Comparative study of volumetric changes and trabecular microarchitecture in human maxillary sinus bone augmentation with bioactive glass and autogenous bone graft: a prospective and randomized assessment

The aim of this study was to compare the volumetric changes and the new bone microarchitecture in human maxillary sinuses augmented with bioactive glass (Biogran) alone, bioactive glass combined with autogenous bone graft (1:1), or autogenous bone graft alone. Twelve maxillary sinuses were grafted with bioactive glass (group 1), nine with bioactive glass mixed with autogenous bone graft 1:1 (group 2), and 12 with autogenous bone graft (group 3). Patients underwent cone beam computed tomography 15 days after the procedure to determine the initial volume of the graft (T1) and again 6 months later (T2). Biopsies were obtained at the time of dental implant placement and were subjected to micro-computed tomography. The volumetric change was 44.2% in group 1, 37.9% in group 2, and 45.7% in group 3 (P > 0.05). The trabecular microarchitecture results showed that the materials used in groups 1 and 2 were good bone substitutes. However, the addition of 50% bioactive glass to autogenous bone graft improved the microarchitecture of the graft. Furthermore, the results for volumetric changes indicated that bioactive glass, its association with autogenous bone graft in a 1:1 ratio, and autogenous bone graft alone have similar resorption.     

S-nitroso albumin enhances bone formation in a rabbit calvaria model

Nitric oxide (NO) is a mediator involved in bone regeneration. We therefore examined the effect of the novel NO donor, S-nitroso human serum albumin (S-NO-HSA) on bone formation in a rabbit calvaria augmentation model.Circular grooves (8 mm diameter, two per animal) were created by a trephine drill in the cortical bone of 40 rabbits and titanium caps were placed on the rabbit calvaria bone filled with a collagen sponge soaked with either 100 μL S-NO-HSA (5%, 20%) or human albumin (5%, 20%). After 4 weeks the titanium hemispheres were subjected to histological and histomorphometric analysis. Bone formation and the volume of the residual collagen sponge were evaluated.S-NO-HSA treatment groups had a significantly higher volume of newly formed bone underneath the titanium hemispheres compared to the albumin control groups (5%: 15.5 ± 4.0% versus 10.6 ± 2.9%; P < 0.05; 20%: 14.0 ± 4.6% versus 6.0 ± 3.8%; P < 0.01). The volume of residual collagen sponge was also significantly lower in the S-NO-HSA groups compared to the control groups (5%: 0.4 ± 0.5% versus 2.6 ± 2.4%; P < 0.05 and 20%: 1.5 ± 2.7% versus 13.0 ± 18.7%; P < 0.01).This study demonstrates for the first time that S-NO-HSA promotes bone formation by slow NO release. Additionally, S-NO-HSA increases collagen sponge degradation.     

Apical U-shape splitting technique for undercut areas of the anterior alveolar ridge: a prospective non-randomized controlled study

The aim of this study was to investigate a novel apical U-shape splitting technique for horizontal bone augmentation in undercut areas and to compare its efficacy with that of guided bone regeneration (GBR). This was a prospective non-randomized controlled clinical trial. A total of 36 patients, who presented with a labial undercut that was not able to house a normally inclined implant, underwent the new technique or GBR. Radiographic and clinical data were obtained preoperatively, immediately after surgery, and 12 months after surgery. Pairwise comparisons of changes in ridge width gain, marginal bone loss, and pink aesthetic score were performed; correlations with pristine ridge morphology were investigated. The results showed similar marginal bone loss in the two groups. The overall ridge width gains in the new technique group (2.56 ± 1.92 mm) and GBR group (0.73 ± 1.21 mm) differed significantly (P < 0.05). The pink aesthetic score was higher for the new technique group (11.75 ± 1.22) than for the GBR group (9.25 ± 1.86) (P < 0.01). The morphology of the concavity had different impacts on regeneration in the two groups. The apical U-shape splitting technique, as a safe and effective alternative to GBR, provided a significant increase in bone volume gain where labial fenestration was inevitable during implant placement.     

