Bücher und Digitale Medien

The present study aimed to evaluate the osseoconduction ability of an airborne particle-abraded and etched (SAE) titanium alloy surface when placed in humans with poor bone quality. Four patients scheduled to receive an implant-supported full-arch prosthesis received two additional reduced-diameter implants to be harvested after 6 months of submerged healing. Undecalcified vestibulopalatal/vestibulolingual histologic sections were prepared after the micro-computerized tomography (μCT) examination. Six implant sides from four biopsied implants displayed a type IV bone environment and were included in the present study. Bone-to-implant contact (BIC) was first measured on each implant side. The estimated initial BIC (E-iBIC) was evaluated by superimposing the implant profile 0.25 mm away from its actual position. The μCT provided information about the local and adjacent bony architecture. The mean BIC was 62.5% ± 10.6%, while the mean E-iBIC was 33.1% ± 4.4%. The E-iBIC/BIC ratio was 1.81 ± 0.38. The 3D μCT sections showed the thin bone trabeculae covering the implant surface; although they seemed to be separated from the rest of the bony scaffold, they were much more interconnected than what appeared to be on the 2D histologic preparations. This limited number of human histologic samples document, for the first time, that the SAE titanium alloy implant surface is apparently osseoconductive when placed in poor human bone quality. The average BIC was 1.81 times higher than the E-iBIC. This high osseoconductivity may explain the predictable clinical behavior of implants with this type of SAE textured surface in type IV bone.

Objectives: The aim of this retrospective study was to evaluate the effect of vertical soft tissue thickness (STT) on crestal bone loss (CBL) of early loaded implants after 1 and 5 years. Method and materials: Forty-four tapered implants with platform switching and conical connection were placed in the posterior mandible and maxilla to rehabilitate edentulous sites. STT at implant sites was divided into two groups: thin (n = 21, mean STT = 2.0 ± 0.3 mm) and thick (n = 23, mean STT = 3.0 ± 0.8 mm). The implants were loaded after 6 to 8 weeks. Survival and success rates and CBL were measured after 1 and 5 years. Results: The survival and success rates at 1 and 5 years were 100% and 97.8%, respectively. At the 1-year follow-up, the CBL of the thin and thick gingival groups was 0.96 ± 0.49 and 0.55 ± 0.41 mm, respectively; the difference was statistically significant (P = .004). At 5 years, the CBL of the thin and thick gingiva groups increased to 1.12 ± 0.84 and 0.65 ± 0.69 mm, respectively; the difference was not statistically significant (P = .052). Conclusion: At 1 year, the CBL was more pronounced at sites with a thin gingiva; at 5 years the difference between the groups was not statisically significantly different. Within the limitations of this study, early loading of implants with platform switched and conical connection was safe. Schlagwörter: crestal bone loss, dental implants, early loading, platform switching, soft tissue thickness

Objective: To report and evaluate ultrasonic bone surgery (USBS), also known as piezosurgery, in split-crest procedures with immediate implant placement at 3 years of follow-up. Method and Materials: Sixty-one split-crest procedures were performed, and 180 implants were placed in 43 patients. Initial ridge width varied between 1.5 and 5.0 mm (mean 3.3 ± 0.7 mm). Bone density was type I (11.1%), type II (27.8%), type III (28.9%), and type IV (32.2%). The USBS device worked with a 20 to 32 kHz vibrating frequency and 90 W peak power. Results: Mean split length was 14.8 ± 10.8 mm; mean final ridge width was 6.0 ± 0.4 mm. At second-stage surgery, five of 180 implants failed to osseointegrate (2.8%), all in the maxilla. Also at second-stage surgery, the success rate of the implants placed simultaneously to the split crest performed with USBS was 97.2% overall, 95.1% in the maxilla and 100% in the mandible. No loaded implant failed during the 3-year followup; respective success rates were unchanged. Conclusions: USBS is predictable to perform split-crest procedures, without risk of bone thermonecrosis; it decreases the risk of soft tissue alteration. Bone-cutting efficiency was satisfactory with the present USBS device because of its elevated ultrasonic vibrating power, especially in soft type IV bone. Schlagwörter: Bio-Oss, bone density, dental implants, piezosurgery, PRP, split-crest, ultrasonic bone surgery

This paper presents ultrasonic surgery (ie, Piezosurgery) as a new, relevant, and predictable method for performing atraumatic tooth extraction and subsequent implant site preparation. Forty noninfected teeth or roots were extracted in 23 patients and replaced immediately with implants. Extraction consisted of cutting the fibers of the periodontal ligament with vibrating tips of up to 10 mm in depth; the teeth or roots were mobilized afterward with an elevator. All teeth/roots were removed without fracture. Implant osteotomies were performed using conical tips of increasing diameters. During implant placement, notching of the apical third of the palatal wall or the interradicular bridge was performed without complication due to uncontrolled movements of the instrument. After a mean healing period of 2.4 months, all implants were osseointegrated and have been successfully loaded for at least 12 months. By implementing Piezosurgery, extraction can be atraumatic and implant placement can be predictable and undemanding compared to the use of burs, which can lead to instruments slipping during the procedure.

