Calcium Hydroxide in Simulated Lateral Canal Filling

atomic cast 20 Hydroxide in Simulated Lateral Canal FillingAim The aim of this turn over was to investigate the influence of calcium hydroxide fertilization on the pick of off-key asquint renders by contrasting obturation proficiencys. Materials and Methods Sixty undivided decide premolars were instrumented. Simulated askant epithelial ducts were class perioded on each third of the stalks. The odontiasis were divided into four groups no get dressed and obturation by lateral ejector seat technique (G1), back with calcium hydroxide and obturation by lateral compressing technique (G2), no dressing and obturation by hybridisation technique (G3) and, dressing with calcium hydroxide and obturation by hybrid technique (G4). The dentition were maintained at 37oC in 100% humidity for seven days, and obturation techniques were performed. Radiographs were taken and lateral renders filled or unfilled were counted. Data were canvas using ANOVA followed by Tukeys test (=5 %). Results The hybrid technique filled macro number of lateral television channels compared to lateral condensation technique, regardless the use of intracanal practice of medicine (PPPConclusion careless(predicate) the obturation technique, calcium hydroxide dressing reduced the brainstorm of filling material in phony lateral canals. Clinical importation The industry of calcium hydroxide residues reduces the penetration of filling material in simulated lateral canals, by chance representing a potential cause of stroke in the future.Keywords Calcium hydroxide, Endodontics, pedigree canal obturation, laboratory look intoIntroductionThe root canal system has a very complex anatomy, characterized mainly by the armorial bearing of curvatures, accessory and lateral canals.1-3 The lateral canals can be observed anywhere along the root continuance of an important percentage of teeth, although more commonly in the top(prenominal) third.1 Actually, the presence of lateral can als represents a challenge, as they are difficult to reach, clean, disinfect and fill during endodontic treatment,4 representing a potential cause of diseases.3,5-8Considering that persisting bacterium may be located in not accessed areas like lateral canals, the intracanal medication and three-dimensional obturation of the root system becomes extremely important.4 The intracanal medication has been utilise to complete the disinfection and to prevent reinfection by these microorganisms,9-11 and can act chemically by killing microorganisms or physically by preventing bacterial penetration.12 The obturation also could prevent reinfection13 as the sealant isolates microorganisms without access to space and nutrients.14Calcium hydroxide has been widely used as an intracanal medication for its antibacterial strength on most of the microorganisms identified in the root canal system.12 The therapeutic properties of this medication are associated with their pH value and with the period that they remain within the root canals.9,15 It has been pointed out that calcium hydroxide dressing for seven days with subsequent instrumentation and irrigation with sodium hypochlorite, improve the debridement of the root canal system and efficiently pop off persistent bacteria.16,17 However, it was install that a considerable amount of calcium hydroxide paste remains disposed to the root canal after instrumentation and irrigation with various solutions.18-20 Also, it is known that when calcium hydroxide is incompletely aloof from the root canal, the residue compromises the endodontic sealing.20,21 Thus, it is possible that residual calcium hydroxide could obliterate the openings of the lateral canals, occlude their filling.19,22 Additionally, the type of obturation technique is a crucial factor to be considered in such situations, since the cap great power to assure the filling of lateral canals is an important clinical parameter and may represent a favorable feel of the filling technique.In this context, the aim of this in vitro study was to evaluate the influence of calcium hydroxide dressing on the filling of simulated lateral canals by different obturation techniques.Materials and MethodsThe study has been approved by an honorable committee from Pontifcia Universidade Catlica do Paran, under number of register 326/2004. all one researcher has do the experimental procedures.Sample preparationIn this in vitro study, a total of sixty human single root mandibular premolars with medium length among 21 to 23 mm were selected. The teeth were autoclaved and stored in 0.5% thymol solution prior to the experimental assays. The coronal access was gained with a 2 round and a 3080 diamond bur (KG Sorensen, Barueri, SP, Brazil). Then, the coronal and middle thirds of the root canal were shaped using 1, 2, and 3 Gates-Glidden drills (Dentsply Maillefer, Ballaigues, Switzerland). The canal length was visually established by placing a 10 K- commove (Dentsply M aillefer, Ballaigues, Switzerland) in each root canal until it was seen emerging through with(predicate) the apical foramen. The working length was determined by subtracting 1 mm from this measurement. The teeth were instrumented at