Occlusal dysesthesia-A clinical guideline.

BACKGROUND: The diagnosis and management of patients suffering from occlusal dysesthesia (OD) remain a major challenge for dental practitioners and affected patients. OBJECTIVES: To present the results of a literature-based expert consensus intended to promote better understanding of OD and to facilitate the identification and management of affected patients. METHODS: In 2018, electronic literature searches were carried out in PubMed, Cochrane Library and Google Scholar as well as in the archives of relevant journals not listed in these databases. This approach was complemented by a careful assessment of the reference lists of the identified relevant papers. The articles were weighted by evidence level, followed by an evaluation of their contents and a discussion. The result represents an expert consensus. RESULTS: Based on the contents of the 77 articles identified in the search, the current knowledge about clinical characteristics, epidemiology, aetiology, diagnostic process, differential diagnosis and management of OD is summarised. CONCLUSIONS: Occlusal dysesthesia exists independently of the occlusion. Instead, it is the result of maladaptive signal processing. The focus should be on patient education, counselling, defocusing, cognitive behavioural therapy, supportive drug therapy and certain non-specific measures. Irreversible, specifically an exclusively dental treatment approach must be avoided.

Primary Stability of Cylindrical and Conical Dental Implants in Relation to Insertion Torque-A Comparative Ex Vivo Evaluation.

INTRODUCTION: The aim of this ex vivo study was to investigate the influence of different insertion torques on primary stability of a conical and a cylindrical implant system. MATERIALS AND METHODS: Thirty-two dental implants (Astra Tech OsseoSpeed 5.0 S × 11 mm cylindrical [n = 16] and 5.0 × 11 mm conical [n = 16]) were inserted with 20, 30, 40, and 45 N·cm into fresh porcine bone of mixed trabecular-cortical quality. Before insertion, bone quality was assessed via cone beam tomography. After insertion, resonance frequency analysis was reported using the implant stability quotient (ISQ). Implant insertion depths were evaluated, and the implants were pushed out of the bone by force (measured in N). All experiments were done with n = 4 per group. RESULTS: The highest ISQ (mean 78.25 ± 2.9) and pushout values (mean 675 N ± 5.8) were measured for the cylindrical implant after insertion using 30 N·cm. The conical implant showed the highest primary stability by means of ISQ (mean 76.25 ± 2.2) and pushout force (mean 502.5 N ± 9.6) after an insertion torque of 40 N·cm. If more insertion force was used, primary stability was reduced in all cases. CONCLUSION: The data indicate that different forms of an implant system need different insertion torques to obtain an optimal primary stability. These results have to be verified clinically.

Controversial Aspects of Diagnostics and Therapy of Idiopathic Condylar Resorption: An Analysis of Evidence- and Consensus-Based Recommendations Based on an Interdisciplinary Guideline Project.

Idiopathic condylar resorption (ICR), though a rare event, is associated with severe detrimental sequelae for the patient. To date, the etiology remains unknown, and treatment strategies are highly controversial. Therefore, the aim of this study is to present an analysis of the consensus- and evidence-based approach to ICR by a German interdisciplinary guideline project of the AWMF (Association of the Scientific Medical Societies in Germany). Following a systematic literature search, including 56 (out of an initial 97) publications, with a predominantly low level of evidence (LoE), two independent working groups (oral and maxillofacial surgery and interdisciplinary, respectively) voted on a draft comprising 25 recommendations in a standardized anonymized and blinded Delphi procedure. While the results of the votes were relatively homogeneous, the interdisciplinary phase required a significantly higher number of rounds (p < 0.001). Most of the controversial recommendations were related to initial imaging (with consensus on CT/CBCT as the current diagnostic standard for imaging), pharmacotherapy (no recommendation due to lack of evidence), discopexy (no recommendation possible due to low LoE) and timing of orthognathic surgery (with consensus on two-staged procedures after invasive TMJ surgery, except for single-stage procedures if combined with total joint reconstruction). Overall, the Delphi procedure resulted in an interdisciplinary guideline offering the best possible evidence- and consensus-based expertise to date in the diagnosis and treatment of ICR.

Comparative Sample Preparation Using Focused Ion Beam and Ultramicrotomy of Human Dental Enamel and Dentine for Multimicroscopic Imaging at Micro- and Nanoscale.

