Intentional Replantation of a Second Premolar with Internal Resorption and Root Fracture: A Case Report.

AIM: This case aims to detail intentional replantation as a last resort to save an otherwise hopeless premolar with perforated internal resorption and root fracture. BACKGROUND: Internal root resorption, progressive destruction of intraradicular dentin, is a condition that sometimes renders a tooth non-restorable. In the rare cases reported where severe internal resorption leads to root fracture, extraction of the tooth seemed to be a common treatment of choice, and a few literatures had reported endodontic surgery as an alternative treatment option. To date, there had been no report of treating internal root resorption using intentional replantation. CASE DESCRIPTION: A 20-year-old male presented swelling at the buccal region of his left maxillary second premolar (#13). Clinical examination revealed a sinus tract and fractured dens evaginatus at the occlusal surface of the tooth. Radiographically, a large area of radiolucency was detected within the middle third of the root, where root fracture was present, leaving a triangular-shaped mature root apex. The condition was diagnosed as internal root resorption and root fracture. Endodontic surgery was excluded from treatment choices due to potential damage of periodontal bone. Instead, intentional replantation was performed, with the application of biomaterials including mineral trioxide aggregate (MTA) and platelet-rich fibrin (L-PRF). The tooth achieved satisfactory healing and remained asymptomatic after 2 years of follow-up. CONCLUSION: The successful outcome of the case suggests that intentional replantation could preserve a fractured tooth caused by internal root resorption. Incorporated application of biomaterials, such as MTA and L-PRF, might as well improve the chances of saving this otherwise hopeless tooth. CLINICAL SIGNIFICANCE: Through careful planning and execution, intentional replantation is a viable alternative treatment option to preserve a fractured tooth caused by internal root resorption, while leaving periodontal bone architecture almost intact. How to cite this article: Yang Y, Zhang B, Huang C, et al. Intentional Replantation of a Second Premolar with Internal Resorption and Root Fracture: A Case Report. J Contemp Dent Pract 2021;22(5):562-567.

Controlled Delivery of Growth Factor by Hierarchical Nanostructured Core-Shell Nanofibers for the Efficient Repair of Critical-Sized Rat Calvarial Defect.

Electrospun nanofibers have received much attention as bone tissue-engineered scaffolds for their capacity to mimic the structure of natural extracellular matrix (ECM). Most studies have reproduced nanofibers with smooth surface for tissue engineering. This is quite different from the triple-helical nanotopography of natural collagen nanofibrils. In this study, hierarchical nanostructures were coated on the surface of drug-loaded core-shell nanofibers to mimic natural collagen nanofibrils. The nanoshish-kebab (SK) structure was decorated regularly on the surface of the nanofibers, and the inner-loaded bone morphogenetic protein 2 (BMP2) exhibited a gentle release pattern, similar to a zero-order release pattern in kinetics. The in vitro study also showed that the SK structure could accelerate cell proliferation, attachment, and osteogenic differentiation. Four groups of scaffolds were implanted in vivo to repair critical-sized rat calvarial defects: (1) PCL/PVA (control); (2) SK-PCL/PVA; (3) PCL/PVA-BMP2; and (4) SK-PCL/PVA-BMP2. Much more bone was formed in the SK-PCL/PVA group (24.57 ± 3.81%) than in the control group (1.21 ± 0.23%). The BMP2-loaded core-shell nanofibers with nanopatterned structure (SK-PCL/PVA-BMP2) displayed the best repair efficacy (76.38 ± 4.13%), followed by the PCL/PVA-BMP2 group (39.86 ± 5.74%). It was believed that the hierarchical nanostructured core-shell nanofibers could promote osteogeneration and that the SK structure showed synergistic ability with nanofiber-loaded BMP2 in vivo for bone regeneration. Thus, this BMP2-loaded core-shell nanofiber scaffold with hierarchical nanostructure holds great potential for bone tissue engineering applications.

[Expert consensus on biomechanical research of dental implant].

Current biomechanical research of dental implants focuses on the mechanical damage and enhancement mechanism of the implant-abutment interface as well as how to obtain better mechanical strength and longer fatigue life of dental implants. The mechanical properties of implants can be comprehensively evaluated by strain gauge analysis, photo elastic stress analysis, digital image correlation, finite element analysis, implant bone bonding strength test, and measurement of mechanical properties. Finite element analysis is the most common method for evaluating stress distribution in dental implants, and static pressure and fatigue tests are commonly used in mechanical strength test. This article reviews biomechanical research methods and evaluation indices of dental implants. Results provide methodology guidelines in the field of biomechanics by introducing principles, ranges of application, advantages, and limitations, thereby benefitting researchers in selecting suitable methods. The influencing factors of the experimental results are presented and discussed to provide implant design ideas for researchers.

Ultrasound: a potential technique to improve osseointegration of dental implants.

Dental implants have been widely used in clinic for the restoration of lost teeth in recent decades, but there still remains a great challenge for even a higher success rate and a shorter rehabilitation time. The osseointegration between dental implant and alveolar bone tissue is crucial for a successful implantation. Ultrasound has been proved to be an effective treatment for bone fracture healing. The underlying mechanism of the mechanotransduction pathway involved in cellular responses to ultrasound is still not clear, however, numerous studies have confirmed its ability to enhance osteogenesis and therefore facilitate bone regeneration. In this paper, we hypothesize that this kind of wave might have an ability to strengthen and accelerate osseointegration of dental implants, and thus a potential usage in dental therapy.