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Table of Contents
Year : 2015  |  Volume : 5  |  Issue : 1  |  Page : 76-81

"All-On-4/DIEM 2" A concept to rehabilitate completely resorbed edentulous arches

1 Department of Prosthodontics, Dayananda Sagar Dental College and Research Center, Rajiv Gandhi University of Health Sciences, Bengaluru, Karnataka, India
2 Dayananda Sagar Dental College, Bengaluru, Karnataka, India

Date of Web Publication2-Apr-2015

Correspondence Address:
Minal Mahantshetty
Department of Prosthodontics, Dayananda Sagar College of Dental Sciences, Kumarswamy Layout, Banashankari, Bengaluru, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0974-6781.154455

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Although a number of approaches to implant-supported restoration of severely atrophic maxillae and mandibles have been developed, most of these treatments are costly and protracted. An exception is the all-on-four concept, which uses only four implants to support an acrylic, screw-retained provisional prosthesis delivered on the day of implant placement, followed by a definitive prosthesis later on. The present article describes about full-arch rehabilitations using implants supported prosthesis by "DIEM 2/all on 4" technique. This is an innovative technique that allows for immediate function, full arch implant-supported prosthesis without the need for any bone grafting procedures even in atrophic situations. In this technique, four implants are placed in the anterior region of the jaw between the two mental foramina in the mandible and between the mesial walls of maxillary sinus in the maxilla. The two anterior implants follow the jaw anatomy and the two distal implants are tilted at 45° angulation posteriorly, this arrangement allowed for good implant anchorage, short cantilever length, and large inter implant distance thus favoring fruitful outcome of the treatment.

Keywords: All-on-four concept, DIEM 2 concept, full-arch rehabilitation, tilting posterior implants

How to cite this article:
Thumati P, Reddy M, Mahantshetty M, Manwani R. "All-On-4/DIEM 2" A concept to rehabilitate completely resorbed edentulous arches. J Dent Implant 2015;5:76-81

How to cite this URL:
Thumati P, Reddy M, Mahantshetty M, Manwani R. "All-On-4/DIEM 2" A concept to rehabilitate completely resorbed edentulous arches. J Dent Implant [serial online] 2015 [cited 2023 Mar 23];5:76-81. Available from:

   Introduction Top

A common condition in elderly patients is the occurrence of edentulism, which can be the result of many factors such as poor oral hygiene, dental caries, and periodontal disease. The edentulous condition has been shown to have a negative impact on oral health-related quality of life. Clinicians are facing with the growing need to offer solutions to this population due to an increase in their life expectancy and to fabricate prostheses that provide a replacement for the loss of natural teeth, allowing optimum satisfaction and improved quality of life.

One of the most remarkable achievements in clinical dentistry is the immediate rehabilitation of a completely edentulous maxilla or mandible with a fixed prosthesis supported by implants. In edentulous condition desiring to have an implant-supported prosthesis with multiple implants may not be feasible in many cases because of the expense, anatomical structures in the vicinity and the quality and quantity of bone left. The all-on-four concept, a surgical and prosthetic protocol for immediate function involving the use of four implants to support a fixed prosthesis in patients with completely edentulous jaws is a viable long-term treatment protocol. [1]

In such a condition the DIEM 2/all-on-four treatment concept provides edentulous arches with an immediately loaded, fixed prosthesis using four implants: Two implants in the anterior region of the jaw which are oriented straight and 2 posterior implants, which are tilted distally.
"all-on-four" concept involves the use of four implants restored with straight and angled multiunit abutments, which support a provisional, fixed, and immediately loaded, full-arch prosthesis placed on the same day of surgery. "DIEM 2 concept" involves placing the four implants in both maxilla and the mandible and immediately loading them on the say day of the surgery.

The all-on-four/DIEM 2 treatment has been developed to maximize the use of available bone and allows immediate function. Overall, many long-term studies and published data on the all-on-four concept reported cumulative survival rates between 92.2% and 100%. [2]

Tilted implants were suggested to be useful in the treatment of edentulous arches because they avoided the bone augmentation procedures, anatomical structures and in order to reduce cantilever length there by reducing the stress and providing better stress distribution. [3]

The all-on-four concept/DIEM 2 concept for rehabilitation of completely edentulous ridges the concept was developed, institutionalized and systematically analyzed in the 1990's by a dentist Paulo Malo. [4],[5],[6]

The procedure consists of the rehabilitation of edentulous maxilla and mandible with fixed prosthesis by placing four implants in the anterior maxilla and four implant in the mandible between the interforaminal distance; where bone density is higher, leading to the highest success rate. The four implants support a fixed prosthesis with 12-14 teeth and it is immediately in function on the day of surgery. [1],[7]

   Case report Top

A 68-year-old male patient reported to our private practice with the chief complaint of loose and unstable dentures. An intraoral examination revealed resorption of maxillary and mandibular arches. He was referred for orthopantamograph and cone beam computed tomography imaging [Figure 1] and [Figure 2].
Figure 1: Pretreatment orthopantomograph showing edentulous maxilla and mandible

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Figure 2: Cone beam computed tomography section

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Radiological findings showed Fallschussel's Type 5 resorption in the Maxilla and Type 3 in the Mandible. Laboratory blood tests and bone mineral density test were performed to exclude osteoporosis. Blood analysis indicated that the parameters of interest (Calcium, Phosphorus, alkaline phosphatase etc.,) were within the reference limit.

