PURPOSE: To evaluate the effect of deviation of mandibular positioning, by changing the mandibular plane inclination, on the measured height and width of mandible in spiral conventional tomography. MATERIALS AND METHODS: By means of the Scanora multifunctional unit, cross-sectional tomograms were taken from two human dried mandibles at the mandibular angulations: -15 degrees, -10 degrees, -5 degrees, and 0 degree. Twenty-eight sites in two dried mandibles were imaged. One examiner measured the bone heights and widths at selected sites on the images and the actual bone heights were recorded. RESULTS: The bone heights at the four mandibular inclinations overestimated real bone heights and the mean difference between actual heights and image heights on 0 degree was the smallest (P< 0.01). The bone widths on -15 degrees were narrowest and there were significant differences between bone widths measured at the four mandibular inclinations (P< 0.001). We found statistically significant differences between both bone heights and widths as measured according to the mandibular plane angle for the posterior region (P< 0.01). CONCLUSION: The use of different mandibular positioning may result in discrepancies in heights and widths when measured from the cross-sectional tomographic images. It is suggested that the mandibular positioning may play a significant role in the measurement of mandibular heights and widths.
Dental Implants ; Humans ; Mandible ; Radiography, Dental, Digital

PURPOSE: The purpose of this study was to investigate whether the fractal dimension of successive panoramic radiographs of bone after implant placement is useful in the characterization of structural change in alveolar bone. MATERIALS AND METHODS: Twelve subjects with thirty-five implants were retrospectively followed-up from one week to six months after implantation. Thirty-six panoramic radiographs from twelve patients were classified into 1 week, 1-2 months and 3-6 months after implantation and digitized. The windows of bone apical and mesial or distal to the implant were defined as periapical region of interest (ROI) and interdental ROI; the fractal dimension of the image was calculated. RESULTS: There was not a statistically significant difference in fractal dimensions during the period up to 6 months after implantation. The fractal dimensions were higher in 13 and 15 mm than 10 and 11.5 mm implant length at interdental ROIs in 3-6 months after implantation (P< 0.01). CONCLUSION: Longer fixtures showed the higher fractal dimension of bone around implant. This investigation needs further exploration with large numbers of implants for longer follow-up periods.
Dental Implants ; Follow-Up Studies ; Fractals* ; Humans ; Radiography, Panoramic ; Retrospective Studies

PURPOSE: The purpose of this study was to measure the buccal bone thickness and angulation of the maxillary incisors and to analyze the correlation between these parameters and the root position in the alveolar bone using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT images of 398 maxillary central and lateral incisors from 199 patients were retrospectively reviewed. The root position in the alveolar bone was classified as buccal, middle, or palatal, and the buccal type was further classified into subtypes I, II, and III. In addition, the buccolingual inclination of the tooth and buccal bone thickness were evaluated. RESULTS: A majority of the maxillary incisors were positioned more buccally within the alveolar bone, and only 2 lateral incisors (0.5%) were positioned more palatally. The angulation of buccal subtype III was the greatest and that of the middle type was the lowest. Most of the maxillary incisors exhibited a thin facial bone wall, and the lateral incisors had a significantly thinner buccal bone than the central incisors. The buccal bone of buccal subtypes II and III was significantly thinner than that of buccal subtype I. CONCLUSION: A majority of the maxillary incisor roots were positioned close to the buccal cortical plate and had a thin buccal bone wall. Significant relationships were observed between the root position in the alveolar bone, the angulation of the tooth in the alveolar bone, and buccal bone thickness. CBCT analyses of the buccal bone and sagittal root position are recommended for the selection of the appropriate treatment approach.
Cerebral Cortex ; Cone-Beam Computed Tomography* ; Facial Bones ; Humans ; Incisor* ; Maxilla ; Retrospective Studies ; Tooth ; Tooth Root

