The influence on surface characteristic and biocompatibility of nano-SnO2-modified titanium implant material using atomic layer deposition technique.

BACKGROUND/PURPOSE: To investigate the surface characteristics of titanium (Ti) implant materials, which were coated with different thicknesses of nanoscale tin oxide (SnO2) using the atomic layer deposition technique, and evaluated its biological performance on human embryonic palatal mesenchyme (HEPM) cells. METHODS: The thickness of the coating layer on Ti was 0 (Ti0), 20 nm (Ti20), 50 nm (Ti50), and 100 nm (Ti100), respectively. The surface morphology was observed with an SEM and AFM. The root mean square roughness of micron-scale (mRq) and nanoroughness (nRq) of Ti discs' surface were measured. The Alamar blue (AB) assay and F-actin fluorescence staining were used to evaluate the biocompatibility, and the osteocalcin (OCN) was measured to clarify the differentiation of HEPM cells on materials. RESULTS: In the coating groups, the mRq was decreased, but the nRq was increased. The spreading and polygonal morphology of HEPMs was apparent in coating groups. On Day 4, the survival rate of HEPM cells on Ti0 was higher than on Ti20 and Ti50. There was no significant difference on Day 7, Day 10, and Day 14. The OCN was significantly higher on Day 14 in all the coating groups than Ti0. CONCLUSION: The results showed that the cell growth was intensified with rough surfaces. However, the OCN and morphology change was prominent when the nanoroughness was increased, which meant the increased nanoroughness might enhance OCN production and improve the tendency of osseointegration. The nanoscale SnO2 coating could increase the ability of bone formation but not cell growth.

Comparison of regular- and slope-configured dental implants placed in the edentulous ridge with height discrepancy: A pilot randomized controlled trial.

BACKGROUND/PURPOSE: Edentulous ridges with height discrepancies (RHDs) could jeopardize the outcome of implant placement. This study aimed at evaluating the outcomes of placing regular- and slope-configured implants in RHDs. METHODS: Patients with >1 mm RHDs requesting implant rehabilitation were recruited and randomly assigned to regular- (control) or slope-configured (test) implant treatment using a submerged installation protocol. Thread exposure (TE) and implant stability quotient (ISQ) were evaluated during implant installation (S1) and uncovered surgery (S2), and marginal bone level (MBL) was evaluated after implant installation (T1) and uncovery (T3), and one year after implant placement (T4). Periodontal status and gingival crevicular fluid (GCF) biomarkers of adjacent teeth were evaluated before implant installation (T0), before uncovery (T2), and at T4. Peri-implant clinical status and peri-implant crevicular fluid (PICF) biomarkers of examined implants were evaluated at T4. RESULTS: Nineteen patients with 17 control and 13 test implants were included. All of the implants survived with acceptable peri-implant health, and PICF biomarkers were at equivalent levels as GCF biomarkers of the adjacent teeth at T4. Compared with the control group, the test group showed reduced TE and equivalent ISQ at S1 and S2, and the loss of MBL was reduced at T4. Regarding the adjacent teeth, all periodontal parameters and GCF biomarkers were slightly decreased from T0 to T2, and the reductions in probing pocket depth and clinical attachment level were slightly greater at T4. CONCLUSION: Slope-configured implants maintained the implant-supporting structures and minimally altered periodontal status of the adjacent teeth in RHDs.

The effects of low-dose 2-hydroxyethyl methacrylate on apoptosis and survival in human dental pulp cells.

BACKGROUND/PURPOSE: 2-hydroxyethyl methacrylate (HEMA) is one of the most major components in dentin bonding systems. Uncured HEMA is eluted through the dentin and harmful to pulp cells. The study aimed to investigate the death pattern, morphological change and factors of human dental pulp cells (HDPCs) cultured with low-dose HEMA. METHODS: HDPCs were cultured with low-dose concentration of HEMA at 0 mM (control), 0.125 mM, 0.25 mM, 1 mM, 2 mM and 4 mM on Day 3 and 5. The cell morphology was observed with F-actin immunocytochemical staining. The flow cytometry was used to analyze the death pattern. NF-κB and Trx-1 were measured using ELISA kits. RESULTS: The major death pattern was early apoptosis and late apoptosis. The morphological characteristics of apoptosis were observed clearly at 4 mM on Day 3 and Day 5. The phosphorylated NF-κB normalized to total NF-κB protein was significantly higher at 2 mM and 4 mM on Day 5. There was no difference of Trx-1 on Day 3, but significantly higher at 0.25 mM and 1 mM on Day 5. The trend line of phosphorylated NF-κB and Trx-1 showed highly positive correlations with HEMA concentration. CONCLUSION: The significant cellular morphology characteristics of apoptosis can be observed at higher dose and longer period after exposed to uncured HEMA. The expression of NF-κB was following the ratio of late apoptosis at longer exposure period. Clinically, the remaining dentin thickness should be enough to decrease HEMA concentration and thus to protect pulp cells free from harm.