| Abstract|| |
Background: Mucocele is a common benign neoplasm of oral soft tissues and the most common after fibroma. It generally occurs in the lower lip and its treatment includes excision of cyst and the responsible salivary gland, in order to prevent recurrences.
Aims: To evaluate the capability of three different lasers in performing the excision of labial mucocele with two different techniques.
Materials and Methods: In the presented cases, excision was performed using two different techniques (circumferential incision technique and mucosal preservation technique) and three different laser wavelengths (Er,Cr:YSGG 2780 nm, diode 808 nm, and KTP 532 nm).
Results: All the tested lasers, regardless of wavelength, showed many advantages (bloodless surgical field, no postoperative pain, relative speed, and easy execution). The most useful surgical technique depends on clinical features of the lesion.
Conclusion: Tested lasers, with both techniques, are helpful in the management of labial mucocele.
Keywords: Circumferential incision technique, laser, mucocele, mucosal preservation technique
|How to cite this article:|
Romeo U, Palaia G, Tenore G, Vecchio AD, Nammour S. Excision of oral mucocele by different wavelength lasers. Indian J Dent Res 2013;24:211-5
Mucoceles are the most common of the benign soft tissue masses present in the oral cavity, after irritation fibroma. 
|How to cite this URL:|
Romeo U, Palaia G, Tenore G, Vecchio AD, Nammour S. Excision of oral mucocele by different wavelength lasers. Indian J Dent Res [serial online] 2013 [cited 2019 Nov 13];24:211-5. Available from: http://www.ijdr.in/text.asp?2013/24/2/211/116685
Mucoceles, by definition, are cavities filled with mucus. The mechanisms for mucus cavity development are extravasation or retention. Extravasation is the leakage of fluid from the ducts or acini of salivary glands in the surrounding tissues (mucus extravasation cyst), while the much less common retention phenomenon occurs as a result of a narrowed ductal opening due generally to inflammatory causes or salivary calculus that cannot adequately accommodate the exit of the produced saliva, leading to ductal dilation and surface swelling (mucus retention cyst). 
The extravasation mucocele, or extraductal mucus cyst, was described for the first time by Hamperl in 1932, with the name 'mucus granuloma' (Schleimgranulom).  It represents the most frequent swelling of the lower lip in the first two decades of life and has a peak occurrence between the second and third decade.  According to Jones and Franklin,  mucous extravasation phenomenon is the most frequently diagnosed salivary gland pathology in children, occurring mainly in the lower lip (77.9%), tongue (9.9%), and mouth floor (5.7%).
The retention mucocele, or sialocyst, is more rare than the first one. It occurs more commonly on the upper lip than the lower lip.  It is more frequent in adults, after the age of 40, with an incidence peak between the seventh and eighth decade of life. 
The two forms are clinically similar. Mucocele appears as a solitary circular painless swelling, fluctuant to palpation since the mucus content, painless, with diameter ranging from a few millimetres to a few centimetres,  and is of normal pink or bluish colour. When occurring on the lower lip, it affects mainly the canine area, the most susceptible to trauma.  It can also involve other minor salivary glands such as Blandin-Nuhn glands or the oral floor (ranulae). 
If surgical excision is not performed, particularly in the extravasation type, it is possible to observe a cyclical increase and decrease in size, as a result of the rupture of the cyst and subsequent new production of mucin.
The differential diagnosis should be placed with the fibroma, angioma, lipoma, and benign salivary gland neoplasm and others rare diseases such as acinic cell carcinoma. 
Histologically, in the extravasation form, the accumulation of saliva induces an acute foreign body reaction, with the recall, in the affected area, of macrophages and neutrophils; thereafter, these cells are replaced by granulation tissue of fibroblasts,  which defines a pseudocapsule. Due to the absence of a clear epithelial layer, extravasation mucocele may be considered a false cyst or pseudocyst.  By contrast, retention mucocele can be considered a true cyst, due to the presence of an epithelial layer of ductal origin, of cylindrical or flat cells. ,
The therapy, in both types of mucocele, is surgical and consists of excision of the cyst and the responsible minor salivary gland, to prevent any possible recurrence. ,
Two surgical procedures are described in its management, the Circumferential Incision Technique (CIT) in superficial localizations and the Mucosal Preservation Technique (MPT) in deep-seated lesions. ,
The aim of the study was to evaluate the capabilities of three different wavelengths in the surgical excision of oral extravasation mucocele through two different surgical techniques.
| Materials and Methods|| |
Three extravasation mucoceles were treated in the Department of Oral and Maxillofacial Sciences of Sapienza University of Rome.
