Journal of Dental Implants

ORIGINAL ARTICLE
Year
: 2014  |  Volume : 4  |  Issue : 1  |  Page : 44--47

From maxilla to zygoma: A review on zygomatic implants


DR Prithviraj, Richa Vashisht, Harleen Kaur Bhalla 
 Department of Prosthodontics, Government Dental College and Research Institute, Victoria Hospital Campus, Fort, Bengaluru, Karnataka, India

Correspondence Address:
Richa Vashisht
Government Dental College and Research Institute, Victoria Hospital Campus, Fort, Bengaluru - 560 002, Karnataka
India

Abstract

Purpose: Patients with moderate to severe atrophy challenge the surgeon to discover alternative ways to use existing bone or resort to augmenting the patient with autogenous or alloplastic bone materials. The objective of the following study was to review the published literature to evaluate treatment success with zygomatic implants in patients with atrophic posterior maxilla. Study Selection: Medline/PubMed searches were conducted using the terms atrophic maxilla, zygomatic implant, zygomatic bone, grafts, maxillary sinus, as well as combinations of these and related terms. The few articles judged to be relevant were reviewed. Results: Based on the current literature review, zygomatic implants show excellent survival rates (>90%) and a low incidence of complications. Conclusion: With proper case selection, correct indication and knowledge of the surgical technique, the use of zygomatic implants associated with standard implants offers advantages in the rehabilitation of severely resorbed maxillae, especially in areas with inadequate bone quality and volume, without needing an additional bone grafting surgery, wherefore shortening or avoiding hospital stay and reducing surgical morbidity.



How to cite this article:
Prithviraj D R, Vashisht R, Bhalla HK. From maxilla to zygoma: A review on zygomatic implants.J Dent Implant 2014;4:44-47


How to cite this URL:
Prithviraj D R, Vashisht R, Bhalla HK. From maxilla to zygoma: A review on zygomatic implants. J Dent Implant [serial online] 2014 [cited 2020 Sep 18 ];4:44-47
Available from: http://www.jdionline.org/text.asp?2014/4/1/44/130973


Full Text

 Introduction



Dental implants are now commonly used for replacing missing teeth in various clinical situations. Dental implants are surgically inserted in the jawbones. Unfortunately, restrictions have appeared in the use of oral implants. One of them is the lack of sufficient bone volume, especially in the posterior maxilla. [1]

During the last three decades, several surgical procedures have been developed to increase local bone volume in deficient anatomical regions, including total/segmental bone on lays, Le Forte1 osteotomy with interpositional bone grafts and grafting of the maxillary sinus with autogenous bone and/or bone substitute. [2]

These techniques pose a series of inconveniences, such as the need for multiple surgical interventions, the use of extraoral bone donor sites (e.g., iliac crest or skull) - with the morbidity involved in surgery of these zones - and the long duration during which patients remain without rehabilitation during the graft consolidation and healing interval. These factors complicate patient acceptance of the restorative treatment and limit the number of procedures carried out.

In order to overcome such limitations, different therapeutic alternatives have been proposed, such as, implants placed in specific anatomical areas like the pterygoid region, the tuber or the zygoma [Figure 1]. Any of these procedures requires considerable surgical expertise and has its own advantages, limits, surgical risks and complications involving biological and financial costs. The placement of implants in the zygomatic bone as an alternative to maxillary reconstruction with autogenous bone grafts has been considered a viable option in the rehabilitation of atrophic maxillae.{Figure 1}

Anatomy of Zygomatic Bone

The zygoma bone can be compared to a pyramid, offering an interesting anatomy for the insertion of implants. In an article in 1993, Aparicio et al. mentioned the possibility of inserting dental implants in the zygomatic bone. [3] In 1997, Weischer et al. cited the use of the zygoma as a support structure in the rehabilitation of patients subjected to maxillectomies. [4] Following Branemark's description, Uchida et al. in 2001, measured the maxilla and zygoma in 12 cadavers, observing that the apex of a 3.75 mm- diameter implant requires a zygoma of at least 5.75 mm in thickness. With respect to implant placement, they advised that an angulation of 43.8° or less increases the risk of perforating the infratemporal fossa or the lateral area of the maxilla; if the angulation is more vertical, 50.6° or more, this increases the risk of perforating the orbital floor. [5]

Nkenke et al. in their study used computed tomography and histomorphometry to examine 30 human zygoma, the study revealed that the zygomatic bone consists of trabecular bone, an unfavorable parameter for implant placement; however, the success of implants placed in the zygomatic bone was achieved by the implant crossing four portions of cortical bone. [6]

In a study done by Kato et al. investigated the internal structure of the edentulous zygomatic bone in cadavers using micro-computed tomography, finding that the presence of wider and thicker trabeculae at the apical end of the fixture promotes initial fixation. [7]

 Description of The Zygomatic Implant



The zygomatic implants are self-tapping screws in c.p. titanium with a well-defined machined surface. They are available in eight different lengths ranging from 30 to 52.5 mm. They present a unique 45° angulated head to compensate for the angulation between the zygoma and the maxilla [Figure 2]. The portion that engages the zygoma has a diameter of 4.0 mm and the portion that engages the residual maxillary alveolar process a diameter of 4.5 mm. [8],[9]{Figure 2}

