Minor salivary gland carcinoma: a review of 35 cases.

Minor salivary gland carcinomas represent a heterogeneous group of tumors with broad variation in clinical appearance and histopathology. Clinical data of patients with small salivary gland malignancies were collected from the medical records. Tissue microarray was constructed to determine the expression pattern of 24 proteins in 35 patients with minor salivary gland carcinomas. The choice of markers was based on involvement in neoangiogenesis, cell-to-cell contact, cell-cycle regulation and carcinogenesis. Protein expression data were correlated to patients' clinical data. Overexpression of patched (p = 0.046) and Smo (p = 0.032) was linked to a better overall survival and Glutathione S-transferase π overexpression was linked to prolonged disease-free survival (p = 0.005). Cox-1 (p = 0.035) and VEGFR2 (p = 0.009) were significantly linked to decreased survival for recurrent disease. Bcl-x (84 %), ß-catenin (87 %) and Cox-2 (87 %) were significantly overexpressed in minor salivary gland carcinomas. We have shown that Smo resulted in a better overall survival, whereas Gstπ in improved disease-free survival. VEGFR2 was a prognostic factor for survival after recurrence in patients with minor salivary gland carcinomas. Cyclooxygenase inhibitors and anti-Wnt-1 antibodies might be a potential therapeutic option in an adjuvant setting or for patients with unresectable tumors of the minor salivary glands.

Miniplate osteosynthesis for mandibular angle fractures--A retrospective comparative study of 3 concepts in a temporal cohort.

PURPOSE: Purpose of this retrospective study was to compare fixation of mandibular angle fractures by three different miniplating-concepts (single miniplate, double miniplate, TriLock mandibular angle plate) regarding osteosynthesis failure and hardware removal. METHODS: In this retrospective study a temporal cohort of 184 patients with 194 simple mandibular angle fractures, which had been treated by open reduction and internal fixation via miniplates at the University Clinic of Cranio-, Maxillofacial and Oral Surgery (General Hospital Vienna) in the period of 2005-2011, were included. Patients with pathologic fractures (e.g. tumour or osteonecrosis related) or comminuted fractures were not considered. RESULTS: 9 of 194 (4.6%) fractures showed osteosynthesis failures. The osteosynthesis failure rates were 2.9% in the single miniplate group, 3.4% in the TriLock plate group, and 11.1% in the double miniplate group. In the double miniplate group 33.3% of the patients had undergone hardware removal, 21.4% in the single miniplate group, and 11.4% in the TriLock plate group. CONCLUSION: A single 4-hole locking plate with a thickness of 1.25-1.3 mm guarantees for low osteosynthesis failure rates without postoperative maxillo-mandibular fixation and requires less hardware removal in simple mandibular angle fractures. Two miniplates, longer plates with more holes and thicker plates are prone to hardware removal.

20 years of cleft lip and palate missions.

Volunteer missions for cleft lip and palate (CLP) care in Indonesia (1991-1992), India (1994-2003), Bhutan (2005-2010), and Kenya (2011), took place always at the same Hospital in each country. Altogether over a thousand patients were operated using a conservative protocol: Safety first - no experiments. Five months and 5 kg were the basic rules. For the native doctors, training help for self-help was priority. In the announcements, patients with CLP were primarily addressed. Burns, contractions, tumors, and trauma-cases were the second priority. Fresh trauma was done in night shifts with the local surgeons in order not to interfere. Besides facial esthetics speech was the number one issue, following priorities fell into place. Cultural aspects played a certain role in the different countries and continents.

High neutrophil-to-lymphocyte ratio is an independent marker of poor disease-specific survival in patients with oral cancer.

With growing evidence on the role of inflammation in carcinogenesis, the presence of a systemic inflammatory response has been proposed as having prognostic significance in a wide range of cancers. The aim of the study was to assess the value of pretreatment neutrophil-to-lymphocyte ratio (NLR) in predicting disease-specific survival (DSS) in patients with oral cancer undergoing preoperative chemoradiotherapy. A cohort of 97 patients with locally advanced oral squamous cell carcinoma receiving preoperative chemoradiotherapy was retrospectively examined. The impact of NLR and other potential prognostic factors on DSS was assessed with the Kaplan-Meier method and multivariate Cox regression analysis. Sixty-nine patients had a high pretreatment NLR, with NLR > 1.9 considered as high according to receiver operating characteristic curve analysis. In univariate analysis, high pretreatment NLR (p = 0.018), positive perineural invasion (p < 0.001) and advanced pathologic TNM stage after neoadjuvant therapy (p < 0.001) were predictive of shorter DSS. In multivariate analysis, advanced pathologic TNM stage after neoadjuvant therapy (HR 1.71, 95 % CI 1.17-2.48, p = 0.005), positive perineural invasion (HR 3.67, 95 % CI 1.11-12.13, p = 0.033) and high pretreatment NLR (HR 10.37, 95 % CI 1.28-84.08, p = 0.029) remained independently associated with poor DSS. A high pretreatment NLR is a significant independent predictor of shorter DSS in patients with oral cancer receiving preoperative chemoradiotherapy.

