ENDO, 03/2013

Root canal preparation with only one nickel-titanium instrument used in reciprocation has been recently introduced. New endodontic systems using this concept, such as Reciproc and WaveOne, have also been developed. The purpose of this review was to identify publications regarding the evaluation, to present comprehensive and critical summaries of current knowledge, and to provide an update of the single file reciprocating concept. Keywords: reciprocation, single file, Reciproc, WaveOne

In 2011 the Reciproc System was introduced to the market by VDW (Munich, Germany) as a single file reciprocating system. It is claimed that root canals can be completely prepared with only one Reciproc instrument. This case series describes the treatment of four teeth needing root canal treatment by using the Reciproc System. The illustrated cases show that root canal treatment as well as endodontic retreatment can be safely carried out with Reciproc instruments. Keywords: NiTi, reciprocating technique, Reciproc, root canal treatment

Great progress has been made over the years in the technology of rotary nickel-titanium file systems. Nevertheless, both the oldest and the newest systems all use the same principle of a rotating blade with flutes, designed to carry off or contain the cut material and/or debris. While this concept may provide adequate results in narrow, straight canals with round cross sections, it has substantial limitations when oval or curved canals are concerned. Such canals are very common. The Self-Adjusting File (SAF) system is based on a new and different concept that is aimed at overcoming the limitations of current rotary file technology. This review aims to familiarise the reader with the new concept and technology of the SAF system and to individually discuss the major endodontic challenges that are yet to be conquered by rotary file technology. The ways by which the new SAF system overcomes these challenges will be explained, based on 32 research papers that were published over the past 3 years. A new concept for root canal cleaning and shaping will be presented and justified: the concept of 'minimally invasive endodontics', which has been made possible by the new SAF technology. Keywords: minimally invasive endodontics, NiTi Files, rotary files, SAF, Self-Adjusting File

The aim of the present paper is to provide an overview of the recently introduced root canal single file preparation system, One Shape (Micro Méga, Besançon, France). In contrast to some other single file systems, the One Shape file is used in continuous rotation, as known from many former multiple file rotary NiTi systems for root canal preparation. The unique design of the One Shape instrument incorporates a variety of different cross sections along the active length of the file, which offers an optimal and improved cutting action in three zones of the root canal. Each instrument has been electropolished to enhance cutting efficiency. One Shape's flexibility and unique downward movement ensures a highly effective apical progression. Minimal fatigue along the length of the entire file virtually eliminates the risk of accidental instrument separation. The One Shape instrument is actually available with a safety tip in size 25 at the tip with a continuous 0.06 taper. It is delivered in a sterile blister, as done by many other manufacturers, and should be used for one tooth only and then discarded. It is designed for a maximum of three or four canals in one tooth and should not be sterilised, because the cutting efficiency decreases severely. Practitioners can use their existing endodontic motor with the One Shape instrument. Conclusions: One Shape is optimally designed to prepare the majority of root canal configurations. One Shape is one of the few single file instruments used in continuous clockwise rotation for a quick and probably safe root canal preparation. Keywords: continuous rotation, NiTi rotary files, root canal preparation, single file systems

Objectives: This study evaluated the influence of reciprocating movement on the fatigue life of root canal instruments subjected to static and dynamic tests. Materials and methods: The rotary NiTi instruments used in this study were WaveOne and ProTaper F2 (both from Dentsply Maillefer, Ballaigues, Switzerland). The instruments were initially subjected to a cantilever-bending test, then to static and dynamic fatigue tests. WaveOne instruments were operated in reciprocating movement and ProTaper in continuous rotation. Results: The mean bending resistance values (maximum load in grams) of the instruments were as follows: WaveOne = 544.8; ProTaper F2 = 555.4. No significant difference was observed between the instruments tested (P > 0.05). The mean time to fracture (in seconds) of the instruments subjected to static and dynamic tests were as follows: WaveOne = 93.5 (static) and 267.6 (dynamic); ProTaper F2 = 57.8 (static) and 94.1 (dynamic). Student's t test revealed significant differences in all tests (P < 0.05). Conclusion: The findings revealed that instruments operated in a reciprocating movement and in the dynamic testing model presented prolonged fatigue life. Keywords: dynamic test, fatigue fracture, fatigue resistance, flexibility, reciprocating movement

Aim: The most common anatomy for the maxillary first molar is the presence of four root canals. However, other configurations regarding the number of root canals have been reported. The purpose of this paper is to present two cases with five root canals diagnosed during an endodontic retreatment. Materials and methods: Diagnosis was made and the endodontic retreatment was purposed and performed. A dental operating microscope was used for better understanding of this anatomy and especially looking for possible undetected canals along the developmental lines and grooves. Results: Both cases had undergone previous root canal treatments, which had failed. Both teeth had an anatomic configuration with five root canals with previously undetected MB2 and DB2, with both mesial and distal roots presenting a Vertucci Type II root canal configuration. The recall radiographs showed periapical healing. Conclusions: Although it is an uncommon configuration, the presence of both MB2 and DB2 may be present. The failure to identify the correct anatomy and locate all root canals may lead to treatment failure. The discovery of these missed canals in the endodontic retreatment of the presented cases might have been one of the reasons for retreatment success. Keywords: anatomy, molar, pulp chamber, root canal preparation, root canal therapy

The success of root canal therapy implies a thorough knowledge of the internal as well as the external dental anatomy, in addition to its variations. An aberrant morphology of the root canals can be observed in any tooth, even in a maxillary lateral incisor. This case report looks at the root canal treatment of a maxillary lateral incisor fused with a supernumerary tooth, which shows large periapical radiolucency. This treatment was successfully carried out with the aid of computed tomography (CT) and an operative microscope. Keywords: computed tomography, fused teeth, maxillary lateral incisor, operative microscope, supernumerary tooth, talon cusp

The purpose of treating a furcal perforation is to seal the artificial communication between the endodontic space and the periradicular tissue to prevent alveolar bone resorption and damage to the periodontal ligament. These complications are not infrequent in cases of large furcal and/or old perforations, which have a worse prognosis than recent, small, coronal and apical perforations. Mineral trioxide aggregate (MTA) is widely used to seal perforations, because of its biocompatibility and sealability. This case report describes the management of a large furcal perforation in a mandibular first molar. Although most of the pulpal floor was destroyed and the roots were damaged, an attempt was made to repair the defect and restore the tooth. The perforation was cleaned with saline solution and ultrasonic tips. Finally, the perforation was sealed with MTA and the tooth restored coronally. A 21-month recall showed no evidence of periodontal breakdown, no symptoms, and complete healing of the surrounding periodontal tissue. Keywords: biocompatibility, furcal perforation, MTA, root perforation, wound healing