Clinical outcomes of full-arch immediate fixed prostheses supported by two axial and two tilted implants: A retrospective cohort study with 12-15 years of follow-up.

PURPOSE: To retrospectively assess clinical and radiographic outcomes of immediately loaded full-arch fixed prostheses supported by axial and tilted implants up to 15 years of function. MATERIALS AND METHODS: Patients with one completely edentulous arch received an immediate full-arch fixed prosthesis supported by two anterior axial and two posterior tilted implants. Definitive prosthesis consisting of a CAD-CAM titanium framework and acrylic teeth was delivered 6 months later. Patients were regularly followed to assess clinical parameters and marginal bone level (MBL) change. Multilevel regression analysis was performed to investigate factors affecting implant failure and MBL. RESULTS: Six hundred ninety-two implants were placed in 72 maxillae and 101 mandibles. Seven maxillary implants (5 axial and 2 tilted) in 6 patients and 12 mandibular implants (6 axial and 6 tilted) in 5 patients failed. 15-year cumulative implant survival was 97.51% and 96.91% in maxilla and mandible, respectively (p = .64). After 10 years, the difference in MBL between axial and tilted implants was not significant in the maxilla (p = .47, 65 patients), while it was in the mandible (p < .001, 80 patients). Significant higher bone loss was reported in the mandible at both 5- and 10-year follow-up (p < .001 and p = .004, respectively). Mixed-effect multilevel linear regression evidenced a correlation between arch and bone loss at 5- and 10-year follow-up, while no correlation was found with age, gender, smoking, diabetes, and history of periodontal disease. CONCLUSION: This long-term study suggests that the present technique can be considered a viable treatment modality for the immediate rehabilitation of both maxilla and mandible.

Copy-paste concept: Full digital approach in the management of gingival emergence profiles.

OBJECTIVE: Obtaining a perfect integration of a prosthetic rehabilitation on natural teeth and implantys in the esthetic zone requires a deep knowledge of the biological processes and a clear understanding of the characteristics of the restorative materials. Once the soft tissue profile has been created with the placement of a temporary prosthesis, the ability to accurately transfer information about the tissue profile and the contour of the restoration for the fabrication of the definitive crowns can be challenging. CLINICAL SIGNIFICANCE: This paper illustrate the copy paste full digital workflow, a simple protocol that allows to create definitive restorations by making an exact copy of the temporary prosthesis that has been placed in function in the patient's mouth.

Insertion and removal torque of dental implants placed using different drilling protocols: An experimental study on artificial bone substitutes.

PURPOSE: The aim of this in vitro study was to measure the insertion and removal torque values of dental implant replicas inserted into artificial bone blocks using different surgical burs and drilling protocols. MATERIALS AND METHODS: Four types of artificial, polyurethane bone blocks were used with different thicknesses (1 and 2 mm) and densities (soft-1 mm, soft-2 mm, dense-1 mm, and dense-2 mm) of the simulated cortical and cancellous bone, respectively. Each bone construct was drilled with Straumann and Densah drills in both clockwise and counterclockwise directions for a total of 16 experimental conditions. For every scenario, 38 implant replicas were inserted and then removed after 1 min. Outcomes of interest were the insertion and removal torque values which were recorded by a torque meter. ANOVA and Tukey HSD tests were used to assess differences across each combination of drill, direction, and bone type. RESULTS: Densah counterclockwise registered statistically greater values for both insertion and removal torque, followed by Densah clockwise, Straumann counterclockwise, and Straumann clockwise. Increasing insertion and removal torque values were progressively reported for bone type (soft-1 mm, dense-1 mm, soft-2 mm, and dense-2 mm). The mean values of insertion and removal torque were significantly different (p < 0.05) across the four bone types, different burs, and with the two drilling modalities. CONCLUSIONS: Densah bur resulted in significantly greater values of torque compared to the Straumann drills for all the experimental conditions. The thickness of the cortical layer and the counterclockwise drilling direction play a significant role in determining the implant insertion torque.

