Treatment of periodontal pockets with a diode laser

Influence of different treatment approaches on the removal of early plaque biofilms and the viability of SAOS2 osteoblasts grown on titanium implants

The aim of the present study was to evaluate the influence of different treatment approaches on: (1) the removal of early plaque biofilms grown on titanium implants, and (2) the biocompatibility of the instrumented implant surfaces. Five volunteers wore acrylic splints with sand-blasted and acid-etched titanium discs for 24 h to build up supragingival plaque. A total of 80 specimens were randomly assigned to the following groups: (1) an Er:YAG laser (100 mJ/pulse, 10 Hz) (Y), (2) an ultrasonic system (U), (3) plastic curettes and rinsing with chlorhexidine digluconate (P), or (4) unworn titanium discs (C). Autoclaved specimens were incubated with SAOS2 cells for three days. The following parameters were measured: treatment time (T), residual plaque biofilm (RPB) and clean implant surface (CIS) areas (%), and mitochondrial cell activity (MA) (counts/s). Statistical analysis within and between groups revealed the following mean scores (+/-SD): RPB areas: P (61.1+/-11.4)>U (36.8+/-4.5)>Y (5.8+/-5.1); CIS areas: Y (94.2+/-5.1)>U (63.2+/-4.5)>P (38.9+/-11.2); T: Y (5.6+/-1.2)>U (2.4+/-0.5)>P (2.3+/-0.5); MA: C (1.528.636+/-188.371)>U (831.594+/-370.228)>Y (678.250+/-367.902)>P (144.105+/-120.961). Within the limits of the present study, it may be concluded that Y seems to be most suitable for the removal of supragingival early plaque biofilms grown on SLA titanium implants, and (2) all treatment procedures failed to restore the biocompatibility of previously-contaminated SLA titanium surfaces.

Clinical efficacy of semiconductor laser application as an adjunct to conventional scaling and root planing

BACKGROUND AND OBJECTIVES

The aim of the in vitro study was to examine the clinical efficacy of semiconductor laser periodontal pocket irradiation as an adjunct to conventional scaling and root planing.

MATERIALS AND METHODS

Twenty-two healthy patients with a need of periodontal treatment (15 women, 7 men, mean age 45.0 +/- 10.8 years) with at least four teeth in all quadrants, were included. All of them underwent a conventional periodontal treatment including scaling and root planing. Using a split mouth design, two randomly chosen quadrants (one upper and the corresponding lower one) were subsequently treated with an 809 nm GaAlAs laser operated at a power output of 1.0 Watt using a 0.6 mm optical fiber. The teeth in the control quadrants were rinsed with saline. The clinical outcome was evaluated by means of plaque index (PI), gingival index (GI), bleeding on probing (BOP), sulcus fluid flow rate (SFFR), Periotest (PT), probing pocket depth (PPD), and clinical attachment loss (CAL) at baseline and at 3 months after treatment. A total of 492 teeth in both groups were evaluated and differences between the laser and the control teeth were analyzed using the Wilcoxon test (P < 0.05).

RESULTS

Teeth treated with the laser revealed a significantly higher reduction in tooth mobility, pocket depth, and clinical attachment loss. Twelve percent of the teeth in the laser group showed an attachment gain of 3 mm or more, compared to 7% in the control group. An attachment gain of 2-3 mm was found in 24% of the teeth in the laser group and 18% in the control group. No significant group differences, however, could be detected for the plaque index, gingival index, bleeding on probing, and the sulcus fluid flow rate.

CONCLUSIONS

The higher reduction in tooth mobility and probing depths is probably not predominantly related to bacterial reduction in the periodontal pockets but to the de-epithelization of the periodontal pockets leading to an enhanced connective tissue attachment. The application of the diode laser in the treatment of inflammatory periodontitis at the irradiation parameters described above is a safe clinical procedure and can be recommended as an adjunct to conventional scaling and root planing.

