Immediate loading: a comfortable solution for the patient 28 June 2017

 

 

Immediate loading: a comfortable solution for the patient.

In this issue of the "IFCIA Newsletter", we are dealing with complete oral rehabilitation after the extraction of multiple teeth, placement of implants, MCI and prosthetic construction. The use of simple and accurate protocols enabled us to optimise the restoration of the masticatory function and the aesthetic requests of the patient.

 

Case history and clinical examination

Mrs G.P., a 57 year-old, has a consultation due to permanent, daily inconveniences.  She has difficulty when chewing. Her fixed prosthetic reconstructions are permanently receding and they are no longer functionally or aesthetically satisfactory. Her medical history underlines that she used to be a smoker.

As of today, the patient wishes "to be able to eat and smile normally".  This request, in regards to present anatomical data, raises the level of demand.

On exobuccal examination, an oval-shaped face, straight and satisfactory width, opening and closing pathway are observed. The ATM are asymptomatic.  (Fig. 1a and b).

 

Figure 1a and 1b: When the patient smiles normally, the Cupid's bow of the top lip disappears. The lips are stretched and thin, showing an imposing gum line and undercutting of the vestibular surfaces of the maxillary teeth reaching the molars. The aesthetic challenge is confirmed.

 

An aesthetic analysis reveals a large gingival smile (high smile line) and a slight deviation from the interinal midlines.  One observes that the lower facial regions are slightly enlarged.

On intraoral examination, the gingiva inflammation is associated with plaque, tartar, multiple recessions and overcontoured maxillary bridge prosthetic elements. The cervical line is irregular. (Fig. 2a, b and c).

 

 

Figure 2a , 2b and 2c: The absence of a larger contour line at incisor and canine level shows long unanimated teeth. The central incisors are asymmetric. The volumetric proportions are incoherent with the lateral ones.

 

Performance wise, the occlusion is stable. The prosthetic construction previously performed ensured adjustment, centering and lateral canine guidance. The anterior guidance excursion during propulsion is regular.

The periodontal condition signals gingivitis associated with deep pockets, with attachment loss of up to 9mm. The periodontal biotype is relatively thick.

 

 

Attachment loss measurement and X-ray examination

 

Figure 3: Measuring the attachment loss directs leads us towards a diagnosis of severe, generalised chronic periodontitis.

 

A cone beam CT and panoramic X-ray enables us to objectify severe, horizontal osseous loss, as well as the presence of profound carious and endodontic lesions at maxillary bridgeworks abutment level. These teeth can be considered non-conservable.

Horizontal osseous loss can be observed on the mandible at the apical third, particularly at incisor level as well as a furcation defect at 46.

 

Figure 4a and 4b: The panoramic X-ray and cone beam CT objectify the extent of the radicular decay as well as the periodontal osseous loss. The residual sinus floor bone is diminished on first reading.

 

The CBCT of the maxilla shows limited bone quality and quantity but it authorises the indication of extractions and immediate implant placement.  (Fig. 5).

 

Figure 5: On the cone beam CT, the vestibular and palatal cortical bones of the anterior maxilla are present and continuous. The medullary space is just large enough for implants with an adapted diameter.

 

 

Treatment plan

 

Let's sum up some key points that will guide us in determining the treatment plan:

• The high smile line the patient wishes to keep;
• Insufficient oral hygiene;
• Severe, chronic periodontitis;
• Guarded prognosis for the maxillary teeth and mandibular incisors;
• Adequate osseous volume for immediate implant placement.

At dental level, total maxilla rehabilitation is necessary, contrary to the mandible which only requires partial rehabilitation.

The treatment plan consists of profound periodontal treatment in phase one. At 3 months, the pre-prosthetic preparation is carried out prior to immediate implant placement in the maxilla and mandible. At 4 months, the provisional bridgeworks are re-assessed. At 6 months, the final bridgeworks can begin.

Treatment

 

 

 

A - Phase One: Pre-prosthetic study and extractions

During periodontal debridement therapy, the maxillary molars are extracted and the bridgeworks are sectioned.  Thus, the pre-prosthetic phase begins. It is necessary to include the fitting of a resin teeth mounting on a wax base to view an anterior sector cervical line in harmony with the smile line. At this stage, we observe the need to shorten the future mandibular incisors.

The initial mounting made on an articulator is validated in the mouth. With patient approval, the additions are scheduled to position the cervical line in the desired place.  (Fig. 6a, b and c) (Fig. 7a, b and c).

Figure. 6a: On the articulator, the silicon mould allows the position of the incisal guidance of the anterior maxillary teeth to be recorded.
  This reference shall be used for the mounting guide.

 

Figure 6b and 6c: The use of resin shells on the plaster model allows us to position the dental necks in relation to the upper lip.

 

Figure 7c: The Curve of Spee of the mandibular incisors is recovered and idealised.

 

Figure 7c: The Curve of Spee of the mandibular incisors is recovered and idealised..

