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M Wichmann

Publications and source records attributed to M Wichmann.

At least 19 recordsLinked to original sources
PubMed2007

Comparison between computer-aided testing and traditional multiple choice: an equivalence study.

AIMS: Computer-aided learning (CAL) is a viable alternative to traditional teaching methods. While CAL is used for teaching only, computer-aided testing (CAT) can be applied as a computer-based examination method. The aim of the present study was to compare the performance of undergraduate students in computer-interactive tests and traditional multiple choice tests and to evaluate the influence of question length and language skills on test results. MATERIALS AND METHODS: Fifty-two native German-speaking students and five non-native speaking students were randomly assigned to two groups. They were required to answer 20 conventional multiple choice questions and 20 questions using the interactive MobiTed system. An analysis of variance and t-tests (alpha = 0.05) were used to compare scores. RESULTS: Non-native speakers scored significantly lower on the interactive test compared with the native speaking students (P = 0.048 for long questions and P = 0.003 for short questions). There were no significant group differences on the conventional multiple choice test (P = 0.052 for long questions and P = 0.089 for short questions). Based on the results of the native speaking students neither test method nor question length had an influence on overall performance. CONCLUSION: Interactive multiple choice tests may provide an alternative to written tests, especially when considering time expenditure. Language skills and question length should be taken into account when setting time limits for examination.

Computer-Assisted Instruction↗
PubMed2006

Expression of interleukin 1-beta, transforming growth factor beta-1, and vascular endothelial growth factor in soft tissue over the implant before uncovering.

BACKGROUND: Overexpression of inflammatory cytokines interleukin 1-beta (IL-1beta), transforming growth factor beta-1 (TGF-beta1), and vascular endothelial growth factor (VEGF) may cause healing impairment following implant insertion, jeopardizing success especially in patients previously irradiated. Limited data is available regarding expression pattern of inflammatory cytokines in peri-implant soft tissue caused by the surgical intervention itself. STUDY DESIGN: This study examined 21 patients receiving dental implants. Biopsies of peri-implant tissue were harvested at re-entry 4 months after initial surgery. Eight patients underwent probing of untreated mucosa. Three groups were created (group 1: regular peri-implant mucosa; group 2: patients with irradiated peri-implant mucosa, radiation treatment due to oral squamous cell cancer; group 3: control). Immunohistochemical staining was performed for TGFss1, IL-1ss, and VEGF. RESULTS: Following the placement of dental implants (group 1 vs group 3) a significant increase (P > .05) in TGF-beta1, IL-1beta, and VEGF expression in the peri-implant mucosa was demonstrated. No alteration of this distinct pattern was found for previously irradiated tissue (group 1 vs. group 2). CONCLUSIONS: The study highlights the fundamental involvement of TGF-beta1, IL-1beta, and VEGF during the regeneration of peri-implant soft tissue structures. The use of extended interim solutions may be one clinical implication of these prolonged tissue remodeling processes.

Adolescent↗
PubMed2006

Changes in neurophysiologic parameters in a patient with dental anxiety by hypnosis during surgical treatment.

It was hypothesized that dental anxiety, which leads to neurophysiologic alterations in heart rate, respiratory rate and blood pressure prior, during and subsequent to dental treatment, can be influenced by medical hypnosis. We report the positive impact from non-invasive hypno-sedation during dental implant surgery on a 54-year-old female patient who experienced neurophysiologic reactions as a result of the psychosomatic process of dental anxiety (dental anxiety scale value = 13). The neurophysiologic changes during dental surgery performed with and without hypnosis were compared after the patient underwent the same surgical treatment protocol. This case report was part of a study designed to evaluate hypnosis as a non-invasive therapy for dental-anxious patients over six sessions using subjective experience and objective parameters, which included electroencephalogram, electrocardiogram, heart rate, blood pressure, oxygen saturation of the blood, respiration rate, salivary cortisol concentration and body temperature.

Blood Pressure↗
PubMed2006

Dental anxiety--an epidemiological study on its clinical correlation and effects on oral health.

