Marco Degidi

Maxillary Sinus Augmentation With Different Biomaterials: A Comparative Histologic and Histomorphometric Study in Man

Objective:Rehabilitation of the edentulous posterior maxilla with dental implants can be difficult because of insufficient bone volume caused by pneumatization of the maxillary sinus and crestal bone resorption. Different biomaterials have been used for sinus augmentation. The aim of the study was to compare different materials in maxillary sinus augmentation in man. Methods:A total of 94 patients participated in this study. Inclusion criteria were maxillary partial (unilateral or bilateral) edentulism involving the premolar/molar areas, and the presence of 3–5-mm crestal bone between the sinus floor and alveolar ridge. A total of 362 implants were inserted. There were 9 biomaterials used in the sinus augmentation procedures. Each patient underwent 1 biopsy after 6 months. A total of 144 specimens were retrieved. Results:None of the 94 patients had complications. All implants were stable, and x-ray examination showed dense bone around the implants. Mean follow-up was 4 years. There were 7 implants that failed. Histologic resultsshowed that almost all the particles of the different biomaterials (i.e., autologous bone, demineralized freeze-dried bone allograft Biocoral® [Inoteb, St. Gonnery, France], Bioglass® [US Biomaterials, Alachua, FL], Fisiograft® [Ghimas, Bologna, Italy], PepGen P-15TM [Dentsply Friadent CeraMed, Lakewood, CO], calcium sulfate, Bio-Oss® [Geistlich Pharma AG, Wohlhusen, Switzerland], and hydroxyapatite) were surrounded by bone. Some biomaterials were more resorbable than others. Included are the histomorphometry clarified features of the newly formed bone around the different grafted particles. Conclusion:All biomaterials examined resulted in being biocompatible and seemed to improve new bone formation in maxillary sinus lift. No signs of inflammation were present. The data are very encouraging because of the high number of successfully treated patients and the good quality of bone found in the retrieved specimens.

A 7-year Follow-up of 93 Immediately Loaded Titanium Dental Implants

Recently, several experimental and clinical investigations found that immediately loaded implants obtained satisfactory levels of osseointegration with high success percentages. Only a few long-term studies of immediately loaded implants have been reported in the literature. The aim of this study was a 7-year clinical and radiographic follow-up of 93 immediately loaded dental implants in human patients. Eleven patients were consecutively enrolled in this study. A total of 7 full and 9 partial edentulous arches were rehabilitated. Patients presented a completely edentulous mandible (n=6), a completely edentulous maxilla (n=1), mandibular posterior edentulous areas (n=5), or a posterior maxillary edentulous area (n=1). Patients were rehabilitated with a bar and an overdenture (n=4), a provisional prosthesis of 3 to 12 elements (n=11), or a metal-ceramic bridge of 10 elements (n=1). A total of 93 implants were inserted and loaded within a 24-hour time frame. Six implants failed in the first year after loading. No more failures were observed in the following 6 years, and all the other implants were well integrated from a clinical and radiographic point of view. The cumulative success rate at 7 years was 93.5%, and the prostheses survival rate was 98.5%. The mean marginal bone loss was 0.6 mm after the first year and 1.1 mm at the 7-year evaluation. Primary stability is one of the most important parameters in immediately loaded implants because it avoids micromotion at the bone-implant interface. Four of the 6 failures in our patients occurred in partially edentulous patients; an excessive load applied to these small bridges could be the reason for the failure. Also, the bone quality is important, for 3 of our failed implants had been inserted in D3 bone. Our clinical and radiographic results have shown that these immediately loaded implants have remained osseointegrated for a long period. Our results point to the possibility of using the immediate loading technique in selected and well-informed cases.

