Questions and Answers

 

After I removed an implant from the packaging, my assistant picked it up without wearing gloves.   Can I still place it into my patient?  Sterile, packaged implants must not be altered in any way.   Touching the implant surface will transfer any foreign materials from that object onto the surface of the implant.   Glove free hands will transfer body oils thereby interfering with osseointegration of the implant.  Glove free hands are also unsterile and will transfer bacteria thereby introducing possible pathogens onto the implant surface.  This in turn can cause an infection around the implant with its subsequent loss.   Many gloves are dusted with talcum powder to ease their placement over the hand.  Talcum will interfere with osseointegration of the implant.   Always use talc free sterile gloves when handling implants.

Do implants fail?  All implants can succeed and all implants can fail.   An implant is considered a failure if the implant fails to knit with the bone (osseointegration) and generally occurs within the first three months.  The main factor in the success or failure of an implant is proper patient selection and careful treatment planning.   It is critical that the clinician have experience in dental implants to ensure success.  Although failure of an implant is disappointing for both the clinician and the patient, the implant can be replaced after a few months of healing should the reason for failure be corrected.

Why does bone shrink back after tooth extraction?  Both jaws are made up of alveolar bone which is bone associated with teeth and basal bone; the part of the mandible and maxilla from which the alveolar process develops.  The main function of alveolar bone is to provide support to teeth.  Once teeth are lost, alveolar bone is no longer stimulated and shrinks back eventually to the basal bone.    It has now been shown that implants brought into physiological function can maintain alveolar bone once teeth are lost.

References

  1. Bone maintenance 5 to 10 years after sinus grafting, Michael S Block, et al, Journal of Oral and Maxillofacial Surgery, Volume 56, Issue 6, June 1998, Pages 706–714

2.    Contemporary Implant Dentistry, 3rd Edition, Carl E. Misch, DDS, MDS, PHD

My patient has an implant that appears loose.  What should I do?   If the abutment is moving, it is not necessarily the implant that is loose.   It could be only the abutment or the attaching screw that is loose.   It is best to send the patient back to the surgeon to check.  The surgeon should take a radiograph, then tighten the abutment or screw into the implant.  If the abutment is loose, the abutment will snug down into the implant with no further movement or rotation.   It is always important to replace the screw with a new one as the screw has probably stretched and has become worn.   If the entire assembly keeps rotating, then indeed it is a loose implant.   Frequently, the loose implant can be spun out with no pain or bleeding.

How do implant supported over dentures differ from conventional dentures?  Conventional dentures rely on suction to function.   Implant supported dentures rely on a mechanical attachment of the prosthesis.   With implant supported over dentures, the teeth may be placed outside the ridge, the posterior teeth can have increased cuspal planes, the hard palate can be eliminated and denture flanges can be reduced from the muscle molded areas.

When using the intra-oral pick-up procedure for attachments in a denture over implants, the denture sometimes appears immovable.   What should I do?   If the acrylic is into an undercut, then the denture is immovable.    Some implants have a flared top in their design allowing an undercut between the abutment and the implant.   In these cases you will need to cut a buccal window into the denture and remove all offending acrylic.  I recommend a parallel sided implant and O ring abutment to eliminate this problem.   Even using O ring abutments and parallel walled implants, the denture may appear too tight to remove.   One trick is to use Vaseline on the abutments prior to placing the O ring and the pick-up.   Another trick is to send the patient to eat a meal, then return.    Usually, that’s all it takes.

Can I use the existing denture or not ?   The original denture may be used if the denture is in good repair, with little or no loss of original vertical dimension and, with the occluding surfaces intact with little wear on the facets.   If the denture is in good repair, a reline will be required as a minimum.   Do not use the original denture but make a new one should the existing denture be in poor repair, with loss of original vertical dimension or  with the occluding surfaces well worn.  When a new opposing denture is being made, do not use the original denture.  As a general rule of thumb:
1.    A denture under 2 years old may be used should it be in good repair.

