Impact of acquisition volume on cone beam computed tomography imaging of marginal bone: an ex vivo study.

OBJECTIVE: The current study explores whether there is a clinically relevant distinction in the measurement of marginal bone loss when comparing high-dose (HD) versus low-dose (LD) cone beam computed tomography (CBCT) protocols in small and large acquisition volumes.  Material and Methods: CBCTs of four human cadaveric preparates were taken in HD and LD mode in two different fields of view 8 × 8 cm2 (LV) and 5 × 5 cm2 (SV). In total, 43 sites of 15 teeth were randomly chosen, and marginal bone loss was measured twice in all protocols at 43 sites of 15 teeth by one calibrated investigator. Bland-Altman plots and Lin's concordance correlation coefficient (CCC) were calculated to assess the extent of agreement of the measurements. Additionally, the rater scored the certainty in each of the measurements. RESULTS: For HD-CBCT CCC of measurements obtained using SV versus LV was 0.991. CCC of measurements obtained using SV versus LV of LD-CBCT was 0.963. Both CCC values indicated excellent agreement between the two volumes in both protocols.  CCC also indicated high intramodality correlation between HD-CBCT and LD-CBCT independent of the acquisition volume (0.963 - 0.992). Bland-Altman plots also indicated no substantial differences. Results of certainty scoring showed significant differences (p = 0.004 (LV), p < 0.001(SV)) between the LD and HD-CBCT. CONCLUSIONS: Accuracy of measurements of bone loss shows no clinical noticeable effects depending on the CBCT volume in this ex vivo study. There appears to be no relevant advantage of SV over LV, neither in HD-CBCT nor in LD-CBCT and additionally no relevant advantage of HD versus LD in visualizing marginal bone loss.

Changes in periodontal parameters of splinted versus non-splinted posterior teeth during ten years of supportive periodontal therapy - A retrospective evaluation.

OBJECTIVES: To compare periodontal parameters of splinted posterior teeth versus control teeth over ten years of supportive periodontal therapy (SPT) and to assess the survival rate of splints. MATERIAL AND METHODS: Retrospective data of 372 SPT-patients was screened for splints (composite/fiberglass-reinforced composite) in the posterior (molars/premolars) which were inserted at least ten years before due to increased tooth mobility. For each splinted tooth (test), a corresponding control tooth had to be present at the first SPT-session after splint insertion (T1). Data was assessed at T1 and ten years later (T2). Possible influencing covariates for splint survival (mobility degree/Eichner class) were tested by Cox regression. The change in clinical attachment level (ΔCAL), probing pocket depth (ΔPPD) and the testing of possible influencing covariates was analyzed by using mixed linear regression. RESULTS: Twenty-four patients (32 splints, 58 splinted teeth) were included. Ten test and two control teeth were lost. No differences were observed between ΔCAL and ΔPPD of test teeth compared to control teeth (ΔCAL -0.38 ± 1.90 vs. 0.20 ± 1.27 mm; ΔPPD -0.17 ± 1.18 vs. 0.10 ± 1.05 mm). Twenty-two splints fractured during the observation period (survival-rate: 31%). Mobility degree and Eichner class did not influence time until fracture. CONCLUSIONS: Splinting of periodontally compromised and mobile posterior teeth does not have any disadvantage regarding the clinical periodontal situation when regular SPT is applied. However, splint fractures occur very often. CLINICAL RELEVANCE: Splinting of posterior teeth is a treatment option in addition to active periodontal therapy when patients are disturbed by tooth mobility but splints have a high susceptibility to fracture.

Remote assessment of dental records by using intraoral scan-based digital three-dimensional models in an elderly patient population - an exploratory study.

