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Biomedical subjects

J T Marais

Publications and source records attributed to J T Marais.

At least 19 recordsLinked to original sources
PubMed2002

Biocompatibility of electrochemically activated aqueous solutions: an animal study.

The purpose of the study was to evaluate the biocompatibility of electrochemically activated aqueous solutions on experimental animals. Nine rabbits were subjected to acute eye irritation/corrosion tests, nine rabbits to acute dermal irritation/corrosion and 30 rats to acute oral toxicity (LD50) tests. No significant negative effects were noted. Considering the relatively high levels of exposure of the animals to the solutions and the low levels in the anticipated real clinical situation it is argued that these solutions are indeed biocompatible.

Administration, Cutaneous↗
PubMed2001

Antimicrobial effectiveness of electro-chemically activated water as an endodontic irrigation solution.

AIM: The aim of this in vitro study was to evaluate the antimicrobial effectiveness of electro-chemically activated water (ECA) as an endodontic irrigation solution. METHODOLOGY: The root canals of 60 caries-free, single-rooted, adult, maxillary, anterior human teeth were instrumented and irrigated in a similar method to that used for in vivo root canal treatment. The external root surface of each tooth was sealed, maintaining the access cavities patent and the root canals were inoculated with a suspension containing four bacteria. The teeth were randomly divided into four groups (n = 15). Each group was irrigated ultrasonically with one of the following solutions: distilled water (control), NaOCl (3.5%), and ECA, the latter at pHs 7.0 and 9.0. Antimicrobial effectiveness was established directly after irrigation and again 7 days later, by counting colony-forming units on blood agar plates and by spectrophotometric analysis. RESULTS: Large numbers of bacteria were present in the canals of teeth irrigated with distilled water. No bacteria were observed following irrigation with NaOCl. Neither of the ECA solutions were found to be effective against all the bacteria. Although some reduction in the number of bacteria was evident in the ECA groups, this was not statistically significant (P > 0.05) when compared to sodium hypochlorite. CONCLUSION: Within the confines of this study ECA did not demonstrate antimicrobial effectiveness.

Adult↗
PubMed2000

Cleaning efficacy of a new root canal irrigation solution: a preliminary evaluation.

AIM: A new product, electro-chemically activated water, was compared to NaOCl for its cleaning effect on root canal walls. METHODOLOGY: Root canal treatment was carried out on two groups of extracted teeth with one of the irrigants being used in each group. The control group received no treatment. All teeth were split and the canal walls viewed in a scanning electron microscope. RESULTS: The canal walls of the control group were covered by debris and bacteria. Sodium hypochlorite produced clean surfaces with the dentinal tubules open in some areas and occluded by the smear layer in other areas; in some areas bacteria were visible inside or under the smear layer. Electro-chemically activated water produced markedly cleaner surfaces, removing the smear layer in large areas. CONCLUSIONS: The cleaning efficacy of electro-chemically activated water in root canals was considered to be superior to NaOCl.

Bacteria↗
PubMed1999

Electro-chemically activated water in dental unit water lines.

OBJECTIVE: To investigate the effect of electro-chemically activated water on biofilm contamination in dental unit water lines. DESIGN: Thirteen dental units fitted with independent water systems and used for 12 years with distilled water were divided into two groups, A and B. At the start, one week later, and again four weeks later, the bacterial counts in water from all units were determined. Also specimens of tubing were taken from the units at the beginning and at the end of the study for SEM investigation. In Group A distilled water was replaced with electrochemically activated water (a Russian invention), and used continuously for the duration of the study. In group B, distilled water was used as before, until confirmed to be contaminated. For ethical reasons group B was treated, one week into the study with conventional disinfectants. SETTING: The project was carried out in a clinic of a department of periodontology of a faculty of dentistry during 1998. RESULTS: Both groups showed a marked reduction in bacterial counts. Under SEM Group A showed a total elimination of the biofilm and Group B a partial removal. CONCLUSIONS: Distilled water was ineffective in controlling bacterial counts and biofilm. Electrochemically activated water was effective for this purpose.

