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Dental CT Imaging: A Look at the Jaw¹

¹ From the Department of Diagnostic Radiology, Yale University School of Medicine, 333 Cedar St (CB-30), PO Box 208042, New Haven, CT 06520-8042. Received May 13, 1999; revision requested June 29; revision received January 20, 2000; accepted February 11. Address correspondence to the author (e-mail: abrahams@biomed.med.yale.edu).

View larger version (191K): [in a new window]   Figure 1a. Dental CT scans in 24-year-old woman with periapical radiolucency in the left canine tooth from endodontal disease. (a) Transverse image shows where the cursor is deposited (curved arrows) for the program to produce a curved line (straight arrow) that defines the location for reformatting the panoramic image in c. Perpendicular numbered lines (arrowheads) define where cross-sectional images in d are reformatted. (b) Transverse image shows the appearance of the target due to the opaque root in the center of the radiolucency (arrowheads). (c) Panoramic image shows an area of sclerotic condensing osteitis (arrowheads) surrounding a periapical radiolucency (arrow). The dentine (D), dense enamel (E), pulp chamber (Pc), and root canal (Rc) are nicely depicted. (d) Cross-sectional views show the relation of the periapical radiolucency (arrowheads) to the buccal (solid arrow) and lingual (open arrow) cortex. (Reprinted, with permission, from reference 1.)

View larger version (163K): [in a new window]   Figure 1b. Dental CT scans in 24-year-old woman with periapical radiolucency in the left canine tooth from endodontal disease. (a) Transverse image shows where the cursor is deposited (curved arrows) for the program to produce a curved line (straight arrow) that defines the location for reformatting the panoramic image in c. Perpendicular numbered lines (arrowheads) define where cross-sectional images in d are reformatted. (b) Transverse image shows the appearance of the target due to the opaque root in the center of the radiolucency (arrowheads). (c) Panoramic image shows an area of sclerotic condensing osteitis (arrowheads) surrounding a periapical radiolucency (arrow). The dentine (D), dense enamel (E), pulp chamber (Pc), and root canal (Rc) are nicely depicted. (d) Cross-sectional views show the relation of the periapical radiolucency (arrowheads) to the buccal (solid arrow) and lingual (open arrow) cortex. (Reprinted, with permission, from reference 1.)

View larger version (76K): [in a new window]   Figure 1c. Dental CT scans in 24-year-old woman with periapical radiolucency in the left canine tooth from endodontal disease. (a) Transverse image shows where the cursor is deposited (curved arrows) for the program to produce a curved line (straight arrow) that defines the location for reformatting the panoramic image in c. Perpendicular numbered lines (arrowheads) define where cross-sectional images in d are reformatted. (b) Transverse image shows the appearance of the target due to the opaque root in the center of the radiolucency (arrowheads). (c) Panoramic image shows an area of sclerotic condensing osteitis (arrowheads) surrounding a periapical radiolucency (arrow). The dentine (D), dense enamel (E), pulp chamber (Pc), and root canal (Rc) are nicely depicted. (d) Cross-sectional views show the relation of the periapical radiolucency (arrowheads) to the buccal (solid arrow) and lingual (open arrow) cortex. (Reprinted, with permission, from reference 1.)

View larger version (67K): [in a new window]   Figure 1d. Dental CT scans in 24-year-old woman with periapical radiolucency in the left canine tooth from endodontal disease. (a) Transverse image shows where the cursor is deposited (curved arrows) for the program to produce a curved line (straight arrow) that defines the location for reformatting the panoramic image in c. Perpendicular numbered lines (arrowheads) define where cross-sectional images in d are reformatted. (b) Transverse image shows the appearance of the target due to the opaque root in the center of the radiolucency (arrowheads). (c) Panoramic image shows an area of sclerotic condensing osteitis (arrowheads) surrounding a periapical radiolucency (arrow). The dentine (D), dense enamel (E), pulp chamber (Pc), and root canal (Rc) are nicely depicted. (d) Cross-sectional views show the relation of the periapical radiolucency (arrowheads) to the buccal (solid arrow) and lingual (open arrow) cortex. (Reprinted, with permission, from reference 1.)

