Large Submandibular Duct Sialolith Removal Using a Diode Laser: Description of the Technique Based on Two Cases and Narrative Review of the Literature

Abstract

Background/Objectives: The introduction of innovative technologies for the management of oral diseases has revolutionized treatment approaches, offering less invasive options and improved outcomes. Among oral cavity diseases, sialolithiasis is the most common disorder of the salivary glands. It involves the formation of calculi or stones within the salivary ducts, primarily affecting the submandibular gland due to its tortuous duct and the alkaline nature of its saliva. In particular, laser-assisted techniques have shown significant promise in enhancing the precision and safety in the management of sialolith removal. This article aims to present a case report and also explores the scientific evidence supporting these innovative methods, highlighting their benefits and limitations in clinical practice. Methods: This research was conducted using PubMed and Scopus search engines with a combination of relevant keywords, including laser, laser-assisted, laser treatment in combination with sialolith, sialolith removal, and sialoadenectomy. Selected articles were carefully reviewed to identify studies reporting data on the effectiveness of laser-assisted sialolith removal. Results: Results from the literature review indicate a growing interest in the application of diode laser and CO₂, with evidence suggesting improved clinical outcomes and reduced postoperative pain compared to traditional methods. Conclusions: Although lasers offer enhanced safety and reduced morbidity and bleeding, which ensures optimal visibility, certain limitations must be considered, including the need for an adequate training period. Further randomized clinical trials and longer follow-up studies are needed to better evaluate their use in sialolith removal.

1. Introduction

Sialolithiasis is a condition characterized by the development of one or more oval or round-shaped calcifications, known as sialoliths, occurring in the minor and major salivary glands. Calcifications might impact the glandular parenchyma or the associated ducts [1]. The pathogenesis of stones occurs due to the accumulation of organic debris in the duct lumen, associated with the deposition of calcium salts on the material. Both the organic and inorganic components originate from saliva [2]. Among the diseases affecting salivary glands, sialolithiasis has a rare occurrence and most commonly occurs in the submandibular gland, comprising 80% of cases, followed by the parotid gland (5–20%) and the sublingual and minor glands (1–2%) [3]. The tendency for sialolithiasis to develop in the submandibular gland is attributed to its mucous and alkaline secretion, as well as the antigravitational design of the pertinent excretory duct, which is both lengthy and has a tortuous path around the mylohyoid muscle [1,2]. About 40% of submandibular calculi are found in the distal portion of Wharton’s duct, while calculi in the parotid gland tend to be located within the glandular parenchyma [4]. Sialoliths may be asymptomatic or associated with painful swelling when their size obstructs the duct, with symptoms typically being exacerbating during meals. Chronic duct obstruction may, in fact, result in inflammation and infection. Typically ranging from 5 to 10 mm in size, sialoliths are referred to as megaliths or giant sialoliths when they exceed 15 mm, although this is a rare occurrence. The onset of symptoms is influenced by the dilation of the duct and the growth rate of the calculus, which is estimated to be between 1 and 1.5 mm per year. Besides radiographic examinations, specific imaging techniques such as computed tomography (CT), ultrasound, and contrast-enhanced sialography may be necessary for diagnostic purposes.

This is because non-palpable stones often yield false-negative results in radiography [2]. Additionally, sialendoscopy is also noteworthy as a diagnostic tool [5].

