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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.

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Computer-assisted implant planning has become a key diagnostic and therapeutic tool in modern dentistry. This case report emphasizes the possibilities in modern implantology combining virtual implant planning, guided surgery with surgical templates, and immediate function. A 75-year-old female presented with maxillary and mandibular dentures and wanted fixed replacement in minimal appointments. Diagnosis, decision-making, and treatment approaches were based on clinical findings and detailed virtual three-dimensional implant planning. Guided implant placement of six implants in each arch using Tall and Tilted Pin Hole Immediate Loading Technique (TTPHIL ALL TILT®), and immediate loading with a provisional fixed dental prosthesis (FDP) was performed fulfilling patient's functional and esthetic demands in a minimally invasive manner. The final computer-assisted design/computer-assisted manufacturing (CAD/CAM) FDP with a titanium framework and ceramic layering was delivered after six months. At the three-year recall, the implant-supported FDP was free of any complications. Uneventful osseointegration of the dental implants and a healthy peri-implant mucosa were observed. Computer-assisted TTPHIL ALL TILT® technique including three-dimensional virtual implant planning, guided surgery, and CAD/CAM fabrication of provisional and final reconstructions allowed for a concise treatment workflow with favorable esthetic and functional outcomes in this maxillary and mandibular full-mouth case without the need of multiple surgeries in a short treatment time.

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BACKGROUND: Treatment of the edentulous maxilla with a fixed full-arch prosthesis on four immediately loaded implants has been discussed as a treatment option, although generally five implants are recommended for that indication. The precise transfer of the virtually planned position by 3D-guided implant placement is an essential prerequisite for delivering the prefabricated temporary restoration at the time of surgery. Three-point support on the teeth or implants ensures that the template for the guided surgery is soundly seated during the operation. CASE PRESENTATION: In the described case, the three-point support was carried out by teeth and temporary implants in the molar region inserted prior to the CBCT. The virtual implant planning determined the best prosthetic implant position while using the available bone to avoid extensive augmentation. Following this, a metal-reinforced provisional restoration was prepared using a drilling template. Four implants were placed in the planned position with the aid of a tooth-/implant-supported guide. The prosthetic axis of the angulated distal implants is balanced by 17-degree angled abutments. After transferring the implant position to the dental laboratory, the prepared restoration was finalized. The remaining teeth were extracted and the temporary restoration was delivered 3 h after implant placement. The definitive fixed full-arch zirconia restoration with micro layering was placed 9 months later in a stable situation. CONCLUSION: The remarkable accuracy of the implant placement with a surgical template generated from preoperative virtual implant planning ensures a relatively short treatment time and an uneventful and fast recovery with minimal discomfort. The immediate prosthodontic rehabilitation is a benefit, not only for the patient but also for the dental team. Micro-layered monolithic zirconia seems to be a promising option for screw-retained full-arch prostheses.

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BACKGROUND: There is a need for a long-term evidence of implants placed in challenging conditions. The aim of this study was to investigate the outcome of full-arch rehabilitations with the All-on-4 concept for implants inserted with dehiscence or fenestrations. METHODS: This retrospective cohort study included 123 patients (dehiscence, n = 87 patients; fenestrations, n = 28 patients; both conditions, n = 8 patients), with a total of 192 implants in immediate function presenting dehiscence (n = 150), fenestrations (n = 40), or both conditions (n = 2). Primary outcome measures were cumulative implant survival (CSurR) and success (CSucR) rates. Secondary outcome measures were prosthetic survival, marginal bone loss, and incidence of biological complications. RESULTS: CSurRs were 94.1% (overall), 95.6% (dehiscence), and 88.1% (fenestrations) at 10 years using the patient as the unit of analysis. Smoking affected implant failure significantly (p = 0.019). Implant-level CSurRs and CSucRs at 10 years were 96.2% and 93.5% (overall), 97.2% and 94.6% (dehiscence), and 90.0% and 87.6% (fenestrations), respectively. Average bone resorption at 5 and 10 years was 1.22 mm and 1.53 mm, respectively. Biological complications occurred in 18 patients (n = 18 implants). CONCLUSIONS: Implants inserted with dehiscence or fenestrations demonstrate good long-term outcomes with overall high success and survival rates and low average marginal bone resorption, despite an inferior outcome in implants with fenestrations and smoking's negative effect.