PURPOSE: The purpose of this study was to determine the prevalence of sinus opacification among dental paediatric patients. MATERIALS AND METHODS: Two hundred and eight Cone Beam Computed Tomography (CBCT) scans of dental patients under the age of 18 were reviewed for sinus opacification. Patients with any sinus-related signs or symptoms were excluded. RESULTS: The overall prevalence of sinus opacification was 48.1%. The ethmoid (28.4%) and maxillary (27.8%) sinuses were most frequently affected. There were no statistically significant differences for both age and gender. CONCLUSION: The high prevalence of sinus opacification in asymptomatic children emphasizes the necessity of clinical correlation.
Child ; Cone-Beam Computed Tomography ; Humans ; Prevalence ; Sinusitis

PURPOSE : This study compared panoramic radiography and cone beam computed tomography (CBCT) for evaluating the relationship between the maxillary sinus floor and the roots of maxillary molars. MATERIALS AND METHODS : Paired panoramic radiographs and CBCT images from 97 subjects were analysed. This analysis classified 388 maxillary molars according to their relationship to the maxillary sinus floor on panoramic radiograph and CBCT. Correlations between these two radiographic techniques were examined. RESULTS : Maxillary molar roots that were separate from the sinus floor showed the same classification in 100% of the cases when using these two imaging techniques. The corresponding percentage for such roots that were in contact with the sinus floor was 75%. When roots overlapped the maxillary sinus floor on panoramic radiographs, only 26.4% of maxillary first molars and 60.0% of second molars showed protrusion of roots into the sinus with CBCT. CONCLUSION : The results of the study suggest that roots projecting into the sinus on panoramic radiographs require a three-dimensional image in order to analyze the proximity of their apex to the sinus floor.
Cone-Beam Computed Tomography ; Floors and Floorcoverings ; Imaging, Three-Dimensional ; Maxillary Sinus ; Molar ; Radiography, Panoramic

PURPOSE: This study investigated the relationship between the roots of the maxillary molars and the maxillary sinus using cone beam computed tomography (CBCT), and measured the distances between the roots of the maxillary molars and the sinus floor as well as the thickness of the bone between the root and the alveolar cortical plate. MATERIALS AND METHODS: The study sample consisted of 83 patients with normally erupted bilateral maxillary first and second molars. A total of 332 maxillary molars were examined using CBCT images. The vertical relationship of each root with the maxillary sinus was classified into four types on CBCT cross-sectional images. The distance between the sinus floor and root and the bone thickness between the root and alveolar cortical plate were measured. RESULTS: In the buccal roots of the maxillary molars, a root protruding into the sinus occurred most frequently. A root projecting laterally along the sinus cavity was most common in the palatal roots of the maxillary first molars. The mesiobuccal roots of the maxillary second molar were closest to the sinus. The mesiobuccal roots of the first molars were closest to the cortical plate. CONCLUSION: The relationship between the roots of the maxillary molars and the sinus differed between the buccal and palatal roots. A root protruding into the sinus occurred more frequent in the buccal roots of the maxillary molars. The mesiobuccal root of the maxillary second molar was closest to the maxillary sinus floor and farthest from the alveolar cortical plate.
Bone and Bones ; Cone-Beam Computed Tomography ; Floors and Floorcoverings ; Humans ; Maxillary Sinus ; Molar

PURPOSE: To study the intra- and interobserver agreement of multidetector row computed tomography (MDCT) in interpretation of degenerative changes of the mandibular condyle. MATERIALS AND METHODS: Five observers independently evaluated one hundred temporomandibular joint MDCT images for signs of osteophytes, erosion, sclerosis and flattening. The intra- and interobserver agreements were calculated by using Kappa statistics. RESULTS: The intraobserver agreement was substantial for erosion (k=0.75), flattening (k=0.74) and sclerosis (k=0.72) and almost perfect for osteophytes (k=0.84). The interobserver agreement was fair for flattening (k=0.39), moderate for erosion (k=0.58) and sclerosis (k=0.48) and substantial for osteophytes (k=0.75). CONCLUSION: This study shows that we can expect good agreement for the presence of osteophytes, but not for flattening in the interpretation of MDCT images of the condyle.
Mandibular Condyle* ; Multidetector Computed Tomography ; Observer Variation ; Osteophyte ; Sclerosis ; Temporomandibular Joint ; Tomography, Spiral Computed

