Immunohistochemical detection of lymph node-DTCs in patients with node-negative HNSCC.

This study was performed to systematically assess the prevalence, topography and prognostic impact of disseminated tumor cells (DTCs) in lymph nodes (LN) of patients with primary, regional and distant metastasis-free head and neck squamous cell carcinoma (HNSCC) who underwent resection with elective neck dissection. From the routinely processed resection specimen, we could prospectively analyze a total of 1.137 exactly mapped LNs of 50 pN0-HNSCC patients, classified as tumor free by routine histopathology. Three immunohistochemistry (IHC) assays using antibodies directed against CK5/14, a broad spectrum of CKs (1-8, 10, 14-16 and 19), and CD44v6, respectively, were applied on 4.190 LN sections to detect DTCs. The IHC results were correlated with clinicopathologic parameters and clinical follow-up data. We detected seven micrometastases (MM) in five patients and 31 DTCs in 12 patients. Overall, 15 (30%) patients were positive for DTCs or MMs. Strikingly, the anatomical distribution of LN affected with DTCs was not random, but was dependent on the lateralization of the primary tumor and clustered significantly most proximal to the primary tumor. None of the investigated patients developed loco-regional lymphatic or distant metastasis during the mean follow-up period of 71 months. Our results reveal clinically occult tumor cell dissemination as an early and frequent event in HNSCC. Considering that higher rates of recurrences in therapeutic LN dissection concepts have been reported than in elective neck dissection strategies, our DTC-data support to perform elective neck dissections, since they appear to be effective in preventing loco-regional lymphatic recurrence from LN DTCs or MMs.

Scaffold-free microtissues: differences from monolayer cultures and their potential in bone tissue engineering.

OBJECTIVES: Cell-based therapies for bone augmentation after tooth loss and for the treatment of periodontal defects improve healing defects. Usually, osteogenic cells or stem cells are cultivated in 2D primary cultures, before they are combined with scaffold materials, even though this means a loss of the endogenous 3D microenvironment for the cells. Moreover, the use of single-cell suspensions for the inoculation of scaffolds or for the direct application into an area of interest has the disadvantages of low initial cell numbers and susceptibility to unwanted cellular distribution, respectively. MATERIALS AND METHODS: We addressed the question whether an alternative to monolayer cultures, namely 3D microtissues, has the potential to improve osteogenic tissue engineering and its clinical outcome. RESULTS: By contrast, to monolayer cultures, osteogenic differentiation of 3D microtissues is enhanced by mimicking in vivo conditions. It seems that the osteogenic differentiation in microtissues is enhanced by strong integrin-extracellular matrix interaction and by stronger autocrine BMP2 signaling. Moreover, microtissues are less prone to wash out by body fluids and allow the precise administration of large cell numbers. CONCLUSION: Microtissue cultures have closer characteristics with cells in vivo and their enhanced osteogenic differentiation makes scaffold-free microtissues a promising concept in osteogenic tissue engineering. CLINICAL RELEVANCE: Microtissues are particularly suitable for tissue engineering because they improve seeding efficiency of biomaterials by increasing the cell load of a scaffold. This results in accelerated osteogenic tissue formation and could contribute to earlier implant stability in mandibular bone augmentation.

Tissue expanders for soft tissue reconstruction in the head and neck area--requirements and limitations.

OBJECTIVES: The repair of skin defects in the head and neck region still poses a significant problem for many clinicians. Tissue expansion is described as a treatment option providing good color, texture, and thickness match of the expanded skin. Unfortunately, the complication rates for tissue expansion range from 0 to 48 %. Therefore, the purpose of this study was to investigate risk factors for the use of tissue expanders in head and neck reconstructions. MATERIALS AND METHODS: Forty-nine patients with skin deficits in the head and neck area underwent tissue expansion. Sixty-two implanted expanders were analyzed regarding the various complications and the success rate. RESULTS: The success rate of treated patients was 37 (75.5 %) of all 49 included patients. The most frequent cause for the skin deficit was a tumor resection near the tip of the nose followed by skin deficits resulting after craniectomy. Interestingly, a higher number of expanders and a larger volume were significantly associated with a worse outcome. There was a trend of association between larger defect size and failure, too. CONCLUSIONS: The internal tissue expansion is a suitable technique for skin reconstruction in the head and face area. Compared to distant or free flaps, it often offers a better cosmetic outcome. In very large defects (>100 cm(2)) or when more than two expanders are needed, the failure rate increases. In these cases, other treatment options are recommended. CLINICAL RELEVANCE: The internal tissue expansion is a suitable technique for skin reconstruction in the head and face area.

