A comparative study of cyanoacrylate-based tissue adhesive and surgical sutures on marginal flap stability following coronally advanced flap.

INTRODUCTION: The present study evaluated the biomechanical characteristics of cyanoacrylate-based tissue adhesive (TA) compared to surgical sutures in coronally advanced flap (CAF) procedures using an ex-vivo model. MATERIAL AND METHODS: Thirty-six half-pig mandibles were divided into three groups, n=12 each: (I) CAF fixed with sutures (sling and tag suture technique), (II) CAF fixed with TA, and (III) CAF fixed with sutures and TA. At mandibular premolars, gingival recession defects extending 3 mm apical to the cemento-enamel junction (CEJ) were created. CAF procedures were performed using a split-full-split approach, with coronal advancement of the flap to 1 mm above the marked CEJ and stabilization according to the respective groups I-III. Marginal flap stability against pull-of forces (maximum tensile force) was measured with a universal material testing machine until the CEJ became visible. RESULTS: The comparison between groups I-III demonstrated a significantly increased maximum tensile force for the TA (II) compared to the suture group (I) (p<0.001). A significantly increased maximum tensile force was found for the suture and TA (III) compared to the suture group (I) (p<0.001). There was also a significantly increased maximum tensile force in the suture and TA (III) compared to the TA group (II) (p<0.001). CONCLUSION: The results suggest that cyanoacrylate-based TA can increase marginal flap stability compared to sutures in CAF procedures. CLINICAL RELEVANCE: Cyanoacrylate-based TA can be considered a useful and valuable adjunct to conventional suturing techniques in periodontal plastic surgery, especially in cases where high flap stability is required. The results of this ex-vivo study can only be transferred to the clinical situation with limitations. Clinical long-term follow-up data must be generated.

#OMFSurgery: analyzing the use of social media applications in oral and maxillofacial surgery resident training.

BACKGROUND: Despite its increasing popularity, to our knowledge the use of social media applications (SM) for residents' training in Oral and Maxillofacial Surgery (OMFS) has not been investigated yet. The aim of this study was to evaluate the use of SM applications by OMFS residents for post-graduate training in Germany. METHODS: For explorative assessment, an online questionnaire containing 27 questions about the current use of SM for resident training was sent to OMFS residents in Germany. RESULTS: Sixty-four colleagues participated to the study. Thirty-four participants (54%) responded to regularly use those platforms mainly for OMFS-related content. YouTube (65%, n = 37), Instagram (48%, n = 27), ResearchGate (25%, n = 14) and WhatsApp (16%, n = 9) were the most popular platforms. (Surgical) videos (97%, n = 59), pictures and graphics (82%, n = 50) were the mainly accessed contents. Forty-four participants (69%) stated that SM substantially contributed to their OMFS training. Dentoalveolar surgery and implantology (66%, n = 35) and aesthetic facial surgery (55%, n = 29) content contributed most to OMFS resident training. Fifty-one participants (80%) recommended an official SM account of the DGMKG. CONCLUSIONS: SM is frequently used by OMFS residents for the consumption of training-related content. There is an imbalance toward dentoalveolar and facial aesthetic surgery regarding the presented content. Academic institutions and societies should complement their educational activities to not miss this emerging educational innovation. Official SM content by academic institutions and societies could contribute to the existing educational activities.

Evaluation of Medication-Related Osteonecrosis of the Jaw (MRONJ) in Terms of Staging and Treatment Strategies by Dental Students at Different Educational Levels.