Identifying risk factors for allogenic blood transfusion in oral and oropharyngeal cancer surgery with free flap reconstruction.

PURPOSE: Several observational studies in head and neck cancer have reported that allogenic blood transfusion is associated with increased postoperative complications, increased risk of tumor recurrence, and worse prognosis. The aim of this study was to identify preoperative and intraoperative factors predicting blood transfusion in patients undergoing surgery for oral and oropharyngeal cancer. PATIENTS AND METHODS: We conducted a retrospective cohort study of patients undergoing tumor resection and free flap reconstruction for locally advanced oral and oropharyngeal squamous cell carcinoma between 2000 and 2008. The primary outcome variable was perioperative exposure to allogenic blood transfusion. Univariate and multivariate logistic regression models were used to determine predictors of blood transfusion. RESULTS: A cohort of 142 participants was found eligible. In a multivariate model, Charlson score ≥ 1 (OR, 5.2; 95% CI, 1.4 to 19.3; P = .01), preoperative hemoglobin levels ≤ 12 g/dl (OR, 4.4; 95% CI, 1.2 to 16.2; P = .03), bone resection (OR, 5.1; 95% CI, 1.5 to 17.8; P = .01), and osseous free tissue transfer (OR, 8.8; 95% CI, 1.0 to 74.8; P = .046) were independently associated with an increased risk of blood transfusion. CONCLUSION: Our study identified patient- and surgery-related factors predicting a higher risk of exposure to allogenic blood transfusion. This readily available preoperative information could be used to better stratify patients according to their transfusion risk and may thereby guide blood conservation strategies in high-risk patients.

Survival of patients with pathologic T0N+ oral and oropharyngeal cancer after neoadjuvant therapy and surgery: the minority report.

OBJECTIVES: Treatment outcome of patients with oral and oropharyngeal squamous cell carcinoma (OOSCC) achieving complete pathologic response at the primary site (ypT0) but incomplete response in loco-regional lymph nodes after preoperative chemoradiation (ypN+) is poorly described in the literature. This study's objective was to assess the survival of patients with OOSCC with ypT0N+ disease. STUDY DESIGN: 176 patients with primary locally advanced OOSCC undergoing preoperative chemoradiotherapy were stratified according to the pathologic TNM classification into 6 groups: ypT0N0M0 (46%), ypT0N+M0 (10%), ypTNM I (24%), ypTNM II (4%), ypTNM III (6%), and ypTNM IV (10%). RESULTS: Three-year overall survival (OS) and recurrence-free survival (RFS) rates for the ypT0N+M0 group were both 61.8% and were similar to those of the ypTNM I group (OS 62.4%; RFS rate of 59.2%). CONCLUSIONS: Survival analyses showed that patients with OOSCC with ypT0N+ disease have a similar prognosis to those with pathologic TNM stage I.

Postoperative failure of platelet recovery is an independent risk factor for poor survival in patients with oral and oropharyngeal cancer.

OBJECTIVE: The aim of this study was to evaluate the postoperative platelet count changes in patients with oral and oropharyngeal squamous cell carcinoma undergoing preoperative chemoradiotherapy in order to test the hypothesis that the failure of platelets to recover to normal range within 7 days after surgery represents a significant risk factor for poor survival. MATERIALS AND METHODS: A cohort of 102 patients with primary locally advanced oral and oropharyngeal squamous cell carcinoma undergoing neoadjuvant chemoradiotherapy and surgery was retrospectively analyzed. For each patient, platelet counts were evaluated prior to neoadjuvant treatment, prior to surgery and throughout postoperative days 1 to 7. The Kaplan-Meier method and Cox regression models were used to assess the impact of platelet count changes on survival. RESULTS: Overall survival rate at 5 years was 28% for patients whose platelets did not recover by day 7, with 52% for patients whose platelets remained within a normal level or recovered to this by day 7 (p = 0.005). In multivariate analysis, failure of platelet recovery by day 7 was independently associated with shorter overall survival (p = 0.03). CONCLUSIONS: We demonstrated that the failure of platelets to recover to normal range by the seventh postoperative day is an independent adverse prognostic factor in patients with oral and oropharyngeal cancer undergoing neoadjuvant treatment and surgery. CLINICAL RELEVANCE: Our results indicate that physicians should pay closer attention to monitoring the postoperative platelet count course, as it may predict the clinical outcome of patients with oral and oropharyngeal cancer.

