Maxillary bone augmentation with calvarial bone graft for immediate full-arch rehabilitation: Insights from a 10-year proof-of-concept retrospective analysis.

OBJECTIVE: Evaluate the long-term outcomes of full-arch rehabilitation using immediate dental implant placement and continuous functional loading with full-fixed dental prostheses (FFDPs). MATERIALS AND METHODS: Fifty-six patients received temporary implants (n = 327) at maxillary augmentation with calvarial bone. A provisional acrylic FFDP was immediately loaded onto these implants. After 6 months, the temporary implants were replaced with definitive implants (n = 326) and immediately loaded with a second provisional FFDP (N = 55). Subsequently, a baseline radiograph was taken following a 6-month healing period. The second bridge was then substituted with a definitive FFDP. Primary outcomes included peri-implant marginal bone level (MBL) and definitive implant survival. Secondary outcomes evaluated provisional implant and prostheses survival, complications, and patient satisfaction. RESULTS: The provisional implants had a survival rate of 97.9%. One patient was excluded from further analysis due to loss of temporary implants and first FFDP. The definitive implant survival rate after 10 years was 92.2%, with a moderate but significant decrease in MBL between baseline radiography and 10 years later (-0.08 ± 0.18 vs. -0.24 ± 0.44). However, large individual variations were observed, with 65.8% of implants showing no bone loss and 9.2% showing loss ≥0.5 mm. Sinusitis was experienced by 14.3% of patients upon surgery. Patient satisfaction was high or reported no issues after protocol completion (80%). One patient lost all six definitive implants and definitive FFDP 8.2 years after implant placement. CONCLUSIONS: The described protocol can be regarded as a long-term, highly successful method for full-arch rehabilitation of atrophied maxillae while enabling continuous masticatory and speaking functionality.

One-stage prosthodontically driven jaw reconstruction in patients with benign and malignant pathologies: A 7- to 11-year cohort study.

OBJECTIVES: One stage functional jaw reconstruction is defined as the resection and reconstruction of segmental defects in conjunction with the placement of dental implants in an ideal prosthetic position and loaded with a provisional restoration, during one surgical procedure. The aim of the study is to describe clinical outcomes of patients who underwent one stage functional jaw reconstruction. METHODS: Patients who underwent one-stage functional jaw reconstruction, from January 2013 to March 2016 were recalled in 2022 and 2023. Planning and execution for the reconstruction utilized either analogue or digital techniques. Outcome parameters recorded were treatment-related outcomes at patient level, implant-related outcomes and patient-reported outcome measures. RESULTS: Eighteen patients underwent one-stage jaw reconstruction with a total of 57 implants. Four patients had maxillary and 14 had mandibular reconstructions. Ten patients underwent postoperative radiotherapy. Ten patients were planned using analogue and eight by digital planning. Three patients had partial flap necrosis, three patients had plate fractures, implant loss was seen in one patient and four patients died during the period. A functional prosthesis was provided in 16 out of the 18 patients. CONCLUSION: One-stage functional jaw reconstruction is a predictable method for providing rehabilitation with successful outcomes at 7-11 years. However, caution should be exercised when the treatment modality is carried out in patients with malignant pathologies who have undergone radiotherapy.

Comparative in vitro evaluation of microgap in titanium stock versus cobalt-chrome custom abutments on a conical connection implant: Effect of crown cementation and ceramic veneering.

OBJECTIVE: To compare the implant-abutment connection microgap between computer-aided design and computer-aided manufacturing (CAD/CAM) milled or laser-sintered cobalt-chrome custom abutments with or without ceramic veneering and titanium stock abutments with or without crown cementation. MATERIAL AND METHODS: Six groups of six abutments each were prepared: (1) CAD/CAM cobalt-chrome custom abutments: milled, milled with ceramic veneering, laser-sintered, and laser-sintered with ceramic veneering (four groups: MIL, MIL-C, SIN, and SIN-C, respectively) and (2) titanium stock abutments with or without zirconia crown cementation (two groups: STK and STK-Z, respectively). Abutments were screwed to the implants by applying 30 Ncm torque. All 36 samples were sectioned along their long axes. The implant-abutment connection microgap was measured using scanning electron microscopy on the right and left sides of the connection at the upper, middle, and lower levels. Data were analyzed using the Kruskal-Wallis test (p < .05). RESULTS: Mean values (µm) of the microgap were 0.54 ± 0.44 (STK), 0.55 ± 0.48 (STK-Z), 1.53 ± 1.30 (MIL), 2.30 ± 2.2 (MIL-C), 1.53 ± 1.37 (SIN), and 1.87 ± 1.8 (SIN-C). Although significant differences were observed between the STK and STK-Z groups and the other groups (p < .05), none were observed between the milled and laser-sintered groups before or after ceramic veneering. The largest microgap was observed at the upper level in all groups. CONCLUSIONS: Titanium stock abutments provided a closer fit than cobalt-chrome custom abutments. Neither crown cementation nor ceramic veneering resulted in significant changes in the implant-abutment connection microgap.