Once diagnostic confirmation is achieved, treatment may be performed. Patients with small sialolithiasis may benefit from conservative measures, including hydration, moist heat application, and gland massage. Sialendoscopy can also be employed; this minimally invasive technique allows for endoscopic visualization of the salivary ductal system. It serves as both a diagnostic and interventional tool for addressing inflammatory and obstructive conditions within the ductal system. Sialendoscopy has been shown to be an alternative to traditional surgery for stones measuring up to 4–5 mm in diameter, particularly when they are free within the duct lumen and mobile. Furthermore, the use of ultrasound for stone fragmentation has been found to enhance treatment outcomes. Despite significant technological advancements, 5–10% of patients with sialolithiasis are unable to be successfully treated using minimally invasive techniques [6]. Stones may be removed through surgical treatment conducted under local anesthesia and on an out-patient basis. However, for stones situated in the proximal part of the duct or within the submandibular gland, the preferred treatment is sialoadenectomy. This surgical procedure, however, is not without complications, which may include hypertrophic scar formation and potential injury to the surrounding anatomical structures [7]. To mitigate the morbidity associated with sialoadenectomy, a minimally invasive approach such as transoral sialolithotomy may be employed [8]. Over time, various types of lasers have been utilized in dentistry as alternatives to traditional surgery, including CO₂ laser, diode, and Nd:YAG laser. Among these, diode laser has emerged as the most advantageous due to its shallower penetration depth compared to Nd:YAG. Its higher absorption by hemoglobin, oxyhemoglobin, and melanin ensures greater safety for adjacent tissues [9]. Additionally, it exhibits excellent cutting and coagulation capabilities, making it a superior alternative to conventional soft tissue surgery [10,11]. Lasers offer several advantages, including enhanced coagulation properties, high-quality incisions, minimal bleeding, a low risk of nerve damage, and a reduced incidence of comorbidities [12,13].

This study aims to refer two cases of patients with a clinical diagnosis of sialolithiasis of the submandibular gland duct, treated with mini-invasive surgical excision performed using a diode laser and, also, to review the scientific evidence regarding the utilization of lasers in salivary gland surgery.

2. Materials and Methods

2.1. Case Report 1

A 60-year-old male patient was referred to our observation at the Complex Unit of Odontostomatology of the University of Bari ‘Aldo Moro’ complaining a 6-days history of fever, swelling, and pain localized to the left sublingual region.

At the intraoral examination, a consistent, mobile mass in the left sublingual region was observable, accompanied by edema of the submandibular duct and pus drainage (Figure 1A). In order to assess any radiological findings, the patient underwent OPT X-ray and mandibular occlusal radiography, which revealed a round radiopaque area located in the left inferior region of the mandible (Figure 1B,C).

A preliminary diagnosis of Wharton duct sialolithiasis was established. Surgical removal of the most superficial sialolith with successive salivary gland removal was decided due to the presence of a deeper sialolith; the patient provided informed consent and underwent surgical excision of the lesion performed with a diode laser. Local anesthetic in-filtration was administered in the sublingual region near the salivary calculus with an injection of 4% articaine combined with 1:100,000 epinephrine. A diode laser module, equipped with a 300 μm optical fiber emitting at a wavelength of 910 nm, with an output power of 2 W (Lasotronix, Piaseczno-Poland), was set in continuous wave mode. Intraoral access was achieved performing a linear incision along the path of Wharton’s duct, posterior to the sublingual caruncle (Figure 2A). Tissues were dissected using blunt forceps (Figure 2B). The absence of bleeding resulted in a more comfortable procedure for both the operator and the patient. The sialolith obstructing the submandibular duct was completely removed and measured approximately 18 mm in diameter (Figure 2C). No sutures were necessary, and the wound healed by secondary intention in the following 4 weeks. Submandibular manipulations were suggested during the healing period to promote saliva drainage. No intra- or post-operative complications were detected. Postoperatively, the patient assumed amoxicillin and clavulanic acid (875 mg + 125 mg) every 12 h for 6 days and did not experience edema or bruising, with no pain or discomfort. Follow-up evaluations on days 7 (Figure 2D) and 14 post-surgery (Figure 2E) revealed that the patient was asymptomatic.

At 21-days-follow-up, the patient reported pain and swelling of the submandibular region posterior to the previously treated area, where the spontaneous expulsion of the deep calculus was observable based on the intraoral examination (Figure 3A). The detected calculus was mechanically removed, and no suture was applied (Figure 3B,C). The patient underwent ultrasound to better define the presence of further sialoliths in the salivary gland. Regular follow-ups every 6 months were performed, and no pain or discomfort was evaluated.

