Use of autologous tooth-derived material as a graft in the post-extraction socket. Split-mouth study with radiological and histological analysis.

BACKGROUND: The healing process after tooth removal involves bone remodelling which implies some loss of alveolar bone volume. Among materials proposed for minimising this remodelling and preserving the bone, autologous dental tissue is a promising option, but more data are needed. In this context, we evaluated size and density changes using cone beam computed tomography in autologous dental material (ADM)-preserved sockets compared to controls, and assessed biological responses by histological analysis. METHODS: A split-mouth study was conducted including 22 patients, who underwent removal of ≥ 2 single-rooted teeth with intact sockets, assigning one socket to the experimental group which received ADM for alveolar preservation and another to the control group, which only underwent blood clot stabilisation. Cone beam computed tomography was performed postoperatively (week 0) and at weeks 8 and 16 to assess socket size and bone density. Histological analysis was carried out on trephine biopsies taken (Ø4 × 4.5 mm) from the experimental group. RESULTS: Less horizontal shrinkage was observed in the ADM group, especially at week 16 considering the group-by-time interaction for the following variables: difference in height between the lingual and buccal alveolar crests (-1.00; p < .01; 95% CI: -0.28 - -1.73), and half-widths, measured as the distance from the long axis of the missing tooth to the buccal alveolar crest at 1 mm (-0.61; p < .01; 95% CI: -0.18 - -1.04) and at 3 mm (-0.56; p < .01; 95% CI: -0.15 - -0.97) below the crest, with mean decreases of 1.07 and 2.14 mm in height difference, 0.66 and 1.32 mm in half-width at 1 mm and 0.43 and 1.02 mm in half-width at 3 mm in ADM and control groups respectively. Densitometry analysis showed higher bone densities in Hounsfield units in the ADM group considering all factors analysed regardless of time point and socket third (coronal, middle, or apical). Histologically, there were no signs of inflammation or foreign body reaction, and dentin particles were surrounded by and in close contact with bone tissue. CONCLUSION: These results add to the evidence that dentin can be used successfully as a material for alveolar socket preservation, given its desirable mechanical and biological properties, and warrant larger studies.

NF-κB Decoy Oligodeoxynucleotide-Loaded Poly Lactic-co-glycolic Acid Nanospheres Facilitate Socket Healing in Orthodontic Tooth Movement.

Orthodontic space closure following tooth extraction is often hindered by alveolar bone deficiency. This study investigates the therapeutic use of nuclear factor-kappa B (NF-κB) decoy oligodeoxynucleotides loaded with polylactic-co-glycolic acid nanospheres (PLGA-NfDs) to mitigate alveolar bone loss during orthodontic tooth movement (OTM) following the bilateral extraction of maxillary first molars in a controlled experiment involving forty rats of OTM model with ethics approved. The decreased tendency of the OTM distance and inclination angle with increased bone volume and improved trabecular bone structure indicated minimized alveolar bone destruction. Reverse transcription-quantitative polymerase chain reaction and histomorphometric analysis demonstrated the suppression of inflammation and bone resorption by downregulating the expression of tartrate-resistant acid phosphatase, tumor necrosis factor-α, interleukin-1ß, cathepsin K, NF-κB p65, and receptor activator of NF-κB ligand while provoking periodontal regeneration by upregulating the expression of alkaline phosphatase, transforming growth factor-ß1, osteopontin, and fibroblast growth factor-2. Importantly, relative gene expression over the maxillary second molar compression side in proximity to the alveolus highlighted the pharmacological effect of intra-socket PLGA-NfD administration, as evidenced by elevated osteocalcin expression, indicative of enhanced osteocytogenesis. These findings emphasize that locally administered PLGA-NfD serves as an effective inflammatory suppressor and yields periodontal regenerative responses following tooth extraction.

Detection of senescent cells in the mucosal healing process on type 2 diabetic rats after tooth extraction for biomaterial development.

The delayed mucosal healing of tooth extraction sockets in diabetes has few known effective treatment strategies, and its underlying mechanism remains unknown. Senescent cells may play a pivotal role in this delay, given the well-established association between diabetes, senescent cells, and wound healing. Here, we demonstrated an increase in p21- or p16-positive senescent cells in the epithelial and connective tissues of extraction sockets in type 2 diabetic rats compared to those in control rats. Between 7 and 14 days after tooth extraction, a decrease in senescent cells and improvement in re-epithelialization failure were observed in the epithelium, while an increase in senescent cells and persistence of inflammation were observed in the connective tissue. These results suggest that cellular senescence may have been induced by diabetes and contributed to delayed mucosal healing by suppressing re-epithelization and persistent inflammation. These findings provide new targets for treatment using biomaterials, cells, and drugs.

Evaluation of 4 and 8 Weeks of Healing in a Murine Implant Model.

