Biomedical subjects

Matthias Zehnder

Publications and source records attributed to Matthias Zehnder.

23 records · Page 2Linked to original sources

PubMed2003

Tissue-dissolution capacity and dentin-disinfecting potential of calcium hydroxide mixed with irrigating solutions.

OBJECTIVE: The goal of this study was to compare the tissue-dissolution potential and antibacterial effectiveness of a conventional Ca(OH)(2)/saline paste with equivalent Ca(OH)(2)/NaOCl and Ca(OH)(2)/chlorhexidine digluconate medications. STUDY DESIGN: Tissue specimens were obtained from freshly dissected pig palates. Tissue pieces of similar form and weight were incubated in air-tight containers with Ca(OH)(2) pastes or solutions proper for up to 7 days. Antimicrobial testing was performed in dentin blocks infected with Enterococcus faecalis. Medicated, sealed dentin specimens were incubated for 1 and 5 days, and bacterial growth was tested at different dentin depths. RESULTS: Up to day 4, the Ca(OH)(2)/irrigating solution mixtures dissolved tissue more effectively than the conventional Ca(OH)(2)/saline paste. After 7 days, however, no statistically significant differences were found between the saline and hypochlorite mixtures, but the Ca(OH)(2)/chlorhexidine medication was significantly less effective. Dentin block disinfection was quicker and more thorough with the Ca(OH)(2)/chlorhexidine or the Ca(OH)(2)/NaOCl than with the Ca(OH)(2)/saline paste. CONCLUSION: Ca(OH)(2)/irrigant mixtures under investigation appear more advantageous than the conventional Ca(OH)(2)/saline mixture, and merit further investigation in a clinical study.

Analysis of Variance↗

PubMed2003

[Irrigants and intracanal medicaments in endodontics].

Modern, biologic root canal therapy should be performed with suitable irrigating solutions and intracanal medicaments. The goal of endodontic treatment is to free the treated tooth from infection and prevent reinfection as thoroughly as possible by means which do not put the organism at risk. In this review of the literature, an evidence-based concept for irrigation and medication of root canal systems is presented. Irrigants and medicaments are discussed with respect to their antimicrobial, tissue-dissolving and endotoxin-decontaminating capacity in relation to their systemic toxicity. Recent findings pertaining to interactions of root canal medicaments and irrigating solutions and their impact on a sound irrigating and medicating concept are discussed.

Anti-Infective Agents, Local↗

PubMed2002

Matrix metalloproteinase levels and gelatinolytic activity in clinically healthy and inflamed human dental pulps.

The role of matrix metalloproteinases (MMPs) in the breakdown of pulp tissue of teeth with severe caries has not yet been directly elucidated. This study was to determine the levels of selected MMPs and the overall gelatinolytic activity in clinically healthy and inflamed human dental pulps of 29 healthy subjects, aged 10-19 yr. Seventeen pulps were collected from subjects diagnosed with symptomatic pulpitis, and 18 control pulps were obtained from 12 subjects following premolar extraction for orthodontic reasons. The levels of MMP-1, MMP-2, MMP-3 and MMP-9 were determined with enzyme-linked immunosorbent assay. Densitometric analysis of gelatin zymograms was used to assay gelatinolytic activity in pulp supernatants. The MMP-1 levels were below the detection limit for both groups. Levels of MMP-2 and MMP-3 were significantly lower in symptomatic vs. clinically healthy pulps. In contrast, levels of MMP-9 in inflamed pulps were significantly higher than those recorded in clinically normal pulps. The overall gelatinolytic activity was elevated in inflamed pulps compared with healthy counterparts. Further, the gelatinolytic activity was positively correlated with MMP-9 levels. The data obtained suggest a key role of MMP-9 in the breakdown of inflamed human dental pulp tissue.

Adolescent↗

PubMed2002

Tissue-dissolving capacity and antibacterial effect of buffered and unbuffered hypochlorite solutions.

OBJECTIVE: The goal of this study was to compare the dissolving potential of Dakin's solution with that of equivalent buffered and unbuffered sodium hypochlorite solutions on fresh and decayed tissues. In addition, the antimicrobial effect of Dakin's solution and equivalent unbuffered hypochlorite was tested. STUDY DESIGN: Tissue specimens were obtained from freshly dissected pig palates. Unbuffered 2.5% and 0.5% sodium hypochlorite solutions and 0.5% solutions buffered at a pH of 12 and a pH of 9 (Dakin's solution) were tested on fresh and decayed tissue. Tissue decay was assessed histologically. Antimicrobial testing was performed with Enterococcus faecalis in dentin blocks and on filter papers. RESULTS: The 2.5% NaOCl solution was substantially more effective than the three 0.5% solutions in dissolving the test tissues. Buffering had little effect on tissue dissolution, and Dakin's solution was equally effective on decayed and fresh tissues. No differences were recorded for the antibacterial properties of Dakin's solution and an equivalent unbuffered hypochlorite solution. CONCLUSIONS: In contrast to earlier statements, the results of this study do not demonstrate any benefit from buffering sodium hypochlorite with sodium bicarbonate according to Dakin's method. An irrigation solution with less dissolving potential may be obtained by simply diluting stock solutions of NaOCl with water.

Analysis of Variance↗

PubMedDate not supplied

Wear resistance and surface roughness of a newly devised adhesive patch for sealing smooth enamel surfaces.

A laboratory study assessed the wear resistance and surface roughness after chemical and mechanical wear of a newly devised adhesive patch when used as a smooth surface sealant. Forty-eight enamel discs were prepared from bovine lower central incisors. Sixteen specimens were treated with one of two sealing options: the prototype of an adhesive patch or a flowable resin. Unsealed enamel served as the positive control. Wear and surface roughness was measured at baseline and after all the samples were immersed in saliva or lactic acid (n=8 per treatment group) for up to 21 days, during which the experimental and control enamel surfaces were exposed to 10 double-stroke toothbrush cycles per day. In saliva and lactic acid, the sealed specimens showed no significant wear during the observation period (p=0.1841). Only untreated specimens exposed to lactic acid showed a significant substance loss after 14 and 21 days (p=0.0186). The patch and flowable resin showed no differences in surface roughness values at respective times (p=0.385); whereas the surface roughness of the unsealed specimens in lactic acid was significantly higher (p<0.0001). It was concluded that the adhesive patch under investigation merits further study to assess its potential as a sealant for smooth enamel surfaces.

Adhesives↗