Application of platelet-rich plasma for enhanced bone regeneration in grafted sinus.

PURPOSE: The present study was conducted to evaluate the effect of platelet-rich plasma (PRP) on new bone formation and remodeling after grafting of the maxillary sinus with an algae-derived hydroxyapatite AlgOss/C Graft/Algipore. MATERIALS AND METHODS: Fourteen consecutive patients with severely atrophic maxillae underwent uni- or bilateral grafting of the maxillary sinus with a mixture of collected bone, algae-derived hydroxyapatite AlgOss/C Graft/Algipore (ratio 1:10), and a combined addition of PRP and thrombin (Tissucol Kit; Baxter, Vienna, Austria) to allow for fast clotting. After an average healing period of 7.1 months bone samples were retrieved. Patients from a former consecutive series treated without PRP served as control group. Statistical analysis was done by Welch 2-sample t test and mixed linear model testing. RESULTS: In the coronal specimen portions, mean values for newly formed bone area, biomaterial area and marrow space of 32.2% ± 10.4%, 20.1% ± 13.0%, and 47.7% ± 8.5% were found with PRP, respectively. In the control group the corresponding values were 27.6% ± 13.4%, 20.3% ± 12.9%, and 52.1% ± 9.3%. In the apical specimen portions in the PRP group, the newly formed bone area, biomaterial area, and marrow space was 25.7% ± 15.0%, 23.4% ± 14.9%, and 50.9% ± 12.5%, respectively. The corresponding values in the control group were 17.0% ± 8.6%, 34.5% ± 11.2%, and 48.5% ± 8.5%. CONCLUSIONS: Statistical evaluation of the samples proved significantly better overall resorption of algae-derived hydroxyapatite AlgOss/C Graft/Algipore and increased new bone formation when PRP was used, especially in the apical region.

Survival of patients with HPV-positive oropharyngeal cancer after radiochemotherapy is significantly enhanced.

BACKGROUND: The purpose of this study was to evaluate the incidence and clinical significance of HPV (Human papilloma virus) infection in patients with head and neck cancer who had received radiotherapy in Eastern Austria. PATIENTS AND METHODS: 88 patients with head and neck cancer including 26 patients with oral cavity cancer, 45 patients with oropharyngeal cancer, seven patients with laryngeal carcinoma and ten patients with carcinoma of the hypopharynx were screened for high risk HPV by immunohistochemistry, PCR (Polymerase Chain Reaction) and in-situ hybridization. 29 out of 45 patients with a squamous cell carcinoma of the oropharynx received radiotherapy alone, radiotherapy in combination with cisplatin or cetuximab. RESULTS: Of the investigated 29 patients with oropharyngeal cancer receiving conservative treatment, 11 had a HPV-positive and 18 a HPV-negative tumor. Patients received radiation ± cisplatin or cetuximab, where the HPV-positive patients had a significant better response to treatment and overall survival (p = 0.015) as well as disease-free survival (p = 0.001) after therapy. CONCLUSION: Patients with oropharyngeal carcinoma and a positive HPV status respond considerably better to radiochemotherapy than patients with HPV-negative tumors. HPV screening is a simple procedure and can easily be implemented in routine pathology investigations and should be included in standard operational procedures for the diagnosis and therapy of head and neck cancer patients.

Multimodal treatment of patients with minor salivary gland cancer in the case of recurrent disease.

BACKGROUND: Our aim in this study was to identify prognostic factors and the optimal therapeutic management in patients with minor salivary gland carcinomas. METHODS: Overall and disease-free survival and overall survival after recurrence in patients with adenoidcystic carcinoma (n = 25), mucoepidermoid carcinoma (n = 8), adenocarcinoma (n = 5), carcinoma ex pleomorphic adenoma (n = 4), and others (n = 5) were correlated to clinical data. RESULTS: Overall survival correlated to treatment modality (p = .039) and T classification (p = .003), whereas prolonged disease-free interval correlated to treatment (p < .001) and T classification (p = .009). Overall survival after recurrence correlated to treatment of recurrence (p = .006) and initial T classification (p = .02). Multivariate analysis showed that overall survival after recurrence correlated to treatment of recurrence (p = .019) and initial T classification (p = 0.019). T classification was a prognostic factor for overall survival (p = .002) and disease-free interval (p = .002). CONCLUSIONS: The initial tumor classification is a clinical predictor for patients' overall and disease-free survival and overall survival after recurrence. Multimodal treatment significantly improves patients' overall survival.

