TITLE: 
Clinical and radiographic assessment of periapical pathology in single versus multivisit root canal treatment: An in vivo study



ABSTRACT.OBJECTIVE:
The objective of the study was to compare and evaluate the clinical and radiographic outcome of single- versus multivisit endodontic treatment in teeth with periapical pathology at the end of 1, 3, and 6 months.

ABSTRACT.MATERIALS AND METHODS:
Sixty single- and multi-rooted teeth indicated for root canal treatment with periapical pathology were included in the study. The teeth were assigned randomly into two groups Group I and Group II (n = 30 each), which were further subdivided into subgroup IA, subgroup IB and subgroup IIA, subgroup IIB (n = 15 each), respectively. Group I was medicated with ApexCal paste and obturated using the standardized protocol in second visit 7–10 days later, whereas Group II was obturated at the first visit. In subgroup IA and subgroup IIA, obturation was done using Apexit Plus sealer, whereas, in subgroup IB and subgroup IIB, AH Plus sealer was used. Patients were recalled at intervals of 1, 3, and 6 months to evaluate teeth for periapical healing.

ABSTRACT.RESULTS:
Kruskal–Wallis and one-way ANOVA test showed no significant difference between Groups I and II, whereas Wilcoxon signed-rank test showed improvement in all the subgroups with highly significant P value (≤0.001).

ABSTRACT.CONCLUSION:
Single-visit root canal treatment can be considered as a viable option for treatment of teeth with periapical pathology.

BODY.INTRODUCTION:
It has been established beyond doubt that periapical lesion is caused by bacteria in the root canal space.[1] Microbiological goal of endodontic treatment of teeth is to reduce the microbial bioburden to levels compatible with periradicular tissue healing and prevent microbial recolonization of the treated canal.[2] This is accomplished by thorough chemomechanical treatment of root canal followed by three-dimensional obturation.[3]
Traditionally, root canal treatment was performed in multiple visits, with medication between root canal preparation and obturation, which mainly aims to reduce or eliminate microorganisms and their by-products from the root canal system before obturation. Multiple visit root canal treatment is well accepted as a safe and common therapy.[1]
However, in recent years, there is a growing concern about the necessity of multiple appointments in endodontic treatment because no significant differences in antimicrobial efficacies have been reported between the single and multiple visit treatments.[4] Single-visit root canal treatment has become common practice and offers several advantages such as a reduced flare-up rate, good patient acceptance, and practice management considerations.[1] It is believed to eliminate the remaining microorganisms or to render them harmless by entombing them by complete obturation immediately after preparing and irrigating the canal space at the same visit.[5]
Despite the fact that various practices are widely adopted, it does not indicate that the practices are biologically sound and/or appropriate. The argument for single-visit treatment relies heavily on convenience, patient acceptance, and reduced postoperative pain. The issue is very controversial, and opinions vary greatly as to the relative risks and benefits of single versus multiple visit root canal treatment. The direct evidence comparing healing rates following single and multiple visit root canal treatment should provide insight as to which regimen is more effective.[6]
The purpose of the present study is to compare and evaluate the clinical symptoms and radiographic evidence of periapical healing after root canal therapy of teeth with periapical pathology completed in single and multiple visits.

BODY.MATERIALS AND METHODS:
This study was conducted on sixty single- and multi-rooted teeth indicated for root canal treatment. Approval for the scientific research on human subjects was obtained from the Institutional Ethical Committee. Definite guidelines were set for all the patients. Only those who fulfilled the inclusion criteria were included in this study. All patients were informed about the aims and design of the study, and written consent was obtained before their inclusion. The primary inclusion criteria included patients aged above 18 years, single and multi-rooted teeth with radiographic evidence of periapical pathology (periapical index score [PAI] ≥3).
The exclusion criteria included patients with any systemic diseases, pregnant patients, patients who had been taking antibiotics, nonsteroidal antiinflammatory drugs, or corticosteroids before time of treatment, patients who need antibiotic premedication for dental treatment, if the tooth had been previously accessed, grossly decayed teeth, teeth with calcified canals, weeping canals, and teeth requiring re-treatment.
Detailed history and thorough clinical examination were done before starting the treatment. Preoperative intraoral periapical radiograph was taken using a paralleling kit (Flow Dental, New York) before proceeding with actual procedure. The procedure was started with rubber dam isolation, caries excavation, if present, followed by access cavity preparation under 2% lignocaine hydrochloride (Cadila Pharmaceuticals Ltd., India) with 1:200,000 adrenaline. The pulp was extirpated, and a glide path was made using 10 and 15 no. K files (Mani Inc., Japan). Working length determination was done using Apex ID apex locator (SybronEndo, Orange, CA, USA) and confirmed using radiovisiography. The patients were divided into two groups:
BODY.GROUP I:
Group I consisted of thirty single- or multi-rooted teeth which were treated in multiple visits following a standardized protocol. It was further subdivided into two subgroups.
BODY.SUBGROUP IA:
In this subgroup, cleaning and shaping was carried out using HERO Shaper file system (Micro-mega, Besancon, France) in crown down manner. Copious irrigation was done with saline, 3% sodium hypochlorite (DentPro, India), and 2% chlorhexidine (Dentochlor, Ammdent, India) during and after instrumentation with canal prep (Ammdent, India) used as a lubricant. ApexCal medicament (Ivoclar-Vivadent, Schaan, Liechtenstein) was used into the root canal and temporarily restored with Cavitemp (Ammdent, India) and scheduled for a second visit 7–10 days later. At the second appointment, ApexCal was removed with copious irrigation. Corresponding 4% master cone radiograph was taken before obturation to confirm that it was at the correct working length. Canals were dried with paper points and obturated with gutta-percha cones (META Biomed Co., Ltd., Korea) and Apexit Plus (Ivoclar-Vivadent, Schaan, Liechtenstein) as a sealer, using lateral compaction technique. Access cavity was sealed using direct composite restoration, and immediate postobturation intraoral periapical radiograph was taken.