Surgical treatments were performed by three different lasers: Erbium, Chromium-doped Yttrium Scandium Gallium Garnet (Er,Cr:YSGG), Potassium-Titanyl-Phosphate (KTP) and Diode laser.
Small and superficial lesions were treated by CIT, while in larger and deeper lesions, MPT was adopted.
A 14-year-old boy presented with fluctuant, painless, bluish swelling in the lower lip, about 0.5 cm in diameter [Figure 1]. A trauma preceded the onset of the mass. Story and appearance suggested the hypothesis of mucocele. It was decided to perform an excision by Er,Cr:YSGG laser 2780 nm (Waterlase® , Biolase, USA) by MPT.
|Figure 1: Incision by Er,Cr:YSGG laser of a lower lip mucocele of a young boy|
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After local anesthesia, a longitudinal laser incision was performed, at 2 Watt, 10% air, 10% water, 35 J/cm 2 , with a 600-μm fiber. The cyst was exposed [Figure 2] with a round-shaped instrument, and then the lesion was completely excised by laser at 1.5 Watt, 10% air, 10% water, 26 J/cm 2 [Figure 3]. A 4/0 resorbable suture was applied to protect a critical area often exposed to traumas.
|Figure 3: Surgical excision by laser at 1.5 Watt, 10% air, 10% water, 26 J/cm2|
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No complications occurred in the post-operative period; healing was excellent [Figure 4].
The histological examination confirmed clinical diagnosis.
A 13-year-old boy presented with pedunculate pink lesion of 0.5 cm in diameter, with multiple recurrences after traumas [Figure 5]. The patient also reported the habit of biting the lower lip.
Because of poor dimensions, the CIT by Diode laser 808 nm (Laser Innovation 30W ® , Italy) was adopted.
In local anesthesia, the lesion was clamped and excised circumferentially, with a 320-μm fiber at 2 Watt, T on =100 ms, T off =100 ms, 248 J/cm 2 [Figure 6]. No bleeding was observed and no suture was applied [Figure 7]. Healing was completed in three weeks [Figure 8].
|Figure 6: Surgical excision using a Diode laser 808 nm at 2 Watt, Ton=100 ms, Toff=100 ms, 248 J/cm2|
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Histology confirmed the clinical diagnosis of extravasation mucocele.
A 12-year-old boy presented with lower lip swelling, of 1 cm in diameter [Figure 9]. The lesion, covered by normal mucosa, was fluctuant, neither painful nor bleeding, and was noticed about 2 months ago. The size of the lesion suggested the MPT by KTP laser 532 nm (SmartLite® , DEKA, Italy).
In local anesthesia, a longitudinal incision was performed at 1.5 Watt, T on =100 ms, T off =100 ms, 212 J/cm 2 and with a 300-μm fiber [Figure 10]. Using a round-shaped instrument the lesion was exposed [Figure 11], and then excised at 1 Watt, T on =100 ms, T off =100 ms, 141 J/cm 2 [Figure 12]. A 4/0 resorbable suture was applied to protect the surgical wound.
|Figure 10: Linear incision using KTP laser 532 nm at 1.5 Watt, Ton=100 ms, Toff=100 ms, 212 J/cm2|
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|Figure 12: Surgical excision completed at 1 Watt, Ton=100 ms, Toff=100 ms, 141 J/cm2|
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The post-operative period was comfortable [Figure 13]. Histology confirmed clinical diagnosis.
| Results|| |
All the cases are successfully treated, without any recurrence. Er,Cr:YSGG 2780 nm, Diode 808 nm and KTP 532 nm showed good effectiveness when both techniques were adopted. Surgery was relatively quick and atraumatic, and no complications occurred in the intra- or postoperative period. The use of laser did not impede the histological diagnosis.
| Discussion|| |
Mucocele is a common oral pathology, especially in young patients. It is generally determined by a traumatic event that can cause the rupture of a excretory duct of salivary gland and it usually appears as a solitary painless swelling, fluctuant to palpation, in canine-bicuspid areas, with a normal pink or bluish colour, the latter depending from tissue cyanosis and vascular congestion associated with the stretched overlying tissue and the translucent character of the accumulated fluid beneath. 
