Clinical and Histological changes after ridge preservation with two xenografts: preliminary results from a multicentre randomized controlled clinical trial.

OBJECTIVES: To evaluate and compare clinical and histological changes after ridge preservation procedures with those of spontaneous healing. MATERIALS AND METHODS: Ninety patients were enrolled in the present randomized controlled clinical trial and underwent single-tooth extraction in the premolar/molar areas. Thirty sites were grafted with collagenated cortico-cancellous (coll), 30 sites with cortical (cort) porcine bone and 30 sites underwent natural healing. Primary (vertical and horizontal bone changes after 3 months) and secondary outcomes (histomorphometric after 3 months) were evaluated at implant placement. RESULTS: The vertical bone changes at the grafted sockets were significantly (p < 0.0001) lower (0.30 mm for cort group and 0.57 mm for coll group) when compared to non-grafted sockets (2.10 mm for nat group). Moreover, the width reduction of the coll (0.93 mm) and cort (1.33 mm) groups was significantly lower (p < 0.0001) than the non-grafted group (3.60 mm). The analysis of subgroups attested that when premolar and molar sites were compared, the buccal bone loss appeared to be dependent both on tooth position and grafting material employed. CONCLUSION: The ridge preservation procedures had significantly better outcomes when compared to natural healing. The biomaterials did not differ for maintenance of bone width; even though, the bone height seemed to be better preserved with the cortical porcine bone.

Porcine dermal matrix in the treatment of dehiscence-type defects--an experimental split-mouth animal trial.

OBJECTIVES: To describe histometrical outcomes (tissue thickness, tissue height) of a porcine dermal matrix (PDX) and subepithelial connective tissue (CTG) in the treatment of dehiscence-type defects. MATERIAL AND METHODS: In five beagle dogs buccal dehiscence defects were created on both upper canines. The defects were covered in a split-mouth design either with a porcine dermal matrix or subepithelial connective tissue. After 4 months histometrical outcomes were evaluated using a nonparametric Brunner-Langer model. RESULTS: Neither in the test nor in the control specimen signs of inflammation or foreign body reaction was detected. Histometrically, no significant difference was found for tissue thickness and height between both treatment groups. CONCLUSIONS: Porcine dermal matrix can be used for grafting of dehiscence-type defects. Augmentation of tissue thickness seems to be comparable to subepithelial connective tissue.

Crooked, coiled and crimpled are three Ly6-like proteins required for proper localization of septate junction components.

Cellular junction formation is an elaborate process that is dependent on the regulated synthesis, assembly and membrane targeting of constituting components. Here, we report on three Drosophila Ly6-like proteins essential for septate junction (SJ) formation. SJs provide a paracellular diffusion barrier and appear molecularly and structurally similar to vertebrate paranodal septate junctions. We show that Crooked (Crok), a small GPI-anchored Ly6-like protein, is required for septa formation and barrier functions. In embryos that lack Crok, SJ components are produced but fail to accumulate at the plasma membrane. Crok is detected in intracellular puncta and acts tissue-autonomously, which suggests that it resides in intracellular vesicles to assist the cell surface localization of SJ components. In addition, we demonstrate that two related Ly6 proteins, Coiled (Cold) and Crimpled (Crim), are required for SJ formation and function in a tissue-autonomous manner, and that Cold also localizes to intracellular vesicles. Specifically, Crok and Cold are required for correct membrane trafficking of Neurexin IV, a central SJ component. The non-redundant requirement for Crok, Cold, Crim and Boudin (Bou; another Ly6 protein that was recently shown to be involved in SJ formation) suggests that members of this conserved family of proteins cooperate in the assembly of SJ components, possibly by promoting core SJ complex formation in intracellular compartments associated with membrane trafficking.

The chloroplast protein CPSAR1, dually localized in the stroma and the inner envelope membrane, is involved in thylakoid biogenesis.