Light-induced modulation of Porphyromonas gingivalis growth

The bacterium Porphyromonas gingivalis is a clinically significant agent in periodontitis, a disease for which there is no definitive cure. Several groups have attempted to kill this bacterium using low levels of light in the absence of a photosensitizer, with conflicting results. We hypothesize that it is not possible to kill P. gingivalis by targeting endogenous porphyrins for a photochemical reaction. We demonstrated that irradiation of P. gingivalis with 455 or 625 nm light emitting diodes did not induce a photochemical killing of the cultures. Controlled temperature experiments indicate that irradiation at either wavelength did not significantly impact the growth of P. gingivalis cultures, as compared to non-irradiated controls. Rather, the irradiation caused a temperature increase in the growth medium, which altered the growth of the cultures. These results indicate that heat-induced killing of P. gingivalis could be the mechanism behind successful irradiation experiments with this bacterium.

Lasers in surgical periodontics and oral medicine

Surgical lasers rapidly are becoming part of the periodontal armamentarium. This article discusses the different lasers that are suitable for use on the soft tissues of the periodontium. Various laser-assisted periodontal surgical procedures and laser treatment of diseases of the oral mucosa are discussed.

Microbial reduction in periodontal pockets under exposition of a medium power diode laser: An experimental study in rats

BACKGROUND AND OBJECTIVE

This work evaluates the application of a 810 nm diode laser operating in the range of 400-1,200 mW for bacterial reduction at periodontal treatment. The aim of this study is to examine the immediate effect of the diode medium power laser in reducing the bacterial concentration at periodontal pockets induced in Wistar rats.

STUDY DESIGN/MATERIALS AND METHODS

Two bacterial collections were performed on each animal. Microbiological samples were collected before and immediately after laser irradiation. In each group of laser power, eight animals were used, totaling 40 animals.

RESULTS

The initial and the final bacterial count revealed that laser irradiation induces considerable bacterial elimination, especially for Prevotella sp, Streptococcus beta-hemolitico, Fusobacterium sp, Pseudomonas sp.

CONCLUSIONS

Our results indicate that this laser can constitute an alternative device to traditional infrared systems for bacterial reduction, with some advantage when economical and practical standpoints are considered.

Lasers for initial periodontal therapy

With a greater understanding of the components that initiate the host into the downward spiral of periodontal disease, the clinician must look for better treatment and therapy options. Clinical observations and studies show good results, making incorporation of the laser into the first phase of nonsurgical periodontal therapy an excellent choice.

The biologic rationale for the use of lasers in dentistry

Dentists have a variety of wavelengths to choose from when purchasing a laser. Each wavelength has a unique interaction with the target tissues of the oral cavity. This article gives a rationale, grounded in sound biologic principles, for the use of different wavelengths in the oral cavity. Advantages and disadvantages of the various wavelengths for specific procedures are discussed.

Clinical applications of lasers during removable prosthetic reconstruction

The successful construction of removable full and partial dentures depends mainly on the preoperative evaluation of the supporting hard and soft tissue structures and their proper preparation. Stability, retention, function, and esthetics of removable prostheses may be enhanced by proper laser manipulation of the soft tissues and underlying osseous structure. Compared with conventional techniques, laser treatment has many advantages. More predictable postoperative healing results and shortened treatment time may be achieved when lasers are integrated into the treatment plan for construction of removable prosthetic devices.

Healing of intrabony defects following surgical treatment with or without an Er:YAG laser

AIM

The aim of this controlled, parallel design clinical study was to compare the healing of intrabony periodontal defects following treatment with access flap surgery with and without debridement with an Er:YAG laser.

METHODS

Twenty-three patients each of whom exhibited one deep intrabony defect were randomly treated with either access flap surgery followed by root surface and defect debridement using an Er:YAG laser (KEY3) (160 mJ, 10 Hz) (test), or with access flap surgery followed by root surface and defect debridement using hand and ultrasonic instruments (control). The following clinical parameters were recorded at baseline and at 6 months: plaque index; gingival index; bleeding on probing; probing depth (PD); gingival recession; and clinical attachment level (CAL). The primary outcome variable was CAL. No statistically significant differences between the groups were found at baseline.

RESULTS

No serious adverse events were observed after any of the treatments. The results have shown that in the test group the PD decreased from 7.8+/-1.3 to 4.1+/-1.3 mm (p<0.001) and the CAL changed from 9.8+/-2.9 to 7.2+/-2.5 mm (p<0.001). In the control group the PD decreased from 7.8+/-0.8 to 4.6+/-1.6 mm (p<0.001) and the CAL changed from 9.2+/-1.2 to 7.7+/-1.6 mm (p<0.01). The test group displayed a higher tendency for CAL gain, although this tendency did not prove to be statistically significant.