Survival rates, patient satisfaction, and prosthetic complications of implant fixed complete dental prostheses: a 12-month prospective study.

PURPOSE: To determine the survival rate, incidence of prosthetic complications, and patient satisfaction of implant fixed complete dental prostheses (IFCDPs) after a mean observation period of 1.4 years. MATERIALS AND METHODS: Twenty-eight (28) eligible participants were recruited according to specific inclusion and exclusion criteria. The definitive metal-acrylic resin IFCDPs consisted of titanium bars veneered with acrylic resin and acrylic denture teeth. Prosthodontic complications, divided into major and minor, were monitored. Parameters such as gender, jaw location, bruxism, and occlusal scheme were evaluated. Moreover, a questionnaire was administered throughout the study to assess patient satisfaction. Poisson regression as well as repeated measures ANOVA were used for statistical analysis. RESULTS: Fourteen (14) males and 14 females were enrolled and followed-up at 3, 6, and 12 months. All IFCDPs survived (100% survival rate). The most frequent minor complication was the loss of material used to close the screw access hole (20% out of total complications). The most frequent major complication was chipping of the acrylic denture teeth (77.14% out of total complications). Gender (p = 0.008) and bruxism (p = 0.030) were significant predictors for the total major complications (major wear and major chipping) while occlusal scheme was a significant predictor for major chipping events (p = 0.030). CONCLUSIONS: While IFCDPs demonstrated high prosthetic survival rates, they also exhibited a high number of chipping events of the acrylic veneering material, especially in males, bruxers, and individuals with canine guidance occlusion. However, the occurrence of these prosthetic complications did not negatively affect patient satisfaction.

Outcomes of Fixed Full-Arch Rehabilitations Supported by Tilted and Axially Placed Implants: A Systematic Review and Meta-Analysis.

PURPOSE: To evaluate the performance of fixed complete dental prostheses supported by axial and tilted implants after at least 3 years of follow-up. MATERIALS AND METHODS: An electronic search plus a hand search up to April 2021 was undertaken. Clinical studies were selected using specific inclusion criteria, independent of the study design. The main outcomes were cumulative implant survival rate, marginal bone level changes, and complications, after ≥ 3 years of follow-up. The difference in outcomes between axial and tilted implants and between the maxilla and mandible was evaluated using meta-analysis and the Mantel-Cox test. RESULTS: Out of 824 articles retrieved, 24 were included. In total, 2,637 patients were rehabilitated with 2,735 full prostheses (1,464 maxillary, 1,271 mandibular), supported by 5,594 and 5,611 tilted and axial implants, respectively. In a range between 3 and 18 years of follow-up, 274 implants failed. The cumulative implant survival rate was 93.91% and 99.31% for implants and prostheses, respectively. The mean marginal bone level change was moderate, exceeding 2 mm in only two studies. Marginal bone loss was significantly lower around axial compared with tilted implants (P < .0001), whereas it was not affected by arch (maxilla vs mandible; P = .17). CONCLUSION: Fixed complete dental prostheses supported by tilted and axially placed implants represent a predictable option for the rehabilitation of edentulous arches. Further randomized trials are needed to determine the efficacy of this surgical approach and the remodeling pattern of marginal bone in the long term.

Complete Digital Workflow for Prosthesis Prototype Fabrication with the Double Digital Scanning (DDS) Technique: A Prospective Study on 16 Edentulous Maxillae.