P50 suppression, prepulse inhibition, and startle reactivity in the same patient cohort suffering from posttraumatic stress disorder.

BACKGROUND: Psychophysiological alterations like impaired gating and increased startle have been reported in patients with posttraumatic stress disorder (PTSD). However, findings are inconsistent, and potential relationships to symptomatology remain unclear. AIMS: The present study investigates two distinct operational measures of gating and startle reactivity within the same patients suffering from PTSD and their relationship to PTSD symptomatology. METHODS: Prepulse inhibition of the acoustic evoked startle reflex, P50 suppression of auditory event related potentials, and startle reactivity were assessed in three distinct experiments in 27 PTSD patients and compared to 25 healthy control subjects. RESULTS: PTSD patients exhibited impaired P50 suppression and exaggerated startle. Lower P50 suppression was associated with higher levels of general psychopathology. Patients and control subjects did not differ in PPI. LIMITATIONS: Some of the limitations include, that the control group compromised of non-trauma exposure subjects and menstrual cycle in female participants potentially affecting PPI was not controlled. CONCLUSIONS: Deficient P50 gating, not related to specific trauma or distinct symptom clusters reflects a robust finding in PTSD patients. In contrast, further research is needed to clarify whether PPI is affected in PTSD.

Mineral apposition rates provide significant information on long-term effects in BMP-induced bone regeneration.

In this study, a CaP biomaterial was used as a carrier for rhBMP-2. Biomaterials were investigated in calvarial and femoral defects using a rabbit animal model, with unloaded biomaterials serving as control. Fluorochrome labels were administered at days 14 and 70. Specimens were retrieved after 12 weeks for histological analysis. When area fractions were assessed by conventional histomorphometry, no significant effect of rhBMP-2 on the amounts of regenerated bone and residual biomaterial were seen by 12 weeks. After mineral appositional rate (MAR) measurement using double labels, calculation yielded significantly higher MARs for defects at both implantation sites, when compared with surrounding bone, whether or not biomaterials were loaded with rhBMP-2. Analyzing the effect of rhBMP-2, both defect sites showed significantly higher MARs in the rhBMP-2 group. MARs of bone surrounding the defects had also been elevated significantly by rhBMP-2 at calvarial and femoral implantation sites. It is concluded that MAR measurement is suitable to identify long-term effects of rhBMP-2 on bone formation at a time when conventional histomorphometry using fractional area determination is inadequate. Also, by MAR assessment, effects of rhBMP-2 on surrounding bone can be documented.

Surgical treatment of squamous cell carcinoma of the maxilla and nasal sinuses.

PURPOSE: In the treatment of oral squamous cell carcinoma of the maxilla and paranasal sinuses, radical surgery and reconstruction with free flaps is accepted among many clinics. Nevertheless, the treatment protocols vary considerably. This study was performed to present our experience in the treatment of maxillary squamous cell carcinoma with surgical means alone, and to try to identify crucial prognostic factors for the patients' survival. PATIENTS AND METHODS: Thirty-six patients with primary resectable squamous cell carcinoma were included in the study. The mean age was 63 years (43-87 years) and 50% presented in advanced tumor stage (T4). Five patients (14%) already had cervical metastases. All patients were treated by radical surgery alone, and the resulting defects were closed by means of local or free flaps or the use of an obturator, respectively. RESULTS: The overall 5-year survival rate was 64%; the recurrence rate was 33%. Only patients who presented in T3 or T4 stages or had no free resection margins died during the follow-up period. Sixty-nine percent of the patients who died passed away within the first 12 months of follow-up. The 5 patients with cervical metastases received therapeutic neck dissection and showed no regional recurrence. In cases of R1 resection, adjuvant radiotherapy was applied. CONCLUSIONS: The sole surgical treatment of squamous cell carcinomas of the maxillary region led to good results, and can therefore be seen as a valuable strategy. Free resection margins and early detection of the tumor are the most important factors for success.

