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To evaluate the effect of regenerative therapy for the treatment of furcation involvements of mandibular molars with cone-beam computed tomography (CBCT).In the study, 38 furcation involvements of mandibular molars were included and randomly divided into two groups. The experimental group accepted guided tissue regeneration and bone graft therapy, and the control group only flap surgery. The clinical examination and CBCT examination were performed at baseline and 1 year post-surgery.The clinical and CBCT data of both groups were not statistically different at baseline (P0.05). At the end of 1 year post-surgery, except gingival recession, the clinical parameters of both groups were significantly improved (P0.001). The vertical and horizontal attachment gains of the experimental group were (3.20 ± 1.82) mm and (2.05 ± 1.27) mm, respectively, and significantly higher than the changes of the control group (P0.001). And at the end of 1 year post-surgery, the experimental group showed significantly higher bone gain at the vertical and horizontal directions compared with those of the control group: (2.82 ± 0.97) mm and (2.24 ± 0.92) mm, respectively (P0.001).With the limitation of this study, the effect of guided tissue regeneration surgery and bone graft therapy for the treatment of furcation involvements of mandibular molars is significantly better than that of the flap surgery. CBCT can reflect the horizontal and vertical bone changes of furcation area, which is more comprehensive than traditional periapicals.

To explore the clinical application of endoscope-assisted operative retrieval of large parotid stones as a minimally invasive alternative.From January 2010 to April 2013, 6 patients (male: 5, female: 1, age from 30-62 years, and median age: 49.5 years)suffering from recurred swelling of parotid gland due to sialoliths were treated by endoscope-assisted parotid surgery in Peking University School and Hospital of Stomatology. All of the patients underwent clinical, ultrasonographic and cone-beam CT (CBCT) examinations to get the detailed information of the number, location and size of stones, which was recorded in the medical records. endoscope-assisted parotid surgery was performed under general anesthesia in all the 6 cases after the failure of basket or forcep retrieval firstly. During the operation, sialoendoscope was used to locate the stone exactly and then the calculus was exposed through a pre-auricular approach and released by incising the duct. The postoperative complications were recorded and observed during the follow-up periods.Preoperative radiological examinations showed that all of the sialoliths were near the hilum of parotid gland ducts in the 6 cases, which were 5-9 mm in diameter. All of the stones were removed successfully by endoscope-assisted operative retrieval. The incisions healed smoothly in all the 6 cases. There were no cases of facial nerve weakness, infection or salivary fistula. After a mean follow-up of 19 months (ranging from 6-36 months), 5 patients remained asymptomatic and 1 patient had mild obstructed or infective symptoms. The final results were satisfied.It is suggested that endoscope-assisted operative retrieval is a viable minimally invasive alternative to remove the large or recalcitrant parotid stones with a high successful rate and low complications.

To develop a novel method for obtaining the clear visualization of the gingival profile by cone-beam computed tomography (CBCT) that consistently allows the measurements of gingival thickness and use it to explore the relationship between the gingival thickness and gingival biotype, and the gingival thickness and underlying alveolar bone thickness in the maxillary anterior region.In this study, 15 volunteers with healthy gingiva in the maxillary anterior teeth were involved, and a special preparation was done before CBCT scans including making impression with the contrast agent. The tissue biotypes were assessed clinically with the probe, The thickness of both gingiva and bone and the gingival thickness of the cemento-enamel junction (CEJ) were measured radiographically with cone-beam computed tomography scans. All data analyses were performed using SPSS 16.0.The CBCT image showed clear visualization of the gingival profile. The average gingival thickness of the CEJ was (1.22±0.32) mm. A correlation was observed between the tissue biotypes and the gingival thickness (r=0.449,P0.05). The labial gingival thickness was negative associated with the underlying bone thickness measured with CBCT in the maxillary anterior region (r=-0.31, P=0.021).A method was established for measuring gingival thickness based on cone-beam computed tomography. The gingival biotypes had a positive correlation with gingival thickness of the CEJ.

To evaluate the accuracy of measurement of II degree furcation involvements in molars of dry mandibles by cone-beam computed tomography (CBCT).Twenty molars with II degree furcation involvements in dry mandibles were examined directly and measured by CBCT. Eight parameters were selected to describe the exact appearance of each II degree furcation involvements, including vertical defect dimensions, horizontal defect dimensions and furcation entrance dimensions. The results were compared with the corresponding data obtained by probing and periapical radiograph.All furcation involvements could be correctly classified by CBCT. For 5 of 8 parameters, no significant difference was found between the data obtained by CBCT and probing measurements (P0.05). The distances from furcation entrance to alveolar crest, to bottom of bone pocket, and to the deepest site of horizontal bone defect measured by CBCT were less than those probed directly (P0.05), but the differences were less than 0.5 mm (0.21, 0.24, 0.35 mm, respectively). The localization of furcation entrance may cause the differences. Two out of 20 furcation involvements could not be detected on periapical radiographs, and only 2 of 8 parameters could be measured on periapical radiographs.CBCT could provide precise and detailed 3D images of II degree furcation involvements in vitro.

To investigate the condyle position in the fossa and obtain the reference ranges of Temporomandibular joint (TMJ) space of 50 healthy adults (100 joints) by using cone beam computed tomography (CBCT).Fifty healthy adults (100 joints) were selected and undergone CBCT examination in the intercuspal position. Five different methods of joint space measurement were used based on the joint sagittal middle layer of CBCT images and the results were analysed statistically.The reference ranges of TMJ space of CBCT images by using five measurement methods were obtained. The results of the linear measurement methods demonstrated that there were no significant differences between anterior and posterior spaces (Zor=0.99, P0.05),no significant differences between the two side joint spaces including anterior, posterior and superior spaces (tor=1.40, P0.05 ),and also no significant differences in ln (P/A) values between two side joints (tor=0.74, P0.05).All the results of the five measurement methods showed that the condyle was located in the center of the fossa with a variation in the healthy adults in intercuspal position.The CBCT image of the sagittal middle layer of the joint could show the joint space accurately and has an important value in the research related to the changes of TMJ space.

Osteoarthritic lesions of Temporomandibular joint(TMJ) were assessed by dental cone beam computed tomography(CBCT), and compared with conventional radiographic technology.The study was conducted retrospectively on 511 joints of 350 patients, who had undergone dental CBCT, panoramic radiography, transcranial projection and transpharygeal projection of TMJ. The results were compared and the accuracy with CBCT was assessed. The types of osseous condylar abnormalities were observed.(1) The occurrence of osteoarthritis in male and female were 59.04% and 69.66%, respectively, with no significant difference. (2) Compared with CBCT, panoramic radiography, transpharygeal projection examination showed no significant difference, with the accuracy being 90.64% and 94.10%, respectively; However, transcranial projection indicated a significant difference in comparison with CBCT and the accuracy was 86.97%. (3) A higher occurrence of osteoarthritic lesions of the condyle was sclerosis (39.86%). Bony proliferation or osteophyte (28.18%) and ill-defined cortical bone (18.90%) were followed.Cone beam CT, which reproduces multiple images including axial, coronal and sagittal planes of the joint, provides a complete radiographic investigation of the bony components of the TMJ. It is one of the best choices of imaging diagnosis of TMJ osteoarthritis. Panoramic radiography and transpharygeal projection examination are also good choices for showing osseous condylar abnormalities in the clinic, but transcranial projection examination is inferior.