|Year : 2014 | Volume
| Issue : 1 | Page : 2-7
Effect of diode laser on periodontally involved root surfaces: An in vitro environmental scanning electron microscope study
Lohar Nilam Baburao, Byakod Girish Neelkanth, Hegde Rashmi Vivek, Muglikar Sangeeta Dilip
Department of Periodontology, M. A. Rangoonwala College of Dental Sciences and Research Center, Pune, Maharashtra, India
|Date of Web Publication||9-Jun-2014|
Lohar Nilam Baburao
7, Gold Leaf, Bhakti Marg, Off Law College Road, Erandwana, Pune - 411 004, Maharashtra
Source of Support: None, Conflict of Interest: None
Context: Diode laser has been used as adjunct to scaling and root planing in the treatment of periodontitis. However, inadvertent effect of diode laser on root surface needs more evaluation. Aims: The aim of this study was to evaluate and compare the structural and compositional changes in extracted human permanent teeth following scaling, root planing, and diode laser (980 nm) application in noncontact mode. Settings and Design: This was an in vitro environmental scanning electron microscope (ESEM) study. Materials and Methods: Thirty single rooted periodontally involved teeth indicated for extraction were selected and divided into two groups. In Group 1, 15 teeth were treated with scaling and root planing followed by diode laser application in noncontact mode (2 W, 30 s) and in Group 2, 15 teeth were treated with scaling and root planing alone. An ESEM was used to examine the cemental surface. Compositional changes were assessed using EDAX software. Statistical Analysis Used: The statistical comparison of compositional changes and root surface alterations in two groups was carried out using independent sample t-test and Chi-square test, respectively. P < 0.05 was considered as statistically significant. Results: About 53.3% of teeth in Group 1 showed mild surface changes (Score 4) as compared to only 13.3% of teeth in Group 2. The results were statistically significant ( P - 0.001). This study also reveals a significant amount of compositional changes in Group 1 as compared with Group 2. Mass % of carbon and oxygen is significantly increased in Group 1 as compared with Group 2. Conclusions: In this study, mild root surface alterations were seen in the form of cracks and charring after diode laser application in noncontact mode.
Keywords: Compositional changes, diode laser, root surface alterations
|How to cite this article:|
Baburao LN, Neelkanth BG, Vivek HR, Dilip MS. Effect of diode laser on periodontally involved root surfaces: An in vitro environmental scanning electron microscope study. J Dent Lasers 2014;8:2-7
|How to cite this URL:|
Baburao LN, Neelkanth BG, Vivek HR, Dilip MS. Effect of diode laser on periodontally involved root surfaces: An in vitro environmental scanning electron microscope study. J Dent Lasers [serial online] 2014 [cited 2020 May 29];8:2-7. Available from: http://www.jdentlasers.org/text.asp?2014/8/1/2/134108
| Introduction|| |
Periodontal disease is initiated by pathogenic plaque biofilm and characterized by bacteria induced inflammatory destruction of tooth-supporting structures and alveolar bone. , Periodontal pathogens evade the host response by releasing virulence factors in surrounding environment ,,, and cannot be completely eradicated with nonsurgical periodontal therapy due to their tissue invasive property (e.g., - Porphyromonas gingivalis). 
The adjunctive use of lasers in the treatment of inflammatory periodontal diseases is gaining popularity in the dental practice.  Thermal and photo-disruptive effects of the laser cause the complete elimination of periodontal pathogens. ,,,, Owing to deeper depth of penetration of Lasers in areas, which are not accessible to conventional instrumentation, we can achieve excellent bactericidal and detoxification effects. 
Several different wavelengths of lasers can be used in periodontics. The high-power lasers commonly used in periodontics are CO 2 ( 10,600 nm), neodymium-doped: Yttrium aluminum garnet (Nd: YAG) (1064 nm), erbium: YAG (Er: YAG) (2600-2900 nm), erbium, chromium: Yttrium, scandium, gallium, garnet (2780 nm) and, more recently, diode lasers (810, 980 nm).  The wavelength of diode lasers is defined by the composition of the base compound. The most widely used lasers in this family are the gallium-aluminum-arsenide laser (810 nm) and the indium-gallium-arsenide laser (980 nm). Diode lasers operate in continuous and/or pulsed modes and are very effective for soft tissue applications, offering excellent incision, hemostasis, and coagulation.  With these wavelengths, the penetration into biological tissues is relatively high and the penetration depth is estimated to be approximately 0.5-3 mm. 