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Background: There is a need for long-term evidence of immediate function dental implants inserted in grafted bone. The aim of this retrospective study was to investigate the outcome of full-arch rehabilitations supported by implants in grafted bone. Methods: Thirty-six patients (women: 24; men: 12; average age: 53.5 years) were included (225 implants). Primary outcome measure: to assess implant cumulative success rates evaluated through life tables. Secondary outcome measures: to evaluate implant and prosthetic survival, marginal bone loss, and the incidence of both biological and mechanical complications. Results: Twenty-five implants were unsuccessful giving a dental implant CS rate of 88.1% at 14 years and a 76.8% survival estimation (Kaplan−Meier) using the patient as the unit of analysis. No prosthesis was lost. Average MBL at 10 years was 2.01 mm. The incidence of biological complications was 36%, with smoking affecting it significantly (p < 0.001). The incidence of mechanical complications was 86.1% (45.2% and 54.8% in provisional and definitive prosthesis, respectively. Conclusions: The rehabilitation of atrophic maxillae through dental implants in immediate function inserted in grafted bone is a valid treatment alternative, despite the relevant rate of implant failures and incidence of complications.

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Over the past 17 years, the All-on-4 treatment concept has been a reliable and predictable modality to rehabilitate edentulous jaws with immediate function as full-arch prostheses. This article highlights clinically relevant data compiled by numerous All-on-4 investigators including complications and their remedies, occlusion and cantilever trends, implant size utilization, and controversial topics. We provide insights for navigating the complexities of medically diverse populations, faced by our daily practice, with a focus on patient avoidance, risk factors for implant and prosthetic failures, in hopes to minimize complications so clinicians would choose this treatment with confidence.

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BACKGROUND: Immediate function has become an accepted treatment modality for fixed restorations in completely edentulous jaws. It is known that implant microtopography (surface) may enhance osseointegration, while implant macrotopography (macrodesign) plays an important role in primary stability in the patient requiring an immediate loading. The aim of this retrospective study was to evaluate the clinical and radiographic outcomes of the edentulous subjects treated with narrow and/or regular diameter, which placed and loaded immediately. METHODS: Forty-two consecutive patients received 171 implants, including regular and narrow diameter implants (NDIs). Each jaw, 19 mandibles and 24 maxillae, was treated with a fixed-full arch prosthesis according to the Straumann® Pro Arch concept. The majority (95%) of the restorations were supported by four implants, of which the posterior two implants were tilted. A provisional functional acrylic prosthesis was delivered on the day of surgery. All patients were followed up to 55 months. Cumulative survival rate was determined using Kaplan-Meier analysis. Radiological measurement of marginal bone level was performed. RESULTS: The overall follow-up time for survival rate was up to 55 months. Four implants (3 implants in maxilla, 1 implant in mandible) were lost, resulting in an overall cumulative implant survival rate of 97.7%. Implant survival rate in the axial and tilted implants was not statistically significant. The mean of interproximal marginal bone loss was 0.15 mm after 24 months. Good soft tissue health was observed in almost 99% of patients. The final prosthesis survival rate was 100%. CONCLUSIONS: The results of this retrospective pilot study indicated that total edentulous patients requiring an immediate implant placement and loading can be successfully treated with this implant design. The improved mechanical properties of these implants might give a more conservative treatment option for the jaws showing a severe horizontal alveolar bone resorption.

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BACKGROUND: Immediate provisionalization reduces chair time and improves patient comfort. PURPOSE: To analyze immediate functional loading vs nonfunctional loading with restorations in the posterior mandible for marginal bone defects, implant success/survival, and patient satisfaction. MATERIALS AND METHODS: A randomized controlled clinical trial was designed to assess these parameters based on 20 adult patients who underwent implant surgery, followed by immediate delivery of screw-retained or cemented single or splinted restorations in full occlusal contact or in infraocclusion (test and control group). A questionnaire with visual analog scales was used to assess patient satisfaction. RESULTS: Following 36-month data were evaluable for 9 patients (21 implants) in the study group (immediate functional loading) and for 10 patients (31 implants) in the control group (immediate nonfunctional loading). One implant in the control group was lost, hence the overall implant survival and success rate was 98.2%. Marginal bone defects were consistent with previous studies and comparable in both groups. Periotest values did not significantly change from baseline and the 12-month follow-up (Friedmann test). Patient satisfaction was high and did not involve any significant intergroup differences (Mann-Whitney U-test). CONCLUSIONS: Both types of immediate provisional restorations are viable in selected patients. Larger randomized controlled trials are needed to establish immediate functional loading as a standard treatment for partially edentulous jaws.

