Treatment Options for the Posterior Edentulous Jaw

Treatment Options for the Posterior Edentulous Jaw: Surgical Options for Implant Therapy in the Posterior Maxilla of Partially Edentulous Patients

Prof. Dr. Daniel Buser is Professor and Chairman of the Department of Oral Surgery and Stomatology at the School of Dental Medicine, University of Bern. He did research at Harvard, USA from 1989 to 1991, with sabbaticals at the Baylor College of Dentistry, USA (1995), the University of Melbourne, Australia (2007/2008) and Harvard School of Dental Medicine, Boston, USA (2016). His main scientific interests include tissue integration of dental implants, guided bone regeneration including autografts and bone substitutes. He has authored/

Daniel Buser, Alberto Monje, Waldemar Polido

co-authored more than 350 publications. Daniel Buser was ITI President from 2009 to 2013 and has received several awards, among them the the André Schroeder Research Prize (1995) and the Brånemark Osseointegration Award (2013). With over 30 years of surgical experience, he continues to treat more than 150 implant patients per year.

Dr. Alberto Monje started his research career as a clinical postdoc at The University of Michigan in 2011. He then obtained the certificate and Masters in Periodontology from the University of Michigan, Department of Periodontics and Oral Medicine in 2016. He has also received awards and grants for his research and clinical achievements from scientific societies such as the American Academy of Periodontology, the International Team for Implantology and the Osteology Foundation. He is currently the ITI Scholar in the Department of Oral Surgery at the University of Bern, Switzerland, headed by Prof. Daniel Buser, where his research focus is on the long-term outcomes of surgical options for the rehabilitation of the posterior atrophic ridges.

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Forum Implantologicum

TREATMENT OPTIONS FOR THE POSTERIOR EDENTULOUS JAW

ABSTRACT Dr. Waldemar D. Polido is an oral and maxillofacial surgeon with DDS, MS and PhD degrees from PUCRS in Porto Alegre, Brazil, and a residency in OMFS at the University of Texas, Southwestern Medical Center at Dallas, USA. A Fellow and Speaker of the ITI, Dr. Polido was Chair of the ITI Section Brazil from 2007 to 2009 and is the current Education Delegate for the Section until 2018. He is also a member of the ITI Education Committee. Dr. Polido lectures extensively in Brazil and internationally on his main interests: advanced and complex implant surgery and orthognathic surgery. In March 2017 he joined the Indiana University School of Dentistry in Indianapolis, USA, as a Clinical Professor, Director of the Predoctoral Program in Oral and Maxillofacial Surgery and Co-Director of the Center for Implant, Esthetic and Innovative Dentistry.

INTRODUCTION Loss of teeth in the posterior maxilla is a frequent scenario encountered in dentistry. Brugger et al. (2015), analyzing a 3-year patient pool in a surgical specialty clinic, reported that the posterior maxilla accounted for 36 % of the total number of sites treated with dental implants (Brugger et al. 2015). This area has always been considered a challenging region with its unique anatomy of teeth and alveolar bone as well as its proximity and relationship to the maxillary sinus. Early findings in implant dentistry demonstrated significantly lower survival rates in the posterior maxilla, which were correlated with different causes such as poor bone density, complex anatomy and loading protocols with shorter healing periods (Adell et al. 1981, Jaffin & Berman 1991). We must not forget that those were the days where titanium implants with a machined surface were most often used. In addition, longer implants (≥ 15 mm) with bicortical stabilization were recommended (Bahat 1993). Hence, the use of large autogenous bone grafts, mostly from

The rehabilitation of the posterior maxilla with an implant-supported prosthesis is often a demanding treatment for the implant surgeon. The local anatomy can be difficult due to a reduced ridge height in potential implant sites. The present clinically oriented paper discusses the three most often utilized surgical options: (i) the utilization of short implants, (ii) sinus floor elevation (SFE) with the lateral window technique, and (iii) SFE with the transalveolar osteotome technique. A thorough clinical and radiographic examination is required to choose the appropriate surgical approach, which should offer a successful outcome with high predictability and a low risk of complications. In addition, treatment should offer minimal invasiveness and morbidity, when possible. Low morbidity is offered by short 6-mm implants, which are utilized when multiple implants are feasible with splinted implant crowns.

an extraoral donor site, was often recommended (Tolman 1995). The primary objectives of implant therapy continue to be successful treatment outcomes with high predictability concerning long-term function and esthetics and low risk of complications (Buser and Chen 2008). The ultimate goal is long-term success of 30+ years, which means that an inserted and restored implant should have the best prerequisites for successful long-term stability. The secondary objectives of therapy include minimal invasiveness and low morbidity, including the least number of surgical procedures and shorter healing periods. In the past 15 to 20 years of fine tuning in implant dentistry, aspects related to the secondary objectives have substantially improved to make implant therapy more attractive for patients and more patient friendly but without jeopardizing the primary objectives of therapy (Buser et al. 2017). Successful outcomes in implant therapy are influenced by four factors as first outlined by Buser and Chen (Buser and Chen 2008).