Effects on general pain perception and dental pulp sensibility in probable sleep bruxism subjects by experimentally induced pain in a pilot study.

In this pilot study, the general pain perception and the dental pulp sensibility of probable sleep bruxism (SB) subjects were compared with that of non-SB subjects. The cold pressor test (CPT), electric pulp test (EPT), and thermal pulp test with CO2 snow were executed by one trained dentist (blind to SB diagnosis). A one-factorial multivariate analysis of variance (MANOVA) with SB diagnosis as independent variable and standardized measures regarding pain perception and evaluation was performed. One-hundred-and-five participants (53 SB and 52 non-SB subjects) were included. The one-factorial MANOVA revealed a significant difference between SB and non-SB subjects (p = 0.01) concerning pain perception variables. Post-hoc univariate analyses of variance (ANOVA) showed statistically significant lower general pain tolerance (p = 0.02), higher general subjective sensibility of the teeth (p < 0.01), and a statistical trend for higher subjective dental pain intensity (p = 0.07) in SB subjects. In most of the standardized variables, probable SB subjects seem to react and feel similar to non-SB subjects. However, as probable SB subjects subjectively perceive their teeth to be more sensitive and tend to rate their subjective dental pain intensity more intensely after CO2 testing, data might point to a somatosensory amplification.

Intraoral schwannoma: review of the literature and presentation of a rare case.

Schwannomas, also known as neurilemomas or neurilemmomas, are relatively uncommon, slow-growing benign tumors. Whereas, about one-third of all extracranial Schwannomas are found in the head and neck region, a few intraoral Schwannomas are reported in the literature. This article contributes to a review regarding the current literature and the report of a rare case. The literature searches were performed using the National Library of Medicine. Keywords used in the search were: schwannoma or neurilemmoma and intraoral. The literature search revealed 16,906 reports containing the word schwannoma; however, only 1,117 articles described this tumor entity in the "head and neck" region. The search item intraoral, in addition to schwannoma or neurilemmoma, were found in only 29 reports. In most cases, intraoral schwannomas are benign, slowly growing tumors. The treatment of choice is surgical excision. However, malignant schwannomas can also occur, and need a radical resection and a dissection of the regional lymph nodes.

Simultaneous PSI-Based Orthognathic and PEEK Bone Augmentation Surgery Leads to Improved Symmetric Facial Appearance in Craniofacial Malformations.

(1) The aim of the present study was to compare the outcome of facial symmetry after simultaneous digitally planned patient-specific implant (PSI-) based orthognathic surgery and polyether ether ketone (PEEK) bone augmentation in patients with craniofacial malformations. (2) To evaluate the outcome of the two different surgical approaches (conventional PSI-based orthognathic surgery versus simultaneous PSI-based orthognathic surgery with PEEK bone augmentation), a comparison of five different groups with a combination of the parameters (A) with vs. without laterognathia, (B) syndromic vs. non-syndromic, and (C) surgery with vs. without PEEK bone augmentation was conducted. The digital workflow comprised cone beam CT (CBCT) scans and virtual surgery planning for all patients in order to produce patient specific cutting guides and osteosynthesis plates. Additionally, deformed skulls were superimposed by a non-deformed skull and/or the healthy side was mirrored to produce PSI PEEK implants for augmentation. Retrospective analyses included posterior-anterior conventional radiographs as well as en face photographs taken before and nine months after surgery. (3) Simultaneous orthognathic surgery with PEEK bone augmentation significantly improves facial symmetry compared to conventional orthognathic surgery (6.5%P (3.2-9.8%P) (p = 0.001). (4) PSI-based orthognathic surgery led to improved horizontal bone alignment in all patients. Simultaneous PEEK bone augmentation enhanced facial symmetry even in patients with syndrome-related underdevelopment of both soft and hard tissues.

Influence of Xenogeneic and Alloplastic Carriers for Bone Augmentation on Human Unrestricted Somatic Stem Cells.

