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Biomedical subjects

G Makris

Publications and source records attributed to G Makris.

At least 19 recordsLinked to original sources
PubMed2005

A clinical study of plasminogen activator activity in gingival tissue in dogs with gingivitis and periodontitis.

The aim of the present study was to evaluate plasminogen activator activity (PAA), tissue-type plasminogen activator (t-PA) antigen level and plasminogen activator inhibitor-1 (PAI-1) antigen in normal canine gingival tissue samples, gingivitis as well as in different stages of periodontal disease. Gingival tissue from 141 adult dogs were analysed spectrophotometrically in order to determine PAA. The tissues were also examined histopathologically. The Sulcus Bleeding Index was used to evaluate the active and inactive phase of periodontal disease. T-PA antigen as well as PAI-1 antigen level was measured by ELISA. There was a significant increase of PAA and t-PA antigen in samples from inflamed gingival tissue compared with normal gingival tissue, while PAI-1 antigen was not detected in either normal or inflamed gingiva. As the severity of periodontal disease was increasing, PAA and t-PA antigen values were significantly higher in periodontitis tissue sample groups, according to the pattern: gingivitis moderate bleeding>slight bleeding, P<0.001). In conclusion, this study indicates that PAA and t-PA antigen level may be used to evaluate the evolution of periodontal disease in dog.

Animals↗
PubMed2000

Caries prevalence in 6-, 11- and 14-year-old children in the Cyclades Islands, Greece.

Following the World Health Organization criteria, a total of 1,604 out of 3,225 children aged 6, 11 and 14 years living on the 20 islands of the Cyclades complex were examined. Recordings showed that in the 6-year-old children, the mean dmft index was 2.21 (SD=3.00) with 46% caries free. In the 11-year-old children, the DMFT averaged 1.39 (SD=1.78) with 46% caries free. In the 14-year-old children, the mean DMFT was 2.62 (SD=2.83) with 32% caries free. Statistically significant differences were found in the DMFT of the 11- and 14-year-old subjects living in naturally water fluoridated and non-fluoridated areas. According to these data, it appears that the first two WHO targets for the year 2000 are almost fulfilled.

Adolescent↗
PubMed1995

Titanium nitride ceramic film against polyethylene. A 48 million cycle wear test.

Wear is a major late complication of total joint arthroplasty, particularly for younger, active patients. Many patients could produce > 40 million motion cycles after joint replacement. Based on current experience and testing, typical joint prostheses are likely to wear out, and need revision in such patients. One problem is degradation of the metal (counterface) surface. A harder, more abrasion resistant, counterface surface is needed. This study evaluated the long-term wear of the titanium nitride ceramic film against ultra high molecular weight polyethylene. In this test, 4 47-mm femoral cups with a polished 8-micron-thick titanium nitride coating were run against 4-mm-thick metal-backed polyethylene bearings machined from GUR415 extruded rod in water at 37 degrees C at 5 Hz and a 2200-N fluctuating load. Wear of the counterface and bearing were extremely low. The average maximum reduction in thickness of the polyethylene was < 0.02 mm, and < 2 microns in the ceramic film. The average polyethylene wear rate was only approximately 2% of that found in a similar test using 32-mm cobalt chromium femoral heads. The titanium nitride-polyethylene couple has great potential as a lifetime bearing combination.

Alloys↗
PubMed1994

Estimating the level of knowledge of Greek students on cancer aetiology and ways of prevention.

The aim of the present research was to establish the perception of the relative importance of various environmental risk factors for cancer among Greek students. A questionnaire was used to assess the students' knowledge on cancer causation. The factors examined included smoking habits, drinking, geophysical factors, pollution, dietary factors, and the students' awareness of the contribution of these factors to the generation of the disease. In addition, we examined the students' attitude to the factors as cancer risk determinants. A random sample of 1,136 students was selected from the matriculated students of various departments of the Aristotelian University of Thessaloniki. We found a relative important lack of knowledge on subjects related to the generation of the disease.

Adolescent↗
PubMed1991

Evaluation of contact stress in metal-backed patellar replacements. A predictor of survivorship.

