Comparative evaluation of BioHPP and titanium as a framework veneered with composite resin for implant-supported fixed dental prostheses.

STATEMENT OF PROBLEM: High rates of veneering chipping are a common prosthodontic complication of restorations with a titanium framework. A new bio high-performance polymer (BioHPP) based on polyetheretherketone (PEEK) has been introduced for denture superstructures. Clinical reports suggest that BioHPP could be used as an alternative framework material to support complete-arch restorations. However, peer-reviewed information is lacking regarding the performance of BioHPP as a framework material for implant-supported screw-retained fixed dental prostheses (FDPs) veneered with composite resin. PURPOSE: The purpose of this in vitro study was to evaluate and compare the bond strength of modified PEEK (BioHHP) and titanium with a veneering composite resin and compare the marginal fit and fracture resistance of implant-supported screw-retained FDPs fabricated by using computer-aided design and computer-aided manufacturing (CAD-CAM) frameworks veneered with composite resin. MATERIAL AND METHODS: A composite resin was bonded to 2 framework materials (n=20/group): pure titanium (Ti) and BioHPP (Bi). The shear bond strength (SBS) was determined after 24-hour wet storage. Furthermore, 20 3-unit CAD-CAM BioHPP and titanium frameworks were fabricated (n=10/group). The marginal fit between frameworks and abutments was evaluated by scanning electron microscopy by using the single-screw test. After thermocycling and mastication simulation, the fracture resistance of FDPs veneered with the composite resin was examined. The independent sample t test was used to evaluate differences (α=.05). RESULTS: Significantly higher shear bond strengths were obtained in group Bi (31.1 ±3.5 MPa) than in group Ti (20.5 ±1.8 MPa). The mean marginal gap width was 19 ±4 µm in group Bi and 16 ±6 µm in group Ti. Statistical tests showed no significant differences (P>.05). After loading, veneering chipping was observed at a load of 1960 ±233 N in group Ti. Although the BioHPP frameworks fractured at 1518 ±134 N, no chipping occurred. CONCLUSIONS: The bond strength of BioHPP with the composite resin was greater than that of titanium. CAD-CAM BioHPP frameworks exhibit good marginal fit and fracture resistance. BioHPP may be a suitable alternative to metal as a framework to be veneered with composite resin.

[Cytotoxicity of a new type silicone rubber for maxillofacial prosthesis: an in vitro evaluation].

This study evaluated the cytotoxicity of a new type silicone rubber for maxillofacial prosthesis, which was developed by the present authors. According to the GB/T16886. 5- 2003, the samples were prepared and tested with cell counting kit-8 (CCK-8) assay, the relative growth rate (RGR) was calculated, and morphology of L929 cells were observed by scanning electron microscope and phase contrast microscope. The results showed that RGR of L929 cells were 91.65% (24 h), 87.03% (48 h), 87.30% (72 h), respectively, and the level of cytotoxicity was grade 1. The L929 cells showed typical fusiform shape and their morphology did not changed significantly after 24 h, 48 h and 72 h. These data indicated that the newly-developed silicone rubber material, as a maxillofacial prosthesis material, should be a safe biomaterial.

[Zoledronic acid incorporated in chitosan/calcium phosphate ceramic: characterization and in vitro response of osteoblast cells].

OBJECTIVE: To develop a new local delivery system, zoledronic-acid-loaded chitosan/calcium phosphate ceramic, and to determine its characterization and in vitro response of osteoblast cells. METHODS: Zoledronic-acid-loaded chitosan/calcium phosphate ceramic were prepared by solution casting method at a concentration of 10(-5), 10(-4), and 10(-3) mol/L, respectively. The physicochemical properties of the resulting materials were determined using SEM and FTIR. Drug absorbance was measured using CCK-8 colorimetric assay and alkaline phosphatase assay to detect the effect of drug-loaded materials on the proliferation and differentiation of osteoblasts. RESULTS: After ZOL loading, SEM showed that porous calcium phosphate ceramic was coated with chitosan evenly. The IR spectra indicated that drug absorption peaks were shifted and a new one was formed for the drug-loaded biomaterials. The material at the highest concentration could inhibit the proliferation and alkaline phosphatase activities of osteoblast cells, but no such effect was found at a drug-loading concentration of 10(-4)-10(-5) mol/L. CONCLUSION: We confirmed that the local delivery system in this study has ability of loading ZOL. The biomaterial with high drug concentrations inhibits the proliferation and differentiation of osteoblasts, but not when the drug concentrations are low.

