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1.
Artículo en Inglés | MEDLINE | ID: mdl-32676497

RESUMEN

The use of human mesenchymal stromal cells (hMSCs) for cartilage regeneration has been hampered by the inherent donor variation of primary monolayer expanded cells. Although CD markers are typically used to characterize cell populations, there is no correlation between CD marker profile and functional outcomes. Therefore, we aimed to discover novel predictive MSC chondrogenesis markers. The chondrogenic potential of primary human bone marrow MSCs (hBMSCs) over multiple passages was assessed by standard pellet culture. We confirmed that the ratio of TGFß-RI/TGFß-RII at the time of cell recovery from the tissue culture plastic reliably predicted chondrogenic potential. Furthermore, it is possible to prospectively characterize any human BMSC cell population as responders or non-responders with respect to chondrogenic differentiation potential. Transient increase of the ratio with siRNA knockdown of TGFß-RII reproducibly recovered the chondrogenic differentiation ability of non-responsive MSCs. Together this offers an opportunity to produce a more functionally characterized cell population for use in autologous cartilage repair therapies.

2.
Biomed Res Int ; 2020: 8894471, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33860030

RESUMEN

The alveolar ridge splitting technique (ARST) offers an alternative to classic ridge augmentation techniques for successful insertion of dental implants. However, the buccal lamella is at risk of fracturing during ARST distraction. To better understand the fracture mechanisms and displacement limits of the split lamella, this study conducted biomechanical tests on human cadaveric maxilla specimens having extremely atrophied alveolar ridges treated with ARST. A total of 12 standardized alveolar splits were prepared on the maxillae of 3 elderly female donors using an oscillating piezoelectric saw. Mimicking the surgical distraction process of the lamella, each split was tested to failure using a dental osteotome attached to the crosshead of an electromechanical testing system. All specimens were scanned by means of high-resolution peripheral quantitative computed tomography prior to and post testing to evaluate split geometries and failure modes. Split stiffness, failure force, and displacement were 27.4 ± 18.7 N/mm, 12.0 ± 8.4 N, and 0.97 ± 0.31 mm, with no significant differences between anatomical sides and split locations (p ≥ 0.17). Stiffness correlated significantly with failure force (R 2 = 0.71, p < 0.01). None of the alveolar split widths correlated significantly with the outcomes from biomechanical testing (p ≥ 0.10). The results suggest that simple geometrical measures do not predict the allowed extent of lamella distraction prior to failure. More sophisticated methods are required for surgical planning to optimize the ARST outcomes. Still, the present study may advocate a clinical protocol for the maxilla where the implant site is prepared directly after osteotomy setting and immediately before full lamella dislocation, when the lamella is still stable, resistant to mechanical stress, and bone loss caused by the abrasion of the burr is minimized.


Asunto(s)
Proceso Alveolar/fisiología , Proceso Alveolar/cirugía , Aumento de la Cresta Alveolar , Maxilar/fisiología , Maxilar/cirugía , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Cadáver , Femenino , Humanos , Modelos Lineales
3.
Int J Implant Dent ; 5(1): 43, 2019 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-31776815

RESUMEN

OBJECTIVE: Impaired health conditions and related lack of adequate host healing are among the most important conditions that account for dental implant failure. Today clinicians face an increasing number of immunocompromised patients requesting implant-based rehabilitation. To provide clinical evidence for prospective decision-making, the aim of this systematic review and meta-analysis was to analyse the influence of immunodeficiency on dental implant survival. METHODS: The study was conducted according to the PRISMA Statement and the principles of the Cochrane Collaboration. MEDLINE and Web of Science were searched. Results were calculated by the pooled incidence of implant loss. Reported odds ratios (OR) from fully adjusted models were preferred. Distinct risk estimates were synthesised with 95% confidence intervals. RESULTS: A total of 62 publications including 1751 endosseous implants placed in immunocompromised patients were included. For the follow-up of 24 months and longer, the mean survival rate of implants in patients with HIV was 93.1%, chemotherapy was 98.8%, autoimmune disease was 88.75%, after organ transplantation was 100%. Crohn's disease showed a significant effect on early implant failure and resulted in increased, however not significant, implant loss. CONCLUSION: No significant effect of immunocompromised conditions on implant survival was detectable. Implant-based therapy in immunocompromised patients should not aggravate the general morbidity and must not interfere in life-saving therapies. A careful risk stratification prior implant therapy is fundamental. To further decipher the role of immunosuppression on dental implantology, more data from controlled and randomised studies are needed.