Alloplastic and xenogeneic bone grafting materials are frequently used for bone augmentation. The effect of these materials on precursor cells for bone augmentation is yet to be determined. The aim of this study was to ascertain, in vitro, how augmentation materials influence the growth rates and viability of human unrestricted somatic stem cells. The biocompatibility of two xenogeneic and one alloplastic bone graft was tested using human unrestricted somatic stem cells (USSCs). Proliferation, growth, survival and attachment of unrestricted somatic stem cells were monitored after 24 h, 48 h and 7 days. Furthermore, cell shape and morphology were evaluated by SEM. Scaffolds were assessed for their physical properties by Micro-CT imaging. USSCs showed distinct proliferation on the different carriers. Greatest proliferation was observed on the xenogeneic carriers along with improved viability of the cells. Pore sizes of the scaffolds varied significantly, with the xenogeneic materials providing greater pore sizes than the synthetic inorganic material. Unrestricted somatic stem cells in combination with a bovine collagenous bone block seem to be very compatible. A scaffold's surface morphology, pore size and bioactive characteristics influence the proliferation, attachment and viability of USSCs.

Therapies most frequently used for the management of bruxism by a sample of German dentists.

STATEMENT OF PROBLEM: At present, there is little information available on how practicing dentists manage bruxism patients with respect to conservative, reversible techniques as compared to irreversible techniques. PURPOSE: The purpose of this study was to determine the most commonly applied therapies used for the management of bruxism by German general dentists (GDs) and dental specialists. In addition, efforts were made to gather information on the knowledge and opinion of GDs and specialists regarding the role of occlusal interferences, in particular, on the development of sleep bruxism. MATERIAL AND METHODS: A 13-item questionnaire was developed and mailed to all active members of the statutory dental insurance providers of the German North Rhine (n=5500; 2006 roster) and the German Westphalia-Lippe area (n=4984; 2006 roster). Group differences were statistically analyzed using chi-square tests for the qualitative variables and Mann-Whitney U tests for the quantitative variables (α=.05). RESULTS: Occlusal splints were by far the most frequently prescribed therapy for the management of bruxism, followed by relaxation techniques, occlusal equilibration, physiotherapy, and prosthodontic reconstruction. The occlusal stabilization splint with canine protected articulation was the splint type most often prescribed, whereas respondents used unadjusted soft splints for approximately 8% of their bruxism patients. Comparison of the opinions of all responding practicing dentists with that of experts in regard to the statement that "sleep bruxism is caused by occlusal interferences" showed a significant difference between the 2 groups (P=.021). Eighty-five percent of the experts disagreed with this statement, and only 47.7% of the practicing dentists had the same opinion as the experts. CONCLUSIONS: Most practicing dentists seem to concur with current scientific recommendations, and express the opinion that the management of bruxism should predominantly be conservative and reversible; however, the findings of the present survey reveal diverse differences between GDs and dental specialists concerning the most frequently prescribed therapies. Moreover, the discrepancies detected in some areas, such as the use of irreversible techniques or the use of unadjusted soft splints, emphasize the need to more promptly transfer new knowledge in the field of bruxism from researchers to practicing dentists.

Navigated Recovery of Fractured Dental Injection Needles: Case Report and Suggestions for Management during Pandemic Crises.

Dislocation of a fractured hypodermic needle is a complication requiring immediate and adequate emergency treatment. In this case report, 3D navigation is evaluated for its use to recover a quickly moving fractured needle. The needle was recovered safely, but it could be demonstrated that navigational planning has to be conducted right before surgery and other navigational tools, such as ultrasound, should be considered as well. Furthermore, an approach is suggested for treatment during pandemic crises such as COVID-19.

A survey on German dentists regarding the management of craniomandibular disorders.

The purpose of the present investigation was to identify the most frequent therapies and, in particular, the prescription patterns for occlusal splints for the management of craniomandibular disorders (CMDs) used by German general dentists and specialists. Additionally, the knowledge and opinion of the practising dentists were examined. All active members of the statutory dental insurance providers of the German North Rhine (n = 5,500) and the Westphalia-Lippe area (n = 4,984) were surveyed with a questionnaire by mail. Results indicated that occlusal splints were the first-choice therapy followed by physiotherapy and occlusal equilibration. In the preceding year, both general dentists and specialists made 30 occlusal splints on average. With regard to high-quality evidence-based recommendations, some statistically significant discrepancies between general dentists and specialists were detected. On the basis of the present data, it seems useful to consider intensifying the topic of CMDs and orofacial pain in future undergraduate dental curricula and in postgraduate training.

Multiple recurrent follicular dendritic cell sarcoma: A case report.

