Dental implant components .pptx

implant

1. Dental implant components and current concepts in implant design   Prepared By: Roshna Talib

2. Components of implant design Diameter of implant The implant diameter is the dimension measured from the peak of the widest thread to the same point on the opposite side of the implant . The diameter of the implant is more important in load distribution as compared to the length of the implant. literatures suggests that at least 3.25 mm implant diameter is required to ensure adequate implant strength and ideal implant diameter is 4 mm in.

3. Implant diameter

4. Components of implant

5. Implant length The implant length is the distance between the implant platform to the apex of the implant. Usually, an implant length of 7 to 13 mm is commonly used. The use of shorter implants is not recommended from a biomechanical point of view because occlusal forces must be dissipated over a larger implant surface area to prevent excessive stresses at the interface.

6. Implant threads Threads are designed to maximize initial contact, enhance the surface area, and facilitate the dissipation of stresses at the bone-implant interface. Implant thread configuration plays an important in the biomechanical optimization of dental implants. Thread shapes in dental implant designs include square, V-shape, and buttress.

7. Basic thread terminology The threads have been incorporated into implants to improve initial stability, enlarge the implant surface area and distribute stress favorably. The major diameter refers to the diameter of implant measured from crest to crest of the opposite sides of the implant. The minor diameter refers to the diameter of implant measured from root to root of the opposite sides of the implant .

8. The angle of the thread refers to the angle of the V-shaped groove made between two threads. Flank is the distance between the crest and the root of a thread. Pitch stands for the number of threads per unit length.

9. Implant collar Usually , implants have been modified by surface treatment, for example, hydroxyapatite (HA) coated implants have an implant collar at the superior aspect of the crest module. This is an important part of the implant as it makes the area of transition of the implant from the bone to the soft tissue.

10. Implant-abutment attachments The part of the implant that gives attachment to the superstructure is known as the implant abutment attachment. There are different types of prosthetic attachment: the external hex, internal hex, and internal taper conical connection (morse taper). (a) External connection. (b) Conical connection from 5 to 6 degrees. (c) Conical connection from 8 to 20 degrees. (d) Internal connection.

11. External hex External hex prosthetic connection was introduced as Bränemark protocol for restoring completely edentulous arches where implants were connected together via a metal bar with a fixed prosthesis. The external hex design was introduced to connect the superstructure to the implant and also as an anti-rotational device to keep the superstructure in its exact place. This external hex, which was only 0.7 mm in height, was not designed to withstand the forces directed on the crowns intraorally. Presently , external hex connections are used widely with more predictable results in implant therapy.

12. Internal hex The internal hex was designed for more stability and strength of the implant-abutment connection. The reasons for this specific internal hex design were the distribution of intraoral forces deeper within the implant to protect the retention screw from excess loading, and to reduce the potential of micro-leakage. This design offers a reduced vertical height platform which helps in the attachment of the prosthetic component. The greater stability of internal hex attachment is due to its longer hex. One major disadvantage is a possible fracture of the thin fixture head. The internal hex connection may be passive fit or friction fit ( morse taper).

13. Passive fit internal hex implants 3-point internal trigon In this design the internal tripod allows abutment to fit only in three possible positions on the implant with a rotation of 120°. The hexagon attachment was preferred over the tripod attachment because of its more degree of freedom of rotation. 6-point internal hexagon attachment In this design, the abutment can be placed at six different positions over the implant with a rotation of 60° which allows a high degree of freedom for abutment placement. Due to long internal screw attachment, the forces are distributed deep into the implant . 12 -point internal hexagon attachment The advantage of this design is the freedom of 30° rotation during placement of the abutment. This is especially useful in case of angled abutments.

14. Internal taper ("morse" taper) In this kind of attachment, a tapered abutment post is inserted into the nonthreaded shaft of a dental implant with the same taper. Here , the abutment is friction seated into the head of the implant fixture. This type of attachment is simple to use and uses no screws, but there is no way to accurately re-seat an abutment. Another problem is the possibility of fixture head fracture.

15. Other implant components Indirect transfer coping (Closed impression) In this impression technique, the transfer coping is screwed into the implant and impression is made with impression material having elastic properties. The coping is not removed from the implant throughout the impression making procedure. Once the impression is set, it is removed from the mouth. Once the impression is out of the mouth, coping is removed from the implant, and is re-oriented and placed back in the impression.

16. Direct transfer coping (Open impression) This technique is used when multiple implants have been placed and many of them or all are oriented in different directions i.e. not parallel to each other. It utilizes a hollow transfer component with a long central screw. Holes are incorporated in the impression tray to allow the long screws to pass through. The screws are accessible to the clinician throughout the impression making procedure projecting out of the impression tray. Once the impression is set, the screws are removed from the abutment transfer coping and impression can be easily removed from the mouth along with transfer coping .

17. Implant abutments Pre-fabricated abutments These are provided by the implant manufacturer companies in various shapes, sizes, and angulations but they cannot be used in each and every case. The use of a prefabricated abutment is contraindicated in Cases with: insufficient interocclusal space Cases where implant requires an angle of correction greater than 150 .

18. Custom Abutments A custom abutment is one which is designed by the practitioner for an individual patient. Custom made abutments are designed when the angulation required is more 15° and relative parallelism is difficult to achieve. The main advantage of this abutment is that the clinician has all the freedom to fabricate the design of abutment according to the restrictions present in a particular patient .

19. Healing abutment A healing abutment is temporarily placed on the implant for a few days to achieve a natural contour of the gingiva. These abutments may be pre- fabricated or customizable healing abutments. Pre-fabricated abutments have a specific shape which cannot be modified by the practitioner. On the other hand, customizable healing abutments are made up of polymer material which allows for easy and quick chair-side modification. After a healing period of 7-10 days, a nicely contoured gingival collar is achieved. After placement of the superstructure, it gives an impression of a natural tooth coming out of gingiva .

20. Temporary abutments These are used for short term and are usually not used in the mouth for longer than 6 months. These are usually made up of polymer material which allows for easy and quick chair-side modification. These are used for screw- or cement-retained temporary crowns or cement- retained temporary bridges.

21. Ball abutments Ball abutments for implant-supported over-denture has traditionally been in the mandible, utilizing two implants for implant-supported over-denture. So , when we place the denture in the mouth, the ball and socket snap-fit with each other and support the denture. The problem with this attachment is that with the passage of time the ball and socket joint become loose and demands a replacement.

22. Locator attachment of implant-supported overdentures In this system, a metal housing which is encapsulated within the prosthesis retains a resilient nylon liner which allows for attachment to the abutment head. The abutments have a self-aligning feature which helps the denture removal by the patient without damage to the nylon component. The nylon liner may be changed after few years, as with due course in time, the attachment may become loose.

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