Prevention of perioperative venous thromboembolic complications using pneumatic compression cuffs in oral cancer patients in maxillofacial surgery.

OBJECTIVES: Venous thromboembolism (VTE) is still considered to be a significant medical issue. Physical measures to prevent perioperative venous thrombosis include early mobilization and intermittent pneumatic compression (IPC). The aim of this study was to evaluate whether IPC can reduce the incidence of postoperative thromboembolic events in patients with oral squamous cell carcinoma (OSCC) undergoing maxillofacial surgery. MATERIALS AND METHODS: Between March 2020 and May 2021, 75 patients with OSCC who did not receive perioperative prophylaxis using IPC were retrospectively examined to determine the occurrence of postoperative thromboembolism. Accordingly, 79 patients who received perioperative thrombosis prophylaxis using an IPC system as part of surgical tumor therapy from May 2021 to September 2023 were included in the study. The primary outcome measure was the occurrence of postoperative thromboembolism. RESULTS: In the control group without IPC, thromboembolic events were observed in five out of 75 patients during postoperative hospitalization. In the intervention group, no thromboembolic occurrences were identified among the 79 patients studied (p = 0.02). The mean Caprini score in the control group was 7.72, whereas in the intervention group it averaged 8.30 (p = 0.027). CONCLUSIONS: The implementation of IPC-devices as supplementary perioperative thrombosis prophylaxis resulted in a notable decrease in postoperative venous thromboembolism (Number Needed to Treat = 15), which is why implementation of the system as a regular part of the clinical routine for perioperative management of OSCC patients can be considered a sensible approach. CLINICAL RELEVANCE: The use of IPC enhances patient outcomes and may lead to improved postoperative care protocols in this high-risk patient population.

The impact of the COVID-19 pandemic on the dental-maxillofacial emergency service of a German university hospital in the year 2020.

OBJECTIVES: COVID-19 is considered one of the most serious pandemic in history and has posed major challenges to the world's health care. Dentistry and oral and maxillofacial surgery (CMFS) are particularly affected due to direct exposure to the respiratory tract, as the reservoir of SARS-CoV-2. In this study, the impact of the COVID-19-pandemic on a dental and CMFS emergency services in Germany in 2020 was first time investigated and correlated with governmental restriction measures in public life. MATERIALS AND METHODS: Epidemiological data of a German University Hospital were analysed from a total of 8386 patients in 2019 and 2020. Parameters included information on demographics, time, weekday and reason for presentation, as well as diagnosis and therapy performed. Data from 2020 were compared with those from 2019, taking into account the nationwide periods of public life restrictions. RESULTS: In 2020, 22% fewer patients presented via dental and CMFS emergency service. In a monthly comparison, there were negative peaks of up to - 41% in November, but also a plus of 26% in July. The largest decreases were recorded during the lockdown periods in spring (- 33%) and winter (- 39%). Further, a threefold increase in actual emergencies and inpatient admissions revealed during these time periods (p < 0.001). CONCLUSIONS: COVID-19 pandemic had a significant impact on the dental and CMFS emergency service in 2020 resulting in more severe cases. CLINICAL RELEVANCE: This study underlines the importance of maintaining an emergency service system and basic outpatient care in these specialities, which requires uniform recommendations from the medical-dental societies and politics.

Differences in the expression of caveolin-1 isoforms in cancer-associated and normal fibroblasts of patients with oral squamous cell carcinoma.

OBJECTIVES: For many years, tumor development has been viewed as a cell-autonomous process; however, today we know that the tumor microenvironment (TME) and especially cancer-associated fibroblasts (CAFs) significantly contribute to tumor progression. Caveolin-1 (Cav-1) is a scaffolding protein which is involved in several cancer-associated processes as important component of the caveolae. Our goal was to shed light on the expression of the two different isoforms of Cav-1 in normal fibroblasts (NFs) and CAFs of patients with oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: Fibroblasts from normal mucosa and CAFs were isolated and propagated in vitro. Gene expression of the different Cav-1 isoforms was assessed via quantitative real-time PCR (qPCR) and supplemented by protein expression analysis. RESULTS: We could show that the Cav-1ß isoform is more highly expressed in NFs and CAFs compared to Cav-1α. Furthermore, the different Cav-1 isoforms tended to be differently expressed in different tumor stages. However, this trend could not be seen consistently, which is in line with the ambiguous role of Cav-1 in tumor progression described in literature. Western blotting furthermore revealed that NFs and CAFs might differ in the oligomerization profile of the Cav-1 protein. CONCLUSION: These differences in expression of Cav-1 between NFs and CAFs of patients with OSCC confirm that the protein might play a role in tumor progression and is of interest for further analyses. CLINICAL RELEVANCE: Our findings support a possible role of the two isoforms of Cav-1 in the malignant transformation of OSCC.