A single tooth replacement with 6-mm implants in molar sites is only used in exceptional situations. In all other situations, SFE is required. Both surgical techniques are well documented, but the transalveolar osteotome technique is utilized less frequently, since it requires a ridge height of 5–8 mm and a flat morphology of the sinus floor. Whenever possible, a simultaneous implant placement is performed to avoid a second surgery. For that, sufficient primary stability is important, which can be optimized with tissue level implants. In addition, grafting with a composite graft is preferred, which includes locally harvested autogenous bone chips mixed with a low-substitution bone filler. The various treatment options are discussed and documented with case reports. Keywords: Posterior maxilla, sinus floor elevation, short implants, transalveolar technique, lateral window technique, composite graft

This concept, documented with four interconnected circles, can also be applied to the treatment of the posterior maxilla (Fig. 1). The first and most important circle reflects the implant surgeon, or rather his/her clinical team, since the treatment quality by the surgical and restorative dentist –sometimes provided by the same person – is probably the most crucial factor. Additional members of the clinical team are also the dental technician and – if available – the dental hygienist for the supporting maintenance care program. The talent and expertise of the implant surgeon are decisive for the treatment outcome, as he/she examines the patient to establish his/her risk profile, decides on the most appropriate treatment option, selects the necessary biomaterials, and finally performs the surgical treatment. The crucial importance of this first circle is also documented by the fact that it is larger than the three other circles. The second circle represents the patient with his/her risk factors, indicators and determinants, which include medical, dental and anatomical risk factors together with

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smoking. All these factors must be considered in the selection of the most appropriate treatment option. In the posterior maxilla, the local anatomy is probably the most relevant factor for the selection of the treatment approach. The third circle represents the biomaterials, which include the selected implant and its material, surface, shape, diameter and length, and the implant abutment. In addition, bone grafts, bone substitutes, and barrier membranes are important elements for sinus floor elevation (SFE) procedures. Lastly, the fourth circle to consider is the treatment approach itself for a given clinical situation. In the posterior maxilla with a reduced ridge height and pneumatized sinus cavity, various treatment options are available to achieve the anticipated treatment outcome.

Dental risk factors

Anatomic risk factors

Medical risk factors

Smoking

Education

Short implants

Patient

Transalveolar technique

Skills

Surgical Approach

Implant Surgeon

Experience Implant type

Biomaterials

Barrier Membrane

Lateral window technique Grafting vs. non-grafting

Simultaneous vs. staged approach Xenografts Allografts

Autografts

Fig. 1: The four factors influencing outcomes for the rehabilitation of the posterior maxilla. The circle with the implant surgeon is larger, documenting the crucial importance of the experience and treatment quality provided by the implant surgeon

In accordance with the scope of the Forum Implantologicum, the purpose of this clinical paper is to discuss the surgical options available for implant therapy in

the posterior maxilla in partially edentulous patients. It reflects the authors’ personal long and thoroughly documented experience in the field. In addition, it provides clinical

recommendations for when to use which treatment option to have the best chance of a successful treatment outcome in this challenging clinical scenario.

Fig. 2a: Buccal view of the first quadrant with an extended edentulous space. Tooth #14 is hopeless and needs to be removed. The patient is asking for a fixed dental prosthesis

Fig. 2b: The panoramic view of the CBCT shows a reduced ridge height in area 15 and 16. The Schneiderian membrane is slightly thickened. There is no bone septum visible

Fig. 2c: The occlusal CBCT view shows the sinus pneumatization, a sufficient crest width in all potential implant sites, and a radiolucent interradicular lesion at tooth #17

Fig. 2d: The oro-facial CBCT at tooth #14 shows sufficient crest width of >6 mm for a future implant placement

Fig. 2e: The oro-facial CBCT in area #15 shows sufficient crest width, but a ridge height of less than 4 mm

Fig. 2f: The oro-facial CBCT in area #16 shows sufficient crest width, but a ridge height of only 2.5 mm, requiring a staged SFE procedure

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Forum Implantologicum


ANATOMIC RISK FACTORS IN THE POSTERIOR MAXILLA For surgical treatment planning in the posterior maxilla, a detailed pre-surgical examination of the remaining teeth, the alveolar ridge dimensions and the maxillary sinus play an important role in the decisionmaking process to find the most suitable treatment approach. For this, the utilization of a 3-dimensional (3D) radiographic analysis utilizing a cone beam computerized tomography (CBCT) is recommended nowadays (Jensen & Katsuyama 2011; Bornstein et al. 2015). The detailed clinical and radiographic examination must include several aspects, which are listed in Table 1. A typical case report is shown in Fig 2. In the posterior maxilla, the main anatomical challenge is the ridge height due to the proximity of the maxillary sinus cavity. Nunes et al. reported in a CBCT study that the crest width is most often sufficient for the placement of a standard diameter implant (4 mm) (Nunes et al. 2013). The main problem was the lack of sufficient subantral bone height. The ridge height significantly decreased towards the first and second molar sites. In first molar sites, 88.2% showed a ridge height of