An in vitro study using confocal laser scanning microscopy to evaluate the marginal misfits of different implant-supported frameworks.

PURPOSE: This study aimed to develop and evaluate a simple, non-destructive method for assessing the misfit and passivity of implant-retained prostheses frameworks. MATERIALS AND METHODS: To simulate the rehabilitation of a mandible posterior partially edentulous area using 3-unit screw-retained frameworks supported by two implants were fabricated and divided into the following five groups (n = 10 in each group): OP = one-piece framework cast in Co-Cr with the conventional method (control-group); Co-Cr frameworks sectioned and welded by laser (=LAS) or tungsten inert gas (=TIG); Co-Cr CAD-CAM = milled Co-Cr framework; Zir CAD-CAM = milled zirconia framework. The horizontal |X| and vertical |Y| misfits were measured using confocal laser scanning microscopy with one or both screws tightened. Data were analyzed by a two-way ANOVA with repeated measures and Bonferroni correction (α = 0.05). RESULTS: The greatest |X| misfit was observed in the OP group with both screws tightened (290 µm) and one screw tightened (388 and 340 µm). The conventional casting groups sectioned and welded by laser or TIG had lower mean values (235.35 µm, both screws tightened; and 275 µm, one screw tightened) than the OP framework. However, these values still exceeded those of the milled Co-Cr and zirconia frameworks (190 and 216 µm with both screws tightened). Across all reading conditions, every framework subjected to testing consistently maintained vertical |Y| misfit levels below the threshold of 53 µm; however, the milled frameworks exhibited higher vertical misfits than the frameworks obtained by the conventional cast method. CONCLUSIONS: The frameworks, whether cast and sectioned with laser welding or milled from Co-Cr, exhibit improved marginal misfit and enhanced passive fit when compared to other fabrication methods. Additionally, the use of confocal laser scanning microscopy is highly effective for passivity and misfit analysis.

The effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis: A retrospective study.

PURPOSE: The objective of this retrospective study was to evaluate the effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis. MATERIAL AND METHODS: Records of 96 patients and 148 external hexagon (EH) implants with time in function ranging from 1 to 17 years were included in the study. The most recent clinical and radiographic data were collected from records and the prevalence of peri-implantitis was defined according to the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions. Marginal bone level (MBL), emergence angle (EA), emergence profile (EP), and crown/implant platform horizontal ratio (CIHR) were obtained from periapical radiographs. Dichotomous variables at the patient- and implant level were compared with association tests. Mann-Whitney U-Test was performed to compare continuous quantitative values between the studied groups. Binomial logistic regression was conducted to identify risk indicators associated with the peri-implantitis event at the patient- and implant level, with the significance level set at 5% for all tests. RESULTS: Nineteen patients (19.2%) and 24 implants (16.2%) with a mean time in function of 5.0 ± 4.7 years were classified as having peri-implantitis. No statistically significant differences concerning gender, mean age, implant location in the jaw, or time in function were observed between patients with or without peri-implantitis (p > 0.05). Of 24 implants with peri-implantitis 10 (41.7%) displayed EA ≤ 30° (16.4%) while 14 (58.3%) presented EA > 30° with no statistical difference between the groups (p > 0.05). No statistically significant associations were identified between EA, EP, or CIHR and the prevalence of peri-implantitis. CONCLUSION: The findings seem to indicate that the EA, EP, and CIHR of single restorations over external hexagon implants are not associated with the presence of peri-implantitis. However, prospective studies with larger samples are required to better ascertain such an association in the long term.

Association between smoking and peri-implant diseases: A retrospective study.

