Journal of Indian Society of Pedodontics and Preventive Dentistry
Journal of Indian Society of Pedodontics and Preventive Dentistry
                                                   Official journal of the Indian Society of Pedodontics and Preventive Dentistry                           
Year : 2017  |  Volume : 35  |  Issue : 3  |  Page : 244--248

Volumetric evaluation of various obturation techniques in primary teeth using cone beam computed tomography – An in vitro study


NB Nagaveni1, Sneha Yadav1, P Poornima1, KP Bharath2, Mebin George Mathew3, PG Naveen Kumar4,  
1 Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka, India
2 Reader, Department of Pedodontics and Preventive Dentistry, Davangere, Karnataka, India
3 Post Graduate Student, Department of Pedodontics and Preventive Dentistry, Davangere, Karnataka, India
4 Department of Community Dentistry, College of Dental Sciences, Davangere, Karnataka, India

Correspondence Address:
N B Nagaveni
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka
India

Abstract

Aim: The aim of this study was to compare and evaluate the efficiency of five different obturation methods in delivering the filling material into the canals of primary teeth using cone beam computerized tomography (CBCT) scan. Method: A total of fifty prepared canals of primary teeth which further divided into five groups with ten canals in each group were obturated with zinc oxide-eugenol cement using five different obturation methods such as endodontic plugger, lentulo spiral (handheld), lentulo spiral mounted on slow speed handpiece, local anesthetic syringe, and tuberculin syringe. Using CBCT scan, the pre- and post-obturation volume and the percentage of obturated volume (POV) were calculated for each group. The results obtained were statistically analyzed using one-way analysis of variance and Tukey's post hoc test. Results: Following CBCT scan, the method obturated with lentulo spiral mounted to handpiece showed the highest POV value followed by the method of lentulo spiral mounted to handpiece, hand plugger, and tuberculin syringe. Local anesthetic syringe gave the least POV (P < 0.05). Conclusion: Lentulo spiral mounted to handpiece showed the best technique of obturation using CBCT evaluation among the five groups evaluated in primary teeth. However, more studies are highly essential to prove it a boon for estimating obturation quality in primary teeth.



How to cite this article:
Nagaveni N B, Yadav S, Poornima P, Bharath K P, Mathew MG, Naveen Kumar P G. Volumetric evaluation of various obturation techniques in primary teeth using cone beam computed tomography – An in vitro study.J Indian Soc Pedod Prev Dent 2017;35:244-248


How to cite this URL:
Nagaveni N B, Yadav S, Poornima P, Bharath K P, Mathew MG, Naveen Kumar P G. Volumetric evaluation of various obturation techniques in primary teeth using cone beam computed tomography – An in vitro study. J Indian Soc Pedod Prev Dent [serial online] 2017 [cited 2020 Nov 25 ];35:244-248
Available from: https://www.jisppd.com/text.asp?2017/35/3/244/211843


Full Text

 Introduction



Ones broken, a tooth can be mended by the art of dentistry. Preservation and maintenance of teeth and oral cavity in healthy state are the ultimate goal of dentistry. This applies even for the deciduous dentition, especially to maintain the arch integrity as there is nothing which can replace nature's own space maintainer, i.e., primary tooth itself. Apart from preserving primary teeth and maintaining the arch length, it also provides proper guidance of the permanent dentition during eruption. Hence, all the effort should be made to preserve it.[1]

Various therapeutic procedures have been figured out by various dental workers suiting the extent of damage and pathologic involvement of the primary tooth pulp tissue; to name some indirect pulp therapy, direct pulp capping, pulpotomy, and pulpectomy.[1] Out of these options, pulpectomy is indicated when inflammation of the pulpal tissue involves the radicular pulp or when nonvital pulp tissue or traumatic injuries is diagnosed to maintain the affected tooth until normal exfoliation. The treatment consists of extirpation/debridement of the pulp tissue associated with microorganism along with debris from the canal followed by root canal preparation and finally filling the canal(s) (obturation) with an antibacterial, resorbable filling paste to create a three-dimensional (3D) seal to prevent recurrence of bacterial infection.[2]