Significant wear-through and dissociation failures of metal-backed, point and line contact patellar replacements are associated with excessive contact stresses on the polyethylene-bearing surfaces. Analytical mathematical contact-stress analysis was used to evaluate various patellar component geometries under loading conditions consistent with walking, stair descent, and deep knee bends, respectively. Typical point- and line-contact patellar-surface geometries exceeded the manufacturer's recommended maximum permissible compressive stress level of 10 MPa by a factor greater than three, which also exceeds the yield stress of ultra-high, molecular-weight polyethylene. A metal-backed, rotating-bearing, area contact geometry patellar replacement maintained safe contact stress levels at less than half of the maximum permissible compressive stress level. These contact stress analyses predict early fatigue failure of all-polyethylene or metal-backed, point- and line-contact patellar replacements, while predicting long-term survival of area-contact, rotating-patellar replacements. Clinical evaluation of these various implants support the conclusions of these analyses. Contact stress analysis should precede any clinical use of patellar implants to avoid predictable failure mechanisms.

Biomechanical Phenomena↗
PubMed1990

[Adhesive cast restorations].

The aim of this article is to present the clinical use of the adhesive cast restoration in the treatment of the advanced perio case in an effort to overcome the serious restorative problems related to those cases. The use of the adhesive cast restoration in the advanced periodontal conditions has proved that it can be considered a permanent restoration. The main advantages in the use of the adhesive cast restoration are: i) Minimal tooth preparation, which eliminates the possibility of pulpal contamination. In fact, pulpal integrity is of crucial importance in the advanced perio case because of the close interrelationship between the pulp tissue and periodontal structures. ii) Supragingival lingual margins, which do not compromise the patient's esthetics and permit for good plaque control. iii) Reversibility of the restoration. iv) Reduced cost, which helps the clinician to use teeth with guarded prognosis from a periodontal point of view.

Costs and Cost Analysis↗
PubMed1982

Amoxicillin and clavulanic acid combination: clinical and laboratory evaluation in pulmonary infections.

Twenty-four patients with pulmonary infections (7 pneumoniae, 17 exacerbations of chronic bronchitis) were treated with a combination of 250 mg of amoxicillin and 125 mg of clavulanic acid supplemented by 500 mg of amoxicillin every eight hours. All patients showed good clinical, roentgenological, and bacteriological response. Bacteria were cleared from sputum by the third day of treatment in half of the patients and by the end of treatment in all but one of the others. Pathogens eradicated from sputum, with concurrent clinical cure, included gram-negative bacteria producing cephalosporinases shown to be resistant to the combination drug by both disk and minimal inhibitory concentration determinations.

Adult↗
PubMed1979

[Changes in the endosteal bone balance in periodontal disease induced in golden hamsters].

The purpose of this study was to analyze through morphometric analysis, the variations of the endosteal bone balance during experimental periodontal disease induced in the golden hamster. The results showed that the osteoclastic resorption is increased by a factor of 5 (p less than 0.01) and the bone formation reduced by about 50% (p less than 0.01). The bone volume decreased slightly (by 6%) but significantly (p less than 0.01). No correlation between respectively resorption and formation and bone volume was found.

Alveolar Process↗
PubMedDate not supplied

[In vitro effect of an air-powder abrasive system on the susceptibility of dental tissues to artificial caries].

An air-powder jet abrasive system has recently been introduced for stain removal from teeth. The purpose of this study was to investigate whether its abrasive effect on enamel and on the root renders these surfaces more caries prone. The AIR-FLOW (EMS SA) abrasive was directed for 30 seconds on predetermined (test) sites of the crown and the root of each of 10 teeth, under controlled conditions. These and adjacent (control) sites in the form of windows, were then exposed to an acid gel for caries-like lesion formation. The central sections of each window were examined under the polarizing microscope. The enamel treated with the abrasive appeared somewhat roughened while the root showed crater-like abrasion defects averaging 303 mm (+/- 140) in depth. The mean depth of enamel test lesions was 253 mm (+/- 77) and that of control lesions 98 mm (+/- 77), the difference being statistically significant (p less than 0.001). The corresponding values for the root lesions were 695 mm (+/- 103) and 695 mm (+/- 120) respectively. Consequently, enamel surface modification by AIR-FLOW decreased the resistance of enamel to caries-like lesions in vitro and it is postulated that this may also happen at "susceptible sites" in vivo. Loss of cementum and superficial dentine abraded by AIR-FLOW was significant but did not lead to increased root susceptibility to caries-like lesions in vitro.

Air↗