Oral Lichen planus is a relatively common disease of the oral mucosa that involves
the cell-mediated arm of the immune system. According to the studies on different
populations, it has a prevalence of about 0.1 to 4% (Lind
et al., 1986; Ditrichova et al., 2007).
The various terms for oral lichen planus in the literature are oral lichenoid
reactions, lichenoid contact lesions and lichenoid contact stomatitis and are
used interchangeably, which is confusing. The similarity which exists between
oral lichen planus and the lesions caused by reaction to some materials and
drugs suggests the use of lichenoid reactions in this study. According to results
achieved by earlier studies a relationship between lichenoid reactions and amalgam
fillings exists (Ostman et al., 1994; Laeijendecker
et al., 2005). Despite the fact that lichenoid reaction often occur
after amalgam fillings, it seems necessary to investigate lichenoid lesions
improvement as a result of amalgam fillings removal. Furthermore, this study
is the first one in Iranian patient with lichenoid reaction.
MATERIALS AND METHODS
This was a before-after study and patients were randomly selected from those who referred to Dental School, Tehran University of Medical Sciences. Twenty patients with Lichenoid reactions which were next to the amalgam fillings were enrolled in this study during September 2006 to November 2007. All patients had clinically and histologically confirmed diagnosis of OLP by WHO criteria. All participants took part in the study after giving written informed consent according to institutional guideline of ethics committee.
Inclusion criteria’s of this study were: amalgam fillings next to the
Lichenoid reactions; minimal interval of 3 months between amalgam filling therapy
and occurrence of the lesion; not having an autoimmune disease; no use of lichenoid
causing drugs in the past 3 months and ;no sign of graft versus host disease.
The longest diameter of lesions was measured by a scaled tongue blade before and 3 months after amalgam fillings removal. After amalgam removal, all cavities were filled with composite. All participants took part in the study after giving written informed consent according to institutional guidelines of ethics committee.
The results of clinical improvement of lesions were assessed based on the following criteria; Having no change after amalgam removal attributed to no improvement; decrease of 5 mm or less in diameter attributed to partial improvement; decrease of more than 5 mm attributed to complete improvement.
The burning sensation of these lesions was determined by VAS (visual analogue scale). Patients were asked to give a number to the burning sensation before and after intervention. This symptom was ranked based on the following criteria; no decrease of burning sensation: no improvement; decreases of less than 5 degrees: partial improvement; decreases of 5 or more than 5 degrees: complete improvement.
In order to avoid further inconvenience, the patient in whom the amalgam fillings removal could endanger the teeth vitality were excluded from the study and if there were more than one filling next to the lesion (e.g., 3 fillings in the lower jaw or 2 in the lower and 3 on the upper arch) they were completely replaced by composite. The interval of 3 months have been chosen because the time needed to reveal the effect of amalgam fillings removal on lichenoid reactions is 2 to 3 months (Wong et al., 2003). The results were analyzed using SPSS11 software.
RESULTS AND DISCUSSION
Among 20 cases, which entered our study, 19 completed the treatment process including replacing amalgam fillings with composite and a 3-month follow up. Patients’ Mean age was 45.6 with a minimal age of 21 and maximum age of 62.
The most common sites were buccal (47%), gingiva (26%) tongue (21%) and lip (5%).
Mean interval between lichenoid reactions occurrence and oldest amalgam fillings was 22 months with a minimal range of 3 months and maximum range of 60 months.
Mean size of lesions was 19.37±6.24 mm before intervention and 13±8.52
after intervention, which showed a significant difference between lesion size
before and after intervention (p = 0.002). Table 1 demonstrates
improvements according to lesions’ size.
Mean burning sensation of lesions was 5.26±1.36 before intervention and 2.95±2.17 after intervention, which demonstrated a significant decrease of this symptom after amalgam fillings removal (p = 0.001). Table 2 demonstrates improvement of burning sensation improvement in lesions of studied patients.
Close contact to amalgam fillings causes the raising of lichenoid reactions
that are clinically and histologically very similar to lichen planus but the
etiology of the first one is well determined. These oral lesions are probably
the result of allergic reaction to leaking products and/or plaque accumulation
on dental fillings. In this study 19 cases of oral lichen planus like lesions
were examined in a period of one and a half year. The treatment plan included
replacing amalgam fillings with composite 3 months follow up.
||Frequency of lesion improvement (size reduction-sign) in studied patients
p = 0.002
||Frequency of burning sensation improvement (symptom) in lesions of studied
patients (p = 0.001)
p = 0.001
it was revealed that replacing amalgam fillings with composite results in a
significant difference in lesions size reduction (p = 0.002) and improvement
of burning sensation (p = 0.001). This completely supports our assumption achieved
by years of clinical experience (the occurrence of lichen-planus like lesions
next to the amalgam fillings).and a 3 months follow up. After intervention it
was revealed that replacing amalgam fillings with composite results in a significant
difference in lesions size reduction (p = 0.002) and improvement of burning
sensation (p = 0.001). This completely supports our assumption achieved by years
of clinical experience (the occurrence of lichen-planus like lesions next to
the amalgam fillings).
