10.59987/ads/2014.4.142-145
The “All-on-Four” concept is based on the placement of four implants in the anterior part of fully edentulous jaws to support a provisional, fixed, and immediately loaded full-arch prosthesis. Combining tilted and straight implants for supporting fixed prostheses can be considered a viable treatment modality resulting in a more simple and less time consuming procedure, in significantly less morbidity, in decreased financial costs and a more comfortable postsurgical period for the patients. The authors present a case report with mandibular atrophy and left mental foramina on the top of the residual crest.
application/pdf
1971-1441
107
4
en
G. Sammartino 
https://creativecommons.org/licenses/by-nc-nd/4.0
Annali di stomatologia
implant placement
Safe approach in “All-on-four” technique: a case report
Text.Serial.Journal
https://www.annalidistomatologia.eu/ads
5
Case Report
2022-08-12
2022-08-12
2014-12-01
2023-12-04
142-145
Ann Stomatol (Roma)
G. Sammartino 
2014
10.59987/ads/2014.4.142-145
142
1971-1441
4
implant placement
en
145
Safe approach in “All-on-four” technique: a case report
https://www.annalidistomatologia.eu/ads/article/download/107/92
5
                                                                                                             Case report



    Safe approach in “All-on-four” technique:
    a case report




                                                                                                           i
                                                                                                         al
                                                                                                      on
    Marouene Ben Hadj Hassine, DDS1                              authors state that the long-term performance of short
    Paolo Bucci, MD, DDS2                                        implants is less understood, especially in the posteri-
    Roberta Gasparro, DDS, PhD2                                  or maxilla with lower bone density (6). Vertical aug-
    Alessandro Espedito Di Lauro, DDS2                           mentation procedures increase patient morbidity and
    Gilberto Sammartino, MD, DDS                                 the outcome is less predictable, mainly in the posteri-




                                                                                            zi
                                                                 or mandible. Cantilever prostheses might incur higher
                                                                 rates of prosthetic complications such as abutment
    1 Department of Oral Medicine and Oral Surgery, Uni-         loosening, denture fracture and implant failure.




                                                                              na
      versity of Dental Medicine, Monastir, Tunisia              Due to the less predictable long-term prognosis asso-
    2 University of Naples Federico II, Italy                    ciated with the above mentioned procedures, the “All-
                                                                 on-Four” technique was proposed for the rehabilita-
                                                                 tion in edentulous jaws. The“All-on-Four” concept is




                                                                   er
    Corresponding author:                                        based on the placement off our implants (two axial
    Gilberto Sammartino, MD, DDS                                 and two tilted implants) in the anterior part of fully
    Federico II University                                       edentulous jaws to support a provisional, fixed, and
    Via Pausini, 5                                               immediately loaded full-arch prosthesis.
    80131 Napoli, Italy


                                                           t     Combining tilted and straight implants for supporting
    E-mail: gilberto.sammartino@unima.it
                                                        In       fixed prostheses can be considered a viable treat-
                                                                 ment modality (7) resulting in a more simple and less
                                                                 time consuming procedure, in significantly less mor-
    Summary                                                      bidity, in decreased financial costs and a more com-
                                                                 fortable postsurgical period for the patients (8).
                                           ni
    The “All-on-Four” concept is based on the place-
    ment of four implants in the anterior part of fully
    edentulous jaws to support a provisional, fixed,             Case presentation
                                  io

    and immediately loaded full-arch prosthesis.
    Combining tilted and straight implants for sup-              A 58-year-old man, edentulous for a long period of
    porting fixed prostheses can be considered a vi-             time due to periodontal disease, was referred to the
    able treatment modality resulting in a more sim-             Department of Oral Surgery-University of Naples
                         iz



    ple and less time consuming procedure, in signifi-           Federico II, Italy, requiring a fixed prosthetic rehabili-
    cantly less morbidity, in decreased financial costs          tation in the lower jaw. His past medical history was
    and a more comfortable postsurgical period for               uneventful (Fig. 1).
          Ed