PURPOSE: To assess the accuracy of fit of milled prosthesis prototypes for completely edentulous patients using a digital workflow. MATERIALS AND METHODS: Sixteen patients received intraoral full-arch digital scans with the double digital scanning (DDS) technique and the generated standard tessellation language (STL) files were superimposed and imported into computer-aided design software (Exocad DentalCAD, exocad GmbH, Darmstadt, Germany) for design. After the design, each master STL file was used for computer-aided manufacturing of the prosthesis prototypes through a complete digital workflow. The primary outcome was the accuracy of fit assessment of the digitally fabricated prototypes on verified patient master stone casts. Two blinded clinicians tested the accuracy of fit of the milled prosthesis prototypes on the verified master stone casts utilizing the screw-resistance test and direct observation. RESULTS: Out of the 16 digitally fabricated prototypes from intraoral full-arch digital scans, all 16 presented with an accurate fit on verified master stone casts. CONCLUSIONS: Digitally fabricated full-arch prosthesis prototypes can be generated with a complete digital workflow leading to clinically acceptable fit.

Implant survival and biologic complications of implant fixed complete dental prostheses: An up to 5-year retrospective study.

STATEMENT OF PROBLEM: Limited information is available on the association between prosthesis-associated risk factors and biologic complications for patients with implant fixed complete dental prostheses (IFCDPs). PURPOSE: The purpose of this retrospective study was to assess the implant survival and biologic complications of IFCDPs up to 5 years of follow-up. MATERIAL AND METHODS: Patients who had received IFCDPs between August 1, 2009 and August 1, 2014 were identified through an electronic health record review. Those who consented to participate in the study attended a single-visit study appointment. Clinical and radiographic examinations, intraoral photographs, and peri-implant hard and soft tissues parameters were assessed. Only prostheses which could be removed during the study visit were included. Associations between biologic complications and prosthetic factors, such as time with prosthesis in place, prosthesis material, number of implants, cantilever length, and type of prosthesis retention, were assessed. RESULTS: A total of 37 participants (mean ±standard deviation age 62.35 ±10.39 years) with 43 IFCDPs were included. None of the implants had failed, leading to an implant survival of 100% at 5.1 ±2.21 years. Ten of the prostheses were metal-ceramic (Group MC) and 33 were metal-acrylic resin (Group MR). Minor complications were more frequent than major ones. Considering minor complications, peri-implant mucositis was found in 53% of the implant sites, more often in the maxilla (P=.001). The most common major biologic complication was peri-implantitis, which affected 4.0% of the implants, more often in the mandible (P=.025). Peri-implant soft tissue hypertrophy was present 2.79 times more often (95% CI: 1.35 - 5.76, P<.003) around implants supporting metal-acrylic resin prostheses than metal-ceramic ones, with the former type also showing significantly more plaque accumulation (P<.003). CONCLUSIONS: Biologic complications such as soft tissue hypertrophy and plaque accumulation were more often associated with metal-acrylic resin prostheses. Peri-implant mucositis occurred more often under maxillary IFCDPs, while peri-implantitis appeared more common around mandibular implants.

Clinical outcomes and biological and mechanical complications of immediate fixed prostheses supported by zygomatic implants: A retrospective analysis from a prospective clinical study with up to 11 years of follow-up.

BACKGROUND: Zygomatic implants alone or in combination with conventional implants have been used for severe atrophic maxillary arches. Long-term outcomes of extramaxillary technique need validations. PURPOSE: To retrospectively assess the clinical outcomes and the prevalence of surgical, biological, and prosthetic complications of implant-fixed complete dental prostheses (IFCDPs) supported by zygomatic implants up to 11 years of follow-up. MATERIALS AND METHODS: Dental records of 34 subjects treated between October 2008 and June 2019 were reviewed. Patients received an immediate fixed full-arch prosthesis supported solely by zygomatic implants or by a combination of zygomatic and conventional implants. RESULTS: A total of 90 zygomatic implants and 53 standard implants were placed. Up to 11 years of follow-up, two conventional implants were lost, leading to 96.2% success rate for conventional implants and 100% for zygomatic implants. Marginal bone loss for conventional implants averaged 0.85 ± 0.17 mm after the first year and 1.36 ± 0.12 mm after 10 years, resulting in full implant success. No prosthesis was lost. The main surgical complication was the perforations of the Schneiderian membrane, occurring in five patients and in seven sinus cavities. Considering the biological complications, mucositis for standard and zygomatic implants ranged between 21%-35% and 26%-40%, respectively. No peri-implantitis were reported. Soft tissue hypertrophy ranged between 1.8% and 30% for conventional implants and 1.1%-35% for zygomatic implants. Inflammation under the prosthesis ranged between 33% and 50%. For the mechanical complications, abutment loosening was recorded in 5.8% of cases (two patients), tooth debonding and fracture of the prosthesis happened in five subjects (14.7%), and loosening of the prosthetic screws was reported in one patient (2.9%). CONCLUSIONS: Immediate rehabilitation of the severely atrophic maxilla with zygomatic implants alone or in combination with standard implants could be considered a viable treatment modality.