4.
Odontology ; 107(2): 269, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30721386

RESUMEN

In the Original publication of the article, the co-author has been misspelled as Fabian Duttenhöfer in the article "Treatment of stage II medication-related osteonecrosis of the jaw with necrosectomy and autologous bone marrow mesenchymal stem cells" published in October 2017, Volume 105, Issue 4 of Odontology. The correct name is "Fabian Duttenhoefer".

5.
Biomed Res Int ; 2018: 3579654, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30406133

RESUMEN

The alveolar ridge splitting technique enables reconstruction of atrophied alveolar ridges prior implantation. However, in cases of severe atrophy, there is an unpredictable risk of fracturing the buccal lamella during the expansion. Currently, there is no preoperative assessment to predict the maximum distraction of the lamella. The aim of this study was to develop a biomechanical model to mimic the alveolar ridge splitting and a finite element (FE) model to predict the experimental results. The biomechanical testing was conducted on porcine mandibles. To build the FE model high resolution peripheral quantitative computer tomography scans of one specimen was performed after the osteotomy outline, but before the lamella displacement. A servo-electric testing machine was used for the axial tension test to split the lamellae. Results showed, in line with clinical observations, that the lamellae broke primarily at the base of the splits with a median displacement of 1.27 mm. The FE model could predict fracture force and fracture displacement. Fracture force showed a nonlinear correlation with the height of the bone lamella. In conclusion, good correspondence between mechanical testing and virtual FE analysis showed a clinically relevant approach that may help to predict maximum lamella displacement to prevent fractures in the future.


Asunto(s)
Proceso Alveolar/fisiopatología , Proceso Alveolar/cirugía , Aumento de la Cresta Alveolar , Análisis de Elementos Finitos , Fracturas Óseas/fisiopatología , Fracturas Óseas/cirugía , Animales , Fenómenos Biomecánicos , Osteotomía , Sus scrofa , Tomografía Computarizada por Rayos X
6.
J Craniomaxillofac Surg ; 45(9): 1521-1525, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28807463

RESUMEN

MatrixMANDIBLE Preformed Reconstruction Plates (MMPRPs) were developed to overcome laborious bending procedures of conventional reconstruction plates. The design comprises three sizes with a nonbendable centerpiece and two bendable sections (proximal and distal). According to the surgical protocol unnecessary parts are trimmed after the last used screw hole. In the present retrospective study postoperative radiographs from 130 patients (average age 63 years) that received treatment with MMPRPs were assessed. There was no statistical correlation between plate-size, location (left/right) or age. 82.98% of the small and 91.80% of the medium MMPRPs were trimmed by at least the terminal screw hole of the ramus part. In all patients receiving a large MMPRP, the terminal screw hole of the ramus was unused accordingly all inserted large MMPRPs were trimmed by at least the terminal screw hole. The majority of the bridged defects were located within the area of the body indicating a feasible plate design. With the emergence of solid free form fabrication of Ti-alloys and economic need to reduce the waste of resources this study may help to further improve the MMPRP design and prevent the loss of medical-grade titanium.


