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Low-level laser therapy after molar extraction
Hana Kucerováa, Tatjana Dostálováa, Lucie Himmlováa,
Jirina Bártováa, Jirí Mazánekb
aInstitute of Dental Research - General Medical Hospital, Vinohradská
48, 120 60 Prague 2, Czech Republic,
E-Mail: dostalova@vus.cz
bFirst Medical Faculty of Charles University Prague, Czech Republic
ABSTRACT
The aim of the study was to evaluate the different frequencies of
low-level laser radiation (diode - 670 nm and Helium-Neon 632,8 nm)
on healing process after human molar extractions. Frequencies of 5
Hz, 292 Hz and 9000 Hz were used in experiments. Monitoring of secretory
IgA and albumin level in saliva and changes in bone density were used
as objective markers of biostimulatory effect. Subjective evaluation
of therapy was observed using scale (from - negative therapeutic effect;
++++ excellent treatment effect). Changes of sIgA, albumin levels
and bone density were compared in group of 150 patients (non-laser
therapy - 30 patients). Differences in levels of the saliva markers
(sIgA and albumin) were found to be significant comparing irradiated
and non-irradiated groups, as well as comparing groups irradiated
by various modulatory frequencies. It was observed significant differences
between increase of sIgA res. albumin and subjective treatment feelings.
Bone density after extraction and six-months after surgical treatment
was examined using the dental digital radiovisiography. There were
detected no significant differences between bone density in irradiated
and non-irradiated groups perhaps due to our used therapy diagram.
Keywords: dentistry, low-level laser radiation, secretory IgA,
albumin,
INTRODUCTION
Extractions of teeth are a part of the dentist's everyday work in his
office. It exists many reason for tooth extraction e.g. carries, periodontal
diseases, retention or semi-retention tooth etc. After extraction we
observe the wound and wound healing is one of the fundamental biological
processes allowing the preservation of organism after tissue damage
1,2. Regeneration takes place in three overlapping
phases 3.
- inflammatory phase: lasts several hours, the damaged tissue is infiltrated
with the leukocytes and makrophages infiltration and fibroblasts migration,
which also occurs and lasts from 1 to 3 days
- proliferation phase: between second and fourth day - neovascularisation,
type III collagen synthesis occurs between day 2 and 16.
- tissue reconstruction phase: in day 9 to 60 the type III collagen
is replaced with type I, the amount of blood vessels is reduced and
the reconstruction of fibrous tissue than continues for 6 to 12 months3.
After the extraction the open space of spongiosis is filled with blood
clot. The vein re-growth is followed by cells from healing bone marrow.
These cells are changed to osteoblasts. The bone is gradually strengthened
by lamellar bone. This primary spongiosis structure is, depending on
the local conditions, transformed into compact cortical orlamellar bone.
The formation of cortical layer, secondary spongiosis and marrow spaces
takes approximately 4 months. The final phase of bone differentiation
then takes place, where bone is re-modeled into Haversian systems and
secondary osteons appear. The re-modellation proceeds from the defect
bottom and edges into the central part of the wound. In the extraction
pocket the neovascularisation starts. The oxygen supply increases. The
oxygen is needed for collagen synthesis and wound epithelisation 4,5
. The components needed for collagen synthesis are provided by phagocytes
via damaged tissue. Consecutively, the collagen is transformed into
a specific form, the further cell dividing stops, and the veins created
by neovascularisation are reduced. The wound surface is epithelised,
and the tissue is healed 4.
A normal consequence of using elevators during extractions is that neighouring
teeth become sensitive and are difficult to chew with. From literature
is known that after extraction the alveolus is irradiated along with
the lingual and buccal bony wall 6. Faster coagulation,
less postoperative discomfort and quicker healing could be expected
7,8, 9. In our study we decided to objectively
evaluate the real effect of low-level laser radiation on healing process
after human lower molars extraction 1,3,5, 7,8,9,10.
The goal of study was to determine the effects of different frequencies
on the healing of extraction wounds via monitoring the changes in secretory
IgA and albumin levels in saliva before and after extraction and to
evaluate the effects of laser therapy on the healing process of the
bone wound via comparing the bone density of laser therapy-treated groups
of patients and a group who did not receive any laser therapy treatment
in comparison with subjective feeling of patients 1,3,8,9,10,11,12,13.
