Heat release, time required, and cleaning ability of MTwo R and ProTaper universal retreatment systems in the removal of filling material.
BACKGROUND
This ex vivo study evaluated the heat release, time required, and cleaning efficacy of MTwo (VDW, Munich, Germany) and ProTaper Universal Retreatment systems (Dentsply/Maillefer, Ballaigues, Switzerland) and hand instrumentation in the removal of filling material.


METHODS
Sixty single-rooted human teeth with a single straight canal were obturated with gutta-percha and zinc oxide and eugenol-based cement and randomly allocated to 3 groups (n = 20). After 30-day storage at 37 °C and 100% humidity, the root fillings were removed using ProTaper UR, MTwo R, or hand files. Heat release, time required, and cleaning efficacy data were analyzed statistically (analysis of variance and the Tukey test, α = 0.05).


RESULTS
None of the techniques removed the root fillings completely. Filling material removal with ProTaper UR was faster but caused more heat release. Mtwo R produced less heat release than the other techniques but was the least efficient in removing gutta-percha/sealer.


CONCLUSIONS
ProTaper UR and MTwo R caused the greatest and lowest temperature increase on root surface, respectively; regardless of the type of instrument, more heat was released in the cervical third. Pro Taper UR needed less time to remove fillings than MTwo R. All techniques left filling debris in the root canals.
Department of Operative Dentistry, Dental Materials and Endodontics, Dental School of Bauru, University of São Paulo, Bauru, SP, Brazil. bramante@fob.usp.br
Clovis Monteiro
CM
Bramante
Natasha Siqueira
NS
Fidelis
Tatiana Santos
TS
Assumpção
Norberti
N
Bernardineli
Roberto Brandão
RB
Garcia
Alexandre Silva
AS
Bramante
Ivaldo Gomes
IG
de Moraes
D003786:Dental Pulp Cavity / Q000473:pathology; D003804:Dentin / Q000473:pathology; D004867:Equipment Design; D006171:Gutta-Percha / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007180:Incisor / Q000473:pathology; D008422:Materials Testing; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000737:chemistry; D012389:Root Canal Obturation; D018915:Root Canal Preparation / Q000295:instrumentation*; D016369:Smear Layer; D013499:Surface Properties; D013696:Temperature; D013821:Thermometers; D013997:Time Factors; D019227:Tooth Apex / Q000473:pathology; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry
D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D015035:Zinc Oxide-Eugenol Cement; C074417:Endo-Fill; D006171:Gutta-Percha