(1) Background: The aim of this study was to systematically compare TEM sections of mineralized human enamel and dentine prepared by focused ion beam (in situ lift-out) technique and ultramicrotomy through a combination of microscopic examination methods (scanning electron microscopy and transmission electron microscopy). In contrast with published studies, we compared the TEM preparation methods using the same specimen blocks as those for the ultramicrotomy and FIB technique. (2) Methods: A further evaluation of TEM sample preparation was obtained by confocal laser scanning microscopy and atomic force microscopy. In addition, ultramicrotome- and focused ion beam-induced artefacts are illustrated. (3) Results: The FIB technique exposed a major difference between non-decalcified enamel and dentine concerning the ultrastructural morphology compared to ultramicrotome-prepared sections. We found that ultramicrotomy was useful for cutting mineralized dentine, with the possibility of mechanical artefacts, but offers limited options for the preparation of mineralized enamel. FIB preparation produced high-quality TEM sections, showing the anisotropic ultrastructural morphology in detail, with minor structural artefacts. Our results show that the solution of artificial saliva and glutardialdehyde (2.5% by volume) is a very suitable fixative for human mineralized tissue. (4) Conclusions: The protocol that we developed has strong potential for the preparation of mineralized biomaterials for TEM imaging and analysis.

Controversial Aspects of Diagnostics and Therapy of Arthritis of the Temporomandibular Joint in Rheumatoid and Juvenile Idiopathic Arthritis-An Analysis of Evidence- and Consensus-Based Recommendations Based on an Interdisciplinary Guideline Project.

Introduction: Due to potentially severe sequelae (impaired growth, condylar resorption, and ankylosis) early diagnosis of chronic rheumatic arthritis of the temporomandibular joint (TMJ) and timely onset of therapy are essential. Aim: Owing to very limited evidence the aim of the study was to identify and discuss controversial topics in the guideline development to promote further focused research. Methods: Through a systematic literature search, 394 out of 3771 publications were included in a German interdisciplinary guideline draft. Two workgroups (1: oral and maxillofacial surgery, 2: interdisciplinary) voted on 77 recommendations/statements, in 2 independent anonymized and blinded consensus phases (Delphi process). Results: The voting results were relatively homogenous, except for a greater proportion of abstentions amongst the interdisciplinary group (p < 0.001). Eighty-four percent of recommendations/statements were approved in the first round, 89% with strong consensus. Fourteen recommendations/statements (18.2%) required a prolonged consensus phase and further discussion. Discussion: Contrast-enhanced MRI was confirmed as the method of choice for the diagnosis of TMJ arthritis. Intraarticular corticosteroid injection is to be limited to therapy-refractory cases and single injection only. In adults, alloplastic joint replacement is preferable to autologous replacement. In children/adolescents, autologous reconstruction may be performed lacking viable alternatives. Alloplastic options are currently still considered experimental.

Prospective clinical implementation of optional implant treatment into pregraduate dental education-mini implants for retention and support of mandibular overdentures.

BACKGROUND: The primary aim of the study was to evaluate mini implant (MDI) survival, prosthodontic maintenance, and patient-reported outcome measures after conducting an optional pregraduate academic course on patients with mandibular edentulism including fabrication of overdentures and MDI planning and placement as well as chair-side incorporation of the respective restauration. In a prospective clinical study, 20 patients received 80 MDIs that were restored with mandibular overdentures. All treatment steps including placement of 40 MDIs were conducted by undergraduate students under strict guidance of a consultant. Next to students' perceptions after participation, survival of MDIs, and prosthodontic maintenance, patients' perceptions as well as peri-implant parameters were assessed after 4 weeks and 3 and 12 months. RESULTS: Three MDIs fractured (two during insertion and one after 3 months; total survival 96.25%). Two overdentures fractured and a total of 23 cases of minor prosthodontic maintenance were required. Over time, patients' satisfaction significantly increased. Besides, questionnaires showed a high rate of students' positive perception and high self-confidence to include MDI therapy into own practice. CONCLUSIONS: The results are in accordance to those reported by postgraduate dentists. In accordance, therapy with MDI-retained mandibular overdentures seems to be feasible and successful at pregraduate level if the students receive guidance.

Marginal and Internal Precision of Zirconia Four-Unit Fixed Partial Denture Frameworks Produced Using Four Milling Systems.