Background: The role of medication-related osteonecrosis of the jaw (MRONJ) as a dento-maxillo-facial pathology is becoming increasingly important due to its growing prevalence. The success of preventive and therapeutic measures relies mainly on the dentist's ability to correctly diagnose the disease. Methods: The aim of this study was to evaluate the skills of dental students of different educational levels in choosing the correct stage, diagnostics, and treatment option for MRONJ based on clinical and radiographic imaging (panoramic radiograph, CBCT). The study was designed as a cross-sectional cohort study. Twenty dental students were asked to complete a questionnaire in their third and fifth year of studies in which they had to correctly stage the disease, choose the radiological diagnostics and recommend the treatment. The control group contained experienced oral and maxillofacial surgeons. Results: With an overall performance of 59% (third year: 145.2/248 points; fifth year: 145.3/248 points), no statistically significant difference between the educational levels could be observed. The classification based on CBCT imaging was significantly more often correct compared to panoramic radiographs (p < 0.001). Conclusions: This study highlights students' lack of knowledge in staging, diagnostics, and treatment of MRONJ, even though the CBCT positively affected decision-making. No significant increase in knowledge could be confirmed through clinical education. This study highlights the need for students to catch up on MRONJ diagnostics and treatment planning. Further expansion of teaching in this disease's context and X-ray diagnostics is needed.

Biomechanical evaluation of cyanoacrylate-based tissue adhesive for intraoral wound closure.

OBJECTIVES: The aim of this study was to analyze the biomechanical characteristics of a novel cyanoacrylate-based tissue adhesive (CTA) for soft-tissue closure of the (non-) tooth-bearing alveolar process and around dental implants. MATERIALS AND METHODS: Halves of porcine mandibles (n = 21) were randomly divided into three experimental intraoral wound closure groups (A-C) with three different mucoperiosteal flap types (F1-3, n = 7 each): F1, crestal incision between the last incisor and the canine with a mesial and distal vestibular relief; F2, crestal double-T-shaped incision and dental implant placement between the canine and the first premolar; and F3, trapezoidal incision on the second premolar. F1-3 were respectively closed using (A) monofil non-resorbable sutures, (B) CTA, and (C) a combination of both. Tensile strength (TS) and elasticity (E) measurements were performed for biomechanical analysis. RESULTS: In F1, CTA showed a significantly reduced TS compared to A (p < 0.001) and C (p < 0.01). In F2, an increased TS of C compared to A (p < 0.01) and B (p < 0.001) was found. Here, E was significantly increased in C compared to B (p < 0.02). In F3, TS was significantly decreased in B compared to A (p < 0.01) and C (p < 0.001). The E in group C was significantly increased compared to B (p < 0.01). CONCLUSIONS: Different biomechanical characteristics between CTA and sutures were found. CTA could be a possible alternative to sutures for intraoral wound closure in special conditions. CLINICAL RELEVANCE: A combination of both, suturing and CTA, could be a promising option in critical soft-tissue wounds requiring high functional stability and elasticity.

Effects of throat packs in upper airway surgery under intubation anesthesia: a randomized controlled trial.

INTRODUCTION: Throat packs (TP) are used in upper airway surgery to avoid accumulation and aspiration of blood, foreign bodies, and fluids. But side effects such as sore throat and TP retention have been reported and challenge the standardized use of TP. The aim of this study is to compare benefits and side effects of TP versus no TP for upper airway procedures in intubation anesthesia. MATERIAL AND METHODS: One hundred forty-eight patients with surgical interventions at the upper airway under intubation anesthesia were included. Of those, n = 74 each were treated without (A, control) and with (B) TP. Study group B was subdivided whether TP was placed by the surgeon (B1; n = 37) or by the anesthesiologist (B2; n = 37). TP-related side effects such as sore throat, foreign body sensation, hoarseness, dyspnea, difficulty of swallowing, nausea, retching, nausea, aspiration, and pneumonia as well as the influence of TP design and the applicant (surgeon or anesthetist) were analyzed. RESULTS: A significantly increased rate of difficulty of swallowing (p = 0.045), intensity of sore throat (p = 0.04), and foreign body sensation (p = 0.024) was found in group B when compared to group A. There was no correlation between hoarseness, dyspnea, nausea, retching, and TP. No case of aspiration or pneumonia was seen but one TP was accidentally forgotten in the patient. B2 showed an increased frequency of difficulty swallowing, followed by A and B1. B1 led to the highest incidence of nausea followed by the A and B2. CONCLUSION: The use of TP led to a high rate of side effects without showing the propagated advantages. CLINICAL RELEVANCE: The use of TP must be considered critically and cannot generally be recommended without specific reasons, such as high aspiration risk.

