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Biomedical subjects

E Reich

Publications and source records attributed to E Reich.

At least 37 records · Page 2Linked to original sources
PubMed2000

The influence of a 0.2% chlorhexidine mouthrinse on plaque regrowth in orthodontic patients. A randomized prospective study. Part II: Bacteriological parameters.

In a prospective plaque regrowth study focusing on oral hygiene during fixed appliance therapy 12 adolescent patients (mean age 14.1 +/- 1.5 years) were evaluated twice over 2-day test periods. In the randomized, double-blind study the influences of a 0.2% chlorhexidine mouthrinse (Corsodyl, CHX) and a commercially available dentifrice supplementing fluoride (Odol-med-3) were compared intra- and interindividually in a crossover design with regard to the bacteriological parameters. The bacteriological parameters of vital fluorescence, bacteriological counts (BC), colony forming units (CFU), plating efficiency (PE) and mutans streptococci (MS) were related to the clinically assessed indices of plaque and gingivitis. All parameters analyzed demonstrated significant differences between the control and the test (chlorhexidine) group. Where-as the values of BC, CFU, and PE progressively increased in the control group from T0 to T2, these parameters distinctly decreased in the chlorhexidine group. All values of vital flora (VF) scored around 75% in the control group compared to values of 30% in the test group. BC, CFU und PE correlated significantly. The score of mutans streptococci persisted or increased in the controls whereas mutans streptococci approached 0 in the chlorhexidine group. Until the 5th day of washout a clear-cut carry over of the chlorhexidine rinse on mutans streptococci as well as on the gingival index was evident. Since dead microorganisms remain on the tooth surface and in order to maintain oral health, chlorhexidine application might advisedly be supplemented by mechanical plaque control.

Adolescent↗
PubMed2000

The influence of a 0.2% chlorhexidine mouthrinse on plaque regrowth in orthodontic patients. A randomized prospective study. Part I: clinical parameters.

In a prospective plaque regrowth study focusing on oral hygiene during fixed appliance therapy 12 adolescent patients (mean age 14.1 +/- 1.5 years) were evaluated twice over 2-day test periods. In the randomized, double-blind study the influence of a 0.2% chlorhexidine (CHX) mouthrinse (Corsodyl) and a commercially available dentifrice supplementing fluoride (Odol-med-3) were compared intra- and interindividually in a crossover design with regard to plaque and gingivitis. Before starting the first test phase there was a 14-day preliminary phase for upgrading the oral hygiene. Between the 2 test phases was a 5-day "washout". On the last day of the second test phase the patients were asked to fill in a questionnaire concerning their experiences during the study. The 0.2% Corsodyl reduced the plaque index scores significantly (p < 0.001). The gingival index revealed a similar reduction (2nd day of test: p = 0.03). Until the 5th day of washout a clear-cut carryover effect of the chlorhexidine rinse on the gingival index was observed. Both the lower mean values of the 2 clinical parameters at the beginning of the test phases as compared with those at the beginning of the preliminary phase and the evaluation of the questionnaires indicated a possible Hawthorne effect. 0.2% Corsodyl may be employed as an adjunct to other preventive measures such as professional care and patient-oriented instruction on an intermittent basis in order to reduce the plaque-induced iatrogenic side effects and to enhance the efficacy of oral hygiene measures in connection with orthodontic therapy with fixed appliances.

Adolescent↗
PubMed2000

Healing of fenestration-type defects following treatment with guided tissue regeneration or enamel matrix proteins. An experimental study in monkeys.

