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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Orbit rehabilitation with extraoral implants: impact of radiotherapy.

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

Evaluation of a ß-calcium metaphosphate bone Graft containing bone morphogenetic protein-7 in rabbit maxillary defects.

BACKGROUND: Calcium phosphate-based materials have been widely used as bone substitutes and more recently are being exploited together with growth factors as bone tissue engineering scaffolds regulating cell behavior. The aim of this study is to evaluate the in vitro and in vivo response to a newly developed calcium metaphosphate (CMP) bone graft, with and without bone-stimulating growth factor. METHODS: Porous scaffolds of CMP were developed and extensively tested in vitro. Subsequently, CMP grafts with osteogenic protein-1 (OP-1) (test) and without OP-1 (control) were implanted into experimental rabbit maxillary bone defects. Animals were sacrificed at 2, 4, and 8 weeks, and samples were examined with microcomputed tomography (micro-CT) and processed for histomorphometric analysis. RESULTS: At 8 weeks, the scaffolds containing OP-1 induced greater bone formation (P = 0.018) than CMP alone, based on histomorphometric evaluation (percentage bone area: test: 57.1 ± 5.6; control: 49.4 ± 7.7) and micro-CT analysis (percentage bone volume density: test: 63.46 ± 5.61; control: 51.20 ± 6.71). Thus, these data indicated that both test and control CMP grafts showed a good degree of bone formation. Furthermore, the CMP materials showed signs of resorption from 4 weeks, and no graft materials were observed at 8 weeks. CONCLUSIONS: In vitro, the OP-1 loaded graft demonstrated a release profile and bioactivity over a 28-day period. In vivo testing confirmed enhanced bone formation of the OP-1 loaded graft after 8 weeks of healing.

Formação óssea e contato osso-implante após irradiação e colocação do implante dentário: estudo experimental no modelo de tíbia em ratos / Bone formation and bone-implant contact after irradiation and dental implant placement: an experimental study in the rat tibiae model

Objetivo: comparar a formação óssea e o contato entre osso e implante (BIC) em osso irradiado usando um modelo de tíbia em ratos. Material e métodos: seis animais Rattus norvegicus (Wistar, 90 a 120 dias, peso entre 350 a 400 g) receberam 30 Gy de radiação ionizante (distância pele-fonte: 80 cm) na tíbia direita (grupo-experimental). A tíbia esquerda serviu como grupo-controle. Após 30 dias, implantes de titânio (2,5 mm diâmetro, 3 mm-comprimento, superfície tratada) foram colocados em ambos os grupos. Todos os animais foram sacrificados após 56 dias, e as amostras foram analisadas histomorfometricamente para área de formação óssea no espaço entre as roscas e o BIC. Resultados: para a formação óssea, as médias foram 44,91 ± 13,31% (grupo-controle), contra 43,16 ± 28,73% (grupo-experimental) (teste t; p=0,44). Para o contato entre osso e implante, o percentual foi de 39,51 ± 17,22% contra 33,36 ± 26,15%, respectivamente (teste t, p=0,31). Conclusão: dentro dos limites deste estudo, não houve diferença na formação óssea e no contato entre osso e implantes na avaliação histomorfométrica de implantes instalados em tíbias de ratos, submetidas previamente a 30 Gy de radiação ionizante.

Vertical ridge augmentation of an atrophic posterior mandible with an inlay technique and cancellous equine bone block: a case report.

This report describes a successful implant prosthetic rehabilitation in an atrophic left posterior mandible in a 62-year-old man using a cancellous equine bone block as grafting material. Four months later, two bone specimens were retrieved for histologic evaluation and two dental implants were placed. Computed tomography and conventional radiography showed a 5-mm mean vertical bone gain. The biopsies showed new bone formation within the cancellous portion of the blocks and no foreign body reaction. Cancellous equine bone grafts may be an effective alternative to autogenous bone and inorganic bovine bone grafting for reconstruction of the posterior mandible using the inlay technique.

Surgical reconstruction of peri-implant bone defects with prehydrated and collagenated porcine bone and collagen barriers: case presentations.

BACKGROUND: Surgical reconstruction of peri-implant defects is challenging and unpredictable due to, for example, the extent of the bone defect or the osteogenic potential of adjunctive materials used. PURPOSE: To study the healing capacity of a new bone xenograft material in the treatment of peri-implant defects. MATERIAL AND METHODS: In three cases with advanced peri-implant defects, flap surgery was performed. After thorough debridement including cleaning of the exposed implant surface, prehydrated and collagenated porcine bone (PCPB) particles were placed into the defect. A bioresorbable collagen barrier was adapted and placed over the defect and the flaps were relocated. After 6 and 12 months of healing, clinical and radiographic examinations were done. In one case, the surgical procedure was repeated 6 months postoperatively. One year after the second surgery, a bone biopsy was harvested and analyzed with histology. RESULTS: All defects healed uneventfully. At 6 months, probing depths were reduced by 3-4 mm with no bleeding on probing or pus formation. At 12 months, healthy peri-implant conditions were found. Intra-oral radiographs showed gain of the marginal bone level by 2-4 mm. In the case where reconstructive surgery was repeated, histology showed osteoconductive properties as bone formation with typical osteoblastic seams was observed directly on the surface of the grafted particles. CONCLUSION: The presented cases show that PCPB have favorable properties enhancing bone regeneration in peri-implant bone defects.