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BACKGROUND: Full-arch immediate function protocols such as the All-on-4 concept need long-term validation. PURPOSE: To report the 5-13 year outcomes of the All-on-4 treatment concept for the rehabilitation of the edentulous maxilla. MATERIALS AND METHODS: This retrospective case series study involved 1072 patients (4288 maxillary implants) rehabilitated through the All-on-4 treatment concept. Primary outcome measures were cumulative prosthetic and implant success (life table analysis). Secondary outcome measures consisted in marginal bone loss (MBL) at 5 and 10 years, biological and mechanical complications. The estimation of risk indicators was performed through multivariable analysis for the outcome variables implant failure (Cox regression to estimate hazard ratios and 95% confidence intervals [95% CI]), MBL > 2.8 mm at 5 years, MBL > 3.0 mm at 10 years, biological and mechanical complications (binary logistic regression to estimate odds ratios [OR] with 95% CI). RESULTS: Eighteen patients deceased unrelated to the implant treatment (1.7%) and 219 patients (20.4%) were lost to follow-up. The prosthetic success rate was 99.2%; Implant cumulative survival and success rate was 94.7% and 93.9%, respectively, with up to 13 years of follow-up. Male gender (HR = 1.73), smoking (HR = 1.94), and mechanical complications (HR = 0.59) were significantly associated with implant failure. Average MBL at 5 and 10 years was 1.18 mm (95% CI: 1.16, 1.21) and 1.67 mm (95% CI: 1.58, 1.77) with age (OR = 0.97), male gender (OR = 0.58), smoking (OR = 1.73), and biological complications (OR = 2.1) associated with MBL > 2.8 mm at 5 years. The incidence of biological complications was 7.8% at implant level, with age (OR = 0.98) and smoking (OR = 1.53) significantly associated. The incidence of mechanical complications was 58.8% for the provisional prostheses and 7.3% for the definitive prostheses. CONCLUSIONS: The high success rates registered for both implants and prostheses together with the low MBL confirm the All-on-4 treatment concept is predictable and safe in the long term outcome.

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BACKGROUND: There is a need for studies evaluating the long term outcomes of the All-on-4 treatment concept. PURPOSE: To evaluate the long term clinical and radiographic outcomes of the All-on-4 treatment concept in the mandible. MATERIALS AND METHODS: This retrospective longitudinal case series study included 471 patients (women: 286, men: 185, average age = 57.7 years) rehabilitated with 1884 implants in immediate function supporting 471 fixed full-arch mandibular prostheses and followed for 10 to 18 years. Primary outcome measures were prosthetic survival and implant success and survival (estimated using life tables). Secondary outcome measures were marginal bone loss (MBL) at 10 and 15 years, biological and mechanical complications. Multivariable analysis was used to estimate potential risk indicators for implant failure (Cox regression to estimate hazard ratios and 95% confidence intervals (95%CI)), MBL > 3 mm at 10 and 15 years, biological and mechanical complications (binary logistic regression to estimate odds ratios [ORs] with 95%CI). RESULTS: Twenty-seven patients deceased (5.7%) and 149 patients (31.6%) were lost to follow-up. The cumulative prosthetic survival rate was 98.8%; the implant cumulative survival and success rate was 93% and 91.7%, respectively up to 18 years of follow-up. Previous biological complications (HR = 4.43) were significantly associated with implant failure. Average (95% CI) MBL at 10- and 15-years were 1.72 mm (95%CI: 1.59, 1.85) and 2.32 mm (95% CI: 1.98, 2.66). Smoking (OR = 2.72), previous failure of a contiguous implant (OR = 3.89) and biological complication (OR = 8.11) were associated with MBL > 3 mm. The incidence of biological complications was 11.8% at implant level, with previous failure of a contiguous implant (OR = 5.56), smoking (OR = 1.75), and systemic condition (OR = 1.65) were significantly associated. The incidence of mechanical complications was 36.7% with male gender (OR = 1.67) and type of prosthetic material used in the restoration significantly associated (metal-acrylic OR = 0.30; metal-ceramic OR = 0.22)). CONCLUSIONS: Considering the implant, prosthetic and MBL outcomes it is concluded that the All-on-4 is a viable treatment option validated in the long term. Nevertheless, biological and mechanical complications can occur.