3D printing in oral and maxillofacial surgery: a nationwide survey among university and non-university hospitals and private practices in Germany.

OBJECTIVES: Oral and maxillofacial surgery (OMFS) has undergone pioneering progress through the development of three-dimensional (3D) printing technologies. The aim of this study was to evaluate the use of 3D printing at OMFS university and non-university hospitals and private practices in Germany. MATERIALS AND METHODS: For explorative assessment, a dynamic online questionnaire containing 10-22 questions about the current use of 3D printing and the reasons behind it was sent to OMFS university and non-university hospitals and private practices in Germany by the study group from the German Association of Oral and Maxillofacial Surgery (DGMKG). RESULTS: In total, 156 participants responded from university (23 [14.7%]) and non-university hospitals (19 [12.2%]) and private practices without (85 [50.5%]) and with 29 (18.6%) inpatient treatment facility. Highest applications of 3D printing were in implantology (57%), microvascular bone reconstructions (25.6%), and orthognathics (21.1%). Among the participants, 37.8% reportedly were not using 3D printing. Among the hospitals and private practices, 21.1% had their own 3D printer, and 2.5% shared it with other departments. The major reason for not having a 3D printer was poor cost efficiency (37.6%). Possessing a 3D printer was motivated by independence from external providers (91.3%) and rapid template production (82.6%). The preferred printing methods were stereolithography (69.4 %) and filament printing (44.4%). CONCLUSIONS: OMFS 3D printing is established in Germany with a wide range of applications. CLINICAL RELEVANCE: The prevalence of 3D printing in hospitals and private practices is moderate. This may be enhanced by future innovations including improved cost efficiency.

The influence of the SARS-CoV-2 pandemic on oral and maxillofacial surgery: a nationwide survey among 54 hospitals and 240 private practices in Germany.

OBJECTIVE: The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic has created hitherto unknown challenges for healthcare systems and patient care. This study aimed to analyze its influence on patient care and healthcare management in oral and maxillofacial surgery (OMFS) in Germany. MATERIALS AND METHODS: A nationwide survey of the German Association of Oral and Maxillofacial Surgery was performed. Individual questionnaires containing 10 questions for university as well as non-university hospitals and 15 questions for private practices (PPs) for OMFS were created to collect data for patient numbers and surgical procedures conducted, usage of personal protection equipment (PPE), SARS-CoV-2 tests, and economic aspects. RESULTS: Fifty-four hospitals and 240 PPs participated in the study. The reduction in ward capacities and number of surgical procedures ranged from 17 to 78%. PPE consisted of standard surgical masks (58% hospitals, 64% PPs) and FFP2/N95/KN95 respirators (45% hospitals, 48% PPs). Preoperative SARS-CoV-2 tests were more frequently performed in hospitals (34% vs 2%). At PPs, turnover for medical and dental procedures billed to the public insurance had reduced to 58.81% and 62.43%, respectively, of the corresponding values for 2019, and 58.75% of the PPs had applied for short-time allowances. CONCLUSION: With the exception of some elective procedures, primary patient care in OMFS has been assured during the pandemic. However, the immense economic burden on hospitals and PPs cannot be conclusively assessed at this point. CLINICAL RELEVANCE: For OMFS, the German healthcare system has shown the ability to adapt to emergency situations such as the SARS-CoV-2 pandemic. Adequate surgical capacities in OMFS are necessary even during pandemics.

Clinical efficacy of an antibody-based detection system for human papilloma virus infection in oral squamous cell carcinoma.