Scutellarin Loaded on Ultradeformable Nanoliposome Scutellarin EDTMP (S-UNL-E) Promotes Osteogenesis in Osteoporotic Rats.

Scutellarin is known as a safe, effective, and low-cost traditional Chinese medicine and has a variety of biological activities. Studies reported that the scutellarin loaded on ultradeformable nanoliposome scutellarin EDTMP (S-UNL-E) could promote osteoblast differentiation and bone formation in vitro. However, its effect on promoting osteogenesis in vivo is still unclear. In this study, pharmacology network and transcriptome sequencing were used to screen the potential targets and pathways of scutellarin in treating osteoporosis. The female Sprague-Dawley (SD) rats were operated on with bilateral oophorectomy and femoral defect to establish an osteoporosis model and then treated separately with bone dust, single scutellarin, 40 mg/kg ultradeformable nanoliposome scutellarin (S-UNL), and the optimal concentration of 40 mg/kg S-UNL-E for a total of 56 d to detect the parameters of trabecular bones. And qRT-PCR and western blot were performed to determine the expression of prostaglandin-endoperoxide synthase 2 (PTGS2), alkaline phosphatase (ALP), transcription factor 4 (TCF4), and ß-catenin. Results of microscopic computed tomography (Micro-CT) of trabecular bones showed that single scutellarin, S-UNL, and S-UNL-E all promoted the bone formation of osteoporotic rats, in which S-UNL-E manifested the most remarkable therapeutic effect. And it is found that 40 mg/kg of S-UNL-E increased the expression of PTGS2, ALP, TCF4, and ß-catenin, which indicated that S-UNL-E stimulated the secretion of ALP in bone defect areas to promote bone healing, and increased PTGS2 expression thereby enhancing the transcription and translation of key gene ß-catenin and TCF4 in the Wnt/ß-catenin signaling pathway to treat osteoporotic rats.

Graphene-Based Nanomaterials for Dental Applications: Principles, Current Advances, and Future Outlook.

With the development of nanotechnology, nanomaterials have been used in dental fields over the past years. Among them, graphene and its derivatives have attracted great attentions, owing to their excellent physicochemical property, morphology, biocompatibility, multi-differentiation activity, and antimicrobial activity. In our review, we summarized the recent progress about their applications on the dentistry. The synthesis methods, structures, and properties of graphene-based materials are discussed. Then, the dental applications of graphene-based materials are emphatically collected and described. Finally, the challenges and outlooks of graphene-based nanomaterials on the dental applications are discussed in this paper, aiming at inspiring more excellent studies.

Modified Disk-Up Sinus Reamer for Sinus Floor Elevation and Simultaneous Implant Placement: An Animal Study with Miniature Pigs.

Objective: The disk-up sinus reamer (DSR) is a modified instrument used to elevate the maxillary sinus floor. This study aimed to compare the effects of modified DSR sinus floor elevation (DSFE) with osteotome sinus floor elevation (OSFE), both with simultaneous implant placement. Methods: Twelve miniature pigs were treated with DSFE on one side and OSFE on the other. Implants 9 mm in length were placed in six pigs without grafting, while implants 11 mm in length were placed in the other six pigs with grafting. After submerged healing for 3 months, vertical bone gain (VBG), general and histological observation, and bone contact ratio (BCR) were analyzed. Results: The mean maxillary residual bone height (RBH) when implants were placed was 6.45 ± 0.36 mm. In the no-grafting group, DSFE and OSFE had a similar VBG after 3 months. The grafting group with DSFE recorded a significantly higher VBG (VBG0: 7.83 ± 0.44 mm, VBG1: 7.54 ± 0.40 mm) than the graft group with OSFE (VBG0: 5.45 ± 0.56 mm, VBG1: 4.34 ± 2.15 mm) (p < 0.05). One implant became loose and the sinus mucosa of three pigs appeared metallic in color on the control side (OSFE). Conclusions: The effect of OSFE and DSFE is similar when there is no need for grafting. DSFE seems a better alternative method for sinus floor elevation with grafting when more VBG is needed.

Scutellarin enhances osteoblast proliferation and function via NF-κB-mediated CXCR4 induction.