CONCLUSION

Within the limits of the present study, it can be concluded that: (i) at 6 months following treatment both therapies led to significant improvements of the investigated clinical parameters, and (ii) an Er:YAG laser may represent a suitable alternative for defect and root surface debridement in conjunction with periodontal surgery.

Clinical evaluation of an Er:YAG laser for nonsurgical treatment of peri-implantitis: a pilot study

The aim of this controlled, parallel design clinical study was to compare the effectiveness of an Er:YAG laser (ERL) to that of mechanical debridement using plastic curettes and antiseptic therapy for nonsurgical treatment of peri-implantitis. Twenty patients with moderate to advanced peri-implantitis lesions were randomly treated with either (1) an ERL using a cone-shaped glass fiber tip at an energy setting of 100 mJ/pulse and 10 pps (ERL), or (2) mechanical debridement using plastic curettes and antiseptic therapy with chlorhexidine digluconate (0.2%) (C). The following clinical parameters were measured at baseline, 3 and 6 months after treatment by one blinded and calibrated examiner: Plaque index (PI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR) and clinical attachment level (CAL). At the baseline examination, there were no statistically significant differences in any of the investigated parameters. Mean value of BOP decreased in the ERL group from 83% at baseline to 31% after 6 months (P < 0.001) and in the C group from 80% at baseline to 58% after 6 months (P < 0.001). The difference between the two groups was statistically significant (P < 0.001, respectively). The sites treated with ERL demonstrated a mean CAL change from 5.8 +/- 1 mm at baseline to 5.1 +/- 1.1 mm (P < 0.01) after 6 months. The C sites demonstrated a mean CAL change from 6.2 +/- 1.5 mm at baseline to 5.6 +/- 1.6 mm (P < 0.001) after 6 months. After 6 months, the difference between the two groups was statistically not significant (P > 0.05). Within the limits of the present study, it was concluded that (i) at 6 months following treatment both therapies led to significant improvements of the investigated clinical parameters, and (ii) ERL resulted in a statistically significant higher reduction of BOP than C.

Phototoxic Effect of Visible Light on Porphyromonas gingivalis and Fusobacterium nucleatum: An In Vitro Study¶†

The antibacterial effect of visible light irradiation combined with photosensitizers has been reported. The objective of this was to test the effect of visible light irradiation without photosensitizers on the viability of oral microorganisms. Strains of Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus mutans and Streptococcus faecalis in suspension or grown on agar were exposed to visible light at wavelengths of 400-500 nm. These wavelengths are used to photopolymerize composite resins widely used for dental restoration. Three photocuring light sources, quartz-tungsten-halogen lamp, light-emitting diode and plasma-arc, at power densities between 260 and 1300 mW/cm2 were used for up to 3 min. Bacterial samples were also exposed to a near-infrared diode laser (wavelength, 830 nm), using identical irradiation parameters for comparison. The results show that blue light sources exert a phototoxic effect on P. gingivalis and F. nucleatum. The minimal inhibitory dose for P. gingivalis and F. nucleatum was 16-62 J/cm2, a value significantly lower than that for S. mutans and S. faecalis (159-212 J/cm2). Near-infrared diode laser irradiation did not affect any of the bacteria tested. Our results suggest that visible light sources without exogenous photosensitizers have a phototoxic effect mainly on Gram-negative periodontal pathogens.

Therapeutic ratio quantifies laser antisepsis: Ablation ofPorphyromonas gingivalis with dental lasers

BACKGROUND AND OBJECTIVES

It is established that both pulsed Nd:YAG (1,064 nm) and continuous diode (810 nm) dental lasers kill pathogenic bacteria (laser antisepsis), but a quantitative method for determining clinical dosimetry does not exist. The purpose of this study was to develop a method to quantify the efficacy of ablation of Porphyromonas gingivalis (Pg) in vitro for two different lasers.