Asunto(s)
Placas Óseas , Mandíbula/cirugía , Procedimientos Quirúrgicos Orales/instrumentación , Procedimientos de Cirugía Plástica/instrumentación , Adulto , Anciano , Anciano de 80 o más Años , Tornillos Óseos , Diseño de Equipo , Femenino , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Persona de Mediana Edad , Radiografía Dental , Estudios Retrospectivos , Titanio
7.
JMIR Res Protoc ; 6(5): e99, 2017 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-28536095

RESUMEN

BACKGROUND: Observational studies have proven to be a valuable resource in medical research, especially when performed on a large scale. Recently, mobile device-based observational studies have been discovered by an increasing number of researchers as a promising new source of information. However, the development and deployment of app-based studies is not trivial and requires profound programming skills. OBJECTIVE: The aim of this project was to develop a modular online research platform that allows researchers to create medical studies for mobile devices without extensive programming skills. METHODS: The platform approach for a modular research platform consists of three major components. A Web-based platform forms the researchers' main workplace. This platform communicates via a shared database with a platform independent mobile app. Furthermore, a separate Web-based login platform for physicians and other health care professionals is outlined and completes the concept. RESULTS: A prototype of the research platform has been developed and is currently in beta testing. Simple questionnaire studies can be created within minutes and published for testing purposes. Screenshots of an example study are provided, and the general working principle is displayed. CONCLUSIONS: In this project, we have created a basis for a novel research platform. The necessity and implications of a modular approach were displayed and an outline for future development given. International researchers are invited and encouraged to participate in this ongoing project.

9.
Biomed Res Int ; 2015: 659542, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26491682

RESUMEN

In bone tissue engineering (TE) endothelial cell-osteoblast cocultures are known to induce synergies of cell differentiation and activity. Bone marrow mononucleated cells (BMCs) are a rich source of mesenchymal stem cells (MSCs) able to develop an osteogenic phenotype. Endothelial progenitor cells (EPCs) are also present within BMC. In this study we investigate the effect of EPCs present in the BMC population on MSCs osteogenic differentiation. Human BMCs were isolated and separated into two populations. The MSC population was selected through plastic adhesion capacity. EPCs (CD34(+) and CD133(+)) were removed from the BMC population and the resulting population was named depleted MSCs. Both populations were cultured over 28 days in osteogenic medium (Dex(+)) or medium containing platelet lysate (PL). MSC population grew faster than depleted MSCs in both media, and PL containing medium accelerated the proliferation for both populations. Cell differentiation was much higher in Dex(+) medium in both cases. Real-time RT-PCR revealed upregulation of osteogenic marker genes in depleted MSCs. Higher values of ALP activity and matrix mineralization analyses confirmed these results. Our study advocates that absence of EPCs in the MSC population enables higher osteogenic gene expression and matrix mineralization and therefore may lead to advanced bone neoformation necessary for TE constructs.


Asunto(s)
Células de la Médula Ósea/metabolismo , Diferenciación Celular , Proliferación Celular , Células Endoteliales/metabolismo , Células Madre Mesenquimatosas/metabolismo , Osteogénesis , Adulto , Anciano , Anciano de 80 o más Años , Células de la Médula Ósea/citología , Adhesión Celular , Células Cultivadas , Células Endoteliales/citología , Femenino , Humanos , Masculino , Células Madre Mesenquimatosas/citología , Persona de Mediana Edad
10.
J Craniomaxillofac Surg ; 43(8): 1487-93, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26315276