OBJECTIVES: To determine the association between tobacco and peri-implant diseases in a sample of patients who had received implant-supported restorations in a university dental clinic. Furthermore, the study aimed to investigate patient- and implant-related variables associated with peri-implant diseases. MATERIALS AND METHODS: The present retrospective study analyzed data from 117 patients treated with implant-supported restorations from 2001 to 2013. A total of 450 implants were evaluated. Patients were selected from an electronic database, and patient- and implant-related variables were evaluated. Detailed information regarding the smoking history (i.e., smoking status, lifetime cumulative dose, duration of exposure, intensity of the habit, and smoking cessation) was recorded. The primary study outcome was peri-implant status [i.e., health (H), peri-implant mucositis (PM) and peri-implantitis (PI)]. Univariate and multinomial regression models comparing PM and PI versus peri-implant health were conducted. RESULTS: A total of 117 subjects [55 (47%) females and 62 (53%) males] with a mean age at examination of 64.2 years (SD 11.6) and rehabilitated with 450 implants were included. The average number of implants per patient was 4.6 (SD 3.3) with a mean time in function of 8.0 years (SD 1.9). Fifty-six patients (47.9%) were non-smokers, 42 (35.9%) were former-smokers, and 19 (16.2%) were current-smokers. Thirty-nine subjects (33.4%) were H, whereas 41 (35%) and 37 (31.6%) exhibited PM and PI, respectively. At implant level, the corresponding values were 142 (31.6%), 230 (51.1%) and 78 (17.3%). In the multinomial regression model, significant associations for peri-implant diseases were observed for the mean number of implants per patient (p = .016), function time (p = .048), implants placed simultaneously with guided bone regeneration (p = .016), implant surface (p = .020), keratinized mucosa at the buccal aspect (p = .032), and access to interproximal hygiene (p < .001). In addition, ever smokers >23 pack-years exhibited a significantly higher risk for peri-implantitis (p = .002). Finally, the multinomial regression analysis revealed that subjects who had stopped smoking more than 21 years before the last examination presented a significantly lower risk of peri-implant diseases than a smoking cessation of ≤21 years (p = .028). CONCLUSIONS: Smoke intensity was associated with an increased risk of the development of peri-implantitis. Moreover, the risk of peri-implant diseases might be similar in those subjects who had stopped smoking for more than 21 years with respect to never-smokers.

Systematic review evaluating the influence of the prosthetic material and prosthetic design on the clinical outcomes of implant-supported multi-unit fixed dental prosthesis in the posterior area.

OBJECTIVE: The objectives of the study were to assess the survival, failure, and technical complication rates of implant-supported fixed dental prosthesis (iFDPs) with pontic or splinted crown (iSp C) designs in the posterior area and compare the influence of prosthetic materials and prosthetic design on the outcomes. METHODS: Electronic and manual searches were performed to identify randomized-, prospective-, and retrospective clinical trials with follow-up time of ≥12 months, evaluating the clinical outcomes of posterior iFDPs with pontic or iSp Cs. Survival and complication rates were analyzed using robust Poisson's regression models. RESULTS: Thirty-two studies reporting on 42 study arms were included in the present systematic review. The meta-analysis of the included studies indicated estimated 3-year survival rates of 98.3% (95%CI: 95.6-99.3%) for porcelain-fused-to-metal (PFM) iFDPs, 97.5% (95%CI: 95.5-98.7%) for veneered zirconia (Zr) iFDPs with pontic, 98.9% (95%CI: 96.8-99.6%) for monolithic or micro-veneered zirconia iFDPs with pontic, and 97.0% (95%CI: 84.8-99.9%) for lithium disilicate iFDPs with pontics. The survival rates for different material combination showed no statistically significant differences. Veneered restorations, overall, showed significantly (p < .01) higher ceramic fracture and chipping rates compared with monolithic restorations. Furthermore, there was no significant difference in survival rates (98.3% [95%CI: 95.6-99.3%] vs. 99.1% [95%CI: 97.6-99.7%]) and overall complication rates between PFM iFDPs with pontic and PFM iSp Cs. CONCLUSIONS: Based on the data identified by this systematic review, PFM, veneered Zr, and monolithic Zr iFDPs with pontic and iSp Cs showed similarly high short-term survival rates in the posterior area. Veneered restorations exhibit ceramic chipping more often than monolithic restorations, with the highest fracture rate reported for veneered Zr iFDPs.

