A bioactive and anti-bacterial nano-sized zirconium phosphate/GO (nZrP/GO) composite: Potential use as a coating for dental implants?

OBJECTIVE: Dental implants fabricated from titanium have several limitations and therefore, alternative materials that fulfil the criteria of successful dental implant (bioactivity and anti-bacterial activity) need to be considered. Polyether ether ketone (PEEK) has been suggested to replace titanium implants. However, this material needs surface modification to meet the appropriate criteria. A nano-sized zirconium phosphate/GO (nZrP/GO) composite coating was prepared to improve PEEK's biological qualities. METHODS: Polished and cleaned PEEK discs were coated with the composite of nZrP doped with 1.25 wt% GO by the soft-template method. To analyze the composite coating, X-ray, atomic force microscopy, and field emission scanning electron microscopy-energy dispersive spectroscopy were used. The adhesion of the coating to PEEK was measured by adhesive tape test. By measuring the optical contact angle, the coated and non-coated samples' differences in wettability were evaluated. Antimicrobial activity was evaluated against S. aureus and E. coli and cytotoxicity tested employing gingival fibroblasts and osteoblast-like cells. RESULTS: The nZrP/GO composite coating was 23.45 µm thick, was irregular and attached strongly to the PEEK surface. Following coating, the water contact angle dropped to 34° and surface roughness to 13 nm. The coating reduced the count of bacteria two-fold and was non-cytotoxic to mammalian osteoblast-like cells and fibroblasts. A precipitation of nano-calcium-deficient apatite was observed on the surface of the nZrP/GO coating following a 28-day immersion in SBF. SIGNIFICANCE: PEEK-coated with nZr/GO coating is a good candidate as dental implant.

Polyether ether ketone coated with nanohydroxyapatite/graphene oxide composite promotes bioactivity and antibacterial activity at the surface of the material.

Polyether ether ketone (PEEK) is considered an alternative material for manufacturing dental implants. However, PEEK lacks bioactivity and antibacterial action. In a series of experiments designed to enhance the surface properties of PEEK, we present a nanohydroxyapatite (nHA) and graphene oxide (GO) composite as a coating for PEEK-based dental implants to improve biological properties and antibacterial action. PEEK discs were polished, cleaned, and coated with the composite consisting of nHA particles doped with 0.75 wt% graphene oxide by a micro-emulsion technique according to patent US8,206,813. X-ray diffraction, field emission scanning electron microscopy-energy dispersive spectroscopy, and atomic force microscopy were utilized to characterize the composite coating. The wettability of the coated and non-coated samples was assessed by optical contact angle measurement. Antibacterial action of the composite coating was explored against S. aureus and E. coli and cytotoxicity determined utilizing osteoblast-like cells and gingival fibroblasts. The findings showed that the nHA/GO composite coating, approximately 1.3 µm thick, was homogenous with few micro-cracks and adhered to the PEEK surface. The surface roughness was reduced to 21.26 nm and the wettability was improved to 54.6° after coating with the composite coating. Antibacterial activity was moderate, killing 99% of S. aureus and E. coli, with acceptable levels of cytotoxicity to mammalian osteoblast-like cells and gingival fibroblasts.

A novel bioactive glass/graphene oxide composite coating for a polyether ether ketone-based dental implant.

Polyether ether ketone (PEEK) is a biocompatible material that lacks antimicrobial activity and bioactivity; therefore, is not appropriate for use as a dental implant. To overcome these deficiencies, a novel composite coating of bioactive glass and graphene oxide was prepared. PEEK discs were polished, cleaned, and the surface treated with sulfuric acid for 15 min. The composite coating consisted of bioactive glass produced by the sol-gel route and doped with 0.75 wt% graphene oxide. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy-energy dispersive spectroscopy analyses were employed to characterize the composite coating, and the coating adhesion strength quantified using a pull-off test. Cytotoxicity was assessed using osteoblast-like cells and gingival fibroblasts. The wettability of the coated and non-coated samples was determined by optical contact angle assessment, and bioactivity was assessed by immersion in simulated body fluid. The results revealed that the bioactive glass/graphene oxide composite coating, approximately 7 µm thick, was transparent, homogenous with few microcracks and microporosities, but adhered strongly and was not cytotoxic to either osteoblast-like cells or gingival fibroblasts. The wettability of the PEEK sample was increased to <20° after coating with the composite, and apatite formation was detectable after 14 days of immersion in simulated body fluid.

MgF2- containing glasses as a coating for titanium dental implant. I- Glass powder.

Bioactive glasses can be used to coat titanium implants to promote osseointegration. However, incorporating elements such as magnesium, zinc and fluoride into bioactive glasses might have a negative effect on bioactivity or the coefficient of thermal expansion of the glass. In this study, the impact of substituting MgO for CaO on physical properties and bioactivity of glass containing 1 mol % MgF2 was assessed. Seven glasses were produced by melt-quenched route. The glasses comprise (SiO2, CaO, Na2O, MgO, MgF2, K2O and P2O5) and were characterized utilizing XRD, DSC, FTIR and dilatometry analyses. The bioactivity of these glasses was investigated in biological fluids. The results showed that these glasses have wide sintering windows, low TECs and low glass transition and softening temperatures. The bioactive glasses containing up to 13.3 mol% MgO were able to form surface apatite within a short time period; whereas glasses containing ≥16.13 mol% demonstrated only structural variations with no clear sign of apatite precipitation.

Pyogenic granuloma: Clinicopathological and treatment scenario.

BACKGROUND: Oral pyogenic granuloma is a soft-tissue lesion of the oral mucosa. This lesion has a tendency to reoccur after surgical excision. MATERIALS AND METHODS: A total of 28 patients underwent surgical excision of pyogenic granuloma in the period from September 2014 to May 2016. Two surgical techniques were used to remove pyogenic granuloma: simple excision with root planing and modified excision with deep curettage. RESULTS: Females (54%) were slightly more predominant than males (46%). The upper and lower jaws were almost equally affected by the lesion with more predilection toward the posterior region. The size of the lesion ranged from 0.5 to 3 cm in diameter with slow-growing rate. Rural residents were more affected (57%) than urban people. The lesion appears clinically as a small red mass with sessile base, and these clinical features were similar in pregnant and nonpregnant women. The recurrence rate was 14.8% and seen only in patients treated by simple excision. Histopathological feature was consistent with inflammatory hyperplastic lesion, and there was no radiographic evidence of bone resorption associated with the lesion. CONCLUSION: Modified excision with deep curettage prevents the recurrence of the lesion after 1-year follow-up.