This study analyzed the human maxilla to support the development of mean-value-based cutting guide systems for maxillary reconstruction, bridging the gap between freehand techniques and virtual surgical planning (VSP). This retrospective cohort study used routine CT scans. DICOM data enabled 3D modelling and the maxilla was divided into four regions: paranasal (R1), facial maxillary sinus wall (R2), zygomatic bone (R3) and alveolar process (R4). Surface comparisons were made with a reference skull. Statistical analyses assessed anatomical variations, focusing on mean distance (Dmean), area of valid distance (AVD), integrated distance (ID) and integrated absolute distance (IAD). The study addressed hemimaxillectomy defects for two-segmental reconstructions using seven defined bilateral points to determine segmental distances and angles. Data from 50 patients showed R2 as the most homogeneous and R4 as the most heterogeneous region. Significant age and gender differences were found in R3 and R4, with younger patients and females having more outliers. Cluster analysis indicated that males had R1 and R3 positioned anterior to the reference skull. The mean angle for segmental reconstruction was 131.24° ± 1.29°, with anterior segment length of 30.71 ± 0.57 mm and posterior length of 28.15 ± 0.86 mm. Anatomical analysis supported the development of semistandardized segmental resection approaches. Although gender and anatomical differences were noted, they did not significantly impact the feasibility of mean-value-based cutting-guide systems. This study provides essential anatomical data for creating cost-effective and efficient reconstruction options for maxillary defects, potentially improving surgical outcomes and expanding reconstructive possibilities beyond current techniques.

Objectives Fibula free flaps (FFF) are the standard approach to mandibular reconstruction after partial resection, with the goal of restoring aesthetics and masticatory function. The graft position affects both and must be carefully selected. Correlations between sagittal positioning and upper airway anatomy are known from orthognathic surgery. This study aims to evaluate changes in mandibular position and upper airway anatomy after reconstructive surgery with FFF and corresponding correlations.Materials and methods Mandibular position after reconstruction was evaluated using three-dimensional datasets of pre- and postoperative computed tomography scans of patients treated between 2020 and 2022. Three-dimensional measurements were performed on both condyles and the symphyseal region. Changes in upper airway volume and minimum cross-sectional area (minCSA) were analysed. Intra-rater reliability was assessed. Correlations between changes in upper airway anatomy and sagittal mandibular position were tested.Results The analysis included 35 patients. Intra-rater reliability was good to excellent. Condylar deviations and rotations were mostly rated as small. Changes in symphyseal position were considerably greater. Median airway volume decreased in the oropharynx and hypopharynx. Posterior deviation of the symphysis was associated with a decreasing minCSA in the hypopharynx and vice versa.Conclusions The overall accuracy of mandibular reconstructions with FFF is high, but there is room for optimization. The focus of research should be extended from masticatory to respiratory rehabilitation.Clinical relevance Effects on respiratory function should be considered prior to graft positioning. The clinical relevance of upper airway changes within the complex rehabilitation of reconstructive surgery patients needs to be further investigated.

Background In reconstructive surgery, improvements are needed in the effective teaching of free flap surgery. There is a need for easily accessible and widely available training without high financial costs or ethical concerns while still providing a realistic experience. Our aim was to develop an appropriate training model for microvascular flaps.Methods We identified pig head halves as most appropriate regarding availability, cost, and realism. These accrue largely by the food industry, so no animals need to be sacrificed, making it more ethical from an animal welfare perspective. We evaluated the suitability as flap donor site and analyzed the vascular anatomy of 51 specimens.Results Anatomical evaluation revealed a reliable and constant vascular anatomy, allowing the design of a flap model that can effectively illustrate the entire process of microvascular flap surgery. The process was divided into 6 key steps. The flap can be harvested after marking the vascular pedicle 5.3 cm from the lateral corner of the mouth. Skin island design and subsequent tissue dissection follow until a fasciocutaneous flap is raised, similar to a radial flap. Upon completion of flap harvesting, it can be freely transferred for defect reconstruction. Microvascular anastomosis can be performed on recipient vessels in the cervical region, and the difficulty can be individually adjusted.Conclusions The developed training model is a reasonable compromise in terms of surgical realism, availability, didactic value, and cost/time effectiveness. We believe it is a powerful and effective tool with high potential for improving surgical education and training.