Digital Versus Conventional Full-Arch Implant Impressions: A Prospective Study on 16 Edentulous Maxillae.

PURPOSE: A prospective clinical study to compare for the first time the accuracy of digital and conventional maxillary implant impressions for completely edentulous patients. MATERIALS AND METHODS: Sixteen patients received maxillary implant supported fixed complete dentures. After the verification of the conventional final casts, the casts were scanned with a desktop (extraoral) scanner. Intraoral full-arch digital scans were also obtained with scan bodies and STL files. Extraoral and intraoral scans were superimposed and analyzed with reverse engineering software. The primary outcome measure was the assessment of accuracy between scans of the verified conventional casts and digital full-arch impressions. The secondary outcome was the effect of the implant number on the 3D accuracy of impressions with Spearman's rank correlation coefficient. RESULTS: The 3D deviations between virtual casts from intraoral full-arch digital scans and digitized final stone casts generated from conventional implant impressions were found to be 162 ± 77 µm. In the 4-implant group, 5-implant group, and 6-implant group the 3D deviations were found to be 139 ± 56 µm, 146 ± 90 µm, and 185 ± 81 µm, respectively. There was a positive correlation between increased implant number and 3D-deviations, but there was no statistically significant difference (p = 0.191). CONCLUSIONS: The 3D accuracy of full-arch digital implant scans lies within previously reported clinically acceptable threshold. Full-arch digital scans and a complete digital workflow in the fabrication of maxillary fixed complete dentures may be clinically feasible.

Survival rates and prosthetic complications of implant fixed complete dental prostheses: An up to 5-year retrospective study.

STATEMENT OF PROBLEM: Implant fixed complete dental prostheses (IFCDPs) are widely used in the rehabilitation of completely edentulous patients, yet limited information is available on the relationship between prosthetic complications and patient-associated and prosthesis-associated risk factors. PURPOSE: The purpose of this retrospective study was to assess the prosthetic complication and survival rates of IFCDPs after a mean observational period of 3.5 years. MATERIAL AND METHODS: Eligible participants were identified by an electronic health record review. The study consisted of a review of the dental record and a single-visit study appointment when a comprehensive examination was performed, including a review of the medical and dental history, clinical and radiographic examination, intraoral photographs, patient satisfaction questionnaire, and occlusal analysis. Prosthodontic parameters and risk factors were assessed, including time with the prosthesis in place, bruxism, occlusal device use, prosthesis material, number of implants, cantilever length, and mode of prosthesis retention. Association between these prosthodontic parameters and risk factors and the observed prosthetic complications was assessed. RESULTS: A total of 37 participants (mean age 62.35 ±10.39 years) with 48 IFCDPs were included. Thirty-eight prostheses were metal-acrylic resin (MR group), whereas 10 were metal-ceramic (MC group). Five of the 48 prostheses failed during the follow-up period, a cumulative prosthesis survival rate of 88%. Minor complications were more frequent than major complications. The most frequent minor complication was loss of screw access hole material (5.18%/year), whereas the most frequently observed major complication was major wear of the prosthetic material (5.85%/year). A significant association was found between not wearing an occlusal device and minor chipping, loss of access hole material, and framework fracture. Minor chipping was significantly associated with bruxism, whereas the opposing dentition significantly affected the total number of prosthetic complications. CONCLUSIONS: High survival rates were observed with both MR and MC IFCDPs. No significant difference was found between MR and MC groups in terms of patient satisfaction, as well as total number of prosthetic complications.