Does platelet-rich fibrin increase the stability of implants in the posterior of the maxilla? A split-mouth randomized clinical trial

The effect of platelet-rich fibrin (PRF) on bone healing around dental implants in areas of poor bone quality has not been studied. The aim of this study was to evaluate the stability of implants placed in the posterior maxilla, with or without the use of PRF, during the healing period. A split-mouth randomized clinical trial was performed. Twenty patients with missing teeth in the molar region of the maxilla, requiring bilateral implants, were included. PRF was used on one side (group 1); no PRF was used on the other (group 2). Implant stability was assessed by resonance frequency analysis (RFA) at 2, 4, and 6 weeks after placement. At 2 weeks, the mean ISQ was 60.60 ± 3.42 in group 1 and 58.25 ± 3.64 in group 2; at 4 weeks it was 70.30 ± 3.36 in group 1 and 67.15 ± 4.33 in group 2; at 6 weeks it was 78.45 ± 3.36 in group 1 and 76.15 ± 2.94 in group 2. Significant differences in RFA were found between the groups at 2 weeks (P = 0.04), 4 weeks (P = 0.014), and 6 weeks (P = 0.027) after placement. The study results suggest that the use of PRF may enhance the post-insertion stability of dental implants placed in the posterior maxilla during the healing period.     

Molecular alterations of newly formed mandibular bone caused by zoledronate

Bone quality is defined by structural and material characteristics. Most studies on the mandible have focused on the analysis of structural characteristics, with insufficient investigation of material characteristics. This study tested whether zoledronate affects the material characteristics of newly formed mandibular bone. Thirty-six female Wistar rats were assigned to three groups: sham-ovariectomized rats (SHAM, n = 12), ovariectomized rats (OVX, n = 12), and ovariectomized rats treated with zoledronate (ZOL, n = 12). The left side of the mandibular ramus of all rats was drilled bicortically. Twenty-eight days after surgery, all surviving rats were euthanized and all mandibles were removed. Raman microspectroscopy was performed, and five spectra per specimen of newly formed mandibular bone were analysed. Compared with OVX rats, the mineral/matrix ratio in ZOL rats was significantly increased (5.43 ± 1.88 vs. 7.86 ± 2.05), while crystallinity (0.055 ± 0.002 vs. 0.050 ± 0.002), relative proteoglycan content (0.43 ± 0.10 vs. 0.31 ± 0.05), and collagen structural integrity (1.16 ± 0.21 vs. 0.72 ± 0.06) were significantly decreased. These changes in material characteristics may explain why rats that received zoledronate exhibited peculiar biological phenomena such as bisphosphonate-related osteonecrosis of the jaw.     

Influence of platelet rich fibrin on post-extraction socket healing: A clinical and radiographic study

Aim

The aim of this study was to evaluate clinically and radiographically, extraction socket healing using autologous platelet rich fibrin (PRF).

A comparison of autogenous bone graft combined with deproteinized bovine bone and autogenous bone graft alone for treatment of alveolar cleft

This study assessed the use of composite autogenous bone and deproteinized bovine bone (DBB) for repairing alveolar cleft compared with autogenous bone alone in terms of clinical outcomes and patient morbidity. 30 patients with a mean age of 10.2 ± 1.7 years were randomly divided into two groups. Group I used autogenous cancellous bone graft harvested from the anterior iliac crests by the conventional trapdoor approach. Group II used a composite of DBB and autogenous cancellous bone harvested by a trephine bone collector; the proportion of 1:1 by volume was used. The bone graft quantities of both groups decreased with time. Their average changes were not statistically different over 24 months after grafting. The canines of both groups could spontaneously or orthodontically erupt through the grafting areas. Patients in group II recovered from uncomfortable walking significantly faster than those in group I (p < 0.05) and their duration of hospital stay was significantly shorter than those in group I (p < 0.05). The average operation time, intra-operative blood loss and postoperative pain were less in group II than in group I (p > 0.05).     