RESUMEN

In oral and maxillofacial surgery, autologous grafts from the iliac crest remain the 'gold standard' for alveolar ridge reconstruction, whereas intraoral bone grafts are considered in smaller defects. To date, a comparison of the osteogenic potential of osteoblasts with regard to their tissue origin is missing. Primary osteoblasts have proven useful for the investigation of the tissue-specific osteogenic properties. The present study compares primary human alveolar (aHOBs) and iliac osteoblasts (iHOBs) derived from three female patients undergoing routine intraoral bone grafting. Proliferation potential of the osteoblasts was evaluated using real-time impedance monitoring. Relative gene expression of bone specific biomarkers was analyzed and quantified using quantitative polymerase chain reactions (qPCR). Immunohistochemistry and phase contrast microscopy were performed, as well as alkaline phosphatase assay and alizarin red staining to visualize morphology and mineralization capacity. A twofold faster proliferation rate of aHOBs compared with iHOBs (130 h vs. 80 h) was observed. Alkaline phosphatase activity and alizarin red staining in both HOBs indicated similar mineralization capacity. Gene expression of seven genes (BMP1, CSF-1, TGFBR1, ICAM1, VCAM1, SPP1 and DLX5) was significantly higher in iHOB than in aHOB samples. These data suggest a higher osteogenic potential of osteoblasts derived from the iliac crest compared with primary osteoblasts from the alveolar bone and may lead to a better understanding of the molecular impact of bone cells from different bone entities on bone regeneration in alveolar ridge reconstructions.


Asunto(s)
Proceso Alveolar/citología , Ilion/citología , Osteoblastos/fisiología , Adulto , Fosfatasa Alcalina/análisis , Biomarcadores/análisis , Proteína Morfogenética Ósea 1/genética , Regeneración Ósea/genética , Calcificación Fisiológica/fisiología , Técnicas de Cultivo de Célula , Proliferación Celular , Células Cultivadas , Impedancia Eléctrica , Femenino , Expresión Génica/genética , Proteínas de Homeodominio , Humanos , Molécula 1 de Adhesión Intercelular/genética , Factor Estimulante de Colonias de Macrófagos/genética , Persona de Mediana Edad , Osteopontina/genética , Proyectos Piloto , Proteínas Serina-Treonina Quinasas/genética , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/genética , Factores de Transcripción , Molécula 1 de Adhesión Celular Vascular/genética
11.
Macromol Biosci ; 15(8): 1035-44, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25943094

RESUMEN

BMP-2 and TGF-ß1 released from injectable thermoresponsive hydrogels are studied in the presence and absence of branched macromolecules bearing BMP-2 or TGF-ß1 affinity binding peptides. The synthesized branched macromolecules and the gelling compositions before and after loading with either BMP-2 or TGF-ß1 are characterized physico-chemically and show a significantly lower amount of proteins released in the presence of the affinity binding peptide macromolecules. This study illustrates the potential of affinity binding peptide functionalized dendrimers to modulate the local delivery and availability of growth factors important for musculoskeletal regeneration therapies.


Asunto(s)
Proteína Morfogenética Ósea 2/química , Sistemas de Liberación de Medicamentos , Ácido Hialurónico/química , Factor de Crecimiento Transformador beta1/química , Aminoácidos/química , Proteína Morfogenética Ósea 2/metabolismo , Preparaciones de Acción Retardada , Dendrímeros/química , Dendrímeros/farmacología , Humanos , Ácido Hialurónico/farmacología , Hidrogeles/química , Hidrogeles/farmacología , Espectroscopía de Resonancia Magnética , Nanotecnología , Péptidos/química , Péptidos/farmacología , Unión Proteica , Reología , Factor de Crecimiento Transformador beta1/metabolismo
12.
J Craniomaxillofac Surg ; 43(6): 758-62, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25964005

RESUMEN

BACKGROUND: A prerequisite of irradiation after advanced head and neck tumour resection is the accurate localization of the tumour resection margin. The purpose of the following study is to evaluate the use of surgical clips placed in the tumour resection margins for use as radiographic markers to facilitate focussed adjuvant radiation therapy. MATERIALS: To evaluate whether the clips remain predictive for the resection margin, we analysed the deviation of each clip in two postoperative CT scans on different days. Bone registration points were used to fuse the two CT scans in the region of the primary tumour and the distances between corresponding clips were measured. RESULTS: The tumour resection margins were labelled with an average of 18 titanium clips. In total 282 clips were evaluated. Metric analysis of clip deviation between the two postoperative CT scans found a mean distance of 4.5 mm ± 2.5 mm with a range of 0.5-11.8 mm. No significant statistical relationship of the clip differences as a function of time, the method of reconstruction or administered radiotherapy could be demonstrated. CONCLUSION: Placement of surgical clips in the cavity walls after complete tumour resection provides an easy and inexpensive approach for defining resection margins and allows for increased accuracy of adjuvant treatment. Clinical trial number DRKS00007534.


