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

OBJECTIVES: 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. MATERIAL AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.     

Clinical outcome of 103 consecutive zygomatic implants: a 6-48 months follow-up study

The purpose of this study was to evaluate retrospectively, after a period of 6-48 months follow-up of prosthetic loading, the survival rate of 103 zygomatic implants inserted in 55 totally edentulous severely resorbed upper jaws. Fifty-five consecutive patients, 41 females and 14 males, with severe maxillary bone resorption were rehabilitated by means of a fixed prosthesis supported by either 1 or 2 zygomatic implants, and 2-6 maxillary implants. This retrospective study calculated the success and survival rates at both the prosthetic and implant levels. Out of 55 prostheses, 52 were screwed on top of the implants, while 3 were modified due to loss of standard additional implants and transformed in semimovable prosthesis. Although osseointegration in the zygomatic region is difficult to evaluate, no zygomatic implant was considered fibrously encapsulated and they are still in function. This study confirms that zygoma bone can offer a predictable anchorage and support function for a fixed prosthesis in severely resorbed maxillae.     

A prospective clinical study on titanium implants in the zygomatic arch for prosthetic rehabilitation of the atrophic edentulous maxilla with a follow-up of 6 months to 5 years

Background Prosthetic rehabilitation with implant‐supported prostheses in the atrophic edentulous maxilla often requires a bone augmentation procedure to enable implant placement and integration. However, a rigid anchorage can also be achieved by using so‐called zygomatic implants placed in the zygomatic arch in combination with regular implants placed in residual bone. Purpose The aim of the present study was to report on the clinical outcome of using zygomatic and regular implants for prosthetic rehabilitation of the severely atrophic edentulous maxilla. Materials and Methods Sixty‐nine consecutive patients with severe maxillary atrophy were, during a 5‐year period, treated with a total of 69 fixed full‐arch prostheses anchored on 435 implants. Of these, 131 were zygomatic implants and 304 were regular implants. Fifty‐seven bridges were screw‐retained and 12 were cemented. The screw‐retained bridges were removed at the examination appointments and each implant was tested for mobility. In addition, the zygomatic implants were subjected to Periotest^® (Siemens AG, Bensheim, Germany) measurements. The patients had at the time of this report been followed for at least 6 months up to 5 years in loading. Results Two regular implants failed during the study period giving a cumulative survival rate of 99.0%. None of the zygomatic implants was removed. All patients received and maintained a fixed full‐arch bridge during the study. Periotest measurements of zygomatic implants showed a decreased Periotest values value with time, indictating an increased stability. Three patients presented with sinusitis 14–27 months postoperatively, which could be resolved with antibiotics. Loosening of the zygomatic implant gold screws was recorded in nine patients. Fracture of one gold screw as well as the prosthesis occurred twice in one patient. Fracture of anterior prosthetic teeth was experienced in four patients. Conclusions The results from the present study show that the use of zygomatic and regular implants represents a predictable alternative to bone grafting in the rehabilitation of the atrophic edentulous maxilla.     

Implants in the zygomatic bone for maxillary prosthetic rehabilitation: a systematic review

The purpose of this systematic review was to evaluate clinical studies on the follow-up survival of implants inserted in the zygomatic bone for maxillary rehabilitation. A comprehensive search of studies published from 2000 to July 2012 and listed in the PubMed/MEDLINE, Embase, and Cochrane Library databases was performed in accordance with the PRISMA statement. Relevant studies were selected according to predetermined inclusion and exclusion criteria. The initial database search yielded 751 titles. After filtering, 313 abstracts were selected, culminating in 42 full text articles. Application of eligibility criteria led to the elimination of 17 articles. Hence 25 full-text articles were considered clinically relevant and were included. Calculations of the interval survival rates and cumulative survival rates of implants could be carried out on the data extracted from the final list of included studies for the different time intervals. These studies reported the insertion of a total of 1541 zygomatic implants and 33 implant failures. Failure generally occurred during the first year interval and was related to clinical complications, such as recurrent acute and chronic sinusitis. After a 36-month follow-up, the survival rate was 97.86%. Additional studies with longer follow-up periods, including the number of zygomatic implants inserted and details of the variations in the surgical techniques used and the impact of the maxillary morphology are still required.     

“All-on-four” concept and immediate loading for simultaneous rehabilitation of the atrophic maxilla and mandible with conventional and zygomatic implants

We report the simultaneous rehabilitation of an edentulous patient with a hybrid (zygomatic and conventional implants) all-on-four implant-supported prosthesis for the maxilla and a standard (conventional implants) all-on-four implant-supported prosthesis for the mandible. The transfer impression was made with a multifunctional guide and the upper and lower prostheses were placed 24 h postoperatively. Clinical and radiographic examinations showed no infection or bony resorption 2 years later. Simultaneous maxillary and mandibular rehabilitation with all-on-four immediate loading is a viable, fast and effective option for edentulous patients.     

