Ole T. Jensen

Marginal Bone Stability Using 3 Different Flap Approaches for Alveolar Split Expansion for Dental Implants—A 1-Year Clinical Study

PURPOSE Width augmentation for the alveolar process using alveolar split procedures has not been studied in a comparative study with regard to marginal bone stability. Most research in this regard has used implant osseointegration as an endpoint for the success of the bone grafting procedure. The purpose of the present clinical trial was to retrospectively evaluate the stability of the buccal crestal bone around dental implants placed into alveolar split graft sites using 3 different approaches: a minimal flap, a partial-thickness flap, and a full mucoperiosteal flap. Implants were placed simultaneously or delayed to alveolar split grafting. The aim of the present study was to do a comparative analysis of these 3 techniques by clinical detection for the presence or absence of marginal bone using a periodontal probe 1 year after implant restoration. The working hypothesis was that detachment or disturbance of the blood supply of the buccal plate would be influenced by the flap procedure used and would therefore affect the late marginal bone stability around the implants. MATERIALS AND METHODS A total of 40 consecutive patients were treated in 2 different practice locations (20 at each office) with alveolar split procedures and simultaneous implant placement, using 3 different flap approaches and were seen again after 1 year at the 2 private office locations. The patients were in general good health, without active periodontal disease. All patients were nonsmokers. Patients with diabetes mellitus were excluded from the study. The aim of the present study was to establish the stability of the mobilized buccal bone plate, which could only be observed indirectly. The method used to detect the presence or absence of buccal marginal bone was a blunt periodontal probe used in the sulcus on the facial surface of the restored implant or a sharp explorer used transgingivally to detect marginal bone presence. However, the bone thickness could not be established using either of these methods. This was done in both practice locations by the surgeon who had performed the procedure (in a few cases, open flap procedures were done up to 1 year after grafting, which permitted direct observation of the original treatment site). The 3 different flap approaches studied were full-thickness flap reflection, partial-thickness flap reflection, and minimal flap reflection of the osteoperiosteal flap approach to crestally split and then widen the alveolus. RESULTS A total of 40 consecutive patients treated with 65 alveolar split expansion procedures done in 2 practice locations during a 2-year period were statistically analyzed retrospectively for buccal bone augmentation presence and implant restorability after 1 year of healing. Facial bone loss of 2 mm or more was seen in 11 sites, 10 of which were full flap reflections and 1 an osteoperiosteal flap site. Implant osseointegration was 92.5% for the osteoperiosteal flaps, 93.3% for the partial-thickness flaps, and 94.4% for the full-thickness flaps. CONCLUSIONS The 3 flap approaches to alveolar widening by crest splitting with implant placement had a sustained increased alveolar width after 1 year. However, most full flap alveolar split cases had facial bone loss and gingival recession. The osteoperiosteal flaps (book flap) and partial-thickness flaps showed stable buccal bone patterns. The results of the present clinical study of relatively early osseous remodeling suggest that full mucoperiosteal flaps should not be reflected when an alveolar split is done. However, to further elucidate the marginal bone vitality, a longer study period must be undertaken to more fully validate the alveolar split procedure and verify the best flap approach.

The All-on-4 Shelf: Maxilla

All-on-4 treatment is facilitated by bone reduction to create prosthetic restorative space, establish maximum anterior posterior spread of implants, and to avoid pneumatized sites. Unlike a reduction alveloplasty for denture placement, the All-on-4 shelf enables optimal surgical prosthetic management of implant placement for the fixed hybrid prosthesis.

Maxillary All-On-Four Therapy Using Angled Implants: A 16-Month Clinical Study of 1110 Implants in 276 Jaws

The maxilla is a challenging area for dental implant restoration. Encroachment of anatomic structures such as the sinus and nasal floor make vertical placement difficult. Implants placed at an angle may be used to avoid these anatomic structures or eliminate the need for a bone grafting procedure. The question occasionally arises about the possible detrimental effects of placing implants at an angle. This article reviews relevant literature, presents two case reports on maxillary angled implants and presents 3 years of data on 276 All-on-Four restorations.

The Book Flap: A Technical Note

PURPOSE To present a useful technique for widening the thin alveolar ridge for placement of an implant or bone graft. MATERIALS AND METHODS A partial soft tissue flap is elevated over the alveolar ridge and the ridge is split with an osteotome. The technique out-fractures the buccal plate and maintains the labial soft tissue to preserve the blood supply to the buccal bone. RESULTS The book flap has been employed in over 500 cases over the past 12 years. Approximately 90% were successful in providing adequate width to accommodate an implant. Infection occurred in approximately 2% of cases. The average gain in width was around 3 mm. CONCLUSION This technique can be employed often and has a very low complication rate.

