Low-dose, standard, and high-resolution cone beam computed tomography for alveolar bone measurements related to implant planning: An ex vivo study in human specimens.

AIM: To evaluate the performance of low-dose cone beam computed tomography (CBCT) protocols with regard to linear bone measurements in the posterior mandible for implant planning compared with higher dose protocols. MATERIALS AND METHODS: Forty-two edentulous posterior sites in human cadaveric mandibles were imaged in three CBCT scanners using three or four protocols with varying exposure parameters to achieve lower dose. Co-registration was performed to generate sagittal and cross-sectional image sections representative of the implant site. Three observers measured bone height, from the alveolar crest to the mandibular canal, and width, three mm from the top of the alveolar crest. Intra- and interobserver reproducibility were assessed for the cases rated as nonmeasurable as well as for completed measurements. The measurements were analyzed using paired t-tests for differences among the CBCT protocols and the frequency distribution of nonmeasurable cases with a Pearson Chi-square test. RESULTS: Reproducibility for registering nonmeasurable cases varied among observers; however, no consistent significant differences were found in the frequency distribution of these cases among observers, units, and protocols. Intraclass correlation coefficients (ICC) were >0.9 for all measurements of bone height and width. Mean differences of <0.5 mm were found regardless of protocol; however, one observer did in some cases produce larger differences. CONCLUSION: Linear bone measurements did not differ significantly and could be performed with excellent reliability, using low-dose CBCT protocols compared with standard and high-resolution ones. Varying approaches for rating nonmeasurable cases were found, indicating differences in diagnostic strategies related to implant planning among observers.

Long-term prognosis for teeth with external cervical resorption based on periapical images and cone beam CT: A clinical study.

AIM: To evaluate whether supplemental information from CBCT changed long-term prognosis for teeth with external cervical resorption (ECR) compared to periapical (PA) images. Furthermore, to assess predictive findings in PA images and evaluate which findings in CBCT affected the long-term prognosis of teeth with ECR. METHODOLOGY: One hundred and ninty-four patients, mean age 41.2, range 13-81, having 244 teeth with ECR were included. An initial long-term prognosis determined either good or poor was established based on intraoral images. Afterwards, the patients underwent CBCT, and final long-term prognosis was decided. From the PA images and CBCT, ECR using Heithersay's classification system, pulp involvement and extension of ECR was assessed. In CBCT, the number of surface lesion(s) was additionally assessed. Descriptive statistics evaluated changes in long-term prognosis after CBCT. Logistic regression analyses tested if findings in PA images and CBCT affected the long-term prognosis. RESULTS: Based on CBCT, out of 244 teeth the long-term prognosis was assessed to be poor for 173 (70.9%) teeth and good for 71 (29.1%) teeth. The long-term prognosis changed in 76 (31.1%) teeth after CBCT; 5 (2.0%) changed from poor to good, and 71 (29%) changed from good to poor long-term prognosis. In 81 (33.2%) teeth the H-class increased, and in 10 (4.1%) teeth the H-class decreased after assessing CBCT. In 70 (28.7%) teeth, there was a change from no pulp involvement to involvement of the pulp after CBCT; eight (3.3%) teeth changed in the opposite direction. H-class 2 and 4 in PA images significantly increased the probability for a change in long-term prognosis compared to an H-class 3 (p < .05). H-class 4, pulp involvement, ECR in the oral 1/3 of the root, and more than two surface lesions seen in CBCT significantly influenced a poor long-term prognosis (p < .05). CONCLUSIONS: Supplemental information from CBCT changed long-term prognosis in almost one third of teeth with ECR. In most cases, the long-term prognosis changed from good to poor. H-class 3 in PA images had a significant influence on change in long-term prognosis. Several findings in CBCT influenced a poor long-term prognosis.

Will supplemental cone beam computed tomography change the treatment plan of impacted maxillary canines based on 2D radiography? A prospective clinical study.

