Distal Tilted Implants Research Articles

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

BackgroundCurrently, 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.MethodsTwo 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.ResultsUnder 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.ConclusionBoth 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.

Distally Tilted Implants According to the All-on-Four® Treatment Concept for the Rehabilitation of Complete Edentulism: A 3.5-Year Retrospective Radiographic Study of Clinical Outcomes and Marginal Bone Level Changes.

Bone grafting procedures during the use of dental implants may be avoided by the use of tilted implants in the maxilla and the mandible; advantages of angled implants are associated with the extension of the distal cantilever, leading to better implant survival rates. However, the bending effect on the single tilting implants may increase the marginal bone stress. The purpose of the present study was to retrospectively assess the clinical success and proximal bone loss rate following the implantation of distally tilted implants according to the All-on-Four™ prosthetic concept—based on radiographic findings—in a single-center experience, in addition to the assessment of the outcomes in the context of various clinico-epidemiological correlates. During the study period, n = 36 patients (24 males and 12 females) with complete records of periapical radiographs, received a full-arch fixed bridge supported by two axial and two distal tilted implants; overall n = 144 and n = 144 implants (Nobel B) were place in the maxilla and mandibles of patients, respectively. Mean age of patients at the time of fixture installation was 58.75 ± 13.71 years; n =11 patients presented with relevant underlying conditions/habits. To assess peri-implant bone-level changes, matched and calibrated orthopantomogram (OPT) images were taken at follow-ups after 1.5 years, 2.5 years, and 3.5 years post-restoration, and marginal bone levels were assessed on the mesio- (MA) and disto-approximal (DA) aspects. All implants were successful, resulting in a 100% overall survival rate. The radiographic mean bone loss levels at baseline (mean ± SEM) were 0.181 ± 0.011 mm and 0.178 ± 0.017 mm in the maxilla and mandible, respectively, while by the 3.5-year mark, bone loss was 0.770 ± 0.029 mm and 0.713 ± 0.026 mm in the maxilla and mandible (p > 0.05), respectively; bone-level changes were significant over time (p = 0.035 and p = 0.033). Peri-implant bone loss was more aggressive around titled distal implants versus mesial actual position implants. The effect of smoking and other underlying conditions showed significantly higher (p < 0.05) bone resorption levels when assessed on an individual implant-level, while during patient-level analysis, only a tendency was shown for higher bone loss rates for both MA and DA implants (p > 0.05). Within its limitations, our study has concluded that the use of All-on-Four™ prosthetic concept for total arch rehabilitation yields higher bone loss in association with tilted implants and, in some cases, on the MA surfaces at vertically positioned implants after >40 months in function.

All‐on‐4 immediate function concept

Background Nowadays the immediate loading procedure for the rehabilitation of edentulous jaws using osseointegrated implants has gained popularity among clinicians. However, the rehabilitation of edentulous jaws is often complicated by poor bone quality, especially in the posterior region and reduced bone volume due to longterm edentulism. Several clinical studies have reported that tilting of the implants may represent feasible treatment option. Such technique has several surgical and prosthetic advantages Aim/Hypothesis The purpose of this study was to prospectively evaluate the clinical and radiographic outcomes of immediate function of four implants supporting a fixed prosthesis in the completely edentulous jaws. Material and Methods This clinical case series included 10 patients with 72 immediately loaded implants (10 maxillary and 8 mandibular arch). Each patient received a full-arch fixed prosthesis supported by two distal tilted implants and two anterior axially placed implants. The provisional functional acrylic prosthesis and loading was applied within 48 hours from surgery. The patients were evaluated clinically and radiographically at implant placement, at 18 month follow-up examinations. Implant survival and prosthesis success were assessed. At follow-up plaque and bleeding score was assessed and radiographic evaluation of marginal bone level was performed. Results One immediately loaded tilted implant were lost in one patient before the 6-month follow-up. A total of 17 immediately loaded prostheses (10 in the maxilla and 7 in the mandible) were in function for at 18 months and were considered for the clinical examination. No further implant failure occurred to date. Total implant survival at 18 months was 98.6% (100% and 96.8% for the maxilla and the mandible, respectively). Marginal bone loss at 1 year averaged 0.59 mm in axial implants and 0.61 mm in tilted implants. 2 patients had a fracture of the provisional restoration, but all of the definitive prostheses remained stable throughout the study period without any complications. Conclusion and Clinical Implications The results of this clinical study show that the ìAll on Fourî immediate function concept is a viable treatment modality for the atrophic maxillae and mandibulae and there does not seem to be a different clinical outcome between tilted and axial implants.