Quality assessment of systematic reviews on vertical bone regeneration

The aim of this study was to evaluate and compare the quality of systematic reviews of vertical bone regeneration techniques, using two quality-assessment tools (AMSTAR and ROBIS). An electronic literature search was conducted to identify systematic reviews or meta-analyses that would evaluate at least one of the following outcomes: implant survival, success rates, complications or bone gain after vertical ridge augmentation. Methodological quality assessment was performed by two independent evaluators. Results were compared between reviewers, and reliability measures were calculated using the Holsti’s method^® and Cohen’s kappa. Seventeen systematic reviews were included, of which seven presented meta-analysis. Mean ±95% confidence interval AMSTAR score was 6.35 [4.74;7.97], with higher scores being correlated with a smaller risk of bias (Pearson’s correlation coefficient = ?0.84; P < 0.01). Cohen’s inter-examiner kappa showed substantial agreement for both checklists. From the available evidence, we ascertained that, regardless of the technique used, it is possible to obtain vertical bone gains. Implant success in regenerated areas was similar to implants placed in pristine bone with results equating between 61.5% and 100% with guided bone regeneration being considered the most predictable technique regarding bone stability, while distraction osteogenesis achieved the biggest bone gains with the highest risk of possible complications.     

Immediate function dental implants inserted with less than 30 N·cm of torque in full-arch maxillary rehabilitations using the All-on-4 concept: retrospective study

The aim of this retrospective clinical study was to evaluate the short-term implant success rate and marginal bone loss in full-arch fixed prosthetic maxillary rehabilitations supported by implants in immediate function with the All-on-4 treatment concept placed with insertion torque of <30 N·cm or ≥30 N·cm. This study included 83 patients (69 female, 14 male) with 332 implants placed (120 inserted with <30 N·cm and 212 inserted with ≥30 N·cm) who were treated between January 2010 and March 2013. Outcome measures were implant success and marginal bone loss at 1 year of follow-up. Ten patients (12.0%; 13 implants inserted with <30 N·cm and 27 implants with ≥30 N·cm) were lost to follow-up. The cumulative implant success rate was 97.5% at the patient level, and 98.3% for implants inserted with <30 N·cm and 97.5% for implants inserted with ≥30 N·cm. The mean ± standard deviation marginal bone loss at 1 year was 1.14 ± 0.38 mm for implants inserted with <30 N·cm and 1.39 ± 0.49 mm for implants inserted with ≥30 N·cm (significant difference; P < 0.001, Wilcoxon signed rank test). These results indicate that implants with insertion torques of <30 N·cm may render comparable success rates and marginal bone loss at 1 year compared to implants inserted with insertion torques of ≥30 N·cm.     

Maxillary sinus floor augmentation and dental implant placement using dentin matrix protein-1 gene-modified bone marrow stromal cells mixed with deproteinized boving bone: A comparative study in beagles

ObjectiveThe aim of the study was to evaluate the effects of the combined use of dentin matrix protein-1 (DMP1) gene-modified bone marrow stromal cells (BMSCs) and Bio-Oss^® for maxillary sinus floor augmentation (MSFA) implant placement in dogs.Materials and methodsBMSCs were derived from bone marrow of six beagles and cultured. The cells were transduced with a lentiviral vector overexpressing the DMP1 gene and enhanced green fluorescent protein (EGFP) gene (Lenti-DMP1/EGFP) in test group, and with a lentiviral vector encoding EGFP gene (Lenti-EGFP) in control group. Six dogs received sinus augmentations using the bilateral approach with a simultaneous implant placement at each site respectively. At the same concentration, 2 × 10⁷ cells/ml, one sinus was grafted using a mixture of autologous DMP1/EGFP gene-modified BMSCs and Bio-Oss^® (DMP1 group), and the contralateral sinus was grafted with autologous EGFP gene-modified bMSCs and Bio-Oss^® (EGFP group). After a 3 month healing period, bone regeneration and osseointegration were evaluated using histologic and histomorphometric methods.ResultsThe bone-implant contact (BIC) and the bone area fraction in the DMP1 group (BIC: 34.67% ± 8.23%, bone area fraction: 35.16% ± 3.32%) were significantly greater compared with the EGFP group (BIC: 26.06% ± 5.16%, bone area fraction: 20.74% ± 1.63%) (P < 0.05). No significant difference between the residual bone substitute material volume (BSMV) in the DMP1 group (35.86 ± 7.35) and the EGFP group (32.16 ± 9.16) was found in our study (P > 0.05).ConclusionBMSCs modified with the DMP1 gene can be used as an adjunct to Bio-Oss^® to enhance new bone formation and the osseointegration of dental implants in MSFA of dogs.     