AIM: To evaluate the impact of cone beam computed tomography (CBCT) on treatment planning for impacted maxillary canines; secondly, to identify CBCT factors influencing a change in the treatment plan; and thirdly, to assess 2D radiographic factors that can aid in selecting appropriate candidates for CBCT. MATERIAL AND METHODS: Patients with impacted maxillary canines and an overlap of a neighboring tooth in 2D radiographs and the suspicion of root resorption were referred for CBCT examination. An initial treatment plan was based on 2D radiographs, and the final treatment plan was established after the CBCT examination. Logistic regression analyses and t-tests were performed to evaluate differences in radiographic findings between the groups with and without a change in treatment plan. RESULTS: The study prospectively included 125 impacted canines, and 43 (34.4%) of them had a change in treatment plan after the CBCT examination. The most common change was a modification in the direction of cantilever traction (n = 28; 22.4%), while the least common was the change in decision to remove/keep the canine (n = 4; 3.2%). The size of the alpha and lateral angles had a significant impact on the decision to change the treatment plan. Other radiographic findings did not influence a change in treatment plan. CONCLUSIONS: One-third of the canines had a change in treatment plan after supplemental CBCT examination. Canines with large alpha and lateral angles measured in the panoramic image were found to be significantly more likely to undergo changes in the initial direction of cantilever traction or changes to the canine extraction strategy following CBCT examination.

Use of artificial intelligence software in dental education: A study on assisted proximal caries assessment in bitewing radiographs.

INTRODUCTION: Teaching of dental caries diagnostics is an essential part of dental education. Diagnosing proximal caries is a challenging task, and automated systems applying artificial intelligence (AI) have been introduced to assist in this respect. Thus, the implementation of AI for teaching purposes may be considered. The aim of this study was to assess the impact of an AI software on students' ability to detect enamel-only proximal caries in bitewing radiographs (BWs) and to assess whether proximal tooth overlap interferes with caries detection. MATERIALS AND METHODS: The study included 74 dental students randomly allocated to either a test or control group. At two sessions, both groups assessed proximal enamel caries in BWs. At the first session, the test group registered caries in 25 BWs using AI software (AssistDent®) and the control group without using AI. One month later, both groups detected caries in another 25 BWs in a clinical setup without using the software. The student's registrations were compared with a reference standard. Positive agreement (caries) and negative agreement (no caries) were calculated, and t-tests were applied to assess whether the test and control groups performed differently. Moreover, t-tests were applied to test whether proximal overlap interfered with caries registration. RESULTS: At the first and second sessions, 56 and 52 tooth surfaces, respectively, were detected with enamel-only caries according to the reference standard. At session 1, no significant difference between the control (48%) and the test (42%) group was found for positive agreement (p = .08), whereas the negative agreement was higher for the test group (86% vs. 80%; p = .02). At session 2, there was no significant difference between the groups. The test group improved for positive agreement from session 1 to session 2 (p < .001), while the control group improved for negative agreement (p < .001). Thirty-eight per cent of the tooth surfaces overlapped, and the mean positive agreement and negative agreement were significantly lower for overlapping surfaces than non-overlapping surfaces (p < .001) in both groups. CONCLUSION: Training with the AI software did not impact on dental students' ability to detect proximal enamel caries in bitewing radiographs although the positive agreement improved over time. It was revealed that proximal tooth overlap interfered with caries detection.

Reliability of radiographic findings in large FOV CBCTs of mandibular third molars as basis for pre-operative patient information.

