Cigarette smoke inhalation influences bone healing of post-extraction tooth socket: a histometric study in rats

The aim of this study was to evaluate, histometrically, the bone healing of the molar extraction socket just after cigarette smoke inhalation (CSI). Forty male Wistar rats were randomly assigned to a test group (animals exposed to CSI, starting 3 days before teeth extraction and maintained until sacrifice; n=20) and a control group (animals never exposed to CSI; n=20). Second mandibular molars were bilaterally extracted and the animals (n=5/group/period) were sacrificed at 3, 7, 10 and 14 days after surgery. Digital images were analyzed according to the following histometric parameters: osteoid tissue (OT), remaining area (RA), mineralized tissue (MT) and non-mineralized tissue (NMT) in the molar socket. Intergroup analysis showed no significant differences at day 3 (p>0.05) for all parameters. On the 7th day, CSI affected negatively (p<0.05) bone formation with respect to NMT and RA (MT: 36%, NMT: 53%, RA: 12%; and MT: 39%, NMT: 29%, RA: 32%, for the control and test groups, respectively). In contrast, no statistically significant differences (p>0.05) were found at days 10 and 14. It may be concluded that CSI may affect socket healing from the early events involved in the healing process, which may be critical for the amount and quality of new-bone formation in smokers.

Healing of a tooth with an overinstrumented apex, extensive transportation and periapical lesion using a 5 mm calcium hydroxide apical plug: an 8-year follow-up report

Besides the risk of filling material extrusion throughout the apex, a satisfactory apical seal can be difficult to achieve in canals with open apices or iatrogenic enlargements of the apical constriction. These situations pose a challenge to root canal filling. This paper describes the root canal filling of a maxillary right canine with an overinstrumented apex, complete loss of the apical stop, extensive canal transportation and apical periodontitis. A 5 mm calcium hydroxide apical plug was placed before root canal filling. The plug was made by soaking paper points with saline, dipping the points in calcium hydroxide powder and then applying it to the apex several times, until a consistent apical plug was obtained. The canal was then irrigated with saline in order to remove any residual calcium hydroxide from the root canal walls, dried with paper points and obturated with an inverted #80 gutta-percha cone and zinc oxide-eugenol based sealer by the lateral condensation technique. An 8-year radiographic follow-up showed formation of mineralized tissue sealing the apical foramen, apical remodeling and no signs of apical periodontitis.

The vegetal biomembrane in the healing of chronic venous ulcers

BACKGROUND: The vegetal biomembrane has been used to treat cutaneous ulcers. OBJECTIVES: To assess the role of the vegetal biomembrane on the chronic venous ulcers treatment compared to treatment with collagenase cream. METHODS: Fourteen patients were selected to be treated with vegetal biomembrane and 7 with Fibrase®(CONTROL), followed clinically and photographically by the Wound Healing Index by ImageJ during 120 days and biopsied on the 1st and 30th days for histological examination. RESULTS: The vegetal biomembrane was better in promoting healing of the ulcers, especially on the inflammatory phase, confirmed by abundant exudation and wound debridement than the CONTROL group, on the 30th day. There was a greater tendency to angiogenesis followed by re-epithelialization with highest wound healing index on the 90th and 120th days. CONCLUSION: A combined analysis of clinical and histopathological findings suggests that the vegetal biomembrane acted as a factor inducing wound healing, especially on the inflammatory phase, confirmed by abundant exudation of the lesions promoting the transformation of the microenvironment of the chronic venous ulcers, and also stimulating angiogenesis and subsequent re-epithelialization.

Topical Brazilian propolis improves corneal wound healing and inflammation in rats following alkali burns

Abstract Background The objective of this study was to investigate the effects of the Brazilian Scaptotrigona sp propolis, a widely used folk medicine, in corneal wound healing and inflammation. Methods Corneal epithelial defects of 1 mm in diameter were made in the right eyes of Wistar male adult rats by cauterization with silver nitrate sticks. Subsequently, they were divided in two groups (n = 40 rats/group): Brazilian propolis (BP) group was topically treated with a microemulsion containing 1% Brazilian propolis; vehicle (VH) group received the same formulation without propolis. The epithelial defect area was photographed and measured at t = 0 (wound induction), and after 12, 24, 48 and 120 h of treatment. The inflammatory response was evaluated based on counting of neutrophils. Epithelial regeneration rates were determined based on Ki-67 expression in basal epithelial cells. Comparisons were made using the Kruskal-Wallis and the Mann–Whitney U test. Results The BP group presented both smaller epithelial defect areas at 12, 24 and 48 h and fewer corneal infiltrating neutrophils at 24 and 48 h (P < 0.01) than the VH group. These effects were associated with more pervasive Ki-67 staining in the BP group at 12 and 24 h (P < 0.05). Conclusions Topically applied BP accelerated wound healing and reduced the inflammatory response to silver nitrate-induced corneal alkali burns in rats.