BACKGROUND: CAD/CAM systems enable the production of fixed partial dentures with small and reproducible internal and marginal gaps. PURPOSE: The purpose of this study was to evaluate the reproducibility of the marginal and internal adaptations of four-unit fixed partial denture frameworks produced using four CAD/CAM systems. MATERIALS AND METHODS: Prepared dies of a master model that simulated the loss of the first left molar were measured. Fifteen frameworks were manufactured using four CAD/CAM systems (A-D). The internal fit was determined by the replica technique, and the marginal gap was determined by microscopy. ANOVA was carried out to detect significant differences, and the Bonferroni adjustment was performed. The global level of significance was set at 5%. RESULTS: The mean gap size ranged from 84 to 132 µm (SD 43-71 µm). The CAD/CAM systems showed significant variance (p < 0.001), and system A (VHF) showed the smallest gaps. The smallest gaps for each system were in the molar part and in the marginal region of the frameworks (p < 0.001). CONCLUSIONS: The CAD/CAM systems showed significantly different gap sizes, particularly between premolars and molars and among the marginal, axial and occlusal regions. All of the systems are suitable for clinical application.

Does the Modification of the Apical Geometry of a Dental Implant Affect Its Primary Stability? A Comparative Ex Vivo Study.

(1) Background: Primary stability-one fundamental criterion for the success of dental implants-is influenced by implant geometry even if the effect of apical shape modifications on implant primary stability has not yet been examined. Therefore, the aim of the ex vivo study was to compare primary stability of implants differing in apically located screw threads (J-line) or a flat tip (K-line) only. (2) Methods: 28 implants of each group of the same diameter (4.3 mm) were randomly inserted into porcine bone blocks. The first group (9, 11 and 13 mm) was inserted into "hard", the second (11 mm) into "soft" bone, here using a normal and an undersized drilling protocol. Insertion torque (Ncm), Periotest® value, resonance frequency (implant stability coefficient, ISQ) and push-out force (N) were measured. (3) Results: In "hard" bone, primary stability increased with increasing length in both groups but it was significantly higher in J-line (p < 0.03). An undersized preparation of the implant bed in "soft" bone resulted in a significant increase in primary stability in both groups. Here, J-line also showed a significantly increased primary stability when compared to equally prepared K-line (insertion torque: 37 Ncm vs. 26 Ncm; Periotest®: -6.5 vs. -4.3; push-out force: 365 N vs. 329 N; p < 0.05 each). (4) Conclusions: Primary stability is significantly higher with increasing implant length and apically located screw threads as well as with undersized drilling protocols. When preparing the implant site and subsequently selecting the implant system, modifying factors such as implant geometry (also at the tip) should be taken into account.

A collagen membrane influences bone turnover marker in vivo after bone augmentation with xenogenic bone.

BACKGROUND: The aim was to compare early biochemical and histological osseous healing of chronic mandibular defects regenerated with bovine bone substitute with and without collagen membrane in vivo. METHODS: Eight weeks after formation of a lateral full-thickness perforating bone defect in the mandible of 40 rabbits, bovine bone substitute with ("+";n = 20) and without ("-";n = 20) collagen membrane was applied. Blood and bone was collected 24, 72 h, 7, 14 and 21 days after surgery. Total acid phosphatase, bone acid phosphatase, total alkaline phosphatase and bone alkaline phosphatase activities were compared between groups. Formation of new bone was quantified histologically for all time points. RESULTS: Twenty-four hours after surgery, bone alkaline phosphatase was significantly elevated in "+" group when compared to "-" (p=0.012). After 72 hours, all bone turnover markers except for total acid phosphatase (p=0.078) where significantly elevated in "+" (all p < 0.05). Fourteen days after surgery, the significant highest values for all bone turnover markers were detected in "-" (all p < 0.05). A significant difference in favor of group "-" could also be detected after 3 weeks in terms of both acid phosphatases (p < 0.05). In histology, no significant differences could be detected. CONCLUSION: Bone regeneration with bovine bone substitute material and collagen membrane shows a significantly earlier bone remodeling activity but does not seem to influence formation of new bone in histological samples.

[The influence of macro- and microstructure on the surface wettability and retention properties of endodontic posts in vitro]. / Der Einfluss der Makro- und Mikrostruktur auf die Benetzungs- und Retentionseigenschaften von Wurzelkanalstiften in vitro.

