laser-assisted new attachment procedure for the treatment of alveolar bone loss provoked by an aggressive pyogenic granuloma [version 3; peer review: 2 approved] Previously titled: Case Report: Interstitial-intralesional laser therapy and laser-assisted new attachment procedure for the treatment of an aggressive pyogenic granuloma

Background: A pyogenic granuloma (PG) is a common benign vascular lesion found in the oral cavity. The gold standard treatment of this lesion, comprising surgical excision and the elimination of etiological factors, cannot avoid tooth loss in the case of an aggressive pyogenic granuloma. Because of the prominent properties of 980 nm and 635 nm diode lasers in photocoagulation and photobiomodulation, we applied these wavelengths in the treatment of a large pyogenic granuloma with alveolar bone loss. Case presentation: Our objective was to use a combination of interstitial-intralesional laser therapy, photocoagulation and laserassisted new attachment procedure (LANAP) to preserve the teeth and periodontal tissue in a case of an aggressive pyogenic granuloma. Results: The patient was a 13-year-old Thai male with a pyogenic granuloma involving the interdental papilla and lingual gingiva of the lower left first and second molars. The teeth were also displaced by the lesion. After treatment with three sessions of photocoagulation, three sessions of interstitial-intralesional laser therapy and two sessions of LANAP, the lesion was completely resolved. The periodontal status of the teeth was improved at the six-month followup. Conclusion: The combination of interstitial-intralesional laser therapy, photocoagulation and LANAP was able to treat an aggressive Open Peer Review


Introduction
A pyogenic granuloma is a lobulated exophytic lesion with a painless red erythematous papule. This lesion presents either as a pedunculated mass or with a sessile base. Pathogenic factors include chronic low-grade local irritation, hormonal factors and certain medications. 1 As this lesion is composed of a vascular component, blade excision leads to considerable bleeding and demands hemostatic intervention.
Near-infrared and red diode lasers provide favorable photocoagulation and photobiomodulation. These diode lasers are able to stimulate the formation of blood clots and promote healing after surgery. 2 Therefore, these wavelengths are widely used for the treatment of vascular lesions in the oral cavity via surface photocoagulation and interstitial-intralesional laser therapy. 3 Regarding periodontal disease treatment, laser-assisted new attachment procedure (LANAP) is able to stimulate the formation of new attachments. This technique also has advantages in hemostasis, granulation tissue removal and the reduction of periodontal disease pathogens. 4 Hence, we introduce an interstitial-intralesional laser technique for the treatment of aggressive pyogenic granulomas, aiming to treat lesions with minor gingival excision and preservation of periodontal tissue. Periodontal tissue recovery was achieved by LANAP. This case report presents a typical pyogenic granuloma with aggressive characteristics treated through the use of interstitial-intralesional laser therapy, photocoagulation and LANAP.
Case report This case report was authorized by the ethics committee in human research, Khon Kaen University, reference number HE632040. The informed consent in Thai language from the patient and his parent was submitted to the ethics committee. The patient was a 13-year-old Thai male patient with a chief complaint of a rapidly swelling mass of the lower-left molar gingivae without pain for 10 days. There was no history of medical and psychological disorders of the patient and family. There was no systemic disease based on physical examination and laboratory investigation. The oral examination found an approximately 2Â2 cm erythematous pedunculated mass with ulceration in the area of the interdental papilla and on the lingual gingiva of tooth no. 36 and tooth no. 37. The mass was soft consistency with no bleeding and no pus

