L. G. Coldero, S. McHugh, D. MacKenzie & W. P. Saunders
Dental School, Department of Statistics, University of Glasgow, Glasgow, UK.
University of Dundee Dental School, Dundee, UK.

Aim.
To compare in vitro intracanal bacterial reduction using nickel–titanium rotary instruments with and without apical enlargement.

Conclusions.
There was no significant difference in intracanal bacterial reduction when Ni–Ti GT rotary preparation with NaOCl and EDTA irrigation was used with or without apical enlargement preparation technique. It may therefore not be necessary to remove dentine in the apical part of the root canal when a suitable coronal taper is achieved to allow satisfactory irrigation of the root canal system with antimicrobial agents.

I. Miletie, G. Prpie-Mehifie, T. Maruan, A. Tambie-Andrauevie, S. Pleuko, Z. Karlovie & I. Anie
Department of Dental Pathology, School of Dentistry, University of Zagreb, Croatia.
University Hospital of Infectious Diseases ‘Dr Fran Mihaljevib, Zagreb, Croatia.

Aim.
To evaluate the penetration of Candida albicans alone and a combination of bacteria through root canals filled with gutta-percha and one or other root canal sealers, AH26 and AH Plus.

Conclusion.
Leakage in the experimental teeth occurred between 14 and 87 days. Leakage was present in 47% of all samples. From the samples with AH26, 45% leaked bacteria and 60% leaked fungi; whilst from the samples with AH Plus, 50% leaked bacteria and 55% fungi. There was no statistically significant difference in penetration of bacteria and fungi between the sealers.

G. Gambarini & J. Laszkiewicz
Department of Periodontics-Endodontics, University of Rome, “La Sapienza”, Rome, Italy.
Department of Conservative Dentistry, Institute of Dentistry, Medical University, Lodz, Poland.

Aim.
The aim of the present study was to assess debris and smear layer remaining following canal preparation with GT rotary instruments.

Conclusions.
Under the conditions of the present study GT rotary instruments removed debris effectively, but left root canal walls covered with smear layer, particularly in the apical third.

D. M. Z. Guerisoli, M. A. Marchesan, A. D. Walmsley, P. J. Lumley & J. D. Pecora
Ribeirao Preto Dental School, University of Sao Paulo, Ribeirao Preto, Brazil.
School of Dentistry, University of Birmingham, Birmingham, UK.

Aim.
To evaluate smear layer removal by different irrigating solutions under ultrasonic agitation.

Conclusions.
According to the methodology employed, it can be concluded that 1.0% sodium hypochlorite associated with 15% EDTAC is efficient in removing the smear layer from root canal walls. Irrigation with distilled water or 1.0% sodium hypochlorite alone did not produce root canal walls free of smear layer. When groups were examined separately, there were no statistical differences between the amount of smear layer found on canal walls in the cervical, middle and apical thirds.