 Presurgical Evaluation



Clinical examination is not sufficient for this evaluation and radiologic assessment has to be considered. Bedrossian et al. in their study on zygomatic and premaxillary implants used panoramic radiographs, which generally depict the size and configuration of the maxillary sinuses, the height of the residual ridge and the position of the nasal floor. The body of the zygoma can usually be visualized. [9] However, orthopantomography can give distorted information and therefore, the examination of choice is the spiral or helicoid computed tomography (CT) scan, which makes two- and three-dimensional imaging possible with axial cuts every 2 mm parallel to the palatal arch and conventional tomography with frontal tomograms perpendicular to the hard palate every 3-4 mm. The CT scan also gives the opportunity to visualize the health of the maxilla and the sinus. Sinusitis, polyps or any sinusal pathology can be excluded. The density, length and volume of the zygoma can be evaluated and special templates for inserting the zygomatic implants can be constructed on stereolithographic models to facilitate the orientation of the zygomatic implants during the surgery with minimal errors in angulation and position. [10] Vrielinck et al., presented a planning system for zygomatic implant insertion based on the pre-operative CT imaging; they calculated the position of the implants and fabricated a surgical guide. Using this system they obtained a success rate of 92% in 29 patients with zygomatic implants (two implants did not reach the zygomatic arch when using this surgical guide). [11]

 Surgical Procedure



The original procedure, defined by Branemark in 1998, consisted of the insertion of a 35-55 mm-long implant anchored in the zygomatic bone following an intra-sinusal trajectory. [12] Since this description, many authors have varied the technique slightly. Stella and Wagner described a variant of the technique (Sinus Slot Technique) in which the implant is positioned through the sinus via a narrow slot, following the contour of the malar bone and introducing the implant in the zygomatic process. In this way, the need for fenestration of the maxillary sinus is avoided and the implant is caused to emerge over the alveolar crest at first molar level, with a more vertical angulation [Figure 3]. [13] Peñarrocha et al. 12 published in 2007 a series of 21 cases with the "Slot technique" with a 100% survival rate, but the Schneiderian membrane was perforated in all cases, even though the incidence of sinus pathology was low (two cases). [14]{Figure 3}

 Multiple Zygomatic Implants



The use of multiple zygomatic implants (i.e., two to three in each side) was suggested by Bothur et al. [15] In a recent study, Duarte et al. used four zygomatic implants and no premaxillary conventional implants in the prosthetic rehabilitation of 12 patients with edentulous and severely resorbed maxillas. A fixed bridge of a gold framework and acrylic teeth was fabricated and delivered shortly after implant surgery. The patients were evaluated after 6 and 30 months when the bridges were removed for individual testing of implant stability. One zygomatic implant was found to be loose at the 6-month follow-up and another one was found to be loose at the 30-month check-up. Thus, the overall survival rate was 95.8% after 30 months of follow-up. No severe complications relating to the sinus or the soft-tissues were reported. [16]

 Complications



The reported complications associated with zygomatic implants include postoperative sinusitis, oroantral fistula formation, periorbital and subconjunctival hematoma or edema, lip lacerations, pain, facial edema, temporary paresthesia, epistaxis, gingival inflammation and orbital penetration/injury [Table 1]. Post-operative concerns regarding difficulty with speech articulation and hygiene caused by the palatal emergence of the zygomatic implant and its effect on the prosthesis suprastructure have been reported.{Table 1}

 Conclusion



The zygomatic implant is an alternative procedure to bone augmentation, maxillary sinus lift and to bone grafts in patients with posterior atrophic maxillae. The zygomatic implant technique should be regarded as a major surgical procedure and proper training is of course needed. However, in comparison with bone grafting procedures, the technique is less invasive and complicated and has a lower risk of morbidity due to the fact that harvesting of bone graft is usually not needed. Based on the current literature review, zygomatic implants show excellent survival rates (>90%) and a low incidence of complications, so this should be considered a valid and safe treatment option when dealing with patients with advanced maxillary atrophy.[25]

