Patient AW, a 37 year old male was referred in August 2004, by his general dental practitioner seeking advice and options for the treatment of failing crowns on the four upper anterior teeth, with a history of repeated loosening and recementation.

His medical history was clear and he was a non-smoker. Examination identified a normal physiognomy with some loss of anterior lip support due to absence of the anterior crowns. TMJ examination revealed no pain, crepitus, deviation or limitation of opening.

His lip line was low and periodontally there was no bone loss and no periodontal pocketing over 3mm and except for a slight degree of inflammatory gingivitis his oral hygiene was assessed as average. He presented as having gingival tissue of thick biotype.

Crowns at 12 11 22 were lost and the root faces and post preparations were extensively carious even below the gingival margins. The crown on 21 was present though mobile and the root similarly carious. The roots were not tender to percussion, showed no sign of discharge and the radiographs evidenced no extensive periapical pathology.

Fig 1. Panoramic Radiograph- Pre-operative

The shape of the remaining crown at 21 was essentially rectangular and the assumption was made that this probably replicated his original natural crown shape. The occlusion was normal.

The bone level around the carious roots and adjacent teeth  13 and 23 was good, there being no significant bone loss. The lower left first molar was fractured and showed periapical pathology and this was to be removed by the patient’s general dental practitioner.

Fig 2. Frontal view of anterior situation

The width of the alveolar ridge between the canine teeth 13 and 23 was of normal dimensions allowing for restoration with incisor teeth of normal dimensions and no complex aesthetic considerations. The alveolar ridge had no defects horizontally or vertically. Soft tissues were likewise intact with no defects, dehiscences or evidence of apical discharge.

The patients level of co-operation was good and he responded well to advice on the need for improved and sustained oral hygiene. Treatment expectations were reasonable and the complexity of the case was assessed as routine.

Following the clinical examination, treatment options were considered and discussed with their various advantages and disadvantages.

Table 1      

The patient elected to proceed with the last option, immediate implant placement with a temporary denture and delayed loading was the chosen protocol based on the following factors:

• Alveolar ridge anatomy was favourable, vertically and horizontally.
• Primary stability would be achievable
• Absence of acute infection around roots
• Atraumatic extraction was deemed possible
• Bone category was assessed as Type 2
• Thick gingival Bio-type
• Submucosal healing
• Delayed loading
• Good level of patient co-operation
• Patient a non-smoker

Further consideration was then given to the possible positioning of the implants:

1. In the central incisor positions with pontics for the lateral incisors
2. Asymmetrical positioning, one central incisor and one contra- lateral incisor
3. In the lateral incisor sockets with central incisor pontics.

This latter was favoured as it avoided undue aesthetic complications of adjacent implants and the lateral incisor sockets in this case provided for long implant length and more complete bone implant interface, due to the relative narrowness of the lateral incisor sockets compared with the intended diameter of the implants.

A temporary acrylic partial immediate denture was made and also used as a guide for implant placement and final aesthetics.

Implants chosen were Astra ST 5.0mm x 19 mm.

Surgery was carried out under local anaesthesia in August 2004, under antibiotic cover of 3g oral amoxicillin, and the four roots were removed with a periotome, and following debridement and curettage of the sockets, osteotomy preparation was commenced in the 12, 22 sockets, initially with an entry bur to define positioning just palatal to the socket apex.

Preparation was completed with Twist Drills under copious saline irrigation and finally the 5.0mm Profile Drill. Implants were inserted manually and checked with the Torque Wrench set to 35ncm. The implants were placed approximately 0.5mm to 1.0 mm below the socket crests to allow for slight resorbtion following immediate placement, and small quantity of autogenous bone particles (harvested with a Bone Trap) and a little Bio Oss was packed into the very small defects between the implant Microthread and socket walls.

Closure screws were placed on the implants to 10ncm torque and the sockets at 11 and 21 were packed with resorbable collagen sponge and some remaining autogenous bone particulate after confirming the continued integrity of the buccal socket walls and crestal bone. Closure of the sockets was with 5/0 Vicryl . The immediate partial denture was adjusted so as to put no undue pressure on the sockets. Healing was uneventful and the sutures were removed after ten days.

Three months later December 2004 the patient returned for the second stage surgery. Healing of the soft tissue was good and healing caps were fitted to form the gingival cuff.

Two weeks later the peri-implant tissue showed an impressive level of health.

Fig 3. Gingival cuff on removal of Zebra healing caps

A cement retained four unit bridge was planned and fixture head impressions were taken using an open tray technique, a stock tray using a polysiloxane putty and syringe material. Face bow and centric bite registration were completed.

Fig 4. Impression transfers in place for open tray impression

Abutment selection was made following discussion with the laboratory and it was agreed that the chosen abutments, though not angled, would require some preparation to maximize aesthetics. To facilitate the correct alignment of the abutments in the implants two “abutment positioning jigs” were made in resin to fit over the patients natural canine teeth before final fitting.

Fig 5. Acrylic jig for accurate positioning of abutments

Shade selection was made with the patient’s approval and the laboratory work was completed.

Fig 6. Finished prosthesis on model

In January 2005, the finished bridge was delivered and abutments seated with the jigs, and tightened to 20ncm.

The bridge was seated, checked in centric occlusion and in lateral excursions and then cemented – the good passive fit and soft tissue recovery identified by just a little blanching and displacement of the gingival tissue following cementation.

The patient was very satisfied with the result, and was referred back to his general dental practitioner. The prosthesis  has now been in function for over three years.

Fig 7. Finished Case

Fig 8. Radiograph - 3 years after implant placement