Mandibular Full‐Arch Fixed Prostheses Supported on 4 Implants with Either Axial Or Tilted Distal Implants: A 3‐Year Prospective Study

This prospective study evaluated the clinical and radiographic outcome of distally cantilevered 4-implant-supported fixed mandibular prostheses (4-ISFMP) with distal implants either in axial or distally tilted direction. Forty-one mandibulary edentulous patients received acrylic veneered 4-ISFMP with casted framework. Based on distal implant placement direction patients were assigned to 2 groups: 21 patients with four (2 anterior/2 posterior) axial implants (axial-group I) and 20 patients with 2 anterior axial/2 distal tilted implants (tilted-group II). Patients were prospectively followed for 3 years by annual examinations of implants and prosthetic survival rates including assessment for biological and mechanical complications. Additionally, peri-implant marginal bone resorption [MBR], pocket depth [PD], plaque index [PI], bleeding index [BI] and gingival index [GI], and calculus index [CI] were evaluated at each annual follow-up. 37/41 patients (19 axial-group I, 18 tilted-group II) and 148/164 implants were followed at the 1-, 2-, and 3-year evaluation (dropout rate: 11.8%) presenting no implant and denture loss (100% survival). The overall, MBR at year 1, 2, and 3 was 1.11 ± 0.4 mm, 1.26 ± 0.42 mm, and 1.40 ± 0.41 mm, respectively, representing a significant (p < .001) continuing time depending annual reduction. MBR and PD did not differ between anterior and posterior regions in both groups or for anterior and posterior regions between the groups. PI and CI were significantly (p < .001) higher for implants in anterior regions than for posterior regions in both groups. Moreover, posterior implant regions showed significantly (p < .001) higher PI and CI for axial-group I than for tilted-group II over time. Biological and mechanical complications as well as GI and BI did not differ between the groups over a 3-year follow-up period. For clinical implant and prosthesis outcome no statistical significant mean differences were noted for distally cantilevered 4-ISFMP supported by distal implants placed in tilted or axial direction.

Effects of pulsed electromagnetic fields on swelling and pain after implant surgery: a double-blind, randomized study

The aim of this split-mouth, double-blind, randomized study was to determine whether pulsed electromagnetic field therapy (PEMF) can improve swelling and the management of pain after full-arch immediate loading implant surgery. Eleven patients were selected for the study. Each patient received four distal tilted implants in the upper or lower jaw and underwent full-arch immediate loading rehabilitation. After surgery, two PEMF devices were applied to each patient, one on each cheek. In a random manner, one of these PEMF devices was switched on (test side); the other served as a placebo (control side). Forty-eight hours after surgery clinicians estimated postoperative swelling through photographic documentation, comparing the condition before and after surgery, while pain was assessed using a verbal rating scale. The patient's degree of comfort in relation to the PEMF devices was analyzed by questionnaire using a numerical rating scale. No statistically significant difference was observed between the test and control sides for swelling or pain (P>0.05). Most of the patients did not present swelling or pain at 48h after surgery, regardless of whether the PEMF device was activated or not. Various outcomes were found in the comfort evaluation. Within the limitations of this study, PEMF does not reduce postoperative swelling or pain after implant surgery.

Prevalence of Peri-Implant Mucositis and Peri-Implantitis in Patients Treated with a Combination of Axial and Tilted Implants Supporting a Complete Fixed Denture.

