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Ridge Augmentation

Dr. Neale asks:

I am presently treatment planning ridge augmentation to replace teeth #29 & 30. I plan to use allograft Puro.

My question involves placement of two stage dental implants at the same visit or to play it safe and do the graft and let heal, then go back and do the dental implants in 4 months.

Ridge height is adquate for 10mm length dental implants, however ridge widgth is inadequate. Provided inital stabilization is present, would this be considered too risky if approximtately 50% of the facial threads are exposed after osteotomy and dental implant placement? Am I asking too much from a grafting point of view to cover these threads should this amount of dental implant be exposed?

January 30, 2006 in Techniques and Procedures | Permalink | Comments (51)

Preparing the Abutment

Dr. Aaron asks:

For some of my more apprehensive dental implant referrals I place the solid abutment onto the dental implant for them, allowing them to take a conventional crown and bridge impression for the crown. 

I usually prepare the abutment outside the mouth, then try it in the mouth until I am satisfied with the occlusal clearance/countouring.  My question is: Instead of preparing the solid abutment outside the mouth, can I prep the abutment while it is attached to the dental implant?  I have seen it done routinely in books and journals, but I am unfamiliar with the technical considerations and/or things to avoid. Thanks for any help.

January 30, 2006 in Techniques and Procedures | Permalink | Comments (17)

Dental Implant Contraindications

Dr. Nimchuk asks:

This week I have had three patients who have come in for consultations for dental implant placements but who are on bisphosphonates (Fosamax) for the treatment of osteoporosis.

Because of the potential for developing osteonecrosis of the jaws, oral surgery procedures are contraindicated in these cases.  This means no extractions or dental implants. 

Going off the drug will not make them better candidates for dental implants because the effects of bisphosphonates lasts for years.  These drugs seem to be prescribed almost routinely for women over age 60 if there is any suspicion of osteoporosis.  Right now there are quite a few class action lawsuits where persons on bisphosponates have had complications.  Does anyone have any  experience with this dilemma or a protocol for managing these patients?

January 30, 2006 in Treatment Planning & Complications | Permalink | Comments (46)

Effects of Electromagnetic Field

Dr. Stefan asks:
I found little information about tissue regeneration around  dental implants under the action of a electromagnetic field.

However, it would seem that electromagnetic fields can  positively influence  tissue regeneration around dental implants. I am looking for any information or a clinic, university or lab (and a partner) where I can perform studies regarding the influence of electromagnetic fields on dental implants. Please post any information. Thanks.

January 29, 2006 in Techniques and Procedures | Permalink | Comments (3)

Dental Implant after Extraction

I have reviewed an implant patient just recently, where I placed an implant immediately after extracting his upper  left first molar. Unfortunately he has experienced some recession around the dental implant. Whilst no thread is exposed, the head of the dental implant is visible before taking off the healing cap. The implant is very firm and would be ready to crown.

What techniques are there, if any, to crown this tooth? Has anyone had an abutment made to fit over the top and sides of the dental implant before? Can I achieve a reasonable result, or is it better to have the implant removed and redo this case? Does anyone have any ideas?

January 23, 2006 in Treatment Planning & Complications | Permalink | Comments (26)

Dental Implants for Dentures

Linda, a dental implant patient, asks us:
Does anyone experience any problems with dental implants used to hold lower dentures firmly in place? 

Are they supposed to be sensitive to cold air or cold foods?  What should one do when one has a problem with these types of dental implants, even years down the road?  Thanks.

January 23, 2006 in Treatment Planning & Complications | Permalink | Comments (4)

Metal Reinforced Acrylic Frameworks

For fixed full-arch dental implant supported partial dentures in the mandible, one approach has been to use metal reinforced acrylic frameworks.

The advantage to this design is that the metal reinforcement provides strength and the acrylic – pink and white – is easy to repair. Are many of you using this approach? What kinds of problems have you encountered? How is patient acceptance?