The aim of the present study was to evaluate histologically in monkeys the healing in acute fenestration-type defects following treatment with guided tissue regeneration (GTR) or enamel matrix proteins (EMD). Standardized "critical size" fenestration-type defects were produced surgically at the vestibular aspect of teeth 13, 23, 33, 43 in three monkeys (Macaca fascicularis). The vestibular bone plates were removed and the root surfaces were debrided by means of hand instruments in order to completely remove the root cementum. Following root conditioning with ethylenediaminetetraacetate (EDTA), the defects were treated using one of the following therapies: (1) GTR, (2) EMD, or (3) control (coronally repositioned flaps). After 5 months the animals were killed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA, and embedded in paraffin. Eight-micrometer-thick step serial histological sections were cut in a vestibulo-oral direction, stained with hematoxylin and eosin or oxone-aldehyde-fuchsin-Halmi, and subsequently examined under the light microscope. The results showed that, in the defects treated with GTR, a new connective tissue attachment (i.e., new cementum with inserting collagen fibers) and new bone formation had consistently occurred, whereas, in the defects treated with EMD or with coronally repositioned flaps, new attachment and new bone reformed to a varying extent. The quality of the cementum did not differ after EMD, GTR, or flap surgery. It was concluded that GTR treatment with bioresorbable membranes seems to predictably promote new attachment and new bone formation, whereas the application of EDTA or EMD may also enhance periodontal healing to a certain extent. Further studies with higher numbers of animals and defects are needed in order to definitely clarify the effect of root surface conditioning with EDTA and EMD on periodontal healing.

Absorbable Implants↗
PubMed2000

Clinical and antibacterial effect of tea tree oil--a pilot study.

The aim of this clinical pilot study was to compare the effect of tea tree oil with the effect of water and chlorhexidine on supragingival plaque formation and vitality. Eight subjects were asked to refrain from any kind of mechanical oral hygiene for 4 days after professional tooth cleaning (day 0), and to rinse with water instead for 1 week, with chlorhexidine in a second and tea tree oil in a third test week. The plaque index (PI), which was evaluated daily (days 1-4), served as a clinical control parameter. On the last day of the study (day 4), the plaque covering the front teeth was stained, photographed, and therefrom the plaque area (PA; %) was estimated using a digital measuring system. Each day of the study (days 1-4), the sampled plaque was examined using a vital fluorescence technique. Tea tree oil reduced neither the clinical parameters (PI and PA) nor the vitality of the plaque flora significantly. Within the limitations of the study design, it was determined that a solution with tea tree oil--utilized as ordinary mouthwash--has no positive effect on the quantity or quality of supragingival plaque.

Adult↗
PubMed2000

Treatment of intrabony defects with guided tissue regeneration and enamel-matrix-proteins. An experimental study in monkeys.

BACKGROUND: Enamel matrix proteins (EMD) have recently been introduced in regenerative periodontal treatment. However, no histological data are yet available concerning the effect of treating intrabony periodontal defects with EMD, and no histological comparisons have been made comparing the result of treatment of intrabony defects with EMD with that of the treatment with guided tissue regeneration (GTR). AIM: Therefore, the aim of the present study was to evaluate histologically in monkeys the effect of treating intrabony defects with EMD, GTR or combined EMD and GTR. METHOD: Intrabony periodontal defects were produced surgically at the distal aspect of teeth 14, 11, 21, 24, 34, 31, 41 and 44 in 3 monkeys (Macaca fascicularis). In order to prevent spontaneous healing and to enhance plaque accumulation metal strips were placed into the defects. After 6 weeks the defects were exposed using a full-thickness flap procedure. The granulation tissue was removed and the root surfaces were debrided by means of hand instruments. Subsequently, the defects were treated using one of the following therapies: (i) GTR, (ii) EMD, or (iii) combination of EMD and GTR. The control defects were treated with coronally repositioned flaps. After 5 months, the animals were sacrificed and perfused with 10% buffered formalin for fixation. Specimens containing the defects and surrounding tissues were dissected free, decalcified in EDTA and embedded in paraffin. 8 microm thick histological sections were cut and stained and subsequently examined under the light microscope. RESULTS: In the control specimens, the healing was characterized by a long junctional epithelium and limited periodontal regeneration (i.e., new periodontal ligament, new cementum with inserting connective tissue fibers and new bone) in the bottom of the defect. The GTR-treated defects consistently presented periodontal regeneration when the membranes were not exposed whereas the sites treated only with EMD presented regeneration to a varying extent. The combined therapy did not seem to improve the results. CONCLUSION: It can be concluded that all 3 treatment modalities favor periodontal regeneration.

Alveolar Bone Loss↗
PubMed2000

Does pretreatment of cavities effectively promote good marginal adaptation of glass-ionomer cements?