This procedure is not simple enough as it sounds owing to the morphology of the primary root canal including variation such as lateral branching, connecting fibrils, apical ramification, and partial fusion of canals. These developmental, anatomic, and physiological differences call for an examination of the differences in the criteria for root canal filling techniques in primary teeth. No techniques currently available are near to be ideal.[3]

A 3D seal of the root canal system through obturation hinders microleakage between the root canal and the periapical tissues thus depriving any surviving microorganism of nutrient and prevent toxic bacterial products from entering the periapical tissues. Furthermore, the technique should assure complete filling without spilling of the material periapically with minimal or no voids.

There are various methods available to fill the pulpectomized canals of primary teeth which include plugger, local anesthetic syringe, lentulo spiral, tuberculin syringe, and NaviTip syringe.[4] To confirm the best, various studies have investigated different filling techniques in vivo and in vitro. Most commonly used method to confirm filling quality is the use of a postoperative radiograph which maybeconventional radiographs or new digital imaging. Apart from these, different methods were employed to check for the quality of root filling such as radioisotope,[5] dye penetration,[6],[7] fluid filtration,[8] bacterial leakage,[9] microscopic analysis,[10],[11] clearing techniques,[12] and microcomputerized tomography (CT).[13] However, studies show that these methods have certain drawbacks.

The revolutionary invention of cone beam CT (CBCT) has made many works simpler. It gives 3D volume measurements in a noninvasive manner. Thus, there is no loss of material and it could be used for further research. An extensive literature review shows that no studies have being performed to evaluate the efficiency of different obturation techniques in primary teeth using CBCT. Furthermore, assessments which compared different obturation techniques were performed either on permanent teeth or compared two or three techniques on deciduous anterior teeth. Hence, to fill the gap in our knowledge, this study was designed wherein five different obturation techniques were compared volumetrically with the help of CBCT.

 Methods



Specimen collection

Primary teeth extracted due to reasons such as gross caries or over retention were collected from outpatient Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka. Soft tissue remnants attached to the teeth were removed. Collection, storage, sterilization, and handling of extracted teeth were carried out according to the guidelines and regulations of Occupational Safety and Health Administration.

Out of the teeth collected, fifty canals were selected for the study. The teeth with minimum three-fourth of the original root length, extracted due to gross caries or loss of bone support or over retention were included for the study whereas those with less than three-fourth of the original root length or calcified canals or canal which are difficult to obturate were excluded from the study.

Preparation of teeth specimen

A standard coronal access cavity preparation with diamond fissure bur was done using high speed airotor. Patency of the canals was checked using a 10 K-file. Meanwhile, the working length of the canal was recorded as length of initial file at the apical foramen −1 mm. Root canals were instrumented till file number 30–35. All the canals were irrigated with normal saline and once the preparation was done, they were dried using absorbent paper point. The apex of the root was blocked by small amount of red wax to prevent extrusion of filling material. Canals were numbered from 1 to 50.

Preparation of model

A model of “U” shape was made using modeling wax. Five of such models were made such that it mimicked the natural arch form of human jaw. To these, wax was embedded the teeth specimens such that the tip of roots was inside the wax while rest was exposed. Each specimen or group contained ten teeth. The base of the wax was made flat enabling it to stay stationary on the top of the flat plastic bite plate.

Preobturation scanning

The prepared sample models were then placed onto the biteplate of Kodak 9000 extraoral imaging with tube voltage of 70 KVP and tube current of 2.3 mA. Images displayed on a monitor were inspected by two examiners. Segmentation was performed on consecutive two-dimensional (2D) slices using the magic wand as the region growing tool. Segmentation is semiautomated with manual intervention. After segmentation, the software automatically computed each canal's volume from the stack of segmented 2D slices.

Obturation techniques

The five groups of specimens contained ten teeth in each group. The five groups were assigned as follows. Group 1 for endodontic plugger, Group 2 for lentulo spiral (handheld), Group 3 for lentulo spiral mounted to handpiece, Group 4 for local anesthetic syringe, and Group 5 for tuberculin syringe. The canals were obturated with slow setting zinc oxide-eugenol cement (ZOE) using five different methods. For each sample, one volume unit of powder was mixed with two volumes of liquid to achieve similar creamy consistency of ZOE.

