Comparison of Effectiveness of Diode Laser as an Adjunct to Scaling and Root Planing and Scaling, Root Planing Alone in Treatment of Chronic Periodontitis—A Randomized Split-mouth Clinical Study

INTRODUCTION

Chronic periodontitis (CP) is an inflammatory periodontal disease that is most prevalent, affecting the world’s population which accounts for 10%. A pathogenic consortium of bacteria surrounding the teeth starts up the process of disease initiation, as a result of this, the immune-inflammatory response leads to the occurrence and progression of the disease from gingivitis to periodontitis in susceptible people. Periodontitis is a chronic inflammatory disease of periodontium, which is of multifactorial origin that is caused due to the accumulation of plaque biofilm and calculus on the root surface of the tooth, which leads to continuous destruction of the periodontal ligament and alveolar bone, along with the formation of pocket, recession, or both.¹

Production of inflammatory cytokines in excess, especially interleukins (ILs) and tumor necrosis factor-α (TNF-α) are directly related to destroying periodontal tissues. Gingivitis progresses into periodontitis if left untreated. Hence, mechanical plaque control is a mode of therapeutic approach in halting the progression of gingivitis to periodontitis.²

Plaque removal performed using manual and powered instruments has shown effective removal of plaque biofilm and calculus from the root surfaces, thereby the bacterial load in periodontal pockets will be reduced.³

Complete removal of subgingival plaque biofilm and calculus is not possible while carrying out the instrumentation in deeper periodontal pockets and furcations, because it is doubtful whether they can reach the surfaces of roots of the teeth.

For these various reasons, different local or systemic antibiotics are used to treat periodontitis. Furthermore, it will be very difficult to maintain these antibiotics at a concentration which gives therapeutic benefits in terms of reduction of the periodontal pocket, and also there is an enormous concern regarding the development of antibiotic resistance.⁶

Because of this aspect, and also the use of laser radiation within the periodontal pocket causes sulcus disinfection (antibacterial), photostimulatory effect, the laser has gained much interest and its been promising therapeutic modality in the specialty of periodontology. As conventional mechanical instrumentation cannot reach certain sites, the intended therapeutic benefit cannot be achieved but the same can be achieved by lasers, as they cause good tissue ablation, bactericidal and detoxification effects.⁴ The laser wavelengths most commonly used in the field of periodontology include erbium:yttrium–aluminum–garnet (Er:YAG) lasers, diode lasers (DLs), neodymium:yttrium–aluminum–garnet (Nd:YAG), and the carbon dioxide (CO₂) laser.⁴

In 1995, FDA approved the use of a DL [gallium–aluminum–arsenide (Ga–Al–As; 810 nm)] for oral soft tissue surgery and in 1998 for sulcular debridement. A DL is a semiconductor laser that converts electrical energy into light energy, they have high electrical to optical efficiency, are small lightweight, and compact, hence portable as compared to other solid-state and gas lasers.⁴

Application of DL with a wavelength between 655 and 980 nm is known to accelerate wound healing bringing about angiogenesis, through the facilitation of formation of collagen, and augmentation of growth factor.⁵ Hence, these cumulative effects of DL promote healing of periodontal tissues, which necessitates the same of the same to obtain the intended therapeutic benefits.

With consideration of the above advantages of DL in causing sulcus disinfection and photostimulatory effects, its use as an adjunct to the scaling and root planing (SRP) can be the choice of treatment in treating CP patients.

Therefore, the purpose of this study is to compare the clinical effects of DL as an adjunct to SRP and SRP alone in the treatment of CP patients.

MATERIALS AND METHODS

This study was a randomized, single-blinded, controlled, parallel-group clinical study. It was conducted at Yenepoya Dental College and Hospital, Department of Periodontics, Mangaluru from November 2018 to August 2019. The clinical trial approval was given by the Institutional Ethics Committee (2017/292 dated 27/11/2017). Informed consent was obtained from each of the subjects voluntarily, after providing them with a detailed information brochure regarding the study. After receiving the informed consent, we adhered to the principles of the Helsinki declaration that are outlined when human subjects are involved.

RESULTS

DISCUSSION

Scaling and root planing is the primary recommended approach to control periodontal infection. However, the complete removal of bacterial biofilm and their endotoxins in deeper, inaccessible areas of the pockets and furcation sites is often difficult to achieve by performing SRP alone. So, this necessitated the use of additional therapeutic strategies as an adjunct to SRP.

The use of the laser as an adjunct to conventional SRP is based on the understanding that the lasers can cause good tissue ablation, with strong bactericidal and detoxification effects, and also can reach deeper sites which are inaccessible to the conventional mechanical instrumentation. Application of DL with a wavelength between 655 and 980 nm is known to accelerate wound healing through the facilitation of formation of collagen, brings about angiogenesis and augmentation of growth factor.⁵ However, despite the potential benefits of the use of lasers in periodontology, there are limited clinical evidences that have confirmed the use of lasers as an adjunct to conventional periodontal therapy may provide additional benefits in the treatment of subjects with CP.

The present study aimed to compare the effectiveness of DL as an adjunct to SRP and SRP alone in the treatment of subjects with CP. The results indicate that SRP using hand instruments and an ultrasonic device alone (group I) or in combination with a DL (group II) provide significant improvements in clinical parameters like plaque index, GI, BI, PPD, and CAL in both groups I and II from baseline to 3 months, i.e., after the treatment of subjects with CP.

