Panoramic radiography: digital technology fosters efficiency.

Panoramic imaging continues to be a clinically popular tool in the diagnosis and assessment of dental patients. Digital technology improves the efficiency of the imaging system, may reduce overall costs and radiation risk, and aids in optimal interpretation of the image.

Accuracy and reliability of tooth and root lengths measured on cone-beam computed tomographs.

INTRODUCTION: In this study, we evaluated the accuracy and reliability of tooth-length and root-length measurements derived from cone-beam computed tomography (CBCT) volumetric data. METHODS: CBCT scans were made of 7 fresh porcine heads. The scans were made with an i-CAT machine (Imaging Sciences International, Hatfield, Pa) at 0.2, 0.3, and 0.4 mm voxel sizes. Two film-acquired periapical radiographs were also taken of selected incisors and premolars, 52 of which (28 premolars, 24 incisors) were included in this study. By using Dolphin imaging software (version 10.5, Dolphin Imaging Systems, Chatsworth, Calif), the CBCT scans were oriented twice for each tooth (ie, 2 trials) using the mesial, distal, labial, and lingual cementoenamel junctions as reference points. Root and tooth lengths were derived from these points and compared with actual measurements of the teeth made with digital calipers after all surrounding bone had been carefully removed. RESULTS: CBCT tooth-length and root-length measurements were not significantly different from the actual lengths; the mean differences were less than 0.3 mm. The periapical measurements significantly (P = 0.001) underestimated root lengths (mean difference, 2.58 mm) and overestimated tooth lengths (mean difference, 2.58 mm; P = 0.056). Mean differences between the 3 CBCT voxel sizes were all less than 0.25 mm. Within-trial method errors were almost 2 times greater for the periapical radiographs than for the CBCT scans. Between-trial method errors were greatest for the 0.4-mm CBCT scans, which were within 0.1 mm of the periapical radiograph method errors. The intraclass correlations for the periapical and CBCT measurements were all above 0.995. CONCLUSIONS: CBCT scans are at least as accurate and reliable as periapical radiographs for tooth-length and root-length determinations.

Reconstruction of canine mandibular bone defects using a bone transport reconstruction plate.

OBJECTIVES: Reconstruction of mandibular segmental bone defects is a challenging task. This study tests a new device used for reconstructing mandibular defects based on the principle of bone transport distraction osteogenesis. METHODS: Thirteen beagle dogs were divided into control and experimental groups. In all animals, a 3-cm defect was created on one side of the mandible. In 8 control animals, the defect was stabilized with a reconstruction plate without further reconstruction and the animals were killed 2 to 3 months after surgery. The remaining 5 animals were reconstructed with a bone transport reconstruction plate, comprising a reconstruction plate with attached intraoral transport unit, and were killed after 1 month of consolidation. RESULTS: Clinical evaluation, cone-beam CT densitometry, three-dimensional histomorphometry, and docking site histology revealed significant new bone formation within the defect in the distracted group. CONCLUSION: The physical dimensions and architectural parameters of the new bone were comparable to the contralateral normal bone. Bone union at the docking site remains a problem.

Mönckeberg medial calcinosis of the infraorbital arteries: a first case report.

Mönckeberg medial calcinosis describes calcifications affecting only the tunica media of medium-sized arteries. The entity is strongly associated with chronic kidney disease and diabetes mellitus. Radiographically, medial calcinosis presents as areas of linear calcifications in soft tissue; the linear calcifications are referred to as "tram tracks," "pipe stem," "rail tracking," or "tram line" when the affected vessel is viewed longitudinally. In oral and maxillofacial radiology, it is generally an incidental finding of the facial artery. In this article, we review the literature of Mönckeberg medial calcinosis and its clinical significance related to systemic diseases; we also present a case of Mönckeberg medial calcinosis of the head and neck that affects the facial arteries, internal carotid arteries, and infraorbital arteries. We believe this is the first presentation in the literature of Mönckeberg medial calcinosis visualized in the infraorbital arteries.

Can posterior teeth of patients be translated buccally, and does bone form on the buccal surface in response?