2.2. Case Report 2

A 79 year-old female was referred to our attention at the Complex Unit of Odontostomatology ‘Aldo Moro’ University of Bari complaining of consistent swelling and pain localized to the left sublingual region. Her medical history was notable for hypertension and a documented allergy to amoxicillin. A clinical examination revealed a firm, well-defined submandibular mass measuring approximately 2 cm in diameter (Figure 4A). On intraoral inspection, a purulent exudate was observed draining from the floor of the mouth, suggestive of an active infectious process, likely of salivary gland origin. These findings warranted a further diagnostic evaluation to determine the underlying etiology and to guide appropriate management. A radiographic examination revealed a well-defined radiopaque area along the inferior border of the mandible, consistent with a clinical diagnosis of sialolithiasis (Figure 4B,C). Based on these findings, the patient underwent surgical excision of the salivary stone using a diode laser (continuous wave mode, 2.5 W), selected for its precision and minimal invasiveness, thereby reducing intraoperative bleeding and promoting optimal postoperative healing (Figure 4D–F).

During the postoperative course, the patient was treated with clarithromycin and monitored through follow-up visits at 7, 14, and 28 days. Progressive and uneventful healing was observed, with the complete resolution of symptoms and no postoperative complications, confirming both the efficacy of the surgical approach and the adequacy of antimicrobial management (Figure 5).

2.3. Literature Review

An extensive literature search was performed using the T databases to identify pertinent studies on the role and applications of lasers in the removal of sialoliths. Also, a manual review of the reference lists from all full-text articles and relevant reviews identified through the electronic search was undertaken. Further manual searches were conducted in the following journals: Journal of Oral and Maxillofacial Surgery, International Journal of Oral and Maxillofacial Surgery, Lasers in Medical Science, Journal of Clinical Laser Medicine & Surgery, Photomedicine and Laser Surgery, Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Journal of Laser Applications. The search utilized a combination of keywords and Medical Subject Headings (MeSH) terms, including the following: ((Laser [Mesh] OR (laser assisted) OR (laser treatment)) AND ((Sialolith [Mesh] OR (AI) OR (Sialolith Removal) OR (Sialadenectomy))). The inclusion criteria covered studies of any evidence level: randomized clinical trials, observational studies (cohort, case-control), case series, and case reports. Articles published in English from 1990 to 2024 were included. Clinical studies had to be based on human subjects diagnosed with salivary gland stones, explicitly excluding animal studies. The exclusion criteria eliminated review articles, letters to editors, and studies lacking full-text availability.

Two independent reviewers screened the titles and abstracts of the retrieved articles to identify potentially relevant studies. Full-text articles were subsequently evaluated for eligibility according to the defined inclusion criteria. From the selected articles, the authors extracted the following information: the names of the author(s), the publication year, and the study design. Also, the authors recorded the total number of patients treated, details on the laser type and settings, the site of the sialolith, complications during and after the procedure, follow-up details, and treatment outcomes. Obtained data were analyzed through both qualitative and quantitative methods. Overall, the study approach systematically located, evaluated, and compiled existing data on the role and applications of lasers in sialolith removal, providing valuable insights into the current state of the field and suggesting directions for future research.

3. Results

The search was completed in July 2024: 780 article titles were screened, and 40 abstracts were chosen for additional examination. Twenty articles were examined in their entirety to determine if they satisfied the inclusion requirements. Following additional review, 14 articles were eliminated for the following reasons:

• Full text not available (n = 10);
• Clinical study on animals (n = 4).

A total of eight full-text papers were included for data extraction after two more articles, which respected the inclusion criteria, were found through manual searching [14,15,16,17,18,19,20,21]. All collected data from the analysis of the selected articles were compiled into a table for a comprehensive examination (

Table 1. Clinical features and outcomes of included studies.

