Long-term obturation quality using noninstrumentation technology.

The aim of the study was to evaluate and compare the sealing quality of hand- or vacuum-obturated root canals after hand instrumentation or noninstrumentation cleansing. A total of 60 single-rooted teeth were divided into six comparable groups. The root canals of three groups were instrumented with the balanced-force technique and obturated with gutta-percha condensation. The remaining teeth were cleansed and filled using noninstrumentation technology and the same sealers as with hand instrumentation (AH Plus, Apexit, Pulp canal sealer EWT). After aging the quality of coronal seal was assessed with a dye penetration method after perfusion with the dye under vacuum. The results of this study indicated superior sealing of the machine-filled roots (noninstrumentation technology), compared with laterally condensed conventionally filled root canals.

Comparison of two devices for root canal cleansing by the noninstrumentation technology.

Optimal cleansing of the root canal system is a prime prerequisite for long-term success in endodontics. Recently, a new method and device were presented providing "automatic" root canal cleansing without the need of endodontic instrumentation. Cleanliness results equivalent to or better than those with conventional methods were achieved in considerably less time. The purpose of the present study was 2-fold: (a) optimization of the device to make it applicable to patients and (b) to measure its effectiveness against the predecessor model. A total of 156 root canals of 66 freshly extracted vital human molars were cleansed with the new device and their cleanliness compared with that of 149 canals of 52 molars cleansed previously with the first apparatus. Data indicated that the smaller new machine produced equivalent or better cleanliness results in the root canal system using significantly less irrigant (NaOCl).

Obturation of root canals in vivo with a new vacuum technique.

It was demonstrated in vitro that it is possible to achieve obturation of the root canal system with a system utilizing a reduced pressure of 15 hPa (15 mbar). The purpose of this study was to develop a procedure to reach a vacuum of at least 15 hPa within root canals in vivo. It was also determined if root canals could be obturated in daily practice with this vacuum technique. After hand instrumentation of the root canals a tooth was prepared for obturation of the canals with the new technique by obtaining a tightly fitting attachment to a vacuum pump. The result showed that it was possible in vivo to reach reduced absolute pressures of 10 hPa in roots and to fill the root canal system with the new system.

A new non-instrumental technique for cleaning and filling root canals.

The aim of this in vitro study was to test the ability of a novel non-instrumental technique to prepare and obturate root canals. Cleaning of the root canal system was achieved with a device which was able to develop, under reduced pressure, controlled cavitation. The same device was used for proper drying and subsequent obturation of the root canal system. A total of 55 freshly extracted molars with 120 canals were treated either by the step-back technique and lateral condensation of gutta-percha and AH26 as a sealer or by the new device. The teeth were then sectioned horizontal to the long axis of the root canal and examined by light microscopy. The cross-sectional area, area with residual pulpal tissue and voids were assessed morphometrically. Overall, the treatment with the new device resulted in similar cleanliness and obturation quality when compared with the control group. Total treatment time using the new non-instrumental technique, however, was less than half of that using hand instrumentation.

A novel noninstrumented technique for cleansing the root canal system.

The aim of this study was to develop a machine to clean root canals without conventional instruments. This goal was achieved with a device which was able to develop controlled cavitation in the root canal. Under reduced pressure, alternating pressure fields generated microscopic and macroscopic cavitation bubbles. Subsequently, these vapor-filled cavitation bubbles collapsed, creating hydrodynamic turbulence. These two phenomena allowed the irrigant to penetrate the canal system and then be exchanged with new irrigant. To test the cleaning ability of the device 79 freshly extracted vital molars with 222 root canals were collected. The control group (27 molars, 73 canals) was prepared with the step-back technique using NaOCl (3%) as an irrigant. The three test groups (52 molars, 149 canals) were prepared with the new machine using NaOCl (1, 2, or 3%). The treatment time ranged from 16 to 32 min in the hand group and from 10 to 15 min in the machine groups. The teeth were then prepared histologically and examined by light microscopy. Overall, the treatment with NaOCl (2 and 3%) resulted in similar or better cleanliness in all three root sections when comparing machine and hand instrumentation. In curved canals, however, the apical one third was also significantly cleaner when using the machine and 3% NaOCl than with hand instrumentation. This in vitro study shows that it is possible to clean a root canal system by a noninstrumented technique as well as by conventional hand instrumentation.