Marginal bone changes around platform-switched conical connection implants placed 1 or 2 mm subcrestally: A multicenter crossover randomized controlled trial

AbstractIntroduction:This study analyzes early marginal bone modifications occurring aroundplatform-switched implants with conical connection placed 1 or 2 mm subcrestally.Methods:This crossover randomized controlled trial enrolled partially edentulouspatients needing two implants in either the posterior maxilla or mandible. Eachpatient received two platform-switched implants with conical connection inserted2 mm (Test) and 1 mm (Control) subcrestally. Definitive abutments were immediatelyconnected and, after 4 months of unsubmerged healing, screwed metal-ceramiccrowns were delivered. Radiographs were taken at implant placement (T0), prosthesisdelivery (T1), and after 1 year of prosthetic loading (T2).Results:Fifty-one patients (25 males and 26 females; mean age 61.2 ± 12.1 years)totaling 102 implants were included in the final analysis. Mean peri-implant bonelevel (PBL) reduction from T0 to T2 was not significantly different around Test (0.49± 0.32 mm) and Control implants (0.46 ± 0.35 mm;p=0.66). Multivariate linearregression models highlighted a significant positive correlation between history ofperiodontitis and PBL reduction. At T2, no Test group implant and 6 Control groupimplants exhibited PBL below the implant platform (11.8% of Control groupimplants).Conclusion:No significant differences in peri-implant marginal bone changes weredemonstrated after 1 year of prosthetic loading between platform-switched implantswith conical connection inserted either 1 or 2 mm subcrestally. However, 2 mm sub-crestal placement resulted in deeper implant positioning at T2, with no exposure oftreated implant surface and potential preventive effect against subsequent peri-implant pathology

ATHENA detector proposal - a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider

ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity.This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges

ATHENA detector proposal — a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider

ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges

Clinical, histologic and histomorphometric analyses of regenerated bone in maxillary sinus augmentation using fresh frozen human bone allografts.

BACKGROUND: The purpose of the present study was the clinical and the histologic evaluation of fresh frozen human bone (FFB) allografts used for maxillary sinus-augmentation procedures. METHODS: Ten subjects were treated with maxillary sinus augmentations using FFB. Radiologic measurements were recorded on computed tomography scans preoperatively and 5 months after the sinus surgeries. At 5 months, during implant placement, 10 core biopsies were retrieved and processed for histomorphometric evaluation under light microscopy (LM). Clinical and histomorphometric measurements are presented as mean +/- SD. RESULTS: At baseline, the height of the alveolar ridge measured 4.3 +/- 1.3 mm (mean); after augmentation procedures, at implant positioning, it had a mean height of 16.0 +/- 1.8 mm. All 22 dental implants were clinically healthy after 5 months. LM showed that most of the specimens presented newly formed bone that was completely integrated with preexisting bone. The interface areas between new and old bone were not discernible. Woven bone was present in some areas of the biopsies; however, in the majority of the examined regions, there was mature osseous tissue presenting features of trabecular bone. There was no evidence of an acute inflammatory infiltrate. Histomorphometry revealed that the percentage of bone was 48.15% +/- 14.32%, whereas marrow spaces occupied the rest of the area. CONCLUSION: FFB is a biocompatible material that can be successfully used for maxillary sinus augmentations without interfering with normal reparative bone processes

Clinical, histologic and histomorphometric analyses of regenerated bone in maxillary sinus augmentation using fresh frozen human bone allografts

Background: The purpose of the present study was the clinical and the histologic evaluation of fresh frozen human bone (FFB) allografts used for maxillary sinus-augmentation procedures. Methods: Ten subjects were treated with maxillary sinus augmentations using FFB. Radiologic measurements were recorded on computed tomography scans preoperatively and 5 months after the sinus surgeries. At 5 months, during implant placement, 10 core biopsies were retrieved and processed for histomorphometric evaluation under light microscopy (LM). Clinical and histomorphometric measurements are presented as mean SD. Results: At baseline, the height of the alveolar ridge measured 4.3 +/- 1.3 mm (mean); after augmentation procedures, at implant positioning, it had a mean height of 16.0 +/- 1.8 mm. All 22 dental implants were clinically healthy after 5 months. LM showed that most of the specimens presented newly formed bone that was completely integrated with preexisting bone. The interface areas between new and old bone were not discernible. Woven bone was present in some areas of the biopsies; however, in the majority of the examined regions, there was mature osseous tissue presenting features of trabecular bone. There was no evidence of an acute inflammatory infiltrate. Histomorphometry revealed that the percentage of bone was 48.15% +/- 14.32%, whereas marrow spaces occupied the rest of the area. Conclusion: FFB is a biocompatible material that can be successfully used for maxillary sinus augmentations without interfering with normal reparative bone processes

Primary stability of short implants inserted using piezoelectric or drilling systems: An in vitro comparison

