The influence of continuous magnetic field on periodontal tissues under overdentures
Brković-Popović S, Stamenković D, Stanisić-Sinobad D, Rakocević Z, Zelić O.
[Article in Serbian]
INTRODUCTION: Last remained teeth with reduced alveolar support do
not have long-term prognosis, which is the reason for prolonging the
life and thus providing a stable support of overdenture. The data from
literature point out that static magnetic field has certain
possibilities in resolving such problems.
OBJECTIVE: Having in mind the pathogenetic factors which cause the
reduction of the alveolar ridge and periodontal problems in our
population, as well as osteoblastic and antiinflamatory activity, the
aim of this investigation was to assess the effect of static magnetic
field on periodontal tissue under the overdenture.
METHODS: The investigation involved 38 partially edentulous patients,
of both sexes and similar oral status who were bearers of a lower
complete overdenture and upper classic complete denture as antagonist
restoration. In the base of the lower overdenture the micromagnets were
installed in the region of the remained teeth, which had static
concentrated field of 60-80 mT power. The evaluation was done after 3, 6
and 12 months using the method of light densitometry. Periodontologic
analysis was performed by standard and modified periodontologic tests.
RESULTS: In patients with overdentures, after exposure to a magnetic
field, the density of bone was not significantly changed, but the use of
ANOVA disclosed changes in the observed interval. The tendency of
increased density of the alveolar part of the observed region was noted.
The region of the corresponding tooth of the contralateral side without
magnetic influence showed decreased density of this region in the
observed intervals. Plaque index and gingival index were improved under
the influence of the magnetic field, while after 6 and 12 months
following the magnet insertion statistically significant changes were
confirmed. The magnetic devices did not show any influence on the level
of the gingival margin and junction epithelium.
CONCLUSION: Static magnetic field is to be considered as a
noninvasive procedure which is recommended to patients with reduced
number of teeth and alveolar support.
Brković-Popović S, Stamenković D, Stanisić-Sinobad D, Rakocević Z,
Zelić O (July 2009). "[The influence of continuous magnetic field on
periodontal tissues under overdentures.]" Srpski arhiv za celokupno lekarstvo. 137(7-8):363-70. PMID: 19764589
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The role of magnets in the management of unerupted teeth in children and adolescents.
Cole BO, Shaw AJ, Hobson RS, Nunn JH, Welbury RR, Meechan JG, Jepson NJ.
Department of Child Dental Health, Department of Oral Surgery, and
Department of Restorative Dentistry, Dental School & Hospital,
Richardson Road, Newcastle upon Tyne, UK.
This case report describes the use of magnets in the management of
teeth that fail to erupt. Eight children aged between 10 and 15 years
were treated. Magnetic traction was applied to two premolars and six
molars. Seven teeth (one premolar and six molars) erupted successfully
(mean treatment time with magnetic traction: 7.5 months). One premolar
failed to erupt; serial radiographic assessment over a 9-month period
revealed no evidence of movement and so the magnetic fixture was
removed. Histological evaluation of tissue samples taken from around the
fixture revealed no evidence of abnormal pathology.
Int J Paediatr Dent 2003 May;13(3):204-7
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Pulsed electromagnetic fields promote bone formation around dental implants inserted into the femur of rabbits.
Matsumoto H, Ochi M, Abiko Y, Hirose Y, Kaku T, Sakaguchi K.
Department of Fixed Prosthodontics, School of Dentistry, Health
Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293
The present study examined the effect of applying a pulsed
electromagnetic field (PEMF) on bone formation around a rough-surfaced
dental implant. A dental implant was inserted into the femur of Japanese
white rabbits bilaterally. A PEMF with a pulse width of 25 microseconds
and a pulse frequency of 100 Hz was applied. PEMF stimulation was
applied for 4 h or 8 h per day, at a magnetic intensity of 0.2 mT, 0.3
mT or 0.8 mT. The animals were sacrificed 1, 2 or 4 weeks after
implantation. After staining the resin sections with 2% basic fuchsin
and 0.1% methylene blue, newly formed bone around the implant on tissue
sections was evaluated by computer image analysis. The bone contact
ratios of the PEMF-treated femurs were significantly larger than those
of the control groups. Both the bone contact ratio and bone area ratio
of the 0.2 mT- and 0.3 mT-treated femurs were significantly larger than
the respective value of the 0.8 mT-treated femurs (P < 0.001). No
significant difference in bone contact ratio or bone area ratio was
observed whether PEMF was applied for 4 h/day or 8 h/day. Although a
significantly greater amount of bone had formed around the implant of
the 2-week treated femurs than the 1-week treated femurs, no significant
difference was observed between the 2-week and 4-week treated femurs.
These results suggest that PEMF stimulation may be useful for promoting
bone formation around rough-surfaced dental implants. It is important to
select the proper magnetic intensity, duration per day, and length of
Clin Oral Implants Res. 2000 Aug;11(4):354-60.
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Biochemical study of human periodontal ligament: preparation of cell
attachment materials induced by pulsed electromagnetic fields.
Department of Oral Biochemistry, Kanagawa Dental College, Japan.
