OBJECTIVETo determine the influence of different surface conditioning methods on bonding strength of low fusing porcelain (La-Porcelain) and titanium.

METHODSThe surface of the samples were sandblasted for 2 min with 80-250 microns Al2O3 or coated for two times with Si-couple agent or conditioned by pre-oxidation. The shear bond strength was examined by push-type shear test with a speed of 0.5 mm/min in a universal testing machine. Scanning electron microscopy (SEM) and electron probe micro-analyzer (EPMA) were employed to explore the relationship between bonding strength and microstructures, as well as the element diffusion at the interface between porcelain coating and titanium when heated at 800 degrees C.

RESULTSBonding strength was not statistically different (P > 0.05) after sandblasting with Al2O3 in particle size ranged from 80 microns to 250 microns. When a Si-couple agent was used, bond of porcelain to titanium was significantly lower (P < 0.05). The shear bond strength of the porcelain to the pre-oxidized titanium surface remained unchanged after heating (P > 0.05). The SEM results revealed integrity of porcelain and titanium.

CONCLUSIONLa-Porcelain showed a small effect of surface coarseness. Sandblasting the titanium surface with 150-180 microns Al2O3 can be recommended as a method for better bonding between La-Porcelain and titanium. The Si-couple agent coating and pre-oxidation of titanium surface is unnecessary.

Aluminum Oxide ; chemistry ; Dental Bonding ; Dental Materials ; Dental Porcelain ; chemistry ; Humans ; Lanthanum ; chemistry ; Materials Testing ; Metal Ceramic Alloys ; chemistry ; Surface Properties ; Tensile Strength ; Titanium ; chemistry

OBJECTIVETo study the microstructure of the Ag-nHA-nTiO2/PA66 membrane and investigate its biocompatibility.

METHODSThe microstructure of Ag-nHA-nTiO2PA66 membrane and e-polytetra fluoroethylene (e-PTFE) membrane were observed by light microscope and scanning electron microscope(SEM). MG63 osteoblast-like cells were cultured on the two kinds of membrane and blank group. The cell proliferation was checked by methyl thiazolyl tetrazolium (MTT) method and alkaline phosphatase (ALP) activity was detected by enzyme linked immunosorbent assay (ELISA). The adhesion and proliferation of the cells on the two kinds of membrane was observed by SEM.

RESULTSThe Ag-nHA-nTiO2/PA66 membrane was composed of the obverse face and the opposite face. The obverse face was porous and the opposite face was smooth. Microstructures of the obverse and the opposite face of the e-PTFE membrane were same. The e-PTFE membrane showed many tiny lined cracks in elliptic structure. MTT assay and ALP measurement showed that there were no significant difference between each of the two membrane groups and the blank (P > 0.05). The adhesion and proliferation of cells on the Ag-nHA-nTiO2/PA66 membrane were better than the e-PTFE membrane.

CONCLUSIONAg-nHA-nTiO2/PA66 membrane has no negative effects on the growth of osteoblast-like cells. Ag-nHA-nTiO/PA66 membrane is biocompatible and its microstructure is appropriate as a guided bone regeneration materials.

Anti-Bacterial Agents ; Bone Regeneration ; Cell Proliferation ; Durapatite ; Nanocomposites ; Nylons ; Osteoblasts

Objective : To investigate the effect of immediate and delayed implant placement on dimensional changes in hard and soft tissues as well as esthetic outcomes. Methods : A total of 40 maxillary single anterior teeth with a dehiscence defect on the labial bone (≤4 mm) were categorized into two groups according to the timing of implant placement: immediate implant placement (n = 20) or delayed implant placement (n = 20). Guided bone regeneration (GBR) was conducted at the sites using a flap approach, and the implants were given immediate provisionalization. Implant survival rates, dimensional changes in hard and soft tissues during the six- and twelve-month follow-ups, and pink esthetic scores (PESs) were measured. Results : The implant survival rates in both groups were 100%, and no complications occurred during the follow-up time. There was no significant difference between the two groups at the measurement sites in the dimensional change of hard and soft tissues during the six- and twelve-month follow-ups. The largest resorption was observed at the implant neck, with a loss of (1.29 ± 0.71) mm in the immediate implant placement group and (1.43 ± 0.19) mm in the delayed implant placement group. The mean PES scores were (10.95 ± 1.51) for the immediate implant placement group and (11.05 ± 1.23) for the delayed implant placement group. Conclusion Immediate implantation or delayed implantation combined with GBR and immediate provisionalization might both be a prospective treatment strategy for a maxillary single anterior tooth with a dehiscence defect on the labial bone.