Asunto(s)
Marcadores Fiduciales , Neoplasias de Cabeza y Cuello/cirugía , Márgenes de Escisión , Instrumentos Quirúrgicos , Tomografía Computarizada por Rayos X/métodos , Materiales Biocompatibles/química , Estudios de Seguimiento , Colgajos Tisulares Libres/trasplante , Neoplasias de Cabeza y Cuello/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Disección del Cuello/métodos , Estudios Prospectivos , Radioterapia Adyuvante , Procedimientos de Cirugía Plástica/métodos , Reproducibilidad de los Resultados , Titanio/química , Técnicas de Cierre de Heridas
13.
J Craniomaxillofac Surg ; 43(5): 611-5, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25863644

RESUMEN

Long-term results of reconstructions and prosthetic rehabilitation of patients presenting severely atrophied edentulous ridges remains a challenge for clinicians. Among the various available augmentation materials there is evidence that avascular fibula bone grafts possess a reliable resistance against resorption and may thus provide a valuable source to reduce the loss of vertical bone height after reconstruction of the severely atrophied mandible and maxilla. The purpose of the present study was to assess long-term crestal bone level stability in avascular fibula bone grafts. 8 edentulous female patients (average age 70.6 years) with Class-VI-atrophy and less than 5 mm residual bone volume received onlay-grafting with avascular fibula bone grafts and were monitored with a mean observation time of 133.7 months (121-186). A total of 39 implants were placed in the maxilla and mandible. Three patients received immediate and five patients delayed implant placement 3 months after grafting. All patients were provided with bar-retained dentures. Postoperative evaluation included clinical implant success (Buser) and radiographic examinations (orthopantomogram) to quantify crestal bone resorption. Grafting was successfully performed in all patients with no regrafting necessary. All implants but one, lost 2 years after abutment connection, remained successfully integrated and fulfilled the Buser criteria, rendering to a success rate of 97%. Mean bone resorption after 10 years was mesial 1.4 mm and distal 1.4 mm at each implant-site. Maximum bone resorption occurred between postoperative and first year, thereafter no significant resorption was measured in re-examinations up to 15 years. Avascular fibula grafts are a reliable bone graft for augmentation procedures in atrophied edentulous ridges. Dental implants that integrated in the autogenous fibular bone grafts showed a stable crestal peri-implant bone level up to 15 years after implant placement.


Asunto(s)
Proceso Alveolar/patología , Aumento de la Cresta Alveolar/métodos , Trasplante Óseo/métodos , Implantes Dentales , Arcada Edéntula/cirugía , Anciano , Proceso Alveolar/diagnóstico por imagen , Atrofia , Autoinjertos/trasplante , Resorción Ósea/diagnóstico por imagen , Implantación Dental Endoósea/métodos , Prótesis Dental de Soporte Implantado , Dentaduras , Femenino , Peroné/cirugía , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Mandíbula/patología , Mandíbula/cirugía , Maxilar/patología , Maxilar/cirugía , Persona de Mediana Edad , Oseointegración/fisiología , Radiografía Panorámica , Sitio Donante de Trasplante/cirugía
14.
J Craniomaxillofac Surg ; 43(4): 567-73, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25841307

