By Dr. Robert J Miller

(This article originally appeared in the September/October 2006 issue of Dental Practice) [Download PDF]

Instrumentation for dental implant procedures has not changed significantly over the last few decades. Most of these procedures share one parameter in common; they are primarily resective in nature. When tissue is traumatized, it goes through an inflammatory cascade which results in edema, erythema and discomfort for the patient. A period of tissue remodelling then occurs in which the production of matrix metallo-proteinases (collagenases, elastases, and gelatinases) occurs. These enzymes are the primary inducers of both soft and hard tissue remodelling. Crestal bone remodelling around implants is one result of the action of these compounds. The loss of peri-implant osseous support may cause the collapse of the interdental papilla, resulting in compromised gingival display in the aesthetic zone.

A paradigm changing modality has recently become available for use in oral implantology. The Er,Cr;YSGG laser (Waterlase, Biolase Technologies) has been used to treat peri-implant tissue for the past 8 years. The hydrophotonic properties of the 2780nm wavelength targets tissue along a cell layer rather than in a tissue zone. Studies indicate a cellular action zone of only 8-15 microns, leaving adjacent tissue undisturbed. This results in pure tissue ablation rather than coagulation. The absence of tissue damage eliminates the precursors of the inflammatory cascade that may affect tissue as far as 10mm from the surgical site. Tissues can then go directly to regrowth and regeneration.

Peri-implant tissue differs considerably from periodontal tissue. There is no direct attachment of periodontal fibres to the implant surface. In addition, there is a larger volume of collagen and smaller number of fibroblasts in peri-implant tissue. This makes the reparative potential much lower for peri-implant tissue. When the hemi-desmosomal attachment to the neck of the implant is disturbed, it tends to scar down rather than reattach to the previous position on the implant surface. Secondary uncovering of the implant, whether by flap or tissue punch, removes the healed attachment apparatus. The attachment is reestablished more apically, which ultimately results in crestal bone remodelling. Healing time for this pathway may be several months. If final impressions are taken prior to full tissue maturity, gingival recession may occur leading to uneven gingival margins and loss of papillary form. The stability and health of this attachment apparatus is of prime concern in the aesthetic zone.

The Er,Cr;YSGG laser can be used to remove gingival tissue at the time of implant uncovering (Figure 1) and has been used by the author on more than 200 patients over 6 years. This is an erbium based laser, and as a result there is a low thermal coefficient, with this coefficient measured by the degree of temperature rise within the target issue. Erbium-based lasers (YAG, YSGG) are considered cool lasers, and are preferred for oral implantology procedures. This prevents burning, charring, and coagulation at the site of interaction and is safe to use directly on titanium surfaces (Figure 2).

No anaesthetic is necessary for most of these procedures and the soft tissue may be sculpted for proper emergence profile. A healing abutment or provisional crown may be placed to start the process of papilla regrowth (Figure 3). The emergence profile is sculpted to a circumference slightly smaller than the healing abutment. A significantly shorter healing time has been observed using the YSGG laser with the added benefits of decontamination and biostimulation of the surrounding tissue (Figure 4).

At the time of placement of the final contoured abutment, a radiograph is exposed and the implant/abutment interface is measured (Figure 5). The distance to the crest is determined and the patient is followed for up to one year. A new radiograph is exposed and the distance to the crest is measured and compared to the time of abutment placement (Figure 6). The lack of crestal change is clear evidence of the reduction of inflammatory infiltrate and resultant crestal bone remodelling. This is a significant advantage in the aesthetic zone where maintenance of the interdental papillae around dental implants is problematic.

When compared to traditional resective techniques, tissue stability appears to be enhanced when lasers are employed (Figure 7). In the author’s study of uncovering over 500 implants with the YSGG laser, preservation of interdental papillae was found to be more predictable and crestal bone remodelling was significantly reduced or eliminated. The YSGG laser can be used for many other hard and soft tissue procedures in oral implantology including osseous recontouring and the treatment of peri-implantitis. Lasers will play an increasingly important role in dental implant procedures.