Patient was educated about the different Prosthetic options as follows:

  • Implant-supported over dentures
  • Implant-supported fixed complete dentures after bone augmentation
  • Implant-supported fixed complete dentures supported by four implants using "all-on-four"/"DIEM 2" concept.

After understanding, the patient agreed for "all-on-four" concept because of economic issues (since less number of implants are used) and less surgical trauma. The treatment protocol was explained to the patient and also written consent was obtained from him prior to the procedure.

Surgical phase: All surgeries were performed under local anesthesia with lignocaine 2% adrenaline.

Surgical phase in the maxilla

  • Two implants of Biomet 3I (Global Headquarters, 4555 Riverside Drive, Plam Beach Gardens, FL 33410, USA) with dimensions of 13 mm length and 4 mm diameter were placed in the anterior maxilla parallel to the midline of the jaw
  • The two most posterior implants from the Biomet 3I of 13 mm length and 4 mm diameter were placed anterior to the mesial wall of the sinus. The posterior implants were tilted 45° distally. All the implants were placed with the guidance of the surgical guide [Figure 3].
Figure 3: Surgical guide for implant placement

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Surgical phase in the mandible

  • The two anterior implants with dimensions 13 mm length and 4 mm diameter are placed straight following jaw anatomy
  • The two most posterior implants with dimensions of 13 mm length and 4 mm diameter are placed by tilting distally at 45° angle. All the four implants are placed between the interforminal distance [Figure 4].
Figure 4: Implants placed in mandible

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Final torque and abutment fixture

  • To allow immediate loading and function, each implant was inserted with a final torque of 60-65 Ncm.
  • A 17° angulated abutments were attached on the distal implants with respect to the long axis of the fixture were positioned in such a way to obtain an optimal orientation for the prosthetic screw access, while straight abutments were placed over the anterior implants [Figure 5].
Figure 5: Orthopantomograph showing maxilla and mandible postimplant insertion

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Prosthetic phase

  • The silicone polysiloxane impression material (Denstsply Aquasil light body consistency) was placed on the tissue surface of the existing acrylic prosthesis (complete denture) and was placed intra-orally for indexing the position of the abutments.
  • Then, these indexed areas were drilled with a round bur to create the access holes in the denture, which could facilitate the seating of the denture completely [Figure 6] and [Figure 7]
  • Once the denture was checked for complete seating, the cylinders were connected to the low profile abutments and screws were tightened over the abutments [Figure 8]. The height of the cylinders was adjusted as needed for the prosthesis.
Figure 6: Indexing of implant position with elastomeric impression material

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Figure 7: Access holes drilled

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Figure 8: Cylinders attached

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Pick up of the cylinders

  • To prevent the irritation of monomer to the mucosa and flow of the resin into the unwanted areas, a sheet of latex was placed on the tissue surface of the denture [Figure 9] and [Figure 10] and then chemically activated resin (DPI-RR Cold cure) was added all around the cylinder areas and allowed to set [Figure 11]
  • Once the resin sets completely, denture was unscrewed and it was finished like a bridge framework.
Figure 9: Attachment of latex sheet

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Figure 10: Indexed prosthesis seated

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Figure 11: Resin is flown for picking up of cylinders

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Final insertion

  • Occlusion was equilibrated and it was polished
  • Soft tissue relining material was added on the tissue surface of the denture. Denture was placed intraorally, any excess of the relining material was trimmed
  • Final insertion was done [Figure 12] and [Figure 13] and the screw were tightened back in the patient's mouth. The access holes were covered with resin
  • The patient was advised for soft diet for 2 weeks. Regular follow-up was done to assess the treatment outcome.
Figure 12: Soft reline material added

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Figure 13: Patient with implant-supported fixed prosthesis

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   Discussion Top

The all-on-four/DIEM 2 immediate function concept for completely edentulous jaws has proven to be clinically effective, patient pleasing and applicable in many situations where otherwise more complicated procedures would have been indicated.

In patients with moderate to severe resorption of the edentulous lower jaw, in whom dental implants with standard dimensions cannot be placed due to the lack of available bone, other options should be considered.

