Robert Felkler presents a case to increase anterior bone volume to support a dental implant using Meisinger Bone Management
Dr Robert Felkler BDS (Lond), MJDF (RCS, Eng), MSc (Dental Implantology)
Principal dentist and implant Surgeon at The Eledent Clinic, Greater London
The presentation of insufficient bone volume in the anterior maxilla is a challenging treatment for dental implant rehabilitation. There are currently a number techniques described within the literature to reconstruct a deficient alveolar ridge in order to facilitate dental implant placement (Esposito et al. 2006). These techniques include the shell technique, titanium reinforced membranes, tenting, bone splitting, mesh, sonic welding, bone block and distraction.
In this case, a titanium lattice combined with a particulate material was selected as both vertical and horizontal gain has been demonstrated to be predictable with a rigid lattice (Troeltzsch et al. 2016). The technique selected for this case utilised a 3D printed titanium lattice produced by Yxoss (CBR, ReOss, Filderstadt, Germany), the design for which is based on the patient’s original pre-operative CBCT scan.
A 37-year-old male patient was referred from another office to reconstruct the upper anterior maxilla for suitable dental implant rehabilitation of the tooth site 21. Clinical examination revealed a significant horizontal and vertical defect, which was confirmed by the CBCT scan. Using the SAC classification from the ITI 2007 consensus, this case was deemed to be complex (Martin et al. 2007). The patient was otherwise a fit and healthy non-smoker with a minimally restored dentition.
A significant lack of facial bone height and width is classified as a three-wall defect (Karn et al. 1984); the combination of a barrier membrane and a grafting material has been demonstrated to provide an increase in vertical gain (Troeltzsch et al. 2016). Additionally, in the author’s opinion, it was deemed that Guided Bone Regeneration (GBR) alone would not suffice and that the shape of the defect would make it difficult to place a block of autogenous bone. Therefore, a rigid titanium barrier was utilised to perform the alveolar bone augmentation with Yxoss Customised Bone Regeneration (CBR)(Seilier et al. 2018). This technique was performed using a combination of a 3D printed titanium lattice, autogenous bone and de-proteinized bovine bone mineral (DBBM) mixture.
As a part of the surgical planning phase, it was crucial to calculate the amount of autogenous bone required for the ideal 50:50 mix, as it may influence the choice of donor site. A simple mathematical equation can help confirm the depth of a particular diameter trephine to harvest sufficient autogenous bone to mix with a xenograft to achieve a 50:50 mix. Alternatively, the ReOss website provides a formula as a reference.
Harvested volume H = V (pi*(D/2)2)
H height V volume D diameter
Using the correct flap design is crucial for such surgeries, and within the literature the mid-crestal incision flap design is well-documented. Alternatively, the ‘Poncho technique’, which has been described for such grafting cases, involves a horizontal incision placed high within the sulcus. However, as there is currently a limited evidence-base available for this technique and hence the mid-crestal incision flap design was selected.
Once profound anaesthesia was achieved, a mid-crestal incision and full thickness flap was raised with distal releasing incisions made distal to both canines. Granulation tissue was removed from the surgical site; the flap was mobilised by releasing the periosteum and advancing the flap. The exposed defect (Fig. 1) can be visualised compared to the 3D planning software’s representation (Fig. 2).
The fit of the titanium lattice was confirmed to be passive, maintained at least 1.5mm from surrounding structures (Fig. 3) and placed according to the 3D planning software’s simulation (Fig. 4). Bleeding holes were created within the defect site to increase blood flow.
Harvesting of the autogenous bone from the ramus was completed using a 6mm Meisinger Trephine (Fig. 5). The harvested bone blocks (Fig. 6) were crushed with a bone mill and a 50:50 mix of autogenous and xenograft (Bio Oss, Geistlich), which were combined with the patient’s blood and placed directly onto the defect (Fig. 7). The titanium lattice was placed to cover the site and any excess graft material was removed.
An osteosynthesis screw (Ø 1.1 mm/7 mm, Meisinger, Germany) was placed using a guide hole made by Meisinger twist drill and placed with the supplied Meisinger contra-angled driver at slow speed. Good stability of the lattice was achieved with a single screw (Fig. 8); a Bio-Gide membrane (Geistlich) was cut to size and used to cover the titanium lattice (Fig. 9).
The advanced flap could be extended 4mm beyond the crestal incision and was sutured in placed with 4/0 Seralon with horizontal and vertical mattress suture, allowing tension-free closure (Fig. 10).
Post-operative care included a course of amoxicillin, 0.2% chlorhexidine rinse regime, as well as a temporary prosthesis. The patient was advised not to wear his removable partial denture for at least the first 2 weeks of healing. Due to the increased soft tissue dimensions post surgery, a suck-down splint, with the missing tooth filled with composite was fabricated by the lab technician (Neshee Gareeb, Design Ceramics). This allowed complete clearance of the soft tissue and was fully supported by the remaining dentition, which was not only well tolerated by the patient but also allowed the surgical site to heal uninterrupted.
The site was reviewed every few weeks, in case of any membrane exposure within the first 2 months. Although the exposure is common, using the mid-crestal flap, most exposures are minimal and in the author’s experience small exposures have not lead to significantly affect the resulting bone volume. The ‘Poncho technique’ has been suggested to reduce this exposure incidence, however with limited evidence-base. In this case, a small palatal exposure was observed on the post-operative CBCT scan, which did not affect the buccally positioned graft (Fig. 11).
Following a 6-month healing period, a post-operative low dose CBCT scan was taken to verify the augmented section and compared against the pre-op CBCT scan (Fig. 11). A 7mm increase in buccal width apically and an almost 6mm increase on the coronal aspect of the alveolar ridge was noted. The patient was returned to the referring dentist for the fabrication of a surgical guide and subsequent dental implant placement.
The ReOss customised titanium lattice combined with the Meisinger Screw System allows for a predictable augmentation technique that can be very time-efficient and practical for use in general practice.
The key benefits include the lack of a requirement for a bone block or the need for lattice adaptation; these combined with the efficient placement of the Mesinger Screw System, all significantly reduce surgery time and complications, ultimately improve the patient experience.
Fig 1: Exposure of bony defect
Fig 2. Digital representation of bony defect
Fig 3. Titanium lattice passive fitting
Fig 4. Digital representation of the lattice fit
Fig 5. Meisinger Trephine Basic Kit
Fig 6. Harvesting bone blocks from the ramus using Meisinger Trephine
Fig 7. Application of DBBM and autogenous bone
Fig 8. Fixation of the lattice with Meisinger screw
Fig 9. Bio-Gide covering lattice structure
Fig 10. Post-operative suturing with 4/0 Seralon
Fig 11. Pre- and post-operative CT scan of the defect
Fig 12. with post-operative CT scan, showing up to 7mm horizontal augmentation
The author would like to thank:
Meisinger, for supplying Master Pin and Screw kit along with their Trephines
Neshee Gareeb, Design Ceramics
Nesh Bangard, Geistlich, for the photography
Love Teeth Dental Practice, for the referral
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