Thylakoid biogenesis is a crucial step for plant development involving the combined action of many cellular actors. CPSAR1 is shown here to be required for the normal organization of mature thylakoid stacks, and ultimately for embryo development. CPSAR1 is a chloroplast protein that has a dual localization in the stroma and the inner envelope membrane, according to microscopy studies and subfractionation analysis. CPSAR1 is close to the Obg nucleotide binding protein subfamily and displays GTPase activity, as demonstrated by in vitro assays. Disruption of the CPSAR1 gene via T-DNA insertion results in the arrest of embryo development. In addition, transmission electron microscopy analysis indicates that mutant embryos are unable to develop thylakoid membranes, and remain white. Unstacked membrane structures resembling single lamellae accumulate in the stroma, and do not assemble into mature thylakoid stacks. CPSAR1 RNA interference induces partially developed thylakoids leading to pale-green embryos. Altogether, the presented data demonstrate that CPSAR1 is a protein essential for the formation of normal thylakoid membranes, and suggest a possible involvement in the initiation of vesicles from the inner envelope membrane for the transfer of lipids to the thylakoids.

A transient luminal chitinous matrix is required to model epithelial tube diameter in the Drosophila trachea.

Epithelial tubes are found in many vital organs and require uniform and correct tube diameters for optimal function. Tube size depends on apical membrane growth and subapical cytoskeletal reorganization, but the cues that coordinate these events to ensure functional tube shape remain elusive. We find that epithelial tubes in the Drosophila trachea require luminal chitin polysaccharides to attain the correct diameter. Tracheal chitin forms a broad transient filament within the tubes during the restricted period of expansion. Loss of chitin causes tubular constrictions and cysts associated with irregular subapical cytoskeletal organization, without affecting epithelial integrity and polarity. Analysis of previously identified tube expansion mutants in genes encoding septate junction proteins further suggests that septate junction components may function in tubulogenesis through their role in luminal matrix assembly. We propose that the transient luminal protein/polysaccharide matrix is sensed by the epithelial cells and coordinates cytoskeletal organization to ensure uniform lumen diameter.

Integrin and chemokine receptor gene expression in implant-adherent cells during early osseointegration.

The mechanisms of early cellular recruitment and interaction to titanium implants are not well understood. The aim of this study was to investigate the expression of pro-inflammatory cytokines, chemokines and adhesion markers during the first 24 h of implantation. Anodically oxidized and machined titanium implants were inserted in rat tibia. After 3, 12, and 24 h the implants were unscrewed and analyzed with quantitative polymerase chain reaction. Immunohistochemistry and scanning electron microscopy revealed different cell types, morphology and adhesion at the two implant surfaces. A greater amount of cells, as indicated by higher expression of small subunit ribosomal RNA (18S), was detected on the oxidized surface. Higher expression of CXC chemokine receptor-4 (at 12 h) and integrins, alphav (at 12 h), beta1 (at 24 h) and beta2 (at 12 and 24 h) was detected at the oxidized surfaces. Significantly higher tumor necrosis factor-alpha (at 3 h) and interleukin-1beta (at 24 h) expression was demonstrated for the machined surface. It is concluded that material surface properties rapidly modulate the expression of receptors important for the recruitment and adhesion of cells which are crucial for the inflammatory and regenerative processes at implant surfaces in vivo.

In Vitro Analysis of the Implant-Abutment Interface Connection and Bacterial Infiltration in Two Extraoral Implant Models.

PURPOSE: To compare the connection microgaps and the bacterial infiltration of implant-abutment interfaces of two extraoral implant models. MATERIALS AND METHODS: Two implant models were used: the inner connection and the flush connection types. The implant-abutment microgaps of five sets of each extraoral implant were evaluated with scanning electron microscopy. Eleven additional sets of each model design were immersed in Staphylococcus aureus cultures for 24 hours, and samples were obtained from the external surface and from the implant's internal chamber to quantify the colony-forming units. RESULTS: Scanning electron microscopy analysis showed that microgaps of the flush connection were smaller compared with the inner connection (P < .0001), and that bacterial counts were higher at the inner connection compared with the flush connection (P < .0001). CONCLUSION: Within the limitations of this experimental study, it can be concluded that the flush connection model presented a smaller microgap and fewer bacterial colonies compared with the inner connection model.

Human NK cell lines migrate differentially in vitro related to matrix interaction and MMP expression.