Tumors of the follicular dendritic cells (FDC-Sarcoma) represent a rare entity with only about 200 cases reported worldwide. The majority (60%) of cases arise primarily in cervical, abdominal or axillar lymph nodes, but extra nodal origin from secondary lymphatic tissue like the tonsils, Waldeyer's ring or MALT is also common (40%). The current report presents a characteristic course of a cervical FDC-Sarcoma, with its challenges in establishing the initial diagnosis and the struggle for therapeutic options. The FDC-Sarcoma presented recurrently for four times. Three different university hospitals in Germany were involved in the patients' treatment. Due to the patients' refusal, no adjuvant therapy was applied. In the end, a neck dissection was performed. The patient was closely followed up and has been recurrence-free for 10 years. This case suggests operative resection in combination with a neck dissection as a curative therapy for FDC-Sarcoma of the head and neck.

Compatibility of embryonic stem cells with biomaterials.

Periodontal bone defects and atrophy of the jaws in an aging population are of special concern. Tissue engineering using embryonic stem cells (ESCs) and biomaterials may offer new therapeutic options. The purpose of this study is to evaluate the compatibility of ESCs with biomaterials and the influence of biomaterials on the osteogenic gene expression profile.Therefore, ESCs are cultured with various biomaterials. The cytocompatibility of murine ESCs is measured regarding the proliferation of the cells on the materials by CyQUANT assay, the morphology by scanning electron microscopy, and the influence on the gene expression by real time PCR.The results show that insoluble collagenous bone matrix, followed by beta-tricalciumphosphate, is most suitable for bone tissue engineering regarding cell proliferation, and phenotype. The gene expression analysis indicates that biomaterials do influence the gene expression of ESCs.Our results provide new insight into the cytocompatibility of ESCs on different scaffolds.

Evaluation of the oral health-related quality of life in patients with odontogenic fascial space abscesses and underlying conditions - a prospective questionnaire-based study.

BACKGROUND: Oral Health-Related Quality of Life (OHRQoL) is an important aspect of quality of life. Acute illnesses, as well as chronic diseases, can have a strong, persisting impact on an individual's quality of life. This study evaluates OHRQoL of patients with odontogenic fascial space abscesses, the underlying conditions, and its consequences for clinical routines. METHODS: The research group consisted of patients presenting themselves to the emergency room or elective clinic of the Department for Cranio-Maxillofacial and Plastic Surgery (n = 94). The validated German version of the Oral Health Impact Profile (OHIP-G) and additional questions (including habits and routines in oral hygiene) with an anamnestic recall period of 1 month was used to evaluate OHRQoL shortly after emergency treatment (baseline) and again after 3-6 months' follow-up. Ninety-four patients completed the questionnaire at baseline, 54 completed both questionnaires. Additionally, OHIP-G scores were compared to those of the non-impacted general German population. RESULTS: Results showed a significant difference in OHIP-G scores from baseline to follow-up (p = 0.001). Overall a mean of 55.24 (±37.02) points was scored at baseline and a mean of 37.02 (±35.79) points was scored at follow-up. Patients scored higher than participants of a representative study of the general German population. CONCLUSION: Overall results suggest an increase in OHRQoL 3-6 months after acute treatment. Nevertheless, OHRQoL of patients suffering from odontogenic fascial space abscesses seems to remain generally lower than the OHRQoL of the general German population. TRIAL REGISTRATION: Trial registration: Central Study Register of the University Hospital Duesseldorf, Registration-ID: 2016085405 . Registered 24 August 2016.

Release kinetics of the model protein FITC-BSA from different polymer-coated bovine bone substitutes.