RESUMEN

Accurate localization of tumor resection borders is crucial for adjuvant radiotherapy. An improvement to adjuvant radiotherapy with the reduction of radiation doses to free flap reconstruction by virtual navigation procedures and titanium clips was evaluated. Thirty-three patients with oral cancer were prospectively included in the study. Following complete local excision of the primary tumor, resection borders were marked virtually using a navigation pointer and with titanium ligature clips. Postoperative delineation of tumor resection borders was examined. In five patients with microvascular free flap reconstruction a reduction of the radiation dose to the free flap reconstruction was achieved. The tumor resection borders in 30 patients were marked with titanium ligature clips. Surgical clip insertion was successful in 91%. We demonstrate a significant relationship between the reconstruction volume and the part of the target volume which will receive a reduced radiation dose. A cumulative dose of 60 Gy was administered to the target volume and a significant reduction of the administered radiation dose to the center of the flap could be demonstrated. We demonstrate an accurate delineation of the tumor resection margins. These improvements in tumor resection margin delineation allow for increased accuracy in adjuvant treatment and a reduction of radiation dose to the vascular free flap reconstruction.


Asunto(s)
Carcinoma de Células Escamosas/cirugía , Colgajos Tisulares Libres/trasplante , Neoplasias de la Boca/cirugía , Planificación de Atención al Paciente , Procedimientos de Cirugía Plástica/métodos , Dosificación Radioterapéutica , Radioterapia Adyuvante/métodos , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/radioterapia , Quimioradioterapia Adyuvante/métodos , Estudios de Factibilidad , Femenino , Humanos , Ligadura/instrumentación , Masculino , Microcirugia/instrumentación , Microcirugia/métodos , Persona de Mediana Edad , Neoplasias de la Boca/radioterapia , Disección del Cuello/métodos , Proyectos Piloto , Estudios Prospectivos , Radioterapia Guiada por Imagen/métodos , Radioterapia de Intensidad Modulada/métodos , Cirugía Asistida por Computador/métodos , Instrumentos Quirúrgicos , Titanio/química , Tomografía Computarizada por Rayos X/métodos , Interfaz Usuario-Computador
15.
Biomed Res Int ; 2015: 714230, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26798640

RESUMEN

INTRODUCTION: Human mesenchymal stromal cells (hMSCs) exhibit the potential to accelerate bone healing by enhanced osteogenic differentiation. Interleukin-1ß is highly expressed during fracture healing and has been demonstrated to exert a significant impact on the differentiation behaviour of hMSCs. Here, we investigate the effect of 2-hour IL-1ß stimulation on the differentiation and paracrine activity of hMSCs in coculture with osteosarcoma cells in vitro. METHODS: hMSCs from 3 donors were incubated for 2 hours with 10 ng/mL IL-1ß and subsequently cocultured with MG63-GFP cells either in control or in differentiation medium in a transwell system for 28 days. Genetic and functional effects were investigated. RESULTS: hMSCs cultured in control medium exhibited a regulatory effect on cocultured MG63-GFP cells, resulting in upregulation of osteogenic gene expression in combination with increased ALP activity. However, while stimulated hMSCs cultured under differentiation conditions exhibit signs of osteogenic differentiation, osteogenic differentiation also caused an impaired regulatory effect on the cocultured MG63-GFP cells. CONCLUSION: Short stimulation of hMSCs has the potential to modify their long-term behaviour. In addition, undifferentiated hMSCs are able to regulate osteoblast differentiation; however, this regulatory function is lost upon osteogenic differentiation in vitro. This offers a novel approach for clinical cell therapy protocols.