Matrix metalloproteinases (MMPs) are thought to be of importance for the migratory ability of natural killer (NK) cells. Their expression and production may influence the amount of tumour-infiltrating NK cells and thereby any therapeutic capability. In this study, we sought to investigate the importance of MMPs for human NK cells' ability to degrade and migrate through the extracellular matrix (ECM). The two human NK cell lines, NK-92 and YT, migratory ability, MMP expression and production as well as their morphological appearance when cultured in the ECM equivalent Matrigel were analysed and compared. The quantitatively more migratory NK-92 cells were found to express invadopodia/podosomes at a significantly higher degree when cultured in Matrigel and gave rise to a general disintegration of the Matrigel. The NK-92 cells had a higher mRNA expression of MMP-2, -9, -13, MT1-, MT3- and MT6-MMP and a significantly higher production of MMP-9 compared to YT cells. These differences could explain the substantial functional difference observed between the two cell lines with respect to migratory capacity. In addition, the number of Matrigel invading NK-92 cells decreased significantly in the presence of the MMP inhibitor GM6001, demonstrating that MMPs have a critical function in their migration.

Mandible reconstruction with patient-specific implants: Case report of five consecutive patients.

The purpose of this case report was to assess whether patient-specific implants (PSI: Xillocs) and soft tissue flaps contribute in reconstructing large mandibular defects. Five patients with a medical situation and history not suitable for free microvascular bone flaps were operated with PSI and evaluated. The mean follow-up time was 12 months. The excellent fit, convenient surgery, and esthetic outcome were seen as the major advantages. The PSI can, in the authors' experience, be considered as a useful alternative provided they are well embedded by viable tissue and attached to vital resection margins of the recipient bone.

Quality of life assessment of patients utilizing orbital implant-supported prostheses.

STATEMENT OF PROBLEM: Evaluate the effect of orbital prosthesis retained by implants through a specific quality of life (QOL) questionnaire provides important information on patients QOL, great incentive for the multidisciplinary team and public health support to continue work in this area. PURPOSE: The objective of the study was to evaluate patient satisfaction with orbital implant-supported prostheses using an adapted quality of life questionnaire. MATERIALS AND METHODS: Forty five patients using orbital implant-supported prostheses for a period ranging from six to 120 months. The subjects answered a questionnaire that consisted of 10 questions covering appearance, retention, conspicuousness, self-confidence, difficulty of placement, difficulty of removal, cleaning, limitation of activities, discomfort of tissues, and recommendation of the method to other patients. Answers were expressed using a visual 100-mm scale. The arithmetic mean of the responses was converted into a percentage to represent the satisfaction index. RESULTS: Patients demonstrated a high level of satisfaction on all items, with the lowest rate being for aesthetics and the highest being for recommending the method to other patients. High satisfaction rates regarding the placement and removal of the prosthesis, discomfort to the tissues, and cleaning suggest the ease of handling of the prosthesis. High satisfaction with retention, self-confidence, conspicuousness of the prosthesis, and limitation of activities indicated an association with a better social life. CONCLUSIONS: The results showed that use of bone anchorage technique of extraoral prostheses provided a high level of satisfaction among patients, confirming that osseointegrated implants are a very important resource for the rehabilitation of orbital deformities.

Prevotella bivia can invade human cervix epithelial (HeLa) cells.

