(To see the pictures referred to in this article please see the digital version on the right, page 48)
Comprehensive rehabilitation requires knowledge. Not only of the patient’s wishes and perceptions of treatment outcomes, but detailed knowledge of the scientific literature in order to be able to plan at the outset. How to achieve the desired result, and how to progress if, and when problems occur.
The following case study is over a 10-year period and details how potential problems, which ultimately occurred, were mitigated from the outset.
Patient: 47-year-old fit and healthy male.
Reason for referral: recently had to have two upper posterior bridges removed due to recurrent caries (bridges had provided good service for approx 10 years). Patient wants missing teeth replaced with fixed solution rather than removable. Would like a predictable long-term result. (Figs 1-4)
Problem list: potential for recurrent caries, heavily restored dentition, root filled potential abutment teeth with evidence of apical pathology, evidence of parafunction, open margin on remaining cantilever bridge.
1. Dental implant supported bridgework.
2. Conventional re-treatment with fixed crown and bridgework.
The patient requested to investigate the possibility of conventional re-treatment. Discussions were had explaining:
1. Potential prognosis of fixed bridgework and the reduction on these percentages based on degree of previous restoration, bruxism and recurrent caries. No guarantee on longevity could be provided and the patient would have to accept full responsibility for a compromise option.
2. Integrity of existing root canal fillings would need to be assessed, with possible repetition.
3. Potential for root canal therapy on teeth previously deemed vital, either during this course of treatment or in the future.
4. Explanation that for a number of teeth, due to degree of previous restoration any further problems would necessitate extraction.
5. It would be necessary to control potential parafunctional activities with an occlusal night guard.
6. Full explanation of operative procedures and the need to approach in a staged manner.
Provided with all the necessary information on which to make an informed decision and on the basis that dental implant treatment would still be possible in the future, the patient requested to proceed with conventional re-treatment.
Stage one: Detailed assessment of all potential abutment teeth. Patient was referred to specialist endodontist who advised:
1. Re-treatment of 24 and 26.
2. Accepting 13 and 17.
Stage two: preparation of abutment teeth
1. On separate occasions, all abutment teeth were prepared to include removal of existing coronal restorations and assessment for sufficient coronal tooth structure to allow confidence for cast restoration support. Where necessary, bone removal crown lengthening was carried out to ensure that all margins would be on sound dentine and easily cleansable. Two millimetre anterior ferrules were established. (Fig 6)
2. New cores were placed in teeth 17, 24 and 27 comprising direct placement titanium post and composite cores anteriorly with amalgam cores posteriorly. (Fig 7)
3. Occlusion was adjusted to even contacts in centric relation posteriorly, no eccentrics and shallow anterior guidance.
4. Pattern resin copings and facebow records were made to allow for transferring of individual dies to a master model and confirmation of occlusion. (Figs 8-9)
5. Bridges were designed lsquo;stress brokenrsquo; with fixed/moveable cast joints. (Fig 10)
6. On completion of treatment, an occlusal night guard for the upper arch of lsquo;Michiganrsquo; or lsquo;flat planersquo; design was fabricated and fitted. (Figs 11-13)
Stage three: maintenance
The patient was instructed on the correct home care regime required, suggested follow up scheduling and use of the nocturnal appliance. The patient was returned to his referring practitioner.
Patient was re-referred five years later as tooth 23 had failed.
Tooth 23 had developed periapical periodontitis and root canal therapy had been carried out through the previously placed two-unit cantilever bridge.
Unfortunately post preparation had resulted in a lateral perforation. Specialist endodontic opinion had been sought and a surgical repair of the perforation carried out, together with buccal root amputation of tooth 24. Subsequently the bridge had fractured off at the gingival margin, and a buccal sinus had developed. The patient was now wearing a temporary denture over the retained root. The patient again requested a fixed final result. (Fig 14)
Additional Problem list:
1. Compromised tooth – unsaveable.
2. Significant mobility of tooth 24, due to reduced support and all occlusal guidance now being transferred to it and associated bridgework.
All other restorations were functioning satisfactorily with no evidence of recurrent caries. Patient had been wearing the nocturnal splint up until tooth 23 fractured off and a denture was required.
Treatment discussion and options presented:
1. Replacement of teeth 22 and 23 with implant supported splinted units on two implants.
2. Replacement of teeth 22, 23, 24 and 25 with implant supported splinted units on three dental implants.
The patient was advised, and agreed, that given the potential for failure of tooth 24 the wisest option would be replacement of teeth 22, 23, 24 and 25 with implant supported bridgework.
Stage one: elimination of infection and stabilisation
The bridge was sectioned anterior to 26 and teeth 23, 24 extracted. The area was allowed to heal for four months prior to review radiographs and surgical planning. A provisional partial denture was used during the treatment period.
Stage two: implant surgery
Three implants were placed at 23, 24, and 25 positions.
Although primary stability was achieved it was less than ideal for all implants and extensive guided bone regeneration was necessary with a direct osteotome sinus lift procedure being carried out for the implant at 25.
Stage three: reconstruction
All implants successfully integrated. Due to the implant at 23 being slightly too buccally positioned it was necessary to fabricate cemented bridgework. In order to allow for use of a lsquo;softrsquo; cement and retrievability a horizontal set screw was positioned palatally. (Figs 16-18)
Stage four: maintenance
A new nocturnal appliance was fabricated and the patient instructed on the correct home care for the implant supported restorations.
Follow up: after a further three years all restorations were functioning satisfactorily. (Figs 19-20)
Future management: replacement of bridge URQ with implant supported when failure necessitates.
With restorative dentistry failure is, ultimately, a common occurrence. We often quote percentage success rates to patients as a means of allowing them to make informed decisions.
It is also essential that when planning extensive restoration we take the time to discuss how failure may be managed, not only does this reinforce the problems as being the patients, but in many cases this will have an effect on the initial treatment option decision.
This case history was provided by Kevin Lochhead of Edinburgh Dental Specialists. Acknowledgment and thanks for excellent laboratory work to Portland Ceramics and Edinburgh Dental Implant Laboratory.