Craniomaxillofacial Reconstructive and Corrective Bone Surgery - part 4 ppt

20B. Atlas of Cases 221 a b c e d f FIGURE 20B.1 (a) Panoramic image of a 32-year-old male with Pindborg’s tumor (CEOT) to the left. (b) Panoramic image 6 months after the operation. The border between graft and the angular area is still sharp, and the bony union is not complete. (c) Situation 14 months after the operation. There is complete bony union between graft and mandible. However, areas of bone resorption are seen within the graft. (d) Situation 27 months after the operation. The plate has been removed, and the height of the graft is preserved, but bone resorption within the graft seems to continue. (e) Cross-sec- tional tomography 27 months after operation. Two consecutive cuts. There is good cortical lining of the graft, but it has a central area of radiolucency (bone resorption). (f) A diagrammatic representation of (e). 222 C. Lindqvist, D. Hallikainen, and A L. Söderholm F IGURE 20B.2 (a) Panoramic image of a 40-year-old female 4 years after primary operation for SCC of mandibular gingiva of the mo- lar area and 20 months after transplantation of an iliac bone graft. The plate has fractured. There is good bony union medially between graft and mandible, but a defect at the angular border. (b) Cross-sec- tional tomography also shows the plate fracture. A thin bony bridge is seen lingually. (c) Panoramic image 5 months later. There is com- plete union between graft and mandible; the plate has been removed. a c b 20B. Atlas of Cases 223 a d c b e FIGURE 20B.3 (a) Panoramic image of a 23-year-old female 1 month after surgery for recurrent ameloblastoma. There is moderate re- sorption of the graft, especially in the mesial part, due to infection. (b) A diagrammatic representation of (a). (c) Panoramic image 2 months later. The resorption has increased. (d) Detailed image of the ramus area shows the contours of the graft. (e) A diagrammatic rep- resentation of (d). Continued. 224 C. Lindqvist, D. Hallikainen, and A L. Söderholm i f g h j FIGURE 20B.3 Continued. (f) Detailed image of the ramus 13 months after the operation shows good healing. (g) A diagrammatic repre- sentation of (f). (h) Detailed posteroanterior image of the condylar area. The buccal cortex is preserved, and there is complete union be- tween graft and mandible. (i) A diagrammatic representation of (h). (j) Panoramic image 4 years later. A part of the plate was removed, and dental implants with suprastructure are in use. The patient is symptom free. 20B. Atlas of Cases 225 a b c d e FIGURE 20B.4 (a) Panoramic image of a 31-year-old female shows an atypical ossifying fibroma in the mandible. (b) A diagrammatic representation of (a). (c) Cross-sectional tomography shows expan- sion and bulging of the lingual cortex and a radiolucent area at the lower border revealing that the tumor has growth potential. (Cour- tesy Pertti Paukku, M.D. Helsinki University Central Hospital, De- partment of Diagnostic Radiology.) (d) A diagrammatic representa- tion of (c). (e) Nuclear scan shows strongly increased uptake in the right mandibular body. Continued. 226 C. Lindqvist, D. Hallikainen, and A L. Söderholm F IGURE 20B.4 Continued. (f) Immediate postoperative panoramic im- age. (g) A diagrammatic representation of (f). (h) Panoramic image 3 months after surgery. There is moderate resorption of the graft but no signs of infection or loosening. (i) A diagrammatic representa- tion of (h). (j) Panoramic image 6 months after surgery. There is still a radiolucent border between graft and mandible indicating delayed union. No signs of complications. (k) A diagrammatic representa- tion of (j). f g h i j k 20B. Atlas of Cases 227 b c d e a FIGURE 20B.5 (a) This 29-year-old female has an ossifying fibroma in the mandible. CT shows the tumor expanding through the buccal cortex. (Courtesy Pertti Paukku, M.D. Helsinki University Central Hospital, Department of Diagnostic Radiology.) (b) Panoramic im- age 1 day after resection of the mandibular left body. (c) A dia- grammatic representation of (b). (d) Panoramic image 3 months af- ter transplantation of bone graft. The border between mandibular an- gle and graft is still sharp. (e) A diagrammatic representation of (d). Continued. 228 C. Lindqvist, D. Hallikainen, and A L. Söderholm f g h i FIGURE 20B.5 Continued. (f) Panoramic image 10 months after bone transplantation. There is good bony union mesially, but the distal border between graft and angle is still visible, indicating delayed union. (g) A diagrammatic representation of (f). (h) Situation 42 months after primary operation. The plate has been removed and dental implants inserted into the graft. (i) A diagrammatic represen- tation of (h). 20B. Atlas of Cases 229 a b c d e f g h FIGURE 20B.6 (a) Spontaneous fracture of irradiated edentulous mandible in a 66-year-old female. (b) A diagrammatic representa- tion of (a.) (c) Fracture stabilized with THORP. (d) A diagrammatic representation of (c). (e) Detailed image 8 months after fixation. The fracture is still visible, and there is delayed union. (f) Cross-sectional tomography of the parasymphyseal area reveals good screw fixation. There is some fragmentation of the atrophied alveolar crest. The mandibular canal is clearly visible above the screws. (g) Panoramic image taken the day after transplantation of bone graft and insertion of dental implants. (h) A diagrammatic representation of (g). Continued. 