Journal of Dental Implants
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Table of Contents
Year : 2022  |  Volume : 12  |  Issue : 1  |  Page : 63-68

All-on-four treatment with narrow platform implants in reduced restorative space for moderate atrophic edentulous ridge

Department of Periodontics, Faculty of Dental Science, Institute of Medical Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India

Date of Submission09-Oct-2021
Date of Decision26-Feb-2022
Date of Acceptance27-Feb-2022
Date of Web Publication16-Jun-2022

Correspondence Address:
Dr. Farhan Durrani
Department of Periodontics, Faculty of Dental Science, Institute of Medical Science, Banaras Hindu University, Varanasi, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jdi.jdi_25_21

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The use of dental implants to treat edentulous maxilla and mandible is a well-accepted concept in modern dentistry. However, it is difficult and challenging in atrophic jaws. All-on-four implant concept is an alternative for resorbed jaws, as it obviates extensive bone grafting and waiting time and often provides immediate function. In our article, we describe the use of narrow platform implants (3.3 mm) for a moderate atrophic complete edentulous case with the above concept. The studies with narrow-diameter implants for complete reconstruction are inadequately reported. We followed our case for 3 years after the delivery of final prosthesis.

Keywords: All on four, complete arch prosthesis, full edentulism, narrow-diameter implants, screw-retained implants

How to cite this article:
Durrani F, Pandey A, Singh P, Pandey S, Nahid R. All-on-four treatment with narrow platform implants in reduced restorative space for moderate atrophic edentulous ridge. J Dent Implant 2022;12:63-8

How to cite this URL:
Durrani F, Pandey A, Singh P, Pandey S, Nahid R. All-on-four treatment with narrow platform implants in reduced restorative space for moderate atrophic edentulous ridge. J Dent Implant [serial online] 2022 [cited 2023 May 31];12:63-8. Available from:

   Introduction Top

Complete edentulism is a social stigma. It destroys psychological and emotional well-being along with esteem of an individual. The inability to chew food, speech problems, unesthetic appearance, and reduced oral health are its further consequences. The rehabilitation with a fixed prosthesis may be a challenge as compared to a removable complete denture. Often, a long period of edentulism presents a reduced bone volume of the existing ridges. Augmentation procedures carry complications, surgical risks, high financial costs, and long healing times. There are several therapeutic methods proposed to overcome the above-mentioned disadvantages, such as cantilevered prosthesis, short implants, and tilted and zygomatic implants. Narrow-diameter implants if used carefully can be used in moderate atrophic cases as they have good mechanical properties. The cost of treatment can be reduced as well as the requirements of technical and demanding bone grafting procedures. There is evidence of one-piece implants with immediate and early loading for complete edentulous cases.[1] In our report, we are following the case of a complete fixed implant-retained prosthesis with narrow-diameter implants. The case was completely edentulous with a moderately atrophic ridge which had four implants in each arch with screw-retained complete implant prosthesis. The use of narrow-diameter implants in tilted implant trajectory is rarely reported in the literature, as it is often indicated in low occlusal load positions. Our case is being followed for the last 3 years with a good successful outcome.

   Case Report Top

A 75-year-old lady presented herself with a complete edentulous condition to the faculty of dental sciences with a desire for fixed dentition. There was no significant medical history associated with her except occasional pain killers for joint pains. She underwent total extraction of remaining teeth six weeks earlier [Figure 1]. The patient insisted for a fixed tooth replacement as she was very concerned for aesthetics ,mastication and overall health.
Figure 1: Complete edentulous mouth