REVISED Amendments from Version 2
This version emphasizes the procedure of photo biomodulation in figure 5 besides explains the interesting result of initial blood clot observation.
Any further responses from the reviewers can be found at the end of the article ( Figure 1A). Tooth no. 37 exhibited buccal displacement, as shown in Figure 1B. Tooth no. 36 and tooth no. 37 exhibited second-degree and third-degree mobility, respectively.
The periapical radiograph showed distinct periapical and proximal bone destruction of tooth no. 36 and tooth no. 37 ( Figure 2).
A sample obtained with an incisional biopsy using a 980 nm diode laser at 4 W continuous-wave with a 320-micron optical fiber confirmed the diagnosis of a pyogenic granuloma with histopathological features presenting endothelial cell proliferation, fibroblasts, neutrophils and chronic inflammatory cells in the connective tissue stroma ( Figure 3A and B).
The lesion was firstly treated by interstitial-intralesional laser therapy under local anesthesia using a 980 nm diode laser at 3 W continuous-wave with a 200-micron optical fiber, as shown in Figure 4A and B. After the insertion of the optical fiber tangentially to the tooth and root surface into the lesion, the laser was irradiated for five seconds. The lesion became pale and harder, indicating that coagulation was achieved.
This treatment was then immediately followed by treatment with using a 635 nm diode laser via an 8 mm optical fiber at 100 mW, continuous wave and 4 J/cm 2 with non contact mode to the lesion at the buccal and lingual sites for 1 session per area to achieve photobiomodulation ( Figure 5). It was interesting that an initial blood clot was also observed over the lesion.  The patient was invited to have appointments for interstitial-intralesional laser therapy as previously described every two to three weeks. The remission of the pyogenic granuloma was observed, as shown in Figure 6A, B and C.
After two months of follow-up, the pyogenic granuloma involving soft tissue lesion was completely resolved. Tooth no. 37 returned to the normal position. The degrees of mobility of tooth no. 36 and tooth no. 37 were reduced to firstdegree and second-degree mobility, respectively. The periodontal pocket was approximately 4 to 6 mm. The patient was treated with LANAP under local anesthesia to preserve the teeth.     The LANAP procedure consisted of three steps 4 as follows: Step 1: After supragingival scaling with an ultrasonic scaler, a 980 nm diode laser at 0.7 W and continuous wave was delivered via a 200-micron optical fiber into the gingival sulcus ( Figure 7A). Then, it was followed by scaling and root planning ( Figure 7B).
Step 2: The epithelium and granulation tissue in the gingival sulcus was photoablated with a CW 980 nm diode laser at 2 W and continuous wave via a 200-micron optical fiber ( Figure 7C).
Step 3: Photodynamic therapy was administered using 0.1% toluidine blue as a photosensitizer and a 635 nm diode laser at 200 mW and CW for 15 sec via a 200-micron flexible optical fiber as a light source ( Figure 7D and E).
After one month of LANAP, tooth no. 37 showed only first-degree mobility. No recurrence of the pyogenic granuloma was observed. The periodontal pocket depth was reduced, and no gingival recession of tooth no. 36 and tooth no. 37 was observed. The periapical radiograph showed improvement through the indication of bone formation at the periapical areas of tooth no. 36 and tooth no. 37, as shown in Figure 8. The second LANAP was conducted to maintain the periodontal status. There was no adverse and unanticipated event in overall treatments and outcomes.
The chronology of the treatment regime for this patient as follows: 1. interstitial-intralesional laser therapy with photobiomodulation 2. repeating treatments of interstitial-intralesional laser therapy for 2 sessions every two to three weeks 3. the LANAP at a two-month after the third session of the interstitial-intralesional laser therapy and 4. repeating the final LANAP a month after the first LANAP.
Due to the limitation of travelling from the COVID-19 pandemic, the patient was followed up by the dentist at his local health services. We followed the patient for another two sessions every three months for a-6-month. There had been still no sign of recurrent of the lesion.
The patient and his parent were satisfied with the less invasion procedures and remission of the lesion with tooth preservation. Therefore, they allowed the authors as a team of surgeons to present and report this treatment for this may benefit the others who have the same condition.

Discussion
The selection of laser wavelengths for biopsy and therapy is an important choice. An infrared diode laser was chosen in this case because of its low absorption by water of soft tissue and its capacity to generate more heat producing a deeper coagulative zone. This resulted in ablation with hemostasis. 2 In this case, using a 635 nm diode laser at a power less than 0.5 W not only initiated clot formation but also resulted in photobiomodulation, which allowed a positive response to the healing process, such as an increase in microcirculation, the stimulation of cell growth, and a reduction in inflammatory substances. 5 The treatment of the pyogenic granuloma in this report preserved the teeth and surrounding periodontal tissue. This outcome was different from that of a previous report in which the treatment of a pyogenic granuloma at tooth no. 11 in an 11-year-old female patient by total excision of the lesion resulted in gingival defects. The patient had to undergo free connective tissue graft. 6 Our technique with combined laser therapy showed no gingival defect after the resolution of the lesion.
Regarding the LANAP used in this case report, it was based on the techniques of De Angelis et al. 4 which combined photoablation and photodynamic therapy. This differed from other LANAP techniques by using only either Nd;YAG laser 8 or diode laser 9 for ablating epithelium and granulation tissue in the gingival pocket and root resurface.
In addition, there was a case report with a similar lesion: an aggressive pyogenic granuloma near the area of tooth no. 46 and no. tooth no. 47 in an 11-year-old female patient. With the use of surgical excision, tooth no. 46 near the lesion had to be extracted. 7 While in our patient, who was treated by a combination of interstitial-intralesional laser therapy, photocoagulation and LANAP, we were able to preserve the teeth and eliminate the lesion.

