Quintessence International, 05/1997

A new restorative method, (the Edge Up technique) enables the correction of defects in the anterior tooth area with a maximum preservation of tooth substance. The basis of this technique is a special preparation method (a circular extended shoulder preparation in the enamel or an angle prepar ation) and a preparation kit matched to the peculiarities of this preparation technique.

The present classification used by the profession for the identification of carious lesions was devised by Black about 100 years ago. It was based, in part, on the location of the lesion but was modified to take into account the materials that were available for restoration. Over the last 20 years, there has been considerable modification of these materials; adhesion between the restorat ion and tooth structure is now possible, and the understanding of the relevance of fluoride and other ions in the prevention and repair of caries has improved. It would be logical at this time to adopt a new classification based on the site of the carious lesion and the extent to which it has progressed. More relevant detail could be recorded for each restoration, and this would be of value both for personal records and epidemiologic studies. The proposal is a simple digital system that is compatible with the use of computers for record keeping.

Tooth wear is an ever-increasing problem, and younger patients are particularly at risk. The problem is likely to continue as patients' demands and expectastions rise and as more natural teeth are retained into old age. The etiology of tooth wear is reviewed, with emphasis on those factors that appear to be major contributors to the problem at the moment. The clinical appearance of tooth wear is also discussed. It would appear taht erosive factors are a significant cause of tooth wear. The prominence of acidic damage of tooth tissue is probably a reflection of society's concern with healthy eating and appearance.

The purposes of the present study were to examine the frequency of cervical enamel projection in mandibular molars w ith class II furcation defects and to examine the response of these teeth to guided tissue regeneration procedures. Probing depth and vertical and horizontal peridodontal attachment levels were recorded with a constant-force electronic periodontal probe. Following surgical exposure of the bifurcation and prior to membrane placement, the cervical enamel projection was examined and then graded clinically; photographs were taken to allow further examination of the bifurcation. An overall improvement in clinical parameters was observed in most sites. Cervical enamel projection was present in 82.1% of all molars examined. Grade II was the most prevalent (34.8%). Patients with any degree of cervical enamel projection demonstrated significantly higher mean probing depths at baseline than did patients without cervical enamel projection. Likewise, pretreatment probing attachment levels were higher in patients with soem degree of cervical enamel projection. However, greater posttreatment horizontal and vertical attachment gains were observed in sites with a baseline cervical enamel projection.

A retrospective study examined the frequency of a feasible or remotely possible indication for regenerative therapy of furcation involvement in a large group of periodontally diseased patients. The judgment about the feasibility of the indication was mainly based on results of current randomized controlled clinical trials with regard to tooth type and location of the furcation lesion. Data from 558 patients treated by two periodontists, one experienced and one in training, were analyzed. Furcation involvement of at least one multirooted tooth was found in 40% and 63% of the two dentists' patients. In only 20% and 27% of their patients was there a potential indication for regenerative furcation treatment. Of 1,134 furcation lesions, 180 (15.9%) were conceivably suitable for this procedure. Only 17 sites with a feasible or remotely possible indication were treated in that way. In most cases, conventional furcational treatment (flap surgery with scaling and root planing) was performed.

The effectiveness of a mouthwash based on triclosan in combatting plaque and gingivitis was compared with a mouthwash based on nonsaponifiable maize germ (Zea mays L). Both were used to supplement conventional mechanical oral hygiene. The study was carried out under double-blind conditions with a negative control (a placebo) and a positive control (a mouthwash based on chlorhexidine). After a period of 14 days to allow the Plaque Index and Gingival Index to standardize, the 43 subjects who formed the sample were examined weekly for 3 weeks. During the study, five subjects were excluded because they did not meet criteria for selection for the study. Although the mouthwash based on triclosan reduced the Plaque Index by 7.3% in comparison with the placebo negative control (a less marked effect than that of chlorhexidine, which achieved an 8.43% reduction), it had scarcely any effect on th e Gingival Index. The mouthwash based on Zea mays L had no beneficial action on the Plaque Index, which increased slightly, but it led to an improvement in the Gingival Index (7.17% in comparison with the placebo).

A 4-year-old boy who suffered avulsion of a primary maxillary central incisor was treated with an all-porcelain, resin-bonded retainer. Although prosthetic replacement of primary teeth with resin-bonded prostheses is not common, the method may be beneficial in certain cases

Thirty-six extracted, noncarious, nonfractured human incisors were divided into four groups of nine teeth. Endodontic access cavities were prepared, the pulp chamber was debrided, the root canals were cleansed, and root canal treatment was completed. Pulp cavities of teeth in group 1 received a cotton pellet and were sealed with Cavit. Groups 2, 3, and 4 received a mixture of 30% hydrogen peroxide and sodium perborate for 3, 4, and 7 days, respectively, were sealed with Cavit, and were stored in a humidor until used. Cavit and the other materials were removed, and the cavities were rinsed and restored with Scotchbond Multipurpose and Silux. The teeth were thermocycled, stained with 50% silver nitrate, and sectioned longitudinally. Dye penetration was measured. Results indicated that bleaching adversely affected the marginal seal at the tooth-restoration interface, as evidenced by increased microleakage; the highest rate of microleakage was found after the 7-day application of bleaching materials.

The objective of this study was to evaluate the influence of several factors on the hardness of resin-modified glass-ionomer cements (hybrid ionomers) and polyacid-modified resin composites (compomers). Disk-shaped specimens were prepared from the following materials: Vitremer, Fuji II LC, Photac-Fil, and Dyract. Three specimens of each product were irradiated with a light-curing device and three were not. Barcoll hardness was determined on both sides of the specimen 10 minutes after irradiation and after 48 hours of immersion in 37 degrees C water. A factorial design was used to evaluate the factors that influenced the results. The Dyract group that was not light cured was not included in the analysis beca use the product did not harden under this circumstance. Analysis of variance revealed a significant effect of material, time, and specimen side when light curing was carried out. The use or nonuse of light curing was also significant. For some hybrid ionomers (eg, Photac-Fil), light curing is a more essential step than for others to obtain adequate hardness values.

Three-dimension (proton) magentic resonance microimages of a number of extracted teeth (both healthy and carious) were obtained using a Bruker AM300WB magnetic resonance spectr ometer fitted with a Bruker microimaging attachment. Full data sets have been acquired as 90-um to the third power voxels to enable high-quality full-surface (external and internal) reconstructions to be computed. Possession of such data has allowed mapping of the complete range of intensities in any selected image slice. The application of artificial color was found to aid the interpretation of both image types. All teeth showed the expected dental morphologies. The carious regions of the diseased teeth gave an intense image that was readily distinguishable from the other soft tissue.