Immediate rehabilitation of the posterior maxilla with extensive sinus pneumatization with one axial and one trans-sinus tilted implant: a 3-year clinical report and a classification.

Implant rehabilitation of the posterior maxilla can entail difficulties due to reduced bone quantity and poor bone quality, especially after long-term edentulism. In some patients, multiple surgeries are necessary, which may lead to higher patient morbidity and longer treatment times before a prosthetic rehabilitation can be achieved. This article presents an immediate fixed prosthesis in a posterior atrophic maxilla supported by 1 anterior axial implant and 1 posterior tilted fixture placed with an intrasinus insertion. Additionally, a classification scheme for immediate treatment for the posterior maxilla based on the available residual bone is provided.

Immediate function of partial fixed rehabilitation with axial and tilted implants having intrasinus insertion.

Implant-supported rehabilitation of the posterior maxilla could be challenging because hyperpneumatization of the maxillary sinus might reduce the bone height. In this study, the authors report preliminary results of a new treatment modality for the partial fixed rehabilitation of posterior maxilla with immediate function by using 1 anterior axial implant and 1 posterior tilted implant with intrasinus mesial insertion. From 2009 to 2011, 10 patients (6 women and 4 men) with missing upper premolars and molars were recruited and treated according to this protocol. Each patient received a partial fixed bridge supported by 1 axial anterior implant and 1 posterior implant placed with a 30-degree mesial inclination and intrasinus insertion. Autologous bone was positioned to fill the maxillary sinus cavity and to cover the exposed implant surface after elevation of the anterior sinus membrane. A prosthesis with immediate function was positioned within 3 hours, whereas a CAD/CAM final restoration was delivered 6 months later. Follow-ups at 6 and 12 months, and then annually, were scheduled. At each follow-up, plaque level and bleeding scores were assessed, and radiographic evaluation of marginal bone level change was performed at 1 year. The patients were followed up for a mean of 50 months (range, 42-57 mo). No implants were lost, and all prostheses were stable and functional, reporting 100% of implant and prosthetic success rates. After 1 year, bone loss had a mean (SD) of 1.0 (0.4) and 0.9 (0.5) mm for axial and tilted implants, respectively, with no statistically significant differences between them (P > 0.05). The preliminary results suggest that this approach could allow the rehabilitation of posterior maxilla with immediate function in case of reduced bone volume, representing an alternative technique to bone grafting, short implants, and zygomatic or pterygoid implants.

Clinical investigation on axial versus tilted implants for immediate fixed rehabilitation of edentulous arches: preliminary results of a single cohort study.

PURPOSE: The purpose of this clinical investigation was to evaluate full-arch fixed-dental restorations supported by immediate loaded axial and tilted implants in a single-cohort study. Survival rate of axial and tilted implants was compared. MATERIALS AND METHODS: From 2006 to 2010, 30 patients were recruited and treated with dental implants. Provisional fixed-dental prostheses were screw-retained over axial or axial and tilted implants within 24 hours after surgery. Follow-ups at 6, 12, and 24 months and annually up to 5 years were scheduled, and radiographic evaluation of peri-implant bone level changes was conducted. RESULTS: Thirty patients (20 females and 10 males) were followed up for an average of 44 months (range 18-67 months). Six patients received both upper and lower implant rehabilitations, resulting in 36 restorations. A total of two hundred two implants were placed (maxilla = 118; mandible = 84) and 46% of the fixtures were evaluated at the 4-year recall. Four axial implants were lost in three patients, leading to 98.02% implant (97.56% axial implants and 100% tilted implants) and 100% prosthetic cumulative survival rate, respectively. No significant difference in marginal bone loss was found between tilted and axial implants in both jaws at 1-year evaluation. CONCLUSIONS: Midterm results confirmed that immediate loading of axial and tilted implants provides a viable treatment modality for the rehabilitation of edentulous arches.

