Microimplants Brochure
ver. 20080925
Clinical Advice
   
Postoperative patient management  
There is little to report about noticeable pain or side effect like infection after microimplant placement. Antibiotics prescription is not necessary with microimplant installation without incision. Also analgesics or NSAIDs is not necessary since microimplant of small diameter rarely induces pain or swelling. However patients should be told to revisit the clinic when feeling pain during mastication. This kind of pain is usually derived from microimplant contact with root. If it is diagnosed to be root contact, one should move teeth away from microimplant. If only slight mobility is felt, retighten the microimplant instead of removing it. Although patients seldom need any medication, doctors should make prescriptions of antibiotics and other pain medications available for them on a needed basis. Microimplant sites require excellent oral hygiene with soft brushing and possibly water irrigation. From time to time chemotherapeutic rinses may ward off any inflammation and infection. Also patients should be warned not to touch microimplant by their fingers and chopsticks etc.
 
Explanation for possibility of failure  
Microimplant has a failure rate of 5~25% depending on the operaters’ technique, patient type and insertion sites. Usually more failures occur in mandible than maxilla. The patients should be fully aware with the possibility of failure before starting microimplant treatment.
 
Avoiding root damage  
The proximity of microimplants to the roots of teeth present orthodontists with an important challenge. They must use extreme care to avoid roots when positioning the microimplant. Serial periapical Xrays taken by tube shift technique can help determine if adequate space exists for the implant between teeth. CT scans offer 3-D images for precise interpretation (Fig.1), but this brings up the issues of radiation exposure and extra expense. To date, root damage has not presented many problems. Roots typically demonstrate good recuperative power, even when severely challenged as it happens during apicoectomies. The day after placing microimplant, patients will complain of a dull pain during mastication, if a microimplant comes in contact with a root, moving the root away from the implant will usually relieve patient discomfort. However, occasionally there are no adverse signs and symptoms whilst the root comes in contact with the microimplant, by virtue of their own movement. Thus, a diagonal path of microimplant insertion will help to avoid root injury when placing the microimplant between roots. If there is not enough inter-radicular space, the roots can be moved apart orthodontically before placing the implants (Fig.2).
fig 1
Fig. 1 Review root approximation by microimplant with a conventional radiographs or CT scans.
 
fig 2
Fig. 2 If the space between the roots is very narrow, the microimplant can be placed after making adequate space by moving the roots. If the wall of the maxillary sinus is very low, also, space can be made first and then the microimplant can be placed in a more perpendicular direction rather than in an oblique direction.
 
Orthodontic Force application  
Theoretically, we have to wait 2-3 months for osseointegration between titanium surface and bone tissue. Also, it is better to wait about 2 weeks for soft tissue healing before applying orthodontic force when we do use stab incision for implantation. However, when we attempt distraction osteogenesis (DO), we do not wait for osseointegration between screw pin and bone before force application. Similarly we can commence immediate loading after implantation, if needed. Actually, there were no clinical differences in failure rates between immediate loading and delayed loading the applied the force was kept to less than 300gm. It can be inferred that the mechanical stability is far more important than osseointegration in microimplant anchorage systems. Light continual forces as generated by nickel titanium coils are more favored over chain elastomerics that often have excessive initial forces.
 
Microimplant removal  
Fortunately, strong osseointegration does not occur between titanium alloy microimplant and bone, and this simplifies the removal of the microimplant. In the open method, a clinician can easily remove the microimplant by engaging the microimplant head with the driver and turn it in the opposite direction of the insertion. What is more, local needle-stick anesthesia is not needed during this procedure. Patients may have some minor discomfort when the implant irritates the soft tissue during its removal, but this gives far less discomfort than an anesthetic needle-prick. Topical anesthesia is enough if you want to avoid any pain during removal of microimplant. In the closed method, small incision is made over the head portion of microimplant to expose it after local anesthesia. The initial turn, sometimes does offers some resistance, so, use caution with the first turn so as not to fracture the microimplant.
fig 3
Fig. 3 Removal of microimplant (AbsoAnchor , Dentos Inc.) using hand driver on the buccal surface of maxilla (upper row) and the palate (lower row). There is no need of needle-stick anesthesia for its removal. Only a topical anesthesia is recommended.
 
fig 4
Fig. 4 Removal of microimplant using a speed reduction engine driver on the palatal surface without needle-stick anesthesia (above). Hand-Driven contraangle drive is also very useful to remove the microimplant (below).