Objective To assess the reliability of low-dose(LD) cone-beam computed tomography (CBCT) protocols for radiographic assessment of third molars, including anatomical structures and related pathology, compared with standard-dose(SD) and high-dose(HD) protocols across three CBCT units. Materials and Methods This ex vivo study included 25 teeth from nine anonymized human skulls, each with one to four impacted third molars. Each tooth was scanned using HD, SD, and LD protocols on three CBCT units. Radiographic parameters were assessed by multiple observers, and inter- and intra-observer agreement was statistically analysed. Results Inter-observer agreement varied substantially across diagnostic parameters, CBCT units, and dose protocols, with κ values generally ranging from moderate to almost perfect agreement. Pronounced variability among observer pairs was observed for certain parameters within the same protocol and unit. No consistent reduction in reproducibility was observed when lowering the dose from HD to SD to LD. Intra-observer reproducibility was generally high. Conclusion Reproducibility in the assessment of third molars was primarily influenced by the diagnostic parameter and the observer rather than by CBCT dose level or unit. Lowering dose did not result in a consistent change in reproducibility. These findings indicate that LD protocols may provide sufficient reproducibility for third molar-related assessments.

Aim: To assess whether the use of centring rings for intraoral radiographic imaging reduces the number of retakes or the frequency and size of cone cuts in intraoral images performed by dental students. Material and Methods: Seventy-three dental students were randomly allocated to either a test or control group before training intraoral imaging on a phantom. Both groups used phosphor plate holders for periapical imaging of anterior and posterior teeth and for bitewings. Additionally, the test group used dedicated centring rings mounted to the holder (Kerr, Hawe, USA). After phantom training, the students performed intraoral imaging in 127 patients. Before patient examination, the number of planned periapical images and bitewings was recorded. After patient examination, the percentage of retakes was calculated in addition to the frequency and size of cone cuts. Differences between the two groups were tested with the Mann-Whitney U test (percentage of retakes and size of cone cuts) and chi-squared test (frequency of cone cuts). Results: The test group performed 920 intraoral images and the control 835. The percentage of bitewing retakes was significantly lower in the test group (p = 0.014), whereas there was no difference in periapical retakes (p = 0.37) between the groups. The frequency of cone cuts was significantly lower in the test group for both periapical images and bitewings (p < 0.001). The size of cone cuts was lower in the test group, although this was not significant (p > 0.20). Conclusion: In general, it seems beneficial to use centring rings for dental students when learning to perform intraoral imaging since the percentage of retakes as well as the frequency and size of cone cuts were reduced.

OBJECTIVES:To assess the incidence, distribution and morbidity of neurosensory disturbances of the inferior alveolar nerve (IAN), lingual nerve (LN), and buccal nerve (BN) after removal of mandibular third molars in the Danish population. STUDY DESIGN:Based on data from 2016-2021 from the Danish Dental Compensation system, relevant information regarding the quantity and quality of neurosensory disturbances after removal of a mandibular third molar was extracted. The incidence of neurosensory disturbance for each nerve branch was calculated. RESULTS:357 patients had a mandibular third molar removed and filed a permanent neurosensory disturbance to the Danish Dental Compensation. 187 disturbances were related to the IAN, 178 were related to the LN, and 113 were related to the BN. The overall incidence of confirmed neurosensory disturbances was 0.30% and specifically 0.15% for IAN, 0.15% for LN, and 0.09% for BN. The patient-reported degree of unpleasantness was not related to a specific nerve branch. CONCLUSION:The IAN and LN were equally involved when patients had a neurosensory disturbance after removal of a mandibular third molar with an incidence of 0.15% each. BN was less frequently involved. The neurosensory disturbances had a moderate to severe impact on the patient's personal and professional lives.

ObjectiveTo 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 designThe 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.ResultsSixteen 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.ConclusionsThe 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.

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.

