Use of Narrow-Diameter Implants in Completely Edentulous Patients as a Prosthetic Option: A Systematic Review of the Literature.

OBJECTIVE: The objective of the present review is to assess the implant survival, marginal bone loss, and biomechanical features of narrow-diameter implants (2.5-3.5 mm) supporting or retaining full-arch fixed or removable restorations. MATERIALS AND METHODS: Three operators screened the literature (PubMed, Cochrane Library, and Google Scholar) and performed a hand search on the main journals that focus on implantology until 24 March 2019. Only articles that considered full-arch restorations supported or retained by narrow-diameter implants (2.5-3.5 mm) were considered if they have a minimum of 10 patients and a mean follow-up of at least 6 months. The outcome variables were survival of implants and marginal bone loss. The review was performed according to the PRISMA statements. Risk of bias assessment was evaluated. Failure rates were analyzed using random effect Poisson regression models to obtain the summary estimate of 5-year survival rate and marginal bone loss. RESULTS: A total of nine papers were finally selected, reporting a high survival rate of the implants. Eight studies focused only on the mandible while one study reported data from both mandible and maxilla. All studies reported on removable restorations; none focused on fixed rehabilitations. The estimated survival rate for 5 years of follow-up was calculated to be 92.25% for the implants. The estimated marginal bone loss after 5 years was calculated to be 1.40 mm. No study reported implant fractures. CONCLUSIONS: With the limitations of the present study, there is evidence that 2.5-3.5 mm narrow-diameter implants retaining a removable restoration can be a successful treatment in fully edentulous patients. No data on fixed restorations was available.

Systematic review of the survival rate and the biological, technical, and aesthetic complications of fixed dental prostheses with cantilevers on implants reported in longitudinal studies with a mean of 5 years follow-up.

OBJECTIVE: A systematic review was carried out to evaluate the success and survival rate of implants supporting cantilever prosthesis, as well as the incidence of technical and biological complications. MATERIAL AND METHODS: A MEDLINE search was conducted up to December 2011 for studies with a mean follow-up of 5 years or more. Two independent reviewers screened the retrieved articles and extracted the data independently. Data on survival, failure, mechanical/technical and biological complications were analyzed. RESULTS: One-hundred and sixty articles were selected as abstract. Only 18 underwent a full-text analysis and only six were included in the study. The estimated cumulative survival rate of implants supporting cantilevered prosthesis was 98.9% (95% CI: 97.4-99.5%), whereas ICFDP survival was estimated to be about 97.1% (95% CI: 90.1-99.2%). Implant failures before prosthetic delivery were not considered. Biological complications were estimated to be 5.7% (95% CI: 4.2-7.6%) at implant level after 5 years. Technical complications were analyzed: the most common complications were veneer fractures (5-year estimate: 10.1%; 95% CI: 3.7-16.5%) and abutment screw fractures (5-year estimate: 1.6%; 95% CI: 0.8-3.5%). Decementation and screw loosening were estimated to be at 5 years 5.9% (95% CI: 1.7-16.8%) and 7.9% (95% CI: 3.2-18.2%), respectively. Implant fracture was rare (5-year estimate: 0.7%; 95% CI: 0.1-4.7%); no framework fracture was reported. Radiographic bone level changes did not yield statistically significant differences. No aesthetic outcome was reported. CONCLUSIONS: ICFDPS can be considered a reliable treatment: the systematic review assessed that there is no increase in complication rate due to the presence of the cantilever.

The use of short dental implants in clinical practice: literature review.

When anatomic structures and ridge resorption limit the placement of a standard implant, the clinician can apply augmentation techniques or use short implants. A literature review was carried out to evaluate the differences in survival rate and the rational use of short implants. Electronic search (MEDLINE) and manual search have been performed to select papers from 2000 to 2008. Of all the inclusion criteria the most relevant were: 1) studies with data on short implants; 2) studies on humans; 3) prospective, longitudinal, retrospective and multicenter studies; 4) no restrictions were applied about study design; 5) no implant type selection was applied. Exclusion criteria were: 1) studies concerning treatment of patients with conditions possibly affecting survival or success rates of implant treatment; 2) studies concerning treatment of patients with non-treated periodontal disease; 3) implants placed in non-healed ridge, such as postextractive short implants. A total of 13 studies fulfilled the inclusion criteria. Most of the studies have reported different survival rate for short and standard implants. The difference is not significant. The recent literature have demonstrated a similar survival rate for short and standard implants. Older articles have demonstrated a lower survival rate for short implants. The treatment planning is a key factor for success in the use of short implants. Some of the parameters the clinician should consider are: 1) area to rehabilitate as well as bone quality; 2) length of the implant; 3) implant diameter; 4) type of implant and surface treatment; 5) crown to implant ratio of the final prostheses; 6) type of prostheses; 7) connection to other implants; 8) occlusal/ parafunctional load; 9) prosthetic complications. Although in the literature there are no studies that analyze short implant survival from the point of view of each key factors, it can be assumed that a careful treatment planning can lead the clinician to obtain a successful rehabilitation.

Marginal adaptation of full-coverage CAD/CAM restorations: in vitro study using a non-destructive method.

