Modern dental implantology allows to place immediate implants in post-extractive sites. This approach includes specific surgical and prosthetic procedures to prevent the loss of the buccal plate and the apical migration of the marginal soft tissue, thus maintaining aesthetics and functionality. Thanks to consolidated knowledge, experience and new technologies, it was possible to obtain systems with specific macros and microstructures. These implants, combined with autologous and/or heterologous grafts, offer a survival rate of 95%-100% and a success rate of 89%-98% for 5-10 years.
This procedure reduces the waiting time for healing and osseointegration, immediately improves the patient’s comfort with a provisional restoration and optimises the insertion of the implant while preserving the anatomical site. However, the morphology of the post-extractive alveolus is not always ideal for implant insertion. In these cases, a preliminary morpho-structural analysis identifies limits and potential, allowing a multidisciplinary reconstructive approach to be planned before or simultaneously with the extraction and insertion of the implant.
This article presents a clinical case of tooth agenesis # 2.2 and tooth persistence # 6.2, with worrying mobility. The patient, 27 years old, finished orthodontics at 15 years old and kept the space with the deciduous tooth to assess late dento-skeletal growth. This growth, which causes infraocclusion, has delayed its implantation. It is debatable whether late growth is limited to youth or persistent, and whether patients perceive it. In addition, it is evaluated what may be the ideal positioning of the implant for the prevention of an infraocclusion.
Another extremely important consideration is of a clinical-diagnostic nature for the purpose of organising a treatment plan and choosing operating procedures. In the case in question, the soft tissue phenotype, thin and scalloped, and the post-extractive alveolus, concave buccally, prevent a prosthetically guided positioning of the implant, causing severe fenestration. A contextual or deferred two-phase approach is required: reconstruction before, and then extraction with immediate implantation and restoration. This approach guarantees an optimal aesthetic result and preserves the vestibular protuberance (RBP – Root Bump Preservation), preserves the loss of crestal marginal bone giving a natural appearance of implant restorations.
Fig.1
A 27 years old male patient in good health presented due to esthetic problems when smiling related to the persistence of primary tooth # 62.
The request was to improve the smile and restore symmetry with the controlateral natural tooth.
The intraoral examination showed no evidence of periodontal problems, and a thin gingival phenotype and triangolar – shaped teeth. A preliminary esthetic analysis was considered favorable to esthetic implant due to more coronal position of the gingival margin respect the adjecent teeth.
Fig.2
Mirrored lateral incisor was digitally overlapped on tooth # 62 just to visualize a possible solution, and control its relation with the soft tissue position.
Fig.3
The digital wax-up was matched with the CBCT to preview the correct implant position in reference to the projected screw retained crown, in order to project the correct bone augmentation to prevent implant exposure, and consequently future soft tissue dehiscence.
Considering that the patient had a thin and scalloped phenotype along with triangular teeth, all conditions that predispose to gingival recession, it was decided to perform a contextually connective tissue graft together with the bone graft.
Fig.4
The bone graft has been harvested in safety by the use of a surgical guide and a piezoelectric device, which allow to make perfect osteotomy lines, avoiding to damage the below alveolar nerve.
Fig.5
The harvested bone block was shaped and fixed at the defect base to fill the defect and reproduce the radicular convexity. The gaps between the bone graft and the receiving site have been filled with particulate autologous bone.
The connective tissue graft harvested from the palate was carefully deepithelialized and prepared removing the fat tissue, and then fixed at the base of the anatomical papillae.
Fig.6
The primary flap passivated and sutured at the end of the surgery to create a perfect marginal seal.
Fig.7
Soft and hard tissues healing at 4 months.
Fig.8
a) The digital plan shows as now it is possible to insert the implant in the correct prosthetic driven position.
b) The guided surgical treatment begins with the removal of the osteosynthesis screws, and continues with the traditional surgical phases.
Fig.9
The implant was placed 1,0 mm below the bone crest, and to preserve the soft and hard tissues from the injury of a possible repeated abutment remotion, an intermediate abutment of 2,0 mm was screwed.
Fig.10
Immediate provisional screw retained crown just screwed.
Fig.11
Marginal soft tissue healing at 1 year.
Fig.12
At one year the marginal soft tissue and papillae excellent tone, shape, contour and stability. “Just ready for the final restoration”.
Fig.13
Definitive screw retained zirconia ceramic crown showing a perfect esthetic and biological integration.
Fig.14
Final X-ray at one year.
Fig.15
Lateral view.
Fig.16
At 6 years it is visible the soft and hard tissue stability, and the absence of infra-occlusion of the crown.
Conclusions
Dental implants restoration in the aesthetic area frequently requires an unconventional approach. A rigorous morpho-structural and clinical-biological analysis of the site allows you to make appropriate choices to organize the diagnosis, develop an accurate treatment plan, define specific procedures and select the most suitable materials. The primary objective is to preserve and/or improve an already ideal anatomy. Therefore, surgical and prosthetic management, closely interconnected, represents a fundamental starting point for the correct resolution of the case, in order to obtain and maintain a satisfactory functional and aesthetic result over time.
The systematic use of a screwed retained crown, both in the provisional and definitive phases, allows a rational management of the transmucosal path, coding in a first phase the trend of the concave profile and replicating its shape after healing and maturation of the tissues for the final restoration. In the specific case, the portion of the supra-crestal connective attachment of the transmucosal path was managed with an intermediate abutment 2mm height. This solution improves and protects this area during the work phases of contouring, impressions, colour testing and other procedures.
Other aspects analyzed concern infraocclusion, a phenomenon that, as anticipated in the introduction, can occur not only in young patients but also in adults. Consequently, the position of the implant during the plannning phase must take into account the possibility of correcting this phenomenon if it occurs. The correct 3D position of the recommended implant is slightly more palatal/lingual, with the exception of patients with a short face or class III. Therefore, digitally guided surgery is a further indispensable element. A possible misalignment of the parabolas, due to a different entity of growth of the jaws and teeth adjacent to the implant, can cause different forms of blemishes that can be felt by the patient. In such cases, the screw retained crown offers different possibilities for remodeling and changing in its transmucosal path to face this discomfort, if it is perceived by the patient.
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