Peri-implant marginal bone changes with implant-supported metal-ceramic or monolithic zirconia single crowns: A retrospective clinical study of 1 to 5 years.

STATEMENT OF PROBLEM: Monolithic zirconia has excellent mechanical and biologic properties. However, evidence of the clinical properties of implant-supported monolithic zirconia prostheses is limited. PURPOSE: The purpose of this retrospective clinical study was to compare the peri-implant marginal bone changes of metal-ceramic and monolithic zirconia single crowns in the posterior region after prosthetic loading. MATERIAL AND METHODS: A total of 224 participants treated with 327 implants restored with either metal-ceramic or monolithic zirconia single crowns in the posterior region between 2012 and 2016 were included in this study. Clinical outcomes, including the plaque index, peri-implant probing depth, and bleeding on probing, were recorded, and the marginal bone level was recorded by using the panoramic radiographs obtained at implant placement, second-stage surgery, and the most recent follow-up visit. The included parameters were analyzed with the nonparametric Mann-Whitney tests (α=.05). RESULTS: The mean follow-up time was 30.4 months, and the cumulative survival rate of implants was 100% and that of the prostheses was 99.1%. The plaque index was 0.46 in the metal-ceramic group, which was significantly higher (P<.05) than 0.37 in the monolithic zirconia group. However, no significant differences (P>.05) were observed in peri-implant probing depth and bleeding on probing between the 2 groups. The marginal bone level at implant placement, second-stage surgery, and the most recent follow-up visit was above the implant platform in both the metal-ceramic and monolithic zirconia groups. The marginal bone changes of the metal-ceramic group was 0.31 mm in the healing period and 0.38 mm in the prosthetic loading period, while in the monolithic zirconia group, it was 0.25 mm in the healing period and 0.43 mm in the prosthetic loading period; no significant differences (P>.05) were observed between the 2 groups. CONCLUSIONS: The peri-implant marginal bone level change was comparable after prosthetic loading for metal-ceramic and monolithic zirconia single crowns, although monolithic zirconia was associated with reduced plaque.

Clinical evaluation of xenogeneic collagen matrix versus free gingival grafts for keratinized mucosa augmentation around dental implants: A randomized controlled clinical trial.

AIM: To evaluate the outcomes of an apically repositioned flap (ARF) plus xenogeneic collagen matrix (XCM) in augmenting keratinized mucosa width (KMW) around dental implants when compared with ARF plus free gingival grafts (FGG). MATERIALS AND METHODS: Twenty-six participants with at least one site with KMW ≤2 mm were randomized into FGG or XCM group. Clinical examinations were performed at baseline and at 2 and 6 months after surgery, including KMW, keratinized mucosa thickness, gingival index (GI), and probing depth (PD). Post-operative pain and patient satisfaction were also evaluated. RESULTS: At 6 months, FGG attained a greater increase of KMW and thicker mucosa than XCM (4.1 ± 1.6 mm vs. 1.8 ± 1.0 mm, p < .001; 1.7 ± 0.6 mm vs. 1.2 ± 0.3 mm, p < .01). Regarding GI, PD, post-operative pain, aesthetic outcomes, and patient satisfaction, no significant difference could be detected. Moreover, the operation time of XCM group was shorter (60 ± 9 min vs. 39 ± 8 min, p < .001). CONCLUSIONS: FGG could result in greater increase of KMW than XCM, though both could increase KMW, maintain peri-implant health, and attain comparable aesthetic outcomes. The use of XCM was associated with reduced operation time.

Gingival Plasma Cell Granuloma: A case Report of Multiple Lesions.