Objectives. The aim of this retrospective study was to assess the incidence and prevalence of peri-implant mucositis and peri-implantitis in patients with a fixed full-arch prosthesis supported by two axial and two tilted implants. Materials and Methods. Sixty-nine patients were included in the study. Each patient received a fixed full-arch prosthesis supported by two mesial axial and two distal tilted implants to rehabilitate the upper arch, the lower arch, or both. Three hundred thirty-six implants for 84 restorations were delivered. Patients were scheduled for follow-up visits every 6 months in the first 2 years and yearly after. At each follow-up visit peri-implant mucositis and peri-implantitis were diagnosed if present. Results. The overall follow-up range was from 12 to 130 months (mean 63,2 months). Three patients presented peri-implantitis. The prevalence of peri-implant mucositis ranged between 0 and 7,14% of patients (5,06% of implants) while the prevalence of peri-implantitis varied from 0 to 4,55% of patients (3,81% of implants). Conclusions. The prevalence and incidence of peri-implant mucositis and peri-implantitis are lower than most of the studies in literature. Therefore this kind of rehabilitation could be considered a feasible option, on the condition of adopting a systematic hygienic protocol.

Immediate Rehabilitation of the Extremely Atrophic Mandible with Fixed Full‐Prosthesis Supported by Four Implants

To prospectively assess the outcome of immediate rehabilitation of extremely atrophic mandibles by a full-arch fixed bridge anchored to four implants. 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. 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. This technique could be considered a viable treatment option for the rehabilitation of the atrophic mandible.

Maxillary Sinus in relation to Modern Oral and Maxillofacial Surgery

Maxillary Sinus in relation to Modern Oral and Maxillofacial Surgery

Tilted Implants for Full-Arch Rehabilitations in Completely Edentulous Maxilla: A Retrospective Study

Purpose. The aims of this study were to assess the treatment outcome of immediately loaded full-arch fixed bridges anchored to both tilted and axially placed implants in the edentulous maxilla and to evaluate the incidence of biological and prosthetic complications. Materials and Methods. Thirty-four patients (18 women and 16 men) were included in the study. Each patient received a maxillary full-arch fixed bridge supported by two axial implants and two distal tilted implants. A total of 136 implants were inserted. Loading was applied within 48 hours of surgery and definitive restorations were placed 4 to 6 months later. Patients were scheduled for followup at 6, 12, 18, and 24 months and annually up to 5 years. At each followup plaque level and bleeding scores were assessed and every complication was recorded. Results. The overall follow-up range was 12 to 73 months (mean 38.8 months). No implant failures were recorded to date, leading to a cumulative implant survival rate of 100%. Biological complications were recorded such as alveolar mucositis (11.8% patients), peri-implantitis (5.9% patients), and temporomandibular joint pain (5.9% patients). The most common prosthetic complications were the fracture or detachment of one or multiple acrylic teeth in both the temporary (20.6% patients) and definitive (17.7% patients) prosthesis and the minor acrylic fractures in the temporary (14.7% patients) and definitive (2.9% patients) prosthesis. Hygienic complications occurred in 38.2% patients. No patients' dissatisfactions were recorded. Conclusions. The high cumulative implant survival rate indicates that this technique could be considered a viable treatment option. An effective recall program is important to early intercept and correct prosthetic and biologic complications in order to avoid implant and prosthetic failures.

Bone Level Changes Around Axial and Tilted Implants in Full‐Arch Fixed Immediate Restorations. Interim Results of a Prospective Study

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. 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. 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. 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 edentulous jaws with full fixed prostheses supported by four implants: interim results of a single cohort prospective study