    the patients. The authors present a case report              The panoramic radiograph revealed an advanced
    with mandibular atrophy and left mental foramina             alveolar bone resorption, particularly in the mandible
    on the top of the residual crest.                            (Fig. 2). The Ct scan confirmed the mandibular atro-
                                                                 phy and showed the left mental foramina on the top
    Key words: edentulous jaw, dental implants, im-              of the residual crest (Fig. 3).
    plant placement.                                             The “All-on-Four” technique was scheduled to reha-
IC




                                                                 bilitate the lower jaw.
                                                                 Under local anesthesia, a full thickness crestal inci-
    Introduction                                                 sion was performed from the right first molar region to
                                                                 the left first premolar one. A midline releasing incision
C




    Current standards in implant dentistry are intended to       was carried out to facilitate flap reflection and to iden-
    provide prosthetic restorations with the finest esthetic     tify the left mental nerve emergence (Fig. 4). The 2
    and functional outcomes. Several parameters have been        mm osteotomy was made in the midline position and
    suggested to achieve gold standard results: adequate         the guide was placed (Fig. 5). The vertical lines on
©




    bone height, width and sagittal projection, adequate soft    the guide were used as a reference to prepare the
    tissue quantity and quality, preservation of buccal sulcus   implant sites in the correct position, with an angula-
    and adequate papillae and gingival contour (1) .             tion which should not exceed 45°. All sites were pre-
    Solutions to inadequate ridge height include the use         pared using the manufacturer’s guidelines (Tekka In-
    of short implants (2) , vertical ridge augmentation pro-     kone®), under copious sterile saline irrigation. A con-
    cedures (3, 4), or cantilever prostheses (5). Although       trol of a possible communication between implant
    having a comparable short-term survival rate, some           sites was done before implant placement.

    142                                                                            Annali di Stomatologia 2014; V (4): 142-145
    Safe approach in “All-on-four” technique: a case report


    The two anterior implants (Tekka In-kone®) were placed           out accidental displacement, when an alginate im-
    in the incisive area, whereas the two posterior implants         pression was taken.
    were placed, following the diagonal of the rectangle (Fig.       The polyvinylsiloxane impression of the complete re-
    6), at an angle of 30° mesially to the mental foramina.          movable prosthesis was made to detect the position
    After soft tissue management and closure, straight               of implants and soft tissue.




                                                                                                                 i
    and angulated abutments were placed onto the im-                 The definitive, immediate loaded prosthesis was giv-




                                                                                                               al
    plants (Fig. 7) and the multiunit impression copings             en to the patient after 24 hours (Fig. 9).
    were attached to the prosthetic abutments and splint-            The panoramic radiograph at 1-year-follow up re-
    ed using wire-bars and low shrinkage autopolymeriz-              vealed a good bone healing and no sign of bone re-




                                                                                                            on
    ing resin (Fig. 8) to ensure an accurate transfer with-          sorption around implant shoulders (Fig. 10).




                                                                                                   zi
                                                                                    na
                                                                    t   er
    Figure 1. Preoperative clinical view.
                                                                 In  Figure 2. Preoperative panoramic radiograph.
                                                  ni
                                     io
                           iz
           Ed




    Figure 3. CT Scan showing the crestal position of the left mental nerve.
IC
C
©




    Figure 4. Identification of the mental nerve: (left side).       Figure 5. Identification of the mental nerve: (right side).


    Annali di Stomatologia 2014; V (4): 142-145                                                                                    143
    M.B. Hadj Hassine et al.




                                                                                                          i
                                                                                                        al
                                                                                                     on
                                                               Figure 10. Panoramic radiograph after 1-year-follow-up.




