ORIGINAL ARTICLES

A COMPARATIVE STUDY OF MAXILLARY LABIAL

FRENECTOMY PERFORMED WITH DIODE
AND ER,CR:YSGG LASERS
Velimira Georgieva, Elitsa Dzhongova, Izabella Petrova
Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine,
Medical University of Varna

ABSTRACT
INTRODUCTION: Frenectomy is one of the most common soft-tissue surgical procedures among children.
Short superior labial frenulum is a condition that may lead to a number of disorders in the permanent den-
tition arrangement and subsequent disturbing aesthetic results. The widespread laser application in pedi-
atric frenectomies is attributed to the fact that lasers claim to provide minimally invasive, short, blood-free
manipulation, significantly better patient’s perception, and possibility of treatment under local anesthesia.
AIM: The present paper aims to examine and compare the intraoperative parameters and the healing pro-
cess for the surgical treatment of short labial frenulum using Er:Cr:YSGG and diode lasers.
MATERIALS AND METHODS: The study included 52 patients aged 6 to 18 years; 28 of them underwent fre-
nectomy with an Er,Cr:YSGG laser (WaterLase, Biolase),while the remaining 24 patients were treated with a
diode laser (Elexxion).The object of the study involved signs such as bleeding ,duration of the procedure,need
of sutures, postoperative pain, discomfort during eating/speaking, wound healing, etc.
RESULTS: Our results showed that diode lasers provide better bleeding control during surgery, while
Er,Cr:YSGG lasers showed accelerated soft-tissue healing and reduced levels of pain in the early postopera-
tive period. Operative time, discomfort during eating or speaking, and the risk of recurrence showed no sta-
tistically significant differrence between the two lasers.
CONCLUSION: Laser-assisted frenectomy has many benefits for the patient as well as the oral surgeon.
Both diode and Er,Cr:YSGG lasers provide reduction of intraoperative bleeding, shortened surgical time,
uneventful postoperative period with low levels of pain, fewer eating/speech disorders, and adequate wound
healing.
Keywords: laser, frenectomy, oral surgery

INTRODUCTION
Address for correspondence:
Velimira Georgieva Frenectomy is one of the most common soft-tis-
Faculty of Dental Medicine sue surgical procedures among children. Short supe-
Medical University of Varna rior labial frenulum is a condition that may lead to a
84 Tzar Osvoboditel Blvd
number of disorders in the permanent dentition ar-
9002 Varna
e-mail: velimira.georgieva@abv.bg rangement and subsequent disturbing aesthetic re-
sults for a child’s psyche. Despite the minimal surgi-
Received: March 5, 2022 cal intervention in this type of procedure, it still re-
Accepted: April 18, 2022 quires the use of surgical instruments such as scal-

38 Scripta Scientifica Medicinae Dentalis, 2022;8(1):38-44

Medical University of Varna
 Velimira Georgieva, Elitsa Dzhongova, Izabella Petrova