BACKGROUND: Plasma cell granuloma (PCG) is a rare benign pseudotumorous proliferation of unclear etiology that is mainly situated in the lungs. Gingival PCG is an even more peculiar lesion that usually occurs in middle-aged or elderly individuals and clinically manifests as a solitary entity. CASE REPORT: A 15-year-old male with no underlying medical conditions presented with multiple gingival masses in the right maxilla, which were initially thought to be epulis. The lesions were resected completely and the excisional biopsies sent for histological examination. Immunohistochemical (IHC) stain revealed dense polyclonal plasma cell infiltration with positive expression of both kappa and lambda light chains, confirming a diagnosis of gingival PCG. Subsequently, the affected gingiva healed uneventfully, with no sign of recurrence over 2 years of follow-up. CONCLUSIONS: The present report depicts an extremely unusual case of gingival PCG occurring in a juvenile with multiple lesions, which is worth attention in clinical pediatric dentistry. Excisional-biopsy and histological investigations are imperative for a confirmative diagnosis and to exclude potential aggressive conditions. Complete resection of lesions seems to be a valid treatment, while long-term clinical follow-up is still needed.

Positive effect of strontium-oxide layer on the osseointegration of moderately rough titanium surface in non-osteoporotic rabbits.

OBJECTIVES: To evaluate the effect of strontium-oxide layer on new bone formation and osseointegration of sandblasted large-grit double-acid-etched (SLA) implant. MATERIAL AND METHODS: Strontium-oxide layer on the SLA surface was produced by hydrothermal treatment using a Sr-containing solution. The surface topographies, roughness, hardness values, chemical elements and ionic release of SLA and the strontium-containing SLA (Sr-SLA) surface were measured by special instruments separately. Sixty-four SLA and Sr-SLA implants were inserted into the proximal tibiae and femoral condyles of sixteen non-osteoporotic New Zealand white rabbits. The biological effects were evaluated by removal torque (RTQ) testing and histomorphometric analysis after 3 and 6 weeks of implantation. RESULTS: The surface characteristics showed Sr-SLA surfaces with dotted nanostructures can release appropriate amount of strontium ions into surrounding tissue till 14 days. In vivo, the Sr-SLA implants presented significantly higher RTQ than SLA implants at 3 and 6 weeks (P < 0.05). The Sr-SLA implants presented higher bone-to-implant contact (BIC) than SLA implants in cortical bone at 3 and 6 weeks (P < 0.05). The bone area was slightly higher for the Sr-SLA implants at 3 and 6 weeks (P > 0.05). CONCLUSIONS: The strontium-oxide layer on the SLA surface has the potential to improve implant osseointegration in non-osteoporotic rabbits.

Long-term outcomes of osteotome sinus floor elevation without bone grafts: a clinical retrospective study of 4-9 years.

OBJECTIVE: To evaluate the long-term clinical and radiographic outcomes of dental implant placed using osteotome sinus floor elevation (OSFE) without bone grafts, and to analyze the potential influence factors of implant survival and endo-sinus bone remodeling. MATERIAL AND METHODS: A retrospective study design was adopted. The clinical and radiographic data of 96 implants in 80 patients were collected after 4-9 (mean 5.40) years follow-up. Implant failures, peri-implant marginal bone loss (MBL), and endo-sinus bone remodeling on the radiographs were evaluated. A life-table analysis was used to assess the implant survival. Statistical models were established to investigate the potential influence factors of implant survival and endo-sinus bone gain (ESBG). RESULTS: In total, nine implants in seven patients failed, giving the 9-year cumulative survival rates of 90.6% and 91.3% for implant-based analysis and patient-based analysis, respectively. The mean MBL between implant installation and the 4- and 9-year follow-up visit was 0.46 ± 0.88 and 0.50 ± 1.69 mm, respectively. The average ESBG on radiographs was 2.95 ± 1.25 and 2.16 ± 1.13 mm at the 4- and 9-year follow-up. The final ESBG was found to be positively correlated to implant protrusion length after surgery without any other factors related. The implant survival rate was significantly lower in severe atrophic site (residual bone height <5 mm). CONCLUSION: Osteotome sinus floor elevation without bone grafts is a predictable treatment modality in the long run. But it should be used with caution when the initial bone height of the edentulous site is lower than 5 mm. The final endo-sinus bone height was found to be positively correlated to implant protrusion length measured on radiographs immediately after implant installation.

Effects of magnesium-substituted nanohydroxyapatite coating on implant osseointegration.