Effect of a novel interocclusal recording method on occlusal accuracy of implant-supported fixed prostheses: A randomized clinical trial.

OBJECTIVES: To investigate the effect of a novel interocclusal recording method on the occlusal accuracy of implant-supported fixed prostheses for partially dentate patients with distal extension. MATERIALS AND METHODS: Twenty patients with two or more adjacent teeth missing in the distal extension and scheduled to receive implant-supported fixed prostheses were enrolled. Two interocclusal recording methods were used: placing polyvinyl siloxane (PVS) on the interocclusal recording caps (test), and placing PVS on healing abutments (control). The intraoral occlusal contacts in maximal intercuspal position (MIP) were compared with those in the mounted casts to calculate sensitivity and positive predictive value (PPV). Then, patients were randomly allocated into two groups to determine which interocclusal record would be used. The implant prostheses' evaluations mainly included occlusal adjustment height, volume, and time, occlusal contact score based on articulating paper examination. Paired-samples t-test, Mann-Whitney U test, and least squares regression analyzed the statistic differences. RESULTS: The test method had higher sensitivity to detect intraoral occlusal contacts than the control method (p = .002), but similar PPV (p = .10). During the prostheses' evaluations, the occlusal adjustment height in the test group was significantly lower than that in the control group [99.4 (53.2, 134.2) vs. 159.0 (82.3, 247.8) µm, p = .03], while the occlusal contact score before adjustment was higher (p = .006). The groups had similar occlusal adjustment volume and time. CONCLUSIONS: The novel interocclusal recording method for implant-supported fixed prostheses was more accurate and could reduce the occlusal adjustment.

In Silico Mechanical Effort Analysis of the All-On-4 Design Performed With Platform-Switching Distal Short Dental Implants.

Short dental implants with platform matching connection have been used for the rehabilitation of atrophic jaws whenever standard-length dental implants cannot be placed without prior bone augmentation. Yet, there remains a lack of data regarding the risk of technical failures when the all-on-4 configuration is performed in atrophic jaws with platform-switching distal short dental implants. Thus, the current study used the finite element method to evaluate the mechanical behavior at the level of the prosthetic components of the all-on-4 concept performed in atrophic mandible using short-length distal implants with platform switching (PSW) connection. Three models of the all-on-4 configuration were generated in human atrophic mandibles. The geometric models consisted of PSW connection tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) and straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants. A resultant force of 300 N was performed obliquely in the left side and posterior region of the prosthetic bar. The von Mises equivalent stress (σvm) and maximum and minimum principal stresses (σmax and σmin) were performed at level of the prosthetic components/implants and peri-implant bone crest, respectively. The general displacement of the models was also evaluated. The stress analysis was performed on the side of load application. The AO4S configuration showed the lowest values of σvm in the mesial left (ML) and distal left (DL) abutments (37.53 MPa and 232.77 MPa, respectively) and dental implants (91.53 MPa and 231.21 MPa, respectively). The AO4Sh configuration showed the highest values of σvm in the bar screw (102.36 MPa), abutment (117.56 MPa), and dental implant (293.73 MPa) of the ML area. Among the models, the highest values of σmax and σmin were noticed in the peri-implant bone crest of the AO4T design (131.48 MPa and 195.31 MPa, respectively). All models showed similar values of general displacements, which were concentrated in the mandible symphysis. The all-on-4 configurations designed with PSW connection and tilted standard (AO4T; θ = 30 deg; 11 mm-length), straight standard (AO4S; θ = 0 deg; 11 mm-length) or straight short (AO4Sh; θ = 0 deg; 8 mm-length) distal implants were not associated with higher odds of technical failures. The AO4Sh design may be a promising option for the prosthetic rehabilitation of atrophic jaws.

Evaluation of two treatment concepts of four implants supporting fixed prosthesis in an atrophic maxilla: finite element analysis.