pels, sutures, etc. This is the reason why, in most cas- tions, papillary or papillary penetrating type of fren-
es of early childhood frenectomy, patients are placed ulum causing diastema, a frenulum restricting upper
under general anesthesia. The widespread laser ap- lip movement and hindering hygienic habits in the
plication in pediatric frenectomies is attributed to anterior area of the maxilla. The study excluded pa-
the fact that lasers provide minimally invasive, short, tients who needed an increase of the upper lip length,
blood-free manipulation, significantly better pa- those who had unerupted permanent maxillary inci-
tient’s perception, and possibility of treatment under sors and those with general contraindications.
local anesthesia. The distance from the frenulum labial insertion
Most laser types can be applied in frenectomy: to its gingival/papillary insertion was measured in
diode lasers, Nd:YAG, CO2, Er:YAG, Er:Cr:YSGG, etc. mm with a graded periodontal probe (UNC-15) with
Diode lasers based on GaAlAs/GaAs semiconductor the aim to monitor any possible reinsertion at its ini-
bars, delivering wavelengths ranging from 810 to 980 tial attachment site.
nm, show a high degree of absorption of hemoglobin One laser system used in the study was Water-
and melanin, justifying their common use for soft- Lase MDX Er,Cr:YSGG (erbium, chronium: yttri-
tissue surgical manipulations. Their disadvantage, um, scandium, gallium, garnet) with a wavelength
however, is the significant thermal rise and char- of 2780 nm, operating frequency of 10–50 Hz, and
ring of tissues as well as the presence of smoke pro- power of 0.1 to 8.0 W. The laser has two pulse modes:
duced during soft-tissue ablation. By contrast, erbi- short pulses (H) 60µs and long pulses (S) 700µs. The
um lasers operate with water-air spray cooling and other laser used in the study was the diode Elexx-
thus prevent overheating and charring, eliminate un- ion, based on a GaAlAs semiconductor, with a wave-
pleasant burning sensations and do not create smoke. length of 810 nm, power of 1.5–50 W, and pulse fre-
Er:YAG wavelengths at 2940 nm and Er:Cr:YSGG at quency of up to 20000 Hz. The diode laser can be op-
2780 nm have a high absorption of water, collagen, erated in a continuous mode (CW) or a pulse mode
and hydroxyapatite. These wavelengths have a shal- with different pulse duration, depending on the type
low degree of penetration resulting in minimal dam- of manipulation.
age to surrounding tissues (1). The concurrent water- Contact anesthesia (lidocaine spray 10%) and
air spray, on the other hand, can limit the achieve- infiltrative anesthesia (Ubistesin 4%—about 0.5–0.7
ment of hemostasis. mL) were administered to all patients in both groups.
AIM The following parameters were registered intraop-
eratively: duration of surgery, need for sutures, and
The present paper aims to examine and com-
bleeding events (described as bloodless, punctate, or
pare the intraoperative parameters and the healing
profuse). After the manipulation, patients were asked
process for the surgical treatment of short labial fren-
to assess their perception and attitude by measuring
ulum using Er:Cr:YSGG and diode lasers.
their fear/anxiety level based on the Visual Analogue
MATERIALS AND METHODS Scale (VAS).
The study included 52 patients aged 6 to 18 In one of the cases of the Er,Cr:YSGG group
years; 28 of them underwent frenectomy with an (WaterLase, Biolase), we used an MDX 300
Er,Cr:YSGG laser (WaterLase, Biolase),while the re- handpiece and a sapphire cylindrical tip MT4 (6
maining 24 patients were treated with a diode la- mm length). The laser was set in soft-tissue cutting
ser (Elexxion). All patients were referred to the De- mode, in contact mode, power of 3.5 W, short-wave
partment of Oral Surgery or the University Medical pulse mode, frequency of 25 Hz, and water/air spray
and Dental Center at the Medical University of Var- cooling (10% water, 30% air) (Fig. 1). For the diode
na, Bulgaria, by an orthodontist or specialists from (Elexxion) excision of the frenulum, the laser was
other departments at the Faculty of Dental Medicine adjusted to pulse mode with a pulse frequency of 12
with the request to remove a short maxillary labial 000 Hz, pulse duration of 10 µs, and average power
frenulum. The following were set as inclusion crite- of 6 W (Fig. 2). The frenectomies in both groups were
ria for participation in the study: orthodontic indica- performed in a similar way. After stretching the lip,

Scripta Scientifica Medicinae Dentalis, 2022;8(1):38-44 39

Medical University of Varna
A Comparative Study of Maxillary Labial Frenectomy Performed with Diode and Er,Cr:YSGG Lasers

the tip was moved horizontally perpendicular to the

frenulum along the soft tissue surface, applying light
pressure and small brush-like strokes. First, we made
incisions in the superficial mucosa, then freed any
remaining fibrous adhesions and muscle insertions
in the periosteum until the release of the frenulum.
Afterwards, any leftover remnants of ablated tissue
were removed with sterile gauze soaked in hydrogen
peroxide. The wound surface was then dressed with
a Baneocin ointment (Fig. 3) (Fig. 4).

Fig. 3. Intraoral picture immediately after frenectomy per-

formed with an Er,Cr:YSGG (WaterLase).

Fig. 1. Intraoral picture during frenectomy performed

with an Er,Cr:YSGG (WaterLase).