Conclusions
From this report, a pyogenic granuloma with extensive periapical bone loss in a 13-year-old Thai male patient was treated with 980 nm and 635 nm interstitial-intralesional laser therapy, photocoagulation and LANAP. After six months of follow-up, there was no recurrence of the lesion and no complication of gingival recession. The periodontal status was improved. Therefore, we propose a combination of interstitial-intralesional laser therapy, photocoagulation and LANAP for the treatment of aggressive pyogenic granulomas to preserve the teeth involved in the lesions. It still one correction to do before indexing: Erase the words "and hemostasis" from the page 4, pargragrpah 5 th : The sentence becomes:

"This treatment was then immediately followed by treatment with using a 635 nm diode laser via an 8 mm optical fiber at 100 mW, continuous wave and 4 J/cm2 with non contact mode to the lesion at the buccal and lingual sites for 1 session per area to achieve photobiomodulation effects (Figure 5)."
Because the energy of the Photobiomodulation is not high enough to produce homeostasis effect (very low energy are not able to generate heat). There is a bio-modulation effects only.
There no need to reevaluate the manuscript again after this minor correction. The manuscript can be directly indexed.

Competing Interests: No competing interests were disclosed.
Reviewer Expertise: Oral surgery, laser dentistry

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.
Author Response 04 Oct 2022

Sajee Sattayut, Khon Kaen University, Khon Kaen, Thailand
We feel very grateful for your kind and keen suggestion. The modification was made as follows:-This treatment was then immediately followed by treatment with using a 635 nm diode laser via an 8 mm optical fiber at 100 mW, continuous wave and 4 J/cm 2 with non contact mode to the lesion at the buccal and lingual sites for 1 session per area to achieve photobiomodulation ( Figure 5). It was interesting that an initial blood clot was also observed over the irradiated area.
We just would like to report an interesting result on blood clot formation after photobiomodulation. Your suggestion is true. The dose which we used would not produce any photothermal effect.

Version 1
Reviewer Report 22 August 2022 https://doi.org/10.5256/f1000research.134716.r146327 © 2022 Namour S. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Samir Namour
Laser Application in Dental Medicine, Department of Dental Sciences, Faculty of Medicine, University of Liege, Liege, Belgium Very interesting paper. Authors treated with success the problem of severe bone resorption and tooth mobility that can result in teeth loss by preserving the proximal part of the tumor to avoid food retention and pocket complication in case of total excision of the proximal part at the tumor at the first step of surgery. This way offers a new and original way to treat this kind of risk. The paper is very interesting and an excellent and smart procedure to avoid future pocket complications and the loss of mobile teeth. Congratulations. To resume, this case report is bringing a new procedure and a new clinical management for the treatment of this kind of sensitive clinical cases. I highly recommend the indexing of this paper.
However, we advise authors to do some adaptations to the manuscript: Adaptation of the title to the content of the manuscript: 1.

Actually, the title is : Case Report: Interstitial-intralesional laser therapy and laserassisted new attachment procedure for the treatment of an aggressive pyogenic granuloma.
My proposition is to make it as follow: "Interstitial-intralesional laser therapy and laser-assisted new attachment procedure for the treatment of alveolar bone loss provoked by an aggressive pyogenic granuloma. Case Report".
In the case report description: Second paragraph: the sentence is: "The periapical radiograph showed distinct periapical bone destruction of tooth no. 36 and tooth no. 37" . We propose to add the words: and proximal in the sentence. The sentence becomes as follow: " The periapical radiograph showed distinct periapical and proximal bone destruction of tooth no. 36 and tooth no. 37 " ○ In the description of the photobiomodulation (PBM) paragraph: Authors have to add, despite the description in the photo 5 showing the way of application, a descriptive text mentioning: sites of application of PBM and the way of application, contact or non-contact, more details despite the photo. They have to also mention the total irradiation time per session, diameter of the fiber, etc.