Aesthetical and biomechanical requirements on fiber-reinforced endodontic posts play an important role in clinical application. Leading to a long-term clinical success, post systems must ensure an adequate force transmission and optimal retention behavior into the root channel. The aim of this study was to determine the microstructure and morphology of commonly used fiber reinforced endodontic posts in vitro. Post-specific fiber diameter, fiber arrangement over the cross-sections and length, and fiber-matrix ratio could be associated with mechanical properties, such as three-point bending strength and structure modulus. Furthermore, our investigation focused on the quantification of the wettability of the post surface. By using a modified contact-angle measurement, the meniscus on the post surface was characterized. In additional investigations, posts were inserted in artificial root channels and the extraction force was measured. The results show a strong correlation between the extraction force and the wettability of the post surface.

Retrospective study on the evaluation of the TMJ by MRI using a newly developed standardized evaluation form.

The objectives of this retrospective study were to systematically assess the temporomandibular joint (TMJ) using a newly developed standardized evaluation form with 16 parameters based on MRI diagnostics and to verify the reliability of the MRI diagnoses. One hundred fifty-four (154) TMJs of 77 patients with arthrogenic complaints were evaluated using MRI on two planes (parasagittal, paracoronal), in both closed-mouth and open-mouth positions. The sequences used were intermediary FLASH and spin echo sequences using T1 or T2 weighting with fat suppression. Examination of the reliability of the MRI evaluations of three independent observers evaluating 60 randomly selected TMJ from among the overall sample using the new evaluation form yielded an average Pearson contingency coefficient of between 0.64 and 0.70 with regard to the 16 parameters studied. In the evaluation of the 77 left (L) and 77 right (R) joints, the biplanar morphology of the disk was the most frequent with 24.7% (L) and 32.5% (R). In paracoronal projection, medial displacement of the disk was seen in 7.9% (L, R) of the cases and lateral displacement in 6.4% (L) and 3.2% (R). The use of the new evaluation form, in combination with MRI of the TMJ, demonstrated a substantial reliability of the diagnoses. In TMD patients, the biconcave disk shape cannot be considered the sole normal, standard situation. The presence of lateral and medial disk displacement should be given more diagnostic consideration.

In vitro aging behavior of dental composites considering the influence of filler content, storage media and incubation time.

OBJECTIVE: Over time dental composites age due to mechanical impacts such as chewing and chemical impacts such as saliva enzymes and food ingredients. For this research, the focus was placed on chemical degradation. The objective of this study was to simulate hydrolysis by using different food simulating liquids and to assess their impact on the mechanical parameter Vickers microhardness (MHV) and the physicochemical parameter contact angle (CA). METHODS: Specimen of three composites (d = 6 mm, h = 2 mm; n = 435) classified with respect to their filler content (wt%), namely low-filled, medium-filled and highly-filled, were stored for 0, 14, 30, 90 and 180 days in artificial saliva (pH 7), citric acid (pH 3; pH 5), lactic acid (pH 3; pH 5) and ethanol (40%vol; 60%vol) and assessed regarding to MHV and CA. Statistics: Kruskal-Wallis test, stepwise linear regression, bivariate Spearman Rank Correlation (p < 0.05). RESULTS: While stored in artificial saliva, acid and ethanol the CA decreased especially for the low- and medium-filled composites. It was shown that rising the filler content caused less surface changes in the CA. Storage in ethanol led to a significant decrease of MHV of all composites. Regression analysis showed that the effect of in vitro aging on MHV was mainly influenced by the composite material and therefore by filler content (R2 = 0.67; p < 0.05). In contrast, the CA is more influenced by incubation time and filler content (R2 = 0.2; p < 0.05) leading to a higher risk of plaque accumulation over time. Significance: In vitro aging showed significant changes on the mechanical and physicochemical properties of dental composites which may shorten their long-term functionality. In conclusion, it can be stated, that the type of composite material, especially rising filler content seems to improve the materials' resistance against the processes of chemical degradation.

The Treatment of Temporomandibular Joint Dislocation.