OBJECTIVES: There is an increasing number of oral squamous cell carcinoma (OSCC) associated with HPV-16. However, p16 expression by immunohistochemistry as the current gold standard for a surrogate marker for virus infection reveals unsatisfying diagnostic accuracy. The aim of this study was to investigate a new rapid test for L1 antibody detection (Prevocheck®) and to validate its diagnostic performance. MATERIALS AND METHODS: In a prospective study, the HPV 16 association of all consecutive patients with an OSCC treated between 2015 and 2019 were analyzed by L1 seropositivity (via PrevoCheck®), p16 immunostaining, and partly multiplex PCR for subtype analysis. RESULTS: Overall (n = 107), p16 expression was positive in 17 cases (15.9%), and L1 antibody seropositivity in 7 cases (6.5%). In PCR analysis, two cases of HPV35 and 50 were found. Total HPV prevalence was 8.4% overall and 6.5% for HPV-16. An inferior diagnostic accuracy for HPV-16-associated OSCC in comparison to PrevoCheck® was revealed. CONCLUSION: The rapid test for L1 antibodies showed an optimal sensitivity and specificity, positive and negative predictive value, and an overall diagnostic accuracy of 100%. However, HPV prevalence seems low in OSCC. CLINICAL RELEVANCE: L1 rapid test may represent an additional diagnostic staging method to detect HPV-16 association rather than p16 immunohistochemistry.

How is neck dissection performed in Oral and Maxillofacial Surgery? Results of a representative nationwide survey among university and non-university hospitals in Germany.

INTRODUCTION: Neck dissection (ND) is a surgical procedure addressing cervical lymph nodes and metastases in patients with oral squamous cell carcinoma (OSCC). The aim of this study was to analyze clinical decisions regarding indications and variations of ND in Oral and Maxillofacial Surgery (OMFS) in Germany. MATERIAL AND METHODS: A nationwide survey of the German Association of Oral and Maxillofacial Surgery was performed using dynamic online questionnaires including 38 questions. Data about oncological centers, case numbers, and staging procedures were collected. Relevant aspects, such as inclusion of level IIb and levels IV and V to ND, uni- vs. bilateral ND, and the influence of extra-nodal extension (ENE) of metastases on extension of ND were evaluated. RESULTS: Eighty-four OMFS of university and non-university hospitals participated in the study (responding rate 21.4%). Sixty-six (78.57%) stated to work at certified cancer centers and 53.57% of the hospitals treated between 50 and 100 OSCC cases per year. CT and/or MRI of the head and neck was performed in most of the staging procedures. Level IIb was included by 71 (93.42%) of the participants in selective ND. Levels IV and V were included by 53 (69.74%) in node-positive neck. In solitary ipsilateral metastases (ENE-), 49 participants (62.82%) stated to perform exclusively an ipsilateral ND and 40 (51.95%) stated to perform only an ipsilateral ND in ENE+. CONCLUSION: This study demonstrated a high rate of certified cancer centers in Germany showing differences regarding staging procedures, indications, and extension of ND, especially in increasingly complex cases. CLINICAL RELEVANCE: Clinical decisions regarding ND are dependent on case-individual aspects and must be decided individually.

Treatment Modalities of Recurrent Oral Mucosal Melanoma In Situ.

Oral mucosal melanoma (OMM) represents an extremely rare entity that is associated with a poor prognosis due to late diagnosis and early metastasis. Here, extensive surgical therapy is the therapy of choice. In contrary, for OMM in situ, the respective therapeutical recommendations are lacking. In this case report, treatment modalities of an OMM in situ of the palate, including the maxillary alveolar process, are reported. The tumor relapsed twice despite adequate surgical therapy and reconstruction. Therefore, irradiation was performed as an adjuvant therapy. At a follow-up of two years, the patient was free from recurrences.

Biofunctionalization of porcine-derived collagen matrices with platelet rich fibrin: influence on angiogenesis in vitro and in vivo.

