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A comparison of diode laser and Er:YAG lasers in the treatment of gingival melanin pigmentation
Vol. 113 No. 3 March 2012
ORIGINAL ARTICLE
A comparison of diode laser and Er:YAG lasers in the treatment of gingival melanin pigmentation Göksel S¸ims¸ek Kaya, DDS, PhD,a Günay Yapıcı Yavuz, DDS,b Muhammed A. Sümbüllü, DDS, PhD,c and Ertunç Dayı, DDS, PhD,d Erzurum, Turkey FACULTY OF DENTISTRY, ATATURK UNIVERSITY
Objectives. This study compared the use of diode and Er:YAG lasers in treating gingival melanin pigmentation (GMP) in terms of gingival depigmentation, local anesthesia requirements, postoperative pain/discomfort, depigmentation effectiveness, and total treatment duration. Study Design. Twenty patients (13 female, 7 male) referred with GMP were enrolled in the study. Patients were randomly divided into 2 groups. Group 1 was treated with a gallium aluminum arsenide diode laser with a continuous wavelength of 808 nm, and group 2 was treated with an Er:YAG laser with a continuous wavelength of 2,940 nm. Gingival depigmentation was performed by applying the laser at 1 W. Treatment was administered on a weekly basis until a normal pink gingival color was observable in clinical examination and photographs. In addition, patients were asked to evaluate the procedure by using a self-administered questionnaire. Results. Procedures were carried out without the need for any topical or local anesthetic, and no unpleasant events occurred during the actual procedure or the healing period. The total length of treatment was significantly shorter with the diode laser (group 1) than with the Er:YAG laser (group 2; P ⬍ .05). No melanin recurrence was detected during any follow-up session. Conclusions. Diode and Er:YAG lasers administered at 1 W both result in satisfactory depigmentation of GMP. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;113:293-299)
In addition to biologic and functional issues, the enhancement of soft-tissue esthetics has become a significant element in clinical dentistry.1,2 In line with today’s high cosmetic expectations, gingival pigmentation, particularly in the areas surrounding the labial aspect of anterior teeth, has become an important component of general esthetics.2,3 Gingival melanin pigmentation (GMP) has been well documented and may occur as a result of several physiologic and/or pathologic factors,4,5 the most common of which is the normal physiologic production of melanin,4 a nonhemoglobin-derived brown pigment produced by melanocytes and which is the most common endogenous pigment.6 Active melanocytes— dendritic cells independent of the surrounding epithelial cells that behave as unicellular exocrine glands— convert tyrosine to melanoprotein (melanin), which is transfered to keratinocytes by a
Assistant Professor, Department of Oral and Maxillofacial Surgery. Research Assistant, Department of Oral and Maxillofacial Surgery. c Assistant Professor, Department of Oral Diagnosis and Oral Radiology. d Professor, Department of Oral and Maxillofacial Surgery. Received for publication Feb. 23, 2010; returned for revision Mar. 1, 2011; accepted for publication Mar. 1, 2011. © 2012 Elsevier Inc. All rights reserved. 2212-4403/$ - see front matter doi:10.1016/j.tripleo.2011.03.005 b
way of melanosomes.1,2 Melanocytes and keratinocytes are located primarily in the basal and suprabasal cell layers of the epithelium. Gingival hyperpigmentation occurs when these cells deposit excessive amounts of melanin.1,2,5,6 This type of excessive pigmentation presents as a diffuse deep-purplish discoloration or brown and light-brown patches with irregular contours that do not alter the normal oral architecture.3,4,7 Although GMP does not represent a medical problem, because the most commonly affected intraoral tissue is the gingiva,6,7 GMP may result in complaints about poor esthetics,2,4,5,7,8 especially among individuals with excessive gingival display while smiling or talking.4,5 Hyperpigmentation may be observed in all races and at all ages, and it exhibits no gender predilection.5,7 Smoking has been reported to provoke excessive melanin production through the stimulation of melanocytes by polycyclic amines, such as nicotine and benzopyrenes, which are known to penetrate into the oral mucosa and bind to melanin. “Smoker’s melanosis,” first described by Hedin in 1977,9 is one type of benign local melanin pigmentation usually present in the attached gingiva of tobacco smokers. Within this general framework, gingival depigmentation has attracted considerable interest and led to the development of a range of treatments, including gingivectomy,10 gingivectomy with free gingival autografting,11 chemical treatment by agents, such as
293
ORAL AND MAXILLOFACIAL SURGERY 294 S¸ims¸ek Kaya et al.
90% phenol and 95% alcohol,12 electrosurgery,13 cryosurgery,2,5,7 abrasion with a diamond bur,14 and laser surgery.1,4,6,8 Laser surgery is considered to be one of the most effective, agreeable, and reliable techniques for treating GMP and has recently become the treatment of choice among clinicians.2,4,5 Diode and erbium:yttrium-aluminum-garnet (Er: YAG) lasers are relatively new additions to the surgical armory. Whereas the diode laser is used almost exclusively for soft-tissue surgery, Er:YAG lasers can be used for both hard- and soft-tissue surgery, and both lasers have been approved by the U.S. Food and Drug Administration for use in dentistry.15 However, the literature contains few case reports or comprehensive studies on gingival depigmentation using laser surgery. Therefore, the present clinical study was designed to compare the use of diode and Er:YAG lasers in treating GMP in terms of gingival depigmentation, local anesthesia requirements, postoperative pain/discomfort, depigmentation effectiveness, and total treatment duration.
