Junho Jung

Volume stability of hydroxyapatite and β-tricalcium phosphate biphasic bone graft material in maxillary sinus floor elevation: a radiographic study using 3D cone beam computed tomography.

OBJECTIVES The purpose of this study was to confirm volume stability of biphasic calcium phosphate (BCP) through the changes of grafted volume over the time by 3D CT analyzing software program. PATIENTS AND METHODS Fifteen patients, 16 sinuses who were scheduled a staged implantation through sinus floor elevation (SFE)-lateral window technique from 2009 to 2011 were included in the study. Of the 15 patients, eight were male and seven were female (mean age 50.1). For sinus floor augmentation, BCP with local blood was packed loosely into the maxillary sinus and the grafted site was covered with a collagen membrane. For the evaluation of volume change, 3D CBCT scans were taken five times at pre-operatively (To), post-op 1 week (T1), 1 month (T2), 3 months (T3), and 6 months (T4). 3D image processing software (OnDemand3DTM software) was used for this study. The time sequential change was statistically evaluated. RESULT 84.32% grafted BCP is maintained until post-op 6 month (T4), and the average volume loss is 207.7 mm(3) (about 0.21 cc). Statistically, a significant volume change (decreasing) was observed in three groups (T2-T1, T3-T2, T4-T3). CONCLUSION Biphasic calcium phosphate, as a synthetic material, has high volume stability and is a predictable graft material for the successful SFE. Although some limitations of the 3D analyzing software program, it is a fast, simple, relatively accurate and promising approach to quantifying long-term changes in the grafted area.

Impact of Soft Tissue Pathophysiology in the Development and Maintenance of Bisphosphonate-Related Osteonecrosis of the Jaw (BRONJ)

Since the first description of bisphosphonate-related osteonecrosis of the jaw (BRONJ), numerous research groups have focused on possible pathological mechanisms including the suppression of the bone turnover of the jaw, antiangiogenic effects and soft tissue toxicity. In our review we focused on summarizing the role of the soft tissues in the development and progression of BRONJ. The biological behavior of fibroblasts can be significantly influenced by bisphosphonates (BP) such as a concentration dependent reduction of cell viability. High concentrations of BP can induce apoptosis and necrosis of the cells. Comparable effects could be detected for keratinocytes. Compared to non-nitrogen containing bisphosphonates, nitrogen-containing BP have worse effects on cell biology by blocking the mevalonate pathway. Further, the cell architecture and expression levels of several genes and proteins are significantly disturbed by BP. These inhibitory effects of BP are in accordance with BP-related reduced angiogenesis and neovascularization and could underline the hypothesis that inhibition of fibroblasts and keratinocytes results in delayed wound healing and can induce and trigger BRONJ.

Osteoblastic Differentiation of Functionalized Biphasic Hydroxyapatite and b-Tricalcium Phosphate with Recombinant Human Growth and Differentiation (rhGDF-5)

The purpose of this research was to examine the effect of biphasic hydroxyapatite and b-tricalcium phosphate (HAp-bTCP) immobilized GDF-5 to assess the hypothesis that osteoblast is enhanced and bone formation is promoted when compared to biphasic HAp-bTCP in vitro and in vivo. First, we characterized the release profiles from HAp-bTCP and tested their cell viability, differentiation. After that, we loaded GDF-5 to HAp-bTCP. In the animal study, 4 full thickness critical-size calvarial defects were prepared in a total of 16 male rabbits. The cranial defects were filled with HAP-bTCp, or heparized HAP-bTCP. At 5 and 10 weeks, dissected specimens were processed for histological and histochemical analysis. GDF-5 was considered to be released in a sustained mode from HAp-bTCP. In vitro results provided that the proliferation and differentiation of MG-63 cells to HAp-bTCP-GDF-5 was higher than that of the control group. In addition, in vivo animal studies showed that HAp-bTCP-GDF-5 has a significant improvement to bone formation. HAp-bTCP-GDF-5 is thought to be an excellent biomaterial that delivers osteogenic differentiation factors such as GDF-5, and GDF-5 can be possibly useful as an effective alternative to avail new bone formation.

