Clinical and radiographic evaluation of single-visit and multi-visit endodontic treatment of teeth with periapical pathology: An in vivo study.

OBJECTIVES: To compare and evaluate the clinical symptoms and radiographic evidence of periapical healing after endodontic treatment of teeth with periapical pathology when completed in one-visit or two-visits with ApexCal paste at 3, 6, and 12 months.
MATERIALS AND METHODS: A total of 57 patients requiring root canal treatment on 64 single rooted teeth with periapical pathology preoperatively were included. The teeth were assigned randomly into two groups and treated according to standardized protocol. The teeth in group I (n = 34) were obturated at the first visit, while those in group II (n = 30) were medicated with ApexCal paste, and obturated in a second visit 7 days later. Patients were recalled at intervals of 3, 6, and 12 months to evaluate the treated teeth both clinically and radiographically for periapical healing.
RESULTS: Mann - Whitney U test showed no difference between groups I and II. Wilcoxon signed rank test showed significant decrease in mean periapical index (PAI) scores within both groups during 12 months evaluation. The level of significance used was P < 0.05.
CONCLUSIONS: Both groups exhibited equally favorable healing at 12 months, with no statistically significant differences between groups I and II.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Periapical lesion is caused by bacteria in the root canal space. The most important objective of root canal therapy is to minimize the number of microorganisms in root canal systems.[1]

The scientifically documented procedure was biomechanical preparation of the root canal during the first appointment, followed by the application of a calcium hydroxide dressing for one week or more. Root filling is then performed at the second or a later appointment.[2] However, it has been shown that calcium hydroxide fails to consistently produce sterile root canals and even allows regrowth in some cases.[3]

Another approach is 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.[34]

Many studies reported that one-visit endodontic treatment offers some potential advantages to both clinician and patient. In addition to being faster and very well accepted by patients, it may prevent the risks of root canal system contamination or recontamination between the clinical appointments. There was widespread acceptance of single visit endodontics for vital cases. Nevertheless, treatment in one session of necrotic pulps associated with periradicular lesions remains one of the important dispute in endodontics.[5] Due to these conflicting opinions, the number of visits necessary to treat infected root canals is debated in recent years.

The purpose of the present study was 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-visit or with ApexCal intracanal medication in two-visits.

MATERIALS AND METHODS

Patient selection

Approval for the project was obtained from institutional ethical committee for research on human subjects. All the teeth for treatment were selected based on the following criteria. The primary inclusion criteria includes patients aged between 18 and 62 years, only single rooted teeth with Vertucci's type I canal configuration, teeth with radiographic evidence of periapical pathology (periapical index (PAI) ≥ 3) and pulpal necrosis.

The exclusion criteria includes patients with any systemic diseases, pregnant patients, patients who had been taking antibiotics, nonsteroidal antiinflammatory drugs or corticosteroids prior to time of treatment, patients who needs antibiotic premedication for dental treatment, if the tooth had been previously accessed, grossly decayed teeth where rubber dam isolation is difficult, teeth with calcified canals, and weeping canals.

Oral and written informed consent was obtained from the participants to join the study and understood the need to attend follow up sessions. During the recruitment period, a total of 64 single rooted teeth from 57 patients, 30 male and 27 female, with mean age of 40 years (age range = 18-62) fulfilled the inclusion criteria. Six patients contributed more than one tooth in which five patients with two teeth and one patient with three teeth. A total of 14 patients had to be excluded from the randomization procedure. Five patients were on pain or antibiotic medication, seven patients were refused to participate in the study and two patients were not to be available for recall.

Endodontic treatment

A total of 64 single rooted teeth were selected and randomly divided into two groups to perform root canal therapy. Thirty-four teeth in group I were treated in one visit and 30 teeth in group II in two visits following a standardized protocol.