BACKGROUND: Currently, oblique placement of long implants or the use of short implants to circumvent the maxillary sinus area and provide support for fixed prostheses are viable alternatives. The purpose of this study was to compare these two treatment concepts and ascertain which one exhibits superior biomechanical characteristics. METHODS: Two different treatment concept models were constructed. The first one, LT4I, consisting of two mesial vertical implants positioned in lateral incisor regions and two distal tilted implants (45°) situated in second premolar regions of the maxilla. The second model, VS4I, includes two mesial vertical implants in lateral incisor regions and two vertically positioned short implants in second premolar regions. Numerical simulations were conducted under three loading types: firstly, oblique forces upon the molars; secondly, vertical forces upon the molars; thirdly, oblique forces upon the incisors. The maximum principal stress (σmax) and minimum principal stress (σmin) of the bone, as well as von Mises stress of the implants, were calcuated. RESULTS: Under oblique loading on the molar, higher stress values in the bone were observed in LT4I group. Under vertical loading on molar, higher stress values in the bone were also observed in LT4I group. Furthermore, little difference was found between the two groups under oblique loading on the incisor. CONCLUSION: Both treatment concepts can be applicable for edentulous individuals with moderate atrophic maxilla. Compared to tilted implants, short implants can transmit less occlusal force to the supporting tissues.

Could various angulated implant depths affect the positional accuracy of digital impressions? An in vitro study.

PURPOSE: The purpose of this in vitro investigation was to assess how implant depth could affect the three-dimensional positional accuracy of digital impressions made from angulated implants. MATERIALS AND METHODS: Four modified maxillary models were printed and divided into four study groups. In each model, two angulated implant analogs were placed at the sites of the first premolar and first molar at four different depths of 1 (G1), 2 (G2), 3 (G3), and 4 (G4) mm from the models' edentate area. Scan bodies were connected to the analogs, and one operator made 10 full-arch scans for each master model using an intraoral scanner. Afterward, the marginal gingival part of all models was removed, and digital scans were performed for each model using a laboratory scanner to achieve a reference STL file as the control group. One-way ANOVA and Leven's tests were used to measure and compare the 3D distance deviations across research groups after the superimposing test and control scans. RESULTS: A significant difference between research groups was revealed by trueness and precision analysis (p < 0.001). The trueness and precision results obtained for G1 and G4 were significantly better than those for G2 and G3 (p < 0.05). CONCLUSION: This study demonstrated that implant depth could affect the digital implant impressions' 3D positional accuracy.

A Stereophotogrammetry Face Study Between Dentate and Edentulous Adults Rehabilitated with Either a Conventional Complete or an Implant-Supported Fixed Complete Denture.

Quantifying in edentulous patients the facial collapse and whether complete conventional denture (CCD) and implant-supported fixed complete denture (ISFCD) can restore the facial proportions to match those of a dentate patient (CG) is relevant for clinical dentists. One hundred and four participants were enrolled and divided into edentulous (n=56) and CG (n=48). The edentulous participants were rehabilitated with CCD (n=28) or ISFCD (n=28) in both arches. Anthropometric landmarks in the face were marked and captured by stereophotogrammetry. Linear, angular, and surface measurements were analyzed and compared among groups. The statistical analysis was performed by an independent t-test, the one-way ANOVA, and Tukey's test. The significance level was set at 0.05. The facial collapse was quantified as a significant shortening of the lower third of the face affecting facial aesthetics in all parameters evaluated and the same was observed in comparison among CCD, ISFCD, and CG. The CCD presented statistical differences with the CG group in the lower third of the face and labial surface, and the ISFCD showed no statistical differences with the CG and CCD. The facial collapse in edentulous patients could be restored through oral rehabilitation with an ISFCD similar to those of dentate patients.

Oral function of implant-assisted removable partial dentures with magnetic attachments using short implants: A prospective study.

OBJECTIVES: This prospective study aimed to compare the oral functions of removable partial dentures (RPDs) with those of implant-assisted removable partial dentures (IARPDs) with short implants and magnetic attachments in patients with mandibular Kennedy class I and II. MATERIAL AND METHODS: Thirty participants with mandibular Kennedy class I or II and at least three distal missing teeth were recruited. Oral functions, including mixing ability, comminuting ability, maximum bite force, and occlusal contact area, were assessed for RPDs (stage 0), IARPDs with healing caps (stage 1), and IARPDs with magnetic attachments (stage 2). The implants were loaded with occlusal force in stages 1 and 2. Finally, the data of the 27 participants who completed the evaluation at stage 2 were analyzed. The Wilcoxon signed-rank test with Bonferroni correction was used to assess the differences in the oral functions among the different stages. RESULTS: The implant survival rate was 93.8%. There were significant differences in the comminuting ability and occlusal contact area between stages 0 and 2 (p < .001 and p = .036, respectively) and stages 1 and 2 (p = .003 and p = .015, respectively). Regarding the maximum bite force, there was a significant difference between stages 1 and 2 (p = .018). However, there was no significant difference in the mixing ability between the three stages. CONCLUSIONS: Within the limitations of this study, it was concluded that IARPDs in the mandible with short implants and magnetic attachments may improve oral functions.

