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The clinical case presented is the demonstration of a multidisciplinary approach to a complex treatment. A precise methodology is important to ensure that the treatment objectives are clear to all the teams. The aim of the treatment is to restore dentofacial harmony to a young, 22-year-old, female patient showing severe attrition of the anterior teeth. The direct effect of this is an ageing of the smile. This type of multidisciplinary treatment, which seems complicated at first, is greatly simplified once time has been spent on the diagnosis and treatment plan: it thereby becomes a succession of clinical stages.

Waste stabilisation pond treatment was widely developed during the 1980s in France, where there are now over 3,000 plants. Desludging the ponds has now become essential. In 19 primary facultative ponds, in operation for 12-24 years, the net average sludge accumulation rate was 19 mm/yr. The average per capita accumulation rates ranged from 0.04-0.148 m3/person.year (mean of 0.08 m3/person.year). In primary facultative ponds the volume of sludge represented 15-39% of the total volume of the basin. A filling rate above 30% necessitates desludging. In France, a desludging interval of 15 years is recommended for primary facultative ponds. The cost evaluation of desludging and landspreading showed differences according to the desludging technique used. Desludging after emptying the water had an average cost of 38 Euro/m3 of sludge with 10% dry solid (range from 20 to 83 Euro/m3). Under-water desludging was 50% more expensive. Although desludging is carried out only after several years of operation, its cost must be allowed for in the annual operation and maintenance costs of the process. It can be estimated to be 3 ł/person.year. Even with this additional cost, waste stabilisation pond treatment remains less expensive than other treatment processes.

The WSP system serving Mèze and Poussan (French Mediterranean coast) was constructed in 1980 and enlarged and upgraded from 1994 to 1998. Water quality along the waste stabilisation pond to (WSP) system has been monitored over the years, thus allowing us to assess the influence of enlargement and upgrading works. A significant enhancement of the average microbiological quality of the effluent was observed, with respective E. coli and streptococci average abatements of 4.1 and 3.4 log. units. Former seasonal variations of microbiological removal have vanished. The contribution of the different ponds to the disinfection performance of the WSP system was analysed. A microbiological quality model was proposed to evaluate the die-off kinetics related to the different ponds and as a tool for the design and management of WSP systems. Though the relationships between die-off coefficients and environmental factors appeared somewhat frail, this modelling is considered a promising approach for the prediction of WSP microbiological performance.

To assess the biocompatibility of a third-generation dentinal adhesive that uses a smear layer conditioner (Scotchbond 2), Class V cavities were prepared and restored in vivo, following a standardized protocol, in 32 human premolars to be extracted for orthodontic reasons. Histologic observation showed seven slight, five moderate, and one severe reaction short term, while 11 slight and three moderate reactions were observed long term. It appeared that the intensity of the reactions decreased with time. Bacteria were observed on only five teeth, and no correlation could be established between the presence of bacteria and the intensity of the reactions. It seemed that the conditioning of the smear layer, although it might have rendered the residual dentin more permeable, limited percolation phenomena by increasing adhesion. Although only one severe reaction was observed, it is mandatory in a clinical setting to place a protective lining near the pulp.

To assess the biocompatibility of an adhesive system, standard Class V cavities were prepared in vivo in human premolars that were to be extracted for orthodontic purposes. Histologic observation revealed that the Gluma Bond System elicited slight to severe pulpal responses, altered odontoblastic layers, and inhibited dentinogenesis. These alterations were observed after in vivo periods of up to 120 days. In this experiment, the dentinal adhesive was polymerized separately from the composite resin, a procedure not recommended by the manufacturer. This may explain the differences in the present results and those reported by the manufacturer.

During life, the modifications of the dental pulp are important mostly in the root portion. This area, more than the coronal part of the tooth is submitted to involution and histologic dedifferentiation. Fibrosis and calcification occur leading to severe difficulty in performing endodontic treatment.

In the albino rat, at the 21th day of gestation, the capillaries entered the stellate reticulum of the molar and came into contact with the stratum intermedium. This vascular penetration was followed on the 10th day of age by a connective penetration. The stellate reticulum was thus disorganized and was built up by small epithelial islands surrounded by collagen and reticulin fibrils. Finally, the reduced enamel epithelium fused with the oral epithelium and formed the epithelial attachment. After a trophic role, the vascularization, with the help of the connective tissue penetration, had a destructive function. Both vascularization and connective tissue invasion contribute to the enamel organ involution.