Fig. 4. Intraoral picture immediately after frenectomy

performed with a diode laser (Elexxion). A significant
layer of charring can be noticed.

assess soft-tissue healing and the degree of epitheli-

alization of the operative wound (described as com-
plete, partial, or absent epithelialization).
Follow-up checks were scheduled on day 14 and
then 1.5 months after the manipulation to examine
Fig. 2. Intraoral picture during frenectomy performed any possible recurrence/relapse as well as any post-
with a diode laser (Elexxion). The suction is used in order
operative scarring.
to eliminate the fume produced by the ablation of tissues.
RESULTS
All patients were instructed to record their pain The total of 52 patients under study revealed
level on day 1, 3, 5, and 7 as well as any apparent the following types of labial frenulum attachment:
speech and/or eating disorders. A follow-up exami- 44.2% of them (n=23) exhibited a papillary type of
nation was scheduled on day 7 following surgery to maxillary labial frenulum, 36.5% (n=19) had a pap-

40 Scripta Scientifica Medicinae Dentalis, 2022;8(1):38-44

Medical University of Varna
 Velimira Georgieva, Elitsa Dzhongova, Izabella Petrova

illary penetrating type, and only 19.2% (n = 10) had lowing WaterLase-assisted manipulations: 7.1% of
a gingival type of frenulum. The frenulum type was the patients demonstrated partial epithelialization
determined according to Placek et al. classification and 92.9%—complete epithelialization. The diode
(1974): mucosal, gingival, papillary, and papillary laser group findings were as follows: 8.3% had no ep-
penetrating. ithelialization, 83.3%—partial epithelialization, and
Intraoperative bleeding was observed through- 8.3%—complete epithelialization (Fig. 5) (Fig. 6).
out the manipulation. There was complete absence
of bleeding in 86.5% of patients from both groups.
Punctate bleeding was reported in 13.5% from the
Er,Cr:YSGG laser group. It was observed in 7 patients
out of 28 in this group. Suturing was not necessary in
any of the 52 patients.
Patients’ fear/anxiety level was established fol-
lowing surgery by asking them to judge their percep-
tion and attitude from 0 to 10 according to the Visu-
al Analogue Scale (VAS). Children’s perception of the
manipulation proved to be very good: 84.6% of them
experienced no distress or minimal anxiety during
surgery, with average values of 1.4 on the scale. Dif-
ferences in perception with respect to the laser type
Fig. 5. Intraoral pictire on 7th postoperative day after fre-
were not detected. nectomy performed with an Er,Cr:YSGG (WaterLase)
Pain sensation was recorded on day 1 postoper- laser.
atively and revealed the following results: in the group
of patients treated with WaterLase (Er,Cr:YSGG)
21.4% of them experienced no pain, 50% had mild
pain, 21.4%—mild to moderate pain, 7.1% felt mod-
erate pain interfering with concentration. No pa-
tients reported severe pain. In the group of patients
treated with the diode laser, the respective pain sen-
sation values ​​were as follows: 8.3% felt no pain, 37.5%
experienced slight pain, 41.7% had mild to moderate
pain, 4.2%—moderate pain interfering with concen-
tration, and 8.3% reported severe pain. In the follow-
ups on day 3, 5, and 7, we registered slightly lower
pain levels in the WaterLase group, but there were no
statistically significant differences between the two
Fig. 6. Intraoral picture on 7th postoperative day after fre-
groups.
nectomy performed with a diode laser. Partial epitheliali-
Speech and/or eating disorders following sur- zation and fibrin layer can be noticed.
gery did not show any statistically significant differ-
ences between the Er,Cr:YSGG group and the diode
laser group. However, the WaterLase group revealed No recurrence was observed in any of the 52 pa-
slightly lower levels in this respect. tients in both groups during post-surgery examina-
tions on day 14 and 1.5 month later.
The observations of the degree of epithelial-
ization during wound healing on day 7 after sur- DISCUSSION
gery indicated significantly better epithelialization Bleeding control in laser-assisted manipula-
in patients from the WaterLase group (Er,Cr:YSGG). tions is a major advantage as it provides improved
There were no cases of absent epithelialization fol- visibility of the operative field and reduces surgi-