the working length using a 35 K-File (Dentsply Maillefer, Ballaigues, Switzerland).Simulated lateral canalsThree simulated lateral canals were drilled on the mesial and distal surfaces (one in each third coronal, middle and apical) by using a device. This device consisted by a 10 K-File (Dentsply Maillefer, Ballaigues, Switzerland) with 4 mm from its tip sectioned, which was accommodate in a low-speed contra-angle handpiece. The root canals were then instrumented using a 45 K-File (Dentsply Maillefer, Ballaigues, Switzerland) to the working length to acquire a smear layer. After every change of file size and at the completion of instrumentation, the canals were irrigated with 5 mL of a 1% sodium hypochlorite solution. Following this, the root canal wa s irrigated with 5 mL of 17% ethylene diaminetetraacetic acid (EDTA) (Merck Brasil, So Paulo, SP, Brazil) followed by a final flush of distilled water. The root canals were dry out with paper points (Tanariman Manufacturer, Amazonas, AM, Brazil).Experimental groupsAfterwards, the sixty teeth were randomly divided into four equal groups of fifteen. The groups were separated match to the use or not of calcium hydroxide dressing, and the type of obturation technique, as follow no dressing and obturation by lateral condensation technique (G1), dressing with calcium hydroxide and obturation by lateral condensation (G2), no dressing and obturation by Taggers hybrid technique (G3) and, dressing with calcium hydroxide and obturation by Taggers hybrid technique (G4).Dressing procedureIn G2 and G4, the calcium hydroxide paste was brisk by mixing two parts of lab grade calcium hydroxide and 1 mL saline solution to obtain a creamy consistency. The paste was inserted using a 25 Lentulo drill (Dentsply Maillefer, Ballaigues, Switzerland), subtracting 2 mm from the working length. The access cavities were temporarily sealed with a cotton pellet and unstable seal (Coltosol, Coletene, Rio de Janeiro, RJ, Brazil). The samples were maintained at 37oC in 100% humidity for seven days. Afterwards, the temporary seal was distant and the calcium hydroxide was cleaned using a 35 K-File (Dentsply Maillefer, Ballaigues, Switzerland) and irrigation with 1% sodium hypochlorite solution and 17% EDTA (Merck Brasil, So Paulo, SP, Brazil). The root canals were dried with paper points (Tanariman Manufacturer, Amazonas, AM, Brazil).Obturation techniquesFor obturation procedures, the AH Plus sealer (Dentsply Maillefer, Ballaigues, Switzerland) was used in all groups. The sealer was manipulated according with manufacturers instructions. The obturation technique was performed as follow.Lateral condensationFor G1 and G2, it was used the lateral condensation technique. For this, a well-fitting master gutta-percha cone 35 (Dentsply Maillefer, Ballaigues, Switzerland) coated with sealer was taken up 1 mm from the working length. Then, the master cone was left seated and the lateral condensation was performed using a finger spreader B (Dentsply Maillefer, Ballaigues, Switzerland). This spreader was inserted with the sealer toward the canals wall and then counterclock wisely distant to create room for the insertion of the accessory gutta-percha cones (Dentsply Maillefer, Ballaigues, Switzerland). This procedure was repeated until the insertion of new accessory cones was not possible. After the obturation completion, the excess of filling material was removed and the cool vertical condensation was executed.Taggers hybrid techniqueFor G3 and G4, it was used the Taggers hybrid technique. For this, a master cone was seated as describe above. An initial lateral condensation was performed with the finger spreader B (Dentsply Maillefer, Ballaigues, Switzerland), and one accessory gutta-percha cone was inserted. Next, a McSpadden compactor 70 (Dentsply Maillefer, Ballaigues, Switzerland) was coupled to a low-speed contra-angle handpiece and introduced passively into the root canal. The penetration of the condenser within root canal was obtained with the aid of a rubber marker 1 mm short of the working length. With the condenser inside the root canal, next to the gutta-percha cones, it was driven by forward and backward movements up to reach working length, staying in that position for about 1 second. The condenser was removed from root canal with the motor still driven with gentle pressure on one side of the canals wall. Following, the vertical condensation of the plasticized gutta-percha was performed through heat Paivas condensers in order to obtain a better adaptation of the filling material. surgical radiographsImmediately after filling, postoperative radiographs were taken and all of them were identically exposed, developed, and fixed. The radiographs were placed in slide mounts and project in order to count the lateral canals filled or unfilled in each group. Only completely filled lateral canals were considered. Three calibrated testers analyzed the images.Statistical analysisData were statistically analyzed by the SAS/LAB package (SAS Software, version 9.0 SAS Institute Inc., Cary, USA). Firstly, Kappas test was performed to evaluate the examiners level of agreement.The assumptions of equality of variances and normal