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Azerbaycan Saytlari

 »  Home  »  Endodontic Articles 7  »  A preliminary study of the percentage of gutta-percha-filled area in the apical canal filled with vertically compacted warm gutta-percha
A preliminary study of the percentage of gutta-percha-filled area in the apical canal filled with vertically compacted warm gutta-percha
Discussion - References.



Discussion.
When the dimensions of the root canal are not sufficiently large, the placement and replacement of the irrigant solution is restricted. Various investigators have found the apical root canal to be less clean than the middle and coronal portions of the root canal (Senia et al. 1971, Cofiae & Brilliant1975,McComb & Smith1975, Svec & Harrison 1977, Littman 1977,Wu & Wesselink 1995). This suggests that bacteria remain in the apical canal. If the root ¢fillings fail to ensure a long-term seal, seepage of tissue £fluids may provide the residual bacteria with a nutritive substrate, and the growth of the remaining bacteria in the apical root canal may cause the persistence of periapical lesion (Nair et al.1990, Molander et al.1998). The apical root ¢filling should provide a seal, especially because after post space preparation only the apical root ¢filling of 3 or 4 mm in length is left, and the cemented post may leak (Fogel1995,Wu et al.1998). Unfortunately, the quality of the root ¢filling obtained by warm vertical compaction has been found to be compromised 2 mm from the apex (Silver et al.1999, Wu et al.2001a). In order to ascertain why this is so, the PGFA was measured 1.5 mm from the AF, which in this study was considered the apical end of the root ¢filling.
No sealer was used although generally recommended. In this study, percentage of gutta-percha ¢filled canal area was measured. If sealer had been used, not only the width of the root canal or the depth of heat application, but also the size of the sealer ¢filled canal area would have been avariable. The larger the sealer ¢filled area, the smaller the gutta-percha ¢filled area. Because it would be difficult to standardize the amount of sealer in the apical canal, no sealer was used in this study and other similar studies (Smith et al. 2000). Although including sealer may facilitate gutta-percha movement, the reasons to leave sealer out were more important; and besides, both groups were treated in the same way. Without a sealer, high PGFAs (average 96.1%) were achieved in the 2-mm group, demonstrating that the low PGFA in the 4-mm group was not the result of the decision not to use sealer.

Figure 3. The cross-section of an extremely large root canal from the 2-mm group. The canal area was 0.55 mm2, larger than a #80 file. The PGFA was 78.9%. Two large areas were left unfilled (original magnification 50x).

The cross-section of an extremely large root canal from the 2-mm group

Figure 4. A cross-section from the 4-mm group. The canal area was 0.31mm2, comparable in size to the one shown in Fig.1. Gutta-percha was not heated sufficiently, leaving unfilled space. The PGFA was 80.6%(original magnification 50x).

A cross-section from the 4-mm group

Figure 5. Another cross-section from the 4-mm group. The canal area was 0.38 mm2, comparable in size to the one shown in Fig. 2. The PGFA was 66.7%. A large unfilled area can be seen (original magnification 50x).

A large unfilled area can be seen

Figure 6. Percentage of PGFA at 1.5 mm from the AF (2-mm group).

Percentage of PGFA at 1.5 mm from the AF

Figure 7. Percentage of PGFA at 1.5 mm from the AF (4-mmg roup). The PGFAs were lower in wide canals.

