Indian Journal of Dental Research

: 2023  |  Volume : 34  |  Issue : 1  |  Page : 19--23

Evaluation of structural and compositional changes on the root surface exposed to diode laser (810 nm): An In-vitro study

Dorairaj Jayachandran1, Sunantha Selvaraj2, Shanmuga Priya3, Meena A Kukkamalla4, Vaishnavi Senkalvarayan2,  
1 Department of Periodontics, Vinayaka Mission's Sankarachariyar Dental College, Vinayaka Mission's Research Foundation-DU, Salem, Tamil Nadu, India
2 Department of Prosthodontics and Crown and Bridge, Vinayaka Mission's Sankarachariyar Dental College, Vinayaka Mission's Research Foundation-DU, Salem, Tamil Nadu, India
3 Department of Maxillofacial Surgery, Chettinad Dental College and Research Institute, Chennai, Tamil Nadu, India
4 Department of Periodontics, Manipal University College Malaysia, Melaka, Malaysia

Correspondence Address:
Dr. Sunantha Selvaraj
Departments of Prosthodontics and Crown and Bridge, Vinayaka Mission's Sankarachariyar Dental College, Vinayaka Mission's Research Foundation-DU, Salem, Tamil Nadu


Background: The laser therapy has been used as an adjuvant for conventional periodontal disease as they exhibit a bactericidal effect on scaling and root planning by its thermal and photo disruptive effects on the pathogens. This study focuses on the structural and compositional changes induced on the root surfaces of teeth following diode laser (DL) application with increasing quantum of exposure time. Objective: The objective of this study was to evaluate the structural and compositional changes on the root surface of extracted human permanent teeth after application of DLs (810 nm) with varying time interval. Materials and Methods: Twenty samples of single-rooted periodontally compromised extracted teeth were utilized for this study. Root planning was done and the roughness caused by the instrumentation was measured using profilometric analysis. Then, the samples were divided into four groups, with DL application time: Group 1 – laser application for 15 s, Group 2 – laser application for 30 s, Group 3 – laser application for 45 s, and Group 4 – laser application for 60 s. A scanning electron microscope was used to examine the cemental surface and energy-dispersive X-ray analysis software assesses the compositional changes of the teeth in each group. Results: This study reveals that on exposure of DL (810 nm) on the root surface when time of exposure increases, there were relative increases in surface irregularities and charring. There were significant changes in the chemical composition of the tooth surface.

How to cite this article:
Jayachandran D, Selvaraj S, Priya S, Kukkamalla MA, Senkalvarayan V. Evaluation of structural and compositional changes on the root surface exposed to diode laser (810 nm): An In-vitro study.Indian J Dent Res 2023;34:19-23

How to cite this URL:
Jayachandran D, Selvaraj S, Priya S, Kukkamalla MA, Senkalvarayan V. Evaluation of structural and compositional changes on the root surface exposed to diode laser (810 nm): An In-vitro study. Indian J Dent Res [serial online] 2023 [cited 2023 Sep 26 ];34:19-23
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Chronic periodontitis is an infectious disease affecting the periodontium caused by periodontal pathogens resulting in inflammation, loss of attachment, bone destruction, and gingival retraction. The utilization of laser therapy widely serves as an effective alternative or as an adjunctive therapy to conventional periodontal treatment modalities. Literature shows that numerous studies have been carried out to support the concept of laser therapy in periodontal disease management. Different types of laser are being used for various clinical dental procedures.[1] A DL is a semiconductor laser with a wavelength between 800 nm and 980 nm. The wavelength of laser and the target tissue's optical characteristic influences the degree of absorption of laser by the tissues. The DL usually composed of a combination of gallium (Ga), arsenic (Ar), aluminium (Al), indium (In), and other elements. DLs are suitable for soft-tissue operations and preferred for surgical procedures for soft tissue that involves gingiva and oral mucosa carrying out procedures like curettage and sulcular debridement.[2]