MATERIAL AND METHODS Study design This randomized prospective study was designed to compare patient tolerance to and effectiveness of diode and Er:YAG lasers in the treatment of GMP. The study was conducted in line with the principles of the Helsinki Declaration of 1975, as revised in 2000, and ethical approval was obtained from the Ethics Committee of the Atatürk University Faculty of Dentistry. The purpose and procedures of the study were fully explained to all patients, and each patient signed a written informed consent form before participation. All surgical procedures were performed by the same 2 oral and maxillofacial surgeons, and all posttreatment observation was carried out by the same independent examiner unrelated to the study. Inclusion criteria Criteria for selection included: age ⱖ18 years; ability to understand verbal and written instructions; American Society of Anesthesiology physical status classification class I (normally healthy patient)16; and previously diagnosed, but untreated, bilateral melanin pigmentation in the anterior portion of the upper and lower gingiva evaluated as either moderate (deep brown or black) or severe (mixed in color) according to modified Dummet et al.17 criteria. Smokers who had gingival hyperpigmentation before taking up smoking were included among the study population. Exclusion criteria Exclusion criteria included: systemic diseases associated with pathologic gingival hyperpigmentation or im-
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proper wound healing (e.g., uncontrolled diabetes or autoimmune disease); pregnancy; regular use of medication; a history of postsurgical cheloids; and periodontal problems. Study population and clinical parameters The study population consisted of 20 adults (13 female, 7 male) ranging in age from 18 to 36 (mean age 25.65 ⫾ 0.9) who presented at the Department of Oral and Maxillofacial Surgery of the Atatürk University Faculty of Dentistry over a 24-month period from January 2009 to January 2011 with unattractive, diffuse, dark brown to black gingival discoloration in the labial aspect of the maxilla and mandible. A detailed medical history was taken that included pregnancy, breastfeeding, smoking habits, duration of pigmentation, systemic diseases associated and not associated with GMP, systemic symptoms of malignancy, and medications used. Skin pigmentation, perioral pigmented lesions, and lymph nodes as well as the shape, color, surface, and margins of GMP were assessed through detailed intraoral and extraoral examination. Patients were aware of the physiologic hyperpigmentation and understood that this phenomenon had no impact on their oral or systemic health. Of the 20 subjects, 1 was a nonsmoker, and the remaining 19 smoked ⬎10 cigarettes per day. Treatment groups Patients were randomly divided into 2 groups of 10 for treatment with either a diode laser (group 1) or an Er:YAG laser (group 2). Age distribution between the groups was homogeneous (group 1 25.7 ⫾ 1.6 years, group 2 25.6 ⫾ 1.9 years; P ⬎ .05). Group 1 consisted of 6 women and 4 men, and group 2 of 7 women and 3 men. Group 1. A gallium aluminum arsenide (GaAlAs) diode laser device (Doctor Smile erbium and diode laser; Lambda Scientifica, Vicenza, Italy) with a continuous wavelength of 808 nm was applied at 1 W of power via a pencil-sized handpiece containing a 300-m lasing fiber. The amount of power to be applied was determined based on the clinical experience of the operators. The procedure was performed in a contact mode and from a cervical-apical direction in all pigmented areas. A surgical aspirator was used to cool the operative site. Group 2. A gallium aluminum arsenide (GaA1As) Er:YAG laser device (Doctor Smile erbium and diode laser; Lambda Scientifica, Vicenza, Italy) with a continuous wavelength of 2,940 nm was applied at 1 W via a sapphire tip (1 mm diameter) in a fiber-optic handpiece. The amount of power to be applied was determined based on the clinical experience of the operators and the manufacturer’s recommendations. The proce-
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dure was performed with the handpiece at a distance of ⬃5 mm from the gingiva and using a diffused beam in a noncontact mode and from a cervical-apical direction in all pigmented areas. The operative site was cooled using air spray instead of water. Therapeutic procedure To determine patient tolerance to depigmentation, initial procedures were performed without the use of either topical or local anesthetics. Laser ablation began at the mucogingival junction, moving toward the free gingival margin, including the papillae, using an overlapping circular movement. Tissue was irradiated until the lased area demonstrated an opaque white or bullalike appearance, with care taken to avoid any carbonization and to ensure that the laser beam did not pass over teeth or mucosa. Adjacent teeth were protected from the laser beam by gently placing an anodized (blackened) periosteal elevator18 in the gingival sulcus. No periodontal dressing was required. During the 7-day postoperative period, patients were allowed up to 500 mg acetaminophen (Minoset; Roche, Istanbul, Turkey) per day as rescue medication, as required, and they were instructed to record how often the medication was used. Patients were also instructed to continue performing normal oral hygiene procedures. Laser treatment continued to be administered on a weekly basis, using the same settings, until the excess pigmentation was removed and a normal gingival pink color was achieved. Outcome assessment Each patient was asked to evaluate the treatment provided by using a self-administered modified version of Melzack’s McGill Pain Questionnaire19 and to include any remarks relevant to the treatment procedures. Patients were also asked to assess their degree of postsurgical discomfort by rating their recovery of oral functions (eating and speaking) using a 5-point Likert scale, with 1 representing “no trouble” and 5 representing “considerable trouble.” Evaluations were performed on postoperative days 1 and 7 (before the next laser ablation), and mean scores were obtained for each criterion for the overall treatment period. Pigmentation levels were evaluated by clinical examination and from digital photographs. Digital images of the area of gingival hyperpigmentation were obtained before and after treatment by using a digital camera (Finepix S20 Pro; Fuji Photo Film Co., Tokyo, Japan) mounted on a tripod, and all images were obtained by using the same magnification (⫻6 optical zoom) and focal distance (20 cm). In a further attempt at standardization, each patient’s head was positioned and stabilized by using a panoramic imaging unit (PM 2002 CC; Planmeca, Hel-
ORIGINAL ARTICLE S¸ims¸ek Kaya et al. 295
sinki, Finland) in accordance with routine orthopantomography procedures. Statistical analyses Statistical analysis was performed using SPSS, version 17.0 for Windows (SPSS, Chicago, IL, USA). KruskalWallis tests were used to assess local anesthesia requirements, postoperative pain/discomfort, and effectiveness of diode and Er:YAG in depigmentation, and t tests were used to identify differences in patient age and follow-up periods between groups, with a level of P ⬍ .05 considered to be statistically significant.
RESULTS Both diode and Er:YAG lasers showed excellent results in gingival depigmentation. After treatment, all patients had a normal gingival appearance, and no hemorrhaging, morphologic abnormalities, scarring, or infection in the irradiated area was observed at any time during the observation period. Patient acceptance of treatment was good in both groups, none of the patients required topical or local anesthesia during any of the laser ablation sessions, and none reported using postoperative painkillers. Mild pain was recorded in both groups (average pain scores: diode 1.5; Er:YAG 1.0) when consuming acidic, salty, or hot foods, particularly on the day of treatment, with no significant difference in the pain scores between groups. No other problems were reported by either group except for a burning smell during laser ablation in the diode group (P ⬍ .05; Table I). The total number of treatment sessions required varied according to the type of laser used. In group 2, it was higher than in group 1 (P ⬍ .05; Fig. 1; Table II). Average length of follow-up in group 1 was 14.30 ⫾ 1.96 months and in group 2 11.40 ⫾ 1.36 months, and no repigmentation was determined in any patient during follow-up (Figs. 2 and 3). Speech and eating scores on postoperative day 1 did not vary between the groups (P ⬎ .05; Fig. 4; Table II). On postoperative day 7 (before the next ablation session), eating and speaking scores were 1 in all patients. DISCUSSION Considerable advances in laser technology have been made since the advent of laser treatment of oral diseases,2 and today a great variety of laser systems are used in depigmentation, including CO2 (10,600 nm),6,9 diode (820 nm),20 neodymium-doped:YAG (1,064 nm)21 and Er:YAG (2,940 nm)22 lasers. Laser treatment is based on the conversion of light energy into heat through the process of photothermalysis.6 In the case of laser depigmentation, the ability of melanin-containing melanocytes to absorb the laser light is dependent on the wavelength of the
ORAL AND MAXILLOFACIAL SURGERY 296 S¸ims¸ek Kaya et al.