BACKGROUND: Controlled release of proteins bound to conventional bone substitutes is still insufficient. Therefore, this study evaluates in-vitro release kinetics of the model protein FITC-BSA (fluorescein conjugated bovine serum albumine) from insoluble bovine collagenous bone matrices (ICBM) with different polymer coatings. Analyzes aim at comparing FITC-BSA release from uncoated versus coated ICBM over time to find bone substitute coatings with consistent release profiles. METHODS: Release kinetics of FITC-BSA from uncoated as well as coated ICBM with five different polymers (RESOMER R 203 H, RG 503 H, RG 504 H, RG 505, L 206 S) were measured over a period of 11 days (d). Measurements were conducted after 6 h (h), 12 h, 24 h, 3 d, 5 d, 7 d, 9 d and 11 d with six samples for each coated ICBM. Two groups were formed (1) with and (2) without medium change at times of measurement. For each group ANOVA with post-hoc Bonferroni testing was used. Scanning electron microscopy assessed morphologic differences between ICBM coating. RESULTS: In group 1 approx. 70% of FITC-BSA release from uncoated ICBM occurred after 6 h compared to approx. 50% in group 2. Only polymers with medium inherent viscosity, i.e. RESOMER RG 503 H, constantly showed significantly more FITC-BSA release throughout 11 d than uncoated ICBM (p = 0.007). The same was found for group 2 (p = 0.005). No significant differences between PLA and PLGA polymers were found. Scanning electron microscopy results indicate a weak adhesion of polymer coatings to ICBM explaining its rather weak retentive effect on overall FITC-BSA release. CONCLUSIONS: Medium molecular size polymers reduce the overall released FITC-BSA from ICBM over time. In clinical practice these polymers may prove ideal for bone substitute materials.

Evaluation of Biocompatibility of Different Membrane Surfaces Using Unrestricted Somatic Stem Cells.

BACKGROUND/AIM: Results of Guided Bone Regeneration (GBR) primarily depend on the membrane used. The aim of this study was to compare biocompatibility of different absorbable and non-absorbable membranes by using unrestricted somatic stem cells (USSCs) as an indicator for biocompatibility. MATERIALS AND METHODS: Five absorbable membranes (Bio-Gide®, RESODONT®, GENTA-FOIL resorb®, BioMend® and BioMend® Extend™) and one non-absorbable alternative (GORE-TEX®) were colonized with USSCs. After 24 h, 3 days and 7 days, cell proliferation, cell viability, and cytotoxicity were assessed. Moreover, cell morphology was evaluated by electron microscopy. RESULTS: Significantly higher cell proliferation and cell viability rates were observed in Bio-Gide® and RESODONT® membranes. Cell toxicity was highest on GENTA-FOIL resorb® membranes. The electron microscopical assessment showed a better cell attachment on porous surfaced membranes. CONCLUSION: This study shows that USSCs can be used for assessments of biocompatibility, and that absorbable membranes with collagenous composition and porous structure tend to positively impact biocompatibility and enhance cell proliferation.

Pain perception and functional/occlusal parameters in sleep bruxism subjects following a therapeutic intervention.

BACKGROUND: This study was conducted to assess the individual pain perception in sleep bruxism (SB) subjects. Moreover, the effects of a cognitive behavioural therapy (CBT) compared to an occlusal appliance (OA) on pain perception and a possible continuative impact on several functional parameters were investigated. METHODS: A total of 57 SB subjects participated in this investigation. The diagnosis of SB was based on the clinical criteria of the American Academy of Sleep Medicine (AASM). Twenty-eight SB subjects were randomly allocated to the CBT group and 29 to the OA group. The therapeutic intervention took place over a period of 12 weeks, whereby both groups were examined at baseline, immediately after termination of the intervention, and at a 6-month follow-up for pain perception and functional parameters. At each of the three measurement periods, participants completed the pain perception scale and ten functional/occlusal parameters were recorded. RESULTS: Of the 12 parameters recorded, statistically significant main effects were found for the affective pain perception (p < 0.05) and for the three functional variables. Interestingly, the values obtained for the affective pain perception were considerably below that of a reference group. Apart from the determined statistically significant results, the values recorded for all functional/occlusal variables as well as those obtained for the sensory pain perception were clearly located within normative ranges. CONCLUSIONS: Within the limitations of this study, it might be concluded that the significantly reduced affective pain perception in SB subjects is the expression of an adaptation mechanism.

Extensive Craniocervical Abscess after Transoral Ganglionic Local Opioid Analgesia at the Superior Cervical Ganglion for Atypical Trigeminal Neuralgia: Report of a Severely Complicated Case.

Ganglionic local opioid analgesia (GLOA) describes the application of low-dose opioids close to sympathetic as, for example, to the superior cervical ganglion. GLOA can be effective in different pain syndromes affecting the head and face region and has been considered to be a safe technique with few complications reported so far. We present the case of a patient who received a single, transoral GLOA for a refractory trigeminal neuralgia. The patient subsequently developed an extensive epidural abscess at the craniocervical junction, requiring ultimately transoral odontoid resection and dorsal stabilisation. This severe complication challenges the role of transoral infiltration therapies in analgetic medicine.