OBJECTIVE: The aim of this study was to assess the relation between radiographic findings in large field of view (FOV) cone beam computed tomography (CBCT) exams and clinical findings of mandibular third molars in relation to the pre-operative patient information. MATERIAL AND METHODS: Two hundred and nine mandibular third molars in 134 orthognathic patients examined with CBCT were removed. Three observers assessed tooth- and mandibular canal-related variables in CBCT images, and the findings were correlated to clinical findings during surgery for all observers: tooth angulation, number and morphology of roots and close relationship between the tooth and the mandibular canal. Moreover, positive (PPV) and negative (NPV) predictive values and positive (LR+) and negative (LR-) likelihood ratios were calculated for the canal-related variables. Inter- and intra-observer reproducibility was expressed as percentage accordance and kappa-statistics. RESULTS: Generally, there was high correlation between radiographic and clinical tooth-related variables. The opposite was true for the canal-related variables, since the PPV and LR + were low. The highest PPV and LR + were found when the mandibular canal was positioned between the roots of the third molar. CONCLUSIONS: Tooth-related findings in CBCT are reliable, whereas mandibular canal-related findings should not affect the information provided to the patient pre-operatively.

Comparing Clinical and Radiological Manifestations of Adolescent Idiopathic Condylar Resorption and Juvenile Idiopathic Arthritis in the Temporomandibular Joint.

PURPOSE: This cross-sectional study compared orofacial manifestations at the time of diagnosis in 2 temporomandibular joint (TMJ) conditions: adolescent idiopathic condylar resorption (ICR) and TMJ involvement from juvenile idiopathic arthritis (JIA). MATERIALS AND METHODS: This retrospective study included 19 JIAs, 19 ICRs, and 19 control patients, all treated at the Section of Orthodontics, Aarhus University Craniofacial Clinic, Denmark. From patient files, we retrieved radiological data from cone-beam computed tomographies along with information on symptoms and orofacial function at the time of diagnosis. Validated methodologies were used to evaluate TMJ and dentofacial morphology. RESULTS: We found no statistically significant intergroup differences in severity of deformation of TMJ structures (TMJ deformity) between JIA and ICR patients. However, the ICR group showed significantly greater signs of dentofacial deformity on 4 outcome variables: mandibular inclination, posterior/anterior lower face height ratio, mandibular sagittal position, and mandibular occlusal plane inclination. Significant intergroup differences in clinical presentation were seen in 5 of 20 variables. Thus, the JIA group reported significantly more symptoms of TMJ pain, TMJ morning stiffness, and TMJ pain on palpation during the clinical examination, whereas the ICR group reported significantly more TMJ clicking during function and had a higher proportion of patients with anterior open bite. CONCLUSIONS: Cone-beam computed tomography examination showed a similar degree of TMJ deformity in ICR and JIA patients at the time of diagnosis. ICR patients presented with a significantly higher degree of dentofacial deformity than JIA patients and healthy controls, which relates to the timing of the diagnosis. Arthralgia, TMJ morning stiffness, and TMJ palpitation pain were more common in JIA patients, whereas TMJ clicking during function and anterior open bites were more common in ICR patients.

Is thermography useful for assessment of postoperative inflammation after surgical removal of mandibular third molars when methylprednisolone is administered and how does it correlate with patients' perception of swelling?

PURPOSE: To assess the differences in facial skin temperature after mandibular third molar removal when patients received methylprednisolone and placebo, respectively and to assess the correlation between patient-reported swelling using a visual analog scale (VAS) and facial skin temperature measured using thermography. PATIENTS AND METHODS: The study involved patients with 2 mandibular third molars with an indication for removal. The patients received either methylprednisolone or placebo in a randomized, crossover study design. Thermograms and the swelling VAS score were recorded 2 days after surgery. The outcome variable was the temperature difference (Δt) between the operated and control sides. A 2-sample t test analyzed the difference in Δt between the first and second operations. Spearman's rank correlation analysis was used to assess the correlation between the swelling VAS scores and the Δt. RESULTS: A total of 124 patients (67 males, 57 females, mean age 25 years) had both mandibular third molars removed on 2 separate occasions. No difference in Δt was found when methylprednisolone and placebo were given (P = .07). In addition, the correlation between the swelling VAS score and Δt was 0.30 (P = .001) and 0.09 (P = .3) after the first and second operation, respectively. CONCLUSIONS: Thermography does not seem sensitive enough to detect differences in the inflammatory response when patients received methylprednisolone or placebo. The correlation between the Δt and patient-reported swelling was low (≤0.3).