In the current study, we aimed to examine the function of scutellarin on human osteoblast proliferation and osteogenic function. The results indicated that scutellarin enhanced osteoblast proliferation over a seven day period. This increase in cell proliferation was associated with corresponding increases in osteoblast activity, as measured by alkaline phosphatase (ALP) secretion, intracellular calcium ion influx, and calcium deposition. These anabolic effects were associated with C-X-C chemokine receptor type 4 (CXCR4) mRNA levels and protein induction. Knockdown of CXCR4 reversed the scutellarin-induced increases in cell proliferation, ALP activity, and calcium deposition. Furthermore, scutellarin increased p65 phosphorylation in a dose-dependent manner, which resulted in the increased binding of phosphorylated p65 to the CXCR4 gene promoter region, to increase CXCR4 protein expression. p65 phosphorylation inhibition resulted in a decrease in CXCR4 protein expression. A p65 inhibitor blocked scutellarin-induced increases in osteoblast proliferation and function. Moreover, in a rat model of estrogen-deficient osteoporosis, scutellarin restored ovariectomy-induced bone loss in mice. Taken together, both cellular and animal models support the novel findings that scutellarin increased osteoblast proliferation and function through NF-κB/p65-mediated CXCR4 induction.

Influence of Maxillary Sinus Width on Transcrestal Sinus Augmentation Outcomes: Radiographic Evaluation Based on Cone Beam CT.

BACKGROUND: Maxillary sinus elevation is a predictable procedure to vertically enhance bone volume in the posterior maxilla for successful implant placement. It is speculated that graft bone resorption and remodeling which require angiogenesis may be affected by the dimensions of maxillary sinus cavity. PURPOSE: The aim of this study is to investigate the effect of sinus width (SW) on the outcomes of transcrestal sinus lift with simultaneous implant placement based on cone beam CT (CBCT). MATERIALS AND METHODS: A total of 57 elevated sites in 33 patients were included in this study. All the patients were treated with transcrestal sinus lift procedure associated with simultaneous implant placement using a composite graft material of autogenous bone and Bio-Oss. For each patient, CBCT scans were performed preoperatively, immediately after surgery and 6 months after surgery. Measurements of the linear parameters were conducted on the preoperative and postoperative CBCT images. The correlation of SW with graft resorption (GR) was analyzed using Pearson's correlation test with or without the classification of residual bone height. RESULTS: The average width of maxillary sinus was 13.68 ± 2.66 mm. The mean height of apical graft bone decreased from 2.85 mm immediately after surgery to 1.38 mm after 6 months. A positive association between SW and GR (r = 0.323, p = .014) was found in general. CONCLUSION: The findings show that graft bone resorption in elevated sinus has a positive correlation with the SW.

Sinus Width Analysis and New Classification with Clinical Implications for Augmentation.

PURPOSE: To measure the distances between the medial and lateral sinus wall (sinus width [SW]) at different levels on cone beam computed tomography (CBCT) and apply those SW values to formulate a new sinus classification. MATERIALS AND METHODS: Edentulous sites adjacent to maxillary sinuses with inadequate residual bone height (RBH) were included from the CBCT database. SW was measured at the heights of 1, 3, 5, 7, and 9 mm from the sinus floor. Mean SW was stratified into different groups by RBH, study sites (first and second premolars and molars), and measurement levels. Statistical analyses were conducted with commercially available software (IBM SPSS Statistics 19, SPSS Inc., Chicago, IL, USA). RESULTS: A total 186 patients (mean age 50.4 years) with 267 edentulous sites were included. Mean SW was wider at molar sites, higher measurement levels, and sites with less RBH. Narrow, average, or wide sinuses were classified based on the 33rd and 67th percentile SW values at 1-, 5-, and 9-mm measurement levels, respectively. CONCLUSIONS: SW at different levels relating to sinus floor elevation was measured. The proposed classification could contribute to estimate the difficulty of sinus augmentation, useful for the selection of surgical approaches. Further studies are required to testify its clinical implications.

Masticatory efficiency and oral health-related quality of life with implant-retained mandibular overdentures.

