Craig M. Misch

The repair of localized severe ridge defects for implant placement using mandibular bone grafts.

Severe alveolar deficiencies can prevent ideal implant placement. Management of osseous defects often necessitates autogenous bone grafting. The mandibular symphysis graft technique offers ease of access, good bone quantity for localized repair, a corticocancellous block graft morphology, low morbidity, and minimal graft resorption. An improved bone density results along with a shorter healing time as compared with other methods for bone repair. An understanding of graft management and implant placement is essential for clinical success. (Implant Dent 1995;4:261–267)

A BONE QUALITY-BASED IMPLANT SYSTEM : FIRST YEAR OF PROSTHETIC LOADING

This interim report presents the data from a prospective study of BioHorizons, a bone quality-based implant system, with four implant designs. The surgical survival of 975 implants was 99.4%, with the survival 100% for D4 bone. Three critical phases of crestal bone loss have been identified: bone remodeling from stage I to stage II surgery; stage II uncovery to prosthesis delivery (transition period); and prosthesis delivery up to the first year of loading (early loading bone loss). The stage I to stage II uncovery crestal bone remodeling resulted in a mean vertical bone loss of 0.21 mm to 0.36 mm (SD = 0.90 mm), dependent on whether the implant became exposed in the oral cavity during osseous healing. No statistically significant difference was found among the four implant designs, diameter, bone density, or location. The stage II to prosthesis delivery mean vertical bone loss ranged from 0.12 mm to 0.20 mm. One hundred three consecutive patients (partially and totally edentulous) were restored, with 360 implants and 105 prostheses in function for a period of 12 to 26 months. No early loading implant failure occurred, and all patients with implants are in satisfactory to optimum health according to the Misch Implant Quality Scale. The mean early loading bone loss was 0.29 mm (SD = 0.99 mm). Past clinical reports in the literature indicate most failures or crestal bone loss occur by the first year of loading. This study suggests the bone quality based dental implant design minimizes overall implant failure and crestal bone loss, regardless of bone density.

Use of the Mandibular Ramus as a Donor Site for Onlay Bone Grafting

Cortical bone grafts harvested from the posterior mandible offer several advantages for bone augmentation prior to implant placement. These grafts maintain their dense quality and exhibit minimal resorption upon incorporation. Considerable amounts of bone can be harvested from this area for use as an onlay graft. In addition, the ramus area has some inherent advantages over other donor sites. This article describes the indications and surgical technique for harvesting bone from the ramus region.

Consensus conference panel report: crown-height space guidelines for implant dentistry-part 1.

The International Congress of Oral Implantologists sponsored a consensus conference on the topic of Crown Height Space on June 26–27, 2004 in Las Vegas, Nevada. The panel communicated on several occasions before, during, and after the meeting, both as a group and among individuals. A consensus of one opinion was not developed for most issues. However, general guidelines emerged related to the topic. The following article is Part 2 of a summary of several of the guidelines that should be of benefit to the profession at large. (Part 1 appeared in Implant Dentistry 2005;14:312–321.)

Workshop Guidelines on Immediate Loading in Implant Dentistry

P redictable formation of a direct bone-toimplant interface is a treatment goal in implant dentistry. The 2-stage surgical protocol established by Branemark et al to accomplish osseointegration consisted of several prerequisites, including (1) countersinking the implant below the crestal bone, (2) obtaining and maintaining a soft-tissue covering over the implant for 3 to 6 months, and (3) maintaining a minimally loaded implant environment for 3 to 6 months. The primary reasons cited for the submerged, countersunk, surgical approach to implant placement were (1) to reduce and minimize the risk of bacterial infection, (2) to prevent apical migration of the oral epithelium along the body of the implant, and (3) to minimize the risk of early implant loading during bone remodeling. After this procedure, a second-stage surgery was necessary to uncover these implants and place a prosthetic abutment. Predictable, long-term, clinical rigid fixation has been reported after this protocol in patients who were either completely or partially edentulous. During the past 15 years, several authors have reported that root-form implants may osseointegrate, even though the implants extend above the bone and through the soft tissues during early bone remodeling. This surgical approach has been called a 1-stage or nonsubmerged implant procedure because it eliminates the second-stage implant uncovery surgery. As a result, the discomfort, inconvenience, and appointments of the surgery and suture removal are eliminated. In addition, the soft tissue is more mature before fabricating a final prosthesis.