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Table I. Patient evaluation form Group 1 Question
R
Group 2 M
R
Key: 1 ⫽ not at all; 2 ⫽ mild; 3 ⫽ moderate; 4 ⫽ severe; 5 ⫽ very severe Was treatment painful? 10.50 1.0 10.50 Were you disturbed by a burning smell during treatment? 15.10 3.0 5.90 Did you experience pain on the day of treatment? 11.70 1.5 9.30 Did you experience pain during the week following treatment? 10.50 1.0 10.50 Did you experience itching during the week following treatment? 12.00 1.5 9.00 Did you notice a cosmetic change immediately after treatment? 11.65 1.5 9.35 Did you notice a cosmetic change during the week following treatment? 11.90 3.0 9.10 Did you notice a cosmetic change during the month following treatment? 11.50 5.0 9.5 Key: 1 ⫽ no; 2 ⫽ yes; 3 ⫽ over and above Did treatment meet your expectations? 12.50 3.0 8.50 Key: 1 ⫽ no; 2 ⫽ yes Would you repeat treatment if necessary? 10.50 2.0 10.50
M
P value
1.0 1.0 1.0 1.0 1.0 1.0 2.5 5.0
NS ⬍.05 NS NS NS NS NS NS
2.0
NS
2.0
NS
Group 1, diode laser; group 2, Er:YAG laser; R, rank; M, median.
Fig. 1. Graph showing the median scores of the total number of treatment sessions.
Table II. Postsurgical discomfort (eating and speaking scores) and number of treatment session
Speaking Eating Total no. of treatment sessions
Group 1
Group 2
R
M
R
M
P value
54.18 55.96 41.11
2.0 1.0 2.5
52.38 51.46 59.20
2.0 1.0 4.0
NS NS ⬍.05
Abbreviations as in Table I.
laser and its ability to penetrate tissue.8 Melanin has an absorption spectrum range between 351 and 1,064 nm.15,21,23 The diode lasers used in dentistry have a wavelength spectrum ranging from 800 to 980 nm, which allows high levels to be absorbed by soft tissue, water, and chromophores, such as melanin and oxyhemoglobin.23,24 In contrast, Er:YAG lasers produce invisible infrared light at a wavelength of 2,940 nm, which is ideal for absorption by hydroxy-
apatite and water,25 but which does not coincide with the absorption spectrum of melanin.26 Therefore, in cases of gingival hyperpigmentation, Er:YAG lasers are advantageous in limiting thermal damage but at a disadvantage regarding depigmentation. Because the Er:YAG wavelength corresponds to the absorption coefficient of water, laser irradiation transforms water within tissue into steam, producing thermomechanical “microexplosions.” The Er:YAG laser is able to remove excessive melanin by ablating tissue in the suprabasal and basal layers of the epithelium where melanocytes are found.4 In the present study, laser ablation of papillae gave excellent results in both groups. The shorter treatment time for full depigmentation in the diode group compared with the Er:YAG group may be attributed to the greater tissue penetration (1-10 mm) of diode lasers compared with Er:YAG lasers (1 m) and to the fact that the wavelength of diode lasers lies within the spectrum absorbed by melatonin, as discussed above. In both groups, the use of low-level laser power may have played a significant role in minimizing thermal damage to neighboring tissue and preventing complications, such as hypopigmentation, structural changes, gingival fenestrations, and bone exposure. Laser treatment of GMP has a number of advantages over other treatment modalities, including low intraand postoperative pain levels and rapid wound healing.4 Pain reduction after laser application may be attributed to the protein coagulum formed on the wound surface acting as a biologic dressing27 or to the laser’s ability to seal the ends of sensory nerves.28 Intra- or postoperative pain has been reported by some studies that used higher energy levels than those used in the present study,21,22 whereas other studies reported no intra- or postoperative pain.4 In our study, no intraoperative pain was reported; however, some patients re-
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ORIGINAL ARTICLE S¸ims¸ek Kaya et al. 297
Fig. 2. A, Clinical view of a 20-year-old woman with moderate gingival pigmentation before diode laser treatment. B, The gingiva maintained a normal clinical appearance with no incidence of repigmentation 18 months after completion of treatment.
Fig. 3. A, Initial view of 25-year-old woman with moderate gingival pigmentation before Er:YAG laser treatment. B, The clinical appearance of the gingiva exhibited a normal pink color 10 months after completion of treatment.
Fig. 4. A, Graph showing the median scores for eating. B, Graph showing the median scores of for speaking. Group 1, diode laser; Group 2, Er:YAG laser. Diagrams show minimum (0%), Q1 (25%), median (50%), Q3 (75%), and maximum as well as mean plus/minus standard error. Each circle represents a session.
ported mild pain while eating acidic, salty, or hot foods on the day of treatment (P ⬎ .05). The reported length of the healing period after depigmentation varies. Esen et al.1 reported that healing was complete within 2 weeks of depigmentation performed using a CO2 laser in superpulse mode at 10 W, Sharon et al.29 reported a healing period of 6 weeks after depigmentation using CO2 lasers in a continuous
mode at 3 W, and Atsawasuwan et al.21 reported that healing was complete between 1 and 3 weeks after depigmentation using an Nd:YAG laser at 6 W. Whereas laser ablation in those studies was performed in a single treatment session, in the present study, lasers were used at low levels of power to remove tissue gradually over a number of sessions. Although this technique has significant advantages in postoperative comfort, because
ORAL AND MAXILLOFACIAL SURGERY 298 S¸ims¸ek Kaya et al.