View larger version (66K): [in a new window]   Figure 2. Illustration of the components of an implant—prosthesis screw (Ps), abutment screw (As), abutment (A), and fixture (F)—and two dental implants supporting a three-tooth prosthesis. Black portion (long arrow) represents the metal framework within the prosthesis. Note how the location of neurovascular bundle in the mandibular canal (short arrow) must be established to prevent injury during implant placement. (Reprinted, with permission, from reference 1.)

View larger version (167K): [in a new window]   Figure 3a. Images show the clinical use of the dental CT program and show the dental implant surgical procedure. (a) Photograph shows a patient edentulous distal to the right maxillary canine (short arrow) being evaluated for dental implants. A plastic stent with six vertical markers is placed over the alveolar ridge and residual teeth. The sixth marker (long arrow) is adjacent to the right canine and is demonstrated in b and c. (b) Transverse CT image demonstrates the sixth marker as a dot (long thick arrow) at perpendicular line 32 (long thin arrow) adjacent to the right canine (short arrow). (c) Cross-sectional CT views demonstrate markers four (straight open arrow), five (large straight solid arrow), and six (curved solid arrow) of the stent as lines. Note that marker six is adjacent to the right canine (curved open arrow). By placing a stent on the patient during surgery, the surgeon knows that the bone under marker six is as depicted on cross-sectional image 32. Arrowheads indicate where alveolar bone width is measured; small straight solid arrows indicate where height is measured. (d) An incision is made, and the gingival and periosteal flaps (arrowheads) are held back with sutures, exposing the bone of the alveolar process (short arrows). Holes are drilled, and three titanium implants are inserted into the bone. Note that the implants are flush with the bone, and their openings are covered with healing screw caps (long arrow). (e) The incision is sutured closed, and after 4-6 months of healing, permanent abutments, which raise the fixture above the gingival surface, are attached with abutment screws. Screw hole in the center of the abutment (arrow) accommodates a screw that fixes the prosthesis. (f) Prosthesis is now attached to three implants. Screw heads are covered with white compound. (Reprinted, with permission, from reference 14.)

View larger version (156K): [in a new window]   Figure 3b. Images show the clinical use of the dental CT program and show the dental implant surgical procedure. (a) Photograph shows a patient edentulous distal to the right maxillary canine (short arrow) being evaluated for dental implants. A plastic stent with six vertical markers is placed over the alveolar ridge and residual teeth. The sixth marker (long arrow) is adjacent to the right canine and is demonstrated in b and c. (b) Transverse CT image demonstrates the sixth marker as a dot (long thick arrow) at perpendicular line 32 (long thin arrow) adjacent to the right canine (short arrow). (c) Cross-sectional CT views demonstrate markers four (straight open arrow), five (large straight solid arrow), and six (curved solid arrow) of the stent as lines. Note that marker six is adjacent to the right canine (curved open arrow). By placing a stent on the patient during surgery, the surgeon knows that the bone under marker six is as depicted on cross-sectional image 32. Arrowheads indicate where alveolar bone width is measured; small straight solid arrows indicate where height is measured. (d) An incision is made, and the gingival and periosteal flaps (arrowheads) are held back with sutures, exposing the bone of the alveolar process (short arrows). Holes are drilled, and three titanium implants are inserted into the bone. Note that the implants are flush with the bone, and their openings are covered with healing screw caps (long arrow). (e) The incision is sutured closed, and after 4-6 months of healing, permanent abutments, which raise the fixture above the gingival surface, are attached with abutment screws. Screw hole in the center of the abutment (arrow) accommodates a screw that fixes the prosthesis. (f) Prosthesis is now attached to three implants. Screw heads are covered with white compound. (Reprinted, with permission, from reference 14.)