Clinical outcomes of all-ceramic single crowns and fixed dental prostheses supported by ceramic implants: A systematic review and meta-analyses.

OBJECTIVE: To analyze the clinical outcomes of all-ceramic single crowns (SCs) and fixed dental prostheses (FDPs) supported by ceramic implants. MATERIALS AND METHODS: Based on a focused question and customized PICO framework, electronic (Medline/EMBASE/Cochrane) and manual searches for studies reporting the clinical outcomes of all-ceramic SCs and FDPs supported by ceramic implants ≥12 months were performed. The primary outcomes were reconstruction survival and the chipping proportion. The secondary outcomes were implant survival, technical complications, and patient-related outcome measurements. Meta-analyses were performed after 1, 2, and 5 years using random-effect meta-analyses. RESULTS: Eight of the 1,403 initially screened titles and 55 full texts were included. Five reported on monolithic lithium disilicate (LS2) SCs, one on veneered zirconia SCs, and two on veneered zirconia SCs and FDPs, which reported all on cement-retained reconstructions (mean observation: 12.0-61.0 months). Meta-analyses estimated a 5-year survival rate of 94% (95% confidence interval [CI]: 82%-100%) for overall implant survival. Reconstruction survival proportions after 5 years were: monolithic LS2, 100% (95%CI: 95%-100%); veneered zirconia SCs, 89% (95%CI: 62%-100%); and veneered zirconia FDPs 94% (95%CI: 81%-100%). The chipping proportion after 5 years was: monolithic LS2, 2% (95%CI: 0%-11%); veneered zirconia SCs, 38% (95%CI: 24%-54%); and veneered zirconia FDPs, 57% (95%CI: 38%-76%). Further outcomes were summarized descriptively. CONCLUSIONS: Due to the limited data available, only tendencies could be identified. All-ceramic reconstructions supported by ceramic implants demonstrated promising survival rates after mid-term observation. However, high chipping proportions of veneered zirconia SCs and, particularly, FDPs diminished the overall outcome. Monolithic LS2 demonstrated fewer clinical complications. Monolithic reconstructions could be a valid treatment option for ceramic implants.

Microleakage assessment of CAD-CAM Cobalt-Chrome and Zirconia abutments on a conical connection dental implant: A comparative in vitro study.

OBJECTIVE: To assess the marginal and bacterial microleakage in zirconia and CAD-CAM or cast Co-Cr implant abutments. METHODS: Sixty-four conical connection implants with their respective abutments were divided into four groups (Co-Cr (milled, laser-sintered, and cast) and Zirconia (milled)). All specimens were subjected to a chewing simulation and thermocycling. After aging process, specimens were submerged in a 0.2% methylene blue solution with Porphyromonas gingivalis (P.g) for 48 h. The marginal microleakage was measured using a 40× optical microscopy at the internal part of the implant, and when positive microleakage was observed, a DNA isolation with a polymerase chain reaction (PCR) test was used. The microbiological assessment was based on colony forming units (CFUs). RESULTS: Thirty (47%) implant-abutments presented microleakage and the PCR was performed on those specimens (1 Zirconia, 1 Co-Cr milled, 14 Co-Cr laser-sintered and 14 cast). Seven specimens (1 Co-Cr laser-sintered and six cast) presented values below the PCR detection limit (< 100 CFUs). The lowest CFUs count occurred in the Co-Cr milled group (5.17E+02 CFUs/ml) followed by zirconia (7.70E+03 CFUs/ml). The Co-Cr cast (9.39E+03 CFUs/ml) and laser-sintered (2.4E+05 CFUs/ml) groups had higher bacterial count. The CFU count comparison performed between Co-Cr cast and laser-sintered resulted in a statistically significant differences in favor of Co-CrCL (p < .05). CONCLUSIONS: The abutment material and fabrication technique affected the implant-abutment microleakage. Although the CAD-CAM abutments presented favorable results, all tested groups presented microleakage.