Objective: To describe endodontic changes in an adult Danish population (C2;2009–2014–2019) and compare them with a similar cohort (C1;1997–2003–2008). Material and methods: A randomly selected cohort (C2) with three full-mouth radiographic examinations. The frequencies of teeth, apical periodontitis (AP), root filled teeth, and lost teeth in C2 were compared to a similar cohort (C1) using regression analyses; effect of age, cohort, and period was assessed. Results: C1 had 330 and C2, 170 participants (mean age, C1: 42.9; C2: 47.3 years, p < .001). The proportion of individuals with no AP was similar in C1 and C2 (p = .46). C2 had a higher proportion of individuals with no root filled teeth (p < .001) and no tooth loss (p = .02) than C1. The proportion of AP and root filled teeth increased with age in both cohorts. C2 had fewer root filled teeth and lost teeth, fewest lost teeth in the youngest age groups. Conclusions: In C2, the prevalence of teeth with AP and root fillings increased with age, and few teeth were lost. Change in proportion of AP was similar in two cohorts; fewer root filled teeth and lost teeth in C2. The proportion of lost teeth in C2 showed cohort effect for older age groups.

The aim of the study was to compare the frequency of root filled teeth and quality of root fillings (RFs) in two parallel, Danish cohorts each examined over 10 years and to evaluate factors associated with apical periodontitis (AP) and extraction of root filled teeth. Two randomly selected cohorts (C1, C2) from Aarhus (age: 20–64 years) were followed for approximately 10 years, with full-mouth radiographic surveys performed at 5-year intervals (C1: 1997–2003–2008; C2: 2009–2014–2019). Frequency of root filled teeth, quality of RFs and coronal restorations, periapical status and tooth extraction were registered. Logistic regression analyses compared C1 with C2 for baseline and follow-up periods and assessed variables associated with AP (PAI-based) and extraction of root filled teeth. C1 included 330 and C2, 170 individuals, mean age 42.9 and 47.3 years, respectively, who attended all three radiographic examinations. The relative frequency of root filled teeth was lower in C2 than C1 at baseline (C1: 4.7%, C2: 3.6%; p  < .001) and after 10 years (C1: 5.7%, C2: 4.2%; p  < .001). The relative frequency of new RFs was lower in C2 than in C1 ( p  = .02). C2 had fewer short/long RFs at baseline than C1; quality of new RFs or coronal restorations was similar in C1 and C2. The risk of tooth extraction ( p  = .93) and risk of AP ( p  = .37) at 10-year follow-up was similar between the two cohorts. For both C1 and C2, root filled teeth with AP at baseline had increased risk of having AP ( p  < .001) or having been extracted ( p  < .001) at follow-up. Risk of extraction was higher for root filled premolars ( p  = .01) and molars ( p  = .01) than anteriors. Risk of AP at follow-up was higher for root filled molars ( p  < .001). Furthermore, inadequate quality of RFs ( p  = .02) and coronal restorations ( p  = .04) increased the risk of AP at follow-up in C1 and C2. The frequency of root filled teeth and new RFs decreased and little to no change in new RFs' quality, AP, or tooth extraction was seen over time (1997–2019). Root filled molars and teeth with AP at baseline had increased risk of AP and extraction.

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. Chisquare 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. (Oral Surg Oral Med Oral Pathol Oral Radiol 2023;136:490-499)

