The Influence of Storage in Saline or Irradiation by Ultraviolet on Surface Hydrophilicity of Implant and Osseointegration: An Experimental Study in Rabbits.

Storage in aqueous solution or ultraviolet (UV) irradiation can retain or regain the hydrophilicity of titanium implant surface. In this study, 3 types of commercial titanium implants were used: ZBL (ZDI Bone Level), CEL (C-tech Esthetic Line), and modSLA (Straumann SLActive). ZBL and CEL implants were treated with UV irradiation for 4 hours. Surface characterization of the 4 groups (ZBL, ZBL-UV, CEL-UV, and modSLA) was evaluated by scanning electron microscopy and contact angle measurements. The in vivo bone response was evaluated by removal torque (RTQ) tests and histomorphometric analysis at 3, 6, and 12 weeks postimplantation. A total of 144 implants and 36 rabbits were used for experiments according to a previously established randomization sequence. The ZBL-UV, CEL-UV, and modSLA groups were hydrophilic, and nanostructures were observed on the modSLA implant surface. ModSLA achieved better RTQ value than ZBL at 12 weeks (P < .05). For histomorphometric analysis, ZBL-UV and CEL-UV implants showed higher bone area values in the cancellous bone zone at 6 weeks than did modSLA and ZBL implants (P < .05). In the cortical bone zone, all groups showed comparable bone-to-implant contact at all healing time points (P > .05). Both storage in saline and UV irradiation could retain or provoke hydrophilic surfaces and improve osseointegration. Compared with storage in saline, UV irradiation displayed slight advantages in promoting new bone formation in cancellous bone zone at an early stage.

Biomechanical and Morphometric Evaluation of a Strontium-Incorporated Implant and Four Commercially Available Implants: A Study in Rabbits.

PURPOSE: Strontium has shown a positive effect on osseointegration in experiments. This study compared surface characterization and osseointegration of a strontium-incorporated implant with four commercial implants with different surface treatments. MATERIALS AND METHODS: A strontium-oxide layer was created by hydrothermal treatment on the surface of the implant (SLA-Sr). Surface characterizations were observed using a scanning electron microscope, three-dimensional (3D) optical microscope, and x-ray energy-dispersive spectrometry. Implants of different surface treatments including resorbable blasting media (RBM), sandblasting with large grit and acid etching (SLA-1, SLA-2), sandblasting and thermal acid etching (STA), and SLA-Sr were implanted into the proximal tibiae and femoral condyles of rabbits. Biologic effects were evaluated by removal torque testing and histomorphometric analysis after 3, 6, and 12 weeks of implantation. RESULTS: Nanostructures were observed on the surface of SLA-Sr and STA. Calcium (Ca) was detected on the surface of RBM. Sr was detected on the surface of SLA-Sr. SLA-1 and STA had greater surface roughness than SLA-2, SLA-Sr, and RBM (P < .05). In vivo, SLA-Sr achieved better removal torque value (RTV) than that of RBM and SLA-2 at 3 weeks (P < .05), as well as increased bone area ratio (BA%) in cortical bone compared with RBM at 3 weeks (P < .05). STA showed higher bone-to-implant contact ratio (BIC%) in cortical bone than RBM at 3 and 6 weeks (P < .05). Compared with RBM, SLA-1 had better RTV at 6 weeks and higher BIC% in cortical bone at 12 weeks (P < .05). CONCLUSION: In vivo, compared with SLA-2 and RBM, the implant with the strontium-oxide layer displayed slight advantages in new bone formation and osseointegration in the early healing stage. In the later osseointegration stage, the results of SLA-Sr were comparable with other implants.

The two-dimensional size of peri-implant soft tissue in the anterior maxilla and some relevance: A 1- to 7-year cross-sectional study.

AIM: This study measured the two-dimensional size of soft and hard tissues and analysed some relevance between them. MATERIAL AND METHODS: Ninety-six maxillary anterior implants with a follow-up time 1-7 years postoperatively were evaluated. We superimposed the CBCT data of 72 patients with the optical scan data, followed by the measurements of the thickness and the height of soft and bone tissues. The shoulder of the implant was the reference point for all vertical measurements. RESULTS: At the level of implant shoulder, the mid-buccal mean thickness of soft tissue was 1.83 ± 0.76 mm, and on the palatal side, it was 4.00 ± 1.22 mm. The mean height of mid-buccal and mid-palatal gingiva was 4.16 ± 1.07 mm and 4.27 ± 1.07 mm. The buccal and palatal vertical bone wall peak was 0.41 ± 0.73 mm and 0.22 ± 0.57 mm coronal to the implant shoulder, and the marginal bone loss was -0.28 ± 0.76 mm and -0.84 ± 1.41 mm. Correlation analysis showed that the soft tissue thickness was negatively correlated with the bone thickness at 0 mm on the buccal side and at 0/2/4 mm on the palatal side apical towards from implant shoulder. The gingival height was significantly positively correlated with bone peak height and marginal bone height. CONCLUSION: Soft and hard tissues were basically negatively correlated in the horizontal direction. Sites with little marginal bone loss or high bone peak positively correlated with higher soft tissue levels.