Several approaches have been utilized till date, use of short implants (6 mm in length and 3 mm or even less in width), wedge-shaped implants, alveolar distraction osteogenesis, guided bone generation, use of transmandibular staple implants and use of intra- and extraoral autogenous bone grafts etc. The clinically documented technique of tilting posterior implants was developed for improving bone anchorage, prosthesis support and avoiding bone grafting procedures. [8]

Paul Malo did a retrospective clinical study using "all on four concept" in which 44 patients were placed with 176 immediately loaded implants, placed in the anterior region, supporting fixed complete-arch mandibular prostheses. Five immediately loaded implants were lost in five patients before the 6-month follow-up, giving cumulative survival rates of 96.7 and 98.2% for development and routine groups, respectively. The prosthesis survival rate was 100%, and the average bone resorption was very low. Finally, he concluded that the concept has high cumulative implant and prosthesis survival rates indicating that the "all on-four" immediate-function concept used in completely edentulous mandibles is a viable treatment concept. [4]

Kan et al. said that combining these 2 concepts, the all-on-four immediate-function concept is a simple, safe, and effective surgical and prosthetic protocol for immediate function (within 2 h) of four implants supporting a fixed prosthesis in a completely edentulous mandible. Recently, reported the integration of the all-on-four immediate-function concept with computer guided implant placement for the rehabilitation of completely edentulous jaws showed that this treatment modality can be predictable with a high implant survival rate. [9]

Zampelis et al. did a study to evaluate if tilting of splinted implants affects stress distribution in the bone surrounding the implant cervix, and to investigate if the use of tilted implants as distal abutments is biomechanically superior to the use of distal cantilevers using two-dimensional finite element analysis. Within the limitations they said that distal tilting of implants splinted by fixed restorations does not increase bone stress compared to normally placed, vertical implants. There is a biomechanical advantage in using tilted distal implants rather than distal cantilever units. [10]

The advantages of this technique are:

  • This technique allows to place longer implants making it possible to increase implant to bone interface and thus increasing the stability of the implants
  • Creating a wider distance between anterior and posterior implants resulting in better load distribution
  • Eliminating need for cantilevers in prosthesis by distal tilting of implants and need for bone augmentation.

   Conclusion Top

To conclude it can be said that "all-on-four concept"/"DIEM 2" allows the clinicians to plan optimal implant positions and accurately execute the plan. Well distributed implant positions translate to a biomechanically sound prosthesis supported by the least number of implants. The tilting of the distal implants supporting decreased cantilevered segments showed decreased peri implant stresses. The cantilever length reduction and distally tilted posterior implants associated with "all on four Concept" played an important role in decreasing the peri-implant stress thus promising better stress distribution and success of the treatment. It can be said that "all on four concept/DIEM 2" is a viable treatment modality, with the angled posterior implants allowing longer implants anchored in better quality bone, reduces posterior cantilever, eliminates bone grafts in the edentulous maxilla and mandible in majority of cases, Implants well-spaced, good biomechanics, and reduced cost due to less number of implants. Thus increasing the overall survival and success rate of the treatment in the edentulous patients.

   References Top

Malo P, de Araújo Nobre M, Lopes A, Moss SM, Molina GJ. A longitudinal study of the survival of All-on-4 implants in the mandible with up to 10 years of follow-up. J Am Dent Assoc 2011;142:310-20.  Back to cited text no. 1
Babbush CA, Kutsko GT, Brokloff J. The all-on-four immediate function treatment concept with NobelActive implants: A retrospective study. J Oral Implantol 2011;37:431-45.  Back to cited text no. 2
Cavalli N, Barbaro B, Spasari D, Azzola F, Ciatti A, Francetti L. Tilted implants for full-arch rehabilitations in completely edentulous maxilla: A retrospective study. Int J Dent 2012;2012:180379.  Back to cited text no. 3
Maló P, Rangert B, Nobre M. "All-on-Four" immediate-function concept with Brånemark System implants for completely edentulous mandibles: A retrospective clinical study. Clin Implant Dent Relat Res 2003;5 Suppl 1:2-9.  Back to cited text no. 4
Maló P, Rangert B, Nobre M. All-on-4 immediate-function concept with Brånemark System implants for completely edentulous maxillae: A 1-year retrospective clinical study. Clin Implant Dent Relat Res 2005;7 Suppl 1:S88-94.  Back to cited text no. 5
Maló P, Nobre Md, Lopes A. Short implants in posterior jaws. A prospective 1-year study. Eur J Oral Implantol 2011;4:47-53.  Back to cited text no. 6
Maló P, de Araújo Nobre M. Implants (3.3 mm diameter) for the rehabilitation of edentulous posterior regions: A retrospective clinical study with up to 11 years of follow-up. Clin Implant Dent Relat Res 2011;13:95-103.  Back to cited text no. 7
Maló P, de Araújo Nobre M, Lopes A, Francischone C, Rigolizzo M. "All-on-4" immediate-function concept for completely edentulous maxillae: A clinical report on the medium (3 years) and long-term (5 years) outcomes. Clin Implant Dent Relat Res 2012;14 Suppl 1:e139-50.  Back to cited text no. 8
Kan JY, Rungcharassaeng K, Oyama K. Computer-guided implant treatment with all-on-four immediate-function concept. Contemp Esthet 2007.  Back to cited text no. 9
Zampelis A, Rangert B, Heijl L. Tilting of splinted implants for improved prosthodontic support: A two-dimensional finite element analysis. J Prosthet Dent 2007;97:S35-43.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13]

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