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PURPOSE: The purpose of this study was to assess the precision at the implant interface of gold-machined UCLA-type abutments and computer-assisted design and manufacture (CAD/CAM) titanium abutments with both external-hexagonal connection and internal-hexagonal connection. MATERIALS AND METHODS: Fifteen gold-machined UCLA-type abutments with external-hexagonal connection, 15 gold-machined UCLA-type abutments with internal-hexagonal connection, 15 CAD/CAM titanium abutments with external-hexagonal connection, and 15 CAD/CAM titanium abutments with internal-hexagonal connection were produced. The rotational freedom of all the abutments was assessed to detect the precision of fit of each abutment on the top of the implant platform. Measurements of rotational freedom were compared among groups. The quantitative differences among groups were assessed using 1-way analysis of variance (alpha = .05). RESULTS: Significant differences relative to rotational freedom were not found among the 4 groups (P > .19). CONCLUSION: Both types of abutments (gold-machined UCLA-type and CAD/CAM titanium) consistently showed 1 degree of rotational freedom between the implant and abutment in both cases of external-hexagonal connection and internal-hexagonal connection. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to assess the precision at the implant interface of titanium, zirconia, and alumina Procera abutments with a hexagonal connection for single-tooth restorations. Materials and Methods: Twenty Procera abutments were produced with commercially pure titanium, 20 with zirconia, and 20 with alumina using computer-assisted design and manufacture (CAD/CAM). The rotational freedom of the abutments was assessed to detect the precision of fit of each abutment on the top of the implant hexagon. Results: Significant differences relative to rotational freedom were found between groups: the titanium group and the zirconia group did not differ significantly, but both demonstrated significantly smaller mean rotational freedoms than the alumina group (P < .05). Rotational freedom was less than 3 degrees for all abutments. Conclusions: The hexagonal misfit of the Procera abutment on the implant hexagon may be implicated in screw joint loosening. In the present study, all types of CAD/CAM Procera abutments consistently showed less than 3 degrees of rotational freedom in a situation where the abutment was connected to an implant by a hexagonal external connection. [ABSTRACT FROM AUTHOR]

An abstract is presented for the article "Cemented versus screw-retained implant-supported single-tooth crowns: A 4-year prospective clinical study."

An abstract is presented for a study on the accuracy of three techniques that are used for making multiple implant abutment impressions.

The purpose of this experimental study was to evaluate the effect of early orthodontic loading on the stability and bone-implant interface of titanium implants in a rabbit model. Twenty-four short threaded titanium fixtures were inserted in the calvarial mid-sagittal suture of 10 rabbits. Two weeks following insertion, 20 implants (test group) were subjected to continuous distalization forces of 150 g for a period of 8 weeks. The remaining four implants (control group) were left unloaded for the same follow-up interval. Clinically, all implants except for one test fixture were stable, and exhibited no mobility or displacement throughout the experimental loading period. Histologically, all stable implants were well-integrated into bone. No differences could be found between the pressure and tension surfaces of the test implants relative to bone quality and density within a range of 1000 μm from the fixture surface. Similarly, qualitative differences were not observed between the apical and coronal portions of test fixtures. Morphometrically, a mean percentage bone-to-implant contact of 76.00 ± 18.73 per cent was found at the test pressure sides, 75.00 ± 11.54 per cent at the test tension sides, and 68.00 ± 15.55 per cent at the control unloaded surfaces. No statistically significant differences in the percentage of bone-to-metal contact length fraction were found between test pressure surfaces, test tension surfaces, and unloaded control surfaces. Marginal bone resorption around the implant collar or immediately beneath it was found in roughly the same percentage of analysed sites in the test and control fixtures. In contrast, slight bone apposition was demonstrated at the implant collar on the test pressure surfaces, while no apposition ro resorption were observed in the test tension zones. This study suggests that short endosseous implants can be used as anchoring units for orthodontic tooth movement early in the post-insertion hea... [ABSTRACT FROM AUTHOR]

