PMC5902124_01
Preliminary clinical evaluation of the patient: (a) maxilla intraoral frontal view; (b) maxilla intraoral occlusal view; (c) mandible intraoral occlusal view.
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fig1
A 58-year-old man presented few natural teeth in the upper jaw (dental elements 1.2, 1.1, and 2.2) and long-term complete mandibular edentulism (Figure 1).
Views of preliminary CBCT evidencing sufficient bone volume in the anterior maxilla and poor bone in the lower jaw except for the interforaminal area: (a) panorex reconstruction; (b) maxilla view; (c) mandible view.
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Diagnostic wax-up realized on stone models put in medium-values articulator prior (a, b) and after (c, d) simulating teeth extraction.
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After having simulated maxillary teeth extraction on the upper working model, both stone models were put in a medium-values articulator to realize the diagnostic wax-up in order to previsualize the aesthetic result, also considering the extraction of the residual teeth (Figure 3).
(a) Stone model scanning; (b) coupling DICOM files from CBCT with STL files from model scan; (c, d) computer planning of implant position.
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Once having digitally reproduced the diagnostic wax-up, the position of the implants was planned, considering the bone availability and in a prosthetically driven approach in order to have a favourable emergence of the prosthetic screws (Figure 4).
(a) Occlusal view of the teeth-supported maxillary-guided surgical template; (b) maxillary model with analogues inserted in correspondence of planned implant position; (c) maxillary metal-reinforced acrylic provisional prosthesis.
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fig5
In laboratory, the implant analogues were inserted into the model, and a metal-reinforced acrylic provisional prosthesis:1.5 mm diameter steel bar reinforcement:(Acry Pol LL, Ruthinium Group, Badia Polesine, Italy) to be relined on the abutments in the patient's mouth after the implant positioning was produced based on the diagnostic wax-up (Figure 5).
(a) In-mouth try-in of the maxillary teeth-supported surgical template; (b) positioning of the superior dental implants with the aid of the surgical guide; (c) five dental implants positioned in the maxilla before teeth extraction; (d) clinical aspect after teeth extraction.
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All the implants showed an insertion torque higher than 45 N cm, so the remaining teeth could be removed (Figure 6), postextractive alveoli were filled with collagen sponges, and screwed provisional prosthesis was delivered.
(a, b) View of the provisional upper prosthesis after in-mouth direct abutment fixing; (c) occlusal view of the prosthesis after screwing; (d) frontal view.
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fig7
Technologies Ltd.), which height had been previously studied in laboratory in order not to protrude occlusally from the provisional prosthesis, were screwed on the implants, and metal-reinforced resin provisional prosthesis was directly relined and fixed on the abutments with resin (Splintline, Lang Dental Mfg. Co. Inc., Wheeling, IL) and then refined and polished in the dental laboratory and finally placed in the mouth (Figure 7). The provisional prosthesis was screwed on the implants and tightened at 25 N cm, and then the holes for screws were filled with light-curing resin.
OPG performed after maxillary rehabilitation.
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Final orthopantomography (OPG) was performed to control implant insertion and prosthesis fitting (Figure 8).
Planning of lower intervention: (a) radiological acrylic template with radiopaque markers; (b, c) virtual planning of implant insertion.
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fig9
The implant insertion was virtually planned as previously described (Figure 9).
(a) Coronal view of the mandibular guided surgical template; (b) a particular of the mandible model with temporary abutments screwed on the analogues inserted in correspondence of planned implant position; (c) occlusal and (d) frontal views of mandible metal-reinforced acrylic provisional prosthesis.
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fig10
Files deriving from the project were processed, and the surgical template, the acrylic model, and the provisional prostheses were produced as described above (Figure 10).
(a) Surgical template seated on the mandible model and put in medium-values articulator for the realization of the silicon index; (b) detail of the three-dimensional relationship between maxilla and mandible models.
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(a) Clinical setting of the template through the silicon index; (b) occlusal view of the inferior implant inserted before removing the surgical template; (c) provisional restorations.
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As all implants showed an insertion torque higher than 45 N cm, the patient could receive provisional prosthesis at the same time of surgery, following the same protocol as for the maxilla (Figure 12).
Definitive PMMA monolithic restoration: (a) frontal view; (b) right-side view; (c) left-side view; (d) occlusal view of the maxillary arch; (e) frontal view of the maxillary arch; (f) occlusal view of the mandibular arch; (g) frontal view of the mandibular arch; (h) detail of the frontal bite.
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(a) Clinical and (b) radiographical aspect of the definitive restoration after 1 year follow-up.
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Good clinical and radiographic results could be reported, with no sign of soft tissue inflammation and limited bone resorption around the implant necks (Figure 14).