OBJECTIVE: The objective of this study was to compare magnesium-substituted and pure hydroxyapatite coatings on the promotion of osteogenesis in vitro and on the osseointegration in vivo. METHODS: Electrochemically deposited pure hydroxyapatite (EDHA) or electrochemically deposited magnesium-substituted hydroxyapatite (EDMHA) coatings were formed on the surface of pure titanium disks or implants. MC3T3-E1 preosteoblasts were cultured in the EDHA and EDMHA coated disks, and cell growth, alkaline phosphatase (ALP) activity, and osteocalcin secretion were measured at various time points. For studies on osseointegration, 30 roughened implants coated either with EDHA or EDMHA (n = 15 for each coating) were implanted in the femurs of 15 NZW rabbits. After 2, 4, and 8 weeks, femurs were retrieved and prepared for histomorphometric evaluation (n = 5 for each coating at each time point). RESULTS: MC3T3-E1 cells cultured on EDMHA coated disks showed increased cell number, ALP, and osteocalcin secretion compared with the EDHA coated disks at all time points (P < 0.05 for all). Histologic observation of the coated implants showed woven bone in direct contact with both implant surfaces after 2 weeks and mature bone after 8 weeks. While there were no differences in the amount of bone between the threads at any time point, the percentage of implant in direct contact with bone (bone implant contact) was slightly higher along the EDMHA coated implants at 2 weeks (P = 0.086), although this difference was no longer seen at 4 and 8 weeks. CONCLUSION: Mg-substituted HA coated surfaces promote osteogenic differentiation of preosteoblasts in vitro and may improve implant osseointegration during the early stages of bone healing compared with pure EDHA coated surfaces.

Bone response to the multilayer BMP-2 gene coated porous titanium implant surface.

OBJECTIVES: Evaluate hBMP-2 expression following gene delivery from plasmid multilayers formed on sandblasted titanium in vitro and bone formation around similarly prepared implant surfaces in vivo. MATERIALS AND METHODS: Multilayers of cationic lipid/rhBMP-2 plasmid DNA complex (LDc) and anionic hyaluronic acid (HA) was assembled on sandblasted-dual acid etched pure titanium disks or implant surfaces using layer-by-layer (LBL) assembly. Gene delivery and hBMP-2 expression in cells exposed to the LDc multilayers was measured in vitro. To determine the effect of BMP delivery from such multilyaers in vivo, roughened implants coated with BMP-2 LDc multilayers or uncoated control implants (n = 15 for both) were implanted in the femurs of NZW rabbits. After 2, 4, 8 weeks, femurs were retrieved and prepared for histomorphometric evaluation (n = 5 rabbits per time point). RESULTS: MC3T3-E1 cells cultured directly on the BMP-2 LDc coated titanium disks showed EGFP and hBMP-2 expression after 48 h in culture. Increased gene delivery occurred by increasing the number of assembly layers when cells were cultured for 48 h. Cells cultured on LDc coated surfaces had significantly higher cell viability than control cells cultured on uncoated porous titanium surfaces. Histologic observation of the implants showed that after 4 weeks healing, the bone to implant contact (BIC) on the LDc coated surface was much lower than that on the control surface, but didn't reach significant. In contrast, the percentage of bone within the implant's threads was significantly higher than the control group (P = 0.047). CONCLUSION: The BMP-2 gene coated sandblasted dual acid etched titanium implants slightly accelerated early bone formation around implants.

[Measurement of facial bone wall thickness of maxillary anterior teeth and premolars on cone beam computed tomography images].