Pronounced dental anxiety could lead to avoidance strategies to evade dental visits. The aim of the present epidemiological study was to investigate the prevalence and related oral disease patterns of dental anxiety in young adult male soldiers. Therefore, the intensity and frequency of dental anxiety are presented and the correlation with oral clinical findings are evaluated. Three hundred seventy-four soldiers who underwent a compulsory dental check-up were randomly assigned to this study. Psychological parameters were collected based on a protocol integrating the Dental Anxiety Scale (DAS) and the Gatchell Fear Scale (GaFS). Patient-based measures included D3,4MF-scores for dental status and the Community Periodontal Index of Treatment Need (CPITN) for periodontal status. Thirty-two individuals (8.6%) showed DAS-scores of 13 or 14 (anxious), while 4.6% had a DAS-score > or = 15 (highly anxious/phobic). Highest DAS-values were measured among patients' aged 19-29 (n = 262). DMFS-values of anxious and less anxious patients showed only minor differences. However, anxious patients had significantly more carious lesions (P < 0.001). CPITN periodontal values showed no significant differences between both groups. 89.2% of less anxious individuals and 79.6% of anxious patients went for regular dental check-ups. Thus, every tenth patient was considered to have high dental anxiety. Anxiety results in avoidance behaviour, which can only be discovered upon compulsory examinations and which is associated with higher caries morbidity and need for oral rehabilitation. As anxiety has a direct influence on oral health, it should be detected and accounted for in a treatment concept integrating dental and cognitive-behavioural therapeutic approaches.

Adult↗
PubMed2005

[Assessment of the tetanus immune status in plasma donors of the Blood Donor Service of the Bavarian Red Cross].

BACKGROUND AND OBJECTIVE: Tetanus is nowadays largely under control, as a result of the preventive immunization programme. This prophylactic measure is important also because there is no specific treatment. In Germany tetanus occurs almost exclusively in elderly, not adequately immunized persons. This study determined the existing immune status of plasma donors in the region of Ingolstadt, Bavaria. SUBJECTS AND METHODS: Tetanus IgG antibody concentrations were measured with the ELISA test in serum of 1742 plasma donors (891 women, 851 men, age range 18-64 years). RESULTS: An adequately protective immunity against tetanus was found in 98.7% of men and 94.1% of women, while 5 women and 3 men had no protection. Demographic data indicated that the immunization protected males longer than females, regardless of age, especially in those over 50 years of age (85% of females, 99% of males). CONCLUSION: Adequate tetanus protection was achieved in the overwhelming majority of test subjects. This demonstrates that the prevalence of protection is lower in females than in males, a difference most marked in those over 50 years of age. It is important that this age group in particular should, as part of health care, be informed by their medical practitioner of the dangers of tetanus and the advantages of immunization.

Adolescent↗
PubMed2005

The aesthetics of all-ceramic veneered and monolithic CAD/CAM crowns.

The aim of this study was to examine whether crowns fabricated from machinable blocks would achieve acceptable aesthetics and whether these could compete with the aesthetics of restorations obtained by individual layering technique. Fourteen patients, who were to receive single anterior crown restorations, participated in this study. For each person two kinds of crowns were provided: one crown was made with the Cergogold system. The second one was produced in a Cerec machine and was additionally stained. Three independent examiners assessed the aesthetic appearance of crowns fabricated to match each subject's anterior shade. A scale of 1-6 was used to assess the aesthetic adaptation of each crown, with 1 representing excellent characteristics and 3.5 marking the threshold for clinical acceptability. The examiners' scores were averaged, and the mean values were analysed with the Wilcoxon signed rank test (P<or=0.05). Regardless of the fabrication method the crowns were aesthetically acceptable in all 14 patients. The mean values for the layering technique and for the machined restorations did not differ significantly. Within the limits of this study it was documented, that machinable blocks could attain aesthetically satisfying results.

Ceramics↗
PubMed2005

Zinc gluconate in the treatment of dysgeusia--a randomized clinical trial.