BODY.SUBGROUP IB:
In this subgroup, cleaning and shaping was done in the same manner as that of subgroup IA, but obturation was done using AH Plus (Dentsply Maillefer, Ballaigues, Switzerland) root canal sealer.


BODY.GROUP II:
Another thirty single- or multi-rooted teeth were treated in one visit. It was further divided into two subgroups.
BODY.SUBGROUP IIA:
In this subgroup, cleaning and shaping was done in the same manner as that of subgroup IA. However, after cleaning and shaping, canals were dried with paper points and obturated at the same appointment with gutta-percha cones with Apexit Plus sealer in similar method and materials used for subgroup IA. An immediate postobturation intraoral periapical radiograph was taken after permanent restoration.

BODY.SUBGROUP IIB:
In this group, cleaning and shaping was done in the same manner as that of subgroup IIA, but obturation was done using AH Plus sealer.
A preoperative, immediate postoperative, and recall intraoral periapical radiographs were taken using the standardized paralleling technique with the help of paralleling kit.
Patients were recalled at intervals of 1, 3, and 6 months to evaluate the treated teeth both clinically and radiographically. Clinical assessment included the presence of clinical signs and symptoms (spontaneous pain, presence of sinus tract, swelling, mobility, periodontal probing depths greater than baseline measurements, or sensitivity to percussion or palpation) at each follow-up visit. Radiographic evaluation was done using the PAI scoring system given by Orstavik in 1986.[7]
PAI score description of radiographic findings:

Normal periapical structures
Small changes in bone structures
Changes in bone structure with mineral loss
Periodontitis with well-defined radiolucent area
Severe periodontitis with exacerbating features.





BODY.RESULTS:
In the present study, sixty teeth were examined at 1-, 3-, and 6-month follow-up, thirty in Group I, further subdivided into subgroup IA and IB with 15 teeth each and thirty in Group II, further subdivided into subgroup IIA and IIB with 15 teeth each. Results were evaluated and tabulated.
Clinical signs and symptoms at 1-, 3-, and 6-month follow-up examination were recorded and compared with preoperative records but not subjected to statistical analysis. Since clinical symptoms were rare during the follow-up period. Thus, the outcome was classified mainly on the radiographic evaluation using PAI scoring system.
When scores obtained by radiographic evaluation were submitted to Kruskal–Wallis test, there was no statistically significant difference in periapical healing between teeth in subgroups IA, IB, IIA, and IIB at the baseline, 1-, 3-, or 6-month evaluation with P = 0.342, 0.839, 0.218, and 0.780, respectively.
Results when evaluated by one-way ANOVA test revealed no significant difference between periapical healing of different subgroups from preoperative periapical status to immediate postoperative, 1-, 3-, and 6-month follow-up with P = 0.104, 0.368, 0.672, and 0.317, respectively [Table 1 and Graph 1].
Table 1Comparison of mean periapical index scores between Group I and Group II
Graph 1Mean of change in periapical index score from pre- to postoperative follow. up conditions in all four subgroups indicating periapical healing
Even though results when rendered to Wilcoxon signed-rank test showed no statistically significant difference between four subgroups, the decrease in mean PAI scores showed improvement in all the subgroups, with highly significant P ≤ 0.001 [Table 2].
Table 2Comparison of periapical healing on different intervals within the same groupsc