Dental implants are increasing in prevalence as desirable options for replacing missing teeth. Unfortunately, implants come with complications, and animal models are crucial to studying the pathophysiology of complications. Current murine model experiments can be lengthy, with 8 weeks of extraction socket healing before implant placement. Therefore, we aimed to investigate the efficacy of decreasing extraction healing time from 8 to 4 weeks in a dental implant mouse model. Thirty-one 3-week-old C57BL/6J male mice underwent maxillary first and second molar extractions followed by 8 (control) or 4 (test) weeks of extraction socket healing before implant placement. Mice were euthanized after 4 weeks of implant osseointegration. Samples were analyzed via microcomputerized tomography and histology. When mice received implants 4 weeks after extractions, there was no statistical difference in initial bone crest remodeling or surrounding bone volume compared to those after 8 weeks of healing. Histologically, the hard and soft tissues surrounding both groups of implants displayed similar alveolar bone levels, inflammatory infiltrate, osteoclast count, and collagen organization. A 4-week extraction healing period can be utilized without concern for osseointegration in a murine implant model and is a viable experimental alternative to the previous eight weeks of healing. While small animal implant models are less directly applicable to humans, advancements in experimental methods will ultimately benefit patients receiving dental implants through improved prevention and treatment of complications. Subsequent research could investigate occlusal effects or whether healing time affects prognosis after induction of peri-implantitis.

Histological Evaluation of Alveolar Ridge Preservation Using Different Bone Grafts: Clinical Study Analysis Part II.

To compare histologically the percentage of bone formation 12-20 weeks after ridge augmentation using 2 different techniques. Tooth loss is associated with 3-dimensional bone remodeling and ridge atrophy. Ridge preservation procedures can prevent alveolar bone volume loss. Different techniques and materials are used to preserve the alveolar ridge. Computer-generated randomization software was used to assign 2 ridge preservation techniques for 11 extraction sites. In group I, type I bovine Achilles tendon collagen plugs with bioactive resorbable calcium apatite crystals (CPCAC) were placed, and in group II, cortico-cancellous bone chips (CCBC) mix and an expanded polytetrafluoroethylene (ePTFE) barrier membrane were placed. The histomorphometric studies were performed using a computer-based image analysis system (ImageJ 1.4, National Institute of Health, Bethesda, Md) to calculate the pixel area of bone tissue and the remaining bone graft material. The histomorphometric data were analyzed using a Student t test to compare the measurements between the 2 experimental groups. This parametric statistical test was employed to determine if there were any statistically significant differences in the quantitative histological parameters between the groups. The sockets that received CPCAC showed a lower (31.89%) percentage of native bone surface area compared with the CCBC group (43.87%). However, the difference was not statistically significant (P < .05). In addition, the CPCAC group showed evidence of foreign-body reaction. The CCBC graft covered with an ePTFE barrier may induce more bone formation with minimal inflammation in an extraction socket compared with a collagen plug with calcium apatite crystals. In addition, histological analysis of the CPCAC graft showed evidence of foreign-body reaction, which indicates a negative clinical impact.

A radiographic and histological study to compare red (650 nm) versus near infrared (810 nm) diode lasers photobiomodulation for alveolar socket preservation.

Previous findings indicated that the laser photobiomodulation is more effective than the control or placebo in preserving the alveolar socket. This study aimed to compare two different lasers regarding their effectiveness in aiding alveolar socket preservation. Twenty extraction sockets were selected then divided into two equal groups. Group A was exposed to 650 nm Diode laser, and Group B to 810 nm Diode laser following the same protocol and parameters after a standard alveolar socket preservation procedure with collagen plug. Radiographic analysis with cone beam computed tomography was done to compare the alveolar bone surface area immediately after extraction and three months post-operatively, while bone samples collected before implant drilling were histologically examined for newly formed bone evaluation and histomorphometric analysis in terms of percentage of new bone surface area, percentage of unmineralized bone and finally, immunohistochemical analysis of Osteocalcin reaction surface area as well as optical density. Radiographically, infrared (810 nm) Diode effect on alveolar bone surface area has significantly exceeded the red laser, while histologically, red (650 nm) Diode has demonstrated statistical significance regarding all parameters; newly formed bone surface area percentage, unmineralized bone area percentage and finally Osteocalcin bone marker reaction surface area percentage and optical density. Under the specified conditions and laser parameters, photobiomodulation using the 810 nm Diode got the upper hand radiographically, yet histologically, the red 650 nm Diode managed to dominate all histological parameters when both employed as an adjunct to alveolar socket preservation procedures.

Regeneration of alveolar bone defects in the experimental pig model: A systematic review and meta-analysis.

OBJECTIVE: Pigs are emerging as a preferred experimental in vivo model for bone regeneration. The study objective was to answer the focused PEO question: in the pig model (P), what is the capacity of experimental alveolar bone defects (E) for spontaneous regeneration in terms of new bone formation (O)? METHODS: Following PRISMA guidelines, electronic databases were searched for studies reporting experimental bone defects or extraction socket healing in the maxillae or mandibles of pigs. The main inclusion criteria were the presence of a control group of untreated defects/sockets and the assessment of regeneration via 3D tomography [radiographic defect fill (RDF)] or 2D histomorphometry [new bone formation (NBF)]. Random effects meta-analyses were performed for the outcomes RDF and NBF. RESULTS: Overall, 45 studies were included reporting on alveolar bone defects or extraction sockets, most frequently in the mandibles of minipigs. Based on morphology, defects were broadly classified as 'box-defects' (BD) or 'cylinder-defects' (CD) with a wide range of healing times (10 days to 52 weeks). Meta-analyses revealed pooled estimates (with 95% confidence intervals) of 50% RDF (36.87%-63.15%) and 43.74% NBF (30.47%-57%) in BD, and 44% RDF (16.48%-71.61%) and 39.67% NBF (31.53%-47.81%) in CD, which were similar to estimates of socket-healing [48.74% RDF (40.35%-57.13%) and 38.73% NBF (28.57%-48.89%)]. Heterogeneity in the meta-analysis was high (I2 > 90%). CONCLUSION: A substantial body of literature revealed a high capacity for spontaneous regeneration in experimental alveolar bone defects of (mini)pigs, which should be considered in future studies of bone regeneration in this animal model.

