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Platelet-rich fibrin (PRF) is a blood concentrate derived from venous blood that is processed without anticoagulants by a one-step centrifugation process. This three-dimensional scaffold contains inflammatory cells and plasma proteins entrapped in a fibrin matrix. Liquid-PRF was developed based on the previously described low-speed centrifuge concept (LSCC), which allowed the introduction of a liquid-PRF formulation of fibrinogen and thrombin prior to its conversion to fibrin. Liquid-PRF was introduced to meet the clinical demand for combination with biomaterials in a clinically applicable and easy-to-use way. The aim of the present study was to evaluate, ex vivo, the interaction of the liquid-PRF constituents with five different collagen biomaterials by histological analyses. The results first demonstrated that large variability existed between the biomaterials investigated. Liquid-PRF was able to completely invade Mucograft® (MG; Geistlich Biomaterials, Wolhusen, Switzerland) and to partly invade Bio-Gide® (BG; Geistlich Biomaterials, Wolhusen, Switzerland) and Mucoderm® (MD; Botiss Biomaterials, Berlin, Germany), and Collprotect® (CP; Botiss Biomaterials, Berlin, Germany) showed only a superficial interaction. The BEGO® collagen membrane (BCM; BEGO Implant Systems) appeared to be completely free of liquid-PRF. These results were confirmed by the different cellular penetration and liquid-PRF absorption coefficient (PAC) values of the evaluated membranes. The present study demonstrates a system for loading biomaterials with a complex autologous cell system (liquid-PRF) in a relatively short period of time and in a clinically relevant manner. The combination of biomaterials with liquid-PRF may be clinically utilized to enhance the bioactivity of collagen-based biomaterials and may act as a biomaterial-based growth factor delivery system.
The permeability and inflammatory tissue reaction to Mucomaix® matrix (MM), a non- cross-linked collagen-based matrix was evaluated in both ex vivo and in vivo settings. Liquid platelet rich fibrin (PRF), a blood concentrate system, was used to assess its capacity to absorb human proteins and interact with blood cells ex vivo. In the in vivo aspect, 12 Wister rats had MM implanted subcutaneously, whereas another 12 rats (control) were sham-operated without biomaterial implantation. On days 3, 15 and 30, explantation was completed (four rats per time-point) to evaluate the tissue reactions to the matrix. Data collected were statistically analyzed using analysis of variance (ANOVA) and Tukey multiple comparisons tests (GraphPad Prism 8). The matrix absorbed the liquid PRF in the ex vivo study. Day 3 post-implantation revealed mild tissue inflammatory reaction with presence of mononuclear cells in the implantation site and on the biomaterial surface (mostly CD68-positive macrophages). The control group at this stage had more mononuclear cells than the test group. From day 15, multinucleated giant cells (MNGCs) were seen in the implantation site and the outer third of the matrix with marked increase on day 30 and spread to the matrix core. The presence of these CD68-positive MNGCs was associated with significant matrix vascularization. The matrix degraded significantly over the study period, but its core was still visible as of day 30 post-implantation. The high permeability and fast degradation properties of MM were highlighted.
(1) Background: Protruding ears are the most common auricular malformation affecting approximately 5% of the population. One common factor leading to auricular protrusion is a deficiency or total absence of the antihelix. A technique first described by Gottfried Lemperle in 2003 attempts cartilage thinning, folding, and fixation by non-absorbable mattress sutures after ventral skin incision along the ventral helical rim. (2) Methods: Retrospective analysis of patient records was performed for otoplasties according to this technique, performed between 1985 and 2014 at Agaplesion Markus Hospital in Frankfurt, Germany. All recorded complications were examined. (3) Results: A total of 912 single otoplasties were performed according to this technique from 1985 to 2014. Overall complications included 26% minor complications not requiring further surgery and 11% major complications leading to revision surgery. Within those requiring revision surgery, the most common reason was recurrence of auricular protrusion (5%), followed by suture granulomas (5%) and hematomas (2%). (4) Conclusions: Lemperle’s otoplasty technique addresses the open thinning and shaping of the antihelix through a ventral incision along the helix to prevent irregularities and possible ridges. Results show a low complication rate comparable to data found in published studies. This technique is easy to perform, safe, and avoids often seen contour irregularities of the antihelix compared to techniques with a posterior approach.