Trans-sinus dental implants, bone morphogenetic protein 2, and immediate function for all-on-4 treatment of severe maxillary atrophy.

PURPOSE The aim of this study was to evaluate the clinical outcomes of trans-sinus dental implant placement by use of bone morphogenetic protein 2 (BMP-2) grafting and immediate functional loading by the all-on-4 scheme. PATIENTS AND METHODS After bone reduction to create the all-on-4 shelf or because of severe maxillary atrophy and prominent sinus anatomy, 10 patients were selected to undergo trans-sinus implant placement and simultaneous BMP-2 sinus floor grafting for immediate provisional loading. Insertion torque was measured upon implant placement. Patients were followed up for at least 1 year after final restoration when either a computed tomography scan or panoramic radiograph was obtained and analyzed for the presence of trans-sinus peri-implant bone. Hounsfield units were recorded mid sinus graft. RESULTS Of 19 trans-sinus implants, 18 remained integrated at the 1-year follow-up, for a 5.2% failure rate. All sinus grafts formed bone, with a mean of 460 Hounsfield units. Final fixed prostheses were completed for all 10 patients. CONCLUSION Trans-sinus dental implant placement with BMP-2 grafting to gain anterior-posterior spread for immediate function by use of all-on-4 treatment appears to be a viable alternative to the use of zygomatic implants in the presence of severe maxillary atrophy.

Minimum criteria for immediate provisionalization of single-tooth dental implants in extraction sites: a 1-year retrospective study of 100 consecutive cases.

PURPOSE Minimum criteria were used in the placement of 100 consecutive provisional restorations on single-tooth dental implants placed into extraction sites within 3 days of surgery. MATERIALS AND METHODS Provisional restorations were placed on 4.1- and 4.8-mm diameter standard ITI (Straumann, Waltham, MA) implants in the anterior mandible and maxilla in 100 treatment sites over a 3-year period. Provisionals were placed despite low insertion torque values of 15 N-cm or 50 implant stability quotient using radiofrequency analysis. Implants had final impressions for definitive restorations done 8 to 12 weeks after implant placement. All patients were recalled 1 year after restoration and evaluated according to parameters suggested by Albrektsson et al (Int J Oral Maxillofac Implants 1:11, 1986). RESULTS One implant was not osseointegrated. The remaining implants were judged successful at the 1-year recall appointment. CONCLUSION Immediate provisionalization of implants placed into fresh extraction sites can be effective even when minimal provisionalization criteria are met.

Alveolar sandwich osteotomy in resorbed alveolar ridge for dental implants: a 4-year prospective study.

PURPOSE To answer whether severe vertical alveolar defects can be resolved using the sandwich osteotomy technique with xenograft material as filler and to evaluate the predictability of this procedure. MATERIALS AND METHODS Ten graft sites (5 mandibular and 5 maxillary) in 9 patients treated at the Department of Oral and Maxillofacial Surgery, Hadassah Medical Center, were included in the present study. The patients underwent vertical bone augmentation using the sandwich osteotomy technique filled with xenograft material. The degree of bone augmentation was analyzed clinically at surgery and 4 to 6 months later from the computed tomography images taken just before the sites had been rehabilitated using dental implant insertion. A trephine histologic analysis was performed during implantation at 1 maxillary site. RESULTS The mean vertical bone gain in the interval between the sandwich osteotomy and implementation was 6 mm (range 4 to 10), and it remained stable after 4 to 6 months. In 2 cases, additional horizontal bone augmentation was needed. All graft sites were rehabilitated using dental implants with satisfactory results. In 3 cases, gingival porcelain was required for the final prosthesis. Histologic examination revealed vital segmentized bone and remodeling of the filled gap. CONCLUSIONS The interpositional alveolar bone graft using xenograft filler appears to be a viable and predictable alternative to block grafting or guided bone regeneration, resulting in good final results, with substantial vertical bone gain, even for challenging cases.

Island Osteoperiosteal Flap for Alveolar Bone Reconstruction

The island osteoperiosteal flap (I-flap) is introduced as a modified alveolar split bone grafting technique used to gain width and modify the facial or buccal bone plate position. Three case examples are shown as well as animal histology indicating the possible development of this new surgical procedure as an adjunct for alveolar augmentation and implant therapy.

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.

Mandibular All-On-Four Therapy Using Angled Implants: A Three-Year Clinical Study of 857 Implants in 219 Jaws

Immediate function with Brånemark implants is well established for the mandible. This article describes a series of 857 implants placed consecutively in which very few implants failed or lost bone despite the dynamic healing conditions of simultaneous dental extractions and bone leveling. Though these findings are relatively early, 3 years or fewer, it appears that the immediate function All-on-Four procedure can be done with a high degree of confidence for the mandible--putting into question the need for additional implants.