During the COVID-19 pandemic, immunosuppressed patients showed prolonged SARS-CoV-2 infections, with several studies reporting the accumulation of mutations in the viral genome. The weakened immune system present in these individuals, along with the effect of antiviral therapies, are thought to create a favourable environment for intra-host viral evolution and have been linked to the emergence of new viral variants which strongly challenged containment measures and some therapeutic treatments. To assess whether impaired immunity could lead to the increased instability of viral genomes, longitudinal nasopharyngeal swabs were collected from eight immunocompromised patients and fourteen non-immunocompromised subjects, all undergoing SARS-CoV-2 infection. Intra-host viral evolution was compared between the two groups through deep sequencing, exploiting a probe-based enrichment method to minimise the possibility of artefactual mutations commonly generated in amplicon-based methods, which heavily rely on PCR amplification. Although, as expected, immunocompromised patients experienced significantly longer infections, the acquisition of novel intra-host viral mutations was similar between the two groups. Moreover, a thorough analysis of viral quasispecies showed that the variability of viral populations in the two groups is comparable not only at the consensus level, but also when considering low-frequency mutations. This study suggests that a compromised immune system alone does not affect SARS-CoV-2 within-host genomic variability.

Importance: In this work, we demonstrate the epidemiologic relevance of the Aeromonas genus as the cause of infective diarrhea in North East Italy, both in children and adult subjects, with the significative presence of highly pathogenic strains. Aeromonas strains possess a heterogeneous armamentarium of pathogenicity factors that allows the microbe to affect a wide range of human intestinal epithelial cell processes that justify the ability to induce diarrhea through different mechanisms and cause diseases of variable severity, as observed for other gastrointestinal pathogens. However, it remains to be determined whether specific genotype(s) are associated with clinical pictures of different severity to implement the diagnostic and therapeutic approaches for this relevant enteric pathogen., Competing Interests: The authors declare no conflict of interest.

In this paper, we have described cases of nocardiosis that occurred in our hospital and examined the literature on other nocardiosis cases recorded in Italy. We have collected the clinical details of our recent cases and described them in full. Regarding the older cases in our hospital and the Italian cases present in the literature, we noted the clinical data, the Nocardia species involved, and the antimicrobial susceptibility reported. The survey was carried out on PubMed. The first of our cases is an elderly woman with compromised health who had a lung and bloodstream infection. A second case is a middle-aged man who developed an infection in the thigh. A third patient is a middle-aged man on immunosuppressive therapy who developed a cerebral abscess. Our review shows that patients are usually immunocompromised, with an average age of 60 years, and more frequently males. The most affected organs are the lungs and the brain, and the most reported species is Nocardia farcinica. Antimicrobial susceptibility tests show good efficacy of linezolid, cotrimoxazole and amikacin. We conclude that, if a Nocardia infection is suspected, the most likely species to be considered in Italy is N. farcinica. In addition, if empirical therapy is needed, we suggest relying on linezolid, cotrimoxazole or amikacin.

Purpose: Primary stability is a key factor for successful implant osseointegration, especially in poor bone quality and early/immediate loading. In the immediate loading protocol, insertion torque values (ITVs) have been suggested to be the most valid prognostic factor for osseointegration of maxillary implants. The objectives of this study were to: (1) evaluate ITVs achieved by a variable-thread tapered implant in the posterior maxilla; and (2) assess the impact of bone quality, implant dimensions, bicortical anchorage, and implant location on ITVs., Materials and Methods: Twenty-six adult, systemically healthy patients received 173 variable-thread tapered implants in maxillary premolar and molar healed edentulous sites with a minimum subsinus height of 8 mm. Implant sites were prepared using the bone-quality adjusted drilling sequence according to manufacturer's recommendations. Bone quality was recorded subjectively during drilling based on Misch criteria (D1-D4), and ITVs were measured with a manual torque wrench. Univariate and multivariate analyses were performed at the 0.05 significance level., Results: First and second molar sites accounted for 46.8% of all implants. D4 bone was encountered in 61.3% of the sites. Most of the implants were 4.3 mm in diameter (59.5%), and lengths of 11.5 and 13 mm were most commonly used (75.2%). Approximately half of the implants were associated with apical cortical anchorage (51.4%). The overall mean ITV was 44.5 ± 23.0 Ncm, with 65.5 ± 15.6 Ncm, 55.5 ± 19.6 Ncm, and 36.6 ± 21.7 Ncm for D2, D3, and D4 bone, respectively. Bone quality and implant location significantly affected ITVs, while implant dimensions and apical cortical anchorage did not., Conclusions: ITVs of variable-thread implants were significantly influenced by variations in bone quality and implant position in the posterior maxilla. Despite the influence of bone quality on primary stability, the mean ITVs attained with variable-thread tapered implants in poor bone quality were within the recommended range for immediate loading., (© 2018 by the American College of Prosthodontists.)