In a similar study, in 52 patients with oral lichen planus topographically
related to amalgam restorations, other materials replaced the fillings in 18,
16 of whom experienced complete remission of the lesions within 1-12 months.
These results are discussed in relation to the results of epicutaneous patch
tests for possible allergy to a number of mercury compounds. The term oral lichenoid
reaction is suggested to describe these lesions (Lind et
al., 1986). The results of the present study are in the same path, as
mentioned before in our study 3 cases (16%) showed complete improvement and
8 cases (42%) revealed partial improvement. Although previous studies suggest
a follow up period of 2 to 3 months to eliminate lichenoid signs, maybe we could
gain more reliable results if the patients were to be monitored for a longer
In another study, amalgam fillings were replaced by composite to determine
contact allergies in patients with oral lichen planus and to monitor the effect
of partial or complete replacement of amalgam fillings following a positive
patch test reaction to ammoniated mercury, metallic mercury, or amalgam. In
group A (20 patients), the oral lesions were confined to areas in close contact
with amalgam fillings. In group B (20 patients), the lesions extended 1 cm beyond
the area of contact with amalgam fillings. In group C (20 patients), the oral
lesions had no topographic relationship with amalgam fillings. Partial or complete
replacement of amalgam fillings was recommended if there was a positive patch
test reaction to ammoniated mercury, metallic mercury, or amalgam. Amalgam fillings
were replaced in 13 patients of group A, with significant improvement. Dental
amalgam was replaced in 8 patients of group B, with significant improvement.
In group C, amalgam replacement in 2 patients resulted in improvement in 1 patient.
These results were evaluated after 3 months. Contact allergy to mercury compounds
is important in the pathogenesis of oral lichen planus, especially if there
is close contact with Amalgam fillings and if no concomitant cutaneous lichen
planus is present. In cases of positive patch test reactions to mercury compounds,
partial or complete replacement of amalgam fillings will lead to a significant
improvement in nearly all patients. These results are similar to what we achieved
in our study (16% of complete improvement and 42% of partial improvement). In
a study conducted by Wong et al. (2003) (39Yo)
patients had positive patch test findings. 30/33 patch test positive patients
had replacement of their amalgam fillings, with 28 (87Yo) patients experiencing
improvement of symptoms and signs within 3 months. This confirms that mercury
allergy is a factor in the pathogenesis of OLL in some cases. In cases where
patch test negative patients improve with amalgam replacement, mercury may be
acting as an irritant in the pathogenesis of OLL (Wong and
The purpose of another similar study was to investigate the relationship between
amalgam restorations and oral lichen planus. Eighty-one patients with oral lichenoid
lesions were characterized clinically and skin patch tested for amalgam or mercury
hypersensitivity. Thirty-three of these patients had amalgam fillings in contact
with oral lesions replaced and were followed to determine the outcome. Clinically,
2 patient groups were identified: (1) 30 patients with probable amalgam-contact
hypersensitivity lesions (ACHLs) and (2) 51 patients with Oral Lichen Planus
(OLP) but no clear relationship with amalgam. Amalgam replacement resulted in
lesion improvement in 93% of ACHL cases. No such improvement was observed in
the OLP cases treated (p<0.001). OLP is a heterogeneous condition within
which an ACHL subgroup can be identified. ACHLs, but not other OLP lesions,
respond favorably to amalgam replacement. A strong clinical association between
lesions and amalgam restorations plus a positive patch test result was a good
predictor of lesion improvement on amalgam replacement (Thornhill
et al., 2003). As in present study we only chose patients with close
contact to amalgam fillings.
The pathogenetic relationship between Oral Lichenoid Reactions (OLR) and dental
amalgam fillings is still a matter of controversy. To determine the diagnostic
value of patch tests with amalgam and inorganic mercury (INM) and the effect
of amalgam removal in OLR associated with amalgam fillings this other study
was performed by DONSCHE A. in this study, amalgam removal led to benefit in
97.1% patients, of whom 29.5% were cured completely. Of all patients with OLR
associated with dental amalgam fillings, 97.1% benefited from amalgam removal
regardless of patch test results with amalgam or INM (Dunsche
et al., 2003). This study shows that the removal of amalgam fillings
can be recommended in all patients with symptomatic OLR associated with amalgam
fillings. Results of the present study support other studies investigated the
causative relation of lechenoid reactions and amalgam fillings.
Overall, the results of this study proved that the replacement of dental amalgam fillings with composite could contribute to improvement of sign and symptoms of some OLP patients. Yet, further studies are needed in the field of pathophysiologic procedure of these lesions and their relation to amalgam fillings.