the small amounts of epithelial tissue removed in any single session do not require secondary gingival healing, the extended length of treatment time required to fully remove all melanin pigment represents a distinct disadvantage. This is especially true with an Er:YAG laser. Clinicians should be wary of the possibilities of repigmentation after gingival depigmentation. Time for repigmentation is variable. Esen et al.1 reported that a CO2 laser used in the superpulse mode resulted in repigmentation of 2 out of 10 cases over a follow-up period of 24 months, and Nakamura et al.8 reported repigmentation in 4 out of 7 cases over a period of 24 months after CO2 laser ablation, whereas other studies of laser ablation reported no repigmentation.4,6,21,22 Repigmentation occurs as a result of failure to remove all active melanocytes from the basal cell layer of the epithelium.4 The initiation of repigmentation has been attributed to the migration of melanocytes from the free gingiva.29 The close proximity of the adjacent teeth, which may be damaged by the laser beam, may make it impossible to remove all melanin at the gingival margins and interdental papillary regions, and incomplete vaporization of pigment in these sensitive areas tends to promote repigmentation.1 In this respect, diode lasers offer the exclusive advantage of safe application in direct contact or at extremely close proximity to tissue, thereby eliminating damage caused by “beam escape” in an open field.24 Thermal damage is similarly unlikely with Er:YAG lasers, which have the lowest tissue penetration of all laser types.4 Despite these positive characteristics of the lasers used in the present study, an anodized (blackened) periosteal elevator was used to protect neighboring teeth when applying the laser to the free gingival and interdental papillae to minimize the possibility of collateral damage. In addition, a handpiece with a small spot dimension was used for the same reason. In the present study, the results of gingival depigmentation were rated as satisfactory by both patients and the operator over a follow-up period ranging from 6 to 24 months, despite the fact that patients who smoked continued to do so over the course of laser treatment. However, it is likely that the improved esthetics achieved will not be sustainable over the long term if patients continue to smoke. The results of the present study show that both diode and Er:YAG lasers applied at 1 W can perform effective and satisfactory depigmentation of GMP and that both procedures are well tolerated by patients. On the other hand, the total treatment duration may not be optimal in either group, especially in the Er:YAG group. Further clinical studies are needed to establish
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the optimal treatment duration using the lowest amounts of laser power. The authors express special thanks to Dr. Armag˘an Hayırlı for his assistance with the statistical analysis. REFERENCES 1. Esen E, Haytac MC, Oz IA, Erdog˘an O, Karsli ED. Gingival melanin pigmentation and its treatment with the CO2 laser. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:522-7. 2. Arikan F, Gürkan A. Cryosurgical treatment of gingival melanin pigmentation with tetrafluoroethane. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;103:452-7. 3. Haresaku S, Hanioka T, Tsutsui A, Watanabe T. Association of lip pigmentation with smoking and gingival melanin pigmentation. Oral Dis 2007;13:71-6. 4. Azzeh MM. Treatment of gingival hyperpigmentation by erbium-doped:yttrium, aluminum, and garnet laser for esthetic purposes. J Periodontol 2007;78:177-84. 5. Prasad D, Sunil S, Mishra R, Sheshadri. Treatment of gingival pigmentation: a case series. Indian J Dent Res 2005;16:171-6. 6. Nakamura Y, Funato A, Wakabayashi H, Matsumoto K. A study on the removal of the melanin pigmentation of dog gingiva by CO2 laser irradiation. J Clin Laser Med Surg 1992;10:41-6. 7. Yeh CJ. Cryosurgical treatment of melanin-pigmented gingiva. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998; 86:660-3. 8. Nakamura Y, Hossain M, Hirayama K, Matsumoto K. A clinical study on the removal of gingival melanin pigmentation with the CO(2) laser. Lasers Surg Med 1999;25:140-7. 9. Hedin CA. Smokers’ melanosis. Occurrence and localization in the attached gingiva. Arch Dermatol 1977;113:1533-8. 10. Bergamaschi O, Kon S, Doine AI, Ruben MP. Melanin repigmentation after gingivectomy: a 5-year clinical and transmission electron microscopic study in humans. Int J Periodontics Restorative Dent 1993;13:85-92. 11. Tamizi M, Taheri M. Treatment of severe physiologic gingival pigmentation with free gingival autograft. Quintessence Int 1996;27:555-8. 12. Hasegawa A, Okagi H. Removing melagenous pigmentation using 90 percent phenol with 95 percent alcohol. Dent Outlook 1973;42:673-6. 13. Gnanasekhar JD, al-Duwairi YS. Electrosurgery in dentistry. Quintessence Int 1998;29:649-54. 14. Bishop K. Treatment of unsightly oral pigmentation. A case report. Dent Update 1994;21:236-7. 15. Aras MH, Göregen M, Güngörmüs¸ M, Akgül HM. Comparison of diode laser and Er:YAG lasers in the treatment of ankyloglossia. Photomed Laser Surg 2010;28:173-7. 16. American Society of Anesthesiologists. Physical status classification system. Available at: http://www.asahq.org/clinical/ physicalstatus. Accessed June 18, 2008. 17. Dummett CO, Barens G, Sakumura JS. Attitudes toward normal pigmentations of the oral tissues. Quintessence Int 1981; 10:1115-22. 18. Miserendino LJ, Pick RM, Blankenau RJ. Laser safety in dental practice. In: Miserendino LJ, Pick RM, editors. Lasers in dentistry. Chicago: Quintessence; 1995. p. 85-102. 19. Melzack R. The Mcgill Pain Questionnaire: major properties and scoring methods. Pain 1975;1:277-99. 20. Yousuf A, Hossain M, Nakamura Y, et al. Removal of gingival melanin pigmentation with the semiconductor diode laser: a case report. J Clin Laser Med Surg 2000;18:263-6. 21. Atsawasuwan P, Greethong K, Nimmanon V. Treatment of gin-
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gival hyperpigmentation for esthetic purposes by Nd:YAG laser: report of 4 cases. J Periodontol 2000;71:315-21. Tal H, Oegiesser D, Tal M. Gingival depigmentation by erbium: YAG laser: clinical observations and patient responses. J Periodontol 2003;74:1660-7. Genovese WJ, dos Santos MT, Faloppa F, de Souza-Merli LA. The use of surgical diode laser in oral hemangioma: a case report. Photomed Laser Surg 2010;28:147-51. Saetti R, Silvestrini M, Cutrone C, Narne S. Treatment of congenital subglottic hemangiomas: our experience compared with reports in the literature. Arch Otolaryngol Head Neck Surg 2008;134:848-51. Fujii T, Baehni PC, Kawai O, Kwawkomi T, Matsuda K, Kowashi Y. Scanning electron microscopic study of the Er:YAG laser on root cementum. J Periodontol 1998;69:1283-90. Anderson RR, Margolis RJ, Watenabe S, Flotte T, Hruza GJ, Dover JS, et al. Selective photothermolysis of cutaneous pigmentation by Q-switched Nd:YAG laser pulses at 1064, 532 and 355 nm. J Invest Dermatol 1989;93:28-32.