Strontium-incorporated titanium implant surface treated by hydrothermal reactions promotes early bone osseointegration in osteoporotic rabbits.

OBJECTIVES: The aim of the present study was to investigate the effects of strontium-modified implant surfaces on promoting early bone osseointegration in osteoporotic rabbits. MATERIALS AND METHODS: The surface topographies, chemical elements, contact angles and ionic releases of the SLA and SLA-Sr samples were analysed by special instruments separately. Sixteen ovariectomized New Zealand rabbits received glucocorticoid administration, and sixteen SHAM rabbits were used as controls. After generating a successful osteoporosis-induced model, SLA and SLA-Sr implants were randomly inserted into the tibia and femur metaphysis of each animal. The rabbits were sacrificed after 3 and 6 weeks of bone healing, and then, removal torque values (RTVs), percentage of bone area (BA%) and percentage of bone-to-implant contact (BIC%) were analysed for the SLA-Sr and SLA implants. RESULTS: Multiple nanostructures were found on the Sr-incorporated titanium surface, and appropriate amounts of strontium ions from the SLA-Sr surface were released into the surrounding tissue within 21 days. In vivo, SLA-Sr implants displayed much more new bone around their surfaces than the SLA implants. Significantly higher RTVs and BIC% were observed for the SLA-Sr implants than for the SLA implants in both osteoporotic (p < 0.01) and healthy animals (p < 0.01) at 3 and 6 weeks. The SLA-Sr implants exhibited higher BA% in cortical bone (p < 0.01) and in cancellous bone (p < 0.05) than the SLA implants in osteoporotic rabbits at 3 weeks. CONCLUSIONS: It is suggested that Sr-incorporated surfaces treated through hydrothermal reactions have positive effects on promoting early osseointegration in both osteoporotic and non-osteoporotic rabbits.

The effects of Sr-incorporated micro/nano rough titanium surface on rBMSC migration and osteogenic differentiation for rapid osteointegration.

Recruitment of endogenous bone marrow-derived mesenchymal stem cells (BMSCs) has been widely discussed as an alternative strategy for bone regeneration. Strontium (Sr) is known to direct the BMSCs' commitment to the bone lineage and encourage bone formation; however, the underlying mechanisms remain elusive. In this study, an Sr-incorporated micro/nano rough titanium surface (MNT-Sr) was fabricated by hydrothermal treatment in an attempt to facilitate BMSCs' recruitment and their osteogenic differentiation to enhance rapid osseointegration. Micro rough titanium (MT) was set as the control biomaterial. In vitro, MNT-Sr and its extracts promoted the migration and osteogenic differentiation of BMSCs. In animal studies, green fluorescent protein (GFP)-labeled BMSCs were intravenously injected into wild-type rats for tracing before tibial implantation surgery. The GFP+BMSC recruitment to the implantation site was successfully triggered by MNT-Sr implantation. A trend for increased bone area (BA%), bone-implant contact (BIC%) and removal torque values (RTVs) was observed for the MNT-Sr implant compared to that observed for MT at 2 weeks. Advanced mechanism analysis indicated that Sr2+ enhanced the SDF-1α/CXCR4 signaling pathway both in vitro and in vivo. Taken together, these findings suggest that MNT-Sr has promising therapeutic potential for future use in dental implants by homing endogenous stem cells to stimulate bone regeneration.

A retrospective study of 30,959 implants: Risk factors associated with early and late implant loss.

AIM: This retrospective study assessed the risk factors associated with early and late implant loss at the patient- and implant-based analysis. MATERIALS AND METHODS: A total of 18,199 patients received 30,959 dental implants during the years 2011-2015. Age, gender, jaw, location, implant brands, implant length and diameter, bone augmentation procedures, and the number of implants placed per patient were recorded. A multivariate generalized estimating equation (GEE) logistic regression was used to identify risk factors related to both early and late implant loss. RESULTS: The cumulative survival rates were 98.0% for patients and 98.7% for implants after 1-6 years observation time. A total of 183 patients with 194 implants were lost before or at the abutment connection, and 193 patients with 209 implants were lost after occlusal loading of the implant fixture. The multivariable GEE logistic regression showed that males, patients aged ≥41 years, and mandibular anterior location were risk factors for early implant loss. In the case of late implant loss, males, patients aged ≥41 years, bone augmentation and short implants were correlated with a significantly increased failure rate. CONCLUSIONS: General factors such as male sex, elderly patients, mandibular anterior location, bone augmentation and short implants were associated with implant loss.