                                                                                           zi
    Figure 6. Placement of the mandibular guide.
                                                               Discussion




                                                                             na
                                                               A recent shift in practice paradigm has been to minimize
                                                               treatment costs and patient morbidity while providing the
                                                               most satisfying patient-centered treatment outcomes ac-
                                                               cording to the state of the art of dental practice. The “All-




                                                                 er
                                                               on-Four” treatment concept is an attempt to reach these
                                                               objectives by providing relatively straight forward, pre-
                                                               dictable treatment option to rehabilitate edentulous pa-
                                                               tients with a high outcome of quality of life (9).



                                                           t   In this technique, the placement of the two posterior
                                                        In     implants in front of mental foramina and tilted with a
                                                               distal direction avoids to injure the inferior alveolar
                                                               nerve and decreases the cantilevers, allowing the in-
                                                               crease of the polygonal area for a full fixed prosthesis
    Figure 7. Preparation of the distal implant site.          and providing satisfactory molar support (10, 11). Ac-
                                               ni
                                                               cording to Krekmanov et al., the gained mean dis-
                                                               tance of prosthesis support in the mandible is 6,5 mm
                                                               while it is 9,3 mm in the maxilla (12). The “All-on-
                                    io

                                                               Four” procedure also improves cortical anchorage
                                                               and primary stability, allowing the use of longer im-
                                                               plants. In a three-dimensional finite element analysis
                                                               about load transmission using different implant incli-
                           iz



                                                               nations and cantilever lengths, Bevilacqua et al. re-
                                                               ported a reduction of stress around anterior implants
                                                               in a full fixed prosthesis design, when tilted implants
          Ed




                                                               were compared to straight implants (13).
                                                               Furthermore there are no significant differences be-
                                                               tween axial and tilted implants in terms of success
                                                               rates and marginal bone loss (14).
                                                               In the present case report, the crestal position of the
    Figure 8. Placement of straight and angulated abutments.   mental nerve requested to change the flap design
IC




                                                               with respect to the surgical protocol, which consists
                                                               of a linear incision performed from the first molar to
                                                               the contralateral one, with or without two vertical dis-
                                                               tal incisions. The midline releasing incision allowed
C




                                                               an easier reflection of the flap, a less difficult implant
                                                               placement and nerve injury preservation.
                                                               The bone growth around the implant shoulders might
                                                               be justified by the subcrestal position and the implant
©




                                                               characteristics, such as platform switching and a
                                                               morse taper connection. Moreover, the microstruc-
                                                               tured surface texture extended onto the implant
                                                               shoulder seems to play a role in minimizing the mar-
                                                               ginal bone loss (0.11 mm, 0.08 mm) and in promoting
                                                               bone formation on the implant platform, even when
    Figure 9. The definitive prosthesis.                       using tilted implants (15, 16).

    144                                                                           Annali di Stomatologia 2014; V (4): 142-145
    Safe approach in “All-on-four” technique: a case report


    Conclusion                                                                   plications following augmentation with cancellous block al-
                                                                                 lografts. J Periodontol. 2010;81:1759.
    The “All-on-4” treatment concept seems to be an al-                     6.   Hashemi HM. Neurosensory function following mandibular
                                                                                 nerve lateralization for placement of implants. Int J Oral Max-
    ternative option for rehabilitating edentulous jaws
                                                                                 illofac Surg. 2010; 39:452.
    compared with advanced surgical approaches without




                                                                                                                            i
                                                                            7.   Vega LG, Bilbao A. Alveolar distraction osteogenesis for den-
    using removable prostheses. It is a cost-effective pro-




                                                                                                                          al
                                                                                 tal implant preparation: An update. Oral Maxillofac Surg Clin
    cedure, decreasing the treatment times, the morbidity                        North Am. 2010;22:369.
    and allowing a higher patient quality of life.                          8.   Peñarrocha Diago M, Maestre Ferrín L, Peñarrocha Oltra D,
    Marginal bone loss around splinted tilted implants to                        Canullo L, Calvo Guirado JL, Peñarrocha Diago M. Tilted im-




