ENDO, 04/2007

The use of root/tooth resections in the retention of compromised teeth has been all but abandoned due to the success of contemporary implant usage. However, these resective procedures are viable treatment considerations in the retention of natural tooth structure and can provide the patient with a reasonable alternative in many critical clinical situations. The understanding of when to use these procedures and how to integrate the necessary endodontic, periodontic and prosthetic applications are essential to success. When done properly and when the patient practices good oral hygiene, the success rate can be quite high. Palabras clave: prognosis, rationale, root resections, technique, tooth resections

A variety of instruments and techniques has been developed and described for the preparation of severely curved root canals. This paper reviews the ability of different automated devices and torquelimited handpieces when using rotary nickel-titanium instruments for root canal preparation. In summary, there is currently no scientific evidence that the choice of a special automated device has any clinical influence on the outcome of endodontic treatment. Palabras clave: automated devices, canal straightening, curved root canals, instrument fracture

Nickel-titanium (NiTi) rotary instruments are increasingly popular for removal of root canal fillings. In the present paper, previously published studies on cleanliness, working time, fractures, canal aberrations, apical extruded debris and rotational speed during retreatment are reviewed. Recent studies have shown that FlexMaster, K3, ProTaper and RaCe performed well for retreatment of straight root canals. For removal of filling materials from curved root canals, RaCe seemed to be an adequate instrument. However, compared with hand files the abovementioned instruments neither improved root canal cleanliness nor reduced working time. Overall, there are more instrument fractures with NiTi instruments compared with hand files. Further studies should be performed to determine the optimum rotational speed and torque including instrumentation sequence when using NiTi instruments for retreatment. Palabras clave: gutta-percha, nickel-titanium, root canal retreatment, rotary instruments

Dens invaginatus is a malformation that can arise in any tooth, but cases in molars are rare. A young adult patient in good dental health presented with an extensive infection of his right maxilla, and a diagnosis of acute periodontal abscess was made. Further investigation revealed acute periapical periodontitis arising from a necrotic third molar pulp. With the tooth extracted, a rare and seldomly reported case of a maxillary third molar dens invaginatus was revealed. Micro CT is useful for studying this type of malformation. Palabras clave: dens in dente, dens invaginatus, diagnosis, malformation, micro computer tomography

During apical surgery, it is fundamental to keep the root apex free of blood and humidity for placement of retrograde filling materials. A new device, fabricated with silicone, was designed for apical isolation for accomplishment of retrograde obturation. This device is economic, disposable, and easy to use and keep in place. Palabras clave: apical isolation, apical surgery, haemorrhage, retrograde obturation, root resection, surgical endodontics

In the present case report, resurgery of a failed surgical case is discussed. The reasons for failure of the original treatment are explained. Palabras clave: amalgam, apical surgery, MTA, root-end filling

Objective: To demonstrate the importance of using a matrix for treatment of root perforations with MTA (mineral trioxide aggregate), and to describe the treatment technique. Methods: The matrix can be created with calcium sulphate, resorbable collagen or calcium hydroxide. When calcium sulphate is used, the material should be carried through the perforation into the bone cavity in the periodontium until the material reaches the level of the external root surface. MTA is then placed in the perforation. Conclusions: Utilisation of a calcium sulphate, resorbable collagen or calcium hydroxide matrix is advisable when treating perforations with MTA, in order to avoid material extrusion into the periodontium. Palabras clave: calcium hydroxide, calcium sulphate, collagen