HLA-DRB and HLA-DQA/HLA-DQB allele and haplotype frequencies in Iranian patients with aggressive periodontitis.

BACKGROUND AND OBJECTIVE: Genetic backgrounds play a key role in susceptibility to and protection against a spectrum of periodontal diseases. Like other infectious diseases, the human leukocyte antigen (HLA) have been found to be associated with periodontitis. This study aimed to investigate differences in allele and haplotype frequencies of HLA class II antigens in a sample of Iranian patients with aggressive periodontitis compared with a healthy control group. MATERIAL AND METHODS: Fifty unrelated patients with aggressive periodontitis and 130 healthy volunteers were enrolled in this study. HLA genotyping for HLA-DRB, HLA-DQA1 and HLA-DQB1 was performed using the PCR with sequence-specific primers. Allele and haplotype frequencies were compared across groups. RESULTS: The frequencies of HLA-DQA1*03:01, HLA-DQB1*03:02 and HLA-DQB1*03:05 alleles, as well as that of the HLA-DRB1*04:01 allele, were significantly higher in patients with aggressive periodontitis compared with control subjects (p = 0.01, p = 0.04, p = 0.05 and p = 0.04, respectively). In contrast, the frequency of the HLA-DQB1*0603 allele was significantly lower in patients with aggressive periodontitis compared with control subjects (p = 0.006; odds ratio = 0.20). With regard to haplotype association, a significantly higher frequency of two haplotypes - HLA-DRB1*04:01/HLA-DQA1*03:01/HLA-DQB1*03:02 and HLA-DRB1*16:01/HLA-DQA1*01:03/HLA-DQB1*05:01 - was observed in patients with aggressive periodontitis compared with healthy controls (p = 0.01, odds ratio = 2.56 and p = 0.05, odds ratio = 5.38, respectively). CONCLUSION: These results provide additional evidence that class II HLA polymorphisms, particularly in the DQ locus, are associated with protection against and susceptibility to aggressive periodontitis.

Histologic Evaluation of Bone Healing Following Application of Anorganic Bovine Bone and ß-tricalcium Phosphate in Rabbit Calvaria.

OBJECTIVE: Both anorganic bovine bone (ABB) and ß-tricalcium phosphate (ß-TCP) are used in clinical practice as bone substitute materials, but there is limited data comparing these two materials in standardized defects. The aim of this study was to histologically evaluate the effectiveness of ABB and ß-TCP in the healing of experimentally induced bone defects. MATERIALS AND METHODS: Eighteen bone defects were created on the calvaria of six rabbits. In each animal, one defect was left untreated and the other two were filled with ABB and ß-TCP. After one month, histological sections were prepared. Type and vitality of newly formed bone, percentage of new bone formation and residual material, thickness of trabeculae, inflammation and foreign body reaction were assessed. RESULTS: The newly formed osseous tissue was vital in all defects and consisted of woven and lamellar bone. Mean percentages of new bone formation were 30.83±14.29%, 16.83±11.07% and 14.00±8.17% in ß-TCP, ABB and control groups, respectively and the mean percentages of residual biomaterial were 24.17±14.01% and 36.50±8.43% in ß-TCP and ABB groups, respectively. However, the differences were not statistically significant (all ps>0.05). Inflammatory infiltration was statistically higher in ß-TCP compared to the control group (p=0.025), but the difference was not significant between ß-TCP and ABB groups (p=0.083). Trabeculation thickness and foreign body reaction were not statistically different between ß-TCP and ABB groups. CONCLUSION: ß-TCP and ABB were not different with regard to the quantity and quality of newly formed osseous tissue. However, inflammatory infiltration was higher in sites filled with ß-TCP.

The influence of low-intensity laser therapy on bone healing.

OBJECTIVE: Low-intensity laser therapy (LILT) is defined to supply direct biostimulative light energy to the cells. While several studies have demonstrated that LILT has stimulating effects on bone cells and can accelerate the repair process of the bone, others reported delayed fracture healing or no effects after LILT. The aim of this article was to review the studies evaluating the biomodulation effects of LILT on bone-derived stem cells. MATERIALS AND METHODS: To access relevant articles, searching in three electronic databases including PubMed, Google Scholar and Science Direct was conducted until April 2012. The key words used were low-level laser, low-intensity laser, low-power laser therapy, stem cell, bone marrow stem cell, bone and osteoblast. The articles that met the eligibility criteria were included in this review of literature. RESULTS: Twenty-five relevant articles (13 in vitro and 12 animal studies) were included. Eleven in vitro studies showed positive results with regard to acceleration of cell proliferation and differentiation. All animal studies showed improved bone healing in sites irradiated with low-intensity laser. CONCLUSION: Based on the results of the reviewed articles, low intensity laser therapy can accelerate bone healing in extraction sites, bone fracture defects and distraction osteogenesis, provided proper parameters were applied.