top of page
borndatosibupwels

Implant 3d Crackl : comment créer des modèles osseux en 3D et calculer la densité osseuse



Pick and Place. The [Implant Library] window as shown in Fig. 72 provides the user with a Manufacturers list, a Product Lines list, a Preview window and a section where the individuals implant models are to be selected from.




Implant 3d Crackl




Place. To place an implant fixture, click on the area where the virtual implant is to be placed and select the corresponding tooth number when the dialog below pops up. The default tooth numbering system can be changed in the [Preference] menu when needed.


Bone Density Graph. This tool provides graphs on the bone density information for each implant. This information is displayed in two viewing directions: Coronal-Apical (the two graphs on the top) and the Implant Perpendicular direction (the lower graph). Click [Bone Density] graph from [Implant Task Tools] and choose the ID of the implant in question.


Users will be able to see bone density information of both the inside and outside of the implant fixture. [Thickness] refers to the thickness of the shell around the implant that is used to gather bone density values. Any changes made to the implant while the [Bone Density Graph] is still open will be immediately registered and updated on the graph.


List. This tool provides information on all of the currently placed implants including implant ID, apical/coronal diameters, and the length of each implant. [Show], [Hide], [Remove] or [Locate] all from this window.


Reference. The point where the two blue lines cross is called the [Reference] point, and this is what is shown in the [CrossSectional] pane. For a closer look, users can first choose [Reference] from [Task Tools] and then click wherever they need. It is recommended to use this tool before an implant fixture is placed.


As can be seen below, the [Preferences] menu has three tabs: [View], [Settings], and [Color]. In the default [View] tab, users will be able to set preferences for whether they want to be able to see hash lines, nerve segments, implant safety cylinders, etc.


To access [Verification] for specific implants, the user can click on an implant first on the [Dental] tab and then click on the [Verification] tab or simply right-click on an implant and select [Verification]. For more than one implants, users can switch between them using the implant ID on the provided toolbar located above the four panes, as shown below.


The icon shown in Fig.103 refers to the reorientation of implants.The user will be able to see four arrows surrounding the selected implant, and two arrows outside for precise rotations in the [Implant Parallel] pane. The distance the implant is moved in each direction by one click, and degrees the implant is rotated by one click can all be set using the settings. Any changes made can also be reversed using the icons. The [Verification] tab has only two task tools:


Since the discipline of maxillofacial surgery, in particular, has undergone a remarkable rate of technological innovation associated with computer assistance in the last two decades [11], patient-specific implants designed and manufactured using computer-aided design (CAD) and computer-aided manufacturing (CAM) have become a highly clinically relevant part in routine and complex individual surgical cases [12,13]. Based on a computer tomography scan (CT) or cone beam computer tomography scan (CBCT) of the patient, implants can be virtually designed using CAD software [14] and consecutively manufactured. Those services are usually clinic-externally supplied by subtractive manufacturing like milling or by additive manufacturing (AM) like powder bed fusion [7]. In contrast to AM, the cost- and material-intensive subtractive process employs milling of the 3D model from a material block in a computer numerical controlled (CNC) milling machine. Furthermore, the freedom of implant design for successful milling is limited [7].


Optimal flowability, displayed by the melt flow rate (MFR), was determined by the evaluation of commercial filament technical data sheets [19]. The optimal MFR for material extrusion was evaluated between 5 g/10 min and 50 g/10 min. The implant requirement of the mechanical toughness and the mechanical stiffness were investigated for different polymers in previous works of Katschnig et al. [7,20]. The main results suggested a composite of a rigid and stiff polymer and a soft and tough polymer. This material hybrid delivered a synergy effect in mechanical tests, especially in the non-linear increase in the impact energy [7]. These findings can result in a stiff and at the same time tough implant. These data are given in Table 1. The bioactivity of PETG and TPU was also examined by Katschnig [7] and is given in Table 2. Moreover, the positive cell-impact of polyurethane polymers was proposed by J.A. de La Peña-Salcedo et al. [21]. Following these preliminary works, the final material choice fell on the (hard) thermoplastic polyethylene terephthalate glycol (PETG) as base polymer and the (soft) thermoplastic elastomer polyurethane (TPU) as bioactive polymer. The PETG Mimesis DP300 was supplied by Selenis (Selenis S.A, Portalegre Portugal) and the TPU Polyflex TPU95 was purchased from Polymaker (Polymaker BV, Shanghai, China).


