Vitamin E Phosphate Coating Stimulates Bone Deposition in Implant-related Infections in a Rat Model.

BACKGROUND: Implant-related infections are associated with impaired bone healing and osseointegration. In vitro antiadhesive and antibacterial properties and in vivo antiinflammatory effects protecting against bone loss of various formulations of vitamin E have been demonstrated in animal models. However, to the best of our knowledge, no in vivo studies have demonstrated the synergistic activity of vitamin E in preventing bacterial adhesion to orthopaedic implants, thus supporting the bone-implant integration. QUESTIONS/PURPOSES: The purpose of this study was to test whether a vitamin E phosphate coating on titanium implants may be able to reduce (1) the bacterial colonization of prosthetic implants and (2) bone resorption and osteomyelitis in a rat model of Staphylococcus aureus-induced implant-related infection. METHODS: Twelve rats were bilaterally injected in the femurs with S aureus UAMS-1-Xen40 and implanted with uncoated or vitamin E phosphate-coated titanium Kirschner wires without local or systemic antibiotic prophylaxis. Eight rats represented the uninfected control group. A few hours after surgery, two control and three infected animals died as a result of unexpected complications. With the remaining rats, we assessed the presence of bacterial contamination with qualitative bioluminescence imaging and Gram-positive staining and with quantitative bacterial count. Bone changes in terms of resorption and osteomyelitis were quantitatively analyzed through micro-CT (bone mineral density) and semiquantitatively through histologic scoring systems. RESULTS: Six weeks after implantation, we found only a mild decrease in bacterial count in coated versus uncoated implants (Ti versus controls: mean difference [MD], -3.705; 95% confidence interval [CI], -4.416 to -2.994; p < 0.001; TiVE versus controls: MD, -3.063; 95% CI, -3.672 to -2.454; p < 0.001), whereas micro-CT analysis showed a higher bone mineral density at the knee and femoral metaphysis in the vitamin E-treated group compared with uncoated implants (knee joint: MD, -11.88; 95% CI, -16.100 to -7.664; p < 0.001 and femoral metaphysis: MD, -19.87; 95% CI, -28.82 to -10.93; p < 0.001). We found decreased osteonecrosis (difference between medians, 1.5; 95% CI, 1-2; p < 0.002) in the infected group receiving the vitamin E-coated nails compared with the uncoated nails. CONCLUSIONS: These preliminary findings indicate that vitamin E phosphate implant coatings can exert a protective effect on bone deposition in a highly contaminated animal model of implant-related infection. CLINICAL RELEVANCE: The use of vitamin E coatings may open new perspectives for developing coatings that can limit septic loosening of infected implants with bacterial contamination. However, a deeper insight into the mechanism of action and the local release of vitamin E as a coating for orthopaedic implants is required to be used in clinics in the near future. Although this study cannot support the antimicrobial properties of vitamin E, promising results were obtained for bone-implant osseointegration. These preliminary results will require further in vivo investigations to optimize the host response in the presence of antibiotic prophylaxis.

Antibiofilm activity of sandblasted and laser-modified titanium against microorganisms isolated from peri-implantitis lesions.

Infections due to biofilm-producing microorganisms are one of the main causes for the failure of dental implants. Increasing efforts have been made in order to develop new strategies to prevent biofilm formation. In this study, the biofilm development on a newly designed laser-modified titanium implant surface was evaluated and compared to that on conventional sandblasted titanium used in implant dentistry. The amount of biofilm produced by Staphylococcus aureus, Pseudomonas aeruginosa and Porphyromonas gingivalis isolated from peri-implantitis was assessed by a semi-quantitative spectrophotometric method and by confocal laser scanning microscopy. Results showed a lower biofilm production on laser-modified surface compared to the sandblasted one. In particular, a significantly lower total volume of the biomass was observed on laser-modified surface, while no significant changes in live/dead bacteria percentages were noticed between materials. Modifying the topography of the conventional implant surface with laser ablation could represent a promising approach for inhibiting biofilm formation.

Magnifying loupes versus surgical microscope in endodontic surgery: a four-year retrospective study.

The purpose of this retrospective study was to evaluate the 4-year outcome of endodontic microsurgery using two different magnification devices. One-hundred and two teeth in 65 patients were included according to specific selection criteria. Endodontic surgery was performed under surgical microscope as magnification device in 63 teeth in 36 patients, while 39 teeth in 29 patients were treated under magnifying loupes. Thirteen patients did not attend the 4-year follow up. The overall success rate on a patient basis was 91.7% at the 1-year and 90.5% at the 4-year follow up for the group using loupes, while for the group using microscope it was 91.4% at the 1-year and 93.3% at the 4-year follow up. The relative risk was 2.07 (95% confidence interval: 0.31, 13.95) in favour of the group in which microscope was used. No statistically significant difference was found in the treatment outcomes relating to the type of magnification device.

Antimicrobial activity of pure platelet-rich plasma against microorganisms isolated from oral cavity.

BACKGROUND: Autologous platelet concentrates (PCs) have been extensively used in a variety of medical fields to promote soft and hard tissue regeneration. The significance behind their use lies in the abundance of growth factors in platelets α-granules that promotes wound healing. In addition, antibacterial properties of PCs against various bacteria have been recently pointed out. In this study, the antimicrobial effect of pure platelet-rich plasma (P-PRP) was evaluated against oral cavity microorganisms such as Enterococcus faecalis, Candida albicans, Streptococcus agalactiae, Streptococcus oralis and Pseudomonas aeruginosa. Blood samples were obtained from 17 patients who underwent oral surgery procedures involving the use of P-PRP. The antibacterial activity of P-PRP, evaluated as the minimum inhibitory concentration (MIC), was determined through the microdilution twofold serial method. RESULTS: P-PRP inhibited the growth of Enterococcus faecalis, Candida albicans, Streptococcus agalactiae and Streptococcus oralis, but not of Pseudomonas aeruginosa strains. CONCLUSIONS: P-PRP is a potentially useful substance in the fight against postoperative infections. This might represent a valuable property in adjunct to the enhancement of tissue regeneration.

