Exploiting the Transformation Temperature to Reform an Infolded Nitinol Self-Expanding Peripheral Stent

Purpose: Nickel-titanium (nitinol) alloys possess a special set of properties that allow for a wide range of applications. Specifically, the transformation temperature for self-expanding nitinol peripheral stents allows for easy crimping at or below room temperature and reformation at body temperature becoming superelastic. Case Report: We report the case of an elderly man with iliac stenting 1 month prior, who presented several weeks after recovering from coronavirus disease 2019 with recurrent anterior-wall ST-elevation myocardial infarction. This was complicated by deformation and infolding of the previously implanted nitinol self-expanding stent in his right common iliac artery (CIA). Understanding nitinol’s specific properties, we proceeded with rapid injections of iced saline to cool the nitinol stent to its transformation temperature while nudging the distal end of the stent with a partially inflated balloon. This maneuver softened the nitinol stent, allowing us to “unfold” and reappose it against the wall of the right CIA, resulting in successful restoration of the original shape of the nitinol self-expanding stent. Conclusion: This represents the first reported case describing treatment of an infolded nitinol self-expanding peripheral stent by exploiting the transformation temperature of nitinol using iced cold saline to successfully restore the stent’s original shape and structure.

Penatalaksanaan non-bedah kasus previously initiated therapy gigi molar pertama maksila dengan lesi periapikal dan konfigurasi dua saluran akar mesiobukal Non-surgical management of previously initiated therapy of the maxillary first molar with periapical lesions and two mesiobuccal canals configuration

ABSTRAKPendahuluan: Penatalaksanaan kasus penyakit pulpa yang disertai dengan lesi periapikal dapat dilakukan dengan perawatan saluran akar tanpa intervensi bedah. Preparasi biomekanis pada perawatan endodontik non-bedah dapat mengeliminasi bakteri dari saluran akar dan mencegah terjadinya infeksi berulang setelah dilakukannya obturasi. Kompleksitas anatomi menyebabkan keterbatasan preparasi biomekanis saluran akar, sehingga perawatan dapat mengalami kegagalan. Variasi anatomi saluran akar pada gigi molar pertama rahang atas umumnya terdapat pada bagian palatal akar mesiobukal yang disebut sebagai saluran akar mesiobukal kedua dengan insidensi 94%. Saluran akar mesiobukal kedua berukuran lebih sempit dan dangkal dibandingkan saluran akar mesiobukal pertama, sehingga dibutuhkan beberapa metode untuk menentukan lokasi orifis tersebut. Tujuan laporan kasus ini adalah membahas mengenai penatalaksanaan non-bedah gigi pasca perawatan endodontik parsial yang disertai dengan lesi periapikal. Laporan kasus: Pasien perempuan berusia 28 tahun datang dengan keluhan gigi belakang kiri atas sakit berdenyut sejak 1 bulan, gigi tersebut pernah dirawat saluran akarnya beberapa tahun sebelumnya. Pemeriksaan klinis menunjukkan terdapat tambalan permanen pada gigi 26. Pemeriksaan radiografis menunjukkan adanya gambaran radiopak pada email mesio-oklusal hingga mencapai dasar kamar pulpa, pelebaran ligamen periodontal, terputusnya lamina dura, serta lesi periapikal pada akar mesial dan palatal. Preparasi akses dilakukan pada gigi 26, dilanjutkan dengan penentuan lokasi orifis mesiobukal kedua. Empat saluran akar dipreparasi menggunakan instrumen rotary nickel titanium dengan teknik crown down dan dilakukan obturasi teknik kondensasi lateral. Restorasi definitif berupa mahkota penuh porselen. Simpulan: Lesi periapikal sembuh setelah dilakukan preparasi pada saluran akar mesiobukal kedua sehingga pengetahuan mengenai anatomi dan variasi internal saluran akar gigi sangat penting dalam keberhasilan perawatan endodontik non-bedah.Kata kunci: Perawatan endodontik non-bedah; previously initiated therapy; lesi periapical; mesiobukal kedua ABSTRACTIntroduction: The management of pulp disease cases accompanied by periapical lesions can be done by root canal treatment without surgical intervention. Biomechanical preparations for non-surgical endodontic treatment can eliminate bacteria from the root canal and prevent re-infection after obturation. However, the complexity of the anatomy limits the biomechanical preparation of the root canal so that treatment can fail. Anatomical variations of the root canal in the maxillary first molars are generally found in the palatal part of the mesiobuccal root, which is the second mesiobuccal root canal with an incidence of 94%. The second mesiobuccal root canal is narrower and shallower than the first mesiobuccal root canal, so several methods are needed to determine the location of the orifice. The purpose of this case report was to discuss the non-surgical management of teeth after partial endodontic treatment accompanied by periapical lesions. Case report: A 28-year-old female patient complained of throbbing pain in the left upper back tooth for one month. The tooth had had its root canal treated several years before. Clinical examination revealed permanent fillings on tooth 26. Radiographic examination showed the radiopaque appearance of mesio-occlusal enamel to the floor of the pulp chamber, widening of the periodontal ligament, rupture of the lamina dura, and periapical lesions of the mesial and palatal roots. Access preparation was performed on tooth 26, followed by the determination of the location of the second mesiobuccal orifice. Four root canals were prepared using a rotary nickel titanium instrument with a crown down technique and obturation with lateral condensation technique. The definitive restoration is a full porcelain crown. Conclusions: Periapical lesions healed after preparation of the second mesiobuccal root canal. This result proves that knowledge of the anatomy and internal variations of the root canal is fundamental in the success of non-surgical endodontic treatment.Keywords: Non-surgical endodontic treatment; previously initiated therapy; periapical lesions; second mesiobuccal canal