Histologic wound healing in studies using different ridge preservation protocols: A review.

BACKGROUND: Alveolar ridge preservation (ARP) procedures are designed to lessen dimensional changes in the alveolar ridge after tooth extraction. Wound healing after ridge preservation involves the formation of new vital bone in the former socket, and this vital bone is important in the osseointegration of dental implants. METHODS: A series of ARP studies have been performed to help clinicians better understand the wound-healing events that occur following tooth extraction and ridge preservation. Different protocols have been examined using various materials and periods of healing time prior to implant placement. The primary aim of these studies was to ascertain the relative percentage of vital bone formation, residual graft material, and connective tissue (CT)/other at the healing site using histomorphometric examination of bone core biopsies obtained during osteotomy preparation. RESULTS: For allografts, the use of demineralized bone alone or in combination with mineralized is associated with more vital bone formation than the use of mineralized allograft alone. For mineralized allografts, the use of cortical versus cancellous bone has only minimal impact on new bone formation. Xenografts from bovine and porcine sources appear to have similar vital bone formation. Longer healing times prior to implant placement are associated with increased vital bone formation and decreased residual graft material. The most stable component in most studies is the percentage of CT/other. CONCLUSIONS: The percentage of vital bone and residual graft at ARP sites is dependent on the materials used and the length of healing time prior to obtaining core biopsies. KEY POINTS: What factors may affect the amount of new bone at the ARP site? At a time point about 4 months after ARP, the type of graft material used for ARP plays a large role in new bone formation. Studies focus on means and standard deviations, but patients often do not "follow the mean." Even if a single ARP protocol is used for all patients, there is great interindividual variability in new bone formation, and there is often variability between sites within a single patient. How long after ARP with an allograft should I wait to place an implant? Longer healing times such as 4-5 months generally provide higher amounts of vital bone formation than shorter healing times like 2-3 months. Differences in vital bone formation between ARP protocols tend to decrease with longer healing time. FDBA that contains demineralized bone, either alone or combined with mineralized FDBA, often provides higher amounts of new bone formation than 100% mineralized allograft, especially at shorter healing periods. Even a year after ARP with an allograft, residual graft material is often still present at the ARP site.

Alveolar ridge preservation of two-wall bone defects using mineralized dentin matrix: An experimental pre-clinical study.

OBJECTIVES: To study bone healing of two-wall bone defects after alveolar ridge preservation using mineralized dentin matrix. MATERIALS AND METHODS: After distal roots extraction of second and fourth premolars (P2, P4) on one lateral mandible in 12 beagles, two-wall bone defects (5 × 5 × 5 mm) were surgically created distally to the remaining mesial roots of P2 and P4. A total of 24 sites were randomly allocated to three groups (implant material- time of execution): mineralized dentin matrix (MDM)-3 m (MDM + collagen membrane; 3 months), MDM-6 m (MDM particles + collagen membrane; 6 months), and C-6 m (collagen membrane only; 6 months). Clinical, radiographic, digital, and histological examinations were performed 3 and 6 months after surgery. RESULTS: The bone healing in MDM groups were better compared to Control group (volume of bone regenerated in total: 25.12 mm3 vs. 13.30 mm3, p = .046; trabecular volume/total volume: 58.84% vs. 39.18%, p = .001; new bone formation rate: 44.13% vs. 31.88%, p = .047). Vertically, the radiological bone level of bone defect in MDM-6 m group was higher than that in C-6 m group (vertical height of bone defect: 1.55 mm vs. 2.74 mm, p = .018). Horizontally, no significant differences in buccolingual bone width were found between MDM and C groups at any time or at any level below the alveolar ridge. The percentages of remaining MDM were <1% in both MDM-3 m and MDM-6 m groups. CONCLUSIONS: MDM improved bone healing of two-wall bone defects and might be considered as a socket fill material used following tooth extraction.

Recombinant bone matrix maintains the graft space, induces vascularized bone regeneration and preserves canine tooth extraction socket structure.

AIM: Recombinant bone matrix (RBM) is a newly conceived and engineered porous bone graft granule of average size 600 µm composed of purified recombinant collagen peptide. We sought to examine the behaviour with time of RBM that was grafted in the canine tooth extraction socket. MATERIALS AND METHODS: The canine tooth extraction socket of the hemisectioned mandibular third premolar distal root was grafted with RBM granules, whereas the opposite side extraction socket served as non-grafted control. The mandibular samples were harvested at 1, 3 and 6 months of healing and subjected to micro-CT imaging and decalcified paraffin-embedded histology. Separately, the effect of RBM was compared with that of deproteinized cancellous bovine bone (DCBB) and bovine atelocollagen plug (BACP) in the canine tooth extraction model at 3 months of healing. RESULTS: RBM maintained the grafted space in the socket and the gingival connective tissue until new bone was formed within its porous space. The regenerated bone was highly vascularized and continued to mature, while RBM was completely bioresorbed by 6 months. The buccal and lingual alveolar ridge heights of the RBM-grafted extraction socket was better preserved than those of non-grafted control sockets. The degree of socket preservation by RBM was equivalent to that by DCBB, although their healing mechanisms were different. CONCLUSIONS: This study demonstrated that RBM induced controlled active bone regeneration and preserved the extraction socket structure in a canine model. Bioresorbable RBM engineered without animal or human source materials presents a novel bone graft category with robust bone regenerative property.

