Biomedical subjects

J Fanghänel

Publications and source records attributed to J Fanghänel.

At least 19 recordsLinked to original sources

PubMed2006

Requirements and infection prophylaxis for internally cooled implant drills.

Implant site preparation is crucially important to long-term success. Heat generation during drilling is unfavourable, since bone is relatively susceptible to heat, depending on its vascularisation and microstructure. Numerous factors such as drilling pressure, number of revolutions, drill design, wear and material, drilling depth and cooling influence heat generation. Internally cooled drills are, therefore, increasingly used, even though the improved cooling effect compared to conventional externally cooled drills is controversial. Internally cooled drills may have the disadvantage of a germ reservoir developing in the cooling channel. This study aimed to examine the effects of disinfection and sterilisation of internally cooled drills. After contamination of the cooling channel with suitable bioindicators (Enterococcus faecium, ATCC 6057 and spores of Bacillus stearothermophilus, ATCC 7953), the drills were disinfected (disinfection solution ID 220, Dürr Dental) and autoclaved (Webeco, E5S90, 134 degrees C, 2.6 bar, 5 min). Disinfection was not completely effective except after pre-cleaning. By means of sterilisation all spores of Bacillus stearothermophilus were completely killed. Internally cooled drills can be successfully disinfected by means of this hygienic procedure routinely used in dental practice and no source of infection is created.

Cold Temperature↗

PubMed2006

The in vitro viability and growth of fibroblasts cultured in the presence of different bone grafting materials (NanoBone and Straumann Bone Ceramic).

Different clinical applications, including dentistry, are making increasing demands on bone grafting material. In the present study we have analysed the viability, proliferation and growth characteristics of fibroblasts cultured in vitro together with two different bone grafting materials, NanoBone and Straumann Bone Ceramic, over a period of 24 and 28 days respectively. Viability was measured at least every 72 hours by using the alamarBlue assay, a test that measures quantitatively cell proliferation and viability but does not require cell fixation or extraction. After one week of culture fibroblast viability was as high as in controls for both grafting materials and remained high (> 90%) for the duration of the experiment. Cell growth was evaluated microscopically. Scanning electron microscopy revealed a dense fibroblast growth at the surface of both bone grafting materials after three weeks of in vitro culture. Generally, our in vitro analyses contribute to further insights into cell - scaffold interactions.

Animals↗

PubMed2006

The morphological and clinical relevance of mandibular and maxillary bone structures for implantation.

Tooth loss, which interrupts the biocybernetic feedback circuit of the masticatory system, changes the structures of the jaw bone: such changes are termed "inactivity atrophy". The mandible is subject to vertical atrophy and the maxilla is primarily subject to horizontal atrophy. The mandible possesses more compact bone, the maxilla more spongy; the resorption directions also differ (mandible: towards the oral aspect; maxilla: towards the vestibular). An implant helps to restore the biocybernetic feedback system. The amount of available bone, bone structure, and topographic conditions are crucial factors influencing implant success. Osseointegration is performed at an early stage (which includes bleeding, granulation tissue, foreign-body recognition, interactions) and at a late stage (so-called osseous bridging, development of fibrous and lamellar bone).

Dental Implantation, Endosseous↗

PubMed2006

Bone functions and the requirements for bone grafts and substitutes in the orofacial region.

Bone is the largest calcium storage, has distinctive plasticity and adaptability and is part of the supporting tissue. An adequate composition is thus necessary. The bone matrix consists of organic and anorganic structures. Osteoblasts, osteoclasts and osteocytes are responsible for bone formation, resorption and metabolism. The periosteum, endosteum and bone tissue are a functional unit and provide protection, nutrition and growth. Bone is subject to continuous remodelling.

Bone Remodeling↗

PubMed2006

Critical considerations on the diagnostic appraisal, adaptation and remodelling of bone graft substitutes.

The diagnostic assessment of skeletal defects has a long-standing tradition. As a result of the development of new bone grafting materials, the demands on diagnostic assessment have also increased. The mode and quality of diagnostic appraisal are crucial to further clinical use and outcome prediction. Alongside traditional clinical and biological techniques, molecular biological methods have gained a broad scope of application and will be used even more frequently in the future.

Bone Substitutes↗

PubMed2006

Histological and fluorescence microscopic examination of the bone/implant interface in orthodontic miniscrews (Mondeal).