The PGFAs were lower in wide canals

In many cases spaces were found that were not ¢filled with gutta-percha (Figs 3-5). Whether these spaces can be completely ¢filled with sealer depends on the amount of sealer available in the root canal close to the AF. If sufficient sealer is available, the canal can be sealed before the dissolution of the sealer (Kontakiotis et al. 1997).
It was assumed that heat can be transferred about 4 mm apically along the gutta-percha cone (Ruddle 1994), and that therefore, the gutta-percha in the entire apical root canal may be expected to have been heated after the application of heat 4 mm from the AF. However, in this study relatively low PGFAs were achieved in the 4-mmgroup (Figs 4-6), indicating that the gutta-percha 1.5 mm from the AF was not always heated sufficiently. Therefore, the PGFA reached 100% in only 13% of the canals. When heat was applied 2 mm from the AF, however, a PGFAof100%was achieved in 70%of root canals.
In order to standardize the size of the AF, a size 30 ¢le was used to prepare the canal up to the AF. The vertical compaction extruded gutta-percha in seven teeth (12%). It has been found that, in general, warm guttapercha techniques extrude more gutta-percha than cold lateral compaction (ElDeeb 1984, Gutmann et al. 1993). In comparison with the other warm gutta-percha techniques, gutta-percha extrusion occurred less frequently during vertical compaction, probably because the gutta-percha in the most apical root canal could not be heated. It may be assumed that extrusion will occur more frequently when heat is applied 2 mm from the AF than when it is applied 4 mm from the AF. However, the multiple linear regression did not bear out this assumption, probably owing to the small sample size. On the other hand, although in the 2 mm group gutta-percha extrusion occurred in more cases, the amount per extrusion was small (Table 2). Material extrusion is dependent on apical size. Although all canals were prepared to the AF using a size 30¢le, the size of the original AF could be larger than size 30 in many canals.
Another factor that influenced the PGFA was the width of the apical root canal (P ј 0.038). Although in this study, all canals were instrumented to the same size, the cross-sectional canal area varied from 0.15 to 0.69 mm2, indicating that many original canals were wider than the largest instrument used. There was a 4.5-fold difference between the largest and smallest canals. A single gutta-percha cone of the same size was placed in each canal. The amount of gutta-percha was sufficient to ¢ll the small canals but insufficient to ¢ll the very large ones (Fig. 3). Tug-back was achieved in all canals, clearly, this procedure did not assure that the amount of gutta-percha was sufficient. The association between the PGFA and the canal area was less significant in the 4-mm group (Fig.7) than in the 2-mm group (Fig. 6), because the heat applied in the 4-mm group was often insufficient, which also influenced the PGFA.
Although great differences in canal dimension exist between the largest and smallest canals, clinically it is impossible to know which canal is large. It has been found that the ¢first ¢le that binds does not measure the apical diameter (Wu et al. 2002). Therefore, it is not always avoidable that in some cases insufficient amount of gutta-percha is present in the apical canal, and that the apical ¢filling contains more sealer. Heating to 2 mm from the AF promoted the PGFA in those not so wide canals only, but did not solve the problem in wide canals (Figs 3 and 6). On the other hand, heating to 2 mm leads to a higher risk of extruding material. When sealer is used, more extrusion is expected. The apical extrusion of material beyond the apex has been found in clinical studies to influence healing (Kerekes & Tronstad 1979, Sjogren et al.1990, Saunders et al.1997).
Suitable statistical methods must be found to investigate the simultaneous influence of several potential factors on either the PGFA or gutta-percha extrusion. It is incorrect to analyze each potential factor separately, using a chi-square test (Weiger et al.1998). It was for this reason that multiple linear regression was selected for this study. On the basis of our results, it can be concluded that after warm vertical compaction, the quality of the adaptation of gutta-percha to the wall of the apical root canal varies, and that a sufficient amount of guttapercha present in the apical canal and sufficient heating are essential in achieving a good adaptation in canals of widely varying diameters.

References.