Objective: To study the postoperative soft and hard tissue changes and aesthetic effect of immediate implantation and provisionalization (IIPP) combined with guided bone regeneration (GBR) for a single anterior maxillary tooth with a thin facial bone phenotype. Methods : A total of 34 patients with thin facial bone (<1 mm) were categorized into two groups: a flapped GBR group and a flapless group. Tooth extraction and IIPP were conducted at the sites in both groups. Implant survival rates, dimensional changes in soft and hard tissues during the six- and twelve-month follow-ups, the pink esthetic score (PES) and patient satisfaction scores at the twelve-month follow-up were measured. Results : The implant survival rates were 100% in both groups, and no complications occurred during the 12 months after surgery. The facial bone thickness remained over 2 mm on all measured sides, and the height of the facial bone crest remained at 1.39 mm at the 12-month follow-up in the flapped GBR group, while the facial bone thickness remained less than 2 mm on all measured sides, and the height of the facial bone crest remained at 1.03 mm at the 12-month follow-up in the flapless group. The absorption of facial bone at all measured sides in the flapped GBR group was greater than that in the flapless group (P<0.05). There was no significant difference between the two groups in the dimensional changes of labial soft tissues during the six- and twelve-month follow-ups (P>0.05). The mean PES scores were 10.29 ± 2.34 for the flap GBR group and 10.12±1.78 for the flapless group (P = 0.807). The mean patient satisfaction scores were 8.65 ± 1.27 in the flapped GBR group and 8.76 ± 1.25 in the flapless group, and the patients in both of the groups were satisfied with the esthetic outcomes (P = 0.787). Conclusion IIPP combined with GBR might be a prospective treatment strategy for a single anterior maxillary tooth with a thin facial bone phenotype, but the esthetic risks should never be ignored.

MXenese is a type of two-dimensional inorganic compound in materials science that is composed of transition metal carbides, nitrides, or carbonitrides with several atomic layer thicknesses. Owing to the presence of hydroxyl groups or terminal oxygen groups on the surface of MXene materials, they exhibit metallic conductivity similar to that of transition metal carbides. Owing to their excellent optical, mechanical, electrothermal, and biocompatible properties, emerging 2D MXenes are widely used in biomedical fields such as tissue engineering, antimicrobial drugs, photothermal therapy, drug/gene delivery, sensing, and regenerative medicine. In this paper, we review the methods for synthesizing and modifying MXene-based composites, their research and application in stomatology, and their development prospects and challenges in the clinical application of tissue engineering. The biocompatibility and osteogenic properties of MXene and its nanocomposites have the potential to promote cell proliferation and bone regeneration. The anti-bacterial adhesion and biofilm formation properties can be applied to implant coating and prevent caries. The excellent photothermal, conductive, and mechanical sensitivity of this agent make it suitable for drug delivery, bio-photothermal therapy, immune signal sensing, and gene detection. On this basis, MXene has recently achieved outstanding results in the fields of stomatology, including bone tissue engineering, antimicrobial, drug delivery, physical and mechanical enhancement of dental biomaterials, oral cancer treatment, and periodontal disease monitoring. However, research on the prevention and treatment of refractory oral diseases has not yet been reported. At present, the properties and surface modification of MXene-based nanomaterials are relatively well understood. Future studies should focus on the dose-dependent biosafety, cellular and molecular mechanisms, and signaling pathways of MXene to fully exploit its unique advantages in oral clinical and tissue engineering fields.