This selection promoted the idea of using TPU outer layers (soft shell) as crack stoppers for PETG-filled (stiff core) implants in the maxillofacial area. At the same time, a TPU shell could have a cell-activating effect. The potential combination of enhanced mechanical performance and bioactive shell forms the potential biofunctionality of the fabricated implant. Extrusion-based AM opens the possibility of producing these biofunctional hybrids in one process step by dual printing.


A first bone defect (implant A) was created in the anatomical area of the right mandibular angle (approx. 3.0 cm 2.0 cm 1.0 cm), including the right oblique line, cortical bone and the infra-alveolar nerve, as it often occurs after the resection of neoplastic processes that infiltrate the bone. The aim was to digitally scan the defect and the previously resected defect positive. The aim was to achieve the subsequent surgical filling of the defect with a printed replication of the defect positive.


An upright orientation in the build room was chosen to minimize the support structures and at the same time sufficiently stabilize the implant during printing. In addition, care was taken to ensure that the layer orientations correspond as far as possible to the principal stress directions in a biaxial stress state of the implant. For dual printing, a primetower was also printed. The tower ensures that the nozzle is filled after the tool change. Figure 2 shows the sliced implants including orientation in the build room, layer orientation and the material sections of PETG and TPU.


The sliced and orientated maxillofacial implant A [7]; (A): standard implant; (B): standard implant cut at Z = 5 mm and enlarged; (C): performance implant with TPU shell (green) and PETG core (blue); (D): performance implant cut at Z = 5 mm and enlarged; additionally shown in 3: the prime tower to the left of the implant.


Results of the single print: Picture (A) shows the outside of implant B, picture (B) the inside. Picture (C) [7] shows the outside of implant A, picture (D) [7] the inside (with porous inner bone structure).


Results of the dual print: picture (A) shows the outside of implant B, picture (B) the inside; picture (C) [7] shows the outside of implant A, picture (D) [7] the inside (with porous inner bone structure).


For simplification, only the standard implants were manually embedded in an associated bone model and checked for easy insertion, smooth transitions to the bone, good adaptation to the skull surface contour and the correct distance to the bone margins. The assembly capability was defined by the screwability with surgical fixatives and the holding power of the fixation. Figure 6 shows the results.


Clinic-internal assembly of the maxillofacial standard implants A [7] and B with a mandibular mini plate system from Medartis AG. The self-tapping screws were 5 to 7 mm long. (A): lesion A (lateral); (B): lesion B (lateral); (C): inserted implant A (lateral); (D): inserted implant B (lateral); (E): mounted implant A (lateral); (F): mounted implant B (lateral); (G): inserted implants A and B (frontal); (H): mounted implants A and B (frontal).


A clean and complete extrusion process could be carried out for both the standard and performance implants. The optimized printing parameters derived from [7] could be confirmed. In dual printing, the adhesion between the TPU shell and the PETG core seems to be good. The surfaces are homogeneous and have a process-specific resolution (0.1 mm [26]). The exceptions were slightly frayed areas on the supported surfaces of the performance implants, which had to be smoothed in post-processing. The reason for the surface damage was probably the good adhesion between the PETG support and the TPU shell, if the defined offsets of 0.3 mm are bypassed by extrusion errors. TPU is known for its increased adhesiveness [27], so if there is any offset bridging of extruded material, the contact adhesion tends to be strong. In addition, slight traces of overheating in the TPU shell were found. The reason for this may have been a local overheating by tool path-enforced low layer times (


The assembly ability of implant A and B was clinically proven in a printed ex-vivo bone model. Figure 7 shows a qualitative comparison between an already published result of fitted and mounted PEEK implants that are conventionally available for a clinical use and a fitted and mounted PETG implant A. One can see that the clinical fixation with osteosynthesis microplates and screws possibly does not harm the implants and leads to aesthetically good results. Furthermore, the implant fits to the three-dimensional bone contour. 2ff7e9595c


0 views0 comments

Recent Posts

See All

Comments


bottom of page