Libri correalti

Aim: To report on a novel digital superimposition workflow that enables measuring the supra-crestal peri-implant soft tissue dimensions all along implant treatment and afterwards. Materials and Methods: A preoperative CBCT and intra-oral scans (IOS) are successively taken before surgery, at the end of the healing period, at prosthesis delivery, and over time; they are digitally superposed on a dedicated software. Then, the stereolithography files (STL) of the healing abutment, of the prosthetic abutment and the crown are successively merged into the superposition set of IOSs. Result: The workflow protocol of merging successively the STL of each item into the superposition set of IOSs enables capturing the dimensions of the height and width of the supra-crestal soft tissues, at every level of the healing abutment, the prosthetic abutment and the crown. In addition, it allows measuring the vertical distance that the crown exerts pressure on the gingiva and the thickness of the papillae at every level of the abutment. Conclusion: This novel digital superimposition workflow provides a straightforward method of measuring the vertical and horizontal dimensions of the supra-crestal peri-implant soft tissues, including the papillae, at each stage of the implant treatment process. It allows investigating a certain number of soft tissue variables that were previously inaccessible to clinical research. It should help enhancing our comprehension of the peri-implant soft tissue dynamics. Parole chiave: CBCT, clinical research, digital merging, gingival height, gingival width, intra-oral scan, papilla, peri-implant soft tissues

Aim: To compare the effect of the shape of the healing abutment, concave or straight, on the dimensions of the soft tissue after healing. Materials and methods: Patients needing implant therapy in the posterior area were treated with a 1-stage surgery protocol; concave (CONC) or straight (STR) healing abutments were randomly assigned after implant installation. Before surgery, a CBCT and an intra-oral scan were obtained (IOS#0); IOS#1 was taken after soft tissue healing. The CBCT, IOSs and STL of the abutments were merged; this allowed measuring the gained/lost gingival height (ΔH), the gingival width (GWAbut) and the emergence angles (ANG) of each group. Results: Twenty-seven implants (Ø 4.2 mm, SEVEN (MIS)) with 14 CONC and 13 STR healing abutments were available for analysis. ΔH of both groups did not differ statistically. The marginal gingiva of CONC either stayed within the abutment concavity (CONCin) or reached its straight portion beyond the concavity (CONCup). When GWAbut and ANG were measured without considering this feature, the differences between STR and CONC were not statistically significant. In contrast, once this feature was considered, the difference between the groups became statistically significant. For GWAbut, results were CONCup>STR>CONCin; for ANG it was STR≈CONCup>CONCin. Conclusion: Abutment shape did not affect the gingival height. Thickness of the gingiva at the concave abutment depended upon the position of the marginal gingiva, within or beyond the concavity. This exploratory pilot study might suggest that concave abutment height should be carefully chosen to ensure that the marginal gingiva reaches the level beyond the concavity. Parole chiave: CBCT, concave abutment, digital workflow, emergence angle, intra-oral scan, straight abutment, thickness of gingiva

Objective: Periodontal disease is caused by subgingival bacteria that adversely affect the host immune system and create and maintain unmitigated inflammation in gingival and periodontal tissues. The condition is also linked to systemic conditions including cardiovascular disease, diabetes, and arthritis. Periodontitis elevates the bacterial load and spreads systemic inflammation through infection and inflammation. The main radiographic sign of periodontitis is marginal bone loss. Risk factors, including medications, smoking, age, and sex, are known to influence periodontal health. However, there is little information about the impact of systemic conditions and medications on tooth wear. The aim of the present study was to assess the association between systemic conditions and medications and radiographic signs of tooth wear and marginal bone loss. Method and materials: This retrospective analysis was conducted on a group of 2,223 consecutive patients who came for dental treatment in the clinics of a large Health Maintenance Organization in Israel. Data available for the study included details of concomitant systemic diseases and medication and full-mouth radiographic surveys. Odds ratio and logistic regression analysis were used to detect associations between systemic conditions and medication, and marginal bone loss and tooth wear. Results: The results indicated an elevated odds ratio for tooth wear associated with age, sex, and smoking across all age groups. Among young patients, those using proton pump inhibitors and psychiatric medications had an elevated risk of tooth wear. Age, smoking, and diabetes conditions were associated with an increased odds ratio for marginal bone loss in all age groups. Psychiatric medications and sex elevated the odds ratio for marginal bone loss only among older patients. Conclusion: The results highlight the significant impact of age, sex, and smoking on tooth wear, and extend these risks to alveolar bone loss when combined with diabetes and psychiatric conditions. Parole chiave: alveolar marginal bone loss, risk factors, sex, tooth attrition

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. Parole chiave: 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. Parole chiave: 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. Parole chiave: 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.