Low-level laser therapy (LLLT) has been increasingly used over the past few decades in both medicine and dentistry. It has been suggested that LLLT may be helpful in pulpal wound healing following pulp exposure. The purpose of this study was to evaluate the histological changes in dental pulp tissue after a pulpotomy procedure using a low-level diode laser in comparison with the gold standard formocresol.

In this experimental split-mouth study, 20 teeth were randomly selected from five dogs. The animals were anesthetized and pulpotomized using a low-level diode laser (660 nm, 36 mW) and formocresol respectively. One week later, the pulpotomized teeth were extracted and subjected to histological evaluation. Histological changes seen in the pulp tissues of all the interventional groups were subjected to statistical analysis using Mann–Whitney U test for pairwise comparison; p < 0.05 was considered as statistically significant and p > 0.05 nonsignificant.

On histologic evaluation, least amount of inflammation and maximal healing was evident in the LLLT group. On the contrary, the formocresol group showed severe inflammation.

Low-level laser therapy promises to be a safe, minimally invasive, yet maximally effective modality for pulpotomy.

Prabhakar AR, Shagale AM, Yavagal C. Histological Evaluation of a Novel Pulpotomy Technique with Low-level Laser Therapy and Its Comparison with Formocresol: A Randomized Animal Trial. Int J Laser Dent 2016;6(1):1-5.

Recent innovations in bonding propose laser ablation as an alternative method to acid etching.

The objective of this study is to compare the effect of laser irradiation at medium-short pulse (MSP) mode, quantum-square pulse (QSP) mode, and acid etching on the shear bond strength (SBS) of orthodontic brackets to enamel.

Forty-two premolars were allocated to three groups (14 each): (1) 37% phosphoric acid etching; (2) erbium-doped yttrium aluminum garnet (Er:YAG) laser etching with MSP mode; (3) Er:YAG laser etching with quantum-square pulse mode. Metallic brackets were bonded with Transbond XT. After photo polymerization, the SBS values were recorded with universal testing machine. Surface morphology was evaluated with scanning electron microscopy (SEM). The remaining adhesive was assessed using adhesive remnant index (ARI).

Nonparametric test was used to analyze the statistical significance. A mean rank of 18.29 and 10.71 was obtained for QSP mode and acid etching with p = 0.015, 18.14; and 10.86 for MSP mode and acid etching with p = 0.019; and 14 and 15 for QSP mode and MSP mode with p = 0.748. Statistically significant difference was found between laser and acid-etched group. The SEM scan showed MSP mode with regular and uniform surface, like acid-etched sample, whereas QSP samples had irregular and severely rough surface. The ARI indicates that failure sites are mainly at the enamel/adhesive interface in the acid-etched and MSP mode group and at the bracket base/adhesive interface in QSP mode group.

Laser etching in MSP mode is a successful alternative to acid etching, and provides a safer debonding of the brackets from the enamel surface without causing fractures.

Sobha VV, Varma NKS, Ajith VV. Comparative Evaluation of Laser Etching and Acid Etching: An in vitro Study. Int J Laser Dent 2016;6(1):6-11.

The aim of the study was to determine and compare the pocket depths (PD), relative attachment levels (RAL), bleeding on probing (BOP) and plaque indices (PI) in patients treated with scaling and root planning (SRP) alone and along with diode laser.

The study was carried out on 30 subjects who fulfill the inclusion and exclusion criteria. Group I: 15 patients treated with SRP along with diode laser irradiation. Group II: 15 patients treated only with SRP. The clinical parameters were probing PD, RAL, BOP and PI which were recorded at base line, 7 days and after 1 month. Statistical analysis was done using Kolmogorov-Smirnov, Shapiro-Wilk, t-test, chi-square test.

The use of diode lasers as an adjunct to SRP during maintenance phase showed better results when compared to SRP alone. Moderate periodontal pockets with moderate attachment loss showed significant improvement in group I than in group II. There was no change in deep pockets with severe attachment loss in both groups.

The study shows that the specified laser parameter and the modality of application of the same results in faster healing. This can be recommended as an appropriate treatment for moderate pockets.