View larger version (162K): [in a new window]   Figure 3c. Images show the clinical use of the dental CT program and show the dental implant surgical procedure. (a) Photograph shows a patient edentulous distal to the right maxillary canine (short arrow) being evaluated for dental implants. A plastic stent with six vertical markers is placed over the alveolar ridge and residual teeth. The sixth marker (long arrow) is adjacent to the right canine and is demonstrated in b and c. (b) Transverse CT image demonstrates the sixth marker as a dot (long thick arrow) at perpendicular line 32 (long thin arrow) adjacent to the right canine (short arrow). (c) Cross-sectional CT views demonstrate markers four (straight open arrow), five (large straight solid arrow), and six (curved solid arrow) of the stent as lines. Note that marker six is adjacent to the right canine (curved open arrow). By placing a stent on the patient during surgery, the surgeon knows that the bone under marker six is as depicted on cross-sectional image 32. Arrowheads indicate where alveolar bone width is measured; small straight solid arrows indicate where height is measured. (d) An incision is made, and the gingival and periosteal flaps (arrowheads) are held back with sutures, exposing the bone of the alveolar process (short arrows). Holes are drilled, and three titanium implants are inserted into the bone. Note that the implants are flush with the bone, and their openings are covered with healing screw caps (long arrow). (e) The incision is sutured closed, and after 4-6 months of healing, permanent abutments, which raise the fixture above the gingival surface, are attached with abutment screws. Screw hole in the center of the abutment (arrow) accommodates a screw that fixes the prosthesis. (f) Prosthesis is now attached to three implants. Screw heads are covered with white compound. (Reprinted, with permission, from reference 14.)

View larger version (122K): [in a new window]   Figure 3d. Images show the clinical use of the dental CT program and show the dental implant surgical procedure. (a) Photograph shows a patient edentulous distal to the right maxillary canine (short arrow) being evaluated for dental implants. A plastic stent with six vertical markers is placed over the alveolar ridge and residual teeth. The sixth marker (long arrow) is adjacent to the right canine and is demonstrated in b and c. (b) Transverse CT image demonstrates the sixth marker as a dot (long thick arrow) at perpendicular line 32 (long thin arrow) adjacent to the right canine (short arrow). (c) Cross-sectional CT views demonstrate markers four (straight open arrow), five (large straight solid arrow), and six (curved solid arrow) of the stent as lines. Note that marker six is adjacent to the right canine (curved open arrow). By placing a stent on the patient during surgery, the surgeon knows that the bone under marker six is as depicted on cross-sectional image 32. Arrowheads indicate where alveolar bone width is measured; small straight solid arrows indicate where height is measured. (d) An incision is made, and the gingival and periosteal flaps (arrowheads) are held back with sutures, exposing the bone of the alveolar process (short arrows). Holes are drilled, and three titanium implants are inserted into the bone. Note that the implants are flush with the bone, and their openings are covered with healing screw caps (long arrow). (e) The incision is sutured closed, and after 4-6 months of healing, permanent abutments, which raise the fixture above the gingival surface, are attached with abutment screws. Screw hole in the center of the abutment (arrow) accommodates a screw that fixes the prosthesis. (f) Prosthesis is now attached to three implants. Screw heads are covered with white compound. (Reprinted, with permission, from reference 14.)

View larger version (124K): [in a new window]   Figure 3e. Images show the clinical use of the dental CT program and show the dental implant surgical procedure. (a) Photograph shows a patient edentulous distal to the right maxillary canine (short arrow) being evaluated for dental implants. A plastic stent with six vertical markers is placed over the alveolar ridge and residual teeth. The sixth marker (long arrow) is adjacent to the right canine and is demonstrated in b and c. (b) Transverse CT image demonstrates the sixth marker as a dot (long thick arrow) at perpendicular line 32 (long thin arrow) adjacent to the right canine (short arrow). (c) Cross-sectional CT views demonstrate markers four (straight open arrow), five (large straight solid arrow), and six (curved solid arrow) of the stent as lines. Note that marker six is adjacent to the right canine (curved open arrow). By placing a stent on the patient during surgery, the surgeon knows that the bone under marker six is as depicted on cross-sectional image 32. Arrowheads indicate where alveolar bone width is measured; small straight solid arrows indicate where height is measured. (d) An incision is made, and the gingival and periosteal flaps (arrowheads) are held back with sutures, exposing the bone of the alveolar process (short arrows). Holes are drilled, and three titanium implants are inserted into the bone. Note that the implants are flush with the bone, and their openings are covered with healing screw caps (long arrow). (e) The incision is sutured closed, and after 4-6 months of healing, permanent abutments, which raise the fixture above the gingival surface, are attached with abutment screws. Screw hole in the center of the abutment (arrow) accommodates a screw that fixes the prosthesis. (f) Prosthesis is now attached to three implants. Screw heads are covered with white compound. (Reprinted, with permission, from reference 14.)