PURPOSE: The purpose of this study was to examine the patient- and treatment-related etiologic factors of external root resorption. MATERIALS AND METHODS: This study consisted of 163 patients who had completed orthodontic treatments and taken the pre- and post-treatment panoramic and lateral cephalometric radiographs. The length of tooth was measured from the tooth apex to the incisal edge or cusp tip on the panoramic radiograph. Overbite and overjet were measured from the pre- and post-treatment lateral cephalometric radiographs. The root resorption of each tooth and the factors of malocclusion were analyzed with an analysis of variance. A paired t test was performed to compare the mean amount of root resorption between male and female, between extraction and non-extraction cases, and between surgery and non-surgery groups. Correlation coefficients were measured to assess the relationship between the amount of root resorption and the age in which the orthodontic treatment started, the degree of changes in overbite and overjet, and the duration of treatment. RESULTS: Maxillary central incisor was the most resorbed tooth, followed by the maxillary lateral incisor, the mandibular central incisor, and the mandibular lateral incisor. The history of tooth extraction was significantly associated with the root resorption. The duration of orthodontic treatment was positively correlated with the amount of root resorption. CONCLUSION: These findings show that orthodontic treatment should be carefully performed in patients who need the treatment for a long period and with a pre-treatment extraction of teeth.
Female ; Humans ; Incisor ; Male ; Malocclusion ; Orthodontics ; Overbite ; Radiography, Panoramic ; Root Resorption ; Tooth ; Tooth Apex ; Tooth Extraction

PURPOSE: This study was performed to determine the prevalence of bifid mandibular condyles (BMCs) in asymptomatic and symptomatic temporomandibular joint (TMJ) subjects with no traumatic history, and to assess their impact on clinical and radiographic manifestations of TMJ. MATERIALS AND METHODS: A total of 3,046 asymptomatic and 4,378 symptomatic patients were included in the study. Cone-beam computed tomography (CBCT) images were reviewed for bifid condyles. T-tests were used to compare the frequency of BMCs when stratified by symptom, gender, and side. In BMC patients, the clinical features of pain and noise, osseous changes, and parasagittal positioning of the condyles were compared between the normally shaped condyle side and the BMC side using chi-squared tests. RESULTS: Fifteen (0.49%) asymptomatic and 22 (0.50%) symptomatic patients were found to have BMCs. Among the bilateral cases, the number of condyles were 19 (0.31%) and 25 (0.29%), respectively. No statistically significant differences were found between asymptomatic and symptomatic patients, between female and male patients, or between the right and left sides (p>0.05). Compared with the normally shaped condyle side, the BMC side showed no statistically significant differences in the distribution of pain and noise, parasagittal condylar position, or condylar osseous changes, with the exception of osteophytes. In the symptomatic group, osteophytes were found more frequently on the normally shaped condyle side than the BMC side (p<0.05). CONCLUSION: BMCs tended to be identified as an incidental finding. The presence of BMC would not lead to any TMJ symptoms or cause osseous changes.
Cone-Beam Computed Tomography ; Female ; Humans ; Incidental Findings ; Male ; Mandibular Condyle ; Noise ; Osteophyte ; Prevalence ; Temporomandibular Joint

PURPOSE: This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. MATERIALS AND METHODS: A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. RESULTS: The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. CONCLUSION: The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females.
Classification ; Crowns ; Female ; Humans ; Linear Models ; Male ; Molar, Third* ; Radiography, Panoramic ; Retrospective Studies ; Young Adult*