AIM: To assess the agreement rates of dental records derived from intraoral scan-based digital three-dimensional models (3DM) and 3DM + panoramic radiographs (3DM+PAN-X) compared to clinical findings. MATERIALS AND METHODS: Based on the 3DM/3DM+PAN-X of 50 patients undergoing supportive periodontal therapy (SPT), ten remote raters (inexperienced in using IOS or 3DM) assessed for each site of the dental scheme (32 sites) whether a tooth was missing (M), filled (F), restoration- and caries-free (H), replaced by an implant (I) or decayed (D). Remote records were compared to the clinical reference record of each patient at tooth-level. The clinical records were assessed by an experienced dentist who supplemented the clinical findings with information from available radiographs and the patient records to define the clinical reference record. RESULTS: The agreement-rates for 3DM/3DM+PAN-X at tooth-level are: M: 93%/94%, F: 84%/88%, H: 92%/92%, I: 65%/96%, D: 29%/29%. The overall agreement-rate is 88% for the 3DM-based dental records (14093 of 16000 entries true) and 91% for 3DM+PAN-X (14499 of 16000 entries true). Using 3DM for dental record assessment, posterior teeth had higher odds of correct findings compared to anterior teeth (upper jaw OR=2.34, lower jaw OR=1.27). CONCLUSIONS: The remote detection of healthy, missing and filled teeth and implants by raters inexperienced in using IOS or 3DM shows a high agreement-rate with the clinical findings. The additional evaluation of PAN-X increased the agreement-rate significantly for implants. Thus, the remote assessment of dental records using 3DM+PAN-X has a high accuracy when applied in SPT-patients with low caries activity.

Dental imaging using an ultra-high resolution photon-counting CT system.

Clinical photon-counting CT (PCCT) offers a spatial resolution of about 200 µm and might allow for acquisitions close to conventional dental CBCTs. In this study, the capabilities of this new system in comparison to dental CBCTs shall be evaluated. All 8 apical osteolysis identified in CBCT were identified by both readers in all three PCCT scan protocols. Mean visibility scores showed statistical significant differences for root canals(p = 0.0001), periodontal space(p = 0.0090), cortical(p = 0.0003) and spongious bone(p = 0.0293) in favor of high and medium dose PCCT acquisitions. Overall, both devices showed excellent image quality of all structures assessed. Interrater-agreement showed high values for all protocols in all structures. Bland-Altman plots revealed a high concordance of both modalities with the reference measurements. In vitro, ultra-high resolution PCCT can reliably identify different diagnostic entities and structures relevant for dental diagnostics similar to conventional dental CBCT with similar radiation dose. Acquisitions of five cadaveric heads were performed in an experimental CT-system containing an ultra-high resolution PC detector (0.25 mm pixel size in isocenter) as well as in a dental CBCT scanner. Acquisitions were performed using dose levels of 8.5 mGy, 38.0 mGy and 66.5 mGy (CTDI16cm) in case of PCCT and of 8.94 mGy (CTDI16cm) in case of CBCT. The quality of delineation of hard tissues, root-canals, periodontal-space as well as apical osteolysis was assessed by two readers. Mean visibility scores and interrater-agreement (overall agreement (%)) were calculated. Vertical bone loss (bl) and thickness (bt) of the buccal bone lamina of 15 lower incisors were measured and compared to reference measurements by ore microscopy and clinical probing.

Remote assessment of DMFT and number of implants with intraoral digital photography in an elderly patient population - a comparative study.

OBJECTIVES: This comparative study aimed to evaluate intraoral digital photography (IODP) as assessment-tool for DMFT and number of implants (IMPL) compared to clinical diagnosis (CLIN) in an elderly population with high restorative status. Secondary research questions were whether an additional evaluation of panoramic radiographs (PAN-X) or raters' clinical experience influence the agreement. METHODS: Fifty patients (70.98±7.60 years) were enrolled for standardized CLIN and IODP. The clinical reference examiner and ten blinded raters evaluated the photographs without and with a PAN-X regarding DMFT and IMPL. CLIN were used as reference standard and differences to IODP and IODP-PAN-X findings were analysed descriptively. To assess intra-rater agreement, pairwise Gwet's AC1s of the three diagnostic methods CLIN, IODP and IODP+PAN-X were calculated. RESULTS: Compared to a DMFT of 22.10±3.75 (CLIN), blinded raters evaluated a DMFT of 21.54±3.40 (IODP) and 22.12±3.45 (IODP+PAN-X). Mean values for "Decayed" were 0.18±0.52 (CLIN), 0.45±0.46 (IODP) and 0.48±0.47 (IODP-PAN-X), while 11.02±5.97 (CLIN), 10.66±5.78 (IODP) and 10.93±5.91 (IODP+PAN-X) were determined for "Missing" and 10.90±5.61 (CLIN), 10.43±4.85 (IODP) and 10.71±5.11 (IODP+PAN-X) for "Filled". IMPL were 0.78±2.04 (CLIN), 0.58±1.43 (IODP), 0.78±2.04 (IODP+PAN-X). Gwet's AC1 using the mode of the blinded raters' assessment of "Decayed", "Missing" and IMPL compared to CLIN ranged from 0.81 to 0.89 (IODP) and 0.87 to 1.00 (IODP+PAN-X), while for "Filled" and DMFT they were 0.29 and 0.36 (IODP) as well as 0.33 and 0.36 (IODP+PAN-X), respectively. Clinical experience did not influence the agreement. CONCLUSIONS: Assessment of "Decayed", "Missing" and IMPL by IODP showed almost perfect agreement, whereas of "Filled" and DMFT revealed fair to moderate agreement with clinical findings. Additional PAN-X-evaluation increased agreement compared to IODP-diagnostics alone. IODP for the assessment of DMFT and IMPL might be a suitable method in large-scale epidemiological studies, considering high agreement in total values and miscellaneous agreement at patient-level.