10‐Year Follow‐Up of Immediately Loaded Implants with TiUnite Porous Anodized Surface

BACKGROUND The immediate loading of implants with a porous anodized surface is a well-described technique. Few data are however available on the long-term outcomes. PURPOSE The aim of this prospective study was to assess the 10-year performance of TiUnite implants supporting fixed prostheses placed with an immediate loading approach in both postextractive and healed sites. MATERIALS AND METHODS All patients received a fixed provisional restoration supported by immediately loaded parallel design, self-tapping implants with a porous anodized TiUnite surface, and an external-hexagonal connection. Both healed and postextractive cases were included. Success and survival rate for restorations and implants, changes in marginal peri-implant bone level, probing depth measurements, biological or technical complications, and any other adverse event were recorded at yearly follow-up up to 10 years after surgery. RESULTS A total of 210 implants fulfilled the inclusion criteria and were consecutively placed in 59 patients. Forty-seven (22.38%) implants were lost because of the recalled patient refused to attend the planned 10-year follow-up. Five over 210 (2.38%) implants were lost. At the final follow-up, the accumulated mean marginal bone loss and probing depth were, respectively, 1.93 mm (SD 0.40) and 2.54 mm (SD 0.44) for the implants placed in healed sites (n = 84); 1.98 mm (SD 0.37) and 2.63 mm (SD 0.39) for the implants placed in postextractive sites (n = 74). The restorations examined achieved a cumulative 65.26% success rate and 97.96% survival rate. The implants placed in healed and postextractive sites, respectively, achieved a 98.05% and a 96.52% cumulative survival rate. CONCLUSIONS Positive results in terms of bone maintenance in the long-term perspective are to be expected using immediately loaded implants with a TiUnite porous anodized surface in both postextractive and healed sites when adequate levels of oral hygiene are kept.

Residual aluminum oxide on the surface of titanium implants has no effect on osseointegration

The cleanliness of titanium dental implants surfaces is considered to be an important requirement for achieving osseointegration, and it has been hypothesized that the presence of inorganic contaminants could lead to lack of clinical success. Aluminum ions are suspected to impair bone formation by a possible competitive action to calcium. The objective of the present study was to describe the effects of residual aluminum oxide particles on the implant surface on the integration of titanium dental implants as compared to decontaminated implants in a rabbit experimental model. Threaded screw-shaped machined grade 3 c.p. titanium dental implants, produced with high-precision equipment, were used in this study. The implants were sandblasted with 100-120 microm Al2O3 particles at a 5atm pressure for 1min, then 24 implants (control implants) underwent ASTM F 86-68 decontamination process in an ultrasonic bath. The other 24 implants (test implants) were washed in saline solution for 15min. Both test and control implants were air-dried and sterilized at 120 degrees C for 30min. After sterilization the implants were inserted into the tibiae (two test and two control implants in each rabbit). Twelve New Zealand white mature male rabbits were used in this study. The protocol of the study was approved by the Ethical Committee of our University. No complications or deaths occurred in the postoperative period. All animals were euthanized, with an overdose of intravenous pentobarbital, after 4 weeks. A total of 48 implants were retrieved. The images were analyzed for quantitation of percentage of surface covered by inorganic particles, bone-implant contact, multinucleated cells or osteoclasts in contact with the implant surface and multinucleated cells or osteoclasts found 3mm from the implant surface. The differences in the percentages between the two groups have been evaluated with the analysis of variance. The implant surface covered by inorganic particles on test implants was significantly higher than that of control implants (p=0.0000). No statistically significant differences were found in the bone-implant contact percentages of test and control implants (p=0.377). No statistically significant differences were found in the number of multinucleated cells and osteoclasts in contact with the implant surface (p=0.304), and at a distance of 3mm from the implant surface (p=0.362). In conclusion, our histological results do not provide evidence to support the hypothesis that residual aluminum oxide particles on the implant surface could affect the osseointegration of titanium dental implants.