○
In the same paragraph of PBM, authors have to erase the word "photocoagulation". Because the photobiomodulation can not deliver enough energy to heat tissue and to provoke any coagulate. It is a contradiction with the aim of the Photobiomodulation except if they omit to indicate the power used to induce a coagulation. The Diode (980 nm) can induce a coagulation under some irradiation conditions. The sentence becomes : " …continuous wave. and 4 J/cm2 to achieve photocoagulation and photobiomodulation effects ( Figure 5)". intralesional laser therapy, Photobiomodulation and LANAP were used in the treatment. Authors have to indicate clearly the chronology details. All of the 3 procedures were used in the same session or separately. We understand that Covid pandemic delayed some sessions, but authors should resume and indicate, in a separate paragraph the exact and advised chronology of 3 procedures per each session, the optimal timing for the different sessions and the chronology of the 3 procedures. Did they use the 3 procedures one after another in the same session or in separate sessions? What is the time between sessions? Their precise details and their news protocol has to allow other practitioners to perform similar procedures in order to obtain similar results.
In the discussion authors wrote : First paragraph: " An infrared diode laser was chosen in this case because of its hemoglobin absorption ability. This resulted in ablation with hemostasis". We advise authors to adapt their sentence similar to this way: " An infrared diode laser was chosen in this case because of its low absorption ability by water of soft tissue and its capacity to generate deeper and more heat. This resulted in ablation with hemostasis".
In fact, the diode laser ( 980 nm) has low absorption by hemoglobin. But because of its low absorption by water and by consequence this low absorption by water allows this wavelength to have a deeper penetration in tissue resulting in an important heat generation allowing coagulation.
○ Second paragraph, the sentence: "For the photocoagulation technique, in this case, using a 635 nm diode laser at a power less than 0.5 W not only promoted clot formation but also resulted in photobiomodulation, …" We advise authors to reformulate or to erase their paragraph because the Diode laser 635 nm (red light) at 0.1 W (energy delivered in the case report) cannot coagulate. This wavelength at 0.1 W can only induce a Photobiomodulation. To induce a coagulation, the delivered energy has to be used at high output power. We advise authors to erase the word: " photocoagulate" from their paragraph and replace it by "Photobiomodulation". Again, congratulations to the authors for this new and very interesting clinical procedure. They are bringing to the lecturer a new way to treat this kind of disease avoiding the loss of teeth.

Are enough details provided of any physical examination and diagnostic tests, treatment given and outcomes? Yes
Is sufficient discussion included of the importance of the findings and their relevance to future understanding of disease processes, diagnosis or treatment? Yes Is the case presented with sufficient detail to be useful for other practitioners?  Figure 5)".
Response: More details of laser irradiation and application were added as indicated in red.
It was noted that we applied this photobiomodulation to achieve hemostasis effect of the lesion. Therefore, the alteration was as below:-This treatment was then immediately followed by treatment with using a 635 nm diode laser via an 8 mm optical fiber at 100 mW, continuous wave and 4 J/cm 2 with non-contact mode to the lesion at the buccal and lingual sites for 1 session per area to achieve photocoagulation and photobiomodulation and hemostasis effects ( Figure 5).
First paragraph: " An infrared diode laser was chosen in this case because of its hemoglobin absorption ability. This resulted in ablation with hemostasis". We advise authors to adapt their sentence similar to this way: " An infrared diode laser was chosen in this case because of its low absorption ability by water of soft tissue and its capacity to generate deeper and more heat. This resulted in ablation with hemostasis".
In fact, the diode laser ( 980 nm) has low absorption by hemoglobin. But because of its low absorption by water and by consequence this low absorption by water allows this wavelength to have a deeper penetration in tissue resulting in an important heat generation allowing coagulation.
© 2022 Luk K. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Kenneth Luk
Faculty of Dentistry, The University of Hong Kong, Hong Kong, China In this case report, the treatment protocol with wavelengths were well thought out. Laser parameters and techniques were well documented. Patient management was comprehensive.
Pulsed Nd:YAG (1064nm) laser for LANAP protocol was cleared by the FDA in 2004. 1 Yukna demonstrated LANAP protocol with Nd:YAG laser can produce new cementum-mediated connective tissue attachment. 2 Recently, LANAP seem to be broadened to include near-infra-red diode wavelengths. 3 In this report, 980nm diode laser was used for LANAP protocol in step 1 and 2. Photodynamic therapy (PDT) with 635nm red laser was used in step 3. The initial LANAP protocol uses only Nd:YAG laser and no PDT was required. It would be more appropriate to describe the LANAP protocol in this case report as a modified LANAP protocol.
Alternative lasers for this case: Like 980nm, 810nm, 940nm and 970nm are also well absorbed by haemoglobin and melanin. They can also be used for ablation, coagulation and photobiomodulation.
Instead of PDT, photothermal therapy can be considered using Indocyanine green as a photosensitiser with 810nm diode laser.

Is the case presented with sufficient detail to be useful for other practitioners? Yes
LANAP techniques by using only either Nd;YAG laser 8 or diode laser 9 for ablating epithelium and granulation tissue in the gingival pocket and root resurface.
Owing to this being a case report, we would like to reserve other types of lasers or photosensitizers to be claimed that these would be applied as similar results have been proved in this study.