OBJECTIVE: To produce buccal translation and determine whether buccal bone forms on the cortical surfaces. MATERIALS AND METHODS: Eleven patients requiring maxillary first premolar extractions participated in this prospective, randomized, split-mouth study. Pre- and posttreatment records included models, photographs, and small field of view CBCT images. One randomly chosen maxillary first premolar was moved buccally with 50 g of force applied approximately at the tooth's center of resistance. The other premolar served as the control. Forces were re-activated every 3 weeks for approximately 9 weeks, after which the teeth were held in place for 3 weeks. Pre- and posttreatment records were analyzed and superimposed to evaluate changes in the dental-alveolar complex. RESULTS: There was significant (P < .05) movement of the experimental premolar with minimal buccal tipping (2.2°). Changes in maximum bone height were bimodal, with 6 patients showing 0.42 mm and 5 patients showing 8.3 mm of vertical bone loss. Buccal bone thickness 3 mm apical to the CEJ decreased 0.63 mm. Direct measurements and CBCT superimpositions showed that buccal bone over the roots grew 0.46 mm and 0.51 mm, respectively. CONCLUSIONS: It is possible to produce buccal bodily tooth movement with only limited amounts of tipping. Such movements are capable of producing buccal bone apposition, but there are potential limitations.

Analysis of the Size and Position of the Mental Foramen Using the CS 9000 Cone-beam Computed Tomographic Unit.

INTRODUCTION: The mental foramen (MF) houses vital neurovascular structures, thus making it an anatomic landmark of great importance for many dental procedures. Because the size and position of the MF can vary, proper planning is necessary beforehand to prepare the strategy of treatment. The purpose of this retrospective observational study was to determine and compare the size and position of the MF using the CS 9000 CBCT unit (Carestream Dental, Rochester, NY) to the findings from similar studies. METHODS: Tangential, axial, and coronal CBCT images of 106 patients were retrospectively evaluated to determine the size and position of the MF with respect to the mandibular second premolar apex and the cementoenamel junction. Distinguishing characteristics of sex, age, and race were evaluated. RESULTS: Regarding location, 53.7% of the MFs were located mesial, 45.3% distal, and 1% coincident to the apex of the mandibular second premolar. Males had a significantly greater coronal height and tangential height measurement than females. Black patients had a significantly greater distal horizontal distance from the cementoenamel junction than white patients. The mean width of the MF was 4.08 mm (axial) or 4.12 mm (tangential), whereas the mean height was 3.54 mm (tangential) or 3.55 mm (coronal). CONCLUSIONS: The present study shows that the size and position of the MF can be reliably measured using limited field of view CBCT technology. The findings are similar to previous studies when considering the averages and ranges of the measurements.

Advances in diagnostic imaging for pathologic conditions of the jaws.

Advances in dental and maxillofacial imaging are delineated along with the advantages and disadvantages of each imaging modality. The imaging modalities that are included are intraoral radiography, panoramic radiography, cone-beam computed tomography, multidetector computed tomography, magnetic resonance imaging, nuclear medicine, and ultrasound.

Inclusion of tobacco exposure as a predictive factor for decreased bone mineral content.

Tobacco exposure has been implicated as a risk factor for decreased bone density, which might result in osteoporosis. Cotinine, a metabolite of nicotine, is commonly used as a marker for tobacco exposure (active or passive). The objective of the present study was to compare tobacco exposure with other predictive factors for low bone mineral content (BMC), as determined by dual photon bone absorptiometry (DXA) in a national U.S. sample. Publicly available interview and clinical examination data from the Third National Health and Nutrition Examination Survey, 1988-1994 (NHANES-III) were used. Our data included 14,060 subjects from 19,528 randomly selected representative U.S. households. Clinical laboratory data included serum values for calcium and cotinine. BMC was assessed radiologically by DXA at five proximal femur sites. BMC values were adjusted for age, as well as height, weight, and bone area to correct for bone and body size. We used t tests to compare continuous variables and chi-square tests to explore associations between categorical variables. Multivariate regression models were developed for each gender with appropriate covariates. Intertrochanter BMC explained the most variation (highest R2) and was selected as the basis of the comparison. Serum cotinine had a significant inverse relationship to BMC in both males (p = .0069) and females (p = .0063). Serum cotinine, as a marker for tobacco exposure, is a statistically significant risk factor for decreased BMC in both genders and should be included in multivariate regression models to predict low BMC.