The procedure for both groups was infiltration of local anesthesia, rubber dam application, caries excavation if present, and access preparation. Working length was checked with root ZX apex locator (J. Morita corporation, Japan) and confirmed by using radiographs. The instrumentation was carried out using Protaper universal files (Dentsply Maillefer, Switzerland) in a crown down manner according to manufacturer's instructions. Copious irrigation was done with 3% sodium hypochlorite (Prime Dental Products, India) and saline by canal clean needle (Ammdent, India) during and after instrumentation. RC-help (Prime Dental Products, India) was used as a lubricant during filing.

After instrumentation, canals were dried with paper points and were obturated at the initial appointment with gutta percha cones (META Biomed Co. Ltd, Korea) and AH plus (Dentsply Maillefer, Switzerland) as a sealer, using lateral condensation technique. Teeth were then restored with glass ionomer cement (GC Gold Label, Japan) and postobturation IOPAR was taken.

For teeth assigned to group II, a paste carrier was used to carry ApexCal (Ivoclor/vivadent, Liechtenstein) medicament into the root canal and temporarily restored with cavit (3M ESPE, USA) and were scheduled for a second visit 7 days later. At the second appointment, the ApexCal was removed and canals were obturated with similar methods and materials used for group I. A postobturation IOPAR was taken.

Radiographic technique

All patients in the study had a standardized X-ray series. Preoperative, immediate postoperative, and recall radiographs were taken with individual bite blocks attached to the beam guiding device, Rinn Xcp holder (Dentsply Maillefer, Switzerland). All radiographic films were exposed and processed conventionally under similar conditions. During the endodontic treatment, working length or master-cone images, when appropriate, were obtained by freehand. The radiographs were then digitalized using Digital X-ray reader (Zhengzhou Smile Dental Equipment Co. Ltd., China).

Follow up

Patients were recalled at intervals of 3, 6, and 12 months to evaluate the treated teeth both clinically and radiographically.

Clinical assessment

Clinical assessment includes presence of clinical signs and symptoms at 12 months (spontaneous pain, presence of sinus tract, swelling, mobility, periodontal probing depths greater than baseline measurements, or sensitivity to percussion or palpation). The patients who had taken medication for any systemic illness during the follow-up period were excluded from the study.

Radiographic assessment

Radiographic evaluation was done using the PAI scoring system given by Orstavik in 1986. This is a 5-point scale radiographic interpretation designed to determine the absence, presence, or transformation of a diseased state. The reference is made up of a set of five radiographs with corresponding line drawings and their associated score on a photographic print.[67]

Table 1 represents the description of PAI scores.

Table 1

Description of Periapical index scores

(adapted from Orstavik et al.[6] and Penesis et al.[7])

Outcome measures

The primary outcome measure for this study was change in apical bone density at 12 months. Secondary outcome measures were the presence of clinical signs and symptoms at 12 months and proportion of teeth in each group that could be considered improved or healed.

RESULTS

In the present study, 44 teeth were examined at the 12-months follow-up, 23 in group I and 21 in group II. There were two treatment failures before the 12-month examination (one in group I and one in group II), and 18 additional teeth were lost to follow-up.

Results were evaluated and tabulated. Clinical signs and symptoms at the 12-months follow-up examination were recorded and compared with preoperative diagnostic records but not subjected to statistical analysis. Mann — Whitney U test showed no statistically significant difference between groups I and II at either the baseline, 3, 6, or 12 months evaluation.

Table 2 represents comparison of mean PAI scores between groups I and II.

Table 2

Comparison of mean PAI scores between Group I and Group II

Within groups I and II, Wilcoxon signed rank test showed statistically significant decrease in the mean PAI scores from baseline to 3, 6, and 12 months follow-up evaluation.

At the end of 12 months, the following results were obtained. In group I, 61% of the teeth could be considered healed, 83% were improved, 39% were not healed, 13% were unchanged, and 4% were worse. In group II, 76% of the teeth could be considered healed, 86% were improved, 24% were not healed, 10% were unchanged, and 5% were worse. The unhealed group consists of both unchanged and worsened lesions. Chi-square test showed no statistically significant difference between groups I and II (P = 0.217).