STUDY DESIGN/MATERIALS AND METHODS

The ablation thresholds for the two lasers were compared in the following manner. The energy density was measured as a function of distance from the output of the fiber-optic delivery system. Pg cultures were grown on blood agar plates under standard anaerobic conditions. Blood agar provides an approximation of gingival tissue for the wavelengths tested in having hemoglobin as a primary absorber. Single pulses of laser energy were delivered to Pg colonies and the energy density was increased until the appearance of a small plume was observed coincident with a laser pulse. The energy density at this point defines the ablation threshold. Ablation thresholds to a single pulse were determined for both Pg and for blood agar alone.

RESULTS

The large difference in ablation thresholds between the pigmented pathogen and the host matrix for pulsed-Nd:YAG represented a significant therapeutic ratio and Pg was ablated without visible effect on the blood agar. Near threshold the 810-nm diode laser destroyed both the pathogen and the gel.

CONCLUSIONS

Clinically, the pulsed Nd:YAG may selectively destroy pigmented pathogens leaving the surrounding tissue intact. The 810-nm diode laser may not demonstrate this selectivity due to its greater absorption by hemoglobin and/or longer pulse duration.

In vivo and in vitro effects of an Er:YAG laser, a GaAlAs diode laser, and scaling and root planing on periodontally diseased root surfaces: a comparative histologic study

BACKGROUND AND OBJECTIVES

The aim of the present histologic study was to compare the in vivo and in vitro effects of an erbium: yttrium, aluminum, and garnet (Er:YAG) laser (ERL), combined with a fluorescent calculus detection system, a diode laser (DL) and scaling and root planing (SRP) on periodontally diseased root surfaces.

STUDY DESIGN/MATERIALS AND METHODS

Twenty-four single rooted teeth, considered for extraction due to severe periodontal destruction, were included in the study. Prior to extraction all mesial root surfaces were randomly assigned to the following treatment groups: (1) ERL combined with a calculus detection system with fluorescence induced by 655 nm InGaAsP DL radiation (160 mJ/pulse and 10 pulses/second under water irrigation) (ERL), or (2) GaAlAs DL (1.8 W, pulse/pause relation 1:10), or (3) SRP using hand instruments. Immediately after extraction, all distal root surfaces were treated with the same instruments under standardized conditions. For light microscopic investigation, a plastic embedding technique was used to cut the undecalcified roots into 30 microm thick crossections. The following parameters were recorded by on blind examiner: remaining debris, root surface morphology, and thermal side effects.

RESULTS

Root surfaces instrumented with both, ERL in vivo and DL in vitro exhibited no detectable surface alterations. In contrast, ERL scaling in vitro and SRP in vivo/in vitro produced superficial microchanges in root cementum. However, irradiation with DL in vivo caused severe damages to the root surface (i.e., crater formation). There were no signs of thermal side effects in all laser treated groups. ERL provided subgingival calculus removal on a level equivalent to that provided by SRP. DL was unsuitable for calculus removal, since macroscopic inspection revealed the presence of large amounts of subgingival calculus.

CONCLUSIONS

The present in vivo results showed that (i) ERL, combined with a fluorescent calculus detection system, provided a selective subgingival calculus removal on a level equivalent to that provided by SRP, and (ii) DL, using this power output, was unsuitable for calculus removal and altered the root surface in an undesirable manner.

Lethal photosensitization of periodontal pathogens by a red-filtered Xenon lamp in vitro

BACKGROUND

The ability of Helium-Neon (He-Ne) laser irradiation of a photosensitizer to induce localized phototoxic effects that kill periodontal pathogens is well documented and is termed photodynamic therapy (PDT).

OBJECTIVES

We investigated the potential of a conventional light source (red-filtered Xenon lamp) to activate toluidine blue O (TBO) in vitro and determined in vitro model parameters that may be used in future in vivo trials.

MATERIALS AND METHODS

Porphyromonas gingivalis 381 was used as the primary test bacterium.

