Augmentation/Transplantation in Periodontally Compromised Dentition

A non-smoking 51-year-old patient who had received various periodontal treatments at a different institution presented to us with pronounced and aggressive periodontitis [1] and unilateral free-end edentulism in the region of the left posterior maxilla. The following technical article describes how, by use of extensive periodontal measures, the periodontal and implant rehabilitation of the patient’s compromised oral condition was eventually achieved by means of an allogeneic bone-block graft (Figure 1).


The Patient Case
A non-smoking 51-year-old patient who had received various periodontal treatments at a different institution presented to us with pronounced and aggressive periodontitis [1] and unilateral free-end edentulism in the region of the left posterior maxilla. The following technical article describes how, by use of extensive periodontal measures, the periodontal and implant rehabilitation of the patient's compromised oral condition was eventually achieved by means of an allogeneic bone-block graft ( Figure 1).
The patient had been receiving periodontal treatment for five years, and two of his teeth, 26 and 27, eventually had to be removed. The clinical observation that the patient was suffering from loose teeth and gingival recession eventually brought him to our practice clinic.

Findings and Treatment
In 2015, after a comprehensive assessment and screening process, microbiological identification ( Figure 2, Hauss Laboratory, Kiel) and radiological assessment (Figure 3), the patient was initially prescribed 125 mg of amoxicillin 500/clavulanic acid (1-1-1 over 10 days) as an adjuvant to closed full-mouth curettage.
When the patient was re-evaluated, increased probing depths of up 12 mm were observed around teeth 14, 15, 24 and 25. The radiological examination revealed discernible vertical bone defects in conjunction with Bleeding on Probing (BOP), resulting in a plan to conduct regenerative periodontal surgical treatment, initially around teeth 14 and 15 (Figures 4 and 5).
A further re-evaluation 10 weeks after surgery revealed that the probing depths around teeth 14 and 15 had reduced 2,5 mm and that the patient's overall clinical picture had improved, which was due to the patient's high motivation and good cooperation ( Figure 6).

Pre-operative Planning
The following plan for 2017 was to perform open curettage of the deep vertical bone defect in tooth regions 24 and 25 in conjunction with an allogeneic bone-block graft (Zimmer Dental GmbH, Munich). With regard to tooth 25, it was explained to the patient that a decision could and would have to be made intra-operatively whether to retain the tooth by means of regenerative measures, based on the experiences of Cortellini P, et al. [2], or to remove it.
The alveolar ridge of tooth regions 26 and 27, which was affected by severe three-dimensional atrophy, was to be reconstructed with an allogeneic bone block. A CT scan was taken to help plan the surgery. This was used as the basis for the fabrication of a 3D bone block. The CT data were sent in DICOM format to Zimmer Dental GmbH, Munich for virtual graft planning (Figures 7 and 8).
The analysis strikingly revealed, more so than the planning, the periodontal defect of vertical bone loss in tooth regions 24 and 25. Figures 9 and 10 shows the virtual planning after grafting the bone block onto the defective area.
The material used to fabricate the individual bone blocks is processed human cancellous bone (from living donors only) (Puros Allograft, Zimmer Dental GmbH, Munich) [3].

Surgical Protocol
In January 2017, the defective regions around teeth 24-27 were imaged under intubation anaesthesia.
The representation of the surgical site by the previously prepared full flap revealed a pronounced vertical bone defect around teeth 24 and 25; tooth 24 was only attached to the bone by its apex. Based on the available evidence about regenerative measures and because           This was followed by tension-free suture closure using absorbable sutures (Glycolon 6/0, Resorba. Figure 16 shows the situation one day after surgery, Figure 17 eight days after surgery.

Sci Forschen
The patient received intra-operative antibiotic prophylaxis of 1000 mg amoxicillin i.v. He also received postoperative antibiotic prophylaxis of 1000 mg amoxicillin (1-1-1) and 500 mg metronidazole for ten days (1-1-1). He was instructed to rinse his mouth with a 0.2% chlorhexidine solution and to use chlorhexidine gel in his dental-care routine. Figure 18 shows the postoperative orthopantomogram.
After a six-month healing period of the augmentation material, surgical re-entry was performed. This showed that the graft had ossified normally (Figure 19).
The micro fixtures were removed and two implants (diameter: 4 mm, length: 11.5 mm; Zimmer Biomet) were inserted in tooth regions 26 and 27 during a simultaneous direct sinus lift. Autogenous bone chips were removed from the oblique ridge using a Safe Scraper. These chips were used to shape uneven areas in the region of insertion of the patient's extremely high compliance, the defect was filled in with a xenogeneic bone (Bio Oss collagen, Fa. Geistlich) replacement material after extensive open curettage (smoothing of the root surface, complete removal of the granulation tissue with the aid of the piezosurgery technique; (Figures 11 and 12) and the application of PrefGel™ and Emdogain® (Straumann GmbH). The filled defect was then covered with an absorbable membrane.
While this was taking place, the allogeneic bone-block graft was prepared using sodium chloride (Figure 13).
The bone block was fixed in place by use of osteosynthesis screws (Ustomed) and small uneven patches were levelled out using a particulate allogeneic substitute material (Puros Allograft Spongiosa Partikel [cancellous bone particles], Zimmer Dental GmbH, Munich) ( Figure 1).
The augmentation material and augmented regions around teeth 24 and 25 were covered with an absorbable collagen membrane (CopiOs Pericardium Membrane, Zimmer Dental GmbH, Munich) and fixed in place with Titan Pins (Ustomed) (Figures 14 and 15).    and to augment the sinus. The area was covered with an absorbable membrane applied using the bi-layer technique (Bio Gide, Fa Geistlich GmbH) (Figures 20-25).
After a further six-month implant-healing period, the implants were then surgically uncovered by use of combined soft-tissue grafts and a scaffold (mucoderm, Straumann GmbH; Figure 26).
Note the periodontal regeneration of the area around tooth 25, which can also be clinically observed in figures 30 and 31.

Discussion
In the context of classic treatment concepts, teeth with bone resorption of 75% and above are classified as hopeless [4]. Such teeth are usually extracted. The previously mentioned 2011 study by Cortellini P [2], however, reports a 92% five-year incidence of survival for "hopeless" teeth. This means that, even in extreme cases, a patient's desire to retain their teeth can be met by means of regenerative periodontal surgical measures. The patient case described here also

Conclusion
The present patient case shows that even a periodontally compromised dentition is regenerative, augmentative and implantologically treatable. A comprehensive diagnosis, an evaluation of causal inter-connections and a specific, individualized treatment are indispensable. Especially with such multifactorial findings and therapies a close recall is mandatory and a high motivation and commitment of the patient an indispensable prerequisite.