Osseointegrated implants associated with PRP in the rehabilitation of irradiated patient with SCC of the tongue. Case report

Background: Young patients with squamous cell carcinoma (SCC) of the oral cavity are an unusual occurrence. Also, malignant tumour treatment can result in severe mutilation with unfavourable impact on cosmetic and function. Case report: This is a case of a 23-year-old man who presented a SCC of the tongue. After oncological treatment with resection and irradiation, he was rehabilitated using osseointegrated implants associated with platelet rich plasma in order to improve patient rehabilitation. Discussion: After a six-month healing period all implants were stable and clinically osseointegrated and masticatory, phonetic and aesthetic functions were restored. Results show that under controlled procedures, osseointegration is achievable even in low bone quality in irradiated sites, improving the patient’s quality of life.

Histologic evaluation of soft tissue integration of experimental abutments for bone anchored hearing implants using surgery without soft tissue reduction.

OBJECTIVE: The protocol for bone-anchored hearing implants (e.g., Baha) surgery involves reduction of soft tissues around the abutment to minimize the risk of skin-related complications. It is hypothesized that good soft tissue outcomes may be achieved without performing skin reduction if improved abutment designs and/or materials are used that provide enhanced integration with surrounding soft tissues. The aim of the study was to investigate soft tissue response to different abutment designs/materials. METHODS: Thirty-six Baha implants and abutments were inserted in the skull of six sheep without performing soft tissue reduction. Four different abutments were used: 1) standard Baha abutments, 2) hydroxyapatite-coated standard Baha abutments, 3) concave titanium abutments, and 4) hydroxyapatite-coated concave abutments. Healing times of 1, 2, and 4 weeks were used (2 animals per time point). Samples were analyzed using descriptive histology and morphometric measurements, and results were compared using Wilcoxon's signed-ranked test. RESULTS: Histologic assessment showed healthy soft tissues around the abutments with limited or no signs of inflammation. Hydroxyapatite-coated abutments showed tight adherence with dermis and limited epidermal downgrowth and pocket formation. Weaker adherence, often associated with significant epidermal downgrowth and pocket formation, was noted for noncoated titanium abutments. The mean pocket depth for abutment types A, B, C, and D was 1.38, 0.42, 1.51, and 0.24 mm, respectively. The difference between C and D was statistically significant (p = 0.031). CONCLUSION: The results showed enhanced dermal adherence and reduced epidermal downgrowth and pocket formation for hydroxyapatite-coated abutments, with the most significant effect recorded for the hydroxyapatite-coated abutments with a concave shape.

Maxillary sinus augmentation using prehydrated corticocancellous porcine bone: hystomorphometric evaluation after 6 months.

BACKGROUND: Insufficient alveolar bone height often prevents the placement of standard dental implants in the posterior part of edentulous maxilla. In order to increase adequately the vertical dimension of the reabsorbed alveolar process, a sinus lift procedure is often necessary. The aim of this study was to evaluate histologic results of a prehydrated corticocancellous porcine bone used in maxillary sinus augmentation. METHODS: Patients (age 18-70 years) with a residual bone height requiring a maxillary sinus augmentation procedure to place dental implants were eligible for this study. All patients were treated with the same surgical technique consisting of sinus floor augmentation via a lateral approach. The space obtained by elevation of the mucosa wall was grafted with prehydrated and collagenated corticocancellous porcine bone. Biopsies were harvested 6 months after the augmentation procedures. RESULTS: Twenty-four patients were enrolled. The mean percentage of new formed bone was 43.9 ± 18.6% (range 7.5-100%), whereas the mean percentage of residual graft material was 14.2 ± 13.6% (range 0-41.9%). The new bone/residual graft material ratio in the maxillary sinuses was 3.1. The mean soft tissues percentage was 41.8 ± 22.7% (range 0-92.5%). CONCLUSION: The present study suggested that porcine bone showed excellent osteoconductive properties and could be used successfully for sinus augmentation. Moreover, the porcine bone showed a high percentage of reabsorption after 6 months; this might be because of the presence of collagen and the porosity of the graft material.

Gene expression of inflammation and bone healing in peri-implant crevicular fluid after placement and loading of dental implants. A kinetic clinical pilot study using quantitative real-time PCR.