OBJECTIVE: To measure the thickness of facial bone wall of maxillary anterior teeth and premolars based on cone beam computed tomography (CBCT) images. METHODS: CBCT images from 118 patients were collected from the Affiliated Stomatology Hospital of Zhejiang University. The thickness perpendicular to the long axis of facial bone wall was measured at two locations: 4 mm apical to the cementoenamel junction (point 1) and the middle of the root (point 2). RESULTS: The thickness of the facial bone walls of central incisors, lateral incisors and canines ranged from 0.5 to 1.5 mm. A thin facial bone wall (<1.0 mm) was quite frequent in central incisors (44.1% at point 1, 56.8% at point 2), lateral incisors (65.2% at point 1, 89.8% at point 2) and canines (45.8% at point 1, 61.0% at point 2). In contrast, the majority of examined first premolars (77.1% at point 1, 68.7% at point 2) and second premolars (94.1% at point 1, 94.1% at point 2) exhibited a thick facial bone wall (>1.0 mm). CONCLUSION: A thin facial bone wall of teeth in the anterior maxilla is common. Radiographic analysis of facial bone wall using CBCT is recommended for selection of appropriate treatment approach.

The Effect of Initial Biologic Width on Marginal Bone Loss: A Retrospective Study.

PURPOSE: To evaluate the short-term effect of dental implant placement, mucosa thickness, and their combined effects (initial biologic width) on marginal bone loss. MATERIALS AND METHODS: This was a retrospective study on patients who received implant surgery in the posterior region without bone augmentation surgery between 2012 and 2016, and implants had been loaded for more than 12 months. Each patient received radiographic examination before and after implant surgery, before the stage-two surgery, and during the 1- to 5-year follow-up. The thickness of mucosa, depth of dental implant placement, and crestal bone loss were evaluated on digital radiographs. The interaction was discussed by defining the combination of initial mucosal thickness and implantation depth as the initial biologic width. The implants were divided into four study groups based on the quartile of the initial biologic width. RESULTS: This study included 266 patients (94 male and 172 female, 22 to 85 years of age, mean age: 51.43 years), with 413 dental implants placed including 239 Straumann implants and 174 Ankylos implants. The average follow-up was 21.50 months. After 1 to 5 years, the median crestal bone loss around implants was 0.35 mm (0.30 mm for Straumann BL and 0.40 mm for Ankylos). The implants were divided into four groups: group A (≤ 2.85 mm), group B (2.85 to 3.40 mm), group C (3.40 to 3.97 mm), and group D (> 3.97 mm). Group B showed significantly less crestal bone loss than group A (0.38 mm vs 0.25 mm; P < .05) and group C (0.25 mm vs 0.40 mm; P < .05) during the follow-up. Significantly more crestal bone loss around implants was observed in the thin mucosa group than in the thick mucosa group (0.50 mm vs 0.30 mm; P < .001), while implants placed beneath the bone level displayed a significantly higher amount of marginal bone loss than implants placed even with the bone crest (0.50 mm vs 0.10 mm; P < .001). CONCLUSION: The initial biologic width has an effect on crestal bone loss. When the initial biologic width was between 2.85 and 3.40 mm, the marginal bone loss was lowest. Based on radiographic evaluation, implants placed in thick gingiva and even with the bone level showed less alveolar marginal bone loss compared with implants placed in thin gingiva and below the crestal bone level.

Mechanical and histomorphometric evaluations of rough titanium implants treated with hydrofluoric acid/nitric acid solution in rabbit tibia.

PURPOSE: The aim of this study was to investigate the bone response to rough titanium implants treated with hydrofluoric acid/nitric acid (HF/HNO3) solution. MATERIALS AND METHODS: Implants were treated with HF/HNO3 solution (test implants) or without HF/HNO3 solution (control implants). Forty-five test and 45 control implants were inserted into both tibias of 15 rabbits. After 2, 4, and 8 weeks in situ, tibias were retrieved and prepared for removal torque testing and histomorphometric evaluation. The removed implants were prepared and observed with an electron microscope. RESULTS: Mechanical tests showed that mean removal torque values for the test implants were higher than those of the control implants after 8 weeks (33.1 Ncm versus 25.7 Ncm, P = .012). Histomorphometric analysis showed that the bone area in the threads of the cortical bone region was significantly higher for test implants (81.99% and 86.38%) than for control implants (75.33% and 81.62%) after 4 and 8 weeks of healing, respectively. The implant-bone contact rate in the cortical region was higher for test implants than for control implants after 8 weeks in situ (79.56% versus 68.45%, P = .003). CONCLUSIONS: The treatment with HF/HNO3 solution promotes bone formation and osseointegration after 4 and 8 weeks of bone healing in the rabbit tibia model.

