Hakan Hamdi Celik

The aim of the study was to evaluate the surface areas and volumes of HyFlex EDM (HEDM) nickel-titanium (NiTi) files before and after multiple uses in mandibular molar root canal preparation. Twelve HEDM files with sizes of 10/.05 and 25/.08 were evaluated by micro–CT before and after a single use or multiple uses in root canal preparation. The mesiobuccal and mesiolingual root canals of thirty-six human mandibular molar teeth were instrumented using twelve 10/.05 (300 rpm and 1.8 Ncm) and twelve 25/.085 Ncm) HEDM files according to the manufacturer's recommendation. HEDM files were evaluated using micro–CT at four different timelines: 1) Intact file, 2) After instrumentation of one canal, 3) After instrumentation of two canals, and 4) After instrumentation of three canals. Each group's volume and surface area were analyzed by applying Friedman's test. Each group comparison was assessed using the Wilcoxon signed-rank test with Bonferroni correction. Intact HEDM 10/.05 and HEDM 25/.08 files showed significantly larger volumes and surface areas compared to the used instruments (p < 0.05). A significant decrease in the volume and surface area of the NiTi files was observed as the number of uses increased regardless of the file group. These findings emphasize the importance for clinicians to understand the structural changes in HEDM files during repeated use to ensure safe instrument reuse and prevent endodontic treatment failure.

Purpose The aim of the present study was to evaluate the effectiveness of carbon nanotubes (CNTs)/ HA–tricalcium phosphate (TCP) composite in a posterolateral spinal fusion model. Methods At first, CNTs and CNTs/HA–TCP composites were prepared. Twenty adult male Sprague Dawley rats were randomized into four groups with five rats in each group. Decortication was carried out in standard manner in all animals. Group 1 (only decortication), group 2 (CNTs), group 3 (HA–TCP) and group 4 (CNTs/HA–TCP) were formed. Eight weeks later, all animals were killed and obtained fusion segments were evaluated by manual palpation, histomorphometry and micro-computed tomography (mCT). Results In all evaluations, highest fusion values were obtained in Group 4. In mCT investigations, bone volume/ tissue volume (BV/TV) ratio was found to be significantly higher in composite group (group 4) only compared to ceramic group (group 3) (p < 0.001). Although in Group 2, in which only CNTs were used, the ratio was found to be statistically significantly higher than group 1(p < 0.001), the difference was not considered as significant in terms of fusion and in addition in group 2, CNTs were completely surrounded by fibrous tissue, i.e., no bone formation was observed. Conclusions The CNTs/HA–TCP composite is a promising synthetic bone graft substitute for spinal fusion. Although CNTs are inadequate in producing spinal fusion when they are used alone, due to their high biocompatibility due to their high biocompatibility, and multiple effect on bone regeneration, they seem to increase fusion rates significantly when they are used in combination with ceramic-based synthetic grafts.

Kiraz G, et al. Restor Dent Endod. 2023 Oct;48:e36. https://doi.org/10.5395/rde.2023.48.e36

Background/aim: We have evaluated the effects of taurine and aqueous garlic extract (AGE) as a dietary supplement on osteoporotic fracture (OPF) healing in the ovariectomized rat femur fracture model. Materials and methods: In this experimental animal study,twenty-four osteoporosis-remodeled female Wistar albino rats were randomly divided into 3 groups (n: 8) according to their supplemented diet; control, taurine, and AGE groups. Unilateral femur middiaphysis mini-open osteotomy was stabilized with Kirschner wires. Six weeks after osteotomy, the rats were sacrificed before the femurs were harvested and OPF healing was evaluated with biochemical, histologic, microcomputed-tomography, and scintigraphic methods. Results: As an indicator of the antiosteoporotic effect, the calcium levels of the taurine group were significantly lower than the AGE and control groups in biochemical analyzes (p < 0.01). In histological studies, the new bone diameter and new bone volume values of the taurine group were significantly higher than the control group (p = 0.002 and p = 0.032, respectively), while higher trabecular-compact callus was observed in the taurine and AGE groups, respectively, compared to the control group. In morphological analyses, taurine and AGE groups had significantly higher bone volume/tissue volume, trabecular number, bone surface density, and lower trabecular separation than the control group (p < 0.05). The scintigraphic imaging showed a significant increase in osteoblastic activity of the taurine group compared to the control group (p = 0.005). Conclusion: Taurine and AGE have positive anabolic effects, respectively, on the healing of OPFs, demonstrated by biochemical, histological, morphological, and scintigraphic methods.

Background/aim: Guided bone regeneration (GBR) is commonly performed to repair bone defects, and rigid occlusive titanium barriers play a vital role in bone formation in regions with no prior bone tissue. The statin, rosuvastatin (RSV), strongly affects bone apposition when applied locally. Here, we aimed to evaluate the anabolic effects of locally applied RSV with a xenograft placed on rabbit calvaria. Materials and methods: Two rigid occlusive titanium caps were used in 16 rabbits after decorticating the calvarial bone. In the control group, the area under the cap was filled with a xenograft, while in the RSV group, a xenograft in combination with RSV (1 mg) was used. In both groups, at 6 and 12 weeks, new bone, residual graft, soft tissue areas, and histological and radiological bone volume were evaluated. Results: At 12 weeks, histologically, the RSV group exhibited superior new bone proportion values, and radiologically, new bone and total bone volume in the RSV group were significantly higher than in the control group (p < 0.05); there were no significant differences at 6 weeks (p > 0.05). Conclusion: According to our results, RSV applied locally under a titanium barrier on an area to be repaired with bone grafts increases new bone and total bone volume.