Tomographic evaluation of iliac crest bone grafting and the use of immediate temporary implants to the atrophic maxilla

Sixteen consecutive patients with atrophic maxillae, who had been referred for bone augmentation using iliac bone grafting before the placement of dental implants, received a full clinical examination and underwent a CT scan before and after surgery. Linear vertical and horizontal measurements were made before and 6 months after surgery. Differences in mean bone gain or loss for each area were compared between a group that received an immediate total provisional prosthesis on temporary immediate implants (test group, 12 patients) and a control group (four patients). Both groups showed significant horizontal bone gain in all regions and vertical bone augmentation in the posterior regions. The test group showed no significant difference for bone gain compared to the control group, but half the test group had problems during treatment. Bone augmentation of the atrophic maxilla with iliac crest bone grafting resulted in sufficient vertical and horizontal bone augmentation to install six or eight implants in all patients and successfully rehabilitate them. The results suggest that the use of total provisional prostheses on temporary immediate implants meets the aesthetic demands required, but should be used with care and in special cases.     

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

Objectives: 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. Materials and methods: 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. Results: 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. Conclusions: 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. To cite this article:
Agliardi E, Panigatti S, Clericò M, Villa C, Malò P. Immediate rehabilitation of the edentulous jaws with full fixed prostheses supported by four implants: interim results of a single cohort prospective study.
Clin. Oral Impl. Res. 21 , 2010; 459–465.
doi: 10.1111/j.1600‐0501.2009.01852.x     

Computer-guided flapless placement and immediate loading of four conical screw-type implants in the edentulous mandible

AIM: The aim of this prospective study was to evaluate the outcome of computer-guided flapless placement and immediate loading of four conical screw-type implants in the interforaminal region. PATIENTS AND METHODS: From May to August 2003, 25 consecutive patients (m : f=16 : 9) with edentulous mandibles were included in the study. After transmucosal drilling with computer-assisted navigation, four implants were placed in the interforaminal region. The lower dentures were converted and implants immediately loaded. RESULTS: One-hundred implants were successfully placed. In two patients, all implants had to be submerged because of insufficient primary stability of one of the implants; another patient declined to receive immediate loading of implants after surgery and was lost to follow-up. During follow-up of the remaining 22 patients with 88 immediately loaded implants, loosening of four implants (4.5%) was seen in three patients. In these cases, immediate loading was terminated and all implants submerged; subsequently, two implants were lost in one patient, while the other two implants re-osseointegrated. The cumulative survival and success rates of immediately loaded implants were 97.7% after 2 years. Prosthetic success was 100%. CONCLUSION: Transmucosal computer-assisted placement and immediate loading of mandibular implants is a high-end approach to edentulism that provides excellent results while being minimally invasive.     

Immediate loading of implants in the edentulous maxilla: use of an interim fixed prosthesis followed by a permanent fixed prosthesis: a 32-month prospective radiological and clinical study

Purpose: The aim of this study was to prospectively evaluate the survival rate of splinted and immediately loaded Straumann sandblasted, large-grit, acid-etched, solid-screw dental implants in the edentulous maxilla after 32 months of loading.
Materials and Methods: Twenty-eight patients (mean age 63 years) with edentulous maxillae received 168 implants (six each) and an implant-supported fixed interim prosthesis within 24 hours after surgery. After a mean healing time of 15 weeks, the patients received permanent screw-retained prostheses. Clinical and radiological examinations were made at implant placement and after 8, 20, and 32 months of loading. All permanent prostheses were removed at the 32-month follow-up; implant stability was checked with a torque device, and the implant stability quotient was determined with resonance frequency analysis.
Results: Mean marginal bone loss from baseline to 8 months after loading was 1.6 mm (SD 1.16; p  = .094), from 8 to 20 months 0.41 mm (SD 0.63; p  = .094), and from 20 to 32 months 0.08 mm (SD 0.49; p  = .039). The 32-month cumulative survival rate was 98.2%.
Conclusions: The 32-month survival of solid-screw implants – immediately loaded within 24 hours after placement – was similar to survival rates reported for solid-screw implants with conventional loading. Immediate loading and splinting of implants in the edentulous maxilla is a viable treatment alternative.     