The periodontium, especially the periodontal ligament and alveolar
bone, are tissues constantly subjected to physical stress such as
occlusion and mastication. This study was designed to explore the effect
of the pulsed electromagnetic fields (PEMF) on the cell attachment and
the spread of human periodontal ligament fibroblasts (HPLF) and rat
osteoblasts (ROB). PEMF are categorized as one type of mechanical
stress. HPLF were obtained by the explantation method described by Saito
et al. They were then subcultured in Dulbecco's modified Eagle's medium
(D-MEM) and supplemented with 2 mg/ml dialyzed fetal calf serum protein
(FCSP), 50 micrograms/ml ascorbic acid and penicillin/streptomycin
after trypsinization. ROB were isolated from a two-day-old rat calvaria
by the sequential bacterial collagenase digestion method described by
Dziak and Brand and were subcultured in D-MEM supplemented with FCSP,
ascorbic acid and penicillin/streptomycin. After the confluent HPLF were
cultured with serum-free MCDB 107 medium, the quiescent HPLF were
exposed with or without PEMF for 24 hr. This was followed by the
collection of the control conditioned medium (C-CM) and PEMF exposed
conditioned medium (PEMF-CM). The cell attachment assay was performed so
that the hydrophobic 24 multiwells were coated with the whole
conditioned medium or fractionated conditioned medium by a PO-60K
column. After coating, heat inactivated BSA blocked nonspecific sites
for cell adhesion, and 3H-TdR labeled HPLF or ROB were cultured on the
precoated wells. The activity of cell attachment and spreading was
determined by the radioactivity of 3H-TdR using a scintillation counter.
The characters of cell attachment factors derived from HPLF were
hydrophobic, heat labile and proteolytic enzyme digestible. In addition,
the fractionated PEMF-CM enhanced the spreading activity of ROB. PEMF
induced the 10 KDa which can enhance the HPLF and ROB spreading.
Therefore, the cell attachment and spreading factors secreted by HPLF
exposed with PEMF may regulate HPLF and also ROB.
Bull Kanagawa Dent Coll. 1990 Sep;18(2):89-98.
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Effect of pulsed electromagnetic fields (PEMF) on human periodontal ligament in vitro. Alterations of intracellular Ca2+
Satake T, Yasu N, Kakai Y, Kawamura T, Sato T, Nakano T, Amino S, Ishiwata Y, Saito S.
Department of Oral Biochemistry, Kanagawa Dental College.
The concept of orthodontic tooth movement is based on the hypothesis
that teeth move as a result of the biological response of periodontal
tissues to the mechanical forces applied. There is a widely held
hypothesis that mechanical stress generates an electrical signal which
sets in motion the subsequent events, as in bone exposed to mechanical
forces electrical currents are produced affect bone growth and
remodeling. This implies a transduction mechanism which translates the
electrical signal into a biochemical message, recognizable by the
cellular machine. This study is aimed at the identification of the
message and the investigation of its control. In fact, the effect of
Pulsed Electromagnetic Fields (PEMF) on the intracellular second
messenger, cytoplasmic Ca2+ in Human Periodontal Ligament Fibroblasts
(HPLF) was investigated. The resting intracellular ionized calcium
concentration ([Ca+2]i) of HPLF cells was 232.7 +/- 25.0 nM, and with
PEMF [Ca2+]i increased from 12 hrs to 499.0 +/- 115.5 nM up to 12 hrs,
then reached to a steady level through 24 hrs. The PEMF were also found
to decrease the responses towards epidermal growth factor (EGF) and
serum, when the degree of response was based on the intracellular Ca2+
transient. These effects of PEMF were mimicked by 12-0-tetradecanoyl
phorbol 13-acetate (TPA), a potent activator of protein kinase C. Some
reports have suggested that fibroblasts of the periodontal ligament
contain high alkaline phosphatase (ALPase) activity as much as
osteoblast. Since similar results concerning the [Ca2+]i were obtained
in osteoblast (OB)-like cells, this experiment also supports the
hypothesis that fibroblasts of periodontal ligament have osteoblastic
Kanagawa Shigaku. 1990 Mar;24(4):735-42.
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The use of a permanent magnetic field in the combined treatment of lichen ruber planus of the oral mucosa.
Kupriianova TA, Markov BP, Vilkova LA, Barabash AG.
In 51 patients, the conventional therapy was combined with
application of plate prostheses with samarium-cobalt magnets. Clinical
investigations showed a beneficial effect of the constant magnetic field
on the inflammation relief, erosion epithelialization and papules
disappearing from the oral cavity.
Stomatologiia (Mosk) 1989 Sep-Oct;68(5):33-4
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Magnets and orthodontics.
Sandler PJ, Meghji S, Murray AM, Springate SD, Sandy JR, Crow V, Reed RT.
London Hospital Dental Institute, Whitechapel.
The first part of this paper is a literature review of magnets and
their uses in orthodontics. The biological safety of magnets is
considered and a report is given of experiments carried out on rat
osteosarcoma cell line UMR-106.
The second part of the paper describes a case where
neodymium-iron-boron magnets were used to assist eruption of an
unerupted, vertically impacted upper right canine. Previously, space was
available for this tooth, but it failed to show signs of eruption.
Following surgical attachment of a magnet, and the use of a second
magnet attached to an upper removable appliance, rapid eruption occurred
producing a favourable position for bonding.
Sandler PJ, Meghji S, Murray AM, Springate SD, Sandy JR, Crow V, Reed RT (November 1989). "Magnets and orthodontics." British Journal of Orthodontics. 16(4):243-9. PMID: 2684264
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