Failure Load of Monolithic Lithium Disilicate Implant-Supported Single Crowns Bonded to Ti-base Abutments versus to Customized Ceramic Abutments after Fatigue.

PURPOSE: This laboratory study analyzed the influence of retention mode (screw- vs cement retained) and fatigue application on the failure load of monolithic lithium-disilicate (LDS) implant-supported single crowns (ISSC). MATERIAL AND METHODS: A total of 72 samples of monolithic LDS (*Ivoclar Vivadent) ISSC were divided into three groups (n = 24) according to their type of retention mode: Group Ti-CAD: Titanium base (SICvantage CAD/CAM Abutment red (SIC invent AG), screw-retained milled monolithic LDS (IPS e.max CAD*); Group Ti-P: Titanium base (SICvantage CAD/CAM Abutment red), screw-retained pressed monolithic LDS (IPS e.max Press*) and Group Ti-Cust: Titanium base with cemented press LDS (IPS e.max Press*) crown on a LDS (IPS e.max Press*) custom abutment. A mandibular first molar implant-supported single crown model was investigated (Titanium implant: SICvantage-max, SIC invent AG, diameter: 4.2 mm, length: 11.5 mm). Half of each group (n = 12) w​ere exposed to fatigue with cyclic mechanical loading (F = 198 N, 1.2 million cycles) and simultaneous thermocycling (5-55°C). Single load to failure testing was performed, before (Subgroups Ti-CAD, Ti-P, and Ti-Cust) and after (Subgroups Ti-CAD-F, Ti-P-F, and Ti-Cust-F) fatigue. Weibull distribution was used to determine the characteristic strength and Weibull modulus differences between groups. Probability of survival at 900N load was calculated. RESULTS: No samples failed during fatigue. Characteristic strength values were as follow: Ti-CAD: 3259.5N, Ti-CAD-F: 2926N, Ti-P: 2763N, Ti-P-F: 2841N, Ti-Cust: 2789N, Ti-Cust-F: 2194N. Whereas no difference was observed between pressed or milled monolithic crowns cemented to Ti-base, regardless of loading condition, fatigue decreased the characteristic strength of crowns cemented to custom abutments. Probability of survival at 900 N was not significantly different between groups. CONCLUSIONS: Screw-retained pressed or milled monolithic LDS ISSC, cemented directly to Ti-base abutments or LDS crowns cemented to custom ceramic abutments resist physiological chewing forces after simulated 5-year aging in the artificial mouth and presented equally high probability of survival. However, a significant decrease in load to failure was observed in LDS crowns cemented to custom ceramic abutments after fatigue. Prospective clinical trials are needed to confirm the results of this laboratory investigation.

Probing single-tooth dental implants with and without prostheses: a cross-sectional study comparing healthy and peri-implant mucositis sites.

AIM: To evaluate differences in probing depth (PPD) with and without a prosthesis in implants without interproximal bone loss (IBL). Secondarily, to assess whether the difference in PPD measured with and without the crown was affected by diagnosis or implant location. MATERIALS AND METHODS: A cross-sectional study was conducted in patients with a single screw-retained implant-supported crown in the posterior area, without IBL. PPD and was assessed before and after crown removal. A subgroup analysis compared healthy vs. mucositis implants and premolar vs. molar locations. RESULTS: In the 62 implants analysed (23 healthy and 39 with mucositis), the PPD was 1.15 mm (SD = 1.24 mm) deeper without the prosthesis than with it (p < .001). This difference was independent of the implant location (p > .05) except for buccal sites (p = .048). The mean PPD difference for implants with mucositis was 0.95 mm (SD = 1.19 mm; p < .001) while healthy implants had a mean PPD variation of 1.47 mm (SD = 1.29 mm; p < .001). CONCLUSION: The presence of prosthesis in single-tooth implants in the posterior area without IBL seems to lead to an underestimation of PPD that appears to be significant in implants diagnosed with mucositis, although the difference is even greater in healthy implants. Further studies are needed to confirm these findings.

Implant failure and associated risk indicators: A retrospective study.