View larger version (135K): [in a new window]   Figure 3f. Images show the clinical use of the dental CT program and show the dental implant surgical procedure. (a) Photograph shows a patient edentulous distal to the right maxillary canine (short arrow) being evaluated for dental implants. A plastic stent with six vertical markers is placed over the alveolar ridge and residual teeth. The sixth marker (long arrow) is adjacent to the right canine and is demonstrated in b and c. (b) Transverse CT image demonstrates the sixth marker as a dot (long thick arrow) at perpendicular line 32 (long thin arrow) adjacent to the right canine (short arrow). (c) Cross-sectional CT views demonstrate markers four (straight open arrow), five (large straight solid arrow), and six (curved solid arrow) of the stent as lines. Note that marker six is adjacent to the right canine (curved open arrow). By placing a stent on the patient during surgery, the surgeon knows that the bone under marker six is as depicted on cross-sectional image 32. Arrowheads indicate where alveolar bone width is measured; small straight solid arrows indicate where height is measured. (d) An incision is made, and the gingival and periosteal flaps (arrowheads) are held back with sutures, exposing the bone of the alveolar process (short arrows). Holes are drilled, and three titanium implants are inserted into the bone. Note that the implants are flush with the bone, and their openings are covered with healing screw caps (long arrow). (e) The incision is sutured closed, and after 4-6 months of healing, permanent abutments, which raise the fixture above the gingival surface, are attached with abutment screws. Screw hole in the center of the abutment (arrow) accommodates a screw that fixes the prosthesis. (f) Prosthesis is now attached to three implants. Screw heads are covered with white compound. (Reprinted, with permission, from reference 14.)

View larger version (49K): [in a new window]   Figure 4a. (a) Illustration of normal tooth anatomy. A = apical foramen, C = cementum, D = dentine, E = enamel, G = gingiva, L = lamina dura, N = neurovascular bundle, P = periodontal ligament, Pc = pulp chamber, R = root canal. (b) Illustration of dental caries (curved solid arrow), which allow bacteria to enter the pulp chamber and travel down the root canal to the apical foramen (arrowhead), where a periapical radiolucency develops (open arrows). Note how increased pressure from pulpitis compromises the blood supply to the tooth (straight solid arrow), rendering it nonvital. (Reprinted, with permission, from reference 8.)

View larger version (42K): [in a new window]   Figure 4b. (a) Illustration of normal tooth anatomy. A = apical foramen, C = cementum, D = dentine, E = enamel, G = gingiva, L = lamina dura, N = neurovascular bundle, P = periodontal ligament, Pc = pulp chamber, R = root canal. (b) Illustration of dental caries (curved solid arrow), which allow bacteria to enter the pulp chamber and travel down the root canal to the apical foramen (arrowhead), where a periapical radiolucency develops (open arrows). Note how increased pressure from pulpitis compromises the blood supply to the tooth (straight solid arrow), rendering it nonvital. (Reprinted, with permission, from reference 8.)

View larger version (74K): [in a new window]   Figure 5. Panoramic dental CT scan in a 52-year-old man with a small periapical lesion (straight white arrows) from endodontal disease that surrounds a zone of condensing osteitis (arrowheads). Note that the radiopaque post (black arrows) from a root canal procedure fills the root canal. Compare this with the normal radiolucent root canal in the adjacent tooth (curved white arrow). (Reprinted, with permission, from reference 8.)