Hyperspectral analysis for perioperative perfusion monitoring-a clinical feasibility study on free and pedicled flaps.

OBJECTIVES: In reconstructive surgery, flap monitoring is crucial for early identification of perfusion problems. Using hyperspectral imaging (HSI), this clinical study aimed to develop a non-invasive, objective approach for perfusion monitoring of free and pedicled flaps. MATERIAL AND METHODS: HSI of 22 free (FF) and 8 pedicled flaps (PF) in 30 patients was recorded over time. Parameters assessed were tissue oxygenation/superficial perfusion (0-1 mm) (StO2 (0-100%)), near-infrared perfusion/deep perfusion (0-4 mm) (NIR (0-100)), distribution of haemoglobin (THI (0-100)), and water (TWI (0-100)). Measurements up to 72 h were correlated to clinical assessment. RESULTS: Directly after flap inset, mean StO2 was significantly higher in FF (70.3 ± 13.6%) compared with PF 56.2 ± 14.2% (p = 0.05), whereas NIR, THI, and TWI were similar (NIR_p = 0.82, THI_p = 0.97, TWI_p = 0.27). After 24 h, StO2, NIR, THI, and TWI did not differ between FF and PF. After 48 h, StO2, NIR, and TWI did not differ between FF and PF whereas THI was significantly increased in FF compared with PF(p = 0.001). In three FF, perfusion decreased clinically and in HSI, 36(1), 40(2), 5(3), and 61(3) h after flap inset which was followed by prompt intervention. CONCLUSIONS: StO2 < 40%, NIR < 25/100, and THI < 40/100 indicated arterial occlusion, whereas venous problems revealed an increase of THI. In comparison with FF, perfusion parameters of PF were decreased after flap transfer but remained similar to FF later on. CLINICAL RELEVANCE: HSI provides objective and non-invasive perfusion monitoring after flap transplantation in accordance to the clinical situation. With HSI, signs of deterioration can be detected hours before clinical diagnosis.

Dynamic contrast-enhanced magnetic resonance imaging for monitoring neovascularization during bone regeneration-a randomized in vivo study in rabbits.

OBJECTIVES: Micro-computed tomography (µ-CT) and histology, the current gold standard methods for assessing the formation of new bone and blood vessels, are invasive and/or destructive. With that in mind, a more conservative tool, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), was tested for its accuracy and reproducibility in monitoring neovascularization during bone regeneration. Additionally, the suitability of blood perfusion as a surrogate of the efficacy of osteoplastic materials was evaluated. MATERIALS AND METHODS: Sixteen rabbits were used and equally divided into four groups, according to the time of euthanasia (2, 3, 4, and 6 weeks after surgery). The animals were submitted to two 8-mm craniotomies that were filled with blood or autogenous bone. Neovascularization was assessed in vivo through DCE-MRI, and bone regeneration, ex vivo, through µ-CT and histology. RESULTS: The defects could be consistently identified, and their blood perfusion measured through DCE-MRI, there being statistically significant differences within the blood clot group between 3 and 6 weeks (p = 0.029), and between the former and autogenous bone at six weeks (p = 0.017). Nonetheless, no significant correlations between DCE-MRI findings on neovascularization and µ-CT (r =-0.101, 95% CI [-0.445; 0.268]) or histology (r = 0.305, 95% CI [-0.133; 0.644]) findings on bone regeneration were observed. CONCLUSIONS: These results support the hypothesis that DCE-MRI can be used to monitor neovascularization but contradict the premise that it could predict bone regeneration as well.

Catalogue of Interactive Learning Objectives to improve an Integrated Medical and Dental Curriculum.