Scripta Scientifica Medicinae Dentalis, 2022;8(1):38-44 41

Medical University of Varna
A Comparative Study of Maxillary Labial Frenectomy Performed with Diode and Er,Cr:YSGG Lasers

cal time. The present study demonstrated a lack of disorders are among the most cited benefits of la-
or slight bleeding for both laser types, with diode la- ser-assisted treatments (16,17). In our study, as well
sers showing superiority in this regard (complete ab- as in other scholars’ research (6,10,12,18,19,20), low
sence of bleeding in 100% of cases). Similar results levels of postoperative pain and discomfort were
were obtained by Aras et al. (2), who compared diode registered,with prevalence of cases where no pain
laser versus erbium laser (Er:YAG) performance. The or mild pain was reported in the first days follow-
authors analyzed the levels of intraoperative bleed- ing surgery. Our records revealed that after day 5 no
ing induced by the Er:YAG laser and the CO2 laser, pain was experienced by over 90% of our patients.
reporting significantly reduced bleeding in patients Statistically significant differences concerning post-
treated with the latter (3,4,5). Likewise, the authors operative discomfort were established only on day
recognized that erbium lasers appeared to be inferior 1 after surgery, with lower levels of pain induced by
with regard to their hemostatic ability compared to the Er,Cr:YSGG laser. This can be explained with the
other laser types, attributing this to the pulsed mode production of less heat on tissues irradiated with the
of operation and the presence of water-air spray cool- Er,Cr:YSGG laser and the lack of charring, which is
ing. Better coagulation ability was observed with re- observed during diode laser-assisted manipulations.
duction of the water-air spray strength (2). Howev- A similar comparative study was carried out by Aras
er, it should be noted that bleeding with Er:YAG and et al. (2), who likewise did not find any significant
Er,Cr:YSGG lasers was minimal, no difficulties were differences in pain sensation and speech/eating dis-
encountered over the course of the procedure, visibil- orders postoperatively between applications of the
ity of the operative field was excellent, surgical time Er:YAG and the diode laser.
was shortened and there was no need for sutures. All Operative wound healing and faster epithelial-
these are factors commonly observed during manip- ization are the subject of research of many authors
ulation by conventional surgical methods (6,7,8). studying the healing processes following laser soft-
The reduction of operative time for laser frenec- tissue surgical manipulations. As reported also by
tomies, compared to standard surgical methods, can other researchers (3,5,9,21,22,23), the present study
be explained with the lower levels of intraoperative affirms improved epithelialization and a shortened
bleeding, improved visibility of the operative field as period of soft-tissue healing in the group treated with
well as the fact that the need for sutures is eliminated the Er,Cr:YSGG laser. Onur (24) compared the effica-
(3,6,7,9,10,11). Our study demonstrated very good re- cy of Er,Cr:YSGG versus diode lasers and shared sim-
sults regarding the shortened duration of all frenec- ilar findings of better wound healing results achieved
tomies performed, with a mean value of about 6 min- with Er,Cr:YSGG lasers. Some authors account for
utes, regardless of the type of laser. Pié-Sánchez et al. this fact with the lack of thermal damage to irradi-
(3) also reported an advantage of Er,Cr:YSGG over ated tissues and the relatively shallow penetration of
CO2 with regard to the duration of surgical time. erbium laser wavelength, which is attributed to the
Positive perception of the procedure and low- localization of their effects and minimal impact on
er levels of fear/anxiety are essential when operating adjacent tissues (1,4,22).
on pediatric patients so as to achieve better cooper- A number of authors explored the risk potential
ation, precision and performance under local anes- of recurrence after laser frenectomies (3,25,26,27).
thesia. This is supported by the fact that laser treat- The observations from our study did not show any
ment offers less intraoperative pain, reduces or elimi- recurrence after measuring the length of the frenu-
nates the need of infiltrative anesthesia, and shortens lum 6 weeks following surgery. Only minimal differ-
the duration of the procedure. A number of other au- ences were registered compared to the preoperative
thors studied the degree of positive perception of la- length, ranging to about 0.4 mm. Pié-Sánchez et al.
ser-assisted manipulations (12,13,14,15), all of which (3) and Olivi et al. (27) likewise reported no recur-
assessed it as very good. rence in 100% of patients under study, while Ozener
Improved quality of the postoperative peri- et al. (26) recorded relapse in 91.4% of cases.
od, reduction of pain perception, eating and speech
CONCLUSION

42 Scripta Scientifica Medicinae Dentalis, 2022;8(1):38-44

Medical University of Varna
 Velimira Georgieva, Elitsa Dzhongova, Izabella Petrova