AimThe aim of the study was to compare the frequency of root filled teeth and quality of root fillings (RFs) in two parallel, Danish cohorts each examined over 10 years and to evaluate factors associated with apical periodontitis (AP) and extraction of root filled teeth. MethodologyTwo randomly selected cohorts (C1, C2) from Aarhus (age: 20-64 years) were followed for approximately 10 years, with full-mouth radiographic surveys performed at 5-year intervals (C1: 1997-2003-2008; C2: 2009-2014-2019). Frequency of root filled teeth, quality of RFs and coronal restorations, periapical status and tooth extraction were registered. Logistic regression analyses compared C1 with C2 for baseline and follow-up periods and assessed variables associated with AP (PAI-based) and extraction of root filled teeth. ResultsC1 included 330 and C2, 170 individuals, mean age 42.9 and 47.3 years, respectively, who attended all three radiographic examinations. The relative frequency of root filled teeth was lower in C2 than C1 at baseline (C1: 4.7%, C2: 3.6%; p < .001) and after 10 years (C1: 5.7%, C2: 4.2%; p < .001). The relative frequency of new RFs was lower in C2 than in C1 (p = .02). C2 had fewer short/long RFs at baseline than C1; quality of new RFs or coronal restorations was similar in C1 and C2. The risk of tooth extraction (p = .93) and risk of AP (p = .37) at 10-year follow-up was similar between the two cohorts. For both C1 and C2, root filled teeth with AP at baseline had increased risk of having AP (p < .001) or having been extracted (p < .001) at follow-up. Risk of extraction was higher for root filled premolars (p = .01) and molars (p = .01) than anteriors. Risk of AP at follow-up was higher for root filled molars (p < .001). Furthermore, inadequate quality of RFs (p = .02) and coronal restorations (p = .04) increased the risk of AP at follow-up in C1 and C2. ConclusionsThe frequency of root filled teeth and new RFs decreased and little to no change in new RFs' quality, AP, or tooth extraction was seen over time (1997-2019). Root filled molars and teeth with AP at baseline had increased risk of AP and extraction.

AIM To compare measurements on images obtained by magnetic resonance imaging (MRI) and cone beam CT (CBCT) for height, width, and area in alveolar bone sites in human jaw specimens. MATERIAL AND METHODS Forty edentulous alveolar posterior sites in human cadaver specimens were imaged using CBCT scanners, and with zero-echo-time MRI (ZTE-MRI). Semi-automatic volume registration was performed to generate representative coronal sections of the sites related to implant planning. ZTE-MRI sections were also presented after grayscale inversion (INV MRI). Three observers measured bone height, bone width 5 mm from the alveolar crest, and bone area stretching from the width measurement to the top of the alveolar crest in the images. Interobserver agreement was assessed by intra-class correlation coefficients (ICC). The measurements were analyzed using two-way repeated measures ANOVA factoring observer and image type. RESULTS ICC was >0.95 for bone height, width, and bone area. No significant differences among observers (p = 0.14) or image type (p = 0.60) were found for bone height. For bone width, observer (p = 0.14) was not a significant factor, while ZTE-MRI produced width estimates that were significantly different and systematically smaller than CBCT-based estimates (p ≤ 0.001). Observer (p = 0.06) was not a significant factor regarding the bone area measurements, contrary to the imaging type where ZTE-MRI led to significantly smaller area estimates than CBCT (p ≤ 0.001). CONCLUSION Bone height measurements were essentially equivalent using CBCT and MRI. This was found regardless of grayscale choice for the MRI. However, ZTE-MRI resulted in smaller estimates of bone width and area.

Objectives To compare alveolar bone height and width measurements from zero-echo-time MRI (ZTE-MRI) and cone beam CT (CBCT), in human specimens. Material and methods Twenty posterior edentulous sites in human cadaver specimens were imaged with CBCT and ZTE-MRI. Bone height and width at 1, 3, 5, 7 and 9 mm from the top of the alveolar ridge was measured by two trained observers in cross-sections of a site where an implant was to be planned. Twenty percent of the sample was measured in duplicate to assess method error and intra-observer reproducibility (ICC). The differences between CBCT and ZTE-MRI measurements were compared (t-test). Results Inter- and intra-observer reproducibility was >0.90. The method error (average between observers) for bone height was 0.45 mm and 0.39 mm, and for bone width (average) was 0.52 mm and 0.80 mm (CBCT and ZTE-MRI, respectively). The majority of the bone measurement differences were statistically insignificant, except bone width measurements at 5 mm (p <= .05 for both observers). Mean measurement differences were not larger than the method error. Conclusion ZTE-MRI is not significantly different from CBCT when comparing measurements of alveolar bone height and width.

