Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT05128266 |
| Other study ID # |
Oss-R-233 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
January 1, 1991 |
| Est. completion date |
December 31, 2019 |
Study information
| Verified date |
May 2023 |
| Source |
Catholic University of the Sacred Heart |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
The aims of this retrospective analysis are (1) to evaluate the success rate of a
non-surgical retreatment of teeth with broken file instrument into the canal using
ultrasounds, microscope and a modified spinal needle, (2) to assess the outcome of the
treatment if the remaining fragment was left, bypassed or removed from the root canal in
terms of survival rate of the treated teeth after a 5-years follow up period.
Description:
The fracture of an endodontic instrument is a frustrating phenomenon, both for practitioners
and patients, that can compromise the cleaning and shaping procedures of the root canal
treatment, with a potential impact on the treatment outcome. In the past decades, the advent
of rotary nickel titanium instruments resulted in an increased incidence of instrument
separation.
Two mechanisms have been reported in order to describe the fracture of an endodontic
instrument inside the root canal: torsional stress and cyclic fatigue. Cyclic failure is due
to the constant tension and compression which insists on the file when it shapes the maximal
root canal curvature area. Torsional failure occurs when the tip of the instrument locks on
the wall of the root canal while the shafts keeps rotating, and the torque exceeds the
plastic limit of the metal.
Several studies focused on causes and factors influencing the weakening of endodontic
instrument after clinical use, and some recommendation were given trying to minimized the
risk of instruments breakage. Nevertheless, this problem can still occur, even to an
experienced operator, making the achievement of a correct and predictable root canal final
treatment uncertain.
Due to their complexity, many of these cases are approached by extraction and implant
replacement of the so evaluated "hopeless" tooth. Treatment decisions can vary widely among
dentists and dental specialists and may be based more on personal values and experience than
an objective analysis of treatment benefits, risks, costs, prognosis, and alternatives.
At present, there is no standardized procedure for safe and consistently successful
instrument fragment removal in the dental literature.
Different devices, techniques, methods, and protocols used for removal of separated
instruments are described in literature. Unfortunately, there is a lack of high-level
evidence, since most of the papers refer to clinical case report.
Until the beginning of endodontics, dentists have had to face this problem and already in the
last century Masserann invented an instrument to remove obstacles in the root canals. Some
authors believe that Masserann instrument used by expert hands does not expose the tooth to
the root fracture, but this risk remains very high. Several other instruments were invented
as a result, many of them similar to the Masserann extractor, others using micro tweezers or
cyanoacrylate glue.
To solve the problem of root canal obstruction due to fragments of root canal instruments,
some authors make use of the technique of intentional reimplantation after retreatment of the
tooth out of the mouth. Recently, some authors have also used the Nd: YAG laser to remove
broken instruments in the canals. Laser energy has been used to melt the solder, connecting
the separated instrument with the brass tube.
Furthermore, the literature is not clear about the actual need to remove the instruments from
the root canals, neither about the percentage of successes in case of bypassing the fragment
or about the persistence of the instrument in the root canal.
Independently from the technique, the optimal management of instrument fragments during root
canal treatment is crucial in order to enable sufficient debridement and obturation of the
root canal system. However, all clinicians agree that the best help in this procedure came by
the combined use of ultrasound and the operative microscope. These two devices used in
combination allow a more efficient and accurate work, lowering the risk of weakening the
canal wall or create root perforations.
The aims of this retrospective analysis are (1) to evaluate the success rate of a
non-surgical retreatment of teeth with broken file instrument into the canal using
ultrasounds, microscope and a modified spinal needle, (2) to assess the outcome of the
treatment if the remaining fragment was left, bypassed or removed from the root canal in
terms of survival rate of the treated teeth after a 5-years follow up period.