Laser-assisted frenectomies have many benefits midline frenum and its treatment: a systematic
for the patient as well as the oral surgeon by offering review of the literature. Quintessence Int.
reduction of intraoperative bleeding, shortened sur- 2013;44(2):177-87. doi:10.3290/j.qi.a28925.
gical time, uneventful postoperative period with low 9. Amaral MB, de Ávila JM, Abreu MH, Mesquita
levels of pain, fewer eating/speech disorders, and bet- RA. Diode laser surgery versus scalpel surgery in
ter wound healing. Diode lasers provide better bleed- the treatment of fibrous hyperplasia: a randomized
ing control during surgery, while Er,Cr:YSGG lasers clinical trial. Int J Oral Maxillofac Surg.
show accelerated soft-tissue healing and reduced lev- 2015;44(11):1383-9. doi:10.1016/j.ijom.2015.05.015.
els of pain in the early postoperative period. 10. Kaur M, Sharma YPD, Singh P, Sharma S, Wahi
A. Comparative evaluation of efficacy and soft
REFERENCES tissue wound healing using diode laser (810 nm)
1. Grzech-Leśniak K, Matys J, Jurczyszyn K, versus conventional scalpel technique for second-
Ziółkowski P, Dominiak M, Brugnera Junior A Jr, stage implant surgery. J Indian Soc Periodontol.
et al. Histological and thermometric examination 2018;22(3):228-34. doi:10.4103/jisp.jisp_46_17
of soft tissue de-epithelialization using digitally 11. Eroglu CN, Tunç SK, Elasan S. Removal of epulis
controlled Er:YAG laser handpiece: an ex vivo fissuratum by Er,Cr:YSGG laser in comparison
study. Photomed Laser Surg. 2018 Jun;36(6):313-9. with the conventional method. Photomed Laser
doi: 10.1089/pho.2017.4413. Surg. 2015;33(11):533-9. doi:10.1089/pho.2014.3856.
2. Aras MH, Göregen M, Güngörmüş M, Akgül HM. 12. Calisir M, Ege B. Evaluation of patient perceptions
Comparison of diode laser and Er:YAG lasers in the after frenectomy operations: A comparison of
treatment of ankyloglossia. Photomed Laser Surg. neodymium-doped yttrium aluminum garnet laser
2010;28(2):173-7. doi:10.1089/pho.2009.2498. and conventional techniques in the same patients.
3. Pié-Sánchez J, España-Tost AJ, Arnabat- Niger J Clin Pract. 2018;21(8):1059-64. doi:10.4103/
Domínguez J, Gay-Escoda C. Comparative study of njcp.njcp_2_18.
upper lip frenectomy with the CO2 laser versus the 13. Hanna R, Parker S. The advantages of carbon
Er, Cr:YSGG laser. Med Oral Patol Oral Cir Bucal. dioxide laser applications in paediatric oral surgery.
2012;17(2):e228-32. doi:10.4317/medoral.17373. A prospective cohort study. Lasers Med Sci.
4. Kazakova RT, Tomov GT, Kissov CK, Vlahova 2016;31(8):1527-36. doi:10.1007/s10103-016-1978-8.
AP, Zlatev SC, Bachurska SY. Histological 14. Ugurlu F, Cavus O, Kaya A, Sener CB. Evaluation
gingival assessment after conventional and laser of dental anxiety in patients undergoing
gingivectomy. Folia Med (Plovdiv). 2018;60(4):610- dentoalveolar surgery with laser treatment.
6. doi:10.2478/folmed-2018-0028. Photomed Laser Surg. 2013;31(4):169-73. doi:
5. Suter VGA, Altermatt HJ, Bornstein MM. 10.1089/pho.2012.3364.
A randomized controlled clinical and 15. Viet DH, Ngoc VTN, Anh LQ, Son LH, Chu
histopathological trial comparing excisional DT, Ha PTT, et al. Reduced need of infiltration
biopsies of oral fibrous hyperplasias using CO2 and anesthesia accompanied with other positive
Er:YAG laser. Lasers Med Sci. 2017;32(3):573-81. outcomes in diode laser application for frenectomy
doi:10.1007/s10103-017-2151-8. in children. J Lasers Med Sci. 2019;10(2):92-96. doi:
6. Protásio ACR, Galvão EL, Falci SGM. laser 10.15171/jlms.2019.15.
techniques or scalpel incision for labial frenectomy: 16. Yadav RK, Verma UP, Sajjanhar I, Tiwari R.
a meta-analysis. J Maxillofac Oral Surg. Frenectomy with conventional scalpel and Nd:YAG
2019;18(4):490-9. doi:10.1007/s12663-019-01196-y. laser technique: A comparative evaluation. J Indian
7. Medeiros Júnior R, Gueiros LA, Silva IH, de Soc Periodontol. 2019;23(1):48-52. doi: 10.4103/jisp.
Albuquerque Carvalho A, Leão JC. Labial jisp_352_18.
frenectomy with Nd:YAG laser and conventional 17. Akpınar A, Toker H, Lektemur Alpan A, Çalışır
surgery: a comparative study. Lasers Med Sci. M. Postoperative discomfort after Nd:YAG laser
2015;30(2):851-6. doi:10.1007/s10103-013-1461-8. and conventional frenectomy: comparison of both
8. Delli K, Livas C, Sculean A, Katsaros C, Bornstein genders. Aust Dent J. 2016;61(1):71-5. doi: 10.1111/
MM. Facts and myths regarding the maxillary adj.12333.

