Palatal Insertion of Upper Canine Immediate Implant
When the tooth is extracted, the buccal plate is found completely missing. Osteotomy is initiated in the palatal wall of the socket and leaned as palatal as possible (Fig.1). When a 5x20 mm implant (Fig.2,3 I, insertion torque 50/60 Ncm) and a 4x5 mm abutment (A) are placed, palatal reduction has to be done for an immediate provisional (Fig.4 P). When the latter is seated, a coronal portion of the implant is exposed (Fig.4 I). After placement of Osteotape (collagen membrane impregnated with Hydroapaptite, Impladent) against the buccal defect, bone graft is packed as deep as possible (Fig.2 *) and covers the exposed implant surface (Fig.5 B). The latter is covered by Osteotape. Following provisional cementation, perio dressing is applied to keep the last collagen membrane in place.
The patient returns asymptomatic 1 week postop. The perio dressing is stable (Fig.6 D). There is no sign of infection buccally (Fig.6) or lingually (Fig.7), although the excess lingual margin of the provisional is to be trimmed (Fig.7 *).
When the provisional is dislodged 2 weeks postop, some of bone graft is lost (Fig.8 ^). The implant/abutment is reprep (Fig.9,10); the provisional is relined and recemented (Fig.11, the buccal margin is intentionally trimmed short so that the gingiva may grow coronally). The infection is reduced (Fig.11 *, compare to Fig.4,5). There appears to be initial mild buccal plate collapse (Fig.12 arrowheads). Three weeks later (after last provisional trimming), the gingiva at #11 has grown downward (Fig.13 arrow, as compared to Fig.11); the fistula has turned into normal tissue (*). The buccal plate remains minimally collapsed (Fig.14).
The most prominent feature of this case is dislodgement and even breakdown (1.5 months postop) of the immediate provisional in spite of repeated reline. It is due to excessive canine guidance. The abutment needs to trimmed short (Fig.15 A), especially distolingual surface. Not only is there enough clearance between the abutment and the tooth #21 in centric occlusion (Fig.16), but also during lateral movement (Fig.17). The distolingual portion of the provisional and the future permanent crown should be fabricated thin to reduce occlusal trauma. Fig.18 is for shade selection. Examination of the extracted tooth reveals calculus deposit in the apical third of the root (Fig.19 >).
Three months post cementation (5 months postop), the patient returns for follow up. There is a crater-like defect at the crest (Fig.20 *). Although the buccal plate over the crown (Fig.21 C) is concave (arrowheads), there is no metal exposure or gingival recession (Fig.22).
The crown is dislodged 13 months post cementation in spite of resin bonding. It appears that the crown was not seated completely upon cementation, since the resin cement is quite thick. When the crown is reseated after cement is removed, it is not tight until the crown is forced to be seated completely. Finally the crown is recemented with resin bonding (Fig.23). It appears that more bone is deposited on the most coronal thread.
On the other hand, the abutment is somewhat short. If the crown is dislodged again, a longer or larger abutment (9 mm, as compared to 5 mm initially or 4.5x5 mm instead of 4x5 mm) will be used. Before change in abutment, take Alginate impression for record so that there will be the same amount of clearance when a new abutment is prepared. It would be the best to fabricate a new provisional to test the retention of the new abutment. There appears no bone loss 3 years post cementation (Fig.24).
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Canine Immediate Implant,
Xin Wei, DDS, PhD, MS 1st edition 03/23/2015, last revision 06/19/2018