OBJECTIVES: Porcine-derived collagen matrices (CM) can be used for oral tissue regeneration, but sufficient revascularization is crucial. The aim of this study was to analyze the influence of platelet-rich fibrin (PRF) on angiogenesis of different CM in vitro and in vivo. MATERIALS AND METHODS: Three different CM (mucoderm®, jason®, collprotect®) were combined with PRF in a plotting process. Growth factor release (VEGF, TGF-ß) was measured in vitro via ELISA quantification after 1,4 and 7 days in comparison to PRF alone. In ovo yolk sac (YSM) and chorion allantois membrane (CAM) model, angiogenic potential were analyzed in vivo with light- and intravital fluorescence microscopy after 24 h, then verified with immunohistochemical staining for CD105 and αSMA. RESULTS: Highest growth factor release was seen after 24 h for all three activated membranes in comparison to the native CM (VEGF 24 h: each p < 0.05; TGF-ß: each p < 0.001) and the PRF (no significant difference). All activated membranes revealed a significantly increased angiogenic potential in vivo after 24 h (vessels per mm2: each p < 0.05; branching points per mm2: each p < 0.01; vessel density: each p < 0.05) and with immunohistochemical staining for CD105 (each p < 0.01) and αSMA (each p < 0.05). CONCLUSIONS: PRF improved the angiogenesis of CM in vitro and in vivo. CLINICAL RELEVANCE: Bio-functionalization of CM with PRF could easily implemented in the clinical pathway and may lead to advanced soft tissue healing.

Influence of clodronate and compressive force on IL-1ß-stimulated human periodontal ligament fibroblasts.

OBJECTIVES: The aim of this study was to investigate in vitro the effect of clodronate on interleukin-1ß (IL-1ß)-stimulated human periodontal ligament fibroblasts (HPdLFs) with the focus on inflammatory factors of orthodontic tooth movement with and without compressive force. MATERIALS AND METHODS: HPdLFs were incubated with 5 µM clodronate and 10 ng/mL IL-1ß. After 48 h, cells were exposed to 3 h of compressive force using a centrifuge. The gene expression of cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), matrix metalloproteinase 8 (MMP-8), and the tissue inhibitor of MMP (TIMP-1) was analyzed using RT-PCR. Prostaglandin E2 (PGE-2), IL-6, and TIMP-1 protein syntheses were quantified via ELISA. RESULTS: Compressive force and IL-1ß induced an overexpression of COX-2 gene expression (61.8-fold; p < 0.05 compared with control), diminished by clodronate (41.1-fold; p < 0.05 compared with control). Clodronate slowed down the compression and IL-1ß induced IL-6 gene expression (161-fold vs. 85.6-fold; p < 0.05 compared with control). TNF-α was only slightly affected without statistical significance. Clodronate reduced IL-1ß-stimulated MMP-8 expression with and without compressive force. TIMP-1 on gene and protein level was downregulated in all groups. Analyzing the MMP-8/TIMP-1 ratio, the highest ratio was detected in IL-1ß-stimulated HPdLFs with compressive force (21.2-fold; p < 0.05 compared with control). Clodronate diminished IL-1ß-induced upregulation of MMP-8/TIMP-1 ratio with (11.5-fold; p < 0.05 compared with control) and without (12.5-fold; p < 0.05 compared with control) compressive force. CONCLUSION: Our study demonstrates a slightly anti-inflammatory effect by clodronate under compressive force in vitro. Additionally, the periodontal remodeling presented by the MMP-8/TIMP-1 ratio seems to be diminished by clodronate. CLINICAL RELEVANCE: Reduction of pro-inflammatory factors and reduction of periodontal remodeling might explain reduced orthodontic tooth movement under clodronate intake.

Influence of buffy coat-derived putative endothelial progenitor cells on tumor growth and neovascularization in oral squamous cell carcinoma xenografts.