The effect of bone allografts combined with bone marrow stromal cells on the healing of segmental bone defects in a sheep model

Background: The repair of large bone defects is a major orthopedic challenge because autologous bone grafts are not available in large amounts and because harvesting is often associated with donor-site morbidity. Considering that bone marrow stromal cells (BMSC) are responsible for the maintenance of bone turnover throughout life, we investigated bone repair at a site of a critically sized segmental defect in sheep tibia treated with BMSCs loaded onto allografts. The defect was created in the mid-portion of the tibial diaphysis of eight adult sheep, and the sheep were treated with ex-vivo expanded autologous BMSCs isolated from marrow aspirates and loaded onto cortical allografts (n = 4). The treated sheep were compared with control sheep that had been treated with cell-free allografts (n = 4) obtained from donors of the same breed as the receptor sheep. Results: The healing response was monitored by radiographs monthly and by computed tomography and histology at six, ten, fourteen, and eighteen weeks after surgery. For the cell-loaded allografts, union was established more rapidly at the interface between the host bone and the allograft, and the healing process was more conspicuous. Remodeling of the allograft was complete at 18 weeks in the cell-treated animals. Histologically, the marrow cavity was reestablished, with intertrabecular spaces being filled with adipose marrow and with evidence of focal hematopoiesis. Conclusions: Allografts cellularized with AOCs (allografts of osteoprogenitor cells) can generate great clinical outcomes to noncellularized allografts to consolidate, reshape, structurally and morphologically reconstruct bone and bone marrow in a relatively short period of time. These features make this strategy very attractive for clinical use in orthopedic bioengineering

Utilization of fringe projection technique for evaluation of wound dimensions and of healing progress.

Background: The methods used for evaluating wound dimensions, especially the chronic ones, are invasive and inaccurate. The fringe projection technique with phase shift is a non-invasive, accurate and low-cost optical method. Objective: The aim is to validate the technique through the determination of dimensions of objects of known topography and with different geometries and colors to simulate the wounds and tones of skin color. Taking into account the influence of skin wound optical factors, the technique will be used to evaluate actual patients’ wound dimensions and to study its limitations in this application. Methods: Four sinusoidal fringe patterns, displaced ¼ of period each, were projected onto the objects surface. The object dimensions were obtained from the unwrapped phase map through the observation of the fringe deformations caused by the object topography and using phase shift analysis. An object with simple geometry was used for dimensional calibration and the topographic dimensions of the others were determined from it. After observing the compatibility with the data and validating the method, it was used for measuring the dimensions of real patients’ wounds. Results and Conclusions: The discrepancies between actual topography and dimensions determined with Fringe Projection Technique and for the known object were lower than 0.50 cm. The method was successful in obtaining the topography of real patient’s wounds. Objects and wounds with sharp topographies or causing shadow or reflection are difficult to be evaluated with this technique.

Low temperatures reduce skin healing in the Jacaré do Pantanal (Caiman yacare, Daudin 1802)

Studies of skin wound healing in crocodilians are necessary given the frequent occurrence of cannibalism in intensive farming systems. Air temperature affects tissue recovery because crocodilians are ectothermic. Therefore, the kinetics of skin wound healing in Caiman yacare were examined at temperatures of 33°C and 23°C. Sixteen caiman were selected and divided into two groups of eight maintained at 23°C or 33°C. The studied individuals' scars were photographed after 1, 2, 3, 7, 15 and 30 days of the experimental conditions, and samples were collected for histological processing after 3, 7, 15 and 30 days. Macroscopically, the blood clot (heterophilic granuloma) noticeably remained in place covering the wound longer for the caiman kept at 23°C. Microscopically, the temperature of 23°C slowed epidermal migration and skin repair. Comparatively, new blood vessels, labeled using von Willebrand factor (vWF) antibody staining, were more frequently found in the scars of the 33°C group. The collagen fibers in the dermis were denser in the 33°C treatment. Considering the delayed healing at 23°C, producers are recommended to keep wounded animals at 33°C, especially when tanks are cold, to enable rapid wound closure and better repair of collagen fibers because such lesions tend to compromise the use of their skin as leather.