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OBJECTIVES: This multicenter prospective clinical trial investigated immediately provisionalized, anodized, conical connection, tapered implants with platform shifting in maxillary anterior and premolar sites. MATERIALS AND METHODS: Patients requiring single-tooth implant-supported restorations in maxillary anterior and premolar sites were enrolled. Implants were immediately provisionalized and evaluated at insertion, 6 months, and annually thereafter. Outcome measures were marginal bone level change (ΔMBL), cumulative survival rate (CSR), and success rate, soft-tissue parameters, and oral health impact profile (OHIP). ΔMBL and Pink Esthetic Score were analyzed using Wilcoxon signed-rank tests. CSR was calculated using life table analysis. Other soft-tissue parameters were analyzed using sign tests. RESULTS: Of 94 enrolled patients (99 implants), 84 (88 implants) attended the 3-year follow-up. After an initial bone loss between implant insertion and 6 months (- 0.92 ± 1.23 mm), bone levels stabilized from 6 months to 3 years (0.13 ± 0.94 mm) with no significant change. The 3-year CSR was 98.9%, and the cumulative success rate was 96.9%. Papilla index scores of 2 or 3 were observed at 88.6% of sites at the 3-year visit compared with 32.8% at implant insertion. Improvements were observed for all other outcomes, including bleeding on probing, esthetics, plaque, and OHIP. CONCLUSIONS: This restorative protocol was associated with high primary stability, patient satisfaction, stable bone levels, and an overall improvement of the soft tissue outcomes over a 3-year period. CLINICAL RELEVANCE: The presented treatment is a viable option for single-tooth restorations of maxillary anterior teeth and premolars with successful short- to mid-long-term clinical outcomes.

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BACKGROUND: The treatment of patients by the use of immediate implant placement in post-extractive site is a challenging procedure. PURPOSE: A 3-year clinical and radiological study of post-extractive implants placed using flapless guided surgery and immediately functioning. MATERIALS AND METHODS: Thirty-two patients (23 females and 9 males), aged between 44 and 73 years (a mean age of 59.5) were treated with immediate full arch restorations and flapless implant surgery in fresh extraction and healed sites. A double-guide technique stent in conjunction with the NobelGuide system (Nobel Biocare AB, Göteborg, Sweden) was used. RESULTS: A total of 285 implants over 32 patients were assessed. The patients were clinically and radiologically followed for 3 years. One hundred and ninety-five implants were placed in the maxilla and 90 in the mandible. Eight patients received implants in both arches. One hundred and ninety-seven implants were placed in extraction sites (137 maxilla, 60 mandible) and 88 in healed sites (58 maxilla and 30 mandible). The overall cumulative implant survival rate (CISR) was 97.54%. Two implants failed in maxillary healed sites (CISR 96.55%), three in maxillary extraction sites (CISR 97.81%), and two in mandibular extraction sites (CISR 96.66%). No implant failed in healed mandibular sites (CSR 100%). All fixed prostheses maintained stability and good functionality during the follow-up, accounting for a cumulative prosthesis survival rate (CPSR) of 100%. The overall marginal bone level (MBL) was -0.52 mm (SD -0.18) after 6 months, -0.88 mm (SD -0.20) after 12 months, -1.05 mm (SD -0.21) after 24 months, and -1.32 mm (SD -0.41) after 36 months. CONCLUSIONS: Computer-guided surgery using double-template technique (DTT) shows a predictable outcome in the medium term, decreasing treatment timing and patient discomfort.

