Osseointegrated Implants Part 2 Flashcards
Fully Bone Anchored ProsthesisWhat is it?
The fully bone anchored prosthesis is connected to supporting fixtures through the transmucosal components, the abutments either in the maxilla/mandible. To provide proper support for a fully bone anchored prosthesis a minimum of four to six fixtures are necessary. Ideally a fifteen millimeter length/longer should be placed when there is adequate bone. If bone density and quality is poor, the number of fixtures should be increased.
What’s design, advantage and disadvantage of Fully Bone Anchored Prosthesis (Fig. 22.3)?
Design
Fully bone anchored prosthesis does not obturate the space between the prosthesis and residual tissues.
Implant Analog
An analog is something that is analogous or similar to something else. Implant analog is used in the fabrication of the master cast to replicate the retentive portion of the implant body or abutment. After the master impression is secured the corresponding analog (implant body, abutment for screw or other portion) is attached to the transfer coping and the assembly is poured in stone to fabricate the master cast.
Advantages
- Satisfies functional demands.
- Greater psychological acceptance.
Disadvantages
- Airflow pattern produced during speech is unimpeded, which may present problems for the patient if their occupation requires good speaking ability.
- In case of severe resorption in the maxilla esthetic results may be difficult due to added amount of anatomical structures.
- It may be difficult to obtain lip support.
What’s over denture?
Implant supported overdenture is a treatment of choice in case of soft/hard tissue defects, Esthetics can be improved by increasing or decreasing the amount of denture base material. This change in design can enhance lip and facial support. Overdenture is attached to supporting fixtures using various connectors or attachments, which usually do not alter esthetic results. Minimum of two fixtures are needed for support.
What’s advantage and dis advantage of over denture?
Advantages
- Implants for overdenture may be used as secondary retention in patients with poor bone quality and quantity that may have been inadequate to support a fully bone anchored prosthesis.
- Problems related to functional speech disturbances and esthetic soft tissue support could be eliminated.
- It is the treatment of choice for handicapped patients or patients lacking manual dexterity for intricate hygiene procedures needed for the fully bone anchored prosthesis.
- Use of fewer implants can be considered a financial advantage if cost is of concern to the patient.
- It can be used as interim prosthesis if it has to be converted to a fully bone anchored prosthesis.
- Hygiene maintenance is less complicated.
Disadvantages
- It may not satisfy patients with negative attitude towards removable prosthesis.
- Some overdentures may be bulky especially in a patient who has lost larger amounts of hard and soft supporting tissue since the denture base material is increased to compensate this loss.
What’s radiography stent? What is it used for? Where is it placed? The equation?
A diagnostic template incorporating stainless steel balls is used for treatment planning of the implant position. A panoramic radiograph is made with template seated in the mouth to evaluate vertical bone height in relation to the mental foramen and inferior alveolar nerve in the mandible (Fig. 22.5). In the maxilla the vertical bone between the floor of maxillary sinus-alveolar crest and
FIGURE 22.5: Radiographic view
nasal floor-alveolar crest is evaluated. The actual diameter and position of the stainless steel balls in the template relative to the diameter and the position measured on the radiograph help determine distortion of size and position as seen on the radiographs.
A D(real) = A (OPG) (real) D (OPG)
What are two methods of resin fabrication?
There are two methods for fabrication of a resin splint. One method involves duplication of the patient’s present prosthesis and using the duplicate as both a radiographic and surgical splint. The other method involves fabrication of a resin denture from study casts.
What’s surgical template and its two stages?
Surgical Template (Fig. 22.7)
As mentioned in radiographic splint, surgical template can be fabricated by duplicating the existing denture or a newly fabricated prosthesis.
FIGURE 22.9: Procedure for implant placement
FIGURE 22.7: Surgical stent
A. Nobel Biocare implant.
The following case demonstrates the placement of Branemark implant (Figs 22.8 and 22.9).
Second Stage Surgery
The uncovering of the implant is carried out after a healing phase of at least 4 months. The gingival former is screwed onto the implant and the flap sutured around it (Fig. 22.10).
How do we take impressions after soft tissue is healed?
Impressions can be made after the soft tissues have healed – approximately two weeks. The transfer coping is inserted into the implant and the abutment screw tightened. The transfer coping transfers the exact position of the implant to the model through the impression. The two types of impression techniques are: (a) transfer technique and (b) pickup technique.
What’s transfer technique?
Once the gingiva is healed, the gingiva former is unscrewed and replaced with indirect transfer coping. The head of the screw should be covered with wax and the impression is made. Laboratory analogs are placed in the impression in relation to the impression coping and the cast is poured. The abutment is screwed on to the fixture (Fig. 22.11).
What’s pick up impression technique 4 steps
An alternative method is to use an open tray. In this case the direct transfer coping is secured in place with a guide pin. Once the impression material has set, the guide pin is loosened. The transfer coping remains in the impression when it is removed from the mouth (Fig. 22.12).
FIGURE 22.12: (A) Impression coping with guide pin (B) Impression tray (C), (D) Impression material
Base plate wax is adapted around the replicas and guide pins are screwed into the replica (Fig. 22.13).
After application of tinfoil, substitute, autopolymerizing resin is adapted (Fig. 22.14) to the master cast such that the material engages undercuts in the gold cylinders. The interface between the brass replica and gold cylinder is opened for visualization on the facial surfaces.
FIGURE 22.14: Record base fabrication
Base plate/modeling wax are used to fabricate the occlusion rim (Fig. 22.15) in the usual fashion. Wax occlusion rims are used to establish maxillomandibular relations followed by trial of the waxed up (Fig. 22.16) denture and final denture insertion (Fig. 22.17).