First Author (Year) Country	Study Design	N° Cases, Gender, Age	Sialolith Locations	Laser Type	Laser Setting	Pharmacological Therapy	Complications	Follow-Up	Outcome or Conclusions
Haas OL H. et al. (2018) [14]	Case series	2 cases, 1 M: 33 Y 1 F: 93 Y	Distal part of the submandibular duct and could be palpated intraorally	Diode laser	400 μm optical fiber emitting at a wavelength of 980 nm (infrared), 2.5 W output power, and in continuous pulse mode	Amoxicillin (500 mg) every 8 h for 7 days and oral acetaminophen (750 mg) every 6 h for 3 days	No intraoperative complications were reported	Evaluated on days 7, 14, and 30 free surgery.	The diode laser is a safe, minimally invasive option for this procedure, offering enhanced coagulation, high-quality incisions, no bleeding, low nerve damage risk, and minimal comorbidities.
Mathew J et al. (2022) [15]	Case report	1 case, 1 M: 50 Y	Behind the lower right second permanent molar	Diode laser	810 μm	-	Asymptomatic with undisturbed salivary flow	One year.	Newer treatment modalities offer effective alternatives to conventional surgical methods for sialoliths.
Kılınç et al. (2014) [16]	Case report	1 case, 1 F: 57 Y	In the anterior part of the left side of the floor in the mouth.	Diode laser	810 nm of wavelength, 4.0 W of power, 0.5 ms continuous wave and 1000 Hz of frequency was selected	Antibiotic: amoxicillin clavulonate 1000 mg, every 12 h for 5 d. Rovamycine every 12 h for 5 d. Anti-inflammatory: 100 mgr flurbiprofen every 12 h for 3 d	No sign of infection was observed, and salivary flow was normal	10th day.	An 810 nm diode laser is a safe and effective technique, offering excellent cutting and coagulation with a low complication rate, making it suitable for this surgical procedure.
Angiero et al. (2008) [17]	Case series	25 cases	Wharton’s duct	Diode laser	Wavelength of 810–830 nm, 2.5 W CW with 5–10 s irradiation time (energy density 12,5–25 J, flexible fiber 300–320 em	None of the patients required analgesic therapy	Postoperatively, three patients experienced odynophagia, impaired mouth opening, and submandibular swelling, which subsided in 2–3 days	For up to 6 years.	It is a valid alternative to traditional surgery.
Azaz et al. (1996) [18]	Case series	49 cases, 26 M, 23 W: (15 Y–18 Y)	Wharton’s duct: 47; Stensen’s duct: 2	CO2 laser	1020 8 W CW	Four patients had antibiotics for 5 days	Four patients experienced discomfort	7 days after for the follow-up. And after one year.	Excellent results with no bleeding, minimal scarring, and little discomfort. Sialadenectomy should be considered for patients who suffer from recurrent symptoms.
Barak et al. (1991) [19]	Case series	21 cases, 14 M, 7 W.	Wharton’s duct: 10 patients. Submandibular/sublingual glands: 8 patients. Stensen’s duct: 3 patients	CO2 laser	5 W/10 W in continuous mode	-	No complication	Three weeks.	Complete healing after three weeks.
Barak et al. (1993) [20]	Case series	6 cases, 2 M (22–54 Y) 4 W (19–32 Y)	Wharton’s duct: 4 patients. Submandibular gland: 2 patients	CO2 laser	10 W in continuous mode	-	No complication. Postoperative Swelling in 2 patients (Hilus of submandibular gland)	1 year.	Complete healing in 7 to 20 days.
Yang et al. (2011) [21]	Case series	19 cases, 12 M, 7 FW (8- 54 Y)	In the posterior half of Wharton’s duct	CO2 laser	4–6 W in continuous mode	-	One patient developed ranula formation after laser surgery	1–3.5 years.	The results suggest that transoral CO2 laser sialolithectomy is a simple, safe, and low-complication procedure suitable for outpatient treatment.

).

4. Discussion

Laser-assisted oral surgery represents an innovative frontier in modern dental practice. In recent years, the application of laser technology has paved new pathways for enhancing clinical outcomes in oral diseases. Given the current understanding of therapeutic approaches using lasers, this review aims to evaluate the existing knowledge and evidence on the use of a laser for salivary gland sialolithiasis. In dentistry, various devices are used, including diode lasers, Nd:YAG (Neodymium-Doped Yttrium Aluminum Garnet), Er:YAG (Erbium-Doped Yttrium Aluminum Garnet), Er,Cr:YAG (Erbium, Chromium: Yttrium Scandium Gallium Garnet), and CO₂ (Carbon Dioxide). In this review, it was observed that the devices described in the documented case reports and case series were the diode laser and the CO₂ laser.