Avaliação tomográfica e histomorfométrica do uso da fibrina rica em plaquetas e leucócitos na cicatrização alveolar após extração dentária: um ensaio clínico randomizado / Tomographic and histomorphometric evaluation of socket healing after tooth extraction using leukocyte- and platelet-rich fibrin: a randomized, single-blind, controlled clinical trial

O uso dos concentrados plaquetários tem sido amplamente estudado em procedimentos cirúrgicos bucais. Entretanto ensaios clínicos randomizados com avaliação histomorfométrica e baixo risco de viés não são encontrados na literatura. Um ensaio clínico randomizado, controlado, cegado e paralelo foi conduzido para avaliar a eficácia da fibrina rica em plaquetas e leucócitos (L-PRF) na preservação alveolar após extrações dentárias. Adicionalmente, o efeito do L-PRF na formação óssea foi avaliado através de análises histomorfométricas. Espécimes de biópsias foram obtidos durante a cirurgia de instalação dos implantes dentários, três meses após a exodontia. Quarenta e oito pacientes com necessidade de exodontia de um elemento dentário, incluíndo pré-molares, caninos ou incisivos, foram aleatoriamente alocados em dois grupos, L-PRF (n=24) e controle (n=24). A análise por intenção de tratamento dos dados tomográficos revelou que o L-PRF reduziu a perda óssea horizontal 1mm e 3 mm abaixo da crista óssea alveolar. A perda óssea 1mm abaixo da crista foi de 0.93 ± 0.9 mm para o grupo do L-PRF e 2.27 ± 1.2 mm para o grupo controle (p=0.0001). A perda óssea 3mm abaixo da crista foi 0.85 ± 0.8 mm para o grupo L-PRF e 1.67 ± 1.1 mm para o grupo controle (p=0.005). Similarmente, o L-PRF reduziu a perda óssea vertical da tábua vestibular no grupo L-PRF, 0.70 ± 0.7 mm comparado ao grupo controle 1.39 ± 1.2 mm (p=0.02). A neoformação óssea volumétrica medida através de análise tomográfica foi significantemente maior no grupo L-PRF 190.90 ± 169.90mm3 comparada com o grupo controle 44.87 ± 200.20mm3 (p=0.009). A análise por intenção de tratamento dos dados histomorfométricos mostrou uma maior porcentagem de osso neoformado no grupo L-PRF comparado com o grupo controle, 55.96 ± 11.97% e 39.69 ± 11.13%, respectivamente (p=0.00001). Estes resultados indicam que o uso de L-PRF reduziu a reabsorção óssea alveolar após a extração dentária, e melhorou a qualidade do osso neoformado. Portanto devemos sempre considerar o uso de L-PRF quando a preservação alveolar estiver sendo planejada. (Clinicaltrials.gov NCT03408418)(AU)

The use of platelet concentrate in alveolar ridge preservation has been broadly studied in oral surgical procedures. However, no randomized clinical trial with histomorphometric analysis and low risk of bias are available in the literature. We conducted a prospective, single-blind, parallel, randomized, controlled clinical trial to evaluate the efficacy of leukocyte- and platelet-rich fibrin (L-PRF) in socket preservation after tooth extraction. Additionally, the effect of L-PRF on bone formation was analyzed histologically using bone biopsy specimens obtained during implant placement. A total of 48 subjects who underwent a non-molar tooth extraction were randomly assigned to the L-PRF group (n=24) or the control group (n=24). Cone-beam computed tomographies were performed immediately after tooth extraction and at 3 months after tooth extraction, prior to implant surgery. The intention-to-treat analysis of data from tomographies showed that L-PRF reduced horizontal bone loss at 1 mm below the alveolar crest, means of 0.93 ± 0.9 mm for the L-PRF group and 2.27 ± 1.2 mm for the control group (p=0.0001), and at 3 mm below the alveolar crest, means of 0.85 ± 0.8 mm for the L-PRF group and 1.67 ± 1.1 mm for the control group (p=0.005). Similarly, L-PRF reduced vertical bone loss at the buccal bone wall, means of 0.70 ± 0.7 mm for the L-PRF group and 1.39 ± 1.2 mm for the control group (p=0.02). The mean value of new bone formation in the L-PRF group (190.90 ± 169.90mm3) was significantly higher when compared with the control group (44.87 ± 200.20mm3) p=0.009. Histomorphometric analysis showed a higher percentage of new bone formation in the L-PRF group compared with the control group. The values were 55.96 ± 11.97% and 39.69 ± 11.13%, respectively (p=0.00001). These findings indicate that the administration of L-PRF reduce the bone resorption after tooth extraction and improve the new bone formation. Therefore it should always be considered when socket preservation is planned (Clinicaltrials. gov NCT03408418)(AU)

Evaluation of the effect of platelet-rich plasma on alveolar wound healing in rats / Evaluación del efecto del plasma rico en plaquetas en la cicatrización de heridas alveolares en ratas

Opinions about the clinical utility of platelet-rich plasma (PRP) vary, as a large number of experimental studies have questioned its efficacy. The purpose of this study was to evaluate the effects of PRP on experimental alveolar wound healing in rats. Fifty young adult male Wistar rats were divided in control and PRP groups and submitted to extraction of the right maxillary incisor. In the PRP group, blood was collected by cardiac puncture, and the socket was filled with a PRP gel. Animals were euthanized after 1, 3, 7, 14 and 30 days. Histological and histomorphometric analyses were performed at each experimental time point. Semiquantitative histological analysis showed that the PRP group exhibited significantly more collagen-matrix deposition and less bone-matrix formation in the socket than did the control group from 7 to 30 days. Histomorphometric analyses showed that the PRP group also exhibited lower bone-tissue areas than the control group at 7 (p=0.0250) and 14 days (p<0.0001), but at 30 days, no significant difference between the groups was observed. In the present study, PRP did not enhance alveolar wound healing, and PRP-treated rats exhibited low rates of bone deposition during the intermediate phases of alveolar socket repair.