January 23, 2006 in Techniques and Procedures | Permalink | Comments (5)

TGF-Beta Signaling

What are your thoughts on the recent finding, released only last month,  that the quality of bone matrix, a key component of bone, is regulated by a molecule known as transforming growth factor beta or TGF-Beta? The research may lead to improvements in the quality and speed of bone repair following dental implant placement or bone grafting.

For those who did not get a chance to read about the study, below is a brief sypnosis:

The ability of bone to resist damage depends on the mass, or quantity, of bone, its architecture and the quality of bone matrix, the mineralized material between cells. Several molecular factors have been shown to regulate the mass and architecture of bone. So far, however, none have been shown to regulate bone matrix, which is responsible for bone elasticity and toughness. There has been significant disagreement about whether the quality of bone matrix varies among individuals and, if it does, whether it could be altered for therapeutic reasons. In any case, until now, scientists have lacked a strategy for measuring its quality and teasing out its impact, says senior study author Tamara Alliston, PhD, UCSF assistant adjunct professor of Cell and Tissue Biology.

In the current study, the team explored whether transforming growth factor beta (TGF-ß) regulates the properties of bone matrix because there were hints that it might. TGF-ß is known to play a role in the development of osteoblasts, cells that produce bone matrix.

The researchers carried out their evaluation in five sets of mice genetically engineered to produce differing levels of TGF-ß signaling within osteoblasts, and, for comparison, in normal, or 'wild type' mice. After the animals had been euthanized, the team utilized highly sensitive instruments developed in the materials sciences -- atomic-force microscopy, x-ray tomography and micro-Raman spectroscopy -- to measure the properties of bone matrix independent of bone mass and architecture. They also compared the bones' resistance to fracture in a bending test.

The results were notable, according to Alliston. In animals genetically engineered to produce high levels of TGF-ß, the measurements of bone matrix indicated increased susceptibility to fracture. The matrix was less elastic, less hard and contained lower levels of the mineral calcium phosphate. In addition, the animals' bones were less resistant to fracture in the bending test.

In contrast, in animals with low levels of TGF-ß the bone matrix was more elastic, harder, had higher mineral concentration and the bone overall had increased mass. In addition, the bones were more resistant to fracture in the bending test.

The bones studied included the femur, tibia and calvarial parietal bones.

"This is the first evidence that properties of bone matrix can be regulated by a growth factor and that by modifying the TGF-ß pathway, specifically, these properties can be controlled," says Alliston.

The study suggests, she says, that TGF-ß could be targeted for clinical intervention in patients. "By decreasing TGF-ß signaling at the relevant site in the body, we may be able to improve the quality of bone to either prevent the damage that occurs in osteoarthritis and osteoporosis, or improve the quality and speed of bone repair following bone fracture, joint implantation, dental implants or bone grafting."


"If we could decrease the production of TGF-ß at the site of the transplant, we might be able to strengthen the quality of bone being formed," says the lead author of the study, Guive Balooch, BA, in the UCSF Graduate Program in Oral and Craniofacial Sciences and Division of Bioengineering.

Source: http://pub.ucsf.edu/newsservices/releases/200512136/

January 17, 2006 in Dental Implant News | Permalink | Comments (1)

Single Maxillary Central Incisor

I think replacing a single maxillary central incisor is quite challenging.

In positioning the dental implant fixture I try to orient so that the center of the long axis passes through a point about 2mm lingual to where the incisal edge of the natural tooth should have been.  I position the fixture about 2mm lingual to the adjacent central and lateral.  I am using Atlantis abutments and cement retained crowns.  What are others doing differently or better?

January 17, 2006 in Techniques and Procedures | Permalink | Comments (6)

Filling the Screw Channel

I have heard a number of speakers recommend different materials for filling  the screw channel before cementing a crown or bridge.

I have heard of gutta-percha, cotton, Cavit, vinyl polysiloxane, etc.  What are most of you using?  What problems have you had?  Has anybody had problems seating the crown after filling the screw channel?

January 17, 2006 in Techniques and Procedures | Permalink | Comments (9)