When Your Sinus Gets in the Way of Successful Implant Placement

When Your Sinus Gets in the Way of Successful Dental Implant Placement

Successful placement of implants in the posterior maxilla could potentially be compromised by the lack of vertical dimension between the alveolar crest and the floor of the maxillary sinus. Typically, 10mm of vertical bone is required for predictable implant success (Misch 1987) although success can be achieved with less than 20 mm (Fugazzoto 2007). Moreover, bone density in the posterior maxilla is often poor, which could lead to complications during implant fixation. To address these problems, maxillary sinus elevation surgery was developed to increase the amount of bone available for implant placement.

Lateral Window Sinus Lift: A Sinus Augmentation Technique

Implant placement can be performed simultaneously with the sinus elevation procedure or following a healing period that can last

6-9 months. Immediate placement during sinus elevation reduces overall healing time and eliminates another surgical procedure, which can be desirable to patients. The decision to place an implant during sinus augmentation is dependent on the presence of adequate bone volume and quality to provide for initial stability of the implant. Rosen and colleagues (1999) recommended at least 5mm of native bone for immediate implant placement during sinus augmentation. However, more recent studies have found that implant stability can be achieved with less than 5mm (Peleg 2006).

Lateral Window Sinus Augmentation: The lateral approach involves a modified Caldwell-Luc operation to gain access to the sinus cavity. A bony window is created in the lateral maxillary wall, the Schneiderian membrane is elevated, and bone grafting material is a combination of autogenous bone and allograft. An absorbable collagen membrane is placed between the bone graft and the membrane as well as over the bony window.

This technique is usually the preferred method of sinus elevation in situations of poor bone quality and minimal residual bone height because it allows for direct visualization and accurate bone placement and volume at the position of the implant. Also, tearing of the membrane can be easily treated, minimizing contamination of the graft during healing.

For more information about Sinus Augmentation (Lift) procedures or Dental Implant Procedures, contact Joseph R. Nemeth, DDS and Associates at 248.357.3100 or via email at jodi@drnemeth.com. You may also want to visit the practice website at http://www.drnemeth.com.

Ridge Modification Prior to Dental Implant Placement

The American Academy of Periodontology (AAP)
http://www.perio.org/

The AAP Reports:

Deformities in the upper or lower jaw can leave you with inadequate bone in which to place dental implants. This defect may have been caused by periodontal disease, wearing dentures, developmental defects, injury or trauma. Not only does this deformity cause problems in placing the implant, it can also cause an unattractive indentation in the jaw line near the missing teeth that may be difficult to clean and maintain.

To correct the problem, the gum is lifted away from the ridge to expose the bony defect. The defect is then filled with bone or bone substitute to build up the ridge. Your periodontist can tell you about your options for graft materials, which can help to regenerate lost bone and tissue.

Finally, the incision is closed and healing is allowed to take place. Depending on your individual needs, the bone usually will be allowed to develop for about four to 12 months before implants can be placed. In some cases, the implant can be placed at the same time the ridge is modified.
Ridge modification has been shown to greatly improve appearance and increase your chances for successful implants that can last for years to come. Ridge modification can enhance your restorative success both esthetically and functionally.

To learn more about Michigan dental implants, call Joseph R. Nemeth, DDS and Associates at 248.357.3100 or visit us on the web at http://www.drnemeth.com/. You can also visit the AAP website at http://www.perio.org/.

Michigan Dental Implant Impression Comparisons

Taking an impression is the first step in producing a model to indicate the positioning of Michigan dental implants and/or abutments in a patient's mouth. A device which facilitates the replication of implant positions on the study models is called and impression coping and is often required during the impression stage of placing dental implants.

Impressions may be taken in one of two ways: at the implant level or at the abutment level. Placement of an implant analog, a device which mimics the implant on the study model, must occur during an implant-level impression, while abutment level impressions require placement of an abutment analog or a device which mimics the abutment.

Which impression technique is used depends on the preference of the restorative dentist and also varies by implant system. With nonfriction implant systems, impressions can be taken at either the implant or abutment level. With internal friction abutments, delivery of the abutment to its final position is necessary before the final impression is taken.

Comparison of Implant-Level and Abutment-Level

	Implant-Level Impressions	Abutment-Level Impression
Ease of localization	Requires subgingival placement of copings	Easier, because margins are often supragingival
Impression copings	Necessary	Conventional impression without copings is available in some cases
Abutment selection and preparation	On a model in the laboratory	Can be done in the mouth, chairside
Abutment modification	Not needed once delivered	May be needed in the mouth
Custom abutment	Available	Not available (unless an implant-level impression was taken first).
Interim and final crown fabrication	Can be performed in the laboratory, together with the abutment selection and preparation	Chairside relines of provisional restorations and final impressions often necessary

*Source: http://online.lexi.com

Implant-level Impressions

Implant-level impressions are similar for any type of prosthesis. There are two main types of impression copings – closed tray and open tray. Closed tray or transfer impression copings remain on the implant complex after the impression is removed and need to be placed into the impression manually. Open tray or pickup impression copings are automatically retained in the impression after removal. This usually requires the manipulation of a long screw that is not present in transfer copings.

For more information on implant impression comparison, call (248) 357-3100 and talk to an implant specialist. If you're a general dentist who would like to see a demonstration of taking implant impressions in the Oakland, Wayne, or Macomb County Michigan area, feel free to contact Joseph Nemeth, DDS & Associates by phone or email jrn@drnemeth.com. Also look for us on the web at www.drnemeth.com.