Low-dose CBCT protocols in implant dentistry: a systematic review.

OBJECTIVE: To evaluate the state-of-the-art evidence for applying low-dose CBCT protocols in 3 stages of implant therapy (planning, insertion, and follow-up examination of peri-implantitis) and assess the overall body of evidence presented in the literature. STUDY DESIGN: The search was conducted in the MEDLINE/Pubmed and Scopus databases. Studies comparing low-dose CBCT protocols to a relevant reference standard in relation to any stage of implant therapy were included. Data extraction and quality assessment were performed for all included studies. RESULTS: Sixteen studies were included. Low-dose protocols were reported to result from reduction of the exposure parameters of kV, mA, resolution (through increased voxel size), exposure time, and scanning trajectory. The current literature suggests that low-dose CBCT protocols perform similarly in the 3 stages of implant therapy compared to higher resolution protocols regarding objective measurements, with adverse impacts mostly on subjective assessment of image quality. The results also suggest that CBCT-based bone measurements are similar to direct measurements, independent of the imaging protocol. Reduction in all parameters except kV seems feasible as the basis of low-dose CBCT protocols for implant therapy. CONCLUSIONS: The use of low-dose CBCT protocols does not impact objective image quality assessment in any stage of implant therapy. Clinical studies are needed to indicate if the reported results can be extrapolated to improve patient care in relation to the responsible use of ionizing radiation.

Treatment plan for maxillary third molars based on radiological findings varies among oral surgeons - a web-based "paper" clinic study.

OBJECTIVES: To evaluate variation in treatment plans and pathological findings related to maxillary second and third molars based on panoramic (PAN) images and cone beam CT (CBCT) among Danish and Dutch oral and maxillofacial surgeons. STUDY DESIGN: This web-based "paper" clinic contained 10 cases of impacted maxillary third molars comprising clinical information, PAN, and CBCT. Treatment plan and pathological findings were established based on clinical information and PAN, thereafter, based on CBCT by 28 surgeons. Options for treatment plan for third molars were no treatment, or tooth removal. Options for treatment plan for second molars were no treatment, tooth removal, or endodontic and/or filling therapy. The surgeons assessed external root resorption, marginal bone loss, and follicular space. RESULTS: A change in treatment plan between PAN and CBCT was registered between 0% and 43% of the surgeons among the cases. The surgeons did not agree completely on the treatment plan in any of the cases. Variation was present among the surgeons evaluating pathological findings. In several cases, severity of root resorption was rated worse in CBCT than in PAN. CONCLUSIONS: Variation in treatment plan and pathological findings was observed among surgeons. No correlation between change in pathological findings and change in treatment plan was found.

Efficiency of bupivacaine versus lidocaine and methylprednisolone versus placebo to reduce postoperative pain and swelling after surgical removal of mandibular third molars: a randomized, double-blinded, crossover clinical trial.

