features that distinguish modern humans from archaic Homo. In order to more fully understand the emergence of modern human craniofacial form, it is necessary to understand the underlying evolutionary basis for these defining characteristics. Although it is well established that the cranial base exerts considerable influence on the evolutionary and ontogenetic development of facial form, less emphasis has been placed on developmental factors intrinsic to the facial skeleton proper.

Seasonal timing of diapause induction limits the effective range of Diorhabda elongata deserticola (Coleoptera: Chrysomelidae) as a biological control agent for tamarisk (Tamarix spp.).

The leaf beetle Diorhabda elongata Brullé subspecies deserticola Chen, collected in northwestern China, has been released in the western United States to control tamarisk (Tamarix spp.). While beetle establishment and saltcedar defoliation have been noted at northern study sites, this species has not established at latitudes south of the 38th parallel.

Effect of glucocorticoid-induced osteoporotic-like conditions on osteoblast cell attachment to implant surface microtopographies.

Objectives: The objectives of this work were to: (1) establish methodology for pretreating osteoblast-like cells in vitro with dexamethasone to cause glucocorticoid-induced osteoporosis, (2) perform quantitative and qualitative assessments of cellular attachment of osteoporosis-like osteoblasts when grown on implant surfaces of differing roughness, (3) and explore the hypothesis that dexamethasone-treated osteoblasts have altered cell attachment properties by focal adhesion disassembly and decreased tyrosine phosphorylation of the focal adhesion tyrosine kinase.

Methods: Osteoblasts were cultured with dexamethasone (10(-7) and 10(-6) M) for up to 4 days of incubation to induce osteoporosis-like conditions. Cellular attachment assays demonstrated the effect of dexamethasone treatments on cellular attachment properties of osteoblasts.

Restricting facial bone growth with skeletal fixation: a preliminary study.

Introduction: Conventional orthodontic treatment of vertical or anterior maxillary excess by growth modification can be problematic in children because of the high levels of patient compliance required. The purpose of this preliminary study was to investigate the use of rigid skeletal fixation to modify facial bone growth without compliance.

Methods: Three 30-day old female pigs from the same litter were included in phase I.

Osteoporosis-like bone conditions affect osseointegration of implants.

Purpose: Usage of dental implants has become common for the treatment of edentulous patients, but concerns exist over the use of implants in patients where orofacial bone loss occurs. In the present study, the osseointegration of implants in rabbits under osteoporosis-like (OP-like) conditions simulating several clinically relevant conditions is reported.

Materials And Methods: Forty rabbits were divided into 4 groups of 10.

Examination of the bone-implant interface in experimentally induced osteoporotic bone.

The objective of this study was to explore the hypothesis that osteoporotic-like (OP) conditions have a negative effect on osseointegration (OI) of dental implants. Using an ovariectomized (OVX) rat model, the extent of OI using histologic and histomorphometric analysis (HMA) under a variety of OVX conditions was assessed. Five experimental groups (n = 7 rats per group) were used: 1) OP control, 2) OI control, () OI followed by OVX treatment to induce OP (OI-->OP), 4) OP induction followed by OI (OP-->OI), and 5) OP induction simultaneously with OI (OI = OP).

Effects of implant microtopography on osteoblast cell attachment.

Purpose: The overall aim of this project was to study osteoblast cell attachment on titanium surfaces with varying surface roughness.

Materials And Methods: Commercially pure titanium surfaces were prepared by polishing through 600-grit sandpaper, sandblasting, or sandblasting followed by acid etching to produce surfaces of varying roughness, as determined by scanning electron microscopy and atomic force microscopy. In vitro cell attachment of MC3T3-E1 osteoblasts was performed on the prepared surfaces in both serum-containing and serum-free media conditions.

Short-term bone responses to hydroxyapatite cement.

Purpose: The purpose of this study was to evaluate the short-term wound healing and repair at the tissue/cement interface with different hydroxyapatite cement formulations.

Materials And Methods: Three groups of Sprague-Dawley rats were implanted with HAC for 3, 7, or 14 days. The medial femur-tibia sites on each leg of the animals were used to create four separate 1.

Reuse of healing abutments: an in vitro model of plasma cleaning and common sterilization techniques.

The reuse of transgingival healing abutments has been advocated by several implant manufacturers, but cleaning and sterilization procedures to yield clean and optimal surfaces have yet to be developed. The objective of this in vitro project was to investigate various cleaning and sterilization regimens for the removal of biological debris to support reattachment of subgingival connective tissue. Simulated clinical healing abutment surfaces were exposed to culture medium with serum for 1 hour to simulate biological exposure.

Use of hydroxyapatite cement to support implants in extraction sockets.

Bioactive cements based on calcium phosphate chemistry have been developed to serve as bone substitute materials. One such commercial product, BoneSource, is a hydroxyapatite cement (HAC) used for small bone defects in the craniofacial complex. We have investigated the possibility that HAC could be used to support bone growth adjacent to dental implants placed in immediate tooth extraction sites.

The influence of water storage and C-factor on the dentin-resin composite microtensile bond strength and debond pathway utilizing a filled and unfilled adhesive resin.