Immediate fixed rehabilitation of the edentulous maxilla: a prospective clinical and radiological study after 3 years of loading.

PURPOSE: The aim of this study was to prospectively evaluate the clinical and radiographic outcomes of immediate full-arch fixed maxillary prosthesis supported by two axial and four tilted implants after 3 years of loading. MATERIALS AND METHODS: Thirty-two patients with atrophic maxilla were consecutively enrolled and treated. Each patient received a fixed full-arch maxillary rehabilitation supported by four tilted implants that engaged the posterior and the anterior sinus walls and two axial anterior implants. A total of 192 implants (30 Brånemark System MK IV and 162 NobelSpeedy Groovy, Nobel Biocare AB, Göteborg, Sweden) were inserted and immediately loaded. The definitive restorations were placed 6 months later, and follow-up visits were scheduled every 6 months. During follow-ups, marginal bone loss (MBL), plaque and bleeding scores, and patient's satisfaction were recorded. RESULTS: All patients reached at least 3-year follow-up examination (range 36-78, average 55.53 months). Two tilted implants failed before delivering the definitive restoration, resulting in a cumulative survival rate of 98.96%. All final prostheses were stable and functional, resulting in a cumulative survival and success rate of 100%. At the 3-year follow-up there was no significant difference in MBL between axial (1.55 ± 0.31 mm) and tilted implants (1.46 ± 0.19 mm) (p = .05). Plaque and bleeding scores decreased over time, while patient's satisfaction in both aesthetics and function increased. CONCLUSIONS: Implants placement with this configuration could be considered a predictable and cost- and time-effective alternative approach for the immediate restoration of the edentulous maxilla, avoiding bone grafting procedures, even with a medium-term follow-up.

Marginal accuracy of three implant-ceramic abutment configurations.

PURPOSE: Microgaps at the implant-abutment interface allow for microbial colonization, which can lead to peri-implant tissue inflammation. This study sought to determine the marginal accuracy of three different implant-zirconium oxide (zirconia) abutment configurations and one implant?titanium abutment configuration. MATERIALS AND METHODS: Three combinations of implants with custom-made zirconia abutments were analyzed (n = 5/group): NobelProcera abutments/titanium inserts on Replace Select Tapered TiUnite implants (Nobel Biocare) (NP); Encode abutments/NanoTite Tapered Certain implants (Biomet 3i) (B3i); Astra Tech Dental Atlantis abutments/Biomet 3i NanoTite Tapered Certain implants (At). Five custom-made Encode titanium abutments/NanoTite Tapered Certain implants (Ti) were used as a control group. All abutments were fabricated with computer-aided design/computer-assisted manufacture. One-hundred twenty vertical gap measurements were made per sample using scanning electron microscopy (15 scans x 4 aspects of each specimen [buccal, mesial, palatal, distal] x 2 measurements). Analysis of variance was used to compare the marginal fit values among the four groups, the specimens within each group, and the four aspects of each specimen. RESULTS: Mean (± standard deviation) gap values were 8.4 ± 5.6 Μm (NP), 5.7 ± 1.9 Μm (B3i), 11.8 ± 2.6 Μm (At), and 1.6 ± 0.5 Μm (Ti). A significant difference was found between B3i and At. No difference resulted between NP with the other two groups. Gap values were significantly smaller for Ti relative to all zirconia systems. For each ceramic abutment configuration, the fit was significantly different among the five specimens. For 12 of the 15 ceramic abutment specimens, gap values sorted by aspect were significantly different. CONCLUSIONS: The implant?titanium abutment connection showed significantly better fit than all implant?zirconia abutment configurations, which demonstrated mean gaps that were approximately three to seven times larger than those in the titanium abutment system.