PURPOSE: To compare 4 treatment combinations to reduce postoperative pain and swelling after surgical removal of mandibular third molars. PATIENTS AND METHODS: Patients scheduled for bilateral mandibular third molar removal were randomized to 1 of 4 treatment groups in a double-blinded crossover design: 1) first operation: lidocaine and placebo, second operation: bupivacaine and methylprednisolone; 2) first operation: bupivacaine and methylprednisolone, second operation: lidocaine and placebo; 3) first operation: lidocaine and methylprednisolone, second operation: bupivacaine and placebo; 4) first operation: bupivacaine and placebo, second operation: lidocaine and methylprednisolone. Patient-reported pain and swelling were recorded using visual analog scales 2, 4, 6, 8, and 12 hours after surgery and daily during the first postoperative week. The treatment effects were estimated as contrasts between the average differences within the treatment groups and assessed by stratified t tests. RESULTS: A total of 126 patients (57 women and 69 men; mean age, 25.0 years) were included in the analysis. No significant interactions between local analgesia and methylprednisolone were observed. The administration of bupivacaine resulted in less postoperative pain up to 12 hours after surgery (P < .004) and more postoperative swelling 4 to 12 hours after surgery (P < .001) compared with lidocaine. The administration of methylprednisolone resulted in less postoperative pain 4 to 12 hours and 2 days after surgery (P < .05) and less postoperative swelling 6 and 12 hours and 1 to 3 days after surgery (P < .04) compared with placebo. CONCLUSIONS: Bupivacaine combined with methylprednisolone reduced the postoperative pain and swelling compared with the use of lidocaine and placebo, lidocaine and methylprednisolone, or bupivacaine and placebo.

Does cone beam CT change the treatment decision for maxillary second and third molars? A prospective study.

OBJECTIVES: To evaluate whether information from CBCT changes the treatment plan for maxillary second and third molars and to examine clinical and radiographic parameters with an impact on treatment decision. METHODS: This prospective study included 260 maxillary third molars with superimposition onto the second molar in panoramic images (170 patients; mean age 28 years, range 16-63). An initial treatment plan was based on clinical findings and panoramic images. After CBCT, a final treatment plan was decided. Treatment was undertaken based on the final treatment plan. Through logistic regression analyses, impact of clinical and radiographic parameters on change in treatment plan, removal of the third molar vs no treatment, and removal of the second vs third molar were evaluated. RESULTS: The treatment plan changed in 82 cases (32%). Sixteen cases (6%) changed from removal of the third molar to removal of the second molar. Regression analyses showed that severe resorption in the second molar was significantly related to a change in treatment plan. Removal of a third molar was decided in 180 cases and regression analyses identified that mesioangulation of the third molar, marginal bone loss, superficial resorption, and age were significantly related to removal of the third molar vs no treatment. Thirty second molars were removed, and regression analyses showed that severe resorption was significantly related to removal of the second molar instead of the third molar. CONCLUSIONS: Parameters such as resorption evaluated in CBCT can modify the treatment decision, resulting in removal of the second and/or the third molar.

Risk factors observed in 2-dimensional radiographs for permanent injury of the inferior alveolar nerve after removal of mandibular third molars: a case-control study.

OBJECTIVE: To assess whether differences exist in signs observed in 2D radiographs of mandibular third molars between a case group of patients with and a control group without permanent sensory disturbance of the inferior alveolar nerve (IAN) after removal. STUDY DESIGN: Three observers blinded to patient status assessed radiographs from the case group (n=162) and the control group (n=172). Two new signs, craniocaudal relation of the roots and the mandibular canal and position of the canal over the roots; and 4 "classic" signs, interruption of the white borders of the canal, darkening of the roots, narrowing of the canal lumen, and diversion of the canal over the roots were registered. Chi-square tests assessed differences in distribution of radiographic signs between the groups. Odds ratios expressed the association between radiographic signs and permanent sensory disturbance. Inter- and intraobserver reliability values were calculated. RESULTS: We found significantly more teeth with roots positioned inferiorly to the canal borders (P<0.001; OR 4.1-5.3) and with the canal superimposed over the upper or middle third of the roots (P<0.001; OR 2.6-3.9) in the case group than in the control group. Inter- and intraobserver reproducibility was excellent for roots inferior to the canal borders and fair to good for canal superimposition. CONCLUSIONS: Two radiographic signs are valid predictors of permanent sensory disturbance of the IAN in 2D radiographs.

Early detection of external cervical resorption in posterior teeth: a radiographic, cross-sectional study of an adolescent population.

