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Purpose: To investigate and analyze the effects of different prosthetic protocols under different loading and occlusal conditions on the survival rates of single implants immediately placed into fresh extraction sockets of maxillary or mandibular premolars with single-stage surgery. Materials and Methods: Patients needing replacement of a single premolar in the maxilla or mandible were included and randomly divided into three groups based on the different loading protocols: group 1 = healing abutment; group 2 = provisional crown left out of occlusion without functional loading; and group 3 = provisional crown in functional occlusion in maximum intercuspation without contact in excursions. The hypothesis was that single implants inserted into fresh extraction sockets and immediately connected to a temporary crown under functional loading would demonstrate survival rates comparable to single implants placed in the same conditions connected to a healing abutment or to an immediate temporary crown left out of occlusion. Results: A total of 112 patients were treated, and 126 implants were placed (92 in the maxilla and 34 in the mandible). After a mean follow-up of 2.5 years (range 1 to 5 years), there were no failures in groups 1 or 2. Two implants failed in group 3 (one in the maxilla, one in the mandible). The cumulative survival rate was 98.5% across all groups, with 100% in groups 1 and 2 and 95% in group 3. Statistical analysis showed that group 3 displayed a survival rate comparable to groups 1 and 2 (P = .08). Conclusion: Within the limitations of this study, no significant differences were found in terms of implant survival rates between implants inserted into fresh extraction sockets without loading vs with immediate nonfunctional or functional loading. [ABSTRACT FROM AUTHOR]

Purpose: Evidence suggests that maxillary sinus floor augmentation via a lateral approach can be performed without positioning a bone graft inside, when one or more implants can be placed simultaneously. The aim of this study was to test if the placement of a porcine cortical bone layer underneath the sinus membrane can increase bone formation and implant stability. Materials and Methods: One hundred seventy-two patients with posterior maxilla atrophy needing implant rehabilitation were selected. Two hundred six sinus augmentation procedures were performed via a lateral approach, and 295 implants were placed in the same session of the sinus elevation surgery. In all the surgeries, a porcine cortical bone layer was placed underneath the sinus membrane, without using any graft material. After 6 to 7 months of healing, the implants were uncovered, then restored with porcelain-fused-to-metal crowns and monitored with a followup of 1 to 5 years. Results: The implant cumulative success rate was 95.2%, while the residual bone crest height changed from 2.67 ± 1.11 mm to 12.54 ± 1.42 mm, with an increase of 9.87 mm on average. Marginal bone resorption was 0.83 mm on average after 1 year of loading, while the mean implant stability measured at the moment of implant placement and 6 to 7 months later increased from an implant stability quotient (ISQ) of 62.61 ± 5.7 to an ISQ of 70.07 ± 8.2. Conclusion: This study confirms the validity of the graftless sinus elevation surgery when simultaneous implant placement is performed. The use of a porcine cortical bone layer seems to increase, from a radiologic point of view, the amount of bone around the implants, reducing healing time, cost, and biologic complications for the patient. [ABSTRACT FROM AUTHOR]

The aim of this case series is to contribute to the better knowledge and management of the complex anatomical configurations of maxillary premolars with four canals. The paper explains the endodontic treatment of five maxillary premolars with four canals, with three buccal and one palatal orifices, in different patients. The cases report several approaches in the treatment of four-canal maxillary premolars including a conservative canal preparation with a hybrid shaping technique, endodontic microsurgery and the application of biomaterials. The use of an operating dental microscope, different operating strategies and the critical evaluation of radiographs are all necessary steps for the correct and safe endodontic management of these teeth. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study was to investigate quantitative histological examination of bone reconstructed with non-resorbable high-density polytetrafluoroethylene membrane (d-PTFE), left intentionally exposed in post extraction sockets grafted with anorganic bone material, and removed after four weeks, versus extraction and guided bone regeneration (GBR), performed two months later. Materials and Methods: This study was designed as a multicenter randomized controlled trial of parallel-group design. Patients were selected and consecutively treated in three centers in Italy. Patients randomly received intentionally exposed non-resorbable d-PTFE membrane (group A), or guided bone regeneration (group B), to treat post-extractive alveolar bone defects with implant-supported restorations. Outcomes were: the implant failure, any mechanical and biological complications, patient satisfaction, and qualitative and histomorphometric evaluation of the collected bone samples. Results: Eighteen patients were consecutively enrolled in the trial. Of these, six out of 18 patients were male. All the included patients were treated according to the allocated interventions, and no drop out occurred. No implant failure and no complications were experienced, and all the patients were fully satisfied with the function and aesthetic of their implant-supported restoration, without difference between groups. Morphological analysis revealed no sign of tissue reaction, such as fibrosis or necrosis. Regenerated bone was well mineralized in both groups, but it seemed more mature in group B than in group A. Three samples showed a minimal number of lymphocytes. Several blood vessels of small size occupied the medullary spaces, where the tissue resulted in more maturity, indicating the activity of the tissue in progress. The histomorphometric evaluation showed no statistically significant differences in the tissue volume fractions between the two groups of patients. Conclusions: With the limitation of the present study, buccal plate reconstruction with an intentionally exposed non-resorbable membrane is an effective and easy procedure for regenerating a resorbed buccal bone plate, reducing the need for guided bone regeneration. [ABSTRACT FROM AUTHOR]