Buchanan LS (1996) The continuous wave of obturation technique: 'centered' condensation of warm gutta-percha in 12 s. Dentistry Today Jan,60-7.
Co!ae KP, Brilliant JD (1975) The effect of serial preparation versus nonserial preparation on tissue removal in the root canal of extracted mandibular human molars. Journal of Endodontics1, 211-4.
Dummer PMH, McGinn JH, Rees DG (1984) The position and topography of the apical canal constriction and apical foramen. International EndodonticJournal17,192-8.
ElDeeb ME (1984) The sealing ability of injection-molded thermoplasticized gutta-percha. Journal of Endodontics 11,84-6.
FogelHM(1995) Microleakage of posts used to restore endodontically treated teeth. Journal of Endodontics 21,376-9.
Gutmann JL, SaundersWP, Saunders EM, Nguyen L (1993) An assessment of the plastic Thermal obturation technique. Part1. Radiographic evaluation of adaptation and placement. International Endodontic Journal 26, 173-8.
Kas› t'a. kova. A,Wu M-K, Wesselink PR (2001) An in vitro experiment on the effect of an attempt to create an 'apical matrix' during root canal preparation on coronal leakage and material extrusion. Oral Surgery Oral Medicine Oral Pathology Oral Radiology Endodontics 91, 462-7.
Kazemi RB, Safavi KE, Spangberg LSW (1993) Dimensional changes of endodontic sealers. Oral Surgery Oral Medicine Oral Pathology 76, 766-71.
Kerekes K, Tronstad L (1977a) Morphometric observations on root canals of human anterior teeth. Journal of Endodontics 3, 24-9.
Kerekes K, Tronstad L (1977b) Morphometric observations on root canals of human premolars. Journal of Endodontics 3, 74-9.
Kerekes K, Tronstad L (1977c) b Journal of Endodontics 3, 114-8.
Kerekes K, Tronstad L (1979) Long-term results of endodontic treatment performed with a standardized technique. Journal of Endodontics 5, 83-90.
Kontakiotis EG, Wu M-K, Wesselink PR (1997) Effect of sealer thickness on long-term sealing ability: a 2-year follow-up study. International Endodontic Journal 30, 307-12.
Littman SH (1977) Evaluation of root canal debridement by use of a radiopaque medium. Journal of Endodontics 3, 135-8.
McComb D, Smith DC (1975) A preliminary scanning electron microscopic study of root canals after endodontic procedures. Journal of Endodontics1, 238-41.
MolanderA, Reit C, DahlenG, KvistT (1998) Microbiological status of root-filled teeth with apical periodontitis. International Endodontic Journal 31, 1-7.
Nair PNR, SjogrenU, Krey G, Kahnberg K-E, Sundqvist G (1990) Intraradicular bacteria and fungi in root-filled asymptomatic human teeth with therapy-resistant periapical lesions: a long-term light and electron microscopic follow-up study. Journal of Endodontics 16 ,580-8.
<rstavikD(1983) Weight loss of endodontic sealers, cements and pastes in water. Scandinavian Journal of Dental Research 91, 316-9.
Peters DD (1986) Two-year in vitro solubility evaluation of four gutta-percha sealer obturation techniques. Journal of Endodontics12, 139- 45.
Ruddle CJ (1994) Three-dimensional obturation: the rationale and application of warm gutta-percha with vertical condensation. In: Cohen S, Burns RC, eds. Pathways of the Pulp, 6th edn. St. Louis: Mosby, pp. 243-7.
SaundersWP, Saunders EM, Sadiq J, Cruickshank E (1997) Technical standard of root canal treatment in an adult Scottish sub-population. British Dental Journal 182, 382-6.
SchilderH(1967) Filling the root canal in three dimensions. Dental Clinics of North America 11,723-35.
Senia ES, Marshall FJ, Rosen S (1971) The solvent action of sodium hypochlorite on pulp tissue of extracted teeth. Oral Surgery Oral Medicine Oral Pathology 31,96-103.
Silver GK, Love RM, Purton DG (1999) Comparison of two vertical condensation obturation techniques: Touch 'n Heat modified and System B. International Endodontic Journal 32, 287-95.
Sjogren U, Hagglund B, Sundqvist G, Wing K (1990) Factors affecting the long-term results of endodontic treatment. Journal of Endodontics 16, 498-504.
Smith RS,Weller RN, Loushine RJ, KimbroughWF (2000) Effect of varying the depth of heat application on the adaptability of gutta-percha during warm vertical compaction. Journal of Endodontics 26, 668-72.
Svec TA, Harrison JW (1977) Chemo mechanical removal of pulpal and dentinal debris with sodium hypochlorite and hydrogen peroxide vs. normal saline solution. Journal of Endodontics 3, 49-53.
Tronstad L, Barnett F, Flax M (1988) Solubility and biocompatibility of calcium hydroxide-containing root canal sealers. Endodontics and Dental Traumatology 4,152-9.
Weiger R, Axmann-Krcmar D, Lost C (1998) Prognosis of conventional root canal treatment reconsidered. Endodontics and Dental Traumatology14,1-9.
West JD, Roane JB (1998) Cleaning and shaping the root canal system. In: Cohen S, Burns RC, eds. Pathways of the Pulp,7th edn. St. Louis: Mosby, pp. 203-57.
Wu M-K, Barkis D, Roris A, Wesselink PR (2002) Does the first file to bind correspond to the diameter of the canal in the apical region? International Endodontic Journal 35, in press.
WuM-K, De GeeAA,Wesselink PR (1997) Leakage of AH26 and Ketac-Endo used with injected warm gutta-percha. Journal of Endodontics 23, 331-4.
Wu M-K, de Schwartz FBC, van der Sluis LWM, Wesselink PR (2001) The quality of root fillings remaining in mandibular incisors after root-end cavity preparation. International Endodontic Journal 34,613-9.
Wu M-K, Fan B, Wesselink PR (2000a) Diminished leakage along root canals filled with gutta-percha without sealer over time: a laboratory study. International Endodontic Journal 33, 121-5.
Wu M-K, Kasta. kova. A,Wesselink PR (2001a) Quality of cold and warm gutta-percha fillings in oval canals in mandibular premolars. International Endodontic Journal 34,485-91.
Wu M-K,Ozok AR, Wesselink PR (2000b) Sealer distribution in root canals obturated by three techniques. International Endodontic Journal 33,340-5.
WuM-K, PehlivanY, Kontakiotis EG, Wesselink PR (1998) Micro leakage along apical root fillings and cemented posts. Journal of Prosthetic Dentistry 79, 264-9.
WuM-K, RorisA ,BarkisD, WesselinkPR (2000c) Prevalence and extent of long oval shape of canals in the apical third. Oral Surgery Oral Medicine Oral Pathology Oral Radiology Endododontics 89,739-43.
Wu M-K,Wesselink PR (1995) Efficacy of three techniques in cleaning the apical portion of curved root canals. Oral Surgery Oral Medicine Oral Pathology Oral Radiology Endododontics 79, 492-6.
WuM-K,Wesselink PR (2001) A primary observation on the preparation and obturation in oval canals. Internationa lEndodontic Journal 34, 137-41.