From the four articles [18,19,20,21] describing clinical cases assisted by the CO₂ laser, a total of 87 patients underwent the surgical removal of sialoliths from salivary glands. These patients included 38 females and 49 males, with ages at diagnosis ranging from 8 to 85 years. According to the literature, calculi may arise in any salivary glands, although this condition mostly affects the submandibular glands from 80% to 92% and the parotid from 6% to 20% [22]. In fact, 76 calculi were located in the Wharton’s duct while only 5 were in the Stensen’s duct. The diagnosis of sialolithiasis is primarily clinical, based on patient-reported symptoms, palpation, and inspection. An accurate differential diagnosis is essential for establishing a proper treatment plan [23]. Stones located in the distal Wharton’s duct and the hilum might often be detected through bimanual palpation of the submandibular gland and the floor of the mouth. However, detecting parotid stones through palpation is significantly more challenging due to the complex anatomy of the duct system. Imaging plays a crucial role in the precise localization of sialoliths, while computed tomography (CT) and magnetic resonance imaging (MRI) are generally unnecessary for diagnosing sialolithiasis [24]. In all the reported cases, symptoms included oral pain and swelling. Radiological imaging was used to support the clinical diagnosis, specifically occlusal and panoramic radiographs in all cases. Only Yang et al. [21]. relied solely on palpation for diagnosing 12 patients, while for those presenting neck swelling and pain, a CT scan was performed. Surgical excision is required for a definitive diagnosis and treatment of this condition. Traditional surgery is considered more invasive due to the potential risk of damage to critical structures, such as the lingual nerve, facial nerve, marginal mandibular nerve, and hypoglossal nerve, as well as the risks of hemorrhage and hematoma and the likelihood of postoperative hypertrophic scarring at the surgical site [25]. All authors conclude that the use of lasers minimizes the invasiveness of treatments. They also emphasize that the technique is relatively straightforward, requiring only local anesthesia with minimal analgesia. This procedure may be performed on an outpatient basis through an intraoral approach. A major advantage is the minimal bleeding in the surgical field, which ensures optimal visibility [26,27].

