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JADA Specialty Scan - Radiology
Radiology - A Quarterly Newsletter on Dental SpecialtiesJADA Specialty Scan

Importance of early diagnosis and management of impacted premaxillary supernumerary teeth

Early diagnosis and management of supernumerary teeth is critical to prevent complications and minimize the need for surgical and orthodontic treatment. In this retrospective study, the authors examined the radiographic features associated with impacted premaxillary supernumerary teeth, the effect on permanent incisors, and the types of orthodontic treatment used after extraction of these teeth. The findings are published in the December 2016 issue of Imaging Science in Dentistry.

The authors included 193 patients who underwent cone-beam computed tomography (CBCT) and panoramic radiography at Pusan National University Dental Hospital in South Korea between 2012 and 2013 before undergoing extraction of 241 impacted premaxillary supernumerary teeth (14 erupted teeth were excluded from the study). Participants included 144 boys and 49 girls, with a mean age of 7.41 years (range, 4 to 12 years). Sixty-eight percent of the children had 1 supernumerary tooth, 31% had 2 supernumerary teeth, and 0.5% had 3 supernumerary teeth.

CBCT scans were obtained with a PaX-Zenith 3-dimensional scanner (Vatech). Scanning parameters were set at 105 kilovolt (peak), 5.6 milliamperes, 24 seconds, 0.2 millimeters voxel size, and 12 × 9 cm field of view. Researchers used Ez3D Plus software (Vatech) to reconstruct CBCT volumetric data and a Proline XC machine (Planmeca) to obtain all panoramic radiographs.

The authors examined the CBCT and panoramic images to determine the number, location, sagittal position, orientation, and morphology of the impacted supernumerary teeth. They found that 64.7% of premaxillary supernumerary teeth were in the central incisor region and 76.8% were in a palatal position. An inverted orientation and conical shape also were most common.

Median diastema was the most common complication (17.8%), and it occurred most often in midline supernumerary teeth within the arch or in a transverse position. Other complications were delayed eruption of incisors (more often with vertically oriented than inverted supernumerary teeth) and displacement and rotation of adjacent teeth. Ten of the 14 odontoma-shaped teeth (71.4%) were associated with delayed eruption of permanent incisors.

The researchers examined orthodontic treatment after extraction of the impacted supernumerary teeth. Orthodontic traction was used in 7 of 14 cases (50%) of odontoma-shaped teeth, and orthodontic closure was used in 15 of 43 cases (34.9%) of median diastema. Orthodontic creation of space brought 32 maxillary incisors (13.3%) into a good position in the dental arch. However, in 186 cases (77.2%), permanent incisors erupted without orthodontic treatment after extraction of the supernumerary teeth.

The authors stressed the importance of early diagnosis of impacted supernumerary teeth to minimize the need for orthodontic and surgical treatment and prevent associated complications. If malalignment of adjacent permanent teeth is anticipated, early surgical removal is indicated.

Read the original article.


Consulting Editor: Laurie C. Carter, DDS, PhD
Past president, American Academy of Oral and Maxillofacial Radiology

Assessing TMJ osteoarthritis in patients with hand osteoarthritis

The osteoarthritis (OA) literature contains few studies pertaining to temporomandibular joint (TMJ) OA, which can lead to substantial joint pain, dysfunction, malocclusion, and reduced health-related quality of life. In this study, published online January 5 in Osteoarthritis and Cartilage, the authors explore self-reported TMJ-related symptoms, clinical examination findings, and cone-beam computed tomography (CBCT) results in a group of patients with hand OA.

The study consisted of 54 patients from a rheumatology outpatient clinic in Oslo, Norway, who, at follow-up, agreed to undergo CBCT examinations of their TMJs. Forty-eight of the 54 participants (88%) were female, and the mean age was 71.3 years. Researchers excluded patients from the study who had received a diagnosis of inflammatory joint disease.

CBCT was performed in the Department of Maxillofacial Radiology at the University of Oslo in Norway using a ProMax Mid 3D unit (Planmeca) (field of view, 200 × 600 millimeters; voltage, 90 kilovolts; tube current, 10 milliamperes; spatial resolution, 200 micrometers). The researchers reconstructed images in axial, oblique sagittal, and oblique coronal planes and analyzed them in a Sectra PACS viewer, IDS 5 version. Three experienced maxillofacial radiologists interpreted the images.