In the treatment of dysgeusia, the use of zinc has been frequently tried, with equivocal results. The aim of the present randomized clinical trial, which involved a sufficiently large sample, was therefore to determine the efficacy of zinc treatment. Fifty patients with idiopathic dysgeusia were carefully selected. Zinc gluconate (140 mg/day; n=26) or placebo (lactose; n=24) was randomly assigned to the patients. The patients on zinc improved in terms of gustatory function (p <0.001) and rated the dysgeusia as being less severe (p <0.05). Similarly, signs of depression in the zinc group were less severe (Beck Depression Inventory, p <0.05; mood scale, p <0.05). With the exception of the salivary calcium level, which was higher in the zinc patients (p <0.05), no other significant group differences were found. In conclusion, zinc appears to improve general gustatory function and, consequently, general mood scores in dysgeusia patients.

Adult↗
PubMed2005

The self-adjusting crown (SAC).

When previously using Cerec 3D, the occlusal surface could be designed according to morphologically functional aspects with the aid of a bite registration (static and/or dynamic). In addition, different tooth databases could be used for the design of crowns. However, the relevant design suggestion had then to be manually aligned onto the functional registration by the user. The new Cerec 3D software version R 2005 now promises the automatic adjustment of crown proposals in alignment with the corresponding functional registration. In this case, the crown design selected from the tooth databases is adjusted to the morphology of the functional registration and is therefore modified until light contact points are still present. The procedure of the "self-adjusting crown" is demonstrated by reference to a clinical case. As the name "self-adjusting crown" indicates, this automatic tool is possible only in restorations which have a single-segment preparation margin (crowns).

Adult↗
PubMed2004

Differences between the Cerec-3D software versions 1000 and 1500.

The Cerec-3D software was introduced officially at the IDS 2003 with the version 2.00 R1000. The decisive difference compared with the preceding software generations was that the prepared tooth and the restoration were displayed three dimensionally. Thus, the virtual changes which could be made with the aid of editing tools could also be controlled and seen immediately in 3D. The latest officially available version of the Cerec-3D software version 2.10 R1500 differs in some further developments from the first version 2.00 R1000; these are for example: --If the semiautomatic margin detector is switched off while marking the preparation margin, the alternative intensity image appears instead of the 3D display. --Designing has been decisively improved by the extension of the "Drop" tool (function of continuous application and removal of material). --Under morphologically difficult circumstances, the design proposal can be magnified/reduced in size and repositioned in all spatial directions. --The Parameter setting again permits setting an adhesive gap width specific to the dentist and unit. As an example, the version 1500 software is demonstrated on a simple clinical case in which the occlusion points were defined virtually with the aid of a functional bite registration, eliminating the need for occlusal grinding-in.

Computer-Aided Design↗
PubMed2004

Generation of functional Cerec 3D occlusal surfaces: a comparison of two production methods relevant in practice.

The introduction of the Cerec 3D software (R 1500) promised the generation of functional occlusion points and proximal contacts on the basis of a 3-dimensional virtual model on the screen. The objective of this in vitro study was to check this claim in the simulated chairside production of a single tooth restoration. Furthermore, the differences both in conventional finishing and in ceramic glazing were to be determined. For the operator, the latter should simplify or shorten the intraoral finishing and polishing of the occlusal surface, or make it superfluous. To check the suitability of the two methods, these were compared with regard to their quality and the time required to perform them. Ten cavities on articulated models, representing real clinical cases, were each provided with two restorations. One was produced with the glazing method (group A), the other conventionally (group B). The Cerec 3D software, version R 1500, was used for designing the restoration. The restorations made from Vita Mark II ceramic blocks were finished with fine diamond instruments and polished with Sof-Lex disks when using the conventional method. In the alternative method, finishing was practically replaced by glazing the surface. The restorations were evaluated in the articulator, considering both the vertical relation at the incisal pin as well as the accurate position of the contact points. The study showed that functional rehabilitation was possible and no significant qualitative differences occurred in the methods. In this in vitro study, it was found that the glazing method reduced the time required by the operator by around 20% and indicates an improvement in quality. The results of this study promise simplification when the glazing method is used clinically.

Computer Simulation↗
PubMed2003

[Surgical treatment of pulmonary metastases from renal cancer].