OBJECTIVES: To establish the prevalence and severity of external cervical resorption (ECR) in posterior teeth observed in bitewing (BW) radiographs in an epidemiological study of a 17-year-old patient population from community dentistry. Furthermore, to assess the potential predisposing factors for ECR. METHODS: Posterior BWs from 5596 patients (2717 females, 2879 males; mean age 17.8 years) were assessed by three observers in order to detect ECR (using Heithersay's classification system, severity classes 1-4). When ECR was suspected, cone beam CT (CBCT) was offered to verify diagnosis. Prevalence was estimated based on ECR suspected in BWs and finally in CBCT. Possible predisposing factors (orthodontic treatment, trauma, and periodontal disease) were recorded and assessed for association with ECR. RESULTS: In 41 patients, ECR was suspected in BWs (suspected prevalence 0.73%). 32 patients accepted CBCT examination, of which eight were verified to have ECR (final prevalence 0.18%). In 24 patients, other disease entities and abnormal tooth morphology, that had mimicked ECR in BWs, excluded ECR in CBCT. ECR severity ranged from class 1-3 in BW and 2-4 in CBCT. All but one case had not been diagnosed by the patient's community dentist. No statistically significant association between predisposing factors and ECR was identified. CONCLUSIONS: ECR had low prevalence in this adolescent population, as observed in both BWs and CBCT. Still, early detection of ECR is important for treatment prognosis, and attention should be paid to this disease entity when assessing BWs obtained for other diagnostic purposes. CBCT may subsequently aid in verifying the disease.

Magnetic resonance imaging in the diagnosis of periodontal and periapical disease.

OBJECTIVES: Early pre-clinical inflammatory changes in periodontal and/or periapical lesions, which typically precede bone loss, are challenging to diagnose using ionizing-radiation-based imaging modalities. MRI provides relevant additional diagnostic information of inflammatory processes in soft and hard tissues. The aim of the present study is to undertake a systematic review of the literature on MRI in the diagnosis of periodontal and/or periapical disease. METHODS AND MATERIALS: The PubMed/MEDLINE and Scopus bibliographic databases were searched (2000-2021) using the search string: ("MRI" or "magnetic resonance imaging") and ("periodontitis" or "periodontal" or "apical pathology" or "endodontic pathology" or "periapical" or "furcation" or "intrabony"). The search was limited to studies published in English. The studies were assessed independently by three reviewers, focusing on the MRI sequences, imaging modalities (radiographs, cone beam CT (CBCT), and MRI), disease definition, assessed parameters, and outcome measurements. RESULTS: The search strategy yielded 34 studies, from which 13 were included. Overall, the findings of MRI were in agreement with CBCT. The studies showed that MRI provided diagnostic information of the hard and soft tissue components affected by periodontal and/or periapical disease with a fairly high sensitivity and specificity. However, the assessed parameters (e.g. MRI acquisition protocols, and disease definition) differed substantially. CONCLUSIONS: The included studies indicate that the use of MRI in the diagnosis of periodontal and/or periapical disease is feasible and promising. More studies are needed to define the accuracy of this non-ionizing-radiation-based diagnostic modality, in the assessment of periodontal and/or periapical lesions.

Should removal of lower third molars be included in the pre-graduate curriculum for dental students? An evaluation of post-operative complications after student operations.

OBJECTIVE: To evaluate guidelines for selection of lower third molars (M3) to be removed by dental students (DS) and to compare M3 surgery performed by oral surgeons (OS) and DSs with regard to operation time and post-operative complications. MATERIALS AND METHODS: Three hundred and thirteen patients with 313 lower M3 were assigned to be operated by either a DS or an OS, depending on the estimated difficulty of the surgery. During the post-operative week patients recorded pain (VAS) and other complications. Complications were also recorded objectively 1 week post-operatively. RESULTS: Operations performed by DSs lasted longer than operations performed by OSs (P < 0.001). There was no difference in immediate post-operative pain intensity between the two groups. There were no differences in patients' perception of bleeding, trismus, bad taste, use of analgesics, absence from work/school and seeking professional help between the two groups. Dry socket occurred more frequently though in patients in the DS group (P = 0.008). There was no difference in the frequency of objectively assessed swelling, paraesthesia or infection. CONCLUSIONS: When appropriately selected, patients operated by DSs did not perceive more immediate post-operative pain or complications than patients operated by OSs. However, dry socket and the risk of severe pain caused by this condition occurred more frequently in patients operated by DSs. The criteria used for selection of operations for DSs seem acceptable.