ORIGINAL ARTICLE S¸ims¸ek Kaya et al. 299 27. Fisher SE, Frame JW, Browne RM, Tranter RM. FrameJW, Browne RM, Tranter RMD. A comparative histological study of wound healing following CO2 laser and conventional surgical excision of canine buccal mucosa. Arch Oral Biol 1983;28: 287-91. 28. Schuller DE. Use of the laser in the oral cavity. Otolaryngol Clin North Am 1990;23:31-42. 29. Sharon E, Azaz B, Ulmansky M. Vaporization of melanin in oral tissues and skin with a carbon dioxide laser: a canine study. J Oral Maxillofac Surg 2000;58:1387-93.
Reprint requests: Dr. Göksel S¸ims¸ek Kaya Department of Oral and Maxillofacial Surgery Faculty of Dentistry Atatürk University 25240, Erzurum Turkey [email protected]
ORIGINAL ARTICLE
A comparison of diode laser and Er:YAG lasers in the treatment of gingival melanin pigmentation Göksel S¸ims¸ek Kaya, DDS, PhD,a Günay Yapıcı Yavuz, DDS,b Muhammed A. Sümbüllü, DDS, PhD,c and Ertunç Dayı, DDS, PhD,d Erzurum, Turkey FACULTY OF DENTISTRY, ATATURK UNIVERSITY
Objectives. This study compared the use of diode and Er:YAG lasers in treating gingival melanin pigmentation (GMP) in terms of gingival depigmentation, local anesthesia requirements, postoperative pain/discomfort, depigmentation effectiveness, and total treatment duration. Study Design. Twenty patients (13 female, 7 male) referred with GMP were enrolled in the study. Patients were randomly divided into 2 groups. Group 1 was treated with a gallium aluminum arsenide diode laser with a continuous wavelength of 808 nm, and group 2 was treated with an Er:YAG laser with a continuous wavelength of 2,940 nm. Gingival depigmentation was performed by applying the laser at 1 W. Treatment was administered on a weekly basis until a normal pink gingival color was observable in clinical examination and photographs. In addition, patients were asked to evaluate the procedure by using a self-administered questionnaire. Results. Procedures were carried out without the need for any topical or local anesthetic, and no unpleasant events occurred during the actual procedure or the healing period. The total length of treatment was significantly shorter with the diode laser (group 1) than with the Er:YAG laser (group 2; P ⬍ .05). No melanin recurrence was detected during any follow-up session. Conclusions. Diode and Er:YAG lasers administered at 1 W both result in satisfactory depigmentation of GMP. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;113:293-299)
In addition to biologic and functional issues, the enhancement of soft-tissue esthetics has become a significant element in clinical dentistry.1,2 In line with today’s high cosmetic expectations, gingival pigmentation, particularly in the areas surrounding the labial aspect of anterior teeth, has become an important component of general esthetics.2,3 Gingival melanin pigmentation (GMP) has been well documented and may occur as a result of several physiologic and/or pathologic factors,4,5 the most common of which is the normal physiologic production of melanin,4 a nonhemoglobin-derived brown pigment produced by melanocytes and which is the most common endogenous pigment.6 Active melanocytes— dendritic cells independent of the surrounding epithelial cells that behave as unicellular exocrine glands— convert tyrosine to melanoprotein (melanin), which is transfered to keratinocytes by a
Assistant Professor, Department of Oral and Maxillofacial Surgery. Research Assistant, Department of Oral and Maxillofacial Surgery. c Assistant Professor, Department of Oral Diagnosis and Oral Radiology. d Professor, Department of Oral and Maxillofacial Surgery. Received for publication Feb. 23, 2010; returned for revision Mar. 1, 2011; accepted for publication Mar. 1, 2011. © 2012 Elsevier Inc. All rights reserved. 2212-4403/$ - see front matter doi:10.1016/j.tripleo.2011.03.005 b
way of melanosomes.1,2 Melanocytes and keratinocytes are located primarily in the basal and suprabasal cell layers of the epithelium. Gingival hyperpigmentation occurs when these cells deposit excessive amounts of melanin.1,2,5,6 This type of excessive pigmentation presents as a diffuse deep-purplish discoloration or brown and light-brown patches with irregular contours that do not alter the normal oral architecture.3,4,7 Although GMP does not represent a medical problem, because the most commonly affected intraoral tissue is the gingiva,6,7 GMP may result in complaints about poor esthetics,2,4,5,7,8 especially among individuals with excessive gingival display while smiling or talking.4,5 Hyperpigmentation may be observed in all races and at all ages, and it exhibits no gender predilection.5,7 Smoking has been reported to provoke excessive melanin production through the stimulation of melanocytes by polycyclic amines, such as nicotine and benzopyrenes, which are known to penetrate into the oral mucosa and bind to melanin. “Smoker’s melanosis,” first described by Hedin in 1977,9 is one type of benign local melanin pigmentation usually present in the attached gingiva of tobacco smokers. Within this general framework, gingival depigmentation has attracted considerable interest and led to the development of a range of treatments, including gingivectomy,10 gingivectomy with free gingival autografting,11 chemical treatment by agents, such as
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90% phenol and 95% alcohol,12 electrosurgery,13 cryosurgery,2,5,7 abrasion with a diamond bur,14 and laser surgery.1,4,6,8 Laser surgery is considered to be one of the most effective, agreeable, and reliable techniques for treating GMP and has recently become the treatment of choice among clinicians.2,4,5 Diode and erbium:yttrium-aluminum-garnet (Er: YAG) lasers are relatively new additions to the surgical armory. Whereas the diode laser is used almost exclusively for soft-tissue surgery, Er:YAG lasers can be used for both hard- and soft-tissue surgery, and both lasers have been approved by the U.S. Food and Drug Administration for use in dentistry.15 However, the literature contains few case reports or comprehensive studies on gingival depigmentation using laser surgery. Therefore, the present clinical study was designed to compare the use of diode and Er:YAG lasers in treating GMP in terms of gingival depigmentation, local anesthesia requirements, postoperative pain/discomfort, depigmentation effectiveness, and total treatment duration.