INTRODUCTION: Online learning media are increasingly being incorporated into medical and dental education. However, the coordination between obligatory and facultative teaching domains still remains unsatisfying. The Catalogue of Interactive Learning Objectives of the University Clinic of Mainz (ILKUM), aims to offer knowledge transfer for students while being mindful of their individual qualifications. Its hierarchical structure is designed according to the Association for Dental Education in Europe (ADEE) levels of competence. MATERIALS AND METHODS: The ILKUM was designed to establish a stronger interconnection between already existing and prospective learning strategies. All contents are linked to the current lectures as well as to e-learning modules, e.g., clinical case studies and OR videos. Students can conduct self-examinations regarding specific learning objectives. Since 2007, ILKUM has been developed and analyzed regarding its acceptance among dental students. RESULTS: These improved e-learning techniques foster time and location-independent access to study materials and allow an estimation of the knowledge achieved by students. Surveys of our students clearly show a large demand for upgrading ILKUM content (89%; n = 172) with integrated self-testing (89%; n = 174). In parallel to the advancement of our e-learning offering, a portion of internet-based learning is constantly rising among students. CONCLUSION: The broad acceptance and demand for the development of ILKUM show its potential. Moreover, ILKUM grants fast, topic-oriented querying of learning content without time and locale limitations as well as direct determination of the individually needed knowledge conditions. CLINICAL SIGNIFICANCE: The long-term goal of the ILKUM project is to be a sustainable, important additional modality of teaching and training for dental and medical students.

Antimicrobial effect of Australian antibacterial essential oils as alternative to common antiseptic solutions against clinically relevant oral pathogens.

BACKGROUND: The aim of the study was to examine the in vitro antibacterial activity of different oils in comparison to antiseptics against oral microorganisms. METHODS: The antimicrobial effect of tea tree oil (TTO), eucalyptus oil (EO), lemon grass oil (LGO), and a eucalyptus-based oil mixture (MXT) were tested in comparison to chlorhexidine digluconate (CHX), povidone-iodine (BTA), and octenidine dihydrochloride (OCT). Oral bacterial strains and candida species using the agar diffusion test were used for the antimicrobial study. RESULTS: All tested oils showed antimicrobial potency against the tested biological indicators. In comparison of all tested substances the largest effective zones were measured for LGO, followed from MXT and CHX. TTO and EO were less effective against the tested microorganisms followed from BTA. CONCLUSIONS: The results of this study show that some essential oils have better antimicrobial properties than standard oral antiseptics. In a follow-up step, the ideal concentrations, the composition of essential oils, and the mode of application will be evaluated. The antibacterial efficacy of essential oils might be promising for use in clinical and oral hygiene applications. The cost reduction and availability particularly in rural areas with easy access to the originating plants might be advantageous factors to be considered.

A chemiluminescent light system in combination with toluidine blue to assess suspicious oral lesions-clinical evaluation and review of the literature.

OBJECTIVES: The aim of the study was an evaluation of an acetic acid wash and chemiluminescent light system in combination with toluidine blue in order to detect visual identified, potentially malignant lesions. MATERIALS AND METHODS: Forty-four patients with 50 oral lesions of primary uncertain visible dignity were included. Next to a clinical examination, a screening with ViziLite® (VL) as well as toluidine blue (TB; together ViziLite® Plus (VLP)) was conducted. Histopathology served as gold standard and sensitivity (SE), specificity (SP), positive as well as negative predictive value (PPV, NPV) was calculated descriptively. Additionally, a PubMed literature search using the key words "ViziLite" and "chemiluminescence oral cancer" was conducted. RESULTS: Histological diagnosis showed 40 lesions of reactive/inflammatory nature, moderate dysplasia (n = 3) and oral squamous cell carcinoma (OSCC n = 7). All OSCCs and one dysplasia were identified correct via clinical diagnosis (SE 90 %, SP 100 %, PPV 100 %, NPV 97.5 %). VL examination could show all malignancies with low specificity (SE 100 %, SP 30 %, PPV 26 %, NPV 100 %). TB and VLP were positive in all cases of cancer and in one case of inflammation (SE 80 %, SP 97.5 %, PPV 89 %, NPV 95 %). In the review, eight clinical trials with similar results were included. CONCLUSIONS: The adjunct of TB to VL reduces the number of false positives without increasing the rate of false negatives. CLINICAL RELEVANCE: Clinical evidence to justify the additional cost of the system for diagnosis of suspicious lesions is weak. However, for the potential role of VLP in detection of lesions not otherwise identified in the visual exam in general dental practice further studies are required.