Impact of cone beam CT on diagnosis of external cervical resorption: the severity of resorption assessed in periapical radiographs and cone beam CT. A prospective clinical study.

OBJECTIVES: To compare the severity of external cervical resorption (ECR) observed in periapical (PA) images and cone beam CT (CBCT) using the Heithersay classification system and pulp involvement; and to assess inter- and intraobserver reproducibility for three observers. METHODS: CBCT examination was performed in 245 teeth (in 190 patients, mean age 40 years, range 12-82) with ECR diagnosed in PA images. Three observers scored the severity of ECR using the Heithersay classification system (severity class 1-4) and pulp involvement (yes/no) in both PA images and CBCT. Percentage concordance and κ-statistics described observer variation in PA images and CBCT for both inter- and intraobserver reproducibility. RESULTS: For all three observers, the ECR score was the same in the two modalities in more than half of cases (average 59%; obs1: 54%, obs2: 63%, obs3: 61%). However, in 38% (obs1: 44%, obs2: 33%, obs3: 36%) of the cases, the observers scored more severe ECR in CBCT than in PA images (p < 0.001). The ECR score changed to a less severe score in CBCT only in 3% (obs1: 1%, obs2: 4%, obs3: 4%). For pulp involvement, 14% (obs1: 7%, obs2: 20%, obs3: 15%) of the cases changed from "no" in PA images to "yes" in CBCT. In general, κ values were higher for CBCT than for PA images for both the Heithersay classification score and pulp involvement. CONCLUSIONS: ECR was generally scored as more severe in CBCT than PA images using the Heithersay classification and also more cases had pulp involvement in CBCT.

Initial radiological signs of dentofacial deformity in juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood and the temporomandibular joint (TMJ) is often involved. TMJ arthritis in growing individuals can cause deformation of facial skeleton (dentofacial deformity) and TMJ components (TMJ deformity). Treatment outcome hinges on early initiation of anti-inflammatory treatment and orthopaedic treatment with dental splints. The aim of the present study was to characterize the radiological signs of dentofacial deformity in patients with a JIA-induced need for orthopaedic treatment. We retrospectively studied 96 patients with JIA and 20 non-JIA controls to identify the initial radiological signs of JIA-induced dentofacial deformity leading to initiation of orthopaedic treatment. We found that initial radiological signs of dentofacial deformities were subtle and characterized by minor mandibular asymmetry and occlusal plane steepening. Radiological findings of TMJ deformity associated with initial dentofacial deformity were frequent and characterized by condylar articular surface flattening (OR 8.42), condylar subcortical cyst (OR 5.94), condylar surface erosion (OR 5.38) and condylar deviation in form (OR 25.39). Radiological signs of TMJ deformity were also documented in TMJs considered "healthy" during initial clinical and radiological examination. This study presents new knowledge of importance for early diagnosis of dentofacial deformity in JIA. Early diagnosis of dentofacial deformity is important as treatment outcome is greatly influenced by timely initiation.

Effect of computer-assisted-learning and simulation clinics on dental students' cognitive and performance skills: panoramic image errors related to patient's head position.

