Bone Grafting challenges
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Dental implants require that the patient have sufficient bone to provide anchorage for primary stability. Long-term evidence has shown that bone quality and quantity directly impacts the outcome of dental implant treatment both in the short- and long-term. Even among healthy patients, the maxilla is already one of the least dense areas of bone in the oral cavity.[1] Following tooth loss or extraction, bone remodelling occurs, reducing the mass of bone in the region and altering its structural and mechanical qualities. On average, healed sockets lose 2.6-4.5 mm in width and 0.4-3.9 mm in height during the immediate post-extraction period. In the molar and premolar region, up to half of this ridge width reduction occurs within the first year. The process is heavily front loaded, with around two-thirds of the dimensional changes occurring in the first three months following extraction.[2]
The sinus lift technique is now commonly used in posterior maxilla when subantral bone is not substantial enough for implant use. Most often a lateral window approach is indicated, however, anatomical variations such as particularly thick buccal bone or a deep palatonasal recess can make this particularly challenging. When using the lateral window approach several reviews have reported that long-term implant survival appears to be improved through the use of a resorbable barrier membrane to cover the access window.4
The most frequently occurring intraoperative complication during sinus augmentation, as reported in the literature, is perforation or laceration of the sinus lining.[3],[4] The presence of anatomical features like Underwood’s septa and the specific morphology of the sinus lining, can increase the difficulty in avoiding its perforation. Such features should be detected and considered during pre-surgical planning in order to avoid complications during surgery, but they are not a contraindication to treatment.[5] The thickness of the lining is often asymmetrical – thicker on one side of the head than the other. Though only weakly osteogenic itself, the lining helps supply blood to the graft material.[6] Where sinus lining perforation does occur, it appears to raise the risk of intraoperative and post-operative complications, and may increase the risk of implant failure. Repairing the membrane reduces the risk of these complications.[7],[8]
There are relatively few contraindications for sinus grafting. These include: active sinus infection or pathology, recurrent chronic sinusitis, recurrent fungal sinusitis, uncontrolled/poorly controlled diabetes, cystic fibrosis, maxillary sinus hypoplasia, neoplasms, previous or ongoing radiation therapy at the site, and ongoing drug abuse. Medical conditions and medications that contraindicate implant placement are also contraindications for sinus augmentation.[9]
Chronic sinusitis is a relative rather than absolute contraindication. One possible repercussion of chronic sinusitis is that it can thicken the sinus lining substantially (as can other sources of chronic inflammation), potentially raising the risk of complications. A significant minority of sinus graft patients have some history of sinus pathology, at around 40%.[10] This is unsurprising given that the close proximity of the tooth roots (particularly those in the maxillary posterior) and the sinus floor allows infection to spread from one to the other with relative ease. Patients with endodontic infections and periodontal disease are around three and half times more likely to have chronic sinusitis.[11] Where sinusitis is or has been present, it is important to carefully evaluate the pathologic condition of the sinus. For example, it may be a sign of a maxillary cyst, tumour, lesions, active infection, or a root having penetrated the sinus. These should be prioritised and resolved before sinus grafting is attempted.[12] Certain incidental findings (IFs) that are discovered during assessment may warrant urgent ENT referral or at least an ENT opinion, such as fungal infections or potentially neoplastic lesions.
One of the main disadvantages of lateral sinus grafting, in grossly pneumatised sinuses, is that the implant placement must be deferred by 4-8 months to allow bone graft consolidation before implants can be placed. This increases the overall duration of treatment time.
For patients who are not suited to bone grafting there are alternatives, such as use of shorter implants or zygomatic implants. Zygomatic procedures use much longer implants that are inserted into the zygoma bone, providing strong anchorage and bypassing the need to augment the maxillary sinuses or the alveolar bone. This can create structural anchorage in cases where bone loss is extensive (e.g. oncology patients), or where full arch implants or previous bone grafting has either already failed or is anticipated to fail if attempted. When quad zygomatic implants are used immediate loading (same day teeth) becomes a really attractive treatment option in comparison to conventional grafted solutions that usually take several months to complete.
If you are dealing with complex cases such as these, consider referring your patient to the Centre for Oral Maxillofacial and Dental Implant Reconstruction, a ZAGA centre based in Manchester. Led by Professor Cemal Ucer – Specialist Oral Surgeon – the practice offers the latest treatments and technologies to ensure the highest standard of clinical care in even the most challenging situations. The team are well-versed in complex procedures, including nerve lateralisation and repositioning, hard and soft tissue and sinus graftig, and zygomatic dental implants – allowing us to find the right solution for your patient’s specific needs.
The quality and quantity of bone present in the posterior maxilla makes the region more difficult to treat with dental implants than in other areas of the jaw. This can be further complicated by case history and anatomical variations. However, thanks to the development of multiple techniques, there are vanishingly few absolute contraindications and the majority of patients can safely receive dental implants. Both sinus grafting and zygomatic procedures have high success rates (>95%) when planned and performed with care and precision using evidence-based treatment concepts such as the ZAGA-Straumann Zygomatic implants.4,[13],[14] The anatomically guided ZAGA Zygomatic Implant protocol created Dr Aparicio is aimed at preserving maximum amount of bone whilst preserving the integrity and seal of the maxillary sinus to avoid long term sinus complications.
