The biocompatibility and mechanical properties of plasma sprayed zirconia coated abutment

PURPOSE@#. The aim of this study was to evaluate the clinical performance and reliability of plasma sprayed nanostructured zirconia (NSZ) coating. @*MATERIALS AND METHODS@#. This study consisted of three areas of analysis: (1) Mechanical property: surface roughness of NSZ coating and bond strength between NSZ coating and titanium specimens were measured, and the microstructure of bonding interface was also observed by scanning election microscope (SEM). (2) Biocompatibility: hemolysis tests, cell proliferation tests, and rat subcutaneous implant test were conducted to evaluate the biocompatibility of NSZ coating. (3) Mechanical compatibility: fracture and artificial aging tests were performed to measure the mechanical compatibility of NSZcoated titanium abutments. @*RESULTS@#. In the mechanical study, 400 μm thick NSZ coatings had the highest bond strength (71.22 ± 1.02 MPa), and a compact transition layer could be observed. In addition, NSZ coating showed excellent biocompatibility in both hemolysis tests and cell proliferation tests. In subcutaneous implant test, NSZcoated plates showed similar inflammation elimination and fibrous tissue formation processes with that of titanium specimens. Regarding fatigue tests, all NSZ-coated abutments survived in the five-year fatigue test and showed sufficient fracture strength (407.65-663.7 N) for incisor teeth. @*CONCLUSION@#. In this study, the plasmasprayed NSZ-coated titanium abutments presented sufficient fracture strength and biocompatibility, and it was demonstrated that plasma spray was a reliable method to prepare high-quality zirconia coating.

Efficacy of sodium bicarbonate buffered versus non-buffered lidocaine with epinephrine in inferior alveolar nerve block: A meta-analysis

INTRODUCTION: This systematic review evaluated the use of buffered versus non-buffered lidocaine to increase the efficacy of inferior alveolar nerve block (IANB). MATERIALS AND METHODS: Randomized, double-blinded studies from PubMed, Web of Science, Cochrane Library, Embase, and ProQuest were identified. Two of the authors assessed the studies for risk of bias. Outcomes included onset time, injection pain on a visual analog scale (VAS), percentage of painless injections, and anesthetic success rate of IANB. RESULTS: The search strategy yielded 19 references. Eleven could be included in meta-analyses. Risk of bias was unclear in ten and high in one study. Buffered lidocaine showed 48 seconds faster onset time (95% confidence interval [CI], −42.06 to −54.40; P < 0.001) and 5.0 units lower (on a scale 0–100) VAS injection pain (95% CI, −9.13 to −0.77; P=0.02) than non-buffered. No significant difference was found on percentage of people with painless injection (P = 0.059), nor success rate (P = 0.290). CONCLUSION: Buffered lidocaine significantly decreased onset time and injection pain (VAS) compared with non-buffered lidocaine in IANB. However due to statistical heterogeneity and low sample size, quality of the evidence was low to moderate, additional studies with larger numbers of participants and low risk of bias are needed to confirm these results.

Evaluation of the efficiency of different instrumentation for root canal retreatment using micro-computed tomography / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish the three-dimensional model of human permanent premolars based on Micro-computed tomography (Micro-CT) data, and evaluate the efficiency quantitatively of two different instrumentations for root canal retreatment.</p><p><b>METHODS</b>Forty extracted permanent premolars for the reason of orthodontic treatment were collected, prepared by using ProTaper Ni-Ti files and filled by cold gutta pertscha lateral condensation technique. The subjects were scanned by Micro-CT. Forty teeth were randomly divided into two groups and retreated by K-Flexo files and ProTaper Universal retreatment system respectively. Then all subjects were scanned again, and the mean percentage of remaining filling materials and the scores of remaining filling materials presented in upper, middle and apical 1/3 of the canal were calculated.</p><p><b>RESULTS</b>Mean percentage of the remaining filling materials by K-Flexo files was lower than that by ProTaper Universal retreatment system (P=0.005). The scores demonstrated that K-Flexo files had greater efficiency than ProTaper Universal retreatment system when retreating the apical 1/3 of canal (P<0.05).</p><p><b>CONCLUSION</b>This study shows that both techniques could not remove filling materials completely.</p>