Immediate Versus One-Stage Restoration of Small-Diameter Implants for a Single Missing Maxillary Lateral Incisor: A 3-Year Randomized Clinical Trial

BACKGROUND The aim of this study was to compare the bone loss pattern and soft tissue healing of immediately versus one-stage loaded 3.0-mm-diameter implants in cases involving a single missing lateral maxillary incisor. METHODS Sixty patients with a missing lateral incisor in the maxilla were randomized to one of the treatments: 30 patients in the immediate-restoration group and 30 patients in the one-stage group. All implants were placed in healed sites and had to be inserted with a torque >25 Ncm. The implants in the immediate-restoration group were fitted with a non-occluding temporary crown on the day of surgery. Both groups received a full occluding final crown 6 months after surgery. Mean marginal bone loss, probing depth, and bleeding on probing were assessed at 6-, 12-, 24-, and 36-month follow-up examinations by a masked examiner. RESULTS Sixty 3.0-mm-diameter implants were placed between July 2003 and February 2006; 27 (45.0%) were in men, and 33 (55.0%) were in women. All implants osseointegrated and were clinically stable at the 6-month follow-up. No statistically significant differences were observed for bleeding or plaque index. No implant fractures occurred. At the 36-month follow-up, the accumulated mean marginal bone loss and probing depth were 0.85 +/- 0.71 mm and 1.91 +/- 0.59 mm, respectively, for the immediate-loading group (n = 30) and 0.75 +/- 0.63 mm and 2.27 +/- 0.81 mm, respectively, for the one-stage group (n = 30). There was no statistically significant difference (P >0.05) for the tested outcome measures between the two procedures. CONCLUSIONS In the rehabilitation of a single missing lateral maxillary incisor, no statistically significant difference was assessed between immediately and one-stage restored small-diameter implants with regard to implant survival, mean marginal bone loss, and probing depth. Three-millimeter-diameter implants proved to be a predictable treatment option in our test and control groups if a strict clinical protocol was followed.

Immediate loaded dental implants: comparison between fixtures inserted in postextractive and healed bone sites.

In the last two decades, several investigators have reported immediate placement of dental implants into extraction sockets achieving excellent results with a two-stage surgical procedure. Recently, immediate loading (IL) has become an emerging technique because it has been documented to be a successful and time-saving procedure. Regarding the possibility of immediate/early loading of implants placed in fresh extraction sockets, few reports are available. In addition, they are based on limited series with short follow up. Thus, we decided to perform a retrospective study on a large series of postextractive IL implants. From January 1995 to October 2004, 416 IL fixtures were placed immediately after extraction and 658 IL fixtures in healed sites. The mean follow up is 3 years. Multiple implant systems were used. Because only eight of 1074 implants were lost (i.e., survival rate, 99.3%) and no statistical differences were detected among the studied variables, no or reduced marginal bone loss was considered as an indicator of success rate to evaluate the effect of several host-, surgery-, and implant-related factors. A general linear model was then performed to detect those variables statistically associated with marginal bone loss. Only eight of 1074 implants were lost (i.e., survival rate, 99.3%) and no differences were detected among the studied variables. On the contrary, the general linear model showed that younger age (cutoff, 55 years) and harder bone are related to a lower delta insertion abutment junction (or marginal bone loss) and thus a better outcome. We demonstrated that postextractive IL implants have a high survival rate and success rate that are similar to those reported in previous studies of two-stage procedures or in IL implants inserted in healed bone. Poor bone quality and older age correlate with a slight higher bone resorption.

