Effect of the lasers used in periodontal therapy on the surfaces of restorative materials

The Effect of Periodontal Therapy on the Level of MMP-8 in Patients with Chronic Periodontitis

OBJECTIVE

 The complete removal of bacterial plaque and their endotoxins in deeper areas of periodontal pockets is often difficult to achieve with conventional methods such as periodontal pocket curettage. An alternative to these methods that recently gained popularity in periodontology is the diode laser, with its antibacterial effect, angiogenesis promotion as advantages.

MATERIALS AND METHODS

 This study included 100 patients diagnosed with chronic periodontitis, with periodontal pockets up to 6 mm, and who were divided into two groups: patients treated with basic therapy and diode laser application, and patients treated with basic therapy and with flap surgery. The clinical periodontal evaluation was done before the treatment and 6 months after the treatment. Evaluation of matrix metalloproteinase (MMP)-8 as an inflammatory indicator in gingival exudate was done with dipstick immunoassay test before the treatment and 6 months later.

RESULTS

 This study showed a more pronounced improvement of periodontal clinical parameters, as well as a decrease in MMP-8 values in gingival exudate in the laser-treated group compared with the surgically treated group.

CONCLUSION

 The results of this study are encouraging for the use of the diode laser as a noninvasive method in the treatment of periodontal pathologies.

Can We Determine an Appropriate Timing to Avoid Thermal Pulp Hazard During Gingivectomy Procedure? An In Vitro Study with Diode Laser

Objective: Diode laser (DL) is a frequently preferred tool for soft tissue incision and ablation in oral surgery. The aim of this study was to find the most effective irradiation time protocol to avoid potential harmful temperature rise in pulp during DL-assisted gingivectomy. Materials and methods: Ninety human freshly extracted teeth (30 anterior, 30 premolar, and 30 molar) were irradiated using a 940 nm DL with power output of 1 and 2 W and exposure time of 10, 20, 30, 40, 50, and 60 sec per specimen. Intrapulpal temperature was evaluated with thermocouple. Additionally, the effect of dark deposits on root surface for intrapulpal temperature rise was investigated. Temperature differences with every 10 sec were evaluated for three different teeth types, and statistical analyses were performed. Results: Anterior and premolar teeth exceeded the threshold values earlier than molar teeth for both 1 and 2 W. Despite the significant differences among the types of teeth, at 10 sec, temperature rise recorded for all types of teeth was below the critical value of 5.6°C, which cause pulp damage. Dark deposits on teeth surface boosted thermal effect of DLs (p < 0.01). Conclusions: Gingivectomy with DLs at 1 W on anterior, premolar, and molar teeth for 20, 40, and 60 sec, respectively, generates acceptable temperature rise; however, it should be <10, 20, and 40 sec at 2 W, respectively. Especially in the anterior teeth, DLs should be performed with caution to avoid pulp damage.

Characterization of the transmission behavior of dental filling materials and cements for the diode lasers' and the Nd:YAG laser's wavelengths

OBJECTIVES

Diode lasers and the Nd:YAG laser are used in periodontal therapy and soft tissue surgery. Dental filling materials or cements might be inadvertently damaged. The underlying mechanism of the damage is based on the dental material's specific transmission and thus absorption behavior.

MATERIALS AND METHODS

Twenty-four material representatives for composites, glass ionomer cements and other material classes (e.g., compomer) were processed to 100 μm and 200 μm planar specimens and spectroscopically measured for their collimated transmission in the photo spectrometer Varian Cary 5000. The (1) mean intensity of transmitted light was determined for the laser wavelengths of interest (810 nm, 940 nm, 980 nm, 1,064 nm) and used to calculate the (2) absorption lengths.

RESULTS

The (1) mean intensity of transmitted light ranged between 9.51 % (Panavia F 2.0 for 810 nm) and 96.79% (Artegral Cem for 1,064 nm) for the composite specimens (100 μm) and was-with few exceptions-near zero for the representatives of glass ionomer cement and the other material classes. The (2) absorption lengths were between 0.06 mm (Panavia F 2.0 for all wavelengths of interest) and 1.33 mm (Coltène Duo Cement Plus for 1,064 nm) for the composites and below or equal 0.15 mm (PermaCem for 1,064 nm) for the few representatives of glass ionomer cements and the other material classes with mean intensities of transmitted light, which were not near zero and thus permitted to calculate absorption lengths.

CONCLUSIONS

The transmission behavior varied between the different material classes and even within, albeit less pronounced. Composites generally showed the highest intensities of transmitted light and are thus least susceptible to surface damage by laser light (810 nm, 940 nm, 980 nm, 1,064 nm). The results can be used to improve and develop laser applications involving purposeful interactions between laser light and dental materials. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.