Asunto(s)
Diferenciación Celular/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Interleucina-1beta/farmacología , Células Madre Mesenquimatosas/metabolismo , Osteoblastos/metabolismo , Comunicación Paracrina/efectos de los fármacos , Adulto , Línea Celular Tumoral , Técnicas de Cocultivo , Medios de Cultivo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Osteogénesis/efectos de los fármacos , Osteosarcoma/metabolismo , Factores de Tiempo
16.
Clin Oral Investig ; 19(6): 1347-52, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25416636

RESUMEN

OBJECTIVES: The purpose of this study was to evaluate the long-term survival rate and potential influencing factors of dental implants and implant-retained prostheses in oral cancer patients who had undergone surgical tumor resection. MATERIAL AND METHODS: In the present study, 157 patients (95 females and 62 males with a mean age of 53.7 years) with 830 implants were included. All patients were diagnosed with a malignant tumor in the oral cavity and had undergone ablative surgery. In 55 patients (292 implants), the surgical procedure was followed by an additional radiochemotherapy (RCT) before implant placement. Nicotine users who received RCT were excluded from this study. Patients were clinically examined every 6 or 12 months according to a standard procedure. RESULTS: Of the 830 examined implants, 450 were placed in the maxilla and 380 in the mandible. A total of 65 implants were lost, 36 in the maxilla and 29 in the mandible; of these, 42 implants (65%) were documented as lost due to the patient's death. The mean observation period was 121 months. The cumulative survival rate was 94.9% at 3 years and 92.5% at 7 years. With an observation period up to 20 years, the cumulative survival rate remained constant after 11 years with 90.8%. Age, gender, and localization (maxilla/mandible) of implants did not show any influence on the survival of the implants. However, radiochemotherapy was determined as a significant factor influencing the survival rate. CONCLUSIONS: The results of this study demonstrate that the survival rate of implants was significantly lower in oral cancer patients who had been treated by ablative surgery and additional radiochemotherapy than in patients without RCT. Since there is no significant difference in the mortality rate of patients with additional RCT compared to patients who underwent sole ablative surgery, the higher loss ratio is due to a late failure of osseointegration. CLINICAL RELEVANCE: Dental implants in oral cancer patients who had been treated by ablative surgery show a high and steady cumulative survival rate after 11 years. Implant survival of patients with additional RCT is significantly lower. Non-smoking-irradiated patients seem to have a better implant survival.


Asunto(s)
Implantes Dentales , Prótesis Dental de Soporte Implantado , Fracaso de la Restauración Dental , Análisis de Falla de Equipo , Neoplasias de la Boca/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad
17.
Clin Oral Implants Res ; 26(10): 1195-202, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24893967

RESUMEN

OBJECTIVES: X-ray-based planning and post-implantation assessment of titanium implants is the commonly accepted standard to date. However, new implant materials such as zirconia (ZrO2 ) have become available, and magnetic resonance imaging may be a valuable alternative with these implants. The present in vitro study investigated artifacts produced by titanium and zirconia implants in magnetic resonance imaging (MRI) and assessed the accuracy of pre-implant planning and post-implantation assessment comparing MRI to standard X-ray-based imaging modalities: Orthopantomogram (OPT), cone beam (CBCT), and computed tomography (CT). MATERIALS AND METHODS: Twelve porcine mandibles were prepared and scanned (MRI, OPT, CBCT, µCT), and bone height above the nerve canal was measured. Specimens were implanted with either two titanium or zirconia implants and rescanned to investigate the influence of implant materials on post-implantation assessment. MRI and µCT artifacts were quantified with implants embedded in gelatin phantoms and porcine specimens. RESULTS: Compared with CBCT set as standard, µCT, OPT, and MRI showed similar accuracy in pre-op bone height measurements. Post-implantation, while titanium implants induced a strong B0 -field distortion resulting in extensive signal voids, zirconia implants were clearly depictable with only minor distortions. CONCLUSIONS: Excellent contrast, limited artifacts, radiation-free and accurate implant assessment may indicate that MRI is a valuable imaging alternative for zirconia-based implant dentistry.