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Treatment sequence

A full set of intraoral and extraoral photographs were taken. The presence of pneumatized maxillary sinuses almost till the coronal part of posterior ridges bilaterally complicated the reconstruction [Figure 2]. On computed tomography (64 Slice CT) examination of the maxilla, thin ridges were evident (4/5 mm) [Figure 3]a and [Figure 4]b. In the mandible, the bone was adequate in between the mental foramen but resorption was evident posteriorly on both sides [Figure 4]a and [Figure 4]b. The lips of the patient were thin with no visibility of ridges during full smile [Figure 5]a, [Figure 5]b, [Figure 5]c. The casts of each arch with centric relation were articulated for available space. This was estimated by the tip of central incisor measurement to the existing ridge in the maxilla made through wax-up. It was 11 mm as measured with a calibrated probe. There was no need for bone reduction in the maxilla because the transition line between the prosthesis and ridge was within the confines of upper lip. Ridges had healed as extractions were done 6–8 weeks earlier. The patient was explained about fixed teeth with implant-retained prosthesis, its advantages and advantages and complications involved in its reconstruction. There was denial for bilateral sinus lift and bone augmentation of ridges. The waiting period and huge financial cost were other limitations. A method with just four implants in each arch was explained which may obviate the need of complex procedures which was accepted.
Figure 2: Preoperative orthopantomogram

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Figure 3: (a) Three-dimensional picture of edentulous maxilla. (b) Cross-sectional slices of anterior maxilla

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Figure 4: (a) Three-dimensional picture of edentulous mandible. (b) Cross-sectional slices of anterior mandible

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Figure 5: (a) Half edentulous smile. (b) Lateral view of smile. (c) Full edentulous smile

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Implant surgery


After anesthetizing the edentulous maxilla, full-thickness mucoperiosteal flap was reflected till the posterior molar regions bilaterally. Standardized All-on-4 Guide in the maxilla was stabilized with drilling in the center of the ridge (2 mm) just below the anterior nasal spine [Figure 6]. The drilling started with both tilted posterior implants little palatally on the existing ridges after identifying the anterior wall of the maxillary sinus through radiovisiography. The preparation was made 4 mm anterior to the sinus wall. The sizes of the posterior implants were 3.3 mm/13 mm and anterior were 3.3 mm/10 mm (Rapid Implants; Dentin Implants Technologies Ltd., Israel). The guide helped in tilting the implants posteriorly (30° approximately), drill sequence was initially to the full length (13 mm) with 2 mm twist drill. After that, the implant was self-tapped in the site. Final insertion was done by hand to countersink the head of the implant below the crestal bone (1 mm). The tilting of the posterior implant positioned the implant heads in the second premolar/molar region.
Figure 6: Surgical guide stabilized in maxilla

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Under preparation of the osteotomy in the maxillary cancellous bone helped in achieving good primary stability. Anterior implants were prepared as per guide positions on the ridges with the same principles as described for posterior implants, but the osteotomy was till 10 mm once for each of them with initial drill (2 mm). The positions were lateral incisors regions [Figure 7].
Figure 7: Four implants in anterior maxilla

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After anesthetizing edentulous mandible, full-thickness mucoperiosteal flap was reflected. All-on-4 Guide was positioned after making osteotomy of 8 mm in the midline with 2 mm drill [Figure 8]. The mental foramens were identified bilaterally in the mandible before start of the procedure. The sizes of the posterior implants were 3.3 mm/13 mm and anterior were 3.3 mm/10 mm (Rapid Implants; Dentin Implants Technologies Ltd, Israel). The posterior implants were tilted according to the guide around 30° approximately 3 mm anteriorly from the mental foramens bilaterally. The drill sequence was initially with a 2 mm twist drill to full length of 13 mm. Since the anterior mandible has high cortical content, the next drill was 2.8 mm which went till 13 mm. After that, a 3.2 mm drill was used for half-length (7 mm). Anterior implants osteotomy had the same principle, but the length was 10 mm. All the implants were self-tapped in the osteotomy sites and implant heads in posterior regions were countersunk below the crestal bone [Figure 9].
Figure 8: Surgical guide stabilized in mandible

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Figure 9: Four implants in anterior mandible

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The torque achieved for all the implants was <25 N. Hence, healing abutments were screwed. The patient was kept on antibiotics and analgesics for 7 days. After suture removal, tissues were allowed to heal for 3 weeks. An interim denture was given for the waiting period of 3 months.