The temporary nature of orthodontic implants demands optimisation of size and design in order to minimise damage and risk to the patient. Slender and shorter miniscrews offer the advantage over conventional implants of easier and more ubiquitous positioning with minimised risk of injury to neighbouring anatomical structures such as tooth roots, nerves or vessels. The question is raised, however, as to what extent these advantages are gained at the price of diminished stability or a more unfavourable bone interface. In order to evaluate the screw/bone interface, 14 orthodontic miniscrews (Mondeal Medical Systems, diameter: 1.5 mm, length: 9 mm) were inserted into the right and left mandibles of 7 pigs (Sus scrofa domestica). Bone fluorochromes were administered in a defined order for polychrome sequencing. The samples gathered after 70 days were analysed using histological techniques and fluorescence microscopy. The lower part of the self-tapping thread displayed undisturbed bone apposition. Fluorescence microscopy revealed remodelling and bone apposition within the thread grooves.

Animals↗

PubMed2006

The use of ceramic drills on a zirconium oxide basis in bone preparation.

The favourable mechanical properties and high biocompatibility of the newly developed mixed ceramics composed of zirconium oxide and aluminium oxide have continuously extended the scope of their application. Rotating instruments on a zirconium oxide basis are regarded as superior to metal burs in dentoalveolar surgery in terms of favourable temperature effects on the surrounding bone tissue and the economic advantage that they wear slowly, enabling them to be used repeatedly. In this study ten round burs made of zirconium oxide and aluminium oxide mixed ceramics were used for typical dental-alveolar preparation types on an explanted pig jaw. Prior to the first and following the tenth application a scanning electron microscopic (SEM) analysis of possible wear signs was conducted. However, this revealed no evidence of wear or resulting loss of sharpness.

Aluminum Oxide↗

PubMed2006

Bacterial colonisation of interior implant threads with and without sealing.

Premature loss of dental implants is due, apart from mechanical factors, to germrelated inflammation. Gaps and hollow spaces within the implant system, for example the gap between implant and abutment in the two-part implant system, may provide a bacterial reservoir causing or maintaining inflammation. The bacterial spectrum involved is similar to that found in periodontitis. This in vitro study aimed to scrutinise the capability of Porphyromonas gingivalis (DSM 20709), the bacterium blamed for inducing peri-implantitis, to pass the implant/abutment gap in titanium implant systems used for orthodontic anchorage and to remain vital in the interior. Additionally, the in vitro effectiveness of gutta percha for gap sealing was examined. Twelve titanium implants (Straumann, diameter: 3.3 mm, length 5.5 mm) were provided with abutments at a defined torque (20 Ncm), six of which were sealed with gutta percha before screwing in the abutment. Subsequently the implants were placed in a nutrient solution (thioglycolate boullion with haemin-menadione solution) that contained Porphyromonas gingivalis. Microbiological specimens were sampled from the implant interiors after 24 and 72 hours and analysed using culture methods. There was evidence that penetration of the periodontal pathogen Porphyromonas gingivalis to the implant interior may occur as early as after 24 hours. Microbes were also detected in the interior of implants sealed with gutta percha. The abutment/implant interface in vitro provides a microbiological leakage for the prospective peri-implantitis-inducing bacterium Porphyromonas gingivalis. Survival of the bacterium is possible in the interior, so that development of a bacterial reservoir is assumed. This in vitro trial produced no evidence that sealing with gutta percha is an effective means to prevent secondary bacterial colonisation in the implant interior.

Colony Count, Microbial↗

PubMed2006

The survival and proliferation of fibroblasts on orthodontic miniscrews with different surface treatment: an in vitro study.

It is of fundamental importance for prosthodontic and orthodontic applications that there is a short osseointegration time of dental implants without inflammation of the surrounding tissue. In addition to the chemical properties of the implant material, the surface morphology is an equally critical parameter. The objective of this work was to study the effect of two simple surface treatments on the survival and proliferation of fibroblasts. Three groups of orthodontic miniscrews (Mondeal) were used. One group was given an airflow (EMS, Schweiz) treatment, the second was sand-blasted in the area of the threading and a third group served as a control. After preparation sterilised screws were cultured in vitro with fibroblasts (L-929). The metabolic cell activity on the implant surface was determined after 24, 48 and 120 hours using the alamarBlue assay and a count of DAPI labelled fibroblasts was performed with a fluorescence microscope. After 24 hours, but not at 48 hours and 120 hours, the metabolic activity of the fibroblasts was slightly decreased for the airflow screw group. Generally, no significant difference was found regarding metabolic activity and proliferation of fibroblasts within the different groups.

Bone Screws↗

PubMed2006

The application of bone graft substitutes for alveolar ridge preservation after orthodontic extractions and for augmentation of residual cleft defects.