Responses of Sinus Membrane and Antral Pseudocyst Following Lateral Window Sinus Augmentation with Bone Grafting: A Retrospective Study.

PURPOSE: To investigate the influence of lateral window sinus augmentation on sinus physiology, including sinus membrane thickness and the outcome of antral pseudocysts. MATERIALS AND METHODS: This retrospective study was performed by reviewing all lateral window sinus augmentation procedures, which were done between the years 2013 and 2015. Each enrolled patient had CBCT images preoperatively (T0), immediately postoperatively (T1), and 6 months postoperatively (T2). The sinus membrane thickness, pseudocyst dimensions, and intraoperative perforation were evaluated. Patient-related factors such as age and sex that could influence the mucosal properties were also analyzed. RESULTS: Based on established inclusion criteria, 306 patients with 320 sinuses were included in this study. The overall mean thickness of the sinus membrane (T0) was 1.30 ± 1.08 mm, and membrane thickening (> 2 mm) was observed in 22.19% of the sinuses. Preexisting pseudocysts were identified in 24 sinuses (7.50%), most of which remained unchanged or disappeared after 6 months. The intraoperative membrane perforation rate was lowest (1.96%) when the membrane thickness was 1.0 to 1.5 mm, and the perforation rate was increased in patients with thickened (> 2 mm) or thinned (≤ 1 mm) membrane. Membranes swelled immediately after operation (T1 vs T0, P < .01) and gradually recovered at 6 months. No significant change in membrane thickness was shown after the sinus augmentation procedure in the perforation group and pseudocyst group. The mean thickness of the sinus membrane at T0 and T1 was significantly higher for male subjects (P < .01). CONCLUSION: Lateral window sinus augmentation has little or no impact on sinus membrane thickness and antral pseudocysts after a 6-month healing period, except for a transient mild membrane swelling. Thickened and thinned membrane were risk factors for intraoperative perforation. Small-sized perforation and pseudocysts might not contraindicate sinus augmentation from the standpoint of the surgical impact on the sinus membrane.

Effects of strontium-incorporated micro/nano rough titanium surfaces on osseointegration via modulating polarization of macrophages.

Macrophages perform multiple functions in both inflammation and wound healing, and are one of the fore front cells during implant osseointegration that influence subsequent process. Essential trace element modification may effectively modulate titanium implant surface biological properties. In this work, strontium (Sr) incorporated micro/nano rough titanium surfaces (Sr-SLA) was fabricated by hydrothermal treatment, and immunoreaction of macrophages was further investigated. In vitro results revealed that Sr doping inhibited inflammatory response of macrophages, further attenuated the inhibitory effect on following bone marrow derived cells (BMSCs) osteogenic differentiation. The regulation of macrophages by Sr-SLA likely involved ERK signaling pathway. Consistently, the in vivo study showed that compared with titanium surface sand-blasted with large grit and double acid-etched (SLA) implants, Sr-SLA implants could enhance new bone formation accompanied with more alternatively activated M2 macrophages infiltration and less classically activated M1 macrophages infiltration. These results reveal the immunomodulatory ability of Sr-SLA of adjusting the functional status of macrophages through inhibiting M1 polarization while promoting M2 polarization.

In vivo comparison of bone formation on titanium implant surfaces coated with biomimetically deposited calcium phosphate or electrochemically deposited hydroxyapatite.