Prevotella bivia has been associated with female upper genital tract infections and an increased risk of preterm delivery. In this study, the adherence and invasion capacity of P. bivia was investigated using a cervix epithelial cell line. P. bivia was furthermore analysed for its ability to evoke a proinflammatory cytokine response in epithelial cells. The invasion capacity, defined as the number of bacteria recovered from lysed HeLa cells infected with P. bivia, varied considerably among five strains, all of which were isolates from women with bacterial vaginosis. One P. bivia strain (P47) gave rise to an approximately 120-fold higher number of intracellular bacteria (7 x 10(3) bacteria per 1 x 10(5) cells) compared with the least invasive strain. Three strains expressed an intermediate or low invasiveness, showing an approximately 3- to 40-fold higher number of intracellular bacteria per 1 x 10(5) cells compared with the least invasive strain. The intracellular localization of P47 in phagosome-like vesicles was confirmed by transmission electron microscopy. All P. bivia strains adhered to HeLa cells to the same extent (range 14-22 bacteria per cell) as analysed by interference microscopy. No correlation was found between adhesion and invasion capacity of the strains. Furthermore, no fimbriae-like structures were observed on P47 detected by scanning electron microscopy or negative staining. Analysis of TNF-alpha, IL-1alpha, IL-6, IL-8, and IL-18 in P. bivia-stimulated HeLa cells showed low levels of only IL-6 and IL-8 for the most invasive P. bivia strain P47. Thus, the induction of IL-6 or IL-8 secretion appeared to be associated with invasion capacity. This work provides evidence that some P. bivia isolates can invade human cervix epithelial. Thus, a strong capacity for invasion and a weak proinflammatory cytokine-inducing capacity in P. bivia are suggested to be virulence factors in establishing a low-grade upper genital tract infection.

Breast metastasis around dental implants: a case report.

BACKGROUND: Metastases to the oral cavity and to the jaws are rare; hence, the clinical manifestations of the oral metastasis lesion could frequently be simulating general pathologic entities, making the diagnosis a challenging process to the dental team. Local factors, such as trauma, have been observed to facilitate the growth of blood-borne tumors. To this end, surgical procedures such as fixture placement might cause cancer cells to spread. PURPOSE: Careful clinical examination is a valuable help in diagnosing oral lesions, which can improve the quality of life of patients and reduce the risks of oral complications. MATERIALS AND METHODS: A female patient was referred to the clinic with symptoms of irritation, swelling, and pain associated with implants in the mandible and the maxilla. RESULTS: Clinical examination, x-ray, and histopathology revealed that the patients suffered from a metastatic lesion, primary tumor being an adenocarcinoma of the breast diagnosed at the same time. CONCLUSION: Optimal clinical examination in conjunction with radiography and histopathology is a necessity in order to discover malignant lesions in time. Routine dental check-ups must comprise more thorough soft-tissue examination.

Auricular rehabilitation by means of bone grafting from the iliac crest in combination with porous extraoral implants: a case report.

BACKGROUND: Maxillofacial defects caused by cancer treatment are a huge problem affecting the quality of life of patients. Some of these deformities are minimized using facial epitheses, which need some additional retention devices like glasses or skin adhesives. The use of extraoral fixtures as bone anchorage was introduced many years ago and since then many patients were rehabilitated with better results. PURPOSE: Because of poor bone conditions, for example, irradiated bone, the success rate of extraoral implants is less than in the oral cavity, causing difficulties to rehabilitation. One possible cause of fixture failure could be the poor primary stability achieved in some cases, hence, with an increased bone contact implant stability and survival could be improved. The present report discusses possibilities to use extraoral fixtures with a modified surface structure. MATERIALS AND METHODS: A new porous surfaced Brazilian extraoral implant (MasterExtra, Conexão, Sistema de Próteses, São Paulo, Brazil) was used. A bone transplant from the iliac crest was taken to make it possible to insert at least three extraoral implants for an auricle epithesis. Clinical evaluation and resonance frequency analysis (RFA) measurements were performed during the course of the treatment. RESULTS: Eight months after grafting, four fixtures were inserted. Three fixtures were used for connection of an auricular epithesis. RFA measurements did show high initial values and the values remained stable during the course of the treatment and at later checkups. CONCLUSION: Porous fixture is a good option in areas where the bone is compromised. RFA is a good tool also in the clinical setting to evaluate immediate and long-term stability of extraoral fixtures.

Augmentation of severly resorbed alveolar crests with bovine bone blocks: A human histology pilot study.