LASER EQUIPMENT
Low-level diode laser MED 100N (Lasotronic, Zug, Switzerland, diode
GaAlAs, wavelength 670 nm, power output 20 mW) and He-Ne Biostimul laser
(Medicom, Prague, Czech Republic, wavelength 632,8 nm, output 5 mW)
were used to laser therapy (Fig. 1). We used the following laser frequencies:
- diode laser MED 100N, frequency 292 Hz
- diode laser MED 100N, frequency 9000 Hz
- diode laser MED 100N, frequency 5 Hz
- He-Ne laser Biostimul, frequency 5 Hz
- control group - no laser radiation.
The use of low-level lasers is currently quite wide-spread in the dentistry
offices 2,13. These lasers are usually equipped
with not only the continuous beam but also with the adjustable frequency
setting. Often enough, they have pre-set Nogier frequencies, Mastalier-adjusted
for dentistry (A=292Hz, B=584Hz, C=1168Hz, D=2336Hz, E=4672Hz, F=9344Hz,
G=146Hz). The available knowledge in the field of biostimulatory laser
therapy do not give a clear-cut answer to the question what is better
for the organism: to use continuous beam, to switch among several different
frequencies, or to use a beam modulated into an exact frequency. Recommended
frequency levels for diagnoses in dentistry that can be found in the
literature either are modulated to a exact frequency or do not precise
the beam type used : E.g. for the healing of extraction wounds you can
find the following options:
- Smékal, Mašková: continuous (CW) beam, 5Hz
- Mastelier: 292Hz - "A" frequency per Nogier
- 3000-9000Hz per Navrátil
- 9300Hz per the guidebook for Oralaser Oralia Konstanz Switzerland
EXPERIMENTAL ARANGEMENT
We focused on monitoring.150 healthy patients between 18 and 65 years
old, after the extraction of their lower molars (reason for extraction:
semi-retention of third bottom molars, carries of teeth 48,47,46,36,37,38).
All patients, including the control group, were briefly informed about
the anti-inflammatory, analgesic, regeneratory, and immunomodulatory
effects of the laser before its use. In accordance with the 1964 and
1989 Helsinki Declaration they gave an informed agreement to cooperate
on this project. Patients were randomly divided into five groups. The
patients in every group were after extraction treated with low-level
diode laser or read light (group 5 - placebo effect)
- Group 1 (30 patients) - low-level diode laser MED 100N, (LASOTRONIC,
Zug, Switzerland), frequency, 292Hz, (diode GaAIAs, wavelength 670nm,
power output 20mW), density 1,5 J/ cm2
- Group 2 (30 patients) - low-level diode laser MED 100N, (LASOTRONIC,
Zug, Switzerland), frequency, 9000 Hz, (diode GaAIAs, wavelength 670nm,
power output 20mW), density 1,5 J/ cm2
- Group 3 (30 patients) - low-level diode laser MED 100N, (LASOTRONIC,
Zug, Switzerland), frequency 5Hz, (diode GaAIAs, wavelength 670nm,
power output 20mW), density 1,5 /J cm2
- Group 4 ( 30 patients) - He-Ne Biostimul laser (MEDICOM, Prague,
Czech Republic, wavelength 632,8nm, output 5mW), frequency 5Hz, density
1, 5 J/ cm2
- Group 5, control (30 patients), was not laser-treated at all following
the extraction.
OBJECTIVE AND SUBJECTIVE DETERMINATION OF TREATMENT EFFECT
Extraction procedure
We have applied local anesthesia (Supracain, Léciva, Czech Rep., Mepivastesin,
ESPE, BRD) and extracted the molar. We were used scissors and (or) elevators.
Immediately after the extraction, we have irradiated the patients in
the groups 1 - 4 with the respective lasers and respective frequencies
and energy density 1,5 J/cm2 1,9. The alveolus
was irradiated along with the lingual and buccal bony wall. We added
the dose into the central part of the wound. The patients were then
irradiated with laser for next 4 days.
Determining sIgA and albumin levels
An unstimulated saliva sample (approx. 1 - 1,5ml) was received from
each patient prior to the treatment and on the fifth day. Quantitative
determination of the secretory IgA and albumin was based on the principle
of radial diffusion of saliva sIgA or albumin from the circular pit
into a layer of agar gel containing monospecific antagonist. The resulting
circular precipitate was evaluated after 96 hours, when a final point
of immunodiffusion is achieved. The size of the ring is dependent on
the concentration of the proving protein, in our case sIgA and albumin.
The concentration of the sample is read directly from the reference
table in the kit. Usage of the commerce kit Binding Site allows fast
determination of sIgA and albumin in the saliva and guarantees reproducibility
and standardization of the method. The sIgA and albumin levels after
the treatment were referenced against the levels obtained from the first
saliva sample and expressed in percent using the test of Student at
the significance level P=0,05. The level of the first sample was considered
as 100% (Fig.2).
