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


OBJECTIVE
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.


METHODS
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).


RESULTS
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).


CONCLUSIONS
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.
Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland; Department of Oral Medicine & Pathology, King's College London Dental Institute, London, United Kingdom.
Valerie G A
VG
Suter
Hans Jörg
HJ
Altermatt
Thomas
T
Dietrich
Saman
S
Warnakulasuriya
Michael M
MM
Bornstein
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002921:Cicatrix / Q000209:etiology; D005260:Female; D005355:Fibrosis / Q000473:pathology / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D006965:Hyperplasia / Q000473:pathology / Q000601:surgery; D054020:Lasers, Gas / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology* / Q000601:surgery*; D010147:Pain Measurement; D010149:Postoperative Pain; D011183:Postoperative Complications; D016896:Treatment Outcome
oral mucosa; pain, postoperative bleeding; scar; thermal damage zone