View larger version (75K): [in a new window]   Figure 6. Panoramic dental CT scan in a 60-year-old man with advanced periodontal (arrowheads) and endodontal (straight arrows) lesions. Note how periodontal disease travels down the sides of the root, while endodontal disease affects the root apex. A radiopaque post from a root canal procedure is seen in a tooth with an endodontal lesion (curved arrow). (Reprinted, with permission, from reference 14.)

View larger version (160K): [in a new window]   Figure 7a. CT images in a 64-year-old patient with endodontal and periodontal disease extending into the maxillary sinus. (a) On transverse view, inflammation has the appearance of polyps or retention cysts (arrow). (b) The panoramic view, however, reveals mounds of inflammation (straight arrows) centered over the root apex of the teeth, which are affected by advanced endodontal and periodontal disease. Note the resorption of bone due to the infection (arrowheads) and the empty socket (curved arrow), where the tooth was lost because of periodontal disease. m = maxillary sinus, n = nasal turbinate. (Reprinted, with permission, from reference 8.)

View larger version (79K): [in a new window]   Figure 7b. CT images in a 64-year-old patient with endodontal and periodontal disease extending into the maxillary sinus. (a) On transverse view, inflammation has the appearance of polyps or retention cysts (arrow). (b) The panoramic view, however, reveals mounds of inflammation (straight arrows) centered over the root apex of the teeth, which are affected by advanced endodontal and periodontal disease. Note the resorption of bone due to the infection (arrowheads) and the empty socket (curved arrow), where the tooth was lost because of periodontal disease. m = maxillary sinus, n = nasal turbinate. (Reprinted, with permission, from reference 8.)

View larger version (39K): [in a new window]   Figure 8a. Illustrations of a periodontal pocket and its treatment. (a) On the right, a normal periodontal ligament is depicted (thick arrows). On the left, the portion affected by periodontal disease results in a periodontal pocket (thin arrow), with resorption of adjacent bone (arrowheads). (b) The periodontal pocket is treated by filling it with freeze-dried bone (curved arrow), by placing a expanded polytetrafluoroethylene membrane (straight arrow) between soft tissues, and by performing a bone graft to prevent soft-tissue ingrowth. (Reprinted, with permission, from reference 8.)

View larger version (45K): [in a new window]   Figure 8b. Illustrations of a periodontal pocket and its treatment. (a) On the right, a normal periodontal ligament is depicted (thick arrows). On the left, the portion affected by periodontal disease results in a periodontal pocket (thin arrow), with resorption of adjacent bone (arrowheads). (b) The periodontal pocket is treated by filling it with freeze-dried bone (curved arrow), by placing a expanded polytetrafluoroethylene membrane (straight arrow) between soft tissues, and by performing a bone graft to prevent soft-tissue ingrowth. (Reprinted, with permission, from reference 8.)

View larger version (110K): [in a new window]   Figure 9a. Photographs in a patient with a large periodontal pocket treated with an expanded polytetrafluoroethylene membrane and freeze-dried bone. (a) Soft tissue is retracted, exposing bone (arrowheads) and the periodontal pocket (straight arrows). Note the exposed root (curved arrow) caused by bone resorption. (b) The defect is packed with freeze-dried bone (arrowheads). (c) The membrane is placed over the bone graft, and the soft tissue is sutured closed to cover it. The edge of the membrane (arrowheads) is depicted between the bone graft and soft tissue. (Reprinted, with permission, from reference 17.)

View larger version (111K): [in a new window]   Figure 9b. Photographs in a patient with a large periodontal pocket treated with an expanded polytetrafluoroethylene membrane and freeze-dried bone. (a) Soft tissue is retracted, exposing bone (arrowheads) and the periodontal pocket (straight arrows). Note the exposed root (curved arrow) caused by bone resorption. (b) The defect is packed with freeze-dried bone (arrowheads). (c) The membrane is placed over the bone graft, and the soft tissue is sutured closed to cover it. The edge of the membrane (arrowheads) is depicted between the bone graft and soft tissue. (Reprinted, with permission, from reference 17.)