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.

Aim To compare the endodontic and periapical status of two similar adult Danish populations examined in 1997-1998 and 2007-2009, respectively. Methodology Two populations from Aarhus County, Denmark (age range: 20-64 years) were randomly selected using the Danish Civil Registration System. Full-mouth intraoral radiographs (14 periapical, 2 bitewing) of 616 individuals in 1997-1998 (C1: 16 018 teeth) and 398 individuals in 2007-2009 (C2: 10 668 teeth) were taken to ascertain the number of teeth, presence of root fillings (RFs) and apical periodontitis (AP) using the periapical index (PAI). T-tests with unequal variances were used to assess differences between C1 and C2 with respect to age and the number of teeth. Multivariable and multinomial logistic regression analyses were used to assess the effect of cohort, age and tooth type on the prevalence and relative frequency of RFs and AP. Results Mean age and mean number of teeth were higher in C2 than C1 (age; C1: 42.3 years, C2: 44.6 years; p = .003), (teeth; C1: 26.0, C2: 26.8; p < .001). The prevalence of root filled teeth was lower in C2 than C1 (C1: 51.8%, C2: 45.0%; p = .03); however, the prevalence of AP was similar (C1: 42.0%, C2: 45.0%). The relative frequency of root filled teeth was lower in C2 than C1 (C1: 4.8%, C2: 3.6%; p = .004), although the individuals were older in C2. The relative frequency of AP was similar in the two cohorts (C1: 3.3%, C2: 3.6%; p = .42). The relative frequency of AP in non-root filled teeth doubled from 0.9% in C1 to 1.8% in C2. C2 had higher PAI scores than C1 for root filled and non-root filled teeth, despite age correction (p <= .0007). Conclusions Two similar general Danish populations examined, respectively, in 1997-1998 and 2007-2009, were associated with a decreasing trend in the prevalence and relative frequency of RFs over the decade. There was no difference in relative frequency of AP in root filled teeth, but an increase in relative frequency of AP in non-root filled teeth. Further population-based studies including analysis of non-root filled teeth using the full-scale PAI and quality assessment of restorations are recommended.

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.

To compare the endodontic and periapical status of two similar adult Danish populations examined in 1997–1998 and 2007–2009, respectively. Two populations from Aarhus County, Denmark (age range: 20–64 years) were randomly selected using the Danish Civil Registration System. Full-mouth intraoral radiographs (14 periapical, 2 bitewing) of 616 individuals in 1997–1998 (C1: 16 018 teeth) and 398 individuals in 2007–2009 (C2: 10 668 teeth) were taken to ascertain the number of teeth, presence of root fillings (RFs) and apical periodontitis (AP) using the periapical index (PAI). T-tests with unequal variances were used to assess differences between C1 and C2 with respect to age and the number of teeth. Multivariable and multinomial logistic regression analyses were used to assess the effect of cohort, age and tooth type on the prevalence and relative frequency of RFs and AP. Mean age and mean number of teeth were higher in C2 than C1 (age; C1: 42.3 years, C2: 44.6 years; p  = .003), (teeth; C1: 26.0, C2: 26.8; p  < .001). The prevalence of root filled teeth was lower in C2 than C1 (C1: 51.8%, C2: 45.0%; p  = .03); however, the prevalence of AP was similar (C1: 42.0%, C2: 45.0%). The relative frequency of root filled teeth was lower in C2 than C1 (C1: 4.8%, C2: 3.6%; p  = .004), although the individuals were older in C2. The relative frequency of AP was similar in the two cohorts (C1: 3.3%, C2: 3.6%; p  = .42). The relative frequency of AP in non-root filled teeth doubled from 0.9% in C1 to 1.8% in C2. C2 had higher PAI scores than C1 for root filled and non-root filled teeth, despite age correction ( p  ≤ .0007). Two similar general Danish populations examined, respectively, in 1997–1998 and 2007–2009, were associated with a decreasing trend in the prevalence and relative frequency of RFs over the decade. There was no difference in relative frequency of AP in root filled teeth, but an increase in relative frequency of AP in non-root filled teeth. Further population-based studies including analysis of non-root filled teeth using the full-scale PAI and quality assessment of restorations are recommended.