Purpose: To compare the 3-year outcomes of immediately loaded and one-stage conventionally loaded variable-thread tapered implants in the posterior maxilla., Materials and Methods: This study was designed as a split-mouth randomised controlled trial. Twenty-six patients attending the postgraduate Periodontics Department at the Lebanese University, and missing teeth bilaterally in the posterior maxilla were randomised. All patients received three to four implants in each of the posterior sextants. The implants on one side were immediately loaded with a provisional resin fixed partial denture on definitive multi-unit abutments regardless of their primary stability. The implants in the contralateral side received definitive multi-unit abutments according to the one-stage unloaded protocol. Three to 3.5 months following implant placement, the implants were restored with metal-ceramic fixed prostheses. Outcome measures were implant and prosthesis failure rates, complications, and peri-implant bone level changes up to 3 years following delivery of the definitive prosthesis. The clinical outcomes and radiographic measurements were performed by a single outcome assessor blinded to the type of interventions., Results: Two patients dropped out prior to the delivery of definitive prostheses. The results were analysed using a per-protocol analysis and included 24 patients. Four implants supporting a four-unit immediately loaded prosthesis failed in one patient, 3 months following definitive prosthesis. In the same patient, the three contralateral conventionally loaded implants failed 14 months after definitive prosthesis. There were no significant differences in the proportions of implant and prosthesis failures at 3 years (difference = 0%; 95% CI 0.0% to 14.2%; P = 0.999). Peri-implantitis was diagnosed at two adjacent conventionally loaded implants in one patient at the 3-year examination. In the immediately loaded group, four early minor prosthetic complications occurred during the provisionalisation phase. Following delivery of the definitive prostheses, one minor ceramic fracture was observed in each of the implant groups. The difference in the rate of complications between the two interventions was not statistically significant at 3 years (difference = 13%; 95% CI 3.4% to 27.7%; P = 0.453). The 3-year peri-implant marginal bone level changes were evaluated in 23 patients (77 immediately loaded and 76 conventionally loaded implants). On average, patients lost 0.79 (0.62) mm at the immediately loaded and 0.91 (0.82) mm at the conventionally loaded implants, the difference being statistically not significant (difference = 0.12 mm; 95% CI -0.31 to 0.55 mm; P = 0.590). The 3-year marginal bone level changes were not significantly different between smokers (n = 12) and non-smokers (n = 11) (difference = 0.19 mm; 95% CI -0.24 to 0.62 mm; P = 0.382)., Conclusions: Immediate loading of three- to four-unit fixed partial prostheses supported by variable-thread implants in the posterior maxilla can achieve similar 3-year results to one-stage conventionally loaded implants., Competing Interests: Conflict of interest statement: This study was independently designed by the investigators but was supported by Nobel Biocare Services, Kloten, Switzerland (grant number 2010-954) in the form of free surgical kits, implants and prosthetic components. No other financial contribution was received by any of the authors or their institutions. The authors declare that there is no affiliation or any other conflict of interest to the sponsor and that Nobel Biocare did not in any way interfere with the conduct of the trial or the publication of its results.