OBJECTIVES: To evaluate early and late implant loss rates in a sample of patients who had received implant therapy in a university setting as well as patient- and implant-related variables for implant failure. MATERIAL AND METHODS: This is a retrospective analysis in a cohort of patients who were treated with implant-supported restorative therapy during the period 2001-2012. Patients were randomly selected from an electronic database and scheduled for an appointment to record subject and implant characteristics. The primary study outcome was implant loss (i.e., early and late implant failure). RESULTS: A total of 190 patients and 710 implants were included. The mean time in function was 8.2 (SD 2.4) years. Four implants (0.6%) failed in four patients (2.1%) prior to connection of the restoration within a mean period of 1.5 (SD 1.3) months after surgical procedure. Moreover, 17 subjects (8.9%) exhibited late implant failure, representing 26 implants (3.7%), after a mean follow-up of 5 years (SD 2.2) from prosthesis connection. The final multivariable model indicated three factors related to late implant failure: subjects <55 years (OR = 3.62; 95% CI 1.46-10.22; p = .002), smokers/former smokers (OR = 6.25; 95% CI 1.70-17.52; p = .005), and implants with no access to interproximal hygiene (OR = 7.25; 95% CI 2.20-28.25; p < .001). CONCLUSIONS: The rate for early and late implant failure in a sample of 190 patients who had received implant therapy in a university setting was 2.1% and 8.9%, respectively, at subject level. Subjects <55 years and smokers/former smokers as well as implants with inadequate access to interproximal hygiene were significantly associated with late implant failure.

Implant and prosthesis survival rates of full-arch immediate prostheses supported by implants with and without bicortical anchorage: Up to 2 years of follow-up retrospective study.

OBJECTIVES: To compare implant and prosthesis survival rates between full-arch immediate prostheses supported by 4 hydrophilic implants with bicortical anchorage and by 5 or 6 hydrophilic implants placed without bicortical anchorage. MATERIAL AND METHODS: The sample was retrospectively selected and comprised completely edentulous patients treated with full-arch immediate prostheses supported by Morse Taper hydrophilic implants. The selected patients were divided into four groups, according to the region of implant placement and type of anchorage. Differences in implant and prosthesis survival rates between groups, as well as the influence of bicortical anchorage on implant primary stability, were verified using Fisher's exact tests (significant at p < .05). RESULTS: The sample comprised 392 implants, 72 were placed in the maxilla with bicortical anchorage, and 85 were placed without. In the mandible, 140 implants were placed with and 95 were placed without bicortical anchorage. The follow-up period was up to 24 months. A 98.8% implant survival rate was observed for the group of implants placed without bicortical anchorage in the maxilla, and of 100% for the other groups. The overall implant survival rate was 99.7% (391 of 392 implants). Prosthesis survival rate was 100% for all groups. No differences were observed between groups with respect to implant and prosthesis survival rates. Significantly higher primary stability was observed for implants placed with bicortical anchorage in both jaws. CONCLUSION: Predictable results and high survival rates were achieved within the period evaluated by the present retrospective study, with immediate full-arch prostheses when only four hydrophilic implants are placed bicortically.

Osseointegrated implant survival, success and prosthodontic outcomes in composite free flaps: A 10-year retrospective cohort study.

OBJECTIVES: To evaluate implant survival, success and prosthodontic outcomes in a variety of composite free flaps. MATERIAL AND METHODS: A retrospective analysis of patient records was used for data collection of implants placed into flaps. Free flap donor sites included fibula, iliac crest, scapula, medial femoral condyle and radial forearm. Kaplan-Meier survival curves were used to estimate survival. Cox regression was used to assess variables affecting survival, and binary logistic regression was utilised to determine effect of variables on prosthodontic outcomes. RESULTS: There were 150 implants placed into 45 fibula, 98 implants into 29 iliac crest, 62 implants into 22 scapula, 6 implants into 3 medial femoral condyle and 2 implants in radial forearm composite free flaps. There was no difference in survival or success between or within the various flaps. Active smoking, increasing age, male gender and radiotherapy were associated with implant failure. Of patients completing prosthodontic rehabilitation, 93% were successful. There was no difference in likelihood of failure between different flap types. Fixed implant-supported dentures were associated with poor oral hygiene compared with removable designs (OR2.9, 95%CI 1.1-7.8, p = .03). CONCLUSIONS: There is adequate survival and success of implants in common flaps. Caution is required when planning implants in patients exposed to radiotherapy and smokers. Ability to maintain adequate oral hygiene is an important prosthetic design consideration.