Maxillary autogenous bone grafting.

Reconstruction of the atrophic maxilla for dental implant placement has many unique considerations. There are several methods available to augment the atrophic maxilla. Of these, autogenous bone grafting offers a well-proven predictable method for ridge augmentation and defect repair for dental implant placement. There are several advantages of using autogenous bone grafts. This article primarily focuses on the use of autogenous onlay bone grafts to reconstruct the atrophic maxilla.

A bone quality-based implant system: a preliminary report of stage I & stage II.

A system is introduced in which dental implants are specifically designed for containment within four different categories of bone densities. The sizes and the textured surfaces that accompany the gradations of lengths and diameters are standardized for each bone type. A modified thread design focuses on compression of bone rather than on shear, and the geometry of the entire implant body reflects features that are concurrent with a “platform effect.” Having been tested by means of finite element analysis and initial animal studies, the results are provided herein for the placement of 364 consecutive implants in five clinical centers on human patients, with surgical survival results of 98.9 percent overall. The initial clinical report of these implants indicates that all bone densities may have similar initial survival rates. (Implant Dent 1998; 7:35–42)

Maxillary Autogenous Bone Grafting

Reconstruction of the atrophic maxilla for dental implant placement has many unique considerations. There are several methods available to augment the atrophic maxilla. Of these, autogenous bone grafting offers a well-proven predictable method for ridge augmentation and defect repair for dental implant placement. There are several advantages of using autogenous bone grafts. This article primarily focuses on the use of autogenous onlay bone grafts to reconstruct the atrophic maxilla.

A modified socket seal surgery with composite graft approach.

The contour of the residual ridge is reduced within 1 year by approximately 25% in width after the extraction of a natural tooth. The augmentation of a tooth socket after an extraction decreases the loss of available bone width for an endosteal implant. Grafting at the same time as the extraction has benefits from both a patient and doctor perspective. However, primary closure is more difficult, and may require the facial keratinized gingiva to be undermined and approximated on the crest of the ridge, or the use of membranes, which are exposed during the soft tissue healing. The modified socket seal surgery uses a technique described by Landsberg and couples his procedure with autologous bone harvested from the maxillary tuberosity. As a result, the tooth extraction socket may be augmented with autologous bone and connective tissue with a simplified approach at the same time as the extraction of a tooth.

Vertical bone augmentation using recombinant bone morphogenetic protein, mineralized bone allograft, and titanium mesh: a retrospective cone beam computed tomography study.

PURPOSE This retrospective study evaluated the use of a composite graft of recombinant human bone morphogenetic protein-2 (rhBMP-2) and particulate mineralized bone allograft protected by a titanium mesh for vertical bone augmentation. MATERIALS AND METHODS A review of data on patients from four oral and maxillofacial surgery practices in the United States who required vertical augmentation prior to implant treatment was conducted. Vertical augmentation was accomplished with rhBMP-2 in an absorbable collagen sponge (ACS) carrier and particulate allograft. Cone beam computed tomography was used to measure vertical bone gains using this technique. RESULTS Sixteen vertical ridge augmentation procedures were performed in 15 patients. The maximum vertical bone gains ranged from 4.4 to 16.3 mm. The average maximum vertical bone gain was 8.53 mm. The procedure allowed implant placement in all patients. Forty implants were inserted into the grafted ridges after a minimum of 6 months of healing. All implants integrated and were used for prosthetic support. CONCLUSION This study suggests that rhBMP-2/ACS and particulate mineralized bone allograft protected by a titanium mesh offers favorable vertical bone gains to allow dental implant placement.