PURPOSE: The purpose of this study was to investigate and compare bone formation on titanium implant surfaces coated with biomimetically deposited calcium phosphate (BDCaP) or electrochemically deposited hydroxyapatite (EDHA). MATERIALS AND METHODS: The implants were separated into three groups: a control group, a BDCaP group, and an EDHA group. Surface analysis was performed by field-emission scanning electron microscopy, x-ray diffractometry, and Fourier transform infrared spectroscopy. Implants were inserted in a randomized arrangement into rabbit tibiae. After 2, 4, and 8 weeks, the tibiae were retrieved and prepared for histomorphometric evaluation. RESULTS: Field-emission scanning electron microscopy showed that the BDCaP crystals were flakelike and the EDHA crystals were rodlike with a hexagonal cross section. X-ray diffractometric patterns and Fourier transform infrared spectroscopy spectra showed that the BDCaP coating consisted of HA and octacalcium phosphate, whereas the EDHA coating consisted of HA. Histologic observation showed that new bone on the EDHA-coated implant became mature after 4 weeks, while new bone on the control and BDCaP-coated implants was mature after 8 weeks. The EDHA implant showed significantly greater BIC and bone area compared to the control and BDCaP implants during 4 to 8 weeks. The BDCaP coating failed to show increased bone formation during the test period. CONCLUSION: The present EDHA coating has good bone formation properties, while the BDCaP coating has weaker bone formation properties.

Cell response of titanium implant with a roughened surface containing titanium hydride: an in vitro study.

PURPOSE: The purpose of this study was to investigate the effect of surface chemistry of a sandblasted and acid-etched implant (with and without titanium hydride [TiH(2)]) on cell attachment, proliferation, and differentiation of preosteoblasts (MC3T3-E1). MATERIALS AND METHODS: Sandblasted and dual acid-etched titanium discs comprised the test group, whereas sandblasted, acid-etched, and heat-treated discs comprised the control group. Both groups' discs were sent for surface characterization. MC3T3-E1 cells were cultured on these 2 groups' discs, and then cell attachment, cell proliferation, and cell differentiation were analyzed. RESULTS: Scanning electron microscope analysis showed that the titanium discs in the 2 groups shared the same surface topography; however, x-ray diffraction examination showed that the TiH(2) diffractions only appeared in the test group. Cell attachment and cell proliferation were much better in the test group than in the control group at all time points investigated (P < .05). The expressions of alkaline phosphatase and osteocalcin were significantly higher in the test group than in the control group for both protein and transcription level at every time point (P < .05 or P < .01). CONCLUSIONS: These results suggested that surface chemistry played a significant role in cell response to the sandblasted and acid-etched surface and the presence of TiH(2) might promote the attachment, proliferation, and differentiation of preosteoblasts.

Biomechanical comparison of biomimetically and electrochemically deposited hydroxyapatite-coated porous titanium implants.

PURPOSE: The purpose of this study was to investigate the effects of biomimetically and electrochemically deposited hydroxyapatite on the fixation of an implant with bone tissue. MATERIALS AND METHODS: Implants were separated into 3 groups: roughened group, biomimetically deposited calcium-phosphorus (BDCaP) group, and electrochemically deposited hydroxyapatite (EDHA) group. We randomly inserted 90 implants into the femurs of 45 rabbits. After 2, 4, and 8 weeks, the femurs were retrieved and prepared for removal torque tests (RTQs) and field-emission scanning electron microscopy observation. RESULTS: During the test period, the EDHA group showed significantly greater RTQ values than did the roughened group and BDCaP group. The BDCaP group failed to increase the RTQ values compared with the roughened group. Field-emission scanning electron microscopy observation showed that the amount of attached bone tissue on the EDHA-coated implant surface was more than that on the roughened and BDCaP-coated implant surfaces during the test period. CONCLUSION: The electrochemical hydroxyapatite coating contributes to the fixation between bone and implant compared with the roughened surface, whereas the biomimetic calcium-phosphorus coating has little effect on the fixation.

[Reliability and validity of the Chinese version of the 5-item oral health impact profile].