MATERIAL AND METHODS Study design This randomized prospective study was designed to compare patient tolerance to and effectiveness of diode and Er:YAG lasers in the treatment of GMP. The study was conducted in line with the principles of the Helsinki Declaration of 1975, as revised in 2000, and ethical approval was obtained from the Ethics Committee of the Atatürk University Faculty of Dentistry. The purpose and procedures of the study were fully explained to all patients, and each patient signed a written informed consent form before participation. All surgical procedures were performed by the same 2 oral and maxillofacial surgeons, and all posttreatment observation was carried out by the same independent examiner unrelated to the study. Inclusion criteria Criteria for selection included: age ⱖ18 years; ability to understand verbal and written instructions; American Society of Anesthesiology physical status classification class I (normally healthy patient)16; and previously diagnosed, but untreated, bilateral melanin pigmentation in the anterior portion of the upper and lower gingiva evaluated as either moderate (deep brown or black) or severe (mixed in color) according to modified Dummet et al.17 criteria. Smokers who had gingival hyperpigmentation before taking up smoking were included among the study population. Exclusion criteria Exclusion criteria included: systemic diseases associated with pathologic gingival hyperpigmentation or im-
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proper wound healing (e.g., uncontrolled diabetes or autoimmune disease); pregnancy; regular use of medication; a history of postsurgical cheloids; and periodontal problems. Study population and clinical parameters The study population consisted of 20 adults (13 female, 7 male) ranging in age from 18 to 36 (mean age 25.65 ⫾ 0.9) who presented at the Department of Oral and Maxillofacial Surgery of the Atatürk University Faculty of Dentistry over a 24-month period from January 2009 to January 2011 with unattractive, diffuse, dark brown to black gingival discoloration in the labial aspect of the maxilla and mandible. A detailed medical history was taken that included pregnancy, breastfeeding, smoking habits, duration of pigmentation, systemic diseases associated and not associated with GMP, systemic symptoms of malignancy, and medications used. Skin pigmentation, perioral pigmented lesions, and lymph nodes as well as the shape, color, surface, and margins of GMP were assessed through detailed intraoral and extraoral examination. Patients were aware of the physiologic hyperpigmentation and understood that this phenomenon had no impact on their oral or systemic health. Of the 20 subjects, 1 was a nonsmoker, and the remaining 19 smoked ⬎10 cigarettes per day. Treatment groups Patients were randomly divided into 2 groups of 10 for treatment with either a diode laser (group 1) or an Er:YAG laser (group 2). Age distribution between the groups was homogeneous (group 1 25.7 ⫾ 1.6 years, group 2 25.6 ⫾ 1.9 years; P ⬎ .05). Group 1 consisted of 6 women and 4 men, and group 2 of 7 women and 3 men. Group 1. A gallium aluminum arsenide (GaAlAs) diode laser device (Doctor Smile erbium and diode laser; Lambda Scientifica, Vicenza, Italy) with a continuous wavelength of 808 nm was applied at 1 W of power via a pencil-sized handpiece containing a 300-m lasing fiber. The amount of power to be applied was determined based on the clinical experience of the operators. The procedure was performed in a contact mode and from a cervical-apical direction in all pigmented areas. A surgical aspirator was used to cool the operative site. Group 2. A gallium aluminum arsenide (GaA1As) Er:YAG laser device (Doctor Smile erbium and diode laser; Lambda Scientifica, Vicenza, Italy) with a continuous wavelength of 2,940 nm was applied at 1 W via a sapphire tip (1 mm diameter) in a fiber-optic handpiece. The amount of power to be applied was determined based on the clinical experience of the operators and the manufacturer’s recommendations. The proce-
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dure was performed with the handpiece at a distance of ⬃5 mm from the gingiva and using a diffused beam in a noncontact mode and from a cervical-apical direction in all pigmented areas. The operative site was cooled using air spray instead of water. Therapeutic procedure To determine patient tolerance to depigmentation, initial procedures were performed without the use of either topical or local anesthetics. Laser ablation began at the mucogingival junction, moving toward the free gingival margin, including the papillae, using an overlapping circular movement. Tissue was irradiated until the lased area demonstrated an opaque white or bullalike appearance, with care taken to avoid any carbonization and to ensure that the laser beam did not pass over teeth or mucosa. Adjacent teeth were protected from the laser beam by gently placing an anodized (blackened) periosteal elevator18 in the gingival sulcus. No periodontal dressing was required. During the 7-day postoperative period, patients were allowed up to 500 mg acetaminophen (Minoset; Roche, Istanbul, Turkey) per day as rescue medication, as required, and they were instructed to record how often the medication was used. Patients were also instructed to continue performing normal oral hygiene procedures. Laser treatment continued to be administered on a weekly basis, using the same settings, until the excess pigmentation was removed and a normal gingival pink color was achieved. Outcome assessment Each patient was asked to evaluate the treatment provided by using a self-administered modified version of Melzack’s McGill Pain Questionnaire19 and to include any remarks relevant to the treatment procedures. Patients were also asked to assess their degree of postsurgical discomfort by rating their recovery of oral functions (eating and speaking) using a 5-point Likert scale, with 1 representing “no trouble” and 5 representing “considerable trouble.” Evaluations were performed on postoperative days 1 and 7 (before the next laser ablation), and mean scores were obtained for each criterion for the overall treatment period. Pigmentation levels were evaluated by clinical examination and from digital photographs. Digital images of the area of gingival hyperpigmentation were obtained before and after treatment by using a digital camera (Finepix S20 Pro; Fuji Photo Film Co., Tokyo, Japan) mounted on a tripod, and all images were obtained by using the same magnification (⫻6 optical zoom) and focal distance (20 cm). In a further attempt at standardization, each patient’s head was positioned and stabilized by using a panoramic imaging unit (PM 2002 CC; Planmeca, Hel-
ORIGINAL ARTICLE S¸ims¸ek Kaya et al. 295
sinki, Finland) in accordance with routine orthopantomography procedures. Statistical analyses Statistical analysis was performed using SPSS, version 17.0 for Windows (SPSS, Chicago, IL, USA). KruskalWallis tests were used to assess local anesthesia requirements, postoperative pain/discomfort, and effectiveness of diode and Er:YAG in depigmentation, and t tests were used to identify differences in patient age and follow-up periods between groups, with a level of P ⬍ .05 considered to be statistically significant.
