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Dental implantology has come a long way since its introduction in dentistry. With this there is advancement in the implant abutmnent system as well. There are various implant abutments are also available in the market according to the type of material used , method of fabrication and method of retention….. On the basis of method of retention 2 types of abutment were available- screw retained and cement retained .
Periimplantitis as there is no pdl so the resistance of the gingival tissues to the apically placed cements are minimal
Difficult to retieve
While removing the excess cement there are chances of scratches on the abutment
Ease to acces the post area
Easy retievibility
Easy oral hyegine
Frequent loosening of the screws
Increased cost due to plastic sleeves , lab fixation screws etc…………so as we can see that the procedure is tiring and time taking..thus a new system was introduced which was patented by RHODO SMILOC which is shape memory implant abutment system
These are the parts present- implant abutment and shape memory abutment nitinol
2 sets of flaps-inner and outer……… first inner flaps engage the abutment undercut…so the shape memory locks on the abutment…after that the outer flaps engage the coping undercuts…ie the prosthesis…. So the prosthesis can be placed using finger pressure. nitinol
For retirieval the device is heated through the lingual access holes by a heated probe which causes all the flaps to disengage….this causes the loss of mechanical undercut and thus the prosthesis can be retieved through the finger pressure………dono fins closed mei retieve karte h….retention ke lie the flaps should be spread.
The shape memory occurs because the sleeve is made up of nitinol-nickel 49% and titanium 51%.. The solid-state phase transformation, also known as the martensitic transformation, is a reversible process in nitinol. As shown in Figure 4 and 5, the parent phase is the austenite (cubic) phase, and the daughter phase is the martensitic (monoclinic) phase. The austenitic phase is the remembered phase as set by heat tempering during the manufacturing process. Upon cooling, there is a phase change to the martensite phase without any physical change in shape. When an external deformation stress is applied, the phase remains as a martensite phase, but because of the ability of the alloy to undergo twinning, the alloy remains in that deformed shape. Twinning is a unique property of the nitinol alloy. The alloy undergoes limited deformation without breaking any atomic bonds, although there is a rearrangement of the ions without any slip…. . The heat transfer from the abutment to biological tissues, the mechanical resistance to displacement, and the fatigue properties and corrosion resistance of the new abutment system have been studied in detail by the authors and will be published in future reports
Tell about the elevation in the top of the abutment
After a six months followup, the crown was removed because it was under trial…. This is the activation device that was used….we can see the 2 tips present that can be used to transfer heat to the abutment through lingual access holes to retieve the crown from the lingual areas
Year 2019 y study to 6 months for 5 additional study participants. During the 6-month observation period, the restoration was held firmly in place, and no patient reported complications or problems occurred during the routine oral care. In addition, the overall health of the peri-implant tissue remained unchanged for the duration of the study.
However this research did not tell about the changes in the abutment during resistance to monotonic crown-removal forces and fatigue during long-term cyclic loading. , this pilot study focused on the assessment of prosthesis seating, fit, retrievability, and hygiene and visual inspection for peri-implant disease in a relatively short-term 6-month observational period. nitinol-containing materials are typically contraindicated for patients who have nickel allergies.to be on a safer side The nitinol sleeve is engineered to have a protective titanium oxide layer to slow down nickel. diffusion, and the retention system has been designed so that the sleeve is not openly exposed to biological fluids. However, it is impossible to eliminate nickel diffusion. Therefore, future investigations should analyze nitinol corrosion resistance and quantify nickel release .also tell about the leakage through the lingual acces hole cement
In 2020 the abutment was approved by fdi and commercialized .
A, Shape-memory alloy retention system. B, Cross-section illustration of mechanically interlocking mechanism used to retain dental prostheses to implant abutments. Shape-memory nitinol alloy sleeve has outer arms that engage coping undercuts and inner arms that engage undercuts on abutment. Heating shape-memory alloy sleeves to 60 C causes instantaneous shape change that causes arms to disengage undercuts
60 year old patient came to the department with loosening of prosthesis .Extraction was done followed by complate denture fabrication..on denture the markers were placed and double scanning technique was used to get the final prosthesis
A, Presurgical maxillary and mandibular implant planning conducted from CBCT images acquired by using dual scan protocol. B, The implant planning by software…. For maxilla conventional implant placement procedure followed by screw retainrd restoration was done
For mandible, implants placed with RODO MU abutments and Smileloc sleeves. B, Interim prostheses retained by shape-memory alloy retention system (mandible) and screw retention (maxilla) delivered with immediate loading. In the mandibular arch, an all-on-4 treatment procedure was also planned, with implants placed perpendicular to the occlusal plane and the use of straight MUA (RODO Medical). The implants were placed in the areas of the mandibular right second molar (CC Parallel RP 5.0 × 11.5 mm, greater than 20 Ncm insertion force; Nobel Biocare), right canine (CC Parallel NP 3.75 × 18 mm, greater than 50 Ncm insertion force), left canine (CC Parallel NP 3.75 × 18 mm, greater than 50 Ncm insertion force), and left second molar (CC Parallel RP 5.0 × 11.5 mm, 20 Ncm insertion force). The posterior implant abutment screws were hand tightened, and the anterior screws were tightened to 35 Ncm. An interim completearch prosthesis retained by the shape-memory alloy retention system (Smileloc; RODO Medical) was delivered
After 3 months, definitive impressions of the implant positions were made by using the open-tray technique. A cobalt-chromium bar and acrylic resin (DuraLay; Reliance Dental Manufacturing) was used to splint the impression copings at the abutment level while making the impressions. Maxillary and mandibular resin framework patteerns were prepared and digitized by using a cast scanner.The scans were used to fabricate the titanium frameworks, which were sent to the laboratory for processing that included laser welding the precision copings
Here we can see the screw access hole sin maxilla na d no holes in the mandible
A shape-memory alloy abutment system was not used for the maxillary complete-arch restoration because of the 45-degree tilt of the posterior implants in the maxilla. The RODO abutments were available with 0-, 17-, and 30-degree angulations at the time of the treatment…. Two methods are used to heat the shape-memory alloy sleeve: originally, an activation probe was inserted into lingual access holes in the crown, which allowed direct contact with the titanium coping, and 15 seconds of contact resistive heating was applied. Recently, an induction removal device (Smilekey; RODO Medical) was FDA-cleared to unlock the shape-memory alloy sleeve by using alternating magnetic fields to heat the nitinol sleeve above its phase-transformation temperature within 5 seconds.
Smile key
Here we can see that the activating unit was different ….it is called the rhodo smile…. Instead of the application of direct contact in the earlier areas the rhodo smile loc usues the induction heating (non contact heating )
After scanning the lab will mill and send the rhodo abutment and the crown