OBJECTIVES:Confocal laser endomicroscopy (CLE) is an optical method that enables microscopic visualization of oral mucosa. Previous studies have shown that it is possible to differentiate between physiological and malignant oral mucosa. However, differences in mucosal architecture were not taken into account. The objective was to map the different oral mucosal morphologies and to establish a "CLE map" of physiological mucosa as baseline for further application of this powerful technology. MATERIALS AND METHODS:The CLE database consisted of 27 patients. The following spots were examined: (1) upper lip (intraoral) (2) alveolar ridge (3) lateral tongue (4) floor of the mouth (5) hard palate (6) intercalary line. All sequences were examined by two CLE experts for morphological differences and video quality. RESULTS:Analysis revealed clear differences in image quality and possibility of depicting tissue morphologies between the various localizations of oral mucosa: imaging of the alveolar ridge and hard palate showed visually most discriminative tissue morphology. Labial mucosa was also visualized well using CLE. Here, typical morphological features such as uniform cells with regular intercellular gaps and vessels could be clearly depicted. Image generation and evaluation was particularly difficult in the area of the buccal mucosa, the lateral tongue and the floor of the mouth. CONCLUSION:A physiological "CLE map" for the entire oral cavity could be created for the first time. CLINICAL RELEVANCE:This will make it possible to take into account the existing physiological morphological features when differentiating between normal mucosa and oral squamous cell carcinoma in future work.

The anatomically complex and often spatially restricted conditions of anastomosis in the head and neck region cannot be adequately reproduced by training exercises on current ex vivo or small animal models. With the development of a Realistic Anatomical Condition Experience (RACE) model, complex spatial-anatomical surgical areas and the associated intraoperative complexities could be transferred into a realistic training situation in head and neck surgery. The RACE model is based on a stereolithography file generated by intraoperative use of a three-dimensional surface scanner after neck dissection and before microvascular anastomosis. Modelling of the acquired STL file using three-dimensional processing software led to the model's final design. As a result, we have successfully created an economical, sustainable and realistic model for microsurgical education and provide a step-by-step workflow that can be used in surgical and general medical education to replicate and establish comparable models. We provide an open source stereolithography file of the head-and-neck RACE model for printing for educational purposes. Once implemented in other fields of surgery and general medicine, RACE models could mark a shift in medical education as a whole, away from traditional teaching principles and towards the use of realistic and individualised simulators.

Background: Maxillofacial osteosarcoma (MOS) is a rare disease, mostly located to the mandible or maxilla. Surgical resection with wide free margins represents the key intervention to achieve favorable prognosis. MOS are particularly demanding to resect and surgically reconstruct because of the numerous tissue types and functions included in this location. Case reports: We introduce two patients with a highly malignant maxillary OS treated by primary tumor resection and immediate reconstruction with a microvascular soft tissue flap. After confirmation of relapse-free tissue healing and sufficiently free resection margins, osseous reconstruction was performed in a second operation by use of a virtually planned microvascular Fibula Flap. Both patients received implant-supported dental rehabilitation and show relapse-free for seven and three years, respectively. Conclusions: Combination of radical tumor resection, primary soft tissue reconstruction and secondary bone reconstruction allows high oncologic safety and optimal conditions for a thoroughly planned osseous as well as dental rehabilitation.

We aimed to validate the metric accuracy of a 3-dimensional (3D) facial scanner (FS) and an intraoral scanner (IOS) in capturing the nasolabial region in ex vivo unilateral cleft lip and palate (UCLP) models. The nasolabial region of 10 UCLP models was scanned using a 3D FS as well as an IOS and a previously validated stationary 3D scanner as a reference. Intraoral scan was performed directly on the UCLP models. In order to apply the FS on the models, they were embedded in a 3D printed sample face. Both test groups were aligned to the reference by applying a section-based best-fit algorithm. Subsequent analysis of the metric deviation from the reference was performed with a 3D analysis tool. Mean distance and integrated distance served as main parameters for surface and volume comparison. Point comparison served as an additional parameter. Statistical analysis was carried out using t-test for unconnected samples. Considering mean distance and integrated distance as main parameters for 3D evaluation of the scanner's accuracy, FS and IOS differ significantly in their metric precision in scanning the cleft model compared to the reference. The IOS proved to be significantly more accurate than the FS compared to the previously described stationary 3D scanner as reference and validated baseline. Further validation of the tested IOS and FS for 3D assessment of the nasolabial region is presented by adding the previously validated ATOS III Triple Scan blue light scanner as a reference. The IOS shows, compared to a validated baseline scan, significantly higher metric precision in experimental cleft model scanning. The collected data provides a basis for clinical application of the IOS for 3D assessment of the nasolabial region.