BODY.DISCUSSION:
The main objective for root canal treatment is to prevent or heal endodontic diseases such as apical periodontitis and to minimize patient discomfort. The basic biologic rationale for achieving ultimate success with root canal treatment consists primarily of eliminating microorganisms from the entire root canal system and creating an environment that is most favorable for healing.[8] Mechanical instrumentation and irrigation with antibacterial solutions have been considered essential for the elimination of bacteria during endodontic treatment, whereas the need for intracanal dressings has been questioned.[3]
Only teeth with definite periapical lesions were included in the study making the comparison between treatment protocols viable. The expectation that teeth treated in two visits with an interappointment dressing would result in improved healing when compared with one-visit root canal therapy was not supported by this study. No statistically significant differences were found between the two treatment groups in the healing of periapical pathology. The findings of this study were consistent with the majority of well-controlled clinical studies.[59101112] When comparison was done between initial and final PAI score in each group, statistically significant improvement in PAI score was found in every group, which corroborates the study of Gesi et al. that with the proper use of aseptic operating procedures, proper instrumentation, and filling, an interappointment dressing with calcium hydroxide does not seem to influence outcome.[13]
Successful endodontic therapy depends on many factors. One such important step in any endodontic treatment is obturation. The obturation requires the use of materials and techniques capable of densely filling the entire root canal system and providing a fluid tight seal from the apical segment of the canal to the cavosurface margin to prevent reinfection. A hermetic seal cannot be achieved with gutta-percha alone; hence, a root canal sealer is essential.[14] In this study, root canals were filled with AH Plus (Dentsply Maillefer, Ballaigues, Switzerland) and Apexit Plus sealer (Ivoclar-Vivadent, Schaan, Liechtenstein). However, no statistically significant relationship was found between the type of sealer used (Apexit Plus and AH Plus) and the healing of periradicular tissue, whether used during multiple or single-visit root canal treatment. These results were comparable with the findings of earlier studies done by Leonardo et al., Waltimo et al., and Tanomaru-Filho et al., who concluded that sealers had a statistically insignificant association to the rapid healing of apical periodontitis.[151617]
Single-visit treatment has many potential advantages. It is less expensive, very well accepted by patients, has shown to result in a lower flare-up rates and similar periapical healing as that in case of multivisit root canal treatment. The findings of our study are also in accordance with the studies of Weiger et al., Sathorn et al., and Su et al. which showed that single-visit root canal treatment appeared to be slightly more effective than multiple visits. However, the difference in healing rate between these two treatment regimens was not statistically significant.[4618]
These results are in contradiction with earlier studies by Sjögren et al. and Katebzadeh et al. which emphasized that the objective of completely eliminating bacteria from the root canal system before obturation cannot be reliably achieved in a one-visit treatment because it is not possible to eradicate all infections from the root canal without the support of an interappointment antimicrobial dressing and that the Ca(OH)2 treatment was statistically superior to one-step treatment.[819] The above results may be attributed to the difference in the sampling of patients, designs of the studies, and treatment procedures.
The findings of our study give support to the assertion that no statistically significant differences occurred between single- and multivisit endodontic procedures when treating teeth with periapical rarefactions regardless of the technique used. The healing potential is within anticipated and acceptable levels when single visit is compared with multivisit cases. Based on clinical and radiographic outcomes of this study, it can be summarized that no additional benefit is provided by the use of an interappointment antibacterial dressing such as calcium hydroxide. Probably, elimination of bacteria is not strictly necessary and maximum reduction of bacteria, and effective canal filling may be sufficient in terms of healing, rather than complete eradication.

BODY.CONCLUSION:
Our study concludes that multiple and single-visit root canal treatment demonstrated almost equal success in endodontic treatment of teeth with periapical pathology. However, long-term follow-up and big sample size are required to further corroborate the findings of this study.
BODY.FINANCIAL SUPPORT AND SPONSORSHIP:
Nil.

BODY.CONFLICTS OF INTEREST:
There are no conflicts of interest.

Question: Compared to Group II was obturated at the first visit. subgroup IB and subgroup IIB, AH Plus sealer was used what was the result of Group I was medicated with ApexCal paste and obturated using the standardized protocol in second visit 7–10 days later. subgroup IA and subgroup IIA, obturation was done using Apexit Plus sealer on periapical healing evaluated by Kruskal–Wallis test?
Evidence: When scores obtained by radiographic evaluation were submitted to Kruskal–Wallis test, there was no statistically significant difference in periapical healing between teeth in subgroups IA, IB, IIA, and IIB at the baseline, 1-, 3-, or 6-month evaluation with P = 0.342, 0.839, 0.218, and 0.780, respectively
Answer: no significant difference