PURPOSE: The aim of this laboratory study was to evaluate the marginal sealing ability of four glass-ionomer cements in cervical restorations (Class V) using dye penetration. Two conventional (C-GIC) and two resin-modified (RM-GIC) cements were used either with or without dentin conditioning with polyacrylic acid. MATERIALS AND METHODS: 96 cervical cavities of standardized size were prepared in vitro in the vestibular and lingual portions at the cementoenamel level of 48 premolars. The coronal margins were prepared in enamel, the apical margins were localized in dentin. The 96 cavities were randomly divided into 4 groups of n = 24 each. The cavities of each group were filled with one of the test materials, and only half of the cavities received a dentin conditioning for 20 s with polyacrylic acids before filling. The fillings were finished with a set of abrasive disks 24 h after setting. The restored teeth were stored in saline for 4 weeks and subjected to dye penetration. The depth of dye penetration along the coronal and apical margin was measured on 4 longitudinal sections of each tooth with a semi-automatic image analysis system at 40x magnification. RESULTS: Mean depth of dye penetration ranged from 0 (ChemFil superior without conditioner) to 0.13 mm (ChemFil superior with conditioner) at enamel sites, and from 0.02 (Fuji II LC with conditioner) to 0.74 mm (ChemFil superior with and without conditioner) at dentin sites. CONCLUSION: The conditioning of the cavities before filling improved the marginal adaptation significantly only in the Ketac-Fil group. Conventional glass-ionomer cements (C-GIC) in general demonstrated a lower sealing ability than the light-activated, resin-modified cements (RM-GIC). The adaptation of Photac-Fil quick is best without pretreatment--as recommended by the manufacturer.

Acid Etching, Dental↗
PubMed1999

Crystal structure of the proenzyme domain of plasminogen.

We have solved the X-ray crystal structure of the proenzyme form of the catalytic domain of plasminogen, with the nonessential mutations M585Q, V673M, and M788L, to 2.0 A resolution. The structure presents an inactive protease characterized by Asp740 (chymotrypsinogen 194) hydrogen bonded to His586 (chymotrypsinogen 40), preventing proper formation of the oxyanion hole and S1 specificity pocket. In addition, the catalytic triad residues are misplaced relative to the active conformation adopted by serine proteases in the chymotrypsin family. Finally, a unique form of zymogen inactivation is observed, characterized by a "foot-in-mouth" mechanism in which Trp761 (chymotrypsinogen 215) is folded into the S1 specificity pocket preventing substrate binding.

Amino Acid Sequence↗
PubMed1999

Presence of oxytalan fibers in human regenerated periodontal ligament.

The aim of the present study was to investigate whether oxytalan fibers are formed in the regenerated human periodontal ligament. 6 patients, each of them exhibiting an advanced intrabony defect, were treated with a bioresorbable membrane according to the GTR-principle. Following a healing period of 6 months, the teeth were extracted together with their surrounding soft and hard tissues and subsequently fixed in 10% buffered formalin. Following decalcification in EDTA, the specimens were embedded in paraffin and 8-microm histological sections were cut in the mesio-distal direction, parallel to the long axes of the teeth. The sections were stained with hematoxylin and eosin, or with the oxone-aldehyde-fuchsin-Halmi staining method and examined in the light microscope. A regenerated periodontal ligament containing newly-formed oxytalan fibers was observed in all specimens. Many of them inserted into the newly formed cementum on the root surface. It is concluded that oxytalan fibers are formed de novo in human regenerated periodontal ligament tissue.

Absorbable Implants↗
PubMed1999

Healing of human intrabony defects following treatment with enamel matrix proteins or guided tissue regeneration.