Scripta Scientifica Medicinae Dentalis, 2022;8(1):38-44 43

Medical University of Varna
A Comparative Study of Maxillary Labial Frenectomy Performed with Diode and Er,Cr:YSGG Lasers

18. Ize-Iyamu IN, Saheeb BD, Edetanlen BE. 23. Sindel A, Dereci Ö, Hatipoğlu M, Özalp Ö, Dereci
Comparing the 810nm diode laser with ON, Kocabalkan B, et al. Evaluation of temperature
conventional surgery in orthodontic soft tissue rise following the application of diode and
procedures. Ghana Med J. 2013;47(3):107-11. ErCr:Ysgg lasers: an ex vivo study. Eur Oral Res.
19. Sezgin G, Öztürk Özener H, Meseli SE, Kuru L. 2018;52(3):131-6. doi:10.26650/eor.2018.479
Evaluation of patient’s perceptions, healing, and 24. Onur SG. Evaluation of pain perception and
reattachment after conventional and diode laser wound healing after laser-assisted frenectomy in
frenectomy: a three-arm randomized clinical pediatric patients: a retrospective comparative
trial. Photobiomodul Photomed Laser Surg. study. Photobiomodul Photomed Laser Surg.
2020;38(9):552-9. doi: 10.1089/photob.2019.4783. 2021;39(3):204-10. doi: 10.1089/photob.2020.4886.
20. Olivi G, Caprioglio C, Olivi M, Genovese MD. 25. Olivi G, Chaumanet G, Genovese MD, Beneduce C,
Paediatric laser dentistry. Part 4: Soft tissue laser Andreana S. Er,Cr:YSGG laser labial frenectomy: a
applications. Eur J Paediatr Dent. 2017;18(4):332-4. clinical retrospective evaluation of 156 consecutive
doi: 10.23804/ejpd.2017.18.04.12. cases. Gen Dent. 2010;58(3):e126-e133.
21. Soliman MM, Al Thomali Y, Al Shammrani A, 26. Öztürk Özener H, Meseli SE, Sezgin G, Kuru L.
El Gazaerly H. The use of soft tissue diode laser Clinical efficacy of conventional and diode laser-
in the treatment of oral hyper pigmentation. assisted frenectomy in patients with different
Int J Health Sci (Qassim). 2014;8(2):133-40. abnormal frenulum insertions: a retrospective
doi:10.12816/0006079 study. Photobiomodul Photomed Laser Surg.
22. Merigo E, Clini F, Fornaini C, Oppici A, Paties 2020;38(9):565-70. doi: 10.1089/photob.2020.4841.
C, Zangrandi A, et al. Laser-assisted surgery with 27. Olivi M, Genovese MD, Olivi G. Laser labial
different wavelengths: a preliminary ex vivo study frenectomy: a simplified and predictable technique.
on thermal increase and histological evaluation. Retrospective clinical study. Eur J Paediatr Dent.
Lasers Med Sci. 2013;28(2):497-504. doi:10.1007/ 2018;19(1):56-60. doi: 10.23804/ejpd.2018.19.01.10.
s10103-012-1081-8

44 Scripta Scientifica Medicinae Dentalis, 2022;8(1):38-44

Medical University of Varna