CBCT-defined OA was based on an evaluation of bony surfaces, including erosions, subcortical cysts, osteophytes, and sclerosis. The CBCT examinations revealed the presence of TMJ OA in 36 participants (67%), 17 of whom had bilateral OA. Researchers did not find TMJ OA in 10 of the 54 participants and categorized the remaining 8 participants as indeterminate for OA.

One dentist performed the clinical examinations and reported TMJ-related findings for 50 patients (93%). The most common findings were masticatory muscle pain at palpation and crepitus. The mean mouth opening was 51.2 mm; 1 participant had reduced mouth opening (39 mm). Twenty-four participants (44%) reported TMJ-related symptoms, with facial pain at rest and joint sounds being the most common. In all, 22 participants (41%) fulfilled the criteria for a clinical diagnosis of TMJ OA. Self-reported TMJ symptoms and clinical findings were more common in those with CBCT-defined TMJ OA than in those without OA or indeterminate for OA. Using CBCT as a reference, the sensitivity for clinical diagnosis of TMJ OA was low (0.42), but the specificity was high (0.93).

The researchers pointed out a few study limitations. The sample size was relatively small, and no control group was included. Longitudinal studies are needed to explore whether patients with hand OA are at an increased risk of developing TMJ OA.

TMJ OA was common in this group of elderly patients with hand OA, suggesting that it may be part of generalized OA. The authors emphasize the need to assess TMJ OA and related symptoms in patients with hand OA.

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Relationship between mandibular horizontal condylar angle and unilateral osteoarthritis degenerative changes

Temporomandibular joint (TMJ) osteoarthritis (OA) is an important subgroup of TMJ disorders. In this retrospective study, published in the April issue of Oral Surgery Oral Medicine Oral Pathology Oral Radiology, researchers investigate the relationship between the mandibular horizontal condylar angle and unilateral OA degenerative changes.

The study included 60 patients in the unilateral OA group (48 women, 12 men) and 43 patients in the control group (34 women, 9 men), with mean ages of 60 and 54 years, respectively. To ensure completion of TMJ development, participation was limited to patients 20 years and older.

The researchers reviewed cone-beam computed tomography (CBCT) reports to identify patients with unilateral moderate to severe OA changes, defined as condyles exhibiting severe erosive changes (> 1 millimeter), osteophyte formation (> 1 mm), or at least 2 of the following: osteophyte formation, erosion, subchondral cyst, flattening, and sclerosis. The authors considered contralateral joints with no or indeterminate OA changes to be unaffected. Patients whose CBCT images revealed no or indeterminate OA changes in either condyle made up the control group. Study patients received randomly assigned unique record identification numbers for condylar angle measurements to ensure that their TMJ diagnosis was not known during measurement of the condylar angles.

All CBCT images were obtained using a CB MercuRay unit (Hitachi), with 15 milliamperes, 120 kilovolt (peak), and a 9-inch field of view. Two senior radiologists in the School of Dentistry at the University of Washington in Seattle, completed all CBCT reports. They analyzed the CBCT images with Invivo5 dental software (Anatomage) and defined horizontal condylar angles in the axial plane as the angle between the condylar long axis and the coronal plane. The main observer measured the condylar angle in all joints 3 times on separate occasions at least 1 week apart. The investigators then used the mean of the 3 measurements for each joint for all analyses.

The study results revealed a significantly greater horizontal condylar angle in affected joints (mean [standard deviation {SD}] angle, 29.54 [10.54] degrees) than in contralateral, unaffected joints (mean [SD] angle, 22.51 [7.72] degrees). The angle of the affected joints was greater than that of unaffected joints in 47 of 60 patients (78%). The researchers found no statistically significant differences in the horizontal condylar angle between unaffected joints in patients with OA and those in control group patients.

The researchers found a statistically significant association between presence of flattening or erosion of the articular eminence within OA-affected joints and a larger condylar angle. Specifically, the mean condylar angle was 35.6 degrees for flattened eminences versus 29.1 degrees for eminences without flattening (P = .02). For eminences with erosion, the mean angle was 33.8 degrees, and for those without erosion, the mean angle was 29.0 degrees (P = .04).