 Rationale for Laser Treatment

The conventional nonsurgical periodontitis treatment is done by mechanical debridement of the tooth surface from debris, inflammation, and toxins using hand instrumentation and SRP (scaling and root planning).[3] DLs effectively used to debride the pathogens and their toxins. The DL not only exhibits bactericidal and detoxification effects, they can also enable hemostasis with accelerated angiogenesis and accelerated wound healing by enhancing the collagen synthesis.[4] DL is the most effective mechanism of removal of epithelial lining with a thermal ablation. Another advantage of DLs is its small size and low cost.[5] Using DLs, de-epithelialization of the tissues can be done which requires less anaesthesia and patient has less postoperative discomfort or pain when compared to mechanical debridement.[3]

 Materials and Method

The present study was approved by the institutional ethics committee with reference no: VMSDC/IEC/approval no 273. This study was carried out in four stages: (1) sample collection and preparation, (2) visualization under profilometer, (3) DL treatment, and (4) SEM and energy-dispersive X-ray analysis (EDAX).

Collection of experimental sample

Twenty mandibular and maxillary single-rooted periodontally compromised teeth indicated for extraction were selected for this study. The selected teeth were extracted and immediately cleansed with running water for approximately 20 s to remove the blood and surface debris.

The sample tooth has to be periodontally compromised tooth (single-rooted tooth): intact root surface, absence of caries, presence of gross hard and soft-tissue debris, and flat root surface preferable. Teeth with more root concavities or convexities which impeded proper planning of root surfaces were excluded.


Root planning

Root planning procedure was done at the middle third of the proximal root surfaces. Gracey curettes no. 1, 2, 3, and 4 were used for the procedure. It was carried out on each sample in apicocoronal direction using 10 strokes at 45° angulation and with constant lateral pressure. The procedure was done by the single operator to avoid any errors. After root-planning procedure, the roughness was evaluated using stylus profilometer.

Evaluation of postinstrumentation roughness

The surface roughness after instrumentation was assessed using contact mode stylus profilometer. For each sample, 10 readings were made and the mean was calculated. Ra and Rz were the surface roughness parameters used in this study. “Ra is defined as the arithmetic mean of the absolute values of vertical deviation from the mean line through the profile.” The area between the profile and the mean line above the line equal to that below the mean line gives the mean line.[6] “The Ra was calculated over the entire measured array and Rz is defined as ten points, i.e., the average absolute value of the five highest peak and the five lowest valleys over the evaluation length.”[6]

Sample preparation

Based on the profilometric value, the teeth samples were selected. All the samples were cleansed and stored in saline solution for a week for hydration. After this procedure, the teeth were autoclaved in wet medium and their crowns were sectioned with a diamond disk. The tooth sample sizes were standardized to dimension of 5 × 5 × 1 mm.

Diode laser application

After the preparation of the samples, they were divided into four groups: Group 1 – laser application for 15 s, Group 2 – laser application for 30 s, Group 3 – laser application for 45 s, and Group 4 – laser application for 60 s. DL with 810 nm wavelength was used for this study (AMD-PICOSO LITE 810 nm). The setting was standardized for all the groups as 1 W, continuous mode, and non-contact mode by placing the tip approximately 1 mm away from the specimen.

The surface roughness of the specimens for each instrumented tooth: 10 readings were made by profilometer through contact mode and arithmetic means were determined [Table 1]. Mean score of Ra is 0.003 and mean score of Rz is 0.02 with the standard deviation of 0.0012. Since the P value is greater than 0.05, it is found that no significant difference is found in mean score. Ra and Rz were the surface roughness metrics employed in this investigation.{Table 1}


Profilometeric analysis

The surface roughness of the specimens was quantified after instrumentation using contact-based stylus profilometer. For each instrumented tooth, 10 readings were made.

SEM AND EDAX analysis

A SEM analysis and EDAX were done and single investigator and double-blinding trial were done to avoid any bias.

Statistical analysis

Scanning electron microscopic analysis

SEM analysis was done to analyse the micromorphological changes in cementum surface area. Group 1 showed the sign of debris and minimal surface irregularities [Figure 1]. Group 2 showed the sign of debris and few surface irregularities of the form of cracks which when compared to group 1 was found to be significant [Figure 2]. Group 3 shows debris and increased surface irregularities with extensive cracks when compared to groups 1 and 2 [Figure 3]. Group 4 shows debris with focal areas of surface irregularities in the form of extensive cracks and peelings and charring of the root surface [Figure 4].{Figure 1}{Figure 2}{Figure 3}{Figure 4}

EDAX analysis

EDAX was a technique used to identify the elemental material composition of the root surface of teeth in each group. The average value of the surface composition in cementum was taken.