Imaging furcation defects with low-dose cone beam computed tomography.

Different cone beam computed tomography (CBCT) protocols have shown promising results for imaging furcation defects. This study evaluates the suitability of low-dose (LD)-CBCT for this purpose. Fifty-nine furcation defects of nine upper and 16 lower molars in six human cadavers were measured by a high-dose (HD)-CBCT protocol, a LD-CBCT protocol, and a surgical protocol. HD-CBCT and LD-CBCT measurements were made twice by two investigators and were compared with the intrasurgical measurements, which served as the reference. Furcation defect volumes generated from HD-CBCT and LD-CBCT imaging were segmented by one rater. Cohen's kappa and intraclass correlation coefficient (ICC) values were calculated to determine intra- and interrater reliability. The level of significance was set at α = 0.05. In total, 59 furcation defects of nine upper and 16 lower human molars were assessed. Comparing CBCT furcation defect measurements with surgical measurements revealed a Cohen's kappa of 0.5975 (HD-and LD-CBCT), indicating moderate agreement. All furcation defects identified by HD-CBCT were also detected by LD-CBCT by both raters, resulting in a Cohen's kappa of 1. For interrater agreement, linear furcation defect measurements showed an ICC of 0.992 for HD-CBCT and 0.987 for LD-CBCT. The intrarater agreement was 0.994(r1)/0.992(r2) for HD-CBCT and 0.987(r1)/0.991(r2) for LD-CBCT. The intermodality agreement was 0.988(r1)/0.991(r2). Paired t-test showed no significant differences between HD-CBCT and LD-CBCT measurements. LD-CBCT is a precise and reliable method for detecting and measuring furcation defects in mandibular and maxillary molars in this experimental setting. It has the potential to improve treatment planning and treatment monitoring with a far lower radiation dose than conventional HD-CBCT.

Low-dose CBCT imaging of alveolar buccal bone adjacent to mandibular anterior teeth- a pilot study.

OBJECTIVES: Accurate description of buccal bone adjacent to mandibular anterior teeth is helpful for planning and monitoring periodontal and orthodontic treatment. Low-dose cone beam computed tomography (LD-CBCT) imaging has shown promising results for very small dental structures in animals. This study asserts that LD-CBCT is sufficiently accurate to measure buccal alveolar bone adjacent to human mandibular anterior teeth. MATERIALS AND METHODS: Buccal bone level adjacent to 16 mandibular anterior teeth from four human cadavers was measured radiographically using one high-dose (HD) CBCT protocol and two LD-CBCT protocols. The resulting radiographic measurements of buccal bone height (bl) and thickness (bt) were compared with reference probe and reflected-light microscopy measurements. Measurement medians and Bland-Altman plots were calculated, and a linear mixed model was used to compare raters and imaging modalities. RESULTS: All regression coefficients were approximately 0, indicating high interrater, intrarater, and intermodality agreement. No significant differences were found between reference measurements and CBCT protocols. The mean differences for bl measurements were 0.07 mm (rater 1 [r1]) and 0.12 mm (rater 2 [r2]) for HD-CBCT; 0.07 mm (r1) and 0.13 mm (r2) for LD-CBCT-1; and 0.02 mm (r1) and 0.01 mm (r2) for LD-CBCT-2. For bt measurements, mean differences were 0.02 mm (r1) and 0.02 mm (r2) for HD-CBCT; 0.01 mm (r1) and 0.01 mm (r2) for LD-CBCT-1; and 0.00 mm (r1) and 0.01 mm (r2) for LD-CBCT-2. CONCLUSIONS: Within the limitations of the present study, LD-CBCT seems to be a precise method for describing buccal bone and its thickness adjacent to mandibular anterior teeth in this experimental setting. CLINICAL RELEVANCE: For the first time, this study showed LD-CBCT produces excellent results and is a reliable modality for imaging buccal bone in vitro. If clinical studies confirm these results, LD-CBCT could enable better treatment planning and monitoring at a radiation dose that is far lower than that of conventional HD-CBCT but similar to that of panoramic views.

