This RCT aimed to compare both techniques regarding clinical outcomes, pain perception, patient satisfaction, and stability of the results. To the best of our knowledge, there are no published clinical trials to compare the outcomes of gingival depigmentation by ceramic soft tissue trimming bur with the surgical stripping technique.
The scalpel technique is still a gold standard in gingival depigmentation. The popularity of the scalpel technique is owed to its efficiency, affordability, and simplicity. However, this technique has the drawbacks of a bloody field of surgery, probable infections, and a high rate of recurrence(10–12). Cerabur was selected in this study as a novel and promising technique for gingival depigmentation that shares the affordability and ease of use of the surgical stripping technique with the additional benefit of good hemostasis and cleanliness of the operating field (7).
The study was conducted in a split-mouth fashion (13, 14). This design was selected to evade the inter-subject variables such as age, facial complexion, genetics, and environmental risk factors. The inter-subject variables could induce bias in the estimated treatment effect and the pain perception of the individual (15). The decision to employ the arches design over the quadrant design was to avoid color disparity in the same arch which might be dissatisfactory to the patient. Carry-over effects may induce bias in split-mouth RCTs(16). Consequently, in this study one dental arch of each patient was treated according to the assigned randomization and the opposing arch was not treated until the patient reported no pain (0 on VAS).
Periodontal pack placement is not mandatory. However, there are multiple benefits to applying a periodontal pack post-surgically including less post-operative pain score reported by the patients and slightly better healing (17, 18). Application of a periodontal pack after both procedures in accordance with previous studies (6, 7, 12, 19).
DOPI, as well as MI pigmentation indices, were both used to attain more accurate results as DOPI is based on the color intensity of the gingival pigmentation whereas MI is based on the extent and the distribution of the pigments. Previous studies have used two pigmentation indices for the same reason.(6, 20)
The results of the present study showed a statistically significant reduction in DOPI values in both groups from baseline. Gholami et al., 2018 compared surgical stripping and ErCr: YSGG (Erbium, chromium-doped yttrium, scandium, gallium, and garnet) Laser depigmentation and Negi et al., 2019 compared cerabur and diode laser depigmentation. They both reported a significant decrease in pigmentation indices from baseline (6, 21).
The percentage change in MI was different for both groups with the cerabur having lower value when comparing baseline to 1 month and higher values when comparing baseline to 3 months. This shows better initial clinical outcomes of the surgical stripping technique and superior stability of the cerabur results. However, the difference was not statistically significant.
These findings were analogous to the findings of Gholami et al., 2018 who found no difference between the recurrence rates of scalpel and ErCr: YSGG laser(21). However, they are in contrast with Penmetsa et al., 2019 who found significantly higher recurrence rates with scalpel depigmentation when compared to cryosurgery(22).
Gingival re-pigmentation after depigmentation is one of the drawbacks of the procedure. It is hypothesized that gingival re-pigmentation occurs due to the migration of neighboring melanocytes. The re-pigmentation rate of the two techniques was measured at the end of the follow-up period, 3 months post-operative, to compare the stability of the results(12, 23). DOPI and MI baseline values were the highest followed by 3 months, then 1 month. This is due to the re-appearance of some pigments in the form of spots, dots, or stria in some of the subjects at the 3 months assessment visit (24).
VAS was employed to evaluate the patients’ perception of pain in each arch due to its simplicity and reliability(25). There was no statistically significant difference between patient-reported VAS scores. These results were in contrast with Negi et al., 2019 who found significantly more pain in sites treated with cerabur compared to diode laser(6). The pain levels in this study were comparable to previous studies(23, 26) that reported more pain in sites treated with scalpel compared to laser and aligned with studies(12, 21) that didn’t find any significant difference in pain levels when comparing lasers with surgical scalpel. The frictional heat of the cerabur caused tissue coagulation and minimal bleeding. The localized heat causes coagulation, protein denaturation, drying, vaporization, and carbonization. As a result, blood vessels and sensory nerve endings are sealed. This may explain the faintly lower pain levels in the cerabur sites compared with the scalpel sites(6, 27).
GAIS was adopted from plastic surgery and cosmetic literature(28, 29) to measure the patient’s level of satisfaction with the aesthetic outcome. Cerabur had better patient satisfaction scores. More patients appreciated the less invasive and less bloody nature of the cerabur procedure over the scalpel surgery.