Clinical efficacy of a computerised device (STA™) and a pressure syringe (VarioJect INTRA™) for intraligamentary anaesthesia.

INTRODUCTION: To evaluate the impact of experience whilst using different devices for intraligamentary anaesthesia, dental students tested clinical anaesthetic efficacy of a mechanical (PDL-S) and a computer-controlled (CCLAD) application system in restorative patients. MATERIAL AND METHODS: In a prospective study, 41 Patients in need of restorative treatment in lower posterior mandible were randomised into three groups (PDL-S: teeth n = 22; CCLAD: teeth n = 20; inferior alveolar nerve block (IANB): teeth n = 20). Dental last year students conducted anaesthesia and dental treatment. Primary objectives were differences in pain during treatment [numeric rating scale (NRS)] as well as in anaesthetic efficacy (complete/sufficient vs. insufficient/no effect) between PDL-S and CCLAD. Pain of injection, need for second injections, amount of anaesthetic solution and duration of local numbness were assessed. IANB as gold standard was compared to each system descriptively. RESULTS: PDL-S had a significant lower pain during treatment (P = 0.017) but a similar anaesthetic efficacy (P = 0.175) compared to the CCLAD system. Concerning pain of injection (P = 0.42), quantity of second injections (P = 0.232), amount of used solution (P = 0.073) as well as duration of local numbness (P = 0.253), no differences were seen. When comparing both periodontal ligament injection (PDL)-systems with IANB, pain rating was higher when using CCLAD. Injection pain, amount of used solution as well as soft tissue anaesthesia was less for PDL-S and CCLAD. DISCUSSION: Both PDL techniques showed a good success for dental routine treatments. Although, compared to the mechanic device, the CCLAD system might need more clinical daily experience. CONCLUSION: We recommend including specific trainings in intraligamentary anaesthesia in the dental curriculum.

Periodontal intraligament injection as alternative to inferior alveolar nerve block--meta-analysis of the literature from 1979 to 2012.

OBJECTIVES: In a first meta-analysis, inferior alveolar nerve block (IANB) and periodontal intraligamentary injection anesthesia (ILA) were compared with focus on the failure rate of local anesthesia, pain during injection, additional injections, cardiovascular disturbances (CVD), and method-inherent differences (unwanted side effects, latency time, amount of anesthetic solution, duration of anesthesia) in adult patients. MATERIALS AND METHODS: Prospective and retrospective studies with clinical comparison of both injection techniques considering the relevant outcome parameters in adult patients from 1979 to 2012 were included. A specific tool for assessing risk of bias in each included study was adopted. Data were assessed for methodological reliability and extracted and supplemented by sensitivity analysis by two independent reviewers. RESULTS: Seven studies were included [evidence grade Ib (n=1), IIb (n=3), and III (n=3)]. For other parameter than CVD, the significant heterogeneity of the random effects did not allow the reporting of pooled summary effect estimates. CVD were found significantly more often after IANB [odds ratio (OR): 0.12 (0.02-0.69)]. Further analysis revealed less injection pain in cases of ILA [OR: 0.32 (0.1-1)]. For failure rates as well as for needed additional injections, no significant differences were detected. IANB showed a latency of >3 min, whereas ILA had nearly none. The effect of IANB is longer than for ILA. CONCLUSIONS: Methodological and reporting flaws were consistently observed in the included articles. Except for CVD, it could not be shown that ILA is neither superior nor inferior compared to IANB. CLINICAL RELEVANCE: IANB as "gold standard" for routine dental treatments should be discussed.

Cervical metastases of squamous cell carcinoma of the maxilla: a retrospective study of 25 years.