BACKGROUND: Allo-/xenogenic bone blocks are used to treat bone defects. Few human histologic studies are found on their integration and capacity to augment new bone. PURPOSE: To study incorporation and stability of collagenated bovine bone blocks (CBB). Short term effects, histology, and morphometry on biopsy specimens are presented. MATERIALS AND METHODS: Nine patients exhibiting extremely narrow alveolar ridges had CBB adapted and fixed to the recipient bone and covered with collagen barriers. At median 6 months healing (range 2-14 months) biopsies were harvested and dental implants placed. Evaluation was done on the handling, primary healing together, and morphologic assessments of the biopsies. RESULTS: New bone varied from 7.7% to 34.5%, lowest value being found in a patient showing graft exposure. Residual biomaterial varied between 2.9% and 48.2%. Implant placement was successful in all cases and all patients were rehabilitated with fixed superstructures. Several critical issues are discussed on the clinical handling of the material for example, soft tissue management and use of barrier membranes. CONCLUSIONS: CBB was found to integrate well in a predictable way. New bone could be seen at early time points and may shorten treatment time with implants in cases with thin alveolar ridges.

Mechanical properties of bacterial cellulose and interactions with smooth muscle cells.

Tissue engineered blood vessels (TEBV) represent an attractive approach for overcoming reconstructive problems associated with vascular diseases by providing small calibre vascular grafts. The aim of this study has been to evaluate a novel biomaterial, bacterial cellulose (BC), as a potential scaffold for TEBV. The morphology of the BC pellicle grown in static culture was investigated with SEM. Mechanical properties of BC were measured in Krebs solution and compared with the properties of porcine carotid arteries and ePTFE grafts. Attachment, proliferation and ingrowth of human smooth muscle cells (SMC) on the BC were analysed in vitro. The BC pellicle had an asymmetric structure composed of a fine network of nanofibrils similar to a collagen network. The shape of the stress-strain response of BC is reminiscent of the stress-strain response of the carotid artery, most probably due to the similarity in architecture of the nanofibrill networks. SMC adhered to and proliferated on the BC pellicle; an ingrowth of up to 40 microm was seen after 2 weeks of culture. BC exhibit attractive properties for use in future TEBV.

In vivo biocompatibility of bacterial cellulose.

The biocompatibility of a scaffold for tissue engineered constructs is essential for the outcome. Bacterial cellulose (BC) consists of completely pure cellulose nanofibrils synthesized by Acetobacter xylinum. BC has high mechanical strength and can be shaped into three-dimensional structures. Cellulose-based materials induce negligible foreign body and inflammatory responses and are considered as biocompatible. The in vivo biocompatibility of BC has never been evaluated systematically. Thus, in the development of tissue engineered constructs with a BC scaffold, it is necessary to evaluate the in vivo biocompatibility. BC was implanted subcutaneously in rats for 1, 4, and 12 weeks. The implants were evaluated in aspects of chronic inflammation, foreign body responses, cell ingrowth, and angiogenesis, using histology, immunohistochemistry, and electron microscopy. There were no macroscopic signs of inflammation around the implants. There were no microscopic signs of inflammation either (i.e., a high number of small cells around the implants or the blood vessels). No fibrotic capsule or giant cells were present. Fibroblasts infiltrated BC, which was well integrated into the host tissue, and did not elicit any chronic inflammatory reactions. The biocompatibility of BC is good and the material has potential to be used as a scaffold in tissue engineering.

The use of a collagenated porcine cortical lamina in the reconstruction of alveolar ridge defects. A clinical and histological study.

BACKGROUND: Alveolar ridge reconstruction by means of resorbable and non-resorbable membranes has been proposed to increase the hard tissue volume in deficient sites. The purpose of this study was therefore to clinically and histologically evaluate the use of collagenated porcine bone lamina in case of horizontal and vertical bone augmentation procedures in conjunction with particulated porcine xenograft. METHODS: Overall, 8 partially edentulous patients (6 females and 2 males) with a mean age of 45 years requiring bone regeneration procedures to achieve a prosthetically driven implant placement were enrolled. All ridge defects were augmented using a xenogeneic cortical bone barrier in combination with particulated heterologous bone. Bone biopsies were collected during the re-entry procedure. RESULTS: A total of 15 implants were placed both simultaneously or in a staged approach in the augmented sites. No complications occurred during the rehabilitation. Histologically, the bone lamina was widely vascularized and integrated with the surrounding soft tissues and the native bone. The presence of osteoclastic lacunae suggested an active remodelling of the particulated graft and a gradual substitution with the newly formed bone. CONCLUSION: Alveolar reconstruction by means of the collagenated cortical lamina gave promising clinical and histological results. The rigidity and the slow resorption pattern allowed for the blood clot protection even in case of vertical defects, avoiding at the same time the re-entry surgery for its removal.