OBJECTIVES: The aim of this murine in vivo study was to investigate whether buffy coat-derived putative endothelial progenitor cells (BCEPC) alter tumor growth and neovascularization in oral squamous cell carcinomas (OSCC). MATERIALS AND METHODS: A murine xenograft model using the PCI-13 oral cancer cell line was deployed of which n = 24 animals received 2 × 106 BCEPC by transfusion whereas the control group (n = 24) received NaCl (0.9%) instead. Tumor size, volume, and capillary density were determined by sonography and measurement with a caliper. Immunohistochemical analysis was carried out with antibodies specific for Cytokeratins, Flt-4, Podoplanin, and Vimentin. RESULTS: In the experimental group, systemic application of BCEPC significantly increased tumor volume to 362.49% (p = 0.0012) and weight to 352.38% (p = 0.0018) as well as vascular densities to 162.15% (p = 0.0021) compared with control tumors. In addition, BCEPC-treated xenografts exhibited higher Cytokeratin expression levels by a factor of 1.47 (p = 0.0417), Podoplanin by a factor of 3.3 (p = 0.0020) and Vimentin by a factor of 2.5 (p = 0.0001), respectively. CONCLUSIONS: Immunohistochemical investigations support the notion that BCEPC transfusion influences neovascularization and lymphatic vessel density, thereby possibly promoting tumor progression. Future studies, which will include gene expression analysis, should help to define the possible role of BCEPC during OSCC progression in more detail. CLINICAL RELEVANCE: Endothelial progenitor cells (EPCs) could serve as a target structure for the treatment of OSCC and possibly other solid tumors.

Vascular architecture in free flaps: Analysis of vessel morphology and morphometry in murine free flaps.

The aim of this study was to analyze the development of vascular architecture as well as vascular morphometry and morphology of anastomosed microvascular free flaps. Free pectoral skin flaps were raised in 25 rats and anastomosed to the femoral vessels in the groin region. CD31 immunohistology was performed after 3, 7 and 12 d (each 5 animals each) to analyze microvessel density (MVD), microvessel area (MVA) and microvessel size (MVS). Microvascular corrosion casting was performed after 7 and 12 d (5 animals each) to analyze vessel diameter (VD), intervascular distance (IVD), interbranching distance (IBD), and branching angle (BA). Further on, sprout and pillar density as hallmarks of sprouting and intussusceptive angiogenesis were analyzed. Pectoral skin isles from the contralateral side served as controls. A significantly increased MVD was found after 7 and 12 d (p each <0.001). MVA was significantly increased after 3, 7 and 12 d (p each <0.001) and a significantly increased MVS was analyzed after 3 and 7 d (p each <0.001). VD and IVD were significantly increased after 7 and 12 d (p each <0.001). For IBD, a significantly increase was measured after 7 d (p < 0.001). For IBA, sprout and pillar density, no significant differences were found (p each ≥0.05). Significant changes in the vascular architecture of free flaps after successful microvascular anastomosis were seen. Since there was no evidence for sprout and pillar formation within the free flaps, the increased MVD and flap revascularization might be induced by the receiving site.

Biofunctionalization of porcine-derived collagen matrix using enamel matrix derivative and platelet-rich fibrin: influence on mature endothelial cell characteristics in vitro.

OBJECTIVES: The present study evaluated the effect of an enamel matrix derivative (EMD) and platelet-rich fibrin (PRF)-modified porcine-derived collagen matrix (PDCM) on human umbilical vein endothelial cells (HUVEC) in vitro. MATERIALS AND METHODS: PDCM (mucoderm®) was prepared to 6 mm (±0.1 mm) diameter discs. PDCM samples were incubated with either EMD, PRF, or control solutions for 100 min at 4 °C before the experiments. Cell-inducing properties of test materials on HUVEC cells were tested with cell proliferation assays (MTT, PrestoBlue®), a cytotoxicity assay (ToxiLight®), a Boyden chamber migration assay, and a cell attachment assay. Scanning electron microscopy (SEM) imaging was performed to determine the surface and the architecture of the modified matrices. RESULTS: Cell proliferation was elevated in the EMD and PRF groups compared with control (p each ≤0.046). PRF modification increased HUVEC migration ability by 8-fold compared with both control and EMD groups (p each <0.001). Both treatments significantly promoted the cell attachment of HUVEC to PDCM, as assessed by direct cell counts on the matrices (p each <0.001). CONCLUSIONS: HUVEC cell characteristics were overall improved by EMD- and PRF- modified PDCM. Adsorbed bioactive molecules to the PDCM surface may have contributed to a more preferable environment to surrounding cells. CLINICAL RELEVANCE: The results may give evidence that PDCM modification with EMD or PRF, respectively, might be a useful approach to improve clinical outcomes, to prevent inflammatory reactions and wound-healing disturbances, and to expand the clinical application area of PDCM.

