Use of dewatered alum sludge as a substrate in reed bed treatment systems for wastewater treatment.

In this paper, two laboratory-scale simulated reed beds were investigated for the purpose of assessing the feasibility and effectiveness of using dewatered alum sludge as a possible substrate for wastewater treatment reed bed systems. One horizontal subsurface flow setup and one vertical flow setup were used. The horizontal flow system was planted with Phragmites australis while the vertical flow system was left unplanted. Thus, the latter was more akin to a sand filter system, but was examined with the potential use as a planted vertical reed bed system. The influent source used was farmyard wastewater. It is expected that the present study will provide the basis for long-term and large-scale trials in realizing the concept of integrating "waste" into treatment processes. Results obtained so far have shown that the dewatered alum sludge holds great promise as a low-cost resource media for use in reed bed treatment systems. Appreciable and stable performance was obtained during the continuous operation at high hydraulic, organic and phosphorus loadings. In particular, both wetlands achieved over 90% phosphorus removal, reflecting the significant advantage of this novel approach over conventional reed bed treatment systems. However, extensive research into possible surface clogging and possible release of some substances from the sludge to the treated effluent is necessary to ensure reliability of the system. This will help to make the alum sludge-based reed bed environmentally and economically justifiable.

Factors influencing the success of conventional root canal therapy--a five-year retrospective study.

This retrospective study on the outcome of conventional root canal therapy was carried out on patients attending the Eastman Dental Hospital between 1970 and 1982. A minimum follow-up period of 5 years was required for patients to be included in the survey. The characteristics of the resulting sample group, the techniques for canal preparation and obturation and the obturating materials used were analysed. The type of obturating material used had no demonstrable effect on success rate but sex, age, preoperative vitality and periapical pathology were associated with significantly differing success rates. Technique also influenced success rate; the method of canal preparation and the position of the apical seal relative to the radiographic apex were both found to be significant. The overall success rate was 84.29%, representing 692 of 821 teeth included in the survey.

A survey of endodontic procedures performed by practitioners in limited practice.

Patients are sometimes referred for treatment to dentists who limit their practices to endodontics. A survey of consecutive referrals to seven such dentists was undertaken. The most common reasons for such referrals were (i) for the retreatment of a tooth with a previous root filling, (ii) because the referring dentist was unable to control pain and/or swelling, or (iii) because the referring dentist was unable to diagnose the endodontic problem. Only 60 (12.8%) of the 469 reasons reviewed were in teeth that were symptomless, uncomplicated and untouched by the referring dentist.

[Teaching of endodontics in the 11-member nations of the European Endodontic Society]. / L'insegnamento della endodonzia in 11 paesi membri della Società Europea di Endodonzia.

This study was commissioned in 1984 by the Council of the European Society of Endodontology (E.S.E.) in order to discover the extent of endodontic teaching in undergraduate curricula, the methods used in the teaching of the subject and the clinical technique favoured by each school. The survey was conducted with the co-operation of the Country Representatives in eleven out of the fourteen member countries. Each representative was sent a questionnaire and asked to translate it, if necessary, into the appropriate language/languages. These translated questionnaires were sent to the Head of the department responsible for endodontic teaching in each school of that country. The questionnaire inquired into the following subjects: 1) Type of school and teaching arrangements; 2) Teaching concepts; 3) Operative procedures. This study confirmed that endodontic teaching in the schools of the eleven countries that contributed to the survey was fundamentally similar and conformed to what is generally accepted as the conventional approach to the endodontic treatment.