8/4/2019 Removing Gutta-percha in tic Re Treatment

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Clinical Significance. The challenge C-shaped cross-sectional root anatomy presentsto the clinician lies in the thickness, or lackthereof, of the canal walls that are considerablymore thin than apparent, as suggested on x-ray.Perforation when filing or fracture duringobturation is a potential threat.

Gao Y, Fan B, Cheung GSP, et al: C-shaped canal system in mandib-

ular second molars part IV: 3-D morphological analysis and trans-

verse measurement. J Endod32:1062-1065, 2006

Reprints available from B Fan or M Fan, Key Lab for Oral Biomedical

Engineering of Ministry of Education, School & Hosp of Stomatol-

ogy, Wuhan Univ, 65 Luoyu Rd, Wuhan 430079, China; e-mail:

bingfan8@hotmail.com

Removing gutta-percha in endodontic retreatment

Background.If root canal therapy fails, the preferred

approach, being the most conservative choice, is retreat-

ment. Retreatment is undertaken to regain access to the

apical foramen by completely removing all root canal filling

material, permitting sufficient cleaning and shaping of the

system and final appropriate obturation. The gutta-percha

can be removed through several methods, including new

flexible rotary nickel-titanium (NiTi) files in a slow-speed

handpiece. The efficacy of 2 rotary NiTi instruments in

removing gutta-percha during root canal retreatment

was evaluated in comparison with hand instruments using

Hedstrom files.

Methods.A total of 60 extracted human single-rooted

anterior teeth and premolars were instrumented and obtu-

rated using the laterally condensed gutta-percha technique.

Three groups of 20 teeth each were randomly formed.

Two NiTi instruments, the ProTaper and K3, and hand

instruments were used to remove the gutta-percha filling

material. Roots underwent longitudinal splitting, then

were digitally reproduced using a scanner. Areas where ma-

terial remained were identified. In addition to efficacy, time

required for removing the gutta-percha and amount of

apically extruded debris were recorded.

Results.The amount of filling material left by the 2 ro-

tary NiTi instruments was significantly less than that left by

the hand instruments (Table 1). The NiTi instruments also

required significantly less time to remove the filling material

than the hand instruments. The amount of debris removed

was the same for each of the 3 techniques.

Discussion.The removal of gutta-percha was

achieved more quickly and more completely using the

NiTi instruments than the hand instruments. All the instru-

ments left some gutta-percha in the root canals.

Clinical Significance.Retreatment of failingroot canal treatments depends on gaining ac-cess to the apical foramen, totally debridingthe canal, and adequately sealing it. In thisstudy, automated instrumentation was fasterand more effective than hand instruments in re-moving the old filling. No significant difference

was noted in the amount of debris extrudedapically.

Saad AY, Al-Hadlaq SM, Al-Katheeri NH: Efficacy of two rotary NiTi

instruments in the removal of gutta-percha during root canalretreatment. J Endod 33:39-41, 2007

Reprints available from SM Al-Hadlaq, Dept of Restorative Dental

Sciences, Div of Endodontics, College of Dentistry, King Saud

Univ, PO Box 60169, Riyadh 11545, Saudi Arabia; e-mail:

smhadlaq@ksu.edu.sa

Table 1.Remaining Filling Material in Each Third ofthe Canal (Expressed as Percentage of Area of EachThird) for Each Technique

Technique N Region Mean SD

Hand 20 Apical 15.89 10.29

Middle 11.32 5.94

Coronal 4.50 3.51

ProTaper 20 Apical 7.81 5.03

Middle 5.53 3.51

Coronal 2.78 1.79

K3 20 Apical 8.07 5.14

Middle 5.73 3.92

Coronal 3.10 2.24

(Thisarticle waspublished inJ Endod, 33, SaadAY, Al-Hadlaq SM, Al-Katheeri

NH, Efficacy of two rotary NiTi instruments in the removal of gutta-percha

during root canal retreatment, 39-41, Copyright American Association of

Endodontics (2007).)

Volume 52 Issue 5 2007 287

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