The specimens were divided into 8 different groups : 1) untreated control 2) scaling and root planing only 3) laser treated using 150mJ/pulse, 1sec, 5sec, contact mode 4) laser treated using 200mJ/pulse, 5sec, contact mode 5) laser treated using 150mJ/pulse, 1sec, non-contact mode 6) laser treated using 200mJ/pulse, 5sec, non-contact mode 7) laser treated using 150mJ/pulse, 1sec, contact mode with water irrigation 8) laser treated using 200mJ/pulse, 5sec, contact mode with water irrigation.

All specimens were prepared for evaluation by scanning electron microscopy(SEM). Specimens from Group 2 exhibited a smear layer of scale like texture with parallel instrument tracks resulting from curet use. Specimens treated by contact mode, Group 3 and 4 featured surface changes not observed in controls such as charring, randomly distributed pitting and crater formation, and melting down of the tooth material and calculus. Specimens treated by non-contact mode, Group 5 and 6 featured similar surface changes observed in contact mode. However, the differences between contact and non-contact groups not significant. Specimens treated by contact mode with water irrigation, Group 7 and 8 featured slight surface change compared to other groups.

The results suggested that Nd: YAG laser did not completely remove the subgingival calculus but was possible the application as adjunctive method.