The diode laser is absorbed selectively by pigmented chromophores, including melanin and hemoglobin and possibly the pigments contained in periodontopathic bacteria, which could make it ideal for destruction of such bacteria. , The diode laser thus has a bactericidal effect and helps to reduce inflammation in the periodontal pockets in addition to scaling.  However, one of the possible drawbacks of diode laser application, especially in the subgingival scenario, is the accidental contact of laser energy to the root surface, which could lead to severe and irreparable damage to the root surface morphology and the pulp. Hence, a study was planned to examine the structural and compositional changes of extracted human permanent teeth after diode laser (980 nm) application in noncontact mode and to evaluate and compare the root surface and compositional changes following scaling, root planing and diode laser (980 nm) application in noncontact mode.
| Materials and Methods|| |
The study was carried out in Department of Periodontology in M. A. Rangoonwala College of Dental Sciences and Research Center, Pune. The study design and methodology was approved by the Ethical Committee of the institution and all the procedures were performed after obtaining the informed consent from the patient.
Thirty single rooted teeth with no visible calculus and no history of scaling and root planing were selected for this study. All teeth were associated with severe bone loss and hopeless prognosis and thus were indicated for extraction. Immediately after extraction, the teeth were immersed in phosphate buffered saline solution in glass. They were then stored in these containers at 4°C.
Samples were divided into two groups as follows (n = 15):
- Group 1: Fifteen teeth were treated with scaling and root planing followed by diode laser application in noncontact mode
- Group 2: Fifteen teeth treated with scaling and root planing alone.
Scaling was carried out with the help of Satelec® [Acteon] ultrasonic scaler followed by root planing with area specific curette.
After scaling and root planing samples in Group 1 were treated with Diode Laser application (980 nm) in noncontact mode (approximately 1 mm away from root surface) in linear motion at the power setting of 2 W for the time period of 30 s. Laser beam was maintained parallel to root surface.
An environmental scanning electron microscope (ESEM) was used to examine the cemental surface and compositional changes of the roots of teeth in each group were assessed using EDAX software. The ESEM analysis was performed by an independent examiner to avoid bias.
Root surface changes were evaluated using scoring criteria given by Schwarz et al. in 2001 [Table 1]. 
|Table 1: Scoring criteria for root surface alterations given by Schwarz (2001)|
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The statistical comparison of compositional changes in two groups was carried out using independent sample t-test after confirming the underlying normality assumption. While the statistical significance of the distribution of root surface alteration scores across two study groups was tested using Chi-square test. P < 0.05 was considered to be statistically significant throughout the study. The entire statistical analysis was performed using Statistical Package for Social Sciences (SPSS version 12.0) for MS Windows.
| Results|| |
Root surface changes
Root surface changes were evaluated using scoring criteria given by Schwartz et al., (2001). 53.3% of teeth in Group 1 showed Mild surface changes (Score 4) whereas 46.7% of teeth showed slight surface changes (Score 3) [Figure 1] and [Figure 2]. In Group 2 60% of teeth showed Slight (Score 2) and 26.7% of teeth showed Slight (Score 3) surface changes [Figure 3] and [Figure 4]. Only 13.3% (2) of teeth showed Mild (Score 4) surface changes (Graph 1) [Additional file 1]. The results were statistically significant (P - 0.001) suggesting that application of diode laser caused more surface alterations as compared with scaling and root planing alone [Table 2].
|Figure 1: Environmental scanning electron micrograph of the root surface in Group 1 (×50)|
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|Figure 2: Environmental scanning electron micrograph of the root surface in Group 1 (×500)|
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|Figure 3: Environmental scanning electron micrograph of the root surface in Group 2 (×50)|
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|Figue 4: Environmental scanning electron micrograph of the root surface in Group 2 (×500)|
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This study reveals a significant amount of compositional changes in Group 1 as compared with Group 2. Mass % of carbon and oxygen is significantly increased in Group 1 as compared with Group 2 (P - 0.001 statistically significant). The reason could be attributed to the charring and peeling, which occurred during the laser application [Table 3].