RESULTS

Treatment with a 2.2 J/cm2 light dose and 50 micro g/ml TBO concentration resulted in a bacterial kill of 2.43 +/- 0.39 logs with the He-Ne laser control and 3.34 +/- 0.24 logs with the lamp, a near 10-fold increase (p = 0.028). Increases in light intensity produced significantly higher killing (p = 0.012) that plateaued at 25 mW/cm2. There was a linear relationship between light dose and bacterial killing (r2 = 0.916); as light dose was increased bacterial survival decreased. No such relationship was found for the drug concentrations tested. Addition of serum or blood at 50% v/v to the P. gingivalis suspension prior to irradiation diminished killing from approximately 5 logs to 3 logs at 10 J/cm2. When serum was washed off, killing returned to 5 logs for all species tested except Bacteroides forsythus (3.92 +/- 0.68 logs kill).

CONCLUSIONS

The data indicate that PDT utilizing a conventional light source is at least as effective as laser-induced treatment in vitro. Furthermore, PDT achieves significant bactericidal activity in the presence of serum and blood when used with the set parameters of 10 J/cm2, 100 mW/cm2 and 12.5 micro g/ml TBO.

Temperature changes induced by 809-nm GaAlAs laser at the implant-bone interface during simulated surface decontamination

The aim of the study was to investigate temperature changes at the implant-bone interface during simulated implant surface decontamination with a 809-nm gallium-aluminium-arsenid (GaAlAs) semiconductor laser. Stepped cylinder implants with a diameter of 3.8 mm and a length of 11 mm with two different surfaces (sand-blasted and acid etched, and hydroxyapatite-coated) were inserted into bone blocks cut from freshly resected pig femurs. Access holes of 0.5 mm were drilled into the bone, to allow K-type thermocouples to contact periimplant bone in different parts of the cavity. An artificial periimplant bone defect provided access for laser irradiation in the coronal third. A 600-micrometer optic fiber was used at a distance of 0.5 mm from the implant surface. Power output varied between 0.5 and 2.5 W in the continuous wave mode. The bone block was placed into a 37 degrees C water bath in order to simulate in vivo thermal conductivity and diffusitivity of heat. Temperature elevations during irradiation were registered for a period of 120 s. In mean, the critical threshold of 47 degrees C was exceeded after 9.0 s at 2.5 W, 12.5 s at 2.0 W, 18.0 s at 1.5 W and 30.5 s at 1.0 W. Surface characteristics did not have a significant effect on temperature elevations. In an energy-dependent manner, implant surface decontamination with an 809-nm GaAlAs laser must be limited in time to allow the implant and bone to cool down. Clinical guidelines are presented to avoid tissue damage.

Effect of simulated CO2 and GaAlAs laser surface decontamination on temperature changes in Ti-plasma sprayed dental implants

BACKGROUND AND OBJECTIVE

To investigate and compare temperature elevations at the implant-bone interface during simulated implant surface decontamination with a CO2 and a GaAlAs laser.

STUDY DESIGN/MATERIALS AND METHODS

Stepped cylinder implants (Frialit 2) Friadent GmbH, Mannheim, Germany) with a Titanium plasma sprayed surface were inserted into bone blocks cut from pig femurs. An artificial periimplant bone defect provided access for laser irradiation in the coronal third. Both lasers were operated at 1.0-2.5 W in the cw-mode. The bone block was placed into a 37 degrees C water bath in order to simulate in vivo thermal conductivity and diffusitivity of heat. K-type thermocouples connected to a digital meter were used to register temperature changes at the periimplant bone.

RESULTS

In mean, the critical threshold of 47 degrees C was exceeded after 8 seconds at a power output of 2.5 W, 13 seconds at 2.0 W, 18 seconds at 1.5 W, and 42 seconds at 1.0 W with the GaAlAs laser and 15 seconds (2.5 W), 23 seconds (2.0 W), 35 seconds (1.5 W), and 56 seconds (1.0 W) with the CO2 laser. At equal energy fluence, GaAlAs laser irradiation induced significantly higher temperature elevations than CO2 laser irradiation.

CONCLUSIONS

In an energy dependent manner implant surface decontamination with both laser types must be limited in time to allow the implant and bone to cool down. Clinical guidelines are presented to avoid tissue damage.

Lasers in periodontics

Publicity about the use of lasers in dentistry has generated considerable interest in both professional and lay audiences. The purpose of this report is to provide information for members of the dental profession about the current and potential application of laser technology to periodontal practice. This report was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology.