The use of bone substitute materials in orthodontics is to be considered prior to orthodontic space closure after tooth extraction during the treatment of marked crowding as well as for treatment of residual defects in cleft-lip-and-palate children. In both cases the common objective is structure preservation or augmentation of the alveolar ridge. The demands to be made on the synthetic bone graft substitute comprise not just complication-free and safe use but also the chance of early tooth movement into the treated defect area with sufficient stability of the new tooth position.

Alveolar Ridge Augmentation↗

PubMed2006

Wound management after the application of bone grafting substitutes in the orofacial region.

Surgical dressing after the application of bone grafting material depends on the type and size of the defect. A complete and tension-free wound closure has proved to be successful. In this context the infection problem needs special attention. Bone graft substitutes with an adequate surface structure, porosity and chemical properties, in combination with sufficient blood circulation, hold osteoconductive potential. They serve as a guide rail for the osteoblast-induced formation of new bone tissue, which at best may lead to complete replacement of the grafting material.

Alveolar Ridge Augmentation↗

PubMed2005

Pain during prophylaxis treatment elicited by two power-driven instruments.

BACKGROUND: Sonic scalers have an elliptical and piezoceramic ultrasonic scalers a linear oscillation pattern. Thus, a sonic scaler "hammers" the tooth surface, irrespective of its alignment to the tooth, whereas a piezoceramic ultrasonic scaler may oscillate parallel to the tooth surface and gently remove calculus if the alignment is correct. The aim of this study was to measure pain on a visual analogue scale (VAS) during removal of supragingival calculus on mandibular incisors with a sonic or an ultrasonic scaler. MATERIAL AND METHODS: Seventy-four periodontally healthy subjects with supragingival calculus on the mandibular incisors were treated with both a sonic and a piezoceramic ultrasonic scaler in a split-mouth design. The sequence of instrument application and allocation of instruments to jaw side were randomized. Patient comfort was assessed with a VAS after treatment. RESULTS: The VAS results did not show any difference between the two instrumentation modalities. CONCLUSION: For calculus removal during prophylaxis the type of power-driven instrument does not seem to have an impact on perceived pain. This means that the oscillation pattern does not influence the pain experience.

Adult↗

PubMed2004

Do folic acid and thiocyanate have a preventive effect on exogenously induced disturbances of embryonic cranial development?

The preventive influence of folic acid and thiocyanate on procarbazine-induced disturbances of embryonic cranial development was investigated on experimental animals. Low dosages of folic acid or thiocyanate demonstrated no prophylactic effect. When thiocyanate was administered alone, an increased cleft rate was unexpectedly found for the secondary palate. The combined application of folic acid and thiocyanate showed a cleft-prophylactic effect in the secondary palate in addition to growth protection in the primary palate. It can be assumed that thiocyanate has a positive effect on chondral and osseous growth of the palate during the post-sensitive phase of embryogenesis, while in the sensitive phase, it can function as a carrier for teratogenous and toxic substances.

Animals↗

PubMed2004

Novel mutations in the cathepsin C gene in patients with pre-pubertal aggressive periodontitis and Papillon-Lefèvre syndrome.

Aggressive periodontitis (AP) in pre-pubertal children is often associated with genetic disorders like Papillon-Lefèvre syndrome (PLS). PLS is caused by mutations in the cathepsin C (CTSC) gene. We report a novel CTSC mutation (c.566-572del) in an otherwise healthy AP child and two novel compound heterozygous mutations (c.947T>G, c.1268G>C) in a PLS patient. We conclude that at least a subset of pre-pubertal AP is due to CTSC mutations and therefore may be an allelic variant of PLS.

Adolescent↗

PubMed2003

A study on the effect of inhalative formaldehyde exposure on water labyrinth test performance in rats.

We investigated the effects of repeated inhalative exposure to several formaldehyde concentrations (2 hours/day, 10 consecutive days) on the behavior of adult male and female LEW.1K rats during a period in which they learned to perform a water labyrinth task. We also examined the effects on the histology of some organ tissues. While the controls needed increasingly shorter swimming periods to complete the water labyrinth test and made fewer errors with advancing trial duration, such progress could not be observed in the learning behavior of the exposed animals. They took significantly longer swimming periods to reach the finish and made significantly more errors in comparison to the controls. The statistical comparison between the collected data in the formaldehyde exposed male and female rats reveals that females in general reached the end point of the swimming labyrinth in significantly less time. On some trial days, however, they made more mistakes than males. In the highest concentration group, no gender differences were evident in the frequency of errors. The histological examination revealed no pathological changes attributable to formaldehyde exposure. Since the water labyrinth test is used to investigate changes in memory and learning behavior in animals, we conclude that under investigational conditions, formaldehyde affects the learning behavior and the memory of male and female rats.

Administration, Inhalation↗

PubMed2003

Effects of prenatal procarbazine administration on intrauterine development in rats.