OBJECTIVES: Squamous cell carcinomas (SCCs) of the maxilla are relatively rare; therefore, only little data is available regarding the frequency of cervical metastasis (CM) and therapy strategies. Most authors only undertake clinical observation of the lymph nodes. The aim of this retrospective study was to evaluate the manner of metastasis in SCC of the maxilla. MATERIALS AND METHODS: All patient records from 1987 to 2011 were scanned for SCC of the maxilla. Patients with SCC limited to the maxilla were comprised. The cases were analyzed regarding tumor node metastasis staging system and any special occurrences in the follow-up time such as tumor recurrence, metastasis, and exitus letalis. Classification and staging were performed according to the 2003 UICC system. RESULTS: One hundred thirty-eight patients were comprised of 36 % females and 64 % males (average age, 66 years; women, 71 years; men, 63 years). The average follow-up time was 43 months (range, 0-195). Fifty-eight percent smoked or declared regular consumption of alcohol. About 50 % of the patients had an advanced tumor stage (III-IV). At the time of the primary diagnosis, 38 % of the patients had CM. There is an increased risk for CM occurrence with increasing tumor size and grading and a tumor localized in the postcanine region. Contralateral CM arises frequently in T4 tumors and tumors localized in the postcanine region. CONCLUSION: The data exhibit aggressive regional metastatic behavior of SCC of the maxilla. CLINICAL RELEVANCE: Therefore, surgical treatment of the draining lymphatic system as a primary management strategy is recommended for patients with SCC of the maxilla.

Oral rehabilitation with dental implants in irradiated patients: a meta-analysis on implant survival.

OBJECTIVES: The aim of this comprehensive literature review is to provide recommendations and guidelines for dental implant therapy in patients with a history of radiation in the head and neck region. For the first time, a meta-analysis comparing the implant survival in irradiated and non-irradiated patients was performed. MATERIAL AND METHODS: An extensive electronic search in the electronic databases of the National Library of Medicine was conducted for articles published between January 1990 and January 2013 to identify literature presenting survival data on the topic of dental implants in patients receiving radiotherapy for head and neck cancer. Review and meta-analysis were performed according to Preferred Reporting Items for Systematic Review and Meta-Analyses statement. For meta-analysis, only studies with a mean follow-up of at least 5 years were included. RESULTS: After screening 529 abstracts from the electronic database, we included 31 studies in qualitative and 8 in quantitative synthesis. The mean implant survival rate of all examined studies was 83 % (range, 34-100 %). Meta-analysis of the current literature (2007-2013) revealed no statistically significant difference in implant survival between non-irradiated native bone and irradiated native bone (odds ratio [OR], 1.44; confidence interval [CI], 0.67-3.1). In contrast, meta-analysis of the literature of the years 1990-2006 showed a significant difference in implant survival between non-irradiated and irradiated patients ([OR], 2.12; [CI], 1.69-2.65) with a higher implant survival in the non-irradiated bone. Meta-analysis of the implant survival regarding bone origin indicated a statistically significant higher implant survival in the irradiated native bone compared to the irradiated grafted bone ([OR], 1.82; [CI], 1.14-2.90). CONCLUSIONS: Within the limits of this meta-analytic approach to the literature, this study describes for the first time a comparable implant survival in non-irradiated and irradiated native bone in the current literature. Grafted bone combined with radiotherapy was identified as a negative prognostic factor on implant survival. CLINICAL RELEVANCE: The evolution of implant hardware and improvement of treatment strategies during the last years have affirmed dental implant-supported concepts as a valuable treatment option for patients with a history of radiation in the head and neck region.

[The new S2k AWMF guideline for the treatment of obstructive sialadenitis in commented short form]. / Die neue S2k AWMF Leitlinie zur Behandlung der obstruktiven Sialadenitis in kommentierter Kurzform.

A new and interdisciplinary S2k AWMF guideline for the treatment of obstructive sialadenitis has been published. There have been several technical achievements, for instance in the field of ultrasonography, via sialendoscopy, or by MR-sialography, that have increased the possibilities for diagnosis and treatment of patients with obstructive sialadenitis. In the past, the treatment of choice in case of unsuccessful medical treatment was a complete extirpation of the affected salivary gland. Nowadays, using a variety of modern treatment options (like sialendoscopy, or extracorporeal shock-waves lithotripsy sometimes combined with salivary duct incision), it is possible in most patients, especially in cases of sialolithiasis, to preserve the affected gland. A functional recovery after gland-sparing surgery is described but more data is needed to finally evaluate the long-time results. The new guideline describes all relevant steps to diagnose an obstructive sialadenitis and values all diagnostic tools critically. Finally, all recommendable therapy options are described and valued, too.

Changes in the quality of life in patients undergoing orthognathic therapy - A systematic review.