Compositional changes

EDAX reveals that a significant composition changes in the cementum as the exposure time of laser application increased. When the intensity of laser application increased, there was noticeable change, thereby corresponding increase in the amount of carbon and reduction in calcium and phosphorus [Graph 1]. The contributing factor could be due to the charring and peeling of the cementum surface which occurred during the laser application.[INLINE:1]


The periodontal therapy aims to restore infected root surfaces, thereby enhancing its biocompatibility and improving the attachment of periodontium on the treated root surface. The efficacy of the conventional mechanical debridement is based on the operators' skill and experience. So the complete access into periodontal pocket and disinfection by debridement may vary with the operator and the clinical scenario. In order to overcome these shortcomings, an adjuvant therapy of systemic and local drug delivery was recommended along with conventional mechanical debridement to reduce the bacterial load. Such kind of drug therapy may not be effective against the resistant microorganisms.[2]

In order to overcome the shortcomings of mechanical debridement, introduction of laser is used as an adjunctive tool along with mechanical debridement.[2] Soft-tissue laser radiation acts as effective treatment modality for the periodontal treatment due to its bactericidal effect and detoxification effect removal of epithelial lining and granulation tissue and enhances healing potential which is essential for the success of periodontal therapy.[5]

After root-planning procedure, it leaves smear layer on the root surface which hampers the attachment of fibres onto the root surface. Use of laser irradiation in non-contact mode after root planning removes the smear layer on the root surface. Pocket lining and granulation tissues can be removed using the laser tip inside the periodontal pocket and contact mode in zig-zag motion apico-coronally along with root surface debridement. High probability of biostimulating effects by the scattering and penetrating laser energy on the cells surrounding the target tissue during irradiation is observed. So the soft-tissue laser might be helpful for the reduction of inflammation and healing of periodontal tissues.[2] Therefore, laser irradiation in periodontal pockets could have some clinical outcomes in improving clinical parameters so could be used as an adjunct to non-surgical periodontal therapy. There are possibility root surfaces exposed to laser radiation that might experience some surface irregularities which could be removed and made smooth by the second SRP after laser radiation.

This study was conducted to evaluate the structural and the micromorphological effects on root surfaces treated with DLs (810 nm) at different exposure time intervals and therefore check the chemical composition of the treated root surface. This study revealed relative increase of damage of root surface with surface irregularities in the form of cracks and charring with increasing exposure time of application of DL.

These findings correlate and concur with the studies done by Schwarz et al. in 2001[7] and Morlock et al. in 1992[8] which said that when laser energy is applied directly to the root surface, there was severe damage, which included cracks and grooves.

According to Kreisler in 2002, the DL application causes damage to the periodontal hard tissues, when radiation parameters are not proper.[9] Furthermore, the studies done by Trylovich et al. (2000),[10] Spencer et al. (1992),[11] Thomas et al. (2000),[12] Tewfik et al. (1994),[13] and Ito et al. (1993)[14] led the American Academy of Periodontology to conclude that neither DLs nor Nd: YAG is an alternative to root planning. It can be an adjunct rather than replacement.

The discrepancy observed between the results of this study and those of previous studies may be due to the differences in wavelength, power, frequency, and duration of laser irradiation, as well as to the variations in this study design.

The current study was limited to an in-vitro study. This pilot study can further be investigated as randomized clinical trials with more patients as in-vivo study, with longer follow-ups which will possibly benefit by adding laser therapy to conventional non-surgical periodontal treatment.


Many studies have proven that DLs can effectively remove microorganisms from the soft-tissue wall of the periodontal pockets. Employing proper parameters and methods is a significant factor in the use of lasers to prevent accidental or excessive exposure which may cause irreversible and potential damage. In the present study, we found that as the exposure time of application of the DL on the root surface was increased, there was a corresponding increase in the surface irregularities on the root surface in the form of cracks and charring. When using the laser on the root surface, exposure time should be kept minimum to avoid adverse effects.

Thus to conclude, DLs are safe and effective in nonsurgical periodontal treatment when used as an adjuvant to remove the pathogens from the soft-tissue wall without directing to the root surface.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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