OBJECTIVE: To evaluate the reliability and validity of the Chinese version of the 5-item oral health impact profile (OHIP-5). METHODS: According to the international guidelines, the Chinese version of the OHIP-5 was produced. It was applied to patients who visit our clinic. The reliability of the scale was evaluated by internal consistency reliability and test-retest reliability. In addition, the validity of the scale was evaluated by construct validity and convergent validity. RESULTS: A total of 556 patients were enrolled in the study. The Cronbach's alpha and the intraclass correlation coefficient values (ICC) of the Chinese version of the OHIP-5 were 0.868, 0.831, respectively. The results of the confirmatory factor analysis (CFA) showed that the one-factor model provided an acceptable fit to the data. The fit indices were: the chi-square fit statistics/degree of freedom (χ²/df)=2.419, the goodness-of-fit index (GFI)=0.995, the adjusted goodness of fit index (AGFI)= 0.960, the normed fit index (NFI)=0.996, the incremental fit index (IFI)=0.997, the Tucker-Lewis index (TLI)= 0.985, the comparative fit index (CFI)=0.997, and the root mean square error of approximation (RMSEA)=0.070. For the convergent validity of the scale, the Spearman's rank correlation coefficient was 0.674. CONCLUSIONS: The Chinese version of OHIP-5 had a good reliability and validity by rigorous psychometric properties. Overall, it can be further promoted in clinical research and epidemiological investigations.

Biomechanical and Morphometric Evaluation of a Strontium-Incorporated Implant and Four Commercially Available Implants: A Study in Rabbits.

PURPOSE: Strontium has shown a positive effect on osseointegration in experiments. This study compared surface characterization and osseointegration of a strontium-incorporated implant with four commercial implants with different surface treatments. MATERIALS AND METHODS: A strontium-oxide layer was created by hydrothermal treatment on the surface of the implant (SLA-Sr). Surface characterizations were observed using a scanning electron microscope, three-dimensional (3D) optical microscope, and x-ray energy-dispersive spectrometry. Implants of different surface treatments including resorbable blasting media (RBM), sandblasting with large grit and acid etching (SLA-1, SLA-2), sandblasting and thermal acid etching (STA), and SLA-Sr were implanted into the proximal tibiae and femoral condyles of rabbits. Biologic effects were evaluated by removal torque testing and histomorphometric analysis after 3, 6, and 12 weeks of implantation. RESULTS: Nanostructures were observed on the surface of SLA-Sr and STA. Calcium (Ca) was detected on the surface of RBM. Sr was detected on the surface of SLA-Sr. SLA-1 and STA had greater surface roughness than SLA-2, SLA-Sr, and RBM (P < .05). In vivo, SLA-Sr achieved better removal torque value (RTV) than that of RBM and SLA-2 at 3 weeks (P < .05), as well as increased bone area ratio (BA%) in cortical bone compared with RBM at 3 weeks (P < .05). STA showed higher bone-to-implant contact ratio (BIC%) in cortical bone than RBM at 3 and 6 weeks (P < .05). Compared with RBM, SLA-1 had better RTV at 6 weeks and higher BIC% in cortical bone at 12 weeks (P < .05). CONCLUSION: In vivo, compared with SLA-2 and RBM, the implant with the strontium-oxide layer displayed slight advantages in new bone formation and osseointegration in the early healing stage. In the later osseointegration stage, the results of SLA-Sr were comparable with other implants.

The optimization of sintering treatment on bovine-derived bone grafts for bone regeneration: in vitro and in vivo evaluation.

Modifications of sintering temperature and treatment time of bovine-derived bone grafts affect their physicochemical properties and further influence biological activity. Three different temperature sintered bovine-derived bone grafts: group I (300 °C 3 h), group II (300 °C 3 h plus 530 °C 6 h), and group III (300 °C 3 h plus 1000 °C 2 h) and Bio-Oss® were characterized and then compared in vitro for their effects on bone marrow stromal cells (BMSCs) migration, proliferation, and differentiation as estimated by cell migration assay, Alkaline phosphatase (ALP) activity assay, and Alizarin red staining. Further, the four bone grafts were implanted into the calvarial defects of rabbits to evaluate bone regeneration and graft degradation. The four deproteinized bovine-derived bone grafts displayed different surface topography. Group II displayed the highest potential of attracting cells. Both groups I and II markedly promote BMSCs differentiation. After 6 and 12 weeks, defects grafted with groups I and II displayed a significant higher bone fraction than defects grafted with group III and Bio-Oss®. Bone graft remnants remained in all four groups. Taken together, sintering at 300 °C for 3 h and sintering at 300 °C for 3 h with an addition of 530 °C for 6 h of bovine-dervied bone grafts displayed potential use in bone regeneration. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:272-281, 2020.