Introduction A recent histopathological and immunohistochemical study has proved that the addition of concentrated growth factors (CGF) to the Masquelet’s technique contributes to the quality of the membrane formed, in respect of inducing inflammation and proliferation, maintaining vascularization on large diaphyseal bone defects, and increasing the number of stem cells. The aim of the study is comparison of radiological results of this combination treatment by micro-CT. Materials and methods The study was planned on a critical bone defect model in rabbit radius. Group I and Group III were the control groups to which only the Masquelet’s technique is applied. Group II and Group IV were CGF groups in addition to the Masquelet’s technique. CGF was prepared by centrifugation of rabbit’s own blood. For early phase, Groups I and II were evaluated in the 8th week, while for late phase, Group III and Group IV were evaluated in the 12th week. Groups were compared in terms of bony union radiologically by micro-CT(μCT) (New Bone Volume (NBV), Total Bone Volume (TBV) and NBV/TBV) and histopathologically. Results The structural parameters, including NBV, TBV, NBV/TBV were higher in the early- (8th week) and late-phase (12th week) CGF group. There was no statistically significant difference between CGF and control groups in early phase, (p = 0.153), while in late phase, CGF group was significantly higher of new bone volume than the control group, 246.3 mm³ (196.1–258) and 169.6 mm³ (154.3–235.9), respectively (p = 0.028). For early phase, control group was significantly lower than late-phase control group, 121.8 mm³ (88.8–144.4) and 169.6 mm3 (154.3–235.9), respectively (p = 0.006). The ratio of New Bone Volume to Total Bone Volume (NBV/TBV ratio) in CGF groups was significantly higher compared to the control groups 27.3% (24.7–29.6), 35.3% (32.1–38.6) (p = 0.032) and 39.7% (36.7–41.6), 55.3% (52–57.5) (p = 0.002), respectively. Histopathologically, Microscopic New Bone Formation had no statistically significant difference between control and CGF groups in early phase (8th week) (p = 0.153), while in late phase (12th week), CGF group had significantly higher amount of new bone formation than the control group, 0.29 µm² (0.27–0.36), 0.51 µm² (0.42–0.59), respectively (p = 0.008). Conclusion The addition of CGF to the Masquelet’s technique is an important method for supporting new bone formation in large diaphyseal bone defects. Level evidence Level III, therapeutic/care management.

Objective The aim of this study was to investigate the effects of human recombinant epidermal growth factor (EGF) on posterolateral lumbar fusion in a rat model. Methods 36 male Sprague Dawley rats underwent posterolateral fusion at L4-5 level. They were randomly assigned to 3 groups: 1- Sham control group where no local augmentation was made, 2- Local Hydoxyapatite ß-tricalcium phosphate (HA/ß-TCP) augmentation group and 3- Local HA/ß-TCP + EGF augmentation group. Rats were euthanized at 8 weeks post-surgery. 6 rats from each group were selected for manual palpation examination, micro-computed tomography analysis and histologic analysis; and the rest was used for biomechanical analysis. Results Based on manual palpation, there was no fusion in the sham control group. Fusion rate was 33.3% in the HA/ß-TCP group and 66.7% in the HA/ß-TCP + EGF group (p = 0.085). Micro-CT results revealed that new bone formation was higher in the HA/ß-TCP + EGF group (BV/TV: 40% vs. 65%) (p = 0.004). Histologically newly formed bone tissue was more pronounced in the EGF group and compacted and bridging bone spicules were observed. The median maximum bending moment values were 0.51 Nmm (0.42–0.59), 0.73 Nmm (0.49–0.88) and 0.91 Nmm (0.66–1.03) in the sham control, HA/ß-TCP and HA/ß-TCP + EGF groups, respectively (p = 0.013). The median stiffness values were 1.69 N/mm (1.12–2.18), 1.68 N/mm (1.13–2.74) and 3.10 N/mm (1.66–4.40) as in the previous order (p = 0.087). Conclusion This study demonstrates that EGF enhances posterolateral lumbar fusion in the rat model. EGF in combination with ceramic grafts increased the fusion rates. Our findings may provide insights to further studies, investigating EGF's clinical usage as an alternative fusion enhancer. ER -

To performed a histomorphometric and radiological study to evaluate the effects of alendronate sodium administered locally in mandibular bone defects created in rabbits. Two circular defects 5 mm in diameter were created bilaterally in the mandibular corpus of 20 New Zealand rabbits (i.e., four defects per animal). Each defect received one of four treatments: no treatment (EC group), alendronate irrigation (AL group), autogenous bone grafting (AG group), or alendronate irrigation with autogenous bone grafting (AL+AG group). Histomorphometric and radiological assessments were conducted at 4 and 8 weeks after surgery. Between-group comparisons of the new bone area, the value of the AL+AG group was significantly lower thanthe remaining three groups at 4 weeks postoperatively. In all groups, the new bone area was significantly larger at 8 weeks than at 4 weeks. The residual graft area at 4 and 8 weeks was significantly higher in the AL+AG group than in the AG group, although it was significantly smaller at 8 weeks than at 4 weeks in both these groups. The use of alendronate sodium in conjunction with autogenous bone grafting improves the osteoconductive properties of the graft, enhances graft retention in the defect, and improves ossification.