The CO₂ laser achieves hemostasis, thereby reducing bleeding, shortening the duration of the intervention, and minimizing operative morbidity. All of these factors help reduce the patient’s emotional and physical stress, thereby promoting better recovery of the traumatized tissues [28,29]. Furthermore, it enhances patient comfort by eliminating the need for primary wound closure with sutures. The CO₂ laser has an absorption peak that closely matches that of water, making it especially effective for soft tissues with a high water content. In all cases, a continuous-wave CO₂ laser was used at power settings ranging from 5 W to 10 W. This approach ensured that the surrounding tissues were not damaged, as the thermal effects were confined to the treated area [30,31]. None of the 87 reported cases required sutures at the end of the procedure, thereby minimizing or eliminating the risk of postoperative sublingual ranula formation. This method supports effective salivary drainage without the need for marsupialization or drain placement. In the study by Yang et al. [21], only one case developed a ranula, while no complications were observed in the other patients during follow-up. All of the aforementioned features facilitate postoperative rehabilitation with minimal swelling, bleeding, infection, and pain, reducing the need for extensive medication. Traditionally, patients undergoing intraoral laser treatment require only analgesics and anti-inflammatory drugs following surgery. Therefore, in the study of Azaz et al. [18], 4 patients had antibiotics for 5 days, in which the surgical removal of the sialolith was challenging. A total of 29 patients who underwent the surgical removal of sialoliths from salivary glands using a diode laser have been reported in the four articles included in this review. These 29 patients comprised 12 females and 17 males, with ages at diagnosis ranging widely from 33 to 93 years. The authors of these four articles also agree that for the diagnostic suspicion of sialolithiasis, a clinical examination combined with imaging tests is essential. The observed signs in these patients included swelling in the gland area and the ability to detect the gland itself through bimanual palpation. To confirm the diagnosis, Angiero et al. [17] used CT scans for only some patients. In their study, stones could be palpated through superficial ductal localization in 15 patients, while in 10 patients, the stones were quite small. Additionally, in four patients, gland infection complicated palpation, necessitating further examination. Sialolithiasis pre-dominantly affects the submandibular gland, accounting for 80% of cases, followed by the parotid gland (5–20%) and the sublingual and minor glands (1–2%) In their case reports, Haas O.L. et al. [14] utilized both occlusal radiography and CBCT. Notably, the 93-year-old patient in his second case report—who was also the oldest patient identified in our study—had previously undergone surgery for sialolithiasis 15 years prior. In some cases, a radiographic examination alone provided sufficient information to proceed with surgery [15,16] Prior to surgery, local anesthetic infiltration was commonly administered. In the cases described by Kılınç et al. [16] and l as Haas OL et al. [14], a 4% articaine solution with 1/100,000 epinephrine was used to achieve local vasoconstriction. In contrast, Angiero decided on a topical anesthetic, specifically EMLA (lidocaine and prilocaine), rather than local anesthesia. During the procedure, an 810–830 nm diode laser was used in all examined cases. Notably, in the two cases described by Haas O.L. [14], the device was paired with a 400 µm optical fiber emitting a 980 nm (infrared) wavelength. The irradiation energy was 2.5 W for the 27 cases reported by Haas O.L. and Angiero [14,17], while a higher energy of 4 W was used in the case described by Kılınç et al. [16] Almost all of the procedures described were performed without the use of sutures, allowing secondary intention healing. The only exception was the case described by Kılınç et al. [16] where the duct was marsupialized in the floor of the mouth with Vicryl 5.0 sutures after the calculus was removed. For postoperative care, Kılınç, Y. [16] prescribed an antibiotic regimen consisting of amoxicillin–clavulanate every 12 h for 5 days and Rovamycin every 12 h for 5 days, along with a nonsteroidal anti-inflammatory drug (flurbiprofen 100 mg every 12 h for 3 days) and an oral rinse (chlorhexidine gluconate 0.2%, three times daily for 7 days). Haas O.L. [14] recommended oral amoxicillin (500 mg every 8 h for 7 days) and oral acetaminophen (750 mg every 6 h for 3 days). In contrast, Angiero et al. [17] did not deem analgesics necessary for his 25 patients, prescribing only rinses for hygiene purposes. Of the 29 patients, only 2 required repeated treatment, one due to incomplete removal of the stones and the other due to an inability to achieve duct patency. Thus, the treatment was considered unsuccessful in 2 out of 29 cases. The overall complication rate during the healing period was low. Only 3 patients experienced symptoms such as odynophagia, trismus, and submandibular swelling, which resolved within 2–3 days.

Importantly, in all the articles included in this review no cases of paresthesia were reported [8,9,10,11,12,13,14,15,16,17,18,19,20,21]. Paresthesias, which may affect the mandibular branch of the facial nerve, the hypoglossal nerve, or the lingual nerve, are among the most serious complications as-sociated with traditional surgery. This highlights the minimally invasive nature of laser technology [8,9,10,11,12,13,14,15,16,17,18,19,20,21,29,30,31,32], which reduces the side effects and operational risks, such as hypertrophic scarring, while providing superior coagulation for better visibility of the operative field [31,32]. Additionally, lasers minimize complications in patients with coagulation disorders. The study found positive outcomes with laser use in patients on anticoagulants, who did not need to discontinue their medication for the procedure, particularly in elderly patients and those with diabetes [32].

5. Conclusions

This study highlights the growing interest in modern medicine towards the utilization of new technologies that reduce the invasiveness of treatments. All authors of the articles included in this review emphasized that the use of diode and CO₂ lasers minimizes invasiveness in the surgical removal of sialoliths from salivary glands. All authors reported improved visibility of the surgical site, attributed to the absence of bleeding, compared to traditional surgery. Among the intraoperative advantages consistently reported were the reduced operative time and the avoidance of suturing the surgical site. Furthermore, all authors noted that postoperative edema was nearly absent, and patients experienced minimal pain. However, based on the collected data, it cannot be concluded that the use of diode and CO₂ lasers is associated with a reduction in postoperative antibiotic and/or analgesic therapies.

Despite the use of lasers being associated with enhanced safety and significantly reduced morbidity and all authors agreeing that this technique is an excellent alternative to traditional surgery, certain limitations must be considered, including the cost of the laser device and the need for an adequate training period.

Additionally, further randomized clinical trials and studies with longer follow-up periods are necessary to more accurately evaluate the use of lasers in salivary gland surgery.