Asunto(s)
Implantes Dentales , Materiales Dentales , Imagen por Resonancia Magnética/métodos , Radiografía Dental/métodos , Circonio , Animales , Artefactos , Tomografía Computarizada de Haz Cónico , Mandíbula/diagnóstico por imagen , Radiografía Panorámica , Porcinos , Titanio
18.
Oral Health Dent Manag ; 13(3): 870-6, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25284573

RESUMEN

The aim of this case series was to clinically demonstrate successful prevention of bone resorption of the buccal wall after alveolar bone splitting by additional stabilization of the lateral bone plate using a biphasic ceramic bone substitute. In three patients alveolar bone splitting was performed with a piezoelectric device. Clinical as well as radiological results after two and five years revealed stable hard and soft tissue conditions with no soft tissue recessions and peri-implant bone loss in three patients. The advantage of this one-stage procedure was the ability to insert dental implants into a very compromised bony site in a simultaneous procedure. Yet the bone splitting stabilisation technique appeared to be a more user-sensitive method.

19.
Acta Biomater ; 10(10): 4340-50, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24993802

RESUMEN

The controlled presentation of biofunctionality is of key importance for hydrogel applications in cell-based regenerative medicine. Here, a versatile approach was demonstrated to present clustered binding epitopes in an injectable, thermoresponsive hydrogel. Well-defined multivalent dendrimers bearing four integrin binding sequences and an azido moiety were covalently grafted to propargylamine-derived hyaluronic acid (Hyal-pa) using copper-catalyzed alkyne-azide cycloaddition (CuAAC), and then combined with pN-modified hyaluronan (Hyal-pN). The dendrimers were prepared by synthesizing a bifunctional diethylenetriamine pentaacetic acid core with azido and NHBoc oligo(ethylene glycol) aminoethyl branches, then further conjugated with solid-phase synthesized RGDS and DGRS peptides. Azido terminated pN was synthesized by reversible addition-fragmentation chain transfer polymerization and reacted to Hyal-pa via CuAAC. Nuclear magnetic resonance (NMR), high performance liquid chromatography, size exclusion chromatography and mass spectroscopy proved that the dendrimers had well-defined size and were disubstituted. NMR and atomic absorption analysis confirmed the hyaluronan was affixed with dendrimers or pN. Rheological measurements demonstrated that dendrimers do not influence the elastic or viscous moduli of thermoresponsive hyaluronan compositions at a relevant biological concentration. Finally, human mesenchymal stromal cells were encapsulated in the biomaterial and cultured for 21days, demonstrating the faculty of this dendrimer-modified hydrogel as a molecular toolbox for tailoring the biofunctionality of thermoresponsive hyaluronan carriers for biomedical applications.


Asunto(s)
Dendrímeros/química , Epítopos/química , Ácido Hialurónico/química , Hidrogeles/química , Células Madre Mesenquimatosas , Células Inmovilizadas/citología , Células Inmovilizadas/metabolismo , Cromatografía Líquida de Alta Presión , Dendrímeros/síntesis química , Femenino , Humanos , Hidrogeles/síntesis química , Espectroscopía de Resonancia Magnética , Masculino , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/metabolismo , Medicina Regenerativa/métodos
20.
Biores Open Access ; 3(2): 75-6, 2014 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-24804168

RESUMEN

OBJECTIVE: Clinical follow-up of implant survival in 11 patients comparing two different methods for mesenchymal stem cell (MSC) isolation (Ficoll and bone marrow aspirate concentrate [BMAC]) applied in maxillary sinus augmentation. METHODS: Mononuclear cells, including MSCs, were concentrated with either Ficoll (control group, n=6 sinus) or BMAC (test group, n=12 sinus) and transplanted in combination with bovine bone mineral. A total of 50 implants were placed in a second surgical intervention (17 Ficoll/33 BMAC) and loaded after 4 months. Overall implant survival was assessed with a Kaplan-Meier model using package survival under R. RESULTS: Implant survival of the Ficoll group was 100% compared with the BMAC group, which had 93.4% survival (95% confidence interval, 0.849-1). The difference between the groups was not significant (p=0.381). CONCLUSION: The BMAC system is an effective and suitable "chair-side" method for clinical application in hard tissue regeneration.

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