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cone beam – international magazine of cone beam dentistry

use of CBCT case report | 05 cone beam 2 2016 Case This article discusses the unexpected findings that continuouslyemergedthroughoutthetreatmentpro- cess due to the absence of CBCT imaging in the initial phaseofdiagnosis,aswellastheinsufficiencyofpan- oramic radiographic images in that clinical situation. The patient’s initial situation was characterised by a losethree-unitfixedpartialdenture,45implantsup- ported, 46 pontic and 47 implant supported. Initially, the patient opposed the use of a radiograph and, as a consequence, the need for implant extraction was misdiagnosed. Eventually, in order to complete the extraction, all three types of common radiography techniques—periapical,panoramicandCBCT5—were needed and applied.5,7,10 Themaincomplaintofthe65-year-oldnon-smoking male with no medical history or use of medication was “my bridge is moving and requires re-cement- ing”. During an emergency appointment, the patient enquired about the costs for the re-cementing of a three-unit bridge. The patient presented a six- month-old periapical radiograph (Fig. 1a) while de- clining to take any further X-rays for a simple bridge re-cementing procedure. According to the patient, the implants were placed five years ago and without incisionbyanow-retireddentistwhocouldnolonger be contacted. After analysing the radiograph and making a clinical assessment, the provisional diag- nosis showed that the bridge was moving due to an abutment screw loosening (Fig. 2). The resulting treatment plan called for the removal of the three- unit bridge and the re-tightening of the abutment screw to the manufacturers recommended preload as well as the re-cementing of the bridge (plan A). The patient approved the suggested procedures and signedthetreatmentplan.Thebridgewasfoundtobe firmly attached to the anterior implant and loosely connected to the posterior one. The existing bridge had to be cut out and replaced by a new three-unit bridge (plan B). A small opening of the screw access hole was attempted on both implant restorations 45 and 47 (Fig. 3). Although the access hole did not lead to the abutment screw, the bridge mobility was in- creased.Aperiapicalradiographwasobtainedtoeval- uate the peri-implant status of the posterior implant (Fig.1b).Theradiolucencyobservedaroundthefixture indicatedimplantfailureandthecrownintheanterior implanthadtobesacrificedinordertogettoitsabut- mentsafely.Atthisstage(planC),theprocedureswere set out as follows: removal of the posterior implant followed by a re-implant, a new temporary crown on tooth 45 and, after two months, fitting of a two-unit bridge instead of the previous three-unit bridge res- toration. This decision resulted from the fact that the mesio-distal length of the bridge required to accom- modate three teeth was 18mm and not 21mm. Theheightoftheextractedimplantandtheavailable bonewas8mmwhenthepanoramicimagewaseval- uated (Fig. 4). As the available diagnosis information did not provide data regarding the desired diameter and angulation of the implant to be placed, the pa- Fig. 1b Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 1a: Periapical radiograph. Fig. 1b: Digital periapical radiograph. Fig. 2: Occlusal view of the bridge. Fig. 3: Occlusal view after attempting to get to the abutment. Fig. 4: Panoramic radiograph, diagnosis. Fig. 5: Occlusal view of PFM bridge. Fig. 1a 22016