Antimicrobial effects of mechanical debridement

Self-performed plaque removal using manual or powered toothbrushes and interdental cleaning devices is improved in subjects that have received oral hygiene instructions. Personal oral hygiene coupled with regular professional supragingival debridement may further improve the level of plaque control but still fails to achieve a completely plaque-free dentition. Both patient-performed and professional supragingival plaque removal has an effect on subgingival microbiota that is limited to the marginal 3 mm of the periodontal pocket. At sites with 4 mm or more of probing depth, only subgingival scaling leads to a significant reduction of the bacterial load. The subgingival microflora can be further reduced by pocket elimination surgery. Due to the sequence of bacterial recolonization that occurs following mechanical debridement, the level of periodontal pathogens such as B. forsythus, P. gingivalis and T. denticola may be reduced for several months. Mechanical debridement also influences the patient's immune system response, resulting in antibody titers and avidity against periodontal pathogens. As a basis for the restoration and maintenance of periodontal health, repeated subgingival debridement, as performed in supportive periodontal therapy, can reduce the number and proportions of periodontopathogenic bacteria in subgingival plaque. However, intensive subgingival scaling and root planing should be avoided in sites that probe less than 3 mm, as this is likely to traumatize the periodontium and cause attachment loss.

Effect of gallium arsenide diode laser on human periodontal disease: a microbiological and clinical study

BACKGROUND AND OBJECTIVE

The present study is aimed to describe short-term results on selected microbiological and clinical parameters obtained by treatment with soft laser in conjunction with methylene blue and/or mechanical subgingival debridement in human periodontal disease.

STUDY DESIGN/MATERIALS AND METHODS

Ten patients, in whom each dental quadrant was randomly designated to receive one of four types of treatment procedures, were included in the study. Groups of quadrants received: scaling/root planing (SRP); laser application (L); SRP combined with L (SRP/L); oral hygiene instructions (OHI). Four single rooted teeth (one in each quadrant), having an interproximal site with a probing depth of 4 mm mesio-buccally, were selected in each patient. The selected teeth were first assessed for microbiological (one site/tooth) and then for clinical variables (six sites/tooth). Supragingival irrigation with methylene blue was performed prior to laser application. The microbiological (proportions of obligate anaerobes) and clinical measurements (plaque and gingival indices, bleeding on probing, probing pocket depth) were evaluated over a period of 32 days.

RESULTS

Only the SRP/L and SRP groups provided significant reductions in the proportions of obligate anaerobes before and after treatments with no significant differences in between. Parallel to the microbiological changes, both SRP/L and SRP resulted in similar clinical improvements, whereas L alone revealed a limited effect similar to OHI.

CONCLUSION

Within the limits of this study, methylene blue/soft laser therapy provided no additional microbiological and clinical benefits over conventional mechanical debridement.

Effects of Nd:YAG laser irradiation on cultured human gingival fibroblasts

BACKGROUND AND OBJECTIVE

The Nd:YAG laser has been proposed to apply in minor soft tissue surgery, including various periodontal procedures. However, little information is available regarding the direct effect of Nd:YAG laser on gingival fibroblasts, which play an important role in the early healing processes of periodontal repair.

STUDY DESIGN/MATERIALS AND METHODS

Nd:YAG laser irradiation was performed in pulsed mode on human gingival fibroblasts, which was derived from healthy human gingiva by an explant method. The size of laser diode was 400 microm in diameter. The parameters in laser delivery were pulse energy (50-150 mJ), power output (1.0-3.0 W), pulse rate (10-30 pps), and fixed duration of irradiation (10 seconds). The cell cultures were analysed by cytomorphologic examination under phase-contrast and scanning electron microscope. The vitality was also examined with the help of MTT staining.

RESULTS

The area of laser damage on cell culture was circular in shape, with diameter beyond the size of laser diode. By scanning electron microscopy, we observed the cellular damage of cultured gingival fibroblasts induced by Nd:YAG laser irradiation, comparable with the progressive increased power settings. The cytomorphologic changes ranged from disappearance of cellular boundary, loss of identifiable cellular nucleus, and finally cell contraction and vacuolization. Significant decrease in cellular vitality (14% approximately 44%) after laser treatment with irradiation distance of nearly contact was noted. However, 2 mm defocusing irradiation with the same power settings did not significantly decrease cellular vitality.