RESULTS Both diode and Er:YAG lasers showed excellent results in gingival depigmentation. After treatment, all patients had a normal gingival appearance, and no hemorrhaging, morphologic abnormalities, scarring, or infection in the irradiated area was observed at any time during the observation period. Patient acceptance of treatment was good in both groups, none of the patients required topical or local anesthesia during any of the laser ablation sessions, and none reported using postoperative painkillers. Mild pain was recorded in both groups (average pain scores: diode 1.5; Er:YAG 1.0) when consuming acidic, salty, or hot foods, particularly on the day of treatment, with no significant difference in the pain scores between groups. No other problems were reported by either group except for a burning smell during laser ablation in the diode group (P ⬍ .05; Table I). The total number of treatment sessions required varied according to the type of laser used. In group 2, it was higher than in group 1 (P ⬍ .05; Fig. 1; Table II). Average length of follow-up in group 1 was 14.30 ⫾ 1.96 months and in group 2 11.40 ⫾ 1.36 months, and no repigmentation was determined in any patient during follow-up (Figs. 2 and 3). Speech and eating scores on postoperative day 1 did not vary between the groups (P ⬎ .05; Fig. 4; Table II). On postoperative day 7 (before the next ablation session), eating and speaking scores were 1 in all patients. DISCUSSION Considerable advances in laser technology have been made since the advent of laser treatment of oral diseases,2 and today a great variety of laser systems are used in depigmentation, including CO2 (10,600 nm),6,9 diode (820 nm),20 neodymium-doped:YAG (1,064 nm)21 and Er:YAG (2,940 nm)22 lasers. Laser treatment is based on the conversion of light energy into heat through the process of photothermalysis.6 In the case of laser depigmentation, the ability of melanin-containing melanocytes to absorb the laser light is dependent on the wavelength of the
ORAL AND MAXILLOFACIAL SURGERY 296 S¸ims¸ek Kaya et al.
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Table I. Patient evaluation form Group 1 Question
R
Group 2 M
R
Key: 1 ⫽ not at all; 2 ⫽ mild; 3 ⫽ moderate; 4 ⫽ severe; 5 ⫽ very severe Was treatment painful? 10.50 1.0 10.50 Were you disturbed by a burning smell during treatment? 15.10 3.0 5.90 Did you experience pain on the day of treatment? 11.70 1.5 9.30 Did you experience pain during the week following treatment? 10.50 1.0 10.50 Did you experience itching during the week following treatment? 12.00 1.5 9.00 Did you notice a cosmetic change immediately after treatment? 11.65 1.5 9.35 Did you notice a cosmetic change during the week following treatment? 11.90 3.0 9.10 Did you notice a cosmetic change during the month following treatment? 11.50 5.0 9.5 Key: 1 ⫽ no; 2 ⫽ yes; 3 ⫽ over and above Did treatment meet your expectations? 12.50 3.0 8.50 Key: 1 ⫽ no; 2 ⫽ yes Would you repeat treatment if necessary? 10.50 2.0 10.50
M
P value
1.0 1.0 1.0 1.0 1.0 1.0 2.5 5.0
NS ⬍.05 NS NS NS NS NS NS
2.0
NS
2.0
NS
Group 1, diode laser; group 2, Er:YAG laser; R, rank; M, median.
Fig. 1. Graph showing the median scores of the total number of treatment sessions.
Table II. Postsurgical discomfort (eating and speaking scores) and number of treatment session
Speaking Eating Total no. of treatment sessions
Group 1
Group 2
R
M
R
M
P value
54.18 55.96 41.11
2.0 1.0 2.5
52.38 51.46 59.20
2.0 1.0 4.0
NS NS ⬍.05
Abbreviations as in Table I.
laser and its ability to penetrate tissue.8 Melanin has an absorption spectrum range between 351 and 1,064 nm.15,21,23 The diode lasers used in dentistry have a wavelength spectrum ranging from 800 to 980 nm, which allows high levels to be absorbed by soft tissue, water, and chromophores, such as melanin and oxyhemoglobin.23,24 In contrast, Er:YAG lasers produce invisible infrared light at a wavelength of 2,940 nm, which is ideal for absorption by hydroxy-
apatite and water,25 but which does not coincide with the absorption spectrum of melanin.26 Therefore, in cases of gingival hyperpigmentation, Er:YAG lasers are advantageous in limiting thermal damage but at a disadvantage regarding depigmentation. Because the Er:YAG wavelength corresponds to the absorption coefficient of water, laser irradiation transforms water within tissue into steam, producing thermomechanical “microexplosions.” The Er:YAG laser is able to remove excessive melanin by ablating tissue in the suprabasal and basal layers of the epithelium where melanocytes are found.4 In the present study, laser ablation of papillae gave excellent results in both groups. The shorter treatment time for full depigmentation in the diode group compared with the Er:YAG group may be attributed to the greater tissue penetration (1-10 mm) of diode lasers compared with Er:YAG lasers (1 m) and to the fact that the wavelength of diode lasers lies within the spectrum absorbed by melatonin, as discussed above. In both groups, the use of low-level laser power may have played a significant role in minimizing thermal damage to neighboring tissue and preventing complications, such as hypopigmentation, structural changes, gingival fenestrations, and bone exposure. Laser treatment of GMP has a number of advantages over other treatment modalities, including low intraand postoperative pain levels and rapid wound healing.4 Pain reduction after laser application may be attributed to the protein coagulum formed on the wound surface acting as a biologic dressing27 or to the laser’s ability to seal the ends of sensory nerves.28 Intra- or postoperative pain has been reported by some studies that used higher energy levels than those used in the present study,21,22 whereas other studies reported no intra- or postoperative pain.4 In our study, no intraoperative pain was reported; however, some patients re-
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ORIGINAL ARTICLE S¸ims¸ek Kaya et al. 297
Fig. 2. A, Clinical view of a 20-year-old woman with moderate gingival pigmentation before diode laser treatment. B, The gingiva maintained a normal clinical appearance with no incidence of repigmentation 18 months after completion of treatment.
Fig. 3. A, Initial view of 25-year-old woman with moderate gingival pigmentation before Er:YAG laser treatment. B, The clinical appearance of the gingiva exhibited a normal pink color 10 months after completion of treatment.