Based on a large single-center follow-up database, we evaluated the long-term results after curative resection of pulmonary metastases from renal cancer. During a 20-year period, 105 patients underwent a total of 150 resections with curative intention. Hospital mortality was 0.95%, 5- and 10-year survival rates were 40% and 33%, respectively. Significant prognostic relevance was shown for complete pulmonary resection, lymph node involvement upon primary resection as well as size of the resected lung metastasis. Our findings of low perioperative morbidity and mortality rates lead us to propose that in patients without additional metastases curative resection of pulmonary lesions should be considered. Moreover, recurrent pulmonary metastases should also be considered for surgical treatment since resection for cure significantly improves survival in these patients.

Adult↗
PubMed2003

[Preoperative fasting. An update].

In Germany the predominant standard of preoperative care for elective surgery is fasting after midnight, with the aim of reducing the risk of pulmonary aspiration. However, for the past several years the scientific evidence supporting such a practice has been challenged. Experimental and clinical studies prove a reliable gastric emptying within 2 h suggesting that, particularly for limited intake of clear fluids up to 2 h preoperatively, there would be no increased risk for the patient. In addition, the general incidence of pulmonary aspiration during general anaesthesia (before induction, during surgery and during recovery) is extremely low, has a good prognosis and is more a consequence of insufficient airway protection and/or inadequate anaesthetic depth rather than due to the patient's fasting state. Therefore, primarily to decrease perioperative discomfort for patients, several national anaesthesia societies have changed their guidelines for preoperative fasting. They recommend a more liberal policy regarding per os intake of both liquid and solid food, with consideration of certain conditions and contraindications. The following article reviews the literature and gives an overview of the scientific background on which the national guidelines are based. The intention of this review is to propose recommendations for preoperative fasting regarding clear fluids for Germany as well.

Fasting↗
PubMed2003

[Experimental examination concerning the efficacy of silver-coated Dacron prostheses in vascular graft infections following subcutaneous implantation in a standardized infection model].

UNLABELLED: It was the aim of the study to examine the efficacy of silver coated prostheses in comparison to Rifampin in impregnated prostheses in the prevention of vascular graft infections. MATERIAL AND METHODS: 24 C3H/HcN mice with a bodyweight between 24 and 27 grams were assigned to four different groups. GROUP I: control gel-sealed Dacron graft (Uni-Graft DV) (6), GROUP II: gel-sealed Dacron graft (Uni-Graft DV) contaminated locally with 2 x 10(7) CFU/1.2 ml Staphylococcus aureus ATCC 25923 (6), GROUP III: silver prosthesis (Intergard Silver) contaminated locally with 2 x 10(7) CFU/0.2 ml Staphylococcus aureus ATCC 25923 (6), GROUP IV: Rifampin impregnated prosthesis contaminated locally with 2 x 10(7) CFU/0.2 ml Staphylococcus aureus ATCC 25923 (6). 14 days after primary operation all animals were euthanized and the grafts harvested. Specimens were examined for signs of infections by histology and microbiology. RESULTS: At termination of the trial on day 14 none of the grafts of group I were contaminated. 6 out of 6 grafts in group II, 6 out of 6 grafts in group III and 1 out of 6 grafts in group IV presented with infected grafts. The use of antimicrobial Rifampin could significantly prevent infection after bacterial challenge in group IV. CONCLUSION: The silver protected prosthesis (Intergard Silver) seems to be not effective in protecting vascular infection in vivo. However, the Rifampin group showed excellent results. In conclusion Rifampin bonded gelatin-sealed Dacron grafts are significantly more resistant to bacteremic infection than are silver/collagen-coated Dacron grafts.

Animals↗
PubMed1999

[Endosseous implants for functional masticatory rehabilitation in the extremely atrophied edentulous maxilla].

PURPOSE: The aim of this retrospective study was to evaluate the long-term survival rate of dental implants in edentulous patients suffering from severe atrophy of the alveolar ridges in the upper jaw. PATIENTS AND METHODS: In total, 964 implants were inserted in 140 patients. A total of 481 implants were combined with an osteoplastic augmentation of the maxilla, and 483 implants were inserted directly in the atrophic bone. The success rate was determined using survival analysis, log rank tests and a Cox regression analysis. RESULTS: The overall survival rate for all implants was 42.2% during an observation period of 11 years. Between implants combined with an osteoplasty and implants inserted in local bone tissue there were no significant differences in the survival rate. The survival rate of implants combined with an osteoplasty was significantly reduced in women and in the case of repeated insertion or augmentation. Interestingly, a few of the patients treated with an osteoplasty demonstrated high numbers of individual implant failures. Those patients were postmenopausal women exclusively. Among them there is probably a certain group with a very high risk of implant failures. CONCLUSION: This study shows that oral rehabilitation with osteointegrated implants in patients with severely atrophic alveolar ridges in the upper jaw is still problematic.