The analysis of research methods and results on resistance of nickel-titanium endodontic instruments to torsion load: the systematic review

Relevance. The objective of this study was to analyze current data concerning research methods and results on resistance of nickel-titanium endodontic instruments to torsion load in order to minimize complications of dental root canal treatment. The use of the nickel -titanium endodontic instruments is a special importance to ensure high-quality dental root canal treatment; it prevents the further contamination of the canals with microorganisms. However, these instruments can form a fracture under torsional load which leads to further complications.Aim. The analysis of research methods and results on resistance of nickel-titanium endodontic instruments to torsion load for minimization complications.Materials and methods. A series of publications in the electronic databases such as Google Scholar, Pub Med was analyzed in the course of a systematic review of the literature. The articles dealing with nickel-titanium endodontic instruments and torsion load that directly influences the quality of dental root canal treatment were included in the paper.Results. 73 articles were viewed during the review. Having analyzed the literature for inclusion criteria, the total number of publications has become 51. There were 16 main methods which demonstrated the influence of torsion load on endodontic instruments. These methods were summarized in the Table 1.Conclusions. As regards literature data, there are a various number of methods which converge to one conclusion: nickel-titanium instruments cannot fully resist torsion load. Fracture is caused approximately in 0,5-5% of cases.

A Critical Appraisal of the Use and Properties of Nickel–Titanium Dental Alloys

Nickel–titanium (NiTi) archwires are used in dentistry for orthodontic treatment. NiTi alloys have favourable mechanical characteristics, such as superelasticity and shape memory, and are also known as a corrosion-resistant alloy. In specific cases, an archwire could be attacked by certain types of corrosion or wear degradation, which can cause the leaching of metal ions and a hypersensitive response due to increased concentrations of Ni in the human body. A systematic search of the literature retrieved 102 relevant studies. The review paper focuses on three main fields: (i) electrochemical properties of NiTi wires and the effect of different environments on the properties of NiTi wires (fluoride and low pH); (ii) tribocorrosion, a combination of chemical and mechanical wear of the material, and (iii) the biocompatibility of NiTi alloy and its subsequent effect on the human body. The review showed that corrosion properties are affected by microstructure, pH of saliva and the presence of fluorides. A high variation in published results should be, therefore, interpreted with care. The release of nickel ions was assessed using the same unit, showing that the vast majority of metal ions were released in the first few days of exposure, then a stable, steady state was reached. In tribocorrosion studies, the increased concentrations of Ni ions were reported.