Deliberate self-harm in female patients with affective disorders: investigation of personality structure and affect regulation by means of operationalized psychodynamic diagnostics.

This study investigated psychodynamically relevant dimensions in female depressive patients with and without deliberate self-harm (DSH). DSH is often observed in depressive patients and frequently shows a correlation with personality disorders. Forty female depressive patients with and without DSH were investigated after recovery from acute depressive pathology by means of "operationalized psychodynamic diagnostics" (OPD). Patients with DSH had a significantly lower level of integration in the OPD dimension "structure," and their "interpersonal relationships" showed dysfunctional interaction patterns. They also had a significantly higher rate of personality disorders. These results underline the significance of aspects of personality structure in female depressive patients with DSH, and enable a deeper understanding of their dysfunctional defense strategies, the connections with underlying disturbed affect regulation, and vicious circles in the therapeutic transference-countertransference relationship. OPD has been shown to be a useful tool for empirical research into therapeutically relevant dimensions of personality.

Unilateral face swelling as first manifestation of metastatic pancreatic cancer: case report and review of the literature.

OBJECTIVE: Metastasis to the jaw is a rare finding in pancreatic cancer; only five cases of tumor spread to the oral region have been described. CASE REPORT: We report on a previously healthy 54-year-old man who attended the hospital in 2006 because of a mandibular mass. Histology was positive for adenocarcinoma and computed tomography led to the diagnosis of pancreatic cancer. Chemoradiotherapy was started but had to be stopped early because of intraoral bleeding from the metastasis. The patient subsequently received palliative chemotherapy. The primary cancer was stabilized but the mandibular mass progressed despite cytostatic therapy. Despite best supportive measures the patient died nine months after presentation. CONCLUSION: In making the decision on whether metastasectomy should be performed in an uncommon site of metastatic spread such as the mandibula, both the possibility of cure and also the potentially decreased response to conservative therapy and the patient's decreased quality of life have to be considered.

[Automutilistic behaviour in female patients with affective disorders: investigation of personality structure and affect regulation by means of Operationalized Psychodynamic Diagnostics (OPD)]. / Automutilistisches Verhalten bei Patientinnen mit affektiven Störungen: Untersuchung der Persönlichkeitsstruktur und Affektregulation mittels Operationalisierter Psychodynamischer Diagnostik (OPD).

UNLABELLED: Automutilistic behaviour is frequently correlated with personality disorders and should be differentiated from suicidal behaviour during acute episodes of affective disorders. The aim of the study was to investigate psychotherapeutically and psychodynamically significant personality traits and affect regulation. The dimensions "relationship", "conflict" and "structure" were examined by means of Operationalized Psychodynamic Diagnostics. SAMPLE: 20 female patients with depression and automutilistic behaviour and 20 age-matched female subjects with a similar educational background, suffering from depression without automutilistic behaviour. RESULTS The female patients with depression and automutilistic behaviour could be differentiated from the control group in all categories in the OPD dimension "structure". They showed an "isolated" and "disclosed" self-image. This negative self-perception corresponded with a negative countertransference. There were no differences between the patients with automutilistic behaviour and the control group regarding the OPD dimension "conflict". Low and moderate levels of integration were prominently correlated with the autonomy-dependence conflict. CONCLUSION The results underline the significance of aspects of personality structure in automutilistic behaviour seen in female patients with depression. Operationalized Psychodynamic Diagnostics can reveal therapeutically relevant personality dimensions for empirical research.

[Neurotoxicity related to lithium-risperidon combination treatment in a patient with schizoaffective disorder]. / Neurotoxische Enzephalopathie unter Kombinationsbehandlung mit Lithium und Risperidon bei einer Patientin mit schizoaffektiver Störung.

OBJECTIVE: The case of a schizoaffective patient with a neurotoxic encephalopathy related to lithium-risperidon combination treatment is explored. METHOD: A case report and the relevant theoretical and clinical deliberations are described. CONCLUSIONS: Neurotoxicity related to lithium-risperidon combination treatment is the result of an interaction of different ethiopathogenetic mechanisms. The EEG is the most important diagnostic parameter.

Bone morphogenetic proteins 5 and 6 stimulate osteoclast generation.