Bone regeneration with BMP-2 and hydroxyapatite in critical-size calvarial defects in rats

BackgroundThis study describes the effect of bone formation by BMP-2 (bone morphogenetic protein-2), a bone formation inducer, with or without hydroxyapatite (HAP) application to critical-size defects in rat calvarial bone.Material and methodsTwenty male Wistar rats were divided into four groups of 5 animals each: control, HAP, BMP, and mixed BMP/HAP. A Critical-size defect of 4 mm was made using a trephine in the calvarial bone and, after that, BMP and/or HAP was applied to the defect according to the grouping. Defects were evaluated radiographically and histologically using ImageJ color analyzer software at 4 weeks postoperatively.ResultsThe histological data were more precise than the radiologic data due to the white color of the porous-type HAP material. The highest radiopacity was noted in the mixed BMP/HAP group (162.07 ± 9.06), followed by the HAP group (133.15 ± 21.8), then the BMP group (100.79 ± 8.27), and, lastly, the control group (54.45 ± 8.39). After subtracting the white background and using ImageJ for histological analysis, the highest rate of osteochondrogenesis was in the mixed BMP/HAP group (85.29% ± 8.21), and then the BMP group (77.34% ± 7.39), followed by the HAP group (59.82% ± 11.23), and, lastly, the control group (40.27% ± 7.44). Differences in the values between groups were then analyzed using confidence intervals (CI) of 95 and 99%.ConclusionWithin 4 weeks, the mixed BMP/HAP group showed the highest level of bone induction, especially compared to the BMP group, but this was non-significant; even with a 95% CI, the result was negative. This reveals that BMP alone can be applied, with a final result the same as that seen in the mixed BMP/HAP group. BMP and HAP, both being osteoinducting agents, even though they differ from a material classification point of view, have a positive effect on osteogenesis.     

Effect of curcumin on bone tissue in the diabetic rat: repair of peri-implant and critical-sized defects

This study determined the effect of curcumin on bone healing in animals with diabetes mellitus (DM). One hundred rats were divided into five groups: DM + PLAC, DM + CURC, DM + INS, DM + CURC + INS, and non-DM (CURC, curcumin; PLAC, placebo; INS, insulin). Critical calvarial defects were created and titanium implants were inserted into the tibiae. Calvarial defects were analyzed histometrically, and BMP-2, OPN, OPG, RANKL, Runx2, Osx, β-catenin, Lrp-5, and Dkk1 mRNA levels were quantified by PCR. The implants were removed for a torque evaluation, the peri-implant tissue was collected for mRNA quantification of the same bone-related markers, and the tibiae were submitted to micro-computed tomography. The DM + CURC + INS and non-DM groups exhibited greater closure of the calvaria when compared to the DM + PLAC group (P < 0.05). Increased retention of implants was observed in the DM + CURC, DM + CURC + INS, and non-DM groups when compared to the DM + PLAC group (P < 0.05). CURC improved bone volume and increased bone–implant contact when compared to DM + PLAC (P < 0.05). In calvarial samples, CURC favourably modulated RANKL/OPG and Dkk1 and improved β-catenin levels when compared to DM + PLAC (P < 0.05). In peri-implant samples, Dkk1 and RANKL/OPG were down-regulated and BMP-2 up-regulated by CURC when compared to DM + PLAC (P < 0.05). CURC reverses the harmful effects of DM in bone healing, contributing to the modulation of bone-related markers.     

The local administration of parathyroid hormone encourages the healing of bone defects in the rat calvaria: Micro-computed tomography,histological and histomorphometric evaluation

ObjectiveTo evaluate the effect of a single-dose local administration of PTH on bone healing in rat calvarial bone defects by means of micro-computed tomography, histological and histomorphometric analysis.DesignCritical-size cranial osteotomy defects were created in 42 male rats. The animals were randomly divided into 3 groups. In the C Group, the bone defect was only filled with a blood clot. In the S Group, it was filled with a collagen sponge and covered with bovine cortical membrane. In the PTH Group, the defect was filled with a collagen sponge soaked with PTH and covered with bovine cortical membrane. The groups were further split in two for euthanasia 15 and 60 days post-surgery. Data was statistically analyzed with t-tests for independent samples or the nonparametric Mann-Whitney test when applicable. Intragroup comparisons were analyzed with paired t-tests (p < 0.05).ResultsMicro-CT analysis results did not demonstrate statistically significant intergroup differences. At 15 days post-surgery, the histomorphometric analysis showed that the PTH Group exhibited a significantly higher percentage of bone formation compared with the S Group. At 60 days post-surgery, a higher percentage of new bone was observed in the PTH group.ConclusionThe results suggest that the local administration of PTH encouraged the bone healing in critical-size calvarial defects in rats.     