Bone Remodeling in Immediately Loaded and Unloaded Titanium Dental Implants: A Histologic and Histomorphometric Study in Humans

Remodeling is thought to prevent microdamage accumulation caused by repetitive loading and to increase the fatigue life of bone. The bone remodeling rate (BRR) is the period of time needed for new bone to replace the existing bone and to allow for the adaptation of bone to its environment. BRR is expressed as a percentage or volume of new bone within a specific time period. The aim of the present study was to evaluate bone remodeling events on submerged and immediately loaded dental implants. Twelve patients with edentulous mandibles participated in this study. All patients were rehabilitated with fixed mandibular prostheses, with 10 dental implants per patient. An additional implant was inserted in the most distal posterior mandibular jaw region. In 6 patients, these additional implants were loaded with a fixed provisional prosthesis the same day of the implant surgery and loaded. In the other 6 patients, the additional implants were left submerged and not loaded. After 6 months, all the additional implants were retrieved with a trephine. The percentage of woven and lamellar bone, number of osteoclasts and osteoblasts, and percentage of bone labeled by tetracycline at 0.5 mm and 2 mm from the implant surface were evaluated. The percentage of lamellar bone, number of osteoblasts, and percentage of bone tetracycline labeling was significantly higher in the loaded implants than in the unloaded implants (P =.0001). Also in the loaded implants, the percentage of woven and lamellar bone, number of osteoclasts and osteoblasts, and percentage of bone tetracycline labeling was significantly higher at 0.5 mm than at 2 mm from the implant surface (P =.0001). No such differences were found in unloaded implants (P =.377). In conclusion, we found that (1) loading appeared to stimulate bone remodeling at the interface, (2) a higher percentage of lamellar bone was found in loaded implants, (3) the percentage of bone labeling was higher at the interface of loaded implants, (4) no differences were found in the BRRs between immediately loaded and unloaded implants, and (5) immediate loading had not interfered on the lamellar bone formation at the interface and had not produced formation of woven bone at the interface.

Cortical bone regeneration with a synthetic cell-binding peptide: a histologic and histomorphometric pilot study.

PepGen P-15 is a combination natural anorganic bovine-derived hydroxyapatite matrix (ABM) coupled with a synthetic cell-binding peptide (P-15). This material has been reported to enhance bone formation in periodontal osseous defects. The aim of this study was to assess the effect of ABM/P-15 on the healing of cortical bone defects in rabbits. Five New Zealand rabbits were used. Two 8-mm bone defects were created in each tibia. Eight defects were filled with PepGen P-15, 8 defects with PepGen P-15 Flow, and 4 defects were used as a control group. A total of 20 defects were created. All rabbits were killed at 4 weeks. Block sections containing the defects were retrieved and the specimens processed for light microscopy examination. Newly formed bone was present in both test groups, whereas, in the controlgroup, only a scarce quantity of newly formed bone was present and the cortical defects had not been filled by the regenerated bone. Statistical evaluation showed that there were statistically significant differences between control sites and sites treated with P-15 and P-15 Flow (P = 0.0001), and also between sites treated with P-15 and P-15 Flow (P = 0.0001), respectively. No acute inflammatory infiltrate cells were visible in both of these groups. Both PepGen P-15 and PepGen P-15 Flow enhanced new bone formation in the cortical drilled defects, whereas control defects showed very little newly formed bone.

Regeneration of the alveolar crest using titanium micromesh with autologous bone and a resorbable membrane.

Guided bone regeneration (GBR) has been used for the regeneration of bone in conjunction with the placement of oral implants. The aim of the present study was to clinically and histologically evaluate the use of a titanium micromesh and a resorbable membrane in the GBR technique in patients with alveolar crest defects due to periodontitis, trauma, and extractions. Eighteen patients participated in this study, and 50 implants were inserted. The postoperative healing was uneventful, no dehiscences were observed, and all implants were functioning successfully at 7-year follow-up. At reentry, in all cases, the space under the titanium mesh was completely filled by bone. From a clinical point of view, in all patients, no residual bone defects were observed and a significant increase of the alveolar width or height was found. In all cases, a good esthetic result of the restorative procedures was present.

Histologic Evaluation of 2 Human Immediately Loaded and 1 Submerged Titanium Implants Inserted in the Posterior Mandible and Retrieved After 6 Months

Abstract Immediate loading can be successfully used in implant dentistry. Many factors are thought to be of importance in obtaining mineralized tissues at the interface. One such factor is the impl...