A clinical study of root surface conditioning with an EDTA gel. I. Nonsurgical periodontal treatment.

The present study was undertaken to investigate if subgingival administration of an EDTA gel has any adjunctive effect to subgingival and supragingival root debridement. The investigation was performed in one study center involving 6 clinical investigators and 91 patients. The patients were selected from 2 patient populations: 41 were included from a consecutive referral material on a voluntary basis, and 50 were included from a maintenance care material at the clinic. No significant differences were found between the EDTA-treated and control groups with respect to clinical attachment gain or probing pocket depth reduction. The referral patients showed a significant improvement of pocket depth and attachment gain compared to maintenance care patients at the clinic. In multiple regression analyses, it was found that patients with small attachment losses at baseline responded better to treatment than patients with severe periodontitis. Also, in multivariate analyses, referral patients responded better than maintenance patients when controlling for other predictors.

A clinical study of root surface conditioning with an EDTA gel. II. Surgical periodontal treatment.

The objective of the present trial was to assess the effect of an EDTA gel applied during surgical periodontal therapy on probing depth reduction and periodontal attachment gain, allowing for the influence on healing of smoking as well as postsurgical oral hygiene. For comparison, citric acid treatment and control surgery only were included. The investigation was performed in one study center involving one clinical investigator and 68 patients. The patients were selected from a consecutive referral material on a voluntary basis. No statistically significant differences between treatment groups concerning attachment gain or pocket depth reduction could be seen after 3 and 6 months. A subgroup of the sample--21 patients who scored zero on the bleeding index at 3 and 6 months postsurgery and did not smoke--had a borderline significantly higher attachment gain in response to experimental treatment as well as a significant pocket depth reduction 6 months postsurgery when controlling for age, gender, Plaque Index at baseline, and treatment in multiple regression analyses. However, this was true not only for EDTA treatment but for citric acid and control treatment as well.

Effect of a chemo-mechanical caries removal system (Carisolv) on dentin topography of non-carious dentin.

The purpose of the present study was to examine the morphology of healthy dentin surfaces after treatment with Carisolv followed by conditioning with phosphoric acid and EDTA, since surface morphology may be of interest for dentin bonding. Another purpose was to evaluate the effect of treatment with Carisolv on healthy non-carious dentin surfaces with exposed collagen fibers. Scanning electron microscopy was utilized to carry out a detailed morphological examination of the dentin surfaces with regard to presence or absence of both smear layer and collagen fibers. Twelve premolars extracted for orthodontic reasons from young adults were used. The two etchants appeared to have produced two distinctly different surfaces. Etching with phosphoric acid following Carisolv treatment resulted in a porous dentin surface, while EDTA etching without prior Carisolv treatment appeared to have uncovered an intact collagen network. In contrast, the surfaces treated with Carisolv prior to EDTA etching displayed smooth intertubular surfaces with only occasional fibers. Apparently, the ability of EDTA to expose collagen in the dentin surface is counteracted or inhibited by the Carisolv treatment. Furthermore, it cannot be excluded that the Carisolv treatment in itself may have dissolved collagen fibers. Since most bonding systems claim bonding to the collagenous component of dentin, the question arises which of the etched surfaces is preferable and to what degree the collagenous component contributes to bonding strength. Further studies are thus needed to evaluate the micromechanical retention of a restoration to the different surfaces described in the present study.

Smear layer formed by different root planing modalities and its removal by an ethylenediaminetetraacetic acid gel preparation.

The purpose of the present study was (1) to examine smear layer formation following different root planing modalities, and (2) to evaluate its removal and the exposure of collagen using an ethylenediaminetetraacetic acid gel preparation. Twenty-four periodontitis-affected human teeth were mechanically root planed. Twelve teeth were etched with an ethylenediaminetetraacetic acid gel preparation. The surfaces were examined by a scanning electron microscope. The results showed that root planing resulted in a smear layer covering the root surfaces, irrespective of treatment modality. The smear layer could be efficiently removed with the ethylenediaminetetraacetic acid gel preparation. During this process, collagen fibers were exposed to varying degrees.

Ultrasonic subgingival root planing and EDTA etching in a one-step procedure.

The purpose of the present study was to investigate if ultrasonic debridement and EDTA etching could be combined in a ore-step procedure. Tap water was exchanged for a 24% EDTA solution as irrigation agent during root planing with a piezo scaler. 24 human teeth extracted due to severe periodontal disease were used and the results were evaluated with scanning electron microscopy. Results indicate that synergistic effects (smear removal and exposure of collagen fibers) were negligible with conventional application of the irrigation fluid to the working area of the scaling tip while a marked effect was evident when the EDTA solution was applied directly to the working area of the piezoelectric scaler through a customized tip.

Two point mutations convert a catalytically inactive carbonic anhydrase-related protein (CARP) to an active enzyme.

A murine carbonic anhydrase-related protein (CARP) has been expressed in Escherichia coli and purified to near homogeneity. The polypeptide chain consists of 290 amino acid residues and has a calculated molecular mass of 32,950 Da. By introducing two mutations, Arg117 --> His and Glu115 --> Gln, we created a metal-binding center homologous to that in the carbonic anhydrases from the animal kingdom. In contrast to unmodified CARP, this double mutant was isolated as a 1:1 zinc-protein complex. While unmodified CARP is catalytically inactive, the mutant catalyzes CO2 hydration with a significantly higher efficiency than the mammalian low-activity carbonic anhydrase isozyme III. The activity is strongly inhibited by the powerful and selective carbonic anhydrase inhibitor, acetazolamide.