After an appropriate differential diagnosis with other pathological forms (e.g., fibroma, lipoma, angioma, salivary neoplasms), surgical excision represents the only treatment for this disease. In fact, if surgical excision is not performed, particularly in the extravasation type, it is possible to observe a cyclical increase and decrease in the size of the lesion, as a result of the breakage of the cyst and new production of mucin.
Surgical excision must include the cyst, generally well-coated by a fibrous capsule, together with the minor salivary gland responsible for the mucocele, in order to avoid undesired recurrences.
Different surgical techniques have been described, depending generally on the lesion's clinical features. In traditional scalpel surgery, Baurmash  proposed complete excision for small lesions and unroofing procedure for large mucoceles.
Kopp and St-Hilaire proposed the MPT  surgical technique that consists of a linear incision of the mucosa on the top of the lesion, until it is identified; the lesion is then incised, decompressed and excised, together with the whole pathologic glandular tissue.
Vaporization by CO 2 laser was suggested by Huang et al.,  but this technique was questioned since it does not allow histological examination of the lesion.
Our recent studies , revealed that Erbium, KTP, and Diode lasers were ideal devices for oral soft tissues biopsy with poor thermal damage permitting a correct histological diagnosis. Er,Cr:YSGG is a solid-state laser with a wavelength of 2780 nm, with great affinity to water molecule. It has a fixed frequency of 20 Hz and also the possibility to perform air or water cooling. Its cutting hydrokinetic action allows working effectively on hydrated tissues without any thermal damage. Its physical characteristics make it effective on all tissues of the oral cavity, both hard (bone, tooth) and soft ones. This device, however, has no hemostatic capacity, so it must be used cautiously in vascular lesions (eg, angioma).
Diode laser 808 nm is a semiconductor device emitting an infrared radiation, with good affinity with oxidized hemoglobin and melanin. It may work in continuous or interrupted mode, through optical fibres of varied diameter. This is an excellent surgical laser for dentistry because it can cut all oral vascularised soft tissues. Moreover, by using such kind of laser, a bloodless surgical field can be easily obtained.
The KTP, also called Nd:YAG double frequency laser, is a solid state device, whose wavelength is obtained by halving the radiation produced by a Nd:YAG laser (1064 nm), by means of Potassium (K) Titanium (T) Phosphate (P) mirrors. The resulting radiation (wavelength, 532 nm) is green and has a higher affinity for oxidized hemoglobin if compared with all other dental lasers. For this reason, KTP laser can work using low power energy and influences, reducing thermal damages to target tissues. , Like diode laser, even more so, KTP laser can operate in bloodless field, with considerable advantages in the surgical management of many clinical diseases. KTP laser can work either in continuous or interrupted mode.
In this study, excision of the lesions was performed by these lasers adopting both CIT and MPT surgical techniques.
In the Erbium and KTP cases, due to the large size of lesions, MPT was chosen. This procedure prevents damages to deep anatomical structures of the lower lip, as the lower labial artery and superficial branches of mental nerve allows to see the responsible salivary gland at the base of the surgical site and its complete removal without loss of mucosal tissue. Tissue preservation is important in the lower lip since it is an aesthetic region. Only in the case treated by diode laser, CIT was preferred to remove the lesion, as it was small and pedunculate.
All tested devices showed advantages. In particular, KTP and diode lasers offered the best bleeding control and a high cutting activity, due to their higher affinity for hemoglobin, ,, whereas in the case of Er,Cr:YSGG, a precise and atraumatic cut was obtained, mainly in the first incision, according to other studies. , With all wavelengths, no scars or postoperative pain were observed, and histological diagnosis was made. No adverse side effects to laser surgery were emphasized in the presented cases.
In conclusion, laser surgery, regardless of wavelengths, can be considered helpful in oral mucocele management, offering technical and clinical advantages. However, it is important to choose the correct surgical technique according to the clinical features of the lesions.
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Department of Oral and Maxillofacial Sciences, "Sapienza" University of Rome, Rome
Source of Support: None, Conflict of Interest: None
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