Foreign body gingival lesions: distribution, morphology, identification by X-ray energy dispersive analysis and possible origin of foreign material
Altered CD40 and E-cadherin expression – putative role in oral lichen planus  



Foreign body gingival lesions: distribution, morphology,
identification by X-ray energy dispersive analysis and possible origin of foreign material

Journal: Journal of Oral Pathology and Medicine

Citation: Journal of Oral Pathology & Medicine 36 (3), 161–172

Authors: Hanna Strømme Koppang, André Roushan, Ali Srafilzadeh, Steinar Ørbeck Stølen, Rolf Koppang
Background: Foreign material may cause and aggravate gingival lesions. This is rarely considered clinically. The lesions
are resistant to frequently protracted conventional therapy. The foreign material is often inconspicuous and easily
overlooked by the pathologist.

Methods: 85 cases of gingival lesions containing foreign material were investigated by conventional and polarization light
microscopy, focusing on the morphology and optical characteristics of the foreign substance. Supplemented with the results
of X-ray energy dispersive analysis the foreign material was compared with commonly used dental materials.

Results: The foreign material was most frequently compatible with amalgam. Inconspicuous crystals, often revealed only by
polarization microscopy, were most commonly compatible with abrasives, particularly corundum and silicates, and mostly
occurred together with amalgam dust.

Conclusions: Iatrogenic introduction of dental materials during dental procedures explains most foreign body gingival
lesions which could be reduced or avoided by prophylactic measures. Pathologists should meticulously scrutinize gingival
biopsies routinely applying polarization microscopy

Altered CD40 and E-cadherin expression – putative role in oral lichen planus  
 
Journal: Journal of Oral Pathology and Medicine 

Citation: Journal of Oral Pathology & Medicine 36 (3), 153–160

Authors: E. Neppelberg, L. L. Loro, G. Øijordsbakken, A. C. Johannessen
Background: Oral lichen planus (OLP) is characterized among other features by apoptosis of basal keratinocytes. To identify potential regulatory mechanisms associated with basal cell apoptosis in OLP, we investigated the expression of CD40, CD40 ligand (CD40L), CD44 and epithelial (E)-cadherin.

Methods: Biopsies from 22 patients with OLP were investigated by immunohistochemistry for detection of CD40, CD40L, E-cadherin, CD44, Laminin-5 and Collagen IV, double-labelling for CD40 and CD3, and in situ mRNA hybridization for CD40 and CD40L.

Results: In actively diseased areas of OLP lesions, basal keratinocytes did not express CD40 and were focally E-cadherin-negative, in contrast to non-diseased areas and normal oral mucosa. Demonstration of intraepithelial T cells expressing CD40 and CD40L, indicates a potential role in inflammatory cell responses involved in the disease process of OLP.

Conclusion: T cells may orchestrate inflammatory cell responses in OLP via CD40–CD40L interactions. As basal keratinocytes downregulate CD40, they may escape CD40–CD40L-induced apoptosis in OLP. On the other hand, loss of E-cadherin expression may contribute to epithelial basal cell destruction and T-cell migration into the epithelial compartment in OLP.