Tilted implants for the rehabilitation of edentulous jaws: a systematic review.

PURPOSE: The aim of this review was to evaluate the survival rate of upright and tilted implants supporting fixed prosthetic reconstructions for the immediate rehabilitation of partially and fully edentulous jaws, after at least 1 year of function. MATERIALS AND METHODS: An electronic search of databases plus a hand search on the most relevant journals up to December 2009 was performed. The articles were selected using specific inclusion criteria, independent of the study design. RESULTS: The literature search yielded 347 articles. A first screening based on the title and abstract identified 25 eligible studies. After full-text review of these studies, 10 articles were selected for analysis. Seven were prospective single-cohort studies and three had a retrospective design. A total of 462 patients have been rehabilitated with 470 immediately loaded prostheses (257 in the maxilla, 213 in the mandible), supported by a total of 1,992 implants (1,026 upright and 966 tilted). Twenty-five implants (1.25%) failed in 20 patients within the first year. All failures except one occurred in the maxilla. No significant difference in failure rate was found between tilted and upright implants, nor between maxillary and mandibular implants. No prosthesis failure was reported. Limited peri-implant bone loss was reported with no difference between upright and tilted implants. Full patients' satisfaction for function, phonetics, and esthetics was reported in three studies, based on questionnaires. CONCLUSIONS: The use of tilted implants to support immediately loaded fixed prostheses for the rehabilitation of edentulous jaws can be considered a predictable technique, with an excellent prognosis in the short-medium term. However, randomized long-term trials are needed to determine the efficacy of this surgical approach.

Bone level changes around axial and tilted implants in full-arch fixed immediate restorations. Interim results of a prospective study.

PURPOSE: The aim of this prospective study was to assess clinical outcomes and peri-implant bone level changes around tilted and axial implants supporting full-arch fixed immediate rehabilitations up to 60 months of loading. MATERIAL AND METHODS: Forty-seven patients (22 women and 25 men) were included in the study. Each patient received a full-arch fixed bridge supported by two axial and two distal tilted implants. Loading was applied within 48 hours of surgery. Patients were scheduled for follow-up at 6, 12, 18, 24 months, and annually up to 5 years. At each follow-up, plaque level and bleeding scores were assessed and radiographic evaluation of marginal bone level change was performed. Periapical radiographs were taken using a paralleling technique, and subsequently scanned at 600 dpi. An image analysis software was used to assess bone level. RESULTS: A total of 33 mandibles and 16 maxillae were rehabilitated (two patients received a fixed prosthesis in both arches). One hundred ninety-six Nobel Biocare implants of 4 mm diameter were placed. The mean follow-up duration was 52.8 months (range 30-66 months) in the mandible, and 33.8 months (range 22-40 months) in the maxilla. All subjects attended the scheduled follow-up visits. No implant was lost. No significant difference in marginal bone loss was found between axial and tilted implants in both jaws, at each follow-up. No significant difference in bone loss was found between mandible and maxilla, for both axial and tilted implants at each comparable time frame, although slightly higher mean values were always found for the mandible. CONCLUSION: The use of tilted implants in the immediate rehabilitation of fully edentulous jaws is safe and is not associated to a higher marginal bone loss as compared to axially placed implants.

Immediate rehabilitation of the extremely atrophic mandible with fixed full-prosthesis supported by four implants.

