Immediate or delayed placement? Implant planning and guided surgery. 5 May 2014

Clinical case

Patient's request and general health

A 54 year-old woman referred by her attending practitioner for an implant-borne prosthetic rehabilitation. This patient has aesthetic grievances and complains of halitosis.

In terms of general health, we observe that:

She suffers from a corrected thyroid deficiency (following the thyroid removal due to cancer)
She does not smoke
She has no parafunctional habit.

October 2009
Clinical and radiographic examination

The patient shows:

An unsightly smile with a high smile line (Fig. 1);
Transversal disharmony of the arches;
An important vertical dimension of the vestibule and unsightly prosthetic space;
A maxillary dental protrusion, important overbite and overjet;
Severe and generalized chronic periodontitis with osteolysis reaching the apical third, suppuration and furcation (Fig. 2 and 3);
Dental mobility;
Defective endodontics associated with outbreaks;
An overhanging restoration on 35.

Fig.1: Analysis of the patient's unsightly and high gingival smile which displays the dental necks..

Fig.2: Vestibular view where we observe gingival inflammation, recessions and the non-alignment of dental necks.

Fig. 3: Initial panoramic X-ray showing generalised osseous loss reaching the apical third, periapical and furcation lesions.

Treatment decision - Maxilla

Extraction of all maxillary teeth and implementation of an immediate removable complete denture (IRCD). In our case, the necessary use of an IRCD reduces crestal bone at the time of extractions in order to raise the prosthesis/soft tissue junction line and, then, to restore the plans of occlusion.
Planning of the fixed implant-borne prosthetic rehabilitation using simulation software (NobelClinician) with immediate loading.
Rehabilitation of a final implant-borne prosthesis with a screw-retained maxillary bridge on 6 implants.

October 2009

Atraumatic extractions of teeth 47 and 36 after a supportive periodontal therapy by her attending practitioner.

December 2009

Extraction of all maxillary teeth.
Adjustment of the crestal bone in order to solve the gingival smile issue and to apicalise the prosthesis/soft tissue junction (Fig. 4).
Filling of the extraction sockets with autogenous bone retrieved during the extractions with gouge forceps and mixed with bovine hydroxyapatite (Bio-Oss®, Geistlich), all of which are covered with collagen membranes (Bio-Guide®, Geistlich).
Placement of an immediate provisional removable denture.

Fig. 4: Extraction of teeth 17, 16, 13, 12, 11, 21, 22, 23, 24, 25 and 27 with adjustment of the crestal bone in order to raise the prosthesis/soft tissue junction.

May 2010

3D examination: the complete removable prosthesis (CRP) is made into a radiological guide with placement of radio-opaque markers. 2 scans are then performed: the first one, of the patient with the CRP in her mouth; the second one, of the CRP alone.
The software integrates the compiled data in order to visualise the prosthetic project and the patient's anatomical data simultaneously, which will allow for planning of the surgical procedure in which the implants, their position, orientation and emergence profiles will be chosen based on the pre-established and previously validated prosthetic project thanks to the removable prosthesis (Fig. 5).

Fig. 5: Planning of implant choices, their position, orientation and emergence profiles with the NobelClinician software according to the prosthetic project and the available osseous volume. Note the stabilisation anchor pins which must not interfere with the implants.

June 2010

Reception of the surgical guide produced by stereolitography. With the help of a dental rim and by fixing it with anchor pins (Fig. 6), it will guide the placement of 6 (NobelSpeedy, Nobel Biocare) implants with precision.

Fig. 6: NobelGuide surgical guide in place on surgery day; drilling and implant placement is done through the guide.

The operation is performed without any incisions or sutures and it is flapless (Fig. 7).

Fig. 7: Implants are placed in the transgingival position without incisions or sutures and are flapless.

Placement of an immediate prosthesis just after the operation, although produced beforehand thanks to the surgical guide, from which a working model will be cast from the same guide (Fig. 8-9).
This prosthesis is screw-retained on conical abutments (MUA, Nobel Biocare), (Prosthesis Théodore Abillama, Laboratory Didier RAUX).
Extractions of 35 and 37 and placement of 3 Branemark Mk III (Nobel Biocare) implants on 36 and 46 and a NobelSpeedy (Nobel Biocare) on 35.

Fig. 8: Provisional prosthesis, produced beforehand from the model of the surgical guide, in place on the day of the surgery.

Fig. 9: Panoramic X-ray with the provisional prosthesis in place showing the voluntary angulation of the distal implants and planned according to the patient's anatomy.

November and December 2010

Removal of the provisional bridge and validation of the osseointegration of each implant.
Rehabilitation of the implant-borne final prosthesis (Fig. 10) with the help of a titanium screw-retained fixed prosthesis on implant bars (PIB, Procera Implant Bridge, Nobel Biocare).

Fig. 10: View of the patient's new smile clearly showing the importance of lopping and, therefore, raising the prosthesis/soft tissue junction.

Porcelain teeth are used in the maxilla (IVOCLAR) except on 15 and 25 where the resin allows access to the screws of the prosthesis (Prosthesis Théodore Abillama, Laboratory Didier RAUX).
Cement-retained all-ceramic caps in the mandible on zirconia anatomic abutments (Procera, Nobel Biocare), (Laboratory PHB Montrouge).

March 2014 - Check-up at 3 years and 9 months

A yearly supportive implant treatment is provided with a clinical and radiographic examination as well as a periodontal maintenance.
The bone level is stable and we observe slight retraction of the mucosa around the implants, although this does not yet affect the function nor the aesthetics (Fig. 11-12).

Fig. 11: Radiographic results at 3 years and 9 months showing the stability of the bone level around the implants.

Fig. 12:Vestibular view at 3 years and 9 months with the final prosthesis on titanium framework (PIB). Note the buccal flange used to correct the lop necessary to raise the smile line.

Discussion

With implant planning on simulation software it is possible to visualise the previously chosen and validated prosthetic project through the complete denture from an aesthetic as well as a functional and occlusal point of view. Thus, it optimises the implant choice, its diameter, length, angulation, positioning and emergence profile while taking into account the osseous volume of the patient and any anatomical obstacle.
As such, this computer planning results in a surgical guide produced by stereolitography and allows:

Precise transfer to the mouth of this information , in particular for edentulous patients whereby a traditional guide has limited stability and, thus, a relatively random precision of the position and the axis of the implants;
Flapless, simplified and predictable surgery;
Reduced operation time on the chair-side for the patient and for the surgeon;
Simpler post-operative follow-ups for the patient;
Additional indications including for patients treated with anticoagulant or antiplatelet drugs;
Manufacturing of a provisional prosthesis prior to implant placement which will be placed in the mouth on the day of the surgery.

This approach, which remains substantially related to the experience of the treatment team, requires comfortable crestal bone volume, but is of great interest to the edentulous patient.

Authors

Hadi Antoun

Private practice limited to Periodontology and Implantology
Paris, Founder of the IFCIA Institute.

Ons Zouiten

Doctor in dental surgery
Postgraduate degree in Periodontics, Paris 5 University
Postgraduate degree in implantology – Paris 6 University
Private practice in Orléans

Michel Karouni

Doctor in Dental Surgery,
Postgraduate degree in periodontics and fixed prosthesis – University Paris 7