Gerardo Pellegrino

Vertical ridge augmentation of the atrophic posterior mandible with interpositional bloc grafts: bone from the iliac crest vs bovine anorganic bone. Clinical and histological results up to one year after loading from a randomized-controlled clinical trial.

OBJECTIVES To compare two different techniques for vertical bone augmentation of the posterior mandible: bone blocs from the iliac crest vs. anorganic bovine bone blocs used as inlays. MATERIALS AND METHODS Ten partially edentulous patients having 5-7 mm of residual crestal height above the mandibular canal had their posterior mandibles randomly allocated to both interventions. After 4 months implants were inserted, and after 4 months, provisional prostheses were placed. Definitive prostheses were delivered after 4 months. Histomorphometry of samples trephined at implant placement, prosthesis and implant failures, any complication after loading and peri-implant marginal bone-level changes were assessed by masked assessors. All patients were followed up to 1 year after loading. RESULTS Four months after bone augmentation, there was statistically significant more residual graft (between 10% and 13%) in the Bio-Oss group. There were no statistically significant differences in failures and complications. Two implants could not be placed in one patient augmented with autogenous bone because the graft failed whereas one implant and its prosthesis of the Bio-Oss group failed after loading. After implant loading only one complication (peri-implantitis) occurred at one implant of the autogenous bone group. In 16 months (from implant placement to 1 year after loading), both groups lost statistically significant amounts of peri-implant marginal bone: 0.82 mm in the autogenous bone group and 0.59 mm in the Bio-Oss group; however, there were no statistically significant differences between the groups. CONCLUSIONS Both procedures achieved good results, but the use of bovine blocs was less invasive and may be preferable than harvesting bone from the iliac crest.

Vertical augmentation with interpositional blocks of anorganic bovine bone vs. 7-mm-long implants in posterior mandibles: 1-year results of a randomized clinical trial

OBJECTIVES To evaluate whether 7-mm-long implants could be an alternative to longer implants placed in vertically augmented posterior mandibles. MATERIALS AND METHODS Sixty patients with posterior mandibular edentulism with 7-8 mm bone height above the mandibular canal were randomized to either vertical augmentation with anorganic bovine bone blocks and delayed 5-month placement of ≥10 mm implants or to receive 7-mm-long implants. Four months after implant placement, provisional prostheses were delivered, replaced after 4 months, by definitive prostheses. The outcome measures were prosthesis and implant failures, any complications and peri-implant marginal bone levels. All patients were followed to 1 year after loading. RESULTS One patient dropped out from the short implant group. In two augmented mandibles, there was not sufficient bone to place 10-mm-long implants possibly because the blocks had broken apart during insertion. One prosthesis could not be placed when planned in the 7 mm group vs. three prostheses in the augmented group, because of early failure of one implant in each patient. Four complications (wound dehiscence) occurred during graft healing in the augmented group vs. none in the 7 mm group. No complications occurred after implant placement. These differences were not statistically significant. One year after loading, patients of both groups lost an average of 1 mm of peri-implant bone. There no statistically significant differences in bone loss between groups. CONCLUSIONS When residual bone height over the mandibular canal is between 7 and 8 mm, 7 mm short implants might be a preferable choice than vertical augmentation, reducing the chair time, expenses and morbidity. These 1-year preliminary results need to be confirmed by follow-up of at least 5 years.

Inlay versus Onlay Iliac Bone Grafting in Atrophic Posterior Mandible: A Prospective Controlled Clinical Trial for the Comparison of Two Techniques

PURPOSE To compare the efficacy of inlay and onlay bone grafting techniques in terms of vertical bone formation and implant outcomes for correcting atrophic posterior mandibles. MATERIALS AND METHODS Twenty surgical sites were assigned to two treatment groups, inlay and onlay, with iliac crest as donor site. After 3 to 4 months, 43 implants were placed and loaded 4 months later. The median follow up after loading was 18 months. RESULTS For the inlay versus onlay group, median bone gain was 4.9 versus 6.5 mm (p = .019), median bone resorption was 0.5 versus 2.75 mm (p < .001), and median final vertical augmentation was 4.1 versus 4 mm (p = .190). The implant survival rate was 100% in both groups, while the implant success rate was 90% versus 86.9% (p = .190, not significant). A minor and major complication rate of 20% and 10%, respectively, for both groups was encountered. CONCLUSIONS Inlay results in less bone resorption and more predictable outcomes, but requires an experienced surgeon. In contrast, onlay results in greater bone resorption and requires a bone block graft oversized in height, but involves a shorter learning curve. Once implant placement has been carried out, the outcomes are similar for both procedures.