View larger version (105K): [in a new window]   Figure 9c. Photographs in a patient with a large periodontal pocket treated with an expanded polytetrafluoroethylene membrane and freeze-dried bone. (a) Soft tissue is retracted, exposing bone (arrowheads) and the periodontal pocket (straight arrows). Note the exposed root (curved arrow) caused by bone resorption. (b) The defect is packed with freeze-dried bone (arrowheads). (c) The membrane is placed over the bone graft, and the soft tissue is sutured closed to cover it. The edge of the membrane (arrowheads) is depicted between the bone graft and soft tissue. (Reprinted, with permission, from reference 17.)

View larger version (117K): [in a new window]   Figure 10a. Coronal diagrams of the maxillary sinus show the sinus lift procedure. (a) The bone flap (arrow) created by means of osteotomy is pushed inward with the maxillary sinus membrane (arrowheads) to create a space (S) that is packed with the bone graft material depicted in b. (b) Image shows the bone graft filling space created with the inward displacement the osteotomy and sinus membrane. (Reprinted, with permission, from reference 8.)

View larger version (141K): [in a new window]   Figure 10b. Coronal diagrams of the maxillary sinus show the sinus lift procedure. (a) The bone flap (arrow) created by means of osteotomy is pushed inward with the maxillary sinus membrane (arrowheads) to create a space (S) that is packed with the bone graft material depicted in b. (b) Image shows the bone graft filling space created with the inward displacement the osteotomy and sinus membrane. (Reprinted, with permission, from reference 8.)

View larger version (118K): [in a new window]   Figure 11. Cross-sectional dental CT image shows the sinus lift procedure in an edentulous patient with severe alveolar process atrophy. Note how the graft (G) has created ample bone for implantation in a patient who initially had almost no available bone. (Reprinted, with permission, from reference 20.)

View larger version (86K): [in a new window]   Figure 12. Cross-sectional dental CT images of the mandible show healing after genioplasty in a patient suspected of having nonunion. Note the osteotomy (arrows), which allows anterior advancement of inferior mandible (arrowheads).

View larger version (91K): [in a new window]   Figure 13. Cross-sectional dental CT images of the mandible show a silicone implant (arrows) eroding the mandible and compromising the root apex (arrowhead). (Reprinted, with permission, from reference 11.)

View larger version (127K): [in a new window]   Figure 14. Cross-sectional dental CT image of the maxilla shows an oroantral fistula (arrow). Note that a streak artifact (arrowheads) is projected horizontally over the crowns of the teeth rather than over the bone. Also note fluid in the sinus (S). (Reprinted, with permission, from reference 10.)

View larger version (137K): [in a new window]   Figure 15a. Images in a 9-year-old girl with a calcifying odontogenic cyst. (a) Panoramic radiograph shows a double cortex (arrowheads) due to cortical expansion, but one cannot determine whether buccal or lingual cortex is involved. Also, the margins of the lesion are poorly defined, the neurovascular bundle is not intensified, and the superimposition of an ectopic tooth (arrow) makes it difficult to determine if resorption of left first bicuspid (b) root has occurred. (b) Panoramic dental CT scan permits better visualization of the lesion (solid arrow), ectopic tooth (open arrow), and mandibular canal (arrowheads). b = first left bicuspid. (c) Cross-sectional dental CT scans clearly demonstrate expansion of the buccal cortex (arrowheads), two unerupted teeth within the lesion (open and thin solid arrows), an erupted left first bicuspid (b), and displacement of mandibular canal (thick solid arrows). (Reprinted, with permission, from reference 7.)