BACKGROUND: The estimated incidence of temporomandibular joint dislocation in Germany is at least 25/100 000 per year. A correct diagnosis and the initiation of appropriate treatment without delay are essential if permanent damage to the joint is to be avoided. METHODS: This review is based on pertinent publications retrieved by a systematic search in the PubMed, Cochrane, Embase, and ZB Med databases. RESULTS: The initial search yielded 24 650 hits; duplicates were removed and 136 studies were chosen for further analysis. The diagnosis of temporomandibular joint dislocation is generally made clinically from the finding of a lower jaw that is fixed in the open position. Acute dislocations are manually repositioned at once. The most common method is Hippocratic repositioning, in which the physician's thumb is placed laterally next to the teeth and the other fingers are placed on the lower surface of the lower jaw. The physician then exerts pressure, first caudally, then dorsally. Repositioning is carried out in two steps. For dislocations that have been present for a longer time, manual repositioning may be ineffective and surgery may be needed. Recurrent dislocation can be treated in a minimally invasive way with botulinum toxin injections or autologous blood therapy. Surgery may be needed if these methods are ineffective. CONCLUSION: There have been no more than a few randomized, controlled trials of treatments for temporomandibular joint dislocation, in particular concerning minimally invasive and open surgical treatments, and therefore only limited evidence-based conclusions can be drawn. Nonetheless, the diagnostic and therapeutic standards that have been established in recent years have gained wide international acceptance.

Correlation of ultrasound microscopy and Vickers hardness measurements of human dentin and enamel - A pilot study.

OBJECTIVE: To investigate if Vickers microhardness of dentin and enamel correlated with acoustic velocity c(l) or acoustic reflection from the sample's top (amplitude). METHODS: Eight transversal sections of a sound human tooth were investigated with scanning acoustic microscopy (SAM) and Vickers microhardness measurements. Longitudinal acoustic velocity c(l), amplitude and microhardness MHV were evaluated and for each c(l) test point corresponding amplitude and MHV were linearly interpolated and graphically analyzed. Spearman rank order correlation (rS) was calculated (p<0.05). RESULTS: c(l) was predominantly 6100-7000ms-1 in enamel and 3800-4600ms-1 in dentin and correlated significantly with MHV with 27-420 in enamel and 20-90 in dentin (rs=0,57). Amplitudes significantly correlated with MHV, too, but even better (rs=0,77). SIGNIFICANCE: Acoustic velocity and amplitudes were appropriate to detect microhardness differences of dentin and enamel and certain value ranges of both could be assigned to certain MHV ranges. Further research is needed to differentiate more precisely between the different hard tooth tissues.

Long-term bond between dual-polymerizing cementing agents and human hard dental tissue.

OBJECTIVES: To examine the long-term adhesion of seven dual-polymerizing cementing agents to human dentin in vitro. METHODS: Two hundred and eighty extracted non-carious human molars were ground flat to expose dentin surfaces. The bond strengths of cementing agents with their respective bonding systems were examined: one compomer cement (PermaCem), five resin cements (RelyX ARC, Panavia F, Variolink II, Nexus 2, Calibra) and one self-adhesive universal resin cement (RelyX Unicem). One subgroup (n=10) was tested after 150 days of storage in water at 37 degrees C (time t(1)), the other subgroup (n=10) was tested after 150 days of storage plus 37,500 thermal cycles (time t(2)). All specimens were stressed in shear at a constant crosshead speed of 0.5mm/min until failure. Statistical analysis was performed by ANOVA, taking effect interactions into account. The Tukey method was used for multiple paired comparisons (alpha=0.05). RESULTS: The three-way ANOVA (cementing agents, polymerization methods, times of measurements) showed Variolink II to have the highest strength at 9.9+/-4.5MPa. Values were slightly higher at t(1) (5.9+/-4.7MPa) than at t(2) (4.9+/-4.2MPa) (p=0.0044). Polymerization with light activation (6.5+/-5.1MPa) yielded higher strengths than polymerization without (4.3+/-3.3MPa) (p<0.0001). Separate two-way ANOVAs for t(1) and t(2) showed that the two main effects (cementing agent, polymerization method) and their interactions differed significantly. SIGNIFICANCE: Cementing agents/adhesive systems and the polymerization method influence the long-term bond to hard dental tissues.

Utilizing Moist or Dry Swabs for the Sampling of Nasal MRSA Carriers? An In Vivo and In Vitro Study.