Radiographic analysis of a transalveolar sinus-lift technique: a multipractice retrospective study with a mean follow-up of 5 years.

BACKGROUND Various sinus-lift techniques have been described in the literature. The aim of this retrospective study is to evaluate the efficacy of a transalveolar sinus-lift technique in terms of implant survival, marginal bone loss, and complications. METHODS A total of 538 patient records were examined, and after applying exclusion and inclusion criteria, a sample of patients was included with a mean follow-up of 5 years. Implants with a smooth or tapered surface were considered. Therefore, only sinus lifts with inorganic bovine bone matrix or demineralized bone matrix were included, and 1,536 periapical radiographs were analyzed. Outcome measures were implant success, implant failure (peri-implantitis and loss of osseointegration), marginal bone resorption, and biologic complications (membrane perforations, sinusitis, and intraoperative and/or postoperative hemorrhage). Periapical radiographs were evaluated before surgery, post-surgery, and after 6 months and 1, 3, and 5 years. We analyzed the residual crestal bone height under the sinus, the amount (mm) of height increase after surgery, and values of implant marginal bone resorption for considered follow-ups. RESULTS Two hundred eighty-two (282) patients were excluded. Therefore, 256 patients treated with the transalveolar sinus-lift technique were included. A total of 376 dental implants and 323 sinus lifts were analyzed. The overall rates of implant success and failure were 94.9% and 5.1%, respectively. The mean bone loss around implants was 1.98 mm (mean follow-up of 5 years). Patients treated with inorganic bovine bone matrix showed a better implant success rate (P = 0.03) than did patients treated with demineralized human matrix. Three Schneiderian membrane perforations occurred in the 323 sinus lifts. In these cases, the surgeon performed another surgical operation after 3 months. Postoperative complications were peri-implantitis (six cases) and osseointegration losses (13 cases). CONCLUSIONS The transalveolar sinus-lift technique was a safe, minimally invasive technique with an implant success rate comparable to traditional implantology. The implant success rate was positively affected by the low-resorption graft material, and a low bone-resorption rate around implants was found.

Computer-Aided Rehabilitation of Maxillary Oncological Defects Using Zygomatic Implants: A Defect-Based Classification

PURPOSE A complete maxillectomy for neoplastic lesions leads to serious oral dysfunction. Zygomatic implants for fixed bridge support are considered beneficial for maxillary defects after tumor resection. MATERIALS AND METHODS This clinical study examined the management of patients with different maxillary defect types who underwent delayed rehabilitation using zygomatic implants and immediate prosthetic loading. Virtual preoperative planning and intraoperative navigation were performed in all cases. RESULTS Five patients were treated with this new method. The total number of zygomatic implants positioned was 17. Four patients had immediate loading of a fixed prosthesis and 1 had delayed loading. One patient had 1 failed implant. CONCLUSION The use of preoperative virtual surgical planning and an intraoperative navigation system allows the surgeon to achieve safer implant positioning in a complex anatomic site. A systematic bone defect classification was created and a specific treatment protocol is proposed for each type of defect.

Vertical ridge augmentation of the atrophic posterior mandible with a 2-stage inlay technique: a case report.

The use of a 2-stage inlay technique in atrophic posterior mandibles with more than 10-mm thickness and less than 5-mm height above the inferior alveolar nerve is described. The first surgical procedure was a basic corticotomy of the buccal and lingual bone. One month later, a complete inlay procedure was performed. Computed tomography and conventional radiography showed a mean vertical bone gain of 11.5 mm. This 2-stage inlay technique avoids the use of chisels to complete bone osteotomy and reduces postsurgical nerve disturbances in atrophic posterior mandibles. This technique reduces intraprocedure and postoperative patient discomfort.

Titanium Mesh Technique in Rehabilitation of Totally Edentulous Atrophic Maxillae: A Retrospective Case Series.