Macro design morphology of endosseous dental implants.

STATEMENT OF PROBLEM: The identification of dental implant bodies in patients without available records is a considerable problem due to increased patient mobility and to the large number of implant systems with different designs. PURPOSE: The purpose of this study was to document the designs of selected implants to help clinicians identify these implants from their radiographic images. MATERIAL AND METHODS: More than 50 implant manufacturers were contacted and asked to provide implants with dimensions as close as possible to 3.75 mm (diameter) x 10 mm (length). Forty-four implants were donated, separated into threaded and non-threaded categories, and further sorted into tapered and non-tapered categories. The implants were examined visually, and features on the entire circumference and length of each implant were recorded and categorized as coronal, midbody, or apical. RESULTS: A series of tables describe the 44 implants according to coronal, midbody, and apical features. CONCLUSION: The results of this project offer dentists basic knowledge of the design of selected dental implants. Such knowledge can aid the radiographic identification of these implants.

Radiographic identification of nonthreaded endosseous dental implants.

STATEMENT OF PROBLEM: The identification of dental implant bodies in patients without available records is a considerable problem due to increased patient mobility and to the large number of implant systems with different designs. PURPOSE: The purpose of this study was to document features that would help dentists identify non-threaded implant bodies from their radiographic images. MATERIAL AND METHODS: More than 50 implant manufacturers were contacted and asked to provide implants with dimensions as close as possible to 3.75 mm (diameter) x 10 mm (length). Forty-four implants were donated, 16 of which were identified as non-threaded. Radiographs were made of these implants at 0 degrees, 30 degrees, 60 degrees, and 90 degrees horizontal rotation combined with -20 degrees, -10 degrees, 0 degrees, +10 degrees, and +20 degrees vertical inclination relative to the radiographic beam and film. A total of 20 images per implant were taken and examined to identify consistent, unique features that would aid in implant identification. At a 20 degrees vertical inclination, vital features of implants were distorted enough to be deemed unrecognizable. Therefore, only those observations made from radiographs between -10 degrees and +10 degrees vertical inclination were used for implant identification purposes. RESULTS: All implants could be recognized from radiographs made between -10 degrees and +10 degrees vertical inclination. A series of tables and flowcharts describe the implants according to their identifying features. CONCLUSION: Information from this study should help dentists identify non-threaded endosseous implants from their radiographic images.

Radiographic identification of threaded endosseous dental implants.

STATEMENT OF PROBLEM: The identification of dental implant bodies in patients without available records is a considerable problem due to increased patient mobility and to the large number of implant systems with different designs. PURPOSE: The purpose of this study was to document features that would help dentists identify threaded implant bodies from their radiographic images. MATERIAL AND METHODS: More than 50 implant manufacturers were contacted and asked to provide implants with dimensions as close as possible to 3.75 mm (diameter) x 10 mm (length). Forty-four implants were donated, 28 of which were identified as threaded. Radiographs were made of these implants at 0 degrees, 30 degrees, 60 degrees, and 90 degrees horizontal rotation combined with -20 degrees, -10 degrees, 0 degrees, +10 degrees, and +20 degrees vertical inclination relative to the radiographic beam and film. A total of 20 images per implant were taken and examined to identify consistent, unique features that would aid in implant identification. At a 20 degrees vertical inclination, vital features of implants were distorted enough to be deemed unrecognizable. Therefore, only those observations made from radiographs between -10 degrees and +10 degrees vertical inclination were used for implant identification purposes. RESULTS: All implants could be recognized from radiographs made between -10 degrees and +10 degrees vertical inclination. A series of tables and flowcharts describe the implants according to their identifying features. CONCLUSION: Information from this study should help dentists identify threaded endosseous implants from their radiographic images.