Three-dimensional volumetric analysis of condylar head and glenoid cavity after mandibular advancement

The aim of this study was to assess condylar resorption, spatial change in glenoid cavity, and its risk factors after mandibular advancement by three-dimensional volumetric analysis. Subjects consisted of 30 condyles of 15 patients diagnosed with mandibular retrognathism who underwent Le Fort I and bilateral sagittal split ramus osteotomy advancement. CBCT images were taken before surgery (T0), immediately after surgery (T1), and postoperatively at 6 months (T2) and 1 year (T3). Condylar resorption was observed in 21 condyles. The posterior was the most affected region, while the anterior was the least affected. The volume of the glenoid cavity was significantly increased after surgery regardless of the presence or absence of resorption. However, the cavity recovered close to its original volume over time. At 1 year after surgery, the volume was not significantly different from the preoperative volume. Counterclockwise rotation of the proximal segment was found to be a risk factor affecting resorption based on correlation analysis. Mandibular advancement appeared to generate excessive mechanical stress on the posterior condyle, and might be responsible for the resorption. Counterclockwise rotation might have added stress to the region. Articular spatial change was transient and did not appear to be related to condyle resorption.

Anti‑inflammatory effect of polydeoxyribonucleotide on zoledronic acid‑pretreated and lipopolysaccharide‑stimulated RAW 264.7 cells

Bisphosphonates are generally used as therapeutic agents for bone diseases. However, previous reports on bisphosphonates-related osteonecrosis of the jaw (BRONJ) demonstrated that inflammation triggers and worsens the disease. Recently, polydeoxynucleotide (PDRN), an A2A receptor agonist, has been suggested for the treatment of various diseases and broadly studied for its anti-inflammatory effect. The present study aimed to measure the effect of PDRN on macrophage cells treated with zoledronic acid (ZA) and lipopolysaccharide (LPS). Macrophage cells were cultured with ZA for 24 h, following which they were stimulated with LPS in the presence or absence of varying concentrations of PDRN for 24 h. The cell viability and nitric oxide (NO) production of the cells were analyzed. In addition, protein expression levels were quantified by western blotting. Cell viability was compromised and NO was overexpressed by ZA and LPS stimulation. However, under ZA and LPS stimulation cell viability was enhanced, and NO production, and inducible nitric oxide synthase, interleukin (IL)-1β, -6, and tumor necrosis factor-α overexpression were suppressed on exposure to PDRN. A2A receptor and vascular endothelial growth factor (VEGF) expression levels increased following PDRN treatment. These results indicate that PDRN treatment of macrophages inhibits the inflammatory cytokines induced by ZA and LPS stimulation. It was hypothesized that the inflammatory cytokines were inhibited through A2A activation by PDRN. In addition, increased VEGF expression may contribute to increased vascularization and subsequently improve the pathological condition in BRONJ. As inflammation and LPS may stimulate the occurrence of BRONJ, the present study postulated that PDRN is possibly a candidate for the therapeutic management of BRONJ by decreasing inflammation and increasing vascularization.

Comparison between anterior segmental osteotomy versus conventional orthodontic treatment in root resorption: a radiographic study using cone-beam computed tomography

BackgroundPatients who received orthodontic treatment are likely to have apical root shortening. It appears that external apical root resorption results from a combination of patient-related risk factors such as genetic influences, systemic factors, and orthodontic treatment-related factors. Regarding the fact that the anterior segmental osteotomy (ASO) has been known for its possibility of complementing external apical root resorption and of buffering periodontal problems, it has been the preferred treatment. However, the studies on the efficacy of ASO in preserving the root are not sufficient. In this study, we compared the amount of root resorption between the patients who only received orthodontic treatment and the patients who received orthodontic treatment with ASO.MethodsThis study included 28 patients (the number of incisor = 198) who received orthodontic treatment with or without ASO. We categorize them into groups A and B by the type of orthodontic treatment (group A: conventional orthodontic treatment; group B: orthodontic treatment with ASO). Cone-beam computed tomographic and cephalometric evaluations were retrospectively performed on the radiographs taken for the diagnosis of the treatment before treatment and at the end of active treatment.ResultsIn group B, root resorption itself and its rate both turned out to have significantly lower than those in group A. Also, the change of incisal angle is significantly smaller in group B than in group A. On the other hand, in group A, the change of incisal angle was positively correlated with the change of AP (anteroposterior) position. In group B, the change of incisal angle was negatively correlated with the duration of the orthodontic treatment. In group B, amount of root resorption (mm) was positively correlated with the duration of the orthodontic treatment.ConclusionsThe results show lesser root resorption and shorter treatment duration with ASO than with conventional orthodontic treatment. Therefore, if the indications are accurately determined, ASO can be an effective treatment option when the amount of root resorption is expected to be high, especially in late adults.