The aim of the present study was to evaluate histologically in humans the healing of advanced intrabony defects following treatment with enamel matrix proteins (EMD) or guided tissue regeneration (GTR). Fourteen patients, each of them displaying 1 advanced intrabony defect around teeth scheduled for extraction were included in the study. The defects were treated randomly either with an enamel matrix protein derivative (Emdogain, BIORA AB, Malmö, Sweden) or with a bioabsorbable membrane (Resolut, Regenerative Material, W.L. Gore & Assoc., Flagstaff, Arizona, USA). At baseline the mean probing pocket depth (PPD) in the EMD group was 11.3 +/- 1.8 mm and the mean clinical attachment level (CAL) 12.1 +/- 2.0 mm, whereas in the GTR group the mean PPD was 11.4 +/- 2.2 mm and the mean CAL 13.3 +/- 2.3 mm. Healing was uneventful in all cases. Neither allergic reactions against EMD or the bioabsorbable membrane, nor suppuration or abscesses were observed. The clinical results revealed at 6 months in the EMD group a mean PPD of 5.6 +/- 1.3 mm and a mean CAL of 9.1 +/- 1.5 mm. In the GTR group the mean PPD was 5.6 +/- 1.3 mm and the mean CAL 10.1 +/- 1.5 mm. The histological analysis showed in the EMD group a mean 2.6 +/- 1.0 mm of new attachment (i.e. new cementum with inserting collagen fibers) and a mean 0.9 +/- 1.0 mm of new bone. In this group, the formation of new attachment was not always followed by bone regeneration. In the GTR group, the mean new attachment was 2.4 +/- 1.0 mm and the mean new bone 2.1 +/- 1.0 mm. In every case treated with GTR, the formation of new attachment was followed by a varying amount of new bone. After both types of regenerative treatment the newly formed cementum displayed a predominantly cellular character. The findings of the present study indicate that the treatment of intrabony defects with enamel matrix proteins or with bioabsorbable membranes enhances the formation of a new connective tissue attachment in humans.

Absorbable Implants↗
PubMed1999

Caries-risk assessment.

Dental caries has a multifactorial aetiology in which there is an interplay of three principal factors: the host (saliva and teeth), the microflora (plaque), and the substrate (diet), and a fourth factor: time. There is no single test that takes into consideration all these factors and can accurately predict an individual's susceptibility to caries. The risk of dental caries can be evaluated by analysing and integrating several causative factors. These include caries experience (initial caries lesions and established caries defects, secondary caries and present caries activity), fluoride use, extent of plaque present, diet, bacterial and salivary activity and social and behavioural factors.

Adolescent↗
PubMed1999

Selective irreversible inactivation of replicating mengovirus by nucleoside analogues: a new form of viral interference.

We describe the selective irreversible inhibition of mengovirus growth in cultured cells by a combination of two pyrrolopyrimidine nucleoside analogues, 5-bromotubercidin (BrTu) and tubercidin (Tu). At a concentration of 5 microgram/ml, BrTu reversibly blocked the synthesis of cellular mRNA and rRNA but did not inhibit either mengovirus RNA synthesis or multiplication. BrTu is a potent inhibitor of adenosine kinase, and low concentrations of BrTu (e.g., 0.5 microgram/ml), which did not by themselves inhibit cell growth, blocked phosphorylation of Tu and thus protected uninfected cells against irreversible cytotoxicity resulting from Tu incorporation into nucleic acids. In contrast, in mengovirus-infected cells, BrTu did not completely inhibit Tu incorporation into mengovirus RNA, allowing the formation of Tu-containing functionally defective polynucleotides that aborted the virus development cycle. This increased incorporation of Tu coupled to mengovirus infection could be attributed either to a reduction in the inhibitory action of BrTu and/or its nucleotide derivatives at the level of nucleoside and nucleotide kinases and/or, perhaps, to an effect upon the nucleoside transport system. The virus life cycle in nucleoside-treated cells progressed to the point of synthesis of negative strands and probably to the production of a few defective new positive strands. Irreversible virus growth arrest was achieved if the nucleoside mixture of BrTu (0.5 to 10 microgram/ml) and Tu (1 to 20 microgram/ml) was added no later than 30 min after virus infection and maintained for periods of 2 to 8 h. The cultures thus "cured" of mengovirus infection could be maintained and transferred for several weeks, during which they neither produced detectable virus nor showed a visible cytopathic effect; however, the infected and cured cells themselves, while metabolically viable, were permanently impaired in RNA synthesis and unable to divide. Although completely resistant to superinfecting picornaviruses, they retained the ability to support the growth of several other viruses (vaccinia virus, reovirus, and vesicular stomatitis virus), showing that cured cells had, in general, retained the metabolic and structural machinery needed for virus production. The resistance of cured cells to superinfection with picornaviruses seemed attributable neither to interferon action nor to destruction or blockade of virus receptors but more likely to the consumption of some host factor(s) involved in the expression of early viral functions during the original infection.

