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Royal Dental College of Aarhus, Denmark

Documentation — Royal Dental College of Aarhus Study

Evaluation of subgingival treatment of periodontal pockets with Genius
Dental Research, Nice, France, 1998.

It has recently been suggested that short-duration pulsed Nd:YAG lasers may have a potential application in the treatment of moderate and deep periodontal pockets by vaporising subgingival organical debris. However, the results from several experimental and clinical studies contradict the benefits of subgingival laser therapy.

The study aimed to compare various clinical outcomes following subgingival Nd:YAG laser curettage or scaling and combined laser/scaling therapy in adult patients with moderate to severe periodontitis.

Materials and methods

Fifteen patients (eight males and seven females, ranging in age from 34 to 74 years old (a mean of 49 years old, with moderate to severe periodontitis) were selected for the study. Each patients presented minimum two sites in each quadrant without furcation involvements with a PPD of 6 mm. The study was carried out as a single blind, randomised clinical trial with a split mouth design, i. e., each patient received one of the three treatments (scaling, laser or laser/scaling) randomly assigned to one of the three quadrants of the mouth. The last quadrant served as untreated control.

One month prior to baseline, the patients received full mouth supra-gingival scaling, polishing of the teeth and oral hygiene instruction. At baseline, overall PPD was measured, and at the sites with PPD = 5 mm CAL and presence of PL a BOP was also recorded. These sites were then subjected to a treatment randomly assigned to each quadrant. Laser treatment was performed for 30 seconds per site using the Genius Nd:YAG laser (Mølsgaard Dental A/S, Copenhagen, Denmark) with a power – 5W, pulse frequency – 60 Hz, pulse duration – 250 microseconds, water – 7 and air – 3. Thus, each site received the energy of 150 J delivered through a 400-micron flexible optic fiber.

Scaling was performed with periodontal curettes until a smooth root surface was obtained. One month post baseline, experimental sites with positive BOP were re-treated as baseline.

To ensure consistency, all treatments were performed by one operator.

Periodontal registrations were performed “blindly” by another operator at 0, 1, 3 and 6 months. The Plaque Scores (PLS) or Bleeding Scores (BLS) were computed as proportions of the treated surfaces, presenting PL or BL per quadrant at each visit.


At baseline, all treatment groups presented similar (p>0.05) clinical parameters (Table 1). At one month, a significant (p<0.05, paired t-test) PPD-reduction was found after all therapies versus non treatment (Table 2). At three and six months, it was only significant after the combined laser/scaling therapy. Similar changes in PPD (p > 0.05) were found after scaling or laser treatment alone at all times.
Significant CAL-gain from baseline to one was observed following scaling or combined laser/scaling therapy (Table 2). Similar CAL-gains (p>0.05) were found after scaling or laser therapy alone at all times. At one month, a significant (p<0.05, the paired Wilcoxon single-ranks tests) reduction in the initial BLS was observed after laser or laser/scaling (Fig. 1), while at three an six months it was significant after all treatments and non-treatment. Reduction in the PLS was not significant during the follow-up (p>0.05)(Fig. 2).

1. Subgingival Nd:YAG laser therapy was similar to scaling improvements of clinical parameters of moderate and deep periodontal pockets.
2. Combined laser/scaling therapy was the most beneficial among the other therapies.
Table 1. Baseline characteristics of the clinical parameters (mean ± SD)

Treatment Group PPD mm PLS
5.8 ± 0.6 0.32 ± 0.1 0.69 ± 0.1
Laser 5.9 ± 0.6 0.34 ± 0.1 0.69 ± 0.1
Laser/scaling 5.8 ± 0.8 0.30 ± 0.1 0.67 ± 0.1
Control 5.7 ± 0.5 0.42 ± 0.1 0.69 ± 0.1


Table 2. Changes in PPD and CAL (mean ± SEM, mm) over time

0-1 0-3 0-6 0-1 0-3 0-6
0.6 ± 0.1a 0.7 ± 0.2 0.5 ± 0.2d 0.6 ± 0.2a 0.5 ± 0.2 0.3 ± 0.2
Laser 0.8 ± 0.1a 0.8 ± 0.1 0.6 ± 0.1d 0.7 ± 0.2a 0.5 ± 0.2 0.4 ± 0.3
Laser/scaling 1.0 ± 0.1b 1.0 ± 0.2c 1.0 ± 0.2a 0.9 ± 0.2c 0.6 ± 0.2b 0.9 ± 0.2
Control 0.4 ± 0.1 0.5 ± 0.1 0.4 ± 0.2 0.2 ± 0.2 0.3 ± 0.2 0.4 ± 0.2

a- statistically significant from the control )p<0.05), b- statistically significant from the control (p<0.01), c- statistically significant from the control (p<0.001), d- statistically significant from the laser/scaling (p<0.05).