Purpose: To compare the outcome of immediately loaded and one-stage conventionally loaded variable-thread tapered implants in the posterior maxilla., Materials and Methods: This study was designed as a split-mouth randomised controlled trial. Twenty-six patients missing teeth bilaterally in the posterior maxilla received three to four implants in each of the posterior sextants. Bone quality was recorded based on Misch criteria (D1-D4) and insertion torque values were measured using a manual wrench. The implants on one side were immediately loaded with a temporary resin fixed partial denture on definitive multi-unit abutments. The implants in the contralateral side received definitive multi-unit abutments according to the one-stage unloaded protocol. Three to 3.5 months following implant placement, the implants were restored with metal-ceramic fixed prostheses. Outcome measures were implant and prosthesis failure rates, complications, and peri-implant bone level changes at 1 year following delivery of the definitive prostheses., Results: Two patients dropped out prior to the delivery of definitive prostheses. Four implants supporting a four-unit immediately loaded prosthesis failed in one patient, 3 months following delivery of the definitive prostheses. None of the conventionally loaded implants or prostheses failed. There were no significant differences in the proportions of implant and prosthesis failures (difference = 4.2%; 95% CI -4.2 to 12.6%; P = 0.999). In the immediately loaded group, four early prosthetic complications occurred during the provisionalization phase (three small resin chippings and one prosthetic screw loosening). No other complications were reported. The difference in the rate of complications between the two interventions was not statistically significant (difference = 16.7%; 95% CI -1.2% to 35.6%; P = 0.125). The 1-year peri-implant marginal bone level changes were evaluated in 23 patients (77 immediately loaded and 76 conventionally loaded implants). On average, patients lost 0.42 mm at the immediately loaded and 0.46 mm at the conventionally loaded implants, the difference being statistically not significant (difference = 0.044 mm; 95% CI -0.27 to 0.18 mm; P = 0.701)., Conclusions: Immediate loading of 3- to 4-unit fixed partial prostheses supported by variable-thread implants in the posterior maxilla can yield good and similar 1-year results to one-stage conventionally loaded implants., Competing Interests: Conflict-of-interest statement: This study was independently designed by the investigators but was supported by Nobel Biocare Services AG, Kloten, Switzerland (grant number 2010-954) in the form of free surgical kits, implants and prosthetic components. No other financial contribution was received by any of the authors or their institutions. The authors declare that there is no affiliation or any other conflict of interest to the sponsor and that Nobel Biocare did not in any way interfere with the conduct of the trial or the publication of its results.

Purpose: The purpose of this prospective clinical study was to compare titanium and gold-alloy abutments when used with cemented, implant-supported single-tooth crowns. For 4 years following prosthodontic rehabilitation, these abutments were evaluated with respect to peri-implant marginal bone levels and peri-implant soft tissue parameters., Materials and Methods: During the years 1998 to 2000, 20 patients were selected from a patient population receiving treatment in the Implantology Department at the University of Padova, Italy. They all presented with single-tooth bilateral edentulous sites in the premolar/molar region with adequate bone width, similar bone height on each side, and an occlusal scheme that allowed for the establishment of identical occlusal cusp/fossa contacts on each side. Each subject received two identical implants (one in each edentulous site). One was randomly selected to be restored with a titanium abutment and a cemented implant-supported single-tooth crown, and the other was restored with a gold-alloy abutment and a cemented implant-supported single tooth crown. Data on peri-implant marginal bone levels and soft tissue parameters were collected for 4 years after abutment and crown insertion placement and analyzed to determine whether there was a significant (p< .001) difference with respect to the type of abutments (titanium vs. gold alloy) used., Results: All subjects completed the study. All 40 implants survived, resulting in a cumulative implant success rate of 100%. Statistical analysis revealed no significant differences between the two groups with respect to peri-implant marginal bone levels and soft tissue parameters., Conclusions: Within the limitations of this study, the results indicate that there was no evidence of different response with the peri-implant marginal bone and soft tissue when titanium or gold-alloy abutments were used in conjunction with the cemented, single-tooth implant restorations provided for this limited patient population. There was no evidence of different behavior of peri-implant marginal bone and of peri-implant soft tissue when titanium abutments or gold-alloy abutments were used for cemented single-tooth implant restorations in this limited patient population.