Suprit SS, Setty S, Thakur S. Diode Laser as an Adjunctive to Nonsurgical Periodontal Therapy during Maintenance Phase: A Randomized Controlled Clinical Trial. Int J Laser Dent 2016;6(1):12-17.

Erstwhile studies have emphasized the importance of establishing a secure fibrin linkage between the tooth-soft tissue interface for formation of a new connective attachment. Thus, periodontal regeneration is reliant on the constant adhesion, maturation and absorption of fibrin clots to the root surfaces which are compromised periodontally. Improved fibrin clot formation and blood cell attachment is being aimed by modification of the root surfaces with different agents. Limited studies have evaluated the attachment of blood cell component on various laser treated root surfaces individually.

Hence, the aim of this in vitro study was to evaluate and compare the adhesion of blood components on the root surfaces treated with citric acid, Nd:YAG, Er:YAG and CO₂ lasers by scanning electron microscopy (SEM).

The proposed study was conducted on 35 root specimens (5 × 5 × 1 mm) obtained from extracted periodontally compromised permanent teeth. The root specimens were randomly divided in five groups depending upon the type of treatment rendered. Group I: Untreated control group, group II: Citric acid (pH:1), group III: Nd:YAG laser (112.5 m J/pulse), group IV: CO₂ laser (12.5 J/cm²), group V: Er:YAG laser (120 m J). Following the respective treatments, fresh human whole peripheral blood obtained from a healthy donor was applied to the external surface of all root specimens. The specimens were then analysed and scored for the adhesion of the blood components with photomicrographs of SEM.

Statistically significant increase in the adhesion of blood components was seen in all the test groups compared to control group both citric acid and Er:YAG laser showed higher adhesion of blood cells to the root surface than the Nd:YAG laser and CO₂ laser.

Er:YAG laser enhanced the adhesion of blood components over the treated root surfaces. Hence, it can be safely used as a root bio-modifier ensuring stable fibrin linkage to promote periodontal regeneration.

Sabnis S, Gayathri GV, Chandra KK, Mehta DS. Comparison of Adhesion of Blood Components on Root Surfaces treated with Citric Acid, Nd:YAG, Er:YAG, and CO₂ Lasers: An in vitro Analysis. Int J Laser Dent 2016;6(1):18-23.

This ex vivo study compared the efficiency of Er:YAG laser to remove calcium hydroxide from root canal walls, especially from the apical third, with manual and ultrasonic irrigation technique by using a scanning electron microscopic (SEM).

Sixty-four single-rooted teeth were divided into 3 groups of 20 teeth each. The rest 4 teeth were used as control groups (2 positive and 2 negative control group). After coronal access, all teeth were instrumented by Protaper Next rotary files (Dentsply-Maillefer, Ballaigues, Switzerland) up to size F3, followed an irrigation protocol and filled with pure calcium hydroxide powder mixed with saline. Teeth were stored in an incubator for 7 days and then calcium hydroxide was removed using 3 techniques: Manually (group I), by ultrasonic irrigation (group II), by laser Er:YAG and x-pulse tip (group III). The teeth of control groups were instrumented as the experimental groups; no removal technique was applied in positive group, whereas in negative one, the root canals were left empty. Teeth were sectioned longitudinally and observed under SEM. Results were statistically analyzed with the Kruskal–Wallis test and Mann–Whitney test.

The results showed significant difference between laser and the other two groups in coronal and middle root third, but no statistic difference in apical third.

Laser improved the removal of calcium hydroxide in comparison with conventional techniques.

Kourti E, Pantelidou O, Kallis A. Removal Efficiency of Calcium Hydroxide Intracanal Medicament with Er:YAG Laser: A Scanning Electron Microscopic Study. Int J Laser Dent 2016;6(1):24-30.

Kallis A, Tolidis K, Gerasimou P, Gutknecht N, Koliniotou-Koumpia E. Comparative Study of the Restoration Quality in Cavities prepared with Er:YAG Laser in Quantum Square Pulse Mode and Conventional Method. Int J Laser Dent 2016;6(1):31-37.