Objective: To test the elastic wall concept utilizing adhesive resins of varying stiffness in a low- and high-C-factor cavity design after short- and long-term water storage.

Methods: A flat and box-shaped cavity was restored on occlusal dentin with a resin composite using a filled and unfilled adhesive resin from which microtensile specimens with a 0.5mm(2) cross-sectional area were formed.

Mode of failure in the dentin-adhesive resin-resin composite bonded joint as determined by strength-based (muTBS) and fracture-based (CNSB) mechanical testing.

Objective: To determine the failure mode between dentin-adhesive resin-resin composite bonded joint produced with a chevron-notch short-bar (CNSB) and microtensile test methods.

Methods: Forty teeth were randomly selected for microtensile and forty for CNSB specimen fabrication and stored in 0.5% chloramine T at 37 degrees C until respective static load to failure testing at 30 and 180days.

Calcium and phosphate supplementation promotes bone cell mineralization: implications for hydroxyapatite (HA)-enhanced bone formation.

Organic phosphate, in particular beta-glycerophosphate (beta-GP), has been used to induce mineralization in cell culture systems. It serves as a source of inorganic phosphate when hydrolyzed by alkaline phosphatase. This study examined the effect of supplemental calcium and phosphate as well as the influence of various metabolic inhibitors on mineralization in a rat osteoblast-like cell-culture system.

Significant role of adhesion properties of primary osteoblast-like cells in early adhesion events for chondroitin sulfate and dermatan sulfate surface molecules.

The purpose of this study was to characterize the role of cell surface adhesive macromolecules through enzyme modulation and metabolic recovery prior to and during a kinetic cell adhesion assay. Primary rat calvarial osteoblast-like cells were derived from Sprague-Dawley calvarial plates. Cell adhesion kinetics was evaluated with the definition of first-order adhesion kinetics.

Biomechanical and morphometric analysis of hydroxyapatite-coated implants with varying crystallinity.

Purpose: The level of crystallinity in hydroxyapatite (HA) is thought to be responsible for its degradation in the physiologic milieu. The purpose of this study was to compare the in vivo bony response to HA coatings of varying levels of crystallinity and determine the optimum composition for promoting osseointegration.

Materials And Methods: Cylindrical implants of sand-blasted CP titanium and HA-coated titanium of 50% (low), 70% (medium), and 90% (high) crystallinity were inserted into the canine femur for 1, 4, 12, and 26 weeks.

Osteoblastic cell attachment to hydroxyapatite-coated implant surfaces in vitro.

Hydroxyapatite (HA) used as a coating for implants can exhibit varying levels of interaction with the biologic environment. The crystallinity of the HA-based coating has been shown to control the rate of dissolution and appears to play a role in the initial cellular interaction with the implant surfaces. An osteoblastic cell attachment assay was employed to examine the cell attachment to untreated and pretreated (pH 5.

Primary bacterial colonization of implant surfaces.

The purpose of this study was to assess the effects of modifying titanium surfaces, in terms of wettability, roughness, and mode of sterilization, on the ability of the oral bacterium Streptococcus sanguis to colonize. An in vitro model system was developed. All surfaces were colonized by the bacteria, but to significantly different levels.

Tissue compatibility to different surfaces of dental implants: in vitro studies.

Factors affecting cell and tissue responses to dental implant biomaterials are typically characterized as spatial and temporal. Spatially, a dental implant must form an interface with both bone tissue for the development and maintenance of biomechanical stability and soft tissue for the prevention of microbial infection that can lead to peri-implantitis. There is a developing body of knowledge regarding the reactions of host tissues to implant materials, although the specific mechanisms by which these responses are not yet totally understood.

Effect of hybrid layer on fracture toughness of adhesively bonded dentin-resin composite joint.

Objectives: Micromechanical retention from the hybrid layer is generally believed to be the mechanism of adhesion of current generation dentin bonding agents. The purpose of this investigation is to evaluate the interfacial fracture toughness of a commercial dentin bonding agent with and without this hybrid layer.

Methods: Ten extracted molars (AB2) were flattened on the occlusal surface, All-Bond 2 Universal Adhesive System (Bisco) was applied according to manufacturer's directions and a resin composite (Prodigy, Kerr) crown was formed.

Microtensile bond strength testing and failure analysis of two dentin adhesives.

Objectives: This investigation was conducted to determine the tensile bond strength of two dental adhesive using a recently introduced "microtensile" bond strength testing design and to verify the failure mode for each test specimen with scanning electron microscopy (SEM).

Methods: Extracted human molars were mounted in stone and the enamel was removed the occlusal surface perpendicular to the long axis of the tooth. A composite resin crown was formed on this flat dentin surface utilizing each dental adhesive system according to manufacturer's instructions.

A comparative study of osseointegration of titanium implants in autogenous and freeze-dried bone grafts.

Purpose: This study was undertaken to compare the rate and degree of osseointegration of dental implants when placed into either autogenous corticocancellous chip or freeze-dried corticocancellous chip bone grafts.

Materials And Methods: The canine ilium was used as the model site. Thirty experimental and 15 control implants were placed in 15 dogs: autogenous versus freeze-dried corticocancellous chip bone grafts around the exposed implant surfaces.