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BACKGROUND: There is need for more scientific and clinical information on longer-term outcomes of tilted implants compared to implants inserted in an axial position. PURPOSE: Comparison of marginal bone loss and implant success after a 5-year follow-up between axial and tilted implants inserted for full-arch maxillary rehabilitation. MATERIAL AND METHODS: The retrospective clinical study included 891 patients with 3564 maxillary implants rehabilitated according to the All-on-4 treatment concept. The follow-up time was 5 years. Linear mixed-effect models were performed to analyze the influence of implant orientation (axial/tilted) on marginal bone loss and binary logistic regression to assess the effect of patient characteristics on occurrence of marginal bone loss >2.8 mm. Only those patients with measurements of at least one axial and one tilted implant available were analyzed. This resulted in a data set of 2379 implants (1201 axial, 1178 tilted) in 626 patients (=reduced data set). RESULTS: Axial and tilted implants showed comparable mean marginal bone losses of 1.14 ± 0.71 and 1.19 ± 0.82 mm, respectively. Mixed model analysis indicated that marginal bone loss levels at 5 years follow up was not significantly affected by the orientation (axial/tilted) of the implants in the maxillary bone. Smoking and female gender were associated with marginal bone loss >2.8 mm in a logistic regression analysis. Five-year implant success rates were 96%. The occurrence of implant failure showed to be statistically independent from orientation. CONCLUSIONS: Within the limitations of this study and considering a follow-up time of 5 years, it can be concluded that tilted implants behave similarly with regards to marginal bone loss and implant success in comparison to axial implants in full-arch rehabilitation of the maxilla. Longer-term outcomes (10 years +) are needed to verify this result.

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Mechanical complications may have a significant impact on the outcome of implant-supported restorations; however, few studies address the topic. This study investigated the outcomes of implant supported restorations with mechanical complications. A total of 378 patients with 378 restorations supported by 1283 implants were included. Results demonstrated a prosthetic and implant cumulative survival rate at 5 years of 99.7% and 95.7%, respectively. Maxillary implants were a determinant for implant failure (hazard ratio= 6.7), while a reduced risk was registered for single tooth restorations (hazard ratio= 0.1) after adjusting for other variables of interest.

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BACKGROUND: Immediate loading of single implants is generally considered a reliable procedure. PURPOSE: The objective of the present prospective randomized clinical study was to compare the overall treatment outcome following immediate loading (IL) and delayed loading (DL) of single implants after 1 year of follow-up. MATERIALS AND METHODS: Patients with a missing maxillary tooth (15-25) were randomly assigned to IL or DL. The protocol included implant installation in healed sites, immediate loading, delayed loading, temporary screw-retained restoration, and replacement with a permanent single implant crown. Outcome measures were implant survival, marginal bone level, soft tissue changes, papillae index, pink, and white esthetic score (PES and WES), patient judged aesthetics, and oral health impact profile (OHiP-14). RESULTS: Implant survival rate was 100% and 96% for IL and DL, respectively. Implant success rate was 96% and 88% for IL and DL, respectively. Statistically significant lower papilla index scores were found in the IL group at temporary crown and definitive crown placement. An overall statistically significant improvement after 12 months for PES, WES and OHIP-14 was found. CONCLUSION: This prospective randomized study showed that single implants in the maxilla can present satisfactory results with respect to either immediate loading or delayed loading after 12 months.

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BACKGROUND: Implant esthetics may benefit from individualized zirconia abutments copying the emergence profile of the natural tooth and delivered within days after immediate implant insertion. PURPOSE: To investigate the esthetic outcome of the Copy-Abutment technique using the Pink Esthetic Score (PES). MATERIALS AND METHODS: A total of 77 patients with single-tooth implants in the anterior maxilla restored at the day of immediate implant placement using Copy-Abutments and provisional crowns were followed-up after 1 week, 1 month, 4 months, 6 months, 1, 2, 3, 4, and 5 years to assess implant esthetics. RESULTS: PES ranged between 7 and 14 (median: 13) and improved significantly between the 6 month and 1 year follow-up (p < .001), then remained stable up to the fifth year. Significant improvement was seen for the variables PES-6 soft tissue color (p = .002) and PES-7 soft tissue texture (p < .001) up to the 1 year follow-up, while PES-5 alveolar process deficiency deteriorated (p = .016). Mean mucosal recession was 0.26 ± 0.86 mm (range: 0-1.6) after 5 years and not related to gingival biotype. CONCLUSION: Copy-Abutments for immediate restoration of implants in the esthetic zone show satisfactory long-term esthetic outcomes.