This study investigates the quantitative bacterial recovery of Methicillin-resistant Staphylococcus aureus (MRSA) in nasal screenings by utilizing dry or moistened swabs within an in vivo and an in vitro experimental setting. 135 nasal MRSA carriers were each swabbed in one nostril with a dry and in the other one with a moistened rayon swab. Quantitative bacterial recovery was measured by standard viable count techniques. Furthermore, an anatomically correct artificial nose model was inoculated with a numerically defined suspension of MRSA and swabbed with dry and moistened rayon, polyurethane-foam and nylon-flocked swabs to test these different settings and swab-materials under identical laboratory conditions. In vivo, quantities of MRSA per nostril in carriers varied between <101 and >107 colony forming units, with a median of 2.15x104 CFU. However, no statistically significant differences could be detected for the recovery of MRSA quantities when swabbing nasal carriers with moist or dry rayon swabs. In vitro testing confirmed the in vivo data for swabs with rayon, polyurethane and nylon-flocked tips, since pre-moistening of swabs did not significantly affect the quantities of retrieved bacteria. Therefore, pre-moistening of swabs prior to nasal MRSA sampling provides no advantage in terms of recovering greater bacterial quantities and therefore can be omitted. In addition, this situation can be mimicked in an in vitro model, thereby providing a useful basis for future in vitro testings of new swab types or target organisms for screening approaches.

The value of MRI in patients with temporomandibular joint dysfunction: Correlation of MRI and clinical findings.

AIM: To estimate the correlation between the MRI findings and clinical outcomes in patients with temporomandibular joint dysfunction (TMD). METHODS AND MATERIALS: We included 546 female and 248 male patients who were clinically diagnosed with TMD (mean age 38.7 years) and examined by MRI (T1 and T2 weighted images, parasagittal and paracoronal slices). A questionnaire, radiological, and clinical findings were analysed for statistically significant correlations. The analysed parameters included gender, age, disk position, joint degeneration, arthralgia, mouth opening, condyle position and clinical progress. RESULTS: Of all TMJ's 62% showed physiological disc position, 35% anterior and 3% posterior disc position. Modification of therapy occurred in 20% and alteration of diagnosis was found in 32% of all cases. Anterior disc displacement with reduction showed a specificity of 88% and a sensitivity of 78%, whereas anterior disc displacement without reduction showed a specificity of 84% and a sensitivity of 73%. A significant correlation between disc length, condyle morphology and disc displacement was found. With the increase of intra-articular liquid as seen on MRI the level of arthralgia significantly rose as opposed to mouth opening. CONCLUSION: Specificity and sensitivity, for anterior disc displacement and osseous changes in TMJ were highly acceptable. Results had confirmed the diagnostic capability of MRI in diagnostic imaging of TMJ. Additionally MRI should be used primarily in severe, therapy-resistant cases and for surgical planning purposes.

Nasal screening for MRSA: different swabs--different results!

OBJECTIVES: Swab-based nasal screening is commonly used to identify asymptomatic carriage of Staphylococcus aureus in patients. Bacterial detection depends on the uptake and release capacities of the swabs and on the swabbing technique itself. This study investigates the performance of different swab-types in nasal MRSA-screening by utilizing a unique artificial nose model to provide realistic and standardized screening conditions. METHODS: An anatomically correct artificial nose model was inoculated with a numerically defined mixture of MRSA and Staphylococcus epidermidis bacteria at quantities of 4×10(2) and 8×10(2) colony forming units (CFU), respectively. Five swab-types were tested following a strict protocol. Bacterial recovery was measured for direct plating and after elution into Amies medium by standard viable count techniques. RESULTS: Mean recovered bacteria quantities varied between 209 and 0 CFU for MRSA, and 365 and 0 CFU for S. epidermidis, resulting swab-type-dependent MRSA-screening-sensitivities ranged between 0 and 100%. Swabs with nylon flocked tips or cellular foam tips performed significantly better compared to conventional rayon swabs referring to the recovered bacterial yield (p<0.001). Best results were obtained by using a flocked swab in combination with Amies preservation medium. Within the range of the utilized bacterial concentrations, recovery ratios for the particular swab-types were independent of the bacterial species. CONCLUSIONS: This study combines a realistic model of a human nose with standardized laboratory conditions to analyze swab-performance in MRSA-screening situations. Therefore, influences by inter-individual anatomical differences as well as diverse colonization densities in patients could be excluded. Recovery rates vary significantly between different swab-types. The choice of the swab has a great impact on the laboratory result. In fact, the swab-type contributes significantly to true positive or false negative detection of nasal MRSA carriage. These findings should be considered when screening a patient.