PURPOSE: To prospectively assess the outcome of immediate rehabilitation of extremely atrophic mandibles by a full-arch fixed bridge anchored to four implants. MATERIAL AND METHODS: Twenty patients with edentulous mandibles were included in the study. Each patient received a full-arch fixed bridge supported by two axial and two distal tilted implants. Prosthetic loading was applied within 48 hours of surgery. Patients were scheduled for follow-up every 6 months up to 2 years and annually until 5 years. Radiographic evaluation of marginal bone level change was performed at 1 year. RESULTS: All patients were followed for a minimum of 1 year (range 20-48 months, mean 30.1 months). No failures were recorded to date. The 1-year implant survival rate and prosthesis success rate were 100%. Marginal bone loss around axial and tilted implants was similar at 12-month evaluation, being, respectively, 0.6 ± 0.3 (standard deviation) mm and 0.7 ± 0.4 mm. High patient's level of satisfaction was recorded for function, phonetics, and aesthetics. CONCLUSION: This technique could be considered a viable treatment option for the rehabilitation of the atrophic mandible.

Immediate rehabilitation of the edentulous maxilla: preliminary results of a single-cohort prospective study.

PURPOSE: This article reports preliminary results of a single-cohort prospective study that sought to evaluate a new surgical protocol for the immediate rehabilitation of edentulous maxilla without using bone grafting. MATERIALS AND METHODS: Twenty consecutive patients in need of a full-arch maxillary rehabilitation were included in the study. Each patient received four tilted implants that engaged the posterior and the anterior sinus wall and two axial implants in the anterior maxilla. A total of 120 implants (30 Branemark System MK IV and 90 NobelSpeedy Groovy) was inserted. Acrylic resin provisional prostheses were delivered within 4 hours of implant placement, and definitive restorations were placed 4 to 6 months later. Follow-up visits were scheduled every 6 months for the first 2 years and yearly thereafter. At each follow-up appointment, plaque and bleeding indexes were scored, periapical radiographs were obtained to assess marginal bone level changes, and patient satisfaction was recorded by means of a questionnaire. RESULTS: The follow-up ranged between 18 and 42 months (average, 27.2 months). No implants failed. All prostheses were stable and functional. No adverse events occurred. At 1 year, mean marginal bone loss around axial and tilted implants was similar: 0.8 mm for axial implants (SD 0.4, n = 30) and 0.9 mm for tilted implants (SD 0.5 mm, n = 60) (P > .05). Plaque and bleeding scores decreased over time, and patient satisfaction with both esthetics and function increased. CONCLUSIONS: This technique can be considered a viable treatment modality for the immediate rehabilitation of the edentulous maxilla, as it provides optimal support in the posterior region, minimizes distal cantilevers, and avoids bone grafting or sinus augmentation.

Comparison of tilted versus nontilted implant-supported prosthetic designs for the restoration of the edentuous mandible: a biomechanical study.

PURPOSE: The purpose of the study was to evaluate, using finite element analysis, the stress patterns induced in cortical bone by three distinct implant-supported prosthetic designs. MATERIALS AND METHODS: The first two models consisted of a prosthesis supported by four implants, the distal two of which were tilted, with different cantilever lengths (5 mm and 15 mm). The third design consisted of a prosthesis supported by five conventionally placed implants and a 15-mm cantilever. RESULTS: In the tilted model with 5-mm cantilever and in the nontilted model, the maximum value of compressive stress (-18 MPa) was found near the cervical area of the distal implant. Higher values for compressive stress were predicted near the cervical area of the distal implant in the tilted model with a 15-mm cantilever, as compared to the tilted model with the 5-mm cantilever. For the tilted model with the 5-mm cantilever, peak values of tensile stress were predicted near the cervical area of both the distal (1.25 MPa) and the mesial implants (2.5 MPa). For the nontilted model, the peak value was found near the cervical area of the in-between implant (5 MPa). For the tilted model with 15-mm cantilever, tensile stress values were higher than in the tilted model with 5-mm cantilever. CONCLUSIONS: No significant difference in stress patterns between the tilted 5-mm and the nontilted 15-mm configuration was predicted. The tilted configuration with a 15-mm cantilever was found to induce higher stress values than the tilted configuration with a 5-mm cantilever.