Table 3 represents proportion of teeth healed, not healed, improved, unchanged, or worse in each group at 12 months evaluation.

Table 3

Proportion of teeth healed, not healed, improved, unchanged, or worse in each group at 12 months evaluation

DISCUSSION

In this study, selected patients were randomly assigned into two treatment groups to avoid bias. In order to eliminate any operator dependent variations in the results, all the teeth were treated by a single operator.

Calcium hydroxide has been widely used as inter appointment dressing because of its proven antibacterial properties, periapical tissue healing stimulation, and capacity to detoxify bacterial lipopolysaccharides.[8910] The vehicle plays a most important role in the overall process because it determines the velocity of ionic dissociation causing the paste to be solubilized and resorbed at various rates by the periapical tissues and from within the root canal. There are various vehicles like aqueous, viscous, and oily. Aqueous vehicles have rapid ionic dissociation and consequently short-term action. Viscous vehicles permits slower liberation of hydroxyl ions, maintaining its action for a longer period, are preferable in teeth with periapical lesions. Oily vehicles may remain within the root canal for very long periods.[1011]

In the present study, Ca(OH)2 paste, which is commercially available as ApexCal, was taken. Polyethylene glycol present in this paste is a viscous vehicle, which maintains Ca(OH)2 action for a longer period. It was used as an intracanal dressing for 7 days in accordance with the study done by Sjogren et al., demonstrated that a 7 day usage of calcium hydroxide medicament was sufficient to reduce canal bacteria to a level that gave a negative culture.[121314] In this study, culture test was not performed in both treatment groups before obturation because culturing canals after the use of an intracanal medicament (especially calcium hydroxide) may largely demonstrate the carryover effect of residual medicament rather than elimination of bacteria from the canal space.[1516]

Although longer observation periods might be ideal, evidence of periapical changes in bone density associated with healing should be apparent at 12 months when using the PAI, and longer observation times might not be necessary.[7813] We intend to perform follow-up evaluation on patients in this study at 3, 6, and 12 months in consistent with the results of earlier studies.

Clinical symptoms were rare during the follow-up period. Thus, the outcome was classified mainly on the radiographic evaluation using PAI.[27]

When scores obtained by radiographic evaluation were submitted to Mann — Whitney U test, there was no statistically significant difference between teeth in groups I and II at either the baseline, 3, 6, or 12 months evaluation. This finding is in consistent with the results of majority of well controlled clinical studies done.[23789171819202122]

These results are in contradiction with earlier studies[152324] where they showed that calcium hydroxide treatment would be statistically superior to one-visit treatment. This could be attributed to difference in the sampling of patients, designs of the studies, and treatment procedures.

Even though Wilcoxon signed rank test showed no statistically significant difference between two groups, the decrease in mean PAI scores showed better improvement in group II than in group I. This might be due to the use of intracanal dressing ApexCal for one week in group II. These results were comparable with the findings of earlier studies done by Trope et al. and Penesis et al.[27]

In the present study, although the percentage of healed teeth were more in group II than in group I. Chi-square test showed no significant difference between the two groups, could be due to the small sample size.

The findings of current study clearly demonstrate that mechanical instrumentation, chemical disinfection, and obturation plays an important role in healing of periapical lesions. In the present investigation, the size of the periapical lesion was proven to be a risk factor. That means that a larger periapical lesion was associated with a lower probability to resolve within a given period of time than a smaller lesion.

The insignificant results between the two groups in this study may be due to true observed insignificant difference or because of the low sample size. Properly designed randomized clinical trials are needed to further explore the results. The basic demographic characteristics of the two study groups were similar, and neither group varied significantly from the study dropouts.

CONCLUSION

Within the limitations of this study, there was no statistically significant difference in radiographic evidence of periapical healing between one-visit and two-visit group at 12 months follow-up. Both groups exhibited a statistically significant decrease in PAI scores from baseline to 12 months evaluation. Both groups showed improved healing in almost similar percentage of teeth at the end of 12 months.