Role of interleukin-4 in pathogenesis of oral lichen planus: A systematic review.

BACKGROUND: Oral lichen planus (OLP) is a premalignant mucocutaneous disease that affects 1-2% of the adult population. Immunological factor may act as etiological factor. The cellular immune cells such as T cells are important in pathogenesis of OLP. Interleukin-4 (IL-4) is secreted by T-helper 2 (Th2). Several studies have been carried out on the role of IL-4 in OLP. The aim of this study was to review the level of IL-4 in OLP, effective factors in the production of IL-4 and its role in the development of OLP. MATERIAL AND METHODS: A search in PubMed was performed on the literature published from 2000 until august 2019 using the following keywords: "oral lichen planus" or "OLP" and "interleukin-4" or "IL-4". RESULTS: Originally, 37 articles were considered, of which 28 case-control articles were selected according to the inclusion/exclusion criteria. CONCLUSIONS: This review study shows that IL-4 plays a key role in the development of OLP. According to the past studies, there are several factors contributing to the production of this cytokine. Identification of the routes of production of IL-4 and its role in OLP might be useful for development of new preventive and therapeutic methods in management of patients with OLP.

Comparison of lateral window and osteotome techniques in sinus augmentation: histological and histomorphometric evaluation.

OBJECTIVE: The aim of this study was to compare the lateral window and osteotome techniques for sinus lifting using histological and histomorphometric methods. MATERIALS AND METHODS: In this clinical trial 10 patients (a total number of 14 sinus areas) who needed implant treatment in the atrophic posterior maxilla were enrolled. In all the cases the residual bone height between the sinus floor and the alveolar crest was less than 5 mm. Sinus augmentation was performed. The treatment modality for a given residual bone height was selected randomly and Bio-Oss was applied in all the cases as the graft material. After a healing period of about 10 months, in all the cases, the implants were placed and biopsies of alveolar crestal bone were obtained at the same time; biopsy specimens were evaluated using histological and histomorphometric methods. Fisher's exact and Mann-Whitney U tests were used to compare distribution of variables in the two groups. Statistical significance was defined at P<0.05. RESULTS: The new bone was located in direct contact with the biomaterial without any gaps. This viable bone consisted of lacunae containing osteocytes. Infiltration of inflammatory cells did not exhibit any significant differences between the two techniques. Foreign body reaction was not observed in any cases. Histomorphometric evaluations demonstrated that The mean values of the new bone in the lateral window and osteotome techniques were 30±6.0 and 25.2±5.2, respectively, with no significant differences between the two groups.. Moreover, the average quantity of residual biomaterial and connective tissue were similar for the two groups. CONCLUSION: The nature and the volume of the new bone in lateral window and osteotome techniques were the same.

Evaluation of the Effect of Plasma Rich in Growth Factors (PRGF) on Bone Regeneration.

OBJECTIVE: Reconstruction methods are an essential prerequisite for functional rehabilitation of the stomatognathic system. Plasma rich in growth factors (PRGF) offers a new and potentially useful adjunct to bone substitute materials in bone reconstructive surgery. This study was carried out to investigate the influence of PRGF and fibrin membrane on regeneration of bony defects with and without deproteinized bovine bone mineral (DBBM) on rabbit calvaria. MATERIALS AND METHODS: Twelve New Zealand white rabbits were included in this randomized, blinded, prospective study. Four equal 3.3×6.6 mm cranial bone defects were created and immediately grafted with DBBM, PRGF+DBBM, PRGF+fibrin membrane and no treatment as control. The defects were evaluated with histologic and histomorphometric analysis performed 4 and 8 weeks later. RESULTS: Adding PRGF to DBBM led to increased bone formation as compared with the control group in 4- and 8-week intervals. In DBBM and PRGF+fibrin membrane samples, no significant increase was seen compared to the control group. There was also a significant increase in the rate of biodegradation of DBBM particles with the addition of PRGF in the 8-week interval. Neither noticeable foreign body reaction nor any severe inflammation was seen in each of the specimens evaluated. CONCLUSION: Under the limitation of this study, adding PRGF to DBBM enhanced osteogenesis in rabbit calvarias. Applying autologous fibrin membrane in the defects was not helpful.