Pathogenesis of medication-related osteonecrosis of the jaw: a comparative study of in vivo and in vitro trials.

Objective This study was performed to determine whether the results of prevailing in vivo and in vitro studies offer a reliable model for investigation of medication-related osteonecrosis of the jaw (MRONJ). Methods Embase, Medline, and the Cochrane Library were searched for articles published from September 2003 to June 2017 involving experimental approaches to the pathogenesis of MRONJ. In vivo and in vitro trials were analyzed with respect to the scientific question, study design, methodology, and results. Results Of 139 studies, 87, 46, and 6 conducted in vivo, in vitro, and both in vivo and in vitro experiments, respectively. Rats, mice, dogs, minipigs, sheep, and rabbits were the preferred animal models used. Osteoblasts, osteoclasts, fibroblasts, keratinocytes, macrophages, and human umbilical vein endothelial cells were the preferred cell types. Zoledronate, alendronate, ibandronate, and risedronate were the most frequent bisphosphonates used. MRONJ was most reliably induced in minipigs because of the close relationship with human bone physiology. In vitro studies showed that reduced viability, growth, and migration of cells in the bone and soft tissues were causative for MRONJ. Other than exposed jawbone after tooth extraction, no reliable cofactors were found. Conclusion The minipig is the most suitable animal model for MRONJ.

Vertical bone regeneration using rhBMP-2 and VEGF.

BACKGROUND: Sufficient vertical and lateral bone supply and a competent osteogenic healing process are prerequisities for the successful osseointegration of dental implants in the alveolar bone. Several techniques including autologous bone grafts and guided bone regeneration are applied to improve quality and quantity of bone at the implantation site. Depending on the amount of lacking bone one- or two-stage procedures are required. Vertical bone augmentation has proven to be a challenge particularly in terms of bone volume stability. This study focuses on the three dimensional vertical bone generation in a one stage procedure in vivo. Therefore, a collagenous disc-shaped scaffold (ICBM = Insoluble Collagenous Bone Matrix) containing rhBMP-2 (Bone Morphogenetic Protein-2) and/or VEGF (Vascular Endothelial Growth Factor) was applied around the coronal part of a dental implant during insertion. RhBMP-2 and VEGF released directly at the implantation site were assumed to induce the generation of new vertical bone around the implant. METHODS: One hundred eight titanium implants were inserted into the mandible and the tibia of 12 mini pigs. Four experimental groups were formed: Control group, ICBM, ICBM + BMP-2, and ICBM + BMP-2 + VEGF. After 1, 4 and 12 weeks the animals were sacrificed and bone generation was investigated histologically and histomorphometrically. RESULTS: After 12 weeks the combination of ICBM + rhBMP2 + VEGF showed significantly more bone volume density (BVD%), a higher vertical bone gain (VBG) and more vertical bone gain around the implant (PVBG) in comparison to the control group. CONCLUSION: By using collagenous disc-shaped matrices in combination with rhBMP-2 and VEGF vertical bone can be generated in a one stage procedure without donor site morbidity. The results of the presenting study suggest that the combination of rhBMP-2 and VEGF applied locally by using a collagenous carrier improves vertical bone generation in vivo. Further research is needed to establish whether this technique is applicable in clinical routines.

Cell-based bone reconstruction therapies--cell sources.

Over the last few decades, reconstructive surgery has shifted from a resection-oriented approach toward strategies focusing on repair and regeneration of tissues. As the main aim of maxillofacial reconstruction has been the restoration of bone form and function, surgeons used artificial tissue substitutes in the early decades of bone reconstruction. These artificial materials significantly improved the ability of surgeons to restore the form and, to some extent, the function of defective bones. Despite the fact that every artificial material has specific disadvantages, the use of biomaterials is a common treatment option in clinical practice even today. Due to the more detailed understanding that exists concerning transplantation of cells and tissues, autogenous grafts are the second mainstay in clinical practice. However, the main disadvantage of using autogenous grafts is donor site morbidity and donor shortage. Research is currently in progress into the use of cell-based approaches in reconstructive surgery, since cells are the driving elements for all repair and regeneration processes. Various cell populations have been reported on in the relevant literature. These cells can be classified according to differentiation capacity and the tissue from which they originated. In this review, unrestricted cells, multipotential progenitor cells, determined cells, and genetically modified cells are described systematically, and their advantages as well as limitations are discussed. (More than 50 references.)