AIM: Marginal fit of full-coverage crowns is a major requirement for long term success of this kind of restorations. The purpose of the study was to verify the marginal adaptation of computer assisted design (CAD)/computer assisted manufacturing (CAM) crowns on prepared teeth and on plaster dies. METHODS: Four couples of materials: zirconia-ceramic veneering (DC-Zircon, DCS Dental, Allschwill, CH/Cercon S, Degussa, DeguDent GmbH, Hanau, Germany), fiber-reinforced composite-composite veneering (DC-Tell, DCS Dental/Gradia, GC Europe, LEuven, Belgium), titanium-ceramic veneering (DC Titan, DCS Dental/Tikrom, Orotig, Verona, Italy) and titanium-composite veneering (DC Titan, DCS Dental/Gradia, GC Europe) were evaluated following the guidelines provided by ADA specific #8. Five crowns were fabricated for each material. Marginal gap values were measured at four points (0 degrees, 90 degrees, 180 degrees and 270 degrees starting from the centre of the vestibular surface) around the finishing line, on prepared teeth and on plaster dies at each step of the fabrication process. Digital photographs were taken at each reference point and a computer software was used to measure the amount of marginal discrepancy in microm. Statistical analysis was performed using t test at 95 percent confidence interval. RESULTS: All the tested materials, except for fiber-reinforced composite, show a marginal adaptation within the limits of ADA specification (25-40 microm). The application of veneering material causes decay in marginal adaptation, except for fiber-reinforced composite. CONCLUSION: Within the limitations of this study, it was concluded that marginal fit of CAD/CAM restoration is within the limits considered clinically acceptable by ADA specification #8. From the results of this in vitro study, it can be stated that CAD/CAM crowns produced with DCS system show a marginal adaptation within the limits of ADA specific #8, therefore milled CAD/CAM crowns can be considered a good alternative to more traditional waxing-investing-casting technique.

Clinical peri-implant sounding accuracy in the presence of chronic inflammation of peri-implant tissues. Clinical observation study.

AIM: The aim of this study was to assess if the probing pocket depth is a reliable clinical parameter in the evaluation of the depth of the peri-implant sulci. In case of chronic inflamed peri-implant tissues, this evaluation is useful for understanding the level of bone resorption. METHODS: The study enrolled 22 patients. All of them were diagnosed for a peri-implantitis and were scheduled for a resective surgery with implantoplasty. During the surgery, a full thickness flap was raised and resective surgery was performed as well as an implantoplasty procedure. Peri-implant probing values before the surgery (PAL) were recorded, as were values of bone resorption after flap elevation (DIB), at all four sites around each implant (88 sites). RESULTS: The mean value of PAL calculated for all 88 sites was 5.67 mm (+/-1.46); the correspondent value of DIB was 6.37 mm (+/-1.81). In 52 sites out of 88 (59.1%) the values of PAL and DIB were exactly the same (maximum difference 0.5 mm). In only 10 cases (11.3%) the difference between PAL and DIB was >2 mm. The mean values for PAL and DIB were not statistically different. CONCLUSIONS: Authors have concluded that in case of chronic inflammation of peri-implant tissues, the probe reaches the bone pick, allowing the clinician to have reliable information on the actual bone resorption.

Renal vein thrombosis in a newborn with prothrombotic genetic risk factors.

Environmental and genetic risk factors interact to cause venous thromboembolism. Renal vein thrombosis in the newborn has been frequently associated with "risk factors" as catheters, surgery or trauma, but it has also been demonstrated a pathogenetic role of genetic prothrombotic risk factors, i.e. activated protein C resistance and FV Leiden. The treatment of neonatal venous thrombosis varies worldwide and different approaches have been proposed. We present a case of renal vein thrombosis in a female newborn with normal plasma levels of protein C, protein S and antithrombin III, but with her genotype characterized by the presence of three prothrombotic risk factors: factor V Leiden, methylentetrahydrofolate reductase and platelet glycoprotein IIIa polymorphisms. The treatment with recombinant tissue plasminogen determined complete thrombus dissolution.

(TA)8 allele in the UGT1A1 gene promoter of a Caucasian with Gilbert's syndrome.

BACKGROUND AND OBJECTIVE: Gilbert's syndrome, a chronic non-hemolytic unconjugated hyperbilirubinemia, is caused by a reduction in the activity of hepatic bilirubin UDP-glucuronosyltransferase (UGT1A1). This reduction has been shown to be due to a polymorphism in the promoter region of the UGT1A1 gene. The presence of seven thymine adenine (TA) repeats reduces the efficiency of transcription of the UGT1A1 gene. To elucidate the genetic background of a patient affected by Gilbert's syndrome, we collected blood samples from family members for the analysis of the A(TA)nTAA motif in the promoter region of the UGT1A1 gene. DESIGN AND METHODS: Analysis of the A(TA)nTAA motif in the promoter region of the UGT1A1 gene was performed by PCR. Estimation of UGT1A1 promoter containing the variable (TA) repeats was performed by using a luciferase reporter system. RESULTS: Three different genotypes were identified due to the presence of (TA)6, (TA)7 and (TA)8 repeats. The production of luciferase decreases in inverse relation to the number of repeats. INTERPRETATION AND CONCLUSIONS: The (TA)7 polymorphism, associated with Gilbert syndrome, is the only allele found up to now in white populations, while two other variants (TA)5 and (TA)8 have been identified in black populations. We describe here the first case of a subject affected by Gilbert's syndrome who is heterozygous for the (TA)8 allele in the promoter region of the UGT1A1 gene. This polymorphism, as well as the (TA)7 one, is associated with an increased level of bilirubin and a significant reduction of transcription activity of the UGT1A1 gene.