Adenosine↗
PubMed1999

Comparison of enamel matrix proteins and bioabsorbable membranes in the treatment of intrabony periodontal defects. A split-mouth study.

BACKGROUND: Enamel matrix proteins (EMP) have recently been introduced as a new modality for regenerative periodontal treatment. However, limited information is available concerning the comparison of the treatment of intrabony periodontal defects with enamel matrix proteins and other regenerative treatment alternatives. METHODS: The aim of the present controlled clinical trial was to compare the treatment of deep intrabony periodontal defects with EMP to that with guided tissue regeneration (GTR) with bioabsorbable membranes. Sixteen patients, each of whom displayed one pair of intrabony defects located contralaterally in the same jaw, were randomly treated with EMP or with a bioabsorbable membrane. Prior to surgery and 8 months later the following parameters were evaluated by a blinded examiner: Plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). Antibiotics (amoxicillin and metronidazole) were given during the first 10 days after surgery. No statistical significant differences in any of the investigated parameters between the 2 groups were observed at baseline. RESULTS: No serious adverse events (e.g., allergic reactions or abscesses) after any of the treatments were noted during the entire observation period. Membrane exposure occurred in 7 out of the 16 GTR treated sites. Clinical examination was performed again 8 months postoperatively. Sites treated with EMP demonstrated a reduction of PD from 8.1+/-1.7 mm to 4.3+/-1.2 mm (P <0.001) and a change in CAL from 10.3+/-1.8 mm to 7.2+/-1.2 mm (P <0.001). The sites treated with GTR showed a reduction of PD from 8.3+/-1.7 mm to 4.3+/-0.7 mm (P <0.001) and a change of CAL from 10.1+/-1.9 mm to 7.1+/-1.7 mm (P <0.001). Both treatment procedures led to significant improvements of PD and CAL. However, no statistically significant differences in any of the investigated parameters were observed between the test and control group. CONCLUSIONS: It may be concluded that both therapies led to shortterm improvements of the investigated clinical parameters. Further studies of much higher power are needed to support equivalence.

Absorbable Implants↗
PubMed1999

Treatment of intrabony periodontal defects with an enamel matrix protein derivative (Emdogain): a report of 32 cases.

Enamel matrix proteins, including Emdogain, have been proposed as a new modality for regenerative periodontal treatment. However, limited information is available concerning the clinical applicability and therapeutic results with Emdogain. The aim of the present study was therefore to evaluate the clinical outcome following the application of Emdogain in the treatment of intrabony periodontal defects. Twenty-eight patients with marginal periodontitis (thirty-two 2- and 3-walled intrabony defects) were included in this study. The following parameters were evaluated prior to treatment and 8 months after treatment: probing pocket depth, recession of the gingival margin, and clinical attachment level. The postoperative healing phase was uneventful in all cases. There were no complications such as allergic reactions, abscess formation, or infections throughout the entire study period. The mean probing pocket depth was reduced from 8.7 +/- 1.5 mm at baseline to 4.3 +/- 1.6 mm after 8 months (P < 0.001), the mean gingival recession increased from 1.8 +/- 1.2 mm to 3.3 +/- 0.9 mm, and the mean clinical attachment level changed from 10.6 +/- 1.9 mm to 7.6 +/- 1.8 mm (P < 0.001). New hard tissue formation was radiographically observed in 26 of the 32 defects. The present results suggest that the treatment of intrabony periodontal defects with Emdogain may lead to significant improvements of all of the investigated clinical parameters. However, controlled histologic and clinical trials are needed to compare this treatment modality with other conventional and regenerative periodontal surgical methods.

Adult↗
PubMed1999

GTR with bioresorbable membranes in the treatment of intrabony defects: a clinical and histologic study.

