Relationship between post-preparation pain and apical patency: A randomized clinical trial

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1 Relationship between post-preparation pain and apical patency: A randomized clinical trial Marwa E Sharaan 1*, Naguib M Aboul-Enein 2 1 College of Dentistry, Gulf Medical University, Ajman, UAE 2 Department of Endodontics, Faculty of Dentistry, Suez Canal University, Egypt *Presenting Author ABSTRACT Objective: This study was conducted to compare the post-preparation pain experience following root canal preparation with or without achieving and maintaining apical patency during root canal preparation. Materials and Methods: Root canal preparation was completed in the first visit for eighty patients. The patients were divided randomly into two groups where patency was either established and maintained during preparation or not. Pain was recorded before treatment, 6,12,18,24 and 48 hours after treatment. Patients assessed their severity of pain over the first two days following root canal preparation using a modified visual analog scale of (0-9). Results: Our results showed that no significant difference was found between the two groups. No significant difference was found between the two groups studied. No significance was found between all the previous preoperative clinical and radiographic findings and post-preparation pain, except preoperative pain. Conclusion: Apical patency did not increase the post preparation pain significantly Key words: post-preparation pain, apical patency. INTRODUCTION Postoperative pain after endodontic procedures is a frustrating occurrence for both patients and clinicians. Endodontic pain may occur before, during, or after endodontic treatment 1. During root canal instrumentation, dentinal and pulpal debris can block access to the apical third, increasing the possibility of transportation or perforation which may lead to postpreparation pain 2,3,4. Many researchers pointed out that apical blockage could be avoided by using patency file 5. Maintaining apical patency improved the delivery of irrigants into the apical third of large human root canals 6,7. Canal patency is performed by pushing small highly flexible files passively through apical constriction without widening it. Considering the rich collateral circulation and healing potential of the attachment apparatus, establishing and maintaining patency are non-harmful biological events 8. On the contrary, some clinicians suggested that repeated use of small patency files could push apical debris. They accused it by its responsibility for acute periapical inflammatory response and as a result, severe post operative pain 9,10. The concept of creating and maintaining canal patency is still controversial. The aim of this study was to evaluate whether establishing and maintaining apical patency would influence the incidence, degree or duration of postoperative pain. We did not find any published research assessing the incidence of postpreparation pain when apical patency was maintained during preparation. One recent research, Arias et al, studied the effect of apical patency on postoperative pain after obturation 3. MATERIALS AND METHODS A total of eighty patients consented to participate in this study at the clinic of endodontics, Faculty of Dentistry, Suez Canal University. Patients of both sexes ranging from 14 to 60 years of age were selected. All teeth were permanent with mature apices. Patients received initial nonsurgical root canal therapy on a single tooth over two visits. Symptomatic and asymptomatic anterior and posterior 96 GMJ, 4 th Annual Scientific Meeting of Gulf Medical University Oral Proceedings 2012

2 teeth with pulpal and / or periapical pathosis were included in the study. The patients did not take any medications that could affect pain perception or inflammation. The patients were assigned randomly into two groups (40 per group). Apical patency was established and maintained during preparation in one group while it was not undertaken in the other. The working length of root canals were determined electronically by using the ipex apex locator (K Japan) and confirmed radiographically ( 0.5-1mm). In Group I, patency stainless steel k- file # 10 was moved 1 mm through the apical foramen during the root canal preparation after each file. In Group II apical patency was neither established nor maintained during preparation. The root canals were instrumented using a combination of passive step-back technique with hand instruments and crown down technique using hero shaper (Micromega France) nickel titanium rotary instruments. The root canals were prepared to an apical ISO that ranged from size #35 to # 55 (master apical file) depending on both root canal anatomy and initial diameter of root canal. Irrigation was continuously performed passively using 2ml of 2.25 % sodium hypochlorite (NaOCl) solution between each file. Rc-prep paste (Premier USA) was used. All root canals were later dried with sterile paper points. After placing a dry sterile cotton pellet in the pulp chamber of each tooth, the access cavities were sealed with 4 mm Cavit )Espe Switzerland) as a temporary filling. Pain as experienced by the patients following the endodontic therapy was scored and recorded in a home report. Patients recorded pain score before treatment and 6, 12,18,24 and 48 hours after treatment. The patients assessed their severity of pain using a modified visual analogue scale (VAS). The degree of pain recorded at each period of observation was given a numerical value (0= no pain, 1-3= mild pain, 4-6= moderate pain, 7-9= severe pain). Two days after cleaning and shaping, the patients returned for obturation of their root canals bringing their completed questionnaires. All cases were obturated using lateral compaction technique. RESULTS Preoperative clinical and radiographic findings were recorded for two groups before treatment. These conditions were: preoperative pain, percussion/palpation Table 1. Correlation between clinical and radiographic findings and the post-preparation pain Clincal & Radiographic findings Min. -Max. Mean ± SD P valve Preoperative pain No ± 1.53 Yes ± 1.97 Percussion / palpation No ± 1.96 Yes ± 2.01 Swelling No ± 1.95 Yes ± 2.34 Radiographic radiolucency No lesion ± 1.85 Thickening of PDL ± 1.97 Lesion < mm ± 2.24 Lesion > mm Pulpal diagnosis Normal ± 1.73 Irreversible pulpitis ± 1.94 Necrotic pulp ± 2.03 Periradicular diagnosis Normal ± 1.89 Acute apical peridontitis ± 1.92 Chronic apical periodontitis ± 2.24 < 0.01 GMJ,4 th Annual Scientific Meeting of Gulf Medical University Oral Proceedings