The study findings revealed no statistically significant associations between individual condylar changes and condylar angles. Moreover, the authors found no association between condylar angle and presence of clinical symptoms or pain, range of motion, or crepitus.

One limitation of using condylar angle measurements as a marker for OA is that “measuring the condylar angle can be difficult when there is extensive erosion and osteophyte formation,” the authors explain. However, measuring the horizontal condylar angle may be a useful adjunct in assessing OA changes.

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CBCT to evaluate possible correlation between patient characteristics and maxillary sinus dimensions

Anatomic features of the maxillary sinus cavity play a critical role in treatment planning and surgical technique for dental implant placement. However, the relationship between sinus changes after tooth loss and patient characteristics is poorly understood. In an article published in the April issue of Implant Dentistry, researchers used cone-beam computed tomography (CBCT) to investigate the possible correlation between patient-dependent variables and dimensional variables of the maxillary sinus.

In this cross-sectional study, researchers obtained a random sample of 400 CBCT records from the Center for Radiological Diagnosis in Granada, Spain. Researchers categorized patients into 1 of 3 subgroups—dentate, partially edentulous, or completely edentulous—organized by age and sex. The final sample consisted of 394 patients (6 patients were excluded because of image artifacts or previous maxillary sinus floor elevation); 193 were male and 201 were female. The mean age was 47 years. Among all participants, 106 were dentate, 196 were partially edentulous, and 92 were completely edentulous.

All CBCT images were obtained using the Next Generation i-CAT unit (Imaging Sciences International), with the following settings: 120 kilovolt (peak), 5 milliamperes in complete rotatory mode, 16 × 18 cm field of view, 8.9 seconds’ acquisition time, and 0.3 millimeter voxel size. Using i-CAT Vision software (Imaging Sciences International), 1 calibrated oral and maxillofacial radiologist performed all measurements related to both sinuses in each patient.

The study findings showed that the older the patient, the smaller the distance between the most caudal point of the maxillary sinus floor and the middle meatus. In addition, the older the patient, the smaller the volume of the maxillary sinus. When comparing female and male patients, the authors found that in females, the distance from the most caudal point of the maxillary sinus to the meatus was shorter and sinus volume was smaller.

The researchers observed that edentulism was inversely correlated with the mediolateral distance. Bonferroni-corrected comparisons on the edentulism effect indicated that distances were larger in the dentate group than in the partially edentulous and completely edentulous groups, but no significant difference was found between the partially edentulous and completely edentulous groups.

Sinus volumes were also associated with edentulism status. Volumes were larger for dentate patients than for partially edentulous or completely edentulous patients. However, no significant difference was found between the partially edentulous and completely edentulous patients. The authors also noted that the height of septa in anterior locations was positively correlated with sinus volume.

The authors explain, “sinus anatomy determines surgical approach, modifications, potential complications, and strategies to correct and/or prevent them.” Thus, detailed clinical and radiographic evaluation of the posterior maxilla is imperative when planning tooth replacement with dental implants. CBCT scans are widely regarded as the criterion standard radiographic test in these clinical scenarios. Moreover, several studies have confirmed the accuracy of CBCT for 3-dimensional analysis, linear measurements, and volume quantification of the sinus.

The authors concluded that the dimensions of the maxillary sinus in this study were influenced by age and edentulism status. The data generated could be used to create preclinical digital models of this important anatomical structure.

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JADA+ Specialty Scans and JADA+ Scans

JADA+ Specialty Scans and JADA+ Scans are quarterly newsletters updating dentists on the latest research in selected specialties and disciplines in dentistry. ADA Publishing and the consulting editors from the represented specialties and disciplines aggregate and summarize research from previously published materials, each item attributed to its publication of origin. JADA+ Scan specialties and disciplines include endodontics, oral pathology, orthodontics, pediatric dentistry, periodontics, prosthodontics, radiology, cosmetic/esthetic and osseointegration. The ADA has engaged the specialty organizations in these areas as well as its own Science Institute and Division of Legal Affairs to assist with these newsletters. View past issues here.

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