2.    A denture 2 to 5 years old cannot usually be used.

3.    Do not use a denture over 5 years old.
When should I start the over-denture fabrication: Before surgery:  After surgery and before uncovering or after uncovering?   The restoring clinician can start new over-denture construction at any time but he/she should be aware that bony changes occur continuously during the two years after surgery.    These changes will be partially dependent upon the degree of surgery performed, whether graft material is used, the age and medical condition of the patient.  The biggest changes occur within the first six months with minor changes after the first six months.    Recently it has become popular to, load implants immediately.   You must be aware that immediate overloading  can cause the failure of the implant to integrate.   Great care must be taken to ensure there is minimal loading of the implants especially the first two months after surgery.  If the denture rocks or the abutments appear to be under load, reline the denture to ensure this problem is corrected.  Temporary soft relines should be performed as required.

What procedure should I use to attach the O rings, processing: chair-side pick-up or reline?  Although all techniques are successful, techniques are easier, use less chair-side time and give a better finish to the inside of the denture if you process the attachments into the denture base rather than perform a chair side pick-up.

How can I ensure the patient is ready to have the prosthesis made?   Regardless of whether you are making a new denture over implants for  the first time, doing a chair side O ring pick up or relining the denture, always check the abutments, soft tissue and existing denture before proceeding with any prosthetic restoration.

Ideally, the top of the trans mucosal portion of the O ring abutments should extend no more than 1 mm into the mouth.   Shorter than this may allow the soft tissue to grow over the abutments causing irritation and pain from the entrapped mucosa.   A longer height than 1 mm causes a negative crown/root ratio resulting in unnecessary stress to the bone.   Should the abutments appear too high or too low, have the patient return to the surgeon for assessment and replacement if required.   With the two piece implant and abutment, the surgeon can easily remove and replace the abutment with a longer or shorter one  if required.     The immediate load implant can be adjusted if done so within one or two days of implant placement.

Check the abutments to ascertain any mobility.  There should be no movement from the implant abutments.  If there is any mobility, it probably is due to the abutment being loose in the implant rather than the implant itself.   If so, the abutment will need to be tightened.   If in doubt, refer the patient back to the surgical dentist to assess whether it is only the abutment which is loose or whether the entire implant has lost its integration.   If the abutment is loose, the clinician will be able to tighten the abutment with a hex wrench.

Using a metal mouth mirror, tap the top of the abutments to elicit a “ringing” sound.  The “ringing” sound usually indicates that the implant is integrated with the bone and adds further proof that the implants are sound.  If the tap elicits a dull “muted” sound, this could indicate loss of integration and a connective tissue interface with the bone.   If the implant has lost its integration, the abutment/implant combination will rotate in the bone indicating loss of bony integration.   The implant/abutment combination must be removed.   If the implant is removed, a new implant can be placed after a two month healing period.

Check the mucosa around the abutments for any signs of inflammation.   Ideally, the mucosa around the implant abutment should be attached gingiva rather than unattached and there should be no signs of inflammation.   If there is any inflammation around the abutments, refer the patient back to the surgical dentist to treat and correct.

How long do implants last?  A competent, well trained, experienced dentist should expect osseointegration rates of in excess of 95%.   As a general rule, once an implant has been placed for a year, a patient should expect a 98% success rate over the next four five years.  Dr Bergman has implants still successfully in place after 30 years.

Do implants reject?  There are no recorded cases of rejection of a titanium or HA coated implant.  Implants can become infected however with their subsequent failure.

Does a patient need to be hospitalizedVery few implant placement procedures require hospitalization for the surgery.   With proper surgical technique, the procedure should be no more stressful than a tooth extraction.  Implant placement is generally an in office procedure under local anaesthetic.    Sedation is available for those who wish it on most general practices..

Is the implant placement procedure painful?  Post operative discomfort should be no worse than having a tooth removed.  Most of the post operative symptoms can be drastically reduced by using advanced implant placement technique.

Can I experience improvement immediately?  Yes, healing implants should not be placed under heavy loads during the initial few weeks in order to encourage the bone to ”knit” with the implant.    There are procedures and implants designed especially for “immediate” loading.   An experienced, properly trained dentist will be aware of these implants and procedures.