View larger version (136K): [in a new window]   Figure 15b. Images in a 9-year-old girl with a calcifying odontogenic cyst. (a) Panoramic radiograph shows a double cortex (arrowheads) due to cortical expansion, but one cannot determine whether buccal or lingual cortex is involved. Also, the margins of the lesion are poorly defined, the neurovascular bundle is not intensified, and the superimposition of an ectopic tooth (arrow) makes it difficult to determine if resorption of left first bicuspid (b) root has occurred. (b) Panoramic dental CT scan permits better visualization of the lesion (solid arrow), ectopic tooth (open arrow), and mandibular canal (arrowheads). b = first left bicuspid. (c) Cross-sectional dental CT scans clearly demonstrate expansion of the buccal cortex (arrowheads), two unerupted teeth within the lesion (open and thin solid arrows), an erupted left first bicuspid (b), and displacement of mandibular canal (thick solid arrows). (Reprinted, with permission, from reference 7.)

View larger version (138K): [in a new window]   Figure 15c. Images in a 9-year-old girl with a calcifying odontogenic cyst. (a) Panoramic radiograph shows a double cortex (arrowheads) due to cortical expansion, but one cannot determine whether buccal or lingual cortex is involved. Also, the margins of the lesion are poorly defined, the neurovascular bundle is not intensified, and the superimposition of an ectopic tooth (arrow) makes it difficult to determine if resorption of left first bicuspid (b) root has occurred. (b) Panoramic dental CT scan permits better visualization of the lesion (solid arrow), ectopic tooth (open arrow), and mandibular canal (arrowheads). b = first left bicuspid. (c) Cross-sectional dental CT scans clearly demonstrate expansion of the buccal cortex (arrowheads), two unerupted teeth within the lesion (open and thin solid arrows), an erupted left first bicuspid (b), and displacement of mandibular canal (thick solid arrows). (Reprinted, with permission, from reference 7.)

View larger version (73K): [in a new window]   Figure 16a. Images in a 14-year-old male adolescent with a dentigerous cyst in an unerupted left cuspid. (a) Orthopantomogram shows the dentigerous cyst (arrowheads) twice because of distortion near the midline. Note that the root of the retained primary cuspid (baby tooth) on the left (short arrow) is much shorter than the root of the permanent cuspid on the right (long arrow). (b) Panoramic dental CT scan better delineates the unerupted left cuspid with the dentigerous cyst (arrowheads) that surrounds the crown of tooth. The primary left cuspid with a short root (short arrow) and the permanent right cuspid (long arrow) are again depicted. (c) Cross-sectional dental CT images show the relation of the lesion to the right (R) and left (L) central incisors. Note that the cyst (arrowheads) abuts the roots but does not cause resorption. (Reprinted, with permission, from reference 7.)

View larger version (70K): [in a new window]   Figure 16b. Images in a 14-year-old male adolescent with a dentigerous cyst in an unerupted left cuspid. (a) Orthopantomogram shows the dentigerous cyst (arrowheads) twice because of distortion near the midline. Note that the root of the retained primary cuspid (baby tooth) on the left (short arrow) is much shorter than the root of the permanent cuspid on the right (long arrow). (b) Panoramic dental CT scan better delineates the unerupted left cuspid with the dentigerous cyst (arrowheads) that surrounds the crown of tooth. The primary left cuspid with a short root (short arrow) and the permanent right cuspid (long arrow) are again depicted. (c) Cross-sectional dental CT images show the relation of the lesion to the right (R) and left (L) central incisors. Note that the cyst (arrowheads) abuts the roots but does not cause resorption. (Reprinted, with permission, from reference 7.)

View larger version (115K): [in a new window]   Figure 16c. Images in a 14-year-old male adolescent with a dentigerous cyst in an unerupted left cuspid. (a) Orthopantomogram shows the dentigerous cyst (arrowheads) twice because of distortion near the midline. Note that the root of the retained primary cuspid (baby tooth) on the left (short arrow) is much shorter than the root of the permanent cuspid on the right (long arrow). (b) Panoramic dental CT scan better delineates the unerupted left cuspid with the dentigerous cyst (arrowheads) that surrounds the crown of tooth. The primary left cuspid with a short root (short arrow) and the permanent right cuspid (long arrow) are again depicted. (c) Cross-sectional dental CT images show the relation of the lesion to the right (R) and left (L) central incisors. Note that the cyst (arrowheads) abuts the roots but does not cause resorption. (Reprinted, with permission, from reference 7.)