Nanocapsules for self-healing materials

Im Rahmen dieser Arbeit wurden neue Ansätze für das Konzept der kapselbasierten Selbstheilungsmaterialien untersucht. Die Verkapselung von Selbstheilungsreagenzien in funktionellen Nanokapseln wurde dabei mittels drei verschiedener Herstellungsmethoden in Miniemulsion durchgeführt. Zunächst wurde die Synthese von Kern-Schale-Partikeln mit verkapselten Monomeren für die Ringöffnungs-Metathese-Polymerisation über freie radikalische Polymerisation in Miniemulsionstropfen beschrieben. Durch orthogonale Reaktionen wurden dabei verschiedene chemische Funktionalisierungen in die Schale eingebracht. Die Rolle des Tensides, das Verhältnis von Kernmaterial zu Monomer sowie die Variation der Lösungsmittelqualität hatte dabei einen Einfluss auf die Struktur der Kolloide. Die Heilungsreagenzien blieben auch nach der Verkapselung aktiv, was durch erfolgreich durchgeführte Selbstheilungsexperimente gezeigt werden konnte. Im zweiten Abschnitt wurde die Synthese von Silica-Nanocontainern für Selbstheilungsmaterialien über Hydrolyse und Polykondensation von Alkoxysilanen an der Grenzfläche der Miniemulsionstropfen beschrieben. Dieser Ansatz ermöglichte die effiziente Verkapselung sowohl von Monomeren als auch von Lösungen der Katalysatoren für die Metathese-Polymerisation in einem Einstufenprozess. Die Größe der Kapseln, die Dicke der Schale und der Feststoffgehalt der Dispersionen konnte dabei in einem weiten Bereich variiert werden. Anhand von erfolgreich durchgeführten Selbstheilungsreaktionen, die über Thermogravimetrie und 13C-NMR-Spektroskopie verfolgt wurden, konnte gezeigt werden, dass die Selbstheilungsreagenzien nach der Verkapselung aktiv blieben. Das dritte Konzept behandelte die Herstellung von polymeren Nanokapseln mittels Emulsions-Lösungsmittelverdampfungstechnik, welche eine milde Methode zur Verkapselung darstellt. Es wurde eine allgemeine und einfache Vorgehensweise beschrieben, in der Selbstheilungsreagenzien in polymeren Nanokapseln unter Verwendung von kommerziell erhältlichen Polymeren als Schalenmaterial verkapselt wurden. Zudem wurden Copolymere aus Styrol und verschiedenen hydrophilen Monomeren über freie radikalische Polymerisation sowie über polymeranaloge Reaktionen hergestellt. Diese statistischen Copolymere waren ebenso wie Blockcopolymere zur Herstellung von wohldefinierten Kern-Schale-Nanopartikeln mittels Emulsions-Lösungsmittelverdampfungsprozess geeignet. rnrnDes Weiteren wurde ein neues Konzept für die Synthese von pH-responsiven Nanokapseln aus tensidfreien Emulsionen unter Verwendung von Copolymeren aus Styrol und Trimethylsilylmethacrylat beschrieben. Der vorgeschlagene synthetische Ansatz ermöglicht dabei die erste Synthese von Nanokapseln über den Emulsions-Lösungsmittelverdampfungsprozess in Abwesenheit eines Tensides. Eine vollständig reversible Aggregation ermöglichte eine leichte Trennung der Nanokapseln von der kontinuierlichen Phase sowie eine Erhöhung der Konzentration der Nanokapseldispersionen auf das bis zu fünffache. Darüber hinaus war es möglich, Selbstheilungsreagenzien in stabilem Zustand zu verkapseln. Abschließend wurde die elektrochemische Abscheidung von mit Monomer gefüllten Nanokapseln in eine Zinkschicht zur Anwendung im Korrosionsschutz behandelt.