For Group 1, creamy consistency of ZOE was obtained as described earlier. This cement was filled in a liquid anesthetic syringe with a 27-gauge needle. Ten canals were obturated by injecting the cement into the canal using this syringe. Material was injected into the canal till the canal orifice appeared to be filled with cement.

In Group 2, ZOE mixed as described earlier was used to fill a tuberculin syringe (needle 29-gauge and length - 11 mm). This paste was then injected into ten canals. Canals were filled till the backflow of cement is observed in the orifice.

In Group 3, ZOE was mixed to a thicker consistency. This cement was pushed into canal of 10 canals with endodontic pluggers. Cement is filled in 3–4 increment to fill the canal.

In Group 4, ZOE mixed in creamy consistency was similar as done for first two groups. This cement was introduced in canal using handheld lentulo spiral. Lentulospiral used was one size smaller than the last size file used for root canal preparation. Lentulo spiral with the cement will be inserted into the canal with clockwise rotation, accompanied by vibratory motion to allow the material to reach the apex and withdrawn in the same fashion.

In Group 5, ZOE was mixed in the same manner. Canals were filled using lentulo spiral mounted on slow speed handpiece. For ease of handling, the instrument's length was reduced by cutting with sharp scissors. Lentulo spiral was then inserted into canal rotated in clockwise direction and withdrawn from canal while still rotating.

To control the delivery of material, a rubber stopper was placed around each instrument according to the predetermined working length. For each sample when canals were assumed to be filled, a wet cotton pellet was used to lightly tamp the material into the canals.

Postobturation scanning

Following obturation with ZOE in respective groups using different obturation techniques, a second CBCT scan was done to determine the volume of filling material in all the groups. This volume was considered as (Y). Percentage of obturated volume (POV) was calculated using the formula POV = Y/X × 100 in all five groups. The values obtained from five groups were statistically analyzed using one-way analysis of variance (ANOVA) (among five groups) and a Tukey's post hoc test (within the same group) using software SPSS version 1.7 (SPSS Inc., Chicago, IL). The level of significance was set at 0.005 [Figure 1].{Figure 1}

 Results



In all five groups containing ten teeth in each groups, CBCT scan done was done to obtain the volume of the canal before obturation and volume of the obturated material and finally to calculate the POV. The volume of the root canals studied before obturation were 0.05 ± 0.03 mm3, 0.04 ± 0.02 mm3, 0.04 ± 0.03 mm3, 0.04 ± 0.02 mm3, and 0.04 ± 0.02 mm3 for Group 1, 2, 3, 4 and 5, respectively, whereas the volume of obturated canals in each groups were 0.03 ± 0.02 mm3, 0.04 ± 0.03 mm3, 0.04 ± 0.03 mm3, 0.02 ± 0.05 mm3, and 0.03 ± 0.05 mm3, respectively [Table 1]. The POV values obtained for Group 1 were 79.14 ± 2.18; for Group 2, it was 88.91 ± 1.71; Group 3 had 89.43 ± 2.6; Group 4 showed 63.84 ± 3.34; and for Group 5, it was 73.60 ± 3.9.{Table 1}

The results of ANOVA test showed that there was significant difference in the POV of different groups (P < 0.05). The Tukey's post hoc test showed that the postobturation volume was the maximum for Group 3 (lentulo spiral mounted to handpiece) followed by Group 2 (lentulo spiral handheld) than Group 1 (plugger) and Group 5 (tuberculin syringe), and finally, the Group 4 (anesthetic syringe) showed least volume. Group 4 had a significant difference against all other groups. Group 5 showed a significant difference from all other groups except Group 1. Similarly, Groups 2 and 3 except from each other had a significant difference from other groups [Table 1].

 Discussion



A good obturation is the essence of an ideal pulpectomy in children. Since ages various techniques have evolved and tested by different means to establish the best method to obturate primary teeth root canals. The present study is one among these efforts, wherein five different commonly used methods to fill a canal are compared for their efficiency and efficacy.