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BACKGROUND: There is a necessity of studies documenting the long-term outcome of full-arch flapless rehabilitations. PURPOSE: To evaluate the 7 years implant and prosthesis survival rate and 5-years marginal bone loss of full-arch fixed prosthetic rehabilitations supported by implants in immediate function with the All-on-4® treatment concept using a computer guided surgical protocol (NobelGuide® , Nobel Biocare). MATERIALS AND METHODS: This retrospective clinical study included 111 edentulous patients (n = 53 bruxers; n = 21 smokers; n = 59 systemically compromised), rehabilitated between February 2005 and November 2010 with 532 implants with the All-on-4® treatment concept using NobelGuide® . Outcome measures were implant and prosthesis survival, marginal bone loss at 5-years and the incidence of mechanical and biological complications. Survival was calculated using life-table analysis. Inferential analysis was performed to compare the difference in marginal bone loss between axial and tilted implants. RESULTS: Sixteen patients were lost to follow-up. The implant cumulative survival rate was 94.5% at 7 years. Prosthetic survival was 97.8% (n = 3 prosthetic failures). The average (standard deviation) marginal bone loss at 5 years was 1.3 mm (1.06 mm) overall, 1.27 mm (1.02 mm) for tilted implants and 1.34 mm (1.1 mm) for axial implants (p < .001). Ninety-one patients experienced complications in the provisional prostheses (n = 47 patients who were bruxers; n = 25 patients with implant-supported rehabilitation as opposing dentition) ranging from prosthetic fracture (n = 66 patients) to abutment or prosthetic screw loosening (n = 74 patients). Thirty-three patients experienced complications in the definitive prostheses (all exclusive to patients who were bruxers or had implant-supported rehabilitations as opposing dentition) ranging from acrylic-resin prosthetic/crown fracture (n = 23 patients) to abutment or prosthetic screw loosening (n = 10 patients). Twenty-five patients (22%) registered peri-implant pathology. CONCLUSIONS: Within the limitations of this study, it is possible to conclude that this treatment modality for completely edentulous jaws is possible with high long-term survival outcomes. Bruxing and smoking habits had a negative impact on implant failure, mechanical, and biological complications.

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PURPOSE: To compare the 5-year clinical and radiological outcomes of patients rehabilitated with four or six implants placed using guided surgery and immediate function concept. MATERIALS AND METHODS: Forty patients randomly received four (All-on-4) or six (All-on-6) immediately loaded implants, placed using guided surgery, to support a cross-arch fixed dental prosthesis. Outcome measures were survival rates of implants and prostheses, complications, peri-implant marginal bone loss, and periodontal parameters. RESULTS: No drop-out occurred. Seven implants failed at the 5-year follow-up examination: six in the All-on-6 group (5%) and one in the All-on-4 group (1.25%), with no statistically significant differences (p = .246). No prosthetic failure occurred. Both group experienced some technical and biologic complications with no statistically significant differences between groups (p = .501). All-on-4 treatment concept demonstrated a trend of more complications during the entire follow-up period. A trend of more implant failure was experienced for the All-on-6 treatment concept. Marginal bone loss (MBL) from baseline to the 5-year follow-up was not statistically different between All-on-4 (1.71 ± 0.42 mm) and All-on-6 (1.51 ± 0.36 mm) groups (p = .12). For periodontal parameters, there were no differences between groups (p > .05). CONCLUSION: Both approaches may represent a predictable treatment option for the rehabilitation of complete edentulous patients in the medium term. Longer randomized controlled studies are needed to confirm these results.

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Restoration of the atrophic edentulous maxilla and mandible with implant retained prostheses has involved the use of axially placed implants in regions of the maxilla and mandible based on the adequate availability of bone, often using a staged surgical approaches. Anatomic limitations including pneumatized maxillary sinus, proximity of the inferior alveolar nerve and lack of available native bone have many clinicians performing traditional grafting procedure prior to implant placement. Utilization of the "All-on-4" concept has overcome these anatomic restrictions by allowing placement of 2 vertical and 2 angled implants in the premaxilla and anterior mandible. This technique has enabled immediate placement of full arch fixed restoration at the time of implant surgery if sufficient torque is achieved. It has biomechanical advantages including increasing in A-P spread, enhancing load distribution with cross arch stabilization, shorten cantilever, longer implants to be placed by titling them posteriorly, and maintenance of marginal bone height. High implant survival rates of in the maxilla (92.5-100%), in the mandible (93-100%) and restoration (99.2-100%) prove that the "All-on-4" concept is a viable treatment option for edentulous patients with atrophic alveolar ridges circumventing these traditional grafting procedures.

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Immediate function requires adequate implant stability. Immediate function requires prosthetic stability, particularly when multiple implants are loaded. Factors to consider for immediate implants into extraction sites are thickness of socket walls, thickness of gingival drape, optimal position of the implant, and patient factors such as hygiene and smoking cessation.

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