Stimuli-responsive materials for self-healing in corrosion protection

The corrosion of metallic materials is a crucial issue on an economical and ecological scale. Corrosion protection becomes then necessarily needed. The main focus of the thesis is to develop stimuli-responsive nanocontainers for self-healing in corrosion protection. A nanocontainer is efficient if distinct payloads can be selectively released via different stimuli because unwanted and unspecific release can be avoided. For anti-corrosion, the wanted nanocontainer is the one able to release its self-healing agents or corrosion inhibitors upon change of pH- or/and redox-potential due to the variation of these two signals at the corroded sites. Conducting polymers such as polyaniline (PANI) were chosen for building the shell of capsules due to their important characteristics of being both pH- and redox responsive.

ChronOS Inject in Children with Benign Bone Lesions – Does It Increase the Healing Rate?

Benign bone lesions in children although rare, can result in a pathological fracture. Although their etiology and pathogenesis are not yet entirely clear, the phenomenon of spontaneous healing is well known. Nevertheless, some benign bone lesions are unlikely to heal spontaneously due to the patient's age or high risk of fracture and deformity due to the lesion's location or size. The following study presents our results after treatment of these bone cysts with chronOS Inject.

Bone marrow-derived cells in palatal wound healing

OBJECTIVE: Myofibroblasts are responsible for contraction and scarring after cleft palate repair. This leads to growth disturbances in the upper jaw. We hypothesized that cells from the bone marrow are recruited to palatal wounds and differentiate into myofibroblasts. METHODS: We transplanted bone marrow from green fluorescent protein (GFP)-transgenic rats into lethally irradiated wild-type rats. After recovery, experimental wounds were made in the palatal mucoperiosteum, and harvested 2 weeks later. GFP-expressing cells were identified using immunostaining. Myofibroblasts, activated fibroblasts, endothelial cells, and myeloid cells were quantified with specific markers. RESULTS: After transplantation, 89 ± 8.9% of mononuclear cells in the blood expressed the GFP and about 50% of adherent cells in the bone marrow. Tissue obtained during initial wounding contained only minor numbers of GFP-positive cells, like adjacent control tissue. Following wound healing, 8.1 ± 5.1% of all cells in the wound area were positive, and 5.0 ± 4.0% of the myofibroblasts, which was significantly higher than in adjacent tissue. Similar percentages were found for activated fibroblasts and endothelial cells, but for myeloid cells it was considerably higher (22 ± 9%). CONCLUSIONS: Bone marrow-derived cells contribute to palatal wound healing, but are not the main source of myofibroblasts. In small wounds, the local precursor cells are probably sufficient to replenish the defect.

Early loading after 21 days of healing of nonsubmerged titanium implants with a chemically modified sandblasted and acid-etched surface: two-year results of a prospective two-center study

PURPOSE: The aim of this two-center study was to evaluate screw-type titanium implants with a chemically modified, sandblasted and acid-etched surface when placed in the posterior maxilla or mandible, and loaded 21 days after placement. MATERIAL AND METHODS: All 56 patients met strict inclusion criteria and provided informed consent. Each patient displayed either a single-tooth gap, an extended edentulous space, or a distal extension situation in the posterior mandible or maxilla. Eighty-nine dental implants (SLActive, Institut Straumann AG, Basel, Switzerland) were inserted according to an established nonsubmerged protocol and underwent undisturbed healing for a period of 21 days. Where appropriate, the implants were loaded after 21 days of healing with provisional restorations in full occlusion. Definitive metal ceramic restorations were fabricated and positioned on each implant after 6 months of healing. Clinical measurements regarding soft tissue parameters and radiographs were obtained at different time points up to 24 months after implant placement. RESULTS: Of the 89 inserted implants, two (2.2%) implants failed to integrate and were removed during healing, and two (2.2%) additional implants required a prolonged healing time. A total of 85 (95.6%) implants were therefore loaded without incident after 21 days of healing. No additional implant was lost throughout the study period, whereas one implant was lost to follow-up and therefore left unaccounted for further analysis. The remaining 86 implants all exhibited favorable radiographic and clinical findings. Based on strict success criteria, these implants were considered successfully integrated 2 years after insertion, resulting in a 2-year success rate of 97.7%. CONCLUSION: The results of this prospective two-center study demonstrate that titanium implants with a modified SLA surface can predictably achieve successful tissue integration when loaded in full occlusion 21 days after placement. Integration could be maintained without incident for at least 2 years of follow-up.