PURPOSE: Early detection of healing complications after placement of dental implants is a pressing but elusive goal. This paper proposes a non-invasive diagnostic tool for monitoring healing- and peri-implant disease specific genes, complementary to clinical evaluations. MATERIAL AND METHODS: Eighteen partially edentulous patients were recruited to this pilot study. Three Brånemark TiUnite® implants/patient (Nobel Biocare) were placed in a one-stage procedure. Abutments with smooth or rough (TiUnite®) surface were placed. The test group (n = 9) received fixed bridges (immediate loading), whereas the control group (n = 9) implants were loaded 3 months after surgery. In addition to clinical measurements, crevicular fluid was collected using paper strips at the implant abutments 2, 14, 28, and 90 days postoperative. mRNA was extracted, purified, and converted to cDNA. Quantitative PCR assays for IL-1ß, TNF-α, Osteocalcin (OC), Alkaline Phosphatase (ALP), Cathepsin K, Tartrate Resistant Acid Phosphatase, and 18S ribosomal RNA were designed and validated. Relative gene expression levels were calculated. RESULTS: One implant was lost in the control group and three in the test group. In one test patient, one implant showed lowered stability after 2 to 4 weeks and was unloaded. Later implant stability improved which allowed for loading after 3 to 4 months. TNF-α and ALP most commonly showed correlation with clinical parameters followed by IL-1ß and OC. The strongest correlation was found for TNF-α with clinical complications at 2 and 14 days (p = .01/r = -048, and p = .0004/r = -0.56, respectively; test and control groups together). In some cases, gene expression predicted clinical complications (TNF-α, ALP, CK). CONCLUSION: This study is based on samples from few individuals; still, some genes showed correlation with clinical findings. Further studies are needed to refine and optimize the sampling process, to find the appropriate panel, and to validate gene expression for monitoring implant healing.

Characterization of epidermal growth factor-induced dysplasia in the adult rat subventricular zone.

Epidermal growth factor (EGF) is a mitogen widely used when culturing adult neural stem cells in vitro. Although proliferative effects can also be observed in vivo, intracerebroventricular infusion of EGF has been found to counteract neuronal determination and promote glial differentiation instead. However, EGF receptor activation has different effects on the subventricular zone (SVZ) in mice and rats, possibly because of species differences in SVZ cell composition. Specifically in the rat, EGF stimulation of the SVZ induces the formation of hyperplastic polyps. The present study aims at molecular and morphological characterization of these subventricular polyps. Using immunohistochemistry, electron microscopy, and gene expression analysis, we demonstrate in hyperplastic EGF-induced polyps an upregulation in protein expression of Sox2, Olig2, GFAP, nestin, and vimentin. We found polyp-specific dysplastic changes in the form of coexpression of Sox2 and Olig2. This highly proliferative, Sox2/Olig2 coexpressing dysplastic cell type is >10-fold enriched in the hyperplastic polyps compared with control SVZ and most likely causes the polyp formation. Unique ultrastructural features of the polyps include a lack of ependymal cell lining as well as a large number of cells with large, light, ovoid nuclei and a cytoplasm with abundant ribosomes, whereas other polyp cells contain invaginated nuclei but fewer ribosomes. EGF also induced changes in the expression of Id genes Id1, Id2, and Id4 in the SVZ. Taken together, we here demonstrate dysplastic, structural, and phenotypical changes in the rat SVZ following EGF stimulation, which are specific to hyperplastic polyps.

The influence of bone type on the gene expression in normal bone and at the bone-implant interface: experiments in animal model.

BACKGROUND: Studies on the biological processes in different bone types and the reaction of different bone types to biomaterials are often hindered because of the difficulties in sampling procedures and lack of sensitive techniques. PURPOSE: The purpose was to assess the suitability of quantitative polymerase chain reaction (qPCR) for investigation of the biological differences between cortical and trabecular bone types and their responses to biomaterials. MATERIALS AND METHODS: Gene expression of selected markers in rat bone samples from different locations was evaluated. Samples were harvested by trephines from the trabecular femoral epiphysis, cortico-trabecular proximal tibial metaphysic, and the cortical distal tibial metaphysis. Gene expression was also evaluated at the surfaces of anodically oxidized implants retrieved from cortical and trabecular sites after 3 days of implantation. mRNA in the bone samples and in the tissue associated with the implant surfaces was extracted and quantified using qPCR. Tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), alkaline phosphatase (ALP), osteocalcin (OC), tartrate-resistant acid phosphatase (TRAP), cathepsin K (CATK), and 18S ribosomal subunits (18S) were analyzed. RESULTS: In the bone samples, higher expression of ALP, OC, TRAP, and CATK was found in femoral epiphysis compared to proximal or distal tibial metaphysis, indicating a higher turnover in the trabecular bone. On the other hand, TNF-α and IL-1ß showed higher expression in both tibia sites compared with the femur site, which suggests higher inflammatory potential in the cortical bone. In response to the oxidized implants trabecular bone expressed a higher level of IL-1ß, whereas the implants in cortical bone were associated with higher expression of ALP and OC. CONCLUSION: There are biological differences between cortical and trabecular bone types, both in the normal steady-state condition and in response to biomaterials. Such differences can be characterized and discriminated quantitatively using a sensitive technique such as qPCR.