The purpose of this study was to prospectively evaluate the clinical and radiographic outcomes of immediately loaded full-arch fixed prostheses supported by a combination of axially and non-axially positioned implants in a large cohort of patients with completely edentulous jaws, up to 5 years of function. One hundred and seventy-three edentulous patients (80 males and 93 females) were enrolled according to specific selection criteria. Each patient received a full-arch fixed prosthesis supported by two distal tilted implants and two anterior axially placed implants. The provisional functional acrylic prosthesis was delivered the same day as surgery in all cases. All cases were finalized 4-6 months later. The patients were scheduled for follow-up at 6 and 12 months of function, and annually up to 5 years. At each follow-up plaque and bleeding score was assessed and radiographic evaluation of marginal bone level was performed. The overall follow-up range was 4-59 months. A total of 154 immediately loaded prostheses (61 in the maxilla and 93 in the mandible) were in function for at least 1 year and were considered for the analysis. Four axially placed implants failed in the maxilla and one tilted implant in the mandible, all within 6 months of loading. No further implant failure occurred to date. Implant survival at 1 year was 98.36% and 99.73% for the maxilla and the mandible, respectively. Marginal bone loss at 1 year averaged 0.9+/-0.7 mm in the maxilla (204 implants) and 1.2+/-0.9 mm in the mandible (292 implants). No difference was found in marginal bone loss between axial and tilted implants. Plaque and bleeding scores progressively improved from 6 to 12 months. Fracture of the acrylic prosthesis occurred in 14% of total cases. The present preliminary results from a relatively large sample size suggest that the present technique can be considered a viable treatment option for the immediate rehabilitation of both mandible and maxilla.

Immediate Rehabilitation of the Mandible with Fixed Full Prosthesis Supported by Axial and Tilted Implants: Interim Results of a Single Cohort Prospective Study

The aims of this prospective study were to assess the treatment outcome of immediately loaded full-arch fixed bridges anchored to both tilted and axially placed implants for the rehabilitation of the mandible and to compare the outcome of axial versus tilted implants. Sixty-two patients (34 women and 28 men) were included in the study. Each patient received a full-arch fixed bridge supported by two axial implants and two distal tilted implants (All-on-Four, Nobel Biocare AB, Göteborg, Sweden). Loading was applied within 48 hours of surgery. Patients were scheduled for follow-up at 6, 12, 18, and 24 months, and annually up to 5 years. At each follow-up, plaque level and bleeding scores were assessed; moreover, patient's satisfaction for aesthetics and function was evaluated by a questionnaire. Radiographic evaluation of marginal bone level change was performed at 1 year. The overall follow-up range was 6 to 43 months (mean 22.4 months). Forty-four patients were followed for a minimum of 1 year. No implant failures were recorded to date, leading to a cumulative implant survival and prosthesis success rate of 100%. Plaque level and bleeding scores showed progressive decrease over time, parallel to increase of satisfaction for both aesthetics and function. No significant difference in marginal bone loss was found between tilted and axial implants at 1-year evaluation. The present preliminary data suggest that immediate loading associated with tilted implants could be considered a viable treatment modality for the mandible.

Immediate occlusal loading and tilted implants for the rehabilitation of the atrophic edentulous maxilla: 1‐year interim results of a multicenter prospective study

The aims of this prospective study were to assess the treatment outcome of immediately loaded full-arch fixed bridges anchored to both tilted and axially placed implants for the rehabilitation of fully edentulous maxillae and to compare the outcome of axial vs. tilted implants. Forty-one patients with edentulous maxillae were included in the study. Each patient received a full-arch fixed bridge supported by four axial implants and two distal tilted implants. Loading was applied within 48 h from surgery. Patients were scheduled for follow-up at 6 months, 1 year and annually up to 5 years. Radiographic evaluation of marginal bone-level change was performed at 1 year. One patient died 4 months after surgery. Thirty patients were followed for a minimum of 1 year (range 3-42 months, mean 22.1 months). Three failures were recorded at 1-year follow-up (two axial implants and one tilted). Two more implants (one tilted and one axially placed) were lost within 18 months of loading. The 1-year implant survival rate was 98.8% for both axial and tilted implants. Prosthesis success rate was 100% at 1 year. Marginal bone loss around axial and tilted implants at 12-month evaluation was similar, being, respectively, 0.9+/-0.4 (standard deviation) mm and 0.8+/-0.5 mm. The present preliminary data suggest that immediate loading associated with tilted implants could be considered to be a viable treatment modality for the atrophic maxilla and that there does not seem to be a different clinical outcome between tilted and axial implants.