Razina pročišćenosti alogenoga koštanog bloka = Variant purification of an allogeneic bone block
(2017)
Svrha: Ovaj kratak tekst izvještava o histološkoj analizi sastava komercijalno raspoloživih alogenih koštanih blokova Maxgraft®. Materijali i metode: Na temelju objavljenih histoloških metoda prazni uzorci alogenih koštanih blokova Maxgraft® dekalcificirani su, dehidrirani i uloženi u parafin prije histološkog i histokemijskog bojenja. Nakon toga na prerezima su se procjenjivala obilježja materijala, poput strukture koštanoga matriksa i druge komponente, uključujući kolagen ili stanice/stanične ostatke. Rezultati: Uočeno je da ovi koštani blokovi imaju trabekularnu strukturu s lamelarnom podorganizacijom. Dodatno su nađeni i stanični ostatci unutar lakuna osteocita i na vanjskim površinama trabekula zajedno s ostatcima intertrabekularnog masnog i vezivnog tkiva, te kolagene strukture, vezivno-tkivne stanice i stanični ostatci. Zaključak: U skladu s dosadašnjim istraživanjima, podatci iz ovoga teksta pokazuju da neke od certificiranih tehnika pročišćavanja ne omogućuju proizvodnju alogenog materijala bez organskih stanica i tkivnih komponenata.
Introduction: To determine the esthetic outcome of implant-based reconstructions after autologous and allogeneic bone grafting.
Methods: From 2003 to 2009, 67 patients underwent alveolar ridge augmentation and were enrolled in the study, 41 meet the inclusion criteria and 31 agreed to take part in the study. Patients were 18-69 years old (mean: 49.3 ± 13.8 years), and predominantly female. Patients received bone block grafts either autologous (n = 48) (AUBB) or allografts (ABB) (n = 19). Implants were inserted 4-7 months (autografts) or 5-6 months (allografts) after bone grafting. The Pink Esthetic Score (PES) as well as radiographic and subjective assessments were employed for the outcome analysis. The PES was assessed twice within one month based on digital photographic images that were randomly rearranged between evaluations by three independent, experienced investigators.
Results: Across all observations and investigators, the average PES was 7.5 ± 2.6 without differences between implants inserted in auto- and allografted bone, respectively. Patients assessed the allograft procedures as less painful and would have repeated it more often. The intra-rater reliability was excellent (correlation coefficients 0.7-0.9). The inter-observer agreement was lower (correlation coefficients 0.6-0.8).
Conclusions: Bone grafting with ABB allografts yields equivalent results to autologous grafting, and patients appreciate the omission of bone harvesting. The PES is a reliable method but should be performed by the same individual.
Introduction: The aim of this study was to clinically assess the capacity of a novel bovine pericardium based, non-cross linked collagen matrix in root coverage.
Methods: 62 gingival recessions of Miller class I or II were treated. The matrix was adapted underneath a coronal repositioned split thickness flap. Clinical values were assessed at baseline and after six months.
Results: The mean recession in each patient was 2.2 mm at baseline. 6 Months after surgery 86.7% of the exposed root surfaces were covered. On average 0,3 mm of recession remained. The clinical attachment level changed from 3.5 ± 1.3 mm to 1,8 ( ± 0,7) mm during the observational time period. No statistically significant difference was found in the difference of probing depth. An increase in the width of gingiva was significant. With a baseline value of 1.5 ± 0.9 mm an improvement of 2.4 ± 0.8 mm after six month could be observed. 40 out of 62 recessions were considered a thin biotype at baseline. After 6 months all 62 sites were assessed thick.
Conclusions: The results demonstrate the capacity of the bovine pericardium based non-cross linked collagen matrix for successful root coverage. This material was able to enhance gingival thickness and the width of keratinized gingiva. The percentage of root coverage achieved thereby is comparable to existing techniques. This method might contribute to an increase of patient's comfort and an enhanced aesthetical outcome.
Osteocalcin, Azan and Toluidine blue staining in fibrous dysplasia and ossifying fibroma of the jaws
(2018)
Background: Fibrous dysplasia (FD) and ossifying fibroma (OF) are fibro-osseous lesions (FOLs) having several overlaps that may make final diagnosis difficult by hematoxylin and eosin (H/E) alone.
Aim: This study seeks to detect any association between Azan and Toluidine blue staining as compared with osteocalcin in FD and OF diagnosis.
Methods:Forty formalin fixed paraffin embedded (FFPE) blocks of FD and OF were prepared for Azan, Toluidine blue and osteocalcin staining. Brown staining of calcified structures was considered as positive for osteocalcin. Scoring for Azan and Toluidine blue was evaluated based on intensity and localization. Level of agreement of original and revised diagnosis was determined.
Results: Six (40%) of 15 FD were corroborated by osteocalcin. Eight cases initially diagnosed as OF were revised to FD. There were 25 OF according to H/E, and 17 (68%) were validated by osteocalcin. Measure of agreement between histology and immunohistochemistry was 0.081; p = .608. Eleven (42.3%) OF expressed strong toluidine blue staining of the intervening fibrous connective tissue stroma while only 2 (14.2%) FD showed similar staining, this difference was statistically significant [p = .001].