Bone Density
As an additional marker for analysis of laser biostimulatory effect
we evaluated the changes in bone density 6 months after extraction.
To obtain the X-ray image, we have used the dental digital radiography
method (Radio Visio Graph - RVG, Trophy, France). Isometric images were
captured to have possibility to compare the measurements via fixed-point
measurement method. We can measure up to 7 specific dimensions. The
method itself is non-invasive, since it takes only 15% of the radiation
exposure to obtain one conventional X-ray picture 14.
For evaluation we have used digital images taken immediately after the
extraction and consecutively after 6 months. To capture the integration
in the entire area of the extraction wound we have used the method of
sliced RVG images, which we have taken laterally through the extraction
wound 7. For that reason we have taken 3-5 slices, depending on the
extraction bone area. The slices were 2 mm apart. For each slice, we
have established density histogram, characterizing the density spread
across the slice. Histograms were evaluated using the computer software
program Sigma Scan and Sigma Scan Pro (Jandel, Germany) (Fig. 3).
Subjective patient's response to treatment
To evaluate less postoperative discomfort we prepared the special card
containing relevant information on the patients: personal and health
information, type of tooth and 5 degree scale of patient ´s sensation
from - no change to ++++ excellent results:
- no change
+ less postoperative disconfort
++ better subjective feeling
+++ best subjective feeling
++++ exellent result
RESULTS SIgA and albumin levels:
It was found the significant difference between patients irradiated
by laser and control group (Graf 1.) The levels of sIgA and albumin
increased in comparison to control. Comparison of the control group
with the laser therapy treated patients groups irradiated by various
frequencies (Graph 2) shows the most significant increase in the case
of patients treated with laser frequency 292 Hz, 9000 Hz and for both
the albumin levels and sIgA levels and for 5 Hz for sIgA level. Bone
density: The results are in graph form, which compiles the density levels
of individual slices for patients after extraction and after 6 months
as well as the difference between these two periods (Graph 3). The treatment
methods we have used (extraction wounds treated with 1,5 J/cm2 load
for 4 days following the extraction) have not shown any significant
differences in the bone density compared to the control group 12.
Subjective patient's response to treatment
The better patient ´s sensation after laser therapy was observed. The
patients felt more comfort after laser therapy for all types of laser
and different frequencies (Graph 4).
DISCUSSION AND CONCLUSION
The low-level laser has no influence on the process of osseintegration.
This effect was observed on fracture healing in rats using He-Ne laser
radiation 12. We have not found any differences
in the bone density compared to the control group. Frequencies recommended
for wound healing in literature often vary 1,8,9,10,.
Different frequencies can have varying effect on sIgA and albumin levels
8,9,15. It is therefore important to use frequencies
that increase both sIgA and albumin levels or at least don't have a
negative effect. We have found significant differences in sIgA and albumin
levels between patients exposed to radiation and those who were not.
The highest increase in sIgA and albumin levels were found in the group
treated with the frequency of 9000Hz. Increase in the level of markers
vs. the control group was found even in groups treated with other frequencies
(5Hz, 292Hz). Laser therapy objectively improves extraction wound healing
and can be recommended as a method of choice16,17.
We regard healing of extraction wounds with laser as contributory not
only due to subjective feelings of patients who accept laser therapy
largely positive due to its non-invasiveness and non-painfulness, but
also due to the objectively proven changes in sIgA and albumin levels
8,15.
ACKNOWLEDGEMENTS
This research has been supported by the Grant Agency Ministry of Health
of Czech Rep. No. 4091-3.
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Fig. 1. Low-level diode laser MED 100N (Lasotronic, Zug, Switzerland, diode GaAlAs,
wavelength 670 nm, power output 20 mW) and He-Ne Biostimul laser (Medicom,
Prague, Czech Republic, wavelength 632,8 nm, output 5 mW)
Fig. 2. Radial diffusion of saliva sIgA or albumin.
 
Fig. 3. Changes in bone density immediately
and 6 months after extraction.
Graph
1.: Secretory IgA and albumin after treatment in relation to their values
before treatment.
Graph
2.: Secretory IgA and albumin after treatment in relation to their values
before treatment.
Graph
3.: Bone density
Graph
4.: Subjective effect of laser irradiation
Editors note
To promote bone generation repeated irradiation is necessary. The alveolar
bone will be healed at 6 months post extraction with or without laser.
The interesting matter is the development during the early months and
the time when laser treated bone would be of the same quality as non-lased
bone at 6 months.
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