An Update on Nickel-Titanium Rotary Instruments in Endodontics: Mechanical Characteristics, Testing and Future Perspective—An Overview

Since the introduction of Nickel-Titanium alloy as the material of choice for the manufacturing of endodontic rotary instruments, the success rate of the root canal therapies has been significantly increased. This success mainly arises from the properties of the Nickel-Titanium alloy: the biocompatibility, the superelasticity and the shape memory effect. Those characteristics have led to a reduction in time of endodontic treatments, a simplification of instrumentation procedures and an increase of predictability and effectiveness of endodontic treatments. Nevertheless, the intracanal separation of Nickel-Titanium rotary instruments is still a major concern of endodontists, with a consequent possible reduction in the outcome rate. As thoroughly demonstrated, the two main causes of intracanal separation of endodontic instruments are the cyclic fatigue and the torsional loads. As results, in order to reduce the percentage of intracanal separation research and manufacturers have been focused on the parameters that directly or indirectly influence mechanical properties of endodontic rotary instruments. This review describes the current state of the art regarding the Nickel-Titanium alloy in endodontics, the mechanical behavior of endodontic rotary instruments and the relative stresses acting on them during intracanal instrumentation, highlighting the limitation of the current literature.

Effect of Autoclaving Cycles on the Cyclic Fatigue Resistance of Race and Race Evo Nickel-Titanium Endodontic Rotary Files: An In Vitro Study

Objective: The aim of this study was to evaluate the influence of autoclave sterilization on the resistance to cyclic fatigue of two nickel-titanium (NiTi) endodontic files of identical design and taper, but with different NiTi alloy treatments: the newly introduced heat-treated Race Evo and the electropolished Race files. Materials and methods: Fifteen Race (25/0.06) files and fifteen Race Evo (25/0.06) files (n = 30 in total) were randomly assigned to five sub-groups each consisting of three files of the same NiTi alloy treatment. One group served as a control with files unautoclaved. The four remaining groups were sterilized in a steam sterilizer for 1, 3, 5, and 10 autoclave cycles, respectively. Files then underwent cyclic fatigue testing in a simulated metal canal block. A scanning electron microscope was used to inspect the surface of the fractured instruments. Statistical analysis was conducted using independent t-test and multi-factorial analysis of variance with significance set at a p value of ≤0.05. Results: Both Race Evo and Race files showed no significant difference between the different autoclaving cycles in terms of the number of cycles to fracture (p = 0.232 and p = 0.359). Despite rotating at a higher speed, the number of cycles to fracture of heat-treated Race Evo files was significantly higher than that of Race files (p ≤ 0.0001). Conclusion: Autoclave sterilization has no significant effect on the resistance to cyclic fatigue of heat-treated Race Evo or electropolished Race files. However, Race Evo files showed superior resistance to cyclic fatigue irrespective of autoclaving cycles.

Pediatric Rotary Files: Evolution to Revolution

The main goal of pulp therapy in primary dentition is to preserve the primary tooth thus protecting future normal occlusion. Routinely, pulp debridement and canal shaping are done by manual H-files, K-files, Broach, etc. Manual instrumentation may be time- consuming, thus impacting the behaviour of the child negatively. Thus arises the need for alternate instrumentation which will reduce the time required for treatment with better treatment outcomes. In 1988, Walia et al. introduced Nickel-Titanium (Ni-Ti), which revolutionized the discipline of Endodontics. These Ni-Ti files have advantage of shape memory and super elasticity thus improving the canal preparation and resulting in better shaped canals. In 2002, for first time Barr et al reported the use of rotary Ni-Ti files for the therapeutic purpose during Pulpectomy procedure in pediatric patient. He observed better acceptance by pediatric patient and good quality obturation. Till 2016, pulpectomy procedures were accomplished by the combination of hand files and adult rotary files. Adult rotary files are designed according to the morphology for permanent teeth and adult jaw size, thus the use of adult rotary files are in primary teeth may result in lateral perforation due to softer dentine of roots of primary teeth and may cause discomfort to the child thus making child unco-operative. But in 2016, Ganesh et al., pioneered the specialization of Paediatric Endodontics with his invention of specially designed rotary files. Their shape was specially designated for application in tortuous canals of primary teeth. Presently, a variety of pediatric rotary files like Kedo-STM (India), Pro AF Baby GoldTM (India),PrimePedoTM (India), DXL-ProPedoTM (India), NeolixTM (France),Denco® Kids files (China) and, Sani® Kid rotary files (China). This review is an album of these newer files and clinical and in-vitro research on them.