Effects of an oral bisphosphonate and three intravenous bisphosphonates on several cell types in vitro.

OBJECTIVE: To analyze the influence of an oral bisphosphonate and compare the potency to intravenous bisphosphonates on various cell types as regards the rarity of bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) caused by oral bisphosphonate. MATERIALS AND METHODS: A viability assay (MTT), a migration assay (Boyden chamber), and an apoptosis assay (Caspase-Glo® 3/7) were performed to analyze the effect of bisphosphonates on human fibroblasts, umbilical vein endothelial cells (HUVEC), and osteoblasts. RESULTS: Alendronate and intravenous bisphosphonates suppressed cell viability and migration, and induced apoptosis in all tested cell types. Alendronate had a greater impact than ibandronate on the characteristics in fibroblasts and osteoblasts but not as strong as zoledronate. CONCLUSIONS: The incidence of BP-ONJ in oral bisphosphonate treatment is reported to be much lower than that in intravenous bisphosphonates. However, the influences of alendronate on human cells were at least as strong as ibandronate, although it was lower than zoledronate. CLINICAL RELEVANCE: Alendronate showed strong enough effects to suppress human somatic cells and was comparable to certain intravenous bisphosphonates in potency. This study suggests that the lower incidence of BP-ONJ in alendronate treatment is not originated by its potency, but might be due to the low bioavailability of alendronate, lower dosing on a daily basis, and having no additional therapies.

Mechanical loading increases pro-inflammatory effects of nitrogen-containing bisphosphonate in human periodontal fibroblasts.

OBJECTIVES: There is increasing evidence that inflammation and biomechanical loading can influence the effects of bisphosphonates (BP). The aim of this study was to investigate the influence of tensile strain application combined with IL-1ß and clodronate or zoledronate on human periodontal ligament fibroblasts (HPdLF) in vitro. MATERIALS AND METHODS: HPdLF were cultured with 10 nM IL-1ß and 5 µM clodronate or zoledronate for 48 h. Cells were applied to cyclic tensile strain (CTS; 3% elongation) for 12 h in vitro. Cell number was analyzed directly after CTS by MTT assay. Gene expression of receptor activator of cyclooxygenase-2 (COX-2) was investigated using real-time PCR. MMP-8, TIMP-1, and PGE2 were measured by ELISA. Statistics were performed with SPSS (ANOVA, p < 0.05). RESULTS: Zoledronate reduced the cell number of HPdLF (60.3 vs. 100%), which was significant when combined with IL-1ß. Combined with 3% CTS, this effect was voided and cell number increased over the level of the control cells. IL-1ß led to a 10-fold increase of COX-2 gene expression. Combined with CTS and zoledronate, this increase was enhanced to a gene expression 70-fold that of control cells with related PGE2 synthesis. Clodronate neither reduce the cell number nor enhanced the COX-2 gene expression. CTS increased MMP-8 protein synthesis. Combined with BP, this increase was voided. TIMP-1 protein synthesis was increased at all conditions under CTS. CONCLUSIONS: Mechanical loading might activate cell metabolism and abolish BP- and inflammation-induced reduction of viability. Combination of mechanical loading, inflammation, and nitrogen-containing bisphosphonates can cause pro-inflammatory effects. CLINICAL RELEVANCE: Periodontal inflammation should be treated initially before BP intake to prevent decreased cell viability of the periodontium and increased inflammation, which might be enhanced by the addition of mastication forces.

Comparative metabolic analysis in head and neck cancer and the normal gingiva.