Prevalence of endo-perio lesions according to the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Disease in a university hospital.

OBJECTIVES: Teeth with combined endodontic-periodontal lesions (EPLs) have favorable to hopeless prognoses. The new classification system was developed by the World Workshop on the Classification of Periodontal and Peri-Implant Disease in 2017 and suitable epidemiologic data related to this new system are currently lacking. This study aims to contribute data about the prevalence of EPLs according to the new system. METHOD AND MATERIALS: A total of 1,008 panoramic views taken in 2019 were analyzed, recording the presence of an EPL and other periodontic parameters. Radiographs of bad quality and of the same person were excluded. Additionally, the EPLs' radiographic patterns were rated by two raters according to their shape (j-shaped vs cone-shaped). Descriptive statistical methods as well as t tests for continuous and chi-squared tests for categorical variables were used. RESULTS: Overall, 866 patients (with 18,963 teeth) were included. Prevalence of EPLs was 4.9% (n = 43) (patient-related)/0.4% (n = 71) (tooth-related). Mean age (62.3 years vs 51.5 years), mean maximal percentage of bone loss (60% vs 30%), and mean age-adjusted bone-loss index (1.0 vs 0.6) were considerably higher compared to patients without EPL. A total of 67 EPLs were found in patients with stage III/IV periodontitis and 4 in patients with stage II periodontitis. CONCLUSIONS: This is the first study showing prevalence of EPLs (4.9%/0.4%) according to the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Disease. Patients with EPLs have a substantially higher maximal percentage of bone loss and a higher age-adjusted bone-loss index at residual teeth, excluding teeth with EPLs. All patients have at least stage II periodontitis.

The impact of splinting timepoint of mobile mandibular incisors on the outcome of periodontal treatment-preliminary observations from a randomized clinical trial.

OBJECTIVES: To compare the outcome of periodontal parameters in mobile mandibular incisors which were splinted before or after full-mouth disinfection (FMD). MATERIALS AND METHODS: Thirty-four periodontitis patients with ≥ 1 mobile mandibular incisor (mobility degree II/III, clinical attachment loss (CAL) ≥ 5 mm, relative bone loss ≥ 50%) were randomly allocated to group A or B. Patients received periodontal treatment (PT) including splinting of teeth 33-43 before (A) or after FMD (B). Patient (age/sex/smoking status/systemic diseases/number of teeth) and tooth-related parameters (mean probing pocket depth (PPD)/CAL/oral hygiene indices; for the overall dentition and region 33-43) were assessed prior to PT and 12 months after FMD by a blinded examiner. Therapy-related information was added (group/antibiotic therapy/surgical intervention). RESULTS: Twenty-six patients (A: 12; B:14) were re-examined. Two patients of group B did not need splinting after FMD because of reduction in mobility after FMD. Regression analysis revealed a positive association of antibiotic therapy with CAL_overall, PPD_overall, and PPD_33-43 (p ≤ 0.01). There is a trend toward a higher reduction of periodontal parameters at teeth 33-43 in group A (PPD_33-43: - 0.91 vs. - 0.27 mm; CAL_33-43: - 1.02 vs. - 0.47 mm). CONCLUSIONS: Teeth splinted before or after FMD show a significant improvement in periodontal parameters 12 months after FMD. Splinting after FMD offered the option to detect reduction in mobility. CLINICAL RELEVANCE: Despite a higher, but not statistically significant, improvement in periodontal parameters on teeth splinted before FMD, the results do not indicate which timepoint of splinting is more beneficial. The decision for the therapeutic procedure should therefore be made individually.

Ex-vivo imaging of buccal and oral periodontal bone with low-dose CBCT in porcine jaws.