The aim of this study was to investigate the impact of orthognathic therapy on patients' quality of life. Therefore, a systematic review was conducted including all prospective studies that compared pretherapeutic and posttherapeutic Oral Health Impact Profile (OHIP) or Overall Quality of Life (OQOL) questionnaire scores. Studies in patients with congenital deformities, clefts, or posttraumatic or cancer-associated deformities were excluded. Overall, 23 prospective studies were included; 8 used OHIP, 9 used OQOL and 6 used both questionnaires. A total of 1039 patients were identified (60.29% women, 39.71% men), with a mean age of 45.17 years. All analyzed studies showed in both OHIP and OQLQ an improvement of the quality of life in patients after orthognathic therapy. While improved scores could be observed in all investigated criteria, the studies demonstrated that social and aesthetic aspects showed the most prominent impact. Comparison of different Angle Classes showed, furthermore, that Class III patients had an even greater advantage over those with a Class II deformity. The review confirms that the quality of life in patients with orthognathic therapy improves significantly in all observed aspects. With regard to Angle Classes, Class III patients showed an even greater improvement than Class II patients.

Associations between single-nucleotide polymorphisms of the VEGF gene and long-term prognosis of oral squamous cell carcinoma.

INTRODUCTION: Functional polymorphisms (SNPs) of the vascular endothelial growth factor (VEGF) are associated with the incidence of oral squamous cell carcinoma (OSCC). An impact of VEGF-SNPs on prognosis of OSCC patients seems possible. Therefore, correlations between prognostic parameters of OSCC patients and five VEGF-SNPs were determined. MATERIALS AND METHODS: In a retrospective long-term study, in 113 OSCC patients that underwent curative resections, five VEGF-SNPs (-1154 G/A, +405 G/C, +936 C/T, -2578 C/A, and -460 C/T) were analyzed. Associations between SNPs and prognosis (incidence of local recurrent disease, second cancer, metastases, death, total disease-free survival) were examined. RESULTS: After a mean follow-up time of 57.6 months, 32 patients had local recurrences; 15 patients had second cancer, 15 patients metastases, and 23 patients died. The mean disease-free survival was 43.1 months. A significant increased incidence of OSCC in smokers with the VEGF -2578 A/C and -460 C/T SNP was seen (each P < 0.0001). In univariate analysis, patients with advanced OSCCs (T > 2 or N > 0) together with the -1154 A/A allele had a significant worse survival and a worse disease-free survival (both P < 0.04). The same was seen for the +405 G/G SNP (both P = 0.002). In multivariate analysis, only the negative influence of the +405 G/G SNP on survival in advanced OSCCs (T > 2) could be confirmed (P = 0.002). DISCUSSION: Possible reciprocal interactions between smoking and VEGF-SNP function were observed. Multivariate analysis confirmed the VEGF +405 G/G genotype to be associated with poor survival in advanced OSCCs; a further use of this haplotype as biomarker has to be discussed.

Influence of a collagen membrane and recombinant platelet-derived growth factor on vertical bone augmentation in implant-fixed deproteinized bovine bone--animal pilot study.

OBJECTIVES: Combinations of bone substitute block materials with membrane techniques as well as with growth factors are possible options to enhance the prognosis of vertical bone augmentation. Therefore, the aim of the pilot study was to compare the influence of a collagen membrane and a signal protein (rhPDGF-BB) on vertical bone augmentation with a stable fixed block material (deproteinized bovine bone [DBB]). MATERIALS AND METHODS: In 12 rabbits, a DBB-block was implant-fixed on the tibia in a split-leg-design. Included were: DBB only (control), DBB + collagen membrane (test), DBB + rhPDGF-BB (test) and DBB + rhPDGF-BB + collagen membrane (test). 24 samples were examined after 3 (n = 12) and 6 weeks (n = 12). Calculated parameters were new bone area (NBA;%), new vertical bone height (VBH; mm). Due to the pilot character of this study, single values are shown descriptively only. RESULTS: After 3 weeks, there were constant higher NBA values in the rhPDGF-BB-group without membrane (NBA (%) DBB: 30/16/4; DBB + membrane: 25/17/7, DBB + rhPDGF-BB: 40/33/34, DBB + rhPDGF-BB + membrane: 0/30/16; VBH (mm) DBB: 1.2/1.2/1, DBB + membrane: 0.7/0.9/1, DBB + rhPDGF-BB: 0.7/0.9/1, DBB + rhPDGF-BB + membrane: 0/1.1/1). After 6 weeks, both membrane groups showed a constant higher NBA and VBH independent to the use of rhPDGF-BB (NBA DBB: 3/0/5, DBB + membrane: 20/35/31, DBB + rhPDGF-BB: 5/8/4, DBB + rhPDGF-BB + membrane: 31/35/40; VBH DBB: 0.3/0.3/0.6, DBB + membrane: 1.6/2.4/2.1, DBB + rhPDGF-BB: 0.4/0.7/0.8, DBB + rhPDGF-BB + membrane: 1.8/2/1.8). CONCLUSIONS: For vertical augmentation, the addition of rhPDGF-BB to DBB-blocks may increase early bone growth. In the later phase, the use of a collagen membrane enhances new bone volume and height to a significant greater extend. Even if the results are higher than those in the non-membrane groups, the low gain of bone after the short time periods still needs improvement.