Background Intraoral soft tissue deficiency and impaired wound beds are common problems after cleft and tumour surgery or after dental trauma. Frequently, limited defects are overtreated with extensive microvascular reconstruction procedures, but pedicled flaps remain useful, as they are simple to harvest, and they provide a reliable outcome. The buccal flap, first described in the 1970s, has been used for palatine lengthening in cleft patients over decades. In the following, we present an expanded indication in cases of palatal fistula, complex vestibulum, exposed bone in orthognathic surgery, and osteoradionecrosis. Methods We conducted a retrospective chart review and report on all buccal flaps harvested in our department within the last 3 years with a follow-up period of at least half a year after flap surgery. Patients of all age groups and treatment indications in which a buccal flap was used were implicated in the evaluation. Results Sixteen buccal flaps were performed in 10 patients. The median age at the time of surgery was 42 years, reaching from 12 up to 66 years. Fourteen buccal flaps were used for upper jaw or palatal coverage; two buccal flaps were used in the mandible. In terms of complications (four flaps; 25%), there were two partial flap failures, one wound dehiscence and one wound dehiscence. There were no failures of the remaining mucosal flap islands after pedicle dissection. Conclusion The buccal flap is a reliable and straightforward approach to challenging intraoral wound beds with soft tissue deficiency. We thoroughly discuss the additional indications for buccal flap surgery, describe the harvest technique, and provide strategies to prevent intra- and postoperative complications.

Background: The involvement of immune cell infiltration and immune regulation in the progression of oral squamous cell carcinoma (OSCC) is shown. Anti-PD-1 therapy is approved for the treatment of advanced OSCC cases, but not all patients respond to immune checkpoint inhibitors. Hence, further targets for therapeutic approaches are needed. The number of identified cellular receptors with immune checkpoint function is constantly increasing. This study aimed to perform a comparative analysis of a large number of immune checkpoints in OSCC in order to identify possible targets for therapeutic application. Materials and Methods: A NanoString mRNA analysis was performed to assess the expression levels of 21 immune regulatory checkpoint molecules in OSCC tissue (n = 98) and healthy oral mucosa (NOM; n = 41). The expression rates were compared between the two groups, and their association with prognostic parameters was determined. Additionally, relevant correlations between the expression levels of different checkpoints were examined. Results: In OSCC tissue, significantly increased expression of CD115, CD163, CD68, CD86, CD96, GITRL, CD28 and PD-L1 was detected. Additionally, a marginally significant increase in CD8 expression was observed. BTLA and PD-1 levels were substantially increased, but the differential expression was not statistically significant. The expression of CD137L was significantly downregulated in OSCC compared to NOM. Correlations between immune checkpoint expression levels were demonstrated, and some occurred specifically in OSCC tissue. Conclusions: The upregulation of inhibitory receptors and ligands and the downregulation of activators could contribute to reduced effector T-cell function and could induce local immunosuppression in OSCC. Increased expression of activating actors of the immune system could be explained by the increased infiltration of myeloid cells and T-cells in OSCC tissue. The analysis contributes to the understanding of immune escape in OSCC and reveals potential targets for oral cancer immunotherapy.

Defects in head and neck regions are standardly treated with microvascular grafts, such as free scapular (SFF) and fibular flaps (FFF), which are subject to a certain amount of bone resorption over time. The aim of this study was the 3-dimensional evaluation of bone resorption volume in both grafts. Over a period of 10 years, computed tomograms (CT) of patients with mandibular reconstructions with SFFs and FFFs were examined. The respective grafts were segmented as well as 3-dimensionally measured. Furthermore, factors such as gender, age, nicotine abuse, previous disease with type 2 diabetes, and adjuvant therapies, were examined for their influence. A total of 211 CT scans from 67 patients (40 SFFs and 27 FFFs) were included in the study. SFFs showed slightly higher median bone volumes (87.60% at 730 days and 86.55% at 1500 days) than FFFs (84.40% at 730 days and 82.10% at 1500 days). When final volumes were considered, FFFs had higher mean volume values (88.22%) than SFFs (83.82%), with significant correlation between resorption volume and time progression (r = 0.357, p = 0.024). All previously mentioned factors had no significant effect on bone resorption. Bone volumes of FFFs showed postoperative volume reductions similar to those of SFFs, with isolated SFFs having markedly lower volume values. The choice of a microvascular graft for reconstruction in the mandible proves difficult regarding bone resorption. The presented results may support decisions about future transplantations.

