Does implant placement using a minimally invasive technique increase early failures among trainees at an academic center?

PURPOSE: This study aims to identify whether dental implants placed using a flapless technique have a higher early failure rate, defined as failure within 6 months of placement, compared to implants placed with flap elevation when a surgical guide is not used. METHODS: A retrospective cohort study was conducted to evaluate implants placed with either flapless (FL) or mucoperiosteal flap (MF) surgery between 2006 and 2012 at the Philadelphia VA Medical Center (PVAMC). Implant status after FL or MF surgery was assessed using dental encounter and radiographs at subsequent follow-up appointments to assess for early implant failures within 6 months of implant placement. RESULTS: The FL technique was used to place 89 implants in 38 subjects, while the MF technique was used to place 381 implants in 139 subjects. Early failure occurred in 37 implants, of which 13 occurred in the FL group and 24 occurred in the MF group. FL surgery was found to be associated with a 265% increase in early implant failure (OR 2.653; 95% CL 1.287-5.469) and was statistically significant (p = 0.0064). Residents were over 200% more likely to have an early implant failure when using the FL technique (OR 2.314; 95% CL 1.112-4.816), CONCLUSIONS: Analysis revealed flapless implant placement was associated with higher early implant failure rates. In addition, early failures were more likely to occur when residents placed an implant using the flapless technique. While FL surgery can result in long-term success, it is a more technique-sensitive approach that requires greater clinical skill and stricter case selection to perform.

Low Insertional Torque and Early Dental Implant Failure.

PURPOSE: There is lack of uniformity regarding the ideal insertional torque with which dental implants need to be placed. The purpose of this retrospective analysis is to compare the incidence of early dental implant failures with an insertional torque less than 30 N-cm to implants placed with an insertional torque 30 N-cm or greater. METHODS: A retrospective cohort study was conducted to evaluate dental implants placed between 2015 and 2016 at the Veterans Affairs North Texas Health Care System in Dallas. The primary predictor variable was dental implant insertional torque, measured at the time of implant placement as either greater than or equal to 30 N-cm or less than 30 N-cm. The primary outcome variable was early implant failure, defined as implant exfoliation noted by the patient or failure due to implant movement or pain necessitating explantation before prosthesis loading. The study conducted a time-to-event analysis to examine a group difference in time to implant failure between insertional torque group greater than or equal to 30 N-cm and less than 30 N-cm using Kaplan-Meir curves and a frailty model. The time to follow-up was censored at 6 months. RESULTS: One hundred three patients had 214 implants placed, with early failures occurring in 14 implants (6.5%). Implants placed with an insertional torque less than 30 N-cm were nearly 14 times more likely to have an early failure compared to implants placed with an insertional torque 30 N-cm or greater (hazard ratio = 13.909; 95% confidence interval, 1.835 to 105.416), which was statistically significant (P = .0108). CONCLUSIONS: The results of this retrospective cohort study suggest that insertional torque values less than 30 N-cm are associated with early dental implant failures. Future, prospective studies will be performed to further elucidate the association between insertional torque and early dental implant failure.

Effect of dose and release rate of CTGF and TGFß3 on avascular meniscus healing.

Meniscus tears in the avascular region rarely functionally heal due to poor intrinsic healing capacity, frequently resulting in tear propagation, followed by meniscus deterioration. Recently, we have reported that time-controlled application of connective tissue growth factor (CTGF) and transforming tissue growth factor ß3 (TGFß3) significantly improved healing of avascular meniscus tears by inducing recruitment and step-wise fibrocartilaginous differentiation of mesenchymal stem/progenitor cells (MSCs). In this study, we investigated effects of the dose of CTGF and the release rate of TGFß3 on avascular meniscus healing in our existing explant model. Our hypothesis was that dose and release rate of CTGF and TGFß3 are contributing factors for functional outcome in avascular meniscus healing by stem cell recruitment. Low (100 ng/ml) and high (1,000 ng/ml) doses of CTGF as well as fast (0.46 ± 0.2 ng/day) and slow (0.29 ± 0.1 ng/day) release rates of TGFß3 were applied to our established meniscus explant model for meniscus tears in the inner-third avascular region. The release rate of TGFß3 was controlled by varying compositions of poly(lactic-co-glycolic acids) (PLGA) microspheres. The meniscus explants were then cultured for 8 weeks on top of mesenchymal stem/progenitor cells (MSCs). Among the tested combinations, we found that a high CTGF dose and slow TGFß3 release are most effective for integrated healing of avascular meniscus, demonstrating improvements in alignment of collagen fibers, fibrocartilaginous matrix elaboration and mechanical properties. This study may represent an important step toward the development of a regenerative therapy to improve healing of avascular meniscus tears by stem cell recruitment. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1555-1562, 2019.

Engineered Healing of Avascular Meniscus Tears by Stem Cell Recruitment.

Meniscus injuries are extremely common with approximately one million patients undergoing surgical treatment annually in the U.S. alone. Upon injury, the outer zone of the meniscus can be repaired and expected to functionally heal but tears in the inner avascular region are unlikely to heal. To date, no regenerative therapy has been proven successful for consistently promoting healing in inner-zone meniscus tears. Here, we show that controlled applications of connective tissue growth factor (CTGF) and transforming growth factor beta 3 (TGFß3) can induce seamless healing of avascular meniscus tears by inducing recruitment and step-wise differentiation of synovial mesenchymal stem/progenitor cells (syMSCs). A short-term release of CTGF, a selected chemotactic and profibrogenic cue, successfully recruited syMSCs into the incision site and formed an integrated fibrous matrix. Sustain-released TGFß3 then led to a remodeling of the intermediate fibrous matrix into fibrocartilaginous matrix, fully integrating incised meniscal tissues with improved functional properties. Our data may represent a novel clinically relevant strategy to improve healing of avascular meniscus tears by recruiting endogenous stem/progenitor cells.