Ultra-Wide-Diameter Implants Gaining Favor for Immediate Placement in Posterior Jaw
André Hattingh, BChD, MChD
André Hattingh, BChD, MChD, runs a specialist implant and periodontal practice in Kent, United Kingdom, and is working toward his PhD at Ghent University. In his lecture at the 2018 Southern Implants International Forum, he presented results from an innovative study co-authored with the University of Pretoria and Southern Implants Research entitled, "Dento-alveolar Measurements and Histomorphometric Parameters of Maxillary and Mandibular First Molars, Using Micro-CT." The study was recently published in Clinical Implant Dentistry and Related Research.1
Immediate placement into fresh ex--traction sockets of multi-rooted teeth is particularly challenging due to the ovoid socket shape and wide dimensions. The presence of interradicular bone also complicates implant positioning, and its absence may hinder primary stability when placing the implant in a single root socket. Furthermore, molar sites frequently lack buccal bone height and width, which makes them highly prone to post-extraction resorption, leading to thread exposure and possibly implant failure.2
Ultra-wide-diameter implants (6 mm to 9 mm diameter) are gaining favor for immediate placement in the posterior jaw because they allow for increased engagement of molar socket walls and provide better stress distribution under the high occlusal loads in the posterior jaw.3,4 The wide platform also simplifies prosthetic design and improves emergence profile by avoiding ridge lapping (Figure 1 and Figure 2).
Dr. Hattingh has performed more than 500 cases of immediate placement using ultra-wide implants, making him a world leader in this technique. He recently published a recommended protocol in the International Journal of Periodontics and Restorative Dentistry.5
Little research has been conducted into establishing common critical dimensions of molar sockets. This research team, therefore, set out to conduct detailed measurements on a sample of mandibular and maxillary first molars in dry skulls using micro-CT in an effort to refine existing classification systems for molar extraction sites and aid implant design and selection. Micro-CT is a high-resolution, non-invasive, non-destructive imaging technique that is currently acknowledged as the gold standard modality for objectively quantifying dental morphology and bone microarchitecture parameters.
Sixty-one first molars from 38 human dried skulls from the Pretoria Bone Collection (22 to 76 years) were scanned on predefined 2-dimensional sections or directly on 3-dimensional models (Figure 3). Tooth morphology was described by four aspects (ie, tooth width, trunk length, root length, and root span), while the socket architecture was assessed by buccal plate thicknesses and bone density measurements. The results of the main parameters measured are presented in Table 1.
It is noteworthy that the buccal plate thickness was found to be less than 1 mm in more than 55% of cases in maxillary first molars, while this was so in only 20.8% of cases in mandibular first molars. A wide range of bone densities was observed, and the comparison between mandible and maxilla did not show a significant difference. Furthermore, cortical densities were negatively correlated with aging, while trabecular densities were not influenced.
Dr. Hattingh concluded his lecture giving thanks to a diverse, multidisciplinary team, including collaborators from the University of Pretoria Department of Anatomy; University of Witwatersrand Human Variation and Identification Research Unit; Ghent University Depart-ment of Periodontology, Oral Implantology, Removable and Implant Prosthetics; Southern Implants Research; the South African Nuclear Energy Corporation; and the Sefako Makgatho Health Sciences University Department of Anatomy and Histology.
References
1. Theye CE, Hattingh A, Cracknell TJ, et al. Dento-alveolar measurements and histomorphometric parameters of maxillary and mandibular first molars, using micro-CT. Clin Implant Dent Relat Res. 2018; doi: 10.1111/cid. 12616. [ePub ahead of print]
2. Fugazzotto PA. Implant placement at the time of maxillary molar extraction: treatment protocols and report of results. J Periodontol. 2008;79(2):216-223.
3. Hsu JT, Fuh LJ, Lin DJ, et al. Bone strain and interfacial sliding analyses of platform switching and implant diameter on an immediately loaded implant: experimental and three-dimensional finite element analyses. J Periodontol. 2009;80(7):1125-1132.
4. Smith RB, Tarnow DP. Classification of molar extraction sites for immediate dental implant placement: technical note. Int J Oral Maxillofac Implants. 2013;28(3):911-916.
5. Hattingh AC, De Bruyn H, Ackermann A, Vandeweghe S. Immediate placement of ultrawide-diameter implants in molar sockets: description of a recommended technique. Int J Periodontics Restorative Dent. 2018;38(1):17-23.