The recorded intermaxillary relationship must be reproducible, repeatable and well chosen in the three dimensions of the space. This means that on the day of the MCI, the same intermaxillary relationship can be recognised, thus sparing biomechanical restraints for the implants.

This data, stored by the prosthetist, will be used to develop a polymerised mounting guide. It will be used as a surgical guide to position implants in the buccal corridor, then as a dental tray for immediate loading. (Fig. 8a and b)

Fig. 8a and 8b: A transparent resin surgical guide is made using the mounting guide. It is a guide for totally guided surgery with drills for the drilling and insertion of implants.

 

B - Phase two: maxillary surgery and impression:

As seen on the CBCT, the osseous volume is sufficient enough for extraction implantation and immediate loading. 13, 14 and 23 are extracted using an atraumatic approach.

A crestal incision at 17 and 27 with posterior discharge allows the full-thickness flap to be lifted. (Fig. 9a and b)

 

Fig. 9a and 9b: Atraumatic extraction of the remaining teeth and lifting of the full-thickness flap over the whole of the rest with discharges at 17 and 27.

 

A small window is made on the left in order to objectify the medial sinus wall, thus preventing it from effraction while the implant is being positioned in 25 which will be distally inclined.

The disinfected guide is put in place with the help of a resin occlusion mould. It is screwed so that it is well fixed during the procedure. It is a guide with drill sleeves (Nobel Guide®) used to carry out guided surgery. Six Nobel Active®  (Nobel Biocare) implants are positioned in the anterior sector with a primary stability of at least 35 N.cm allowing loading. (Figs 10a to d:) The conical loading abutments (Multi Unit Abutment, Nobel Biocare) are tightened to 35 N.cm (Fig 11) and the impression copings are put in place. (Fig. 12). The extraction sites are filled with Bio-Oss® (Geistlich). The discontinued 5/0 resorbable (Velosorb, IPP Pharma) sutures close the edges of the wound.

 

Figs. 10b, 10c and 10d : The disinfected guide is positioned with the help of a resin occlusion mould. It is important to ensure they have been put in place properly. It is fixed with the help of an osteosynthesis screw at vestibule level on top of 11 and 12 then the drilling is carried out and the implants are placed using adapted drill sleeves.

Figure 11: The implants are placed in the buccal corridor at the level of sites 11, 21, 13, 23, 15 and 25. The sleeves are milled and the conical abutments  (Multi Unit Abutement, Nobel Biocare®) are put in place.

Figure 12 : The flap is closed with discontinued sutures around the copings that have been put in place.

Once the copings are connected, a dental dam is put in place to protect the mucous membranes and isolate the suture strings. The guide is repositioned avoiding any interference with the copings. The creation of vestibular windows allows us to inject the composite resin to cement the copings. The impression is taken in occlusion. Since the resin is polymerised, open mouth, composite resin is tagged on at deficit level. At the end of this phase, the copings are unscrewed and the caps are placed onto the conical abutments. (Fig. 13 a, b and c).

Figure 13a and 13b: The guide is going to be used as a dental tray at present. A dental dam is positioned to protected the flap. A check is made to ensure that the copings do not surpass the occlusal edge of the guide.  Perforations are carried out on the guide in relation to the copings. The composite resin is injected at this level to link the copings to each other.

 

Figure 13c: The guide is removed and the missing ones are completed. The occlusion is re-indexed directly onto the guide with the Duralay resin material.

 

The impression is sent to the prosthetist who will then use all the information to make the provisional bridgeworks as quickly as possible; in our case, it will be provided the following day.

This provisional bridgeworks is put in 24H after the operation. It is screw-retained in the mouth with multi-unit abutments. (Fig. 14).

Fig. 14: The temporary implant-borne bridge is put in place 24 hours later. A slight occlusal equilibration is made to distribute the contacts evenly.

The patient will wear this prosthesis for 6 months. The patient must be seen 15 days and 6 weeks after the MCI is fitted.

C - Third phase: Mandible surgery and replacement of incisors.

Mandible rehabilitation begins three months after maxillary surgery. 45 and 46 are extracted in parallel with the mandibular incisors. Remember that these teeth, 32 to 42, are affected by terminal periodontis. (Fig. 15 and 16).

Figure 15: Cone beam CT of the anterior mandibular sector. The osseous volume allows immediate extraction implantation.

 

Figure 16: Cone beam CT of section 4 at the level of 45 and 46. The alveolar nerve is at distance. The osseous loss in terms of46 confirms that a GBR will be required.

For the anterior sector, flapless surgery  is taken on. Immediate implant placement and provisionalisation is performed. To carry out this procedure, provisional bridgeworks with the prepared teeth in the resin are constructed on the working model. The perforations are made based on the future position of the implants. Titanium cylinders (provisional components) are adjusted at the level of the perforations. Surgery is directed based on the bridgeworks perforations. (Fig. 17) (Fig. 18a to c).

Figure 17: Occlusal view of provisional components connected on 3 implants put in place with the help of a provisional bridgeworks without lifting the flap. It involves 3 small Brånemark MK3® (Nobel Biocare) implants with a external connection.