Penetration of dye and bacteria or radioisotopes, clearing techniques, and radiographic assessment are various laboratory approaches used to evaluate the quality of obturation. However, drawbacks such as loss of material or 2D view hindered these procedures from giving full proof results.[14] Therefore, an idea to use CBCT scan came which prevent either of both. An extensive research did not reveal any study showing CBCT evaluation in estimating obturation quality from 3D in primary teeth.

A novel technology in the dentomaxillofacial imaging is the use of CBCT; a nondestructive technology provides 3D interpretation of the specimen. Although micro or spiral CT scan has been used for the volumetric evaluation of obturation materials in primary teeth, the CBCT has various advantages over spiral CT, such as lower effective radiation doses, lower costs, fewer space requirements, easier image acquisition, and interactive display modes such as multiplanar reconstruction and the specimen can be used for the future research. Recent studies have shown CBCT provides a precise method of measuring the amount of root dentin removed by various endodontic instruments. Therefore, the present study has designed to evaluate the volumetric comparison of different obtruration techniques in primary teeth using CBCT imaging.[15],[16]

The present study showed that out of the five techniques compared, lentulo spiral showed the best efficiency in delivering the paste into the canals. Other studies which showed similar results were the one conducted by Memarpour et al.,[2] Subba Reddy and Shakuntala,[17] and Aylard and Johnson [18] where all studies showed lentulo spiral method gave best obturation in terms of minimum number of voids and length of obturation. Memarpour et al. compared anesthetic syringe, NaviTip syringe, pressure syringe, tuberculin syringe, lentulo spiral, and plugger and judged on the basis of length of obturation and number and sum of voids. Lentulo spiral proved to be the best in length of obturation followed by NaviTip, whereas it was reverse in case of sum and number of void.[2] When techniques were compared in vivo condition by Subba Reddy and Shakuntala in a 5–9-year-old children; lentulo spiral was superior for depth of fill.[17] Aylard and Johnson tested techniques of endodontic pressure syringe, the mechanical syringe, the lentulo spiral, the Jiffy Tube, and the tuberculin syringe and a significant difference in all where lentulo spiral stood to be the better in curved canals and equal to pressure syringe when used for straight canals.[18] When comparison of lentulo spiral was done with pressure syringe by Greenberg; lentulo spiral gave better results.[19] Results similar to our study were found by Bawazir and Salama [4] where nonsignificant difference was found between handheld and handpiece mounted lentulo spiral in obturating the primary canal.

Even when used with material like calcium hydroxide, lentulo spiral has proved to be the best as shown by Torres et al., Peters et al., Kahn et al.[20],[21],[22] Lentulo spiral was only second to pastinject in filling the canal with calcium hydroxide as shown by Deveaux et al. and Oztan et al.[23],[24] In studies done by Simcock and Hicks [25] and Staehle et al.,[26] quantity of filling done by anesthetic syringe and lentulo spiral was almost same.

On the contrary, studies done by Guelmann et al.,[27] Grover et al.,[28] and Tan et al.[29] showed result opposite to that seen in the present study. However, such results were obtained when lentulo spiral was compared to techniques such as NaviTip system, pastinject and specially designed paste carrier, respectively. There are other studies such as one done by Dandashi et al. which showed no significant difference between the lentulo spiral, pressure technique, and packing technique.[30]

Thus, when weighed by the number of studies and their results, it is evident that lentulo spiral proved to be better than other conventional techniques. Other added advantage of this instrument is its design which makes it very flexible; which makes it efficient to work in characteristic narrow and curved canals of primary teeth. However, it also comes with some disadvantages such as risk of fracture and danger of over obturating the canal which can be mastered with practice.[2] Although techniques such as NaviTip system and pastinject are proved to be better than it, these have disadvantages such as complexity and need to disassemble if extramaterial required which waste the precious clinical time. Furthermore, after use, it has to be cleaned immediately which is not possible every time, especially on a busy day and it is still cumbersome with uncooperative children.[30].

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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