Influence of low-level laser therapy on the healing process of autogenous bone block grafts in the jaws of systemically nicotine-modified rats: A histomorphometric study

ObjectiveTo analyze the influence of low-level laser therapy (LLLT) on the bone healing process of autogenous bone block grafts installed in nicotine systemically modified rats.MethodsSeventy-two rats (Wistar) were randomly assigned into 4 groups (n = 18). SS-BG: saline application + bone graft. SS-BG/LLLT: saline application + bone graft + LLLT. NIC-BG: nicotine application + bone graft. NIC-BG/LLLT: nicotine application + bone graft + LLLT. After 30 days of application of solutions, all animals received autogenous bone block graft in the jaw, with the donation from the parietal bone’s calvarial area. Treatment with LLLT was in bed-graft interface, after accommodation of the graft. The animals in each group were sacrificed at 7, 14, and 28 days after graft surgery.ResultsThe histologic analyses of NIC-BG group depicted a delay of osteogenic activity in the recipient bed-graft interface and the irradiation of tissue with LLLT provided better bone healing. The histometric analysis revealed that SS-BG/LLLT and NIC-BG/LLLT groups showed increased bone formation compared to BG-SS and NIC-BG groups, after 14 days (SS-BG 24.94% ± 13.06% versus SS-BG/LLLT 27.53% ± 19.07% and NIC-BG 14.27% ± 2.22% versus NIC-BG/LLLT 24.37% ± 11.93%) and 28 days (SS-BG 50.31% ± 2.69% versus SS-BG/LLLT 58 19% ± 12.32% and NIC-BG 36.89% ± 8.40% versus NIC-BG/LLLT 45.81% ± 6.03%).ConclusionNicotine harms bone formation in the bed-graft interface and LLLT action can mitigate this.     

Impact of surface contamination of implants with saliva during placement in augmented bone defects in sheep calvaria

Our aim was to try and find out whether contamination with saliva during insertion of dental implants affects osseointegration in bone that has been augmented with different grafts. Six bony defects were created in each of the calvaria of six sheep, and then augmented with three different materials (autogenous bone, bovine bone, and resorbable biphasic ceramic bone substitute) After five weeks of healing, three implants contaminated with saliva (contaminated group) and three not contaminated (uncontaminated group) were placed in the centre of the augmented areas. For histomorphometric analysis, bone implant contact, bone area fraction occupancy, bone and material area, and bony area were measured after a healing period of five weeks. There was a significant difference between the contaminated and uncontaminated groups (p = 0.036) for bone implant contact only in the augmented areas, but there were no significant differences in bone area fraction occupancy, bone and material area, and bony area. We conclude that contamination with saliva during placement of dental implants can significantly compromise bone implant contact in augmented areas, but had no significant effect on the formation of bone in areas more distant from the surface of the implant. We suggest that salivary contamination should be avoided during placement of dental implants in augmented areas.     

Proportion of deproteinized bovine bone and autogenous bone affects bone formation in the treatment of calvarial defects in rabbits