BackgroundPrognosis of patients with recurrent or metastatic head and neck cancer is generally poor. Adjuvant immunotherapy (IT) featuring immune checkpoint inhibition (ICI) is standard of care in advanced stage head and neck squamous cell carcinoma (HNSCC) and cutaneous squamous cell carcinoma (CSCC). ICI response rates in CSCC are described as higher than in HNSCC. IT is constantly shifting into earlier disease stages which confronts the surgeon with immunotherapeutically pre-treated patients. It is therefore becoming increasingly difficult to assess which patients with symptomatic tumor disease and a lack of curative surgical option might benefit from salvage surgery.Case presentationsThe following 6 cases describe therapeutic decision-making regarding ICI and (salvage) surgery in patients with advanced stage HNSCC or CSCC. Cases A and B focus on neoadjuvant ICI followed by salvage surgery. In Cases C and D salvage surgery was performed after short-term stabilization with partial response to ICI. The last two cases (Cases E and F) address the surgical approach after failure of ICI. All cases are discussed in the context of the current study landscape and with focus on individual decision-making. For better understanding, a timetable of the clinical course is given for each case.ConclusionsICI is rapidly expanding its frontiers into the neoadjuvant setting, frequently confronting the surgeon with heavily pretreated patients. Salvage surgery is a viable therapeutic concept despite the rise of systemic treatment options. Decision-making on surgical intervention in case of a salvage surgery remains an individual choice. For neoadjuvant ICI monitoring regarding pathological tumor response or tumor necrosis rate, we suggest correlation between the initial biopsy and the definite tumor resectate in order to increase its significance as a surrogate marker. Scheduling of neoadjuvant ICI should be further investigated, as recent studies indicate better outcomes with shorter time frames.

Summary: Free flap monitoring and early detection of malperfusion are a central aspect in reconstructive surgery. Warm ischemia, measured as the time a certain tissue is able to survive without any additional medical or thermal treatment, ranges from hours in muscle and nerval tissue up to days in bony tissue. Hence, meticulous flap monitoring is essential to discover early signs of malperfusion and decide upon timely re-intervention. Besides clinical examination techniques and Doppler sonography, a multitude of mostly experimental procedures are available to evaluate free flap perfusion. Particularly in older patients, the assessment of the skin island in microvascular grafts is a demanding task because the natural loss of elasticity, the reduction of subcutaneous tissue, and the decrease in water content limit the visibility of capillary filling and favor hematomas. We report a case of a 90-year-old woman with an extensive cutaneous squamous cell carcinoma of the right zygomatic and lateral orbital region without any locoregional or distant metastasis. Due to the resilient health status, we decided for a surgical approach with consecutive microvascular radial forearm flap reconstruction. On account of the difficult assessment of elderly skin after microvascular transplantation, we decided on additional flap monitoring by thermal heat imaging during the operation and aftercare. This case report discusses the successful application of thermal heat imaging in a clinical non-assessable free flap and discusses the application of dynamic infrared thermography as a monitoring tool in microvascular free flap surgery.

Objectives Mandibular reconstruction after segmental mandibulectomy can be challenging without virtual surgical planning and osteotomy guides. The purpose of this study was to analyze anatomic parameters to facilitate the evaluation of ideal fibula wedge osteotomies to reconstruct the neomandibula in a simple and cost-effective manner without the need for preoperative virtual planning. Materials and methods Computed tomography scans were acquired from randomly selected patients, and all images were obtained from routine clinical diagnostics, e.g., tumor staging, or preoperatively before reconstruction. Data was used to calculate stereolithographic models of the mandible for length and angle measurements. Statistical analysis was performed ( p < 0.05). Results CT scans of 100 patients were analyzed: 39 were female and 61 were male patients, mean age was 59.08a. The mandibular arch angle proved to be constant with 241.07 ± 2.39°. The outside B-segment length was 80.05 ± 5.16 mm; the anterior S-segment length was 27.69 ± 3.16 mm. The angle of the mandibular arch showed differences in means ( p = 0.004) between age groups, but effect was proved low. No relevant statistical significances were detected. Conclusions The development of a mandible reconstruction template tool would benefit the majority of head and neck patients, which is due to a constant mandibular arch angle and symphysis segment length throughout the general patient population, allowing the mimicking of a harmonic mandibular arch with up to three fibula segments. Clinical relevance The developed mandible reconstruction template tool can facilitate the fibula wedge osteotomies necessary for reconstruction of an ideal neomandibula providing a novel approach which is simple and cost-effective.