Las opiniones sobre la utilidad clínica del plasma rico en plaquetas (PRP) varían, ya que un gran número de estudios experimentales han cuestionado su eficacia. El propósito de este estudio fue evaluar los efectos del PRP sobre la cicatrización experimental de heridas alveolares en ratas. Cincuenta ratas Wistar adultas fueron divididas en grupos control y PRP, y fueron sometidas a extracción del incisivo maxilar derecho. En el grupo de PRP, la sangre se recogió por punción cardiaca, y el alvéolo se llenó con un gel de PRP. Los animales se sacrificaron después de 1, 3, 7, 14 y 30 días. Se realizaron análisis histológicos e histomorfométricos en cada momento experimental. El análisis histológico semicuantitativo mostró que el grupo de PRP exhibió significativamente más deposición de matriz de colágeno y menos formación de matriz ósea en el receptáculo que el grupo control de 7 a 30 días. Los análisis histomorfométricos mostraron que el grupo PRP también exhibió áreas de tejido óseo inferiores al grupo control a 7 (p = 0,0250) y 14 días (p <0,0001), pero a los 30 días no se observó diferencia significativa entre los grupos. En el presente estudio, el PRP no mejoró la cicatrización de las heridas alveolares, y las ratas tratadas con PRP mostraron bajas tasas de deposición ósea durante las fases intermedias de la reparación de los receptáculos alveolares.

Experimental osteonecrosis: development of a model in rodents administered alendronate

Abstract The main objective of this study was to cause bisphosphonate-related osteonecrosis of the jaws to develop in a rodent model. Adult male Holtzman rats were assigned to one of two experimental groups to receive alendronate (AL; 1 mg/kg/week; n = 6) or saline solution (CTL; n = 6). After 60 days of drug therapy, all animals were subjected to first lower molar extraction, and 28 days later, animals were euthanized. All rats treated with alendronate developed osteonecrosis, presenting as ulcers and necrotic bone, associated with a significant infection process, especially at the inter-alveolar septum area and crestal regions. The degree of vascularization, the levels of C-telopeptide cross-linked collagen type I and bone-specific alkaline phosphatase, as well as the bone volume were significantly reduced in these animals. Furthermore, on radiographic analysis, animals treated with alendronate presented evident sclerosis of the lamina dura of the lower first molar alveolar socket associated with decreased radiographic density in this area. These findings indicate that the protocol developed in the present study opens new perspectives and could be a good starting model for future property design.

Alveolar ridge conservation by early bone formation after tooth extraction in rabbits: a histomorphological study / Conservación de la cresta alveolar por formación ósea temprana después de la extracción dentaria en conejos: un estudio histomorfológico

Alveolar ridge volume loss is an irreversible process. To prevent this physiological event, which typically result in significant local anatomical changes in both the horizontal and the vertical dimension, some strategies are indicated to minimize the loss of ridge volume that typically follows tooth extraction. The purpose of this study was to evaluate if three different bone grafts could promote new bone formation in the alveolar socket following tooth extraction for the alveolar ridge conservation. First mandibular molars of male adults rabbits were extracted and the extraction sockets were randomly treated with three different bone grafts, one xenograft and two alloplastic grafts, and a group that received no treatment (blood clot). The extraction sockets of selected rabbits from each group were evaluated at 4, 6, or 8-week post-extraction. The results indicated that the extraction sockets treated with alloplastic graft (biphasic calcium phosphate) exhibited lamellar bone formation (6.5%) as early as four weeks after the extraction was performed. Moreover, the degree of new bone formation was significantly higher (P<0.05) in the extraction sockets treated with biphasic calcium phosphate at 8-week post-extraction than that in the other study groups. In this study, we demonstrated that the proposed animal model is useful to evaluate the bone formation after tooth extraction and the alveolar ridge conservation is feasible. The new bone formation and alveolar ridge preservation with bone graft after extraction of molar teeth, could result in the maintenance of sufficient bone volume to place an implant in an ideal restorative position without the need for ancillary implant site development procedures.

