The operative management of primary and secondary caries assumes that all discoloured tissue at the enamel-dentine junction (EDJ) represents active disease and this is removed to arrest the carious process. This study aims to establish clinical criteria to differentiate between active and arrested caries at the EDJ using microbiological assessment of dentine samples to verify its clinical status. Radiographs were available for posterior teeth. Cavities (n = 205) were prepared under rubber dam. After gaining access, areas of the EDJ were chosen and assessments made of consistency (soft, medium, hard), colour (dark brown, mid-brown, pale) and moisture content (wet, dry). Dentine was removed by using a No. 3 round burr and placed in 1 ml of bacteriological culture broth. This sampling procedure was repeated at the same site once during cavity preparation and again when the cavity was judged as fully prepared. Samples were vortexed, diluted and cultured to give viable counts of the total anaerobic micro flora, mutans streptococci and lactobacilli; viable counts were expressed as log₁₀ (CFU per sample +1). Results showed no significant differences between the microflora of primary and secondary caries . The number of bacteria recovered diminished significantly as cavities were completed. Initial samples from soft and wet lesions harboured significantly more bacteria, lactobacilli and mutans streptococci than samples from medium, hard or dry lesions. Lesions visible on radiographs harboured more bacteria, including lactobacilli and mutans streptococci, while dentine colour was not discriminatory. In conclusion, the relevant clinical criteria for the diagnosis of infected dentine at the EDJ were visibility on radiographs, soft lesions and wet lesions.

Caries at the margins of restorations is difficult to diagnose. In particular, the relevance of both marginal ditching and staining around amalgam restorations is unclear. This clinical study questions the relevance of marginal ditching and color change to the level of infection of the dentin beneath the margins of amalgam restorations. Clinically visible sites (330) on the tooth/restoration margin were selected on 175 teeth. The enamel adjacent to each site was noted as stained (a grey discoloration) or stain-free. One hundred and seventy-eight sites were clinically intact, 83 sites had narrow ditches (< 0.4 mm), and at 49 sites, wide ditches were present (> 0.4 mm). Twenty sites with frankly carious lesions were also included. Plaque was sampled at the tooth-restoration margin, and the dentin was sampled at the enamel-dentin junction below each site. Samples were vortexed, diluted, and cultured for total anaerobic counts, mutans streptococci, lactobacilli, and yeasts. Plaque samples showed that margins with wide ditches (> 0.4 mm) harbored significantly more bacteria, mutans streptococci, and lactobacilli than did clinically intact margins and margins with narrow ditches. There were no significant differences in the degree of infection of the dentin beneath clinically intact restorations and those with narrow ditches, but samples associated with wide ditches and carious lesions yielded significantly more bacteria, mutans streptococci, and lactobacilli. The color of the enamel adjacent to the sample site was irrelevant to the level of infection of the dentin beneath the filling margin, provided a frankly carious lesion was not present.(ABSTRACT TRUNCATED AT 250 WORDS)

Azithromycin may be a useful adjunct in the treatment of adult periodontitis, particularly where deep pockets are present.

During cavity preparation conventional tactile and optical criteria are used to assess the caries status of the enamel-dentine junction, cavity preparation being considered complete when this area is hard to a sharp probe and stain free. In the present study 201 cavities were prepared under rubber dam. When caries removal was considered complete using the conventional tactile and optical criteria, a caries detector dye (1% acid red in propylene glycol), which is claimed to stain 'infected' tissue red, was applied. Fifty-two per cent of cavities showed caries dye stain in some part of the enamel-dentine junction. Subsequent microbiological sampling of dye-stained and dye-unstained sites resulted in the recovery of low numbers of bacteria and revealed no difference in the level of infection of the two sites. It is concluded that the conventional tactile and optical criteria are satisfactory assessments of the caries status of tissue during cavity preparation and that subsequent use of a caries detector dye on hard and stain-free dentine will result in unnecessary tissue removal.

Secondary caries is difficult to diagnose accurately. The purpose of this laboratory study was to investigate various non-invasive clinical and radiographic criteria which might predict the presence of carious dentine beneath the margin of the filling. A total of 331 sites, each 3 mm in length on the tooth restoration margin, were selected on 112 extracted and filled teeth. Thirty of these sites showed obvious carious cavities. Ditching was apparent in a further 70 sites, while 231 sites were clinically intact. Staining of the margin of the filling was recorded and radiographs were taken of posterior teeth. Restorations were then removed and the enamel-dentine junction (EDJ) immediately below the sites was examined for its consistency (hard/soft) and colour (stained/stain-free). Results showed that staining around a filling is not a reliable predictor of softening or discolouration of the dentine beneath. A clinical carious cavity and radiographic evidence of demineralisation indicate soft and discoloured dentine and should trigger operative intervention, while ditching alone should not.