Report of a case receiving full-arch rehabilitation in both jaws using immediate implant loading protocols: a 1-year resonance frequency analysis follow-up

Background: Immediate occlusal implant loading has been documented as a viable treatment option for various indications. However, documentations related to full‐arch rehabilitation are usually limited to treatment of one jaw at a time, thereby leaving the opposing dentition unchanged. Furthermore, clinical documentation using traditional, well‐accepted measuring techniques may not be adequate when it comes to short‐term evaluation of the success or failure of implants subjected to immediate occlusal loading. Purpose: The purpose of this case report is to (1) present an implant stability follow‐up of a patient receiving an immediate, implant‐supported full‐arch rehabilitation in both jaws and (2) evaluate the patient's acceptance of this rehabilitation. Materials and Methods: A 68‐year‐old patient scheduled for implant treatment was selected for an immediate implant loading protocol in both jaws. During two surgical events 3 weeks apart, eight maxillary and four mandibular Brånemark System® Mk IV TiUnite^TM fixtures (Nobel Biocare AB, Göteborg, Sweden) were inserted and subsequently used to immediately support a cross‐arch fixed prosthesis in the maxilla and a bar‐retained overdenture in the mandible. Implant stability was recorded from the day of surgery periodically during a 1‐year follow‐up using resonance frequency analysis (RFA). Results: At the 1‐year follow‐up, based on clinical, RFA, and radiographic evaluations, all implants and the reconstructions were classified as successful. All maxillary implants showed a decrease in the implant stability quotient (ISQ) value from the measurement at the time of surgery to the first follow‐up, whereas two of four mandibular implants revealed an initial drop in stability. Irrespective of a specific ISQ level measured at implant surgery (ISQ range 53–74) and despite an initial decrease in stability, measurements recorded at the 12‐month follow‐up indicated similar stability levels for all maxillary implants (ISQ range 64–68) or the group of mandibular implants (ISQ range 72–75) but with a higher ISQ level for mandibular implants. Furthermore, the patient's acceptance of the immediate full‐arch rehabilitation in both jaws was high. Conclusions: The present case report demonstrates that a slightly staged approach for full‐arch rehabilitation in both jaws using immediate implant loading protocols is a realistic treatment option. Furthermore, RFA follow‐up indicates that immediately occlusally loaded implants placed in reduced bone quality and quantity are more prone to loose stability in the early healing period compared with implants placed in dense bone quality.     

Considerations preliminary to the application of early and immediate loading protocols in dental implantology

In oral implantology, a 3–6 month stress‐free healing period is presently accepted as a prerequisite to achieve bone apposition without interposition of a fibrous scar tissue. This protocol was introduced by Brånemark and co‐workers in 1977. The aim of the present paper is to review the reasons that led Brånemark and collaborators to require long delayed loading periods. It is shown that the requirement for long delayed loading periods was drawn from the initiation and development periods of their original clinical trial. Demanding conditions were met involving simultaneously: 1) patients with poor bone quality and quantity, 2) non‐optimized implant design, 3) short implants, 4) non‐optimized surgical placement, 5) non‐optimized surgical protocol and 6) biomechanically non‐optimized prosthesis. Extrapolation of the requirement for long healing periods from these particular conditions to more standard situations involving refined surgical protocols and careful patient selection might be questioned. Albeit premature loading has been interpreted as inducing fibrous tissue interposition, immediate loading per se is not responsible for fibrous encapsulation. It is the excess of micromotion during the healing phase that interferes with bone repair. A threshold of tolerated micromotion exists, that is somewhere between 50 μm and 150 μm. It is suggested that loading protocols might be shortened through 2 different approaches. The first way would be to decrease stepwise the delayed loading period for free‐standing implants below the presently accepted 3–6 months of healing. The second way would be to identify immediate loading protocols that are capable of keeping the amount of micromotion beneath the threshold of deleterious micromotion. Immediate loading protocols for implants‐retained overdentures and fixed bridges are reviewed. It is shown that successful premature loading protocols require a careful and strict patient selection aimed to achieve the best primary stability. These various protocols need to be further documented in order to assess their predictability.     

Long-term clinical outcomes of immediate loading versus non-immediate loading in single-implant restorations: a systematic review and meta-analysis

Dental implant restoration is a predictable treatment option for replacing missing or damaged teeth. Conventional loading requires a prolonged treatment period and second surgical interventions. The aim of this study was to compare the clinical outcomes between immediate and non-immediate (early or conventional) loading in single-implant restorations. A literature search of the PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov databases was performed in January 2020. Only randomized clinical trials (RCTs) were included. The overall risk ratios (RRs), mean differences (MDs), and 95% confidence intervals (CIs) were used in the analyses. A total of 10 RCTs reporting on 423 patients were included. There was no significant difference in any of the outcomes of interest between the immediate and non-immediate loading cases: implant failure at the patient level (RR 1.29, 95% CI 0.35 to 4.78, P = 0.71), implant failure at the implant level (RR 1.19, 95% CI 0.40 to 3.51, P = 0.75), marginal bone loss (MD ?0.04, 95% CI ?0.16 to 0.08, P = 0.54). Subgroup analyses showed similar results. Immediate loading had predictable long-term clinical outcomes if the indicated patients were carefully selected. The influences of several technical factors need to be confirmed in additional clinical trials.     

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.