Steam-sterilized and degradable fused filament fabrication-printed polylactide/polyhydroxyalkanoate surgical guides for dental implants: Are they accurate enough for static navigation?

Three-dimensional (3D) printing is a rapidly evolving field and has gained increasing importance in the medical sector. However, the increasing usage of printing materials is accompanied by more wastages. With a rising awareness of the environmental impact of the medical sector, the development of highly accurate and biodegradable materials is of great interest. This study aims to compare the accuracy of polylactide/polyhydroxyalkanoate (PLA/PHA) surgical guides printed by fused filament fabrication and material jetted guides of MED610 in fully guided dental implant placement before and after steam sterilization. Five guides were tested in this study and each was either printed with PLA/PHA or MED610 and either steam-sterilized or not. After implant insertion in a 3D-printed upper jaw model, the divergence between planned and achieved implant position was calculated by digital superimposition. Angular deviation and 3D deviation at the base and the apex were determined. Non-sterilized PLA/PHA guides showed an angle deviation of 0.38 ± 0.53° compared to 2.88 ± 0.75° in sterile guides (P > 0.001), an offset of 0.49 ± 0.21 mm and 0.94 ± 0.23 mm (P < 0.05), and an offset at the apex of 0.50 ± 0.23 mm before and 1.04 ± 0.19 mm after steam sterilization (P < 0.025). No statistically significant difference could be shown for angle deviation or 3D offset at both locations for guides printed with MED610. PLA/PHA printing material showed significant deviations in angle and 3D accuracy after sterilization. However, the reached accuracy level is comparable to levels reached with materials already used in clinical routine and therefore, PLA/PHA surgical guide is a convenient and green alternative.

Early implant healing: promotion of platelet activation and cytokine release by topographical, chemical and biomimetical titanium surface modifications in vitro.

OBJECTIVES: Platelet releasate has been shown to promote osteogenetic cell proliferation and differentiation. Topography and chemistry of biomaterials have high impact on platelet activation. More specifically, the bioactive cell adhesive peptide sequence Arg-Gly-Asp (RGD) triggers platelet activation mediated by the α(IIb) ß(3) integrin receptor. Accordingly, topographical, chemical and biomimetical (immobilized RGD peptide) modifications of titanium (Ti) surfaces may enhance early platelet activation and bony healing of implants. Therefore, the aim of the study was to evaluate platelet activation with subsequent platelet-derived cytokine release by accordingly modified Ti surfaces. MATERIALS AND METHODS: Pre-treated (PT; mean roughness [R(a)]=0.04 µm, contact angle [CA]=91°), acid-etched (A, R(a) =0.83 µm, CA=106°), large grit-sandblasted, acid-etched (SLA, R(a) =3.2 µm, CA=109°) as well as hydrophilically modified acid-etched (modA, R(a) =0.83 µm, CA=0) and modified large grit-sandblasted, acid-etched (modSLA, R(a) =3.2 µm; CA=0°) titanium surfaces were investigated. Additionally, RGD peptides were chemically immobilized on PT, A and SLA surfaces (PT-RGD [CA=18°], A-RGD [CA=0°], SLA-RGD [CA=0°]). The different Ti surfaces were incubated with platelet concentrate of three healthy volunteers at room temperature for 15 min and for 30 min. High thrombogenous collagen served as the control group. Out of the supernatant, platelet consumption was assessed via platelet count (PC). Cytokine release was quantified via the level of platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). RESULTS: After 15 min, especially the rough SLA surface showed a strong decrease in PC and a strong increase in VEGF and PDGF levels. After 30 min, high platelet consumption as well as high levels of VEGF and PDGF were measured for unspecifically modified (modA) and especially for biomimetic, specifically modified (PT-RGD, A-RGD) surfaces, indicating a delayed effect of the surface modifications on platelet activation. DISCUSSION: Modifications of surface roughness modifications appear to influence early platelet activation and cytokine release after 15 min whereas surface chemistry modifications with increased hydrophilic properties and surface modifications via RGD peptide on plainer surfaces lead to a further, more specific promotion of platelet activation and degranulation after 30 min. The observed effect could be valuable for critical clinical situations like compromised bone sites.