Treatment of through-and-through bone lesion using autologous growth factors and xenogeneic bone graft: a case report.

BACKGROUND: This pilot case study aimed at evaluating the possibility of achieving optimal hard and soft tissue regeneration using plasma rich in growth factors (PRGF) and anorganic bovine bone (ABB) for the surgical treatment of a large through-and-through periapical bone lesion. CASE REPORT: Maxillary incisors of a patient with through-and-through periapical lesion of endodontic origin were treated using modern endodontic surgical technique with the adjunct of PRGF. The PRGF clot was positioned over the palatal side of the lesion while the remaining bone defect was grafted with PRGF and ABB. A collagen membrane embedded with plasma very rich in growth factors covered the graft. Post-operative pain and swelling were negligible, and soft tissue healing was very fast. One-year clinical and radiographic outcome showed complete healing and functionality. DISCUSSION: The addition of PRGF to ABB could improve the regenerative process, reducing postoperative symptoms and resulting in a fast and predictable hard and soft tissue healing.

Investigation on the shaping ability of nickel-titanium files when used with a reciprocating motion.

INTRODUCTION: The introduction of nickel-titanium (NiTi) files into clinical practice has improved the quality of canal shaping, but increasing the curvature of the root canal (or the diameter of the master instrument that prepares the full working length) could result in more transportation, straightening, and aberration of the canal. Nickel-titanium instruments are significantly safer and have an extended cyclic fatigue life when used with a reciprocating movement. The purpose of this study was to compare the shaping ability of FlexMaster NiTi instruments when used in either continuous or reciprocating movements. METHODS: Thirty-two Endo Training Blocks ISO 15, 2% taper, 10-mm radius of curvature, and 70° angle of curvature were prepared, according to the group, with FlexMaster NiTi instruments either in continuous rotation or in reciprocating (60° clockwise, 40° counterclockwise) movement. Preoperative and postoperative images of the simulated canals were taken under standardized conditions. The preoperative and postoperative images were combined exactly. The amount of resin removed was determined both for the inner (convex) and the outer (concave) sides of the curvature at 10 different points. RESULTS: In the most apical third of the canal, the Continuous group produced the largest enlargement of the canal as compared with the Reciprocating group (P < .05). In the apical third, the Continuous group displayed significantly greater enlargement of the canal at the external side. CONCLUSIONS: The shaping of simulated canals is more centered by using a reciprocating motion when compared with continuous rotation, but the reciprocating motion could be more time-consuming.

Effect of guided tissue regeneration on the outcome of surgical endodontic treatment of through-and-through lesions: a retrospective study at 4-year follow-up.

PURPOSE: The main purpose of this retrospective cohort study was to evaluate the 4-year success rate of endodontic surgery in combination with a collagen resorbable membrane for the treatment of through-and-through periradicular lesions. MATERIALS AND METHODS: Patients with one or more teeth with a through-and-through periradicular lesion in need of endodontic surgery were treated. A clinical and radiographic evaluation was performed at 3, 6, 12, 24, 36, and 48 months. The outcome was categorized at 1 and 4-year follow-up as success, failure, and doubtful depending on clinical signs and symptoms and radiographic evaluation. Fisher's exact test was used to evaluate differences between successful and failed cases (P < 0.05). RESULTS: Forty-three teeth in 33 patients were radiographically and clinically evaluated after 4 years. Thirty-eight teeth were classified as success, 4 teeth as failure, and 1 tooth as doubtful. No statistically significant differences were found in results related to tooth type, tooth location, and presence of post. CONCLUSIONS: The association of endodontic surgery and guided tissue regeneration for the treatment of through-and-through periapical lesions leads to excellent outcomes up to 4 years. Standardized criteria are needed to determine the treatment outcome.

Scanning electron microscopic analysis of the integrity of the root-end surface after root-end management using a piezoelectric device: a cadaveric study.

INTRODUCTION: The introduction of piezoelectric instruments in endodontic surgery allowed clinicians to manage the bone tissue with precision reducing the risk of damaging soft tissues. Although such instruments can also be used to prepare root-end cavity, few information is available on the effect of piezosurgery on dentine. This cadaveric study investigated the integrity of root apices after root-end cavity preparation by piezoelectric instruments at different device settings. METHODS: Fifty maxillary anterior teeth underwent endodontic treatment and apical resection in situ. Ten teeth were used as control. Retrograde cavities were prepared in 40 teeth (10 per group). In three groups, the piezoelectric device was set at constant vibration mode (CV), and three power levels were used. In another experimental group (n = 10), vibration + pulsation mode (VP) was selected, and low power was used. Each root was duplicated and analyzed by scanning electron microscopy for the presence of cracks and marginal chipping. RESULTS: The number of cracks was significantly higher in the VP group, whereas no significant difference was found among CV groups. No difference between groups was found for crack type. The VP group showed a significantly poorer quality of cavity margin respect to the CV groups. CONCLUSION: Constant vibration mode is recommended for retrograde preparation with piezosurgery.