OBJECTIVES: New CBCT devices have been developed which can provide "low-dose CBCTs (LD-CBCT)". Aim of this study is to investigate the suitability of LD-CBCT for measurement of alveolar buccal/oral bone. METHODS AND MATERIALS: Vestibular and oral bone loss of the teeth of seven porcine mandibles free of soft tissues were investigated by Micro-CT and three CBCT-modes: high-dose (HD), standard-dose (SD) and low-dose (LD). Radiographic measurements of bone loss (bl) and vestibular and oral bone thickness (bt) were made by two raters at 69 sites. Measurement means and differences, Intraclass correlation (ICC) and Bland-Altman plots were calculated. RESULTS: ICCs between raters(r) concerning bl were 0.954 for HD, 0.949 for SD and 0.945 for LD; concerning bt they were 0.872 for HD, 0.845 for SD and 0.783 for LD. Means of differences of bt measurements were -0.01 mm(r1)/0.00 mm(r2) for HD, 0.04 mm(r1)/0.02 mm(r2) for SD and 0.02 mm(r1)/0.04 mm(r2) for LD; for bl measurements they were 0.06 mm(r1)/0.05 mm(r2) for HD, -0.01 mm(r1)/0.13 mm(r2) for SD and 0.07 mm(r1)/0.16 mm(r2) for LD.Linear regression indicates no noticeable differences between methods and the raters with respect to bl and bt. CONCLUSIONS: Relating to the CBCT-device used in this study, LD-CBCT is a promising method to detect and describe buccal and oral periodontal bl and bt. Further studies with human anatomic structures must confirm these results.

The impact of splinting mobile mandibular incisors on Oral Health-Related Quality of Life-Preliminary observations from a randomized clinical trial.

AIM: To compare the Oral Health-Related Quality of Life (OHRQoL) of patients with mobile mandibular incisors before and after full-mouth disinfection (FMD) with and without splinting. MATERIAL AND METHODS: Thirty-four periodontitis patients with ≥1 mobile mandibular incisor (degree II/III) were randomly allocated to the test or control group. All patients received FMD and the test group additional splinting of teeth 33-43. OHRQoL was assessed before (BL) and 3 months after FMD (RE) using the Oral Health Impact Profile (OHIP)-14. Data were compared within and between the groups (Wilcoxon test/Mann-Whitney U test). RESULTS: Twenty-eight patients (13 test group/15 control group) were re-evaluated. FMD led to a reduction of the mean probing pocket depth (PPD; in mm) (test group: BL-PPD 3.89 ± 1.03, RE-PPD 2.82 ± 0.53; control group: BL-PPD 3.58 ± 0.66, RE-PPD 2.77 ± 0.59; each p ≤ .001), the mean clinical attachment level (CAL; in mm) (test group: BL-CAL 5.22 ± 1.38, RE-CAL 4.79 ± 0.85; control group: BL-CAL 4.58 ± 1.10, RE-CAL 4.41 ± 0.96; each p ≤ .05), and the mean OHIP-14 summary scores (test group: BL-OHIP 21.7 ± 11.06, RE-OHIP 9.9 ± 8.96, p = .0046; control group: BL-OHIP 16.8 ± 8.27, RE-OHIP 11.7 ± 8.55; p = .0217). The reduction of the OHIP-G14 scores was considerably higher in the test group but statistically not significant (p = .080). CONCLUSIONS: The results show a positive impact of non-surgical periodontal treatment on OHRQoL and a possible tendency for further improvement by splinting mobile mandibular incisors.

Effect of endodontic treatment on periodontal healing of grade 3 endo-periodontal lesions without root damage in periodontally compromised patients-a retrospective pilot study.

OBJECTIVES: There is little evidence about the effect of different treatment protocols for grade 3 endo-periodontal lesions without root damage in patients with periodontitis according to the new classification of periodontal disease. The aim of this study is to evaluate the impact of endodontic treatment on the achievement of periodontal healing. MATERIALS AND METHODS: Teeth with the initial diagnosis endo-periodontal lesion without root damage grade 3, treated with a standardized endodontic treatment protocol, were included in this study. A retrospective analysis was performed to assess the impact on periodontal healing by evaluating probing pocket depth (PPD), clinical attachment gain (CAL), and periapical index score (PAI). RESULTS: Nineteen teeth and 13 patients were included. A mean reduction of 3.19 ± 3.41 mm in PPD was recorded. The mean CAL gain was 2.33± 3.75 mm. Five teeth (45.4%) showed an improvement of PAI and were classified as treatment success. CONCLUSIONS: The results failed to show a highly predictable treatment outcome for endo-periodontal lesion grade 3 without root damage in patients with periodontitis. However, endodontic therapy alone resulted in treatment success for some of the teeth, which would otherwise have had a poor prognosis. CLINICAL RELEVANCE: Endo-periodontal lesions can often be challenging for dentists in daily clinical practice. To date, there is not much evidence for practitioners to rely on. Therefore, this study aims to strengthen the evidence for the management and treatment of endo-periodontal lesions. Although the outcome is not highly predictable yet, teeth with the initial diagnosis endo-periodontal lesion without root damage grade 3 can benefit from an endodontic treatment.