Periapical implantitis (IPL) is an increasingly frequent complication of dental implants. The causes of this condition are not yet entirely clear, although a bacterial component is certainly part of the etiology. In this case series study, two approaches will be described: because of persistent IPL symptoms, a patient had the implant removed and underwent histological analysis after week 6 from implantation. The histomorphometric examination revealed a 35% bone-implant contact area involving the coronal two-thirds of the implant. The apical portion of the fixture on the other hand was affected by an inflammatory process detectable on radiography as a radiolucent area. The presence of a probable root fragment, detectable as an imprecise radiopaque mass in the zone where the implant was later placed, confirms the probable bacterial etiology of this case of IPL. On the other hand, in case number 2, the presence of IPL around the fixture was solved by surgically removing the implant apical third as well as the adjacent tooth apex. It may be concluded from our histological examination that removal of the apical portion of the fixture should be considered an effective treatment for IPL since the remaining implant segment remains optimally osseointegrated and capable of continuing its function as a prosthetic abutment. Careful attention, however, is required at the implantation planning stage to identify in advance any sources of infection in the edentulous area of interest which might compromise the final outcome. [ABSTRACT FROM AUTHOR]

Purpose: To compare immediate and delayed implant replacement at failed implant sites to evaluate the factors associated with early failure of second implants after replacement. Materials and methods: Data regarding early implant failure followed by replacement with another fixture in a private practice setting between 2003 and 2019 were analysed retrospectively. Early failure was defined as loss of the dental implant within 6 months of placement. The impact of patient-level (age, sex, diabetes, smoking history) and implant-level (timing of implant replacement, timing of prosthetic loading, bone grafting) variables on the early failure rate of second implants after replacement was evaluated. Due to the hierarchical structure of the data, a multivariate multilevel mixed-effects Poisson regression analysis was performed. Results: A total of 109 patients (63 men and 46 women) diagnosed with early implant failure at 124 implant sites were included in the present study. Fifty-eight implants were immediately replaced at the time of removal of the failed implant (test group), whereas 66 were replaced after a healing period of 2 to 4 months (delayed approach; control group). A total of 15 implants failed after replacement in 11 patients during the first 6 months of follow-up. Of these, nine failures (15.25%) occurred in seven patients (13.21%) after immediate replacement, and six (9.09%) occurred in four patients (7.02%) who underwent delayed replacement. No statistically significant differences were detected between the two groups (P = 0.431). Conclusions: No significant differences in implant survival at sites of previous failure were found according to the timing of implant replacement. Conflict-of-interest statement: The authors declare there are no conflicts of interest relating to this study. [ABSTRACT FROM AUTHOR]

Platform switching is a concept recently introduced in implant dentistry. It is intended to reduce the crestal bone loss that is commonly found around implants exposed to the oral environment. The aim of this study was to examine biopsy specimens to help explain the biologic processes occurring around a platform-switched implant. A mandibular implant was removed 2 months after placement because of prosthetic rehabilitation difficulties. The implant was then sectioned and subjected to histologic and histomorphometric analysis. An inflammatory connective tissue infiltrate was localized over the entire surface of the implant platform and approximately 0.35 mm coronal to the implant-abutment junction, along the healing abutment. A possible reason for bone preservation around a platform-switched implant may lie in the inward shift of the inflammatory connective tissue zone at the implant-abutment junction, which reduces its injurious effect on the alveolar bone. [ABSTRACT FROM AUTHOR]

This clinical and radiographic prospective study evaluated bone loss around two-piece implants that were restored according to the platform-switching protocol. One hundred thirty-one implants were consecutively placed in 45 patients following a nonsubmerged surgical protocol. On 75 implants, a healing abutment 1 mm narrower than the implant platform was placed at the time of surgery. On the remaining implants, a healing abutment of the same diameter as the implant was inserted. All implants were positioned at the crestal level. Clinical and radiographic examinations were performed prior to surgery, at the end of surgery, 8 weeks after implant placement, at the time of provisional prosthesis insertion, at the time of definitive prosthesis insertion, and 12 months after loading. The data collected showed that vertical bone loss for the test cases varied between 0.6 mm and 1.2 mm (mean: 0.95 ± 0.32 mm), while for the control cases, bone loss was between 1.3 mm and 2.1 mm (mean: 1.67 ± 0.37 mm). These data confirm the important role of the microgap between the implant and abutment in the remodeling of the peri-implant crestal bone. Platform switching seems to reduce peri-implant crestal bone resorption and increase the long-term predictability of implant therapy. [ABSTRACT FROM AUTHOR]

The clinical applicability and predictability of osseointegrated implants in healthy patients have been studied extensively. Although successful treatment of patients with medical conditions including diabetes, arthritis, and cardiovascular disease has been described, insufficient information is available to determine the effects of diabetes on the process of osseointegration. An implant placed and intended to support an overdenture in a 65-year-old diabetic woman was prosthetically unfavorable and was retrieved after 2 months. It was then analyzed histologically. No symptoms of implant failure were detected, and histomorphometric evaluation showed the bone-to-implant contact percentage to be 80%. Osseointegration can be obtained when implants with a dual-acid-etched surface are placed in properly selected diabetic patients. [ABSTRACT FROM AUTHOR]