Purpose: Achieving implant primary stability in poor-density bone is difficult when the available bone height is less than 6 mm. This study assesses the 1-year clinical performance of tapered implants in sites of reduced height in combination with osteotome sinus floor elevation without bone grafting material. Materials and Methods: An osteotome sinus floor elevation procedure without grafting material was performed in the atrophic posterior maxilla. Tapered implants were placed in maxillary sites with residual bone height of 1 to 6 mm. Implant primary stability was assessed by finger pressure exerted on the implant. Bone gain in the elevated sinus and crestal bone loss were evaluated at 1 year via radiographs. Results: Fifty-four tapered implants were placed in 32 patients and were loaded after a mean of 4.2 ± 1.6 months. The mean maxillary residual bone height was 3.8 ± 1.2 mm. All implants achieved primary stability, and all were successfully loaded. At the 1-year radiographic control, the mean bone gain within the sinus was 2.5 ± 1.7 mm and the mean crestal bone loss was 0.2 ± 0.8 mm. Conclusions: In the atrophic posterior maxilla, primary stability can readily be achieved with tapered implants, even when the mean residual bone height is 3.8 mm. Despite limited bone support and lack of grafting material, all loaded implants were clinically stable, and crestal bone loss was limited. A net bone gain of 2.3 ± 1.8 mm was observed. Survival and success rates were 100% and 94.4%, respectively. Elevation of the sinus membrane without the addition of bone grafting material led to bone formation beyond the original limit of the sinus floor. Schlagwörter: atrophic posterior maxilla, crestal bone loss, dental implants, grafting material, osteotome, sinus lift, tapered implants

Ultrasonic bone surgery was recently introduced as an osteotomic technique; however, documentation is scarce. This article reports on the application of ultrasonic bone surgery for 53 bone-augmentation procedures in the posterior maxilla in 34 patients over 5 years. The initial residual bone height under the sinus varied between 1 and 9 mm (mean: 3.7 mm). Distribution according to residual bone height classes was 7.7% for Class B, 39.3% for Class C, and 53.0% for Class D. The procedures included bony window opening of the sinus, cortical and cancellous bone harvesting, and activation of the sinus wall. During the sinus approach, 2 of 53 membranes (3.8%) were perforated and covered with a membrane made of platelet-poor plasma. Bone grafting was carried out with autologous bone at 22 implant sites (18.8%), with a mixture of autologous bone and anorganic bovine bone mineral (Bio- Oss) at 29 sites (24.8%), and with Bio-Oss alone at 66 sites (56.4%). The perforated membranes healed uneventfully. At second-stage surgery, four implants failed. The survival rate of the 117 placed implants was 96.6%. No implant failed after loading. Performing the sinus grafting procedure with ultrasonic bone surgery limited the occurrence of membrane perforation; by changing the tips, all surgical steps were performed safely and comfortably.

The application of immediate loading of implants in the edentulous maxilla in multiple-risk patients is presented. Five partially edentulous patients attended with failing prostheses supported by hopeless teeth. An immediate-loading protocol was proposed because the patients rejected provisionalization with a removable prosthesis. Multiple teeth were extracted, and 44 immediately loaded implants were placed, most of them (55.5% to 88.9%) in fresh extraction sites, to support a cross-arch prosthesis that was loaded 3 to 4 days after surgery. The overall implant failure rate was 13.4%; in healed sites it was 20% (2/10) and in fresh extraction sites it was 8.82% (3/34). Prosthetic success was 100%. The overall failure rate was higher than is usually seen with the standard delayed-loading approach. Nevertheless, this immediate-loading protocol was satisfactory for the patients and the practitioner because prosthetic success was maintained during the provisionalization phase.