3 senstivity, swelling, radiographic radiolucency, pulpal and periradicular status. No significant difference was found between the two groups studied. No significance was found between all the previous preoperative clinical and radiographic findings and postpreparation pain, except preoperative pain. When it existed, there was a higher tendency for post-preparation pain. There was a significant correlation between the presence of post-preparation pain and preoperative pain (p< 0.01) (Table 1). None of the patients developed symptoms of acute inflammation necessiating removal from the study. After 48 hrs. of root canal preparation of the patients, 44 % had no post-preparation pain, 41 % had mild pain, 14 % had moderate pain and 1 % had severe pain (Table 2). Table 2. Number of patients who experienced different degree of post-preparation pain in two groups after 48 hrs. of observation Pain degree No. % None Mild Moderate Severe 1 1 Total Post-preparation pain decreased with time in both groups tested. Although it was statistically insignificant, it was found that in group I, there was a tendency for an increase in post-preparation pain at 6 and 12 hrs. as compared to group II. On the other hand, there was a tendency of a decline in post-preparation pain at 24 and 48 hrs. in group I when compared to group II, with no significant difference (Table 3). DISCUSSION Post-preparation pain during root canal treatment was the focus of interest in this study. We aimed to assess the effect of apical patency on post-preparation pain. Endodontic pain was defined as pain of any degree that occurs after the initiation of root canal treatment 1. Clem defined postoperative pain as a pain existing in a patient who had previously experienced none as an increase in an already existing pain 12. Pain is an individual matter and dificullt to be measured accurately. Pain could be measured only according to the patient response 13. No pain research would be complete without addressing the subjectivity of the pain response. It is Table 3. Comparison between group I and group II at the different time intervals Variables Group I Group II P Pre-operative Min.-Max Mean ± SD 4.45 ± ± 2.54 Post 6hrs Min.-Max Mean ± SD 3.73 ± ± 2.67 Post 12hrs Min.-Max Mean ± SD 3.15 ± ± 2.54 Post 18hrs Min.-Max Mean ± SD 2.38 ± ± 2.26 Post 24hrs Min.-Max Mean ± SD 1.80 ± ± 1.95 Post 48hrs Min.-Max Mean ± SD 1.00 ± ± GMJ, 4 th Annual Scientific Meeting of Gulf Medical University Oral Proceedings 2012

4 a difficult concept to qualify or quantify the pain in any statistical analysis. Pain research was an area where subjective information is crucial and the questions to be answered are more complex or dependent on the patient s integration of the object (pain) and the response (action or impact) 14. In this study, preoperative clinical and radiographic findings as well as pulpal and periradicular diagnoses were collected from all patients. No significant difference in the distribution was found between two groups. These factors included perscussion / palpation senstivity, preoperative swelling, vitality of teeth, presence of periapical radiolucencies and apical periodontitis either chronic or acute. The contribution of these factors to the post-preparation pain revealed insignificant influence on the development of post-preparation pain. These findings were in agreement with those of other investigators However, some authors reported the significant effect of these factors on the development of interappointment pain. The factors included age, gender, tooth type, pulpal status, presence of preoperative pain, preoperative periapical diagnosis, size of periradicular lesions, allergies and presence of sinus tracts 15, In this investigation, the presence of preoperative pain was found to be the only significant factor influencing the incidence of post-preparation pain. This finding was in accordance with that in other studies 20,21,23,24, On the other hand, other investigations negated the association between the presence of preoperative pain and the incidence of postpreparation pain 19,25,26. In the current study, data revealed a decline in mean pain intensity over time for both groups after endodontic treatment. These findings were similar to those of other clinical studies that demonstrated a significant reduction in pain after root canal treatment 15,20,21,23. Negm explained the decrease in postoperative pain level could be a function of pain resolution with healing 1. Endodontic treatment by itself often provided pain relief 30. The decrease in pain might be due to a reduction in tissue levels of inflammatory mediators and interstitial tissue pressure that stimulate peripheral terminals of nociceptors 32. In the present study,it was found that pain persisted at different levels. The occurrence of post-preparation pain of mild intensity was not a rare event even when endodontic treatment had followed acceptable standards 16,18,21. The development of post-preparation pain of moderate to severe intensity has been demonstarted to be of unusal occurrence 34. In this study, the prevalence of 45% pain experience after 48 hrs. of root canal preparation was much higher than that reported in some studies 16,18,21 whereas it was lower compared to some others 13,24,27. This discrepancy could be attributed to differences in the preoperative status of the teeth and the treatment procedures. In the current study, the results showed that preparation of the apical foramen with patency had a decreased mean pain level at most of the time intervals. Preparation shorter of the apical foramen might leave a dentinal plug full of necrotic debris and bacteria which might cause inflammation and delayed healing. This plug could cause an increase in pain incidence especially when there was an apical inflammation with its subsequent pressure Using a patency file might remove the remaining debris, keeping the foramen free from any blocked infected debris, assuring a clean foramen 4,11,38. Furthermore, it could give the chance of venting in such cases of apical inflammation resulting in pain decline. The findings of the present study are in accordance with those others who emphasized the use of apical patency concept. Flanders stated that unless apical patency was established and maintained throughout the cleaning and shaping procedures, a portion of the root canal system was likley to be left untreated, inviting failure 38. The use of smaller files which maintained a limited apical opening reduces the extrusion of noxious material to the surrounding GMJ,4 th Annual Scientific Meeting of Gulf Medical University Oral Proceedings