This study assessed new bone formation generated using three different proportions of autogenous bone (AB) and deproteinized bovine bone (DBB). Thirty bicortical skull defects were prepared in 15 rabbits, divided into 3 groups: Group 1, critical size defect (CSD) versus AB as controls; Group 2, DBB versus a composite of AB and DBB using a proportion of 1:1; and Group 3, a composite of AB and DBB using a proportion of 1:2 versus a proportion of 1:4. After 8 weeks, radiographic evaluation was assessed using densitometry and new bone formation by histomorphometry. The mean optical density of the CSD (0.108 ± 0.238) and AB (0.352 ± 0.161) groups differed significantly from the DBB group (1.044 ± 0.093) and the groups using a proportion of 1:1 (0.905 ± 0.078), 1:2 (0.865 ± 0.294) and 1:4 (0.867 ± 0.304). Histomorphometry revealed a higher percentage of new bone in the AB group (30.223 ± 16.722) than in the groups using proportions of 1:2 (22.639 ± 5.659), 1:1 (20.929 ± 6.169), 1:4 (9.621 ± 2.400), DBB (14.441 ± 2.742) and CSD (10.645 ± 8.868), respectively. The 1:2 group had significantly higher bone content than the 1:4 group. The proportions of 1:1 and 1:2 resulted in greater bone formation than the proportion of 1:4, DBB and CSD.     

Mandibular alveolar bone volume in patients with different vertical facial dimensions

Objective

To evaluate if there is any difference in alveolar bone surface area in patients with high vertical facial dimension (long face), average vertical facial dimension (average face), and low vertical facial dimension (square short face).

Influence of tumour necrosis factor alpha on epithelial–mesenchymal transition of oral cancer cells in co-culture with mesenchymal stromal cells

Tumour progression in head and neck squamous cell carcinoma (HNSCC) is influenced by the surrounding stroma and inflammatory cytokines such as tumour necrosis factor alpha (TNF-α). The aim of this study was to test the hypothesis that TNF-α modulates the interactions of HNSCC cell line PCI-13 and bone marrow mesenchymal stromal cells (BMSCs) and influences markers of epithelial–mesenchymal transition (EMT). Following induction with TNF-α, mono- and co-cultures of BMSCs and the established HNSCC cell line PCI-13 were analyzed; protein expression of E-cadherin and vimentin and qRT-PCR expression of Snail, Twist, MMP14, vimentin, E-cadherin, and β-catenin were examined, and changes in cellular AKT signalling were analyzed. TNF-α induced a significant decrease in E-cadherin (64.5 ± 6.0%, P = 0.002) and vimentin (10.4 ± 3.5%, P = 0.04) protein expression in co-cultured PCI-13, while qRT-PCR showed a significant increase in β-catenin (BMSCs P < 0.0001; PCI-13 P = 0.0005) and Snail (BMSCs P = 0.009; PCI-13 P = 0.01). TNF-α also resulted in a down-regulation of AKT downstream targets S6 (38.7 ± 20.9%, P = 0.01), p70S6 (16.7 ± 12%, P = 0.05), RSK1 (23.6 ± 28.8%, P = 0.02), and mTOR (27.4 ± 17.5%, P = 0.004) in BMSC co-cultures. In summary, while reducing the expression of vimentin and AKT-signalling in PCI-13 and BMSC, respectively, TNF-α introduced an inflammatory-driven tumour–stroma transition, marked by an increased expression of markers of EMT.     

Costochondral grafting for paediatric temporomandibular joint reconstruction: 10-year outcomes in 55 cases

Costochondral grafting (CCG) can be used for the reconstruction of ankylotic, hypoplastic, and resected temporomandibular joint (TMJ) defects. CCGs have previously been considered the gold standard in children due to their growth potential and autogenous origin, but the disadvantages are unpredictable growth and joint ankylosis. This was a retrospective study of all children who received CCGs for TMJ reconstruction from 1985 to 2004, to allow a 10-year follow-up. Fifty-five patients were included in this study, with 74 grafts being placed; their mean age was 7.9 ± 4.2 years. Infection-related ankylosis (18.2%) and craniofacial microsomia (16.4%) were the most common diagnoses. Overall, 58.2% of patients suffered one or more complications over the follow-up period, with ankylosis (32.7%) and overgrowth (16.4%) being most common. There was a significant correlation between those with infection-related ankylosis and subsequent complications (χ² = 8.8, df = 1, P < 0.005), while ankylotic patients in general exhibited greater overall complication rates (χ² = 9.0, df = 1, P < 0.005). Patients with congenital TMJ defects were more likely to be complication-free than those with acquired defects (χ² = 4.0, df = 1, P < 0.05). Caution is advised when placing CCGs in paediatric patients with ankylosed TMJs, especially those with infection-related ankylosis.