Biofilms↗
PubMed1999

The effect of post-curing on Vickers Hardness of four light-cure resin composite materials.

The use of post-curing ovens to post-cure light-cured resin composite restorations leads to a decrease in the negative effects of polymerization shrinkage and an increase in the hardness and wear resistance of the material. The aim of this study was to compare the Vickers Hardness (VH) of four different light-cure resin composite materials. In one group, samples of the four materials, Z100, Tetric Ceram, F2000 and Heliomolar were light-cured only, and in the other group a similar set of samples were light-cured and also post-cured in a DI 500 post-curing oven. VH vests were then carried out on the samples. All samples in the post-cured group had higher VH values (p = 0.000) than the corresponding samples in the light-cured only group. Z100 and F2000 had, in both groups, significantly higher VH values (p = 0.000) than Tetric Ceram and Heliomolar.

Acrylic Resins↗
PubMed1998

Failure of apicoectomy surgery and successful endodontic retreatment.

The optimal way to address endodontic failures is to retreat the root canal system first and only then to consider apical surgery. Unfortunately, in practice, it is often not done in this way. Patients are subjected to apical surgery, without any attempts at retreatment. A series of cases is presented illustrating failures of apicoectomy and successful endodontic retreatment.

Apicoectomy↗
PubMed1998

Restoring palatal tooth loss with composite resin, aided by increased vertical height.

Loss of palatal enamel and dentine of maxillary anterior teeth often leads to fractures of incisal edges. This phenomenon has always presented dentists with a demanding challenge. An ultraconservative approach using composite resin onlays together with an increase in vertical height is presented. Three cases illustrating the technique are reported.

Adult↗
PubMed1998

A successful combination of conflicting approaches to diastema closure--a case report.

The closure of anterior maxillary diastemas can be accomplished in several ways. A case is reported where treatment initially consisted of the provision of porcelain laminate veneer restorations, with an unsatisfactory result. Subsequently, the restorations were reduced drastically in width and reshaped. The tooth widths were calculated from tables of mean measurements. The spaces were closed by orthodontic treatment and the original restorations were retained, saving the patient considerable treatment.

Adult↗
PubMed1997

The effect of bleaching agent on composite/enamel bonding.

This in vitro study evaluates the effect of an in-office light-activated hydrogen peroxide bleaching agent on the shear bond strength of composite resin to etched enamel. Specimens were divided into 4 groups. Group 1 specimens were not bleached and served as the control; Group 2 consisted of specimens bonded immediately after bleaching; Groups 3 and 4 of specimens bonded 1 and 2 weeks respectively after bleaching. The mean shear bond strengths (MPa) of Groups 2 (14.2 +/- 4.9), 3(19.2 +/- 3.2) and 4 (23.1 +/- 3.7) were lower than the value obtained in Group 1 (25.1 +/- 3.7). Groups 2 and 3 had significantly lower shear bond strengths than the unbleached Group 1 (25.1 +/- 3.7). It is suggested that bonding procedures be postponed for two weeks after any bleaching procedure had been done.

Composite Resins↗
PubMed1997

[The effect of bonded and nonbonded posts on the fracture resistance of dentin].

This in vitro study determined the effect of bonded and non-bonded cast, serrated, tin plated, parallel gold posts on the fracture resistance of surrounding dentine walls. Specimens were divided into two groups. One group's posts were luted with zinc phosphate cement and the other group's posts were tin-plated and adhesively bonded with an adhesive resin cement. Three different dentine wall thicknesses, namely 0.5 mm, 0.75 mm and 1.0 mm were prepared, subdividing the specimens of each main group into three subgroups. Specimens were subjected to a 50 degrees oblique force. The force required to fracture the dentinal walls was registered. There was no statistically significant differences in the fracture resistance of dentine with the two different cements or of the different dentine wall thicknesses.

Dental Bonding↗