Does a pulsed mode offer advantages over a continuous wave mode for excisional biopsies performed using a carbon dioxide laser?

Animal studies of excisional biopsies have shown less thermal damage when a carbon dioxide (CO(2)) laser (10.6 μm) is used in a char-free (CF) mode than in a continuous-wave (CW) mode. The authors' aim was to evaluate and compare clinical and histopathologic findings of excisional biopsies performed with CW and CF CO(2) laser (10.6 μm) modes. This prospective randomized controlled clinical trial included 60 patients with similar fibrous hyperplasias of the buccal plane willing to undergo excisional CO(2) laser biopsy. Patients were randomly allocated to the CW (5 W) or CF (140 Hz, 400 μs, 33 mJ) group. Duration of surgery, intra- and postoperative complications, and the width (micrometers) of the histopathologic collateral thermal damage zone were registered as primary outcome variables. Secondary outcome variables were pain (patients filled in a visual analog scale [VAS]) and analgesic intake (recorded by patients). The study group consisted of 36 women and 24 men with a median age of 50.5 years. Median durations of surgery were 74.5 seconds in the CW group and 83.5 seconds in the CF group. Intraoperative venous bleeding occurred in 16.7% of patients in the CW group and in 13.3% of patients in the CF group. Median areas of histopathologic collateral damage zones were similar in the CW group (166.5 μm) and the CF group (162.5 μm). There was no statistically significant difference between the VAS values of the 2 groups. Analgesic intake was recorded by 16.7% of patients in the CW group and by 6.7% of patients in the CF group (P = .23, not significant). No statistically significant correlation was found between areas of thermal damage zones and postoperative VAS scores. In contrast to previous animal studies, no significant difference was found in the widths of thermal damage zones between the CW and CF groups. The VAS values and analgesic intake were low in the 2 groups. The 2 CO(2) laser modes are appropriate for the excision of intraoral mucosal lesions. A safety border of at least 1 mm is recommended regardless of the laser mode used.

Suter VG ，Altermatt HJ ，Dietrich T ，Reichart PA ，Bornstein MM ... -  《-》

Pulsed versus continuous wave CO2 laser excisions of 100 oral fibrous hyperplasias: a randomized controlled clinical and histopathological study.

In experimental animal studies, pulsing the CO2 laser beam has been shown to reduce the thermal damage zone of excised oral mucosal tissue. However, there is still controversy over whether this is borne out under clinical conditions. To compare the outcome following excisional biopsies of fibrous hyperplasias using a pulsed (cf) versus a continuous wave (cw) CO2 laser mode regarding the thermal damage zone, duration of surgeries, intra- and postoperative complications, postoperative pain sensation, scarring and/or relapse during the initial 6 months. One hundred Swiss-resident patients with a fibrous hyperplasia in their buccal mucosa were randomly assigned to the cw mode (5 W) or the cf mode (140 Hz, 400 microseconds, 33 mJ, 4.62 W) group. All excisions were performed by one single oral surgeon. Postoperative pain (2 weeks) was recorded by visual analogue scale (VAS; ranging from 0 to 100). Intake of analgesics and postoperative complications were recorded in a standardized study form. The maximum width of the collateral thermal damage zone was measured (µm) in excision specimens by one pathologist. Intraoral photographs at 6-month follow-up examinations were evaluated regarding scarring (yes/no). Median duration of the excision was 65 seconds in the cw and 81 seconds in the cf group (P = 0.13). Intraoperative bleeding occurred in 16.3% of the patients in the cw and 17.7% of the cf group. The median value of the thermal damage zone was 161(±228) μm in the cw and 152(± 105) μm in the cf group (P = 0.68). The reported postoperative complications included swelling in 19% and minor bleeding in 6% without significant differences between the two laser modes. When comparing each day separately or the combined mean VAS scores of both groups between Days 1-3, 1-7, and 1-15, there were no significant differences. However, more patients of the cw group (25%) took analgesics than patients of the cf group (9.8%) resulting in a borderline significance (P = 0.04). Scarring at the excision site was found in 50.6% of 77 patients after 6 months, and more scars were identified in cases treated with the cf mode (P = 0.03). Excision of fibrous hyperplasias performed with a CO2 laser demonstrated a good clinical outcome and long-term predictability with a low risk of recurrence regardless of the laser mode (cf or cw) used. Scarring after 6 months was only seen in 50.6% of the cases and was slightly more frequent in the cf mode group. Based on the findings of the present study, a safety border of 1 mm appears sufficient for both laser modes especially when performing a biopsy of a suspicious soft tissue lesion to ensure a proper histopathological examination.

Suter VG ，Altermatt HJ ，Dietrich T ，Warnakulasuriya S ，Bornstein MM ... -  《-》

CO2 and diode laser for excisional biopsies of oral mucosal lesions. A pilot study evaluating clinical and histopathological parameters.

Suter VG ，Altermatt HJ ，Sendi P ，Mettraux G ，Bornstein MM ... -  《-》

A randomized controlled clinical and histopathological trial comparing excisional biopsies of oral fibrous hyperplasias using CO(2) and Er:YAG laser.

Suter VGA ，Altermatt HJ ，Bornstein MM 《-》

Comparison of conventional surgery and CO2 laser on intraoral soft tissue pathologies and evaluation of the collateral thermal damage.

Tuncer I ，Ozçakir-Tomruk C ，Sencift K ，Cöloğlu S ... -  《-》