Fig. 4. A, Graph showing the median scores for eating. B, Graph showing the median scores of for speaking. Group 1, diode laser; Group 2, Er:YAG laser. Diagrams show minimum (0%), Q1 (25%), median (50%), Q3 (75%), and maximum as well as mean plus/minus standard error. Each circle represents a session.
ported mild pain while eating acidic, salty, or hot foods on the day of treatment (P ⬎ .05). The reported length of the healing period after depigmentation varies. Esen et al.1 reported that healing was complete within 2 weeks of depigmentation performed using a CO2 laser in superpulse mode at 10 W, Sharon et al.29 reported a healing period of 6 weeks after depigmentation using CO2 lasers in a continuous
mode at 3 W, and Atsawasuwan et al.21 reported that healing was complete between 1 and 3 weeks after depigmentation using an Nd:YAG laser at 6 W. Whereas laser ablation in those studies was performed in a single treatment session, in the present study, lasers were used at low levels of power to remove tissue gradually over a number of sessions. Although this technique has significant advantages in postoperative comfort, because
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the small amounts of epithelial tissue removed in any single session do not require secondary gingival healing, the extended length of treatment time required to fully remove all melanin pigment represents a distinct disadvantage. This is especially true with an Er:YAG laser. Clinicians should be wary of the possibilities of repigmentation after gingival depigmentation. Time for repigmentation is variable. Esen et al.1 reported that a CO2 laser used in the superpulse mode resulted in repigmentation of 2 out of 10 cases over a follow-up period of 24 months, and Nakamura et al.8 reported repigmentation in 4 out of 7 cases over a period of 24 months after CO2 laser ablation, whereas other studies of laser ablation reported no repigmentation.4,6,21,22 Repigmentation occurs as a result of failure to remove all active melanocytes from the basal cell layer of the epithelium.4 The initiation of repigmentation has been attributed to the migration of melanocytes from the free gingiva.29 The close proximity of the adjacent teeth, which may be damaged by the laser beam, may make it impossible to remove all melanin at the gingival margins and interdental papillary regions, and incomplete vaporization of pigment in these sensitive areas tends to promote repigmentation.1 In this respect, diode lasers offer the exclusive advantage of safe application in direct contact or at extremely close proximity to tissue, thereby eliminating damage caused by “beam escape” in an open field.24 Thermal damage is similarly unlikely with Er:YAG lasers, which have the lowest tissue penetration of all laser types.4 Despite these positive characteristics of the lasers used in the present study, an anodized (blackened) periosteal elevator was used to protect neighboring teeth when applying the laser to the free gingival and interdental papillae to minimize the possibility of collateral damage. In addition, a handpiece with a small spot dimension was used for the same reason. In the present study, the results of gingival depigmentation were rated as satisfactory by both patients and the operator over a follow-up period ranging from 6 to 24 months, despite the fact that patients who smoked continued to do so over the course of laser treatment. However, it is likely that the improved esthetics achieved will not be sustainable over the long term if patients continue to smoke. The results of the present study show that both diode and Er:YAG lasers applied at 1 W can perform effective and satisfactory depigmentation of GMP and that both procedures are well tolerated by patients. On the other hand, the total treatment duration may not be optimal in either group, especially in the Er:YAG group. Further clinical studies are needed to establish
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the optimal treatment duration using the lowest amounts of laser power. The authors express special thanks to Dr. Armag˘an Hayırlı for his assistance with the statistical analysis. REFERENCES 1. Esen E, Haytac MC, Oz IA, Erdog˘an O, Karsli ED. Gingival melanin pigmentation and its treatment with the CO2 laser. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:522-7. 2. Arikan F, Gürkan A. Cryosurgical treatment of gingival melanin pigmentation with tetrafluoroethane. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;103:452-7. 3. Haresaku S, Hanioka T, Tsutsui A, Watanabe T. Association of lip pigmentation with smoking and gingival melanin pigmentation. Oral Dis 2007;13:71-6. 4. Azzeh MM. Treatment of gingival hyperpigmentation by erbium-doped:yttrium, aluminum, and garnet laser for esthetic purposes. J Periodontol 2007;78:177-84. 5. Prasad D, Sunil S, Mishra R, Sheshadri. Treatment of gingival pigmentation: a case series. Indian J Dent Res 2005;16:171-6. 6. Nakamura Y, Funato A, Wakabayashi H, Matsumoto K. A study on the removal of the melanin pigmentation of dog gingiva by CO2 laser irradiation. J Clin Laser Med Surg 1992;10:41-6. 7. Yeh CJ. Cryosurgical treatment of melanin-pigmented gingiva. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998; 86:660-3. 8. Nakamura Y, Hossain M, Hirayama K, Matsumoto K. A clinical study on the removal of gingival melanin pigmentation with the CO(2) laser. Lasers Surg Med 1999;25:140-7. 9. Hedin CA. Smokers’ melanosis. Occurrence and localization in the attached gingiva. Arch Dermatol 1977;113:1533-8. 10. Bergamaschi O, Kon S, Doine AI, Ruben MP. Melanin repigmentation after gingivectomy: a 5-year clinical and transmission electron microscopic study in humans. Int J Periodontics Restorative Dent 1993;13:85-92. 11. Tamizi M, Taheri M. Treatment of severe physiologic gingival pigmentation with free gingival autograft. Quintessence Int 1996;27:555-8. 12. Hasegawa A, Okagi H. Removing melagenous pigmentation using 90 percent phenol with 95 percent alcohol. Dent Outlook 1973;42:673-6. 13. Gnanasekhar JD, al-Duwairi YS. Electrosurgery in dentistry. Quintessence Int 1998;29:649-54. 14. Bishop K. Treatment of unsightly oral pigmentation. A case report. Dent Update 1994;21:236-7. 15. Aras MH, Göregen M, Güngörmüs¸ M, Akgül HM. Comparison of diode laser and Er:YAG lasers in the treatment of ankyloglossia. Photomed Laser Surg 2010;28:173-7. 16. American Society of Anesthesiologists. Physical status classification system. Available at: http://www.asahq.org/clinical/ physicalstatus. Accessed June 18, 2008. 17. Dummett CO, Barens G, Sakumura JS. Attitudes toward normal pigmentations of the oral tissues. Quintessence Int 1981; 10:1115-22. 18. Miserendino LJ, Pick RM, Blankenau RJ. Laser safety in dental practice. In: Miserendino LJ, Pick RM, editors. Lasers in dentistry. Chicago: Quintessence; 1995. p. 85-102. 19. Melzack R. The Mcgill Pain Questionnaire: major properties and scoring methods. Pain 1975;1:277-99. 20. Yousuf A, Hossain M, Nakamura Y, et al. Removal of gingival melanin pigmentation with the semiconductor diode laser: a case report. J Clin Laser Med Surg 2000;18:263-6. 21. Atsawasuwan P, Greethong K, Nimmanon V. Treatment of gin-
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Reprint requests: Dr. Göksel S¸ims¸ek Kaya Department of Oral and Maxillofacial Surgery Faculty of Dentistry Atatürk University 25240, Erzurum Turkey [email protected]