The term All-on-4, also known as All‐on‐Four and All‐in‐Four, refers to 'all' teeth being supported 'on four' dental implants, a prosthodontics procedure for total rehabilitation of the edentulous (toothless) patient, or for patients with badly broken down teeth, decayed teeth, or compromised teeth due to gum disease. It consists of the rehabilitation of either edentulous or dentate maxilla and / or mandible with fixed prosthesis by placing four implants in the anterior maxilla, where bone density is higher. The four implants support a fixed prosthesis with 10 to 14 teeth, and it is placed immediately, typically within 24 hours of surgery.
Implant manufacturer Nobel Biocare AB of Gothenburg, Sweden, was among the first to identify the evolution of the All-on-4 technique as a potential valid and cost-effective alternative to conventional implant techniques, and funded studies by Portuguese dentist Paulo Maló to determine the efficacy of this approach. During this time, this technique was also used by various other clinicians around the world.
All-on-4 is not an invention, but rather a treatment technique that has evolved over time, and has the following features:
- four dental implants to support a full fixed bridge (documented since 1977)
- the use of angulated implants in the back to overcome bony deficiencies or anatomical structures (documented since 1990)
- immediate loading (documented since 1990)
The All-on-4 treatment concept is a prosthodontic procedure (i.e replacement of missing teeth) that provides a permanent, screw-retained, same-day replacement for the entire upper and / or lower set of teeth with a bridge or denture. The procedure is best for patients with significant tooth loss or decay, and for people whose bone loss in the jaw area prevents them from getting conventionally oriented (vertical) dental implants. Often, tooth loss is accompanied by loss of the jaw bone, which poses the problem of reconstruction of the jaw bone requiring bone grafting. The All-on-4 technique takes advantage of the dense bone that remains in the front part of the jaws, and by placing the two posterior implants on an angle to avoid the sinus cavities in the upper jaw and the nerve canal in the lower jaw. The cost of the All on 4 procedure varies based on the final prosthetic material. Acrylic resin teeth over titanium bar is substantially cheaper resulting in a total cost of around $30K per arch/jaw in the United States. Premium prosthetic materials like Zirconia can result in a total treatment cost between $36K to $40k per arch/jaw in the United States. For the implementation to be successful a careful analysis of the bone structure needs to be made. The most ideal way to evaluate the bone is by a cone beam computed tomography (CBCT) scan. The All-on-4 protocol is for at least four implants to be placed in a jaw. The back implants are typically angled approximately 30 to 45 degrees from the occlusion (biting plane). The implant is placed in front of the maxillary sinus in the upper jaw (maxilla), and in front of the mental nerve in the lower jaw (mandible). The head of the implant emerges in approximately the second premolar position. This will allow a molar tooth to be cantilevered posterior, resulting in a denture or bridge with approximately twelve teeth.
- Maló, Paulo; Rangert, Bo; Nobre, Miguel (March 2003). "'All-on-Four' immediate-function concept with Brånemark System implants for completely edentulous mandibles: a retrospective clinical study". Clinical Implant Dentistry and Related Research. 5 (s1): 2–9. doi:10.1111/j.1708-8208.2003.tb00010.x. PMID 12691645.
- "השתלות שיניים בשיטת אול און פור / אול און 4 – פה מושלם ביום אחד" [All-in-four / All-on-4 dental implants - perfect mouth in one day]. www.MaloClinic.co.il (in Hebrew). Malo Clinic. Retrieved 19 February 2021.
- Patzelt SB, Bahat O, Reynolds MA, Strub JR (April 2013). "The all-on-four treatment concept: a systematic review". Clinical Implant Dentistry and Related Research. 16 (6): 836–855. doi:10.1111/cid.12068. PMID 23560986.
- Zhao X, DI P, Lin Y, Li JH, Qiu LX, Luo J, Cui HY (18 October 2014). "Implanting the edentulous jaws with 'All-on-4' immediate reconstruction: a preliminary clinical observation". Beijing Da Xue Xue Bao [Journal of Peking University (Health Sciences)]. 46 (5): 720–6. PMID 25331394.
- "All-on-4® treatment concept". www.NobelBiocare.com. Nobel Biocare Services AG. Retrieved 19 February 2021.
- Maló, Paulo; de Araújo Nobre, M; Lopes, A; Ferro, A; Botto, J (August 2019). "The All-on-4 treatment concept for the rehabilitation of the completely edentulous mandible: A longitudinal study with 10 to 18 years of follow-up". Clinical Implant Dentistry and Related Research. 21 (4): 565–577. doi:10.1111/cid.12769. PMID 30924309. S2CID 85565798.
- History and evolution of the All-on-4® treatment concept | Nobel Biocare. Paulo Malo on the evolution and history of the All-on-4® treatment concept, from Nobel Biocare's speaker forum at EAO 2013. Why did it take so long?. www.YouTube.com. Nobel Biocare. 8 November 2013. Retrieved 19 February 2021.
- Branemark, Per-Ingvar (1977). Osseointegrated implants in the treatment of the edentulous jaw: experience from a 10-year period – a description of a new procedure for rehabilitation of the edentulous patient and a clinical report of 235 jaws in 211 consecutive cases treated during 1965-1975 with installation of 1618 titanium fixtures supporting permanently bone anchored bridges. Scandinavian journal of plastic and reconstructive surgery. Stockholm, Sweden: Almquivist & Weksell International. pp. 79, 81, 83. ISBN 91-22-00128-X. OCLC 898915370. OL 18985290M.
- Kallus, T; Henry, P; Jemt, T; Jorneus, L (Spring 1990). "Clinical evaluation of angulated abutments for the Brånemark system: a pilot study". The International Journal of Oral & Maxillofacial Implants. 5 (1): 39–45. PMID 2202668.
- Lefkove, MD; Beals, RP (1990). "Immediate loading of cylinder implants with overdentures in the mandibular symphysis: the titanium plasma-sprayed screw technique". The Journal of Oral Implantology. 16 (4): 265–271. PMID 2098572.
- "Everything about All On 4 Dental Implamts".