Comparative Efficacy of Conventional Versus Diode Laser Assisted Root Canal Treatment in Reduction of Postoperative Pain and Healing of Periapical Lesion: A Randomized Controlled Clinical Trial

ABSTRACT

Background:

Laser assisted root canal treatment has emerged as a promising adjunct to conventional randomized controlled trials (RCTs).

Material and method:

To evaluate the same, we observed 90 patients (98 roots) with chronic periapical lesions; they were randomized into two groups (n = 45): diode laser and control. The level of pain was measured before and at 6, 12, 24, 48, and 72 hours after treatment using a visual analog scale. Cone beam computed tomography images were obtained before and 6 months after treatment to assess the healing of periapical lesions based on their apicocoronal, mesiodistal, and buccolingual diameters.

Result and conclusion:

It was observed that root canal disinfection by diode laser significantly decreased the postendodontic pain and resulted in a higher success rate in lesion resolution.

INTRODUCTION

The root canal treatment success has several criteria such as resolution of symptoms, periapical healing on radiographs, and histological evidence of healing. A number of factors affect the success of endodontic treatment, such as the severity of condition, the instrumentation technique, and the technology used for treatment.[1] In the recent years, use of laser in endodontics has gained increasing popularity, yielding acceptable results as an adjunct for disinfection of the root canal system and reduction of bacterial load.[2] Several studies have confirmed the optimal efficacy of laser therapy for reduction of postendodontic pain as well.[3] This study aimed to compare the effects of conventional and laser-assisted root canal treatment postoperative pain and healing of periapical lesions after 6 months.

MATERIAL AND METHOD

The study population is composed of 90 patients presenting to the Department of Endodontics, who required endodontic treatment of teeth with chronic apical periodontitis. The patients were between 18 and 60 years, and the diagnosis of chronic apical periodontitis was confirmed by radiographic examination and negative response to cold test and electric pulp test and no bleeding when exposing the pulp. Diabetic patients, immunocompromised patients, pregnant women, and those with a history of analgesic intake in the past 3 days or antibiotic intake in the past month were excluded. Teeth with periodontal disease or previous access cavity and those that could not be isolated by rubber dam were excluded as well.

The patients were allocated to the study groups with simple randomization. After recording the patients’ demographics, eligible patients were automatically randomized into the two study groups of conventional and diode laser by using a computer-generated system.

Conventional RCT group: The 45 cases in this group underwent root canal treatment using traditional techniques and instrumentation. The conventional randomized controlled trial (RCT) procedures followed standard protocols, including the use of manual or rotary files, irrigants, and obturation materials. The cases were treated by experienced endodontists who followed established guidelines.

Laser-assisted RCT group: After root canal preparation, it was rinsed with saline and cleaned with paper points. Next, a 940 nm diode laser (EPIC X, BIO - LASE) hand piece with 200 μm tip diameter was introduced into the canal to 1 mm from the apex and was then pulled back with a circular motion at a speed of 2 mm/s to - wards the orifice. After 20 s of laser irradiation in pulse mode, the dental substrate was allowed to rest for 10 s. Laser irradiation was repeated three times. The laser parameters included λ =940 nm and 2 W power. The root canals were filled with a mixture of calcium hydroxide and saline, delivered into the canal by a Lentulo spiral as medicament, and temporarily restored with Cavit between the treatment sessions.

Outcome Assessment: After completion of the first treatment session, the patients received a visual analog scale (VAS) form (graded from 0 to 10) to express their level of pain by selecting the score that best described their pain severity at 6, 12, 24, 48, and 72 h post treatment. The healing of periapical lesions was evaluated using cone-beam computed tomography (CBCT) scans at 3 months follow-up.

RESULTS

Of 90 patients, 71 (78%) were females and 19 (21%) were males. The mean age of patients was 34 years (range 18 to 60 years). A total of 90 teeth (98 roots) including anterior and posterior maxillary and mandibular teeth were evaluated.

Severity of pain: Figure 1 shows the severity of pain in the three groups. The mean pain score revealed statistically significant lower pain levels in the laser group compared with the conventional group at 6, 12, 24, and 48 hours (P = 0.02, P = 0.007, P = 0.001, and P = 0.004, respectively).

Figure 1.

Reduction in pain during time interval

			≤5 mm		>5 mm
			Conventional	Laser	Conventional	Laser
Mesiodistal lesion diameter (Lx)	Healing	Count	12	13	11	15
		%	100	76.47	100	88.24
	Healed	Count		4		2
		%		23.53		11.76
	P		0.271		0.277
Buccolingual lesion diameter (Lz)	Healing	Count	7	13	15	20
		%	100	86.67	100	90.91
	Healed	Count		2		2
		%		13.33		9.09
	P		0.52		0.278
Apicocoronal lesion diameter (Ly)	Healing	Count	12	10	13	15
		%	100	66.67	100	88.24
	Healed	Count		5		2
		%		33.33		11.76
	P		0.042		0.214

Radiographic Assessment: Sixty-seven patients (74 roots) showed up for the follow-up session (recall rate = 74%). It was observed in the laser group that the success rate was higher in the cases with lesions ≤5 mm in apicocor onal diameter (P = 0.042) and there was no positive correlation between the outcome of the therapy and the size of the periapical lesions diameters in all groups (P > 0.05).

DISCUSSION

The effect of laser on post-root canal treatment pain was in agreement with the previous studies. Diode laser exerts its anti-inflammatory effect by reduction of prostaglandin E2, bradykinin, histamine, acetyl choline, serotonin, and substance P and decreases the chronic pain through the A-delta and C fibers. Also, it decreases the speed of conduction and the action potential threshold of neurons and suppress neurogenic inflammation as such.[3]

Healing of a periapical lesion depends on a variety of factors, including but not limited to the quality of cleaning and shaping and the apical extent of obturation and preparation. The increased success rate of nonsurgical RCT with the use of lasers is mainly because of the efficacy of lasers in eradicating bacteria from the root canal. The penetration depth of lasers into dentinal tubules is more than that of conventional irrigation techniques. Bacteria could penetrate into dentinal tubules as deep as 1.1 mm, but 0.13 mm deep is the maximum penetration depth of chemicals used in RCT.[4] In addition to the bacteria residing in the root canal system, Bytyqi et al.[5] have demonstrated that laser irradiation can destroy the bacteria that live within a periapical lesion more effectively than conventional methods (P < 0.001). However, as the size of periapical lesions increases, the efficacy of lasers in killing bacteria decreases (P < 0.001), which could the reason for our present finding in >5 mm lesions.

CONCLUSION

The findings of this study contribute to the growing body of evidence supporting the use of lasers as an adjunct to existing conventional treatment approaches in root canal therapy, which will enhance the prognosis of endodontically treated teeth.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.