Effects of coaxial CO₂/Nd:YAG irradiation on periodontal wound healing

Abstract

This study evaluated a coaxial CO2/Nd:YAG laser used during periodontal surgery in mongrel dogs for the purpose of ablating the osseous portions of root surfaces to increase reattachment of soft tissue. Periodontal defects were produced with ligatures of orthodontic wire and elastics. The left mandibular osseous root surfaces were irradiated with a defocused, CW laser beam [power density (PD) = 42.46 W/cm2, energy density (ED) = 424.63 J/cm2]. The left maxillary osseous root surfaces were treated with a beam at twice the energy density [PD = 84.93 W/cm2, ED = 849.3 J/cm2]. The mandibular right quadrant received conventional surgery and the maxillary right quadrant served as the untreated control. Fourteen days after treatment, facial/lingual attached gingivae were scored for soft tissue adherence to bone. Laser irradiation at low ED did not improve soft tissue attachment when compared to conventional treatment. Higher ED irradiation produced significantly less attachment and increased tissue necrosis.

Laser Applications in Periodontology

“…Despite apparent benefits of lasers regarding patient compliance and clinical observation, there are no enough data to support that laser is associated with reduced scarring, which itself appears to be different according to the wavelength and extremely related to the energy density, and there are no enough data to support quicker healing associated with laser therapy [13]. Limited experimental animal studies [68,69] involving CO 2 ,Nd:YAG, diode lasers, or Er:YAG have evaluated the histological and immunohistochemical patterns of periodontal tissue healing following surgical and nonsurgical periodontal therapy. Sculean et al [70] and Yukna et al [71] reported healing response of intrabony defects after open flap surgery or treatment using a laser-assisted new attachment procedure in humans using Er:YAG and Nd:YAG lasers, respectively.…”

The impact of laser application on periodontal and peri‐implant wound healing

“…One study attempted to evaluate periodontal wound healing in dogs after irradiation using a coaxial CO 2 ⁄ Nd:YAG laser (5). Chronic periodontal defects were experimentally induced at the furcation and interproximal areas of either maxillary or mandibular premolars and molars.…”

“…The most commonly used lasers in this group are the gallium‐aluminum‐arsenide (GaAlAs) laser (810 nm) and the indium‐gallium‐arsenide‐phosphide (InGaAsP) laser (980 nm). Diode lasers operate in continuous wave and/or pulsed modes and are very effective for use in soft‐tissue applications with excellent effects of incision, hemostasis and coagulation (5). These specific wavelengths are well absorbed in hemoglobin and pigmented tissue (Fig.…”

“…So far, however, the principles of wound healing following either nonsurgical or surgical periodontal treatment procedures have only been reported for the CO 2 , Nd:YAG and Er:YAG lasers (Table 1). In particular, six experimental animal studies have evaluated the histological and immunohistochemical patterns of periodontal tissue healing following nonsurgical and surgical periodontal therapy in dogs (5, 16, 30, 58, 76, 100), and two human histological studies have reported on the healing of intrabony defects after open flap surgery or treatment using a laser‐assisted new attachment procedure (91, 102).…”

Lasers in periodontal therapy

“…Thus, to achieve osseous ablation by laser, higher power settings and longer exposure times are generally required, increasing the risk of collateral tissue damage. Over the last decade, numerous investigators have studied the effect of the COz laser (and to a lesser extent the Nd:YAG) on bone, but generally at energy densities greater than those suggested for soft tissue surgery (4,11,13,29,42,61,84,93). Three distinct histological zones may be delineated in laser-treated bone: a superficial char zone, an intermediate zone of nonvital heat-damaged bone featuring empty lacunae and a deep zone of normal bone (70,71).…”