Prosthesis fabrication

After 4 months of healing, implants were evaluated for their individual integration. Percussion sounds and radiographic verifications were completed [Figure 10]. Impressions of both arches were taken to record the intermaxillary relationship. Centric records with a retruded position of the mandible were transferred to Semi adjustable articulator (Bio Art A 7 Plus). Teeth settings with midline, smile evaluation, and phonetics were carefully completed. Individualized multiunit abutments (25° with 2 mm collar height for posterior implants, straight for anteriors with same collar height) were tightened on each implant with the assistance of premounted abutment holder. The access holes for the screw were kept occlusally in posterior implants and lingually or palatally with anterior fixtures [Figure 11]. After complete seating and verification, open-tray impression copings were tightened on all the multiunit abutments per arch. These copings were splinted with dental floss and low shrinkage auto polymerizing resin (GC Pattern Resin) [Figure 12]. Definitive prosthesis with earlier recorded intermaxillary relationship guided metal framework fabrication [Figure 13]. Verification was completed in the mouth with passive fit without tension (Sheffield Test). Porcelain veneering on the framework with correct shade as per patient choice was done on both the prostheses [Figure 14]. Guidelines for occlusal load on implants and prosthetic reconstruction depend upon anterior–posterior spread. The cantilever spread in the maxillary prosthesis was kept 6/8 mm because of low bone density and the mandible had 10 mm.[2] Occlusal scheme had a stable relationship in maximum intercuspation. There was freedom for centric movements without interferences in retruded contact positions. They were bilateral on canine and posterior teeth without touching anterior. The cuspal inclines of prosthesis were kept flat and less than the condylar pathway. During lateral movements, it was group function or guidance with flat linear motion. A total of 11 teeth were given in each arch. The screw access holes were closed after final tightening (25N) on each implant in both arches with Teflon tape and composite plug holes [Figure 15]. The patient is on follow-up for the last 3 years [Figure 16], [Figure 17], [Figure 18]. The crestal bone level around implants were evaluated at every visit, especially around posterior abutments. The occlusal scheme pattern and discrepancy if any were corrected. The patient was very pleased with the prosthesis as her social well-being and health improved a lot in these 3 years as per her own observation and experience [Figure 19]a and [Figure 19]b.
Figure 10: Othopantomogram showing eight implants in edentulous ridges

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Figure 11: Multiunit abutments on implants

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Figure 12: Impression procedure of mandibular implants using a custom tray

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Figure 13: Framework fabricated of nickel–chromium

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Figure 14: Maxillary/mandible srew-retained prosthesis

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Figure 15: Prosthesis screwed in the mouth

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Figure 16: Prosthesis screwed in the mouth

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Figure 17: Second-year follow-up orthopantomogram

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Figure 18: Third-year follow-up orthopantomogram

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Figure 19: (a) Smile with prosthesis (Frontal View). (b) Smile with prosthesis (Lateral View)