References

1Kuabara MR, Ferreira EJ, Gulinelli JL, Paz LG. Rehabilitation with zygomatic implants: A treatment option for the atrophic edentulous maxilla - 9-year follow-up. Quintessence Int 2010;41:9-12.
2Raghoebar GM, Timmenga NM, Reintsema H, Stegenga B, Vissink A. Maxillary bone grafting for insertion of endosseous implants: Results after 12-124 months. Clin Oral Implants Res 2001;12:279-86.
3Aparicio C, Branemark PI, Keller EE, Olive J. Reconstruction of the premaxila with autogenous iliac bone in combination with osseointegrated. Int J Oral Maxillofac Implants 1993;8:61-7.
4Weischer T, Schettler D, Mohr C. Titanium implants in the zygoma as retaining elements after hemimaxillectomy. Int J Oral Maxillofac Implants 1997;12:211-4.
5Uchida Y, Goto M, Katsuki T, Akiyoshi T. Measurement of the maxilla and zygoma as an aid in installing zygomatic implants. J Oral Maxillofac Surg 2001;59:1193-8.
6Nkenke E, Hahn M, Lell M, Wiltfang J, Schultze-Mosgau S, Stech B, et al. Anatomic site evaluation of the zygomatic bone for dental implant placement. Clin Oral Implants Res 2003;14:72-9.
7Kato Y, Kizu Y, Tonogi M, Ide Y, Yamane GY. Internal structure of zygomatic bone related to zygomatic fixture. J Oral Maxillofac Surg 2005;63:1325-9.
8Malevez C, Daelemans P, Adriaenssens P, Durdu F. Use of zygomatic implants to deal with resorbed posterior maxillae. Periodontol 2000 2003;33:82-9.
9Bedrossian E, Stumpel L 3 rd , Beckely ML, Indresano T. The zygomatic implant: Preliminary data on treatment of severely resorbed maxillae. A clinical report. Int J Oral Maxillofac Implants 2002;17:861-5.
10Van Steenberghe D, Malevez C, Van Cleynenbreugel J, Bou Serhal C, Dhoore E, Schutyser F, et al. Accuracy of drilling guides for transfer from three-dimensional CT-based planning to placement of zygoma implants in human cadavers. Clin Oral Implants Res 2003;14:131-6.
11Vrielinck L, Politis C, Schepers S, Pauwels M, Naert I. Image-based planning and clinical validation of zygoma and pterygoid implant placement in patients with severe bone atrophy using customized drill guides. Preliminary results from a prospective clinical follow-up study. Int J Oral Maxillofac Surg 2003;32:7-14.
12Branemark PI. Surgery and fixture installation. Zygomaticus Fixture Clinical Procedures. 1 st ed. Goteborg, Sweden: Nobel Biocare AB; 1998. p. 1.
13Stella JP, Warner MR. Sinus slot technique for simplification and improved orientation of zygomaticus dental implants: A technical note. Int J Oral Maxillofac Implants 2000;15:889-93.
14Peñarrocha M, García B, Martí E, Boronat A. Rehabilitation of severely atrophic maxillae with fixed implant-supported prostheses using zygomatic implants placed using the sinus slot technique: Clinical report on a series of 21 patients. Int J Oral Maxillofac Implants 2007;22:645-50.
15Bothur S, Jonsson G, Sandahl L. Modified technique using multiple zygomatic implants in reconstruction of the atrophic maxilla: A technical note. Int J Oral Maxillofac Implants 2003;18:902-4.
16Duarte LR, Filho HN, Francischone CE, Peredo LG, Brånemark PI. The establishment of a protocol for the total rehabilitation of atrophic maxillae employing four zygomatic fixtures in an immediate loading system - A 30-month clinical and radiographic follow-up. Clin Implant Dent Relat Res 2007;9:186-96.
17Aparicio C, Ouazzani W, Garcia R, Arevalo X, Muela R, Fortes V. A prospective clinical study on titanium implants in the zygomatic arch for prosthetic rehabilitation of the atrophic edentulous maxilla with a follow-up of 6 months to 5 years. Clin Implant Dent Relat Res 2006;8:114-22.
18Bedrossian E, Rangert B, Stumpel L, Indresano T. Immediate function with the zygomatic implant: A graftless solution for the patient with mild to advanced atrophy of the maxilla. Int J Oral Maxillofac Implants 2006;21:937-42.
19Davó R, Malevez C, Rojas J, Rodríguez J, Regolf J. Clinical outcome of 42 patients treated with 81 immediately loaded zygomatic implants: A 12- to 42-month retrospective study. Eur J Oral Implantol 2008;1:141-50.
20Pi Urgell J, Revilla Gutiérrez V, Gay Escoda CG. Rehabilitation of atrophic maxilla: A review of 101 zygomatic implants. Med Oral Patol Oral Cir Bucal 2008;13:E363-70.
21Balshi SF, Wolfinger GJ, Balshi TJ. A retrospective analysis of 110 zygomatic implants in a single-stage immediate loading protocol. Int J Oral Maxillofac Implants 2009;24:335-41.
22Aparicio C, Ouazzani W, Aparicio A, Fortes V, Muela R, Pascual A, et al. Immediate/Early loading of zygomatic implants: Clinical experiences after 2 to 5 years of follow-up. Clin Implant Dent Relat Res 2010;12 Suppl 1:e77-82.
23Stiévenart M, Malevez C. Rehabilitation of totally atrophied maxilla by means of four zygomatic implants and fixed prosthesis: A 6-40-month follow-up. Int J Oral Maxillofac Surg 2010;39:358-63
24Migliorança RM, Coppedê A, Dias Rezende RC, de Mayo T. Restoration of the edentulous maxilla using extrasinus zygomatic implants combined with anterior conventional implants: A retrospective study. Int J Oral Maxillofac Implants 2011;26:665-72.
25Davó R, Malevez C, Pons O. Immediately loaded zygomatic implants: A 5-year prospective study. Eur J Oral Implantol 2013;6:39-47.