The use of a collagenated porcine cortical lamina in the reconstruction of alveolar ridge defects. A clinical and histological study.

BACKGROUND: Alveolar ridge reconstruction by means of resorbable and non-resorbable membranes has been proposed to increase the hard tissue volume in deficient sites. The purpose of this study was therefore to clinically and histologically evaluate the use of collagenated porcine bone lamina in case of horizontal and vertical bone augmentation procedures in conjunction with particulate porcine xenograft. METHODS: Overall, 8 partially edentulous patients (6 females and 2 males) with a mean age of 45 years requiring bone regeneration procedures to achieve a prosthetically driven implant placement were enrolled. All ridge defects were augmented using a xenogeneic cortical bone barrier in combination with particulate heterologous bone. Bone biopsies were collected during the re-entry procedure. RESULTS: A total of 15 implants were placed both simultaneously or in a staged approach in the augmented sites. No complications occurred during the rehabilitation. Histologically, the bone lamina was widely vascularized and integrated with the surrounding soft tissues and the native bone. The presence of osteoclastic lacunae suggested an active remodeling of the particulate graft and a gradual substitution with the newly formed bone. CONCLUSIONS: Alveolar reconstruction by means of the collagenated cortical lamina gave promising clinical and histological results. The rigidity and the slow resorption pattern allowed for the blood clot protection even in case of vertical defects, avoiding at the same time the re-entry surgery for its removal.

Soft Tissue Integration of Hydroxyapatite-Coated Abutments for Bone Conduction Implants.

PURPOSE: The protocol for bone conduction hearing implant surgery involves reduction of soft tissues around the abutment to minimize the risk of skin-related complications. The present investigation was undertaken to demonstrate that hydroxyapatite-coated abutments provide improved soft tissue integration compared with conventional (pure titanium) abutments and are suitable for use without surgical removal of subepidermal soft tissues. MATERIALS AND METHODS: Forty-eight implants for bone conduction with two different types of abutments (test and control) were inserted in the skull parietal part of eight sheep. Test abutments had a hydroxyapatite-coated surface and a concave shape. Conventional titanium abutments were used as controls. A follow-up time of 4 weeks was used. Histomorphometric analyses of test and control samples were analyzed, and morphometric results were compared using mixed model analysis. RESULTS: Histological assessment showed healthy soft tissues around the abutments with limited or no signs of inflammation. Hydroxyapatite-coated abutments showed intimate dermal adherence, while less close contact was noted for control abutments. Statistically significant differences in mean pocket depth (0.4 vs 1.6 mm, p = .0013) and epidermal downgrowth (0.6 vs 2.0 mm, p = .0003) between test and control abutments were recorded. CONCLUSION: The study confirms that hydroxyapatite-coated abutments resulted in a significant reduction in pocket depth and improved soft tissue integration compared with conventional titanium abutments, possibly by providing tight adherence at the interface. Statistically significant reduced pocket depth formation and epidermal downgrowth were recorded.

Orbit rehabilitation with extraoral implants: impact of radiotherapy.

PURPOSE: The aim of the study was to compare the success rates of osseointegration among irradiated and nonirradiated cases submitted to implant placement for anchorage of orbit prostheses from 2003 to 2011. MATERIALS AND METHODS: Charts of 45 consecutive patients were analyzed, 31 men and 14 women, and they were divided in two groups, considering previous irradiation therapy. Nonirradiated group had 33 patients, and irradiated group had 12 patients. In total, 138 implants were installed, 42 (30.4%) in previously irradiated bone. RESULTS: The overall implant survival rate was 96.4% with a success rate of 99.0% among the nonirradiated patients and 90.5% among the irradiated patients (p = 0.03). CONCLUSIONS: Results showed that irradiated sites had a worse prognosis related to success of osseointegration, although the 90.5% survival rate in this group indicates that implant placement is a feasible alternative to anchor orbit prostheses considering the benefits that this technique offers to patients.