La pérdida de volumen cresta alveolar, es un proceso irreversible. Para evitar este evento fisiológico, que típicamente resulta en cambios anatómicos locales significativos, tanto en la dimensión horizontal y vertical, existen algunos procedimienos para reducir al mínimo la pérdida de volumen óseo que sigue típicamente a la extracción del diente. El propósito de este estudio fue evaluar si tres injertos óseos diferentes podrían promover la formación de hueso en el alveolo tras la extracción del diente para la conservación de la cresta alveolar. Los primeros molares mandibulares de conejos machos adultos fueron extraídos y los alvéolos post extracción fueron rellenados aleatoriamente con tres injertos óseos diferentes, uno de xenoinjerto y dos injertos aloplásticos, más un grupo que no recibió tratamiento (coágulo de sangre). Los alvéolos post extracción en los conejos seleccionados de cada grupo fueron evaluados a las 4, 6, o 8 semanas post-extracción. Los resultados indicaron que los alvéolos tratados con injerto aloplástico mostraron formación de hueso lamelar (6,5%) ya a las 4 semanas post extracción. Por otra parte, el grado de formación de hueso nuevo fue significativamente mayor (P<0,05) en los alvéolos tratados con fosfato de calcio bifásico en 8 semanas post-extracción que en los otros grupos de estudio. Demostramos que el modelo animal propuesto es útil para evaluar la formación de hueso después de la extracción del diente, y la conservación de la cresta alveolar es factible. La nueva formación de hueso y la preservación del reborde alveolar con injerto óseo después de la extracción de los dientes molares, podrían mantener un volumen de hueso suficiente para colocar un implante en una posición ideal para la posterior restauración, sin la necesidad de procedimientos de quirúrgicos anexos.

Manejo del traumatismo alvéolo-dentario infantil en el Servicio de Urgencias de un hospital terciario / Management of pediatric dental injury in the Emergency Department of a tertiary hospital

Introducción: el traumatismo alvéolo-dentario es muy frecuente en la infancia y supone un motivo habitual de consulta en los Servicios de Urgencias pediátricos. Objetivo: estudiar el manejo de los traumatismos dentales en un hospital terciario. Material y métodos: estudio descriptivo retrospectivo. Se incluyeron todos los menores de 15 años que consultaron por traumatismo dental en la Urgencia Pediátrica del Hospital 12 de Octubre (Madrid, España) entre septiembre de 2008 y agosto de 2010. Durante este periodo se puso en marcha un protocolo de manejo de estos pacientes en nuestro centro. Resultados: en el periodo de estudio fueron atendidos 374 pacientes, el 63% varones, con una media de edad de 4,45 años. En el 84% de los casos, la etiología fue casual, seguido de un 3% relacionado con accidentes deportivos. El 32% de los pacientes fue derivado desde otros centros para valoración por Cirugía Maxilofacial. El 60% fue atendido exclusivamente por pediatras. Las causas más frecuentes de atención por parte de Cirugía Maxilofacial fueron: sutura de laceración gingival (6,4%), extracción dental (3%) y ferulización (1,3%). El 83,4% requirió solamente tratamiento médico. Conclusiones: el trauma dental es una causa frecuente de consulta en los Servicios de Urgencias y de derivación a hospitales de referencia. La mayoría de los pacientes presenta lesiones menores que no precisan la realización de pruebas complementarias ni requieren tratamiento quirúrgico, y pueden ser manejadas por un pediatra siguiendo protocolos consensuados con especialistas en Cirugía Maxilofacial (AU)

Introduction: dental injury is very common in childhood and a frequent reason for consultation in pediatric emergency departments. Objectives: to study the management of dental injury in a tertiary hospital. Material and methods: retrospective descriptive study. All patients under 15 years old consulting for dental injury in the Pediatric Emergency Department of Hospital 12 de Octubre between September 2008 and August 2010 were included. During this period of time a specific management protocol of these patients was started. Results: a total of 374 patients were treated, 63% being males, with a median age of 4.45 years. In 84% of cases the etiology was casual, followed by a 3% sports-related accident. Thirty-two percent of the patients were referred from other centers for Maxillofacial Surgery evaluation. In 60% of cases, children were treated exclusively by pediatricians. The most common reasons for maxillofacial surgery evaluation were: suture of gingival laceration (6.4%), dental extraction (3%) and ferulization (1.3%); 83.4% required only medical treatment. Conclusions: dental injury is a common reason for consultation in the pediatric emergency department and referral to other centers. Most patients have mild lesions so they need neither complementary studies nor surgery treatment and should be managed by pediatricians following agreed protocols (AU)

Effect of PDGF-BB, IGF-I Growth Factors and their Combination Carried by Liposomes in Tooth Socket Healing

This work evaluated the bone-forming potential of the platelet-derived growth factor isoform BB (PDGF-BB), insulin-like growth factor I (IGF-I), and mixed PDGF-BB/IGF-I delivered in liposomes compared with phosphate buffered saline (PBS), in the healing process of rat tooth sockets. One hundred and twelve Wistar rats were randomized into 7 groups of 16 animals each and were evaluated at 3, 7, 14 and 21 days after extraction of the maxillary second molars. The left sockets were treated with PBS (P), empty liposome (L), IGF-I in PBS (IP), IGF-I in liposome (IL), PDGF-BB in PBS (PDP), PDGF-BB in liposome (PDL) and both growth factors (GFs) together within liposomes (PDIL). The right sockets were filled with blood clot (BC). Histological and histomorphometric analyses were used to evaluate the formation of new bone and blood vessels. Immunohistochemistry was performed to evaluate the expression of osteocalcin and vascular endothelial growth factor (VEGF) during bone repair. Data were tested statistically using a Tukey's test according to a Dunn's analysis and Mann-Whitney U test followed by Kruskal-Wallis one-way analysis. Results were considered significant when p<0.05. A significantly higher percentage of bone trabeculae and a higher number of blood vessels were observed in the IL, PDL and PDIL groups (p<0.05). However, these GF-liposome groups had statistically similar results. Immunohistochemical assays first detected osteocalcin and VEGF expression at 3 days followed by a peak at 7 days. Lower immunoreactivity levels were observed in the BC, L, P, IP and PDP groups compared with the IL, PDL and PDIL groups (p<0.05). The results suggest that GFs carried by liposomes, either in isolated or mixed forms, enhanced the healing process in rat tooth sockets. The differential expression of the osteogenic markers VEGF and osteocalcin in the early phases of bone healing support these findings.