                                                                                                                       on
    support full-arch fixed prosthesis doesn’t significantly                     plants for the restoration of posterior mandibles with horizontal
    differ from straight implants in short and medium-                           atrophy. An alternative treatment. J oral Maxillofac Surg.
    term. Nevertheless, long-term results are required to                        2013;71.856-864.
    verify this finding. Furthermore, platform switching,                   9.   Rangert B, Jemt T, Jörneus L. Forces and moments on Bråne-
                                                                                 mark implants. Int J Oral Maxillofac Implants. 1989;4:241-247.
    morse taper connection and microstructured surface




                                                                                                            zi
                                                                           10.   Sertgöz A, Güvener S. Finite element analysis of the effect
    texture extended onto the implant shoulder seem to
                                                                                 of cantilever and implant length on stress distribution in an
    play a role in stabilizing the peri-implant bone, also                       implant-supported fixed prosthesis. J Prosthet Dent.
    when tilted implants are used.




                                                                                           na
                                                                                 1996;76:165-169.
                                                                           11.   Butura CC, Galindo DF, Jensen OT. Mandibular all-on-four
                                                                                 therapy using angled implants: a three-year clinical study of
    References                                                                   857 implants in 219 jaws. Oral Maxillofac Surg Clin North Am.
                                                                                 2011 May;23(2):289-300.




                                                                             er
     1. Guerrero C, Lopez P, Figueroa F, et al. Three-dimensional          12.   Malo P, Rangert B, Nobre M. ‘‘All-on-four’’ immediate-func-
        alveolar distraction osteogenesis. In: Bell W, Guerrero C, ed-           tion concept with Branemark system implants for completely
        itors. Distraction osteogenesis of the facial skeleton. 1st edi-         edentulous mandible: A retrospective clinical study. Clin Im-
        tion. Hamilton (Canada): BC Decker, 2007; 457-93.                        plant Dent Relat Res. 2003;5:2.
                                                                           13.   De Vico G, Bonino M, Spinelli D, Schiavetti R, Sannino G,



                                                                    t
     2. Esposito M, Grusovin MG, Coulthard P, Worthington HV. The
        efficacy of various bone augmentation procedures for den-                Pozzi A, Ottria L. Rationale for tilted implants: FEA consid-
        tal implants. A Cochrane systematic review of randomized
                                                                 In              erations and clinical reports. Oral Implantol (Rome). 2011
        controlled clinical trials. Int J oral Maxillofac Implants.              Jul;4(3-4):23-33.
        2006;21:696-710.                                                   14.   Krekmanov L, Kahn M, Rangert B, Lindstrom H. Tilting of pos-
     3. Sorní M, Guarinós J, García O, Peñarrocha M. Implant re-                 terior mandibular and maxillary implants of improved pros-
        habilitation of the atrophic upper jaw: a review of the litera-          thesis support. Int J Oral Maxillofac Implants. 2000;15:405-
                                                  ni
        ture since 1999. Med Oral Patol Oral Cir Bucal. 2005;10 Sup-             414.
        pl 1:E45-56.                                                       15.   Bevilacqua M, Tealdo T, Pera F, et al. Three-dimensional fi-
     4. Maestre-Ferrín L, Boronat-Lopez A, Penarrocha-Diago M,                   nite element analysis of load transmission using different im-
        et al. Augmentation procedures for deficient edentulous ridges,          plant inclinations and cantilever lengths. Int J Prosthodont.
                                       io


        using on lay autologous grafts: An update. Med Oral Patol                2008; 21:539-542.
        Oral Cir Bucal. 2009;14:402.                                       16.   Gowgiel JM. The position and course of the mandibular canal.
     5. Chaushu G, Mardinger O, Peleg M, et al. Analysis of com-                 J Oral Implantol. 1992;18:383.
                            iz
           Ed
IC
C
©




    Annali di Stomatologia 2014; V (4): 142-145                                                                                              145