Conclusions: Histomorphometric analysis with Toluidine blue may reduce diagnostic errors of OF and FD.
Aim: To assess volumetric tissue changes at peri‐implantitis sites following combined surgical therapy of peri‐implantitis over a 6‐month follow‐up period.
Materials and Methods: Twenty patients (n = 28 implants) diagnosed with peri‐implantitis underwent access flap surgery, implantoplasty at supracrestally or bucally exposed implant surfaces and augmentation at intra‐bony components using a natural bone mineral and application of a native collagen membrane during clinical routine treatments. The peri‐implant region of interest (ROI) was intra‐orally scanned pre‐operatively (S0), and after 1 (S1) and 6 (S2) months following surgical therapy. Digital files were converted to standard tessellation language (STL) format for superimposition and assessment of peri‐implant volumetric variations between time points. The change in thickness was assessed at a standardized ROI, subdivided into three equidistant sections (i.e. marginal, medial and apical). Peri‐implant soft tissue contour area (STCA) (mm2) and its corresponding contraction rates (%) were also assessed.
Results: Peri‐implant tissues revealed a mean thickness change (loss) of −0.11 and −0.28 mm at 1 and 6 months. S0 to S1 volumetric variations pointed to a thickness change of −0.46, 0.08 and 0.4 mm at marginal, medial and apical regions, respectively. S0 to S2 analysis exhibited corresponding thickness changes of −0.61, −0.25 and −0.09 mm, respectively. The thickness differences between the areas were statistically significant at both time periods. The mean peri‐implant STCA totalled to 189.2, 175 and 158.9 mm2 at S0, S1 and S2, showing a significant STCA contraction rate of 7.9% from S0 to S1 and of 18.5% from S0 to S2. Linear regression analysis revealed a significant association between the pre‐operative width of keratinized mucosa (KM) and STCA contraction rate.
Conclusions: The peri‐implant mucosa undergoes considerable volumetric changes after combined surgical therapy. However, tissue contraction appears to be influenced by the width of KM.
Introduction: The treatment of carious lesions is one of the most fundamental competencies in daily dental practice. However, many commercially available training models lack in reality regarding the simulation of pathologies such as carious lesions. 3D printed models could provide a more realistic simulation. This study provides an exemplary description of the fabrication of 3D printed dental models with carious lesions and assesses their educational value compared to commercially available models in conservative dentistry.
Materials and Methods: A single-stage, controlled cohort study was conducted within the context of a curricular course. A stereolithographic model was obtained from an intraoral scan and then printed using fused deposition modelling. These models were first piloted by experts and then implemented and compared against commercial models in a conservative dentistry course. Experts and students evaluated both models using a validated questionnaire. Additionally, a cost analysis for both models was carried out.
Results: Thirteen dentists and twenty-seven 5th year dental students participated in the study. The 3D printed models were rated significantly more realistic in many test areas. In particular, the different tactility and the distinction in colour was rated positively in the 3D printed models. At 28.29€ (compared to 112.36€), the 3D printed models were exceptionally cost-efficient.
Conclusions: 3D printed dental models present a more realistic and cost-efficient alternative to commercial models in the undergraduate training of conservative dentistry.
Background: The feedback given to students plays an important role in their efficiency related to learning practical skills. In the present study, diverse feedback modalities have been investigated. Our hypothesis is that individualized and unsupervised video feedback can produce a similar learning experience as performing practical skills in an oral and maxillofacial surgery setting with conventional direct expert feedback (control group).
Methods: This prospective, randomized, controlled, and blinded study compared direct expert feedback (DEF), individualized video feedback (IVF) and unsupervised video feedback (UVF). The participants were fourth-year dental students from University Goethe in Frankfurt. The students were assigned to one of the three feedback methods (n = 20 per group) using simple randomization. All participants watched an instruction video for an interdental (‘Ernst’) ligature and periphery venous catheterization. Next, the students were video recorded performing the tasks by themselves (pre-test). Following this, every student received feedback using one of the above-mentioned feedback modalities. The participants then performed the same task again while being video recorded (post-test) to measure the acquired competence. Six weeks later, the students participated in an objective structured clinical examination (OSCE) to evaluate their long-term knowledge retention. All examiners were blinded regarding the students’ instructional approach and their affiliation in terms of the learning group.
Results: For the interdental ligature, we found significant improvements in performance in each feedback modality group between the pre-test and post-test (p < 0.001). UVF had the strongest effect on performance time. The comparison between each group in the post-test showed no significant differences between the three groups.
Conclusion: This study showed that IVF and UVF can be considered an alternative or adjunct to conventional methods (i.e. DEF) when learning procedural skills in oral and maxillofacial surgery. However, DEF showed to be the most effective method of feedback and therefore preferable in teaching.