Centre for Oral and Maxillofacial & Dental Implant Reconstruction and ZAGA Centre
ICE Hospital, Manchester UK
For referrals or training opportunities in maxillary sinus grafting and or ZAGA Zygomatic Implant techniques, please contact Professor Ucer at cemal.ucer@icedental.institute or Mel Hay at mel@mdic.co
01612 371842
www.ucer-clinic.dental
[1] Balaji S. Direct v/s indirect sinus lift in maxillary dental implants. Annals of Maxillofacial Surgery. 2013; 3(2): 148-153. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3814663/ June 2, 2021.
[2] Chappuis V., Araújo M., Buser D. Clinical relevance of dimensional bone and soft tissue alterations post-extraction in esthetic sites. Periodontology 2000. 2017; 73(1): 73-83. https://doi.org/10.1111/prd.12167 June 2, 2021.
[3] Ting M., Rice J., Braid S., Lee C., Suzuki J. Maxillary sinus augmentation for dental implant rehabilitation of the edentulous ridge: a comprehensive overview of systematic reviews. Implant Dentistry. 2017; 26(3): 438-464. https://journals.lww.com/implantdent/fulltext/2017/06000/Maxillary_Sinus_Augmentation_for_Dental_Implant.19.aspx June 3, 2021.
[4] Meleo D., Mangione F., Corbi S., Pacifici L. Management of the Schneiderian membrane perforation during the maxillary sinus elevation procedure: a case report. Annali di Stomatologia. 2012; 3(1): 24-30. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3392662/ June 3, 2021.
[5] Malec M., Smektała T., Trybek G., Sporniak-Tutak K. Maxillary sinus septa: prevalence, morphology, diagnostics and implantology implications. Systematic review. Folia Morphologica. 2013; 73(3): 259-266. http://dx.doi.org/10.5603/FM.2014.0041 June 3, 2021.
[6] Barbu H., Iancu S., Mirea I., Mignogna M., Samet N., Calva-Guirado J. Management of Schneiderian membrane perforations during sinus augmentation procedures: a preliminary comparison of two different approaches. Journal of Clinical Medicine. 2019; 8(9): 1491. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6780245/ June 3, 2021.
[7] Park W., Han J., Kang P., Momen-Heravi F. The clinical and radiographic outcomes of Schneiderian membrane perforation without repair in sinus elevation surgery. Clinical Implant Dentistry and Related Research. 2019; 21(5): 931-937. https://doi.org/10.1111/cid.12752 June 3, 2021.
[8] Al-Moraissi E., Elsharawy A., Abotaleb B., Alkebsi K., Al-Motwakel H. Does intraoperative perforation of Schneiderian membrane during sinus lift surgery cause an increased the risk of implant failure? A systematic review and meta regression analysis. Clinical Implant Dentistry and Related Research. 2018; 20(5): 882-889. https://doi.org/10.1111/cid.12660 June 3, 2021.
[9] Khehra A., Levin L. Maxillary sinus augmentation procedures: a narrative clinical review. Quintessence International. 2020; 51(7): 578-584. http://www.quintpub.com/userhome/qi/qi_51_7_khehra_p578.pdf June 3, 2021.
[10] Insua A., Monje A., Chan H. Wang H. Association of inflammatory status and maxillary sinus Schneiderian membrane thickness. Clinical Oral Investigations. 2018; 22: 245-254. https://doi.org/10.1007/s00784-017-2105-3 June 3, 2021.
[11] De Lima C., Devito K., Vasconcelos L., do Prado M., Campos C. Correlation between endodontic infection and periodontal disease and their association with chronic sinusitis: a clinical-tomographic study. Journal of Endodontics. 2017; 43(12): 1978-1983. https://doi.org/10.1016/j.joen.2017.08.014 June 3, 2021.
[12] Kim J., Jang H. A review of complications of maxillary sinus augmentation and available treatment methods. Journal of the Korean Association of Oral and Maxillofacial Surgeons. 2019; 45(4): 220-224. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6728618/ June 3, 2021.
[13] Bortoluzzi M., Manfro R., Fabris V., Cecconello R., Derech E. Comparative study of immediately inserted dental implants in sinus lift: 24 months of follow-up. Annals of Maxillofacial Surgery. 2014; 4(1): 30-33. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4073458/ June 3, 2021.
[14] Ramezanzade S., Yates J., Tuminelli F., Keyhan S., Yousefi P., Lopez-Lopez J. Zygomatic implants placed in atrophic maxilla: an overview of current systematic reviews and meta-analysis. Maxillofacial Plastic and Reconstructive Surgery. 2021; 43: 1. https://doi.org/10.1186/s40902-020-00286-z June 3, 2021.