AIM AND OBJECTIVE:This study assesses changes in the sella turcica area (STA) and location of the cephalometric point sella (S) on lateral cephalograms acquired by charge-coupled device (CCD)-based cephalostats with and without simulated patient head movements.MATERIALS AND METHODS:A real skull was placed on a robot, able to simulate four head movements (anteroposterior translation/lifting/nodding/lateral rotation) at three distances (0.75/1.5/3 mm) and two patterns (returning to 0.5 mm away from the start position/staying at maximum movement excursion). Two ProMax-2D cephalostats (Dimax-3, D-3 or Dimax-4, D-4), and an Orthophos-SL cephalostat (ORT) acquired cephalograms during the predetermined movements ("cases," 48 images/unit) and without movement ("controls," 24 images/unit). Three observers manually traced the contour of sella turcica and marked point sella using a computer mouse. STA was calculated in pixels2 by dedicated software based on the tracing. S was defined by its x and y coordinates recorded by the same software in pixels. Ten percent of the images were assessed twice. The difference between cases and controls (case minus control) for the STA and S (namely Diff-STA and Diff-S) was calculated and assessed through descriptive statistics.RESULTS:Inter- and intraobserver agreement ranged from moderate to good for STA and S. Diff-STA ranged from -42.5 to 12.9% (D-3), -15.3 to 9.6% (D-4), and -25.3 to 39.9% (ORT). Diff-S was represented up to 50% (D-3), 134% (D-4), and 103% (ORT) of the mean sella turcica diameter in control images.CONCLUSION:Simulated head movements caused significant distortion in lateral cephalograms acquired by CCD-based cephalostats, as seen from STA and S alterations, depending on the cephalostat.CLINICAL SIGNIFICANCE:Patient-related errors, including patient motion artifacts, are influential factors for the reliability of cephalometric tracing.

Abstract Background To evaluate whether buccal bone thickness (BBT), implant diameter, and abutment/crown material influence the accuracy of cone‐beam computed tomography (CBCT) to determine the buccal bone level at titanium implants. Methods Two implant beds (i.e., narrow and standard diameter) were prepared in each of 36 porcine bone blocks. The implant beds were positioned at a variable distance from the buccal bone surface; thus, resulting in three BBT groups (i.e., >0.5 to 1.0; >1.0 to 1.5; >1.5 to 2.0 mm). In half of the blocks, a buccal bone dehiscence of random extent (“depth”) was created and implants were mounted with different abutment/crown material (i.e., titanium abutments with a metal‐ceramic crown and zirconia abutments with an all‐ceramic zirconia crown). The distance from the implant shoulder to the buccal bone crest was measured on cross‐sectional CBCT images and compared with the direct measurements at the bone blocks. Results While abutment/crown material and implant diameter had no effect on the detection accuracy of the buccal bone level at dental implants in CBCT scans, BBT had a significant effect. Specifically, when BBT was ≤1.0 mm, a dehiscence was often diagnosed although not present, that is, the sensitivity was high (95.8%), but the specificity (12.5%) and the detection accuracy (54.2%) were low. Further, the average measurement error of the distance from the implant shoulder to the buccal bone crest was 1.6 mm. Conclusions Based on the present laboratory study, BBT has a major impact on the correct diagnosis of the buccal bone level at dental titanium implants in CBCT images; in cases where the buccal bone is ≤1 mm thick, detection of the buccal bone level is largely inaccurate.

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.