OBJECTIVES: To assess dental students' ability to recognize head positioning errors in panoramic (PAN) images after individual learning via computer-assisted-learning (CAL) and in a simulation clinic (SIM). Both cognitive skills and performance in patient examination were assessed. METHODS AND MATERIALS: 60 students (mean age 23.25 years) participated in lectures on the relation between PAN-image errors and patient's head position. Immediately after they took a test, based on which they were randomized to three groups: control (CON) group, CAL group, and SIM group (both CAL and training in a simulation clinic with a phantom). 4-5 weeks after intervention/no intervention, all students individually examined a patient with PAN-exposure. A blinded rater, not knowing group allocation, supervised patient exposure and assessed student's performance (correct/incorrect head position in three planes). 1-2 weeks after, the students scored positioning errors in 40 PAN-images. Differences in cognitive test scores between groups were evaluated by ANOVA and in patient examination by χ2 tests, and within-group differences by sign-tests. RESULTS: No statistically significant difference in cognitive test scores was seen between the SIM and CAL group, while the CON group scored lower (p < 0.003). In all groups, several students positioned the patient incorrectly in the Frankfort horizontal plane. All students performed well in the sagittal plane. Students in SIM group positioned the patient more correctly in the coronal plane. CONCLUSIONS: Training with CAL increased students' cognitive skills compared with a control group. Simulated patient exposure with a phantom increased to some extent their performance skills in examination of patients.

Cone beam CT and treatment decision of mandibular third molars: removal vs. coronectomy-a 3-year audit.

OBJECTIVES: To assess: (1) the workflow in the treatment decision process of mandibular third molars based on a panoramic image and CBCT and (2) the impact of radiographic markers in CBCT on the decision to perform coronectomy. METHODS: 1437 teeth in 917 patients (mean age 27.8 years, range 18-72) underwent clinical and panoramic examination. If there was an indication for removal of the tooth, and signs of a close relation to the inferior alveolar nerve were present in the panoramic image, a CBCT was performed. Treatment decision based on panoramic image and CBCT was calculated. Statistical analyses were performed to assess whether signs in CBCT had an impact on the treatment decision "coronectomy". Moreover, the actually operated teeth and post-operative sensory disturbances were assessed and discussed in relation to the radiographic method. RESULTS: Based on the panoramic image, in 462 cases it was decided not to treat, 553 were scheduled for surgery, and 422 referred for a CBCT examination. "No bony separation between the tooth and mandibular canal" seen in CBCT was the main factor influencing the decision to perform a coronectomy (odds ratio = 56.8, p < 0.001). 840 mandibular third molars had undergone surgical intervention, 152 had a coronectomy and 688 were fully removed. Six patients perceived a sensory disturbance of the inferior alveolar nerve: one permanent and five temporary. CONCLUSION: 29% of the examined cases were referred for a CBCT and of these, the majority were scheduled for coronectomy based on the sign "no bony separation between the tooth and mandibular canal" seen in CBCT.

Cone beam CT imaging of the mandibular third molar: a position paper prepared by the European Academy of DentoMaxilloFacial Radiology (EADMFR).

OBJECTIVES: Lack of evidence on the use of CBCT for management of mandibular third molars in Radiation Protection guideline no. 172 of the European Commission made the European Academy of DentoMaxilloFacial Radiology (EADMFR) decide to update the recommendations of the guideline. METHODS AND MATERIALS: A literature search was performed addressing the following questions: (1) does CBCT change the treatment of the patient?; (2) does CBCT reduce the number of post-operative sensory disturbances of the inferior alveolar nerve?; and (3) can CBCT predict the risk for a post-operative sensory disturbance of the inferior alveolar nerve? RESULTS:: Since the European Commission published the guideline in 2012 several high-evidence studies on the use of CBCT before removal of mandibular third molars have been conducted including five randomized controlled clinical trials and one meta-analysis. Present literature allows to propose recommendations with highest level of evidence. CONCLUSION: New and up-to-date evidence-based recommendations advocate that CBCT imaging of the mandibular third molar should not be applied as a routine method before removal of mandibular third molars and therefore, CBCT imaging should only be applied when the surgeon has a very specific clinical question in an individual patient case that cannot be answered by conventional (panoramic and/or intraoral) imaging.