The effects of prenatal procarbazine (PCZ) administration on the intrauterine development of rat fetuses were investigated. Gravid rats were treated on day 14 of gestation (GD14) with 25 mg or 50 mg/kg body weight PCZ via stomach tube. Controls received normal saline in the same dosis and manner. On GD20, all fetuses were collected by caesarian section. Live and dead fetuses as well as resorptions were counted. In the live fetuses, the following investigations were conducted: measurement of body weight, occipito-coccygeal-lenght (OCL), tail length (TL), placental weight and diameter, external macroscopic and binocular microscopic examination, and sectional analysis of the animals using the razorblade sectioning technique. Both PCZ doses caused a significant reduction in the number of live fetuses and a significant increase in resorptions. Mean body weight in PCZ groups was antidromic affected. OCL and TL were significantly depressed. Placental weight and diameter as well as number of dead fetuses were comparable to those of controls. External and sectional investigations revealed no PCZ-related deviations. In the light of our findings we conclude that PCZ in the doses used in this experimental study significantly affects the intrauterine development in rats in terms of fetal toxicity but displays no teratological properties.

Animals↗

PubMed2003

Sex-related differences in procarbazine-induced cleft palate and microgenia and the anti-teratogenic effect of prenatal folic acid supplementation in rats.

Sex-related differences in the frequency of cleft palates and microgenia in rat fetuses prenatally treated with procarbazine (200 mg/kg on day 14 of gestation (GD14), group 1), and the anti-teratogenic effect of prenatal folic acid supplementation (4 mg/kg on GD14 through GD17, group 2) were studied in LEW.1A rats. In group 1, complete clefts were observed in 69% of the male and in 36% of the female fetuses while incomplete clefts (present only in the hard palate) were exhibited by 31% of the males and 43% of the females. Microgenia occurred in all males but only in 64% of the female fetuses. In group 2, the prenatal folic acid supplementation significantly reduced the occurrence frequency of complete clefts to 9% in males and to 0% in females. In contrast, incomplete clefts increased to 82% in males and 91% in females. Microgenias were reduced to 73% and 57% in male and female fetuses, respectively. Since incomplete clefts present in the hard palate are assumed to be residues of spontaneous intra-uterine repair processes of exogenously induced complete palatal clefts, we conclude that prenatal supplementation with folic acid at a dose of 4 mg/kg promotes the intra-uterine repair of cleft palates and offers a partial protection against procarbazine teratogenicity. Furthermore, it is deduced that gender-specific differences exist in the susceptibility to procarbazine and in the anti-teratogenic effect of folic acid on procarbazine-induced microgenia.

Animals↗

PubMed2003

Formaldehyde inhalation & open field behaviour in rats.

BACKGROUND & OBJECTIVES: It has been shown in animal studies that repeated exposure to formaldehyde vapour alters behaviour and memory. Since information is not available on the behavioural consequences of acute formaldehyde exposure, this study was conducted to investigate the influence of single inhalative exposure to formaldehyde on the explorative and locomotor behaviour of adult male and female rats. METHODS: Rats were exposed to different concentrations of formaldehyde vapour (0.5, 1.0, 2.5%, corresponding to inhalation chamber concentrations of 1.0, 2.5, and 5.0 ppm, respectively) for 2 h and an open field test was carried out 2 h after the end of exposure (first test) and repeated 24 h thereafter (second test). The parameters examined were crossing of floor squares, sniffing, grooming, rearing, climbing, and defaecation. RESULTS: In exposed male rats, significant reduction of crossed floor squares, grooming, and wall climbing, and increase in floor sniffing and rearing were observed in the first test. During the second test, males in the groups exposed to 2.5 ppm and 5 ppm crossed significantly higher numbers of squares when compared to controls. Air sniffing, wall climbing, and rearing were altered in all exposed males. Control males showed higher incidence of defaecation in comparison to the values of first test. The formaldehyde-exposed female rats crossed significantly decreased numbers of floor squares in the first test. In females in the 2.5 ppm and 5 ppm groups, decreased grooming and enhanced floor sniffing were observed. In the second test, all exposed females crossed higher numbers of floor squares than controls. Frequencies of air and floor sniffing were higher in females exposed to 2.5 ppm and lower in those exposed to 1 ppm. Defaecation was enhanced in females in the 2.5 ppm group in comparison to the first test. INTERPRETATION & CONCLUSION: The results show that formaldehyde inhalation in the concentrations and duration of exposure used in the present experiments significantly influences the locomotor and explorative behaviour of rats after a single exposure in a gender-related manner and that various behavioural components in the exposed animals remains altered even after 24 h.

Animals↗