CONCLUSION

Our study demonstrated the cell damaging effects of Nd:YAG laser, ranging from degeneratively cytomorphologic change to cell death, on the cultured human gingival fibroblasts. It provided the dentist a chance to understand the potential hazard of laser application in periodontal treatment. If the energy output is enough for the clinical purposes, Nd:YAG laser with lower pulse energy and corresponding pulse rate should be selected to minimize the damage on adjacent soft tissue.

Effects of diode and Nd:YAG laser irradiation on titanium discs: a scanning electron microscope examination

BACKGROUND

Dental lasers have been recommended for uncovering submerged implants as well as decontaminating implant surfaces when treating peri-implantitis. The aim of this study was to show the possible alterations in titanium disc surfaces using an Nd:YAG or a diode laser.

METHODS

Three different titanium discs were used (sandblasted, titanium plasma-sprayed [TPS], and hydroxyapatite [HA] coated) to determine the effects of laser irradiation on these surfaces using a scanning electron microscope (SEM). The discs were either irradiated with a pulsed Nd:YAG laser with a contact handpiece and power settings of 2.0, 4.0, and 6.0 W or with a diode laser at 5.0, 10.0, and 15.0 W power settings and continuous wave (cw) in the contact handpiece. Irradiated areas were compared with control titanium sites which were not lased. The specimens were prepared for SEM examination after the disc irradiation.

RESULTS

The SEM examination demonstrated extensive melting in all of the Nd:YAG laser irradiated areas. Damage was seen in all TPS- and HA-coated discs even at the lowest power setting. Loss of porosity, coating microfractures, and a relatively smooth surface were observed. In contrast, the diode laser did not cause any damage or modify the disc surface. Regardless of the power setting, there was no visible difference between lased and non-lased surfaces after cw irradiation with the diode laser.

CONCLUSIONS

From these findings, it was concluded that the diode laser (980 nm) does not damage titanium surfaces, which should be of value when uncovering submerged implants and treating peri-implantitis.

Effects on oral soft tissue produced by a diode laser in vitro

BACKGROUND AND OBJECTIVES

This investigation determined incision characteristics and soft-tissue damage resulting from standardized incisions using a wide range of laser modes and parameters of a diode laser at 810 nm.

STUDY DESIGN/MATERIALS AND METHODS

Histologic examinations were performed to verify vertical and horizontal tissue damage as well as incision depth and width.

RESULTS

Incision depth and width correlated strongly with average powers, but not with laser parameters or the used tips. No laser damage was visible to the naked eye in the bone underlying the incisions in the range between 0.5-4.5 W.

CONCLUSION

The remarkable cutting ability and the tolerable damage zone clearly show that the diode laser is a very effective and, because of its excellent coagulation ability, useful alternative in soft-tissue surgery of the oral cavity.

Diode laser (980 nm) in oral and maxillofacial surgical procedures: clinical observations based on clinical applications

OBJECTIVE

The aim of this study was to examine the wound healing of soft tissue after the application of a diode laser (980 nm) in oral surgical procedures.

SUMMARY BACKGROUND DATA

Like the CO2 laser, the diode laser can be used for soft tissue surgery without extensive experience in the field of oral surgical.

METHODS

A diode laser was used to treat a variety of oral soft tissue lesions in 22 patients. The oral surgical procedures included removal of soft tissue tumors, frenectomies, excision of gingival hyperplasias, vestibuloplasties, hemangioma removal, and periimplant soft tissue surgery. The laser was used in both pulsed and continuous modes, with and without contact to the tissue. Intraoperative and postoperative clinical observations are reported.

RESULTS

Our preliminary clinical findings include sufficient hemostasis and precise incision margin with all of the surgical procedures. The coagulation properties, associated with the use of a diode laser, were particularly beneficial during removal of vascular lesions. The postoperative advantages, i.e., lack of swelling, bleeding, pain or, scar tissue formation, and the good wound healing were observed in all of the clinical applications and were dependent only on the laser physical parameters used.

CONCLUSIONS

The clinical application of the diode (980 nm) laser in oral and maxillofacial surgical procedures seems to be of beneficial effect for daily practice.