230 C. Lindqvist, D. Hallikainen, and A L. Söderholm i j m n k l FIGURE 20B.6 Continued. (i) Detailed image 1 year after graft surgery shows good bony healing. (j) A diagrammatic representation of (i). (k) Detailed image in posteroanterior direction confirms good bony union. (l) A diagrammatic representation of (k). (m) Panoramic im- age 13 months after surgery. The plate is still in place. The dental implants have been connected with a bar. (n) A diagrammatic rep- resentation of (m). [...]... arch, bone is rapidly resorbed. 24 During the first year of edentulism there is an average decrease in bone height of 4 to 5 mm in the mandible and 2 to 3 mm in the maxilla.25 A ratio of 3 or 4: 1 has been demonstrated for long-term bone loss of the mandible and maxilla, respectively Carlsson found the mean mandibular height reduction 5 years after tooth extraction to be 12.5 mm (ranging from 2 to 14. 5... 21A.16a,b) Partially Edentulous Clinicians have expanded the use of endosseous implantology to treat the partially edentulous patient Naert et al.83 demonstrated a cumulative implant success rate of 96.1% and 95.9% for the maxilla and mandible, respectively, during a 6-year prosthodontic study Jemt et al. 84 found 98.6% implant success with free-standing fixed partial prostheses after 1 year Zarb and Schmitt85,86... act as well-positioned overdenture abutments Two fixtures are placed in the cuspid sites and two just anterior to the mental foramina A clip will be placed anteriorly, and re- 242 J.H Abjanich and I.H Orenstein a b c FIGURE 21A.12 (a) Mandibular implant-supported overdenture bar, (b) denture with retentive clips, and (c) stud attachments Bar and stud attachments can significantly stabilize a mandibular... the bone and implant during healing He also suggested that bone quality may influence such factors as the drilling rate, sequence, countersinking, length and number of implants placed, healing time, occlusal scheme, and the need for progressive loading Jaffin and Berman11 reported an overall implant failure rate of 35% in quality-four (Q -4 ) bone using threaded titanium fixtures Implant design and surface... shear stresses on fixtures) Anterior Considerations poorest with Q-3 and Q -4 bone being a common finding The surgeon may prefer to use self-tapping implants in softer bone to avoid stripping bone threads, which can occur during standard tapping procedures Alternatively, press-fit implants that are easier to install may be considered Maxillary bone resorbs from buccal to lingual, often necessitating that... bone qualities Manufacturers seek to develop implant designs that lend themselves for use in poor quality bone (i.e., self-tapping implants, hydroxyapatite coatings, plasma-sprayed surfaces) It is important for the restorative dentist to consider bone quality from a biomechanical standpoint Generally, the anterior mandible has the densest bone followed by the posterior mandible, anterior maxilla, and. .. relation to the bony topography and proposed implant orientation 21A Prosthodontic Considerations in Dental Implant Restoration 233 a b FIGURE 21A.1 Surgical templates for the (a) completely and (b) partially edentulous mandible Bone Bone quality and volume are of paramount importance to the surgeon placing implants Lekholm and Zarb7 developed a system for classifying bone quality and volume that has become... compared to mandibular fixed full-arch prostheses Overdentures have several advantages over complete dentures Prosthesis retention, stability, tissue sensitivity, oral hygiene, chewing efficiency, and speech are improved Bone atrophy is reduced After the extraction of mandibular anterior teeth, there is an average of 4 mm of vertical bone loss in the first year The mandible will have a four- 241 fold greater... The posterior areas vary as potential regions for implant placement It is not uncommon to find Q -4 bone here, reinforcing the need for as much fixture support as possible The maxillary sinus may limit bone height and width There is a higher failure rate with 7-mm fixtures.76 Where less than 244 a J.H Abjanich and I.H Orenstein maxilla During the first year of function, speech problems were the most common... crown-to-implant ratio, anteroposterior (A-P) spread (to be discussed in the “Fixed Mandibular Reconstructions” section of this chapter) and opposing occlusal forces When facial support from hard and soft tissues is correct a fixed option is often preferred Trial setups with and without a flange can determine whether additional support is necessary Fixed reconstructions may be preferred when knife-edged . average decrease in bone height of 4 to 5 mm in the mandible and 2 to 3 mm in the maxilla. 25 A ratio of 3 or 4: 1 has been demonstrated for long-term bone loss of the mandible and maxilla, respectively consider bone quality from a biome- chanical standpoint. Generally, the anterior mandible has the densest bone followed by the posterior mandible, anterior maxilla, and posterior maxilla. 12 Low-density. loading. Jaffin and Berman 11 reported an overall implant failure rate of 35% in quality-four (Q -4 ) bone using threaded titanium fixtures. Implant design and surface characteristics may in- fluence