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   Discussion Top

There is a lot of evidence in literature for narrow-diameter implants and their use in compromised resorbed ridges and can be an alternative for additional surgical procedures.[3],[4],[5] They are often used in posterior regions of the mouth with high load bearing with quite a success. The evidence for use of narrow-diameter implants in edentulous atrophic cases is very rare till date. Tallarico et al. used narrow diameter implants (3.3 mm) for full mouth rehabilitation cases for the first time.[6] However, they did not mention about marginal bone loss and cumulative survival rate in their observation. Maló et al. placed this diameter of implants only in the anterior region of edentulous cases and not in tilted or posterior regions without reporting longevity in treated patients.[7] Klein et al. did a systematic review of a narrow diameter of implants for different clinical conditions compared to standard diameter.[8] The observation was implants with a diameter of 3.3–3.5 mm were well-documented for all indications including load-bearing posterior regions. Piano et al. did a prospective study on immediate loading of a complete fixed prosthesis in maxilla using 4.1/3.3 mm diameter (four implants).[9] After 2 years, there was 100% prosthesis survival with no implant, reconstruction, or abutment failures. Coskunses et al. in their latest study examined the performance of narrow-diameter implants titanium–zirconium implants (Ti-Zr implants [3.3 mm]) (Roxolid®, Institut Straumann® AG, Basel, Switzerland) for full arch immediately loaded prosthesis.[10] In 2-year follow-up and with 179 implants and 28 patients, there were no prosthetic failures, the survival rate was 100%, and implant angulations had no effect on marginal bone loss. Further, it can be observed that Ti-Zr alloy (Roxolid; Switzerland) narrow-diameter implants used in the above-mentioned study had increased biomechanical and biocompatible properties. In our case, we used rapid implants (Dentin Implants; Israel); the micro rings on its neck improved the strength at the crestal area and changes in its thread improved the compression in the bone. SLA (Sandblasted, large grit, acid-etched implant surface) area of bone–implant interface area had favorable load distribution. There was no flattening of the existing ridges at the start of the osteotomies, as the transition line of the prosthesis and gingival margin was not visible during smile of the patient. The marginal bone loss in periodic X-rays was negligible. At every yearly visit, oral hygiene maintenance was enforced and the prosthesis was checked for occlusion discrepancy if any.

   Conclusion Top

Narrow-diameter implants can be used in moderate atrophic edentulous cases. The long implants with angulations are acceptable in posterior load-bearing areas. The removal of bone to accommodate wide-diameter implants can be avoided in selected cases. Our follow-up of 3 years with narrow-diameter implants in the moderate atrophic complete edentulous case had been successful till date.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Gallucci GO, Benic GI, Eckert SE, Papaspyridakos P, Schimmel M, Schrott A, et al. Consensus statements and clinical recommendations for implant loading protocols. Int J Oral Maxillofac Implants 2014;29 Suppl: 287-90.  Back to cited text no. 1
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. 2
Baggi L, Pastore S, Di Girolamo M, Vairo G. Implant-bone load transfer mechanisms in complete-arch prostheses supported by four implants: A three-dimensional finite element approach. J Prosthet Dent 2013;109:9-21.  Back to cited text no. 3
Babbush CA, Kanawati A, Brokloff J. A new approach to the All-on-Four treatment concept using narrow platform NobelActive implants. J Oral Implantol 2013;39:314-25.  Back to cited text no. 4
Krekmanov L, Kahn M, Rangert B, Lindström H. Tilting of posterior mandibular and maxillary implants for improved prosthesis support. Int J Oral Maxillofac Implants 2000;15:405-14.  Back to cited text no. 5
Tallarico M, Meloni SM, Canullo L, Caneva M, Polizzi G. Five-year results of a randomized controlled trial comparing patients rehabilitated with immediately loaded maxillary cross-arch fixed dental prosthesis supported by four or six implants placed using guided surgery. Clin Implant Dent Relat Res 2016;18:965-72.  Back to cited text no. 6
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. 7
Klein MO, Schiegnitz E, Al-Nawas B. Systematic review on success of narrow-diameter dental implants. Int J Oral Maxillofac Implants 2014;29 Suppl: 43-54.  Back to cited text no. 8
Piano S, Romeo E, Sbricoli L, Pisoni G, Cea N, Lops D. Simplified procedure for the immediate loading of a complete fixed prosthesis supported by four implants in the maxillary jaw: A 2-year prospective study. Clin Oral Implants Res 2016;27:e154-60.  Back to cited text no. 9
Coskunses FM, Tak Ö. Clinical performance of narrow-diameter titanium-zirconium implants in immediately loaded fixed full-arch prostheses: A 2-year clinical study. Int J Implant Dent 2021;7:30.  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], [Figure 14], [Figure 15], [Figure 16], [Figure 17], [Figure 18], [Figure 19]


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