Immobilisation of linear and cyclic RGD-peptides on titanium surfaces and their impact on endothelial cell adhesion and proliferation.

Functional coatings on titanium vascular stents and endosseous dental implants could probably enhance endothelial cell (EC) adhesion and activity with a shortening of the wound healing time and an increase of peri-implant angiogenesis during early bone formation. Therefore, the role of the structure of linear and cyclic cell adhesive peptides Arg-Gly-Asp (l-RGD and c-RGD) on differently pre-treated titanium (Ti) surfaces (untreated, silanised vs. functionalised with l- and c-RGD peptides) on EC cell coverage and proliferation was evaluated. After 24 h and after 3 d, surface coverage of adherent cells was quantified and an alamarBlue® proliferation assay was conducted. After 24 h, l-RGD modified surfaces showed a significantly better coverage of adhered cells than untreated titanium (p=0.01). Differences between l-RGD surfaces and silanised Ti (p=0.066) as well as between l-RGD and c-RGD surfaces (p=0.191) were not significant. After 3 d, c-RGD surfaces showed a significantly higher cell coverage than untreated Ti, silanised and l-RGD titanium surfaces (all p<0.0001). After 24 h, c-RGD modified surfaces showed significant higher cell proliferation compared to untreated Ti (p=0.003). However, there were no differences in proliferation between c-RGD and l-RGD (p=0.126) or c-RGD and silanised titanium (p=0.196). After 3 d, proliferation on c-RGD surfaces outranged significantly untreated titanium (p=0.004), silanised (p=0.001) and l-RGD surfaces (p=0.023), whereas no significant difference could be found between untreated Ti and l-RGD surfaces (p=0.54). According to these results, the biomimetic coating of c-RGD peptides on conventional titanium surfaces showed a positive effect on EC cell coverage and proliferation. We were able to show that modifications of titanium surfaces with c-RGD are a promising approach in promoting endothelial cell growth.

Bisphosphonates affect migration ability and cell viability of HUVEC, fibroblasts and osteoblasts in vitro.

OBJECTIVES: Bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) is a side effect in patients being treated with bisphosphonates. The bisphosphonates most often associated with BP-ONJ are the highly potent nitrogen-containing bisphosphonates, e.g. pamidronate or zoledronate. In terms of BP-ONJ aetiology, several theories are being discussed: inhibition of bone remodelling, effect on soft tissues, and antiangiogenic effect of bisphosphonates. The aim of this in vitro study was to investigate the effect of different potent bisphosphonates on osteoblasts, fibroblasts and human umbilicord vein endothelial cells (HUVEC). MATERIALS AND METHODS: Three nitrogen-containing bisphosphonates (ibandronate, pamidronate and zoledronate) and one non-nitrogen-containing bisphosphonate (clodronate) were compared concerning their potency on apoptosis induction (tunel), cell viability (calcein assay) and migration potency (boyden chamber) on osteoblasts, fibroblasts and HUVEC. RESULTS: The nitrogen-containing bisphosphonates, particularly pamidronate and zoledronate, affect cell viability, cell migration and the induction of apoptosis of osteoblasts, fibroblasts and HUVEC. CONCLUSIONS: These results support the theory that BP-ONJ is a multifactorially caused disease because several cell lines of the oral cavity which are responsible for integrity and wound healing are negatively affected by nitrogen-containing bisphosphonates. Perioperative interruption of bisphosphonate application during dental surgical procedures--if possible--might be feasible to promote better wound healing.