Human histologic evidence of periodontal regeneration following treatment of intrabony defects with enamel matrix derivative has yielded inconsistent results in recent case reports. A 46-year-old woman presenting one deep intrabony defect at the distal root of a mandibular first molar scheduled for extraction was selected for enamel matrix derivative therapy. During surgery, a notch was placed at the most apical level of calculus on the experimental root. Nine months postsurgery, a block section including the distal root and surrounding periodontal tissues was obtained and processed in a mesiodistal plane. Histologic analysis demonstrated two different patterns of healing along the proximal and furcal surfaces. Regeneration with new cellular cementum, bone, and periodontal ligament with functional fiber orientation was observed on the distal aspect of the root, whereas the furcal surface healed through ankylosis. This report underlines the biologic variability in wound healing following enamel matrix derivative therapy in periodontal intrabony defects and within the same defect. Host-specific intrinsic and/or extrinsic factors accounting for this variability remain to be investigated.

Purpose: This in vitro study evaluated the accuracy of master casts obtained by using (1) copings modified by sandblasting and coating their roughened surfaces with impression adhesive before final impression procedures and (2) gold machined UCLA abutments as impression copings in final impression procedures for single-tooth implant replacement cases., Materials and Methods: A polymeric resin model with a standard single implant was used to simulate a clinical situation. A group of 20 impressions were made using square impression copings sandblasted to roughen their external surfaces at a supragingival level and then coated with Impregum polyether adhesive; a second group of 20 impressions were made using gold machined UCLA abutments as impression copings. The castable part of the UCLA abutments was secured with resin to the gold machined section of the UCLA abutment to prevent movement of the castable part itself on the gold machined portion during the impression procedures; the castable portion of the UCLA was also coated with the Impregum polyether adhesive to improve the stability of the gold machined UCLA abutment inside the impression material. Master casts fabricated for both groups were analyzed to detect rotational position change of the hexagon on the implant replicas in the master casts with reference to the resin model., Results: The rotational position changes of the hexagon on implant replicas were significantly less variable in the master casts obtained using gold machined UCLA abutments as impression copings than in the master casts achieved with the roughened square impression copings., Discussion: Improved precision of the impression was achieved when the gold machined UCLA abutments were used as impression copings., Conclusion: This report suggests that using gold machined UCLA abutments as impression copings in the final impression procedures can enable the clinician to achieve a more accurate orientation of the implant replicas in the laboratory master casts for single-tooth implant replacement cases.

Purpose: Laboratory processing of implant-supported prostheses may alter the surface of the abutment in contact with the implant head, with potential repercussions for the interface fit. The purpose of this study was to assess changes at the implant interface of high-strength zirconia ceramic esthetic abutments with a hexagonal connection (ZiReal; 3i/Iimplant Innovations, Palm Beach Gardens, FL) following abutment preparation for single-tooth restorations., Materials and Methods: The depth (d) and width (w) of the titanium hexagonal portion of the abutment, the apical diameter of the abutment (D), and the rotational freedom (R) of the abutment were assessed for 20 ZiReal abutments prior to preparation (time 0) and following abutment preparation (time 1) to detect any eventual change of fit of the abutment on the top of the implant hexagon., Results: No significant differences relative to any study parameter (d, w, D, and R) were observed between time 0 and time 1 (P = .9542)., Discussion and Conclusions: The hexagonal misfit of the titanium machined ZiReal abutment on the implant hexagon may be implicated in screw joint loosening. The results of this report suggest that if all laboratory steps are carefully observed, changes at the implant/ZiReal abutment do not occur. The maintenance of the original features of the ZiReal abutment may reduce the risk of screw loosening.