Este trabalho avaliou o potencial de formação óssea do fator de crescimento derivado de plaquetas na isoforma BB (PDGF-BB), fator de crescimento semelhante à insulina I (IGF-I), e a mistura PDGF-BB/IGF-I administrada em lipossomas comparando com tampão fosfato salino (PBS), no processo de cicatrização de alvéolos dentários de ratos. Cento e doze ratos Wistar foram distribuídos aleatoriamente em 7 grupos de 16 animais cada e foram avaliados aos 3, 7, 14 e 21 dias após a extração dos segundos molares maxilares. Os alvéolos esquerdos foram tratados com PBS (P), lipossomas vazios (L), IGF-I em PBS (IP), IGF-I em lipossomas (IL), PDGF-BB em PBS (PDP), PDGF-BB em lipossomas (PDL) e ambos os fatores de crescimento (GFs) em associação dentro de lipossomas (PDIL). Os alvéolos direitos foram preenchidos com coágulo sanguíneo (BC). As análises histomorfométrica e histológica foram utilizadas para avaliar a formação de novo osso e vasos sanguíneos. Imunohistoquímica foi realizada para avaliar a expressão de osteocalcina e o fator de crescimento endotelial vascular (VEGF) durante o reparo ósseo. Os dados foram testados estatisticamente utilizando o teste de Tukey em acordo com análise de Dunn e o teste Mann-Whitney U seguido pela análise de um passo de Kruskal-Wallis. Os resultados foram considerados significantes quando p<0,05. Uma percentagem altamente significativa de osso trabecular e alto número de vasos sanguíneos foram observados nos grupos IL, PDL e PDIL (p<0,05). Todavia, esses grupos lipossoma-GF tiveram resultados similares estatisticamente. Ensaios de imunohistoquímica inicialmente detectaram a expressão de osteocalcina e VEGF aos 3 dias, seguida por um pico aos 7 dias. Niveis mais baixos de imunorreatividade foram observados em BC, L, P, PI e PDP quando comparados com os grupos IL, PDL e PDIL (p<0,05). Os resultados sugerem que GFs carreados por lipossomas, na forma isolada ou em combinação, aceleram o processo de cicatrização em alvéolos dentários de rato. A expressão diferencial dos marcadores osteogênicos VEGF e osteocalcina, nas fases iniciais de cicatrização óssea, confirma esses achados.

Caracterização morfométrica e molecular do papel de citocinas pró e anti-inflamatórias no processo de reparo ósseo alveolar em condições homeostáticas e infecciosas / Morphometric and molecular characterization of the role of pro- and anti-inflammatory cytokines in alveolar bone repair process under homeostatic and infectious conditions

O metabolismo ósseo é influenciado por fatores endócrinos, genéticos, de crescimento, sistema RANK/RANKL/OPG, além de uma variedade de moléculas regulatórias, como as citocinas. Citocinas têm sido implicadas na patogênese de doenças ósseas, no entanto, ainda pouco se sabe sobre os mecanismos envolvidos na interação entre o sistema ósseo e imunológico no processo de reparo ósseo. O objetivo deste estudo foi caracterizar o papel de TNF-α e IL-10 no reparo ósseo alveolar em condições homeostáticas (controle [C]) e infecciosas (alveolite experimental [A]) pós exodontia em camundongos C57Bl/6 (WT), TNFp55KO e IL-10KO. Após a cirurgia nos grupos infectados foi induzida a alveolite por meio de isquemia do alvéolo e uma suspensão de secreção purulenta. As maxilas foram coletadas em 0h, 7, 14 e 21 dias após a extração do incisivo superior para análises histológica, histomorfométrica e molecular (RealTimePCR). Na análise histomorfométrica foram quantificados os parâmetros coágulo, células inflamatórias, fibras, fibroblastos, vasos sanguíneos, matriz óssea, osteoblastos, osteoclastos, e outros espaço do líquido intersticial e medula óssea. Na análise molecular (RealTimePCR) foram quantificados a expressão de fatores de crescimento, marcadores ósseos e de matriz extracelular, citocinas e quimiocinas envolvidos no processo. Os dados obtidos foram submetidos ao teste OneWay ANOVA seguido do teste de comparação múltipla de Tukey. Os resultados demonstraram que nos camundongos WT-C houve a formação inicial de coágulo (0 hora) com início da expressão de BMP2, BMP4, BMP7, TGFb1 and VEGFa que tiveram aumento gradativo com pico em 7 dias. A expressão de TNF-α e IL10 também tiveram seus picos aos 7 dias em paralelo com contagem de leucócitos, associado com a expressão de CCL2, CCL5 e CXCL1. Nos períodos seguintes houve uma diminuição inflamatória e o aumento de marcadores osteoblásticos/osteogênicos. A indução da alveolite experimental em WT-A resultou no aumento marcante...