Alveolar Bone Loss↗
PubMed1999

Long-term results of endosteal implants used for restoration of oral function after oncologic surgery.

The aim of the present study was to analyse the long-term survival rate of endosteal implants used for restoration of oral function in patients having undergone oncologic surgery. Eighty-three consecutive patients, who had received a total of 409 endosteal implants ad modum Brånemark, subsequent to resections of soft tissue and bone during ablation of oral malignancies, were enrolled into the study. A life-table analysis was used to determine the survival rate of the implants placed during a period of 13 years. Log rank tests and Cox regression analysis were employed to identify relevant effects of surgical parameters on implant survival. A total of 38 implant failures were encountered. Most of the losses (n = 19) occurred during the first year of functional loading. Subsequent failures were evenly distributed across the remaining follow-up period. The cumulative overall survival rate of implants was 56.5%. Previous radiation therapy, insertion into grafted bone or original jaw bone and the technique of grafting did not significantly affect the survival rates. In the Cox regression analysis, the timing of implant placement in the group of patients with bone grafts (primary vs. secondary placement) was significantly related to the survival rate (P = 0.0197), with a lower survival rate of 36.2% for primary insertion of implants and 67.1% for secondary placement.

Adolescent↗
PubMed1997

Survival analysis of endosseous implants in bone grafts used for the treatment of severe alveolar ridge atrophy.

PURPOSE: The aim of the current study was to evaluate the long-term results of endosseous implants placed into autogenous bone grafts in severely atrophic alveolar ridges. PATIENTS AND METHODS: A total of 871 implants were placed in 137 patients. The success rate was determined using survival analysis, log rank tests, and a cox regression analysis. RESULTS: Seventy-four implant failures were encountered in 23 patients. Most implants were lost because of a lack of osseointegration at the time of abutment connection or by asymptomatic loosening during the first months thereafter. The overall 1-year cumulative survival rate (CSR) was 83.4%, with a decrease to 67.8% after 5 years. The only parameter of prognostic relevance in the multivariate analysis of the whole study population was the patients' gender, with a significantly worse prognosis in female patients (5-year CSR, 62.3%). However, when the patients were divided into edentulous and partially edentulous jaws, a change was observed in the overall significance of the parameters introduced into the analysis. In edentulous patients, the maxilla appeared to over-rule all other parameters, with a 5-year cumulative survival rate of 48.8%, whereas the mandible presented a significantly higher rate of implant survival (5-year CSR, 89.3%). CONCLUSION: This study shows a poorer success rate in females than in males, probably because of differences in the quality of the bone grafts.

Adolescent↗
PubMed1996

Postoperative function after implant insertion in vascularized bone grafts in maxilla and mandible.

Between 1988 and 1992, 80 Brånemark-type implants were inserted in 18 patients during reconstruction of the mandible or maxilla with vascularized iliac crest or scapula grafts with or without additional soft tissue pedicles. In these procedures, nine vascularized bone grafts were combined with a primary insertion of 32 implants and a secondary insertion of 48 implants. Twelve patients are currently wearing the implant-borne dentures. From 32 implants inserted primarily, eight could not be used for prosthodontic rehabilitation because three were lost with a graft, three were left as sleepers, and two demonstrated a lack of osseointegration. None of the implants inserted secondarily in grafts were lost. Primary implant insertion should be performed only in close cooperation with the prosthodontist and in selected cases, for example, in free-end reconstruction of the mandible with a straight graft and where a limited number of implants is needed. Although restoration of masticatory function in patients with head and neck cancer can be achieved, compared with a healthy control group, functional impairments remain. Patients subjectively favor the nonreconstructed side of the mandible or maxilla for chewing. These findings can be correlated with a postoperative follow-up investigation using a miniature force transducer and the T-scan system.

Denture, Partial↗