INTRODUCTION:The authors developed a semi-standardised resection and cutting guide for mandibular reconstruction with free fibula flap based on data of mandible sizes and angles.METHODS:After analyzing the angles and lengths of mandibular angles and segments on computer tomography, a partly-adjustable resection guide for the mandible and cutting guide for the fibula were designed.RESULTS:After testing and optimizing the guides on plastic models and cadavers, the guides were successfully used for mandible resection and reconstruction with free fibula flap in 8 patients with segmental mandibulectomy. Application of the cutting and resection guides and functional results like occlusion and aesthetic appearence were satisfactory in all cases.CONCLUSIONS:The developed semi-standardised device is a helpful instrument for facilitating reconstruction of segmental mandibular defects with free fibula flaps. No extensive preoperative preparation and 3D printing is necessary which can avoid additional costs for virtual planning. Especially for lower budget health systems this can be an alternative to virtual planning.

PurposeElective neck dissection (END) is a common primary treatment strategy for oral tongue squamous cell carcinoma (OTSCC), although uncertainty remains regarding the necessary extent of END for strictly unilateral early stage OTSCC. The authors evaluated two END variations, unilateral and bilateral, to determine the optimal extent.Materials and methodsA retrospective cohort study was performed on patient data from two departments of oral and maxillofacial surgery. All previously untreated patients from both clinics who were diagnosed with early-stage (pT1-2) unilateral OTSCC were included. The following variables were collected: age, gender, END type/extent, tumor localization, later nodal metastasis, and TNM status. Statistical analyses were performed (p < 0.05).ResultsA total of 150 patients were identified, 105 receiving unilateral END and 45 bilateral END. The rates of postoperative positive lymph nodes were 21.9% for ipsilateral END and 26.7% for bilateral END (bilateral END: all positive nodes ipsilateral). In all, 14 patients in the ipsilateral group developed nodal metastasis during tumor aftercare (11 patients ipsilateral, 3 patients contralateral neck). In the bilateral group, nodal metastasis was later observed in 4 cases (8.9%; 3 cases ipsilateral, 1 case contralateral neck). Statistical analysis could not detect significant differences between the END procedures.ConclusionAs both procedures lead to similar results in preventing or omitting possible later nodal metastasis, the two methods seem to be valuable alternatives. In conclusion, we recommend bilateral END because of advantages with regard to oncologic safety and esthetic outcome, but the decision for END should always be according to the patient's general health status, comorbidities, and individual tumor risk profile.

Orbital exenteration (OE) is considered to be a mutilating surgical procedure reserved for relentlessly progressive neoplastic disorders or extensive facial trauma with unfavourable eye involvement. Malignant tumours, accounting for the majority of ablative orbital surgeries, may be caused by primary orbital tumours or secondarily by neoplasias from the surrounding skin, the maxillary sinus or intracranial malignomas. Orbital exenteration following trauma is mostly caused by penetrating globe defects or extended infections with the danger of intracranial effects. Thoughtful resection planning, the exploitation of reconstructive possibilities as well as the consideration of adjuvant therapy are essential to provide the patient with the best available treatment. As a multitude of reconstructive procedures exist, it is of crucial importance to offer a disease-tailored treatment to achieve a successful patient outcome. After retrospective analysis of 45 orbital exenteration cases within the last decade, we developed a defect-driven classification for ablative orbital therapy followed by a guideline for reconstructive procedures. The classification as well as the reconstruction guideline will help the surgeon to restore anatomic boundaries and to promote physiological and psychological recovery for the patient.