OBJECTIVES: Chronic accumulation of lactate in malignant tumor tissue is associated with increased malignancy and radioresistance. For this study, biopsies of primary head and neck squamous cell carcinoma (HNSCC) and of the normal gingiva of the same patient were compared via metabolic profiling to the healthy gingiva from cancer-free patients. MATERIALS AND METHODS: Cryobiopsies of 140 HNSCC patients were used to determine ATP, lactate, and glucose concentrations of the tumor and normal gingiva via induced metabolic bioluminescence imaging (imBI). Additionally, these metabolites were quantified in a collective of 79 healthy (non-tumor-bearing) patients. Furthermore, tumor samples were analyzed via immunofluorescence imaging and quantitative real-time PCR for the expression of lactate and glucose transporters. RESULTS: There were significant differences in ATP concentrations detectable between the tumor, normal gingiva of tumor patients, and gingiva from healthy patients. Lactate concentrations were significantly increased in tumor tissue compared to the normal gingiva of tumor patients as well as the gingiva from healthy patients. Concerning glucose, there was a significant decrease in glucose concentrations detectable in the tumor biopsies compared to the normal gingiva of tumor patients. On the other hand, tumor samples from patients revealed significantly elevated relative expression levels of monocarboxylate transporters (MCT-1 and MCT-4), as well as glucose transporters (GLUT-1 and GLUT-3) compared to the corresponding normal gingiva of each patient. CONCLUSIONS: We could demonstrate that the lactate concentration in HNSCC correlates with primary tumor (T) stage. CLINICAL RELEVANCE: The aim of this study was to identify metabolic parameters to improve early cancer diagnosis, allow predictions on the degree of malignancy, and contribute to a personalized tumor therapy.

Diabetes and hyperglycemia as risk factors for postoperative outcome in maxillofacial surgery.

BACKGROUND: Aim of this study was to investigate the frequency of complications in maxillofacial surgery in-patients in correlation to diabetes mellitus or a pathologically altered glucose metabolism. MATERIALS AND METHODS: All patients' electronic health records were analyzed retrospectively. Diabetes mellitus anamnesis, the treatment regime, blood glucose levels, and the duration of inpatient treatment were recorded. Glucose readings ≥200 mg/dL measured at any time and fasting glucose levels of ≥110 mg/dL were defined as hyperglycemic. Noted complications were infection, dehiscence, swelling, and necrosis. RESULTS: 8.7% out of 1374 patients had a known diabetes diagnosis. 13.0% had high fasting glucose and 11.4% aberrant maximum glucose readings. Complications did not occur more often in patients with a previously known diabetes but more often in patients with high maximum blood glucose levels. Of these patients, only 56.3% were known diabetics. CONCLUSIONS: Diabetes mellitus does not necessarily lead to higher frequency of complications in surgical patients. Moreover, patients with well-controlled diabetes seem to have a similar outcome compared to nondiabetics. Hyperglycemia however has an important impact on treatment outcome.

Significance of endothelial progenitor cells (EPC) for tumorigenesis of head and neck squamous cell carcinoma (HNSCC): possible marker of tumor progression and neovascularization?

OBJECTIVES: Angiogenesis and neovascularisation plays a crucial role for tumorigenesis and tumor progression in head and neck squamous cell carcinoma (HNSCC). The aim of our study was to investigate the neovascularization capacity by endothelial progenitor cells (EPC) in tumor patient as a possible predictor for tumor progression and tumor stage. MATERIALS AND METHODS: Therefore, we investigated the cell number and biologic activity by cell migration and colony-forming ability of EPC. Cells were isolated from the peripheral venous blood of 79 patients who suffer HNSCC in different stages of disease. Thirty-three healthy individuals served as the control group. RESULTS: Significantly increased biological activities were reflected by expression of the migration rate (1027 ± 1510) in comparison to the control group (632 ± 269) and the clonal potency measured by colony-forming unit (CFU) (tumor patients (19.7 ± 12.3) vs. control group (10.84 ± 4.8)). To determine whether or not EPC number can be used as a valid prognostic marker for clinical outcome of tumor patients, we furthermore compared a "high EPC-number-subgroup" (HI) with a "low EPC-number-subgroup" (LO) in a Kaplan-Meier survival curve. The HI-subgroup shows herein clearly a worse outcome. CONCLUSIONS: Our findings indicate a possible pathway for EPC to play a critical role in the vasculogenesis and consequently in the progression of HNSCC. CLINICAL RELEVANCE: Our findings could serve as possible predictors for the neovascularisation potential in HNSCC tumor patients.