Bone regeneration is required for fracture-healing, and different procedures have been used to promote osteogenesis. Recently, BMP-2 has been shown to induce bone formation in vivo and has been tested in clinical trials. A recent in vitro study evaluated the osteogenic activity of 14 BMPs on osteoblastic progenitor cells with an osteogenic hierarchical model in which BMP-2 and BMP-6 may play an important role in inducing osteoblast differentiation. Although the relative osteoinductive activity of each BMP is important, bone regeneration is a process consisting of bone formation and bone resorption. Therefore, it remains unclear which effects BMP-5 and -6 have on the generation of osteoclasts and by which mechanism osteoclastogenesis is stimulated. To compare osteoclastic potency of each BMP, primary murine bone marrow cells were treated with human recombinant BMP-2, BMP-5, or BMP-6 and 1,25-(OH)2 vitamin D3 and stained for the TRAP enzyme. Osteogenic activity of BMP-5 was determined by measuring induction of ALP-activity and proliferation after incubation with primary murine osteoblasts. For elucidating the molecular mechanism, primary bone marrow cells with various concentrations of OPG were added to the TRAP assay and mRNA levels of RANKL and OPG were measured after stimulation with BMP-5. The presented data show that BMP-5 and BMP-6, unlike BMP-2, enhanced the formation of murine TRAP+/MNCs in a biphasic curve. BMP-5 and -6 were less potent in stimulating osteoclastogenesis compared to BMP-2. Concerning the effects of BMP-5 on osteoblasts, there was a dose-dependent increase of ALP activity and proliferation up to a maximum dose of 300 ng/mL. At the mRNA level, BMP-5 increased the RANKL/OPG ratio. In conclusion, this study demonstrates that in contrast to BMP-2, BMP-5 and -6 influences the generation of osteoclasts in a biphasic mode. Both proteins might be very important regulators of bone homeostasis, and therefore, potent candidates for future treatment strategies of bone regeneration.

The effect of three different calcium phosphate implant coatings on bone deposition and coating resorption: a long-term histological study in sheep.

The present study investigated the hypothesis that hydroxyapatite (HA), tricalcium phosphate (TCP), and a HA-gel coated on endosseous titanium (Ti) implants by spark discharging (SD) and dip coating would achieve predictable osseointegration without evident bioresorption of the coatings on the long term. A costal sheep model was used for the implantation of the HA/SD, HA/TCP/SD, and HA-gel/SD specimens, which were retrieved 6 and 12 months following implantation. HA and Ti coatings on implants obtained by conventional plasma spraying (HA/PS, Ti/PS) were used as controls. Microscopy showed that osseointegration was achieved from all types of implants. No evidence for bioresorption of the HA/SD, HA/TCP/SD, and HA-gel/SD coatings was present but cohesive failure with disruption of the coating/implant interface was seen. A statistical analysis of the histomorphometrical data showed no time-dependent effect, however. HA/PS coatings achieved significantly higher bone-implant contact (BIC) percentages of the total implant surface (toBIC) than the other types of coatings (P=0.01). If the BIC percentages were traced separately for implant portions placed into cortical and cancellous bone (coBIC and caBIC, respectively), detailed analysis showed that the caBIC values of HA-gel/SD and HA/PS coatings were significantly higher than that of the other types of coatings (P=0.01). CaBIC values were highly correlated with toBIC values (P<0.001). The present study showed that the preparation techniques used produced thin, dense, and unresorbable coatings that achieved osseointegration. Compared with the control coatings, however, only HA-gel/SD coating can be recommended from the investigated preparation techniques for a future clinical use if a better coating cohesion is achieved.

HA/TCP compounding of a porous CaP biomaterial improves bone formation and scaffold degradation--a long-term histological study.

In the present study, two biphasic calcium phosphate biomaterials (BCP) with HA/TCP ratios of 50/50 and 30/70 were obtained from a pure HA biomaterial. The biomaterials which showed the same three-dimensional geometry were implanted into corticocancellous costal defects of sheep. In the specimens of all three biomaterials, abundant bone formation, mineral dissolution from the biomaterial scaffolds, and active cellular resorption of the scaffolds was present after 6 and 12 months. Backscattered electron microscopy showed bone invasion into the pores of the scaffolds and micromechanical interlocking at the bone/biomaterial interface without intervening soft tissue. The pattern of bone formation and scaffold resorption was different for cortical and cancellous bone. No time-based effect, however, was observed. Overall, the BCP biomaterials had formed significantly more bone than the HA biomaterial. Also, scaffold resorption, which was followed by a replacement with newly formed bone, was significantly higher in the BCP biomaterials. Although no significant differences were observed between both BCP biomaterials, the present study had confirmed the assumption that HA/TCP compounding was suitable to improve bone formation and scaffold resorption in the investigated biomaterials and at the same time maintain the osteoconductive properties of the scaffolds.