| Discussion|| |
Diode laser therapy in combination with scaling supports the healing of the periodontal pockets by eliminating bacteria. In addition, the diode laser in combination with scaling produces moderate clinical improvement over conventional treatment. Although the Food and Drug Administration approved oral soft-tissue surgery in 1995 and sulcular debridement in 1998 by means of a diode laser,  effect of the high-power diode laser irradiation of periodontally involved root surfaces needs more investigation.
The diode laser has characteristics similar to those of the Nd: YAG laser. Since both lasers offer high penetrability into biological tissues, it may be suggested that the tissue effect is due to the energy that penetrates into the tissues; however, this is not always the case. Part of the light that these lasers emit is converted into heat by refraction or diffused reflection at the tip end, creating a condition called hot tip. When the tip touches soft tissue, carbonized debris adheres to the tip's end, increasing the temperature to more than 500°C. The tissue is coagulated and vaporized due to contact of the overheated tip rather than from the laser light itself. The hot tip effect is not a true and direct laser effect; rather, it is a secondary effect.
Much of the energy of the diode laser is consumed at the contact tip, which means that less laser light reaches the targeted tissue. As a result, diode laser's effect on soft tissue depends more on the hot tip effect. ,
This study was carried out to evaluate and compare the root surface and compositional changes following scaling, root planing and diode laser (980 nm) application in noncontact mode. In this study, root surfaces treated with scaling and root planing followed by diode laser application showed slight to mild superficial alterations as compared to scaling and root planing alone.
Numerous studies have shown improvement in periodontal parameters after use of diode laser as an adjunct to scaling and root planing. Moritz et al. (1998)  showed that diode laser has bactericidal effect and helps to reduce inflammation in periodontal pockets in addition to scaling and root planing. Other authors (Dörtbudak et al. 2001,  Bach et al. 2000  ) have proved good results with the use of diode laser to decontaminate during periodontitis and periimplantitis surgical treatments.
Borrajo et al. (2004)  used 980 nm diode laser at 2 W power as an adjunct and showed moderate clinical improvement over traditional treatment. Similar findings were reported by Dukiζ et al. (2013)  who used 980 nm diode lasers at peak power of 2 W. However, Yilmaz et al. (2002)  have not found additional benefit in the use of gallium arsenide laser with regard to other types of periodontal treatment.
Diode lasers at high energy levels, especially in a continuous mode, can cause root surface alterations in the presence of blood and elevated temperatures, depending on the power employed. Schwarz et al. (2003)  showed that when lasers are applied to root surface there is severe damage to root surface. However, Kreisler et al. (2002)  have reported no detectable alterations on dry or saline moistened root surfaces irradiated with diode laser at 1.5 W; detectable alterations were only noticed when a thin blood film covered the root surfaces. This discrepancy could be due to the analysis techniques used. Kreisler et al. (2002)  used reflected light microscopy to look for blackening due to carbonization of the root surface, whereas in the present study, these surfaces were analyzed by ESEM.
Angulation of laser beam also plays an important role. Kreisler et al., (2002)  observed that the root surface damage is greater when angles close to 90° were used. In this study, slight to mild root surface alterations were present even when the angle of irradiation was close to 0° (parallel to the root surface). In contrast, Haypek et al. (2006)  observed minimum root surface alterations when diode laser beam was parallel to the root surface.
Significant amount of compositional changes in the cementum are denoted by increased amount of carbon and corresponding reduction in calcium and phosphorus. Similar results were shown by Pai et al. (2005).  Authors suggested that compositional changes can be attributed to charring which is caused by the heat generated by laser.
| Conclusions|| |
In this study, we found that diode laser can cause mild root surface alterations in the form of cracks and charring. It can thus be concluded that diode lasers are safe and effective instruments in nonsurgical periodontal treatment as long as the laser energy is not directed onto the root surface. Proper parameters and methods should be employed to prevent accidental or excessive exposure, which may cause irreversible and potential damage.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3]