OBJECTIVES: To evaluate masticatory efficiency (ME) and oral health-related quality of life (OHRQoL) in patients rehabilitated with implant-retained mandibular overdentures. METHODS: In this randomized controlled clinical trial, 50 edentulous patients visiting the Implant Center and Department of Prosthodontics, West China College of Stomatology, Sichuan University, Chengdu, China between June 2010 and June 2012 were selected and received 2 implant-retained mandibular overdenture treatments. All patients were rehabilitated with maxillary complete dentures. The ME and OHRQoL were determined both one month before the mandibular complete denture was anchored to the osseointegrated implants, and 6 months after anchoring. Paired t-tests were used to compare means of ME, and oral health impact profile-49 (OHIP-49)  domains scores between pre- and post-implant. Linear regression models were utilized to seek correlations between ME and OHIP domains scores. RESULTS: The ME increased from pre- to post-implant retained mandibular overdentures significantly (p<0.001). The total OHIP score and 4 subscales scores were changed significantly from pre- to post-implant; namely, functional limitation, psychological discomfort, physical disability, and physical pain. The total OHIP score, functional limitation, physical disability, and physical pain subscale scores were related to ME. CONCLUSION: Implant-retained mandibular over dentures can significantly improve patients' ME and OHRQoL. The improvement in OHRQoL is mainly because of the improved ME. An improved chewing experience, and pain relief also contributes to improvement of OHRQoL. 

Osteoblast response to titanium surfaces coated with strontium ranelate-loaded chitosan film.

PURPOSE: Improving the peri-implant bone quality has notable clinical value in cases of osteoporosis following implant insertion. MATERIALS AND METHODS: In this study, strontium ranelate-loaded chitosan film was produced on a titanium surface in different concentrations of strontium ranelate (SR) (0, 2, 20, 40, and 80 mmol/L of the strontium ion [Sr2+]) with the expectation of utilizing the bone healing-enhancement effect of Sr2+. The physicochemical properties of SR-loaded chitosan films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The release/dissolution mechanism was tested by inductively coupled plasma optical emission spectrometry (ICP-OES), and in vitro cell responses were evaluated using primary osteoblasts (POBs) in terms of cell proliferation, alkaline phosphatase (ALP) activity, and quantitative analysis of key osteoblastic gene expression. RESULTS: XRD and FTIR observation showed that only a few SRs reacted chemically with chitosan through hydrogen bonds or conjugate action. The initial burst release (70% to 85%) of Sr2+ occurred in the first 3 days and was followed by a slower release stage. At a low concentration (2 mmol/L or 20 mmol/L), SR-loaded chitosan film promoted cell responses of POBs with enhanced proliferation, ALP activity, and expression levels of bone morphogenetic protein 2 (BMP-2), runt-related transcription factor 2 (Runx-2), ALP, and osteocalcin, but at a high concentration (40 mmol/L or 80 mmol/L), it inhibited POB growth. CONCLUSION: These results indicated that SR-loaded chitosan film on a titanium surface promotes osteoblast proliferation and differentiation in a dose-dependent manner, which may represent a new approach in the treatment of a titanium implant.

The inlay osteotome sinus augmentation technique for placing short implants simultaneously with reduced crestal bone height. A short-term follow-up.

OBJECTIVE: To display an inlay technique of osteotome sinus floor elevation using a trephine combined with simultaneous short implant placement where the residual bone height (RBH) is less than 5 mm, as well as to evaluate the clinical effect in a prospective study. MATERIAL AND METHODS: Fifty short implants were installed in 32 patients in the severely atrophic posterior maxilla immediately after sinus floor elevation between January 2010 and October 2012. An inlay osteotome sinus augmentation technique using a trephine was applied in the operation. The mean residual bone height adjacent to or beneath the sinus was 3.34 mm, ranging from 0.96 mm to 4.96 mm. It was rarely necessary to add graft material from bovine sources in this therapy. With the purpose of bite training and soft tissue reforming, the temporary crowns were fixed after 6 months. The final prostheses were restored 3 months later. The stability and osseointegration of the implants were clinically evaluated, also the bone height gain around the implants was measured. RESULTS: The survival rate was 100% during the study period with this procedure. Each of the implants, loaded without pain or any subjective sensation, was clinically stable. No implants had detectable sinus membrane perforation during operation. The radiographic results demonstrated that the bone height gain was 5.38 mm after the surgery. CONCLUSION: Based on the results and within the limits of the present study, it can be suggested that short implant placement in conjunction with this inlay osteotome sinus augmentation technique could yield predictable clinical results for edentulous posterior maxillary region with RBH less than 5 mm. Besides, from the clinical point of view, these techniques may reduce the indication for complex invasive procedures and simplify treatment in the posterior.