5 tissue 4,11,39. It was also claimed that the amount of smear layer could be reduced by using patency files 9. Moreover, researchers reported the accessbility of instruments to apical constriction of root canals was closely related to treatment outcome. The success rate was lower in the group of cases with inaccessible apical constriction than where the canals had accessible constriction 40. Furthermore, in a recent study Sanchez at al. reported a well prepared apical foramen without any transportation using apical patency 41. On the contrary, others stated that apical patency encourged the extrusion of dentin chips, debris and irrigants and caused overenlargement of the apical foramen leading to periapical tissues damage 17,42,43. The periapical healing process of teeth in dogs with or without apical patency and after root filling was assessed in a study by Holland et al. 43 Signifcantly better healing was found in the group in which patency was not maintained. It should be noted that using large instruments at the patency length could result in severe periradicular injury, causing lack of apical stop and extrusion of a large amount of infected debris, which predisposed to the occurrence of postpreparation discomfort and /or jeopardized the outcome of endodontic therapy 10,44. A scanning electron microscope investigation showed cementum fractues and dentinal chips at the apex after penetration of a # 15 k-file through the foramen 10. In this study, small files (# 10 K-file) were used gently to guarantee that the canal was only negotiated without any futher apical enlargement. In general, we can say that apical patency did not display any significant influence on the incidence or intensity of postoperative pain. This finding was consistent with that of others who found that apical patency had no effect on the postoperative pain incidence 3,21,22. CONCLUSION Apical patency did not increase the post preparation pain significantly. RECOMMENDATION Comparing the advantages and the disadvanatges of apical patency, we recommend establishing and maintaining apical patency during root canal preparation. REFERENCES 1. Negm M. Intracanal use of a corticosteroid antibiotic compound for the management of post treatment endodontic pain. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92: Al-Omari MA, Dummer PM. Canal blockage and debris extrusion with eight preparation techniques. Journal of Endod 1995; 21: Arias A etal.relationship between postendodontic pain, tooth diagnostic factors, and apical patency. Journal of Endod 2009; 35: Cailleteau JG, Mullaney TP.Prevalence of teaching apical patency and various instrumentation and obturation techniques in United States dental schools. Journal of Endod 1997;23: Cohen S and Burns RC. Pathways of the pulp, eighth ed., copyright, Mosby; 2002: Jorge Vera et al. Effect of Maintaining Apical Patency on Irrigant Penetration into the Apical Third of Root Canals When Using Passive Ultrasonic Irrigation: An In Vivo Study.Journal of Endod 2011 ;37: Jorge Vera et al. Effect of Maintaining Apical Patency on Irrigant Penetration into the Apical Two Millimeters of Large Root Canals: An In Vivo Study, An In Vivo Study, Journal of Endod 2012;38: Buchanan LS. Management of the curved root canal. J Calif Dent Assoc 1989;17: Goldberg F and Massone EJ. Patency file and apical transportation ; an in vitro study. J Endodon 2002;28: Gutiérrez JH, Brizuela C and Villota E. Human teeth with periapical pathosis after overinstrumentation and overfilling of the root canals: a scanning electron microscopic study. International Endodontic Journal 1999;2: Sathorn C, Parashos P and Messer H. The prevalence of postoperative pain and flare up in single and multiple endodontic treatment : a systemic review. Int Endo J 2008;41: Clem WH. Posttreatment endodontic pain. Journal of American Dental association 1970; Harrington J and Natkin E. Mid treatment flare ups. Dental clinics of North America 1992;36: Atchison K. understanding and utilizing qualitative research. Journal of Dental education 1996;60: GMJ, 4 th Annual Scientific Meeting of Gulf Medical University Oral Proceedings 2012

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