Adherence to long-term supportive periodontal therapy in groups with different periodontal risk profiles.

AIM: To examine changes of the periodontal risk assessment (PRA) of patients during long-term supportive periodontal therapy (SPT) and to examine the adherence to recommended visit intervals. MATERIAL AND METHODS: Retrospective data from 372 SPT patients were evaluated before and after active periodontal therapy (APT) and at least 5 years later. After APT and regularly during SPT, PRA was performed for all included patients (low-risk/moderate-risk/high-risk profile) and they were advised to adhere to 3/6-/or 12-month intervals accordingly. The adherence (fully/partially/insufficiently/non-adherent) to SPT intervals was assessed retrospectively. RESULTS: Initially, 38 patients had a low-risk, 217 a moderate-risk and 94 a high-risk profile. Five years after APT, 55.3% of the low-risk, 71.9% of the moderate-risk and 54.3% of the high-risk patients had not changed their initial risk. 19.5% of the moderate-risk group shifted to "high-risk" and 8.6% to "low-risk". 66% of low-risk, 34% of moderate-risk and 13% of high-risk patients fully adhered to SPT. The portion of non-adherent patients was the highest within the high-risk group (18%-43%). The level of adherence was associated with number of lost teeth and mean PPD (p < .05). CONCLUSIONS: Risk profiles can change during SPT. A high level of adherence to SPT intervals based on PRA positively influences the periodontal status.

Ex vivo comparison of CBCT and digital periapical radiographs for the quantitative assessment of periodontal defects.

OBJECTIVES: Accurate imaging is essential for effective treatment planning in periodontology. The aim of this ex vivo study was to investigate the accuracy of cone beam computed tomography (CBCT) and digital periapical radiographs (PA) in imaging periodontal defects. Hypotheses are: 1. That CBCT is a more accurate method than PA concerning vertical measurements of periodontal bone defects2. That CBCT itself is an accurate method to describe vertical periodontal bone loss MATERIAL AND METHODS: In this study, 117 periodontal defects from 10 human cadavers were investigated radiographically by CBCT and PA by one calibrated observer. Afterwards the vertical bone loss was measured with a periodontal probe by the same calibrated observer. Differences between radiographic and clinical measurements were calculated and analyzed. Bland-Altmann plots including 95% limits of agreement were calculated. RESULTS: The 95% limits of agreement ranged from 3.29 to -3.27 mm between clinical measurements and measurements in PAs, and from 2.13 to -1.97 mm in CBCTs. The mean difference between clinical and radiographic measurements was 0.0009 mm for PA and 0.0835 mm for CBCT. CONCLUSIONS: When comparing the clinical measurements, CBCT had a higher agreement and less deviations than PAs, and CBCT seems to be an accurate method to describe vertical periodontal bone loss. CLINICAL RELEVANCE: Accurate description of defects is helpful for accurate treatment planning.

Dental magnetic resonance imaging for periodontal indication - a new approach of imaging residual periodontal bone support.

OBJECTIVE: The standard imaging techniques used in dentistry consist of two-dimensional radiographic techniques like intraoral periapical (PA) radiographs, bitewings or extraoral panoramic X-rays. Three-dimensional methods, such as cone beam computed tomography (CBCT), are not standard procedures. In several fields of dentistry, such as oral surgery or implantology, dental magnetic resonance imaging (DMRI), a technique without radiation exposure, has already been introduced as a new promising diagnostic tool. The aim of this study was to compare the agreement of DMRI and PA radiographs in measuring residual periodontal bone support. MATERIAL AND METHODS: In this study, the residual periodontal bone support of 21 teeth was investigated and compared with DMRI and PA radiographs by two independent raters. Intra-class correlation coefficients (ICCs) were calculated using the software R to identify the intra-rater and inter-rater agreement of the two modalities. Bland-Altman plots were created to directly compare the two methods. RESULTS: Overall, all calculated ICC values showed an excellent intra-rater and inter-rater agreement (>0.9) for DMRI, as well as PA radiographs. Bland-Altman analysis also showed a strong agreement between both diagnostic methods in this study. CONCLUSIONS: In conclusion, there was a strong agreement between DMRI and PA. Thus, DMRI proved to be a comparable method to PA radiographs for evaluating the proportion of residual periodontal bone support.