BACKGROUND This study evaluates implant-borne prosthetic rehabilitation of 10 totally edentulous atrophic maxillae after bone reconstruction with a titanium-mesh technique and particulate bone graft. METHODS Ten atrophic maxillae were reconstructed with 19 titanium meshes and particulate autologous-heterologous bone. Maxillae were rehabilitated at least 5 months, with placement of 67 implants connected to the prostheses after an additional 4 months of rehabilitation. Cases were evaluated retrospectively in terms of complication rates, particularly on the amount of mesh exposure, implant survival, and success rates at the end of follow-up. RESULTS In seven cases, two meshes were prematurely exposed (within 4 to 6 weeks), and five were exposed later (after 4 to 6 weeks). Only two of the later exposures extended >1 cm(2). Nevertheless, reconstructions allowed implant placement and prosthetic rehabilitation in all cases. Two implants were lost before loading. After mean follow-up at 39.3 (20 to 56) months since prosthetic loading, all 65 implants were functional (100% implant survival), but 15 implants demonstrated a peri-implant mean bone resorption of 2.96 mm increased bone loss, yielding a cumulative implant success rate of 76.9%. No prosthetic problem was observed. CONCLUSIONS Use of titanium mesh with particulate bone can be considered a valid option in reconstructing atrophic maxillae to allow for implant-borne prosthetic rehabilitation. A high level of dehiscence did not compromise final outcome.

Simplifying Zygomatic Implant Site Preparation Using Ultrasonic Navigation: A Technical Note

Zygomatic implant site preparation could be considered a challenging procedure because of the use of a very long twist drill that could sometimes be difficult to control due to the need for drilling the malar bone on an oblique surface. Ultrasound was recently suggested to achieve better control, but the specific long tips required are not readily available, and the elongated tip also tends to reduce the efficacy. This technical note describes a proposal of a novel computer-aided technique to simplify the procedure of zygomatic implant site preparation. This method uses a standard-length ultrasonic tip to prepare the crestal bone and the zygomatic bone in two individual steps. The desired implant trajectory can be achieved during preparation using a real-time tracking navigation system. The combined use of the navigation system and the ultrasonic tips could aid the surgeon, during the first steps, in achieving optimal control of the instruments employed for the implant site preparation and keeping the planned zygomatic implant position. If the efficacy of the procedure is confirmed through clinical trials, this technique could also contribute to reducing the invasiveness of the procedure, promoting a smaller flap, and reducing the soft tissue damage.

Long-term results of osseointegrated implant-based dental rehabilitation in oncology patients reconstructed with a fibula free flap

BACKGROUND Dental rehabilitation with conventional prostheses after microvascular jaw reconstruction is often unsuccessful because of the altered oral anatomy and the lack of adequate dentition for fixation. PURPOSE This retrospective study evaluated the long-term outcomes of patients who underwent jaws reconstruction with a fibula free flap and subsequent rehabilitation with implant-supported prostheses. MATERIALS AND METHODS In total, 21 patients were enrolled; 108 osseointegrated dental implants, positioned on 21 fibular free flaps were assessed. Follow-up examinations were performed according to a standardized protocol, including clinical and radiological evaluations. The mean follow-up after implant insertion was 90.2 (range, 20-204) months. RESULTS The overall implant survival rate was 97.2% at the 12-month follow-up, 86.5% at 60 months, and 79.3% at 120 months. The rate of overall implant success was 95.4% at the 12-month follow-up, 73.5% at 60 months, and 64.7% at 120 months. Implant failure was more common in patients that had implants placed after they underwent radiation therapy. Peri-implantitis and mucositis were identified in 14.8% and 20.3% of surviving implants, respectively, at the 5- and 10-year follow-up. The risk of developing peri-implantitis was estimated to be higher (odds ratio = 1.5) for patients without connective tissue or skin grafts versus patients with one of them (18.2% vs 9.5%). CONCLUSIONS Long-term implant-related outcomes show that the survival rate of implants placed into the fibula is acceptable. Radiotherapy negatively impacts survival and success, in particular in the short and medium-term follow-up. Moreover, a relevant peri-implant bone resorption does occur over time and ultimately influences implants success, and it is mainly related to peri-implant gingival mucositis. In this regard skin or connective tissue grafts seem to offer an aid to manage this problem.

THREE-DIMENSIONAL IMPLANT POSITIONING WITH A PIEZOSURGERY IMPLANT SITE PREPARATION TECHNIQUE AND AN INTRAORAL SURGICAL NAVIGATION SYSTEM: CASE REPORT.

This case report describes new implant site preparation techniques joining the benefits of using an intraoral navigation system to optimize three-dimensional implant site positioning in combination with an ultrasonic osteotomy. A report of five patients is presented, and the implant positions as planned in the navigation software with the postoperative scan image were compared. The preliminary results are useful, although further clinical studies with larger populations are needed to confirm these findings.