The aim of the present study was to evaluate clinically and histologically the treatment of intrabony periodontal defects with a bioresorbable membrane barrier. Fifty-two intrabony periodontal defects were treated according to the principles of guided tissue regeneration (GTR) with a bioresorbable membrane. Results were evaluated by assessing probing pocket depth, recession of the gingival margin, and clinical attachment level at baseline and at 1 and 2 years after therapy. Bone level changes were evaluated radiographically. The postoperative phase was uneventful in all cases. There was a mean probing pocket depth reduction from 8.4 to 3.6 mm, a mean increase of gingival margin recession from 1.5 to 3.0 mm, and a mean clinical attachment level change from 9.9 to 6.5 mm. Mean attachment gain was 3.4 mm. Two teeth scheduled for extraction were also treated with the same bioresorbable membrane. The histologic analysis 6 months after treatment revealed the formation of new connective tissue attachment and new alveolar bone in both cases. Based on the histologic findings it can be concluded that the clinical improvements following GTR with this type of bioresorbable membrane may represent, at least in part, true periodontal regeneration.

Absorbable Implants↗
PubMed1998

A pilot study of confocal laser scanning microscopy for the assessment of undisturbed dental plaque vitality and topography.

Confocal microscopy and vital fluorescence techniques were combined for the first time to investigate ex vivo human dental plaque. The vital fluorescence technique used discriminates vital from dead cells, while confocal laser scanning microscopy allows the optical sectioning of undisturbed biofilms leaving the samples intact during analysis. The concomitant use of both methods made an examination of the three-dimensional architecture of dental plaque possible. The topography of plaque biofilms that were allowed to accumulate in situ on glass and enamel was recorded. The distribution of plaque microflora vitality as well as its accumulation varied according to plaque age. A plaque thickness of up to 8, 35 and 45 microm was estimated ex vivo on enamel after 1, 2 and 3 days, respectively. Young and sparse plaque biofilms consisted mainly of dead material. Vital bacteria were observed on top of this dead layers.

Dental Plaque↗
PubMed1998

Distribution of reducible 4-hydroxynonenal adduct immunoreactivity in Alzheimer disease is associated with APOE genotype.

Two major risk factors for late-onset familial and sporadic Alzheimer disease (AD), a leading cause of dementia worldwide, are increasing age and inheritance of the epsilon4 allele of the apolipoprotein E gene (APOE4). Several isoform-specific effects of apoE have been proposed; however, the mechanisms by which apoE isoforms influence the pathogenesis of AD are unknown. Also associated with AD is increased lipid peroxidation in the regions of the brain most damaged by disease. 4-hydroxynonenal (HNE), the most potent neurotoxic product of lipid peroxidation, is thought to be deleterious to cells through reactions with protein nucleophiles. We tested the hypothesis that accumulation of the most common forms of HNE-protein adducts, borohydride-reducible adducts, is associated with AD and examined whether there was a relationship to APOE. Our results demonstrated that reducible HNE adducts were increased in the hippocampus, entorhinal cortex, and temporal cortex of patients with AD. Furthermore, our data showed that the pattern of reducible HNE adduct accumulation was related to APOE genotype; AD patients homozygous for APOE4 had pyramidal neuron cytoplasmic accumulation of reducible HNE adducts, while AD APOE3 homozygotes had both pyramidal neuron and astrocyte accumulation of reducible HNE adducts. This is in contrast to our previous observations that a distinct HNE protein adduct, the pyrrole adduct, accumulates on neurofibrillary tangles in AD patients. We conclude that APOE genotype influences the cellular distribution of increased reducible HNE adduct accumulation in AD.

Aged↗
PubMed1998

Acro-renal-ocular syndrome: expansion of the phenotype.

We report the sixth described family with acro-renal-ocular syndrome in a boy and more mildy in his mother. Severe upper limb deficiency, dysplastic kidneys, and strabismus are noted in this child in addition to developmental delay, dysplastic corpus callosum, and incomplete myelination. Developmental central nervous system (CNS) malformations have not been described in this syndrome previously and may represent an expansion of the phenotype.

Abnormalities, Multiple↗