Effect of H2O2/HCl heat treatment of implants on in vivo peri-implant bone formation.

PURPOSE: To investigate the effect of H2O/HCl heat treatment on peri-implant bone formation in vivo. MATERIALS AND METHODS: Twenty Ti-6Al-4V implants and 30 Ti-6Al-4V discs were used in this study. The implants and discs were separated into 2 groups: sandblasted and dual acid-etched group (control group) and sandblasted, dual acid-etched and H2O2/HCl heat-treated group (test group). Surface morphology, roughness, and crystal structure of the discs were analyzed by field-emission scanning electron microscopy, atomic force microscopy, and low angle X-ray diffractometry. The implants were inserted into the femurs of 10 adult white rabbits. Animals were injected with fluorescent bone labels at 1, 5, and 7 weeks following surgery to monitor progress of bone formation. Animals were euthanized 8 weeks postsurgery, and block biopsies were prepared for histologic and histometric analysis. RESULTS: Microscopic evaluation showed the surfaces were quite irregular for both techniques; however, the test surface demonstrated consistently smaller surface irregularities. The differences in Sa values were significant (P = .022). No significant differences were found in the maximum peak-to-valley ratio values (P = .258). X-ray diffractometry analysis showed that titanium dioxide was found on the test surface. New bone was formed on both implant surfaces. The bone-implant contact pattern appeared to produce a broad-based direct contact. Test implants demonstrated 7.13% more bone to implant contact (P = .003) and 15.42% more bone to implant contact for 3 consecutive threads (P = .001) than control implants. Test implants demonstrated 37.04% more bone area 500 microm outside of implant threads (P = .004) and 51.97% more bone area within 3 consecutive threads (P = .001) than control implants. No significant differences were found in bone area within all implant threads between the two groups (P = .069). CONCLUSION: This study demonstrated that implants heat-treated with H2O2/HCl solution enhanced peri-implant bone formation.

Physiochemical characterization and biological effect of anorganic bovine bone matrix and organic-containing bovine bone matrix in comparison with Bio-Oss in rabbits.

Bovine origin matrix has been widely used in clinical applications and investigated by various research institutions. However, the potential factors that influence bone regeneration are still not thoroughly understood and need further investigations. In this study, bone regeneration properties of anorganic bovine bone matrix (ABBM), organic-containing bovine bone matrix (OBBM), and widely acknowledged anorganic bovine bone matrix (Bio-Oss) were compared. Besides, the correlations between physiochemical characterizations and bone regeneration properties of the three xenografts were also investigated. Physiochemical characterizations were measured by special instrumentations. In animal studies, the three xenografts were implanted into 8-mm-diameter cranial defects of 16 New Zealand white rabbits. The biological effects were evaluated by micro-computed tomography and histomorphometric analysis after 6 and 12 weeks of implantation. The physical characterizations showed that anorganic bovine bone matrix and Bio-Oss had more nanostructures, larger surface area, bigger pore volume, and bigger pore size than that of organic-containing bovine bone matrix. The chemical characterizations showed that anorganic bovine bone matrix and Bio-Oss had higher crystallinity than that of organic-containing bovine bone matrix, and organic-containing bovine bone matrix contained organic nitrogen (N) component. In vivo, anorganic bovine bone matrix and Bio-Oss possessed better bone regeneration properties than that of organic-containing bovine bone matrix. Taken together, nanostructures, larger surface area, bigger pore volume, and bigger pore size of xenografts played an active role in new bone formation. Besides, lower crystallinity and organic N element of xenografts produced a positive effect on graft degradation. The abovementioned findings could provide theoretical basis for better choice in clinical applications and better manufacturing hydroxyapatite-derived bone graft in the future.