T. Tsurumachi, M. Hayashi & O. Takeichi
Department of Endodontics, Nihon University School of Dentistry, Tokyo, Japan

Aim.
To describe the clinical management of an unusual dens invaginatus type 2.

Summary.
A case of dens invaginatus in a maxillary lateral incisor with a periapical lesion is reported. The patient presented with pain and localized swelling. Despite the complex anatomy and diagnosis of dens invaginatus , non-surgical root canal treatment was performed successfully.

Key learning points.
• Dens invaginatus may be presented in many forms, and the aetiology of this phenomenon is not fully understood.
• Due to abnormal anatomical configuration, dens invaginatus presents technical difficulties in its clinical management.
• Non-surgical root canal treatment can be performed successfully.

P. V. Abbott
School of Dental Science, University of Melbourne, Melbourne, Victoria, Australia

Aim.
This study was undertaken to determine the incidence of root fractures during post removal, as well as the methods used and the success rates achieved with various post removal devices and techniques.

Conclusions.
This study indicates that, with good case selection, post removal is a predictable procedure. If appropriate techniques and devices are used for the particular type of post being removed, then root fracture is a rare occurrence.

K. Gulabivala, A. Opasanon, Y.-L. Ng & A. Alavi
Department of Conservative Dentistry, Eastman Dental Institute for Oral Health Care Sciences, University College London, London, UK

Aim.
To investigate the root and canal morphology of 351 mandibular permanent molars collected from an indigenous Thai population.

Conclusions.
This study suggests that Thai molars exhibit features of both Caucasian and Chinese teeth.

C. A. Quinlan, D. M. Zisterer, K. F. Tipton & M. I. O’Sullivan
Dublin Dental Hospital
Department of Biochemistry, Trinity College, Dublin, Ireland

Aim.
This work was designed to investigate the potential cytotoxicity of two of the newer dental restorative materials, Spectrum® composite resin and Dyract® AP compomer.

Conclusions.
These results indicate the restorative materials to be potentially toxic, particularly if the degree of light-cure is inadequate.

J. Versümer, M. Hülsmann & F. Schäfers
Department of Operative Dentistry, University of Göttingen, Germany

Aim.
The purpose of this study was to compare several parameters of root canal preparation using two different rotary nickel–titanium instruments: ProFile .04 (Dentsply/Maillefer, Ballaigues, Switzerland) and Lightspeed (Lightspeed Technology Inc., San Antonio, TX, USA).

Conclusions.
Both systems under investigation respected original root canal curvature and were safe to use. Both systems can be recommended for clinical use.