In the present study, there are no statistically significant improvement in plaque, gingival and bleeding indices from baseline to 3 months, with adjunctive use of 810 nm DL with SRP, this particular finding is in agreement with Assaf et al.⁷ who used the same specifications of DL irradiation which was used in our study. Although both groups I and II showed positive results after the treatment with very high statistical significance, group II demonstrated better improvements in terms of mean difference of PPD reduction on mesial and distal aspects in moderate pockets measuring 4–6 mm during baseline to 3 months. The mean difference in the gain in the CAL has shown very high statistically significant values on the distal side of the laser-treated teeth, however, the improvement was not statistically significant on the mesial side. This observation is in line with Dukić et al.⁸ study, where they found no improvement in the CAL at all. Thus, the possible explanation for the reduction in PPD could be the gingival tissue retraction rather than clinical attachment gain. But, there is a statistically significant improvement in CAL on the buccal aspect, this can be attributed to the de-epithelization of periodontal pockets leading to increased connective tissue attachment which is in agreement with the study conducted by Kreisler et al.⁹ and Kamma et al.¹⁰

Caruso et al.¹¹ demonstrated that laser as an adjunct to SRP has a bactericidal effect, which was assessed by the collection of plaque samples using PCR. Thus, the elimination of bacteria from periodontal pockets promotes a considerable amount of healing of periodontal tissues.

De Micheli et al.¹² conducted a similar study using a high power DL in combination with SRP performed on day 1 and 7. They did not get significant improvements in clinical parameters in contrast to our findings. The better results in our study could be due to the extended use of laser for 3 times (day 1, 7, and 21). Similarly, Ribeiro et al.¹³ did not observe differences in the measured clinical parameters between test and control sites, here results may differ because of the difference in the interval of laser irradiation which was done after 1, 2, and 3 days of SRP. Similarly, De Micheli et al.¹² observed no difference in terms of PPD and CAL in sites irradiated with a laser at the end of the 6th month follow-up period.

In the present study, split-mouth design was followed, both groups I and II received SRP, and only group II received laser irradiation of 810 nm, continuous wave mode, the output power of 2.5 W, input (vol)-16.8 V, for 20 seconds in apico-coronal direction with optic fiber diameter being 400 μm on days 7, 14, and 21 after SRP, whereas group I received no other treatment except SRP.

The above-mentioned specifications of laser irradiation were chosen based on the observations made in a systematic review conducted by Qadri et al.⁵ which suggests that the use of these laser power settings are sufficient to eliminate the periodontal pocket epithelium. The greater reduction of PPD in the current study could be attributable to the use of laser irradiation with these specifications.

The application of DLs on periodontal tissues has demonstrated the increase in the mRNA expression of insulin growth factor-beta and vascular endothelial growth factor in human gingival fibroblasts which demonstrates a potent effect on the metabolism of connective tissues and it also brings down the production of matrix metalloproteinase-8 which plays an important role in the degradation of collagen fibers.⁵

The hemoglobin in the soft tissue of periodontal pockets acts as an absorber chromophore and as an endogenous dye for a high power DL, thereby enhancing the effect of the laser at the site of the application, which demonstrates the bactericidal effect of a DL.¹²

In the present study, the improvements in terms of clinical parameters have been demonstrated in groups I and II individually, this result is in agreement with a study conducted by Dukić et al.⁸ The possible explanation for this result is that SRP is known to stop the inflammatory processes by reducing the number of pathogenic periodontal microorganisms, which will also facilitate the removal of smear layer, bacterial endotoxins, and contaminated root cementum, which in turn facilitates healing of periodontal tissues in shallow to moderate periodontal pockets but not in deeper pockets which necessitates further adjunctive use of various other treatment modalities.

To the best of our knowledge, this is the first study to observe the differences in PPD and CAL in site-specific manner rather than considering the total average value of PPD and CAL around each tooth. Following this pattern of assessment of PPD and CAL has rendered us more accuracy in comparing the potential benefits of each treatment modality that has been provided in this study.

Other important observations that were made in this study are:

• Maintenance of good oral hygiene potentiated the treatment modalities that have been provided in the course of the study.
• The compliance of the patients becomes an important and integral part of any treatment plan and outcome. In this regard, better compliance of patients can be obtained if the treatment protocol is explained in their language.

However, there was no statistically significant difference between groups I and II in terms of PPD and CAL in buccal, palatal/lingual aspects, and mesial aspects, palatal/lingual aspects, respectively. De Micheli et al.¹² suggested the use of power meter while working with lasers to assess and visualize the parametric values which quantify the actual amount of energy that is present at the tip of the fiber optic delivery system and how much energy is lost when the laser beam is transmitted through fiber optic. Dukić et al.⁸ opined that the literature does not show any standard procedures regarding energy, group distribution, modes of irradiation, and time taken for a bacterial reduction in the periodontal pocket, which hinders the precise analysis of the results.

The study will have a broader scope if we include the microbial assessment; periodontal pocket with varying depths and extend the study for a longer period of time.

The results of the study demonstrated that, compared with SRP alone, adjunctive use of 810 nm DL with SRP offers a good additional benefit in the treatment of subjects with CP. According to a precise site-specific analysis of results, the adjunctive use of 810 nm DL to conventional SRP showed moderate improvement in terms of PPD and CAL. Furthermore, additional longitudinal, randomized, microbial, and controlled clinical trials with larger sample size and laser irradiation for periodontal pocket measuring %3E;6 mm are necessary to adequately test the potential benefits of DL-mediated periodontal therapy and it is also necessary to provide standard criteria for periodontal laser therapy in terms of laser power settings and mode of irradiation which would facilitate the analysis of the obtained results.

CONCLUSION

Within the limits of the present study, it can be concluded that the adjunctive use of 810 nm DL with SRP provides moderate additional clinical benefit in moderate periodontal pockets 4–6 mm.

CLINICAL SIGNIFICANCE

This study signifies that using noninvasive laser therapy, potential clinical benefits can be obtained in terms of reduction of periodontal parameters.

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