Bone metabolism is influenced by endocrine, genetic and growth factors, RANK/RANKL/OPG system, besides a variety of regulatory molecules, such as cytokines. Cytokines have been implicated in pathogenesis of bone diseases, however, little is known about the mechanisms involved in the interaction between skeletal and immune system in the bone repair process. The objective of this study was characterized the role of TNF-α and IL-10 in alveolar bone repair under homeostatic (control [C]) and infectious (experimental alveolitis [A]) conditions in C57Bl/6 (WT), TNFp55KO and IL-10KO mice. After surgery, in infectious groups was induced by ischemia alveolitis the well and a suspension of pus. The maxillas were collected at 0h, 7, 14 and 21 days after extraction of the maxillary incisor for histologic, histomorphometric and molecular (RealTimePCR). In histomorphometric analysis parameters were measured clot, inflammatory cells, fibers, fibroblasts, blood vessels, bone matrix, osteoblast, osteoclast, and other space - the interstitial fluid and bone mar row. Molecular analysis (RealTimePCR) were quantified the expression of growth factors, bone markers and extracellular matrix, cytokines and chemokines involved in the process. The data were submitted to the OneWay ANOVA test followed by Tukey's multiple comparison test. The results showed that in WT-C initial clot formation (0 hours) with early expression of BMP2, BMP4, BMP7, and TGFb1 VEGFa who had gradual increase peaking in 7 days. The expression of TNF-α and IL10 also peaked at 7 days in parallel with leukocyte count, associated with CCL2, CCL5 and CXCL1. In late periods there were decrease of inflammation and markers osteoblastic / osteogenic increased. Induction of experimental alveolitis in WT resulted in a marked increase in expression of TNF-α accompanied by increased expression of CXCL1 and CCL5, increased leukocyte count and decreased of IL10 expression that peaked at 14d, besides prominent...

Caracterização morfométrica e molecar do papel da iNOS no processo de reparo ósseo alveolar em condições homeostáticas e infecciosas / Morphometric and molecular characterization of the role of iNOS in alveolar bone repair process in homeostatic and infectious conditions

A óxido nítrico sintase induzível (iNOS) é uma enzima responsável pela síntese do óxido nítrico, envolvido na regulação de vários processos fisiológicos, com destaque para relevantes efeitos sobre o tecido ósseo. Entretanto, o papel da iNOS no reparo ósseo alveolar permanece pouco conhecido. Assim, o objetivo deste estudo foi caracterizar o papel da iNOS no processo de reparo ósseo alveolar pósexodontia em condições homeostáticas (controle) e infecciosas em camundongos. Para isso, foram utilizados animais das linhagens WT (C57Bl/6) e iNOSKO, divididos em 2 grupos, condição homeostática (exodontia do incisivo superior direito) e alveolite experimental (induzida pela inoculação de uma suspensão de cultura bacteriana), e analisados de acordo com os diferentes períodos experimentais (0, 7, 14 e 21 dias pós-exodontia), através da análise histomorfométrica e molecular. Na análise histomorfométrica, avaliou-se a densidade de volume das estruturas referentes ao coágulo sanguíneo, tecido conjuntivo e tecido ósseo. Na análise molecular, quantificou-se a expressão de mRNA codificando genes de marcadores do metabolismo ósseo; marcadores de osteoclastos; citocinas e quimiocinas, através de reações de RealTimePCR. A expressão de iNOS esteve presente durante todo o processo de reparo ósseo alveolar nos camundongos C57Bl/6, porém de maneira mais expressiva no período de 7 dias pós-exodontia, e se mostrou aumentada pela indução de alveolite. A análise histomorfométrica demonstrou discretas alterações no processo de reparo ósseo alveolar, na ausência de iNOS, tanto em condições homeostáticas quanto infecciosas. Em condições homeostáticas, a ausência de iNOS não impactou de forma significativa o processo de reparo ósseo alveolar pósexodontia, mas se mostrou associada à modulação de vasos sanguíneos. Já em condições infecciosas, a ausência de iNOS se mostrou associada à modulação de células inflamatórias, osteoblastos e osteoclastos. De forma geral, conclui-se que embora...

The inducible nitric oxide synthase (iNOS) is an enzyme responsible for the synthesis of nitric oxide, a reactive molecule involved in the regulation of several physiological processes, highlighting relevant effects on bone tissue. However, the role of iNOS in alveolar bone repair remains unknown. The aim of this study was to characterize the role of iNOS in alveolar bone healing process after dental extraction in homeostatic and infectious conditions in mice. With this aim, WT (C57Bl/6) and iNOSKO mice strains were divided into 2 groups, homeostatic condition (extraction of the upper right incisor) and experimental alveolitis (induced by inoculation of a suspension of bacterial culture), and analyzed according to the different experimental periods (0, 7, 14 and 21 days post-extraction), through molecular and histomorphometric analysis. In histomorphometric analysis, the volume density of structures related to blood clot, tissue and bone were evaluated. The molecular analysis quantified the expression of mRNA encoding genes of defined as bone metabolism markers; osteoclast markers, as well cytokines and chemokines through RealTimePCR reactions. The expression of iNOS was detected during the all process of the alveolar bone repair in C57Bl/6 mice, with an expression peak at 7 days post-extraction time point, and was significantly enhanced by alveolitis induction. Histomorphometric analysis showed small changes in alveolar bone repair process in the absence of iNOS, in both homeostatic as infectious conditions. Under homeostatic conditions, the absence of iNOS did not impact significantly the process of alveolar bone healing after dental extraction, but it was associated with modulation of blood vessels formation. In the infectious conditions scenario, the absence of iNOS was associated with modulation of inflammatory cells, osteoblasts and osteoclasts counts. In general, it is concluded that even the enzyme iNOS module some aspects of alveolar bone...