View larger version (139K): [in a new window]   Figure 17a. Squamous cell carcinoma of the oral cavity invading the mandible. (a) Transverse view shows destruction (arrowheads) of the mandible and cortex, without expansion of the jaw. Note involvement of the mandibular canal (arrow). Compare these findings with those on the normal left side. (b) Cross-sectional dental CT scans again show destruction of the cortex (arrowheads) and involvement of the superior aspect of the mandibular canal (arrow). Note that signs of a benign lesion, bone expansion, and mandibular canal displacement are absent in this malignancy. Compare these findings with those of the benign lesion in Figure 15c.

View larger version (62K): [in a new window]   Figure 17b. Squamous cell carcinoma of the oral cavity invading the mandible. (a) Transverse view shows destruction (arrowheads) of the mandible and cortex, without expansion of the jaw. Note involvement of the mandibular canal (arrow). Compare these findings with those on the normal left side. (b) Cross-sectional dental CT scans again show destruction of the cortex (arrowheads) and involvement of the superior aspect of the mandibular canal (arrow). Note that signs of a benign lesion, bone expansion, and mandibular canal displacement are absent in this malignancy. Compare these findings with those of the benign lesion in Figure 15c.

View larger version (152K): [in a new window]   Figure 18a. Images in a 46-year-old man with periodontal disease causing bone resorption of the right and left first molar root furcation and with endodontal disease causing periapical radiolucency in the left central incisor. (a) On the conventional dental radiograph, roots are superimposed, making it difficult to determine which roots have bone loss and whether periodontal disease affects root furcation. Bone resorption (arrowheads) is depicted along the sides of the roots. (b) Transverse CT image more easily reveals that radiolucency due to bone resorption involves the root furcations of the first molars (short arrows). Note also the large periapical radiolucency (long arrow) in the left central incisor caused by endodontal disease. (c) Cross-sectional CT image optimally shows the radiolucency in the first molar root furcation (arrows). Dentin (d), dense enamel (e), and pulp (p) are also nicely depicted. m = maxillary sinus. (Reprinted, with permission, from reference 8.)

View larger version (132K): [in a new window]   Figure 18b. Images in a 46-year-old man with periodontal disease causing bone resorption of the right and left first molar root furcation and with endodontal disease causing periapical radiolucency in the left central incisor. (a) On the conventional dental radiograph, roots are superimposed, making it difficult to determine which roots have bone loss and whether periodontal disease affects root furcation. Bone resorption (arrowheads) is depicted along the sides of the roots. (b) Transverse CT image more easily reveals that radiolucency due to bone resorption involves the root furcations of the first molars (short arrows). Note also the large periapical radiolucency (long arrow) in the left central incisor caused by endodontal disease. (c) Cross-sectional CT image optimally shows the radiolucency in the first molar root furcation (arrows). Dentin (d), dense enamel (e), and pulp (p) are also nicely depicted. m = maxillary sinus. (Reprinted, with permission, from reference 8.)

View larger version (109K): [in a new window]   Figure 18c. Images in a 46-year-old man with periodontal disease causing bone resorption of the right and left first molar root furcation and with endodontal disease causing periapical radiolucency in the left central incisor. (a) On the conventional dental radiograph, roots are superimposed, making it difficult to determine which roots have bone loss and whether periodontal disease affects root furcation. Bone resorption (arrowheads) is depicted along the sides of the roots. (b) Transverse CT image more easily reveals that radiolucency due to bone resorption involves the root furcations of the first molars (short arrows). Note also the large periapical radiolucency (long arrow) in the left central incisor caused by endodontal disease. (c) Cross-sectional CT image optimally shows the radiolucency in the first molar root furcation (arrows). Dentin (d), dense enamel (e), and pulp (p) are also nicely depicted. m = maxillary sinus. (Reprinted, with permission, from reference 8.)