Peripheral neuropathy: detection with diffusion-tensor imaging.

PURPOSE: To investigate the ability of diffusion-tensor imaging (DTI) and T2 to help detect the mildest nerve lesion conceivable, that is, subclinical ulnar neuropathy at the elbow. MATERIALS AND METHODS: This prospective study was approved by the institutional ethics board. Written informed consent was obtained from all participants. Magnetic resonance neurography was performed at 3.0 T by using proton density- and T2-weighted relaxometry and DTI on elbows in 30 healthy subjects without clinical evidence of neuropathy. Quantitative analysis of ulnar nerve T2 and fractional anisotropy (FA) was performed, and T2 and FA values were correlated to electrical nerve conduction velocities (NCVs) with Pearson correlation analysis. Additional qualitative assessment of T2-weighted and FA images was performed by two readers, and sensitivity and specificity were calculated. RESULTS: Ten of the 30 subjects (33%) had NCV slowing across the elbow segment. Compared with subjects without NCV slowing, subjects with slowing had decreased FA values (0.51 ± 0.09 vs 0.41 ± 0.07, respectively; P = .006) and increased T2 values (64.2 msec ± 10.9 vs 76.2 msec ± 13.7, respectively; P = .01) in the proximal ulnar sulcus. FA values showed a significant correlation (P = .01) with NCV slowing over the sulcus as an electrophysiologic indicator of myelin sheath damage. Qualitative assessment of FA maps and T2-weighted images helped identify subjects with conduction slowing with a sensitivity of 80% and 55%, respectively, and a specificity of 83% and 63%. CONCLUSION: FA maps can accurately depict even mild peripheral neuropathy and perform better than the current standard of reference, T2-weighted images. DTI may therefore add diagnostic value as a highly sensitive technique for the detection of peripheral neuropathy.

MR neurography in ulnar neuropathy as surrogate parameter for the presence of disseminated neuropathy.

PURPOSE: Patients with ulnar neuropathy of unclear etiology occasionally present with lesion extension from elbow to upper arm level on MRI. This study investigated whether MRI thereby distinguishes multifocal neuropathy from focal-compressive neuropathy at the elbow. METHODS: This prospective study was approved by the institutional ethics committee and written informed consent was obtained from all participants. 122 patients with ulnar mononeuropathy of undetermined localization and etiology by clinical and electrophysiological examination were assessed by MRI at upper arm and elbow level using T2-weighted fat-saturated sequences at 3T. Twenty-one patients were identified with proximal ulnar nerve lesions and evaluated for findings suggestive of disseminated neuropathy (i) subclinical lesions in other nerves, (ii) unfavorable outcome after previous decompressive elbow surgery, and (iii) subsequent diagnosis of inflammatory or other disseminated neuropathy. Two groups served as controls for quantitative analysis of nerve-to-muscle signal intensity ratios: 20 subjects with typical focal ulnar neuropathy at the elbow and 20 healthy subjects. RESULTS: In the group of 21 patients with proximal ulnar nerve lesion extension, T2-w ulnar nerve signal was significantly (p<0.001) higher at upper arm level than in both control groups. A cut-off value of 1.92 for maximum nerve-to-muscle signal intensity ratio was found to be sensitive (86%) and specific (100%) to discriminate this group. Ten patients (48%) exhibited additional T2-w lesions in the median and/or radial nerve. Another ten (48%) had previously undergone elbow surgery without satisfying outcome. Clinical follow-up was available in 15 (71%) and revealed definitive diagnoses of multifocal neuropathy of various etiologies in four patients. In another eight, diagnoses could not yet be considered definitive but were consistent with multifocal neuropathy. CONCLUSION: Proximal ulnar nerve T2 lesions at upper arm level are detected by MRI and indicate the presence of a non-focal disseminated neuropathy instead of a focal compressive neuropathy.