A new concept for etching in restorative dentistry?

The purpose of the present study was to investigate the scanning electron microscopic texture of enamel and dentin cavity surfaces in extracted human teeth following different etching modalities, specifically combinations of etchants adapted to the tissue composition of the cavity walls. It was concluded that an etching technique that combined the action of 2 different etchants--ethylenediaminetetraacetic acid (EDTA) on dentin and phosphoric acid on enamel--optimized retention structures on each tissue surface of a dental cavity better than either 1 of the 2 etchants that were applied to both types of tissue in the cavity walls.

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.

Smear removal and collagen exposure after non-surgical root planing followed by etching with an EDTA gel preparation.

Low pH aqueous solutions of citric acid have been used in surgical periodontal therapy mainly for two reasons. It dissolves smear after a relatively short exposure time and it has been claimed to selectively remove root surface-associated mineral exposing collagen to varying degrees. The use of low pH etching agents has recently been challenged in both experimental in vitro and in vivo studies based on their necrotizing effect on the surrounding periodontal tissues. The purpose of the present study was to assess the efficacy of subgingival application of an EDTA gel preparation in removing smear and exposing collagen fibers in root surfaces following non-surgical periodontal therapy. Root surfaces which were root planed did not reveal any patent dentinal tubuli or collagen fibers. This was in contrast to the findings seen after root planing followed by etching, where intertubular surfaces were covered by a dense fibrillar network extending into patent dentinal tubuli. In high magnification these intertubular fibers displayed the cross-striated texture typical for collagen fibers. Etching of root planed surfaces with EDTA may thus enhance the effect of non-surgical root debridement in the same way as has been shown during experimental surgical procedures.

Periodontal healing in relation to radiographic attachment and endodontic infection.

The aim of the present study was primarily to investigate if periodontal healing assessed by reduction in probing depth over time is significantly influenced by the initial degree of horizontal radiographic attachment loss and secondly to what degree any such relationship influenced the already established correlation between presence of a root canal infection and impaired marginal healing. The investigation was conducted as a retrospective study on 160 patients referred to a specialist periodontal clinic. The choice of variables was guided by an assumption that each variable either positively or negatively contributed to determine probing depth reduction. It was found that healing after scaling and root planing over time was significantly impaired with more advanced loss of radiographic attachment. Regardless of the extent of radiographic attachment loss, healing after scaling and root planing was also significantly impaired over time by the presence of a root canal infection.

Radiographic attachment in periodontitis-prone teeth with endodontic infection.

The purpose of the present investigation was to examine the influence of a root canal infection on radiographic attachment. In addition, influence of the quality of the root fillings as well as the size of the periapical radiolucencies were studied. The investigation was conducted as a retrospective study on a consecutive referral population. The periapical conditions in endodontically-involved single-rooted teeth from a selected patient sample were correlated to the periodontal status of the teeth. Teeth with periapical lesions were found to have lost significantly more radiographic attachment, approximately 2 mm. A comparison between pocket depth in teeth with and without periapical pathology consistently showed that periapical pathology was significantly correlated to an increased pocket depth, also after adjusting for differences in radiographic attachment. It was concluded that periodontitis-prone teeth run a significantly higher risk of losing periodontal attachment if a root canal infection is also present and evident as a periapical radiolucency.