INTRODUCTION:Advanced non-melanocytic skin cancer (NMSC) in the facial region causes extensive tissue loss, possibly coverable by local flaps. Remote free flaps are the reconstructive method of choice, despite disadvantages such as color and texture mismatch, and bulkiness with regard to facial skin.MATERIAL AND METHODS:Post-ablative facial NMSC defects in four patients were reconstructed using remote free flaps, including radial forearm, scapular, parascapular, and anterolateral thigh flaps. Four months later, a split-thickness skin graft (STSG) was acquired from the retroauricular region to generate a non-cultured autologous epidermal cell (NCAEC) suspension. The flap surfaces were de-epithelialized, and the NCAEC suspension was sprayed onto the flap surface to improve the mismatch between facial and flap color. Debulking was also carried out. The aesthetic outcome was examined by photography and clinical examination 3, 6, 9, and 12 months after the first operation.RESULTS:All flaps survived the 11- to 21-month follow-up. The secondary operation was accompanied by a delay in re-epithelialization in one case. No STSG donor-site problems occurred. Follow-up photographs showed significant improvements in the color and texture of the flaps.CONCLUSIONS:Facial reconstruction with a free flap results in a mismatch of color and texture. Secondary correction of the flap surface by de-epithelialization and NCAEC application significantly improves the aesthetic outcome.

Radiation-induced fibrosis (RIF) is one of the severe long-term side effects of radiation therapy (RT) with a crucial impact on the development of postoperative wound healing disorders (WHD). The grades of fibrosis vary between mild to severe depending on individual radiosensitivity. In this study, we have investigated the molecular pathways that influence RIF and have correlated data from immunohistochemistry (IHC) for von –Willebrand Factor (vWF) and from Real-Time Polymerase Chain Reaction (RT-PCR) concerning markers such as Transforming Growth Factor (TGF)-β 1, and vWF, with clinical data concerning the occurrence of WHD during follow-up.

INTRODUCTION:Cleft lip and palate (CLP) defects are considered to be the most common facial birth defect. Despite the relevance of this global health issue, the knowledge level on CLP is alarmingly low. Therefore, it was our aim to construct a realistic haptic anatomic CLP model that can be used for 3-dimensional visualizing CLP and practicing the first steps of CLP treatment.METHODS:Models of newborns with CLP are not commercially available so far. Therefore, construction was based on a purchased baby doll of a healthy newborn. After fabrication of the model, we used it in a hands-on course for medical students. A total of 138 students were asked to perform practical tasks such as like taking intraoral impressions and fixating drinking and nasoalveolar plates on the CLP model. To evaluate the didactic benefit, preteaching and postteaching multiple-choice tests were performed.RESULTS:A suitable patient's plaster model from our archive served as a template for shaping a unilateral CLP in the face of a baby doll by means of a scalpel and a handheld rotating milling machine. Hard and soft palate were milled out and replaced by a hard stone cast of a patient with cleft palate. When analyzing the preteaching and postteaching scores of the students' multiple-choice tests, an improvement was achieved in 69.6%, which proved to be statistically significant (P < 0.001).CONCLUSIONS:In our opinion, the CLP model is a useful teaching tool with a high potential to improve the level of knowledge and practical expertise in the field of CLP.

PURPOSE:Following its renaissance in ophthalmology during the 1990s, preserved human amniotic membrane (HAM) has become an attractive biomaterial for all surgical disciplines. This article reviews the current and potential use of HAM in oral and maxillofacial surgery, its postulated properties and common preservation techniques.METHODS:Literature was identified by an electronic search of PubMed in July 2012; this was supplemented from the reference lists of the consulted papers.RESULTS:HAM has been used in the field of oral and maxillofacial surgery from 1969 onwards because of its immunological preference and its pain-reducing, antimicrobial, mechanical and side-dependent adhesive or anti-adhesive properties. The effects of HAM on dermal and mucosal re-epithelialisation have been highlighted. Typically, HAM is applied after being banked in a glycerol-preserved, DMSO-preserved or freeze-dried and irradiated state. Whereas the use of HAM in flap surgery and in intra-oral and extra-oral lining is reported frequently, novel HAM applications in post-traumatic orbital surgery and temporomandibular joint surgery have been added since 2010. Tissue engineering with HAM is a fast-expanding field with a high variety of future options.CONCLUSIONS:Preserved HAM is considered to be a safe and sufficient biomaterial in all fields of oral and maxillofacial wound healing. Recently published novel indications for HAM application lack a high level of evidence and need to be studied further.