The primary objective of the present in vitro study was to evaluate the influence of implant site preparation technique (drills vs ultrasonic instrumentation) on the primary stability of short dental implants with two different designs inserted in simulated low-quality cancellous bone. Eighty implant sites were prepared in custom-made solid rigid polyurethane blocks with two different low cancellous bone densities (5 or 15 pounds per cubic foot [PCF]), equally distributed between piezoelectric (Surgysonic Moto, Esacrom, Italy) and conventional drilling techniques. Two short implant systems (Prama and Syra, Sweden & Martina) were tested by inserting 40 fixtures of each system (both 6.0 mm length and 5.0 mm diameter), divided in the four subgroups (drills/5 PCF density; drills/15 PCF density; piezo/5 PCF density; piezo/15 PCF density). Insertion torque (Ncm), implant stability quotient values, removal torque (Ncm), and surgical time were recorded. Data were analyzed by 3-way ANOVA and Scheff\ue9\u2019s test (a \ubc 0.05). With slight variations among the considered dependent variables, overall high primary implant stability was observed across all subgroups. Piezoelectric instrumentation allowed for comparable or slightly superior primary stability in comparison with the drilling procedures in both implant systems. The Prama implants group showed the highest mean reverse torque and Syra implants the highest implant stability quotient values. Piezoelectric implant site preparation took prolonged operative time compared to conventional preparation with drills; among the drilling procedures, Syra system required fewer surgical steps and shorter operative time

The impact of graft remodeling on peri-implant bone support at implants placed concomitantly with transcrestal sinus floor elevation: A multicenter, retrospective case series

Objectives: To evaluate the impact on peri-implant bone support (as assessed on periapical radiographs) of the remodeling dynamics of varying graft biomaterials used for transcrestal sinus floor elevation (tSFE). Methods: The study is a multicenter, retrospective series of cases undergone tSFE (performed according to the Smart Lift technique) and concomitant implant placement. At operator's discretion, tSFE was performed with bone core (BC) alone or supplemented by deproteinized bovine or porcine bone mineral (DBBM and DPBM, respectively), synthetic hydroxyapatite in a collagen matrix (S-HA), or ß-tricalcium phosphate (ß-TCP). Immediately after surgery, at 6–12 months post-surgery, and at later (≥24 months) follow-up intervals, the percentage proportion of the implant surface in direct contact with the radiopaque area was calculated for the entire implant surface (totCON%). Also, the height of the graft apical to the implant apex (aGH) was assessed. Results: At 6–12 months following tSFE, median totCON% was 100%, with a median aGH of 1.4 mm. A tendency of aGH to decrease in height was observed at later follow-up intervals for sites treated with all grafting procedures. In all treatment groups, the majority of the implant surface was still surrounded by the radiopaque area at the longest follow-up visits. Conclusions: Although the height of the peri-implant radiopaque area apical to the implant apex tends to reduce overtime at sites which have received tSFE, the peri-implant bone support seems to be maintained long term irrespective of the graft material used

Changes in implant stability using different site preparation techniques: osseodensification drills versus piezoelectric surgery. A multi-center prospective randomized controlled clinical trial

Introduction: Implant stability is influenced by bone density, implant design, and site preparation characteristics. Piezoelectric implant site preparation (PISP) has been demonstrated to improve secondary stability compared with conventional drilling techniques. Osseodensification drills (OD) have been recently introduced to enhance both bone density and implant secondary stability. The objective of the present multi-center prospective randomized controlled trial was to monitor implant stability changes over the first 90 days of healing after implant bed preparation with OD or PISP. Methods: Each patient received two identical, adjacent or contralateral implants in the posterior maxilla. Following randomization, test sites were prepared with OD and control sites with PISP. Resonance frequency analysis was performed immediately after implant placement and after 7, 14, 21, 28, 60, and 90 days. Implants were then restored with single screw-retained metal-ceramic crowns and followed for 12 months after loading. Results: Twenty-seven patients (15 males and 12 females; mean age 63.0 ± 11.8 years) were included in final analysis. Each patient received two identical implants in the posterior maxilla (total = 54 implants). After 1 year of loading, 53 implants were satisfactorily in function (one failure in test group 28 days after placement). Mean peak insertion torque (40.7 ± 12.3 Ncm and 39.5 ± 10.2 Ncm in test and control group, respectively) and mean implant stability quotient (ISQ) value at baseline (71.3 ± 6.9 and 69.3 ± 7.6 in test and control group, respectively) showed no significant differences between the two groups. After an initial slight stability decrease, a shift to increasing ISQ values occurred after 14 days in control group and after 21 days in test group, but with no significant differences in ISQ values between the two groups during the first 90 days of healing. Conclusion: No significant differences in either primary or secondary stability or implant survival rate after 1 year of loading were demonstrated between implants inserted into sites prepared with OD and PISP