Purpose: Evaluation of prosthetic complication was performed on 236 patients treated with 528 implants in an 8-year private practice experience. Materials and Methods: The study sample included 55 overdentures (ODs) and 265 fixed partial dentures (FPDs). Among the latter, 231 FPDs were cemented and 34 were screw-retained. The type and frequency of prosthetic incidents were recorded, including adjustments and complications. Statistical analysis was performed using a chi-square test to identify risk factors associated with complications. Results and Discussion: Over this period, 1 abutment fractured and 2 became loose, leading to a cumulative implant component success rate of 99.2%. Patients with removable prostheses had more complications than those with fixed ones, 66.0% versus 11.5%; the difference was significant (P < .001). Posterior fixed prostheses had more complications than anterior ones, 11.0% versus 0%; however, the difference was not significant (P = .16). The complication rates for cemented and screw-retained prostheses did not differ significantly (10.4% versus 5.9%; P = .61). Prostheses with an extension cantilever had more complications, 29.4% versus 7.9%; the difference was significant (P = .01). In the OD group, the ball-retained prostheses had a significantly higher rate of complications than the bar-retained ones (77.5% versus 42.9%; P = .04). In the FPD group, complications were not recurrent; most occurred during the first 2 years, and the rate of complications did not increase with time. In the OD group, 1.3 incidents per prosthesis were recorded. Incidents were often recurrent, and the rate of complications did not decrease with time. Conclusions: Removable and fixed prostheses were associated with complications at different frequencies and of different types. In the removable group, adjustments and foreseeable complications were numerous, recurrent, and usually easy to manage. Bar-retained prostheses had fewer complications than ball-retained ones. In the fixed group, complications were limited in number and did not increase with time. Complications were restricted to the posterior region. (Case Series)

Purpose: This article provides preliminary clinical results on the Osseotite NT implant, which was developed to simplify surgical procedure and cover an extended range of indications. Placement characteristics of NT and standard Osseotite implants were also compared in an in vitro study. Materials and Methods: The in vitro placement characteristics of NT and standard Osseotite implants of 4.0 mm diameter and 8.5 to 15 mm in length were compared. In addition, a total of 182 NT implants (96 maxillary and 86 mandibular) were placed in 92 patients; of these, 87.9% were placed using a 1-stage technique. The implants were placed in healed sites (43.9%), fresh extraction sockets (37.4%), or recent extraction sites (2 months postextraction) (18.7%). Before restoration, healing times of 3 to 4 months in the mandible and 5 to 6 months in the maxilla were allowed. The entered implant length in the osteotomy site before contacting the bony walls (EILOS) was compared, as well as the number of turns and the time required to seat the implants. Cumulative survival rates (CSRs) were calculated for up to 18 months of follow-up after surgery. Results: The EILOS was between 47.3% and 57.6% of implant length for the NT implants; for the standard implants, it was between 12.0% and 21.2%. With the NT implants, the number of turns and the placement time were reduced by 61% to 64% and 61% to 65%, respectively. In the clinical study, 4 implants failed during the healing period; none failed after prosthesis placement. The CSR was 97.79% for implants placed into fresh or recent extraction sites; in healed sites, the CSR was 98.75%. The cumulative prosthetic success rate was 100%. Discussion: This new implant design is seated with special drills; the drilling sequence requires less time and less torque than that used for standard implants. The low failure rate after prosthetic loading was consistent with that observed for standard Osseotite implants. Conclusion: These preliminary data suggest that the NT implant can be predictable in healed sites and fresh or relatively recent extraction sockets.

Purpose: This article reports the preliminary data from a clinical study of immediately loaded, full-arch, screw-retained prosthesis with distal extensions (hybrid prosthesis) supported by Osseotite implants placed in the edentulous mandible. Materials and Methods: Fifteen patients who received 103 implants were enrolled in this study. The first 2 patients received both immediately loaded and submerged implants, while the remaining patients had all implants immediately loaded. The first 9 patients received a temporary prosthesis within 4 hours of surgery, and the hybrid prosthesis, made of a titanium framework and acrylic resin teeth, was placed after 6 months. The last 6 patients received the same type of hybrid prosthesis within 36 hours of surgery. Marginal bone loss was monitored via periapical radiographs by a computerized technique. Results: One failure (out of the 92 immediately loaded implants) occurred after 3 weeks of function because of infection. A cumulative success rate of 98.9% was achieved for up to 48 months of follow-up, while the prosthetic cumulative success rate for the same period was 100%. Marginal bone loss at the immediately loaded implants was within the generally accepted conventional limits for standard delayed loading protocols. Discussion: This technique can reduce treatment time but should be applied with caution. Conclusion: The preliminary results of this study suggest that rehabilitation of the edentulous mandible by an immediately loaded hybrid prosthesis supported by 5 to 6 implants may represent a viable alternative treatment to the classical delayed loading protocols.