Topic: All-on-Four Concept Literature Review

Review Article

Austin J Dent. 2023; 10(2): 1176.

Topic: All-on-Four Concept Literature Review

Ramazan Isufi1; Edit Xhajanka1*; Anis Thodhorjani1,2; Neada Hysenaj1,2; Fatmir Lela1; Silvana Bara1; Renato Isufi1,2

1Faculty of Dental Medicine, University of Medicine, Tirana, Albania

2University Dental Clinic, Tirana, Albania

*Corresponding author: Edit Xhajanka Faculty of Dental Medicine, University of Medicine, Tirana, Albania. Email: edit.xhajanka@umed.edu.al

Received: November 16, 2023 Accepted: November 24, 2023 Published: December 01, 2023

Introduction

In patients with total edentulism, dental implant treatment is a treatment model which has been accepted scientifically, and with long-term outcomes [1,2]. Dental implants with immediate function by making implant-supported fixed full-arch restorations are becoming the gold standard in dental implantology [3-5]. Normally in literature successful prostheses are made using [6-8] implants in the maxilla and 6 implants in the mandible and applying posterior cantilever extension where it is necessary, in these treatments, hygiene controls can be easily performed especially in full arch screw-retained fixed prostheses [7-9].

In some cases maxillary sinuses for maxilla restricts the implant placement in the posterior region. The posterior implant treatment is also difficult in patients with resorbed mandible with a mandibular nerve located at the top of the alveolar crest. The all-on-four implant concept has been developed to prevent these disadvantages presented by Malo for the first time in 2003 and the all-on-four concept that began to be used in atrophic full arch mandibular and in the maxilla in 2005. In this technique implants are positioned in the pre-maxillary region in the maxilla and in the inter-foraminal region in the mandible.Anterior implants are placed to the lateral incisor sites or canine/first premolar region, posterior implants are placed to the second premolar or first molar region [12-16].

The fact that full arch screw-retained fixed prostheses and immediate dentures made on a total of 4 implants including two implants that are orthogonally placed to the occlusal plane in the anterior region and two implants that are placed in the posterior region with a mesial angle of 30-45 grade in edentulous maxillary or mandibular jaws are constructed and immediately loaded (after a surgery of 8-48h), and the construction of permanent fixed prosthesis after a 3-month period constitute the basis of the all-on-four concept [21,22].

The fact that the distribution of the forces is biomechanically sufficient with 4 implants placed at right angles and positions, the use of longer implants for the posterior region (=13mm) and accordingly increase in bone anchorage and placement in the correct biomechanical position, and ensuring high primary stability are regarded as the advantages of the all-on-four concept [29,30].

In implant supported dentures, general protocol is formed by placing implants parallel to the anterior maxilla and mandible. In implant-supported fixed dentures, masticatory forces are distributed evenly over the implants, and the loads to be on posterior cantilever extensions are shared on many anterior implants. For this purpose, it is aimed to distribute the loads by increasing the number of maxillary and mandibular anterior implants [31-33].

In literature are many researches articles about the all-on-four implant concept. Therefore, the purpose of this review is to summarize articles written about all-on-four, to make comparisons between them, to form the advantages and disadvantages of the method from the literature review, and to evaluate the all-on-four concept in terms of osseointegration and crestal bone resorption [35-37].

Material and Methods

In this review, studies involving maxilla and mandible applications of the current all-on-four technique, its advantages and disadvantages, surgical technique, antero-posterior spread and osseointegration and clinical survival rates were examined.

In the review performed in Pubmed and Cochrane Library between 2005 and 2023, Full arch implant-supported prosthesis, 4-implant full arc, osseointegration, inclined implant, total edentulism and different combinations in which some of these keywords were used together were chosen. 100 of the articles achieved from the review were evaluated with respect to the subject we examined.

The inclusion criteria for articles were as follows:

1-Articles were related to the all-on-four concept,

2-Abstracts were obtained when the full texts could not be obtained.

General Considerations for All on Four:

1. The first concern in all on four procedure is to achieve the primary stability of minimum 35Ncm up to maximum of 45 Ncm.

2. There should be minimum 5mm of bone width present in the implant placement site

3. Minimum of 10mm of bone height should be available from canine to canine region in the maxillary arch and 8mm in the mandibular edentulous arch.

4. Splinting of tilted implants can be done if the angulation of the implants placed is more than 30 degree.

5. In case of tilted implants placed in the posterior edentulous region, the access hole to the distal screw should be located at occlusal face of first molar, second premolar and on the first premolar [35-39].

Surgical Technique

Two distal implants were placed in the maxillary posterior edentulous region and these two implants are tilted anterior to the maxillary sinus, on the other hand in the mandibular arch, implants have been placed anterior to the mental foramen region. These implants should be inserted at an angulation ranging between 30 degree to 45 degree. Surgical guide help in ensuring the correct positioning of the implant. The surgical guide should be placed in the osteotomy in the Centre position of the maxilla and the mandible. A band should be constructed of titanium should be contoured to follow the arc of the opposite arch. The lines which are present over the surgical guide act as a reference for the drilling at correct angulation and that angulation over the surgical guide should be or must be not greater than 45 degree.

Citation: Isufi R, Xhajanka E, Thodhorjani A, Hysenaj N, Lela F, et al. Topic: All-on-Four Concept Literature Review. Austin J Dent. 2023; 10(2): 1176.