distribution of errors were checked and the data were transformed as suggested by the software. The simulated lateral canals were analyzed using three-way ANOVA followed by Tukey HSD test, considering the dressing, obturation technique and root thirds as study factors. The significance level was set at 5%.ResultsThe value of the test of agreement between examiners was 0.89.In Figure 1, it is observed representative radiographs after obturation by different techniques.The Taggers hybrid technique filled large numb er of simulated lateral canals compared to the lateral condensation technique, regardless the use of intracanal medication (PPAlthough the coronal and apical thirds had a somewhat larger number of filled lateral canals than the middle third, this remnant was not statistically significant (P0.05) (Table 1). Significant differences were observed when comparing the number of filled and unfilled canals in the same root third of each group (PP0.05).DiscussionAfter shaping and cleaning the root canal, persisting bacteria may be located in not accessed areas like lateral canals, and this must(prenominal) be considered potentially pathogenic and a cause of future endodontic failure.3,5-8 For this reason, dressing and three-dimensional obturation of the root canal system becomes important steps.4The use of calcium hydroxide dressing is established in the literature,23 however, persistence of this medication in the root canal walls could prevent the sealer penetration into the dentinal tubu les,21 compromising the obturation procedure. Also, several techniques need been developed to achieve an adequate three-dimensional obturation of lateral canals.24 For this, we purposed to evaluate the influence of calcium hydroxide dressing on the filling of simulated lateral canals by different obturation techniques.The actual need to fill lateral canals has been a largely discussed in the current literature.2,4,19 However, it is important to point out that both lateral canals and apical ramifications have been implicated with treatment failure when they are sufciently large to harbor signicant numbers of bacteria and to provide these bacteria with access to the periradicular tissues.3,25 Therefore, disinfection, dressing and filling of lateral canals in cases of pulp necrosis and apical and/or lateral periodontitis should be considered important goals of the treatment, although difcult to achieve.3Calcium hydroxide is widely used as an intracanal medication,12 and several techni ques have been used to remove it from the root canal.18,21,26,27 The enlargement of the canal to the next file size and copious irrigation with sodium hypochlorite and/or EDTA, which are the procedures commonly used in clinical practice, seems to be unable in completely remove calcium hydroxide from root canal.21,26 There is a consensus that the residues of the medicament persists in the canal even with different techniques for removal.28,29The results of our study demonstrated that residual calcium hydroxide barricade the openings of the lateral canals, reducing and/or preventing the penetration of sealer or gutta-percha into the lateral canals, corroborating with a previous study.19 Regardless the obturation technique, we demonstrated that when calcium hydroxide was applied as a dressing medication (G2 + G4), 99 of the one hundred eighty simulated lateral canals were obturated. On the other hand, when calcium hydroxide was not used (G1 + G3), 129 of the 180 simulated lateral cana ls were filled. Also, in our study, simulated lateral canals were created in each third of the canal root. We showed that no differences were found among the different root thirds in the same group. About the ability of different obturation techniques to fill simulated lateral canals the literature indicates that warm gutta-percha techniques are superior.2According to our results, the Taggers hybrid technique resulted in large number of filled simulated lateral canals, although it was reduced with the dressing with calcium hydroxide. Also, the lateral condensation showed the worst ability in filling simulated lateral canals, particularly when calcium hydroxide dressing was employed. It is possible that the cold condensation of gutta-percha difficult the penetration of the filling material.30 Thermoplasticized techniques improve the expansion of the material against the dentinal walls.31A recent study about the interference of calcium hydroxide previous to the filling revealed that t he medication can difficult the tight filling of the root canal system because of its property of obliterates lateral canals.22Overall, the persistence of calcium hydroxide residues should be considered as a side effect when selecting this medication as an interappointment dressing in root canal therapy,19,22 regardless the obturation technique to be employed.ConclusionsRegardless the obturation technique, calcium hydroxide dressing reduced the penetration of filling material in simulated lateral canals.Clinical significanceThe persistence of calcium hydroxide residues reduces the penetration of filling material in simulated lateral canals, possibly representing a potential cause of failure in the future.1